Histological Assessment of NASH Liver Samples

Human paraffin-embedded liver tissues were obtained from the Department of Pathology at Peking University People’s Hospital. In this study, 6 liver tissue samples from biopsy-proven NASH patients with fibrosis and 3 samples from healthy donors (age ≥18 years) were eligible and included. Patients with viral hepatitis, alcoholic liver disease, drug-induced liver disease, autoimmune liver disease, cholestatic liver disease or hereditary metabolic liver disease were not ineligible. We did not assess whether subjects were male or female because sex was not the analysis object in this study. We did not check for sample sizes using a power analysis because our study does not report statistics on between groups or within group variables. Informed consent forms were obtained from all participants. This study was approved by the Ethics Committee of Peking University People’s Hospital (2022PHB088-001) and conformed to the ethical guidelines of the 1975 Declaration of Helsinki.
Each sample (human and mouse) was sectioned at a thickness of 4 μm for histological assessment and immunohistochemistry (IHC). Using hematoxylin and eosin (H&E) and Sirius Red (SR) staining, liver histology for all participants was evaluated by two specialized pathologists who were blinded to the patient and mouse details according to the NASH Clinical Research Network (NASH CRN) System (steatosis was scored from 0-3, ballooning: 0-2, lobular inflammation: 0-3, portal inflammation: 0-2, and liver fibrosis: 0 to 4).