Glutathione-s-transferase M1 and T1 polymorphisms and associations with type 1 diabetes age-at-onset

Distinct transcriptomic profiles in children prior to the appearance of type 1 diabetes-linked islet autoantibodies and following enterovirus infection

Although the genetic basis and pathogenesis of type 1 diabetes have been studied extensively, how host responses to environmental factors might contribute to autoantibody development remains largely unknown. Here, we use longitudinal blood transcriptome sequencing data to characterize host responses in children within 12 months prior to the appearance of type 1 diabetes-linked islet autoantibodies, as well as matched control children. We report that children who present with insulin-specific autoantibodies first have distinct transcriptional profiles from those who develop GADA autoantibodies first. In particular, gene dosage-driven expression of GSTM1 is associated with GADA autoantibody positivity. Moreover, compared with controls, we observe increased monocyte and decreased B cell proportions 9-12 months prior to autoantibody positivity, especially in children who developed antibodies against insulin first. Lastly, we show that control children present transcriptional signatures consistent with robust immune responses to enterovirus infection, whereas children who later developed islet autoimmunity do not. These findings highlight distinct immune-related transcriptomic differences between case and control children prior to case progression to islet autoimmunity and uncover deficient antiviral response in children who later develop islet autoimmunity.

Role of GSTM1 in Hypertension, CKD, and Related Diseases across the Life Span

Over 20 years after the introduction of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, CKD remains a major public health burden with limited therapeutic options to halt or slow kidney disease progression at all ages. The consensus is that oxidative stress contributes to CKD development and progression. Yet, to date, there is no clear evidence that broad use of antioxidant therapy provides a beneficial effect in CKD. Understanding the specific pathophysiologic mechanisms in those who are genetically most susceptible to oxidative stress is a crucial step to inform therapy in an individualized medicine approach, considering differing exposures and risks across the life span. Glutathione-S-transferase μ 1 (GSTM1) is a phase 2 enzyme involved in inactivation of reactive oxygen species and metabolism of xenobiotics. In particular, those with the highly prevalent GSTM1 null genotype (GSTM1[0/0]) may be more susceptible to kidney disease progression, due to impaired capacity to handle the increased oxidative stress burden in disease states, and might specifically benefit from therapy that targets the redox imbalance mediated by loss of the GSTM1 enzyme. In this review, we will discuss the studies implicating the role of GSTM1 deficiency in kidney and related diseases from experimental rodent models to humans, from the prenatal period through senescence, and the potential underlying mechanism.

Urinary Proteome Differences in Canine Diabetes with and without the Presence of Microalbuminuria

Simple Summary

Canine diabetes is a serious disease, which can lead to numerous complications. There are limited data on urine proteomics in dogs, and none of the effect of diabetes mellitus on the urine proteome. In this study we aimed to analyze the protein composition of the urine collected from the healthy animals and compare it with two diabetic groups (normoalbuminuric and microalbuminuric). There are significant differences between these three groups, and we believe that the identified proteins hold promise as a potential diagnostic tool, which can be later on used in clinical practice, and for better understanding of the disease.

Abstract

In this study we aimed to analyze the protein composition of the urine collected from the healthy animals and compare it to the two diabetic groups (DM I normoalbuminuric diabetic dogs; DM II diabetic dogs with microalbuminuria). We tried to identify potential urinary proteins which could be up- or downregulated in diabetic patients even before the appearance of microalbuminuria. Methods: After obtaining urine, we performed two-dimensional electrophoresis, followed by Delta2D software analysis, which allowed for selection and identification with MALDI-TOF spectrometry, statistically significant differentially expressed proteins. Our study revealed 286 common protein spots on 2D gels from the diabetic and control group. From these proteins five were positively identified by MALDI-TOF MS. To further evaluate the five differentiating proteins, the Panther program was used to assign them to appropriate biological process. Conclusion: Significant number of identified proteins play a role in intracellular signaling—vesicle formation, bonding, transport through membranes. This may suggest that first signs of kidney diabetic cellular impairment may be seen in the urine composition before any clinical signs occur.

An updated pharmacological insight of resveratrol in the treatment of diabetic nephropathy

As one of the most common complications of diabetes, nephropathy develops in approximately 40% of diabetic individuals. Although end stage kidney disease is known as one of the most consequences of diabetic nephropathy, the majority of diabetic individuals might die from cardiovascular diseases and infections before renal replacement treatment. Moreover, the routine medical treatments for diabetes hold undesirable side effects. The explosive prevalence of diabetes urges clinicians and scientists to investigate the complementary or alternative therapies. Phytochemicals are emerging as alternatives with a wide range of therapeutic effects on various pathologies, including diabetic kidney disease. Of those phytochemicals, resveratrol, a natural polyphenolic stilbene, has been found to exert a broad spectrum of health benefits via various signaling molecules. In particular, resveratrol has gained a great deal of attention because of its anti-oxidative, anti-inflammatory, anti-diabetic, anti-obesity, cardiovascular-protective, and anti-tumor properties. In the renal system, emerging evidence shows that resveratrol has already been used to ameliorate chronic or acute kidney injury. This review critically summarizes the current findings and molecular mechanisms of resveratrol in diabetic renal damage. In addition, we will discuss the adverse and inconsistent effects of resveratrol in diabetic nephropathy. Although there is increasing evidence that resveratrol affords great potential in diabetic nephropathy therapy, these results should be treated with caution before its clinical translation. In addition, the unfavorable pharmacokinetics and/or pharmacodynamics profiles, such as poor bioavailability, may limit its extensive clinical applications. It is clear that further research is needed to unravel these limitations and improve its efficacy against diabetic nephropathy. Increasing investigation of resveratrol in diabetic kidney disease will not only help us better understand its pharmacological actions, but also provide novel potential targets for therapeutic intervention.

