Endothelium-derived nitric oxide regulates arterial elasticity in human arteries in vivo

Correlations of the Circadian Rhythmicity of Blood Pressure With Erectile Dysfunction

Erectile dysfunction (ED) and cardiovascular diseases (CVD) share common pathophysiological mechanisms. This study aimed to assess the relationship between ED and its severity with the risk of developing CVD by analyzing changes in the circadian blood pressure (BP) rhythm. In the study, 24-h BP levels of 192 (94 with ED and 98 controls) participants with no history of CVD were evaluated using an ambulatory blood pressure monitoring (ABPM) device. The International Index of Erectile Function (IIEF) questionnaire was used to assess the ED severity in the study group. ABPM measurements revealed higher BP values among the ED group. The nondipper pattern was significantly more frequent in the ED group compared to the controls (56.2% vs. 77.1%, p < 0.01). Blood pressure variability parameters, including systolic standard deviation (SD) and average real variability (ARV), were notably higher in the ED group (16.3 ± 3.9 vs. 14.6 ± 4.3, p < 0.01 and 13.39 ± 7.24 vs. 11.5 ± 2.1, p < 0.01, respectively). Furthermore, parameters reflecting arterial stiffness including pulse pressure index (PPI) and ambulatory arterial stiffness index (AASI) were higher in the ED group (0.81 ± 0.33 vs. 0.73 ± 0.18, p = 0.03 and 0.71 ± 0.09 vs. 0.59 ± 0.17, p = 0.014, respectively). Both AASI and ARV were significantly correlated with the severity of ED. This study suggests a significant association between ED severity and altered blood pressure patterns which in part explains the increased risk of CVD among individuals with ED.

Regulation of Cerebral Blood Flow Velocity by Transcutaneous Electrical Nerve Stimulation: A Preliminary Study

OBJECTIVES

An excessive and abrupt increase in cerebral blood flow may cause blood vessel damage, leading to stroke. Therefore, appropriate methods to immediately regulate blood flow velocity are important. Through an analysis of 31 healthy adults, we therefore investigated whether stimulating the common carotid artery (CCA) using transcutaneous electrical nerve stimulation (TENS) could modulate blood flow velocity in the CCA.

METHODS

Three stimulation intensities (below-threshold, threshold, and above-threshold) were applied in a random order. Blood velocity changes were examined by the measurement of peak systolic velocity (PSV) with Doppler ultrasound before, during, and after TENS stimulation. To evaluate arterial stiffness, pulse wave velocity (PWV) was calculated using CCA diameter, and blood pressure was measured before and after stimulation.

RESULTS

PSV changes in the below-threshold level were significant (p = 0.028). The PSV after below-threshold stimulation was significantly decreased by 2.23% compared to that before stimulation (p = 0.031). PWV showed no significant differences; however, a nonsignificant increase was observed immediately after stimulation only in the above-threshold condition. Above-threshold stimulation can increase vascular tone by activating the sympathetic nerve, possibly triggering vasoconstriction.

CONCLUSIONS

A decrease in blood flow velocity may not be expected upon the above-threshold stimulation. In contrast, the below-threshold stimulation immediately reduces blood flow velocity, without significantly affecting hemodynamic function, such as arterial flexibility. Therefore, this short-term and low electrical stimulation technique can help to lower vascular resistance and prevent vascular damage from rapid blood flow velocity.

Test-retest reliability of Doppler ultrasound-based leg blood flow assessments during exercise in patients with chronic obstructive pulmonary disease

Doppler ultrasound may be used to assess leg blood flow (Q ̇ leg ${{\dot{Q}}_{{\mathrm{leg}}}}$ ), but the reliability of this method remains unexplored in patients with chronic obstructive pulmonary disease (COPD), where between-subject variability may be larger than healthy due to peripheral vascular changes. This study aimed to investigate the reliability of Doppler ultrasound in quantifyingQ ̇ leg ${{\dot{Q}}_{{\mathrm{leg}}}}$ during single-leg knee-extensor exercise (KEE) in COPD patients compared with those obtained from healthy matched controls. In this case-control study, 16 participants with COPD were matched based on sex and age with 16 healthy controls. All participants underwent measurement ofQ ̇ leg ${{\dot{Q}}_{{\mathrm{leg}}}}$ using Doppler ultrasound in a KEE set-up at various intensities on two separate visits. Confounding factors onQ ̇ leg ${{\dot{Q}}_{{\mathrm{leg}}}}$ were controlled for, and the ultrasound scans were consistently performed by the same sonographer. During exercise, smallest real difference (SRD) ranged from 367 mL to 583 mL in COPD and 438 mL to 667 mL in the control group. The coefficient of variation (CV) ranged from 7.9% to 14.3% in COPD and 9.4% to 10.4% in the control group. The intraclass correlation coefficient ranged from 0.75 to 0.92 in COPD and 0.67 to 0.84 in the control group. CV was lower in the control group during exercise at 0 W, but apart from that, reliability was not different between groups during exercise. Doppler ultrasound showed nearly equal reliability when evaluatingQ ̇ leg ${{\dot{Q}}_{{\mathrm{leg}}}}$ in COPD patients and healthy individuals with a CV below 15% during exercise for both groups. HIGHLIGHTS: What is the central question of this study? What is the between-day reliability of Doppler ultrasound when quantifying leg blood flow during single-leg knee-extensor exercise in COPD patients compared to healthy matched controls? What is the main finding and its importance? This study demonstrates a coefficient of variation ranging from 7.9 to 14.3% during single-leg knee-extensor exercise for between-day reliability when applying Doppler ultrasound to assess leg blood flow in patients with COPD. Furthermore, it offers insights into the peripheral circulatory constraints in COPD, as evidenced by diminished leg blood flow. This study is the first of its kind to evaluate the reliability of Doppler ultrasound in the assessment of the peripheral circulation during exercise in COPD.

Uninterrupted prolonged sitting and arterial stiffness: moderating effect of prior aerobic exercise in physically active adults

PURPOSE

Prolonged sitting acutely increases arterial stiffness, with interruption strategies only providing limited success in offsetting these rises. Acute aerobic exercise is a potent stimulus to decrease arterial stiffness. However, limited information exists on the effectiveness of acute exercise to maintain arterial stiffness when performed prior to prolonged sitting, particularly within physically active individuals.

METHODS

Using a randomized crossover design, 22 young, active individuals (50% female) performed two conditions 30 min of walking at 55-65% of heart rate reserve (EX) and 30 min of standing (STAND) followed by 2.5-h of sitting. Brachial-femoral (bfPWV) and femoral-ankle pulse wave velocity (faPWV) were assessed at Baseline, post-exercise and pre-sitting (Pre), and post-sitting (Post) as estimates of central and peripheral arterial stiffness, respectively.

RESULTS

For bfPWV, no interaction, condition, or time effects were observed. For faPWV, an interaction was present (p < 0.001); compared to Baseline, there was a 6.1% decrease for EX (- 0.4 m/s, p < 0.001) and a 4.6% increase for STAND (0.3 m/s, p = 0.016) for STAND such that there was an 11.3% difference between conditions at Pre (0.7 m/s, p < 0.001). From Pre to Post, EX then increased by 11.7% (0.9 m/s p < 0.001) while STAND remained unchanged, resulting in no difference between conditions (0.1 m/s, p = 0.569).

CONCLUSIONS

While aerobic exercise resulted in a significant decrease in faPWV prior to sitting, the prior exercise bout did not confer a protective effect against the deleterious effects of uninterrupted sitting. Future work should investigate the combined effect of prior exercise and sitting interruption strategies on markers of arterial stiffness.

Acute effects of low-intensity one-legged electrical muscle stimulation on arterial stiffness in experimental and control limbs

The aim of this study was to examine the acute effects of low-intensity one-legged electrical muscle stimulation (EMS) for skeletal muscle on arterial stiffness in EMS and non-EMS legs. Eighteen healthy subjects received two different protocols (Control (CT) and Experimental (ET) trials) in random order on separate days. EMS was applied to the left lower limb at 4 Hz for 20 min at an intensity corresponding to an elevation in pulse rate of approximately 15 beats/min (10.9 ± 5.1% of heart rate reserve). Before and after the experiment, arterial stiffness parameters in the control right leg (CRL) and control left leg (CLL) in CT and non-EMS leg (NEL) and EMS leg (EL) in ET were assessed by pulse wave velocity (baPWV, faPWV) and cardio-ankle vascular index (CAVI). No significant changes in all parameters were observed in either leg in CT. Conversely, in ET, low-intensity, single-leg EMS significantly reduced CAVI, baPWV, and faPWV in the EL, but not in the NEL. Acute, low-intensity single-leg EMS reduces arterial stiffness only in the EL. These data support our idea that physical movement-related regional factors rather than systematic factors are important for inducing acute reductions in arterial stiffness.

Correlation between the triglyceride-glucose index and arterial stiffness in Japanese individuals with normoglycaemia: a cross-sectional study

BACKGROUND

The association between the triglyceride-glucose (TyG) index and arterial stiffness in individuals with normoglycaemia remains unclear. We aimed to evaluate the relationship between the TyG index and arterial stiffness in Japanese individuals with normoglycaemia, providing additional evidence for predicting early arterial stiffness.

METHODS

This study included 15,453 adults who participated in the NAGALA Physical Examination Project of the Murakami Memorial Hospital in Gifu, Japan, from 2004 to 2015. Data on clinical demographic characteristics and serum biomarker levels were collected. The TyG index was calculated from the logarithmic transformation of fasting triglycerides multiplied by fasting glucose, and arterial stiffness was measured using the estimated pulse wave velocity calculated based on age and mean blood pressure. The association between the TyG index and arterial stiffness was analysed using a logistic regression model.

