Alcohol Dehydrogenase Genotypes Research Articles

2556. A Phase 1, Open-Label, Single Dose Study to Evaluate the Pharmacokinetics (PK), Safety, and Tolerability of Epetraborole Tablets and the Impact of Alcohol Dehydrogenase (ADH) Genotype on the PK of Epetraborole and Metabolite M3 in Healthy Japanese Adult Subjects

Abstract Background Epetraborole (EBO), an orally available bacterial leucyl transfer RNA synthetase inhibitor with potent activity against nontuberculous mycobacteria, is under clinical development for treatment-refractory MAC lung disease. Nonclinical studies suggest that metabolism of EBO to metabolite M3 may involve oxidation by ADH. The goal of this study was to evaluate the impact of ADH genotype on the PK of EBO and M3 in healthy Japanese subjects. Methods In this open-label trial, a single 500 mg EBO dose was administered to subjects in 3 cohorts defined by ADH1B genotype (*1/*1, *1/*2, or *2/*2). EBO and M3 plasma concentrations were measured by a validated LC-MS/MS method, and plasma EBO and M3 PK were determined using non-compartmental methods. Standard clinical and laboratory evaluations and treatment-emergent adverse events (TEAEs) were assessed. Results 18 subjects were enrolled (6/cohort). EBO was rapidly absorbed, with M3 subsequently appearing in plasma. After reaching Cmax, EBO and M3 concentrations declined with a geometric mean t1/2 of 10.7 to 11.4 h and 26.7 to 33.1 h, respectively. EBO exposures (Cmax and AUC) were similar between Cohort 1 and Cohort 2, while exposures were 1.2- to 1.4-fold higher in Cohort 3 (Table); however, exposure of M3 was similar across all cohorts. Compared to Cohort 1, M3:EBO ratios for Cohort 3 were generally similar for Cmax and were approximately 26% lower for AUC. No apparent differences in t1/2 were observed across cohorts for either EBO or M3. No TEAEs or clinically significant changes in clinical laboratory parameters, vital signs, physical examinations, or ECGs were reported in this study. Conclusion Administration of EBO in Japanese subjects with varying ADH1B genotypes had no meaningful effect on EBO or M3 plasma exposure. The slightly increased EBO exposures associated with the 500 mg dosage in subjects with ADH1B *2/*2 genotype were within the range of tolerable exposures. Oral EBO was well tolerated in this study; no TEAEs were reported. This Phase 1 study did not identify any risk that would preclude evaluation of oral EBO administered 500 mg daily in patients with different ADH1B genotypes, including Japanese patients. Disclosures All Authors: No reported disclosures

Development of squamous neoplasia in esophageal iodine‐unstained lesions and the alcohol and aldehyde dehydrogenase genotypes of Japanese alcoholic men

We investigated the development of esophageal neoplasia in biopsy specimens of the distinct iodine-unstained lesions (DIULs) ≥ 5 mm detected in 280 of 2,115 Japanese alcoholic men who underwent screening by esophageal iodine staining. Low-grade intraepithelial neoplasia (LGIN) was diagnosed in 155 of them, high-grade intraepithelial neoplasia (HGIN) in 57, and invasive SCC in 35. The size of the DIULs increased with the degree of neoplasia. Most LGINs were flat and were missed before iodine staining. Some DIULs became a light pink color (PC) about 2 min after staining, and 2.6, 56.1 and 96.0% of the LGIN, HGIN and invasive SCC lesions, respectively, were PC-sign-positive. Multiple DIULs of any size markedly increased the risk of LGIN [adjusted OR (95%CI) = 10.1 (7.12-14.5)], HGIN [27.9 (14.6-53.4)] and invasive SCC [21.6 (10.1-46.4)], and were strongly associated with the presence vs. absence of DIULs ≥ 5 mm [13.3 (9.21-19.1)], inactive heterozygous aldehyde dehydrogenase-2 (ALDH2*1/*2) vs. ALDH2*1/*1 [2.60 (1.79-3.78)], and less-active alcohol dehydrogenase-1B (ADH1B*1/*1) vs. ADH1B*2 allele [2.61 (1.87-3.64)]. The combination of ALDH2*1/*2 and ADH1B*1/*1 synergistically increased the risk of LGIN [4.53 (2.17-9.47)], HGIN [10.4 (4.34-24.7)] and invasive SCC [21.7 (7.96-59.3)]. Esophageal neoplasia developed at earlier ages in those with ALDH2*1/*2. Biopsy-proven HGIN was diagnosed as invasive SCC in 15 (39.5%) of 38 patients after endoscopic mucosectomy or surgery. In conclusion, large size, non-flat appearance, positive PC sign and multiplicity of DIULs and ALDH2*1/*2 and ADH1B*1/*1 were associated with development of esophageal neoplasia in Japanese alcoholics. Biopsy-proven HGIN should be totally resected for both diagnostic and therapeutic purposes.

