title: Increased choroidal neovascularization following laser induction in mice lacking lysyl oxidase-like 1.
abstract: OBJECTIVE
  Age-related degradation of the elastic lamina in Bruch's membrane may have a permissive effect on the growth of choroidal neovascularization (CNV). This study investigated the influence of defective elastic fiber maintenance in the development of laser-induced CNV.
  
  
  METHODS
  A mouse lacking lysyl oxidase-like (LOXL)-1, an enzyme essential for elastin polymerization, was studied. The morphologic characteristics of the elastic lamina within Bruch's membrane were examined in mutant and wild-type (WT) eyes. Laser-induced CNV was evaluated by fluorescein angiography and choroidal flat mounts. Immunohistochemistry for elastin was performed on the CNV lesions, and vascular endothelial growth factor (VEGF) levels were determined by ELISA. Soluble elastin and matrix metalloproteinase (MMPs) levels were also analyzed by immunoblotting.
  
  
  RESULTS
  The elastic lamina of Bruch's membrane in the LOXL1-deficient mice was fragmented and less continuous than in the WT controls. The mutant mice showed increased levels of soluble elastin peptides and reduced elastin polymer deposition in neovascular membranes. Significantly larger CNV with greater leakage on fluorescein angiography developed in mutant mice. VEGF levels in the RPE/choroid were higher in the knockout mice on days 7 and 14 after laser (P < 0.05). MT1-MMP (MMP14) was also elevated after laser in the LOXL1 mutant eyes compared to the WT controls.
  
  
  CONCLUSIONS
  These results show that a systemic defect in elastic fiber deposition affects Bruch's membrane integrity and leads to more aggressive CNV growth. The latter may be partially mediated by abnormal signaling from the accumulation of soluble elastin peptides.
authors.affiliation: Angiogenesis Laboratory and Laser Laboratory, Retina Research Institute, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts 02114, USA.
authors.forename: Hyeong Gon
authors.initials: HG
authors.lastname: Yu
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Liu
authors.forename: Szilard
authors.initials: S
authors.lastname: Kiss
authors.forename: Edward
authors.initials: E
authors.lastname: Connolly
authors.forename: Evangelos S
authors.initials: ES
authors.lastname: Gragoudas
authors.forename: Norman A
authors.initials: NA
authors.lastname: Michaud
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Bulgakov
authors.forename: Michael
authors.initials: M
authors.lastname: Adamian
authors.forename: Margaret M
authors.initials: MM
authors.lastname: DeAngelis
authors.forename: Joan W
authors.initials: JW
authors.lastname: Miller
authors.forename: Tiansen
authors.initials: T
authors.lastname: Li
authors.forename: Ivana K
authors.initials: IK
authors.lastname: Kim
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000502:physiology*; D000818:Animals; D016570:Bruch Membrane / Q000201:enzymology* / Q000648:ultrastructure; D020256:Choroidal Neovascularization / Q000201:enzymology* / Q000209:etiology / Q000503:physiopathology*; D004547:Elastic Tissue / Q000201:enzymology* / Q000648:ultrastructure; D004549:Elastin / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005451:Fluorescein Angiography; D019084:Fluorescent Antibody Technique, Indirect; D015151:Immunoblotting; D017075:Laser Coagulation; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016253:Microscopy, Immunoelectron; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D004549:Elastin; D000594:Amino Acid Oxidoreductases; C482019:Loxl1 protein, mouse; D020782:Matrix Metalloproteinases