Blood Acetaldehyde Research Articles

Efficacy and Safety of Wilac L Probiotic Complex Isolated from Kimchi on the Regulation of Alcohol and Acetaldehyde Metabolism in Humans.

Alcohol-related hangovers impact both physical and mental wellness, largely due to acetaldehyde levels produced through alcohol metabolism. The present study investigated the efficacy and safety of the Wilac L probiotic complex (Levilactobacillus brevis WiKim0168 and Leuconostoc mesenteroides WiKim0172 isolated from kimchi) in improving hangovers post-alcohol consumption. This study was conducted as a randomized, double-blind, crossover placebo-controlled clinical trial from August 2023 to February 2024. Subjects (n = 26) were randomized into six test groups consuming three products, the Wilac L probiotic complex, Wilac L35 (Wilac L probiotic complex with Pyrus pyrifolia Nakai), or placebo, in different orders with crossover after a wash-out interval of 7-10 days. Blood alcohol and acetaldehyde concentrations were measured 0, 0.25, 0.5, 1, 2, 4, 6, and 15 h after alcohol consumption. The blood acetaldehyde levels measured with Wilac L probiotic complex supplementation were significantly lower than the control at 0.25 (p = 0.0381), 0.5 (p = 0.0498), and 1 h (p = 0.0260) post-consumption. The blood acetaldehyde levels after Wilac L35 consumption compared to the control are significant at 0.25 (p = 0.0115), 0.5 (p = 0.0054), 1 (p = 0.0285), 2 (p = 0.0113), and 6 h (p = 0.0287) post-consumption. No significant adverse events were reported. The Wilac L probiotic complex is associated with decreased blood acetaldehyde levels and improved subjective hangover symptoms.

Suppression of P2X4 and P2X7 by Lactobacillus rhamnosus vitaP1: effects on hangover symptoms

This study aimed to identify substances including Lactobacillus rhamnosus vitaP1 (KACC 92054P) that alleviate hangover-induced emotional anxiety and liver damage. The association between emotional anxiety caused by hangover and the genes P2X4, P2X7, SLC6A4 was investigated. In vitro and in vivo analyses were conducted to assess the influence of free-panica on alcohol-induced upregulated gene expression. Additionally, the concentration of AST, ALT, alcohol, and acetaldehyde in blood was measured. Free-panica, consisting of five natural products (Phyllanthus amarus, Phoenix dactylifera, Vitis vinifera, Zingiber officinale, and Lactobacillus rhamnosus), were evaluated for their regulatory effects on genes involved in alcohol-induced emotional anxiety and liver damage. The combination of these natural products in free-panica successfully restored emotional anxiety, and the concentration of AST, ALT, alcohol, and acetaldehyde in blood to those of the normal control group. These findings support the potential development of free-panica as a health functional food or medicinal intervention for relieving hangover symptoms and protecting liver from alcohol consumption.

Determination of a robust headspace GC-MS/MS method for analysis of ethyl alcohol and acetaldehyde: clinical application to pharmacokinetics study.

Due to the forensic aspects of drinking and exposure to toxic substances, more sophisticated quantitative technology is needed to quantify the concentration of ethyl alcohol and acetaldehyde in the blood. In this study, we developed a headspace gas chromatography tandem mass spectrometry method that could simultaneously detect ethyl alcohol and acetaldehyde in human plasma. Through a simple preparation process, ethyl alcohol and acetaldehyde were quickly detected within 4 min, and a lower limit of quantification (LLOQ) (20 and 0.2 µg/mL) was obtained; these results confirmed the suitability of the system. According to Food and Drug Administration guidelines, the linearity (correlation coefficient > 0.9996), intraday and intraday accuracy, precision, and both short- and long-term stability and freeze-thaw stability satisfied the evaluation criteria (within 100.0 ± 15.0% and 20.0% of the LLOQ). Carryover and batch size assessment for the evaluation of the sample influence during analysis also satisfied the evaluation criteria. A valid method was applied to the pharmacokinetics study, and the plasma from 43 subjects after oral administration of the placebo or HK-GCM-H01 was analyzed. The developed analysis method for ethyl alcohol and acetaldehyde in blood could be used in various fields, such as forensics and those requiring precise quantification.

