Insulin resistance, postprandial GLP-1 and adaptive immunity are the main predictors of NAFLD in a homogeneous population at high cardiovascular risk

Background and aims: The role of the different factors associated with fatty liver is still poorly defined. We evaluated the relationships between liver fat content (LF) and metabolic, inflammatory and nutritional factors in a homogeneous cohort of individuals at high cardio-metabolic risk. Methods and results: In 70 individuals with high waist circumference and at least one more criterion for metabolic syndrome enrolled in a nutritional intervention study, LF was evaluated at baseline by hepatic/renal echo intensity ratio (H/R), together with dietary habits (7-day dietary record), insulin sensitivity and beta-cell function (fasting and OGTT-derived indices), fasting and postprandial plasma GLP-1 and lipoproteins, and plasma inflammatory markers. H/R correlated positively with fasting and OGTT plasma glucose and insulin concentrations, HOMA-IR and beta-cell function, and IL-4, IL-17, IFN-gamma, TNF-alpha, FGF and GCSF plasma concentrations (p < 0.05 for all), and negatively with insulin sensitivity (OGIS), dietary, polyphenols and fiber (p < 0.05 for all). By multiple stepwise regression analysis, the best predictors of H/R were OGIS (beta = -0.352 p = 0.001), postprandial GLP-1 (beta = -0.344; p = 0.001), HDL-cholesterol (beta = -0.323; p = 0.002) and IFN-gamma (beta = 0.205; p = 0.036). Conclusion: A comprehensive evaluation of factors associated with liver fat, in a homogeneous population at high cardio-metabolic risk, indicated a pathogenic combination of the same pathways underlying the atherosclerotic process, namely whole body insulin sensitivity and inflammation. The higher predictive value of postprandial variables suggests that liver fat is essentially a postprandial phenomenon, with a relevant role possibly played by GLP-1. (C) 2016 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.