Genomewide Association Studies in Cardiovascular Disease—An Update 2011

Endothelial dysfunction and cardiovascular diseases: The role of human induced pluripotent stem cells and tissue engineering

Cardiovascular disease (CVD) remains to be the leading cause of death globally today and therefore the need for the development of novel therapies has become increasingly important in the cardiovascular field. The mechanism(s) behind the pathophysiology of CVD have been laboriously investigated in both stem cell and bioengineering laboratories. Scientific breakthroughs have paved the way to better mimic cell types of interest in recent years, with the ability to generate any cell type from reprogrammed human pluripotent stem cells. Mimicking the native extracellular matrix using both organic and inorganic biomaterials has allowed full organs to be recapitulated in vitro. In this paper, we will review techniques from both stem cell biology and bioengineering which have been fruitfully combined and have fueled advances in the cardiovascular disease field. We will provide a brief introduction to CVD, reviewing some of the recent studies as related to the role of endothelial cells and endothelial cell dysfunction. Recent advances and the techniques widely used in both bioengineering and stem cell biology will be discussed, providing a broad overview of the collaboration between these two fields and their overall impact on tissue engineering in the cardiovascular devices and implications for treatment of cardiovascular disease.

MRAS in coronary artery disease-Unchartered territory

Genome-wide association studies (GWAS) have identified coronary artery disease (CAD) susceptibility locus on chromosome 3q22.3. This locus contains a cluster of several genes that includes muscle rat sarcoma virus (MRAS). Common MRAS variants are also associated with CAD causing risk factors such as hypertension, dyslipidemia, obesity, and type II diabetes. The MRAS gene is an oncogene that encodes a membrane-bound small GTPase. It is involved in a variety of signaling pathways, regulating cell differentiation and cell survival (mitogen-activated protein kinase [MAPK]/extracellular signal-regulated kinase and phosphatidylinositol 3-kinase) as well as acute phase response signaling (tumor necrosis factor [TNF] and interleukin 6 [IL6] signaling). In this review, we will summarize the role of genetic MRAS variants in the etiology of CAD and its comorbidities with the focus on tissue distribution of MRAS isoforms, cell type/tissue specificity, and mode of action of single nucleotide variants in MRAS associated complex traits. Finally, we postulate that CAD risk variants in the MRAS locus are specific to smooth muscle cells and lead to higher levels of MRAS, particularly in arterial and cardiac tissue, resulting in MAPK-dependent tissue hypertrophy or hyperplasia.

Identification of potential biological processes and key genes in diabetes-related stroke through weighted gene co-expression network analysis

BACKGROUND

Type 2 diabetes mellitus (T2DM) is an established risk factor for acute ischemic stroke (AIS). Although there are reports on the correlation of diabetes and stroke, data on its pathogenesis is limited. This study aimed to explore the underlying biological mechanisms and promising intervention targets of diabetes-related stroke.

METHODS

Diabetes-related datasets (GSE38642 and GSE44035) and stroke-related datasets (GSE16561 and GSE22255) were obtained from the Gene Expression omnibus (GEO) database. The key modules for stroke and diabetes were identified by weight gene co-expression network analysis (WGCNA). Gene Ontology (GO) and Kyoto Encyclopedia of Genes Genomes (KEGG) analyses were employed in the key module. Genes in stroke- and diabetes-related key modules were intersected to obtain common genes for T2DM-related stroke. In order to discover the key genes in T2DM-related stroke, the Cytoscape and protein-protein interaction (PPI) network were constructed. The key genes were functionally annotated in the Reactome database.

RESULTS

By intersecting the diabetes- and stroke-related crucial modules, 24 common genes for T2DM-related stroke were identified. Metascape showed that neutrophil extracellular trap formation was primarily enriched. The hub gene was granulin precursor (GRN), which had the highest connectivity among the common genes. In addition, functional enrichment analysis indicated that GRN was involved in neutrophil degranulation, thus regulating neutrophil extracellular trap formation.

CONCLUSIONS

This study firstly revealed that neutrophil extracellular trap formation may represent the common biological processes of diabetes and stroke, and GRN may be potential intervention targets for T2DM-related stroke.

Targeting the ASMase/S1P pathway protects from sortilin-evoked vascular damage in hypertension

Sortilin has been positively correlated with vascular disorders in humans. No study has yet evaluated the possible direct effect of sortilin on vascular function. We used pharmacological and genetic approaches coupled with study of murine and human samples to unravel the mechanisms recruited by sortilin in the vascular system. Sortilin induced endothelial dysfunction of mesenteric arteries through NADPH oxidase 2 (NOX2) isoform activation, dysfunction that was prevented by knockdown of acid sphingomyelinase (ASMase) or sphingosine kinase 1. In vivo, recombinant sortilin administration induced arterial hypertension in WT mice. In contrast, genetic deletion of sphingosine-1-phosphate receptor 3 (S1P3) and gp91phox/NOX2 resulted in preservation of endothelial function and blood pressure homeostasis after 14 days of systemic sortilin administration. Translating these research findings into the clinical setting, we detected elevated sortilin levels in hypertensive patients with endothelial dysfunction. Furthermore, in a population-based cohort of 270 subjects, we showed increased plasma ASMase activity and increased plasma levels of sortilin, S1P, and soluble NOX2-derived peptide (sNOX2-dp) in hypertensive subjects, and the increase was more pronounced in hypertensive subjects with uncontrolled blood pressure. Our studies reveal what we believe is a previously unrecognized role of sortilin in the impairment of vascular function and in blood pressure homeostasis and suggest the potential of sortilin and its mediators as biomarkers for the prediction of vascular dysfunction and high blood pressure.

Associations of CD14 variants with the triglyceride levels and risk of myocardial infarction in an Eastern Chinese Han population

BACKGROUND

CD14 is crucial in the progression of myocardial infarction (MI). Several studies have explored the association between the risk of MI and the CD14 C-260 T polymorphism, but have reported inconsistent results.

METHODS

This study analyzed the association of the CD14 C-260 T polymorphism with susceptibility to MI. Totally, 240 MI patients and 298 normal subjects were included. The association between MI risk and the target polymorphism was assessed using 95% confidence intervals and odds ratios obtained through logistic regression.

