Plasma-targeted proteomic and lipidomic profiling of MASLD, MASH, and hepatitis C virus infection

Metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH) are chronic liver diseases characterized by lipid accumulation and persistent inflammation, often progressing to fibrosis or hepatocellular carcinoma (HCC). Hepatitis C virus (HCV) infection shares overlapping pathological features, including chronic inflammation and fibrogenesis. Despite their prevalence, reproducible plasma-level molecular data that capture disease-associated systemic alterations remain limited.

We conducted targeted proteomic and targeted lipidomic profiling of several hundred plasma samples from Japanese patients diagnosed with MASLD, MASH, or HCV infection. Targeted proteomics quantified 184 plasma proteins using the Olink Proximity Extension Assay, and targeted lipidomics quantified approximately 500 phospholipid and triglyceride species using LC/MS-based selected reaction monitoring. Reproducibility was assessed across three independent cohorts.

Seven proteins (CASP-8, CCL20, CTSD, SCF, MMP-3, TRAIL, and TWEAK) consistently differed between MASLD and MASH across all cohorts, reflecting coordinated changes related to apoptosis, inflammation, and immune signaling. Similar alterations were observed in HCV (Hepatitis C virus), indicating shared immune dysregulation. Lipidomic analysis revealed reproducible remodeling characterized by decreased ether-linked phosphatidylethanolamine (PE), increased ester-linked PE, and elevated saturated sphingomyelin (SM) in MASH. Correlation analyses indicate coordinated relationships between selected protein and lipid alterations, including relationships between CTSD and PE and triglyceride (TG) species containing linoleic acid (18:2).

The results of this research provide value to the field of proteomics as a large-scale, reproducible, and hypothesis-generating plasma dual-omics reference dataset. This study was not designed to establish diagnostic biomarkers, to assess clinical discriminative performance, or to imply causal mechanisms. Instead, by emphasizing reproducibility independent cohorts, we provide a plasma dual-omics reference dataset that captures coordinated immune and lipid metabolic alterations associated with chronic liver disease severity. These data provide a framework and resource for future studies researching risk stratification, therapeutic monitoring, and mechanistic validation in chronic liver disease.