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

The Impact of Genetic Polymorphisms in Glutamate-Cysteine Ligase, a Key Enzyme of Glutathione Biosynthesis, on Ischemic Stroke Risk and Brain Infarct Size

The purpose of this pilot study was to explore whether polymorphisms in genes encoding the catalytic (GCLC) and modifier (GCLM) subunits of glutamate-cysteine ligase, a rate-limiting enzyme in glutathione synthesis, play a role in the development of ischemic stroke (IS) and the extent of brain damage. A total of 1288 unrelated Russians, including 600 IS patients and 688 age- and sex-matched healthy subjects, were enrolled for the study. Nine common single nucleotide polymorphisms (SNPs) of the GCLC and GCLM genes were genotyped using the MassArray-4 system. SNP rs2301022 of GCLM was strongly associated with a decreased risk of ischemic stroke regardless of sex and age (OR = 0.39, 95%CI 0.24−0.62, p < 0.0001). Two common haplotypes of GCLM possessed protective effects against ischemic stroke risk (p < 0.01), but exclusively in nonsmoker patients. Infarct size was increased by polymorphisms rs636933 and rs761142 of GCLC. The mbmdr method enabled identifying epistatic interactions of GCLC and GCLM gene polymorphisms with known IS susceptibility genes that, along with environmental risk factors, jointly contribute to the disease risk and brain infarct size. Understanding the impact of genes and environmental factors on glutathione metabolism will allow the development of effective strategies for the treatment of ischemic stroke and disease prevention.

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.

GSTM1 Modulates Expression of Endothelial Adhesion Molecules in Uremic Milieu

Deletion polymorphism of glutathione S-transferase M1 (GSTM1), a phase II detoxification and antioxidant enzyme, increases susceptibility to end-stage renal disease (ESRD) as well as the development of cardiovascular diseases (CVD) among ESRD patients and leads to their shorter cardiovascular survival. The mechanisms by which GSTM1 downregulation contributes to oxidative stress and inflammation in endothelial cells in uremic conditions have not been investigated so far. Therefore, the aim of the present study was to elucidate the effects of GSTM1 knockdown on oxidative stress and expression of a panel of inflammatory markers in human umbilical vein endothelial cells (HUVECs) exposed to uremic serum. Additionally, we aimed to discern whether GSTM1-null genotype is associated with serum levels of adhesion molecules in ESRD patients. HUVECs treated with uremic serum exhibited impaired redox balance characterized by enhanced lipid peroxidation and decreased antioxidant enzyme activities, independently of the GSTM1 knockdown. In response to uremic injury, HUVECs exhibited alteration in the expression of a series of inflammatory cytokines including retinol-binding protein 4 (RBP4), regulated on activation, normal T cell expressed and secreted (RANTES), C-reactive protein (CRP), angiogenin, dickkopf-1 (Dkk-1), and platelet factor 4 (PF4). GSTM1 knockdown in HUVECs showed upregulation of monocyte chemoattractant protein-1 (MCP-1), a cytokine involved in the regulation of monocyte migration and adhesion. These cells also have shown upregulated intracellular and vascular cell adhesion molecules (ICAM-1 and VCAM-1). In accordance with these findings, the levels of serum ICAM-1 and VCAM-1 (sICAM-1 and sVCAM-1) were increased in ESRD patients lacking GSTM1, in comparison with patients with the GSTM1-active genotype. Based on these results, it may be concluded that incubation of endothelial cells in uremic serum induces redox imbalance accompanied with altered expression of a series of cytokines involved in arteriosclerosis and atherosclerosis. The association of GSTM1 downregulation with the altered expression of adhesion molecules might be at least partly responsible for the increased susceptibility of ESRD patients to CVD.

GSTM1 Deletion Exaggerates Kidney Injury in Experimental Mouse Models and Confers the Protective Effect of Cruciferous Vegetables in Mice and Humans

BACKGROUND

GSTM1 encodes glutathione S-transferase μ-1 (GSTM1), which belongs to a superfamily of phase 2 antioxidant enzymes. The highly prevalent GSTM1 deletion variant is associated with kidney disease progression in human cohorts: the African American Study of Kidney Disease and Hypertension and the Atherosclerosis Risk in Communities (ARIC) Study.

