Search

Background— Several studies have reported that the cholesteryl ester transfer protein (CETP) TaqIB gene polymorphism is associated with HDL cholesterol (HDL-C) levels and the risk of coronary artery disease (CAD), but the results are inconsistent. In addition, an interaction has been implicated between this genetic variant and pravastatin treatment, but this has not been confirmed. Methods and Results— A meta-analysis was performed on individual patient data from 7 large, population-based studies (each >500 individuals) and 3 randomized, placebo-controlled, pravastatin trials. Linear and logistic regression models were used to assess the relation between TaqIB genotype and HDL-C levels and CAD risk. After adjustment for study, age, sex, smoking, body mass index (BMI), diabetes, LDL-C, use of alcohol, and prevalence of CAD, TaqIB genotype exhibited a highly significant association with HDL-C levels, such that B2B2 individuals had 0.11 mmol/L (0.10 to 0.12, P B1B1 individuals. Second, after adjustment for study, sex, age, smoking, BMI, diabetes, systolic blood pressure, LDL-C, and use of alcohol, TaqIB genotype was significantly associated with the risk of CAD (odds ratio=0.78 [0.66 to 0.93]) in B2B2 individuals compared with B1B1 individuals ( P for linearity=0.008). Additional adjustment for HDL-C levels rendered a loss of statistical significance ( P =0.4). Last, no pharmacogenetic interaction between TaqIB genotype and pravastatin treatment could be demonstrated. Conclusions— The CETP TaqIB variant is firmly associated with HDL-C plasma levels and as a result, with the risk of CAD. Importantly, this CETP variant does not influence the response to pravastatin therapy.

This prospective study was designed to evaluate the effect of joint determination of two important contrary biomarkers--homocysteine and glutathione peroxidase (GPx)-1--on cardiovascular risk stratification.Homocysteine plasma levels have been associated with cardiovascular risk. Experimental data suggest that antioxidative GPx-1 activity modulates cardiovascular risk associated with homocysteine.In 643 patients with coronary artery disease, we performed a prospective study to assess the risk of homocysteine plasma levels and GPx-1 activity on long-term cardiovascular risk with a median follow-up of 7.1 years.Both homocysteine and GPx-1 were among the strongest univariate predictors of future cardiovascular risk, even after adjustment for cardiovascular confounders. Homocysteine levels were significantly elevated in individuals with future cardiovascular events (15.4 vs. 13.4 micromol/l; p0.0001); GPx-1 activity was lower (45.3 +/- 13.1 vs. 50.2 +/- 11.0 U/g hemoglobin; p0.0001). In patients with GPx-1 activity below the median value, homocysteine plasma levels above the median were associated with a 3.2-fold (95% confidence interval 1.8 to 5.6; p0.0001) increase in cardiovascular risk, whereas it lost its independent risk prediction in individuals with increased antioxidative capacity, as reflected by high GPx-1 activity. In contrast to single determination, combined assessment revealed a significant increase in the area under the curve of cardiovascular risk predictive models from 0.72, including traditional risk factors to 0.75 and also including homocysteine levels and GPx-1 activity.Plasma homocysteine levels and GPx-1 activity are complementary in identifying individuals at high cardiovascular risk. Joint determination of both biomarkers provides substantial information on top of classic risk factors in cardiovascular risk assessment.

Background Endothelin-1 (ET-1) is a potent vasoactive peptide that has been implicated in the regulation of basal vascular tone. Endothelin-converting enzyme-1 (ECE-1), the main enzyme responsible for ET-1 generation, may contribute to blood pressure (BP) control. A possible association between a polymorphism of the gene encoding ECE-1 (ECE1B C-338A) and BP values in untreated hypertensive women was recently reported. Objective We studied the influence of the ECE1B C-338A polymorphism on BP levels in 1189 subjects participating in the Etude du Vieillissement Arteriel (EVA study), and looked for an interaction between this variant and a polymorphism of the ET-1 gene (EDN1 K198N). Methods The ECE1B C-338A polymorphism was genotyped in 491 men and 698 women; 477 men and 669 women could also be genotyped for the EDN1 K198N polymorphism. Associations between BP levels and genotypes were assessed by ANOVA; ANCOVA was used to control for covariates. Results We found an association between the ECE1B C-338A polymorphism and BP levels in women but not in men. Specifically, females homozygous for the A allele had significantly higher systolic, diastolic and mean BP levels (P = 0.01, 0.02, 0.006 respectively, after adjustment for age and body mass index). Genotyping of the EDN1 K198N polymorphism showed that this variant was not associated with BP values in either men or women, but interacted with the ECE1 variant to influence systolic and mean BP levels in women. Conclusion Results from this large association study suggest that the genes encoding ECE-1 and ET-1 interact to modulate BP levels in women.

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. Conclusion— ABCA1 gene polymorphisms but not haplotypes are involved in the variability of plasma ApoA1 and the susceptibility to coronary artery disease.

Background— Interleukin (IL)-18 promotes atherosclerotic plaque growth and vulnerability. It is unknown, however, whether elevations of circulating IL-18 precede the onset of coronary events in apparently healthy individuals. Methods and Results— We evaluated the relationship between baseline plasma levels of IL-18 and the subsequent incidence of coronary events over a 5-year follow-up in the Prospective Epidemiological Study of Myocardial Infarction (PRIME),which included 10 600 healthy European men aged 50 to 59 years at baseline. Analysis was performed in a nested case-control manner comparing 335 cases with a coronary event to 670 age-matched controls. Baseline levels of IL-18 were significantly higher in men who developed a coronary event than in controls (225.1 versus 203.9 pg/mL, P =0.005). After adjustment for most potential confounders, including C-reactive protein, IL-6, and fibrinogen, the relative risk of future coronary events associated with increasing tertiles of IL-18 was 1.65 (95% CI 1.14 to 2.40, P =0.008) in Northern Ireland, 1.29 (95% CI 0.96 to 1.73, P =0.09) in France, and 1.42 (95% CI 1.13 to 1.79, P =0.003) in both populations combined ( P =0.31 for the test of homogeneity between populations). In all models, IL-18 made an independent contribution to the prediction of risk over lipids or other inflammatory markers such as C-reactive protein, IL-6, or fibrinogen. Conclusions— Plasma IL-18 level was identified as an independent predictor of coronary events in healthy, middle-aged European men. Determination of circulating IL-18 might improve the prediction of coronary events.

