Genes, environment, and cardiovascular disease

Current RNA strategies in treating cardiovascular diseases

Cardiovascular disease (CVD) continues to impose a significant global health burden, necessitating the exploration of innovative treatment strategies. Ribonucleic acid (RNA)-based therapeutics have emerged as a promising avenue to address the complex molecular mechanisms underlying CVD pathogenesis. We present a comprehensive review of the current state of RNA therapeutics in the context of CVD, focusing on the diverse modalities that bring about transient or permanent modifications by targeting the different stages of the molecular biology central dogma. Considering the immense potential of RNA therapeutics, we have identified common gene targets that could serve as potential interventions for prevalent Mendelian CVD caused by single gene mutations, as well as acquired CVDs developed over time due to various factors. These gene targets offer opportunities to develop RNA-based treatments tailored to specific genetic and molecular pathways, presenting a novel and precise approach to address the complex pathogenesis of both types of cardiovascular conditions. Additionally, we discuss the challenges and opportunities associated with delivery strategies to achieve targeted delivery of RNA therapeutics to the cardiovascular system. This review highlights the immense potential of RNA-based interventions as a novel and precise approach to combat CVD, paving the way for future advancements in cardiovascular therapeutics.

Endophenotype trait domains for advancing gene discovery in autism spectrum disorder

Autism spectrum disorder (ASD) is associated with a diverse range of etiological processes, including both genetic and non-genetic causes. For a plurality of individuals with ASD, it is likely that the primary causes involve multiple common inherited variants that individually account for only small levels of variation in phenotypic outcomes. This genetic landscape creates a major challenge for detecting small but important pathogenic effects associated with ASD. To address similar challenges, separate fields of medicine have identified endophenotypes, or discrete, quantitative traits that reflect genetic likelihood for a particular clinical condition and leveraged the study of these traits to map polygenic mechanisms and advance more personalized therapeutic strategies for complex diseases. Endophenotypes represent a distinct class of biomarkers useful for understanding genetic contributions to psychiatric and developmental disorders because they are embedded within the causal chain between genotype and clinical phenotype, and they are more proximal to the action of the gene(s) than behavioral traits. Despite their demonstrated power for guiding new understanding of complex genetic structures of clinical conditions, few endophenotypes associated with ASD have been identified and integrated into family genetic studies. In this review, we argue that advancing knowledge of the complex pathogenic processes that contribute to ASD can be accelerated by refocusing attention toward identifying endophenotypic traits reflective of inherited mechanisms. This pivot requires renewed emphasis on study designs with measurement of familial co-variation including infant sibling studies, family trio and quad designs, and analysis of monozygotic and dizygotic twin concordance for select trait dimensions. We also emphasize that clarification of endophenotypic traits necessarily will involve integration of transdiagnostic approaches as candidate traits likely reflect liability for multiple clinical conditions and often are agnostic to diagnostic boundaries. Multiple candidate endophenotypes associated with ASD likelihood are described, and we propose a new focus on the analysis of "endophenotype trait domains" (ETDs), or traits measured across multiple levels (e.g., molecular, cellular, neural system, neuropsychological) along the causal pathway from genes to behavior. To inform our central argument for research efforts toward ETD discovery, we first provide a brief review of the concept of endophenotypes and their application to psychiatry. Next, we highlight key criteria for determining the value of candidate endophenotypes, including unique considerations for the study of ASD. Descriptions of different study designs for assessing endophenotypes in ASD research then are offered, including analysis of how select patterns of results may help prioritize candidate traits in future research. We also present multiple candidate ETDs that collectively cover a breadth of clinical phenomena associated with ASD, including social, language/communication, cognitive control, and sensorimotor processes. These ETDs are described because they represent promising targets for gene discovery related to clinical autistic traits, and they serve as models for analysis of separate candidate domains that may inform understanding of inherited etiological processes associated with ASD as well as overlapping neurodevelopmental disorders.

Alterations in gut microbiota and host transcriptome of patients with coronary artery disease

BACKGROUND

Coronary artery disease (CAD) is a widespread heart condition caused by atherosclerosis and influences millions of people worldwide. Early detection of CAD is challenging due to the lack of specific biomarkers. The gut microbiota and host-microbiota interactions have been well documented to affect human health. However, investigation that reveals the role of gut microbes in CAD is still limited. This study aims to uncover the synergistic effects of host genes and gut microbes associated with CAD through integrative genomic analyses.

RESULTS

Herein, we collected 52 fecal and 50 blood samples from CAD patients and matched controls, and performed amplicon and transcriptomic sequencing on these samples, respectively. By comparing CAD patients with health controls, we found that dysregulated gut microbes were significantly associated with CAD. By leveraging the Random Forest method, we found that combining 20 bacteria and 30 gene biomarkers could distinguish CAD patients from health controls with a high performance (AUC = 0.92). We observed that there existed prominent associations of gut microbes with several clinical indices relevant to heart functions. Integration analysis revealed that CAD-relevant gut microbe genus Fusicatenibacter was associated with expression of CAD-risk genes, such as GBP2, MLKL, and CPR65, which is in line with previous evidence (Tang et al., Nat Rev Cardiol 16:137-154, 2019; Kummen et al., J Am Coll Cardiol 71:1184-1186, 2018). In addition, the upregulation of immune-related pathways in CAD patients were identified to be primarily associated with higher abundance of genus Blautia, Eubacterium, Fusicatenibacter, and Monoglobus.

CONCLUSIONS

Our results highlight that dysregulated gut microbes contribute risk to CAD by interacting with host genes. These identified microbes and interacted risk genes may have high potentials as biomarkers for CAD.

The contribution of the exposome to the burden of cardiovascular disease

Large epidemiological and health impact assessment studies at the global scale, such as the Global Burden of Disease project, indicate that chronic non-communicable diseases, such as atherosclerosis and diabetes mellitus, caused almost two-thirds of the annual global deaths in 2020. By 2030, 77% of all deaths are expected to be caused by non-communicable diseases. Although this increase is mainly due to the ageing of the general population in Western societies, other reasons include the increasing effects of soil, water, air and noise pollution on health, together with the effects of other environmental risk factors such as climate change, unhealthy city designs (including lack of green spaces), unhealthy lifestyle habits and psychosocial stress. The exposome concept was established in 2005 as a new strategy to study the effect of the environment on health. The exposome describes the harmful biochemical and metabolic changes that occur in our body owing to the totality of different environmental exposures throughout the life course, which ultimately lead to adverse health effects and premature deaths. In this Review, we describe the exposome concept with a focus on environmental physical and chemical exposures and their effects on the burden of cardiovascular disease. We discuss selected exposome studies and highlight the relevance of the exposome concept for future health research as well as preventive medicine. We also discuss the challenges and limitations of exposome studies.

A Systematic Review and Meta-Analysis of Applying Deep Learning in the Prediction of the Risk of Cardiovascular Diseases From Retinal Images

Purpose

The purpose of this study was to perform a systematic review and meta-analysis to synthesize evidence from studies using deep learning (DL) to predict cardiovascular disease (CVD) risk from retinal images.

Methods

A systematic literature search was performed in MEDLINE, Scopus, and Web of Science up to June 2022. We extracted data pertaining to predicted outcomes, model development, and validation and model performance metrics. Included studies were graded using the Quality Assessment of Diagnostic Accuracies Studies 2 tool. Model performance was pooled across eligible studies using a random-effects meta-analysis model.

Results

A total of 26 studies were included in the analysis. There were 42 CVD risk-related outcomes predicted from retinal images were identified, including 33 CVD risk factors, 4 cardiac imaging biomarkers, 2 CVD risk scores, the presence of CVD, and incident CVD. Three studies that aimed to predict the development of future CVD events reported an area under the receiver operating curve (AUROC) between 0.68 and 0.81. Models that used retinal images as input data had a pooled mean absolute error of 3.19 years (95% confidence interval [CI] = 2.95-3.43) for age prediction; a pooled AUROC of 0.96 (95% CI = 0.95-0.97) for gender classification; a pooled AUROC of 0.80 (95% CI = 0.73-0.86) for diabetes detection; and a pooled AUROC of 0.86 (95% CI = 0.81-0.92) for the detection of chronic kidney disease. We observed a high level of heterogeneity and variation in study designs.

Conclusions

Although DL models appear to have reasonably good performance when it comes to predicting CVD risk, further work is necessary to evaluate the real-world applicability and predictive accuracy.

Translational Relevance

DL-based CVD risk assessment from retinal images holds great promise to be translated to clinical practice as a novel approach for CVD risk assessment, given its simple, quick, and noninvasive nature.