RESULTS

The T allele of the CD14 C-260 T polymorphism was linked with an elevated risk of MI in Chinese Han people; subgroup analysis indicated that this effect was associated with smoking, male gender, and hypertension. In addition, the data revealed that different genotype carriers of the CD14 C-260 T polymorphism showed significantly distinct TG levels in MI patients.

CONCLUSION

Totally, the T allele of the CD14 C-260 T polymorphism is associated with an elevated risk of MI.

Screening of Multiple Biomarkers Associated With Ischemic Stroke in Atrial Fibrillation

Background To explore the pathophysiological features of ischemic stroke in patients with atrial fibrillation (AF), we evaluated the association between 268 plasma proteins and subsequent ischemic stroke in 2 large AF cohorts receiving oral anticoagulation. Methods and Results A case-cohort sample of patients with AF from the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial, including 282 cases with ischemic stroke or systemic embolism and a random sample of 4124 without these events, during 1.9 years of follow-up was used for identification. Validation was provided by a similar case-cohort sample of patients with AF from the RE-LY (Randomized Evaluation of Long-Term Anticoagulation Therapy) trial, including 149 cases with ischemic stroke/systemic embolism and a random sample of 1062 without these events. In plasma obtained before randomization, 268 unique biomarkers were measured with OLINK proximity extension assay panels (CVD II, CVD III, and Inflammation) and conventional immunoassays. The association between biomarkers and outcomes was evaluated by random survival forest and adjusted Cox regression. According to random survival forest or Cox regression analyses, the biomarkers most strongly and consistently associated with ischemic stroke/systemic embolism were matrix metalloproteinase-9, NT-proBNP (N-terminal pro-B-type natriuretic peptide), osteopontin, sortilin, soluble suppression of tumorigenesis 2, and trefoil factor-3. The corresponding hazard ratios (95% CIs) for an interquartile difference were as follows: 1.18 (1.00-1.38), 1.55 (1.28-1.88), 1.28 (1.07-1.53), 1.19 (1.02-1.39), 1.23 (1.05-1.45), and 1.19 (0.97-1.45), respectively. Conclusions In patients with AF, of 268 unique biomarkers, the 6 biomarkers most strongly associated with subsequent ischemic stroke/systemic embolism represent fibrosis/remodeling (matrix metalloproteinase-9 and soluble suppression of tumorigenesis 2), cardiac dysfunction (NT-proBNP), vascular calcification (osteopontin), metabolism (sortilin), and mucosal integrity/ischemia (trefoil factor-3). Registration URL: https://www.clinicaltrials.gov. Unique Identifiers: NCT00412984 and NCT00262600.

Non-O-blood types associated with higher risk of high-grade atrioventricular block

Introduction

The non-O phenotype of the ABO genotype has been linked with an increased risk of cardiovascular disease. Atrioventricular (AV) block (AVB) is defined as retardation or cessation in the route of an electrical impulse passing from the atria to the ventricles because of an anatomical or functional disruption in the conduction system. We aimed to interpret the association between blood group status and high-grade atrioventricular block (HAVB).

Material and methods

This study was implemented as a retrospective review of the recorded data of patients diagnosed with high-grade AV block and a control group. The study population consisted of 640 patients with HAVB and 570 control subjects.

Results

Presence of non-O blood group (p < 0.001) was significantly more prevalent in HAVB patients than in the control subjects. Blood group type was the sole independent predictor of HAVB in multiple regression analysis (p < 0.001, OR = 1.35, 95% CI: 1.08–1.57). Also, third-degree AVB had a higher incidence in the non-O blood subgroup and also non-O blood group was a predictor of third-degree AVB (p < 0.001, OR = 1.39, 95% CI: 1.13–1.69). The incidence of HAVB did not distinguish between the two Rh (D) groups. Rh (D) status did not have an impact on HAVB.

Conclusions

This is the first study that has evaluated the potential relationship between HAVB and ABO blood groups. The main finding of this report is that patients with non-O blood group types have a higher risk for development of HAVB compared with O blood group patients.

Novel biomarkers for cardiovascular risk

Cardiovascular disease refers to different diseases involving the heart and/or the arteries and/or the veins. Cardiovascular disease, overall considered, is a notable source of morbidity and mortality worldwide. Therefore, several research studies are dedicated to explore, by means of biomarkers, the possiblity to calculate the cardiovascular risk both for the onset and for the complications of the related clinical manifestations such as coronary artery disease, carotid artery stenosis, peripheral artery disease, arterial aneurysm, chronic venous disease and venous thromboembolism. This review discusses the most updated information in the area of the novel biomarkers related to omics, imaging techniques and clinical data, that may help physicians in order to improve the knowledge and the management of the cardiovascular risk.

A genetic variant near adaptor-related protein complex 2 alpha 2 subunit gene is associated with coronary artery disease in a Chinese population

Background

Adaptor-related protein complex 2 alpha 2 subunit (AP2A2) gene encodes a protein-a subunit of the AP-2 adaptor protein complex. Evidence has revealed that benzodiazepine receptor-associated protein 1 (BZRAP1) is abundant in the hippocampus with potential effects on brain diseases. Recently, an epidemiological study reported that two variants (rs7396366 and rs2526378) closest to the AP2A2 and BZRAP1 genes are associated with higher plasma lipids and Alzheimer’s disease. Whether the two single nucleotide polymorphisms (SNPs) are actually relevant to coronary artery disease (CAD) and CAD severity remains elusive. Our aim was to assess whether these two SNPs are relevant to CAD and its severity in a Chinese population.

Methods

Three hundred and thirty-five patients with documented CAD (282 stable CAD, 28 non-ST-segment elevation myocardial infarction, 25 ST-segment elevation myocardial infarction), and 372 non-CAD controls were included in the study. The participants were divided into two groups according to coronary angiography results. CAD patients were further demarcated into subgroups with one-, two-, or three-vessel stenosis. Genotypes at rs7396366 and rs2526378 were examined using polymerase chain reaction-ligase detection reaction. The association between these two SNPs with CAD and its severity were analyzed.

