Mikhail Churnosov

The C718T polymorphism in the 3′-untranslated region of glutathione peroxidase-4 gene is a predictor of cerebral stroke in patients with essential hypertension

In the present study we have investigated the association of three single nucleotide polymorphisms in glutathione peroxidase (GPx) genes GPX1 rs1050450 (P198L), GPX3 rs2070593 (G930A) and GPX4 rs713041 (T718C) with the risk of cerebral stroke (CS) in patients with essential hypertension (EH). A total of 667 unrelated EH patients of Russian origin, including 306 hypertensives (the EH–CS group) who suffered from CS and 361 people (the EH–CS group) who did not have cerebrovascular accidents, were enrolled in the study. The variant allele 718C of the GPX4 gene was found to be significantly associated with an increased risk of CS in hypertensive patients (odds ratio (OR) 1.53, 95% confidence interval (CI) 1.23–1.90, Padj=0.0003). The prevalence of the 718TC and 718CC genotypes of the GPX4 gene was higher in the EH–CS group than the EH-alone group (OR=2.12, 95%CI 1.42–3.16, Padj=0.0018). The association of the variant GPX4 genotypes with the increased risk of CS in hypertensives remained statistically significant after adjusting for confounding variables such as sex, body mass index (BMI), blood pressure and antihypertensive medication use (OR=2.18, 95%CI 1.46–3.27, P=0.0015). Multiple logistic regression analysis did not reveal any interaction between various combinations of GPX1, GPX3 and GPX4 genotypes regarding the risk of CS in patients with EH. The study demonstrated for the first time that the C718T polymorphism in the 3′-untranslated region of the GPX4 gene could be considered as a genetic marker of susceptibility to CS in patients with EH.

Transforming growth factor beta 1 is a novel susceptibility gene for adolescent idiopathic scoliosis.

Study Design. A genetic association study of the transforming growth factor beta 1 (TGFB1) gene with adolescent idiopathic scoliosis (AIS) in Russian population. Objective. To determine whether common genetic polymorphisms C-509T (rs1800469) and Arg25Pro (rs1800471) of the TGFB1 gene are associated with susceptibility to AIS. Summary of Background Data. An importance of growth factors for the pathogenesis of AIS has been demonstrated by the findings of abnormal expression of these proteins in the spine and surrounding tissues in patients with AIS. However, no studies have been performed to investigate the relationship between genetic polymorphisms of the TGFB1 gene and susceptibility to AIS. Methods. A total of 600 unrelated adolescents from Central Russia (Moscow) were recruited in this study, including 300 patients with AIS and 300 age- and sex-matched healthy adolescents. The polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism. Results. The allele -509T and genotype -509TT of the TGFB1 gene were significantly associated with the increased risk of idiopathic scoliosis in both females and males (P < 0.01). Logistic regression analysis has revealed a recessive model of the genetic association between polymorphism C-509T of the TGFB1 gene and AIS. Moreover, we found sexual dimorphisms in the relationships of SNP C-509T of the TGFB1 gene with both the age of disease onset and curve severity: the polymorphism was found to determine both an early onset of scoliosis and the severity of curvature in females but not in males (P < 0.05). Conclusion. This study, for the first time, highlights the importance of TGFB1 gene for the development and progress of AIS. We hypothesize several mechanisms by which the TGFB1 gene may contribute to spinal deformity in patients with AIS.

The Flavin-Containing Monooxygenase 3 Gene and Essential Hypertension: The Joint Effect of Polymorphism E158K and Cigarette Smoking on Disease Susceptibility

Gene encoding flavin-containing monooxygenase 3 (FMO3), a microsomal antioxidant defense enzyme, has been suggested to contribute to essential hypertension (EH). The present study was designed to investigate whether common functional polymorphism E158K (rs2266782) of the FMO3 gene is associated with EH susceptibility in a Russian population. A total of 2 995 unrelated subjects from Kursk (1 362 EH patients and 843 healthy controls) and Belgorod (357 EH patients and 422 population controls) regions of Central Russia were recruited for this study. DNA samples from all study participants were genotyped for the FMO3 gene polymorphism through PCR followed by RFLP analysis. We found that the polymorphism E158K is associated with increased risk of essential hypertension in both discovery population from Kursk region (OR 1.36 95% CI 1.09–1.69, P = 0.01) and replication population from Belgorod region (OR 1.54 95% CI 1.07–1.89, P = 0.02) after adjustment for gender and age using logistic regression analysis. Further analysis showed that the increased hypertension risk in carriers of genotype 158KK gene occurred in cigarette smokers, whereas nonsmoker carriers of this genotype did not show the disease risk. This is the first study reporting the association of the FMO3 gene polymorphism and the risk of essential hypertension.

