Glutathione-S-transferase genotypes, smoking, and their association with markers of inflammation, hemostasis, and endothelial function: the atherosclerosis risk in communities (ARIC) study

Quantile-specific heritability of plasma fibrinogen concentrations

Background

Fibrinogen is a moderately heritable blood protein showing different genetic effects by sex, race, smoking status, pollution exposure, and disease status. These interactions may be explained in part by “quantile-dependent expressivity”, where the effect size of a genetic variant depends upon whether the phenotype (e.g. plasma fibrinogen concentration) is high or low relative to its distribution.

Purpose

Determine whether fibrinogen heritability (h²) is quantile-specific, and whether quantile-specific h² could account for fibrinogen gene-environment interactions.

Methods

Plasma fibrinogen concentrations from 5689 offspring-parent pairs and 1932 sibships from the Framingham Heart Study were analyzed. Quantile-specific heritability from offspring-parent (β_OP, h² = 2β_OP/(1+r_spouse)) and full-sib regression slopes (β_FS, h² = {(1+8r_spouseβ_FS)^0.05–1}/(2r_spouse)) were robustly estimated by quantile regression with nonparametric significance assigned from 1000 bootstrap samples.

Results

Quantile-specific h² (±SE) increased with increasing percentiles of the offspring’s age- and sex-adjusted fibrinogen distribution when estimated from β_OP (P_trend = 5.5x10^-6): 0.30±0.05 at the 10^th, 0.37±0.04 at the 25^th, 0.48±0.05 at the 50^th, 0.61±0.06 at the 75^th, and 0.65±0.08 at the 90^th percentile, and when estimated from β_FS (P_trend = 0.008): 0.28±0.04 at the 10^th, 0.31±0.04 at the 25^th, 0.36±0.03 at the 50^th, 0.41±0.05 at the 75^th, and 0.50±0.06 at the 90^th percentile. The larger genetic effect at higher average fibrinogen concentrations may contribute to fibrinogen’s greater heritability in women than men and in Blacks than Whites, and greater increase from smoking and air pollution for the FGB -455G>A A-allele. It may also explain greater fibrinogen differences between: 1) FGB -455G>A genotypes during acute phase reactions than usual conditions, 2) GTSM1 and IL-6 -572C>G genotypes in smokers than nonsmokers, 3) FGB -148C>T genotypes in untreated than treated diabetics, and LPL PvuII genotypes in macroalbuminuric than normoalbuminuric patients.

Conclusion

Fibrinogen heritability is quantile specific, which may explain or contribute to its gene-environment interactions. The analyses do not disprove the traditional gene-environment interpretations of these examples, rather quantile-dependent expressivity provides an alternative explanation that warrants consideration.

Evaluation of glutathione S-transferase polymorphism in Iranian patients with type 2 diabetic microangiopathy

Background

Overproduction of reactive oxygen species as a result of hyperglycemia in diabetes mellitus leads to microvascular complications. Glutathione S-transferases play important detoxifying roles with antioxidant potentials. This study aimed to assess whether the glutathione S-transferase M1 and T1 genotypes were associated with type 2 diabetes mellitus microangiopathic complications in the Iranian population.

Results

In this case-control study, the frequencies of null GSTM1 and GSTT1 genotypes were 4/72 (5.56%) and 12/72 (16.67%) respectively, in uncomplicated DM group. The frequencies of null GSTM1 and GSTT1 genotype in complicated DM group were 16/134 (11.94%) and 37/134 (27.61%), respectively. The proportion of GSTM1 null genotypes was higher in diabetic nephropathy compared to non-nephropathy (19.3% vs. 6.04 %, P = 0.006). At GSTT1 locus, patients with diabetic peripheral neuropathy had a higher frequency of deletion compared to those of without neuropathy (30.39% vs. 23.49%) (P = 0.02).

Conclusion

Selective polymorphisms encoding GSTM1 and GSTT1genes may prove useful as genetic markers to recognize individuals with an increased trend in developing diabetic nephropathy and neuropathy, respectively. This will help better identify individuals at higher risk toward microvascular complications of type 2 diabetes due to genetic susceptibility.

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

Background

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

Methods

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

Results

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

Conclusion

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

Glutathione S-Transferase Gene Polymorphisms and the Development of New-Onset Diabetes After Liver Transplant

OBJECTIVES

The association between the glutathione S-transferase polymorphisms and the development of new-onset diabetes mellitus after liver transplant was studied.

MATERIALS AND METHODS

Peripheral blood samples were collected from 106 liver transplant patients divided into 2 groups: 52 with new-onset diabetes mellitus and 54 without new-onset diabetes mellitus; 169 healthy individuals with no clinical evidence of diabetes mellitus were selected as a control group. The multiplex polymerase chain reaction technique was used for genotyping GSTM1 and GSTT1 genes, using the cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) gene as an internal control. The genotype of GSTP1 was determined using the restriction fragment length polymorphism-polymerase chain reaction technique.

RESULTS

The frequency of both GSTM1 null and GSTT1 null genotypes was not significantly different in liver transplant patients with new-onset diabetes mellitus compared with the control group (P = .11 for GSTM1; P = .71 for GSTT1). Also, there was no statistically significant association between the frequency of the GSTP1 genotypes in the liver transplant patients with new-onset diabetes mellitus compared with controls. Neither GSTM1 nor GSTT1 null genotypes were associated with the risk of developing new-onset diabetes mellitus (P = .22 for GSTM1; P = .56 for GSTT1). However, the frequency of the heterozygous mutation (AG) in the A313G GSTP1 polymorphism in patients with new-onset diabetes mellitus was significantly higher than in patients without new-onset diabetes mellitus (55.8% vs 7.4%; P = .00). Thus, the risk of developing new-onset diabetes mellitus was significantly higher in patients presenting with heterozygous GSTP1 genotypes (odds ratio = 15.76; 95% confidence interval = 4.53-60.28; P = .00).

CONCLUSIONS

The GSTP1 AG genotype was associated with an increased susceptibility to the development of new-onset diabetes mellitus after liver transplant.

Endothelial dysfunction in cardiovascular disease and Flammer syndrome-similarities and differences

The endothelium has increasingly been recognized as a smart barrier and a key regulator of blood flow in micro- and macrovascular beds. Endothelial dysfunction marks a stage of atherosclerosis and is an important prognostic marker for cardiovascular disease. Yet, some people who tend to be slim and physically active and with rather low blood pressure show a propensity to respond to certain stimuli such as emotional stress with endothelial-mediated vascular dysregulation (Flammer syndrome). This leads to characteristic vascular symptoms such as cold hands but also a risk for vascular-mediated diseases such as normal-tension glaucoma. It is the aim of this review to delineate the differences between Flammer syndrome and its "counterpart" endothelial dysfunction in the context of cardiovascular diseases.