Results

The frequency of the rs7396366 TT genotype was significantly higher in CAD patients than in controls (13.7% vs. 7.8%, 95% CI: 1.15–3.07, P = 0.014). Subjects with a variant genotype T allele had an increased risk of CAD compared with G allele carriers (additive model: 95% CI: 1.21–3.35, P = 0.008). After adjustment for traditional cardiovascular risk factors, analysis of the dominant models involving rs7396366 also showed that T allele carriers had a significantly higher risk for CAD than G allele carriers had (dominant model: OR 1.48, 95% CI: 1.03–2.14, P = 0.035). Age, sex, type 2 diabetes mellitus, fasting plasma glucose, and the TT genotype in rs7396366 were significantly associated with three-vessel lesions. Despite these significant outcomes of rs7396366, information on rs2526378 showed no significant difference between CAD patients and non-CAD controls.

Conclusion

Our results show that the T allele and TT genotype in rs7396366, closest to the AP2A2 gene, are linked to an increased risk of CAD and its severity in a Chinese population.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0905-2) contains supplementary material, which is available to authorized users.

Interaction between a variant of chromosome 9p21.3 locus and diet antioxidant capacity on metabolic syndrome in Tehrani adults

BACKGROUND

Genome-wide association studies have shown that risk alleles on chromosome 9p21.3 locus, are associated with increasing the risk of cardiovascular diseases (CVDs). Several epidemiological studies have found that metabolic syndrome (MetS) is associated with CVDs. Dietary antioxidants also have shown to have potential favorable effects on MetS prevention. This study examined the interactions between rs1333048 genotypes on 9p21 genetic region and Total antioxidant capacity (TAC) on odds of MetS.

METHODS

263 Tehrani adults were enrolled in this cross-sectional study. The MetS was defined according to the ATPIII. Dietary intake was assessed daily using a FFQ with 147 items. Dietary TAC was assessed according to United States Department of Agriculture database for oxygen radical absorbance capacity (ORAC). Bioelectrical impedance analysis method was used for body analysis and rs1333048 were genotyped by restriction fragment length polymorphism method. Participants were categorized into three groups based on rs1333048 genotypes.

RESULTS

The results demonstrate that, prevalence of C allele was 52.85% and A allele was 47.15%. After adjustment for confunder variable, this study demonstrated an interaction between AA genotype and high Lyophilic oxygen radical absorbance capacity (L-ORAC) and high Hydrophilic oxygen radical absorbance capacity (H-ORAC) intake on low odds of MetS (OR = 0.24, 95% CI = 0.06-0.94, P for interaction = 0.04, OR = 0.26, 95% CI = 0.06-0.99, P for interaction = 0.04). Also, our result indicated, there was no interaction between AA genotype and high total oxygen radical absorbance capacity (T-ORAC) and total phenolic intakes on reduce odds of MetS (OR = 0.07, 95% CI = 0.07-1.10, P for interaction = 0.07, OR = 0.58, 95% CI = 0.16-2.07, P for interaction = 0.40) respectively.

CONCLUSION

The results of the present study indicate that high L-ORAC and high H-ORAC intake may modify the elevated odds of MetS in AA genotype of rs1333048 on the 9p21 genetic locus.

High expression of long chain acyl-coenzyme A synthetase 1 in peripheral blood may be a molecular marker for assessing the risk of acute myocardial infarction

The current study aimed to investigate whether the increased expression of long chain acyl-coenzymeA synthetase 1 (ACSL1) in peripheral blood leukocytes (PBL) may be a molecular marker for the genetic evaluation of acute myocardial infarction (AMI). The mechanism of action of ACSL1 in the pathogenesis of AMI was also investigated. A total of 75 patients with AMI and 70 individuals without coronary heart disease were selected to participate in the present study. The demographic and clinical information of the enrolled subjects was recorded. Reverse transcription quantitative polymerase chain reaction and western blot analysis were applied to measure the expression of ACSL1 at the mRNA and protein levels. It was demonstrated that the expression of ACSL1 mRNA and protein in PBL was increased in patients with AMI compared with controls. Logistic regression analysis indicated that ACSL1 expression in PBL was an independent risk factor of AMI. There was a significant positive association between the level of ACSL1 expression and the degree of atherosclerosis in the coronary artery. Furthermore, patients with AMI exhibited an increased risk of atherosclerosis due to increased fasting blood glucose, total cholesterol, triglyceride and lipoprotein levels and decreased high-density lipoprotein levels, compared with controls. Therefore, the current study demonstrated that ACSL1 expression was increased in the PBLs of patients with AMI. The elevated expression of ACSL1 acts an independent risk factor of AMI and may act as a potential biomarker when determining the risk of AMI.

Association of genetic variants of hemostatic genes with myocardial infarction in Egyptian patients

Hemostatic genes polymorphisms are well known to be associated with venous thrombosis, but their association with arterial thrombosis especially myocardial infarction (MI) remains to be clarified. We investigated the role of three hemostatic gene polymorphisms, prothrombin G20210A, factor XIII (FXIII) Val34Leu (G/T), and fibrinogen-β-455G/A and their coexistence in Egyptian patients with MI. The possible correlation of these polymorphisms with plasma fibrinogen level was also evaluated. The study included 120 patients with MI and 60 healthy volunteers. Gene polymorphisms were tested using multiplex polymerase chain reaction and reverse-hybridization technique. Plasma fibrinogen level was determined by ELISA. Our study showed an increased risk of MI with fibrinogen β-455G/A heterozygosity as well as FXIII Val34Leu homo and heterozygosity. In addition, the FXIII T allele (Leu34) and fibrinogen β-455A allele were significantly associated with MI. Conversely, the prevalence of prothrombin mutation did not differ between patients with MI and controls. Combined carriers of FXIII Leu34 and fibrinogen-β455A alleles were at higher risk of MI, whereas combined FXIII Val34Leu and prothrombin 20210A polymorphisms did not show increased risk for MI compared with controls. Plasma fibrinogen levels were significantly higher in patients with MI than controls. In MI patients, plasma fibrinogen levels were significantly higher in those with FXIII GT/TT or fibrinogen β-455 GA, while were significantly lower in those with prothrombin 20210 GA compared with patients with wild type genotypes. In conclusion, our results suggest a possible thrombotic predisposition of FXIII Val34Leu, fibrinogen β-455G/A polymorphisms and their coexistence for MI. These polymorphisms may add complexity to disease pathology by increasing plasma fibrinogen level. Extended studies are needed to confirm our results; nevertheless, these data may be implicated in genetic counseling and screening of high-risk individuals.