Acetaldehyde-mediated increase in glutamatergic and N-acetylaspartate neurometabolite levels in the midcingulate cortex of ALDH2*1/*2 heterozygous young adults.

To elucidate the neurobiology underlying alcohol's effect on the human brain, we examined the acute effects of moderate alcohol administration on levels of glutamatergic neurometabolites and N-acetylaspartate, an amino acid found in neurons, may reflect disordered neuronal integrity. Eighteen healthy Japanese participants (7 males/11 females) aged 20-30 years who were heterozygous for an inactive allele of acetaldehyde dehydrogenase-2 (ALDH/*1/*2) were included. Participants underwent an intravenous alcohol infusion using the clamp method at a target blood alcohol concentration (BAC) of 0.50 mg/mL for 90 min within a range of ±0.05 mg/mL. We examined glutamate + glutamine (Glx) and N-acetylaspartate N-acetylaspartylglutamate (NAA) levels in the midcingulate cortex (MCC) using 3 T 1 H-MRS PRESS at baseline, 90 min, and 180 min (i.e., 90 min after alcohol infusion was finished). A two-way repeated-measures analysis of variance was used to assess longitudinal changes in Glx and NAA levels, with time and sex as within- and between-subject factors, respectively. Pearson's correlation coefficients were calculated among neurometabolite levels and BAC or blood acetaldehyde concentration (BAAC). Both Glx (F(2,32) = 8.15, p = 0.004, η2 = 0.15) and NAA (F(2,32) = 5.01, p = 0.04, η2 = 0.07) levels were increased after alcohol injection. There were no sex or time × sex interaction effects observed. NAA levels were positively correlated with BAAC at 90 min (r(13) = 0.77, p = 0.01). There were no associations between neurometabolite levels and BAC. Both Glx and NAA levels in the MCC increased in response to the administration of moderate concentrations of alcohol. Given positive associations between NAA levels and BAAC and the hypothetical glutamate release via dopamine pathways, the effects of drinking on the MCC in the acute phase may be ascribed to acetaldehyde metabolized from alcohol.

Defecation alleviates hangover by terminating intestinal drinking.

The concept of "intestinal drinking" in this study refers to the continued absorption of alcohol in the gastrointestinal tract until adequate defecation occurs. A longitudinal observation of hangover symptoms and alcohol metabolites in healthy humans following binge drinking was conducted. The hangover symptoms resulting from binge alcohol consumption were relieved by defecation. Following the defecation process, not only the blood ethanol levels, but also the concentrations of blood acetaldehyde, methanol, and iso-propanol, exhibited significant reductions. This pilot study provides a different perspective for addressing hangovers and potentially mitigating the risks of alcoholic liver diseases.

Effects of Plant-Based Extract Mixture on Alcohol Metabolism and Hangover Improvement in Humans: A Randomized, Double-Blind, Paralleled, Placebo-Controlled Clinical Trial.

