Effects of exenatide, insulin, and pioglitazone on liver fat content and body fat distributions in drug-naive subjects with type 2 diabetes

Ectopic accumulation of lipids in nonadipose tissues plays a primary role in the pathogenesis of type 2 diabetes mellitus (T2DM). This study was to examine the effects of exenatide, insulin, and pioglitazone on liver fat content and body fat distributions in T2DM. Thirty-three drug-naive T2DM patients (age 52.7 ± 1.7 years, HbA1c 8.7 ± 0.2 %, body mass index 24.5 ± 0.5 kg/m²) were randomized into exenatide, insulin, or pioglitazone for 6 months. Intrahepatic fat (IHF), visceral fat (VF), and subcutaneous fat (SF) were measured using proton nuclear magnetic resonance spectroscopy. Plasma tumor necrosis factor α (TNFα) and adiponectin were assayed by ELISA. HbA1c declined significantly in all three groups. Body weight, waist, and serum triglycerides decreased with exenatide. After interventions, IHF significantly reduced with three treatments (exenatide Δ = −68 %, insulin Δ = −58 %, pioglitazone Δ = −49 %). Exenatide reduced VF (Δ = −36 %) and SF (Δ = −13 %), and pioglitazone decreased VF (Δ = −30 %) with no impact on SF, whereas insulin had no impact on VF or SF. Levels of TNFα (exenatide/insulin/pioglitazone) decreased, and levels of adiponectin (exenatide/pioglitazone) increased. Analysis showed that ΔIHF correlated with ΔHbA1c and Δweight. Besides, ΔIHF correlated with Δtriglycerides and ΔTNFα, but the correlations fell short of significance after BMI adjustment. By linear regression analysis, ΔHbA1c alone explained 41.5 % of the variance of ΔIHF, and ΔHbA1c + Δweight explained 57.6 % of the variance. Liver fat content can be significantly reduced irrespective of using exenatide, insulin, and pioglitazone. Early glycaemic control plays an important role in slowing progression of fatty liver in T2DM.