DNA repair gene XRCC1 and XPD polymorphisms and their association with coronary artery disease risks and micronucleus frequency

DNA damage response, a double-edged sword for vascular aging

Vascular aging is a major risk factor for age-related cardiovascular diseases, which have high rates of morbidity and mortality. It is characterized by changes in the blood vessels, such as macroscopically increased vascular diameter and intima-medial thickness, chronic inflammation, vascular calcification, arterial stiffening, and atherosclerosis. DNA damage and the subsequent various DNA damage response (DDR) pathways are important causative factors of vascular aging. Deficient DDR, which may result in the accumulation of unrepaired damaged DNA or mutations, can lead to vascular aging. On the other hand, over-activation of some DDR proteins, such as poly (ADP ribose) polymerase (PARP) and ataxia telangiectasia mutated (ATM), also can enhance the process of vascular aging, suggesting that DDR can have both positive and negative effects on vascular aging. Despite the evidence reviewed in this paper, the role of DDR in vascular aging and potential therapeutic targets remain poorly understood and require further investigation.

Polycyclic aromatic hydrocarbon and its effects on human health: An overeview

Polycyclic aromatic hydrocarbons (PAHs) are a class of chemicals of considerable environmental significance. PAHs are chemical contaminants of fused carbon and hydrogen aromatic rings, basically white, light-yellow, or solid compounds without color. Natural sources of pollution are marginal or less significant, such as volcanic eruptions, natural forest fires, and moorland fires that trigger lightning bursts. The significant determinants of PAH pollution are anthropogenic pollution sources, classified into four groups, i.e., industrial, mobile, domestic, and agricultural pollution sources. Humans can consume PAHs via different routes, such as inhalation, dermal touch, and ingestion. The Effect of PAHs on human health is primarily based on the duration and route of exposure, the volume or concentration of PAHs to which one is exposed, and the relative toxicity of PAHs. Many PAHs are widely referred to as carcinogens, mutagens, and teratogens and thus pose a significant danger to human health and the well-being of humans. Skin, lung, pancreas, esophagus, bladder, colon, and female breast are numerous organs prone to tumor development due to long-term PAH exposure. PAH exposure may increase the risk of lung cancer as well as cardiovascular disease (CVD), including atherosclerosis, thrombosis, hypertension, and myocardial infarction (MI). Preclinical studies have found a relationship between PAH exposure, oxidative stress, and atherosclerosis. In addition, investigations have discovered a relationship between PAH exposure at work and CVD illness and mortality development. This review aims to explain PAH briefly, its transportation, its effects on human health, and a relationship between environmental exposures to PAHs and CVD risk in humans.

Micronucleus assay for predicting coronary artery disease: A systematic review and meta-analysis

Coronary artery disease (CAD) is the leading cause of morbidity and mortality worldwide. Coronary angiography allows an accurate assessment of the extent and severity of atherosclerotic coronary narrowing, but it provides little characterization of early detection of potentially asymptomatic vulnerable plaque. The identification of the coronary "vulnerable patient" or high-risk plaques remains a major challenge in the treatment of CAD. Recently, growing evidence shows that DNA damage plays a role in the initiation and progression of atherosclerotic plaque. Cytokinesis-block micronucleus (CBMN) assay is one of the most frequently used and validated method for assessing chromosomal damage and genetic instability. Accordingly, the purpose of this systematic review was to retrieve and discuss existing literature on the studies assessing the association between MN and angiographically-proven CAD. A total of 8 studies published between 2001 and 2017 were included in the meta-analysis. Despite a large heterogeneity between studies (I²= 99.7 %, p < 0.0001), an overall increase of MN frequencies was found in patients with CAD compared with control group (meta-MR = 1.96; 95 % CI, 1.5-3.2, p = 0.009). A subgroup analysis showed an increase in the frequency of MN formation for both two- vessel (MR = 2.13, 95 % CI: 0.9-6.9, p = 0.08) and three-vessel disease (MR = 2.89, 95 % CI: 1.84-4.55, P = 0.06). Overall, the results of this meta-analysis provide evidence of an association between CBMN and presence, extent and severity of angiographically-assessed CAD. However, the small number of papers analyzed requires further large and more rigorously designed studies, carefully considering a series of clinical confounding factors, such as the quality of the metabolic control, the influence of drugs and radiation imaging treatments.

