α-Lipoic acid increases the viability of nephrocytes and elevates sulfane sulfur level in plasma of patients with chronic kidney disease.

BACKGROUND: Kidney diseases are a major global health problem affecting millions of people. Despite this, there is as yet no effective drug therapy improving outcome in patients with renal disease. The aim of this study was to examine the nephroprotective effect of α-lipoic acid (ALA) in vitro and to examine the effect of ALA administered in vivo on the production of reactive sulfur species (RSS), including hydrogen sulfide (H2S) and compounds containing sulfane sulfur. METHODS: The effect of ALA was studied in vitro by determining the viability of human embryonic kidney cells (HEK293) in normoxic and hypoxic conditions as well as in vivo in two groups of chronic kidney disease (CKD) patients: non-dialyzed (ND) and undergoing continuous ambulatory peritoneal dialysis (PD) after 30 days of ALA supplementation. RESULTS: The results revealed that the viability of HEK293 cells was significantly decreased by hypoxic conditions, while ALA administered during hypoxia increased the viability to the level observed in normoxic conditions. Studies performed in plasma of CKD patients after ALA supplementation suggested that ALA did not affect the parameters of oxidative stress, while significantly increased the level of reactive sulfane sulfur in both ND and PD patients suffering from CKD. The results suggest that ALA can exert nephroprotective effects which are related to sulfane sulfur production.

Current epidemiology and practice patterns in prevention and treatment of PD-related infections in Poland.

BACKGROUND: Peritoneal dialysis (PD) related infections are associated with technique failure and mortality. The aim of this multicentre study was to examine epidemiology, treatment and outcomes of PD-related infections in Poland as well as practice patterns for prevention of these complications in the context of current ISPD recommendations. METHODS: A survey on PD practices in relation to infectious complications was conducted in 11 large Polish PD centres. Epidemiology of peritonitis and exit-site infections (ESI) was examined in all patients treated in these units over a 2 year period. RESULTS: The study included data on 559 PD patients with 62.4% on CAPD. Practice patterns for prevention of infectious complications are presented. The rate of peritonitis was 0.29 episodes per year at risk, with Gram positive microorganisms responsible for more than 50% of infections and 85.8% effectively treated. Diagnosis and treatment followed ISPD guidelines however most units did not provide an anti-fungal prophylaxis. Although neither of the centres reported routine topical mupirocin on catheter exit-site, the rate of ESI was low (0.1 episodes per year at risk), with Staphylococcus aureus as most common pathogen and full recovery in 78.3% of cases. CONCLUSION: The study shows rewarding outcomes in prevention and treatment of PD-associated infections, mainly due to a thorough compliance with the current ISPD guidelines, although some deviations from the recommendations in terms of practice patterns have been observed. More studies are needed in large numbers of patients to differentiate the importance of specific recommendations and further support the guidelines.

The effect of lipoate on anaerobic cysteine metabolism in erythrocytes of patients treated with peritoneal dialysis.

BACKGROUND: The studies aimed to evaluate the changes in cysteine sulfur metabolism in erythrocytes of end-stage renal failure (ESRF) patients treated with continuous ambulatory peritoneal dialysis (CAPD) caused by a one-month lipoate (LA) supplementation at a daily dose of 600 mg. METHODS: The level of sulfane sulfur and activity of sulfurtransferases were determined in erythrocytes of CAPD patients and in the control group. RESULTS: The sulfane sulfur level in erythrocytes of CAPD patients did not differ compared with healthy volunteers but LA supplementation increased the reactive sulfur concentration. LA elevated also cystathionase activity. CONCLUSIONS: LA supplementation in ESRF patients treated with CAPD increases the sulfane sulfur level which indicates the augmentation of its antioxidant and regulatory properties.

Thiol levels, protein carbonylation and anaerobic sulfur metabolism in erythrocytes of peritoneal dialysis and predialysis patients.

AIM: The goal of the present study was to investigate the changes in sulfur metabolism in erythrocytes of end-stage renal failure patients. METHODS: The following substances were determined in erythrocytes of chronic kidney disease patients before dialysis, patients treated with continuous ambulatory peritoneal dialysis, and in a group of healthy volunteers: (i) sulfane sulfur level and activity of the enzymes involved in its metabolism and in cyanide detoxification; (ii) concentration of total and non-protein sulfhydryl groups -SH; and (iii) protein carbonylation rate. RESULTS: Erythrocytes of chronic kidney disease patients in predialysis period contained lower levels of sulfane sulfur, non-protein thiols, total thiols and 3-mercaptopyruvate sulfotransferase. On the other hand, in erythrocytes of end-stage renal failure patients treated with continuous ambulatory peritoneal dialysis, sulfane sulfur, non-protein thiols, total thiols and 3-mercaptopyruvate sulfotransferase activity remained at the level observed in healthy controls. These changes indicate a disturbed thiol balance and anaerobic cysteine metabolism in non-dialysis patients, whereas continuous ambulatory peritoneal dialysis patients did not show these disorders. γ-Cystathionase activity was equally elevated in predialysis period and in peritoneal dialysis patients, which means that chronic kidney disease pathology is accompanied by an increased expression of this enzymatic activity in erythrocytes. Erythrocytic rhodanese activity was unchanged and stayed at the control level in both groups. Protein carbonylation rate was equally enhanced in both patient groups, which indicated acceleration of oxidative processes and inability of continuous ambulatory peritoneal dialysis to correct these changes in erythrocytes. CONCLUSION: The CAPD as a replacement therapy helps to preserve thiol levels and anaerobic sulfur metabolism in erythrocytes.