Relationship between genotype and enzyme activity of glutathione S-transferases M1 and P1 in Chinese

Associations of GST Gene Polymorphisms and GST Enzyme Activity with the Development of Noise-Induced Hearing Loss in Chinese Han Males

INTRODUCTION

In noise-induced hearing loss (NIHL), glutathione S-transferases (GSTs) play a pivotal role as antioxidants in cochlear protection. Nevertheless, the variability in population and environmental factors complicates the interpretation of research findings on the association among GST gene polymorphism, GST enzyme activity, and NIHL, leading to inconsistent results. To explore the potential correlation between them, we took a cross-sectional survey.

METHODS

For workers with NIHL, standard 1:1 propensity score matching was applied to create a highly comparable control group. Multiplex PCR was used to detect GSTT1 and GSTM1 gene deletions, PCR-restriction fragment length polymorphism was used to detect the GSTP1 rs1695 gene polymorphism, and a GST assay kit was used to measure total plasma GST activity. Furthermore, we analyzed the relationship among GST gene polymorphism, GST enzyme activity, and NIHL.

RESULTS

This study included 144 workers with NIHL and 144 workers with normal hearing. The GSTM1 null genotype was significantly higher among workers with NIHL than controls (64.6% vs. 49.3%), regression analysis revealed a significant correlation between GSTM1 null genotype and elevated susceptibility to NIHL (p = 0.013). Workers with NIHL had significantly lower GST activity than healthy controls (p < 0.05). GST enzymes were not affected by GSTT1, GSTM1, or GSTP1 polymorphisms.

CONCLUSION

GSTM1 null genotype but not GSTM1 alone may confer susceptibility to NIHL, and serum GST enzyme activity is linked to NIHL.

Arsenic inorganic exposure, metabolism, genetic biomarkers and its impact on human health: A mini-review

Inorganic arsenic species exist in the environment as a result of both natural sources, such as volcanic and geothermal activities, and geological formations, as well as anthropogenic activities, including smelting, exploration of fossil fuels, coal burning, mining, and the use of pesticides. These species deposit in water, rocks, soil, sediments, and the atmosphere. Arsenic-contaminated drinking water is a global public health issue because of its natural prevalence and toxicity. Therefore, chronic exposure to arsenic can have deleterious effect on humans, including cancer and other diseases. This work describes the mechanisms of environmental exposure to arsenic, molecular regulatory factors involved in its metabolism, genetic polymorphisms affecting individual susceptibility and the toxic effects of arsenic on human health (oxidative stress, DNA damage and cancer). We conclude that the role of single nucleotide variants affecting urinary excretion of arsenic metabolites are highly relevant and can be used as biomarkers of the intracellular retention rates of arsenic, showing new avenues of research in this field.

Gene Variants Determine Placental Transfer of Perfluoroalkyl Substances (PFAS), Mercury (Hg) and Lead (Pb), and Birth Outcome: Findings From the UmMuKi Bratislava-Vienna Study

Prenatal exposure to perfluoroalkyl substances (PFAS), bisphenol A (BPA), lead (Pb), total mercury (THg), and methylmercury (MeHg) can affect fetal development. Factors influencing placental transfer rate of these toxins are poorly investigated. Whether prenatal exposure to pollutants has an effect on birth weight is incompletely understood. We therefore aimed (1) to determine placental transfer rates of PFAS, BPA, Pb, THg, and MeHg, (2) to analyze relationships between fetal exposure and birth outcome and (3) to analyze gene variants as mediators of placental transfer rates and birth outcome. Two hundred healthy pregnant women and their newborns participated in the study. BPA, 16 PFAS, THg, MeHg, and Pb were determined using HPLCMS/MS (BPA, PFAS), HPLC-CV-ICPMS (MeHg), CV-AFS (THg), and GF-AAS (Pb). Questionnaires and medical records were used to survey exposure sources and birth outcome. 20 single nucleotide polymorphisms and two deletion polymorphisms were determined by real-time PCR from both maternal and newborn blood. Genotype-phenotype associations were analyzed by categorical regression and logistic regression analysis. Specific gene variants were associated with altered placental transfer of PFAS (ALAD Lys59Asn, ABCG2 Gln141Lys), THg (UGT Tyr85Asp, GSTT1del, ABCC1 rs246221) and Pb (GSTP1 Ala114Val). A certain combination of three gene polymorphisms (ABCC1 rs246221, GCLM rs41303970, HFE His63Asp) was over-represented in newborns small for gestational age. 36% of Austrian and 75% of Slovakian mothers had levels exceeding the HBM guidance value I (2 μg/L) of the German HBM Commission for PFOA. 13% of newborns and 39% of women had Ery-Pb levels above 24 μg/kg, an approximation for the BMDL₀₁ of 12 μg/L set by the European Food Safety Authority (EFSA). Our findings point to the need to minimize perinatal exposures to protect fetal health, especially those genetically predisposed to increased transplacental exposure.

Independent and Interactive Effect of CYPs and GSTs Genetic Variants and Tobacco Smoking on the Risk of Non-Small Cell Lung Carcinoma

BACKGROUND

CYP and GST gene families detoxify tobacco carcinogens and have been linked to the risk of non-small cell lung carcinoma (NSCLC).

AIM

Independent and combined effects of CYP and GST genetic variations and smoking on the risk of non-small cell lung carcinoma (NSCLC) and its sub-histological types.

METHODS

We modelled an epistatic interaction via the effects of particular genotypes in two genes as OR (odds ratio), OR1, and OR2, a combination of both genotypes were characterized as OR_combine. In contrast, the two ORs' epistatic interaction for the individual genotypes has been represented as OR_interaction = OR_combine/(OR1 × OR2).

RESULTS

The variant genotypes of CYP2A6 (OR:4.2, p <0.001), GSTT1 (OR:3.9, p <0.001), and GSTM1 (OR: 4.5, p <0.001) were showed a significant risk with NSCLC. GSTM1 (del.)/CYP2A6 (variant) genotype was associated with a higher risk of NSCLC (OR:12.5, p <0.001). GSTM1 (del.)/CYP2A6 (Ser/Pro+Pro/Pro) and GSTM1 (del.)/CYP2A13 (CT+TT) interacted redundantly (OR_intraction = 0.66 and 0.64). A co-suppressive interaction was observed between GSTT1 (del.)/CYP2A6 (Ser/Pro+Pro/Pro) (OR_intraction = 0.41). Simultaneously, both GSTT1/GSTM1 del. genotype was associated with a significantly higher risk to NSCLC. In contrast, GSTT1 del./GSTM1 del. genotype interaction displayed a co-suppressive effect (OR_intraction = 0.15). CYP1A1(TC+CC)/CYP2A13(CT+TT)mutually interacted synergistically (OR_intraction = 1.27).CYP1A1 (TC+CC)/GSTP1 (Val/Val+Ile/Val) genotype demonstrated an additive (OR_intraction = 1) effect. GSTP1(Val/Val+Ile/Val) interacts with GSTT1 (del.) genotype exerted a suppressive effect (OR_intraction = 0.69). CYP2A6 in smokers increased risk by 4.2 (p = 0.001) to 5.6 fold (p <0.001), while GSTM1 and GSTT1 were independent of smoking.

CONCLUSION

Epistatic interactions revealed that CYPs/GSTs might follow a web of the interactions to modify the risk of NSCLC.

Status of Catalase, Glutathione Peroxidase, Glutathione S-Transferase, and Myeloperoxidase Gene Polymorphisms in Beta-Thalassemia Major Patients to Assess Oxidative Injury and Its Association with Enzyme Activities

Beta-thalassemic patients require regular blood transfusion to sustain their life which leads to iron overload and causes oxidative stress. The aim of this study was to investigate the status of variants in genes including GSTM1, GSTT1 (null/present), CT-262 (C > T) and CT-89 (A > T), glutathione peroxidase (GPx), and myeloperoxidase (MPO). The genotype studies were conducted with 200 thalassemia major (TM) patients and 200 healthy controls. Genotyping of GST gene was performed by multiplex polymerase chain reaction (PCR), whereas for CT, GPx and MPO genesvariants PCR- restriction fragment length polymorphism technique used. However, the enzyme activities were measured only in the patients group to assess the association with the genotypes. All enzyme estimations were performed by ELISA. We observed higher frequency of GSTT1 null, CT-89 (A > T), GPx1 198 (C > T) and MPO-463 (G > A) polymorphisms in TM patient than healthy controls. However, CT-262 (C > T) polymorphism was not found to be statistically significantly different between patients and controls. Our results suggest that frequency of null allele of glutathione-S-transferase is significantly high among TM patients. The other alleles CT-89 (A > T), GPx1 198 (C > T), and MPO-463 (G > A) are linked to decreased CT, GPX, and MPO enzyme activities.

