Dilation In Young Adults Research Articles

Acute aerobic exercise enhances cerebrovascular shear-mediated dilation in young adults: the role of cerebral shear.

Exercise-induced increases in shear rate (SR) acutely improve peripheral endothelial function, but the presence of this mechanism in cerebral arteries remains unclear. Thus, we evaluated shear-mediated dilation of the internal carotid artery (ICA), which is an index of cerebrovascular endothelial function, before and after exercise. Shear-mediated dilation was measured with 30 s of hypercapnia in 16 young adults before and 10 min after 30 min of sitting rest (CON) or three cycling exercises on four separate days. The target exercise intensity was 80% of oxygen uptake at the ventilatory threshold. To manipulate the ICA SR during exercise, participants breathed spontaneously (ExSB, SR increase) or hyperventilated without (ExHV, no increase in SR) or with ([Formula: see text], restoration of SR increase) addition of CO2 to inspiratory air. Shear-mediated dilation was calculated as a percent increase in diameter from baseline. Doppler ultrasound measures ICA velocity and diameter. The CON trial revealed that 30 min of sitting did not alter shear-mediated dilation (4.34 ± 1.37% to 3.44 ± 1.23%, P = 0.052). ICA dilation after exercise compared with preexercise levels increased in the ExSB trial (3.32 ± 1.37% to 4.74 ± 1.84%, P < 0.01), remained unchanged in the ExHV trial (4.07 ± 1.55% to 3.21 ± 1.48%, P = 0.07), but was elevated in the [Formula: see text] trial (3.35 ± 1.15% to 4.33 ± 2.12%, P = 0.04). Our results indicate that exercise-induced increases in cerebral shear may play a crucial role in improving cerebrovascular endothelial function after acute exercise in young adults.NEW & NOTEWORTHY We found that 30-min cycling (target intensity was 80% of the ventilatory threshold) with increasing shear of the internal carotid artery (ICA) enhanced transient hypercapnia-induced shear-mediated dilation of the ICA, reflecting improved cerebrovascular endothelial function. This enhancement of ICA dilation was diminished by suppressing the exercise-induced increase in ICA shear via hyperventilation. Our results indicate that increases in cerebral shear may be a key stimulus for improving cerebrovascular endothelial function after exercise in young adults.

Inspiratory resistance training transiently improves endothelium-dependent dilation in young adults

