Acetaldehyde induces NER repairable mutagenic DNA lesions.

Nucleotide excision repair (NER) is a repair mechanism that removes DNA lesions induced by UV radiation, environmental mutagens and carcinogens. There exists sufficient evidence against acetaldehyde suggesting it to cause a variety of DNA lesions and be carcinogenic to humans. Previously, we found that acetaldehyde induces reversible intra-strand GG crosslinks in DNA similar to those induced by cis-diammineplatinum(II) that is subsequently repaired by NER. In this study, we analysed the repairability by NER mechanism and the mutagenesis of acetaldehyde. In an in vitro reaction setup with NER-proficient and NER-deficient xeroderma pigmentosum group A (XPA) cell extracts, NER reactions were observed in the presence of XPA recombinant proteins in acetaldehyde-treated plasmids. Using an in vivo assay with living XPA cells and XPA-correcting XPA cells, the repair reactions were also observed. Additionally, it was observed that DNA polymerase eta inserted dATP opposite guanine in acetaldehyde-treated oligonucleotides, suggesting that acetaldehyde-induced GG-to-TT transversions. These findings show that acetaldehyde induces NER repairable mutagenic DNA lesions.

Non-Acid Fluid Exposure and Esophageal Squamous Cell Carcinoma.

Esophageal squamous cell carcinoma (ESCC) accounts for the large majority of esophageal cancer cases worldwide. In this review, we examine the potential role of non-acidic fluid (NAF) exposure in ESCC carcinogenesis. Esophageal NAF consists of a mixture of salivary, esophageal, gastric, and duodenal fluids, containing inflammatory constituents such as digestive enzymes and bile acids that induce DNA damage, as well as known carcinogens such as acetaldehyde and N-nitrosamines. Exposure to NAF can occur in the setting of increased non-acid reflux, decreased gastric acidity, and decreased esophageal fluid clearance. Non-acid reflux has been associated with ESCC in small observational studies, and in animal models bile reflux can promote the development of ESCC. Associations have been found between increased ESCC risk and atrophic gastritis, a history of partial gastrectomy, and proton pump inhibitor use, all of which raise the pH of refluxate. Additionally, a minimally or non-acidic gastric environment contains an altered microbiome that can increase the production of acetaldehyde and N-nitrosamines. Esophageal motility disorders such as achalasia and opioid-induced esophageal dysfunction result in increased stasis and exposure to these potentially proinflammatory constituents of NAF. NAF may promote the development of ESCC via multiple mechanisms and is an understudied area of research.

Glycolaldehyde-Derived High-Molecular-Weight Advanced Glycation End-Products Induce Cardiac Dysfunction through Structural and Functional Remodeling of Cardiomyocytes.

BACKGROUND/AIMS: High-molecular-weight advanced glycation end-products (HMW-AGEs) are abundantly present in our Western diet. There is growing evidence reporting that HMW-AGEs contribute to the development of cardiovascular dysfunction in vivo, next to the well-known low-molecular-weight AGEs. The goal of our study is to assess the ultrastructure and function of cardiomyocytes after chronic exposure to HMW-AGEs. A better understanding of underlying mechanisms is essential to create new opportunities for further research on the specific role of HMW-AGEs in the development and progression of cardiovascular diseases. METHODS: Adult male rats were randomly assigned to daily intraperitoneal injection for six weeks with either HMW-AGEs (20 mg/kg/day) or a control solution. Hemodynamic measurements were performed at sacrifice. Single cardiomyocytes from the left ventricle were obtained by enzymatic dissociation through retrograde perfusion of the aorta. Unloaded cell shortening, time to peak and time to 50% relaxation were measured during field stimulation and normalized to diastolic length. L-type Ca2+ current density (ICaL) and steady-state inactivation of ICaL were measured during whole-cell ruptured patch clamp. Myofilament functional properties were measured in membrane-permeabilized cardiomyocytes. Ultrastructural examination of cardiac tissue was performed using electron microscopy. RESULTS: Rats injected with HMW-AGEs displayed in vivo cardiac dysfunction, characterized by significant changes in left ventricular peak rate pressure rise and decline accompanied with an increased heart mass. Single cardiomyocytes isolated from the left ventricle revealed concentric hypertrophy, indicated by the increase in cellular width. Unloaded fractional cell shortening was significantly reduced in cells derived from the HMW-AGEs group and was associated with slower kinetics. Peak L-type Ca2+ current density was significantly decreased in the HMW-AGEs group.L-type Ca2+ channel availability was significantly shifted towards more negative potentials after HMW-AGEs injection. The impact of HMW-AGEs on myofilament function was measured in membrane-permeabilized cardiomyocytes showing a reduction in passive force, maximal Ca2+ activated force and rate of force development. Ultrastructural examination of cardiac tissue demonstrated adverse structural remodeling in HMW-AGEs group characterized by a disruption of the cyto-architecture, a decreased mitochondrial density and altered mitochondrial function. CONCLUSION: Our data indicate that HMW-AGEs induce structural and functional cellular remodeling via a different working mechanism as the well-known LMW-AGEs. Results of our research open the door for new strategies targeting HMW-AGEs to improve cardiac outcome.

