Genetics of coronary artery disease in the post-GWAS era

Genome-wide allele-specific expression in multi-tissue samples from healthy male baboons reveals the transcriptional complexity of mammals

Allele-specific expression (ASE) is pivotal in understanding the genetic underpinnings of phenotypic variation within species, differences in disease susceptibility, and responses to environmental factors. We processed 11 different tissue types collected from 12 age-matched healthy olive baboons (Papio anubis) for genome-wide ASE analysis. By sequencing their genomes at a minimum depth of 30×, we identified over 16 million single-nucleotide variants (SNVs). We also generated long-read sequencing data, enabling the phasing of all variants present within the coding regions of 96.5% of assayable protein-coding genes as a single haplotype block. Given the extensive heterozygosity of baboons relative to humans, we could quantify ASE across 72% of the total annotated protein-coding gene set. We identified genes that exhibit ASE and affect specific tissues and genotypes. We discovered ASE SNVs that also exist in human populations with identical alleles and that are designated as pathogenic by both the PrimateAI-3D and AlphaMissense models.

Clinical utility and implementation of polygenic risk scores for predicting cardiovascular disease: A clinical consensus statement of the ESC Council on Cardiovascular Genomics, the ESC Cardiovascular Risk Collaboration, and the European Association of Preventive Cardiology

Genome-wide association studies have revealed hundreds of genetic variants associated with cardiovascular diseases (CVD). Polygenic risk scores (PRS) can capture this information in a single metric and hold promise for use in CVD risk prediction. Importantly, PRS information can reflect the causally mediated risk to which the individual is exposed throughout life. Although European Society of Cardiology guidelines do not currently advocate their use in routine clinical practice, PRS are commercially available and increasingly sought by clinicians, health systems, and members of the public to inform personalized health care decision-making. This clinical consensus statement provides an overview of the scientific basis of PRS and evidence to date on their role in CVD risk prediction for the purposes of disease prevention. It provides the reader with a summary of the opportunities and challenges for implementation and identifies current gaps in supporting evidence. The document also lays out a potential roadmap by which the scientific and clinical community can navigate any future transition of PRS into routine clinical care. Finally, clinical scenarios are presented where information from PRS may hold most value and discuss organizational frameworks to enable responsible use of PRS testing while more evidence is being generated by clinical studies.

Translation of genomics into routine cardiological practice: insights from a European Society of Cardiology Cardiovascular Round Table

Cardiovascular diseases (CVD) remain the leading cause of death globally and there is an urgent need for innovative approaches to treatment. One emerging avenue is genetic therapies, which hold particular promise for diseases with a monogenic basis. Gene silencing techniques using antisense oligonucleotides or ribonucleic acid interference strategies are currently at the forefront of genetic therapies in CVD, with several ribonucleic acid-targeted therapies already approved for the treatment of conditions such as familial hypercholesterolaemia and transthyretin amyloidosis. For diseases caused by loss-of-function genetic variants, there is growing interest in gene therapy, applying either gene replacement strategies using adeno-associated virus vectors or gene editing strategies using tools such as the clustered regularly interspaced short palindromic repeats and clustered regularly interspaced short palindromic repeats-associated protein-9 system. Preclinical studies have highlighted the potential of this technology in CVD and promising data are beginning to emerge from early-phase clinical trials. During a European Society of Cardiology Cardiovascular Round Table workshop, the challenges of translating these novel therapeutic strategies to the routine cardiology clinic were discussed. Several key priorities were identified, including the need for disease-specific preclinical models, precision diagnostics, adequately powered clinical trials with meaningful endpoints, and enhanced education of healthcare professionals and patients. The Cardiovascular Round Table also considered the role of polygenic risk scores in risk stratification and how these can potentially be implemented in clinical practice.

Personalization of primary prevention: Exploring the role of coronary artery calcium and polygenic risk score in cardiovascular diseases

Personalized healthcare is becoming increasingly popular given the vast heterogeneity in disease manifestation between individuals. Many commonly encountered diseases within cardiology are multifactorial in nature and disease progression and response is often variable due to environmental and genetic factors influencing disease states. This makes accurate early identification and primary prevention difficult in certain populations, especially young patients with limited Atherosclerotic Cardiovascular Disease (ASCVD) risk factors. Newer strategies, such as coronary artery calcium (CAC) scans and polygenic risk scores (PRS), are being implemented to aid in the detection of subclinical disease and heritable risk, respectively. Data surrounding CAC scans have shown promising results in their ability to detect subclinical atherosclerosis and predict the risk of future coronary events, especially at the extremes; however, predictive variability exists among different patient populations, limiting the test's specificity. Furthermore, relying only on CAC scores and ASCVD risk scores may fail to identify a large group of patients needing primary prevention who lack subclinical disease and traditional risk factors, but harbor genetic variabilities strongly associated with certain cardiovascular diseases. PRS can overcome these limitations. These scores can be measured in individuals as early as birth to identify genetic variants placing them at elevated risk for developing cardiovascular disease, irrespective of their current cardiovascular health status. By applying PRS alongside CAC scores, previously overlooked patient populations can be identified and begin primary prevention strategies early to achieve optimal outcomes. In this review, we expand on the current knowledge surrounding CAC scores and PRS and highlight the future possibilities of these technologies for preventive cardiology.

[Role of genetics in precision medicine of coronary artery disease]

Coronary artery disease (CAD) develops multifactorially through an interplay of lifestyle, environmental and genetic factors. Smoking, hypertension, hyperlipidemia, obesity and diabetes mellitus are modifiable risk factors for CAD. In addition, both rare mutations and multiple frequently occurring genetic variants can cause CAD, whereby the heritability of CAD is ca. 50%. Genetic diagnostics enable the early identification of affected children and adults and, based on a greatly increased cardiovascular risk, initiation of preventive treatment. In recent years, genome-wide association studies have identified hundreds of significant variants that together greatly increase the risk of CAD. In the general population the many frequently occurring risk alleles in combination with modifiable risk factors result in a widespread genetic predisposition to CAD. Their relevance arises in the context of an integrative risk assessment, whereby the additional genetic risk can be calculated by polygenic risk scores (PRS), which provide a hazard ratio that can be multiplied with the clinically determined risk. This overview article discusses the diagnostic principles of rare and frequent genetic causes of CAD as well as their implications in the precision treatment of the disease.

Cell type-specific epigenetic regulatory circuitry of coronary artery disease loci

Coronary artery disease (CAD) is the leading cause of death worldwide. Recently, hundreds of genomic loci have been shown to increase CAD risk, however, the molecular mechanisms underlying signals from CAD risk loci remain largely unclear. We sought to pinpoint the candidate causal coding and non-coding genes of CAD risk loci in a cell type-specific fashion. We integrated the latest statistics of CAD genetics from over one million individuals with epigenetic data from 45 relevant cell types to identify genes whose regulation is affected by CAD-associated single nucleotide variants (SNVs) via epigenetic mechanisms. Applying two statistical approaches, we identified 1,580 genes likely involved in CAD, about half of which have not been associated with the disease so far. Enrichment analysis and phenome-wide association studies linked the novel candidate genes to disease-specific pathways and CAD risk factors, corroborating their disease relevance. We showed that CAD-SNVs are enriched to regulate gene expression by affecting the binding of transcription factors (TFs) with cellular specificity. Of all the candidate genes, 23.5% represented non-coding RNAs (ncRNA), which likewise showed strong cell type specificity. We conducted a proof-of-concept biological validation for the novel CAD ncRNA gene IQCH-AS1 . CRISPR/Cas9-based gene knockout of IQCH-AS1 , in a human preadipocyte strain, resulted in reduced preadipocyte proliferation, less adipocyte lipid accumulation, and atherogenic cytokine profile. The cellular data are in line with the reduction of IQCH-AS1 in adipose tissues of CAD patients and the negative impact of risk alleles on its expression, suggesting IQCH-AS1 to be protective for CAD. Our study not only pinpoints CAD candidate genes in a cell type-specific fashion but also spotlights the roles of the understudied ncRNA genes in CAD genetics.

Exploring sex-specific genetic architecture of coronary artery disease in Tehran: a cardiometabolic genetic study

BACKGROUND

The development of coronary artery disease (CAD) is influenced by sex and genetic factors. Genome-wide association studies (GWAS) have linked genetic loci to CAD, mostly in European populations. The study aims to find sex-related genetic differences in the Iranian population.

RESEARCH DESIGN AND METHODS

We conducted a sex-stratified GWAS with 4519 subjects (1832 males and 2687 females) in the discovery group and 922 subjects (495 males and 427 females) in the confirmation group of an Iranian cohort. We analyzed 9,141,124 variants using a genome-wide complex trait analysis (GCTA) tool.