Distribution of ABO Blood Groups and Coronary Artery Calcium

BACKGROUND

ABO blood groups have been confirmed to be associated with cardiovascular diseases such as coronary artery disease. However, whether ABO blood group is correlated with coronary artery calcium (CAC) is still unknown.

METHOD

301 patients with coronary artery calcium score (CACS) assessed by computed tomography were consecutively enrolled and divided into two groups: with calcium group (CACS>0, n=104) and without calcium group (CACS=0, n=197). Distribution of ABO blood groups was evaluated between the two groups.

RESULTS

The percentage of A blood type was significantly higher (p=0.008) and O blood type was significantly lower (p=0.037) in the calcium group. Univariate regression analysis showed that age, total cholesterol, low density lipoprotein cholesterol, high-sensitivity C-reactive protein, A blood type were positively correlated with CAC, and O blood type was inversely associated with CAC. Multivariate regression analysis showed that A blood type was independently associated with CAC (odds ratio: 2.217, 95% confidence interval: 1.260-3.900, p=0.006) even after further adjustment for variables that were clearly different between the two groups.

CONCLUSIONS

Our data has suggested for the first time that A blood type was an independent risk marker for CAC.

Rare Variants in NOD1 Associated with Carotid Bifurcation Intima-Media Thickness in Dominican Republic Families

Cardiovascular disorders including ischemic stroke (IS) and myocardial infarction (MI) are heritable; however, few replicated loci have been identified. One strategy to identify loci influencing these complex disorders is to study subclinical phenotypes, such as carotid bifurcation intima-media thickness (bIMT). We have previously shown bIMT to be heritable and found evidence for linkage and association with common variants on chromosome 7p for bIMT. In this study, we aimed to characterize contributions of rare variants (RVs) in 7p to bIMT. To achieve this aim, we sequenced the 1 LOD unit down region on 7p in nine extended families from the Dominican Republic (DR) with strong evidence for linkage to bIMT. We then performed the family-based sequence kernel association test (famSKAT) on genes within the 7p region. Analyses were restricted to single nucleotide variants (SNVs) with population based minor allele frequency (MAF) <5%. We first analyzed all exonic RVs and then the subset of only non-synonymous RVs. There were 68 genes in our analyses. Nucleotide-binding oligomerization domain (NOD1) was the most significantly associated gene when analyzing exonic RVs (famSKAT p = 9.2x10^-4; number of SNVs = 14). We achieved suggestive replication of NOD1 in an independent sample of twelve extended families from the DR (p = 0.055). Our study provides suggestive statistical evidence for a role of rare variants in NOD1 in bIMT. Studies in mice have shown Nod1 to play a role in heart function and atherosclerosis, providing biologic plausibility for a role in bIMT thus making NOD1 an excellent bIMT candidate.

Roles of SIRT3 in heart failure: from bench to bedside

Heart failure (HF) represents the most common endpoint of most cardiovascular diseases (CVDs) which are the leading causes of death around the world. Despite the advances in treating CVDs, the prevalence of HF continues to increase. It is believed that better results of prognosis are obtained from prevention rather than additional treatment for HF. Therefore, it is reasonable to prevent the development of CVDs or other complications to HF. Most types of HF are attributed to contractile dysfunction, cardiac hypertrophy or remodeling, and ischemic injuries. SIRT3 is a mitochondrial nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase whose substrates vary from metabolic biogenesis-associated proteins to stress-responsive proteins. In recent years, a number of studies have highlighted the cardio-protective role of SIRT3 and, as such, efforts have been made to induce over-expression or increased activity of this protein. In this review, we provide an overview of the roles of SIRT3 in cardiac hypertrophy induced by pressure overload or agonists and cardiomyocytes ischemic injuries. Moreover, we will introduce the application of SIRT3 agonists in the prevention of cardiac hypertrophy and ischemia reperfusion injury.

Does a medical history of hypertension influence disclosing genetic testing results of the risk for salt-sensitive hypertension, in primary care?

Objective

Disclosing genetic testing results may contribute to the prevention and management of many common diseases. However, whether the presence of a disease influences these effects is unclear. This study aimed to clarify the difference in the effects of disclosing genetic testing results of the risk for developing salt-sensitive hypertension on the behavioral modifications with respect to salt intake in hypertensive and nonhypertensive patients.

Methods

A cross-sectional study using a self-administered questionnaire was conducted for outpatients aged >20 years (N=2,237) at six primary care clinics and hospitals in Japan. The main factors assessed were medical histories of hypertension, salt preferences, reduced salt intakes, and behavior modifications for reducing salt intake. Behavioral modifications of participants were assessed using their behavior stages before and after disclosure of the hypothetical genetic testing results.

Results

Of the 2,237 participants, 1,644 (73.5%) responded to the survey. Of these respondents, 558 (33.9%) patients were hypertensive and 1,086 (66.1%) were nonhypertensive. After being notified of the result “If with genetic risk”, the nonhypertensive participants were more likely to make positive behavioral modifications compared to the hypertensive patients among all participants and in those aged <65 years (adjusted relative ratio [ad-RR], 1.76; 95% confidence interval, 1.12−2.76 and ad-RR, 1.99; 1.11−3.57, respectively). In contrast, no difference in negative behavioral modifications between hypertensive and nonhypertensive patients was detected after being notified of the result “If without genetic risk” (ad-RR, 1.05; 95% confidence interval, 0.70−1.57).