A novel quantification method for sulfur-containing biomarkers of formaldehyde and acetaldehyde exposure in human urine and plasma samples.

A novel method for the quantification of the sulfur-containing metabolites of formaldehyde (thiazolidine carboxylic acid (TCA) and thiazolidine carbonyl glycine (TCG)) and acetaldehyde (methyl thiazolidine carboxylic acid (MTCA) and methyl thiazolidine carbonyl glycine (MTCG)) was developed and validated for human urine and plasma samples. Targeting the sulfur-containing metabolites of formaldehyde and acetaldehyde in contrast to the commonly used biomarkers formate and acetate overcomes the high intra- and inter-individual variance. Due to their involvement in various endogenous processes, formate and acetate lack the required specificity for assessing the exposure to formaldehyde and acetaldehyde, respectively. Validation was successfully performed according to FDA's Guideline for Bioanalytical Method Validation (2018), showing excellent performance with regard to accuracy, precision, and limits of quantification (LLOQ). TCA, TCG, and MTCG proved to be stable under all investigated conditions, whereas MTCA showed a depletion after 21 months. The method was applied to a set of pilot samples derived from smokers who consumed unfiltered cigarettes spiked with 13C-labeled propylene glycol and 13C-labeled glycerol. These compounds were used as potential precursors for the formation of 13C-formaldehyde and 13C-acetaldehyde during combustion. Plasma concentrations were significantly lower as compared to urine, suggesting urine as suitable matrix for a biomonitoring. A smoking-related increase of unlabeled biomarker concentrations could not be shown due to the ubiquitous distribution in the environment. While the metabolites of 13C-acetaldehyde were not detected, the described method allowed for the quantification of 13C-formaldehyde uptake from cigarette smoking by targeting the biomarkers 13C-TCA and 13C-TCG in urine.Graphical abstract.

Different Effects of Knockouts in ALDH2 and ACSS2 on Embryonic Stem Cell Differentiation.

BACKGROUND: Ethanol (EtOH) is a teratogen that causes severe birth defects, but the mechanisms by which EtOH affects stem cell differentiation are unclear. Our goal here is to examine the effects of EtOH and its metabolites, acetaldehyde (AcH) and acetate, on embryonic stem cell (ESC) differentiation. METHODS: We designed ESC lines in which aldehyde dehydrogenase (ALDH2, NCBI#11669) and acyl-CoA synthetase short-chain family member 2 (ACSS2, NCBI#60525) were knocked out by CRISPR-Cas9 technology. We selected these genes because of their key roles in EtOH oxidation in order to dissect the effects of EtOH metabolism on differentiation. RESULTS: By using kinetic assays, we confirmed that AcH is primarily oxidized by ALDH2 rather than ALDH1A2. We found increases in mRNAs of differentiation-associated genes (Hoxa1, Cyp26a1, and RARß2) upon EtOH treatment of WT and Acss2-/- ESCs, but not Aldh2-/- ESCs. The absence of ALDH2 reduced mRNAs of some pluripotency factors (Nanog, Sox2, and Klf4). Treatment of WT ESCs with AcH or 4-hydroxynonenal (4-HNE), another substrate of ALDH2, increased differentiation-associated transcripts compared to levels in untreated cells. mRNAs of genes involved in retinoic acid (RA) synthesis (Stra6 and Rdh10) were also increased by EtOH, AcH, and 4-HNE treatment. Retinoic acid receptor-γ (RARγ) is required for both EtOH- and AcH-mediated increases in Hoxa1 and Stra6, demonstrating the critical role of RA:RARγ signaling in AcH-induced ESC differentiation. CONCLUSIONS: ACSS2 knockouts showed no changes in differentiation phenotype, while pluripotency-related transcripts were decreased in ALDH2 knockout ESCs. We demonstrate that AcH increases differentiation-associated mRNAs in ESCs via RARγ.

