Impact of Genetic Variations of theCYP1A1, GSTT1, andGSTM1Genes on the Risk of Coronary Artery Disease

An updated analysis on the association of GSTM1 polymorphism and smoking exposure with the increased risk of coronary heart disease

Objective

To undertake a meta-analysis to investigate if there is an association between the glutathione S-transferase mu 1 (GSTM1) gene polymorphism, coronary artery disease (CAD) susceptibility and smoking.

Methods

Electronic databases, including PubMed®, Web of Science and Embase®, were searched for relevant case–control studies. Data were extracted and the odds ratio (OR) was calculated and appropriate statistical methods were used for the meta-analysis.

Results

The analysis included eight studies with a total of 1880 cases with CAD and 1758 control subjects. The results of this meta-analysis demonstrated that there is no association between the GSTM1 null and CAD (OR 1.24, 95% confidence interval [CI] 1.00, 1.55). An increased risk of CAD was observed in the smoking population with the GSTM1 null genotype (OR 1.48, 95% CI 1.02, 2.15). Subgroup analyses of geographical region, genotyping method and publication language category demonstrated potential relationships among gene polymorphism, smoking and CAD.

Conclusions

Based on the current literature, the GSTM1 null genotype was associated to CAD in the smoking population. The interaction between smoking and GSTM1 polymorphism may contribute to the susceptibility of CAD.

Contribution of Glutathione-S-Transferases Polymorphism and Risk of Coronary Artery Diseases: A Meta-Analysis

BACKGROUND

Oxidative stress is one of the risk components in the development of coronary artery diseases (CAD) and polymorphism in major antioxidant genes like Glutathione-S-Transferases (GST) has been associated with the increased CAD susceptibility and severity.

OBJECTIVE

To get a precise evaluation and to update the association, a meta-analysis on GST (GSTM1, GSTT1 and GSTP1) polymorphism with CAD was performed. Moreover, the combined effect of GSTM1/GSTT1 null genotypes on CAD risk which is not yet studied so far but it has the highest risk of developing diseases.

MATERIALS AND METHOD

PubMed, Embase and Web of Science were systematically searched for eligible studies. Case-control studies with genotypic frequency, provide data to calculate odds ratio (OR) and in English language were selected. OR with 95% C.I was calculated and random effect model was used. NOS scale was used to asses the qulity of the included studies.

RESULTS

Meta-analysis indicated that the GSTM1 null genotype and GSTP1 (Ile105Val) polymorphism is significantly associated with CAD risk with a pooled OR-1.38, p=0.01 for GSTM1 and OR-1.19, p=0.04 for GSTP1. Dual null genotype of GSTM1-GSTT1 has highest risk for CAD development (OR-1.59, p=0.003) and there is no significant association for GSTT1 null genotype with CAD. In the subgroup analysis, GSTM1 showed the increased risk for Asians (OR-1.68, p=<0.01) and smokers (OR-1.98, p=<0.01). Publication bias was not observed.

CONCLUSION

The findings suggests that the GSTM1/GSTP1 polymorphism can be a predictive factor for CAD risk and a larger sample size is required further to confirm the association.

The association study between CYP20A1, CYP4F2, CYP2D6 gene polymorphisms and coronary heart disease risk in the Han population in southern China

BACKGROUND

Coronary heart disease (CHD) is a disease that seriously harms human health. Genetic factors seriously affect the CHD susceptibility. The CYP20A1, CYP4F2 and CYP2D6 are important drug metabolism enzymes in the human body.

OBJECTIVE

We aimed to explore the association between CYP20A1, CYP4F2, CYP2D6 single nucleotide polymorphisms (SNPs) and CHD risk in the Chinese Southern Han population.

METHODS

Based on the 'case-control' experimental design (505 cases and 508 controls), we conducted an association study between 5 candidate SNPs selected from CYP20A1 (rs2043449), CYP4F2 (rs2108622, rs3093106, rs309310), CYP2D6 (rs1065852) and CHD risk. Logistic regression was used to analyze the CHD susceptibility under different genetic models. Multi-factor dimensionality reduction (MDR) was used to analyze the interaction of 'SNP-SNP' in CHD risk.