Variation in placental microRNA expression associates with maternal family history of cardiovascular disease

In the United States, cardiovascular disease is the leading cause of death and the rate of maternal mortality remains among the highest of any industrialized nation. Maternal cardiometabolic health throughout gestation and postpartum is representative of placental health and physiology. Both proper placental functionality and placental microRNA expression are essential to successful pregnancy outcomes, and both are highly sensitive to genetic and environmental sources of variation. Placental pathologies, such as preeclampsia, are associated with maternal cardiovascular health but may also contribute to the developmental programming of chronic disease in offspring. However, the role of more subtle alterations to placental function and microRNA expression in this developmental programming remains poorly understood. We performed small RNA sequencing to investigate microRNA in placentae from the Rhode Island Child Health Study (n = 230). MicroRNA counts were modeled on maternal family history of cardiovascular disease using negative binomial generalized linear models. MicroRNAs were considered to be differentially expressed at a false discovery rate (FDR) less than 0.10. Parallel mRNA sequencing data and bioinformatic target prediction software were then used to identify potential mRNA targets of differentially expressed microRNAs. Nine differentially expressed microRNAs were identified (FDR < 0.1). Bioinformatic target prediction revealed 66 potential mRNA targets of these microRNAs, many of which are implicated in TGFβ signaling pathway but also in pathways involving cellular metabolism and immunomodulation. A robust association exists between familial cardiovascular disease and placental microRNA expression which may be implicated in both placental insufficiencies and the developmental programming of chronic disease.

Educational attainment as a modifier for the effect of polygenic scores for cardiovascular risk factors: cross-sectional and prospective analysis of UK Biobank

BACKGROUND

Understanding the interplay between educational attainment and genetic predictors of cardiovascular risk may improve our understanding of the aetiology of educational inequalities in cardiovascular disease.

METHODS

In up to 320 120 UK Biobank participants of White British ancestry (mean age = 57 years, female 54%), we created polygenic scores for nine cardiovascular risk factors or diseases: alcohol consumption, body mass index, low-density lipoprotein cholesterol, lifetime smoking behaviour, systolic blood pressure, atrial fibrillation, coronary heart disease, type 2 diabetes and stroke. We estimated whether educational attainment modified genetic susceptibility to these risk factors and diseases.

RESULTS

On the additive scale, higher educational attainment reduced genetic susceptibility to higher body mass index, smoking, atrial fibrillation and type 2 diabetes, but increased genetic susceptibility to higher LDL-C and higher systolic blood pressure. On the multiplicative scale, there was evidence that higher educational attainment increased genetic susceptibility to atrial fibrillation and coronary heart disease, but little evidence of effect modification was found for all other traits considered.

CONCLUSIONS

Educational attainment modifies the genetic susceptibility to some cardiovascular risk factors and diseases. The direction of this effect was mixed across traits considered and differences in associations between the effect of the polygenic score across strata of educational attainment was uniformly small. Therefore, any effect modification by education of genetic susceptibility to cardiovascular risk factors or diseases is unlikely to substantially explain the development of inequalities in cardiovascular risk.

Twelve Variants Polygenic Score for Low-Density Lipoprotein Cholesterol Distribution in a Large Cohort of Patients With Clinically Diagnosed Familial Hypercholesterolemia With or Without Causative Mutations

Background

A significant proportion of individuals clinically diagnosed with familial hypercholesterolemia (FH), but without any disease‐causing mutation, are likely to have polygenic hypercholesterolemia. We evaluated the distribution of a polygenic risk score, consisting of 12 low‐density lipoprotein cholesterol (LDL‐C)‐raising variants (polygenic LDL‐C risk score), in subjects with a clinical diagnosis of FH.

Methods and Results

Within the Lipid Transport Disorders Italian Genetic Network (LIPIGEN) study, 875 patients who were FH‐mutation positive (women, 54.75%; mean age, 42.47±15.00 years) and 644 patients who were FH‐mutation negative (women, 54.21%; mean age, 49.73±13.54 years) were evaluated. Patients who were FH‐mutation negative had lower mean levels of pretreatment LDL‐C than patients who were FH‐mutation positive (217.14±55.49 versus 270.52±68.59 mg/dL, P<0.0001). The mean value (±SD) of the polygenic LDL‐C risk score was 1.00 (±0.18) in patients who were FH‐mutation negative and 0.94 (±0.20) in patients who were FH‐mutation positive (P<0.0001). In the receiver operating characteristic analysis, the area under the curve for recognizing subjects characterized by polygenic hypercholesterolemia was 0.59 (95% CI, 0.56–0.62), with sensitivity and specificity being 78% and 36%, respectively, at 0.905 as a cutoff value. Higher mean polygenic LDL‐C risk score levels were observed among patients who were FH‐mutation negative having pretreatment LDL‐C levels in the range of 150 to 350 mg/dL (150–249 mg/dL: 1.01 versus 0.91, P<0.0001; 250–349 mg/dL: 1.02 versus 0.95, P=0.0001). A positive correlation between polygenic LDL‐C risk score and pretreatment LDL‐C levels was observed among patients with FH independently of the presence of causative mutations.

Conclusions

This analysis confirms the role of polymorphisms in modulating LDL‐C levels, even in patients with genetically confirmed FH. More data are needed to support the use of the polygenic score in routine clinical practice.

Comprehensive Statistical and Bioinformatics Analysis in the Deciphering of Putative Mechanisms by Which Lipid-Associated GWAS Loci Contribute to Coronary Artery Disease

The study was designed to evaluate putative mechanisms by which lipid-associated loci identified by genome-wide association studies (GWAS) are involved in the molecular pathogenesis of coronary artery disease (CAD) using a comprehensive statistical and bioinformatics analysis. A total of 1700 unrelated individuals of Slavic origin from the Central Russia, including 991 CAD patients and 709 healthy controls were examined. Sixteen lipid-associated GWAS loci were selected from European studies and genotyped using the MassArray-4 system. The polymorphisms were associated with plasma lipids such as total cholesterol (rs12328675, rs4846914, rs55730499, and rs838880), LDL-cholesterol (rs3764261, rs55730499, rs1689800, and rs838880), HDL-cholesterol (rs3764261) as well as carotid intima-media thickness/CIMT (rs12328675, rs11220463, and rs1689800). Polymorphisms such as rs4420638 of APOC1 (p = 0.009), rs55730499 of LPA (p = 0.0007), rs3136441 of F2 (p < 0.0001), and rs6065906 of PLTP (p = 0.002) showed significant associations with the risk of CAD, regardless of sex, age, and body mass index. A majority of the observed associations were successfully replicated in large independent cohorts. Bioinformatics analysis allowed establishing (1) phenotype-specific and shared epistatic gene–gene and gene–smoking interactions contributing to all studied cardiovascular phenotypes; (2) lipid-associated GWAS loci might be allele-specific binding sites for transcription factors from gene regulatory networks controlling multifaceted molecular mechanisms of atherosclerosis.

Developmental Angiogenesis Requires the Mitochondrial Phenylalanyl-tRNA Synthetase

Background: Mitochondrial aminoacyl-tRNA synthetases (mtARSs) catalyze the binding of specific amino acids to their cognate tRNAs and play an essential role in the synthesis of proteins encoded by mitochondrial DNA. Defects in mtARSs have been linked to human diseases, but their tissue-specific pathophysiology remains elusive. Here we examined the role of mitochondrial phenylalanyl-tRNA synthetase (FARS2) in developmental angiogenesis and its potential contribution to the pathogenesis of cardiovascular disease.

Methods: Morpholinos were injected into fertilized zebrafish ova to establish an in vivo fars2 knock-down model. A visualization of the vasculature was achieved by using Tg (fli1: EGFP)^y1 transgenic zebrafish. In addition, small interference RNAs (siRNAs) were transferred into human umbilical vein endothelial cells (HUVECs) to establish an in vitro FARS2 knock-down model. Cell motility, proliferation, and tubulogenesis were determined using scratch-wound CCK8, transwell-based migration, and tube formation assays. In addition, mitochondria- and non-mitochondria-related respiration were evaluated using a Seahorse XF24 analyzer and flow cytometry assays. Analyses of the expression levels of transcripts and proteins were performed using qRT-PCR and western blotting, respectively.

Results: The knock-down of fars2 hampered the embryonic development in zebrafish and delayed the formation of the vasculature in Tg (fli1: EGFP)^y1 transgenic zebrafish. In addition, the siRNA-mediated knock-down of FARS2 impaired angiogenesis in HUVECs as indicated by decreased cell motility and tube formation capacity. The knock-down of FARS2 also produced variable decreases in mitochondrial- and non-mitochondrial respiration in HUVECs and disrupted the regulatory pathways of angiogenesis in both HUVECs and zebrafish.

Conclusion: Our current work offers novel insights into angiogenesis defects and cardiovascular diseases induced by FARS2 deficiency.

