Genome-wide association study of coronary artery disease

High Expression Levels of the SOCS3 Gene Are Associated with Acute Myocardial Infarction

Aims: The present study was designed to evaluate whether the expression of the suppressor of cytokine signaling 3 (SOCS3) gene could serve as a biomarker to predict the risk of acute myocardial infarction (AMI). Basic Methods: Peripheral white blood cells were collected from 113 patients with AMI and 92 patients with stable coronary artery disease (SCAD). SOCS3 mRNA expression levels in peripheral blood cells were determined by a real-time quantitative polymerase chain reaction, and levels of the SOCS3 protein were determined by Western blotting. Results: The mRNA expression levels of the SOCS3 gene in AMI patients was 1.33-fold higher than that in the SCAD patients, and the level of the SOCS3 protein was 1.25-fold higher (p < 0.05 for both). Bivariate logistic regression analysis documented that elevated expression of the SOCS3 gene was an independent risk factor for AMI. A regression analysis demonstrated a lack of correlation between elevated expression levels of SOCS3 and the levels of fasting blood glucose high- and low-density lipoprotein, and cardiac troponin. Conclusions: Elevated expression of the SOCS3 gene results most likely from enhanced inflammatory responses and is an independent risk factor for AMI.

Sorting nexin 1 loss results in increased oxidative stress and hypertension

Acute renal depletion of sorting nexin 1 (SNX1) in mice results in blunted natriuretic response and hypertension due to impaired dopamine D₅ receptor (D₅ R) activity. We elucidated the molecular mechanisms for these phenotypes in Snx1^-/- mice. These mice had increased renal expressions of angiotensin II type 1 receptor (AT₁ R), NADPH oxidase (NOX) subunits, D₅ R, and NaCl cotransporter. Basal reactive oxygen species (ROS), NOX activity, and blood pressure (BP) were also higher in Snx1^-/- mice, which were normalized by apocynin, a drug that prevents NOX assembly. Renal proximal tubule (RPT) cells from hypertensive (HT) Euro-American males had deficient SNX1 activity, impaired D₅ R endocytosis, and increased ROS compared with cells from normotensive (NT) Euro-American males. siRNA-mediated depletion of SNX1 in RPT cells from NT subjects led to a blunting of D₅ R agonist-induced increase in cAMP production and decrease in Na⁺ transport, effects that were normalized by over-expression of SNX1. Among HT African-Americans, three of the 12 single nucleotide polymorphisms interrogated for the SNX1 gene were associated with a decrease in systolic BP in response to hydrochlorothiazide (HCTZ). The results illustrate a new paradigm for the development of hypertension and imply that the trafficking protein SNX1 may be a crucial determinant for hypertension and response to antihypertensive therapy.

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.

"Desert" gene (Chr9p21) variants as novel markers for coronary artery disease

OBJECTIVE

Previous reports have denoted to the possible link of Chr9p21 locus to the incidence of coronary artery disease (CAD). The entire core of chr9p21 is covered by "ANRIL" (Antisense noncoding RNA in INK4 Locus) and lies in a region that is free from any coding proteins; therefore, it is called the desert gene. The major objectives of this study were to examine the association of rs10757278 and rs2383206 SNPs on Chr9p21 with the incidence of CAD in the presence and absence of type 2 diabetes (T2D) in Egyptians and to correlate these genetic variants with several disease biomarkers (TC, CRP, and HbA1c).

METHODS

The study subjects consisted of 150 subjects; 50 healthy controls and 100 patients that were divided into two groups; CAD patients and CAD T2D patients. The genotyping of SNPs was performed using qPCR.

RESULTS

Genotype distribution for both SNPs were found to be significantly different (p=0.0009 for rs10757278 and p=0.001 for rs2383206) between patients and controls. The allele frequency was also different for rs10757278.

CONCLUSION

The current study showed that rs10757278/rs2383206-G allele increases the risk for CAD in Egyptians. Moreover, AA variant appeared as a protective genotype. However, SNPs did not noticeably contribute in the elevation of TC, hs-CRP, and HbA1c in non-diabetic and diabetic CAD patients.

