CYP2E1 and ALDH2 Genotypes and Alcohol Dependence in Japanese

The genotypes of the CYP2E1 and ALDH2 loci of alcoholic (alcohol dependence) and nonalcoholic (healthy) Japanese were investigated to examine the relationship between the polymorphism of CYP2E1 (C₁/C₂) and ALDH2 ( ALDH2*1/ALDH2*2 ), and the susceptibility to alcoholism. There was no significant difference in C₂ gene frequency between alcoholics (0.19) and nonalcoholics (controls) (0.20), whereas there was a significant difference in ALDH2 allele frequency, suggesting that, in Japanese, the C₂ genotype of CYP2E1 may have nothing to do with the risk of developing alcohol dependence. However, the ALDH2*1 allele may influence drinking behavior and the development of alcohol dependence. Furthermore, racial interethnic differences in the frequency of the mutated allele of the CYP2E1 gene (CJ were found, like the ALDH2 gene. Japanese healthy controls showed a significantly higher frequency of the C₂ allele than did Swedish healthy controls (0.05; reported by Persson et al., FEBS Lett. 319:207-211,1993).     

Assessment of a Difference in ALDH2 Heterozygotes and Alcoholic Liver Injury

We have speculated that the degree of liver dysfunction in alcoholic liver disease with ALDH2*1/2*2 may be less pronounced than that with ALDH2*1/2*1 . In the present study, outpatients with alcoholic liver injury were examined for ALDH2 genotype and biochemical data. The number of patients was 29 cases of nonspecific changes, 16 cases of fatty liver, 5 cases of liver fibrosis, and 44 cases of liver cirrhosis. Biochemical data were evaluated with ALDH2 heterozygotes data obtained by PCR-SSCP. The ALDH2*1/2*1 and ALDH2*1/2*2 genotypes accounted for 90% and 10%, respectively. As for ALDH2*1/2*2 , there were three patients with nonspecific changes, three with fatty liver, one with liver fibrosis, and two with liver cirrhosis. In alcoholic liver disease patients, when the ALDH2*1/2*2 genotype was compared with the ALDH2*1/2*1 genotype with biochemical data, the γ-GTP value in patients with ALDH2*1/2*2 was significantly higher than with ALDH2*1/2*1 ( p < 0.005). When the frequency of ALDH2 genotype was determined in patients with alcoholic liver injury, ALDH2 heterozygotes accounted for 15% for the non-cirrhosis group, and 5% for the cirrhotic group. When a relationship between the amount of ethanol intake and biochemical data were determined in patients with alcoholic liver injury who have ALDH2 heterozygotes, the glutamic oxaloacetic transaminase (GOT) and γ-GTP values were significantly higher at an ethanol intake amount of ethanol more than 100 g per day than intake less than 100 g per day ( p < 0.05). The alcoholic patients with ALDH2*1/2*2 drink a slight amount of ethanol, the liver injury is found to be stronger than those with ALDH2*1/2*1 when they drink more than 100 g ethanol per day.     

Salivary acetaldehyde concentration according to alcoholic beverage consumed and aldehyde dehydrogenase-2 genotype

Background: Acetaldehyde is suspected of playing a critical role in cancer development in the upper aerodigestive tract (UADT). The high salivary acetaldehyde levels after alcohol drinking are partly due to acetaldehyde production by oral bacteria. Some alcoholic beverages, especially Calvados and shochu, contain very high levels of acetaldehyde. Inactive heterozygous aldehyde dehydrogenase‐2 (ALDH2) increases the risk of UADT cancer in drinkers. Methods: In a randomized cross‐over design study, 19 healthy Japanese volunteers ingested 0.6 g ethanol/kg body weight in the form of 13% ethanol Calvados, 13% ethanol shochu, 13% ethanol red wine, and 5% ethanol beer under the fasting conditions at 3‐week intervals. We monitored blood and salivary acetaldehyde concentrations immediately after drinking, and 30, 60, 90, 120, and 180 minutes after completion of drinking. Results: The acetaldehyde concentration of each beverage was: Calvados 0.60 mM (1.86 mM in 40% undiluted solution), shochu 0.60 mM (1.16 mM in 25% undiluted solution), red wine 0.25 mM, and beer 0.14 mM. The salivary acetaldehyde concentration immediately after drinking wine was significantly lower than the other beverages, and it was significantly lower immediately after drinking beer than Calvados. The acetaldehyde concentrations 30 to 180 minutes after drinking were unrelated to the beverage type. Throughout the observation period the salivary acetaldehyde concentrations were much higher than the blood acetaldehyde concentrations in all 12 active ALDH2 homozygotes (24 to 53 μM in saliva vs. 2 to 5 μM in blood) and in all 7 inactive ALDH2 heterozygotes (37 to 76 μM in saliva vs. 12 to 25 μM in blood), and they were 13 to 25 μM higher in the ALDH2 heterozygotes than in the ALDH2 homozygotes after adjusting for age, body weight, sex, smoking and drinking habits, and time since the last toothbrushing. The values after subtracting the blood acetaldehyde concentration from the salivary acetaldehyde concentration were also higher in the ALDH2 heterozygotes than in the ALDH2 homozygotes. Conclusions: There are differences in exposure of the UADT to high salivary acetaldehyde concentrations according to the type of alcoholic beverage and ALDH2 genotype, and the differences partly explain the differences in the cancer susceptibility of the UADT according to alcoholic beverage and ALDH2 genotype.     

