Role of variability in explaining ethanol pharmacokinetics: research and forensic applications

Endogenous ethanol production in health and disease

The gut microbiome exerts metabolic actions on distal tissues and organs outside the intestine, partly through microbial metabolites that diffuse into the circulation. The disruption of gut homeostasis results in changes to microbial metabolites, and more than half of the variance in the plasma metabolome can be explained by the gut microbiome. Ethanol is a major microbial metabolite that is produced in the intestine of nearly all individuals; however, elevated ethanol production is associated with pathological conditions such as metabolic dysfunction-associated steatotic liver disease and auto-brewery syndrome, in which the liver's capacity to metabolize ethanol is surpassed. In this Review, we describe the mechanisms underlying excessive ethanol production in the gut and the role of ethanol catabolism in mediating pathogenic effects of ethanol on the liver and host metabolism. We conclude by discussing approaches to target excessive ethanol production by gut bacteria.

Direct effects of alcohol on gut-epithelial barrier: Unraveling the disruption of physical and chemical barrier of the gut-epithelial barrier that compromises the host-microbiota interface upon alcohol exposure

The development of alcohol-associated diseases is multifactorial, mechanism of which involves metabolic alteration, dysregulated immune response, and a perturbed intestinal host-environment interface. Emerging evidence has pinpointed the critical role of the intestinal host-microbiota interaction in alcohol-induced injuries, suggesting its contribution to disease initiation and development. To maintain homeostasis in the gut, the intestinal mucosa serves as the first-line defense against exogenous factors in the gastrointestinal tract, including dietary contents and the commensal microbiota. The gut-epithelial barrier comprises a physical barrier lined with a single layer of intestinal epithelial cells and a chemical barrier with mucus trapping host regulatory factors and gut commensal bacteria. In this article, we review recent studies pertaining to the disrupted gut-epithelial barrier upon alcohol exposure and examine how alcohol and its metabolism can affect the regulatory ability of intestinal epithelium.

Relationship between alcohol intake based on daily smartphone-reported consumption and PEth concentrations in healthy volunteers

AIMS

To investigate the association between alcohol consumption registered daily with a digital smartphone-based diary and concentration of phosphatidylethanol (PEth) 16:0/18:1 in a population without a known alcohol use disorder (AUD), and evaluate whether prospective registration of alcohol consumption is better than retrospective registration and if the association between alcohol intake and PEth was affected by sex or body mass index (BMI).

METHODS

A total of 41 women and 21 men without AUD-diagnosis registered their alcohol consumption prospectively with a digital diary for 14 days, and retrospectively with the Timeline Followback method in the same time interval. PEth was measured before and after the registration period.

RESULTS

The correlation between alcohol consumption and PEth varied from 0.65 to 0.87. It did not depend significantly on the reporting method, and was not influenced by sex or BMI. Based on the regression coefficient, a reduction of alcohol consumption by two alcohol units (26 g of pure ethanol) per day would lead to a reduction of the PEth concentration of about 0.1 μmol/l, and vice versa.

CONCLUSIONS

There was a good correlation between PEth concentration and alcohol consumption, both when alcohol consumption was reported prospectively and retrospectively. The preferred cut-off for PEth should be adjusted to the level of alcohol consumption considered harmful and a purposeful trade-off between sensitivity and specificity. In order to identify persons with a daily alcohol consumption of more than two or three units of alcohol with a sensitivity of 80% or 90%, we suggest a cut-off of around 0.1 μmol/l.

Toxicological analysis in victims of sexual and domestic violence: A retrospective study of a 3-year period (2018-2020)

This manuscript presents an epidemiological investigation carried out on abuse victims who accessed the Sexual and Domestic Violence Service (SVS&D) of IRCCS Ca' Granda in Milan, Italy. The focal point of this research was the detection of alcohol, prescription medications, and illicit substances in victims who solicited help from the SVS&D center between 2018 and 2020. Over this three-year span, biological samples of blood and urine were procured from 207 victims, out of a patient pool of 2470. All collected samples were analyzed via High Performance Liquid Chromatography - Tandem Mass Spectrometry (HPLC-MS/MS) and Gas Chromatography - Mass Spectrometry (GC-MS). Toxicological examination results demonstrated that 43% of the cases tested positive for substances in 2018, 39% in 2019 and 60% of the cases in 2020. Overall, 45% of the victims tested resulted positive to some substance over a 3-year period, equivalent to 3.6% of the overall cases (2470 victims). Substances of toxicological interest were detected in 104 samples (out of 377, corresponding to 27.6%) belonging to 94 patients. The most detected classes of drugs were stimulants, antidepressants, benzodiazepines and antipsychotics. Moreover, BAC (Blood Alcohol Concentration) indicated positivity in 25 cases (out of 184 cases analyzed - 14% of positive cases). Based on this study's findings, we recommend broadening the range of substances evaluated in drug-facilitated sexual assaults and establishing standardized protocols for both national and international implementation. Implementing procedures would significantly enhance forensic support provided to victims of abuse seeking healthcare services post-incident.

Pharmacokinetic Analysis of Ethanol in a Human Study: New Modification of Mathematic Model

In the pharmacokinetic analysis of ethanol after oral administration, only single- or two-compartment models are used, but their precision in estimating pharmacokinetic parameters might be insufficient. In a recent study, pharmacokinetic analysis using a modified Norberg three-compartment model was performed after oral administration of differently sweetened alcoholic solutions and compared to pharmacokinetic analysis using the classic Widmark model. On three occasions, eight male volunteers consumed differently sweetened alcoholic solutions: non-sweetened, sweetened with sucrose, and sweetened with steviol glycoside. Blood ethanol concentration was determined from samples obtained at t = 15, 30, 60, 90, 120, 180 min after consumption. Pharmacokinetic analysis was performed model independently, using the classic Widmarks model and using the modified Norberg model. Results showed that estimated pharmacokinetic parameters depend on the type of model used. The classic Widmark model in particular overestimated the fraction of absorbed ethanol from the gastrointestinal system to systemic circulation. Furthermore, the type of sweetener also affected pharmacokinetic parameters, although the difference was not statistically significant. In conclusion, the novel pharmacokinetic model, while being more physiological, fits experimental data better and hence is more suitable for modelling real-life alcohol consumption. In addition, the effect of natural non-caloric sweetener steviol glycoside on ethanol pharmacokinetics, analysed for the first time in the current research, might be different when compared to the common-used sweetener sucrose.

Does polygenic risk for substance-related traits predict ages of onset and progression of symptoms?

BACKGROUND AND AIMS

Genetic risk can influence disease progression. We measured the impact of genetic risk for substance use disorders (SUDs) on substance use onset and progression of symptoms.

DESIGN, SETTING, PARTICIPANTS

Using findings from genome-wide association studies (GWASs) of alcohol use disorder (AUD), opioid use disorder (OUD) and smoking trajectory (SMK) as discovery samples, we calculated polygenic risk scores (PRSs) in a deeply phenotyped independent target sample. Participants in the target sample were recruited from 2000 to 2020 from US inpatient or outpatient settings or through advertisements and comprised 5692 European-ancestry individuals (EUR) (56.2% male) and 4918 African-ancestry individuals (AFR) (54.9% male).

