Changes In Procoagulant Activity Research Articles

Changes in procoagulant activity during pregnancy in women with drug addiction

Objective: to study hemostatic features of procoagulant link in pregnant women with drug addiction.Materials and methods. 156 pregnant women were examined: 96 women with drug addiction (main group) and 60 pregnant women in control group. All patients tests for hemostatic system by avaluation of total fibrinogen, prothrombin by Quick, activated partial thromboplastin time, and the mother-placenta-fetus system state. Ultrasound (Doppler ultrasound) was performed to estimate of fetoplacental complex.Results. Shifts of coagulation system to the hypercoagulation state in women with drug addiction were noted, it was manifested by an increase in fibrinogen, prothrombin by Quick and a decrease in activated partial thromboplastin time. Significant difference in these indicators was revealed in drug-dependent pregnant women compared with the control group (p <0.05). There were also changes in the mother-placenta-fetus system with doppler ultrasound, which manifested by a clinically significant deterioration in blood flow in the uterine arteries (p <0.05).Conclusions. The course of pregnancy in women with drug addiction is characterized by the development of a hypercoagulable state. It causes thrombosis, diapedetic hemorrhage. This condition without correction subsequently leads to bleeding, as a result of intrauterine growth retardation, antenatal fetus death in the worst case.Pregnant with drug addiction in the third trimester characterized hypercoagulation state, that is as indicated by an increase in fibrinogen, prothrombin by Quick and shortening of the activated partial thromboplastin time in comparison with pregnant women in the control group. A high proportion of gestational and perinatal complications was revealed in women of the main group (placental structural changes, hemodynamic disturbances of the second and third stages in the mother-placenta-fetus system and fetal growth retardation).

Carbonic Anhydrase Inhibitors suppress platelet procoagulant responses and in vivo thrombosis

Carbonic anhydrase (CA) inhibitors have a long history of safe clinical use as mild diuretics, in the treatment of glaucoma and for altitude sickness prevention. In this study, we aimed to determine if CA inhibition may be an alternative approach to control thrombosis. We utilized a high-resolution dynamic imaging approach to provide mechanistic evidence that CA inhibitors may be potent anti-procoagulant agents in vitro and effective anti-thrombotics in vivo. Acetazolamide and methazolamide, while sparing platelet secretion, attenuated intracellular chloride ion entry and suppressed the procoagulant response of activated platelets in vitro and thrombosis in vivo. The chemically similar N-methyl acetazolamide, which lacks CA inhibitory activity, did not affect platelet procoagulant response in vitro. Outputs from rotational thromboelastometry did not reflect changes in procoagulant activity and reveal the need for a suitable clinical test for procoagulant activity. Drugs specifically targeting procoagulant remodeling of activated platelets, by blockade of carbonic anhydrases, may provide a new way to control platelet-driven thrombosis without blocking essential platelet secretion responses.

Low-Dose Epinephrine Infusions and Tranexamic Acid During Lower-Extremity Total Joint Arthroplasty: Commentary on an article by Wei-Nan Zeng, MD, et al.: "Low-Dose Epinephrine Plus Tranexamic Acid Reduces Early Postoperative Blood Loss and Inflammatory Response. A Randomized Controlled Trial".

Low-Dose Epinephrine Infusions and Tranexamic Acid During Lower-Extremity Total Joint Arthroplasty: Commentary on an article by Wei-Nan Zeng, MD, et al.: "Low-Dose Epinephrine Plus Tranexamic Acid Reduces Early Postoperative Blood Loss and Inflammatory Response. A Randomized Controlled Trial".

Cell-based evaluation of changes in coagulation activity induced by antineoplastic drugs for the treatment of acute myeloid leukemia.

Idarubicin (IDR), cytarabine (AraC), and tamibarotene (Am80) are effective for treatment of acute myeloid leukemia (AML). In acute leukemia, the incidence of venous thromboembolism or disseminated intravascular coagulation is associated with induction chemotherapy. Procoagulant effects of IDR, AraC, and Am80 were investigated in a vascular endothelial cell line EAhy926 and AML cell lines HL60 (AML M2), NB4 (AML M3, APL), and U937 (AML M5), focusing on tissue factor (TF), phosphatidylserine (PS), and thrombomodulin (TM). IDR induced procoagulant activity on the surface of vascular endothelial and AML cell lines. Expression of TF antigen, TM antigen, and PS were induced by IDR on the surface of each cell line, whereas expression of TF and TM mRNAs were unchanged. Conversely, Am80 decreased TF exposure and procoagulant activity, and increased TM exposure on NB4 cells. In NB4 cells, we observed downregulation of TF mRNA and upregulation of TM mRNA. These data suggest IDR may induce procoagulant activity in vessels by apoptosis through PS exposure and/or TF expression on vascular endothelial and AML cell lines. Am80 may suppress blood coagulation through downregulation of TF expression and induction of TM expression. Our methods could be useful to investigate changes in procoagulant activity induced by antineoplastic drugs.