Recombinant glutathione-S-transferase A3 protein regulates the angiogenesis-related genes of erythrocytes in thiram induced tibial lesions

Tibial dyschondroplasia (TD) is a skeletal deformity disease in broilers that occurs when vascularization in the growth plate (GP) is below normal. Although, blood vessels have been reported to contribute significantly in bone formation. Therefore, in the current study, we have examined the mRNA expression of angiogenesis-related genes in erythrocytes of thiram induced TD chickens by qRT-PCR and performed histopathological analysis to determine regulatory effect of recombinant Glutathione-S-Transferase A3 (rGSTA3) protein in response to the destructive effect of thiram following the injection of rGSTA3 protein. Histopathology results suggested that, blood vessels of GPs were damaged in thiram induced TD chicken group (D), it also affected the area and density of blood vessels. In the 20 and 50 μg·kg^-1 of rGSTA3 protein-administered groups, E and F vessels appeared to be normal and improved on day 6 and 15. Furthermore, qRT-PCR results showed that rGSTA3 protein significantly (P < .05) up-regulated the expression of the most important angiogenesis-related integrin family genes ITGA2, ITGA5, ITGB2, ITGB3, ITGAV. The expression level of other genes including TBXA2R, FYN, IQGAP2, IL1R1, GIT1, RAP1B, RPL17, RAC2, MAML3, PTPN11, VAV1, PTCH1, NCOR2, CLU and ITGB3 up-regulated on dosage of rGSTA3 protein. In conclusion, angiogenesis is destroyed in thiram induced TD broilers, and rGSTA3 protein injection improved the vascularization of GPs by upregulating the angiogenesis related genes most importantly integrin family genes ITGAV, ITGA2, ITGB2, ITGB3, ITGA5.

Effect of β-D-Mannuronic Acid (M2000) on Oxidative Stress Enzymes' Gene Using Healthy Donor Peripheral Blood Mononuclear Cells for Evaluating the Anti-Aging Property

OBJECTIVE

This research aimed to study the anti-aging and anti-inflammatory effects of low and high doses of the β-D-mannuronic (M2000) on gene expression of enzymes involved in oxidative stress (including SOD2, GST, GPX1, CAT, iNOS, and MPO) in peripheral blood mononuclear cells (PBMCs) of healthy donors under in vitro conditions.

METHODS

The PBMCs were separated and the RNAs were then extracted and the cDNAs synthesized, and expression levels of the mentioned genes were detected by qRT-PCR.

RESULTS

Our results indicated that the high dose of this drug could significantly reduce the expression level of the SOD2 gene compared to the lipopolysaccharide (LPS) group (p < 0.0001). Moreover, it was found that the high dose of this drug could significantly decrease the expression level of the GST gene compared to the LPS group (p < 0.0001). However, no significant reductions were observed in expression levels of the CAT and GPX1 genes compared to the LPS group. Furthermore, our data revealed that the level of iNOS and MPO gene expression was significantly reduced, in both doses of M2000, respectively, compared to the LPS group (p < 0.0001).

CONCLUSION

This research showed that M2000 as a novel NSAID with immunosuppressive properties could modify oxidative stress through lowering expression levels of the SOD2, GST, iNOS, and MPO genes compared to the healthy expression levels, with a probable reduction of the risk of developing inflammatory diseases related to age and aging.

The Role Of Adiponectin, TNF-α And Glutathione In The Pathogenesis And Evolution Of Type 1 Diabetes

INTRODUCTION

Type 1 diabetes (T1DM) is a chronic autoimmune or idiopathic condition, featuring complex and unique interactions between proteins and enzyme systems. The purpose of the present study is to investigate the role of AdipoQ +276G>T, TNF-α-308G>A, GSTT1/GSTM1 polymorphic variants in the development of T1DM.

MATERIALS AND METHODS

The study is designed as a cross-sectional study, involving 72 diabetic cases and 90 controls. Genotyping was carried out according to specific protocols for the above-mentioned polymorphic variants.

RESULTS

The G allele of AdipoQ was associated with the development of type 1 diabetes (OR 0.577, CI95% 0.336-0.802, p=0.001), similar to the GG and GA genotypes (OR 0.405, CI95% 0.156-0.654, p=0.001 and OR 0.623, CI95% 0.401-0.855, p=0.004). The G allele of TNF-α was marginally associated with the development of type 1 diabetes (OR 0.789, CI95% 0.579-0.956, p=0.005). The presence of the T1 genotype was a strong predictor for type 1 diabetes (OR 3.4, CI95% 1.433-6.243, p<0.001).

CONCLUSION

The results of our study suggest that G alleles of AdipoQ and TNFα act as a protective factor in T1DM, while the T1 allele for GST could be considered a risk factor for the development of Type 1 diabetes in our study group.

Role of glutathione biosynthesis in endothelial dysfunction and fibrosis

Glutathione (GSH) biosynthesis is essential for cellular redox homeostasis and antioxidant defense. The rate-limiting step requires glutamate-cysteine ligase (GCL), which is composed of the catalytic (GCLc) and the modulatory (GCLm) subunits. To evaluate the contribution of GCLc to endothelial function we generated an endothelial-specific Gclc haplo-insufficient mouse model (Gclc e/+ mice). In murine lung endothelial cells (MLEC) derived from these mice we observed a 50% reduction in GCLc levels compared to lung fibroblasts from the same mice. MLEC obtained from haplo-insufficient mice showed significant reduction in GSH levels as well as increased basal and stimulated ROS levels, reduced phosphorylation of eNOS (Ser 1177) and increased eNOS S-glutathionylation, compared to MLEC from wild type (WT) mice. Studies in mesenteric arteries demonstrated impaired endothelium-dependent vasodilation in Gclc(e/+) male mice, which was corrected by pre-incubation with GSH-ethyl-ester and BH4. To study the contribution of endothelial GSH synthesis to renal fibrosis we employed the unilateral ureteral obstruction model in WT and Gclc(e/+) mice. We observed that obstructed kidneys from Gclc(e/+) mice exhibited increased deposition of fibrotic markers and reduced Nrf2 levels. We conclude that the preservation of endothelial GSH biosynthesis is not only critical for endothelial function but also in anti-fibrotic responses.

Measurement of absolute copy number variation of Glutathione S-Transferase M1 gene by digital droplet PCR and association analysis in Tunisian Rheumatoid Arthritis population

BACKGROUND

The investigation of copy number variations (CNVs) analysis of candidate genes is currently an important research area in modulating human diseases. We aimed to quantify CNVs in glutathione S-transferase M1 (GSTM1) gene and determine its genetic contribution in Tunisian rheumatoid arthritis (RA) and its subsets through an innovative technique for quantification.

METHODS

A total of 165 RA cases and 102 healthy controls were included in the study. Using a recently powerful approach of digital droplet PCR (ddPCR), we quantified GSTM1 gene to determine the presence of no, one, or multiple copy number (CN) at high levels of sensitivity and specificity. Odds ratio and Fisher exact test were performed to estimate the association risk for GSTM1CNVs in RA.

