Common susceptibility alleles are unlikely to contribute as strongly as the FV and ABO loci to VTE risk: results from a GWAS approach.

Venous thromboembolism (VTE) is a complex disease that has a major genetic component of risk. To identify genetic factors that may modify the risk of VTE, we conducted a genome-wide association study by analyzing approximately 317 000 single nucleotide polymorphisms (SNPs) in 453 VTE cases and 1327 controls. Only 3 SNPs located in the FV and ABO blood group genes were found associated with VTE at a genome-wide significant level of 1.7 x 10(-7). Detailed analysis of these SNPs in additional cohorts of more than 1700 cases and 1400 controls revealed that the association observed at the FV locus was the result of the increased risk mediated by the FV Leiden mutation, whereas O and A2 blood groups were found to be at lower risk for VTE. Apart from the FV and ABO loci, no other locus was found strongly associated with VTE. However, using this large cohort of subjects, we were able to replicate the mild effects of 2 nonsynonymous SNPs, rs1613662 in GP6 and rs13146272 in CYP4V2, recently suspected to be associated with VTE.

Effect of diet-induced weight loss on endothelial dysfunction: early improvement after the first week of dieting.

Obesity is associated with impaired endothelial function, and this may lead to increased cardiovascular risk. To gain insight into the beneficial effects of diet-induced weight loss on endothelial function, endothelium-dependent, flow-mediated dilation (FMD) of the brachial artery and several metabolic and inflammatory markers were assessed in 40 obese women (BMI 34.9 ± 4.88 kg/m(2)) at baseline, after the 1st week and after 5 months on a low-calorie diet of 5.0 MJ/day. Twenty lean women served as controls. At entry, the obese women had a lower FMD than the lean women (7.7 ± 1.8 vs. 11.5 ± 4.2%, p < 0.001). After 1 week of the intervention and 4% reduction of BMI, FMD improved by 22% (p = 0.005), and a decrease in circulating triglycerides, insulin, leptin, tissue type plasminogen activator and its inhibitor, von Willebrand factor, C-reactive protein and tumor necrosis factor receptor 1 was observed. Improvement of FMD was associated only with a decrease in BMI (r = 0.39, p = 0.03). Twenty-two women completed the weight reduction program and reduced their BMI by 16%. FMD was further improved by 64% (to 12.4 ± 5.3%, p = 0.001) and became comparable to that of lean women. None of the significant changes in the observed parameters was associated with improvement of FMD at the end of the program. Improvements in obesity-related endothelial dysfunction began in the 1st week of dieting and continued during the following months of this simple non-pharmacological lifestyle modification to reach normalisation of endothelial function. The favourable effect of dieting on endothelial function is independent of the accompanying improvement of classical risk factors.

Platelet microparticles: a new player in malaria parasite cytoadherence to human brain endothelium.

Cerebral malaria (CM) is characterized by accumulation of circulating cells within brain microvessels, among which platelets play an important role. In vitro, platelets modulate the cytoadherence of Plasmodium falciparum-parasitized red blood cells (PRBCs) to brain endothelial cells. Here we show for the first time that platelet microparticles (PMPs) are able to bind to PRBCs, thereby transferring platelet antigens to the PRBC surface. This binding is largely specific to PRBCs, because PMPs show little adherence to normal red blood cells. PMP adherence is also dependent on the P. falciparum erythrocyte membrane protein 1 variant expressed by PRBCs. PMP binding to PRBCs decreases after neutralization of PRBC surface proteins by trypsin or after treatment of PMPs with a mAb to platelet-endothelial cell adhesion molecule-1 (CD31) and glycoprotein IV (CD36). Furthermore, PMP uptake is a dynamic process that can be achieved by human brain endothelial cells (HBECs), inducing changes in the endothelial phenotype. Lastly, PMPs dramatically increase PRBC cytoadherence to HBECs. In conclusion, our study identifies several mechanisms by which PMPs may participate in CM pathogenesis while interacting with both PRBCs and HBECs. PMPs thereby provide a novel target for antagonizing interactions between vascular cells that promote microvascular sludging and blood brain barrier alteration during CM.