As3MT and GST Polymorphisms Influencing Arsenic Metabolism in Human Exposure to Drinking Groundwater

The urinary arsenic metabolites may vary among individuals and the genetic factors have been reported to explain part of the variation. We assessed the influence of polymorphic variants of Arsenic-3-methyl-transferase and Glutathione-S-transferase on urinary arsenic metabolites. Twenty-two groundwater wells for human consumption from municipalities of Colombia were analyzed for assessed the exposure by lifetime average daily dose (LADD) (µg/kg bw/day). Surveys on 151 participants aged between 18 and 81 years old were applied to collect demographic information and other factors. In addition, genetic polymorphisms (GSTO2-rs156697, GSTP1-rs1695, As3MT-rs3740400, GSTT1 and GSTM1) were evaluated by real time and/or conventional PCR. Arsenic metabolites: As^III, As^V, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) were measured using HPLC-HG-AFS. The influence of polymorphic variants, LADD and other factors were tested using multivariate analyses. The median of total arsenic concentration in groundwater was of 33.3 μg/L and the median of LADD for the high exposure dose was 0.33 µg/kg bw/day. Univariate analyses among arsenic metabolites and genetic polymorphisms showed MMA concentrations higher in heterozygous and/or homozygous genotypes of As3MT compared to the wild-type genotype. Besides, DMA concentrations were lower in heterozygous and/or homozygous genotypes of GSTP1 compared to the wild-type genotype. Both DMA and MMA concentrations were higher in GSTM1-null genotypes compared to the active genotype. Multivariate analyses showed statistically significant association among interactions gene-gene and gene-covariates to modify the MMA and DMA excretion. Interactions between polymorphic variants As3MT*GSTM1 and GSTO2*GSTP1 could be potential modifiers of urinary excretion of arsenic and covariates as age, LADD, and alcohol consumption contribute to largely vary the arsenic individual metabolic capacity in exposed people.

Influence of DPYD*9A, DPYD*6 and GSTP1 ile105val Genetic Polymorphisms on Capecitabine and Oxaliplatin (CAPOX) Associated Toxicities in Colorectal Cancer (CRC) Patients

AIM

CAPOX treatment in CRC patients was reported to cause several dose-limiting toxicities, and are found responsible for treatment interruption or even discontinuation. Therefore there is a critical need for identifying the predictive biomarkers for such toxicities to prevent them. The aim of our present study is to find the influence of DPYD*9A, DPYD*6 and GSTP1 ile105val gene polymorphisms on CAPOX treatment-associated toxicities in south Indian patients with CRC.

PATIENTS AND METHODS

We have recruited 145 newly diagnosed and treatment naive CRC patients in the study. Each Patient received a standard treatment schedule of oxaliplatin 130 mg/m2 infusion over 2 hours on day 1 and oral capecitabine 1000mg/m2 in divided doses twice daily for the next 14 days of a 21-day cycle. 5 ml of the venous blood was collected from each patient and genomic DNA extraction and genotyping. The genotyping analysis of the selected genetic polymorphisms was carried out by real-time PCR using TaqMan SNP genotyping assays obtained from applied biosystems.

RESULTS

The major dose-limiting toxicities observed with CAPOX treatment were thrombocytopenia, HFS and PN. DPYD*9A carries were found to be at higher risk for HFS, diarrhoea and thrombocytopenia when compared to patients with wild allele. No significant association was found between DPYD*6, GSTP1 ile105val polymorphisms and CAPOX related toxicities except for thrombocytopenia.

CONCLUSION

A significant association was observed between DPYD*9A polymorphism and CAPOX induced dose-limiting toxicities strengthening its role as a predictive biomarker.

Glutathione S-transferase pi 1 variant and squamous cell carcinoma susceptibility: a meta-analysis of 52 case-control studies

Background

There are several meta-analyses on the genetic relationship between the rs1695 polymorphism within the GSTP1 (glutathione S-transferase pi 1) gene and the risk of different SCC (squamous cell carcinoma) diseases, such as ESCC (oesophageal SCC), HNSCC (head and neck SCC), LSCC (lung SCC), and SSCC (skin SCC). Nevertheless, no unified conclusions have been drawn.

Methods

Herein, an updated meta-analysis was performed to evaluate the probable impact of GSTP1 rs1695 on the susceptibility to different SCC diseases under six genetic models (allele, carrier, homozygote, heterozygote, dominant, and recessive). Three online databases, namely, PubMed, WOS (Web of Science), and Embase (Excerpta Medica Database), were searched.

Results

Initially, we obtained a total of 497 articles. Based on our selection criteria, we eventually included 52 case-control studies (9763 cases/15,028 controls) from 47 eligible articles. As shown in the pooling analysis, there was no difference in the risk of overall SCC disease between cases and controls [allele, P_a (P value of association test) = 0.601; carrier, P_a = 0.587; homozygote, P_a = 0.689; heterozygote, P_a = 0.167; dominant, P_a = 0.289; dominant, P_a = 0.548]. Similar results were obtained after stratification by race (Asian/Caucasian), genotyping, control source, and disease type (ESCC/HNSCC/LSCC/SSCC) (all P_a > 0.05).

Conclusion

The rs1695 polymorphism within the GSTP1 gene is not associated with the risk of overall SCC or a specific SCC type, including ESCC, HNSCC, LSCC, and SSCC.

Arsenic exposure, profiles of urinary arsenic species, and polymorphism effects of glutathione-s-transferase and metallothioneins

This study assessed the effects of polymorphic variants of gutathione-S-transferase and metallothioneins on profiles of urinary arsenic species. Drinking groundwater from Margarita and San Fernando, Colombia were analyzed and the lifetime average daily dose (LADD) of arsenic was determined. Specific surveys were applied to collect demographic information and other exposure factors. In addition, GSTT1-null, GSTM1-null, GSTP1-rs1695 and MT-2A-rs28366003 genetic polymorphisms were evaluated, either by direct PCR or PCR-RFLP. Urinary speciated arsenic concentrations were determined by HPLC-HG-AFS for species such as As^III, As^V, monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and total urinary As (TuAs). Primary methylation index (PMI) and secondary methylation index (SMI) were also calculated as indicators of the metabolic capacity. Polymorphisms effects were tested using multivariate analysis, adjusted by potential confounders. The As concentrations in groundwater were on average 34.6 ± 24.7 μg/L greater than the WHO guideline for As (10 μg/L). There was a correlation between As concentrations in groundwater and TuAs (r = 0.59; p = 0.000). Urinary inorganic arsenic (%InAs) was associated with GSTP1, LADD, GSTP1*Age, GSTP1*alcohol consumption (r² = 0.43; likelihood-ratio test, p = 0.000). PMI was associated with sex (r² = 0.20; likelihood-ratio test, p = 0.007). GSTP1 (AG + GG) homozygotes/heterozygotes could increase urinary %InAs and decrease the PMI ratio in people exposed to low and high As from drinking groundwater. Therefore, the explanatory models showed the participation of some covariates that could influence the effects of the polymorphisms on these exposure biomarkers to As.

The influence of glutathion S-transferase P-1 polymorphism A313G rs1695 on the susceptibility to cyclophosphamide hematologic toxicity in Indonesian patients

Background: Chemotherapy often causes side effects such as hematologic toxicity. The degree of toxicity is often associated with genetic polymorphism. This study aims to determine the influence of GSTP1 A313G polymorphism, an enzyme responsible for detoxifying cyclophosphamid, on incidence and severity of cyclophosphamid hematologic toxicity.Methods: 91 Indonesian females diagnosed with breast cancer at Haji Adam Malik Central General Hospital, Medan, receiving cyclophosphamide, doxorubicin/epirubicin and 5-FU were included in this retrospective cohort study. DNA was extracted from peripheral leukocytes and GSTP1 A313G genotyping was analyzed using polymerase chain reaction-restriction length fragment polymorphism (PCR-RFLP). Genotype deviation and allele frequencies were also determined by Hardy-Weinberg Equilibrium. The degrees of hematologic toxicity (leucopenia and neutropenia data after chemotherapy cycles 1 and 3) were collected from the patient medical records. The data were analyzed using chi-square test.Results: 60.4% of the patients had the wildtype (A/A), while 29.7% were heterozygous (A/G), and 9.9% were homozygous mutant (G/G). There was no significant deviation of allele and genotype frequency from Hardy-Weinberg Equilibrium. The G allele (A/G & G/G) contributes to more severe degree of leukopenia compared to patients with wild type allele (A/A)  (p<0.05) after the 3rd chemotherapy cycles.Conclusion: There was association between GSTP1 polymorphism with the degree of hematologic toxicity in breast cancer patients receiving cyclophosphamide chemotherapy regimen.

