Normalization rate and cellular localization of phosphatidylethanol in whole blood from chronic alcoholics

Phosphatidylethanol in post-mortem brain: Correlation with blood alcohol concentration and alcohol use disorder

Phosphatidylethanol (PEth) is an alcohol derivative that has been employed as a blood-based biomarker for regular alcohol use. This study investigates the utility of phosphatidylethanol (PEth) as a biomarker for assessing alcohol consumption in post-mortem brain tissue. Using samples from the New South Wales Brain Tissue Resource Centre, we analysed PEth(16:0/18:1) levels in the cerebellum and meninges of individuals with varying histories of alcohol use, including those diagnosed with alcohol use disorder (AUD) and controls. Our findings demonstrate a significant correlation between PEth levels and blood alcohol content (BAC) at the time of death, supporting the biomarker's sensitivity to recent alcohol intake. Furthermore, this study explores the potential of PEth levels in differentiating AUD cases from controls, taking into consideration the complexities of diagnosing AUD post-mortem. The study also examined the relationship between PEth levels and liver pathology, identifying a link with the severity of liver damage. These results underscore the value of PEth as a reliable indicator of alcohol consumption and its potential contributions to post-mortem diagnostics and consequently, research into alcohol-related brain damage.

Phosphatidylethanol is a promising tool for screening alcohol consumption during pregnancy

BACKGROUND

Prenatal alcohol exposure (PAE) is one of the leading causes of preventable developmental disabilities. A lack of objective screening methods results in an under-recognition of the phenomenon. Phosphatidylethanol (PEth) is a specific ethanol biomarker that reveals alcohol intake up to several weeks after alcohol use. So far, PEth has mostly been a tool for detecting moderate and heavy drinking. With lower PEth cut-offs, revealing even minor prenatal alcohol consumption is possible. We aimed to find out if a sensitive method for PEth analysis would give additional information about PAE and to assess the cut-off value for a positive alcohol result in prenatal screening.

METHODS

The study was an observational study of 3000 anonymous blood samples collected from the Helsinki University Hospital Diagnostic Center between June and September 2023. The Finnish Red Cross Blood Service received the samples originally for blood group typing and antibody screening as part of the prenatal blood screening program. We developed a sensitive PEth 16:0/18:1 analysis method using ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) equipment after liquid-liquid extraction of PEth from whole blood. The lower limit of quantification was 1 ng/mL.

RESULTS

PEth was ≥2 ng/mL in 5.2% of the cases, ≥8 ng/mL in 2.0%, and ≥20 ng/mL in 1.0%. The detection time of PEth can be several weeks, especially with low PEth concentrations and after heavy alcohol consumption. It remained unknown whether the positive PEth tests resulted from drinking deliberately during pregnancy or before pregnancy recognition.

CONCLUSIONS

We suggest adding PEth 16:0/18:1 to a routine prenatal blood screening program with a cut-off of 2 ng/mL-and in positive cases, clinical evaluation and retesting in 2-4 weeks. In clinical settings, information on gestational week and alcohol consumption before pregnancy is relevant and needs to be considered when interpreting low PEth concentrations.

Identification of Alcohol Use Prior to Major Cancer Surgery: Timeline Follow Back Interview Compared to Four Other Markers

BACKGROUND

The postoperative complication rate is 30-64% among patients undergoing muscle-invasive and recurrent high-risk non-muscle-invasive bladder cancer surgery. Preoperative risky alcohol use increases the risk. The aim was to evaluate the accuracy of markers for identifying preoperative risky alcohol.

METHODS

Diagnostic test sub-study of a randomized controlled trial (STOP-OP trial), based on a cohort of 94 patients scheduled for major bladder cancer surgery. Identification of risky alcohol use using Timeline Follow Back interviews (TLFB) were compared to the AUDIT-C questionnaire and three biomarkers: carbohydrate-deficient transferrin in plasma (P-CDT), phosphatidyl-ethanol in blood (B-PEth), and ethyl glucuronide in urine (U-EtG).

RESULTS

The correlation between TLFB and AUDIT-C was strong (ρ = 0.75), while it was moderate between TLFB and the biomarkers (ρ = 0.55-0.65). Overall, sensitivity ranged from 56 to 82% and specificity from 38 to 100%. B-PEth showed the lowest sensitivity at 56%, but the highest specificity of 100%. All tests had high positive predictive values (79-100%), but low negative predictive values (42-55%).

CONCLUSIONS

Despite high positive predictive values, negative predictive values were weak compared to TLFB. For now, TLFB interviews seem preferable for preoperative identification of risky alcohol use.

Pilot Randomized Controlled Trial of Game Plan for PrEP: A Brief, Web and Text Message Intervention to Help Sexual Minority Men Adhere to PrEP and Reduce Their Alcohol Use

Suboptimal adherence to oral PrEP medications, particularly among younger sexual minority men (SMM), continues to be a key barrier to achieving more substantial declines in new HIV infections. Although variety of interventions, including web and text-message-based applications, have successfully addressed PrEP adherence, very few have addressed the potential influence of alcohol. This pilot study explored whether the Game Plan for PrEP, a brief, web-based and text messaging intervention, helped promote PrEP persistence and adherence and reduced condomless sex and alcohol use. Seventy-three heavy-drinking SMM on PrEP were recruited online from states with Ending the HIV Epidemic jurisdictions and randomly assigned 1:1 to receive either the Game Plan for PrEP intervention or an attention-matched control. We collected online surveys assessing primary outcomes at one, three, and six months post-enrollment. As secondary outcomes, we also collected dried blood spot samples at baseline, three, and six months to analyze for biomarkers of PrEP and alcohol use. Our results showed that the odds of stopping PrEP or experiencing a clinically meaningful lapse in PrEP adherence (≥ 4 consecutive missed doses) were not different across the two conditions. We also did not find evidence of any differences in condomless sex or drinking outcomes across conditions, although participants in both conditions reported drinking less often over time. These findings were consistent across both self-reported outcomes and biomarkers. Overall, we did not find evidence that our brief, web and text messaging intervention encouraged more optimal PrEP coverage or moderate their alcohol use.

Phosphatidylethanol (B-PEth) and other direct and indirect biomarkers of alcohol consumption

When identifying, preventing and treating alcohol use disorder, a correct estimation of alcohol intake is essential. An objective marker is preferred as self-reported alcohol intake suffers from bias, and the use of alcohol biomarkers is increasing globally. An easy-to-use blood biomarker to correctly assess alcohol consumption is an invaluable asset in alcohol treatment strategies, as well as in alcohol research studies. The specific, cumulative, biomarker phosphatidylethanol, mirroring the past two weeks of consumption, has shown superiority over traditional biomarkers and is an attractive choice of proxy for alcohol intake.

A randomized, double-blind, placebo-controlled, multicentre trial on the efficacy of varenicline and bupropion in combination and alone for treatment of alcohol use disorder: Protocol for the COMB study

BACKGROUND

Alcohol Use Disorder (AUD) is a major cause of premature death, disability and suffering. Available treatments are of modest efficacy and under-prescribed so there is a pressing need for a well-tolerated and effective treatment option for AUD. Dopamine is hypothesized to be involved in the development of alcohol dependence. To challenge the low-dopamine hypothesis of addiction, this randomized, double-blind, placebo-controlled, 13-week, multicentre clinical trial with four parallel arms is designed to evaluate the efficacy of two substances raising dopamine levels, varenicline and bupropion, alone and in combination vs. placebo on alcohol consumption in AUD. Varenicline, a partial agonist at brain nicotinic acetylcholine receptors increases dopamine release, whereas bupropion is a centrally-acting, norepinephrine-dopamine reuptake inhibitor. Varenicline is previously shown to reduce alcohol intake in individuals with AUD. We hypothesize that the effect size of a combination of two drugs affecting dopamine levels in the brain will exceed that of approved AUD therapies.