MEASUREMENTS

This study measured age of first substance use, regular use, reported problems and dependence diagnosis and progression from regular use to onset of problems and dependence for alcohol, opioids and smoking. We examined the contribution of PRS to each milestone and progression measure.

FINDINGS

EUR and males reported an earlier onset and shorter progression times than AFR and females, respectively. Among EUR, higher AUD PRS predicted earlier onset and more rapid progression to alcohol-related milestones (P < 0.001). Although the AUD PRS was a stronger moderator of problem onset among females (P = 0.017), it was more predictive of the progression to problems among males (P = 0.005). OUD and SMK PRS in EUR also predicted earlier onset of the respective milestones (P < 0.001). Among AFR, where power is lower due to the smaller discovery sample, AUD PRS predicted age of regular alcohol use (P = 0.039) and dependence (P = 0.001) and progression from regular use to diagnosis (P = 0.045), while SMK PRS predicted earlier age of initiation (P = 0.036).

CONCLUSIONS

Genetic risk for SUDs appears to predict substance use milestones and symptom progression among European-ancestry individuals and, to a lesser extent, African-ancestry individuals.

The Associations of Auto-Brewery Syndrome and Diabetes Mellitus: A Literature Review and Clinical Perspective

Endogenous production of alcohol without the external intake of alcohol is called auto-brewery syndrome (ABS), and to get its levels to rise to a level that it has physical symptoms of alcohol intake is rare. The most common cause of ABS is the metabolism of ingested carbohydrates by intestinal microflora. This occurrence does not happen in all normal individuals but only in some high-risk individuals. Patients with diabetes mellitus (DM) have been hypothesized to be at high risk for ABS. We searched databases, such as PubMed, Medline, and PubMed Central, to search for existing literature with relevant keywords. In the finalized review, we have included 30 relevant articles. Alcohol formed in the gut gets absorbed in the bloodstream and immediately gets metabolized, so usually it does not achieve a level in blood high enough to cause symptoms. In high-risk patients, there is an increase in the level of bloodstream alcohol above a certain level, so it shows symptoms. Because there is higher blood glucose in DM, the patients have been shown to be at increased risk for developing ABS. Similarly, obesity is also a risk factor for DM, making it a high-risk condition for ABS. The most involved pathogens are Candida and Saccharomyces.

Fat-free mass accounts for most of the variance in alcohol elimination rate in women

BACKGROUND

Understanding how blood alcohol concentrations (BAC) achieved after drinking are determined is critical to predicting alcohol exposure to the brain and other organs and alcohol's effects. However, predicting end-organ exposures is challenging, as there is wide variation in BAC achieved after drinking a specified volume of alcohol. This variation is partly due to differences in body composition and alcohol elimination rates (AER), but there are limited data on how obesity affects AER. Here, we assess associations between obesity, fat-free mass (FFM), and AER in women and examine whether bariatric surgeries, which are linked to an increased risk of alcohol misuse, affect these associations.

METHODS

We analyzed data from three studies that used similar intravenous alcohol clamping procedures to estimate AER in 143 women (21 to 64 years old) with a wide range of body mass index (BMI; 18.5 to 48.4 kg/m2 ). Body composition was measured in a subgroup using dual-energy X-ray absorptiometry (n = 42) or Bioimpedance (n = 60), and 19 of the women underwent bariatric surgery 2.1 ± 0.3 years before participation. We analyzed data using multiple linear regression analyses.

RESULTS

Obesity and older age were associated with a faster AER (BMI: rs  = 0.70 and age: rs  = 0.61, both p < 0.001). Compared to women with normal weight, AER was 52% faster (95% Confidence Interval: 42% to 61%) in women with obesity. However, BMI lost predictive value when adding fat-free mass (FFM) to the regression model. Age, FFM, and its interaction explained 72% of individual variance in AER (F (4, 97) = 64.3, p < 0.001). AER was faster in women with higher FFM, particularly women in the top tertile of age. After controlling for FFM and age, bariatric surgery was not associated with differences in AER (p = 0.74).

CONCLUSIONS

Obesity is associated with a faster AER, but this association is mediated by an obesity-related increase in FFM, particularly in older women. Previous findings of a reduced alcohol clearance following bariatric surgery compared with prior to surgery are likely explained by a reduction in FFM post-surgery.

The effects of alcohol on testosterone synthesis in men: a review

INTRODUCTION

Testosterone concentrations in men decline with advancing age, with low testosterone concentrations being associated with multiple morbidities, an increased risk of early mortality, and a reduced quality of life. The purpose of this study was to examine the effects of alcohol on testosterone synthesis in men by investigating its effects on each level of the hypothalamic-pituitary-gonadal axis.

AREAS COVERED

Acute consumption of a low-to-moderate amount of alcohol increases testosterone concentrations in men, while consumption of a large volume of alcohol is associated with a reduction in serum testosterone concentrations. Elevated testosterone concentrations result from the increased activity of detoxification enzymes in the liver. Conversely, the primary mechanisms of action involved in the reduction of testosterone are increased hypothalamic-pituitary-adrenal axis activity, inflammation, and oxidative stress. When alcohol is consumed in excess, particularly chronically, it negatively affects testosterone production in men.

EXPERT OPINION

Since testosterone is an important component of men's health and wellbeing, current levels of alcohol consumption in many countries of the world require urgent attention. Elucidating the relationship between alcohol consumption and testosterone may be useful in identifying strategies to attenuate the testosterone-reducing effects of excessive or chronic alcohol consumption.

Ethanol Metabolism and Melanoma

Malignant melanoma is the deadliest form of skin cancer. Despite significant efforts in sun protection education, melanoma incidence is still rising globally, drawing attention to other socioenvironmental risk factors for melanoma. Ethanol and acetaldehyde (AcAH) are ubiquitous in our diets, medicines, alcoholic beverages, and the environment. In the liver, ethanol is primarily oxidized to AcAH, a toxic intermediate capable of inducing tumors by forming adducts with proteins and DNA. Once in the blood, ethanol and AcAH can reach the skin. Although, like the liver, the skin has metabolic mechanisms to detoxify ethanol and AcAH, the risk of ethanol/AcAH-associated skin diseases increases when the metabolic enzymes become dysfunctional in the skin. This review highlights the evidence linking cutaneous ethanol metabolism and melanoma. We summarize various sources of skin ethanol and AcAH and describe how the reduced activity of each alcohol metabolizing enzyme affects the sensitivity threshold to ethanol/AcAH toxicity. Data from the Gene Expression Omnibus database also show that three ethanol metabolizing enzymes (alcohol dehydrogenase 1B, P450 2E1, and catalase) and an AcAH metabolizing enzyme (aldehyde dehydrogenase 2) are significantly reduced in melanoma tissues.

