title: CRBP-I in the renal tubulointerstitial compartment of healthy rats and rats with renal fibrosis.
abstract: BACKGROUND
  Cellular retinol-binding protein I (CRBP-I), a member of the intracellular lipid-binding protein (iLBP) superfamily, is a specific marker of quiescent stellate cells in the healthy human liver. In the diseased fibrotic/cirrhotic liver, portal and septal myofibroblasts acquire CRBP-I expression, while activated hepatic stellate cells maintain their CRBP-I expression. Here, we investigate the distribution of CRBP-I in the renal cortex of healthy rats and rats with renal fibrosis.
  
  
  METHODS
  Kidneys of healthy and adriamycin-treated rats were studied by immunohistochemistry, using antibodies against CRBP-I, desmin, vimentin and alpha-smooth muscle actin (alpha-SMA). Double stainings were done with immunofluorescence. Western blotting was performed to semi-quantify the expression levels of vimentin, desmin, alpha-SMA and CRBP-I.
  
  
  RESULTS
  In the normal rat kidney, the convoluted proximal tubular epithelial cells express CRBP-I; no expression is found in the interstitium, nor in the glomeruli. In the adriamycin-induced fibrotic rat kidney, CRBP-I expression diminishes in the convoluted proximal tubular epithelial cells, whereas peritubular myofibroblasts in the interstitium acquire CRBP-I expression.
  
  
  CONCLUSIONS
  In the tubulointerstitial compartment of the adriamycin-induced fibrotic rat kidney, CRBP-I is expressed in a different pattern than in the healthy rat kidney. As the convoluted proximal tubular epithelial cells dedifferentiate during fibrosis, CRBP-I expression decreases. Furthermore, de novo expression of CRBP-I is found in activated myofibroblast-like cells in the interstitium of adriamycin-treated rats. CRBP-I is therefore a useful marker to identify a subpopulation of activated/ myodifferentiated fibroblasts in the rat kidney.
authors.affiliation: Vrije Universiteit Brussel, Menselijke Anatomie, Laarbeeklaan 103, B-1090 Brussels, Belgium. Katrien.Van.Beneden@vub.ac.be
authors.forename: Katrien
authors.initials: K
authors.lastname: Van Beneden
authors.forename: Leo A
authors.initials: LA
authors.lastname: van Grunsven
authors.forename: Caroline
authors.initials: C
authors.lastname: Geers
authors.forename: Marina
authors.initials: M
authors.lastname: Pauwels
authors.forename: Alexis
authors.initials: A
authors.lastname: Desmoulière
authors.forename: Dierik
authors.initials: D
authors.lastname: Verbeelen
authors.forename: Albert
authors.initials: A
authors.lastname: Geerts
authors.forename: Christiane
authors.initials: C
authors.lastname: Van den Branden
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D000903:Antibiotics, Antineoplastic; D002454:Cell Differentiation; D003893:Desmin / Q000378:metabolism; D004195:Disease Models, Animal; D015536:Down-Regulation; D004317:Doxorubicin; D005355:Fibrosis; D007687:Kidney Tubules, Proximal / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D009400:Nephrosclerosis / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D054840:Retinol-Binding Proteins, Cellular / Q000378:metabolism*; D015854:Up-Regulation; D014746:Vimentin / Q000378:metabolism
chemical_list: D000199:Actins; D000903:Antibiotics, Antineoplastic; D003893:Desmin; D004317:Doxorubicin; D054840:Retinol-Binding Proteins, Cellular; D014746:Vimentin; C498862:Acta2 protein, rat