Respective contribution of conventional risk factors and antihypertensive treatment to stable angina pectoris and acute coronary syndrome as the first presentation of coronary heart disease: the PRIME Study.

OBJECTIVE: To test whether conventional risk factors and antihypertensive treatment were more predictive of stable angina (SA) than acute coronary syndrome (ACS) as the first presentation of coronary heart disease (CHD). DESIGN: We used data from the PRIME Study (Prospective Epidemiological Study of Myocardial Infarction), a prospective cohort of 9758 asymptomatic middle-aged men recruited from WHO MONICA centers in Northern Ireland and France between 1991 and 1993. SA and ACS events were registered during 5 years of follow-up. METHODS: Hazard ratios (HRs) of each risk factor measured at baseline for SA and ACS events were assessed using separate Cox proportional hazard models. Difference between HRs was estimated by the bootstrap method. RESULTS: After 5 years of follow-up, there were 114 SA and 178 ACS as the first presentation of CHD. Diastolic blood pressure [adjusted HRs for 1 standard deviation increase = 1.34; 95% confidence interval (CI): 1.17-1.54 vs. 1.04; 95% CI: 0.87-1.25; P for comparison between HRs = 0.012], and possibly cigarette smoking over or equal to 20 pack-years (adjusted HR = 2.07; 95% CI: 1.43-2.99 vs. 1.29; 95% CI: 0.83-2.01; P for comparison between HRs = 0.062) were more predictive of ACS than SA, whereas this was the opposite for antihypertensive treatment (adjusted HR = 2.18; 95% CI: 1.39-3.41 for SA vs. 1.28; 95% CI: 0.85-1.93 for ACS, P for comparison between HRs = 0.049). CONCLUSION: The present data support that SA and ACS, as the first presentation of CHD, may not share exactly the same determinants.

Relationship between aspirin and clopidogrel responses in acute coronary syndrome and clinical predictors of non response.

OBJECTIVES: We have prospectively investigated the association between aspirin and clopidogrel responses and the clinical predictors of non response. METHODS: 635 Non ST Elevation Acute Coronary Syndrome (NSTE ACS) patients were included and received loading doses of 250 mg aspirin and 600 mg clopidogrel. We analyzed post-treatment maximal intensity of arachidonic acid and ADP-induced platelet aggregation (AA-Ag and ADP-Ag) and Platelet Reactivity Index of VAsodilator-Stimulated Phosphoprotein (PRI VASP). Aspirin and clopidogrel non responses were defined respectively by AA-Ag>30% and ADP-Ag>70%. RESULTS: Aspirin non responders patients had significantly higher ADP-Ag and PRI VASP than aspirin responders: 63.7+/-15.9% vs 55+/-19% (p=0.0001) and 73.6+/-13.3% vs 53+/-23% (p=0.0001) respectively and the rate of clopidogrel non responders was higher among aspirin non responders than aspirin responders: 36.7% vs 22.7% (p=0.003). In addition, clopidogrel non responders had significantly higher AA-Ag and rate of aspirin non responders than clopidogrel responders: 21.6+/-24% vs 10.3+/-19% (p=0.0001) and 22.8% vs 12.9% (p=0.003) respectively. Age and Body Mass Index (BMI) were significantly associated with non response to Clopidogrel (p=0.035 and 0.02 respectively) and diabetes mellitus by trend (p=0.07). CONCLUSION: We observed a relationship between aspirin and clopidogrel non responses and an association between age, BMI and diabetes mellitus and clopidogrel response.

Contribution of novel biomarkers to incident stable angina and acute coronary syndrome: the PRIME Study.

