(WHS-K4.03) LASER MICROPATTERNED DERMAL TEMPLATES IMPROVED CULTURED EPITHELIAL AUTOGRAFT HANDLEABILITY AND DEVELOPMENT IN VIVO
Thursday, May 16, 2024
9:15 AM – 10:15 AM East Coast USA Time
The success of cultured epithelial autografts (CEAs) as a treatment for large surface area burns is limited by graft fragility and resulting issues with handleability and blistering. Rete ridges play a significant role in epidermal adhesion; however, they are commonly missing from cultured skin grafts and CEA-treated wounds for up to one year. The purpose of this study was to explore whether a fibroblast-seeded dermal template (DT), fabricated with a dermal papillae-like architecture, could facilitate faster rete ridge development and improve the outcomes of CEA application in vivo. A porcine burn-excise-autograft model was used to establish a viable, partial thickness wound bed for grafting of CEAs alone or in conjunction with a flat (CEA+Flat) or micropatterned (CEA+Ridged) DT. Porcine keratinocytes and fibroblasts were isolated from split-thickness skin grafts from four subjects. Keratinocytes for each pig were cultured for 20 days to form CEAs. After expansion, fibroblasts from all pigs were pooled and seeded onto disinfected, hydrated electrospun collagen scaffolds to form DTs. A fractional carbon dioxide laser was used to micropattern the surface of half of the DTs prior to combination with the CEAs. For 9 weeks, grafts were assessed for contraction, epidermal barrier function, pigmentation, erythema, biomechanics, basement membrane formation and vascularization. Combinatorial use with a DT improved handleability and graft integration at the margins, and speeded restoration of epidermal barrier function by 2 weeks. At 2 weeks post-grafting, increased epidermal proliferation and localization of collagens IV and VII near the dermal-epidermal junction were observed in CEA+Ridged grafts, over CEA alone and CEA+Flat groups. Additionally, rete ridges were observed in all CEA+Ridged grafts from week 2, while these features were less frequent and shallower in CEA alone and CEA+Flat grafts over the course of the study. No differences between the groups were found in graft contraction or post-grafting biomechanics, and a stiffer substrate may better mitigate graft contraction for future use with epidermal sheets or suspensions. Overall, inclusion of a laser micropatterned dermal template improved graft development and decreased variability overall.