Enhancement of viability of fat grafts in nude mice by endothelial progenitor cells

BACKGROUND A recent discovery showed that endothelial progenitor cells (EPCs) could augment collateral vessel growth to ischemic tissues. OBJECTIVE The objective was to demonstrate the effects of EPCs on the vasculogenesis and survival of free transplanted fat tissues in nude mice. METHODS EPCs from human donors were cultured in vitro for 7 days. Human fat tissues were injected subcutaneously into the scalps of 20 6-week-old nude male mice. EPCs stained with CM-DiI were mixed with the transplanted fat tissues and injected into the mice. EBM-2 medium was used as control group. The animals were euthanized 15 weeks after the procedure. Graft volume were measured, and histologic evaluation was performed. The central part of fat tissues was histologically evaluated 15 weeks after the fat injection. RESULTS The survival volume of the experimental group was significantly greater than that of the control group (p <.05). Less cyst formation and fibrosis was obtained in the experimental group. Histologic evaluation of the central part of fat tissues 15 weeks after the fat injection showed that capillary densities increased markedly in the experimental group mice. CONCLUSION The results indicate that EPCs have the ability to enhance the survival and the quality of the transplanted fat tissues.