Observational Study
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World J Clin Cases. May 6, 2022; 10(13): 4097-4109
Published online May 6, 2022. doi: 10.12998/wjcc.v10.i13.4097
Metabolic dysfunction is associated with steatosis but no other histologic features in nonalcoholic fatty liver disease
Yi-Ning Dai, Cheng-Fu Xu, Hong-Ying Pan, Hai-Jun Huang, Mei-Juan Chen, You-Ming Li, Chao-Hui Yu
Yi-Ning Dai, Cheng-Fu Xu, You-Ming Li, Chao-Hui Yu, Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China
Yi-Ning Dai, Hong-Ying Pan, Hai-Jun Huang, Mei-Juan Chen, Center for General Practice Medicine, Department of Infectious Diseases, Zhejiang Provincial People's Hospital (Affiliated People’s Hospital, Hangzhou Medical College), Hangzhou 310014, Zhejiang Province, China
Author contributions: Yu CH and Li YM contributed to the study design; Dai YN, Xu CF, and Chen MJ contributed to data collection; Huang HJ and Chen MJ analyzed the data; Dai YN drafted the manuscript; Xu CF and Yu CH contributed to critical comments on the manuscript; Pan HY contributed to the manuscript revision.
Supported by the National Natural Science Foundation of China, No. 81800507; the Public Welfare Project of the Science and Technology Agency, Zhejiang Province, No. LGF18H030010; and Medical and Health Research Project of Zhejiang Province, No. 2018KY256 and No. 2019KY294.
Institutional review board statement: This study was approved by the People’s Hospital of Hangzhou Medical College Institutional Review Board (No. 2021QT257).
Informed consent statement: All study participants provided informed written consent prior to liver biopsy.
Conflict-of-interest statement: The authors declare no conflict of interests for this article.
Data sharing statement: No additional data are available.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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: Chao-Hui Yu, MD, PhD, Chief Doctor, Professor, Department of Gastroenterology, The First Affiliated Hospital, Zhejiang University School of Medicine, No. 79 Qingchun Road, Hangzhou 310003, Zhejiang Province, China. zyyyych@zju.edu.cn
Received: July 26, 2021
Peer-review started: July 26, 2021
First decision: August 19, 2021
Revised: September 1, 2021
Accepted: March 16, 2022
Article in press: March 16, 2022
Published online: May 6, 2022
Processing time: 277 Days and 14 Hours
Abstract
BACKGROUND

Recently, nonalcoholic fatty liver disease (NAFLD) has been renamed metabolic-associated fatty liver disease (MAFLD). Based on the definition for MAFLD, a group of non-obese and metabolically healthy individuals with fatty liver are excluded from the newly proposed nomenclature.

AIM

To analyze the histologic features in the MAFLD and non-MAFLD subgroups of NAFLD.

METHODS

Eighty-three patients with biopsy-proven NAFLD were separated into MAFLD and non-MAFLD groups. The diagnosis of MAFLD was established as hepatic steatosis along with obesity/diabetes or evidence of metabolic dysfunction. The histologic features were compared according to different metabolic disorders and liver enzyme levels.

RESULTS

MAFLD individuals had a higher NAFLD activity score (P = 0.002) and higher severity of hepatic steatosis (42.6% Grade 1, 42.6% Grade 2, and 14.8% Grade 3 in MAFLD; 81.8% Grade 1, 13.6% Grade 2, and 4.5% Grade 3 in non-MAFLD; P = 0.007) than the non-MAFLD group. Lobular and portal inflammation, hepatic ballooning, fibrosis grade, and the presence of nonalcoholic steatohepatitis (NASH) and significant fibrosis were comparable between the two groups. The higher the liver enzyme levels, the more severe the grades of hepatic steatosis (75.0% Grade 1 and 25.0% Grade 2 in normal liver function; 56.6% Grade 1, 39.6% Grade 2, and 3.8% Grade 3 in increased liver enzyme levels; 27.8% Grade 1, 27.8% Grade 2, and 44.4% Grade 3 in liver injury; P < 0.001). Patients with liver injury (alanine aminotransferase > 3 × upper limit of normal) presented a higher severity of hepatocellular ballooning (P = 0.021). Moreover, the grade of steatosis correlated significantly with hepatocellular ballooning degree (r = 0.338, P = 0.002) and the presence of NASH (r = 0.466, P < 0.001).

CONCLUSION

Metabolic dysfunction is associated with hepatic steatosis but no other histologic features in NAFLD. Further research is needed to assess the dynamic histologic characteristics in NAFLD based on the presence or absence of metabolic disorders.

Keywords: Nonalcoholic fatty liver disease; Metabolic associated fatty liver disease; Liver histology; Hepatic steatosis; Fibrosis

Core Tip: Non-obese and metabolically healthy patients with fatty liver are excluded from the definition of metabolic-associated fatty liver disease (MAFLD), but their clinical course has seldom been demonstrated. We analysed a group of nonalcoholic fatty liver disease (NAFLD) subjects, and found that the MAFLD subgroup had a higher NAFLD activity score and higher severity of hepatic steatosis than the non-MAFLD subgroup. There was no difference in other histologic features, including lobular and portal inflammation, balloon degeneration, and fibrosis, between the MAFLD and non-MAFLD patients. The grade of steatosis correlated positively with the hepatocellular ballooning degree, and the presence of nonalcoholic steatohepatitis. We believe that our study can provide insight into the histologic features of various subsets of fatty liver disease.