Plasma biomarker screening for liver fibrosis with the N-terminal isotope tagging strategy

A non-invasive diagnostic approach is crucial for the evaluation of severity of liver disease, treatment decisions, and assessing drug efficacy. This study evaluated plasma proteomic profiling via an N-terminal isotope tagging strategy coupled with liquid chromatography/Fourier transform ion cyclotron resonance mass spectrometry measurement to detect liver fibrosis staging. Pooled plasma from different liver fibrosis stages, which were assessed in advance by the current gold-standard of liver biopsy, was quantitatively analyzed. A total of 72 plasma proteins were found to be dysregulated during the fibrogenesis process, and this finding constituted a valuable candidate plasma biomarker bank for follow-up analysis. Validation results of fibronectin by Western blotting reconfirmed the mass-based data. Ingenuity Pathways Analysis showed four types of metabolic networks for the functional effect of liver fibrosis disease in chronic hepatitis B patients. Consequently, quantitative proteomics via the N-terminal acetyl isotope labeling technique provides an effective and useful tool for screening plasma candidate biomarkers for liver fibrosis. We quantitatively monitored the fibrogenesis process in CHB patients. We discovered many new valuable candidate biomarkers for the diagnosis of liver fibrosis and also partly identified the mechanism involved in liver fibrosis disease. These results provide a clearer understanding of liver fibrosis pathophysiology and will also hopefully lead to improvement of clinical diagnosis and treatment. ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material is available for this article at 10.1007/s11427-011-4165-y and is accessible for authorized users.