Genetic polymorphisms of ADH2, ADH3, CYP4502E1 Dra-I and Pst-I, and ALDH2 in Spanish men: lack of association with alcoholism and alcoholic liver disease

BACKGROUND/AIMS: The relationship between polymorphisms at the alcohol dehydrogenase 2 (ADH(2)), ADH(3), CYP(450)2E1 and aldehyde dehydrogenase 2 (ALDH(2)) loci and the individual predisposition to alcoholism and alcoholic liver disease in Caucasians is controversial. METHODS: We determined the genotypes of ADH(2), ADH(3), CYP(450)2E1 (Pst-I and Dra-I) and ALDH(2) in 519 male Spaniards: 264 alcoholic subjects (47 without liver disease, 118 with non-cirrhotic liver disease and 99 with cirrhosis) and 255 non-alcoholic subjects (64 healthy controls, 110 with non-cirrhotic non-alcoholic liver disease and 81 with cirrhosis unrelated to alcohol). Genotyping was performed using PCR-RFLP methods on white cell DNA. RESULTS: The distribution of the allelic variants (allele *1 and allele *2) in the whole subjects analyzed was: ADH(2) 93.1% and 6.9%; ADH(3) 55.7 and 44.3%; CYP(450)2E1 Dra-I 11.2 and 88.8%; CYP(450)2E1 Pst-I 96.2 and 3.8% and ALDH2 100 and 0%, respectively. No differences were observed in the allelic distributions of the alcoholic and non-alcoholic subjects for the loci examined. Allele distribution in alcoholics with no liver disease, with alcoholic steatosis or hepatitis, and with cirrhosis was also similar. CONCLUSIONS: ADH(2), ADH(3), and CYP(450)2E1 Pst-I and Dra-I genetic variations are not related to alcoholism or susceptibility to alcoholic liver disease in our male population. ALDH(2) locus is monomorphic.     

Genetic polymorphisms in cytochrome P4502E1, alcohol and aldehyde dehydrogenases and the risk of esophageal squamous cell carcinoma in Gansu Chinese males