A Japanese cross-sectional multicentre study of biomarkers associated with cardiovascular disease in smokers and non-smokers

We performed a cross-sectional, multicentre study in Japan to detect the differences in biomarkers of exposure and cardiovascular biomarkers between smokers and non-smokers. Several clinically relevant cardiovascular biomarkers differed significantly between smokers and non-smokers, including lipid metabolism (high-density lipoprotein cholesterol concentrations – lower in smokers), inflammation (fibrinogen and white blood cell count – both higher in smokers), oxidative stress (8-epi-prostaglandin F_2α – higher in smokers) and platelet activation (11-dehydro-thromboxane B₂ – higher in smokers) (p ≤ 0.0001). These results provide further evidence showing that cardiovascular biomarkers can discriminate smokers from non-smokers, and could be used to evaluate the risks associated with tobacco products.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Occupational vehicle-related particulate exposure and inflammatory markers in trucking industry workers

BACKGROUND

Previous studies have suggested an association between particulate air pollution and cardiovascular disease, but the mechanism is still unclear.

OBJECTIVE

We examined the association between workplace exposure to vehicle-related particles and cardiovascular disease related systemic inflammatory markers, C-reactive protein (hs-CRP), soluble intercellular adhesion molecule-1 (sICAM-1), and interleukin-6 (IL-6) in 137 trucking terminal workers (non-drivers) in the U.S. trucking industry.

METHODS

We visited two large trucking terminals in 2009 and measured vehicle-related elemental carbon (EC), organic carbon (OC), and particulate matter with aerodynamic diameter ≤2.5µm (PM2.5), for 5 days consecutively at the main work areas. Each participant provided a blood sample and completed a health questionnaire during the sampling period. Individual workplace exposure level was calculated by 12-h time weighted moving averages based on work shift. The association between each blood marker and exposure to each pollutant during 0-12, 12-24, 24-36, and 36-48h before the blood draw was examined by multivariable regression analyses.

RESULTS

In general, OC and EC had a positive association with sICAM-1, especially for exposure periods 12-24 (lag12-24) and 24-36 (lag24-36)h prior to blood draw [β=54.9 (95%CI: 12.3-97.5) for lag12-24 and β=46.5 (95%CI: 21.2-71.8) for lag12-24; change in sICAM-1 (in ng/mL) corresponding to an IQR increase in OC]. A similar pattern was found for EC and PM2.5. We did not find an association between measured pollutants up to 48h before blood draw and hs-CRP or IL-6.

CONCLUSION

In this group of healthy workers, short-term exposure to vehicle-related air pollutants may be associated with sICAM-1. Our findings may be dependent on the exposure period studied.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A single blueberry (Vaccinium corymbosum) portion does not affect markers of antioxidant defence and oxidative stress in healthy volunteers following cigarette smoking

We previously reported that a portion of blueberries reversed endothelial dysfunction induced by acute cigarette smoking. Since smoking-induced endothelial dysfunction is associated with a condition of oxidative stress, we evaluated whether the observed effect was mediated by modulation of markers of oxidative stress and antioxidant defence. Fourteen out of 16 male healthy smokers previously enrolled, participated in a three-armed randomized controlled study with the following experimental conditions: smoking treatment (one cigarette); blueberry treatment (300g of blueberries) + smoking (one cigarette); control treatment (300ml of water with sugar) + smoking (one cigarette). The cigarette was smoked 100min after blueberry/control/water consumption. Each treatment was separated by 1 week of washout period. Plasma vitamin (C, B12 and folate) and aminothiol concentrations, endogenous [formamidopyrimidine-DNA glycosylase (FPG)-sensitive sites] and oxidatively induced DNA damage (resistance to H2O2-induced DNA damage) in peripheral blood mononuclear cells (PBMCs) were measured at baseline and 20, 60, 90, 120min and 24h after smoking. On the whole, analysis of variance did not show a significant effect of treatment on the modulation of markers of oxidative stress and antioxidant defence but revealed an effect of time for plasma concentrations of vitamin C (P = 0.003), B12 (P < 0.001), folate (P < 0.001), total cysteine (P = 0.007) and cysteine-glycine (P = 0.010) that increased following the three treatments after smoking. No significant effect of treatment was observed for the levels of FPG-sensitive sites (P > 0.05) and H2O2-induced DNA damage (P > 0.05) in PBMCs. In conclusion, the consumption of a single blueberry portion failed to modulate markers of oxidative stress and antioxidant defence investigated in our experimental conditions. Further studies are necessary to elucidate this finding and help clarifying the mechanisms of protection of blueberries against smoking-induced endothelial dysfunction.

Glutathione-S-Transferase Variants are not Associated With Increased Carotid Intima-Media Thickness in Turkish Familial Mediterranean Fever Patients

Objectives

This study aims to evaluate the carotid intima-media thickness (CIMT) in patients diagnosed with Familial Mediterranean fever (FMF) and investigate whether there is a relationship between glutathione-S-transferase (GST) gene polymorphisms and CIMT.

Patients and methods

Sixty FMF patients (17 males, 43 females; mean age: 31.43±11.36 years; range 18 to 45 years) and 60 healthy controls (22 males, 38 females; mean age: 29.8±5.82 years; range 18 to 40 years) were enrolled in this study. Polymerase chain reaction-restriction fragment length polymorphism methods were carried out to assess GST polymorphisms. CIMT was measured by carotid ultrasonography. Biochemical parameters were also evaluated using biochemical methods.

Results

Right and left CIMT of FMF patients were statistically significantly higher than that of control group (CIMT right p=0.001 and CIMT left: p=0.033). There was no significant association in terms of GST polymorphisms between FMF and control groups. No significant association was observed between GST polymorphisms and CIMT. Low density lipoprotein, erythrocyte sedimentation rate, and fibrinogen levels were significantly higher in the patient group (p<0.05). The difference between groups was not significant in terms of other biochemical parameters (p>0.05).

Conclusion

Although no significant association was observed between GST polymorphisms and CIMT in FMF patients and controls, CIMT was statistically significantly higher in FMF patients compared to controls.

Polymorphisms in Glutathione S-Transferase M1, T1, and P1 in Patients with Chronic Periodontitis: A Pilot Study

Background. Although the direct cause of chronic periodontitis is bacterial infection, the progression of this disease depends on genetic and environmental factors, and smoking is a known risk factor in the development and severity of the disease. An individual's susceptibility may be influenced by polymorphisms in the glutathione S-transferase genes. These genes encode enzymes that metabolize xenobiotic compounds. The aim of this study was to determine the frequency of GSTM1, GSTT1, and GSTP1 polymorphisms in Mexicans with chronic periodontitis. Methods. 60 Mexicans with chronic periodontitis (30 smokers and 30 nonsmokers) were studied. A peripheral blood sample was taken for subsequent DNA extraction. The genetic material was PCR-amplified followed by restriction fragment length polymorphism with the aim of identifying GST polymorphisms. Results. Polymorphisms in the GSTT1 and GSTP1 genes were not significantly different between the smokers and nonsmokers. However, there were significant differences (P = 0.05) between groups in polymorphisms in the GSTM1 gene. The patients with chronic periodontitis have a higher frequency of null and mutant polymorphisms in GSTM1, GSTT1, and GSTP1 compared with historical data from a healthy Mexican population. Conclusions. The presence of these polymorphisms may be a risk factor for the development of chronic periodontitis.

