[Adipocytokines: potential biomarkers for childhood obesity and anorexia nervosa]

Adipose tissue is now considered an important endocrine organ that secretes a large number of physiologically active peptides affecting metabolic homeostasis of human body: they are collectively referred to as adipocytokines. Leptin is a key hormone in the regulation of food intake, energy expenditure, neuroendocrine and immune function. Leptin is related with obesity and its metabolic disorders; starvation-induced depletion of fat stores is accompanied by alterations of circulating adipocytokines that may have potential repercussions in the pathophysiology of anorexia nervosa. Adiponectin enhances insulin sensitivity, controls body weight, prevents atherosclerosis and negatively regulates immune functions. Plasma adiponectin relates inversely to adiposity and reflects the sequelae of accumulation of excess adiposity. Resistin is a protein hormone produced both by adipocytes and immunocompetent cells that affect fuel homeostasis and insulin action. Plasma resistin levels are decreased in anorectic patients, while plasma adiponectin levels are increased. Plasma ghrelin levels present opposite changes in obesity and anorexia nervosa, suggesting that ghrelin is a good marker of nutritional status. Visfatin shows to correlate with visceral fat mass in patients with obesity. Its possible role in patients with anorexia nervosa is unknown. In conclusion, obesity is defined as a state of low-grade inflammation, which is associated with increased leptin, resistin and ghrelin levels and decreased adiponectin levels; anorexia nervosa is characterized by opposite changes. Finally, plasma adipocytokines levels can represent a sensitive parameter of nutritional status that reflects changes in the level of body fat in children and adolescents with obesity and anorexia nervosa.