METHODS

Consenting individuals with AUD will be recruited via media advertisements. Those fulfilling the eligibility criteria (N = 380) will be randomized to one of four interventions (n = 95 per arm). Treatment will comprise one week of titration (varenicline 0.5‒2 mg; bupropion SR 150‒300 mg) plus 12 weeks at steady state. Efficacy will be evaluated using two primary endpoints of alcohol consumption: Heavy Drinking Days and blood levels of phosphatidylethanol. Secondary objectives, exploratory and subgroup analyses will be also performed. The modified Intention-to-Treat and Per Protocol datasets will be evaluated using Analysis of Covariance. Last patient out is estimated to occur in December, 2022.

DISCUSSION

The COMB Study aims to evaluate the efficacy of the combination of varenicline and bupropion, two drugs affecting dopamine, on alcohol consumption, and to challenge the low-dopamine hypothesis of addiction. Study Code COMB-BO8, EudraCT 2018-000048-24, Version 3.2, Lidö & deBejczy, 2020-06-16; https://clinicaltrials.gov identifier NCT04167306.

Formation of phosphatidylethanol and ethylglucuronide after low to moderate alcohol consumption in volunteers with a previous three-week alcohol abstinence

AIMS

Phosphatidylethanol (PEth) is only formed when ethanol is present in blood. This direct alcohol marker has been widely discussed, including the minimum amount of ethanol being necessary to form as much PEth as to exceed the threshold of 20 ng/mL in previously PEth negative subjects. In order to corroborate hitherto existing results, a drinking study including 18 participants after a 3-week alcohol abstinence was performed.

METHODS

They consumed a pre-calculated amount of ethanol to reach a blood alcohol concentration (BAC) of at least 0.6 g/kg. Blood was drawn before and periodically seven times after alcohol administration on day 1. Blood and urine were also collected the next morning. Dried blood spots (DBS) were prepared immediately from collected venous blood. BAC was determined by head space gas chromatography and the concentrations of both PEth (16:0/18:1, 16:0/18:2 and five additional homologues) and ethyl glucuronide (EtG) were analysed using liquid chromatography-tandem mass spectrometry.

RESULTS

Out of 18, 5 participants had concentrations of PEth 16:0/18:1 above the threshold of 20 ng/mL, and 11 out of the 18 subjects had concentrations between 10 and 20 ng/mL. In addition, four persons had PEth 16:0/18:2 concentrations above 20 ng/mL the following morning. All test subjects tested positive for EtG in DBS (≥ 3 ng/mL) and urine (≥100 ng/mL) upon 20-21 h after alcohol administration.

CONCLUSION

By combining both a lower cutoff of 10 ng/mL and the homologue PEth 16:0/18:2, the sensitivity to detect a single alcohol intake after a 3-week abstinence increases to 72.2%.

The alcohol biomarker phosphatidylethanol (PEth) - test performance and experiences from routine analysis and external quality assessment

Phosphatidylethanol (PEth) are membrane molecules formed from phosphatidylcholine and ethanol through transphosphatidylation catalyzed by phospholipase D. Measurement of the main PEth form 16:0/18:1 is used as a specific and sensitive alcohol biomarker, since its formation requires ethanol, it accumulates in the blood upon repeated ethanol exposure, and it is only slowly eliminated during abstinence. PEth formation correlates with alcohol intake at the population level, albeit with considerable inter-individual variation as for the half-life during withdrawal. Over the past decade, the use of PEth has increased significantly and the applications have broadened. In Sweden, routine decision limits and the interpretation of test results for PEth were harmonized in 2013, using < 0.05 µmol/L (∼35 µg/L) as the recommended lower reporting limit and values > 0.30 µmol/L (∼210 µg/L) to indicate regular high alcohol intake. Routine test results show a large variation with about half being < 0.05 µmol/L and some even exceeding 10 µmol/L. In 2013, an external quality assessment (EQA) scheme for PEth 16:0/18:1 measurement in whole blood was also started (Equalis, Uppsala, Sweden), presently involving 56 laboratories from 13 countries. The agreement of PEth results between the laboratories has gradually improved to a CV < 15%. The current clinical and scientific information suggests that PEth values below the lower reporting limit (typically ∼0.03-0.05 µmol/L, or ∼20-35 µg/L) indicates sobriety or only low or occasional alcohol consumption, while regular high alcohol intake at levels corresponding to harmful drinking is required in most cases to reach PEth values > 0.30 µmol/L.

Development of an LC-MS/MS assay with automated sample preparation for phosphatidylethanol (PEth)- Not your typical clinical marker

Phosphatidylethanol (PEth) is a group of phospholipids formed exclusively in the presence of ethanol on the erythrocyte membrane, making it a direct biomarker for long-term ethanol consumption for which a clinical reference interval has been established. Here, we describe an assay for quantitation for two most abundant PEth homologues, PEth 16:0/18:1 and PEth 16:0/18:2, from human whole blood, and present challenges overcome throughout the development process. Since PEth is localized within erythrocyte membranes, a reliable sample preparation technique is an important aspect of PEth analysis. Therefore, various erythrocyte lysing agents for recovery of exogenously spiked standards and controls were evaluated to identify one that performed comparably to the recovery of endogenous analytes found in authentic samples. A supported liquid extraction (SLE) technique was employed for sample cleanup and enrichment which together with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis enabled automated sample preparation, appropriate chromatographic resolution, and minimal system carryover. This resulted in a laboratory developed test with an analytical measurement range (AMR) of 10-1000 ng/mL (slope = 0.9902-1.0138, R2 = 0.9958-0.9972), that was precise (intra-day precision: 3.4-4.1%; inter-day precision: 4.4-8.2% over the AMR), accurate when compared with an available external laboratory test (slope = 0.9943-1.0206, R2 = 0.9635-0.9678, no lower decision point interpretation changes), with effective analyte recovery (77.2-83.5%), and established stability characteristics, while chromatographically separating the analytes to ensure no additive effects due to the isotopic distribution of the opposing analyte.

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.

Phosphatidylethanol (PEth) in Blood as a Marker of Unhealthy Alcohol Use: A Systematic Review with Novel Molecular Insights

The Alcohol Use Disorders Identification Test (AUDIT) and its short form, the AUDIT-C, the main clinical instruments used to identify unhealthy drinking behaviors, are influenced by memory bias and under-reporting. In recent years, phosphatidylethanol (PEth) in blood has emerged as a marker of unhealthy alcohol use. This systematic review aims to investigate the molecular characteristics of PEth and summarize the last ten years of published literature and its use compared to structured questionnaires. A systematic search was performed, adhering to PRISMA guidelines, through "MeSH" and "free-text" protocols in the databases PubMed, SCOPUS, and Web of Science. The inclusion criteria were as follows: PEth was used for detecting unhealthy alcohol consumption in the general population and quantified in blood through liquid chromatography coupled to mass spectrometry, with full texts in the English language. Quality assessment was performed using the JBI critical appraisal checklist. Twelve papers were included (0.79% of total retrieved records), comprising nine cross-sectional studies and three cohort studies. All studies stratified alcohol exposure and quantified PEth 16:0/18:1 through liquid chromatography coupled to mass spectrometry (LC-MS) in liquid blood or dried blood spots (DBS) with lower limits of quantitation (LLOQ) ranging from 1.7 ng/mL to 20 ng/mL. A correlation between blood PEth level and the amount of alcohol ingested in the previous two weeks was generally observed. PEth interpretative cut-offs varied greatly among the included records, ranging from 4.2 ng/mL to 250 ng/mL, with sensitivity and specificity in the ranges of 58-100% and 64-100%, respectively. Although the biomarker seems promising, further research elucidating the variability in PEth formation and degradation, as well as the molecular mechanisms behind that variability, are necessary.

Role of Biomarkers to Assess the Use of Alcohol

Alcohol-associated liver disease has seen a significant rise in the last 2 decades, with an associated rise in the need for accurate alcohol use assessment. Alcohol use has been associated with poor outcomes in both the pre-liver transplant and post-liver transplant patients. Patients with alcohol use disorder often under-report their alcohol consumption because of varying factors, highlighting the need for objective assessment of alcohol use. Aside from the available self-report questionnaires, multiple serologic biomarkers are currently available to assist clinicians to assess recent alcohol consumption among patients with chronic liver disease, liver transplant candidates, and recipients. In this review, we will assess some of these alcohol biomarkers, discuss their strengths and weakness, and review-available data to discuss their role in pre-liver transplant and post-liver transplant population.

