Dates
Location
8:00 AM - 8:15 AM
Traci Wilgus, PhD; Rivkah Isseroff, MD; Timothy Koh, PhD
8:15 AM - 9:15AM
Michael Longaker, MD, MBA, DSc (hon) FACS
Details
9:15 AM - 9:30 AM
9:30 AM - 10:30 AM
Maksim Plikus, PhD; Raul Ramos, PhD; Brett Shook, PhD
Details
10:30 AM - 11:30 AM
Jeff Biernaskie, PhD; Sundeep Keswani, MD
Details
11:30 AM - 11:45 AM
11:45 AM - 12:45 PM
Benjamin Levi, MD; Hadar Lev-Tov, MD
Details
12:45 PM - 2:00 PM
Vickie Driver, DPM; Mitchell Sanders, PhD, Rivkah Isseroff, MD; Timothy Koh, PhD
Details
2:00 PM - 3:00 PM
Sasha Shafikhani, PhD; Paul Bollyky, MD, DPhil
Details
3:00 PM - 3:15 PM
3:15 PM - 4:15 PM
Boris Hinz, PhD; Kara Spiller, PhD
Details
4:15 PM - 4:30 PM
4:30 PM - 5:30 PM
Kirsi Isoherranen, PhD; Gary Sibbald, MD
Details
6:30 PM - 9:30 PM
Registered WHS members are invited to attend. Location TBD
7:00 AM - 9:00 AM
9:00 AM - 9:15 AM
9:15 AM - 10:30 AM
10:30 AM - 10:45 AM
10:45 AM - 11:45 AM
Maya Fayfman, MD; Samantha Minc, MD, MPH
Details
11:45 AM - 12:00 PM
12:00 PM - 1:30 PM
1:30 PM - 1:45 PM
1:45 PM - 4:00 PM
Traci Wilgus, PhD; Willeke Daamen, PhD; Piul Rabbani, PhD
Details
4:00 PM - 4:15 PM
4:15 PM - 5:15 PM
Marcella Gomez, PhD; Amit Gefen, PhD
Details
5:15 PM - 7:45 PM
7:00 AM - 9:00 AM
9:00 AM - 9:15 AM
9:15 AM - 10:15 AM
Details
Sasha Shafikhani & Lindsay Kalan
Daniel Gibson & Kellen Chen
Swathi Balaji & Harvey Himel
Mitch Sanders & Min Zhao
10:15 AM - 10:30 AM
10:30 AM - 11:30 AM
Details
Kyle Quinn & Rivka Stone
Daria Narmoneva & Nandini Ghosh
Kanhaiya Singh & Kara Spiller
Adrian Barbul & John Gwin
11:30 AM - 2:00 PM
12:15 PM - 2:00 PM
Geoffrey C. Gurtner, MD; Gautam Ghatnekar
2:00 PM - 2:15 PM
2:15 PM - 3:15 PM
Willeke Daamen, PhD; Jamal Lewis, PhD
Details
3:15 PM - 3:30 PM
3:30 PM - 4:30 PM
Lisa Gould, MD, PhD; Georgios Theocharidis, PhD; Helena Zomer, DVM, PhD
Details
4:30 PM - 4:45 PM
4:45 PM - 5:45 PM
Luisa Ann DiPietro, DDS, PhD
Details
5:45 PM - 6:00 PM
4:45 PM - 5:45 PM
Luisa Ann DiPietro, DDS, PhD
Details
5:45 PM - 6:00 PM
6:00 PM - 6:30 PM
Rivka Stone, MD, PhD; Subhadip Ghatak, PhD
Details
6:30 PM - 7:00 PM
7:00 PM - 7:15 PM
7:00 PM - 8:30 PM
9:15 AM - 10:15 AM
Paul Martin, BSc, PhD
Details
10:15 AM - 10:30 AM
10:30 AM - 11:30 AM
Details
Jamie Lee Burgess & Ivan Jozic
Dorothy Supp & Juan Cortes Troncoso
Subhadip Ghatak & George Theocharidis
Lauren Moffatt & Athena Soulika
11:30 AM
11:30 AM - 2:00 PM
P14.
Recent advances in 3D bioprinting have led to the development of innovative solutions for wound healing. Among various advanced dressings, hydrogel materials have gained significant attention for burn wound treatment in clinical practice. Advances in acute burn wound care have significantly decreased mortality rate in patients with severe burns. However, up to 70% of burn victims develop post-burn hypertrophic scars. In this study, 3D-printed dressings were fabricated with an extrusion-based bioprinter using bioinks consisting of gelatin, alginate, and bioactive borate glass (BBG). After ionic crosslinking, the 3D-printed bioactive hydrogel dressings were characterized and exhibited Young’s modulus in the range of normal skin, with 10-day stability in phosphate buffer saline. The hydration activity of bioactive hydrogel dressings were measured and compared to the FDA-approved commercial products. Over the course of 10 days, the bioactive hydrogels dressings steadily released 74% of their entrapped water, while the commercial products released their entire water content within 24 hours. The preclinical safety and efficacy of the dressings were investigated using a porcine model with a second-degree burn wound for 70 days. Our findings showed that the 3D-printed dressings with BBG exhibited faster wound closure with minimal scarring. Histological analysis suggested that 3D-printed dressings with BBG developed more uniform re-epithelialization and tissue remodeling compared to the FDA-approved commercial products. Our immunohistochemistry analysis revealed that BBG improved early angiogenesis and maturation of blood vessel in later stages of wound healing, which is associated with the therapeutic ions released from BBG particulates. After 70 days, the deposition of collagen fibers was measured at 95 ą 16 ľm and 278 ą 74 ľm with 21% and 10% basket-weave patterns, in the bioactive hydrogel dressing and commercial product, respectively. Finer collagen fibers, 27% decrease in ki67 and 36% increase in regeneration of hair follicles confirmed the enhanced scar preventing outcomes in bioactive hydrogel dressing compared to the commercial product. This can be attributed to the bioactive formulation and the 3D-printed porous surface, which promote a moist wound healing environment, thereby allowing for normal wound remodeling. Findings from this research provide valuable knowledge that advances bioprinting techniques in wound healing applications, specifically in the development of bioactive formulations for scarless wound healing.
P15.
BACKGROUND: Healing in obesity wounds is impeded for indistinct mechanism and lack of predictive indicators. Epidermal stem cells (EpiSCs) and adipocytes are important components in skin structure, metabolism and healing, while adipogenesis and adipocyte differentiation have been verified crucial for wound healing. As PPARgamma and HIF-1alpha are vital transcriptional factors balancing in adipogenesis and differentiation, we hypothesize that subcutaneous adipose protein expression ratios of PPARgamma/HIF-1alpha (P/H ratio) may reflect EpiSCs-adipocytes interaction and predict healing outcome in obesity wound. METHODS: A high fat diet-induced obesity model using Sprague-Dawley rats was established, setting groups of sham-injury (Sham), injury without cell transplantation (Injury), and injury plus EpiSCs transplantation, then a 6-mm diameter full-thickness excision was developed on the dorsal skin. 1Ũ10^5 epidermal basal stem cells isolated from neonatal mice skin and suspended in 30 ?l 1ŨPBS were injected subcutaneously into each wound in EpiSCs group, as equivalent 1ŨPBS was injected similarly in Sham and Injury groups. Skin wounds were harvested and subjected to histological investigations. RESULTS: Ameliorative histological healing and PerilipinA(+) adipocytes recruitment were found in EpiSCs group at 1, 3, 7 and 14 days after injury. Subcutaneous adipose P/H ratio determined by immunohistochemistry in EpiSCs group was decreased at 1 day but increased at 7 day (P<0.05, vs Injury), and it remained no significant difference yet a rising trend at 3 or 14 days (P>0.05, vs Sham or Injury). Subcutaneous adipose P/H ratio in Injury group was decreased at 7 day (P<0.05, vs Sham), and remained no significant difference with trends to rise at 1 or 3 days but decrease at 14 day (P>0.05, vs Sham). CONCLUSION: EpiSCs may resume PPARgamma/HIF-1alpha-balanced subcutaneous adipogenesis and adipocyte differentiation to promote healing in obesity.
P16.
Background: Acellular dermal matrix (ADM) helps wound healing by stimulating angiogenesis, acting as a chemoattractant for endothelial cells, providing growth factors, and permitting a substrate for fibroblasts to attach. The current standard for using paste-type ADM (CG Paste) in wound healing is direct application over the wounds. The major concerns regarding this method are unpredictable separation from the wounds and absorption into negativepressure wound therapy devices. This study aimed to investigate the effects of subcutaneous injection of paste-type ADM on wound healing in rats.
Methods: Full-thickness skin defects were created on the dorsal skin of rats. Eighteen rats were randomly divided into three groups and treated using different wound coverage methods: group A, with a saline dressing; group B, standard application of CG Paste; and group C, injection of CG Paste. On postoperative days 3, 5, 7, 10, and 14, the wound areas were analyzed morphologically. Histological and immunohistochemical tissue analyses were performed on postoperative days 3 and 7.
Results: Groups B and C had significantly less raw surface than group A on postoperative days 10 and 14. Collagen fiber deposition and microvessel density were significantly higher in group C than in groups A and B on postoperative days 3 and 7.
Conclusions: This study showed comparable effectiveness between subcutaneous injection and the conventional dressing method of paste-type ADM. Moreover, the injection of CG Paste led to improved wound healing quality through the accumulation of collagen fibers and an increase in microvessel density
P18.
Purpose: The purpose of this study is to develop a tunable hydrogel platform with encapsulated mesenchymal stem cells to enhance chronic wound treatment.
Methods: We synthesized a thiol methacrylate polyvinyl alcohol (TPVAMA) hydrogel system based on the thiol-ene reaction between methacrylated PVA (PVAMA) and thiolated PVA (TPVA). We introduced porous structures into the hydrogels via a gas-blowing process to improve nutrient transfer and waste removal, which could support cell viability. In this process, sodium bicarbonate and citric acid were combined into the system to create carbon dioxide, which was trapped during hydrogel fabrication to form a porous structure. Also, methacrylated gelatin (GelMA) was added into the system to improve cell attachment. Cells were mixed into hydrogel solutions prior to fabrication to obtain porous, cell-laden hydrogels. We obtained a library of hydrogel samples to utilize for further characterization.
Results: Cytocompatibility tests showed that all TPVAMA hydrogels have cell viability >95%, demonstrating this system is suitable for cell growth. 3D microscale images exhibited that we successfully encapsulated cells into hydrogels with varied dimensions. Viability of encapsulated A375 cells was measured over 14 days using a Live/Dead assay. At 14 days, viability was significantly higher in porous hydrogels with GelMA (porous-TPVAGelMA) than corollary non-porous hydrogels with (TPVAGelMA) and without GelMA (TPVAMA), with viabilities of 95ą3%, 84ą8%, and 71ą18%, respectively (n=3, p < 0.05). In the encapsulation of fluorescently labeled 3T3 fibroblasts, porous-TPVAGelMA showed a significant increase in the number of cells and cell spreading over 14 days compared with non-porous TPVAGelMA and TPVAMA controls. These results indicate that GelMA enhances cell proliferation and attachment, while porous structures aid in maintaining long-term cell viability. In degradation studies, hydrogels containing higher TPVA content degraded faster in hydrolytic and oxidative solutions. Thus, the degradation rate can be tuned based on the PVAMA and TPVA ratio, indicating that the hydrogel system could be designed to degrade after implantation while supporting healing.
Conclusion: These studies demonstrate that TPVAMA hydrogel foams are a potential platform for chronic wound dressings that are degradable, tunable, and suitable for cell encapsulation. Current work is focused on performing scratch assays and ex vivo pig skin experiments with encapsulated mesenchymal stem cell samples to observe the effects of the hydrogel system on healing processes.
P19.
P20.
P21.
Introduction:
Current substrates used to evaluate adhesive performance of medical products, such as stainless steel, show minimal correlation with human skin, as their surface energies and moduli are vastly different from the human skin they are trying to emulate. As such, there is an industry need for a substrate that would more accurately represent how adhesives perform on human skin.
Objective:
The purpose of this study is to evaluate a new substrate for its ability to produce peel force results similar to that of peel force results gathered from human skin. Using the layers of human skin as a basis for its construction, a prototype skin mimic was created as a multi-layered assembly: the top film layer (representing epidermis), the middle silicone layer (representing dermis), and the bottom anchoring layer (representing subcutaneous tissue/muscle/bone). The mimic was subsequently used to generate peel force data with nine medical tapes, which were then compared to internal clinical peel force data (t=0) of the same tapes for a performance evaluation.
Materials/Methods:
Four skin mimics of varying thickness (1.000”, 0.500”, 0.250”, 0.125”) were created. A tensile tester was used to conduct 180-degree peel tests, based off of ASTM D3330/D3330M-04(2018), in order to gather average peel force data for nine distinct medical tapes. Each tape was cut into 1”x5” strips, adhered with a standardized roller onto the skin mimic substrate, allowed to dwell for 1 minute, and peeled off the substrate with the tensile tester. The average peel force for each sample (N/in.) was calculated through the average value of a function (integral method) across a 3” peel interval. Resulting peel force averages for each tape, generated with the skin mimic, were then compared with a previously completed clinical study utilizing the same nine medical tapes.
Results/Discussion:
Four out of nine tapes (n=10) showed a statistically significant similarity between mean peel forces on the skin mimic vs human skin. The remaining did not exhibit similarity, primarily due to the large variability of the clinical data vs the high repeatability of the skin mimic data.
Conclusion:
The skin mimic showed a correlation with the data from the clinical study on human skin, but with a higher level of repeatability as indicated by the low standard deviation of skin mimic data. A high level of repeatability will be critical when evaluating adhesives for changes in performance, as it becomes increasingly more difficult to attribute differences in results to variations in the adhesive when variability is high due to the method and/or study participants.
P22.
Background: Pressure ulcers (PU) are injuries to the skin and underlying tissue localized over a bony prominence. Major surgical complications include ulcer recurrence, wound dehiscence, hematomas, and infection which pose significant morbidity to patients. The objective of this study is to characterize the relationship between BMI and early and late wound complications following surgical closure.
Methods: A single institution prospective study was conducted to include patients with a stage III/IV pressure ulcer admitted for surgical closure. The subjects were monitored for 14 days post-closure (POD-14) for assessment of early wound status and complications, including moisture, maceration, drainage, dehiscence, epidermolysis, necrosis, and demarcation.
Results: 68 patients were included. 13% of patients were underweight, 29% normal weight, 35% overweight, and 22% obese. POD-14 complications occurred in 22% of underweight patients, 15% of normal weight, 38% of overweight, and 40% of obese patients. There was a significant difference between POD-14 complication rates across underweight, normal weight, and elevated BMI groups (p=.002). The odds ratio of complication occurrence given an elevated BMI compared to a normal BMI was 4.14 with a relative risk of 3.07. Of all recorded complications, 75% of patients were overweight or obese. Complication rates were not significantly different based on osteomyelitis status. The most common cultures identified in wounds were P. aeruginosa, S. aureus, and E. coli. Negative cultures were found in 22% of closed wounds and 13% of open wounds.
Conclusion: Our findings suggest that BMI may be correlated with early wound status and the incidence of postoperative complications, while osteomyelitis status may not. Future studies should further evaluate the effect of BMI on pressure ulcer associated complications. This may further guide preoperative planning and patient expectations.
P23.
Background
Diabetes is a common medical condition with numerous comorbidities including chronic wounds. Impaired wound healing in diabetes has been associated with inflammation and oxidative stress secondary to reactive oxygen species (ROS), which have traditionally been measured by evaluating dysregulation in enzymes that produce ROS. ROS also act as second messengers for cell populations present within diabetic wounds to stimulate further inflammation, resulting in a cycle of chronic inflammation and oxidative stress. Fibroblasts are a key cellular population involved in wound healing and have historically been identified to play a role in extracellular matrix formation, inflammation, and angiogenesis. Given that ROS interact with other cell populations beyond inflammatory cells, we theorized that fibroblasts may interact with ROS beyond their known cellular function and contribute to the overall milieu of the wound. We therefore hypothesized that both whole blood and dermal fibroblasts isolated from diabetic mice would demonstrate increased ROS production as measured by electron paramagnetic spectroscopy (EPR), which allows for direct measurement of ROS rather than just enzymatic markers.
Methods
Fibroblasts were isolated from skin of 12-week-old female diabetic (db/db) and heterozygous (db/+) control mice (N=1 per group) and cultured in low-glucose Dulbecco’s Modified Eagle Medium (DMEM) with 10% fetal bovine serum (FBS) and 1% antibiotic-antimycotic in tissue culture flasks. Once confluence was achieved, fibroblasts were passed into 6-well plates (N=6 per group) and cultured until 80% confluence was reached. Whole blood was extracted from 12-week-old female diabetic and heterozygous control mice (N=2 per group). Production of ROS was evaluated with electron paramagnetic resonance (EPR) spectroscopy using a hydroxylamine probe that upon the reaction with ROS generates a nitroxide radical that can be detected by EPR.
Nitroxide levels generated from both whole blood and cultured fibroblasts treated with the EPR probe and normalized to protein concentration were compared between diabetic mice and heterozygous controls.
Results
Fibroblasts from diabetic mice demonstrated significantly higher ROS production compared to heterozygous controls (p=0.042). Similarly, whole blood from diabetic mice demonstrated significantly higher ROS production compared to heterozygous controls (p=0.047).
Conclusions
ROS production was significantly elevated in dermal fibroblasts of diabetic mice compared to controls, suggesting that fibroblasts may play a role in the production of ROS that leads to oxidative stress. Additionally, whole blood of diabetic mice demonstrated upregulation of ROS, suggesting the presence of a systemic effect. Dermal fibroblasts remain a key regulator of impaired wound healing in diabetes due to multiple mechanisms and may serve as a target for potential therapeutics.
