Plasma Recalcification Time Research Articles

The antithrombotic, anticoagulant activity and toxicity research of ambinine, an alkaloid from the tuber of Corydalis ambigua var. amurensis

Ambinine, the major alkaloid of the tuber of Corydalis ambigua var. amurensis, has protective effects on H9C2 myocardial cells. In the present paper, we observed that ambinine demonstrates activities of both anticoagulation and thrombolysis in vitro by significantly degrading the blood clot and delaying the plasma recalcification time (PRT) in a dose-dependent manner (0.5–2 mg/mL). We further studied its safety profile of acute and subacute toxicity by repeated-dose intravenous injection. The median lethal dosage (LD50) of mice given by oral and intravenous administration of ambinine were approximate 800, 41.60 mg/kg, respectively. The acute toxicity research results suggested that compared with an intravenous administration, the oral route is safer to administer ambinine as the promising lead compound for thrombosis. In subacute toxicity research, when mice were given ambinine at doses of 1.40 and 2.10 mg/kg for 7 days by injection, significant alteration of the relative kidney weight, the relative liver weight and serum biochemistry parameters and marked histopathological changes of them were found.

Synthesis, characterization, molecular docking evaluation, antiplatelet and anticoagulant actions of 1,2,4 triazole hydrazone and sulphonamide novel derivatives

In the present study, a series of new hydrazone and sulfonamide derivatives of 1,2,4-triazole were synthesized. Initially three 4-substituted-5-(2-pyridyl)-1,2,4-triazole-3-thiones ZE-1(a–c) were treated with ethyl chloroacetate to get the corresponding thioesters ZE-2(a–c), which were reacted with hydrazine hydrate to the respective hydrazides ZE-3(a–c). The synthesized hydrazides were condensed with different aldehydes and p-toluene sulfonylchloride to furnish the target hydrazone derivatives ZE-4(a–c) and sulfonamide derivatives ZE-5(a–c) respectively. All the synthesized compounds were characterized by FTIR, 1HNMR, 13CNMR and elemental analysis data. Furthermore, the new hydrazone and sulfonamide derivatives ZE-4(b–c) and ZE-5(a–b) were evaluated for their antiplatelet and anticoagulant activities. ZE-4b, ZE-4c, ZE-5a and ZE-5b inhibited arachidonic acid, adenosine diphosphate and collagen-induced platelets aggregation with IC50 values of 40.1, 785 and 10.01 (ZE-4b), 55.3, 850.4 and 10 (ZE-4c), 121.6, 956.8 and 30.1 (ZE-5a), 99.9, 519 and 29.97 (ZE-5b) respectively. Test compounds increased plasma recalcification time (PRT) and bleeding time (BT) with ZE-4c being found most effective, which at 30, 100, 300 and 1000 µM increased PRT to 84.2 ± 1.88, 142 ± 3.51, 205.6 ± 5.37 and 300.2 ± 3.48 s and prolonged BT to 90.5 ± 3.12, 112.25 ± 2.66, 145.75 ± 1.60 s (P < 0.001 vs. saline group) respectively. In silico docking approach was also applied to screen these compounds for their efficacy against selected drug targets of platelet aggregation and blood coagulation. Thus in silico, in vitro and in vivo investigations of ZE-4b, ZE-4c, ZE-5a and ZE-5b prove their antiplatelet and anticoagulant potential and can be used as lead molecules for further development.

Anticoagulant polyurethane substrates modified with poly(2-methacryloyloxyethyl phosphorylcholine) via SI-RATRP.

A novel catalyst system of Reverse Atom Transfer Radical Polymerization (RATRP) to prepare Polyurethane (PU) films modified by poly(2-methacryloyloxyethyl phosphorylcholine) (pMPC) was studied in this article. In this system, PU film was pretreated by LaCl3/CA ethanol solution to obtain a hydrated surface allowing more initiators to be immobilized on it. Moreover, complexes composed of silane coupling agent 3-chloropropyltrimethoxysilane (CPTM), chlorhexidine acetate (CA) and lanthanum(III) worked as ligands of copper ions as a whole during RATRP process. PU films before and after modification were characterized by X-ray photoelectron spectroscopy (XPS) and static contact angle (SCA) to confirm that pMPC chains were successfully grafted from the substrates. Results of Plasma recalcification time assay, platelet adhesion test indicated excellent blood compatibility. Furthermore, the antibacterial activity of the material have been improved which proved by adhesion test of E.coil.