Smoking Status Modifies the Relation Between CYP1A1*2C Gene Polymorphism and Idiopathic Male Infertility: The Importance of Gene–Environment Interaction Analysis for Genetic Studies of the Disease

The study was designed to investigate the associations of polymorphisms Ile462Val and 3801T>C of the cytochrome P450 1A1 (CYP1A1) gene with idiopathic male infertility (IMI) and to assess the impact of smoking status on the relationship between the polymorphisms and the susceptibility to the disease. DNA samples from 203 patients with IMI and 227 fertile men were genotyped for the polymorphisms by a polymerase chain reaction and restriction fragment length polymorphism methods. We found for the first time that the increased risk of IMI in carriers of genotype 462Ile/Val of the CYP1A1 gene occurred only in smoker men (odds ratio [OR] = 1.91; 95% confidence interval [CI] 1.01-3.59), whereas nonsmoker men did not have the risk of infertility (OR = 1.58; 95% CI 0.66-3.76). The results of our study demonstrate that the analysis of gene–environment interactions is necessary to explain conflicting results of genetic studies of IMI and to improve our understanding of the mechanisms of the disease.

The insertion-deletion polymorphism of the ACE gene is associated with increased blood pressure in women at the end of pregnancy

Introduction: Malfunctioning of the cardiovascular system during pregnancy may be responsible for adverse effects on the ‘mother-fetus’ system. The cardiovascular system of a pregnant woman develops adaptation to the increased load. Angiotensin-converting enzyme (ACE) is known to play an important role in the adaptation. The present study was designed to investigate whether the insertion-deletion (I/D) polymorphism of the ACE gene is associated with the level of arterial blood pressure in women before and during pregnancy. Materials and methods: The level of blood pressure was measured in 591 Russian women (Central Russia) before and during (37–40 weeks term) pregnancy. The women were divided into three groups which were hypertensive, hypotensive, and normotensive according to blood pressure level. Genotyping of the ACE I/D polymorphism was performed using polymerase chain reaction (PCR) and amplified fragment length polymorphism assay. Results: Women with genotype DD showed the highest blood pressure level both during and at the end of pregnancy (p<0.05). The highest frequencies of allele D and genotype DD were found in pregnant women in the hypertensive group. Conclusions: The deletion variant of the ACE gene is associated with high blood pressure level at the end of pregnancy.

A comprehensive contribution of genes for aryl hydrocarbon receptor signaling pathway to hypertension susceptibility

Objective The present study was designed to investigate whether genetic polymorphisms of the aryl hydrocarbon receptor (AHR) signaling pathway are involved in the molecular basis of essential hypertension (EH). Methods A total of 2160 unrelated Russian individuals comprising 1341 EH patients and 819 healthy controls were recruited into the study. Seven common AHR pathway single-nucleotide polymorphisms (SNPs) such as rs2066853, rs2292596, rs2228099, rs1048943, rs762551, rs1056836, and rs1800566 were genotyped by TaqMan-based allele discrimination assays. Results We found that SNP rs2228099 of ARNT is associated with an increased risk of EH (odds ratio=1.20 95% confidence interval: 1.01–1.44, P=0.043) in a dominant genetic model, whereas polymorphism rs762551 of CYP1A2 showed an association with a decreased risk of disease in a recessive genetic model (odds ratio=0.68, 95% confidence interval: 0.52–0.89, P=0.006). A log-likelihood ratio test enabled identification of epistatic interaction effects on EH susceptibility for all SNPs. MB-MDR analysis showed that cigarette smoking, rs1048943, rs762551, rs1056836, and rs2228099 were significant contributing factors in 19, 18, 13, 13, and 11 interaction models, respectively. The best MDR model associated with EH risk included rs1048943, rs762551, rs1056836, and cigarette smoking (cross-validation consistency 100%, prediction error 45.7%, Ppermutation<0.0001). The mRNA expression and in-silico function prediction analyses have confirmed a regulatory potential for a majority of SNPs associated with EH susceptibility. Conclusion Our pilot study was the first to show that gene–gene and gene–environment interactions in the AHR signaling pathway represent important determinants for the development of EH, and the pathway may become an attractive target for a pharmacological intervention in hypertensive patients in the future.

Synergism between the N-acetyltransferase 2 gene and oxidant exposure increases the risk of idiopathic male infertility

N-acetyltransferase (NAT2) is a phase-II xenobiotic-metabolizing enzyme participating in the detoxification of toxic arylamines, aromatic amines and hydrazines. The present study was designed to investigate whether two common single-nucleotide polymorphisms (SNP) of the NAT2 gene (481C>T, rs1799929; 590G>A, rs1799930) are associated with susceptibility to idiopathic male infertility and to assess if the risk is modified by oxidant and antioxidant exposures. A total 430 DNA samples (203 infertile patients and 227 fertile men) were genotyped for the polymorphisms by PCR and restriction fragment length polymorphism. No association was found between the NAT2 polymorphisms and idiopathic male infertility. However, gene-environment interaction analysis revealed that a low-acetylation genotype, 590GA, was significantly associated with increased disease risk in men who had environmental risk factors such as cigarette smoking (OR 1.71, 95% CI 1.02-2.87, P = 0.042), alcohol abuse (OR 2.14, 95% CI 1.08-4.27, P = 0.029) and low fruit/vegetable intake (OR 1.68, 95% CI 1.01-2.79, P = 0.04). This pilot study found, as far as is known for the first time, that the polymorphism 590G>A of NAT2 is a novel genetic marker for susceptibility to idiopathic male infertility, but the risk is potentiated by exposure to various environmental oxidants.

