ABSTRACT
In Europe between 30 and 50% of all liver transplantations (LTX) are done within the context of chronic end-stage alcoholic liver disease (ALD). However, post-operatively 20-25% of these patients lapse or relapse into heavy alcohol use. Thus, assessment of alcohol relapse risk before enlisting and therapeutic follow-up during and after LTX is of utmost importance. However, as yet there are enormous differences between European countries and between transplant centers, with regard to the assessment methods and criteria and the implementation of therapeutic follow-up. Only the so-called '6-month abstinence' rule is widely used. However, there are not much scientific data validating its use in predicting relapse. Thus, there is a clear need of a more homogeneous approach, which was the focus of a symposium of the European Federation of Addiction Societies during the 14th conference of the European Society for Biomedical Research on Alcoholism, 2013 (ESBRA), entitled 'Liver transplantation: A European perspective'. In a follow-up on this symposium, the authors aim to sum up the evidence of psychiatric assessment criteria and psychiatric treatment interventions relevant in the context of patient selection and patient follow-up within ALD transplantation procedures. Based upon these findings, we propose elements of a procedure that can serve as a first step toward a model of good practice regarding addiction-specialist input within the pre- and post-transplantation period.
Subject(s)
Alcoholism/prevention & control , End Stage Liver Disease/surgery , Liver Diseases, Alcoholic/surgery , Liver Transplantation , Alcoholism/complications , Alcoholism/therapy , End Stage Liver Disease/etiology , Humans , Liver Diseases, Alcoholic/etiology , Patient Selection , Recurrence , Risk Assessment , Risk FactorsABSTRACT
BACKGROUND: Phosphatidylethanol (PEth) is currently under investigation as a highly sensitive and specific marker of alcohol misuse. As its stability in blood samples has not systematically been investigated, a study was performed to determine the stability of major PEth species in spiked and authentic whole blood and also in matching dried blood spots (DBS) at different conditions. METHODS: To PEth-free blood from teetotalers, low and high concentrations of two major PEth (18:1/18:1 and 16:0/18:1) species were added chosen on the basis of concentrations determined from authentic samples which were collected from the subjects undergoing alcohol detoxification treatment. Effects of sampling (EDTA or heparinized tubes), temperature, and time (≤30 days) were investigated. Processed samples (two at each condition, respectively) were subjected to LC gradient separation using multiple reaction monitoring. Stability was assessed using the critical difference or a periodic analysis result that was within 15 % of the initial concentration. Reaction kinetics of degradation was investigated with rate constants being checked for an Arrhenius relationship. RESULTS: PEth was stable in dried blood spot (DBS) stored either at room temperature or frozen, whereas it was not stable in whole blood except in samples stored at -80 °C. Activation energies increased in the following order: spiked heparinized blood < spiked EDTA blood < authentic EDTA blood. CONCLUSIONS: PEth is a labile analyte which is predominantly degraded by hydrolysis. Only at -80 °C, stability in whole blood can be ascertained, and analysis should be performed within 30 days. EDTA should be preferred over heparin as an additive. DBS is able to stabilize PEth thus partly resolving pre-analytical difficulties of PEth measurement.
Subject(s)
Alcoholism/blood , Blood Preservation/methods , Blood Stains , Glycerophospholipids/blood , Substance Abuse Detection/methods , Anticoagulants/pharmacology , Biomarkers/blood , Case-Control Studies , Chromatography, Liquid , Edetic Acid/pharmacology , Heparin/pharmacology , Humans , Linear Models , Tandem Mass SpectrometryABSTRACT
In this case report we present a 61-year-old patient with obstructive jaundice. Bile duct obstruction was caused by a tumor at the duodenal papilla and bile flow was restored by a plastic stent. Using endoscopic ultrasound and computed tomography imaging two additional tumors of the same morphology were found in the stomach wall and the pelvic region suggesting a multilocular gastrointestinal stroma tumor (GIST). Diagnosis of GIST was confirmed cytologically from the gastric lesion. Based on typical cutaneous manifestations (café-au-lait spots, several tiny dermal neurofibromata and Lisch nodules in the iris), a thus far unidentified neurofibromatosis type I was diagnosed which is known to promote multilocular GIST formation. Tumor resection failed because of cardiac decompensation due to a Takotsubo cardiomyopathy during induction of anesthesia. The patient has been started on imatinib instead and shows so far a stable disease over 6 months.