ПОКАЗНИКИ ГЕМОСТАТИЧНОГО ПОТЕНЦІАЛУ НА РІЗНИХ СТАДІЯХ РАКУ СЕЧОВОГО МІХУРА

Bladder cancer is characterized by a high mortality rate and is the 9th most common cancerous disease in the world. With a wide array of diagnostic bases, which include cystoscopy, ultrasound, computer and magnetic resonance imaging, cytology of urine deposition, it is difficult to accurately determine the extent of development of the tumor. It is important to find molecular and biochemical predictive parameters that would be characterized by high specificity and sensitivity to the tumor development. According to modern scientific data, an imbalance in the coagulation system is observed in cancer patients, the manifestation of which is the activation of the blood clotting system. Activation of the hemostatic system is accompanied by the appearance in the bloodstream of specific markers that reflect increase the hemostatic potential of the blood, such as the level of fibrin, fibrinogen, prothrombin time, activated partial thromboplastin time, activated plasma recalcification time. The results of a study of various cancers indicate an increased level of components of the plasminogen activation system, including the inhibitor of plasminogen activator-1 (PAI-1). The literature data that would indicate the prognostic significance of changes in the parameters of the blood clotting system and the proteolytic system in the blood in bladder cancer are few and have not completed. There are no data indicating the link between the studied parameters with histopathological gradation. In a detailed review of markers, it is possible to identify the optimal combination of markers of pathological processes, including the pathogenesis of oncological processes at various stages. During the study, we have investigated a significant increase in the level of fibrin, fibrinogen, and PAI-1, depending on the degree of bladder cancer. The test scores can make a significant contribution to the characterization of bladder cancer, depending on the grade according to the histopathological classification.

The in vitro and in vivo biocompatibility evaluation of electrospun recombinant spider silk protein/PCL/gelatin for small caliber vascular tissue engineering scaffolds

Recombinant spider silk protein (pNSR32) and gelatin (Gt) were demonstrated to enhance cytocompatibility of electrospun pNSR32/PCL/Gt scaffold. However, its potential pro-inflammatory effects and interactions with tissue and blood are unknown. In this study, the physicochemical properties and in vitro and in vivo biocompatibility of such scaffolds were evaluated. The results showed that the pNSR32/PCL/Gt scaffold possessed larger average fiber diameters, wider fiber diameter distribution and faster degradation rate than that of pNSR32/PCL and PCL scaffolds. The addition of pNSR32 and Gt had little influence on the hemolysis and plasma re-calcification time, but prolonged kinetic clotting time and reduced the platelet adhesion. The Il-6 and Tnf-α mRNA expression levels were up-regulated in macrophages seeded on the PCL and pNSR32/PCL scaffolds. The lowest release of IL-6 and TNF-α appeared in the pNSR32/PCL/Gt scaffold. Histological results revealed that the PCL and pNSR32/PCL scaffolds elicited severe host tissue responses after implantation, while prominent ingrowth of host cells were observed in the pNSR32/PCL and pNSR32/PCL/Gt scaffolds. The comet assay and bone marrow micronucleus test demonstrated that the pNSR32/PCL/Gt scaffold did not increase the frequency of DNA damage or bone marrow micronucleus. In short, this study confirmed that the pNSR32/PCL/Gt scaffold exhibited better blood and tissue compatibility than pNSR32/PCL and PCL scaffolds. No induction of genotoxicity and inflammatory factor releases makes the pNSR32/PCL/Gt scaffold a good candidate for engineering small diameter vascular tissue.

