Search

We aimed at associating common osteopontin (OPN) gene variants with cardiovascular disease phenotypes.We scanned the OPN gene in 190 chromosomes from myocardial infarction (MI) patients and identified five variants in the promoter, three synonymous and one non-synonymous variant. All variants were investigated in case–control studies for MI (ECTIM: 990 cases, 900 controls) and brain infarction (BI) (GENIC: 466 cases, 444 controls). Promoter variants were functionally analyzed by bandshift assays, the coding D147D [T/C] by Western blot. Allele D147D C was independently and significantly associated with lower apoB levels ( P =0.044 [ECTIM] P =0.03 [GENIC]), its allele frequency was significantly lower in patients with BI compared to controls (OR [95% CI] 0.39 [0.20–0.74], P =0.004), and C allele carriers had a significantly lower frequency of presence of carotid plaques ( P =0.02). Bandshifts with HepG2 and Ea.hy926 nuclear proteins did not reveal any functionality of promoter variants, whereas the OPN-441C-containing construct resulted in reduced OPN protein expression in Western blots, complying with its potential protective effect on the phenotypes studied.We here provide evidence that a portion of the OPN locus is likely to associate with cardiovascular disease-related phenotypes. However, further experiments are warranted to clarify the functional role of OPN variants.

Activation of type-1 dopamine receptors ( DRD1 ) reduces renal sodium reabsorption. In a family-based random sample of 611 untreated whites (women, 45.0%; mean age, 38.6 years), we measured blood pressure (BP). We used the endogenous lithium clearance to assess fractional sodium excretion (FE Na ) and proximal (RNa prox ) and distal (RNa dist ) tubular sodium reabsorption. We investigated multivariate-adjusted associations with the DRD1 promoter ( A − 48G , G − 94A , and C − 800T ) and GRK4 (Ala142Val ). The frequent DRD1 haplotypes were AGC (48.2%), GGT (34.4%), and AAC (14.3%). While standardizing to mean sodium excretion (8.7 mmol/h) and adjusting for covariates and relatedness, RNa dist was lower in DRD1 − 94GG homozygotes than − 94A allele carriers (effect size, −0.94%; P =0.005) with opposite findings for FE Na (+0.084%; P =0.014). AGC carriers (−0.88%; P =0.012) and AAC carriers (+1.00%; P =0.004) had different RNa dist compared to corresponding noncarriers. Furthermore, FE Na was lower in AAC carriers than in noncarriers (−0.082%; P =0.019). The family-based analyses identified a significant between-family component in the variance of the renal phenotypes associated with the DRD1 polymorphisms. Transmission of the DRD1 AGC haplotype was also associated with lower systolic (−3.54 mm Hg; P =0.016) and diastolic (−2.80 mm Hg; P =0.0064) BPs without significant between-family variance component. Plasma renin activity and urinary aldosterone excretion were not associated with DRD1 variation. The GRK4 Ala142Val polymorphism did not contribute to the phenotypes under study. In conclusion, renal sodium handling and BP were associated with genetic variation in the DRD1 promoter. The between-family variance component excluded population stratification for BP, but not for the renal phenotypes.

See related articles, pages 1109–1120. Cardiovascular disease (CVD), including coronary artery disease (CAD) with its fatal clinical outcome myocardial infarction (MI) and stroke, remain the leading cause of deaths in western and nonwestern countries.1,2 In the US, CVD claims more lives than cancer, chronic lower respiratory tract diseases and diabetes mellitus combined, accounting for ≈36% of all deaths in 2004 and incurring an estimated direct and indirect cost of ≈432 billion dollars in 2007.2 Stroke and MI are multifactorial traits with complex pathophysiology. Besides other established factors, family history of disease strongly and independently determines CVD risk.3 There is a nearly 5-fold difference in stroke risk between monocygotic and dizygotic twins,4 and with respect to race, stroke incidence is approximately twice as high in blacks compared to whites.5 Marenberg et al,6 in their study on ≈20 000 Swedish twins, demonstrated that the relative risk to die from MI, when the other twin already died from this disease, was twice as large for monozygotic compared to dizygotic twins. Celera Genomics7 and the International Human Genome Project consortium,8 by whole genome shotgun and clone-based sequencing strategies, respectively, proposed 2 versions of the human genome—the diploid genome offering more genetic information than previously anticipated.9 The availability of almost the entire human genome sequence allows for the immediate access to specific target sequences across the human genome. The number of different technologies to explore genetic sequences on a “genome-wide” scale and high-throughput genotyping methods is steadily increasing. Genome-wide approaches are essentially based on the fact that alleles at nearby loci often show strong linkage disequilibrium (LD). Human recombination events occur ubiquitously in short genomic hotspots (1 to 2 kb) every 100 to 200 kb, preferentially outside genes,10 leading to a breakdown of allelic …

