Evaluation of N-acetyltaurine as an ethanol marker in human blood

Development and validation of an analytical method for the simultaneous determination of the alcohol biomarkers ethyl glucuronide, ethyl sulfate, N-acetyltaurine, and 16:0/18:1-phosphatidylethanol in human blood

As alcohol is the most common addictive substance worldwide, it is inevitable to advance the established research. New and more substantial analytical methods can be applied to reply to complex questions in legal or forensic contexts. Therefore, an analytical method for the simultaneous determination of four different alcohol biomarkers-ethyl glucuronide, ethyl sulfate, N-acetyltaurine, and 16:0/18:1-phosphatidylethanol-in human blood was developed, validated, and verified. Despite the different chemical properties of the analytes, a specific determination via HPLC-MS/MS was achieved using a novel type of a Phenomenex Luna® Omega Sugar column. Furthermore, all criteria for a successful validation were fulfilled according to forensic guidelines. The method proved to be linear and demonstrates selectivity and sufficient sensitivity for every biomarker. LODs obtained with this method of 2.6 ng/ml (EtG), 4.7 ng/ml (EtS), 12.5 ng/ml (NAcT), and 6.9 ng/ml (PEth) were in an acceptable range for routine applications, and the stability of all analytes over a range of 12 h is given. The verification of the new developed method was performed with authentic samples. Thus, whole blood and postmortem samples were analyzed to obtain information about the drinking behavior, which can answer complex questions regarding alcohol consumption.

Investigation of the detoxification effect of licorice on Semen Strychni-induced acute toxicity in rats using a HPLC-Q-TOF/MS-based metabolomics approach

Semen Strychni, a traditional Chinese medicine (TCM), has been widely used to treat paraplegia, facial nerve palsy and myasthenia gravis. However, its clinical application is greatly limited due to its fatal toxicity. To investigate the acute toxicity of Semen Strychni and the detoxification effect of licorice, a high-performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF/MS) based urinary metabolomics method was developed in this study. After intraperitoneal injection to rats with Semen Strychni extract, the serum biochemical indexes were changed significantly, the liver and kidney showed severe necrosis and edema. Then the poisoned rat model was subsequently used for metabolomics research. Through principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA), we finally identified 19 endogenous differential metabolites involved in amino acid metabolism, glycerophospholipid metabolism, tricarboxylic acid (TCA) cycle, oxidative stress and energy metabolism. In addition, 4 exogenous compounds from Semen Strychni (3 prototypes and 1 metabolite) were also identified in the present study. Results showed that the alterations of 23 compounds caused by Semen Strychni were significantly reversed after licorice treatment, which indicated that restoring the endogenous metabolic disorder and accelerating the metabolism of the main toxic components might be the possible detoxification mechanisms of licorice. This study may provide an integral understanding for the acute toxicity of Semen Strychni and the detoxification effect of licorice, thereby contributing to the clinical use of Semen Strychni and licorice.

Metabolomic and Lipidomic Biomarkers for Premalignant Liver Disease Diagnosis and Therapy

In recent years, there has been a plethora of attempts to discover biomarkers that are more reliable than α-fetoprotein for the early prediction and prognosis of hepatocellular carcinoma (HCC). Efforts have involved such fields as genomics, transcriptomics, epigenetics, microRNA, exosomes, proteomics, glycoproteomics, and metabolomics. HCC arises against a background of inflammation, steatosis, and cirrhosis, due mainly to hepatic insults caused by alcohol abuse, hepatitis B and C virus infection, adiposity, and diabetes. Metabolomics offers an opportunity, without recourse to liver biopsy, to discover biomarkers for premalignant liver disease, thereby alerting the potential of impending HCC. We have reviewed metabolomic studies in alcoholic liver disease (ALD), cholestasis, fibrosis, cirrhosis, nonalcoholic fatty liver (NAFL), and nonalcoholic steatohepatitis (NASH). Specificity was our major criterion in proposing clinical evaluation of indole-3-lactic acid, phenyllactic acid, N-lauroylglycine, decatrienoate, N-acetyltaurine for ALD, urinary sulfated bile acids for cholestasis, cervonoyl ethanolamide for fibrosis, 16α-hydroxyestrone for cirrhosis, and the pattern of acyl carnitines for NAFL and NASH. These examples derive from a large body of published metabolomic observations in various liver diseases in adults, adolescents, and children, together with animal models. Many other options have been tabulated. Metabolomic biomarkers for premalignant liver disease may help reduce the incidence of HCC.

Formation of phosphatidylethanol from endogenous phosphatidylcholines in animal tissues from pig, calf, and goat

In the presence of alcohol, phosphatidylcholine (PC) is transformed to the direct alcohol biomarker phosphatidylethanol (PEth). This reaction is catalyzed by the enzyme phospholipase D (PLD) and dependent on substrate availability. As recent methods have solely focused on the determination of PEth, information about the PC composition was generally missing. To address this issue and monitor PC (16:0/18:1 and 16:0/18:2) and PEth (16:0/18:1 and 16:0/18:2) simultaneously, a reversed phase LC-MS/MS method based on a C8 core-shell column, coupled to a Sciex 5500 QTrap instrument was developed. By application of polarity switching, at first, PC was measured in ESI positive SRM mode, while PEth was determined at a later stage in ESI negative SRM mode. The PEth method was validated for human blood samples to show its robustness and subsequently applied for the investigation of systematic in vitro PEth formation in animal tissue samples (brain, kidney, liver, and blood) from a pig, a calf, and a goat. Homogenized tissue was incubated at 37°C with varying ethanol concentrations from 1 to 7g/kg (determined by HS-GC-FID) for 5h, whereby a sample was taken every 30min. For all tissue samples, an increase in PEth was measurable. PEth concentrations formed in blood remained below the LLOQ, in agreement with literature. Data analysis of Michaelis-Menten kinetics and PC within the tissue provided a detailed insight about PEth formation, as the occurrence of PEth species can be linked to the observed PC composition. The results of this study show that PEth formation rates vary from tissue to tissue and among different species. Furthermore, new recommendations for PEth analysis are presented.