Inhibitor Of Alcohol Dehydrogenase Research Articles

Symptomatic Diethylene Glycol Ingestion Successfully Treated with Fomepizole Monotherapy

BackgroundDiethylene glycol (DEG) is an industrial solvent with many uses, including brake fluids. It has also caused mass poisonings after use as an inappropriate substitute for propylene glycol or glycerin, though individual ingestions are rare. Like other toxic alcohols, DEG is metabolized by alcohol dehydrogenase and aldehyde dehydrogenase, with toxicity likely mediated by the resulting metabolites. Fomepizole, an alcohol dehydrogenase inhibitor, is used to prevent metabolite formation with other toxic alcohol exposures. Fomepizole is recommended for DEG poisoning, though supporting clinical evidence is limited. Case ReportA 31-year-old man presented after ingestion of DEG-containing brake fluid and hydrocarbon-containing “octane booster.” He was noted to be clinically intoxicated, with a mildly elevated anion gap metabolic acidosis and no osmolar gap. DEG level was later found to be elevated, consistent with his ingestion. He was treated with fomepizole alone, with resolution of metabolic acidosis and clinical findings over the next 2 days. No delayed neurologic sequelae were present at 52-day follow-up. Our case provides additional evidence supporting the use of fomepizole for DEG poisoning. Consistent with other toxic alcohols, DEG poisoning, especially early presentations, may benefit from empiric fomepizole administration. Why Should an Emergency Physician Be Aware of This?DEG poisoning is potentially life threatening, but treatable if identified early. An ingestion can be toxic despite a normal osmolar gap, leading to false reassurance. Finally, it is rare, so emergency physicians must be made aware of its potential dangers.

In silico Investigations on Structure, Reactivity Indices, NLO properties, and Bio-evaluation of 1-benzyl-2-phenyl-1H-benzimidazole Derivatives using DFT and Molecular Docking Approaches

Six 1-benzyl-2-phenyl-1H-benzimidazole derivatives, A1-A6, were modeled computationally, and equilibrium optimization was carried out at the B3LYP/6-31G** level of theory. The geometrical parameters, IR, UV-Vis, and molecular reactive properties were predicted on the basis of density functional theory (DFT) calculations. The electron-donating/accepting power (𝜔−/𝜔+) calculated were 4.71/1.18, 5.675/1.766, and 4.785/1.210 eV for A1, A2, and A3, respectively, indicating good electron donors; while A4 and A5 were calculated to be 8.13/3.60 and 9.284/4.744 eV, respectively signifying good electron acceptors in line with chemical hardness (μ), electrophilicity (ω) values and MEP analysis. The NLO behavior of compounds A1-A3 was greater than that of the standard NLO material urea gives the most reactive sites in the molecules. Docking analysis revealed that binding affinities for the six compounds A1-A6 were -8.3 to -9.0 kcal/mol and -9.2 to -10.0 kcal/mol for APO-liver alcohol dehydrogenase inhibitor (PDB IP: 5ADH) and antihypertensive protein hydrolase inhibitor (PDB IP: 4XX3), respectively; thus could possess good antioxidant and antihypertensive properties.

TRPV6 channel mediates alcohol-induced gut barrier dysfunction and systemic response.

SUMMARYIntestinal epithelial tight junction disruption is a primary contributing factor in alcohol-associated endotoxemia, systemic inflammation, and multiple organ damage. Ethanol and acetaldehyde disrupt tight junctions by elevating intracellular Ca2+. Here we identify TRPV6, a Ca2+-permeable channel, as responsible for alcohol-induced elevation of intracellular Ca2+, intestinal barrier dysfunction, and systemic inflammation. Ethanol and acetaldehyde elicit TRPV6 ionic currents in Caco-2 cells. Studies in Caco-2 cell monolayers and mouse intestinal organoids show that TRPV6 deficiency or inhibition attenuates ethanol- and acetaldehyde-induced Ca2+ influx, tight junction disruption, and barrier dysfunction. Moreover, Trpv6−/− mice are resistant to alcohol-induced intestinal barrier dysfunction. Photoaffinity labeling of 3-azibutanol identifies a histidine as a potential alcohol-binding site in TRPV6. The substitution of this histidine, and a nearby arginine, reduces ethanol-activated currents. Our findings reveal that TRPV6 is required for alcohol-induced gut barrier dysfunction and inflammation. Molecules that decrease TRPV6 function have the potential to attenuate alcohol-associated tissue injury.