Changes in Alcohol Consumption and Risk of Dementia in a Nationwide Cohort in South Korea

IMPORTANCE

The impact of serial changes in alcohol consumption on dementia risk has rarely been investigated to date.

OBJECTIVE

To investigate the association of comprehensive patterns of changes in alcohol consumption with the incidence of all-cause dementia, Alzheimer disease (AD), and vascular dementia (VaD).

DESIGN, SETTING, AND PARTICIPANTS

This is a retrospective cohort study. Data were obtained from the Korean National Health Insurance Service database. Adults aged 40 years and older underwent 2 health examinations in 2009 and 2011. The cohort was assessed until December 31, 2018, and statistical analysis was performed in December 2021.

EXPOSURES

Alcohol consumption level was categorized into none (0 g per day), mild (<15 g per day), moderate (15-29.9 g per day), and heavy (≥30 g per day) drinking. On the basis of changes in alcohol consumption level from 2009 to 2011, participants were categorized into the following groups: nondrinker, quitter, reducer, sustainer, and increaser.

MAIN OUTCOMES AND MEASURES

The primary outcome was newly diagnosed AD, VaD, or other dementia.

RESULTS

Among 3 933 382 participants (mean [SD] age, 55.0 [9.6] years; 2 037 948 men [51.8%]), during a mean (SD) follow-up of 6.3 (0.7) years, there were 100 282 cases of all-cause dementia, 79 982 cases of AD, and 11 085 cases of VaD. Compared with sustained nondrinking, sustained mild (adjusted hazard ratio [aHR], 0.79; 95% CI, 0.77-0.81) and moderate (aHR, 0.83; 95% CI, 0.79-0.88) drinking were associated with a decreased risk of all-cause dementia, whereas sustained heavy drinking was associated with an increased risk of all-cause dementia (aHR, 1.08; 95% CI, 1.03-1.12). Compared with sustained levels of drinking, reducing alcohol consumption from a heavy to a moderate level (aHR, 0.92; 95% CI, 0.86-0.99) and the initiation of mild alcohol consumption (aHR, 0.93; 95% CI, 0.90-0.96) were associated with a decreased risk of all-cause dementia. Increasers and quitters exhibited an increased risk of all-cause dementia compared with sustainers. The trends in AD and VaD remained consistent.

CONCLUSIONS AND RELEVANCE

In this cohort study of a Korean population, decreased risk of dementia was associated with maintaining mild to moderate alcohol consumption, reducing alcohol consumption from a heavy to a moderate level, and the initiation of mild alcohol consumption, suggesting that the threshold of alcohol consumption for dementia risk reduction is low.

Revisiting the Solubility-Permeability Relationship with Hydrophobic Drug Umifenovir in Pluronic Solutions: Impact of pH and Co-Solvent

This study describes the influence of pluronic F-127 (F-127) and ethanol (EtOH) on the solubility of umifenovir (UMF) in buffer solutions of pH 2.0 and pH 7.4, and its permeability through cellulose membranes. A 44.4-fold greater UMF solubility in acidic medium as compared to an alkaline one was estimated at 310.15 K. The concentration of UMF in the saturated solution was enhanced by the interaction with F-127 micelles. The combined positive effect of EtOH and F-127 on the solubility was estimated. The aggregation number of F-127 micelles in the presence of 10% and 20% ethanol appeared to be reduced by 2.1-fold and 4.1-fold, respectively, as compared to buffer pH 7.4. The presence of ethanol in buffer pH 7.4 solution provided better solvent conditions but inhibited the formation of F-127 micelles. The impact of UMF on the aggregation number of F-127 was not pronounced and was expressed only by a slight increase of 1 and 3 units in 10% and 20% EtOH, respectively. According to the values of zeta potential, addition of EtOH reduced the stability of the system. The permeation of UMF in buffer pH 7.4 measured through the cellulose membrane MWCO 12-14 kDa was increased 1.4-fold by 10% EtOH. An increase in EtOH content to 20% reduced this effect to 1.2-fold. Decreasing effect of 1.5% F-127 on the permeability was inhibited by using 10% EtOH. The solution containing 1.5% F-127 and 10% EtOH was shown to be an advantageous system for UMF in view of the solubility-permeability balance. The authors suppose the findings of the study to be useful for the design of pharmaceutical formulations based on UMF antiviral drugs.

P2X7 Receptor in Alcoholic Steatohepatitis and Alcoholic Liver Fibrosis

Alcoholic liver disease is one of the most common chronic liver diseases in the world. It is a liver disease caused by prolonged heavy drinking and its main clinical features are nausea, vomiting, enlargement of the liver, and jaundice. Recent studies suggest that Kupffer cell-mediated inflammatory response is a core driver in the development of alcoholic steatohepatitis and alcoholic liver fibrosis. As a danger signal, extracellular ATP activates the assembly of NLPR3 inflammasome by acting on purine P2X7 receptor, the activated NLRP3 inflammasome prompts ASC to cleave pro-cCaspase-1 into active caspase-1in KCs. Active caspase-1 promotes the conversion of pro-IL-1β to IL-1β, which further enhances the inflammatory response. Here, we briefly review the role of the P2X7R-NLRP3 inflammasome axis in the pathogenesis of alcoholic liver disease and the evolution of alcoholic steatohepatitis and alcoholic liver fibrosis. Regulation of the inflammasome axis of P2X7R-NLRP3 may be a new approach for the treatment of alcoholic liver disease.

Risk factors and protective factors for alcohol-related liver disease: A systematic review and meta-analysis

BACKGROUND

Although alcohol-related liver disease (ALD) is a global health threat, there are no specific effective treatments for it. Thus, efforts at preventing ALD are important and could be enhanced by using strategies based on validated risk and protective factors for the disease.

METHODS

The literature on factors influencing the risk for ALD was systematically searched from PubMed, Embase, and the Cochrane library databases from inception to June 2022. Factors suitable for quantitative analysis were submitted to meta-analysis using fixed-effects and random-effects models to calculate each factor's risk ratio (RR) and 95% confidence interval (CI).

RESULTS

Ten cohort studies (covering 1,005,339 subjects) that reported a clear causal relationship were included in the analysis, involving 11 potential risk factors (sex, race, education level, body mass index, alcohol consumption, types of alcoholic beverage, duration of drinking, drinking frequency, smoking, coffee consumption, and tea consumption). Three of these factors (sex, alcohol consumption, and smoking) were subjected to meta-analysis, and the results showed that male sex (RR = 2.84, 95% CI = 1.86-4.36), alcohol consumption ≥280 g/week (RR = 4.96, 95% CI = 2.71-9.07), and smoking (RR = 2.39, 95% CI = 1.97-2.89) were risk factors for ALD.

CONCLUSIONS

Many factors are likely to influence the incidence of ALD, and male sex, heavy alcohol consumption, and smoking increase the risk of ALD. The relationship between other factors and ALD risk needs further evaluation.

