Heating Pretreatment of the Recipient Site Enhances Survival of Transplanted Fat in a Mouse Model

Abstract

Background: Despite several studies about the preparation of the recipient site in fat grafting, optimizing techniques with clinical usefulness is still necessary. Through previous animal studies reporting that heat can increase tissue vascular endothelial growth factor and vascular permeability, the authors hypothesize that pretreatment heating of the recipient site will increase retention of grafted fat.Methods: Twenty 6-week-old female BALB/c mice had two pretreatment sites on their back, one for the experimental temperatures (44 degrees C and 48 degrees C) and the other for the control. A digitally controlled aluminum block was used to apply the contact thermal damage. Human fat (0.5 mL) was grafted on each site and harvested on days 7, 14, and 49. The percentage volume and weight, histologic changes, and peroxisome proliferator-activated receptor gamma expression, a key regulator of adipogenesis, were measured by the water displacement method, light microscopy, and quantitative real-time polymerase chain reaction, respectively.Results: The harvested percentage volumes were 74.0% +/- 3.4%, 82.5% +/- 5.0%, and 67.5% +/- 9.6% for the control, 44 degrees C-pretreatment, and 48 degrees C-pretreatment groups, respectively. The percentage volume and weight of the 44 degrees C-pretreatment group was higher than the other groups (P < 0.05). The 44 degrees C-pretreatment group exhibited significantly higher integrity with fewer cysts and vacuoles than the other groups. Both heating pretreatment groups showed markedly higher rates of vascularity than the control group (P < 0.017), and also increased the expression of peroxisome proliferator-activated receptor gamma over two-fold. Conclusion: Heating preconditioning of the recipient site during fat grafting can increase the retention volume and improve the integrity, which is partly explained by increased adipogenesis in a short-term mouse model. (Plast. Reconstr. Surg. 152: 787, 2023.)