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

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.

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.

DNA repair and metabolic gene polymorphisms affect genetic damage due to diesel engine exhaust exposure

Diesel engine exhaust (DEE) is a complex mixture of toxic gases, halogenated aromatic hydrocarbons, alkyl polycyclic aromatic hydrocarbons, polycyclic aromatic hydrocarbons, benzene derivatives, metals and diesel exhaust particles (DEPs) generated from the incomplete combustion of diesel fuel. Many of the compounds in this mixture can cause oxidative damage to DNA and are considered carcinogenic for humans. Further, chronic DEE exposure increases risks of cardiovascular and pulmonary diseases. Despite these pervasive health risks, there is limited and inconsistent information regarding genetic factors conferring susceptibility or resistance to DEE genotoxicity. The present study evaluated the effects of polymorphisms in two base excision repair (BER) genes (OGG1 Ser326Cys and XRCC1 Arg280His), one homologous recombination (HRR) gene (XRCC3 Thr241Met) and two xenobiotic metabolism genes (GSTM1 and GSTT1) on the genotoxicity profiles among 123 mechanics exposed to workplace DEE. Polymorphisms were determined by PCR-RFLP. In comet assay, individuals with the GSTT1 null genotype demonstrated significantly greater % tail DNA in lymphocytes than those with non-null genotype. In contrast, these null individuals exhibited significantly lower frequencies of binucleated (BN) cells and nuclear buds (NBUDs) in buccal cells than non-null individuals. Heterozygous hOGG1 326 individuals (hOGG1 326 Ser/Cys) exhibited higher buccal cell NBUD frequency than hOGG1 326 Ser/Ser individuals. Individuals carrying the XRCC3 241 Met/Met polymorphism also showed significantly higher buccal cell NBUD frequencies than those carrying the XRCC3 241 Thr/Thr polymorphism. We found a high flow of particulate matter with a diameter of < 2.5 μm (PM_2.5) in the workplace. The most abundant metals in DEPs were iron, copper, silicon and manganese as detected by transmission electron microscopy-energy-dispersive X-ray spectroscopy (TEM-EDX). Scanning electron microscopy (SEM-EDS) revealed particles with diameters smaller than PM_2.5, including nanoparticles forming aggregates and agglomerates. Our results demonstrate the genotoxic effects of DEE and the critical influence of genetic susceptibility conferred by DNA repair and metabolic gene polymorphisms that shed light into the understanding of underlying mechanisms.

Role of anabolic agents in colorectal carcinogenesis: Myths and realities (Review)

Colorectal cancer (CRC) is one of the four leading causes of cancer‑related mortality worldwide. Even though over the past few decades the global scientific community has made tremendous efforts to understand this entity, many questions remain to be raised on this issue and even more to be answered. Epidemiological findings have unveiled numerous environmental and genetic risk factors, each one contributing to a certain degree to the final account of new CRC cases. Moreover, different trends have been revealed regarding the age of onset of CRC between the two sexes. That, in addition to newly introduced therapeutic approaches for various diseases based on androgens, anti‑androgens and anabolic hormones has raised some concerns regarding their possible carcinogenic effects or their synergistic potential with other substances/risk factors, predisposing the individual to CRC. Notably, despite the intense research on experimental settings and population studies, the conclusions regarding the majority of anabolic substances are ambiguous. Some of these indicate the carcinogenic properties of testosterone, dihydrotestosterone (DHT), growth hormone and insulin‑like growth factor (IGF) and others, demonstrating their neutral nature or even their protective one, as in the case of vitamin D. Thus, the synergistic nature of anabolic substances with other CRC risk factors (such as type 2 diabetes mellitus, metabolic syndrome and smoking) has emerged, suggesting a more holistic approach.

Association between intake of fruits and vegetables by pesticide residue status and coronary heart disease risk

BACKGROUND

Fruit and vegetable (FV) intake is recommended for the prevention of coronary heart disease (CHD). FVs are also an important source of exposure to pesticide residues. Whether the relations of FV intake with CHD differ according to pesticide residue status is unknown.

OBJECTIVE

To examine the associations of high- and low-pesticide-residue FVs with the risk of CHD.

METHODS

We followed 145,789 women and 24,353 men free of cardiovascular disease and cancer (excluding non-melanoma skin cancer) at baseline and participating in three ongoing prospective cohorts: the Nurses' Health Study (NHS: 1998-2012), the NHS-II (1999-2013), and the Health Professionals Follow-up Study (HPFS: 1998-2012). FV intake was assessed via food frequency questionnaires. We categorized FVs as having high- or low-pesticide-residues using a validated method based on pesticide surveillance data from the US Department of Agriculture. Multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95%CI) of CHD in relation to high- and low-pesticide-residue FV intake.

RESULTS

A total of 3707 incident CHD events were identified during 2,241,977 person-years of follow-up. In multivariable-adjusted models, a greater intake of low-pesticide-residue FVs was associated with a lower risk of CHD whereas high-pesticide-residue FV intake was unrelated to CHD risk. Specifically, compared with individuals consuming <1 serving/day of low-pesticide-residue FVs, those consuming ≥4 servings/day had 20% (95CI: 4%, 33%) lower risk of CHD. The corresponding HR (comparing ≥4 servings/day to <1 serving/day) for high-pesticide-residue FV intake and CHD was 0.97 (95%CI: 0.72, 1.30).