Procoagulant activity in stored units of red blood cells

The procoagulant activity (PA) of stored units of red blood cells (RBC) increases over time, which is related to the expression/exposure of tissue factor (TF). However, there is a discrepancy between the TF measured and changes in PA observed, suggesting that other blood components contribute to this activity. Our goal was to evaluate changes in PA of stored RBCs and to determine possible contributors to it. RBC units from 4 healthy donors were prepared and stored at 4 °C. On selected days, RBC aliquots were reconstituted with autologous plasma and tested in the thromboelastography assay. Corresponding supernatants were tested in a clotting assay. For all donors, the clotting time (CT) of reconstituted RBC units decreased from ∼3000–4000s on day 1 to ∼1000–1600s on day 30, with the most dramatic changes occurring between days 1 and 5. Anti-TF antibody slightly prolonged the CT. The concentration of TF did not change significantly over time and was within the range of 0.3–2.3 pM. Bovine lactadherin (LTD) prolonged the CT of the RBC (by 2.4–3.4-fold in days 3–5 and by 1.3–1.8-fold at day 30). Anti-TF antibody together with LTD had a cumulative effect on the CT prolongation. CT of supernatants responded to both anti-TF and anti-FXIa antibodies. Three contributors to the PA of stored RBC were identified, i.e. FXIa in solution and phosphatidylserine and TF exposed on blood cells and microparticles. Failure of LTD and antibodies to completely eliminate PA suggests that other components of blood could contribute to it.

Procoagulant Activity In Stored Units Of Red Blood Cells

It has been observed that the procoagulant activity of stored units of red blood cells (RBC) increases over time, which is, in part, related to the expression/exposure of tissue factor (TF) on blood cells and microparticles (Keating et al, Transfusion 2011;51:1086). However, in many instances there is a discrepancy between the levels of TF measured in stored units of RBC and changes in procoagulant activity observed over the storage time. We hypothesized that, in addition to TF, an exposure of an acidic phospholipid, phosphatidylserine (PS), on blood cells (Whelihan et al, Blood 2012;120:3837), could be the cause of an elevated procoagulant activity.Four healthy donors were recruited. RBC units were prepared and stored at 4°C for 30 days. On selected days, aliquots were removed, reconstituted with autologous plasma and recalcified, and were tested in the presence of corn trypsin inhibitor in the thromboelastography assay for procoagulant activity. For all 4 donors, the clotting time decreased from ∼3000-4000 s on day 1 to ∼1000-1600 s on day 30, with the most dramatic changes occurring between days 1 and 10. Addition of an inhibitory anti-TF antibody slightly prolonged clotting times, suggesting the presence of endogenous TF in RBC units. The concentration of TF, quantitated in an activity-based assay, did not change significantly over time for 3 of 4 donors and was within the range of 40-130 fM. For the fourth donor, TF concentration reached a maximum of 310 fM on day 10 and then decreased steadily to 60 fM on day 30.In an attempt to identify other components in RBC units responsible for the procoagulant activity, the effect of lactadherin, which binds to the phosphatidylserine exposed on cell membranes, was investigated. An addition of 100 nM lactadherin substantially prolonged the clotting time of the reconstituted RBC. Thus, in days 3-5 the clotting time in the presence of lactadherin was by 2.4-3.4-fold longer than in the absence of it. With increasing age of the RBC units, the effect of lactadherin diminished and at day 30, a prolongation of the clotting time did not exceed 1.3-1.8-fold. The addition of anti-TF monoclonal antibody in the presence of lactadherin further enhanced the clotting time of the reconstituted RBC.In conclusion, our data indicate that in stored units of RBC, the procoagulant activity is dependent upon the presence of active monocyte TF and phosphatidylserine exposed on blood cells and platelets. However, the failure of lactadherin in combination with the anti-TF antibody to completely inhibit the procoagulant activity in RBC units suggests that other components of blood (most likely platelets) support this activity as well. Disclosures:No relevant conflicts of interest to declare.

Stimulation of Plasminogen Activator Inhibitor Activity in Human Monocytes Infected with Dengue Virus

Human monocytes, in an essentially serum-free culture medium, were infected with dengue 2 virus in the presence of sub-neutralizing concentrations of antibody. Changes in procoagulant activity (PCA), in the plasminogen activator urokinase (UK), and the plasminogen activator inhibitor-2 (PAI-2) were quantitated. One day after exposure to dengue virus, the cell-associated PAI-2 activity in the infected monocytes was 562 +/- 9 mU/10(6) cells (mean +/- SE) compared to 206 +/- 56 mU/10(6) cells for uninfected monocytes. Supernatants of the infected cells also showed greater than 2-fold increase in PAI-2 activity. This increase in cell-associated and supernatant PAI-2 activity was maintained during 4 days of culture. UK activity was not detected in control and infected cells nor in their supernatants. PCA activity was the same in control and dengue virus infected monocytes when measured during 4 days of culture. These data suggest that dengue infected monocytes may affect fibrinolysis at a localized level through increased production of PAI-2.