Biochemical abnormalities in vitreous of humans with proliferative diabetic retinopathy
J. Sebag, B. Buckingham, M. A. Charles and K. Reiser
Doheny Eye Institute, University of Southern California, Los Angeles.
Vitreous changes in diabetes can exacerbate proliferative diabetic
retinopathy. These changes may be due to the effects of diabetes on
vitreous collagen. Vitreous samples from 19 patients with proliferative
diabetic retinopathy and 23 patients without diabetes were analyzed for
collagen crosslinks, as well as for the early glycation products,
glucitolyllysine and glucitolylhydroxylysine. Fluorometry was performed to
measure advanced glycation end products. Vitreous collagen derived from
diabetic patients was found to have significantly higher levels of the
crosslink dihydroxylysinonorleucine (3.15 vs 1.24 mol/mol collagen,
P<.01) than that of control subjects. Early glycation products were
elevated in diabetic vitreous (1.65 vs 0.54 mol/mol collagen, P<.05).
Levels of advanced glycation end products were 20 times higher in diabetic
vitreous compared with the vitreous of controls. These diabetes-induced
alterations of human vitreous may be of particular importance given the
role of vitreous in proliferative diabetic retinopathy and vision loss.