METHODS

We generated a Gstm1 knockout mouse line to study its role in a CKD model (involving subtotal nephrectomy) and a hypertension model (induced by angiotensin II). We examined the effect of intake of cruciferous vegetables and GSTM1 genotypes on kidney disease in mice as well as in human ARIC study participants. We also examined the importance of superoxide in the mediating pathways and of hematopoietic GSTM1 on renal inflammation.

RESULTS

Gstm1 knockout mice displayed increased oxidative stress, kidney injury, and inflammation in both models. The central mechanism for kidney injury is likely mediated by oxidative stress, because treatment with Tempol, an superoxide dismutase mimetic, rescued kidney injury in knockout mice without lowering BP. Bone marrow crosstransplantation revealed that Gstm1 deletion in the parenchyma, and not in bone marrow-derived cells, drives renal inflammation. Furthermore, supplementation with cruciferous broccoli powder rich in the precursor to antioxidant-activating sulforaphane significantly ameliorated kidney injury in Gstm1 knockout, but not wild-type mice. Similarly, among humans (ARIC study participants), high consumption of cruciferous vegetables was associated with fewer kidney failure events compared with low consumption, but this association was observed primarily in participants homozygous for the GSTM1 deletion variant.

CONCLUSIONS

Our data support a role for the GSTM1 enzyme in the modulation of oxidative stress, inflammation, and protective metabolites in CKD.

The GSTM1 and GSTT1 Null Genotypes Increase the Risk for Type 2 Diabetes Mellitus and the Subsequent Development of Diabetic Complications: A Meta-analysis

BACKGROUND

Studies pertaining to association of GSTM1 and GSTT1 null genotypes with risk of T2DM and its complications were often inconclusive, thus spurring the present study.

METHODS

Meta-analysis of 25 studies for evaluating the role of GSTM1/GSTT1 null polymorphisms in determining the risk for T2DM and 17 studies for evaluating the role of GSTM1/GSTT1 null polymorphisms in development of T2DM related complications were conducted.

RESULTS

Our study revealed an association between GSTM1 and GSTT1 null polymorphism with T2DM (GSTM1; OR=1.37;95% CI =1.10-1.70 and GSTT1; OR=1.29;95% CI =1.04-1.61) with an amplified risk of 2.02 fold for combined GSTM1-GSTT1 null genotypes. Furthermore, the GSTT1 null (OR=1.56;95%CI=1.38-1.77) and combined GSTM1-GSTT1 null genotypes (OR=1.91;95%CI=1.25- 2.94) increased the risk for development of T2DM related complications, but not the GSTM1 null genotype. Stratified analyses based on ethnicity revealed GSTM1 and GSTT1 null genotypes increase the risk for T2DM in both Caucasians and Asians, with Asians showing much higher risk of T2DM complications than Caucasians for the same.

DISCUSSION

GSTM1, GSTT1 and combined GSTM1-GSTT1 null polymorphism may be associated with increased risk for T2DM; while GSTT1 and combined GSTM1-GSTT1 null polymorphism may increase the risk of subsequent development of T2DM complications with Asian population carrying an amplified risk for the polymorphism.

CONCLUSION

Thus GSTM1 and GSTT1 null genotypes increases the risk for Type 2 diabetes mellitus alone, in combination or with regards to ethnicity.

Glutathione S-Transferase M1 and T1 polymorphisms and hypertension risk: an updated meta-analysis

Recently, Glutathione S-transferase M1 (GSTM1), glutathione S-transferase T1 (GSTT1), and their interaction with hypertension risk have been focused on. However, the results of previous studies have been inconsistent. Hence, the present meta-analysis was performed to explore the association. Twenty-two case-control studies met the inclusion criteria for GSTM1 (including 3577 hypertension cases and 3784 controls), twenty-two for GSTT1 (including 3741 cases and 4444 controls), and nine for their combined effects (including 1073 cases and 781 controls). Pooled analyses on the association between GSTM1 present/null polymorphism and hypertension risk were observed to be insignificant in overall and subgroup analyses. The individual who carries the GSTT1 null-genotype had a statistically significant overall population (OR = 1.28, 95% CI: 1.03, 1.60), Indians (OR = 2.45, 95% CI: 1.08, 5.59), and hospital-based controls (OR = 1.53, 95% CI: 1.21, 1.94). For the GSTM1-GSTT1 interaction, we found that the GSTM1/GSTT1 double-null-genotype was significantly associated with hypertension risks (double-null vs. double-present: OR = 2.68, 95% CI: 1.06, 6.81). To summarize, this meta-analysis indicates that Indians with the GSTT1 null-genotype has a raised hypertension risks; the GSTM1 null/GSTT1 null-genotype is association with raised hypertension risks, while the GSTM1 null-genotype is not associated with hypertension risks. In addition, I² > 75% cannot be eliminated for GSTM1 in Indians or Asians, hence, it will be very important to explore the GSTM1 null-genotype and hypertension susceptibility in Indians and Asians for a large new sample, on population-based control study.