RESULTS

The prevalence of arterial stiffness was 3.2% (500/15,453). After adjusting for all covariates, the TyG index was positively associated with arterial stiffness as a continuous variable (adjusted odds ratio (OR) = 1.86; 95% Confidence Interval = 1.45-2.39; P<0.001). Using the quartile as the cutoff point, a regression analysis was performed for arterial stiffness when the TyG index was converted into a categorical variable. After adjusting for all covariates, the OR showed an upward trend; the trend test was P<0.001. Subgroup analysis revealed a positive association between the TyG index and arterial stiffness in Japanese individuals with normoglycaemia and different characteristics.

CONCLUSION

The TyG index in Japanese individuals with normoglycaemia is significantly correlated with arterial stiffness, and the TyG index may be a predictor of early arterial stiffness.

The effect of successful lower extremity revascularization on aortic stiffness in patients with peripheral arterial disease

OBJECTIVE

Peripheral arterial disease (PAD) is a global health problem and associated with poor outcomes. It causes increased arterial stiffness. The association of PAD with aortic arterial stiffness was investigated in previous studies. However, there is limited data regarding the effect of peripheral revascularization on arterial stiffness. The aim of our study is to investigate the effect of peripheral revascularization on aortic stiffness parameters in patients with symptomatic PAD.

METHODS

A total of 48 patients with PAD who underwent peripheral revascularization were included in the study. Echocardiography was performed before and after the procedure, and aortic stiffness parameters were obtained by using aortic diameters and arterial blood pressure measurements.

RESULTS

Post-procedural aortic strain (5.1 [1.3-14] vs. 6.3 [2.8-6.3], p = 0.009) and aortic distensibility (0.2 [0.0-0.9] vs. 0.3 [0.1-1.1], p = 0.001) measurements were significantly increased compared to pre-procedural values. Patients were also compared according to the lesion laterality, site and treatment methods. It was found that the change in aortic strain (p = 0.031) and distensibility (p = 0.043) were significantly higher in unilateral lesion compared to bilateral lesion. Also, the change in aortic strain (p = 0.042) and distensibility (p = 0.033) were significantly higher in iliac site lesion compared to superficial femoral artery (SFA) site lesion. Moreover, the change in aortic strain was significantly higher (p = 0.013) in patients treated with stent compared to only balloon angioplasty.

CONCLUSION

Our study showed that successful percutaneous revascularization significantly reduced aortic stiffness in PAD. The change in aortic stiffness was significantly higher in unilateral lesions, iliac site lesions and stent-treated lesions.

The 24-h activity cycle and cardiovascular outcomes: establishing biological plausibility using arterial stiffness as an intermediate outcome

This review proposes a biologically plausible working model for the relationship between the 24-h activity cycle (24-HAC) and cardiovascular disease. The 24-HAC encompasses moderate-to-vigorous physical activity (MVPA), light physical activity, sedentary behavior (SB), and sleep. MVPA confers the greatest relative cardioprotective effect, when considering MVPA represents just 2% of the day if physical activity guidelines (30 min/day) are met. While we have well-established guidelines for MVPA, those for the remaining activity behaviors are vague. The vague guidelines are attributable to our limited mechanistic understanding of the independent and additive effects of these behaviors on the cardiovascular system. Our proposed biological model places arterial stiffness, a measure of vascular aging, as the key intermediate outcome. Starting with prolonged exposure to SB or static standing, we propose that the reported transient increases in arterial stiffness are driven by a cascade of negative hemodynamic effects following venous pooling. The subsequent autonomic, metabolic, and hormonal changes further impair vascular function. Vascular dysfunction can be offset by using mechanistic-informed interruption strategies and by engaging in protective behaviors throughout the day. Physical activity, especially MVPA, can confer protection by chronically improving endothelial function and associated protective mechanisms. Conversely, poor sleep, especially in duration and quality, negatively affects hormonal, metabolic, autonomic, and hemodynamic variables that can confound the physiological responses to next-day activity behaviors. Our hope is that the proposed biologically plausible working model will assist in furthering our understanding of the effects of these complex, interrelated activity behaviors on the cardiovascular system.

Association of baseline and dynamic arterial stiffness status with dyslipidemia: a cohort study

Background and aims

Dyslipidemia is known to contribute to arterial stiffness, while the inverse association remains unknown. This study aimed to explore the association of baseline arterial stiffness and its changes, as determined by brachial-ankle pulse wave velocity (baPWV), with dyslipidemia onset in the general population.

Methods

This study enrolled participants from Beijing Health Management Cohort using measurements of the first visit from 2012 to 2013 as baseline, and followed until the dyslipidemia onset or the end of 2019. Unadjusted and adjusted Cox proportional regression models were used to evaluate the associations of baseline baPWV and baPWV transition (persistent low, onset, remitted and persistent high) with incident dyslipidemia.

Results

Of 4362 individuals (mean age: 55.5 years), 1490 (34.2%) developed dyslipidemia during a median follow-up of 5.9 years. After adjusting for potential confounders, participants with elevated arterial stiffness at baseline had an increased risk of dyslipidemia (HR, 1.194; 95% CI, 1.050-1.358). Compared with persistent low baPWV, new-onset and persistent high baPWV were associated with a 51.2% and 37.1% excess risk of dyslipidemia.

Conclusion

The findings indicated that arterial stiffness is an early risk factor of dyslipidemia, suggesting a bidirectional association between arterial stiffness and lipid metabolism.

The association of moderate-to-vigorous physical activity and sedentary behaviour with abdominal aortic calcification

BACKGROUND AND AIMS

The increasing prevalence of metabolic and cardiovascular diseases poses a significant challenge to global healthcare systems. Regular physical activity (PA) is recognized for its positive impact on cardiovascular risk factors. This study aimed to investigate the relationship between moderate-to-vigorous physical activity (MVPA), sedentary behavior (SB), and abdominal aortic calcification (AAC) using data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

The study used data from NHANES participants aged 40 and above during the 2013-2014 cycle. AAC scores were assessed using the Kauppila scoring system, and MVPA and SB were self-reported. Sociodemographic variables were considered, and multivariable linear regression models were used to analyze associations between MVPA, SB, and AAC scores. Subgroup analyses were conducted based on age, sex, BMI, hypertension, and diabetes.

RESULTS

The study included 2843 participants. AAC prevalence was higher in older age groups, smokers, and those with diabetes or hypertension. Lower socioeconomic status was associated with higher AAC prevalence. Individuals engaged in any level of MVPA exhibited lower AAC rates compared to inactive individuals. Not engaging in occupational MVPA (β = 0.46, 95% confidence interval = 0.24‒0.67, p < .001) and prolonged SB (β = 0.28, 95% confidence interval = 0.04‒0.52, p = .023) were associated with higher AAC scores. However, no significant associations were found for transportation and leisure time MVPA. Subgroup analysis revealed age and hypertension as effect modifiers in the MVPA-AAC relationship.

CONCLUSIONS

This study highlights the potential benefits of engaging in occupational MVPA and reducing SB in mitigating AAC scores, particularly among older individuals and those with hypertension.

Foot Temperature by Infrared Thermography in Patients with Peripheral Artery Disease before and after Structured Home-Based Exercise: A Gender-Based Observational Study

Decreased arterial perfusion is a typical condition of patients with peripheral artery disease (PAD), with the microvascular picture particularly present among women. This observational study aimed to detect foot perfusion changes by infrared thermography (IRT) after a home-based exercise program in both sexes. A total of 76 PAD patients with claudication (72 ± 4 years; 52 males) were enrolled in a structured in-home exercise program composed of two daily 8 min interval walking sessions (1:1 walk:rest ratio) with progressively increasing speed. Outcome measures collected at baseline (T0) and at each hospital visit after 5 weeks, 12 weeks and 20 weeks included foot temperature measured by IRT (anterior tibial, posterior tibial, dorsalis pedis and arcuate artery regions), ankle brachial index and the 6 min walking test. After 20 weeks, foot temperature in both limbs showed a significant increasing trend, with a mean variation of 1.3 °C for the more impaired limb and 0.9 °C for the contralateral limb (t = 8.88, p < 0.001 and t = 5.36; p < 0.001, respectively), with significant changes occurring after 5 weeks of training. The sex-oriented analysis did not highlight any significant difference, with an improvement of mean foot temperature of 1.5 ± 0.6 °C in females versus 1.2 ± 0.5 °C in males (p = 0.42). Ankle brachial index and performance also significantly improved over time (p < 0.001) without gender differences. In patients with PAD, a structured low-intensity exercise program significantly improved foot temperature and exercise capacity without any sex-related difference.

Matrix stiffness, endothelial dysfunction and atherosclerosis

Atherosclerosis (AS) is the leading cause of the human cardiovascular diseases (CVDs). Endothelial dysfunction promotes the monocytes infiltration and inflammation that participate fundamentally in atherogenesis. Endothelial cells (EC) have been recognized as mechanosensitive cells and have different responses to distinct mechanical stimuli. Emerging evidence shows matrix stiffness-mediated EC dysfunction plays a vital role in vascular disease, but the underlying mechanisms are not yet completely understood. This article aims to summarize the effect of matrix stiffness on the pro-atherosclerotic characteristics of EC including morphology, rigidity, biological behavior and function as well as the related mechanical signal. The review also discusses and compares the contribution of matrix stiffness-mediated phagocytosis of macrophages and EC to AS progression. These advances in our understanding of the relationship between matrix stiffness and EC dysfunction open the avenues to improve the prevention and treatment of now-ubiquitous atherosclerotic diseases.

