GSTM1, GSTT1, GSTP1, and GSTA1 genetic variants are not associated with coronary artery disease in Taiwan

The importance of polymorphisms in the genes encoding glutathione S-transferase isoenzymes in development of selected cancers and cardiovascular diseases

Glutathione S-transferases are a family of enzymes, whose main role is to detoxify cells from many exogenous factors, such as xenobiotics or carcinogens. It has also been proven that changes in the genes encoding these enzymes may affect the incidence of selected cancers and cardiovascular diseases. The aim of this study was to review the most important reports related to the role of glutathione S-transferases in the pathophysiology of two of the most common diseases in modern society - cancers and cardiovascular diseases. It was shown that polymorphisms in the genes encoding glutathione S-transferases are associated with the development of these diseases. However, depending on the ethnic group, the researchers obtained divergent results related to this field. In the case of the GSTP1 A/G gene polymorphism was shown an increased incidence of breast cancer in Asian women, while this relationship in European and African women was not found. Similarly. In the case of cardiovascular diseases, the differences in the influence of GSTM1, GSTT1, GSTP1 and GSTA1 polymorphisms on their development or lack of it depending on the continent were shown. These examples show that the development of the above-mentioned diseases is not only influenced by genetic changes, but their pathophysiology is more complex. The mere presence of a specific genotype within a studied polymorphism may not predispose to cancer, but in combination with environmental factors, which often depend on the place of residence, it may elevate the chance of developing the selected disease.

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.

Susceptibility of Glutathione--S-Transferase Polymorphism to CVD Development in Type 2 Diabetes Mellitus - A Review

BACKGROUND

Metabolic disorder affects normal homeostasis and can lead to the development of diseases. Diabetes mellitus is the most common metabolic disorder, and a cluster of metabolic conditions can lead to cardiovascular disease (CVD) development. Diabetes mellitus and CVD are closely related, with oxidative stress, playing a major role in the pathophysiology. Glutathione-S-Transferases (GST) potentially play an important role by reducing oxidative stress and is found to be the underlying pathophysiology in the development of diabetes, cardiovascular diseases (CVD), etc. Objectives: In this review, the role of GST genetic variant in the development of diabetes mellitus, CVD and diabetic vascular complications has been focused.

RESULTS

Based on the literature, it is evident that the GST can act as an important biochemical tool providing significant evidence regarding oxidative stress predominant in the development of diseases. Analysis of GST gene status, particularly detection of GSTM1 and GSTT1 null mutations and GSTP1 polymorphism, have clinical importance.

CONCLUSION

The analysis of GST polymorphism may help identify the people at risk and provide proper medical management. Genotyping of GST gene would be a helpful biomarker for early diagnosis of CVD development in DM and also in CVD cases. More studies focusing on the association of GST polymorphism with CVD development in diabetic patients will help us determine the pathophysiology better.

Association of GSTP1 Ile105Val polymorphism with the risk of coronary heart disease: An updated meta-analysis

Background

Numerous case-control studies have investigated the association between GSTP1 Ile105Val polymorphism and CHD risk, but the results from published studies were inconclusive. The present meta-analysis was performed to derive a more precise estimation.

Methods

PubMed, EMBASE, and Web of Science database searches were conducted to retrieve relevant articles.

Results

Ultimately, 5,451 CHD cases and 5,561 controls from 15 studies were included. Pooled analysis did not yield any statistically significant association between GSTP1 Ile105Val polymorphism and CHD risk for the overall population (Val vs. Ile: OR, 1.05; 95% CI, 0.93 to 1.18; Val/Val vs. Ile/Ile: OR, 1.09; 95% CI, 0.83 to 1.42; Val/Ile vs. Ile/Ile: OR, 1.09; 95% CI, 0.93 to 1.28; Val/Val vs. Val/Ile+Ile/Ile: OR, 1.04; 95% CI, 0.83 to 1.30; Val/Val+Val/Ile vs. Ile/Ile: OR, 1.14; 95% CI, 0.97 to 1.33). Subgroup analyses and sensitivity analyses indicated that GSTP1 Ile105Val polymorphism was still not associated with an increased risk of CHD. After excluding studies detected by Galbraith plots as major sources of heterogeneity, these relationships were still not significant.