The relationship of micronucleus frequency and nuclear division index with coronary artery disease SYNTAX and Gensini scores

Objective:

We aimed to evaluate the relationship of micronucleus (MN) frequency and nuclear division index (NDI) with SYNTAX and Gensini scores and thrombolysis in myocardial infarction (TIMI) frame counts of coronary arteries in patients undergoing coronary angiography.

Methods:

In a single-center prospective observational study, a total of 63 individuals, 48 consecutive patients with coronary artery disease (CAD) and 15 healthy people were included. Before coronary angiography (exposure to X-ray), blood samples were collected for lymphocyte cultures, MN and NDI measurements. According to the SYNTAX and Gensini scores, patients were allocated into two groups. Group 1 and 2 included the patients with SYNTAX scores <22 and ≥22 points, respectively. Similarly, groups according to Gensini scores included the ones <23 and ≥23 points. MN test was used for in vitro studies in human peripheral lymphocytes. Binucleated lymphocytes were calculated for each patient.

Results:

MN frequency was significantly higher in group 2 than group 1 and in group 1 than control group (p<0.001). NDI was significantly higher in control group than group 1 and in group 1 than group 2 (p=0.003). MN frequency had positive but moderate correlation with SYNTAX and Gensini scores and TFCs of left anterior descending (LAD), circumflex and right coronary arteries (r=0.394, p=0.003; r=0.458, p<0.001; r=0.425, p<0.001; r=0.469, p<0.001; and r=0.475, p<0.001, respectively).

Conclusion:

We can conclude that as the degree of atherosclerosis increases and coronary flow worsens, MN frequency increases and NDI decreases. Our results may help to elucidate the relationship of DNA damage in pathophysiology of atherosclerosis and endothelial dysfunction in patients with stable CAD.

Associations between XRCC1 Gene Polymorphisms and Coronary Artery Disease: A Meta-Analysis

Genetic variations that influence DNA repair efficiency may contribute to coronary artery disease (CAD) susceptibility. Previous studies have investigated whether there was evidence of an association between polymorphisms at the X-ray repair cross complementing 1 (XRCC1) gene and susceptibility to CAD, but findings have been inconclusive. We identified eligible studies through a comprehensive literature search to determine whether an association exists between XRCC1 gene polymorphisms and CAD susceptibility. Findings were assessed using the odds ratio (OR) and corresponding 95% confidence interval (CI), which were calculated using a fixed- or random-effects model, based on the heterogeneity of the studies. Ten eligible studies were finally included in this meta-analysis. Our pooled analysis found that XRCC1 polymorphisms were significantly associated with CAD susceptibility under recessive (Arg194Trp: OR = 1.47, 95% CI = 1.13-1.93; Arg399Gln: OR = 1.45, 95% CI = 1.12-1.89), homozygous (Arg194Trp: OR = 1.37, 95% CI = 1.03-1.81; Arg399Gln: OR = 1.56, 95% CI = 1.19-2.05), and allele (Arg399Gln: OR = 1.18, 95% CI = 1.06-1.32) genetic models. Following subgroup analysis by ethnicity, in Asian populations, we found evidence of associations between the XRCC1 Arg194Trp polymorphism and CAD under recessive and homozygous genetic models, and between the XRCC1 Arg399Gln polymorphism and CAD under recessive, homozygous, and allele genetic models. Subgroup analysis stratified by control source revealed associations between the Arg194Trp and Arg399Gln polymorphisms and susceptibility to CAD under recessive and homozygous modes of inheritance, respectively. In addition, subgroup analysis stratified by sample size found that findings of the Arg194Trp polymorphism in large sample sizes were comparable to those found using pooled eligible studies. Based on our meta-analysis, we concluded that the XRCC1 gene polymorphisms, Arg194Trp and Arg399Gln, are associated with CAD susceptibility, specifically in Asian populations. However, additional, comprehensive and well-designed studies are warranted to confirm these findings.

