Recently, the number of diabetic patients has been increasing in Japan and is currently about 740 million. Metabolic syndrome starts with obesity, especially visceral adiposity, and accelerates atherosclerosis in association with diabetes, hyperlipidemia and hypertension, leading to increased risk of developing myocardial infarction and stroke. This program aims to develop innovative diagnostic/therapeutic methods, based on molecular mechanisms underlying the development of diabetes and atherosclerosis.

• Project for Metabolic Syndrome
  

  Lifestyle-related diseases like diabetes and metabolic syndrome develop with various genetic predispositions, combined with environmental factors. For example, the sharp increase in the number of diabetes patients in Japan is assumed to be due to lower insulin secretory capacity of pancreatic beta cells in Japanese as compared to Westerners (genetic predisposition), and the fact that pancreatic beta cells do not fully compensate for insulin-resistant conditions like westernized high-fat diets and reduced physical activity (environmental factors). This project involves research on the interaction of genetic and environmental factors in lifestyle-related diseases (e.g. metabolic syndrome, obesity, diabetes), aimed at exploring the causes and pathophysiology of these diseases.

  
  

• Project for Nutritional Therapy
  

  Excess energy intake, especially increased fat intake, is one of the major causes of diabetes and obesity. However, physiological free fatty acid concentrations are essential for insulin secretion, which would increase, in the short term, the secretion of glucose-responsive insulin. On the other hand, prolonged excess fat intake results in triglyceride accumulation in pancreatic beta cells, leading to decreased insulin secretion. It has been reported that fat intake contributes to obesity more than carbohydrate and protein intakes. Individuals with higher fat intakes are, therefore, more prone to obesity than those with lower fat intakes, even if total energy intakes are the same. In this project, we examine the impacts of diets with different nutrient compositions on insulin secretion, glucose tolerance, insulin resistance, and obesity in genetically modified diabetes-, insulin resistant- and obesity-model animals. In this way, our project aims to identify novel clinical applications by developing the optimal nutritional therapy, in terms of nutrient-to-energy ratio, for preventing lifestyle-related diseases.