AIMS: To compare whether novel inflammatory and haemostatic biomarkers are more predictive of well-characterized incident acute coronary syndrome (ACS) than stable angina (SA). METHODS AND RESULTS: We used data from the PRIME Study, a prospective cohort of 9758 asymptomatic middle-aged men recruited in Northern Ireland and France between 1991 and 1993. A nested case-control study was established with the baseline plasma sample of 269 incident cases and 538 matched controls. Odds ratios (ORs) for SA and ACS were estimated by conditional logistic regression analysis. After 5 years of follow-up, 107 incident SA and 162 ACS cases were validated. After adjustment for traditional risk factors, higher circulating levels of hs-CRP, ICAM1, interleukin 6 and interleukin 18 were equally predictive of SA and ACS (all P-values of OR comparison >0.05). In contrast, elevated levels of fibrinogen, von Willebrand factor, and possibly higher level of D-dimers and lower level of tissue factor pathway inhibitor were associated with ACS only. The comparison of the ORs showed a statistically significant difference for von Willebrand factor only [OR(4th vs. 1st quartile) = 2.99 (1.49-6.02) for ACS vs. 0.80 (0.33-1.94) for SA; P(z test) = 0.02]. CONCLUSION: This is the first population-based study suggesting that higher levels of circulating haemostatic markers and of von Willebrand factor, in particular, are significantly more predictive of incident ACS than SA.

Metabolic syndrome, haemostasis and thrombosis.

The metabolic syndrome (metS), a concurrence of abdominal fat, disturbed glucose and insulin metabolism, dyslipidemia, and hypertension has been strongly associated not only with subsequent development of type 2 diabetes but also with atherothrombosis. The physiopathology of this association is complex. The metS affects the thrombogenicity of circulating blood. Apart from its effect on platelets, a procoagulant and hypofibrinolytic state has been identified; mainly the result of the inflammatory state, dyslipidemia, and liver fat accumulation that accompany the MetS. Among haemostasis disturbances, the strong rise in the inhibitor of plasminogen activator type 1 plasma level is the most documented abnormality implicating the participation of the oxidative stress and inflammatory state developed during the metS. Endothelial dysfunction is also a central feature. Moreover, secretion products of fat tissues (adipokines) are now thought to have direct modulating effects on the vascular and the circulating cells. In support of these data, the metS, may predispose not only to atherosclerosis but also to venous thrombosis.

Effect of cytochrome p450 polymorphisms on platelet reactivity after treatment with clopidogrel in acute coronary syndrome.

Genetic polymorphisms of cytochrome P450 (CYP) isoforms may promote variability in platelet response to clopidogrel. This study was conducted to analyze, in 603 patients with non-ST elevation acute coronary syndromes, the effect of CYP3A4, CYP3A5, and CYP2C19 gene polymorphisms on clopidogrel response and post-treatment platelet reactivity assessed by adenosine diphosphate (ADP)-induced platelet aggregation, vasodilator-stimulated phosphoprotein phosphorylation index, and ADP-induced P-selectin expression. The CYP2C19*2 polymorphism was significantly associated with ADP-induced platelet aggregation, vasodilator-stimulated phosphoprotein phosphorylation index, and ADP-induced P-selectin expression in recessive (p <0.01, p <0.007, and p <0.06, respectively) and codominant (p <0.08, p <0.0001, and p <0.009, respectively) models, but the CYP3A4*1B and CYP3A5*3 polymorphisms were not. The CYP2C19*2 allele carriers exhibited the highest platelet index levels in multivariate analysis (p = 0.03). After covariate adjustment, the CYP2C19*2 allele was more frequent in clopidogrel nonresponders, defined by persistent high post-treatment platelet reactivity (ADP-induced platelet aggregation >70%; p = 0.03). In conclusion, the present data suggest that the CYPC19*2 allele influences post-treatment platelet reactivity and clopidogrel response in patients with non-ST elevation acute coronary syndromes.

Polymorphism A36G of the tumor necrosis factor receptor 1 gene is associated with PAI-1 levels in obese women.

The tumor necrosis factor (TNF) pathway may be implicated in etiopathogenesis of PAI-1 overexpression during obesity. The aim of this study was to investigate the influence of polymorphism A36G of the TNF receptor 1 (TNFRSF1A +36A/G) on plasma concentrations of PAI-1 in 163 obese (31 with the metabolic syndrome, MetS) and 150 lean, healthy women. Genotypic and allele frequencies did not significantly differ between obese and lean subjects. TNFRSF1A genotypes were significantly associated with sTNFR1 plasma levels in obese women only (p < 0.01); TNFRSF1A +36G/G obese carriers exhibited higher sTNFR1 and PAI-1 levels than A carriers (p < 0.01 and p < 0.05, respectively). In obese women, the presence of the MetS significantly potentiated the elevation of sTNFR1 and PAI-1 levels observed in the TNFRSF1A + 36G/G carriers. Our results suggest that association between TNFRSF1A +36G/G genotype and the MetS renders obese women more prone to activation of the TNF pathway reflected by high circulating sTNFR1 and PAI-1 levels.

