Insulin-Associated Weight Gain in Type 2 Diabetes Is Associated With Increases in Sedentary Behavior.

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Carotid artery vasoreactivity correlates with abdominal aortic vasoreactivity in young healthy individuals but not in patients with abdominal aortic aneurysm

BACKGROUND: Sympathetic stimulation of central arteries, such as coronary and carotid arteries, cause vasodilation in healthy subjects, but vasoconstriction in those with increased cardiovascular risk. This study compared vasoreactivity to sympathetic stimulation between abdominal aorta and carotid artery in healthy young individuals (young group, n = 20), in patients with abdominal aortic aneurysm (AAA group, n = 20) and in a healthy older group, age- and gender matched with AAA group (matched group, n = 18). METHOD: All subjects underwent cold pressor test, while performing concomitantly duplex ultrasound of abdominal aorta and carotid artery vasoreactivity. Observer-independent software was used to analyze and calculate magnitude and timing of maximum vasodilation or vasoconstriction. Pearson's correlation coefficient was calculated to investigate vasoreactivity between arteries. RESULTS: Carotid artery reactivity [Interquartile range 25%, Interquartile range 75%] did not significantly differ between the young, matched and AAA group (3.5% [1.4, 4.7], 2.6% [2.0, 4.1] and 2.2% [-1.9, 3.7], respectively, p = 0.301). Abdominal aortic responsiveness demonstrated larger differences between young (4.9% [-0.2, 8.4]), matched (3.3% [-2.5, 4.4]) and individuals with AAA (0.5% [-3.9, 4.1], p = 0.059). Pooled analysis showed a significant correlation between carotid and abdominal aortic vasoreactivity (r = 0.444, p = 0.001). Subgroup analyses demonstrated significant correlation between both arteries in young (r = 0.636, p = 0.003), but not matched (r = −0.040, p = 0.866) or AAA group (r = 0.410, p = 0.129). CONCLUSIONS: Sympathetic stimulation induces powerful vasodilation of the carotid artery and abdominal aorta, which is significantly correlated in healthy individuals. No such correlation is present in abdominal aortic aneurysm patients. This suggests the aneurysm alters local abdominal aorta vasoreactivity, but not the carotid artery

Left ventricular deformation and myocardial fibrosis in pediatric patients with Duchenne muscular dystrophy

Background: Left ventricular (LV) strain and rotation are emerging functional markers for early detection of LV dysfunction and have been associated with the burden of myocardial fibrosis in several disease states. This study examined the association between LV deformation (i.e., LV strain and rotation) and extent and location of LV myocardial fibrosis in pediatric patients with Duchenne muscular dystrophy (DMD). Methods and results: 34 pediatric patients with DMD underwent cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) to assess LV myocardial fibrosis. Offline CMR feature-tracking analysis was used to assess global and segmental longitudinal and circumferential LV strain, and LV rotation. Patients with fibrosis (n = 18, 52.9%) were older than those without fibrosis (14 ± 3 years (yrs) vs 11 ± 2 yrs., p = 0.01). There was no significant difference in LV ejection fraction (LVEF) between subjects with and without fibrosis (54 ± 6% vs 56 ± 4%, p = 0.18). However, lower endocardial global circumferential strain (GCS), but not LV rotation, was associated with presence of fibrosis (adjusted Odds Ratio 1.25 [95% CI 1.01–1.56], p = 0.04). Both GCS and global longitudinal strain correlated with the extent of fibrosis (r =.52, p = 0.03 and r =.75, p &lt; 0.01, respectively). Importantly, segmental strain did not seem to correspond to location of fibrosis. Conclusion: A lower global, but not segmental, strain is associated with presence and extent of LV myocardial fibrosis in pediatric DMD patients. Therefore, strain parameters might detect structural myocardial alterations, however currently more research is needed to evaluate its value (e.g., prognostic) in clinical practice.</p

Left ventricular strain-volume loops in bicuspid aortic valve disease:new insights in cardiomechanics