CONCLUSIONS

Our data suggested exposure to pesticide residues through FV intake may modify some cardiovascular benefits of FV consumption. Further confirmation of these findings, especially using biomarkers for assessment of pesticide exposure, is needed.

Correlation analysis of mRNA expression and prognosis of hOGG1 gene polymorphism in patients with non-small cell lung cancer

Level of mRNA expression and gene polymorphism of human 8-hydroxyguanine glycosidase 1 (hOGG1) in patients with non-small cell lung cancer (NSCLC) were investigated. A polymorphism analysis of hOGG1 gene rs1052133 locus in 182 NSCLC patients (NSCLC group) surgically treated in Xiang Yang No. 1 People's Hospital, Hubei University of Medicine from January 2008 to January 2012 and 200 healthy individuals (control group) was performed. The expression level of hOGG1 was compared between cancer tissues and adjacent tissues of NSCLC patients, and the survival rate was analyzed. The expression level of hOGG1 was significantly higher in cancer tissues than that in adjacent tissues (P<0.001). Taqman probe method was used to detect the genotypes of hOGG1 polymorphism locus rs1052133, with the genotype distribution frequencies of NSCLC group (P=0.411) and control group (P=0.354) consistent with the Hardy-Weinberg equilibrium. The proportion of C/C gene was significantly higher in NSCLC group than that in control group (P=0.008, OR=2.2, 95%, CI=1.27–4.52). The median value of the hOGG1 expression level in detection results as the boundary, NSCLC patients were divided into hOGG1 high expression group (≥3.61) with 91 cases and hOGG1 low expression group (<3.61) with 91 cases. The 1-, 2- and 3-year survival rates of patients in hOGG1 low expression group were significantly higher than those in hOGG1 high expression group (P=0.007). The 3-year survival rate in hOGG1 low expression group is significantly higher than that in hOGG1 high expression group (P=0.007). The sensitivity, specificity and AUC of hOGG1 to patient survival prediction were 83.33%, 64.29%, and 0.816, respectively. In conclusion, hOGG1 is highly expressed in NSCLC tissues. Compared to S/S and S/C genotypes, the C/C gene was found to be more common in NSCLC group than in control group. Thus, hOGG1 has a high predictive value for patient survival.

Chemotherapeutic-Induced Cardiovascular Dysfunction: Physiological Effects, Early Detection-The Role of Telomerase to Counteract Mitochondrial Defects and Oxidative Stress

Although chemotherapeutics can be highly effective at targeting malignancies, their ability to trigger cardiovascular morbidity is clinically significant. Chemotherapy can adversely affect cardiovascular physiology, resulting in the development of cardiomyopathy, heart failure and microvascular defects. Specifically, anthracyclines are known to cause an excessive buildup of free radical species and mitochondrial DNA damage (_mtDNA) that can lead to oxidative stress-induced cardiovascular apoptosis. Therefore, oncologists and cardiologists maintain a network of communication when dealing with patients during treatment in order to treat and prevent chemotherapy-induced cardiovascular damage; however, there is a need to discover more accurate biomarkers and therapeutics to combat and predict the onset of cardiovascular side effects. Telomerase, originally discovered to promote cellular proliferation, has recently emerged as a potential mechanism to counteract mitochondrial defects and restore healthy mitochondrial vascular phenotypes. This review details mechanisms currently used to assess cardiovascular damage, such as C-reactive protein (CRP) and troponin levels, while also unearthing recently researched biomarkers, including circulating _mtDNA, telomere length and telomerase activity. Further, we explore a potential role of telomerase in the mitigation of mitochondrial reactive oxygen species and maintenance of _mtDNA integrity. Telomerase activity presents a promising indicator for the early detection and treatment of chemotherapy-derived cardiac damage.

Oxidative stress in patients with refractory temporal lobe epilepsy and mesial temporal sclerosis: Possible association with major depressive disorder?

OBJECTIVE

The objective was to evaluate the genetic and biochemical profiles associated with oxidative stress (OS) in patients with temporal lobe epilepsy with mesial temporal sclerosis (TLE-MTS) and a healthy control group, and also to verify the possible existence of association between OS markers and psychiatric disorders (PD) in group with TLE-MTS.

METHODS

Forty-six patients with refractory TLE-MTS and 112 healthy controls were included. Psychiatric evaluation occurred through Diagnostical and Statistical Manual of Mental Disorders (DSM-5) criteria. A peripheral blood sample was collected for analysis of glutathione S-transferase (GST) T1/M1 polymorphisms and serum levels of malondialdehyde (MDA) and antioxidant capacity equivalent to the trolox (TEAC), serum markers of OS. Student's t-test, Fisher's exact test, Chi-square test, and Analysis of Variance (ANOVA) were used, with a significance level of P<0.05.

RESULTS

The PD were observed in 27 patients of the group with TLE-MTS (58.6%); major depressive disorder (MDD) was the most frequent. Serum levels of MDA (P<0.0001) and TEAC (P<0.0001) were higher in group with TLE-MTS. When patients with MDD were compared with patients without PD, significant differences were observed between MDA (P=0.002) and TEAC (P=0.003) serum levels. Patients with TLE-MTS and MDD presented higher levels when compared with patients with TLE-MTS without PD and with another PD except MDD.

CONCLUSIONS

The present study observed significantly higher serum levels of MDA and of TEAC in patients with refractory TLE-MTS in comparison with the control group. The MDD was observed as an important issue associated with higher OS levels in refractory TLE-MTS. Further studies are needed to investigate the association of OS, TLE-MTS, and PD.