Simultaneous detection of the tetrachloroethylene metabolites S-(1,2,2-trichlorovinyl) glutathione, S-(1,2,2-trichlorovinyl)-L-cysteine, and N-acetyl-S-(1,2,2-trichlorovinyl)-L-cysteine in multiple mouse tissues via ultra-high performance liquid chromatography electrospray ionization tandem mass spectrometry

Abstract

Tetrachloroethylene (perchloroethylene; PERC) is a high-production volume chemical and a ubiquitous environmental contaminant that is hazardous to human health. Toxicity of PERC is mediated through oxidative and glutathione conjugation metabolites. The conjugation of PERC by glutathione-s-transferase to generate S-(1,2,2-trichlorovinyl) glutathione (TCVG), which is subsequently metabolized to form S-(1,2,2-trichlorovinyl)-L-cysteine (TCVC) is of special importance to human health. Specifically, TCVC can be metabolized to N-acetyl-S-(1,2,2-trichlorovinyl)-L-cysteine (NAcTCVC) which is excreted through urine, or to electrophilic metabolites that are nephrotoxic and mutagenic. Little is known about toxicokinetics of TCVG, TCVC, and NAcTCVC as analytical methods for simultaneous determination of these metabolites in tissues have not yet been reported. Hence, an ultra-high performance liquid chromatography electrospray ionization tandem mass spectrometry-based method was developed for analysis of TCVG, TCVC, and NAcTCVC in liver, kidney, serum, and urine. The method is rapid, sensitive, robust, and selective for detection all three analytes in every tissue examined, with limits of detection ranging from 1.8–68.2 femtomoles on column, depending on the analyte and tissue matrix. This method can be applied to quantify levels of TCVG, TCVC, and NAcTCVC in tissues from mice treated with PERC (10 to 1000 mg/kg, orally) with limits of quantitation of 1–2.5 pmol/g in liver, 1–10 pmol/g in kidney, 1–2.5 pmol/mL in serum, and 2.5–5 pmol/mL in urine. This method is useful for further characterization of the glutathione conjugative pathway of PERC in vivo and improved understanding of PERC toxicity.

Characterization of inter-tissue and inter-strain variability of TCE glutathione conjugation metabolites DCVG, DCVC, and NAcDCVC in the mouse

“…The LC-MS/MS based method for simultaneous detection of DCVG and DCVC was developed for mouse serum (Kim et al, 2009a); however, applicability of this method to parenchymal tissues such as liver and kidney, especially at lower doses of TCE, was questionable. Yoo et al (2015a; 2015b) tailored extraction methods to quantify DCVG and DCVC in liver and kidney, respectively; but differences in extraction methods may still result in a systematic bias (Luo et al, 2017). In this study, tissue extraction protocols were optimized, the sensitivity of detection for DCVG and DCVC across tissues was further enhanced, and the method extended to quantification of NAcDCVC.…”

“…S308-0066; Phenomenex, Torrance, CA) was employed. The SPE procedure was slightly modified from our previously published method (Luo et al, 2017). In the final step, the dried residue was reconstituted in 30 µl water:methanol (9:1, v/v) containing 0.1% acetic acid.…”

Using Collaborative Cross Mouse Population to Fill Data Gaps in Risk Assessment: A Case Study of Population-Based Analysis of Toxicokinetics and Kidney Toxicodynamics of Tetrachloroethylene

“…Concentration–time profiles of TCVG, TCVC, and NAcTCVC in mouse liver, kidney, and serum were determined by using a liquid chromatography–tandem mass spectrometry (LC-MS/MS) method, as detailed elsewhere (Luo et al. 2017).…”

Incorporation of the glutathione conjugation pathway in an updated physiologically-based pharmacokinetic model for perchloroethylene in mice

“…Cichocki et al (2017a) suggested that a common method (gas chromatography) to analyze perc and TCA, was not suitable for the quantitation of conjugative metabolites because of their low abundance and quick clearance from tissue (Cichocki et al , 2017a). The recent development of a LC-MS/MS method has enabled investigation of toxicokinetics of a number of conjugation metabolites simultaneously, in serum and different tissues of mice (Luo et al , 2017).…”

“…Non-detects of perc, TCVG, TCVC and NAcTCVC in blood and liver (Cichocki et al , 2017a) and kidney (Supplementary Materials) were also included in the analysis, as it was found that these data were needed to place constraints on the clearance rate of the chemicals from blood and tissues. The limits of detection (LODs) reported in (Luo et al , 2017) are provided in Supplemental Material, Table S-3. It was assumed, as is standard in analytical chemistry, that the detection limit represents a response from a blank sample at 3 standard deviations.…”