ALDH2 and Cardiovascular Disease.

Aldehyde dehydrogenase 2 (ALDH2) is a non-cytochrome P450 mitochondrial aldehyde oxidizing enzyme. It is best known for its role in the metabolism of acetaldehyde, a common metabolite from alcohol drinking. More evidences have been accumulated in recent years to indicate a greater role of ALDH2 in the metabolism of other endogenous and exogenous aldehydes, especially lipid peroxidation-derived reactive aldehyde under oxidative stress. Many cardiovascular diseases are associated with oxidative stress and mitochondria dysfunction. Considering that an estimated 560 million East Asians carry a common ALDH2 deficient variant which causes the well-known alcohol flushing syndrome due to acetaldehyde accumulation, the importance of understanding the role of ALDH2 in these diseases should be highlighted. There are several unfavorable cardiovascular conditions that are associated with ALDH2 deficiency. This chapter reviews the function of ALDH2 in various pathological conditions of the heart in relation to aldehyde toxicity. It also highlights the importance and clinical implications of interaction between ALDH2 deficiency and alcohol drinking on cardiovascular disease among the East Asians.

Pesticide contact dermatitis in agricultural workers of Himachal Pradesh (India).

BACKGROUND: Common pesticides used in the region by agricultural workers may cause contact allergy. METHODS: Thirty agricultural workers with a history of pesticide exposure and dermatitis involving the face, neck, trunk or extremities, and 20 controls comprising 2 groups of 10 subjects each, group 1 with dermatitis and no exposure to pesticides, and group 2 with neither exposure to pesticides nor dermatitis, were patch tested with 10 pesticides commonly used in the region by use of the Finn Chamber method. RESULTS: The 30 patients, 20 of whom were male, aged 30-77 years, had dermatitis for 1 month to 18 years, with relapses and remissions. Seasonal exacerbation was present in 18 patients. Six patients attributed aggravation of their dermatitis to pesticide exposure, and 2 of these reacted positively to propiconazole. Positive patch test reactions to pesticides occurred in 10 patients, but not in controls. Thiuram was the commonest sensitizer (4 patients). Three patients were sensitized to propiconazole, and 2 patients reacted positively to metaldehyde. Formaldehyde, mercaptobenzothiazole, cypermethrin and isoproturon gave positive reactions in 1 patient each. CONCLUSION: The sensitizing potential of pesticides remains a concern. Apparently, pesticide contact dermatitis is more common than expected, but remains under-reported, as the implicated pesticides vary across regions and according to the crop patterns.

[Electronic Shiazo waterpipes: a new source of indoor air pollutants]. / Elektrische Shiazo-Wasserpfeifen: eine neue Quelle für Innenraumluftschadstoffe.

BACKGROUND: For some time, a new form of waterpipe smoking has been advertised, where steam stones moistened with aroma fluids (Shiazo) are heated electronically. Since there is no combustion of tobacco, it is often assumed that the produced vapor is not harmful to health. To clarify this issue, we performed a comprehensive inner and outer exposure assessment during the use of an electronic Shiazo waterpipe. METHODS: Three volunteers smoked an electronic waterpipe operated with nicotine-free Shiazo stones in a thoroughly ventilated room for 2 h. In three smoking sessions, three fluids with different flavorings were vaporized. In parallel, emissions of particles, volatile organic compounds, polycyclic aromatic hydrocarbons (PAH), and metals were measured in indoor air. Within a biomonitoring study, urinary metabolite profiles of air pollutants were checked. For comparison, the components of the Shiazo fluids were also analyzed. RESULTS: During the smoking sessions, concentrations of formaldehyde, acetaldehyde, glycerine, and propylene glycol rose significantly in the indoor environment. The content of putative carcinogenic PAH in indoor air increased by 42% to 174 ng/m3. Particle number concentrations ranged from 39,968 to 65,610 particles/cm3 (median), with peaks at diameters from 25 to 31 nm. 3­HPMA, the mercapturic acid metabolite of the pyrolysis product acrolein, was strongly elevated in urine samples of the smokers. All fluids contained high amounts of contact allergens. CONCLUSIONS: Electronic Shiazo waterpipes release various harmful substances that considerably impact indoor air quality. Compared to conventional waterpipes, the release of pollutants is lower. Nevertheless, smoking with Shiazo waterpipes is a source of health risks for both users and bystanders.