A genetic sum score of effect alleles associated with serum lipid concentrations interacts with educational attainment

High-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and total cholesterol (TC) levels are influenced by both genes and the environment. The aim was to investigate whether education and income as indicators of socioeconomic position (SEP) interact with lipid-increasing genetic effect allele scores (GES) in a population-based cohort. Using baseline data of 4516 study participants, age- and sex-adjusted linear regression models were fitted to investigate associations between GES and lipids stratified by SEP as well as including GES×SEP interaction terms. In the highest education group compared to the lowest stronger effects per GES standard deviation were observed for HDL-C (2.96 mg/dl [95%-CI: 2.19, 3.83] vs. 2.45 mg/dl [95%-CI: 1.12, 3.72]), LDL-C (6.57 mg/dl [95%-CI: 4.73, 8.37] vs. 2.66 mg/dl [95%-CI: −0.50, 5.76]) and TC (8.06 mg/dl [95%-CI: 6.14, 9.98] vs. 4.37 mg/dl [95%-CI: 0.94, 7.80]). Using the highest education group as reference, interaction terms showed indication of GES by low education interaction for LDL-C (ß_{GES×Education}: −3.87; 95%-CI: −7.47, −0.32), which was slightly attenuated after controlling for GES_LDL-C×Diabetes interaction (ß_{GES×Education}: −3.42; 95%-CI: −6.98, 0.18). The present study showed stronger genetic effects on LDL-C in higher SEP groups and gave indication for a GES_LDL-C×Education interaction, demonstrating the relevance of SEP for the expression of genetic health risks.

Molecular Phylogenetic Analysis of the AIG Family in Vertebrates

Androgen-inducible genes (AIGs), which can be regulated by androgen level, constitute a group of genes characterized by the presence of the AIG/FAR-17a domain in its protein sequence. Previous studies on AIGs demonstrated that one member of the gene family, AIG1, is involved in many biological processes in cancer cell lines and that ADTRP is associated with cardiovascular diseases. It has been shown that the numbers of AIG paralogs in humans, mice, and zebrafish are 2, 2, and 3, respectively, indicating possible gene duplication events during vertebrate evolution. Therefore, classifying subgroups of AIGs and identifying the homologs of each AIG member are important to characterize this novel gene family further. In this study, vertebrate AIGs were phylogenetically grouped into three major clades, ADTRP, AIG1, and AIG-L, with AIG-L also evident in an outgroup consisting of invertebrsate species. In this case, AIG-L, as the ancestral AIG, gave rise to ADTRP and AIG1 after two rounds of whole-genome duplications during vertebrate evolution. Then, the AIG family, which was exposed to purifying forces during evolution, lost or gained some of its members in some species. For example, in eutherians, Neognathae, and Percomorphaceae, AIG-L was lost; in contrast, Salmonidae and Cyprinidae acquired additional AIG copies. In conclusion, this study provides a comprehensive molecular phylogenetic analysis of vertebrate AIGs, which can be employed for future functional characterization of AIGs.

Greater macrovascular and microvascular morbidity from type 2 diabetes in northern compared with southern China: A cross-sectional study

AIMS/INTRODUCTION

There are substantial differences in genes, diet, culture and environment between the northern and southern Chinese populations, which might influence treatment strategy and screening policy. We studied the differences in type 2 diabetes and diabetic complications between northern and southern China.

MATERIALS AND METHODS

We carried out a cross-sectional survey using data from the China Cardiometabolic Registries on blood pressure, blood lipids and blood glucose in 25,398 Chinese type 2 diabetes patients. Macrovascular, microvascular and other complications were collected by self-report or medical records, and then divided into the northern and southern groups by the boundary of the Yangtze River.

RESULTS

Northern patients were younger, and had heavier weight, greater body mass index and waist circumference, higher blood pressure, higher total cholesterol, higher low-density lipoprotein cholesterol, and higher hemoglobin A1C. The prevalence of cardiovascular, cerebrovascular and macrovascular complications were 1.76-fold, 1.24-fold and 1.47-fold more in northern than that in southern Chinese patients. In addition, the prevalence of diabetic nephropathy, retinopathy, neuropathy and microvascular complications in northern Chinese patients also increased. When stratified by age, the difference in both cardiovascular disease and ischemic stroke morbidity became significant, even in the 35-44 years age group.

CONCLUSIONS

More macrovascular and microvascular complications were found in northern compared with southern patients, and the largest difference also appeared in the younger age groups <55 years, which might be meaningful to a screening and treatment strategy according to geographic differences.

Mitochondrial Contact Sites in Inflammation-Induced Cardiovascular Disease

The mitochondrion, the ATP-producing center, is both physically and functionally associated with almost all other organelles in the cell. Mitochondrial-associated membranes (MAMs) are involved in a variety of biological processes, such as lipid exchange, protein transport, mitochondrial fission, mitophagy, and inflammation. Several inflammation-related diseases in the cardiovascular system involve several intracellular events including mitochondrial dysfunction as well as disruption of MAMs. Therefore, an in-depth exploration of the function of MAMs will be of great significance for us to understand the initiation, progression, and clinical complications of cardiovascular disease (CVD). In this review, we summarize the recent advances in our knowledge of MAM regulation and function in CVD-related cells. We discuss the potential roles of MAMs in activating inflammation to influence the development of CVD.

Epigallocatechin gallate suppresses inflammation in human coronary artery endothelial cells by inhibiting NF-κB

The endothelium is a critical regulator of vascular homeostasis, controlling vascular tone and permeability as well as interactions of leukocytes and platelets with blood vessel walls. Consequently, endothelial dysfunction featuring inflammation and reduced vasodilation are considered central to cardiovascular disease (CVD) pathogenesis and have become a therapeutic area of focus. Type II endothelial cell (EC) activation by stress-related stimuli such as tumor necrosis factor-α (TNF-α) initiates the nuclear factor-κB (NF-κB) signaling pathway, a master regulator of inflammatory responses. Because dysregulated NF-κB signaling has been tightly linked to several CVDs, EC-specific inhibition of NF-κB represents an attractive pharmacological strategy. As accumulating evidence highlights the clinical benefits of tea catechin for multiple diseases including CVDs, we sought to determine whether the tea catechin epigallocatechin gallate (EGCG) that displays antioxidative, anti-inflammatory, hypolipidemic, anti-thrombogenic, and anti-hypertensive properties offers protection against CVDs by suppressing the canonical NF-κB pathway. Our findings indicate that EGCG downregulates multiple components of the TNF-α-induced NF-κB signaling pathway and thereby reduces the consequent increase in inflammatory gene transcription and protein expression. Furthermore, EGCG blocked type II EC activation, evidenced by diminished EC leakage and monocyte adhesion in EGCG-treated cells. In summary, our study advances knowledge of EGCG's anti-inflammatory effects on the NF-κB pathway and hence its benefits on endothelial health, supporting its therapeutic potential for CVDs.

Association of +138I/D and Lys198Asn Polymorphisms in the Endothelin-1 Gene with Early Onset of Coronary Artery Disease among the Chinese Han Population

Background

Human endothelin-1 (ET-1) gene polymorphism is closely associated with coronary artery disease (CAD). This study aimed to investigate the association of 2 single-nucleotide polymorphisms (SNPs), +138 I/D and Lys198Asn) of the ET-1 gene,with early onset of CAD in Han Chinese patients. We investigated the effects of Lys198Asn polymorphism on ET-1 protein expression upon stimulation with pro-inflammatory factors.

Material/Methods

Genotyping of the 2 SNPs +138 I/D and Lys198Asn was performed in 88 early-onset CAD patients (≤55 years for males; ≤60 years for females) and 52 healthy control participants using a polymerase chain reaction direct sequencing method. The association of the 2 SNPs was analyzed with SPSS 17.0 software. Western blotting was performed to assess the effects of ET-1 polymorphisms on ET-1 protein expression upon tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and lipopolysaccharide (LPS) stimulation in HEK-293T cells.

Results

Fisher’s exact test showed that the T allele (odds ratio [OR]=3.38, P=0.02) and GT/TT genotype (OR=3.76, P=0.02) of the ET-1 gene Lys198Asn were associated with increased early-onset CAD risk. Multivariate logistic regression analysis showed smoking was the single independent variable related to early-onset CAD (P<0.05). An increase of ET-1 protein levels in cells transfected with Asn198 plasmid was seen upon TNF-α or IL-6 stimulation.

Conclusions

T allele frequency in Lys198Asn loci might be associated with the pathogenesis of early-onset CAD. T-variant might contribute to early-onset CAD by upregulating ET-1 expression upon inflammatory cytokines stimulation, and smokers who have the T allele might be vulnerable to CAD in the Chinese population.

