[abstract] HEAT SHOCK PROTEIN 70 IS UPREGULATED IN BLOOD LEUKOCYTES FROM EXPERIENCED DIVERS IN RESPONSE TO REPETITIVE HYPERBARIC STRESS.

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[abstract] HEAT SHOCK PROTEIN 70 IS UPREGULATED IN BLOOD LEUKOCYTES FROM EXPERIENCED DIVERS IN RESPONSE TO REPETITIVE HYPERBARIC STRESS.

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Title: [abstract] HEAT SHOCK PROTEIN 70 IS UPREGULATED IN BLOOD LEUKOCYTES FROM EXPERIENCED DIVERS IN RESPONSE TO REPETITIVE HYPERBARIC STRESS.
Author: Rhind, SG; Cameron, BA; Eaton, DJ
Abstract: BACKGROUND: Heat shock proteins (HSPs) are upregulated in blood leukocytes following exposure to various physiological stressors, including hyperthermia, exercise, and hypoxia. Limited human studies indicate that acute hyperbaric stress enhances HSP70 expression and animal data suggest that prior induction of HSP70 may be protective against decompression sickness (DCS). However, the effect of repeated hyperbaric stress on HSP70 expression has not been investigated in humans. The aim of this study was to examine the impact of 3 consecutive days of hyperbaric stress on intracellular (i)HSP70 expression in human leukocyte subsets. MATERIALS AND METHODS: Eight experienced male divers (21-55 yr) underwent 3 dry simulated dives to 450 kPa (45 msw) for 35 min in a hyperbaric chamber over a 3-d period. Venous blood samples were drawn under basal conditions pre-dive and immediately after exposure (post- dive). Multi-color flow cytometry was used to quantify spontaneous and in vitro heat-shock (42 ºC, 1h) induced iHSP70 expression by lymphocytes, monocytes and neutrophils; results are expressed as the % and median fluorescence intensity (MdFI) of each subset. RESULTS: Compared to pre-dive levels, iHSP70 expression was incrementally upregulated after repeated hyperbaric exposures, with peak increases (p < .001) observed in monocytes and neutrophils post-dive-3. Hyperbaric stress elicited 3- and 7-fold increases (p < .001) in the spontaneous % of monocytes and neutrophils expressing iHSP70, respectively. Corresponding increases in iHSP70 MdFI by neutrophils (14.4 ± 0.3 to 25.0 ± 3.0; p < .01) and monocytes (9.9 ± 0.2 to 16.4 ± 1.1; p < .01) were observed post-dive-3. Relative to spontaneous levels, heat shock augmented pre-dive leukocyte iHSP70 expression and further enhanced post-dive iHSP70 by monocytes and neutrophils. CONCLUSIONS: This study demonstrates that HSP70 expression is upregulated in humans exposed to repetitive episodes of hyperbaric stress. The results suggest that HSP70 induction is a cellular adaptation to recurrent diving, which may contribute to diving acclimatization and a reduced susceptibility to DCS in individuals undergoing chronic hyperbaric stress.
Description: Abstract of the Undersea and Hyperbaric Medical Society, Inc. Annual Scientific Meeting held June 14-16, 2007. Ritz-Carlton Kapalua Maui, Hawaii (http:www.uhms.org)
URI: http://archive.rubicon-foundation.org/5192
Date: 2007

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  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

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