Association of glutathione-S-transferase with patients of type 2 diabetes mellitus with and without nephropathy

A dual-acting aldose reductase inhibitor impedes oxidative and carbonyl stress in tissues of fructose- and streptozotocin-induced rats: comparison with antioxidant stobadine

Inhibiting aldose reductase (ALR2, AR) as well as maintaining a concomitant antioxidant (AO) activity via dual-acting agents may be a rational approach to prevent cellular glucotoxicity and at least delay the progression of diabetes mellitus (DM). This study was aimed at evaluating the dual-acting AR inhibitor (ARI) cemtirestat (CMTI) on tissue oxidative stress (OS) and carbonyl stress (CS) biomarkers in rats exposed to fructose alone (F) or fructose plus streptozotocin (D; type-2 diabetic). D and F rats were either untreated or treated daily with low- or high-dose CMTI, ARI drug epalrestat (EPA) or antioxidant stobadine (STB) for 14 weeks. Malondialdehyde (MDA), glutathione S-transferase (GST), nitric oxide synthase (NOS), and catalase (CAT) were increased in the sciatic nerve of F and D. These increases were attenuated by low doses of CMTI and STB in D, but exacerbated by low-dose EPA and high-dose CMTI in F. STB and CMTI and to a lesser extent EPA improved MDA, protein-carbonyl, GST and CAT in the hearts and lungs of F and D. CMTI and STB were more effective than EPA in improving the increased MDA and protein-carbonyl levels in the kidneys of F and especially D. CMTI ameliorated renal GST inhibition in D. In the lungs, hearts, and kidneys of F and D, the GSH to GSSG ratio decreased and caspase-3 activity increased, but partially resolved with treatments. In conclusion, CMTI with ARI/AO activity may be advantageous in overcoming OS, CS, and their undesirable consequences, with low dose efficacy and limited toxicity, compared to ARI or antioxidant alone.

Protein posttranslational modifications in health and diseases: Functions, regulatory mechanisms, and therapeutic implications

Protein posttranslational modifications (PTMs) refer to the breaking or generation of covalent bonds on the backbones or amino acid side chains of proteins and expand the diversity of proteins, which provides the basis for the emergence of organismal complexity. To date, more than 650 types of protein modifications, such as the most well-known phosphorylation, ubiquitination, glycosylation, methylation, SUMOylation, short-chain and long-chain acylation modifications, redox modifications, and irreversible modifications, have been described, and the inventory is still increasing. By changing the protein conformation, localization, activity, stability, charges, and interactions with other biomolecules, PTMs ultimately alter the phenotypes and biological processes of cells. The homeostasis of protein modifications is important to human health. Abnormal PTMs may cause changes in protein properties and loss of protein functions, which are closely related to the occurrence and development of various diseases. In this review, we systematically introduce the characteristics, regulatory mechanisms, and functions of various PTMs in health and diseases. In addition, the therapeutic prospects in various diseases by targeting PTMs and associated regulatory enzymes are also summarized. This work will deepen the understanding of protein modifications in health and diseases and promote the discovery of diagnostic and prognostic markers and drug targets for diseases.

A Review of Medicinal Plants with Renoprotective Activity in Diabetic Nephropathy Animal Models

Diabetic nephropathy (DN), also recognized as diabetic kidney disease, is a kidney malfunction caused by diabetes mellitus. A possible contributing factor to the onset of DN is hyperglycemia. Poorly regulated hyperglycemia can damage blood vessel clusters in the kidneys, leading to kidney damage. Its treatment is difficult and expensive because its causes are extremely complex and poorly understood. Extracts from medicinal plants can be an alternative treatment for DN. The bioactive content in medicinal plants inhibits the progression of DN. This work explores the renoprotective activity and possible mechanisms of various medicinal plant extracts administered to diabetic animal models. Research articles published from 2011 to 2022 were gathered from several databases including PubMed, Scopus, ProQuest, and ScienceDirect to ensure up-to-date findings. Results showed that medicinal plant extracts ameliorated the progression of DN via the reduction in oxidative stress and suppression of inflammation, advanced glycation end-product formation, cell apoptosis, and tissue injury-related protein expression.

