Polymorphisms in the paraoxonase and endothelial nitric oxide synthase genes and the risk of early-onset myocardial infarction

Paraoxonase 1 Gene L55M Polymorphism and Paraoxonase 1 Activity in Obstructive Sleep Apnea Patients

The antioxidant enzyme paraoxonase-1 (PON1) may limit oxidative stress in the development of cardiovascular diseases (CVD) and obstructive sleep apnea (OSA). The aim of the study was to determine PON1 gene L55M polymorphism in OSA-positive and OSA-negative subjects, along with paraoxonase activity of the enzyme (PON1-act). Caucasians aged 25-75, with BMI 19.0-53.0 kg/m² and no acute or severe chronic disorder underwent polysomnography, and OSA-negative (n = 44) and OSA-positive (n = 57) groups were established. The following parameters were assessed: arterial blood pressure and serum glucose, lipids, C-reactive protein, and homocysteine. Genomic DNA was extracted and amplified, and automatic sequencing was used to confirm the LL, LM, MM genotypes. PON1-act was measured spectrophotometrically using paraoxon as a substrate. We found that frequency of polymorphisms differed significantly between the OSA-negative and OSA-positive patients (p < 0.05). Increased PON1-act was observed in the LL-genotype versus the LM + MM-genotype in the study population (p < 0.05). PON1-act was higher in the OSA-negative compared with OSA-positive patients (p < 0.001); in general and in the subgroups presenting the LL or LM genotype. In addition, there was an inverse relationship between PON1-act and LDL-cholesterol in the entire study population. The OSA-positive group presented an inverse relationship between PON1-act and fasting glucose. We conclude that patients could benefit from the LL genotype related with higher activity of PON1. OSA pathology might decrease the enzyme activity, despite the presence of L allele.

Angiogenesis related genes NOS3, CD14, MMP3 and IL4R are associated to VEGF gene expression and circulating levels in healthy adults

BACKGROUND

Vascular endothelial growth factor (VEGF) plays a key role in angiogenesis. The aim was to assess the genetic connections between the angiogenesis-related NOS3, CD14, MMP3, IL4R, IL4 genes and VEGF expression and plasma levels.

METHODS

The associations between VEGF plasma levels with the polymorphisms of NOS3, CD14, MMP3, IL4R, and IL4 were assessed in 403 healthy unrelated adults. The epistatic and environmental interactions were explored, including four VEGF-related polymorphisms previously identified. The VEGF expression in peripheral blood mononuclear cells was quantified (n = 65) for the VEGF121, VEGF145, VEGF165, and VEGF189 isoforms.

RESULTS

The polymorphism rs1799983 of NOS3 was associated with the sum of all VEGF isoforms mRNA levels (P = 0.032) and VEGF145 (P = 0.033). Rs1800779 of NOS3 interacted with rs3918226 of the same gene and with the rs2569190 of CD14 (P = 0.022, P = 0.042, respectively) for VEGF plasma levels. Other epistatic interactions included the rs1801275 of IL4R with the rs6921438 (VEGF-related variant) and rs3025058 of MMP3 (P = 0.042, P = 0.010 respectively) and the rs2569190 of CD14 with the rs3025058 of MMP3 (P = 0.0119). We also identified an interaction of rs1800779 with obesity, high-density lipoprotein cholesterol and triglycerides (P = 0.018, P = 0.005, P = 0.043, respectively) as well as the interaction of rs6921438 with hypertension (P = 0.028).

CONCLUSIONS

Our findings indicated that genetic variants of NOS3, CD14, MMP3 and IL4R are implicated in the determination of VEGF expression and plasma levels. Thus, they support the hypothesis that in physiological conditions there are complex biological relationships between pathways (such as angiogenesis and inflammation), which are involved in the development of chronic diseases.

The influence of renal function on the association of rs854560 polymorphism of paraoxonase 1 gene with long-term prognosis in patients after myocardial infarction

