Transplantation of adipose stromal cells promotes neovascularization of random skin flaps.

The delivery of bone marrow-derived mononulear cells (BM-MNCs) has been proved to be effective at promoting neovascularization of ischemic skin flaps. However, the limited source of BM-MNCs restricts their clinical application. Stromal vascular fraction (SVF) contains a group of heterogeneous cells in the adipose tissue, including adipose tissue-derived stem cells, and it has abundant reserve in human body. In this study, we evaluated the therapeutic potential of SVF to promote neovascularization of random skin flaps. Female Wistar rats were randomly devided into three groups with 8 in each group and received allogeneic SVF, BM-MNCs and phosphate-buffered saline (PBS), respectively, before surgery. Two days after cell administration, a 10 × 3 cm random skin flap was elevated. Flap survival, blood flow perfusion and capillary density were examined 7 days after surgery, and the relevant mechanism was also explored. Results showed that SVF group and BM-MNCs group had higher survival percentage (72.2 ± 2.0% and 76.4 ± 3.1%, respectively) as compared with the control group (56.8 ± 4.6%, P < 0.05). Blood flow perfusion and capillary density of flap tissues in SVF and BM-MNCs groups were both improved. The expression levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were increased in flap tissues of SVF and BM-MNCs groups detected by ELISA. These results indicate that SVF could promote vascularization and increase flap survival probably by secreting VEGF and bFGF. The effect of transplantation of SVF on therapeutic angiogenesis of skin flaps is equivalent to that of BM-MNCs.