Suspension cultures of bone-marrow-derived mesenchymal stem cells: effects of donor age and glucose level

Both ageing and diabetes are associated with reduced numbers and functional viability of mesenchymal stem cells (MSCs) 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 selfrenewal of rat nonadherent bone marrow MSCs (Na-BM-MSCs) in suspension cultures. MSC cultures isolated from 3- and 12-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, colony forming unit-fibroblastic (CFU-f) numbers, and pluripotency characteristics of these cells were determined. This study indicates that rat adult bone marrow harbors pluripotent Na-BM-MSCs that seem to be unaffected by ageing during in vitro expansion. The Na-BM-MSCs 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-MSCs in suspension culture was not reduced in the older animals. The Na-BM-MSCs were found to express the pluripotency markers Oct4, Sox2, and Nanog, suggesting a more primitive stage of differentiation as compared with adherent MSCs. These data indicate that rat adult bone marrow harbors a population of pluripotent Na-BM-MSCs that appear to be relatively unaffected by ageing during in vitro expansion in suspension. © 2012 Mary Ann Liebert, Inc.