[Effect of interleukin-22 on proliferation and activation of hepatic stellate cells induced by acetaldehyde and related mechanism].

Objective: To investigate the effect of interleukin-22 (IL-22) on the activation and proliferation of hepatic stellate cells (HSCs) induced by acetaldehyde, as well as the role of the antioxidant axis Nrf2-keap1-ARE. Methods: Hepatic stellate cell-T6 (HSC-T6) cells were cultured in vitro, and after 24 and 48 hours of acetaldehyde stimulation at various concentrations (25, 50, 100, 200, and 400 µmol/L), MTT assay was used to measure cell proliferation rate to screen out the optimal conditions for model establishment. HSC-T6 cells were treated first with the optimal concentration of acetaldehyde (200 µmol/L) for 24 hours and then with different concentrations of IL-22 (10, 20, and 50 ng/ml) for 24 hours. MTT assay was used to measure cell proliferation, Western blot and cell immunohistochemistry were used to measure the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and α-smooth muscle actin (α-SMA), and spectrophotometry was used to measure the changes in the content of malondialdehyde (MDA) and reduced glutathione (GSH) in culture supernatant. SPSS 17.0 was used for statistical analysis and data were expressed as mean±SD. P < 0.05 was considered statistically significant. A one-way analysis of variance was used for comparison of means between any two groups. Results: HSCs had significantly enhanced proliferation and activation after being treated with acetaldehyde, especially at 200 µmol/L for 48 hours. After the intervention with gradient concentrations of IL-22, the proliferation and activation of HSCs were inhibited in a dose-dependent manner, and the proliferation and migration rates in the 10, 20, and 50 ng/ml IL-22 groups were 14%, 25%, and 35%, respectively (all P < 0.05). The results of Western blot and immunohistochemistry showed that there was no significant difference in the expression of Nrf2 total protein in HSCs between groups, while there was extremely low expression of Nrf2 nucleoprotein in the blank control group. There was increased expression of Nrf2 nucleoprotein after acetaldehyde stimulation (compared with the blank control group, P < 0.05), and after the intervention with gradient concentrations of IL-22, the expression of Nrf2 nucleoprotein was further increased (all P < 0.05). The results of spectrophotometry showed that compared with the blank control group, the model group had increased levels of MDA and GSH in culture supernatant after acetaldehyde stimulation; after the intervention with gradient concentrations of IL-22, there was a significant reduction in the MDA level and a significant increase in the GSH level in a dose-dependent manner (all P < 0.05). Conclusion: The activation and proliferation of HSCs induced by acetaldehyde helps with the successful establishment of an in vitro model of alcoholic liver fibrosis. IL-22 effectively inhibits the activation and proliferation of HSCs induced by acetaldehyde, and its mechanism may be related to promoting Nrf2 nuclear translocation in HSCs and expression of the downstream target gene GSH and increasing the activity of the antioxidant axis Nrf2-keap1-ARE.

Metabolites of Aliphatic Alcohols Detected in Alcoholic Beverages Inhibit Phagocytosis.

