Comparison between cryopreserved and glycerol-preserved allografts in a partial-thickness porcine wound model

Abstract

Human skin allografts are one of the best temporary biological coverings for severely burned patients. Cryopreserved (CPA) and glycerol-preserved (GPA) allografts are the most widely used types. This study compared the allograft efficiency of both preservation methods under the same conditions. To simulate actual clinical conditions, we used a porcine wound model. In addition, we evaluated the macroscopic and microscopic scoring of graft performance for each method. Porcine cadaver skin 1 mm thick was obtained from one pig. Cryopreserved skin cell viability was 20.8 %, glycerol-preserved skin was 9.08 %, and fresh skin was 58.6 %. We made ten partial-thickness wounds each in two pigs. The take rates on day 2 were 96.23 and 82.65 % in the GPA and CPA group (both n = 9), respectively. After 1 week, the take rates of both groups were nearly equal. The removal rate at week 5 was 98.87 and 94.41 % in the GPA and CPA group, respectively. On microscopic findings at week 2, inflammation was greater in the CPA group. Other findings such as fibroblast hyperplasia and neovascularization were not significantly different between both groups. At week 5, the score of collagen fiber synthesis was 2.67 ± 0.47 and 2.33 ± 0.47 in the GPA and CPA group, respectively. The epidermal-dermal junction was 2.22 ± 0.79 and 2.00 ± 0.47 in the GPA and CPA group, respectively. These findings suggest that wound healing takes longer in the CPA group. The preservation method of allografts is not a absolute factor in the wound healing process in this wound model.

High Throughput Screening of Additives Using Factorial Design to Promote Survival of Stored Cultured Epithelial Sheets

“…Although glycerol has been widely used as a cryoprotectant, its use in preserving the essential qualities of cultured cell sheets at above freezing temperatures pretransplantation has not been explored. It has been reported that pig skin allografts can be successfully preserved with 85% glycerol when kept at 4°C [23, 24]. Studies have shown that a lower concentration of glycerol (<6% in cell culture or intratesticular injection of a 10% glycerol solution) suppresses proliferation [25, 26].…”