A coronary artery disease-associated tRNAThr mutation altered mitochondrial function, apoptosis and angiogenesis

The tissue specificity of mitochondrial tRNA mutations remains largely elusive. In this study, we demonstrated the deleterious effects of tRNAThr 15927G>A mutation that contributed to pathogenesis of coronary artery disease. The m.15927G>A mutation abolished the highly conserved base-pairing (28C-42G) of anticodon stem of tRNAThr. Using molecular dynamics simulations, we showed that the m.15927G>A mutation caused unstable tRNAThr structure, supported by decreased melting temperature and slower electrophoretic mobility of mutated tRNA. Using cybrids constructed by transferring mitochondria from a Chinese family carrying the m.15927G>A mutation and a control into mitochondrial DNA (mtDNA)-less human umbilical vein endothelial cells, we demonstrated that the m.15927G>A mutation caused significantly decreased efficiency in aminoacylation and steady-state levels of tRNAThr. The aberrant tRNAThr metabolism yielded variable decreases in mtDNA-encoded polypeptides, respiratory deficiency, diminished membrane potential and increased the production of reactive oxygen species. The m.15927G>A mutation promoted the apoptosis, evidenced by elevated release of cytochrome c into cytosol and increased levels of apoptosis-activated proteins: caspases 3, 7, 9 and PARP. Moreover, the lower wound healing cells and perturbed tube formation were observed in mutant cybrids, indicating altered angiogenesis. Our findings provide new insights into the pathophysiology of coronary artery disease, which is manifested by tRNAThr mutation-induced alterations.

Impact of gender and age on the association of the BUD13-ZNF259 rs964184 polymorphism with coronary heart disease

OBJECTIVE

Coronary heart disease (CHD) is the most common cause of death worldwide. This study aimed to validate the association of the rs964184 polymorphism with the CHD risk and included 874 CHD patients and 776 controls.

METHODS

rs964184 polymorphism genotyping was performed using Tm-shift polymerase chain reaction.

RESULTS

A strong association of the rs964184 polymorphism with CHD was found (genotype: X²=14.365, p=0.001; allele: X²=14.191, p=1.67x10^-4; power=0.965). Gender analysis revealed a significant association only in males (genotype: X²=12.387, p=0.002; allele: X²=12.404, p=4.32x10^-4; OR=1.467, 95% CI=1.185-1.817, power=0.945). Age and gender analyses revealed significant associations of the rs964184 polymorphism with CHD in males between the ages of 55 and 65 years (genotype: X²=10.070, p=0.007; allele: X²=10.077, p=0.002; OR=1.706, 95% CI=1.224-2.377, power=0.996) and in females older than 65 years (genotype: X²=9.462, p=0.009; allele: X²=9.560, p=0.002; OR=2.112, 95% CI=1.308-3.412, power=0.994). Further subgroup analysis suggested that rs964184 genotypes were significantly associated with TG levels in the patients (r=0.191, adjusted p=1.05x10^-5) and controls (r=0.101, adjusted p=0.026).

CONCLUSION

Our results indicate that both gender and age have great impacts on the association of the rs964184 polymorphism with CHD among Chinese.

Racial differences in family health history knowledge of type 2 diabetes: exploring the role of interpersonal mechanisms

Collecting complete and accurate family health history is critical to preventing type 2 diabetes. Whether there are any racial difference in family health history knowledge of type 2 diabetes and whether such differences are related to interpersonal mechanisms remain unclear. We seek to identify the interpersonal mechanisms that give rise to discrepancies in family health history knowledge of type 2 diabetes in families of different racial backgrounds. We analyze informant-dyad consensus with respect to shared family history of type 2 diabetes in 127 informants of 45 families in the greater Cincinnati area (white: 28 families, 78 informants; black/African-American: 17 families, 49 informants). We first document a difference in informant-dyad consensus by race and then test whether this difference can be explained by interpersonal ties, particularly health communication. Compared with their white counterparts, dyads in families of black/African-American background are more likely to have an uneven distribution of knowledge, with one informant knowing and the other not knowing his/her family health history. The racial difference is explained by dyads in families of black/African-American background having fewer reciprocal health communication ties. While associated with informant-dyad consensus, education, kinship ties, and closeness ties do not account for the observed racial difference. Activating health communication is a key to improving family health history knowledge, especially in families of black/African-American background. Researchers and clinicians should leverage communication ties in the family network for better collection and utilization of family health history in preventive services.

Development, validation and application of a novel HPLC-MS/MS method for the quantification of atorvastatin, bisoprolol and clopidogrel in a large cardiovascular patient cohort

Cardiovascular disease is a leading cause of morbidity, mortality, and healthcare expenditure worldwide. Importantly, there is interindividual variation in response to cardiovascular medications, leading to variable efficacy and adverse events. Therefore a rapid, selective, sensitive and reproducible multi-analyte HPLC-MS/MS assay for the quantification in human plasma of atorvastatin, its major metabolites 2-hydroxyatorvastatin, atorvastatin lactone and 2-hydroxyatorvastatin lactone, plus bisoprolol and clopidogrel-carboxylic acid has been developed, fully validated, and applied to a large patient study. Fifty microliter plasma samples were extracted with a simple protein precipitation procedure involving acetonitrile with acetic acid (0.1%, v/v). Chromatographic separation was via a 2.7 μm Halo C18 (50 × 2.1 mm ID, 90 Å) column and gradient elution at a flow rate of 500 μL/min consisting of a mobile phase of water (A) and acetonitrile (B), each containing 0.1% formic acid (v/v), over a 6.0 min run time. The six analytes and their corresponding six deuterated internal standards underwent positive ion electrospray ionisation and were detected with multiple reaction monitoring. The developed method was fully validated with acceptable selectivity, carryover, dilution integrity, and within-run and between-run accuracy and precision. Mean extraction recovery for the analytes was 92.7-108.5%, and internal standard-normalised matrix effects had acceptable precision (coefficients of variation 2.2-12.3%). Moreover, all analytes were stable under the tested conditions. Atorvastatin lactone to acid interconversion was assessed and recommendations for its minimisation are made. The validated assay was successfully applied to analyse 1279 samples from 1024 patients recruited to a cardiovascular secondary prevention prospective study.

Interactions among genes involved in reverse cholesterol transport and in the response to environmental factors in dyslipidemia in subjects from the Xinjiang rural area

Gene-gene and gene-environment interactions may be partially responsible for dyslipidemia, but studies investigating interactions in the reverse cholesterol transport system (RCT) are limited. We explored these interactions in a Xinjiang rural population by genotyping five SNPs using SNPShot technique in APOA1, ABCA1, and LCAT, which are involved in the RCT (690 patients, 743 controls). We conducted unconditional logistical regression analysis to evaluate associations and generalized multifactor dimensionality reduction to evaluate interactions. Results revealed significant differences in rs670 and rs2292318 allele frequencies between cases and controls (P<0.025). rs670 G allele carriers were more likely to develop dyslipidemia than A allele carriers (OR = 1.315, OR 95% CI: 1.067–2.620; P = 0.010). rs2292318 T allele carriers were more likely to develop dyslipidemia than A allele carriers (OR = 1.264, OR 95% CI: 1.037–1.541; P = 0.020). Gene-gene interaction model APOA1rs670-ABCA1rs1800976-ABCA1rs4149313-LCATrs1109166 (P = 0.0107) and gene-environment interaction model ABCA1rs1800976-ABCA1rs4149313-LCATrs1109166-obesity-smoking were optimal dyslipidemia predictors (P = 0.0107) and can interact (4). Differences in A-C-A-C-A and G-G-G-T-G haplotype frequencies were observed (P<0.05). Serum lipid profiles could be partly attributed to RCT gene polymorphisms. Thus, dyslipidemia is influenced by APOA1, ABCA1, LCAT, environmental factors, and their interactions.

2015 Health Survey of São Paulo with Focus in Nutrition: Rationale, Design, and Procedures

This paper describes the design, sampling methods, and data collection procedures, with particular focus on dietary data, used for the 2015 Health Survey of São Paulo (Inquérito de Saúde de São Paulo, 2015 ISA-Capital) with Focus in Nutrition Study (2015 ISA-Nutrition). The ISA is a household cross-sectional, population-based survey that uses complex, stratified, multistage sampling to create a representative sample of residents from urban São Paulo, Brazil. The 2015 ISA-Nutrition comprised a sub-sample of the 2015 ISA-Capital and intended to include 300 adolescents (aged 12 to 19 years), 300 adults (aged 20 to 59 years), and 300 older adults (aged ≥60 years). From February 2015 to February 2016, 1737 individuals answered the first 24-h dietary recall (24HR), and 901 individuals consented to have their blood sample collected, to undergo anthropometric and blood pressure assessment, and to answer the second 24HR. The 2015 ISA-Nutrition aims to evaluate lifestyle-related modifiable factors in São Paulo's residents, as well as their association with biochemical and genetic markers, and environmental aspects related to cardiometabolic risk factors. This paper concludes that 2015 ISA-Nutrition may provide valuable insights into the cardiometabolic risk factors in a big city in an upper middle-income country and contribute to the formulation of health and nutritional policies.