RESULTS

Copy number identified by ddPCR was 0, 1, and 2 copies per diploid genome. A high frequency of '0' copy was revealed with 54% in RA patients. The deletion ('0' copy) of GSTM1 was found to be a significant risk factor for anti-cyclic citrullinated peptide (anti-CCP) positive RA (OR=4.16, CI_95% =[1.17-14.7]). In addition, a lack of association was found when comparing between the CNVs of RA patients and those of controls.

CONCLUSION

This study highlights the powerful accuracy of ddPCR for the quantification of CNVs and suggests that the variation in the CN of GSTM1 is associated with anti-CCP positivity in RA. However, it does not indicate a specific role in the susceptibility to the disease in our Tunisian sample.

Gene Polymorphisms of Glutathione S-Transferase T1/M1 in Egyptian Children and Adolescents with Type 1 Diabetes Mellitus

OBJECTIVE

Oxidative stress plays an important role in the pathogenesis of type 1 diabetes mellitus (T1DM). To evaluate the association of glutathione S-transferase mu 1 (GST M1) and glutathione S-transferase theta 1 (GST T1) polymorphisms with development of T1DM and disease-related risk factors.

METHODS

Measurement of fasting glucose, serum creatinine, lipid profile, and glycosylated hemoglobin (HbA1c), as well as evaluation of GST T1 and M1 genetic polymorphisms using polymerase chain reaction were done in 64 diabetic children and 41 controls.

RESULTS

The diabetic group had significantly higher fasting glucose, HbA1c, and cholesterol levels. GST T1 null genotype was more frequent in the diabetic than the control group with 4.2-fold increased risk of T1DM (odds ratio=4.2; 95% confidence interval=1.6-11.5; p=0.03). Significant positive associations were found with lipid profile, HbA1c, and duration of illness but not with age, age at onset, and body mass index.

CONCLUSION

Gene polymorphisms of the enzyme GST are associated with development of T1DM and disease-related risk factors.

The possible role of glutathione-S-transferase activity in diabetic nephropathy

The most common cause of end stage renal disease is diabetic nephropathy. An early diagnosis may allow an intervention to slow down disease progression. Recently, it has been hypothesized that glutathione-S-transferase (GST) activity may be a marker of severity of chronic kidney disease. In particular, a lower GST activity is present in healthy subjects compared to patients with nephropathy. In the present review we illustrate the scientific evidence underlying the possible role of GST activity in the development of diabetic nephropathy and we analyze its usefulness as a possible early biomarker of this diabetic complication.

Polymorphisms of glutathione S-transferase and methylenetetrahydrofolate reductase genes in Moldavian patients with ulcerative colitis: Genotype-phenotype correlation

Background

Glutathione S-transferases (GSTM1, GSTT1, and GSTP1) and methylenetetrahydrofolate reductase (MTHFR) are important enzymes for protection against oxidative stress. In addition, MTHFR has an essential role in DNA synthesis, repair, and methylation. Their polymorphisms have been implicated in the pathogenesis of ulcerative colitis (UC). The aim of the present study was to investigate the role of selected polymorphisms in these genes in the development of UC in the Moldavian population.

Methods

In a case-control study including 128 UC patients and 136 healthy individuals, GSTM1 and GSTT1 genotypes (polymorphic deletions) were determined using multiplex polymerase chain reaction (PCR). The GSTP1 rs1695 (Ile105Val), MTHFR rs1801133 (C677T), and MTHFR rs1801131 (A1298C) polymorphisms were studied with restriction fragment length polymorphism (RFLP) analysis. Genotype–phenotype correlations were examined using logistic regression analysis.

Results

None of the genotypes, either alone or in combination, showed a strong association with UC. The case-only sub-phenotypic association analysis showed an association of the MTHFR rs1801133 polymorphism with the extent of UC under co-dominant (p corrected = 0.040) and recessive (p corrected = 0.020; OR = 0.15; CI = 0.04–0.63) genetic models. Also, an association between the MTHFR rs1801131 polymorphism and the severity of UC was reported for the over-dominant model (p corrected = 0.023; coefficient = 0.32; 95% CI = 0.10–0.54).

Conclusion

The GST and MTHFR genotypes do not seem to be a relevant risk factor for UC in our sample. There was, however, evidence that variants in MTHFR may influence the clinical features in UC patients. Additional larger studies investigating the relationship between GST and MTHFR polymorphisms and UC are required.

Evaluation of glutathione S-transferase T1 deletion polymorphism on type 2 diabetes mellitus risk in Zoroastrian females in Yazd, Iran

BACKGROUND

There has been much interest in the role of free radicals and oxidative stress in the pathogenesis of diabetes mellitus (DM). The aim of this study was to assess the possible association between genetic polymorphisms of the glutathione S-transferase-Theta (GSTT1) and the risk of the development of DM in Zoroastrian females in Yazd, Iran.

MATERIALS AND METHODS

This was a case-control study in which GSTT1 polymorphism was genotyped in 51 randomly selected DM patients and 50 randomly selected healthy controls among Zoroastrian females whose ages ranged from 40 to 70.

RESULTS

The frequencies of GSTT1 null genotype and GSTT1 present were 72% and 28%, respectively, in control samples, while in patients with type 2 diabetes (T2DM), the frequencies of GSTT1 null genotype and GSTT1 present were 27.5% and 72.5%, respectively. There were higher levels of triglyceride (TG), fasting blood sugar (FBS), total cholesterol (TC), low-density lipoprotein (LDL), Urea, and high-density lipoprotein (HDL) in cases of GSTT1 null genotype compared to the GSTT1 present genotype in controls.

CONCLUSIONS

Our results indicated that healthy subjects had a higher frequency of the GSTT1 null genotype than patients with T2DM. However, we observed no significant association between the GSTT1 null genotype and T2DM in the current study.

Association of Glutathione-S-Transferase (GSTM1 and GSTT1) and FTO Gene Polymorphisms with Type 2 Diabetes Mellitus Cases in Northern India

Type 2 diabetes mellitus (T2DM) is growing in an epidemic manner across the world and India has the world's largest number of diabetic subjects. The present study was carried out to investigate the association of glutathione-S-transferase (GSTM1, GSTT1) and fat mass and obesity associated (FTO) gene polymorphisms with T2DM patients and controls, and its role in increasing the susceptibility to T2DM. A total of 198 subjects (101 T2DM patients and 97 controls) participated in this study. GSTM1, GSTT1 and FTO gene polymorphisms in the patients and controls were evaluated by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). We observed significant association of GSTM1 positive (p = 0.046) and GSTM1 null (p = 0.046) genotypes with T2DM, while no significant association was found with the FTO gene polymorphism in our study. It seems that the GSTM1 gene polymorphism can be a predictive marker for early identification of a population at risk of T2DM. The potential role of GST and FTO gene polymorphisms as a marker of susceptibility to T2DM needs further studies in a larger number of patients.

