BACKGROUND
Genetic and environmental factors interact in determining the risk of
venous thromboembolism (VTE). The risk associated with the polymorphic
variants G1691A of factor V (Factor V Leiden,FVL), G20210A
of prothrombin (PT20210A) and C677T of
methylentetrahydrofolate reductase (C677T MTHFR) genes has
been investigated in many studies.
METHODS
We performed a pooled analysis of case-control and cohort studies
investigating in adults the association between each variant and VTE,
published on Pubmed, Embase or Google through January 2010. Authors of
eligible papers, were invited to provide all available individual data for
the pooling. The Odds Ratio (OR) for first VTE associated with each variant,
individually and combined with the others, were calculated with a random
effect model, in heterozygotes and homozygotes (dominant model for
FVL and PT20210A; recessive for
C677T MTHFR).
RESULTS
We analysed 31 databases, including 11,239 cases and 21,521 controls.
No significant association with VTE was found for homozygous C677T
MTHFR (OR: 1.38; 95% confidence intervals [CI]:
0.98–1.93), whereas the risk was increased in carriers of either
heterozygous FVL or PT20210 (OR=4.22; 95%
CI: 3.35–5.32; and OR=2.79;95% CI: 2.25–3.46, respectively),
in double hterozygotes (OR=3.42; 95%CI 1.64-7.13), and in homozygous FVL or
PT20210A (OR=11.45; 95%CI: 6.79-19.29; and OR: 2.79; 95%CI: 2.25 –
3.46, respectively). The stratified analyses showed a stronger effect of
FVL on individuals ≤45 years
(p-value for interaction = 0.036) and of
PT20210A in women using oral contraceptives
(p-value for interaction = 0.045).
CONCLUSIONS
In this large pooled analysis, inclusive of large studies like MEGA,
no effect was found for C677T MTHFR on VTE;
FVL and PT20210A were confirmed to be
moderate risk factors. Notably, double carriers of the two genetic variants
produced an impact on VTE risk significantly increased but weaker than
previously thought.
In connection with the embryo acceptance process after IVF procedure, endometrial cells surface receptors, extracellular matrix (ECM) molecules, endothelium and blood circulation factors were involved in remodelling of endometrium. Plasminogen activator inhibitor type 1 plays a significant role during the early phases of placental vascular remodelling and regulates the trophoblast invasion through controlling plasmin activity. Endometrial cell surface protein integrin alphaV/beta3, responsible for the adhesion of the embryo, has had also the same subunit beta3, which is component of integrin alphaIIb/beta3 connected with platelet aggregability. Prothrombin, furthermore, has had a debatable effect upon endothelial and mesenchymal cells and possible contribution on embryo vascular development. Confoundable data have been present about the role of coagulation factor V and its role for implantation. These and other coagulation factors have relatively common gene polymorphisms that enhanced their activity. This review discusses the effect of increased coagulation activity on implantation process, which is not yet fully determined. The establishment of the positive or negative impact of mother hypercoagulability on the success of embryo implantation after assisted reproduction technology could determine the timing of preventing anticoagulant therapy in women with history of early embryo loss.
The importance of genetic thrombophilic factors in the development of venous thromboembolism has been increasingly recognized. Factor V Leiden (FVL), prothrombin gene mutation G20210A (FII G20210), genetic variant C677T of the methylentetrahydrofolate reductase (MTHFR), as well as the polymorphism A2 (PlA2) in platelet glycoprotein IIb/IIIa were recently discussed. We analyzed the contribution of genetic thrombophilic factors to the pathogenesis of pulmonary embolism (PE) and their association with the early onset and recurrence of PE using DNA analysis methods. In this case control trial we found thrombophilic genetic variants in 58.8% of 51 patients with PE. FVL was found in 23.5% of the patients versus 7.1% of the 98 controls (p=0.01), PlA2 IIb/IIIa was found in 35.3% vs. 14.3% (p=0.03), and FII G20210A was found in 5.9% vs. 2.0% (NS). Patients with recurrent PE had a very high prevalence of genetic factors, 70.4%. High prevalence of FVL was found in patients under 45 years of age: 39.3% (OR=14.23, 95% CI=1.58-330.03, p=0.01) as well as in patients with recurrent incidence (37%, OR=7.647, 95% CI=2.27-26.44, p=0.001). FVL was also significantly higher in the subgroup of patients with PE combined with deep venous thrombosis (OR=6.500, 95% CI=1.81-23.76, p=0.002) in comparison with patients with isolated PE (OR=2.261, 95% CI=0.50-9.69). The carriers of FVL are at higher risk for early and recurrent PE events. High prevalence of PlA2 in PE patients evidently shows the impact of this polymorphism in PE development. A different treatment should be considered in carriers of thrombophilic defects.
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