The role of oxidative DNA damage and GSTM1, GSTT1, and hOGG1 gene polymorphisms in coronary artery disease risk

Objective:

Atherosclerotic coronary artery disease (CAD) appears to be a multifactorial process caused by the interaction of environmental risk factors with multiple predisposing genes. Therefore, in this study we aimed to determine the role of oxidative DNA damage and some variations in glutathione S-transferase (GSTM1 and GSTT1) and DNA repair (hOGG1) genes in CAD risk.

Methods:

A case-control study was conducted on 59 individuals who had undergone coronary angiographic evaluation. Of these, 29 were patients diagnosed with CAD (mean age =61.5±10.3) and 30 were controls examined for reasons other than suspected CAD and who had angiographically documented normal coronary arteries (mean age =60.4±11.6). Basal DNA damage as well as pyrimidine and purine base damage were evaluated in peripheral blood lymphocytes using the modified comet assay. Polymerase chain reaction-restriction length polymorphism (PCR-RFLP)-based assay was used for genotyping.

Results:

Basal DNA damage levels in patients [9.16 (3.26)] were significantly higher than those in controls [7.59 (3.23); p=0.017], and basal DNA and pyrimidine base damage levels were significantly correlated with disease severity based on Gensini scoring (r=0.352, p=0.006; r=0.318, p=0.014, respectively). However, no significant differences were observed in terms of oxidized DNA bases between patients and controls. The frequencies of studied genotypes (GSTM1, GSTT1, and hOGG1) were similar between groups.

Conclusion:

The results of this study pointed out the role of DNA damage in CAD and its severity. However, GSTM1, GSTT1, and hOGG1 gene polymorphisms seemed to have no effect on individual susceptibility for disease progression. (Anatol J Cardiol 2016; 16: 931-8)

Up-regulation of MSH2, XRCC1 and ATM genes in patients with type 2 diabetes and coronary artery disease

AIMS

Coronary artery disease (CAD) is a major problem in some patients with type 2 diabetes mellitus (T2DM). CAD has been suggested to be the main result of reduced efficacy of DNA repair systems. Analysis of the DNA repair system in patients with diabetes can potentially uncover the molecular basis of their susceptibility to the CAD. The aim of the present study was to compare the expression levels of some important DNA repair genes, including ATM, XRCC1 and MSH2, in CAD+ versus CAD- patients with T2DM. Furthermore, the relevance of putative single nucleotide polymorphisms (SNPs) in the promoter regions of these genes with mRNA expression was evaluated.

METHODS

Expression analysis was performed by RT-qPCR on 76 patients with T2DM (41 CAD+ and 35 CAD- individuals confirmed by angiography). The genotypes of the patients were examined by polymerase chain reaction-restriction fragment length polymorphism analysis.

RESULTS

Significant up-regulation of the MSH2 (2.49-fold, P=0.001), XRCC1 (2.11-fold, P=0.001) and ATM (2.15-fold, P=0.003) genes was observed in patients with T2DM and CAD. We could not detect any function for SNPs by comparing gene expression. In a receiver operating characteristic (ROC) curve analysis, the area under the ROC curve for sum of relative expressions of all genes reached 0.81 (95% CI: 0.690-0.936, P=0.003), which indicates a potential biomarker for identifying patients with T2DM and CAD.

CONCLUSION

These results suggest that expression levels of DNA repair genes may serve as informative biomarkers for identifying patients with T2DM and CAD.

The Effect of Polymorphisms in DNA Repair Genes and Carcinogen Metabolizers on Leukocyte Telomere Length: A Cohort of Healthy Spanish Smokers

INTRODUCTION

Smoking implies exposure to carcinogenic agents that causes DNA damage, which could be suspected to enhance telomere attrition. To protect and deal with DNA damage, cells possess mechanisms that repair and neutralize harmful substances. Polymorphisms altering DNA repair capacity or carcinogen metabolism may lead to synergistic effects with tobacco carcinogen-induced shorter telomere length independently of cancer interaction. The aim of this study was to explore the association between leukocyte telomere length (LTL) and several genetic polymorphisms in DNA repair genes and carcinogen metabolizers in a cohort of healthy smokers.