Development and Validation of Seven Phosphatidylethanol Homologues in Dried Blood Spots Including Preliminary Results after Excessive Use of an Ethanol-Based Hand Sanitizer

Phosphatidylethanol (PEth) has become a widespread marker offering an up to 4-week retrospective window to detect alcohol use. Due to the pandemic of coronavirus disease 2019, ethanol-based hand sanitizers are frequently used. The aim of this study was to develop and validate a method for the determination of up to seven different homologues of PEth from dried blood spots (DBSs) after use of an ethanol-based hand sanitizer. The objectives of its preliminary application were to prove whether a threshold of 20 ng/mL for PEth 16:0/18:1 is reached and whether other homologues are formed as well as if positive findings of urinary ethyl glucuronide (UEtG) can be observed with respect to assess monitoring of abstinence control programs. Ten volunteers (8 occasional and 2 regular drinkers) were recruited to excessively use an ethanol-based hand sanitizer on 5 successive days. DBSs and urine samples were collected daily. PEth and UEtG were determined by liquid chromatography--tandem mass spectrometry. In total, two volunteers with initial PEth 16:0/18:1 concentrations of 19.3 and 14.6 ng/mL exceeded the threshold of 20 ng/mL six times. Subjects drinking daily or almost daily had starting PEth 16:0/18:1 concentrations of 242 and 354 ng/mL, showing a decline of PEth concentrations in six out of the seven homologues over 5 days. In teetotalers, formation of PEth species could not be observed. Thus, not satisfying requirements in an alcohol monitoring program with initial PEth-negative blood cannot be explained by a frequent use of ethanol-based hand sanitizer only. In cases of regular alcohol consumption, PEth homologues are not likely to be further influenced. However, results indicated that individuals with a PEth concentration close to 20 ng/mL are at risk of exceeding the threshold by using ethanol-based hand sanitizer.

Alcohol Biomarker Phosphatidylethanol as a Predictor of the Severity of Alcohol Withdrawal Syndrome

AIMS

to investigate the relationship between phosphatidylethanol (PEth) and withdrawal severity in patients with alcohol use disorder (AUD).

METHODS

in 34 patients with AUD admitted for treatment of acute alcohol withdrawal, data were available for initial blood PEth concentrations and scores throughout detoxification of symptoms of withdrawal assessed by trained medical staff using the alcohol withdrawal syndrome (AWS)-scale, a validated scale consisting of 11 items in the alcohol withdrawal syndrome (two subscales with seven physiological and five psychological symptoms).

RESULTS

a significant positive correlation between PEth and the severity of alcohol withdrawal was found. When the sample was divided into two groups, according to whether or not AWS score at some point in the treatment reached 6 or more, the median PEth score was higher in those whose peak score had been 6 or more (score of 6 being the suggested cutoff to start medicating the withdrawal syndrome). Although there was a trend for some aspects of the clinical history to be more 'severe' in those with higher AWS, no differences reached significance.

CONCLUSION

blood PEth on admission could have a role in identifying patients at risk of more severe AWS.

False Positive Results of Phosphatidylethanol (PEth) Quantitation in Dried Blood Spots (DBS): The Influence of Alcohol Vapors

The role of phosphatidylethanol (PEth) as an alcohol consumption marker is increasing in clinical and forensic medicine. During the COVID-19 pandemic, the role of hygiene increased, and it became common practice to use disinfectants almost everywhere. This paper highlights a possible source of false positive results (by the vapors of alcohols during the blood spot drying process) in dried blood spots (DBS) by LC-MS/MS quantitation of PEth. To achieve this, the PEth quantitation method was validated according to FDA guidelines. Additionally, the synthesis of phosphatidyl derivatives by phospholipase D (PLD) in the presence of methanol and 2-propanol vapors during the DBS process was determined. Each PEth-negative sample from a healthy male patient incubated in the presence of ethanol vapor becomes PEth-positive. After 4 h of DBS drying, teetotalers become “moderate drinkers”. It is necessary to avoid using alcohol-containing disinfectants in treatment rooms, where DBS is sampled.

Set-up of a population-based model to verify alcohol abstinence via monitoring of the direct alcohol marker phosphatidylethanol 16:0/18:1

BACKGROUND AND AIMS

Phosphatidylethanol 16:0/18:1 (PEth) is a biomarker for alcohol intake. It has a half-life of 7.9 days. Chronic alcohol consumption causes high PEth values. It can take weeks before PEth values fall below the decision limit for 'alcohol abstinence'. Our aim was to validate whether alcohol abstinence can be determined based on two consecutive PEth results above the decision limit.

DESIGN

Observational study.

SETTING

Belgium, February 2019. The study was linked to a social initiative in Belgium, 'Tournée Minérale'.

PARTICIPANTS

Adults (aged > 18 years, n = 796) with varying drinking habits who self-reportedly refrained from alcohol consumption during the study.

MEASUREMENTS

A validated liquid chromatography-tandem mass spectrometry method was used to quantify PEth in participants' dried blood samples, collected at three time-points via remote fingerprick-based self-sampling.

FINDINGS

A population-based algorithm to evaluate abstinence based on 95% prediction limits was developed by fitting a linear mixed-effect model to discern patterns in PEth elimination over time. It took intra- and inter-individual variability into consideration. The algorithm was included in a two-step decision tree, assessing whether (i) PEth values fell within the prediction interval and (ii) the slope between two PEth values was consistent with no alcohol consumption. Data for 74 participants reporting no alcohol intake during the study were used for validation. With a detection limit of 'four units spread over 14 days', the sensitivity and specificity of the decision tree was 89%.

CONCLUSIONS

Claims of alcohol abstinence can be verified using a two-step decision tree for phosphatidylethanol 16:0/18:1 values, even when those values are above the limit for 'alcohol abstinence'.

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.

Fully automated correction for the hematocrit bias of non-volumetric dried blood spot phosphatidylethanol analysis

The quantitative analysis of substances in dried blood spots (DBS) has gained vast popularity in the past decade. The World Anti-Doping Agency (WADA) also recently committed to implementing DBS. Currently, DBS sampling mainly has focused on various volumetric sampling devices such as Hemaxis, Capitainer, and Mitra. These devices are designed to collect a specific sample volume, independent of the hematocrit (HCT), to enable quantitative DBS analysis. Here, we present an automated solution that makes the necessity of volumetric sampling for quantitative DBS analysis obsolete. Combining automated reflectance-based HCT correction in combination with fully automated DBS LC-MS/MS analysis, the novel strategy permits high-throughput analysis in combination with HCT independence. Studying the model compound phosphatidylethanol 16:0/18:1, which is HCT-dependent due to incorporation into red blood cells, an implementation of DBS HCT normalization is presented. First, the performance of the automated HCT module with DBS is demonstrated compared to standardized HCT analysis from whole blood using a centrifuge. Second, the HCT dependency of fully automated PEth analysis from DBS is evaluated. Third, a solution to correct for the HCT dependency of PEth using the HCT scanner is presented. The study demonstrates that as soon as the HCT dependence of an analyte is known, a correction factor can be applied for the normalization of HCT levels. In the context of PEth, a linear increase in PEth concentration was observed, as the analyte is primarily located within the cellular fraction. Based on the obtained results, the use of a common correction factor for PEth DBS is possible.

Factors associated with phosphatidylethanol (PEth) sensitivity for detecting unhealthy alcohol use: An individual patient data meta-analysis

BACKGROUND

Objective measurement of alcohol consumption is important for clinical care and research. Adjusting for self-reported alcohol use, we conducted an individual participant data (IPD) meta-analysis to examine factors associated with the sensitivity of phosphatidylethanol (PEth), an alcohol metabolite, among persons self-reporting unhealthy alcohol consumption.