RESULTS

We detected distinct genetic variants associated with CAD in males: rs34952209 [OR = 1.79; p = 5.216E-8], rs1432687863 [OR = 1.95; p = 8.477E-8], and in females, rs7314741 [OR = 1.67; p = 7.142-8E] positively influenced CAD risk. The CAD-associated SNPs that were obtained have been confirmed using independent samples. Rs3495229 May impact histone mark and Pou2f2 motifs, while rs7314741 in the LEM Domain Containing 3 (LEMD3) promoter may affect a regulatory motif for the STAT transcription factor. According to Roadmap and ENCODE data, Rs1432687863 is a new variant affecting CAD in males, potentially through H3K9me3 in the heart.

CONCLUSIONS

Our findings highlight the role of sex-specific genetic differences in CAD development, providing novel insights into disease pathways which is not appropriate using a sex-combined strategy. [Figure: see text].

Interplay between lifestyle factors and polygenic risk for incident coronary heart disease in a large multiethnic cohort

Introduction

The objective of this study was to examine the interplay of polygenic risk and individual lifestyle factors (and a composite score of lifestyle) as antecedents of CHD in a large multiethnic cohort.

Methods

We used Genetic Epidemiology Resource in Adult Health and Aging (GERA) cohort participants free of CHD at baseline (n = 60,568; 67 % female; 18 % non-European). The individual and joint associations of smoking, Mediterranean diet pattern, level of physical activity and polygenic risk with incident CHD were assessed using Cox regression adjusting for genetic ancestry and non-mediating risk factors. Hazard ratios (HRs) and number needed to treat (NNT) were estimated according to these lifestyle factors and polygenic risk categories. Strengths included large sample size, long-follow-up, ethnic diversity, a clinically-validated polygenic risk score (PRS), and rich phenotype information.

Results

After 14 years of follow-up, there were 3159 incident CHD events. We observed no statistically significant interactions between individual lifestyle factors and polygenic risk (all p > 0.23). For individuals with a high genetic risk, moving from the worse lifestyle combination (no favorable lifestyle factors) to the best lifestyle combination (all three) is associated with 52 % lower rate of CHD. The NNT was highest in the low polygenic risk group (34), lowest in the high polygenic risk group [19] and in-between (Jin et al., 2011) [24] in the intermediate polygenic risk group.

Conclusions

Lifestyle and polygenic risk together influence the risk of incident CHD. Our results support consideration of polygenic risk in lifestyle interventions because those with high polygenic risk are likely to derive the most benefit.

Genetic Polymorphism in miRNA Genes and Their Association with susceptibility of Coronary Heart Disease: An Updated Review

Coronary heart disease (CHD) remains a major public health concern worldwide, with a complex interplay of genetic, environmental and lifestyle factors contributing to its pathogenesis. The potential significance of microRNAs (miRNAs) in the onset and progression of CHD has attracted increasing attention in recent years. Small non-coding RNA molecules called miRNAs control gene expression at the post-transcriptional level. Dysregulation of miRNAs has been linked to a variety of biological processes, including cell division, proliferation, apoptosis, and inflammation. Numerous research studies have looked into the relationship between genetic variants in miRNA genes and CHD susceptibility. This review highlights the recent research work carried out to identify the relationship of miRNA genes polymorphism with the progression and susceptibility of CHD. Such studies could pave the way for the development of personalized strategies for CHD prevention and treatment based on an individual's genetic profile.

Lack of association between the -2549 insertion/deletion variant of vascular endothelial growth factor and coronary artery disease in the Turkish population

OBJECTIVE

Coronary artery disease is the leading cause of death worldwide. Vascular endothelial growth factor is known to induce endothelial cell migration and proliferation, increase vascular permeability, and modulate thrombogenicity. The aim of this study is to investigate the relationship between the VEGF insertion/deletion (I/D) variant (rs35569394) and coronary artery disease susceptibility in the Turkish population.

METHODS

A total of 206 subjects, including 106 coronary artery disease patients and 100 controls, were included in this study. The VEGF I/D variant was genotyped using the polymerase chain reaction method.

RESULTS

The frequency of the I/I, I/D, and D/D genotypes was 35.84 versus 37%, 33.97 versus 36%, and 30.19 versus 27% in patients and the control group, respectively. VEGF I/D genotype and allele distribution were not statistically significant between coronary artery disease patients and controls (p>0.05). There was no significant difference between VEGF I/D genotype distribution and patient characteristics including age, gender, disease duration, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, history of hypertension, history of diabetes mellitus, and smoking (p>0.05).

CONCLUSION

This study suggests that the VEGF I/D variant is not a predisposing factor to coronary artery disease disease in a Turkish sample.

GWAS breakthroughs: mapping the journey from one locus to 393 significant coronary artery disease associations

Coronary artery disease (CAD) poses a substantial threat to global health, leading to significant morbidity and mortality worldwide. It has a significant genetic component that has been studied through genome-wide association studies (GWAS) over the past 17 years. These studies have made progress with larger sample sizes, diverse ancestral backgrounds, and the discovery of multiple genomic regions related to CAD risk. In this review, we provide a comprehensive overview of CAD GWAS, including information about the genetic makeup of the disease and the importance of ethnic diversity in these studies. We also discuss challenges of identifying causal genes and variants within GWAS loci with a focus on non-coding regions. Additionally, we highlight tissues and cell types relevant to CAD, and discuss clinical implications of GWAS findings including polygenic risk scores, sex-specific differences in CAD genetics, ethnical aspects of personalized interventions, and GWAS guided drug development.

Rare variant contribution to the heritability of coronary artery disease

Whole genome sequences (WGS) enable discovery of rare variants which may contribute to missing heritability of coronary artery disease (CAD). To measure their contribution, we apply the GREML-LDMS-I approach to WGS of 4949 cases and 17,494 controls of European ancestry from the NHLBI TOPMed program. We estimate CAD heritability at 34.3% assuming a prevalence of 8.2%. Ultra-rare (minor allele frequency ≤ 0.1%) variants with low linkage disequilibrium (LD) score contribute ~50% of the heritability. We also investigate CAD heritability enrichment using a diverse set of functional annotations: i) constraint; ii) predicted protein-altering impact; iii) cis-regulatory elements from a cell-specific chromatin atlas of the human coronary; and iv) annotation principal components representing a wide range of functional processes. We observe marked enrichment of CAD heritability for most functional annotations. These results reveal the predominant role of ultra-rare variants in low LD on the heritability of CAD. Moreover, they highlight several functional processes including cell type-specific regulatory mechanisms as key drivers of CAD genetic risk.

Population Heterogeneity and Selection of Coronary Artery Disease Polygenic Scores

BACKGROUND/OBJECTIVES

The identification of coronary artery disease (CAD) high-risk individuals is a major clinical need for timely diagnosis and intervention. Many different polygenic scores (PGSs) for CAD risk are available today to estimate the genetic risk. It is necessary to carefully choose the score to use, in particular for studies on populations, which are not adequately represented in the large datasets of European biobanks, such as the Italian one. This work aimed to analyze which PGS had the best performance within the Italian population.

METHODS

We used two Italian independent cohorts: the EPICOR case-control study (576 individuals) and the Atherosclerosis, Thrombosis, and Vascular Biology (ATVB) Italian study (3359 individuals). We evaluated 266 PGS for cardiovascular disease risk from the PGS Catalog, selecting 51 for CAD.

RESULTS

Distributions between patients and controls were significantly different for 49 scores (p-value < 0.01). Only five PGS have been trained and tested for the European population specifically. PGS003727 demonstrated to be the most accurate when evaluated independently (EPICOR AUC = 0.68; ATVB AUC = 0.80). Taking into account the conventional CAD risk factors further enhanced the performance of the model, particularly in the ATVB study (p-value = 0.0003).

CONCLUSIONS

European CAD PGS could have different risk estimates in peculiar populations, such as the Italian one, as well as in various geographical macro areas. Therefore, further evaluation is recommended for clinical applicability.

Exploring Sex Differences in Pain Manifestation of Coronary Artery Disease through Mendelian Randomization

Pain manifestation following coronary artery disease (CAD) disease differs between men and women. Here, we aimed to provide evidence favoring possible differences in pain manifestation between men and women following CAD using Mendelian randomization (MR). We used summary-level data from sex-stratified genome-wide association studies on CAD and self-reported and clinically diagnosed chest, neck and shoulder, back, and facial pain using data from the UK Biobank cohort (N > 450,000) followed by two-sample MR (sensitivity) analyses. We identified 32 and 19 independent genetic variants associated with CAD for men and women, respectively, as instrumental variables. Genetically influenced CAD was associated with a higher risk of self-reported chest pain in both men (OR: 1.27, CI: 1.2-1.33) and women (OR: 1.44, CI: 1.20-1.73), with similar results for clinically diagnosed chest pain (men OR: 1.22, CI: 1.17-1.26; women OR: 1.31, CI: 1.18-1.46). In addition, in women only, genetically influenced CAD was associated with a higher risk of back pain (OR: 1.35, CI: 1.03-1.66) and neck and shoulder pain (OR: 1.22, CI: 0.91-1.63) (p-values for interaction with men: 0.030 and 0.041, respectively). Sensitivity analysis did not indicate the results were biased by directional pleiotropy. We found evidence, based on genetic predisposition for CAD, for different pain manifestations of CAD in men and women. While CAD was associated with chest pain in both sexes, we only found evidence for a higher risk of back pain and neck and shoulder pain in women, supporting common notions that women may present more often with uncharacteristic anginal symptoms.