METHODS

We evaluated the effect of six genetic polymorphisms in cytochrome P1A1 (Ile462Val), XRCC1 (Arg399Gln), APEX1 (Asp148Glu), XRCC3 (Thr241Met), and XPD (Asp312Asn; Lys751Gln) on LTL in a cohort of 145 healthy smokers in addition to smoking habits.

RESULTS

Logistic regression analysis showed an association between XRCC1 399Gln allele and shorter telomere length (OR = 5.03, 95% CI = 1.08% to 23.36%). There were not association between the rest of polymorphisms analyzed and LTL.

CONCLUSIONS

Continuous exposure to tobacco could overwhelm the DNA repair machinery, making the effect of the polymorphisms that reduce repair capacity more pronounced. Analyzing the function of smoking-induced DNA-repair genes and LTL is an important goal in order to identify therapeutic targets to treat smoking-induced diseases.

Genetic variants in the DNA repair gene NEIL3 and the risk of myocardial infarction in a nested case-control study. The HUNT Study

BACKGROUND

Enhanced generation of reactive oxygen species and increased oxidative-induced DNA damage have been identified as possible contributors to atherosclerosis. The base excision repair (BER) pathway is the principal mechanism by which mammalian cells repair oxidative DNA damage. BER deficiency can potentially accelerate atherogenesis.

METHODS

We evaluated the association of Single Nucleotide Polymorphisms (SNPs) in genes encoding four different BER proteins (NEIL3, OGG1, APEX1 and XRCC1) with the incidence of myocardial infarction in a nested case-control study among participants of the second survey of the HUNT Study. The study population included 1624 cases and 4087 age- and sex-matched controls.

RESULTS

For the NEIL3 SNP rs12645561, the TT genotype was associated with increased risk of MI (OR 1.47, 95% CI 1.02-2.12, p uncorrected for multiple comparisons = 0.04) both in the genotypic test (compared to the CC genotype) and in the recessive genetic model (compared to the CC and CT genotypes combined). For the other two NEIL3 SNPs (rs10013040 and rs1395479) and for the SNPs of OGG1 (rs1052133), APEX1 (rs1878703) and XRCC1 (rs25489) we observed no association with risk of myocardial infarction.

CONCLUSION

We found that the NEIL3 rs12645561 SNP TT genotype was associated with increased risk of myocardial infarction. If confirmed in other studies, this association may suggest a possible role of attenuated DNA repair, and NEIL3 in particular, in atherogenesis.

Deoxyribonucleic acid repair gene X-ray repair cross-complementing group 1 polymorphisms and non-carcinogenic disease risk in different populations: A meta-analysis

PURPOSE

This study aims to assess a meta-analysis of the association of X-ray repair cross-complementing group 1 (XRCC1) polymorphisms with the risk of various non-carcinogenic diseases in different population.

MATERIALS AND METHODS

This meta-analysis was performed by critically reviewing reveals 38 studies involving 10043 cases and 11037 controls. Among all the eligible studies, 14 focused on Arg194Trp polymorphism, 33 described the Arg399Gln and three articles investigated on Arg280His. Populations were divided into three different ethnic subgroups include Caucasians, Asians and other (Turkish and Iranian).

RESULTS

Pooled results showed no correlation between Arg194Trp and non-carcinogenic disease. There was only weak relation in the recessive (odds ratio [OR] =1.11, 95% confidence interval [CI]: 0.86-1.44) model in Asian population and dominant (OR = 1.04, 95% CI: 0.66-1.63) model of other populations. In Arg399Gln polymorphism, there was no relation with diseases of interest generally. In the pooled analysis, there were weak relation in the dominant (OR = 1.08, 95% CI: 0.86-1.35) model of Asian population and quite well-correlation with recessive (OR = 1.49, 95% CI: 1.19-1.88), dominant (OR = 1.23, 95% CI: 0.94-1.62), and additive (OR = 1.23, 95% CI: 0.94-1.62) models of other subgroup. For Arg280His, there was a weak relation only in the dominant model (OR = 1.06, 95% CI: 0.74-1.51).

CONCLUSION

The present meta-analysis correspondingly shows that Arg399Gln variant to be associated with increased non-carcinogenic diseases risk through dominant and recessive modes among Iranian and Turkish population. It also suggests a trend of dominant and recessive effect of Arg280His variant in all population and its possible protective effect on non-carcinogenic diseases.

