The association of eight potentially functional polymorphisms in five adrenergic receptor-encoding genes with myocardial infarction risk in Han Chinese

Association of an ADRB3 Variant with Coronary Artery Disease Within the Chinese Han Population: Construction of a Predictive Nomogram Model

Objective: Coronary artery disease (CAD) is a the most common type of heart disease, and is associated with the highest mortality rate. The role of the β₃-adrenergic receptor gene (ADRB3) in energy homeostasis and lipolysis suggests that it may be associated with obesity, insulin resistance, diabetes, and hypertension. Herein, we sought to examine the relationship between CAD and variants of the ADRB3 gene in individuals with Han and Uygur ethnicities in China. Methods: All 1022 participants were genotyped for two ADRB3 single nucleotide polymorphisms (SNPs; rs1892818 and rs9693898) using real-time polymerase chain reaction (TaqMan). Uygur (259 CAD patients, 161 control group) and Han (308 CAD patients, 294 control group) were included in two case-control studies. We subsequently developed a predictive model using ADRB3 genetic variation and clinical variables to predict risk of CAD. Results: The rs1892818 CT genotype (8.5% vs 3.9%, p = 0.019) and T allele (4.3% vs 1.9%, p = 0.021) were more frequently detected in the control subjects compared to CAD patients of the Han population but not in the Uygur population. The rs9693898 was not associated with CAD in either ethnic population. Logistic regression analysis further demonstrated that carriers of the rs1892818 CT genotype had a lower risk of CAD than did those with the CC genotype (CT vs CC, p = 0.044, odds ratio [OR] = 0.441, 95% confidence interval [CI]: 0.199-0.976). Using this data, we constructed a predictive nomogram model for CAD with an area under the curve (95% CI) of 0.722 (0.682, 0.761). Conclusions: Our results suggest that rs1892818 is associated with CAD in the Han population and that the CT genotype of rs1892818 may serve as a protective factor for CAD in Han individuals. The proposed nomograms can be used for the prediction of CAD in this population.

Expression of the β1-adrenergic receptor (ADRB1) gene in the myocardium and β-adrenergic reactivity of the body in patients with a history of myocardium infraction

β1-adrenergic receptors (β1-AR) directly affect on intracardiac hemodynamic and the ability of the heart to tolerate physical activity by regulating its inotropic and chronotropic functions. Severe hypersympathicotonia, specific to coronary artery disease (CAD) and chronic heart failure (HF), leads to impaired functioning of β1-AR. The aim of this research was to assess the expression level of the β1-AR ADRB1 gene in the myocardium, to evaluate the β-adrenergic reactivity of the membrane (β-ARM) of erythrocytes, and to analyze the association of these parameters with myocardial contractile dysfunction in patients with a myocardial infarction (MI) in the past and without it. The study included 126 patients with chronic CAD. Among the patients, 55.6 % had a history of MI at least 6 months ago. The expression of the ADRB1 gene was assessed using real-time polymerase chain reaction. With this purpose, we isolated RNA from the right atrial appendage, which was excised when a heart-lung machine was connected during a planned coronary bypass surgery. β-ARM was evaluated in 57 patients. This method is based on the fact of inhibition of hemolysis of erythrocytes, placed in a hyposmotic medium, in the presence of a β-blocker. Within the whole sample of patients, the expression of the ADRB1 gene is comparable in different functional classes of HF. There was no linear correlation between the expression of the ADRB1 gene and left ventricle ejection fraction (LVEF). In patients with a history of MI, the expression of the ADRB1 gene was elevated when compared to a group of patients without MI (p = 0.017). Patients with a history of MI had higher values of β-ARM than those without MI (p = 0.017). The reverse correlation between β-ARM and LVEF (r = -0,570, p = 0,002) was revealed in the group of patients without MI but not in the group of patients with a history of MI (r = -0,137, p = 0,479). In the sample of patients with chronic CAD, in the myocardium of subjects with a history of MI, the relative expression of ADRB1 gene was higher compared to the group of patients without MI. In patients with different functional classes (FC) of HF and with different ejection fraction, both with MI and without it, ADRB1 gene expression was comparable. In the group of patients with a history of MI, an increase in β-ARM was observed, i.e. decrease in the number or sensitivity of β-AR. Among patients without MI, an inverse correlation was found between β-ARM and LVEF.

