Many cross-sectional studies have tried to assess the in vivo effect of oxidative stress on organismal aging in general and on telomere length dynamics specifically. Here we followed telomere length dynamics over a 12-month interval, in divers exposed to intense hyperbaric oxygen in comparison with an age-matched control group. Both groups were exposed to extreme physical activity, as well. Among the divers following the oxidative stress, significant telomere elongation was observed in granulocytes and naïve T cells, but not in memory T cells and B cells. Telomere length in granulocytes was mildly elongated in the control group as well, a finding that may relate to the extreme physical activity to which they were exposed. While telomere elongation in naïve T cells may be attributed to telomerase activation, we suggest that in granulocytes the elongation results from undifferentiated hematopoietic cells carrying longer telomeres that repopulate the peripheral hematopoietic compartment. This event might be accompanied by enhanced cell division within the repopulating pool. Since the aging of mammalian tissues can be attributed in part to the reduction in the replicative potential of self renewing cells, enhanced cell turnover under conditions of hyperbaric oxidative stress might be directly relevant to tissue and organismal aging.
Bibliographical noteFunding Information:
This research was supported by the Israel Science Foundation (grant No. 542/05 ) (S.S.), Deborah Fund (K.S., S.S., L.S.), Israel Defense Force Medical Corps and Israeli MOD (L.S.), Canadian Institutes of Health Research ( MOP38075 and GMH79042 ) (P.M.L.) and the National Cancer Institute of Canada (with support from the Terry Fox Run) (P.M.L.).
- Hematopoietic stem cells
- Oxidative stress
- Oxygen divers
- Telomere length