Gelatin positively regulates the immunosuppressive capabilities of adipose-derived mesenchymal stem cells

The characteristics of adipose-derived mesenchymal stem cells (Ad-MSCs) can be selectively enhanced by altering the culture environment. We evaluated the effects of gelatin on Ad-MSCs when used in combination with culture media. Ad-MSCs were initially cultured in 0%, 0.5%, 1%, 2%, and 4% gelatin in Dulbecco's modified Eagle's medium (DMEM) to evaluate cell proliferation. The expression of inflammatory, antiinflammatory, antioxidant, and osteogenic markers was then assessed by rtPCR in Ad-MSCs cultured in 0.5% gelatin in DMEM (GMSCs), and without gelatin (MSCs), for 5 and 10 days. We found that 0.5% gelatin significantly increased the proliferation rate of Ad-MSCs after 24 h of incubation, up until 72 h. GMSCs had upregulated IL-10, VEGF, and HO-1 after 5 and 10 days of incubation, while IL-6 and TNF-alpha were upregulated after 5 days and then significantly decreased after 10 days of incubation. The osteogenic factors BMP-7, AXIN, and beta-catenin were significantly upregulated in GMSCs after 5 and 10 days. Notably, there was 5-to 8-fold higher expression of BMP-7 in GMSCs than in MSCs. We conclude that culture medium containing 0.5% gelatin enhances the proliferation rate, induces immunosuppression, and activates BMP-7 and the wnt/AXIN/beta-catenin pathway in Ad-MSCs.