Adipocytokines in anorexia nervosa: a review focusing on leptin and adiponectin

Adipose tissue secretes a large number of physiologically active peptides that often share structural properties with cytokines, and are therefore collectively referred to as "adipocytokines". Some of these are almost exclusively secreted by adipose tissue. Leptin, adiponectin and resistin are specific fat-derived hormones that affect fuel homeostasis and insulin action, and may also be involved in hematopoiesis and immune functions. Anorexia nervosa is characterized by chronic self-starvation and severe weight loss, mainly at the expense of adipose tissue. Starvation-induced depletion of fat stores is accompanied by alterations of circulating adipocytokines. Plasma leptin and likely resistin levels are decreased in anorectic patients, while plasma adiponectin levels are increased. These alterations may have potential repercussions in the pathophysiology of anorexia nervosa. Thus, low leptin and high adiponectin may separately or in concert contribute to altered hematopoiesis and immunity, enhanced insulin sensitivity, neuroendocrine disturbances or osteopenia in anorexia nervosa.