Distinct Hepatic Gene-Expression Patterns of NAFLD in Patients With Obesity

Area of Science:

• Hepatology
• Molecular Biology
• Genomics

Background:

• Nonalcoholic fatty liver disease (NAFLD) management is hindered by incomplete understanding of its pathogenesis.
• Obesity is a major risk factor for NAFLD development and progression.

Purpose of the Study:

• To identify hepatic gene-expression patterns associated with different NAFLD phenotypes in adults with obesity.
• To elucidate the molecular mechanisms underlying NAFLD progression.

Main Methods:

• Quantification of 795 genes involved in fibrosis, inflammation, and steatosis using NanoString nCounter assay in liver tissue from 318 adults with obesity.
• Categorization of liver specimens into four NAFLD phenotypes: normal liver histology (NLH), steatosis only, nonalcoholic steatohepatitis without fibrosis (NASH F0), and NASH with fibrosis (NASH F1-F4).

Main Results:

• 125 genes showed significant changes with NAFLD progression.
• NASH F0 exhibited increased inflammatory genes (e.g., IFI30, CXCL9) and reduced complement/coagulation genes (e.g., C9, C4BPB) compared to NLH.
• NASH F1-F4 showed increased extracellular matrix degrading enzymes and profibrotic genes (e.g., collagens, TGFB1), indicating tissue remodeling.

Conclusions:

• Distinct NAFLD states in adults with obesity are linked to specific intrahepatic gene expression changes.
• These perturbations involve inflammation, complement and coagulation pathways, and tissue remodeling.
• The findings provide insights into the dynamic pathogenesis of NAFLD in high-risk individuals.