title: Pharmacological inhibition of integrin alphavbeta3 aggravates experimental liver fibrosis and suppresses hepatic angiogenesis.
abstract: The vitronectin receptor integrin alphavbeta3 promotes angiogenesis by mediating migration and proliferation of endothelial cells, but also drives fibrogenic activation of hepatic stellate cells (HSCs) in vitro. Expecting antifibrotic synergism, we studied the effect of alphavbeta3 inhibition in two in vivo models of liver fibrogenesis. Liver fibrosis was induced in rats by way of bile duct ligation (BDL) for 6 weeks or thioacetamide (TAA) injections for 12 weeks. A specific alphavbeta3 (alphavbeta5) inhibitor (Cilengitide) was given intraperitoneally twice daily at 15 mg/kg during BDL or after TAA administration. Liver collagen was determined as hydroxyproline, and gene expression was quantified by way of quantitative polymerase chain reaction. Liver angiogenesis, macrophage infiltration, and hypoxia were assessed by way of CD31, CD68 and hypoxia-inducible factor-1alpha immunostaining. Cilengitide decreased overall vessel formation. This was significant in portal areas of BDL and septal areas of TAA fibrotic rats and was associated with a significant increase of liver collagen by 31% (BDL) and 27% (TAA), and up-regulation of profibrogenic genes and matrix metalloproteinase-13. Treatment increased gamma glutamyl transpeptidase in both models, while other serum markers remained unchanged. alphavbeta3 inhibition resulted in mild liver hypoxia, as evidenced by up-regulation of hypoxia-inducible genes. Liver infiltration by macrophages/Kupffer cells was not affected, although increases in tumor necrosis factor alpha, interleukin-18, and cyclooxygenase-2 messenger RNA indicated modest macrophage activation.
  
  
  CONCLUSIONS
  Specific inhibition of integrin alphavbeta3 (alphavbeta5) in vivo decreased angiogenesis but worsened biliary (BDL) and septal (TAA) fibrosis, despite its antifibrogenic effect on HSCs in vitro. Angiogenesis inhibitors should be used with caution in patients with hepatic fibrosis.
authors.affiliation: Department of Medicine I, University of Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Patsenker
authors.forename: Yury
authors.initials: Y
authors.lastname: Popov
authors.forename: Felix
authors.initials: F
authors.lastname: Stickel
authors.forename: Vreni
authors.initials: V
authors.lastname: Schneider
authors.forename: Monika
authors.initials: M
authors.lastname: Ledermann
authors.forename: Hans
authors.initials: H
authors.lastname: Sägesser
authors.forename: Gerald
authors.initials: G
authors.lastname: Niedobitek
authors.forename: Simon L
authors.initials: SL
authors.lastname: Goodman
authors.forename: Detlef
authors.initials: D
authors.lastname: Schuppan
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000166:cytology; D055166:Hepatic Stellate Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D039302:Integrin alphaVbeta3 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008026:Ligation / Q000009:adverse effects; D008099:Liver / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology; D008103:Liver Cirrhosis / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012910:Snake Venoms / Q000494:pharmacology*; D013853:Thioacetamide / Q000009:adverse effects; D005723:gamma-Glutamyltransferase / Q000378:metabolism; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D039302:Integrin alphaVbeta3; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D012910:Snake Venoms; D013853:Thioacetamide; D005723:gamma-Glutamyltransferase; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C497444:Hif1a protein, rat; C422910:Cilengitide