Arterial stiffening relates to arterial calcification but not to noncalcified atheroma in women. A twin study

Do Photopletysmographic Parameters of Arterial Stiffness Differ Depending on the Presence of Arterial Hypertension and/or Atherosclerosis?

BACKGROUND

Hypertension and atherosclerotic cardiovascular diseases (ASCVD) increase cardiovascular risk and worsen patients' prognoses. One early predictor of increased risk is a change in arterial stiffness. This study aimed to evaluate arterial stiffness parameters using the non-invasive photoplethysmography (PPG) method in Polish patients with arterial hypertension (AH) and/or atherosclerosis (AS).

METHODS

The study group consisted of 333 patients (Caucasians, both sexes, aged 30-85 years old). Patients were analyzed in four groups depending on AH and AS (Group I: patients without AH or AS, Group II: AH patients, Group III: AS patients, and Group IV: AH/AS patients) and, in addition, according to sex and history of SARS-CoV-2 infection. Arterial stiffness parameters, i.e., reflection index (RI), peak-to-peak time (PPT), and stiffness index (SI) were automatically calculated with PPG based on the analysis of the pulse wave contour.

RESULTS

Mean values of RI and SI were higher in men than women (p < 0.001 each). Diastolic blood pressure (DBP) also differed between sexes (p = 0.010). Mean SI values differed between the study groups (p = 0.038) with the highest SI found in AS/AH patients and the lowest-in patients without AH or AS. The mean SI values were significantly lower in women compared to men in both Group I and Group II (p = 0.006 and p < 0.001, respectively). The mean values of RI were also greater in men than in women in Group I and Group II (p < 0.001 for each group). Regarding COVID-19 history, only HR values differed between patients with and without COVID-19 in AH patients (p = 0.012). In AH patients, men had higher values of RI and SI compared to women (p < 0.001 and p < 0.001). On the other hand, AS women with COVID-19 had significantly greater mean values of SI (9.66 m/s ± 1.61) than men with COVID-19 (7.98 m/s ± 1.09) (p = 0.045).

CONCLUSIONS

The present study confirmed that sex had a significant impact on arterial stiffness parameters. Both AH and AS affected arterial stiffness. Heart rate was greater in hypertensive patients after COVID-19 compared to hypertensive patients without COVID-19.

Aortic Calcification is Associated With the Difference Between Invasive Central and Cuff-Measured Brachial Blood Pressure in Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) is associated with accelerated vascular calcification and increased central systolic blood pressure when measured invasively (invCSBP) relative to cuff-based brachial systolic blood pressure (cuffSBP). The contribution of aortic wall calcification to this phenomenon has not been clarified. We, therefore, examined the effects of aortic calcification on cuffSBP and invCSBP in a cohort of patients representing all stages of CKD.

METHODS

During elective coronary angiography, invCSBP was measured in the ascending aorta with a fluid-filled catheter with simultaneous recording of cuffSBP using an oscillometric device. Furthermore, participants underwent a non-contrast computed tomography scan of the entire aorta with observer-blinded calcification scoring of the aortic wall ad modum Agatston.

RESULTS

We included 168 patients (mean age 67.0 ± 10.5, 38 females) of whom 38 had normal kidney function, while 30, 40, 28, and 32 had CKD stages 3a, 3b, 4, and 5, respectively. Agatston scores adjusted for body surface area ranged from 48 to 40,165. We found that invCSBP increased 3.6 (95% confidence interval 1.4-5.7) mm Hg relative to cuffSBP for every 10,000-increment in aortic Agatston score. This association remained significant after adjustment for age, diabetes, antihypertensive treatment, smoking, eGFR, and BP level. No such association was found for diastolic BP.

CONCLUSIONS

Patients with advanced aortic calcification have relatively higher invCSBP for the same cuffSBP as compared to patients with less calcification. Advanced aortic calcification in CKD may therefore result in hidden central hypertension despite apparently well-controlled cuffSBP. ClinicalTrials.gov identifier: NCT04114695.

Leucine-Rich Alpha-2 Glycoprotein 1 Accumulates in Complicated Atherosclerosis and Promotes Calcification

Atherosclerosis is the primary cause of cardiovascular disease. The development of plaque complications, such as calcification and neo-angiogenesis, strongly impacts plaque stability and is a good predictor of mortality in patients with atherosclerosis. Despite well-known risk factors of plaque complications, such as diabetes mellitus and chronic kidney disease, the mechanisms involved are not fully understood. We and others have identified that the concentration of circulating leucine-rich α-2 glycoprotein 1 (LRG1) was increased in diabetic and chronic kidney disease patients. Using apolipoprotein E knockout mice (ApoE-/-) (fed with Western diet) that developed advanced atherosclerosis and using human carotid endarterectomy, we showed that LRG1 accumulated into an atherosclerotic plaque, preferentially in calcified areas. We then investigated the possible origin of LRG1 and its functions on vascular cells and found that LRG1 expression was specifically enhanced in endothelial cells via inflammatory mediators and not in vascular smooth muscle cells (VSMC). Moreover, we identified that LRG1 was able to induce calcification and SMAD1/5-signaling pathways in VSMC. In conclusion, our results identified for the first time that LRG1 is a direct contributor to vascular calcification and suggest a role of this molecule in the development of plaque complications in patients with atherosclerosis.

A two-sample Mendelian randomization study of atherosclerosis and dementia

The causality between atherosclerosis and dementia remains unclear. This study aimed to explore the causal effect of atherosclerosis related indicators on dementia risk based on two-sample Mendelian randomization (MR) using summary statistics of genome-wide association studies (GWASs). The inverse variance weighted (IVW) method was performed as the main analysis, supplemented by different sensitivity analyses. Suggestive evidence indicated that peripheral arterial disease (PAD) (odds ratio (OR): 0.864, 95% confidence interval (CI): 0.797-0.937), coronary atherosclerosis (CoAS) (OR: 0.927, 95% CI: 0.860-0.998) and atherosclerosis, excluding cerebral, coronary, and PAD (ATHSCLE) (OR: 0.812, 95% CI: 0.725-0.909) were inversely associated with the risk of AD. The sensitivity analysis confirmed a suggestive reverse effect of ATHSCLE on the risk of frontotemporal dementia (FTD) (OR, 0.812, 95% CI, 0.725-0.909). Findings provide suggestive evidence that PAD, CoAS, and ATHSCLE might be associated with the risk of AD or FTD, which requires further exploration in larger samples.

Vascular ageing: moving from bench towards bedside

Prevention of cardiovascular disease (CVD) remains one of the largest public health challenges of our time. Identifying individuals at increased cardiovascular risk at an asymptomatic, sub-clinical stage is of paramount importance for minimizing disease progression as well as the substantial health and economic burden associated with overt CVD. Vascular ageing (VA) involves the deterioration in vascular structure and function over time and ultimately leads to damage in the heart, brain, kidney, and other organs. Vascular ageing encompasses the cumulative effect of all cardiovascular risk factors on the arterial wall over the life course and thus may help identify those at elevated cardiovascular risk, early in disease development. Although the concept of VA is gaining interest clinically, it is seldom measured in routine clinical practice due to lack of consensus on how to characterize VA as physiological vs. pathological and various practical issues. In this state-of-the-art review and as a network of scientists, clinicians, engineers, and industry partners with expertise in VA, we address six questions related to VA in an attempt to increase knowledge among the broader medical community and move the routine measurement of VA a little closer from bench towards bedside.

Aortic calcification: A postmortem CT validation study in a middle-aged population

BACKGROUND

Computed tomography (CT)-detected aortic calcification is strongly associated with aortic stiffness and is an accurate predictor of cardiovascular and all-cause mortality and cognitive decline. Some previous pathologic studies have shown calcium accumulation in the medial layer of the vessel wall, while others have suggested localisation in the atherosclerotic intimal layer.