Association of genetic defects in the apelin-AGTRL1 system with myocardial infarction risk in Han Chinese

We aimed to test the hypothesis that apelin (APLN) and its receptor AGTRL1 (APLNR) genes may contribute to the pathogenesis of myocardial infarction in Han Chinese. This is a hospital-based, case-control association study, involving 1067 patients with myocardial infarction and 942 healthy controls. Myocardial infarction is diagnosed by electrocardiogram or anatomopathological examination. Eight polymorphisms in APLN gene and 5 in APLNR gene were genotyped using the TaqMan assay. Risk was summarized as odds ratio (OR) and 95% confidence interval (CI). In males, rs56204867-G allele (adjusted OR, 95% CI, p: 0.21, 0.08-0.55, 0.002) and rs2235309-T allele (0.60, 0.42-0.84, 0.004) was associated with a significantly reduced risk of myocardial infarction, and the mutations of rs2235310 was associated with an increased risk (1.41, 1.06-2.52, 0.021), as well as for rs948847-GG genotype (1.85, 1.23-2.91, 0.007). In females, the presence of rs56204867-AG and -GG genotypes was significantly associated with 44% and 50% reduced risk (0.56 and 0.50, 0.40-8.04 and 0.29-0.86, 0.007 and 0.036), respectively; for rs2235310, CC genotype was associated with 72% increased risk (1.72, 1.09-3.22, 0.016), and the odds of myocardial infarction was 3.47 for rs9943582-TT genotype (95% CI: 1.53-7.57, 0.009). The gender-specific association of APLN and APLNR genes with myocardial infarction was reinforced by further linkage and haplotype analyses. Finally, nomograms based on significant polymorphisms are satisfactory, with the C-indexes over 80% for both genders. Taken together, our findings indicate that APLN and APLNR genes are potential candidates in the pathogenesis of myocardial infarction in Han Chinese, and importantly their contribution is gender-dependent.

Stratified meta-analysis by ethnicity revealed that ADRB3 Trp64Arg polymorphism was associated with coronary artery disease in Asians, but not in Caucasians

BACKGROUND

Previous studies demonstrated that ADRB3, beta-3 adrenergic receptor, participated in lipolysis and thermogenesis in adipose tissue. Consequently, this gene has attracted an increasing number of genetic studies examining its association with coronary artery disease (CAD) in different ethnicities in recent years, but no conclusion has been reached so far. The aim of this study was to explore whether the well-studied locus ADRB3 Trp64Arg in this gene confers a race-specific effect to CAD by conducting a stratified meta-analysis involving 15 independent studies and 11,802 subjects.

METHODS

Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the strength of association. Publication bias was quantified and examined with Begg's funnel plot test and Egger's linear regression method. The overall meta-analysis or stratified meta-analysis by ethnicity was performed by using STATA 12.0 software.

RESULTS

A total of 15 eligible studies involving 5779 CAD cases and 6023 health controls were included in this meta-analysis. The pooled results indicated that ADRB3 Trp64Arg polymorphism was significantly associated with an increased risk of CAD. Further stratified analysis by ethnicity revealed that ADRB3 Trp64Arg polymorphism was significantly associated with CAD in Asians (allelic: OR = 1.48, 95%CI 1.13-1.94, P = .005; homozygous: OR = 2.66, 95%CI 1.87-3.77, P < .001; recessive: OR = 2.46, 95%CI 1.74-3.47, P < .001), but not in Caucasians (allelic: OR = 1.09, 95%CI 0.93-1.27, P = .290; homozygous: OR = 1.31, 95%CI 0.61-2.86, P = .490; recessive: OR = 1.31, 95%CI 0.60-2.84, P = 2.494).

CONCLUSIONS

This meta-analysis suggests that ADRB3 Trp64Arg polymorphism confers a race-specific effect to CAD.

Genetic variability of five ADRB2 polymorphisms among Mexican Amerindian ethnicities and the Mestizo population

The Mexican population is characterized by high and particular admixture, and the picture of variants associated with disease remains unclear. Here we investigated the distribution of single nucleotide polymorphisms (SNPs) in the Mexican population. We focused on two non-synonymous and three synonymous SNPs in the beta-2 adrenergic receptor gene (ADRB2), which plays key roles in energy balance regulation. These SNPs were genotyped in 2,011 Mexican Amerindians (MAs) belonging to 62 ethnic groups and in 1,980 geographically matched Mexican Mestizos (MEZs). The frequency distribution of all five ADRB2 variants significantly differed between MAs, MEZs, and other continental populations (CPs) from the 1000 Genomes database. Allele frequencies of the three synonymous SNPs rs1042717A, rs1042718A, and rs1042719C were significantly higher in Mexican individuals, particularly among MAs, compared to in the other analyzed populations (P<0.05). The non-synonymous ADRB2 Glu27 allele (rs1042714G), which is associated with several common conditions, showed the lowest frequency in MAs (0.03) compared to other populations worldwide. Among MEZs, this allele showed a frequency of 0.15, intermediate between that in MAs and in Iberians (0.43). Moreover, Glu27 was the only SNP exhibiting a geographic gradient within the MEZ population (from 0.22 to 0.11), reflecting admixed mestizo ancestry across the country. Population differentiation analysis demonstrated that Glu27 had the highest F_ST value in MAs compared with Europeans (CEU) (0.71), and the lowest between MAs and Japanese (JPT) (0.01), even lower than that observed between MAs and MEZs (0.08). This analysis demonstrated the genetic diversity among Amerindian ethnicities, with the most extreme F_ST value (0.34) found between the Nahuatls from Morelos and the Seris. This is the first study of ADRB2 genetic variants among MA ethnicities. Our findings add to our understanding of the genetic contribution to variability in disease susceptibility in admixed populations.

