Elasticity indices of large and small arteries in relation to the metabolic syndrome in Chinese

Arterial stiffness in fertile women with metabolic syndrome

INTRODUCTION

Although metabolic syndrome (MetS) is evidently associated with the risk of cardiovascular disease (CVD), recently its use has been questioned. We studied the utility of MetS diagnosis when estimating individual CVD risk.

METHODS

We compared 27 fertile women with MetS and 27 counterparts without the syndrome, matched pairwise according to well-known risk factors of CVD. Pulse wave velocity (PWV) and central blood pressure (cBP) were determined noninvasively via a SphygmoCor device. Arterial compliance was measured noninvasively with an HDI/PulseWave^TMCR-2000 arterial tonometer.

RESULTS

PWV (7.1 ± 2.5 versus 6.5 ± 1.1 m/s, p = .037), and both systolic (120.9 ± 12.2 versus 111.5 ± 16.0 mmHg, p = .031) and diastolic cBP (81.3 ± 8.5 versus 74.1 ± 11.2 mmHg, p = .035) were higher in the MetS group. Systemic arterial compliance values were lower in both large (15.1 ± 8.0 versus 16.1 ± 4.4 mL/mmHg × 10, p = .034) and small arteries (7.1 ± 2.5 versus 9.3 ± 3.2 mL/mmHg ×100, p = .010) in women with MetS.

CONCLUSIONS

Fertile women with MetS had increased arterial stiffness, as measured by three different methods. Our results highlight the utility of MetS when revealing increased individual CVD risks in fertile-aged women. Key messages Women with MetS have increased arterial stiffness when measured by different methods. MetS is a useful clinical tool to assess increased cardiovascular risk, particularly among fertile-aged women.

Ozone exposure is associated with acute changes in inflammation, fibrinolysis, and endothelial cell function in coronary artery disease patients

BACKGROUND

Air pollution is a major risk factor for cardiovascular disease, of which ozone is a major contributor. Several studies have found associations between ozone and cardiovascular morbidity, but the results have been inconclusive. We investigated associations between ozone and changes across biological pathways associated with cardiovascular disease.

METHODS

Using a panel study design, 13 participants with coronary artery disease were assessed for markers of systemic inflammation, heart rate variability and repolarization, lipids, blood pressure, and endothelial function. Daily measurements of ozone and particulate matter (PM2.5) were obtained from central monitoring stations. Single (ozone) and two-pollutant (ozone and PM2.5) models were used to assess percent changes in measurements per interquartile ranges of pollutants.

RESULTS

Per interquartile increase in ozone, changes in tissue plasminogen factor (6.6%, 95% confidence intervals (CI) = 0.4, 13.2), plasminogen activator inhibitor-1 (40.5%, 95% CI = 8.7, 81.6), neutrophils (8.7% 95% CI = 1.5, 16.4), monocytes (10.2%, 95% CI = 1.0, 20.1), interleukin-6 (15.9%, 95% CI = 3.6, 29.6), large-artery elasticity index (-19.5%, 95% CI = -34.0, -1.7), and the baseline diameter of the brachial artery (-2.5%, 95% CI = -5.0, 0.1) were observed. These associations were robust in the two-pollutant model.

CONCLUSIONS

We observed alterations across several pathways associated with cardiovascular disease in 13 coronary artery disease patients following ozone exposures, independent of PM2.5. The results support the biological plausibility of ozone-induced cardiovascular effects. The effects were found at concentrations below the EPA National Ambient Air Quality Standards for both ozone and PM2.5.

Arterial elasticity and oxidized LDL among men with metabolic syndrome and different 10-year cardiovascular risk estimated by FINRISK and SCORE models

BACKGROUND

SCORE and FINRISK models are designed to estimate patient's risk for cardiovascular diseases (CVD). Increased circulating oxidized LDL (oxLDL) and impaired arterial elasticity, on their part, are considered as markers of subclinical atherosclerosis. Subjects with metabolic syndrome (MetS) are thought to be at high risk for CVD because of metabolic abnormalities.

