Comparative Analysis of Viability, Regeneration, and Functional Contributions of Cryopreserved Adipose-Derived...

Fat grafting is widely used in reconstructive and aesthetic surgery, but outcomes can vary due to inconsistent fat survival. Cryopreservation offers a way to store excess adipose tissue, potentially reducing the need for repeated harvesting. However, the impact of cryopreservation on the viability and functionality of adipose tissue components remains unclear.

This study evaluated the survival, regenerative potential, and biological contributions of cryopreserved adipose-derived stem cells (ADSCs), stromal vascular fraction (SVF), fat graft, and tissue cocktail in a rat model.

Inguinal fats harvested from 48 immunocompetent male Wistar rats were processed into ADSCs, SVF, fat graft, and tissue cocktail. These components underwent a standardized cryopreservation protocol for 3 months, followed by autologous transplantation into the contralateral inguinal fat. Histological, immunohistochemical, and morphological evaluations assessed tissue viability, angiogenesis, and adipogenesis at 4 and 8 weeks to evaluate the components' behavior as grafts.

ADSCs and SVF groups demonstrated superior regenerative potential, as evidenced by significant weight increase in the ADSCs-SVF group at weeks 4 and 8 (P = 0.037, Cohen's d = 1.79), indicating progressive tissue remodeling and active growth. VEGF expression was significantly elevated in the ADSCs, SVF, and ADSCs-SVF groups compared to controls (P < 0.05), with enhanced adipogenesis and angiogenesis confirmed histologically. Inflammatory response, edema, and fibrosis were significantly reduced in these groups (P < 0.001), and no necrosis was observed. In contrast, the fat graft and tissue cocktail groups exhibited severe inflammation, increased necrosis, and giant cell accumulation, despite displaying the highest VEGF and Ki67 expression (P < 0.001), suggesting prolonged and severe inflammation that can lead to dysfunction.

Cryopreserved ADSCs and SVF are superior adipose-derived components for repeat fat grafting procedures. They preserve graft volume and significantly promote angiogenesis and adipogenesis while minimizing inflammation and tissue damage. These findings support their potential for enhancing long-term graft survival and tissue regeneration in clinical applications.