Two-stage face transplantation: a new concept in vascularized composite allotransplantation.

BACKGROUND: Animal models and clinical cases of facial allotransplantation have been performed as a single stage procedure. A staged surgery might offer some advantages in selected cases. In this study, a two-stage face transplantation approach was performed on rat and the feasibility and safety were evaluated. METHODS: Brown Norway rats were used as donors and Lewis rats as recipients in the allotransplantation groups. A total of 33 hemiface-scalp transplantations were performed. Syngeneic orthotopic transplantations were performed either in one-stage (one single stage surgery; N = 3), local two-stage [heterothopic transplantation to the neck during the first stage and graft rotation as a pedicled flap to cover the facial defect on postoperative day (POD) 2; N = 3], or distant two-stage approaches (heterothopic transplantation to the groin during the first stage and free graft transfer to the face on postoperative day 2; N = 3). In the allotransplantation groups using the same approaches, 12 received no treatment (N = 4 each subgroup) and 12 received the same tapering dose of cyclosporine (10 to 2 mg/Kg/day; N = 4 each subgroup). Graft survival and the rejection grades were assessed clinically and pathologically. RESULTS: All syngeneic transplants survived for the follow-up period of 180 days. The mean rejection-free survival and total survival of the allograft in the no treatment group was 6 ± 0.3 and 14.3 ± 4.5 days in the one-stage group, 6 ± 0.4 and 18.5 ± 1 days in the local two-stage group and 6 ± 0.2 and 14.3 ± 5.7 (P > 0.05). All allografts in the treatment groups did not develop rejection during the 42 days follow-up period. CONCLUSIONS: It is feasible, reliable, reproducible, and safe to perform a two-stage face transplantation in rats. This novel approach has the potential to be applied in research and eventually in selected clinical cases of facial allotransplantation.

A novel rat full-thickness hemi-abdominal wall/hindlimb osteomyocutaneous combined flap: influence of allograft mass and vascularized bone marrow content on vascularized composite allograft survival.

Vascularized bone marrow transplantation (VBMT) appears to promote tolerance for vascularized composite allotransplantation (VCA). However, it is unclear whether VBMT is critical for tolerance induction and, if so, whether there is a finite amount of VCA that VBMT can support. We investigated this with a novel VCA combined flap model incorporating full-thickness hemiabdominal wall and hindlimb osteomyocutaneous (HAW/HLOMC) flaps. Effects of allograft mass (AM) and VBMT on VCA outcome were studied by comparing HAW/HLOMC VCAs with fully MHC-mismatched BN donors and Lewis recipients. Control groups did not receive treatments following transplantation. Treatment groups received a short course of cyclosporine A (CsA), antilymphocyte serum, and three doses of adipocyte-derived stem cells (POD 1, 8, and 15). The results showed that all flaps in control allogeneic groups rejected soon after VCAs. Treatment significantly prolonged allograft survival. Three of eight recipients in HLOMC treatment group had allografts survive long-term and developed donor-specific tolerance. Significantly higher peripheral chimerism was observed in HLOMC than other groups. It is concluded that the relative amount of AM to VBMT is a critical factor influencing long-term allograft survival. Accordingly, VBMT content compared with VCA mass may be an important consideration for VCA in humans.