AIMS: The aim of our study was to measure granulocyte and monocyte phagocytosis following treatment of cells with some metabolites of aliphatic alcohols alone and in combination with acetaldehyde. METHODS: The cells were separated from human peripheral blood prior to determination of phagocytosis of opsonized zymosan particles by granulocytes and monocytes treated individually with metabolites of aliphatic alcohols including formaldehyde, 1-propanal, acetone, 1-butanal, and 2-butanone and in combination with acetaldehyde. RESULTS: The findings revealed that metabolites of aliphatic alcohols inhibited phagocytosis by granulocytes and monocytes in a concentration-dependent manner and when combined with acetaldehyde, they caused a further decrease in phagocytic activity. CONCLUSION: Due to their additive effects, it is possible that, in combination with acetaldehyde, metabolites of aliphatic alcohols may inhibit phagocytosis at physiologically realistic concentrations in episodic heavy drinkers, thereby contributing to their increased susceptibility to infectious diseases.

Carbonyl compounds in electronic cigarette vapors: effects of nicotine solvent and battery output voltage.

INTRODUCTION: Glycerin (VG) and propylene glycol (PG) are the most common nicotine solvents used in e-cigarettes (ECs). It has been shown that at high temperatures both VG and PG undergo decomposition to low molecular carbonyl compounds, including the carcinogens formaldehyde and acetaldehyde. The aim of this study was to evaluate how various product characteristics, including nicotine solvent and battery output voltage, affect the levels of carbonyls in EC vapor. METHODS: Twelve carbonyl compounds were measured in vapors from 10 commercially available nicotine solutions and from 3 control solutions composed of pure glycerin, pure propylene glycol, or a mixture of both solvents (50:50). EC battery output voltage was gradually modified from 3.2 to 4.8V. Carbonyl compounds were determined using the HPLC/DAD method. RESULTS: Formaldehyde and acetaldehyde were found in 8 of 13 samples. The amounts of formaldehyde and acetaldehyde in vapors from lower voltage EC were on average 13- and 807-fold lower than in tobacco smoke, respectively. The highest levels of carbonyls were observed in vapors generated from PG-based solutions. Increasing voltage from 3.2 to 4.8V resulted in a 4 to more than 200 times increase in formaldehyde, acetaldehyde, and acetone levels. The levels of formaldehyde in vapors from high-voltage device were in the range of levels reported in tobacco smoke. CONCLUSIONS: Vapors from EC contain toxic and carcinogenic carbonyl compounds. Both solvent and battery output voltage significantly affect levels of carbonyl compounds in EC vapors. High-voltage EC may expose users to high levels of carbonyl compounds.

Inflammatory and cytotoxic effects of acrolein, nicotine, acetylaldehyde and cigarette smoke extract on human nasal epithelial cells.

BACKGROUND: Cigarette smoke induces a pro-inflammatory response in airway epithelial cells but it is not clear which of the various chemicals contained within cigarette smoke (CS) should be regarded as predominantly responsible for these effects. We hypothesised that acrolein, nicotine and acetylaldehyde, important chemicals contained within volatile cigarette smoke in terms of inducing inflammation and causing addiction, have immunomodulatory effects in primary nasal epithelial cell cultures (PNECs). METHODS: PNECs from 19 healthy subjects were grown in submerged cultures and were incubated with acrolein, nicotine or acetylaldehyde prior to stimulation with Pseudomonas aeruginosa lipopolysaccharide (PA LPS). Experiments were repeated using cigarette smoke extract (CSE) for comparison. IL-8 was measured by ELISA, activation of NF-κB by ELISA and Western blotting, and caspase-3 activity by Western blotting. Apoptosis was evaluated using Annexin-V staining and the terminal transferase-mediated dUTP nick end-labeling (TUNEL) method. RESULTS: CSE was pro-inflammatory after a 24 h exposure and 42% of cells were apoptotic or necrotic after this exposure time. Acrolein was pro-inflammatory for the PNEC cultures (30 µM exposure for 4 h inducing a 2.0 fold increase in IL-8 release) and also increased IL-8 release after stimulation with PA LPS. In contrast, nicotine had anti-inflammatory properties (0.6 fold IL-8 release after 50 µM exposure to nicotine for 24 h), and acetylaldehyde was without effect. Acrolein and nicotine had cellular stimulatory and anti-inflammatory effects respectively, as determined by NF-κB activation. Both chemicals increased levels of cleaved caspase 3 and induced cell death. CONCLUSIONS: Acrolein is pro-inflammatory and nicotine anti-inflammatory in PNEC cultures. CSE induces cell death predominantly by apoptotic mechanisms.

Interactions of alcohol and tobacco in gastrointestinal cancer.