The neurobiological markers of acute alcohol's subjective effects in humans

The ingestion of alcohol yields acute biphasic subjective effects: stimulation before sedation. Despite their predictive relevance to the development of alcohol use disorders (AUD), the neurobiological markers accounting for the biphasic effects of alcohol remain poorly understood in humans. Informed by converging lines of evidence, this study tested the hypothesis that alcohol ingestion acutely increases gamma-aminobutyric acid (GABA)-mediated inhibition, which would positively and negatively predict the feeling of stimulation and sedation, respectively. To do so, healthy participants (n = 20) ingested a single dose of 94% ABV alcohol (males: 1.0 ml/kg; females: 0.85 ml/kg) in a randomized placebo-controlled cross-over design. The alcohol's biphasic effects were assessed with the Brief-Biphasic Alcohol Effects Scale, and non-invasive neurobiological markers were measured with transcranial magnetic stimulation, before and every 30 min (up to 120 min) after the complete ingestion of the beverage. Results showed that acute alcohol ingestion selectively increased the duration of the cortical silent period (CSP) as compared to placebo, suggesting that alcohol increases non-specific GABAergic inhibition. Importantly, CSP duration positively and negatively predicted increases in the feeling of stimulation and sedation, respectively, suggesting that stimulation emerges as GABAergic inhibition increases and that sedation emerges as GABAergic inhibition returns to baseline values. Overall, these results suggest that modulations of GABAergic inhibition are central to the acute biphasic subjective effects of alcohol, providing a potential preventive target to curb the progression of at-risk individuals to AUD.

What does current science tell us about the accuracy, reliability, and completeness of intoxicated witnesses? A case example of the murder of a prime minister

Generally, the testimony of intoxicated witnesses has been considered relatively unreliable, but recent research has nuanced the knowledge base regarding these vulnerable witnesses.

Alcohol-Related Liver Disease: An Overview on Pathophysiology, Diagnosis and Therapeutic Perspectives

Alcohol-related liver disease (ALD) refers to a spectrum of liver manifestations ranging from fatty liver diseases, steatohepatitis, and fibrosis/cirrhosis with chronic inflammation primarily due to excessive alcohol use. Currently, ALD is considered as one of the most prevalent causes of liver disease-associated mortality worldwide. Although the pathogenesis of ALD has been intensively investigated, the present understanding of its biomarkers in the context of early clinical diagnosis is not complete, and novel therapeutic targets that can significantly alleviate advanced forms of ALD are limited. While alcohol abstinence remains the primary therapeutic intervention for managing ALD, there are currently no approved medications for treating ALD. Furthermore, given the similarities and the differences between ALD and non-alcoholic fatty liver disease in terms of disease progression and underlying molecular mechanisms, numerous studies have demonstrated that many therapeutic interventions targeting several signaling pathways, including oxidative stress, inflammatory response, hormonal regulation, and hepatocyte death play a significant role in ALD treatment. Therefore, in this review, we summarized several key molecular targets and their modes of action in ALD progression. We also described the updated therapeutic options for ALD management with a particular emphasis on potentially novel signaling pathways.

Could Alcohol Abuse and Dependence on Junk Foods Inducing Obesity and/or Illicit Drug Use Represent Danger to Liver in Young People with Altered Psychological/Relational Spheres or Emotional Problems?

Recent data show that young people, mainly due to the pressure of some risk factors or due to disrupted interpersonal relationships, utilise greater reward value and display greater sensitivity to the reinforcing properties of “pleasurable stimuli”, specifically in those situations in which an enhanced dopamine release is present. Alcoholic beverages, foods rich in sugar and fat, and illicit drug use are pleasurable feelings associated with rewards. Research shows that there is a link between substance abuse and obesity in brain functioning. Still, alcohol excess is central in leading to obesity and obesity-related morbidities, such as hepatic steatosis, mainly when associated with illicit drug dependence and negative eating behaviours in young people. It is ascertained that long-term drinking causes mental damage, similarly to drug abuse, but also affects liver function. Indeed, beyond the pharmacokinetic interactions of alcohol with drugs, occurring in the liver due to the same metabolic enzymes, there are also pharmacodynamic interactions of both substances in the CNS. To complicate matters, an important noxious effect of junk foods consists of inducing obesity and obesity-related NAFLD. In this review, we focus on some key mechanisms underlying the impact of these addictions on the liver, as well as those on the CNS.

Gut microbiota and voluntary alcohol consumption

Alcohol is part of the usual diet of millions of individuals worldwide. However, not all individuals who drink alcohol experience the same effects, nor will everyone develop an alcohol use disorder. Here we propose that the intestinal microbiota (IMB) helps explain the different consumption patterns of alcohol among individuals. 507 humans participated in this study and alcohol consumption and IMB composition were analyzed. On the other hand, in 80 adult male Wistar rats, behavioral tests, alcohol intoxication, fecal transplantation, administration of antibiotics and collection of fecal samples were performed. For identification and relative quantification of bacterial taxa was used the bacterial 16 S ribosomal RNA gene. In humans, we found that heavy episodic drinking is associated with a specific stool type phenotype (type 1, according to Bristol Stool Scale; p < 0.05) and with an increase in the abundance of Actinobacteria (p < 0.05). Next, using rats, we demonstrate that the transfer of IMB from alcohol-intoxicated animals causes an increase in voluntary alcohol consumption in transplant-recipient animals (p < 0.001). The relative quantification data indicate that the genus Porphyromonas could be associated with the effect on voluntary alcohol consumption. We also show that gut microbiota depletion by antibiotics administration causes a reduction in alcohol consumption (p < 0.001) and altered the relative abundance of relevant phyla such as Firmicutes, Bacteroidetes or Cyanobacteria (p < 0.05), among others. Benjamini-Hochberg false discovery rate (FDR) correction was performed for multiple comparisons. These studies reveal some of the consequences of alcohol on the IMB and provide evidence that manipulation of IMB may alter voluntary alcohol consumption.

Principles of dose-setting in toxicology studies: the importance of kinetics for ensuring human safety

Regulatory toxicology seeks to ensure that exposures to chemicals encountered in the environment, in the workplace, or in products pose no significant hazards and produce no harm to humans or other organisms, i.e., that chemicals are used safely. The most practical and direct means of ensuring that hazards and harms are avoided is to identify the doses and conditions under which chemical toxicity does not occur so that chemical concentrations and exposures can be appropriately limited. Modern advancements in pharmacology and toxicology have revealed that the rates and mechanisms by which organisms absorb, distribute, metabolize and eliminate chemicals-i.e., the field of kinetics-often determine the doses and conditions under which hazard, and harm, are absent, i.e., the safe dose range. Since kinetics, like chemical hazard and toxicity, are extensive properties that depend on the amount of the chemical encountered, it is possible to identify the maximum dose under which organisms can efficiently metabolize and eliminate the chemicals to which they are exposed, a dose that has been referred to as the kinetic maximum dose, or KMD. This review explains the rationale that compels regulatory toxicology to embrace the advancements made possible by kinetics, why understanding the kinetic relationship between the blood level produced and the administered dose of a chemical is essential for identifying the safe dose range, and why dose-setting in regulatory toxicology studies should be informed by estimates of the KMD rather than rely on the flawed concept of maximum-tolerated toxic dose, or MTD.