Paraoxonase 1 (PON1) is an enzyme responsible for the antioxidant properties of high density lipoprotein (HDL). The activity of PON1 is decreased in patients with coronary artery disease, myocardial infarction or chronic kidney disease. rs662 and rs854560 are single nucleotide polymorphisms (SNPs) associated with PON1 activity and 10-year cardiovascular mortality of patients with stable coronary artery disease. We investigated the association of rs662 and rs854560 SNPs of the PON1 gene with 5-year mortality in patients with ST-elevation myocardial infarction (STEMI) treated invasively. We analyzed the data of consecutive patients with STEMI treated with primary PCI. Genotyping was performed with the TaqMan method. The analyzed end-point was total 5-year mortality. Additional subgroup analysis was performed for survival of patients depending on their eGFR. The study group comprised 634 patients (mean age 62.3 ± 11.85 years; 25.2 % of women, n = 160; PCI successful in 92.3 %, n = 585). No clinically relevant differences in baseline characteristics were found between the genotypes. No association between either genotype and 5-year mortality was found: p = 0.4 for the rs662 SNP, p = 0.73 for the rs854560 one (log-rank test). However, in a subgroup of patients with eGFR below median value (78.6 ml/min/1.73m2) the rs854560 AA homozygotes had a significantly lower probability of survival (p = 0.047, log-rank test). The AA genotype of the rs854560 SNPs of the PON1 gene is associated with increased mortality in patients after myocardial infarction in the subpopulation of patients with lowered eGFR. This phenomenon may be explained by potentially lower PON1 activity in kidney disease.

Protein biomarkers of new-onset cardiovascular disease: prospective study from the systems approach to biomarker research in cardiovascular disease initiative

OBJECTIVE

Incorporation of novel plasma protein biomarkers may improve current models for prediction of atherosclerotic cardiovascular disease (ASCVD) risk.

APPROACH AND RESULTS

We used discovery mass spectrometry (MS) to determine plasma concentrations of 861 proteins in 135 myocardial infarction (MI) cases and 135 matched controls. Then, we measured 59 markers by targeted MS in 336 ASCVD case-control pairs. Associations with MI or ASCVD were tested in single-marker and multiple-marker analyses adjusted for established ASCVD risk factors. Twelve single markers from discovery MS were associated with MI incidence (at P<0.01), adjusting for clinical risk factors. Seven proteins in aggregate (cyclophilin A, cluster of differentiation 5 molecule [CD5] antigen-like, cell-surface glycoprotein mucin cell surface associated protein 18 [MUC-18], collagen-α 1 [XVIII] chain, salivary α-amylase 1, C-reactive protein, and multimerin-2) were highly associated with MI (P<0.0001) and significantly improved its prediction compared with a model with clinical risk factors alone (C-statistic of 0.71 versus 0.84). Through targeted MS, 12 single proteins were predictors of ASCVD (at P<0.05) after adjusting for established risk factors. In multiple-marker analyses, 4 proteins in combination (α-1-acid glycoprotein 1, paraoxonase 1, tetranectin, and CD5 antigen-like) predicted incident ASCVD (P<0.0001) and moderately improved the C-statistic from the model with clinical covariates alone (C-statistic of 0.69 versus 0.73).

CONCLUSIONS

Proteomics profiling identified single- and multiple-marker protein panels that are associated with new-onset ASCVD and may lead to a better understanding of underlying disease mechanisms. Our findings include many novel protein biomarkers that, if externally validated, may improve risk assessment for MI and ASCVD.

Polymorphisms of the NOS3 gene and risk of myocardial infarction in the Tunisian population

Controversial results regarding the association of eNOS gene (NOS3) polymorphisms with myocardial infarction (MI) have been reported. This study investigated the relationship of the -786T>C (rs2070744), 894G>T (rs1799983) and 4a4b polymorphisms of the NOS3 gene with the presence of MI in the Tunisian population. In addition, we also examined the association of NOS3 gene haplotypes with MI in Tunisian subjects. A total of 303 patients with MI and 225 controls were included in the study. The 894G>T and -786T>C single nucleotide polymorphisms were analyzed by PCR-RFLP, and 4a4b polymorphism just for PCR. There was significant linkage disequilibrium between the three NOS3 polymorphisms (p<0.0001). The genotype distribution and allele frequency of NOS3 4a4b, but not -786T>C and 894G>T, polymorphism was significantly different between MI patients and controls. The univariate logistic regression analysis showed a significant association of the 4a4b polymorphism and MI according to co-dominant, dominant and recessive models (co-dominant model OR: 4.38, 95%CI: 1.24-15.41; p=0.021, dominant model OR: 1.66, 95%CI: 1.14-2.42); p=0.007, and recessive model OR: 3.85, 95%CI: 1.10-13.47; p=0.035). The multivariate analysis, adjusted for traditional cardiovascular risk factors, revealed that the NOS3 4a4a genotype was an independent predisposing factor to MI, according to the models considered. In addition, a haplotype 7 (C-T-4a), (OR=12.05, p=0.010) was a risk factor of MI after controlling for classical risk factors. These finding suggest that the 4a4b polymorphism of the NOS3 gene was associated with MI in Tunisian patients.

