Natural Killer Cells as Biomarkers of Hyperbaric Stress During a Dry Heliox Saturation Dive

Aarhus University Hospital, Aarhus, Central Jutland, Denmark
Aviation Space and Environmental Medicine (Impact Factor: 0.88). 05/2010; 81(5):467-74. DOI: 10.3357/ASEM.2528.2010
Source: PubMed


Diving, hyperbaric oxygen, and decompression have been described as inducers of alterations in various components of the human immune system, such as the distribution of circulating lymphocytes. Hypothetically, the monitoring of specific lymphocyte subsets during hyperbaric exposure, including T- and NK-cell subsets, can serve as biomarkers of hyperbaric stress.
Eight experienced saturation divers and eight reference subjects, naive to deep saturation diving, were examined. Peripheral blood mononuclear cells were isolated before and at different points during a 19.3-d dry heliox saturation dive to 2.64 MPa (254 msw). The NK cell cytotoxicity was estimated in a 4-h 51Cr-release assay using the NK cell sensitive tumor cell-line K562 as target cells. The major lymphocyte subpopulations, with special emphasis on the NK cell subsets, were phenotypically delineated by the use of 4-color flow cytometry.
Although NK cell cytotoxicity increased significantly in the divers during the compression phase and the reference subjects who remained in normoxic conditions outside the chamber, the NK cell cytotoxicity was significantly higher in the divers.
This finding, together with augmentation in the absolute number of circulating NK cells in the divers due to a possible activation of specific parts of the innate cellular immune system during hyperbaric exposure, suggests the monitoring of specific immune functions can be useful as biomarkers of hyperbaric-induced inflammatory stress.

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Available from: Jan Krog, Aug 06, 2015
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    • "For instance, during diving the physical stress (underwater pressure) increases with the water depth (11 atm at 100 m, and 48.6 atm at 480 m, for example; Brubakk et al., 2014). This creates inflammation signaling (Matsuo et al., 2000; Krog et al., 2010), oxidative stress load (Ikeda et al., 2004), extreme tiring experience of body, stress hormone secretion (Hirayanagi et al., 2003), sleep disruption (Nagashima et al., 2002), and the psychological stress in mind (Curley et al., 1979; Biersner et al., 1984), resulting in alterations of divers' mood, cognition and performance efficacy, which are critical for diving work. Previous studies reported different results on relevance between deep water diving (more than 300 m) and mental abilities, potentially due to the limited availability of subjects. "
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