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.

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 Pi-Ile 105 Val Polymorphism and Susceptibility to T2DM in Population from Turabah Region of Saudi Arabia

Type 2 diabetes mellitus is characterized by chronic hyperglycemia and associated with oxidative stress resulting from accumulation of free radicals in body's tissues, which especially affects beta cells in pancreas and is an important factor in the development of diabetes and its complications. Glutathione S-transferases (GSTs) are a family of antioxidant enzymes that play important roles in decreasing ROS species and act as a kind of antioxidant defense. In a case-control study, we investigated the role of GSTP1 Ile105Val polymorphism in predisposition to T2DM in patients from Tarabah province, Saudi Arabia. The polymorphism was screened by PCR-RFLP in 90 T2DM patients and 87 healthy controls. The genotypes and alleles frequencies in cases and controls were assessed using Cochran-Armitage trend test and odds ratios (ORs), and 95 % confidence intervals (CIs) in different genetic models of inheritance were calculated. Our data indicate that G allele (Val) is associated with an increased risk for T2DM in this population in any combination (OR 4.101, 95 % CI 1.986-8.469, P = 0.00008). This indicates that individuals who are carriers for the mutant allele, either in homozygous (GG) or heterozygous (AG) state, are at fourfold higher risk for development of T2DM than other subjects in this population.

Antioxidant Potential of Vespa affinis L., a Traditional Edible Insect Species of North East India

Introduction

Elevated oxidative stress plays an important role in the pathogenesis of health disorders, like arthritis. Traditionally, Vespa affinis L., a common edible insect among many tribes in North-East India, is believed to have a beneficial role in extenuating health disorders, such as arthritis. The present study investigated the molecular mechanism underlying medicinal benefit of the Aqueous Extract of Vespa affinis L. (AEVA) against oxidative stress pathophysiology.

Methods

The free radical scavenging activities of AEVA were examined against DPPH, hydroxyl, and superoxide radicals and the effect on the activities of antioxidant enzyme (GST and CAT) was determined using both recombinant proteins and human plasma. The antioxidant potential of AEVA was again investigated using THP-1 monocytes.

Results

AEVA possesses a significant free radical scavenging activity as evident from the DPPH, superoxide, and hydroxyl radical scavenging assay. Incubation of AEVA (2.5, 5, 7.5, and 10 μg/μL) with the recombinant antioxidant enzymes, rGST and rCAT significantly increased the enzyme activities compared to those observed in corresponding enzyme alone or AEVA itself. AEVA supplementation (5, 7.5, and 10 μg/μL) also stimulates the activities of GST and CAT when incubated with human plasma. A cell culture study also confirmed the beneficial role of AEVA (0.8 and 1.2 μg/μL) which enhances the activities of GST and CAT, and also reduces the intercellular ROS production in monocytes treated with or without H₂O₂ and the effects are at par with what is observed in N-acetyl cysteine-treated cells.

Conclusion

The antioxidant potential of the aqueous extract of Vespa affinis L. may mediate its therapeutic activities in oxidative stress-associated health disorders.

The impact of detoxifying and repair gene polymorphisms on oxidative stress in ischemic stroke

Stroke is a multifactorial disease caused by the combination of certain risk factors and genetic factors. There are possible risk factors having important role in the pathogenesis of stroke. The most important environmental factors are cigarette smoking and oxidative stress which have different sources. GST (M1, T1, P1) have major roles in detoxification of the products of oxidative stress and they are polymorphic. DNA damages can also be repaired by repair enzymes such as OGG1 and XRCC1 which are highly polymorphic and have pivotal roles in repair systems. In the present study, we investigated that polymorphisms in genes involved in detoxification and DNA-repair pathways might modify the individual's risk for ischemic stroke. Furthermore, the products of oxidative stress and antioxidant capacity were measured and the impact of gene polymorphism on them was evaluated. Our data showed that OGG1 Ser326Cys and XRCC1 Arg399Gln gene polymorphisms had impacts on the development of stroke.

Glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) null polymorphisms and the risk of hypertension: a meta-analysis

BACKGROUND

Some studies have recently focused on the association between glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) null polymorphisms and hypertension; however, results have been inconsistent.

OBJECTIVE

In order to drive a more precise estimation, the present systematic review and meta-analysis is performed to investigate the relationship between the GSTM1 and GSTT1 null polymorphisms and hypertension.

METHODS

Eligible articles were identified by a search of several bibliographic databases for the period up to August 17, 2013. Odds ratios were pooled using either fixed-effects or random-effects models.

RESULTS

Regarding the GSTM1 null/present genotype, 14 case-control studies were eligible (2773 hypertension cases and 3189 controls). The meta-analysis revealed that it might present a small increased risk for hypertension, although the effect was not statistically significant (odd ratio (OR) = 1.16, 95% confidence interval (CI): 0.96, 1.40; P = 0.002, I2 = 59.8%). Further subgroup analysis by ethnicity and control source suggested that the association was still not significant. Thirteen case-control studies were eligible for GSTT1 (2497 hypertension cases and 3078 controls). No statistically significant association was observed between the GSTT1 null genotype and hypertension risk (OR = 1.14, 95% CI: 0.85, 1.53; P = 0.000, I2 = 80.3%). Furthermore, stratification by ethnicity and control source indicated no association between the GSTT1 null genotype and hypertension risk. We further confirmed the association by sensitivity analysis. No publication bias was detected.

CONCLUSION

This meta-analysis suggests that the GSTM1 and GSTT1 null polymorphisms are not associated with the risk of hypertension. Future large well-designed epidemiological studies with individual information, lifestyle factors, and environmental factors are warranted to validate the present findings.

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

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

Fibrinogen nitrotyrosination after ischemic stroke impairs thrombolysis and promotes neuronal death

Ischemic stroke is an acute vascular event that compromises neuronal viability, and identification of the pathophysiological mechanisms is critical for its correct management. Ischemia produces increased nitric oxide synthesis to recover blood flow but also induces a free radical burst. Nitric oxide and superoxide anion react to generate peroxynitrite that nitrates tyrosines. We found that fibrinogen nitrotyrosination was detected in plasma after the initiation of ischemic stroke in human patients. Electron microscopy and protein intrinsic fluorescence showed that in vitro nitrotyrosination of fibrinogen affected its structure. Thromboelastography showed that initially fibrinogen nitrotyrosination retarded clot formation but later made the clot more resistant to fibrinolysis. This result was independent of any effect on thrombin production. Immunofluorescence analysis of affected human brain areas also showed that both fibrinogen and nitrotyrosinated fibrinogen spread into the brain parenchyma after ischemic stroke. Therefore, we assayed the toxicity of fibrinogen and nitrotyrosinated fibrinogen in a human neuroblastoma cell line. For that purpose we measured the activity of caspase-3, a key enzyme in the apoptotic pathway, and cell survival. We found that nitrotyrosinated fibrinogen induced higher activation of caspase 3. Accordingly, cell survival assays showed a more neurotoxic effect of nitrotyrosinated fibrinogen at all concentrations tested. In summary, nitrotyrosinated fibrinogen would be of pathophysiological interest in ischemic stroke due to both its impact on hemostasis - it impairs thrombolysis, the main target in stroke treatments - and its neurotoxicity that would contribute to the death of the brain tissue surrounding the infarcted area.

Expressions of oxidative stress-related genes and antioxidant enzyme activities in Mytilus galloprovincialis (Bivalvia, Mollusca) exposed to hypoxia

Background

In this study, we investigated transcription and enzyme level responses of mussels Mytilus galloprovincialis exposed to hypoxic conditions. Genes for catalase (CAT), cytochrome P450, glutathione S-transferase (GST), metallothionein, superoxide dismutase (SOD), cytochrome c oxidase subunit 1 (COX-1), and NADH dehydrogenase subunit 2 were selected for study. Transcriptional changes were investigated in mussels exposed to hypoxia for 24 and 48 h and were compared to changes in control mussels maintained at normal oxygen levels. Activities of CAT, GST, and SOD enzymes, and lipid peroxidation (LPO) were also investigated in mussels following exposure to hypoxia for 24, 48, and 72 h.