RESULTS

Our results showed that under multiple genetic models, CYP2D6 rs1065852 significantly increased the CHD risk in these participants who are ≤ 60 years old (OR 1.40, CI 1.07-1.82, p = 0.013), smokers (OR 1.40, CI 1.02-1.93, p = 0.039), or have family history (OR 1.24, CI 1.02-1.51, p = 0.035). CYP4F2 SNPs rs2108622 (OR 0.63, CI 0.43-0.93, p = 0.020), rs3093106 (OR 0.52, CI 0.29-0.92, p = 0.023), and rs309310 (OR 0.55, CI 0.31-0.96, p = 0.033) were potentially associated with the course of CHD patients.

CONCLUSION

Our study found that CY2D6 rs1065852 has an outstanding and significant association with increased CHD risk. Our study provided data supplements for CHD genetic susceptibility loci, and also provided a new and valuable reference for CHD drug treatment.

The association of glutathione S-transferase T1 and M1 deletions with myocardial infarction

Glutathione S-transferases (GSTs) are the family of enzymes involved in the second line of defense against oxidative stress (OS). The lack of GSTT1/GSTM1 enzyme quantity or activity, due to the presence of homozygous deletion compromises antioxidative defense resulting in OS. OS is the critical mechanism in the pathophysiology of atherosclerosis, coronary artery disease, and myocardial infarction (MI). The increase in reactive oxygen species together with the process of apoptosis plays a role in left ventricular remodeling (LVR) after MI. The associations of GSTT1 and GSTM1 gene polymorphisms with the risk of MI are inconsistent. The aim was to analyze the association of GSTT1/GSTM1 null genotypes with first MI and LVR 8 months after the MI. The study involved 330 controls and 438 consecutive patients with symptoms and signs of first MI. The subgroup of 150 MI patients was prospectively followed up for 6 months. Evidence of maladaptive LVR was obtained by 2D Doppler echocardiography 3-5 days and 6 months after the MI. A multiplex polymerase chain reaction was used to detect the deletion in GSTT1 and GSTM1 genes. GSTM1 null genotype was significantly and independently associated with first MI (adjusted OR = 1.45 95% CI 1.03-2.03, p = 0.03). Association of double null genotypes with maladaptive LVR in patients 6 months after the first MI was no longer significant after adjustment for factors that differed significantly between patients with and without maladaptive LVR. This study demonstrated the association of GSTM1 null genotypes with the risk of MI in the Serbian population.

An updated meta-analysis showed smoking modify the association of GSTM1 null genotype on the risk of coronary heart disease

Background Oxidative stress is considered to be involved in the pathogenesis of coronary heart disease (CHD). Glutathione-S-transferase (GST) enzymes play important roles in antioxidant defenses and may influence CHD risk. The present meta-analysis was performed to investigate the link between glutathione S-transferase M1 (GSTM1) null genotype and CHD and to get a precise evaluation of interaction between GSTM1 null genotype and smoking by the case-only design.

Methods PubMed and EMBASE databases were searched through 15 December 2020 to retrieve articles. Odds ratios (ORs) were pooled using either fixed-effects or random-effects models.

Results Thirty-seven studies showed that GSTM1 null genotype was associated with risk of CHD in total population, Caucasians and Asians (for total population, OR = 1.38, 95% confidence interval (CI): 1.15, 1.65; for Caucasians, OR = 1.34, 95% CI: 1.04, 1.72; for Asians, OR = 1.40, 95% CI: 1.11, 1.77). After adjustment for heterogeneity, these relationships were still significant. After adjustment for heterogeneity, case-only analysis of 11 studies showed a positive multiplicative interaction between GSTM1 null genotype and smoking (ever smoking vs. never smoking) (OR = 1.27, 95% CI: 1.08, 1.50; I² = 0%, P=0.553).

Conclusions The overall results indicated that GSTM1 null genotype was associated with a higher risk of CHD, and the association may be affected by smoking status. This is the first meta-analysis to prove a positive effect of the interaction between GSTM1 null genotype and smoking status on the risk of CHD. Well-designed studies are needed to investigate the possible gene–gene or gene–environment interactions.

