Adipose-Derived Stem Cells Improve Survival of Random Pattern Cutaneous Flaps in Radiation Damaged Skin

Tissue ischemia and necrosis following surgery after radiotherapy on the skin and subcutaneous tissue are well known to all reconstructive surgeons. Nevertheless, there has been no report so far on local effects of adipose-derived stem cells (ADSCs) on random flap survival elevated in an irradiated rat dorsum. In this experimental study, we aimed to identify the effect of adipose tissue-derived stem cell injection on random flap survival in irradiated tissues.

Adipose-derived stem cells were isolated from the groin region of Sprague-Dawley rats and expanded ex vivo for 3 passages. Animals were divided into 2: irradiated and nonirradiated and then again into ADSC injected and noninjected groups altogether 4 groups. After elevation of caudally based dorsal random skin flaps (10  cm long and 3  cm wide), Green fluorescent protein labeled ADSCs were then injected to the base of the pedicle. Radiotherapy was 20  Gy single dose applied during 8 weeks before surgery. At postoperative day 7, flap viability measurement and tissue harvest for histologic and immunocytochemical assessment were performed in all groups.

We have observed increased flap viability in ADSCs injected irradiated group compared with control radiation group with small but not statistically significantly increase in vessel count per field. Mean survival rate of the flaps in groups A, B, C, and D were 40.46%, 60.07%, 40.90%, and 56.13%, respectively. There was a statistically significant vessel count difference between group B and group A and also with group D (P < 0.001).

These findings suggest that ADSCs have a potential for enhancing the blood supply of random pattern skin flaps after radiation injury. This mechanism might be both neovascularization and vasodilation along with endothelial repair. Further studies are needed.