Aims Identification and functional characterization of variants in the neutrophil elastase (ELA2) gene in cardiovascular disease. Methods From participants of the ECTIM (Etude Cas-Temoins sur l'infarctus du Myocarde) Study with myocardial infarction (Ml) 2082 chromosomes were genetically scanned; 990 patients with Ml and 904 controls were genotyped for the common polymorphisms G-761A and S173S (C4890A). Expression vectors for Ela2 variants were transiently transfected, followed by Northern and Western blot analyses. Promoter variants were analyzed by transfection/reporter gene assays. Results We identified 11 genetic variants, two in the 5'-flanking (G-761A, -852/del53bp), six in exons (R49H, N81N, G93V, S173S, D222Y, P228L) and three in introns (C+29/in3T, C+149/in3T, C+137/in4T). In Belfast, 4890A allele carriers had a risk for Ml with an odds ratio (OR) of 1.44 (95% Cl 1.12-1.86; P= 0.005), the OR for Ml associated with the - 761 G/-4890A haplotype with reference to -761G/-4890C amounting to 2.38 (95% Cl 1.23-4.57; P=0.01). Transcript or protein expression of both allelic constructs (4890A and 4890C) did not, however, differ. Conversely, transcriptional activity was significantly elevated (

Objective The SAH gene locus has recently been proposed to be involved in obesity-related hypertension in Japanese individuals. Methods To replicate independently the initial findings in another ethnic group, we scanned the entire SAH gene in 190 Caucasian chromosomes. A total of 651 patients with essential hypertension and 776 controls (PEGASE Study) were genotyped for all identified variants using allele-specific oligonucleotides, and single nucleotide polymorphism as well as haplotype analyses were carried out. We also performed transient transfection experiments, northern and western blots, immunoprecipitation, and acyl-coenzyme A synthetase activity assays. Results We identified five polymorphisms in the promoter region (C−1808T, G−1606A, −962ins/del, G−451A, T−67C), two in introns 5 and 7 (T+9/In5C, A+20/In7T), and one missense variant (K359N). Carriage of the −1606A allele was significantly associated with hypertension [odds ratio (OR) 1.28, P = 0.049] as was 359N (OR 1.35, P = 0.048) compared with non-carriers. Conversely, for −962del, the OR for hypertension was 0.80 (P = 0.042). The SAH alleles −1606A and 359N, but not −962ins/del, displayed a raising effect on body mass index (BMI; P = 0.004 and P = 0.030, respectively) in hypertensive as well as in control individuals. After adjustment for BMI in hypertensive individuals, only the OR associated with −962ins/del remained significant (OR 0.77, P = 0.028). Functional analyses in BHK did not reveal differences for SAH 359N or 359K-containing constructs, formally excluding K359N as the functional variant. Conclusion We confirm recent evidence that the SAH locus is associated with obesity-related hypertension, in which pathophysiological context SAH variants affecting blood pressure remain, however, to be shown.

