title: Erythropoietin prevents dialysis fluid-induced apoptosis of mesothelial cells.
abstract: BACKGROUND
  In peritoneal dialysis (PD)-treated patients, denudation of the mesothelium correlates with peritoneal fibrosis and vascular changes. Since recombinant human erythropoietin (rHuEPO) induces a range of cytoprotective cellular responses, rHuEPO treatment may reduce PD fluid (PDF)-induced damage.
  
  
  METHODS
  To investigate the antiapoptotic effect and mechanism of rHuEPO in peritoneal mesothelial cells (PMCs), isolated mice PMCs were used for in vitro characterization of rHuEPO effects. To confirm the in vitro effects, active caspase-3 was analyzed in imprints of liver visceral peritoneum of mice pretreated overnight with rHuEPO (5000 U/kg intraperitoneally) and exposed to PDF (Dianeal 4.25%; Baxter Healthcare, Deerfield, Illinois, USA) for 4 hours.
  
  
  RESULTS
  Mouse PMCs expressed EPO-receptor mRNA and protein. Short exposure to rHuEPO (5 U/mL) induced phosphorylation of JAK2, STAT5, and ERK1/2. PMCs pretreated for 1 hour with rHuEPO showed reduced PDF-induced caspase-3 activation (49.6%) and DNA fragmentation (38.4%) in comparison to cells treated by PDF alone (p < 0.05). rHuEPO treatment induced an increase in ERK1/2 phosphorylation and reduced levels of PDF-induced phospho-P38. PD98059, a specific inhibitor of ERK activation, fully blocked the protective effect of rHuEPO. In mice, rHuEPO reduced the apoptotic effect of PDF, as assessed by the level of active caspase-3.
  
  
  CONCLUSIONS
  Our study presents new insights into clinical use of rHuEPO in the setting of PD. We found that rHuEPO provides ERK1/2-dependent protection to PMCs from PDF-induced apoptosis. The use of rHuEPO, or any of its new derivatives that do not stimulate erythropoiesis, should be considered for peritoneal preservation.
authors.affiliation: Department of Nephrology, Soroka Medical University Center, Beer-Sheva, Israel.
authors.forename: Marina
authors.initials: M
authors.lastname: Vorobiov
authors.forename: Myriam
authors.initials: M
authors.lastname: Malki
authors.forename: Alla
authors.initials: A
authors.lastname: Shnaider
authors.forename: Ana
authors.initials: A
authors.lastname: Basok
authors.forename: Boris
authors.initials: B
authors.lastname: Rogachev
authors.forename: Eli C
authors.initials: EC
authors.lastname: Lewis
authors.forename: Cidio
authors.initials: C
authors.lastname: Chaimovitz
authors.forename: Moshe
authors.initials: M
authors.lastname: Zlotnik
authors.forename: Amos
authors.initials: A
authors.lastname: Douvdevani
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3 / Q000032:analysis; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects / Q000502:physiology*; D004920:Erythropoiesis / Q000187:drug effects; D004921:Erythropoietin / Q000494:pharmacology*; D047468:Immunoprecipitation; D066298:In Vitro Techniques; D053614:Janus Kinase 2 / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010537:Peritoneum / Q000737:chemistry; D010766:Phosphorylation; D017467:Receptors, Erythropoietin / Q000378:metabolism; D011994:Recombinant Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050799:STAT5 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D017467:Receptors, Erythropoietin; D011994:Recombinant Proteins; D050799:STAT5 Transcription Factor; C103998:epoetin beta; D004921:Erythropoietin; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2; D048052:Mitogen-Activated Protein Kinase 3; C505409:Casp3 protein, mouse; D053148:Caspase 3