Aryl hydrocarbon receptor pathway: Role, regulation and intervention in atherosclerosis therapy (Review)

The aryl hydrocarbon receptor (AhR) is a ligand‑activated transcription factor originally isolated and characterized as the dioxin or xenobiotic receptor. With the discovery of endogenous ligands and studies of AhR knockout mice, AhR has been found to serve an important role in several biological processes, including immune responses and developmental and pathological regulation. In particular, it has been considered as a new major player in cardiovascular diseases. Recent studies have revealed that the development of atherosclerosis is closely associated with AhR function. However, the roles of the AhR in the pathological development of atherosclerosis and atherosclerosis‑associated diseases remain unclear. The current review presents the molecular mechanisms involved in the regulation of AhR expression during inflammation, oxidative stress and lipid deposition. Additionally, the role of the AhR in atherosclerosis and atherosclerosis‑associated diseases is reviewed.

Gene-gene interaction between PPARG and CYP1A1 gene on coronary artery disease in the Chinese Han Population

AIMS

To observe the influence of the peroxisome proliferator-activator receptor-G (PPAR-G) gene and cytochrome P4501A1 (CYP1A1) single-nucleotide polymorphisms (SNPs), and interactions among several SNPs on coronary artery disease (CAD) risk.

METHODS

A total of 1106 participants (including 583 males and 523 females) including 550 CAD patients and 556 control subjects were recruited in this study, and the mean age for these participants was 55.5 ± 11.8 years old. Logistic regression was used to observe association of SNP within PPARG and CYP1A1 with CAD risk and GMDR model was used to screen the best interaction combinations.

RESULTS

CAD susceptibility was higher in those with homozygous mutant of rs10865710, rs1805192 and rs4646903 than those with wild-type homozygotes, OR (95%CI) were 1.47 (1.15-1.92), 1.69 (1.27-2.09) and 1.72 (1.35-2.32), respectively. We also found a significant two-locus model involving rs1805192 and rs4646903 (p = 0.0107), and the cross-validation consistency of this locus model was 10 of 10, the testing accuracy of this model is 62.17%. Logistic regression shown that CAD risk was the highest in those with rs1805192- Pro/Ala or Ala/Ala and rs4646903- AG+GG genotype, and was lowest in those with rs1805192- Pro/ Pro and rs4646903- AA genotype, OR(95%CI) = 3.56 (1.91-5.42).

CONCLUSIONS

Polymorphism in rs10865710, rs1805192 and rs4646903 and interaction between rs1805192 and rs4646903 were related with increased CAD susceptibility.

Genetic polymorphisms of the CYP1A1, GSTM1, and GSTT1 enzymes and their influence on cardiovascular risk and lipid profile in people who live near a natural gas plant

The aim of this cross-sectional study was to see whether genetic polymorphisms of the enzymes CYP1A1, GSTM1, and GSTT1 are associated with higher risk of coronary artery disease (CAD) and whether they affect lipid profile in 252 subjects living near a natural gas plant, who are likely to be exposed to polycyclic aromatic hydrocarbons (PAHs). Fasting serum concentrations of biochemical parameters were determined with standard methods. Genetic polymorphisms of CYP 1A1 rs4646903, rs1048943, rs4986883, and rs1799814 were genotyped with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFPL), while GSTM1 and GSTT1 deletions were detected with multiplex PCR. Cardiovascular risk was assessed with Framingham risk score, and the subjects divided in two groups: >10% risk and ≤10% risk. The two groups did not differ in the genotype frequencies. MANCOVA analysis, which included lipid parameters, glucose, and BMI with sex, age, hypertension and smoking status as covariates, showed a significant difference between the GSTT1*0 and GSTT1*1 allele carriers (p=0.001). UNIANCOVA with same covariates showed that total cholesterol and triglyceride levels were significantly higher in GSTT1*1 allele carriers than in GSTT1*0 carriers (p<0.001 and p=0.006, respectively). Our findings suggest that CYP1A1, GSTM1, and GSTT1 polymorphisms are not associated with the higher risk of CAD, but that GSTT1 affects lipid profile.