Ingestion of Alcohol-Based Hand Sanitizer: A case report

IntroductionAlcohol-based hand sanitizers containing ethanol or isopropanol are being used in order to prevent person-to-person transmission during the COVID-19. Early signs and symptoms of this ingestion include nausea, vomiting, headache, abdominal pain, blurred vision, loss of coordination, and decreased level of consciousness. After hand sanitizer ingestion we have to suspect about methanol poisoning, monitoring the start of anion-gap metabolic acidosis, seizures, and blindness is essential. Treatment includes supportive care, acidosis correction, and the administration of an alcohol dehydrogenase inhibitor. In servere cases hemodialysis may be required.Objectives To present a case of an 29-year-old woman who was taken to the emergency department after voluntary ingestion of alcohol-based hand sanitizer in a suicide attempt. To describe the most common side effects of hand sanitizer ingestion and the literature review.MethodsClinical case presentation and literature review of similar cases.ResultsA 29-year-old woman, with diagnosis of borderline personality disorder and previous suicide attempts was taken to the emergency department after 3 hours of voluntary ingestion of an unknown quantity of alcohol-based hand sanitizer. Initial laboratory findings showed laboratory a blood methanol concentration of 66 mg/dL, with an anion gap of 30 mEq/L, arterial blood pH of 7.2, serum bicarbonate concentration of 12 mEq/L. Patient complained of abdominal pain and nervoussness.ConclusionsMost common signs and symptoms of alcohol-based hand sanitizer ingestion include nausea, vomiting, headache, abdominal pain, blurred vision, loss of coordination, and decreased level of consciousness. Treatment includes supportive care, acidosis correction, the administration of an alcohol dehydrogenase inhibitor and sometimes may be required.DisclosureNo significant relationships.

10-Hydroxy-2-decenoic acid-derived aldehydes attenuate anaphylactic hypothermia in vivo

BackgroundA royal jelly-derived unique fatty acid, 10-hydroxy-2-decenoic acid (10-HDA), attenuates anaphylactic hypothermia by inhibiting the bioactivities of platelet-activating factor (PAF) and histamine, which are known mediators of anaphylaxis in vivo. Here, we investigated the effects of 10-HDA and its two metabolites, 2-decenedioic acid (2-DA) and 3-hydroxysebacic acid (3-HSA), on anaphylactic hypothermia targeting PAF and histamine in vivo. MethodsThe effects of 10-HDA and its metabolites on the bioactivities of PAF and histamine, and anaphylactic hypothermia were evaluated in a rat hind paw edema model and an anaphylactic mouse model. ResultsThe metabolites, 2-DA and 3-HSA, barely inhibited histamine- and PAF-induced paw edema in rats. Oral ingestion of 10-HDA (0.002 % and 0.02 %) with food attenuated anaphylactic hypothermia in a dose-dependent manner, whereas intraperitoneal injection of 2-DA or 3-HSA did not inhibit hypothermia. 4-Methylpyrazole, an inhibitor of alcohol dehydrogenase, which converts 10-HDA to its aldehydes, 10-oxo-decenoic acid (10-ODA) and 10-oxo-3-hydroxysebacic acid (10-OHSA), inhibited 10-HDA-induced attenuation of anaphylactic hypothermia. In contrast, cyanamide, an inhibitor of aldehyde dehydrogenase, which converts 10-ODA and 10-OHSA to 2-DA and 3-HSA enhanced the attenuation effect of 10-HDA. ConclusionsThe results suggest that 10-HDA-derived aldehydes, 10-ODA and 10-OHSA, may play a key role in the attenuation of anaphylactic hypothermia in vivo.

A two-directional vibrational probe reveals different electric field orientations in solution and an enzyme active site.