Hangovers are uncomfortable physiological symptoms after alcohol consumption caused by acetaldehyde, a toxic substance in which alcohol is metabolized by alcohol dehydrogenase (ADH). Rapid alcohol and acetaldehyde decomposition are essential to alleviate alcohol handling symptoms. This study investigated the effects of HY_IPA combined with Mesembryanthemum crystallinum, Pueraria lobata flower, and Artemisia indica on alleviating hangovers. A randomized, double-blind, parallel-group, placebo-controlled clinical study was conducted on 80 individuals with hangover symptoms. Alcohol intake was 0.9 g/bw with 40% whiskey, adjusted proportionately to body weight. The Acute Hangover Scale total score was 5.24 ± 5.78 and 18.54 ± 18.50 in the HY_ IPA and placebo groups, respectively (p < 0.0001). All nine indicators of the hangover symptom questionnaire were significantly improved in the HY_IPA group (p < 0.01). Blood alcohol and acetaldehyde concentrations rapidly decreased from 30 min in the HY_IPA group (p < 0.05). ADH and acetaldehyde dehydrogenase (ALDH) activities in the blood of the HY_IPA group were significantly higher than those in the placebo group at 0, 1, and 2 h after alcohol consumption (p < 0.01). The rapid hangover relief was due to increased ADH and ALDH. Therefore, HY_IPA effectively relieves hangover symptoms by decomposing alcohol and acetaldehyde when consumed before alcohol consumption.

Hangover-Relieving Effect of Ginseng Berry Kombucha Fermented by Saccharomyces cerevisiae and Gluconobacter oxydans in Ethanol-Treated Cells and Mice Model.

This study aimed to evaluate the hangover relieving effect of ginseng berry kombucha (GBK) fermented with Saccharomyces cerevisiae and Gluconobacter oxydans in in vitro and in vivo models. The antioxidant activity and oxidative stress inhibitory effect of GBK were evaluated in ethanol-treated human liver HepG2 cells. In addition, biochemical and behavioral analyses of ethanol treated male ICR mice were performed to confirm the anti-hangover effect of GBK. The radical scavenging activity of GBK was increased by fermentation, and the total ginsenoside content of GBK was 70.24 μg/mL. In HepG2 cells, in which oxidative stress was induced using ethanol, GBK significantly increased the expression of antioxidant enzymes by upregulating the Nrf2/Keap1 pathway. Moreover, GBK (15 and 30 mg/kg) significantly reduced blood ethanol and acetaldehyde concentrations in ethanol-treated mice. GBK significantly increased the levels of alcohol-metabolizing enzymes, including alcohol dehydrogenase and acetaldehyde dehydrogenase. The balance beam test and elevated plus maze test revealed that high-dose GBK significantly ameliorated ethanol-induced behavioral changes. Collectively, GBK exerted a protective effect against ethanol-induced liver damage by regulating the Nrf2/Keap1 pathway.

Lipidomic changes of cerebral cortex in aldehyde dehydrogenase-2 knock-in heterozygote mice after chronic alcohol exposure.

Alcohol is the main legal drug in the world, and excessive consumption of alcohol seriously damages the morphological structure and function of various organs. The insufficiency of an essential enzyme in ethanol metabolism, aldehyde dehydrogenase-2 (ALDH2), will aggravate the alcohol-induced brain injury. The effect of ALDH2 after chronic alcohol exposure on global lipid profiling of the brain remains unclear. In this study, ALDH2*2 knock-in mice were fed the Lieber-DeCarli liquid diet containing ethanol for 8 weeks. Blood alcohol and acetaldehyde levels were examined, and the mice were tested through novel object recognition and the Y-maze test to evaluate cognitive impairment toward the end of the study. The lipidome profiling of cerebral cortex samples was investigated using a lipidomics method based on ultra-high performance liquid tandem chromatography quadrupole time of flight mass spectrometry (UHPLC-QTOFMS). Compared with similarly treated wild-type (WT) mice, ALDH2*2 mice exhibited poor cognitive performance, though the result did not achieve statistical significance. The lipidomics results indicated that 74 differential lipid species were selected in WT mice, of which 57 species were up-regulated, and 17 were down-regulated. Moreover, 99 differential lipids were identified in ALDH2*2 mice, of which 73 were up-regulated, and 26 were down-regulated. For ALDH2*2 mice, the number of changed significantly glycerophospholipids (GPs) subtypes was lower than that of WT mice. Interestingly, compared with WT mice, a lower proportion of polyunsaturated fatty acids (PUFAs) was found in ALDH2*2 mice. Collectively, the results provide clear evidence for a lipidomic signature of marked changes in the cerebral cortex of ALDH2*2 mice after chronic alcohol exposure. • The cerebral cortex of heterozygous ALDH2*2 mice showed more significant changes in lipidome profiles after chronic alcohol exposure than wild-type mice.• Most lipids were significantly up-regulated in both groups of mice, whereas the increase in TAG was restricted to WT mice.• For ALDH2*2 mice, GPs substances changed significantly, and SHexCer and SM subclasses in sphingolipids also deserved attention.

