肥満発症と動脈硬化

抄録

We clarified, using computed tomography, that the accumulation of intra-abdominal visceral fat is more closely associated with complications of obesity, such as diabetes mellitus, hyperlipidemia, hypertension and ischemic heart disease, than the accumulation of subcutaneous fat. Recently we also revealed that the accumulation of intra-abdominal visceral fat correlates to metabolic disorders and cardiovascular disease even in normal weight subjects. From these backgrounds, we proposed the concept of “visceral fat syndrome”, a multiple risk factors-clustering syndrome for the incidence of atherosclerosis. Clinically, it was showed that the reduction of visceral fat should be important for the cure and the protection of these disorders. We have suggested that physical exercise reduced accumulated visceral fat prominently from the observations of the effect of exercise therapy on visceral fat type obesity and the analysis of fat distribution of sumo wrestlers. In order to clarify the effect of exercise on fat distribution, the mRNA levels and the activities of acyl-CoA synthetase (ACS), lipoprotein lipase (LPL), and glucose transporter (Glut 4) in some tissues were compared between exercised and sedentary rats. We observed rapid decrease of tissue weight in visceral fat through marked decrease of ACS, LPL, and Glut 4 parameters, while there were no alterations of them in subcutaneous fat. Gastrocnemius muscle was heavier in exercised rats, and ACS activity elevated in the gastrocnemius muscle of the exercised rats. By analyzing the expressed genes in human visceral fat, compared with human subcutaneous fat and various tissues, visceral fat was showed to have a higher metabolic activity at fene expression level. We suggest that intra-abdominal visceral fat may contribute to switching of distribution of plasma energy flux, including lipid and glucose, from fat tissue to muscle in physical exercise, in rapid response to exercise from transcriptional level.