The catalytic power of an electric field depends on its magnitude and orientation with respect to the reactive chemical species. Understanding and designing new catalysts for electrostatic catalysis thus requires methods to measure the electric field orientation and magnitude at the molecular scale. We demonstrate that electric field orientations can be extracted using a two-directional vibrational probe by exploiting the vibrational Stark effect of both the C=O and C-D stretches of a deuterated aldehyde. Combining spectroscopy with molecular dynamics and electronic structure partitioning methods, we demonstrate that, despite distinct polarities, solvents act similarly in their preference for electrostatically stabilizing large bond dipoles at the expense of destabilizing small ones. In contrast, we find that for an active-site aldehyde inhibitor of liver alcohol dehydrogenase, the electric field orientation deviates markedly from that found in solvents, which provides direct evidence for the fundamental difference between the electrostatic environment of solvents and that of a preorganized enzyme active site.

Treating ethylene glycol poisoning with alcohol dehydrogenase inhibition, but without extracorporeal treatments: a systematic review

Context Ethylene glycol is metabolized to toxic metabolites that cause acute kidney injury, metabolic acidemia, and death. The treatment of patients with ethylene glycol poisoning includes competitively inhibiting alcohol dehydrogenase with ethanol or fomepizole to prevent the formation of toxic metabolites, and extracorporeal treatments such as hemodialysis to remove ethylene glycol and its metabolites. In the absence of significant metabolic acidemia or kidney injury, it is hypothesized that extracorporeal treatments may be obviated without adverse outcomes to the patient if alcohol dehydrogenase inhibitors are used. Objectives The objectives of this study are to: (1) identify indicators predicting ADH inhibitor failure in patients with ethylene glycol poisoning treated with either ethanol or fomepizole for whom extracorporeal treatment was not performed (aside from rescue therapy, see below) (prognostic study), and (2) validate if the anion gap, shown in a previous study to be the best surrogate for the glycolate concentration, is associated with acute kidney injury and mortality (anion gap study). Methods We conducted a systematic review to identify all reported patients with ethylene glycol poisoning treated without extracorporeal treatments but with either fomepizole (fomepizole monotherapy) or ethanol (ethanol monotherapy). Analyses were performed using both one case per patient and all cases (if multiple events were reported for a single patient). Data were compiled regarding poisoning, biochemistry, and outcomes. Treatment failure was defined as mortality, worsening of acid-base status, extracorporeal treatments used as rescue, or a worsening of kidney or neurological function after alcohol dehydrogenase inhibition was initiated. Also, we performed an analysis of previously described anion gap thresholds to determine if they were associated with outcomes such as acute kidney injury and mortality. Results Of 115 publications identified, 96 contained case-level data. A total of 180 cases were identified with ethanol monotherapy, and 231 with fomepizole monotherapy. Therapy failure was noted mostly when marked acidemia and/or acute kidney injury were present prior to therapy, although there were cases of failed ethanol monotherapy with minimal acidemia (suggesting that ethanol dosing and/or monitoring may not have been optimal). Ethylene glycol dose and ethylene glycol concentration were predictive of monotherapy failure for ethanol, but not for fomepizole. In the anion gap study (207 cases), death and progression of acute kidney injury were almost nonexistent when the anion gap was less than 24 mmol/L and mostly observed when the anion gap was greater than 28 mmol/L. Conclusion This review suggests that in patients with minimal metabolic acidemia (anion gap <28 mmol/L), fomepizole monotherapy without extracorporeal treatments is safe and effective regardless of the ethylene glycol concentration. Treatment failures were observed with ethanol monotherapy which may relate to transient subtherapeutic ethanol concentrations or very high ethylene glycol concentrations. The results are limited by the retrospective nature of the case reports and series reviewed in this study and require prospective validation.

Unintentional ethylene glycol ingestions in children

ABSTRACT Background: Toxic alcohol poisoning may result in severe acidemia and death. Previous work from our regional poison center (RPC) revealed that most pediatric unintentional methanol exposures are benign and do not require alcohol dehydrogenase (ADH) blockade or hemodialysis. Methods: We retrospectively reviewed all ethylene glycol (EG) cases in patients less than 6 years of age reported to our RPC over a 19 year period. We included unintentional ingestions with measured EG concentrations. Results: Twenty-nine cases met inclusion criteria. EG concentrations were undetectable in 25 cases (86%). No patient became symptomatic or acidemic. No EG concentration warranted treatment with ADH inhibition or hemodialysis. However, 21 patients (72%) received fomepizole or ethanol. Fifteen patients (52%) transferred from a community hospital to a pediatric specialty hospital. All 27 children admitted to the hospital went to a pediatric intensive care unit (PICU) while awaiting EG results. Conclusions: No child during the 19-year period required either antidote or hemodialysis. Unintentional EG exposures in typical pediatric patients may warrant nothing more than repeat laboratory testing (electrolytes, pH) to exclude evolving toxicity. Timely availability of EG laboratory test results would likely reduce unnecessary and expensive use of antidote, transport, and PICU resources.

