High Levels of Pigment Epithelial-Derived Factor (PEDF) in Blood of Patients With Diabetic Retinopathy

Abstract

Purpose:: Pigment epithelium-derived factor (PEDF) is a neurotrophic factor, and a strong inhibitor of angiogenesis. Previous studies reported that eyes with diabetic retinopathy have low levels of intraocular PEDF. However the PEDF levels in the blood of diabetes have still not been determined. The aim of this study was to determine the plasma levels of PEDF in diabetic patients and to determine whether the level of plasma PEDF was correlated with the stage of diabetic retinopathy.

Methods:: A total of 276 Japanese were studied; 243 had type 2 diabetic mellitus and 33 were healthy controls. The plasma level of PEDF was measured by ELISA, and the stage of diabetic retinopathy was determined by ophthalmic examinations. The relationship between the PEDF levels and diabetic status was evaluated. The data were analyzed statistically with the one way analysis of variance (ANOVA) and Pearson's product moment correlation coefficient (r).

Results:: The PEDF level in the plasma increased significantly with increasing age in the controls (r = 0.62) but not in the diabetic group. The mean plasma level of PEDF in diabetic patients (6.66 ± 0.38 µg/ml; mean ± SEM) was significantly higher than that in controls (4.38 ± 0.59 µg/ml, P =0.03). The plasma PEDF levels increased as the stage of diabetic retinopathy advanced; 5.29 ± 1.14 µg/ml in eyes with non-diabetic retinopathy (NDR)(n = 20), 5.07 ± 0.72 µg/ml with simple diabetic retinopathy (SDR) (n= 37), 6.61 ± 0.72 µg/ml with pre-proliferative diabetic retinopathy (PPDR) (n = 98), and 7.69 ± 0.63 µg/ml with proliferative diabetic retinopathy (PDR) (n = 88). The level in patients with PDR was significantly higher than that of controls (P=0.04).

Conclusions:: PEDF may be elevated to counteract the altered systemic metabolism, and the PEDF level in the blood is elevated in diabetic patients especially in those with proliferative diabetic retinopathy.None. #

Keywords: diabetic retinopathy • neovascularization • growth factors/growth factor receptors