AIMS: By combining temporal changes in left ventricular (LV) global longitudinal strain (GLS) with LV volume, LV strain-volume loops can assess cardiac function across the cardiac cycle. This study compared LV strain-volume loops between bicuspid aortic valve (BAV) patients and controls, and investigated the loop’s prognostic value for clinical events.METHODS AND RESULTS: From a prospective cohort of congenital heart disease patients, BAV patients were selected and compared with healthy volunteers, who were matched for age and sex at group level. GLS7 analysis from apical views were used to construct strain-volume loops. Associations with clinical events, i.e. a composite of all-cause mortality, heart failure, arrhythmias and aortic valve replacement, were assessed by Cox regression. 113 BAV patients were included (median age 32 years, 40% female). BAV patients demonstrated lower Sslope (0.21%/mL, [Q1-Q3: 0.17-0.28] vs. 0.27%/mL [0.24-0.34], p&lt;0.001) and ESslope (0.19%/mL [0.12-0.25] vs. 0.29%/mL [0.21-0.43], p&lt;0.001) compared to controls, but also greater uncoupling during early (0.48±1.29 vs. 0.06±1.2, p=0.018) and late diastole (0.66±1.01 vs -0.06±1.09, p&lt;0.001). Median follow-up duration was 9.9 [9.3-10.4] years. Peak aortic jet velocity (HR 1.22, p=0.03), enlarged left atrium (HR 3.16, p=0.003), E/e’ ratio (HR 1.17, p=0.002), GLS (HR 1.16, p=0.008) and ESslope (HR 0.66, p=0.04) were associated with the occurrence of clinical events.CONCLUSION: Greater uncoupling and lower systolic and diastolic slopes were observed in BAV patients compared to healthy controls, suggesting presence of altered LV cardiomechanics. Moreover, lower ESslope was associated with clinical events, highlighting the strain-volume loop’s potential as prognostic marker

Impact of retrograde shear rate on brachial and superficial femoral artery flow-mediated dilation in older subjects

An inverse, dose-dependent relationship between retrograde shear rate and brachial artery endothelial function exists in young subjects. This relationship has not been investigated in older adults, who have been related to lower endothelial function, higher resting retrograde shear rate and higher risk of cardiovascular disease. Aim To investigate the impact of a step-wise increase in retrograde shear stress on flow-mediated dilation in older males in the upper and lower limbs. Methods Fifteen older (68±9 years) men reported to the laboratory 3 times. We examined brachial artery flow-mediated dilation before and after 30-minutes exposure to cuff inflation around the forearm at 0, 30 and 60 mmHg, to manipulate retrograde shear rate. Subsequently, the 30-minute intervention was repeated in the superficial femoral artery. Order of testing (vessel and intervention) was randomised. Results Increases in cuff pressure resulted in dose-dependent increases in retrograde shear in both the brachial and superficial femoral artery in older subjects. In both the brachial and the superficial femoral artery, no change in endothelial function in response to increased retrograde shear was observed in older males (‘time’ P=0.274, ‘cuff*time P=0.791’, ‘cuff*artery*time P=0.774’). Conclusion In contrast with young subjects, we found that acute elevation in retrograde shear rate does not impair endothelial function in older humans. This may suggest that subjects with a priori endothelial dysfunction are less responsive or requires a larger shear rate stimulus to alter endothelial function

Left ventricular strain-volume loops in bicuspid aortic valve disease:new insights in cardiomechanics

AIMS: By combining temporal changes in left ventricular (LV) global longitudinal strain (GLS) with LV volume, LV strain-volume loops can assess cardiac function across the cardiac cycle. This study compared LV strain-volume loops between bicuspid aortic valve (BAV) patients and controls, and investigated the loop’s prognostic value for clinical events.METHODS AND RESULTS: From a prospective cohort of congenital heart disease patients, BAV patients were selected and compared with healthy volunteers, who were matched for age and sex at group level. GLS7 analysis from apical views were used to construct strain-volume loops. Associations with clinical events, i.e. a composite of all-cause mortality, heart failure, arrhythmias and aortic valve replacement, were assessed by Cox regression. 113 BAV patients were included (median age 32 years, 40% female). BAV patients demonstrated lower Sslope (0.21%/mL, [Q1-Q3: 0.17-0.28] vs. 0.27%/mL [0.24-0.34], p&lt;0.001) and ESslope (0.19%/mL [0.12-0.25] vs. 0.29%/mL [0.21-0.43], p&lt;0.001) compared to controls, but also greater uncoupling during early (0.48±1.29 vs. 0.06±1.2, p=0.018) and late diastole (0.66±1.01 vs -0.06±1.09, p&lt;0.001). Median follow-up duration was 9.9 [9.3-10.4] years. Peak aortic jet velocity (HR 1.22, p=0.03), enlarged left atrium (HR 3.16, p=0.003), E/e’ ratio (HR 1.17, p=0.002), GLS (HR 1.16, p=0.008) and ESslope (HR 0.66, p=0.04) were associated with the occurrence of clinical events.CONCLUSION: Greater uncoupling and lower systolic and diastolic slopes were observed in BAV patients compared to healthy controls, suggesting presence of altered LV cardiomechanics. Moreover, lower ESslope was associated with clinical events, highlighting the strain-volume loop’s potential as prognostic marker