P24.
Background: Pressure ulcers are injuries to the skin and underlying tissue that often develop into chronic wounds and can significantly impact quality of life. After surgical closure, many patients experience complications such as dehiscence, maceration, drainage, and necrosis, and may require long-term rehabilitation to achieve functional recovery. The objective of this study is to evaluate the association between wound characteristics prior to surgical closure and wound healing outcomes including complication rates and disposition.
Methods: In this prospective study, patients with grade III/IV buttock pressure ulcers were admitted for surgical closure and observed post-operatively for at least 14 days. Wound characteristics upon admission, such as wound location, size of wound (length, width, depth), and previous wound treatment (previous closure, debridement, negative pressure wound therapy, hyperbaric oxygen, biologics, revascularization) were recorded. Wound volume was estimated by multiplying length, width and depth. Outcome measures included 2-week complication rates, length of hospital stay, disposition, and wound closure rates at 2 weeks, 1 month, 6 months, and 12 months. Odds ratios and t-tests were used to analyze outcomes.
Results: Of a total of 68 patients who completed the study, 36 (53%) had ischial wounds, 25 (37%) had sacral wounds, and 7 had wounds in other locations. 11% of patients with ischial wounds experienced complications, while 44% of those with sacral wounds experienced complications (OR=0.16, 95% CI 0.04-0.59). The average number of complications per patient was 0.19 in patients with ischial wounds and 0.67 in patients with sacral wounds (p = 0.01). Patients with sacral wounds also had a longer average hospital stay than those with ischial wounds, by 1.7 days (p = 0.04). Increased wound volume was associated with lower chance of closure at 14 days (p = 0.006), but did not have an effect on closure rates at long-term follow-ups. Increased wound length was also independently associated with lower chance of closure on day 14, although this result only approached significance (p = 0.056). Patients who did not receive any previous treatments were more likely to be discharged to a long-term care facility than patients who had previous treatment (OR=6.22, 95% CI 1.07-36.2). The average number of complications per patient was 0.09 for patients who had previous wound closure and 0.42 for patients who had not had previous closure (p = 0.01).
Conclusion: Overall, this study found that wound characteristics prior to surgical closure, including size, location, and previous treatments, have a significant impact on post-operative complication rates and disposition in patients with grade III/IV buttock pressure ulcers. These findings warrant further investigation and can help guide management and pre-operative counseling.
P25.
BACKGROUND. Ostomy surgery is often the only effective treatment for diseases affecting normal digestive or urinary function. The resulting stoma, or opening, in the abdomen is affixed with a waste collection pouch that is secured to the surrounding skin with adhesive tape. Ostomy pouches are Class I medical devices and must not only adhere to the skin and protect it from body waste, but also be amenable to routine removal and re-application for the duration of the treatment. Repeated removal of adhesives and exposure to bodily wastes from the stoma (dejecta) causes peristomal skin damage that can lead to complications and reduced quality of life.
METHODS & RESULTS. Our goal is to develop novel adhesive formulations that can a) adhere for extended periods of time; b) be removed with minimal skin trauma; and c) minimize the impact of stoma leakage. Human clinical modeling of peristomal skin irritation is costly and difficult to achieve in healthy volunteers, therefore clinical models are challenging as a high-throughput screening tool for formulation development. Therefore, to achieve our goal we developed an ex vivo model of peristomal skin using de-identified, discarded abdominoplasty tissues to identify strong novel adhesive formulation candidates to move into clinical models. Our current objectives are to understand the effects of repeated tape-stripping with 2 different hydrocolloid adhesive formulations and the damage caused to skin by a mixture of digestive enzymes. Morphological analysis of H&E-stained cross sections of tape-stripped tissue (applied and removed five times) revealed distinct differences in the extent of damage to the stratum corneum, ranging from no damage to complete loss with exposure of the stratum granulosum. Transepidermal water loss (TEWL) readings taken immediately after each stripping event correlated with observed epidermal damage. These TEWL results align with results from prior clinical studies of these adhesives. To understand the skin damage resulting from exposure to digestive enzymes in dejecta, we topically applied a cocktail of trypsin, chymotrypsin, and elastase for 1 h to skin tissue. Enzymatic exposure caused significant decompaction of the stratum corneum and ablation of the stratum granulosum, as determined by H&E staining. Moreover, the enzymes significantly reduced the immunofluorescent expression of epidermal barrier proteins filaggrin and loricrin.
CONCLUSIONS. Taken together, these results show significant mechanical and enzymatic epidermal barrier damage and modeling of peristomal conditions. Moving forward, we will combine tape-stripping with enzyme exposure to more closely model the combination of factors affecting the peristomal skin and characterize additional adhesive formulations with improved skin protective capabilities.
P26.
P27.
Introduction:
Epithelial-to-mesenchymal transition (EMT) is a well studied biological phenomenon that takes place during various biological processes including wound healing, Type II EMT. Embryos undergo scarless wound healing while adult wound healing creates a scar. The wound healing extracellular matrix (ECM) varies between adults and embryos. Embryos have higher levels of hyaluronan (HA) and type III collagen fibers, while the adult ECM is marked by denser, aligned collagen bundles and reduced HA. Various studies have reported that HA helps keratinocyte proliferation and migration during wound healing. It remains unknown how different HA topographies affect the proliferation and migration of keratinocytes. To address this gap, we created synthetic matrix analogs that are capable of representing different HA topographies using hyaluronan binding peptide (HABP) studied the role of HA topography on EMT.
Methods:
Synthesis and Surface Modification of PCL Fibers. Polycaprolactone (PCL) fibers with diameters 0.5µm and 5µm were made through electrospinning and functionalized with HABP through aminolysis as previously reported [4]. Fiber characterization was performed through SEM and water contact angle (CA) analysis. Cell Proliferation and Migration. Primary human epidermal keratinocytes were used to study EMT. Cell proliferation was studied using Ki67, pico green, and presto blue assays. Cell migration was studied using a transwell migration assay. EMT Marker Quantification. The concentration of common EMT markers was found using western blot. Cell Morphology. Cell morphology was analyzed through fluorescent microscopy where the nucleus and f-actin were stained. In the epithelial state, cells display cortical actin in the membrane cortex, which transitions into stress fibers in the mesenchymal state.
Results:
We found PCL scaffolds had an average CA of 82.84 ± 17.48° and with the addition of HA the average CA was 77.57 ± 16.52°. With just the addition of HABP to the scaffolds the average CA was 11.88 ± 19.35° and with the addition of HABP and HA the average CA was 4.38 ± 10.72°. The addition of the peptides makes the surface hydrophilic with HABP making the surface completely hydrophilic. Ongoing experiments are currently focusing on understanding the role that HA topography plays has on EMT by measuring the concentration EMT markers. Fluorescent images of epithelial cells on the different surfaces will be taken to determine if the addition of a peptide causes cells to take on more of a mesenchymal shape. The results of this experiment will shed light on how topography influences the factors that trigger cells to undergo EMT. The goal of this study was to determine the effect of different the impact of various hyaluronan topographies on cells during Type II EMT.
P28.
Background: In comparison to skin wounds, oral mucosal wounds heal more rapidly with significantly less inflammation, faster re-epithelialization, and minimal scarring. Our lab has previously shown that skin and oral excisional biopsy mucosal wounds exhibit site-specific differences in their genetic response to injury and that intrinsic keratinocyte characteristics may be one differentiating factor. The aim of this study was to investigate whether the intrinsic differences between oral and skin keratinocytes would be reflected in their transcriptome at baseline and after injury.
Methods & Materials: In this study, we used two keratinocyte cell lines: 1) hTERT-immortalized gingival keratinocytes (TIGK) and 2) spontaneously immortalized skin keratinocytes (HaCaT). RNA was isolated from HaCaT and TIGK at 0-, 6-, and 24-hours post-scratch (N=3). Following DNase treatment, RNA-sequencing was performed and transcriptomic changes in response to injury were compared between HaCaT and TIGK. Genes that were significantly downregulated (p<0.05) in HaCaT versus TIGK underwent gene ontology (GO) enrichment analysis and reactome pathway analysis. GO terms were annotated to biological processes (BP), cellular components (CC), and molecular function (MF). Additionally, HaCaT were stably transfected to overexpress Basic Leucine Zipper ATF-Like Transcription Factor 3 (BATF3-OvExp) or with an empty vector control (EV-Ctrl). Cellular migration and proliferation were assessed for BATF3-OvExp and EV-Ctrl (N=8-10). Expression of genes down-stream of BATF3 were assessed via RT-PCR (N=3-4).HaCaT migration was also assessed following pre- and post-scratch treatment with Interferon (IFN) Type I (N=10-12).
Results: Analysis of differentially expressed transcription factors found that BATF3 was significantly downregulated in HaCaT versus TIGK for all time points (p<0.05). BATF3 overexpression significantly enhanced HaCaT migration and expression of down-stream genes (p<0.05) but had no effect on proliferation. Comparison of transcriptomic changes in response to injury between HaCaT and TIGK also identified differences in expression of genes related to matricellular proteins and IFN signalling. Following pre- and post-scratch treatment with IFN Type I, HaCaT exhibited significant enhancement of migration (p<0.05).
Conclusions: Our results demonstrate that HaCaT and TIGK exhibit differences in baseline behavior and transcriptomic responses to injury. Furthermore, both BATF3 overexpression in HaCaT and IFN Type I treatment enhanced cellular migration, which may be beneficial to wound healing. The results suggest that transcriptomic differences between oral and skin keratinocytes at baseline and in response to injury underlie the distinct wound healing phenotypes observed in skin and mucosal wounds.
Funding: R01 GM050875, R35 GM139603, F31 DE028747, F31 AR082287.
P29.
Background:
Aging can diminish wound healing due to insufficient tissue oxygenation. Hyperbaric oxygen therapy (HBOT) poses systemic risks, while topical oxygen treatments (TOT) offer a safer localized alternative. This study examines TOT’s impact on wound healing and how patient and wound characteristics influence its effectiveness.
Methods:
A retrospective chart review (8/1/2011 – 7/1/2023) analyzed patients aged 23 to 97 with any wound etiology who used TOT (GWR Medical inc.) after unsuccessful alternate treatments. The device was used 90 minutes daily for four days, followed by a three-day break. Patient demographics (gender, age, race, smoking status, comorbities, radiation usage, nutrition level), wound details (dimensions, age, location, etiology), and device usage interruptions were collected from EPIC. Comorbidities were subdivided into body-system categories. Wound dimensions were measured using a centimeter ruler. Healing was gauged by percent changes in surface area, depth, and volume between the initial and final measurements. Analysis included two linear mixed effects (LME) models—one for comorbidity groups and one for individual comorbidity counts. Variables with high collinearity and variance inflation factor (VIF) > 10 were removed.
Results:
From 45 patients, 84 wounds were reviewed, averaging 1.86 wounds and 7.27 comorbidities per individual. Wound sizes ranged from 0.08 cm2 to 482.5 cm2 (median: 10.25 cm2). About 68% of wounds shrank, 2% remained unchanged, and 30% enlarged. Complete healing was more prevalent in nourished patients (94%), those without radiation history (88%), and non/former smokers (53%, 41%). No wound exceeding 27 cm2 completely healed.
The LME model with comorbidity count showed the percent of days used enhanced healing for surface area (? = 1.092, p = 0.017), depth (? = 0.954, p = 0.030), and volume (? = 1.021, p = 0.027). Certain locations (foot: ? = 1.597, p = 0.022; leg: ? = 1.259, p = 0.027; toe: ? = 2.498, p = 0.003) and being male (? = 1.537, p = 0.012) promoted healing. Initial depth (? = -0.472, p = 0.018) and white ethnicity (? = -2.033, p = 0.013) reduced healing. Overall comorbidity count was insignificant (? = 0.093, p = 0.422).
The LME model with comorbidity categories found that being male (? = 1.486, p =0.019), percent of days used (? = 1.002, p = 0.032), and bone disease (? = 2.327, p = 0.008) increased surface area healing, while initial depth remained detrimental (? = -0.519, p = 0.007). Age was a non-factor in both models.
Conclusion:
Uninterrupted TOT usage promoted surface area, depth, and volume healing, while greater initial depth hindered healing. Given that certain wound and patient characteristics can influence healing with TOT, physicians should consider these factors when tailoring patient treatment plans.
P30.
Purpose:
A novel peel and place† dressing for use with negative pressure wound therapy (NPWT)* has been developed that addresses the challenges of tissue ingrowth with reticulated open cell foam (ROCF)^ dressings, while exhibiting a modified tissue strain environment and promotion of wound healing associated biomarkers.
Materials and Methods:
All animal work was approved by the relevant IACUC and complied with applicable national and local regulations. Full-thickness excisional paraspinal wounds were created in 11 swine. Continuous, -125 mmHg was applied to both peel and place and ROCF dressings for 7 days with a single dressing change on day 4. Biopsies were collected from wound beds at study termination. Total protein was extracted and analyzed using multiplex protein assays.
Finite element modeling of tissue strains was completed using clinically relevant dimensions and mechanical properties. Simulations in this environment were completed for ROCF and novel peel and place NPWT dressings under -125 mmHg.
Results/ Discussion:
Multiplex protein assays showed a relative increase of cytokines and growth factors in tissues managed with the peel and place dressing compared to ROCF. Notable significant differences (p?0.05) include greater relative concentrations of HB-EGF (19.36 vs. 5.381 ng/g), PDGF-AA (15.46 vs 11.14 ng/g), TGF-a (8.253 vs. 1.861 ng/g) in peel and place managed wounds compared to ROCF.
Finite element analysis (FEA) of novel dressing under -125 mmHg produced peak and lower tissue strains of 18% and 4%, respectively, that extended several mm into the wound bed, while ROCF exhibited peak strains of 40% at shallower depths. ROCF also produced downward tissue displacement at wound-foam strut contacts. Downward displacement was seen in the peel and place dressing along the wound edge. Overall, tensile strains were predicted to be more homogenous at the deep wound bed in the peel and place dressing model.
Conclusion:
Cells respond to imposed forces/strains by producing biochemical stimuli.? The homogenous tissue strains and deep propagation of tensile strains seen in the novel dressing FEA model could explain the greater levels of cytokines/chemokines and growth factors compared to ROCF.
†Novel Peel and Place Dressing (3M Company, San Antonio, TX); * 3M™ V.A.C.® Therapy; ^ 3M™ V.A.C.® Granufoam™
? Dunn, S. L., & Olmedo, M. L. (2016). Mechanotransduction: Relevance to Physical Therapist Practice Understanding Our Ability to Affect Genetic Expression Through Mechanical Forces. Physical Therapy, 96(5), 712-721. doi:10.2522/ptj.20150073
P31.
Background: Effective treatment of wound-site infections in diabetic foot ulcer (DFU) patients is crucial for a good prognosis. Recently, 16S rRNA next-generation sequencing (NGS) has been the main focus of research for accurately detecting wound-site microbes, which is vital in optimal antibiotic treatment. We compared the conventional culture-based detection method to the 16S rRNA NGS method to predict the DFU treatment outcomes.
Methods: Wound-site samples from 47 DFU patients who were treated at Korea University Guro Hospital from February 2021 to November 2021 were analyzed with both conventional culture and NGS methods. We set the primary outcome as the healing status of each patient, which was assessed using the SINBAD score and amputation status, and the secondary outcomes as wound-site ischemia and infection control.
Results: The NGS method detected a broader range of microbial species (Shannon index=1.369 ą 0.755, Simpson index=2.987 ą 1.383) compared to the conventional culture method (Shannon index=0.693, Simpson index=1.269). Sixteen species were found using the two methods, which were all anaerobes. The most significant discordance of detected species was found in the SINBAD?3 group (40.79%), and within that group, the patients with an absence of ischemia but poor infection control had the largest discordance (85.22%). Among the microbes detected significantly different between the two methods, B.fragilis, S.agalactiae, S.aureus, and S.constellatus were associated with poor prognosis, which were mainly detected in NGS than culture.
Conclusion: Early studies now suggest that 16S rRNA NGS may be an effective diagnostic tool for treating diabetic foot infection. We look forward to larger pivotal studies to confirm these initially promising findings.
P32.
P33.
Chronic wounds become colonized by pathogens, primarily bacteria, and these infections often result in the development of biofilms. Unfortunately, treatment with antibiotics alone often fails to resolve chronic wound infections, in part because antibiotics are ineffective at killing bacteria in biofilms. Persistent biofilms in chronic wounds significantly delay wound healing. The purpose of this study was to determine the effects of N-acetyl-cysteine (NAC), Ciprofloxacin (Cipro), and Gentamicin (Gent) on Enterobacter cloacae (Ec), Pseudomonas aeruginosa (Pa), and Staphylococcus xylosus (Sx) biofilm, alone and in combination. We also tested the effects of these treatments in presence or absence of oxidative stress. 1×10 6 cfu/200痞 of bacteria were cultured in 96-well plates and allowed to form biofilm for 24 hours. The biofilms were then treated with NAC (20 mg/ml) or NAC + Gent (100 痢/ml) + Cipro (10痢/50痞) for another 24 hours. The biofilm was stained with 0.1% crystal violet, distained with 95% ethanol, and analyzed at OD590 to measure the amount of biofilm present after treatment. To create the conditions for oxidative stress, H 2 O 2 at a final concentration of 500然 was used. NAC had a significant effect on Ec, Pa, and Sx individually in decreasing the amount of biofilm, but its effects were significantly lessened when used under oxidative stress conditions. For Ec, Pa, and Sx individually, NAC + Gent + Cipro was less effective than NAC alone at decreasing the amount of biofilm in non-oxidative stress conditions. There was no significant difference for Ec and Sx alone between NAC and NAC + Gent + Cipro under oxidative stress conditions. However, for Pa, NAC + Gent + Cipro was more effective at decreasing the amount of biofilm under oxidative stress conditions. For the combinations Ec+Pa, Ec+Sx, and Pa+Sx, there was no significant difference between the effects of NAC alone versus NAC + Gent + Cipro under conditions without oxidative stress. Under conditions with oxidative stress, NAC + Gent + Cipro was significantly better at decreasing the amount of biofilm for the combinations Ec+Pa, Ec+Sx, and Pa+Sx. For the combination Ec+Pa+Sx, without conditions of oxidative stress, there was a significant difference between NAC alone and NAC + Gent + Cipro, as the latter was more successful at decreasing the amount of biofilm. Under conditions with oxidative stress, there was no significant difference between NAC alone and NAC + Gent + Cipro for Ec+Pa+Sx. In conclusion, NAC, has proven to be able to significantly decrease the amount of biofilm with and without oxidative stress under most conditions. However, under other conditions NAC is aided by Gent and Cipro. Regardless of whether the bacterial strains are alone or in combination with each other, the effect of NAC is significant in decreasing the amount of biofilm, though sometimes it needs the assistance of the antibiotics.