The number of infectious pathogens to which an individual has been exposed (pathogen burden) has been linked to the development and the prognosis of coronary artery disease (CAD). The interaction among infection, genetic host susceptibility, and CAD remains unclear. This study was aimed at evaluating the modulation of the association between CAD and pathogen burden, by serum levels of inflammatory markers and polymorphisms of the interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha genes. Immmunoglobulin (Ig) G or IgA antibodies to 8 pathogens were determined in 991 patients with CAD and 333 control subjects. Serum levels of high-sensitivity C-reactive protein, fibrinogen, IL-6, and TNF-alpha were also measured. All subjects were genotyped for the IL-6/G-174C, the TNF/C-851T, and the TNF/G-308A polymorphisms. Analysis of single pathogens demonstrated a positive relation to the presence of CAD for some (Chlamydia pneumoniae, cytomegalovirus, Helicobacter pylori, and herpes virus simplex type 1), but not all pathogens. A strong association between increasing pathogen burden and CAD was confirmed, even after adjustment for risk factors. The prevalence of a high pathogen burden (/=4 pathogens) was 50% in patients and 21% in controls (p0.0001). A high pathogen burden was associated with decreased high-density lipoprotein cholesterol levels (p0.001). The association between CAD and pathogen burden was modulated by the IL6/G-174C polymorphism, the odds ratio being higher in heterozygotes than in both types of homozygotes (p0.05). This interaction appeared to be mediated by variations in serum IL-6 levels. No such interaction was detected with any of the 2 TNF-alpha polymorphisms.

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.

The insertion/deletion ( I/D ) polymorphism of the angiotensin-converting enzyme (ACE) gene might have consequences for the risks of vascular diseases. We examined the ACE genotype and the effects of a perindopril-based blood pressure-lowering regimen on macrovascular events, dementia, and cognitive decline among hypertensive and nonhypertensive patients with a history of cerebrovascular disease. ACE I/D genotypes were measured in 5688 of 6105 individuals with previous stroke or transient ischemic attack who participated in the PROGRESS trial. The DD genotype was significantly ( P

Inflammation underlies both onset and perpetuation of atherosclerosis. Plasma lipoproteins transport the platelet-activating factor-acetylhydrolase (PAF-AH) with potentially anti-inflammatory activities. Our aim was to determine whether PAF-AH activity was associated with inflammatory markers and with coronary artery disease (CAD). PAF-AH activity and a panel of inflammatory mediators were measured in plasma of 496 patients with CAD and in 477 controls; 276 patients presented with stable angina pectoris and 220 with acute coronary syndrome (ACS). Individuals within the highest quartile of PAF-AH activity had an 1.8-fold increase in CAD risk [95% confidence interval (CI), 1.01 to 3.2; P = 0.048] compared with those in the first quartile (adjusted for clinical and metabolic factors). When excluding individuals receiving statin and angiotensin-converting enzyme-inhibitor medication, individuals within the highest quartile of PAF-AH activity revealed a 3.9-fold increase in CAD risk (95% CI, 2.0 to 7.7; P < 0.0001). In these subjects, the plasma PAF-AH activity increased gradually in stable angina and in ACS both in men (P < 0.0001) and in women (P < 0.001), as compared with controls.No correlation was found between PAF-AH levels and those of common markers of inflammation. This study and the previous ones raise the important issue of whether PAF-AH is simply a marker of risk or directly promotes atherosclerosis.

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;PPP=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.

Background — Depression is a risk factor for myocardial infarction (MI). Selective serotonin reuptake inhibitors reduce this risk. The site of action is the serotonin transporter (SLC6A4), which is expressed in brain and blood cells. A functional polymorphism in the promoter region of the SLC6A4 gene has been described. This polymorphism may be associated with the risk of MI. Methods and Results — The SLC6A4 polymorphism has been investigated by polymerase chain reaction in 671 male patients with MI and in 688 controls from the Etude Cas-Témoins de l’Infarctus du Myocarde (ECTIM) multicentric study. Percentages for LL, LS, and SS genotypes were 35.5%, 45.4%, and 19.1%, respectively, for cases versus 28.1%, 49.1%, and 22.8%, respectively, for controls. S allele frequency was 41.8% and 47.4% for cases and controls, respectively. After adjustment for age and center by using multivariable logistic regression, the odds ratio for MI associated with the LL genotype was 1.40 (95% CI 1.11 to 1.76, P =0.0047). Conclusions — The LL genotype of the SLC6A4 polymorphism is associated with a higher risk of MI. This could be attributable to the effect of the polymorphism on serotonin-mediated platelet activation or smooth muscle cell proliferation or on other risk factors, such as depression or response to stress.

Linkage disequilibrium (LD) is the central concept of genetic association studies. Although LD has been shown not to be uniformly distributed across the genome, limited information is available about the characteristics of LD within candidate genes at large. We screened coding and regulatory regions of 50 candidate genes for cardiovascular diseases and identified 228 polymorphisms. The overall sequence diversity was 3.81 +/- 0.31 x 10(-4). Intragenic LD was generally very strong, with 40% of the 464 pairs of polymorphisms exhibiting a complete LD. However, if we consider /D'/ = 0.7 as an arbitrary limit for useful LD in association studies, 26% of the pairs fell below this threshold, half of which being in negative LD, a situation where LD is even more difficult to detect. Non-synonymous coding polymorphisms, which are more likely to have a functional role, were more represented among low-frequency alleles and were more often in complete negative LD with other polymorphisms. This implies that in many situations the power to detect the effect of a non-synonymous polymorphism by measuring a nearby marker might be low. Although intragenic LD was partly a function of physical distance, gene-specific patterns of LD were observed, making it difficult to provide general guidelines for selecting the most useful polymorphisms in association studies. For all these reasons, association studies should concentrate on the overall sequence variation of functionally important regions of candidate genes and not only on a few polymorphisms. The variability of important intergenic regions identified by different approaches including comparative genomics will also have to be assessed.

Objectives The β 2 -adrenoceptor (ADRB2) plays a pivotal role in signalling in relation to hypertension and obesity. Polymorphisms of the ADRB2 gene have been shown to be potentially related to essential hypertension and other non-cardiovascular disease phenotypes. We investigated whether genetic variation of the ADRB2 gene might be related to essential hypertension or myocardial infarction (MI). Methods Four ADRB2 gene polymorphisms C19R (T-47C), T-20C, G16R (G+46A), Q27E (C+79G) were investigated in two studies: PEGASE, a study of moderate to severe hypertension (707 cases) conducted in France, and ECTIM, a case-control study of Ml (1178 cases, 1187 controls) conducted in France, Northern Ireland and Scotland. Genotyping was performed using allele-specific oligonucleotides. Results The ADRB2 polymorphisms T-20C and Q27E were found to be completely concordant, generating the haplotypes [T -20 -Q 27 ] and [C -20 -E 27 ]. Three main haplotypes accounted for 94% of all haplotypes: [R 19 -G 16 -E 27 ] (39%), [C 19 -R 16 -Q 27 ] (35%) and [C 19 -G 16 -Q 27 ] (20%). Haplotype frequencies were not significantly different between countries. Allele and genotype frequencies did not differ significantly between cases with essential hypertension or Ml and control subjects. There was no association of the polymorphisms with early onset hypertension, blood pressure level, coronary artery stenosis or any other phenotype measured in these study populations. In the ECTIM Study, our calculation revealed that we could have detected an odds ratio (OR) for Ml of 1.3 with 80% power at a 5% type I error probability, the corresponding value for the PEGASE Study being an OR of 1.6 for hypertension. Conclusions From our present analysis we conclude that the ADRB2 gene polymorphisms studied do not contribute in any important way to the risk of essential hypertension or Ml in subjects of European ancestry.

