Steva Pljesa

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

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

Altered antioxidant capacity in human renal cell carcinoma: role of glutathione associated enzymes.

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 alpha and pi 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, gamma-glutamylcysteine synthetase (gamma-GCS), gamma-glutamyl transferase (gamma-GT), and glutathione reductase (GR), as well as the activities of antioxidant enzymes glutathione peroxidase (GPX) and catalase (CAT) were determined spectrophotometrically. GST alpha and pi 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, gamma-GCS, is up-regulated (P < 0.001), while the activities of gamma-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 alpha (P < 0.001) and unchanged GST pi expression at the protein level. CONCLUSIONS Changes in redox status in RCC as a consequence of decreased enzyme antioxidant capacity, together with altered GST alpha expression, may be important factors in development and tumor growth. The up-regulation of gamma-GCS and high levels of GSH in RCC may be an attempt to limit injury caused by oxidative stress.

Mycophenolate Mofetil in High-Risk Patients with Primary Glomerulonephritis: Results of a 1-Year Prospective Study

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.

Treatment of Lupus Nephritis by Mycophenolate Mofetil

Background/Aims: Mycophenolate mofetil (MMF) has been increasingly used for the treatment of lupus nephritis (LN). The aim of this study was to examine the efficacy and safety of MMF used with low doses of corticosteroids as maintenance therapy in patients with LN. Methods: The study covered 35 patients, most of them with proliferative types of LN (5 WHO class III, 26 class IV), while 1 had class V and 3 class VI nephritis. MMF was administered in the dose of 1.5–2 g/24 h and prednisone at 10–20 mg/day. The treatment effects were followed over a 12-month period. Results: After 3 months of therapy significant reduction in proteinuria was achieved (2.1 ± 2.4 g/24 h vs. 1.0 ± 1.0 g/24 h, p < 0.01) and maintained to the end of the study. In parallel, a significant rise in serum albumin, a fall of cholesterol and a significant increase in mean glomerular filtration rate were noted. Complete remission was achieved in 16 patients (45.7%), including all patients in class III and V plus 10 patients in class IV. Not a single adverse effect was observed. Conclusion: MMF combined with low doses of steroids is an effective and safe treatment for the maintenance of stable remission of LN.

[Predictors of mortality in dialysis patients--association between malnutrition, inflammation and atherosclerosis (MIA syndrome)].

INTRODUCTION Numerous recent studies have shown increased comorbidity and mortality in dialysis patients with malnutrition. Protein-energy malnutrition with muscle wasting occurs in a large proportion of patients with chronic renal failure and is, in addition to atherosclerosis, a strong risk factor for mortality in patients undergoing dialysis. Malnutrition is also associated with increased cardiovascular mortality in dialysis patients. PATHOGENIC FACTORS OF MALNUTRITION IN DIALYSIS PATIENTS Malnutrition is associated with a number of metabolic and vascular abnormalities. These factors include hypoalbuminemia, dyslipidemia with raised triglyceride concentrations, low-density lipoprotein and very low-density lipoprotein concentrations, insulin resistance and high concentrations of acute-phase proteins. Low serum albumin concentration, usually used as an index of malnutrition, is highly associated with increased mortality risk in dialysis patients. However, serum albumin is affected by factors other than malnutrition and high concentrations of acute-phase proteins, such as C-reactive protein (CRP), which correlate with low serum albumin in malnourished patients on dialysis. Oxidative stress has emerged as an important cofactor for development of endothelial dysfunction as premature atherosclerosis. In this context, malnutrition, inflammation and markers of oxidative stress are associated with vascular diseases. ETIOLOGY OF MALNUTRITION IN DIALYSIS PATIENTS In recent studies several reports have suggested that inflammation, alone or in combination with low protein intake, plays a significant role in etiology of malnutrition in uremic patients. Lipid abnormalities may not only be a consequence of renal disease, but also contribute to its progression. Lipoprotein (a) is also associated with various atherosclerotic diseases. THERAPY OPTIONS New treatment strategies, such as high protein/energy vs. standard protein/energy nutritional regimens, are necessary as well as food intake and dietary supplements. Intensive supplementation of (1.5 g protein/kg/d and 45 kcal/kg/d) is necessary to improve nutritional status of dialysis patients. CONCLUSION Cellular basis of pathogenetic factors in malnutrition is unclear. It is, however, now recognized that oxidative stress and inflammatory cytokine aggravates the nutritional status of these patients.

Associations of GSTM1*0 and GSTA1*A genotypes with the risk of cardiovascular death among hemodialyses patients.

BackgroundThe 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.MethodsTotal 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.ResultsGSTM1-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.ConclusionsCombined 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.

Compliance with guidelines and predictors of mortality in hemodialysis. Learning from Serbia patients

OBJECTIVES The aims of the study were to determine the percentage of patients on regular hemodialysis (HD) in Serbia failing to meet KDOQI guidelines targets and find out factors associated with the risk of time to death and the association between guidelines adherence and patient outcome. METHODS A cohort of 2153 patients on regular HD in 24 centers (55.7% of overall HD population) in Serbia were followed from January 2010 to December 2012. The percentage of patients failing to meet KDOQI guidelines targets of dialysis dose (Kt/V>1.2), hemoglobin (>110g/L), serum phosphorus (1.1-1.8mmol/L), calcium (2.1-2.4mmol/L) and iPTH (150-300pg/mL) was determined. Cox proportional hazards analysis was used to select variables significantly associated with the risk of time to death. RESULTS The patients were on regular HD for 5.3±5.3 years, dialyzed 11.8±1.9h/week. Kt/V<1.2 had 42.4% of patients, hemoglobin <110g/L had 66.1%, s-phosphorus <1.1mmol/L had 21.7% and >1.8mmol/L 28.6%, s-calcium <2.1mmol/L had 11.7% and >2.4mmol/L 25.3%, iPTH <150pg/mL had 40% and >300pg/mL 39.7% of patients. Using Cox model (adjustment for patient age, gender, duration of HD treatment) age, duration of HD treatment, hemoglobin, iPTH and diabetic nephropathy were selected as significant independent predictors of time to death. When targets of five examined parameters were included in Cox model, target for KtV, hemoglobin and iPTH were found to be significant independent predictors of time to death. CONCLUSION Substantial proportion of patients examined failed to meet KDOQI guidelines targets. The relative risk of time to death was associated with being outside the targets for Kt/V, hemoglobin and iPTH.