Intravitreous high expression level of netrin-1 in patients with proliferative diabetic retinopathy.

Abstract

To investigate the significance of netrin-1 and vascular endothelial growth factor (VEGF) in the pathogenesis of retinal angiogenesis, the levels of netrin-1 and VEGF in the vitreous fluid and serum of the proliferative diabetic retinopathy (PDR) and non-proliferative diabetic retinopathy (non-PDR) patients were measured. We then determined the netrin-1 and VEGF expression in the oxygen induced retinopathy (OIR) mice retinas. A total of 18 eyes from 18 patients were included in our study and 10 of them were collected from PDR patients and 8 from non-PDR patients. Undiluted vitreous fluid samples were collected during pars plana vitrectomy. Appropriate blood samples were collected if possible. Netrin-1 and VEGF levels in the vitreous fluid and plasma were determined by Enzyme-linked Immunosorbent Assays. OIR mice models were established, and netrin-1 and VEGF levels were determined by immunohistochemistry analysis. The levels of netrin-1 and VEGF in the vitreous of PDR patients were significantly higher than those in the controls (Mediannetrin-1=509.94 vs. 85.91 pg/ml, P<0.001 and Median VEGF=762.60 vs. 77.52 pg pg/ml, P<0.001). Netrin-1 was mainly expressed in GCL and INL of the retina in mice. Both netrin-1 and VEGF were up-regulated in OIR mice. Netrin-1 and VEGF levels were elevated in vitreous fluid of the PDR patients and the OIR mice retinas. Therefore, netrin-1 may play important roles in pathological retinal angiogenesis.