Current View on the Mechanisms of Alcohol-Mediated Toxicity

Alcohol is a psychoactive substance that is widely used and, unfortunately, often abused. In addition to acute effects such as intoxication, it may cause many chronic pathological conditions. Some of the effects are very well described and explained, but there are still gaps in the explanation of empirically co-founded dysfunction in many alcohol-related conditions. This work focuses on reviewing actual knowledge about the toxic effects of ethanol and its degradation products.

Integration of a physiologically-based pharmacokinetic model with a whole-body, organ-resolved genome-scale model for characterization of ethanol and acetaldehyde metabolism

Ethanol is one of the most widely used recreational substances in the world and due to its ubiquitous use, ethanol abuse has been the cause of over 3.3 million deaths each year. In addition to its effects, ethanol's primary metabolite, acetaldehyde, is a carcinogen that can cause symptoms of facial flushing, headaches, and nausea. How strongly ethanol or acetaldehyde affects an individual depends highly on the genetic polymorphisms of certain genes. In particular, the genetic polymorphisms of mitochondrial aldehyde dehydrogenase, ALDH2, play a large role in the metabolism of acetaldehyde. Thus, it is important to characterize how genetic variations can lead to different exposures and responses to ethanol and acetaldehyde. While the pharmacokinetics of ethanol metabolism through alcohol dehydrogenase have been thoroughly explored in previous studies, in this paper, we combined a base physiologically-based pharmacokinetic (PBPK) model with a whole-body genome-scale model (WBM) to gain further insight into the effect of other less explored processes and genetic variations on ethanol metabolism. This combined model was fit to clinical data and used to show the effect of alcohol concentrations, organ damage, ALDH2 enzyme polymorphisms, and ALDH2-inhibiting drug disulfiram on ethanol and acetaldehyde exposure. Through estimating the reaction rates of auxiliary processes with dynamic Flux Balance Analysis, The PBPK-WBM was able to navigate around a lack of kinetic constants traditionally associated with PK modelling and demonstrate the compensatory effects of the body in response to decreased liver enzyme expression. Additionally, the model demonstrated that acetaldehyde exposure increased with higher dosages of disulfiram and decreased ALDH2 efficiency, and that moderate consumption rates of ethanol could lead to unexpected accumulations in acetaldehyde. This modelling framework combines the comprehensive steady-state analyses from genome-scale models with the dynamics of traditional PK models to create a highly personalized form of PBPK modelling that can push the boundaries of precision medicine.

Hip-flask defense: An experimental study in the Hungarian population

Toxicology tests and medical expert opinions are part of routine work in drunk driving cases in both domestic and international practice. The greatest challenge to forming an opinion is that the perpetrator claims to have consumed alcohol after the act of driving. To determine the time of consumption, it is essential to establish whether the alcohol in the body was in the absorption phase or in the elimination phase when the sample was collected. In domestic practice, breath alcohol content can be measured several times, two blood samples can be collected, and both blood and urine samples can be taken almost simultaneously. A recent Swedish study showed that taking a single blood sample and two urine samples allows for a more accurate examination of consumption after the fact. This study aimed to examine the applicability of such model to the domestic environment. We conducted a controlled drinking experiment involving 15 Hungarian casual drinker volunteers aged 18-25 years who consumed different amounts of alcohol at specified times while providing regular breath alcohol measurements as well as blood and urine samples. These measurement results provided accurate information about the changes in alcohol metabolism compared to the time of drinking and allowed us to draw the necessary conclusions, offering further evidence that alcohol metabolism can vary significantly between different ethnic groups. The results showed that the absorption and excretion of ethyl alcohol in the volunteers were much faster than those in the current Hungarian standards used in practice. In conclusion, the comparison of blood and urine samples collected between 60 min and 120 min cannot be considered suitable for establishing the fact of drinking after driving in Hungarian practice, and a local model is needed.

Effects of stomach content on the breath alcohol concentration-transdermal alcohol concentration relationship

INTRODUCTION

Wearable devices that obtain transdermal alcohol concentration (TAC) could become valuable research tools for monitoring alcohol consumption levels in naturalistic environments if the TAC they produce could be converted into quantitatively-meaningful estimates of breath alcohol concentration (eBrAC). Our team has developed mathematical models to produce eBrAC from TAC, but it is not yet clear how a variety of factors affect the accuracy of the models. Stomach content is one factor that is known to affect breath alcohol concentration (BrAC), but its effect on the BrAC-TAC relationship has not yet been studied.

METHODS

We examine the BrAC-TAC relationship by having two investigators participate in four laboratory drinking sessions with varied stomach content conditions: (i) no meal, (ii) half and (iii) full meal before drinking, and (iv) full meal after drinking. BrAC and TAC were obtained every 10 min over the BrAC curve.

RESULTS

Eating before drinking lowered BrAC and TAC levels, with greater variability in TAC across person-device pairings, but the BrAC-TAC relationship was not consistently altered by stomach content. The mathematical model calibration parameters, fit indices, and eBrAC curves and summary score outputs did not consistently vary based on stomach content, indicating that our models were able to produce eBrAC from TAC with similar accuracy despite variations in the shape and magnitude of the BrAC curves under different conditions.

DISCUSSION AND CONCLUSIONS

This study represents the first examination of how stomach content affects our ability to model estimates of BrAC from TAC and indicates it is not a major factor.

The Relationship Between Ingested Dose of Ethanol and Amount of Ethyl Glucuronide Formed in Blood

A positive non-linear relation between the dose of ethanol ingested and the area under the curve (AUC) for ethyl glucuronide (EtG) in urine is previously observed. The relation between both doses and AUC of ethanol and the AUC for EtG in blood is not previously published, and this study aimed to investigate this relationship. After an overnight fast, 10 healthy volunteers ingested 0.5-g ethanol per kilo body weight (low dose) in one occasion and 1.0-g ethanol per kilo body weight (high dose) in the next occasion. Results showed that there was a significant higher median ratio between blood AUC for EtG and dose of ethanol in the high-dose (8.99; range 7.37–10.94) group compared to the low-dose (5.02; range 4.25–6.15) group (P = 0.005). The median ratio between the AUC for EtG and AUC for ethanol was actually significantly higher in the low-dose (1.77; range 1.51–2.24) group compared to the high-dose (1.67; range 1.30–2.02) group (P = 0.005), although values are quite similar. This study therefore showed that the ratio between the AUC for EtG in blood and dose of ethanol is higher after intake of 1.0 g/kg than 0.5 g/kg. This pattern is however not seen when AUC for EtG is compared to AUC for ethanol. Results therefore support that the percentage of ethanol converted to EtG is not increasing when the doses increase. An explanation for the positive non-linear relation previously observed between the dose of ethanol ingested and amount of EtG formed may be a relative higher first-pass metabolism of ethanol at lower doses.