METHODS

We identified 21 eligible studies and obtained 4073 observations from 3085 participants with Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) positive scores (≥3 for women and ≥4 for men) and PEth measurements. We conducted 1-step IPD meta-analysis using mixed effects models with random intercepts for study site. We examined the associations between demographic (sex, race/ethnicity, and age) and biologic (body mass index-BMI, hemoglobin, HIV status, liver fibrosis, and venous versus finger-prick blood collection) variables with PEth sensitivity (PEth≥8 ng/ml), adjusting for the level of self-reported alcohol use using the AUDIT-C score.

RESULTS

One third (31%) of participants were women, 32% were African, 28% African American, 28% White, and 12% other race/ethnicity. PEth sensitivity (i.e., ≥8 ng/ml) was 81.8%. After adjusting for AUDIT-C, we found no associations of sex, age, race/ethnicity, or method of blood collection with PEth sensitivity. In models that additionally included biologic variables, those with higher hemoglobin and indeterminate and advanced liver fibrosis had significantly higher odds of PEth sensitivity; those with higher BMI and those living with HIV had significantly lower odds of PEth sensitivity. African Americans and Africans had higher odds of PEth sensitivity than whites in models that included biologic variables.

CONCLUSIONS

Among people reporting unhealthy alcohol use, several biological factors (hemoglobin, BMI, liver fibrosis, and HIV status) were associated with PEth sensitivity. Race/ethnicity was associated with PEth sensitivity in some models but age, sex, and method of blood collection were not. Clinicians should be aware of these factors, and researchers should consider adjusting analyses for these characteristics where possible.

The Association between the Alcohol Biomarker Phosphatidylethanol (PEth) and Self-Reported Alcohol Consumption among Russian and Norwegian Medical Patients

Aims

Valid measures to identify harmful alcohol use are important. Alcohol Use Disorders Identification Test (AUDIT) is a validated questionnaire used to self-report harmful drinking in several cultures and settings. Phosphatidylethanol 16:0/18:1 (PEth) is a direct alcohol biomarker measuring alcohol consumption levels. The aim of this study was to investigate how PEth levels correlate with AUDIT-QF and weekly grams of alcohol consumed among patients in two urban hospitals. In addition, we wanted to investigate the predictive value of PEth in identifying harmful alcohol use as defined by AUDIT-QF and weekly grams of alcohol cutoffs.

Methods

A cross-sectional study comprising acute medically ill patients with measurable PEth levels (≥0.030 μM) admitted to two urban hospitals in Oslo, Norway (N = 931) and Moscow, Russia (N = 953) was conducted using PEth concentrations in whole blood, sociodemographic data and AUDIT-QF questionnaires.

Results

PEth levels from patients with measurable PEth were found to be positively correlated with AUDIT-QF scores, with PEth cutpoints of 0.128 μM (Oslo) and 0.270 μM (Moscow) providing optimal discrimination for harmful alcohol use defined by AUDIT-QF (the difference between cities probably reflecting different national drinking patterns in QF). When converting AUDIT-QF into weekly grams of alcohol consumed, the predictive value of PEth improved, with optimal PEth cutpoints of 0.327 (Oslo) and 0.396 (Moscow) μM discriminating between harmful and non-harmful alcohol use as defined in grams (≥350 grams/week).

Conclusions

By using PEth levels and converting AUDIT-QF into weekly grams of alcohol it was possible to get an improved rapid and sensitive determination of harmful alcohol use among hospitalized patients.

Stability of phosphatidylethanol 16:0/18:1 in authentic and spiked whole blood

Phosphatidylethanol 16:0/18:1 (PEth) is the most abundant homologue of the phosphatidylethanol group of phospholipids. Formed only in the presence of ethanol, PEth is used as a biomarker in whole blood to provide information about the consumption of alcohol. As information on the storage life of PEth is essential for its beneficial use as a biomarker, this study investigated the stability of PEth in spiked and authentic whole blood samples stored at 4°C. Human whole blood samples (n = 23) and spiked whole blood samples (n = 7) with a concentration range between 5 and 2000 ng/ml were analysed at specific time intervals, up to 90 days. Differences were evident between the stability of authentic and spiked samples. PEth was stable at 4°C for 60 days (concentrations within 15% of initial concentration) in authentic samples, whereas spiked samples were stable for up to 30 days. This study emphasizes the importance of including authentic samples in stability experiments.

Diagnostic Accuracy of Biomarkers of Alcohol Use in Patients With Liver Disease: A Systematic Review

BACKGROUND AND AIMS

Alcohol-related liver disease is the most frequent cause of cirrhosis and a major indication for liver transplantation. Several alcohol use biomarkers have been developed in recent years and are already in use in several centers. However, in patients with liver disease their diagnostic performance might be influenced by altered biomarker formation by hepatic damage, altered excretion by kidney dysfunction and diuretics use, and altered deposition in hair and nails. We systematically reviewed studies on the diagnostic accuracy of biomarkers of alcohol use in patients with liver disease and performed a detailed study quality assessment.

METHODS

A structured search in PubMed/Medline/Embase databases was performed for relevant studies, published until April 28, 2019. The risk of bias and applicability concerns was assessed according to the adapted quality assessment of diagnostic accuracy studies-2 (QUADAS-2) checklist.

RESULTS

Twelve out of 6,449 studies met inclusion criteria. Urinary ethyl glucuronide and urinary ethyl sulfate showed high sensitivity (70 to 89 and 73 to 82%, respectively) and specificity (93 to 99 and 86 to 89%, respectively) for assessing any amount of alcohol use in the past days. Serum carbohydrate-deficient transferrin showed low sensitivity but higher specificity (40 to 79 and 57 to 99%, respectively) to detect excessive alcohol use in the past weeks. Whole blood phosphatidylethanol showed high sensitivity and specificity (73 to 100 and 90 to 96%, respectively) to detect any amount of alcohol use in the previous weeks. Scalp hair ethyl glucuronide showed high sensitivity (85 to 100%) and specificity (97 to 100%) for detecting chronic excessive alcohol use in the past 3 to 6 months. Main limitations of the current evidence are the lack of an absolute gold standard to assess alcohol use, heterogeneous study populations, and the paucity of studies.

CONCLUSIONS

Urinary and scalp hair ethyl glucuronide are currently the most validated alcohol use biomarkers in patients with liver disease with good diagnostic accuracies. Phosphatidylethanol is a highly promising alcohol use biomarker, but so far less validated in liver patients. Alcohol use biomarkers can complement each other regarding diagnostic time window. More validation studies on alcohol use biomarkers in patients with liver disease are needed.

Quantitative determination of phosphatidylethanol in dried blood spots for monitoring alcohol abstinence

Phosphatidylethanol (PEth), which is formed by enzymatic reaction between ethanol and phosphatidylcholine, is a direct marker for alcohol usage. PEth has a long elimination half-life (~5-10 d) and specimens can be sampled using minimally invasive microsampling strategies. In combination with rapid analysis procedures PEth has proved to be advantageous for the detection of abstinence over other direct (e.g., ethyl glucuronide in blood, urine or hair) and indirect (e.g., carbohydrate-deficient transferrin in serum) alcohol markers. Although PEth determination is widely applied around the world, laboratory protocols are not standardized. Here we provide general guidelines for the analysis of PEth in dried blood spots (DBSs), including reference material evaluation, synthesis of a deuterated internal standard, preparation of calibration samples (reference material in teetotaller blood), and analyte separation and detection. The protocol contains information to extract the DBSs either manually or with a fully automated autosampler. Extraction of the analytes from DBS filter paper cards is performed using an organic extraction, followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). For accurate and reliable measurement of PEth, the two most abundant analogs, PEth 16:0/18:1 and PEth 16:0/18:2, are quantified. We show data that provide guidelines on how to interpret the results for both demographic studies and forensic applications. The described protocol can be applied by experienced laboratory staff with basic LC-MS/MS knowledge and takes 2 d to perform.