Acute beetroot juice reduces blood pressure in young Black and White males but not females

A complex interplay of social, lifestyle, and physiological factors contribute to Black Americans having the highest blood pressure (BP) in America. One potential contributor to Black adult's higher BP may be reduced nitric oxide (NO) bioavailability. Therefore, we sought to determine whether augmenting NO bioavailability with acute beetroot juice (BRJ) supplementation would reduce resting BP and cardiovascular reactivity in Black and White adults, but to a greater extent in Black adults. A total of 18 Black and 20 White (∼equal split by biological sex) young adults completed this randomized, placebo-controlled (nitrate (NO3-)-depleted BRJ), crossover design study. We measured heart rate, brachial and central BP, and arterial stiffness (via pulse wave velocity) at rest, during handgrip exercise, and during post-exercise circulatory occlusion. Compared with White adults, Black adults exhibited higher pre-supplementation resting brachial and central BP (Ps ≤0.035; e.g., brachial systolic BP: 116(11) vs. 121(7) mmHg, P = 0.023). Compared with placebo, BRJ (∼12.8 mmol NO3-) reduced resting brachial systolic BP similarly in Black (Δ-4±10 mmHg) and White (Δ-4±7 mmHg) adults (P = 0.029). However, BRJ supplementation reduced BP in males (Ps ≤ 0.020) but not females (Ps ≥ 0.299). Irrespective of race or sex, increases in plasma NO3- were associated with reduced brachial systolic BP (ρ = -0.237, P = 0.042). No other treatment effects were observed for BP or arterial stiffness at rest or during physical stress (i.e., reactivity); Ps ≥ 0.075. Despite young Black adults having higher resting BP, acute BRJ supplementation reduced systolic BP in young Black and White adults by a similar magnitude, an effect that was driven by males.

Exercise-based functional recovery from severe upper extremity arterial disease due to bilateral subclavian artery obstruction in a person with giant cell arteritis

We report the case of a 71-year-old woman diagnosed with giant cell arteritis with bilateral subclavian and axillary obstruction and severe arm claudication that occurred 3 months earlier and was non-regressed after corticosteroids. Before possible revascularization, the patient was initiated to a personalized home-based graded exercise program including walking, hand-bike pedaling, and muscle strength training. During the 9 months of treatment, the patient progressively improved radial pressure values (10 to 85 mmHg), hand temperature values by infrared-thermography (+2.1 °C), arm endurance, and forearm muscle oxygenation by near-infrared spectroscopy. Home-based graded exercise proved to be a noninvasive option for upper limb claudication.

Associations between physical activity and cardiorespiratory fitness with vascular health phenotypes in older adults: a cross-sectional study

Objective: We investigated the associations between physical activity (PA) and cardiorespiratory fitness (CRF) with vascular health phenotypes in community-dwelling older adults. Methods: This cross-sectional study included 82 participants (66.8 ± 5.2 years; 81% females). Moderate-to-vigorous physical activity (MVPA) was assessed using accelerometers, and CRF was measured using the distance covered in the 6-min walk test (6MWT). The vascular health markers were as follows: i) arterial function measured as aortic pulse wave velocity (aPWV) estimated using an automatic blood pressure device; and ii) arterial structure measured as the common carotid intima-media thickness (cIMT). Using a combination of normal cIMT and aPWV values, four groups of vascular health phenotypes were created: normal aPWV and cIMT, abnormal aPWV only, abnormal cIMT only, and abnormal aPWV and cIMT. Multiple linear regression was used to estimate the beta coefficients (β) and their respective 95% confidence intervals (95% CI) adjusting for BMI, and medication for diabetes, lipid, and hypertension, sex, age, and blood pressure. Results: Participants with abnormal aPWV and normal cIMT (β = -53.76; 95% CI = -97.73--9.78 m; p = 0.017), and participants with both abnormal aPWV and cIMT (β = -71.89; 95% CI = -125.46--18.31 m; p = 0.009) covered less distance in the 6MWT, although adjusting for age, sex and blood pressure decreased the strength of the association with only groups of abnormal aPWV and cIMT covering a lower 6MWT distance compared to participants with both normal aPWV and cIMT (β = -55.68 95% CI = -111.95-0.59; p = 0.052). No associations were observed between MVPA and the vascular health phenotypes. Conslusion: In summary, poor CRF, but not MVPA, is associated with the unhealthiest vascular health phenotype (abnormal aPWV/cIMT) in older adults.

Emerging Roles of Endothelial Nitric Oxide in Preservation of Cognitive Health

eNOS (endothelial nitric oxide synthase) is critically important enzyme responsible for regulation of cardiovascular homeostasis. Under physiological conditions, constitutive eNOS activity and production of endothelial nitric oxide (NO) exert essential neurovascular protective functions. In this review, we first discuss the roles of endothelial NO in prevention of neuronal amyloid accumulation and formation of neurofibrillary tangles, hallmarks of Alzheimer disease pathology. Next, we review existing evidence suggesting that NO released from endothelium prevents activation of microglia, stimulates glycolysis in astrocytes, and increases biogenesis of mitochondria. We also address major risk factors for cognitive impairment including aging and ApoE4 (apolipoprotein 4) genotype with focus on their detrimental effects on eNOS/NO signaling. Relevant to this review, recent studies suggested that aged eNOS heterozygous mice are unique model of spontaneous cerebral small vessel disease. In this regard, we review contribution of dysfunctional eNOS to deposition of Aβ (amyloid-β) into blood vessel wall leading to development of cerebral amyloid angiopathy. We conclude that endothelial dysfunction manifested by the loss of neurovascular protective functions of NO may significantly contribute to development of cognitive impairment.

Protocol for a study on Sitting with Interruption and Whole-Body Cardiovascular Health (SWITCH) in middle-aged adults

BACKGROUND

Sedentary behavior (SB) is a biologically distinct yet understudied cardiovascular disease risk (CVD) factor. However, specific public health policy regarding the optimal strategy for SB interruption is unavailable. This paper outlines the protocol for part I of the Sitting with Interruption and Whole-Body Cardiovascular Health (SWITCH) study, including the rationale, objectives, methodology, and next steps. We additionally detail practical considerations that went into the development of the NIH R01 grant supporting this research.

METHODS

Healthy men and women (n = 56, aged 36-55) who are inactive (<90 min/wk. of moderate-to-vigorous intensity physical activities for past 3 months) and sedentary (sitting for >8 h/day), will be recruited for this randomized crossover trial. Specifically, participants will complete the following 4-h conditions: (i) SB with once/h 5 min walk break; (ii) SB with once/h 15 min stand break; (iii) SB with twice/h breaks (alternating 5 min walk and 15 min stand); and (iv) SB with no breaks (i.e., control). Focus group discussions will refine our socioecological SB reduction model.

RESULTS

The primary outcome will be change in aortic arterial stiffness (i.e., pulse wave velocity; PWV, m/s) for each substitution strategy relative to the control (SB with no breaks) condition.

CONCLUSIONS

The outcomes from this study will facilitate the design of a subsequent randomized controlled trial to test a mechanism-informed, feasible SB-reduction intervention and support the development of SB policy.

Complement factors D and C3 cross-sectionally associate with arterial stiffness, but not independently of metabolic risk factors: The Maastricht Study

BACKGROUND

Arterial stiffness predicts cardiovascular outcomes. The complement system, particularly the alternative complement pathway, has been implicated in cardiovascular diseases. We herein investigated the associations of factor D, the rate-limiting protease of the alternative pathway, and C3, the central complement component, with arterial stiffness.

METHODS

In 3019 population-based participants (51.9% men, 60.1 ± 8.2 years, 27.7% type 2 diabetes [T2D], oversampled]), we measured carotid-femoral pulse wave velocity (cfPWV), carotid distensibility coefficient (DC) and carotid Young's elastic modulus (YEM), and plasma concentrations of factors D and C3. We conducted multiple linear regression to investigate the association of factors D and C3 (main independent variables, standardized) with cfPWV (primary outcome) and DC and YEM (secondary outcomes), adjusted for potential confounders.

RESULTS

Per SD higher factors D and C3, cfPWV was 0.41 m/s [95% confidence interval: 0.34; 0.49] and 0.33 m/s [0.25; 0.41] greater, respectively. These associations were substantially attenuated when adjusted for age, sex, education, mean arterial pressure, and heart rate (0.08 m/s [0.02; 0.15] and 0.11 m/s [0.05; 0.18], respectively), and were not significant when additionally adjusted for T2D, waist circumference and additional cardiovascular risk factors (0.06 m/s [-0.01; 0.13] and 0.01 m/s [-0.06; 0.09], respectively). Results were comparable for carotid YEM and DC. In persons with T2D, but not in those without, the association between factors D and cfPWV was significant in the fully adjusted model (0.14 m/s, [0.01; 0.27], P  = 0.038, Pinteraction  < 0.05).

CONCLUSION

The strong association of plasma factors D and C3 with arterial stiffness in this population-based cohort was not independent of T2D and other metabolic risk factors. Our data suggest that a possible causal pathway starting from alternative complement activation may via hypertension and T2D contribute to greater arterial stiffness.

Differential Roles of Life-Course Cumulative Burden of Cardiovascular Risk Factors in Arterial Stiffness and Thickness

BACKGROUND

Data are limited regarding differential and common effects of cardiovascular risk factors on subclinical changes in vascular structure and function. We aimed to examine the relationships of life-course cumulative burdens of cardiovascular risk factors with adult arterial pulse wave velocity (PWV) and carotid intima-media thickness (CIMT) in a longitudinal cohort of the Bogalusa Heart Study.