Increased levels of physical activity may improve the lipid profile, but is this effect identical across apolipoprotein E ( apoE ) genotypes? A population-based cross-sectional survey conducted from 1999 to 2000 included 1708 randomly selected men and women aged 35 to 74 years. A validated physical activity questionnaire measured, for each participant, the total energy expenditure and its percentage used in high-intensity activities (%high-intensity activity), eg, brisk walking and sports. The effects of the apoE× %high-intensity activity interaction on the lipid profile were investigated by using multiple linear regression models. Among men, increased %high-intensity activity had greater protective effects in the apoE4 group regarding (1) high density lipoprotein (HDL) cholesterol ( P apoE2 (interaction P =0.05) or apoE3 (interaction P P apoE3 group (interaction P =0.07). A 10% increase of %high-intensity activity by an apoE4 man would correspond with a 0.07-mmol/L increase in HDL cholesterol and a −0.15-mmol/L decrease in triglycerides. Among women, only the protective effects of physical activity on HDL cholesterol in the apoE4 group versus the apoE2 group was statistically significant. Spending a larger fraction of the total energy expenditure in high-intensity activities may counteract the atherogenic effects of the ε 4 allele on the lipid profile.

OBJECTIVE--To assess the reliability of reported family histories of myocardial infarction. DESIGN--A case-control study in which reported histories of first degree relatives were validated from death certificates, general practitioners' records, and hospital notes. SETTING--Participants enrolled in the Belfast centre of the World Health Organisation's study monitoring trends and determinants in cardiovascular disease (MONICA). SUBJECTS--200 men who survived myocardial infarction and 200 age matched controls drawn randomly from the population. MAIN OUTCOME MEASURES--The sensitivity, specificity, positive predictive value, and proportion of overall agreement with validated records of reported family histories of myocardial infarction in first degree relatives; odds ratios for myocardial infarction, given at least one reported relative or at least one verified relative being affected. RESULTS--349 of the 400 probands provided detailed family histories, reporting on 2812 first degree relatives. The overall sensitivity, specificity, and positive predictive value of reported histories were 67.3%, 96.5%, and 70.5% for cases and 68.5%, 97.7%, and 73.8% for controls. The kappa coefficients were modest: 0.65 for cases and 0.68 for controls. The odds ratios for myocardial infarction, given at least one affected relative, were not substantially inflated by recall bias. Some recall bias was evident for the probands' reports of their siblings' histories of myocardial infarction, the odds ratio for a reported history being 1.67 (95% confidence interval 1.09 to 2.57) and for the validated history 1.54 (1.01 to 2.37). CONCLUSIONS--Although the relative risk of disease is correctly estimated, the predictive accuracy of a casual family history of myocardial infarction may limit the effectiveness of targeted screening programmes. They may, however, complement other strategies based on genetic testing.

Cathepsin G (CTSG), a serine protease released from activated neutrophils, may cause platelet activation, leading to intravascular thrombosis, thus contributing to cardiovascular and cerebrovascular disease. Applying the candidate gene approach, we screened the 5′-flanking region and the entire coding region of the CTSG gene for genetic variation by using polymerase chain reaction/single-strand conformation polymorphism analysis from 96 patients at high risk for myocardial infarction (MI). We identified 4 polymorphisms in the 5′-flanking region (G-618C, G-315A, C-179T, and C-160T) and 1 polymorphism in the coding region (Asn125Ser) of the gene and genotyped the participants in the Etude Cas-Temoins sur l’Infarctus du Myocarde (ECTIM Study), a case-control study for MI, and in the Étude du Profil Génétique de l’Infarctus Cérébral (GENIC Study), a case-control study for brain infarction (BI), for all identified genetic variants. The potential in vitro functionality of the 4 variants in the 5′-flanking region was investigated with transient transfection analyses in U937 cells with different allelic promoter constructs by using a luciferase assay. Our in vitro analyses did not reveal any differences for the investigated allelic constructs with respect to promoter activity, and none of the polymorphisms in the 5′-flanking region was associated with the available phenotypes in either study. Allele and genotype distributions of all identified polymorphisms did not globally differ between cases and controls in the ECTIM Study. However, in patients from the ECTIM Study, the Ser125 allele was significantly associated with elevated plasma fibrinogen levels ( P =0.006), but this effect was not seen in controls (case-control heterogeneity, P =0.04). There was a significant interaction between CTSG Asn125Ser and the β-fibrinogen gene polymorphism G-455A on plasma fibrinogen levels ( P =0.04). In the GENIC Study, the odds ratio for BI associated with CTSG Ser125 carrying was 1.82 (95% CI 1.16 to 2.84, P =0.008) in patients without a history of cardiovascular or cerebrovascular diseases. Our results indicate that the CTSG Ser125 allele is associated with plasma fibrinogen levels in MI patients from the ECTIM Study and with BI in the GENIC Study. Further studies should be carried out to define the underlying mechanisms.

Degenerate oligonucleotide primed amplification (DOP-PCR) is an efficient method for performing whole genome amplification. We analysed the yield of DNA using this technique starting with various quantities of material. We used DOP-PCR products to genotype single nucleotide polymorphisms and insertion/deletion polymorphisms. DOP-PCR also proved usable for SSCP analysis.

Arterial stiffness is associated with excess morbidity and mortality, independently of other cardiovascular risk factors. Age is the main determinant responsible for arterial wall changes leading to arterial stiffening. Environmental and genetic factors may however influence the magnitude of the effects of age on large artery stiffness.The present study assessed whether or not the relationship between age and aortic stiffness was influenced by genetic variants of angiotensinogen (AGT 174T/M, 235M/T), angiotensin converting enzyme (ACE I/D), angiotensin II type 1 receptor (AT1 1166A/C, -153A/G) and aldosterone synthase (CYP11B2 -344T/C). This study was realized in 441 untreated hypertensive subjects of European origin (aged 18-74 years). Aortic stiffness was assessed by carotid-femoral pulse wave velocity (PWV).Carriers of the angiotensin II type 1 receptor -153G allele showed a steeper age/PWV relationship than the AT1 -153AA subjects. The effect of the AT1 -153A/G polymorphism on aortic stiffness became apparent after the age of 55 years. In subjects with the AT1 1166C allele, the relationship age/PWV is shifted upward, indicating higher values of aortic stiffness at any age compared to the AT1 1166AA patients. Carriers of both the AT1 1166C and -153G alleles presented the additive effects of these 2 genotypes on aortic stiffness. Angiotensinogen, ACE and CYP11B2 genotypes did not influence the effects of age on PWV.AT1 receptor genotypes could influence arterial ageing in hypertensive subjects. These results also show that the association between genotypes and arterial stiffness may manifest itself later in life.

To the Editor: Roest et al1 reported a nested case-control study that assessed the relation between 4G/5G polymorphism in the plasminogen activator inhibitor (PAI-1) gene and cardiovascular and cerebrovascular mortality in women. The authors found that 4G/4G homozygotes had a decreased risk of dying from stroke compared with 5G/5G homozygotes (relative risk, 0.4; 95% confidence interval [CI], 0.2 to 0.7); the relative risk was 0.7 (95% CI, 0.4 to 1.1) for 4G/5G heterozygotes. The authors raised 2 important issues. First, because the diagnosis was not always confirmed by CT scan or MRI, they could not distinguish brain infarcts (BIs) from hemorrhages, which are very different from a pathophysiological perspective. Thus, the possibility that misclassification may have introduced some bias cannot be discarded. The authors think that this is unlikely because the incidence of brain hemorrhages was lower than that of BIs; however, it is also true that the case fatality of hemorrhages was higher than that of BIs. …

Platelet-derived growth factors (PDGFs) may play an important role in the development of atherosclerosis acting as chemoattractants and mitogens for vascular smooth muscle cells and macrophages. Three dimeric forms of PDGF (AA, AB, BB) have different activities due to distinct binding properties mediated by two types of PDGF receptors (Ralpha, Rbeta). To investigate the possible contribution of molecular variants in the human PDGF-A and PDGF-Ralpha genes to coronary heart disease we screened these genes for polymorphisms by polymerase chain reaction/single-strand conformation polymorphism analysis. A total of 600 men with myocardial infarction and 717 age-matched male controls from four populations in Northern Ireland and France (the ECTIM Study) were gneotyped for newly identified polymorphisms in the genes encoding PDGF-A (C-26IN3T, H69H, C+12IN5T) and PDGF-Ralpha [-1630 I/D (+/-AACTT), A-1506G, C-1390G, G-956A, C-908A, G-793T, +69 I/D (+/-GA)] using allele-specific oligonucleotides. All PDGF-Ralpha polymorphisms, except C-908A, involving a nucleotide change in a common consensus site for GCF and SP-1 transcription factors, were in nearly complete association, generating two major haplotypes. The PDGF-A and PDGF-Ralpha polymorphisms provided a heterozygosity of 0.69 and 0.40, respectively. Genotype and allele frequencies of the PDGF-A and PDGF-Ralpha polymorphisms did not differ between patients with myocardial infarction and controls in either country. None of the polymorphisms investigated was associated with blood pressure, coronary artery stenosis, or any biochemical parameter available in the ECTIM Study.

Background : Although the majority of evidence does not support association between Helicobacter pylori infection and ischaemic heart disease, the nature of this relationship may differ when virulence of the infecting strains are examined. Methods and results : The prevalence of IgG antibody evidence of infection with CagA positive stains of H. pylori was investigated in stored plasma samples from 259 cases of myocardial infarction (aged 25–70 years, 74 males) and 259 population based controls from the same area in Northern Ireland. Two-hundred and seventy (52.1%) subjects were seropositive for anti-CagA IgG. CagA seropositivity was more common in cases than in controls: 56.4 vs 47.9%, odds ratio for seropositivity in cases (95% CI) 1.41 (1.00, 1.99). Substantial attenuation of this relationship occurred on adjustment for age, sex, number of siblings, smoking and measures of socio-economic status: odds ratio (95% CI) 1.16 (0.79, 1.70). A similar pattern was seen for seropositivity for all H. pylori strains. Conclusion : Infection with the more virulent strains of H. pylori , as with all strains, is not associated with myocardial infarction.

Apolipoprotein E (APOE) is a major protein in lipid metabolism existing in three common isoforms: APOE2, -3 and -4. The varepsilon4 allele of the APOE gene ( APOE ) coding for the APOE4 isoform is associated with an increased risk of myocardial infarction (MI) and of Alzheimer's disease (AD). Recently, several polymorphisms in the APOE regulatory region have been reported. Some of these have been associated with AD and modified APOE allelic mRNA expression in AD brains. Here, we have investigated whether three of these promoter polymorphisms (-491AT, -427CT and -219GT) can also modify cardiovascular risk. The hypothesis was tested in a large multicentre case-control study of MI, the ECTIM Study, on 567 cases and 678 controls. Among the three APOE promoter polymorphisms tested, only the-219T allele was associated with a significantly increased risk of MI (OR = 1.29, 95% CI: 1.09-1.52, P0.003) and the effect was shown to be independent of the presence of the other mutations, including the APOE epsilon2/epsilon3/epsilon4 polymorphism. Moreover, the-219T allele greatly decreased the APOE plasma concentrations in a dose-dependent manner ( P0.008). These data indicate that the-219GT polymorphism of the APOE regulatory region emerges as a new genetic susceptibility risk factor for MI and constitutes another common risk factor for both neurodegenerative and cardiovascular diseases.

Endothelin-1 is a potent vasoconstrictor that has also mitogenic properties, stimulating the synthesis and secretion of several vasoactive molecules. There is much evidence to suggest that endothelin-1 might be involved in the pathogenesis of hypertension, atherosclerosis, and ischemic heart disease. Endothelin-1 exerts its effects through at least two receptors, ET(A) and ET(B), which are encoded by different genes and have separate tissue distributions and biologic properties. The objective of this study was to identify polymorphisms of the ET(A) and ET(B) receptor genes and to study their association with myocardial infarction (MI) and blood pressure. The coding regions and 1.3 kb upstream of the ET(A) and ET(B) receptor genes were explored by polymerase chain reaction/single strand conformation polymorphism. Six polymorphisms were found in the ET(A) receptor gene and three in the ET(B) receptor gene. Most of these polymorphisms were frequent. Associations between the detected polymorphisms, blood pressure, and MI were examined in the ECTIM study, a multicenter study comparing 652 patients having survived an MI and 773 controls from Belfast (Northern Ireland) and France. Alleles at the different polymorphic sites were similarly distributed in patients with MI and controls. Allele frequencies were similar in both countries, except for the ET(A)/-231 G allele, which appeared more frequently in France than in Belfast (P < .01). The mean systolic and diastolic blood pressure levels did not significantly differ between genotypes. However, a C/T substitution located in the nontranslated part of exon 8 of the ET(A) receptor gene (ET(A)/EX8nt1363) was associated with pulse pressure (P < .005). These results do not support an involvement of the endothelin receptor genes in a predisposition to MI or the determination of blood pressure levels, but suggest that a polymorphism of the ET(A) receptor gene might influence the pulse pressure. This result will have to be confirmed in other studies.

