Impact of ALDH2 Gene Polymorphism on Coronary Artery lesions in Ethnic Hakka Population with Acute Myocardial Infarction

Background: Aldehyde dehydrogenase 2 (ALDH2) contributes to converting acetaldehyde into acetate, thus plays a key role in the ethanol metabolism and oxidation of acetaldehyde. The aim of this study is to investigate the impact of Aldehyde dehydrogenase 2 (ALDH2) gene polymorphism on coronary artery lesions in ethnic Hakka patients with acute myocardial infarction (AMI). Methods: A total of 312 patients (male = 241, female = 71) with acute myocardial infarction (AMI) suffered ≥ 50% stenosis of at least one major coronary artery were recruited into the study. Lesions of AMI patients carried different ALDH2 genotypes were analyzed. Results: The incidence of multivessel lesions was higher in the ALDH2 mutation group (90.6%) than the ALDH2 wild group (80.3%) with reaching statistical signicance (p = 0.009). Compare to the single lesion group, multivessel lesions group were more likely to be lower DBP (77.3 ± 14.1 versus 86.4 ± 13.8, p = 0.004), older (66.1 ± 12.2 versus 59 ± 12.1, p = 0.009), have hypertension (55.7% versus 30.8%, p = 0.023) in the ALDH2 wild patients. In the ALDH2 mutation patients, multivessel lesions group also tend to be elderly (65.9 ± 11.3 versus 58.5 ± 11.3, p = 0.011). In the addition, the multivessel lesions group presented higher levels of the TG and lower levels of the LDL-C than the single lesion group, but it is no statistical differences. The logistics regression showed that age and ALDH2 mutation were vulnerable to the multivessel lesions the ethnic Hakka population with AMI. Conclusions: The AMI patients in ethnic Hakka population carrying mutated ALDH2 allele was vulnerable to multiple coronary artery lesions. ALDH2 allele was associated with multiple coronary artery lesions in AMI patients among ethnic Hakka population. Data are presented as mean ± SD. * p < 0.05, ** p < 0.01. SBP, systolic blood pressure; DBP, diastolic blood pressure; CREA, creatinine ; ALT, alanine transaminase; LM, left main disease; LAD, left anterior descending artery; LCX, left circumex; RCA, right coronary artery; TG, triglyceride; TC, total cholesterol; HDL-C, high density lipoprotein cholesterol; LDL-C, low density lipoprotein cholesterol. ALDH2: ; SBP: DBP: diastolic blood pressure; CREA: creatinine ; ALT: alanine transaminase; LM: left main disease; LAD: left anterior descending artery; LCX: left circumex; RCA: right coronary artery; TG: triglyceride; TC: total cholesterol; HDL-C: high density lipoprotein cholesterol; LDL-C: low density lipoprotein cholesterol.


Subjects
The study subjects were choosed from patients who attended the cardiology department of Meizhou People's Hospital and diagnosed with AMI during August 2016 and May 2019. A total of 312 patients with AMI suffered ≥ 50% stenosis of at least one major coronary artery were recruited into the study. All subjects were Hakka ethnic population residing in the Meizhou city. De nition of diseased vessel: left main disease and 3 subepicardial coronary artery, left anterior descending, left circum ex, right coronary stenosis ≥ 50% by coronary angiography were de ned as coronary lesions. Only one vessel involvement was de ned as a single vessel lesion, and more than single vessel lesion was identi ed as multivessel lesions. This study was performed according to the ethical guidelines of the Helsinki Declaration and approved by the Human Ethics Committees of the Meizhou People's Hospital (Huangtang Hospital), Meizhou Academy of Medical Sciences, Meizhou Hospital A liated to Sun Yat-sen University, Guangdong Province, China. All participants had signed the informed consent before the study.

