Ismail Elalamy

Tissue factor over-expression by human pancreatic cancer cells BXPC3 is related to higher prothrombotic potential as compared to breast cancer cells MCF7

Cancer histology influences the risk of venous thromboembolism and tissue factor (TF) is the key molecule in cancer-induced hypercoagulability. We investigated the relation between TF expression by pancreatic and breast cancer cells (BXPC3 and MCF7 respectively) and their capacity to trigger in vitro thrombin generation in normal human plasma. Flow cytometry and Western blot analysis for TF expression were performed using murine IgG1 monoclonal antibody against human TF. Real-time PCR for TFmRNA was also performed. Activity of TF expressed by cancer cells was measured with a specific chromogenic assay. Thrombin generation in PPP was assessed using calibrated automated thrombogram. Cancer cells were added to platelet poor plasma from healthy volunteers. In separate experiments cells were incubated with the anti-TF antibody at concentration that completely neutralized the activity of recombinant human TF on thrombin generation. BXPC3 cells expressed significantly higher amounts of functional TF as compared to MCF7 cells. Incubation of BXPC3 and MCF7 cells with PPP resulted in acceleration of the initiation phase of thrombin generation. BXPC3 cells manifested higher procoagulant potential than MCF7 cells. The incubation of BXPC3 or MCF7 cells with the anti-TF monoclonal antibody which resulted in reversal of their effect on thrombin generation. The present study establishes a link between the amount of TF expressed by cancer cells with their procoagulant activity. Both studied types of cancer cells trigger thrombin generation but they have different procoagulant potential. The procoagulant activity of BXPC3 and MCF7 cells is related to the amount of TF expressed. Kinetic parameters of thrombogram are the most relevant for the detection of the TF-dependent procoagulant activity of cancer cells. TF expression is one of the mechanisms by which cancer cells manifest their procoagulant potential but it is not the unique one. The present experimental model will allow the characterization the procoagulant fingerprint of cell lines from the same or different histological types of cancer.

Prevention and Treatment of Venous Thromboembolism International Consensus Statement (Guidelines according to scientific evidence)

All patients at moderate to high risk for the development of venous thrombo- embolism should receive prophylaxis. The approaches of proven value include low-dose heparin, low molecular weight heparin, oral anticoagulants and intermittent pneumatic compression.

Impact of breast cancer stage, time from diagnosis and chemotherapy on plasma and cellular biomarkers of hypercoagulability

BackgroundIn breast cancer patients routine thromboprophylaxis is not recommended but individualized risk assessment is encouraged. The incorporation of hypercoagulability biomarkers could increase the sensitivity of risk assessment models (RAM) to identify patients at VTE risk. To this aim we investigated the impact of cancer-related characteristics on hypercoagulability biomarkers.MethodsThrombin generation (TG) assessed with the Thrombogramme-Thrombinoscope®, levels of platelet derived microparticles (Pd-MP) assessed with flow cytometry, procoagulant phospholid dependent clotting time (PPL-ct) measured with a clotting assay and D-Dimers (were assessed in a cohort of 62 women with breast cancer and in 30 age matched healthy women.ResultsPatients showed significantly higher TG, Pd-MP, D-Dimers levels and shortened PPL-ct compared to the controls. The PPL-ct was inversely correlated with the levels of Pd-MP, which were increased in 97% of patients. TG and D-Dimers were increased in 76% and 59% of patients respectively. In any stage of the disease TG was significantly increased as compared to the controls. There was no significant difference of TG in patients with local, regional of metastatic stage. There was no significant difference in Pd-MP or Pd-MP/PS+ between the subgroups of patients with local or regional stage of cancer. Patients with metastatic disease had significantly higher levels of Pd-MP and Pd-MP/PS+ compared to those with regional stage. The D-Dimers increased in patients with metastatic stage. In patients on chemotherapy with less than 6 months since diagnosis TG was significantly higher compared to those on chemotherapy who diagnosed in interval > 6 months. Patients with metastatic disease had significantly higher levels of Pd-MP and D-Dimers compared to those with non-metastatic disease.ConclusionIn breast cancer patients the stage, the time elapsed since the diagnosis and the administration of chemotherapy are determinants of cellular and plasma hypercoagulability. The levels and the procoagulant activity of Pd-MP are interconnected with the biological activity and the overall burden of cancer. TG reflects the procoagulant properties of both breast cancer and chemotherapy in the initial period of cancer diagnosis. Thus the weighted incorporation of the biomarkers of cellular and plasma hypercoagulabilty in RAM for VTE might improve their predictive value.

