title: The vitreous glycoprotein opticin inhibits preretinal neovascularization.
abstract: OBJECTIVE
  Opticin is an extracellular matrix glycoprotein that the authors discovered in the vitreous humor of the eye. It is synthesized by the nonpigmented ciliary epithelium and secreted into the vitreous cavity and, unusually for an extracellular matrix molecule, high-level synthesis is maintained into adult life. Here the authors investigated the hypothesis that opticin influences vascular development in the posterior segment of the eye and pathologic angiogenesis into the normally avascular, mature (secondary) vitreous.
  
  
  METHODS
  Opticin was localized in murine eyes by immunohistochemistry. An opticin knockout mouse was established and vascular development was compared between knockout and wild-type mice. Wild-type and opticin null mice were compared in the oxygen-induced retinopathy model, a model of pathologic angiogenesis, and this model was also used to assess the effects of intravitreal injection of recombinant opticin into eyes of wild-type mice.
  
  
  RESULTS
  Opticin colocalizes with the collagen type II-rich fibrillar network of the vitreous, the inner limiting lamina, the lens capsule, the trabecular meshwork, and the iris. Analyses of the hyaloid and retinal vasculature showed that opticin has no effect on hyaloid vascular regression or developmental retinal vascularization. However, using the oxygen-induced retinopathy model, the authors demonstrated that opticin knockout mice produce significantly more preretinal neovascularization than wild-type mice, and the intravitreal delivery of excess opticin inhibited the formation of neovessels in wild-type mice.
  
  
  CONCLUSIONS
  A lack of opticin does not influence vascular development, but opticin is antiangiogenic and inhibits preretinal neovascularization.
authors.affiliation: School of Biomedicine, University of Manchester, UK.
authors.forename: Magali M
authors.initials: MM
authors.lastname: Le Goff
authors.forename: Hongbin
authors.initials: H
authors.lastname: Lu
authors.forename: Marta
authors.initials: M
authors.lastname: Ugarte
authors.forename: Stephen
authors.initials: S
authors.lastname: Henry
authors.forename: Masamine
authors.initials: M
authors.lastname: Takanosu
authors.forename: Richard
authors.initials: R
authors.lastname: Mayne
authors.forename: Paul N
authors.initials: PN
authors.lastname: Bishop
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D024043:Collagen Type II / Q000378:metabolism; D004195:Disease Models, Animal; D016326:Extracellular Matrix Proteins / Q000008:administration & dosage* / Q000235:genetics; D019084:Fluorescent Antibody Technique, Indirect; D007124:Immunoenzyme Techniques; D058449:Intravitreal Injections; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010100:Oxygen / Q000633:toxicity; D010446:Peptide Fragments; D011509:Proteoglycans / Q000008:administration & dosage* / Q000235:genetics; D011994:Recombinant Proteins / Q000008:administration & dosage; D015861:Retinal Neovascularization / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D014822:Vitreous Body / Q000737:chemistry* / Q000378:metabolism
chemical_list: D024043:Collagen Type II; D016326:Extracellular Matrix Proteins; C498607:Optc protein, mouse; D010446:Peptide Fragments; D011509:Proteoglycans; D011994:Recombinant Proteins; D010100:Oxygen