NPR-C gene polymorphism is associated with increased susceptibility to coronary artery disease in Chinese Han population: a multicenter study

To find a new locus that confers significant susceptibility to CAD in Chinese Han population, a genome-wide association study in 200 “extreme individuals” from a Shandong cohort and a pathway-based candidate gene study from a Shanghai cohort (293 CAD/293 controls) were simultaneously performed. Amongst them, 13 SNPs associated with CAD were selected to conduct validation and replication studies in additional 3363 CAD patients and 3148 controls. A novel locus rs700926 in natriuretic peptide receptor C (NPR-C) was identified in Shandong and Hubei cohorts. Then rs700926 and other nine tag SNPs were genotyped in four geographically different populations (Shandong, Shaanxi, Hubei and Sichuan cohorts), and 6 SNPs (rs700926, rs1833529, rs2270915, rs17541471, rs3792758 and rs696831) showed stronger association with CAD, regardless of single or combined analysis. We further genotyped rs2270915 and 10 additional tag SNPs in a central China cohort and identified rs12697273 and rs10066436 as the loci associated with CAD. All these positive associations remained significant after adjustment for traditional risk factors of CAD. NPR-C gene SNPs significantly contribute to CAD susceptibility in the Chinese Han population.

Association of nitric oxide synthase 3 gene polymorphism with the risk of type 2 diabetes

Type-2 diabetes (T2D) is a multifactorial (environmental and genetic factors) and global epidemic disease with an estimated high prevalence worldwide. Studies have indicated that nitric oxide synthase 3 (NOS3) has several important roles in the pathogenesis of T2D. The present study aims to investigate the association between NOS3 rs1800779(A/G) and T2D in an Iranian sample population. A case-control study was conducted on 250 T2D patients and 250 healthy control subjects (HCs). Genotyping of the rs1800779(A/G) variant was conducted using a Tetra-Amplification Refractory Mutation System polymerase chain reaction. The frequencies of genotypes AA, AG and GG polymorphisms were 56.8, 39.2 and 4% in the T2D group, and 42.8, 56 and 1.2% in the HCs group, respectively. The frequency of the minor (G) allele was 23.6% in the T2D group and 29.2% in the HCs group. The genotype frequencies of the rs1800779(A/G) variant demonstrated statistically significant differences between T2D and controls in a codominant model (AG vs. AA, OR=0.527, 95% CI=0.368-0.756, P<0.001) and dominant model (AG+GG vs. AA, OR=0.569, 95% CI=0.399-0.811, P=0.002). There was no significant association between clinical and demographic characteristics and the NOS3 rs1800779(A/G) polymorphism in dominant status (P>0.05). The dominant model and AG genotype of NOS3 rs1800779(A/G) polymorphism may had a protective effect on T2D of Iranian population.

Apolipoprotein C-I Polymorphism and Its Association with Serum Lipid Levels and Longevity in the Bama Population

This study aims to determine the association between the apolipoprotein C-I polymorphism and the longevity and genetic variants in ApoC-I that can influence the serum lipid levels in Bama. ApoC-I genotypes were determined by Taqman single nucleotide polymorphism (SNP) genotyping assays in 178 long-lived inhabitants (longevity group aged from 90 to 110 years), 147 healthy controls (Control 1 group aged from 40 to 79 years old) from Bama County, and 190 healthy controls (Control 2 group aged from 40 to 79 years old) from Nandan County without a family history of longevity. Statistical analysis was conducted using SPSS 16.0. All genotype distributions of rs584007 and rs4420638 were consistent with the Hardy-Weinberg equilibrium (p > 0.05). Significant differences were observed in the frequencies of the three genotypes (GG, AG, and AA) among the longevity and the two control groups (χ² = 11.238, p = 0.024) for rs584007. No significant differences were observed in the frequencies of the three genotypes (GG, AG, and AA) among the longevity and the two control groups (χ² = 4.587, p = 0.318) for rs4420638. The levels of total cholesterol (TC), triglycerides (TG), high-density lipoprotein-cholesterol (HDL-c), and low-density lipoprotein-cholesterol (LDL-c) were not different among the three genotypes of rs584007 in the three groups. The levels of HDL-c for GG, AG, and AA were significantly different (the highest being in the longevity group), while the levels of TG for AA and AG genotypes (the lowest being in the longevity group) and the levels of LDL-c for AG were significantly different (p < 0.05) among the three groups for rs584007. The levels of TG and HDL-c were significantly different among the three rs4420638 genotypes in the longevity group. The levels of TC for GG, AG, and AA were significantly different in the Control 2 group, while the levels of TG and HDL-c for AA and AG genotypes were significantly different (p < 0.05) among the three groups for rs4420638. The level of HDL-c was highest in the longevity group for AA and AG genotypes, and the level of TG was highest in the Control 2 group for rs4420638. Serum lipid parameters were related to environmental factors, including age, gender, BMI, DBP, SBP, rs4420638, and rs584007. The ApoC-I polymorphism might be one of the genetic factors of longevity in Bama. The ApoC-I rs4420638 and rs584007 SNPs are associated with serum TG and HDL-c levels in the longevous population.

Usefulness of Maintaining a Normal Electrocardiogram Over Time for Predicting Cardiovascular Health

We hypothesized that maintaining a normal electrocardiogram (ECG) status over time is associated with low cardiovascular (CV) disease in a dose-response fashion and subsequently could be used to monitor programs aimed at promoting CV health. This analysis included 4,856 CV disease-free participants from the Atherosclerosis Risk in Communities study who had a normal ECG at baseline (1987 to 1989) and complete electrocardiographic data in subsequent 3 visits (1990 to 1992, 1993 to 1995, and 1996 to 1998). Participants were classified based on maintaining their normal ECG status during these 4 visits into "maintained," "not maintained," or "inconsistent" normal ECG status as defined by the Minnesota ECG classification. CV disease events (coronary heart disease, heart failure, and stroke) were adjudicated from Atherosclerosis Risk in Communities visit-4 through 2010. Over a median follow-up of 13.2 years, 885 CV disease events occurred. The incidence rate of CV disease events was lowest among study participants who maintained a normal ECG status, followed by those with an inconsistent pattern, and then those who did not maintain their normal ECG status (trend p value <0.001). Similarly, the greater the number of visits with a normal ECG status, the lower was the incidence rate of CV disease events (trend p value <0.001). Maintaining (vs not maintaining) a normal ECG status was associated with a lower risk of CV disease, which was lower than that observed in those with inconsistent normal ECG pattern (trend p value <0.01). In conclusion, maintaining a normal ECG status over time is associated with low risk of CV disease in a dose-response fashion, suggesting its potential use as a monitoring tool for programs promoting CV health.

Rationale, design, methods and baseline characteristics of the Asklepios Study

The Asklepios Study is a longitudinal population study focusing on the interplay between ageing, cardiovascular haemodynamics and inflammation in (preclinical) cardiovascular disease. The 2524 participants (1301 women) are a representative cohort of 35-55-year-old individuals, free from overt cardiovascular disease at study initiation, randomly sampled from the twinned Belgian communities of Erpe-Mere and Nieuwerkerken. Baseline examinations (all single-observer, single-device, single-site, single 2-year consecutive timeframe) include: questionnaires, conventional risk factors and biochemistry. Additional phenotypes under study include: (a) vascular structure and function: carotid and femoral atherosclerosis (intima-media thickness, plaque), arterial distension and pressure curves (brachial, carotid, femoral; wall-tracking and applanation tonometry); (b) cardiac structure and function. A novel aspect of the study is 'integrated' non-invasive biomechanical assessment of cardiac, arterial and ventriculovascular function through a combination of modeling, fundamental hydraulical measurements and system identification techniques. Integrated phenotypes result from combining at least two sets of curves (flow/pressure/distension). The value of this 'integrated' haemodynamic phenotype in the detection, prediction and prevention of clinical cardiovascular pathology (atherosclerosis progression, atherothrombosis, development of heart failure) will be tested. A second novel aspect is the systematic determination of peripheral blood leukocyte telomere length as a marker for biological ageing. During follow-up, baseline examinations will be repeated and the incidence of cardiovascular events will be monitored. Sex-specific baseline risk factor and biochemical data are provided in the current analyses. The primary aim is to build a combined dataset that will act as a tool to answer a cluster of questions about ageing, haemodynamics and the emergence of cardiovascular disease, especially the incidence of atherothrombotic events and the development of adverse haemodynamic profiles (arterial stiffening, heart failure). The study will reassess current risk factors and provide a long-term base for the detection of novel (epi)genetic and non-genetic risk factors and for more performant risk stratification modalities. Within these broader goals, a constant will be to strive towards more fundamental mechanistic-haemodynamic insights into cardiovascular disease processes.

Association of single nucleotide polymorphism rs2076185 in chromosome 6P24.1 with premature coronary artery diseases in Chinese Han population

OBJECTIVES

To study the association of single nucleotide polymorphism (SNP) rs2076185 in chromosome 6p24.1 with the premature coronary artery diseases (PCAD) in Chinese Han population.