Aldehyde dehydrogenase 2-associated changes in pharmacokinetics, locomotor function and peripheral glutamic acid and gamma-aminobutyric acid levels during acute alcohol intoxication in male mice.

The insufficiency of human aldehyde dehydrogenase 2 (ALDH2) has been consistently associated with high blood acetaldehyde levels and impaired locomotor function during acute alcohol intoxication. The ALDH2-associated change in peripheral glutamic acid (Glu) and gamma-aminobutyric acid (GABA) levels and its correlation with pharmacokinetics and psychomotor function remain unclear. In this study, ALDH2*2 mice were used to build an acute alcohol intoxication model after intraperitoneal administration. The blood ethanol and acetaldehyde concentrations were analyzed to generate concentration-time curves at two doses of alcohol (2.0 and 4.0 g/kg). The dose of 4.0 g/kg was selected in accordance with the preliminary behavioral evaluation result to perform the following behavioral tests (e.g. the rotarod test, the open field test, and the Y-maze test), so as to assess locomotor activity, anxiety and cognitive ability. Plasma Glu and GABA levels were determined through enzyme-linked immunosorbent assays. The results suggested that the ALDH2*2 mice had highly accumulated acetaldehyde levels, impaired locomotor activity and anxiety-like emotion but unimpaired cognitive function, compared to the wild type (WT) mice. The plasma Glu level and the ratio of Glu/GABA in the alcohol-treated WT and ALDH2*2 groups decreased from 2 to 5 h after intraperitoneal administration, whereas the GABA level did not change significantly. The blood alcohol concentration in the WT and ALDH2*2 mice was positively correlated with plasma Glu level, whereas the blood acetaldehyde level was found as the opposite. We speculate that the decline degree of Glu/GABA ratio could be associated with psychomotor retardation and needs to be further investigated.

Ethanol and its Nonoxidative Metabolites Promote Acute Liver Injury by Inducing ER Stress, Adipocyte Death, and Lipolysis

Binge drinking in patients with metabolic syndrome accelerates the development of alcohol-associated liver disease. However, the underlying mechanisms remain elusive. We investigated if oxidative and nonoxidative alcohol metabolism pathways, diet-induced obesity, and adipose tissues influenced the development of acute liver injury in a single ethanol binge model. A single ethanol binge was administered to chow-fed or high-fat diet (HFD)-fed wild-type and genetically modified mice. Oral administration of a single dose of ethanol induced acute liver injury and hepatic endoplasmic reticulum (ER) stress in chow- or HFD-fed mice. Disruption of the Adh1 gene increased blood ethanol concentration and exacerbated acute ethanol-induced ER stress and liver injury in both chow-fed and HFD-fed mice, while disruption of the Aldh2 gene did not affect such hepatic injury despite high blood acetaldehyde levels. Mechanistic studies showed that alcohol, not acetaldehyde, promoted hepatic ER stress, fatty acid synthesis, and increased adipocyte death and lipolysis, contributing to acute liver injury. Increased serum fatty acid ethyl esters (FAEEs), which are formed by an enzyme-mediated esterification of ethanol with fatty acids, were detected in mice after ethanol gavage, with higher levels in Adh1 knockout mice than in wild-type mice. Deletion of the Ces1d gene in mice markedly reduced the acute ethanol-induced increase of blood FAEE levels with a slight but significant reduction of serum aminotransferase levels. Ethanol and its nonoxidative metabolites, FAEEs, not acetaldehyde, promoted acute alcohol-induced liver injury by inducing ER stress, adipocyte death, and lipolysis.

