• Korean Journal of Biological Psychiatry
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• v.12 no.2
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• pp.196-206
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• 2005

Objectives:The purpose of this study is to evaluate the pathophysiology of alcoholics by investigating the differences in frequency of Aldehyde Dehydrogenase 2(ALDH2) genotypes and ALDH2 alleles between patients with alcohol dependence and controls, and the differences of drinking and personality traits in Korean male alcoholics with ALDH2 genotype variances. Methods:The authors selected 98 patients with alcohol dependence and 53 controls. Self-report questionnaires for acute reponses after alcohol ingestion, the AUI(Alcohol Use Inventory), and the NEO-PI-R(NEO Personality Inventory Revised) were given to all patients with alcohol dependence. ALDH2 genotypes were typed with MboII RFLP(Restriction Fragment Length Polymorphism) method in 53 controls and 98 patients with alcohol dependence. The authors divided alcoholic patients into two groups according to the presence of variant $ALDH2^2$ allele;normal ALDH2 alcoholics(N=87) and variant ALDH2 alcoholics(N=11). Results:1) The genotypic frequencies of subjects with $ALDH2^{1/1}$ were higher and those with $ALDH2^{1/2}$ and $ALDH2^{2/2}$ were lower in patients than in controls. 2) Alcohol dependence could be found in $ALDH2^{2/2}$ homozygote individuals. 3) Variant ALDH2 alcoholics had more family problems in the AUI than normal ALDH2 alcoholics. 4) Variant ALDH2 alcoholics experienced more flushing and cardiovascular responses after alcohol ingestion than normal ALDH2 alcoholics. 5) Variant ALDH2 alcoholics had less altruistic personality traits in the NEO-PI-R than normal ALDH2 alcoholics. 6) Variant ALDH2 alcoholics tended to have more tolerance to alcohol than normal ALDH2 alcoholics. Conclusion:Variant $ALDH2^2$ allele might play a protective role in the pathogenesis of alcohol dependence and there were several significant differences of drinking and personality traits in Korean male alcoholics with ALDH2 genotype variances.

• The Korean Journal of Food And Nutrition
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• v.10 no.2
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• pp.268-271
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• 1997

Human mitochondrial aldehyde dehydrogenase(ALDH2) is mainly responsible for the oxidation of acetaldehyde generated during alcohol oxidation in vivo. To investigate the role of ALDH2 in alcohol metabolism, it was needed to get solubilized enzyme. The cDNA of ALDH2 is isolated from cDNA library and ligated to several expression vectors for E. coli. At almost expression system to be constructed, the broad expression band of ALDH2 was detected. But, the large part of the expressed protein consisted as inclusion body, the yield of solubilized enzyme was not more tan 5% of the total expressed amount. Recombinant ALDH2 was verified from the several expression systems.

• International Journal of Oral Biology
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• v.31 no.3
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• pp.107-112
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• 2006

Aldehyde dehydrogenase (ALDH) plays an important role in alcohol metabolism; ALDH is responsible for the oxidation of acetaldehyde generated during alcohol oxidation. ALDH is also known to oxidize various other endogenous and exogenous aldehydes. Cytochrome P-450 2E1 (CYP2E1), a liver microsomal enzyme, also metabolizes acetaldehyde and ethanol and can be induced by other inducers including acetone and ethanol. We examined single nucleotide polymorphisms (SNP) of ALDH and CYP2E1 genotypes in Korean. Restriction fragment length polymorphism (RFLP) method was used to determine ALDH and CYP2E1 SNP. Mutation in ALDH was 60% (heterozygote 46.7% and homozygote 13.3%) among 15 cases. CYP2E1 mutation was 52.7% (heterozygote 47.4% and homozygote 5.3%) among 19 cases.

• Biomedical Science Letters
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• v.14 no.1
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• pp.13-18
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• 2008

Excessive alcohol consumption is associated with increased risks of many diseases including cancer. Individuals who regularly consume excessive quantities of alcohol have a greater risk of developing head and neck cancers such as esophageal, pharyngeal and oral cavity cancers if they are deficient in ALDH2 expression compared to normal populations. We evaluated lipid peroxidation in Aldh2 +/+ and Aldh2 -/- mice after they had been subjected to acute ethanol exposure. Malondialdehyde(MDA) level in liver tissue was evaluated as a biomarker of oxidative lipid peroxidation. Although the ethanol treatment did not increase the hepatic MDA level both in Aldh2 +/+ mice and in Aldh2 -/- mice, the MDA level was significant higher in the Aldh2 -/- mice than in the Aldh2 +/+ group. The MDA level was also significantly correlated with olive tail moment in blood and the level of 8-OHdG in liver tissue. This is a strong evidence to support our hypothesis that oxidative stress is more intense in Aldh2 -/- mice than in Aldh2 +/+ mice. Our results suggest that ALDH2-deficient individuals may be more susceptible than wild-type ALDH2 individuals to ethanol-mediated liver disease, including cancer.

• Journal of Microbiology
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• v.37 no.1
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• pp.41-44
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• 1999

Human mitochondrial aldehyde dehydrogenase 2 (ALDH2) is mainly responsible for oxidation of acetaldehyde generated during alcohol oxidation in vivo. A full-length cDNA of human liver ALDH2 was successfully expressed using a vaccinia virus-T7 RNA polymerase system. The expressed ALDH2 had an enzymatic activity as high as the native human liver ALDH2 enzyme.

