Basic Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. Aug 27, 2019; 11(8): 619-637
Published online Aug 27, 2019. doi: 10.4254/wjh.v11.i8.619
Prolonged high-fat-diet feeding promotes non-alcoholic fatty liver disease and alters gut microbiota in mice
Kandy T Velázquez, Reilly T Enos, Jackie E Bader, Alexander T Sougiannis, Meredith S Carson, Ioulia Chatzistamou, James A Carson, Prakash S Nagarkatti, Mitzi Nagarkatti, E Angela Murphy
Kandy T Velázquez, Reilly T Enos, Jackie E Bader, Alexander T Sougiannis, Meredith S Carson, Ioulia Chatzistamou, James A Carson, Prakash S Nagarkatti, Mitzi Nagarkatti, E Angela Murphy, Department of Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC 29209, United States
James A Carson, College of Health Professions, University of Tennessee Health Sciences Center, Memphis, TN 38163, United States
Author contributions: Velázquez KT performed the majority of experiments and analyzed the data; Chatzistamou I performed histopathological analysis; Velázquez KT performed staining; Velázquez KT, Enos RT, Carson MS, and Sougiannis AT performed molecular investigations; Velázquez KT, Bader JE, Nagarkatti PS, Nagarkatti M and Murphy EA designed and coordinated the microbiome research; Velázquez KT, Enos RT, Carson JA and Murphy EA designed and coordinated the obesity and non-alcoholic fatty liver disease research; Velázquez KT, Enos RT, and Murphy EA wrote the paper; all authors were involved in editing the manuscript.
Supported by National Institute of Health, No. NCI-3R01CA121249-08S1, NCCIH-K99AT009206 and No. NCI-1R21CA191966.
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the Institutional Animal Care and Use Committee at the University of South Carolina.
Conflict-of-interest statement: The authors declare no conflicts of interest.
Data sharing statement: Data from this manuscript will be available upon request.
ARRIVE guidelines statement: The authors have read the ARRIVE guidelines, and the manuscript was prepared and revised according to the ARRIVE guidelines.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: E Angela Murphy, PhD, Associate Professor, Department of Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina, 6439 Garners Ferry Rd, Columbia, SC 29209, United States. angela.murphy@uscmed.sc.edu
Telephone: +1-803-2163414 Fax: +1-803-2163414
Received: March 7, 2019
Peer-review started: March 11, 2019
First decision: April 11, 2019
Revised: July 5, 2019
Accepted: July 16, 2019
Article in press: July 17, 2019
Published online: August 27, 2019
Abstract
BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has become an epidemic largely due to the worldwide increase in obesity. While lifestyle modifications and pharmacotherapies have been used to alleviate NAFLD, successful treatment options are limited. One of the main barriers to finding safe and effective drugs for long-term use in NAFLD is the fast initiation and progression of disease in the available preclinical models. Therefore, we are in need of preclinical models that (1) mimic the human manifestation of NAFLD and (2) have a longer progression time to allow for the design of superior treatments.

AIM

To characterize a model of prolonged high-fat diet (HFD) feeding for investigation of the long-term progression of NAFLD.

METHODS

In this study, we utilized prolonged HFD feeding to examine NAFLD features in C57BL/6 male mice. We fed mice with a HFD (60% fat, 20% protein, and 20% carbohydrate) for 80 wk to promote obesity (Old-HFD group, n = 18). A low-fat diet (LFD) (14% fat, 32% protein, and 54% carbohydrate) was administered for the same duration to age-matched mice (Old-LFD group, n = 15). An additional group of mice was maintained on the LFD (Young-LFD, n = 20) for a shorter duration (6 wk) to distinguish between age-dependent and age-independent effects. Liver, colon, adipose tissue, and feces were collected for histological and molecular assessments.

RESULTS

Prolonged HFD feeding led to obesity and insulin resistance. Histological analysis in the liver of HFD mice demonstrated steatosis, cell injury, portal and lobular inflammation and fibrosis. In addition, molecular analysis for markers of endoplasmic reticulum stress established that the liver tissue of HFD mice have increased phosphorylated Jnk and CHOP. Lastly, we evaluated the gut microbial composition of Old-LFD and Old-HFD. We observed that prolonged HFD feeding in mice increased the relative abundance of the Firmicutes phylum. At the genus level, we observed a significant increase in the abundance of Adercreutzia, Coprococcus, Dorea, and Ruminococcus and decreased relative abundance of Turicibacter and Anaeroplasma in HFD mice.

CONCLUSION

Overall, these data suggest that chronic HFD consumption in mice can mimic pathophysiological and some microbial events observed in NAFLD patients.

Keywords: High-fat diet, Obesity, Non-alcoholic fatty liver disease, Gut microbiome, Endoplasmic reticulum stress, Inflammation, Fibrosis

Core tip: This work describes how mice consuming a chronic high-fat diet can mimic the clinical characteristics of non-alcoholic fatty liver disease. We used histopathological, metabolic, and molecular approaches to establish that prolonged high-fat-diet feedings in mice may be used as a pre-clinical model to study long-term interventions involving steatosis, steatohepatitis, fibrosis, glucose disturbances, endoplasmic reticulum stress, and gut microbial dysbiosis.