Cancer prevention is based on the identification of specific etiologic factors. Acetaldehyde derived from the alcoholic beverage itself and formed from ethanol endogenously has recently been classified by the International Agency for Research on Cancer/World Health Organization as a group 1 carcinogen to humans. This is based on the uniform epidemiological and biochemical evidence derived from individuals carrying alcohol and aldehyde dehydrogenase gene mutations. After drinking alcohol, these mutations are associated with increased exposure of the upper digestive tract to acetaldehyde and as well with a remarkably increased risk for upper gastrointestinal (GI) tract cancers. Acetaldehyde is the key intermediate in alcoholic fermentation and ethanol oxidation. Therefore, it is widely present in our environment. Furthermore, it is the most abundant carcinogenic compound of tobacco smoke. Most of the known risk factors for upper digestive tract cancer appear to be associated with an enhanced exposure of GI mucosa to locally formed acetaldehyde. In these process microbes, salivary glands and even mucosal cells appear to play an essential role. Consequently, in the presence of ethanol mutagenic acetaldehyde concentrations are found in the saliva, achlorhydric stomach and colon. Equal acetaldehyde concentrations are seen in saliva also during active smoking. ALDH2-deficiency and high active ADH1C result in two- to threefold salivary acetaldehyde concentrations after a dose of alcohol and this prevails for as long as ethanol is present in the blood and saliva. Regarding cancer prevention, the good news is that acetaldehyde exposure can be markedly reduced. This can be achieved by giving high priority for regulatory measures and consumer guidance.

Streptococci-human papilloma virus interaction with ethanol exposure leads to keratinocyte damage.

PURPOSE: Ethanol, human papilloma virus (HPV), and poor oral hygiene are risk factors that have been attributed to oral carcinogenesis. Streptococci sp and HPV infections are common in the head and neck, often associated with sexual activity. Although HPV is linked to head and neck squamous cell carcinoma, it is unclear whether there is a similar role for Streptococci sp. This cell study examines whether Streptococci sp and HPV-16 with exposure to ethyl alcohol (ETOH) can act as cofactors in the malignant transformation of oral keratinocytes. MATERIALS AND METHODS: ETOH (0.1%-20% vol/vol) was used to investigate Streptococci sp attachment with immortalized E6-expressing HPV/HOK-16B cells, human oral buccal keratinocytes, and foreskin keratinocytes. Streptococci sp (Streptococci mutans [LT11]) and various strains of acetaldehyde (AA) producer and nonproducer Streptococcus salivarius (110-1, 109-2, 101-7, and 107-1) and a lactic acid producer bacterium, Lactobacillus rhamnosus (24-1 and 25-2), were examined for interactions with keratinocytes by use of a green dye (percent of cells with colonies after 24 hours). Carcinogens, AA, malondialdehyde, DNA damage, and proliferation (5'-bromo-2-deoxyuridine) among keratinocytes were also quantified. RESULTS: AA and malondialdehyde production from permissible Streptococci sp significantly increased with attachment to keratinocytes, whereas L rhamnosus did not significantly attach to keratinocytes. This attachment was associated with enhanced levels of AA adduct formation, proliferation (5'-bromo-2-deoxyuridine incorporation), and enhanced migration through integrin-coated basement membrane by HPV oral keratinocytes, which are characteristics of a malignant phenotype. CONCLUSIONS: These cell studies suggest that oral Streptococci sp and HPV (HPV-16) cooperate to transform oral keratinocytes after low-level ETOH (1%) exposure. These results appear to suggest a significant clinical interaction, but further validation is warranted.

Danshensu inhibits acetaldehyde-induced proliferation and activation of hepatic stellate cell-T6.