OBJECTIVES

The aim of this study was to histologically validate CT findings of aortic calcification for detectability and location in the aortic wall.

METHODS

We acquired postmortem CT images and collected 170 aortic tissue samples from five different locations in the thoracic and abdominal aorta of 40 individuals who underwent autopsy. Microscopic slides were stained with haematoxylin and eosin and elastic van Gieson stain. Calcified lesions were characterised and calcifications were manually annotated in the intima and media. The presence and morphology of calcifications were scored on CT images.

RESULTS

The mean age of the autopsied individuals was 63 years, and 28 % died of cardiovascular disease. Calcifications were present in 74/170 (44 %) samples. Calcification was more common in the abdominal aorta than in the thoracic aorta. In all samples with calcifications, 99 % were located in the intimal layer. Only 16/170 samples had a small amount of medial arterial calcification. The histological results showed an 85 % concordance for the presence or absence of CT calcifications. There was complete inter-method agreement for annularity of calcifications in 68 % of the samples (linear weighted kappa 0.68 (95 %CI 0.60-0.77).

CONCLUSIONS

Aortic calcifications visible on CT are located in the intimal layer of the abdominal aorta wall, at least in aortas that are not aneurysmatic or dissected. The presence and annularity of these calcifications can be reliably determined by CT.

Relation of Pulse Wave Velocity to Contemporaneous and Historical Blood Pressure in Female Twins

BACKGROUND

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.

Carotid Artery Stiffness: Imaging Techniques and Impact on Cerebrovascular Disease

Arterial stiffness is an important measure of vascular aging and atherosclerosis. Though it is measured in many well-known epidemiologic cohort studies, arterial stiffness is often overlooked in routine clinical practice for a number of reasons including difficulties in measurement, variations in definition, and uncertainties surrounding treatment. Central arterial stiffness, a surrogate for aortic stiffness, is the most commonly measured marker of arterial stiffness. In addition to central stiffness, there are also a number of ultrasound based techniques to measure local vascular stiffness, including carotid stiffness. There is evidence that both local carotid stiffness and central arterial stiffness measures are associated with multiple cerebrovascular processes, including stroke and cognitive dysfunction. Mechanistic explanations supporting this association include increased flow load experienced by the cerebral microvasculature leading to cerebral parenchymal damage. In this article, we review definitions of carotid artery stiffness measures and pathophysiologic mechanisms underpinning its association with plaque development and downstream cerebral pathology. We will review the evidence surrounding the association of carotid stiffness measures with downstream manifestations including stroke, cerebral small vessel disease detected on brain MR such as white matter hyperintensities and covert brain infarctions, brain atrophy, and cognitive dysfunction. With consistent definitions, measurement methods, and further scientific support, carotid stiffness may have potential as an imaging-based risk factor for stroke and cognitive decline.

The effect of vitamin K1 on arterial calcification activity in subjects with diabetes mellitus: a post hoc analysis of a double-blind, randomized, placebo-controlled trial

BACKGROUND

Coronary and aortic artery calcifications are generally slow to develop, and their burden predicts cardiovascular disease events. In patients with diabetes mellitus, arterial calcification is accelerated and calcification activity can be detected using 18F-sodium fluoride positron emission tomography (18F-NaF PET).

OBJECTIVES

We aimed to determine whether vitamin K1 supplementation inhibits arterial calcification activity in individuals with diabetes mellitus.

METHODS

This was a post hoc analysis of the ViKCoVaC (effect of Vitamin-K1 and Colchicine on Vascular Calcification activity in subjects with Diabetes Mellitus) double-blind randomized controlled trial conducted in Perth, Western Australia. Individuals with diabetes mellitus and established coronary calcification (coronary calcium score > 10), but without clinical coronary artery disease, underwent baseline 18F-NaF PET imaging, followed by oral vitamin K1 supplementation (10 mg/d) or placebo for 3 mo, after which 18F-NaF PET imaging was repeated. We tested whether individuals randomly assigned to vitamin K1 supplementation had reduced development of new 18F-NaF PET positive lesions within the coronary arteries and aorta.

RESULTS

In total, 149 individuals completed baseline and follow-up imaging studies. Vitamin K1 supplementation independently decreased the odds of developing new 18F-NaF PET positive lesions in the coronary arteries (OR: 0.35; 95% CI: 0.16, 0.78; P = 0.010), aorta (OR: 0.27; 95% CI: 0.08, 0.94; P = 0.040), and in both aortic and coronary arteries (OR: 0.28; 95% CI: 0.13, 0.63; P = 0.002).

CONCLUSIONS

In individuals with diabetes mellitus, supplementation with 10 mg vitamin K1/d may prevent the development of newly calcifying lesions within the aorta and the coronary arteries as detected using 18F-NaF PET. Further long-term studies are needed to test this hypothesis.This trial was registered at anzctr.org.au as ACTRN12616000024448.

Arterial Stiffness as a Cardiovascular Risk Factor for the Development of Preeclampsia and Pharmacopreventive Options

Arterial stiffness (AS) describes the rigidity of the arterial walls. Epidemiological studies have shown that increased AS is an independent predictive marker of cardiovascular (CV) morbidity and mortality in both pregnant and non-pregnant women. Preeclampsia (PE), a form of pregnancy-induced hypertension, affects approximately 5% of pregnancies worldwide. Preeclamptic women have a higher risk of CV disease (CVD), mainly because PE damages the heart's ability to relax between contractions. Different pharmacological approaches for the prevention of PE have been tested in clinical trials (e.g. aspirin, enoxaparin, metformin, pravastatin, and sildenafil citrate). In current clinical practice, only low-dose aspirin is used for PE pharmacoprevention. However, low-dose aspirin does not prevent term PE, which is the most common form of PE. Compromised vascular integrity precedes the onset of PE and therefore, AS assessment may constitute a promising predictive marker of PE. Several non-invasive techniques have been developed to assess AS. Compared with normotensive pregnancies, both carotid-femoral pulse wave velocity (cfPWV) and augmentation index (AIx) are increased in PE. In view of simplicity, reliability, and reproducibility, there is an interest in oscillometric AS measurements in pregnancies complicated by PE.

Functional versus morphological assessment of vascular age in patients with coronary heart disease

Communicating cardiovascular risk based on individual vascular age (VA) is a well acknowledged concept in patient education and disease prevention. VA may be derived functionally, e.g. by measurement of pulse wave velocity (PWV), or morphologically, e.g. by assessment of carotid intima-media thickness (cIMT). The purpose of this study was to investigate whether both approaches produce similar results. Within the context of the German subset of the EUROASPIRE IV survey, 501 patients with coronary heart disease underwent (a) oscillometric PWV measurement at the aortic, carotid-femoral and brachial-ankle site (PWVao, PWVcf, PWVba) and derivation of the aortic augmentation index (AIao); (b) bilateral cIMT assessment by high-resolution ultrasound at three sites (common, bulb, internal). Respective VA was calculated using published equations. According to VA derived from PWV, most patients exhibited values below chronological age indicating a counterintuitive healthier-than-anticipated vascular status: for VAPWVao in 68% of patients; for VAAIao in 52% of patients. By contrast, VA derived from cIMT delivered opposite results: e.g. according to VAtotal-cIMT accelerated vascular aging in 75% of patients. To strengthen the concept of VA, further efforts are needed to better standardise the current approaches to estimate VA and, thereby, to improve comparability and clinical utility.

