title: Inhibition of cellular transdifferentiation by losartan minimizes but does not reverse type 2 diabetes-induced renal fibrosis.
abstract: OBJECTIVE
  Transformer Growth Factor (TGF-β1) and angiotensin II (AngII) induce epithelial mesenchymal transition (EMT) and myofibroblastic transdifferentiation (MFT) contributing to renal fibrosis. The present study evaluated the capacity of an AT1 receptor blocker (losartan) to induce the regression of pre-existing fibrosis via interference with MFT and EMT in a rat model of type 2 diabetes, and in cultured mesangial cells (MCs) stimulated with high glucose and AngII.
  
  
  METHODS
  After 12 weeks of diabetes induction (D12 group), animals showing evidence of nephropathy, were divided in groups untreated for additional 8 weeks (D20 group) and treated for additional 8 weeks with losartan (D20+los group).
  
  
  RESULTS
  D12 animals presented hyperglycemia, insulin resistance, hypertension, proteinuria, increased levels of TGF-β1 and MFT/EMT markers. Losartan stabilized all of these parameters and hindered the progression of fibrosis, but it did not reverse the pre-existing fibrotic manifestations. Losartan reduced TGF-β1 in the tubules, but not in the glomeruli. Stimulated MC exhibited myofibroblast phenotype and capacity for migration, which were completely reversed by losartan.
  
  
  CONCLUSIONS
  Cellular transition may play a role in diabetes-inducing renal fibrogenesis in both AngII-TGF-β1 axis-dependent and independent manners. Losartan was efficient in preventing cells from undergoing further transdifferentiation, but this strategy was not sufficient to induce regression of the pre-existing tissue fibrosis.
authors.affiliation: Department of Medicine, Federal University of São Paulo, Brazil.
authors.forename: Carine P
authors.initials: CP
authors.lastname: Arnoni
authors.affiliation: Department of Medicine, Federal University of São Paulo, Brazil.
authors.forename: Edgar
authors.initials: E
authors.lastname: Maquigussa
authors.affiliation: Department of Medicine, Federal University of São Paulo, Brazil.
authors.forename: Clévia S
authors.initials: CS
authors.lastname: Passos
authors.affiliation: Department of Medicine, Federal University of São Paulo, Brazil.
authors.forename: Luciana G
authors.initials: LG
authors.lastname: Pereira
authors.affiliation: Department of Medicine, Federal University of São Paulo, Brazil mirian@nefro.epm.br.
authors.forename: Mirian A
authors.initials: MA
authors.lastname: Boim
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D054338:Cell Transdifferentiation / Q000187:drug effects*; D002784:Cholesterol / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications / Q000188:drug therapy* / Q000473:pathology*; D004305:Dose-Response Relationship, Drug; D005355:Fibrosis; D007674:Kidney Diseases / Q000097:blood / Q000150:complications* / Q000188:drug therapy* / Q000473:pathology; D019808:Losartan / Q000494:pharmacology* / Q000627:therapeutic use*; D008297:Male; D011507:Proteinuria / Q000150:complications; D017208:Rats, Wistar
chemical_list: D001786:Blood Glucose; D002784:Cholesterol; D019808:Losartan
keywords: Angiotensin II; epithelial mesenchymal transition; mesangial cell; myofibroblastic transdifferentiation; renal fibrosis; type 2 diabetes