Subject(s)
Cholestasis, Extrahepatic/diagnosis , Cholestasis, Extrahepatic/etiology , Gastrointestinal Stromal Tumors/complications , Gastrointestinal Stromal Tumors/diagnosis , Neurofibromatosis 1/complications , Neurofibromatosis 1/diagnosis , Diagnosis, Differential , False Negative Reactions , Humans , Male , Middle AgedSubject(s)
Gastroenterology/standards , Non-alcoholic Fatty Liver Disease/diagnosis , Non-alcoholic Fatty Liver Disease/prevention & control , Obesity/diagnosis , Obesity/prevention & control , Practice Guidelines as Topic , Germany , Humans , Non-alcoholic Fatty Liver Disease/etiology , Obesity/complicationsABSTRACT
We report on a 23-year-old woman who presented with elevated serum ferritin values at our department. She had undergone cataract surgery at the age of 14 and her family pedigree showed hereditary autosomal-dominant cataract. The combination of isolated hyperferritinemia with autosomal-dominant hereditary cataract led to the diagnosis of the hereditary hyperferritinemia cataract syndrome (HHCS) which we now describe in a German family for the first time. HHCS was confirmed by detection of a causal mutation at position 32 within the iron responsive element (IRE) of L-ferritin leading to a guanine to adenine exchange and the pathognomonic star-shaped cataract. This mutation interrupts the post-transcriptional control of L-ferritin. It prevents binding of the iron regulatory protein 1 (IRP1) to the 5alpha untranslated region of L-ferritin resulting in uncontrolled L-ferritin synthesis and high serum ferritin levels independent of the body iron stores. Premature cataract is eventually caused by deposition of L-ferritin crystals in the lens of the eye. Our family shows the typical autosomal-dominant inheritance of HHCS over four generations affecting a total of 17 family members. The causal mutation, star-shaped cataract and typical laboratory configuration were confirmed in five patients. Thus, in gastroenterological practice, HHCS should be added as a differential diagnosis of hyperferritinemia in Germany. Importantly, patients with HHCS can be spared from invasive diagnostics such as liver biopsy.
Subject(s)
Apoferritins/genetics , Cataract/diagnosis , Cataract/genetics , Iron Metabolism Disorders/diagnosis , Iron Metabolism Disorders/genetics , Adult , Female , Genetic Predisposition to Disease/genetics , Heterozygote , Humans , Polymorphism, Single Nucleotide/genetics , SyndromeABSTRACT
Hyperproliferation has been suggested to play a major role in bile acid-dependent colorectal tumor promotion. Effects of chronic feeding of chenodeoxycholic acid (CDC) and ursodeoxycholic acid (UDC) were tested on cell proliferation in the colon of male noninbred Wistar rats. By use of a dynamic method measuring actual rates of cell production, proliferation was modulated by both bile acids only in the proximal part of the colon. UDC feeding produced mild hyperproliferation of basal crypt cells (cell position 5-8: 7.6 +/- 2.0 vs. 3.5 +/- 1.3 cells/1,000 cells/hr--P less than .05; cell position 9-12: 18.1 +/- 10.7 vs. 10.3 +/- 2.9--P less than .05; cell position 13-16: 18.1 +/- 8.9 vs. 9.1 +/- 2.3--P less than .05). This finding reflected a characteristic compensatory response to superficial cell damage. However, CDC application did not effect cell regeneration in this crypt area but led to a striking drop of cell renewal in higher crypt cell positions (positions greater than or equal to 17), where no proliferation was detectable. These data suggest that CDC exerts its tumor-promoting effect by other means than hyperproliferation.
Subject(s)
Chenodeoxycholic Acid/administration & dosage , Colon/drug effects , Deoxycholic Acid/analogs & derivatives , Intestinal Mucosa/drug effects , Ursodeoxycholic Acid/administration & dosage , Animals , Cell Division , Chenodeoxycholic Acid/pharmacology , Colon/cytology , Intestinal Mucosa/cytology , Male , Mitotic Index , Rats , Ursodeoxycholic Acid/pharmacologyABSTRACT
Chronic ethanol ingestion in rats results in an increase in hepatic microsomal dimethylnitrosamine (DMN) demethylase activity and in an increase in hepatic microsomal activation of DMN to a mutagen. These effects of ethanol on DMN metabolism were detectable in vitro at DMN concentrations as low as 0.3 to 1 mM and as high as 100 mM. This ability of ethanol to increase the rate of DMN metabolism over such a broad range of DMN concentrations is in marked contrast to the effects of other microsomal enzyme inducers, such as phenobarbital and 3-methylcholanthrene, which increase the rate of DMN metabolism only at relatively high DMN concentrations and repress its metabolism at low DMN concentrations.
