Genetic loci associated with nonobstructive coronary artery disease in Caucasian women

Coronary microcirculation in myocardial ischemia: A genetic perspective

Coronary microvascular dysfunction (CMD) is a major contributor to ischemic heart disease (IHD), acting both independently and together with atherosclerosis. CMD encompasses structural and functional microcirculatory changes that result in dysregulated coronary blood flow. Structural abnormalities include microvascular remodeling, resulting in arteriolar and capillary narrowing, perivascular fibrosis and capillary rarefaction. Endothelial dysfunction and smooth muscle cell hyperactivity further impair microcirculation. Genetic factors may play a crucial role in the pathophysiology of CMD, mainly due to single nucleotide polymorphisms (SNPs) in genes that regulate coronary blood flow and microcirculation structural modifications. This manuscript aims to review the genetic determinants of CMD, with particular focus on ion channels, microRNAs (miRNAs), and proteins involved in the endothelial environment. The improving knowledge about genetic aspects of CMD opens the possibility to have new biomarkers, improving diagnosis and the development of targeted treatments in light of an even more patient-tailored approach.

Emerging Pathway to a Precision Medicine Approach for Angina With Nonobstructive Coronary Arteries in Women

Women are disproportionately affected by symptoms of angina with nonobstructive coronary arteries (ANOCA) which is associated with significant mortality and economic impact. Although distinct endotypes of ANOCA have been defined, it is underdiagnosed and is often incompletely characterized when identified. Patients are often unresponsive to traditional therapeutic options, which are typically antianginal, and the current ability to guide treatment modification by specific pathways is limited. Studies have associated specific genetic loci, transcriptomic features, and biomarkers with ANOCA. Such panomic data, in combination with known imaging and invasive diagnostic techniques, should be utilized to define more precise pathophysiologic subtypes of ANOCA in women, which will in turn help to identify targeted, effective therapies. A precision medicine-based approach to managing ANOCA incorporating these techniques in women has the potential to significantly improve their clinical care.

Single Nucleotide Polymorphisms in Coronary Microvascular Dysfunction

Coronary microvascular dysfunction is an underdiagnosed pathologic process that is associated with adverse clinical outcomes. There are data to suggest that coronary microvascular dysfunction, in some cases, may be genetically determined. We present an updated review of single nucleotide polymorphisms in coronary microvascular dysfunction.

The Protective Effect of Polymorphisms rs2681472 and rs17249754 of the ATP2B1 Gene Against Coronary Artery Disease and Hypertension is Abolished by Tobacco Smoking

Aim    To study the relationship of single nucleotide polymorphisms rs2681472 and rs17249754 in the ATP2B1 gene with risk of ischemic heart disease (IHD) and arterial hypertension (AH) among residents of Central Russia and to evaluate the trigger role of smoking as a risk factor for development of IHD and AH in carriers of ATP2B1 gene polymorphic variants.Material and methods    The study included DNA samples from 1960 residents of Central Russia of Slavic origin. Among them, there were 1261 patients with cardiovascular diseases and 699 healthy persons. The vast majority of patients had both IHD and AH. Genotyping was performed using the iPLEX technique on a MassARRAY-4 genomic mass-spectrometer. The relationship of ATP2B1 alleles, genotypes, and haplotypes with the risk of diseases was calculated by logistic regression analysis with adjustments for sex and age.Results    Carriage of AG and GG (rs2681472) genotypes and GA (rs17249754) genotype was associated with a reduced risk of both IHD (p=0.0057 and p=0.022 for rs2681472 and rs17249754, respectively) and AH (p=0.016 and p=0.036, respectively). Rare rs2681472G-rs17249754G and rs2681472A-rs17249754A haplotypes were associated with a reduced risk of IHD (odds ratio, OR, 0.22; 95 % CI: 0.11-0.46, p=0.0001) and AH (OR, 0.22; 95 % CI: 0.10-0.47, p=0.0001). Analysis of the groups stratified by the smoking status showed that in smokers, the studied polymorphic variants did not have a protective action with respect of either IHD or AH. However, in non-smokers, the genotypes AG and GG rs2681472 (OR, 0.62; 95 % CI: 0.47-0.80, p=0.0004) and GA rs17249754 (OR, 0.61; 95 % CI: 0.47-0.81, p=0.0004) were associated with a reduced risk of IHD and AH (OR, 0.63; 95 % CI: 0.48-0.83, p=0.0004 for rs2681472; OR, 0.63; 95 % CI: 0.48-0.83, p=0.001 for rs17249754), as well as the carriage of the minor alleles rs2681472‑G and rs17249754‑A.Conclusion    It was shown for the first time that the polymorphic variants rs17249754 and rs2681472 of the ATP2B1 gene are associated with a reduced risk for IHD and AH only in non-smokers.