AIM：To evaluate the association between genetic polymorphisms in CYP2E1, ALDH2 and ADH1B and the risk of esophageal squamous cell carcinoma （ESCC） in a high risk area of Gansu Province, in Chinese males.
METHODS： A case-control study was conducted to investigate the genetic polymorphisms of these enzymes （CYP2E1 ＊c1/＊c2, ALDH2 ＊1/＊2 and ADH1B ＊1/＊1 genotypes）. A total of 80 esophageal cancer cases and 480 controls were recruited.
RESULTS： Compared with controls, cases had a greater prevalence of heavier alcohol consumption （53.8% vs 16.2%） and a higher proportion of alcohol drinkers with 〉 30 drink-years （28.8% vs 13.5%）. Heavier alcohol consumption and alcohol drinking with 〉 30 drink- years increased the risk of ESCC, with ORs （95% CI） of 3.20 （1.32-9.65） and 1.68 （0.96-3.21）. CYP2E1 （＊c1/＊c1）, ALDH2 （＊1/＊2） and ADH1B （＊1/＊1） genotype frequencies were higher among patients with squamous cell carcinomas, at a level close to statistical significance （P = 0.014; P = 0.094; P = 0.0001 respectively）. There were synergistic interactions among alcohol drinking and ALDH2, ADH1B and CYP2E1 genotypes. The risk of the ESCC in moderate-to-heavy drinkers with an inactive ALDH2 encoded by ALDH2 ＊1/＊2 as well as ADH1B encoded by ADH1B ＊1/＊1 and CYP2E1 encoded by CYP2E1 ＊c1/＊c1 was higher than that in the never/rare-to-light drinkers with an active ALDH2 （＊1/＊1 genotype） as well as ADH1B （＊1/＊2 ＋ ＊2/＊2） and CYP2E1 （＊c1/＊c2 ＋ ＊c2/＊c2） genotypes, with a statistically significant difference; ORs （95% CI） of 8.58 （3.28-22.68）, 27.12 （8.52-70.19） and 7.64 （2.82-11.31） respectively. The risk of the ESCC in moderate-to-heavy drinkers with ALDH2 （＊1/＊2） combined the ADH1B （＊1/＊1） genotype or ALDH2 （＊1/＊2） combined the CYP2E1 （＊c1/＊c1） genotype leads to synergistic interactions, higher than drinkers with ALDH2 （＊1/＊1） ＋ ADH1B （＊1/＊2 ＋ ＊2/＊     

Acetaldehyde Metabolism in Different Aldehyde Dehydrogenase-2 Genotypes

In order to clarify the relationships between acetaldehyde (Ac-CHO) metabolism and low Km (mitochondrial) aldehyde dehydrogenase (ALDH2) genotypes, hepatic ALDH2 activity was determined and serial changes of blood Ac-CHO levels after ethanol administration were analyzed in the individuals homozygous for the normal ALDH2 genes, heterozygous for the normal and mutant ALDH2 genes, and homozygous for the mutant ALDH2 genes. Genomic DNA was extracted from white blood cells and genotyping of ALDH2 was performed using the polymerase chain reaction technique and slot blot hybridization with synthesized oligonucleotide probes specific to the normal and mutant ALDH2 genes. ALDH2 activity was not detectable in the liver in two cases of the mutant homozygote. In four out of eight cases of the heterozygote, hepatic ALDH2 activity was measurable, although the activity was lower compared with that in the normal homozygote. Blood ethanol levels after alcohol administration were not different among the three different ALDH2 genotypes. Blood Ac-CHO levels after drinking of alcohol were significantly higher in the heterozygotes and the mutant homozygotes than in the normal homozygotes. The levels after a moderate amount of ethanol (0.8 g/kg of body weight) in a case of the mutant homozygote were not different from those of the heterozygotes. However, the levels after a small amount of ethanol (0.1 g/kg of body weight) were significantly higher in the mutant homozygotes than in the heterozygotes. These results indicate that hepatic ALDH2 activity is lacking completely, and metabolism of Ac-CHO in the liver is severely impaired in the homozygotes of the mutant ALDH2 genes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Polymorphism of Alcohol-Metabolizing Genes Affects Drinking Behavior and Alcoholic Liver Disease in Japanese Men

Alcohol is known to be mainly metabolized in the liver by alcohol dehydrogenase 2 (ADH2) and aldehyde dehydrogenase 2 (ALDH2), and cytochrome P-45011EI. The purpose of this study was to clarify the role of polymorphism of these ethanol-metabolizing enzymes in drinking behavior and the progression of alcoholic liver disease among Japanese men. Polymorphism of the ADH2, ALDH2, and P-45011EI genes was determined by polymerase chain reaction, followed by restriction fragment-length polymorphism analysis in 189 normal Japanese men and 26 male patients with alcoholic liver disease. Drinking behavior was estimated by self-assessment according to DSM-Ill-R criteria. Facial flushing was reported in 91 subjects heterozygous for ALDH2*1/*2 and in two subjects homozygous for ALDH2*2/*2, but was not found in 96 subjects homozygous for ALDH2*1/*1. In contrast, polymorphism of ADH2 and P-45011EI did not differ between flushers and nonflushers. Although the flushers only drank a small amount of alcohol (<20 g of ethanoVday), the nonflushers were divided into a group of moderate drinkers (20 to 80 glday; n = 54) and a group of heavy drinkers (780 g/day; n = 42). A high preponderance of heterozygosity for the ADH2*1/*2 genes (29/ 42; 69%) and a high frequency of the ADH2*1 allele were found in heavy drinkers, compared with moderate drinkers. However, cytochrome P-45011EI gene polymorphism was similar among the moderate and heavy drinkers. Not only a high frequency of the ALDHPl and ADH2*1 alleles, but also a high frequency of the P-45011EI c2 allele was found in the patients with alcoholic liver disease. From these results, the drinking behavior of Japanese men is strongly influenced by the ALDH2*l allele, and the level of alcohol intake is affected by the ADH2*1 allele, but not by cytochrome P-45011EI. However, progression to alcoholic liver disease among heavy drinkers may be affected by the cytochrome P-45011EI c2 allele.     