Impact of interaction between CYP1A1 genetic polymorphisms and smoking on coronary artery disease in the Han of China

AIMS

To investigate the association of CYP1A1 genotype and additional gene-smoking interaction with coronary artery disease (CAD) risk based on a Chinese case-control study.

METHODS

A total of 1862 participants (1134 men, 728 women) were selected, including 620 CAD patients and 1242 normal controls. Logistic regression was performed to investigate association of CYP1A1 genotype, gene-gene, and gene-smoking interaction with CAD. Generalized multifactor dimensionality reduction (GMDR) was used to screen the best gene-gene and gene-smoking interaction combination, cross-validation consistency, the testing balanced accuracy, and the sign test, to assess if each selected interaction was calculated.

RESULTS

The carriers of homozygous mutant of rs4886605 polymorphism and heterozygous of rs4646903 are associated with increased CAD risk than those with wild-type homozygotes; OR (95% CI) was 1.98 (1.53-2.61) and 1.58 (1.24-1.96), respectively. The carriers of homozygous mutant of rs1048943 polymorphism is associated with decreased CAD risk than those with wild-type homozygotes, OR (95% CI) = 0.75 (0.60-0.93). GMDR model indicated a potential gene-gene interaction between rs4886605 and rs4646903 and a potential gene-smoking interaction between rs4886605 and smoking. Participants with rs4886605-CT or TT and rs4646903-TC or CC genotype have the highest CAD risk, compared to participants with rs4886605-CC and rs4646903-TT genotype; OR (95% CI) was 2.72 (2.03-3.61). In addition, we also found that smokers with rs4886605-CT or TT genotype have the highest CAD risk, compared to nonsmokers with rs4886605-CC genotype; OR (95% CI) was 3.07 (2.23-3.96).

CONCLUSIONS

rs4886605 and rs4646903 are associated with increased CAD risk, but rs1048943 is associated with decreased CAD risk; we also found gene-gene interaction between rs4886605 and rs4646903 and gene-environment interaction between rs4886605 and smoking.

Effects of antioxidant system on coronary artery lesions in patients with abnormal glucose metabolism

OBJECTIVE

To evaluate the effects of catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH) system on the range and severity of coronary artery lesions in patients with abnormal glucose metabolism.

METHODS

This study included 766 patients with abnormal glucose metabolism. Levels of fasting blood lipids, blood glucose, CAT, SOD, GSH, glutathione reductase (GR), and glutathione peroxidase (GSH-Px) were measured in all the patients. Coronarography was performed, and the degree of the lesions in each coronary artery was quantitatively analyzed using the Gensini scoring system.

RESULTS

In patients with impaired glucose regulation and diabetes, the number of coronary artery branches with stenosis and the Gensini scores were inversely correlated with the plasma levels of CAT, SOD, GSH, GH, and GSH-Px (P < 0.001). Patients were grouped according to the Gensini scores. As the scores increased, the levels of CAT, SOD, GSH, GSH-Px, and GR gradually decreased. Logistic gradual regression analysis showed that GSH-Px and CAT were independent risk factors associated with the coronary artery lesions in three or more branches.

CONCLUSIONS

Decreased plasma levels of CAT, SOD, GSH, GR, and GSH-Px were inversely correlated, at least to some extent, with the extent of coronary artery lesions. Particularly, GSH-Px and CAT were independent risk factors associated with coronary artery lesions involving three or more branches. This suggests that long-term hyperglycemia leads to enhancement of oxidative stress.

Glutathione S-Transferase T1 (GSTT1) Null Polymorphism, Smoking, and Their Interaction in Coronary Heart Disease: A Comprehensive Meta-Analysis

BACKGROUND

The association between glutathione S-transferase T1 (GSTT1) null polymorphism and coronary heart disease (CHD) is inconsistent among studies, and data on the GSTT1 null genotype-smoking interplay in CHD is lacking. We conducted this meta-analysis to investigate the relationship between GSTT1 null polymorphism and CHD and to assess the potential interaction between GSTT1 null genotype and smoking.

METHODS

PubMed and EMBASE databases were searched up to 27 January 2016 using the appropriate terms. Odds ratios were pooled using either fixed-effects or random-effects models.

