Pathophysiology and pathogenesis and visceral fat obesity

Abstract

MATSUZAWA, YUJI, IICHIRO SHIMOMURA, TADASHI NAKAMURA, YOSHIAKI KENO, KASUAKI KOTANI, KATSUTO TOKUNAGA. Pathophysiology and pathogenesis of visceral fat obesity. Obes Res. 1995;3 (suppl2):187~-194s. Based on the analysis of fat distribution by computed tomography (CT) scans, the classification scheme for obesity should include visceral fat obesity in which fat accumulationis predominant in the intra-abdominalcavity. Obese subjectsivith visceral fat accumulation more frequently demonstrateimpairment of glucose andlipid metabolism than those withsubcutaneous fat accumulation. Wehaveshownthatvisceralfat obesity is present in almost90% ofobesepatientswithischemicheart disease. Even in non-obese subj ects, visceral fat accumulation is correlatedwith glucose intolerance, hyperlipidemia and hypertension. Forty percent of non-obese subjects with coronary artery disease (CAD) had increased visceral fat. In non-obese subjects, visceral fat area assessed by abdominal CT at the level of the umbilicus correlates with metabolic risk factors, whereas in obese subjects the visceralfat area to subcutaneous fat area ratio provides a more significant correlation. From clinical and basic investigations, aging, sex hormones, excess intake of sucrose and lackof physical exercise have been suggested to be determinants for visceral fat accumulation. Since intra-abdominal fat (mesenteric andomentum fat) has beenshown to havehigh activities of bothlipogenesis and lipolysis,its accumulation can induce high levels offree fatty acids, a product of lipolysis, in portal circulation which go into the liver. Excess free fatty acids may cause the enhancement of lipid synthesis and gluconeogenesis as well as insulin resistance, resulting in hyperlipidemia, glucose intolerance and hypertension and finally atherosclerosis. From The Second D e p m c n t of Internal M d c m c , Osaka UNVCIX~~ Med~cal School. 2-2, Yamadaoka S u b , Osaka 565, Japan. Repnnt requests to Dr. Matsuzawa. The Second Department of Internal Medicine. Osaka University Medical School. 2-2. Yamadaoka Suita, Osaka 565. Japan. Copynght 01995 NAASO. Thus we propose a disease entity, visceral fat syndrome,whichmay increase susceptibility to atherosclerosis due to multiple risk factors induced by visceral fat accumulation.