Functional Characteristics of Aldehyde Dehydrogenase and Its Involvement in Aromatic Volatile Biosynthesis in Postharvest Banana Ripening.

Butanol vapor feeding to ripe banana pulp slices produced abundant butyl butanoate, indicating that a portion of butanol molecules was converted to butanoate/butanoyl-CoA via butanal, and further biosynthesized to ester. A similar phenomenon was observed when feeding propanol and pentanol, but was less pronounced when feeding hexanol, 2-methylpropanol and 3-methylbutanol. Enzymes which catalyze the cascade reactions, such as alcohol dehydrogenase (ADH), acetyl-CoA synthetase, and alcohol acetyl transferase, have been well documented. Aldehyde dehydrogenase (ALDH), which is presumed to play a key role in the pathway to convert aldehydes to carboxylic acids, has not been reported yet. The conversion is an oxygen-independent metabolic pathway and is enzyme-catalyzed with nicotinamide adenine dinucleotide (NAD+) as the cofactor. Crude ALDH was extracted from ripe banana pulps, and the interference from ADH was removed by two procedures: (1) washing off elutable proteins which contain 95% of ADH, but only about 40% of ALDH activity, with the remaining ALDH extracted from the pellet residues at the crude ALDH extraction stage; (2) adding an ADH inhibitor in the reaction mixture. The optimum pH of the ALDH was 8.8, and optimum phosphate buffer concentration was higher than 100 mM. High affinity of the enzyme was a straight chain of lower aldehydes except ethanal, while poor affinity was branched chain aldehydes.

Silymarin Dehydroflavonolignans Chelate Zinc and Partially Inhibit Alcohol Dehydrogenase

Silymarin is known for its hepatoprotective effects. Although there is solid evidence for its protective effects against Amanita phalloides intoxication, only inconclusive data are available for alcoholic liver damage. Since silymarin flavonolignans have metal-chelating activity, we hypothesized that silymarin may influence alcoholic liver damage by inhibiting zinc-containing alcohol dehydrogenase (ADH). Therefore, we tested the zinc-chelating activity of pure silymarin flavonolignans and their effect on yeast and equine ADH. The most active compounds were also tested on bovine glutamate dehydrogenase, an enzyme blocked by zinc ions. Of the six flavonolignans tested, only 2,3-dehydroderivatives (2,3-dehydrosilybin and 2,3-dehydrosilychristin) significantly chelated zinc ions. Their effect on yeast ADH was modest but stronger than that of the clinically used ADH inhibitor fomepizole. In contrast, fomepizole strongly blocked mammalian (equine) ADH. 2,3-Dehydrosilybin at low micromolar concentrations also partially inhibited this enzyme. These results were confirmed by in silico docking of active dehydroflavonolignans with equine ADH. Glutamate dehydrogenase activity was decreased by zinc ions in a concentration-dependent manner, and this inhibition was abolished by a standard zinc chelating agent. In contrast, 2,3-dehydroflavonolignans blocked the enzyme both in the absence and presence of zinc ions. Therefore, 2,3-dehydrosilybin might have a biologically relevant inhibitory effect on ADH and glutamate dehydrogenase.

