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

To confirm in pigs whether a new method for organ allografts, originally established in mice by the authors, might be applicable to humans.

The authors recently established a new method for organ allografts in mice that includes the injection of donor bone marrow cells (BMCs) using the portal vein (PV), followed by the administration of cyclosporin A (CsA) on days 2 and 5, and the intravenous injection of BMCs on day 5. In the present study, they modify this method (a single-day protocol) and apply it to pigs.

Allogeneic BMCs of donor pigs were injected using the PV (a superior mesenteric vein). The skin grafting was carried out on the day of the PV injection. The recipient pigs received donor grafts, autologous grafts, and third-party grafts at the same time. In addition, an open wound was made as the epithelized control. Full-thickness skin grafts were harvested from the dorsal wall of the donors. CsA (10 mg/kg) was injected intramuscularly into recipient pigs on days 2 and 5 after the PV injection.

One hundred percent of skin grafts survived for >300 days when donor BMCs were injected using the PV (n = 6). However, the skin grafts of the three pigs that had received BMCs using the intravenous route were rejected within 3 to 4 weeks after transplantation. The third-party skin grafts showed necrotic changes on day 21 after transplantation.

One hundred percent of skin allografts can be obtained, even in pigs, by injecting donor BMCs using the PV, carrying out skin allografts, and administering CsA on days 2 and 5. This single-day protocol would be of great advantage for human organ transplantation.