METHODS

The cohort consisted of 900 subjects who had aortic-femoral PWV and CIMT measurements. These participants were examined 5-16 times for body mass index (BMI), blood pressure, atherogenic index of plasma (AIP), and low-density lipoprotein cholesterol (LDLC) from childhood to adulthood. The area under the curve (AUC) was calculated as a measure of long-term burden of the risk factors.

RESULTS

Adjusting for covariates, adult PWV was associated with AUCs of BMI, systolic blood pressure (SBP) and AIP (standardized regression coefficient [β] = 0.191, 0.321, 0.153, respectively; P < 0.001 for all). Adult CIMT was associated with AUCs of BMI, SBP, AIP and LDLC (β = 0.115, 0.202, 0.141, 0.152, respectively; P < 0.001 for all). Moreover, childhood BMI was associated with adult PWV and CIMT (β = 0.088 and 0.075, respectively; false discovery rate q values < 0.05 for both), and childhood LDLC with adult CIMT (β = 0.079; false discovery rate q value < 0.05). These associations did not differ significantly among race and sex groups.

CONCLUSIONS

The life-course cumulative burden of BMI, SBP, and AIP has common effects on arterial wall stiffening and thickening, whereas LDLC is specifically associated with arterial wall thickness, and this effect starts in early life.

Arterial Stiffness, Biomarkers of Liver Fat, and the Development of Metabolic Dysfunction in Metabolically Healthy Population: A Prospective Study

Background

Metabolic dysfunction is known to be associated with arterial stiffness. However, the risks of metabolic syndrome and diabetes due to arterial stiffness and the potential mechanism remain unclear. We aimed to investigate the association of arterial stiffness with the risk of metabolic syndrome and diabetes, and determine whether this association is mediated by liver fat.

Methods

A prospective study was conducted with 4,139 Chinese adults who were metabolically healthy at baseline. Arterial stiffness was measured by brachial-ankle pulse wave velocity (baPWV). Obesity was defined as body mass index ≥25 kg/m2. The primary outcomes were incident metabolic syndrome and diabetes.

Results

During a median follow-up of 4.4 years, 1,022 (24.7%) and 354 (9.5%) participants developed metabolic syndrome and diabetes, respectively. Compared with those in the lowest quartile of baPWV, participants in the highest quartile had 85 and 91% higher risks of metabolic syndrome and diabetes [risk ratio (RR) 1.85, 95% confidence interval (CI) 1.41, 2.42 for metabolic syndrome; RR 1.91, 95% CI 1.16, 3.15 for diabetes]. Mediation analyses indicated that fatty liver significantly mediated the association of arterial stiffness with metabolic syndrome and diabetes risk. Specifically, 18.4% of metabolic syndrome and 12.6% of diabetes risk due to arterial stiffness were mediated through fatty liver.

Conclusions

Arterial stiffness was associated with higher risks of metabolic syndrome and diabetes in individuals with obesity. This association may be partially mediated by fatty liver.

Acute Effects of Low-Intensity Electrical Stimulation on Segmental Arterial Stiffness

Electrical muscle stimulation (EMS) has traditionally been employed to improve muscle strength and glucose uptake. EMS may also reduce arterial stiffness, but little is known about whether low-intensity EMS reduces systemic and/or regional arterial stiffness. This study aimed to examine the effects of low-intensity EMS of the lower limbs on segmental arterial stiffness. Fourteen healthy subjects participated in experiments under two different protocols (control resting trial (CT) and electrical stimulation trial (ET)) in random order on separate days. The EMS was applied to the lower limbs at 4 Hz for 20 min at an intensity corresponding to an elevation of approximately 15 beats/min in pulse rate (10.7 ± 4.7% of heart rate reserve). Arterial stiffness was assessed by cardio-ankle vascular index (CAVI), CAVI₀, heart-ankle pulse wave velocity (haPWV), brachial-ankle pulse wave velocity (baPWV), heart-brachial pulse wave velocity (hbPWV), and carotid-femoral pulse wave velocity (cfPWV). In both trials, each parameter was measured at before (Pre) and 5 min (Post 1) and 30 min (Post 2) after trial. After the experiment, CT did not cause significant changes in any arterial stiffness parameters, whereas ET significantly reduced CAVI (from Pre to Post 1: −0.8 ± 0.5 unit p < 0.01), CAVI₀ (from Pre to Post 1: −1.2 ± 0.8 unit p < 0.01), haPWV (from Pre to Post 1: −47 ± 35 cm/s p < 0.01), and baPWV (from Pre to Post 1: −120 ± 63 cm/s p < 0.01), but not hbPWV or cfPWV. Arm diastolic blood pressure (BP) at Post 2 was slightly but significantly increased in the CT compared to Pre or Post 1, but not in the ET. Conversely, ankle diastolic and mean BPs at Post 1 were significantly reduced compared to Pre and Post 2 in the ET (p < 0.01). These findings suggest that low-intensity EMS of the lower limbs reduces arterial stiffness, but only in sites that received EMS.

A novel operator-independent noninvasive device for assessing arterial reactivity

Background

Endothelial dysfunction is associated with increased risk of cardiovascular disease (CVD). Currently available noninvasive methods of measuring endothelial function have limitations. We tested a novel device that provides an automated measurement of the difference between baseline and post-ischemic, hyperemia-induced, brachial arterial compliance, a phenomenon known to be endothelium-dependent. The association between the calculated index, Flow-mediated Compliance Response (FCR), and established CVD risk indices was determined.

Methods

Adults with CVD risk factors or known coronary artery disease (CAD) were enrolled. Framingham Risk Score (FRS) was calculated and presence of metabolic syndrome (MetSyn) was assessed. Carotid artery plaques were identified by ultrasound. Cardiorespiratory fitness was assessed by 6-minute walk test (6MWT). FCR was measured using the device.

Results

Among 135 participants, mean age 49.3 +/- 17.9 years, characteristics included: 48% female, 7% smokers, 7% CAD, 10% type 2 diabetes, 34% MetSyn, and 38% with carotid plaque. Those with MetSyn had 24% lower FCR than those without (p < 0.001). Lower FCR was associated with higher FRS percentile (r = -0.29, p < 0.001), more MetSyn factors (r = -0.30, p < 0.001), more carotid plaques (r = -0.22, p = 0.01), and lower 6MWT (r = 0.34, p < 0.0001).

Conclusion

FCR, an index of arterial reactivity obtained automatically using a novel, operator-independent device, was inversely associated with established CVD risk indices, increased number of carotid plaques, and lower cardiorespiratory fitness. Whether measuring FCR could play a role in screening for CVD risk and assessing whether endothelial function changes in response to treatments aimed at CVD risk reduction, warrants further study.

Arterial Stiffness, Genetic Risk, and Type 2 Diabetes: A Prospective Cohort Study

OBJECTIVE

We aimed to investigate prospective associations of pulse wave arterial stiffness index (ASI) and pulse pressure (PP) with type 2 diabetes (T2D) and assess the modifying effect of genetics.

RESEARCH DESIGN AND METHODS

We included 152,611 participants free of diabetes and cardiovascular disease in the UK Biobank. All participants had ASI and blood pressure measurements collected at baseline visit. In total, 37 single nucleotide polymorphisms were used to calculate the genetic risk score (GRS) of T2D.

RESULTS

During a median follow-up of 9.5 years, 3,000 participants developed T2D. Per-SD increase in ASI was associated with a 3% higher T2D risk (95% CI 2-4%). The hazard ratio (HR) (95% CI) of T2D was 1.58 (1.39-1.80) in the highest quintile group compared with the lowest quintile group of ASI. However, the association between PP and T2D was nonlinear. Compared with the lowest quintile group, the risk of T2D in higher quintile groups of PP was 0.91 (0.79-1.04), 0.98 (0.86-1.11), 1.15 (1.01-1.30), and 1.24 (1.10-1.41), respectively. Furthermore, we observed an interaction between ASI and genetic susceptibility to T2D, because the elevated HR of T2D associated with high ASI was more evident among participants with higher GRS of T2D (P interaction = 0.008), whereas the interaction between PP and GRS was nonsignificant (P interaction = 0.55).

CONCLUSIONS

ASI was associated with an elevated risk of T2D in a dose-response fashion, whereas PP and T2D showed a nonlinear J-shaped association. Additionally, the association between ASI and T2D was partially strengthened by higher genetic susceptibility to T2D.

Structured pain-free exercise progressively improves ankle-brachial index and walking ability in patients with claudication and compressible arteries: an observational study

In patients with peripheral artery disease (PAD), supervised exercise at near-moderate pain improves walking ability but not ankle-brachial index (ABI) values. In a retrospective observational study, we determined vascular and functional effects of a 6-month structured pain-free exercise program in patients with claudication and compressible vessels. Four-hundred and fifty-nine consecutive patients were studied. Segmental limb pressures were measured and ABI calculated during circa-monthly hospital visits. The 6-min (6MWD) and the pain-free walking distance (PFWD) during the 6-min walking test were determined. Two daily 8-min sessions of slow-moderate in-home walking at increasing metronome-paced speed were prescribed. After excluding patients with unmeasurable ABI or incompletion of the program, 239 patients were studied. Safe and satisfactory (88%) execution of the prescribed training sessions was reported. During the visits, bilateral ABI improved (+ 0.07; p < 0.001) as well as the segmental pressures in the more impaired limb, with changes already significant after 5 weeks of slow walking. Both systolic and diastolic blood pressure decreased overtime (F = 46.52; p < 0.001; F = 5.52; p < 0.001, respectively). 6MWD and PFWD improved (41[0‒73]m p < 0.001 and 107[42‒190]m p < 0.001, respectively) with associated decrease of walking heart rate (F = 15.91; p < 0.001) and Physiological Cost Index (F = 235.93; p < 0.001). The variations of most parameters at different visits correlated to the training load calculated. In a regression model, the PFWD variations directly correlated with rate sessions completed, training load and ABI change and inversely with the baseline value (R² = 0.27; p < 0.001). In the PAD population studied, moderate pain-free exercise improved ABI with associated progressive functional and cardiovascular changes occurring regardless of subjects characteristics.