The Relationship Between Glutathione S-Transferase-P1 and Beta-2 Adrenoreceptor Genotypes with Asthmatic Patients in the Turkish Population

BACKGROUND

Individual differences in the activity of enzymes that metabolize xenobiotics can impact health and disease. Beta-2 adrenoreceptor (ADRB2) is a functional G-coupled protein expressed in the vascular endothelium of lungs, alveolar walls, and the ganglions of cholinergic nerves which induces bronchodilation in response to catecholamines. Glutathione S-Transferase-P1 (GSTP1) is a candidate pi class GST gene, which controls pi class glutathione S-transferase activity.

AIMS

In this study we determined the relationship between the ADRB2 Arg16Gly polymorphism and GSTP1 polymorphisms, involved in bronchodilator response and oxidative stress, respectively, with susceptibility to asthma.

METHODS

In this study, 129 asthmatic patients and 127 healthy control cases were recruited to determine ADRB2 and GSTP1 genotypes by allele-specific polymerase chain reaction and restriction fragment length polymorphism assays, respectively.

RESULTS

The ADRB2 genotype frequencies of the patients and control cases were found to be 10.9% (Arg16Arg), 48.8% (Arg16Gly), and 40.3% (Gly16Gly) and 24.4% (Arg16Arg), 36.2% (Arg16Gly), and 39.4% (Gly16Gly), respectively. GSTP1 genotype frequencies of patients and control cases were found to be 55% (Ile105Ile), 43.4% (Ile105Val), and 1.6% (Val105Val) and 75.6% (Ile105Ile), 22% (Ile105Val), and 2.4% (Val105Val), respectively. In the case of the GSTP1 gene, we found statistically significant differences in the genotype frequency of Ile105Val and the allele frequency of Val105 in the asthmatic group compared with the controls. Moreover, we observed a relationship between allele frequencies and clinical phenotypes including atopia nocturnal dyspnea, and steroid dependency in the asthmatic patients.

CONCLUSION

Our results suggest that the GSTP1 Ile105Val polymorphism may be linked to the severeness of airway dysfunction.

Glutathione S-transferase as a toxicity indicator in general anesthesia: genetics and biochemical function

General anesthesia may lead in patients to unexpected and adverse reactions including toxicity. Glutathione S-transferases (GSTs) are enzymes responsible for the detoxification process of anesthetic agents. Plasma and urine GST measurements are used in multiple studies as a hepatocellular integrity or renal injury indicator. The importance of GST enzyme measurements in monitoring the hepatotoxic and nephrotoxic effect in anesthetized patients is presented. The biochemical function and specific properties of GST render it a prognostic biomarker. This review demonstrates that GST can be valuable and promising toxicity indicator in patients undergoing general anesthesia.

Polymorphism of GST and FTO Genes in Risk Prediction of Cataract among a North Indian Population

BACKGROUND

The present study was carried out to investigate the association of GST and FTO gene polymorphisms with cataract cases and controls.

MATERIALS AND METHODS

The study included 131 cases and 126 controls. GST and FTO gene polymorphisms were evaluated by PCR-RFLP.

RESULTS

The frequency of the GSTM1-positive and GSTT1-positive in cataract cases were 62.13% and 86.40% while in the controls it was 46.39% and 95.87% with odds ratios of 1.9 (95% CI, 1.08-3.32; p value 0.025) and 0.27 (95% CI, 0.09-0.86; p value, 0.019) respectively. There was a statistically significant association between the GSTM1 null genotype and the risk of cataract development with an odds ratio of 0.43 (95% CI, 0.24-0.76; p value, 0.003). Significant differences were obtained in the frequencies of FTO AA and TT genotype (p = 0.023 and 0.023) between cases and controls.

CONCLUSION

The present study suggested that GSTM1, GSTT1 and FTO gene polymorphisms are associated with increased risk for cataract in North Indian populations. Due to the limited sample size, the finding on GST and FTO gene polymorphisms need further investigation.

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.

Association between glutathione S-transferase M1 polymorphism and urinary sodium excretion in a Brazilian population

BACKGROUND

Null genotypes of glutathione S-transferase (GST) exhibit the absence of enzymatic activity and are associated with increased cardiovascular risk. Recent reports have related both lower and higher urinary sodium excretion (USE) to higher cardiovascular risk. Here we investigate the impact of GSTM1 and GSTT1-null polymorphisms on USE in a Brazilian population.

METHODS

We cross-sectionally evaluated 1,308 subjects from the city of Vitoria, Brazil, based on clinical history, physical examination, anthropometry, analysis of laboratory parameters, measurement of USE, and GST polymorphisms genotyping.

RESULTS

The frequency of GST M1, T1, and double-deletion polymorphisms was 51%, 22%, and 11%, respectively. Individuals with the GSTM1-null genotype had lower USE than those with the non-null genotype (92.1±52.3 vs. 102.8 ± 6 0.7 mEq/12h; P < 0.001). Linear regression analysis adjusted for confounding factors revealed that the GSTM1-null genotype was independently associated with USE (P = 0.001). In addition, diastolic blood pressure and triglyceride levels were higher in GSTM1-null individuals than in non-null individuals in the highest tertile of USE. Finally, the presence of GSTT1-null or double-deleted genotypes did not influence USE or affect the interactions between USE and the variables studied.

CONCLUSIONS

Deletion of GSTM1 was associated with low USE and modulated the interaction between sodium intake and blood pressure in Brazilian subjects. These novel findings may provide a new unexplored link between sodium regulation and GST homeostasis.

Glutathione S-transferase M1 gene polymorphism is associated with susceptibility to impaired long-term allograft outcomes in renal transplant recipients

BACKGROUND

Despite improved post-transplantation care, progress in long-term kidney allograft survival of diabetic renal transplant recipients (pre-DM RTR) is worse than that of non-diabetic recipients (non-DM). We hypothesized that there are other potential risk factors, that predispose RTR to adverse renal allograft outcomes.

METHODS

A total of 323 transplant recipients who underwent renal transplantation between March 2000 and January 2008 were recruited. The composite end-point consisted of serum creatinine (SCr) doubling, graft failure, and death. Baseline clinical data were recorded, and polymerase chain reaction-restriction fragment length polymorphism measurements of interleukin (IL)-4, IL-10, IL-23, glutathione S-transferase (GST)A1, GSTM1, and GSTP1 polymorphisms were determined. The risk factors for developing the primary outcome were analyzed among these clinical and genetic factors.

RESULTS

Within a mean follow-up of 71.1 ± 24 months, there were 43 (13.3 %) patients with the primary outcome. Stepwise multivariate Cox regression analysis was used to determine the risk factors for the primary outcome of RTR. Renal transplant recipients who possessed the GSTM1 null genotype had a 2.2-fold risk (95 % CI: 1.10-4.40; P = 0.026) of developing the primary outcome. Additionally, RTR that had DM before transplantation (aHR: 3.31; 95 % CI: 1.77-6.20; P = 0.0002) or changes in SCr 6 to 12 months after transplantation (aHR: 2.83; 95 % CI: 1.29-6.19; P = 0.0095) had an increased risk of developing the primary outcome.

CONCLUSIONS

In addition to the adverse role played by DM, the GSTM1 null genotype also has an unfavorable influence on the long-term allograft outcome of RTR.

Association between GSTP1 Ile105Val polymorphism and oxaliplatin-induced neuropathy: a systematic review and meta-analysis

BACKGROUND AND AIMS

The association between glutathione-S-transferase P1 (GSTP1) Ile105Val polymorphism and oxaliplatin-induced neuropathy has been investigated in a number of published studies. However, most of these studies were based on small sample sizes and the results remained inconsistent. To assess the relationship between GSTP1 gene Ile105Val polymorphism and its susceptibility to oxaliplatin-induced neuropathy, a meta-analysis of previous studies was conducted.

