Plasma VEGF and soluble VEGF receptor FLT-1 in proliferative retinopathy: Relationship to endothelial dysfunction and laser treatment

PURPOSE. To study plasma levels of vascular endothelial growth factor (VEGF , an index of angiogenesis), its soluble receptor (sFlt-1) and von Willebra nd factor (vWf, an index of endothelial damage or dysfunction) in patients with proliferative retinopathy and corresponding changes in plasma levels a fter pan-retinal photocoagulation (PRP). METHODS. Eighteen patients (10 men; age, 57 +/- 16 years, mean +/- SD) with proliferative retinopathy secondary to diabetes (n = 13) and ischemic reti nal vein occlusion (n = 5) with no previous PRP therapy were studied. Blood samples were obtained before and at 4 months after the last PRP session. B aseline (prelaser) plasma levels of VEGF, sFlt-1, and vWf (all by ELISA) we re compared with levels in 16 diabetic patients with background retinopathy ("hospital controls"), and 18 healthy, age- and, sex-matched "healthy cont rols." RESULTS. Patients with proliferative retinopathy had significantly raised p lasma VEGF when compared with both control groups (P = 0.001). Patients wit h proliferative retinopathy and hospital controls had significantly raised plasma vWf levels when compared with healthy controls (P = 0.012). There wa s no difference in sFlt-1 levels between patients and controls (P = 0.162). After PRP, there was a significant reduction in plasma VEGF levels at 4 mo nths' follow-up (P < 0.001), but no significant changes in plasma sFlt-1 or vWf levels. Patients with complete resolution of neovascularization had a trend toward lower median VEGF levels (80 versus 150 pg/ml, P = 0.062), but vWf levels (P = 0.50) and sFlt-1 (P = 0.479) were not statistically differ ent. Baseline VEGF and sFlt-1 levels were significantly correlated (Spearma n r = 0.505, P = 0.032) but after PRP at 4 months' follow-up, this was no l onger significant (r = -0.269, P = 0.28). CONCLUSIONS. In this pilot study, patients with proliferative retinopathy d emonstrate elevated peripheral markers of angiogenesis and endothelial dysf unction, suggesting a role for these processes in the pathogenesis of this condition. A fall in levels of VEGF after successful laser treatment may pr ovide an opportunity for monitoring disease progression or relapse via a bl ood sample.