Thoracic Aortic Calcification and Pre-Clinical Hypertension by New 2017 ACC/AHA Hypertension Guidelines

The recently revised 2017 American College of Cardiology/American Heart Association (ACC/AHA) hypertension (HTN) guidelines employ a lower blood pressure threshold to define HTN, aiming for earlier prevention of HTN-related cardiovascular diseases (CVD). Thoracic aortic calcification (TAC), a new surrogate marker of aging and aortic medial layer degeneration, and different stages of HTN, according to the 2017 ACC/AHA HTN guidelines, remain unknown. We classified 3022 consecutive asymptomatic individuals enrolled into four HTN categories using the revised 2017 ACC/AHA guidelines: normal blood pressure (NBP), elevated blood pressure (EBP), and stage 1 (S1) and stage 2 (S2) HTN. The coronary artery calcification score and TAC metrics (total Agaston TAC score, total plaque volume (mm³), and mean density (Hounsfield units, HU)) were measured using multi-detector computed tomography. Compared to NBP, a graded and significant increase in the TAC metrics was observed starting from EBP and S1 and S2 HTN, using the new 2017 ACC/AHA guidelines (NBP as reference; all trends: p < 0.001). These differences remained consistent after being fully adjusted. Older age (>50 years), S1 and S2 HTN, prevalent diabetes, and chronic kidney disease (<60 mL/min/1.73 m²) are all independently contributing factors to higher TAC risk using multivariate stepwise logistic regressions (all p ≤ 0.001). The optimal cutoff values of systolic blood pressure, diastolic blood pressure, and pulse pressure were 121, 74, and 45 mmHg, respectively, for the presence of TAC after excluding subjects with known CVD and ongoing HTN medication treatment. Our data showed that the presence of TAC starts at a stage of elevated blood pressure not categorized as HTN from the updated 2017 ACC/AHA hypertension guidelines.

Heritability of Cardiothoracic Ratio and Aortic Arch Calcification in Twins

Background and Objectives: Aortic arch calcification (AoAC) is associated with a variety of cardiovascular complications. The measurement and grading of AoAC using posteroanterior (PA) chest X-rays are well established. The cardiothoracic ratio (CTR) can be simultaneously measured with PA chest X-rays and used as an index of cardiomegaly. The genetic and environmental contributions to the degree of the AoAC and CTR are not well understood. The purpose of this study was to investigate the effect of genetics and environmental factors on the AoAC and CTR. Materials and Methods: A total of 684 twins from the South Korean twin registry (261 monozygotic, MZ and 81 dizygotic, DZ pairs; mean age 38.6 ± 7.9 years, male/female = 264/420) underwent PA chest X-rays. Cardiovascular risk factors and anthropometric data were also collected. The AoAC and CTR were measured and graded using a standardized method. A structural equation method was used to calculate the proportion of variance explained by genetic and environmental factors behind AoAC and CTR. Results: The within-pair differences were low regarding the grade of AoAC, with only a few twin pairs showing large intra-pair differences. We found that the thoracic width showed high heritability (0.67, 95% CI: 0.59–0.73, p = 1). Moderate heritability was detected regarding cardiac width (0.54, 95% CI: 0.45–0.62, p = 0.572) and CTR (0.54, 95% CI: 0.44–0.62, p = 0.701). Conclusions: The heritable component was significant regarding thoracic width, cardiac width, and the CTR.

Decreased heritability and emergence of novel genetic effects on pulse wave velocity from youth to young adulthood

Increased arterial stiffness measured by pulse wave velocity (PWV) is an important parameter in the assessment of cardiovascular risk. Our previous longitudinal study has demonstrated that carotid-distal PWV showed reasonable stability throughout youth and young adulthood. This stability might be driven by genetic factors that are expressed consistently over time. We aimed to illustrate the relative contributions of genetic and environmental factors to the stability of carotid-distal PWV from youth to young adulthood. We also examined potential ethnic differences. For this purpose, carotid-distal PWV was measured twice in 497 European American (EA) and African American (AA) twins, with an average interval time of 3 years. Twin modelling on PWV showed that heritability decreased over time (62–35%), with the nonshared environmental influences becoming larger. There was no correlation between the nonshared environmental factors on PWV measured at visit 1 and visit 2, with the phenotypic tracking correlation (r = 0.32) completely explained by shared genetic factors over time. Novel genetic influences were identified accounting for a significant part of the variance (19%) at the second measurement occasion. There was no evidence for ethnic differences. In summary, novel genetic effects appear during development into young adulthood and account for a considerable part of the variation in PWV. Environmental influences become larger with age for PWV.

Impact of abdominal aortic calcification on 90-day mortality in sepsis patients: a pilot retrospective cohort study

Aim

We aimed to investigate the association between aortic calcification and 90-day mortality in sepsis patients admitted to the intensive care unit.

Methods

We evaluated adult patients (≥18 years) diagnosed with sepsis based on the Sepsis-3 criteria and admitted to our intensive care unit between April 2011 and March 2015. They were classified according to the degree of abdominal aortic calcification (severe and non-severe), grouped per age (<65, 65-75, and >75 years), and matched. Survival curves were generated, and between-group differences were evaluated.

Results

Overall, 164 patients were included. The Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores were not significantly different between the severity groups, whereas there were significant differences in age (P < 0.001), sex (P = 0.017), and presence of diabetes mellitus (P < 0.001), hypertension (P < 0.001), dyslipidemia (P = 0.048), and maintenance dialysis (P = 0.001). The severe abdominal aortic calcification group showed significantly poorer prognosis than the non-severe group (log-rank P = 0.009). The adjusted odds ratio of severe calcification was the highest in patients aged <65 years (7.167; 95% confidence interval, 1.042-49.28, P = 0.045). Twenty-eight patients from each group were matched. The 90-day survival rate of the severe calcification group remained significantly lower than that of the non-severe calcification group (53.6% [15/28] versus 82.1% [23/28], P = 0.022).

Conclusions

Severe abdominal aortic calcification is associated with the 90-day mortality of sepsis patients, particularly among those aged <65 years. Thus, caution is necessary in patients younger than 65 years; they may need to be treated with as much care as the elderly.

Arterial Stiffness Parameters Correlate with Estimated Cardiovascular Risk in Humans: A Clinical Study

Arterial stiffness is said to be a novel predictor of cardiovascular events. This study investigated the correlation between arterial stiffness parameters and the estimated cardiovascular disease risk (RISK) in a Polish cohort of patients divided by age, sex, and body-mass index (BMI). The cross-sectional study enrolled 295 patients who met the inclusion criteria. Subjects were divided into three age groups, four weight groups, and by gender. The stiffness of the vessels was assessed by the measurement of the stiffness index (SI) and reflection index (RI). An individual 10-year RISK was calculated for each patient using the Heart Risk Calculator algorithm by the American Heart Association. A correlation between the SI and estimated RISK was observed (rS 0.42, p < 0.05). The strongest relationship was presented for women, the age group 40-54, and individuals with normal weight. The correlation between RI and calculated RISK was observed (rS 0.19, p < 0.05), the highest correlation was noticed for people aged 40-54 and obese. In conclusion, both SI and RI are correlated with estimated cardiovascular risk, however SI seems to be more useful than RI to predict the individual risk of future cardiovascular events. Both of these can be measured using non-invasive techniques, which demonstrates their potential utility in clinical practice.

Evaluation of aortic 18F-NaF tracer uptake using PET/CT as a predictor of aortic calcification in postmenopausal women: A longitudinal study

Introduction

Aortic calcification as detected by computed tomography is associated with arterial stiffening and is an important predictor of cardiovascular morbidity and mortality. Uptake of ¹⁸F-sodium fluoride (¹⁸F-NaF) in the aortic wall reflects metabolically active areas of calcification. The aim of this study was to determine if ¹⁸F-NaF uptake in the aorta is associated with calcification and progression of calcification as detected by computed tomography.