Evaluation of the antithrombotic activity of Zhi-Xiong Capsules, a Traditional Chinese Medicinal formula, via the pathway of anti-coagulation, anti-platelet activation and anti-fibrinolysis

Zhi-Xiong Capsules (ZXC) involving Hirudo, Ligusticum chuanxiong, Salvia miltiorrhiza, Leonurus artemisia, and Pueraria lobata, is an empirical prescription used in Chinese clinics applied for treating cerebral arteriosclerosis and blood-stasis in clinic. However, the mechanism of its antithrombotic activity has not been investigated until now. The present study was designed to investigate its antithrombotic effects, the mechanism of ZXC on anti-thrombus action and to identify the main chemical composition of ZXC using HPLC-DAD-ESI-IT-TOF-MS. Two animal models were used to evaluate the antithrombotic effect of ZXC, the arterial thrombosis model and a venous thrombosis model. ZXC prolonged the plasma recalcification time (PRT), the activated partial thromboplastin time (APTT), the thrombin time (TT) and the prothrombin time (PT) and clearly reduced the content of fibrinogen (FIB) obviously in the arterial thrombosis model. Furthermore, it markedly suppressed the level of TXB2 and up-regulated the level of 6-keto-PGF1a. In addition, it significantly up-regulated the level of t-PA and down-regulated the level of PAI-1 (p < 0.05). These results revealed that ZXC played a vital role in the prevention of thrombosis through interacting with multiple targets, including inhibition of coagulation and platelet aggregation and increasing thrombolysis. A total of 23 compounds were identified as the main components of ZXC by HPLC-DAD-ESI-IT TOF-MS.

Study on the Anticoagulant or Procoagulant Activities of Type II Phenolic Acid Derivatives.

In this study, three type II phenolic acids (caffeic acid, p-hydroxycinnamic acid, and ferulic acid) were used to synthesize a total of 18 phenolic acid derivatives. With molecular docking for molecule design and target protein (factors) screening, in combination with the confirmation of target proteins (factors) by surface plasmon resonance, and the evaluation of haemostatic and anticoagulant activities with five blood assays (plasma recalcification time, prothrombin time, activated partial thromboplastin time, fibrinogen, and thrombin time), the data indicated that caffeic acid derivatives showed certain anticoagulant or procoagulant activities and that two other series contained compounds with the best anticoagulant activities. Using Materials Studio analysis, particular functional groups that affect anticoagulant or procoagulant activities were revealed, and these conclusions can guide the discovery of compounds with better activities.

Blood Compatibility of ZrO₂ Particle Reinforced PEEK Coatings on Ti6Al4V Substrates.

Titanium (Ti) and its alloys are widely used in biomedical devices. As biomaterials, the blood compatibility of Ti and its alloys is important and needs to be further improved to provide better functionality. In this work, we studied the suitability of zirconia (ZrO2) particle reinforced poly-ether-ether-ketone (PEEK) coatings on Ti6Al4V substrates for blood-contacting implants. The wettability, surface roughness and elastic modulus of the coatings were examined. Blood compatibility tests were conducted by erythrocytes observation, hemolysis assay and clotting time of recalcified human plasma, to find out correlations between the microstructure of the ZrO2-filled PEEK composite coatings and their blood compatibilities. The results suggested that adding ZrO2 nanoparticles increased the surface roughness and improved the wettability and Derjaguin-Muller-Toporov (DMT) elastic modulus of PEEK coating. The PEEK composite matrix coated Ti6Al4V specimens did not cause any aggregation of erythrocytes, showing morphological normal shapes. The hemolysis rate (HR) values of the tested specimens were much less than 5% according to ISO 10993-4 standard. The values of plasma recalcification time (PRT) of the tested specimens varied with the increasing amount of ZrO2 nanoparticles. Based on the results obtained, 10 wt % ZrO2 particle reinforced PEEK coating has demonstrated an optimum blood compatibility, and can be considered as a candidate to improve the performance of existing PEEK based coatings on titanium substrates.

