Determinants of short-term variation in arterial flow-mediated dilatation in healthy young men

2006 ◽  
Vol 110 (4) ◽  
pp. 475-482 ◽  
Author(s):  
Mikko J. Järvisalo ◽  
Laura Jartti ◽  
Jukka Marniemi ◽  
Tapani Rönnemaa ◽  
Jorma S. A. Viikari ◽  
...  
Keyword(s):  
Endothelial Function ◽  
Brachial Artery ◽  
Serum Insulin ◽  
Circadian Variation ◽  
Low Fat ◽  
Ultrasound Technique ◽  
Brachial Artery Diameter ◽  
Flow Mediated Dilatation ◽  
Hourly Variation ◽  
Fat Meal

Brachial artery FMD (flow-mediated dilatation) is widely used as a marker of systemic arterial endothelial function. FMD, however, shows considerable 25% day-to-day variation that hinders its clinical use. The reasons for this variability are poorly characterized. Therefore the present study was designed to clarify factors responsible for the hourly variation in endothelial function, including consuming a low-fat meal and circadian rhythms in endogenous hormonal levels. Brachial artery FMD, along with serum glucose, triacylglycerols (triglycerides) and levels of several hormones were measured six times per day on two separate days 1 week apart. On one day, the subjects (healthy males: n=12, mean age, 24 years) ate a light breakfast and a standardized lunch (23.5% fat, 48.7% carbohydrate and 27.8% protein). On the other day, they had a similar breakfast after which they fasted. Postprandial FMD values (both after breakfast and after lunch) were similar to baseline FMD. FMD showed a 28% hourly variation and 27% weekly variation. Variation in plasma levels of insulin (P=0.02) associated negatively and DHPG (3,4-dihydroxyphenylglycol) (P=0.001), a marker of sympathetic nervous activation, associated positively with variation in FMD. The effects of DHPG and insulin on FMD were independent of changes in baseline brachial artery diameter, although DHPG was also inversely associated with baseline diameter. Eating a regular low-fat meal does not have any measurable effects on brachial artery endothelial function. These data suggest that strict requirements for fasting conditions may be unnecessary when measuring peripheral endothelial function using the ultrasound technique. Circadian variation in serum insulin and sympathetic tone are physiological determinants of endothelial function.

A comparison between active- and reactive-hyperaemia-induced brachial artery vasodilation

2006 ◽  
Vol 110 (3) ◽  
pp. 387-392 ◽  
Author(s):  
Jaume Padilla ◽  
Ryan A. Harris ◽  
Alyce D. Fly ◽  
Lawrence D. Rink ◽  
Janet P. Wallace
Keyword(s):  
Endothelial Function ◽  
Brachial Artery ◽  
Repeated Measures ◽  
Reactive Hyperaemia ◽  
High Fat ◽  
Low Fat ◽  
Balanced Design ◽  
Treatment Conditions ◽  
Main Effects ◽  
Fat Meal

The measurement of brachial artery vasodilation in response to a hyperaemic stimulus has been used extensively to assess changes in endothelial function. However, whether or not similar changes occur in response to an active hyperaemic stimulus is unknown. The purpose of the present study was to compare brachial artery vasodilation in response to an active compared with a reactive hyperaemic stimulus following a known perturbation of endothelial function. Eight apparently healthy adults were assigned to four treatment conditions in a counter-balanced design: (i) low-fat meal with active hyperaemic stimulus (LFM-A), (ii) high-fat meal with active hyperaemic stimulus (HFM-A), (iii) low-fat meal with reactive hyperaemic stimulus (LFM-R), and (iv) high-fat meal with reactive hyperaemic stimulus (HFM-R). Meals were ingested at 08:00 hours on each treatment day. Brachial artery vasodilation was assessed via ultrasound 4 h after ingestion of each meal. The active hyperaemic stimulus was induced by 5 min of rhythmic handgrip exercise, whereas reactive hyperaemia was induced by 5 min of forearm occlusion. Brachial artery vasodilation was expressed as the percentage change in diameter from baseline to post-active/reactive hyperaemia. Using a 2×2 repeated measures ANOVA, a significant stimulus×meal interaction (P=0.025) was found. Simple main effects revealed no difference (P=0.541) in brachial artery vasodilation between LFM-A (5.75±1.64%) and HFM-A (6.39±1.45%); however, a significant decrease (P=0.014) in brachial artery vasodilation was found in the HFM-R (4.29±1.64%) compared with the LFM-R (7.18±1.13%) treatment. In conclusion, the measurement of brachial artery vasodilation in response to active hyperaemia did not detect a change in endothelial function following a single perturbation meal, whereas reactive hyperaemia did.