Conclusions

The overall results did not reveal a major role of the GSTP1 Ile105Val polymorphism in modulating CHD risk. Well-designed studies with large sample sizes are needed to validate our findings and explore the possible gene-gene or gene-environment interactions.

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.

Associations between nine candidate genetic polymorphisms with coronary heart disease : A meta-analysis

BACKGROUND

The aim of this study was to obtain a more accurate assessment of the potential association between nine genetic polymorphisms and the risk of coronary heart disease (CHD).

METHODS

A literature search was performed in PubMed, Embase, OVID, Web of Science, Wanfang, and Chinese National Knowledge Infrastructure (CNKI) databases to identify eligible studies. We analyzed the odds ratios (OR) and 95% confidence intervals (CI) to assess the strength of the associations.

RESULTS

A significant association was found between the PON1 -108C/T polymorphism and CHD risk (TT vs. CC: OR = 1.67, 95% CI = 1.14-2.47, p = 0.009; CT vs. CC: OR = 1.47, 95% CI = 1.17-1.85, p = 0.001; [TT + CT] vs. CC: OR = 1.56, 95% CI = 1.18-2.06, p = 0.002; T allele vs. C allele: OR = 1.28, 95%CI = 1.06-1.54, p = 0.011). There was a significant association between the hOGG1 +1245C/G polymorphism and CHD (GG vs. CC: OR = 2.33, 95% CI: 1.19-4.56, p = 0.014; CG vs. CC: OR = 1.36, 95% CI: 1.01-1.83, p = 0.046; [GG + CG] vs. CC: OR = 1.46, 95% CI: 1.10-1.94, p = 0.010; GG vs. [CC+CG]: OR = 2.11, 95% CI: 1.08-4.10, p = 0.028; G allele vs. C allele: OR = 1.45, 95% CI: 1.14-1.84, p = 0.002). The results also showed a statistically significant association of the SCARB1 +1050C/T polymorphism with CHD (TT vs. CC: OR = 1.30, 95% CI = 1.04-1.62, p = 0.022). Meta-analyses of the other six polymorphisms suggested a lack of any association with CHD risk.

CONCLUSION

Our results show that the susceptibility to CHD was associated with three polymorphisms: PON1 -108C/T, hOGG1 +1245C/G, and SCARB1 +1050C/T.

Association of Glutathione S-Transferase theta 1 and mu 1 Genes Polymorphisms with the Susceptibility of Myocardial Infarction in Bangladesh

Background

Myocardial infarction is one of the leading causes of morbidity and mortality worldwide. Oxidative stress plays a vital role in the pathogenesis of atherosclerosis leading to myocardial infarction and Glutathione S-transferases (GSTs) act as detoxifying enzymes to reduce oxidative stress. The aim of the present study was to investigate the associations of the GST (T1 & M1) gene polymorphism with the susceptibility of myocardial infarction in the Bangladeshi population.

Methods

A case-control study on 100 cardiac patients with MI and 150 control subjects was conducted. The genotyping of GST (T1 & M1) gene was done using conventional Polymerase Chain Reaction.

Results

The percentage of GSTM1 genotypes was significantly (p< 0.01) lower in patients compared to control subjects while the GSTT1 genotypes were not significantly different between the study subjects. The individual with GSTM1 null allele was at 2.5-fold increased risk {odds ratio (OR)= 2.5; 95 % confidence interval (95 % CI)= 1.4 to 4.3; p< 0.01} of experiencing MI while individual with either GSTM1 or GSTT1 genotypes was at lower risk. In the case of GST M1 and GST T1 combined genotype, patients having both null genotypes for GST M1 and GST T1 gene showed significantly (p< 0.01) higher risk of experiencing MI when compared to control subjects (OR= 3.5; 95% CI= 1.7-7.2; p< 0.001).

Conclusion

Thus our recent study suggested that GSTM1 alone and GSTM1 and T1 in combination augments the risk of MI in Bangladeshi population.

Association of GSTP1, GSTT1 and GSTM1 Gene Variants with Coronary Artery Disease in Iranian Population: A Case-Control Study

Background

Coronary artery disease (CAD) is a multifactorial disease that may be caused by the interaction between environmental and genetic risk factors. Glutathione S-transferases (GSTs) are known to participate in detoxification and metabolism of a wide range of xenobiotic compounds and oxidative stress products. Considering the interaction between environmental and genetic factors in CAD, we investigated the genetic polymorphisms of GSTM1, GSTT1, and GSTP1 in the Iranian population.