Serum Paraoxonase (PON1) Activity in North-West Indian Punjabi's with Acute Myocardial Infarction

Human serum paraoxonase-1 (PON1), an enzyme on HDL prevents oxidation of LDL thereby preventing the development of atherosclerosis. Studies done so far have lead to conflicting results. As studies are lacking in North-West Indian Punjabi's, a distinct ethnic group with high incidence of coronary artery disease, we determined PONase activity in this population. It has been postulated that sudden lowering of serum PONase may lead to precipitation of acute myocardial infarction. We determined serum PONase activity and lipids in 100 patients each of AMI (within 24 h of onset), stable CAD and 100 age and sex matched healthy controls. These were again determined after 6 weeks in AMI patients. The mean serum PONase activity was lowest in AMI patients (23.26 U/ml) followed by stable CAD patients (102.0 U/ml) where as in controls was highest (179.8 U/ml). In patients with AMI, activity was significantly higher at 6 weeks as compared to that after acute event (49.39 %; p < 0.05). Sudden lowering of serum PONase activity in a population which already has lower activity may be one of the risk factors for development of AMI.

Effect of paraoxonase-1 polymorphism on clinical outcomes in patients treated with clopidogrel after an acute myocardial infarction

Paraoxonase-1 (PON1) Q192R polymorphism was recently suggested to determine per se clopidogrel response on major cardiovascular events (MACEs). We assessed the impact of PON1, CYP2C19, and ABCB1 polymorphisms on MACE in clopidogrel-treated acute myocardial infarction (AMI) patients (N = 2,210), including those undergoing percutaneous coronary intervention (PCI) (n = 1,538). PON1 polymorphism was not associated with increased risk of in-hospital death and MACEs at 1 year (adjusted hazard ratio (HR) 1.03, 95% confidence interval (CI) 0.66-1.61 and adjusted HR 0.77, 95% CI 0.42-1.41 for QQ versus RR in all and PCI patients, respectively). The presence of two CYP2C19 loss-of-function (LOF) alleles was associated with the risk of in-hospital death and MACEs at 1 year in the overall population (adjusted odds ratio (OR) 3.67, 95% CI 1.05-12.80 and adjusted HR 1.96, 95% CI 1.08-3.54) and in PCI patients (adjusted OR 6.87, 95% CI 2.52-18.72 and adjusted HR 3.06, 95% CI 1.47-6.41). Unlike CYP2C19 polymorphism, PON1 (Q192R) polymorphism is not a major pharmacogenetic contributor of clinical response to clopidogrel in AMI patients.

Are PON1 Q/R 192 and M/L 55 polymorphisms risk factors for diabetes complications in Turkish population?

OBJECTIVES

We investigated whether the human serum paraoxonase (PON1) Q/R 192 and M/L 55 polymorphisms are associated with the complications of the type 2 diabetes (T2D).

DESIGN AND METHODS

Study group was consisted of 50 healthy subjects and 100 type 2 diabetes mellitus (DM) patients. Following measuring of serum PON1 activity, isolation of DNA and genotyping analyses were performed.

RESULTS

PON1 activity of the patients with complications was significantly reduced by 23.5% compared to the group of diabetic patients and by 26.3% than the controls. According to multivariate analysis, we observed a three times significant effect of Q/R 192 polymorphism on the susceptibility to the occurrence of complications.

CONCLUSIONS

Protective effects of paraoxonase against peroxidation of LDL particles are important in T2D complications. Although both of the two polymorphisms are associated, 192 polymorphism seems to be stronger predictor of the risk of diabetic complications.

Association of the eNOS E298D polymorphism and the risk of myocardial infarction in the Greek population

Background

Nitric oxide (NO), produced by endothelial nitric oxide synthase (eNOS), plays a key role in the regulation of vascular tone. Endothelium-derived NO exerts vasoprotective effects by suppressing platelet aggregation, leukocyte adhesion and smooth muscle cell proliferation. The E298D polymorphic variant of eNOS has been associated with myocardial infarction (MI), but data relating to this variant are divergent in Greece. Accordingly, we examined a possible association between the E298D polymorphism of the eNOS gene and MI in a subgroup of the Greek population.

Methods

The study population consisted of 204 patients with a history of MI and 218 control subjects. All subjects were of Greek origin and were selected from the general population of the greater Athens area. Genotyping was performed with melting curve analysis (Lightcycler system) of polymerase chain reaction amplified products using hybridization probes.

