Assessment of the biological properties of human split skin allografts disinfected with peracetic acid and preserved in glycerol

Skin allografts derived from cadaveric human donors are widely used in the treatment of serious burn injuries and other conditions, such as ulcers. In order to render these allografts safe for clinical use, and to enable them to be preserved and banked for long periods, effective methods of decontamination and preservation are required. These methods must not adversely affect graft properties essential for clinical performance. We have investigated the application of a peracetic acid (PAA) disinfection protocol, coupled with preservation in either glycerol or propylene glycol to achieve these goals. An effective decontamination procedure, comprising of a 3 h exposure to 0.1% (v/v) PAA in phosphate buffered saline (PBS) at pH 7.0, was developed and had no significant detrimental effects on the structure of skin. Cadaveric skin allografts were then treated with this disinfection protocol and subsequently preserved in either 85% (v/v) glycerol or propylene glycol in PBS, and the biological properties of the allografts thought to be essential to successful clinical performance were assessed. The cytotoxicity of the grafts was assessed using both extract and contact assays; damage to the skin collagen was assessed using a collagenase susceptibility assay and the capacity of the grafts to elicit an inflammatory response in vitro was assessed by quantifying the production of the pro-inflammatory cytokine TNF-α by human peripheral blood mononuclear phagocytes. Neither the disinfection protocol nor either of the preservation techniques rendered the grafts cytotoxic or pro-inflammatory. The PAA disinfection and glycerol preservation protocol had no effects on collagenase susceptibility, whereas the disinfection protocol in combination with propylene glycol rendered some of the test samples significantly more susceptible to collagenase digestion. Therefore, this study has demonstrated that PAA disinfection combined with glycerol preservation is suitable for skin allografts. The use of propylene glycol as a preservation agent for skin requires further development.