Universidad Peruana Cayetano Heredia

Global Reach 2018: reduced flow-mediated dilation stimulated by sustained increases in shear stress in high-altitude excessive erythrocytosis.

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dc.contributor.author Tremblay, Joshua C.
dc.contributor.author Coombs, Geoff B.
dc.contributor.author Howe, Connor A.
dc.contributor.author Vizcardo-Galindo, Gustavo A.
dc.contributor.author Figueroa-Mujica, Romulo J.
dc.contributor.author Bermudez, Daniela
dc.contributor.author Tymko, Michael M.
dc.contributor.author Villafuerte, Francisco C.
dc.contributor.author Ainslie, Philip N.
dc.contributor.author Pyke, Kyra E.
dc.date.accessioned 2019-12-06T21:04:46Z
dc.date.available 2019-12-06T21:04:46Z
dc.date.issued 2019
dc.identifier.uri https://hdl.handle.net/20.500.12866/7608
dc.description.abstract Excessive erythrocytosis [EE; hemoglobin concentration (Hb) >/= 21 g/dL in adult men] is a maladaptive high-altitude pathology associated with increased cardiovascular risk and reduced reactive hyperemia flow-mediated dilation (FMD); however, whether a similar impairment occurs in response to more commonly encountered sustained increases in shear stress [sustained stimulus (SS)-FMD] over a range of overlapping stimuli is unknown. We characterized SS-FMD in response to handgrip exercise in Andeans with and without EE in Cerro de Pasco, Peru (4,330 m). Andean highlanders with EE (n = 17, Hb = 23.2 +/- 1.2 g/dL) and without EE (n = 23, Hb = 18.7 +/- 1.9 g/dL) performed 3 min of rhythmic handgrip exercise at 20, 35, and 50% of maximum voluntary contraction (MVC). Duplex ultrasound was used to continuously record blood velocity and diameter in the brachial artery, and blood viscosity was measured to accurately calculate shear stress. Although baseline shear stress did not differ, Andeans with EE had 22% lower shear stress than Andeans without at 50% MVC (P = 0.004). At 35 and 50% MVC, SS-FMD was 2.1 +/- 2.0 and 2.8 +/- 2.7% in Andeans with EE compared with 4.1 +/- 3.4 and 7.5 +/- 4.5% in those without (P = 0.048 and P < 0.001). The stimulus-response slope (shear stress vs. diameter) was lower in Andeans with EE compared with Andeans without (P = 0.028). This slope was inversely related to Hb in Andeans with EE (r(2) = 0.396, P = 0.007). A reduced SS-FMD in response to small muscle mass exercise in Andeans with EE indicates a generalized reduction in endothelial sensitivity to shear stress, which may contribute to increased cardiovascular risk in this population.NEW & NOTEWORTHY High-altitude excessive erythrocytosis (EE; hemoglobin concentration >/= 21 g/dL) is a maladaptation to chronic hypoxia exposure and is associated with increased cardiovascular risk. We examined flow-mediated dilation (FMD) in response to sustained elevations in shear stress achieved using progressive handgrip exercise [sustained stimulus (SS)-FMD] in Andean highlanders with and without EE at 4,330 m. Andeans with EE demonstrated lower SS-FMD compared with those without. Heightened hemoglobin concentration was related to lower SS-FMD in Andeans with EE. en_US
dc.language.iso eng
dc.publisher American Physiological Society
dc.relation.ispartofseries American Journal of Physiology - Heart and Circulatory Physiology
dc.rights info:eu-repo/semantics/restrictedAccess
dc.rights.uri https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es
dc.subject chronic mountain sickness en_US
dc.subject endothelial function en_US
dc.subject hypoxia en_US
dc.subject progressive handgrip exercise en_US
dc.subject SS-FMD en_US
dc.subject vascular function en_US
dc.title Global Reach 2018: reduced flow-mediated dilation stimulated by sustained increases in shear stress in high-altitude excessive erythrocytosis. en_US
dc.type info:eu-repo/semantics/article
dc.identifier.doi https://doi.org/10.1152/ajpheart.00316.2019
dc.subject.ocde https://purl.org/pe-repo/ocde/ford#3.01.08
dc.subject.ocde https://purl.org/pe-repo/ocde/ford#3.02.04
dc.relation.issn 1522-1539


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