Background —Gelatinase B , a matrix metalloproteinase that has proteolytic activity against connective tissue proteins, has been suggested to be important in the connective tissue remodeling processes associated with atherogenesis and plaque rupture. This study tested the hypothesis that sequence variation in the promoter region of the gelatinase B gene influences its expression, predisposing individuals carrying certain genetic variants to more severe atherosclerosis. Methods and Results —Single-strand conformation polymorphism analysis was carried out to search the promoter region of the gene encoding gelatinase B for naturally occurring genetic variation. As a result, an unreported common polymorphism was detected, which arose from a cytosine (C) to thymidine (T) transition at position −1562 relative to the start of transcription. Transient transfection experiments and DNA-protein interaction assays indicated that the T allele had a higher promoter activity than the C allele, which appeared to be due to preferential binding of a putative transcription repressor protein to the C allelic promoter. A sample of 584 male patients with myocardial infarction and 645 age-matched male healthy control subjects were genotyped. The allele frequencies were not significantly different between the cases and control subjects. However, in 374 patients with available angiographic data, 26% of those carrying 1 or 2 copies of the T allele had >50% stenosis in 3 coronary arteries, whereas only 15% of C/C homozygotes had triple-vessel disease. Conclusions —These data suggest that this functional genetic variation influences gelatinase B gene promoter activity in an allele-specific manner and has an effect on atherosclerotic phenotype.

The renin-angiotensin-aldosterone system plays an important role in large artery structure and blood pressure homeostasis. Among the genes coding for different components of this system, the aldosterone synthase (CYP11B2) gene could play an important role, but has been less investigated. We examined the role of two variations of the aldosterone synthase gene (CYP11B2), one located in the promoter of the gene, T 344 C, the other in the 7th exon, the T 4986 C (Val/Ala), on plasma levels of renin and aldosterone, blood pressure, and arterial stiffness in subjects with essential hypertension. Subjects of European origin (n = 216) were examined during a 1-day hospitalization. Treatment, if any, was interrupted for at least 21 days before. Arterial stiffness was evaluated by measuring pulse wave velocity. Renin and aldosterone levels were evaluated by using a radioimmunoassay. The two polymorphisms were in complete linkage disequilibrium, as suggested by the presence of only three haplotypes in this population (T -344 T 4986 , T -344 C 4986 and C -344 T 4986 ) The mean age and blood pressure values were similar in the different genotypes. Presence of the -344 C allele was associated with elevated levels of plasma aldosterone: 90 ± 8 pg/mL for TT (n = 67), 110 ± 6 pg/mL for TC (n = 107), and 129 ± 10 pg/ mL for CC (n = 42) (test of codominant effect, P < .002 after adjustment for age and 24-h Na + urine excretion). Pulse wave velocity was also increased in the -344 C allele carriers: 11.3 ± 0.4 m/sec, 12.7 ± 0.3 m/sec, 12.0 ± 0.5 m/sec in the TT, TC, and CC genotypes, respectively. No association was found between the T 4986 C polymorphism and the studied variables. In patients with essential hypertension, a variant on the promoter region of the aldosterone synthase gene is associated with significant differences in plasma aldosterone levels and arterial stiffness. These differences are not associated with variations in blood pressure levels.

P-selectin is an adhesion molecule, expressed at the surface of activated cells, that mediates the interaction of activated endothelial cells or platelets with leukocytes. P-selectin expression is increased in atherosclerotic plaques, and high plasma levels of this molecule have been observed in patients with unstable angina. We investigated the P-selectin gene as a possible candidate for myocardial infarction (MI). The P-selectin gene is situated on chromosome 1q21-q24, spans >50 kb and contains 17 exons. The sequences of the 5'-flanking region and exons of 40 alleles from patients with MI were screened for polymorphisms using polymerase chain reaction/single-strand conformation polymorphism (PCR-SSCP) and sequencing. Thirteen polymorphisms were identified: five in the 5'-flanking and eight in the exonic sequences. Four polymorphisms (Ser290Asn, Asn562Asp, Leu599Val and Thr715Pro) predicted a change in the amino acid sequence of the P-selectin protein. All P-selectin polymorphisms as well as a common E-selectin polymorphism, Ser128Arg which has been reported as being associated with an increased risk of premature coronary heart disease (CHD), and is in tight linkage disequilibrium with several P-selectin polymorphisms, were investigated in 647 patients with MI and 758 control subjects from four regions of France and Northern Ireland (the ECTIM study). The entire set of P-selectin polymorphisms provided a heterozygosity of 91%. The polymorphisms were tightly associated with one another and displayed patterns of linkage disequilibrium suggesting the existence of highly conserved ancestral haplotypes. The five polymorphisms in the 5'-flanking region of the gene were unrelated to MI or any relevant phenotype measured in the ECTIM study. We inferred that the four missense variants identified in the coding region predicted eight common forms of the P-selectin protein. The Pro715 allele which characterizes one of these forms was less frequent in France than in Northern Ireland ( P < 0.002) and in cases than in controls ( P < 0.002; P < 0.02 after correction for the number of tests). We conclude that the P-selectin gene is highly polymorphic and hypothesize that the Pro715 variant may be protective for MI. Whether this variant affects the properties of the P-selectin protein in a way which is compatible with this hypothesis needs to be checked experimentally.

Genetic studies may help us to understand the mechanisms underlying the involvement of various neuro-humoral factors in the regulation of the mechanical properties of large arteries. We have shown previously that the angiotensin II type 1 receptor gene polymorphism was a strong determinant of aortic stiffness in hypertensives.To assess the contribution of two polymorphisms of the endothelial nitric oxide synthase gene to aortic stiffness in normotensive and hypertensive subjects in the same cohort.We studied 309 untreated hypertensive and 123 normotensive subjects. Aortic stiffness was evaluated by measuring the carotid-femoral pulse-wave velocity non-invasively. The endothelial nitric oxide synthase gene polymorphisms G10-T at intron 23 (GIN23T) and G298-T at exon 7 (Glu298Asp) were determined in each subject.The distributions of genotypes and allele prevalences of the endothelial nitric-oxide synthase G10-T polymorphisms among hypertensive and normotensive subjects were similar. In contrast, the prevalence of the nitric oxide synthase 298G allele was higher in the hypertensive group than it was among normotensive subjects. We found no association of the endothelial nitric oxide synthase genotypes with blood pressure levels or pulse-wave velocity for either population.The present results do not suggest that two common polymorphisms of the endothelial nitric oxide synthase gene are involved in the regulation of aortic stiffness in hypertensive and normotensive individuals. The higher prevalence of endothelial nitric oxide synthase 298G allele among hypertensives suggests that this gene is involved in essential hypertension but this observation needs further confirmation.