Conclusion

The behavior of modifying salt intake after disclosure of the genetic testing results differed between hypertensive and nonhypertensive patients. Disclosing a genetic risk for salt-sensitive hypertension was likely to cause nonhypertensive patients, especially those aged <65 years, to improve their behavior regarding salt intake. We conclude that disclosing genetic testing results could help prevent hypertension, and that the doctor should communicate the genetic testing results to those patients with a medical history of hypertension, or those who are at risk of developing hypertension.

Differential protein expression and basal lamina remodeling in human heart failure

PURPOSE

A goal of this study was to identify and investigate previously unrecognized components of the remodeling process in the progression to heart failure by comparing protein expression in ischemic failing (F) and nonfailing (NF) human hearts.

EXPERIMENTAL DESIGN

Protein expression differences were investigated using multidimensional protein identification and validated by Western analysis. This approach detected basal lamina (BL) remodeling, and further studies analyzed samples for evidence of structural BL remodeling. A rat model of pressure overload (PO) was studied to determine whether nonischemic stressors also produce BL remodeling and impact cellular adhesion.

RESULTS

Differential protein expression of collagen IV, laminin α2, and nidogen-1 indicated BL remodeling develops in F versus NF hearts Periodic disruption of cardiac myocyte BL accompanied this process in F, but not NF heart. The rat PO myocardium also developed BL remodeling and compromised myocyte adhesion compared to sham controls.

CONCLUSIONS AND CLINICAL RELEVANCE

Differential protein expression and evidence of structural and functional BL alterations develop during heart failure. The compromised adhesion associated with this remodeling indicates a high potential for dysfunctional cellular integrity and tethering in failing myocytes. Therapeutically targeting BL remodeling could slow or prevent the progression of heart disease.

ADAMTS7 locus confers high cross-race risk for development of coronary atheromatous plaque

Genome-wide association studies of coronary artery disease (CAD) have recently identified a new susceptibility locus, ADAMTS7, in subjects of European ancestry. However, the significance of this locus in Chinese populations has not been identified. Therefore, this study was designed to evaluate the effect of rs3825807, a non-synonymous variant in the prodomain of the ADAMTS7 protease, on CAD risk and atherosclerosis severity in a Chinese population. We performed genetic association analyses in two independent case-control cohorts, which included a total of 8154 participants. Additionally, the association between the ADAMTS7 rs3825807 genotype and the proportion of CAD patients with 3- and 1-vessel disease was tested. We found that ADAMTS7 rs3825807 was associated with susceptibility to CAD in a Chinese population [odds ratio (OR) = 1.15, 95 % confidence interval (CI) = 1.05-1.26, P = 0.002]. The association remained significant after adjusting for clinical covariates (adjusted OR = 1.12, 95 % CI = 1.02-1.24, P = 0.02). Among 3741 angiographically documented CAD patients, the rs3825807 risk allele showed a significant association with disease severity (P = 0.04, trend P = 0.02). Additionally, 3-vessel disease demonstrated a strong and direct association with ADAMTS7 rs3825807 gene dosage (P = 0.02). Overall, our findings indicate that the significant associations observed between this coding variant in ADAMTS7 and the risk of CAD development are cross-ethnic, and the gene dosage is consistent with the degree of coronary atheromatous burden.

Genetic insight into the role of MRAS in coronary artery disease risk

The muscle Ras (MRAS) gene polymorphisms have been reported to be associated with coronary artery disease (CAD) in white Europeans. The aim of this study was to ascertain the role of MRAS gene polymorphisms in conferring susceptibility to CAD, and to explore the effect on severity of CAD in Chinese population. We genotyped 5009 Chinese individuals (2466 CAD cases and 2543 controls) for eight single nucleotide polymorphisms (SNPs) around MRAS and used logistic regression analysis to determine whether they were associated with CAD. The association of the SNP loci on the severity of CAD was analyzed using a logistic and linear regression analysis, respectively. Our results revealed that an intron SNP, rs1199337, tends to be marginally associated with CAD as previously reported in Caucasians (nominal P=0.01, OR 1.10, 95% CI 1.01-1.20). However, this association did not retain statistically significant levels after applying Bonferroni's correction for multiple testing (corrected P=0.08). There was no significant association between other loci and CAD (nominal P>0.05). We did not observe any significant association between the SNPs and severity of CAD (all P values>0.05). From the above results, the MRAS gene loci might have a minor effect in conferring susceptibility to CAD in Chinese population.

Association of Hemostatic Gene Polymorphisms With Early-Onset Ischemic Heart Disease in Egyptian Patients

The association between hereditary thrombophilia and venous thrombosis is well established but controversial data exist with respect to arterial thrombosis. We performed a pilot study on 31 patients with acute myocardial infarction (AMI), 21 patients with unstable angina (UA), and 20 healthy volunteers to investigate the role of various hemostatic gene polymorphisms in young Egyptian patients, who survived their first ischemic heart disease (IHD). Thrombophilic gene polymorphisms were tested using multiplex polymerase chain reaction and reverse-hybridization technique. We showed an increased risk of AMI with factor V (FV) Leiden and prothrombin G20210A heterozygosity. The increased risks of UA was associated with GA and A allele of fibrinogen β-455G→A polymorphism. Conversely, factor XIII (FXIII) Val34Leu GT and T allele were protective in the UA group. Nevertheless, the prevalence of FV H1299R, plasminogen activator inhibitor 1 4G/5G, glycoprotein IIIa C1565T, 5,10-methylenetetrahydrofolate reductase C677T, and A1298C mutations did not differ between patients with IHD and controls. The data have clinical implications regarding screening and thromboprophylaxis in high-risk individuals younger than 40 years.

Biobanks for cardiovascular epidemiology and prevention

Biobanks for medical research are organized collections of biological samples associated with personal data and information on their donors, to be stored for an indefinite period of time. The storage of biological samples has varied considerably over time, ranging from the informal storage of tissue specimens in a researcher's freezer in the past, to the present well-structured formal repositories. Large-scale population-related biobanks are being set up in several countries and will allow not only research into individual diseases, but also approaches to a wide range of health-related issues, such as physical activity, eating, drinking, education and pollution, among others. The purpose of this article is to discuss how biobanks have improved research in cardiovascular disease epidemiology and prevention, by describing the most relevant population-based epidemiological studies that used set-up biobanks and stored samples for research. The selection of epidemiological studies and biobanks was based on their dimensions and their contribution to the field.