Alcohol drinking habits, alcohol dehydrogenase genotypes and risk of acute coronary syndrome

The risk of myocardial infarction is lower among light-to-moderate drinkers compared with abstainers. Results from some previous studies, but not all, suggest that this association is modified by variations in genes coding for alcohol dehydrogenase (ADH). We aimed to test this hypothesis, including alcohol as both the amount of alcohol and the frequency of drinking. we conducted a nested case-cohort study within the Danish Diet, Cancer and Health study, including 1,645 men (770 incident cases of acute coronary syndrome from 1993-1997 through 2004 and 875 randomly selected controls). Higher alcohol intake (measured as amount or drinking frequency) was associated with lower risk of acute coronary syndrome; however, there was no evidence that these finding were modified by ADH1B or ADH1C genotypes. The importance of functional variation in alcohol dehydrogenase for the association between alcohol drinking habits and the risk of developing acute coronary syndrome, if any, is very limited.

Alcohol Intake, Alcohol Dehydrogenase Genotypes and Liver Damage and Disease in the Danish General Population

We tested the hypothesis that alcohol, alone and in combination with alcohol dehydrogenase (ADH) 1B and ADH1C genotypes, affects liver damage and disease in the general population. Information on alcohol intake and on liver disease was obtained from 9,080 men and women from the Copenhagen City Heart Study. Biochemical tests for the detection of liver damage were specific for alanine aminotransferase (ALT), aspartate aminotransferase (AST)-to-ALT ratio (AST/ALT), gamma-glutamyl transpeptidase (gamma-GT), albumin, bilirubin, alkaline phosphatase, coagulation factors, and erythrocyte volume. Increasing alcohol intake was associated with increasing erythrocyte volume, AST/ALT, and levels of ALT, gamma-GT, albumin, bilirubin, coagulation factors, and with decreasing levels of alkaline phosphatase. Multifactorially adjusted hazard ratios for alcoholic liver disease overall were 0.9 (95% confidence interval (CI), 0.6-1.4), 1.4 (0.8-2.5), 1.8 (0.9-3.5), and 4.1 (2.5-7.0) for an alcohol intake of 1-13, 14-20, 21-27, and > or = 28 drinks per week, respectively, compared with drinking <1 drink per week (P for trend<0.0001); the corresponding hazard ratios for alcoholic liver cirrhosis were 1.7 (0.6-4.7), 2.0 (0.8-7.1), 6.5 (2.0-21), and 13 (4.6-37) (P for trend<0.0001). ADH1B and ADH1C genotypes were not associated with and did not modify the effect of alcohol on biochemical tests or risk of liver disease. Increasing alcohol intake from none to low (1-6 drinks per week) through to moderate (7-20 drinks per week) and excessive intake (> or = 21 drinks per week) leads to stepwise increases in signs of liver damage with no threshold effect, and to an increased risk of liver disease. The minor changes in biochemical tests for low alcohol intake may not account for subclinical liver disease.

Genetic polymorphisms of alcohol dehydrogenase-2 and aldehyde dehydrogenase-2 associated with the susceptibility on esophageal cancer

To evaluate the impact of alcohol dehydrogenase-2 (ADH2) and aldehyde dehydrogenase-2 (ALDH2) polymorphisms on the susceptibility of esophageal cancer. A case-control study including 221 cases of esophageal cancer and 191 controls was carried out in Taixing city of Jiangsu province. ADH2 and ALDH2 genotypes were tested by PCR and denaturing high performance liquid chromatography (DHPLC). (1) Compared with ALDH2 G/G carriers, ALDH2 A/A (OR = 5.69, 95% CI: 2.51-12.18) and ALDH2 G/A (OR = 1.70, 95% CI: 1.08-2.68) carriers showed a significantly elevated risk of developing esophageal cancer, especially among alcohol drinkers with ALDH2 A/A (OR = 8.63, 95% CI: 2.07-35.95). (2) Statistical relation was not found between ADH2 genotypes and the risk of esophageal cancer, with regard to the status of alcohol consumption. (3) Whether subjects with whatever ADH2 genotype, ALDH2 G/A or A/A carriers was found to have significantly increased the risk of developing esophageal cancer, with ALDH2 A/A carriers appeared having higher esophageal cancer risk than those ALDH2 G/A carriers. (4)Compared those non-drinkers with both ALDH2 G/G and ADH2 A/A, drinkers with ALDH2 G/A or A/A and ADH2 G/A or G/G genotypes showed a significantly elevated risk of developing esophageal cancer (OR = 8.36, 95% CI: 2.98-23.46). These results revealed that it was not ADH2 but ALDH2 polymorphisms and drinking alcohol had a significant interaction with the development of esophageal cancer, suggesting that in order to help lowering the risk of esophageal cancer, individuals who are carrying ALDH2 A/A or G/A genotypes should be encouraged to reduce their consumption of alcohols.