AIM

To study among men with MetS whether subjects with three, four, or five MetS variables or different estimated 10-year CVD risk differ in oxLDL and arterial elasticity.

METHODS

OxLDL was assessed by a capture ELISA and arterial elasticity by a radial artery tonometer among 120 men with MetS. Ten-year CVD risk was calculated for those without CVD or statin medication by FINRISK and SCORE at the actual age and at the extrapolated age of 60. Results. High-risk subjects by FINRISK and SCORE had impaired arterial elasticity. In addition, high-risk subjects by FINRISK at the extrapolated age had elevated oxLDL levels. The number of MetS variables did not associate with arterial elasticity or oxLDL.

CONCLUSION

Among men with MetS, estimation of 10-year CVD risk, especially when extrapolated to age 60, seems to differentiate subjects with respect to markers of subclinical atherosclerosis. Trial registration. ClinicalTrials.gov NCT01119404.

Physical activity modifies the association between CYBA gene polymorphisms and small artery elasticity in a Chinese population

Emerging evidence suggests that increased superoxide production is responsible for a significant proportion of endothelial dysfunction. The relationship between variants of the CYBA gene and cardiovascular diseases is currently debated. In the present study, we investigated the influence of CYBA polymorphisms (rs1049255 and rs7195830) on arterial elasticity in a Chinese population. In the 2178 participants enrolled in the GaoYou study, we measured large artery elasticity (C1) and small artery elasticity (C2) non-invasively, genotyped the CYBA polymorphisms and calculated energy expenditure. The AA genotype of the rs1049255 polymorphism was associated with a lower C2 than were the GG/AG genotypes (5.31±0.11 vs. 5.52±0.06 ml mm Hg(-1) × 100; P=0.01). Further analyses revealed an interaction between CYBA polymorphisms and physical activity with respect to C2 (P=0.007 for rs1049255 and P=0.038 for rs7195830). In less physically active participants, the AA genotype of the rs1049255 polymorphism was associated with a significantly lower C2 than the GG/AG genotypes (4.69±0.16 vs. 5.26±0.19 ml mm Hg(-1) × 100; P=0.008). In physically active participants, the GG/AG genotypes of rs7195830 polymorphism were correlated with higher C2 values than the AA genotype (5.84±0.08 vs. 5.08±0.32 ml mm Hg(-1) × 100; P=0.049). Haplotype analyses revealed higher C2 values in rs1049255G-rs7195830G carriers (P=0.0015). In conclusion, the rs1049255 and rs7195830 polymorphisms of the CYBA gene were associated with C2 in a Chinese population; physical activity could modify this genetic effect.

A novel photoplethysmography technique to derive normalized arterial stiffness as a blood pressure independent measure in the finger vascular bed

Stiffening of the small artery may be the earliest sign of arteriosclerosis. However, there is no adequate method for directly assessing small arterial stiffness. In this study, the finger arterial elasticity index (FEI) was defined as the parameter n which denotes the curvilinearity of an exponential model of pressure (P)-volume (V(a)) relationship (V(a) = a - b exp (-nP)). For the original estimation, the FEI was calculated from a compliance index from the finger photoplethysmogram whilst occluding the finger. A simple estimation of the FEI was devised by utilizing normalized pulse volume instead of the compliance index. Both estimations yielded close agreement with the exponential model in healthy young participants (study 1: n = 19). Since the FEI was dependent on finger mean blood pressure, normalized finger arterial stiffness index (FSI) was defined as standardized residual from their relationship: mean and standard deviation (SD) of the FSI were 50 ± 10 (study 2: n = 174). The mean coefficient of variation of the FSI for four measurements was 5.72% (study 3: n = 6). The mean and SD of the FSI in seven arteriosclerotic patients were 100.0 ± 13.5. In conclusion, the FEI and FSI by simple estimation are valid and useful for arteriosclerosis research.