P34.
The function of the epidermis and response to wounding are significantly compromised during the development of the cutaneous inflammatory condition hidradenitis suppurativa (HS). Resident HS keratinocytes erroneously migrate into the surrounding area forming pathognomonic epithelial, intra-dermal tunneling wounds, which are primary drivers of chronic inflammation. In addition, HS tunneling wounds are colonized by anerobic bacteria that form treatment-resistant biofilms. Persistent biofilms are hypothesized to contribute to an aberrant inflammatory response and, subsequently, the relapsing nature of HS tunnels. Here we performed the first pilot longitudinal study to evaluate the effectiveness of antibiofilm therapy for HS tunneling wounds. HS Subjects (n=15) with confirmed tunnels were recruited to the study and pre-treatment lesional tissue was collected to evaluate the host response and microbiome composition. Subjects then instilled the antibiofilm surfactant gel daily into the tunneling wounds, and tissue was collected 28 days after the procedure for evaluation of the inflammatory response and bacterial load by 16s rDNA sequencing. RNA was isolated before and after treatment and host response was analyzed with Nanostring’s Ncounter technology. We observed 93% clinical, tunneling wound resolution and overall reduction of scarring at an average of 12 days after daily instillation of antibiofilm surfactant gel in HS tunneling wounds. Clinical findings correlated with the significant attenuation of the inflammatory response after anti-biofilm treatment, with marked reduction in INFg, IL-17, IL-6, IL-8, and TNFa signaling. Furthermore, the treatment resulted in reduction of bacterial load, and restoration of microbial dysbiosis reflected in lower abundance of anaerobic pathogens and restoration of commensal bacterial genera. Our study highlights the importance of therapeutic targeting of bacterial biofilms in HS tunneling wounds. We conclude that anti-biofilm therapeutics offer a novel treatment approach to suppress inflammation, restore healthy microbiome and alleviate clinical symptoms in affected patients.
P35.
Purpose of the Study: The incidence of Chronic Venous Leg Ulcers (CVLU) is escalating among the adult and elderly population, posing a substantial burden on patients and the healthcare system due to its high recurrence rate and chronicity. This literature review aims to explore the influence of microRNAs associated with wound healing in CVLU patients.
Methods: A comprehensive search on PubMed and EMBASE was conducted in October 2023 to identify studies analyzing microRNAs involved in CVLU wound healing. Ninety-six records published in English over the past decade were retrieved, leading to the selection of 13 studies for full-text review. After applying inclusion/exclusion criteria, five studies were chosen for detailed analysis.
Results: Biopsy samples from 56 CVLU patients and one sample from adipose tissue were collected, alongside three studies utilizing wound samples from healthy volunteers for comparison. Overexpression of miR-221, miR-222, miR-92a, and miR-301a-3p was found to negatively impact angiogenesis. Conversely, miR-296 overexpression upregulated VEGR2 expression, facilitating angiogenesis. MiR-301a-3p upregulation exacerbated vascular endothelial cell damage by targeting IGF1, mediating inflammatory responses, increasing HUVEC apoptosis, and elevating oxidative stress, ultimately impairing wound healing. Additionally, miR-19a/b and miR-20 upregulation were associated with downregulation of keratinocytes’ inflammatory response via the NF-kB signaling pathway, restoring wound healing in vitro and in vivo using an animal model. Conversely, miR-34a and miR-34c upregulation impaired wound healing by enhancing keratinocytes’ inflammatory response through the miR-34-LGR4 axis.
Conclusion: MicroRNAs play a pivotal role in regulating angiogenesis, inflammatory responses, cell migration, and wound healing. Identifying specific microRNAs and their target pathways offers valuable insights, guiding researchers towards potential therapeutic targets for treating chronic venous leg ulcers.
P36.
The use of the domesticated swine proves to be an integral part of advancing our understanding of dermatology in human skin due to its similarities to humans and the use of it as a model. A few reports in the literature have noted differences in healing in excisional wounds in different cephalo-caudal anatomical locations. We hypothesized that the differences in healing may be related to possible differences in the thickness of the dermal or adipose layers, as they contribute to the healing process. Here we addressed this question of how these layers vary in thickness when excisional wounds are created in different anatomical locations, albeit when excising down to the same anatomical landmark of the panniculosus carnosus muscle in the attempt to create equivalent wounds. Eight full-thickness wounds (1.6cm in diameter for 2cm.2 area) were created along the dorsal region of the in Yorkshire/Landrace crossbreed pigs along a cephalo-caudal axis, with each wound being 3cm separated from the adjacent one. Both the depth of the resultant wound and the excised tissues were measured. At day 7 post-wounding, the entire wound was excised and fixed and sectioned, and the thickness of the dermal and subdermal tissues at the wound margin was measured histomorphometrically. Wound depths of the excised cranial wounds averaged 8.8cm while those in the caudal area averaged 6.7cm (N=28 wounds, 0.01 P-value). Histomorphometric analysis of the dermal and subdermal layers adjacent to the excised wounds showed that in the cranially located wounds the dermis averaged 2515um as compared to 2747um in caudally located wounds (N=24, 0.05 P-value), and the subcutaneous layers measured 6674um and 4584 in the cranial and caudal wounds respectively (N=24, 0.0001 P-value). This study demonstrates that despite excising down to the same anatomical landmark in an attempt to create identical wounds, the dermal and subcutaneous tissues are thicker in cranial areas as compared to the caudal wounds. Surprisingly, however, on day 7 post wounding, there is no difference in the wound re-epithelization between these two areas. Additional studies examining healing at later time points may reveal differences in healing.
P37.
Background:
Pressure injury (PrI) prevention is a major challenge for many people with limited mobility, often leading to prolonged bedrest, hospitalization and even death. Clinical practice guidelines recommend weight-shifting every 20 minutes, but this is difficult when busy with activities of daily living. Prevention thus remains a major challenge which we have found that intermittent gluteal neuromuscular electrical stimulation (iGSTIM) can address. Unfortunately, while surface gluteal electrical stimulation has been used for short periods it has limited efficacy for long term use. A fully implanted iGSTIM system was requested by many people desperate for a new alternative to PrI prevention. iGSTIM using bilaterally implanted electrodes provides sustained and effective, regular and automatic weight-shifting, which increases muscle bulk, reduces intramuscular adipose tissue and maintains improved tissue health over many years.
Methods:
Newly emerged technologies have enabled us to build soft flexible stimulators and electrode arrays that are implantable and biocompatible for implantation. The mechanically biomimetic and functionally flexible 4-channel stimulator, flexSTIM can provide clinically relevant weight-shifting for up to 14 hours/day. Preliminary biocompatibility testing of flexSTIM has been completed in five New Zealand White rabbits.
Results:
Biocompatibility testing of system components implanted for a six month period found that flexSTIM and the intramuscular electrodes were well tolerated. We also have successfully created and reproduced a rabbit spinal injury survival model with animals exhibiting sustained loss of unilateral hind limb function while remaining healthy with independent bowel and bladder function.
Conclusions:
Further development will include review and refinement of pre-clinical protocols as needed for evaluation of sustained flexSTIM function, reliability and safety.
P38.
Purpose: The purpose of this study was to develop a real-time chronic wound infection monitoring sensor through the evaluation of a whole-cell Escherichia coli biosensor for the detection of N-(3-Oxydodecanoyl)-L-homoserine lactone (3OC12HSL), an important autoinducer in the quorum sensing network of Pseudomonas aeruginosa.
Methods: To simulate chronic wound fluid conditions in vitro, various concentrations of Lysogeny broth (LB) were combined with artificial wound fluid exudate (AWFE, Biochemzaone) to grow P. aeruginosa. This fluid was then used to determine ranges of 3OC12HSL detectable by our synthetic biosensor. P. aeruginosa was grown in varying concentrations of LB and AWFE, starting at 25% LB mixed with 75% AWFE and moving down to 5% LB and 95% AWFE; negative controls of (100% LB) and positive controls (100% AWFE) were also tested. A growth curve for the bacteria was generated via absorbance detection at 600nm. A crystal violet assay was also performed at 590nm for all media types.
A synthetic gene network, including the lasR, amilCP (colorimetric reporter with blue color), and kanamycin resistance genes, were added to a DH5? E. coli host and selected by plating in LB agar + 50ÁM/mL kanamycin. The colonies were picked and grown overnight in LB with kanamycin. Cultures are then resuspended in fresh LB with kanamycin and added to 12 conical tubes. 10ÁM/mL of exogenous 3OC12HSL was added to the first tube and serially diluted by 1mL through the final tube (1:4 dilution each tube). The different concentrations and bacterial and media controls were plated in triplicate in a 48-well plate and read at 588nm, 600nm, and 700nm to quantify amilCP expression.
Results: Ten tests were performed for the differing media concentration growth curves in four replicates (n = 40) per concentration (total n = 280). A single-factor ANOVA and Tukey tests were used to determine which concentrations differed for biofilm analysis. There was a statistically significant increase in biofilm growth for the 100% LB condition compared to any other condition containing AWFE where p = 0.05. Additionally, biofilm growth decreased with increasing concentration of AWFE across all conditions where p = 0.05. Two tests were performed to detect exogenous 3OC12HSL in three replicates (n = 6). Currently, our designed biosensor has been able to detect concentrations of 3OC12HSL above 0.15nM/mL of 3OC12HSL.
Conclusions: The concentration of LB plays a significant role in P. aeruginosa growth and biofilm development. With future tests, we can predict which concentration accurately describes clinical samples. The synthetic biosensor can detect exogenous 3OC12HSL to about 0.15nM/mL in liquid cultures. Further testing will allow for more accurate quantification of 3OC12HSL toward real-time infection diagnosis.
P39.
P40.
The pathophysiology of non-healing wounds has been associated with the colonization of multispecies bacteria as well as poor vascularization in wounds. Thus far, each of the above aspects have been separately investigated and an integrated approach to simultaneously addressing these issues in a cost-effective single drug delivery platform has yet to emerge. The objective of this study was to develop copper nanoparticle (CuNPs)-based injectable scaffolds with antibacterial as well as proangiogenic properties for wound healing. Our strategy relies on the current scientific knowledge that (1) copper has great potential to as antimicrobial agent for both topical and systemic administration, while it is less harmful to the host cell because copper is an essential metal for life; (2) copper is a co-factor for many angiogenic promoters and mediators, and can switch on such molecules from the quiescent to pro-angiogenic state; (3) Ascorbic acid exhibits dual functions of pro-oxidative and antioxidative activities depending on its concentrations. In this study, CuNPs (20-120 nm) were synthesized using a green hydrothermal synthesis method. The antibacterial and proangiogenic capabilities of CuNPs were fine-tuned by optimizing the dose of vitamin C (VC) that reacts with CuNP. The antibacterial activity of CuNPs was significantly enhanced when combined with higher concentrations of (VC), which synergistically enhanced a Fenton reaction for reactive oxygen species generation (ROS). The threshold level of VC for triggering a Fenton reaction with CuNP was measured to be 10 mM, where the MICs of CuNPs were measured to be 20 mM for both (methicillin sensitive and methicillin-resistant S. aureus), and 5 mM for both (drug-sensitive and drug-resistant P. aeruginosa), suggesting a potent antibacterial activity of CuNP/VC cocktail against broad-spectrum bacterial species. The proangiogenic activity of CuNPs was assessed by tube formation assay, in which the treatment of CuNPs (80 nm) on HUVEC significantly increased endothelial tube formation in a dose dependent manner at lower doses of VC (<100 mM). An injectable formulation of hydrogel scaffold was prepared by incorporating CuNP and VC (at 10xMIC) in a thermos-reversible Pluronic F-127 hydrogel (25%), which enabled controlled release of CuNPs and VC. The bactericidal capacities of the CuNP/VC-loaded hydrogel formulation was assessed using a standard well diffusion assay against S. aureus and P. aeruginosa. The results showed a significantly increased inhibition of bacterial growth for the gel with both CuNPs and VC, compared to the gel with either CuNP or VC only (p<0.05). In summary, our results support the feasibility of CuNP-based multifunctional hydrogel scaffold that facilitates the eradication of bacterial pathogens as well as proangiogenic response for wound healing.
P41.
BACKGROUND. Transepidermal water loss (TEWL) is an indicator of skin barrier disruption following skin stripping injury. Consequently, TEWL is routinely used to assess skin response to candidate ostomy barrier formulations, with low TEWL readings suggesting that a barrier formulation is gentle on the skin when removed. When utilizing TEWL, however, studies have failed to account for potential differences, or interactions between anatomical sites on the abdomen. This study sought to determine whether TEWL response to repeated mechanical stripping was equivalent at different distances from the abdominal midline & across bilaterally symmetrical sites on the abdomens of healthy volunteers.
METHODS. Following acclimation in an environmentally-controlled room & measurement of baseline TEWL at each site, a coupon of an aggressive hydrocolloid adhesive A was applied to site 1 (S1) & 3 coupons of a gentle hydrocolloid adhesive B were applied to a row of 3 sites (S2, S4, S5, right to left) across the abdomen of 50 healthy subjects . A midline untreated site (S3) served as a control. This arrangement of sites permitted comparison of bilaterally symmetrical treatments to adjacent treatments to detect anatomical effects on TEWL in response to injury. Seven cycles of adhesive application & removal after 45min were performed. TEWL readings were measured at the 5 sites after the 6th & 7th removals.
RESULTS. After the 7th removal, the mean TEWL value for S1 was significantly higher (p< 0.05) than the other 4 sites, which was expected as this site was exposed to aggressive adhesive. The mean TEWL values for S4 & S5 on the opposite side of the abdomen were not statistically different, demonstrating that distance from vertical midline did not have an impact on TEWL when the formulations were equivalent. Interestingly, the mean TEWL value at S2 (gentler adhesive) was significantly higher than the bilaterally symmetrical S4 site (p< 0.05), despite being the same formulation & their equal distances from the midline. Distance from the site treated with the aggressive formulation A at S1 was the only identified difference between S2 & S4, suggesting that proximity to the injury caused by the aggressive formulation led to a gradient of greater TEWL in the adjacent sites treated with the gentler formulation.
CONCLUSIONS. Addressing the study’s hypothesis of bilaterally symmetrical injury responses was not possible, due to the finding that proximity to the injury caused by an aggressive barrier formulation influenced nearby TEWL readings, revealing that acute skin stripping injuries cause skin barrier disruption that extends beyond the point of injury. Further research is needed identify the cause of this gradient effect & the implication of this effect on study designs comparing adhesives within an individual subject.
P42.
P43.
P44.
Atopic dermatitis (AD) is a skin disease characterized by dry, itchy, and inflamed skin. Ultraviolet (UV)-free light therapy could be considered as a treatment of AD when medication is not effective and UV is considered harmful to the skin. UV-free light therapy is reported to be effective even when the light is irradiated to the normal skin far from the AD-affected sites; however, the mechanisms underlying this indirect effect remain unclear. We investigated the changes that occur with improvement in AD by indirect irradiation using UV-free light, with a focus on cytokine changes.
This interventional pre-post study enrolled five non-AD individuals (one male and four female, aged 21–40) and four AD patients (one male and three female, aged 21–48) after providing written informed consent. The intervention involved exposing the soles of the feet to UV-free light for 15 min three times weekly for six weeks. The Patient-Oriented Eczema Measure (POEM) was used to assess AD during intervention. We also collected systemic proteins from the inner side of the forearm using a skin blotting method, which can noninvasively capture circulating proteins through the skin, pre- and post-intervention. Cytokine levels in the collected samples were measured using a human cytokine array kit. This study was approved by the medical ethics committee of the university where the study was conducted (approval No. 2023-153-3).
Of the four participants with AD, two showed improved POEM scores (from 19 to 16 and 10 to 5, respectively), whereas the other two showed either no change (3 to 2 in POEM) or deterioration (6 to 12 in POEM). The cytokine profiles in AD revealed 15 upregulated and 19 downregulated cytokines. Among them, T-helper cells regulators (such as macrophage inflammatory protein (MIP)-3?, insulin-like growth factor (IGF)-1, IGF binding protein (IGFBP)-3, and IGFBP-4) and responders (including interleukin (IL)-5, IL-12, and IL-13) underwent changes due to UV-free irradiation.
In summary, our skin blot examination results revealed changes in T cell-related cytokines (MIP-3?, IGF-1, IGFBP-3, IGFBP-4, IL-5, IL-12, and IL-13) following irradiation of unaffected skin with UV-free light in AD patients.
P45.
The purpose of this study was to determine the sensitivity and specificity of a polyurethane shape memory polymer with bacterial protease-sensitive peptides (PUR-PEP) towards bacteria. Additionally, we explore the incorporation of molecular force sensors known as spiropyrans (SP) into the polymer to improve visible surveillance of infected wounds.