Effect of herbal extracts and supplement mixture on alcohol metabolism in Sprague Dawley-rats

This study aimed to investigate the effect of mixture of herbal extracts and supplementary formula (FNP-C) on hangovers and antioxidant enzymes in alcohol-induced liver damage in rats. HepG2 cells were used as the experimental cells and divided into five groups: non-treated control (normal), alcohol-induced control (control), mixture of herbal extracts (FNP-B), FNP-C, and a commercial treatment of liver diseases (Livers®); inhibition of detoxification and alcohol-induced damage was confirmed in vivo. Blood alcohol and acetaldehyde concentration after alcohol consumption were measured in a timely manner; alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), superoxide dismutase (SOD), glutathione (GSH), glutathione transferase (GST), and lactate dehydrogenase (LDH) levels were measured in the liver. FNP-C exhibited the highest effect. When FNP-C was administered to alcohol-induced animals, blood alcohol and acetaldehyde concentration decreased compared to FNP-B and Livers®. FNP-C reduced ADH levels and improved LDH, GSH, GST, and SOD levels. The FNP-C group was effective in preventing alcohol-induced hangovers and liver damage. Thus, FNP-C improves hangovers and increases antioxidant activity in an alcohol-induced model. Adding amino acids and vitamins to natural ingredients can potentially enhance the effect of improving hangovers.

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.

Production of Bioactive Substances to Alleviates Hangover and Ethanol-Induced Liver Damage through Fermentation of Oenanthe javanica Using Lactiplantibacillus plantarum.

The purpose of this study is to evaluate the effect of the bioconversion products of Oenanthe javanica extract fermented by Lactiplantibacillus plantarum (OEFL) on relieving hangovers and improving liver function. In addition, the bioactive substance of the OEFL, which alleviates hangover and ethanol-induced liver damage, was identified and its bioactive property was verified through in vivo experiments. In major substances analysis using high-performance liquid chromatography, OEFL produced 9.5-fold higher p-coumaric acid than the O. Javanica extract (OE). In addition, considering that quinic acid, which is not present in the OE, was produced in the OEFL it was confirmed that chlorogenic acid was decomposed into quinic acid by bioconversion. In the in vivo experiment using Sprague-Dawley rats, the OEFL and p-coumaric acid diets reduced blood ethanol, acetaldehyde, GPT, and ALP concentrations, increasing blood albumin concentrations compared to ethanol-administered groups, demonstrating that OEFL and p-coumaric acid, the main substance in the OEFL, improved ethanol-induced liver damage. Furthermore, the OEFL and its main bioactive substance, p-coumaric acid, alleviated liver fibrosis by downregulating TGF-β, SMAD-2, SMAD-4, α-SMA, and upregulating MMP-1. Therefore, OEFL is expected to be used as a functional food or pharmaceutical material as it has been confirmed to effectively relieve hangovers, prevent liver damage, and delay liver fibrosis in ethanol-induced liver damages.

NADH and NRH as potential dietary supplements or pharmacological agents for early liver injury caused by acute alcohol exposure