Reactive metabolites and antioxidant gene polymorphisms in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM), by definition is a heterogeneous, multifactorial, polygenic syndrome which results from insulin receptor (IR) dysfunction. It is an outcome of oxidative stress caused by interactions of reactive metabolites (RMs) with lipids, proteins and other molecules of the human body. Production of RMs mainly superoxides (•O₂⁻) has been found in a variety of predominating cellular enzyme systems including nicotinamide adenine dinucleotide phosphate oxidase, xanthine oxidase, cyclooxygenase, endothelial nitric oxide synthase (eNOS) and myeloperoxidase. The four main RM related molecular mechanisms are: increased polyol pathway flux; increased advanced glycation end-product formation; activation of protein kinase C isoforms and increased hexosamine pathway flux which have been implicated in glucose-mediated vascular damage. Superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase and NOS are antioxidant enzymes involved in scavenging RMs in normal individuals. Functional polymorphisms of these antioxidant enzymes have been reported to be involved in the pathogenesis of T2DM. The low levels of antioxidant enzymes or their non-functionality results in excessive RMs which initiates stress related pathways thereby leading to IR and T2DM. An attempt has been made to review the role of RMs and antioxidant enzymes in oxidative stress resulting in T2DM.

Increased peripheral proinflammatory T helper subsets contribute to cardiovascular complications in diabetic patients

BACKGROUND

Coronary atherosclerotic heart disease (CHD) is one of the major concerns in type 2 diabetes (T2D). The systemic chronic inflammation has been postulated to bridge the increased risk of cardiovascular disease and T2D. We formulated that increased peripheral proinflammatory T helper subsets contributed to the development of cardiovascular complications in diabetic patients.

METHODS

The frequencies of peripheral total CD4+ T helper cells, proinflammatory Th1, Th17, and Th22 subsets were determined by flow cytometry in diabetic patients with or without CHD (n = 42 and 67, resp.).

RESULTS

Both peripheral frequencies and total numbers of Th1, Th17, and Th22 cells were further increased in diabetic patients with CHD. Logistic regression and categorical cross-table analysis further confirmed that increased proinflammatory Th subsets, especially Th22, were independent risk factors of cardiovascular complication in diabetes. Elevated Th subsets also correlated with increased CRP levels and the atherogenic index of plasma. Moreover, Th1 frequency and Th22 numbers demonstrated remarkable potential in predicting CHD in diabetes.

CONCLUSIONS

Increased peripheral proinflammatory T helper subsets act in concert and contribute to the increased prevalence of diabetic cardiovasculopathy. The recently identified Th22 cells might play an independent role in CHD and represent a novel proxy for cardiovascular risks in diabetes.

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.

Reactive metabolites and antioxidant gene polymorphisms in Type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM), by definition is a heterogeneous, multifactorial, polygenic syndrome which results from insulin receptor dysfunction. It is an outcome of oxidative stress caused by interactions of reactive metabolites (RMs) interactions with lipids, proteins and other mechanisms of human body. Production of RMs mainly superoxide (O2−) has been found in a variety of predominating cellular enzyme systems including NAD(P)H oxidase, xanthine oxidase (XO), cyclooxygenase (COX), uncoupled endothelial nitric oxide synthase (eNOS) and myeloperoxidase (MPO). The four main RM related molecular mechanisms are: increased polyol pathway flux; increased advanced glycation end-product (AGE) formation; activation of protein kinase C (PKC) isoforms and increased hexosamine pathway flux which have been implicated in glucose-mediated vascular damage. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST), nitric oxide synthase (NOS) are antioxidant enzymes involved in scavenging RMs in normal individuals. Functional polymorphisms of these antioxidant enzymes have been reported to be involved in pathogenesis of T2DM individuals. The low levels of antioxidant enzymes or their non-functionality results in excessive RMs which initiate stress related pathways thereby leading to insulin resistance and T2DM. An attempt has been made to review the role of RMs and antioxidant enzymes in oxidative stress resulting in T2DM.

•

Four main molecular mechanisms are implicated in glucose-mediated vascular damage.

•

Impaired antioxidant defense contributes to T2DM and related complications.

•

SNPs in antioxidant enzymes are associated with pathogenesis of type 2 diabetes.

•

Genotyping of gene variants in populations will help identify individuals at risk.

Associations between null mutations in GSTT1 and GSTM1, the GSTP1 Ile(105)Val polymorphism, and mortality in breast cancer survivors

Purpose

Here we assessed associations between null mutations in glutathione-S-transferase (GST)T1 and GSTM1 genes, and the rs1695 polymorphism in GSTP1 (Ile¹⁰⁵Val), and risk of breast cancer-specific (n=45) and all-cause (n=99) mortality in a multiethnic, prospective cohort of 533 women diagnosed with stage I-IIIA breast cancer in 1995–1999, enrolled in the Health, Eating, Activity, and Lifestyle (HEAL) Study.

Methods

We measured the presence of the null mutation in GSTT1 and GSTM1, and the rs1695 polymorphism in GSTP1 by polymerase chain reaction. We assessed associations between breast-cancer specific and all-cause mortality using Cox proportional hazards models.

Results

Participants with ER-negative tumors were more likely to be GSTT1 null (χ²=4.52; P=0.03), and African American women were more likely to be GSTM1 null (χ²=34.36; P<0.0001). Neither GSTM1 nor GSTT1 null mutations were associated with breast cancer-specific or all-cause mortality. In a model adjusted for body mass index, race/ethnicity, tumor stage and treatment received at diagnosis, the variant Val allele of rs1695 was associated with increased risk of all-cause (HR=1.81, 95% CI 1.16-2.82, P=0.008), but not breast cancer-specific mortality. The GSTT1 null mutation was associated with significantly higher levels of C-reactive protein.

Conclusions

GSTM1 and GSTT1 null genotypes had no effect on outcome; however the variant allele of rs1695 appears to confer increased risk for all-cause mortality in breast-cancer survivors.

Given the limited sample size of most studies examining associations between GST polymorphisms with breast cancer survival, and the lack of women undergoing more contemporary treatment protocols (treated prior to 1999), it may be helpful to re-examine this issue among larger samples of women diagnosed after the late 1990s, who all received some form of chemotherapy or radiotherapy.