Background and Purpose— Carotid intima-media thickness (IMT) reflects generalized atherosclerosis and is predictive of future vascular events. Evidence exists that carotid IMT is heritable, and genetic studies can provide clues in the pathogenesis of atherosclerosis. Methods— We recruited 470 white ischemic stroke patients, measured common carotid artery (CCA) IMT, and analyzed 54 polymorphisms with suspected roles in atherosclerosis. Results— Among the polymorphisms tested, the angiotensin-converting enzyme insertion/deletion, osteopontin (OPN) T-443C, monocyte chemoattractant protein-1 (MCP-1) G-927C, and MCP-1 A-2578G polymorphisms were associated with CCA–IMT in age-gender–adjusted analysis. In multivariate analysis, the association between the OPN and MCP-1 polymorphisms remained significant. The OPN-443C allele was associated with increased IMT in the dominant model (0.053 mm for the TC and CC genotypes; P =0.001). The MCP-1-927C allele was associated with increased IMT in the additive model (0.040 mm for each C allele; P =0.001), and the MCP-1-2578 G allele was associated with decreased IMT in the recessive model (0.088 mm for the GG genotype; P =0.002). Conclusions— The OPN and MCP-1 genes, coding for 2 cytokines with known roles in atherosclerosis, may contribute to increased carotid IMT and warrant further study.

Background The polymorphic angiotensinogen (AGT) gene is one of the most promising candidates for blood pressure (BP) regulation and essential hypertension. Objectives To investigate whether AGT haplotype analysis adds significant information compared to single polymorphism analysis with respect to different BP phenotypes in an untreated hypertensive sample. Methods Two hundred and twelve untreated hypertensive subjects of Caucasian origin were genotyped for the AGT polymorphisms C-532T, A-20C, C-18T, and G-6A. Results In single variant analyses, untreated hypertensives, carrying the AGT -532T or -6A alleles had significantly higher systolic blood pressure (SBP) and diastolic blood pressure (DBP), as well as ambulatory BP values compared to respective non-carriers. In haplotype-based analyses, combining all four AGT promoter variants, we demonstrate that AGT haplotypes containing different allele combinations at positions -532 and -6 were significantly associated with different BP values: (1) -532T and -6A with higher, (2) -532C and -6G with lower, (3) -532C and -6A with intermediate BP values. Since the result for the -532C/-20A/-18C/-6G haplotype was due to differences between non-carriers and carriers of this haplotype on both chromosomes, a recessive inheritance model for BP effects could be assumed. Conclusions Our results designate the C-532T and G-6A as the best candidates for functional studies on the AGT gene. Haplotype-based analyses should greatly aid in the dissection of the genetic basis of complex traits, such as BP regulation and hypertension.

International audience; To identify genetic susceptibility factors conferring increased risk of venous thrombosis (VT), we conducted a multistage study, following results of a previously published GWAS that failed to detect loci for developing VT. Using a collection of 5862 cases with VT and 7112 healthy controls, we identified the HIVEP1 locus on chromosome 6p24.1 as a susceptibility locus for VT. Indeed, the HIVEP1 rs169713C allele was associated with an increased risk for VT, with an odds ratio of 1.20 (95% confidence interval 1.13-1.27, p = 2.86 x 10(-9)). HIVEP1 codes for a protein that participates in the transcriptional regulation of inflammatory target genes by binding specific DNA sequences in their promoter and enhancer regions. The current results provide the identification of a locus involved in VT susceptibility that lies outside the traditional coagulation/fibrinolysis pathway.

