Hemostatic Potential Research Articles

Системные гемостатические и гемостазиологические эффекты фибрин-мономера при прямом ингибировании тромбина в эксперименте

The systemic hemostatic and hemostasiological effects of intravenous injection of fibrin monomer (FM; 0.25 mg/kg) together with dabigatran etexilate (15-20 mg/kg) administration were compared to placebo (0.5 ml), prothrombin complex concentrate (d = 40 U/kg) and Eptacog alfa (activated) (d = 270 μg/kg) in a model of a controlled liver injury in 62 rabbits of the Chinchilla breed. It was found that FM, in comparison to placebo, reduced the volume of blood loss by 2.9 times and the rate of blood loss by 1.7 times, despite the dabigatran-induced hypocoagulation. Comparators did not show hemostatic efficacy. FM did not affect the parameters of the coagulogram (no visible hemostasiological effect), while the compared drugs showed some signs of increased hemostatic potential. It is assumed that the hemostatic effects of low, physiological doses of FM can be realized bypassing thrombin (factor IIa), which determines the need for further studies.

Reaction of hemostasis system in hypercapnic hypoxia after the course of mexidol assessed by the method of thromboelastography

Aim. To study the reaction of hemostasis system to a single effect of hypercapnic hypoxia of maximum intensity in rats and possibility of correcting hemostasis disorders by means of a preliminary course of an antihypoxant - mexidol. Methods. The study involved sexually mature male rats (48 specimens) of the Wistar line with an average mass of 274.0 ± 32.0 g. The rats were kept on a standard diet, food and water were fed once a day between 10 and 11 hours. In the evening, animals underwent a single hypercapnic hypoxia in a special flow chamber. The state of hypercapnic hypoxia of maximum intensity was modeled at O2 content of 5.0 %, CO2 - 5.0 % during a single 20-minute exposure. As a training regimen, a 30-fold course of mexidol was used, the drug was administered intraperitoneally to rats at a dose of 50 mg/kg for 1.5 hours prior to exposure to hypercapnic hypoxia. Results. After a single exposure to hypercapnic hypoxia of maximum intensity, shortening of the onset of clot formation, an increase of alpha angle, and maximum clot density were recorded. Also, the clot formation time shortened and the maximum clot lysis index increased. With a single exposure to hypercapnic hypoxia of maximum intensity after the course of mexidol, a decrease in the maximum clot density was recorded. Conclusion. A single exposure to hypercapnic hypoxia of maximum intensity was characterized by a shift of hemostatic potential toward hypercoagulability along with fibrinolytic system activation. The course use of antihypoxant mexidol, preceding hypercapnic hypoxia of maximum intensity, significantly reduces the risk of clot formation.

PIK3CA hotspot mutations and cyclooxygenase-2 expression in ovarian clear cell carcinomas: a close association with stromal features

Ovarian clear cell carcinomas (CCCs) have 2 distinct stromas: a hyalinized/mucoid stroma and a plasma cell-rich inflammatory stroma. Clinically, CCC is the most common ovarian cancer associated with thromboembolism. Recent studies suggested a potential role of PIK3CA mutation in the cyclooxygenase (COX) pathway, which mediates inflammation or hemostasis. In the present study, 54 ovarian CCCs and 3 CCC cell lines were analyzed for PIK3CA hotspot mutation and COX-2 expression with special reference to stromal features. Among the 54 CCCs, 20 (37.0%) and 8 (14.8%) were classified as CCCs with a hyalinized/mucoid stroma and an inflammatory stroma, respectively. PIK3CA mutation was identified in 11 (55%) of the 20 CCCs with a hyalinized/mucoid stroma, but not in any of the 8 CCCs with an inflammatory stroma. In contrast, COX-2 expression was frequent in CCCs with an inflammatory stroma (1/20 [5%] versus 7/8 [87.5%], respectively). Such a relationship between the PIK3CA mutation, COX-2 expression, and stromal features was repeated in the 3 CCC cell lines. Thromboembolism was noted in 9 (16.7%) of the 54 CCC patients, and it was more frequent in CCCs with a hyalinized/mucoid stroma (7/20 [35%]) than in those with an inflammatory stroma (0/8 [0%]). In conclusion, there is a difference in PIK3CA mutation, COX-2 expression, and paraneoplastic thromboembolism between CCCs with a different stroma. It is suggested that a different stromal feature, either hyalinized/mucoid change or inflammation, represents a different molecular genetic background or hemostatic potential in ovarian CCCs.

Spray-dried plasma deficient in high-molecular-weight multimers of von Willebrand factor retains hemostatic properties.

