Abstract 15911: Reduced Senescence and Enhanced Proliferation of Human Cardiac Progenitor Cells Isolated and Expanded Under Reduced Oxygen Tension

• Published in: Circulation (New York, N.Y.) N.Y.), 2015-11, Vol.132 (Suppl_3 Suppl 3), p.A15911-A15911
• Main Authors: He, Huamei, Xiong, Hui, O’Malley, Thomas, Ji, Beisi, Favre, Elizabeth G, McGowan, Francis X
• Format: Article
• Language: English
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/circ.132.suppl_3.15911

BackgroundOxygen availability at the cellular level in vivo is significantly lower (~1-7%) than that used for typical ambient cell culture conditions (21%). Here we investigated whether prolonged culture at reduced O2 concentrations affected proliferation, senescence and oxidative stress of human cardiac progenitor cells (hCPCs).MethodshCPCs positive for c-kit and negative for lineage markers (ckit+/Lin-) were isolated from right atrial tissues obtained from five infants during repair of congenital heart defects and expanded for a maximum of 10 passages in varying O2 concentrations (1, 5, and 21%); all manipulations were performed at the target O2 in a hypoxic chamber. Cellular phenotype was confirmed by ICC staining and flow cytometry. Doubling time, oxidative stress (8-OH-deoxyguanosine [8OHdG], protein carbonyl formation) and senescence markers (telomere length, telomerase activity, P16ink4a staining) were measured.ResultsReducing ambient O2 from 21% to 1% did not alter cell surface marker expression. Culture and expansion at 21% O2 markedly accelerated hCPC senescence compared to 1% or 5% O2, as indicated by increased P16ink4a positive hCPCs and greater loss of telomere length and telomerase activity; much of this damage appeared to occur during early passage and expansion. Both protein carbonyl and 8OHdG formation progressively increased in 21% O2, whereas these oxidative injury markers showed little change at 1 and 5% O2 concentrations. hCPCs that were cultured at either 5% or 1% O2 demonstrated shorter doubling times with resultant higher cell yields during in vitro expansion.ConclusionCulturing ckit+/Lin- hCPCs at lower oxygen tension minimizes oxidative damage, reduces senescence, and enhances proliferative potential during long-term culture; expansion at 1% ambient O2 appeared to be most effective. This relatively straightforward modification may further understanding of the biology of CPCs and their regenerative potential.