Vascular smooth muscle stiffness and its role in aging

Vascular smooth muscle cells (VSMC) are now considered important contributors to the pathophysiological and biophysical mechanisms underlying arterial stiffening in aging. Here, we review mechanisms whereby VSMC stiffening alters vascular function and contributes to the changes in vascular stiffening observed in aging and cardiovascular disease. Vascular stiffening in arterial aging was historically associated with changes in the extracellular matrix; however, new evidence suggests that endothelial and vascular smooth muscle cell stiffness also contribute to overall blood vessel stiffness. Furthermore, VSMC play an integral role in regulating matrix deposition and vessel wall contractility via interaction between the actomyosin contractile unit and adhesion structures that anchor the cell within the extracellular matrix. Aged-induce phenotypic modulation of VSMC from a contractile to a synthetic phenotype is associated with decreased cellular contractility and increased cell stiffness. Aged VSMC also display reduced mechanosensitivity and adaptation to mechanical signals from their microenvironment due to impaired intracellular signaling. Finally, evidence for decreased contractility in arteries from aged animals demonstrate that changes at the cellular level result in decreased functional properties at the tissue level.

A Primer on Repeated Sitting Exposure and the Cardiovascular System: Considerations for Study Design, Analysis, Interpretation, and Translation

Sedentary behavior, particularly sitting, is ubiquitous in many contemporary societies. This is a major societal concern considering the evidence for a strong association between sitting behavior and cardiovascular disease morbidity and mortality. Unsurprisingly, leading public health agencies have begun to advocate “reduction” in sitting behavior. Though, the guidelines are typically vague and non-specific. The lack of specific guidelines for prolonged sitting is attributable to the absence of available evidence to facilitate guideline development. To inform policy, well-designed randomized controlled trials are required to test the efficacy of specific and translatable sitting reduction strategies. To guide the design of randomized controlled trials, this review postulates that several gaps in the literature first need to be filled. Following a general discussion of the importance of sitting behavior to contemporary societies, each of the following are discussed: (i) acute sitting exposure and systems physiology; (ii) recommendations for a systems physiology toolbox; (iii) study design considerations for acute sitting exposure; and (iv) translation of sitting-focused research.

Volume Elastic Modulus, Vascular Function, and Vascular Structure in Patients with Cardiovascular Risk Factors

Aims: Volume elastic modulus (V _E ), an index of arterial elasticity, and arterial diameter of the brachial artery can be automatically measured by a newly developed oscillometric device. We investigated the associations of V _E with flow-mediated vasodilation (FMD), an index of endothelium-dependent vasodilation, nitroglycerine-induced vasodilation (NID), an index of endothelium-independent vasodilation, and intima-media thickness (IMT) of the brachial artery and association of oscillometrically measured brachial artery diameter with ultrasonographically measured brachial artery diameter in patients with cardiovascular risk factors.

Methods: Oscillometric measurements of V _E and brachial artery diameter and ultrasound measurements of brachial artery diameter, FMD, NID, and IMT of the brachial artery were performed in 50 patients with cardiovascular risk factors.

Results: The mean values were 2.1±0.4 mmHg/% for V _E , 0.31±0.05 mm for brachial IMT, 4.48±0.70 mm for oscillometric brachial artery diameter, and 4.30±0.55 mm for ultrasound brachial artery diameter. V _E significantly correlated with brachial IMT (r=0.51, P ＜0.001), whereas there was no significant correlation of V _E with FMD (r=-0.08, P =0.58) or NID (r=0.07, P =0.61). Multivariate analysis revealed that V _E was significantly associated with brachial IMT (β=0.33, P =0.04). Oscillometric brachial artery diameter significantly correlated with ultrasound brachial artery diameter (r=0.79, P ＜0.001). The Bland-Altman plot showed good agreement between oscillometric brachial artery diameter and ultrasound brachial artery diameter (mean difference, -0.17 mm; limits of agreement, -1.03 mm to 0.69 mm).

Conclusions: In patients with cardiovascular risk factors, V _E may represent atherosclerotic structural alterations of the vascular wall but not vascular function. The accuracy of oscillometric measurement of brachial artery diameter is acceptable.

Assessment of vascular function in complete glycaemic spectrum

Purpose: The present study was conceived to delineate the point of vascular dysfunction along the glycemic spectrum (normoglycemic individuals with no family history of diabetes, normoglycemic individuals with family history of diabetes, prediabetic individuals, and diabetic individuals).Materials and Methods: In this cross-sectional comparative study, we enrolled 252 participants of both gender in the age group of 30-50 years. They were classified based on their family history of diabetes and glycemic status into four groups along the glycemic spectrum as mentioned above. We measured flow-mediated dilation (FMD) from brachial artery and vascular function biomarkers such as enthothelin-1 (ET-1), von Willbrand Factor (vWF), Vascular Endothelial Growth Factor (VEGF) to assess the vascular function. The comparison of data between groups were done using One Way ANOVA/Kruskal-Wallis followed by post-hoc analysis using LSD/Mann-Whitney U Test depending on the normality of the data. Spearman correlation was done between vascular function and plasma glucose levels to identify its relationship. Linear regression was carried out to identify the factors influencing the FMD across the glycemic spectrum.Results: We observed that vascular function negatively correlated with blood glucose levels. However, endothelin-1 and vWF derangement was there even in normoglycemic first degree relatives of diabetes (FDRD) and the derangement increased in prediabetes and diabetes. Physiological dysfunction in terms of decreased flow-mediated dilation starts from prediabetes only. VEGF derangement is found only in diabetic individuals.Conclusion: Vascular dysfunction is found even in normoglycemic FDRD and the derangement increased and compounded with the advancement of disease.

Arterial stiffness is not acutely modified by consumption of a caffeinated soft drink sweetened with high-fructose corn syrup in young healthy adults

We tested the hypothesis that ingestion of a caffeinated soft drink sweetened with high‐fructose corn syrup acutely increases arterial stiffness. In a randomized counterbalanced, crossover design, fourteen healthy adults (25 ± 3 years, 6 women) reported to the laboratory for two experimental visits where 500 ml of tap water (H₂O) or 500 ml of Mountain Dew® (a caffeinated soft drink sweetened with high‐fructose corn syrup (HFCS)) were consumed. Arterial stiffness (carotid‐to‐femoral pulse wave velocity (cfPWV)), peripheral and central blood pressures were measured pre‐consumption, 30 min post‐consumption, and 120 min post‐consumption. Prior to each measurement period, beat‐to‐beat hemodynamic measures were collected. Changes in heart rate, blood pressure, and cardiac output from pre‐consumption did not differ between trials at any timepoint (p ≥ 0.06). Moreover, changes in peripheral or central blood pressures from pre‐consumption did not differ between trials (p ≥ 0.84). Likewise, changes in cfPWV from pre‐consumption to 30 min post‐consumption (HFCS: 0.2 ± 0.3 m/s, H₂O: 0.0 ± 0.3 m/s, p = 0.34) and 120 min post‐consumption (HFCS: 0.3 ± 0.4 m/s, H₂O: 0.2 ± 0.3 m/s, p = 0.77) did not differ. Changes in aortic augmentation pressure, augmentation index, augmentation index corrected to a heart rate of 75 bpm, and reflection magnitude did not differ between conditions at 30 min post‐ (p ≥ 0.55) or 120 min post‐ (p ≥ 0.18) consumption. In healthy young adults, ingesting 500 ml of a commercially available caffeinated soft drink sweetened with high‐fructose corn syrup does not acutely change indices of arterial stiffness and wave reflection.

Flow-mediated dilation analysis coupled with nitric oxide transport to enhance the assessment of endothelial function

Flow-mediated dilation (FMD), mainly mediated by nitric oxide (NO), aims to assess the shear-induced endothelial function, which is widely quantified by the relative change in arterial diameter after dilation (FMD%). However, FMD% is affected by individual differences in blood pressure, blood flow, and arterial diameter. To reduce these differences and enhance the assessment of FMD to endothelial function, we continuously measured not only the brachial artery diameter and blood flow with ultrasound but also blood pressure with noninvasive monitor during standard FMD test. We further constructed an analytical model of FMD coupled with NO transport, blood flow, and arterial deformation. Combining the time-averaged and peak values of arterial diameter, blood flow, and pressure, and the modeling, we assumed the artery was completely healthy and calculated an ideally expected FMD% (eFMD%). Then, we expressed the fractional flow-mediated dilation (FFMD%) for the ratio of measured FMD% (mFMD%) to eFMD%. Furthermore, using the continuous waveforms of arterial diameter, blood flow, and pressure, the endothelial characteristic parameter (ϵ) was calculated, which describes the function of the endothelium to produce NO and ranges from 1 to 0 representing the endothelial function from healthiness to complete loss. We found that the mFMD% and eFMD% between the young age (n = 5, 21.2 ± 1.8 yr) and middle age group (n = 5, 34.0 ± 2.1 yr) have no significant difference (P = 0.222, P = 0.385). In contrast, the FFMD% (P = 0.008) and ϵ (P = 0.007) both show significant differences. Therefore, the fractional flow-mediated dilation (FFMD%) and the endothelial characteristic parameter (ϵ) may have the potential for specifically diagnosing the endothelial function.NEW & NOTEWORTHY FMD% is affected by various factors, which limits its ability to assess the endothelial function. We developed an analytical model of FMD process coupled with nitric oxide based on the mathematical modeling and physiological measurements. Two model-derived indicators (FFMD% and ϵ) were introduced based on the modeling. Our results indicated that FFMD% and ϵ may have the potential to distinguish the endothelial function between the young- and middle age groups.