Polymorphisms of alcohol dehydrogenase-2 and aldehyde dehydrogenase-2 and esophageal cancer risk in Southeast Chinese males

To evaluate the impact of alcohol dehydrogenase-2 (ADH2) and aldehyde dehydrogenase-2 (ALDH2) polymorphisms on esophageal cancer susceptibility in Southeast Chinese males. Two hundred and twenty-one esophageal cancer patients and 191 healthy controls from Taixing city in Jiangsu Province were enrolled in this study. ADH2 and ALDH2 genotypes were examined by polymerase chain reaction and denaturing high-performance liquid chromatography. Unconditional logistic regression was used to calculate the odds ratios (OR) and 95% confidence interval (CI). The ADH G allele carriers were more susceptible to esophageal cancer, but no association was found between ADH2 genotypes and risk of esophageal cancer when disregarding alcohol drinking status. Regardless of ADH2 genotype, ALDH2G/A or A/A carriers had significantly increased risk of developing esophageal cancer, with homozygous individuals showing higher esophageal cancer risk than those who were heterozygous. A significant interaction between ALDH2 and drinking was detected regarding esophageal cancer risk; the OR was 3.05 (95% CI: 1.49-6.25). Compared with non-drinkers carrying both ALDH2 G/G and ADH2 A/A, drinkers carrying both ALDH2 A allele and ADH2 G allele showed a significantly higher risk of developing esophageal cancer (OR = 8.36, 95% CI: 2.98-23.46). Both ADH2 G allele and ALDH2 A allele significantly increase the risk of esophageal cancer development in Southeast Chinese males. ALDH2 A allele significantly increases the risk of esophageal cancer development especially in alcohol drinkers. Alcohol drinkers carrying both ADH2 G allele and ALDH2 A allele have a higher risk of developing esophageal cancer.

Alterations in Ethyl Alcohol Pharmacokinetics During Oral Consumption of Malt Liquor Beverages in African Americans

Malt liquor (ML) beverages have become increasingly popular among urban minority groups, due partly to their inexpensive price and targeted advertising. We hypothesized that nonfermented by-products contained in ML beverages will alter the pharmacokinetics (PK) and pharmacodynamic (PD) effects of its ethanol content. In addition, we determined the effect of alcohol dehydrogenase (ADH) genotypes on the PK following consumption of ML beverages. The study was conducted in 31 healthy adult African-American social drinkers, mean +/- SD age of 22.3 +/- 1.3 years, and weight of 70.7 +/- 10.9 kg. Participants were administered ethanol, in randomized order, 2-weeks apart, in the form of oral ML beverage (6%v/v), or isocaloric solution of diet soda-ethanol (DS-Etoh) beverage (6%v/v). During each session the beverage was consumed over 4 minutes and breath alcohol concentrations (BrAC) as well as subjective and behavioral effects of ethanol were evaluated over 180 minutes. Pharmacokinetic parameters of ethanol were calculated using Michaelis-Menten elimination kinetics. The effect of ML and ADH genotype on PK was evaluated using the Wilcoxon rank-sum test and the Wilcoxon signed rank test, respectively. Results show a slower mean rate of absorption, K(a), (0.12 vs. 0.15 min(-1), p = 0.03) and a longer time to reach maximum concentration, T(max), (28 vs. 23 minute, p < 0.01) for the ML compared with DS-Etoh beverage. The ML beverage resulted in a larger area under the BrAC-time curve compared with DS-Etoh beverage (8.4 vs. 6.8 min g/dl, p = 0.02). There was no difference in the subjective PD effects between the 2 beverages. Results show that exposure to ethanol following the consumption of ML beverages is different compared to that following nonmalt beverages in African-Americans. These differences may be related to nonfermented by-products present in commercially available ML products. These PK differences do not appear to result in significant perceived alcohol PD changes, nor are they related to ADH genotype.

P.6.b.005 Methylation of the dopamine transporter (DAT) gene is associated with craving in alcohol dependent patients