In their recent paper in Clinical Chemistry , Bosma et al. (1) were unable to demonstrate a protective effect of the UGT1A1*28 allele against coronary heart disease (CHD). This was surprising because individuals homozygous for the UGT1A1*28 allele have higher serum bilirubin than do heterozygous or homozygous wild-type individuals and serum bilirubin concentration is inversely related to risk of CHD(2)(3). We studied UGT1A1 bilirubin uridine diphosphate glucuronosyl transferase genotypes in the ECTIM case-control study of myocardial infarction (MI) (4). The study was conducted on a predefined subsample of the ECTIM Study population. DNA was available for 366 male cases and 314 male controls [from Strasbourg and Toulouse: 181 cases with mean (SD) age 53.7 (8.0) years and 159 controls, with mean (SD) age 52.7 (8.7) years; from Northern Ireland: 185 cases with mean (SD) age 54.8 (8.0), and 155 controls, with mean …

Abstract The biological role of the very low density lipoprotein receptor (VLDL-R) in humans is not yet elucidated. This cellular receptor binds apolipoprotein E (apoE)-containing lipoparticles and is mainly expressed in peripheral tissues. The VLDL-R gene contains a polymorphic triplet (CGG) repeat located 19 bp upstream of the initiation codon. We explored the allelic distribution of this repeat in 1384 subjects of European Caucasian origin, 609 of them surviving a myocardial infarction. Six alleles corresponding to 5, 6, 7, 8, 9, and 11 repeats were detected in this population. The alleles 5, 8, and 9 were the most frequent, with frequencies of 0.413, 0.275, and 0.292, respectively. No association was found between the VLDL-R polymorphism and myocardial infarction. In controls without lipid lowering treatment, a statistically significant interaction between VLDL-R genotype and apoE phenotype was found for plasma triglycerides ( P VLDL-R polymorphism on LpE:B and LpA-I. The VLDL-R 9 allele was associated with lower levels of plasma LpE:B ( P P VLDL-R has a modest influence on circulating lipoproteins in humans.

Apolipoprotein E (apo E) is a component of all the classes of lipoproteins and can be distributed among apo B- (LpB) and non apo B-containing lipoproteins (Lp-non-B). Using a new electroimmunoassay kit, plasma apo E, apo E in Lp-non-B (apo E-Lp-non-B) and apo E in LpB (apo E-LpB) levels were measured in healthy control subjects (n=481) from 3 centers participating in the ECTIM study (Etude Cas-Témoins sur l'Infarctus du Myocarde), a population-based study on myocardial infarction. The distribution of apo E among lipoproteins was analyzed according to the apo E phenotype after adjustment for center, body mass index, tobacco use, alcohol consumption and triglycerides. Apo E was higher (average excess: + 0.32; P0.0001) and lower (average excess: -0.12; P0.0001) in subjects carrying the allele epsilon2 and the allele epsilon4 respectively, than in apo E3/3 subjects. These differences are the consequence of variations in apo E-Lp-non-B which clearly differed between the groups classified according to their apo E phenotype (P0.0001). The average excess of apo E Lp non-B compared to apo E3/3 subjects was + 0.43 (P0.0001) and -0.22 (P0.0001) for the epsilon2 and epsilon4 alleles respectively. Apo E-LpB was lower in subjects carrying the epsilon2 allele (P0.02) while the presence of the epsilon4 allele did not modify this parameter. The proportion of apo E within HDL was clearly higher and lower in subjects carrying apo E2 and apo E4 respectively than in apo E3/3 subjects. Although triglyceride levels were dependent on the apo E phenotype, the adjustment of the proportion of apo E in HDL for triglycerides hardly modified the results. For the first time, these results, using direct measurements on a large number of subjects, confirm the greater preference of apo E4 over apo E2 for LpB and vice versa for Lp-non-B. They also show a greater affinity of apo E2 for HDL compared to apo E3. This high affinity of apo E2 for HDL could be due to the formation of the apo E-A-II complex. These results indicate that apo E phenotype modulates the distribution of apo E among lipoproteins and suggest differences in lipoprotein metabolism between apo E2, apo E3 and apo E4.

Angiotensin-converting enzyme inhibitors improve arterial stiffness independently of blood pressure reduction. Since we have recently shown that in hypertensive individuals the A 1166 C polymorphism of the angiotensin II type 1 receptor (AT 1 -R) is an independent determinant of aortic stiffness, we designed the present study to assess the influence of this polymorphism on the changes of aortic stiffness after chronic treatment with the angiotensin-converting enzyme inhibitor perindopril and the calcium channel blocker nitrendipine. Forty perindopril- and 42 nitrendipine-treated hypertensive individuals were studied. We evaluated aortic stiffness by measuring the carotid-femoral pulse wave velocity. Carriers of the AT 1 -R C allele showed higher baseline values of pulse wave velocity than AA homozygotes ( P P 1 -R C carriers (−1.38±0.35 versus +0.04±0.60 m/s, respectively; P 1 -R A 1166 C genotype, an angiotensin-converting enzyme inhibitor and a calcium channel blocker affect pulse wave velocity in opposite ways. Since some evidence shows that increased pulse wave velocity may enhance cardiovascular risk, it might be useful for physicians to consider the AT 1 -R genotype when prescribing an angiotensin-converting enzyme inhibitor or calcium channel blocker to a hypertensive individual.

Transforming growth factor-β1 (TGF-β1) plays an important role in the modulation of cellular growth and differentiation and the production and degradation of the extracellular matrix. A number of experimental results suggest that TGF-β1 may be involved in cardiovascular physiopathology. In the present study, we assessed whether the TGF-β1 gene is a candidate gene for coronary heart disease or hypertension. We screened the coding region and 2181 bp upstream of the TGF-β gene for polymorphisms and identified seven polymorphisms: 3 in the upstream region of the gene at positions −988, −800, and −509 from the first transcribed nucleotide; 1 in a nontranslated region at position +72; 2 in the signal peptide sequence Leu 10 →Pro, Arg 25 →Pro; and 1 in the region of the gene coding for the precursor part of the protein not present in the active form, Thr 263 →Ile. We analyzed these TGF-β1 polymorphisms in 563 patients with myocardial infarction and 629 control subjects from four regions in Northern Ireland and France. The Pro 25 allele was more frequent in patients than in control subjects in Belfast ( P P 25 allele was associated with a lower systolic pressure in the four control groups ( P 25 than in homozygotes for Arg 25 (odds ratio, 0.43; 95% confidence interval, 0.19 to 0.92; P 25 allele was associated with an increased risk of myocardial infarction and a reduced risk of hypertension, we favor a cautious interpretation of these apparently inconsistent results. Other studies will need to verify whether these associations are real.

