Serum levels of pigment epithelium-derived factor (PEDF) are positively associated with visceral adiposity in Japanese patients with type 2 diabetes

Background: Pigment epithelium-derived factor (PEDF) inhibits endothelial cell injury. Further, serum levels of PEDF are elevated in the metabolic syndrome. These observations suggest that PEDF may be elevated as a counter-system against vascular cell damage in the metabolic syndrome. However, little is known about the regulation of PEDF in patients with diabetes. In order to clarify the determinants of serum PEDF, here, we examined the relationship between the 1-year changes in PEDF levels and those in anthropometric and metabolic variables in type 2 diabetic patients. Methods: Eighty-six consecutive outpatients with type 2 diabetes underwent a complete history and physical examination, determination of blood chemistries, and serum levels of PEDF at baseline and 1 year after. PEDF gene expression in cultured subcutaneous or omental adipocytes were analysed by quantitative real-time reverse transcription-polymerase chain reactions. Results: Multiple regression analyses revealed that waist circumference, triglycerides, creatinine, and TNF-α were independently associated with PEDF. Further, the percent changes in serum levels of PEDF during 1-year observational periods were positively correlated with those of BMI. In addition, PEDF mRNA levels in cultured adipocytes were increased in parallel to the BMI values of subjects from whom adipocytes were derived, especially in omental adipocytes. Conclusion: These results demonstrated that serum levels of PEDF were positively associated with metabolic components and TNF-α in Japanese patients with type 2 diabetes. Our present study suggests that PEDF may be generated from adipose tissues and play some role in visceral obesity in type 2 diabetic patients.