Impact of sympathetic nervous system activity on post-exercise flow-mediated dilatation in humans

Transient reduction in vascular function following systemic large muscle group exercise has previously been reported in humans. The mechanisms responsible are currently unknown. We hypothesised that sympathetic nervous system activation, induced by cycle ergometer exercise, would contribute to post-exercise reductions in flow-mediated dilatation (FMD). Ten healthy male subjects (28 ± 5 years) undertook two 30 min sessions of cycle exercise at 75% HRmax. Prior to exercise, individuals ingested either a placebo or an α1-adrenoreceptor blocker (prazosin; 0.05 mg kg−1). Central haemodynamics, brachial artery shear rate (SR) and blood flow profiles were assessed throughout each exercise bout and in response to brachial artery FMD, measured prior to, immediately after and 60 min after exercise. Cycle exercise increased both mean and antegrade SR (P < 0.001) with retrograde SR also elevated under both conditions (P < 0.001). Pre-exercise FMD was similar on both occasions, and was significantly reduced (27%) immediately following exercise in the placebo condition (t-test, P = 0.03). In contrast, FMD increased (37%) immediately following exercise in the prazosin condition (t-test, P = 0.004, interaction effect P = 0.01). Post-exercise FMD remained different between conditions after correction for baseline diameters preceding cuff deflation and also post-deflation SR. No differences in FMD or other variables were evident 60 min following recovery. Our results indicate that sympathetic vasoconstriction competes with endothelium-dependent dilator activity to determine post-exercise arterial function. These findings have implications for understanding the chronic impacts of interventions, such as exercise training, which affect both sympathetic activity and arterial shear stress

Acute black tea consumption improves cutaneous vascular function in healthy middle-aged humans.

BACKGROUND & AIMS: Dietary flavonoids, such as those present in black tea, are associated with reduced risk of cardiovascular disease (CVD), possibly through improving nitric oxide (NO) mediated vascular function. The aim of this study was to examine the effect of acute black tea ingestion on cutaneous microvascular function. METHODS: Twenty healthy participants (58 ± 5 y, 9 men) attended two experimental trials (tea, placebo), 7-days apart in a randomised, controlled, double-blind, cross-over design. Participants ingested a single dose of 200 ml black tea or placebo, followed by assessment of forearm cutaneous perfusion using laser-Doppler flowmetry (LDF) using three distinct heating protocols, enabling us to distinguish between axon- and endothelium-dependent vasodilation: 1. rapid 42°C, 2. rapid 39°C and 3. gradual 42°C. On the contralateral arm, full-field laser perfusion imaging (FLPI) was used to assess forearm perfusion during gradual 42°C. Data were presented as cutaneous vascular conductance (CVC; flux/mean arterial pressure, MAP) and CVC expressed as a percentage of maximal CVC (%CVCmax). RESULTS: Rapid local heating to 39°C or 42°C demonstrated no effect of tea for flux, CVC or %CVCmax (all P > 0.05). Gradual local heating to 42 °C, however, produced a higher skin blood flow following black tea ingestion for absolute CVC (P = 0.04) when measured by LDF, and higher absolute flux (P < 0.001) and CVC (P < 0.001) measured with FLPI. No effect of tea was found for %CVCmax when assessed by either LDF or FLPI. CONCLUSIONS: Acute tea ingestion enhanced cutaneous vascular responses to gradual local heating to 42 °C in healthy, middle-aged participants, possibly through a mechanism related to activation of endothelium-derived chemical mediators, such as NO. These improvements may contribute to the cardiovascular health benefits of regular tea ingestion