Blood coagulation system in chronic benzene poisoning via inhalation

Aim. To experimentally study the changes occurring in blood coagulation system in exposure to low-dose benzene. &#x0D; Methods. The experiment was performed on 36 rabbits by chronic exposure of the animals to benzene during 4 months on a daily basis 4 hours a day with 1 non-exposure day a week and a one-month recovery period after the end of exposure. The average poisoning concentration of benzene in the chambers was between 1240±82 mg/m3. The animals were divided into three groups: group 1 was exposed to gradually increasing concentration of benzene, group 2 - to fluctuating (intermittent) concentrations of benzene, group 3 included unexposed to benzene animals and was used as the control group. Overall blood clotting activity, blood clotting time, blood clot retraction, plasma recalcification time, plasma tolerance to heparin, prothrombin index, fibrinogen concentration, blood fibrinolytic activity were determined. &#x0D; Results. In a month after exposure blood clot retraction rates in groups 1 and 2 increased by 79.8 and 23.1% respectively. Plasma tolerance to heparin most significantly changed in animals from group 2 (by 15.4%). Prothrombin time increased by 11.4% in group 1 while in group 3 this parameter decreased by 0.4%. Prothrombin index in group 1 decreased by 4.3%, and in group 2 the changes were not statistically significant. Concentration of fibrinogen in the blood in group 1 had no significant changes and decreased by 4.2% while in group 2 it decreased by 10.4%. Fibrinolytic activity in group 1 and 2 decreased by 47.5 and 5.8% respectively. &#x0D; Conclusion. The studied benzene concentrations impair blood coagulation and anti-coagulation systems including two stages of hemostasis: 1st stage - from factor XII activation, 2nd stage - from prothrombin (factor II) activation.

Evaluation of hemostatic effect of polyelectrolyte complex-based dressings.

The aim of this work was to develop a polyelectrolyte complex-based hemostatic dressing made from chitosan and polygalacturonic acid. Porous dressings were fabricated by ultrasonication of chitosan and alginate solutions followed by freeze-drying. Since chitosan has inherent hemostatic properties, and polygalacturonic acid is anti-inflammatory in nature, it was desired to combine these two polymers to develop an effective hemostatic dressing, which may also promote wound healing. Porous structure of the bandages was observed using field-emission scanning electron microscope. Blood clotting behavior was studied using whole blood clotting assay. Plasma recalcification time, prothrombin time, and activated partial thromboplastin time were also determined to study the mechanism of clotting. The dressings were found to accelerate clotting rates and showed increased thrombin activity with an increase in chitosan concentration.

Bioactive zwitterionic polymer brushes grafted from silicon wafers via SI-ATRP for enhancement of antifouling properties and endothelial cell selectivity

Zwitterionic copolymers keep good resistance to platelet adhesion and nonspecific protein adsorption. In this study, A block copolymer brushes consisting of carboxybetaine methacrylate (CBMA) and glycidyl methacrylate (GMA) were grafted from silicon wafers via surface-initiated atom transfer radical polymerization, and then the Arg-Glu-Asp-Val (REDV) peptide was attached to the polymer brush via an reactive epoxy group of the P(GMA) unit to improve endothelial cells (ECs) selectivity. These modified surfaces were evaluated with scanning electron microscopy, atomic force microscopy, attenuated total reflectance-Fourier transform infrared spectra, X-ray photoelectron spectroscopy, and static water contact angle measurement. The results showed that REDV-modified zwitterionic brushes were successfully constructed on silicon wafers. The biocompatibility of the membrane was determined by plasma recalcification time assay and platelet adhesion test. The results showed that the modified substrate exhibited good blood compatibility. Moreover, the proliferation of ECs and smooth muscle cells onto the REDV-modified copolymer brushes were examined to demonstrate the synergistic effect of CBMA with antifouling property and REDV peptide with ECs selectivity. All assays showed that the silicon wafers displayed excellent EC selectivity after modification. In summary, REDV-modified zwitterionic brushes had great potential for cardiovascular stent implantation.

A PC–PU nanoparticle/PU/decellularized scaffold composite vascular patch: Synergistically optimized overall performance promotes endothelialization

Composite vascular patches have gained increasingly attention due to the limited availability of autologous patches (vascular graft materials made from the blood vessels of the same recipient), the lack of growth capability of nonautologous patches (vascular graft materials made from the blood vessels of a different donor) and the disadvantages of synthetic patches. In this study, we report a highly biocompatible phosphatidylcholine–polyurethane nanoparticle/polyurethane/decellularized scaffold composite vascular patch (PCVP). It was fabricated by a facile method − cosedimentation. Its in vitro blood and cell compatibility including hemolysis, plasma recalcification time, coagulation time, platelet adhesion and cytotoxicity was evaluated. The surface modified with phosphatidylcholine–polyurethane (PC–PU) nanoparticles exhibited the improved anticoagulation activity. The in vivo performance of the PCVP was investigated in a mouse model. The nanopatterned surface that resembled the concave-convex structure of the luminal surface of native blood vessels enhanced cell attachment, proliferation, migration and differentiation. The decellularized scaffold had the mechanical property similar to that of the targeted blood vessels, which could withstand in vivo dynamic blood pressure. The overall performance of the PCVP was synergistically optimized by each layer of the multilayer design. The patched artery remained patent and the formation of endothelial tissue − endothelialization was achieved 30days after the in vivo implantation in a mouse model.

