High-glucose mixed-nutrient meal ingestion impairs skeletal muscle microvascular blood flow in healthy young men

Abstract

Oral glucose ingestion leads to impaired muscle microvascular blood flow (MBF), which may contribute to acute hyperglycemia-induced insulin resistance. We investigated whether incorporating lipids and protein into a high-glucose load would prevent postprandial MBF dysfunction. Ten healthy young men (age, 27 yr [24, 30], mean with lower and upper bounds of the 95% confidence interval; height, 180 cm [174, 185]; weight, 77 kg [70, 84]) ingested a high-glucose (1.1 g/kg glucose) mixed-nutrient meal (10 kcal/kg; 45% carbohydrate, 20% protein, and 35% fat) in the morning after an overnight fast. Femoral arterial blood flow was measured via Doppler ultrasound, and thigh MBF was measured via contrast-enhanced ultrasound, before meal ingestion and 1 h and 2 h postprandially. Blood glucose and plasma insulin were measured at baseline and every 15 min throughout the 2-h postprandial period. Compared with baseline, thigh muscle microvascular blood volume, velocity, and flow were significantly impaired at 60 min postprandial (−25%, −27%, and −46%, respectively; all P < 0.05) and to a greater extent at 120 min postprandial (−37%, −46%, and −64%; all P < 0.01). Heart rate and femoral arterial diameter, blood velocity, and blood flow were significantly increased at 60 min and 120 min postprandial (all P < 0.05). Higher blood glucose area under the curve was correlated with greater MBF dysfunction ( R2 = 0.742; P < 0.001). Ingestion of a high-glucose mixed-nutrient meal impairs MBF in healthy individuals for up to 2 h postprandial.

Prior exercise enhances skeletal muscle microvascular blood flow and mitigates microvascular flow impairments induced by a high‐glucose mixed meal in healthy young men

“…For example, the ingestion of a low-glucose mixed-nutrient meal (41 g carbohydrate, 25.1 g as glucose) in healthy adults increases microvascular blood flow, whereas an oral glucose challenge (50 g of glucose) matched for postprandial plasma insulin levels impairs postprandial muscle microvascular blood flow (Russell et al 2018). Furthermore, our team also reported in healthy males that the ingestion of protein (∼39 g) and lipids (∼30 g) alongside a high-glucose load (1.1 g/kg bodyweight of glucose) leads to a similar decrease in muscle microvascular blood flow which persists for up to 2 h postprandially (Parker et al 2020). In both studies greater glycaemic excursions were correlated with a greater decrease in muscle microvascular blood flow (Russell et al 2018;Parker et al 2020), supporting the notion that acute hyperglycaemia can transiently impair muscle microvascular perfusion in healthy adults.…”

“…Compared to lean humans, muscle microvascular blood flow is impaired in obese adults following a euglycaemic-hyperinsulinaemic clamp or ingestion of a mixed-nutrient meal (Clerk et al 2006;Keske et al 2009), reflecting similar reports from rodent models of insulin resistance (Wallis et al 2002;Clerk et al 2007;St-Pierre et al 2010). Even in healthy individuals acute hyperglycaemia impairs muscle microvascular blood flow (Russell et al 2018;Parker et al 2020). For example, the ingestion of a low-glucose mixed-nutrient meal (41 g carbohydrate, 25.1 g as glucose) in healthy adults increases microvascular blood flow, whereas an oral glucose challenge (50 g of glucose) matched for postprandial plasma insulin levels impairs postprandial muscle microvascular blood flow (Russell et al 2018).…”

“…Participants completed a 24 h diet diary on the day prior to their first trial, which they then replicated for their subsequent testing conditions. Macro-and microvascular blood flow responses to the meal at rest (control trial; n = 10) have been previously published (Parker et al 2020). Data from the eight participants who completed all J Physiol 599.1 Height (cm) 180.1 ± 7.7 180.0 (175.8, 184.0) Weight kg79.5 ± 9.1 79.3 (70.8, 87.5) Body mass index (kg/m 2 ) 24.5 ± 1.5 24.3 (23.6, 25.5) Self-reported weekly physical activity level (IPAQ)…”

“…Digital images were analysed using Qlab software (QLAB, Philips Healthcare, Andover, MA, USA). The raw acoustic intensity was background subtracted (0.5 s frame) to eliminate signal from larger vessels and tissue artefacts, as previously done (Russell et al 2018;Parker et al 2020). The background subtracted acoustic intensity acquired from the vastus lateralis region of interest was then plotted over time and curve fitted using the equation y = A(1 − e −β(t−tb) ), where y is acoustic intensity, t is time, t b is the background time, A is the plateau of acoustic intensity (a measure of microvascular blood volume), and β is the rate constant (a measure of microvascular capillary refilling rate).…”

“…Minor variations in the contrast agent concentration may occur and be influenced by factors such as total body blood volume and body composition. As such, the microsphere concentration within the superficial femoral artery was measured and used to normalize microvascular blood flow data within and between participants, as previously done (Parker et al 2020). In brief, the acoustic intensity from a region of interest inside the superficial femoral artery was measured and averaged over a 3-s period for all time points.…”