Introduction: Inspiratory resistance training (IRT) is a resisted breathing exercise originally devised to improve diaphragmatic strength. We have shown IRT to be a potent non-pharmacological therapy that yields significant reductions in resting blood pressure. When performed daily for 6 weeks, systolic blood pressure is reduced by ~9 mmHg, secondary to reductions in systemic vascular resistance. Whereas the effects of IRT on the vasculature have been described over the intermediate term, the acute responses that mediate these longer-term adaptations have not been fully characterized. Purpose: Our primary aim was to quantify the acute effects of a single bout of IRT on (endothelium-dependent dilation) EDD in healthy men and women. Secondarily, our goal was to determine the acute effects of IRT on arterial stiffness. Methods: Nitric oxide-mediated EDD and ischemia-induced maximal shear rate were assessed with brachial artery flow-mediated dilation (FMD), and arterial stiffness was assessed via carotid-femoral pulse wave velocity (PWV). Twenty healthy young adults (22.9 ± 3.4 years; 10 males, 10 females) were randomized to the experimental (IRT; 5 sets of 6 breaths at 50% of maximal inspiratory pressure with 1-minute rest intervals) and control (time-matched supine rest) conditions in a crossover design, with at least 48 hours between visits. FMD and PWV were performed before, 10 minutes after, and 40 minutes after the assigned intervention. Statistical analysis included repeated measures ANOVA with Sidak post hoc analyses. Results: All values are mean difference ± SD. There were no between-day differences in EDD at baseline (mean difference: 0.08 ± 3.03%; p=0.908). EDD was significantly increased from baseline at 10 minutes post-IRT (+1.86 ± 2.75%; p=0.025), but returned to baseline levels at 40 minutes post-IRT (-0.10 ± 3.00%; p=0.998). During the control condition, EDD was unchanged from baseline at 10 minutes post-rest and 40 minutes post-rest ( p=0.136). Lastly, maximal shear rate following 5 minutes of forearm blood flow occlusion was not different from baseline at any time point following IRT ( p=0.749) and thus, the change in EDD is not a result of a modified hyperemic response. However, in the control condition maximal shear rate was significantly lower at 40 minutes post-rest, relative to baseline (mean difference -9.94 ± 2.64 per second; p=0.005), although the reduced shear rate did not impact EDD at 40 minutes post-rest. Arterial stiffness was unchanged from baseline in response to IRT ( p=0.217) or the rest intervention ( p=0.150). Conclusions: In healthy young adult men and women, a single bout of IRT elicits a transient enhancement in EDD. The effect endures for at least 10 minutes but is extinguished at 40 minutes post IRT. Repeated acute enhancements in EDD may contribute to sustained IRT-related reductions in vascular resistance after 6 weeks of traini This work was supported by NIA/NIH Grant Number: 1R01AG065346-01A1 (EFB), NIH Training Grant Number: 5T32HL007249-44 (DT), and NIH/NHLBI Grant Number: 1K01HL153326-01 (DHC) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The association between cardiac magnetic resonance-derived aortic stiffness parameters and aortic dilation in young adults with bicuspid aortic valve: With and without coarctation of aorta

BackgroundBicuspid aortic valve (BAV) is associated with progressive aortic dilation. Studies in aortopathies have shown a correlation between increased aortic stiffness and aortic dilation. We aimed to evaluate aortic stiffness measures as predictors of progressive aortic dilation by cardiac magnetic resonance (CMR) in BAV patients. MethodsThis is a retrospective study of 49 patients with BAV (median age 21.1 years at first CMR visit) with ≥2 CMR at the Wisconsin Adult Congenital Heart Disease Program (WAtCH). Circumferential aortic strain, distensibility, and β-stiffness index were obtained from CMR-derived aortic root cine imaging, and aortic dimensions were measured at aortic root and ascending aorta. A linear mixed-model and logistic regression were used to identify important predictors of progressive aortic dilation. ResultsOver a median of 3.8 years follow-up, the annual growth rates of aortic root and ascending aorta dimensions were 0.25 and 0.16 mm/year, respectively. Aortic strain and distensibility decreased while β-stiffness index increased with age. Aortic root strain and distensibility were associated with progressive dilation of the ascending aorta. Baseline aortic root diameter was an independent predictor of >1 mm/year growth rate of the aortic root (adjusted OR 1.34, 95 % CI 1.03–1.74, p = 0.028). Most patients (61 %) had coexisting coarctation of aorta. Despite the higher prevalence of hypertension in patients with aortic coarctation, hypertension or coarctation had no effect on baseline aorta dimensions, stiffness, or progressive aortic dilation. ConclusionSome CMR-derived aortic stiffness parameters correlated with progressive aortic dilation in BAV and should be further investigated in larger and older BAV cohorts.

Short-term salicylate treatment improves microvascular endothelium-dependent dilation in young adults with major depressive disorder.