Subject(s)
Alcoholism/metabolism , Dimethylnitrosamine/metabolism , Mutagens/metabolism , Animals , Biotransformation , Dietary Carbohydrates/metabolism , Dietary Fats/metabolism , Disease Models, Animal , Enzyme Induction/drug effects , Ethanol/pharmacology , Female , Humans , Male , Microsomes, Liver/enzymology , RatsABSTRACT
Possible mechanisms whereby alcohol abuse and alcohol-related diseases may promote the development of cancer are analyzed. The mechanisms discussed include: (a) contact-related local effects on the upper gastrointestinal tract; (b) the presence of low levels of carcinogens in alcoholic beverages; (c) induction of microsomal enzymes involved in carcinogen metabolism; (d) various types of cellular injury produced by ethanol and its metabolites and their relationship to cancer, particularly in the liver; (e) the nutritional disturbances frequently associated with alcohol abuse. The relationship between alcohol-induced cirrhosis and hepatocellular carcinoma is also discussed, and case histories of patients seen at the Bronx Veterans Administration Medical Center with hepatocellular carcinoma in the absence of cirrhosis are reviewed. Data are presented demonstrating the induction, by chronic ethanol consumption, of microsomal enzymes which convert procarcinogens to carcinogens. These data were derived from experiments in which the ability of microsomes isolated from liver, intestine, and lung tissues of ethanol-fed and control rats to activate several test carcinogens was examined in the Ames Salmonella-mutagenicity test. The hypothesis is presented that ethanol-mediated induction of enzyme systems which activate procarcinogens to carcinogens in various tissues contributes to the enhanced incidence of cancer in the alcoholic.
Subject(s)
Alcoholism/complications , Neoplasms/etiology , Alcoholism/metabolism , Alcoholism/pathology , Animals , Carcinogens/metabolism , Carcinoma, Hepatocellular/etiology , Cytochrome P-450 Enzyme System/metabolism , Diet/adverse effects , Ethanol/metabolism , Fatty Liver, Alcoholic/etiology , Haplorhini , Hepatitis, Alcoholic/etiology , Humans , Intestinal Mucosa/metabolism , Liver Neoplasms/etiology , Lung/metabolism , Microsomes, Liver/metabolism , Mitochondria, Liver/ultrastructure , Mutagens/metabolism , Nutrition Disorders/complicationsABSTRACT
Aberrant de novo methylation of DNA is considered an important mediator of tumorigenesis. To investigate the role of de novo DNA methyltransferase 3a (Dnmt3a) in intestinal tumor development, we analyzed the expression of Dnmt3a in murine colon crypts, murine colon adenomas and human colorectal cancer using RNA fluorescence in situ hybridization (FISH), quantitative PCR and immunostaining. Following conditional deletion of Dnmt3a in the colon of APC((Min/+)) mice, we analyzed tumor numbers, genotype of macroadenomas and laser dissected microadenomas, global and regional DNA methylation and gene expression. Our results showed increased Dnmt3a expression in colon adenomas of APC((Min/+)) mice and human colorectal cancer samples when compared with control tissue. Interestingly, in tumor tissue, RNA FISH analysis showed highest Dnmt3a expression in Lgr5-positive stem/progenitor cells. Deletion of Dnmt3a in APC((Min/+)) mice reduced colon tumor numbers by ~40%. Remaining adenomas and microadenomas almost exclusively contained the non-recombined Dnmt3a allele; no tumors composed of the inactivated Dnmt3a allele were detected. DNA methylation was reduced at the Oct4, Nanog, Tff2 and Cdkn1c promoters and expression of the tumor-suppressor genes Tff2 and Cdkn1c was increased. In conclusion, our results show that Dnmt3a is predominantly expressed in the stem/progenitor cell compartment of tumors and that deletion of Dnmt3a inhibits the earliest stages of intestinal tumor development.
