The Effects of Macrophages on the Survival of Random Skin Flaps in Swine

Tissue macrophages play a critical role in neovascularization by releasing angiogenic cytokines. Macrophages normally arrive into a wound bed 48 to 96 hours following an injury.1 Introducing macrophages into a wound bed at the time of closure would theoretically stimulate neovascularization in the traumatized tissue prior to what is normally observed. The ability to promote early angiogenesis could be an important factor in the survival of an extended skin flap. By taking advantage of advanced cell‐sorting techniques, the authors developed the first study to evaluate the effect of placing a purified autologous macrophage population into an extended skin flap. We created 72 dorsally based random skin flaps in Yorkshire pigs; 48 of these wounds received autologous macrophages while 24 flaps served as controls. The macrophages were obtained by utilizing monoclonal antibodies in conjunction with flow cytometry. The skin flaps were evaluated on postoperative day 6 for their viability. Analysis of the data showed no statistically significant difference between the control and treatment flaps. There was, however, a trend of increased survival for flaps treated with macrophages. This is the first study to investigate using a purified population of cells to improve the survival of random skin flaps.