Variants in alcohol dehydrogenase (ADH) genes differ between ethnic groups and have, in some studies, been found to be associated with alcohol dependence and alcoholic liver disease. This study sought to determine whether an association exists between ADH (ADH1C previously ADH3, ADH1B*2 previously ADH2*2) genotypes, alcohol dependence, drinking history, and liver function tests in the two major ethnic groups of Trinidad and Tobago (TT). One hundred and forty-five alcohol-dependent individuals of both East Indian (Indo-TT) and African (Afro-TT) ancestry, and 108 controls matched by age, sex, and education participated in the study. Serum levels of alanine and aspartate aminotransferase (ALT, AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and gamma-glutamyltransferase (GGT) as well as presence of HIV, hepatitis B surface antigen, and anti-hepatitis C virus antibody were determined. There was a significant difference in the distribution of ADH1C allele polymorphisms between the ethnic groups (P < .0001). Forty-three percent of the Indo-TT were found to have one ADH1C*2 allele and 5% were homozygous, whereas, only 23% of Afro-TT had one allele and one was homozygous. Only three individuals had an ADH1B*2 allele (one Indo-TT alcohol dependent, two Indo-TT controls). The ADH1C*2 allele was significantly associated with alcohol dependence overall and within Indo-TT ancestry, however, it was not associated with current or heaviest alcohol consumption levels. Individuals with at least one ADH1C*2 allele also had significantly elevated levels of ALP (P < .02) and GGT (P < .02) as compared to individuals homozygous for ADH1C*. Additionally, GGT levels were also found to be elevated (P < .02) within Indo-TT alcohol dependents with at least one ADH1C*2 allele but not within the Afro-TT alcohol dependents with that allele. A linear regression that included alcohol dependence and levels of alcohol consumption confirmed that levels of serum GGT were significantly associated with the ADH1C*2 genotype. These results suggest that ADH1C polymorphisms are associated with alcohol dependence and alcohol associated elevations of liver enzymes in a population with a low frequency of ADH1B2 alleles.

P.6.b.006 Alcohol dependence: the chemical traumatic brain injury

Variants in alcohol dehydrogenase (ADH) genes differ between ethnic groups and have, in some studies, been found to be associated with alcohol dependence and alcoholic liver disease. This study sought to determine whether an association exists between ADH (ADH1C previously ADH3, ADH1B*2 previously ADH2*2) genotypes, alcohol dependence, drinking history, and liver function tests in the two major ethnic groups of Trinidad and Tobago (TT). One hundred and forty-five alcohol-dependent individuals of both East Indian (Indo-TT) and African (Afro-TT) ancestry, and 108 controls matched by age, sex, and education participated in the study. Serum levels of alanine and aspartate aminotransferase (ALT, AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and gamma-glutamyltransferase (GGT) as well as presence of HIV, hepatitis B surface antigen, and anti-hepatitis C virus antibody were determined. There was a significant difference in the distribution of ADH1C allele polymorphisms between the ethnic groups (P < .0001). Forty-three percent of the Indo-TT were found to have one ADH1C*2 allele and 5% were homozygous, whereas, only 23% of Afro-TT had one allele and one was homozygous. Only three individuals had an ADH1B*2 allele (one Indo-TT alcohol dependent, two Indo-TT controls). The ADH1C*2 allele was significantly associated with alcohol dependence overall and within Indo-TT ancestry, however, it was not associated with current or heaviest alcohol consumption levels. Individuals with at least one ADH1C*2 allele also had significantly elevated levels of ALP (P < .02) and GGT (P < .02) as compared to individuals homozygous for ADH1C*. Additionally, GGT levels were also found to be elevated (P < .02) within Indo-TT alcohol dependents with at least one ADH1C*2 allele but not within the Afro-TT alcohol dependents with that allele. A linear regression that included alcohol dependence and levels of alcohol consumption confirmed that levels of serum GGT were significantly associated with the ADH1C*2 genotype. These results suggest that ADH1C polymorphisms are associated with alcohol dependence and alcohol associated elevations of liver enzymes in a population with a low frequency of ADH1B2 alleles.

Genetic polymorphisms ofADH2andALDH2association with esophageal cancer risk in southwest China

To evaluate the impact of alcohol dehydrogenase 2 (ADH2) and aldehyde dehydrogenase 2 (ALDH2) polymorphisms on esophageal cancer risk. One hundred and ninety-one esophageal cancer patients and 198 healthy controls from Yanting County were enrolled in this study. ADH2 and ALDH2 genotypes were examined by polymerase-chain-reaction with the confronting-two-pair-primer (PCR-CTPP) method. Unconditional logistic regression was used to calculate the odds ratios (OR) and 95% confidence interval (95% CI). Both ADH2 1 allele and ALDH2 1/ 2 allele showed an increased risk of developing esophageal cancer. The adjusted OR (95% CI) for ADH2 1 allele compared with ADH2 2/ 2 was 1.65 (95% CI = 1.02-2.68) and 1.67 (95% CI = 1.02-2.72) for ALDH2 1/ 2 compared with ALDH2 1/ 1. A significant interaction between ALDH2 and drinking was detected regarding esophageal cancer risk, the OR was 1.83 (95% CI = 1.13-2.95). Furthermore, when compared with ADH2 2/ 2 and ALDH2 1/ 1 carriers, ADH2 1 and ALDH2 2 carriers showed an elevated risk of developing esophageal cancer among non-alcohol drinkers (OR = 2.46, 95% CI = 0.98-6.14), and a significantly elevated risk of developing esophageal cancer among alcohol drinkers among alcohol drinkers (OR = 9.86, 95% CI = 3.10-31.38). ADH2 and ALDH2 genotypes are associated with esophageal cancer risk. ADH2 1 allele and ALDH2 2 allele carriers have a much higher risk of developing esophageal cancer, especially among alcohol drinkers.

