109. Vitamin E Treated Fat Grafts Maintain Volume to Improve Grafting Effects on Radiation-induced Fibrosis

Abstract

Introduction: Fat grafts and vitamin E administration have both previously been described to mitigate radiation-induced skin fibrosis. Fat graft retention continues to hinder its long-term functionality affected mainly by two factors: initial inflammatory response and chronic necrosis secondary to hypovascularity. Thus, we aimed to simultaneously improve fat graft retention along with radiation-induced fibrosis. Methods: Ten adult CD-1 nude male mice at 6-8 weeks of age underwent scalp irradiation with 5 Gy every other day for 12 days, totaling in 30 Gy. Mice recovered for four weeks to allow chronic fibrosis to develop. After recovery, mice received 1000μL of donor human fat graft to the scalp. Mice were separated into 4 conditions: ungrafted irradiated, untreated fat graft, fat graft treated with pentoxifylline (PTX), fat graft treated with vitamin E (VE). Fat graft volume retention was monitored in-vivo using microCT scans with 3-dimensional reconstruction and analysis at weeks 0, 1, 2, 4, 6, and 8 after grafting. Fat graft and overlying skin were harvested and underwent histological and cytokine analysis. Results: Histological analysis demonstrated improvement in radiation-induced fibrosis, CD31+ expression, and 8-isoprostane expression in the vitamin E group. Cytokine analysis revealed decreased cell differentiation markers and inflammatory markers. Fat graft volume retention significantly improved as early as 1 week post-grafting with local vitamin E administration compared to control. Conclusion: Radiation-induced fibrosis and fat graft volume retention are both simultaneously improved with novel, local administration of vitamin E, improving both cosmesis and functionality of fat grafting in chronically irradiated fields.