title: Recombinant human erythropoietin pretreatment alleviates renal glomerular injury induced by cardiopulmonary bypass by reducing transient receptor potential channel 6-nuclear factor of activated T-cells pathway activation.
abstract: OBJECTIVE
  Acute renal injury after cardiopulmonary bypass is common and associated with high mortality. We aimed to demonstrate the glomerular protective effects of recombinant human erythropoietin using an in vivo rat cardiopulmonary bypass model and to explore the possible mechanism.
  
  
  METHODS
  Dose-related renal protective effects of recombinant human erythropoietin were studied in phase I. Male Sprague Dawley rats were randomly divided into 5 groups: sham group, cardiopulmonary bypass group, and 3 recombinant human erythropoietin-treated cardiopulmonary bypass groups (bolus doses of 500, 3000, and 5000 U/kg 24 hours before surgery). Blood and urine samples were collected just before surgery and at 2, 4, 24, 48, and 72 hours after surgery. In phase II, rats were divided into 3 groups: sham group, cardiopulmonary bypass group, and 5000 U/kg recombinant human erythropoietin group. Kidneys were harvested at 4, 24, 48, and 72 hours after surgery. Ultra-organization of glomeruli was observed. Glomerular transient receptor potential channel 6 (TRPC6) expression was studied by immunofluorescence and Western blot. Nuclei nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1) activity was analyzed by enzyme-linked immunosorbent assays and electrophoretic mobility shift assay.
  
  
  RESULTS
  Pretreatment of 5000 U/kg recombinant human erythropoietin decreased the urine protein (72 hours: 7.82 ± 1.13 g/L vs 11.28 ± 1.73 g/L), serum creatinine (72 hours: 35.0 ± 3.5 μmol/L vs 60.7 ± 7.6 μmol/L), and cystatin-C (2 hours: 336.5 ± 28.2 μg/L vs 452.6 ± 63.8 μg/L) compared with the control group (P < .01). Cardiopulmonary bypass induced morphologic abnormalities of podocyte foot processes and slit diaphragms, which was improved by recombinant human erythropoietin. Furthermore, recombinant human erythropoietin significantly relieved glomerular TRPC6 increase and NFATc1 activation induced by cardiopulmonary bypass.
  
  
  CONCLUSIONS
  Pretreatment of 5000 U/kg recombinant human erythropoietin elicited potent glomerular protection against cardiopulmonary bypass. This protection may be partly due to downregulation of glomerular TRPC6-NFATc1 pathway.
authors.affiliation: Department of Anesthesiology, Nanjing Jinling Hospital, Nanjing, China. brightlxm@gmail.com
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Liu
authors.forename: Tingting
authors.initials: T
authors.lastname: Zhang
authors.forename: Weiliang
authors.initials: W
authors.lastname: Xia
authors.forename: Yingwei
authors.initials: Y
authors.lastname: Wang
authors.forename: Ke
authors.initials: K
authors.lastname: Ma
mesh_terms: D058186:Acute Kidney Injury / Q000209:etiology / Q000276:immunology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D000818:Animals; D015415:Biomarkers / Q000097:blood / Q000652:urine; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D003404:Creatinine / Q000097:blood; D055316:Cystatin C / Q000097:blood; D019610:Cytoprotection; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004921:Erythropoietin / Q000494:pharmacology*; D006801:Humans; D007678:Kidney Glomerulus / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D008297:Male; D050778:NFATC Transcription Factors / Q000378:metabolism*; D050199:Podocytes / Q000187:drug effects / Q000378:metabolism; D020011:Protective Agents / Q000494:pharmacology*; D011507:Proteinuria / Q000209:etiology / Q000517:prevention & control; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D050052:TRPC Cation Channels / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D015415:Biomarkers; C525032:Cst3 protein, rat; D055316:Cystatin C; C554270:EPO protein, human; D050778:NFATC Transcription Factors; C584440:NFATC1 protein, rat; D020011:Protective Agents; D011994:Recombinant Proteins; D050052:TRPC Cation Channels; D014157:Transcription Factors; C492145:Trpc6 protein, rat; D004921:Erythropoietin; D003404:Creatinine
keywords: 41.1; 41.3; ARI; CPB; EMSA; IP; NFAT; NFATc1; PBS; RhEPO; TRPC6; acute renal injury; canonical transient receptor potential channel 6; cardiopulmonary bypass; electrophoretic mobility shift assay; intraperitoneally; nuclear factor of activated T cell; nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1; phosphate-buffered saline; recombinant human erythropoietin