Lack of association between the 807 C/T polymorphism of glycoprotein Ia gene and post-treatment platelet reactivity after aspirin and clopidogrel in patients with acute coronary syndrome.

Variability in platelet response to antiplatelet therapy and its clinical relevance have been well described. However, the underlying mechanisms remain unclear. It was the aim of the present study to assess whether the response to aspirin and clopidogrel may be influenced by the 807 C/T polymorphism of the glycoprotein Ia (GpIa) gene in patients with non-ST elevation acute coronary syndrome (NSTE ACS). Six hundred one NSTE ACS patients were included in our study and were divided into three groups: CC homozygotes, CT heterozygotes ad TT homozygotes. All patients received loading doses of 600 mg clopidogrel and 250 mg aspirin at least 12 hours before blood samples were drawn. Post-treatment platelet reactivity was assessed by post treatment ADP 10 microM-induced platelet aggregation (ADP-Ag), VASP phosphorylation (PRI VASP) and P-selectin expression. Non-response to dual antiplatelet therapy was defined by high post-treatment platelet reactivity (HPPR=ADP-Ag > 70%). Significant variability in the distribution of platelet parameters was observed in the overall study population. No significant difference in platelet parameters profiles was observed within patients having the same genotype, for ADP-Ag (p=0.33), PRIVASP (p=0.72) and P-selectin expression (p=0.37). The genotype frequencies of the 807 C/T polymorphism of the GpIa gene were similar in responders and non-responders defined by persistent HPPR (p=0.104). In conclusion, our study did not show any influence of 807 C/T polymorphism of GpIa gene on post-treatment platelet reactivity assessed by ADP-Ag, PRI VASP or P-selectin expression in 601 NSTE ACS patients.

ADP-induced platelet aggregation and platelet reactivity index VASP are good predictive markers for clinical outcomes in non-ST elevation acute coronary syndrome.

Clopidogrel responsiveness has been proposed to be involved in recurrent ischemic events after stenting for non-ST elevation acute coronary syndromes (NSTE ACS). However, its biological definition is not consensual. We assess the value of ADP-induced platelet aggregation (ADP-Ag) and platelet reactivity index VASP (PRI VASP) in predicting recurrent ischemic events in patients with NSTE ACS undergoing percutaneous coronary intervention (PCI). We studied 195 consecutive NSTE ACS patients undergoing PCI after a 600 mg loading dose of clopidogrel. ADP-Ag and PRI VASP were analysed. The primary end-point was recurrent ischemic events within 30 days of PCI. It occurred in 14 patients (7%). Construction of ROC curves to examine the value of predictive models showed that sensitivity and specificity for primary endpoint were 79% and 76%, respectively, for a maximal intensity of ADP-Ag >or=70%, 93% and 50% for PRIVASP > 53%. The positive and negative predictive values were 21% and 98%, respectively, for ADP-Ag >or=70%, 12% and 99% for PRIVASP > 53%. In patients with NSTE ACS undergoing PCI, ADP-Ag and PRI VASP identify low responders to clopidogrel with an increased risk of recurrent ischemic events with respective cut-off values of 70% and 53%.

PAI-1 and the metabolic syndrome: links, causes, and consequences.

The link between plasminogen activator inhibitor (PAI)-1 and the metabolic syndrome with obesity was established many years ago. Increased PAI-1 level can be now considered a true component of the syndrome. The metabolic syndrome is associated with an increased risk of developing cardiovascular disease, and PAI-1 overexpression may participate in this process. The mechanisms of PAI-1 overexpression during obesity are complex, and it is conceivable that several inducers are involved at the same time at several sites of synthesis. Interestingly, recent in vitro and in vivo studies showed that besides its role in atherothrombosis, PAI-1 is also implicated in adipose tissue development and in the control of insulin signaling in adipocytes. These findings suggest PAI-1 inhibitors serve in the control of atherothrombosis and insulin resistance.

