A Membrane Biophysics Perspective on the Mechanism of Alcohol Toxicity.

Motivations for understanding the underlying mechanisms of alcohol toxicity range from economical to toxicological and clinical. On the one hand, acute alcohol toxicity limits biofuel yields, and on the other hand, acute alcohol toxicity provides a vital defense mechanism to prevent the spread of disease. Herein the role that stored curvature elastic energy (SCE) in biological membranes might play in alcohol toxicity is discussed, for both short and long-chain alcohols. Structure-toxicity relationships for alcohols ranging from methanol to hexadecanol are collated, and estimates of alcohol toxicity per alcohol molecule in the cell membrane are made. The latter reveal a minimum toxicity value per molecule around butanol before alcohol toxicity per molecule increases to a maximum around decanol and subsequently decreases again. The impact of alcohol molecules on the lamellar to inverse hexagonal phase transition temperature (TH) is then presented and used as a metric to assess the impact of alcohol molecules on SCE. This approach suggests the nonmonotonic relationship between alcohol toxicity and chain length is consistent with SCE being a target of alcohol toxicity. Finally, in vivo evidence for SCE-driven adaptations to alcohol toxicity in the literature are discussed.

Effects of low-dose/high-dose-rate X-irradiation on oxidative stress in organs following forced swim test and its combined effects on alcohol-induced liver damage in mice.

The liver's susceptibility to oxidative stress after a combination of forced swim test (FST) and low-dose-rate γ-irradiation has been observed. Therefore, this study aims to clarify the effects of low-dose (0.1 and 0.5 Gy)/high-dose-rate (1.2 Gy/min) irradiation on combined oxidative stressors-liver damage associated with FST and alcohol administration. In addition, the effects of similar irradiation on FST-induced immobility, which induces psychomotor retardation, and antioxidative effects on the brain, lungs, liver and kidneys were investigated, and the results were compared with those of a similar previous study that utilized low-dose-rate irradiation. Low-dose/high-dose-rate (especially 0.5 Gy) irradiation temporarily worsened liver antioxidant function and hepatic function with FST- and alcohol administration-related oxidative damage; however, the damages improved soon after. In addition, the increase in total glutathione content in the liver contributed to the early improvement of hepatic functions. However, pre-irradiation did not suppress immobility during the FST. The results also suggested that the effects of low-dose/high-dose-rate irradiation on the antioxidant functions of each organ after the FST were different from those of low-dose/low-dose-rate irradiation. Overall, this study provides further insights into the effects of low-dose irradiation on exposure to a combination of different oxidative stressors. It will also contribute to the elucidation of dose rate effects on oxidative stress in the low-dose irradiation range.

In Vivo Attenuation of Alcohol- and Cadmium Chloride-Induced Testicular Toxicity Modulated by Silymarin in Male Wistar Rat.

The aim of the study is to investigate the in vivo attenuation of alcohol- and cadmium chloride-induced testicular toxicity modulated by Silymarin in male Wistar rats. A total of fifty-six (56) Wistar rats were used for this study and they were randomized into seven (7) groups of eight (8) rats each. Group 1 was control rats; Groups 2-7 served as the experimental groups. After 6 weeks treatment duration, the rats were euthanized, semen was collected for semen analysis, blood samples for testosterone, and FSH and LH assay determination, and left testes was harvested for histological analysis. One-way ANOVA was used to compare means at p-level < 0.05 was considered significant. Findings from this study have shown that alcohol and cadmium chloride adversely affected semen parameters, testosterone, and FSH and LH hormone milieu. Data also showed that Silymarin administration attenuated the adverse effect of alcohol and cadmium chloride on semen quality and hormones associated with reproductive functions. Hence, Silymarin mopped the effect of in vivo attenuation of alcohol and cadmium chloride testicular damage. The findings of this study have further established that alcohol and cadmium chloride adversely affected semen parameters, testicular alterations, and serum hormonal milieu. However, the effect was more significantly deleterious in rats exposed to cadmium chloride when compared to rats exposed to alcohol, subsequently alcohol- and cadmium chloride-induced degeneration of testicular tissues. Furthermore, Silymarin administration attenuated the adverse effect of alcohol on semen quality and hormones associated with reproductive functions.

Alcohol intoxication, but not hangover, differentially impairs learning and automatization of complex motor response sequences.