Glutathione S-transferase M1 and T1 genotypes and myocardial infarction

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

Glutathione S-transferase A1, M1, P1 and T1 null or low-activity genotypes are associated with enhanced oxidative damage among haemodialysis patients

BACKGROUND

Increased oxidative stress is a hallmark of end-stage renal disease (ESRD). Glutathione S-transferases (GST) are involved in the detoxification of xenobiotics and protection of oxidative damage. We hypothesized that genetic polymorphism in antioxidant enzymes GSTA1, GSTM1, GSTP1 and GSTT1 is more frequent in ESRD and modulates the degree of oxidative stress in these patients.

METHODS

GSTA1, GSTM1, GSTP1 and GSTT1 genotypes were determined in 199 ESRD patients and 199 age- and gender-matched controls. Markers of protein and lipid oxidative damage [thiol groups, carbonyl groups, advanced oxidative protein products, nitrotyrosine, malondialdehyde (MDA) and MDA adducts], together with total oxidant status and pro-oxidant-antioxidant balance were determined.

RESULTS

Individual GST polymorphisms influence vulnerability to both protein and lipid oxidation, with GSTM1-null gene variant having the most pronounced effect. Furthermore, a strong combined effect of null/low-activity GSTM1, GSTT1, GSTA1 and GSTP1 genotypes in terms of susceptibility towards oxidative and carbonyl stress was found in ESRD patients. When patients were stratified according to GSTM1 and GSTT1, the highest oxidant damage was noted in those with the GSTM1-null/GSTT1-null genotype. The observed effect was even stronger in patients with the third low-activity GSTP1 or GSTA1 genotype. Finally, the level of oxidative and carbonyl stress was most pronounced in the subgroup of patients with all four null or low-activity GSTM1, GSTT1, GSTP1 and GSTA1 genotypes.

CONCLUSIONS

According to the GST genotype, ESRD patients may be stratified in terms of the level of oxidative and carbonyl stress that might influence cardiovascular prognosis, but could also improve efforts towards individualization of antioxidant treatment.

Serum vitamin C and other biomarkers differ by genotype of phase 2 enzyme genes GSTM1 and GSTT1

BACKGROUND

Glutathione S-transferases (GSTs) detoxify environmental chemicals and are involved in oxidative stress pathways. Deletion polymorphisms affect enzyme activities and have been associated with risk of disease.

OBJECTIVE

The objective was to clarify whether biomarkers of oxidation, antioxidation, inflammation, and nutritional factors differ by GST genotype in healthy adults.

DESIGN

Subjects (n = 383) consisted of nonsmokers and nonusers of antiinflammatory drugs and antioxidant vitamin supplements. Deletion polymorphisms of GSTM1 and GSTT1 were genotyped. F(2)-isoprostanes, malondialdehyde, C-reactive protein, serum vitamin C, carotenoids, tocopherols, and other nutritional factors were assessed.

RESULTS

The concentration of serum vitamin C was higher in persons with the inactive GSTM1-0 genotype (P = 0.006). This relation was unchanged after adjustment for age, sex, BMI, or dietary vitamin C. F(2)-isoprostanes and malondialdehyde were lower in the GSTM1-0 and GSTT1-0 groups, respectively, but significance was lost after control for serum vitamin C. The dual deletion, GSTM1-0/GSTT1-0 (n = 37), was associated with higher serum iron and total and LDL-cholesterol concentrations (all P < 0.01) and lower malondialdehyde concentrations, which persisted after adjustment for age, sex, BMI, and serum vitamin C. Carotenoids and α- and γ-tocopherols were not associated with either genotype.

CONCLUSIONS

Oxidative stress and inflammation biomarkers differ by GST genotype, but serum vitamin C appears to be the most consistent factor. Examination of other relevant genes may be needed to understand the concentration and function of ascorbic acid in the GST enzyme system. This trial is registered at clinicaltrials.gov as NCT00079963.

Copy Number Variation in Glutathione S-Transferases M1 and T1 and Ischemic Vascular Disease

Background—

Glutathione S-transferases (GSTs) M1 and T1 detoxify products of oxidative stress and may protect against atherosclerosis and ischemic vascular disease (IVD). We tested the hypothesis that copy number variation (CNV) in GSTM1 and GSTT1 genes, known to be associated with stepwise decreases in catalytic activity, predict risk of IVD.

Methods and Results—

We included 23 059 Danes from 2 general population studies and 2 case-control studies, of whom 4930 had ischemic heart disease (IHD) and 2086 had ischemic cerebrovascular disease. A real-time polymerase chain reaction method genotyped for the exact number of GSTM1 and GST T1 gene copies. We also performed meta-analyses, including our own and former studies, totaling 13 196 IHD cases and 33 228 controls. CNV in GSTM1 or GSTT1 or genotype combinations were not associated with an increased risk of IHD, myocardial infarction, ischemic cerebrovascular disease, ischemic stroke, or any ischemic vascular event in studies individually or combined or in the meta-analyses. Furthermore, genotypes did not interact with smoking on risk of disease end points. Finally, GST genotypes did not associate with markers of inflammation and oxidation or interact with smoking on markers of inflammation in the general population. In contrast, we observed the well-established association between CNV in GSTM1 and risk of bladder cancer.

Conclusions—

In studies including 6557 IVD cases and 16 502 controls and in meta-analyses of 13 196 cases and 33 228 controls, CNV in GSTM1 and GST T1 genes did not associate with risk of IVD or with markers of inflammation. These observations were independent of smoking exposure.

The association between GSTT1, M1, and P1 polymorphisms with coronary artery disease in Western Iran

DNA damage which occurred by the effect of oxidant and mutant agents has an essential role in the development of atherosclerosis. To investigate the possible association between GSTs polymorphism with coronary artery disease (CAD), we investigated the frequency of GSTT1, M1, and P1 genotypes in patients with CAD compared to controls. The genotypes of GSTT1, M1, and P1 were determined in 209 angiographically documented CAD patients and 108 normal coronary artery cases (as controls) by Multiplex Polymerase Chain Reaction and PCR-RFLP. In CAD patients, the frequency of GSTT1-null genotype was significantly (P = 0.025) lower than that in control. The presence of this genotype was associated with 2.2-fold increased risk of CAD. However, the frequency of GSTM1 and GSTP1 genotypes were not significantly different comparing both groups (P = 0.405 and P = 0.521, respectively). Moreover, non smokers patients had a lower frequency of GSTM1-null genotype (29.2%) compared to non smoker controls (43.5%, P = 0.043). Also, the frequency of both GSTT1-null and GSTM1-null genotypes in patients (3.8%) was significantly lower compared to controls with the same genotypes (10.2%, P = 0.014). Our results indicated that a reduction in the frequency of GSTT1-null and GSTM1-null genotypes that observed in our study might be involved in the pathogenesis of CAD in our population.