ADH1C*2 allele is associated with alcohol dependence and elevated liver enzymes in Trinidad and Tobago

Variants in alcohol dehydrogenase (ADH) genes differ between ethnic groups and have, in some studies, been found to be associated with alcohol dependence and alcoholic liver disease. This study sought to determine whether an association exists between ADH ( ADH1C previously ADH3, ADH1B*2 previously ADH2*2) genotypes, alcohol dependence, drinking history, and liver function tests in the two major ethnic groups of Trinidad and Tobago (TT). One hundred and forty-five alcohol-dependent individuals of both East Indian (Indo-TT) and African (Afro-TT) ancestry, and 108 controls matched by age, sex, and education participated in the study. Serum levels of alanine and aspartate aminotransferase (ALT, AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and gamma-glutamyltransferase (GGT) as well as presence of HIV, hepatitis B surface antigen, and anti-hepatitis C virus antibody were determined. There was a significant difference in the distribution of ADH1C allele polymorphisms between the ethnic groups ( P < .0001). Forty-three percent of the Indo-TT were found to have one ADH1C*2 allele and 5% were homozygous, whereas, only 23% of Afro-TT had one allele and one was homozygous. Only three individuals had an ADH1B*2 allele (one Indo-TT alcohol dependent, two Indo-TT controls). The ADH1C*2 allele was significantly associated with alcohol dependence overall and within Indo-TT ancestry, however, it was not associated with current or heaviest alcohol consumption levels. Individuals with at least one ADH1C*2 allele also had significantly elevated levels of ALP ( P < .02) and GGT ( P < .02) as compared to individuals homozygous for ADH1C*. Additionally, GGT levels were also found to be elevated ( P < .02) within Indo-TT alcohol dependents with at least one ADH1C*2 allele but not within the Afro-TT alcohol dependents with that allele. A linear regression that included alcohol dependence and levels of alcohol consumption confirmed that levels of serum GGT were significantly associated with the ADH1C*2 genotype. These results suggest that ADH1C polymorphisms are associated with alcohol dependence and alcohol associated elevations of liver enzymes in a population with a low frequency of ADH1B2 alleles.

Alcohol Dehydrogenase 2 His47Arg Polymorphism Influences Drinking Habit Independently of Aldehyde Dehydrogenase 2 Glu487Lys Polymorphism: Analysis of 2,299 Japanese Subjects

Although the functional effect of alcohol dehydrogenase 2 (ADH2) His(47)Arg polymorphism has been elucidated, its effect on habitual drinking remains unknown. Here, we conducted a cross-sectional study in 2,299 nonalcoholic Japanese subjects (989 men and 1,310 women). Drinking status, ethanol consumption, and physical reaction to one glass of beer were examined with regard to ADH2 and aldehyde dehydrogenase 2 (ALDH2) polymorphism. Strength of associations were assessed by age-, sex-, smoking status-, and genotype-adjusted odds ratios and their 95% confidence intervals. ADH2 His/Arg and Arg/Arg genotypes showed higher risk for habitual drinking. Among men, ALDH2 genotype- and confounder-adjusted odds ratios (95% confidence intervals) were 1.30 (0.89-1.89) and 3.16 (1.03-9.70), and this trend was significant (P = 0.024). A similar trend was observed among women. The combination genotypes of two polymorphisms revealed the clear effect of the ADH2 Arg allele among those with ALDH2 Glu/Lys in both sexes (P(trend) = 0.007 for men and 0.024 for women). Physical reactions, such as flushing and palpitation, were significantly less common in those with Arg/Arg compared with other ADH2 genotypes, and this was marked when combined with ALDH2 Glu/Lys. Heavy drinker status was also strongly associated with ADH2 Arg alleles. In conclusion, this study showed the strong effect of ADH2 His(47)Arg polymorphism on habitual drinking regardless of ALDH2 genotype.