Behavioral automatization usually makes us more efficient and less error-prone, but may also foster dysfunctional behavior like alcohol abuse. Yet, it has remained unclear whether alcohol itself causes the shift from controlled to habitual behavior commonly observed in alcohol use disorder (AUD). We thus investigated how the acute and post-acute effects of binge drinking affect the automatization of motor response sequences and the execution of automated vs. controlled motor response sequences. N = 70 healthy young men performed a newly developed automatization paradigm once sober and once after binge drinking (half of them intoxicated and half of them hungover). While we found no significant effects of alcohol hangover, acute intoxication (~ 1.2 ‰) had two dissociable effects: Firstly, it impaired the automatization of complex motor response sequence execution. Secondly, it eliminated learning effects in response selection and pre-motor planning processes. The results suggest that alcohol hangover did not affect controlled or automated processes, and disprove the assumption that alcohol intoxication generally spares or facilitates motor response sequence automatization. As these effects could be specific to the investigated explicit learning context, acute intoxication might potentially still improve the execution of pre-existing automatisms and/or the implicit acquisition of motor response sequence automatisms.

Toxic Alcohols.

This article reviews the background, metabolism, clinical effects, and treatment of toxic alcohols, specifically ethylene glycol, methanol, diethylene glycol, propylene glycol, and isopropyl alcohol. This article also reviews the importance of an anion gap metabolic acidosis in relation to toxic alcohols and explores both the utility and the limitations of the osmole gap in patient management.

Aldehyde Dehydrogenase 2 Mediates Alcohol-Induced Colorectal Cancer Immune Escape through Stabilizing PD-L1 Expression.

Despite the great success of immunotherapy in a small subset of cancer patients, most colorectal cancer (CRC) patients do not respond to programmed cell death receptor 1 (PD-1) blockade immunotherapy. There is an urgent medical need to elucidate how cancer cells evade immune response and to develop novel means to boost the efficacy of immune checkpoint inhibitors. In this study, alcohol induces ligand programmed cell death receptor 1 (PD-L1) expression of CRC cells in vitro and in vivo. Alcohol exposure is shown to induce aldehyde dehydrogenase 2 (ALDH2) expression that is a crucial enzyme involved in alcohol metabolism, and low level of lymphocytes infiltration in the murine CRC model and patients. Intriguingly, ALDH2 and PD-L1 protein expression are positively correlated in tumor tissues from the CRC patients. Mechanistically, ALDH2 stabilizes PD-L1 protein expression by physically interacting with the intracellular segment of PD-L1 and inhibiting its proteasome-dependent degradation mediated by an E3 ubiquitin ligase Speckle Type POZ Protein (SPOP). Importantly, inhibition of ALDH2 reduces PD-L1 protein in CRC cells and promotes tumor-infiltrating T cells (TILs) infiltration, presumably leading to the significant potentiation of anti-PD-1 antibody efficacy in a mouse CT26 CRC model. The findings highlight a crucial role played by ALDH2 to facilitate alcohol-mediated tumor escape from immunity surveillance and promote tumor progression.

Establishment of a long-term hypertrophic scar model by injection of anhydrous alcohol: A rabbit model.

The processes of hypertrophic scar formation are extremely complex, and current animal models have limitations in terms of the complete characterization of lesions. An ideal animal model is indispensable for exploring the complex progression of scar formation to elucidate its pathophysiology and to perform therapeutic testing. This study aimed to establish a long-term, consistent and easily testable animal model by injecting anhydrous alcohol into the dorsal trunk dermis of rabbits. The rabbits were injected with different amounts of anhydrous alcohol. Anhydrous alcohol was infiltrated into the subcutaneous and superficial fascia. The optimal amount of anhydrous alcohol was determined by measuring the area and thickness of the scar. The typical model was established by determining the optimum dosage, and then we analysed the histological characteristics and fibrosis-associated protein expression. The dermal scar was generated by treating with 2 ml/kg anhydrous alcohol and displayed histopathologic features that characterize human hypertrophic scarring, including a parallel collagen fibre orientation, dermal and epidermal thickening, broad collagen deposition and the loss of dermal adnexal structures. The expression of fibrotic pan-markers was also enhanced. Moreover, the scar features and duration were compared between the anhydrous alcohol model and the rabbit ear model. Our results show that injecting anhydrous alcohol in the rabbit model thickened the dermal tissue, stimulated dermal fibroproliferation and resulted in hypertrophic scars with protein and histologic features similar to those seen in humans. Taken together, the findings from this study show that our model could be a feasible and useful tool for further research on the pathogenesis of hypertrophic scars.

LVV-hemorphin-7 (LVV-H7) plays a role in antinociception in a rat model of alcohol-induced pain disorders.

