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This Article Full Text Full Text (PDF) All Versions of this Article: 293/5/H3159    most recent 00591.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Demiot, C. Articles by Custaud, M.-A. Search for Related Content PubMed PubMed Citation Articles by Demiot, C. Articles by Custaud, M.-A.

WISE 2005: chronic bed rest impairs microcirculatory endothelium in women

¹CHU d'Angers, Centre de Recherche Clinique, Angers, France; ²Faculté de Pharmacie, Physiopathologie de l'Endothélium INSERM 608, Marseille, France; ³Université d'Angers, Faculté de médecine d'Angers, UMR CNRS 6214, INSERM 771, Angers, France; ⁴Laboratoire de Physiologie de l'Environnement, Faculté de médecine Grange Blanche, Lyon, France; ⁵Institute for Biomedical Problems, Khoroshevskoe shosse 76 A, Moscow, Russia; ⁶CNES, Place Maurice Quentin, Paris, France; and ⁷Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada

Submitted 20 May 2007 ; accepted in final form 30 August 2007

Sedentary behavior has deleterious effects on the cardiovascular system, including reduced endothelial functions. A 2-mo bed rest study in healthy women [women international space simulation for exploration (WISE) 2005 program] presented a unique opportunity to analyze the specific effects of prolonged inactivity without other vascular risk factors on the endothelium. We investigated endothelial properties before and after 56 days of bed rest in 8 subjects who performed no exercise (control group: No-EX) and in 8 subjects who regularly performed treadmill exercise in a lower body negative pressure chamber as well as resistance exercise (countermeasure group, EX). A functional evaluation of the microcirculation in the skin was assessed with laser Doppler. We studied endothelium-dependent and -independent vasodilation using iontophoresis of acetylcholine and sodium nitroprusside, respectively. We also measured circulating endothelial cells (CECs), an index of endothelial damage. In the No-EX group, endothelium-dependent vasodilation was significantly reduced (35.4 ± 4.8% vs. 24.1 ± 3.8%, P < 0.05) by bed rest with a significant increase in the number of CECs (3.6 ± 1.4 vs. 10.6 ± 2.7 ml^–1, P < 0.05). In the EX group, endothelium-dependent vasodilation and number of CECs were preserved. Our study shows that in humans prolonged bed rest causes impairment of endothelium-dependent function at the microcirculatory level, along with an increase in circulating endothelial cells. Microcirculatory endothelial dysfunction might participate in cardiovascular deconditioning, as well as in several bed rest-induced pathologies. We therefore conclude that the endothelium should be a target for countermeasures during periods of prolonged deconditioning.

bed rest studies; cardiovascular deconditioning; iontophoresis; circulating endothelial cells