Dataset Information

Hepatocyte Hypoxia Inducible Factor-1 Mediates the Development of Liver Fibrosis in a Mouse Model of Nonalcoholic Fatty Liver Disease.

ABSTRACT:

Background

Obstructive sleep apnea (OSA) is associated with the progression of non-alcoholic fatty liver disease (NAFLD) to steatohepatitis and fibrosis. This progression correlates with the severity of OSA-associated hypoxia. In mice with diet induced obesity, hepatic steatosis leads to liver tissue hypoxia, which worsens with exposure to intermittent hypoxia. Emerging data has implicated hepatocyte cell signaling as an important factor in hepatic fibrogenesis. We hypothesized that hepatocyte specific knockout of the oxygen sensing ? subunit of hypoxia inducible factor-1 (HIF-1), a master regulator of the global response to hypoxia, may be protective against the development of liver fibrosis.

Methods

Wild-type mice and mice with hepatocyte-specific HIF-1? knockout (Hif1a-/-hep) were fed a high trans-fat diet for six months, as a model of NAFLD. Hepatic fibrosis was evaluated by Sirius red stain and hydroxyproline assay. Liver enzymes, fasting insulin, and hepatic triglyceride content were also assessed. Hepatocytes were isolated from Hif1a-/-hep mice and wild-type controls and were exposed to sustained hypoxia (1% O2) or normoxia (16% O2) for 24 hours. The culture media was used to reconstitute type I collagen and the resulting matrices were examined for collagen cross-linking.

Results

Wild-type mice on a high trans-fat diet had 80% more hepatic collagen than Hif1a-/-hep mice (2.21 ?g collagen/mg liver tissue, versus 1.23 ?g collagen/mg liver tissue, p = 0.03), which was confirmed by Sirius red staining. Body weight, liver weight, mean hepatic triglyceride content, and fasting insulin were similar between groups. Culture media from wild-type mouse hepatocytes exposed to hypoxia allowed for avid collagen cross-linking, but very little cross-linking was seen when hepatocytes were exposed to normoxia, or when hepatocytes from Hif1a-/-hep mice were used in hypoxia or normoxia.

Conclusions

Hepatocyte HIF-1 mediates an increase in liver fibrosis in a mouse model of NAFLD, perhaps due to liver tissue hypoxia in hepatic steatosis. HIF-1 is necessary for collagen cross-linking in an in vitro model of fibrosis.

SUBMITTER: Mesarwi OA

PROVIDER: S-EPMC5193414 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Publications

Hepatocyte Hypoxia Inducible Factor-1 Mediates the Development of Liver Fibrosis in a Mouse Model of Nonalcoholic Fatty Liver Disease.

Mesarwi Omar A OA Shin Mi-Kyung MK Bevans-Fonti Shannon S Schlesinger Christina C Shaw Janet J Polotsky Vsevolod Y VY

PloS one 20161228 12

<h4>Background</h4>Obstructive sleep apnea (OSA) is associated with the progression of non-alcoholic fatty liver disease (NAFLD) to steatohepatitis and fibrosis. This progression correlates with the severity of OSA-associated hypoxia. In mice with diet induced obesity, hepatic steatosis leads to liver tissue hypoxia, which worsens with exposure to intermittent hypoxia. Emerging data has implicated hepatocyte cell signaling as an important factor in hepatic fibrogenesis. We hypothesized that hepa ...[more]

PMID: 28030556

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Project description:ImportanceThe diagnostic performance of the fibrosis-4 index (FIB-4) and nonalcoholic fatty liver disease (NAFLD) fibrosis score (NFS) for advanced fibrosis in lean patients with NAFLD is limited.ObjectiveTo evaluate the diagnostic performance of the FIB-4 and NFS in lean individuals with NAFLD.Design, setting, and participantsThis diagnostic study included adults with biopsy-proven NAFLD from 6 referral centers in Asia from 1995 to 2019. Cohorts were matched by age and sex between the lean and nonlean groups. All statistical analyses were executed from October 2022 to March 2023.Main outcomes and measuresThe diagnostic performance of the FIB-4 and NFS at the current cutoff for advanced hepatic fibrosis in lean (body mass index [BMI] below 23 [calculated as weight in kilograms divided by height in meters squared]) and nonlean (BMI above 23) patients were evaluated.ResultsA total of 1501 patients were included in analysis (mean [SD] age, 46.1 [16.4] years); 788 male (52.5%), 115 lean (7.7%), 472 (30.2%) Korean, 821 (48.7%) Japanese, and 341 (21.3%) Taiwanese. Among the age- and sex-matched cohort, the mean (SD) age was 52.3 (15.1) years and 41.2% (47 of 114) were male. The diagnostic performance and areas under the operating characteristic curve of the FIB-4 (lean, 0.807 vs nonlean, 0.743; P = .28) and NFS (lean, 0.790 vs nonlean, 0.755; P = .54) between the 2 groups were comparable in the age- and sex-matched cohort. The sensitivity and specificity of the NFS showed increasing and decreasing tendency according to the BMI quartiles (P for trend < .001), while those of the FIB-4 did not (P for trend = .05 and P = .20, respectively). Additionally, although the areas under the operating characteristic curve of the FIB-4 and NFS were not significantly different in the lean group (0.807 vs 0.790; P = .09), the sensitivity of the current NFS cutoff values was lower in the lean group than in that of FIB-4 (54.4% vs 81.8%; P = .03).Conclusions and relevanceIn this cohort study, the performance of the FIB-4 and NFS in diagnosing advanced fibrosis did not differ significantly between the 2 groups overall. However, in lean NAFLD, while the sensitivity for diagnosing advanced hepatic fibrosis remained reasonable at the current cutoff level, the sensitivity of NFS at the current cutoff was too low to be an adequate screening tool.

Dataset Information

Hepatocyte Hypoxia Inducible Factor-1 Mediates the Development of Liver Fibrosis in a Mouse Model of Nonalcoholic Fatty Liver Disease.

Background

Methods

Results

Conclusions

Publications

Hepatocyte Hypoxia Inducible Factor-1 Mediates the Development of Liver Fibrosis in a Mouse Model of Nonalcoholic Fatty Liver Disease.

Similar Datasets

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