COMBINATION THERAPY WITH N-ACETYLCYSTEINE AND 4-METHYLPYRAZOLE FOR ACETAMINOPHEN OVERDOSE

TOPIC: Critical Care TYPE: Medical Student/Resident Case Reports INTRODUCTION: Acetaminophen (APAP) overdose is the most common cause of acute liver failure in the United States. We report a case of a patient who presented with acetaminophen overdose and was successfully treated with N-acetylcysteine (NAC) and 4-methylpyrazole (4-MP). CASE PRESENTATION: A 58-year-old female with history of alcohol abuse, hypertension, and hyperlipidemia presented with abdominal pain, nausea, and vomiting. Patient had fallen several days prior, resulting in rib fractures, and had been taking APAP for pain relief. Vital signs were within normal limits. Physical exam showed a lethargic, encephalopathic patient who only followed simple commands and had right upper quadrant abdominal tenderness. Labs revealed total bilirubin 6.4, AST 19816, ALT 5544, INR 3.7, acetaminophen level 58.3, lactic acid 12.2, creatinine 3.1, lipase 1187, and ammonia 82. Imaging was consistent with hepatic steatosis. Patient was treated with aggressive fluid resuscitation for pancreatitis; NAC and 4-MP for acetaminophen toxicity; lactulose and rifaximin for hepatic encephalopathy; vitamin K for coagulopathy; and albumin, octreotide, and midodrine for hepatorenal syndrome. Mental status and lab abnormalities gradually improved and acetaminophen level became undetectable. DISCUSSION: Our patient presented with unintentional APAP overdose. She likely had underlying chronic liver disease, as evidenced by hepatic steatosis on imaging, due to alcohol abuse. This likely made her more susceptible to liver injury, even with therapeutic doses of APAP.The pathogenesis APAP-induced hepatotoxicity starts with the conversion of APAP to N-acetyl-p-benzoquinone imine (NAPQI) by cytochrome P450 enzymes, which is detoxified by conjunction with glutathione.[1] When excessive amounts of APAP are ingested, hepatic glutathione levels are depleted, resulting in oxidant stress. NAC, the current standard of care and only clinically approved treatment for APAP overdose, attempts to limit this by accelerating glutathione synthesis and subsequent scavenging of NAPQI.[2]Recent literature has suggested that 4-MP may also be beneficial for attenuating liver injury in APAP overdose. 4-MP is classically known for its inhibition of alcohol dehydrogenase in methanol or ethylene glycol poisoning. However, it is unique in that it also directly inhibits CYP2E1, one of the major enzymes involved in the generation of NAPQI. 4-MP has been shown to be effective at preventing APAP-induced liver injury in mice and human hepatocytes and limiting oxidative metabolism in five human volunteers who ingested supratherapeutic APAP doses.[1,2] It may also protect against APAP-induced nephrotoxicity via a similar mechanism.[3] CONCLUSIONS: In patients presenting with APAP overdose, combination therapy with NAC and 4-MP may provide complementary protective effects through targeting of different therapeutic pathways. REFERENCE #1: Kang AM, Padilla-Jones A, Fisher ES, et al. The effect of 4-methylpyrazole on oxidative metabolism of acetaminophen in human volunteers. J Med Toxicol. 2020;16(2):169-176. REFERENCE #2: Akakpo JY, Ramachandran A, Kandel SE, et al. 4-Methylpyrazole protects against acetaminophen hepatotoxicity in mice and in primary human hepatocytes. Hum Exp Toxicol. 2018;37(12):1310-1322. REFERENCE #3: Akakpo JY, Ramachandran A, Orhan H, et al. 4-methylpyrazole protects against acetaminophen-induced acute kidney injury. Toxicol Appl Pharmacol. 2020;409:115317. DISCLOSURES: No relevant relationships by Travis Homan, source=Web Response No relevant relationships by Brittany Wichman, source=Web Response

Ethylene Glycol Intoxication Requiring ECMO Support

Ethylene glycol is commonly used in antifreeze, and ingestion of even a small amount can result in acute kidney injury, severe metabolic acidosis, and neurological injury. When cases are recognized early, treatment involves administration of alcohol dehydrogenase inhibitors to prevent conversion to toxic metabolites of glycolate, glyoxolate, and oxalate. In later presentations with more severe renal injury, hemodialysis may be required for clearance of toxic metabolites and supportive care for renal failure. We present the first reported case of severe ethylene glycol intoxication requiring support of extracorporeal membrane oxygenation (ECMO) due to refractory cardiopulmonary collapse.

Physiological Responses of Young Pea and Barley Seedlings to Plasma-Activated Water.