Association of glutathione S-transferases (GSTT1, GSTM1 and GSTP1) genes polymorphisms with nonalcoholic fatty liver disease susceptibility: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

Glutathione S-transferases (GSTs) genes single-nucleotide polymorphisms (SNPs) have been connected with the susceptibility of nonalcoholic fatty liver disease (NAFLD), but with inconsistent results across the current evidences. The present work was schemed to explore the association between GSTs genes polymorphisms and the NAFLD vulnerability via meta-analysis.

METHODS

PubMed, Web of Science, Cochrane Library, China National Knowledge Infrastructure and Wanfang were retrieved for eligible literatures previous to March 10, 2021. The odds ratio (OR) of the dichotomic variables and the standardized mean difference of quantitative variables with corresponding 95% confidence intervals (95%CIs) were computed to evaluate the strength of the associations. The quality of included studies were assessed via using Newcastle-Ottawa Scale (NOS).

RESULTS

In total, 7 case-control studies encompassing 804 NAFLD patients and 1362 disease-free controls in this meta-analysis. Ultimately, this analysis included 6, 5 and 5 studies for GSTM1, GSTT1 and GSTP1 polymorphisms, respectively. The pooled data revealed that the GSTs genes SNPs had conspicuous associations with NAFLD susceptibility: for GSTM1, null versus present, OR = 1.46, 95%CI 1.20 to 1.79, P = .0002; for GSTT1, null versus present, OR = 1.34, 95%CI 1.06 to 1.68, P = .01; for GSTP1, Ile/Val or Val/Val versus Ile/Ile, OR = 1.60, 95%CI 1.23 to 2.09, P = .0005.

CONCLUSION

This work revealed that the GSTM1 null, GSTT1 null and GSTP1-Val genotypes might be related to increased NAFLD susceptibility.

A single injection of pregabalin induces short- and long-term beneficial effects on fear memory and anxiety-like behavior in rats with experimental type-1 diabetes mellitus

Anxiety Disorders and Posttraumatic Stress Disorders (PTSD) associated with type-1 diabetes mellitus (T1DM) are increasingly common comorbidities and the treatment is quite challenging. In that sense, evidence indicates that the anticonvulsant pregabalin is highly effective in treating severe cases of anxiety, as well as PTSD and diabetic neuropathic pain which is also very prevalent in T1DM. Herein, the short- and long-term effects of a single injection of pregabalin on the acquisition of a fear extinction memory and parameters of anxiety in induced-T1DM animals were investigated. For that, we used the contextual fear conditioning (CFC) and elevated plus maze paradigms, respectively. A putative antioxidant activity was also evaluated. Our findings demonstrated that induced-T1DM animals presented greater expression of fear memory, difficulty in extinguishing this fear memory, associated with a more pronounced anxiety-like response. Pregabalin was able to induce a short and long-lasting effect by facilitating the acquisition of the fear extinction memory and inducing a later anxiolytic-like effect. Also, the increased lipid peroxidation levels in the hippocampus and prefrontal cortex of induced-T1DM rats were reduced after pregabalin injection, while the decreased levels of reduced glutathione were increased in the hippocampus. Despite the need for more studies to understand the mechanism of action of pregabalin under these conditions, our data demonstrate for the first time that a single injection of pregabalin in a specific time window was able to improve behavioral parameters in addition to inducing neuroprotective effect. Thus, pregabalin has potential worth exploring for the treatment of PTSD and/or Anxiety associated with T1DM.

The effects of supplementation of Nannochloropsis oculata microalgae on biochemical, inflammatory and antioxidant responses in diabetic rats

Diabetes is accompanied by inflammation and oxidation. Supplementation of anti-inflammatory and antioxidant compounds can prevent the progression of diabetes. This study aimed to investigate the effects of supplementation of Nannochloropsis oculata microalgae (NOM) on the inflammatory and antioxidant responses in diabetic rats. Sixty male rats were divided into six groups as diabetic and non-diabetic rats receiving 0, 10 and 20 mg/kg of body weight of NOM daily for 21 days. Body weight, the serum concentrations of insulin and glucose and the tissue concentrations of interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α), nuclear factor kappa B (NF-κB), interleukin-6 (IL-6), malondialdehyde (MDA), ferric reducing antioxidant power (FRAP), superoxide dismutase (SOD), glutathione peroxidase (GPx) were assessed. The results showed that induction of diabetes significantly reduced the body weight, the serum concentrations of insulin and the tissue concentrations of SOD, FRAP and GPx while increasing the concentrations of glucose, MDA, IL-1β, IL-6, NF-κB and TNF-α. Daily oral administration of NOM (10 and 20 mg/kg) significantly maintained the body weight, the serum concentrations of insulin and the tissue concentrations of SOD, FRAP and GPx while preventing the increase in the concentrations of glucose, MDA, IL-1β and TNF-α. In conclusion, diabetes caused inflammation and oxidation while NOM worked as a natural anti-inflammatory and antioxidant compound.

