Strategies beyond genome-wide association studies for atherosclerosis

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.

Analysis of 61 SNPs from the CAD specific genomic loci reveals unique set of SNPs as significant markers in the Southern Indian population of Hyderabad

Background

The present study is a part of the major project on coronary artery disease (CAD) carried out at Indian Statistical Institute, Hyderabad to investigate the pattern of association of SNPs selected from the CAD specific genomic loci. The study is expected to portray the genetic susceptibility profile of CAD specifically in the Southern Indian population of Hyderabad.

Methods

The study was conducted in a cohort of 830 subjects comprising 350 CAD cases and 480 controls from Hyderabad. A prioritized set of 61 SNPs selected from the NHGRI GWAS catalogue were genotyped using FluidigmNanofluidic SNP Genotyping System and appropriate statistical analyses were used in interpreting the results.

Results

After data pruning, out of 45 SNPs qualified for the association analysis, four SNPs were found to be highly significantly associated with increased risk for CAD even after Bonferroni correction for multiple testing (p < 0.001). These results were also replicated in the random subsets of the pooled cohort (70, 50 and 30%) suggesting internal consistency. The ROC analysis of the risk scores of the significant SNPs suggested highly significant area under curve (AUC = 0.749; p < 0.0001) implying predictive utility of these risk variants.

Conclusions

The rs10455872 of LP(A) gene in particular showed profound risk for CAD (OR 35.9; CI 16.7–77.2) in this regional Indian population. The other significant SNP associations observed with respect to the pooled CAD cohort and in different anatomical and phenotypic severity categories reflected on the role of genetic heterogeneity in the clinical heterogeneity of CAD. The SNP rs7582720 of WDR12 gene, albeit not individually associated with CAD, was found to be conferring significant risk through epistatic interaction with two SNPs (rs6589566, rs1263163 in ZPR1, APOA5-APOA4 genes) of the 11q23.3 region.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02562-4.

Examining the Association between Mitochondrial Genome Variation and Coronary Artery Disease

Large-scale genome-wide association studies have identified hundreds of single-nucleotide variants (SNVs) significantly associated with coronary artery disease (CAD). However, collectively, these explain <20% of the heritability. Hypothesis: Here, we hypothesize that mitochondrial (MT)-SNVs might present one potential source of this “missing heritability”. Methods: We analyzed 265 MT-SNVs in ~500,000 UK Biobank individuals, exploring two different CAD definitions: a more stringent (myocardial infarction and/or revascularization; HARD = 20,405), and a more inclusive (angina and chronic ischemic heart disease; SOFT = 34,782). Results: In HARD cases, the most significant (p < 0.05) associations were for m.295C>T (control region) and m.12612A>G (ND5), found more frequently in cases (OR = 1.05), potentially related to reduced cardiorespiratory fitness in response to exercise, as well as for m.12372G>A (ND5) and m.11467A>G (ND4), present more frequently in controls (OR = 0.97), previously associated with lower ROS production rate. In SOFT cases, four MT-SNVs survived multiple testing corrections (at FDR < 5%), all potentially conferring increased CAD risk. Of those, m.11251A>G (ND4) and m.15452C>A (CYB) have previously shown significant associations with body height. In line with this, we observed that CAD cases were slightly less physically active, and their average body height was ~2.00 cm lower compared to controls; both traits are known to be related to increased CAD risk. Gene-based tests identified CO2 associated with HARD/SOFT CAD, whereas ND3 and CYB associated with SOFT cases (p < 0.05), dysfunction of which has been related to MT oxidative stress, obesity/T2D (CO2), BMI (ND3), and angina/exercise intolerance (CYB). Finally, we observed that macro-haplogroup I was significantly (p < 0.05) more frequent in HARD cases vs. controls (3.35% vs. 3.08%), potentially associated with response to exercise. Conclusions: We found only spurious associations between MT genome variation and HARD/SOFT CAD and conclude that more MT-SNV data in even larger study cohorts may be needed to conclusively determine the role of MT DNA in CAD.