Alkyl chitosan film-high strength, functional biomaterials.

Biofilm with strong tensile strength is a topic item in the area of tissue engineering, medicine engineering, and so forth. Here we introduced an alkyl chitosan film with strong tensile strength and its possibility for an absorbable anticoagulation material in vivo was tested in the series of blood test, such as dynamic coagulation time, plasma recalcification time and hemolysis. Alkyl chitosan film was a better biomaterial than traditional chitosan film in the anticoagulation, tissue compatibility and cell compatibility. The unique trait of alkyl chitosan film may be for its greater contact angle and hydrophobicity ability to reduce the adsorption capacity for the blood component and the activity of fibrinolytic enzymes, enhance the antibacterial capacity than chitosan film. Moreover, none of chitosan film or butyl chitosan film exhibited quick inflammation or other disadvantage and degraded quickly by implanted test. Therefore, Alkyl chitosan film is of prospective properties as an implantable, absorbable agent for tissue heals, and this material need further research. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 3034-3041, 2017.

A novel kind of polysulfone material with excellent biocompatibility modified by the sulfonated hydroxypropyl chitosan

In order to ameliorate the biocompatibility of polysulfone (PSf), sulfonated hydroxypropyl chitosan (SHPCS) was grafted from PSf membrane material by Schiff-Base reaction. The original and modified membranes were characterized by attenuated total reflectance-Fourier transform infrared spectroscope (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), water contact angle (WCA) measurement, tensile strength test and antibacterial test in vitro, and the results indicated that the PSf modified by SHPCS (PSf-SHPCS) was synthesized successfully, the hydrophilicity of PSf-SHPCS membrane was improved to a great extent, all the membranes possessed good stability in physiological condition and the PSf-SHPCS membrane had good antibacterial property. Protein adsorption, platelet adhesion, hemolysis assay, plasma recalcification time, activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and whole blood clotting time were executed to evaluate the hemocompatibility of membranes decorated by SHPCS, and the results demonstrated that the modified membrane had fine hemocompatibility.

Antithrombotic mechanism of polysaccharides in Blackberry (Rubus spp.) seeds

ABSTRACTThe blackberry seed was typically removed as a byproduct and waste from blackberry fruits for juices. Developing value-added utilization of berry seeds will significantly expand the market for berry products as well as improve benefit to berry producers. However, the research on blackberry seed is limited. The objective of this paper was to research antithrombotic mechanism of polysaccharides in blackberry seeds. Polysaccharides in blackberry seeds were extracted, purified and identified by high-performance gel permeation chromatography (HPSEC), gas chromatography (GC), fourier transform infrared (FT-IR) spectrometer and nuclear magnetic resonance spectra (NMR). Anticoagulant activities were evaluated in vivo by measuring activated partial thromboplastin time (APTT), thrombin time (TT), prothrombin time (PT), fibrinogen (FIB) and plasma recalcification time (RRT). Four polysaccharides named BSP-1a, BSP-1b, BSP-2 and BSP-3 were isolated from Blackberry (Rubus spp.) seeds. The results indicated that BSP-1b, BSP-2 and BSP-3 exhibited the anticoagulant activity. Therefore, the anti-thrombosis effects of BSP-1b, BSP-2 and BSP-3 were investigated in vivo by 6-Keto-PGF1α, thromboxane B2 (TXB2), endothelial nitric oxide synthase (eNOS), endothelin-1 (ET-1), whole blood viscosity (WBV), plasma viscosity (PV), hematocrit (Hct), erythrocyte sedimentation rate (ESR), APTT, TT, PT and FIB. The results suggested that BSP-1b, BSP-2 and BSP-3 had the inhibition effect on thrombus formation, and the antithrombotic effects were associated with the regulation of vascular endothelium active substance, activating blood flow and anticoagulation effect.