RESULTS

Twenty-nine articles including 31 studies with 15,004 cases and 35,597 controls were eligible. The random-effects model showed that the GSTT1 null genotype was associated with increased CHD risk (OR=1.213, 95%CI: 1.004-1.467; I²=90.4%). After excluding 10 studies detected by Galbraith plot, the fixed effects summary estimate also showed an increased risk of CHD (OR=1.14, 95% CI: 1.06-1.22; I²=27.7%). A case-only analysis including eight studies showed a statistically significant positive interaction between GSTT1 null polymorphism and smoking status on CHD (OR=1.34, 95% CI: 1.09-1.64; I²=0%). Sensitivity analyses further supported the associations. No publication bias was observed.

CONCLUSIONS

This meta-analysis suggests that GSTT1 null polymorphism is associated with the risk of CHD. To our knowledge, this is the first meta-analysis to prove a positive effect of the interaction between GSTT1 null genotype and smoking status on the risk of CHD. Future studies with detailed individual information are needed to confirm our findings.

The role of oxidative DNA damage and GSTM1, GSTT1, and hOGG1 gene polymorphisms in coronary artery disease risk

Objective:

Atherosclerotic coronary artery disease (CAD) appears to be a multifactorial process caused by the interaction of environmental risk factors with multiple predisposing genes. Therefore, in this study we aimed to determine the role of oxidative DNA damage and some variations in glutathione S-transferase (GSTM1 and GSTT1) and DNA repair (hOGG1) genes in CAD risk.

Methods:

A case-control study was conducted on 59 individuals who had undergone coronary angiographic evaluation. Of these, 29 were patients diagnosed with CAD (mean age =61.5±10.3) and 30 were controls examined for reasons other than suspected CAD and who had angiographically documented normal coronary arteries (mean age =60.4±11.6). Basal DNA damage as well as pyrimidine and purine base damage were evaluated in peripheral blood lymphocytes using the modified comet assay. Polymerase chain reaction-restriction length polymorphism (PCR-RFLP)-based assay was used for genotyping.

Results:

Basal DNA damage levels in patients [9.16 (3.26)] were significantly higher than those in controls [7.59 (3.23); p=0.017], and basal DNA and pyrimidine base damage levels were significantly correlated with disease severity based on Gensini scoring (r=0.352, p=0.006; r=0.318, p=0.014, respectively). However, no significant differences were observed in terms of oxidized DNA bases between patients and controls. The frequencies of studied genotypes (GSTM1, GSTT1, and hOGG1) were similar between groups.

Conclusion:

The results of this study pointed out the role of DNA damage in CAD and its severity. However, GSTM1, GSTT1, and hOGG1 gene polymorphisms seemed to have no effect on individual susceptibility for disease progression. (Anatol J Cardiol 2016; 16: 931-8)

Association of glutathione S-transferase T1 and M1 gene polymorphisms with ischemic stroke risk in the Chinese Han population

Atherosclerosis plays an important role in ischemic stroke, and oxidative stress participates in the entire process of atherosclerosis. Glutathione S-transferase (GST) acting with other antioxidant enzymes can eliminate reactive oxygen species and protect cells against oxidative damage. To assess the association of glutathione S-transferase (GSTT1 and GSTM1) gene polymorphisms with ischemic stroke in the Chinese Han population, the present study selected 315 patients with ischemic stroke and 210 healthy controls for comparison. GSTT1 and GSTM1 genotypes were determined using polymerase chain reactions, electrophoresis and imaging analysis. No obvious evidence of GSTT1-null, GSTM1-null and GSTT1/GSTM1-double null genotype distribution differences was found between case and control groups or between genders. Subgroup analysis showed that the risk of stroke was increased when hypertension was accompanied by GSTT1-null (odds ratio (OR) = 2.996, P < 0.001) and GSTM1-null (OR = 3.680, P < 0.001) genotypes; diabetes mellitus was accompanied by GSTT1-null (OR = 1.860, P = 0.031) and GSTM1-null (OR = 2.444, P = 0.002) genotypes, and smokers showed a GSTT1-null genotype (OR = 2.276, P = 0.003). GSTT1- and GSTM1-null genotypes may interact synergistically with hypertension, diabetes mellitus and smoking to increase the incidence risk of ischemic stroke.

