N-Acetyltaurine as a novel urinary ethanol marker in a drinking study

Abstract

The forensic utility of N-acetyltaurine (NAcT) in urine as a marker for ethanol intake was examined. A HILIC-based liquid chromatography method for the mass spectrometric determination of NAcT, taurine, and creatinine in urine was developed and validated to investigate NAcT formation and elimination in a drinking study. Thereby, eight subjects ingested 0.66 to 0.84 g/kg alcohol to reach a blood alcohol concentration (BAC) of 0.8 g/kg. Blood and urine were taken every 1.5-2 h, during the first 8 h. NAcT and taurine levels were measured and corrected for the urine's dilution by normalization to a creatinine concentration of 1 mg/mL. For the determination of NAcT and taurine, uncorrected lower limits of quantitation (LLOQs) were at 0.05 μg/mL of urine. In the drinking study, NAcT proved to be an endogenous compound, which is present at a range of 1.0 to 2.3 μg/mL in urine of alcohol-abstinent subjects. Maximum NAcT concentrations were reached in samples taken 3 to 6 h after the start of drinking, whereby an upregulation in N-acetyltaurine could be found for all the subjects. The mean peak concentrations (c̅ max) of 14 ± 2.6 μg/mL (range 9-17.5 μg/mL) were reached. Within 24 h, the NAcT levels declined to endogenous concentrations. The detectability of NAcT was found to be slightly shifted compared to BAC: When BAC was not detectable anymore, NAcT levels were still elevated. After 24 h, when ethyl glucuronide (EtG) and ethyl sulfate (EtS) were still detectable, NAcT concentrations showed endogenous levels again. Positive NAcT results can be used as an indicator for recent alcohol consumption. A direct relationship between NAcT and taurine concentrations could not be found. Graphical abstract N-acetyltaurine concentrations for eight subjects during the first 24 h after an alcohol consumption of 0.8 g/kg.

Creatinine in urine – a method comparison

“…Eighty‐nine urine samples used in this study were obtained from eight healthy volunteers participating in a drinking study . A further 111 samples reached the institute of forensic medicine for routine analysis (driving under the influence of drugs) and were analyzed for their creatinine concentration.…”

“…Eighty-nine urine samples used in this study were obtained from eight healthy volunteers participating in a drinking study. [8] A further 111 samples reached the institute of forensic medicine for routine analysis (driving under the influence of drugs) and were analyzed for their creatinine concentration. The determination of the creatinine concentration by spectrophotometry represents a standard procedure which is generally performed for all urine samples sent to our laboratory.…”

“…Sample preparation, analysis, and validation has recently been described in detail. [8] Briefly, 50 μL of urine and 150 μL acetonitrile containing the internal standard (creatinine-d 3 ) were shaken for several minutes. After centrifugation, the supernatant was taken and evaporated to dryness.…”

Metabolomic and Lipidomic Biomarkers for Premalignant Liver Disease Diagnosis and Therapy

“…NAT is not specific to alcohol exposure, since it has been described as a biomarker of gamma-irradiation in both rats [63] and rhesus monkeys [64]. NAT urinary excretion has been reported in healthy human subjects who drank alcohol (0.66 to 0.84 g/kg) [65]. In blood, NAT concentration as a biomarker of alcohol exposure was of limited value [66].…”

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

“…By investigation of direct alcohol markers within different matrices, evidence of both, short-and long-term consumption can be obtained for high and low doses of alcohol. The most promising direct alcohol biomarker to monitor regular alcohol consumption was found in phosphatidylethanol (PEth), as the pharmacokinetic characteristics provide a long detection window when compared to other direct alcohol biomarkers such as ethyl glucuronide, ethyl sulfate, fatty acid ethyl esters or N-acetyltaurine (3)(4)(5)(6)(7). Unlike hair analysis, which is generally used for the assessment of drinking behavior over a longer time period, PEth determination in blood or organ tissue can serve as an intermediary long term marker without being subject to washout effects (8)(9)(10).…”