LOCALIZATION OF VASCULAR ENDOTHELIAL GROWTH-FACTOR IN HUMAN RETINA AND CHOROID

Objective: To examine the distribution and relative levels of vascular endothelial growth factor (VEGF) in the nondiabetic and preproliferat ive diabetic human retina and choroid. Methods: Immunohistochemical lo calization was performed on frozen sections from cryopreserved postmor tem human tissue using a polyclonal antibody against VEGF and a strept avidin peroxidase system. Eyes from 5 subjects without diabetes and 8 subjects with diabetes were examined and analyzed using a 7-point immu nohistochemical grading system. Results: In subjects without diabetes, weak or no VEGF immunoreactivity was associated with retinal blood ve ssels. In subjects with diabetes, we found significantly increased imm unoreactivity in the retinal vascular endothelium and blood vessel wal ls. Vascular endothelial growth factor immunoreactivity was also assoc iated with intravascular leukocytes in subjects with and without diabe tes. In the choroid of subjects without diabetes, immunoreactivity was almost exclusively associated with intravascular leukocytes, whereas in diabetic subjects, immunoreactivity was localized within choriocapi llaris endothelium, choroidal neovascular endothelium, and migrating r etinal pigment epithelium cells. Conclusions: The observed increase in VEGF immunoreactivity in the diabetic retina and choroid suggests tha t VEGF may contribute to 2 well-documented events during retinopathy: increased vascular permeability and angiogenesis.