Effect of adipose-derived mesenchymal stem cells on the viability of the transverse rectus abdominis myocutaneous flap in rats

Introduction: The Transverse Rectus Abdominis Myocutaneous (TRAM) flap is used for breast reconstruction, but involves the risk of necrosis. Adipose tissue-derived mesenchymal Stem Cells (ADSCs) can be used to stimulate neovascularization and reduce the risk of TRAM flap necrosis. Aim: Determine the effect of ADSCs on TRAM flap viability in rats. Methods: Twenty-four Wistar-EPM rats were distributed into three groups (n = 8). A right caudal pedicled TRAM flap was performed in all the animals and was the only procedure performed in Group TRAM. The additional procedures of intradermal injection of alpha-MEM culture medium and intradermal injection of alpha-MEM containing ADSCs labeled with a fluorescent marker were performed in Groups alpha-MEM and alpha-MEM-SC, respectively. The percentage of flap necrosis was determined, and the level of neovascularization and distribution of stem cells in the TRAM flap was assessed using immunohistochemical analysis and fluorescence microscopy, respectively. Results: The percentage of necrosis observed in Group alpha-MEM-SC was lower than that observed in Groups TRAM and alpha-MEM, namely 23.36 % vs. 50.42 % and 53.57 %, respectively (p < 0.05). In Zone IV of the flap, the number of vessels was greater in Group alpha-MEM-SC than in the other groups (p < 0.05). Multiple stem cells were observed in the four zones of the flap in Group alpha-MEM-SC. No stem cells were observed in Groups TRAM or alpha-MEM. Conclusion: ADSCs increased TRAM flap viability and the number of vessels in Zone IV of the flap in rats.