Acute Effects of Short-Term Warm Water Immersion on Arterial Stiffness and Central Hemodynamics

Warm water immersion (WWI) has a potentially favorable effect on vascular health. However, the effects of short-term WWI on vascular function and central hemodynamics remain unclear. The present study aimed to determine the acute effects of short-term WWI on arterial stiffness and central hemodynamics in healthy men. Ten healthy men (27–57 years, 44 ± 12 years of mean age) underwent 5-min WWI (40–41°C) at the heart level. Systemic hemodynamics and tympanic temperature were monitored during WWI. Furthermore, pulse wave velocity (PWV) and aortic hemodynamics were measured before and 10 min after WWI. Cardiac output (CO) (via the Modelflow method) increased (P = 0.037), whereas tympanic temperature did not change (P = 0.879) during WWI. After 5-min WWI, heart rate (HR) and brachial diastolic blood pressure (BP) were significantly decreased. Aortic and leg PWV were decreased by 7.5 and 3.1%, respectively (P = 0.006 and P = 0.040). Femoral arterial blood flow was increased by 45.9% (P = 0.002), and leg vascular resistance was decreased by 29.1% (P < 0.001). Regarding central hemodynamic variables (estimated by general transfer function), aortic BP and augmentation index (AIx) did not change significantly, but the subendocardial viability ratio (SEVR), an index of coronary perfusion, was increased (P = 0.049). Our results indicate that a short-term WWI acutely improves aortic and peripheral arterial stiffness and coronary perfusion. Further studies to determine the interaction between the residual effect of a single bout of short-term WWI and chronic change (e.g., adaptation) in arterial stiffness and central hemodynamics are needed.

Increase in arterial stiffness measures after bariatric surgery

BACKGROUND AND AIMS

The relationship between obesity and arterial stiffness is complex, with a potential interaction by age (inverse association at younger age and positive at older age) and conflicting reports on the effect of lifestyle-based weight loss on arterial stiffness. Little is understood about post-bariatric surgery changes in arterial stiffness. This study aimed to examine post-bariatric surgery changes in arterial stiffness and identify factors associated with greater changes in arterial stiffness.

METHODS

In 72 patients (mean age 44.5 years, 72.2% female), we evaluated two arterial stiffness measures, cardio-ankle vascular index (CAVI) and heart-ankle pulse wave velocity (haPWV), one month prior to and 6 months after bariatric surgery. Another follow-up visit was conducted 12 months after bariatric surgery in a subset of 58 participants.

RESULTS

Six months after bariatric surgery, an evident decrease was seen in body mass index, heart rate, and systolic blood pressure. In contrast, both CAVI and haPWV significantly increased at 6 months (+0.64 [0.42, 0.87] and +0.24 [0.04, 0.44] m/s, respectively). Among 58 patients with relevant data, CAVI and haPWV remained elevated 12 months after bariatric surgery (+0.80 [0.53, 1.07] and +0.40 [0.17, 0.62] m/s, respectively). Being non-diabetic and having larger decreases in post-surgery heart rate were independently associated with greater increases in post-surgical CAVI.

CONCLUSIONS

Arterial stiffness measures, CAVI and haPWV, were elevated after bariatric surgery despite other favorable cardiometabolic changes. Further studies are necessary to elucidate the underlying mechanism and prognostic implications of this elevation in arterial stiffness measures after bariatric surgery.

THE EFFECTS OF BASKETBALL AND SOCCER TRAINING ON ARTERIAL STIFFNESS

ABSTRACT Objective The purpose of this study was to examine arterial stiffness in elite basketball and soccer athletes by pulse wave velocity. Methods The cohort comprised 35 healthy male volunteers aged 17 to 26 years. All the subjects were either basketball players (n=9), soccer players (n=12) or sedentary controls (n=14). Arterial stiffness was measured by the Pulse Trace System (Micro Medical Ltd., Rochester, UK) and echocardiographic images were taken using a commercially available machine (Vivid 7 GE-Vingmed, Horten, Norway) with a 2.5 MHz transducer. Results The basketball players had significantly higher heights and body weights as compared to both the soccer players and the controls. The aortic elastic properties derived from the echocardiographic measurements did not differ between the groups. The peripheral pulse wave velocity measurements showed significantly lower values both in the basketball and soccer players compared to the controls, whereas the central pulse wave velocity measurement was significantly lower only in the basketball players as compared to the controls. No significant difference was seen between the basketball and soccer players. Conclusions The results of this study show that football and basketball exercises comprised of aerobic, anaerobic, endurance balance-coordination and sport-specific training play a role in reducing arterial stiffness. Level of evidence I; type of study: prognostic study.

Variability of peripheral pulse wave velocity in patients with diabetes mellitus type 2 during orthostatic challenge

Diabetes mellitus 2 (DM2) is the seventh cause of death worldwide. One of the reasons is late diagnosis of vascular damage. Pulse wave velocity (PWV) has become an independent marker of arterial stiffness and cardiovascular risk. Moreover, the previous studies have shown the importance of beat-to-beat PWV measurement due to its variability among the heart cycle. However, variability of PWV (PWVv) of the whole body hasn't been examined yet. We have studied a group of DM II and heathy volunteers, to investigate the beat-to-beat mean PWV (PWVm) and PWVv in the different body positions. PWV of left lower and upper extremities were measured in DM2 (7 m/8 f, age 68+/-10 years, BP 158/90+/-19/9 mm Hg) and healthy controls (5 m/6 f, age 23+/-2 years, BP 117/76+/-9/5 mm Hg). Volunteers were lying in the resting position and of head-up-tilt in 45° (HUT) for 6 min. PWVv was evaluated as a mean power spectrum in the frequency bands LF and HF (0.04-0.15 Hz, 0.15-0.5 Hz). Resting PWVm of upper extremity was higher in DM2. HUT increased lower extremity PWVm only in DM2. Extremities PWVm ratio was significantly lower in DM2 during HUT compared to controls. LF and HF PWVv had the same response to HUT. Resting PWVv was higher in DM2. Lower extremity PWVv increased during HUT in both groups. PWVm and PWVv in DM2 differed between extremities and were significantly influenced by postural changes due to hydrostatic pressure. Increased resting PWVm and PWVv in DM2 is a marker of increased arterial stiffness.

Impact of whole body passive heat stress and arterial shear rate modification on radial artery function in young men

We sought to determine how whole body heating acutely influences radial artery function, characterized using flow-mediated dilation (FMD) and low-flow-mediated constriction (L-FMC), and the mechanistic role of shear rate modification on radial artery functional characteristics during heating. Eleven young healthy men underwent whole body heating (water-perfused suit) sufficient to raise the core temperature by +1°C. Trials were repeated with (heat + WC) and without (heat) the application of a wrist cuff located distal to the radial artery examined, known to prevent increases in mean and anterograde shear rates but increase retrograde shear rate. Radial artery characteristics were assessed throughout each trial, with FMD and L-FMC assessed before and upon reaching the target core temperature. Heat markedly increased radial artery mean and anterograde shear rates, along with radial artery diameter and blood flow (P < 0.05). Heat + WC abolished the heat-induced increase in mean and anterograde shear rates (P > 0.05) but markedly increased retrograde shear rate (P < 0.05). Concomitantly, increases in radial artery diameter and blood flow were decreased (heat + WC vs. heat, P < 0.05). Heat attenuated FMD (8.6 ± 1.2% vs. 2.2 ± 1.4%, P < 0.05), whereas no change in FMD was observed in heat + WC (7.8 ± 1.2% vs. 10.8 ± 1.2%, P > 0.05). In contrast, L-FMC was not different in either trial (P > 0.05). In summary, acute whole body heating markedly elevates radial artery shear rate, diameter, and blood flow and diminishes FMD. However, marked radial artery vasodilation and diminished FMD are absent when these shear rate changes are prevented. Shear rate modifications underpin the radial artery response to acute whole body heat stress, but further endothelium-dependent vasodilation (FMD) is attenuated likely as the vasodilatory range limit is approached.NEW & NOTEWORTHY We observed that acute whole body heating elevates radial artery shear rate, diameter, and blood flow. This results in a diminished flow-meditated dilatation (FMD) but does not change low-flow-mediated constriction (L-FMC). Preventing shear rate changes during whole body heating reduces radial artery vasodilation and reverses FMD reductions but has no effect on L-FMC. These findings indicate that shear rate changes underpin conduit artery responses to acute whole body heat stress, but further endothelium-dependent flow-mediated vasodilation is attenuated as the vasodilatory range limit is approached.