OBJECTIVE: To evaluate the effects of danshensu, the main component of the extract of Chinese medicine Salvia miltiorrhiza, on the proliferation and activation of hepatic stellate cells (HSCs). METHODS: The activation of HSC-T6 was induced by exposure to acetaldehyde. In the meantime, different doses of danshensu were added to the culture medium. After 24 h of treatment with danshensu in acetaldehyde, the viability of HSC-T6 cells was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the cell cycle was determined through flow cytometry, and the gene transcription levels of plasminogen activator inhibitor-1 (PAI-1), transforming growth factor-ß1 (TGF-ß1), urokinase-type plasminogen activator (uPA) and matrix metalloproteinase-2 (MMP-2) were analyzed by real-time quantitative polymerase chain reaction. RESULTS: The proliferation of HSCs induced by 200 µmol/L acetaldehyde could be significantly inhibited by danshensu, and the percentage of HSCs in S phase was significantly increased as compared with the control cells (P<0.05), which were respectively evidenced by MTT assay and flow cytometry. Danshensu down-regulated the mRNA expression of TGF-ß1 and PAI-1 and up-regulated the uPA transcription level (P<0.01), while the transcription level of MMP-2 was not significantly affected in HSC-T6. CONCLUSION: Danshensu can inhibit the proliferation and activation of HSC-T6, as well as regulate some cytokines involved in extracellular matrix accumulation, which offers a potential therapeutic alternative for liver fibrosis.

Guizhi Fuling pill attenuates liver fibrosis in vitro and in vivo via inhibiting TGF-ß1/Smad2/3 and activating IFN-γ/Smad7 signaling pathways.

Liver fibrosis resulting from chronic liver injuries (CLI) is a common health problem globally. Guizhi Fuling pill (GZFL), a modern preparation from traditional Chinese medicine, exhibited anti-dysmenorrhea, anti-inflammatory, and immune-regulative effects. However, the effect of GZFL on liver fibrosis remains unknown. In this research, LX-2 cells were stimulated with acetaldehyde for mimicking liver fibrosis progression in vitro. In addition, carbon tetrachloride (CCl4)-induced mouse model of liver fibrosis was established as well. The data revealed GZFL obviously suppressed the proliferation and triggered the apoptosis of acetaldehyde-stimulated LX-2 cells. In addition, GZFL prevented acetaldehyde-induced activation of LX-2 cells via downregulation of TGF-ß1, p-Smad2, p-Smad3, CUGBP1, and upregulation of p-STAT1 and Smad7. Meanwhile, GZFL significantly alleviated CCl4­induced liver fibrosis, as evidenced by the decrease of ALT and AST levels. Moreover, GZFL downregulated the expressions of TGF-ß1, p-Smad2, p-Smad3, and CUGBP1 in CCl4-treated mice. Furthermore, GZFL remarkably elevated the levels of IFN-γ, p-STAT1, and Smad7 in CCl4-treated mice. To sum up, GZFL was able to inhibit liver fibrosis in vitro and in vivo through suppressing TGF-ß1/Smad2/3-CUGBP1 signaling and activating IFN-γ/STAT1/Smad7 signaling. Thus, GZFL might have a potential to act as a therapeutic agent for anti-fibrotic therapy.

Oxidative damage in the liver of rats treated with glycolaldehyde.

Liver diseases are often associated with hyperglycemia, inflammation, and oxidative stress. These conditions, commonly associated with diabetes mellitus and obesity, facilitate the formation of advanced glycation end products (AGEs). These products are known to impair protein function and promote inflammation. Accumulation of AGEs such as N(ε)-(carboxymethyl)lysine (CML) is related to chronic liver diseases and their severity. Although several reports suggest a crucial role of AGEs in liver failure, there is little investigation on the direct effects of reducing sugars, precursors of AGEs, and on the onset and progression of liver failure. In this work, we investigate the effects of intravenously administrated glycolaldehyde (GA), a short-chain aldehyde, on oxidative parameters in the liver of Wistar rats. Animals received a single injection of GA (10, 50, or 100 mg/kg) and were sacrificed after 6, 12, or 24 hours. Levels of protein carbonyl, lipid peroxidation, and reduced thiol were quantified. The activities of catalase, superoxide dismutase, and glyoxalase I were also assessed. The amount of CML was quantified with specific antibody. There was an increase in oxidative stress markers in the liver of GA-treated rats. Glycolaldehyde induced a decrease in the activities of all enzymes assayed. Also, all tested doses led to an increase in CML content. Our data suggest that GA might play an important role in liver diseases through the impairment of antioxidant defenses and generation of AGEs.

Alcohol consumption and the risk of breast cancer.