Alcohol can increase the sensitivity to painful stimulation or convert insensibility to pain at different stages. We hypothesized that chronic alcohol consumption changes the level of LVV-hemorphin-7 (abbreviated as LVV-H7, an opioid-like peptide generated from hemoglobin ß-chain), thereby affecting pain sensation. We established a chronic alcohol-exposed rat model to investigate the effects of LVV-H7. Adult male Sprague-Dawley rats were subjected to daily intraperitoneal injection of 10 % ethanol (w/v) at 0.5 g/kg for 15 days and subsequent alcohol withdrawal for 5 days. Using different pharmacological strategies to affect the LVV-H7 level, we investigated the correlation between LVV-H7 and pain-related behavior. Tail-flick and hot plate tests were employed to investigate alcohol-induced pain-related behavioral changes. The serum level of LVV-H7 was determined by ELISA. Our results showed that alcohol first induced an analgesia followed by a hyperalgesia during alcohol withdrawal, which could be driven by the quantitative change of LVV-H7. A positive correlation between the level of LVV-H7 and Δtail-flick latency (measured latency minus basal latency) confirmed this finding. Moreover, we revealed that the LVV-H7 levels were determined by the activity of cathepsin D and red blood cell/hemoglobin counts, which could be affected by alcohol. These results suggest that the deterioration of anti-nociception induced by alcohol is correlated to the decreased level of LVV-H7, and this could be due to alcohol-induced anemia. This study may help to develop LVV-H7 structure-based novel analgesics for treating alcohol-induced pain disorders and thus ameliorate the complications in alcoholics.

Chronic-plus-binge alcohol intake induces production of proinflammatory mtDNA-enriched extracellular vesicles and steatohepatitis via ASK1/p38MAPKα-dependent mechanisms.

Alcohol-associated liver disease is a spectrum of liver disorders with histopathological changes ranging from simple steatosis to steatohepatitis, cirrhosis, and hepatocellular carcinoma. Recent data suggest that chronic-plus-binge ethanol intake induces steatohepatitis by promoting release by hepatocytes of proinflammatory mitochondrial DNA-enriched (mtDNA-enriched) extracellular vesicles (EVs). The aim of the present study was to investigate the role of the stress kinase apoptosis signal-regulating kinase 1 (ASK1) and p38 mitogen-activated protein kinase (p38) in chronic-plus-binge ethanol-induced steatohepatitis and mtDNA-enriched EV release. Microarray analysis revealed the greatest hepatic upregulation of metallothionein 1 and 2 (Mt1/2), which encode 2 of the most potent antioxidant proteins. Genetic deletion of the Mt1 and Mt2 genes aggravated ethanol-induced liver injury, as evidenced by elevation of serum ALT, neutrophil infiltration, oxidative stress, and ASK1/p38 activation in the liver. Inhibition or genetic deletion of Ask1 or p38 ameliorated ethanol-induced liver injury, inflammation, ROS levels, and expression of phagocytic oxidase and ER stress markers in the liver. In addition, inhibition of ASK1 or p38 also attenuated ethanol-induced mtDNA-enriched EV secretion from hepatocytes. Taken together, these findings indicate that induction of hepatic mtDNA-enriched EVs by ethanol is dependent on ASK1 and p38, thereby promoting alcoholic steatohepatitis.

Pyrethroid-Derived Acids and Alcohols: Bioactivity and Synergistic Effects on Mosquito Repellency and Toxicity.

Pyrethroids are one of the most commonly used classes of insecticides, and their acid and alcohol components are esterase degradation products, usually considered to be biologically inactive. In this study, it was found that several pyrethroid acids had a spatial repellent activity that was greater than DEET, often more active than the parent pyrethroids, and showed little cross resistance in a pyrethroid-resistant Puerto Rico strain of Aedes aegypti mosquitoes. Further investigation revealed that the acids can synergize not only contact repellent standards but also other pyrethroid components as well as the parent pyrethroids themselves. Synergism by the pyrethroid acids is expressed as both increased spatial repellency and vapor toxicity as well as human bite protection. Electrophysiological studies confirmed that pyrethroid acids (100 µM) had no effect on neuronal discharge in larval Drosophila melanogaster CNS and were detected by electroantennography, and there was little resistance to olfactory sensing of these acids in antennae from Puerto Rico strain mosquitoes carrying kdr mutations. Thus, the data suggest that the pyrethroid acids have a different mode of action than the parent pyrethroids, unrelated to the voltage-sensitive sodium channel. The results highlight the potential of pyrethroid acids to be useful in future repellent formulations.

Comparative analysis of the toxicological databases for 6:2 fluorotelomer alcohol (6:2 FTOH) and perfluorohexanoic acid (PFHxA).

