• Johannie du Plessis, Jos van Pelt, Hannelie Korf, Chantal Mathieu, Bart van der Schueren, Matthias Lannoo, Tom Oyen, Baki Topal, Gary Fetter, Simon Nayler, Tessa van der Merwe, Petra Windmolders, Luc Van Gaal, An Verrijken, Guy Hubens, Martin Gericke, David Cassiman, Sven Francque, Frederik Nevens, and Schalk van der Merwe.
• Laboratory of Hepatology, Faculty of Medicine, University of Leuven, Leuven, Belgium; Department of Immunology, Hepatology and GI Research Laboratory, University of Pretoria, Pretoria, South Africa.
• Gastroenterology. 2015 Sep 1; 149 (3): 635-48.e14.

Background & AimsThe prevalence of nonalcoholic fatty liver disease (NAFLD) has increased with the obesity pandemic. We analyzed the transcriptional profiles of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT), and phenotypes and functional characteristics of adipocyte tissue macrophages (ATMs), in obese patients undergoing bariatric surgery.MethodsWe collected anthropometric data; plasma samples; and SAT, VAT, and liver tissues from 113 obese patients undergoing bariatric surgery at academic hospitals in Europe (Antwerp and Leuven) and South Africa. Based on clinical and histologic features, patients were assigned to the following groups: obese, NAFLD, nonalcoholic steatohepatitis (NASH), or NASH with fibrosis. Microarray analyses were performed to identify genes expressed differentially among groups. We measured levels of cytokines and chemokines in plasma samples and levels of RNAs in adipose tissues by quantitative reverse-transcription polymerase chain reaction. ATMs were isolated from patients and 13 lean individuals undergoing cholecystectomy (controls), analyzed by flow cytometry, and cultured; immunophenotypes and levels of cytokines and chemokines in supernatants were determined.ResultsWe observed increased expression of genes that regulate inflammation in adipose tissues from patients with NAFLD and NASH; expression of these genes increased as disease progressed from NAFLD to NASH. We found 111 genes associated with inflammation that were expressed differentially between VAT and SAT. Serum levels of interleukin 8, chemokine (C-C motif) ligand 3, and tumor necrosis factor-α correlated with liver inflammation and NAFLD activity score. We developed 2 models that could be used to determine patients' liver histology based on gene expression in VAT and SAT. Flow cytometry showed increased proportions of CD11c+CD206+ and CCR2+ macrophages in VAT from patients with NASH, and supernatants of cultured macrophages had increased levels of cytokines and chemokines compared with controls.ConclusionsVAT and SAT from patients with NAFLD and NASH have an increased expression of genes that regulate inflammation, and ATM produce increased levels of inflammatory cytokines, compared with adipose tissues from controls. We identified an expression profile of 5 genes in SAT that accurately predict liver histology in these patients. Transcript profiling: accession numbers: GSE58979 and GSE59045.Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.

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