Genetic polymorphism of CYP2E1 and digestive tract alcohol damage among Polish individuals

BACKGROUND: Genetic polymorphism of enzymes involved in alcohol metabolism plays a relevant role in etiopathogenesis of alcohol disease. The aim of the present study was to find in the Polish population the CYP2E1 genotypes that are likely to be responsible for higher susceptibility to alcohol disease of the liver and chronic alcohol pancreatitis. METHODS: The CYP2E1 genotype and c1 and c2 alleles frequency were examined in 198 patients. Genotyping of the CYP2E1 was performed using polymerase chain reaction-restriction fragment length polymorphism methods on white cell DNA. RESULTS: In the examined population encompassing 198 subjects, the c2 allele was present only in 1.5% of patients. It was found only in patients abusing alcohol. In the group of patients with alcoholic cirrhosis, it was present in 3.5% of cases, whereas in patients with chronic alcoholic pancreatitis, in 2.3%. The genotype c1/c2 was present in 3% of subjects. The genotype c2/c2 was not found in any patient. Heterozygotes c1/c2 were present only in patients consuming excessive amounts of ethanol; in 7% of patients with alcoholic cirrhosis and in 4.5% of those with chronic alcoholic pancreatitis. The c2 allele occurred only in men. None of the examined women had the genotype c1/c2. CONCLUSIONS: Our studies suggest that the frequency of the c2 alleles in Polish population is low. Because of their rare frequency, it is difficult to conclude explicitly that the presence of the c2 allele promotes alcoholic damage to alimentary organs among Poles. It seems, however, that they pose the risk of alcoholic cirrhosis; their role in chronic alcoholic pancreatitis is difficult to assess.     

Genetic differences in ethanol metabolizing enzymes and blood pressure in Japanese alcohol consumers

Orientals have unique genetic polymorphisms in ethanol metabolizing enzymes, such as alcohol dehydrogenase-2 (ADH2), aldehyde dehydrogenase-2 (ALDH2) and cytochrome P450-2E1 (CYP2E1). Of the three studies conducted to clarify the influence of ALDH2 genotypes on sensitivity to the pressor effects of alcohol in Japanese, only one was suggested, though indirectly, higher sensitivity in drinkers having the genotype of inactive ALDH2. This discrepancy prompted us to determine ADH2, ALDH2 and CYP2E1 genotypes in the genomic DNA extracted from white blood cells of 855 healthy middle-aged Japanese men, and to analyse the associations with the alcohol-blood pressure (BP) relationship. No marked differences were found in the relationship among the genotypes of ALDH2, although the subjects with intact ALDH2 showed a slightly higher BP than those with inactive ALDH2 probably due to under-reporting of alcohol consumption in those with intact ALDH2 who could thus drink more. No significant influence of ADH2 genotypes was observed. A higher BP was noted in large volume alcohol consumers having c2/c2 genotype of CYP2E1. Multivariate regression analysis adjusting for the effects of age, body mass index and the volume of alcohol consumed, all of which are strong determinants of BP levels, showed only a marginal effect of c2 allele of CYP2E1 on diastolic BP elevations with increases in alcohol consumption. Thus it is concluded that the genetic polymorphisms in ethanol-metabolizing enzymes do not greatly influence the alcohol-BP relationship in Japanese men.     

