Serum FGF21 in girls with anorexia nervosa - comparison to normal weight and obese female adolescents.

BACKGROUND: Fibroblast growth factor 21 (FGF21) is a hepatokine, myokine and adipokine of a potent influence to energy homeostasis. Data according its serum concentrations in AN are contradictory.
OBJECTIVES: Analysis of serum FGF21 in girls with acute anorexia nervosa and comparison the results with normal weight and obese female adolescents considering their nutritional status, carbohydrate and lipid metabolism.
METHODS: Serum FGF21 concentrations were evaluated using commercially available ELISA kit in 32 Polish girls with restrictive AN (AN), 29 girls with obesity (O) and 21 healthy controls (C). Anthropometric measurements (weight, height, BMI) and laboratory assays (serum fasting glucose, insulin, HOMA-IR, total cholesterol, HDL, LDL, triglycerides, C-reactive protein) were performed.
RESULTS: Mean serum FGF-21 in the AN group was significantly lower, whereas in the O group it was significantly higher than in healthy controls. In all examined girls significant positive correlations between FGF21 and BMI were noted. We also observed significant positive relationships between serum FGF21 levels and fasting glucose, triglycerides, CRP, insulin and HOMA-IR. In all examined girls serum concentrations of this hormone correlated negatively with age and HDL-cholesterol levels.
CONCLUSIONS: 1) Serum FGF21 concentrations are decreased in AN and elevated in obesity. They are independently and positively related to BMI and insulin resistance; 2) Decreased serum FGF21 in AN may support the maintenance of normal blood glucose through adjustment the insulin levels and insulin sensitivity; 3) Elevated FGF21 levels in obesity may be considered adaptive mechanism preventing insulin resistance and its metabolic consequences.