Ethyl glucuronide identified in commercial hair tonics

Biomarkers for monitoring alcohol sobriety after liver transplantation for alcoholic liver disease

Alcoholic liver disease (ALD) has become the most common indication for liver transplantation in Western countries, and its incidence is rapidly increasing in East Asia. Alcohol abstinence remains the standard of care for promoting liver transplantation for ALD and for preventing posttransplant graft loss. However, efficient monitoring methods are still being developed due to the limitations of traditional biomarkers, interviews, and questionnaires. The development of alcohol biomarkers has shifted from detecting alcohol and methanol to indirect byproducts, and to current mid-term and long-term direct alcohol metabolites, which provide higher accuracy and cover almost all types of alcohol relapse detection. However, in most clinical studies, biomarkers are used and validated in healthy individuals and alcohol use disorder (AUD) patients and for pretransplant evaluations. The evidence for their use in posttransplant abstinence monitoring is still lacking, but it is crucial for early detection of alcohol relapse and initiating intervention. This review aims to summarize the current evidence of the use of biomarkers for monitoring sobriety and alcohol relapse after liver transplantation, as well as to cover the diagnostic accuracy, detection window, and optimal multidisciplinary strategies.

Beta-Glucuronidase Activity: Another Source of Ethyl Glucuronide

Numerous classes of endogenous and xenobiotic compounds are conjugated to uridine-5'-diphospho (UDP)-alpha-D-glucuronic acid which is catalyzed by human UDP-Glucuronosyltransferases (UGTs). The resulting beta-D-glucuronides can be hydrolyzed to β-D-glucuronic acid and the corresponding aglycone in a configuration retaining manner by beta-glucuronidases (GUSBs), which are widely distributed in mammalians, microbiota, insects, molluscs, nematodes, fishes and plants. This study investigates GUSBs' activity in the presence of ethanol (0-70% by volume) using different β-D-glucuronides (phenolphthalein-β-D-glucuronide, 4-nitrophenol-β-D-glucuronide, morphine-3-O-β-D-glucuronide, quercetin-3-O-β-D-glucuronide and 1-/2-propyl-β-D-glucuronide) as substrates. It was found that β-D-ethyl glucuronide (EtG), which is a minor UGT-derived metabolite of ethanol in man and one of the most frequently used biomarkers of alcohol consumption today, builds up from all investigated β-D-glucuronides by means of GUSBs in the presence of ethanol. The glucuronyl transfer reaction, which was neither detected in the absence of ethanol nor in absence of GUSBs, is minor at ethanol concentrations which are commonly observed in blood and tiβues after consumption of alcoholic beverages, but predominant at higher concentrations of ethanol. In spite of in vitro characteristics, our observations point to an additional biochemical path and another source of EtG, which should be further evaluated in the context of alcohol biomarker applications. The detection of EtG in several settings independent from of human UGT-metabolism (e.g. EtG post post-collection synthesis in E.coli coli-contaminated urine samples, EtG in wine and ethanolic herbal preparations) can be explained by the described mechanism.

EtG Quantification in Hair and Different Reference Cut-Offs in Relation to Various Pathologies: A Scoping Review

Ethyl glucuronide (EtG) is a non-volatile, non-oxidative, hydrophilic, and stable ethanol phase II metabolite. EtG is produced through ethanol glucuronidation by UDP-glucuronosyltransferase (UGT), a phase II enzyme. EtG can be extracted from different biological matrices, including keratin ones, such as hair or nails. The purpose of this scoping review is to describe the relationship between EtG levels in hair and some of the most common and frequent pathological conditions and verify whether different reference cut-offs in relation to various pathologies have been identified in the scientific literature. In fact, in-depth knowledge of the influence of pathologies, such as diabetes mellitus, hepatic and renal dysfunction, on EtG production and its storage in keratin matrices would allow a more appropriate interpretation of obtained data and rule out false positives or false negatives. This scoping review is based on bibliographic research carried out on PubMed regarding the quantification of EtG in hair of subjects affected by different pathological conditions. According to the scientific literature, the main and most common pathologies that can affect the concentration of EtG in hair are liver and kidney diseases and diabetes. The EtG quantification analytical data should be interpreted carefully as they may have a great impact in both forensic and clinical contexts.

Use of Ethanol-Based Hand Disinfectants: Source of Increased Ethyl Glucuronide Levels in Hair?

Aim

Due to the COVID-19 pandemic increasing the use of hand disinfectants, we investigated the effect of frequent use of ethanol-based hand disinfectants (EBHD) on the levels of the alcohol marker ethyl glucuronide (EtG) in hair.