Methods

Twenty-one postmenopausal women (mean age 62 ± 6 years) underwent assessment of aortic ¹⁸F-NaF uptake using positron emission tomography/computer tomography at baseline and a repeat computed tomography scan after a mean follow-up of 3.8 ± 1.3 years. Tracer uptake was quantified by calculating the target-to-background (TBR) ratios at baseline and follow-up. Calcification was assessed at baseline and follow-up using computed tomography.

Results

Over the follow-up period, aortic calcium volume increased from 0.46 ± 0.62 to 0.71 ± 0.93 cm³ (P < 0.05). However, the change in calcium volume did not correlate with baseline TBR either unadjusted (r = 0.00, P = 1.00) or adjusted for age and baseline calcium volume (beta coefficient = −0.18, P = 0.42). TBR at baseline did not differ between participants with (n = 16) compared to those without (n = 5) progression in calcium volume (2.43 ± 0.46 vs. 2.31 ± 0.38, P = 0.58). In aortic segments identified to have the highest tracer uptake at baseline, calcium volume did not significantly change over the follow-up period (P = 0.41).

Conclusion

In a cohort of postmenopausal women, ¹⁸F-NaF uptake as measured by TBR in the lumbar aorta did not predict progression of aortic calcification as detected by computed tomography over a four-year follow-up.

Total brachial artery reactivity and first time incident coronary heart disease events in a longitudinal cohort study: The multi-ethnic study of atherosclerosis

Background

Brachial artery reactivity (BAR) is usually determined as the maximum brachial artery diameter (BAD) following release of an occluding pressure cuff compared to a BAD before cuff inflation. BAD early after cuff deflation can also serve as baseline for estimating total brachial artery reactivity (TBAR). We investigate whether TBAR is associated with first time coronary heart disease events.

Methods

Participants of the Multi-Ethnic Study of Atherosclerosis (n = 5499) consisting of whites, African-Americans, Chinese and Hispanics were followed longitudinally for a mean of 12.5 years. Brachial artery ultrasound was performed following five minutes of cuff occlusion at the forearm. TBAR was estimated from BAD following cuff release as the difference between maximum and minimum brachial artery diameters divided by the minimum diameter multiplied by 100%. TBAR was added to multivariable Cox proportional hazards models with Framingham risk factors as predictors and time to first coronary heart disease event as outcome.

Results

Average TBAR was 9.7% (9.7 SD). Mean age was 61.7 years, 50.9% women. Increased TBAR was associated with lower risk of CHD events with a hazard rate of 0.78 per SD increase (95% C.I. 0.67, 0.91; p = 0.001). A TBAR below the median of 7.87% (Inter Quartile Range: 4.16%, 13.0%) was associated with a 31% lower risk of coronary heart disease event (Hazard Ratio: 0.69; 95% C.I.: 0.55, 0.87).

Conclusion

TBAR is an independent predictor of first time coronary heart disease events and is exclusively measured after release of a blood pressure occlusion cuff.

Genetic and environmental determinants of longitudinal stability of arterial stiffness and wave reflection: a twin study

BACKGROUND

We aimed at evaluating the impact of genetic and environmental factors on longitudinal changes in aortic pulse wave velocity (aPWV) and aortic augmentation index (aAIx).

METHOD

Three hundred and sixty-eight Italian and Hungarian adult twins (214 monozygotic, 154 dizygotic) underwent repeated evaluations of aPWV and aAIx (TensioMed Arteriograph). Within-individual/cross-wave, cross-twin/within-wave and cross-twin/cross-wave correlations were calculated; bivariate Cholesky models were fitted to calculate additive genetic (A), shared environmental (C) and unique environmental (E) components.

RESULTS

For both aPWV and aAIx, cross-twin correlations in monozygotic pairs (r between 0.35 and 0.56) were all significant and always higher than in dizygotic pairs, both at wave 1 and at wave 2. Heritability and unshared environmental proportion of variance at each wave were substantially time-invariant for aPWV (heritability 0.51, 95% CI 0.36-0.63 at wave 1; 0.49, 95% CI 0.34-0.62 at wave 2), whereas for aAIx, we observed a diminished genetic effect (heritability 0.57, 95% CI 0.45-0.67 at wave 1; 0.37, 95% CI 0.21-0.51 at wave 2). Overlapping genetic factors explained a high proportion (0.88, 95% CI 0.61-1.00) of longitudinal covariance for aPWV, and had a relatively lower impact on aAIx (0.55, 95% CI 0.35-0.70). Genetic correlations of aPWV (r = 0.64, 95% CI 0.42-0.85) and aAIx (r = 0.70, 95% CI 0.52-0.87) between waves were lower than 1, suggesting a potential contribution of novel genetic variance on arterial stiffening.

CONCLUSION

Changes in aPWV and aAIx over time are largely genetically determined. Our results might stimulate further studies on genetic and epigenetic factors influencing the process of vascular ageing.

Relation of arterial stiffness to left ventricular structure and function in healthy women

BACKGROUND

Interactions between the left ventricular (LV) and the arterial system, (ventricular-arterial coupling) are key determinants of cardiovascular function. However, most of studies covered multiple cardiovascular risk factors, which also contributed to the morphological and functional changes of LV. The aim of this study was to examine the relationship between arterial stiffness and LV structure and function in healthy women with a low burden of risk factors.

METHODS

Healthy women from the Twins UK cohort (n = 147, mean age was 54.07 ± 11.90 years) were studied. Arterial stiffness was evaluated by carotid-femoral pulse wave velocity (cf-PWV). LV structure and function were assessed by two-dimensional speckle tracking echocardiography.

RESULTS

cf-PWV was significantly associated with most measures of LV geometry and function, including relative wall thickness (RWT), E/e' ratio, global circumferential and radial strain, apical rotation and LV twist (each p <  0.05), but bore no relation to global longitudinal strain. After adjustment for age, body mass index, blood pressure and heart rate, cf-PWV was significantly correlated with RWT, global circumferential strain, apical rotation and LV twist (β = 0.011, - 0.484, 1.167 and 1.089, respectively, each p ≤  0.05).

CONCLUSIONS

In healthy women with a low burden of risk factors, elevated arterial stiffness was intimately interwoven with increased LV twisting even before LV dysfunction becomes clinically evident.

Vessel stiffness, calcification and osteoporosis. Common pathogenetic components

Atherosclerosis and osteoporosis until recently were regarded as the diseases of modern society, and their simultaneous development was explained just by the increased chances with longevity. Currently, there are studies showing evidence on these diseases in ancient populations, regardless the age and gender. The diseases found in younger age, with the early Egyptian civilization, witness on the common genetic and behavioral risk factors and pathogenetic components, than simple age-related chance. Scientific publications show more and more data on common properties of these diseases and pathogenetic mechanisms. High risk of premature death from atherosclerosis and osteoporosis complications facilitates the search for individual and general predictors of the disorders with the aim of on-time prevention. Treatment of atherosclerosis and osteoporosis presentation events in one patient demands for a range of medications that leads to polypragmasia. The review is focused on common mechanisms of vascular stiffness development, calcification and bone density decrease. Profound understanding might make it to open novel targets for one drug to both diseases, with decreased rate of complications.