Impact of genetic polymorphisms on platelet function and response to anti platelet drugs

Cardiovascular genomic consists in the identification of polymorphic genes responsible for the susceptibility to cardiovascular disease including coronary artery disease (CAD). Genes involved in platelet activation and aggregation play a key role in the predisposition to CAD. A considerable inter-variability of platelet response to agonists and to drugs exists and in particular the hyper-reactivity phenotype seems to be heritable. Besides glycoproteins and receptors expressed on platelets surface whose mutations significantly impact on platelet function, moreover researchers in the last decades have paid great attention to the genes involved in the response to anti-platelet drugs, considering their pivotal role in the treatment and outcomes of CAD patients especially those undergoing PCI. With the outbreak of advanced techniques developed to analyse human genetic footprints, researchers nowadays have shifted from genetic linkage analysis and a candidate gene approach toward genome-wide association (GWAS) studies and the analysis of miRNA-mRNA expression profiles.

Protease-activated receptor 1 inhibits cholesterol efflux and promotes atherogenesis via cullin 3-mediated degradation of the ABCA1 transporter

Although signaling of thrombin via its receptor protease-activated receptor 1 (Par1) is known to occur in atherothrombosis, its link to the actual pathogenesis of this condition is less clear. To better understand the role of thrombin-Par1 signaling in atherosclerosis, here we have studied their effects on cellular cholesterol efflux in mice. We found that by activating Par1 and cullin 3-mediated ubiquitination and degradation of ABC subfamily A member 1 (ABCA1), thrombin inhibits cholesterol efflux in both murine macrophages and smooth muscle cells. Moreover, disruption of the Par1 gene rescued ABCA1 from Western diet-induced ubiquitination and degradation and restored cholesterol efflux in apolipoprotein E-deficient (ApoE^-/-) mice. Similarly, the Par1 deletion diminished diet-induced atherosclerotic lesions in the ApoE^-/- mice. These observations for the first time indicate a role for thrombin-Par1 signaling in the pathogenesis of diet-induced atherosclerosis. We identify cullin 3 as a cullin-RING ubiquitin E3 ligase that mediates ABCA1 ubiquitination and degradation and thereby inhibits cholesterol efflux. Furthermore, compared with peripheral blood mononuclear cells (PBMCs) from ApoE^-/- mice, the PBMCs from ApoE^-/-:Par1^-/- mice exhibited decreased trafficking to inflamed arteries of Western diet-fed ApoE^-/- mice. This finding suggested that besides inhibiting cholesterol efflux, thrombin-Par1 signaling also plays a role in the recruitment of leukocytes during diet-induced atherogenesis. Based on these findings, we conclude that thrombin-Par1 signaling appears to contribute to the pathogenesis of atherosclerosis by impairing cholesterol efflux from cells and by recruiting leukocytes to arteries.

Association between chemokine CXC ligand 12 gene polymorphism (rs1746048) and coronary heart disease: A MOOSE-compliant meta-analysis

Recently a large number of investigations have implicated the association between the chemokine CXC ligand 12 gene polymorphism (rs1746048) and risk of coronary heart disease (CHD), but the results remain debatable. The aim of our study was to provide more compelling evidence for the relationship between rs1746048 and CHD risk. Studies eligible for this meta-analysis were identified through electronic search of PubMed, EMBASE, and CNKI. Two authors performed independent literature review and study quality assessment by using the Newcastle-Ottawa Scale checklist. The odds ratios (ORs) with 95% confidence intervals (CIs) were pooled in a specific genetic model to assess the association. The meta-analysis of 48,852 patients and 64,386 controls from 12 studies showed that patients with rs1746048 had 1.11 times of high risk in developing CHD (OR = 1.11; 95% CI = 1.09-1.14; P < .005; I = 35.8%). The increased risk of CHD was also found in both Asian (OR = 1.07; 95%CI = 1.02-1.12; P < .005; I = 40.6%) and Caucasian populations (OR = 1.14; 95% CI = 1.10-1.18; P < .005; I = 22.2%). The results of our meta-analysis suggested that chemokine CXC ligand 12 gene polymorphism (rs1746048) may be linked with susceptibility to CHD.