Accelerated ethanol elimination via the lungs

Ethanol poisoning is endemic the world over. Morbidity and mortality depend on blood ethanol levels which in turn depend on the balance between its rates of absorption and clearance. Clearance of ethanol is mostly at a constant rate via enzymatic metabolism. We hypothesized that isocapnic hyperpnea (IH), previously shown to be effective in acceleration of clearance of vapour anesthetics and carbon monoxide, would also accelerate the clearance of ethanol. In this proof-of-concept pilot study, five healthy male subjects were brought to a mildly elevated blood ethanol concentration (~ 0.1%) and ethanol clearance monitored during normal ventilation and IH on different days. IH increased elimination rate of ethanol in proportion to blood levels, increasing the elimination rate more than three-fold. Increased veno-arterial ethanol concentration differences during IH verified the efficacy of ethanol clearance via the lung. These data indicate that IH is a nonpharmacologic means to accelerate the elimination of ethanol by superimposing first order elimination kinetics on underlying zero order liver metabolism. Such kinetics may prove useful in treating acute severe ethanol intoxication.

The Feasibility, Tolerability, and Safety of Administering a Very High Alcohol Dose to Drinkers with Alcohol Use Disorder

INTRODUCTION

There remains a paucity of research quantifying alcohol's effects in drinkers with alcohol use disorder (AUD), particularly responses to very high alcohol doses (≥0.8 g/kg). As drinkers with AUD frequently engage in very heavy drinking (8 to 10 drinks/occasion), doses of ≤0.8 g/kg may lack ecological validity. The present study examined the feasibility, tolerability, and safety of administering a very high alcohol dose (1.2 g/kg) to non-treatment-seeking AUD participants.

METHODS

Sixty-one young adult AUD drinkers enrolled in the Chicago Social Drinking Project and completed 3 laboratory sessions at which they consumed a beverage with 1.2, 0.8, and 0.0 g/kg alcohol. Physiological responses (vital signs, nausea and vomiting, breath alcohol concentrations [BrAC]) were monitored throughout the sessions. After each session, participants completed a next-day survey of substance use, engagement in risky behaviors, and related consequences.

RESULTS

Overall, the sample demonstrated good compliance with study procedures; 93% of participants adhered to presession alcohol abstinence requirements (indicated by BrAC < 0.003 g/dl), with no participants exhibiting serious alcohol withdrawal symptoms at arrival to study visits. The 1.2 g/kg alcohol dose achieved an expected mean peak BrAC of 0.13 g/dl at 60 minutes after drinking, which was well tolerated; the majority of the sample did not experience nausea (70%) or vomiting (93%), and dose effects on vital signs were not clinically significant. Finally, we demonstrated that the 1.2 g/kg alcohol dose is safe and not associated with postsession consequences, including reduced sleep time, atypical substance use, accidents or injuries, and severe hangovers.

CONCLUSION

Results support the feasibility, tolerability, and safety of administering a very high alcohol dose to young adult drinkers with AUD within the context of a well-validated laboratory alcohol challenge paradigm. Utilizing an alcohol dose more consistent with naturalistic drinking patterns may foster greater ecological validity of laboratory paradigms for persons with moderate to severe AUD.

Evaluating the hip-flask defence using analytical data from ethanol and ethyl glucuronide. A comparison of two models

AIM

Claimed intake of alcohol after a traffic incident, called the hip-flask defence, can be objectively assessed by different methods. One of them is the use of two consecutive ethanol concentrations in urine and the ratio between ethanol concentrations in urine and blood. Another one is the concentrations of ethyl glucuronide (EtG) and ethyl sulphate (EtS) in blood and their ratio to ethanol. The experimental basis for both these models is from single dose studies only. The aim of this study was therefore to describe the kinetics of ethanol, EtG and EtS after ingestion of two repeated doses of ethanol and to investigate the usefulness of the different models for the assessment of the hip-flask defence.

METHODS

Thirty-five subjects ingested a first dose of 0.51 g of ethanol per kilo body weight, and two hours later a second dose (the hip-flask drink) of 0.25, 0.51 or 0.85 g of ethanol per kilo body weight. Ten urine and 17 blood samples were collected and analysed for ethanol, EtG and EtS using fully validated methods. It was investigated if all subjects fulfilled the criteria for recent drinking, according to the two different models, when using the samples collected 180-240 minutes after start of first dose drinking. According to the first model, increase in urinary ethanol concentrations and a ratio UAC/BAC below 1.3 indicated recent drinking. According to the second model, increase in blood EtG concentrations and a ratio ethanol (g/kg)/EtG (mg/L) above 1 indicated recent drinking.

RESULTS

All subjects in the high dose group fulfilled all criteria for recent drinking. One subject in the medium dose group and nine subjects in the low dose group failed to show increasing UAC and/or a UAC/BAC ratio below 1.3. One subject in the low dose group failed to show increasing concentrations of blood EtG, but all subjects showed a ratio ethanol/EtG above 1.

CONCLUSIONS

The present study showed, by the use of experimental data, that both two models used to investigate the hip-flask defence can be used, but only when the hip-flask dose is sufficiently high.

The impact of total body water on breath alcohol calculations

Due to a legislative amendment in Austria to determine breath alcohol (BrAC) instead of blood alcohol (BAC) in connection with traffic offences, many results of blood alcohol calculations were simply converted using distinct conversion factors. In Austria, the transformation of BAC to BrAC was carried out by using a factor of 1:2000, which, however, is commonly known to be too low. Noticing the great demand for a calculation method that is not exclusively based on blood alcohol, a formula for calculating breath alcohol based on blood alcohol was published in 1989, but in which the body surface area (BSA) was considered the most important influencing variable. In order to refine this new method, a liquor intake experiment was conducted combined with measurements of total body water (TBW) as an additional variable, using hand to foot bioelectrical impedance assessment (BIA). The test group comprised 37 men and 40 women to evaluate the accuracy of TBW and BSA as an individual parameter for alcohol concentration. The correlation coefficient of BrAC with TBW was constantly higher than with BSA (maximum = 0.921 at 1 h and 45 min after cessation of alcohol intake). These results are valid for both men and women as well as in a gender independent calculation. Hence, for an accurate back calculation of BrAC adjusted values of eliminations rates had to be found. This study describes mean elimination rates of BrAC for both men (0.065 ± 0.011 mg/L h⁻¹) and women (0.074 ± 0.017 mg/L h⁻¹). As previously shown women displayed a significantly higher elimination rate than men (p = 0.006).