Strained PUR-PEP samples (n=3) were incubated in mammalian enzymes (matrix metalloproteinase-1, trypsin, and lysozyme), and in bacterial enzymes (S. aureus V8 and beta-lactamase) at 37°C for 10 days. Sample dimensions were measured using digital calipers every 24hr, and recovery ratios were determined based on differences in length. Strained PUR-PEP samples (n=3) were also incubated in serial dilutions of S. aureus (107 to 109 colony forming units (CFUs)) in stasis buffer for 7 days at 37°C. Samples were imaged daily with a camera, and dimensions were quantified using ImageJ software. To enable color change with shape change, 2.5 g of polymer was dissolved in chloroform, and 1.25 mg of photochromic SP was added. The mixture was poured into a Teflon dish until solvent evaporated, and the resultant films were dried in a vacuum oven. Samples were cut from the films, heated to 100°C, strained lengthwise, and then cooled. Samples were then imaged on a fluorescence microscope using the green channel or irradiated using a UV lamp (?max= 365 nm) and imaged with a camera to assess color changes before and after straining.
Strained PUR-PEP samples underwent significant shape recovery (~55%) (p<0.05) in both mammalian and bacterial enzymes. The material also recovered in all tested concentrations of bacteria, and a one-way ANOVA showed no association between bacteria concentration and shape recovery (F (1,5) = 0.68, ns). The strained PUR with SP exhibited increased fluorescence and luminiscence when irradiated with a UV lamp.
PUR-PEP recovery in mammalian enzymes indicates that the material chemistry requires tuning to improve its specificity towards bacterial proteases. However, the material recovery in all concentrations indicated high sensitivity and the potential to be utilized in detecting low grade or early infections. The photochromic response visible by fluorescence microscopy was due to increased absorbance by SP upon straining the PUR films. These are promising results as SPs could be used as a sensor to visually indicate changes in the shape of our PUR wound dressings, providing easily detectable color-based surveillance of infection in wounds.
P46.
Background
Adipose tissue is considered the most accessible and optimal source of extracellular matrix (ECM) products in clinical settings. In our prior study, we evaluated the effectiveness of human adipose tissue-derived ECM (adECM) sheets as a wound dressing material. To enhance healing potential and cost-effectiveness, we modified adECM sheets by adjusting ECM concentration and incorporating crosslinked hyaluronic acid (HA) Adipose tissue was obtained from healthy donors, processed, and casted into ECM sheets.
Methods
Crosslinked HA was added to create ECM-HA sheets (Scaffiller, Medikan, Korea). In vitro analysis involved seeding adipose-derived stem cells (ASCs) onto porous ECM-HA sheets and evaluating cell survival rate and cytokine array after 3 days. In vivo efficacy was assessed by applying ECM-HA sheets to full-thickness wounds in a rat model, with HA-based dressing and adECM sheets as control groups. Re-epithelialization and collagen deposition were examined through histopathological examinations, while immunohistochemistry was used to assess CD31, alpha smooth muscle actin (?-SMA), and Tenascin C expression as contributing factors to wound healing.
Results
The extracted ECM components accounted for approximately 5% of the original tissue volume, with ECM-HA sheet production efficiency being six times higher than adECM sheet. In vitro analysis revealed favorable ASC survival rates and increased angiogenetic and bioactive cytokine levels in ECM-HA sheet. Macroscopic evaluation showed enhanced healing rates, while histological analysis demonstrated improved epithelialization, thicker dermis, increased collagen deposition, and enhanced vascularity in the ECM-HA group. Notably, decreased ?-SMA expression and increased Tenascin C expression were observed in the ECM-HA group.
Conclusion
Our study successfully fabricated ECM-HA sheets incorporating adECM and HA, resulting in improved material stability, cost-effectiveness. ECM-HA sheets exhibited increased growth factor production, improved wound healing rates, collagen deposition, angiogenesis, and reduced myofibroblast activity. ECM-HA sheets hold promise as scaffolds for adipose-derived stem cells,
showcasing significant therapeutic potential for wound healing applications.
P47.
Use of Polyvinyl alcohol has been widely used in the chronic wound care space for many years. The role and function of the foam has been utilized for exudate management and antimicrobial barriers as both primary and secondary dressings for extracellular matrices and even in cases with NPWT. This study specifically looked at the feasability of using PVA foam for debridement purposes, in cases where all subjects could not undergo surgical excisional debridement. The study was conducted under an IRB review with the single site investigator. 20 subjects were enrolled for the clinical study. The PVA foam was applied weekly for 4 weeks duration as the primary dressing after saturation with sterile saline and a sterile dry secondary bandage. Surface area wound measurements were conducted using the Moleculight i:X device with documentation of reduction of bacterial immunoflorescence via wound photography. Findings showed that after 4 weeks, average wound surface area reduced approximately 54% from initial measurements and bacterial fluorescence was absent by week 4 in all subjects. These findings show that in patients with chronic lower extremity wounds that cannot tolerate surgical sharp debridement, the use of PVA foam can be an adequate adjunct for mechanical debridement modality as well as providing the patient an adequate anitmicrobial dressing.
P48.
P49.
Background: Pressure ulcers (PU) are injuries to the skin and underlying tissue that can have significant morbidity with the presence of complications such as dehiscence and necrosis. ClimateCare® is a mattress coverlet system that aims to maintain optimal skin moisture, temperature, and humidity levels at the interface between the patient and the surface to mitigate pressure ulcer risk factors. The objective of this study is to evaluate the effectiveness of ClimateCare® in improving wound outcomes and minimizing complications of pressure ulcers.
Methods: Patients with a stage III/IV pressure ulcer admitted for surgical closure were included in the randomized-controlled trial. All patients received the Fluid Immersion Simulation system (FIS), either with or without the ClimateCare® treatment based on a convenience sampling method. The subjects were monitored for 14 days post-closure (POD-14) for assessment of wound status and complications, including moisture, maceration, drainage, dehiscence, epidermolysis, necrosis, and demarcation.
Results: A total of 32 patients completed the study, where 18 patients received the ClimateCare® treatment and 14 patients did not. In the control group, 71% of patients had complications while 17% had complications in the ClimateCare® group (P=.001). In addition, 33% of patients without the ClimateCare® had open wounds, while no patients who received ClimateCare® treatment had open wounds (P=.011). Patient acceptability regarding treatment comfort, difficulty with mobilization, and pain at surgical site were not significantly different between ClimateCare® and control groups.
Conclusion: Our findings suggest that the ClimateCare® treatment in conjunction with the FIS may be effective in decreasing risk of postoperative complications and emphasize the importance of moisture control and pressure offloading in patients. Future studies should be conducted to characterize the effects of ClimateCare® in minimizing the risk of complications following wound closure.
P50.
P51.
P52.
Purpose: Pain management in burn treatment is important in improving wound healing and quality of life. Ibuprofen is a proven pain relieving agent in patients with partial thickness burn by intraveous injection. The purpose of this study is to evaluate the efficacy of Biatain Ibu® (polyurethane foam containing ibuprofen) in pain control for outpatients with partial thickness burns.
Methods: A prospective randomized clinical trial was performed in outpatients with partial thickness burn from August 1, 2017 to July 31, 2018. Acute pain, chronic pain, complications, days for re-epithelialization and patient’s satisfaction were compared between Biatain Ibu® and Biatain® groups.
Results: A total of 20 patients (Biatain Ibu®, n=10; Biatain®, n=10) were assessed in the trial. On Burn days 3, 5, 7, 11, 13, and 15, the acute pain levels were significantly lower in the Biatain Ibu® group than in the Biatain® group. Complications, chronic pain levels and days for re-epithelialization were not significantly different between the two groups. Patient’s satisfaction was not statistically significant but was higher in the Biatain Ibu® group.
Conclusion: Biatain Ibu® is effective in relieving pain in outpatients with partial thickness burn without decreasing patient satisfaction, wound healing ability or developing any complications.
P53.
Background: The purpose of this study is to evaluate the in vivo effects of MR-409, an agonistic analog of growth hormone releasing hormone (GHRH), on wound healing in the aged murine model. Given the rapidly expanding elderly population globally, and the high mortality associated with chronic wounds in this population, effective and innovative approaches to wound healing are necessary. Our preliminary data revealed that MR-409 synthetic GHRH analogue fosters senescent fibroblast survival, proliferation, mobility, and collagen synthesis. To corroborate these in vitro findings and offer more clinically contextualized evidence of these effects, we tested the effect of GHRH agonist MR-409 on wound healing in the aged murine model.
Methods: Thirty 78-week-old male C57/BL6 mice were separated into three treatment groups; ten mice per group in each of three groups were subjected to 8 mm skin punch biopsies and the responses to topical application of 1 痢/day (low-dose) or 10 痢 /day (high dose) of MR-409 were observed daily. Histologic analysis included aSMA staining, and photographs were taken on days 0, 4, 8 and 12.
Results: Results revealed enhanced wound healing with both low and high doses of MR-409 when compared to control group (p<0.0001). The greatest differences appeared as early as day 4. Enhanced wound healing was supported by histologic analyses of the wounds which showed decreased fibrosis in treated groups as well as evidence of enhanced wound contraction necessary for wound closure.
Conclusion: These results suggest that MR-409 synthetic GHRH analogue accelerates wound healing in a dose-dependent manner on aged skin that otherwise exhibits delayed healing, likely through the differentiation of fibroblasts into contractile myofibroblasts that approximate the wound.
P54.
A key cause of delayed healing in chronic wounds is the impaired cell migration due to systemic illnesses and advanced age. The current clinical care does not specifically address this impairment. Electrotaxis is the directional and accelerated cell migration guided by a direct current electric field (DC EF). Electrotaxis shows good efficacy in in vitro cell migration. But its in vivo efficacy is limited due to the difficulty in safely applying the EF strength typically used in in vitro studies (200 mV/mm) to in vivo tissues. Tissue damage can be caused by electrochemical reaction (ECR)-induced pH/temperature changes at high EF strengths. We developed a novel hydrogel ionic circuit (HIC) electrode to minimize pH/temperature changes when applying high-strength DC EFs. Our goal here was to determine the safety and in vitro electrotaxis efficacy of HIC electrodes when applying 200 mV/mm and higher DC EFs.
A HIC electrode consists of a carbon electrode inserted in a chamber filled with a saturated phosphate salt solution to absorb ECR-induced pH/temperature changes. The chamber is separated from the skin by a polyethylene glycol hydrogel, which prevents high-concentration phosphate salt ions from diffusing into the tissue. To evaluate the safety, 3 DC EF strengths (200, 400, and 800 mV/mm) were applied to pig skin for 5 hrs. Skin pH and temperature were measured right after EF application. An in vitro electrotaxis setup and HaCaT cells were used to test the electrotaxis efficacy. 200, 400, and 800 mV/mm were applied for 5 hrs. The directedness and projected migration speed along the EF direction of HaCaT were calculated. Directedness is a measure of cell migration direction, which is the cosine of the angle between the migration and the EF vectors. 3 repeats were used for safety experiments. 100 cells were analyzed in each migration experiment.
At all 3 DC EFs tested, HIC electrodes maintained a safe skin temperature below 42.8蚓 and a safe skin pH between 5.9 and 6.9. But a conventional carbon electrode increased the skin temperature to 43.9蚓, 49.7蚓, and 53.0蚓 at 200, 400, and 800 mV/mm, respectively. It changed the skin pH to 4.0(anode)/10.7(cathode) and 2.4(anode)/13.1(cathode) at 400 and 800 mV/mm, respectively. These pH/temperature changes can cause skin damage. At 200 mV/mm, HIC electrodes achieved similar directedness (0.67) and projected speed (11.1 痠/hr) as conventional carbon electrodes. At higher DC EFs, HIC electrodes significantly (P<0.05) increased the directedness to 0.90 and 0.95 and the projected speed to 33.2 and 61.8 痠/hr at 400 and 800 mV/mm, respectively.
In summary, we showed the ex vivo safety of HIC electrodes when applying 200 mV/mm and higher DC EF to skin tissues. We showed that high-strength DC EFs applied by HIC electrodes enhanced the directedness and projected migration speed of HaCaT cells compared to 200 mV/mm DC EF.
P55.
Introduction:
Total joint arthroplasty, including total hip arthroplasty and knee arthroplasty is of the most successful and reliable procedures in orthopedic surgery to restore function and alleviate pain. As orthopedic surgery in general has evolved to more patient centric and often done in the outpatient setting, so too have total hip and total knee replacements.
Delayed wound healing and wound infection continue to be one of the most common complications often with devastating effects, including repeat surgery and removal of the prosthesis. To improve the wound environment and promote healing, negative pressure dressings have been developed in recent years. The PICO system is unique in that it uses a highly absorbent sponge instead of a separate canister, and it is a disposable item.
This paper outlines a retrospective review of 100 consecutive same-day discharge total hip and total knee patients specifically to review delayed wound healing, wound infections and repeat surgery with all patients using the negative pressure PICO dressing postoperatively.
Methods:
Between October 5, 2021, and July 19, 2022, 100 same-day discharge total joints were performed consisting of 68 total knee replacements (TKA) and 32 total hip replacements (THA). There were 41 men and 59 women, with an average age of 62 (range 41-77) at the time of surgery. Eighty one percent of the patients had at least one medical comorbidity including hypertension (57%), diabetes mellitus (20%), coronary artery disease (6%), sleep apnea (5%) and renal disease (3%). All patients received the PICO dressing postoperatively. The hip replacement patients had it applied immediately after wound closure on the day of surgery. The knee replacement patients had their PICO applied on POD #1 during the first physical therapy appointment.
Results:
There was a 2% readmission rate during the 90-day postoperative period. One patient was admitted on POD #5 for gastritis and dehydration. The other patient was readmitted on POD #11 for weakness and anemia, work-up revealed bleeding from a GIST tumor which was resected without complication. There were no cases of DVT, PE, pneumonia or UTI. The mortality rate was 0%.
With this protocol, there were zero wound related issues. Specifically, no patient developed delayed wound healing, dehiscence or post-operative wound infection. There were no repeat surgeries in this cohort for wound related issues.
Conclusion:
Wound related issues continue to be one of the most common complications leading to more frequent visits, repeat procedures and patient dissatisfaction. The PICO dressing is ideal for the outpatient total joint setting where patient self-care is more common until the first follow up. In this series of 100 same day discharge patients, the PICO dressing proved to be beneficial with no wound related issues or repeat procedures and high level of patient satisfaction.
P56.
Introduction: The healthcare costs associated with treatment of chronic and burn wounds exceeds $25 billion annually in the US. Here we report the evaluation of a synthetic matrix, made of polyvinyl alcohol with a polymeric multilayer coating impregnated with silver and gallium that together kill biofilm bacteria, in healing of full thickness porcine burn wounds. The matrix has been shown to kill > 4 Log10 CFUs of clinically relevant planktonic and single-/multispecies biofilm bacteria (reported elsewhere).
Method: 20 full thickness burn wounds of 2 cm diameter were created on the back of 3 pigs using heated brass rod following a published method (Telgenhoff et al. 2007). Post burn, the wounds were excised and ten wounds on either side of the spine on each animal were treated with/without the matrix and wrapped with a protective Curad pad and ELASTIKON to secure the dressings. The dressings were reapplied on days 2, 4, 7, 10, 14 and 21. On days 0, 3, 7 and 28 blood samples were collected for complete blood count and quantification of silver and gallium in the blood plasma by inductively coupled plasma – mass spectrometry (ICP-MS). Samples for histology were collected on Days 7 and 28. After euthanasia, gross necropsy of all major organs were performed.
Results: Macroscopically and microscopically, wound healing followed the normal progression at all intervals and the wounds were healed completely by day 28. No major differences in the average scores for wound healing parameters — including granulation tissue, erythema, edema and re-epithelialization — at 7 and 28 days of treatment was observed. Histology analysis showed similar to near identical healing response scores at days 7 and 28. The matrix was classified as slight irritant when compared to Curad pads (control) at day 28, however this did not appear to affect wound healing, thus showing that the matrix is safe for use in full thickness burn wounds. Furthermore, the levels of silver and gallium in blood plasma assessed by ICP-MS were found to be below the limit of detection (0.5 ppb), thus confirming that there was no systemic absorption of silver or gallium during the 28-day healing period from the repeated topical applications of the matrix.
Conclusion: The antibiofilm silver/gallium matrix did not impair the healing of full thickness thermal burn wounds in a preclinical porcine model, exhibiting a high potential for clinical use.
P57.
Introduction: The healthcare costs associated with treatment of chronic and burn wounds exceeds $25 billion annually in the US. Here we report the evaluation of a synthetic matrix, made of polyvinyl alcohol with a polymeric multilayer coating impregnated with silver and gallium that together kill biofilm bacteria, in healing of full thickness porcine burn wounds. The matrix has been shown to kill > 4 Log10 CFUs of clinically relevant planktonic and single-/multispecies biofilm bacteria (reported elsewhere).
Method: 20 full thickness burn wounds of 2 cm diameter were created on the back of 3 pigs using heated brass rod following a published method (Telgenhoff et al. 2007). Post burn, the wounds were excised and ten wounds on either side of the spine on each animal were treated with/without the matrix and wrapped with a protective Curad pad and ELASTIKON to secure the dressings. The dressings were reapplied on days 2, 4, 7, 10, 14 and 21. On days 0, 3, 7 and 28 blood samples were collected for complete blood count and quantification of silver and gallium in the blood plasma by inductively coupled plasma – mass spectrometry (ICP-MS). Samples for histology were collected on Days 7 and 28. After euthanasia, gross necropsy of all major organs were performed.
