Fecal Proteomics Suggest Potential Biomarkers for Non-Alcoholic Fatty Liver Disease and Steatohepatitis

Non-alcoholic Fatty Liver Disease (NAFLD) affects about a quarter of the world's population. Liver biopsy remains the gold standard for diagnosing the progressive form of NAFLD called Non-alcoholic Steatohepatitis (NASH) but it is invasive, prone to sampling errors and observer variability, and impractical for widespread use. Fecal non-invasive biomarkers have emerged as a new approach to diagnose, stage, and monitor NAFLD over time.

Proteomic analysis was performed using Liquid Chromatography-Mass Spectrometry (LC-MS/MS) in fecal samples derived from mice fed with high fat and sugar diet representing NAFLD model and with the addition of 5 cycles of dextran-sulphate in drinking water to induce a NASH.

Qualitative and quantitative different protein profiles resulted in a comparison between the three groups of mice. An enrichment analysis of differentially expressed proteins explores the molecular pathways involved. A selection of the most significant modulated proteins between groups was performed. The proteins Transthyretin, Kallikrein1 and Trefoil Factor 3 were validated by ELISA.

Our exploratory discovery study identified several proteins that, alone or in combination, enable a good separation between NASH, NAFLD and healthy mice, highlighting their potential as key targets for future research.