Hyperlipidemia and Fat Absorption in Model Rats with Type 2 Diabetes Mellitus

Type 2 diabetes mellitus is frequently complicated by hyperlipidemia, which is closely related to the occurrence of atherosclerotic disorders. The small intestine, which absorbs dietary lipids, plays an important role in the regulation of the serum lipid concentrations. We confirmed morphological changes in small intestinal villi in the progression of diabetes mellitus and evaluated intestinal lipid absorption by the 13C-trioctanoin breath test in model rats with type 2 diabetes mellitus (OLETF rats). We measured the height of the intestinal villous epithelium and serially measured the expiratory 13CO2 concentration after the administration of 13C-trioctanoin in OLETF rats at the ages of 28, 36, and 44 weeks. The serum total cholesterol and triglyceride concentrations were significantly higher in the OLETF rats than in the control LETO rats. The height of the small intestinal villi was increased, indicating hyperplastic change. The 13CO2 concentration was significantly increased, suggesting hyperplasia of the small intestinal villi and enhancement of lipid absorption or increased total amount absorption. Excessive lipid absorption from the small intestine was suggested to be one of the causes of hyperlipidemia (particularly hypertriglyceridemia) complicating diabetes mellitus.