Homozygous Deletion Of GSTM1 Gene Research Articles

Vitamin E-Bonded Membranes Do Not Influence Markers of Oxidative Stress in Hemodialysis Patients with Homozygous Glutathione Transferase M1 Gene Deletion.

Background: Increased oxidative stress is a hallmark of end-stage renal disease. Hemodialysis (HD) patients lacking glutathione transferase M1 (GSTM1) enzyme activity exhibit enhanced oxidative DNA damage and higher mortality rate than those with active GSTM1 enzyme. To our knowledge, this is the first study to use the vitamin E-bonded membranes (VEM) in patients with homozygous GSTM1 gene deletion, and we aimed to determine the effect of VEM on oxidative and inflammatory status in HD patients with homozygous GSTM1 gene deletion. Methods: GSTM1 genotypes were determined by polymerase chain reaction (PCR) in 170 chronic HD patients. Those with GSTM1-null genotype were randomized and 80 were included in the study. Forty of them were dialyzed for three months with VEM, while the other forty were dialyzed with high-flux same-surface polysulfone dialyzers. Markers of protein and lipid oxidative damage and inflammation (thiol groups, malondialdehyde (MDA), Interleukin-6 (IL-6)), together with plasma antioxidant activity (glutathione peroxidase (GPX), superoxide dismutase (SOD)) were determined. Results: Seventy-five patients finished the study. There were no differences at baseline in markers of protein and lipid oxidative damage, inflammation and plasma antioxidant activity. After three months of therapy, GPX, MDA, and thiol groups increased significantly in both groups, but without statistical significance between groups. SOD and C reactive protein (CRP) did not change significantly during the three-month period. IL-6 increased in the control group, and at the same time, decreased in the VEM group, but without statistical significance. Hemoglobin (Hb) value, red blood cells, erythropoiesis resistance index (ERI), serum ferritin and iron did not change significantly within or between groups. Regarding other laboratory parameters, proteins, albumins, triglycerides, serum phosphorus, serum bicarbonate and Kt/V showed significant improvements within groups but with no significant difference between groups. Conclusions: Our data shows that therapy with VEM over three months had no benefit over standard polysulfone membrane in decreasing by-products of oxidative stress and inflammation in dialysis patients lacking GSTM1 enzyme activity.

Association of long-term exposure to traffic-related PM10 with heart rate variability and heart rate dynamics in healthy subjects

BackgroundEpidemiological evidence on the influence of long-term exposure to traffic-related particulate matter (TPM10) on heart rate variability (HRV) is weak. ObjectiveTo evaluate the association of long-term exposure (10 years) with TPM10 on the regulation of the autonomic cardiovascular system and heart rate dynamics (HRD) in an aging general population, as well as potential modifying effects by the a priori selected factors sex, smoking status, obesity, and gene variation in selected glutathione S-transferases (GSTs). MethodsWe analyzed data from 1593 SAPALDIA cohort participants aged ≥ 50 years. For each participant, various HRV and HRD parameters were derived from 24-hour electrocardiogram recordings. Each parameter obtained was then used as the outcome variable in multivariable mixed linear regression models in order to evaluate the association with TPM10. Potential modifying effects were assessed using interaction terms. ResultsNo association between long-term exposure to TPM10 and HRV/HRD was observed in the entire study population. However, HRD changes were found in subjects without cardiovascular morbidity and both HRD and HRV changes in non-obese subjects without cardiovascular morbidity. Subjects without cardiovascular morbidity with homozygous GSTM1 gene deletion appeared to be more susceptible to the effects of TPM10. ConclusionThis study suggests that long-term exposure to TPM10 triggers adverse changes in the regulation of the cardiovascular system. These adverse effects were more visible in the subjects without cardiovascular disease, in whom the overall relationship between TPM10 and HRV/HRD could not be masked by underlying morbidities and the potential counteracting effects of related drug treatments.

