Suspension cultures of bone-marrow-derived mesenchymal stem cells

Both ageing and diabetes are associated with reduced numbers and functional viability of mesenchymal stem cells in vivo which in turn lead to degenerative pathologies of the musculoskeletal system. The overall aim of this study was to elucidate the effects of age and raised glucose levels on the proliferation and self-renewal of rat non-adherent bone marrow MSC (Na-BM-MSC) in suspension cultures. MSC cultures isolated from three month and twelve month old rats were maintained using the "pour off" method for up to 14 days in media containing different glucose levels and the phenotype, growth characteristics, CFU-f numbers and pluripotency characteristics of these cells determined. This study indicates that rat adult bone marrow harbours pluripotent Na-BM-MSCs which seem to be unaffected by ageing during in vitro expansion. The Na-BM-MSC express the pluripotency markers Oct4, Sox2 and Nanog. It was found that culture in high glucose-containing medium had a negative effect on colony formation and differentiation. In contrast to classical MSC cultures, the generation of colonies by Na-BM-MSC in suspension culture was not reduced in the older animals. The Na-BM-MSC were found to express the pluripotency markers Oct4, Sox2 and Nanog suggesting a more primitive stage of differentiation as compared to adherent MSC. These data indicates that rat adult bone marrow harbours a population of pluripotent Na-BM-MSCs which appear to be relatively unaffected by ageing during in vitro expansion in suspension.