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Five days of head-down-tilt bed rest induces noninflammatory shedding of L-selectin.
- Source :
-
Journal of applied physiology (Bethesda, Md. : 1985) [J Appl Physiol (1985)] 2013 Jul 15; Vol. 115 (2), pp. 235-42. Date of Electronic Publication: 2013 May 16. - Publication Year :
- 2013
-
Abstract
- Head-down-tilt bed rest (HDTBR) is a popular model, simulating alterations of gravitation during space missions. The aim of this study was to obtain a better insight into the complexly orchestrated regulations of HDTBR-induced immunological responses, hypothesizing that artificial gravity can mitigate these HDTBR-related physiological effects. This crossover-designed 5 days of HDTBR study included three protocols with no, or daily 30 min of centrifugation or 6 × 5 min of centrifugation. Twelve healthy, male participants donated blood pre-HDTBR, post-HDTBR, and twice during HDTBR. Cellular immune changes were assessed either by enumerative and immune cell phenotyping assays or by functional testing of responses to either recall antigens or receptor-dependent activation by chemotactic agents N-formyl-methionyl-leucyl-phenylalanine (fMLP) and with TNF-α. The expression of the adhesion molecule L-selectin (CD62L) on the surface of granulocytes and its shedding into plasma samples were measured. In parallel, other humoral factor, such as interleukin-6 and interleukin-8, parameters of endothelial damage (glycocalyx) were determined. Hematocrit and hemoglobin were significantly increased during HDTBR. Although immune functional tests did not indicate a change in the immune performance, the expression of CD62L on resting granulocytes was significantly shed by 50% during HDTBR. Although the latter is normally associated to an activation of inflammatory innate immune responses and during interaction of granulocytes with the endothelium, CD62L shedding was, however, not related either to a systemic inflammatory alteration or to shedding of the endothelial glycocalyx during bed rest. This suggests a noninflammatory or "mechanical" shedding related to fluid shifts during head-down intervention and not to an acute inflammatory process.
- Subjects :
- Adult
Bed Rest methods
Cross-Over Studies
Endothelium immunology
Endothelium metabolism
Endothelium physiology
Glycocalyx immunology
Glycocalyx metabolism
Granulocytes immunology
Granulocytes metabolism
Granulocytes physiology
Homeostasis immunology
Homeostasis physiology
Humans
Immunity, Cellular immunology
Immunity, Innate immunology
Inflammation immunology
Interleukin-6 immunology
Interleukin-6 metabolism
Interleukin-8 immunology
Interleukin-8 metabolism
Male
Tumor Necrosis Factor-alpha immunology
Tumor Necrosis Factor-alpha metabolism
Head-Down Tilt physiology
Inflammation metabolism
Inflammation physiopathology
L-Selectin immunology
L-Selectin metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1522-1601
- Volume :
- 115
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Journal of applied physiology (Bethesda, Md. : 1985)
- Publication Type :
- Academic Journal
- Accession number :
- 23681910
- Full Text :
- https://doi.org/10.1152/japplphysiol.00381.2013