Effect of weight loss on serum pigment epithelium-derived factor levels.

Background Cumulating evidence suggests that the broadly acting neurotrophic pigment epithelium-derived factor is associated with visceral adiposity, the metabolic syndrome, diabetes and exerts beneficial effects on atherosclerosis. To further elucidate the relationship between pigment epithelium-derived factor and metabolic perturbations characteristic of obesity, we examined the effect of pronounced weight loss on serum levels of pigment epithelium-derived factor. Materials and methods Thirty-six severely obese adults were examined before and 18 months after bariatric surgery. Abdominal fat distribution was determined by ultrasound, metabolic parameters by standard methods, pro-inflammatory biomarkers and serum pigment epithelium-derived factor levels by enzyme-linked immunosorbent assay. Results Bariatric surgery resulted in a mean body mass index (BMI) reduction of 9.0 +/- 5.0 kg m(-2) and concomitant improvements in glucose homoeostasis and lipid profile. Pigment epithelium-derived factor serum levels decreased from a median 11.0 mu g mL(-1) (interquartile range: 3.8) to 9.2 mu g mL(-1) (interquartile range: 4.5) (P < 0.0001). In univariate analysis, relative change in pigment epithelium-derived factor levels was significantly associated with change in weight, BMI, fat mass, visceral fat diameter, insulin, homoeostasis model for insulin resistance, triglyceride and leptin levels (all r > 0.370, P < 0.05). No associations were observed for C-reactive protein, interleukin-6 or tumour necrosis factor alpha. After adjustment for age, sex and smoking status, associations remained significant. Conclusions The beneficial effects of bariatric surgery-induced pronounced weight loss on glucose homoeostasis may partially be attributable to visceral adipose tissue reduction and concomitantly decreasing pigment epithelium-derived factor concentrations.