Genetic polymorphisms influence runners' responses to the dietary ingestion of antioxidant supplementation based on pequi oil (Caryocar brasiliense Camb.): a before-after study

Genes have been implicated in the levels of oxidative stress, lipids, CVD risk, immune reactivity, and performance. Pequi oil (Caryocar brasiliense) has shown anti-inflammatory and hypotensive effects, besides reducing exercise-induced DNA, tissue damages, and anisocytosis. Given that diet can interact with the human genome to influence health and disease, and because genetic variability can influence response to diet, we aim to investigate the influence of 12 gene polymorphisms on inflammatory markers, postprandial lipids, arterial pressure, and plasma lipid peroxidation of runners (N = 125), before and after 14 days of 400 mg pequi-oil supplementation, after races under closely comparable conditions. Arterial pressure was checked before races; blood samples were taken immediately after racing to perform leukogram and plateletgram, Tbars assay, lipid, and CRP dosages and genotyping. CAT, GST-M1/T1, CRP-G1059C, and MTHFR-C677T polymorphisms influenced post-pequi-oil responses in leukogram; Hp and MTHFR-C677T, in plateletgram; Hp, ACE, GSTT1, and MTHFR-A1298C, in lipid profile; MTHFR-A1298C, in C-reactive protein (CRP) levels; and Hp and MnSOD, in Tbars assay. Differences between ACE genotypes in leukogram and total cholesterol disappeared after pequi, and the same occurred for Hp and MnSOD in Tbars assay and for MTHFR-A1298C with CRP levels. Because genetic inheritance is one of the factors that drive atherosclerosis-related lipid abnormalities, results can contribute to a greater understanding of the influence of genetic polymorphisms in situations that push up free radicals. Knowledge is also expanded on how antioxidant supplementation affects an individual's genes and how athletic genetic makeup can affect the way a person responds to antioxidant supplements.

Interaction between GSTM1 genotype and IL-6 on mortality in older adults: results from the ilSIRENTE study

BACKGROUND AND AIMS

The inflammatory process is related to oxidative stress and inflammation was proven to be a strong determinant of the aging process and to ultimately lead to death. The aim of the present study was to assess if, in a population of older adults, the effect of antioxidant genes GSTM1 and GSTT1 genotypes on mortality may differ depending on levels of inflammation.

METHODS

Data are from 353 older persons aged ≥80 years enrolled in the ilSIRENTE study. Study population was divided into two groups computed based on the median value of serum IL-6 (low IL-6, n=177 and high IL-6, n=176). All participants were followed up for 48 months.

RESULTS

Mean age of study participants was 85.8 years (Standard Deviation 4.8), 235 (66.6%) were women. Overall 48/177 participant (27.1%) in the low IL-6 group died during the study period, compared with 97/176 (55.1%) in the high IL-6 group (p<0.001). After adjusting for potential confounders, GSTM1 wildtype had no effect on mortality in the low IL-6 group (RR=1.07; 95% CI 0.46-2.47), but it was associated with a significant lower mortality rate in the high IL-6 level (RR=0.33; 95% CI 0.15-0.69). Testing the interaction between IL-6 and GSTM1 genotype, we found a significant result (p=0.02). No significant effect of GSTT1 genotype on mortality was shown in participants with low and high IL-6 level.

CONCLUSION

GSTM1 wildtype is associated with reduced mortality among older adults with high levels of inflammation, but not among those with low levels of inflammation.

DNA repair gene polymorphism is associated with the genetic basis of atherosclerotic coronary artery disease

BACKGROUND

Atherosclerotic coronary artery disease (CAD) is a multifactorial process that appears to be caused by the interaction of environmental risk factors with multiple predisposing genes. It is nowadays accepted that increased levels of DNA damage induced by xenobiotics play an important role in the early phases of atherogenesis. Therefore, in this study, we focus on determining whether genetic variations in xenobiotic-metabolizing [glutathione-S-transferase theta 1 (GSTT1), glutathione-S-transferase mu 1 (GSTM1), cytochrome P450 IIEI (CYP2E1)] and DNA repair [X-ray cross-complementing group 1 (XRCC1)] genes might be associated with increased risk for CAD.

METHODS

A case-control study was conducted with 400 individuals who underwent subjected to coronary angiography. A total of 299 were patients diagnosed with effective coronary atherosclerosis (case group; >20% obstructive lesion), and 101 (control group) were individuals diagnosed as negative for CAD (<20% obstructive lesions). The polymorphism identifications for GSTM1 and GSTT1, and for CYP2E1 and XRCC1 genes were performed by polymerase chain reaction (PCR) amplification and by PCR-RFLP, respectively.

RESULTS AND CONCLUSIONS

The XRCC1 homozygous wild-type genotype Arg/Arg for codon 399 was statistically less pronounced in the case subjects (21.4%) than in controls (38.5%); individuals with the variant XRCC1 genotype had a 2.3-fold increased risk for coronary atherosclerosis than individuals with the wild-type genotype (OR=2.3, 95% CI=1.13-4.69). Conversely, no association between GSTM1, GSTT1, and CYP2E1gene polymorphisms and coronary atherosclerosis was detected. The results provide evidence of the role of DNA damage and repair in cardiovascular disease.

Oxidative risk for atherothrombotic cardiovascular disease

In the vasculature, reactive oxidant species, including reactive oxygen, nitrogen, or halogenating species, and thiyl, tyrosyl, or protein radicals may oxidatively modify lipids and proteins with deleterious consequences for vascular function. These biologically active free radical and nonradical species may be produced by increased activation of oxidant-generating sources and/or decreased cellular antioxidant capacity. Once formed, these species may engage in reactions to yield more potent oxidants that promote transition of the homeostatic vascular phenotype to a pathobiological state that is permissive for atherothrombogenesis. This dysfunctional vasculature is characterized by lipid peroxidation and aberrant lipid deposition, inflammation, immune cell activation, platelet activation, thrombus formation, and disturbed hemodynamic flow. Each of these pathobiological states is associated with an increase in the vascular burden of free radical species-derived oxidation products and, thereby, implicates increased oxidant stress in the pathogenesis of atherothrombotic vascular disease.

Air pollution, obesity, genes and cellular adhesion molecules

OBJECTIVES

Particulate matter has been associated with acute cardiovascular outcomes, but our understanding of the mechanism is incomplete. We examined the association between particulate matter and cell adhesion molecules. We also investigated the modifying effect of genotype and phenotype variation to gain insight into the relevant biological pathways for this association.

METHODS

We used mixed regression models to examine the association of PM(2.5) (particulate matter < or = 2.5 microm in diameter) and black carbon with serum concentrations of soluble intercellular adhesion molecule (sICAM-1) and soluble vascular cell adhesion molecule (sVCAM-1), markers of endothelial function and inflammation, in a longitudinal study of 809 participants in the Normative Ageing Study (1819 total observations). We also examined whether this association was modified by genotype, obesity or diabetes status. Genes selected for analyses were either related to oxidative stress, endothelial function, lipid metabolism or metal processing.