METHODS

Two investigators independently searched studies published up to December 2012 from the databases of PubMed, EMBASE and The Cochrane Library. The pooled effect was calculated as odds ratio (OR) and corresponding 95 % confidence intervals (CIs) using fixed-effect or random-effect model.

RESULTS

Twelve prospective trials and two retrospective clinical trials involving 2,191 participants met the inclusion criteria. Combined analyses of these studies showed no significant associations between GSTP1 Ile105Val polymorphism and oxaliplatin-induced neuropathy, yielding OR of 1.08 (95 %CI 0.67-1.74, P = 0.754) in dominant model. Similar results were also obtained in recessive model (OR = 1.67, 95 %CI 0.56-4.93, P = 0.357) and allelic analysis (OR = 1.22, 95 %CI 0.67-2.24, P = 0.513). Since significant heterogeneity across studies, the pooled effects were calculated by random-effect model. No evidence of publication biases was identified in this meta-analysis.

CONCLUSION

This meta-analysis did not support the hypothesis that GSTP1 Ile105Val polymorphism was related to the occurrence of neurotoxicity in oxaliplatin-treated patients. Given the limited number of studies and potential bias, large-scale and well-designed clinical trials should be needed to confirm these hypotheses.

Genetic variation in GSTM1 is associated with susceptibility to noise-induced hearing loss in a Chinese population

OBJECTIVES

To investigate whether glutathione S-transferases (GST) genetic polymorphisms (GSTT1 rs1049055, GSTM1 rs10712361, and GSTP1 rs1695) are associated with susceptibility to noise-induced hearing loss (NIHL).

METHODS

These polymorphisms were analyzed in 444 NIHL and 445 normal hearing workers. In addition, total plasma GST activity was measured in all subjects.

RESULTS

Individuals with the GSTM1 null genotype had a statistically significantly increased risk of NIHL (odds ratio [OR] = 1.64, 95% confidence interval [CI] = 1.26 to 2.13) compared with those carrying a wild-type GSTM1 genotype. This effect was more pronounced among the workers exposed to 86 to 91 dB(A) (OR = 3.35, 95% CI = 1.54 to 7.31). Glutathione S-transferase activity of the NIHL workers was also lower than that of normal hearing workers (14.5 ± 5.1 U/ml vs 15.9 ± 6.3 U/ml, P = 0.010).

CONCLUSION

Our results suggest that GSTM1 polymorphism is associated with susceptibility to NIHL.

Association of glutathione S-transferase pi isoform single-nucleotide polymorphisms with exudative age-related macular degeneration in a Chinese population

PURPOSE

To investigate the association between single-nucleotide polymorphisms in the pi isoform of glutathione S-transferase (GSTP1) gene and the risk of exudative age-related macular degeneration (AMD) in a Chinese case-control cohort.

METHODS

A total of 131 Chinese patients with exudative AMD and 138 control individuals were recruited. Genomic DNA was extracted from venous blood leukocytes. Two common nonsynonymous single-nucleotide polymorphisms in GSTP1 (rs1695 and rs1138272) were genotyped by polymerase chain reaction followed by allele-specific restriction enzyme digestion and direct sequencing.

RESULTS

Significant association with exudative AMD was detected for single-nucleotide polymorphism, rs1695 (P = 0.019). The risk G allele frequencies were 21.8% in AMD patients and 12.7% in control subjects (P = 0.007). Compared with the wild-type AA genotype, odds ratio for the risk of AMD was 1.91 (95% confidence interval, 1.09-3.35) for the heterozygous AG genotype and 2.52 (95% confidence interval, 0.6-10.61) for the homozygous GG genotype. In contrast, rs1138272 was not associated with exudative AMD (P = 1.00). The risk G allele frequencies of rs1138272 were 0.4% in AMD patients and 0.4% in control subjects (P = 1.00).

CONCLUSION

Our data suggest that the GSTP1 variant rs1695 moderately increases the risk of exudative AMD. The variant rs1138272 was rare and was not associated with exudative AMD in this Chinese cohort.

Glutathione S-transferase gene polymorphisms are not major risks for susceptibility to posttransplantation diabetes mellitus in Taiwan renal transplant recipients

Glutathione S-transferase (GST) M1 null genotype has been reported playing a significant role in the diabetes mellitus (DM) susceptibility in Turkish population. We investigated whether the GSTM1, GSTA1, and GSTP1 gene polymorphisms are associated with posttransplantation diabetes mellitus (PTDM) in Taiwan. There were 283 renal transplant recipients (RTRs) enrolled. Polymerase chain reaction-restriction fragment length polymorphism was used for the measurement of GSTA1, M1, and P1 genetic polymorphisms. PTDM was diagnosed according to the American Diabetes Association guidelines. Eight-five patients (30%) were diagnosed with PTDM. The averaged posttransplant follow-up period was 77.9 ± 27.2 months. Duration from transplantat to diagnosis of PTDM ranged from 0.2 to 103.1 months (19.2 ± 26.3 months). There were significantly differences between non-DM and PTDM groups in age (50.6 ± 11.0 vs. 54.6 ± 9.36 years, P = 0.005), BMI (22.4 ± 3.6 vs. 24.3 ± 3.8, P<0.001). The distributions of GSTA1, GSTP1, and GSTM1 genotypes alleles were not significantly different between PTDM and non-DM group. Patients carrying the different GSTA1, GSTP1, and GSTM1 genetic and allelic polymorphisms had no differences for the development of PTDM. These overall results suggested a lack of strong association with GSTA1, GSTP1, and GSTM1 genetic polymorphisms to the susceptibility of PTDM in Taiwanese RTRs.

Impact of glutathione-S-transferase gene polymorphisms on enzyme activity, lung function and bronchial asthma susceptibility in Egyptian children

BACKGROUND

Asthma is a complex multifactorial disease with an obvious genetic predisposition. Polymorphisms of the glutathione-S-transferase (GST) genes are known risk factors for some environmentally-related diseases. The aim of the present study was to investigate the role of polymorphisms in the GSTT1, GSTM1 and GSTP1 genes and asthma susceptibility in Egyptian children, and to analyze their effect on GST activity and lung function.

METHODS

GSTT1 and GSTM1 gene polymorphism was genotyped using the multiplex polymerase chain reaction (PCR) and GSTP1 ILe105Val polymorphism was determined using PCR-restriction fragment length polymorphism (PCR-RFLP) in 168 healthy and 126 asthmatic children (82 atopic and 44 nonatopic). Also GST enzyme activity and lung function were evaluated.

RESULTS

Asthmatic children had a significant higher prevalence of the GSTM1 null (P=0.003) and significant lower prevalence of GSTP1 Val/Val genotypes (P=0.02) than control group. Lung function was significantly decreased in GSTM1 null genotype and GSTP1 Ile/Ile genotype. GSTP1 Val/Val genotypes and GSTM1 null genotype had a significant decrease in plasma GST activity.

CONCLUSIONS

GST genes polymorphisms may play an important role in pathogenesis and susceptibility to asthma in children.

A case-control study of polymorphisms in xenobiotic and arsenic metabolism genes and arsenic-related bladder cancer in New Hampshire

Arsenic is associated with bladder cancer risk even at low exposure levels. Genetic variation in enzymes involved in xenobiotic and arsenic metabolism may modulate individual susceptibility to arsenic-related bladder cancer. Through a population-based case-control study in NH (832 cases and 1191 controls), we investigated gene-environment interactions between arsenic metabolic gene polymorphisms and arsenic exposure in relation to bladder cancer risk. Toenail arsenic concentrations were used to classify subjects into low and high exposure groups. Single nucleotide polymorphisms (SNPs) in GSTP1, GSTO2, GSTZ1, AQP3, AS3MT and the deletion status of GSTM1 and GSTT1 were determined. We found evidence of genotype-arsenic interactions in the high exposure group; GSTP1 Ile105Val homozygous individuals had an odds ratio (OR) of 5.4 [95% confidence interval (CI): 1.5-20.2; P for interaction=0.03] and AQP3 Phe130Phe carriers had an OR=2.2 (95% CI: 0.8-6.1; P for interaction=0.10). Bladder cancer risk overall was associated with GSTO2 Asn142Asp (homozygous; OR=1.4; 95% CI: 1.0-1.9; P for trend=0.06) and GSTZ1 Glu32Lys (homozygous; OR=1.3; 95% CI: 0.9-1.8; P for trend=0.06). Our findings suggest that susceptibility to bladder cancer may relate to variation in genes involved in arsenic metabolism and oxidative stress response and potential gene-environment interactions requiring confirmation in other populations.

