Impact of Pretreatment with Tranexamic Acid on Fat Graft Survival.

BACKGROUND: The retention rate after autologous fat grafting is unpredictable and often suboptimal. Tranexamic acid (TXA) is widely used for its hemostatic effects and its ability to attenuate edema and inflammation. However, the effects of TXA on fat graft outcome remain unclear. In this study, TXA-treated fat grafts were transplanted into C57BL/6 mice to evaluate the effects of TXA on graft retention and quality. METHODS: A total of 24 mice were included. Inguinal fat pads were harvested and pretreated with different concentrations of TXA (0 mg/mL [phosphate-buffered saline control], 4 mg/mL, 10 mg/mL, and 50 mg/mL) before subcutaneous transplantation into the same mice. Samples were collected at 10 weeks. Weight retention was measured, and histological analyses were performed using hematoxylin and eosin staining, along with immunohistochemical staining for perilipin and CD31. The effects of TXA pretreatment on fat graft retention and quality, along with its potential underlying mechanisms, were evaluated. RESULTS: At 10 weeks, the weight retention rates were 45.2 ± 5.0% in the control group (0 mg/mL), 52.3 ± 4.3% in the 4 mg/mL TXA group, 54.7 ± 3.5% in the 10 mg/mL TXA group, and 55.0 ± 4.6% in the 50 mg/mL TXA group. Statistical analysis demonstrated that all TXA-treated groups exhibited significantly higher graft retention than the control group, whereas no significant differences were observed among the TXA-treated groups. Histologic evaluation demonstrated improved adipocyte structural integrity in the TXA-treated groups compared with the control group. Perilipin immunohistochemical staining further revealed significantly greater adipocyte viability in the TXA-treated groups, whereas CD31 staining showed comparable vascularity among all groups. CONCLUSIONS: TXA pretreatment improved fat graft retention and adipocyte viability in a murine fat grafting model. Notably, increasing TXA concentrations beyond 4 mg/mL did not provide additional benefits, suggesting that relatively low-dose TXA may be sufficient to improve graft outcomes. Because vascularity did not differ significantly among groups, the beneficial effects of TXA may be more closely related to preservation of the local graft microenvironment rather than promotion of angiogenesis. Further mechanistic and randomized controlled studies are warranted to validate these findings. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .