Insulin resistance and NAFLD: Relationship with intrahepatic iron and serum TNF-α using 1H MR spectroscopy and MRI

Aim. - The association of non-alcoholic fatty liver disease (NAFLD) with insulin resistance (IR) is well established, yet little is known of their possible relationship with intrahepatic iron and serum tumour necrosis factor (TNF)-alpha concentrations in adults without diabetes. Thus, this study looked at the relationship of intrahepatic iron and serum TNF-alpha with intrahepatic triglycerides and IR in non-diabetic adults. Methods. - In this cross-sectional study of 104 healthy non-diabetic Caucasians, a quantitative magnetic resonance (MR) imaging T2 gradient-echo technique was used to measure hepatic iron, with 1H-MR spectroscopy used to measure hepatic triglycerides. HOMA-IR was calculated to determine IR. Results. - The prevalence of hepatic iron overload (HIOL) was 26.6% in individuals with NAFLD vs. 0% in those without. IR was present in 87.5% of subjects with both NAFLD and HIOL, in 45.4% of those with NAFLD but not HIOL, and in 4.5% of those with neither. HOMA-IR was positively correlated with hepatic triglycerides (r = 0.56, P < 0.001) and hepatic iron (r = 0.52, P < 0.001), whereas serum TNF-alpha concentrations correlated with intrahepatic triglyceride levels (r = 0.28, P < 0.04), but not with intrahepatic iron. Hepatic triglycerides, serum TNF-alpha and age were the only significant determinants of IR in regression analyses. Conclusion. - IR is closely associated with intrahepatic triglycerides and, to a lesser extent, intrahepatic iron, with some interplay between them. High serum TNF-alpha concentrations may contribute to the association between NAFLD and IR, while increased hepatic triglycerides appear to be a determinant of the development of HIOL in non-diabetic subjects without haemochromatosis. (C) 2019 Elsevier Masson SAS. All rights reserved.