Lobectomy and postoperative thromboprophylaxis with enoxaparin improve blood hypercoagulability in patients with localized primary lung adenocarcinoma

BACKGROUND Patients with lung adenocarcinoma undergoing surgery are in high risk for VTE and receive routine post-operative thromboprophylaxis with LWMH. AIM We investigated markers of hypercoagulability in patients with primary localized adenocarcinoma and the modifications induced by lobectomy and postoperative administration of enoxaparin. MATERIALS AND METHODS Patients suffering from localised primary lung adenocarcinoma (n=15) scheduled for lobectomy were studied. The control group consisted of 15 healthy age and sex-matched individuals. Blood was collected before anaesthesia induction and after surgery, at several intervals until the 7th post-operative day. Samples were assessed for thrombin generation, phosphatidylserin expressing platelet derived microparticles expressing (Pd-MP/PS(+)), tissue factor activity (TFa), FVIIa and TFPI levels, procoagulant phospholipid dependent clotting time and anti-Xa activity. RESULTS At baseline, patients showed increased thrombin generation and Pd-MP/PS(+). After lobectomy thrombin generation significantly decreased. Administration of enoxaparin attenuated thrombin generation. In about 50% of samples collected post-operatively an increase of thrombin generation occurred despite the presence of the expected anti-Xa activity in plasma. At the 7th post-operative day, 3 out of 15 patients showed a significant increase of thrombin generation. CONCLUSION In patients with localized lung adenocarcinoma, hypercoagulability is characterized by high thrombin generation and increased concentration of Pd-MP/PS(+). Tumor mass resection is related with attenuation of thrombin generation, which is inhibited by postoperative thromboprophylaxis with enoxaparin. The response to enoxaparin is not predicted by the concentration of the anti-Xa activity in plasma. The assessment of thrombin generation during prophylaxis with enoxaparin allows to identify patients with high residual plasma hypercoagulability.

Diagnosis and Anticoagulant Treatment

2012;97(1):95-100. 64. Brill-Edwards P, Ginsberg JS, Gent M, et al. Safety of withholding heparin in pregnant women with a history of venous thromboembolism. Recurrence of clot in this pregnancy study group. N Engl J Med. 2000;343(20):1439-1444. 65. De Stefano V, Martinelli I, Rossi E, et al. The risk of recurrent venous thromboembolism in pregnancy and puerperium without antithrombotic prophylaxis. Br J Haematol. 2006;135(3):386-391. 66. White RH, Chan WS, Zhou H, Ginsberg JS. Recurrent venous thromboembolism after pregnancy-associated versus unprovoked thromboembolism. Thromb Haemost. 2008;100(2):246-252. 67. Pabinger I, Schneider B. Thrombotic risk in hereditary antithrombin III, protein C, or protein S deficiency. A cooperative, retrospective study. Gesellschaft fur Thromboseund Hamostaseforschung (GTH) Study Group on Natural Inhibitors. Arterioscler Thromb Vasc Biol. 1996;16(6):742-748. 68. Conard J, Horellou MH, Van Dreden P, Lecompte T, Samama M. Thrombosis and pregnancy in congenital deficiencies in AT III, protein C or protein S: study of 78 women. Thromb Haemost. 1990;63(2):319-320. 69. McColl MD, Ramsay JE, Tait RC, et al. Risk factors for pregnancy associated venous thromboembolism. Thromb Haemost. 1997;78(4):1183-1188. 70. Robertson L, Wu O, Langhorne P, et al. Thrombophilia in pregnancy: a systematic review. Br J Haematol. 2006;132(2):171-196. 71. Serour GI, Aboulghar M, Mansour R, Sattar MA, Amin Y, Aboulghar H. Complications of medically assisted conception in 3,500 cycles. Fertil Steril. 1998;70(4):638-642. 72. Mara M, Koryntova D, Rezabek K, et al. Thromboembolic complications in patients undergoing in vitro fertilization: retrospective clinical study. Ceska Gynekol. 2004;69(4):312-316. 73. Chan WS, Dixon ME. The ‘‘ART’’ of thromboembolism: a review of assisted reproductive technology and thromboembolic complications. Thromb Res. 2008;121(6):713-726. 74. Di Nisio M, Rutjes AW, Ferrante N, Tiboni GM, Cuccurullo F, Porreca E. Thrombophilia and outcomes of assisted reproduction technologies: a systematic review and meta-analysis. Blood. 2011;118(10):2670-2678. 75. Nelson-Piercy C, Powrie R, Borg JY, et al. Tinzaparin use in pregnancy: an international, retrospective study of the safety and efficacy profile. Eur J Obstet Gynecol Reprod Biol. 2011;159(2): 293-299. 76. Byrd LM, Shiach CR, Hay CR, Johnston TA. Osteopenic fractures in pregnancy: is low molecular weight heparin (LMWH) implicated? J Obstet Gynaecol. 2008;28(5):539-542. 77. Hellgren M, Tengborn L, Abildgaard U. Pregnancy in women with congenital antithrombin III deficiency: experience of treatment with heparin and antithrombin. Gynecol Obstet Invest. 1982;14(2):127-141. 78. Tiede A, Tait RC, Shaffer DW, et al. Antithrombin alfa in hereditary antithrombin deficient patients: a phase 3 study of prophylactic intravenous administration in high risk situations. Thromb Haemost. 2008;99(3):616-622. 79. Pernod G, Biron-Andreani C, Morange PE, et al. Recommendations on testing for thrombophilia in venous thromboembolic disease: a French consensus guideline. J Mal Vasc. 2009;34(3): 156-203. 80. Baglin T, Gray E, Greaves M, et al. Clinical guidelines for testing for heritable thrombophilia. Br J Haematol. 2010;149(2): 209-220. 81. Kearon C. Influence of hereditary or acquired thrombophilias on the treatment of venous thromboembolism. Curr Opin Hematol. 2012;19(5):363-370. 82. Jenkins PV, Rawley O, Smith OP, O’Donnell JS. Elevated factor VIII levels and risk of venous thrombosis. Br J Haematol. 2008; 157(6):653-663.

The study of the thrombin generation mechanism and the effect of low molecular weight heparin as thromboprophylaxis in patients undergoing total knee and hip replacement

INTRODUCTION The recommended duration of post-operative Low-Molecular-Weight-Heparins (LMWHs) thromboprophylaxis in Total-Hip-Replacement (THR) and Total-Knee-Replacement (TKR) surgery is controversial. Our aim is to study the thrombin generation (TG) modifications induced by surgery and to evaluate the effect of LMWH on TG during and after the recommended duration. PATIENTS/METHODS Thirty-one patients received 4000IU anti-Xa/day of enoxaparin, 8-hours post-operatively (15 THR for 30-days and 16 TKR for 15-days). TG assay sensitive to enoxaparin was performed, pre-operatively (D0), 7-hours post-surgery (D1), 8-days post-surgery (D8), and 2-days after thromboprophylaxis withdrawal (D32 and D17), evaluating: lag-time, endogenous thrombin potential (ETP), peak amount of generated thrombin (Peak), time-to-Peak (tt-Peak), and the Mean-Rate-Index [MRI=Peak/(tt-Peak-lag-time)]. RESULTS TKR surgery decreased lag-time and tt-Peak and increased MRI on D1 vs D0 (p<0.05). In contrast, THR did not significantly modify TG. Enoxaparin effectively reduced thrombin generation in both groups. Thromboprophylaxis withdrawal resulted in rebound increase of TG in the TKR patients (ETP, Peak & MRI significantly increased on D17 vs D0; p<0.05, and vs. D1; p<0.05) but not in THR patients. Variability in the response to enoxaparin was observed among patients of the same group. CONCLUSIONS TKR surgery is more thrombogenic than THR surgery. In THR patients TG was efficiently inhibited by 30-day thromboprophylaxis, whereas, in TKR patients treated for 15-days TG was not effectively inhibited. Individual variability of the response to enoxaparin was observed in both groups revealing some form of biological resistance to enoxaparin. TG assay may represent the breakthrough step to efficient antithrombotic strategy in clinical settings with high thrombotic risk.

