Total,free, and protein-bound thiols in plasma of peritoneal dialysis and predialysis patients

Thiol compounds such as glutathione, homocysteine, and cysteinyl-glycine are the natural reservoir of reductive capacity of the cells. Chronic renal failure is accompanied by disturbances in redox status of plasma thiols. The aim of the present study was to compare the changes in concentrations of different forms of thiols in plasma of terminal renal failure patients, nondialyzed and on peritoneal dialysis. Total concentrations of different redox forms of thiols were determined by high performance liquid chromatography. We observed that total concentration of glutathione in terminal renal failure patients decreased and total concentration of the remaining thiols in these patients significantly increased. Continuous ambulatory peritoneal dialysis had the following features in comparison with nondialyzed patients: (1) glutathione and cysteine concentration was restored and (2) free fraction of thiols rose, while protein-bound fraction dropped (except for homocysteine). Continuous ambulatory peritoneal dialysis corrects total concentration of glutathione and cysteine, in comparison with nondialyzed patients.     

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.

     

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.