Glutathione S-transferase M1 and glutathione S-transferase T1 genotype in chronic pancreatitis: a meta-analysis

OBJECTIVE

A meta-analysis to determine the association between chronic pancreatitis and glutathione-S transferase (GST) mu 1 (GSTM1) and theta 1 (GSTT1) deletions.

METHODS

Case-control studies concerning the relationship between chronic pancreatitis and GSTM1 or GSTT1 deletions were identified (up to October 2013). Meta-analyses of the association between GSTM1 and GSTT1 genotype and chronic pancreatitis or alcoholic chronic pancreatitis (ACP) were performed.

RESULTS

Seven studies were included in the meta-analysis (650 patients/1382 controls for GSTM1 and 536 patients/1304 controls for GSTT1). There were no significant relationships between GSTM1/GSTT1 and chronic pancreatitis or GSTT1 and ACP. There was a significant association between GSTM1 null genotype and ACP (odds ratio 1.16, 95% confidence intervals 1.03, 1.30).

CONCLUSION

The GSTM1 null genotype was significantly associated with ACP risk.

Genome-wide associations between genetic and epigenetic variation influence mRNA expression and insulin secretion in human pancreatic islets

Genetic and epigenetic mechanisms may interact and together affect biological processes and disease development. However, most previous studies have investigated genetic and epigenetic mechanisms independently, and studies examining their interactions throughout the human genome are lacking. To identify genetic loci that interact with the epigenome, we performed the first genome-wide DNA methylation quantitative trait locus (mQTL) analysis in human pancreatic islets. We related 574,553 single nucleotide polymorphisms (SNPs) with genome-wide DNA methylation data of 468,787 CpG sites targeting 99% of RefSeq genes in islets from 89 donors. We identified 67,438 SNP-CpG pairs in cis, corresponding to 36,783 SNPs (6.4% of tested SNPs) and 11,735 CpG sites (2.5% of tested CpGs), and 2,562 significant SNP-CpG pairs in trans, corresponding to 1,465 SNPs (0.3% of tested SNPs) and 383 CpG sites (0.08% of tested CpGs), showing significant associations after correction for multiple testing. These include reported diabetes loci, e.g. ADCY5, KCNJ11, HLA-DQA1, INS, PDX1 and GRB10. CpGs of significant cis-mQTLs were overrepresented in the gene body and outside of CpG islands. Follow-up analyses further identified mQTLs associated with gene expression and insulin secretion in human islets. Causal inference test (CIT) identified SNP-CpG pairs where DNA methylation in human islets is the potential mediator of the genetic association with gene expression or insulin secretion. Functional analyses further demonstrated that identified candidate genes (GPX7, GSTT1 and SNX19) directly affect key biological processes such as proliferation and apoptosis in pancreatic β-cells. Finally, we found direct correlations between DNA methylation of 22,773 (4.9%) CpGs with mRNA expression of 4,876 genes, where 90% of the correlations were negative when CpGs were located in the region surrounding transcription start site. Our study demonstrates for the first time how genome-wide genetic and epigenetic variation interacts to influence gene expression, islet function and potential diabetes risk in humans.

Inter-individual variation in genetics and epigenetics affects biological processes and disease susceptibility. However, most studies have investigated genetic and epigenetic mechanisms independently and to uncover novel mechanisms affecting disease susceptibility there is a highlighted need to study interactions between these factors on a genome-wide scale. To identify novel loci affecting islet function and potentially diabetes, we performed the first genome-wide methylation quantitative trait locus (mQTL) analysis in human pancreatic islets including DNA methylation of 468,787 CpG sites located throughout the genome. Our results showed that DNA methylation of 11,735 CpGs in 4,504 unique genes is regulated by genetic factors located in cis (67,438 SNP-CpG pairs). Furthermore, significant mQTLs cover previously reported diabetes loci including KCNJ11, INS, HLA, PDX1 and GRB10. We also found mQTLs associated with gene expression and insulin secretion in human islets. By performing causality inference tests (CIT), we identified CpGs where DNA methylation potentially mediates the genetic impact on gene expression and insulin secretion. Our functional follow-up experiments further demonstrated that identified mQTLs/genes (GPX7, GSTT1 and SNX19) directly affect pancreatic β-cell function. Together, our study provides a detailed map of genome-wide associations between genetic and epigenetic variation, which affect gene expression and insulin secretion in human pancreatic islets.

Evaluation of Glutathione S-transferase T1 (GSTT1) deletion polymorphism on type 2 diabetes mellitus risk in a sample of Yazdian females in Yazd, Iran

Background:

There has been much interest in the role of free radicals and oxidative stress in the pathogenesis of diabetes mellitus (DM). The aim of this study was to assess the possible association between genetic polymorphisms of the glutathione S-transferase-mu (GSTT1) and the risk of the development of DM in a sample of Yazdian females in Yazd, Iran.

Methods:

This was a case-control study in which GSTT1 polymorphism was genotyped in 51 randomly selected DM patients and 50 randomly selected healthy controls among Yazdian females whose ages ranged from 40 to 70.

Results:

The frequencies of GSTT1 null genotype and GSTT1 present were 8 and 92%, respectively, in the control samples. In patients with type 2 diabetes (T2DM), the frequencies of GSTT1 null genotype and GSTT1 present were 14 and 86%, respectively. There were higher levels of triglycerides (TG), fasting blood sugar (FBS), total cholesterol (TC), low density lipoprotein (LDL), body mass index (BMI), and high density lipoprotein (HDL) in patients with GSTT1 null genotype than in patients with the GSTT1 present genotype.

Conclusions:

Our results indicated that the GSTT1 deletion polymorphism is a risk factor for T2DM. We did not determine any significant association between the GSTT1 null genotype and T2DM.

Activities of three erythrocyte enzymes of hyperglycemic rats (Rattus norvegicus) treated with Allium sativa extract

Background

The present study sought to investigate erythrocyte glutathione S-transferases (GST), NADH-Methaemoglobin reductase (NADH-MR) and Na⁺/K⁺-ATPase activities of hypoglycemic rats treated with ethanol/water (1:2 v/v) extract of A. sativa as agent of glycemic control.