Meta-analysis of genetic polymorphisms and ophthalmologic disease risk in Asian populations: a case of DNA repair XRCC1 gene

This study aimed to assess a meta-analysis of the association of XRCC1 polymorphisms with the risk of various ophthalmologic diseases in Asian population. This meta-analysis was performed by critically reviewing reveals 38 studies involving 1373 cases and 1745 controls. Among all the eligible studies, one focused on Arg194Trp polymorphism, nine described the Arg399Gln and no article investigated on Arg280His. There was a large between-study heterogeneity in ORs of individual studies of the dominant model (chi2 = 74.18, I2 = 58.9%, p = 0.013) and the additive (chi2 = 56.18, I2 = 41.4%, p = 0.091) models, but a moderate heterogeneity in the recessive model (chi2 = 72.27, I2 = 78.8%, p = 0.000) was observed. So, we pooled the results using the random-effect analysis and found that Arg399Gln has a weak relation with ophthalmologic disease in the recessive (OR = 0.96, 95% CI: 0.64-1.44), the dominant (OR = 1.05, 95% CI: 0.82-1.33) and the additive (OR = 1.15, 95% CI: 0.77-1.70) and models. The present meta-analysis correspondingly shows that comprising diverse population is very important since susceptibility loci might vary indifferent ethnic groups. To ratify our findings, widespread studies with enlarged sample size and various populations are essential to explain the role of all polymorphism of XRCC1 genes in the pathogenesis of ophthalmologic diseases. Finally, our meta-analysis showed Arg399Gln variant was not associated with increased ophthalmologic diseases risk via dominant and recessive modes among Asian population.

Molecular studies on coronary artery disease-a review

Coronary artery disease (CAD) remains the major cause of mortality and morbidity in the entire world population. The conventional risk factors of CAD include hypertension, hyperlipidemia, diabetes mellitus, family history, smoking etc. These factors contribute only 50 % of the total risk of CAD. For providing a complete risk assessment in CAD, it is mandatory to have well-planned clinical, biochemical and genetic studies in patients with CAD and subjects who are at risk of developing CAD. In this review an attempt is made to critically evaluate the conventional and emerging risk factors which predispose the individual to CAD. Specifically, the molecular basis of CAD including high oxidative stress, low antioxidant status and increased DNA damage are covered. A comprehensive and multifactorial approach to the problem is the better way to reduce the morbidity and mortality of the disease.

Association between genetic variants of DNA repair genes and coronary artery disease

Polymorphisms in DNA repair genes may be associated with differences in the repair efficiency of DNA damage and may influence an individual's risk of atherosclerosis. Genetic research on coronary artery disease (CAD) has traditionally focused on investigation aimed at identifying disease-susceptibility genes. The aim of this study was to investigate the relationship between AP-endonuclease-1 (Asp148Glu), XRCC1 (Arg399Gln), XRCC3 (Thr241Met), XPD (Lys751Gln), XPG (Asp1104His), and hOGG1 (Ser326Cys), gene polymorphisms and the risk of developing CAD in a Turkish population. The study population consisted of 197 patients with acute coronary syndrome (ACS) with chronic CAD and 135 healthy subjects' age and sex matched. Gene polymorphisms were determined by the polymerase chain reaction-restriction fragment length polymorphism method. We demonstrated for the first time, a positive association of XRCC3 and hOGG1 DNA repair gene variants with CAD risk. XRCC3 Thr/Thr genotype and Thr allele frequencies were significantly increased in ACS and chronic CAD patients compared with the control group (p<0.05). It was also observed that there is a protective role of XRCC3 Met alleles against both ACS and chronic CAD (p<0.05). hOGG1 Cys alleles were found significantly higher in ACS patients than in the control group and carriers of the Cys allele had a 1.7-fold increased risk for ACS. In addition, we confirmed the association of XRCC3 Thr241Met and hOGG1 Ser326Cys gene variants with CAD by haplotype analysis. We found that CAD risk is associated with XRCC3 Thr: hOGG1 Cys haplotype, whereas XRCC3 Met: hOGG1 Ser haplotype was found to be protective against the disease. The preliminary results suggested that XRCC3 and hOGG1 genetic variants may be risk factors by affecting the enzyme's function that may lead to development of CAD.