Epidemiologic studies addressing the association of alcohol consumption with breast cancer consistently suggest a modest association and a dose-response relationship. The epidemiologic evidence does not point to a single mechanism to explain the association, and several mechanisms have been proposed. Alcohol consumption is shown to increase levels of endogenous estrogens, known risk factors for breast cancer. This hypothesis is further supported by data showing that the alcohol-breast cancer association is limited to women with estrogen-receptor positive tumors. Products of alcohol metabolism are known to be toxic and are hypothesized to cause DNA modifications that lead to cancer. Recent research has focused on genes that influence the rate of alcohol metabolism, with genes that raise blood concentrations of acetaldehyde hypothesized to heighten breast cancer risk. Mounting evidence suggests that antioxidant intake(e.g.folate)mayreducealcohol-associatedbreast cancer risk, because it neutralizes reactive oxygen species, a second-stage product of alcohol metabolism. Diets lacking sufficient antioxidant intake, as a result, may further elevate the risk of breast cancer among alcohol consumers. Given that alcohol consumption is increasing worldwide and especially among women in countries of rapid economic growth, a greater understanding of the mechanisms underlying the known alcohol-breast cancer association is warranted. Avoiding overconsumption of alcohol is recommended, especially for women with known risk factors for breast cancer.

Alcohol and Cancer: Epidemiology and Biological Mechanisms.

Approximately 4% of cancers worldwide are caused by alcohol consumption. Drinking alcohol increases the risk of several cancer types, including cancers of the upper aerodigestive tract, liver, colorectum, and breast. In this review, we summarise the epidemiological evidence on alcohol and cancer risk and the mechanistic evidence of alcohol-mediated carcinogenesis. There are several mechanistic pathways by which the consumption of alcohol, as ethanol, is known to cause cancer, though some are still not fully understood. Ethanol's metabolite acetaldehyde can cause DNA damage and block DNA synthesis and repair, whilst both ethanol and acetaldehyde can disrupt DNA methylation. Ethanol can also induce inflammation and oxidative stress leading to lipid peroxidation and further DNA damage. One-carbon metabolism and folate levels are also impaired by ethanol. Other known mechanisms are discussed. Further understanding of the carcinogenic properties of alcohol and its metabolites will inform future research, but there is already a need for comprehensive alcohol control and cancer prevention strategies to reduce the burden of cancer attributable to alcohol.

Acetaldehyde exposure underlies functional defects in monocytes induced by excessive alcohol consumption.

Increased intestinal permeability and hepatic macrophage activation by endotoxins are involved in alcohol-induced liver injury pathogenesis. Long-term alcohol exposure conversely induces endotoxin immune tolerance; however, the precise mechanism and reversibility are unclear. Seventy-two alcohol-dependent patients with alcohol dehydrogenase-1B (ADH1B, rs1229984) and aldehyde dehydrogenase-2 (ALDH2, rs671) gene polymorphisms admitted for alcohol abstinence were enrolled. Blood and fecal samples were collected on admission and 4 weeks after alcohol cessation and were sequentially analyzed. Wild-type and ALDH2*2 transgenic mice were used to examine the effect of acetaldehyde exposure on liver immune responses. The productivity of inflammatory cytokines of peripheral CD14+ monocytes in response to LPS stimulation was significantly suppressed in alcohol dependent patients on admission relative to that in healthy controls, which was partially restored by alcohol abstinence with little impact on the gut microbiota composition. Notably, immune suppression was associated with ALDH2/ADH1B gene polymorphisms, and patients with a combination of ALDH2*1/*2 and ADH1B*2 genotypes, the most acetaldehyde-exposed group, demonstrated a deeply suppressed phenotype, suggesting a direct role of acetaldehyde. In vitro LPS and malondialdehyde-acetaldehyde adducted protein stimulation induced direct cytotoxicity on monocytes derived from healthy controls, and a second LPS stimulation suppressed the inflammatory cytokines production. Consistently, hepatic macrophages of ethanol-administered ALDH2*2 transgenic mice exhibited suppressed inflammatory cytokines production in response to LPS compared to that in wild-type mice, reinforcing the contribution of acetaldehyde to liver macrophage function. These results collectively provide new perspectives on the systemic influence of excessive alcohol consumption based on alcohol-metabolizing enzyme genetic polymorphisms.