Phosphatidylethanol Reliably and Objectively Quantifies Alcohol Consumption in Adolescents and Young Adults

BACKGROUND

Alcohol contributes to numerous annual deaths and various societal problems not just in adult, but also in adolescent, populations. Therefore, it is vital to find methods for reliably detecting alcohol use for early preventative measures. Research has shown phosphatidylethanol (PEth) to be superior to self-report instruments and indirect biomarkers for alcohol consumption in adult populations. However, the transferability onto an adolescent population has not yet been investigated.

METHODS

N = 106 adolescents and young adults aged between 13 and 21 years were included. PEth analysis using high-pressure liquid chromatography-tandem mass spectrometry was performed on dried blood spot samples. Self-report questionnaires for alcohol consumption (Alcohol Use Disorders Identification Test-Consumption, AUDIT-C, and Timeline Followback, TLFB) and drug and alcohol consumption (Detection of Alcohol and Drug Problems in Adolescents, DEP-ADO) were completed by each participant.

RESULTS

AUDIT-C scores showed large correlations with PEth 16:0/18:1 (r_s  = 0.732) and PEth 16:0/18:2 (r_s  = 0.661) concentrations. AUDIT-C with a cutoff value ≥3 was largely correlated with PEth 16:0/18:1 (η = 0.411) and showed a medium-sized correlation with PEth 16:0/18:2 (η = 0.397) concentrations. Using an AUDIT-C cutoff value ≥5 showed large correlations with both PEth 16:0/18:1 (η = 0.510) and PEth 16:0/18:2 (η = 0.497) concentrations, respectively. ROC curves indicated higher PEth concentrations are a good model for detecting positive AUDIT-C cutoff values (AUROC range: 0.800 to 0.849). PEth concentrations showed medium to large correlations with DEP-ADO and TLFB subscales (range r_s  = 0.469 to 0.746).

CONCLUSION

The results suggest that PEth is a reliable and objective marker for quantifying alcohol consumption in adolescents and young adults. This could be of importance for early preventative measures against hazardous alcohol consumption, which is increasingly common at younger ages.

What the lab can and cannot do: clinical interpretation of drug testing results

Urine drug testing is one of the objective tools available to assess adherence. To monitor adherence, quantitative urinary results can assist in differentiating "new" drug use from "previous" (historical) drug use. "Spikes" in urinary concentration can assist in identifying patterns of drug use. Coupled chromatographic-mass spectrometric methods are capable of identifying very small amounts of analyte and can make clinical interpretation rather challenging, specifically for drugs that have a longer half-life. Polypharmacy is common in treatment and rehabilitation programs because of co-morbidities. Medications prescribed for comorbidities can cause drug-drug interaction and phenoconversion of genotypic extensive metabolizers into phenotypic poor metabolizers of the treatment drug. This can have significant impact on both pharmacokinetic (PK) and pharmacodynamic properties of the treatment drug. Therapeutic drug monitoring (TDM) coupled with PKs can assist in interpreting the effects of phenoconversion. TDM-PKs reflects the cumulative effects of pathophysiological changes in the patient as well as drug-drug interactions and should be considered for treatment medications/drugs used to manage pain and treat substance abuse. Since only a few enzyme immunoassays for TDM are available, this is a unique opportunity for clinical laboratory scientists to develop TDM-PK protocols that can have a significant impact on patient care and personalized medicine. Interpretation of drug screening results should be done with caution while considering pharmacological properties and the presence or absence of the parent drug and its metabolites. The objective of this manuscript is to review and address the variables that influence interpretation of different drugs analyzed from a rehabilitation and treatment programs perspective.

Elimination Characteristics of the Alcohol Biomarker Phosphatidylethanol (PEth) in Blood during Alcohol Detoxification

Aims

The study documented elimination characteristics of three phosphatidylethanol (PEth) homologs in serially collected blood samples from 47 heavy drinkers during ~2 weeks of alcohol detoxification at hospital.

Methods

Venous whole blood and urine samples were collected every 1–2 days during treatment. Concentrations of PEth, and of urinary ethyl glucuronide (EtG) and ethyl sulfate (EtS) to detect relapse drinking, were measured using liquid chromatography-tandem mass spectrometry.

Results

When included in the study, negative or decreasing breath ethanol concentrations demonstrated that the patients were in the elimination phase. The EtG and EtS measurements further confirmed alcohol abstinence during the study, with three exceptions. On admission, all patients tested positive for PEth, the total concentration ranging 0.82–11.7 (mean 6.35, median 5.88) μmol/l. PEth 16:0/18:1, 16:0/18:2 and 16:0/20:4 accounted for on average ~42%, ~26% and ~9%, respectively, of total PEth in these samples. There were good correlations between total PEth and individual homologs (P < 0.0001). There was no significant difference in PEth values between male and female subjects. During abstinence, the elimination half-life values ranged 3.5–9.8 days for total PEth, 3.7–10.4 days for PEth 16:0/18:1, 2.7–8.5 days for PEth 16:0/18:2 and 2.3–8.4 days for PEth 16:0/20:4.

Conclusions

The results demonstrated a very high sensitivity (100%) of PEth as alcohol biomarker for recent heavy drinking, but considerable differences in the elimination rates between individuals and between different PEth forms. This indicates that it is possible to make only approximate estimates of the quantity and recency of alcohol intake based on a single PEth value.

Vulnerable Periods: Characterizing Patterns of Sexual Risk and Substance Use During Lapses in Adherence to HIV Pre-exposure Prophylaxis Among Men Who Have Sex With Men

BACKGROUND

Pre-exposure prophylaxis (PrEP) is highly efficacious, but some groups of men who have sex with men may have difficulty adhering to daily dosing. Prevention-effective adherence suggests that PrEP's efficacy depends on adherence at the time of HIV exposure; yet, few studies have examined how exposures (ie, high-risk sex) overlap with periods of consecutive missed PrEP doses. Substance use may also play a role in these vulnerable periods.

METHODS

We used digital pill bottles to monitor the daily adherence of 40 PrEP-experienced patients recruited from an outpatient clinic in the Northeastern US over a six-month period. Participants also completed detailed online diaries every 2 weeks during this time that surveyed their sexual behavior and substance use each day.

RESULTS

Daily adherence was high overall (M = 83.9%, SD = 18.0%), but 53% (N = 21) had a lapse of > 3 consecutive daily PrEP doses over 6 months. Participants' rate of engaging in high-risk condomless anal sex (CAS) did not differ across lapse days versus continuously adherent days. Alcohol use was not associated with engaging in CAS during a PrEP lapse. However, participants reported engaging in CAS significantly more often during a PrEP adherence lapse on days when they also used stimulant drugs.

CONCLUSIONS

Men who have sex with men may have periodic difficulty adhering to PrEP at the specific times when they are at risk. Stimulant drug use could play an important role in increasing HIV risk specifically during adherence lapses.

Harmful alcohol use among acutely ill hospitalized medical patients in Oslo and Moscow: A cross-sectional study

BACKGROUND

The aim was to estimate the prevalence of harmful alcohol use in relation to socio-demographic characteristics among acutely ill medical patients, and examine identification measures of alcohol use, including the alcohol biomarker phosphatidylethanol 16:0/18:1 (PEth).

METHODS

A cross-sectional study, lasting one year at one hospital in Oslo, Norway and one in Moscow, Russia recruiting acute medically ill patients (≥ 18 years), able to give informed consent. Self-reported data on socio-demographics, mental distress (Symptom Check List-5), alcohol use (Alcohol Use Disorder Identification Test-4 (AUDIT-4) and alcohol consumption past 24 h were collected. PEth and alcohol concentration were measured in whole blood.

RESULTS

Of 5883 participating patients, 19.2% in Moscow and 21.1% in Oslo were harmful alcohol users, measured by AUDIT-4, while the prevalence of PEth-positive patients was lower: 11.4% in Oslo, 14.3% in Moscow. Men in Moscow were more likely to be harmful users by AUDIT-4 and PEth compared to men in Oslo, except of those being ≥ 71 years. Women in Oslo were more likely to be harmful users compared to those in Moscow by AUDIT-4, but not by PEth for those aged < 61 years.