This study demonstrates the indirect effects of non-thermal ambient air plasmas (NTP) on seed germination and plant growth. It investigates the effect of plasma-activated water (PAW) on 3-day-old seedlings of two important farm plants—barley and pea. Applying different types of PAW on pea seedlings exhibited stimulation of amylase activity and had no inhibition of seed germination, total protein concentration or protease activity. Moreover, PAW caused no or only moderate oxidative stress that was in most cases effectively alleviated by antioxidant enzymes and proved by in situ visualization of H2O2 and ˙O2−. In pea seedlings, we observed a faster turn-over from anaerobic to aerobic metabolism proved by inhibition of alcohol dehydrogenase (ADH) activity. Additionally, reactive oxygen/nitrogen species contained in PAW did not affect the DNA integrity. On the other hand, the high level of DNA damage in barley together with the reduced root and shoot length and amylase activity was attributed to the oxidative stress caused by PAW, which was exhibited by the enhanced activity of guaiacol peroxidase or ADH. Our results show the glow discharge PAW at 1 min activation time as the most promising for pea. However, determining the beneficial type of PAW for barley requires further investigation.

The methylimidazolium ionic liquid M8OI is detectable in human sera and is subject to biliary excretion in perfused human liver

A methylimidizolium ionic liquid (M8OI) was recently found to be contaminating the environment and to be related to and/or potentially a component of an environmental trigger for the autoimmune liver disease primary biliary cholangitis (PBC). The aims of this study were to investigate human exposure to M8OI, hepatic metabolism and excretion. PBC patient and control sera were screened for the presence of M8OI. Human livers were perfused with 50μM M8OI in a closed circuit and its hepatic disposition examined. Metabolism was examined in cultured human hepatocytes and differentiated HepaRG cells by the addition of M8OI and metabolites in the range 10–100 μM. M8OI was detected in the sera from 5/20 PBC patients and 1/10 controls. In perfused livers, M8OI was cleared from the plasma with its appearance – primarily in the form of its hydroxylated (HO8IM) and carboxylated (COOH7IM) products – in the bile. Metabolism was reflected in cultured hepatocytes with HO8IM production inhibited by the cytochrome P450 inhibitor ketoconazole. Further oxidation of HO8IM to COOH7IM was sequentially inhibited by the alcohol and acetaldehyde dehydrogenase inhibitors 4-methyl pyrazole and disulfiram respectively. Hepatocytes from 1 donor failed to metabolise M8OI to COOH7IM over a 24 h period. These results demonstrate exposure to M8OI in the human population, monooxygenation by cytochromes P450 followed by alcohol and acetaldehyde dehydrogenase oxidation to a carboxylic acid that are excreted, in part, via the bile in human liver.

The fructose-dependent acceleration of ethanol metabolism

The aim of the present study was to elucidate how fructose is able to increase the rate of ethanol metabolism in the liver, an observation previously termed the fructose effect. Previous studies suggest that an increase in ATP consumption driven by glucose synthesis from fructose stimulates the oxidation of NADH in the mitochondrial respiratory chain, allowing faster oxidation of ethanol by alcohol dehydrogenase; however, this idea has been frequently challenged. We tested the effects of fructose, sorbose and tagatose both in vitro and in vivo. Both ethanol and each sugar were either added to isolated hepatocytes or injected intraperitoneally in the rat. In the in vitro experiments, samples were taken from the hepatocyte suspension in a time-dependent manner and deproteinized with perchloric acid. In the in vivo experiments, blood samples were taken every 15 min and the metabolites were determined in the plasma. These metabolites include ethanol, glucose, glycerol, sorbitol, lactate, fructose and sorbose. Ethanol oxidation by rat hepatocytes was increased by more than 50% with the addition of fructose. The stimulation was accompanied by increased glucose, glycerol, lactate and sorbitol production. A similar effect was observed with sorbose, while tagatose had no effect. The same pattern was observed in the in vivo experiments. This effect was abolished by inhibiting alcohol dehydrogenase with 4-methylpyrazole, whereas inhibition of the respiratory chain with cyanide did not affect the fructose effect. In conclusion, present results provide evidence that, by reducing glyceraldehyde and glycerol and fructose to sorbitol, respectively, NADH is consumed, allowing an increase in the elimination of ethanol. Hence, this effect is not linked to a stimulation of mitochondrial re-oxidation of NADH driven by ATP consumption.

Ethanol Disrupts Hormone-Induced Calcium Signaling in Liver.