Alcoholism leads to many diseases, and it is also the social and economic burden of the society. Alcohol intake is the main cause of acute liver injury and chronic liver disease. Here, the ameliorative effect of NADH and dihydronicotinamide riboside (NRH) against alcohol-induced liver damage was studied and its possible mechanism was further clarified. In vitro studies showed that NADH and NRH are effective NAD+ concentration-enhancing agents. Compared with NMN, NADH and NRH can provide greater NAD+ increase at the same concentrations. Intraperitoneal injection of NADH and NRH in C57BL/6J mice also significantly increased the NAD+ content in liver, blood, brain, fat and kidney. Importantly, NADH and NRH significantly increased the liver NAD+/NADH ratio, but did not induce apoptosis markers in cells. The intragastric administration of 500 mg/kg NRH, 500 mg/kg NADH 15 min prior to acute alcohol ingestion (8 ml/kg, 40% w/v, in tap water) could dramatically enhance alcohol metabolism as revealed by the reduced concentrations of ethanol and acetaldehyde in blood as well as the decreased duration of the loss of righting reflex (LORR). Both Pretreatment and posttreatment with NADH or NRH could significantly reduce the increase of serum aspartate transaminase (AST) and alanine transaminase (ALT) after alcohol administration, indicating that they have a certain therapeutic effect on alcoholic hepatotoxicity besides preventing the adverse effects caused by alcohol. NADH and NRH could also alleviate lipid peroxidation as indicated by the repressed malondialdehyde (MDA) level and the elevated activities of superoxide dismutase (SOD) in liver tissues. Additionally, NADH or NRH can mitigate the abnormal lipid metabolism in acute alcoholic liver damage. These benefits obviously suggested that NADH or NRH could be a potential nutraceutical or pharmacological agent for promoting alcohol metabolism and preventing or treating early liver injury caused by acute alcohol exposure.

Influence of alcohol and acetaldehyde on cognitive function: findings from an alcohol clamp study in healthy young adults.

To investigate the acute effects of intravenous alcohol and its metabolite acetaldehyde on cognitive function in healthy individuals. Experimental pre-test/post-test design. Kurihama Medical and Addiction Center, Japan. A total of 298 healthy Japanese people age 20 to 24 years. Participants underwent an intravenous alcohol infusion with a target blood alcohol concentration (BAC) of 0.50 mg/mL for 180 minutes. Participants completed the continuous performance test (CPT) for sustained attention, the paced auditory serial addition test (PASAT) for working memory, and the reaction time test (RTT) for speed/accuracy, along with the blood test for BAC and blood acetaldehyde concentration (BAAC) at baseline, 60 and 180 minutes. Although the target BAC was maintained during the infusion, BAAC peaked at 30 minutes and then gradually declined (η2 = 0.18, P < 0.01). The CPT scores worsened, and the changes between 0 and 60 minutes were correlated with BAAC (correct detection, η2 = 0.09, P < 0.01; r = -0.34, P < 0.01; omission errors, η2 = 0.08, P < 0.01; r = 0.34, P < 0.01). PASAT scores improved through 180 minutes, whereas the changes between 0 and 60 minutes were negatively correlated with BAAC (task one, η2 = 0.02, P < 0.01; r = -0.25, P < 0.01; task two, η2 = 0.03, P < 0.01; r = -0.28, P < 0.01). Although RTTs worsened, they were not associated with BAC or BAAC. None of these comparisons maintained the time effect after controlling for body height. Acetaldehyde exposure following acute intravenous alcohol appears to have a negative impact on sustained attention and working memory, whereas there seems to be only a minor effect of moderate alcohol concentration on speed and accuracy.

Ethanol-Induced Hepatotoxicity and Alcohol Metabolism Regulation by GABA-Enriched Fermented Smilax china Root Extract in Rats.

Chronic alcohol consumption can cause hepatic injury and alcohol-induced toxicities. Extracts from Smilax china root have been widely used in traditional medicine and for their potential pharmacological benefits. We aimed to determine if fermented Smilax china extract (FSC) regulates alcoholic fatty liver and liver injury using two in vivo experiments. Sprague-Dawley rats were administered ethanol (3 g/kg b.w.; po) with or without FSC pretreatment to induce an acute hangover. In another experiment, rats were fed either a normal or Lieber-DeCarli ethanol (6.7%) diet with or without FSC pretreatment (125, 250, and 500 mg/kg b.w.; po) for 28 days. Serum biomarkers, liver histopathology, and the mRNA levels of anti-inflammatory, antioxidant, lipogenic, and lipolytic genes were analyzed. FSC pretreatment significantly reduced blood alcohol and acetaldehyde concentrations, upregulated the mRNA expression of alcohol dehydrogenase, aldehyde dehydrogenase, and superoxide dismutase, and decreased the activities of liver enzymes in a dose-dependent manner. It also downregulated SERBP-1c and upregulated PPAR-α and reduced the gene expression of the anti-inflammatory cytokine IL-6 in the liver. The final extract after fermentation had increased GABA content. Furthermore, FSC was found to be safe with no acute oral toxicity in female rats. Thus, FSC increases alcohol metabolism and exhibits antioxidant and anti-inflammatory effects to induce hepatoprotection against alcohol-induced damage. It may be used as a functional food ingredient after excess alcohol consumption.

