Placenta growth factor and vascular endothelial growth factor in the vitreous of patients with proliferative vitreoretinopathy

Abstract

Abstract: : Purpose: Placenta growth factor (PlGF) is a close homologue of vascular endothelial growth factor (VEGF) and shares receptors with VEGF. The receptor for VEGF and PlGF (fms–like tyrosine kinase: flt–1) is identified in the epiretinal membranes of PVR, and flt–1 mRNA and protein are identified in cultured retinal pigment epithelial cells and retinal glia. These results suggest the possible implication of PlGF in the pathogenesis of PVR. We attempted to determine whether intravitreous PlGF levels are elevated in PVR and whether they correlate with VEGF levels. Methods: We assayed PlGF and VEGF levels in vitreous samples from 45 consecutive patients with PVR (11 eyes), rhegmatogenous retinal detachment (RRD) without PVR (15 eyes), and macular hole (controls, 19 eyes) that underwent pars plana vitrectomy. Undiluted vitreous samples were collected during the vitrectomy before intraocular infusion. Vitreous PlGF and VEGF concentrations were measured using an enzyme–linked immunosorbent assay. Results: PlGF levels (mean±SD) were significantly higher in PVR (20.0±12.0 pg/ml) than in RRD (10.0±4.0 pg/ml) and in the controls (7.5±1.3 pg/ml) (P=0.0003, P<0.0001, respectively). VEGF levels were also significantly higher in PVR (178.4±149.1 pg/ml) than in RRD (68.2±60.8 pg/ml) and in the controls (9.1±0.2 pg/ml) (P=0.0013, P<0.0001, respectively). PlGF levels significantly correlated with VEGF levels in all the subjects (r=0.893, P<0.0001). Conclusions: The results indicate increased intravitreous PlGF levels in PVR eyes and a significant correlation between PlGF and VEGF levels, suggesting that PlGF has a cooperative role with VEGF in the pathogenesis of PVR.

Keywords: growth factors/growth factor receptors • proliferative vitreoretinopathy • vitreous