Apolipoprotein C-III Strongly Correlates with Activated Factor VII-Anti-Thrombin Complex: An Additional Link between Plasma Lipids and Coagulation.

Activated factor VII-anti-thrombin (FVIIa-AT) complex is a potential biomarker of pro-thrombotic diathesis reflecting FVIIa-tissue factor (TF) interaction and has been associated with mortality in patients with coronary artery disease (CAD). Previous data indicated plasma lipids as predictors of FVIIa-AT variability, and plasma lipoproteins as potential stimulators of the coagulation cascade. Our aim was to evaluate the relationships between FVIIa-AT plasma concentration and a broad apolipoprotein profile (including ApoA-I, ApoB, ApoC-III and ApoE). Within the framework of the observational Verona Heart Study, we selected 666 subjects (131 CAD-free and 535 CAD, 75.4% males, mean age: 61.1 ± 10.9 years) not taking anticoagulant drugs and for whom plasma samples were available for both FVIIa-AT assay and a complete lipid profile. Plasma concentration of FVIIa-AT levels significantly and directly correlated with total and high-density lipoprotein cholesterol, triglycerides, ApoA-I, ApoC-III and ApoE levels. ApoC-III showed the strongest correlation (R = 0.235, p = 7.7 × 10-10), confirmed in all the sub-group analyses (males/females and CAD/CAD-free). Only ApoC-III remained associated with FVIIa-AT plasma concentration, even after adjustment for sex, age, CAD diagnosis, body mass index, renal function, smoking status, lipid-lowering therapies and FVIIa levels. The APOC3 gene locus-tagging polymorphism rs964184, previously linked with cardiovascular risk and plasma lipids by genome-wide association studies, was associated with both ApoC-III and FVIIa-AT plasma concentration. Our results indicate a strong association between ApoC-III and FVIIa-AT levels, thereby suggesting that an increased ApoC-III concentration may identify subjects with a pro-thrombotic diathesis characterized by an enhanced TF-FVIIa interaction and activity.

An integrated genomic-transcriptomic approach supports a role for the proto-oncogene BCL3 in atherosclerosis.

Data with border-line statistical significance, copiously generated in genome-wide association studies of coronary artery disease (CAD), could include functionally relevant associations. We propose an integrated genomic and transcriptomic approach for unravelling new potential genetic signatures of atherosclerosis. Fifteen among 91 single nucleotide polymorphisms (SNPs) were first selected for association in a sex- and age-adjusted model by examining 510 patients with CAD and myocardial infarction and 388 subjects with normal coronary arteries (CAD-free) in the replication stages of a genome-wide association study. We investigated the expression of 71 genes proximal to the 15 tag-SNPs by two subsequent steps of microarray-based mRNA profiling, the former in vascular smooth muscle cell populations, isolated from non-atherosclerotic and atherosclerotic human carotid portions, and the latter in whole carotid specimens. BCL3 and PVRL2, contiguously located on chromosome 19, and ABCA1, extensively investigated before, were found to be differentially expressed. BCL3 and PVRL2 SNPs were genotyped within a second population of CAD patients (n=442) and compared with CAD-free subjects (n=393). The carriership of the BCL3 rs2965169 G allele was more represented among CAD patients and remained independently associated with CAD after adjustment for all the traditional cardiovascular risk factors (odds ratio=1.70 with 95% confidence interval 1.07-2.71), while the BCL3 rs8100239 A allele correlated with metabolic abnormalities. The up-regulation of BCL3 mRNA levels in atherosclerotic tissue samples was consistent with BCL3 protein expression, which was detected by immunostaining in the intima-media of atherosclerotic specimens, but not within non-atherosclerotic ones. Our integrated approach suggests a role for BCL3 in cardiovascular diseases.

Modulation of factor V levels in plasma by polymorphisms in the C2 domain.

OBJECTIVE: Functional polymorphisms contributing to coagulation factor levels are preferential markers for association studies aimed at identifying prothrombic genetic components. METHODS AND RESULTS: Factor V (FV) microsatellite genotypes were found to be associated with FV levels (P=0.003). Single nucleotide polymorphisms analysis and sequencing of the promoter and of coding regions identified two polymorphisms (Met2120Thr, Asp2194Gly) present in 20% of the population (n=1013) that are responsible for genotype-phenotype associations. The effect of the Met2120Thr polymorphism, both in plasma (mean reduction of FV level in the heterozygous condition: 25%) and in recombinant FV studies (34% reduction), was comparable to that of the Asp2194Gly change (20% and 34%, respectively). The study of 10 subjects with a rare genotype indicated that the Asp2194Gly substitution is the functional determinant of the reduced FV levels associated with the FVHR2 haplotype. Among Leiden carriers, the doubly heterozygous condition for FV2120Thr was found to be associated with a significantly increased activated protein-C resistance (APCR) (P<0.05), and the doubly heterozygous condition for FV2194Gly was found to be more frequent (P=0.009) in symptomatic than in asymptomatic subjects. CONCLUSIONS: Extensive analysis of FV polymorphisms indicated that changes in the C2 domain modulate FV levels and might increase APCR and thrombotic risk in FV Leiden carriers through a pseudohomozygous mechanism.

Predictive value of D-dimer test for recurrent venous thromboembolism after anticoagulation withdrawal in subjects with a previous idiopathic event and in carriers of congenital thrombophilia.

BACKGROUND: We have shown that normal D-dimer levels obtained after the discontinuation of oral anticoagulant treatment (OAT) has a high negative predictive value for recurrent venous thromboembolism (VTE). The aim of the present study was to assess the predictive value of D-dimer for recurrent VTE in subjects with a previous unprovoked event who are either carriers of inherited thrombophilia or not. METHODS AND RESULTS: We prospectively evaluated 599 patients (301 males) with a previous VTE episode. They were repeatedly examined for D-dimer levels after OAT withdrawal and were screened for inherited thrombophilic alterations. Alterations were detected in 130 patients (21.7%), factor V Leiden (70 patients; 2 of whom were homozygotes) and prothrombin mutation (38 patients) were the most prevalent ones. Recurrent events were recorded in 58 subjects (9.7%) during a follow-up of 870.7 patient-years. Altered D-dimer levels at 1 month after OAT withdrawal were associated with a higher rate of subsequent recurrence in all subjects investigated, especially in those with an unprovoked qualifying VTE event (hazard ratio, 2.43; 95% confidence interval, 1.18 to 4.61) and in those with thrombophilia (hazard ratio, 8.34; 95% confidence interval, 2.72 to 17.43). The higher relative risk for recurrence of altered D-dimer was confirmed by multivariate analysis after adjustment for other risk factors. The negative predictive value of D-dimer was 92.9% and 95.8% in subjects with an unprovoked qualifying event or with thrombophilia, respectively. CONCLUSIONS: D-dimer levels measured 1 month after OAT withdrawal have a high negative predictive value for recurrence in subjects with unprovoked VTE who are either carriers or not carriers of congenital thrombophilia.