Subject(s)
Adenoma/genetics , Colorectal Neoplasms/genetics , DNA (Cytosine-5-)-Methyltransferases/genetics , DNA Methylation/genetics , Neoplastic Stem Cells/pathology , Adenoma/pathology , Animals , Cell Transformation, Neoplastic/genetics , Colon/metabolism , Colon/pathology , Colorectal Neoplasms/pathology , Cyclin-Dependent Kinase Inhibitor p57/biosynthesis , Cyclin-Dependent Kinase Inhibitor p57/genetics , DNA (Cytosine-5-)-Methyltransferases/biosynthesis , DNA Methyltransferase 3A , Gene Expression Regulation, Neoplastic , Homeodomain Proteins/genetics , Humans , In Situ Hybridization, Fluorescence , Mice , Mice, Inbred C57BL , Mice, Transgenic , Mucins/biosynthesis , Mucins/genetics , Muscle Proteins/biosynthesis , Muscle Proteins/genetics , Nanog Homeobox Protein , Octamer Transcription Factor-3/genetics , Peptides/genetics , Promoter Regions, Genetic , Real-Time Polymerase Chain Reaction , Trefoil Factor-2ABSTRACT
Various epidemiological studies have given evidence on the correlation between alcohol intake and different types of cancer, especially in the upper alimentary and respiratory tract and in the liver. This review discusses the tumour stimulating effects of ethanol associated mechanisms.
Subject(s)
Ethanol/adverse effects , Gastrointestinal Neoplasms/etiology , Animals , Carcinogens/toxicity , Epidemiologic Factors , Gastrointestinal Neoplasms/epidemiology , Gastrointestinal Neoplasms/physiopathology , Humans , Liver Neoplasms/etiology , Nitrosamines/metabolism , Rectal Neoplasms/etiologyABSTRACT
The effect of chronic ethanol consumption by rats on hepatic microsomal metabolism of the procarcinogen benzo[a]pyrene (B[a]P) was investigated both with respect to induction of microsomal arylhydrocarbon hydroxylase (AHH) activity and activation of B[a]P to a mutagen. In female rats, chronic ethanol ingestion produced a 42% increase in AHH activity (P less than 0.01), as measured in isolated microsomes, and also resulted in a significantly enhanced capacity (P less than 0.01) of these microsomes to activate B[a]P to a mutagen detectable in the Ames bacterial mutagenesis assay. Hepatic microsomes from male rats on the other hand did not exhibit any significant differences, either in AHH activity or in their capacity to activate B[a]P to a mutagen after chronic ethanol feeding.
Subject(s)
Alcoholism/metabolism , Benzopyrenes/metabolism , Microsomes, Liver/metabolism , Mutagens/metabolism , Animals , Aryl Hydrocarbon Hydroxylases/biosynthesis , Enzyme Induction , Female , Humans , Male , Rats , Rats, Inbred Strains , Sex FactorsABSTRACT
Chronic alcohol consumption is associated with an increased risk for breast cancer, even if consumed in moderate doses. Since acetaldehyde is a carcinogenic factor associated with chronic alcohol consumption, individuals with the alcohol dehydrogenase 1C*1 allele (ADH1C*1 allele) seem to be at particular risk, since this allele encodes for a rapidly ethanol metabolizing enzyme leading to increased acetaldehyde levels. Since recent epidemiological studies demonstrated an increased risk for breast cancer for individuals with the ADH1C*1 allele, we have investigated here ADH1C genotypes in moderate alcohol consumers. Furthermore, estradiols are also known risk factors for breast cancer and acute alcohol ingestion in high doses results in increased serum estradiol concentrations. Thus, in the present study, we tested the effect of low ethanol doses on estrogen serum concentrations. We analyzed the ADH1C genotype in 117 moderate alcohol consumers with breast cancer and in 111 age-matched women with alcohol associated diseases without cancer (74 cirrhotics, 22 patients with pancreatitis and 15 alcohol dependent patients). In addition, 107 healthy controls were studied. Genotyping of the ADH1C-locus was performed using polymerase chain reaction-based restriction fragment length polymorphism methods on leukocyte DNA. To study the effects of ethanol on estradiol levels, ethanol in a dose of 0.225 g/kg body weight was given orally to 8 premenopausal women at various time points of their menstrual cycle. Thereafter estradiol serum concentrations were measured over time. The allele frequency of the ADH1C*1 allele was found to be significantly increased in moderate alcohol consumers with breast cancer as compared to age-matched alcoholic controls without cancer (62% vs. 41.9%, p=0.0035). Women with the ADH1C*1,1 genotype were found to be 1.8 times more at risk for breast cancer than those with another genotype (95% CI 1.431-2.330, p<0.001). Oral ethanol increased serum estradiol levels significantly by 27-38%. The data demonstrate that moderate alcohol consumers with the ADH1C*1 allele have an increased risk to develop breast cancer and even small amounts of alcohol increase serum estradiol levels significantly in premenopausal women especially in the midphase of the menstrual cycle.