Individual variations in arsenic metabolism in Vietnamese: the association with arsenic exposure and GSTP1 genetic polymorphism

We investigated the association of As exposure and genetic polymorphism in glutathione S-transferase π1 (GSTP1) with As metabolism in 190 local residents from the As contaminated groundwater areas in the Red River Delta, Vietnam. Total As concentrations in groundwater ranged from <0.1 to 502 μg l(-1). Concentrations of dimethylarsinic acid (DMA(V)), monomethylarsonic acid (MMA(V)), and arsenite (As(III)) in human urine were positively correlated with total As levels in the groundwater, suggesting that people in these areas may be exposed to As through the groundwater. The concentration ratios of urinary As(III)/arsenate (As(V)) and MMA(V)/inorganic As (IA; As(III) + As(V))(M/I), which are indicators of As metabolism, increased with the urinary As level. Concentration and proportion of As(III) were high in the wild type of GSTP1 Ile105Val compared with the hetero type, and these trends were more pronounced in the higher As exposure group (>56 μg l(-1) creatinine in urine), but not in the lower exposure group. In the high As exposure group, As(III)/As(V) ratios in the urine of wild type of GSTP1 Ile105Val were significantly higher than those of the hetero type, while the opposite trend was observed for M/I. These results suggest that the excretion and metabolism of IA may depend on both the As exposure level and the GSTP1 Ile105Val genotype.

An update on ethnic differences in drug metabolism and toxicity from anti-cancer drugs

INTRODUCTION

Based on recent emerging evidence of inter-ethnic differences in drug response and toxicity, ethnic diversity in pharmacokinetics, pharmacogenomics and clinical outcomes are being increasingly investigated. Ultimately, this will promote improved understanding of inter-individual differences in the pharmacokinetics and tolerance of cytotoxic drugs.

AREAS COVERED

This article reviews potential explanations for the observed ethnic differences in treatment outcomes and provides clinical data to support this concept. A literature search was implemented on PubMed and PharmGKB to investigate the areas of ethnic differences in pharmacogenomics, pharmacogenetics and clinical outcomes of cancer therapies.

EXPERT OPINION

There has been a relative paucity of clinical evidence linking genetic polymorphisms of genes encoding drug-metabolizing enzymes to the pharmacokinetics, pharmacodynamics and tolerance of anti-cancer drugs. Future research should focus on studies using large sample sizes, in the hope that they will provide results of high clinical significance. Due to the potential for ethnic differences to impact on both toxicities and benefits of systemic cancer therapies, the development of new therapeutic agents should include patients from diverse geographical ancestries in each phase of drug development.

The role of glutathione S-transferase M1 and T1 gene polymorphisms and fruit and vegetable consumption in antioxidant parameters in healthy subjects

The correlation of glutathione S-transferase (GST) M1/T1 genetic polymorphisms with oxidative stress-related chronic diseases was proved recently. The aim of the present study was to investigate the association of GSTM1/T1 genetic polymorphisms with antioxidant biomarkers and consumption of fruits and vegetables (F&V) in healthy subjects. In this study, for conducting a 3 d dietary survey, 190 healthy adults were recruited. After DNA extraction, a multiple PCR method was used for GSTM1/T1 genotyping. A spectrophotometer method was applied for the determination of plasma total antioxidant capacity (T-AOC), vitamin C level and erythrocyte GST enzyme activity. A general linear model was used to compare the mean values of antioxidant parameters for different GSTM1/T1 genotypes and consumption of F&V. Polymorphisms of GSTM1/T1 had no effects on plasma T-AOC and vitamin C levels. Deletion of the GSTM1 gene decreased the erythrocyte GST activity. There was correlation between plasma T-AOC and consumption of F&V in the GSTM1− or GSTT1+ subjects. A similar pattern was evident for erythrocyte GST activity in the GSTM1− subjects. No association was found among consumption of F&V and GSTM1/T1 genotypes and plasma vitamin C level. Different consumption of F&V had no impact on plasma T-AOC and vitamin C levels in the GSTM1−/GSTT1+ or GSTM1−/GSTT1− subjects. The erythrocyte GST activity was more sensitive to consumption of F&V in the individuals with the GSTM1−/GSTT1+ genotype. Association was found among GSTM1/T1 genotypes, antioxidant parameters and consumption of F&V. Large-scale and multiple ethnic studies are needed to further evaluate the relationship.

Relationship between oxidative stress, glutathione S-transferase polymorphisms and hydroxyurea treatment in sickle cell anemia

This study evaluated the oxidative stress and antioxidant capacity markers in sickle cell anemia (SCA) patients with and without treatment with hydroxyurea. We assessed GSTT1, GSTM1 and GSTP1 polymorphisms in patients and a control group. The study groups were composed of 48 subjects without hemoglobinopathies and 28 SCA patients, 13 treated with HU [SCA (+HU)], and 15 SCA patients not treated with HU [SCA (-HU)]. We observed a significant difference for GSTP1 polymorphisms in SCA patients with the V/V genotype that showed higher glutathione (GSH) and Trolox equivalent antioxidant capacity (TEAC) (p=0.0445 and p=0.0360), respectively, compared with the I/I genotype. HU use was associated with a 35.2% decrease in the lipid peroxidation levels of the SCA (+HU) group (p<0.0001). Moreover, the SCA (+HU) group showed higher TEAC as compared to the control group (p=0.002). We did not find any significant difference in glutathione-S-transferase (GST) activity between the groups (p=0.76), but the catalase (CAT) activity was about 17% and 30% decreased in the SCA (+HU) and SCA (-HU) groups, respectively (p<0.00001). Whereas the plasma GSH levels were ~2 times higher in the SCA patients than the control group (p=0.0005). HU use has contributed to higher CAT activity and TEAC, and lower lipid peroxidation in patients under treatment. These findings may explain the influence of HU in ameliorating oxidative stress on SCA subjects.

Association of glutathione S-transferase M1 and T1 gene polymorphism with oxidative stress in diabetic and nondiabetic chronic kidney disease

BACKGROUND AND OBJECTIVE

Glutathione S-transferases (GSTs) belong to a family of ubiquitous and multifunctional enzymes that work as one of the endogenous antioxidants in our body. This study was designed to look into the association of GST polymorphism with oxidative stress in both diabetic and nondiabetic chronic kidney disease (CKD).

DESIGN AND METHODS

Three groups of patients (50 in each): diabetics without CKD (DM), diabetic CKD (DM-CKD), and nondiabetic CKD (NDM-CKD) and 50 age- and sex-matched healthy controls were recruited. Genotyping was done for GSTM1 and GSTT1 genes using a multiplex polymerase chain reaction. Serum GST and malondialdehyde (MDA) as a marker of oxidative stress were measured spectrophotometrically.

RESULTS

Based on genotyping, subjects were categorized as GSTM1+/GSTT1+, GSTM1-/GSTT1+, GSTM1+/GSTT1-, and GSTM1-/GSTT1-. Serum GST levels were lower among subjects with deletion in one/both GST genes, whereas MDA levels were found to be correspondingly raised. A negative correlation for MDA versus GST levels was observed among genotypes with one/both gene deletions. Presence of GSTM1+/GSTT1- and GSTM1-/GSTT1- was significantly higher among patients with CKD in both diabetics and nondiabetics.

INTERPRETATIONS AND CONCLUSIONS

GSTM1 and GSTT1 deletions singly or together were associated with lower GST levels and higher oxidative stress in both diabetic and nondiabetic CKD. Interestingly, GSTT1 deletion appears to be associated with both diabetic and nondiabetic CKD irrespective of the GSTM1 status.

Potential risk modifications of GSTT1, GSTM1 and GSTP1 (glutathione-S-transferases) variants and their association to CAD in patients with type-2 diabetes

BACKGROUND

Type-2 diabetes mellitus (T2DM) is a major risk factor for coronary artery disease (CAD) resulting in high morbidity and mortality. Glutathione S-transferases (GSTM1, GSTT1 and GSTP1) are known for their broad range of detoxification and in the metabolism of xenobiotics. Recent studies revealed the relationship of GSTs variants with T2DM and CAD. In this case-control study we ascertained the association of GSTs variants in association with the development of CAD in patients with T2DM.

