Circulating Pigment Epithelium-Derived Factor Levels Are Associated with Insulin Resistance and Decrease after Weight Loss

Objective: We aimed to study circulating pigment epithelium-derived factor (PEDF) in vivo in association with insulin resistance and in vitro in human adipocytes. Methods: Circulating PEDF (ELISA) and metabolic profile were assessed in 125 Caucasian men. PEDF levels were also assessed in an independent cohort of subjects (n = 33) to study the effects of changing insulin action. PEDF gene expression and secretion were measured during differentiation of human preadipocytes. Results: In all subjects, PEDF was positively associated with body mass index (r = 0.326; P < 0.0001), waist-to-hip ratio (r = 0.380; P < 0.0001), HbA1c, and fasting triglycerides and negatively with insulin sensitivity (r = −0.320; P < 0.0001). PEDF levels were significantly increased in subjects with altered glucose tolerance and type 2 diabetes. Of the inflammatory markers measured, PEDF levels were positively associated with serum soluble TNF-α receptor 1 and IL-10 in obese subjects. Interestingly, weight loss led to significantly de...