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ABSTRACT: Increased ischemic stroke risk is observed in patients with inflammatory bowel disease (IBD). Causes and physiopathological aspects of cerebral infarct, in this specific population, are less often described. There is little information to provide guidelines for the best curative and preventive treatment. We report 2 cases of ischemic strokes due to internal carotid thrombus in patients during active phase of IBD. Ulceration of early atherosclerotic plaques activated by a hypercoagulation state may cause a thrombus. A combined therapy with heparin and corticosteroids was used for both our patients. Lysis of the thrombus was obtained after several days without surgical treatment and shown by ultrasonography. These cases highlight an aetiology of stroke in patients with IBD and use of a synergic treatment to respond to hypercoagulability in link with IBD. Benefits and safety of this therapy should be confirmed with clinical studies.
World Journal of Gastroenterology 02/2013; 19(5):773-5. · 2.47 Impact Factor
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ABSTRACT: Essential thrombocythemia and polycythemia vera are myeloproliferative disorders (MPD) with an elevated thrombotic risk. Leukocytosis has recently emerged as a new risk factor and there is increasing evidence that polymorphonuclear neutrophils (PMN) are involved. Procoagulant activity (PCA) of PMN in MPD has not yet been investigated. PCA of PMN from 22 patients with JAK2(V617F) positive MPD and 26 healthy subjects was studied using calibrated automated thrombography: in vitro thrombin generation induced with 1 pM tissue factor in the presence of added procoagulant phospholipids. There were no differences between patients and controls regarding the ability of PMN to increase thrombin generation. More surprisingly, basal thrombin generation in acellular MPD-plasma was found decreased for as yet unknown reasons. The presence of an active protein C pathway or platelets might provide a better insight into the coagulation phenotype in MPD.
Blood Cells Molecules and Diseases 02/2011; 46(3):235-8. · 2.35 Impact Factor
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ABSTRACT: Low-molecular-weight heparins (LMWHs) and fondaparinux are antithrombin dependent anticoagulant drugs considered to need no laboratory monitoring because of their reputedly predictable anticoagulant effect. However it has been suggested in the literature the existence of an inter-individual variability in response to LMWHs that would be not fully attributable to pharmacokinetics causes.
In order to separate pharmacokinetic from pharmacodynamics effects we studied in 12 platelet-depleted plasmas from normal donors the inhibitory effect on TG determined with the CAT of added UFH, 5 LMWHs and 2 oligosaccharides with anti-Xa activity only.
A concentration-dependent inhibition of thrombin generation was found with all molecules tested. The concentration-response relation was very different when the concentrations were expressed in anti-Xa unit but became very similar when expressed in anti-thrombin units regarding LMWHs. Most importantly, we noticed a large inter-individual variability of the inhibitory effects with all molecules tested, UFH and LMWHs alike. The IC40 value varied at least twofold between the highest and the lowest responder. For any given anti-Xa level of any heparin and of pentasaccharide the inhibition of the ETP showed scattering of around 25%.
In contrast to what is generally assumed the inter-individual variation of the in vitro pharmacodynamics response is equally high for UFH and any LMWH (~25%) and even for the synthetic pentasaccharide. This questions the rationale for standard dosage, the more so as in clinical practice pharmacokinetic variation (e.g. due to body weight) will add to this pharmacodynamic variability.
Thrombosis Research 01/2011; 127(1):29-34. · 2.44 Impact Factor
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ABSTRACT: This case describes the medical history of a 61-year-old woman treated for cerebral venous thrombosis (CVT) leading to diagnosis of essential thrombocythemia (ET). During treatment with unfractionated heparin, after initial improvement of clinical state, signs of cerebral hypertension reappeared. Although the platelet count decreased, heparin-induced thrombocytopenia (HIT) was only suspected 2 days later when it dropped below the standard 150 × 10(9) L(-1) threshold. HIT diagnosis was confirmed by the presence of anti-PF4/heparin IgG. This late finding was the cause of the extension of CVT with worsening of cerebral hypertension necessitating decompressive craniectomy. Elevated basal platelet count due to ET can delay diagnosis and treatment of HIT. In this case, physicians should be more attentive to platelet count variations rather than thrombocytopenia threshold.