Redox changes in obesity, metabolic syndrome, and diabetes

"Life is an instantaneous encounter of circulating matter and flowing energy" (Jean Giaja, Serbian physiologist), is one of the most elegant definitions not only of life but the relationship of redox biology and metabolism. Their evolutionary liaison has created inseparable yet dynamic homeostasis in health, which, when disrupted, leads to disease. This interconnection is even more pertinent today, in an era of increasing metabolic diseases of epidemic proportions such as obesity, metabolic syndrome, and diabetes. Despite great advances in understanding the molecular mechanisms of redox and metabolic regulation, we face significant challenges in preventing, diagnosing, and treating metabolic diseases. The etiological association and temporal overlap of these syndromes present significant challenges for the discrimination of appropriate clinical biomarkers for diagnosis, treatment, and outcome prediction. These multifactorial, multiorgan metabolic syndromes with complex etiopathogenic mechanisms are accompanied by disturbed redox equilibrium in target tissues and circulation. Free radicals and reactive species are considered both a causal factor and a consequence of disease status. Thus, determining the subtypes and levels of free radicals and reactive species, oxidatively damaged biomolecules (lipids, proteins, and nucleic acids) and antioxidant defense components as well as redox-sensitive transcription factors and fluxes of redox-dependent metabolic pathways will help define existing and establish novel redox biomarkers for stratifying metabolic diseases. This review aims to discuss diverse redox/metabolic aspects in obesity, metabolic syndrome, and diabetes, with the imperative to help establish a platform for emerging and future redox-metabolic biomarkers research in precision medicine. Future research warrants detailed investigations into the status of redox biomarkers in healthy subjects and patients, including the use of emerging 'omic' profiling technologies (e.g., redox proteomes, lipidomes, metabolomes, and transcriptomes), taking into account the influence of lifestyle (diet, physical activity, sleep, work patterns) as well as circadian ~24h fluctuations in circulatory factors and metabolites.

Diminazene Aceturate Stabilizes Atherosclerotic Plaque and Attenuates Hepatic Steatosis in apoE-Knockout Mice by Influencing Macrophages Polarization and Taurine Biosynthesis

Atherosclerosis and nonalcoholic fatty liver disease are leading causes of morbidity and mortality in the Western countries. The renin-angiotensin system (RAS) with its two main opposing effectors, i.e., angiotensin II (Ang II) and Ang-(1-7), is widely recognized as a major regulator of cardiovascular function and body metabolic processes. Angiotensin-converting enzyme 2 (ACE2) by breaking-down Ang II forms Ang-(1-7) and thus favors Ang-(1-7) actions. Therefore, the aim of our study was to comprehensively evaluate the influence of prolonged treatment with ACE2 activator, diminazene aceturate (DIZE) on the development of atherosclerotic lesions and hepatic steatosis in apoE-/- mice fed a high-fat diet (HFD). We have shown that DIZE stabilized atherosclerotic lesions and attenuated hepatic steatosis in apoE-/- mice fed an HFD. Such effects were associated with decreased total macrophages content and increased α-smooth muscle actin levels in atherosclerotic plaques. Moreover, DIZE changed polarization of macrophages towards increased amount of anti-inflammatory M2 macrophages in the atherosclerotic lesions. Interestingly, the anti-steatotic action of DIZE in the liver was related to the elevated levels of HDL in the plasma, decreased levels of triglycerides, and increased biosynthesis and concentration of taurine in the liver of apoE-/- mice. However, exact molecular mechanisms of both anti-atherosclerotic and anti-steatotic actions of DIZE require further investigations.

Histological and biochemical investigation of the renoprotective effects of metformin in diabetic and prostate cancer model

BACKGROUND

Diabetes and cancer have common physiological and biochemical mechanisms. Metformin is the preferred drug of choice for the treatment of diabetes. Prostate cancer can be modeled in by injection of MAT-Lylu cells. A model of diabetes in rats is induced by streptozotocin injectıon. In the current study, we explored the mechanisms by which diabetes accelerates cancer, and evaluated the effects of metformin to know whether it has any impact against the damage caused by cancer and diabetic + cancer via histopathological and biochemical parameters of kidney tissue.