Association between GSTM1 null genotype and coronary artery disease risk: a meta-analysis

Background

We conducted a meta-analysis to assess the association between polymorphisms of GSTM1 null genotype and coronary artery disease (CAD) risk.

Material/Methods

Published literature from PubMed, EMBASE, and China National Knowledge Infrastructure (CNKI) were retrieved before March 2014. All studies reporting adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of CAD risk were included.

Results

A total of 13 case-control studies, including 5453 cases and 5068 controls, were collected. There was a significant association between GSTM1 null genotype and CAD risk (adjusted OR=1.26; 95% CI, 1.11–1.43; I²=3%). When stratified by ethnicity, a significantly elevated risk was observed in whites. In the subgroup analysis according to disease type, a significantly increased myocardial infarction (MI) risk was observed. Subgroup analysis of smoking status showed an increased CAD risk in smokers.

Conclusions

Our results indicate that GSTM1 null genotype is associated with an increased CAD risk.

Glutathione S-transferase M1 polymorphism and coronary heart disease susceptibility: a meta-analysis involving 47,596 subjects

BACKGROUND

Many studies have investigated the association between glutathione S-transferase M1 (GSTM1) null genotype and the risk of coronary heart disease (CHD). However, the effect of the GSTM1 null genotype on CHD is still unclear because of apparent inconsistencies among those studies. A meta-analysis was performed to characterise the relationship more accurately.

METHODS

Pubmed, Embase, and Web of Science were searched. We estimated the summary odds ratio (OR) with a 95% confidence interval (95% CI) to assess the association.

RESULTS

Up to 26 case-control studies with 13,929 CHD cases and 33,667 control cases were included into this meta-analysis. Meta-analysis of the 26 studies showed that GSTM1 null genotype was associated with the risk of CHD (random effects OR=1.35, 95% CI 1.00 to 1.83). After adjustment for heterogeneity, meta-analysis showed that GSTM1 null genotype was not associated with increased risk of CHD in the total population (fixed effects OR=1.01, 95% CI 0.95 to 1.07). In the subgroup analysis by ethnicity, increased risks were not found for either Caucasians (OR=1.36, 95% CI=0.96-1.92) or Asians (OR=1.28, 95% CI=0.91-1.80). When stratified by smoking status, in the subgroup of smokers, GSTM1 null genotype was significantly associated with increased CHD risk (random effects OR=1.64, 95% CI 1.02 to 2.64). No evidence of publication bias was observed.

CONCLUSION

In conclusion, this meta-analysis suggested that there is overall lack of association between GSTM1 genotypes and CHD risk, however, GSTM1 null genotype when combining with smoking history may contribute to CHD susceptibility.

Association between 3801T>C polymorphism of CYP1A1 and idiopathic male infertility risk: a systematic review and meta-analysis

BACKGROUND

Epidemiological studies have evaluated the association between 3801T>C polymorphism of CYP1A1 gene and the risk for idiopathic male infertility, but the results are inconclusive. We aimed to derive a more precise estimation of the relationship by conducting a meta-analysis of case-control studies.

METHODS

This study conformed to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, Embase and CNKI databases were searched through November 2013 to identify relevant studies. Pooled odds ratios with 95% confidence intervals were used to assess the strength of the association between CYP1A1 3801T>C polymorphism and idiopathic male infertility risk. Q-test was performed to evaluate between-study heterogeneity and publication bias was appraised using funnel plots. Sensitivity analyses were conducted to evaluate the robustness of meta-analysis findings.

RESULTS

Six studies involving 1,060 cases and 1,225 controls were included in this meta-analysis. Overall, significant associations between 3801T>C polymorphism and idiopathic male infertility risk were observed in allelic comparison (OR = 1.36, 95% CI: 1.01-1.83), homozygous model (OR = 2.18, 95% CI: 1.15-4.12), and recessive model (OR = 1.86, 95% CI: 1.09-3.20), with robust findings according to sensitivity analyses. However, subgroup analyses did not further identify the susceptibility to idiopathic male infertility in all comparisons. Funnel plot inspections did not reveal evidence of publication bias.