A molecular case-control study of association of HNF1A gene polymorphisms (rs2259816 and rs7310409) with risk of coronary artery disease in Iranian patients

BACKGROUND

Coronary artery disease (CAD) is the one of the most common heart diseases, being the main factor of mortality and morbidity worldwide. CAD has been known as a multifactorial disease and its progression depends on genetic and environmental factors. Numerous studies have shown evidence for association between 12q24.3 locus and CAD.

OBJECTIVES

In the present study, the association of two HNF1A polymorphisms, rs2259816 and rs7310409, located on 12q24.3 locus with CAD was investigated in Iranian patients.

METHODS

Whole genomic DNA was isolated from peripheral blood obtained from 411 Iranian volunteer. Then, the polymorphisms rs2259816 and rs7310409 located on 12q24.3 locus were genotyped using TaqMan Probe Real Time PCR. Statistical analysis was performed by SPSS software, version 19.

RESULTS

rs2259816 (p-value = 0.006) and rs7310409 (p-value = 0.001) showed statistically significant association with CAD risk. Our results indicated that there was a significant correlation between rs2259816 and blood triglyceride. However, no correlation was found between rs2259816, rs7310409 and other CAD risk factors.

Analysis of rs6725887 in the WD Repeat Protein 12 in Association with Coronary Artery Disease in Iranian Patients

Although genetic variants that affect susceptibility to coronary artery disease (CAD) have been greatly known, a number of these single nucleotide polymorphisms (SNPs) remain to be analyzed in populations with different ethnicities. CAD is influenced by numerous genetic, environmental, and lifestyle factors, and is an important reason for mortality around the globe. In this study, a novel SNP (rs6725887) in the WD Repeat Protein 12 (WDR12) gene was selected to be examined in Iranian patients with CAD. Ninety eigth healthy controls and one hundred and one CAD patients were enrolled from Iranian population, and their clinical data were collected for further comparisons. After DNA extraction from each sample, genotypes were characterized by Taq Man probe real- time PCR assay. Statistical analyses were performed to evaluate genotype and allele frequencies and compared the values with clinical variables. Body mass index, blood pressure, fasting blood sugar, LDL, HDL, cholesterol, and triglyceride significantly differed in CAD and control groups. Genotype and allele frequencies of rs6725887 in CAD patients and controls showed no significant association in the distribution. However, clinical parameters of CAD patients like HDL, LDL, FBS, TG, DBP and SBP had significantly (P<0.05) higher levels compared to control group. The rs6725887 polymorphism is unlikely to play a key role in CAD risk in our population. Further additional samples are required for better appreciation of the influence of WDR12 SNP on CAD occurrence.

Variation in the sodium-dependent vitamin C transporter 2 gene is associated with risk of acute coronary syndrome among women

Background

Vitamin C is associated with a lower risk of coronary heart disease possibly due to its anti-oxidative effects, beneficial effects on endothelial function and importance in collagen synthesis. The sodium-dependent vitamin C transporter 2 is responsible for the transport of vitamin C into various cells and malfunction of this protein leads to reduced vitamin C in tissue, including the arterial wall. We tested the hypothesis that candidate variations rs6139591 and rs1776964 in the gene coding for sodium-dependent vitamin C transporter 2 are associated with development of acute coronary syndrome.

Design

In the Danish Diet, Cancer and Health cohort study, we performed a case-cohort study among 57,053 subjects aged 50–64 years.

Results

During a mean follow-up period of 6.4 years, we identified 936 cases and randomly selected a sub-cohort (n = 1,580) with full information on genotypes and covariates. Using Cox proportional hazard models, we found that women with the rs6139591 TT genotype and a lower than median dietary vitamin C intake had a higher risk of acute coronary syndrome compared with those with the CC genotype (adjusted HR 5.39, 95% confidence interval, 2.01–14.50). We also observed a not as strong but positive although inconsistent association for women at a higher than median intake of vitamin C rich food. For the rs1776964 polymorphism, we found a higher risk (adjusted HR 3.45, 95% CI, 1.16–10.28) among TT-homozygous women with higher than median vitamin C intake compared with the CC genotype and low vitamin C intake. Among men, weaker and non-significant associations were observed for both polymorphisms.

Conclusion

Genetic variation in the sodium-dependent vitamin C transporter 2 is associated with risk of incident acute coronary syndrome in women. The genotype effects may not be fully compensated by a higher intake of vitamin C rich food.

