Liver fat content and hepatic insulin sensitivity in overweight patients with type 1 diabetes

Abstract

Objectives: Patients with type 1 diabetes mellitus (T1DM) lack the portal/peripheral insulin gradient, which might diminish insulin stimulation of hepatic lipogenesis and protect against development of nonalcoholic fatty liver disease (NAFLD). We compared liver fat content and insulin sensitivity of hepatic glucose production and lipolysis between overweight T1DM patients and nondiabetic subjects. Materials and Methods: We compared 32 overweight adult T1DM patients and 32 nondiabetic subjects matched for age, body mass index (BMI), and gender. Liver fat content was measured using proton magnetic resonance spectroscopy (1H-MRS), body composition by magnetic resonance imaging, and insulin sensitivity using the euglycemic-hyperinsulinemic clamp technique (insulin 0.4 mU/kg·min combined with infusion of D-[3-3H]glucose). We also hypothesized that low liver fat might protect from obesity-associated increases in insulin requirements and, therefore, determined insulin requirements across BMI categories in 3164 T1DM patients. Results: Liver fat content was significantly lower in T1DM patients than in nondiabetic subjects (0.6% [25th-75th quartiles, 0.3%-1.1%] vs 9.0% [3.0%-18.0%]; P < .001) and the percent suppression of nonesterified fatty acids significantly higher (89.1% [78.6%-93.3%] vs 51.4% [36.5%-71.1%]; P < .001) in T1DM patients than in nondiabetic subjects. Insulin doses were similar across BMI categories. Conclusions: T1DM patients might be protected from steatosis and hepatic insulin resistance. Obesity may not increase insulin requirements in T1DM.