Methods

Hyperglycemia was induced by a single intra-peritoneal injection of 0.1 mol/L alloxan monohydrate in phosphate buffer saline (PBS) solution (pH = 7.4); dosage = 140 mg/kg. At the end of the experimental time (t = 76 h), erythrocyte GST, NADH-MR and Na⁺/K⁺-ATPase activities as well as serum fasting blood sugar (FBS) levels were measured by spectrophotometric methods.

Results

Serum FBS levels of control/normal (C/N) rats ranged between 72.93 ± 0.82–95.12 ± 0.92 mg/dL, whereas experimental rats without glycemic control gave: 249.41 ± 1.03–256.11 ± 1.23 mg/dL. Hyperglycemic rats treated with ethanol/water (1:2 v/v) extract of A. sativa exhibited comparative reduced serum levels of FBS alongside with erythrocyte GST, NADH-MR and Na⁺/K⁺-ATPase activities. The average relative activities of the three enzymes and corresponding order of enzyme activity in hyperglycemic rats treated with ethanol/water (1:2 v/v) extract of A. sativa was: NADH-MR = 60.99% > GST = 47.81% > Na⁺/K⁺-ATPase = 46.81%. In the same order, relative activities of the three enzymes in rats without glycemic control were: NADH-MR = 49.65% > GST = 23.69% > Na⁺/K⁺-ATPase = 17.02%.

Conclusion

Erythrocyte GST, NADH-MR and Na⁺/K⁺-ATPase activities gave insights into the pathophysiology of diabetic state and served as biomarkers for ascertaining therapeutic control in Type 1 diabetes mellitus.

Resveratrol attenuates early diabetic nephropathy by down-regulating glutathione s-transferases Mu in diabetic rats

Diabetic nephropathy (DN) is the major cause of end-stage renal disease. Resveratrol has been shown to ameliorate hyperglycemia in diabetic rats. However, the effects of resveratrol on DN remain unknown. The aim of the present study is to investigate the effects of resveratrol on early-stage DN. Diabetes was induced by streptozotocin injection in male Wistar rats. The diabetic rats were treated with resveratrol at a dose of 20 mg/kg body weight for 8 weeks. Plasma glucose, creatinine, kidney/body weight ratio, and 24-h urinary protein were determined. The renal pathological changes were examined with periodic acid Schiff staining, and renal mesangial cells were cultured in high glucose concentrations with indicated concentrations of resveratrol (2.5, 5.0, and 10.0 μmol/L). The proliferation of mesangial cells was evaluated by methylthiazoletetrazolium assay. Expressions of glutathione S-transferases Mu (GSTM) and nuclear factor erythroid 2-related factor 2 (Nrf2) were detected by western blot, and apoptosis was analyzed using a flow cytometer. Resveratrol reduced plasma glucose, creatinine, and urinary protein excretion, and attenuated renal hypertrophy. Moreover, resveratrol also reduced the expression of GSTM in diabetic rats. In vitro, resveratrol inhibited the proliferation of mesangial cells caused by high glucose and down-regulated GSTM and Nrf2 expressions in a dose-dependent manner. These findings suggest that resveratrol help prevent the progression of DN. The renoprotection by resveratrol is in part mediated through the inhibition of high glucose-induced rat mesangial cell proliferation and downregulation of GSTM expression.

Investigating GSTT1 and GSTM1 null genotype as the risk factor of diabetes type 2 retinopathy

Background

Diabetes is one of the multifactorial disorders with genetics and environmental factors playing important role in its cause. In diabetes, the defects in cellular metabolism results in increasing free radicals. These radicals react with other vital cellular molecules which are responsible in diabetes side effects. Human glutathione S-transferases (GST) are a family of enzymes that catalyses conjugation of electrophilic substances with glutathione. In this research the deletion of two of the most important genes of this family; GSTT1 and GSTM1 genes was investigated as the risk factor for diabetes mellitus type II and one of its most important complications; retinopathy.

Material and methods

In this study deletion of GSTT1 and GSTM1 genes in 57 diabetics’ patients with retinopathy and 58 diabetic peoples without retinopathy was examined. DNA was extracted from peripheral blood and then multiplex PCR was performed following agarose gel electrophoresis to detect GSTT1 and GSTM1 null genotypes. Data were analyzed with SPSS v16 software.

Results

The results indicated that there was significant relationship between GSTM1 null genotype with retinopathy side effect of diabetes type 2. While there was no significant relationship between GSTT1 null genotypes with retinopathy in diabetes type 2.

Conclusion

Significant correlation between GSTM1 null genotype and retinopathy in this and other studies could indicate this fact that impair cellular metabolism result in increase free radicals and oxidative pressure. Therefore, GST null genotypes may result in decrease antioxidant capacity which causes side effects of diabetes. Considering the performance of different classes of GST null genotypes additional studies are required to confirm this study.

Electronic supplementary material

The online version of this article (doi:10.1186/2251-6581-12-48) contains supplementary material, which is available to authorized users.

Omentin serum levels and omentin gene Val109Asp polymorphism in patients with psoriasis

BACKGROUND

Psoriasis is a chronic inflammatory disease of uncertain pathogenesis. Omentin is a new adipokine with anti-inflammatory properties; however, the relationship between psoriasis and omentin has not been fully established yet.

OBJECTIVES

This study was designed to evaluate the relationship between psoriasis and omentin serum levels and Val109Asp polymorphism in exon 4 of the omentin gene.

METHODS

Forty-nine patients with plaque-type psoriasis and 39 healthy subjects were included in the study. Omentin concentrations were determined by using enzyme-linked immunosorbent assay. Val109Asp polymorphism in exon 4 of the omentin gene was assessed by the polymerase chain reaction-restriction fragment length polymorphism method. Genotypes were determined according to the bands formed in agarose electrophoresis gels. In the statistical analysis, the level of significance was set at P < 0.05.

RESULTS

The serum omentin levels of the patients with psoriasis (354.2 ± 152.0) were found to be significantly lower than those in the control group (488.7 ± 190.3) (P = 0.001). A moderate level negative correlation was determined between serum omentin level and body mass index and waist circumference. No significant differences were observed between the patient and control groups in terms of the genotype and allele frequency of Val109Asp polymorphism in exon 4 of the omentin gene (P > 0.05).

CONCLUSIONS

Omentin serum levels were determined to be low in patients with psoriasis. No significant difference was found regarding Val109Asp polymorphism of the omentin gene. To the best of our knowledge, our study is the first clinical study to examine the relationship between psoriasis and omentin in terms of serum and genomic levels.