Patients and Methods

Two hundred and forty-four CAD cases and 281 healthy controls were studied. The genotype of GSTM1, GSTT1, and GSTP1 genes was determined by multiplex polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP) techniques. Multivariable logistic regression analysis was used to calculate the odds ratios (ORs) and 95% confidence intervals (CI). Multifactor dimensionality reduction (MDR) analysis was also carried out to analyze the gene–gene and gene–environment interaction.

Results

The genotype and allele distribution of the three variations were not significantly different between CAD patients and controls (p > 0.05). The subgroup analysis revealed no significant gene–gene interactions or gene–gene combination effects linked to CAD susceptibility. However, MDR analysis selected the GSTM, GSTT pairwise and three genes combination models associated with the susceptibility to CAD. In addition, its result revealed that smoking in combination with GSTM1 (two-way) and GSTT, GSTP (three-way) genes might increase the risk of CAD. Furthermore, a significant interaction between GSTT1-null polymorphism and dyslipidemia was found in multivariable logistic regression analyses in the gene–environmental interactions on CAD risk.

Conclusion

Our results suggest that the GSTM1, GSTT1 and GSTP1 genetic variations are not directly associated with the susceptibility to CAD in Iranian patients. Due to MDR results, there might be a non-linear association between interactions of two or three genes and smoking with CAD. There is also an association between CAD risk factors and GST variations, which requires supplementary confirmation with larger sample sizes.

Glutathione Transferase P1 Polymorphism Might Be a Risk Determinant in Heart Failure

Disturbed redox balance in heart failure (HF) might contribute to impairment of cardiac function, by oxidative damage, or by regulation of cell signaling. The role of polymorphism in glutathione transferases (GSTs), involved both in antioxidant defense and in regulation of apoptotic signaling pathways in HF, has been proposed. We aimed to determine whether GST genotypes exhibit differential risk effects between coronary artery disease (CAD) and idiopathic dilated cardiomyopathy (IDC) in HF patients. GSTA1, GSTM1, GSTP1, and GSTT1 genotypes were determined in 194 HF patients (109 CAD, 85 IDC) and 274 age- and gender-matched controls. No significant association was found for GSTA1, GSTM1, and GSTT1 genotypes with HF occurrence due to either CAD or IDC. However, carriers of at least one variant GSTP1∗Val (rs1695) allele were at 1.7-fold increased HF risk than GSTP1∗Ile/Ile carriers (p = 0.031), which was higher when combined with the variant GSTA1∗B allele (OR = 2.2, p = 0.034). In HF patients stratified based on the underlying cause of disease, an even stronger association was observed in HF patients due to CAD, who were carriers of a combined GSTP1(rs1695)/GSTA1 "risk-associated" genotype (OR = 2.8, p = 0.033) or a combined GSTP1∗Ile/Val+Val/Val (rs1695)/GSTP1∗AlaVal+∗ValVal (rs1138272) genotype (OR = 2.1, p = 0.056). Moreover, these patients exhibited significantly decreased left ventricular end-systolic diameter compared to GSTA1∗AA/GSTP1∗IleIle carriers (p = 0.021). Higher values of ICAM-1 were found in carriers of the GSTP1∗IleVal+∗ValVal (rs1695) (p = 0.041) genotype, whereas higher TNFα was determined in carriers of the GSTP1∗AlaVal+∗ValVal genotype (rs1138272) (p = 0.041). In conclusion, GSTP1 polymorphic variants may determine individual susceptibility to oxidative stress, inflammation, and endothelial dysfunction in HF.

Association between Polymorphisms of Antioxidant Gene (MnSOD, CAT, and GPx1) and Risk of Coronary Artery Disease

Objective

Reactive oxygen species (ROS) been cited as one of the major causes of atherosclerosis and coronary artery disease which are possible agents inducing DNA damage. Manganese superoxide dismutase (MnSOD), catalase (CAT), and glutathione peroxidase-1 (GPx1) have evolved to address primary defense against free radical mediated damage in mitochondria. The aim of this study was to delineate the association of MnSOD, CAT, and GPx1 polymorphisms and risk of CAD in Taiwan.

