title: Stimulation of neovascularization by the anti-angiogenic factor PEDF.
abstract: OBJECTIVE
  Examine the effect of (pigment epithelium-derived growth factor; PEDF) on laser-induced choroidal neovascularization (CNV).
  
  
  METHODS
  Adult C57Bl/6 mice were anesthetized and four laser spots were placed in each quadrant of the fundus with a krypton red laser (614 nm, 50 microm, 0.05 second, 200 mW). Animals were treated with various doses of PEDF administered with miniosmotic pumps implanted subcutaneously. Seven days after laser treatment, mice were perfused with 3% FITC high-molecular-weight dextran, the eyes enucleated, and neovascularization analyzed by confocal microscopy. Data were recorded as the volume of the neovascular complex. The effect of PEDF on endothelial cell migration, vascular tube formation in synthetic basement membrane, and VEGF production was also determined.
  
  
  RESULTS
  Mice receiving a lower dose of PEDF (90 microg/mL) had significantly decreased areas of CNV. A high dose of PEDF (360 microg/mL) significantly increased CNV, whereas an intermediate dose (180 microg/mL) of PEDF had no effect. PEDF inhibited endothelial cell migration and vascular tube formation at lower doses (0.5-5 microg/mL). High doses of PEDF (25-50 microg/mL) stimulated endothelial cell migration, enhanced vascular tube formation in vitro, and stimulated VEGF production from endothelial cells. Neutralizing anti-VEGF antibody completely reversed the stimulatory effects of high doses of PEDF on CNV in vivo.
  
  
  CONCLUSIONS
  PEDF demonstrates opposing effects on CNV and endothelial cell function. Whereas low doses are inhibitory, high doses can augment the development of the neovasculature. These results suggest that the effects of PEDF on neovascularization are more complex than originally believed and that caution should be exercised when PEDF therapies are considered.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid, St. Louis, MO 63110, USA.
authors.forename: Rajendra S
authors.initials: RS
authors.lastname: Apte
authors.forename: Ramon A
authors.initials: RA
authors.lastname: Barreiro
authors.forename: Elia
authors.initials: E
authors.lastname: Duh
authors.forename: Olga
authors.initials: O
authors.lastname: Volpert
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Ferguson
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D020256:Choroidal Neovascularization / Q000139:chemically induced* / Q000209:etiology; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D005136:Eye Proteins / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D007834:Lasers; D051379:Mice; D008810:Mice, Inbred C57BL; D009414:Nerve Growth Factors / Q000008:administration & dosage / Q000494:pharmacology; D015843:Serpins / Q000008:administration & dosage / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000276:immunology; D000099174:Pigment Epithelium-Derived Factor
chemical_list: D000906:Antibodies; D005136:Eye Proteins; D009414:Nerve Growth Factors; D015843:Serpins; D042461:Vascular Endothelial Growth Factor A; D000099174:Pigment Epithelium-Derived Factor