ADH3 genotype, alcohol intake and breast cancer risk

Moderate alcohol consumption of approximately 1-2 drinks per day has been associated with a 30-50% increase in breast cancer risk. Individuals differ in their ability to metabolize alcohol through genetic differences in alcohol dehydrogenase (ADH), the enzyme that catalyzes the oxidation of approximately 80% of ethanol to acetaldehyde, a known carcinogen. Individuals differ in their ADH genotype, and one locus in particular (ADH3) is polymorphic in Caucasian populations. Using data from the Long Island Breast Cancer Study Project, we examined whether fast metabolizers of alcohol, as measured by the ADH3(1-1) genotype, have a higher risk of breast cancer from alcohol intake compared with those individuals who are slow metabolizers, but consume similar amounts of alcohol. We combined genotyping information with questionnaire data on 1047 breast cancer cases and 1101 controls and used unconditional logistic regression methods to estimate multivariate-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) between alcohol intake and breast cancer risk. Among individuals homozygous for the fast metabolizing allele (ADH(3)1-1), a lifetime alcohol consumption of 15-30 g/day (approximately 1-2 drinks per day) increased breast cancer risk by 2-fold (OR=2.0, 95% CI=1.1-3.5). In contrast, the increase in risk from a lifetime alcohol consumption of 15-30 g/day was less pronounced in the intermediate and slow metabolizing groups, respectively: ADH3(1-2) (OR=1.5, 95% CI 0.9-2.4) and ADH(3)2-2 (OR=1.3, 95% CI 0.5-3.5). Fast metabolizers who drank 15-30 g/day of alcohol had 2.3 times (95% CI 1.3-4.0) greater risk of breast cancer than non-drinkers who were intermediate or slow metabolizers. This association for fast metabolizers who drank 15-30 g/day was particularly pronounced among premenopausal women (premenopausal women OR=2.9, 95 % CI=1.2-7.1; postmenopausal women OR=1.8, 95% CI=0.9-3.8). These population-based data support the hypothesis that fast metabolizers of alcohol have a higher risk of breast cancer risk, from alcohol intake than slow metabolizers.

Role of epoxide hydrolase, NAD(P)H:quinone oxidoreductase, cytochrome P450 2E1 or alcohol dehydrogenase genotypes in susceptibility to colorectal cancer

Colorectal cancer (CRC) is one of the most common forms of cancer in Western countries. CRC has been associated with genetic and lifestyle factors. Individual susceptibility to CRC may be due partly to variations in detoxification capacity in the gastrointestinal tract. Genetic polymorphisms in detoxification enzymes may result in variations in detoxification activities, which subsequently might influence the levels of toxic/carcinogenic compounds, and this may influence the risk for CRC. Therefore, we determined whether polymorphisms in the genes coding for microsomal epoxide hydrolase ( EPHX1), NAD(P)H:quinone oxidoreductase ( NQO1), cytochrome P450 2E1 ( CYP2E1) and alcohol dehydrogenase ( ADH3) predispose to the development of CRC. DNA samples were obtained from 371 patients with sporadic CRC and 415 healthy controls. Patients and controls were all of Caucasian origin. All genetic polymorphisms were determined by polymerase chain reaction, eventually followed by restriction-fragment-length-polymorphism analyses, except for the EPHX1 codon 113 polymorphism, which was genotyped by an allele-specific discrimination assay. Calculation of crude Odds Ratios (ORs) revealed an increased risk for CRC associated with variant NQO1 (OR 1.5, 95% CI 1.1–2.0) and CYP2E1 intron 6 genotypes (OR 2.2, 95% CI 1.3–3.8). However, after adjustment for age and gender, logistic regression analyses only showed a statistically significant risk for CRC associated with variant NQO1 genotypes (OR 1.6, 95% CI 1.03–2.4). No associations were found between CRC and the other polymorphic genes as mentioned above. In conclusion, these data suggest that the presence of variant NQO1 genotypes, with expected reduced enzyme activities might enhance susceptibility to CRC.

NEUROBIOLOGICAL ALTERATIONS IN THE HUMAN ALCOHOLIC BRAIN: EFFECT OF GENOTYPE.

Long-term alcohol abuse by human subjects leads to selective brain damage that is restricted in extent and variable in severity. Within the cerebral cortex, neuronal loss is most marked in the superior frontal cortex and relatively mild in motor cortex. Cirrhotic alcoholics and subjects with alcohol-related Wernicke-Korsakoff syndrome show more severe and more extensive damage than do uncomplicated cases. Accumulating evidence suggests that the likelihood of developing alcohol dependency is associated with one or more genetic markers. In previous work we showed that GABAA receptor functionality, and the subunit isoform expression that underlies this, differed in region- and disease-specific ways between alcoholics and controls. By contrast, glutamate receptor (NMDA, KA, AMPA) differences were muted or absent. Here we asked if genotype differentiated the form, pharmacology, or expression of glutamate and GABA receptors in pathologically vulnerable and spared cortical regions, with a view to determining whether such subject factors might influence the severity of alcohol-induced brain damage. Cerebrocortical tissue was obtained at autopsy under informed, written consent from uncomplicated and alcoholic-cirrhotic Caucasian (predominantly Anglo-Celtic) cases, together with matched controls and cases with cirrhosis of non-alcoholic origin. All subjects had pathological confirmation of liver and brain diagnosis; none had been polydrug abusers. Samples were processed for synaptic membrane receptor binding, mRNA analysis by quantitative RT-PCR, and protein analysis by Western blot. Genotyping was performed by PCR methods, in the main using published primers. Several genetic markers differentiated between our alcoholic and control subjects, including the GABAA receptor 2 subunit (GABB2) gene ( 2 (3) 10.329, P 0.01), the dopamine D2 receptor B1 (DRD2B) allele ( 2 (3) 10.109, P 0.01) and a subset of the alcohol dehydrogenase-3 (ADH3) alleles ( 2 (2) 4.730, P 0.05). Although neither the type-2 glutamate transporter (EAAT2) nor the serotonin transporter (5HTT) genes were significantly associated with alcoholism, only EAAT2 heterozygotes showed a significant association between ADH3 genotype and alcoholism ( 2 (3) 7.475, P 0.05). Other interactions between genotypes were also observed. DRD2A, DRD2B, GABB2, EAAT2 and 5HTT genotypes did not divide alcoholic cases and controls on NMDA receptor parameters, although in combined subjects there was a significant DRD2B X Area Interaction with glutamateNMDA receptor efficacy (F(1,57) 4.67; P 0.05), measured as the extent of glutamate-enhanced MK801 binding. In contrast, there was a significant Case-group X ADH3 X Area Interaction with glutamateNMDA receptor efficacy (F(3,57) 2.97; P 0.05). When GABAA receptor subunit isoform expression was examined, significant Case-group X Genotype X Area X Isoform interactions were found for EAAT2 with subunit mRNA (F(1,37) 4.22; P0.05), for GABB2 with isoform protein (F(1,37) 5.69; P 0.05), and for DRD2B with isoform protein (F(2,34)5.69; P0.05). The results suggest that subjects’ genetic makeup may modulate the effectiveness of amino acid-mediated transmission in different cortical regions, and thereby influence neuronal vulnerability to excitotoxicity.