RESULTS

Black carbon during the 2 days prior to blood draw was significantly associated with increased sVCAM-1 (4.5% increase per 1 microg/m(3), 95% CI 1.1 to 8.0). Neither pollutant was associated with sICAM-1. Larger effects of black carbon on sVCAM were seen in subjects with obesity (p=0.007) and who were GSTM1 null (p=0.02).

CONCLUSIONS

Black carbon is associated with markers of endothelial function and inflammation. Genes related to oxidative defence may modify this association.

GST M1 polymorphism associates with DNA oxidative damage and mortality among hemodialysis patients

Leukocyte 8-hydroxy-2'-deoxyguanosine (8-OHdG) is a surrogate marker of oxidant-induced DNA damage in patients undergoing maintenance hemodialysis (MHD). Glutathione S-transferase M1 (GST M1) is a member of the GST family of proteins, which protect cellular DNA against oxidative damage. This study tested the association of a common GST M1 gene polymorphism [GST M1(-)], known to produce a dysfunctional enzyme, with levels of 8-OHdG in peripheral blood leukocytes and all-cause mortality among MHD patients. Among 488 MHD patients and 372 gender-matched healthy subjects, the frequency of the GST M1(-) genotype was 63.1 and 60.2%, respectively. The GST M1(-) genotype was associated with significantly higher levels of leukocyte 8-OHdG compared with the GST M1(+) genotype, even after adjustment for potential confounders (P < 0.001). Moreover, GST M1(-) patients who also had a common polymorphism in the DNA repair enzyme 8-oxoguanine DNA glycosylase 1 or who underwent dialysis with a bioincompatible cellulose membrane had the highest median levels of leukocyte 8-OHdG. Multivariate Cox regression revealed that among MHD patients, GST M1(-) genotype approximately doubled the risk for all-cause mortality (hazard ratio 2.24; 95% confidence interval 1.30 to 4.51) during the mean follow-up of 34 mo. In conclusion, patients without GST M1 activity are more vulnerable to oxidative stress and are at greater risk for death compared with those who possess GST M1 activity.

Polymorphisms in the NQO1, GSTT and GSTM genes are associated with coronary heart disease and biomarkers of oxidative stress

It was hypothesized that the presence of genetic polymorphisms that decrease activity of the detoxification enzymes glutathione-S-transferase (GST) and quinone oxido-reductase (NQO1) may contribute to heart disease and affect biomarkers of coronary health and oxidative stress. Sixty-seven patients with angiographically confirmed coronary heart disease (CHD) and 63 healthy controls were genotyped for polymorphisms in the GST isoforms Mu and Theta (GSTM and GSTT respectively) and NQO1. Participants' blood levels of homocysteine (Hcy), C-reactive protein (CRP), oxidized low density lipoprotein (LDL) and total antioxidant capacity (TAOX) were measured. TAOX levels were significantly lower in women than men (P < or = 0.001) and this finding was more marked in the control group (P < or = 0.001). Hcy levels were higher in CHD patients (P=0.003 vs. control) which was mostly attributed to female patients (P=0.034 case vs. control). GSTM polymorphisms were present with greater frequencies in CHD cases with the odds ratio (OR) for GSTM equal to 3.77 vs. control. CHD patients also have an increased incidence of both GSTM and GSTT null polymorphisms (OR=5.13). In contrast, NQO1 polymorphisms were protective in CHD patients (OR=0.18 vs. control), which when stratified for genotype was due to heterozygous individuals. Significantly higher C-reactive protein levels occurred in CHD patients with lower NQO1 activity (P=0.001), however, due to the large variations in CRP levels seen in CHD patients; the clinical importance of this difference is unclear. Smokers with the GSTM null polymorphism were more likely to have CHD than non-smokers expressing the GSTM null polymorphism (OR=3.54, P=0.079). We conclude that a lack of activity in the detoxification enzymes NQO1 and GSTM, and biomarker levels are strongly associated with coronary heart disease with sex as a mitigating factor.

Cardioprotective effects of Sesbania grandiflora in cigarette smoke-exposed rats

Cigarette smoke is a major risk factor of coronary heart disease, myocardial infarction, and cardiac death. It has been reported to contain large amounts of oxidants. This study was undertaken to evaluate the cardioprotective effects of Sesbania grandiflora (S. grandiflora) against cigarette smoke-induced oxidative damage in rats. Adult male Wistar-Kyoto rats were exposed to cigarette smoke for a period of 90 days and consecutively treated with S. grandiflora aqueous suspension (SGAS, 1000 mg/kg body weight per day orally) for a period of 3 weeks. Lactate dehydrogenase activity in serum and cardiac lipid peroxidation product level were significantly increased while the activities of cardiac superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, and glucose-6-phosphate dehydrogenase then the levels of reduced glutathione, vitamin C, and vitamin E were significantly decreased in rats exposed to cigarette smoke. Besides, copper level was elevated, whereas zinc, manganese, and selenium levels were significantly diminished in the heart of rats exposed to cigarette smoke. Treatment with SGAS restored the antioxidant status and retained the levels of micronutrients. These results suggest that chronic cigarette smoke exposure increases the oxidative stress, thereby disquieting the cardiac defense system and S. grandiflora protects the heart from the oxidative damage through its antioxidant potential.

Combined glutathione S-transferase T1 and M1 positive genotypes afford protection against type 2 diabetes in Japanese

INTRODUCTION

Diabetes mellitus is associated with an increased production of reactive oxygen species and a reduction in antioxidant defenses. The aim of this study is to determine the association between the incidence of Type 2 diabetes and gene polymorphisms of glutathione S-transferase (GST), which modulates oxidative stress.

MATERIALS & METHODS

The associations between the incidence of Type 2 diabetes and the GSTT1 and GSTM1 genotypes were analyzed in 469 Japanese participants in a health-screening program.

RESULTS

The clinical characteristics and smoking status were obtained from the health screening record. The incidence of diabetes was 1.5-fold higher in the GSTT1 and GSTM1 null (-) genotype than the GSTT1 and GSTM1 present (+) genotype, respectively. Although the effect of each null genotype was not significant, the combined GSTT1+/GSTM1+ genotypes conferred a significant reduction in risk of diabetes in comparison with the other combinations of genotypes (adjusted odds ratio [OR]: 0.30; 95% confidence interval [CI]: 0.12-0.71). In stratified analyses by smoking status, the incidence of diabetes was significantly higher in never-smokers with the GSTT1- genotype than those with the GSTT1+ genotype (OR: 2.85; 95% CI: 1.17-6.94) and increased significantly in current smokers (OR: 5.91; 95% CI: 1.96-17.88). The effect of the GSTM1- genotype was significant only in current smokers.

CONCLUSION

This study demonstrated that the GSTT1- and GSTT1-/GSTM1- genotypes are independent risk factors for development of Type 2 diabetes regardless of the smoking status of the patient, and that these genotypes and current smoking were interactively associated with the incidence of Type 2 diabetes.

Leukocyte telomere length and carotid artery intimal medial thickness: the Framingham Heart Study

BACKGROUND AND PURPOSE

Leukocyte telomere length (LTL) is relatively short in individuals who have evidence of cardiovascular disease. The purpose of this study was to examine the link between LTL and the predisposition to atherosclerosis, as determined by carotid artery intimal medial thickness (IMT) in participants of the Framingham Offspring Study.

METHODS AND RESULTS

LTL was assayed by the mean length of the terminal restriction fragments and carotid artery IMT by B-mode ultrasonography in 1062 individuals (496 men, 566 women) aged 33 to 86 years. In the whole sample, there was a significant association of age-and sex-adjusted LTL with internal carotid artery IMT (ICA-IMT) (r = -0.07, P = 0.02). In sex-stratified analysis, this association remained significant for men (r = -0.11, P = 0.02) but not for women (r = -0.04, P = 0.36). After further adjustment for cigarette smoking and BMI, a borderline significant association persisted in men (P = 0.06). In secondary analysis, the age-adjusted LTL was significantly (and negatively) associated with ICA-IMT (r = -0.28, p = 0.0006) in obese (BMI > 30 kg/m(2)) men but not in nonobese (BMI < or = 30 kg/m(2)) men. In addition, age-adjusted LTL was significantly shorter in men (6.89+/-0.02 kb) than women (7.01+/-0.02 kb; P < 0.0009) and in current cigarette smokers (6.87+/-0.05 kb) than never smokers (6.99+/-0.03 kb; P = 0.0006). Although there was no significant association of LTL with common carotid artery-IMT or with carotid artery stenosis, there was a significant inverse association of LTL with common carotid artery IMT in obese men.

CONCLUSIONS

In obese men, shortened LTL is a powerful marker of increased carotid IMT. Given the public health impact of atherosclerosis and in particular the current epidemic of obesity, the associations noted in obese men warrant further confirmation.

Protein expression changed by nicotine in rat vascular smooth muscle cells

In order to observe the effects of nicotine on protein expression in rat vascular smooth muscle cells (SMCs), nicotine treated SMCs were studied by proteomic technologies combining two-dimensional electrophoresis (2-DE) and peptide mass fingerprinting (PMF). Real-time RT-PCR was used to validate the differentially expressed proteins. We found that 11 protein spots were significantly up-regulated and one down-regulated by nicotine treatment. The results of PMF showed that these up- and down-regulated proteins could be divided into three groups according to their functions: cytoskeleton proteins, regulatory proteins and enzymes. Simultaneously, we also verified their consistent alteration at the transcriptional level through real-time RT-PCR. The affected proteins turned out to be mainly associated with cell migration, proliferation and energy metabolism, and are responsible for nicotine-related cardiovascular damage.

Association of periodontitis with GSTM1/GSTT1-null variants—A pilot study

OBJECTIVES

To analyze a possible association between glutathione-S-transferase T1 (GSTM1) and/or glutathione-S-transferase M1 (GSTM1) polymorphisms and chronic or aggressive forms of periodontitis in a Caucasian ethnic group.

DESIGN AND METHODS

Sixty-nine chronic, 14 aggressive periodontitis and 61 controls, deeply analyzed from a clinical point of view, were studied for their GSTM1 and GSTT1 polymorphisms by allelic specific PCR techniques. As a second control group, 64 blood donors were also included.

RESULTS

A significant association was found between GSTM1-null genotype and both chronic and aggressive periodontitis. The aggressive forms were associated with the double null GSTM1 and GSTT1 combination. These results were independent of the patients' age, gender, hygienic habits and smoke (evaluated as tobacco smoking yes/no, cigarettes/day and pack years) as confirmed by multivariate logistic regression analysis.

CONCLUSIONS

The GSTM1-null variant is statistically associated with the two forms of periodontitis, while the aggressive one also presents a second null variant: GSTT1.

Glutathione S-transferase M1 and GST T1 genetic polymorphisms and Raynaud’s phenomenon in French vinyl chloride monomer-exposed workers

Occupational vinyl chloride monomer (VCM) exposure can induce Raynaud's phenomenon (RP). However, not all VCM workers developed RP, which suggests an underlying genetic susceptibility. Genetic polymorphisms of glutathione S-transferases (GSTs), involved in VCM metabolism, have been shown to influence certain VCM-related health effects. We have conducted a case-control study of 58 subjects with RP along with 247 subjects without RP, from a population of 305 French workers exposed or formerly exposed to VCM, to assess any association between GST M1 and GST T1 gene polymorphisms, either separately or in combination, and the presence of RP. None of the GST M1 or GST T1 genotypes were significantly associated with the presence of RP among studied VCM workers. A combination of positive genotypes for both GST M1 and GST T1 was significantly associated with RP presence, compared to the other combinations of genotypes (OR=2.1, 95% CI=1.1-3.8). OR adjusted for age, smoking status, alcohol consumption and history of treated hypertension did not reach significance (OR=2.0, 95% CI=0.9-5.2). None of the GST M1 and GST T1 genotypes seem to contribute separately to the presence of RP, suggesting that they are not, when taken alone, a major determinant of interindividual variability for VCM-induced PR. However, the combination of both positive GST M1 and GST T1 genotypes appears to contribute slightly to susceptibility to RP in VCM-exposed subjects. Nevertheless, our study-the first to examine the role of a genetic component in the occurrence of RP secondary to occupational exposure to a chemical-corroborates the previous considerations that interaction between the genetic constitution and environmental factors is of importance in determining the health-adverse effects of VCM exposure.

Inflammation in carotid atherosclerotic plaque: a dynamic contrast-enhanced MR imaging study

PURPOSE

To prospectively evaluate if there is an association between plaque enhancement at magnetic resonance (MR) imaging and proinflammatory cardiovascular risk factors and plaque content.

MATERIALS AND METHODS

This study was performed with informed consent, HIPAA compliance, and institutional review board approval. Contrast agent dynamics within carotid plaques were measured in 30 patients (29 men, one woman; mean age, 67.7 years +/- 10.7 [standard deviation]) who were scheduled to undergo carotid endarterectomy. Measurements were based on kinetic modeling of images obtained at 15-second intervals during which a gadolinium-based contrast agent was injected. The time-varying signal intensities within the plaques were used to estimate the fractional plasma volume (vp) and transfer constant (Ktrans) of contrast material into the extracellular space. Pearson correlation coefficients were computed between blinded MR measurements and histologic measurements of plaque composition, including macrophages, neovasculature, necrotic core, calcification, loose matrix, and dense fibrous tissue. Correlation coefficients or mean differences were computed regarding clinical markers of cardiovascular risk.

