Serum Levels of Adipokines in Type 2 Diabetic Subjects: the Relationships with Adipose Tissue Distribution and Microvasculature

Abstract

The aim: to determine the relationships between serum levels of adipokines, body fat distribution, and the density and ultrastructure of blood and lymphatic microvessels in subcutaneous adipose tissue (AT) in type 2 diabetic subjects. Materials and Methods: We observed 125 patients, including 82 ones with obesity, and 30 lean non-diabetic individuals. The concentrations of leptin, resistin, visfatin, adipsin, and adiponectin in the fasting serum were determined by Multiplex analysis. The fat mass and AT distribution was assessed by DEXA. The samples of subcutaneous abdominal AT were obtained with the knife biopsy in 25 patients and in 15 healthy subjects. Immunohistochemistry for biomarkers CD-34, podoplanin and LYVE-1 was applied to identify the blood and lymphatic microvessels. Results: Patients with diabetes, as compared to control, had significantly higher levels of leptin (p=0.004), resistin (p<0.0001), adipsin (p<0.0001) and visfatin (p=0.0003). The concentrations of leptin, resistin and adipsin were associated with total fat mass. The levels of resistin and adiponectin demonstrated relationships with truncal and central abdominal fat mass. The increase in leptin levels in patients with type 2 diabetes and obesity was associated with a decrease in the volume and numeral density of the blood and lymph microvessels in the subcutaneous fat (r=-0.63, p=0.02; r=-0.55, p=0.05). The level of resistin was negatively correlated with the numeral density of lymphatic vessels (r=-0.59, p=0.03). Conclusion: The levels of circulating adipokines in patients with type 2 diabetes are related differently with body fat distribution and AT microvessel density.