Incorporation of the genetic control of alcohol dehydrogenase into a physiologically based pharmacokinetic model for ethanol in humans.

The assessment of the variability of human responses to foreign chemicals is an important step in characterizing the public health risks posed by nontherapeutic hazardous chemicals and the risk of encountering adverse reactions with drugs. Of the many sources of interindividual variability in chemical response identified to date, hereditary factors are some of the least understood. Physiologically based pharmacokinetic modeling linked with Monte Carlo sampling has been shown to be a useful tool for the quantification of interindividual variability in chemical disposition and/or response when applied to biological processes that displayed single genetic polymorphisms. The present study has extended this approach by modeling the complex hereditary control of alcohol dehydrogenase, which includes polygenic control and polymorphisms at two allelic sites, and by assessing the functional significance of this hereditary control on ethanol disposition. The physiologically based pharmacokinetic model for ethanol indicated that peak blood ethanol levels and time-to-peak blood ethanol levels were marginally affected by alcohol dehydrogenase genotypes, with simulated subjects possessing the B2 subunit having slightly lower peak blood ethanol levels and shorter times-to-peak blood levels compared to subjects without the B2 subunit. In contrast, the area under the curve (AUC) of the ethanol blood decay curve was very sensitive to alcohol dehydrogenase genotype, with AUCs from any genotype including the ADH1B2 allele considerably smaller than AUCs from any genotype without the ADH1B2 allele. Furthermore, the AUCs in the ADH1C1/C1 genotype were moderately lower than the AUCs from the corresponding ADH1C2/C2 genotype. Moreover, these simulations demonstrated that interindividual variability of ethanol disposition is affected by alcohol dehydrogenase and that the degree of this variability was a function of the ethanol dose.

Pooled Analysis of Alcohol Dehydrogenase Genotypes and Head and Neck Cancer: A HuGE Review

Possession of the fast metabolizing alleles for alcohol dehydrogenase (ADH), ADH1B*2 and ADH1C*1, and the null allele for aldehyde dehydrogenase (ALDH), ALDH2*2, results in increased acetylaldehyde levels and is hypothesized to increase the risk of head and neck cancer. To examine this association, the authors undertook a Human Genome Epidemiology review on these three genes and a pooled analysis of published studies on ADH1C. The majority of Asians had the fast ADH1B*2 and ADH1C*1 alleles, while the majority of Caucasians had the slow ADH1B*1/1 and ADH1C*1/2 genotypes. The ALDH2*2 null allele was frequently observed among Asians, though it was rarely observed in other populations. In a pooled analysis of data from seven case-control studies with a total of 1,325 cases and 1,760 controls, an increased risk of head and neck cancer was not observed for the ADH1C*1/2 genotype (odds ratio = 1.00, 95% confidence interval: 0.81, 1.23) or the ADH1C*1/1 genotype (odds ratio = 1.14, 95% confidence interval: 0.92, 1.41). Increased relative risks of head and neck cancer were reported for the ADH1B*1/1 and ALDH2*1/2 genotypes in several studies. Recommendations for future studies include larger sample sizes and incorporation of relevant ADH and ALDH genes simultaneously, as well as other genes. These considerations suggest the potential for the organization of a consortium of investigators conducting studies in this field.