Genetic polymorphisms of alcohol-metabolizing enzymes and cytokines in patients with alcohol induced pancreatitis and alcoholic liver cirrhosis]

BACKGROUND/AIMS: Susceptibility to organ damage induced by alcohol may be related to inherited variations (polymorphisms) in alcohol-metabolizing enzymes, or polymorphisms affecting cytokines. The aim of this study was to compare the genotype and allelic frequencies of ADH2, ADH3, ALDH2, cytochrome P450-2E1, IL-1, IL-6, IL-8 and tumor necrosis factor-alpha in patients with alcoholic pancreatitis and alcoholic liver cirrhosis with those of controls. METHODS: We determined the polymorphism of genes of the above-mentioned alcohol-metabolizing enzymes and cytokines in 29 alcoholic pancreatitis patients (AP), 22 alcoholic liver cirrhosis patients (LC) and 100 healthy blood donors (control). The genotypes were characterized by restriction fragment length polymorphism after amplification of genomic DNA by polymerase chain reaction. RESULTS: The allelic frequency of CYP2E1*c2 was significantly different in three groups (AP: LC: Control=0.224: 0.136: 0.320, p<0.05). There was no significant difference in the other genotypes or allelic frequencies of the three groups. The allelic frequencies of CYP2E1*c2 and ALDH2*2 were more frequent in the control than patients with alcoholic liver cirrhosis (LC: Control=0.136: 0.320, p<0.05, LC: Control= 0.114: 0.265, p<0.05). Allelic frequencies of ADH2 was statistically different between LC and control (ADH2*1; LC: Control=0.727: 0.495, ADH2*2; 0.227: 0.360, ADH2*3; 0.046: 0.145, p<0.05). CONCLUSIONS: There was no difference in the frequencies of genotype and allele of enzymes and cytokines among the three groups. However, frequency of ADH2*1 was significantly higher and those of CYP2E1*c2 and ALDH2*2 were significantly lower than LC group than control.     

Alcoholic liver disease in heterozygotes of mutant and normal aldehyde dehydrogenase-2 genes

To clarify the pathogenetic role of acetaldehyde in the development of alcoholic liver disease, genotyping of aldehyde dehydrogenase-2 genes was performed and the clinical features of the alcoholic liver disease patients with different genotypes were compared. Genotyping of aldehyde dehydrogenase-2 was performed in 47 patients with alcoholic liver disease using the polymerase chain reaction and slot-blot hybridization. Of the 47 patients with alcoholic liver disease, 40 were homozygous for the normal aldehyde dehydrogenase-2 gene and the remaining seven cases were heterozygous for the normal and mutant aldehyde dehydrogenase-2 genes. No homozygote was found for the mutant aldehyde dehydrogenase-2 genes. Daily alcohol intake was less than 100 gm in all heterozygotes without relation to the type of alcoholic liver disease. On the other hand, all but four patients homozygotic for the normal aldehyde dehydrogenase-2 gene drank more than 100 gm alcohol/day. The mean daily alcohol intake in the heterozygotes was significantly lower than that in the normal homozygotes. The incidence of alcoholic fibrosis tended to be lower in the heterozygotes than in the normal homozygotes (14.2% vs. 52.5%). On the other hand, the incidence of alcoholic hepatitis and/or cirrhosis tended to be higher in the heterozygotes than in the normal homozygotes. These results indicate that alcoholic liver disease develops even with moderate amounts of alcohol intake in heterozygotes of the aldehyde dehydrogenase-2 genes, in which acetaldehyde metabolism in the liver is impaired and liver damage in the heterozygotes is more severe than that in the normal homozygotes, suggesting that habitual drinkers who are heterozygotes of the aldehyde dehydrogenase-2 genes may be at high risk for alcoholic liver disease.     

Genotyping of the aldehyde dehydrogenase 2 (ALDH2) gene using the polymerase chain reaction: Evidence for single point mutation in the ALDH2 gene of ALDH2-deficiency