Methods

We conducted a case-control study with 657 participants recruited at a medical center. All subjects were evaluated by noninvasive stress test and then quantitative coronary angiography to confirm the diagnosis of CAD. 447 CAD cases were defined as >50% stenosis of coronary artery and 210 controls were stenosed below 50%. Polymorphisms of MnSOD (Val16Ala), CAT (C-262T), and GPx1 (Pro198Leu) genes were determined by polymerase chain reaction methods. Multivariate logistic regression model was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs).

Results

The MnSOD Val/Ala+Ala/Ala genotype was significantly associated with an increased risk of CAD compared to the Val/Val genotype (OR = 1.86, 95% CI = 1.15-3.01). This polymorphism was also associated with the severity of CAD of single and two vessel diseases. The corresponding ORs were 2.31 (95% CI = 1.32-4.03) and 1.92 (95% CI = 1.02-3.61), respectively. Among cigarette smokers, the harmful genetic effect of MnSOD Ala allele on CAD risk was much higher (OR = 2.23, 95% CI = 1.02-4.88). However, the interaction between MnSOD genotype and cigarette smoking on CAD risk was not significant. No significant association between CAT and GPx1 polymorphisms and CAD risk was observed.

Conclusion

Our results suggest that MnSOD polymorphism is an independent risk factor for susceptibility to CAD in the Chinese population.

Glutathione S-transferase P1 gene polymorphisms and susceptibility to coronary artery disease in a subgroup of north Indian population

The present study aimed to investigate the association of g.313A>G and g.341C>T polymorphisms of GSTP1 with coronary artery disease (CAD) in a subgroup of north Indian population. In the present case-control study, CAD patients (n = 200) and age-matched, sex-matched and ethnicity-matched healthy controls (n = 200) were genotyped for polymorphisms in GSTP1 using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Genotype distribution of g.313A>Gand g.341C>T polymorphisms of GSTP1 gene was significantly different between cases and controls (P = 0.005 and 0.024, respectively). Binary logistic regression analysis showed significant association of A/G (odds ratio (OR): 1.6, 95% CI: 1.08-2.49, P = 0.020) and G/G (OR: 3.1, 95% CI: 1.41-6.71, P = 0.005) genotypes of GSTP1 g.313A>G, and C/T (OR: 5.8, 95% CI: 1.26-26.34, P = 0.024) genotype of GSTP1 g.341C>T with CAD. The A/G and G/G genotypes of g.313A>G and C/T genotype of g.341C>T conferred 6.5-fold increased risk for CAD (OR: 6.5, 95% CI: 1.37-31.27, P = 0.018).Moreover, the recessive model of GSTP1 g.313A>G is the best fit inheritance model to predict the susceptible gene effect (OR: 2.3, 95% CI: 1.11-4.92, P = 0.020). In conclusion, statistically significant associations of GSTP1 g.313A>G (A/G, G/G) and g.341C>T (C/T) genotypes with CAD were observed.

Genetic susceptibility of glutathione S-transferase genes (GSTM1/T1 and P1) to coronary artery disease in Asian Indians

Genetic polymorphisms in glutathione S-transferase (GST) genes may modulate the risk of cardiovascular diseases. The objective of present study was to investigate the potential association between the polymorphisms of GSTM1/T1 and P1 genes and their influence on diverse clinical parameters and oxidative stress biomarkers in coronary artery disease (CAD) patients in Asian Indians. The present study includes 562 angiographically confirmed CAD patients and 564 healthy control subjects from the north Indian population. Anthropometric and clinical measurements were performed for all the participants. The oxidative stress biomarkers including malondialdehyde and total antioxidant capacity were also measured. The genotyping of the GSTM1/T1 and P1 genes was performed using the multiplex-PCR and PCR-RFLP methods. The CAD patients exhibit significantly high values of waist circumference, waist-to-hip ratio, body fat (%), glucose, triglycerides, and very low-density lipoprotein, and reduced high-density lipoprotein levels compared to control subjects (P < 0.001). Malondialdehyde levels were significantly enhanced, and the total antioxidant capacity was reduced in CAD patients compared to controls (P < 0.001). However, no significant difference in body mass index and total cholesterol levels were observed in CAD patients and control subjects. The frequencies of the GSTM1 and GSTM1/T1 null genotypes in the CAD patients were significantly higher than the control subjects. In contrast, the GSTT1(-) genotype frequencies were significantly lower in CAD patients than the controls. Logistic regression analysis of the data revealed the null genotype of GSTM1 and the GG genotype of the GSTP1 (313A/G) gene were associated with an approximately twofold enhanced risk of developing CAD, whereas GSTT1(-) plays a defensive role against CAD development in north Indians. Upon stratification of data according to the genotypes of the GSTM1/T1 and P1 genes, we did not find significant a difference among the various metabolic traits in CAD patients and controls. Our results suggest that oxidative damage induced by lipid peroxidation with reduced antioxidant capacity and genetic variants in GST genes (GSTM1/T1 and P1) may modify the risk of CAD development in Asian Indian population.

