Orbital volume augmentation after injection of human orbital adipose-derived stem cells in rabbits

This randomized, controlled animal study investigated the morphologic and histologic properties of rabbit orbital fat following injection of human orbital adipose-derived stem cells (hoADSCs). The efficacy of hoADSCs was compared to that of hyaluronic acid gel (HAG) and human orbital stromal vascular fraction (hoSVF). A total of 30 orbits from 15 New Zealand white rabbits (25 weeks postnatal, 2500-3000 g) underwent injection with HAG (molecular weight [MW] 1,000,000, 0.5 mL, n = 10, HAG only), hoSVF (0.25 mL) mixed with HAG (0.25 mL, n = 10, HAG + hoSVF), or hoADSCs (0.25 mL) mixed with HAG (0.25 mL, n = 10, HAG + hoADSCs). The degree of proptosis, and the time course of changes were determined and compared among groups. The difference between the initial exophthalmometric value and that at 4 weeks after injection was 1.77 mm for HAG only and 2.01 mm for HAG + hoSVF. The difference between the initial value and that at 12 weeks decreased to 0.05 mm for HAG only and 0.24 mm for HAG + hoSVF. In contrast, injection of HAG + hoADSCs increased the exophthalmometric value by 2.43 mm at 4 weeks after injection, and this difference was maintained at 2.56 mm at 12 weeks. Histopathologic examination revealed specific inflammation around the injection materials at 4 weeks after injection, and inflammation subsided 8 weeks after injection in all three groups. Thus, transplantation of hoADSCs with HAG is a safe and effective technique for orbital fat volume expansion. This is a new and promising method for orbital reconstruction and aesthetic orbital volume augmentation.