Exome sequence analysis identifies rare coding variants associated with a machine learning-based marker for coronary artery disease

Coronary artery disease (CAD) exists on a spectrum of disease represented by a combination of risk factors and pathogenic processes. An in silico score for CAD built using machine learning and clinical data in electronic health records captures disease progression, severity and underdiagnosis on this spectrum and could enhance genetic discovery efforts for CAD. Here we tested associations of rare and ultrarare coding variants with the in silico score for CAD in the UK Biobank, All of Us Research Program and BioMe Biobank. We identified associations in 17 genes; of these, 14 show at least moderate levels of prior genetic, biological and/or clinical support for CAD. We also observed an excess of ultrarare coding variants in 321 aggregated CAD genes, suggesting more ultrarare variant associations await discovery. These results expand our understanding of the genetic etiology of CAD and illustrate how digital markers can enhance genetic association investigations for complex diseases.

MCP-1 rs1024611 Polymorphism, MCP-1 Concentrations, and Premature Coronary Artery Disease: Results of the Genetics of Atherosclerotic Disease (GEA) Mexican Study

Monocyte chemoattractant protein-1 (MCP-1) participates in the initiation and progression of atherosclerosis. In vitro studies have reported that the MCP-1 rs1024611 polymorphism is associated with increased MCP-1 concentrations. The study aimed to define whether MCP-1 concentrations are associated with premature coronary artery disease (pCAD) and to establish whether variations in the rs1024611 polymorphism increase MCP-1 concentrations. MCP-1 rs1024611 polymorphism was determined in 972 pCAD patients and 1070 control individuals by real-time PCR. MCP-1 concentrations were determined by the Bio-Plex system. In the total population, men had higher MCP-1 concentrations when compared to women (p < 0.001). When stratified by rs1024611 genotypes, higher MCP-1 concentrations were observed in AA individuals compared to GG subjects (p = 0.023). When performing the analysis considering sex, the differences remained significant in women (AA vs. GG, p = 0.028 and GA vs. GG, p = 0.008). MCP-1 concentrations were similar in pCAD patients and controls (p = 0.782). However, the independent analysis of the studied groups showed that in patients with the AA genotype, MCP-1 concentrations were significantly higher when compared to patients with the GG genotype (p = 0.009). Considering that the AA genotype increases MCP-1 concentration, we evaluated whether, in AA genotype carriers, MCP-1 concentrations were associated with pCAD. The results showed that for every ten pg/mL increase in MCP-1 concentration, the risk of presenting pCAD increases by 2.7% in AA genotype individuals. Individuals with the MCP-1 rs1024611 AA genotype present an increase in MCP-1 concentration. In those individuals, increased MCP-1 concentrations increase the risk of presented pCAD.

Contribution of genetic variants in the development of familial premature coronary artery disease in a cohort of cardiac patients

Coronary artery disease (CAD), the most prevalent cardiovascular disease, is the leading cause of death worldwide. Heritable factors play a significant role in the pathogenesis of CAD. It has been proposed that approximately one-third of patients with CAD have a positive family history, and individuals with such history are at ~1.5-fold increased risk of CAD in their lifespans. Accordingly, the long-recognized familial clustering of CAD is a strong risk factor for this disease. Our study aimed to identify candidate genetic variants contributing to CAD by studying a cohort of 60 large Iranian families with at least two members in different generations afflicted with premature CAD (PCAD), defined as established disease at ≤45 years in men and ≤55 years in women. Exome sequencing was performed for a subset of the affected individuals, followed by prioritization and Sanger sequencing of candidate variants in all available family members. Subsequently, apparently healthy carriers of potential risk variants underwent coronary computed tomography angiography (CCTA), followed by co-segregation analysis of the combined data. Putative causal variants were identified in seven genes, ABCG8, CD36, CYP27A1, PIK3C2G, RASSF9, RYR2, and ZFYVE21, co-segregating with familial PCAD in seven unrelated families. Among these, PIK3C2G, RASSF9, and ZFYVE21 are novel candidate CAD susceptibility genes. Our findings indicate that rare variants in genes identified in this study are involved in CAD development.

Identification of novel genes associated with atherosclerosis in Bama miniature pig

BACKGROUND

Atherosclerosis is a chronic cardiovascular disease of great concern. However, it is difficult to establish a direct connection between conventional small animal models and clinical practice. The pig's genome, physiology, and anatomy reflect human biology better than other laboratory animals, which is crucial for studying the pathogenesis of atherosclerosis.

METHODS

We used whole-genome sequencing data from nine Bama minipigs to perform a genome-wide linkage analysis, and further used bioinformatic tools to filter and identify underlying candidate genes. Candidate gene function prediction was performed using the online prediction tool STRING 12.0. Immunohistochemistry and immunofluorescence were used to detect the expression of proteins encoded by candidate genes.

RESULTS

We mapped differential single nucleotide polymorphisms (SNPs) to genes and obtained a total of 102 differential genes, then we used GO and KEGG pathway enrichment analysis to identify four candidate genes, including SLA-1, SLA-2, SLA-3, and TAP2. nsSNPs cause changes in the primary and tertiary structures of SLA-I and TAP2 proteins, the primary structures of these two proteins have undergone amino acid changes, and the tertiary structures also show slight changes. In addition, immunohistochemistry and immunofluorescence results showed that the expression changes of TAP2 protein in coronary arteries showed a trend of increasing from the middle layer to the inner layer.

CONCLUSIONS

We have identified SLA-I and TAP2 as potential susceptibility genes of atherosclerosis, highlighting the importance of antigen processing and immune response in atherogenesis.

Bangladeshi Atherosclerosis Biobank and Hub: The BANGABANDHU Study

Background

Genetic factors contribute significantly to the risk of ischaemic heart disease (IHD), which is the leading cause of mortality in Bangladesh. The BANGABANDHU (Bangladeshi Atherosclerosis Biobank AND Hub) study will allow a hypothesis-free genome-wide association study (GWAS) to identify genetic risk factors associated with ischaemic heart disease patients undergoing coronary artery bypass graft (CABG) surgery in Bangladesh.

Methods

 This is a multi-centre population-based case-control study aimed to evaluate 1500 (Fifteen Hundred) adult (≥18 years of age) people divided into 2 study groups: Case/Proband (750 IHD patients undergoing CABG surgery) and Control (750 healthy people). Spouses or family members are preferred as healthy control subjects due to their shared geographic location and similar environmental exposure.

Results

This will be the first largest DNA repository of CABG patients in Bangladesh, and identifying novel gene loci among CABG patients might help to discover novel therapeutic targets for Bangladeshi IHD patients. Further, identifying and comparing novel gene loci among CABG patients with other ancestry might help devise national guidelines for treating coronary artery disease.

Conclusion

Promising current study results will encourage Bangladeshi researchers and pharmaceutical companies to conduct further studies into the genetic basis of Bangladeshi complex coronary artery disease, which might identify novel genes for therapeutic targets for Bangladeshi patients and strengthen the healthcare standards in Bangladesh.

Integration of a polygenic score into guideline-recommended prediction of cardiovascular disease

BACKGROUND AND AIMS

It is not clear how a polygenic risk score (PRS) can be best combined with guideline-recommended tools for cardiovascular disease (CVD) risk prediction, e.g. SCORE2.

METHODS

A PRS for coronary artery disease (CAD) was calculated in participants of UK Biobank (n = 432 981). Within each tenth of the PRS distribution, the odds ratios (ORs)-referred to as PRS-factor-for CVD (i.e. CAD or stroke) were compared between the entire population and subgroups representing the spectrum of clinical risk. Replication was performed in the combined Framingham/Atherosclerosis Risk in Communities (ARIC) populations (n = 10 757). The clinical suitability of a multiplicative model 'SCORE2 × PRS-factor' was tested by risk reclassification.

RESULTS

In subgroups with highly different clinical risks, CVD ORs were stable within each PRS tenth. SCORE2 and PRS showed no significant interactive effects on CVD risk, which qualified them as multiplicative factors: SCORE2 × PRS-factor = total risk. In UK Biobank, the multiplicative model moved 9.55% of the intermediate (n = 145 337) to high-risk group increasing the individuals in this category by 56.6%. Incident CVD occurred in 8.08% of individuals reclassified by the PRS-factor from intermediate to high risk, which was about two-fold of those remained at intermediate risk (4.08%). Likewise, the PRS-factor shifted 8.29% of individuals from moderate to high risk in Framingham/ARIC.