Flow-mediated dilatation following wrist and upper arm occlusion in humans: the contribution of nitric oxide

2001 ◽  
Vol 101 (6) ◽  
pp. 629-635 ◽  
Author(s):  
Sagar N. DOSHI ◽  
Katerina K. NAKA ◽  
Nicola PAYNE ◽  
Christopher J.H. JONES ◽  
Moira ASHTON ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Function ◽  
Brachial Artery ◽  
Peak Flow ◽  
Ultrasound Probe ◽  
Upper Arm ◽  
Flow Mediated Dilatation ◽  
Synthase Inhibitor ◽  
Increased Blood Flow ◽  
Similar Peak

Flow-mediated dilatation (FMD) of the brachial artery assessed by high-resolution ultrasound is widely used to measure endothelial function. However, the technique is not standardized, with different groups using occlusion of either the wrist or the upper arm to induce increased blood flow. The validity of the test as a marker of endothelial function rests on the assumption that the dilatation observed is endothelium-dependent and mediated by nitric oxide (NO). We sought to compare the NO component of brachial artery dilatation observed following wrist or upper arm occlusion. Dilatation was assessed before and during intra-arterial infusion of the NO synthase inhibitor NG-monomethyl-l-arginine (l-NMMA) following occlusion of (i) the wrist (distal to ultrasound probe) and (ii) the upper arm (proximal to ultrasound probe) for 5min in ten healthy males. Dilatation was significantly greater after upper arm occlusion (upper arm, 11.62±3.17%; wrist, 7.25±2.49%; P = 0.003). During l-NMMA infusion, dilatation after wrist occlusion was abolished (from 7.25±2.49% to 0.16±2.24%; P < 0.001), whereas dilatation after upper arm occlusion was only partially attenuated (from 11.62±3.17% to 7.51±2.34%; P = 0.006). The peak flow stimulus was similar after wrist and upper arm occlusion. We conclude that dilatation following upper arm occlusion is greater than that observed after wrist occlusion, despite a similar peak flow stimulus. l-NMMA infusion revealed that FMD following wrist occlusion is mediated exclusively by NO, while dilatation following upper arm occlusion comprises a substantial component not mediated by NO, most probably related to tissue ischaemia around the brachial artery. FMD following wrist occlusion may be a more valid marker of endothelial function than dilatation following upper arm occlusion.

Effects of polycythemia on systemic endothelial function in chronic hypoxic lung disease

2011 ◽  
Vol 110 (5) ◽  
pp. 1196-1203 ◽  
Author(s):  
Laurent Boyer ◽  
Vicky Chaar ◽  
Gabriel Pelle ◽  
Bernard Maitre ◽  
Christos Chouaid ◽  
...  
Keyword(s):  
Endothelial Function ◽  
Brachial Artery ◽  
Blood Viscosity ◽  
Vascular Function ◽  
Venous Occlusion ◽  
Chronic Obstructive ◽  
Brachial Artery Diameter ◽  
Obstructive Pulmonary Disease ◽  
Vasoconstrictor Response ◽  
No Release

Chronic obstructive pulmonary disease (COPD) is a major risk factor for cardiovascular disease. Polycythemia, a common complication of hypoxic COPD, may affect systemic vascular function by altering blood viscosity, vessel wall shear stress (WSS), and endothelium-derived nitric oxide (NO) release. Here, we evaluated the effects of hypoxia-related polycythemia on systemic endothelial function in patients with COPD. We investigated blood viscosity, WSS, and endothelial function in 15 polycythemic and 13 normocythemic patients with COPD of equal severity, by recording brachial artery diameter variations in response to hyperemia and by using venous occlusion plethysmography (VOP) to measure forearm blood flow (FBF) responses to a brachial artery infusion of acetylcholine (ACh), bradykinin (BK), sodium nitroprusside (SNP), substance P (SP), isoptin, and N-monomethyl-l-arginine (l-NMMA). At baseline, polycythemic patients had higher blood viscosity and larger brachial artery diameter than normocythemic patients but similar calculated WSS. Flow-mediated brachial artery vasodilation was increased in the polycythemic patients, in proportion to the hemoglobin levels. ACh-induced vasodilation was markedly impaired in the polycythemic patients and negatively correlated with hemoglobin levels. FBF responses to endothelium- (BK, SP) and non-endothelium-dependent (SNP, isoptin) vasodilators were not significantly different between the two groups. l-NMMA infusion induced a similar vasoconstrictor response in both groups, in accordance with their similar baseline WSS. In conclusion, systemic arteries in polycythemic patients adjust appropriately to chronic or acute WSS elevations by appropriate basal and stimulated NO release. Overall, our results suggest that moderate polycythemia has no adverse effect on vascular function in COPD.