DNA damage and repair in atherosclerosis: current insights and future perspectives

Atherosclerosis is the leading cause of morbidity and mortality among Western populations. Over the past two decades, considerable evidence has supported a crucial role for DNA damage in the development and progression of atherosclerosis. These findings support the concept that the prolonged exposure to risk factors (e.g., dyslipidemia, smoking and diabetes mellitus) leading to reactive oxygen species are major stimuli for DNA damage within the plaque. Genomic instability at the cellular level can directly affect vascular function, leading to cell cycle arrest, apoptosis and premature vascular senescence. The purpose of this paper is to review current knowledge on the role of DNA damage and DNA repair systems in atherosclerosis, as well as to discuss the cellular response to DNA damage in order to shed light on possible strategies for prevention and treatment.

XRCC1 gene variants and possible links with chromosome aberrations and micronucleus in active and passive smokers

Tobacco addiction is a major risk for diseases such as cancers, heart attack, etc. Tobacco smoke constitutes environmental toxins that are the major preventable leading cause of death worldwide. We investigated the influence of tobacco smoke on cytogenetic parameters (chromosomal aberrations and micronuclei) and the influence of XRCC1 arg399gln polymorphism on the cytogenetic parameters of the exposed subjects. The cases for this study include active and passive smokers. They were divided into three groups in accordance with duration of exposure to tobacco smoke. We observed changes in the frequency of chromosomal aberrations and micronuclei among the exposed subjects and controls. Of the three groups of exposed subjects, group III of active smokers and group III of passive smokers showed higher number of chromosomal aberrations and micronuclei when compared to controls, group I and group II of active and passive smokers. The XRCC1 arg399gln polymorphic variant gln/gln, influenced the extent of genotoxic damage in chromosomes and frequency of in micronuclei the three variants (arg/arg, arg/gln and gln/gln), gln/gln harbored significantly (P<0.05) higher number of aberrations than the arg/arg and arg/gln. In this context, the results observed in our study indicated that the single nucleotide polymorphism on XRCC1codon 399 influenced the frequencies of chromosomal aberrations and micronuclei.

The association of micronucleus frequency with obesity, diabetes and cardiovascular disease

Obesity and metabolic syndrome (MetS) are serious and growing health care problems worldwide, leading an increased risk for type 2 diabetes (T2D) and cardiovascular disease (CVD). Over the past decade, emerging evidence has shown that an increased chromosomal damage, as determined by the cytokinesis-block micronucleus (CBMN) assay, is correlated to the pathogenesis of metabolic and CVD. An increased micronuclei (MN) frequency has been demonstrated in peripheral blood lymphocytes of patients with polycystic ovary syndrome, a common condition in reproductive-aged women associated with impaired glucose tolerance, T2D mellitus and the MetS. High levels of MN have been detected to be significantly correlated with T2D as well as with the occurrence and the severity of coronary artery disease (CAD). Long-term follow-up studies have shown that an increased MN frequency is a predictive biomarker of cardiovascular mortality within a population of healthy subjects as well as of major adverse cardiovascular events in patients with known CAD. Overall, these findings support the hypothesis that CBMN assay may provide an useful tool for screening of the MetS and its progression to diabetes and CVD in adults as well in children. Large population-based cohorts are needed in order to compare the MN frequencies as well as to better define whether MN is a biomarker or a mediator of cardiometabolic diseases.