Method

Hair samples were collected from 10 health professionals (8 nondrinkers, 2 rarely drinking individuals) and EtG was examined in hair.

Result

EtG (~2 pg/mg) was only detected in the hair sample of a nondrinker using EBHD 60–70 times per working day.

Conclusion

Our data provide no evidence that frequent EBHD use results in hair EtG levels above the recommended Society of Hair Testing cutoff for repeated alcohol consumption (5 pg/mg).

Impaired diagnostic accuracy of hair ethyl glucuronide testing in patients with renal dysfunction

The impact of renal impairment and hemodialysis on ethyl glucuronide concentrations in hair (hEtG) is not well known. Here, hEtG levels were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in patients presenting to the transplant outpatient clinic and compared with the self-reported alcohol consumption in an anonymous validated questionnaire. Estimated daily alcohol intake (EDI) was calculated. A total of 94 patients with varying renal function (Glomerular filtration rate (GFR) > 60 mL/min: group 1 (n = 47); GFR 30-60 ml/min: group 2 (n = 29); GFR < 30 mL/min: group 3 (n = 18)) were included in the study. Fifteen of 18 (83.3%) patients in group 3 were on dialysis. Altogether, hEtG tested positive (> 5 pg/mg) in 25.5% (n = 24) of patients, while 36.2% (n = 34) and 14.9% (n = 14) of patients reported any or regular (> 10 g/d) alcohol consumption, respectively. The median hEtG concentration of positive samples was much higher in patients in group 3 with advanced renal dysfunction or on dialysis than in patients in group 1 or 2 (group 1, 2, 3 dialysis patients: 74, 52, 145 and 155 pg/mg, respectively), although they consumed on average much less alcohol per day (median EDI group 1, 2, 3, dialysis patients: 16, 17, 3 and 3 g/d, respectively). Also, there was a significant correlation between the hEtG concentration and EDI for patients in group 1 (ρ = 0.84; p = 0.01), but not for patients in group 2 (ρ = -0.35, p = 0.39) or 3 (ρ = 0.02, p = 0.96). Furthermore, the ability of hEtG to correctly identify abstainers as such was lower for patients with advanced renal dysfunction than for the remaining patients (specificity for group 1, 2, 3: 92%, 87%, 82%, respectively). So, monitoring hEtG concentration was less reliable in patients with advanced renal dysfunction or on hemodialysis and by far overestimated the amount of alcohol consumed.

Positive findings of ethyl glucuronide in hair of young children from families with addiction background

AIMS

Small children are expected to be abstinent from alcohol, and children's hair is frequently used as the blank matrix for calibration of the alcohol consumption marker ethyl glucuronide (EtG). The basal EtG concentrations of total abstainers were described to be 0.3-2.1 pg/mg (Pirro et al. 2013). It is examined whether this assumption is valid for children from families with addiction background.

METHODS

In a social support system for families with drug and/or alcohol addicted parents, 161 hair samples from 126 children (age 1-14 years, hair segment 0-3 cm) were analyzed for EtG by a validated LC-MS/MS method (LOD 0.56 pg/mg, LLOQ 2.3 pg/mg). For comparison, ethyl palmitate (EtPa) was measured and hair samples from parents were included. EtG ≥ 3 pg/mg was considered as an alarming result for children.

RESULTS AND DISCUSSION

EtG concentrations between 3.0 and 42.6 pg/mg (mean 9.55 pg/mg, median 6.40 pg/mg) were measured for 25 samples (15.5%, age 22 × 1-5 years, 3 × 9-11 years). Elevated EtPa (0.15-0.46 ng/mg) was found in 6 samples and cocaethylene (0.02-0.07 ng/mg) was detected in 5 samples with high cocaine findings. Hair results of one or both parents indicated drug abuse in 12 from 14 cases (85.7%) if both parents were tested.

CONCLUSION

Although accidental or voluntary intake of alcoholic beverages cannot be excluded, the external contamination of children's hair by EtG-containing wine and sweat or urine of the alcohol abusing parents is assumed to be the most probable explanation for the positive EtG results in hair of 1-5-year-old children.