Genomics era and complex disorders: Implications of GWAS with special reference to coronary artery disease, type 2 diabetes mellitus, and cancers

The Human Genome Project (HGP) has identified millions of single nucleotide polymorphisms (SNPs) and their association with several diseases, apart from successfully characterizing the Mendelian/monogenic diseases. However, the dissection of precise etiology of complex genetic disorders still poses a challenge for human geneticists. This review outlines the landmark results of genome-wide association studies (GWAS) with respect to major complex diseases - Coronary artery disease (CAD), type 2 diabetes mellitus (T2DM), and predominant cancers. A brief account on the current Indian scenario is also given. All the relevant publications till mid-2015 were accessed through web databases such as PubMed and Google. Several databases providing genetic information related to these diseases were tabulated and in particular, the list of the most significant SNPs identified through GWAS was made, which may be useful for designing studies in functional validation. Post-GWAS implications and emerging concepts such as epigenomics and pharmacogenomics were also discussed.

Increased Intimal Hyperplasia After Vascular Injury in Male Androgen Receptor-Deficient Mice

Intimal hyperplasia is a vascular pathological process involved in the pathogenesis of atherosclerosis. Data suggest that T, the most important sex steroid hormone in males, protects men from atherosclerotic cardiovascular disease. T mainly acts via the androgen receptor (AR), and in this study we evaluated formation of intimal hyperplasia in male AR knockout (ARKO) mice using a vascular injury model. Two weeks after ligation of the carotid artery, male ARKO mice showed increased intimal area and intimal thickness compared with controls. After endothelial denudation by an in vivo scraping injury, there was no difference in the reendothelialization in ARKO compared with control mice. Ex vivo, we observed increased outgrowth of vascular smooth muscle cells from ARKO compared with control aortic tissue explants; the number of outgrown cells was almost doubled in ARKO. In vitro, stimulation of human aortic vascular smooth muscle cells with a physiological T concentration inhibited both migration and proliferation of the cells. Analyzing the expression of central regulators of cell proliferation and migration, we found that mRNA and protein levels of p27 were lower in uninjured arteries from ARKO mice and that T replacement to castrated male mice increased p27 mRNA in an AR-dependent manner. In conclusion, AR deficiency in male mice increases intimal hyperplasia in response to vascular injury, potentially related to the effects of androgens/AR to inhibit proliferation and migration of smooth muscle cells.

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.

Relationship between CYP17A1 genetic polymorphism and coronary artery disease in a Chinese Han population

BACKGROUND

CYP17A1 gene encodes P450c17 proteins, which is a key enzyme that catalyzes the formation of sex hormones. Many clinical studies showed that sex hormones levels play an important role in the pathogenesis of coronary artery disease (CAD). However, the relationship between CYP17A1 genetic polymorphisms and CAD remains unclear. The aim of this study was to investigate the association of CYP17A1 genetic polymorphisms with CAD in a Han population of China.

METHODS

A total of 997 people include 490 patients and 507 controls were selected for the present study. Five single-nucleotide polymorphisms (SNPs) (rs4919686, rs1004467, rs4919687, rs10786712, and rs2486758) were genotyped by using the real-time PCR (TaqMan) method.

RESULTS

For men, the rs10786712 was found to be associated with CAD in a recessive model (P=0.016), after adjustment of the major confounding factors, the significant difference was retained (OR=1.644, 95% confidence interval [CI]: 1.087-2.488, P=0.019). For women, the rs1004467 was also found to be associated with CAD in a dominant model (P=0.038), the difference remained statistically significant after multivariate adjustment (OR=1.623, 95% CI: 1.023-2.576, P=0.040). The distribution of rs4919687 genotypes showed a significant difference between CAD and control participants in a recessive model (P=0.019), the significant difference was retained after adjustment for covariates (OR=0.417, 95% CI: 0.188-0.926, P=0.032).

CONCLUSION

Rs1004467, rs4919687, rs10786712 of CYP17A1 gene are associated with CAD in Han population of China. The TT genotype of rs10786712 could be a protective genetic marker of CAD in men. The CC genotype of rs1004467 and the AA genotype of rs4919687 could be risk genetic markers of CAD in women. However, large sample size study including other SNPs of CYP17A1 should be performed in future studies.