Erectile dysfunction, physical activity and metabolic syndrome: differences in markers of atherosclerosis

Background

Erectile dysfunction (ED), impaired arterial elasticity, elevated resting heart rate as well as increased levels of oxidized LDL and fibrinogen associate with future cardiovascular events. Physical activity is crucial in the prevention of cardiovascular diseases (CVD), while metabolic syndrome (MetS) comprises an increased risk for CVD events. The aim of this study was to assess whether markers of subclinical atherosclerosis are associated with the presence of ED and MetS, and whether physical activity is protective of ED.

Methods

57 MetS (51.3 ± 8.0 years) and 48 physically active (PhA) (51.1 ± 8.1 years) subjects participated in the study. ED was assessed by the International Index of Erectile Function (IIEF) questionnaire, arterial elasticity by a radial artery tonometer (HDI/PulseWave™ CR-2000) and circulating oxLDL by a capture ELISA immunoassay. Fibrinogen and lipids were assessed by validated methods. The calculation of mean daily energy expenditure of physical exercise was based on a structured questionnaire.

Results

ED was more often present among MetS compared to PhA subjects, 63.2% and 27.1%, respectively (p < 0.001). Regular physical exercise at the level of > 400 kcal/day was protective of ED (OR 0.12, 95% CI 0.017-0.778, p = 0.027), whereas increased fibrinogen (OR 4.67, 95% CI 1.171-18.627, p = 0.029) and elevated resting heart rate (OR 1.07, 95% CI 1.003-1.138, p = 0.04) were independently associated with the presence of ED. In addition, large arterial elasticity (ml/mmHgx10) was lower among MetS compared to PhA subjects (16.6 ± 4.0 vs. 19.6 ± 4.2, p < 0.001), as well as among ED compared to non-ED subjects (16.7 ± 4.6 vs. 19.0 ± 3.9, p = 0.008). Fibrinogen and resting heart rate were highest and large arterial elasticity lowest among subjects with both MetS and ED.

Conclusions

Markers of subclinical atherosclerosis associated with the presence of ED and were most evident among subjects with both MetS and ED. Thus, especially MetS patients presenting with ED should be considered at high risk for CVD events. Physical activity, on its part, seems to be protective of ED.

Trial registration

ClinicalTrials.gov NCT01119404

Circulating oxidized low-density lipoproteins and arterial elasticity: comparison between men with metabolic syndrome and physically active counterparts

Background

Accumulation of oxidized low-density lipoproteins in the intimae of arteries and endothelial dysfunction are key events in the development of atherosclerosis. Patients with metabolic syndrome are at high risk for cardiovascular diseases but the linkage between metabolic syndrome and atherosclerosis is incompletely understood. We studied whether the levels of oxidized LDL and arterial elasticity differ between metabolic syndrome patients and physically active controls.

Methods

40 men with metabolic syndrome and 40 physically active controls participated in this cross-sectional study. None of the study subjects had been diagnosed with cardiovascular disease. Levels of oxidized LDL were assessed by a two-site ELISA immunoassay. Arterial elasticity was assessed non-invasively by the HDI/PulseWave™ CR-2000 arterial tonometer.

Results

Levels of oxidized LDL were 89.6 ± 33.1 U/L for metabolic syndrome subjects and 68.5 ± 23.6 U/L for controls (p = 0.007). The difference remained significant after adjustment for LDL cholesterol. Large artery elasticity index (C1) was 16.2 ± 4.1 mL/mmHgx10 for metabolic syndrome subjects and 19.4 ± 3.7 mL/mmHgx10 for controls (p = 0.001), small artery indices (C2) were 7.0 ± 3.2 mL/mmHgx100 and 6.5 ± 2.9 mL/mmHgx100 (NS), respectively.

Conclusions

Subjects with metabolic syndrome had elevated levels of oxidized LDL and reduced large arterial elasticity compared to controls. This finding may partly explain the increased risk for cardiovascular diseases among metabolic syndrome patients.

Trial registration

ClinicalTrials.gov NCT01114763