Dried plasmas can overcome logistical barriers that prevent fresh frozen plasma (FFP) usage in acute resuscitation, but processing of these products can detrimentally alter the composition. Spray-dried plasma (SpDP) from single units is deficient in high-molecular-weight multimers of von Willebrand factor (vWF), a critical facilitator of platelet adhesion and thrombus formation. We hypothesized that converting high-molecular-weight multimers to smaller-molecular-weight multimers would retain vWF's capacity to mediate platelet adhesion. SpDP obtained from untreated FFP was reconstituted with glycine-hydrochloric acid (HCl) and glycine (20 mM:50 mM) or pretreated with glycine-HCl (20 mM) or glycine-glycine-HCl (20 mM:50 mM) and reconstituted with water. In vitro hemostatic potential of SpDPs versus FFP or FFP spiked with 70 mM of glycine was evaluated, leading to a more detailed in vitro study of glycine-HCl-glycine (20 mM:50 mM) pretreated SpDP. Plasmas were combined with RBCs and platelets to observe global coagulation response. While vWF-ristocetin cofactor activity is significantly decreased (-41.13%; p < .0001) in SpDP, a model of vWF-mediated platelet adhesion to collagen under flow showed enhanced function (+13%; p < .01). Fewer microparticles, particularly of platelet origin, were observed in SpDP versus FFP (p < .0001). Small but significant differences in thromboelastography results were observed, although SpDP and FFP were within normal ranges. Comparable coagulability was observed in FFP and SpDP. The apparent paradox between vWF-ristocetin cofactor assay and vWF-mediated platelet adhesion may be explained by the increase in smaller multimers of vWF in SpDP, producing different outcomes in these assays.

Hemostatic profile under fluid resuscitation during rivaroxaban anticoagulation: an in vitro survey.

Uncontrollable bleeding is the leading cause of death in traumatically injured patients. The extent to which direct factor Xa inhibitors interfere with the applied resuscitation measures is presently unknown. In this study, we investigated the effect of the resuscitation fluids saline, albumin, fresh frozen plasma (FFP) and solvent/detergent (S/D)-treated plasma, fibrinogen concentrate, prothrombin complex concentrate (PCC), and combinations thereof on the hemostatic profile of rivaroxaban-anticoagulated whole blood and plasma. We used rivaroxaban-spiked whole blood and plasma from healthy donors, as well as plasma from patients on rivaroxaban, and mimicked a resuscitation approach in a 50% plasma dilution setting. Thromboelastography, thrombin generation, and fibrin generation clot lysis test were assessed using tissue factor to initiate coagulation and tissue plasminogen activator to induce clot lysis. Rivaroxaban resulted in a hypocoagulant state that remained largely unaltered upon subsequent 50% dilution with S/D-treated plasma or FFP. Using S/D-treated plasma as a diluent, clot stability decreased due to its low α2 -antiplasmin. Dilution with saline and albumin induced a profibrinolytic state and further deteriorated the impaired hemostatic potential of rivaroxaban-anticoagulated blood, even after PCC and fibrinogen support. Combined use of plasma (either FFP or S/D treated) and PCC, however, considerably improved both coagulation and clot stability. In the setting of rivaroxaban anticoagulation and major blood loss, transfusing plasma together with PCC may provide the most effective resuscitation approach with the notion that additional antifibrinolytic drug support (e.g., tranexamic acid) is likely required.

Coagulation and fibrinolytic potential of blood plasma in patients with stage VD CKD, treated by program hemodialysis, as the markers of thrombotic risk

Thrombotic complications, associated with hemostatic system disturbances in patients with stage VD chronic kidney disease (CKD), occur rather frequently. Hence, the search of early available biological markers in diagnosis of this complication is of great significance. Objective – to study coagulation potential of blood plasma in patients with stage VD CKD, treated by program hemodialysis, and to determine the markers of thrombotic risk. 88 patients (aged 26–65) with stage VD CKD, treated by program hemodialysis, were studied. Hemostatic potential of blood was determined by spectrophotometry; soluble fibrin level — by two-site enzyme-linked immune-sorbent quantitative assay; D-dimer — by enzyme immunoassay using monoclonal antibodies to D-dimer epitopes; protein C activity — by spectrophotometry with wavelength 405 nm; fibrinogen contents — by spectrophotometry with wavelength 280 nm. Statistical processing was performed by methods of variation statistics and correlation analysis. All patients were found to have significant increase of soluble fibrin level (4.03±0.15÷4.62±0.31 mg/ml) (р &lt;0.001), but there was a group of patients (n=25), who demonstrated increased coagulation potential, (р &lt;0.001), significantly prolonged fibrinolysis (р &lt;0.001) and increased soluble fibrin concentration (5.36±0.61÷5.78±0.82 µg/ml) (р &lt;0.001) along with the tendency to decreased C protein level and no response of D-dimer to increased soluble fibrin level. Detected changes in coagulation properties of blood plasma can serve the markers of thrombotic risk. Thus, the patients with stage VD CKD, treated by program hemodialysis, have high risk of thrombosis, associated with high concentration of soluble fibrin and fibrinogen. But in this category of patients, rather low fibrinolytic potential, as well as the level of natural anticoagulant — C protein — is observed. The studied homeostatic parameters can be used as the markers of thrombotic risk.

