sepharose and Thrombosis

The increased demand for training of mechanical thrombectomy in ischemic stroke and development of new recanalization devices urges the creation of new simulation models both for training and device assessment. Clots properties have shown to play a role in procedural planning and thrombectomy device effectiveness. In this study, we analyzed the characteristics and applicability of completely synthetic, animal-free clots in the setting of an in-vitro model of mechanical thrombectomy for training and device assessment.. Synthetic clots based on agarose (n = 12) and silicone (n = 11) were evaluated in an in-vitro neurointervention simulation of mechanical thrombectomy with clot extraction devices. Calcified clots of mixed nature were simulated with addition of 3D printed structures. 9 clots were excluded due to insufficient vessel occlusion and failure to integrate with clot extraction device. Synthetic thrombi were characterized and compared using a categorical score-system on vessel occlusion, elasticity, fragmentation, adherence and device integration.. Both agarose-based and silicone-based clots demonstrated relevant flow arrest and a good integration with the clot extraction device. Silicone-based clots scored higher on adherence to the vessel wall and elasticity.. Selected synthetic clots can successfully be implemented in an in-vitro training environment of mechanical thrombectomy. The clots' different properties might serve to mimic fibrin-rich and red blood cell-rich human thrombi.

Topics: Humans; Sepharose; Silicones; Stroke; Thrombectomy; Thrombosis; Treatment Outcome

Arterial thrombosis is an important complication of diabetes and cancer, being an important target for therapeutic intervention. Crataeva tapia bark lectin (CrataBL) has been previously shown to have hypoglycemiant effect and also to induce cancer cell apoptosis. It also showed inhibitory activity against Factor Xa (Kiapp=8.6 μm). In the present study, we evaluated the anti-thrombotic properties of CrataBL in arterial thrombosis model. CrataBL prolongs the activated partial thromboplastin time on human and mouse plasma, and it impairs the heparin-induced potentiation of antithrombin III and heparin-induced platelet activation in the presence of low-dose ADP. It is likely that the dense track of positive charge on CrataBL surface competes with the heparin ability to bind to antithrombin III and to stimulate platelets. In the photochemically induced thrombosis model in mice, in the groups treated with 1.25, 5.0, or 10 mg/kg CrataBL, prior to the thrombus induction, the time of total artery occlusion was prolonged by 33.38%, 65%, and 66.11%, respectively, relative to the time of the control group. In contrast to heparin, the bleeding time in CrataBL-treated mice was no longer than in the control. In conclusion, CrataBL was effective in blocking coagulation and arterial thrombus formation, without increasing bleeding time.

Topics: Animals; Blood Coagulation; Capparaceae; Carotid Arteries; Chromatography, Affinity; Disease Models, Animal; Factor Xa Inhibitors; Humans; Hydrolysis; Mice, Inbred C57BL; Nitric Oxide; Partial Thromboplastin Time; Plant Lectins; Platelet Aggregation; Prothrombin Time; Regional Blood Flow; Sepharose; Substrate Specificity; Thrombosis

To assess the binding ability of microbubbles targeted to alphavbeta3-integrin (MBp) for thrombus-targeted contrast-enhanced ultrasound.. Targeted microbubbles were prepared by conjugating the monoclonal antibody against alphavbeta3-integrin to lipid shell of the microbubble via the avidin-biotin bridges. Equivalent isotype control microbubbles (MB) or targeted ultrasound microbubbles (MBp) were randomly added into the flow chamber. After a 30-min incubation with the thrombus fixed in an agarose flow chamber model, the thrombus was washed with a continuous flow of PBS solution (15 cm/s) for 2, 4, 6, 8 and 10 min, followed by thrombus imaging using contrast-enhanced ultrasound and measurement of the video intensity (VI) values of the images.. The VI of the thrombus in MBp group was reduced by 28%-66%, while that in control MB group was decreased by 87%-94%, and the VI values of the thrombus group were significantly greater in former group at each of the time points (P<0.05).. MBP has good targeting ability to the thrombus with resistance to the shear stress after adhesion to the thrombus. In vitro evaluation of the thrombus-binding capability of the targeted microbubble (MBp) by simulating the shear stress in vivo can be helpful for predicting the in vivo effects of ultrasonic molecular imaging using MBp.