The association between gene polymorphisms of glutathione S-transferase T1/M1 and type 1 diabetes in Slovak children and adolescents

BACKGROUND

Considering a dramatic increase in the incidence of type 1 diabetes (T1D) worldwide, current research focuses on complex etiology of T1D where immune system, environmental and genetic factors play a significant role. Glutathione S-transferase family of enzymes protects tissue from oxidative damage which is discussed in the context of T1D. The aim of the study was to investigate an association of glutathione S-transferase mu 1 (GST M1) and glutathione S-transferase theta 1 (GST T1) polymorphisms with type 1 diabetes.

METHODS

163 children, 116 with type 1 diabetes and 47 healthy controls, at the age 6-19 years were enrolled to the study. Basic anthropometric, biochemical parameters and GST T1 diabetes and M1 polymorphisms were established in each subject.

RESULTS

Subjects with T1D had significantly lower concentration of uric acid compared to the healthy subjects (212.85 +/- 57.10 micromol/l vs. 269.57 +/- 72.53; p < 0.001). GST T1 null genotype was more frequent in patients with diabetes compared to the healthy controls (36.2% vs. 21.3%) and represented 2.1-fold increased risk of T1D of borderline statistical significance (OR = 2.1; 95% Cl = 0.949-4.648; p = 0.06). GST T1 null/M1 wild genotype combination was more frequent in patients with diabetes (25.9% vs. 10.6%) and represented 2.9-fold increased risk for T1D development (OR = 2.93; 95% CI = 1.061-8.095; p = 0.032).

CONCLUSION

The study indicates that GST T1 null genotype and GST T1 null/M1 wild combination could be considered a risk factor for type 1 diabetes development in Slovak children and adolescents.

Antioxidant potential of zinc-flavonol complex studied in streptozotocin-diabetic rats

BACKGROUND

Diabetic oxidative stress coexists with a reduction in the antioxidant status, which can further increase the deleterious effects of free radicals. Zinc is an essential trace element with significant antidiabetic activity. However, the acceptance of zinc compounds as promising therapeutic antidiabetic agents has been slowed due to concerns regarding chronic toxicity. Recently, we have designed, synthesized and characterized a novel zinc-flavonol complex and evaluated its antidiabetic efficacy in streptozotocin (STZ)-diabetic rats. The aim of the present study was to evaluate the role of the zinc-flavonol complex in the antioxidant status of diabetic rats.

METHODS

Diabetes was induced in rats by i.p. injection of STZ. Diabetic rats were then treated with the zinc-flavonol complex (5 mg/kg, p.o.) for 30 days. The extent of oxidative stress was assessed by determining lipid peroxide levels, pancreatic tissue antioxidant enzyme activities and plasma concentrations of non-enzymatic antioxidants. In addition, nuclear levels of nuclear factor (NF)-κB p65, pancreatic nitric oxide (NO), and plasma levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were determined. Pancreatic tissues were examined histologically.

RESULTS

Oral treatment with the zinc-flavonol complex significantly improved antioxidant levels and alleviated levels of oxidative stress markers. Furthermore, significant increases were seen in NF-κB p65, NO, TNF-α, IL-1β and IL-6 levels. Histological observations revealed that the zinc-flavonol complex effectively protects pancreatic β-cells against oxidative damage.

CONCLUSION

  The results of the present study indicate that the zinc-flavonol complex has an antioxidative and anti-inflammatory role in the diabetic milieu.

Null genotypes of GSTM1 and GSTT1 contribute to increased risk of diabetes mellitus: a meta-analysis

Diabetes mellitus (DM) is a common disease which results from various causes including genetic and environmental factors. Glutathione S-Transferase M1 (GSTM1) and Glutathione S-Transferase T1 (GSTT1) genes are polymorphic in human and the null genotypes lead to the absence of enzyme function. Many studies assessed the associations between GSTM1/GSTT1 null genotypes and DM risk but reported conflicting results. In order to get a more precise estimate of the associations of GSTM1/GSTT1 null genotypes with DM risk, we performed this meta-analysis. Published literature from PubMed, Embase and China Biology Medicine (CBM) databases was searched for eligible studies. Pooled odds ratios (OR) and corresponding 95% confidence intervals (95%CI) were calculated using a fixed- or random-effects model. 11 publications (a total of 2577 cases and 4572 controls) were finally included into this meta-analysis. Meta-analyses indicated that null genotypes of GSTM1/GSTT1 and dual null genotype of GSTM1-GSTT1 were all associated with increased risk of DM (GSTM1: OR random-effects=1.60, 95%CI 1.10-2.34, POR=0.014; GSTT1: OR random-effects=1.47, 95%CI 1.12-1.92, POR=0.005; GSTM1-GSTT1: OR fixed-effects=1.83, 95%CI 1.30-2.59, POR=0.001). Subgroup by ethnicity suggested significant associations between null genotypes of GSTM1 and GSTT1 and DM risk among Asians (GSTM1: OR random-effects=1.77, 95%CI 1.24-2.53, POR=0.002; GSTT1: OR random-effects=1.58, 95%CI 1.09-2.27, POR=0.015). This meta-analysis suggests null genotypes of GSTM1/GSTT1 and dual null genotype of GSTM1-GSTT1 are all associated with increased risk of DM, and null genotypes of GSTM1/GSTT1 and dual null genotype of GSTM1-GSTT1 are potential biomarkers of DM.

The association between glutathione S-transferase T1 and M1 gene polymorphisms and cardiovascular autonomic neuropathy in Slovak adolescents with type 1 diabetes mellitus

Glutathione S-transferase (GST), as antioxidant enzyme, protects tissue from oxidative damage typical for many pathologic conditions as type 1 diabetes (T1D) and its chronic complications. The aim of the study was to compare the prevalence of GST T1/M1 gene polymorphisms between diabetic adolescents with (CAN+) and without (CAN-) cardiovascular autonomic neuropathy. Forty-six subjects with T1D at the age 15-19 years were enrolled. CAN was diagnosed in 19 patients (41.3%) based on standard cardiovascular tests. GST M1 null genotype was more prevalent in CAN+subjects but this was not statistically significant (OR=1.889, 0.61-6.55, p>0.05). GST T1 wild genotype nearly 5-fold increased the risk of CAN (OR=4.952, 1.13-21.739, p<0.05). Regarding genotype combination, GST T1/M1 wild/null genotype was significantly more frequent in CAN+compared to the CAN- subjects (OR=3.96, 1.024-15.302, p<0.05). No significant difference was found in any biochemical parameters between CAN+and CAN- subgroups. Multivariable logistic regression showed that none of the biochemical parameters estimated was considered a risk factor for CAN, however GST T1 wild and GST T1/M1 wild/null represented a risk factor for CAN development (OR=2.227, 1.079-4.587, p<0.05 and OR=1.990, 1.026-3.859, p<0.05, respectively). GST T1 wild allele and GST T1/M1 wild/null genotype can be considered as risk factors for CAN in Slovak adolescents with T1D.