Synthesis of Biodegradable and Blood-Compatible Polyurethane Based on Poly(vinylpyrrolidone)

Three kinds of degradable and blood-compatible polyurethane (PU) were synthesized by coupling hydroxyl-terminated poly(vinylpyrrolidone) (PVP) with diisocyanate-terminated PU. The chemical structure and molecular weight of the synthesized copolymer were systematically characterized by nuclear magnetic resonance spectrum (1HNMR), Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The hydrophilicity and water absorption of the synthesized PU was increased by introducing PVP segment. To evaluate the hemocompatibility and degradability of the modified PU films, the extent of platelet adsorption, plasma recalcification time, hemolysis and degradation were measured. All results indicated that the blood compatibility and degradability of the PU films were improved significantly after introduction PVP segment into PU.

Dual functionalized poly(vinylidene fluoride) membrane with acryloylmorpholine and argatroban to improve antifouling and hemocompatibility.

The present work aims to improve the antifouling properties and anticoagulation of poly(vinylidene fluoride) (PVDF) membrane by dual modification. An amphiphilic copolymer of PVDF-g-(polyacryloylmorpholine-(polyacrylic acid)) [PVDF-g-(PACMO-PAA)] was first prepared by the free radical copolymerization. Then argatroban, a commonly used anticoagulant, was successfully grafted to PVDF-g-(PACMO-PAA). Finally the obtained copolymer was casted into a flat membrane via immersion phase inversion. The as-prepared copolymer membranes show improved hydrophilicity, higher water flux and lower protein adsorption. Moreover, the hemolysis and coagulation tests for the dual functionalized PVDF membrane exhibit decreased hemolysis ratio, with prolonged plasma recalcification time, activated partial thromboplastin time and thrombin time. PVDF membrane incorporating PACMO and AG reveals an improved hemocompatibility, which has a good potential to be used in blood purification. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 178-188, 2017.

In vitro and in vivo hemocompatibility evaluation of a new dermatan sulfate-modified PET patch for vascular repair surgery.

The development of new vascular devices requires to study the effects of materials on blood cells and on coagulation, both in vitro and in vivo. In this study, we have developed a new material by grafting dermatan sulfate (DS) from shark skin onto polyethylene terephthalate (PET). We have evaluated the haemocompatibility of PET-DS material in vitro by measuring thrombin generation, plasma recalcification time, hemolytic activity, and platelet adhesion and in vivo with a model of vascular patch in rat abdominal aorta. In vitro, our results have shown that PET-DS is a nonhemolytic material, able to inhibit thrombin generation and platelet adhesion. In vivo studies by Doppler echographic evaluation 20 days after implantation have shown that the PET-DS patch was integrated in the vessel wall and covered by a layer of cells. In conclusion, PET-DS has good haemocompatibility properties and could be a promising tool for vascular surgery. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2001-2009, 2017.

ALD mediated heparin grafting on nitinol for self-expanded carotid stents

Carotid-artery atherosclerosis is a common cause of ischemic stroke. Carotid-artery stenting (CAS) is one of the most effective treatments. However, In-stent restenosis (ISR) and re-endothelialization delay are two major issues of intravascular stent which affect clinical safety and reduce effects. In this study, atomic layer deposition (ALD) technology was applied to deposit a layer (10nm) of Al2O3 on Nitinol surface as an intermediate functional layer. The alumina covered surface was then modified with a coupling agent 3-aminopropyltriethoxysilane (APS) and heparin sequentially in order to improve the hemocompatibility of Nitinol stents. The successful graft of APS and heparin onto Nitinol was proven by X-ray photoelectron spectroscopy. Furthermore, the predicted improvement in the biocompatibilities of modified Nitinol was confirmed by water contact angle measurement, protein adsorption, platelet adhesion, and plasma recalcification time determination. The results of hemolysis assay, cell proliferation and cytotoxicity tests revealed that the grafting of heparin on NiTi kept the original positive performance of nitinol material. The results indicate that ALD technology is of great potential for the manufacture of medical devices, especially for surface modifications and functionalization. ALD technology can help with modifications of inert metallic surfaces and therefore benefit implantable medical devices, especially intravascular stents.