Оценка протромботического фенотипа у асимптомных носителей мутации G1691A в гене фактора V и/или мутации G20210A в гене протромбина с помощью теста генерации тромбина

Введение. К числу безусловных наследственных детерминант тромбофилии относятся мутации в генах факторов II (G20210A) и V (G1691A). Однако их наличие, особенно в гетерозиготной форме, не всегда приводит к развитию тромботических осложнений, что свидетельствует о целесообразности поиска новых объективных методов выявления протромботического фенотипа у носителей рассматриваемых мутаций. Тест генерации тромбина (ТГТ) отражает состояние гемостаза индивидуума в совокупности взаимодействия прокоагулянтных и антикоагулянтных механизмов и позволяет эффективно выявлять гиперкоагуляцию. Цель исследования: установить целесообразность использования ТГТ для оценки гемостатического потенциала у асимптомных носителей мутаций в генах фактора V (G1691A) и/или протромбина (G20210A). Материалы и методы. Обследовано 42 асимптомных носителя мутации FV G1691A и/или FII G20210A (14 мужчин и 28 женщин, средний возраст — 37,0 ± 15,0 лет). Постановка ТГТ выполнялась в бедной тромбоцитами плазме. В тромбинограмме оценивали следующие показатели: PT (Peak thrombin — максимальное количество тромбина, образующегося в образце), ETP (endogenous thrombin potential — эндогенный тромбиновый потенциал), Lag-time — время инициации свёртывания и V (скорость образования тромбина). Результаты. Согласно полученным данным, гетерозиготное носительство мутаций FV G1691A и/или FII G20210A может ассоциироваться как с протромботическим, так и с нормальным фенотипом. У асимптомных носителей Лейденской мутации повышенные значения ЕТР и РТ обнаружены в 44% случаев, в то время как резистентность к активированному протеину С — в 67%. У большей части носителей мутации в гене протромбина отмечены превышающие норму значения ЕТР и РТ (71% и 57% случаев, соответственно). Скорость генерации тромбина превышала нормальные величины у 57% носителей мутации FV G1691A и у 64% носителей мутации FII G20210A. Значительную часть обследованных можно охарактеризовать как имеющих промежуточный протромботический фенотип, учитывая наличие у них одновременно как нормальных, так и патологических показателей ТГТ. Заключение. ТГТ является перспективным методом в плане создания индивидуального профиля риска для асимптомных носителей мутаций, ассоциированных с наследственной тромбофилией. Introduction. Mutations in genes of factors II (G20210A) and V (G1691A) are well known determinants of hereditary thrombophilia, but their presence, especially in the heterozygous form, does not always lead to the development of thrombotic complications.This indicates the importance of objective methods for the detection of prothrombotic phenotype in carriers of these mutations. Thrombin generation test (TGT) demonstrates the state of individual’s hemostasis in the interaction of procoagulant and anticoagulant mechanisms and allows to detect the hypercoagulability. Aim: to assess the hemostatic potential in asymptomatic carriers of FV G1691A or/and FII G20210A mutations by TGT. Materials and methods. We examined 42 asymptomatic carriers of FV G1691A mutation and/or G20210A prothrombin gene mutation (14 men and 28 women, average age — 37,0 ± 15,0 years). TGT was performed in platelet-poor plasma. In thrombinogram we assessed following parameters: PT (Peak thrombin is the maximum amount of thrombin formed in the sample), ETP (endogenous thrombin potential), Lag-time (coagulation initiation time) and V (thrombin generation rate). Results. According to data obtained, heterozygous carriage of FV G1691A and/or FII G20210A mutations can be associated with both prothrombotic and normal phenotypes. In asymptomatic carriers of Leiden mutation we revealed elevated values of ETP and RT in 44% of cases, while resistance to activated protein C — in 67%. The majority of FII G20210A mutation carriers demonstrated increased values of ETP and PT (71% and 57%, respectively). Thrombin generation rate exceeded normal values in 57% and 64% carriers of FV G1691A and FII G20210A mutations, respectively. The majority of examined patients can be characterized as having intermediate prothrombotic phenotype, taking into account that they had both normal and pathological values of TGT parameters. Conclusion. TGT is a perspective method for creating an individual risk profi le in asymptomatic carriers of mutations associatedwith hereditary thrombophilia.

