Comparison of ethyl glucuronide and carbohydrate-deficient transferrin in different body fluids for post-mortem identification of alcohol use

Brief history of the alcohol biomarkers CDT, EtG, EtS, 5-HTOL, and PEth

This article traces the historical development of various biomarkers of acute and/or chronic alcohol consumption. Much of the research in this domain of clinical and laboratory medicine arose from clinics and laboratories in Sweden, as exemplified by carbohydrate deficient transferrin (CDT) and phosphatidylethanol (PEth). Extensive studies of other alcohol biomarkers, such as ethyl glucuronide (EtG), ethyl sulfate (EtS), and 5-hydroxytryptophol (5-HTOL), also derive from Sweden. The most obvious test of recent drinking is identification of ethanol in a sample of the person's blood, breath, or urine. However, because of continuous metabolism in the liver, ethanol is eliminated from the blood at a rate of 0.15 g/L/h (range 0.1-0.3 g/L/h), so obtaining positive results is not always possible. The widow of detection is increased by analysis of ethanol's non-oxidative metabolites (EtG and EtS), which are more slowly eliminated from the bloodstream. Likewise, an elevated ratio of serotonin metabolites in urine (5-HTOL/5-HIAA) can help to disclose recent drinking after ethanol is no longer measurable in body fluids. A highly specific biomarker of hazardous drinking is CDT, a serum glycoprotein (transferrin), with a deficiency in its N-linked glycosylation. Another widely acclaimed biomarker is PEth, an abnormal phospholipid synthesized in cell membranes when people drink excessively, having a long elimination half-life (median ~6 days) during abstinence. Research on the subject of alcohol biomarkers has increased appreciably and is now an important area of drug testing and analysis.

Predictive risk markers in alcoholism

The medical disorders of alcoholism rank among the leading public health problems worldwide and the need for predictive and prognostic risk markers for assessing alcohol use disorders (AUD) has been widely acknowledged. Early-phase detection of problem drinking and associated tissue toxicity are important prerequisites for timely initiations of appropriate treatments and improving patient's committing to the objective of reducing drinking. Recent advances in clinical chemistry have provided novel approaches for a specific detection of heavy drinking through assays of unique ethanol metabolites, phosphatidylethanol (PEth) or ethyl glucuronide (EtG). Carbohydrate-deficient transferrin (CDT) measurements can be used to indicate severe alcohol problems. Hazardous drinking frequently manifests as heavy episodic drinking or in combinations with other unfavorable lifestyle factors, such as smoking, physical inactivity, poor diet or adiposity, which aggravate the metabolic consequences of alcohol intake in a supra-additive manner. Such interactions are also reflected in multiple disease outcomes and distinct abnormalities in biomarkers of liver function, inflammation and oxidative stress. Use of predictive biomarkers either alone or as part of specifically designed biological algorithms helps to predict both hepatic and extrahepatic morbidity in individuals with such risk factors. Novel approaches for assessing progression of fibrosis, a major determinant of prognosis in AUD, have also been made available. Predictive algorithms based on the combined use of biomarkers and clinical observations may prove to have a major impact on clinical decisions to detect AUD in early pre-symptomatic stages, stratify patients according to their substantially different disease risks and predict individual responses to treatment.

Evaluation of the Compatibility of Ethyl Glucuronide and Ethyl Sulphate Levels to Assess Alcohol Consumption in Decomposed and Diabetic Postmortem Cases

The aim of the study is to evaluate the contribution of ethanol metabolite detection in postmortem cases by showing the connection between the presence of ethanol metabolites, which are indicators of alcohol consumption, and the detection of potential postmortem ethanol formation in decomposed and diabetic cases. Determination of ethanol consumption before death is often one of the most important questions in death investigations. Postmortem ethanol formation or degradation products in the blood make it difficult to distinguish antemortem consumption or postmortem formation of ethanol and eventually may lead to misinterpretation. Decomposed bodies and diabetic cases are vulnerable to postmortem ethanol formation due to putrefaction, fermentation or other degradations. Ethyl glucuronide (EtG) and ethyl sulphate (EtS) are two metabolites of ethanol produced only in the antemortem time interval. In this study, EtG and EtS levels in urine and vitreous humor samples of 27 postmortem cases, including diabetic and degraded bodies were compared to ethanol results of their blood, urine, and vitreous humor samples. EtG and EtS in urine and vitreous humor were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS-MS) and ethanol was assayed by routine headspace gas chromatography-flame ionization detector (GC-FID). These cases were devoid of other influences from forensically relevant drugs, so ethanol and/or glucose were among the only positive findings in these cases. The results of this pilot study indicate the postmortem ethanol concentrations do not correlate with the measured EtG and EtS values but are beneficial in rulings of accidental or natural deaths. This preliminary study gives additional data to help distinguish between antemortem ethanol intake and postmortem formation. EtG and EtS were well correlated positively with antemortem ethanol use instead of forming spontaneously in samples from decedents who are decomposing or have a history of diabetic hyperglycemia.