METHODS

A total of 1382 patients were divided into the PCAD group and the control group based on their coronary arteriography (CAG) results. Their SNP rs2076185 were analyzed by the mass-spectrometry. Their allele and genotype frequency in Hardy-Weinberg equilibrium were calculated for assessment. Logistic regression was employed to remove confounding factors and correlate SNP rs2076185 with PCAD.

RESULTS

The allele and genotype frequencies of the control group were in Hardy-Weinberg equilibrium (P > 0.05). The frequencies of allele G of rs2076185 were 54.2% in the PCAD group and 49.5% in the control group. The difference was significant (P = 0.042). The genotype distribution of rs2076185 of the two groups was also significantly different. The univariate analysis showed that the rs2076185 polymorphisms were associated with the PCAD only in the additive model (OR: 0.828, 95% CI: 0.711-0.964, P = 0.014), and in the dominant model (OR: 0.753, 95% CI: 0.591-0.958, P = 0.021). After removing the confounding variables, the rs2076185 polymorphisms was associated with PCAD in the additive model (OR: 0.775, 95% CI: 0.648-0.928, P = 0.005), in the dominant model (OR: 0.698, 95% CI: 0.527-0.925, P = 0.012), and in the recessive model (OR: 0.804, 95% CI: 0.538-0.983, P = 0.038).

CONCLUSION

Allele G of rs2076185 reduces the PCAD risks in Chinese Han population, therefore it could be a coronary artery diseases protective factor in Chinese Han population.

Oats-From Farm to Fork

Oats have a long history of use as human food and animal feed. From its origins in the Fertile Crescent, the oat has adapted to a wide range of climatic conditions and geographic regions. Its unique macro-, micro-, and phytonutrient composition, high nutritional value, and relatively low agricultural input requirements makes oats unique among cereal crops. The health benefits of the oats are becoming well established. While the connection between oat β-glucan fiber in reducing the risk of cardiovascular disease and controlling glycemia have been unequivocally established, other potential benefits including modulation of intestinal microbiota and inflammation continue to be explored. Advances in food technology are continuing to expand the diversity of oat-based foods, creating opportunities to deliver the health benefits of oats to a larger segment of the population.

Association of Mbo I-RFLP at the Renin Locus (rs2368564) with Essential Hypertension

Several lines of experimental and clinical evidence have alluded a pivotal role of renin in blood pressure homeostasis and therefore a relevance of molecular variants of the renin gene and essential hypertension have been speculated. This study was designed to evaluate the pattern, alliance and risk of renin Mbo I (10631A>G; rs2368564) polymorphism at the locus intron 9 for a possible role in modulating essential hypertension in adult population from Gujarat (India). A total of 257 consecutively enrolled essential hypertensive patients and 270 controls were genotyped using polymerase chain reaction-restriction fragment length polymorphism method for the selected marker. Suitable descriptive statistics was used for different variables. Genotypic (x(2) 10.43, p 0.0054) and allelic (x(2) 11.46, p 0.0007) distribution of this SNP displayed significant differences between cases and controls with an increased frequency of the A allele (x(2) 6.275; p 0.0122) and A/A geno-type (x(2) 8.247; p 0.0041) in hypertensive individuals. However, it showed no deviation from Hardy-Weinberg equilibrium in either affected or control group. A significant association was found in the A/A variant of rs2368564 with essential hypertension (p 0.0032), along with a statistically significant increase in odds of hypertension (OR 1.69; CI 1.46-2.28; p 0.02), even after confounding factors were adjusted in multiple logistic regression analysis and is substantiated by inter-genotypic variations in the mean systolic and diastolic blood pressure in patients. In conclusion, renin 10631A>G gene mutation at the ninth intron play critical roles in BP (dys)regulation and can be implicated in an individual's susceptibility for hypertension.

Dysfunctional High-Density Lipoprotein: An Innovative Target for Proteomics and Lipidomics

High-Density Lipoprotein-Cholesterol (HDL-C) is regarded as an important protective factor against cardiovascular disease, with abundant evidence of an inverse relationship between its serum levels and risk of cardiovascular disease, as well as various antiatherogenic, antioxidant, and anti-inflammatory properties. Nevertheless, observations of hereditary syndromes featuring scant HDL-C concentration in absence of premature atherosclerotic disease suggest HDL-C levels may not be the best predictor of cardiovascular disease. Indeed, the beneficial effects of HDL may not depend solely on their concentration, but also on their quality. Distinct subfractions of this lipoprotein appear to be constituted by specific protein-lipid conglomerates necessary for different physiologic and pathophysiologic functions. However, in a chronic inflammatory microenvironment, diverse components of the HDL proteome and lipid core suffer alterations, which propel a shift towards a dysfunctional state, where HDL-C becomes proatherogenic, prooxidant, and proinflammatory. This heterogeneity highlights the need for further specialized molecular studies in this aspect, in order to achieve a better understanding of this dysfunctional state; with an emphasis on the potential role for proteomics and lipidomics as valuable methods in the search of novel therapeutic approaches for cardiovascular disease.

Common Variants in Promoter of ADTRP Associate with Early-Onset Coronary Artery Disease in a Southern Han Chinese Population

The first genome-wide association study for coronary artery disease (CAD) in the Han Chinese population, we reported recently, had identified rs6903956 in gene ADTRP on chromosome 6p24.1 as a novel susceptibility locus for CAD. The risk allele of rs6903956 was associated with decreased mRNA expression of ADTRP. To further study the correlation of ADTRP expression and CAD, in this study we evaluated the associations of eight common variants in the expression-regulating regions of ADTRP with CAD in the Southern Han Chinese population. Rs169790 in 3’UTR, rs2076189 in 5’UTR, four SNPs (rs2076188, rs7753407, rs11966356 and rs1018383) in promoter, and two SNPs (rs3734273, rs80355771) in the last intron of ADTRP were genotyped in 1716 CAD patients and 1572 controls. The correlations between these loci and total or early-onset CAD were investigated. None of these loci was discovered to associate with total CAD (P > 0.05). However, with early-onset CAD, significant both allelic and genotypic associations of rs7753407, rs11966356 and rs1018383 were identified, after adjustment for risk factors of age, gender, hypertension, diabetes, lipid profiles and smoking (adjusted P < 0.05). A haplotype AGCG (constructed by rs2076188, rs7753407, rs11966356 and rs1018383) was identified to protect subjects from early-onset CAD (OR = 0.332, 95% CI = 0.105–0.879, adjusted P = 0.010). Real-time quantitative reverse transcription polymerase chain reaction assay showed that the risk alleles of the associated loci were significantly associated with decreased expression of ADTRP mRNA. Moreover, the average level of ADTRP mRNA expression in early-onset CAD cases was significantly lower than that in controls. Our results provide new evidence supporting the association of ADTRP with the pathogenesis of early-onset CAD.

Lymphoblastoid cell lines reveal associations of adult DNA methylation with childhood and current adversity that are distinct from whole blood associations

BACKGROUND

Some cohort studies bank lymphoblastoid cell lines (LCLs) as a renewable source of participant DNA. However, although LCL DNA has proved valuable for genetic studies, its utility in epigenetic epidemiology research is unknown.

METHODS

To assess whether LCL DNA can be used for life-course environmental epigenomics, we carried out a pilot methylomic study (using the Illumina Infinium Human Methylation 450 BeadChip) of nil-passage, Epstein-Barr virus (EBV)-transformed LCLs (n = 42) and 28 matched whole-blood (WB) samples. These were from adult male participants of the British 1958 birth cohort, selected for extremes of social economic position (SEP) in childhood and adulthood, with additional information available on childhood abuse and prenatal tobacco exposure.

RESULTS

We identified a small number of weak associations between these exposures and methylation levels of both individual CpG sites and genomic regions in WB and LCLs. However, only one of the regional, and none of the individual CpG site associations were common to both sample types. The lack of overlap between the associations detected in LCL compared with those found in WB could either be due to the EBV-transformation process, or to the fact that, unlike WB, LCLs are essentially a single (CD19+) cell type. We provide evidence that the latter is the more potent explanation, by showing that CpG sites known to be differentially methylated between different types of blood cell have significantly lower correlations (R = 0.11) than average (R = 0.2) between WB and LCLs in our datasets, whereas sites known to be affected by EBV-transformation have significantly higher correlations (R = 0.3).

CONCLUSIONS

This small pilot study suggests that the DNA methylation profile of LCLs is more closely related to that of B cells than WB and, additionally, that LCLs may nevertheless be useful for life-course environmental epigenomics.

Subgroups at high risk for ischaemic heart disease:identification and validation in 67 000 individuals from the general population

BACKGROUND

The aetiology of ischaemic heart disease (IHD) is complex and is influenced by a spectrum of environmental factors and susceptibility genes. Traditional statistical modelling considers such factors to act independently in an additive manner. The Patient Rule-Induction Method (PRIM) is a multi-model building strategy for evaluating risk attributable to context-dependent gene and environmental effects.