Results

Relative to the control group, the CAT activity decreased in all hypoxia treatments, while the activity of GST significantly increased in mussels exposed to hypoxia for 24 and 48 h, but decreased in those exposed for 72 h. The LPO levels were significantly higher in mussels in the 24- and 48-h hypoxia treatments than those in the control mussels, but there was no significant change in the SOD activities among all hypoxia treatments. Messenger RNA levels for the CAT, cytochrome P450, GST, metallothionein, and SOD genes were not significantly affected by hypoxic conditions for 48 h, but the expressions of the COX-1 and NADH dehydrogenase subunit 2 genes were significantly repressed in mussels in both the 24- and 48-h exposure treatments.

Conclusions

These results demonstrate the transcriptional stability and changes among several genes related to oxidative stress under oxygen-depletion conditions in M. galloprovincialis and provide useful information about the modulation of antioxidant enzyme activities induced by hypoxia in a marine animal.

Interaction between glutathione S-transferase variants, maternal smoking and childhood wheezing changes with age

BACKGROUND

Maternal smoking increases the risk of respiratory symptoms in children. Glutathione S-transferases (GSTs) detoxify xenobiotics from tobacco smoke, and functional polymorphism in GST gene(s) could predispose children to the detrimental effects of maternal smoking. Our objective was to investigate interactions between GST variants and maternal smoking in relation to the development of wheezing during childhood and whether any such interaction changes with time.

METHODS

In a population-based birth cohort, we assessed maternal smoking and current wheeze at five time points during the first 11 yr of life. DNA was genotyped for GSTP1, GSTM1 and GSTT1 (n = 807). Longitudinal analyses were performed using generalized estimating equations.

RESULTS

During early childhood, children whose mothers smoked were more likely to wheeze, with the strongest association observed at age 3 yr (p = 0.006). In a longitudinal model, children with GSTP1 AA and AG genotypes had significantly higher risk of wheeze compared with GG homozygotes. We observed a significant interaction between GSTP1 and maternal smoking where the risk of infantile wheezing was significantly increased in AA homozygotes, but only if their mothers smoked (OR 2.59, [1.08-6.21], p(int) = 0.03). Furthermore, amongst AA carriers, there was a significant interaction between child's age and maternal smoking, with the effect of maternal smoking on the risk of wheeze significantly diminishing with age (p(int) = 0.05); no such findings were observed for GSTM1 and GSTT1.

CONCLUSIONS

Children with AA genotype for GSTP1 are at increased risk of early-life wheezing if their mothers smoke, but the effect of maternal smoking on wheezing diminishes with time.

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

BACKGROUND AND OBJECTIVE

The genetic variants of xenobiotic-metabolizing enzymes, such as those encoded by glutathione-S-transferase (GST) genes, may be associated with the risk of coronary artery disease (CAD). To investigate the genetic factors for CAD, we examined the GSTM1, GSTT1, GSTP1, and GSTA1 genotypes in a CAD cohort in Taiwan.

METHODS

Our study included 458 CAD participants and 209 control participants who received coronary angiography to assess CAD. The severity of CAD was defined as the number of coronary vessels with 50% or greater stenosis. Sequence variation of the GSTM1 and GSTT1 genes was determined using a polymerase chain reaction (PCR). The GSTP1 (Ile105Val), and GSTA1 (-69C>T) genetic variants were identified using a combination of PCR and restriction fragment length polymorphism analysis. Logistic regression analysis was used to calculate the odds ratios (ORs) and 95% confidence intervals.

RESULTS

Among the GST genetic variants examined, the GSTT1 null genotype was more prevalent in CAD participants with 3 stenosed vessels than in control participants (OR=1.64, P=.02). This association was no longer observed after adjusting for age, sex, smoking, alcohol use, diabetes mellitus, and serum levels of total cholesterol and high-density lipoprotein cholesterol (OR=1.28, P=.40). Both univariate and multivariate logistic regression analyses found no significant associations between CAD and the other genetic variants, either separately or in combination. In addition, no effects of interactions between the genotypes and environmental factors, such as cigarette smoking, were significantly associated with the risk of CAD.

CONCLUSION

The GST genetic variants examined were not associated with susceptibility to CAD in our Taiwanese cohort. This null association requires further confirmation with larger samples.