Results: Macroscopically and microscopically, wound healing followed the normal progression at all intervals and the wounds were healed completely by day 28. No major differences in the average scores for wound healing parameters — including granulation tissue, erythema, edema and re-epithelialization — at 7 and 28 days of treatment was observed. Histology analysis showed similar to near identical healing response scores at days 7 and 28. The matrix was classified as slight irritant when compared to Curad pads (control) at day 28, however this did not appear to affect wound healing, thus showing that the matrix is safe for use in full thickness burn wounds. Furthermore, the levels of silver and gallium in blood plasma assessed by ICP-MS were found to be below the limit of detection (0.5 ppb), thus confirming that there was no systemic absorption of silver or gallium during the 28-day healing period from the repeated topical applications of the matrix.
Conclusion: The antibiofilm silver/gallium matrix did not impair the healing of full thickness thermal burn wounds in a preclinical porcine model, exhibiting a high potential for clinical use.
P58.
Our skin is home to a diverse community of commensal microorganisms that are integral to cutaneous function. Microbial dysbiosis and barrier perturbation increase the risk of local and systemic infection. Staphylococcus aureus is particularly problematic with high levels of antimicrobial resistance and direct association with poor healing outcome. Thus, innovative approaches are needed to selectively kill skin pathogens, such as S. aureus, without harming the resident microbiota. Bacteriophage-derived cell wall-lytic enzymes, known as endolysins, are emerging as promising alternatives to traditional antibiotics. However, their efficacy is seldom assessed in models harbouring a complex microbiome due to the historic challenges associated with bacterial sampling, characterisation and profiling. We thus developed a novel pipeline, combining long-read metagenomic sequencing and RNA-sequencing, to provide the first demonstration that endolysin selectively inhibits endogenous S. aureus in vivo, leading to higher microbial diversity and promoting multiple aspects of wound repair. Further mechanistic evaluation confirmed the importance of microbiome modulation for effective healing in human skin. Together, these findings provide new insight into the role of Staphylococcus in healing pathology, and support further therapeutic development of S. aureus-targeted endolysins for clinical management of skin and wound infections.
P59.
Introduction: Biofilms are implicated in delayed healing in chronic wounds, however there is no commercially available topical formulation effective in dispersal of biofilms in wounds. Here we report the evaluation of antimicrobial, antimicrobial barrier and antibiofilm performance of a synthetic matrix, made of polyvinyl alcohol with a polymeric multilayer coating impregnated with silver and gallium, both in vitro and in vivo.
Methods: Antimicrobial performance of the matrix over 24 and 72 h was tested against 8 clinically relevant microbes (K. pneumoniae, E. coli, C. albicans, C. tropicalis, MRSA, S. aureus, P. aeruginosa, and E. faecalis) per ISO 22196. Its antimicrobial barrier performance was evaluated by pipetting 10 µL of bacterial inoculum of P. aeruginosa, A. baumannii or K. pneumoniae on the matrix placed on an agar plate and incubating at 37 ± 2 °C for 3 days and quantifying the CFU subsequently.
To evaluate the antibiofilm performance in vitro, robust biofilms containing 108 CFU of A. baumannii or K. pneumoniae were established on gauze specimens over 48 h and rinsed with saline to remove planktonic bacteria. Moist biofilm specimens were then treated with a single application the matrix for 24 h, and the CFUs were determined relative to no-treatment controls. In vivo assessment was performed by transplanting preestablished biofilm in 1 cm dia. full thickness porcine wounds by placing the gauze specimens supporting 108 CFU P. aeruginosa biofilms for 24 h. Afterwards, the gauze specimens were removed and wounds were treated with the matrix once daily for two days. On day 3, biopsies of all wounds were minced and CFUs were determined relative to no-treatment control.
All assays were carried out with at least three replicates for each sample. Groups were compared using a Student’s t test at P < 0.05.
Results: The matrix killed > 4 Log10 CFUs of all microbes tested per ISO 22196, thus confirming its antimicrobial activity against planktonic bacteria. It also killed bacteria on its surface and prevented the breakthrough of microbes over 72 h thereby demonstrating its ability to serve as an antimicrobial barrier. > 4 and 1.5 Log10 CFU reduction of A. baumannii and K. pneumoniae biofilms bacteria was achieved in vitro over 24 h with a single application of the matrix, and the matrix was killed 1.5 Log10 CFU of P. aeruginosa biofilm bacteria in vivo, thus establishing its antibiofilm performance.
Conclusion: The silver/gallium matrix is effective in killing both planktonic and biofilm bacteria and is thus suitable for assessment in the treatment of biofilms in chronic wounds.
P60.
Autologous bone grafts are widely used to repair bone defects, such as craniofacial abnormalities. However, procedures involving alveolar bone grafts are invasive and there is risk for donor site infection and morbidity. Bone tissue engineering, which incorporates stem cells, scaffolds, and biological factors, is a promising alternative to current repair methods for cleft palate and other bone defects. In our study, we assess the impact of several scaffolds, including collage sponge implant, collagen gel with superficial silicone sheet, and collagen gel only on bone regeneration in a calvarial defect. Natural polymers, such as collagen, can be a useful material in bone tissue engineering. At 5 weeks of age, we created a 3 mm diameter calvarial defect in the parietal bone of mice. We implanted a collagen sponge pre-loaded with 20 microliters of PBS, a collagen gel with a silicone sheet, collagen gel only, or no intervention at all (control). At 4 or 12 weeks, we harvested the mice calvaria for analysis. We performed 3D-reconstruction volumetric analysis using the Amira software. For immunostaining, we cryosectioned the bone samples at a thickness of 30 um. We used immunostaining to characterize the components of the osteoconductive environment. At 4 and 12 weeks, collagen gel implant with overlying silicone sheet had the highest percent of bone growth in the defect, 24.7% and 30.9%, respectively. Collagen gel and collagen sponge implants had similar percentages of bone growth at 12 weeks, 25%, and 25.6%, respectively. All scaffold implants had a higher percentage of bone growth in the defect compared to the control condition (2% at 4 weeks and 7.8% at 12 weeks). Immunostaining analysis for the collagen gel and silicone sheet implants showed endomucin and CD31 staining for blood vessels within the fibrous bridge that connects the newly generated bone in the defect area to the surrounding intact bone. We also observed endomucin and CD31 signal in the periosteum at the edge of the defect and surrounding the new bone marrow. The superior bone growth at 4 and 12 weeks in the collagen gel and silicone sheet condition suggests that these materials foster an enhanced osteoconductive environment. The prominent presence of endomucin and CD31 staining marks neovascularization, a vital component for sustainable bone regeneration, and continuity between new and intact bone, across the fibrous bridge and into the intact bone. In the future, understanding the mechanisms involved in bone regeneration, and identifying key cells, can help optimize scaffold treatment options for bone defects for applications in bone tissue engineering procedures in pediatric cases, such as cleft lip and palate disorders.
P61.
Purpose: The goal of this study was to develop a benchtop vaginal model to test self-fitting polymer stents for mitigating vaginal fibrosis.
Methods: We used an emulsion templating approach to fabricate a thermoresponsive shape memory polymer (SMP) foam from poly(e-caprolactone). To expedite the design of the stent geometry and provide better predictions of performance in vivo, a custom benchtop pelvic model was developed to simulate vaginal anatomy, temperatures, and pressures. Clinical MRI images were used to construct a silicone vaginal canal from EcoFlex. The canal was encased in an acrylic pressure chamber to simulate pelvic floor contractions. Physiological temperatures were replicated by wrapping heating tape (BriskHeat, 144W) around the pressure chamber. Model parameters were validated against clinically reported values. We also tested the usefulness of our testing apparatus in iterative device design by modeling stent deployment and retention. Stent expansion and deformation was visualized using a hysteroscope (Endosee) placed near the introitus of the model.
Results: Temperature readings were taken at three locations within the model (cervical, central, and introitus regions) in triplicate and confirmed to be within physiological ranges (36°C ± 1°C). A perineometer (MizCure, OWOMED) was used to assess the radial forces within the model according to a previously established protocol.1 The model pressures were measured to be within physiological parameters (19 mmHg ± 1 mmHg). A crimped SMP vaginal stent expanded to walls of the canal (~70% increase in cross-sectional area) in <5 minutes after irrigation with warm water (~45°C). The stent’s cross-sectional area decreased by <1% in response to physiological pressure. Stent diameter exhibited ~8% decrease along the anterior-posterior dimension, with a corresponding 8% increase distally.
Conclusion: Overall, these results demonstrate the potential of this newly designed SMP foam for use as a self-fitting vaginal stent and provide a benchtop pelvic model for guiding the design of gynecological devices.
References:
1. Abe-Takahashi, Y.; Kitta, T.; Ouchi, M.; Okayauchi, M.; Chiba, H.; Higuchi, M.; Togo, M.; Shinohara, N., Reliability and validity of pelvic floor muscle strength assessment using the MizCure perineometer. BMC Women’s Health 2020, 20 (1), 257.
P62.
Introduction
Copper-Iodine Complex Solution (CICS) is an FDA 510(k) cleared medical device as a wound irrigation system. This unique complex has the capacity to neutralize a broad number of pathogens such as bacteria, viruses, yeast, and fungi without evoking bacterial resistance. Free Iodine (I2) is a recognized powerful and broad-spectrum antimicrobial with no known resistance by exhibiting multi-mechanisms of action, highlighting: (i) penetration into the cell wall of the microorganism, causing blocking of the hydrogen bonds which results in damage to the phospholipid cell membrane, (ii) and damage and denaturing of the essential proteins, nucleotides and fatty acids by binding to thiol and amine groups, leading to rapid cell death. Free iodine acts as a preservative agent that helps to remove contamination within the CICS for effective wound cleaning. CICS has been proven to be non-cytotoxic, non-pyrogenic, non-irritating, and non-sensitizing to dermal tissue.
The purpose of this study is to quantitatively evaluate the effect of CICS on biofilm in a porcine model and commonly used implant material substrates (silicone and titanium alloy).
Materials and Methods
Two implant materials were used in this study to grow biofilms, silicone, and titanium alloy substrates. Three independent time trials were conducted, 5h, 24h, and 72h. Data was analyzed with one-way Anova and Tukey post-hoc tests. p-value: <0.05. This In vitro biofilm test was conducted by the Center for Biofilm Engineering at Montana State University.
Results
1. Efficacy of CICS against S. epidermidis mature biofilms on silicone substrate
Results: 1.7 log reduction at 30 min, 4.7 log reduction at 2 hours, 6.6 log reduction at 5 hours and 7.0 log reduction at 24h and 72h. No colonies observed at 24h and 72h.
No statistical difference was observed between 5h, 24h and 72h kill rates.
2. Efficacy of Bioclynse against S. aureus mature biofilms on titanium alloy substrate
Results: 0.6 log reduction at 5 min, 1.8 log reduction at 0.5 hours, 4.7 log reduction at 2 hours and 7.5 log reduction at 24h. No colonies were observed at 24h.
GLP in vivo study (porcine model) to assess the anti-biofilm and antimicrobial activity.
Results: CICS reduced total bacteria in the biofilm by 2.0 – 2.5 log CFUs compared to initial inoculation level.
Conclusion
Copper-Iodine Complex Solution has been shown to generate a significant log reduction in the growth of both Staph aureus and staph epidermidis biofilms grown on silicon and titanium implant materials. Biofilms were also reduced in a in vivo wound porcine model. Further studies are needed to show that this can help to prevent and to treat infected implants in humans.
P63.
Introduction
Copper-Iodine Complex Solution (CICS) is an FDA 510(k) cleared medical device as a wound irrigation system. CICS is indicated in wound management, cleansing, irrigating, moisturizing, and debriding of acute and chronic dermal lesions that are partial or full thickness wounds.
This unique complex has the capacity to neutralize a broad number of pathogens such as bacteria, viruses, yeast, and fungi without evoking bacterial resistance1-4.
CICS has been proven to be non-cytotoxic, non-pyrogenic, non-irritating, and non-sensitizing to dermal tissue12-16.
The purpose of this study is to quantitatively evaluate the effect of Copper-Iodine Complex Solution on bacteria, yeast, fungi, and SARS-CoV-2 virus in an in vitro model.
Materials and Methods
Trial #1 – demonstrates antimicrobial efficacy testing as a preservative in solution using five common organisms at 14 and 28 days.
Trial #2 – addresses time – kill data against 15 clinically relevant pathogens.
Trial #3 – addresses persistent antimicrobial efficacy after re-inoculation using 3 different time points.
Trial #4 – addresses and validates the efficacy of CICS against SARS-CoV-2.
Results
The results of all 4 independent in vitro studies will be reviewed in detail. There is significant log reduction of bacteria, yeast, and fungi in all invitro evaluation. This is also evident in a variety of time periods that the organisms are exposed to CICS with the associated log reductions of clinical significance. Long-lasting CICS efficacy against ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter sp) and Candida albicans and Candida tropicalis has been demonstrated up to 3 days The final study shows the results of CICS against SARS-CoV-2 virus. After incubation with undiluted CICS for 10 minutes, viral titers dropped by 2 logs (one tailed t-test p-value = 0.0140). After incubation with undiluted CICS for either 30 minutes or 60 minutes, viral titers dropped below the limit of detection (< 75 TCID50 per ml).
Conclusion
Copper-Iodine Complex Solution has been shown to create a significant log reduction with kill rate in multiple gram positive and gram-negative bacteria, yeast, and fungi. Additionally, CICS has been shown to be effective against SARS-CoV-2 virus. Further studies are needed to support these findings.
P64.
Introduction
All common negative pressure wound therapy (NPWT) systems include a filler material usually foam or gauze at the wound/device interface. The filler material increases airflow and thus increases the required pump capacity that can cause patient discomfort or even ischemia in wounds with compromised vascularity. In addition, foam or gauze may fragment and become colonized with bacteria over time. To mitigate these, negative aspects, we have developed a new impermeable single layer component membrane dressing to deliver NPWT that does not need a foam or gauze to function. The purpose of this study is to introduce Negative Pressure – Platform Wound Device (NP-PWD).
Materials and Methods
The NP-PWD is a transparent, single component dressing that consists of an impermeable polyurethane membrane. It has a permeable adhesive base which is attached to the perimeter of the wound, enabling fast Band-Aid-like application. The suction pump is connected to the underside of the membrane with tubing. The inner surface of the PWD contains pyramid-like structures protruding toward the wound. Once the suction pump is turned on and the desired negative pressure is achieved, the embossed membrane is pulled into contact with the entire surface area of the wound and the space between the pyramids is providing channels for even distribution of negative pressure as well as for exudate removal. Folds in the membrane provide secondary channels for negative pressure and fluid removal. The NP-PWD has been extensively validated in preclinical large animal models as well as in clinical case series.
Results
The results have demonstrated that the NP-PWD can function effectively at lower negative pressures (-80 mmHg and -50 mmHg) promoting healing, reducing tissue necrosis, inflammation and bacterial burden in the wounds. Importantly, when compared to the conventional devices, with foam or gauze, no differences were observed. Clinical studies have reported that patients tolerate the NP-PWD well. In addition, the possibility to monitor the wound without dressing removal has proven to be beneficial in a clinical setting.
Conclusions
The NP-PWD is a simplified, single component NPWT system eliminating the use of the filler material that commonly causes challenges during treatment.
P65.
Pathological biofilm formation is a major issue that restricts the functional use of implants and scaffolds in wound healing, resulting in delayed healing, chronic infections and impaired tissue regeneration. Embedding nanoparticles directly into the wound-bed could be a viable strategy, but present the drawback of quick diffusion. It also doesn’t provide enough mechanical support for the healing tissue. A solution to this problem would involve embedding the particles inside a wound dressing biomaterial. Introducing antibacterial nanoparticles into woven natural biomaterials as biofabrics would help retain antibacterial activity while providing mechanical support. Here we propose to develop a controlled release antibacterial biofabric produced by electrospinning polymethyl methacrylate (PMMA) as the base material, silk fibroin (SF) as a component to provide mechanical strength, and cationic hyperbranched polyethyleneimine (PEI) to provide antibacterial properties. We propose the antibacterial biofabrics could be a valuable tool to treat chronic wounds as well as coatings for implants (i.e. cardiac pacemakers) that potentially cause infections.
Methods
SF Regeneration: Silkworm cocoons are boiled to separate fibroin yarns. Silk fibroin is solubilized in LiBr solution followed by dialysis to achieve SF solubility in water. Electrospinning: In order to make biofabrics, PMMA, SF, and/or PEI were combined in dimethylformamide (DMF) and transferred into an electrospinning setup. Polymer solvent was fed at 1.4 ml/hr at 20 kV from 20 cm away from the collector until a thick nanofiber biofabric was developed. Nanoparticle Development: A 4% w/v SF solution was added dropwise to acetone and sonicated for 30. For SF|PEI particles, 1% w/v PEI was added to the same process. The resulting solution was left to stir overnight and the remaining dried particles were crushed with a mortar and pestle and set aside. Inhibition of bacterial growth in liquid medium: Three samples containing 5 mg of SF|PEI were prepared and placed in 5 ml of nutrient broth for an antibacterial assay, alongside samples of 5 mg SF particles in nutrient broth and nutrient broth alone. P. Aeruginosa was seeded into all vials, which were then incubated at 37°C, and the absorbance was measured using a spectrophotometer after 24 hours.
Results.
Preliminary P. aeruginosa growth assay showed not SF but SF-PEI nanoparticles were 96% effective in inhibiting bacterial growth. Current studies are ongoing in incorporating SF and PEI into PMMA to produce antibacterial biofabrics. The proposed fabrics will not only will provide controlled release of PEI into chronic p. aeruginosa infections but also will provide mechanical support via introduction of SF.
P66.
Purpose: To determine if there are differences in strain relief in sacral dressings under physiological loads. Background: Patients who must remain prone for long periods end up placing a high burden on the skin of the sacrum. A class of border dressings has been in use to mitigate the lateral strains on the sacrum while the patient shifts while the sacrum is under load. There a several “substantially equivalent” devices on the market, but their relative performance in strain mitigation is unknown.