DNA extraction and genotyping
Two milliliters of peripheral venous blood sample was collected in vacuum tubes containing EDTA.
Genomic DNA was extracted from the blood of subjects using the TIANamp Blood DNA Kit (Tiangen, Beijing, China) following the manufacturer's instructions, and DNA concentration was evaluated by using a Nanodrop 2000™ Spectrophotometer (Thermo Fisher Scienti c, Waltham, MA). Genotyping of ALDH2 and multivessel lesions was an independent risk factor for predicting death and reinfarction in patients [13].
Aldehyde dehydrogenase 2 (ALDH2) contributes to converting acetaldehyde into acetate, thus plays a key role in the ethanol metabolism and oxidation of acetaldehyde [14]. ALDH2 is also the key enzyme for nitroglycerin metabolism. Carriers of the ALDH2 * 2 genetype is involved in the transformation from nitroglycerin to nitric oxide that plays a crucial role in nitroglycerin tolerance in Asian patients with CAD [15]. The ALDH2 gene consisted of 13 exons on chromosome 12. There are three genotypes named wild type ( * 1/ * 1, homozygote), mutated type ( * 1/ * 2, heterozygote and * 2/ * 2, homozygote) and two ALDH2 alleles (ALDH2 * 1 and ALDH2 * 2) owing to a single nucleotide polymorphism (rs671) leads to the transition of guanine (G) to adenine (A), at last, an amino acid change at position 504 from glutamate to lysine in the ALDH2 protein [15][16][17]. The research showed that ALDH2 heterozygous individuals (ALDH2 * 1/ * 2) had only 6.25% of the enzymatic activity compared to the ALDH2 homozygous individuals (ALDH2 * 1/ * 1), while ALDH2 * 2/ * 2 basically eliminated its dehydrogenase activity [18]. The variant of ALDH2 gene Glu504Lys is frequent in East Asian population with a prevalence of 30-50% [15].
At present, the relationship of ALDH2 gene polymorphism and coronary artery lesions in AMI patients of ethnic Hakka population remains unclear. In this study, we aimed to investigate the impact of ALDH2 gene polymorphism on coronary artery lesions in AMI patients among Hakka population. Glu504Lys (rs671) polymorphisms was performed by polymerase chain reaction (PCR) ampli cation, and using a commercial detection kit (BaiO Technology Co, Ltd., Shanghai, China) was subjected to hybridization reaction. The 25 μL polymerase chain reaction mixture contained 20~120 ng DNA template and the recommended amounts of primers, Taq DNA polymerase and dNTPs. The PCR cycling conditions was performed according to the protocol: 50°C for 5 min, predenaturation at 94°C for 5 min, followed by 35 cycles at 94°C for 25 s, 60°C for 25 s and 72°C for 30 s, and nal extension at 72°C for 5min. The 10 μL amplifcation products were then dispensed into 190 μL of hybridization buffer to carry out the hybridization reaction. The genotypes of ALDH2 were visualized by using the BaiO Array Doctor Version 2.0 software (BaiO Technology Co, Ltd., Shanghai, China), according to the manufacturer's instructions.

Statistical analysis
Statistical Packagefor the Social Sciences (SPSS), version 21.0 was used for data analysis. The data are presented as the means ± SD. Chi-square test and Student's t-test were used to compare the wild and mutated genetype. Multivariate logistic regression analyses were used to determine the predictors of multivessel lesions in patients with different genotypes. A value of p < 0.05 was considered as statistically signi cant.