CONCLUSIONS

The prevalence of harmful alcohol use was high at both study sites. The prevalence of harmful alcohol use was lower when assessed by PEth compared to AUDIT-4. Thus, self-reporting was the most sensitive measure in revealing harmful alcohol use among all groups except for women in Moscow. Hence, screening and identification with objective biomarkers and self-reporting might be a method for early intervention.

[Phospholipase D: its role in metabolism processes and disease development]

Phospholipase D (PLD) is one of the key enzymes that catalyzes the hydrolysis of cell membrane phospholipids. In this review current knowledge about six human PLD isoforms, their structure and role in physiological and pathological processes is summarized. Comparative analysis of PLD isoforms structure is presented. The mechanism of the hydrolysis and transphosphatidylation performed by PLD is described. The PLD1 and PLD2 role in the pathogenesis of some cancer, infectious, thrombotic and neurodegenerative diseases is analyzed. The prospects of PLD isoform-selective inhibitors development are shown in the context of the clinical usage and the already-existing inhibitors are characterized. Moreover, the formation of phosphatidylethanol (PEth), the alcohol abuse biomarker, as the result of PLD-catalyzed phospholipid transphosphatidylation is considered.

Screening for prenatal alcohol exposure and corresponding short-term neonatal outcomes

Detection of prenatal alcohol exposure (PAE) is important for early intervention and treatment. The main purpose of this study was to compare 1.) PAE rates using the biomarker, phosphatidylethanol (PEth), in umbilical cord (UC) blood vs. ethyl glucuronide (EtG) in UC tissue, the standard of care, and 2.) Pregnancy characteristics and neonatal outcomes in newborns positive vs. negative for PAE biomarkers. We examined records of neonates born over a two-year span receiving UC-PEth dried blood spots testing at the time of delivery in addition to standard of care PAE screening (n = 146). UC-PEth testing had a higher PAE detection rate (26%) vs. UC tissue EtG (0%, p < 0.01). PAE was not associated with any neonatal dysmorphic features or short-term adverse outcomes. The absence of significant clinical findings for identifying PAE in neonates reinforces alcohol biomarker necessity. We conclude that UC-PEth may be a valuable test for assessing PAE at birth and in identifying infants at risk for developing fetal alcohol spectrum disorder.

Use of alcohol biomarkers to identify alcohol misuse in organ donors

Phosphatidylethanol is a direct alcohol biomarker for identifying alcohol misuse. It carries several advantages over other alcohol biomarkers, including a detection half-life of several weeks and little confounding by patient characteristics or organ dysfunction. The aim of this study is to derive an optimal phosphatidylethanol cut point to identify organ donors with alcohol misuse, and to assess the impact of alcohol misuse on organ allocation. Discrimination of phosphatidylethanol was evaluated using the area under the ROC curve from a mixed effects logistic regression model. Phosphatidylethanol had an area under the ROC curve of 0.89 (95% CI 0.80-0.98). A phosphatidylethanol cut point of ≥84 ng/mL provided optimal discrimination for the identification of alcohol misuse with a sensitivity of 75% (95% CI 52.9%-89.4%) and a specificity of 97% (95% CI 91%-99%), a positive predictive value of 82% (95% CI 59%-94%), and a negative predictive value of 95% (95% CI 89%-98%). In deceased organ donors who had been critically ill, phosphatidylethanol had good test characteristics to discriminate alcohol misuse. Other alcohol biomarkers performed poorly in deceased organ donors. Liver allocation was decreased in donors with alcohol misuse by proxy history, but not in those with phosphatidylethanol >84 ng/mL, revealing possible information bias in liver allocation.

Determination of the formation rate of phosphatidylethanol by phospholipase D (PLD) in blood and test of two selective PLD inhibitors

Phosphatidylethanol (PEth) is an alcohol biomarker formed from phosphatidylcholine (PC) by the enzyme phospholipase D (PLD) in the presence of ethanol. A drinking study revealed individual differences in maximum PEth levels after drinking to a targeted blood alcohol concentration (BAC) of 0.1%. This seemed to be due to different PLD activities in the tested persons. Furthermore, post-sampling formation of PEth occurred in blood samples, still containing alcohol. Therefore, a standardized in vitro test for measuring individual PEth formation rates was developed. Two PLD inhibitors were tested for their potency to inhibit post-sampling PEth formation. PEth-negative blood samples were collected from a volunteer. Ethanol was added in different concentrations (0.01-0.3% BAC) directly after blood sampling. The specimens were incubated at 37 °C. Aliquots were taken at the start of the incubation, and every hour until 8 h after start of incubation, and one sample was taken on subsequent days over 1 week. PEth 16:0/18:1 and PEth 16:0/18:2 were determined by online SPE-LC-MS/MS. Furthermore, this test system was applied to blood samples of 12 volunteers. For the inhibition tests, fresh blood (spiked with 0.1% ethanol) was spiked with 30, 300, 3000, or 30,000 nM of either halopemide or 5-fluoro-2-indolyl-deschlorohalopemide (FIPI), and incubated at 37 °C. PEth concentrations were determined hourly over 5 h on the first day and once on day 2 and day 3. PEth formation was linear in the first 7 h of incubation and dependent on the alcohol concentration. The formation rates of PEth 16:0/18:1 were 0.002 μmol L^-1 h^-1 (0.01% BAC), 0.016 μmol L^-1 h^-1 (0.1% BAC), 0.025 μmol L^-1 h^-1 (0.2% BAC), and 0.029 μmol L^-1 h^-1 (0.3% BAC). For PEth 16:0/18:2, the formation rates were 0.002 μmol L^-1 h^-1 (0.01% BAC), 0.019 μmol L^-1 h^-1 (0.1% BAC), 0.025 μmol L^-1 h^-1 (0.2% BAC), and 0.030 μmol L^-1 h^-1 (0.3% BAC). Maximum concentrations reached 431 ng/mL (PEth 16:0/18:1) and 496 ng/mL (PEth 16:0/18:2) at 0.3% BAC after 3 days. Maximum velocity (v_max) was not reached under these conditions. PEth formation in blood of the 12 volunteers ranged between 0.011 and 0.025 μmol L^-1 h^-1 for PEth 16:0/18:1 and between 0.014 and 0.021 μmol L^-1 h^-1 for PEth 16:0/18:2. PEth formation in human blood was inhibited by halopemide in a concentration-dependent manner. However, a complete inhibition was not achieved by the applied maximum concentration of 30,000 nM. FIPI showed a better inhibition of PEth formation. A complete inhibition could be achieved by a concentration of 30,000 nM for the first 24 h (for PEth 16:0/18:1) and for 48 h (for PEth 16:0/18:2). Formation of PEth was found to be dependent on the BAC. As a consequence, it is essential to inhibit PLD activity after blood collection to avoid post-sampling formation of PEth in blood samples with a positive BAC. Inhibition of PEth formation was more effective using FIPI, compared to halopemide.

Pharmacokinetics of Phosphatidylethanol 16:0/20:4 in Human Blood After Alcohol Intake

BACKGROUND

The purpose of this study was to characterize the pharmacokinetics of the phosphatidylethanol (PEth) 16:0/20:4 homolog in uncoagulated human blood samples taken from 18 participants in a clinical laboratory setting after consumption of 2 standard doses of ethanol (EtOH).

METHODS

Male and female participants received either 0.4 or 0.8 g/kg oral doses of EtOH during a 15-minute period. Blood samples were collected before and throughout 6 hours immediately after alcohol administration and then again at days 2, 4, 7, 11, and 14 of the follow-up period. PEth 16:0/20:4 levels were quantified by high-performance liquid chromatography with tandem mass spectrometry detection.

RESULTS

(i) The increase in PEth 16:0/20:4 from baseline to maximum concentration was less than that of PEth 16:0/18:1 or PEth 16:0/18:2 homologs during the 6-hour period after EtOH administration; (ii) the mean half-life of PEth 16:0/20:4 was 2.1 ± 3 (SD) days, which was shorter than the mean half-life of either PEth 16:0/18:1 or PEth 16:0/18:2, 7.6 ± 3 (SD) or 6.8 ± 4 (SD) days, respectively.