Liver regeneration and alcoholic liver disease

Alcoholic liver diseases (ALD) are a wide spectrum of liver diseases caused by excessive alcohol consumption, from steatosis to cirrhosis. The pathogenesis of ALD is insufficiently understood, but mainly involves oxidative stress, inflammation, bacterial translocation, cell death, and impaired regeneration. Despite numerous attempts to improve patient prognosis, the treatment of advanced ALD is still based on abstinence, brief exposure to corticosteroids, or liver transplantation. However, poor response to corticosteroids and the shortage of liver donors leaves patients helpless towards the end stages. Advances in basic research have contributed to a better understanding of ALD pathophysiology, which offers new options for treatment. In recent years, several therapies related to liver regeneration have been tested with promising prospects, including molecule-induced liver regeneration, stem cell transplantation, and full-function 3D artificial liver assembly. This review discusses mechanisms underlying ALD that can be considered therapeutic targets for regeneration-based treatments.

Gut microbiota in non-alcoholic fatty liver disease and alcohol-related liver disease: Current concepts and perspectives

The term, gut-liver axis, is used to highlight the close anatomical and functional relationship between the intestine and the liver. It has been increasingly recognized that the gut-liver axis plays an essential role in the development and progression of liver disease. In particular, in non-alcoholic fatty liver disease and alcohol-related liver disease, the two most common causes of chronic liver disease, a dysbiotic gut microbiota can influence intestinal permeability, allowing some pathogens or bacteria-derived factors from the gut reaching the liver through the enterohepatic circulation contributing to liver injury, steatohepatitis, and fibrosis progression. Pathways involved are multiple, including changes in bile acid metabolism, intestinal ethanol production, generation of short-chain fatty acids, and other by-products. Bile acids act through dedicated bile acid receptors, farnesoid X receptor and TGR5, in both the ileum and the liver, influencing lipid metabolism, inflammation, and fibrogenesis. Currently, both non-alcoholic fatty liver disease and alcohol-related liver disease lack effective therapies, and therapeutic targeting of gut microbiota and bile acids enterohepatic circulation holds promise. In this review, we summarize current knowledge about the role of gut microbiota in the pathogenesis of non-alcoholic fatty liver disease and alcohol-related liver disease, as well as the relevance of microbiota or bile acid-based approaches in the management of those liver diseases.

Alcohol and Dementia - What is the Link? A Systematic Review

BACKGROUND

Dementia is a globally increasing health issue and since no cure is currently available, prevention is crucial. The consumption of alcohol is a controversially discussed risk factor for dementia. While many previously published epidemiological studies reported a risk reduction by light to moderate alcohol consumption, there is no persuasive model of an underlying biochemical mechanism. The purpose of this article is to review current models on alcohol neurotoxicity and dementia and to analyze and compare studies focusing on the epidemiological link between alcohol consumption and the risk of dementia.

METHODS

The electronic database Pubmed was searched for studies published between 1994 and 2019 concerning the topic.

RESULTS

Available epidemiological studies are not sufficient to verify a protective effect of alcohol on dementia development.

Body mass index modifies the association between frequency of alcohol consumption and incidence of hypertension in men but not in women: a retrospective cohort study

Alcohol consumption is one of the major modifiable risk factors of hypertension. The aim of the present retrospective study was to assess the clinical impact of obesity on the association between alcohol consumption and the incidence of hypertension. The present study included 5116 male and 6077 female university employees with a median age of 32 (interquartile range 27-39) who underwent annual health checkups between January 2005 and March 2013. Self-reported drinking frequency was recorded at their first checkup and categorized into rarely and 1-3, 4-6, and 7 days/week. During the median observational period of 4.9 years (interquartile range 2.1-8.3), hypertension, defined as systolic/diastolic blood pressure of ≥140/90 mmHg and/or self-reported treatment for hypertension, was observed in 1067 (20.9%) men and 384 (6.3%) women. Poisson regression models adjusted for clinically relevant factors revealed a dose-dependent association between drinking frequency and the incidence of hypertension in men (adjusted incidence rate ratio [95% confidence interval] of men who drank rarely, 1-3, 4-6, and 7 days/week was 1.00 [reference], 1.12 [0.97-1.30], 1.42 [1.19-1.70], and 1.35 [1.14-1.59], respectively; P_trend < 0.001). However, this association was not observed in women. The dose-dependent association was significant in nonobese men (body mass index (BMI) < 25 kg/m²), but not in obese men (BMI ≥25 kg/m²) (P for interaction between drinking frequency and BMI = 0.072). The present study provides clinically useful evidence to identify the drinkers who may reap the health benefits of abstinence from alcohol consumption.

The causal web of foetal alcohol spectrum disorders: a review and causal diagram

Foetal alcohol spectrum disorders (FASDs) are a leading cause of developmental disability. Prenatal alcohol use is the sole necessary cause of FASD, but it is not always sufficient. Multiple factors influence a child's susceptibility to FASD following prenatal alcohol exposure. Much of the FASD risk factor literature has been limited to discussions of association, rather than causation. While knowledge of predictor variables is important for identifying who is most at risk of FASD and for targeting interventions, causal knowledge is important for identifying effective mechanisms for prevention and intervention programmes. We conducted a systematic search and narrative synthesis of the evidence and used this to create a causal diagram (directed acyclic graph; DAG) to describe the causal pathways to FASD. Our results show that the aetiology of FASD is multifaceted and complex. FASD risk is determined by a range of lifestyle, sociodemographic, maternal, social, gestational, and genetic factors. The causal diagram that we present in this review provides a comprehensive summary of causal risk factors for FASD and can be used as a tool to inform data collection and statistical modelling strategies to minimise bias in future studies of FASD.

Ethanol Intoxication of Young Children

Ethanol intoxication of infants and young children can be a challenging diagnosis in the pediatric emergency department, and features of the poisoning may differ in comparison with adolescents. The sources of ethanol exposures in this age are varied and include unintentional, malicious, and iatrogenic etiologies. Young children exposed to ethanol often present with mixed clinical signs and symptoms that may not fit the traditional ethanol or sedative-hypnotic toxidrome. Pediatric ethanol intoxications are often managed supportively, and recovery is usually rapid. The purpose of this review is to describe the sources of ethanol poisoning among children 6 years and younger, highlight presenting symptoms and pharmacokinetic considerations unique to this age group, and review management strategies. In addition, published cases of ethanol poisoning due to ingestion among young infants are compiled for presentation.

Natural compounds in the chemoprevention of alcoholic liver disease

Alcoholic liver disease (ALD), caused by excessive consumption of alcohol, is a major cause of chronic liver disease worldwide. Much effort has been expended to explore the pathogenesis of ALD. Hepatic cell injury, oxidative stress, inflammation, regeneration, and bacterial translocation are all involved in the pathogenesis of ALD. Immediate abstinence is the most important therapeutic treatment for affected individuals. However, the medical treatment for ALD had not advanced in a long period. Intriguingly, an increasing body of research indicates the potential of natural compounds in the targeted therapy of ALD. A plethora of dietary natural products such as flavonoids, resveratrol, saponins, and β-carotene are found to exert protective effects on ALD. This occurs through various mechanisms composed of antioxidative, anti-inflammatory, iron chelation, pro-apoptosis, and/or antiproliferation of hepatic stellate cells and hepatocellular carcinoma cells. In this review, we will summarize current knowledge about the pathogenesis and treatments of ALD and focus on the potential of natural compounds in ALD therapies and underlying mechanisms.

