Serum levels of pigment epithelium-derived factor (PEDF) are positively associated with acanthosis nigricans in obese adolescents

Introduction:  Circulating pigment epithelium-derived factor, or serine protease inhibitor F1, is upregulated during adipogenesis, contributing to obesity-induced insulin resistance. Furthermore, pigment epithelium-derived factor is abundant in stage I melanosomes and has been reported to increase pigment granules and the appearance of mature melanosomes in retinal pigment epithelium. As acanthosis nigricans is a well-recognized clinical marker of insulin resistance, we hypothesized that increased pigment epithelium-derived factor might be associated with the generation of acanthosis nigricans. Methods:  Acanthosis nigricans, anthropometric measurements, circulating total PEDF and metabolic profiles were assessed in 28 obese adolescents in a hospital-based obesity clinic. Results:  Subjects with acanthosis nigricans (n = 10) showed greater plasma levels of pigment epithelium-derived factor (PEDF) than those without [geometric mean 23.55 (range 15.2-40.2) vs. 9.01 (range 5.5-18.7) μg/ml; P