Receptor-coupled phospholipase C (PLC) is an important target for the actions of ethanol. In the ex vivo perfused rat liver, concentrations of ethanol >100 mM were required to induce a rise in cytosolic calcium (Ca2+) suggesting that these responses may only occur after binge ethanol consumption. Conversely, pharmacologically achievable concentrations of ethanol (≤30 mM) decreased the frequency and magnitude of hormone-stimulated cytosolic and nuclear Ca2+ oscillations and the parallel translocation of protein kinase C-β to the membrane. Ethanol also inhibited gap junction communication resulting in the loss of coordinated and spatially organized intercellular Ca2+ waves in hepatic lobules. Increasing the hormone concentration overcame the effects of ethanol on the frequency of Ca2+ oscillations and amplitude of the individual Ca2+ transients; however, the Ca2+ responses in the intact liver remained disorganized at the intercellular level, suggesting that gap junctions were still inhibited. Pretreating hepatocytes with an alcohol dehydrogenase inhibitor suppressed the effects of ethanol on hormone-induced Ca2+ increases, whereas inhibiting aldehyde dehydrogenase potentiated the inhibitory actions of ethanol, suggesting that acetaldehyde is the underlying mediator. Acute ethanol intoxication inhibited the rate of rise and the magnitude of hormone-stimulated production of inositol 1,4,5-trisphosphate (IP3), but had no effect on the size of Ca2+ spikes induced by photolysis of caged IP3. These findings suggest that ethanol inhibits PLC activity, but does not affect IP3 receptor function. We propose that by suppressing hormone-stimulated PLC activity, ethanol interferes with the dynamic modulation of [IP3] that is required to generate large, amplitude Ca2+ oscillations.

Folic acid in methanol toxicity: a retrospective cohort study

Folic acid is a proposed adjunct to alcohol dehydrogenase inhibitors and hemodialysis (HD) in the treatment of methanol toxicity. Although animal models have shown increased formate clearance, human data regarding its efficacy are lacking. We performed a 7-year retrospective chart review of patients with methanol concentrations >10 mg/dL. We compared patients receiving scheduled dosing of 50 mg of folic acid (folate group) to those receiving no folic/folinic acid or <50 mg folic or folinic acid (low/no folate). We excluded patients who did not require hospitalization, those with alternative causes of acidosis, and those who died prior to therapy. The primary outcome measures were worsening metabolic acidosis, length of stay (LOS), and half-life of methanol. Of 27 patient visits with methanol concentration >10 mg/dL, 14 visits (11 patients) met inclusion criteria. Initial pH and methanol concentrations were similar between the two groups. There was no difference in LOS. No patients had worsening metabolic acidosis during therapy. In patients treated with and without HD, median half-lives of methanol were similar in both groups. Folic acid treatment provided no additional benefit to standard therapy for methanol toxicity. We cannot exclude potential benefit of folic acid on formate clearance.

Serious Adverse Health Events, Including Death, Associated with Ingesting Alcohol-Based Hand Sanitizers Containing Methanol - Arizona and New Mexico, May-June 2020.

Alcohol-based hand sanitizer is a liquid, gel, or foam that contains ethanol or isopropanol used to disinfect hands. Hand hygiene is an important component of the U.S. response to the emergence of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19). If soap and water are not readily available, CDC recommends the use of alcohol-based hand sanitizer products that contain at least 60% ethyl alcohol (ethanol) or 70% isopropyl alcohol (isopropanol) in community settings (1); in health care settings, CDC recommendations specify that alcohol-based hand sanitizer products should contain 60%-95% alcohol (≥60% ethanol or ≥70% isopropanol) (2). According to the Food and Drug Administration (FDA), which regulates alcohol-based hand sanitizers as an over-the-counter drug, methanol (methyl alcohol) is not an acceptable ingredient. Cases of ethanol toxicity following ingestion of alcohol-based hand sanitizer products have been reported in persons with alcohol use disorder (3,4). On June 30, 2020, CDC received notification from public health partners in Arizona and New Mexico of cases of methanol poisoning associated with ingestion of alcohol-based hand sanitizers. The case reports followed an FDA consumer alert issued on June 19, 2020, warning about specific hand sanitizers that contain methanol. Whereas early clinical effects of methanol and ethanol poisoning are similar (e.g., headache, blurred vision, nausea, vomiting, abdominal pain, loss of coordination, and decreased level of consciousness), persons with methanol poisoning might develop severe anion-gap metabolic acidosis, seizures, and blindness. If left untreated methanol poisoning can be fatal (5). Survivors of methanol poisoning might have permanent visual impairment, including complete vision loss; data suggest that vision loss results from the direct toxic effect of formate, a toxic anion metabolite of methanol, on the optic nerve (6). CDC and state partners established a case definition of alcohol-based hand sanitizer-associated methanol poisoning and reviewed 62 poison center call records from May 1 through June 30, 2020, to characterize reported cases. Medical records were reviewed to abstract details missing from poison center call records. During this period, 15 adult patients met the case definition, including persons who were American Indian/Alaska Native (AI/AN). All had ingested an alcohol-based hand sanitizer and were subsequently admitted to a hospital. Four patients died and three were discharged with vision impairment. Persons should never ingest alcohol-based hand sanitizer, avoid use of specific imported products found to contain methanol, and continue to monitor FDA guidance (7). Clinicians should maintain a high index of suspicion for methanol poisoning when evaluating adult or pediatric patients with reported swallowing of an alcohol-based hand sanitizer product or with symptoms, signs, and laboratory findings (e.g., elevated anion-gap metabolic acidosis) compatible with methanol poisoning. Treatment of methanol poisoning includes supportive care, correction of acidosis, administration of an alcohol dehydrogenase inhibitor (e.g., fomepizole), and frequently, hemodialysis.

