Domitille Schvartz1, Alessandro Aliotta1,3, Yvonne Gloor2, Jules Desmeules2, Caroline Samer2, Jean-Charles Sanchez1
1 Department of Human Protein Science, University of Geneva, Geneva, Switzerland
2 Department of Clinical Pharmacology and Toxicology, Geneva University Hospital, Geneva, Switzerland
3 School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
Objective: Paracetamol (APAP) is a world widely prescribed analgesic and antipyretic drug. Incorrectly dosed, it is the most common cause of acute liver failure (ALF) in developed countries. Even used at therapeutic dose (4g/day), up to one third of healthy volunteers as well as hospitalized patients display elevated liver tests after APAP intake in the presence of risk factors such as malnutrition, chronic alcohol intake, or co-medications. It is therefore crucial to very early detect and diagnose paracetamol-induced hepatotoxicity. Blood microparticles (MPs) are circulating microvesicles whose content is specific to their cell of origin, and reflect pathophysiological states. MPs are used here as potential plasma-derived biomarker holders of APAP-induced hepatotoxicity.
Methods: MPs were isolated from human whole blood by differential centrifugations, and pelleted from platelet-free plasma after centrifugation at 18.000g for 45 min. Quantitative proteomics strategies (10plex isobaric Tandem Mass Tag - TMT) were applied to compare the MV protein content from patients under APAP treatment that encountered liver test elevation (n=5), at 3 different time points. Additional tags were used as control (MV pools) and as reference (HepaRG cells). Quantitative analysis was performed with Proteome Discoverer (v2.2).
Results: A protocol for MP isolation was implemented and a proteome of blood-circulating MPs was depicted. We identified more than 430 (1% FDR, at least two distinct peptides), 90% were present in our MV protein list of reference, which confi¬rmed the MV enrichment. Twenty of these proteins are shown to be regulated in at least one time point of APAP patient (two-way ANOVA, adj.p-val (Tukey)<0.05), six proteins were selected for further validation. Namely, Serum amyloid A, Vitronectin, fibrinogen α, glutathione-S-transferase α1, CD9 antigen and SLC2A3 are currently undergoing ELISA verification on a larger number of patients.
Conclusion: The present study underlines MPs value for biomarker discovery in the context of APAP-induced hepatotoxicity. Moreover, the proteins found differentially expressed are consistent with the biological context, as they were already described to be associated with hepatotoxicity mechanisms. They therefore represent promising candidates for the discovery of APAP-induced hepatotoxicity biomarkers.
Dr. Schvartz is working in the Translational Biomarker Group headed by Pr. Jean-Charles Sanchez at the University of Geneva. The group has conducted studies over the years for the discovery of diagnostic and prognostic biomarkers of brain injuries using proteomic approaches on body fluids. She has applied many “omics” approaches to her own research projects, mainly on type 2 diabetes. She is also the chair of a worldwide initiative of the Human Proteome Organization, gathering researchers in the field of diabetes and proteomics. She is now involved in a project aimed at discovering early biomarkers of drug-induced liver injury (DILI) by quantitative “omics”.