Influence of flap prefabrication on seeding of subcutaneously injected mesenchymal stem cells in microvascular beds in rats.

Background: In this article, the authors investigated whether the prefabrication of an autologous pedicled flap by isolation from the surrounding with artificial skin substitutes would increase mesenchymal stem cell (MSC) seeding. Methods: Mesenchymal stem cells were isolated from human umbilical cords and were cultured and characterized by f luorescence-activated cell sorting. Oxacarbocyanine and its green f luorescence emission were used to label the MSCs population. Sixteen adult Wistar rats were randomized in 4 groups (n = 4 animals per group). In group 1, a prefabricated groin flap (GF) with skin substitutes was harvested without cell injection; in group 2, 1 million MSCs were injected subcutaneously in the area corresponding to the GF without flap harvesting; in Group 3, a prefabricated GF with skin substitutes was harvested and 1 million MSCs were injected subcutaneously; and in Group 4, a prefabricated GF with skin substitutes was harvested and 2 million MSCs were injected subcutaneously. All procedures were performed bilaterally in each animal. Animals were sacrificed 2 weeks after the surgery. Flap viability was then assessed by clinical inspection and histology, and seeding of MSCs was observed. Results: All flaps survived 2 weeks after the surgery. Oxacarbocyanine-labeled cells were found in all prefabricated flaps injected (Groups 3 and 4) in higher number in comparison with the group where subcutaneous injection without flap harvesting was performed (Group 2). This difference was statistically significant (P G 0.05). Conclusions: Prefabricated skin f laps with skin substitutes may provide a useful vehicle for the implantation of MSCs to serve as an autologous microvascular bioscaffold.