Oxidative stress and DNA damage in the mechanism of fetal alcohol spectrum disorders

This review covers molecular mechanisms involving oxidative stress and DNA damage that may contribute to morphological and functional developmental disorders in animal models resulting from exposure to alcohol (ethanol, EtOH) in utero or in embryo culture. Components covered include: (a) a brief overview of EtOH metabolism and embryopathic mechanisms other than oxidative stress; (b) mechanisms within the embryo and fetal brain by which EtOH increases the formation of reactive oxygen species (ROS); (c) critical embryonic/fetal antioxidative enzymes and substrates that detoxify ROS; (d) mechanisms by which ROS can alter development, including ROS-mediated signal transduction and oxidative DNA damage, the latter of which leads to pathogenic genetic (mutations) and epigenetic changes; (e) pathways of DNA repair that mitigate the pathogenic effects of DNA damage; (f) related indirect mechanisms by which EtOH enhances risk, for example by enhancing the degradation of some DNA repair proteins; and, (g) embryonic/fetal pathways like NRF2 that regulate the levels of many of the above components. Particular attention is paid to studies in which chemical and/or genetic manipulation of the above mechanisms has been shown to alter the ability of EtOH to adversely affect development. Alterations in the above components are also discussed in terms of: (a) individual embryonic and fetal determinants of risk and (b) potential risk biomarkers and mitigating strategies. FASD risk is likely increased in progeny which/who are biochemically predisposed via genetic and/or environmental mechanisms, including enhanced pathways for ROS formation and/or deficient pathways for ROS detoxification or DNA repair.

Lower Blood Alcohol Concentration Among HIV-Positive Versus HIV-Negative Individuals Following Controlled Alcohol Administration

BACKGROUND

Although it has been purported that HIV-positive individuals may experience a greater degree of intoxication than HIV-negative individuals following acute alcohol consumption, no research to date has empirically tested this supposition. The present investigation entailed a randomized controlled experiment to identify whether the administration of a weight-specified dose of alcohol would lead to differential blood alcohol concentrations (BACs) among HIV-positive versus HIV-negative men.

METHODS

In a specialized barroom laboratory, 143 men (n = 76 HIV-positive and n = 67 HIV-negative; mean age = 42.9) consumed beverages based on a formulation of 0.7 g alcohol/kg body weight over a 15-minute time frame. BAC was assessed via breathalyzer at 2 set time points (10 and 13 minutes postconsumption) and then periodically until detoxification (BAC < 0.040%). Primary outcomes included (i) area under the curve (AUC), calculated based on all of one's BAC readings, (ii) "BAC-EXP," defined as one's BAC reading 13 minutes postconsumption, and (iii) BAC-PEAK, defined as one's highest recorded BAC reading.

RESULTS

Contrary to predictions, AUC (t(141) = 2.23, p = 0.027), BAC-EXP (t(141) = 2.68, p = 0.008), and BAC-PEAK (t(141) = 2.29, p = 0.023) were significantly lower among HIV-positive versus HIV-negative participants. These effects were sustained in multivariable models controlling for age, race, and AUDIT-based hazardous drinking classification. Among the HIV-positive sample, outcomes did not significantly differ based on HIV viral load detectability, antiretroviral therapy (ART) status, or ART adherence.

CONCLUSIONS

The administration of a controlled, weight-specified dose of alcohol led to lower BACs among HIV-positive versus HIV-negative participants. These differences might derive from decreased body fat percentage and delayed gastric emptying associated with HIV seropositivity; however, additional research is necessary to verify these mechanisms. Unique alcohol dosing formulas based on HIV serostatus may be required in future alcohol administration experiments involving HIV-positive samples.

The gut-liver axis and the intersection with the microbiome

In the past decade, an exciting realization has been that diverse liver diseases - ranging from nonalcoholic steatohepatitis, alcoholic steatohepatitis and cirrhosis to hepatocellular carcinoma - fall along a spectrum. Work on the biology of the gut-liver axis has assisted in understanding the basic biology of both alcoholic fatty liver disease and nonalcoholic fatty liver disease (NAFLD). Of immense importance is the advancement in understanding the role of the microbiome, driven by high-throughput DNA sequencing and improved computational techniques that enable the complexity of the microbiome to be interrogated, together with improved experimental designs. Here, we review gut-liver communications in liver disease, exploring the molecular, genetic and microbiome relationships and discussing prospects for exploiting the microbiome to determine liver disease stage and to predict the effects of pharmaceutical, dietary and other interventions at a population and individual level. Although much work remains to be done in understanding the relationship between the microbiome and liver disease, rapid progress towards clinical applications is being made, especially in study designs that complement human intervention studies with mechanistic work in mice that have been humanized in multiple respects, including the genetic, immunological and microbiome characteristics of individual patients. These 'avatar mice' could be especially useful for guiding new microbiome-based or microbiome-informed therapies.

Perceived driving safety and estimated blood alcohol concentration (BAC) the morning after drinking amongst young Australians attending a music festival: a cross-sectional survey

Background

Alcohol-related motor vehicle crashes remain a significant and costly public health issue globally. Particularly young people are over-represented in these incidents. This study set out to explore the factors that influence individuals’ perceptions of their safety to drive, and the factors related to a change in intention to drive.

Methods

Four hundred nine young people aged 18–40 attending an Australian multi-day music festival completed a survey measuring demographics, alcohol use, amount of sleep obtained the previous night, intention to drive, number of passengers, perceived safety to drive, estimated BAC (measured in g/210 L) and change in intention to drive following a BAC measurement via breathalysers. Statistical analyses involved univariate tests of association and multivariate logistic regression.

Results

Only one in five participants felt they were completely safe to drive. Males self-rated as less safe to drive than females. Multivariate analyses showed that licence class, sleep hours, units of alcohol consumed in the past 24 h and estimated BAC had statistically significant associations with driving safety perception. Participants who slept for greater than seven hours the previous night were three times more likely to feel safe to drive than those who had less than five hours of sleep (OR 3.05 (95% CI 1.25, 7.45)). Forty-one percent of participants changed their intended time of driving after having their BAC measured with a breathalyser. There was a statistically significant association between changing the intention to drive to a later time with an increase in each extra passenger in a participant’s vehicle (OR 1.53 (95% CI 1.02, 2.30)).

Conclusions

Whilst concerning behaviours relating to high-risk alcohol consumption were found, the study uncovered promising findings about young peoples’ perceptions of their safety to drive, and their propensity to change their driving intention. The strong correlation between hours of sleep, estimated BAC, units of alcohol consumed and license class with perception of driving safety suggests an increased awareness among young people and promotion of these factors may potentially improve actual driver safety. The influence of number of passengers on intention to drive later is another important consideration for future road safety research or promotion.