Reactive oxygen species (ROS)-mediated reductions in nitric oxide (NO)-dependent dilation are evident in adults with major depressive disorder (MDD); however, the upstream mechanisms remain unclear. Here, we hypothesized that nuclear factor-κB (NF-κB) activation-induced ROS production contributes to microvascular endothelial dysfunction in MDD. Thirteen treatment-naive adults with MDD (6 women; 19-23 yr) and 10 healthy nondepressed adults (HAs; 5 women; 20-25 yr) were tested before and after (open-label design) systemic NF-κB knockdown (nonacetylated salicylate; 3,000-4,500 mg/day × 4 days). Red cell flux (laser Doppler flowmetry) was measured during graded intradermal microdialysis perfusion of the endothelium-dependent agonist acetylcholine (ACh), alone and in combination with NO synthase inhibition [NG-nitro-l-arginine methyl ester (l-NAME)] or ROS scavenging (apocynin). Serum salicylate concentrations following treatment were not different between groups (22.8 ± 7.4 HAs vs. 20.8 ± 4.3 mg/dL MDD; P = 0.46). When compared with HAs, the NO-dependent component of ACh-induced dilation was blunted in adults with MDD before (P = 0.023), but not after (P = 0.27), salsalate treatment. In adults with MDD, the magnitude of improvement in endothelium-dependent dilation following salsalate treatment was inversely related to the degree of functional impairment at baseline (R2 = 0.43; P = 0.025). Localized ROS scavenging improved NO-dependent dilation before (P < 0.01), but not after (P > 0.05), salsalate treatment. Salsalate did not alter systemic concentrations of pro- or anti-inflammatory cytokines (all P > 0.05). These data suggest that NF-κB activation, via increased vascular ROS production, contributes to blunted NO-dependent dilation in young adults with MDD but otherwise free of clinical disease. These data provide the first direct evidence for a mechanistic role of vascular inflammation-associated endothelial dysfunction in human depression.NEW & NOTEWORTHY Our data indicate that short-term treatment with therapeutic doses of the nuclear factor-κB (NF-κB) inhibitor salsalate improved nitric oxide (NO)-mediated endothelium-dependent dilation in adults with major depressive disorder (MDD). In adults with MDD, acute localized scavenging of reactive oxygen species (ROS) with apocynin improved NO-dependent dilation before, but not after, salsalate administration. These data suggest that activation of NF-κB, in part via stimulation of vascular ROS production, contributes to blunted NO-mediated endothelium-dependent dilation in young adults with MDD.

"To measure is to know": no relationship between cerebrovascular and peripheral shear-mediated dilation in young adults.

"To measure is to know": no relationship between cerebrovascular and peripheral shear-mediated dilation in young adults.

Shear stress and cerebrovascular function during acute isometric exercise: the role of exercise intensity and aging

Introduction: Exercise reduces the risk of developing vascular dysfunction, implicated in the progression of cardiovascular and cerebrovascular diseases. However, our understanding of how exercise can be optimised for improvements in brain health with increasing age, is limited. In the peripheral vasculature, episodic increases in blood flow and shear-stress promote acute and chronic improvements in vascular function. At the brain, evidence is less clear. Increases in cerebral blood flow (CBF) and shear stress are observed with low-intensity exercise, and these responses are dampened in older compared with younger adults. Whether the CBF shear stress response is intensity- and age-dependent is not known. In older adults, attenuations in CBF during exercise may be related to impaired vascular function, or an attenuated response to increases in blood pressure (hysteresis). Our study aims to examine CBF during varying increases in exercise intensity using isometric handgrip exercise. It is hypothesised that higher intensity isometric exercise will be associated with increased blood pressure and CBF, including shear-mediated internal carotid artery (ICA) dilation in young adults, but not in older adults. We also hypothesise CBF will not be associated with changes in blood pressure during exercise in older adults.

Parental Smoking in Childhood and Brachial Artery Flow-Mediated Dilatation in Young Adults

