Metabolic syndrome is a highly atherogenic state in which
hyperglycemia,
dyslipidemia and
hypertension cluster in one individual. Intra-abdominal visceral fat accumulation plays a key role in the development of these disorders and the occurrence of
metabolic syndrome. We have investigated adipocyte functions intensively in the past 10 years and have revealed that these cells act as endocrine cells secreting a variety of 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 may contribute to the development of
vascular diseases.
Visfatin was identified recently 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, 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 1,
heparin-binding
epidermal growth factor-like
growth factor and
visfatin and hyposecretion of
adiponectin simultaneously, which results in the development of a variety of metabolic and circulatory diseases. In this article, the importance of
adipocytokines, focusing particularly on
adiponectin, is discussed with respect to lifestyle-related diseases, such as
diabetes mellitus and
cardiovascular disease.