J. A. Ungar1, L. Fu2, S. Aravind1, J. Xie3, M. Carlson1 1University Of Nebraska College Of Medicine,College Of Medicine,Omaha, NE, USA 2University of Nebraska Medical Center,Regenerative Medicine,Omaha, NE, USA 3University of Nebraska Medical Center,Surgery – Transplant,Omaha, NE, USA
Introduction: For dermal defects in diabetic subjects, both split thickness skin grafting (STSG) and dermal replacement products are minimally effective in preventing wound contraction. We hypothesized that treatment of full-thickness skin wounds in diabetic rats with a composite of autologous skin islands embedded in a nanofiber scaffold (NFS) would produce less wound contraction compared to standard skin grafting.
Methods: NFS were electrospun from PCL and gas-expanded to produce a 2mm thick microporous matrix arrayed with 1mm wells (skin island placement) spaced 3mm apart. Wistar rats (3mo/300g, N=35) with STZ-induced diabetes underwent dermal wounding (2cm circular excision, two per dorsum) with an encircling ring tattooed around each wound. Subjects were randomized to receive immediate application of a wound treatment: (1) gauze only; (2) meshed STSG; (3) NFS only; (4) 1mm skin islands, or SI, every 3mm; (5) NFS+SI. Gross wound area (WA) and tattoo area (TA) at days 0, 14, 28 and microscopic cross-sectional granulation tissue area (GTA) at days 14, 28 were determined with digital planimetry.
Results: WA and TA on day 0 were not different. At d14, WA in the SI group was less compared to the other groups (Table 1). At both d14 & 28, wounds treated with any NFS had greater GTA compared to other groups. At d28, wounds were 90+% closed, based on WA & GTA. The NFS+SI group demonstrated the least wound contraction at d28, having the greatest TA and the smallest change in WA. However, the NFS+SI group also had the greatest GTA at d28. On d28 H&E histology, the skin islands in the NFS+SI groups were viable, but the NFS was only minimally incorporated into the underlying wound.
Conclusion: Dermal excisional wounds in diabetic rats treated with a NFS-autologous skin composite had less wound contraction compared to other treatments, including STSG. However, the mechanism for this effect may involve physical splinting or some other effect, since the NFS-treated rats only had minimal incorporation of the synthetic construct into the wound, while having greater area of granulation tissue. In order to obtain a dermal replacement which both prevents wound contraction and strongly incorporates into the wound, NFS modification likely will be necessary.