Ethyl glucuronide hair testing: A review

Ethyl glucuronide (EtG) is a minor, non-oxidative ethanol metabolite that can be detected in several matrices (e.g. blood, urine, hair, meconium) for variable periods of time. Quantification of EtG in hair (hEtG) has established itself, over recent years, as one of the most reliable biomarkers of long-term alcohol consumption habits, with the Society of Hair Testing (SoHT) offering cut-off values for assessment of both abstinence and heavy drinking (>60 g/day). Despite its high diagnostic performance, however, issues concerning inter- and intra-laboratory variability as well as data interpretation are still being investigated and represent the ultimate barrier to widespread acceptance of hEtG in the forensic context. The aim of this review is to summarize currently available analytical methods of hEtG testing, provide a framework to understand current hEtG cut-offs and their possible upcoming changes (in particular, a lower abstinence cut-off has been proposed for the 2019 revision of the SoHT consensus), and offer a schematic but exhaustive overview of the pitfalls in result reproducibility and interpretation that may limit applications of hEtG testing in the forensic context. Ultimately, the purpose of the authors is not to undermine the reliability of hEtG as an alcohol use marker, but rather to enhance it by promoting familiarization with all aspects related to it, from ethanol pharmacokinetics and EtG incorporation into hair, to sample preparation and analytical methods, to specific cases warranting close attention and additional tests for correct interpretation of hEtG results.

The influence of caffeine on ethyl glucuronide levels in rat serum and in rat hair

BACKGROUND

Ethanol and caffeine are the most widely used psychoactive substances in the world, with an observed steady increase in the combined consumption of alcohol and caffeine. Specific signs of ethanol-caffeine interactions have been reported both in humans and in animals. The metabolic effects of these interactions have not been fully elucidated. There are no published reports on the influence of caffeine on ethyl glucuronide (EtG) formation. EtG is a direct metabolite of ethanol and is very often used as a biomarker of alcohol consumption. Here, we investigated the influence of caffeine on the formation of EtG in rat plasma and EtG incorporation into the hair.

METHODS

Studies were conducted on three male Wistar rat groups, each receiving either ethanol at 3 g/kg/day, ethanol (at the same dose) with caffeine at 3 mg/kg/day, or caffeine at 3 mg/kg/day for four weeks. EtG and caffeine levels were evaluated in hair and in blood after the last administration.

RESULTS

Blood EtG levels after the administration of ethanol together with caffeine were significantly higher than after the administration of ethanol alone. EtG levels in rat hair in the ethanol-and-caffeine group were also higher than in the ethanol-only group, but the difference was not statistically significant.

CONCLUSION

This study shows the possible effect of ethanol and caffeine co-administration on EtG formation. Caffeine stimulates EtG synthesis resulting in increased blood and, possibly, hair levels of this metabolite. However, the role of these changes in estimating alcohol consumption requires further studies.

Ethyl Glucuronide in Alcoholic Beverages

Aims

This study examines the biomarker ethyl glucuronide (EtG) in various alcoholic beverages.

Short summary

The biomarker EtG was consistently found to be a natural compound of wine, whereas it was not detected in any of the other tested alcoholic beverages, which included various distilled spirits, liqueurs and beer of different types and geographical origins.

Methods

Alcoholic beverages (n = 114) were analyzed by a validated liquid chromatography/tandem mass spectrometry assay. Beverages included samples from beer, wine, liqueurs and spirits from different manufacturers and geographical origins.

Results

EtG was not detected in any kind of distilled alcoholic beverages, regardless of the type of spirit (rum, gin, vodka, whiskey, fruit brandy, corn brandy, cordial) or liqueur (n = 52). EtG was also not detected in any of the analyzed samples of beer, which included pilsener, weissbier, lager beer and ale from different origins (n = 20). In contrast, EtG was detected in every of the analyzed samples of wine (n = 42) without exception. Highest amounts were found in red wine and ranged from 1425 to 3720 μg/l (n = 16). Significantly, lower concentrations of EtG were observed for white wine (347-1685 μg/l, n = 14) and sparkling wine (281-1447 μg/l, n = 10).

Conclusions

Wine is an external source of EtG. It has been shown that milligram amounts of the biomarker can be contained in a bottle of wine. This should be considered in biomarker testing, especially in EtG hair analysis, which is susceptible to external contamination.

Biomarkers for detection of alcohol consumption in liver transplantation

Alcoholic liver disease is an established, yet controversial, indication for liver transplantation. Although an abstinence period of up to 6 mo prior to transplantation is mandatory, alcohol relapse after transplantation is a common event. In case of recurrence of heavy drinking, graft survival is significantly impaired. Guidelines on detection and surveillance of alcohol consumption in this patient cohort are lacking. This review summarizes the challenge of patient selection as well as the current knowledge on established and novel alcohol biomarkers with special focus on liver transplant candidates and recipients.

