Effect of age and gender on cell proliferation and cell surface characterization of synovial fat pad derived mesenchymal stem cells

Cell based therapies are being investigated for biological repair of a variety of disorders. Previous work has shown that mesenchymal stem cells (MSCs) from older patients have reduced proliferation rates. As age is associated with greater musculoskeletal morbidity, e.g., osteoarthritis, an optimal MSC expansion strategy is required for older patients. In this in vitro study we investigate how age and gender affect MSC proliferation rate and cell surface characterization, as well as identify a relationship between seeding density and proliferation that could be applied to therapeutic MSC uses. Synovial fat pad derived MSCs were isolated and expanded from 14 patients undergoing total knee replacements. The cells were seeded at densities between 50 and 10,000 cells/cm2 and cell proliferation studies, flow cytometry, and cell surface staining were performed. Females were found to have consistently higher cell proliferation and cell surface marker expression. The cell surface marker CD105 had a constant expression irrespective of age. A statistically significant inverse relationship was found between seeding densities and cell proliferation rates. This study has shown that patient characteristics do effect cell proliferation rate and cell surface characterization, but as seeding density has a significant relationship with proliferation rate, it can be altered, possibly along with other cell culturing strategies, to compensate for the effects of patient factors on MSCs. We have also shown that gender affects cell proliferation and cell surface characterization, something most previous studies may have failed to identify as they group male and female patients together. (C) 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:10131018, 2012