MTHFR Glu429Ala and ERCC5 His46His Polymorphisms Are Associated with Prognosis in Colorectal Cancer Patients: Analysis of Two Independent Cohorts from Newfoundland

IntroductionIn this study, 27 genetic polymorphisms that were previously reported to be associated with clinical outcomes in colorectal cancer patients were investigated in relation to overall survival (OS) and disease free survival (DFS) in colorectal cancer patients from Newfoundland.MethodsThe discovery and validation cohorts comprised of 532 and 252 patients, respectively. Genotypes of 27 polymorphisms were first obtained in the discovery cohort and survival analyses were performed assuming the co-dominant genetic model. Polymorphisms associated with disease outcomes in the discovery cohort were then investigated in the validation cohort.ResultsWhen adjusted for sex, age, tumor stage and microsatellite instability (MSI) status, four polymorphisms were independent predictors of OS in the discovery cohort MTHFR Glu429Ala (HR: 1.72, 95%CI: 1.04–2.84, p = 0.036), ERCC5 His46His (HR: 1.78, 95%CI: 1.15–2.76, p = 0.01), SERPINE1 −675indelG (HR: 0.52, 95%CI: 0.32–0.84, p = 0.008), and the homozygous deletion of GSTM1 gene (HR: 1.4, 95%CI: 1.03–1.92, p = 0.033). In the validation cohort, the MTHFR Glu429Ala polymorphism was associated with shorter OS (HR: 1.71, 95%CI: 1.18–2.49, p = 0.005), although with a different genotype than the discovery cohort (CC genotype in the discovery cohort and AC genotype in the validation cohort). When stratified based on treatment with 5-Fluorouracil (5-FU)-based regimens, this polymorphism was associated with reduced OS only in patients not treated with 5-FU. In the DFS analysis, when adjusted for other variables, the TT genotype of the ERCC5 His46His polymorphism was associated with shorter DFS in both cohorts (discovery cohort: HR: 1.54, 95%CI: 1.04–2.29, p = 0.032 and replication cohort: HR: 1.81, 95%CI: 1.11–2.94, p = 0.018).ConclusionsIn this study, associations of the MTHFR Glu429Ala polymorphism with OS and the ERCC5 His46His polymorphism with DFS were identified in two colorectal cancer patient cohorts. Our results also suggest that the MTHFR Glu429Ala polymorphism may be an adverse prognostic marker in patients not treated with 5-FU.

Antioxidant enzyme polymorphisms and neuropsychological outcomes in medulloblastoma survivors: a report from the Childhood Cancer Survivor Study

Psychological or neurocognitive impairment is often seen in medulloblastoma survivors after craniospinal radiation; however, significant variability in outcomes exists. This study investigated the role of antioxidant enzyme polymorphisms in moderating this outcome and hypothesized that patients who had polymorphisms associated with lower antioxidant enzyme function would have a higher occurrence of impairment. From the Childhood Cancer Survivor Study (CCSS) cohort, 109 medulloblastoma survivors and 143 siblings were identified who completed the CCSS Neurocognitive Questionnaire (NCQ) and the Brief Symptom Inventory-18 (BSI-18) and who provided buccal DNA samples. Real-time polymerase chain reaction (PCR) allelic discrimination was used for SOD2 (rs4880), GPX1 (rs1050450), and GSTP1 (rs1695 and rs1138272) genotyping and PCR for GSTM1 and GSTT1 gene deletions. Outcomes on NCQ and BSI-18 subscale scores were examined in association with genotypes and clinical factors, including age at diagnosis, sex, and radiation dose, using univariate and multivariate analysis of variance. Patients <7 years of age at diagnosis displayed more problems with task efficiency (P < .001) and fewer problems with somatic complaints (P = .004) than did patients ≥7 years of age. Female patients reported more organization problems than did male patients (P = .02). Patients with homozygous GSTM1 gene deletion reported higher anxiety (mean null genotype = 47.3 ± 9.2, non-null = 43.9 ± 7.8; P = .04), more depression (null = 51.0 ± 9.8, non-null = 47.0 ± 9.4; P = .03), and more global distress (null = 50.2 ± 9.7, non-null = 45.2 ± 9.9; P = .01). All associations for the GSTM1 polymorphism remained statistically significant in a multivariate model controlling for age, sex, and radiation dose. Homozygous GSTM1 gene deletion was consistently associated with greater psychological distress in medulloblastoma survivors across multiple domains, suggesting that this genotype may predispose patients for increased emotional late effects.