CONCLUSIONS

This study demonstrates that absolute CVD risk, determined by a clinical risk score, and relative genetic risk, determined by a PRS, provide independent information. The two components may form a simple multiplicative model improving precision of guideline-recommended tools in predicting incident CVD.

Pharmacogenomics-based systematic review of coronary artery disease based on personalized medicine procedure

Background

Coronary artery disease (CAD) is the most common reason for mortality and disability-adjusted life years (DALYs) lost globally. This study aimed to suggest a new gene list for the treatment of CAD by a systematic review of bioinformatics analyses of pharmacogenomics impacts of potential genes and variants.

Methods

PubMed search was filtered by the title including Coronary Artery Disease during 2020-2023. To find the genes with pharmacogenetic impact on the CAD, additional filtrations were considered according to the variant annotations. Protein-Protein Interactions (PPIs), Gene-miRNA Interactions (GMIs), Protein-Drug Interactions (PDIs), and variant annotation assessments (VAAs) performed by STRING-MODEL (ver. 12), Cytoscape (ver. 3.10), miRTargetLink.2., NetworkAnalyst (ver 0.3.0), and PharmGKB.

Results

Results revealed 5618 publications, 1290 papers were qualified, and finally, 650 papers were included. 4608 protein-coding genes were extracted, among them, 1432 unique genes were distinguished and 530 evidence-based repeated genes remained. 71 genes showed a pharmacogenetics-related variant annotation in at least (entirely 6331 annotations). Variant annotation assessment (VAA) showed 532 potential variants for the final report, and finally, the concluding PGs list represented 175 variants. Based on the function and MAF, 57 nonsynonymous variants of 29 Pharmacogenomics-related genes were associated with CAD.

Conclusion

Conclusively, evaluating circulating miR33a in individuals' plasma with CAD, and genotyping of rs2230806, rs2230808, rs2487032, rs12003906, rs2472507, rs2515629, and rs4149297 (ABCA1 variants) lead to precisely prescribing of well-known drugs. Also, the findings of this review can be used in both whole-genome sequencing (WGS) and whole-exome sequencing (WES) analysis in the prognosis and diagnosis of CAD.

The association of Sort1 expression with LDL subfraction and inflammation in patients with coronary artery disease

BACKGROUND

Controversial effect of sortilin on lipoprotein metabolism in the development of atherosclerosis reveals the need for more extensive research.

OBJECTIVES

The aim of this study was to investigate the association between Sort1 gene expression and lipids, lipoprotein subfractions, and inflammation in CAD.

METHODS

The study population included 162 subjects with CAD and 49 healthy individuals. The Sort1 gene expression level was determined by qRT-PCR using Human Sortilin TaqMan Gene Expression Assays. Lipoprotein subclasses were analysed by the Lipoprint system. Serum levels of apolipoprotein and CRP were measured by autoanalyzer.

RESULTS

Sort1 gene expression and atherogenic subfraction (SdLDL) levels were significantly higher (p < 0.001) while atheroprotective subfraction (LbLDL) was lower in the subjects with CAD (p < 0.050). Also, increased Sort1 gene expression levels were observed in those with higher CRP values.

CONCLUSIONS

Our findings reveal that the high Sort1 gene expression has a prominent linear relationship with both the atherogenic LDL phenotype and proinflammation, thereby might contribute to the occurrence of CAD.

Interleukin 6 polymorphisms are associated with cardiovascular risk factors in premature coronary artery disease patients and healthy controls of the GEA Mexican study

BACKGROUND AND AIMS

Interleukin-6 (IL-6) is an acute-phase protein that plays an important role in the inflammatory response, vascular inflammation, and atherosclerosis process. The study aimed to establish whether IL-6 gene polymorphisms and IL-6 concentrations are associated with premature coronary artery disease (pCAD) and cardiovascular risk factors.

METHODS

The IL-6 concentrations and the rs2069827, rs1800796, and rs1800795 IL-6 polymorphisms were determined in 1150 pCAD patients and 1083 healthy controls (coronary artery calcium equal to zero determined by tomography).

RESULTS

The IL-6 polymorphisms studied were not associated with pCAD, but they were associated with cardiovascular risk factors in patients and controls. In controls, under the dominant model, the rs1800795 C allele and the rs2069827 T allele were associated with a low risk of central obesity (OR = 0.401, p = 0.017 and OR = 0.577, p = 0.031, respectively), hypoalphalipoproteinemia (OR = 0.581, p = 0.027 and OR = 0.700, p = 0.014, respectively) and hypertriglyceridemia (OR = 0.575, p = 0.030 and OR = 0.728, p = 0.033, respectively). In pCAD, the rs1800795 C allele was associated with an increased risk of hypoalphalipoproteinemia (OR = 1.370, padditive = 0.025) and increased C-reactive protein (CRP) concentrations (OR = 1.491, padditive = 0.007). pCAD patients had significantly higher serum IL-6 concentrations compared to controls (p = 0.002). In the total population, individuals carrying the rs1800795 GC + CC genotypes had higher levels of IL-6 than carriers of the GG genotype (p = 0.025). In control individuals carrying the C allele (CG + CC), an inverse correlation was observed between IL-6 and HDL-cholesterol levels (p = 0.003).

CONCLUSIONS

In summary, the IL-6 polymorphisms were not associated with pCAD, however, they were associated with cardiovascular risk factors in pCAD patients and healthy controls. Individuals carrying the rs1800795 GC + CC genotypes had higher levels of IL-6 than carriers of the GG genotype.

Association of epistatic effects of MTHFR, ACE, APOB, and APOE gene polymorphisms with the risk of myocardial infarction and unstable angina in Egyptian patients

Despite remarkable discoveries in the genetic susceptibility of coronary artery disease (CAD), a large part of heritability awaits identification. Epistasis or gene-gene interaction has a profound influence on CAD and might contribute to its missed genetic variability; however, this impact was largely unexplored. Here, we appraised the associations of gene-gene interactions and haplotypes of five polymorphisms, namely methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, angiotensin converting enzyme (ACE) insertion/deletion (I/D), apolipoprotein B (APOB) R3500Q, and apolipoprotein E (APOE) ε4 with the risk of myocardial infarction (MI) and unstable angina (UA). Gene-environment interactions with traditional risk factors and clinical data were also scrutinized. This study recruited 100 MI, 50 UA patients, and 100 apparently healthy controls. Logistic regression models were employed in association analyses. We remarked that the single locus effect of individual polymorphisms was relatively weak; however, a magnified effect of their combination via gene-gene interaction may predict MI risk after adjustment for multiple comparisons. Only MTHFR C677T, ACE I/D, and APOB R5300Q were associated with the risk of UA, and the ACE I/D-R3500Q interaction posed a decreased UA risk. APOB R3500Q was in strong linkage disequilibrium with MTHFR C677T, ACE I/D, and APE ε4 polymorphisms. The TCDGε3, CADGε4, and TADGε4-C677T-A1298C-ACE I/D-R3500Q-APOE haplotypes were associated with escalating MI risk, while the CDG or CIG-C677T-ACE I/D-R3500Q haplotype was highly protective against UA risk compared to controls. Interestingly, the CADGε4 and CAIGε3 haplotypes were strongly associated with the presence of diabetes and hypertension, respectively in MI patients; both haplotypes stratified patients according to the ECHO results. In UA, the CDG haplotype was negatively associated with the presence of diabetes or dilated heart. Conclusively, our results advocate that a stronger combined effect of polymorphisms in MTHFR, ACE, APOB, and APOE genes via gene-gene and gene-environment interactions might help in risk stratification of MI and UA patients.

The Inclusion of Underrepresented Populations in Cardiovascular Genetics and Epidemiology

Novel genetic risk markers have helped us to advance the field of cardiovascular epidemiology and refine our current understanding and risk stratification paradigms. The discovery and analysis of variants can help us to tailor prognostication and management. However, populations underrepresented in cardiovascular epidemiology and cardiogenetics research may experience inequities in care if prediction tools are not applicable to them clinically. Therefore, the purpose of this article is to outline the barriers that underrepresented populations can face in participating in genetics research, to describe the current efforts to diversify cardiogenetics research, and to outline strategies that researchers in cardiovascular epidemiology can implement to include underrepresented populations. Mistrust, a lack of diverse research teams, the improper use of sensitive biodata, and the constraints of genetic analyses are all barriers for including diverse populations in genetics studies. The current work is beginning to address the paucity of ethnically diverse genetics research and has already begun to shed light on the potential benefits of including underrepresented and diverse populations. Reducing barriers for individuals, utilizing community-driven research processes, adopting novel recruitment strategies, and pushing for organizational support for diverse genetics research are key steps that clinicians and researchers can take to develop equitable risk stratification tools and improve patient care.

