VEGF localisation in diabetic retinopathy.
OBJECTIVE
To determine the staining pattern of vascular endothelial growth factor (VEGF) at different stages of diabetic retinopathy (including post-laser photocoagulation) and to compare staining in excised fibrovascular and fibrocellular (non-diabetic) preretinal membranes.


METHODS
Immunohistochemical localisation of VEGF, using antibodies raised against VEGF165 and VEGF121,165,189, was carried out on specimens of normal human retina (n = 15), diabetic retinas ((a) with no overt retinopathy (n = 19), (b) with intraretinal vascular abnormalities but no proliferative retinopathy (n = 6), (c) with active proliferative retinopathy (n = 6), (d) with no residual proliferative retinopathy after photocoagulation therapy (n = 15)), excised diabetic fibrovascular membranes (n = 19), and non-diabetic fibrocellular membranes (n = 7). The degree and pattern of immunostaining was recorded.


RESULTS
In general, VEGF was absent from the majority of normal retinas. VEGF staining was apparent in most diabetic tissues but the staining pattern was dependent on both the specificity of the antibody used and the category of tissue. Staining with the VEGF165 antibody was generally confined to endothelial cells adn perivascular regions while the VEGF121,165,189 antibody was also associated with extravascular components of the inner retina. Intensity of immunostaining of diabetic eyes was dependent on the severity of retinopathy being least in diabetics with no overt retinopathy and greatest in retinas with proliferative retinopathy. Interestingly, the intensity of immunostaining in diabetic retinas which had undergone laser surgery for proliferative retinopathy was reduced to basal levels. Moderate to intense immunostaining was observed in all fibrovascular and fibrocellular membranes examined.


CONCLUSIONS
This study supports a circumstantial role for VEGF in the pathogenesis of both the preclinical and proliferative stages of diabetic retinopathy.
University Department of Ophthalmology, Manchester Royal Eye Hospital.
M
M
Boulton
D
D
Foreman
G
G
Williams
D
D
McLeod
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002829:Choroid / Q000378:metabolism; D003920:Diabetes Mellitus / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000378:metabolism* / Q000601:surgery; D018450:Disease Progression; D016228:Endothelial Growth Factors / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D017075:Laser Coagulation; D008222:Lymphokines / Q000378:metabolism*; D008875:Middle Aged; D012160:Retina / Q000378:metabolism; D012171:Retinal Vessels / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008222:Lymphokines; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors