Bone morphogenetic proteins protect pulmonary microvascular endothelial cells from apoptosis by upregulating α-B-crystallin.

OBJECTIVE: To investigate the role of bone morphogenetic proteins (BMPs) on α-B-crystallin (CRYAB) expression and its physiological consequences on endothelial cells (ECs). APPROACH AND RESULTS: We report that the gene encoding for the small heat shock protein, CRYAB, is a transcriptional target of the BMP signaling pathway. We demonstrate that CRYAB expression is upregulated strongly by BMPs in an EC line and in human lung microvascular ECs and human umbilical vein ECs. We show that BMP signals through the BMPR2-ALK1 pathway to upregulate CRYAB expression through a transcriptional indirect mechanism involving Id1. We observed that the known antiapoptotic effect of the BMPs is, in part, because of the upregulation of CRYAB expression in EC. We also show that cryab is downregulated in vivo, in a mouse model of pulmonary arterial hypertension induced by chronic hypoxia where the BMP pathway is downregulated. CONCLUSIONS: We demonstrate a cross-talk between BMPs and CRYAB and a major effect of this regulatory interaction on resistance to apoptosis.

Small platelet microparticle levels are increased in pulmonary arterial hypertension.

BACKGROUND: The various aetiologies and risk factors for pulmonary arterial hypertension (PAH) lead to close phenotypes with small differences. Plasma microparticles have been shown to be increased in vascular pathologies including PAH. The aim of this study was to determine whether the levels of endothelial and platelet-derived microparticles could vary between different forms of PAH: idiopathic PAH (iPAH), heritable PAH associated with BMPR2 (Bone morphogenetic protein receptor, type II) mutation (hPAH) and PAH associated with connective tissue diseases (aPAH). MATERIALS AND METHODS: Microparticles were analysed using flow cytometry in plasma from controls and iPAH, hPAH and aPAH patients. Platelet-derived MP (PMP) were defined as CD31(+)/CD41(+) and endothelial-derived MP (EMP) as CD31(+)/CD41(-). Two populations of PMP were isolated according to their size, defining small PMP (0·3-0·5 µm) and large PMP (0·5-0·9 µm). BMPR2 genotype, clinical and biologic parameters were recorded. RESULTS: EMP and small PMP levels in iPAH, hPAH and aPAH were similar and were significantly increased as compared with controls. No differences in large PMP levels were observed. After adjusting for age, sex, proBNP and CRP, EMP and small PMP levels did not correlate with clinical parameters. CONCLUSIONS: iPAH, hPAH and aPAH were characterized by increased levels of EMP and of small PMP, a new class of PMP which seems to be differentially produced than large PMP.

Inhibition of apelin expression by BMP signaling in endothelial cells.

The transforming growth factor-ß/bone morphogenic protein (BMP) system is a major pathway for angiogenesis and is involved in hereditary vascular diseases. Here we report that the gene encoding the vasoactive and vascular cell growth-regulating peptide apelin is a target of the BMP pathway. We demonstrate that apelin expression is strongly downregulated by BMP in an endothelial cell line as well as in lung endothelial microvascular cells. We show that BMP signals through the BMPR2-SMAD pathway to downregulate apelin expression and that a transcriptional direct and indirect mechanism is required. The BMP-induced downregulation of apelin expression was found to be critical for hypoxia-induced growth of endothelial cells, because the growth inhibitory effect of BMP in this condition is suppressed by enforced expression of apelin. Thus, we describe an important link between a signaling pathway involved in angiogenesis and vascular diseases and a peptide regulating vascular homeostasis.

Plasticity-related gene-1 inhibits lysophosphatidic acid-induced vascular smooth muscle cell migration and proliferation and prevents neointima formation.

Plasticity-related gene-1 (PRG-1) protects neuronal cells from lysophosphatidic acid (LPA) effects. In vascular smooth muscle cells (VSMCs), LPA was shown to induce phenotypic modulation in vitro and vascular remodeling in vivo. Thus we explored the role of PRG-1 in modulating VSMC response to LPA. PCR, Western blot, and immunofluorescence experiments showed that PRG-1 is expressed in rat and human vascular media. PRG-1 expression was strongly inhibited in proliferating compared with quiescent VSMCs both in vitro and in vivo (medial vs. neointimal VSMCs), suggesting that PRG-1 expression is dependent on the cell phenotype. In vitro, adenovirus-mediated overexpression of PRG-1 specifically inhibited LPA-induced rat VSMC proliferation and migration but not platelet-derived growth factor-induced proliferation. This effect was abolished by mutation of a conserved histidine in the lipid phosphate phosphatase family that is essential for interaction with lipid phosphates. In vivo, balloon-induced neointimal formation in rat carotid was significantly decreased in vessels infected with PRG-1 adenovirus compared with ß-galactosidase adenovirus (-71%; P < 0.05). PRG-1 overexpression abolished the activation of the p42/p44 signaling pathway in LPA-stimulated rat VSMCs in culture and in balloon-injured rat carotids. Taken together, these findings provide the first evidence of a protective role of PRG-1 in the vascular media under pathophysiological conditions.

Performance comparison of two microarray platforms to assess differential gene expression in human monocyte and macrophage cells.

BACKGROUND: In this study we assessed the respective ability of Affymetrix and Illumina microarray methodologies to answer a relevant biological question, namely the change in gene expression between resting monocytes and macrophages derived from these monocytes. Five RNA samples for each type of cell were hybridized to the two platforms in parallel. In addition, a reference list of differentially expressed genes (DEG) was generated from a larger number of hybridizations (mRNA from 86 individuals) using the RNG/MRC two-color platform. RESULTS: Our results show an important overlap of the Illumina and Affymetrix DEG lists. In addition, more than 70% of the genes in these lists were also present in the reference list. Overall the two platforms had very similar performance in terms of biological significance, evaluated by the presence in the DEG lists of an excess of genes belonging to Gene Ontology (GO) categories relevant for the biology of monocytes and macrophages. Our results support the conclusion of the MicroArray Quality Control (MAQC) project that the criteria used to constitute the DEG lists strongly influence the degree of concordance among platforms. However the importance of prioritizing genes by magnitude of effect (fold change) rather than statistical significance (p-value) to enhance cross-platform reproducibility recommended by the MAQC authors was not supported by our data. CONCLUSION: Functional analysis based on GO enrichment demonstrates that the 2 compared technologies delivered very similar results and identified most of the relevant GO categories enriched in the reference list.

Thrombomodulin gene polymorphisms in brain infarction and mortality after stroke.

BACKGROUND AND PURPOSE: Thrombomodulin is expressed at the surface of endothelial cells and controls thrombin generation and thrombin-induced platelets and vascular cell activation. Several thrombomodulin gene polymorphisms have been associated with coronary events and brain infarction. In a previous analysis from the Etude du Profil Génétique de l'Infarctus Cérébral (GENIC) study, we found that soluble thrombomodulin (sTM) concentration modulated the risk of and prognosis for brain infarction. METHODS: In 474 brain infarction cases and 483 controls from the GENIC study, we investigated the relationship between three thrombomodulin gene polymorphisms (-1748G/C, -1208/-1209delTT, +1418C/T) and sTM levels, brain infarction risk and 5-year mortality after stroke. RESULTS: The three polymorphisms were in linkage disequilibrium and defined three major haplotypes with no influence on sTM concentration (all P values > 0.16). Single locus and haplotype analyses found no significant association with brain infarction, even when the analysis was restricted to individuals without a vascular history. After 5 years of follow-up, we found no relationship with vascular or total mortality (all P values > 0.64). CONCLUSION: Our results suggest that these three thrombomodulin gene polymorphisms do not contribute to sTM level variations and are not associated with risk of brain infarction and mortality after stroke.

The renin-angiotensin-aldosterone system in cerebral small vessel disease.

INTRODUCTION: Cerebral small vessel disease (SVD) appears on magnetic resonance imaging (MRI) as leukoaraiosis (LA), état criblé (EC), and multiple lacunar infarctions (MLI). Although the pathophysiology of SVD is poorly understood, there is evidence of a genetic contribution. We sought to analyze the influence of the renin-angiotensin-aldosterone system (RAAS) on SVD in symptomatic patients from the Génétique de l'Infarctus Cérébral (GENIC) study, including RAAS polymorphisms and circulating angiotensin converting enzyme (ACE). METHODS: Caucasian patients (n=510) with acute brain infarction (BI) were recruited and MRIs were evaluated for SVD, including LA, EC, and MLI. We considered ACE levels and several polymorphisms, including ACE, angiotensinogen, aldosterone synthase CYP11B2, and angiotensin II receptor type I. RESULTS: Among the polymorphisms, there were marginal negative associations between aldosterone synthase CYP11B2 -344C against severe EC (adjusted OR, 0.57; 95% CI, 0.31-1.05) and severe LA (adjusted OR, 0.54; 95% CI, 0.30-0.95), both considering -344C dominant. In addition, the frequency of -344C decreased with the number of SVD abnormalities (p=0.016). Mean plasma ACE was elevated in patients with MLI, but not with LA or EC. The risk of MLI increased gradually with increasing plasma ACE (adjusted OR, 1.25; 95% CI, 1.02-1.53). CONCLUSIONS: This exploratory study found no strong evidence for RAAS involvement in severe SVD in this population. The whole spectrum of SVD, including EC, MLI, and LA, can be considered as phenotypes for genetic studies.

Haplotypes of the caspase-1 gene, plasma caspase-1 levels, and cardiovascular risk.

Caspase-1 processes the interleukin (IL)-1beta and IL-18 inactive precursors to the biologically active cytokines that are known to have proatherogenic effects. The present study investigated the genetic variability of the CASP1 gene and plasma levels of caspase-1 in relation to cardiovascular risk. In Europeans, 3 tag SNPs captured 4 common haplotypes of the CASP1 gene. Among these, the A(in6) allele of the G+7/in6A polymorphism was less frequent in 246 cases with myocardial infarction and a parental history of disease than in 253 controls free of familial history of disease (0.13+/-0.02 versus 0.20+/-0.02; P=0.005). However, in a larger case/control study (n=1774), these effects are borderline restricted to the UK population. In a prospective cohort of 1168 patients with coronary artery disease followed up during a median period of 6.0 years, the A(in6) allele exhibited a borderline association with future cardiovascular death (hazard ratio [HR]: 0.64, 0.41 to 1.01; P=0.053) and was associated with lower serum IL-18 levels (P=0.014). Baseline caspase-1 levels in the top quartile of the distribution were predictive of cardiovascular deaths (HR=3.62, 1.81 to 7.27; P=0.0003 compared with the bottom quartile). Finally, in vitro assays of allelic imbalance showed that the CASP1 haplotype carrying the A(in6) allele was associated with a lower mRNA expression. These results indicate that caspase-1 levels are predictive of future cardiovascular death in patients with coronary artery disease. The role of CASP1 genetic variations in the susceptibility to myocardial infarction requires further investigation.

Polymorphisms in 33 inflammatory genes and risk of myocardial infarction--a system genetics approach.

The hypothesis of a causal link between inflammation and atherosclerosis would be strengthened if variants of inflammatory genes were associated with disease. Polymorphisms of 33 genes encoding inflammatory molecules were tested for association with myocardial infarction (MI). Patients with MI and a parental history of MI (n = 312) and controls from the UK (n = 317) were genotyped for 162 polymorphisms. Thirteen polymorphisms were associated with MI (P values ranging from 0.003 to 0.041). For three genes, ITGB1, SELP, and TNFRSF1B haplotype frequencies differed between patients and controls (P values < 0.01). We further assessed the simultaneous contribution of all polymorphisms and relevant covariates to MI using a two-step strategy of data mining relying on Random Forest and DICE algorithms. In a replication study involving two independent samples from the UK (n = 649) and France (n = 706), one interaction between the ITGA4/R898Q polymorphism and current smoking status was replicated. This study illustrates a strategy for assessing the joint effect of a large number of polymorphisms on a phenotype that may provide information that single locus or single gene analysis may fail to uncover. Overall, there was weak evidence for an implication of inflammatory polymorphisms on susceptibility to MI.

Differential haplotypic expression of the interleukin-18 gene.

Interleukin 18 (IL-18) is suspected to play an important role in atherosclerosis and plaque vulnerability. We had previously shown that haplotypes combining two IL18 gene polymorphisms in complete linkage disequilibrium, C-105T (rs360717) in 5'-untranslated region (UTR) and A+183G (rs5744292) in 3'-UTR, were related to IL-18 circulating levels and cardiovascular outcome, the C(-105) G(+183) haplotype being associated with lower IL-18 levels and lower cardiovascular risk. This study was aimed at investigating the functional role of the two polymorphisms and their haplotypes on IL18 expression levels. Allelic imbalance experiments conducted in 24 and 20 subjects heterozygous for the C-105T and the A+183G polymorphisms did not detect any difference when subjects were considered as a whole (-0.009+/-0.044, P=0.85 and +0.114+/-0.082, P=0.18, respectively). However, when splitting individuals according to their haplo-genotype, the haplotype C(-105) G(+183) was associated with a lower expression level than C(-105) A(+183) (-0.287+/-0.076, P=0.005), but did not differ from T(-105) A(+183) (-0.138+/-0.083, P=0.13). The lower expression associated with C(-105) G(+183) was confirmed by real-time reverse transcription-PCR. Transfection of different haplotypic versions of the 3'-UTR did not show any difference in the expression of an upstream reporter gene. A 10-h study of the mRNA degradation kinetics by allelic imbalance with the A+183G polymorphism did not show any differential allelic degradation. In conclusion, the haplotype associated with lower IL-18 circulating concentrations and a lower cardiovascular risk was consistently associated with decreased IL18 expression levels, although the exact functional mechanisms remain to be elucidated.

Genetic analysis of the interleukin-18 system highlights the role of the interleukin-18 gene in cardiovascular disease.

BACKGROUND: Interleukin (IL)-18 plays a key role in atherosclerosis and its complications. The present study investigated the genetic variability of 4 genes of the IL-18 system-IL18, IL18R1, IL18RAP, and IL18BP-in relation to circulating IL-18 levels and cardiovascular mortality. METHODS AND RESULTS: Twenty-two polymorphisms were genotyped in 1288 patients with coronary artery disease prospectively followed up during a median period of 5.9 years. The end point was death from cardiovascular causes (n=142). Baseline IL-18 levels were predictive of cardiovascular deaths occurring during < or =4 years of follow-up (HR=2.96, 95% CI 1.54 to 5.70, P=0.001 for the top compared with the bottom quartile) but not of later deaths. Haplotypes of the IL18 gene were associated with IL-18 levels (P=0.002) and cardiovascular mortality (P=0.006) after adjustment for cardiovascular risk factors. The same haplotype was associated with both a 9% lowering effect on IL-18 levels and a protective effect on risk (HR=0.57, 95% CI 0.36 to 0.92). IL18 haplotypes explained only 2% of IL-18 variability. Adjustment for baseline IL-18 levels abolished the association of haplotypes with cardiovascular risk. The haplotype associated with phenotypes was the only one carrying the minor allele of the IL18/A+183G polymorphism located in the 3'untranslated region and potentially affecting mRNA stability. The other genes of the system were not related to IL-18 levels or cardiovascular outcome. CONCLUSIONS: Variations of the IL18 gene consistently influence circulating levels of IL-18 and clinical outcome in patients with coronary artery disease, which supports the hypothesis of a causal role of IL-18 in atherosclerosis and its complications.

Cytokine polymorphisms associated with carotid intima-media thickness in stroke patients.

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.

Gene polymorphisms of the renin-angiotensin system and early development of hypertension.

BACKGROUND: A case-control association study was conducted to investigate a possible involvement of polymorphisms of three renin-angiotensin system genes: ACE (I/D and T-3892C), AGT (M235T and T174M), and AT1R (A1166C) in the early development of hypertension. METHODS: One hundred nineteen hypertensive and 125 normotensive participants aged 18 to 40 years were selected from a broader sample representative of the general population of Croatia. The selection criteria for hypertensive cases were systolic blood pressure (BP) higher than 140 mm Hg or diastolic BP higher than 90 mm Hg and a history of hypertension according to patient interview. RESULTS: Among the polymorphisms investigated, only those located on the ACE gene were associated with hypertension. For ACE I/D, the odds ratio for hypertension of DD versus II homozygote individuals was 2.50 (95% confidence interval [CI] 1.19-5.25) and for ACE T-3892C, the odds ratio of CC versus TT individuals was 2.32 (95% CI 1.05-5.10). Both polymorphisms of the ACE gene were in tight linkage disequilibrium. Of the investigated risk factors for hypertension, only body mass index (BMI) showed an influence on the early development of hypertension, acting independently of the ACE polymorphism. Their additive effect gives rise to 86% of hypertensives in subjects having both the DD genotype and BMI >or=30 kg/m(2). CONCLUSIONS: The present study provides evidence of the association of the ACE gene polymorphisms and premature hypertension. In addition, BMI proved to be another important predictor of the disorder acting independently of the ACE gene.

Plasma concentrations and genetic variation of matrix metalloproteinase 9 and prognosis of patients with cardiovascular disease.

BACKGROUND: Matrix metalloproteinase (MMP)-9 secretion by macrophages and other inflammatory cells accelerates atherosclerotic progression and destabilizes vulnerable plaque in animal models. However, epidemiological data evaluating the prognostic impact of circulating concentrations and functional genetic variations of MMP-9 are lacking. METHODS AND RESULTS: In a prospective study of 1127 patients with documented coronary artery disease, we measured baseline plasma MMP-9 levels and determined the MMP-9/C-1562T and MMP-9/R279Q genotypes. During the follow-up period (mean of 4.1 years), 97 patients died from cardiovascular (CV) causes. Median concentrations of MMP-9 were significantly higher among patients who experienced a fatal CV event than among those who did not (62.2 versus 47.8 ng/mL; P<0.0001). The crude hazard risk ratio of CV death associated with increasing quartiles of MMP-9 was 1.4 (95% CI, 1.2 to 1.8; P<0.0001), and after adjustment for clinical and therapeutic confounders, it was 1.3 (95% CI, 1.1 to 1.6; P=0.005). Additional adjustment for highly sensitive CRP, interleukin-6, fibrinogen, and interleukin-18 revealed a hazard risk ratio to 1.2 (95% CI, 0.9 to 1.6; P=0.15). The T allele of the C-1562T polymorphism was associated with increased MMP-9 levels in a fairly codominant fashion (P=0.004). Although none of the polymorphisms was significantly related with future CV death, there was a significant association (P=0.02) between the R279Q polymorphism and CV events in patients with stable angina. CONCLUSIONS: Plasma MMP-9 concentration was identified as a novel predictor of CV mortality in patients with coronary artery disease. Whether it provides independent prognostic information compared with other inflammatory markers will have to be additionally assessed.

F2-Isoprostane level is associated with the angiotensin II type 1 receptor -153A/G gene polymorphism.

Recent studies have shown that F2-isoprostane levels-a marker for lipid peroxidation-are increased in human renovascular hypertension but not in essential hypertension. Angiotensin II specifically stimulates F2-isoprostane production through activation of the AT1 receptor. The objective was to determine whether there is a relationship between the level of oxidative stress evaluated by measuring urinary F2-isoprostanes levels and polymorphisms of genes involved in the renine angiotensin aldosterone system (RAAS) regulation. The population studied included 100 subjects, 65 of whom were healthy normotensives; the other 35 were suffering from untreated, essential hypertension. The polymorphisms studied concern the genes encoding angiotensin I-converting enzyme (ACE/in16del/ins), angiotensin II receptor type I (AGTR1/A+39C[A+1166C] and AGTR1/A-153G), angiotensinogen (AGT/M235T), and aldosterone synthase (CYP11B2/T344C). Oxidative stress was evaluated by measuring urinary F2-isoprostanes levels. The characteristics of the population were as follows: men/women = 46/56; age = 50 +/- 10 years; BMI = 24 +/- 3 kg/m2; SBP = 131.7 +/- 17.2 mm Hg; DBP = 84.6 +/- 10.4 mm Hg. In univariate analysis, urinary F2-isoprostane levels were significantly lower in the presence of the G allele of AGTR1/A-153G (56 +/- 17 vs 76 +/- 39 pmol/mmol creatinine; P < 0.001, and P < 0.01 after Bonferroni correction for 10 tests). In multivariate analysis, taking into account BP, age, gender, BMI, plasma glucose, and total cholesterol, the G allele of AGTR1/A-153G is linked independently to urinary F2-isoprostanes level (P < 0.01). Our data suggest that F2-isoprostane level depends at least in part on the A-153G polymorphism of the angiotensin II AT1 receptor gene. The clinical and prognostic relevance of this polymorphism requires further investigation.