[Genetic analyses as basis for a personalized medicine in patients with coronary artery disease]

Knowledge about the etiology of coronary artery disease (CAD) entered new dimensions using genome-wide association studies. The current situation is that 46 chromosomal loci have been identified to be associated with CAD with genome-wide significance, i.e. p<5×10(-8), in Western Europeans. As the individual DNA sequence remains unchanged after fertilization, the risk variants cannot occur due to confounders, such as secondary disease processes. Thus, it can be proposed that these variants are directly affecting a primary and thereby causal pathophysiological process in CAD. Interestingly, only 20% of the effects mediated by the identified loci can be explained by the influence of traditional risk factors. This implies that yet unknown mechanisms and, as a consequence, new therapeutic targets play an important role in the pathophysiology of CAD. However, the high allele frequency of risk loci was also surprising. In the diploid chromosome set Western European individuals carry on average 30-50 risk variants at the 46 loci. Considering this, every individual in the population carries a larger or smaller genetic predisposition for CAD. On the other hand it is remarkable that many risk allele carriers seem to be able to compensate the genetic risk: even in old age not everyone suffers from CAD. This indicates yet unknown gene-gene and gene-environment interactions and limits the current possibilities in individual risk prediction.

Apolipoprotein C3 genetic polymorphisms are associated with lipids and coronary artery disease in a Chinese population

BACKGROUND

The disorder of triglyceride (TG) metabolism leading to hypertriglyceridemia is an independent risk factor for coronary artery disease (CAD). Variants in the apolipoprotein C3 (APOC3) gene were found to be associated with elevated TG levels. The purpose of this study was to investigate the effect of two polymorphisms (1100 C/T and 3238 C/G) of APOC3 on plasma lipid and risk of CAD in a Chinese population.

METHODS

The study population consisted of 600 patients with CAD and 600 age- and gender-matched controls. The APOC3 gene polymorphism was analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Patients with CAD had a significantly higher frequency of APOC3 3238 GG genotype [odds ratio (OR) =1.64, 95% confidence interval (CI) =1.10, 2.43; P = 0.01] and APOC3 3238 G allele (OR =1.27, 95% CI =1.04, 1.55; P = 0.02) than controls. The findings are still emphatic by the Bonferroni correction. When stratifying by hyperlipidemia, CAD patients with hyperlipidemia had a significantly higher frequency of APOC3 3238 GG genotype (OR =1.73, 95% CI =1.13, 2.64; P = 0.01) than without hyperlipidemia. The APOC3 3238 G allele was significantly associated with increasing plasma TG levels and very-low-density lipoprotein cholesterol (VLDL-C) levels both in cases and controls (P < 0.001).

CONCLUSIONS

The APOC3 3238 G allele might contribute to an increased risk of CAD as a result of its effect on TG and VLDL-C metabolism.

An integrated genomic-transcriptomic approach supports a role for the proto-oncogene BCL3 in atherosclerosis

Data with border-line statistical significance, copiously generated in genome-wide association studies of coronary artery disease (CAD), could include functionally relevant associations. We propose an integrated genomic and transcriptomic approach for unravelling new potential genetic signatures of atherosclerosis. Fifteen among 91 single nucleotide polymorphisms (SNPs) were first selected for association in a sex- and age-adjusted model by examining 510 patients with CAD and myocardial infarction and 388 subjects with normal coronary arteries (CAD-free) in the replication stages of a genome-wide association study. We investigated the expression of 71 genes proximal to the 15 tag-SNPs by two subsequent steps of microarray-based mRNA profiling, the former in vascular smooth muscle cell populations, isolated from non-atherosclerotic and atherosclerotic human carotid portions, and the latter in whole carotid specimens. BCL3 and PVRL2, contiguously located on chromosome 19, and ABCA1, extensively investigated before, were found to be differentially expressed. BCL3 and PVRL2 SNPs were genotyped within a second population of CAD patients (n=442) and compared with CAD-free subjects (n=393). The carriership of the BCL3 rs2965169 G allele was more represented among CAD patients and remained independently associated with CAD after adjustment for all the traditional cardiovascular risk factors (odds ratio=1.70 with 95% confidence interval 1.07-2.71), while the BCL3 rs8100239 A allele correlated with metabolic abnormalities. The up-regulation of BCL3 mRNA levels in atherosclerotic tissue samples was consistent with BCL3 protein expression, which was detected by immunostaining in the intima-media of atherosclerotic specimens, but not within non-atherosclerotic ones. Our integrated approach suggests a role for BCL3 in cardiovascular diseases.