Paraoxonase is a high-density-lipoprotein associated enzyme capable of hydrolyzing lipid peroxides, which has been suggested to contribute to atherosclerosis and coronary heart disease (CHD). We studied the Gln/Arg polymorphism affecting codon 192 of human paraoxonase (PON 192) to determine whether this polymorphism, which is associated with serum paraoxonase (PON) activity, represents a risk factor for myocardial infarction (MI). The PON 192 polymorphism was analysed in 642 male patients with myocardial infarction and 701 age-matched controls participating in the ECTIM Study (Etude Cas-Temoins de l'Infarctus du Myocarde). The frequency of the Gln allele was 0.69 in cases and 0.70 in controls (ns). The frequency of the PON 192/Arg allele in 405 MI patients who underwent coronary angiography was 0.295, 0.323 and 0.331, respectively in those with 1, 2 or 3 stenosed arteries (stenosis > 50%) (ns). The mean levels of several plasma lipids, lipoproteins and apolipoproteins were compared between the 3 PON genotypes and no difference was observed. The PON 192 polymorphism was unrelated to MI, the severity of coronary atherosclerosis and to plasma levels of several lipid variables.

The genetic factors associated with a predisposition to acute coronary syndromes such as myocardial infarction (MI) and sudden death may act through chronic processes, mainly atherosclerosis, hypertension, vascular and cardiac hypertrophy and endothelial dysfunction; or acutely, by promoting plaque rupture, thrombosis or vasoconstriction. These pathological manifestations are tightly interconnected. Chronic processes modify the probability of the occurrence of acute manifestations and, conversely, plaque rupture and thrombosis may contribute to accelerated evolution of the atheromatous plaque. The interplay of these different factors may affect the risk of an individual developing an acute coronary event in response to a triggering factor.

The internal structure of different alleles of the minisatellite present at the 3' end of the apolipoprotein B (ApoB) gene has been analysed by different approaches including sequencing. The repeat unit arrangements of the minisatellite on 570 chromosomes belonging to European and African populations were thus determined. It was possible to group the alleles using this structural criterion much more clearly than by the number of repeat units which can in some cases be misleading in case-control genetic epidemiological studies using such DNA sequences as markers. We were thus able to define five types (a to e) of alleles and their subtypes and to recognize clearly those which are, respectively, specific of the African and Caucasian populations. A phylogeny of the different alleles found in all human populations could also be deduced by this approach. The different putative mutational events leading from one type, or subtype, to the other were simply determined as point mutations, expansion/contraction and conversion events. Sequencing of one chimpanzee's allele suggested that the ApoB minisatellite was present before divergence between great apes and humans. It was determined also that a particular ApoB gene haplotype was in linkage disequilibrium with the minisatellite (a) type of alleles. This and the observation that the potential scaffold attachment regions (SAR) and topoisomerase II binding sites present in this minisatellite have a different distribution between the Caucasian and the African specific alleles suggest that the minisatellite could be involved in the epidemiology of coronary diseases.

Along with superoxide dismutase, glutathione peroxidase 1 is one of the cellular antioxidant enzymes that have a key role in controlling reactive oxygen species. It uses glutathione to reduce hydrogen peroxide to water and lipid peroxides to their respective alcohols. There are suggestions from in vitro and animal studies that these enzymes could protect against atherosclerosis. This prospective study examined the possibility that relatively high activity of antioxidant enzymes protects against cardiovascular events. The study population included 636 patients suspected of having coronary artery disease who were followed for a median period of 4.7 years. Stable angina was present in 510 patients and symptoms of unstable angina in 133. Coronary angiography disclosed coronary artery disease with more than 30% stenosis of at least 1 major coronary artery in 558 patients. Enzyme activities were measured in washed red blood cells. Baseline levels of glutathione peroxidase 1 activity were significantly lower in patients who died of cardiac causes or had a nonfatal myocardial infarction than in those not having either of these events. The relationship persisted when patients who died and those with nonfatal events were separately analyzed. Rates of cardiovascular events increased across decreasing quartiles of baseline enzyme activity; patients in the lowest quartile had approximately 3 times more events than those in the highest quartile. Enzyme activity was lower in current smokers than in those who had never smoked. Except for statins, which were associated with higher glutathione peroxidase 1 activity, there was no apparent association between cardiovascular medications and the activity of either glutathione peroxidase 1 or superoxide dismutase. The inverse relationship between glutathione peroxidase 1 activity and the relative risk of coronary disease events was changed very little after adjusting for cardiovascular risk factors and clinical features. Patients with the highest glutathione peroxidase 1 activity had a hazard ratio of 0.29 (95% confidence interval, 0.14-0.60) compared with those in the lowest quartile. These findings indicate that in patients with coronary artery disease, red blood cell levels of glutathione peroxidase 1 activity are inversely associated with the risk of future cardiovascular events, both fatal and nonfatal. Estimating enzyme activity might prove helpful for identifying patients who would benefit from prophylactic antioxidant treatment.

To study the association between polymorphisms of the angiotensinogen (AGT) gene and blood pressure in population-based samples, and to determine whether genetic variation at the AGT locus is involved in the susceptibility to myocardial infarction.The study population comprised 630 cases who survived a myocardial infarction, recruited from the World Health Organization Monitoring Cardiovascular Diseases registers in Belfast, Lille, Strasbourg and Toulouse, and 741 controls drawn from the corresponding populations. The AGT polymorphisms investigated were T174M and M235T. High blood pressure was defined as diastolic blood pressure100 mmHg or the use of antihypertensive medication, or both.In the controls the mean +/- SEM frequency of the M174 allele was 0.116 +/- 0.008, and that of the T235 allele was 0.401 +/- 0.013. In the whole population blood pressure levels and prevalence of high blood pressure did not vary according to T174M and M235T genotypes. However, obesity appeared as a crucial factor influencing the relationship between high blood pressure and T174M. In subjects with body mass index26 kg/m2 there was a 2.4-fold increase of the prevalence of high blood pressure in carriers of the M174 allele compared with in homozygotes for the T174 allele, whereas no association was detected in subjects with body mass index26 kg/m2. The association between high blood pressure and M235T was not significant in either group. The T174M and M235T genotype distributions did not differ between survivors of myocardial infarction and controls.These data suggest that the AGT gene could be involved in the predisposition to high blood pressure in non-overweight, but not in overweight men, possibly reflecting genetically different types of hypertension. No significant impact of the AGT locus in the risk of non-fatal myocardial infarction was detected.