METHODS

From the Southern part of India, we enrolled 222 T2DM patients, 290 T2DM patients with CAD and 270 healthy controls matched for age, sex and origin. Serum lipid profiles were measured and DNA was extracted from the blood samples. Multiplex PCR for GSTM1/T1 (null polymorphism) and PCR-RFLP for GSTP1 (105 A>G), were performed for genotyping of study participants. Gene frequency and lipid profiles were statistically analyzed for disease association.

RESULTS

Regression analysis showed that, GSTM1-null genotype is associated with a 2-fold increase (OR=2.925; 95% CI=2.078-4.119; P<0.0001) and GSTT1-null genotype is associated with a 3-fold increase (OR=3.114; 95% CI=2.176-4.456; P<0.0001) to T2DM development. Ile/Val and Val/Val genotypes of GSTP1 also showed a significant risk for T2DM (OR=1.423, CI=1.041-1.946; P=0.027 and OR=1.829, CI=1.064-3.142; P=0.029). Increased odds ratio showed that GSTT1-null genotype had a moderately higher occurrence in T2DM-CAD patients (OR=1.918, 95% CI=1.144-3.214; P=0.014) than T2DM patients without CAD. The level of HDL has significantly decreased in GSTT1-present than in GSTT1-null genotype (43.50±4.10 vs. 45.20±3.90; P=0.004) when compared with control and T2DM patients. However, LDL level showed a significant increase in GSTT1-null than GSTT1-present genotype (108.70±16.90 vs. 102.20±12.60; P=0.005). Although the GSTM1-null polymorphism showed no correlation with lipid profiles among T2DM and T2DM with CAD patients, GSTT1-null polymorphism attained a statistical significance for the level of LDL (127±28.20 vs. 134±29.10; P=0.039) and triglycerides in T2DM with CAD patients (182.10±21.10 vs. 191.20±24.10; P=0.018).

CONCLUSION

Our work concludes that GSTM1, GSTT1 and GSTP1 variants might contribute to the development of T2DM and GSTT1 variant alone is involved in the development of T2DM associated CAD complications in the South Indian population.

Lack of association of genetic polymorphisms of angiotensin-converting enzyme gene I/D and glutathione-S-transferase enzyme T1 and M1 with retinopathy of prematures

One of the most frequently observed causes of blindness in infancy is the pathogenesis known as retinopathy of prematurity (ROP). Angiotensin-converting enzyme (ACE) is a vital enzyme in the renin-angiotensin-aldosterone system; it is involved in the development of cardiovascular system diseases linked to I/D polymorphism of the ACE gene. Glutathione-S-transferase enzyme (GST) is one of the most important regulating components of the antioxidant system; there are indications that certain polymorphisms of GST genes (GSTT1, GSTM1), especially the null genotypes, increase the tendency for oxidative stress diseases. We investigated a possible correlation between ACE gene I/D and GSTT1 and GSTM1 gene polymorphisms in 56 prematures suffering from ROP and a control group composed of 48 prematures without ROP in a hospital in Turkey. PCR was used to detect the ACE I/D, GSTT1 and GSTM1 gene polymorphisms. Genotype was determined based on bands formed on agarose gel electrophoresis. We found no significant differences in genotype frequency of the ACE I/D, GSTT1 and GSTM1 genes between normal subjects and patients with ROP. Our results do not support an association of ACE I/D, GSTT1 and GSTM1 gene polymorphisms with risk for ROP.

Exposure, metabolism, and health effects of arsenic in residents from arsenic-contaminated groundwater areas of Vietnam and Cambodia: a review

In this review, we summarize the current knowledge on exposure, metabolism, and health effects of arsenic (As) in residents from As-contaminated groundwater areas of Vietnam and Cambodia based on our findings from 2000 and other studies. The health effects of As in humans include severe gastrointestinal disorders, hepatic and renal failure, cardiovascular disturbances, skin pigmentation, hyperkeratosis, and cancers in the lung, bladder, liver, kidney, and skin. Arsenic contamination in groundwater is widely present at Vietnam and Cambodia and the highest As levels are frequently found in groundwater from Cambodia. Sand filter system can reduce As concentration in raw groundwater. The results of hair and urine analyses indicate that residents from these As-contaminated areas are exposed to As. In general, sex, age, body mass index, and As exposure level are significantly associated with As metabolism. Genetic polymorphisms in arsenic (+III) methyltransferase and glutathione-S-transferase isoforms may be influenced As metabolism and accumulation in a Vietnamese population. It is suggested oxidative DNA damage is caused by exposure to As in groundwater from residents in Cambodia. An epidemiologic study on an association of As exposure with human health effects is required in these areas.

Association analysis of GSTT1, GSTM1 genotype polymorphisms and serum total GST activity with ischemic stroke risk

Oxidative stress plays a major role in pathogenesis of atherosclerosis which is responsible for stroke. Glutathione S-transferases (GSTs) detoxify metabolites produced by oxidative stress within the cell and protect the cells against injury. This study aimed to investigate the association of polymorphisms in GSTT1, GSTM1 genes and GST activity with ischemic stroke risk. Patients had almost the same GST activity as that of controls. No significant differences were found between patients and controls in terms of GSTT1 null, GSTM1 null and GSTT1/GSTM1 double null genotype frequencies. Besides, both patients and controls with double GSTT1/GSTM1 null genotypes had the lowest serum GST activities. Compared to the present genotypes, GSTT1 null (OR = 4.888; P = 0.006) and GSTM1 null (OR = 2.383; P = 0.011) genotype groups contained relatively more hypertensive stroke patients. This study showed that GSTT1 and GSTM1 null genotypes, together with hypertension, may play a significant role in the pathogenesis of ischemic stroke.

Association analysis of GSTT1, GSTM1 genotype polymorphisms and serum total GST activity with ischemic stroke risk

Oxidative stress plays a major role in pathogenesis of atherosclerosis which is responsible for stroke. Glutathione S-transferases (GSTs) detoxify metabolites produced by oxidative stress within the cell and protect the cells against injury. This study aimed to investigate the association of polymorphisms in GSTT1, GSTM1 genes and GST activity with ischemic stroke risk. Patients had almost the same GST activity as that of controls. No significant differences were found between patients and controls in terms of GSTT1 null, GSTM1 null and GSTT1/GSTM1 double null genotype frequencies. Besides, both patients and controls with double GSTT1/GSTM1 null genotypes had the lowest serum GST activities. Compared to the present genotypes, GSTT1 null (OR = 4.888; P = 0.006) and GSTM1 null (OR = 2.383; P = 0.011) genotype groups contained relatively more hypertensive stroke patients. This study showed that GSTT1 and GSTM1 null genotypes, together with hypertension, may play a significant role in the pathogenesis of ischemic stroke.

Lack of Association between Glutathione S-Transferase-M1, -T1, and -P1 Polymorphisms and Olanzapine-Induced Weight Gain in Korean Schizophrenic Patients

OBJECTIVE

Oxidative stress may be an important pathogenic mechanism in the obesity and metabolic syndrome. The aims of this study was to assess the possible association between the oxidative stress related Glutathione S-Transferase genes (GST-M1, GST-T1, and GST-P1) variants and the olanzapine-induced weight gain in Korean schizophrenic patients.

METHODS

We categorized 78 schizophrenic patients into two groups the more than 7% weight gain from baseline (weight gain >/=7%) and the less weight gain (weight gain <7%) groups according to weight change between before and after long-term olanzapine treatment (440+/-288 days). All participants were genotyped for the GST-M1, GST-T1 and GST-P1 genes. Differences in allele frequencies between cohorts with different body weight changes were evaluated by a chi-square analysis and Fisher's exact test. The multifactor dimensionality reduction (MDR) approach was used to analyze gene-gene interactions.

RESULTS

Mean body weight gain was 5.42 kg. There was no difference in the null genotype distribution of GST-M1 and -T1 between subjects with body weight gain >/=7% compared to subjects with body weight gain <7% (p>0.05). No significant difference in GST-P1 genotype and allele frequencies were observed between the groups (p>0.05). MDR analysis did not show a significant interaction between the three GST gene variants and susceptibility to weight gain (p>0.05).

