Temporal Viability Assessment of an Autologous Homologous Skin Construct Compared to Healthy Full-Thickness Skin

Abstract Body: Introduction: Multiple studies have demonstrated the efficacy of increased cell and tissue viability on skin allograft and human cell transplantation uptake, as well as reductions in healing times, morbidity, and mortality.1 Additionally, epidermal, dermal, and subdermal cells must retain viability to form functional stable grafts upon transfer to a wound bed.1 A commercially available autologous homologous skin construct (AHSC) derived from the patient’s own skin has been shown to close difficult-to-treat wounds.2-4 The aim of this study was to evaluate the viability of AHSC relative to native skin over time as the healing capabilities of skin have been shown to be proportional to the amount of viable tissue present.   Methods: Full-thickness skin from volunteer human-research abdominoplasty patients was cut into 4- 9cm2 pieces and stored in saline +0.5 mg/mL gentamicin in a 50mL conical tube at 4°C. Equivalent amounts of AHSC were generated and stored at 4_C. The alamarBlue™ assay was used to assess the viability of six native skin and AHSC samples derived from the fresh abdominoplasty tissue. alamarBlue™ readings were taken at 1, 5, 10, and 14 days post-harvest. Eight 6-week-old nulliparous female athymic nude mice (Crl:NU(NCr)-Foxn1nu; strain 490) were used in accordance with an approved IACUC protocol. A single surgery under general inhalant anesthesia was performed to create two 8mm full thickness thoracodorsal excisional skin wounds on each animal. 25mg of AHSC manufactured from human skin samples 1, 4, or 14 days post-processing was applied directly to the left wound to assess graft take of the AHSC. Statistical analyses were performed in GraphPad-Prism v8.0.2.   Results: Native skin and AHSC viability were not significantly different from each other (P=0.20). Both were significantly elevated above dead after initial processing (native p < 0.0001, AHSC P < 0.0001) and AHSC viability was significantly elevated above native after storage at 4_C for a two-week period (P < 0.0001).  Finally, human AHSC samples deployed onto five mice had 100% graft take in an athymic nude mouse model.   Conclusion: Collectively, this data shows that AHSC processing consistently resulted in viable tissue over an extended time period and could contribute to graft take and wound closure.