Results

According to the univariate findings, the risk for MI in E298D TT was 2.06 (95%CI: 1.06-4.00, p = 0.032) versus GG+GT and 2.34 (95%CI: 1.17-4.68, p = 0.016) versus GG. The risk for the T allele was estimated at 1.42 (95%CI, 1.06-1.89, p = 0.022) as compared to G allele. Regarding the additive model, one allele increase was associated with 43% higher risk of MI (OR = 1.43, 95%CI: 1.07-1.93, p = 0.018) as compared to the baseline category of homozygous GG. The positive association of TT versus GG+GT with MI risk remained even after adjusting for the main study covariates. Moreover, strong evidence was found for an increased risk for MI among carriers of the TT genotype who were smokers, hypertensive and had a family history of CAD.

Conclusions

This study indicates that E298D polymorphism of the eNOS gene seems to be associated with MI occurrence in the Greek population. It is possible that TT genotype is closely linked to the etiology of MI even after adjusting for known MI risk factors.

The paraoxonase L55M and Q192R gene polymorphisms and myocardial infarction in a Tunisian population

OBJECTIVES

In the present study, we examined a possible association between the PON1 Q192R and L55M polymorphisms and myocardial infarction (MI) in a sample of the Tunisian population.

DESIGN AND METHODS

Three hundred and ten patients with MI and 375 controls were recruited. Paraoxonase gene polymorphisms at codon 192 and 55 were analyzed by PCR-RFLP.

RESULTS

Genotype distributions and allele frequencies of L55M were similar among the control and MI groups. For the Q192R polymorphism patients with MI had significantly higher frequency of the RR genotype compared to controls [17.1% vs. 10.9%; OR (95% CI), 1.93 (1.24-3.02); p=0.004]. The MI patient group showed a significantly higher frequency of the R allele compared to the controls [38% vs. 30%; χ(2)=10.74, p=0.001]. The association between the PON1 Q192R polymorphism and MI remained significant after adjustment for other well-established cardiovascular risk factors.

CONCLUSIONS

The present study showed a significant and independent association between the PON1 Q192R polymorphism (presence of R allele) and MI in the Tunisian population.

Is Polymorphism within eNOS Gene Associated With the Late Onset of Myocardial Infarction? A Pilot Study

Introduction

Nitric oxide (NO) produced by endothelial nitric oxide synthase (eNOS) is a potent vasodilator. Several polymorphisms in the eNOS gene have been described, some of them being linked with the increased risk of cardiovascular disease, coronary heart disease (CHD), and coronary spasm.

Methods and Results

We studied 3 polymorphisms within the gene of eNOS (-786T/C, G10T, and 894 G/T) in patients with their first myocardial infarction (MI) younger than 45 years and in healthy volunteers. We found the relation between the occurrence of eNOS 894G allele and the Gensini score, which describes the severity of CHD ( P = .020).

Conclusions

The fact that first clinical manifestation of MI occurred in G carriers when the atherosclerotic plaque was much more advanced than in T carriers may suggest that wild-type genotype provided a better compensatory mechanisms due to NO synthesis and/or release. The polymorphisms within eNOS gene G10T, 894G/T, and −786T/C were not associated with the increased risk of MI.

The endothelial nitric oxide synthase gene and risk of diabetic nephropathy and development of cardiovascular disease in type 1 diabetes

Nitric oxide (NO) is important in the maintenance of vascular tone and regulation of blood pressure. NO may also play a role in the development of both nephropathy and cardiovascular disease (CVD) in patients with diabetes. The susceptibility to nephropathy and CVD depends to some extent on genetic factors, therefore polymorphisms in the gene coding for endothelial NO-synthase, NOS3, can affect the risk of developing these diseases. Type 1 diabetes patients attending the Steno Diabetes Center, Denmark, between 1993 and 2001 were enrolled in this study. A total of 458 cases with diabetic nephropathy (albumin excretion >300 mg/24h) and 319 controls with persistent normoalbuminuria (<30 mg/24h), despite > or =20 years of diabetes duration at follow-up were identified. Patients were followed until death or end of the study. Associations between seven NOS3-gene polymorphisms and nephropathy, progression of nephropathy and CVD were studied. There was significant association between the rs743507 TT-genotype and diabetic nephropathy. When including age at diabetes onset, diabetes duration at follow-up, baseline Hb(A1c), sex and ever smoking in the analysis the OR was 1.43 (95% CI=1.03-2.00), P=0.035. In analyses of CVD development using Cox-regression the rs1799983 GG-genotype was a significant protective factor in normoalbuminuric patients, HR=0.32 (0.12-0.82), P=0.018, but not in patients with macroalbuminuria (covariates were; age at follow-up, baseline Hb(A1c), baseline systolic blood pressure, baseline cholesterol, sex and ever smoking). Our conclusion is that the NOS3-gene may be involved in the development of diabetic nephropathy in patients with type 1 diabetes and can be predictive of CVD during follow-up.

