Acceptance of skin allografts in pigs by portal venous injection of donor bone marrow cells

Objective To confirm in pigs whether a new method for organ allografts, originally es tablished in mice by the authors, might be applicable to humans. Summary Background Data The authors recently established a new method for organ allografts in mice that includes the injection of donor bone marrow cells (BMCs) using the por tal vein (PV), followed by the administration of cyclosporin A (CsA) on day s 2 and 5, and the intravenous injection of BMCs on day 5. In the present s tudy, they modify this method (a single-day protocol) and apply it to pigs. Methods Allogeneic BMCs of donor pigs were injected using the PV (a superior mesent eric vein). The skin grafting was carried out on the day of the PV injectio n. The recipient pigs received donor grafts, autologous grafts, and third-p arty grafts at the same time. In addition, an open wound was made as the ep ithelized control. Full-thickness skin grafts were harvested from the dorsa l wall of the donors. CsA (10 mg/kg) was injected intramuscularly into reci pient pigs on days 2 and 5 after the PV injection. Results One hundred percent of skin grafts survived for >300 days when donor BMCs w ere injected using the PV (n = 6). However, the skin grafts of the three pi gs that had received BMCs using the intravenous route were rejected within 3 to 4 weeks after transplantation. The third-party skin grafts showed necr otic changes on day 21 after transplantation. Conclusions One hundred percent of skin allografts can be obtained, even in pigs, by in jecting donor BMCs using the PV, carrying out skin allografts, and administ ering CsA on days 2 and 5. This single-day protocol would be of great advan tage for human organ transplantation.