Sortilin: the mechanistic link between genes, cholesterol, and coronary artery disease

Hyperlipidemia is an important risk factor for cardiovascular disease globally, but there is still much mystery surrounding the topic of lipid regulation. Many studies have attempted to assess the underlying genetic basis of low-density lipoprotein (LDL) metabolism. Recently, multiple genome-wide association studies identified genes that strongly associate with plasma lipid concentration and cardiovascular disease. Compelling evidence linking the SORT1 gene to both LDL cholesterol (LDL-C) levels and the risk of coronary artery disease emerged from the data, prompting the search for the molecules and mechanisms responsible for this association. Three recent studies explored this relation through sortilin, the gene product of SORT1, and an intracellular trafficking molecule. Careful, hypothesis-driven experimental designs elucidated the potential mechanisms of sortilin's role in LDL-C metabolism. However, each study's conclusions differed in the details of SORT1's association to LDL-C and the subcellular mechanisms at work. Nevertheless, these 3 studies demonstrate how a complex disease such as hyperlipidemia can be evaluated from the scope of the genome down through the level of cellular regulation. Their findings serve as a platform for further study of LDL-C metabolism and hyperlipidemia while also providing lessons on how to better study other complex diseases.

The Wuhan-Zhuhai (WHZH) cohort study of environmental air particulate matter and the pathogenesis of cardiopulmonary diseases: study design, methods and baseline characteristics of the cohort

BACKGROUND

Particulate air pollution has been recognized to be associated with a wide range of adverse health effects, including increased mortality, morbidity, exacerbation of respiratory conditions. However, earlier physiological or pathological changes or long-term bodies' reaction to air pollutants have not been studied in depth in China. The Wuhan-Zhuhai (WHZH) cohort study is designed to investigate the association between air pollutants exposure and physiological or pathological reactions on respiratory and cardiovascular system.

METHODS/DESIGN

The cohort is a community-based prospective study that includes 4812 individuals aged 18-80 years. The collections of data were conducted from April to May 2011 in Wuhan city and in May 2012 in Zhuhai city. At baseline, data on demographic and socioeconomic information, occupational history, family disease history, lifestyle, cooking mode, daily travel mode, physical activity and living condition have been collected by questionnaires. Participants underwent an extensive physical examination, including anthropometry, spirometry, electrocardiography, and measurements of blood pressure, heart rate, exhaled nitric oxide and carbon monoxide. Potential conditions in the lung, heart, liver, spleen, and skin were synchronously performed. In addition, samples of morning urine, fasting blood serum and plasma were collected during physical health examination. DNA were extracted and were stored at -80°C. Environment concentrations of particulate matter and chemicals were determined for 15 days in each of four seasons. Participants are followed for physiological or pathological changes or incidence of cardiopulmonary diseases every 3 years.

DISCUSSION

The results obtained in WHZH cohort study may increase a better understanding of the relationship between particulate air pollution and its components and possible health damages. And the potential mechanisms underlying the development of cardiopulmonary diseases has implications for the development of prevention and treatment strategies.

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.

CDKN2B expression and subcutaneous adipose tissue expandability: possible influence of the 9p21 atherosclerosis locus

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The tumor suppressor gene CDKN2B is highly expressed in human adipose tissue.

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Risk alleles at the 9p21 locus modify CDKN2B expression in a BMI-dependent fashion.

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There is an inverse relationship between expression of CDKN2B and adipogenic genes.

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CDKN2B expression influences to postprandial triacylglycerol clearance.

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CDKN2B expression in adipose tissue is linked to markers of hepatic steatosis.

Risk alleles within a gene desert at the 9p21 locus constitute the most prevalent genetic determinant of cardiovascular disease. Previous research has demonstrated that 9p21 risk variants influence gene expression in vascular tissues, yet the biological mechanisms by which this would mediate atherosclerosis merits further investigation. To investigate possible influences of this locus on other tissues, we explored expression patterns of 9p21-regulated genes in a panel of multiple human tissues and found that the tumor suppressor CDKN2B was highly expressed in subcutaneous adipose tissue (SAT). CDKN2B expression was regulated by obesity status, and this effect was stronger in carriers of 9p21 risk alleles. Covariation between expression of CDKN2B and genes implemented in adipogenesis was consistent with an inhibitory effect of CDKN2B on SAT proliferation. Moreover, studies of postprandial triacylglycerol clearance indicated that CDKN2B is involved in down-regulation of SAT fatty acid trafficking. CDKN2B expression in SAT correlated with indicators of ectopic fat accumulation, including markers of hepatic steatosis. Among genes regulated by 9p21 risk variants, CDKN2B appears to play a significant role in the regulation of SAT expandability, which is a strong determinant of lipotoxicity and therefore might contribute to the development of atherosclerosis.

Cholesterol, lipoproteins, high-sensitivity c-reactive protein, and other risk factors for atherosclerosis

Coronary heart disease is a common and costly epidemic in the Western world. Intensive study has led to a deeper understanding of the pathogenesis of coronary disease and risk stratification. Traditional risk factor assessment has focused on parameters derived from the Framingham Heart Study (age, hypertension, cholesterol, family history, and cigarette smoking). New emerging risk factors, both biological and genetic, are reshaping the understanding of heart disease and the approach to risk stratification. As these emerging assays become more standardized, automated, and inexpensive to perform, they are becoming increasingly important tools in the assessment and treatment of coronary heart disease.

