A Simple Method to Determine the Purity of Adipose-Derived Stem Cell-Based Cell Therapies

摘要

It is important to standardize methods to quantify the purity of adipose tissue-derived cells for regenerative medicine. We developed a simple and robust tool to discriminate fibroblasts and adipose stem cells (ASCs) by testing release of specific growth factors. ASCs and dermal fibroblasts (DFs) were isolated from human donors (n = 8). At passage 4, cultures were prepared with progressive ASC/DF ratios of 100%/0%, 75%/25%, 50%/50%, 25%/75%, and 0%/100% for each donor and incubated in hypoxic chambers at 0.1% and 5% O-2 and hyperglycemia at 1.0 and 4.5 g/l. After incubation for 24 hours, cell survival, proliferation, and growth factor release (vascular endothelial growth factor [VEGF], hepatocyte growth factor [HGF], insulin-like growth factor 1 [IGF-1], stromal cell-derived factor 1 alpha [SDF-1 alpha], and basic fibroblast growth factor [bFGF]) were assessed for each condition. The proliferation and viability of ASCs and DFs were not impacted by the oxygen tension conditions. No significant difference in HGF, IGF-1, bFGF, and keratinocyte growth factor secretome was found across the various ASC/DF ratios. Interestingly, a negative relation for VEGF secretion was found when ASCs were contaminated by fibroblasts, especially when cells were exposed to 4.5 g/l glucose and 0.1% O-2 (R = -0.521; p <.001). In contrast, secretion of SDF-1 alpha was positively correlated with the fibroblast ratio, more prominently in low glucose and low oxygen tension (r=.657; p <.001). Above and beyond these previously unreported metabolic features, these results (a) allow us to discriminate fibroblasts and ASCs specifically and (b) allow new tools be developed for the rapid testing (a response within 24 hours) for the release of ASC-based therapies.