Cancer cells BXPC3 and MCF7 differentially reverse the inhibition of thrombin generation by apixaban, fondaparinux and enoxaparin.

INTRODUCTION Cancer cells may alter the efficiency of the antithrombotic agents. To explore this possibility, the present study compared the capacity of the LMWH enoxaparin and the specific inhibitors of Xa (apixaban and fondaparinux) to inhibit thrombin generation triggered by pancreas adenocarcinoma cells (BXPC3) and human breast carcinoma cells (MCF7). MATERIALS AND METHODS Samples of platelet poor (PPP) or platelet rich plasma (PRP) spiked with apixaban, fondaparinux or enoxaparin were added in micro wells carrying cancer cells and assessed for thrombin generation. In the control experiment thrombin generation was triggered with tissue factor reagent. RESULTS The three antithrombotics inhibited thrombin generation in a concentration dependent manner. The BXPC3 and MCF7 cells reversed in a different intensity the effect of the studied agents. According to the histological type of the cancer the antithrombotic efficiency of apixaban was preserved or partially reversed. Fondaparinux, was more vulnerable to the presence of cancer cells as compared to apixaban. The effect of BXCP3 or MCF7 cells on the antithrombotic potency of enoxaparin was of similar magnitude as that on apixaban. CONCLUSIONS The type of cancer cells is determinant for the antithrombotic efficiency of the specific factor Xa inhibitors. In contrast it does not significantly influence the potency of enoxaparin. The present study shows that the impact of the type of cancer cells on the antithrombotic activity of the specific Xa inhibitors should not be neglected. This has to be taken into consideration for the design of dose-finding studies of the direct orally active FXa inhibitors in patients with different histological types of cancer.

Prevention of postthrombotic syndrome.

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Cost-Effectiveness of Prevention and Treatment of VTE

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Periprocedural bridging therapy with low-molecular-weight heparin in chronically anticoagulated patients with prosthetic mechanical heart valves: experience in 116 patients from the prospective BRAVE registry. J Heart Valve Disease. 2007;16(3):285-292. 32. Pengo V, Cucchini U, Denas G, et al. Standardized lowmolecular-weight heparin bridging regimen in outpatients on oral anticoagulants undergoing invasive procedure or surgery: an inception cohort management study. Circulation. 2009; 119(22):2920-2927. 33. Katholi RE, Nolan SP, McGuire LB. The management of anticoagulation during noncardiac operations in patients with prosthetic heart valves. A prospective study. Am Heart J. 1978;96(2):163-165. 34. Spyropoulos AC, Turpie AG, Dunn AS, et al. Clinical outcomes with unfractionated heparin or low-molecular-weight heparin as bridging therapy in patients on long-term oral anticoagulants: the REGIMEN registry. J Thromb Haemost. 2006; 4(6):1246-1252. 35. Garcia DA, Regan S, Henault LE, et al. Risk of thromboembolism with short-term interruption of warfarin therapy [see comment]. Arch Intern Med. 2008;168(1):63-69. 36. Malato AAR, Cigna V, Sciacca M, Abbene I, Saccullo G, Lo Cocco L, Siragusa S. Perioperative bridging therapy with low molecular weight heparin in patients requiring interruption of long-term oral anticoagulant therapy. Haematologica. 2006;91:10. 37. Hammerstingl C, Omran H. Bridging of oral anticoagulation with low-molecular-weight heparin: experience in 373 patients with renal insufficiency undergoing invasive procedures. Thromb Haemost. 2009;101(6):1085-1090. 38. Jaffer AK, Ahmed M, Brotman DJ, et al. Low-molecular-weightheparins as periprocedural anticoagulation for patients on longterm warfarin therapy: a standardized bridging therapy protocol. J Thromb Thrombolysis. 2005;20(1):11-16. 39. Spyropoulos AC. Bridging therapy and oral anticoagulation: current and future prospects. 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General, vascular, bariatric, and plastic surgical patients.

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