Impact of hypoxia and long-term cultivation on the genomic stability and mitochondrial performance of ex vivo expanded human stem/stromal cells

► Human stem/stromal cells were expanded ex vivo under normoxia and hypoxia. ► Hypoxia down‐regulates DNA repair genes and promotes genomic instability. ► Hypoxia and prolonged passaging affect telomere length and mtDNA performance. ► Neither hypoxia nor prolonged passaging affect the integrity of mtDNA. ► Adipose-derived stromal cells react slower to hypoxia than bone-marrow stromal cells.