Epistasis analysis of metabolic genes polymorphisms associated with ischemic heart disease in Yucatan

OBJECTIVE

Epistasis is a type of genetic interaction that could explain much of the phenotypic variability of complex diseases. In this work, the effect of epistasis of metabolic genes and cardiovascular risk on the susceptibility to the development of ischemic heart disease in Yucatan was determined.

METHODS

Case-control study in 79 Yucatecan patients with ischemic heart disease and 101 healthy controls matched by age and origin with cases. The polymorphisms -108CT, Q192R, L55M (paraoxonase 1; PON1), C677T, A1298C (methylenetetrahydrofolate reductase; MTHFR), and the presence/absence of the glutathione S-transferase T1 (GSTT1) gene were genotyped. Epistasis analysis was performed using the multifactorial dimensional reduction method. The best risk prediction model was selected based on precision (%), statistical significance (P<0.05), and cross-validation consistency.

RESULTS

We found an independent association of the null genotype GSTT1*0/0 (OR=3.39, CI: 1.29-8.87, P=0.017) and the null allele (OR=1.86, CI: 1.19-2.91, P=0.007) with ischemic heart disease. The GSTT1*0 deletion and the 677TT genotype (MTHFR) were identified as being at a high cardiovascular risk, whereas the GSTT1*1 wild type genotype and the CC677 variant were at low risk. The gene-environment interaction identified the GSTT1 gene, C677T polymorphism (MTHFR), and hypertension as the factors that best explain ischemic heart disease in the study population.

CONCLUSIONS

The interaction of the MTHFR, GSTT1 and hypertension may constitute a predictive model of risk for early onset ischemic heart disease in the population of Yucatan.

Combined GSTM1 and GSTT1 null genotypes are strong risk factors for atherogenesis in a Serbian population

Oxidative stress (OS) plays an important role in atherogenesis and since glutathione S-transferases (GSTs) provide protection against OS, we have tested the hypothesis that deletion polymorphisms in two GSTs (GSTM1 and GSTT1) may affect the risk of developing atherosclerosis. A total of 382 individuals (200 patients with atherosclerosis and 182 healthy controls) were included in this association study. Genomic DNA was isolated from peripheral blood cells or from buccal epithelial cells and genotyping was performed using multiplex-PCR or real-time PCR methods. GSTM1 null genotype was significantly more frequent in atherosclerotic patients than in controls (52.0% vs 34.1%) and individuals with the GSTM1 null genotype had an approximately 2-fold increase in atherosclerosis risk (OR: 2.1, 95%CI=1.39-3.17, P=0.0004). GSTT1 null genotype alone did not show a statistically significant effect on atherosclerosis risk modulation, but the association approached significance (OR: 1.57, 95%CI=0.94-2.64, P=0.08). The combined analysis showed that the presence of both genes had a protective effect against atherosclerosis (OR=0.55, 95%CI=0.37-0.83, P=0.005) while double null genotypes led to a robust atherosclerosis risk increase (OR: 8.14, 95%CI= 2.41-27.51, P < 0.0001). This study demonstrated that the GSTM1 null and combined GSTM1/GSTT1 null genotypes are susceptibility factors for development of atherosclerosis in a Serbian population.

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.

Cross-talk between clinical and host-response parameters of periodontitis in smokers

BACKGROUND AND OBJECTIVE

Periodontal diseases are a major public health concern leading to tooth loss and have also been shown to be associated with several chronic systemic diseases. Smoking is a major risk factor for the development of numerous systemic diseases, as well as periodontitis. While it is clear that smokers have a significantly enhanced risk for developing periodontitis leading to tooth loss, the population varies regarding susceptibility to disease associated with smoking. This investigation focused on identifying differences in four broad sets of variables, consisting of: (i) host-response molecules; (ii) periodontal clinical parameters; (iii) antibody responses to periodontal pathogens and oral commensal bacteria; and (iv) other variables of interest, in a population of smokers with (n = 171) and without (n = 117) periodontitis.