Ethyl glucuronide and ethanol concentrations in femoral blood, urine and vitreous humor from 117 autopsy cases

BACKGROUND

Vitreous humor (VH) is a specimen of great value in forensic investigations and is being used for evaluating possible post-mortem formation of ethanol. Ethyl glucuronide (EtG) is an ethanol metabolite that has found interest for the same purpose. Both compounds can be measured in VH and because of differences in rate of distribution and elimination they may offer complementary information.

METHODS

VH, femoral blood (FB) and urine were collected from 117 autopsy cases for forensic investigation. Ethanol was measured with headspace gas chromatography, while EtG was measured with liquid chromatography - tandem mass spectrometry.

RESULTS AND CONCLUSION

Ethanol was detected in all matrices in 39 cases, while EtG was present in 62 cases. The VH-FB and the VH-urine ethanol concentrations in the 39 cases were statistically correlated (p < 0.00001). In one case with an ethanol concentration of 0.11 g/L in FB, no ethanol was detected in VH and urine, and no EtG in any specimen, indicating a possible post-mortem formation. EtG was present in VH in more cases than in FB and urine. The correlation between the EtG concentrations in VH and FB was statistically significant (p < 0.0003) as was the case also for VH and urine (p < 0.001). The combined information on ethanol and EtG concentrations in the three matrices can be used to interpret alcohol drinking habit before death. This study confirms the value of using VH as a specimen in forensic investigations regarding recent exposure to ethanol. EtG can be used not only for investigating post-mortem ethanol formation but also for estimating recent alcohol drinking.

Evaluation and review of ways to differentiate sources of ethanol in postmortem blood

Accurate determination of a person's blood alcohol concentration (BAC) is an important task in forensic toxicology laboratories because of the existence of statutory limits for driving a motor vehicle and workplace alcohol testing regulations. However, making a correct interpretation of the BAC determined in postmortem (PM) specimens is complicated, owing to the possibility that ethanol was produced in the body after death by the action of various micro-organisms (e.g., Candida species) and fermentation processes. This article reviews various ways to establish the source of ethanol in PM blood, including collection and analysis of alternative specimens (e.g., bile, vitreous humor (VH), and bladder urine), the identification of non-oxidative metabolites of ethanol, ethyl glucuronide (EtG) and ethyl sulfate (EtS), the urinary metabolites of serotonin (5-HTOL/5-HIAA), and identification of n-propanol and n-butanol in blood, which are known putrefaction products. Practical utility of the various biomarkers including specificity and stability is discussed.

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.

Analytical and diagnostic aspects of carbohydrate deficient transferrin (CDT): A critical review over years 2007-2017

The need for investigating alcohol abuse by means of objective tools is worldwide accepted. Among the currently available biomarkers of chronic alcohol abuse, carbohydrate-deficient transferrin (CDT) is one of the most used indicator, mainly because of its high specificity. However, some CDT analytical and interpretation aspects are still under discussion, as witnessed by numerous research papers and reviews. The present article presents a critical review of the literature on CDT appeared in the period from 2007 to 2017 (included). The article is organized in the following sections: (1) introduction, (2) pre-analytical aspects (3) analytical aspects (4) diagnostic aspects (5) concluding remarks. As many as 139 papers appeared in the international literature and retrieved by the search engines PubMed, Web of Science and Scopus are quoted.