Alcohol dehydrogenase modulates quorum sensing in biofilm formations of Acinetobacter baumannii

Acinetobacter baumannii (A. baumannii) is a common opportunistic nosocomial pathogen, which is able to produce biofilms on the surface of indwelling medical devices, and consequentially causes severe infections in clinical settings. In order to identify genes that involved in the biofilm formation of A. baumannii, the differential expression of genes between biofilms and planktonic cells was analyzed by RNAseq assay and validated in clinical isolates. The RNAseq data showed that 264 genes were up-regulated, while 240 genes were down-regulated in the biofilms of A. baumannii. Among them, the gene encoding alcohol dehydrogenase (ADH), a known molecule of bacterial quorum sensing (QS) system that plays a key role in biofilm formation bacteria, was one of the most up-regulated gene in both reference strains and clinical isolates. Functional studies using ADH inhibitor disulfiram and activator taurine further demonstrated that the presence of disulfiram significantly inhibit the cell growth, motility and biofilm formation, paralleled by a decreased expression of QS-related genes, including AbaI, A1S_0109, and A1S_0112, in a dose-dependent manner; vice versa, the addition of ADH activator taurine, and QS molecule C12- homoserine lactone synthase (HSL) led a dose-dependent increase of bacterial growth, motility and biofilm production, along with an increased expression of QS-related genes in both reference strains and clinical isolates of A. baumannii. These results suggested that the ADH was a key molecule able to modulate the QS system and promote the biofilm formation, growth and motility in A. baumannii.

Higher sensitivity of female cells to ethanol: methylation of DNA lowers Cyp2e1, generating more ROS

BackgroundCells taken from mouse embryos before sex differentiation respond to insults according to their chromosomal sex, a difference traceable to differential methylation. We evaluated the mechanism for this difference in the controlled situation of their response to ethanol.MethodsWe evaluated the expression of mRNA for alcohol dehydrogenase (ADH), aldehyde dehyrogenases (ALDH), and a cytochrome P450 isoenzyme (Cyp2e1) in male and female mice, comparing the expressions to toxicity under several experimental conditions evaluating redox and other states.ResultsFemales are more sensitive to ethanol. Disulfiram, which inhibits alcohol dehydrogenase (ADH), increases cell death in males, eliminating the sex dimorphism. The expressions ADH Class 1 to 4 and ALDH Class 1 and 2 do not differ by sex. However, females express approximately 8X more message for Cyp2e1, an enzyme in the non-canonical pathway. Female cells produce approximately 15% more ROS (reactive oxygen species) than male cells, but male cells contain approximately double the concentration of GSH, a ROS scavenger. Scavenging ROS with N-acetyl cysteine reduces cell death and eliminates sex dimorphism. Finally, since many of the differences in gene expression derive from methylation of DNA, we exposed cells to the methyltransferase inhibitor 5-aza- 2-deoxycytidine; blocking methylation eliminates both the difference in expression of Cyp2e1 and cell death.ConclusionWe conclude that the sex-differential cell death caused by ethanol derives from sex dimorphic methylation of Cyp2e1 gene, resulting in generation of more ROS.