scholarly journals Noninvasive Assessment of Endothelium-Dependent Flow-Mediated Dilation of the Brachial Artery

1997 ◽  
Vol 2 (2) ◽  
pp. 87-92 ◽  
Author(s):  
Akimi Uehata ◽  
Eric H Lieberman ◽  
Marie D Gerhard ◽  
Todd J Anderson ◽  
Peter Ganz ◽  
...  
Keyword(s):  
Blood Flow ◽  
Endothelial Function ◽  
Brachial Artery ◽  
Vascular Function ◽  
Reactive Hyperemia ◽  
Intraobserver Variability ◽  
Flow Mediated Dilation ◽  
Noninvasive Technique ◽  
Brachial Artery Diameter ◽  
Cuff Occlusion

Coronary atherosclerosis is characterized by an early loss of endothelium-dependent vasodilation. However, the methods of assessing coronary endothelial function are invasive and difficult to repeat over time. Recently, a noninvasive ultrasound method has been widely used to measure flow-mediated dilation in the brachial artery as a surrogate test for endothelial function. We seek to further validate this method of measuring vascular function. The brachial artery diameters and blood flow of 20 normal volunteers (10 males and 10 females) were measured using high resolution (7.5 MHz) ultrasound and strain gauge plethysmography. Flow-mediated endothelium-dependent vasodilation was measured in the brachial artery during reactive hyperemia after 5 minutes of cuff occlusion in the upper arm. The brachial artery diameter increased maximally by 9.7 ± 4.3% from baseline at 1 min after cuff release and blood flow increased by 1002 ± 376%. Five min of cuff occlusion was sufficient to achieve 97 ± 6% of maximal brachial artery dilation and degree of dilation was not different whether the cuff was inflated proximally or distally to the image site. The intraobserver variability in measuring brachial diameters was 2.9 % and the variability of the hyperemic response was 1.4%. In young, healthy men and women, the baseline brachial artery diameter was the only factor that was predictive of the flow-mediated vasodilation response. The brachial noninvasive technique has been further validated by the determination of flow-mediated dilation. This method of assessing endothelial function may help to determine the importance of vasodilator dysfunction as a risk factor in the development of atherosclerosis.

Deletion polymorphism in the α2B-adrenergic receptor gene is associated with flow-mediated dilatation of the brachial artery

2002 ◽  
Vol 103 (5) ◽  
pp. 517-524 ◽  
Author(s):  
Paula HEINONEN ◽  
Laura JARTTI ◽  
Mikko J. JÄRVISALO ◽  
Ullamari PESONEN ◽  
Jaakko A. KAPRIO ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Endothelial Function ◽  
Brachial Artery ◽  
Adrenergic Receptor ◽  
Intima Media Thickness ◽  
Deletion Variant ◽  
Media Thickness ◽  
Increased Risk ◽  
Flow Mediated Dilatation ◽  
Carotid Artery Compliance

A deletion variant of the α2B-adrenergic receptor (α2B-AR) has been associated with an increased risk of acute cardiac events in middle-aged men. Our aim was to determine the possible associations between the α2B-AR gene deletion variant and indicators of subclinical atherosclerosis in the brachial and carotid arteries. A total of 148 middle-aged men participating in an epidemiological twin study on risk factors for subclinical coronary heart disease were genotyped using PCR. Flow-mediated dilatation (FMD) of the brachial artery, carotid artery compliance and carotid intima-media thickness were measured using high-resolution ultrasound. FMD was 6.2±5.0% in subjects with the I/I (insertion/insertion) genotype, 5.5±4.1% in the I/D (insertion/deletion) group and 4.1±3.8% in the D/D (deletion/deletion) group (P = 0.03 for trend). In multivariate regression analysis controlling for age, presence of hypertension, smoking, use of angiotensin-converting enzyme inhibitors and plasma levels of low-density lipoprotein cholesterol and lipoprotein (a), the association between the α2B-AR genotype and FMD remained significant (P = 0.04 for trend). The α2B-AR genotype was not associated with intima-media thickness or carotid artery compliance. These findings indicate that subjects homozygous for the deletion allele of α2B-AR appear to have an increased risk of impaired endothelial function, which may provide an explanation for the previously observed increased risk of myocardial infarction in male subjects with this genotype. It is not known whether the association of the α2B-AR polymorphism with endothelial function is direct, or is mediated via altered sympathetic activation.