DNA methylation signature in blood mirrors successful weight-loss during lifestyle interventions: the CENTRAL trial

BACKGROUND

One of the major challenges in obesity treatment is to explain the high variability in the individual's response to specific dietary and physical activity interventions. With this study, we tested the hypothesis that specific DNA methylation changes reflect individual responsiveness to lifestyle intervention and may serve as epigenetic predictors for a successful weight-loss.

METHODS

We conducted an explorative genome-wide DNA methylation analysis in blood samples from 120 subjects (90% men, mean ± SD age = 49 ± 9 years, body mass-index (BMI) = 30.2 ± 3.3 kg/m2) from the 18-month CENTRAL randomized controlled trial who underwent either Mediterranean/low-carbohydrate or low-fat diet with or without physical activity.

RESULTS

Analyses comparing male subjects with the most prominent body weight-loss (responders, mean weight change - 16%) vs. non-responders (+ 2.4%) (N = 10 each) revealed significant variation in DNA methylation of several genes including LRRC27, CRISP2, and SLFN12 (all adj. P < 1 × 10-5). Gene ontology analysis indicated that biological processes such as cell adhesion and molecular functions such as calcium ion binding could have an important role in determining the success of interventional therapies in obesity. Epigenome-wide association for relative weight-loss (%) identified 15 CpGs being negatively correlated with weight change after intervention (all combined P < 1 × 10- 4) including new and also known obesity candidates such as NUDT3 and NCOR2. A baseline DNA methylation score better predicted successful weight-loss [area under the curve (AUC) receiver operating characteristic (ROC) = 0.95-1.0] than predictors such as age and BMI (AUC ROC = 0.56).

CONCLUSIONS

Body weight-loss following 18-month lifestyle intervention is associated with specific methylation signatures. Moreover, methylation differences in the identified genes could serve as prognostic biomarkers to predict a successful weight-loss therapy and thus contribute to advances in patient-tailored obesity treatment.

Even "WISE-R?"-an Update on the NHLBI-Sponsored Women's Ischemia Syndrome Evaluation

PURPOSE OF REVIEW

For over 20 years, the Women's Ischemia Syndrome Evaluation (WISE), a program sponsored by the National Heart, Lung, and Blood Institute, has explored diverse and important aspects of ischemic heart disease in women.

RECENT FINDINGS

Women with symptoms and signs of ischemia but no significant epicardial obstructive coronary artery disease (INOCA) were documented to be at elevated risk for recurrent angina hospitalization, major adverse cardiac events, death, and health resource consumption rivaling those with obstructive coronary disease. WISE investigators have advanced our understanding of cardiovascular outcomes, systemic manifestations, psychological variables, socioeconomic factors, genetic contributions, hormonal status, advanced imaging, coronary functional findings, biomarkers, patient-reported outcomes, and treatments pertaining to women with this disease entity. This review delves into the WISE findings subsequent to a prior review1, postulates directions for future research, and asks are we "Even 'WISE-R?'".

Predicted Versus Observed Major Adverse Cardiac Event Risk in Women With Evidence of Ischemia and No Obstructive Coronary Artery Disease: A Report From WISE (Women's Ischemia Syndrome Evaluation)

Background Primary prevention risk scores are commonly used to predict cardiovascular (CVD) outcomes. The applicability of these scores in patients with evidence of myocardial ischemia but no obstructive coronary artery disease is unclear. Methods and Results Among 935 women with signs and symptoms of ischemia enrolled in WISE (Women's Ischemia Syndrome Evaluation), 567 had no obstructive coronary artery disease on angiography. Of these, 433 had had available risk data for 6 commonly used scores: Framingham Risk Score, Reynolds Risk Score, Adult Treatment Panel III, Atherosclerotic Cardiovascular Disease, Systematic Coronary Risk Evaluation, Cardiovascular Risk Score 2. Score-specific CVD rates were assessed. For each score, we evaluated predicted versus observed event rates at 10-year follow-up using c statistic. Recalibration was done for 3 of the 6 scores. The 433 women had a mean age of 56.9±9.4 years, 82.5% were white, 52.7% had hypertension, 43.6% had dyslipidemia, and 16.9% had diabetes mellitus. The observed 10-year score-specific CVD rates varied between 5.54% (Systematic Coronary Risk Evaluation) to 28.87% (Framingham Risk Score), whereas predicted event rates varied from 1.86% (Systematic Coronary Risk Evaluation) to 6.99% (Cardiovascular Risk Score 2). The majority of scores showed moderate discrimination (c statistic 0.53 for Atherosclerotic Cardiovascular Disease and Systematic Coronary Risk Evaluation; 0.78 for Framingham Risk Score) and underestimated risk (statistical discordance -58% for Adult Treatment Panel III; -84% for Atherosclerotic Cardiovascular Disease). Recalibrated Reynolds Risk Score, Atherosclerotic Cardiovascular Disease, and Framingham Risk Score had improved performance, but significant underestimation remained. Conclusions Commonly used CVD risk scores fail to accurately predict CVD rates in women with ischemia and no obstructive coronary artery disease. These results emphasize the need for new risk assessment scores to reliably assess this population.

