Expansion of adipose tissue-derived stromal cells at "physiologic" hypoxia attenuates replicative senescence

Multipotent mesenchymal stromal cells are considered as a perspective tool in cell therapy and regenerative medicine. Unfortunately, autologous cell therapy does not always provide positive outcomes in elder donors, perhaps as a result of the alterations of stem cell compartments. The mechanisms of stem and progenitor cell senescence and the factors engaged are investigated intensively. In present paper, we elucidated the effects of tissue-related O₂ on morphology, functions, and transcriptomic profile of adipose tissue-derived stromal cells (ASCs) in replicative senescence in vitro model. Replicatively senescent ASCs at ambient (20%) O₂ (12-21 passages) demonstrated an increased average cell size, granularity, reactive oxygen species level, including anion superoxide, lysosomal compartment activity, and IL-6 production. Decreased ASC viability and proliferation, as well as the change of more than 10 senescence-associated gene expression were detected (IGF1, CDKN1C, ID1, CCND1, etc). Long-term ASC expansion at low O₂ (5%) revoked in part the replicative senescence-associated alterations.