4. Investigating the Influence of Tranexamic Acid on Adipocyte Differentiation in an In Vitro Model

PURPOSE: Tranexamic acid (TXA) is gaining momentum in plastic surgery, particularly for its use in the tumescent fluid during liposuction. It is reported to reduce blood loss and hematoma formation therefore promising a smoother postoperative recovery. For patients undergoing fat grafting procedures that use the TXA containing lipoaspirate, despite the surge in its application, the cellular effects of TXA on fat grafts have not been directly investigated. Our research endeavors to elucidate this gap by employing an in vitro model, focusing on the impact of TXA injections on the differentiation trajectory of mesenchymal progenitor cells towards adipocytes. METHODS: Adipose tissue explants from abdominal panniculectomy were cultured in a 3D system with various TXA concentrations (Vehicle, 5µg/mL, 10µg/mL). After 14 days, Human Adipose Capillary Associated Progenitor Cells (HACAPs) were isolated and cultivated in 2D cultures, maintaining the TXA concentrations. The growth rate of HACAPs was assessed through two expansions. Subsequently, cells underwent adipogenic differentiation for 10 days using media enriched with insulin, dexamethasone, and 3-Isobutyl-1-methylxanthine (MDI). Three states were maintained: undifferentiated (C), MDI-differentiated (M), and a set exposed to MDI and Forskolin (F), an activator promoting thermogenesis. The effects of TXA on HACAPs’ differentiation and thermogenesis were analyzed using rt-qPCR for gene expression and lipid droplet imaging in differentiated cells. RESULTS: When compared to the vehicle treated controls, capillary sprouting was similar in the TXA treated explants. Furthermore, all cell yields and growth rates throughout two expansions were equivalent in the three groups. No differences were observed in cell morphology or lipid droplet accumulation when treated with media to induce adipogenesis (MDI) and imaged under brightfield microscopy. Additionally, gene expression profiles show similar expression of the adipogenic genes Adiponectin (AdipoQ), Perilipin 1 (PLIN1), and Fatty Acid Binding protein 4 (FABP4) following 10 days of differentiation. Upon thermogenic activation with a 6 hour exposure to 10µM forskolin, expression of the thermogenic genes Uncoupling Protein 1 (UCP1), Long noncoding RNA 473 (LINC473), and Deiodinase 2 (DIO2) were similar in all groups. CONCLUSION: Our study indicates that TXA does not significantly alter the differentiation of mesenchymal progenitors in fat grafting. Given the growing use of TXA in plastic surgery, this consistency in cellular response is reassuring and suggests that TXA is not a detrimental additive to tumescent solutions for patients undergoing fat grafting.