Carotid Artery Atherosclerosis: A Review on Heritability and Genetics

Carotid atherosclerosis (CAS) is associated with increased cardiovascular risk, and therefore, assessing the genetic versus environmental background of CAS traits is of key importance. Carotid intima-media-thickness and plaque characteristics seem to be moderately heritable, with remarkable differences in both heritability and presence or severity of these traits among ethnicities. Although the considerable role of additive genetic effects is obvious, based on the results so far, there is an important emphasis on non-shared environmental factors as well. We aimed to collect and summarize the papers that investigate twin and family studies assessing the phenotypic variance attributable to genetic associations with CAS. Genes in relation to CAS markers were overviewed with a focus on genetic association studies and genome-wide association studies. Although the role of certain genes is confirmed by studies conducted on large populations and meta-analyses, many of them show conflicting results. A great focus should be on future studies elucidating the exact pathomechanism of these genes in CAS in order to imply them as novel therapeutic targets.

Arterial stiffening is a heritable trait associated with arterial dilation but not wall thickening: a longitudinal study in the twins UK cohort

Aims

Vascular ageing is characterized by arterial stiffening, dilation, and arterial wall thickening. We investigated the extent to which these changes are related and their heritability during 5 year follow-up in the Twins UK cohort.

Methods and results

Carotid-femoral pulse wave velocity (PWVcf), carotid diameter, carotid distensibility, and carotid intima-media thickness (IMT) were measured in 762 female twins (mean age 57.9 ± 8.6 years) at two time-points over an average follow-up of 4.9 ± 1.5 years. Magnetic resonance imaging (MRI) was performed in a sub-sample of 38 women to measure aortic pulse wave velocity (PWVaorta), diameter, and wall thickness. Heritability of changes in arterial wall properties was estimated using structural equation modelling. Annual increases in PWVcf, carotid diameter, distensibility, and IMT were 0.139 m/s, 0.028 mm, -0.4 kPa-1, and 0.011 mm per year, respectively. In regression analysis, predictors of progression in PWVcf included age, mean arterial pressure (MAP), and heart rate (HR) at baseline, and progression in MAP, HR, and body mass index (BMI). Predictors of progression in IMT included progression in MAP, BMI, and triglyceride levels. Progression of PWV and distensibility correlated with progression in carotid diameter but not with IMT. Heritability of progression of PWVcf, diameter, and IMT was 55%, 21%, and 8%, respectively. In a sub-sample of women that underwent MRI, aortic wall thickness increased by 0.19 mm/year, but aortic wall thickening was not correlated with an increase in lumen diameter or PWVaorta.

Conclusion

Arterial stiffening, as measured by PWVcf, and dilation are heritable but independent of arterial wall thickening. Genetic and cardiovascular risk factors contribute differently to progression of PWV and IMT.

Association of Severity of Coronary Lesions with Bone Mineral Density in Postmenopausal Women

Background

Coronary artery disease (CAD) and osteoporosis (OP) are common diseases in postmenopausal women. In both cross-sectional and longitudinal epidemiologic studies, low bone mass has been related to increased frequency of CAD. However, available data on the relationship between bone mineral density (BMD) and severity of coronary lesions is limited.

Objective

To investigate association between the BMD and severity of coronary lesions assessed by Gensini score in postmenopausal women.

Methods

This study included 122 postmenopausal women who were diagnosed with CAD. These patients were divided into two groups according to the severity of coronary lesions assessed by the Gensini score - patients with mild coronary lesions (Gensini score < 25) and patients with severe coronary lesions (Gensini score ≥ 25). Femoral neck mineral density was measured with dual energy X-ray absorptiometry (DXA).

Results

The study included postmenopausal women aged 64.31 ± 4.71 years, 85 of whom (69.7%) exhibited severe coronary lesions. Participants with severe coronary lesions had a significantly higher T score than did those with mild coronary lesions at the femoral neck (p < 0.05). The mean T-score was −0.84 ± 1.01 in mild coronary lesions group, −1.42 ± 1.39 in severe coronary lesions group (p < 0.05). Multivariable logistic regression analysis showed that osteopenia-osteoporosis at the Femoral neck (odds ratio 2.73; 95% confidence interval 1.06 to 6.13) was associated with an increased risk of developing severe coronary lesions. The multiple regression model showed that T-scores (b = −0.407, SE = 0.151, p=0.007) were the independent predictors of Gensini score.

Conclusion

The relationship between severity of coronary lesions and BMD was significant in postmenopausal women. BMD, a low-cost technique involving minimal radiation exposure, widely used for osteoporosis screening, is a promising marker of severity of coronary lesions.

Glycosylation Profile of Immunoglobulin G Is Cross-Sectionally Associated With Cardiovascular Disease Risk Score and Subclinical Atherosclerosis in Two Independent Cohorts

Supplemental Digital Content is available in the text.

Rationale:

One measure of protein glycosylation (GlycA) has been reported to predict higher cardiovascular risk by reflecting inflammatory pathways.

Objective:

The main objective of this study is to assess the role of a comprehensive panel of IgG glycosylation traits on traditional risk factors for cardiovascular disease and on presence of subclinical atherosclerosis in addition to GlycA.

Methods and Results:

We measured 76 IgG glycosylation traits in 2970 women (age range, 40–79 years) from the TwinsUK cohort and correlated it to their estimated 10-year atherosclerotic cardiovascular disease risk score and their carotid and femoral plaque measured by ultrasound imaging. Eight IgG glycan traits are associated with the 10-year atherosclerotic cardiovascular disease risk score after adjusting for multiple tests and for individual risk factors—5 with increased risk and 3 with decreased risk. These glycans replicated in 967 women from ORCADES cohort (Orkney Complex Disease Study), and 6 of them were also associated in 845 men. A linear combination of IgG glycans and GlycA is also associated with presence of carotid (odds ratio, 1.55; 95% confidence interval, 1.25–1.93; P=7.5×10^-5) and femoral (odds ratio, 1.32; 95% confidence interval, 1.06–1.64; P=0.01) plaque in a subset of women with atherosclerosis data after adjustment for traditional risk factors. One specific glycosylation trait, GP18-the percentage of FA2BG2S1 glycan in total IgG glycans, was negatively correlated with very-low-density lipoprotein and triglyceride levels in serum and with presence of carotid plaque (odds ratio, 0.60; 95% confidence interval, 0.50–0.71; P=5×10^-4).

Conclusions:

We find molecular pathways linking IgG to arterial lesion formation. Glycosylation traits are independently associated with subclinical atherosclerosis. One specific trait related to the sialylated N-glycan is negatively correlated with cardiovascular disease risk, very-low-density lipoprotein and triglyceride serum levels, and presence of carotid plaque.

The Relationship of Pulse Pressure and Bone Mineral Density in Adult USA Population: Analysis of the National Health and Nutritional Examination Survey

BACKGROUND/PURPOSE

Accumulating evidence indicates a relationship between Cardiovascular Disease (CVD) and osteoporosis. Hypertension, a known risk factor for CVD is also associated with low Bone Mineral Density (BMD). We hypothesize that Pulse Pressure (PP); a CVD risk factor is associated with BMD.

METHODS

Data from two consecutive cycles of National Health and Nutritional Examination Survey (NHANES) from 2009-2010 and 2011-2012. Point estimates of demographic variables were calculated using descriptive methods. Study participants were divided into 4 groups based on quartile distribution of PP. Multivariate linear regression analysis was performed to assess the relationship between BMD and PP.

RESULTS

A total of 8,179 NHANES participants were included in the study (Tables 1-3). The cohort's mean age (± SE) was 53.3 years 0.19, mean BMI (± SE) 29.6 kg/m² ± 0.07. PP was significantly higher with increased age, among Blacks (57.4 ± 0.52) and Hispanics (57.5 ± 0.19) compared to whites (53.9 ± 0.29), and for men (57.2 ± 0.16) when compared to women (54.1 ± 0.17), p<0.05. After adjusting for age, sex, race, menopause, body mass index, family history of osteoporosis, PP was associated with femoral neck BMD, β=-0.0005, p<0.05 but was not significantly associated with lumbar spine BMD, β=-0.0002, p=0.07.