About half of all Japanese lack the activity of aldehyde dehydrogenase 2 (ALDH2), and suffer a flush after alcohol intake due to the marked elevation of blood acetaldehyde concentration. The cause of ALDH2 deficiency is thought to be a single point mutation in codon 487 of the ALDH2 gene. However, this mutant ALDH2 gene has not yet been cloned and sequenced. We amplified and cloned the exon 12 of the ALDH2 gene using polymerase chain reaction (PCR), and revealed that normal GAA coding glutamic acid is replaced for AAA coding lysine in codon 487 of the mutant ALDH2 gene. Based on this finding, we performed the genotyping of the ALDH2 gene using PCR and allele-specific oligonucleotide probes. The genotypes of 13 subjects with ALDH2-active phenotype were all homozygous for the normal ALDH2 gene (ALDH2¹), while in 9 subjects with ALDH2-deficient phenotype 2 subjects were homozygous for the mutant ALDH2 gene (ALDH2²) and the other 7 subjects were heterozygous for both genes, indicating that the mutant ALDH2 gene is dominant. In 20 normal control subjects, the prevalence of ALDH2VALDH2¹, ALDH2VALDH2² and ALDH2²/ALDH2² was 45%, 45% and 10% respectively. On the other hand, in 36 alcoholic liver disease patients, the prevalence of the genotypes was 83%, 17% and 0%. These results confirmed the previous observation that the incidence of ALDH2 deficiency is much lower in alcoholic liver disease patients than in the general population, and suggested that most of the ALDH2 deficient patients with alcoholic liver disease are heterozygous for the normal and mutant ALDH2 genes.     

Self-Reported Alcohol-Associated Symptoms and Drinking Behavior in Three ALDH2 Genotypes Among Japanese University Students

BACKGROUND: Alcohol abuse is one of the most serious health problems among young adults. Nearly half of the Japanese population is sensitive to alcohol due to a genetic polymorphism in low K(m) aldehyde dehydrogenase (ALDH2). In the present study, we investigated the effects of the ALDH2 genotype on both self-reported alcohol-associated symptoms and alcohol drinking behavior among Japanese university students. METHODS: The study subjects were 423 (389 males and 34 females) university students in a medical university. The subjects completed a questionnaire regarding self-reported alcohol-associated symptoms and alcohol drinking behavior. The ALDH2 genotype was determined through digestion of polymerase chain reaction (PCR) products by a restriction enzyme Ksp632I. The frequency of alcohol-associated symptoms generally increased in the order ALDH2*1/*1, ALDH2*1/*2, ALDH2*2/*2 among males. The frequency of those who drink > or = 5 days/week was less than 10% in all genotype groups. However, the frequency of those who drink 1-4 days/week was significantly higher in ALDH2*1/*1 than that in ALDH2*1/*2 and in ALDH2*2/*2. A similar tendency also was observed in females. Mean amounts of alcohol consumption per occasion in the three ALDH2 genotypes stratified by drinking frequency generally increased significantly in the order ALDH2*2/*2, ALDH2*1/*2, ALDH2*1/*1 in both sexes. The proportion of binge drinkers defined by those who drink ethanol of > or = 75 ml per occasion on average also increased in the order ALDH2*2/*2 (0.0%), ALDH2*1/*2 (9.8%), ALDH2*1/*1 (22.1%) among male drinkers (> or = 1 day/month). CONCLUSIONS: We for the first time demonstrated clear associations between the ALDH2 genotype, self-reported alcohol-associated symptoms, and alcohol drinking behavior among Japanese university students.     

CYP2E1 Rsa Ⅰ polymorphism impacts on risk of colorectal cancer association with smoking and alcohol drinking

AIM： To investigate associations between the Rsa I polymorphism of CYP2E1 and risk of colorectal cancer. METHODS： A case-control study was conducted with 315 colorectal cancer cases （105 colon, 210 rectal） and 439 population-based controls in Jiangsu Province of China. Genomic DNA samples were assayed for restriction fragment length polymorphisms in CYP2E1 by PCR amplification followed by digestion with Rsa I. Information on smoking and alcohol drinking was collected using a questionnaire. Odds ratios （ORs） were estimated with an unconditional logistic model. RESULTS： The proportional distribution of the CYP2E1 Rsa I c1/c1, c1/c2 and c2/c2 genotypes were 61.4%, 35.6% and 3.0% in controls, 60.6%, 33.7% and 5.8% in colon cancer cases, and 58.4%, 34.0% and 7.7% in rectal cancer cases, respectively. A significant differencewas noted between controls and rectal cancer cases （P = 0.029）, the c2/c2 genotype being associated with elevated OR （adjusted age, sex and status of the smoking and alcohol drinking） for rectal cancer （1.64, 95% CI, 1.12-2.41, vs cl allele carriers）, but not for colon cancer. In interaction analysis between the CYP2E1 Rsa I genotype and smoking and drinking habits, we found a significant cooperative action between the c2/c2 genotype and alcohol drinking in the sex-, age-adjusted ORs for both colon （4.74, 95% CI, 1.10-20.40） and rectal （5.75, 95% CI, 1.65-20.05） cancers. Among nonsmokers, the CYP2E1 Rsa I c2/c2 genotype was also associated with elevated ORs in the two sites （1.95, 95% CI, 0.99-3.86 and 2.30, 95% CI, 1.32-3.99）. CONCLUSION： The results of the present study suggest that the CYP2E1 c2/c2 genotype increases susceptibility to rectal cancer and the gene-environmental interactions between the CYP2E1 polymorphism and smoking or alcohol drinking exist for colorectal neoplasia in general.     

