Relationship between changes in brachial artery flow-mediated dilation and basal release of nitric oxide in subjects with Type 2 diabetes

Abstract

Relationship between changes in brachial artery flow-mediated dilation and basal release of nitric oxide in subjects with Type 2 diabetes. Am J Physiol Heart Circ Physiol 291: H1193-H1199, 2006. First published March 24, 2006 doi:10.1152/ajpheart.01176.2005.-Assessment of flow-mediated dilation (FMD) after forearm ischemia is widely used as a noninvasive bioassay of stimulated nitric oxide (NO)-mediated conduit artery vasodilator function in vivo. Whether this stimulated endothelial NO function reflects basal endothelial NO function is unknown. To test this hypothesis, retrospective analysis of randomized crossover studies was undertaken in 17 subjects with Type 2 diabetes; 9 subjects undertook an exercise training or control period, whereas the remaining 8 subjects were administered an angiotensin II receptor blocker or placebo. FMD was assessed by using wall tracking of high-resolution brachial artery ultrasound images in response to reactive hyperemia. Resistance vessel basal endotheliumdependent NO function was assessed by using intrabrachial administration of N G -monomethyl-L-arginine (L-NMMA) and plethysmographic assessment of forearm blood flow (FBF). FMD was higher after intervention compared with control/placebo (6.15 Ϯ 0.53 vs. 3.81 Ϯ 0.72%, P Ͻ 0.001). There were no significant changes in the FBF responses to L-NMMA. Regression analysis between FMD and L-NMMA responses at entry to the study revealed an insignificant correlation (r ϭ Ϫ0.10, P ϭ 0.7), and improvements in FMD with the interventions were not associated with changes in the L-NMMA responses (r ϭ Ϫ0.04, P ϭ 0.9). We conclude that conduit arterystimulated endothelial NO function (FMD) does not reflect basal resistance vessel endothelial NO function in subjects with Type 2 diabetes.exercise; acetylcholine; resistance vessel; conduit artery NITRIC OXIDE (NO) bioavailability is thought to play an important atheroprotective role because it inhibits numerous processes implicated in the progression of atherosclerosis, including LDL oxidation, platelet aggregation, monocyte adhesion, and smooth muscle cell proliferation (4,13,30,35). The vascular endothelium releases NO basally (33) and in combination with other vasodilators (e.g., prostacyclin and endothelium-derived hyperpolarizing factor) in response to increases in flow-associated shear stress (25).Anderson et al. (1) were the first to demonstrate that the latter response in a conduit artery results in dilation that could be observed noninvasively via ultrasound imaging (flow-mediated dilation; FMD), whereas Sinoway et al. (32) also provided early evidence for flow-mediated conduit artery dilation. The FMD approach involves a short period of occlusion of the forearm that evokes forearm resistance vessel dilation (11). On release of occlusion, there is a substantial but transient elevation in brachial artery flow velocity providing an increased shear stress stimulus and resulting in FMD.In the early 1990s, Celermajer et al. (5-8) hypothesized and demonstrated that endothelial vasodilator dysfun...

Vascular responsiveness measured by tissue oxygen saturation reperfusion slope is sensitive to different occlusion durations and training status

“…Vascular reactivity has been commonly measured by FMD, and it has been well established through previous studies that exercise training improves endothelial function (Rakobowchuk et al 2008;Tinken et al 2008;Black et al 2009;Thijssen et al 2011b;Currie et al 2012). Additionally, FMD has been shown to differentiate between clinical populations and healthy control subjects (Maiorana et al 2001a;Modena et al 2002;Walsh et al 2003;Green et al 2006;Currie et al 2012); however, some studies using FMD have failed to find differences in groups that were expected to show them. Using the reperfusion slope, or slope 2 S tO 2 , which has been shown to correlate with FMD responses (McLay et al 2016a), group changes in vascular responsiveness might be easier to detect in the sense that differences can be established across a wide range of stimuli.…”

“…Flow-mediated dilatation (FMD) via Doppler ultrasound is currently the most widely used technique to assess vascular responsiveness non-invasively in humans, and has been well documented to detect differences in vascular responsiveness following interventions in healthy and diseased individuals (Maiorana et al 2001a;Modena et al 2002;Walsh et al 2003;Green et al 2006;Currie et al 2012). Nonetheless, FMD is dependent upon the use of high-cost equipment and skilled personnel required for data acquisition, and limited by a high coefficient of variation upon repeated measures (Hijmering et al 2001;McLay et al 2016a).…”

Flow-Mediated Dilation and Intima-Media Thickness of the Brachial and Axillary Arteries in Individuals With and Without Inducible Axillary Artery Compression

“…In conclusion, the only outcome measure to show a significant deleterious response to inducible axillary artery compression was one that is thought to be largely mediated by NO (Corretti et al 2002;Deanfield et al 2005;Green et al 2006;Joannides et al 1995;Pyke and Tschakovsky 2005). A reduction in NO bioavailability, or sensitivity, affects the balance between vasodilators and vasoconstrictors acting on the endothelial monolayer and, as such, its antiinflammatory, antithrombotic and antiatherogenic properties are diminished.…”

Endothelial function in individuals with coronary artery disease with and without type 2 diabetes mellitus

“…T2DM and CAD are both known to affect endothelial function, and many studies have examined the association between either CAD 26 or T2DM 19,20 and endothelial function by measuring FMD. Neunteufl et.…”