Lung Cancer in Humans Is Not Associated with Lifetime Total Alcohol Consumption or with Genetic Variation in Alcohol Dehydrogenase 3 (ADH3)

Although there is clear evidence that smoking is the primary risk factor for lung cancer, not all variation in disease risk is understood. There is some evidence that alcohol may contribute to risk. We examined lifetime and recent (12-24 mo previous) alcohol consumption in relation to risk of lung cancer in a case-control study in western New York. In addition we examined the alcohol dehydrogenase 3 (ADH3) genotype in relation to lung cancer risk; ADH3 is rate limiting in alcohol metabolism and has a functional polymorphism. We interviewed incident, primary, histologically confirmed lung cancer cases (n = 111) in two counties. Controls were randomly selected from among those residing in the counties, frequency-matched to cases for age and race (n = 1546). Lifetime and recent total alcohol and beverage-specific alcohol consumption as well as relevant confounders were assessed by interview. ADH3 genotype was evaluated by a PCR-restriction fragment length polymorphism assay. Because of the small sample size, power was limited and CI were wide. Residual confounding by smoking remains a concern. Although we found a significant trend for increased risk for beer consumption in the recent period (odds ratio 1.67, 95% CI 0.96-2.92, P for trend = 0.05), chance cannot be ruled out as an explanation. We found no evidence of risk related to lifetime alcohol consumption nor evidence that alcohol dehydrogenase genotype modifies risk related to alcohol and lung cancer.

Do the ethanol metabolizing enzymes modify the relationship between alcohol consumption and blood pressure?

Several cross-sectional studies have examined whether the relationship between alcohol consumption and blood pressure (alcohol-BP relationship) differs among individuals with different aldehyde dehydrogenase-2 (ALDH2) genotypes, but few studies have examined the association with alcohol dehydrogenase-2 (ADH2), and those have yielded inconsistent results. We examined the potential modulatory effects of ADH2 and ALDH2 genotypes on the alcohol-BP relationship in a cross-sectional sample of a Japanese rural community. The study subjects were 335 randomly selected men aged 40-69 years, who lived in Shiso, a Japanese rural county, in 1999 or 2000. The genetic polymorphisms of ADH2 and ALDH2 were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. The frequencies of ADH21/21 (wild-type), 21/22 (superactive heterozygotes), and 22/22 (superactive homozygotes) were 8.4, 34.9 and 56.7%, respectively; and those of ALDH21/21 (wild-type), 21/22 (inactive heterozygotes), and 22/22 (inactive homozygotes) were 52.8, 40.9, and 6.3%, respectively. A multiple linear regression analysis showed that the relationship between alcohol consumption and diastolic blood pressure was significantly stronger in men with ADH21/21 than those with ADH21/22 or 22/22 (adjusted regression coefficient = 0.0392 versus 0.0113 mmHg for + 1 g ethanol/week, P for difference in slope = 0.018). The strength of the alcohol-BP relationship was similar in all of the ALDH2 genotype groups. The alcohol-BP relationship was significantly stronger in men with ADH21/21 than in men with ADH21/22 or 22/22 in this Japanese rural population. This finding was exactly the opposite of what one previous study suggested.

The ADH3*2 and CYP2E1 c2 alleles increase the risk of alcoholism in Mexican American men

To identify the association between the polymorphisms of genes encoding alcohol metabolizing enzymes and alcoholism, the alcohol dehydrogenase 2 (ADH2), alcohol dehydrogenase 3 (ADH3), aldehyde dehydrogenase 2 (ALDH2), and cytochrome P450 2E1 (CYP2E1) genes were studied in 101 male Mexican American alcoholics. One hundred and four Mexican American nonalcoholic males served as controls. The allele frequency of ADH2*2 (4.3%) and ALDH2*2 (0%), which are considered as protective alleles against alcohol drinking, is very low in Mexican Americans and no association is found between these alleles and alcohol dependence. A strong association was found between ADH3 genotype and alcoholism; the percentage of subjects who carry the ADH3*2 allele was significantly higher in alcoholics (64.4%) than controls (50%). Association was also found between the CYP2E1 RsaI c2 allele and alcohol dependence; the percentage of subjects who carry the RsaI c2 allele was significantly higher in alcoholics (34.7%) than in nonalcoholics (22.1%). The subjects whose alcohol drinking onset age is younger than 25 have much higher CYP2E1 c2 allele frequency than those whose alcohol drinking onset age is older than 25 (22.1% vs 15.7%). Among 101 alcoholics, only 18 subjects carry neither ADH3*2 nor CYP2E1 c2 alleles. For those subjects who have an ADH*1/*1 background, a strong association is found between CYP2E1 RsaI/ DraI genotype and alcoholism; the CYP2E1 RsaI c2 and DraI C allele frequencies are much higher in alcoholics than in nonalcoholics (26.4% vs 9.6% for c2 and 27.8% vs 13.5% for C allele). Taken together, ADH3*2 and CYP2E1 c2/C alleles might independently contribute to the development of alcoholism in Mexican American men.