Marital status and genetic liability independently predict coronary heart disease incidence

AIMS

Married individuals have a lower coronary heart disease (CHD) risk than non-married, but the mechanisms behind this are not fully understood. We analyzed whether genetic liability to CHD may affect these associations.

METHODS

Marital status, a polygenic score of CHD (PGS-CHD), and other risk factors for CHD were measured from 35,444 participants (53% female) in Finnish population-based surveys conducted between 1992 and 2012. During the register-based follow-up until 2020, there were 2439 fatal and non-fatal incident CHD cases. The data were analyzed using linear and Cox regression models.

RESULTS

Divorced and cohabiting men and women had a higher genetic risk of CHD than married individuals, but the difference was very small (0.023-0.058 standard deviation of PGS-CHD, p-values 0.011-0.429). Both marital status and PGS-CHD were associated with CHD incidence, but the associations were largely independent. Adjusting for behavioral and metabolic risk factors for CHD explained part of these associations (11-20%). No interaction was found between marital status and PGS-CHD for CHD incidence.

CONCLUSIONS

We showed minor differences between the marital status categories in PGS-CHD and demonstrated that marital status and genetic liability predicted CHD incidence largely independently. This emphasizes the need to measure multiple risk factors when predicting CHD risk.

Effects of Ninjurin 2 polymorphisms on susceptibility to coronary heart disease

OBJECTIVE

The aim of this study was to explore the effects of Ninjurin 2 (NINJ2) polymorphisms on susceptibility to coronary heart disease (CHD).

METHODS

We conducted a case-control study with 499 CHD cases and 505 age and gender-matched controls. Five single nucleotide polymorphisms (SNPs) in NINJ2 (rs118050317, rs75750647, rs7307242, rs10849390, and rs11610368) were genotyped by the Agena MassARRAY platform. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression analysis to assess the association of NINJ2 polymorphisms and CHD risk-adjusted for age and gender. What's more, risk genes and molecular functions were screened via protein-protein interaction (PPI) network and functional enrichment analysis.

RESULTS

Rs118050317 in NINJ2 significantly increased CHD risk in people aged more than 60 years and women. Rs118050317 and rs7307242 had strong relationships with hypertension risk in CHD patients. Additionally, rs75750647 exceedingly raised diabetes risk in cases under multiple models, whereas rs10849390 could protect CHD patients from diabetes in allele, homozygote, and additive models. We also observed two blocks in NINJ2. Further interaction network and enrichment analysis showed that NINJ2 played a greater role in the pathogenesis and progression of CHD.

CONCLUSION

Our results suggest that NINJ2 polymorphisms are associated with CHD risk.

Genetic Predisposition of Atherosclerotic Cardiovascular Disease in Ancient Human Remains

Background

Several computed tomographic studies have shown the presence of atherosclerosis in ancient human remains. However, while it is important to understand the development of atherosclerotic cardiovascular disease (ASCVD), genetic data concerning the prevalence of the disease-associated single nucleotide polymorphisms (SNPs) in our ancestors are scarce.

Objective

For a better understanding of the role of genetics in the evolution of ASCVD, we applied an enrichment capture sequencing approach to mummified human remains from different geographic regions and time periods.

Methods

Twenty-two mummified individuals were analyzed for their genetic predisposition of ASCVD. Next-generation sequencing methods were applied to ancient DNA (aDNA) samples, including a novel enrichment approach specifically designed to capture SNPs associated with ASCVD in genome-wide association studies of modern humans.

Findings

Five out of 22 ancient individuals passed all filter steps for calculating a weighted polygenic risk score (PRS) based on 87 SNPs in 56 genes. PRSs were correlated to scores obtained from contemporary people from around the world and cover their complete range. The genetic results of the ancient individuals reflect their phenotypic results, given that the only two mummies showing calcified atherosclerotic arterial plaques on computed tomography scans are the ones exhibiting the highest calculated PRSs.

Conclusions

These data show that alleles associated with ASCVD have been widespread for at least 5,000 years. Despite some limitations due to the nature of aDNA, our approach has the potential to lead to a better understanding of the interaction between environmental and genetic influences on the development of ASCVD.

Mendelian randomization studies on coronary artery disease: a systematic review and meta-analysis

BACKGROUND

Coronary artery disease (CAD) remains one of the leading causes of mortality worldwide. We aimed to summarize what is currently known with regard to causal modifiable risk factors associated with CAD in populations of diverse ancestries through conducting a systematic review and meta-analysis of Mendelian randomization (MR) studies on CAD.

METHODS

The databases Embase, Medline, Cochrane Library and Web of Science were searched on the 19th and 20th of December 2022 for MR studies with CAD as a primary outcome; keywords of the search strategy included "coronary artery disease" and "mendelian randomization". Studies were included if they were published in the English language, included only human participants, employed Mendelian randomization as the primary methodology and studied CAD as the outcome of interest. The exclusion criteria resulted in the removal of studies that did not align with the predefined inclusion criteria, as well as studies which were systematic reviews themselves, and used the same exposure and outcome source as another study. An ancestry-specific meta-analysis was subsequently conducted on studies which investigated either body mass index, lipid traits, blood pressure or type 2 diabetes as an exposure variable. Assessment of publication bias and sensitivity analyses was conducted for risk of bias assessment in the included studies.

RESULTS

A total of 1781 studies were identified through the database searches after de-duplication was performed, with 47 studies included in the quantitative synthesis after eligibility screening. Approximately 80% of all included study participants for MR studies on CAD were of European descent irrespective of the exposure of interest, while no study included individuals of African ancestry. We found no evidence of differences in terms of direction of causation between ancestry groups; however, the strength of the respective relationships between each exposure and CAD were different, with this finding most evident when blood pressure was the exposure of interest.

CONCLUSIONS

Findings from this review suggest that patterns regarding the causational relationship between modifiable risk factors and CAD do not differ in terms of direction when compared across diverse ancestry populations. Differences in the observed strengths of the respective relationships however are indicative of the value of increasing representation in non-European populations, as novel genetic pathways or functional SNPs relating to CAD may be uncovered through a more global analysis.

SYSTEMATIC REVIEW REGISTRATION

The protocol for this systematic review was registered to the International Prospective Register of Systematic Reviews (PROSPERO) and is publicly available online (CRD42021272726).

Polygenic Risk Score Associates With Atherosclerotic Plaque Characteristics at Autopsy

BACKGROUND

Polygenic risk scores (PRSs) for coronary artery disease (CAD) potentially improve cardiovascular risk prediction. However, their relationship with histopathologic features of CAD has never been examined systematically.

METHODS

From 4327 subjects referred to CVPath by the State of Maryland Office Chief Medical Examiner for sudden death between 1994 and 2015, 2455 cases were randomly selected for genotyping. We generated PRS from 291 known CAD risk loci. Detailed histopathologic examination of the coronary arteries was performed in all subjects. The primary study outcome measurements were histopathologic plaque features determining severity of atherosclerosis, including %stenosis, calcification, thin-cap fibroatheromas, and thrombotic CAD.

RESULTS

After exclusion of cases with insufficient DNA sample quality or with missing data, 954 cases (mean age, 48.8±14.7 years; 75.7% men) remained in the final study cohort. Subjects in the highest PRS quintile exhibited more severe atherosclerosis compared with subjects in the lowest quintile, with greater %stenosis (80.3%±27.0% versus 50.4%±38.7%; adjusted P<0.001) and a higher frequency of calcification (69.6% versus 35.8%; adjusted P=0.004) and thin-cap fibroatheroma (26.7% versus 9.5%; adjusted P=0.007). Even after adjustment for traditional CAD risk factors, subjects within the highest PRS quintile had higher odds of severe atherosclerosis (ie, ≥75% stenosis; adjusted odds ratio, 3.77 [95% CI, 2.10-6.78]; P<0.001) and plaque rupture (adjusted odds ratio, 4.05 [95% CI, 2.26-7.24]; P<0.001). Moreover, subjects within the highest quintile had higher odds of CAD-associated cause of death, especially among those aged ≤50 years (adjusted odds ratio, 4.08 [95% CI, 2.01-8.30]; P<0.001). No statistically significant associations were observed with plaque erosion after adjusting for covariates.

CONCLUSIONS

This is the first autopsy study investigating associations between PRS and atherosclerosis severity at the histopathologic level in subjects with sudden death. Our pathological analysis suggests PRS correlates with plaque burden and features of advanced atherosclerosis and may be useful as a method for CAD risk stratification, especially in younger subjects.

