cysteinylglycine and Nephrotic-Syndrome

The role of idiopathic nephrotic syndrome (INS) in the pathogenesis of atherosclerosis in childhood has not been clearly elucidated. However, antioxidative defense in INS is thought to be imbalanced. This study aimed to assess the changes of plasma concentration of selected aminothiols in the blood of children with INS at various stages of the disease.. This cross-sectional study was conducted in 125 children aged 2-18 years. The children were divided into 4 groups: group A, early relapse (n=37); group B, early remission for 4-6 weeks from the onset (n=37); group C, late steroid-free remission (n=31); and group D, long-term remission for 2-5 years (n=20). Control group (E) consisted of 30 age- and gender-matched healthy children. The study protocol comprised an analysis of plasma concentrations of glutathione, homocysteine, cysteine and cysteinylglycine by high-performance liquid chromatography. Fractions of protein-bound and free aminothiols were measured. Endothelial injury was assessed by thrombomodulin, PAI-1 concentration, and von Willebrand factor activity.. The children with INS had unbalanced aminothiol metabolism only in relapse and early remission, that shifted towards increased oxidative processes. Administration of cyclosporine A caused a significant increase in homocysteine and cysteine concentration. Changes in aminothiol metabolism were significantly related to endothelial injury.. The findings of this study may be helpful in elucidating the pathogenesis of premature atherosclerosis in patients with INS refractory to the treatment or in the case of frequent relapse.

Topics: Adolescent; Biomarkers; Biopsy, Needle; Child; Child, Preschool; Chromatography, High Pressure Liquid; Cohort Studies; Cross-Sectional Studies; Cyclosporine; Dipeptides; Disease Progression; Female; Follow-Up Studies; Glutathione; Homocysteine; Humans; Immunohistochemistry; Male; Nephrotic Syndrome; Recurrence; Risk Assessment; Sensitivity and Specificity; Severity of Illness Index; Sulfhydryl Compounds; Treatment Outcome

The levels of different fractions of homocysteine, cysteine and cysteinylglycine were investigated in 17 patients on chronic hemodialysis, 9 patients with reduced renal function and 4 patients with nephrotic syndrome and compared with 14 healthy subjects. Total plasma homocysteine, cysteine and cysteinylglycine were increased in the patients with reduced renal function and in those on chronic hemodialysis. The free (non-protein-bound) forms of plasma homocysteine and cysteine were significantly increased in all groups of patients. The reduced forms of plasma homocysteine and cysteine were, however, not increased in any of the patient groups; on the contrary, reduced plasma homocysteine was significantly decreased in the group of patients with reduced renal function. These findings indicate that the plasma levels of reduced forms of the thiol compounds are relatively normal and do not merely mirror the elevation of the disulfide forms. The possible relation between homocysteine and increased atherogenesis in patients with renal failure is discussed.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Cysteine; Dipeptides; Female; Homocysteine; Humans; Kidney Failure, Chronic; Male; Middle Aged; Nephrotic Syndrome; Renal Dialysis; Sulfhydryl Compounds