The effect of acute fish-oil supplementation on endothelial function and arterial stiffness following a high-fat meal

2010 ◽  
Vol 35 (3) ◽  
pp. 294-302 ◽  
Author(s):  
Christopher A. Fahs ◽  
Huimin Yan ◽  
Sushant Ranadive ◽  
Lindy M. Rossow ◽  
Stamatis Agiovlasitis ◽  
...  
Keyword(s):  
Arterial Stiffness ◽  
Endothelial Function ◽  
Fish Oil ◽  
Brachial Artery ◽  
Omega 3 ◽  
High Fat ◽  
Time Interaction ◽  
Artery Stiffness ◽  
Fish Oil Supplementation ◽  
Fat Meal

This study examined whether a commercially available fish-oil supplement offers protection from the acute effects of a high-fat meal (HFM) on endothelial function and arterial stiffness. An HFM causes acute impairments in endothelial function, whereas the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have a variety of cardioprotective effects. However, little is known about the efficacy of moderate fish-oil supplementation on the endothelial dysfunction induced by an HFM. Endothelial function (brachial artery flow-mediated dilation (FMD)), forearm blood flow (FBF), total hyperemia, central and peripheral blood pressure, and central artery stiffness were assessed in 20 healthy men (n = 10) and women (n = 10) at rest and 4 h after an HFM supplemented with either placebo or ∼1 g EPA and DHA. Brachial artery FMD normalized for shear rate was significantly impaired (p = 0.033) following the HFM with placebo but remained unchanged compared with baseline following the HFM with the fish-oil supplement (p = 0.039; condition × time interaction). Resting FBF (p = 0.020) and total hyperemia (p = 0.014) were elevated following the HFM. All other vascular and hemodynamic measurements were unchanged in both trials. Commercially available fish-oil supplements taken with an HFM appear to preserve endothelial function following an HFM.

scholarly journals Association of the polymorphism in the androgen receptor gene and endothelial function in men with type 2 diabetes

2015 ◽  
Vol 18 (4) ◽  
pp. 35-40 ◽  
Author(s):  
Irina Alekseevna Khripun ◽  
Sergey Vladislavovich Vorobyev ◽  
Michael Iosifovich Kogan
Keyword(s):  
Type 2 Diabetes ◽  
Lipid Metabolism ◽  
Androgen Receptor ◽  
Endothelial Function ◽  
Flow Velocity ◽  
Brachial Artery ◽  
Cag Repeats ◽  
Atherogenic Index ◽  
Brachial Artery Diameter

In recent years, actively studied the effect of androgen deficiency on the cardiovascular system, including endothelial function. Genomic effects of testosterone caused by the length of CAG repeats polymorphism in the androgen receptor (AR) gene.Aim. To examine the association of the polymorphism in the AR gene and carbohydrate, lipid metabolism, endothelial function in men with type 2 diabetes.Materials and methods. We examined 88 men, aged 40-65 years (mean age 53±6,4years) with type 2 diabetes. All patients underwent the study of carbohydrate and lipid metabolism, the assessment of vasomotor endothelial function of the brachial artery by ultrasound sonography, were studied biochemical markers of endothelial dysfunction – ICAM-1, VCAM-1, p-selectin, e-selectin, resistin and number of CAG-repeats in the AR gene. Statistical analysis was performed using the application package SPSS 21,0 using regression analysis.Results. The number of CAG repeats had a significant positive regression to the level of total testosterone, a weak negative regression of the number of CAG repeats in the AR gene and lipid metabolism: triglycerides, LDL, atherogenic index. The assessment of the brachial artery ultrasonography revealed negative regression of the baseline brachial artery diameter and blood flow velocity in the endothelium-dependent vasodilation. The number of CAG repeats was significantly correlated with the levels of p-selectin and resistin. Thus, increasing the number of CAG repeats in the AR gene via a weakening of sensitivity to androgens leads to disruption of endothelial function in men with type 2 diabetes. Increasing the number of CAG repeats in the AR gene leads to deterioration of linear flow velocity during the test with reactive hyperemia with increasing production of p-selectin and resistin.Conclusions. The number of CAG repeats in the AR gene can be regarded as a predictor of the development and progression of cardiovascular lesions in men with type 2 diabetes.

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