Passive smoking has been associated with increased cardiovascular morbidity. The present study aimed to examine the long-term effects of childhood exposure to tobacco smoke on endothelium-dependent vasodilation in adults. The analyses were based on 2171 participants in the population-based Cardiovascular Risk in Young Finns (N=2067) and Childhood Determinants of Adult Health (N=104) studies who had measures of conventional risk factors (lipids, blood pressure, adiposity, socioeconomic status) and self-reported parental smoking status when aged 3 to 18 years at baseline. They were re-examined 19 to 27 years later when aged 28 to 45 years. Brachial artery flow-mediated dilatation was measured at follow-up with ultrasound. In analyses adjusting for age, sex, and childhood risk factors, flow-mediated dilatation was reduced among participants who had parents that smoked in youth compared to those whose parents did not smoke (Young Finns: 9.2 ± 0.1% (mean ± SEM) versus 8.6 ± 0.1%, P=0.001; Childhood Determinants of Adult Health: 7.4 ± 0.6% versus 4.9 ± 0.9%, P=0.04). These effects remained after adjustment for adult risk factors including own smoking status (Young Finns, P=0.003; Childhood Determinants of Adult Health, P=0.03). Parental smoking in youth is associated with reduced flow-mediated dilatation in young adulthood measured over 20 years later. These findings suggest that passive exposure to cigarette smoke among children might cause irreversible impairment in endothelium-dependent vasodilation.

Ageing uncompensated: exercise, nitric oxide and hypoxia

Ageing uncompensated: exercise, nitric oxide and hypoxia

Adiponectin is related with carotid artery intima-media thickness and brachial flow-mediated dilatation in young adults—The Cardiovascular Risk in Young Finns Study

Aims. Adiponectin may be involved in the pathogenesis of atherosclerosis. We investigated the relation of adiponectin on early functional and structural markers of subclinical atherosclerosis in a large population-based cohort of young men and women.Methods and results. We measured serum adiponectin using radioimmunoassay in 2,147 young adults (ages 24–39 years) participating in the Cardiovascular Risk in Young Finns Study. The subjects had ultrasound data on carotid intima-media thickness (IMT), carotid artery elasticity (n = 2,139) and brachial flow-mediated dilatation (FMD) (n = 1,996). In univariate analysis, adiponectin was inversely associated with IMT (r = −0.16, P < 0.0001) and directly with FMD (r = 0.12, P < 0.0001) and carotid elasticity (r = 0.20, P < 0.0001). The associations for IMT and FMD remained significant in multivariable models adjusted for age, sex, obesity indices, serum lipids, blood pressure, leptin, glucose, and C-reactive protein: IMT (β = −0.018 ± 0.005, P = 0.0002) and FMD (β = 0.72 ± 0.25, P = 0.004). The relation between adiponectin and carotid elasticity attenuated to non-significant after adjusting for waist circumference and systolic blood pressure.Conclusion. In young healthy adults, low serum adiponectin concentration is independently related with increased carotid IMT and attenuated brachial FMD, supporting the role of adiponectin in the pathogenesis of early atherosclerosis.

Predictors of Left Ventricular Dilatation in Young Adults (from the Bogalusa Heart Study)

Left ventricular (LV) dilatation may be an early sign of cardiac decompensation progressing to LV dysfunction. Determinants of LV dilatation in young asymptomatic adults are unknown. Five hundred six asymptomatic subjects (mean age 32 +/- 3 years) enrolled in the Bogalusa Heart Study underwent echocardiographic examination. LV dilatation (LV end-diastolic diameter >5.5 cm) as measured by M-mode echocardiography was found in 31 subjects (6%). Subjects with LV dilatation had greater body mass indexes (32 +/- 9 vs 27 +/- 6 kg/m2, p <0.0001), systolic (119 +/- 15 vs 112 +/- 12 mm Hg, p = 0.007) and diastolic (79 +/- 12 vs 75 +/- 9 mm Hg, p = 0.04) blood pressures, and LV mass (230 +/- 50 vs 123 +/- 39 g, p <0.0001). Age, gender, race, and metabolic parameters (glucose, insulin, and lipoprotein levels) did not differ significantly between the subjects with and without LV dilatation. After correction for age, gender, and race differences, adulthood obesity (body mass index >30 kg/m2) was associated with a threefold odds ratio (2.9, 95% confidence interval 1.4 to 6.1), and hypertension (defined as per the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure) was also associated with a threefold odds ratio (3.0, 95% confidence interval 1.2 to 7.1) for an increased incidence of LV dilatation. There was an incremental increase in LV end-diastolic dimension depending on the presence of hypertension or obesity, and subjects with obesity and hypertension in adulthood had the greatest degree of LV end-diastolic dimensions. In multiple regression analyses, body mass index in childhood was the only significant predictor of LV dilatation in adulthood (odds ratio 1.47, 95% confidence interval 1.03 to 2.09). In conclusion, obesity beginning in childhood and obesity and hypertension in young adulthood are predictors of LV dilatation in an otherwise healthy young adult population.