Common genetic variation of the cholesteryl ester transfer protein gene strongly predicts future cardiovascular death in patients with coronary artery disease.

OBJECTIVES: We sought to evaluate the association between cholesteryl ester transfer protein (CETP) genotypes and the risk of future cardiovascular mortality in patients with coronary artery disease (CAD). BACKGROUND: Polymorphisms of the CETP gene influence CETP activity and high-density lipoprotein (HDL) cholesterol concentration and might affect the long-term prognosis and response to statin therapy in patients with CAD. METHODS: We used serum samples and deoxyribonucleic acid collected at baseline from a prospective cohort of 1,211 patients with CAD prospectively followed up (median follow-up of 4.1 years), 82 of whom experienced a fatal cardiovascular event. The CETP/C-629A and I405V polymorphisms, CETP activity, and HDL cholesterol were determined. RESULTS: Patients carrying the -629A allele had significantly lower CETP activity and higher HDL cholesterol levels. There was a significant association between this polymorphism and the risk of future cardiovascular death. Mortality decreased from 10.8% in CC homozygotes to 4.6% in CA heterozygotes and 4.0% in AA homozygotes (p < 0.0001). This association was independent of potential confounders, particularly HDL cholesterol and CETP activity levels. The clinical benefit of statin therapy was restricted to CC homozygotes, in whom cardiovascular mortality was divided by half (p = 0.01 for treatment x genotype interaction). Similar trends were observed with the CETP/I405V polymorphism, but these effects seemed to be mainly the consequence of linkage disequilibrium with the CETP/C-629A polymorphism. CONCLUSIONS: In patients with CAD, the CETP/-629A allele had a strong protective effect on future mortality from cardiovascular causes, independent of its role on HDL cholesterol and CETP activity levels. Additionally, this common polymorphism appeared to predict which patients with CAD will experience a survival benefit from statin therapy.

A polymorphism in the endothelin-A receptor gene is linked to baroreflex sensitivity.

BACKGROUND: The baroreflex plays an essential role in regulating the cardiovascular system. However, very few studies have focused on the links between genetic polymorphisms and baroreflex sensitivity (BRS). METHODS: A total of 146 hypertensive individuals who had never been treated, and 105 healthy individuals (controls) were included in the study. The genotypes of 17 polymorphisms of 11 genes involved in the regulation of the cardiovascular system were studied. BRS was measured using a sequence method: BRS was evaluated as the slope of spontaneous increases [systolic blood pressure (SBP)+/reflex response (RR)+] or decreases (SBP-/RR-) in SBP and pulse interval by recording blood pressure (BP) continuously for 20 min. RESULTS: Following univariate analysis, the genetic polymorphism of endothelin receptor A EDNRA/C+1222T was found to be significantly correlated with the BRS (SBP-/RR-) level in both populations. In normotensive subjects, mean BRS values (SBP-/RR-) were 11.93 +/- 3.69 ms/mmHg in EDNRA CC homozygotes, 9.94 +/- 2.97 ms/mmHg in CT heterozygotes and 9.51 +/- 3.16 ms/mmHg in TT homozygotes (P = 0.01). In hypertensive subjects, mean BRS values (SBP-/RR-) were 9.26 +/- 3.59 ms/mmHg in EDNRA CC homozygotes, 9.03 +/- 4.14 ms/mmHg in CT heterozygotes and 6.60 +/- 2.42 ms/mmHg in TT homozygotes (P = 0.01). After adjustment for age, sex, SBP and diastolic blood pressure and body mass index, the EDNRA/C+1222T polymorphism remained significantly correlated with BRS in both normotensive (P = 0.01) and hypertensive (P = 0.01) subjects. CONCLUSIONS: These results suggest that the endothelin system may be involved in the regulation of BRS in humans. In particular, the T allele of the EDNRA/C+1222T polymorphism is associated with a reduction in BRS in both healthy and hypertensive subjects.

In-depth haplotype analysis of ABCA1 gene polymorphisms in relation to plasma ApoA1 levels and myocardial infarction.