METHODS

PRIM was applied to 9073 participants from the prospective Copenhagen City Heart Study (CCHS). Gender-specific cumulative incidences were estimated for subgroups defined by categories of age, smoking, hypertension, diabetes, body mass index, total cholesterol, high-density lipoprotein cholesterol and triglycerides and by 94 single nucleotide variants (SNVs).Cumulative incidences for subgroups were validated using an independently ascertained sample of 58 240 participants from the Copenhagen General Population Study (CGPS).

RESULTS

In the CCHS the overall cumulative incidences were 0.17 in women and 0.21 in men. PRIM identified six and four mutually exclusive subgroups in women and men, respectively, with cumulative incidences of IHD ranging from 0.02 to 0.34. Cumulative incidences of IHD generated by PRIM in the CCHS were validated in four of the six subgroups of women and two of the four subgroups of men in the CGPS.

CONCLUSIONS

PRIM identified high-risk subgroups characterized by specific contexts of selected values of traditional risk factors and genetic variants. These subgroups were validated in an independently ascertained cohort study. Thus, a multi-model strategy may identify groups of individuals with substantially higher risk of IHD than the overall risk for the general population.

Multivariate dimensionality reduction approaches to identify gene-gene and gene-environment interactions underlying multiple complex traits

The elusive but ubiquitous multifactor interactions represent a stumbling block that urgently needs to be removed in searching for determinants involved in human complex diseases. The dimensionality reduction approaches are a promising tool for this task. Many complex diseases exhibit composite syndromes required to be measured in a cluster of clinical traits with varying correlations and/or are inherently longitudinal in nature (changing over time and measured dynamically at multiple time points). A multivariate approach for detecting interactions is thus greatly needed on the purposes of handling a multifaceted phenotype and longitudinal data, as well as improving statistical power for multiple significance testing via a two-stage testing procedure that involves a multivariate analysis for grouped phenotypes followed by univariate analysis for the phenotypes in the significant group(s). In this article, we propose a multivariate extension of generalized multifactor dimensionality reduction (GMDR) based on multivariate generalized linear, multivariate quasi-likelihood and generalized estimating equations models. Simulations and real data analysis for the cohort from the Study of Addiction: Genetics and Environment are performed to investigate the properties and performance of the proposed method, as compared with the univariate method. The results suggest that the proposed multivariate GMDR substantially boosts statistical power.

Validated context-dependent associations of coronary heart disease risk with genotype variation in the chromosome 9p21 region: the Atherosclerosis Risk in Communities study

Markers of the chromosome 9p21 region are regarded as the strongest and most reliably significant genome-wide association study (GWAS) signals for Coronary heart disease (CHD) risk; this was recently confirmed by the CARDIoGRAMplusC4D Consortium meta-analysis. However, while these associations are significant at the population level, they may not be clinically relevant predictors of risk for all individuals. We describe here the results of a study designed to address the question: What is the contribution of context defined by traditional risk factors in determining the utility of DNA sequence variations marking the 9p21 region for explaining variation in CHD risk? We analyzed a sample of 7,589 (3,869 females and 3,720 males) European American participants of the Atherosclerosis Risk in Communities study. We confirmed CHD-SNP genotype associations for two 9p21 region marker SNPs previously identified by the CARDIoGRAMplusC4D Consortium study, of which ARIC was a part. We then tested each marker SNP genotype effect on prediction of CHD within sub-groups of the ARIC sample defined by traditional CHD risk factors by applying a novel multi-model strategy, PRIM. We observed that the effects of SNP genotypes in the 9p21 region were strongest in a sub-group of hypertensives. We subsequently validated the effect of the region in an independent sample from the Copenhagen City Heart Study. Our study suggests that marker SNPs identified as predictors of CHD risk in large population based GWAS may have their greatest utility in explaining risk of disease in particular sub-groups characterized by biological and environmental effects measured by the traditional CHD risk factors.

Arguments for the sake of endophenotypes: examining common misconceptions about the use of endophenotypes in psychiatric genetics

Endophenotypes are measurable biomarkers that are correlated with an illness, at least in part, because of shared underlying genetic influences. Endophenotypes may improve our power to detect genes influencing risk of illness by being genetically simpler, closer to the level of gene action, and with larger genetic effect sizes or by providing added statistical power through their ability to quantitatively rank people within diagnostic categories. Furthermore, they also provide insight into the mechanisms underlying illness and will be valuable in developing biologically-based nosologies, through efforts such as RDoC, that seek to explain both the heterogeneity within current diagnostic categories and the overlapping clinical features between them. While neuroimaging, electrophysiological, and cognitive measures are currently most used in psychiatric genetic studies, researchers currently are attempting to identify candidate endophenotypes that are less genetically complex and potentially closer to the level of gene action, such as transcriptomic and proteomic phenotypes. Sifting through tens of thousands of such measures requires automated, high-throughput ways of assessing, and ranking potential endophenotypes, such as the Endophenotype Ranking Value. However, despite the potential utility of endophenotypes for gene characterization and discovery, there is considerable resistance to endophenotypic approaches in psychiatry. In this review, we address and clarify some of the common issues associated with the usage of endophenotypes in the psychiatric genetics community.

Pattern of cardiovascular admissions at Nnamdi Azikiwe University Teaching Hospital Nnewi, South East Nigeria

INTRODUCTION

Cardiovascular disease (CVD) is one of the top killer diseases in the world sparing neither developed or developing countries. The study was carried out to determine the pattern of cardiovascular admissions at Nnamdi Azikiwe University Teaching Hospital Nnewi South East Nigeria.

METHODS

The study was a retrospective study covering the period January 2007 to December 2009. SPSS version 13 software was used to analyze data.

RESULTS

537 (15%) patients were admitted into the study out of 3546 patients {females 1756 and 1790} admitted into medical wards. 322 (60%) of study population were males and 215 (40%) females. 359(67.5%) were discharged, 170 (32%) died and 8 (0.5%) were discharged against medical advice. The majority of the deaths 105(61.8%), were in patients with CVA. Most of the deaths (111 or 65.3%) occurred within the first seven days of admission. The mean age of the population was 60.7 years ±15.9 with a range of 18 to 110 years. The length of stay in hospital ranged between 1 and 140 days with a mean of 13.5 ± 13.9 days and a median of 10 days. 33 of the subjects were single, 406 were married, 94 were widowed (11 males and 83 females) and 4 were divorced. 46.7% (251) were admitted for CVA and 30.9% (166) for heart failure. Cardiomyopathy/valvular heart diseases (clinical diagnosis due to absence of echocardiography) constituted 3.9%, hypertension 20.5% and pre-existing hypertension with uremia 1.9%.

CONCLUSION

The study has shown that cardiovascular disease contributed significantly to medical admissions the elderly accounting for a significant proportion. There is thus the need for intensification of primary preventive strategies for cardiovascular diseases.

Mitochondrial tRNA variants in Chinese subjects with coronary heart disease

BACKGROUND

Coronary heart disease is the leading cause of death worldwide. Mitochondrial genetic determinants for the development of this disorder remain less explored.

METHODS AND RESULTS

We performed a clinical and genetic evaluation and mutational screening of 22 mitochondrial tRNA genes in a cohort of 80 genetically unrelated Han Chinese subjects and 125 members of 4 families with coronary heart disease and 512 Chinese control subjects. This analysis identified 16 nucleotide changes among 9 tRNA genes. Of these, the T5592C mutation creates a highly conservative base pairing (5G-68C) on the acceptor stem of tRNA(Gln), whereas the G15927A mutation destabilizes a highly conserved base pairing (28C-42G) in the anticodon stem of tRNA(Thr). However, the other tRNA variants were polymorphisms. The pedigrees of BJH24 carrying the T5592C mutation, BJH15, and BJH45 harboring the G15927A mutation exhibited maternal transmission of coronary heart disease. Sequence analysis of their mitochondrial genomes revealed the presence of T5592C or G15927A mutation but the absence of other functionally significant mutations in all matrilineal relatives of these families.

CONCLUSIONS

Our previous observations showed that altered structures of tRNAs by these mtDNA mutations caused mitochondrial dysfunction. These may be the first evidence that mtDNA mutations increase the risk of coronary heart disease. Our findings may provide new insights into the pathophysiology of this disorder.