Multiple stage MS in analysis of plasma, serum, urine and in vitro samples relevant to clinical and forensic toxicology

This paper reviews MS approaches applied to metabolism studies, structure elucidation and qualitative or quantitative screening of drugs (of abuse) and/or their metabolites. Applications in clinical and forensic toxicology were included using blood plasma or serum, urine, in vitro samples, liquids, solids or plant material. Techniques covered are liquid chromatography coupled to low-resolution and high-resolution multiple stage mass analyzers. Only PubMed listed studies published in English between January 2008 and January 2015 were considered. Approaches are discussed focusing on sample preparation and mass spectral settings. Comments on advantages and limitations of these techniques complete the review.

Determination of ethyl glucuronide in hair to assess excessive alcohol consumption in a student population

Hair analysis for ethyl glucuronide (EtG) was used to evaluate the pattern of alcohol consumption amongst the Portuguese university student population. A total of 975 samples were analysed. For data interpretation, the 2014 guidelines from the Society of Hair Testing (SoHT) for the use of alcohol markers in hair for the assessment of both abstinence and chronic excessive alcohol consumption were considered. EtG concentrations were significantly higher in the male population. The effect of hair products and cosmetics was evaluated by analysis of variance (ANOVA), and significant lower concentrations were obtained when conditioner or hair mask was used or when hair was dyed. Based on the analytical data and information obtained in the questionnaires from the participants, receiver operating characteristic (ROC) curves were constructed in order to determine the ideal cut-offs for our study population. Optimal cut-off values were estimated at 7.3 pg/mg for abstinence or rare occasional drinking control and 29.8 pg/mg for excessive consumption. These values are very close to the values suggested by the SoHT, proving their adequacy to the studied population. Overall, the obtained EtG concentrations demonstrate that participants are usually well aware of their consumption pattern, correlating with the self-reported consumed alcohol quantity, consumption habits and excessive consumption close to the time of hair sampling.

Biomolecules and Biomarkers Used in Diagnosis of Alcohol Drinking and in Monitoring Therapeutic Interventions

BACKGROUND

The quantitative, measurable detection of drinking is important for the successful treatment of alcohol misuse in transplantation of patients with alcohol disorders, people living with human immunodeficiency virus that need to adhere to medication, and special occupational hazard offenders, many of whom continually deny drinking. Their initial misconduct usually leads to medical problems associated with drinking, impulsive social behavior, and drunk driving. The accurate identification of alcohol consumption via biochemical tests contributes significantly to the monitoring of drinking behavior.

METHODS

A systematic review of the current methods used to measure biomarkers of alcohol consumption was conducted using PubMed and Google Scholar databases (2010-2015). The names of the tests have been identified. The methods and publications that correlate between the social instruments and the biochemical tests were further investigated. There is a clear need for assays standardization to ensure the use of these biochemical tests as routine biomarkers.

FINDINGS

Alcohol ingestion can be measured using a breath test. Because alcohol is rapidly eliminated from the circulation, the time for detection by this analysis is in the range of hours. Alcohol consumption can alternatively be detected by direct measurement of ethanol concentration in blood or urine. Several markers have been proposed to extend the interval and sensitivities of detection, including ethyl glucuronide and ethyl sulfate in urine, phosphatidylethanol in blood, and ethyl glucuronide and fatty acid ethyl esters in hair, among others. Moreover, there is a need to correlate the indirect biomarker carbohydrate deficient transferrin, which reflects longer lasting consumption of higher amounts of alcohol, with serum γ-glutamyl transpeptidase, another long term indirect biomarker that is routinely used and standardized in laboratory medicine.

Influence of thermal hair straightening on ethyl glucuronide content in hair

Hair analysis of ethyl glucuronide (EtG) has become a valuable marker for the detection of moderate and chronic alcohol consumption. It has been shown that bleaching and perming may decrease EtG content in hair. So far, no studies exist about the influence of thermal hair straightening on EtG content in hair. Forty-one positive EtG hair samples were treated in vitro with a hair straightener at 200°C. Duration of treatment of 1 min was chosen for this study. After washing, pulverization, incubation in ultrasonic bath, solid-phase extraction, and derivatization with heptafluorobutyric anhydride, EtG was determined by gas chromatography-mass spectrometry - negative ion chemical ionization (GC-MS-NICI). The EtG contents in straightened hair strands were then compared with those in the corresponding untreated strands. In 20 of 41 hair samples, a decrease of EtG content was found ranging from 0.7% to 79.3% (average 20%) whereas in 21 cases an increase was shown ranging from 2.0% to 50.9% (average 15%). The variation of the results seems to depend on hair colour. The decrease may be explained by thermic in vitro destruction of EtG. The increase may be explained by denaturation of the hair matrix by thermal treatment possibly causing a better extraction of EtG during incubation in ultrasonic bath. This in vitro study indicates that thermal hair straightening has an impact on the EtG content in hair. This has to be considered for a correct interpretation of EtG results in hair. However, these results should be confirmed by in vivo studies.