METHODS

The experiment was carried out in rats. Groups 1-Control, 2- Diabetic, 3-Cancer, 4-Diabetic + cancer, 5-Diabetic + cancer + metformin, 6-Cancer + metformin. Metformin treatment was applied by gavage every day. The research ended on the 14th day. The collected kidney tissue sections were stained with Hematoxylin-Eosin.

RESULTS

Histological evaluation showed moderate to severe damage to the kidney tissue following diabetic and cancer processess. In diabetic, cancer and diabetic + cancer groups, reduced glutathione levels, total antioxidant status, sodium/potassium-ATPase and paraoxonase1 activities were found to be significantly abated. While advanced oxidized protein products, lipid peroxidation, nitric oxide, tumor necrosis factor-alpha, reactive oxygen species levels, total oxidant status, catalase, superoxide dismutase, glutathione-related antioxidant enzymes, myeloperoxidase, and arginase activities were significantly raised. The administration of metformin reversed these defects. The outcome of the reveals that histopathological and biochemical damage in cancer and diabetes + cancer groups decreased in the groups that received metformin.

CONCLUSION

In conclusion, metformin treatment can be considered an adjuvant candidate for kidney tissue in diabetes, prostate cancer and cancer therapy related damage.

Modulation of Renal Function in a Metabolic Syndrome Rat Model by Antioxidants in Hibiscus sabdariffa L

Metabolic syndrome (MS) is the association of three or more pathologies among which obesity, hypertension, insulin resistance, dyslipidemia, and diabetes are included. It causes oxidative stress (OS) and renal dysfunction. Hibiscus sabdariffa L. (HSL) is a source of natural antioxidants that may control the renal damage caused by the MS. The objective of this work was to evaluate the effect of a 2% HSL infusion on renal function in a MS rat model induced by the administration of 30% sucrose in drinking water. 24 male Wistar rats were divided into 3 groups: Control rats, MS rats and MS + HSL rats. MS rats had increased body weight, systolic blood pressure, triglycerides, insulin, HOMA index, and leptin (p ≤ 0.04). Renal function was impaired by an increase in perfusion pressure in the isolated and perfused kidney, albuminuria (p ≤ 0.03), and by a decrease in clearance of creatinine (p ≤ 0.04). The activity of some antioxidant enzymes including the superoxide dismutase isoforms, peroxidases, glutathione peroxidase, glutathione-S-transferase was decreased (p ≤ 0.05). Lipoperoxidation and carbonylation were increased (p ≤ 0.001). The nitrates/nitrites ratio, total antioxidant capacity, glutathione levels and vitamin C were decreased (p ≤ 0.03). The treatment with 2% HSL reversed these alterations. The results suggest that the treatment with 2% HSL infusion protects renal function through its natural antioxidants which favor an improved renal vascular response. The infusion contributes to the increase in the glomerular filtration rate, by promoting an increase in the enzymatic and non-enzymatic antioxidant systems leading to a decrease in OS and reestablishing the normal renal function.

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.

S-glutathionylation, friend or foe in cardiovascular health and disease

Glutathione is a low molecular weight thiol that is present at high levels in the cell. The high levels of glutathione in the cell make it one of the most abundant antioxidants contributing to cellular redox homeostasis. As a general rule, throughout cardiovascular disease and progression there is an imbalance in redox homeostasis characterized by reactive oxygen species overproduction and glutathione underproduction. As research into these imbalances continues, glutathione concentrations are increasingly being observed to drive various physiological and pathological signaling responses. Interestingly in addition to acting directly as an antioxidant, glutathione is capable of post translational modifications (S-glutathionylation) of proteins through both chemical interactions and enzyme mediated events. This review will discuss both the chemical and enzyme-based S-glutathionylation of proteins involved in cardiovascular pathologies and angiogenesis.

