title: Vascular endothelial growth factor and vascular permeability changes in human diabetic retinopathy.
abstract: OBJECTIVE
  The authors used histochemical analysis to determine whether increased vascular endothelial growth factor (VEGF) immunoreactivity in diabetic retinal vessels is related to increased vascular permeability, as indicated by human serum albumin (HSA) immunostaining, or to presumed retinal hypoxia as demonstrated by decreased vascularity. A correlation between VEGF and HSA in cryosections with angiopathic changes in the adenosine diphosphatase (ADPase) flat-embedded fellow retinas was sought. Because VEGF is a heparin-binding protein, the relation between VEGF and heparan sulfate proteoglycan (HSPG) immunoreactivities was also investigated.
  
  
  METHODS
  Cryopreserved eyes from 18 diabetic and 9 nondiabetic subjects removed after death were sectioned and immunohistochemical analysis was performed with antibodies against VEGF, HSA, HSPG, vWf (von Willebrand factor), and collagen IV. The fellow retinas were prepared by our ADPase flat-embedding technique to determine the degree of diabetic retinopathy. The number of positive vessels for each antibody and antibody localizations were determined by light microscopy.
  
  
  RESULTS
  The average number of VEGF-stained vessels in diabetic retinas was significantly higher than in nondiabetic retinas (P = 0.04). In diabetic retinas, there was a positive correlation between the distribution of VEGF-positive vessels and the distribution of HSA- and HSPG-positive vessels. No such correlation was observed in nondiabetic eyes. In many cases, HSPG immunoreactivity appeared colocalized with VEGF immunoreactivity, suggesting VEGF binding to HSPG. The comparison with the ADPase flat-embedded fellow retinas suggested that increased VEGF immunoreactivity and vascular permeability may occur before morphologic changes in the vasculature.
  
  
  CONCLUSIONS
  Vascular endothelial growth factor immunoreactivity was correlated with increased vascular permeability to macromolecules and appears to be increased in diabetic subjects before the onset of retinopathy.
authors.affiliation: Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: M K
authors.initials: MK
authors.lastname: Mathews
authors.forename: C
authors.initials: C
authors.lastname: Merges
authors.forename: D S
authors.initials: DS
authors.lastname: McLeod
authors.forename: G A
authors.initials: GA
authors.lastname: Lutty
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001081:Apyrase / Q000378:metabolism; D002199:Capillary Permeability; D003922:Diabetes Mellitus, Type 1 / Q000150:complications; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003930:Diabetic Retinopathy / Q000150:complications / Q000378:metabolism*; D016228:Endothelial Growth Factors / Q000378:metabolism*; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D008222:Lymphokines / Q000378:metabolism*; D008875:Middle Aged; D012171:Retinal Vessels / Q000378:metabolism*; D012709:Serum Albumin / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: D016228:Endothelial Growth Factors; D019812:Heparan Sulfate Proteoglycans; D008222:Lymphokines; D012709:Serum Albumin; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D001081:Apyrase