Plurigon: three dimensional visualization and classification of high-dimensionality data

High-dimensionality data is rapidly becoming the norm for biomedical sciences and many other analytical disciplines. Not only is the collection and processing time for such data becoming problematic, but it has become increasingly difficult to form a comprehensive appreciation of high-dimensionality data. Though data analysis methods for coping with multivariate data are well-documented in technical fields such as computer science, little effort is currently being expended to condense data vectors that exist beyond the realm of physical space into an easily interpretable and aesthetic form. To address this important need, we have developed Plurigon, a data visualization and classification tool for the integration of high-dimensionality visualization algorithms with a user-friendly, interactive graphical interface. Unlike existing data visualization methods, which are focused on an ensemble of data points, Plurigon places a strong emphasis upon the visualization of a single data point and its determining characteristics. Multivariate data vectors are represented in the form of a deformed sphere with a distinct topology of hills, valleys, plateaus, peaks, and crevices. The gestalt structure of the resultant Plurigon object generates an easily-appreciable model. User interaction with the Plurigon is extensive; zoom, rotation, axial and vector display, feature extraction, and anaglyph stereoscopy are currently supported. With Plurigon and its ability to analyze high-complexity data, we hope to see a unification of biomedical and computational sciences as well as practical applications in a wide array of scientific disciplines. Increased accessibility to the analysis of high-dimensionality data may increase the number of new discoveries and breakthroughs, ranging from drug screening to disease diagnosis to medical literature mining.

Heart failure and chronic obstructive pulmonary disease: the challenges facing physicians and health services

Pulmonary disease is common in patients with heart failure, through shared risk factors and pathophysiological mechanisms. Adverse pulmonary vascular remodelling and chronic systemic inflammation characterize both diseases. Concurrent chronic obstructive pulmonary disease presents diagnostic and therapeutic challenges, and is associated with increased morbidity and mortality. The cornerstones of therapy are beta-blockers and beta-agonists, whose pharmacological properties are diametrically opposed. Each disease is implicated in exacerbations of the other condition, greatly increasing hospitalizations and associated health care costs. Such multimorbidity is a key challenge for health-care systems oriented towards the treatment of individual diseases. Early identification and treatment of cardiopulmonary disease may alleviate this burden. However, diagnostic and therapeutic strategies require further validation in patients with both conditions.

Genetic epidemiology of cardiometabolic risk factors and their clustering patterns in Mexican American children and adolescents: the SAFARI Study

Pediatric metabolic syndrome (MS) and its cardiometabolic components (MSCs) have become increasingly prevalent, yet little is known about the genetics underlying MS risk in children. We examined the prevalence and genetics of MS-related traits among 670 non-diabetic Mexican American (MA) children and adolescents, aged 6-17 years (49 % female), who were participants in the San Antonio Family Assessment of Metabolic Risk Indicators in Youth study. These children are offspring or biological relatives of adult participants from three well-established Mexican American family studies in San Antonio, TX, at increased risk of type 2 diabetes. MS was defined as ≥3 abnormalities among 6 MSC measures: waist circumference, systolic and/or diastolic blood pressure, fasting insulin, triglycerides, HDL-cholesterol, and fasting and/or 2-h OGTT glucose. Genetic analyses of MS, number of MSCs (MSC-N), MS factors, and bivariate MS traits were performed. Overweight/obesity (53 %), pre-diabetes (13 %), acanthosis nigricans (33 %), and MS (19 %) were strikingly prevalent, as were MS components, including abdominal adiposity (32 %) and low HDL-cholesterol (32 %). Factor analysis of MS traits yielded three constructs: adipo-insulin-lipid, blood pressure, and glucose factors, and their factor scores were highly heritable. MS itself exhibited 68 % heritability. MSC-N showed strong positive genetic correlations with obesity, insulin resistance, inflammation, and acanthosis nigricans, and negative genetic correlation with physical fitness. MS trait pairs exhibited strong genetic and/or environmental correlations. These findings highlight the complex genetic architecture of MS/MSCs in MA children, and underscore the need for early screening and intervention to prevent chronic sequelae in this vulnerable pediatric population.

Gene expression signatures of coronary heart disease

OBJECTIVE

To identify transcriptomic biomarkers of coronary heart disease (CHD) in 188 cases with CHD and 188 age- and sex-matched controls who were participants in the Framingham Heart Study.

APPROACH AND RESULTS

A total of 35 genes were differentially expressed in cases with CHD versus controls at false discovery rate<0.5, including GZMB, TMEM56, and GUK1. Cluster analysis revealed 3 gene clusters associated with CHD, 2 linked to increased erythrocyte production and a third to reduced natural killer and T cell activity in cases with CHD. Exon-level results corroborated and extended the gene-level results. Alternative splicing analysis suggested that GUK1 and 38 other genes were differentially spliced in cases with CHD versus controls. Gene Ontology analysis linked ubiquitination and T-cell-related pathways with CHD.

CONCLUSIONS

Two bioinformatically defined groups of genes show consistent associations with CHD. Our findings are consistent with the hypotheses that hematopoesis is upregulated in CHD, possibly reflecting a compensatory mechanism, and that innate immune activity is disrupted in CHD or altered by its treatment. Transcriptomic signatures may be useful in identifying pathways associated with CHD and point toward novel therapeutic targets for its treatment and prevention.

Non-homologous end-joining pathway associated with occurrence of myocardial infarction: gene set analysis of genome-wide association study data

PURPOSE

DNA repair deficiencies have been postulated to play a role in the development and progression of cardiovascular disease (CVD). The hypothesis is that DNA damage accumulating with age may induce cell death, which promotes formation of unstable plaques. Defects in DNA repair mechanisms may therefore increase the risk of CVD events. We examined whether the joints effect of common genetic variants in 5 DNA repair pathways may influence the risk of CVD events.

METHODS

The PLINK set-based test was used to examine the association to myocardial infarction (MI) of the DNA repair pathway in GWAS data of 866 subjects of the GENetic DEterminants of Restenosis (GENDER) study and 5,244 subjects of the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) study. We included the main DNA repair pathways (base excision repair, nucleotide excision repair, mismatch repair, homologous recombination and non-homologous end-joining (NHEJ)) in the analysis.

RESULTS

The NHEJ pathway was associated with the occurrence of MI in both GENDER (P = 0.0083) and PROSPER (P = 0.014). This association was mainly driven by genetic variation in the MRE11A gene (PGENDER = 0.0001 and PPROSPER = 0.002). The homologous recombination pathway was associated with MI in GENDER only (P = 0.011), for the other pathways no associations were observed.