CONCLUSION

Our results support the hypothesis that wide PP is associated with low BMD. This negative association was demonstrated at the femoral neck where bone loss and osteoporotic fractures occur at a more advanced stage, further supporting the relationship between atherosclerosis and osteoporosis risk. These findings have the potential for identifying high osteoporotic risk patients among those with wide pulse pressure, providing further indications for bone mineral density testing among these elderly frail patients. Further research is needed to investigate the mechanisms behind the relationship between PP and BMD.

Abdominal aortic calcification on dual-energy X-ray absorptiometry: Methods of assessment and clinical significance

Abdominal aortic calcification (AAC) can be accurately recognized on lateral spine images intended for vertebral fracture assessment, that are obtained with dual-energy X-ray absorptiometry (DXA). Greater amounts of AAC are common in the older population for whom DXA is routinely done, and have been consistently associated with incident atherosclerotic cardiovascular disease (ASCVD) events. AAC has also been associated with incident fractures in some prospective studies, but not in others. However, further research is needed to quantify the extent to which measurement of AAC improves prediction of ASCVD events and its impact on physician and patient ASCVD risk management. Additionally, research to develop better, more precise, automated, quantitative methods of AAC assessment on lateral spine densitometric images will hopefully lead to better prediction of clinical outcomes. In conclusion, although the prime indication for densitometric lateral spine imaging remains vertebral fracture assessment, AAC that is found incidentally on lateral spine images should be reported, so that patients and their health care providers are aware of its presence.

Vascular Smooth Muscle Cells and Arterial Stiffening: Relevance in Development, Aging, and Disease

The cushioning function of large arteries encompasses distension during systole and recoil during diastole which transforms pulsatile flow into a steady flow in the microcirculation. Arterial stiffness, the inverse of distensibility, has been implicated in various etiologies of chronic common and monogenic cardiovascular diseases and is a major cause of morbidity and mortality globally. The first components that contribute to arterial stiffening are extracellular matrix (ECM) proteins that support the mechanical load, while the second important components are vascular smooth muscle cells (VSMCs), which not only regulate actomyosin interactions for contraction but mediate also mechanotransduction in cell-ECM homeostasis. Eventually, VSMC plasticity and signaling in both conductance and resistance arteries are highly relevant to the physiology of normal and early vascular aging. This review summarizes current concepts of central pressure and tensile pulsatile circumferential stress as key mechanical determinants of arterial wall remodeling, cell-ECM interactions depending mainly on the architecture of cytoskeletal proteins and focal adhesion, the large/small arteries cross-talk that gives rise to target organ damage, and inflammatory pathways leading to calcification or atherosclerosis. We further speculate on the contribution of cellular stiffness along the arterial tree to vascular wall stiffness. In addition, this review provides the latest advances in the identification of gene variants affecting arterial stiffening. Now that important hemodynamic and molecular mechanisms of arterial stiffness have been elucidated, and the complex interplay between ECM, cells, and sensors identified, further research should study their potential to halt or to reverse the development of arterial stiffness.

Heritability of the femoral intima media thickness

BACKGROUND

The measurement of femoral intima-media thickness (IMT) is underutilized in the clinical practice, although it is a surrogate marker of cardiovascular disease.

MATERIALS AND METHODS

388 Hungarian and Italian twins (121 monozygotic, 73 dizygotic pairs) underwent bilateral B-mode sonography of femoral arteries. IMT was measured by semiautomated software, where available, or by calipers.

RESULTS

Within-pair correlation in monozygotic twins was higher than in dizygotics for each parameter. Age-, sex- and country-adjusted genetic effect accounted for 43.9% (95% confidence interval, CI 21.3%-65.2%) and 47.2% (95% CI, 31.4%-62.6%) of the variance of common and superficial femoral artery IMT, respectively, and unshared environmental effect for 56.1% (95% CI 34.6%-78.5%) and 52.8% (95% CI, 37.2%-68.5%). These results did not change significantly after correcting for body mass index or central systolic blood pressure.

CONCLUSIONS

Genetic factors have a moderate role in the determination of common and superficial femoral IMT; however, the influence of environmental (lifestyle) factors remains still relevant. Environmental factors may have a role in influencing the genetic predisposition for femoral vascular hypertrophy.

Pulse wave velocity and cardiac autonomic function in type 2 diabetes mellitus

BACKGROUND

Increased carotid-femoral pulse wave velocity (PWV) has been associated with incident cardiovascular disease, independently of traditional risk factors. Cardiac autonomic dysfunction is a common complication of diabetes and has been associated with reduced aortic distensibility. However, the association of cardiac autonomic dysfunction with PWV is not known. In this study we examined the association between cardiac autonomic function and PWV in subjects with type 2 diabetes mellitus.

METHODS

A total of 290 patients with type 2 diabetes were examined. PWV was measured at the carotid-femoral segment with applanation tonometry. Central mean arterial blood pressure (MBP) was determined by the same apparatus. Participants were classified as having normal (n = 193) or abnormal (n = 97) PWV values using age-corrected values. Cardiac autonomic nervous system activity was determined by measurement of parameters of heart rate variability (HRV).

RESULTS

Subjects with abnormal PWV were older, had higher arterial blood pressure and higher heart rate than those with normal PWV. Most of the values of HRV were significantly lower in subjects with abnormal than in those with normal PWV. Multivariate analysis, after controlling for various confounding factors, demonstrated that abnormal PWV was associated independently only with peripheral MBP [odds ratio (OR) 1.049, 95% confidence intervals (CI) 1.015-1.085, P = 0.005], central MBP (OR 1.052, 95% CI 1.016-1.088, P = 0.004), log total power (OR 0.490, 95% CI 0.258-0.932, P = 0.030) and log high frequency power (OR 0.546, 95% CI 0.301-0.991, P = 0.047).

CONCLUSIONS

In subjects with type 2 diabetes, arterial blood pressure and impaired cardiac autonomic function is associated independently with abnormal PWV.

Association between Lumbar Bone Mineral Density and Carotid Intima-Media Thickness in Korean Adults: a Cross-sectional Study of Healthy Twin Study

Bone mineral density (BMD) has been suggested to be associated with atherosclerosis. In the present study, we evaluated the association between lumbar BMD and the segments of carotid intima-media thickness (CIMT), a surrogate marker of subclinical atherosclerosis, in Korean adults, with consideration of sex and menopause status. Among 1,679 Korean adults who enrolled in a Healthy Twin Study, 723 men, 690 premenopausal women, and 266 postmenopausal women measured the CIMT at the common carotid artery intima-media thickness (CCA-IMT), carotid bifurcation intima-media thickness (BIF-IMT), internal carotid artery intima-media thickness (ICA-IMT) using B-mode ultrasound and lumbar BMD using dual-energy X-ray absorptiometry. The composite CIMT was calculated as the mean value of three CIMTs. The association was evaluated using linear mixed models. In premenopausal women, lumbar BMD was positively associated with composite CIMT and with CCA-IMT (P = 0.008 and 0.002, respectively). However, no association was observed between BMD and CIMT in men or in postmenopausal women. Stratified analysis revealed the effect of body mass index (BMI) on the association between BMD and CIME. The positive association in premenopausal women persisted only in low BMI (< 25 kg/m²) group, whereas a positive association appeared at high BMI (≥ 25 kg/m²) group in men. A high lumbar BMD may indicate an elevated risk of subclinical atherosclerosis in premenopausal women and men with high BMI.