Multiple electrode aggregometry as a method for platelet function assessment according to the European guidelines.

Platelets play an essential role in haemostasis. Assessment of their function is vital for anaesthesiologists evaluating haemostatic potential, especially during emergency operations. The monitoring of platelets function had been implemented into the European recommendations for management of perioperative and posttraumatic bleeding. One of the diagnostic methods described in the recommendations is multiple electrode aggregometry. As antiplatelet therapy becomes more widely used in modern medicine, this method, in contrast to standard laboratory tests, can significantly help to identify patients with drug-induced thrombocytopaty. The aggregometry enables prompt evaluation of the platelets aggregation which is very useful for everyday decision-making in goal-directed hemostatic therapy.

In-vitro and in-vivo evaluation of hemostatic potential of decellularized ECM hydrogels

Extracellular matrix (ECM) hydrogels with a porous microstructure and good swelling behavior were fabricated via lyophilization and cross-linked with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC). Platelet adhesion studies revealed that platelets easily adhered to hydrogels while coagulation studies showed rapid blood aggregate formation. In-vitro cytotoxicity studies showed ECM hydrogels are biocompatible. In-vivo studies using rat tail bleeding and rabbit arterial injury showed ECM hydrogels' ability in hemostasis. ECM hydrogels formed a physical barrier and activated platelets that resulted in rapid thrombin formation during in-vivo application. The present study revealed ECM hydrogels could be a potential biomaterial for hemostat application.

Haemostatic potential of human bone marrow-derived mesenchymal stromal cells in Wistar rats with carbon tetrachloride induced liver cirrhosis.

To evaluate the haemostatic potential of human bone marrow-derived mesenchymal stromal cells (BM-MSCs) in carbon tetrachloride (CCl4) induced liver cirrhosis in Wistar rats. This was an experimental study. Liver cirrhosis was induced in adult female Wistar rats using CCl4. Rats were randomly divided into 6 groups with ten rats in each group: group 1 (normal control group), group 2 (received only CCl4), group 3 (CCl4 + low dose BM-MSCs), group 4 (CCl4 + high dose BM-MSCs), group 5 (CCl4 + silymarin), group 6 (CCl4 + high dose BM-MSCs + silymarin). Thirty days after the treatment, blood samples were collected for liver enzyme level analysis, prothrombin time test and plasma fibrinogen estimations. The rats were then sacrificed, livers were excised and used for histopathological and scanning electron microscopy (SEM) study. BM-MSCs and the combination treatment of high dose BM-MSCs and silymarin effectively decreased the prothrombin time and increased plasma fibrinogen concentration in rats with CCl4 induced liver cirrhosis. BM-MSCs treatment produces significant anti-fibrotic effect which was supported by the liver enzyme level analysis, histopathology and SEM study. Results indicate that treatment of BM-MSCs in combination with silymarin had a better haemostatic effect when compared to the administration of BM-MSCs alone.

Porous electrospun starch rich polycaprolactone blend nanofibers for severe hemorrhage

Starch nanofiber based hemostat was prepared by electrospinning process for biomedical applications. Bead free uniform starch nanofiber along with polycaprolactone polymer was produced using new solvent combination. The swelling of the PCL/starch mat was 240% higher compared to pristine PCL mat. The blood clotting time of the developed PCL/starch mat was 156 s and the contact angle was 30.8°. The results suggest that the developed nanofibers exhibited good hemostatic potential with quick rate of clotting to control blood loss in traumatic injuries.

Impaired mitochondrial activity explains platelet dysfunction in thrombocytopenic cancer patients undergoing chemotherapy.