The CXCL12/CXCR4 chemokine ligand/receptor axis in cardiovascular disease

The chemokine receptor CXCR4 and its ligand CXCL12 play an important homeostatic function by mediating the homing of progenitor cells in the bone marrow and regulating their mobilization into peripheral tissues upon injury or stress. Although the CXCL12/CXCR4 interaction has long been regarded as a monogamous relation, the identification of the pro-inflammatory chemokine macrophage migration inhibitory factor (MIF) as an important second ligand for CXCR4, and of CXCR7 as an alternative receptor for CXCL12, has undermined this interpretation and has considerably complicated the understanding of CXCL12/CXCR4 signaling and associated biological functions. This review aims to provide insight into the current concept of the CXCL12/CXCR4 axis in myocardial infarction (MI) and its underlying pathologies such as atherosclerosis and injury-induced vascular restenosis. It will discuss main findings from in vitro studies, animal experiments and large-scale genome-wide association studies. The importance of the CXCL12/CXCR4 axis in progenitor cell homing and mobilization will be addressed, as will be the function of CXCR4 in different cell types involved in atherosclerosis. Finally, a potential translation of current knowledge on CXCR4 into future therapeutical application will be discussed.

ADAMTS-7 expression increases in the early stage of angiotensin II-induced renal injury in elderly mice

BACKGROUND/AIMS

We investigated the recently described family of proteinases, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTs), and matrix metalloproteinases (MMPs) as inflammatory mediators in inflammatory kidney damage by studying ADAMTS-1, -4, and -7 and MMP-9 expression in elderly mouse kidneys after angiotensin II (Ang II) administration.

METHODS

Ang II (2.5 µg/kg/min) or norepinephrine (8.3 µg/kg/min) was subcutaneously infused in old mice. Renal injury was assessed by hematoxylin-eosin staining, 24-h albuminuria, and immunohistochemistry to evaluate inflammatory cell markers. The mRNA and protein expression of ADAMTS-1, -4, and -7 and MMP-9 were determined using real-time PCR, Western blot, and immunohistochemistry 3 days after Ang II or norepinephrine administration.

RESULTS

Elderly mice in the Ang II group developed hypertension and pathological kidney damage. The mRNA and protein levels of ADAMTS-7 in the Ang II group were 3.3 ± 1.1 (P = 0.019) and 1.6 ± 0.1 (P = 0.047) vs. 1.0 ± 0.1 and 1.0 ± 0.1 in the control group on day 3. In contrast, treatment with the hypertensive agent norepinephrine did not lead to obvious renal damage or an increase in renal ADAMTS-7 expression.

CONCLUSIONS

Renal ADAMTS-7 expression was induced by Ang II in elderly mice. The overexpression of ADATMTS-7 might contribute to early inflammatory kidney damage associated with aging.

Pathogenesis of coronary artery disease: focus on genetic risk factors and identification of genetic variants

Coronary artery disease (CAD) is the leading cause of death and disability worldwide, and its prevalence is expected to increase in the coming years. CAD events are caused by the interplay of genetic and environmental factors, the effects of which are mainly mediated through cardiovascular risk factors. The techniques used to study the genetic basis of these diseases have evolved from linkage studies to candidate gene studies and genome-wide association studies. Linkage studies have been able to identify genetic variants associated with monogenic diseases, whereas genome-wide association studies have been more successful in determining genetic variants associated with complex diseases. Currently, genome-wide association studies have identified approximately 40 loci that explain 6% of the heritability of CAD. The application of this knowledge to clinical practice is challenging, but can be achieved using various strategies, such as genetic variants to identify new therapeutic targets, personal genetic information to improve disease risk prediction, and pharmacogenomics. The main aim of this narrative review is to provide a general overview of our current understanding of the genetics of coronary artery disease and its potential clinical utility.