6:2 Fluorotelomer alcohol (6:2 FTOH) is a short-chain polyfluoroalkyl substance (PFAS) in polymeric PFAS used in fast food packaging and stain- and water-resistant textiles and may be degradation products of some components of aqueous film-forming foams (AFFF). The general population is exposed to 6:2 FTOH by inhalation of evaporates from treated surfaces or ambient concentrations in air, ingestion of indoor dust, or ingestion of food packaged in materials containing PFAS. Although exposure to 6:2 FTOH is pervasive, little is known concerning human health effects of this compound. Some published risk assessments have assumed that perfluorohexanoic acid (PFHxA), a metabolite of 6:2 FTOH, adequately models the human health effects of 6:2 FTOH. Recently identified studies conducted with 6:2 FTOH and its metabolite, 5:3 acid, have provided information that enables comparison of the toxicological profiles of PFHxA and 6:2 FTOH. This article summarizes a comparative analysis of the toxicological effects of PFHxA and 6:2 FTOH in rodents to determine whether data for PFHxA adequately models potential hazards of 6:2 FTOH exposure. Our analysis demonstrates that 6:2 FTOH is significantly more toxic than PFHxA. Use of toxicological studies conducted with PFHxA to assess 6:2 FTOH exposure may significantly underestimate human health risk.

Early dialysis in a rare case of combined toxic alcohols ingestion.

Ingestion of toxic alcohols (TA) typically presents with a high anion gap (AG) metabolic acidosis, and elevated osmolar gap (OG). Hemodialysis (HD) has not been recommended in early phases of intoxication with high OG and normal AG metabolic acidosis. We describe the case of a 40-year-old male who was brought to our emergency department for reported paint thinner ingestion. He was unable to protect his airway and required intubation. Blood gas showed respiratory acidosis, an initial AG, corrected by albumin of 12.75, lactic acid 5.26 mmol/L, and an OG of 170. Patient was treated with bicarbonate drip, fomepizole and emergent HD, which improved his neurologic status. Days after his admission, alcohol levels came positive for a co-ingestion of ethylene glycol, diethylene glycol, and methanol. Most of the TA are metabolized into their toxic byproducts by the enzyme alcohol dehydrogenase (ADH). The kinetics of these alcohols will be altered when there is co-ingestion of multiple substances. Moreover, early ingestions will translate in a high OG without a high AG. False elevation of lactate can occur with the ingestion of ethylene glycol due to a cross-reaction with L-lactate oxidase in the analyzer. In our case, the administration of fomepizole followed by an early HD given the poor clinical improvement, was followed by a fast recovery of the neurological status and potentially prevented renal failure. A high index of suspicion for TA ingestion should be raised when encountering an individual with lactic acidosis, high OG, and normal AG.

Persistence of Burkholderia thailandensis E264 in lung tissue after a single binge alcohol episode.

BACKGROUND: Binge drinking, an increasingly common form of alcohol use disorder, is associated with substantial morbidity and mortality; yet, its effects on the immune system's ability to defend against infectious agents are poorly understood. Burkholderia pseudomallei, the causative agent of melioidosis can occur in healthy humans, yet binge alcohol intoxication is increasingly being recognized as a major risk factor. Although our previous studies demonstrated that binge alcohol exposure increased B. pseudomallei near-neighbor virulence in vivo and increased paracellular diffusion and intracellular invasion, no experimental studies have examined the extent to which bacterial and alcohol dosage play a role in disease progression. In addition, the temporal effects of a single binge alcohol dose prior to infection has not been examined in vivo. PRINCIPAL FINDINGS: In this study, we used B. thailandensis E264 a close genetic relative of B. pseudomallei, as useful BSL-2 model system. Eight-week-old female C57BL/6 mice were utilized in three distinct animal models to address the effects of 1) bacterial dosage, 2) alcohol dosage, and 3) the temporal effects, of a single binge alcohol episode. Alcohol was administered comparable to human binge drinking (≤ 4.4 g/kg) or PBS intraperitoneally before a non-lethal intranasal infection. Bacterial colonization of lung and spleen was increased in mice administered alcohol even after bacterial dose was decreased 10-fold. Lung and not spleen tissue were colonized even after alcohol dosage was decreased 20 times below the U.S legal limit. Temporally, a single binge alcohol episode affected lung bacterial colonization for more than 24 h after alcohol was no longer detected in the blood. Pulmonary and splenic cytokine expression (TNF-α, GM-CSF) remained suppressed, while IL-12/p40 increased in mice administered alcohol 6 or 24 h prior to infection. Increased lung and not intestinal bacterial invasion was observed in human and murine non-phagocytic epithelial cells exposed to 0.2% v/v alcohol in vitro. CONCLUSIONS: Our results indicate that the effects of a single binge alcohol episode are tissue specific. A single binge alcohol intoxication event increases bacterial colonization in mouse lung tissue even after very low BACs and decreases the dose required to colonize the lungs with less virulent B. thailandensis. Additionally, the temporal effects of binge alcohol alters lung and spleen cytokine expression for at least 24 h after alcohol is detected in the blood. Delayed recovery in lung and not spleen tissue may provide a means for B. pseudomallei and near-neighbors to successfully colonize lung tissue through increased intracellular invasion of non-phagocytic cells in patients with hazardous alcohol intake.