Methods: A custom digital image correlation system with a bead-loaded silicone sheet was used to monitor the strains in the sheet under physiological loads (Mimura et al. 2009 WRR., 155 mmHg). A stepper motor was used to apply 216 N of external shear force in 0.625-mm steps for 40 steps. The 4 dressings were compared to no treatment in triplicate. An initial measurement of the maximum gross lateral strain was quantified in FIJI and compared by one-way ANOVA (a = 0.05) followed by a pairwise-Tukey HSD post-hoc test. Results: The mean of the dressings maximum strains were 0.0162, 0.0231, 0.0285, & 0.0267 (nil = 0.1206). The ANOVA revealed very significant differences (p = 1.09 x 10^-13). All dressings were very substantially better than Nil (p < 0.00009). The best performing dressing was better that all the rest (p < 0.0131). The second best was better than the remaining 2 (p < 0.049). Conclusions: We have found a means to compare regulatorily similar sacral dressings under physiological loads and find statistically significant differences in strain relief. Additional work continues to identify the pressure load at which performance among the dressings begins to differ.
P67.
Aim: In nasal bone fracture surgery, the post-operative packing material can be divided into conventional materials, such as Vaseline gauze that requires removal, and absorbable materials that is totally degraded and does not require removal. Nasopore, a biodegradable synthetic polyurethane foam, is the material mainly used as nasal dressing. Although it has no need for post-operative removal, it is soft and hydrates quickly, making it difficult to provide sufficient support to maintain the post-reduction status. The aim of this study is to introduce a novel method to improve durability of Nasopore with Proheal.
Method: Instead of packing Nasopore directly into the nasal cavity, we wrapped Nasopore with Proheal, which is a collagen wound dressing material. After reduction of the nasal bone, nasal cavity was packed with nasopore wrapped with proheal(Fig.2), while the non-fractured nasal cavity was packed with proheal rolled up only.
Results / Discussion: As Proheal help delay the hydration of Nasopore, it improves supportability and maintenance of Nasopore(Fig.4). Additionally, nasal mucosal healing was observed to be faster, indicating a potential positive impact of proheal on the healing process.
Conclusion: The proheal-wrapped nasopore provided sustained support and exhibited a longer-lasting property compared to nasopore alone. Moreover, it contributed to faster nasal mucosal healing. These findings suggest that the application of proheal-wrapped nasopore could be a superior choice in nasal bone fracture surgery, as it offers improved stability and facilitates a quicker recovery. Considering proheal-wrapped nasopore may lead to enhanced surgical outcomes and improved patient recovery.
P68.
P69.
P70.
Introduction
Our compound, PEG-BPEI, counteracts (i) pathogens, (ii) biofilms, and (iii) toxins using electrostatic binding with the anionic components of each target. This occurs simultaneously and independently; and these multi-factor benefits are unlikely to be found with other compounds. Our research team, funded by the NIH, Department of Defense, and the University of Oklahoma, has carried out a productive multi-site collaboration evaluating the ability of PEG-BPEI, and the bioactive moiety 600 Da BPEI, to disable antibiotic resistance mechanisms, neutralize endotoxins, and disperse biofilms – factors linked to the dysregulation of wound healing. Developing PEG-BPEI products requires a delivery strategy. Candidate materials for delivery are gels, creams, and foams that are well-known non-immunogenic biomaterials.
Product Development
PEG-BPEI also differs from existing technology because it is not a peptide and thus resists proteolysis, unlike cationic peptides and peptide mimetics susceptible to rapid proteolytic degradation and/or protein binding. PEG-BPEI is a hydrophilic molecule that is completely miscible with water. We have demonstrated the ability to formulate PEG-BPEI with gels, creams, and polymers. We have used PEGylation to reduce the in vivo toxicity while retaining activity. Importantly, we also reduce toxicity issues by using very-low molecular-weight BPEI (600 Da) rather than higher molecular-weight BPEI (over 25,000 Da).
Methods
PEG-BPEI is cationic and uses electrostatics for binding with anionic sites on Gram-positive and Gram-negative bacteria. PEG-BPEI and the bioactive moiety 600 Da BPEI, have broad-spectrum activity to counteract (1) antimicrobial resistance (AMR) caused by the Gram-negative LPS layer; (2) AMR caused by Gram-positive cell wall and teichoic acids (3) AMR caused by metallo-?-lactamases; (4) Release of pro-inflammatory cytokines in response to the Gram-negative pathogen associated molecular pattern molecules (PAMPs) LPS and peptidoglycan; (5) Release of pro-inflammatory cytokines in response to the Gram-positive PAMPs teichoic acids and peptidoglycan; and (6) Biofilms formed by Gram-negative pathogens; and (7) Biofilms formed by Gram-positive pathogens.
Results
Checkerboard assays using microtiter plates demonstrate the antibiotic properties. Growth curves demonstrate bacteriostatic effects. Scanning electron microscopy (SEM) was used to confirm that the combination treatment leads to abnormal morphology. Data collected with isothermal titration calorimetry and fluorescence spectroscopy demonstrate a mechanism of action. ELISA was used to neutralize endotoxins (LPS, LTA, peptidoglycan) that otherwise stimulate pattern recognition receptors, leading the release of pro-inflammatory cytokines. Additional data show that PEG-BPEI can be absorbed onto, and released from, drug-delivery systems.
P71.
Chronic wounds are a prevalent global health concern, annually affecting 6.5 million Americans with $25 billion burden on healthcare systems. Accurate and timely wound assessment is crucial for effective wound management, enabling clinicians to monitor healing progress, identify complications, and optimize treatment strategies. However, traditional wound assessment methods and manual measurements are often subjective, qualitative, time-consuming, and prone to errors, leading to suboptimal wound care outcomes and prolonged healing times. Artificial intelligence (AI) based wound assessment tools have emerged as promising solutions to address these challenges. These tools utilize machine learning algorithms like deep learning and convolutional neural networks to analyze wound images and provide objective, quantitative assessments of wound characteristics, such as wound area, tissue type, and healing status. A growing body of research has explored the development and application of AI-based wound assessment tools. The objective of this work is to review the current landscape of AI-based wound assessment tools and decision support systems, encompassing both smartphone apps and research papers, aiming at assessing their accuracy, identifying knowledge gaps, and informing future research directions in this field. We assessed performance metrics, input information, AI methods employed, accuracy & speed of assessment, level of user intervention, dataset size and quality, and clinical evaluation. We found that most of these studies focused on wound documentation and development of image-based wound area measurement algorithms like thresholding, while more recent studies focused on developing algorithms using convolutional neural network and region-based segmentation for tissue classification, with relatively small datasets ranging from 80 to 600 wound images. While most of the studies utilized wound pictures taken by smartphones, more recent publications focus on measuring the wound depths using RGB-D cameras and other medical imaging devices. A few works delved into developing decision support systems, aiming at providing clinicians with enhanced decision-making capabilities by leveraging AI algorithms to analyze complex wound data and offer personalized recommendations. Our findings also revealed that the current body of literature and existing applications suffer from the absence of reliable datasets, inaccurate measurements, and need for operator intervention. Additionally, there exists a knowledge gap in volumetric wound assessment and decision support systems. As the body of literature expands and technology progresses, there is a growing need for AI-based wound assessment tools to transition from research labs to clinical applications.
P72.
Methods:
Patient T is a 69-year-old male patient living at high elevation in Arizona who had developed a chronic diabetic venous wound on the lower leg. Despite being a professional trauma nurse in Emergency Room Medicine for over 45 years, persistent wound status for 12 months resulted in self-referred consideration of an antimicrobial hydrogel that has been shown to effect healing in diabetics (Figure 1). The nurse-patient self-administered hydrogel once weekly until healed. Despite achieving complete and cosmetic closure after 9 weeks, Patient T accidentally reopened the wound tripping which resulted in a new deep ulcer abrasion (Figure 2). The patient followed a similar mode of treatment with self-administered hydrogel once weekly for six weeks at which time the wound was completely healed. Both wounds were treated with use of novel anti-microbial hydrogel and healed completely with full closure and acceptable cosmesis despite diabetic status and 12 months of open wound.*
Results:
Patient T followed protocol for weekly administration of Floraseptic and documented the healing progress with weekly images. FloraSeptic contributed to the accelerated healing process in Patient T. All evidence of the diabetic venous ulcer wound showed closure by the end of the 30-day treatment period full closure of the wound signifying successful wound healing. (Figure 1) The second wound, or the reopened wound abrasion, showed similar closure in less than 2 months. Granulation tissue formation was observed within the first week of treatment, followed by a progressive reduction in wound size, improved tissue quality, and full closure, signifying successful wound healing. (Figure 2)
Conclusion:
The application of FloraSeptic led to expedited wound healing, with complete closure. One important differentiating facet of the application was treatment for a persistent, non-healing wound in a patient with diabetes over a relatively short course with no issues of delay, seeping, or need for antibiotics. FloraSeptic, a novel and innovative wound care product, appears to offer a promising solution for healthcare providers in the management of challenging venous ulcers even amidst the additional complication of diabetes. Developed with a botanical formulation to promote healing, Floraspetic provides antimicrobial protection, and sustains a balanced and optimized pH that supports epithelialization and wound closure during the healing process. Previous evaluations in spine surgery have demonstrated reduced surgical site infections and accelerated healing, while at the same time retaining normal skin pigmentation.1
References:
*FloraSeptic, BonePharm, LLC, Tampa, FL
[1] Spencer T, Gorinshteyn B, Ganey T. Efficacy and Safety of Berberex Wound Cleanser on Post-Operative Surgical Incisions. Clin Surg. 2016; 1: 1196.
P73.
P74.
Background: The need to optimize the use of electroceutical therapy for the site specific repair of chronic wounds has received tremendous attention in the last 20 years. Devices for chronic wound healing utilizing direct current, pulsed, or alternating electric current have been explored to stimulate the body’s cellular and molecular responses towards enhancing chronic wound healing, especially to bridge the persistent inflammatory phase associated with most chronic wounds which consequently delay the healing process.
Methods: This systematic review aimed to identify devices that utilize electrical stimulation to enhance chronic wound healing. This study followed the Preferred Reporting Item for Systematic Review and Meta-Analysis (PRISMA) checklist. A literature search was conducted on studies published from 2000 to 2023 using Google Scholar, PubMed and ScienceDirect with the following keywords: wearable devices used for wound healing, wearable technologies used in wound healing, bioelectronic devices for wound healing, electroceutical devices used for wound healing. Inclusion criteria for published articles considered are specific to electroceutical devices that harness electrical stimulation for chronic wound healing. Exclusion criteria used to screen articles include wearable devices for monitoring body physiological and biochemical markers, devices delivering medication for infection control, devices using other wound healing modalities without electro-stimulation, and wearable electroceutical devices for acute wound healing. Titles and abstracts were screened to avoid duplicity and included those only with clinical data relevant to this review.
Results: A literature search revealed a total of 2235 related articles that mention the use of electrical stimulation. Out of these, 29 utilize electrical stimulation to enhance wound healing. Present wearable technologies support the possibility of using electrical stimulation as a concurrent or supplementary therapy in the management of chronic wound healing by harnessing the body’s endogenous electric field generated by ions. However, there is no standardized protocol that compares these various modalities to point out the ideal technology needed for translation into clinical use.
Conclusion: Wearable devices utilize various electro-stimulation patterns which include direct, alternating, and pulsed electric currents to stimulate cells, endogenous electric fields, angiogenesis, and growth factors for accelerated healing. The ideal device design remains an active research field for biomedical engineers. The need for soft-flexible devices in clinically-relevant form factors with occlusive and transparent wound dressings are necessary for such technologies to serve as adjuvant or primary treatment modalities for chronic wound healing.
P75.
Introduction
This study sought to evaluate the evidence of a novel topical, non-biologic technology employed for wound bed preparation with respect to pH modulation and stabilization. Regenerative Debridement Therapy (RDT)is a topical liquid agent for healthcare practitioners in the debridement of wounds, burns, and surgical site infections.it removes necrotic tissue, destroys biofilm upon contact, and reduces proinflammatory markers that become unbalanced in chronic wounds.
The purpose of the study is to examine the effect of RDT on pH in the wound bed of chronic DFUs and VLUs.
Methods and Materials
Adult patients with chronic DFUs and VLUs were considered eligible. Primary endpoint was pH collection at baseline, directly post sharp debridement, 30-60 seconds after sharp debridement, day 1, day 7, and day 14. 28 patients in the RDT group and 5 controls in each the DFU and VLU groups. Wound volumes were measure at each visit. SOC for DFU was hydrogel dressing and offloading, VLU was an alginate dressing and compression. All DFUs were plantar Wagner grade 2 and VLUs were full thickness dermal wounds of the gator region.
Results
Table 1 – DFU patients
Table 2 – VLU patients
Table 3 – Percentage Volume Reduction – All patients
Table 4 – Percentage Volume Reduction – DFUs
Table 5 – Percentage Volume Reduction – VLUs
(all data is reviewed in the poster, as there are limitation due to abstract format)
Conclusion
There is a marked, extended reduction in wound bed pH with the use of Regenerative Debridement Therapy. The RDT allows the pH. to maintain physiologic normal dermal pH for 7 day and further. This is with one, 30-60 second application after sharp debridement. There is also accelerated wound closure as seen with PVR grafts. Further studies are warranted.
P76.
Background
Dermatomyositis (DM) is a rare inflammatory condition of the skin and muscle with a variety of clinical findings including characteristic skin presentations, calcium deposits, and concommitant cancer diagnoses. We share the case of a patient utilizing glucocorticoid treatment for end-stage DM and discuss the influence of disease and treatment that complicate wound management.
Case Presentation
A 60-year-old female presented to the wound clinic for slow healing hip and lower extremity wounds with signs of infection on both hip wounds despite negative cultures. She also exhibited extensive extremity and abdominal calcifications secondary to end-stage dermatomyositis and chronic daily glucocorticoid use of 7 years. She has a history of other immunosuppressive medications such as azathioprine, methotrexate, and infliximab injections in addition to history of previous sugrical debridement. Despite meeting clinical criteria for DM, she had normal JO-1, RNA Polymerase III IgG, and PM-Scl antibody levels found on testing. Multiple wounds were documented, with terribly slow healing courses, calcium deposits were drained in clinic, and finallly surgical debridement was successful.
Discussion
Dermatomyositis presents numerous challenges in management, particularly in advanced stages of the disease. This case highlights a notable manifestation of slow wound healing, emphasizing the complexities involved in the treatment approach. Evidence of vasculopathy in DM has been integral to this process leading to compromised blood flow. More specifically, DM patients often have decreased capillary network density. Changes on these fronts affect the proliferation and remodeling phases of healing in addition to the inflammatory process that is inherently dysregulated in DM.
In managing this end-stage dermatomyositis case, conventional therapeutic approaches involving corticosteroids were implemented and continue to be utilized with this patient today, the current standard of care. Bologics such as monoclonal antibodies (rituximab, infliximab) also used have shown to be well tolerated in paatients with dermatomyositis and polymyositis. Methotrexate, has also shown some efficacy. Azathioprine well targets the muscle involvement of DM, but there is limited literature suggesting efficacy addressing the cutaneous aspects of the disease.
Conclusion
In summary, this case report highlights the intricate challenges associated with managing end-stage dermatomyositis, notably emphasizing the complication of slow wound healing. Despite the efficacy of conventional treatments such as corticosteroids and adjunctive therapies like biologics and methotrexate, the persistent issue of impaired wound healing raises broader systemic implications of the disease.
A deeper understanding of the intricate vascular mechanisms could elucidate more targeted interventions.
P77.
Due to their similarity to human skin, pigs are increasingly used to study wound healing. Both pig and human skin have firm attachment, sparse hair coat, thick epidermis and dermis, no panniculus carnosus, and heal by re-epithelialization with minimal contraction.
Flow cytometry is a robust method to analyze the inflammatory milieu at the wound site. Although efforts have been made to optimize porcine skin digestion for flow cytometric analysis, it is currently not a common practice and there are no widely used protocols.
Our lab optimized a method to isolate single cells from porcine skin following excision injury using an enzymatic digestion that yield consistently robust single cell isolation with high viability. We also optimized reliable antibody panels, for the identification of granulocytes (CD45+2B2+), monocytes subsets (CD45+2B2-SLADR-CD14+CD16+/-), as well as M1 inflammatory (CD45+2B2-SLADR+CD80+) and M2 reparative (CD45+2B2-SLADR+CD163+) macrophages. Development of a reliable method to isolate single cells from porcine skin opens the door for studies to assess the cellular changes during porcine wound healing.
P78.
Veterans encounter formidable barriers in accessing essential wound care and managing chronic wounds, stemming from a multifaceted interaction of systemic, geographic, and psychological factors. Geographical disparities pose a significant challenge, as specialized wound care facilities are often concentrated in urban areas, leaving veterans in remote or rural locations with limited access. Veterans are also at increased risk of experiencing hurdles such as limited access to specialized wound care facilities, fragmented healthcare coordination, and insufficient awareness among healthcare providers regarding the distinctive needs of veterans. Mental health issues prevalent among veterans, including post-traumatic stress disorder (PTSD) and depression, contribute to the complexity by impeding proactive engagement in self-care and exacerbating chronic wounds. Additionally, a lack of comprehensive training amongst healthcare providers in veteran-specific wound care further hinders effective treatment. These multifaceted barriers underscore the need for targeted interventions that address geographic disparities, streamline healthcare transitions, enhance mental health support, and provide specialized training for healthcare professionals. This review underscores the importance of furthering interventions to enhance accessibility, improve healthcare coordination, and increase awareness among healthcare professionals. Addressing these barriers is essential to ensure that veterans receive timely and effective wound care, promoting overall well-being, health, and quality of life.
