Elevated plasma pigment epithelium-derived factor in children with type 2 diabetes mellitus is attributable to obesity

BackgroundPigment epithelium-derived factor (PEDF) is a member of the serpin family secreted by adipocytes. Plasma PEDF is increased in obese children and adults. Adults with type 2 diabetes mellitus (T2DM) have higher circulating PEDF but there are no reports in children with T2DM. ObjectiveTo compare PEDF concentration in children with T2DM to normal weight and obese children without T2DM and determine associations with anthropometric or serum factors. MethodsParticipants were 34 obese children with T2DM diagnosed by American Diabetes Association (ADA) criteria, 61 normal weight [body mass index (BMI) 25-75 percentile] and 63 obese (BMI 95 percentile) children of age 8-18 yr. Plasma PEDF was measured in fasting plasma samples. Anthropometric, serum, and body composition (dual-energy x-ray absorptiometry, DXA) data were obtained for each subject to identify potential predictor variables. ResultsPEDF was 55% higher (p = 0.001) in the T2DM group compared with normal weight children, but did not differ from obese children. In the T2DM group, fat mass and lean mass both individually predicted PEDF (r(2) = 0.22 and 0.17, p = 0.02 and p < 0.01, respectively). PEDF was positively correlated with homeostatic model assessment - insulin resistance (HOMA-IR) when all groups were combined (r(2) = 0.15, p<0.001). ConclusionsPlasma PEDF was similar in the T2DM and obese groups, therefore, obesity, rather than diabetes, may account for the higher PEDF in children with T2DM compared with normal weight children. PEDF was positively associated with both lean mass and fat mass both of which may contribute to the circulating level of the protein, and potentially to PEDF's association with insulin resistance in obese children with and without diabetes.