Prioritization of risk genes in colorectal cancer by integrative analysis of multi-omics data and gene networks

Genome-wide association studies (GWASs) have identified over 140 colorectal cancer (CRC)-associated loci; however, target genes at the majority of loci and underlying molecular mechanisms are poorly understood. Here, we utilized a Bayesian approach, integrative risk gene selector (iRIGS), to prioritize risk genes at CRC GWAS loci by integrating multi-omics data. As a result, a total of 105 high-confidence risk genes (HRGs) were identified, which exhibited strong gene dependencies for CRC and enrichment in the biological processes implicated in CRC. Among the 105 HRGs, CEBPB, located at the 20q13.13 locus, acted as a transcription factor playing critical roles in cancer. Our subsequent assays indicated the tumor promoter function of CEBPB that facilitated CRC cell proliferation by regulating multiple oncogenic pathways such as MAPK, PI3K-Akt, and Ras signaling. Next, by integrating a fine-mapping analysis and three independent case-control studies in Chinese populations consisting of 8,039 cases and 12,775 controls, we elucidated that rs1810503, a putative functional variant regulating CEBPB, was associated with CRC risk (OR=0.90, 95%CI=0.86-0.93, P=1.07×10-7). The association between rs1810503 and CRC risk was further validated in three additional multi-ancestry populations consisting of 24,254 cases and 58,741 controls. Mechanistically, the rs1810503 A to T allele change weakened the enhancer activity in an allele-specific manner to decrease CEBPB expression via long-range promoter-enhancer interactions, mediated by the transcription factor, REST, and thus decreased CRC risk. In summary, our study provides a genetic resource and a generalizable strategy for CRC etiology investigation, and highlights the biological implications of CEBPB in CRC tumorigenesis, shedding new light on the etiology of CRC.

A Genome-Wide Association Study of Metabolic Syndrome in the Taiwanese Population

The purpose of this study was to investigate genetic factors associated with metabolic syndrome (MetS) by conducting a large-scale genome-wide association study (GWAS) in Taiwan, addressing the limited data on Asian populations compared to Western populations. Using data from the Taiwan Biobank, comprehensive clinical and genetic information from 107,230 Taiwanese individuals was analyzed. Genotyping data from the TWB1.0 and TWB2.0 chips, including over 650,000 single nucleotide polymorphisms (SNPs), were utilized. Genotype imputation using the 1000 Genomes Project was performed, resulting in more than 9 million SNPs. MetS was defined based on a modified version of the Adult Treatment Panel III criteria. Among all participants (mean age: 50 years), 23% met the MetS definition. GWAS analysis identified 549 SNPs significantly associated with MetS, collectively mapping to 10 genomic risk loci. Notable risk loci included rs1004558, rs3812316, rs326, rs4486200, rs2954038, rs10830963, rs662799, rs62033400, rs183130, and rs34342646. Gene-set analysis revealed 22 associated genes: CETP, LPL, APOA5, SIK3, ZPR1, APOC1, BUD13, MLXIPL, TOMM40, GCK, YKT6, RPS6KB1, FTO, VMP1, TUBD1, BCL7B, C19orf80 (ANGPTL8), SIDT2, SENP7, PAFAH1B2, DOCK6, and FOXA2. This study identified genomic risk loci for MetS in a large Taiwanese population through a comprehensive GWAS approach. These associations provide novel insights into the genetic basis of MetS and hold promise for the potential discovery of clinical biomarkers.

Integrated omics analysis of coronary artery calcifications and myocardial infarction: the Framingham Heart Study

Gene function can be described using various measures. We integrated association studies of three types of omics data to provide insights into the pathophysiology of subclinical coronary disease and myocardial infarction (MI). Using multivariable regression models, we associated: (1) single nucleotide polymorphism, (2) DNA methylation, and (3) gene expression with coronary artery calcification (CAC) scores and MI. Among 3106 participants of the Framingham Heart Study, 65 (2.1%) had prevalent MI and 60 (1.9%) had incident MI, median CAC value was 67.8 [IQR 10.8, 274.9], and 1403 (45.2%) had CAC scores > 0 (prevalent CAC). Prevalent CAC was associated with AHRR (linked to smoking) and EXOC3 (affecting platelet function and promoting hemostasis). CAC score was associated with VWA1 (extracellular matrix protein associated with cartilage structure in endomysium). For prevalent MI we identified FYTTD1 (down-regulated in familial hypercholesterolemia) and PINK1 (linked to cardiac tissue homeostasis and ischemia-reperfusion injury). Incident MI was associated with IRX3 (enhancing browning of white adipose tissue) and STXBP3 (controlling trafficking of glucose transporter type 4 to plasma). Using an integrative trans-omics approach, we identified both putatively novel and known candidate genes associated with CAC and MI. Replication of findings is warranted.

Genome-wide association studies on coronary artery disease: A systematic review and implications for populations of different ancestries

BACKGROUND

Cardiovascular diseases are some of the leading causes of death worldwide, with coronary artery disease leading as one of the primary causes of mortality in both the developing and developed worlds. Despite its prevalence, there is a disproportionately small number of studies conducted in populations of non-European ancestry, with the limited sample sizes of such studies further restricting the power and generalizability of respective findings. This research aimed at understanding the differences in the genetic architecture of coronary artery disease (CAD) in populations of diverse ancestries in order to contribute towards the understanding of the pathophysiology of coronary artery disease.

METHODS

We performed a systematic review on the 6th of October, 2022 summarizing genome-wide association studies on coronary artery disease, while employing the GWAS Catalog as an independent database to support the search. We developed a framework to assess the methodological quality of each study. We extracted and grouped associated single nucleotide polymorphisms and genes according to ancestry groups of participants.

RESULTS

We identified 3100 studies, of which, 36 relevant studies were included in this research. Three of the studies that were included were not listed in the GWAS Catalog, highlighting the value of conducting an independent search alongside established databases in order to ensure the full research landscape has been captured. 743,919 CAD case participants from 25 different countries were analysed, with 61% of the studies identified in this research conducted in populations of European ancestry. No studies investigated populations of Africans living in continental Africa or admixed American ancestry groups besides African-Americans, while limited sample sizes were included of population groups besides Europeans and East Asians. This observed disproportionate population representation highlights the gaps in the literature, which limits our ability to understand coronary artery disease as a global disease. 71 genetic loci were identified to be associated with coronary artery disease in more than one article, with ancestry-specific genetic loci identified in each respective population group which were not detected in studies of other ancestries.

CONCLUSIONS

Although the replication and validation of these variants are still warranted, these finding are indicative of the value of including diverse ancestry populations in GWAS reference panels, as a more comprehensive understanding of the genetic architecture and pathophysiology of CAD can be achieved.

Sex differences in the genetic and molecular mechanisms of coronary artery disease

Sex differences in coronary artery disease (CAD) presentation, risk factors and prognosis have been widely studied. Similarly, studies on atherosclerosis have shown prominent sex differences in plaque biology. Our understanding of the underlying genetic and molecular mechanisms that drive these differences remains fragmented and largely understudied. Through reviewing genetic and epigenetic studies, we identified more than 40 sex-differential candidate genes (13 within known CAD loci) that may explain, at least in part, sex differences in vascular remodeling, lipid metabolism and endothelial dysfunction. Studies with transcriptomic and single-cell RNA sequencing data from atherosclerotic plaques highlight potential sex differences in smooth muscle cell and endothelial cell biology. Especially, phenotypic switching of smooth muscle cells seems to play a crucial role in female atherosclerosis. This matches the known sex differences in atherosclerotic phenotypes, with men being more prone to lipid-rich plaques, while women are more likely to develop fibrous plaques with endothelial dysfunction. To unravel the complex mechanisms that drive sex differences in CAD, increased statistical power and adjustments to study designs and analysis strategies are required. This entails increasing inclusion rates of women, performing well-defined sex-stratified analyses and the integration of multi-omics data.

Exploring the role of Sirtuin 3 gene polymorphisms and oxidative stress markers in the susceptibility to coronary artery disease

OBJECTIVE

Coronary artery disease (CAD) is a complex disorder influenced by genetic and environmental factors. This case-control study investigated the association between Sirtuin SIRT3 gene polymorphisms, serum malondialdehyde (MDA) levels, and CAD susceptibility.

METHODS

Blood samples were collected from 70 CAD cases and 30 controls at the Cardiac Center, Azadi Teaching Hospital, Duhok, Iraq. Genomic DNA was extracted, and PCR-based allele genotyping determined SIRT3 rs11246029 T/C polymorphisms. Serum MDA levels were measured using ELISA. Statistical analysis included t-tests, Mann-Whitney tests, and Spearman correlations. Odds ratios (OR) with 95% confidence intervals (CI) assessed genotypes/alleles and CAD associations. The accuracy of serum MDA in predicting the severity of CAD was evaluated using receiver operating characteristic (ROC) curve analysis.

RESULTS

There were no significant variations in serum MDA levels between controls and CAD patients in the study. The diagnostic accuracy of serum MDA for CAD severity prediction was modest (Area Under Curve (AUC) = 0.56). Correlations revealed associations between MDA and total bilirubin (negative) and Troponin (positive). CRP correlated positively with LDH, glucose, cholesterol, LDL, CKmB, and Troponin. CKmB and Troponin are positively associated with clinical characteristics. Genotype analysis identified a significantly higher CAD risk with the CC genotype compared to controls.