CONCLUSIONS

The current meta-analysis provides evidence of a significant association between CYP1A1 3801T>C polymorphism and idiopathic male infertility risk. Considering the limitation inherited from the eligible studies, further confirmation in large-scale and well-designed studies is needed.

Associations of GSTM1*0 and GSTA1*A genotypes with the risk of cardiovascular death among hemodialyses patients

Background

The presence of glutathione transferase (GST) M1 null genotype (GSTM1-null) in end-stage renal disease (ESRD) patients is associated with lower overall survival rate in comparison to those with GSTM1-active variants. We examined association between GSTM1 and GSTT1 deletion polymorphisms as well as SNPs in GSTA1/rs3957357 and GSTP1/rs1695 genes with overall and cause-specific cardiovascular mortality in ESRD patients.

Methods

Total of 199 patients undergoing hemodialysis were included in the study. Median value of time elapsed from dialysis initiation until the death, or the end of follow-up was 8 ± 5 years. The effect of GSTM1, GSTT1, GSTP1 and GSTA1 gene polymorphisms on predicting overall and specific cardiovascular outcomes (myocardial infarction, MI or stroke) was analyzed using Cox regression model, and differences in survival were determined by Kaplan-Meier.

Results

GSTM1-null genotype in ESRD patients was found to be independent predictor of overall and cardiovascular mortality. However, after false discovery rate and Bonferroni corrections this effect was lost. The borderline effect modification by wild-type GSTA1*A/*A genotype on associations between GSTM1-null and analyzed outcomes was found only for death from stroke. Homozygous carriers of combined GSTM1*0/GSTA1*A genotype exhibited significantly shorter time to death of stroke or MI in comparison with carriers of either GSTM1-active or at least one GSTA1*B gene variant. The best survival rate regarding cardiovascular outcome was found for ESRD patients with combined GSTM1-active and mutant GSTA1*B/*B genotype.

Conclusions

Combined GSTM1*0/GSTA1*A genotypes might be considered as genetic markers for cardiovascular death risk in ESRD patients, which may permit targeting of preventive and early intervention.

Polymorphisms of genes involved in polycyclic aromatic hydrocarbons' biotransformation and atherosclerosis

Polycyclic aromatic hydrocarbons (PAHs) are among the most prevalent environmental pollutants and result from the incomplete combustion of hydrocarbons (coal and gasoline, fossil fuel combustion, byproducts of industrial processing, natural emission, cigarette smoking, etc.). The first phase of xenobiotic biotransformation in the PAH metabolism includes activities of cytochrome P450 from the CYP1 family and microsomal epoxide hydrolase. The products of this biotransformation are reactive oxygen species that are transformed in the second phase through the formation of conjugates with glutathione, glucuronate or sulphates. PAH exposure may lead to PAH-DNA adduct formation or induce an inflammatory atherosclerotic plaque phenotype. Several genetic polymorphisms of genes encoded for enzymes involved in PAH biotransformation have been proven to lead to the development of diseases. Enzyme CYP P450 1A1, which is encoded by the CYP1A1 gene, is vital in the monooxygenation of lipofilic substrates, while GSTM1 and GSTT1 are the most abundant isophorms that conjugate and neutralize oxygen products. Some single nucleotide polymorphisms of the CYP1A1 gene as well as the deletion polymorphisms of GSTT1 and GSTM1 may alter the final specific cellular inflammatory respond. Occupational exposure or conditions from the living environment can contribute to the production of PAH metabolites with adverse effects on human health. The aim of this study was to obtain data on biotransformation and atherosclerosis, as well as data on the gene polymorphisms involved in biotransformation, in order to better study gene expression and further elucidate the interaction between genes and the environment.

