VASCULARIZED BONE MARROW TRANSPLANTATION: AN ALTERNATIVE TO CONVENTIONAL CELLULAR BONE MARROW TRANSPLANTATION

Dragos Zamfirescu¹, Ioan Lascar¹, Ion Zegrea¹, Marius Popescu¹, Corina Popoviciu¹, Mihail Climov², Marco Lanzetta^3,4.

¹Plastic Surgery and Reconstructive Microsurgery Clinic, “Carol Davila” Bucharest Medical University, Bucharest, Romania; ²Harvard Medical School; ³Italian Institute for Hand Surgery and Microsurgery, Monza, Milan, Italy; ⁴University of Canberra, Australia.

Background: Current protocols for bone marrow transplantation (BMT) involve removing the bone marrow component directly from its donor microenvironment and then injecting such components into the circulatory system of the recipient. This procedure is usually preceded by conditioning protocols (body irradiation, immunosuppression, or both). Vascularized bone marrow transplantation (VBMT), in comparison with conventional marrow transplants, has the advantage of providing a microenvironment and immediate engraftment of both mature and progenitor hemopoietic cells at the time of transplantation in the absence of immunomodulation or irradiation. The aim of the study was to follow the development of microchimerism after allogeneic VBMT vs conventional BMT.

Methods: In one group a VBMT model consisted of a donor Brown Norway (BN) rat hind limb heterotopic transplanted on recipient Lewis rats was used. An intravenous infusion of donor bone marrow cells in suspension equivalent to that grafted in the vascularized femur limb was administrated i.v. on recipient rats in the second group. Cellular microchimerism was investigated in recipients of VBMT vs BMT.

Results: Donor-derived cells could be detected in VBMT recipients at 30 and 60 days but not in recipients of i.v. suspension BMC grafting.

Conclusions: VBMT provides a theoretical alternative to conventional cellular bone marrow transplantation by addressing crucial clinical problems such as failure of engraftment or graft versus host disease. It may be possible to develop a new approach for bone marrow transplantation based primarily on a microsurgical procedure (transplantation of vascularized bone marrow flaps).