Subject(s)
Alcohol Dehydrogenase/genetics , Breast Neoplasms/etiology , Breast Neoplasms/genetics , Estradiol/blood , Ethanol/adverse effects , Polymorphism, Genetic , Adult , Aged , Female , Gene Frequency , Humans , Middle Aged , Premenopause/blood , Risk FactorsABSTRACT
Chronic alcohol consumption may lead to primary and secondary malnutrition. In particular, protein energy malnutrition not only aggravates alcoholic liver disease but also correlates with impaired liver function and increased mortality. Therefore, in these patients, adequate nutritional support should be implemented in order to improve their prognosis. Clinical trials addressing this issue have shown that nutritional therapy either enterally or parenterally improves various aspects of malnutrition, and there is increasing evidence that it may also improve survival. Therefore, malnourished alcoholics should be administered a diet rich in carbohydrate- and protein-derived calories preferentially via the oral or enteral route. Micronutrient deficiencies typically encountered in alcoholics, such as for thiamine and folate, require specific supplementation. Patients with hepatic encephalopathy may be treated with branched-chain amino acids in order to achieve a positive nitrogen balance. Fatty liver represents the early stage of alcoholic liver disease, which is usually reversible with abstinence. Metadoxine appears to improve fatty liver but confirmatory studies are necessary. S-adenosyl-L-methionine may be helpful for patients with severe alcoholic liver damage, since various mechanisms of alcohol-related hepatotoxicity are counteracted with this essential methyl group donor, while a recent large trial showed that the use of polyenylphosphatidylcholine is of limited efficacy.
Subject(s)
Liver Diseases, Alcoholic/diet therapy , Food, Formulated , Humans , Nutrition Disorders/complications , Parenteral Nutrition/methods , Prognosis , Survival AnalysisABSTRACT
Alcohol dehydrogenase (ADH) consists of a family of isozymes that convert alcohols to their corresponding aldehydes using NAD+ as a cofactor. The metabolism of ethanol by gastrointestinal ADH isozymes results in the production of acetaldehyde, a highly toxic compound that binds to cellular protein and DNA if not further metabolized to acetate by acetaldehyde dehydrogenase isozymes. Acetaldehyde seems to be involved in ethanol-associated cocarcinogenesis. The metabolism of retinol and the generation of retinoic acid is a function of class I and class IV ADH, and its inhibition by alcohol may lead to an alteration of epithelial cell differentiation and cell growth and may also be involved in ethanol-associated gastrointestinal cocarcinogenesis.
Subject(s)
Alcohol Dehydrogenase/metabolism , Digestive System/enzymology , Isoenzymes/metabolism , Acetaldehyde/metabolism , Alcohol Dehydrogenase/analysis , Animals , Carcinogens/metabolism , Ethanol/metabolism , Gastrointestinal Neoplasms/chemically induced , Humans , Isoenzymes/analysis , NAD/metabolismABSTRACT
A microsomal ethanol oxidizing system (MEOS) is present in the colonic mucosa of the rat. This MEOS metabolizes ethanol to acetaldehyde at the physiological pH of 7.4. Alcohol dehydrogenase or catalase are not involved in the reaction. The Michaelis Menten constant of the reaction is 13.7 +/- 0.3 mM and the maximal velocity is 219 +/- 30 pmoles acetaldehyde/mg microsomal protein X min. Bacterial ethanol metabolism does not contribute to the acetaldehyde production in the colonic MEOS. Chronic ethanol consumption has no effect on colonic MEOS activity. In addition, chronic ethanol ingestion does not affect colonic microsomal NADPH-cytochrome-c-reductase nor benzo(a) pyrene hydroxylase activity.
