Association of pulse wave velocity and intima-media thickness with cardiovascular risk factors in young adults.

Pulse wave velocity (PWV), a measure of arterial stiffness, and intima-media thickening (IMT), a measure of early atherosclerosis, are intermediate markers of cardiovascular disease which are predictive of cardiovascular events. Traditionally, both were thought to result from accumulative exposure to traditional cardiovascular risk factors. However, their association with risk factors in young adults in low-income settings is unknown. We sought to investigate the association between PWV and IMT with traditional cardiovascular risk factors in the Andhra Pradesh Children and Parents Study cohort from Southern India. Male and female adults (N = 1440) aged between 20 and 24 years underwent measures of PWV and IMT. Exposure variables included smoking, body mass index (BMI), mean arterial pressure (MAP), glucose, homeostatic model assessment of insulin resistance (HOMA-IR), total cholesterol, high-density lipoprotein cholesterol (HDL-cholesterol), and triglycerides. Association between outcome and exposure variables was assessed using linear regression analysis. Average values for PWV and IMT were 5.9 ± 0.6 m/s and 0.5 ± 0.1 mm. In univariable analysis, PWV associated with MAP, BMI, smoking, total cholesterol, glucose, and HOMA-IR and IMT associated with MAP, BMI, tobacco use, and HDL-cholesterol. In multivariable analysis, PWV remained strongly positively associated with MAP increasing by 0.5 m/s (P < .001) for a 10 mm Hg increase in MAP (R2  = .37). In contrast, IMT negatively associated with HDL-cholesterol (β = -.10; P = .012, R2  = .02). There was weak evidence that PWV and IMT positively associated with BMI. In young adults from Southern India, PWV positively associated with blood pressure and IMT negatively associated with HDL-cholesterol. This suggests separate etiologies for atherosclerosis and arterial stiffening in young adults

RELATION OF PULSE WAVE VELOCITY TO CONTEMPORANEOUS AND HISTORICAL BLOOD PRESSURE IN FEMALE TWINS:Arterial Stiffness and Blood Pressure

An association between blood pressure and aortic stiffness is well known, but ambiguity remains as to whether one precedes the other. This study aimed to investigate the association of aortic stiffness with contemporaneous versus historic blood pressure and direction of causality between aortic stiffening and hypertension in female twins. METHODS: Aortic stiffness, measured by carotid-femoral pulse wave velocity (PWV), and mean arterial pressure (MAP) was recorded in 2037 female TwinsUK participants (mean age: 62.4±9.7 years) at a single time point. A subset of 947 participants had repeat PWV and MAP measures (mean interval 5.5±1.7 years) with additional historic MAP (mean interval 6.6±3.3 years before baseline). RESULTS: Cross-sectional multivariable linear regression analysis confirmed PWV significantly associated with age and MAP. In longitudinal analysis, annual progression of PWV was not associated with historic MAP (standardized beta coefficient [β]=-0.02, P=0.698), weakly associated with baseline MAP (β=0.09, P=0.049) but strongly associated with progression (from baseline to most recent measurement) of MAP (β= 0.26, P<0.001). Progression of MAP associated with both baseline and progression of PWV (β=0.13, P=0.003 and β=0.24, P<0.001, respectively). CONCLUSIONS: Progression of aortic stiffness associates more strongly with contemporaneous MAP compared with historic MAP. In contrast, progression of MAP is associated with prior arterial stiffness. These findings suggest a bidirectional relationship between arterial stiffness and blood pressure, and that lowering blood pressure may prevent a cycle of arterial stiffening and hypertension

Integrated multiomics approach identifies calcium and integrin-binding protein-2 as a novel gene for pulse wave velocity

Background: Carotid-femoral pulse wave velocity (PWV) is an important measure of arterial stiffness, which is an independent predictor of cardiovascular morbidity and mortality. In this study, we used an integrated genetic, epigenetic and transcriptomics approach to uncover novel molecular mechanisms contributing to PWV. Methods and results: We measured PWV in 1505 healthy twins of European descendent. A genomewide association analysis was performed using standardized residual of the inverse of PWV. We identified one single-nucleotide polymorphism (rs7164338) in the calcium and integrin-binding protein-2 (CIB2) gene on chromosome 15q25.1 associated with PWV [beta = -0.359, standard error (SE) = 0.07, P = 4.8 x 10(-8)]. The same variant was also associated with increased CIB2 expression in leucocytes (beta = 0.034, SE = 0.008, P = 4.95 x 10(-5)) and skin (beta = 0.072, SE = 0.01, P = 2.35 x 10(-9)) and with hypomethylation of the gene promoter (beta = -.899, SE = 0.098, P = 3.63 x 10(-20)). Conclusion: Our data indicate that reduced methylation of the CIB2 promoter in individuals carrying rs7164338 may lead to increased CIB2 expression. Given that CIB2 is thought to regulate intracellular calcium levels, an increase in protein levels may prevent the accumulation of serum calcium and phosphate, ultimately slowing down the process of vascular calcification. This study shows the power of integrating multiple omics to discover novel cardiovascular mechanisms

