title: Integrated metabonomic analysis of bromobenzene-induced hepatotoxicity: novel induction of 5-oxoprolinosis.
abstract: We present here a definitive metabonomic analysis in order to detect novel biomarker and metabolite information, implicating specific putative protein targets in the toxicological mechanism of bromobenzene-induced centrilobular hepatic necrosis. Male Han-Wistar rats were dosed with bromobenzene (1.5 g/kg, n = 25) and blood plasma, urine and liver samples were collected for NMR and magic angle spinning (MAS) NMR spectroscopy at various time-points postdose, with histopathology and clinical pathology performed in parallel. Liver samples were analyzed by 600 MHz 1H MAS NMR techniques and the resultant spectra were correlated to sequential 1H NMR measurements in urine and blood plasma using pattern recognition methods. 1D 1H NMR spectra were data-reduced and analyzed using principal components analysis (PCA) to show the time-dependent biochemical variations induced by bromobenzene toxicity. In addition to a holistic view of the effect of hepatic toxicity on the metabolome, a number of putative protein targets of bromobenzene and its metabolites were identified including those enzymes of the glutathione cycle, exemplified by the presence of a novel biomarker, 5-oxoproline, in liver tissue, blood plasma, and urine. As such, this work establishes the importance of metabonomics technology in resolving the mechanistic complexity of drug toxicity as well as the benefits of frontloading this approach in drug safety evaluation and biomarker discovery.
authors.affiliation: Biological Chemistry, Division of Biomedical Sciences, Sir Alexander Fleming Building, Imperial College, London, SW7 2AZ, United Kingdom. nigel.waters@astrazeneca.com
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Waters
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Waterfield
authors.forename: R Duncan
authors.initials: RD
authors.lastname: Farrant
authors.forename: Elaine
authors.initials: E
authors.lastname: Holmes
authors.forename: Jeremy K
authors.initials: JK
authors.lastname: Nicholson
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001798:Blood Proteins / Q000032:analysis*; D001969:Bromobenzenes / Q000633:toxicity*; D056486:Chemical and Drug Induced Liver Injury / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009336:Necrosis; D011761:Pyrrolidonecarboxylic Acid / Q000097:blood / Q000378:metabolism* / Q000652:urine; D051381:Rats
chemical_list: D015415:Biomarkers; D001798:Blood Proteins; D001969:Bromobenzenes; C032036:bromobenzene; D011761:Pyrrolidonecarboxylic Acid