Modulation of adipose tissue development by pharmacological inhibition of PAI-1.

OBJECTIVE: The effect of a novel small molecule plasminogen activator inhibitor (PAI-1) inhibitor on adipose tissue physiology was investigated. METHODS AND RESULTS: In human preadipocyte cultures, PAI-039 inhibited both basal and glucose-stimulated increases in active PAI-1 antigen, yet had no effect on PAI-1 mRNA, suggesting a direct inactivation of PAI-1. Differentiation of human preadipocytes to adipocytes was associated with leptin synthesis, which was significantly reduced in the presence of PAI-039, together with an atypical adipocyte morphology characterized by a reduction in the size and number of lipid containing vesicles. In a model of diet-induced obesity, pair-fed C57 Bl/6 mice administered PAI-039 in a high-fat diet exhibited a dose-dependent reduction in body weight, epididymal adipose tissue weight, adipocyte volume, and circulating plasma active PAI-1. Plasma glucose, triglycerides, and leptin were also significantly reduced in drug-treated mice, and concentrations of PAI-039 associated with these physiological effects were near the in vitro IC50 for the inhibition of PAI-1. CONCLUSIONS: Our results indicate that a small molecule inactivator of PAI-1 can neutralize glucose-stimulated increases in PAI-1 in human preadipocyte cultures, reduce adipocyte differentiation, and prevent the development of diet-induced obesity. These data suggest the pharmacological inhibition of PAI-1 could be beneficial in diseases associated with expansion of adipose tissue mass.

Plasma cystatin-C and development of coronary heart disease: The PRIME Study.

The pathogenesis of ischemic coronary events involves degradation of the extracellular matrix in atherosclerotic lesions. The cysteine protease inhibitor cystatin-C may be involved in this phenomenon. The association of plasma cystatin-C with the incidence of myocardial infarction-coronary death and angina, was examined in a nested case-control (two controls per case) design within the prospective cohort study (Prospective Epidemiological Study of Myocardial Infarction (PRIME Study)) which included 9,758 men aged 50-59 years who were free of coronary heart disease (CHD) on entry and followed for a 5-year period. Three hundred and thirteen participants suffered myocardial infarction or coronary death (n = 159) or angina pectoris (n = 154) during follow-up. Cystatin-C was positively correlated with body mass index (BMI), low-density lipoprotein (LDL)-cholesterol, triglycerides and several inflammatory markers such as fibrinogen (r = 0.18), C-reactive protein (CRP) (r = 0.24), interleukin-6 (= 0.20), tumor necrosis factor-alpha (TNFalpha) (r = 0.27) and two TNFalpha receptors: TNFR1A (r = 0.43) and TNFR1B (r = 0.41); and negatively with high-density lipoprotein (HDL)-cholesterol (r = -0.25). After adjustment for traditional risk factors (age, diabetes, smoking, hypertension, BMI, triglycerides, LDL- and HDL-cholesterol), cystatin-C was significantly associated with the occurrence of the first ischemic coronary event. However, this association was no longer significant when CRP was included in the analysis. A decrease in glomerular filtration rate did not explain higher cystatin-C in cases than in controls. Cystatin-C appears to participate in the inflammatory phenomenon observed in the atherosclerotic process. Cystatin-C is not a more predictive risk marker of CHD than CRP or interleukin-6, but could be useful in detecting moderate chronic renal disease.

The TNF alpha converting enzyme (TACE/ADAM17) is expressed in the atherosclerotic lesions of apolipoprotein E-deficient mice: possible contribution to elevated plasma levels of soluble TNF alpha receptors.