Gut microbial diversity is associated with lower arterial stiffness in women

© The Author(s)2018 All rights reserved. Aims The gut microbiome influences metabolic syndrome (MetS) and inflammation and is therapeutically modifiable. Arterial stiffness is poorly correlated with most traditional risk factors. Our aim was to examine whether gut microbial composition is associated with arterial stiffness.Methods We assessed the correlation between carotid-femoral pulse wave velocity (PWV), a measure of arterial stiffness, and and results gut microbiome composition in 617 middle-aged women from the TwinsUK cohort with concurrent serum metabolomics data. Pulse wave velocity was negatively correlated with gut microbiome alpha diversity (Shannon index, Beta(SE)= -0.25(0.07), P = 1 10 -4 ) after adjustment for covariates. We identified seven operational taxonomic units associated with PWV after adjusting for covariates and multiple testing—two belonging to the Ruminococcaceae family. Associations between microbe abundances, microbe diversity, and PWV remained significant after adjustment for levels of gut-derived metabolites (indolepropionate, trimethylamine oxide, and phenylacetylglutamine). We linearly combined the PWV-associated gut microbiome-derived variables and found that microbiome factors explained 8.3% (95% confidence interval 4.3–12.4%) of the variance in PWV. A formal mediation analysis revealed that only a small proportion (5.51%) of the total effect of the gut microbiome on PWV was mediated by insulin resistance and visceral fat, c-reactive protein, and cardiovascular risk factors after adjusting for age, body mass index, and mean arterial pressure. Conclusions Gut microbiome diversity is inversely associated with arterial stiffness in women. The effect of gut microbiome composition on PWV is only minimally mediated by MetS. This first human observation linking the gut microbiome to arterial stiffness suggests that targeting the microbiome may be a way to treat arterial ageing

Integrated multiomics approach identifies calcium and integrin-binding protein-2 as a novel gene for pulse wave velocity

Background: Carotid-femoral pulse wave velocity (PWV) is an important measure of arterial stiffness, which is an independent predictor of cardiovascular morbidity and mortality. In this study, we used an integrated genetic, epigenetic and transcriptomics approach to uncover novel molecular mechanisms contributing to PWV. Methods and results: We measured PWV in 1505 healthy twins of European descendent. A genomewide association analysis was performed using standardized residual of the inverse of PWV. We identified one single-nucleotide polymorphism (rs7164338) in the calcium and integrin-binding protein-2 (CIB2) gene on chromosome 15q25.1 associated with PWV [beta = -0.359, standard error (SE) = 0.07, P = 4.8 x 10(-8)]. The same variant was also associated with increased CIB2 expression in leucocytes (beta = 0.034, SE = 0.008, P = 4.95 x 10(-5)) and skin (beta = 0.072, SE = 0.01, P = 2.35 x 10(-9)) and with hypomethylation of the gene promoter (beta = -.899, SE = 0.098, P = 3.63 x 10(-20)). Conclusion: Our data indicate that reduced methylation of the CIB2 promoter in individuals carrying rs7164338 may lead to increased CIB2 expression. Given that CIB2 is thought to regulate intracellular calcium levels, an increase in protein levels may prevent the accumulation of serum calcium and phosphate, ultimately slowing down the process of vascular calcification. This study shows the power of integrating multiple omics to discover novel cardiovascular mechanisms

Molecular Mechanisms of Arterial Stiffening

Stiffening of large arteries is a hallmark of vascular aging and one of the most important determinants of the age-related increase in blood pressure and cardiovascular disease events. Despite a substantial genetic component, the molecular mechanisms underlying phenotypic variability in arterial stiffness remain unknown. Previous genetic studies have identified several genetic variants that are associated with measures of arterial stiffness. Here, we review the relevant advances in the identification of pathways underlying arterial stiffness from genomic studies

Role of arterial stiffness in cardiovascular disease

Propagation of the pressure wave along the arterial tree (pulse wave velocity [PWV]) is related to the intrinsic elasticity of the arterial wall. PWV is increased in stiffer arteries and, when measured over the aorta, is an independent predictor of cardiovascular morbidity and mortality. Given the predictive power of PWV, identifying strategies that prevent or reduce stiffening may be important in prevention of cardiovascular events. One view is that aortic stiffness occurs as a result of atherosclerosis along the aorta. However, there is little or no association between PWV and classical risk factors for atherosclerosis, other than age and blood pressure. Furthermore, PWV does not increase during early stages of atherosclerosis, as measured by intima-media thickness and noncalcified atheroma, but it does increase in the presence of aortic calcification that occurs within advanced atherosclerotic plaque. Age-related widening of pulse pressure is the major cause of age-related increase in prevalence of hypertension and has been attributed to arterial stiffening. This review summarizes the methods of measuring aortic stiffness in humans, the pathophysiological mechanisms leading to aortic stiffness, including its association with atherosclerosis, and the haemodynamic consequences of increased aortic stiffness