Pseudoexfoliation syndrome, a systemic disorder with ocular manifestations

Pseudoexfoliation syndrome (PXS) is a systemic condition with eye manifestations. In the eye, pseudoexfoliation material deposits on various structures of the anterior segment. The nature of this material is mostly fibrillar with fibers made up of microfibrils and coated with amorphous material. The composition of these fibrils is diverse and includes basement membrane components as well as enzymes involved in extracellular matrix maintenance. Pseudoexfoliation is the most common cause of secondary open-angle glaucoma (pseudoexfoliation glaucoma, PXG) worldwide. The goal of this review is to summarize our knowledge on the genetics of this systemic disorder and its resultant ocular manifestations. PXS familial aggregation suggests genetic inheritance. PXS has been strongly associated with single nucleotide polymorphisms (SNPs) of the lysyl oxidase-like 1 (LOXL1) gene on chromosome 15q24.1. Two of these SNPs confer a higher than 99% population attributable risk for PXS and PXG in the Nordic population; however, they carry different risks in different populations. The high risk haplotypes also vary among different populations. LOXL1 is one of group of the enzymes involved in the cross-linking of collagen and elastin in the extracellular matrix. Its function in connective tissue maintenance has been confirmed in mice; however, its actual role in PXS remains unclear. Contactin-associated protein-like 2 also has a strong genetic association with PXS in a German cohort and is an attractive candidate molecule. It encodes for a protein involved in potassium channel trafficking. Other candidate genes linked to PXS include lysosomal trafficking regulator, clusterin, adenosine receptors, matrix metalloproteinase-1 (MMP1), and glutathione transferase. These genes may be modifying genes for development of PXS and PXG.

Antidiabetic and antioxidant effect of Semecarpus anacardium Linn. nut milk extract in a high-fat diet STZ-induced type 2 diabetic rat model

Semecarpus anacardium commonly known as marking nut has been used in the Siddha system of medicine against various ailments. The antidiabetic and antioxidant potential of the drug was evaluated in Type 2 diabetic rats induced by feeding a high-fat diet (HFD) for 2 weeks followed by single intraperitoneal injection of streptozotocin (STZ) 35 mg/kg body weight. Three days after STZ induction, the hyperglycemic rats were treated with Semecarpus anacardium nut milk extract (SA) orally at a dosage of 200 mg/kg body weight daily for 30 days. Metformin (500 mg/kg body weight, orally) was used as a reference drug. The fasting blood glucose, insulin, Hb, HbA1c levels, and HOMA-IR and HOMA-β were measured, and also the levels of lipid peroxidation and antioxidant enzymes were observed. SA significantly (p < .05) reduced and normalized blood glucose levels and also decreased the levels of HbA1c as compared with that of HFD STZ control group. SA treatment also significantly (p < .05) increased the levels of antioxidant enzymes while decreasing the levels of lipid peroxidation. The potential antihyperglycemic action and antioxidant role might be due to the presence of flavonoids in the drug.

Antihyperglycemic and antioxidant effects of a flavanone, naringenin, in streptozotocin-nicotinamide-induced experimental diabetic rats

In the present study, the putative antihyperglycemic and antioxidant effects of a flavanone, naringenin, were evaluated in comparison with those of glyclazide, a standard drug for therapy of diabetes mellitus. Diabetes was induced experimentally in 12-h-fasted rats by intraperitoneal injections of first streptozotocin (50 mg/kg b.w.) and then of nicotinamide (110 mg/kg b.w.) after a 15-min interval. Untreated diabetic rats revealed the following in comparison with normal rats: significantly higher mean levels of blood glucose and glycosylated hemoglobin, significantly lower mean levels of serum insulin, significantly lower mean activities of pancreatic antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase), significantly lower mean levels of plasma non-enzymatic antioxidants (reduced glutathione, vitamin C , vitamin E), significantly elevated mean levels of pancreatic malondialdehyde (MDA) and significantly elevated mean activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH). Following oral administration of naringenin (50 mg/kg b.w./day) to diabetic rats for 21 days, the following observations were made in comparison with untreated diabetic rats: significantly lower mean levels of fasting blood glucose and glycosylated hemoglobin, significantly elevated serum insulin levels, significantly higher mean activities of pancreatic enzymatic antioxidants, significantly higher mean levels of plasma non-enzymatic antioxidants, lower mean pancreatic tissue levels of MDA and lower mean activities of ALT, AST, ALP and LDH in serum. The values obtained in the naringenin-treated animals approximated those observed in glyclazide-treated animals. Histopathological studies appeared to suggest a protective effect of naringenin on the pancreatic tissue in diabetic rats. These results suggest that naringenin exhibits antihyperglycemic and antioxidant effects in experimental diabetic rats.

Genetic and Molecular Basis of QTL of Diabetes in Mouse: Genes and Polymorphisms

A systematic study has been conducted of all available reports in PubMed and OMIM (Online Mendelian Inheritance in Man) to examine the genetic and molecular basis of quantitative genetic loci (QTL) of diabetes with the main focus on genes and polymorphisms. The major question is, What can the QTL tell us? Specifically, we want to know whether those genome regions differ from other regions in terms of genes relevant to diabetes. Which genes are within those QTL regions, and, among them, which genes have already been linked to diabetes? whether more polymorphisms have been associated with diabetes in the QTL regions than in the non-QTL regions.

Our search revealed a total of 9038 genes from 26 type 1 diabetes QTL, which cover 667,096,006 bp of the mouse genomic sequence. On one hand, a large number of candidate genes are in each of these QTL; on the other hand, we found that some obvious candidate genes of QTL have not yet been investigated. Thus, the comprehensive search of candidate genes for known QTL may provide unexpected benefit for identifying QTL genes for diabetes.

Effects of GSTM1 in rheumatoid arthritis; results from the Swedish EIRA study

Objective

Glutathione-S-transferases (GSTs) play an important role in tobacco smoke detoxification, interestingly approximately 50% of individuals in most human populations lack the gene GSTM1 due to copy number variation (CNV). We aimed to investigate GSTM1 CNV in Rheumatoid Arthritis (RA) in relation to smoking and HLA-DRB1 shared epitope; the two best known risk factors for RA and in addition, to perform subanalyses in patients where relations between variations in GSTM1 and RA have previously been described.