Increased Aortic Calcification Is Associated With Arterial Stiffness Progression in Multiethnic Middle-Aged Men

Arterial stiffness is established as an independent predictor of cardiovascular morbidity and mortality. The objective was to prospectively evaluate association of aortic calcification burden with progression of arterial stiffness in population-based samples of healthy middle-aged men from ERA JUMP cohort (Electron-Beam Computed Tomography and Risk Factor Assessment in Japanese and US Men in the Post-World War II Birth Cohort). Men (n=635) aged 40 to 49 years (207 white American, 45 black American, 142 Japanese American, and 241 Japanese in Japan) were examined at baseline and 4 to 7 years later. Aortic calcification was evaluated from level of aortic arch to iliac bifurcation. Arterial stiffness progression was measured as annual change in brachial-ankle pulse wave velocity. Multivariable-adjusted general linear models were applied to investigate associations of longitudinal change in aortic calcification with arterial stiffness progression in participants overall, as well as in subgroups without or with prevalent aortic calcification at baseline. Annual change in aortic calcification was positively and significantly associated with arterial stiffness progression. In participants with annual changes in aortic calcium score of ≤0, 1 to 10, 11 to 100, and >100, the adjusted means (SD) for the annual change in brachial-ankle pulse wave velocity were 3.8 (2.2), 7.2 (2.2), 12.2 (1.8), and 15.6 (2.6) cm/s, respectively (P for trend <0.01) adjusted for baseline aortic calcification, arterial stiffness, and standard cardiovascular risk factors. Arterial stiffness was associated with the incidence of aortic calcification over the follow-up period among participants without aortic calcification (n=297) and with an increase in aortic calcification among participants with prevalent aortic calcification at baseline (n=388). Our findings suggest aortic calcification may be causally linked to arterial stiffness.

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

Supplemental Digital Content is available in the text

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 [β = −0.359, standard error (SE) = 0.07, P = 4.8 × 10^–8]. The same variant was also associated with increased CIB2 expression in leucocytes (β = 0.034, SE = 0.008, P = 4.95 × 10^–5) and skin (β = 0.072, SE = 0.01, P = 2.35 × 10^–9) and with hypomethylation of the gene promoter (β = −0.899, SE = 0.098, P = 3.63 × 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.

Arterial Stiffness and Central Hemodynamics in Thyroidectomized Patients on Long-Term Substitution Therapy with Levothyroxine

BACKGROUND

Long-term levothyroxine (LT4) therapy targeting thyrotropin (TSH) suppression in hypothyroid patients treated for thyroid cancer has been associated with increased arterial stiffness and increased cardiovascular mortality. However, most patients with hypothyroidism receive LT4 therapy targeting TSH in the reference range. The long-term vascular effects of this strategy have never been evaluated.

METHODS

Arterial stiffness and central hemodynamics were studied in 30 thyroidectomized patients (Mage = 54.5 ± 10.2 years; 80% female) on long-term (median = 11 years; range 3-41 years) LT4 replacement therapy targeting TSH in the reference range and 30 sex- and age-matched controls. Arterial stiffness was evaluated by carotid-femoral pulse wave velocity (PWV) and central hemodynamics by pulse wave analysis using the SphygmoCor system.

RESULTS

TSH levels were comparable in patients and controls (median = 1.99 × 10(3) IU/L [range 0.24-5.64 × 10(3) IU/L] vs. median = 2.13 × 10(3) IU/L [range 0.59-5.63 × 10(3) IU/L]; p = 0.69), but patients had higher plasma thyroxine and lower plasma triiodothyronine levels than controls (median = 108 nmol/L [range 84-149 nmol/L] vs. 86 nmol/L [range 59-141 nmol/L]; p < 0.001 and median = 1.49 nmol/L [range 1.00-2.37 nmol/L] vs. 1.62 nmol/L [range 1.18-2.09 nmol/L]; p = 0.04, respectively). PWV was not significantly higher in patients compared to controls (8.2 ± 1.9 vs. 7.9 ± 1.9 m/s, p = 0.69). Similarly, no group differences were observed in central systolic/diastolic blood pressure (120 ± 16 mmHg vs. 119 ± 12 mmHg, p = 0.77; and 80 ± 11 mmHg vs. 80 ± 10 mmHg, p = 0.98, respectively), the augmentation index (28 ± 13% vs. 29 ± 8%, p = 0.72), or the pulse pressure amplification ratio (129 ± 17% vs. 124 ± 13%, p = 0.18).

CONCLUSION

Despite subtle differences in plasma levels of thyroid hormones, long-term LT4 replacement therapy targeting TSH in the reference range does not seem to cause adverse effects on arterial stiffness and central hemodynamics.

Abdominal aortic calcification: A reappraisal of epidemiological and pathophysiological data

In men and women, there is a significant association between the risk of cardiovascular event (myocardial infarction, stroke) and risk of major fragility fracture (hip, vertebra). Abdominal aortic calcification (AAC) can be assessed using semiquantitative scores on spine radiographs and spine scans obtained by DXA. Severe AAC is associated with higher risk of major cardiovascular event. Not only does severe AAC reflect poor cardiovascular health status, but also directly disturbs blood flow in the vascular system. Severe (but not mild or moderate) AAC is associated with lower bone mineral density (BMD), faster bone loss and higher risk of major fragility fracture. The fracture risk remains increased after adjustment for BMD and other potential risk factors. The association between severe AAC and fracture risk was found in both sexes, mainly in the follow-ups of less than 10years. Many factors contribute to initiation and progression of AAC: lifestyle, co-morbidities, inorganic ions, dyslipidemia, hormones, cytokines (e.g. inflammatory cytokines, RANKL), matrix vesicles, microRNAs, structural proteins (e.g. elastin), vitamin K-dependent proteins, and medications (e.g. vitamin K antagonists). Osteogenic transdifferentiation of vascular smooth muscle cells (VSMC) and circulating osteoprogenitors penetrating into vascular wall plays a major role in the AAC initiation and progression. Vitamin K-dependent proteins protect vascular tunica media against formation of calcified deposits (matrix GLA protein, GLA-rich protein) and against VSMC apoptosis (Gas6). Further studies are needed to investigate clinical utility of AAC for the assessment of fracture and cardiovascular risk at the individual level and develop new medications permitting to prevent AAC progression.

Circulating concentrations of vitamin E isomers: Association with bone turnover and arterial stiffness in post-menopausal women

The effects of vitamin E on cardiovascular and bone health are conflicting with beneficial and detrimental findings reported. To investigate this further, we carried out a cross-sectional study to determine the relationship between circulating concentrations of the 2 vitamin E isomers, α- and γ-tocopherol (TP) with bone turnover and arterial stiffness. Two hundred and seventy eight post-menopausal women with mean age [SD] 60.9 [6.0] years were studied. Fasting serum α-TP and γ-TP, bone turnover markers; procollagen type 1 amino-terminal propeptide (P1NP) and C-terminal telopeptide of type 1 collagen (CTX), parathyroid hormone (PTH), total cholesterol (TC) and triglycerides (TG) were measured. Pulse wave velocity (PWV) and central augmentation index (AI) as markers of arterial stiffness were also determined. A positive correlation was observed between α-TP and γ-TP (r=0.14, p=0.022). A significant negative association between α-TP and P1NP only was seen in multiple linear regression analysis following adjustment for serum TC and TG (p=0.016). In a full multi-linear regression model, following correction for age, years since menopause, smoking habits, alcohol intake, use of calcium supplements, BMI, PTH, serum calcium, and estimated glomerular filtration rate (eGFR), the association between α-TP and P1NP remained significant (p=0.011). We did not observe any significant association between γ-TP or α-TP/γ-TP ratio with P1NP or CTX. P1NP was significantly lower in subjects with α-TP concentrations of >30 μmol/L (α-TP >30 μmol/L; P1NP: 57.5 [20.7], α-TP<30 μmol/L; P1NP: 65.7 [24.9] μg/L, p=0.005). PWV was significantly associated with α-TP/γ-TP ratio (p=0.04) but not with serum α-TP or γ-TP in a full multi-linear regression model adjusting for serum lipids, age, and blood pressure. The data suggest that high serum concentrations of α-TP may have a negative effect on bone formation. The balance of α-TP and γ-TP may be important in maintaining arterial compliance. Longitudinal studies are needed to investigate the impact of the vitamin E isomers on bone and cardiovascular health.