Genes involved in the regulation of vascular homeostasis determine renal survival rate in patients with chronic glomerulonephritis

Chronic glomerulonephritis (CGN) is one of the most severe kidney diseases. Genes of vascular reactivity are thought to play an important role in development and progression of CGN. In this study, we analyzed association of genes of vascular homeostasis with hypertension and renal survival of CGN patients. The study sample included 238 patients with CGN and 304 healthy subjects of population control. Ten polymorphisms of ten genes of vascular homeostasis were genotyped through polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP) analysis and TaqMan assays. Association of the genotypes with renal survival was analyzed by the Kaplan-Meier estimator. Genotypes 311SC and 311SS of the PON2 gene, (-1166)AC and (-1166)CC of the AGTR1 gene, (+46)AA of the ADRB2 gene, and 198KK and 198KN of the EDN1 gene were associated with decreased rate of renal survival of the patients. Polymorphisms S311C PON2, (-1166)A/C AGTR1, (+46)G/A ADRB2, and K198N EDN1 were associated with the accelerated decline in kidney function in the CGN patients.

Altered erythrocyte membrane protein composition mirrors pleiotropic effects of hypertension susceptibility genes and disease pathogenesis.

Objective: The study was designed to assess the effects of polymorphisms in genes associated with essential hypertension on the variation of erythrocyte membrane proteins (EMPs) in hypertensive patients. Methods: Major EMPs content was analyzed in blood from 1162 unrelated Russians (235 hypertensive patients, 176 healthy controls, and 751 random individuals from the Central Russia population). Essential hypertension patients were genotyped for 11 polymorphisms of essential hypertension susceptibility genes including ADD1 (rs4961), GNB3 (rs5443, rs16932941), NOS3 (rs1799983, rs2070744), ACE (rs5186), AGTR1 (rs5186), AGT (rs699, rs4762), MR (rs5534), and TGFB1 (rs1800471). EMP contents and their relationship with the genetic loci were analyzed using various statistical tests. Results: Sex-specific differences in EMP contents between the cases and controls were observed. Regardless of sex, hypertensives exhibited mainly decreased levels of alpha (SPTA1) and beta-spectrin (SPTB) and increased levels of glucose transporter (GLUT1) as compared with healthy subjects (P ⩽ 0.001). EMP correlated differently in essential hypertension patients and controls. Almost 70% of the joint variation in the EMP levels is explained by five gender-specific principal components. The essential hypertension susceptibility genes showed considerable effects on the levels of spectrins and glucose transporter. A joint variation of the genes explained about half the total polygenic variance in the GLUT1, SPTA1, and SPTB levels in hypertensives. Conclusions: The study showed that essential hypertension susceptibility genes are the important factors of the inherited EMP variation, and their pleitropic effects may be mirrored in the altered expression of genes encoding cytoskeletal proteins and those related to intracellular glucose metabolism.

Polymorphisms of CYP2C8, CYP2C9 and CYP2C19 and risk of coronary heart disease in Russian population

Epoxyeicosatrienoic acids (EETs) are important vasoactive products of arachidonic acid metabolism with a wide range of biological actions in the cardiovascular system. The present study investigated whether single nucleotide polymorphisms (SNP) of genes coding cytochrome P450 2C subfamily, enzymes involved in biosynthesis of EETs, are associated with the risk of coronary heart disease (CHD). A total of 1255 unrelated Russian subjects comprising 561 patients with angiographically diagnosed CHD and 694 age- and sex-matched healthy subjects were included in the study. DNA samples from all study participants were genotyped for six common SNPs rs7909236, rs1934953 of CYP2C8, rs9332242, rs4918758 and rs61886769 of CYP2C9 and rs4244285 of CYP2C19 using by the Mass-ARRAY 4 system. SNP rs4918758 of CYP2C9 was associated with decreased risk of CHD (codominant model) at a borderline significance with odds ratio adjusted for sex and age 0.61 (95% CI: 0.41-0.92, P=0.038, Q=0.20). SNP rs9332242 of CYP2C9 showed a trend towards association with increased CHD risk in cigarette smokers (P=0.049, Q=0.29). Log-likelihood ratio test (LRT) pointed out epistatic interactions between rs9332242 and rs61886769 of CYP2C9 (codominant model, Pinteraction=0.02), however, this P-value did not survive after correction for multiple tests. Bioinformatic analysis revealed a regulatory potential for a majority of the investigated SNPs. Our preliminary results demonstrate that polymorphisms of genes encoding CYP2C subfamily represent potential genetic markers of CHD susceptibility. Further studies are required to substantiate the contribution of these genes to the disease risk.