Adipose-derived stem cells regulate CD4+ T-cell-mediated macrophage polarization and fibrosis in fat grafting in a mouse model.

Autologous fat grafting is becoming increasingly common worldly. However, the long-term retention of fat grafting is still unpredictable due to the inevitable fibrosis arising during tissue repair. Fibrosis may be regulated by T-cell immune responses that are influenced by adipose-derived stem cells (ASCs). Therefore, we hypothesized that overly abundant ASCs might promote fibrosis by promoting T-cell immune responses to adipose tissue. We performed 0.3 ml fat grafts with 10/ml, 10/ml and 10/ml ASCs and control group in C57 BL/6 mice . We observed retention, fibrosis, T-cell immunity, and macrophage infiltration over 12 weeks. Besides, CD4+ T-helper 1 (Th1) cells and T-helper 2 (Th2) cells were co-cultured with ASCs or ASCs conditioned media (ASCs-CM) . We detected the ratio of Th2%/Th1%. Results showed that the retention rate was higher in 10 group, while even lower in 10 group with significantly increased inflammation and fibrosis than control group at week 12 . There was no significance between control group and 10 group. Also, 10 group increased the infiltration of M2 macrophages, CD4+ T-cells and Th2/Th1 ratio. , the ratio of Th2%/Th1% induced by ASCs-transwell group was higher than ASCs-CM group and showed concentration-dependent. Accordingly, high concentrations of ASCs in adipose tissue can promote Th1-Th2 shifting, and excessive Th2 cells might promote the persistence of M2 macrophages and increase the level of fibrosis which lead to a decrease in the long-term retention of fat grafts. Also, we found ASCs promoted Th1-Th2 shifting .