Background: Anti-vascular endothelial growth factor (anti-VEGF) therapy has revolutionized the treatment of severe diabetic retinopathy (DR) , but significant subset of patients showed inadequate response to anti-VEGF. We have previously reported that retinol binding protein 3 (RBP3) prevented hyperglycemia induced retinal pathologies and progression to severe DR. Hypothesis: RBP3 and Anti-VEGF have differential protective profiles in preventing retinal dysfunctions induced by diabetes.

Methods and Results: Recombinant human RBP3 (rhRBP3, 5ug/ml) and anti-VEGF (Avastin, 250mg/ml) inhibited VEGF-induced retinal vascular permeability (RVP) by 70% when intravitreal injections were given together in Lewis rats (P < 0.01) . After 2 months of diabetes induced by streptozotocin (STZ) , intravitreal injection of rhRBP3 and anti-VEGF for 3 days suppressed RVP by 64% and 53% (P < 0.01) in Lewis rats. This was accompanied by reductions of VEGF levels by both proteins. Electroretinogram (ERG) amplitudes of A wave, B wave, C wave were decreased in rats after 2 months of diabetes (P < 0.01) . rhRBP3 increased amplitudes of C wave (P < 0.01) , while anti-VEGF did not improve any waveforms. Furthermore, rhRBP3 decreased retinal mRNA expression of Cd11b and Tnfa (P =0.1) in diabetic rats. In cultured primary bovine Müller cells, rhRBP3 decreased mRNA expressions of Tnfa and Il-6 induced by high glucose (25mM) (P < 0.01) , whereas, anti-VEGF showed no effect. Metabolic function studies using Seahorse assays showed that isolated retina from intravitreal rhRBP3 treated rats exhibited reduced glycolysis rate in ECAR while anti-VEGF treatments had no effects.

Conclusions: Both intravitreal anti-VEGF and RBP3 treatments normalized retinal vascular dysfunctions caused by diabetes. However, only RBP3 reversed abnormal neural-retinal dysfunctions and elevated inflammatory cytokines induced by hyperglycemia, possible by decreasing glucose uptake and glycolysis levels in retinal cells.


Q.Li: None. S.Onizuka: None. K.Park: None. H.Park: None. Q.Li: None. W.Fickweiler: None. J.Fu: None. I.Wu: None. G.L.King: Advisory Panel; Medtronic, Research Support; Janssen Pharmaceuticals, Inc.

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at