Opposite effects of GSTM1--and GSTT1: gene deletion variants on bone mineral density.

Oxidative stress is associated with osteoporosis. The glutathione S-transferases form the major detoxifying group of enzymes responsible for eliminating products of oxidative stress. We have therefore proposed GSTM1 and GSTT1 genes as candidates for studying the genetics of osteoporosis.The aim of the present study was to examine possible association of GSTM1 and GSTT1 gene deletion polymorphisms, alone or in combination, with bone mineral density at femoral neck (BMD_fn), lumbar spine (BMD_ls) and total hip (BMD_th) in Slovenian elderly women and men. GSTM1 and GSTT1 gene deletion polymorphisms in 712 elderly people were analyzed using the triplex PCR method for the presence of GSTM1 and GSTT1 gene segments. BMD_fn, BMD_ls and BMD_th were measured by the dual-energy X-ray absorptiometry (DEXA) method. Results were analyzed using univariate statistic model adjusted for sex, body mass index (BMI) and age.Our results showed the significant differences in BMD_th, BMD_ls and BMD_fn values (p = 0.031, 0.017 and 0.023, respectively) in subgroups of GSTT1 gene deletion polymorphism. For GSTM1 gene deletion polymorphism borderline significant association was found with BMD_ls (p = 0.100). Furthermore, subjects with homozygous deletion of GSTT1 gene showed higher BMD values on all measured skeletal sites and, in contrast, subjects with homozygous deletion of GSTM1 gene showed lower BMD values. Moreover, a gene-gene interaction study showed significant association of GSTM1-null and GSTT1-null polymorphisms with BMD_ls values (p = 0.044). Carriers with a combination of the presence of GSTT1 gene and the homozygous absence of GSTM1 gene fragment were associated with the lower BMD values at all skeletal sites.The significant association of combination of GSTT1 gene presence and homozygous absence of GSTM1 gene with BMD was demonstrated, suggesting that it could be used, if validated in other studies, as genetic marker for low BMD.

Mutations in the DNA polymerase and thymidine kinase genes of herpes simplex virus clinical isolates resistant to antiherpetic drugs

Association of deletion polymorphism in GSTT1 and GSTM1 genes and polymorphic variant A313G of GSTP1 gene with cirrhosis diseases and 4-year survival rate for the Tomsk region (West Siberia) patients were tested. Homozygous deletion of GSTM1 gene (null genotype) was a protective factor for alcoholic and mixed (HCV, HBV and alcohol) liver cirrhosis development. The patients from the joint group (all etiology forms) as well as having alcoholic and mixed cirrhosis had lower frequency of GSTM1 null genotype (39.2, 39.0, and 34.2%, respectively) in comparison with the control group (64.6%). The GSTM1 null genotype and GSTP1 gene A313G polymorphic variant correlated with the patients' survival rate. The patients survived in comparison with the dead had higher frequency of a GSTM1 null genotype (46.6 vs. 30.2%) and GSTP1 AA genotype (63.1 vs. 40.5%), and lower frequency of GSTP1 AG (A313G) genotype (31.1 vs. 51.2%). A survival rate was 2.5 times higher for patients having GSTP1 AA genotype in comparison with the GG and AG genotype carriers and 2 times higher for patients having GSTM1 null genotype than the gene carriers. A 4-year fatal case probability was 2.3 times higher among the patients having heterozygous AG GSTP1 genotype in comparison with homozygous AA and GG genotype carriers.