Powerful and efficient SNP-set association tests across multiple phenotypes using GWAS summary data

MOTIVATION

Many GWAS conducted in the past decade have identified tens of thousands of disease related variants, which in total explained only part of the heritability for most traits. There remain many more genetics variants with small effect sizes to be discovered. This has motivated the development of sequencing studies with larger sample sizes and increased resolution of genotyped variants, e.g., the ongoing NHLBI Trans-Omics for Precision Medicine (TOPMed) whole genome sequencing project. An alternative approach is the development of novel and more powerful statistical methods. The current dominating approach in the field of GWAS analysis is the "single trait single variant" association test, despite the fact that most GWAS are conducted in deeply-phenotyped cohorts with many correlated traits measured. In this paper, we aim to develop rigorous methods that integrate multiple correlated traits and multiple variants to improve the power to detect novel variants. In recognition of the difficulty of accessing raw genotype and phenotype data due to privacy and logistic concerns, we develop methods that are applicable to publicly available GWAS summary data.

RESULTS

We build rigorous statistical models for GWAS summary statistics to motivate novel multi-trait SNP-set association tests, including variance component test, burden test and their adaptive test, and develop efficient numerical algorithms to quickly compute their analytical P-values. We implement the proposed methods in an open source R package. We conduct thorough simulation studies to verify the proposed methods rigorously control type I errors at the genome-wide significance level, and further demonstrate their utility via comprehensive analysis of GWAS summary data for multiple lipids traits and glycemic traits. We identified many novel loci that were not detected by the individual trait based GWAS analysis.

AVAILABILITY AND IMPLEMENTATION

We have implemented the proposed methods in an R package freely available at http://www.github.com/baolinwu/MSKAT.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

The Kronos Early Estrogen Prevention Study (KEEPS): what have we learned?

OBJECTIVE

The Kronos Early Estrogen Prevention Study (KEEPS) was designed to address gaps in understanding the effects of timely menopausal hormone treatments (HT) on cardiovascular health and other effects of menopause after the premature termination of the Women's Health Initiative.

METHOD

The KEEPS was a randomized, double-blinded, placebo-controlled trial to test the hypothesis that initiation of HT (oral conjugated equine estrogens [o-CEE] or transdermal 17β-estradiol [t-E2]) in healthy, recently postmenopausal women (n = 727) would slow the progression of atherosclerosis as measured by changes in carotid artery intima-media thickness (CIMT).

RESULTS

After 4 years, neither HT affected the rate of increase in CIMT. There was a trend for reduced accumulation of coronary artery calcium with o-CEE. There were no severe adverse effects, including venous thrombosis. Several ancillary studies demonstrated a positive effect on mood with o-CEE, and reduced hot flashes, improved sleep, and maintenance of bone mineral density with both treatments. Sexual function improved with t-E2. There were no significant effects of either treatment on cognition, breast pain, or skin wrinkling. Variants of genes associated with estrogen metabolism influenced the age of menopause and variability in effects of the HT on CIMT. Platelet activation associated with the development of white matter hyperintensities in the brain.

CONCLUSIONS

KEEPS and its ancillary studies have supported the value and safety of the use of HT in recently postmenopausal women and provide a perspective for future research to optimize HT and health of postmenopausal women. The KEEPS continuation study continues to pursue these issues.

Association of ATP2B1 common variants with asymptomatic intracranial and extracranial large artery stenosis in hypertension patients

BACKGROUND AND AIMS

Genetic factors play an important role in the cervico-cerebral large-artery atherosclerotic stenosis (LAS), and ATP2B1 gene has been associated with the process of atherosclerosis disorders, such as coronary artery disease and arterial stiffness. But there is little information about the relationship between ATP2B1 gene and atherosclerosis in the intracranial arteries. We hereby investigated the association of common variants in ATP2B1 gene with LAS in asymptomatic Chinese hypertension patients.

METHODS

The stenosis of intracranial and extracranial arteries were evaluated in 899 subjects through computerized tomography angiography from the aortic arch to the skull base. A total of 11 ATP2B1 common variants were genotyped. Multivariate logistic regression was carried out in a dominant model with confounding factors adjusted.