Topics: Antibodies, Monoclonal; Contrast Media; Humans; Integrin alphaVbeta3; Microbubbles; Sepharose; Thrombosis; Ultrasonography

Classical genetic approaches to study hemostasis and thrombosis have not been available until our recent introduction of the teleost, Danio rerio (the zebrafish), as an effective genetic model for in vivo coagulation assays. The genetic screen for this model is carried out using the genome saturation mutagenesis approach. The resulting mutants are screened for hemostatic or thrombotic defects. We developed a global physiological screening method for thrombosis by utilizing a laser to induce thrombosis in a specifically targeted area of the major artery and vein. Using this assay, we have screened many fish for abnormal hemostasis, and have isolated a number of mutants with abnormal coagulation parameters. These mutants can be grown, bred, and further evaluated for the genetic etiology of their abnormal hemostatic pathways.

Topics: Animals; Blood Coagulation Disorders; Breeding; Hemostasis; Lasers; Models, Animal; Sepharose; Thrombosis; Zebrafish

Radioimmunotherapy using radiolabeled antitumor antibodies (RAA) is limited by the toxicity of unbound antibodies in the circulation. Removal of excessive antibodies by affinity-adsorption could therefore allow the administration of increased dosages of RAA while decreasing their adverse effects. Recently, avidin-agarose (AA) minicolumns were used in animal experiments for the removal of biotinylated antibodies from whole blood exploiting the high affinity binding of biotin to avidin (pK 1015 M-1). This study was performed to evaluate the ex vivo biocompatibility of AA minicolumns with human blood. Ten ml AA minicolumns were perfused online ex vivo in the single pass mode with fresh blood from 8 healthy donors at a flow rate of 6.25 ml/min. The anticoagulation consisted of 0.5 IU heparin plus 0.0-2.1 mg citrate per ml of blood. In Part 1 of the study (40 min perfusion, n = 4), the optimal anticoagulation was found to be 0.5 IU heparin plus about 1 mg citrate per ml of blood. In Part 2 of the study, four 80 min test-runs were performed. No signs of hemolysis were found, and the thrombogenicity of the AA gel was negligible. Cell counts and column inlet pressures remained constant; toward the end of the 80 min test-runs, some activation of blood cells (elastase, beta-thromboglobulin), the complement system (C3a, C5a) and the plasmatic coagulation (thrombin-antithrombin complex) was detectable. A moderate initial bradykinin release rapidly subsided to very low levels. In summary, AA minicolumns showed good biocompatibility upon contact with human whole blood and merit further investigation in a closed-loop system for a potential application of direct tumor antibody removal by hemoperfusion.

Topics: Adsorption; Antibodies; Antibodies, Neoplasm; Anticoagulants; Antithrombin III; Avidin; beta-Thromboglobulin; Biocompatible Materials; Biotin; Blood Cell Count; Bradykinin; Chromatography, Affinity; Citrates; Complement C3a; Complement C5a; Hemolysis; Hemoperfusion; Heparin; Humans; Ligands; Pancreatic Elastase; Peptide Hydrolases; Pressure; Radioimmunotherapy; Sepharose; Thrombosis

A 46-year-old female who died as a result of thrombocytopenia associated with multiple arterial occlusions and septicemia while on heparin therapy was found to have a platelet-aggregating factor present in several plasma samples and in a sample of serum. This factor was subsequently shown to be an IgG with aggregating properties toward normal platelets that were enhanced by, but not dependent on, the presence of heparin. Further studies showed that heparin was unlikely to have acted as a hapten in initiating the IgG production but that its role was significant in aggravating the ensuing arterial thrombosis. The necessity of substitution of heparin with alternative anticoagulant/antithrombotic therapy to avoid the worst sequelae of this potentially catastrophic syndrome is discussed.

Topics: Blood Coagulation Factors; Chromatography, Affinity; Female; Heparin; Humans; Immunoglobulin G; Middle Aged; Platelet Activating Factor; Platelet Aggregation; Sepharose; Thrombocytopenia; Thrombosis

Topics: Animals; Antithrombins; Chromatography, Affinity; Goats; Heparin; Humans; Partial Thromboplastin Time; Sepharose; Snakes; Thrombin Time; Thrombosis