Discussion
In this study, we found that the ethnic Hakka population with AMI carrying mutated ALDH2 allele was associated with increased risk of multiple coronary artery lesions. There is a hypothesis that multiple coronary artery lesions and ALDH2 genotype is closely related to the ethnic Hakka population with AMI.
To con rmed the assumption, we analyzed the characteristics of the single lesion group and the multivessel lesions group in ALDH2 wild genotype group or mutated genotype group, respectively. The AMI with ALDH2 wild genotype patients with lower DBP were more likely to be older, have hypertension, elevated diseased vessels in multivessel lesions group. In addition, single lesion group had higher levels of the TG and lower levels of the LDL-C compare to the multivessel lesions group. The AMI with ALDH2 mutated genotype patients also tend to be elderly and increased diseased vessels in multivessel lesions group. The multivessel lesions group had higher levels of the TG and lower levels of the LDL-C than the single lesion group, but it is no statistical differences. The logistics regression showed that age and ALDH2 mutation were vulnerable to the multivessel lesions the ethnic Hakka population with AMI.
ALDH2 is a key enzyme involved in the detoxi cation of alcohol metabolite acetaldehyde. It is also involved in the oxidation of other aldehydes. It not only has dehydrogenase activity, but also has reductase and esterase activity [19]. The ALDH2 mutant enzyme activity was signi cantly reduced, and the ALDH2 mutant homozygote basically eliminated its dehydrogenase activity, and the heterozygote was only about 6% [20]. In recent years, it has been shown that ALDH2 may play a role in cardioprotection by oxidative detoxi cation of aldehydes, etc. Ebert et al. [21] con rmed that ALDH2 mutants increase ROS and toxic aldehydes in human pluripotent stem cell-derived cardiomyocytes, thereby inducing cells cyclic arrest and activation of apoptotic signaling pathways, especially during ischemic injury, reduce myocardial cell survival. When the ALDH2 gene is mutated, it will reduce the activity of ALDH2 and make ethanol in vivo. The procedure of alcohol consumption that ethanol → acetaldehyde → Water, carbon dioxide metabolism is blocked, a large amount of acetaldehyde will be stayed in the body, will increase the severity of healthy. People with mutation in the ALDH2 gene cannot quickly complete the alcohol metabolism process, resulting in the accumulation of acetaldehyde in the body will cause serious damage to the liver, kidney, heart and brain of the human body. In recent years, there have been more and more studies on ALDH2 Glu504Lys polymorphism and cardiovascular disease, especially coronary heart disease. Firstly, Japanese researcher Takagi et al found that the ALDH2 * 2 allele is an independent risk factor for myocardial infarction in the Japanese population after adjusting for traditional cardiovascular risk factors and alcohol consumption [22]. Subsequently, Hashimoto et al [23] also aimed at Japanese males, suggesting that people with ALDH2 mutations have a higher risk of coronary heart disease. Moreover, Chinese scholar Guo et al. [24] obtained similar conclusions to Takagi and Hashimoto that ALDH2 * 2 allele is an acute coronary syndrome (ACS) that is independent of traditional risk factors and drinking in the Han population or risk factors for coronary heart disease. More importantly, a Japanese genome-wide association study in 2012 found that ALDH2 Glu504Lys is a genetic susceptibility locus for coronary heart disease [25]. A growing number of evidence suggests that the ALDH2 gene mutation is one of the risk factors for coronary heart disease. Our study also showed that ALDH2 * 2 allele is an independent risk factor for myocardial infarction Hakka population with on coronary artery lesions Multivessel lesions was associated with lower diastolic blood pressure (DBP) in wild genotype patients with AMI (77.3 ± 14.1 versus 86.4 ± 13.8, p < 0.01) [26,27]. Our nding was in consisitent with previous analyses lower DBP is an increased risk for cardiovascular events and acute myocardial infarction. Other study has con rmed that ALDH2 wild genotype is a risk factor for hypertension in Asian population (OR = 1.31, 95% CI 1.18-1.47, p < 0.00001) [28]. In our research, we found that multivessel lesions group was more likely to have hypertension than single lesion group in ALDH2 wild genotype AMI patients.
With the continuous research of genes, single nucleotide polymorphisms can better explain the differences in individual phenotypes, disease susceptibility, and drug metabolism. The Hakka population is belong to Han Chinese population that have distinct characteristics of lifestyle, eating habits, cultural folklore and other characteristics that are distinct from other ethnic groups [29]. With the deepening of the research on the exact mechanism of ALDH2 gene and coronary angiography in the development of AMI, it will provide new ideas and therapeutic targets for AMI risk prediction and individualized treatment. The ALDH2 gene is only one of them, but the pathogenesis of coronary heart disease is complex, and it is involved by genetic and environmental factors. The mechanism of ALDH2 gene mutation and coronary vascular disease involved in the pathogenesis remains to be further studied. Besides, the study patients are too small, it is vital to expand the sample size to further explore.

Conclusions
The AMI patients in ethnic Hakka population carrying mutated ALDH2 allele was vulnerable to multiple coronary artery lesions. ALDH2 allele was associated with multiple coronary artery lesions in AMI patients among ethnic Hakka population. Abbreviations ALDH2: Aldehyde dehydrogenase 2; AMI: acute myocardial infarction ; SBP: systolic blood pressure; DBP: diastolic blood pressure; CREA: creatinine ; ALT: alanine transaminase; LM: left main disease; LAD: left anterior descending artery; LCX: left circum ex; RCA: right coronary artery; TG: triglyceride; TC: total cholesterol; HDL-C: high density lipoprotein cholesterol; LDL-C: low density lipoprotein cholesterol.

Declarations
Ethics approval and consent to participate The study was approved by the Ethics Committee of Meizhou People's Hospital, Meizhou Academy of Medical Sciences, Meizhou Hospital A liated to Sun Yat-sen University. We obtained individuals signed the written informed consents form before the study.

Consent for publication
Not applicable.

Con icts of interest
There are no con icts of interest.