title: Administration of pigment epithelium-derived factor delivered by adeno-associated virus inhibits blood-retinal barrier breakdown in diabetic rats.
abstract: OBJECTIVE
  To evaluate the effect of the recombinant adeno-associated virus (rAAV) vector that expresses human pigment epithelium-derived factor (hPEDF) on reducing blood-retinal barrier (BRB) breakdown in the experimental diabetic rat model.
  
  
  METHODS
  Diabetes was induced by an intraperitoneal (i.p.) injection of streptozotocin (STZ) into 10-week-old male Wister rats. rAAV2-cytomegalovirus (CMV)-hPEDF was delivered into the right eyes by intravitreal injection on the first day after diabetes induction. The contralateral eyes received intravitreal injection of rAAV2-CMV-green fluorescent protein as the paired control. Gene delivery and expression of vascular endothelial growth factor (VEGF), occludin, and intercellular adhesion molecule-1 (ICAM-1) were determined with reverse transciptase PCR or western blotting. BRB breakdown changes were quantified by measuring albumin leakage from retinal blood vessels after an intravenous (i.v.) injection of Evans blue albumin.
  
  
  RESULTS
  Retinal transfection with the hPEDF gene construct led to sustained hPEDF gene expression for 6 months, significantly suppressing VEGF mRNA expression in the retina after 1, 3, and 6 months of diabetes induced by STZ compared with paired controls. Moreover, hPEDF dramatically reduced the levels of retinal ICAM-1 but increased the expression of occludin. Furthermore, BRB breakdown was much lower in hPEDF-injected diabetic animals in comparison with controls after 6 months.
  
  
  CONCLUSIONS
  A single intravitreal injection of rAAV2-CMV-hPEDF can relieve BRB breakdown in STZ-induced diabetic rats for 6 months. The effect is associated with downregulation of retinal VEGF mRNA and ICAM-1 expression and a reduction in the loss of retinal occludin induced by diabetes. The approach of gene transfer may reduce diabetic macular edema, providing long-term protection for diabetic patients at risk of macular edema.
authors.affiliation: Department of Ophthalmology, First affiliated Hospital of China Medical University, Shenyang, Liaoning, China. yh7242@hotmail
authors.forename: Hai
authors.initials: H
authors.lastname: Yu
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Jiang
mesh_terms: D000818:Animals; D001813:Blood-Retinal Barrier / Q000473:pathology*; D000229:Dependovirus / Q000235:genetics*; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000473:pathology*; D015536:Down-Regulation / Q000235:genetics; D005136:Eye Proteins / Q000008:administration & dosage* / Q000235:genetics / Q000378:metabolism; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D058449:Intravitreal Injections; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D009414:Nerve Growth Factors / Q000008:administration & dosage* / Q000235:genetics / Q000378:metabolism; D062793:Occludin; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000378:metabolism / Q000473:pathology; D015843:Serpins / Q000008:administration & dosage* / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation / Q000235:genetics; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D000099174:Pigment Epithelium-Derived Factor
chemical_list: D005136:Eye Proteins; D049452:Green Fluorescent Proteins; D018799:Intercellular Adhesion Molecule-1; D008565:Membrane Proteins; D009414:Nerve Growth Factors; D062793:Occludin; D015843:Serpins; D042461:Vascular Endothelial Growth Factor A; D000099174:Pigment Epithelium-Derived Factor; C568985:OCLN protein, human; C568987:Ocln protein, rat