Vitreous levels of vasohibin-1 and vascular endothelial growth factor in patients with proliferative diabetic retinopathy

Excerpt

To the Editor: Intraocular neovascularisation develops in many ischaemic retinal diseases, e.g. diabetic retinopathy, ischaemic retinal vein occlusion and retinopathy of prematurity. The new vessels are fragile and often rupture, leading to vitreous haemorrhage, tractional retinal detachment, neovascular glaucoma and subsequent vision decrease. The formation of new vessels is dependent on a local balance of stimulators and inhibitors of angiogenesis [1]. Among the stimulators, vascular endothelial growth factor (VEGF) has been shown to play a major role in mediating active neovascularisation in patients with diabetic retinopathy [2]. In addition, several studies have shown that the concentration of VEGF in the intraocular fluids was significantly elevated in eyes with proliferative diabetic retinopathy (PDR) [3‐5]. On the other hand, pigment epithelium-derived factor (PEDF) is a potent inhibitor of angiogenesis, and lower levels of PEDF have been found in the vitreous of eyes with active diabetic retinopathy [4]. It has also been shown that the vitreous level of endostatin, another inhibitor of angiogenesis, is correlated with the level of VEGF and that endostatin is produced in the fibrovascular membrane of eyes with PDR [5]. …