Subject(s)
Colon/metabolism , Ethanol/metabolism , Intestinal Mucosa/metabolism , Alcohol Oxidoreductases/metabolism , Animals , In Vitro Techniques , Kinetics , Male , Microsomes/enzymology , NADP/metabolism , NADPH-Ferrihemoprotein Reductase/metabolism , Oxidation-Reduction , Rats , Rats, Inbred StrainsABSTRACT
INTRODUCTION: Cells other than lymphocytes may be preferable as surrogate biomarkers during exposure monitoring. In nutritional toxicology, cells from colorectal tissues are particularly relevant for studying associations between food and cancer. Thus, we have previously shown that colonic cells of males have higher levels of DNA damage than females, which (among other factors) could be due to a higher consumption of alcoholic beverages by males. To test this hypothesis, we have performed a first exploratory study to compare DNA damage in rectal cells from biopsies of male patients with alcohol abuse and of male and female controls. Peripheral blood lymphocytes were additionally monitored to assess systemic exposure loads. METHODS: Cells were isolated and subjected to microgelelectrophoresis +/- endonuclease III to measure DNA breaks and oxidized pyrimidine bases ("comet-assay"). Cell aliquots were treated with H(2)O(2) for 5min in suspension culture and processed immediately or after 60min to determine induced damage and its persistence. RESULTS: Pooled data from subjects of all groups revealed that oxidative DNA damage in rectal cells directly correlated to damage in lymphocytes. Female controls had lower levels of DNA damage than male controls, confirming the previous studies. An unexpected result was that male alcohol abusers had significantly less genetic damage than male controls. Also, repair was detected in lymphocytes of male alcohol abusers and female controls, but not in male controls. CONCLUSION: This is the first time the comet-assay has been used to detect genotoxicity in human rectal cells as a biomonitoring tool. Our pilot study confirms earlier reports on sex differences and indicates a good correlation between damage in rectal cells and damage in lymphocytes and implies that alcohol exposure enhances endogenous defence.
Subject(s)
Alcohol Drinking , DNA Damage , Rectum/cytology , Sex Factors , Adult , Biomarkers , Comet Assay , DNA Repair , Disease Susceptibility , Female , Humans , Lymphocytes/ultrastructure , Male , Middle Aged , Pilot Projects , Rectum/ultrastructureABSTRACT
The colonic cyclic AMP system is known to be involved in intestinal secretion and can be stimulated by a variety of gastrointestinal hormones including prostaglandins. We have investigated the effect of chronic ethanol ingestion on the activity of the key enzymes in cyclic AMP metabolism--adenylate cyclase and cyclic AMP phosphodiesterase--in the colonic mucosa of the rat. Chronic ethanol consumption by feeding a nutritionally adequate liquid diet enhanced basal colonic adenylate cyclase activity significantly by 168% (p less than 0.01), but had no effect on colonic low Km cyclic AMP phosphodiesterase activity. In addition, various hormonal secretagogues were used to stimulate colonic adenylate cyclase. Colonic adenylate cyclase exhibited a significantly greater sensitivity and efficacy to prostaglandins and vasoactive intestinal peptide after chronic ethanol ingestion. Since increased intestinal cyclic AMP production due to an increased activity of intestinal adenylate cyclase is known to promote intestinal secretion of water and electrolytes, the frequently observed diarrhea in alcoholics may be explained at least in part by an enhanced production of colonic cyclic AMP.
Subject(s)
Alcoholism/enzymology , Colon/enzymology , Cyclic AMP/metabolism , Gastrointestinal Hormones/pharmacology , 3',5'-Cyclic-AMP Phosphodiesterases/metabolism , Adenylyl Cyclases/metabolism , Animals , Colon/drug effects , Dinoprostone , Epoprostenol/pharmacology , Humans , Intestinal Mucosa/drug effects , Intestinal Mucosa/enzymology , Male , Prostaglandins E/pharmacology , Rats , Rats, Inbred Strains , Vasoactive Intestinal Peptide/pharmacologyABSTRACT
The effect of chronic ethanol administration on 1,2-dimethylhydrazine induced rectal carcinogenesis was investigated in 32 paired male Sprague-Dawley rats fed a nutritionally adequate liquid diet containing 36% of total calories either as ethanol or isocaloric carbohydrates. Chronic ethanol ingestion increased the total number of rectal tumors significantly (17 vs. 6, p less than 0.02), whereas no cocarcinogenic effect of ethanol was observed in other parts of the intestine. Alcohol did not influence tumor size or histopathology. A 47% increase in the activity of mucosal alcohol dehydrogenase in the distal colorectum was found between chronically ethanol fed and pair fed controls (0.241 +/- 0.019 vs. 0.164 +/- 0.020 mumol mg protein-1 hr-1, p less than 0.01). This could in part explain the cocarcinogenic effect of alcohol in this tissue. The data give experimental support to the epidemiologic findings of an increased incidence of rectal cancer in the alcoholic.