CYP2E1 Rsa Ⅰ polymorphism impacts on risk of colorectal cancer association with smoking and alcohol drinking

AIM: To investigate associations between the Rsa Ⅰpolymorphism of CYP2E1 and risk of colorectal cancer.METHODS: A case-control study was conducted with 315 colorectal cancer cases (105 colon, 210 rectal)and 439 population-based controls in Jiangsu Province of China. Genomic DNA samples were assayed for restriction fragment length polymorphisms in CYP2E1by PCR amplification followed by digestion with Rsa Ⅰ. Information on smoking and alcohol drinking was collected using a questionnaire. Odds ratios (ORs) were estimated with an unconditional logistic model.RESULTS: The proportional distribution of the CYP2E1 Rsa Ⅰ c1/c1, c1/c2 and c2/c2 genotypes were 61.4%,35.6% and 3.0% in controls, 60.6%, 33.7% and 5.8%in colon cancer cases, and 58.4%, 34.0% and 7.7% in rectal cancer cases, respectively. A significant difference was noted between controls and rectal cancer cases (P = 0.029), the c2/c2 genotype being associated with elevated OR (adjusted age, sex and status of the smoking and alcohol drinking) for rectal cancer (1.64,95% CI, 1.12-2.41, vs c1 allele carriers), but not for colon cancer. In interaction analysis between the CYP2E1Rsa Ⅰ genotype and smoking and drinking habits, we found a significant cooperative action between the c2/c2 genotype and alcohol drinking in the sex-, age-adjusted ORs for both colon (4.74, 95% CI, 1.10-20.40) and rectal (5.75, 95% CI, 1.65-20.05) cancers. Among nonsmokers, the CYP2E1 Rsa Ⅰ c2/c2 genotype was also associated with elevated ORs in the two sites (1.95, 95%CI, 0.99-3.86 and 2.30, 95% CI, 1.32-3.99).CONCLUSION: The results of the present study suggest that the CYP2E1 c2/c2 genotype increases susceptibility to rectal cancer and the gene-environmental interactions between the CYP2E1 polymorphism and smoking or alcohol drinking exist for colorectal neoplasia in general.     

Hangover susceptibility in relation to aldehyde dehydrogenase-2 genotype, alcohol flushing, and mean corpuscular volume in Japanese workers

BACKGROUND: A study of Asian-American students suggested a positive association between inactive ALDH2*2 and susceptibility to hangover. A biomarker for moderate-to-heavy drinking in persons with inactive aldehyde dehydrogenase-2 (ALDH2) is increased mean corpuscular volume (MCV). METHODS: Associations between hangover and ALDH2 genotype, alcohol flushing, and MCV were examined for 251 Japanese workers (139 men, 112 women). RESULTS: Inactive ALDH2*1/2*2 heterozygotes drank less alcohol than active ALDH2*1/2*1 homozygotes (p < 0.0001), but the frequency of hangover did not significantly differ between the two groups for either gender. The amount of drinking reported to lead to hangover was significantly less for male and female ALDH2*1/2*2 heterozygotes than for their ALDH2*1/2*1 homozygous counterparts (p < 0.005). The proportion of men who had hangover three times or more during the past year increased significantly with increased daily alcohol consumption in men with the ALDH2*1/2*2 genotype (p = 0.0002) but not in those with the ALDH2*1/2*1 genotype. For men who usually consumed <44 g of ethanol/day, the median amount of drinking before hangover was significantly lower for ALDH2*1/2*2 men than for ALDH2*1/2*1 men reporting the same level of consumption. Hangover occurred with consistently high frequency among ALDH2*1/2*1 men, regardless of their daily consumption. Similar findings were observed in a comparison of men who never flushed and those who reported current or former flushing, a surrogate marker of inactive ALDH2. Assessment of hangover risk by quartiles of MCV showed that men with MCV of > or =96 had a significantly higher risk of hangover than did men with MCV of <91 (odds ratio = 5.56; 95% confidence interval = 1.69-18.25). CONCLUSIONS: Inactive heterozygous ALDH2, alcohol flushing, and increased MCV were positively associated with hangover susceptibility in Japanese workers, suggesting that acetaldehyde is etiologically linked to the development of hangover.     

