Enforced physical inactivity increases endothelial microparticle levels in healthy volunteers

• Published in: American journal of physiology. Heart and circulatory physiology Vol. 299; no. 2; pp. H248 - H256
• Main Authors: Navasiolava, Nastassia M., Dignat-George, Françoise, Sabatier, Florence, Larina, Irina M., Demiot, Claire, Fortrat, Jacques-Olivier, Gauquelin-Koch, Guillemette, Kozlovskaya, Inesa B., Custaud, Marc-Antoine
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.08.2010
• Subjects: Acetylcholine; Acetylcholine - administration & dosage; Administration, Cutaneous; Biochemistry, Molecular Biology; Biological Markers; Biomarkers - blood; Blood Glucose; Blood Glucose - metabolism; Cardiovascular system; Cell-Derived Microparticles; Cell-Derived Microparticles - pathology; Cells; Circulatory system; E-Selectin; E-Selectin - blood; Endothelial Cells; Endothelial Cells - drug effects; Endothelial Cells - metabolism; Endothelial Cells - pathology; Endothelium, Vascular; Endothelium, Vascular - drug effects; Endothelium, Vascular - metabolism; Endothelium, Vascular - pathology; Endothelium, Vascular - physiopathology; Exercise; Genetics; Genomics; Human genetics; Human health and pathology; Humans; Iontophoresis; Laser-Doppler Flowmetry; Leg; Life Sciences; Lipids; Lipids - blood; Male; Microcirculation; Molecular biology; Neurobiology; Neurons and Cognition; Nitroprusside; Nitroprusside - administration & dosage; Physiology; Plasma; Sedentary Lifestyle; Skin; Skin - blood supply; Time Factors; Tissues; Tissues and Organs; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor A - blood; Vascular Endothelial Growth Factor Receptor-1; Vascular Endothelial Growth Factor Receptor-1 - blood; Vasodilation; Vasodilator Agents; Vasodilator Agents - administration & dosage; Weightlessness Simulation; Young Adult
• ISSN: 0363-6135; 1522-1539; 1522-1539
• DOI: 10.1152/ajpheart.00152.2010

A sedentary lifestyle has adverse effects on the cardiovascular system, including impaired endothelial functions. Subjecting healthy men to 7 days of dry immersion (DI) presented a unique opportunity to analyze the specific effects of enhanced inactivity on the endothelium. We investigated endothelial properties before, during, and after 7 days of DI involving eight subjects. Microcirculatory functions were assessed with laser Doppler in the skin of the calf. We studied basal blood flow and endothelium-dependent and -independent vasodilation. We also measured plasma levels of microparticles, a sign of cellular dysfunction, and soluble endothelial factors, reflecting the endothelial state. Basal flow and endothelium-dependent vasodilation were reduced by DI (22 ± 4 vs. 15 ± 2 arbitrary units and 29 ± 6% vs. 12 ± 6%, respectively, P < 0.05), and this was accompanied by an increase in circulating endothelial microparticles (EMPs), which was significant on day 3 (42 ± 8 vs. 65 ± 10 EMPs/μl, P < 0.05), whereas microparticles from other cell origins remained unchanged. Plasma soluble VEGF decreased significantly during DI, whereas VEGF receptor 1 and soluble CD62E were unchanged, indicating that the increase in EMPs was associated with a change in antiapoptotic tone rather than endothelial activation. Our study showed that extreme physical inactivity in humans induced by 7 days of DI causes microvascular impairment with a disturbance of endothelial functions, associated with a selective increase in EMPs. Microcirculatory endothelial dysfunction might contribute to cardiovascular deconditioning as well as to hypodynamia-associated pathologies. In conclusion, the endothelium should be the focus of special care in situations of acute limitation of physical activity.