The rs10757278 polymorphism of the 9p21.3 locus is associated with premature coronary artery disease in Polish patients

Recently, genome-wide association studies have revealed a locus associated with coronary artery disease (CAD) and myocardial infarction, namely, 9p21.3. Its participation in the conditioning of the disease has been proven in many populations of European descent, but not yet in Slavs. Allelic variants of the rs10757278 polymorphism functionally affect the activity of the 9p21.3 locus; therefore, we conducted a study to determine whether the rs10757278 is associated with premature CAD in Polish patients. We studied 320 subjects aged 25-55 years, divided into two groups matched by sex and age: (1) patients with angiographically proven premature CAD (n=160), and (2) blood donors as a control group (n=160). The rs10757278 was genotyped using the method of fluorescently labeled allele-specific oligonucleotides. The frequency of the G allele was significantly higher in patients than in controls (58.2% vs. 42.8%, respectively, p=0.011) and was similar to the frequency of the GG homozygotes (30.6% vs. 17.5%, respectively, p=0.006). Both the GG homozygosity (odds ratio [OR]=2.08, 95% confidence interval [CI]: 1.19-3.66) as well as the G allele (OR=1.49, 95% CI: 1.08-2.07) have been associated with CAD in the analyzed population. These variants may be considered as risk factors, also in the Polish population.

The effect of hepatic lipase on coronary artery disease in humans is influenced by the underlying lipoprotein phenotype

Increased or decreased hepatic lipase (HL) activity has been associated with coronary artery disease (CAD). This is consistent with the findings that gene variants that influence HL activity were associated with increased CAD risk in some population studies but not in others. In this review, we will explain the conditions that influence the effects of HL on CAD. Increased HL is associated with smaller and denser LDL (sdLDL) and HDL (HDL(3)) particles, while decreased HL is associated with larger and more buoyant LDL and HDL particles. The effect of HL activity on CAD risk is dependent on the underlying lipoprotein phenotype or disorder. Central obesity with hypertriglyceridemia (HTG) is associated with high HL activity that leads to the formation of sdLDL that is pro-atherogenic. In the absence of HTG, where large buoyant cholesteryl ester-enriched LDL is prominent, elevation of HL does not raise the risk for CAD. In HTG patients, drug therapy that decreases HL activity selectively decreases sdLDL particles, an anti-atherogenic effect. Drug therapy that raises HDL(2) cholesterol has not decreased the risk for CAD. In trials where inhibition of cholesterol ester transfer protein (CETP) or HL occurs, the increase in HDL(2) most likely is due to inhibition of catabolism of HDL(2) and impairment of reverse cholesterol transport (RCT). In patients with isolated hypercholesterolemia, but with normal triglyceride levels and big-buoyant LDL particles, an increase in HL activity is beneficial; possibly because it increases RCT. Drugs that lower HL activity might decrease the risk for CAD only in hypertriglyceridemic patients with sdLDL by selectively clearing sdLDL particles from plasma, which would override the potentially pro-atherogenic effect on RCT. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).

A novel integrative network approach to understand the interplay between cardiovascular disease and other complex disorders

There is accumulating evidence that the proteins encoded by the genes associated with a common disorder interact with each other, participate in similar pathways and share GO terms. It has been anticipated that the functional modules in a disease related functional linkage network can be integrated with bibliomics to reveal association with other complex disorders. In this study, the cardiovascular disease functional linkage network (CFN) containing 1536 nodes and 3345 interactions was constructed using proteins encoded by 234 genes associated with the disease. Integration of CFN with bibliomics showed that 227 out of 566 functional modules are significantly associated with one or more diseases. Analysis of functional modules revealed the possible regulatory roles of SP1 and CXCL12 in the pathogenesis of cardiovascular disease (CVD) and modulation of their activities may be considered as potential therapeutic tools. The integration of CFN with bibliomics also indicated significant relations of CVD with other complex disorders. In a stratified map the members of 227 functional modules and 58 diseases in 15 disease classes were combined. In this map, leprosy, listeria monocytogenes, myasthenia, hemorrhagic diathesis and Protein S deficiency, which were not previously reported to be associated with CVD, showed significant associations. Several cancers arising from epithelial cells were also found to be linked to other diseases through hub proteins, VEGFA and PTGS2.