Anti-(apolipoprotein A-1) IgGs are associated with high levels of oxidized low-density lipoprotein in acute coronary syndrome

ApoA-1 (apolipoprotein A-1) is the main component of HDL (high-density lipoprotein) and stabilizes PON-1 (paraoxonase-1), which prevents lipid peroxidation and oxLDL (oxidized low-density lipoprotein) formation. Autoantibodies against apoA-1 [anti-(apoA-1) IgG] have been found in antiphospholipid syndrome and systemic lupus erythematosous, two diseases with an increased risk of thrombotic events, as well as in ACS (acute coronary syndrome). OxLDL levels are also elevated in these diseases. Whether anti-(apoA-1) IgGs exist in other prothrombotic conditions, such as APE (acute pulmonary embolism) and stroke, has not been studied and their potential association with oxLDL and PON-1 activity is not known. In the present study, we determined prospectively the prevalence of anti-(apoA-1) IgG in patients with ACS (n=127), APE (n=58) and stroke (n=34), and, when present, we tested their association with oxLDL levels. The prevalance of anti-(apoA-1) IgG was 11% in the ACS group, 2% in the control group and 0% in the APE and stroke groups. The ACS group had significantly higher median anti-(apoA-1) IgG titres than the other groups of patients. Patients with ACS positive for anti-(apoA-1) IgG had significantly higher median oxLDL values than those who tested negative (226.5 compared with 47.7 units/l; P<0.00001) and controls. The Spearman ranked test revealed a significant correlation between anti-(apoA-1) IgG titres and serum oxLDL levels (r=0.28, P<0.05). No association was found between PON-1 activity and oxLDL or anti-(apoA-1) IgG levels. In conclusion, anti-(apoA-1) IgG levels are positive in ACS, but not in stroke or APE. In ACS, their presence is associated with higher levels of oxLDL and is directly proportional to the serum concentration of oxLDL. These results emphasize the role of humoral autoimmunity as a mediator of inflammation and coronary atherogenesis.

Effect of rosuvastatin versus atorvastatin treatment on paraoxonase-1 activity in men with established cardiovascular disease and a low HDL-cholesterol

OBJECTIVE

Paraoxonase-1 (PON-1) is a high-density lipoprotein (HDL) associated enzyme involved in the protective mechanisms of HDL. Our aim was to compare the effect of treatment with rosuvastatin and atorvastatin on serum PON-1 activity.

METHODS

We performed a prespecified prospective study in 68 patients, part of a larger, multicentre randomized study--RADAR (Rosuvastatin and Atorvastatin in different Dosages And Reverse cholesterol transport). Patients aged 40-80 years, all men, with established cardiovascular disease and high-density lipoprotein cholesterol (HDL-C) < 1.0 mmol/L (< 40 mg/dL) entered a 6-week dietary run-in period before receiving treatment with rosuvastatin 10 mg or atorvastatin 20 mg daily for 6-weeks. Doses were increased after 6 weeks to rosuvastatin 20 mg or atorvastatin 40 mg and after 12 weeks to rosuvastatin 40 mg or atorvastatin 80 mg daily. Serum PON-1 activity and lipid profile were determined at baseline, 6 and 18 weeks.

RESULTS

After 18 weeks, the rosuvastatin arm showed a significant increase of PON-1 activity (6.39 U/L, p = 0.02) whereas this was not observed in the atorvastatin arm (1.84 U/L, p = 0.77). The difference between groups did not reach significance (p = 0.11). Both rosuvastatin and atorvastatin resulted in significant (p = 0.0001) and similar increases in HDL-C after 6 weeks [0.06 mmol/L (2.32 mg/dL) vs. 0.05 mmol/L (1.93 mg/dL)] and after 18 weeks [0.10 mmol/L (3.87 mg/dL) vs. 0.10 mmol/L (3.87 mg/dL)].

CONCLUSIONS

Rosuvastatin treatment resulted in a significant increment of serum PON-1 activity with increasing dose while this was not observed with atorvastatin.