New proteomics approaches for discovering biomarkers: Searching for liver fibrosis markers in hepatitis c patients
Gangadharan B., Bapat M., Rossa J., Antrobus R., Chittenden D., Kampa B., Barnes E., Klenerman P., Dwek RA., Zitzmann N.
Two-dimensional gel electrophoresis (2-DE) is often used to separate plasma or serum proteins in an attempt to identify novel biomarkers. A major difficulty with this approach is due to high abundant plasma/serum proteins which limits the detection of low abundance features. To overcome this problem a novel proteomics approach was developed and used to identify new fibrosis biomarkers in patients with different stages of liver fibrosis. Plasma samples from healthy individuals and patients with hepatitis C virus (HCV) induced cirrhosis were analysed using 2-DE over a narrow pH 3-5.6 range, a range outside the pH of highly abundant albumin, transferrin and immunoglobulins. Novel markers identified by this approach were validated across all fibrosis stages by Western blotting. 44 candidate biomarkers were revealed of which 20 were novel. Western blot analysis with newly identified biomarkers showed a consistent change with increasing fibrosis stage and were promising when compared to the markers used in established fibrosis tests. This is the first time the pH 3−5.6 range has been used to separate plasma by 2-DE. This pH range is useful for discovering novel biomarkers in all diseases. The novel fibrosis markers identified by this new proteomics approach may help to assess hepatic fibrosis and eliminate the need for invasive liver biopsies.