Chromium(III) Glycinate Complex Supplementation Improves the Blood Glucose Level and Attenuates the Tissular Copper to Zinc Ratio in Rats with Mild Hyperglycaemia

The aim of the study was to evaluate the hypoglycaemic potential of supplementary Cr in the form of chromium(III) glycinate (CrGly) in the diabetic model of rats. The experiment was conducted on 40 male Wistar rats, of which 30 were made diabetic by injection of a single dose of streptozotocin (55 mg/kg b.m.), while the remaining 10 rats served as the healthy control. After inducing hyperglycaemia, 2 groups of diabetic rats (10 rats each) were supplemented with Cr either as CrGly or chromium(III) picolinate (CrPic) given orally at a dose of 10 mg/kg diet (about 0.75 mg Cr/kg b.m.) with adequate AIN-93M diet for 7 weeks. At the termination of experiment, all animals were sacrificed to collect blood and internal organs for biochemical assays. Blood biochemical indices and tissular trace element contents (Fe, Zn, Cu, Cr) were measured and compared with the values of the untreated groups. It was found that CrGly significantly decreased blood glucose, total cholesterol, HDL cholesterol and triacylglycerol levels more efficiently than CrPic. Furthermore, both Cr compounds normalized disturbed the serum, renal and cardiac molar Cu/Zn ratio, as well as restored the kidney Zn and Cu levels in rats with hyperglycaemia. Supplementary Cr did not increase the tissular Cr levels in diabetic rats. The study confirmed the hypoglycaemic potential of CrGly in the diabetic model of rats.

Genetic polymorphism of drug metabolism enzymes (GSTM1, GSTT1 and GSTP1) in the healthy Malian population

Glutathione S-transferase genes, known to be highly polymorphic, are implicated in the process of phase II metabolism of many substrates, including xenobiotics, anticancer and anti-infective drugs. The detoxification activity is linked to individual genetic makeup. Therefore, the identification of alleles and genotypes in these genes within a population may help to better design genetic susceptibility and pharmacogenetic studies. We performed the present study to establish the frequencies of the GSTM1, GSTT1, and GSTP1 c. 313A > G (rs1695) polymorphisms in 206 individuals of the Malian healthy population. GSTM1 and GSTT1 were genotyped by using multiplex polymerase chain reaction, whereas genotypes of GSTP1 were identified by polymerase chain reaction followed by restriction fragment length polymorphism. The frequencies of GSTM1-null and GSTT1-null genotypes were respectively 24.3 and 41.3%. The observed genotype frequencies for GSTP1 were 25.73% homozygous wild-type AA, 49.03% heterozygous AG and 25.24% homozygous mutant GG. The frequency of GSTP1-A allele was 50.24% versus 49.76% for the GSTP1-G allele. The distribution of these three genes was homogeneous between men and women (p > 0.05). We found no statistical association between the presence of a particular profile of GSTM1 or GSTT1 with the genotypes of GSTP1 (p > 0.05). Nevertheless, we noticed that the majority of the individuals harboring the GSTM1-present or the GSTT1-present harbor also the GSTP1-AG genotype. In addition, the triple genotype GSTM1-present/GSTT1-present/AG was the most frequent with 25.2%. Our findings will facilitate future studies regarding genetic associations of multifactorial diseases and pharmacogenetic, thus opening the way to personalized medicine in our population.

Analysis of the coding sequences of clownfish reveals molecular convergence in the evolution of lifespan

Background

Standard evolutionary theories of aging postulate that reduced extrinsic mortality leads to evolution of longevity. Clownfishes of the genus Amphiprion live in a symbiotic relationship with sea anemones that provide protection from predators. We performed a survey and identified at least two species with a lifespan of over 20 years. Given their small size and ease of captive reproduction, clownfish lend themselves as experimental models of exceptional longevity. To identify genetic correlates of exceptional longevity, we sequenced the transcriptomes of Amphiprion percula and A. clarkii and performed a scan for positively-selected genes (PSGs).

Results

The PSGs that we identified in the last common clownfish ancestor were compared with PSGs detected in long-lived mole rats and short-lived killifishes revealing convergent evolution in processes such as mitochondrial biogenesis. Among individual genes, the Mitochondrial Transcription Termination Factor 1 (MTERF1), was positively-selected in all three clades, whereas the Glutathione S-Transferase Kappa 1 (GSTK1) was under positive selection in two independent clades. For the latter, homology modelling strongly suggested that positive selection targeted enzymatically important residues.

Conclusions

These results indicate that specific pathways were recruited in independent lineages evolving an exceptionally extended or shortened lifespan and point to mito-nuclear balance as a key factor.