MATERIAL AND METHODS

Bayesian network structured learning (BNSL) techniques were used to investigate potential associations and cross-talk between the four broad sets of variables.

RESULTS

BNSL revealed two broad communities with markedly different topology between the populations of smokers, with and without periodontitis. Confidence of the edges in the resulting network also showed marked variations within and between the periodontitis and nonperiodontitis groups.

CONCLUSION

The results presented validated known associations and discovered new ones with minimal precedence that may warrant further investigation and novel hypothesis generation. Cross-talk between the clinical variables and antibody profiles of bacteria were especially pronounced in the case of periodontitis and were mediated by the antibody response profile to Porphyromonas gingivalis.

Association of GSTT1 and GSTM1 gene polymorphisms with coronary artery disease in North Indian Punjabi population: a case-control study

BACKGROUND

Glutathione S-transferases are metabolic enzymes which are responsible for detoxification of endogenous (products of oxidative stress) as well as exogenous (drugs, pesticides, herbicides, environmental pollutants and carcinogens) products. Dysfunctional detoxification enzymes are responsible for the production of oxidative stress; a major contributor to the development of coronary artery disease (CAD).

OBJECTIVES

The present case-control study aimed to investigate the association of GSTT1 and GSTM1 gene polymorphisms with CAD.

METHODS

In the present study, 200 patients diagnosed with CAD and 200 age, sex and population subgroup matched healthy controls were enrolled. The GSTT1 and GSTM1 gene polymorphisms were examined using multiplex PCR.

RESULTS

The frequency of GSTT1 null genotype was significantly (p=0.038) lower in patients with CAD (6.00%) than in controls (12.50%). The GSTT1 null genotype showed protection against CAD (OR=0.45, 95% CI 0.22 to 0.92, p=0.028). The frequency of GSTM1 null genotype was significantly (p=0.004) higher in patients (31%) compared with controls (18%). The GSTM1 null genotype conferred twofold increased risk of developing CAD (OR=2.05, 95% CI 1.28 to 3.27, p=0.003).

CONCLUSIONS

The results concluded that the GSTT1 null genotype showed protection against CAD while the GSTM1 null genotype might be involved in the pathogenesis and development of CAD.

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.

Smoking-related cotinine levels and host responses in chronic periodontitis

BACKGROUND AND OBJECTIVE

Smoking has been reported to increase the risk of periodontal disease by disrupting the balance of immune responses and tissue repair processes; however, this risk varies among smokers. Cotinine levels in saliva are routinely used to measure the level of smoking, and reflect the quantity of nicotine, and other smoking-related xenobiotics that challenge host systems. This study delineated characteristics of inflammatory mediators in saliva and serum antibody responses to both periodontal pathogens and commensal bacteria in smokers as they related to cotinine levels.

MATERIALS AND METHODS

This case-control study (n = 279) examined salivary inflammatory mediator responses [interleukin (IL)-1ß, IL-10, prostaglandin E2, myeloperoxidase and plasminogen activator inhibitor-1], and serum IgG antibody responses to three periodontal pathogens (Aggregatibacter actinomyce-temcomitans, Porphyromonas gingivalis, Treponema denticola) and five commensal oral microorganisms (Veillonella parvula, Streptococcus sanguis, Prevotella loescheii, Actinomyces naeslundii, Capnocytophaga ochracea).

RESULTS

The patients were stratified into health (n = 30), gingivitis (n = 55) and periodontitis (n = 184); cotinine levels correlated with reported smoking habits in health, less so with gingivitis, and were not correlated in periodontitis. Of the inflammatory mediators/acute phase proteins, only IL-1ß levels were positively associated (p < 0.001) with the pack years and cotinine levels. As might be predicted, patients with periodontitis smoked more (p < 0.001) and had higher levels of cotinine. IL-1ß and antibody to A. actinomycetemcomitans, P. gingivalis and T. denticola were significantly higher in the patients with periodontitis than either patients with gingivitis or who were healthy.

CONCLUSIONS

Generally, antibody to the pathogens and commensals was lower with decreased cotinine levels. Smoking exacerbated differences in both inflammatory mediators and three antibody in periodontal disease compared to healthy subjects.