Subject(s)
Alcoholism/complications , Cocarcinogenesis , Rectal Neoplasms/chemically induced , 1,2-Dimethylhydrazine , Alcohol Dehydrogenase , Alcohol Oxidoreductases/metabolism , Animals , Dimethylhydrazines , Humans , Intestines/pathology , Liver/enzymology , Male , Rats , Rats, Inbred Strains , Rectal Neoplasms/pathologyABSTRACT
Chronic ethanol consumption is a major risk factor for oropharyngeal, esophageal, and rectal cancer. Because hyperregenerative gastrointestinal mucosa has an increased susceptibility towards chemical carcinogens and thus influences carcinogenesis, various studies have been performed to evaluate the effect of chronic ethanol consumption on mucosal cell turnover. In the rat, morphometric analysis showed that in chronically ethanol-fed rats the size of the basal cell nuclei of the oral mucosa from the floor of the mouth, the edge of the tongue, and the base of the tongue were significantly enlarged. The size of the basal cell layer was increased and the stratification of the cells was altered. The percentage of cells in S-phase of the cell cycle was significantly higher in ethanol-fed rats compared to controls. In addition, mucosal atrophy was found. Similar to the oropharynx, in the esophagus chronic ethanol consumption increased cell proliferation depending on salivary gland function, because only in the presence of the salivary glands was this stimulative effect of alcohol on cell turnover found. Subsequently, chronic ethanol ingestion significantly stimulated crypt cell production rate in the rectum, in an age-dependent manner. This hyperregeneration, which was only observed in the rectum but not in the remaining colon, was associated with an expansion of the proliferative compartment of the crypt. Such an expansion is correlated with increased risk for rectal cancer. In addition, crypt cell production rates in the rectal crypts can be correlated with mucosal acetaldehyde concentrations, underlining a toxic effect of acetaldehyde on the rectal mucosa that is answered by compansatory hyperregeneration. These data from the rat model could be confirmed in humans. In conclusion, chronic ethanol consumption leads to mucosal hyperregeneration in gastrointestinal mucosa associated with a high risk for cancer and may therefore be at least one mechanism by which alcohol exerts its cocarcinogenic effect.
Subject(s)
Digestive System/drug effects , Ethanol/pharmacology , Neoplasms, Experimental/chemically induced , Regeneration , Alcohol Drinking , Animals , Digestive System/cytology , Ethanol/adverse effects , HumansABSTRACT
Cirrhosis of the liver is a major complication of various chronic liver diseases and results from excess production and decreased degradation of extracellular matrix. Proinflammatory cytokines, toxic metabolites and certain drugs can trigger enhanced fibrogenesis in hepatic stellate cells and myofibroblasts, the major matrix-producing cells. Since treatment of established cirrhosis is limited, therapeutic interventions that inhibit or mitigate fibrogenesis are needed. Numerous drugs have been investigated for their antifibrotic potential and botanicals constitute a significant fraction of them. Colchicine has been used to treat various chronic liver diseases with controversial results. To date, there is a lack of studies in appropriate animal models and well-controlled human trials to demonstrate its antifibrotic properties. Silymarin has so far failed to clearly show an antifibrotic effect in human studies, whereas animal experiments suggest that this mixture of flavolignanes may be beneficial in patients which have not yet developed cirrhosis. Animal studies indicate an antifibrotic potential of Shosaiko-to, a herbal combination frequently used in China and Japan for the treatment of chronic viral hepatitis, but mechanisms of action need to be further explored. Other botanicals include trans-resveratrol, a flavonoid extracted from grapevine, and Salvia miltiorrhiza which were shown to interfere with the process of hepatic stellate cell activation. Herbal combinations, such as compound 861 and LIV.52 were advocated as antifibrotics or hepatoprotectives, but studies in humans have either been of questionable design or resulted in cessation of the trial due to adverse outcomes.