Methods

qPCR was performed using TaqMan Copy Number assays (Applied Biosystems) for 2426 incident RA cases and 1257 controls from the Swedish EIRA. Odds ratio (OR) together with 95% confidence intervals (CI) was calculated and used as a measure of the relative risk of developing RA.

Results

No association between RA and GSTM1 CNV was observed when analyzing whole EIRA. However, ≥1 copy of GSTM1 appears to be a significant risk factor for autoantibody positive RA in non-smoking females ≥60 years (OR: 2.00 95% CI: 1.07–3.74), a population where such relationships have previously been described. Our data further suggest a protective effect of GSTM1 in ACPA-negative smoking men (OR: 0.56 95% CI: 0.35–0.90).

Conclusion

We assessed the exact number of GSTM1 gene copies in relation to development and severity of RA. Our data provide support for the notion that variations in copy numbers of GSTM1 may influence risk in certain subsets of RA, but do not support a role for GSTM1 CNV as a factor that more generally modifies the influence of smoking on RA.

Ameliorative potential of resveratrol on proinflammatory cytokines, hyperglycemia mediated oxidative stress, and pancreatic beta-cell dysfunction in streptozotocin-nicotinamide-induced diabetic rats

Chronic exposure of pancreatic beta-cells to supraphysiologic glucose causes adverse beta-cell dysfunction. Thus, the present study was aimed to investigate the hypothesis that oral administration of resveratrol attenuates hyperglycemia, proinflammatory cytokines and antioxidant competence and protects beta-cell ultrastructure in streptozotocin-nicotinamide-induced diabetic rats. Oral administration of resveratrol (5 mg/kg body weight) to diabetic rats for 30 days showed a significant decline in the levels of blood glucose, glycosylated hemoglobin (HbA1c), TNF-alpha, IL-1beta, IL-6, NF-kappaB p65 unit and nitric oxide (NO) with concomitant elevation in plasma insulin. Further, resveratrol treated diabetic rats elicited a notable attenuation in the levels of lipid peroxides, hydroperoxides and protein carbonyls in both plasma and pancreatic tissues. The diminished activities of pancreatic superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and glutathione-S-transferase (GST) as well as the decreased levels of plasma ceruloplasmin, vitamin C, vitamin E and reduced glutathione (GSH) in diabetic rats were reverted to near normalcy by resveratrol administration. Based on histological and ultrastructural observations, it is first-time reported that the oral administration of resveratrol may effectively rescue beta-cells from oxidative damage without affecting their function and structural integrity. The results of the present investigation demonstrated that resveratrol exhibits significant antidiabetic potential by attenuating hyperglycemia, enhancing insulin secretion and antioxidant competence in pancreatic beta-cells of diabetic rats.

Similarities in features of autism and asthma and a possible link to acetaminophen use

Autism and autism spectrum disorders are enigmatic conditions that have their origins in the interaction of genes and environmental factors. In this hypothesis, genes statistically associated with autism are emphasized to be important in inflammation and in innate immune pathways, including pathways for susceptibility to asthma. The role of acetaminophen (paracetamol) in an increased risk for asthma is described and a possible similar link to an increased risk for autism is suggested.

Genetic polymorphisms in genes encoding antioxidant enzymes are associated with diabetic retinopathy in type 1 diabetes

OBJECTIVE

Oxidative stress plays an important role in the development of microangiopathic complications in type 1 diabetes. We investigated polymorphic markers in genes encoding enzymes regulating production of reactive oxygen species in association with diabetic retinopathy or diabetic nephropathy.

RESEARCH DESIGN AND METHODS

A total of 124 patients with type 1 diabetes were investigated in this case-control study. All subjects were matched for sex, age, and duration of diabetes. Genotyping was conducted using real-time PCR for p.Val16Ala polymorphism in the MnSOD gene and c.C-262T in the promoter region of the CAT gene. Multiplex PCR method was used for determination of GSTM1 and GSTT1 polymorphic deletions. Fluorescence-labeled PCR amplicons and fragment analysis was used for assessing the number of pentanucleotide (CCTTT)n repeats in inducible nitric oxide synthase.

RESULTS

A positive association of MnSOD genotype Val/Val (odds ratio [OR] 2.49, 95% CI 1.00-6.16, P = 0.045) and GSTM1-1 genotype (2.63, 1.07-6.47, P = 0.031) with diabetic retinopathy but not with diabetic nephropathy was demonstrated. Additionally, the combination of the two genotypes conveyed an even higher risk (4.24, 1.37-13.40, P = 0.009). No other investigated genetic polymorphisms were associated with either diabetic retinopathy or diabetic nephropathy.

CONCLUSIONS

Selected polymorphisms in genes encoding MnSOD and GSTM1 could be added to a panel of genetic markers for identification of individuals with type 1 diabetes at an increased risk for developing diabetic retinopathy.

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.

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.

Contribution of the N-acetyltransferase 2 polymorphism NAT2*6A to age-related hearing impairment

BACKGROUND

Age-related hearing impairment (ARHI) is the most common sensory impairment in older people, affecting 50% of those aged 80 years. The proportion of older people is increasing in the general population, and as a consequence, the number of people affected with ARHI is growing. ARHI is a complex disorder, with both environmental and genetic factors contributing to the disease. The first studies to elucidate these genetic factors were recently performed, resulting in the identification of the first two susceptibility genes for ARHI, NAT2 and KCNQ4.

METHODS

In the present study, the association between ARHI and polymorphisms in genes that contribute to the defence against reactive oxygen species, including GSTT1, GSTM1 and NAT2, was tested. Samples originated from seven different countries and were combined into two test population samples, the general European population and the Finnish population. Two distinct phenotypes for ARHI were studied, Z(low) and Z(high), representing hearing in the low and high frequencies, respectively. Statistical analysis was performed for single polymorphisms (GSTM1, GSTT1, NAT2*5A, NAT2*6A, and NAT2*7A), haplotypes, and gene-environment and gene-gene interactions.

RESULTS

We found an association between ARHI and GSTT1 and GSTM1 in the Finnish population sample, and with NAT2*6A in the general European population sample. The latter finding replicates previously published data.

CONCLUSION

As replication is considered the ultimate proof of true associations in the study of complex disorders, this study provides further support for the involvement of NAT2*6A in ARHI.