Platelets 01/2011; 22(2):157-9. · 1.85 Impact Factor
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ABSTRACT: Cathepsin G (Cath G), a serine-protease found in neutrophils, has been reported to have effects that could either facilitate or impede coagulation. Thrombin generation (CAT method) was chosen to study its overall effect on the process, at a plasma concentration (240 nM) observed after neutrophil activation. Coagulation was triggered by tissue factor in the presence of platelets or phospholipid vesicles. To help identify potential targets of Cath G, plasma depleted of clotting factors or of inhibitors was used. Cath G induced a puzzling combination of two diverging effects of varying intensities depending on the phospholipid surface provided: accelerating the process under the three conditions (shortened clotting time by up to 30%), and impeding the process during the same thrombin generation time-course since thrombin peak and ETP (total thrombin potential) were decreased, up to 45% and 12%, respectively, suggestive of deficient prothrombinase. This is consistent with Cath G working on at least two targets in the coagulation cascade. Our data indicate that coagulation acceleration can be attributed neither to platelet activation and nor to activation of a clotting factor. When TFPI (tissue factor pathway inhibitor) was absent, no effect on lag time was observed and the anticoagulant activity of TFPI was decreased in the presence of Cath G. Consistent with the literature and the hypothesis of deficient prothrombinase, experiments using Russel's Viper Venom indicate that the anticoagulant effect can be attributed to a deleterious effect on factor V. The clinical relevance of these findings deserves to be studied.
Thrombosis and Haemostasis 09/2010; 104(3):514-22. · 5.04 Impact Factor
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ABSTRACT: It has been emphasized that polymorphonuclear leukocytes (PMN) participate in the regulation of coagulation. However, the mechanisms of action are not clear. Besides a procoagulant activity, anticoagulant or fibrinolytic properties are attributed to these cells. To explore their global effect, we have studied their involvement in the clot formation with thromboelastometry, which gives global view over the clotting process, in particular on the structure of the clot and on the kinetic of its formation.
PMN were isolated from healthy blood donors and resuspended into autologous platelet-free plasma. The ROTEM device was used. Coagulation was triggered only by adding calcium chloride. Thromboelastometric profiles of PMN-rich plasma (PMN-RP) were compared with autologous platelet-rich (PRP) and platelet-poor plasma (PPP). The inhibition of both tissue factor and intrinsic pathways was also studied.
The procoagulant activity of resting PMN was demonstrated as the initiation of fibrin formation with PMN-RP was significantly faster compared with both PRP and PPP. The kinetic of plasma clotting was remarkably improved with PMN-RP compared with PPP. However, the clot with PMN-RP had the same poor viscoelastical properties as PPP. Thromboelastometry gives a new point of view in the involvement of PMN in coagulation, in the absence of any PMN pre-activation. Their impact was centred on the kinetic and the facilitation of the clot formation.
Thrombosis Research 02/2008; 121(5):647-52. · 2.44 Impact Factor
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ABSTRACT: Essential thrombocythemia and polycythemia vera are myeloproliferative disorders (MPD) with an elevated thrombotic risk. Leukocytosis has recently emerged as a new risk factor and there is increasing evidence that polymorphonuclear neutrophils (PMN) are involved. Procoagulant activity (PCA) of PMN in MPD has not yet been investigated. PCA of PMN from 22 patients with JAK2V617F positive MPD and 26 healthy subjects was studied using calibrated automated thrombography: in vitro thrombin generation induced with 1 pM tissue factor in the presence of added procoagulant phospholipids. There were no differences between patients and controls regarding the ability of PMN to increase thrombin generation. More surprisingly, basal thrombin generation in acellular MPD-plasma was found decreased for as yet unknown reasons. The presence of an active protein C pathway or platelets might provide a better insight into the coagulation phenotype in MPD.
Blood Cells, Molecules, and Diseases.