OBJECTIVE: By regulating the cellular cholesterol efflux from peripheral cells to high-density lipoprotein, the ABCA1 protein is suspected to play a key role in lipid homeostasis and atherosclerosis. Twenty-six polymorphisms of the ABCA1 gene were genotyped and tested for association with plasma levels of ApoA1 and myocardial infarction (MI) in the ECTIM study. METHODS AND RESULTS: In addition to single-locus analysis, a systematic exploration of all possible haplotype effects was performed, with this exploration being performed on a minimal set of "tag" polymorphisms that define the haplotype structure of the gene. Two polymorphisms were associated with plasma levels of ApoA1, 1 in the promoter (C-564T) and 1 in the coding (R1587K) regions, whereas only 1 polymorphism (R219K) was associated with the risk of MI. However, no haplotype effect was detected on ApoA1 variability or on the risk of MI. CONCLUSIONS: ABCA1 gene polymorphisms but not haplotypes are involved in the variability of plasma ApoA1 and the susceptibility to coronary artery disease.

Polymorphism R92Q of the tumour necrosis factor receptor 1 gene is associated with myocardial infarction and carotid intima-media thickness--the ECTIM, AXA, EVA and GENIC Studies.

The TNFRSF1A gene was screened for polymorphisms in 95 subjects with premature myocardial infarction (MI), who also had one parent who had an MI. A total of 10 polymorphisms were found: three in the promoter region, two in exons and five in introns. All polymorphisms were genotyped in ECTIM, a case-control study of MI (1815 subjects). The nonsynonymous 92Q allele was found in 1.8, 1.0 and 1.7% of controls from Strasbourg, Belfast and Glasgow - respectively; in cases: 4.2, 2.2 and 3.2%. The population-adjusted odds ratio (OR) for MI associated with allele Q carrying was 2.15 (95% CI: 1.09-4.23). To check its possible implication in atherosclerosis, this polymorphism was then genotyped in the AXA Study (ultrasound examinations of carotid and femoral arteries in the context of an employment medical examination, 733 subjects), the EVA Study (ultrasound examinations of carotid arteries in a study of cognitive and vascular ageing, 1092 subjects) and the GENIC Study (on brain infarction (BI), 912 subjects). In the AXA Study, among smokers, carrying the 92Q allele was positively associated with the presence of a carotid plaque (OR 5.07; 95% CI: 1.64-15.63) and with a thickening of the carotid intima-media thickness (IMT) (0.59 (0.11) vs 0.54 (0.11), P=0.045). In the EVA Study, carriers of allele 92Q had an increased mean carotid IMT (0.70 (0.09) vs 0.67 (0.13), P=0.02). No significant association of the 92Q allele was found with BI in the GENIC Study. Overall, these results may suggest that carriers of the 92Q allele may be at increased risk of atherosclerosis.

Polymorphisms of genes of the cardiac calcineurin pathway and cardiac hypertrophy.

The study investigated the role of genetic polymorphisms in four genes of the calcineurin pathway on cardiac hypertrophy and dilated cardiomyopathy. The cardiac calcineurin pathway has been suggested to play a role in the development of cardiac hypertrophy in response to a number of physiological and pathological stimuli. Calcineurin, a heterodimeric protein composed of a catalytic and a regulatory subunit, activates the nuclear factor NFATC4 which after translocation to the nucleus associates with the transcription factor GATA4 to activate several cardiac genes involved in hypertrophic response. We have screened the genes encoding the four major components of the heart calcineurin pathway in 95 individuals and identified 27 polymorphisms. These polymorphisms were investigated in 400 selected subjects obtained from a population-based study (LOVE) in relation to echocardiographic parameters. A Gly/Ala substitution at position 160 of the NFATC4 protein (G160A) was associated with left ventricular mass and wall thickness (P=0.02 and 0.006, respectively, GA+AA vs GG), the minor allele (Ala) being associated with lower mean values of these parameters. The other polymorphisms identified by the gene screen were not associated with cardiac phenotypes. For the G160A polymorphism in NFATC4, genotype frequencies were compared between patients with dilated cardiomyopathy and controls obtained from the CARDIGENE Study. Allele A carriers were less frequent in the patient than in the control group (P=0.04). Although the strength of the associations was rather weak, these observations raise the hypothesis that the G160A polymorphism of the NFATC4 gene plays a role in the development of human cardiac hypertrophy.