Association of the RYR3 gene polymorphisms with atherosclerosis in elderly Japanese population

BACKGROUND

The Ryanodine receptor 3 gene (RYR3) encodes an intracellular calcium channel that mediates the efflux of Ca2+ from intracellular stores. Two single-nucleotide polymorphisms (SNPs) in the RYR3 gene have been shown to associate with stroke (rs877087) and carotid intima-media thickness (rs2229116) in two independent genome-wide association studies (GWAS) in Caucasian. We investigated the effect of these two SNPs as well as the 31.1 kilobases spanning region on atherosclerosis in Japanese population.

METHODS

Atherosclerotic severity was assessed by carotid artery (n = 1374) and pathological atherosclerosis index (PAI) (n = 1262), which is a macroscopic examination of the luminal surfaces of 8 systemic arteries in consecutive autopsy samples. 4 tag SNPs in the 31.1 Kb region, rs877087, rs2132207, rs658750 and rs2229116, were genotyped and haplotypes were inferred to study the association with atherosclerotic indices.

RESULTS

rs877087 and rs2229116 were associated with PAI (OR = 2.07 [1.04-4.12] (95% CI), p = 0.038; and OR = 1.38 [1.02-1.86], p = 0.035, respectively). rs2229116 was also associated with common carotid atherosclerosis (OR = 1.45 [1.13-1.86], p = 0.003). The risk allele of rs2229116 was opposite from the original report. The haplotype block of this 31.1 Kb region was different between Caucasian and Japanese. Haplotype analysis revealed that only TAGG haplotype was associated with PAI (OR = 0.67 [0.48-0.94], p = 0.020) and atherosclerosis of common carotid artery (OR = 0.75 [0.58-0.98], p = 0.034).

CONCLUSION

rs877087 and rs2229116 of RYR3 gene are associated with atherosclerosis severity in Japanese. The functional difference caused by rs2229116 needs to be investigated.

Introduction to personalized medicine in diabetes mellitus

The world is facing an epidemic rise in diabetes mellitus (DM) incidence, which is challenging health funders, health systems, clinicians, and patients to understand and respond to a flood of research and knowledge. Evidence-based guidelines provide uniform management recommendations for "average" patients that rarely take into account individual variation in susceptibility to DM, to its complications, and responses to pharmacological and lifestyle interventions. Personalized medicine combines bioinformatics with genomic, proteomic, metabolomic, pharmacogenomic ("omics") and other new technologies to explore pathophysiology and to characterize more precisely an individual's risk for disease, as well as response to interventions. In this review we will introduce readers to personalized medicine as applied to DM, in particular the use of clinical, genetic, metabolic, and other markers of risk for DM and its chronic microvascular and macrovascular complications, as well as insights into variations in response to and tolerance of commonly used medications, dietary changes, and exercise. These advances in "omic" information and techniques also provide clues to potential pathophysiological mechanisms underlying DM and its complications.

Positive association between GCKR rs780093 polymorphism and coronary heart disease in the aged Han Chinese

OBJECTIVE

Previous studies have confirmed that GCKR rs780093 polymorphism is associated with triglyceride (TG), a known risk factor of coronary heart disease (CHD). The goal of our study is to explore the association of GCKR rs780093 polymorphism with CHD in Han Chinese population.

METHODS AND RESULTS

A total of 568 CHD cases and 494 non-CHD controls were enrolled in the current case-control study. Genotyping was done using melting temperature shift (Tm-shift) approach. Our results also showed that GCKR rs780093 polymorphism was significantly associated with TG level (P = 0.0016). Although there was no significant association between cases and controls (P > 0.05), a breakdown analysis by age yielded a significant association of GCKR rs780093 polymorphism with CHD in individuals aged 65 and older (genotype: χ(2) = 6.86; df = 2; P = 0.03; allele: χ(2) = 4.11; df = 1; P = 0.04).

CONCLUSION

Our findings confirmed the contribution of GCKR rs780093 polymorphism to TG metabolism and demonstrated GCKR rs780093 as a risk factor of CHD in individuals aged 65 and older.