Genotyping of the aldehyde dehydrogenase 2 (ALDH2) gene using the polymerase chain reaction: evidence for single point mutation in the ALDH2 gene of ALDH2-deficiency

About half of all Japanese lack the activity of aldehyde dehydrogenase 2 (ALDH2), and suffer a flush after alcohol intake due to the marked elevation of blood acetaldehyde concentration. The cause of ALDH2 deficiency is thought to be a single point mutation in codon 487 of the ALDH2 gene. However, this mutant ALDH2 gene has not yet been cloned and sequenced. We amplified and cloned the exon 12 of the ALDH2 gene using polymerase chain reaction (PCR), and revealed that normal GAA coding glutamic acid is replaced for AAA coding lysine in codon 487 of the mutant ALDH2 gene. Based on this finding, we performed the genotyping of the ALDH2 gene using PCR and allele-specific oligonucleotide probes. The genotypes of 13 subjects with ALDH2-active phenotype were all homozygous for the normal ALDH2 gene (ALDH2(1)), while in 9 subjects with ALDH2-deficient phenotype 2 subjects were homozygous for the mutant ALDH2 gene (ALDH2(2)) and the other 7 subjects were heterozygous for both genes, indicating that the mutant ALDH2 gene is dominant. In 20 normal control subjects, the prevalence of ALDH2(1)/ALDH2(1), ALDH2(1)/ALDH2(2) and ALDH2(2)/ALDH2(2) was 45%, 45% and 10% respectively. On the other hand, in 36 alcoholic liver disease patients, the prevalence of the genotypes was 83%, 17% and 0%. These results confirmed the previous observation that the incidence of ALDH2 deficiency is much lower in alcoholic liver disease patients than in the general population, and suggested that most of the ALDH2 deficient patients with alcoholic liver disease are heterozygous for the normal and mutant ALDH2 genes.     

Genetic Repeat Polymorphism in the Regulating Region of CYP2E1: Frequency and Relationship With Enzymatic Activity in Alcoholics

BACKGROUND: Differences in the regulatory region of the CYP2E1 gene could be responsible for the interindividual variation in the cytochrome P-450 2E1 (CYP2E1) involved in ethanol oxidation. Recently, a polymorphic repeat sequence in the human gene was described between -2178 and -1945 base pairs. Its frequency seemed to vary among different ethnic populations, and it was suspected to be related to an increased inducibility to further ethanol intake. In the study reported here, the frequency of this polymorphism was investigated in a white French population. Its relationship with the previously described PstI/RsaI or DraI CYP2E1 polymorphisms, alcoholism, alcoholic liver disease, and inducibility of CYP2E1 by ethanol was examined. METHODS: The polymorphic region was characterized by polymerase chain reaction in 103 controls, 148 alcoholic subjects without liver diseases, and 98 others with liver cirrhosis. By using in vivo chlorzoxazone (CHZ) metabolism, CYP2E1 phenotype was assessed in 36 non-ethanol-induced subjects (17 controls and 19 withdrawn alcoholics) and in 14 ethanol-induced subjects (10 controls after ingestion of 0.8 g/kg ethanol and four alcoholics with 100 g of daily intake). This phenotype was expressed as the 6-hydroxy CHZ/CHZ ratio. RESULTS: The rare allele frequency was found to be 1.58% in whites (n = 349). Neither significant association with alcoholism or alcoholic liver diseases, nor relationship with the PstI/RsaI polymorphism, was observed. But the DraI polymorphism was more frequent among the heterozygous subjects when compared with wild-type homozygous ones (p < 0.05). The CYP2E1 phenotype was similar in wild-type homozygotes and in heterozygotes at the constitutive level, as well as after induction with ethanol. CONCLUSIONS: Our data suggest that CYP2E1 repeat polymorphism does not seem to constitute a major factor for interindividual differences in CYP2E1 expression and susceptibility to alcohol-related disorders in whites.