Biomarker-Based Approaches for Assessing Alcohol Use Disorders

Although alcohol use disorders rank among the leading public health problems worldwide, hazardous drinking practices and associated morbidity continue to remain underdiagnosed. It is postulated here that a more systematic use of biomarkers improves the detection of the specific role of alcohol abuse behind poor health. Interventions should be initiated by obtaining information on the actual amounts of recent alcohol consumption through questionnaires and measurements of ethanol and its specific metabolites, such as ethyl glucuronide. Carbohydrate-deficient transferrin is a valuable tool for assessing chronic heavy drinking. Activities of common liver enzymes can be used for screening ethanol-induced liver dysfunction and to provide information on the risk of co-morbidities including insulin resistance, metabolic syndrome and vascular diseases. Conventional biomarkers supplemented with indices of immune activation and fibrogenesis can help to assess the severity and prognosis of ethanol-induced tissue damage. Many ethanol-sensitive biomarkers respond to the status of oxidative stress, and their levels are modulated by factors of life style, including weight gain, physical exercise or coffee consumption in an age- and gender-dependent manner. Therefore, further attention should be paid to defining safe limits of ethanol intake in various demographic categories and establishing common reference intervals for biomarkers of alcohol use disorders.

Human plasma protein N-glycosylation

Glycosylation is the most abundant and complex protein modification, and can have a profound structural and functional effect on the conjugate. The oligosaccharide fraction is recognized to be involved in multiple biological processes, and to affect proteins physical properties, and has consequentially been labeled a critical quality attribute of biopharmaceuticals. Additionally, due to recent advances in analytical methods and analysis software, glycosylation is targeted in the search for disease biomarkers for early diagnosis and patient stratification. Biofluids such as saliva, serum or plasma are of great use in this regard, as they are easily accessible and can provide relevant glycosylation information. Thus, as the assessment of protein glycosylation is becoming a major element in clinical and biopharmaceutical research, this review aims to convey the current state of knowledge on the N-glycosylation of the major plasma glycoproteins alpha-1-acid glycoprotein, alpha-1-antitrypsin, alpha-1B-glycoprotein, alpha-2-HS-glycoprotein, alpha-2-macroglobulin, antithrombin-III, apolipoprotein B-100, apolipoprotein D, apolipoprotein F, beta-2-glycoprotein 1, ceruloplasmin, fibrinogen, immunoglobulin (Ig) A, IgG, IgM, haptoglobin, hemopexin, histidine-rich glycoprotein, kininogen-1, serotransferrin, vitronectin, and zinc-alpha-2-glycoprotein. In addition, the less abundant immunoglobulins D and E are included because of their major relevance in immunology and biopharmaceutical research. Where available, the glycosylation is described in a site-specific manner. In the discussion, we put the glycosylation of individual proteins into perspective and speculate how the individual proteins may contribute to a total plasma N-glycosylation profile determined at the released glycan level.

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.

Prevalence of alcohol-related pathologies at autopsy: Estonian Forensic Study of Alcohol and Premature Death

AIMS

Alcohol can induce diverse serious pathologies, yet this complexity may be obscured when alcohol-related deaths are classified according to a single underlying cause. We sought to quantify this issue and its implications for analysing mortality data.

DESIGN, SETTING AND PARTICIPANTS

Cross-sectional study included 554 men aged 25-54 in Estonia undergoing forensic autopsy in 2008-09.

MEASUREMENTS

Potentially alcohol-related pathologies were identified following macroscopic and histological examination. Alcohol biomarkers levels were determined. For a subset (26%), drinking behaviour was provided by next-of-kin. The Estonian Statistics Office provided underlying cause of death.

FINDINGS

Most deaths (75%) showed evidence of potentially alcohol-related pathologies, and 32% had pathologies in two or more organs. The liver was most commonly affected [60.5%, 95% confidence interval (CI) = 56.3-64.6] followed by the lungs (18.6%, 95% CI = 15.4-22.1), stomach (17.5%, 95% CI = 14.4-20.9), pancreas (14.1%, 95% CI = 11.3-17.3), heart (4.9%, 95% CI = 3.2-7.0) and oesophagus (1.4%, 95% CI = 0.6-2.8). Only a minority with liver pathology had a second pathology. The number of pathologies correlated with alcohol biomarkers (phosphatidylethanol, gamma-glytamyl transpeptidase in blood, ethylglucuronide, ethylsulphate in urine). Despite the high prevalence of liver pathology, few deaths had alcoholic liver disease specified as the underlying cause.