Adiponectin and Coronary Heart Disease: The Strong Heart Study

To the Editor: The adipocyte secreted protein, adiponectin, is of particular interest in metabolic and vascular disease because of its close associations with insulin sensitivity and obesity.1 Lower levels of adiponectin are associated with later development of type 2 diabetes.2 Recent observations from the Health Professionals Follow-Up Study3 suggest that lower adiponectin concentrations might also be associated with incident myocardial infarction, findings in keeping with prior observations in patients with end-stage renal failure.4 We examined prospective relationships of adiponectin to vascular disease in a case–control series selected from the Strong Heart Study (SHS). The SHS is the largest study of cardiovascular disease in American Indians, a group at particular risk of obesity and type 2 diabetes and in whom an increasing incidence of coronary heart disease (CHD) is seen.5 Cases and controls were selected from the SHS cohort.6 The SHS recruited 4549 volunteers of American Indian heritage from 3 geographic areas (Arizona, North and South Dakota, and Oklahoma).6 Volunteers (59% female) were invited to a study examination on three occasions (SH1, 1988 to 1992; SH2, 1993 to 1995; SH3, 1997 to 1999) and remained under continued surveillance for development of vascular disease as described previously.7,8 Because of availability of plasma samples, baseline data for this study were taken from the second examination (SH2), and participants with prevalent cardiovascular disease at SH2 (definite CHD and stroke), …

Capillary Rarefaction and Impaired Microvascular Dilatation in Young Adults with a Familial Predisposition to high Blood Pressure

Capillary Rarefaction and Impaired Microvascular Dilatation in Young Adults with a Familial Predisposition to high Blood Pressure

Sensitivity of psychiatric diagnosis based on the best estimate procedure.

A "best estimate" diagnosis is one made by expert clinicians on the basis of diagnostic information from direct interview conducted by another clinician plus information from medical records and from reports of family members. The authors address the question of whether the best estimate procedure can enhance the classification of psychiatric diagnoses of subjects who are interviewed directly. Four hundred seventy-five subjects were interviewed directly: 201 opiate-addicted probands who sought treatment from a university-based clinic and 274 of their spouses and/or first-degree relatives. Subjects were interviewed by trained clinical assessors using the Schedule for Affective Disorders and Schizophrenia and classified according to Research Diagnostic Criteria. Two psychologists independently diagnosed the same subjects by applying the best estimate procedure. Lifetime rates of major and minor depressive disorder, antisocial personality, alcoholism, and drug abuse were calculated. The rates of diagnoses made on the basis of direct interviews alone were compared with the rates of diagnoses made according to the best estimate procedure. Higher rates of diagnoses of all four disorders were made when the best estimate procedure was applied than when direct interview alone was used; the best estimate procedure also resulted in a minimal rate of false positives. The higher rate of diagnoses based on the best estimate procedure may represent an enhancement in the accuracy of psychiatric diagnoses or an increase in erroneous diagnoses. The authors consider the second possibility less likely.

Transient benign unilateral pupillary dilation in young adults.

Transient unilateral pupillary dilation occurred in four young adults who otherwise had normal clinical neurological examination results and normal cerebral arteriograms. The cause of this benign syndrome is unknown, but some cases may be variants of ophthalmoplegic migraine.