Electronic supplementary material

The online version of this article (10.1186/s12862-019-1409-0) contains supplementary material, which is available to authorized users.

Do GST polymorphisms influence in the pathogenesis of diabetic nephropathy?

Diabetic patients often develop Diabetic Nephropathy (DN) despite severe long-lasting hyperglycemia, while others develop DN even under intensive insulin therapy. This indicates that factors other than chronic hyperglycemia may also contribute to the susceptibility to the development of DN. The purpose of this case-control study was to investigate the possible role of GSTM1 and GSTT1 deletion polymorphisms, and Single Nucleotide Polymorphism (SNP), GSTP1 313 A > G (Ile105Val), in DN susceptibility. Multiple logistic regression analysis revealed that the occurrence of GST polymorphisms in the Central Brazilian population was not associated with increased risk of DN. However, the presence GSTT1 null genotype suggest an increase trend in systolic blood pressure and opposite inference was observed for the GSTP1 genotype (Ile⁄Val or Val⁄Val). On the order hand, other studies may clarify the relationship of these polymorphisms with DN and help in the prevention of this disease.

Role of protein carbonylation in diabetes

Diabetes mellitus is a metabolic disease characterized by, among others, elevated blood glucose levels. Hyperglycaemia as well as enhanced levels of glucose-derived reactive metabolites contribute to the development of diabetic complications partly via increased generation of reactive oxygen species (ROS). ROS are not only part of signaling pathways themselves but also lead to carbonylation of particular amino acid side chains by direct metal-catalyzed oxidation. In addition, carbonyl groups can be introduced into proteins indirectly by non-oxidative covalent adduction of reactive carbonyl species generated by the oxidation of lipids or carbohydrates. Both direct and indirect carbonylation mechanisms may affect protein conformation, activity, and function. Herein we introduce the different mechanisms of the carbonylation reaction, discuss degradation mechanisms, and the fate of proteins modified this way and how the overall degree of carbonylation affects protein homeostasis and function differently. The role of protein carbonylation in metabolic control systems and cell signaling are also summarized. Finally, current diagnostic and antioxidant therapeutic options in diabetes are discussed.

Poly(ADP-ribosylated) proteins in mononuclear cells from patients with type 2 diabetes identified by proteomic studies

AIMS

In diabetes, hyperglycemia increases reactive oxygen species that induce DNA damage and poly(ADP-ribose)polymerase activation. The aim of this study is to characterize the proteomic profile and the role of poly(ADP-ribosylation) in patients with type 2 diabetes.

METHODS

A proteomic platform based on 2DE and MALDI-ToF spectrometry was applied to peripheral blood mononuclear cells obtained from two different cohorts in which diabetic (n = 14) and normoglycemic patients (n = 11) were enrolled.

RESULTS

Proteomic maps identified WD repeat protein, 78-kDa glucose-regulated protein precursor and myosin regulatory light chain 2, as unique proteins in diabetic patients; vimentin, elongation factor 2, annexin A1, glutathione S-transferase P, moesin and cofilin-1 as unique in the normoglycemic; and calreticulin, rho GDP-dissociation inhibitor 2, protein disulfide isomerase and tropomyosin alpha-4-chain as differentially expressed between the two cohorts. An enrichment in PARylation in diabetic patients was observed in particular, affecting GAPDH and α-Enolase leading to a decrease in their enzymatic activity.

CONCLUSIONS

As the GAPDH and α-Enolase are involved in energy metabolism, protein synthesis and DNA repair, loss of their function or change in their activity can significantly contribute to the molecular mechanisms responsible for the development of type 2 diabetes. These data along with the proteomic profile associated with the disease may provide new insight into the pathophysiology of type 2 diabetes.

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.

An update on diabetic kidney disease, oxidative stress and antioxidant agents

Diabetes mellitus is a metabolic disease that is defined by relative or absolute deficiency of insulin secretion. Diabetic kidney disease seems to be one of the most frequent complications of diabetes mellitus. Based on evidence, increased free-radical formation and/or diminished antioxidant defenses induce oxidative stress that is implicated in the pathogenesis of diabetic kidney disease. It is evident that diabetic state induces oxidative stress through different signaling pathways as well as reactive oxygen species (ROS) formation that attributes to the activation of various downstream signaling cascade leading to structural the way to structural and functional changes in kidney.