Oxidative stress, Helicobacter pylori, and OGG1 Ser326Cys, XPC Lys939Gln, and XPD Lys751Gln polymorphisms in a Turkish population with colorectal carcinoma

The contribution of polymorphisms of DNA repair genes OGG1 Ser326Cys, XPC Lys939Gln, and XPD Lys751Gln in developing colorectal carcinoma is controversial. Whether the group 1A carcinogen Helicobacter pylori is a risk factor or not in these patients could not be clearly elucidated. One hundred ten colorectal cancer patients and 116 cancer-free individuals constituted the test and control groups, respectively. The association of OGG1 Ser326Cys, XPC Lys939Gln, and XPD Lys751Gln polymorphisms and the susceptibility to colorectal carcinoma with or without oxidative stress were evaluated. DNA was extracted from peripheral blood cells and genotypes were determined using polymerase chain reaction-restriction fragment length polymorphism. For serum nitric oxide and total antioxidant status assay, spectrophotometric analyses were used. Serum albumin measurements were performed using an autoanalyzer. H. pylori IgG was measured by ELISA. The serum albumin concentrations of cancer patients were significantly lower than those of the controls (p < 0.05). The carriers of the variant genotype of OGG1 (odds ratio: 0.963; 95% confidence interval: 0.446-2.079), XPC (0.789, 0.366-1.700), or XPD (0.532, 0.259-1.094) did not associate with the increased risk of cancer progression, despite the increased oxidative stress in cancer patients. Seropositivity of H. pylori IgG has been found to increase the risk of colorectal carcinoma by 2.2-fold.

DNA repair gene polymorphism is associated with the genetic basis of atherosclerotic coronary artery disease

BACKGROUND

Atherosclerotic coronary artery disease (CAD) is a multifactorial process that appears to be caused by the interaction of environmental risk factors with multiple predisposing genes. It is nowadays accepted that increased levels of DNA damage induced by xenobiotics play an important role in the early phases of atherogenesis. Therefore, in this study, we focus on determining whether genetic variations in xenobiotic-metabolizing [glutathione-S-transferase theta 1 (GSTT1), glutathione-S-transferase mu 1 (GSTM1), cytochrome P450 IIEI (CYP2E1)] and DNA repair [X-ray cross-complementing group 1 (XRCC1)] genes might be associated with increased risk for CAD.

METHODS

A case-control study was conducted with 400 individuals who underwent subjected to coronary angiography. A total of 299 were patients diagnosed with effective coronary atherosclerosis (case group; >20% obstructive lesion), and 101 (control group) were individuals diagnosed as negative for CAD (<20% obstructive lesions). The polymorphism identifications for GSTM1 and GSTT1, and for CYP2E1 and XRCC1 genes were performed by polymerase chain reaction (PCR) amplification and by PCR-RFLP, respectively.

RESULTS AND CONCLUSIONS

The XRCC1 homozygous wild-type genotype Arg/Arg for codon 399 was statistically less pronounced in the case subjects (21.4%) than in controls (38.5%); individuals with the variant XRCC1 genotype had a 2.3-fold increased risk for coronary atherosclerosis than individuals with the wild-type genotype (OR=2.3, 95% CI=1.13-4.69). Conversely, no association between GSTM1, GSTT1, and CYP2E1gene polymorphisms and coronary atherosclerosis was detected. The results provide evidence of the role of DNA damage and repair in cardiovascular disease.

Plasma levels of copeptin in patients with coronary heart disease

The present study was undertaken to investigate alteration in plasma levels of copeptin, a stable fragment derived from provasopressin, in patients with coronary heart disease. We measured plasma level of copeptin in 21 patients with coronary heart disease (CHD) and 12 age-matched healthy subjects by radioimmunoassay (RIA). Chi-square test, Student's t-test and one-way analysis of variance were used for statistical analyses. Correlations between variables were tested by simple linear regression analysis. The plasma level of copeptin was significantly increased in patients (43.07 +/- 17.08 vs 11.13 +/- 5.73 pmol/l in controls, P < 0.01) and was further increased, by 60%, to 68.71 +/- 16.81 pmol/l on day 1 after therapy with percutaneous transluminal coronary angioplasty (PTCA) and stent (P < 0.05). On days 3 and 7 after therapy, the levels were greatly decreased, to 38.82 +/- 19.00 and 32.10 +/- 14.00 pmol/l, respectively, from that before therapy (all P < 0.05) but were higher, by 249% and 188%, respectively, than that of controls (all P < 0.01). The results suggest that the vasopressin system is activated in patients with CHD as indicated by changes in copeptin level, especially after PTCA and stent therapy. As a potential risk factor for CHD, plasma copeptin activation might have important clinical significance in terms of early intervention in patients with CHD.