title: Telomere elongation followed by telomere length reduction, in leukocytes from divers exposed to intense oxidative stress--implications for tissue and organismal aging.
abstract: 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.
authors.affiliation: Laboratory of Molecular Medicine, Rambam Health Care Center and Rappaport Faculty of Medicine and Research Institute, Technion, Haifa, Israel.
authors.forename: Liran I
authors.initials: LI
authors.lastname: Shlush
authors.forename: Karl L
authors.initials: KL
authors.lastname: Skorecki
authors.forename: Shalev
authors.initials: S
authors.lastname: Itzkovitz
authors.forename: Shiran
authors.initials: S
authors.lastname: Yehezkel
authors.forename: Yardena
authors.initials: Y
authors.lastname: Segev
authors.forename: Hofit
authors.initials: H
authors.lastname: Shachar
authors.forename: Ron
authors.initials: R
authors.lastname: Berkovitz
authors.forename: Yochai
authors.initials: Y
authors.lastname: Adir
authors.forename: Irma
authors.initials: I
authors.lastname: Vulto
authors.forename: Peter M
authors.initials: PM
authors.lastname: Lansdorp
authors.forename: Sara
authors.initials: S
authors.lastname: Selig
mesh_terms: D000328:Adult; D000375:Aging / Q000378:metabolism*; D015331:Cohort Studies; D004242:Diving; D004789:Enzyme Activation; D006801:Humans; D007962:Leukocytes / Q000378:metabolism*; D008297:Male; D018384:Oxidative Stress; D019098:Telomerase / Q000378:metabolism; D016615:Telomere / Q000378:metabolism*
chemical_list: D019098:Telomerase