Noninvasive Measurement of Time-Varying Arterial Wall Elastance Using a Single-Frequency Vibration Approach

The arterial wall elastance is an important indicator of arterial stiffness and a kind of manifestation associated with vessel-related disease. The time-varying arterial wall elastances can be measured using a multiple-frequency vibration approach according to the Voigt and Maxwell model. However, such a method needs extensive calculation time and its operating steps are very complex. Thus, the aim of this study is to propose a simple and easy method for assessing the time-varying arterial wall elastances with the single-frequency vibration approach. This method was developed according to the simplified Voigt and Maxwell model. Thus, the arterial wall elastance measured using this method was compared with the elastance measured using the multiple-frequency vibration approach. In the single-frequency vibration approach, a moving probe of a vibrator was induced with a radial displacement of 0.15 mm and a 40 Hz frequency. The tip of the probe directly contacted the wall of a superficial radial artery, resulting in the arterial wall moving 0.15 mm radially. A force sensor attached to the probe was used to detect the reactive force exerted by the radial arterial wall. According to Voigt and Maxwell model, the wall elastance (E_single) was calculated from the ratio of the measured reactive force to the peak deflection of the displacement. The wall elastances (E_multiple) measured by the multiple-frequency vibration approach were used as the reference to validate the performance of the single-frequency approach. Twenty-eight healthy subjects were recruited in the study. Individual wall elastances of the radial artery were determined with the multiple-frequency and the single-frequency approaches at room temperature (25 °C), after 5 min of cold stress (4 °C), and after 5 min of hot stress (42 °C). We found that the time-varying E_single curves were very close to the time-varying E_multiple curves. Meanwhile, there was a regression line (E_single = 0.019 + 0.91 E_multiple, standard error of the estimate (SEE) = 0.0295, p < 0.0001) with a high correlation coefficient (0.995) between E_single and E_multiple. Furthermore, from the Bland-Altman plot, good precision and agreement between the two approaches were demonstrated. In summary, the proposed approach with a single-frequency vibrator and a force sensor showed its feasibility for measuring time-varying wall elastances.

Acute effect of passive one-legged intermittent static stretching on regional blood flow in young men

PURPOSE

Passive stretching reduces stiffness in the lower limb arteries of the stretched limb. To address this physiological mechanism, we measured the change in shear rate in the posterior tibial artery during a single bout of one-legged passive calf stretching compared with that in the non-stretched leg.

METHODS

The diameter, mean blood velocity, blood flow, and shear rate in the posterior tibial artery were measured using Doppler ultrasound before (baseline), during, and after a one-legged passive intermittent calf stretching procedure (six repetitions of 30-s static stretch with 10-s relaxation) in nine healthy young men.

RESULTS

In the posterior tibial artery of the stretched leg, the arterial diameter significantly decreased from baseline during the stretching period (baseline vs. stretching period of the 6th set, 0.19 ± 0.01 vs. 0.18 ± 0.01 cm, P < 0.05) without any change in shear rate and mean blood velocity. In contrast, during the relaxation period, the mean blood velocity (baseline vs. relaxation period of the 5th set, 2.98 ± 0.54 vs. 6.25 ± 1.48 cm/s) increased, and consequently, the shear rate (baseline vs. relaxation period of the 5th set, 66.75 ± 15.39 vs. 122.85 ± 29.40 s^-1) increased (each P < 0.01); however, there was no change in arterial diameter. In contrast, these values in the non-stretched leg were unchanged at all-time points.

CONCLUSIONS

The stretching procedure increased the shear rate in the peripheral artery of the stretched leg during the relaxation period. This finding indicates that the local hemodynamic response (possibly through endothelial function), resulting from an increase in shear stress, may contribute to stretching-induced attenuation of local arterial stiffness.

Endothelium function dependence of acute changes in pulse wave velocity and flow-mediated slowing

Flow-mediated slowing (FMS), defined as the minimum pulse wave velocity (PWVmin) during reactive hyperemia, is potentially a simple, user-objective test for examining endothelial function. The purpose of the current study was to determine the effects of a known endothelial dysfunction protocol on arm PWV and PWVmin. Complete data were successfully collected in 22 out of 23 healthy adults (23.8 years [SD 4.1], 16 F, 22.8 kg/m2 [SD 2.8]). Local endothelial dysfunction was induced by increasing retrograde shear stress in the upper arm, through inflation of a distal (forearm) tourniquet to 75 mmHg, for 30 min. Pre- and post-endothelial dysfunction, PWV was measured followed by simultaneous assessment of PWVmin and flow-mediated dilation (FMD). PWV was measured between the upper arm and wrist using an oscillometric device, and brachial FMD using ultrasound. FMD (%) and PWVmin (m/s) were calculated as the maximum increase in diameter and minimum PWV during reactive hyperemia, respectively. Endothelial dysfunction resulted in a large effect size (ES) decrease in FMD (∆ = -3.10%; 95% CI: -4.15, -2.05; ES = -1.3), and a moderate increase in PWV (∆ = 0.38 m/s; 95% CI: 0.07, 0.69; ES = 0.5) and PWVmin (∆ = 0.16 m/s; 95% CI: 0.05, 0.28; ES = 0.6). There was a large intra-individual (pre- vs post-endothelial dysfunction) association between FMD and PWVmin (r = -0.61; 95% CI: -0.82, -0.24). In conclusion, acute change in PWV and PWVmin are at least partially driven by changes in endothelial function.

Potential of Chlorella as a Dietary Supplement to Promote Human Health

Chlorella is a green unicellular alga that is commercially produced and distributed worldwide as a dietary supplement. Chlorella products contain numerous nutrients and vitamins, including D and B12, that are absent in plant-derived food sources. Chlorella contains larger amounts of folate and iron than other plant-derived foods. Chlorella supplementation to mammals, including humans, has been reported to exhibit various pharmacological activities, including immunomodulatory, antioxidant, antidiabetic, antihypertensive, and antihyperlipidemic activities. Meta-analysis on the effects of Chlorella supplementation on cardiovascular risk factors have suggested that it improves total cholesterol levels, low-density lipoprotein cholesterol levels, systolic blood pressure, diastolic blood pressure, and fasting blood glucose levels but not triglycerides and high-density lipoprotein cholesterol levels. These beneficial effects of Chlorella might be due to synergism between multiple nutrient and antioxidant compounds. However, information regarding the bioactive compounds in Chlorella is limited.

Effects of Inhibition of Nitric Oxide Synthase on Muscular Arteries During Exercise: Nitric Oxide Does Not Contribute to Vasodilation During Exercise or in Recovery

Background

Basal release of nitric oxide (NO) from the vascular endothelium regulates the tone of muscular arteries and resistance vasculature. Effects of NO on muscular arteries could be particularly important during exercise when shear stress may stimulate increased NO synthesis.

Methods and Results

We investigated acute effects of NO synthase inhibition on exercise hemodynamics using N^G‐monomethyl‐l‐arginine (l‐NMMA), a nonselective NO synthase ‐inhibitor. Healthy volunteers (n=10, 5 female, 19–33 years) participated in a 2‐phase randomized crossover study, receiving l‐NMMA (6 mg/kg, iv over 5 minutes) or placebo before bicycle exercise (25–150 W for 12 minutes). Blood pressure, cardiac output (measured by dilution of soluble and inert tracers) and femoral artery diameter were measured before, during, and after exercise. At rest, l‐NMMA reduced heart rate (by 16.2±4.3 bpm relative to placebo, P<0.01), increased peripheral vascular resistance (by 7.0±1.4 mmHg per L/min, P<0.001), mean arterial blood pressure (by 8.9±3.5 mmHg, P<0.05), and blunted an increase in femoral artery diameter that occurred immediately before exercise (change in diameter: 0.14±0.04 versus 0.32±0.06 mm after l‐NMMA and placebo, P<0.01). During/after exercise l‐NMMA had no significant effect on peripheral resistance, cardiac output, or on femoral artery diameter.

Conclusions

These results suggest that NO plays little role in modulating muscular artery function during exercise but that it may mediate changes in muscular artery tone immediately before exercise.

Can vasohibin-1, an endothelium-derived angiogenesis inhibitor, be a marker of endothelial dysfunction in hemodialysis patients?

BACKGROUND

Endothelial dysfunction (ED) is associated with high cardiovascular disease burden in hemodialysis (HD) patients. Vasohibin-1, an endothelium-derived angiogenesis inhibitor, is essential for endothelial cell survival, therefore it may be a promising marker of ED. We aimed to investigate whether vasohibin-1 levels are associated with ED markers in HD patients.

METHODS

Fifty HD patients and 30 healthy controls were included in the study. As markers of ED, endothelium-dependent flow-mediated dilatation (FMD), carotid intima-media thickness (CIMT), and pulse wave velocity (PWV) were examined. Serum vasohibin-1 levels were measured with ELISA.

RESULTS

Serum vasohibin-1 levels were low (387.7 ± 115.7 vs 450.1 ± 140.1 P = .02), FMDs' were impaired (6.65 ± 2.50 vs 10.95 ± 2.86 P < .001), PWV (7.92 ± 1.964 vs 6.79 ± 0.96 P = .01) and CIMT (0.95 ± 0.20 vs 0.60 ± 0.11 P < .001) were increased in HD patients compared to healthy controls. In regression analysis, vasohibin-1 levels were not related with FMD, PWV, or CIMT.

CONCLUSIONS

Hemodialysis patients have low serum vasohibin-1 levels but serum levels of vasohibin-1 did not show any significant relationship with FMD, PWV, and CIMT in HD patients. Since vasohibin-1 acts via paracrine pathways, serum levels may be insufficient to explain the relationship between vasohibin and ED. Local vasohibin-1 activity on tissue level may be more important instead of circulating levels.

Association between brachial-ankle pulse wave velocity and risk of type 2 diabetes mellitus: results from a cohort study

INTRODUCTION

Brachial-ankle pulse wave velocity (ba-PWV), as a simple and easily measured marker of arterial stiffness, has not been prospectively explored for its role in type 2 diabetes mellitus (T2DM) risk among the general population. This study aimed to explore the association between baseline ba-PWV value and new-onset T2DM among Chinese adults.