RESULTS

Analyzable MR images and histologic results were obtained in 27 patients. Measurements of Ktrans correlated with macrophage (r = 0.75, P < .001), neovasculature (r = 0.71, P < .001), and loose matrix (r = 0.50, P = .01) content. Measurements of v(p) correlated with macrophage (r = 0.54, P = .004), neovasculature (r = 0.68, P < .001), and loose matrix (r = 0.42, P = .03) content. For clinical parameters, significant associations were correlated with Ktrans only, with decreased high-density lipoprotein levels (r = -0.66, P < .001) and elevated Ktrans measurements in smokers compared with nonsmokers (mean, 0.134 min(-1) vs 0.074 min(-1), respectively; P = .01).

CONCLUSION

The correlations between Ktrans and histologic markers of inflammation suggest that Ktrans is a quantitative and noninvasive marker of plaque inflammation, which is further supported by the correlation of Ktrans with proinflammatory cardiovascular risk factors, decreased high-density lipoprotein levels, and smoking.

T null and M null genotypes of the glutathione S-transferase gene are risk factor for CAD independent of smoking

Background

The association of the deletion in GSTT1 and GSTM1 genes with coronary artery disease (CAD) among smokers is controversial. In addition, no such investigation has previously been conducted among Arabs.

Methods

We genotyped 1054 CAD patients and 762 controls for GSTT1 and GSTM1 deletion by multiplex polymerase chain reaction. Both CAD and controls were Saudi Arabs.

Results

In the control group (n = 762), 82.3% had the T ^wild M ^wildgenotype, 9% had the T^wild M ^null, 2.4% had the T^null M ^wild and 6.3% had the T^null M ^null genotype. Among the CAD group (n = 1054), 29.5% had the T^wild M ^wild genotype, 26.6% (p < .001) had the T^wild M ^null, 8.3% (p < .001) had the T^null M ^wild and 35.6% (p < .001) had the T^null M ^null genotype, indicating a significant association of the T^wild M ^null, T^null M ^wild and T^null M ^null genotypes with CAD. Univariate analysis also showed that smoking, age, hypercholesterolemia and hypertriglyceridemia, diabetes mellitus, family history of CAD, hypertension and obesity are all associated with CAD, whereas gender and myocardial infarction are not. Binary logistic regression for smoking and genotypes indicated that only M ^null and T^nullare interacting with smoking. However, further subgroup analysis stratifying the data by smoking status suggested that genotype-smoking interactions have no effect on the development of CAD.

Conclusion

GSTT1 and GSTM1 null-genotypes are risk factor for CAD independent of genotype-smoking interaction.

Oxidative Enzymopathies and Vascular Disease

In the vasculature, reactive oxygen species (ROS) generated by both mitochondrial respiration and enzymatic sources serve as integral components of cellular signaling and homeostatic mechanisms. Because ROS are highly reactive biomolecules, the cellular redox milieu is carefully maintained by small-molecule antioxidants and antioxidant enzymes to prevent the deleterious consequences of ROS excess. When this redox balance is perturbed, because of either increased ROS production or decreased antioxidant capacity, oxidant stress is increased in the vessel wall and, if not offset, vascular dysfunction ensues. A number of heritable polymorphisms of pro-oxidant enzymes, including 5-lipoxygenase, cyclooxygenase-2, nitric oxide synthase-3, and NAD(P)H oxidase, have been identified and found to modulate ROS production and, thereby, the risk of atherothrombotic cardiovascular disease in individuals with these genetic polymorphisms. Similarly, heritable deficiency of the antioxidant enzymes catalase, glutathione peroxidases, glutathione- S -transferases, heme oxygenase, and glucose-6-phosphate dehydrogenase favors ROS accumulation, and has been associated with an increased risk of vascular disease. Individually, each of these polymorphisms imposes a state of uncompensated oxidant stress on the vasculature and collectively comprise the oxidative enzymopathies.

A physiogenomic approach to study the regulation of blood pressure

Several vasoregulatory systems including the renin-angiotensin system, sympathetic vasoregulation, and cytokine release have been studied extensively. The aim of the present study was to establish a physiogenomic screening model for differentially expressed genes in the regulation of blood pressure that might give a hint as to new vasoregulatory mechanisms. We induced acute hypotension in normotensive rats, assuming that vasoregulatory systems will counteract hypotension. Microarray transcriptome analysis was performed from kidneys 6 h after the induction of acute hypotension. The results were confirmed by real-time PCR. Six functionally known genes (Igfbp1, Xdh, Sult1a1, Mawbp, Por, and Gstm1) and two expressed sequence tages (BI277460 and AI411345) were significantly upregulated. Four of these genes (Igfbp1, Xdh, Por, and Gstm1) have well-characterized functions in the cardiovascular system. The proteins corresponding to Xdh, Por, and Gstm1 are involved in the metabolism of reactive oxygen species (ROS). Because ROS can mediate endothelial dysfunction, we measured the aortic dilatory capacity in thoracic aortic rings. Indeed, vasodilator potency to acetylcholine was largely diminished in hypotensive animals, whereas sodium nitroprusside induced equivalent vasodilations in normotensive and hypotensive animals. The vasodilator potency of the endothelium was partially restored by the superoxide scavenger tiron. Hence, acute hypotension induces a diminished vasodilator potency of the endothelium due to an accelerated degradation of nitric oxide by ROS. The present physiogenomic approach is capable of detecting vasoregulatory mechanisms and may provide deeper insight into the genetics and physiology of blood pressure regulation.

Reduction of Gstm1 Expression in the Stroke-Prone Spontaneously Hypertension Rat Contributes to Increased Oxidative Stress

Human essential hypertension is a classic example of a complex, multifactorial, polygenic disease with a substantial genetic influence in which the underlying genetic components remain unknown. The stroke-prone spontaneously hypertension rat (SHRSP) is a well-characterized experimental model for essential hypertension and endothelial dysfunction. Previous work, identified glutathione S -transferase μ type 1, a protein involved in detoxification of reactive oxygen species, as a positional and functional candidate gene. Quantitative real-time polymerase chain reaction showed a highly significant, 4-fold reduction of glutathione S -transferase μ type 1 mRNA expression in 5- and 16-week-old SHRSP compared with the congenic and normotensive Wistar Kyoto rats. This suggests that differential expression is not attributable to long-term changes in blood pressure. DNA sequencing identified one coding single nucleotide polymorphism (R202H) and multiple single nucleotide polymorphisms in the promoter region. mRNA expression changes were reflected at the protein level, with significant reductions in the SHRSP glutathione S -transferase μ type 1. Protein was colocalized with aquaporin 2 to the principle cells of the renal collecting ducts. Coupled to significant increases in nitrotyrosine levels in the kidney, this suggests a pathophysiological role of this protein in hypertension and oxidative stress. Similar processes may underlie oxidative stress in the vasculature.