No effect of fitness on brachial or forearm vascular function during acute inflammation in young adults.

Abstract

INTRODUCTION\nAcute inflammation is associated with increased risk of cardiovascular events and impaired vasodilatory capacity. Vasodilatory capacity can be measured in different segments of the arterial tree, however, it is unknown if the effects of acute inflammation are vascular segment specific or if inflammation-induced dysfunction can be attenuated by factors that modulate cardiovascular risk, such as high cardiorespiratory fitness. The purpose of this study was to determine the effect of acute inflammation and fitness on conduit artery, resistance artery, and microvascular function in healthy, young adults.\n\n\nMETHODS\nEleven low fit (5 male, 24 yrs, 34.5±2.9 ml/kg/min) and 12 high fit (7 male, 27 yrs, 56.4±9.7 ml/kg/min) young adults had vascular function assessed at baseline and 24h after a typhoid vaccination. Vascular assessments included flow-mediated dilation (FMD) of the brachial artery, forearm reactive hyperemia (RH) via venous occlusion plethysmography, and near-infrared spectroscopy (NIRS) during a 5-min arterial occlusion.\n\n\nRESULTS\nAcute inflammation was evident with increases in IL-6 and CRP (p<0.01) and mean arterial pressure did not change (p=0.33). FMD was lower in the high fit group, yet both groups reduced FMD at 24h even after controlling for shear (p<0.05). No effect of acute inflammation was observed for RH or NIRS (p>0.05).\n\n\nCONCLUSION\nAcute inflammation had non-uniform effects on vascular function throughout the arterial tree in young adults and fitness did not alter the vascular response. This suggests cardiorespiratory fitness may not protect the vasculature during acute inflammation in young adults in the absence of age- or disease-related decline in vascular function.