Micro-architectural Analysis Of Unscarred And Scarred Human Dermis Provides Structural Insight For Future Scaffold Design
Umair Khan, Ardeshir Bayat.
University of Manchester, Manchester, United Kingdom.
INTRODUCTION The three-dimensional (3-D) spatial arrangement of dermal tissue plays a crucial role in directing cellular behaviour during wound healing. Thus, it is crucial to elucidate a better understanding of the three-dimensional dermal architecture of the human skin. The aim of this project was to understand the configuration in morphological structure of decellularised human dermis between unscarred skin and normal cutaneous scars. METHODS Skin samples were obtained from ethically consented volunteer patients undergoing Abdominoplasty surgery. All skin samples underwent decellularisation as previously described (DNA removal = 88%.). Histological sections of cellular and decellularised dermis were subsequently analysed using standard haematoxylin and eosin (H&E), and 4’,6-diamidino-2-phenylindole (DAPI) stains. In addition, extent of decellularisation was quantified using an Easy-DNATM isolation kit. Nanomechanical and structural evaluations were performed using Atomic Force Microscopy (AFM) and Multiphoton Microscopy (MPM). RESULTS Interestingly, there was no change in the gross morphology of decellularised unscarred and scarred dermis, under light microscopy. However, MPM and AFM showed that collagen fibers in unscarred decellularised dermis were arranged randomly. Collagen fibers of decellularised unscarred dermis appeared to have a significantly rougher (Rq-16.5, Ra-12.5, Rmax-198; p<0.0001) surface topography. Based on AFM reduced modulus values, collagen fibers of unscarred decellularised dermis were less stiff (mean 2.155 MPa ± 0.9595; p<0.0001) compared to decellularised scarred dermis. MPM demonstrated that collagen fibers in unscarred dermis are interwoven, akin to a mesh-like structure. Further, scarred dermis has a higher collagen volume density. CONCLUSIONS Decellularisation of unscarred and scarred dermis was successfully achieved. The parameters addressed in this study should be carefully considered when developing engineered scaffolds for dermal wound repair. Ideally, the scaffolds should exhibit a mesh-like structure with a rough surface and low stiffness, which represents the microenvironment of unscarred dermal tissue.
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