CONCLUSIONS

The pharmacokinetics of PEth 16:0/20:4 in whole blood samples is detectable after alcohol consumption and differs in amount synthesized and rate of elimination versus PEth 16:0/18:1 and 16:0/18:2. Measuring the concentrations of these 3 homologs has the potential to provide more information about the amount and time frame of alcohol consumption than any one alone.

Differences in the Synthesis and Elimination of Phosphatidylethanol 16:0/18:1 and 16:0/18:2 After Acute Doses of Alcohol

BACKGROUND

The purpose of this study was to examine the synthesis and elimination of phosphatidylethanol (PEth) 16:0/18:1 and 16:0/18:2 following the consumption of alcohol among 56 light and heavy drinkers.

METHODS

A transdermal alcohol monitor was used to promote alcohol absence 7 days prior, and 14 days after, alcohol consumption in the laboratory. Participants consumed a 0.4 or 0.8 g/kg dose of alcohol in 15 minutes. Blood and breath samples were collected before, at various times up to 360 minutes postconsumption, and 2, 4, 7, 11, and 14 days after alcohol consumption. Initial rates of PEth synthesis, 360 minutes area under the PEth pharmacokinetic curves (AUCs), and elimination half-lives were determined.

RESULTS

(i) Nonzero PEth levels were observed before alcohol dosing for most participants, despite 7 days of alcohol use monitoring; (ii) 0.4 and 0.8 g/kg doses of alcohol produced proportional increases in PEth levels in all but 1 participant; (iii) the initial rate of synthesis of both PEth homologues did not differ between the 2 doses, but was greater for PEth 16:0/18:2 than PEth 16:0/18:1 at both doses; (iv) the mean AUC of both PEth homologues was higher at 0.8 g/kg than at 0.4 g/kg; (v) the mean AUC of 16:0/18:2 was greater than that of PEth 16:0/18:1 at both alcohol doses; (vi) the mean half-life of PEth 16:0/18:1 was longer than that of PEth 16:0/18:2 (7.8 ± 3.3 [SD] days and 6.4 ± 5.0 [SD] days, respectively); and (vii) there were no sex differences in PEth 16:0/18:1 or 16:0/18:2 pharmacokinetics.

CONCLUSIONS

The results of this study support the use of PEth 16:0/18:1 and 16:0/18:2 as biomarkers for alcohol consumption. Because of consistent pharmacokinetic differences, the levels of these 2 PEth homologues may provide more information regarding the quantity and recentness of alcohol consumption than either alone.

Phosphatidylethanol Levels Among Incarcerated Women: The Influence of Pre-incarceration Alcohol Consumption and Length of Abstinence

BACKGROUND

Phosphatidylethanol (PEth) is a direct biomarker for alcohol that is formed shortly after alcohol use and may remain detectable in blood for weeks after alcohol consumption. There is little research on alcohol use factors that influence PEth elimination, especially among women.

METHODS

Data were collected from 116 alcohol use-disordered women who were recently incarcerated. We used a 2-part model with logistic and linear components to examine whether alcohol consumption in the 2 weeks prior to incarceration and days since last alcoholic drink (operationalized as abstinence days prior to incarceration + days incarcerated) were associated with PEth detectability (>8 ng/ml) and level (ng/ml) in blood.

RESULTS

Participants reported drinking an average of 10 drinks per day in the 2 weeks prior to incarceration. Days since last drink was negatively associated with PEth level (odds ratio [OR] = 0.97, 95% confidence interval [CI] = 0.93; 0.99) and being PEth detectable (OR = 0.96, 95% CI = 0.91; 0.99). Quantity of alcohol consumed prior to jail admission was associated with PEth detection (OR = 1.08; 95% CI = 1.03; 1.16), but not PEth level.

CONCLUSIONS

Days since last alcoholic drink and drinks per day both influenced PEth detectability, but only days since last drink predicted PEth level among a large sample of women with alcohol use disorder in the criminal justice system.

[The comparative analysis of the methods for the determination of phosphatidylethanol in blood as a biological marker of alcohol abuse]

The confirmation of the fact of alcohol abuse is currently an important problem of both medical and social significance. Of all biological markers of alcohol consumption presently in use, blood phosphatidylethanol (PEth) is considered to be most sensitive and specific one. Therefore it has promising prospects for the further application. There is no universally accepted method for the calculation of the phosphatidylethanol concentration in human blood. For this reason, the present article places emphasis on the comparative characteristic of various methods for the determination of this substance.

Improving screening for alcohol consumption during pregnancy with phosphatidylethanol

OBJECTIVE

The study objective was to compare rates of alcohol use between urine ethanol testing and self- reporting (Method: 1) and Phosphatidylethanol (PEth) dried blood spot testing and self-reporting (Method: 2).

METHODS

This was a prospective observational study in an obstetric clinic with universal alcohol screening.

RESULTS

Method: 1 identified 11 patients with alcohol use (5 urine and 6 self-reported); Method: 2 identified 28 (22 PEth and 6 self-reported) out of 315 patients (one patient positive for both urine and PEth). The six patients with self-reported use had negative urine and PEth testing. We had fair agreement between the two methods (282 negative and 7 positive; 289/314=92.0%; Kappa 0.32, p<0.001); method 2 identified significantly more women (McNemar, p<0.001). Combining methods: resulted in an alcohol detection rate of 10.2% (32/314).

CONCLUSION

Method: 2 identified more alcohol users than Method: 1. Combining both methods: identified the most alcohol consumption.

Assessing phosphatidylethanol (PEth) levels reflecting different drinking habits in comparison to the alcohol use disorders identification test - C (AUDIT-C)

In addition to monitoring problematic or harmful alcohol consumption, drinking experiments indicated the potential of phosphatidylethanols (PEth) in abstinence monitoring. To date, no profound evaluation of thresholds for the differentiation of abstinence from moderate drinking and for detection of excessive consumption based on PEth homologues exists. Investigations with a large group of healthy volunteers (n=300) were performed to establish PEth reference values reflecting different drinking habits. Blood samples were analyzed for PEth 16:0/18:1 and 16:0/18:2 by online-SPE-LC-MS/MS method. Results were compared to AUDIT-C questionnaires, to the amounts of alcohol consumed during the two-weeks prior to blood sampling, and were statistically evaluated. PEth concentrations were significantly correlated with self-reported alcohol consumption (r>0.69) and with AUDIT-C scores (r>0.65). 4.0% of 300 volunteers reported abstinence (AUDIT-C score: 0), no PEth was detectable in their blood. PEth 16:0/18:1 concentrations below the limit of detection of 10.0ng/mL match with abstinence and light drinking habits (≤10g pure alcohol/day). However, some volunteers classified as "excessive alcohol consumers" had negative PEth results. In the group of volunteers classified as "moderate drinkers" (AUDIT-C score: 1-3 (women) and 1-4 (men)), 95% of the test persons had PEth 16:0/18:1 ranging from not detected to 112ng/mL, and PEth 16:0/18:2 ranging from not detected to 67.0ng/mL. Combination of self-reported alcohol consumption and AUDIT-C score showed that negative PEth results match with abstinence or light drinking. Moderate alcohol consumption resulted in PEth 16:0/18:1 from 0 to 112ng/mL and for PEth 16:0/18:2 ranged from 0 to 67.0ng/mL. Higher PEth concentrations indicated excessive alcohol consumption.

Identification and quantitation of phosphatidylethanols in oral fluid by liquid chromatography-tandem mass spectrometry

BACKGROUND

Phosphatidylethanols (PEth) are formed from phosphatidylcholines and ethanol and are used as a specific and sensitive alcohol biomarker. An analytical method for analysis of PEth in oral fluid based on high-performance liquid chromatography coupled to a quadrupole tandem mass spectrometer (LC-MS/MS) was developed and validated and applied on samples collected from patients undergoing alcohol detoxification.

