Plasma Pigment Epithelium-Derived Factor (PEDF) Levels and Diabetic Status in Patients With Diabetic Retinopathy

Abstract

Purpose: : Pigment epithelium-derived factor (PEDF) is a neurotrophic factor and a strong inhibitor of angiogenesis. Previous studies showed that eyes with diabetic retinopathy have low levels of intraocular PEDF. On the other hand, we found that the level of PEDF in the blood was high in diabetic patients. The aim of this study was to determine the relationship between plasma PEDF and diabetic status in patients with diabetic retinopathy.

Methods: : This study was designed as a cross-sectional study. A total of 145 Japanese were studied; 112 had type 2 diabetes 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 data were analyzed statistically with the one way analysis of variance (ANOVA) and multiple regression analysis to evaluate the factors that have an effect on plasma PEDF levels.

Results: : The plasma PEDF level in diabetic patients (6.68 ± 0.54 µg/ml; mean ± SEM) was significantly higher than that in controls (4.38 ± 0.59 µg/ml, P=0.03). The level of plasma PEDF was 5.84 ± 1.72 µg/ml in eyes with NDR (n = 12), 6.05 ± 1.02 µg/ml with mild to moderate nonproliferative diabetic retinopathy (M-NPDR) (n= 16), 5.95 ± 0.80 µg/ml with severe nonproliferative diabetic retinopathy (S-NPDR) (n = 39), and 7.79 ± 0.98µg/ml with PDR (n = 45). The PEDF level was especially higher in patients with PDR than that in controls (P=0.005). The gender (P=0.03), blood urea nitrogen (P=0.005), and triglycerides (P=0.04) were significant and independent determinants of plasma PEDF levels in diabetic patients, but age (P = 0.84), HbA1c (7.5 ± 0.2 %, P = 0.83), and insulin treatment (P = 0.91) were not significantly related.

Conclusions: : The PEDF level in the plasma was significantly elevated in diabetic patients, especially those with PDR. PEDF is most likely associated with the metabolism in patients with diabetes mellitus.

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