A comparison between serum carbohydrate-deficient transferrin and hair ethyl glucuronide in detecting chronic alcohol consumption in routine

AIMS

In heavy alcohol consumption laboratory tests represent an objective evidence. In this study we compared older and newer biomarkers in blood and in hair.

METHODS

Carbohydrate-deficient transferrin (CDT), ethyl glucuronide (EtG), AST, ALT, GGT, MCV were measured in a large sample (n = 562). All people declared no alcohol consumption within the last 3 months. Serum CDT was measured by the candidate HPLC reference method and expressed as relative amount of disialotransferrin (%DST: cutoff 1.7%). EtG was measured in hair by a validated in-house method by LC-MS/MS (cutoff 30 pg/mg).

RESULTS

Respectively, 42 (7.5%) and 76 (13.5%) subjects were positive to CDT and EtG. In particular, 30 (5.3%) subjects were positive to both tests, 12 (2.1%) only to CDT, while 46 (8.2%) only to EtG. The agreement (positive and negative pairs) between CDT and EtG was 89.7%. Interestingly, 6 out of 12 (50%) CDT-positive subjects had EtG < 15 pg/mg, whereas 27 out of 46 (59%) EtG-positive subjects had CDT < 1.1%. Forty-one out of 76 (54%) EtG-positive subjects display EtG values within 30-50 pg/mg.

CONCLUSION

Large variability exists between CDT and EtG in detecting chronic alcohol consumption. We suggest to use CDT, or a combination of different biomarkers, to identify alcohol abuse in a forensic context. EtG results close to the cutoff (30-50 pg/mg) should be cautiously considered before any sanction is assigned.

Ethyl glucuronide and ethyl sulfate

Alcohol misuse is associated with significant morbidity and mortality. Although clinical history, examination, and the use of self-report questionnaires may identify subjects with harmful patterns of alcohol use, denial or under-reporting of alcohol intake is common. Existing biomarkers for detecting alcohol misuse include measurement of blood or urine ethanol for acute alcohol consumption, and carbohydrate-deficient transferrin and gamma-glutamyl transferase for chronic alcohol misuse. There is a need for a biomarker that can detect excessive alcohol consumption in the timeframe between 1 day and several weeks. Ethyl glucuronide (EtG) is a direct metabolite of ethanol detectable in urine for up to 90 h and longer in hair. Because EtG has high specificity for excess alcohol intake, it has great potential for use in detecting "binge" drinking. Using urine or hair, this noninvasive marker has a role in a variety of clinical and forensic settings.

Hair ethyl glucuronide levels as a marker for alcohol use and abuse: a review of the current state of the art

BACKGROUND

Ethyl glucuronide (EtG) is a minor alcohol metabolite that has been proposed as a stable marker in hair to detect and quantify alcohol consumption over long time periods.

METHODS

We provide an outline of currently available techniques for EtG hair sample analysis and highlight the pitfalls related to data interpretation. The literature of EtG analysis has been reviewed from January 1980 up to August 2013. In addition, we present an overview of the clinical and forensic studies which have used EtG quantification in hair as a marker for alcohol consumption/abstinence and we provide suggestions for future research.

RESULTS

EtG is a stable marker in hair that can be used to detect and quantify alcohol consumption over long time periods. This alcohol metabolite remains in hair after complete elimination of alcohol. Currently, there are three main analytical techniques used to quantify EtG in hair: gas chromatography-mass spectrometry (GC-MS), gas chromatography-tandem mass spectrometry (GC-MS/MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS). No standardized protocols are yet available for the analysis of EtG levels in hair samples, and the current protocols vary in sample preparation and extraction procedures. Variables such as hair length, cosmetic treatment, gender, and pathophysiological conditions influence the final results and should be taken into account.

CONCLUSIONS

EtG quantification in hair is a useful tool for the objective detection of alcohol consumption over extended time periods, but care should be taken when interpreting the results.