Acute Common Iliac Artery Thrombosis with Concurrent Pulmonary Embolism Revealing AML M2: Role of Elevated Plasma Tissue Factor Activity

Background: Cancer patients are exposed to an increased risk of thrombohemorrhagic events. Whereas patients with solid tumors are prone to venous thromboembolism, acute leukemia may cause coagulopathy associated with thrombocytopenia leading to life-threatening bleeding. Disordered coagulatory system is predominant in AML M3 and to a lesser extent in hyperleukocytic AML M4 and M5. Thromboembolic events are rare in the context of unrecognized AML. Risk factors for arterial thrombosis in AML are not well described. Tissue Factor (TF) is being increasingly acknowledged as an important player in cancer thrombosis. We report a case of non-hyperleukocytic AML M2 revealed by an arterial occlusion with concurrent pulmonary embolism (PE) highlighting the potential role of elevated plasma TF activity as a precipitating event and a risk factor for thrombosis.Clinical Case: A 67-year-old non-smoker patient presented to emergency department because of a 6-hour history of pain in the right lower limb with pallor and coolness. Pulses were abolished in all arteries of the right lower limb without any sensory loss or motor deficit. Contralateral pulses were normal. Clinical examination was otherwise normal. She had no history of intermittent claudication. Past medical history was remarkable for hypertension, thyroid disease and obesity treated two years ago by a gastric bypass surgery complicated by a first episode of PE treated by low molecular weight heparin (LMWH). No further testing for thrombophilia was performed at that time.A total occlusion of the right common and external iliac arteries was confirmed by a CT-scan angiography. The distal arterial tree was healthy. A chest X-ray found bilateral condensations. A helical CT-scan of the chest disclosed bilateral PE with pulmonary infarction. A lung ventilation/perfusion scan confirmed PE. A transthoracic echocardiography found no intracavitary thrombus nor patent foramen ovale.Laboratory values were hemoglobin 9.8 g/dl, WBC 13.8 × 103 µl-1, platelets 60 × 103 µl-1, 80% blasts in the peripheral blood smear. Routine coagulation tests were within usual values (UV).Bone marrow (BM) aspiration found AML M2, myeloblasts were 80% with a cup-like nuclear morphology. Immunophenotyping of BM blasts disclosed CD34 and HLA-DR negativity. The karyotype was normal. Molecular evaluation found NPM1 gene mutation and FLT3 gene internal tandem duplication (FLT3-ITD). Jak2 gene was not mutated.Treatment consisted in LMWH followed by standard induction chemotherapy. Complete remission was achieved after induction followed by 2 courses of consolidation. Of note, the patient still suffers from intermittent claudication of the right leg.Extensive testing for thrombophilia excluded antithrombin, protein C, protein S and protein Z deficiencies, factor II and factor V mutations and antiphospholipid antibody syndrome. Homocysteinemia was normal. Procoagulant activity of intact blasts evaluated by a one-step plasma recalcification time assay was normal. Plasma TF activity was quantified by a one-stage kinetic chromogenic assay. Briefly, this assay is based on the ability of plasma TF to bind to FVIIa and on the capacity of the TF-FVIIa complex to generate FXa. At diagnosis TF activity was elevated at 2.92 pmol (UV<0.45). After remission it returned to normal.Discussion: To the best of our knowledge this is the first report of concurrent arterial and venous thromboses at presentation of AML. Classical risk factors for thrombosis in AML include coagulopathy and hyperleukocytosis yet neither were present here. Laboratory work-up for thrombophilia was negative. The only abnormal finding was an elevated plasma TF activity before chemotherapy. Interestingly, procoagulant activity on circulating blasts was normal, suggesting TF might have been generated from other sources than AML cells such as activated endothelium and/or normal white blood cells (monocytes, polynuclear neutrophils). TF activity returned to baseline after remission, strongly suggesting it was AML-associated either directly or via innate immunity.Conclusion: We report a case of non-hyperleukocytic AML M2 with an unusual presentation including an occlusion of a large artery with concurrent PE. TF activity could be considered in the future as a risk factor for arterial and/or venous thrombosis in AML independently of classical conditions such as hyperleukocytosis and coagulopathy. DisclosuresVan Dreden:Diagnostica Stago: Employment.