CONCLUSION

These findings shed light on the potential role of SIRT3 gene polymorphisms and serum MDA levels in CAD susceptibility. Further research is needed to understand underlying mechanisms and therapeutic implications based on these markers.

TRIAL REGISTRATION

15092021-9-12. Registered 15 September 2021.

Transcription factor 21 gene and prognosis in a coronary population

INTRODUCTION AND OBJECTIVES

Transcription factor 21 (TCF21) is a member of the basic helix-loop-helix (bHLH) transcription factor family, and is critical for embryogenesis of the heart. It regulates differentiation of epicardium-derived cells into smooth muscle cell (SMC) and fibroblast lineages. The biological role of TCF21 in the progression of atherosclerosis is the subject of debate. The aim of this study was to investigate the impact of the TCF21 rs12190287 gene variant on the prognosis of coronary artery disease (CAD) in a Portuguese population from Madeira island.

METHODS

We analyzed major adverse cardiovascular events (MACE) in 1713 CAD patients, mean age 53.3±7.8, 78.7% male, for 5.0±4.3 years. Genotype and allele distribution between groups with and without MACE was determined. The dominant genetic model (heterozygous GC plus homozygous CC) was used and compared with the wild GG to assess survival probability. Cox regression with risk factors and genetic models assessed variables associated with MACE. Kaplan-Meier analysis was used to estimate survival.

RESULTS

The wild homozygous GG, heterozygous GC and risk CC genotypes were found in 9.5%, 43.2% and 47.3% of the population, respectively. The dominant genetic model remained in the equation as an independent risk factor for MACE (HR 1.41; p=0.033), together with multivessel disease, chronic kidney disease, low physical activity and type 2 diabetes. The C allele in the dominant genetic model showed worse survival (22.5% vs. 44.3%) at 15 years of follow-up.

CONCLUSION

The TCF21 rs12190287 variant is a risk factor for CAD events. This gene may influence fundamental SMC processes in response to vascular stress, accelerating atherosclerosis progression, and may represent a target for future therapies.

Current Data and New Insights into the Genetic Factors of Atherogenic Dyslipidemia Associated with Metabolic Syndrome

Atherogenic dyslipidemia plays a critical role in the development of metabolic syndrome (MetS), being one of its major components, along with central obesity, insulin resistance, and hypertension. In recent years, the development of molecular genetics techniques and extended analysis at the genome or exome level has led to important progress in the identification of genetic factors (heritability) involved in lipid metabolism disorders associated with MetS. In this review, we have proposed to present the current knowledge related to the genetic etiology of atherogenic dyslipidemia, but also possible challenges for future studies. Data from the literature provided by candidate gene-based association studies or extended studies, such as genome-wide association studies (GWAS) and whole exome sequencing (WES,) have revealed that atherogenic dyslipidemia presents a marked genetic heterogeneity (monogenic or complex, multifactorial). Despite sustained efforts, many of the genetic factors still remain unidentified (missing heritability). In the future, the identification of new genes and the molecular mechanisms by which they intervene in lipid disorders will allow the development of innovative therapies that act on specific targets. In addition, the use of polygenic risk scores (PRS) or specific biomarkers to identify individuals at increased risk of atherogenic dyslipidemia and/or other components of MetS will allow effective preventive measures and personalized therapy.

Polygenic Risk Score Associates with Atherosclerotic Plaque Characteristics at Autopsy

Background

Polygenic risk scores (PRS) for coronary artery disease (CAD) potentially improve cardiovascular risk prediction. However, their relationship with histopathologic features of CAD has never been examined systematically.

Methods

From 4,327 subjects referred to CVPath by the State of Maryland Office Chief Medical Examiner (OCME) for sudden death between 1994 and 2015, 2,455 cases were randomly selected for genotyping. We generated PRS from 291 known CAD risk loci. Detailed histopathologic examination of the coronary arteries was performed in all subjects. The primary study outcome measurements were histopathologic plaque features determining severity of atherosclerosis, including %stenosis, calcification, thin-cap fibroatheromas (TCFA), and thrombotic CAD.

Results

After exclusion of cases with insufficient DNA sample quality or with missing data, 954 cases (mean age 48.8±14.7; 75.7% men) remained in the final study cohort. Subjects in the highest PRS quintile exhibited more severe atherosclerosis compared to subjects in the lowest quintile, with greater %stenosis (80.3%±27.0% vs. 50.4%±38.7%; adjusted p<0.001) and a higher frequency of calcification (69.6% vs. 35.8%; adjusted p=0.004) and TCFAs (26.7% vs. 9.5%; adjusted p=0.007). Even after adjustment for traditional CAD risk factors subjects within the highest PRS quintile had higher odds of severe atherosclerosis (i.e., ≥75% stenosis; adjusted OR 3.77; 95%CI 2.10-6.78; p<0.001) and plaque rupture (adjusted OR 4.05; 95%CI 2.26-7.24; p<0.001). Moreover, subjects within the highest quintile had higher odds of CAD-associated cause of death, especially among those aged 50 years and younger (adjusted OR 4.08; 95%CI 2.01-8.30; p<0.001). No associations were observed with plaque erosion.

Conclusions

This is the first autopsy study investigating associations between PRS and atherosclerosis severity at the histopathologic level in subjects with sudden death. Our pathological analysis suggests PRS correlates with plaque burden and features of advanced atherosclerosis and may be useful as a method for CAD risk stratification, especially in younger subjects.

Highlights

In this autopsy study including 954 subjects within the CVPath Sudden Death Registry, high PRS correlated with plaque burden and atherosclerosis severity.The PRS showed differential associations with plaque rupture and plaque erosion, suggesting different etiologies to these two causes of thrombotic CAD.PRS may be useful for risk stratification, particularly in the young. Further examination of individual risk loci and their association with plaque morphology may help understand molecular mechanisms of atherosclerosis, potentially revealing new therapy targets of CAD.

Graphic Abstract

A polygenic risk score, generated from 291 known CAD risk loci, was assessed in 954 subjects within the CVPath Sudden Death Registry. Histopathologic examination of the coronary arteries was performed in all subjects. Subjects in the highest PRS quintile exhibited more severe atherosclerosis as compared to subjects in the lowest quintile, with a greater plaque burden, more calcification, and a higher frequency of plaque rupture.

Genomic Innovation in Early Life Cardiovascular Disease Prevention and Treatment

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality globally. Although CVD events do not typically manifest until older adulthood, CVD develops gradually across the life-course, beginning with the elevation of risk factors observed as early as childhood or adolescence and the emergence of subclinical disease that can occur in young adulthood or midlife. Genomic background, which is determined at zygote formation, is among the earliest risk factors for CVD. With major advances in molecular technology, including the emergence of gene-editing techniques, along with deep whole-genome sequencing and high-throughput array-based genotyping, scientists now have the opportunity to not only discover genomic mechanisms underlying CVD but use this knowledge for the life-course prevention and treatment of these conditions. The current review focuses on innovations in the field of genomics and their applications to monogenic and polygenic CVD prevention and treatment. With respect to monogenic CVD, we discuss how the emergence of whole-genome sequencing technology has accelerated the discovery of disease-causing variants, allowing comprehensive screening and early, aggressive CVD mitigation strategies in patients and their families. We further describe advances in gene editing technology, which might soon make possible cures for CVD conditions once thought untreatable. In relation to polygenic CVD, we focus on recent innovations that leverage findings of genome-wide association studies to identify druggable gene targets and develop predictive genomic models of disease, which are already facilitating breakthroughs in the life-course treatment and prevention of CVD. Gaps in current research and future directions of genomics studies are also discussed. In aggregate, we hope to underline the value of leveraging genomics and broader multiomics information for characterizing CVD conditions, work which promises to expand precision approaches for the life-course prevention and treatment of CVD.

Exploring the genetic basis of coronary artery disease using functional genomics

Genome-wide Association Studies (GWAS) have identified more than 300 loci associated with coronary artery disease (CAD), defining the genetic risk map of the disease. However, the translation of the association signals into biological-pathophysiological mechanisms constitute a major challenge. Through a group of examples of studies focused on CAD, we discuss the rationale, basic principles and outcomes of the main methodologies implemented to prioritize and characterize causal variants and their target genes. Additionally, we highlight the strategies as well as the current methods that integrate association and functional genomics data to dissect the cellular specificity underlying the complexity of disease mechanisms. Despite the limitations of existing approaches, the increasing knowledge generated through functional studies helps interpret GWAS maps and opens novel avenues for the clinical usability of association data.