Pragmatic Analysis of Dyslipidemia Involvement in Coronary Artery Disease: A Narrative Review

Background

Dyslipidemia is the main factor involved in the occurrence and progression of coronary artery disease.

Objective

The research strategy is aimed at analyzing new data on the pathophysiology of dyslipidemia involvement in coronary artery disease, the modalities of atherogenic risk estimation and therapeutic advances.

Methods

Scientific articles published in PubMed from January 2017 to February 2018 were searched using the terms “dyslipidemia” and “ischemic heart disease”.

Results

PCSK9 contributes to the increase in serum levels of low-density lipoprotein-cholesterol and lipoprotein (a). The inflammation is involved in the progression of hyperlipidemia and atherosclerosis. Hypercholesterolemia changes the global cardiac gene expression profile and is thus involved in the increase of oxidative stress, mitochondrial dysfunction, and apoptosis initiated by inflammation. Coronary artery calcifications may estimate the risk of coronary events. The cardio-ankle vascular index evaluates the arterial stiffness and correlates with subclinical coronary atherosclerosis. The carotid plaque score is superior to carotid intima-media thickness for risk stratification in patients with familial hypercholesterolemia and both can independently predict coronary artery disease. The lipoprotein (a) and familial hypercholesterolemia have a synergistic role in predicting the risk of early onset and severity of coronary atherosclerosis. A decrease in atherosclerotic coronary plaque progression can be achieved in patients with plasma LDL-cholesterol levels below 70 mg/dL. A highly durable RNA interference therapeutic inhibitor of PCSK9 synthesis could be a future solution.

Conclusion

The prophylaxis and treatment of coronary artery disease in a dyslipidemic patient should be based on a careful assessment of cardio-vascular risk factors and individual metabolic particularities, so it may be personalized.

Depletion of β3-adrenergic receptor induces left ventricular diastolic dysfunction via potential regulation of energy metabolism and cardiac contraction

Left ventricular diastolic dysfunction (LVDD) is a central perturbation in heart failure with preserved ejection fraction, and there are currently no effective remedies to improve LVDD in clinical practice. The β3-adrenergic receptor (ADRB3) was reported to play protective effects on inhibiting myocardial fibrosis in response to hemodynamic stress. However, the effects of ADRB3 on LVDD and its underlying mechanisms are still undefined. In the current study, the role of ADRB3 in LVDD was identified in ADRB3-knockout mice. Echocardiography parameters showed that depletion of ADRB3 had little effect on cardiac systolic function but obviously led to cardiac diastolic dysfunction in vivo. Proteomics (including the global proteome, phosphorylated and acetylated proteome) and bioinformatics analysis (including GO analysis, KEGG pathway analysis, GO-Tree network, Pathway-Act network, and protein-protein interaction network) were performed on cardiac specimens of ADRB3-KO mice and wild-type mice. The results showed that the cardiac energy metabolism (especially the citrate cycle), actin cytoskeleton organization, and cardiac muscle contraction (related to mitogen-activated protein kinase, toll-like receptor, and ErbB signalling pathway) were potential core mechanisms underlying ADRB3-KO-induced LVDD. In addition, the protein-protein interaction network indicated that the core proteins associated with ADRB3-KO-induced LVDD were FGG, ALDH1A1, FGA, APOC3, SLC4A1, SERPINF2, HP, CTNNB1, and TKT. In conclusion, the absence of ADRB3 leads to LVDD, which is potentially associated with the regulation of cardiac energy metabolism, actin cytoskeleton organization, and cardiac muscle contraction.

β2-Adrenergic Receptor Gene Polymorphisms Are Associated with Cardiovascular Events But not All-Cause Mortality in Coronary Artery Disease Patients: A Meta-Analysis of Prospective Studies

Aims: β-Adrenergic receptors (ADRBs) play a pivotal role in cardiovascular disease. Recently, genetic polymorphisms of ADRB1 and ADRB2 have been suggested to be associated with cardiovascular events and all-cause mortality in coronary artery disease (CAD) patients, but the results of relevant studies are inconsistent and controversial. Therefore, we performed a meta-analysis to investigate the association between ADRB1 and ADRB2 polymorphisms with cardiovascular events and all-cause mortality in CAD patients.

Materials and Methods: The PubMed, Ovid, EMBASE, Cochrane, and CINAHL databases were searched for eligible studies published before April 2018. A total of 5495 patients from eight studies were included in our meta-analysis.

Results: We found that CAD patients harboring the ADRB2 rs1042714 Glu27 allele exhibited a positive association with cardiovascular events (risk ratio [RR] = 1.31, 95% confidence interval [CI]: 1.08–1.58, p = 0.006), but not with all-cause mortality (RR = 0.97, 95% CI: 0.70–1.35, p = 0.859), compared with patients who were Gln27 homozygotes. No other significant associations were observed between ADRB1 (rs1801252, rs1801253), ADRB2 (rs1042713, rs1800888) polymorphisms and cardiovascular events or all-cause mortality in CAD patients.

Conclusion: This study suggests that the identified ADRB2 polymorphism could influence the outcomes of CAD patients, showing important clinical value.