P79.
Purpose:
A tragic complication of diabetes is limb threatening soft tissue and bone infections of the lower extremities. Initial antibiotic choice steers the extent of limb preservation, avoidance of hospitalizations, and other sequelae. We present a patient successfully treated with an oral broad-spectrum tetracycline for a complicated diabetic foot infection, on an out-patient basis.
Methods:
The treatment course of a patient with a severe foot and limb-threatening soft tissue and bone infection secondary to a diabetic foot ulceration was captured. Based on the clinical presentation of the diabetic foot infection, an oral broad-spectrum tetracycline was selected. The local signs and symptoms of a severe, complicated soft tissue infection were routinely assessed during the course of oral treatment with omadacycline. We surveilled edema, erythema, tissue and bone viability, deterioration of the wound, potential abscess formation and reported pain levels. The patient was evaluated until the successful resolution of her lower extremity infection.
Results:
The patient underwent a ten-day course of oral therapy that was undertaken on an outpatient basis. She was strongly cautioned to rest and elevate the affected limb. She began with a loading dose of 450mg, then transitioned to a daily dose of 150mg orally for a total of ten days. The patient reported compliance with prescribed regimen. The infection site was scrutinized for signs of worsening, specifically for abscess formation or deterioration of wound margins. She did not need significant surgical intervention, in particular no resection of infected bone or amputations were performed. The patient’s site of infection demonstrated a consistent reduction in edema, erythema, and pain. Critically, the patient did not require hospitalization, major amputation or a PICC line.
Conclusion:
Antibiotic empiric therapy for complicated, acute bacterial skin and skin structure infections is frequently too broad. Practitioners responsible for the antibiotic stewardship must become more mindful of the novel, safer antibiotic options that exist. There are newer, effective agents that reduce antibiotic-related complications that are better tolerated by patients. Via the selection of a targeted antibiotic, our patient avoided the common sequelae of a potent multi-drug antibiotic cocktail, whilst convalescing at home, and without the life alterating side effects.
P80.
Biofilms are implicated in delayed healing. The 2017 Global Consensus Panel publication established “step down, step up therapy” and “the need for strong initial combination treatment to rapidly and effectively reduce biofilm levels within wounds.”
Wolcott et al. published a 2008 paper discussing a potential critical component to biofilm management thru the mitigation of microvascular hyperpermeability associated with wounds and the deprivation of biofilm nutrients.
The pro-inflammatory state occurs in 3D within soft tissues, including the posterior aspect of the wound, with associated microvascular and endothelial dysfunction and “glycocalyx shedding” (loss into the surrounding tissues of complex sugar components such as glycoproteins, proteoglycans, albumin, hyaluronic acid, etc). Shedding results in endothelial cell dysfunction (loss of mechanotransduction), diffuse microvascular hyperpermeability, resulting in loss of nitric oxide production, decreased inflammatory marker quenching, increased endothelial gap junctions. Dermal lymphatic stasis in peri-wound margins contributes to enhanced periwound inflammation. Endothelial glycocalyx and microvascular hyperpermeability potentially contribute to highly nutritious exudate from surrounding capillaries, enhancing biofilm sustainability.
Dysfunction of endothelial cells and shedding of the endothelial glycocalyx is well recognized to contribute to pathological conditions including diabetes, venous ulcers, atherosclerosis, sepsis, trauma. Could strategies to enhance glycocalyx preservation and/or restoration that improve endothelial cell function with decreased microvascular hyperpermeability enhance biofilm management by removing potential nutritional source to wound beds? The lowering of inflammatory markers, cytokines and associated edema reduction has been demonstrated to enhance healing of venous ulcerations with a variety of venotonics, including micronized purified flavonoid fraction, rutosides and sulodexide. L-Arginine has been noted to reduce edema in a rabbit reperfusion model.
The opportunity to improve outcomes may require a strategy that emphasizes an external biofilm and an “internal” approach that decreases microvascular hyperpermeability and edema, manages the associated inflammation, improves endothelial function, improves microvascular arterial perfusion, oxygen delivery, and dermal lymphatic function, while decreasing the “nutrient” source to the posterior aspect of wounds; an “outside/inside” approach to biofilm management that compliments the consensus guideline “step-down/step-up” biofilm therapeutic strategy. This remains a hypothesis, further benchtop to animal to clinical evaluation is necessary.
P81.
Patients who are homeless regularly must overcome tremendous barriers to obtain health care post discharge from hospitalizations, surgeries, emergency departments, and urgent care clinics. Lack of health insurance and financial hardship are commonly experienced by many people in the United States living below the poverty line. Often, basic needs such as food and shelter outweigh obtaining proper healthcare. An aspect of healthcare that frequently burdens individuals who are homeless is proper wound care. With many homeless individuals experiencing multiple health comorbidities leading to chronic wounds (diabetic ulcers, chronic ulcers, venous insufficiency, lack of properly fitting shoes, needle injuries, injuries from the environment, mental illness, post-surgical incisions), it appears imperative that we must do a better job at implementing effective wound care strategies when working with this specific population. This review prompts a current analysis of what the standard for wound care is in our homeless population in addition to what means this population has to obtain proper materials and education for wound healing. We propose a call to action for emergency departments, free clinics, and shelters to offer additional education and supplies for chronic wounds seen in patients experiencing homelessness.
P82.
Recent advancements in Mohs micrographic surgery (MOHS) procedures have demonstrated a significant reduction in the risk of postoperative infections through the implementation of novel practices. Notably, studies indicate that the use of incisional antibiotics has proven effective in decreasing the rate of surgical site infections associated with skin cancer surgery. Recent findings suggest that intraincisional antibiotic prophylaxis may offer a more efficient and localized method of infection prevention in MOHS procedures. While these emerging practices exhibit promise in reducing infection risks, further research is warranted to delve into the optimal strategies and specific agents for intraincisional antibiotic prophylaxis. Additional studies should explore the ideal timing, dosage, and duration of intraincisional antibiotic administration to maximize efficacy while minimizing potential adverse effects. Comparative analyses between intraincisional and systemic antibiotic prophylaxis could provide valuable insights into the most effective approach for different patient populations and surgical scenarios. Moreover, investigating the potential development of antibiotic resistance and the long-term implications of intraincisional prophylaxis is crucial to ensuring the sustainability and safety of these practices. This poster addresses the most recent findings regarding intraincisional antibiotic prophylaxis and explains the need for why further research is essential to address questions related to dosage, timing, and potential resistance development. Such investigations will contribute to refining guidelines for infection prevention in skin cancer surgery, ultimately enhancing patient outcomes and the overall success of MOHS procedures.
P83.
The Mediterranean diet has proven itself effective in acute and chronic wound healing. A Mediterranean diet includes whole grains, vegetables, fruits, fish, extra virgin olive oil, red wine, and legumes. Foods studied within this diet contain high levels of antioxidants and anti-inflammatory compounds. The diversity of foods and numerous nutritional benefits maximizes wound healing with a variety of protective substances. The Mediterranean diet has high concentrations of polyphenols, carotenoids, vitamins, and flavonoids. Additionally, foods found within the Mediterranean diet are high in protein, zinc, vitamin A, and vitamin C that specifically aid in wound healing and the body’s defenses against infection. A low sodium Mediterranean diet has also been found to strengthen the activation of macrophages to increase the tissue inflammation process and promote wound healing. The consumption of extra virgin olive oil has been found to specifically lower the incidence of dermatological diseases. Specifically, extra virgin olive oil also plays an important role in increased platelet function thus having a direct effect on wound healing and decreased inflammation. Our review addresses how a Mediterranean diet aids with acute and chronic wound healing. The impact of nutrition on wound healing from a Mediterranean diet allows for development of a nutritional approach to minimize incidence of acute or chronic, non-healing wounds via dietary changes.
P84.
P85.
Background: Cellulose nanofibers (CNF) are a fibrous form of elongated nanocellulose that has been the focus of widespread interest for wound healing and tissue engineering. CNF is non-immunogenic and biocompatible due in part to its propensity for low protein absorption. Thus, CNF with its high specific surface area and aqueous gelation properties is a biologically compliant scaffold for potential wound healing applications. We hypothesized that CNF/human- derived hydrogels could maintain structural, healing, and antibacterial properties to promote healing in minor to severely damaged skin e.g. primary wound healing treatment in burn injuries and chronic wounds. The purpose of the study was to develop proof of principle evidence demonstrating the feasibility of cotton and wood-derived CNF scaffolds/human-derived hydrogel combinations (NHC) for cutaneous wound healing applications.
Methods: The study involved the biophysical characterization, biocompatibility, and wound healing capacity of four mass ratio combinations for each of three forms of CNF. For characterization, rheology studies, evaluation of gelation time, protein release studies, proteomics, and microstructure analysis were performed with SEM . The biocompatibility of the nanocellulose/hydrogel combinations was assessed with the proliferative and adipogenic differentiation capacity of human adipose-derived stromal/stem cells (ASCs) and/or human dermal fibroblast cells (DFCs). Finally, wound healing studies were performed using ASCs and DFCs.
Results: CNFs provide support to human-derived material hydrogels. Rheology results demonstrated that nanocellulose responds similarly in combination with human-derived hydrogels. The nanomaterials increase viscosity and hydrogel stiffness in combination with human derived hydrogels. Biocompatibility, promotion of dermal fibroblasts proliferation and ASCs differentiation were assessed. ASCs cultured on a mixture of nanocellulose/hydrogel combinations exhibited increased metabolic activity from days 1-7 and intracellular lipid deposition after adipogenic differentiation. Notably, up to twenty five percent by mass of nanocellulose in the NHCs provides hydrogel support and porosity for cell proliferation. A comparison of three forms of CNF revealed a difference in in vitro wound healing profiles with one form of CNF providing notably enhanced proliferative profiles in the presence of NHC over controls. Proteomics revealed the presence of plant-derived protein, suggesting oversight guidance and activity profiles for CNF preparation.
Conclusions: Hydrogel/cotton and wound-based nanocellulose combination scaffolds display a unique biophysical and biochemical profile that supports human ASC and DFC proliferation, differentiation, and wound healing capacity.
P86.
Background: About 8.2 million people are suffering from chronic wounds, and the treatment costs of chronic wounds ranged from $28.1 to 96.8 billion in 2014 in US. Since venous leg ulcers(VLUs) tend to be chronic due to their high susceptibility to infection and high recurrence rate, they account for the majority of chronic wounds. Patients with venous leg ulcers suffer from diverse symptoms, including pain, fatigue, depression, swelling and exudate, and most patients with VLUs who have delayed healing experience significant symptoms. Biofilm is recognized as an important component of wound non-healing and it is believed that the formation of biofilm delays wound healing. Therefore, by examining wound-related symptoms corresponding to biofilm and inflammatory markers, such as CRP, during the course of wound treatments, clinicians may predict wound healing trajectories. The purpose of this observational prospective study was to 1) characterize the wound-related symptoms (fatigue, pain, exudate, itching, and edema or swelling) and wound related factors (wound area, the presence of biofilm, total bacteria, the level of serum CRP), and 2) explore associations between biofilm and levels of systemic inflammation and the severity of wound-related symptoms in individuals with chronic venous leg ulcers (CVLU) over 8 weeks of wound treatment.
Methods: A total of 117 subjects who received weekly sharp debridement at a wound clinic were enrolled. We collected clinical data every two weeks during the 8 weeks of the study period. Associations among variables were estimated using a Bayesian approach applied to general linear mixed models.
Results: Based on Bayes Factor (BF) value, there was moderate evidence of a direct association between biofilm presence and levels of C-reactive protein (CRP) (BF 4.3) and moderate evidence of direct associations between biofilm and wound-related symptoms; pain and exudate (BF 5.12, 8.49 respectively). There was extremely strong evidence for the association of biofilm with mean total bacteria.
Conclusion: This study is the first to examine associations among biofilm, inflammatory response, wound-related symptoms, and wound healing in clinical settings. Wound-related symptoms and the level of systemic CRP were associated with biofilm among patients who were receiving weekly sharp debridement. Symptom severity associated with CVLU requires clinical assessment and management. Symptom severity and level of systemic CRP may be biobehavioral markers for predicting wound healing trajectories.
P87.
P88.
Pressure ulcers are a major issue in contemporary healthcare, with prevalence and incidence rates of 12.8 and 5.4% respectively based on the 2008-2018 data from a systematic review in 2020.The implementation of pressure ulcers(PUs) prevention is essential for all patients however only two-thirds of Korean nurses are reported to be performing PU prevention tasks, such as risk assessment. Nurse with greater knowledge of PU prevention would be expected to perform it more often than those with less knowledge. The purpose of this study was to evaluate the psychometric properties, including content validity, validity of multiple choice items, and the reliability of the Korean version of the Pressure Ulcer Knowledge Assessment Tool (K-PUKAT 2.0), using classical test theory (CTT) and item response theory (IRT). Linguistic validation process and factor analysis were conducted among wound care nurses, staff nurses and nursing students. Items were analysed according to the CTT and IRT using a two-parameter logistic model. Intraclass correlation coefficients were used to examine reliability. A total of 378 wound care nurses, staff nurses and nursing students participated in this study. While most items showed moderate difficulty based on the CTT, difficulty index values based on the IRT were more broadly distributed (low: 5 items; moderate: 9 items; high: 1 item). The intraclass correlation coefficient for K-PUKAT 2.0 was 0.72. The K-PUKAT 2.0 demonstrated concise and good psychometric properties. Based on the results of this study, repetitive use of K-PUKAT 2.0 will not only help in distinguishing whether an individual has sufficient clinical knowledge, but will also play a key role in supporting learning.
P89.
Expression of pro-inflammatory cytokines by human dermal fibroblasts occurs when the cells are activated by cellular injury. We have reported previously, using an in vitro wound model, that within 8-12 hours of wounding a fibroblast monolayer, cells express and secrete a number of cytokines including interleukin (IL) -1, 6 and 8. We had hypothesized that this expression arose from cells immediately adjacent to the area of wounding, however we now report that cells at several cell distances from the wound grid express these cytokines suggesting that a compound released from injured cells may trigger this cell expression.
Non-transformed human dermal fibroblasts (GM23973 and GM1872, Coriell Institute) were obtained from the NIGMS cell bank and cultured under standard conditions. The cells were seeded onto acid-stripped glass coverslips grown in 6-well plates using DMEM medium containing 10% FBS and penicillin/streptomycin. Upon confluence, the coverslips had cells scraped in a grid pattern and IL-8 localized by immunofluorescence using FITC-labelled primary antibody (BD Bioscience) at various times post scraping. Total immunoreactive IL-8 secretion from confluent cell monolayers following scraping was also performed in large cell culture dishes by ELISA (Raybiotech) and Western blotting.
Findings of note were that cells immediately adjacent to the scraped area showed variable expression of IL-8 with many cells not showing any expression. In contrast, cells away from the scraped edge showed the brightest immunofluorescence. This suggested that cells at the immediate edge, which are either migrating or entering for cell division, may not also express pro-inflammatory genes. These cells may release soluble mediators to stimulate other cells in the wound area to express inflammatory mediators, or factors released from the scraped cells are able to act as paracrine mediators.
Based on cell injury in epithelial cells, we also examined the potential that uridine 5’-diphosphate (UDP) released from damaged fibroblasts could serve as a soluble mediator to activate the distant cells. Preliminary studies with LC/MSMS failed to detect significant levels of this nucleotide in culture media after scraping. Addition of exogenous UDP also failed to significantly enhance fibroblast monolayer expression of these ILs. Suggesting that in fibroblasts this compound is not involved with the injury response.
These findings suggest that fibroblast IL expression is dynamically regulated with cells triggered to move and/or proliferate showing less IL synthesis whereas cells that are not directly impacted by injury show significant expression. Understanding the biochemical triggers for this induced production of ILs may lead to pharmacologic approaches to reduce excess inflammation in problematic wounds.
P90.
P91.
Backgrounds
Polydatin (PD, 3, 4’, 5-Trihydroxystibene-3-beta-monoglucoside) is a monocrystalline drug isolated from Polygonum Cuspidatum. It has obtain permission for phase II clinical trials from the Chinese Food and Drug Administration (Clinical Trials.gov identifier: 2006L00301), as well as from the American Food and Drug Administration (Clinical Trials.gov identifier: NCT 01780129). This study tests the hypothesis that polydatin attenuate vascular hyperpermeability after burn by inhibiting the activation of the intrinsic apoptotic pathway.
Materials and Methods
Scalp-induced edema model of rat ears was used to find out the effect of polydatin gel. Experimental rats which subjected to burn injury covering 30% of the total body surface area were used to explore its mechanism. PD, cyclosporine A (CsA), or resveratrol (Res) was administered to the animal model after burn injury. The rats were injected with fluorescein isothiocyanate albumin (50 mg/kg), and changes in the integrated optical intensity of the postcapillary venules were determined by intravital microscopy. The permeability of mesenteric venules was assessed. Expression of cytochrome C and Smac in cytosolic fraction, as well as expression of Bcl-2 and Bax in mitochondrial fraction, were analyzed by Western Blotting. Caspase-3 activity was detected with Caspase-3/CPP32 Fluorometric Assay Kit.
Results
The permeability coefficient of the burn skin venules in the burn+NS group was higher than that in the sham burn group (P< 0.01). Observed by the video micro scaler, pinnae swelling was obvious in rats immediately after burn, and no blood circulation could be detected. The wound edema reduced and the blood flow began recovery after 6 hours after PD administrating. Treated with CsA, Res, or PD resulted in a reduction in the FITC-BSA extravasation. The results of Western Blotting indicated that the levels of cytochrome c and Smac in the cytosol of the mesenteric vasculature in the sham burn group were significantly lower than those in the burn+NS group at 6 h after burn. Treatment with CsA, Res, or PD reduced the cytosolic release of cytochrome c and Smac. This reduction was more significant in the burn+Res and burn+PD groups (both, P< 0.01) than in the burn+NS group. Burn injury resulted in the upregulation of Bax proteins and downregulation of Bcl-2 in the rat mesenteric microvasculature. Treatment with CsA, Res, or PD could attenuate these changes to some extent. The level of caspase-3 activity in the mesenteric microvasculature showed that the level was increase in the burn+NS group, the burn+Res and burn+PD groups showed significantly lower levels (both P< 0.01) than the burn+NS group after treatment.