By applying an imputation strategy based on the 1000 Genomes project to two genome-wide association studies (GWAS), we detected a susceptibility locus for venous thrombosis on chromosome 11p11.2 that was missed by previous GWAS analyses that had been conducted on the same datasets. A comprehensive linkage disequilibrium and haplotype analysis of the whole locus where twelve SNPs exhibited association p-values lower than 2.23 10(-11) and the use of independent case-control samples demonstrated that the culprit variant was a rare variant located ~1 Mb away from the original hits, not tagged by current genome-wide genotyping arrays and even not well imputed in the original GWAS samples. This variant was in fact the rs1799963, also known as the FII G20210A prothrombin mutation. This work may be of major interest not only for its scientific impact but also for its methodological findings.

We conducted the present study to determine whether the angiotensin II type I receptor (AT1) gene might be implicated in human essential hypertension by using case-control and linkage studies. The entire coding and 3' untranslated regions of the AT1 receptor gene (2.2 kb) were amplified by polymerase chain reaction and submitted to single-strand conformation polymorphism in 60 hypertensive subjects with a familial susceptibility. We identified five polymorphisms (T573-->C, A1062-->G, A1166-->C, G1517-->T, and A1878-->G). However, no mutations that alter the encoded amino acid sequence were detected. A case-control study performed on white hypertensive (n = 206; blood pressure, 168 +/- 16/103 +/- 9 mm Hg) and normotensive (n = 298; blood pressure, 122 +/- 10/75 +/- 9 mm Hg) subjects using three of five polymorphisms showed a significant increase in allelic frequency of C1166 in hypertensive subjects (0.36 versus 0.28 for normotensive subjects, chi 2 = 6.8, P < .01). Frequencies for the alleles of the other two polymorphisms (T573-->C, A1878-->G) were similar in both groups. We performed a linkage study using the affected sib pair method and a highly polymorphic marker of the AT1 receptor gene. There was no evidence for linkage in 267 sib pairs analyzed from 138 pedigrees. These findings would be compatible with a common variant of the AT1 receptor imparting a small effect on blood pressure; further studies will be needed to address this possibility.

Non-insulin-dependent diabetes mellitus (NIDDM) is considered a model of premature atherosclerosis with a strong genetic component. We have investigated the role of angiotensin-converting enzyme (ACE; EC 3.4.15.1) gene in 316 unrelated NIDDM individuals, 132 who had myocardial infarction or significant coronary stenoses and 184 with no history of coronary heart disease (CHD). A deletion-polymorphism in the ACE gene was recently reported to be associated with myocardial infarction especially in people classified as low risk. Here we report that the D allele of the ACE gene is a strong and independent risk factor for CHD in NIDDM patients. The D allele is associated with early-onset CHD in NIDDM, independently of hypertension and lipid values. A progressively increasing relative risk in individuals heterozygous and homozygous for the D allele was observed (odds ratios of 1.41 and 2.35, respectively; P < 0.007), suggesting a codominant effect on the cardiovascular risk. The percentage of CHD attributable to the ACE deletion allele was 24% in this NIDDM population. Identification of NIDDM patients carrying this putative CHD-susceptibility genotype would help early detection and treatment of CHD.

The angiotensin I-converting enzyme gene is one of the major genes of the renin-angiotensin and kallikrein-kinin systems and is a candidate gene for several cardiovascular diseases for which a genetic predisposition has been established. Based on analysis of the level of the enzyme in plasma, a genetic polymorphism of its expression has been well characterized. Use of a DNA marker on the angiotensin I-converting enzyme gene has shown that the gene polymorphism is located within the angiotensin I-converting enzyme gene itself. This review summarizes the results of various studies of this polymorphism in cardiovascular diseases and the hypotheses that can be proposed to explain this effect.

Background: Venous Thrombosis (VT) is a common multifactorial disease associated with a major public health burden. Genetics factors are known to contribute to the susceptibility of the disease but how many genes are involved and their contribution to VT risk still remain obscure. We aimed to identify genetic variants associated with VT risk. Methodology/Principal Findings: We conducted a genome-wide association study (GWAS) based on 551,141 SNPs genotyped in 1,542 cases and 1,110 controls. Twelve SNPs reached the genome-wide significance level of 2.0×10−8 and encompassed four known VT-associated loci, ABO, F5, F11 and FGG. By means of haplotype analyses, we also provided novel arguments in favor of a role of HIVEP1, PROCR and STAB2, three loci recently hypothesized to participate in the susceptibility to VT. However, no novel VT-associated loci came out of our GWAS. Using a recently proposed statistical methodology, we also showed that common variants could explain about 35% of the genetic variance underlying VT susceptibility among which 3% could be attributable to the main identified VT loci. This analysis additionally suggested that the common variants left to be identified are not uniformly distributed across the genome and that chromosome 20, itself, could contribute to ∼7% of the total genetic variance. Conclusions/Significance: This study might also provide a valuable source of information to expand our understanding of biological mechanisms regulating quantitative biomarkers for VT.

To compare the amount of drug quantified by a score needed to control blood pressure in two groups of overweight hypertensive patients, receiving or not receiving a hypocaloric diet.Randomized controlled clinical trial.Two hospital outpatient hypertension clinics.Fifty-four subjects with a DBP between 95 and 110 mmHg and a weightor = 110% of the ideal weight.Allocation to either drug treatment (DT) or hypocaloric diet (HD). In the HD group, after 2 months, an antihypertensive drug was administered to the subjects with a DBPor = 90 mmHg, following the same scheme protocol as in the DT group. Subjects were followed during 10 months by a clinician only in the DT group and by a clinician and a dietician in the HD group.Score of treatment: hydrochlorothiazide 25 mg [score = 1] with, as needed to obtain a DBP90 mmHg, the addiction of enalapril 10 mg [score = 2], 20 mg [score = 3], and nifedipine 40 mg [score = 4].At the end of the trial, 5 subjects were lost to follow-up in the HD group and 1 in the DT group (p0.05). Mean weight loss was 5.9 kg (sd = 1.2) in the HD and 2.3 kg (sd = 0.7) in the DT group (p = 0.02). Mean decrease in DBP was 18 mmHg (sd = 7) and 15 mmHg (sd = 8) in HD and DT groups respectively (p = 0.36). Mean DBP was 84 mmHg (sd = 7.8) in the HD group and 85 mmHg (sd = 7.2) in the DT group. In the HD group, 8 (38.1%) subjects had a DBP90 mmHg without any drug treatment. The mean drug treatment score was 0.86 (sd = 0.91) in the HD and 1.52 (0.70) in the DT group (p = 0.01).This study shows that in overweight hypertensives, the quantity of drug needed to achieve an acceptable level of BP is nearly reduced by 50% when an efficient hypocaloric diet is prescribed simultaneously.