CONCLUSION

These findings do not support a relationship between the genetic variants of three GST genes (GST-M1, -T1 and -P1) and weight gain in Korean schizophrenic patients receiving olanzapine treatment.

Association of glutathione-S-transferase polymorphisms with atopic dermatitis risk in preschool age children

BACKGROUND

Glutathione S-transferase (GST) enzymes are critical for detoxifying reactive oxygen species (ROS) and their products which have been implicated in the pathology of inflammatory diseases such as atopic dermatitis (AD).

METHODS

We investigated the effects of genetic polymorphisms of GST on the risk of AD in preschool age children. Biomarkers for oxidative stress were also evaluated with respect to GST genotype.

RESULTS

The GSTP1 Val105 allele was significantly associated with an increased risk of AD [odds ratio (OR)=1.62, p<0.05]. The combination of the GSTP1 Val105 allele and the GSTT1 null genotype further increased this risk by 2.3-fold (p<0.01). No association was observed for the GSTM1 null or GSTT1 null genotype alone. In children with AD, blood total antioxidant capacity was significantly less (p<0.001), while malondialdehyde was higher (p=0.12). Children with the GSTP1 Val105 allele had significantly lower concentrations of erythrocyte glutathione compared to GSTP1 ILE/ILE homozygotes (P=0.03).

CONCLUSIONS

Our study suggests that the GSTP1 Val105 allele is an important determinant of susceptibility to AD in preschool age children and increased oxidative stress may play a role in the pathogenesis of AD.

Polymorphisms of GSTT1 and GSTM1 and increased micronucleus frequencies in peripheral blood lymphocytes in residents at an e-waste dismantling site in China

In the present study, we investigated whether genetic polymorphisms of metabolic enzymes in an exposed population were associated with genotoxic effects of the pollutants from e-waste in 58 subjects (the exposed) resided in a typical e-waste recycling site and 80 subjects (the controls) from a village away from the recycling site. Effects of genetic polymorphisms of glutathione S-transferases (GSTs) (GSTT1 and GSTM1) on the frequency of micronucleated binucleated cells (MNed BNC) in peripheral blood lymphocytes were evaluated. GSTM1 and GSTT1 were typed using PCR-restriction fragment length polymorphism methods. Cytogenetic alterations were evaluated using the cytokinesis-block micronucleus assay. The MNed BNC frequency was significantly higher in the exposed group (median: 4.0 per thousand, IQR: 2.0-7.0 per thousand) than in the control group (median: 1.0 per thousand, IQR: 0.0-2.0 per thousand, P < 0.01 for both comparisons); sera GST activities were also higher in the exposed subjects with either non-null GSTT1 (mean +/- SD: 20.27 +/- 6.43) or non-null GSTM1 (mean +/- SD: 19.71 +/- 4.89) than in the controls (mean +/- SD: 18.79 +/- 4.91 and 19.34 +/- 6.42, respectively, P < 0.05 for both). Although the increased MNed BNC frequencies among the exposed group may be associated with the co-exposure of various chemical pollutants in the environment, there was no statistical evidence of an association between GSTs genotypes and frequencies of micronuclei in the study population. Because this study size was small, the mechanism of genotoxic effects caused by exposure to e-waste needs to be further validated in larger studies.

Functional alterations in the glutathione S-transferase family associated with enhanced occurrence of esophageal carcinoma in China

Glutathione S-transferases (GST) belong to a superfamily of phase II enzymes believed to be associated with enhanced frequency of esophageal carcinoma. This study was performed to evaluate whether the GST family was associated with susceptibility to esophageal carcinoma in China. Ninety-seven patients with newly diagnosed, untreated esophageal squamous-cell carcinoma (ESCC) and 97 healthy controls matched in age, gender, and residence were recruited in this community-based case-control study. Null genotypes of GSTM1 and GSTT1 were determined by multiplex polymerase chain reaction (PCR) technique. Ile105Val polymorphism in the fifth exon, mRNA level, CpG island hypermethylation of promoter, and protein levels of GSTP1 gene were measured with peripheral blood mononuclear cell (PBMC) by PCR-restriction fragment length polymorphism (PCR-RFLP) techniques, quantitative real-time reverse transcription PCR, methylation-specific PCR (MSP), and Western blotting, respectively. The results showed that GSTM1 null genotype and GSTT1 null genotype were significantly associated with increased risk for esophageal cancer in Chinese population. Compared with the control, the relative expression levels of mRNA were significantly reduced in ESCC patients. The conditional logistic regression analysis demonstrated that increased risk for esophageal cancer was associated with CpG island hypermethylation of promoter of GSTP1 gene. GSTP1 protein levels also showed significant decrease in ESCC when adjusted for age, gender, smoking status, and alcohol use. An individual with GSTM1 or GSTT1 null genotype may thus be more susceptible to esophageal cancer development. Reduced expression in mRNA and protein levels were the main manifestations noted in aberrant function of GSTP1 gene. Data thus suggest that the CpG island hypermethylation of promoter gene may serve as a useful biomarker for early diagnosis of esophageal carcinoma development.

The role of glutathione S- transferase M1 and T1 gene polymorphisms and oxidative stress-related parameters in Egyptian patients with essential hypertension

BACKGROUND

Essential hypertension is a complex, multifactorial, polygenic disease in which the underlying genetic components remain unknown. Glutathione S-transferase (GST) enzyme is involved in detoxification of reactive oxygen species. This study aimed to investigate GSTM1 and GSTT1 gene polymorphisms in Egyptian essential hypertensive patients and their relationship with oxidative stress-related parameters.

METHODS

The study included 40 newly-diagnosed, untreated, essential hypertensive patients and 40 normotensive subjects. Plasma levels of malondialdehyde (MDA), and nitrate/nitrite and erythrocyte reduced glutathione (GSH), activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and glutathione S-transferase (GST) were measured. Genotyping for GSTM1 and GSTT1 was performed.

RESULTS

The frequency of GSTM1+ve/GSTT1+ve in hypertensives (5%) was lower than in normotensives (37.5%).The frequency of GSTM1-ve/GSTT1-ve was elevated in hypertensives (35%) as compared to normotensives (7.5%). Plasma MDA was higher and nitrate/nitrite was lower in hypertensives than in normotensives. Erythrocyte GSH, activities of CAT, SOD, GSH-Px, and GST of hypertensives were lower than normotensives. Moreover, GST activity was lower in subjects with GSTM1-ve/GSTT1-ve than in those with GSTM1+ve/GSTT1+ve. In hypertensives, both systolic and diastolic blood pressures were negatively correlated with activities of CAT, GSH-Px, and GST.

CONCLUSIONS

GSTM1-ve/GSTT1-ve is a potential genetic factor to predict development of essential hypertension and permit early therapeutic intervention. The significant association between blood pressure and oxidative stress-related parameters indicates the pathogenic role of oxidative stress in hypertension. Antioxidants could be useful in the management of essential hypertension to prevent progressive deterioration and target organ damage however, further studies involving long-term clinical trials may help to assess the efficacy of these therapeutic agents.

Glutathione-S-transferase M1 and T1 Genetic Polymorphisms and the Risk of Cataract Development: A Study in the Turkish Population

In this study, we aimed to determine the effects of genetic polymorphisms of glutathione-S-transferase M1 (GSTM1) and glutathione-S-transferase T1 (GSTT1) on risk of developing different subtypes of age-related cataract in the Turkish population. Using a multiplex polymerase chain reaction (PCR), GSTM1 and GSTT1 gene polymorphisms were analyzed in 195 patients with age-related cataract (75 patients with cortical, 53 with nuclear, 37 with posterior subcapsular, and 30 with mixed type) and in 136 patients of an otherwise healthy control group of similar age. GSTM1 null genotype had a significant association with the development of cataract in female subjects (p < 0.0029; OR, 2.98; 95% CI, 1.41-6.34). This relationship in female subjects was only in nuclear and mixed types cataract cases (p < 0.002; OR, 4.58; 95% CI, 1.67-12.78 and p < 0.03, respectively). There was also a statistically significant association between the combination of GSTM1-null and GSTT1-positive genotypes and the risk of cataract development in female subjects (p = 0.01; OR = 2.87; 95% CI = 1.25-6.69). Stratification by the subtypes revealed that this association was only in nuclear type cataract (p = 0.001; OR, 3.92; 95% CI, 1.34-11.71). GSTM1-null genotype or combination of the GSTM1-null and GSTT1-positive genotypes in females may be associated with increased risk of cataract development in the Turkish population.