Conclusion
PD markedly attenuated burn-induced local and systemic hyperpermeability which caused by the activation of endogenous apoptotic signaling pathway.
P92.
P93.
While scar healing by fibrosis is a wound healing strategy that we mammals are equipped with, it is also the cause of many intractable diseases such as keloids and pulmonary fibrosis. Although numerous studies have been conducted to inhibit fibrosis, the inflammatory response that leads to fibrosis is also required for beneficial repair processes, so targeting it for disease treatment is still expected to be challenging. To identify fibrosis-suppressed regenerative therapeutic strategies, we focused on the special regenerative potential of newts, which belong to the salamander family of tailed amphibians. Many studies have shown that newts maintain a strong regenerative capacity throughout life without fibrosis even after reaching adulthood beyond metamorphosis. Considering that even amphibians with strong regenerative abilities lose or decline their regenerative abilities as they grow, it is likely that newts have an unknown regenerative factor. In this study, we report our findings that newt plasma may confer fibrosis-inhibitory properties on mouse fibroblasts across species. First, to determine the effect of newt plasma on mouse fibroblasts, we examined cell viability after the addition of newt plasma. To avoid variation due to individual differences, whole blood was collected from each of five blastema. After isolating plasma from the whole blood samples, cell viability at 72 hours was evaluated. The results showed that the administration of newt plasma within the range of 0.1% to 1% had no lethal effect on mouse fibroblasts. Next, we tested the inhibitory effect of the addition of newt plasma on fibrosis by using TGF?1 to induce fibroblast differentiation into myofibroblasts in an assay. Fluorescent immunostaining using F-actin and ?SMA as markers showed that the expression of both was attenuated by the addition of newt plasma. Quantitative evaluation using Western blotting confirmed that the addition of newt plasma reduced the amount of ?SMA to the same level as the control group. This suggests that the addition of newt plasma may have inhibited the induction of differentiation into myofibroblasts. To further identify the location of fibrosis inhibitory factors, we focused on extracellular vesicles (EVs) and isolated EVs from newt plasma by ultracentrifugation. We performed the same experiment with the isolated EVs as with plasma addition, and found that the same effect was obtained. This suggests that newt plasma has the ability to suppress fibrosis across animal species, and that it is highly likely that plasma EVs contain factors that can suppress fibrosis. This research may offer new possibilities for regenerative medicine.
P94.
Background
In medicine, the treatment of diabetic wounds is one of the most difficult to get good results. Despite thousands of wound dressings developed in the past century, none has shown any good effect to enhance the healing process, including the only FDA-approved prescription growth factor, Regranex.
Multiple factors contribute to nonhealing diabetic wounds, and many of the pathways involved are not entirely clear. Surgeons have long recognized that ischemic tissues heal poorly and are easily infected. One direct effect of ischemia is a reduction of tissue high energy phosphate reserve.
Methods
We have developed an intracellular ATP delivery (ATP-vesicles) to enhance wound healing by providing direct high energy phosphate. When used in animal experiments, it has shown extremely rapid tissue regeneration—granulation tissue starts to appear very quickly after surgery. We hypothesized that tissue ischemia was one major contributing factor in diabetic wound healing, and if exogenic energy is provided, healing should be enhanced.
Twenty-five diabetic rabbits were used in this study. Diabetes was induced by alloxan (100 mg/kg) IV injection. After stable diabetes was established, the rabbits were kept for 3-12 months before wound study. In each rabbit, the left ear was made ischemic using vascular disruption or adding a silicone ring buried in the ear base to limit vessel and nerve regeneration. The right ear vessel and nerve supply was not disturbed as normal control. Four wounds (5 mm in diameter) were created on the ventral side of each ear, resulting in 100 ischemic wounds and 100 non-ischemic wounds. On each ear, the two wounds on one side were treated with ATP-vesicles while the other two wounds were treated with Regranex (50 for ATP-vesicles and 50 for Regranex).
Results
Many of the wounds treated by ATP-vesicles started to have new growth only 1 to 2 days after surgery while the wounds treated by Regranex did not have new growth before day 5. The wounds treated by ATP-vesicles were healed much faster than the wounds treated by Regranex. Histologic study shows that the use of ATP-vesicles increased tissue collagen production quickly and this was accompanied by very early and massive platelet trafficking followed by massive macrophage accumulation and rapid direct collagen production, resulting in much faster wound healing.
Conclusion
Our results show that using intracellular ATP delivery can enhance wound healing in long-term diabetes, and this is accompanied by rapid macrophage accumulation, in situ proliferation, and direct collagen production.
P95.
P96.
Ultra-fine bubbles, measuring less than 1 ľm in diameter, are stable and effective for cleansing various materials. Recently, a chemical method using sophorose lipids has been developed to generate ultra-fine bubbles, known as Soforo-fine bubbles (SFB). Previous reports have highlighted the efficient removal of in vitro biofilms by SFB. This study aims to demonstrate the practical utility of SFB in cleansing critically colonized wounds through two animal experiments. Two full-thickness wounds were created on the dorsal skin of a rat and cleansed daily with either SFB or control solutions. In Experiment 1, normal wounds were created to assess the safety of SFB. In Experiment 2, critically colonized wounds were prepared to demonstrate the effect of SFB on wound healing. In both experiments, the healing period and relative wound area were compared between the groups. This study was conducted with the approval of the Animal Experimentation Committee of the University of Tokyo. In Experiment 1, there was no difference in the healing period between groups (p = 0.178). On post-wounding days (PWDs) 9, 10, 12, and 14, the relative wound area was significantly smaller in the SFB group compared with the control group. In Experiment 2, the SFB group had a significantly shorter healing period (14.3 ą 0.50 days vs. 15.5 ą 0.58 days, p = 0.015) and a smaller wound area on PWDs 5, 6, 9, and 13 compared with the control group. These results indicate that cleansing with SFB has no negative effect on normal wound healing and, importantly, promotes healing in critically colonized wounds.
P97.
Background
The leading cause of death on the battlefield, in surgical wards, and in other severe trauma situations is active bleeding. Current hemostatic devices form a powdery substance of non-degradable minimal-absorbable efficacy granules, which in turn irritate and delay wound healing, additionally, the exothermic effect of the granules can cause second-degree burns and at times it may lead to necrosis of the surrounding tissues.
With all these in mind, our researchers developed a powdery composition (substance). In our composition, the natural semisynthetic polymers break down into micro molecular elements, similar to glucose, and are eliminated from the body without a trace, without side effects or reaction to the host body.
Methods & Results
Resorption rate: In vitro studies Celox and our K1 as a study material weighing 1 g each placed in a measuring tube containing 5 ml of distilled water. Then it was placed in a thermostat with a constant temperature of 37 °. The rate of biological degradation of hemostatic material was evaluated on days 1, 3, 7, and 14.
The studied hemostatic material was dried. The difference in the mass of the hemostatic material before the experimental study and after its implementation was measured in percent and reflected the rate of resorption of the studied agent (HM). The maximum resorptive activity was observed with the K1 composition.
Sorption activity: In vitro studies Celox and our K1 as a study material weighing 1 g each put into distilled water. The degree of full saturation of the studied hemostatic material (HM) was determined visually, based on the changes in swelling. To assess the sorption activity of the studied materials, their hygroscopicity was determined.
For a comprehensive assessment of the sorption properties of hemostatic materials, we used a sorption index (SI). The sorption rate of K1 was far superior to Celox.
Bleeding time based on compression effect: The experiment was carried out on 80 male Wistar rats. A median laparotomy was performed under anesthesia and modeled a standard injury of the liver and spleen. A hemostatic agent was applied in the wound area in the amount fitting to the size of the injury. Bleeding time was measured with a stopwatch.
The bleeding time from liver injury after applying K1 was decreased by 89.5-93.5% relative to the control group with similar injuries. The shortening time needed to stop bleeding from the experimental spleen injury was mainly observed with the K1 compound (p <0.001).
Conclusions
Our new generation of hemostatic substances with a binary effect can be used on the battlefield, in hospitals, and by surgeons in life-threatening uncontrolled bleeding situations. It absorbs 70 times the amount of blood compared to existing hemostatic products and is easy to manufacture.
P98.
Background
Pluripotent stem cells are known for their role in rejuvenation and supporting a robust immune system. Pluripotent stem cells become scarce as the body ages. To overcome these challenges, our researchers identified two groups of compounds cAMPphosphodiesterase and histone deacetylase inhibitors which, when combined, significantly increased the yield of stem cells after genetic modification. Despite the need for genetic modification, the yield of stem cells increased substantially a thousand-fold.
Methods
To assess the wound-healing properties of different compounds, experiments were conducted on male Wistar white rats with skin wound. A total of 38 animals were previously anesthetized, and a skin area measuring 2 by 2 cm was cut out on the dorsal side of the body, behind the right shield bone. Using forceps, the skin was pulled back, resulting in a skin fragment of 2 cm in size and a cut depth of 2 mm, leading to an average wound area of 3-5 cm2. The wound, characterized by polygonal shape, exhibited intense bleeding.
Subsequently, two substances, Dipasol FC and Dipasol aerosol substances, were applied to the wound of groups 1 and 2 (each consisting of 10 rats). Group 3, also comprising 10 rats, was treated with “panthenol,” while the wound of the control group (group 4, consisting of 8 animals) were left untreated. The application of these substances involved ensuring that the formed aerosols covered the entire wound surface and a small skin area around it. BF-6 glue was subsequently applied on top of the aerosol and left to dry. Following this, the animals were reintroduced to their cages. A parallel study was also conducted on guinea pigs.
Results
A planimetric study was conducted on days 3, 6, 9, 11, and 13 after the start of the experiment to evaluate reparative processes before complete wound healing. The assessment involved applying celluloid film to the wound, plotting wound contours on the film, and determining the wound surface area using graph paper. This methodology provided insights into the features of the wound healing process over time, allowing for a comprehensive analysis of the effectiveness of the tested substances in promoting skin regeneration.
Conclusions
In a rat model with stencil wound, the topical aerosol application of Dipasol accelerated skin regeneration by 2 times. A guinea pig study Dipasol aerosol application accelerated wound healing by 5 times. These findings suggest a potential breakthrough in regenerative medicine, paving the way for improved wound healing and possibly addressing the challenges associated with aging through pluripotent stem cell enhancement.
P99.
Background: Diabetic wounds represent significant challenges in healthcare, impacting over six million individuals in the United States. Compromised healing, resulting from diabetic condition, is exacerbated by the formation of biofilms. The progression of infection results in inflammation and reactive oxygen species (ROS), contributing to vascular damage and attenuated healing rates at the wound site. Conventional commercial bandages and wound dressings fall short in addressing these complexities. To address this issue, we have developed silk-based composite bandages tailored for wound healing. In this study, metal substituted cerium oxide nanoparticles (M-CNPs), and microRNA-146a (miR146), when incorporated into silk composites, can serve as antimicrobial, anti-inflammatory, and antioxidant components in a wound covering product.
Methods: The M-CNPs synthesized by a wet chemical method. The miR146 encapsulated alginate (SA)-chitosan(C)-collage (Col) beads were fabricated using encapsulation equipment. M-CNPs/silk composite films were initially fabricated by a solution casting method and then miR146 beads infused into M-CNPs/silk film to produce a novel composite bandage for wound healing. Fabricated materials were then characterized via FTIR, UV-Vis, X-ray photoelectron spectroscopy (XPS), SEM and TEM; in particular, to confirm nanoparticle and miRNA incorporation. The composite film was cultured with HUVEC cell for 1 and 3 days and then analyzed for cell death/proliferation using WST-1 assay. In addition, a commercial angiogenesis assay kit was used to analyze angiogenesis induction by fabricated films in HUVEC cultures.
Results: XPS determined that Ce4+/Ce3+ ratio and amount silver incorporation are essential in observed antioxidant and antimicrobial properties by incorporated nanoparticles. M-CNPs maintained their ROS scavenging abilities following composite incorporation. In vitro study, release of miRNA and M-CNPs and antioxidant were determined using UV-Vis technique and commercial kit. The cell studies showed no significant cytotoxicity for fabricated bandage treated cells. Further, we observed an increase in angiogenic network formation for fabricated bandage film. Based on this result, we propose that the tested fabricated bandage film can be effective in reducing the ROS, microbial infection, inflammation, and increasing angiogenesis; thus, accelerating the healing rate of wounds.
Conclusion: The results demonstrate that fabricated bandage film can provide combinational therapy deliverable to wound sites. The results showed substantial efficacy in scavenging ROS, limiting microbial infection, inflammation, and enhancing angiogenesis. To the authors’ knowledge, the studies material is the first description of a wound healing bandage to incorporate miRNA technology.
P100.
Keloid treatment is challenging. From May 2021, we have treated 683 keloids with surgery combined with hypofractionated radiotherapy. We have used several strategies in our case series. Complete excision followed by primary closure in single or multiple stages, complete excision plus local flap coverage in a single stage, intralesional excision with biopsy punch device with/without closure, triple combination therapy, debulking surgery, postoperative single dose radiotherapy or two fractions, and closed incisional negative pressure wound therapy is one of those. Through this presentation, we would like to give you valuable insights into the beautiful orchestration of this combined surgery plus hypofractionated radiotherapy approach.
P101.
Background: Chronic wounds are those present for more than 4 weeks failing to produce anatomical and functional skin integrity being predominantly a condition of old individuals are with chronic illness. We also face challenges in aesthetic surgery. Methods and Results: 4 chronic complex wound showing the association of new technologies to accelerate the healing process. Case 1: 65 years old (yo) woman ,30 days after an abdominoplasty and liposuction with the use of Renuvion®, septic, anemic and with 25% of a third-degree burn surface area. We started slowly because of the bad patient’s conditions, using the Cleanse Choice therapyTM for 3 times, every 48 hours. After that we finished to debride all the areas and started closing with local flaps or use dermal matrix (Nevelia®) and V.A.C.® therapy. After the skin grafts, there were a few graft losses. We used extracellular matrix from sheep fore-stomach (Endoform®), alginate plus silver (Silvercel®) and Mepilex Border®. After 5 weeks we discharged the patient, feeling well and with her self-esteem back. Case 2: 43 yo man, type II diabetes, dialytic with recurrence of a lesion at his right foot already partially amputated. At the first procedure we reduced the ulcer at a minimum size, after full debridement and local flaps we filled all empty spaces with Endoform® and used V.A.C. After one week, full granulation, were able to graft. After 3 weeks total, the graft became full integrated and the patient was back to his job. Case 3: 65 yo old woman with a donor site infected with a multiresistant germ. After the debridement we used Endoform® with antimicrobial, Silvercel® and Mepilex Border®. The patient also received systemic antibiotics. After 3 weeks the wound was totally closed. Case 4: a paraplegic 66 yo man with an ischiatic pressure sore, treated several times before by other teams, inclusive ours, 3 years ago, successfully. This year he appeared with a lesion similar to an excoriation. We found a huge seroma inside a fibrotic capsule and we made all the investigation to rule out osteomyelitis. After closing the wound with local muscle flaps, there was still slough at the edge of the skin. We covered it with Endoform® and Prevena Plus®. We obtained good results both at the incision and around it. After 3 weeks the patient got back to work. Conclusion: after a correct diagnosis made by multidisciplinary team, we sometimes must gather novel technologies to give our patient as much comfort as possible, discharge faster and be able to make the follow up on an ambulatory basis, with the best cost benefit results, not only considering the money spent but also the quality of life to our patients.
P102.
Purpose: Review the current evidence on the effectiveness of acupuncture for wound healing and its biological basis. Background: Organizers are small groups of cells which control growth and differentiation of a larger region. Their structure and function have been well established in embryogenesis. Organizers are singular points of morphogen gradient field and bioelectric field. They can be activated by nonspecific subtle stimuli such as needle prick causing long lasting growth control effects. The organizer model of postembryonic growth control suggests that a network of organizers continues to exist after embryogenesis and plays a critical role in regulating tissue growth and repair. Acupuncture points (acupoints) likely originate from the organizers. Acupuncture has been shown to have extensive growth control effects and can promote wound healing. Organizers and acupoints have been confirmed to share many similarities as predicted. Methods: A literature search was conducted in Pubmed and Google Scholar to identify relevant studies using keywords (acupuncture OR acupoint) AND (wound healing). Studies were included if they met the at least one of the following criteria: (1) they were randomized controlled trials (RCTs); (2) they investigated the effect of acupuncture on wound healing; (3) they reported outcomes related to wound healing, such as wound size, healing time. Results: Several studies including RCTs on both human and dogs met the inclusion criteria. The results of the studies showed that acupuncture was more effective than sham acupuncture in promoting wound healing in a variety of wound types. The effect sizes were small to moderate, but statistically significant. Acupuncture can promote wound healing by increasing the release of interleukins, the expression of growth factors such as vascular endothelial growth factor and transforming growth factor-?1, and regulating phosphatidylinositol-3-kinase/protein kinase B as well as mitogen-activated protein kinase. Conclusions: Acupuncture can be effective for wound healing by activating the organizers of growth control and increasing the wound healing response. Further research is needed to fully understand the mechanisms by which acupuncture promotes wound healing and to determine the optimal therapeutic parameters for wound healing. The development of wearable medical devices with low intensity transcutaneous acupoint stimulation can improve the cost effectiveness of wound healing.
