Insulin resistance has been found to be the key pathophysiological factor of the metabolic syndrome and may precede the onset of impaired glucose tolerance, diabetes and dyslipidemia. Recently, nonalcoholic fatty liver disease (NAFLD), has been identified as another feature of this syndrome. Importantly, a close relation between liver fat content and hepatic insulin sensitivity has been described. We hypothesize that activation of FXR with chenodeoxycholic acid decreases hepatic de novo lipogenesis and subsequently hepatic fat content and triglyceride production. The decrease in liver fat content will be associated with improved hepatic insulin sensitivity and a decrease in hepatic glucose production.~Patients diagnosed with metabolic syndrome, familial hypertriglyceridemia or familial combined hyperlipidemia will be recruited from the the outpatients department of the Division of Endocrinology, Diabetology and Clinical Nutrition, University Hospital Basel. Eligible patients will be admitted to the CRC for metabolic studies, including baseline blood samples for the measurement of hormones, cytokines and adipokines, euglycemic-hyperinsulinemic clamp studies for the assessment of glucose turnover and insulin sensitivity and in vivo NMR studies to determine intrahepatic and intramyocellular lipid content. Patients will alternatively receive chenodeoxycholic acid and placebo. The study population will be compared to a group of age, gender and weight matched normolipidemic controls.
The purpose of this study is to determine whether chenodeoxycholic acid decreases de novo hepatic lipogenesis, hepatic fat content, hepatic triglyceride production and plasma triglyceride concentrations and improves hepatic glucose metabolism in patients with the metabolic syndrome, Familial Hypertriglyceridemia and Familial Combined Hyperlipidemia.