Osteoprogenitors are Enriched following Resveratrol-treatment of Adipose-derived Mesenchymal Cells

Objective: Adipose tissue has been shown to contain a supply of mesenchymal stem cells (MSCs), however improved enrichment techniques are required before these cells can be used effectively. Resveratrol inhibits cyclooxygenase and activates Sirt1, which inhibit adipogenesis and induce apoptosis in adipocytes. This suggested that resveratrol could reduce the number of adipocyte progenitor cells and enrich the MSC population with osteogenic progenitors (OPCs). This study tested the hypothesis that resveratrol enriches MSCs and OPCs through an increase in cell number and percent of total population for both MSCs and OPCs. Methods: Adherent cells were isolated from the inguinal fat pads of Sprague-Dawley rats, plated at 5,000 cells/cm2, and cultured in MSC growth media (GM) or osteogenic media (OM) (Lonza) containing 0, 12.5, or 25µM resveratrol for 7 or 14 days. Flow cytometry was used to assess expression of MSC (CD73+, CD271+, and CD45-) or osteoblast (osteocalcin) markers in the original population as well as following growth in GM or OM. Results: Resveratrol caused a dose and time-dependent increase in cell number and of the percentage of both MSCs and OPCs. In GM containing 25µM resveratrol, there was a 577-fold increase in MSCs at 7 days (5% of population), and a 106-fold increase in OPCs (21% of population) at 14 days. In OM, 25 µM resveratrol increased MSCs 27.8-fold (18% of population) at 7 days, and OPCs 29.9-fold (34% of population) at 14 days. Conclusion: These results show that MSCs and OPCs were present in the original adherent cell population and that resveratrol treatment enriched both cell populations. Resveratrol increased the cell number and the population percentage of MSCs and OPCs. Moreover, effectiveness of the treatment was reduced when the adherent cells were cultured in OM. Supported by Department of Defense; Children's Healthcare of Atlanta; NSF.