Interactive effects of smoking and glutathione S-transferase polymorphisms on the development of non-alcoholic fatty liver disease

Glutathione S-transferases (GSTs) protect cells against exogenous and endogenous oxidative stress. GST polymorphisms are associated with the development of cardiovascular disease (CVD) and diabetes mellitus (DM), especially in current-smokers. Non-alcoholic fatty liver disease (NAFLD) is a predictor of future CVD or DM, because oxidative stress contributes to their pathogenesis. This study investigated whether the combination of smoking status and GST genotypes could affect the risk for NAFLD. A cross-sectional analysis was conducted among 713 Japanese participants (458 males and 255 females) during a health screening program. The GSTM1 null, GSTT1 null, GSTP1 A/B or B/B and GSTA1 A/B or B/B genotypes were determined and deemed to be high-risk genotypes. The prevalence of NAFLD was 18.7%. Among never-smokers, carriers of one, and those of two or more high-risk GSTM1, GSTP1 or GSTA1 genotypes were at a higher risk for NAFLD than those who were not carriers [odds ratio (95% confidence interval): 2.6 (1.1-5.9) and 3.3 (1.3-8.1), respectively], and the risk was further increased among current-smokers [4.6 (1.6-13.0) and 5.4 (1.2-23.7), respectively]. This is the first report to show that the combination of current-smoking and harboring high-risk GSTM1, GSTP1 and/or GSTA1 genotypes is interactively associated with the risk of NAFLD.

Glutathione S-transferase M1 and T1 genotypes and myocardial infarction

Myocardial infarction (MI), which is the most important manifestation of coronary artery disease, is the leading cause of morbidity and mortality in the world. Glutathione S transferases (GSTs) are enzymes responsible for the metabolism of numerous xenobiotics and are known to be polymorphic in humans. We investigated the association between the GSTM1 and GSTT1 gene polymorphisms and MI. The study consists of 296 healthy controls and 324 consecutive patients who had undergone coronary angiography for suspicion of coronary artery disease and with a past history of myocardial infarction. DNA was extracted from whole blood of patient and control. GSTM1 and GSTT1 gene polymorphisms were examined using multiplex PCR. We found that the null GSTM1 was associated with protective effect on MI, although this increase was not significant for GSTM1 (p < 0.054). However, GSTT1 genotype was associated with an increase in the risk of developing MI. In addition to after adjusting other all coronary risk factors, the interactive effect of GSTT1 null genotype remained statistically significant (p < 0.001) for MI disease but GSTM1 null genotype was not statistically significant. Patients, who smoke having the null genotypes of GSTM1, were at a higher risk for developing MI (p < 0.001, OR = 0.41, 95 % CI = 0.240-0.207). There was an effect of interaction of GSTM1 null genotype and smoking on MI development between patient and control groups (p < 0.001). Our results showed that individuals with the null genotypes for GSTM1 had protective effect, while GSTT1 was at a higher risk for MI disease. In addition, there was additional effects of smoking when smoking and non-smoking groups were compared.

Lack of association between CYP1A1 T6235C polymorphism and coronary artery disease: evidence from a meta-analysis

A number of studies have evaluated the correlation between the cytochrome P450 1A1 (CYP1A1) T6235C polymorphism and coronary artery disease (CAD) risk, however, at present the results remain inconclusive. To provide a more robust investigation of this correlation, a meta-analysis was performed. In the present study, a systematic search of PubMed, Embase and CBM databases for studies published prior to June 6, 2012 was performed. The correlation between the CYP1A1 T6235C polymorphism and CAD risk was assessed by calculating pooled odds ratios (ORs) and 95% confidence intervals (95% CIs). Seven studies with a total of 2,903 cases and 2,304 controls were included in the meta-analysis. Overall, the CYP1A1 T6235C polymorphism was not correlated with CAD risk (C vs. T: OR=1.03; 95% CI, 0.87-1.22; P=0.728; CC vs. TT: OR=1.04; 95% CI, 0.84‑1.19; P=0.699; CC+TC vs. TT: OR=1.04; 95% CI, 0.93-1.18; P=0.478; CC vs. TC+TT: OR=1.04; 95% CI, 0.85‑1.28; P=0.704). A meta-analysis of five high-quality studies demonstrated that the CYP1A1 T6235C polymorphism is not correlated with risk of CAD in 4 genetic models. Ethnic subgroup analyses identified no significant correlation in Caucasian, Asian and African populations. The present meta-analysis study indicates that the CYP1A1 T6235C polymorphism is not correlated with CAD risk. Additional studies with a larger sample size and consistent design must be performed to confirm the present hypothesis.