Biomarkers of Furan Exposure by Metabolic Profiling of Rat Urine with Liquid Chromatography-Tandem Mass Spectrometry and Principal Component Analysis

Abstract

Furan has been found in a number of heated food items and is carcinogenic in the liver of rats and mice. Estimates of human exposure on the basis of concentrations measured in food are not reliable because of the volatility of furan. A biomarker approach is therefore indicated. We searched for metabolites excreted in the urine of male Fischer 344 rats treated by oral gavage with 40 mg of furan per kg of body weight. A control group received the vehicle oil only. Urine collected over two 24-h periods both before and after treatment was analyzed by a column-switching LC-MS/MS method. Data were acquired by a full scan survey scan in combination with information dependent acquisition of fragmentation spectra by the use of a linear ion trap. Areas of 449 peaks were extracted from the chromatograms and used for principal component analysis (PCA). The first principal component fully separated the samples of treated rats from the controls in the first post-treatment sampling period. Thirteen potential biomarkers selected from the corresponding loadings plot were reanalyzed using specific transitions in the MRM mode. Seven peaks that increased significantly upon treatment were further investigated as biomarkers of exposure. MS/MS information indicated conjugation with glutathione on the basis of the characteristic neutral loss of 129 for mercapturates. Adducts with the side chain amino group of lysine were characterized by a neutral loss of 171 for N-acetyl- l-lysine. Analysis of products of in vitro incubations of the reactive furan metabolite cis-2-butene-1,4-dial with the respective amino acid derivatives supported five structures, including a new 3-methylthio-pyrrole metabolite probably formed by beta-lyase reaction on a glutathione conjugate, followed by methylation of the thiol group. Our results demonstrate the potential of comprehensive mass spectrometric analysis of urine combined with multivariate analyses for metabolic profiling in search of biomarkers of exposure.

Trapping of cis-2-Butene-1,4-dial to Measure Furan Metabolism in Human Liver Microsomes by Cytochrome P450 Enzymes

“…NAC-BDA-NAL is a significant metabolite detected in the urine of furan-treated rats (Kellert et al, 2008b;Lu et al, 2009). Data support the hypothesis that this compound is a downstream metabolite of degraded furan-derived protein adducts (Lu et al, 2009;Hamberger et al, 2010).…”

“…BDA is genotoxic (Marinari et al, 1984;Peterson et al, 2000;Kellert et al, 2008a) and forms adducts with various cellular nucleophiles such as DNA, protein, and polyamines (Chen et al, 1997;Gingipalli and Dedon, 2001;Byrns et al, 2002Byrns et al, , 2004Lu et al, 2009;Peterson et al, 2011), which is evidence that BDA may be responsible for furan-induced toxicities. Conjugates of BDA have been detected in the urine and bile of furan-treated rats (Peterson et al, 2006(Peterson et al, , 2011Kellert et al, 2008b;Lu et al, 2009;Hamberger et al, 2010;Lu and Peterson, 2010).…”

A foresight study on emerging technologies: State of the art of Omics technologies and potential applications in food and feed safety

“…A metabolomics study primarily aimed at investigation of a dose-response relationship, Mally et al (2010), established dominantly negative results in terms of metabolic changes in urine although there were some changes in serum concentrations of bile acids at the highest doses A metabolic profiling study, Kellert et al (2008), identified unknown furan metabolites but did not establish strong evidence for biomarker identification…”

“…Kellert et al (2008) describe an explicit metabolomics search for biomarkers of furan exposure in the urine of treated rats. Principle components analysis is used to identify a small number of potential markers from an initial screening involving approximately 450 metabolites (including unknown species).…”

Metabonomics Study of Brain-Specific Human S100B Transgenic Mice by Using High-Performance Liquid Chromatography Coupled with Quadrupole Time of Flight Mass Spectrometry

“…[5][6][7][8] Metabonomics study was divided into four levels, including target analysis, profiling analysis, fingerprint analysis and metabonomics analysis. In this paper, metabonomics study based on the HPLC/MS-ESI-TOF analysis was applied to understanding the metabolic profiling of S100B transgenic mice and identifying the potential biomarkers relating to S100B protein.…”