Therapy insight: adipocytokines in metabolic syndrome and related cardiovascular disease

Abdominal fat accumulation has been shown to play crucial roles in the development of metabolic syndrome. Visceral fat accumulation particularly is closely correlated to the development of cardiovascular disease and obesity-related disorders such as diabetes mellitus, hyperlipidemia and hypertension. Given these clinical findings, the functions of adipocytes have been intensively investigated in the past 10 years, and have been revealed to act as endocrine cells that secrete various bioactive substances termed adipocytokines. Among adipocytokines, tumor-necrosis factor-alpha, plasminogen activator inhibitor type 1 and heparin-binding epidermal growth factor-like growth factor are produced in adipocytes as well as other organs, and contribute to the development of vascular diseases. Visfatin has been identified as a visceral-fat-specific protein that might be involved in the development of obesity-related diseases, such as diabetes mellitus and cardiovascular disease. In contrast to these adipocytokines, adiponectin, which is an adipose-tissue-specific, collagen-like protein, has been noted as an important antiatherogenic and antidiabetic protein, or as an anti-inflammatory protein. The functions of adipocytokine secretion might be regulated dynamically by nutritional state. Visceral fat accumulation causes dysregulation of adipocyte functions, including oversecretion of tumor-necrosis factor-alpha, plasminogen activator inhibitor type I and heparin-binding epidermal growth factor-like growth factor, and hyposecretion of adiponectin, which results in the development of a variety of metabolic and circulatory diseases. In this review, the importance of adipocytokines, particularly adiponectin, is discussed with respect to cardiovascular diseases.