TNF alpha converting enzyme (TACE) critically regulates the inflammatory processes as it releases from the cell surface several transmembrane proteins, including TNFalpha (TNF) and its receptors TNFR1 and TNFR2. We investigated the expression of TACE in atherosclerotic lesions of apolipoproteinE-deficient (apoE (-/-)) mice. Five-week-old apoE(-/-) male mice were fed a high-fat diet and examined at 5, 10, 15 and 25 weeks of age. A group of wild-type C57BL/6 mice (WT) fed the high-fat diet for 25 weeks was included. In apoE(-/-) mice, lesions progressed with time in both aortic sinus and arch, in which TACE immunostaining also increased particularly between 5 and 15 weeks. TACE expression was also observed in human atherosclerotic plaques. The plasma levels of soluble TNFR1 and TNFR2 rose with atherosclerosis. In the 25-week-old WT mice, no lesions were observed and the plasma levels of TNFRs were 17% of those of age-matched apoE(-/-) mice. Incubated aortas of 25-week-old apoE(-/-) mice released much higher amounts of sTNF and sTNFRs than did aortas of 5-week-old apoE(-/-) mice or 25-week-old WT mice. Active TACE was expressed at the surface of macrophages isolated from apoE(-/-) mice. In conclusion, TACE expression is associated with lesions in atherosclerosis-prone sites. Our data suggest that atherosclerotic lesions-expressing TACE may contribute to the elevated levels of circulating sTNFRs.

Tiplaxtinin impairs nutritionally induced obesity in mice.

To investigate the effect of tiplaxtinin, designed as a synthetic inhibitor of plasminogen activator inhibitor-1 (PAI-1), on obesity, male C57Bl/6 mice (13-14 weeks old) were kept on a high-fat diet (20.1 kJ/g) for four weeks without or with addition of tiplaxtinin (PAI-039) at a dose of 2 mg/g food. At the time of sacrifice, body weights were significantly lower in the inhibitor-treated mice (p < 0.0005). The weights of the isolated subcutaneous and gonadal fat deposits were also significantly lower (both p < 0.0005), associated with adipocyte hypotrophy. Inhibitor-treated adipose tissues displayed similar blood vessel size, but a higher blood vessel density. Fasting glucose and insulin levels, as well as glucose-tolerance tests were not significantly affected by the inhibitor treatment, whereas plasma triglyceride levels were significantly reduced (p = 0.02) and LDL-cholesterol levels significantly enhanced (p = 0.0002). Insulin-tolerance tests revealed significantly lower glucose levels at the end of the test in the inhibitor treated mice (p = 0.03). Thus, in this model of diet-induced obesity in mice administration of tiplaxtinin resulted in impaired adipose tissue development.

Insight into the nature of the CRP-coronary event association using Mendelian randomization.

BACKGROUND: It is unclear wheather the association between C-reactive protein (CRP) and incident coronary events is free from bias and confounding. Individuals homozygous for a +1444C>T polymorphism in the CRP gene have higher circulating concentrations of CRP. Since the distribution of this polymorphism occurs at random during gamete formation, its association with coronary events should not be biased or confounded. METHODS: We calculated the weighted mean difference in CRP between individuals with variants of the +1444C>T polymorphism in the CRP gene among 4,659 European men from six studies (genotype-intermediate phenotype studies). We used this difference together with data from previous observational studies to compute an expected odds ratio (OR) for non-fatal myocardial infarction (MI) among individuals homozygous for the T allele. We then performed four new genetic association studies (6,201 European men) to obtain a summary OR for the association between the +1444C>T polymorphism and non-fatal MI (genotype-disease studies). RESULTS: CRP was 0.68 mg/l [95% confidence interval (95% CI) 0.31-1.10; P = 0.0001] higher among subjects homozygous for the +1444-T allele, with no confounding by a range of covariates. The expected ORs among TT subjects for non-fatal MI corresponding to this difference in CRP was 1.20 (95% CI 1.07-1.38) using the Reykjavik Heart study data and 1.25 (1.09-1.43) for all observational studies to 2004. The estimate for the observed adjusted-OR for non-fatal MI among TT subjects was 1.01 (95% CI 0.74-1.38), lower than both expected ORs. CONCLUSIONS: A common CRP gene polymorphism is associated with important differences in CRP concentrations, free from confounding. The null association of this variant with coronary events suggests possible residual confounding (or reverse causation) in the CRP-coronary event association in observational studies, though the confidence limits are still compatible with a modest causal effect. Additional studies of genotype (or haplotype) and coronary events would help clarify whether or not the link between CRP and coronary events in observational studies is causal.

