Cryopreserved Skin Transplantation in a Nonhuman Primate Model

Skin transplantation is often used in nonhuman primate (NHP) transplant research for sensitization and to assess tolerance. However, the availability of donor animals for skin can be constrained after organ donation. In this study, we evaluated the feasibility of cryopreserving skin patches to address this issue.

A full-thickness dorsal skin section with a diameter of ∼3 cm was excised. Following defatting process, the skin graft was immersed in a skin-cryopreservation media and preserved in liquid nitrogen. Prior to transplantation, the frozen skin was rapidly thawed using a 37°C water bath and thoroughly washed with normal saline. Cryopreserved syngeneic skin transplantations were performed, monitored, and assessed histologically.

Autologous skin grafts preserved in liquid nitrogen with prolonged storage time (>1 month) demonstrated successful engraftment in NHP recipients. The cryopreserved skin exhibited well-preserved epidermis and dermis, with minimal distinction compared to non-cryopreserved samples. In fully engrafted cryopreserved skin grafts, dermal fibrosis appeared slightly less distinct at 28 days after transplantation. These differences could be attributable to anatomical location of the samples.

The cryopreserved skin showed well-preserved normal skin histology before and after skin transplantation. Here, we show that cryopreserved NHP skin can be stored for a prolonged time and grafted in a delayed manner. Cryopreserved skin could serve as a source when a living donor NHP is unavailable, including for testing donor-specific tolerance in the absence of the organ donor.