Acetaldehyde Enhances Alcohol Sensitivity and Protects against Alcoholism: Evidence from Alcohol Metabolism in Subjects with Variant ALDH2*2 Gene Allele.

Alcoholism is a complex behavior trait influenced by multiple genes as well as by sociocultural factors. Alcohol metabolism is one of the biological determinants that can significantly influence drinking behaviors. Alcohol sensitivity is thought to be a behavioral trait marker for susceptibility to develop alcoholism. The subjective perceptions would be an indicator for the alcohol preference. To investigate alcohol sensitivity for the variants ADH1B*2 and ALDH2*2, sixty healthy young males with different combinatory ADH1B and ALDH2 genotypes, ADH1B*2/*2–ALDH2*1/*1 (n = 23), ADH1B*2/*2–ALDH2*1/*2 (n = 27), and ADH1B*1/*1–ALDH2*1/*1 (n = 10), participated in the study. The subjective perceptions were assessed by a structured scale, and blood ethanol and acetaldehyde were determined by GC and HPLC after an alcohol challenge in two dose sessions (0.3 g/kg or 0.5 g/kg ethanol). The principal findings are (1) dose-dependent increase of blood ethanol concentration, unaffected by ADH1B or ALDH2; (2) significant build-up of blood acetaldehyde, strikingly influenced by the ALDH2*2 gene allele and correlated with the dose of ingested alcohol; (3) the increased heart rate and subjective sensations caused by acetaldehyde accumulation in the ALDH2*2 heterozygotes; (4) no significant effect of ADH1B polymorphism in alcohol metabolism or producing the psychological responses. The study findings provide the evidence of acetaldehyde potentiating the alcohol sensitivity and feedback to self-control the drinking amount. The results indicate that ALDH2*2 plays a major role for acetaldehyde-related physiological negative responses and prove the genetic protection against development of alcoholism in East Asians.

Effects of multi-species probiotic supplementation on alcohol metabolism in rats.

Probiotics are known to protect against liver damage induced by the alcohol and acetaldehyde accumulation associated with alcohol intake. However, there have been few studies of the direct effect of probiotics on alcohol metabolism, and the types of probiotics that were previously analyzed were few in number. Here, we investigated the effects of 19 probiotic species on alcohol and acetaldehyde metabolism. Four probiotic species that had a relatively high tolerance to alcohol and metabolized alcohol and acetaldehyde effectively were identified: Lactobacillus gasseri CBT LGA1, Lactobacillus casei CBT LC5, Bifidobacterium lactis CBT BL3, and Bifidobacterium breve CBT BR3. These species also demonstrated high mRNA expression of alcohol and acetaldehyde dehydrogenases. ProAP4, a mixture of these four probiotics species and excipient, was then administered to rats for 2 weeks in advance of acute alcohol administration. The serum alcohol and acetaldehyde concentrations were significantly lower in the ProAP4-administered group than in the control and excipient groups. Thus, the administration of ProAP4, containing four probiotic species, quickly lowers blood alcohol and acetaldehyde concentrations in an alcohol and acetaldehyde dehydrogenasedependent manner. Furthermore, the serum alanine aminotransferase activity, which is indicative of liver damage, was significantly lower in the ProAP4 group than in the control group. The present findings suggest that ProAP4 may be an effective means of limiting alcohol-induced liver damage.