METHODS

A 200-μL aliquot of oral fluid, collected using the QuantisalTM device, was extracted with chloroform/methanol containing internal standard and subjected to LC-MS/MS analysis of three selected PEth forms (16:0/16:0, 16:0/18:1, and 16:0/18:2). Chromatographic separation was achieved on a UPLC BEH phenyl column, using a mobile phase consisting of acetonitrile and water containing 10 mmol/L ammonium hydrogen carbonate with 0.1% ammonia. The MS instrument was operated in negative electrospray ionization and selected reaction monitoring mode.

RESULTS

The detection limit for PEth 16:0/16:0, 16:0/18:1, and 16:0/18:2 was ~0.1 ng/mL, and the extraction recoveries at 2.0 ng/mL were in the range of 99%-114%. Method linearity over a concentration range up to 200 ng/mL was ≥0.99. No significant deviation in results was observed in an analyte stability study of two different concentrations at two different temperatures over 3 months. In 35 oral fluid samples collected from patients undergoing alcohol detoxification, the highest concentration was observed for PEth 16:0/18:1 (Detected range, 0.51-55.3 ng/mL; mean, 8.5; median, 3.1). In addition, all three PEth forms were variably identified in a majority (63%) of the oral fluid samples. The PEth 16:0/18:1 values in oral fluid showed a weak positive correlation with the corresponding values in whole blood samples (r=0.50, p=0.026, n=20).

CONCLUSIONS

The LC-MS/MS method could reliably detect and quantify PEth in oral fluid samples collected after alcohol exposure. The method was characterized by validation data with satisfactory recovery, sensitivity, accuracy, and imprecision, and applied for analysis of clinical samples. The results suggest that measurement of PEth in oral fluid can be used as a biomarker for alcohol consumption, and as such a non-invasive complement to analysis in blood. However, further studies are required to evaluate the test characteristics (e.g. sensitivity and half-life) in comparison with PEth in blood.

Phosphatidylethanol (PEth) as a Biomarker of Alcohol Consumption in HIV-Infected Young Russian Women: Comparison to Self-Report Assessments of Alcohol Use

Alcohol use is particularly deleterious for HIV-infected individuals and thus accurate assessment of alcohol consumption is crucial in this population. Phosphatidylethanol (PEth) provides an objective assessment of drinking and can be compared to self-reported alcohol assessments to detect underreporting. The purpose of this study was to identify underreporting and its potential predictors in an HIV-infected sample of young Russian women. The current study examined the concordance between a quantitative measure of PEth and self-reported recent alcohol consumption in a prospective sample of HIV-infected young women (N = 204) receiving medical care in Saint Petersburg, Russia. At baseline, 53% of participants who denied drinking in the prior 30 days tested positive for PEth (i.e., underreporters), although this rate decreased significantly at a three-month follow-up assessment. Further exploration did not identify consistent predictors of underreporting status. Quantitative PEth levels showed, at best, modest overlap to self-reported alcohol consumption among those reporting alcohol use (e.g., Spearman's r = 0.27 between PEth and total drinks past-30 days at baseline). Objective measures of alcohol consumption demonstrate modest overlap with self-report measures of use in HIV-infected young Russian women. Incorporating objective and quantifiable biological markers are essential for valid assessments of alcohol use.

Biomarkers for the Detection of Prenatal Alcohol Exposure: A Review

Alcohol exposure during pregnancy can cause adverse effects to the fetus, because it interferes with fetal development, leading to later physical and mental impairment. The most common clinical tool to determine fetal alcohol exposure is maternal self-reporting. However, a more objective and useful method is based on the use of biomarkers in biological specimens alone or in combination with maternal self-reporting. This review reports on clinically relevant biomarkers for detection of prenatal alcohol exposure (PAE). A systematic search was performed to ensure a proper overview in existing literature. Studies were selected to give an overview on clinically relevant neonatal and maternal biomarkers. The direct biomarkers fatty acid ethyl esters (FAEEs), ethyl glucuronide (EtG), ethyl sulfate, and phosphatidylethanol (PEth) were found to be the most appropriate biomarkers in relation to detection of PAE. To review each biomarker in a clinical context, we have compared the advantages and disadvantages of each biomarker, in relation to its window of detectability, ease of collection, and the ease and cost of analysis of each biomarker. The biomarkers PEth, FAEEs, and EtG were found to be applicable for detection of even low levels of alcohol exposure. Meconium is an accessible matrix for determination of FAEEs and EtG, and blood an accessible matrix for determination of PEth.

Improved recovery of repeat intoxicated drivers using fingernails and blood spots to monitor alcohol and other substance abuse

OBJECTIVES

This study reports the results of a pilot program in Kenosha County that used a combination of direct biomarkers extracted from blood spots and nails to monitor repeat intoxicated drivers for their use of alcohol and drugs with a detection window spanning from 3 weeks to several months. The objectives were to test whether the direct biomarkers phosphatidylethanol (PEth), ethylglucuronide (EtG), and 5 drug metabolites would (1) help assessors obtain a more objective evaluation of repeat offenders during the assessment interview, (2) allow for timely identification of relapses and improve classification of drivers into risk categories, and (3) predict recidivism by identifying offenders most likely to obtain a subsequent operating while intoxicated (OWI) offense within 4 years of enrollment in the program.

METHODS

All (N = 261) repeat offenders were tested using PEth obtained from blood spots and EtG obtained from fingernails; 159 participants were also tested for a 5 drugs of abuse nail panel. Drivers were tested immediately after the assessment interview (baseline) and at 3, 6, 9, and 12 months after baseline. Based on biomarker results and self-reports of abstinence, offenders were classified into different risk categories and required to follow specific testing timelines based on the program's decision tree.

RESULTS

The baseline analysis shows that 60% of drivers tested positive for alcohol biomarkers (EtG, PEth, or both) at the assessment interview, with lower detection rates (0-11%) for the 5 drug metabolites. The comparison of biomarkers results to self-reports of abstinence identified 28% of all offenders as high risk and assigned them to more frequent testing and more intense monitoring. The longitudinal analysis shows that 56% (completers) of participants completed the program successfully and the remaining 44% (noncompliant) terminated prematurely. Two thirds (68%) of the completers were able to reduce or control their drinking and one third relapsed at least one time during their mandated monitoring periods. After a brief intervention by the assessors, 79% of relapsers tested negative for biomarkers in their repeat tests. The rearrest analysis showed that offenders classified in the noncompliant and relapsers groups were 7 times more likely to receive a new OWI 4 years after enrollment compared to drivers classified as abstainers or controllers. Refractory drivers were monitored the longest and reported no subsequent rearrests.

CONCLUSION

These findings demonstrate the benefits of more individualized interventions with repeat OWI offenders and calls for further development of multimodal approaches in traffic medicine including those that use direct alcohol biomarkers as evidence-based practices to reduce recidivism.

Nonoxidative ethanol metabolism in humans-from biomarkers to bioactive lipids

Ethanol is a widely used psychoactive drug whose chronic abuse is associated with organ dysfunction and disease. Although the prevalent metabolic fate of ethanol in the human body is oxidation a smaller fraction undergoes nonoxidative metabolism yielding ethyl glucuronide, ethyl sulfate, phosphatidylethanol and fatty acid ethyl esters. Nonoxidative ethanol metabolites persist in tissues and body fluids for much longer than ethanol itself and represent biomarkers for the assessment of ethanol intake in clinical and forensic settings. Of note, the nonoxidative reaction of ethanol with phospholipids and fatty acids yields bioactive compounds that affect cellular signaling pathways and organelle function and may contribute to ethanol toxicity. Thus, despite low quantitative contributions of nonoxidative pathways to overall ethanol metabolism the resultant ethanol metabolites have important biological implications. In this review we summarize the current knowledge about the enzymatic formation of nonoxidative ethanol metabolites in humans and discuss the implications of nonoxidative ethanol metabolites as biomarkers of ethanol intake and mediators of ethanol toxicity. © 2016 IUBMB Life, 68(12):916-923, 2016.