Browsing by Author "Pljesa, Steva (6603281733)"

Purpose: We aimed to discern the role of glutathione (GSH) associated enzymes in maintaining high GSH levels in renal cell carcinoma (RCC) of the clear cell type and analyze RCC enzyme antioxidant capacity. Since changes in cellular redox balance in RCC might also be related to alterations of glutathione S-transferase (GST) phenotype, GST class α and π expression was also explored. Methods and materials: Human kidney specimens of tumor and distant nontumor regions were obtained from 15 patients with RCC at the time of surgery. The activities of GSH-replenishing enzymes, γ-glutamylcysteine synthetase (γ-GCS), γ-glutamyl transferase (γ-GT), and glutathione reductase (GR), as well as the activities of antioxidant enzymes glutathione peroxidase (GPX) and catalase (CAT) were determined spectrophotometrically. GST α and π class expression was determined by immunoblot. Results: In the course of renal cancerization, significant changes appear in the activities of GSH-replenishing and antioxidant enzymes. The activity of the key enzyme of GSH synthesis, γ-GCS, is up-regulated (P < 0.001), while the activities of γ-GT and GR are down-regulated in renal tumors compared to nontumor tissue (P < 0.001 and P < 0.05, respectively). Activities of GPX and CAT were also down-regulated (P < 0.001 and P < 0.05, respectively) in RCC. Changes in enzyme antioxidant capacity in RCC were associated with decreased GST class α (P < 0.001) and unchanged GST π expression at the protein level. Conclusions: Changes in redox status in RCC as a consequence of decreased enzyme antioxidant capacity, together with altered GST α expression, may be important factors in development and tumor growth. The up-regulation of γ-GCS and high levels of GSH in RCC may be an attempt to limit injury caused by oxidative stress. © 2008 Elsevier Inc. All rights reserved.

Background: The presence of glutathione transferase (GST) M1 null genotype (GSTM1-null) in end-stage renal disease (ESRD) patients is associated with lower overall survival rate in comparison to those with GSTM1-active variants. We examined association between GSTM1 and GSTT1 deletion polymorphisms as well as SNPs in GSTA1/rs3957357 and GSTP1/rs1695 genes with overall and cause-specific cardiovascular mortality in ESRD patients. Methods. Total of 199 patients undergoing hemodialysis were included in the study. Median value of time elapsed from dialysis initiation until the death, or the end of follow-up was 8 ± 5 years. The effect of GSTM1, GSTT1, GSTP1 and GSTA1 gene polymorphisms on predicting overall and specific cardiovascular outcomes (myocardial infarction, MI or stroke) was analyzed using Cox regression model, and differences in survival were determined by Kaplan-Meier. Results: GSTM1-null genotype in ESRD patients was found to be independent predictor of overall and cardiovascular mortality. However, after false discovery rate and Bonferroni corrections this effect was lost. The borderline effect modification by wild-type GSTA1*A/*A genotype on associations between GSTM1-null and analyzed outcomes was found only for death from stroke. Homozygous carriers of combined GSTM1*0/GSTA1*A genotype exhibited significantly shorter time to death of stroke or MI in comparison with carriers of either GSTM1-active or at least one GSTA1*B gene variant. The best survival rate regarding cardiovascular outcome was found for ESRD patients with combined GSTM1-active and mutant GSTA1*B/*B genotype. Conclusions: Combined GSTM1*0/GSTA1*A genotypes might be considered as genetic markers for cardiovascular death risk in ESRD patients, which may permit targeting of preventive and early intervention. © 2014 Suvakov et al.; licensee BioMed Central Ltd.

BackgroundIncreased oxidative stress is a hallmark of end-stage renal disease (ESRD). Glutathione S-transferases (GST) are involved in the detoxification of xenobiotics and protection of oxidative damage. We hypothesized that genetic polymorphism in antioxidant enzymes GSTA1, GSTM1, GSTP1 and GSTT1 is more frequent in ESRD and modulates the degree of oxidative stress in these patients.MethodsGSTA1, GSTM1, GSTP1 and GSTT1 genotypes were determined in 199 ESRD patients and 199 age-and gender-matched controls. Markers of protein and lipid oxidative damage [thiol groups, carbonyl groups, advanced oxidative protein products, nitrotyrosine, malondialdehyde (MDA) and MDA adducts], together with total oxidant status and pro-oxidant-antioxidant balance were determined. Results Individual GST polymorphisms influence vulnerability to both protein and lipid oxidation, with GSTM1-null gene variant having the most pronounced effect. Furthermore, a strong combined effect of null/low-activity GSTM1, GSTT1, GSTA1 and GSTP1 genotypes in terms of susceptibility towards oxidative and carbonyl stress was found in ESRD patients. When patients were stratified according to GSTM1 and GSTT1, the highest oxidant damage was noted in those with the GSTM1-null/GSTT1-null genotype. The observed effect was even stronger in patients with the third low-activity GSTP1 or GSTA1 genotype. Finally, the level of oxidative and carbonyl stress was most pronounced in the subgroup of patients with all four null or low-activity GSTM1, GSTT1, GSTP1 and GSTA1 genotypes.ConclusionsAccording to the GST genotype, ESRD patients may be stratified in terms of the level of oxidative and carbonyl stress that might influence cardiovascular prognosis, but could also improve efforts towards individualization of antioxidant treatment. © 2013 The Author.

Background/Aims: Glucocorticoids and classic immunosuppressive drugs can improve disease activity in primary glomerulonephritis (GN). However, these drugs have serious toxicity and patients frequently experience inadequate response or relapse, so there is a need for alternative agents. This multicenter uncontrolled study analyzed the efficacy and safety of mycophenolate mofetil (MMF) in high-risk patients with primary GN. Methods: A total of 51 patients with biopsy-proven membranous (n = 12), membranoproliferative (n = 15), mesangioproliferative (n = 10), focal segmental glomerulosclerosis (n = 13) and minimal change disease (n = 1) received MMF with low-dose corticosteroids for 1 year. The primary outcome included the number of patients with complete/partial remission. Results: Proteinuria significantly decreased, from its median value of 4.9 g/day (IQR 2.9-8.4) to 1.28 g/day (IQR 0.5-2.9), p < 0.001. The urine protein/creatinine ratio significantly improved, from a median of 3.72 (IQR 2.13-6.48) to 0.84 (IQR 0.42-2.01), p < 0.001. The mean area under the curve for proteinuria significantly decreased, from 4.99 ± 3.46 to 2.16 ± 2.46, between the first (visits 1-2) and last (vists 4-5) treatment periods (p < 0.001). The change was similar for every type of GN, without difference between groups. eGFR slightly increased (62.1 ± 31.8 to 65.3 ± 31.8 ml/min, p = n.s.) and ESR, total proteins, albumins, total- and HDL-cholesterol parameters improved significantly. Systolic, diastolic and mean blood pressure decreased (p < 0.02 for systolic blood pressure). The age of patients was the only independent predictor of complete or partial remission. Conclusion: MMF proved to be efficient in 70% of high-risk patients with primary GN, who reached either complete or partial remission without safety concern after 12 months of treatment. Favorable effects of MMF therapy have to be confirmed in the long term and particularly after discontinuation of the drug. © 2009 S. Karger AG, Basel.