Quantification of thrombin activatable fibrinolysis inhibitor (TAFI) gene polymorphism effects on plasma levels of TAFI measured with assays insensitive to isoform-dependent artefact.

Reports have reappraised the genotype-dependent variation of Thrombin Activatable Fibrinolysis Inhibitor (TAFI), demonstrating that, in some enzyme-linked immunosorbent assays (ELISA), decreased antibody reactivity towards the TAFI 325 Ile isoform led to erroneous TAFI levels. Assays free of this artefact are required to evaluate the contribution of the TAFI gene polymorphisms to TAFI level variability. TAFI levels were measured in 209 individuals with both immunological and functional assays. Each assay was characterized, in particular for its reactivity towards the 325 Thr and Ile isoforms. Two ELISAs were found to have a lower reactivity towards the Ile isoform, leading to an overestimate of the magnitude of variation between two different genotypes. In contrast, one ELISA, as well as functional assays, was found to be free of genotype-dependent artefact constituting a reliable method to detect true quantitative variations of TAFI levels. Using these reliable methods, univariate and haplotype analyses revealed that TAFI gene polymorphisms explain 25% of TAFI level variability. This effect seems to be the consequence of the joint independent action of two polymorphisms, one in the 5' (G-1102T) and the other in the 3' region (T+1583A) of the TAFI gene.

Plasma PAI-1 levels are more strongly related to liver steatosis than to adipose tissue accumulation.

OBJECTIVE: Because obesity and insulin resistance (IR) are strongly associated with liver steatosis (LS), we investigated the relation between the degree of LS and plasminogen activator inhibitor-1 (PAI-1) in ob/ob mice, in C57/BL6 mice with alcoholic LS, and in severely obese humans. METHODS AND RESULTS: In both mouse models, plasma PAI-1 levels were associated with PAI-1 expression in the liver and with the degree of LS. Liver PAI-1 antigen was associated with the tumor necrosis factor receptor-II (TNFRII) antigen, whereas association with TNF antigen content was found in ob/ob mice only. No significant correlation between plasma PAI-1 and PAI-1 expression in adipose tissue of ob/ob mice was observed. Furthermore, the relation between plasma PAI-1 levels and body weight was positive in ob/ob mice but negative in C57/BL6 mice (both P<0.001). In humans, PAI-1 levels were correlated with the degree of LS, and 26% of plasma PAI-1 activity was independently explained by LS and serum insulin levels. CONCLUSIONS: Plasma PAI-1 levels are more closely related to fat accumulation and PAI-1 expression in the liver than in adipose tissue. In steatotic liver, PAI-1 antigen content is associated with those of TNF and TNFRII. Therefore, we suggest that TNF pathway dysregulation in LS could be involved in increased plasma PAI-1 in obesity with IR.

C-reactive protein, interleukin-6, and fibrinogen as predictors of coronary heart disease: the PRIME Study.

OBJECTIVE: This study was undertaken to examine the association of plasma inflammatory markers such as C-reactive protein (CRP), interleukin-6, and fibrinogen with the incidence of coronary heart disease within the prospective cohort study on myocardial infarction (PRIME study). METHODS AND RESULTS: Multiple risk factors were recorded at baseline in 9758 men aged 50 to 59 years who were free of coronary heart disease (CHD) on entry. Nested case-control comparisons were carried out on 317 participants who suffered myocardial infarction (MI)-coronary death (n=163) or angina (n=158) as an initial CHD event during a follow-up for 5 years. After adjustment for traditional risk factors, incident MI-coronary death, but not angina, was significantly associated with CRP, interleukin-6, and fibrinogen, but only interleukin-6 remained significantly associated with MI-coronary death when the 3 inflammatory markers were included in the model. The different interleukin-6 levels in Northern Ireland and France partly explained the difference in risk between these countries. Interleukin-6 appeared as a risk marker of MI-coronary death, and it improved the definition of CHD risk beyond LDL cholesterol. CONCLUSIONS: This association may reflect the underlying inflammatory reaction located in the atherosclerotic plaque or a genetic susceptibility on the part of CHD subjects to answer a proinflammatory stimulus and subsequent increase in hepatic CRP gene expression.