Opportunity for selection in human health

Natural selection defined by differential survival and reproduction of individuals in populations is influenced by genetic, developmental, and environmental factors operating at every age and stage in human life history: generation of gametes, conception, birth, maturation, reproduction, senescence, and death. Biological systems are built upon a hierarchical organization nesting subcellular organelles, cells, tissues, and organs within individuals, individuals within families, and families within populations, and the latter among other populations. Natural selection often acts simultaneously at more than one level of biological organization and on specific traits, which we define as multilevel selection. Under this model, the individual is a fundamental unit of biological organization and also of selection, imbedded in a larger evolutionary context, just as it is a unit of medical intervention imbedded in larger biological, cultural, and environmental contexts. Here, we view human health and life span as necessary consequences of natural selection, operating at all levels and phases of biological hierarchy in human life history as well as in sociological and environmental milieu. An understanding of the spectrum of opportunities for natural selection will help us develop novel approaches to improving healthy life span through specific and global interventions that simultaneously focus on multiple levels of biological organization. Indeed, many opportunities exist to apply multilevel selection models employed in evolutionary biology and biodemography to improving human health at all hierarchical levels. Multilevel selection perspective provides a rational theoretical foundation for a synthesis of medicine and evolution that could lead to discovering effective predictive, preventive, palliative, potentially curative, and individualized approaches in medicine and in global health programs.

Genome-wide association study of gene by smoking interactions in coronary artery calcification

Many GWAS have identified novel loci associated with common diseases, but have focused only on main effects of individual genetic variants rather than interactions with environmental factors (GxE). Identification of GxE interactions is particularly important for coronary heart disease (CHD), a major preventable source of morbidity and mortality with strong non-genetic risk factors. Atherosclerosis is the major cause of CHD, and coronary artery calcification (CAC) is directly correlated with quantity of coronary atherosclerotic plaque. In the current study, we tested for genetic variants influencing extent of CAC via interaction with smoking (GxS), by conducting a GxS discovery GWAS in Genetic Epidemiology Network of Arteriopathy (GENOA) sibships (N = 915 European Americans) followed by replication in Framingham Heart Study (FHS) sibships (N = 1025 European Americans). Generalized estimating equations accounted for the correlation within sibships in strata-specific groups of smokers and nonsmokers, as well as GxS interaction. Primary analysis found SNPs that showed suggestive associations (p≤10⁻⁵) in GENOA GWAS, but these index SNPs did not replicate in FHS. However, secondary analysis was able to replicate candidate gene regions in FHS using other SNPs (+/−250 kb of GENOA index SNP). In smoker and nonsmoker groups, replicated genes included TCF7L2 (p = 6.0×10⁻⁵) and WWOX (p = 4.5×10⁻⁶); and TNFRSF8 (p = 7.8×10⁻⁵), respectively. For GxS interactions, replicated genes included TBC1D4 (p = 6.9×10⁻⁵) and ADAMTS9 (P = 7.1×10⁻⁵). Interestingly, these genes are involved in inflammatory pathways mediated by the NF-κB axis. Since smoking is known to induce chronic and systemic inflammation, association of these genes likely reflects roles in CAC development via inflammatory pathways. Furthermore, the NF-κB axis regulates bone remodeling, a key physiological process in CAC development. In conclusion, GxS GWAS has yielded evidence for novel loci that are associated with CAC via interaction with smoking, providing promising new targets for future population-based and functional studies of CAC development.

Construction of gene clusters resembling genetic causal mechanisms for common complex disease with an application to young-onset hypertension

BACKGROUND

Lack of power and reproducibility are caveats of genetic association studies of common complex diseases. Indeed, the heterogeneity of disease etiology demands that causal models consider the simultaneous involvement of multiple genes. Rothman's sufficient-cause model, which is well known in epidemiology, provides a framework for such a concept. In the present work, we developed a three-stage algorithm to construct gene clusters resembling Rothman's causal model for a complex disease, starting from finding influential gene pairs followed by grouping homogeneous pairs.

RESULTS

The algorithm was trained and tested on 2,772 hypertensives and 6,515 normotensives extracted from four large Caucasian and Taiwanese databases. The constructed clusters, each featured by a major gene interacting with many other genes and identified a distinct group of patients, reproduced in both ethnic populations and across three genotyping platforms. We present the 14 largest gene clusters which were capable of identifying 19.3% of hypertensives in all the datasets and 41.8% if one dataset was excluded for lack of phenotype information. Although a few normotensives were also identified by the gene clusters, they usually carried less risky combinatory genotypes (insufficient causes) than the hypertensive counterparts. After establishing a cut-off percentage for risky combinatory genotypes in each gene cluster, the 14 gene clusters achieved a classification accuracy of 82.8% for all datasets and 98.9% if the information-short dataset was excluded. Furthermore, not only 10 of the 14 major genes but also many other contributing genes in the clusters are associated with either hypertension or hypertension-related diseases or functions.

CONCLUSIONS

We have shown with the constructed gene clusters that a multi-causal pie-multi-component approach can indeed improve the reproducibility of genetic markers for complex disease. In addition, our novel findings including a major gene in each cluster and sufficient risky genotypes in a cluster for disease onset (which coincides with Rothman's sufficient cause theory) may not only provide a new research direction for complex diseases but also help to reveal the disease etiology.

Coronary heart disease is associated with a mutation in mitochondrial tRNA

Coronary heart disease (CHD) is the leading cause of death worldwide. Mitochondrial genetic determinant for the development of CHD remains poorly explored. We report there the clinical, genetic, molecular and biochemical characterization of a four-generation Chinese family with maternally inherited CHD. Thirteen of 32 adult members in this family exhibited variable severity and age-at-onset of CHD. Mutational analysis of their mitochondrial genomes identified the tRNA(Thr) 15927G>A mutation belonging to the Eastern Asian haplogroup B5. The anticipated destabilization of a highly conserved base-pairing (28C-42G) by the 15927G>A mutation affects structure and function of tRNA(Thr). Northern analysis revealed ≈80% decrease in the steady-state level of tRNA(Thr) in the mutant cell lines carrying the 15927G>A mutation. The 15927G>A mutation changed the conformation of tRNA(Thr), as suggested by slower electrophoretic mobility of mutated tRNA with respect to the wild-type molecule. In addition, ∼39% reduction in aminoacylated efficiency of tRNA(Thr) was observed in mutant cells derived from this Chinese family. An in vivo mitochondrial protein labeling analysis showed ∼53% reduction in the rate of mitochondrial translation in mutant cells. The impaired mitochondrial protein synthesis leads to defects in overall respiratory capacity or malate/glutamate-promoted respiration or succinate/glycerol-3-phosphate-promoted respiration, or N,N,N',N'-tetramethyl-pphenylenediamine/ascorbate-promoted respiration in mutant cells. An increasing production of reactive oxygen species was observed in the mutant cells carrying the 15927G>A mutation. These results provide the direct evidence that the tRNA(Thr) 15927G>A mutation is associated with CHD. Our findings may provide new insights into pathophysiology and intervention targets of this disorder.

Addressing the Challenges of Detecting Epistasis in Genome-Wide Association Studies of Common Human Diseases Using Biological Expert Knowledge

Recent technological developments in the field of genetics have given rise to an abundance of research tools, such as genome-wide genotyping, that allow researchers to conduct genome-wide association studies (GWAS) for detecting genetic variants that confer increased or decreased susceptibility to disease. However, discovering epistatic, or gene-gene, interactions in high dimensional datasets is a problem due to the computational complexity that results from the analysis of all possible combinations of single-nucleotide polymorphisms (SNPs). A recently explored approach to this problem employs biological expert knowledge, such as pathway or protein-protein interaction information, to guide an analysis by the selection or weighting of SNPs based on this knowledge. Narrowing the evaluation to gene combinations that have been shown to interact experimentally provides a biologically concise reason why those two genes may be detected together statistically. This chapter discusses the challenges of discovering epistatic interactions in GWAS and how biological expert knowledge can be used to facilitate genome-wide genetic studies.

ACE I/D and eNOS E298D gene polymorphisms in Saudi subjects with hypertension

BACKGROUND

Hypertension has a multifactorial background based on genetic and environmental interactive factors.

OBJECTIVES

We aimed to test for the association of the angiotensin-converting enzyme (ACE) and endothelial nitric oxide synthase (eNOS) gene polymorphisms with hypertension.

SUBJECTS AND METHODS

Participants included 120 Saudi patients with hypertension and 250 normal healthy controls. For all participants, DNA was processed for characterization of ACE I/D and eNOS E298D gene polymorphisms.

RESULTS

Hypertensive cases showed a significantly higher frequency of the ACE mutant D allele carriage (98.3% vs. 92.4%, p = 0.028, OR = 4.8). Cases with hypertension associated with diabetes and obesity showed 100% mutant D allele carriage. Regarding the eNOS E298D polymorphism, the frequency of the mutant D allele carriage was only observed to be higher among cases with hypertension associated with diabetes and obesity, in comparison with controls, yet not reaching statistical significance (41.2% vs. 34%, p > 0.05).

CONCLUSIONS

There is increased frequency of ACE and eNOS mutant allele carriage among Saudi patients affected with hypertension, particularly if accompanied by obesity and diabetes.