RESULTS

rs17249754-A (OR = 0.43, p = 0.0002) and rs1401982-G (OR = 0.47, p = 0.0007) were associated with decreased susceptibility of concurrent extra and intracranial stenosis even after Bonferroni correction. These two minor alleles were also significantly associated with less stenotic arteries and moderate-to-severe stenosis.

CONCLUSION

rs17249754 and rs1401982 were associated with asymptomatic LAS in stroke-free Chinese hypertension patients and might benefit early recognition of LAS patients in clinical practice.

Identification of novel alleles associated with insulin resistance in childhood obesity using pooled-DNA genome-wide association study approach

Background:

Recently, we witnessed great progress in the discovery of genetic variants associated with obesity and type 2 diabetes (T2D), especially in adults. Much less is known regarding genetic variants associated with insulin resistance (IR). We hypothesized that novel IR genes could be efficiently detected in a population of obese children and adolescents who may not exhibit comorbidities and other confounding factors.

Objectives:

This study aimed to determine whether a genome-wide association study (GWAS), using a DNA-pooling approach, could identify novel genes associated with IR.

Subjects:

The pooled-DNA GWAS analysis included Slovenian obese children and adolescents with and without IR matched for body mass index, gender and age. A replication study was conducted in another independent cohort with or without IR.

Methods:

For the pooled-DNA GWAS, we used HumanOmni5-Quad SNP array (Illumina). Allele frequency distributions were compared with modified t-tests and χ²-tests and ranked using PLINK. Top single nucleotide polymorphisms (SNPs) were validated using individual genotyping by high-resolution melting analysis and TaqMan assay.

Results:

We identified five top-ranking SNPs from the pooled-DNA GWAS analysis within the ECE1, IL1R2, GNPDA1, HLA-J and PYGB loci. All except SNP rs9261108 (HLA-J locus) were confirmed in the validation phase using individual genotyping. The SNP rs2258617 within PYGB remained statistically significant for both recessive and additive models in both cohorts and in a merged analysis of both cohorts and present the strongest novel candidate gene for IR.

Conclusion:

We report for the first time a pooled-DNA GWAS approach to identify five novel SNPs or genes for IR in a paediatric population. The four loci confirmed in the second validation phase study warrant further studies, especially the strongest SNP rs2258617 within PYGB, and provide targets for further basic research of IR mechanisms and for the development of potential new IR and T2D therapies.

The Plasma Membrane Calcium ATPases and Their Role as Major New Players in Human Disease

The Ca²⁺ extrusion function of the four mammalian isoforms of the plasma membrane calcium ATPases (PMCAs) is well established. There is also ever-increasing detail known of their roles in global and local Ca²⁺ homeostasis and intracellular Ca²⁺ signaling in a wide variety of cell types and tissues. It is becoming clear that the spatiotemporal patterns of expression of the PMCAs and the fact that their abundances and relative expression levels vary from cell type to cell type both reflect and impact on their specific functions in these cells. Over recent years it has become increasingly apparent that these genes have potentially significant roles in human health and disease, with PMCAs1-4 being associated with cardiovascular diseases, deafness, autism, ataxia, adenoma, and malarial resistance. This review will bring together evidence of the variety of tissue-specific functions of PMCAs and will highlight the roles these genes play in regulating normal physiological functions and the considerable impact the genes have on human disease.

Genetic Research and Women's Heart Disease: a Primer

PURPOSE OF REVIEW

This review provides a brief synopsis of sexual dimorphism in atherosclerosis with an emphasis on genetic studies aimed to better understand the atherosclerotic process and clinical outcomes in women. Such studies are warranted because development of atherosclerosis, impact of several traditional risk factors, and burden of coronary heart disease (CHD) differ between women and men.

RECENT FINDINGS

While most candidate gene studies pool women and men and adjust for sex, some sex-specific studies provide evidence of association between candidate genes and prevalent and incident CHD in women. So far, most genome-wide association studies (GWAS) also failed to consider sex-specific associations. The few GWAS focused on women tended to have small sample sizes and insufficient power to reject the null hypothesis of no association even if associations exist. Few studies consider that sex can modify the effect of gene variants on CHD. Sufficiently large-scale genetic studies in women of different race/ethnic groups, taking into account possible gene-gene and gene-environment interactions as well as hormone-mediated epigenetic mechanisms, are needed. Using the same disease definition for women and men might not be appropriate. Accurate phenotyping and inclusion of relevant outcomes in women, together with targeting the entire spectrum of atherosclerosis, could help address the contribution of genes to sexual dimorphism in atherosclerosis. Discovered genetic loci should be taken forward for replication and functional studies to elucidate the plausible underlying biological mechanisms. A better understanding of the etiology of atherosclerosis in women would facilitate future prevention efforts and interventions.