Evaluation of concentrations of FGF-21 - a new adipocytokine in type 2 diabetes

Abstract

Introduction: Fibroblast growth factor 21 FGF-21 is a newly discovered adipocytokine which may play a vital role in improvement of insulin sensitivity and pathogenesis of type 2 diabetes. The aim of the study was to assess FGF-21 concentrations in the serum of patients with type 2 diabetes, in comparison to a control group, and evaluate the possible relationships between the studied cytokine and selected clinical and biochemical parameters
Material and methods: The study was conducted in 64 patients with type 2 diabetes, 28 women and 36 men aged 47-70 (median age 61.5), with a median duration of diabetes of 8.5 years. In fasting serum samples, concentrations of glucose, insulin, lipids profile parameters, creatinine, C-reactive protein (CRP), fibrinogen, HbA_1c, adiponectin, and FGF-21 were determined. The control group comprised 20 healthy persons matched for age to the study group, with no disturbances in carbohydrate metabolism: 14 women and 8 men.
Results: We found significant differences concerning the medians of body mass index (BMI) 32.4 kg/m² v. 24.1 kg/m², p < 0.001; waist circumference 114 cm v. 81 cm, p < 0.001; HDL cholesterol 42.5 mg/dl v. 62.5 mg/dl, p < 0.001; triglyceride (TG) 152 mg/dl v. 99 mg/dl, p < 0.01 in the studied group, in comparison with the control group, respectively. In patients with diabetes, median FGF-21 concentration was 239.9 pg/ml and was significantly greater in comparison to the control group: 112.6 pg/ml p < 0.01. Median adiponectin concentration in patients with type 2 diabetes was significantly lower in comparison to the control group, 7.5 ng/ml v. 9.95 ng/ml, p < 0.05. Significant correlations between FGF-21 concentrations and adiponectin (r = -0.24, p < 0.05), weight (r = 0.27, p < 0.05), glucose (r = 0.27, p < 0.05), HDL cholesterol (r = -0.26, p < 0.05), TG (r = 0.27, p < 005), and estimated glomerular filtration rate (eGFR) (r = -0.28, p < 0.05) were observed. No significant correlations between FGF-21 and parameters of metabolic control, markers of inflammatory status, and insulin resistance, or the presence of vascular complications of diabetes, were noticed.
Conclusions: On the basis of the conducted studies it can be concluded that the greater FGF-21 concentration observed in the examined group of patients with type 2 diabetes may result from a compensatory reaction to metabolic disturbances or tissue resistance to this cytokine. The negative correlation between FGF-21 and eGFR suggests renal elimination of the examined compound.
(Pol J Endocrinol 2010; 61 (1): 50-54)