Association study between glutathione S-transferase GST-M1, GST-T1, and GST-P1 polymorphisms and tardive dyskinesia

OBJECTIVES

Data from several studies suggest that oxidative stress may play a role in the pathophysiology of tardive dyskinesia (TD). Glutathione S-transferase (GST) enzymes play important roles in protecting cells against oxidative stress. In the present study, we investigated the hypothesis that polymorphisms in genes for these detoxifying enzymes can influence susceptibility to TD in patients with schizophrenia.

METHODS

The GST-M1, GST-T1, and GST-P1 loci were analyzed by polymerase chain reaction (PCR)-based methods in 83 schizophrenic patients with TD and 126 schizophrenic without TD who were matched for antipsychotic drug exposure and other relevant variables. The multifactor dimensionality reduction (MDR) approach was used to analyze gene-gene interactions.

RESULTS

There were no significant differences in the distributions of the GST-M1, GST-T1, and GST-P1 genotypes between the TD and non-TD groups (p > 0.05). However, in comparison of the severity of TD among genotypes using Poisson regression showed that Ile/Ile genotype of GST-P1 had higher AIMS score compared to Ile/Val + Val/Val genotypes (X(2) = 7.13, p = 0.008). MDR analysis did not show a significant interaction between the three GST gene variants and susceptibility to TD (p > 0.05).

CONCLUSIONS

These results suggest that GST gene polymorphisms do not confer increased susceptibility to TD in patients with schizophrenia but TD severity might be related with GST-P1 variants.

Genetic Polymorphism in Glutathione Transferases (GST): Population distribution of GSTM1, T1, and P1 conjugating activity

Glutathione transferases (GST) catalyze the conjugation of glutathione (GSH) with electrophiles, many of which may otherwise interact with protein or DNA. In select cases such as halogenated solvents, GST-mediated conjugation may lead to a more toxic or mutagenic metabolite. Polymorphisms that exert substantial effects on GST function were noted in human populations for several isozymes. This analysis focuses on three well-characterized isozymes, GSTM1, T1, and P1, in which polymorphisms were extensively studied with respect to DNA adducts and cancer in molecular epidemiologic studies. The current review and analysis focused upon how polymorphisms in these GST contributed to population variability in GST function. The first step in developing this review was to characterize the influence of genotype on phenotype (enzyme function) and the frequency of the polymorphisms across major population groups for all three GST. This information was then incorporated into Monte Carlo simulations to develop population distributions of enzyme function. These simulations were run separately for GSTM1, T1, and P1, and also for the combination of these isozymes, to assess the possibility of overlapping substrate specificity. Monte Carlo simulations indicated large interindividual variability for GSTM1 and T1 due to the presence of the null (zero activity) genotype, which is common in all populations studied. Even for GSTM1 or T1 non-null individuals, there was considerable interindividual variability with a bimodal distribution of enzyme activity evident. GSTP1 polymorphisms are associated with somewhat less variability due to the absence of null genotypes. However, in all cases simulated, the estimated variability is sufficiently large to warrant consideration of GST function distributions in assessments involving GST-mediated activation or detoxification of xenobiotics. Ideally, such assessments would involve physiologically based toxicokinetic (PBTK) modeling to assess population variability in internal dose.

Association between GSTP1 gene polymorphism and serum α-GST concentrations undergoing sevoflurane anaesthesia

BACKGROUND AND OBJECTIVES

The measurement of alpha-glutathione-S-transferase enzyme is one of the most sensitive indicators of hepatocellular function. Variation in the glutathione-S-transferase P1 gene clusters has been intensively investigated and polymorphism has been described. The aim of the study was to assess whether an association exists between glutathione-S-transferase P1 gene polymorphism and serum alpha-glutathione-S-transferase concentrations for the first postoperative day in patients who underwent anaesthesia with sevoflurane.

METHODS

In all, 54 unrelated patients were enrolled in this study. Anaesthesia was induced with thiopental and fentanyl. Vecuronium was used for neuromuscular relaxation before endotracheal intubation. Anaesthesia was maintained with sevoflurane in a gas mixture containing 50% nitrous oxide in oxygen. Peripheral venous blood samples to determine serum alpha-glutathione-S-transferase concentrations were collected before induction (T1), at the end of anaesthesia (T2) and at 24-h postoperatively (T3). Enzyme-linked immunosorbent assay (ELISA) immunoassay was used to measure alpha-glutathione-S-transferase levels. Genomic DNA was isolated from serum samples using a genomic DNA purification kit. In order to detect the variants of glutathione-S-transferase P1, polymerase chain reaction-restriction fragment length polymorphism analysis was employed.

RESULTS

Early postoperative serum alpha-glutathione-S-transferase levels for all patients were significantly increased when compared with preanaesthetic and 24-h postoperatively (P 0.05).

CONCLUSIONS

Although alpha-glutathione-S-transferase levels were elevated in all patients after sevoflurane anaesthesia, levels remained high at 24 h in patients with glutathione-S-transferase P1 Ile105Val genotypes compared to controls.

Relationship between glutathione S-transferase gene polymorphisms and enzyme activity in Hong Kong Chinese asthmatics

BACKGROUND

Asthma is a disease associated with oxidative stress. The glutathione S-transferases (GST) are a group of enzymes that protect cells from oxidative stress. Functional genetic polymorphisms of GST genes (GSTT1, GSTM1 and GSTP1) have previously been reported.

OBJECTIVE

To investigate the association of GST gene polymorphisms and its enzyme activity with the risk of asthma in Hong Kong Chinese adults.

METHODS

An age- and smoking status-matched case-control study was carried out on 315 patients with asthma and 315 healthy controls. Genotyping was carried out on genomic DNA using the PCR and/or restriction fragment length polymorphism (PCR-RFLP). Plasma GST activity was measured by fluorometric assay.

RESULTS

The distribution of various genotypes or alleles of the GSTT1, GSTM1 and GSTP1 was not significantly different between patients with asthma and healthy controls. The GSTM1 null genotype was found to be protective from the development of asthma in atopic subjects (odds ratios 0.55, 95% confidence interval 0.34-0.90; P=0.017). However, there was no association between GSTT1 and GSTM1 null genotypes and enzyme activity. GSTP1 codon 105 Val variants led to reduced plasma GST activity in healthy controls. Asthma patients had elevated plasma GST activity compared with healthy controls irrespective of their genotypes (P<0.001).

CONCLUSION

Our data suggest that among atopic subjects, the GSTM1 null genotype is associated with a decreased risk for asthma despite increased level of plasma GST activity in asthma, but it could not distinguish whether this increase is a potentially protective compensatory effect or a pathogenic factor.

Glutathione S-transferase M1 and P1 polymorphisms and risk of breast cancer and fibrocystic breast conditions in Chinese women

Enzymes encoded by the glutathione S-tranferase mu 1 (GSTM1) and pi 1 (GSTP1) genes, which are expressed in breast tissue, catalyze the detoxification of endogenous and exogenous electrophiles. Reduced enzyme activity, due to carriage of the GSTM1 deletion or the GSTP1 Ile105Val Val allele, may therefore affect susceptibility to breast cancer and related conditions. In a case-control study of Chinese women, we examined whether these polymorphisms were associated with risk of breast cancer and fibrocystic breast conditions. Women diagnosed with breast cancer (n=615) or fibrocystic breast conditions (n=467) were compared to women without clinical breast disease (n=878). We also examined whether these associations differed by menopausal status or by presence of proliferation in the extra-tumoral epithelium among women with breast cancer and in lesions among women with fibrocystic conditions. No overall association of either GST polymorphism with risk of breast cancer or fibrocystic breast conditions was observed. There was some evidence of slightly elevated cancer risk associated with carriage of the GSTM1 null genotype and at least one GSTP1 105-Val allele (OR=1.33, 95% CI, 0.99-1.80), compared to carriage of the GSTM1 non-null and GSTP1 Ile/Ile genotypes. This relationship was stronger in women who had breast cancer with extra-tumoral tissue proliferation (OR=1.77, 95% CI, 1.03-3.04). Our results suggest that GSTM1 and GSTP1 genotypes do not individually influence susceptibility to breast cancer or fibrocystic breast conditions. The observed increased risk of breast cancer associated with joint carriage of the GSTM1 null genotype and GSTP1 105-Val allele needs confirmation in other studies.