CONCLUSION

The majority of 554 men aged 25-54 undergoing forensic autopsy in Estonia in 2008-09 showed evidence of alcohol-related pathology. However, the recording of deaths by underlying cause failed to capture the scale and nature of alcohol-induced pathologies found.

Alcohol hangover as a cause of impairment in apprehended drivers

OBJECTIVE

Previous studies have already shown the possibility of impairment during a hangover phase, after alcohol ingestion, when the blood alcohol concentration has returned to zero. The prevalence of drivers being in a hangover phase, in the driving population, and the relation to impairment relevant for traffic safety has, however, not been previously studied. The aim of this study was to investigate the prevalence and the concentrations of the 2 ethanol metabolites, ethyl glucuronide (EtG) and ethyl sulfate (EtS), in blood, indicating very recent alcohol intake, among apprehended drivers, in which no psychoactive substances, including alcohol, were detected. The aim was also to study these findings in relation to the impairment observed in these drivers.

METHODS

Blood samples, drawn from suspected drunk or drugged drivers, were analyzed for a broad repertoire of psychoactive substances, with a clinical test for impairment (CTI) being performed at the same time. One hundred and forty-six cases, in which no psychoactive substances were detected and where a valid CTI was performed, were analyzed for EtG and EtS in blood. The prevalence and concentrations were related to the conclusions of the CTIs.

RESULTS

EtS and EtG were detected in a total of 19 of the 146 cases (13%). Among the "impaired" drivers, EtG and EtS were detected in 16 cases (18%), whereas among "not impaired" drivers they were detected in 3 cases (5%). There were significantly more detections of EtS (and EtG) among the impaired group of drivers compared to the nonimpaired drivers (P =.030), and the concentrations of both EtG (P =.027) and EtS (P =.026) were significantly higher in the group of impaired drivers compared to the nonimpaired drivers. There was a statistically significant positive correlation between the concentrations of EtG (Spearman's rho = 0.170, P =.041) and EtS (Spearman's rho = 0.189, P =.022) and the degree of impairment.

CONCLUSIONS

EtG and EtS were prevalent findings in blood collected from the apprehended drivers, testing negative for all psychoactive substances. The higher rates of detections of EtG and EtS in impaired compared to nonimpaired drivers, and also the positive correlation between concentrations of EtG and EtS and the degree of impairment, indicate that hangover symptoms may be relevant for traffic safety.

The UDP-glucuronosyltransferases of the blood-brain barrier: their role in drug metabolism and detoxication

UDP-glucuronosyltransferases (UGTs) form a multigenic family of membrane-bound enzymes expressed in various tissues, including brain. They catalyze the formation of β-D-glucuronides from structurally unrelated substances (drugs, other xenobiotics, as well as endogenous compounds) by the linkage of glucuronic acid from the high energy donor, UDP-α-D-glucuronic acid. In brain, UGTs actively participate to the overall protection of the tissue against the intrusion of potentially harmful lipophilic substances that are metabolized as hydrophilic glucuronides. These metabolites are generally inactive, except for important pharmacologically glucuronides such as morphine-6-glucuronide. UGTs are mainly expressed in endothelial cells and astrocytes of the blood brain barrier (BBB). They are also associated to brain interfaces devoid of BBB, such as circumventricular organ, pineal gland, pituitary gland and neuro-olfactory tissues. Beside their key-role as a detoxication barrier, UGTs play a role in the steady-state of endogenous compounds, like steroids or dopamine (DA) that participate to the function of the brain. UGT isoforms of family 1A, 2A, 2B and 3A are expressed in brain tissues to various levels and are known to present distinct but overlapping substrate specificity. The importance of these enzyme species with regard to the formation of toxic, pharmacologically or physiologically relevant glucuronides in the brain will be discussed.

Alcohol: Pharmacology and Disposition

Alcohol is the most common drug detected in forensic cases, is often associated with increased aggression and other disinhibitory behaviors in criminal matters, and frequently contributes to the cause of death in medical examiner cases. Significant adverse effects of alcohol generally manifest at blood alcohol concentrations above 100 mg/dL. In postmortem cases, a number of factors can affect the accuracy of the blood measurement, including site of sampling and putrefactive formation. This paper provides an overview of the pharmacology, pharmacokinetics, and interpretation of alcohol and its concentrations in key specimens, with application to forensic medical cases.

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.