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Oral glucose challenge impairs skeletal muscle microvascular blood flow in healthy people

journal contribution
posted on 2023-05-19, 20:40 authored by Russell, RD, Hu, D, Timothy GreenawayTimothy Greenaway, James SharmanJames Sharman, Stephen RattiganStephen Rattigan, Stephen RichardsStephen Richards, Michelle Keske
Skeletal muscle microvascular (capillary) blood flow increases in the postprandial state or during insulin infusion due to dilation of precapillary arterioles to augment glucose disposal. This effect occurs independently of changes in large artery function. However, acute hyperglycemia impairs vascular function, causes insulin to vasoconstrict precapillary arterioles, and causes muscle insulin resistance in vivo. We hypothesized that acute hyperglycemia impairs postprandial muscle microvascular perfusion, without disrupting normal large artery hemodynamics, in healthy humans. Fifteen healthy people (5 F/10 M) underwent an oral glucose challenge (OGC, 50 g glucose) and a mixed-meal challenge (MMC) on two separate occasions (randomized, crossover design). At 1 h, both challenges produced a comparable increase (6-fold) in plasma insulin levels. However, the OGC produced a 1.5-fold higher increase in blood glucose compared with the MMC 1 h postingestion. Forearm muscle microvascular blood volume and flow (contrast-enhanced ultrasound) were increased during the MMC (1.3- and 1.9-fold from baseline, respectively, P < 0.05 for both) but decreased during the OGC (0.7- and 0.6-fold from baseline, respectively, P < 0.05 for both) despite a similar hyperinsulinemia. Both challenges stimulated brachial artery flow (ultrasound) and heart rate to a similar extent, as well as yielding comparable decreases in diastolic blood pressure and total vascular resistance. Systolic blood pressure and aortic stiffness remained unaltered by either challenge. Independently of large artery hemodynamics, hyperglycemia impairs muscle microvascular blood flow, potentially limiting glucose disposal into skeletal muscle. The OGC reduced microvascular blood flow in muscle peripherally and therefore may underestimate the importance of skeletal muscle in postprandial glucose disposal.

History

Publication title

American Journal of Physiology - Endocrinology and Metabolism

Volume

315

Pagination

E307-E315

ISSN

0193-1849

Department/School

Menzies Institute for Medical Research

Publisher

Amer Physiological Soc

Place of publication

9650 Rockville Pike, Bethesda, USA, Md, 20814

Rights statement

Copyright © 2018 the American Physiological Society

Repository Status

  • Restricted

Socio-economic Objectives

Clinical health not elsewhere classified

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