CONCLUSION

This is the first study analyzing the joint effect of common genetic variation in DNA repair pathways and the risk of CVD events, demonstrating an association between the NHEJ pathway and MI in 2 different cohorts.

Heart failure

Despite major improvements in the treatment of virtually all cardiac disorders, heart failure (HF) is an exception, in that its prevalence is rising, and only small prolongations in survival are occurring. An increasing fraction, especially older women with diabetes, obesity, and atrial fibrillation exhibit HF with preserved systolic function. Several pathogenetic mechanisms appear to be operative in HF. These include increased hemodynamic overload, ischemia-related dysfunction, ventricular remodeling, excessive neurohumoral stimulation, abnormal myocyte calcium cycling, excessive or inadequate proliferation of the extracellular matrix, accelerated apoptosis, and genetic mutations. Biomarkers released as a consequence of myocardial stretch, imbalance between formation and breakdown of extracellular matrix, inflammation, and renal failure are useful in the identification of the pathogenetic mechanism and, when used in combination, may become helpful in estimating prognosis and selecting appropriate therapy. Promising new therapies that are now undergoing intensive investigation include an angiotensin receptor neprilysin inhibitor, a naturally-occurring vasodilator peptide, a myofilament sensitizer and several drugs that enhance Ca++ uptake by the sarcoplasmic reticulum. Cell therapy, using autologous bone marrow and cardiac progenitor cells, appears to be promising, as does gene therapy. Chronic left ventricular assistance with continuous flow pumps is being applied more frequently and successfully as destination therapy, as a bridge to transplantation, and even as a bridge to recovery and explantation. While many of these therapies will improve the care of patients with HF, significant reductions in prevalence will require vigorous, multifaceted, preventive approaches.

Metabolomics and ischaemic heart disease

Ischaemic heart disease accounts for nearly half of the global cardiovascular disease burden. Aetiologies relating to heart disease are complex, but dyslipidaemia, oxidative stress and inflammation are cardinal features. Despite preventative measures and advancements in treatment regimens with lipid-lowering agents, the high prevalence of heart disease and the residual risk of recurrent events continue to be a significant burden to the health sector and to the affected individuals and their families. The development of improved risk models for the early detection and prevention of cardiovascular events in addition to new therapeutic strategies to address this residual risk are required if we are to continue to make inroads into this most prevalent of diseases. Metabolomics and lipidomics are modern disciplines that characterize the metabolite and lipid complement respectively, of a given system. Their application to ischaemic heart disease has demonstrated utilities in population profiling, identification of multivariate biomarkers and in monitoring of therapeutic response, as well as in basic mechanistic studies. Although advances in magnetic resonance and mass spectrometry technologies have given rise to the fields of metabolomics and lipidomics, the plethora of data generated presents challenges requiring specific statistical and bioinformatics applications, together with appropriate study designs. Nonetheless, the predictive and re-classification capacity of individuals with various degrees of risk by the plasma lipidome has recently been demonstrated. In the present review, we summarize evidence derived exclusively by metabolomic and lipidomic studies in the context of ischaemic heart disease. We consider the potential role of plasma lipid profiling in assessing heart disease risk and therapeutic responses, and explore the potential mechanisms. Finally, we highlight where metabolomic studies together with complementary -omic disciplines may make further inroads into the understanding, detection and treatment of ischaemic heart disease.

Association analysis of polymorphisms in ROCK2 with cardiovascular disease in a Chinese population

Background

Rho-kinase (ROCK) has been shown to play an important role in cardiovascular disease such as coronary artery disease (CAD) and hypertension. Recently, common variants of ROCK2 have been reported to influence blood pressure, but the relationship between common ROCK2 variants and cardiovascular disease has not been extensively studied in the Chinese population.

Methods

To derive a more precise estimation of their relationship, we screened for the common variants by direct sequencing of all exons of ROCK2, and then we performed genetic association analyses in a CAD case–control study, including a total of 1344 cases and 1267 ethnically and geographically matched controls.

Results

Unconditional logistic regression showed that no significant association between common variants in the coding region of ROCK2 and CAD was observed in our study (for rs978906, OR = 0.92, 95% CI 0.72–1.20 and P = 0.63; for rs2230774, OR = 0.90, 95% CI 0.70–1.16 and P = 0.47; for rs56304104, OR = 0.97, 95% CI 0.70–1.31 and P = 0.83; respectively).

Conclusions

The relationship between the ROCK2 polymorphisms and cardiovascular disease risk cannot be entirely discounted and warrants further evaluation in a large population.

ABO Blood Groups and Cardiovascular Diseases

ABO blood groups have been associated with various disease phenotypes, particularly cardiovascular diseases. Cardiovascular diseases are the most common causes of death in developed countries and their prevalence rate is rapidly growing in developing countries. There have been substantial historical associations between non-O blood group status and an increase in some cardiovascular disorders. Recent GWASs have identified ABO as a locus for thrombosis, myocardial infarction, and multiple cardiovascular risk biomarkers, refocusing attention on mechanisms and potential for clinical advances. As we highlight in this paper, more recent work is beginning to probe the molecular basis of the disease associations observed in these observational studies. Advances in our understanding of the physiologic importance of various endothelial and platelet-derived circulating glycoproteins are elucidating the mechanisms through which the ABO blood group may determine overall cardiovascular disease risk. The role of blood group antigens in the pathogenesis of various cardiovascular disorders remains a fascinating subject with potential to lead to novel therapeutics and prognostics and to reduce the global burden of cardiovascular diseases.

Impact of Next-Generation Sequencing (NGS) technology on cardiovascular disease research

In recent years, hundreds of gene loci associated with multiple cardiovascular pathologies and traits have been identified through high-throughput Next-Generation Sequencing (NGS) technology. Due to the increasing efficiency and decreasing cost of NGS, rapid progresses anticipated in the field of CVD research. This review summarizes the main strategies of CV research with NGS at the level of genomics, transcriptomics, epigenetics, and proteomics.