Qualitative analysis of the viability of autogenous fat grafts grafted in different environments of interstitial pressure. Preliminary results and description of a new experimental model in mini-pigs

Purpose: To evaluate the feasibility of an experimental model of autologous fat graft (AFG) in different interstitial pressure (IP) environments. Methods: Three mini-pigs(Minipig-BR) with age of 8 months (weight: 25-30 kg) were used. AFG were collected from the bucal fat pad, and grafted in the intramuscular pocket (biceps femoralis muscle). IP model was based on a fusiform ressection followed by primary closure “under tension”. A blood pressure catheter located in the intramuscular region connected to a pressure module was applied to quantify IP. Results: The mean operative time was 236 min (210 - 272 min). All the AFG and muscular segments were removed successfully. Average interstitial pressure CP and H were 3 and 10.6 mmHg respectively. The AFG were biopsied for histopathological analysis 30 days after graft. Hematoxylin-eosin staining and immunohistochemical analyzes (TNF-alpha, CD31 and Perilipine with monoclonal antibodies) were employed. Conclusion: The data show that minipigs model could be used as a recipient site for autologous fat graft techniques and allow the development of studies to explore the AFG intake and pathophysiology response.