Objective— Osteoprotegerin (OPG) has been reported to be involved in the development of atherosclerotic disease, and OPG gene variation has been associated with plasma OPG levels and different cardiovascular disease phenotypes. However, the genetic architecture of the OPG promoter and its transcriptional regulation are poorly characterized. Methods and Results— We identified 1008 bp of the OPG 5′-flanking region to be sufficiently transcriptionally active in osteosarcoma cell lines and generated serial promoter deletion constructs. Individual subcloning revealed the existence of 3 molecular haplotypes (MolHaps): [T −960 -A −946 -G −900 -T −864 ; MolHap1, wild type], [T −960 -G −946 -G −900 -T −864 ; MolHap2], [C −960 -G −946 -A −900 -G −864 ; MolHap4]. Compared to MolHap1, transcriptional activities of MolHaps 2 and 4 were significantly reduced ( P =0.0018). Whereas introduction of the −159C allele reduced transcriptional activities of the full-length constructs ( P =0.0014), it significantly increased activities of the deletion constructs ( P =0.0005). Electrophoretic mobility shift, competition, and chromatin immunoprecipitation assays revealed specific DNA:protein interactions for the MolHaps with Sp1 and NF-1, and identified Egr1 interacting exclusively with the −159T allele. Conclusions— We propose new structural and transcriptional features within the OPG promoter region and identified MolHaps being differentially transcriptionally active and allele-dependently interacting with a proximal polymorphic site.

Earlier studies have demonstrated the interaction between ADD1 and ACE in relation to arterial properties. We investigated whether arterial characteristics might also be related to interactions of ADD1 with other renin-angiotensin system genes. Using a family-based sampling frame, we randomly recruited 1064 Flemish subjects (mean age, 43.6 years; 50.4% women). By means of a wall-tracking ultrasound system, we measured the properties of the carotid, femoral and brachial arteries. In multivariate-adjusted analyses, we assessed the multiple gene effects of ADD1 (Gly460Trp), AGT (C-532T and G-6A) and AT1R (A1166C). In ADD1 Trp allele carriers, but not in ADD1 GlyGly homozygotes (P-value for interaction < or =0.014), femoral cross-sectional compliance was significantly higher (0.74 vs 0.65 mm(2) kPa(-1); P=0.020) in carriers of the AT1R C allele than in AT1R AA homozygotes, with a similar trend for femoral distensibility (11.3 vs 10.2 x 10(-3) kPa(-1); P=0.055). These associations were independent of potential confounding factors, including age. Family-based analyses confirmed these results. Brachial diameter (4.35 vs 4.18 mm) and plasma renin activity (PRA) (0.23 vs 0.14 ng ml(-1) h(-1)) were increased (P< or =0.005) in AGT CG haplotype homozygotes compared with non-carriers, whereas the opposite was true for brachial distensibility (12.4 vs 14.4 x 10(-3) kPa(-1); P=0.011). There was no interaction between AGT and any other gene in relation to the measured phenotypes. ADD1 and AT1R interactively determine the elastic properties of the femoral artery. There is a single-gene effect of the AGT promoter haplotypes on brachial properties and PRA. ispartof: Journal of Human Hypertension vol:23 issue:1 pages:55-64 ispartof: location:England status: published

Background The endothelin system (ES) plays an important role in blood pressure (BP) regulation and also in the pathophysiology of idiopathic dilated cardiomyopathy (DCM). Recently, we demonstrated that a genetic polymorphism in the endothelin A (ET A ) receptor gene was associated with survival in DCM patients. The aim of this study was to determine whether polymorphisms in the ET A receptor gene might be associated with the severity of DCM. Methods One hundred twenty-four consecutively recruited unrelated patients with DCM, who underwent a detailed phenotyping protocol, were genotyped for the ET A receptor G-231A polymorphism using a hybridization technique with allele-specific oligonucleotides. Results The exon 1 G-231A polymorphism of the ET A receptor gene, upstream of the translation start site, was significantly associated with directly measured intra-aortic pressure in that −231A allele carriers had significantly lower systolic ( P = .0043), as well as mean ( P = .0016) and diastolic ( P = .0041) aortic pressure compared to noncarriers. The association of ET A G-231A with aortic pressure was independent from other factors such as prior medication, left ventricular end-diastolic diameter, age, gender, and New York Heart Association (NYHA) functional classification. However, no such association was seen for cuff BP and survival rates were not significantly different between −231A allele carriers and −231G homozygotes (log rank test, P = .66). No significant association with any other parameter investigated in the present study could be observed, even when men and women were analyzed separately. Conclusions Our results suggest an association of genetic variation in the ET A receptor gene with aortic pressure in patients with DCM.