Association of Cross-Sectional and Longitudinal Change in Arterial Stiffness With Gene Expression in the Twins UK Cohort

We investigated whether expression of genes previously implicated in arterial stiffening associates with cross-sectional and longitudinal measures of arterial stiffness. Women from the Twins UK cohort (n=470, aged 39-81 years) had gene expression in lymphoblastoid cell lines measured using an Illumina microarray. Arterial stiffness was measured by carotid-femoral pulse wave velocity and carotid distensibility. A subsample (n=121) of women had repeat vascular measures after a mean±SD follow-up of 4.3±1.4 years. Associations of arterial phenotypes with gene expression levels were examined for 52 genes identified from previous association studies. The gene transcript most closely associated with pulse wave velocity in cross-sectional analysis was ectonucleotide pyrophosphatase/phosphodiesterase (P=0.012). Pleiotropic genetic effects accounted for 14% of the phenotypic correlation between ectonucleotide pyrophosphatase/phosphodiesterase expression and pulse wave velocity. Progression of pulse wave velocity during the follow-up period best related to expression of ectonucleotide pyrophosphatase/phosphodiesterase (β=0.19, P=0.008) and collagen type IV α 1 (β=0.32, P<0.0001). Gene transcripts most closely related to change in carotid distensibility during the follow-up period were endothelial nitric oxide synthase (β=-0.20, P=0.005), angiotensin-converting enzyme (β=-0.15, P=0.035), and B-cell CLL/lymphoma11B (β=0.18, P=0.010). Expression levels of angiotensin-converting enzyme also related to progression in carotid diameter (β=0.21, P=0.012). Expression levels of ectonucleotide pyrophosphatase/phosphodiesterase, involved in arterial calcification, and collagen type IV α 1, involved in collagen formation, correlate with aortic stiffening. These genes may be functional mediators of arterial stiffening.

Pharmacogenomics of estrogens on changes in carotid artery intima-medial thickness and coronary arterial calcification: Kronos Early Estrogen Prevention Study

Prior to the initiation of menopausal hormone treatment (MHT), genetic variations in the innate immunity pathway were found to be associated with carotid artery intima-medial thickness (CIMT) and coronary arterial calcification (CAC) in women (n = 606) enrolled in the Kronos Early Estrogen Prevention Study (KEEPS). Whether MHT might affect these associations is unknown. The association of treatment outcomes with variation in the same 764 candidate genes was evaluated in the same KEEPS participants 4 yr after randomization to either oral conjugated equine estrogens (0.45 mg/day), transdermal 17β-estradiol (50 μg/day), each with progesterone (200 mg/day) for 12 days each month, or placebo pills and patch. Twenty SNPs within the innate immunity pathway most related with CIMT after 4 yr were not among those associated with CIMT prior to MHT. In 403 women who completed the study in their assigned treatment group, single nucleotide polymorphisms (SNPs) within the innate immunity pathway were found to alter the treatment effect on 4 yr change in CIMT (i.e., significant interaction between treatment and genetic variation in the innate immunity pathway; P < 0.001). No SNPs by treatment effects were observed with changes of CAC >5 Agatston units after 4 yr. Results of this study suggest that hormonal status may interact with genetic variants to influence cardiovascular phenotypes, specifically, the pharmacogenomic effects within the innate immunity pathway for CIMT.

Rationale, Design, and Methodological Aspects of the BUDAPEST-GLOBAL Study (Burden of Atherosclerotic Plaques Study in Twins-Genetic Loci and the Burden of Atherosclerotic Lesions)

The heritability of coronary atherosclerotic plaque burden, coronary geometry, and phenotypes associated with increased cardiometabolic risk are largely unknown. The primary aim of the Burden of Atherosclerotic Plaques Study in Twins-Genetic Loci and the Burden of Atherosclerotic Lesions (BUDAPEST-GLOBAL) study is to evaluate the influence of genetic and environmental factors on the burden of coronary artery disease. By design this is a prospective, single-center, classical twin study. In total, 202 twins (61 monozygotic pairs, 40 dizygotic same-sex pairs) were enrolled from the Hungarian Twin Registry database. All twins underwent non-contrast-enhanced computed tomography (CT) for the detection and quantification of coronary artery calcium and for the measurement of epicardial fat volumes. In addition, a single non-contrast-enhanced image slice was acquired at the level of L3-L4 to assess abdominal fat distribution. Coronary CT angiography was used for the detection and quantification of plaque, stenosis, and overall coronary artery disease burden. For the primary analysis, we will assess the presence and volume of atherosclerotic plaques. Furthermore, the 3-dimensional coronary geometry will be assessed based on the coronary CT angiography datasets. Additional phenotypic analyses will include per-patient epicardial and abdominal fat quantity measurements. Measurements obtained from monozygotic and dizygotic twin pairs will be compared to evaluate the genetic or environmental effects of the given phenotype. The BUDAPEST-GLOBAL study provides a unique framework to shed some light on the genetic and environmental influences of cardiometabolic disorders.

Amino Acid Intakes Are Inversely Associated with Arterial Stiffness and Central Blood Pressure in Women

BACKGROUND

Although data suggest that intakes of total protein and specific amino acids (AAs) reduce blood pressure, data on other cardiovascular disease risk factors are limited.

OBJECTIVE

We examined associations between intakes of AAs with known mechanistic links to cardiovascular health and direct measures of arterial stiffness, central blood pressure, and atherosclerosis.

METHODS

In a cross-sectional study of 1898 female twins aged 18-75 y from the TwinsUK registry, intakes of 7 cardioprotective AAs (arginine, cysteine, glutamic acid, glycine, histidine, leucine, and tyrosine) were calculated from food-frequency questionnaires. Direct measures of arterial stiffness and atherosclerosis included central systolic blood pressure (cSBP), mean arterial pressure (MAP), augmentation index (AI), pulse wave velocity (PWV), and intima-media thickness (IMT). ANCOVA was used to assess the associations between endpoints of arterial stiffness and intake (per quintile), adjusting for potential confounders.

RESULTS

In multivariable analyses, higher intakes of total protein and 7 potentially cardioprotective AAs were associated with lower cSBP, MAP, and PWV. Higher intakes of glutamic acid, leucine, and tyrosine were most strongly associated with PWV, with respective differences of -0.4 ± 0.2 m/s (P-trend = 0.02), -0.4 ± 0.2 m/s (P-trend = 0.03), and -0.4 ± 0.2 m/s (P-trend = 0.03), comparing extreme quintiles. There was a significant interaction between AA intakes and protein source, and higher intakes of AAs from vegetable sources were associated with lower central blood pressure and AI. Higher intakes of glutamic acid, leucine, and tyrosine from animal sources were associated with lower PWV.

CONCLUSIONS

These data provide evidence to suggest that intakes of several AAs are associated with cardiovascular benefits beyond blood pressure reduction in healthy women. The magnitude of the observed associations was similar to those previously reported for other lifestyle factors. Increasing intakes of these AAs could be an important and readily achievable way to reduce cardiovascular disease risk.