Coronary Artery Disease Risk Gene PRDM16 is Preferentially Expressed in Vascular Smooth Muscle Cells and a Potential Novel Regulator of Smooth Muscle Homeostasis

Objective

Vascular smooth muscle cells (VSMCs) are the primary contractile component of blood vessels and can undergo phenotypic switching from a contractile to a synthetic phenotype in vascular diseases such as coronary artery disease (CAD). This process leads to decreased expression of SMC lineage genes and increased proliferative, migratory and secretory abilities that drive disease progression. Super-enhancers (SE) and occupied transcription factors are believed to drive expression of genes that maintain cell identify and homeostasis. The goal of this study is to identify novel regulator of VSMC homeostasis by screening for SE-regulated transcription factors in arterial tissues.

Approach and Results

We characterized human artery SEs by analyzing the enhancer histone mark H3K27ac ChIP-seq data of multiple arterial tissues. We unexpectedly discovered the transcription factor PRDM16, a GWAS identified CAD risk gene with previously well-documented roles in brown adipocytes but with an unknown function in vascular disease progression, is enriched with artery-specific SEs. Further analysis of public bulk RNA-seq and scRNA-seq datasets, as well as qRT-PCR and Western blotting analysis, demonstrated that PRDM16 is preferentially expressed in arterial tissues and in contractile VSMCs but not in visceral SMCs, and down-regulated in phenotypically modulated VSMCs. To explore the function of Prdm16 in vivo, we generated Prdm16 SMC-specific knockout mice and performed histological and bulk RNA-Seq analysis of aortic tissues. SMC-deficiency of Prdm16 does not affect the aortic morphology but significantly alters expression of many CAD risk genes and genes involved in VSMC phenotypic modulation. Specifically, Prdm16 negatively regulates the expression of Tgfb2 that encodes for an upstream ligand of TGF-β signaling pathway, potentially through binding to the promoter region of Tgfb2 . These transcriptomic changes likely disrupt VSMC homeostasis and predispose VSMCs to a disease state.

Conclusions

Our results suggest that the CAD risk gene PRDM16 is preferentially expressed in VSMCs and is a novel regulator of VSMC homeostasis. Future studies are warranted to investigate its role in VSMCs under pathological conditions such as atherosclerosis.

Genetic and modifiable risk factors combine multiplicatively in common disease

BACKGROUND

The joint contribution of genetic and environmental exposures to noncommunicable diseases is not well characterized.

OBJECTIVES

We modeled the cumulative effects of common risk alleles and their prevalence variations with classical risk factors.

METHODS

We analyzed mathematically and statistically numbers and effect sizes of established risk alleles for coronary artery disease (CAD) and other conditions.

RESULTS

In UK Biobank, risk alleles counts in the lowest (175.4) and highest decile (205.7) of the distribution differed by only 16.9%, which nevertheless increased CAD prevalence 3.4-fold (p < 0.01). Irrespective of the affected gene, a single risk allele multiplied the effects of all others carried by a person, resulting in a 2.9-fold stronger effect size in the top versus the bottom decile (p < 0.01) and an exponential increase in risk (R > 0.94). Classical risk factors shifted effect sizes to the steep upslope of the logarithmic function linking risk allele numbers with CAD prevalence. Similar phenomena were observed in the Estonian Biobank and for risk alleles affecting diabetes mellitus, breast and prostate cancer.

CONCLUSIONS

Alleles predisposing to common diseases can be carried safely in large numbers, but few additional ones lead to sharp risk increments. Here, we describe exponential functions by which risk alleles combine interchangeably but multiplicatively with each other and with modifiable risk factors to affect prevalence. Our data suggest that the biological systems underlying these diseases are modulated by hundreds of genes but become only fragile when a narrow window of total risk, irrespective of its genetic or environmental origins, has been passed.

Advances and Applications of Polygenic Scores for Coronary Artery Disease

Polygenic scores quantify inherited risk by integrating information from many common sites of DNA variation into a single number. Rapid increases in the scale of genetic association studies and new statistical algorithms have enabled development of polygenic scores that meaningfully measure-as early as birth-risk of coronary artery disease. These newer-generation polygenic scores identify up to 8% of the population with triple the normal risk based on genetic variation alone, and these individuals cannot be identified on the basis of family history or clinical risk factors alone. For those identified with increased genetic risk, evidence supports risk reduction with at least two interventions, adherence to a healthy lifestyle and cholesterol-lowering therapies, that can substantially reduce risk. Alongside considerable enthusiasm for the potential of polygenic risk estimation to enable a new era of preventive clinical medicine is recognition of a need for ongoing research into how best to ensure equitable performance across diverse ancestries, how and in whom to assess the scores in clinical practice, as well as randomized trials to confirm clinical utility.

Epigenetics in the primary and secondary prevention of cardiovascular disease: influence of exercise and nutrition

Increasing evidence links changes in epigenetic systems, such as DNA methylation, histone modification, and non-coding RNA expression, to the occurrence of cardiovascular disease (CVD). These epigenetic modifications can change genetic function under influence of exogenous stimuli and can be transferred to next generations, providing a potential mechanism for inheritance of behavioural intervention effects. The benefits of exercise and nutritional interventions in the primary and secondary prevention of CVD are well established, but the mechanisms are not completely understood. In this review, we describe the acute and chronic epigenetic effects of physical activity and dietary changes. We propose exercise and nutrition as potential triggers of epigenetic signals, promoting the reshaping of transcriptional programmes with effects on CVD phenotypes. Finally, we highlight recent developments in epigenetic therapeutics with implications for primary and secondary CVD prevention.

A Unified Model of Age-Related Cardiovascular Disease

Despite progress in biomedical technologies, cardiovascular disease remains the main cause of mortality. This is at least in part because current clinical interventions do not adequately take into account aging as a driver and are hence aimed at suboptimal targets. To achieve progress, consideration needs to be given to the role of cell aging in disease pathogenesis. We propose a model unifying the fundamental processes underlying most age-associated cardiovascular pathologies. According to this model, cell aging, leading to cell senescence, is responsible for tissue changes leading to age-related cardiovascular disease. This process, occurring due to telomerase inactivation and telomere attrition, affects all components of the cardiovascular system, including cardiomyocytes, vascular endothelial cells, smooth muscle cells, cardiac fibroblasts, and immune cells. The unified model offers insights into the relationship between upstream risk factors and downstream clinical outcomes and explains why interventions aimed at either of these components have limited success. Potential therapeutic approaches are considered based on this model. Because telomerase activity can prevent and reverse cell senescence, telomerase gene therapy is discussed as a promising intervention. Telomerase gene therapy and similar systems interventions based on the unified model are expected to be transformational in cardiovascular medicine.

Polymorphic Variants of AGT, ABCA1, and CYBA Genes Influence the Survival of Patients with Coronary Artery Disease: A Prospective Cohort Study

Genetic factors can influence the risk of coronary artery disease (CAD) and the survival of patients. Our previous research led to the identification of genetic variants predisposing to CAD in the Polish population. Since many of them affect the clinical phenotype of the disease, the aim of this study was searching for genetic factors potentially influencing survival in patients with CAD. The study included 276 patients hospitalized due to coronary artery disease. The database of medical history and genotypic results of 29 polymorphisms were used. The endpoint was defined as death from cardiovascular causes. Survival was defined as the period from angiographic confirmation of CAD to death from cardiovascular causes. Three of all the analyzed genes were associated with survival. In the case of the AGT (rs699) and ABCA1 (rs2230806) genes polymorphisms, the risk of death was higher in GG homozygotes compared to the A allele carriers in the 10-year period. In the case of the CYBA (rs72811418) gene polymorphism, the effect on mortality was shown in both 5- and 10-year periods. The TA heterozygotes were predisposed to a higher risk of death than the TT homozygotes. Concluding, the AGT, ABCA1, and CYBA genes polymorphisms influence the risk of death in patients with CAD.

An updated analysis on the association of GSTM1 polymorphism and smoking exposure with the increased risk of coronary heart disease

Objective

To undertake a meta-analysis to investigate if there is an association between the glutathione S-transferase mu 1 (GSTM1) gene polymorphism, coronary artery disease (CAD) susceptibility and smoking.

Methods

Electronic databases, including PubMed®, Web of Science and Embase®, were searched for relevant case–control studies. Data were extracted and the odds ratio (OR) was calculated and appropriate statistical methods were used for the meta-analysis.

Results

The analysis included eight studies with a total of 1880 cases with CAD and 1758 control subjects. The results of this meta-analysis demonstrated that there is no association between the GSTM1 null and CAD (OR 1.24, 95% confidence interval [CI] 1.00, 1.55). An increased risk of CAD was observed in the smoking population with the GSTM1 null genotype (OR 1.48, 95% CI 1.02, 2.15). Subgroup analyses of geographical region, genotyping method and publication language category demonstrated potential relationships among gene polymorphism, smoking and CAD.

Conclusions

Based on the current literature, the GSTM1 null genotype was associated to CAD in the smoking population. The interaction between smoking and GSTM1 polymorphism may contribute to the susceptibility of CAD.