title: In vitro effect of glutathione precursors on cytotoxicity of amino acids to human mesothelial cells.
abstract: Amino acids (AA) which were proposed as an alternative osmotically active agents in dialysates are toxic to human peritoneal mesothelial cells (HPMC) due to disturbance of the antioxidant-oxidant balance in cells by reducing level of glutathione. We assessed if the addition intracellular glutathione precursors: N-acetyl-cysteine (NAC), tioproline (TP), L--2-oxo--4-thiazolidine acid (PC), and glutathione (GSH) could reduce the cytotoxicity of AA, as measured by inhibition of cells proliferation and disorders of intracellular 86Rb transport. HPMC were obtained from omentum from nonuremic donors and cultured in in vitro conditions. The HPMC proliferation capacity was assessed indirectly by the 3H-methyl-thymidine incorporation assay. The injury to HPMC membrane integrity was assessed by the release of radioisotope molecules of 86Rb from the prelabelled cells. We have found that AA diminished the intracellular potassium (86Rb) influx. Supplementation of AA mixture with NAC enhanced the total 86Rb influx into HMC. Other precursors of intracellular glutathione (TP,PC,GSH) tested in the presence of AA significantly stimulated intracellular transport of 86Rb via Na,K-ATPase dependent channel, but the total intracellular transport of 86Rb was still lower than in control. HMC proliferation was significantly inhibited by AA what was measured by incorporation of H-metyl-tymidine. In the presence of NAC inhibition of HMC proliferation caused by AA was weaker. Our results suggest that some of intracellular glutathione precursors may reduce the disturbances of the HMC function caused by AA.
authors.affiliation: Department of Pathophysiology, Karol Marcinkowski University Medical School in Poznań, Poland. grzyb@mail.usoms.poznan.pl
authors.forename: A E
authors.initials: AE
authors.lastname: Grzybowski
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000596:Amino Acids / Q000633:toxicity*; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000473:pathology; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005978:Glutathione / Q000494:pharmacology*; D006131:Growth Inhibitors / Q000633:toxicity; D006801:Humans; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D010537:Peritoneum / Q000166:cytology*; D011188:Potassium / Q000378:metabolism; D011498:Protein Precursors / Q000494:pharmacology*; D011761:Pyrrolidonecarboxylic Acid; D012414:Rubidium Radioisotopes / Q000378:metabolism; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines
chemical_list: D000596:Amino Acids; D006131:Growth Inhibitors; D011498:Protein Precursors; D012414:Rubidium Radioisotopes; D013844:Thiazoles; D053778:Thiazolidines; C003438:thiazolidine-4-carboxylic acid; D005978:Glutathione; D011188:Potassium; D011761:Pyrrolidonecarboxylic Acid; D000111:Acetylcysteine; C029536:2-oxothiazolidine-4-carboxylic acid