Comparative proteomics reveals different protein expression in platelets in patients with alcoholic liver cirrhosis.

Background: The role of platelets in disease progression as well as the function of platelets as part of the haemostatic and immunological system in patients with liver cirrhosis is only incompletely understood. This is partly due to difficulties in assessing platelet function. Proteome analyses of platelets have been used to further investigate the role of platelets in other diseases.

Aim: To assess possible changes in the platelet proteome during different stages of alcohol induced liver cirrhosis compared to healthy donors.

Patients and methods: A 45 ml blood sample was drawn from 18 participants aged 18-80 years evenly divided into three groups of healthy donors, patients with less advanced alcohol induced liver cirrhosis (Child-Pugh < 7) and patients with advanced liver cirrhosis (Child-Pugh > 10). The blood was processed to isolate platelets and perform subsequent two-dimensional gel-electrophoresis using a SYPRO™ Ruby dye. After computational analysation significantly in- or decreased protein spots (defined as a two-fold abundance change between different study cohorts and ANOVA < 0.05) were identified via liquid chromatography-mass spectrometry (LCMS) and searching against human protein databases.

Results: The comparative analysis identified four platelet proteins with progressively decreased protein expression in patients with liver cirrhosis. More specifically Ras-related protein Rab-7a (Rab-7a), Ran-specific binding protein 1 (RANBP1), Rho GDP-dissociation inhibitor 1 (RhoGDI1), and 14-3-3 gamma.

Conclusion: There is significant change in protein expression in the platelet proteome throughout the disease progression of alcohol induced liver cirrhosis. The identified proteins are possibly involved in haemostatic and immunoregulatory function of platelets.