RESEARCH DESIGN AND METHODS

Using data from Xiaotangshan Hospital, we conducted a prospective cohort study among those who underwent annual or biennial health check-up examinations and who had their ba-PWV measured from 2009 to 2016. We explored the risk of new-onset T2DM across ba-PWV tertiles using Cox proportional-hazards regression analysis.

RESULTS

Of 6122 adults (68.9% male; mean age: 51.0 (SD 13.0) years) without T2DM and with ba-PWV measured at baseline, 599 participants developed T2DM during an average of 3.8 (SD 2.3) years of follow-up. After multivariable adjustment, ba-PWV was positively related to T2DM risk (p for trend=0.008). Compared with the lowest ba-PWV tertile, the HRs and their 95% CIs were 1.57 (1.18 to 2.10) for the second and 1.66 (1.24 to 2.22) for the third tertile. The risk across ba-PWV tertiles increased steadily from 1000 cm/s to 1400 cm/s and then reached a plateau. Subgroup analyses indicated a significantly higher risk among those aged <65 years and current smokers (p for interactions: <0.001 and 0.006).

CONCLUSIONS

Our findings suggest that ba-PWV might be a useful and independent predictor of new-onset T2DM with ba-PWV ranging between 1000 cm/s and 1400 cm/s, especially among younger individuals and current smokers.

Ex vivo aortic stiffness in mice with different eNOS activity

Endothelial function and NO bioavailability are important determinants of aortic biomechanics and function. With a new technique we investigated the ex vivo aortic segment biomechanics of different mouse models with altered NO signaling. Our experiments clearly show that chronic distortion of NO signaling triggered several compensatory mechanisms that reflect the organism’s attempt to maintain optimal central hemodynamics.

Passive leg movement in chronic obstructive pulmonary disease: evidence of locomotor muscle vascular dysfunction

Chronic obstructive pulmonary disease (COPD), characterized by pulmonary dysfunction, is now also recognized to be associated with free radical-mediated vascular dysfunction. However, as previous investigations have utilized the brachial artery flow-mediated dilation technique, whether such vascular dysfunction exists in the locomotor muscle of patients with COPD remains unclear. Therefore, in patients with COPD (n = 13, 66 ± 6 yr) and healthy age- and sex-matched control subjects (n = 12, 68 ± 6 yr), second-by-second measurements of leg blood flow (LBF) (ultrasound Doppler), mean arterial pressure (MAP) (Finapres), and leg vascular conductance (LVC) were recorded before and during both 2 min of continuous upright seated continuous-movement passive leg movement (PLM) and a single-movement PLM (sPLM). In response to PLM, both peak change in LBF (COPD 321 ± 54, Control 470 ± 55 ∆mL/min) and LVC (COPD 3.0 ± 0.5, Control 5.4 ± 0.5 ∆mL·min^-1·mmHg^-1) were significantly attenuated in patients with COPD compared with control subjects (P < 0.05). This attenuation in the patients with COPD was also evident in response to sPLM, with peak change in LBF tending to be lower (COPD 142 ± 26, Control 169 ± 14 ∆mL/min) and LVC being significantly lower (P < 0.05) in the patients than the control subjects (COPD 1.6 ± 0.4, Control 2.5 ± 0.3 ∆mL·min^-1·mmHg^-1). Therefore, utilizing both PLM and sPLM, this study provides evidence of locomotor muscle vascular dysfunction in patients with COPD, perhaps due to redox imbalance and reduced nitric oxide bioavailability, which is in agreement with an increased cardiovascular disease risk in this population. This locomotor muscle vascular dysfunction, in combination with the clearly dysfunctional lungs, may contribute to the exercise intolerance associated with COPD.NEW & NOTEWORTHY Utilizing both the single and continuous passive leg movement (PLM) models, which induce nitric oxide (NO)-dependent hyperemia, this study provides evidence of vascular dysfunction in the locomotor muscle of patients with chronic obstructive pulmonary disease (COPD), independent of central hemodynamics. This impaired hyperemia may be the result of an oxidant-mediated attenuation in NO bioavailability. In addition to clearly dysfunctional lungs, vascular dysfunction in locomotor muscle may contribute to the exercise intolerance associated with COPD and increased cardiovascular disease risk.

Obesity-Induced Hypertension: Heavy on the Accelerator

See Article Fan et al.

Effects of heated water-based versus land-based exercise training on vascular function in individuals with peripheral artery disease

Peripheral artery disease (PAD) is an atherosclerotic disease that is associated with poor vascular function, walking impairment, and reduced quality of life. Land-based exercise therapy (LBET) is frequently recommended to improve walking and reduce symptoms. Recently, evidence has suggested that heated-water exercise therapy (HWET) is an effective intervention for PAD. However, the efficacy of LBET versus HWET in PAD patients had not been elucidated. Therefore, we sought to compare effects of LBET with HWET on cardiovascular function, exercise tolerance, physical function, and body composition in PAD patients. PAD patients (n = 53) were recruited and randomly assigned to a LBET group (n = 25) or HWET group (n = 28). The LBET group performed treadmill walking, whereas the HWET group performed walking in heated water for 12 wk. Leg (legPWV) and brachial-to-ankle arterial stiffness (baPWV), blood pressure (BP), ankle-brachial index (ABI), 6-min walking distance (6MWD), claudication onset time (COT), physical function, and body composition were assessed before and after 12 wk. There were significant group-by-time interactions (P < 0.05) for legPWV, BP, 6MWD, COT, body composition, and resting metabolic rate (RMR). Both groups significantly reduced (P < 0.05) legPWV, BP, and body fat percentage, and HWET measures were significantly lower than LBET measures. Both groups significantly increased 6MWD, COT, and RMR, and HWET group measures were significantly greater than LBET measures. A time effect was noted for baPWV reduction in both groups (P < 0.05). These results suggest that both LBET and HWET improve cardiovascular function, exercise tolerance, and body composition, and HWET showed considerably greater improvements compared with LBET in patients with PAD.NEW & NOTEWORTHY The results of this study reveal for the first time that although land-based exercise therapy is effective for reducing arterial stiffness and blood pressure in patients with peripheral artery disease (PAD), heated-water exercise therapy demonstrates greater benefits on vascular function. The greater improvements in muscular strength, time to onset of claudication, and exercise tolerance after heated-water exercise therapy may have clinical implications for improving quality of life in patients with PAD. The heated-water exercise therapy intervention demonstrated relatively higher exercise training adherence (∼88%) compared with the land-based exercise intervention (∼81%).

The importance of the nitric oxide-cGMP pathway in age-related cardiovascular disease: Focus on phosphodiesterase-1 and soluble guanylate cyclase

Among ageing-related illnesses, cardiovascular disease (CVD) remains the leading cause of morbidity and mortality causing one-third of all deaths worldwide. Ageing evokes a number of functional, pharmacological and morphological changes in the vasculature, accompanied by a progressive failure of protective and homeostatic mechanisms, resulting in target organ damage. Impaired vasomotor, proliferation, migration, antithrombotic and anti-inflammatory function in both the endothelial and vascular smooth muscle cells are parts of the vascular ageing phenotype. The endothelium regulates these functions by the release of a wide variety of active molecules including endothelium-derived relaxing factors such as nitric oxide, prostacyclin (PGI₂ ) and endothelium-derived hyperpolarization (EDH). During ageing, a functional decay of the nitric oxide pathway takes place. Nitric oxide signals to VSMC and other important cell types for vascular homeostasis through the second messenger cyclic guanosine monophosphate (cGMP). Maintenance of proper cGMP levels is an important goal in sustainment of proper vascular function during ageing. For this purpose, different components can be targeted in this signalling system, and among them, phosphodiesterase-1 (PDE1) and soluble guanylate cyclase (sGC) are crucial. This review focuses on the role of PDE1 and sGC in conditions that are relevant for vascular ageing.

Interaction Between Sacubitril and Valsartan in Preventing Heart Failure Induced by Aortic Valve Insufficiency in Rats

BACKGROUND

Synergistic interactions between neprilysin inhibition (NEPi) with sacubitril and angiotensin receptor type1 blockade (ARB) with valsartan have been implicated in improvement of left ventricular (LV) contractility, relaxation, exercise tolerance, and fibrosis in preexisting heart failure (HF) induced by aortic valve insufficiency (AVI). It is not known whether this pharmacologic synergy can prevent cardiovascular pathology in a similar AVI model. Our aim was to investigate the pharmacology of sacubitril/valsartan in an experimental setting with therapy beginning immediately after creation of AVI.

METHODS

HF was induced through partial disruption of the aortic valve in rats. Therapy began 3 hours after valve disruption and lasted 8 weeks. Sacubitril/valsartan (68 mg/kg), valsartan (31 mg/kg), sacubitril (31 mg/kg), or vehicle were administered daily via oral gavage (N=8 in each group). Hemodynamic assessments were conducted using Millar technology, and an exercise tolerance test was conducted using a rodent treadmill.

RESULTS

Only sacubitril/valsartan increased total arterial compliance and ejection fraction (EF). Therapies with sacubitril/valsartan and valsartan similarly improved load-dependent (dP/dt_max) and load independent indices (Ees) of LV contractility, and exercise tolerance, whereas sacubitril did not. None of the therapies improved LV relaxation (dP/dt_min), whereas all reduced myocardial fibrosis.

CONCLUSIONS

1) The synergistic interaction between NEPi and ARB in early therapy with sacubitril/valsartan leads to increased total arterial compliance and EF. 2) Improvement in indices of LV contractility, and exercise tolerance with sacubitril/valsartan is likely because of ARB effect of valsartan. 3) All three therapies provided antifibrotic effects, suggesting both ARB and NEPi are capable of reducing myocardial fibrosis.