Nutrigenetics and nutrigenomics of atherosclerosis

The latest genome-wide association studies (GWAS) have re-energized our effort to understand the genetic basis of atherosclerotic cardiovascular disease. Although the knowledge generated by GWAS has confirmed that mediators of inflammation and perturbed lipid metabolism are major players in cardiovascular disease (CVD) development, much of individual disease heritability remains unexplained by the variants identified through GWAS. Moreover, results from interventions that aim at the pharmaceutical modification of lipid parameters fall short of expectation. These elusive treatment goals based on heritability studies highlight a key supportive, and perhaps even primary, role of nutritional therapy to achieve better health outcomes. Nonetheless, effective and specific interventions for CVD prevention using principles of "personalized" nutrition require a better knowledge of gene-diet interactions, an area that remains poorly explored. Dietary fatty acids such as omega-3 polyunsaturated fatty acids (PUFAs) are an excellent example of a widely studied "environment" that interacts with the genetic makeup in relation to CVD. A thorough exploration of the nutrigenomics and nutrigenetics of omega-3 PUFAs is key to understanding the etiology, and developing effective preventive measures. In this review, we will summarize the current state of knowledge of genetic interactions with omega-3 PUFAs in modulating lipid metabolism and inflammation, and defining health outcomes. Nutrigenetics and nutrigenomics are still in their infancy with respect to CVD prediction and therapy. Integration of the progress in the omics, including metabolomics, lipidomics, transcriptomics, and proteomics, coupled with advances in nutrigenomic and nutrigenetic research will move us towards personalized medicine as the ultimate paradigm of responsible clinical practice.

Association of COL4A1 genetic polymorphisms with coronary artery disease in Uygur population in Xinjiang, China

Background

Type IV collagen is important for the structural integrity and function of basement membranes. Basement membranes surround vascular smooth muscle cells in the media, COL4A1 is the most abundant component of type IV collagen in all Basement membranes. However, the relationship between COL4A1 genetic polymorphisms and coronary artery disease (CAD) remains unclear. We performed a case–control study to explore the association of COL4A1 genetic polymorphisms with CAD in Uygur population of China.

Methods

1095 Uygur people (727 men, 368 women) including 471 CAD patients and 624 controls were selected for the present study. Two SNPs (rs605143 and rs565470) were genotyped by using the polymerase chain reaction-restriction fragment length (PCR-RFLP) method.

Results

For total and men, the rs605143 was found to be associated with CAD by in a dominate model (p = 0.014, p = 0.013, respectively). The difference remained statistically significant after multivariate adjustment (p = 0.036, p = 0.014, respectively). The rs565470 was also found to be associated with CAD in a recessive model for total and men (both p < 0.001), and the difference remained statistically significant after multivariate adjustment (P = 0.002, P = 0.001, respectively).

Conclusion

Both rs605143 and rs565470 of COL4A1gene are associated with CAD in Uygur population of China.

Conventional and novel diagnostic biomarkers of acute myocardial infarction: a promising role for circulating microRNAs

Biomarkers play a critical role in the diagnosis of acute myocardial infarction (AMI), especially in patients with atypical clinical and/or electrocardiographic presentation or co-morbidities, like the elderly. High-sensitivity assays based on specific biomarkers (e.g. cardiac troponins) enabling earlier AMI diagnosis have recently become available in clinical practice. Although no single biomarker of myocardial necrosis is ever likely to afford AMI diagnosis, a combination including different biomarkers for necrosis and ischemia, like new circulating molecules (microRNAs), could enhance diagnostic specificity. We review the recent literature on conventional and novel AMI biomarkers, with special emphasis on circulating microRNAs.