Development, standardization, and validation of a biofilm efficacy test: The single tube method.

Methods validated by a standard setting organization enable public, industry and regulatory stakeholders to make decisions on the acceptability of products, devices and processes. This is because standard methods are demonstrably reproducible when performed in different laboratories by different researchers, responsive to different products, and rugged when small (usually inadvertent) variations from the standard procedure occur. The Single Tube Method (ASTM E2871) is a standard method that measures the efficacy of antimicrobials against biofilm bacteria that has been shown to be reproducible, responsive and rugged. In support of the reproducibility assessment, a six-laboratory study was performed using three antimicrobials: a sodium hypochlorite, a phenolic and a quaternary/alcohol blend, each tested at low and high efficacy levels. The mean log reduction in viable bacteria in this study ranged from 2.32 to 4.58 and the associated reproducibility standard deviations ranged from 0.89 to 1.67. Independent follow-up testing showed that the method was rugged with respect to deviations in sonication duration and sonication power but slightly sensitive to sonicator reservoir degassing and tube location within the sonicator bath. It was also demonstrated that when a coupon was dropped into a test tube, bacteria can splash out of reach of the applied antimicrobials, resulting in substantial bias when estimating log reductions for the products tested. Bias can also result when testing products that hinder the harvesting of microbes from test surfaces. The culmination of this work provided recommended changes to the early version of the standard method E2871-13 (ASTM, 2013b) including use of splashguards and microscopy checks. These changes have been incorporated into a revised ASTM method E2871-19 (ASTM 2019) that is the basis for the first regulatory method (ATMP-MB-20) to substantiate "kills biofilm" claims for antimicrobials registered and sold in the US.

Therapeutic and Protective Effects of Liposomal Encapsulation of Astaxanthin in Mice with Alcoholic Liver Fibrosis.

Astaxanthin (Asta) has been demonstrated to possess anti-inflammatory, antitumor, and free radical-clearing activities. However, the poor stability and low water solubility of Asta hamper its bioavailability. The objectives of this study were to fabricate Asta-loaded liposomes (Asta-lipo) and investigate the therapeutic effects of Asta-lipo on alcoholic liver fibrosis in mice. The mice were administered with Asta-lipo or liposomes alone prior to a 3-week dose containing 30% alcohol with or without feeding with a second dose of 30% alcohol. The prepared Asta-lipo of 225.0 ± 58.3 nm in diameter, had an encapsulation efficiency of 98%. A slow release profile of 16.2% Asta from Asta-lipo was observed after a 24-h incubation. Restorative actions against alcoholic liver fibrosis were observed after oral administration of Asta-lipo for 4 weeks. Hepatic repair, followed by a second dose of 30% alcohol, suggested that Asta-lipo exerted protective and reparative effects against liver injuries induced by repeated consumption of alcohol. The changes of serum ALT and AST values were principally in consistence with the histopathologic findings. Asta-lipo exerted rapid and direct effects against repeated alcohol-induced liver disease, whereas Asta-lipo given orally could boost recovery from liver injuries obtained due to previous long-term alcohol use. These data demonstrate that Asta-lipo has applicable protective and therapeutic potential to treat alcohol-induced liver diseases.

Predicting development of adolescent drinking behaviour from whole brain structure at 14 years of age.

Adolescence is a common time for initiation of alcohol use and development of alcohol use disorders. The present study investigates neuroanatomical predictors for trajectories of future alcohol use based on a novel voxel-wise whole-brain structural equation modeling framework. In 1814 healthy adolescents of the IMAGEN sample, the Alcohol Use Disorder Identification Test (AUDIT) was acquired at three measurement occasions across five years. Based on a two-part latent growth curve model, we conducted whole-brain analyses on structural MRI data at age 14, predicting change in alcohol use score over time. Higher grey-matter volumes in the caudate nucleus and the left cerebellum at age 14 years were predictive of stronger increase in alcohol use score over 5 years. The study is the first to demonstrate the feasibility of running separate voxel-wise structural equation models thereby opening new avenues for data analysis in brain imaging.