• Journal of Life Science
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• v.18 no.8
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• pp.1173-1176
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• 2008

Individuals who regularly consume excessive quantities of alcohol are at a greater risk of developing various cancers such as esophageal, pharyngeal and lung cancers compared to normal populations if they are deficient in ALDH2 enzyme activity. We evaluated oxidative DNA damage in the liver, brain, and lung tissues of Aldh2 +/+ and Aldh2 -/- mice after they had been subjected to acute ethanol exposure. The 8-hydroxydeoxyguanosine (8-OHdG) level in each tissue was evaluated as a biomarker of oxidative DNA damage. The 8-OHdG level in the liver, brain, and lung tissues was significantly increased following ethanol treatment. In addition, the level of 8-OHdG in the liver and lung tissues was affected by ALDH2 enzyme activity. This result suggests that ALDH2-deficient individuals may be more susceptible than wild-type ALDH2 individuals to ethanol-mediated diseases, including cancer.

• Journal of Life Science
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• v.21 no.11
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• pp.1636-1640
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• 2011

Alzheimer's disease (AD) is a progressive neurodegenerative disease, resulting in the loss of cognitive function. Mitochondrial aldehyde dehydrogenase (ALDH2) has been proposed to be a risk factor for the development of AD, but there is still controversy about that. In this study, we demonstrated the role of ALDH2 enzyme activity on amyloid-beta (A${\beta}$) and nuclear factor kappa B (NF-${\kappa}B$) expression in mice brain following ethanol exposure for 8 weeks. Five male Aldh2 (+/+) and Aldh2 (-/-) mice, 8 weeks-old of age (C57BL/6J strain), in each group were exposed to ethanol for 8 weeks (2 g/kg wt./day) using gavage. Those in the control groups received 0.9% saline alone. Results showed a difference in expression level of A${\beta}$ in the hippocampus after ethanol exposure according to the ALDH2 enzyme activity (p<0.05), but not in the level of NF-${\kappa}B$). Our results suggest a possibility that ALDH2 enzyme activity may be an important role in the development of AD.

• Journal of Life Science
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• v.21 no.8
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• pp.1163-1167
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• 2011

Excessive alcohol consumption causes various degenerative brain diseases including Alzheimer's disease and Parkinson's disease. Absorbed ethanol is metabolized to acetaldehyde and acetic acid by alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). Acetaldehyde is well known as a toxicant through generation of reactive oxygen species (ROS). Therefore, ALDH2 activity may play important roles in the pathogenesis of alcohol-induced brain diseases. In this study, we demonstrated the effects of ALDH2 enzyme activity on lipid peroxidation in brain tissues and urine of mice exposed to ethanol for 8 weeks. Five male, 8-week old Aldh2 (+/+) and Aldh2 (-/-) mice (C57BL/6J strain) in each group were exposed to ethanol for 8 weeks (2 g/kg wt./day) using gavage, and those in the control group received 0.9% saline alone. Thiobarbituric acid reactive substances (TBARS) level, a marker for lipid peroxidation, was measured in whole brain tissue and urine by high performance liquid chromatography. As a result, chronic ethanol treatment did not show any statistical change on the TBARS level of brain tissue in both Aldh2 (+/+) mice and in Aldh2 (-/-) mice. However, following ethanol exposure for 8 weeks in Aldh2 (-/-) mice, the urinary TBARS levels were significantly increased to more than double compared to the pretreatment group. This result was not observed in Aldh2 (+/+) mice. These results suggest that although ALDH2 enzyme activity plays a role in the generation of ROS in the whole body, it does not seem to be important in the pathogenesis of alcohol induced degenerative brain diseases.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.2
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• pp.591-594
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• 2015

Background: Aberrations in gene methylation patterns play important roles in gliomagenesis. However, whether the ALDH1A3 promoter methylation is related to prognoses of primary glioblastomas (GBMs) in Western China remains unclear. Materials and Methods: Methylation levels of ALDH1A3 CpG island in 36 GBMs were identified by pyrophosphate sequencing, while ALDH1A3 expression was assessed with matched paraffin section immunohistochemistry. Survival curves were analysed by Kaplan-Meier. Results: The hypermethylation status of ALDH1A3 promoter predicted a better prognosis accompanied with low expression of ALDH1A3 protein. Conclusions: Our results indicate ALDH1A3 promoter methylation correlates with prognosis in primary GBMs.

• Korean Journal of Biological Psychiatry
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• v.17 no.1
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• pp.26-36
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• 2010

Objectives : It is well-known that Korean people show distinctive drinking behaviors depending on the gene polymorphisms of alcohol metabolizing enzymes. This study examined the gene polymorphisms of ALDH2 and ADH1B and their combination on the drinking behaviors of Korean young adults. Methods : Through a follow-up survey performed for a cohort consisting of 551 university freshmen for six years, the authors attempted to identify genetic factors affecting drinking behaviors. In 2000, drinking behaviors and scores of CAGE questionnaires were assessed and ALDH2 gene polymorphism was determined with PCR-RFLP. In 2006(n= 150), AUDIT-K was assessed in addition to the above and gene polymorphism of ADH1B was determined through SNaPshot$^{TM}$ method. Results : While ALDH2*2 allele was associated with increased degree of drinking in 2000 and 2006. When both enzymes were active, the possibility to be classified into the risk group for alcohol dependence such as AUDIT-K(>12), and CAGE(>2) was high. Conclusion : The ALDH2 genotype had a significant effect on drinking behavior and degree of drinking during early adulthood. However, the combination of the active form of ADH1B and the active form of ALDH2 can be risk factor for problem drinking.