Gene-smoking interactions in multiple Rho-GTPase pathway genes in an early-onset coronary artery disease cohort

We performed a gene-smoking interaction analysis using families from an early-onset coronary artery disease cohort (GENECARD). This analysis was focused on validating and expanding results from previous studies implicating single nucleotide polymorphisms (SNPs) on chromosome 3 in smoking-mediated coronary artery disease. We analyzed 430 SNPs on chromosome 3 and identified 16 SNPs that showed a gene-smoking interaction at P < 0.05 using association in the presence of linkage--ordered subset analysis, a method that uses permutations of the data to empirically estimate the strength of the association signal. Seven of the 16 SNPs were in the Rho-GTPase pathway indicating a 1.87-fold enrichment for this pathway. A meta-analysis of gene-smoking interactions in three independent studies revealed that rs9289231 in KALRN had a Fisher's combined P value of 0.0017 for the interaction with smoking. In a gene-based meta-analysis KALRN had a P value of 0.026. Finally, a pathway-based analysis of the association results using WebGestalt revealed several enriched pathways including the regulation of the actin cytoskeleton pathway as defined by the Kyoto Encyclopedia of Genes and Genomes.

Disease-related growth factor and embryonic signaling pathways modulate an enhancer of TCF21 expression at the 6q23.2 coronary heart disease locus

Coronary heart disease (CHD) is the leading cause of mortality in both developed and developing countries worldwide. Genome-wide association studies (GWAS) have now identified 46 independent susceptibility loci for CHD, however, the biological and disease-relevant mechanisms for these associations remain elusive. The large-scale meta-analysis of GWAS recently identified in Caucasians a CHD-associated locus at chromosome 6q23.2, a region containing the transcription factor TCF21 gene. TCF21 (Capsulin/Pod1/Epicardin) is a member of the basic-helix-loop-helix (bHLH) transcription factor family, and regulates cell fate decisions and differentiation in the developing coronary vasculature. Herein, we characterize a cis-regulatory mechanism by which the lead polymorphism rs12190287 disrupts an atypical activator protein 1 (AP-1) element, as demonstrated by allele-specific transcriptional regulation, transcription factor binding, and chromatin organization, leading to altered TCF21 expression. Further, this element is shown to mediate signaling through platelet-derived growth factor receptor beta (PDGFR-β) and Wilms tumor 1 (WT1) pathways. A second disease allele identified in East Asians also appears to disrupt an AP-1-like element. Thus, both disease-related growth factor and embryonic signaling pathways may regulate CHD risk through two independent alleles at TCF21.

Genetics 100 for cardiologists: basics of genome-wide association studies

The spring of 2012 marked the fifth anniversary of the widespread appearance in the biomedical literature of genome-wide association studies (GWAS) of diseases of adulthood. Articles reporting GWAS results now regularly appear in dozens of general medicine and cardiology journals. As of August 2012, more than 1700 published GWAS have reported findings across a range of human diseases. Many of these reported new genetic determinants of cardiovascular disease, including coronary artery disease and its risk factors such as diabetes, dyslipidemia, and hypertension. Though GWAS reports follow a standard format, superficially they can appear intimidating to most nongeneticists, whom we suspect often skip over them. Considering the importance of GWAS in cardiovascular science and medicine, and because they show no signs of fading, it is important for cardiovascular medical personnel and scientists to understand GWAS fundamentals. In this article, we provide a roadmap for the nonexpert reader to navigate through GWAS of cardiovascular disease. We cover the basic essentials needed to understand GWAS: underlying theory, mechanics, analysis and display, interpretation, and relevance. Areas covered include the relationship between GWAS and standard epidemiologic study design, the concepts of DNA sequence variation and linkage disequilibrium, the particular statistical considerations in studies involving many independent variables and large sample sizes, the meaning and interpretation of Manhattan plots, and the biologic and clinical significance of GWAS-based discoveries. We conclude with comments about the limitations of GWAS and about what to look for in the "post-GWAS era."

The links between complex coronary disease, cerebrovascular disease, and degenerative brain disease

Our appreciation of the complexity of cardiovascular disease is growing rapidly. Consistent with the fact that the vasculature is an omnipresent system that carries blood to every organ in the body, an expanding number of conditions are now known to be directly associated with disturbed cardiovascular function or vascular pathology. In particular, cardiovascular disease has recently been implicated as playing a major role in dementia and other forms of degenerative brain disease. Here, we explore some of the many emerging relationships between cardiovascular risk factors, complex coronary artery disease, cerebrovascular disease, and degenerative brain disease.