Intake of Lactobacillus rhamnosus GG (LGG) fermented milk before drinking alcohol reduces acetaldehyde levels and duration of flushing in drinkers with wild-type and heterozygous mutant ALDH2: a randomized, blinded crossover controlled trial.

Alcohol consumption leads to acetaldehyde accumulation, especially in people with mutant aldehyde dehydrogenase 2 gene (ALDH2). Novel strategies to promote acetaldehyde detoxification are required to prevent alcohol-related toxicity. Probiotic bacteria such as Lactobacillus rhamnosus GG (LGG) were shown to have in vitro capacity to detoxify acetaldehyde. This randomized, blinded, placebo-controlled cross-over trial investigated the effect of LGG fermented milk in people with ALDH2 polymorphisms after moderate alcohol intake. Ten healthy wild-type and ten heterozygous mutant ALDH2 Thai men were block randomized into two groups. Each group consumed a different sequence of 150 mL fermented milk containing 108 CFU mL-1 LGG and lactic-acidified milk (placebo), followed by five glasses of beer (0.4 g ethanol per kg body weight), with a one-week wash-out. Consuming LGG fermented milk before alcohol reduced areas under the response curves of blood and salivary acetaldehyde in wild-type and heterozygous mutant ALDH2 individuals (p < 0.05 and p < 0.01, respectively). Interestingly, participants with mutant ALDH2 responded better than wild-type participants for salivary acetaldehyde (90% vs. 70%, p < 0.001). Their durations of flushing were reduced when consuming LGG milk. Regardless of ALDH2 status, 105 CFU mL-1 LGG was retained in saliva at least 3.5 h after milk consumption. In conclusion, intake of LGG fermented milk before drinking alcohol reduces blood and salivary acetaldehyde levels and duration of flushing in drinkers with wild-type and heterozygous mutant ALDH2. The addition of exogenous capacity to detoxify acetaldehyde using the probiotic product could be a potential strategy to promote the alleviation of exposure to reactive and carcinogenic acetaldehyde associated with alcohol drinking in individuals with defective ALDH2 enzyme.

Increased Brain Serotonin Rather Than Increased Blood Acetaldehyde as a Common Denominator Behind Alleged Disulfiram-Like Reactions.

Several pharmaceutical agents are known to produce ethanol intolerance, which is often depicted as disulfiram-like reaction. As in the case with disulfiram, the underlying mechanism is believed to be the accumulation of acetaldehyde in the blood, due to inhibition of the hepatic aldehyde dehydrogenases, albeit this has not been confirmed in all cases by blood acetaldehyde measurements. Herein, cefamandole, cotrimoxazole, griseofulvin, procarbazine, and propranolol, which are reported to produce a disulfiram-like reaction, as well as disulfiram, were administered to Wistar rats and the hepatic activities of ethanol metabolizing enzymes along with the levels of brain monoamines were determined. Blood acetaldehyde was also evaluated after ethanol administration in rats pretreated with the abovementioned pharmaceutical products. Disulfiram, cefamandole, and procarbazine significantly increased blood acetaldehyde levels after ethanol administration, while on the contrary, cotrimoxazole, griseofulvin, and propranolol had no effect on blood acetaldehyde. Interestingly, all substances used, except disulfiram, increased the levels of brain serotonin. According to our findings, cotrimoxazole, griseofulvin, and propranolol do not produce a typical disulfiram-like reaction, because they do not increase blood acetaldehyde when given together with ethanol. On the other hand, all tested agents share the common property to enhance brain serotonin, whereas a respective effect of ethanol is well established. Hence, the ethanol intolerance produced by these agents, whether blood acetaldehyde concentration is elevated or not, could be the result of a "toxic serotonin syndrome," as in the case of the concomitant use of serotonin-active medications that provoke clinical manifestations similar to those of a disulfiram reaction.