Severe thrombocytopenia (≤50×109 platelets/L) due to hematological malignancy and intensive chemotherapy is associated with an increased risk of clinically significant bleeding. Since the bleeding risk is not linked to the platelet count only, other hemostatic factors must be involved. We studied platelet function in 77 patients with acute leukemia, multiple myeloma or malignant lymphoma, who experienced chemotherapy-induced thrombocytopenia. Platelets from all patients - independent of disease or treatment type - were to a variable extent compromised in Ca2+ flux, integrin a β activation and P-selectin expression when stimulated with a panelIIbof3 agonists. The patients’ platelets were also impaired in spreading on fibrinogen. Whereas the Ca2+ store content was unaffected, the patients’ platelets showed ongoing phosphatidylserine exposure, which was not due to apoptotic caspase activity. Interestingly, mitochondrial function was markedly reduced in platelets from a representative subset of patients, as evidenced by a low mitochondrial membrane potential (P<0.001) and low oxygen consumption (P<0.05), while the mitochondrial content was normal. Moreover, the mitochondrial impairments coincided with elevated levels of reactive oxygen species (Spearman’s rho=−0.459, P=0.012). Markedly, the impairment of platelet function only appeared after two days of chemotherapy, suggesting origination in the megakaryocytes. In patients with bone marrow recovery, platelet function improved. In conclusion, our findings disclose defective receptor signaling related to impaired mitochondrial bioenergetics, independent of apoptosis, in platelets from cancer patients treated with chemotherapy, explaining the low hemostatic potential of these patients.

Chitin/silk fibroin/TiO2 bio-nanocomposite as a biocompatible wound dressing bandage with strong antimicrobial activity

Interconnected microporous biodegradable and biocompatible chitin/silk fibroin/TiO2 nanocomposite wound dressing with high antibacterial, blood clotting and mechanical strength properties were synthesized using freeze-drying method. The prepared nanocomposite dressings were characterized using SEM, FTIR, and XRD analysis. The prepared nanocomposite dressings showed high porosity above 90% with well-defined interconnected porous construction. Swelling and water uptake of the dressing were 93%, which is great for wound dressing applications. Haemostatic potential of the prepared dressings was studied and the results proved the higher blood clotting ability of the nanocomposites compared to pure components and commercially available products. Besides, cell viability, attachment and proliferation by MTT assay and DAPI staining on HFFF2 cell as a Human Caucasian Foetal Foreskin Fibroblast proved the cytocompatibility nature of the nanocomposite scaffolds with well improved proliferation and cell attachment. To determine the antimicrobial efficiencies, both disc diffusion method and colony counts were performed and results imply that nanocomposite scaffolds have high antimicrobial activity and could successfully inhibit the growth of E. coli, S. aureus, and C. albicans. Moreover, based on these results, the prepared chitin/silk fibroin/TiO2 nanocomposite dressing could serve as a kind of promising wound dressing with great antibacterial and antifungal properties.

Fibrinolytic abnormality associated with progression of pediatric solid tumor.

Thrombosis and hemorrhage are serious complications of pediatric solid tumor, and enhanced fibrinolysis associated with disseminated intravascular coagulation (DIC) is often observed. Fibrinolytic enzymes also play an important role in metastasis. Limited information is available, however, on the assessment of overall hemostatic function in children with malignant solid tumor. We have investigated the comprehensive hemostatic potential in these circumstances using simultaneous thrombin/plasmin generation assay (T/P-GA). Endogenous thrombin potential (T-EP) and plasmin peak height (P-Peak) were measured using T/P-GA in six children newly diagnosed with solid tumor at regular intervals during chemotherapy at the present hospital from 2013 to 2016. Four patients with metastasis were defined as the advanced group, and the other patients were defined as the non-advanced group. In the advanced group, the ratio of P-Peak to normal was higher than the slightly increased ratio of T-EP to normal (range, 1.2-2.1 vs 1.1-1.5, respectively). In the non-advanced group, however, the P-Peak ratio was relatively lower than the slightly increased T-EP ratio (range, 1.0-1.5 vs 1.1-1.5, respectively). Fibrin-fibrinogen degradation product was elevated in all patients except in one non-advanced brain tumor patient during this induction therapy (maximum, 11.6-161μg/mL). Uncontrolled fibrinolysis together with an imbalance between coagulation and fibrinolytic potential might lead to DIC. Further research is warranted to clarify comprehensive hemostatic function in pediatric patients with solid tumors to establish optimal supportive therapy, and possibly limit tumor progression in these critical disorders.

Effect of Sleeve Gastrectomy on Platelet Counts and Mean Platelet Volumes

Obesity is a chronic metabolic disorder associated with cardiovascular disease, characterized by a chronic proinflammatory and prothrombotic state. The size and hemostatic potential of circulating platelets (PLTs) differ, with larger PLTs containing more granules and producing greater amounts of vasoactive and prothrombotic factors. This study aimed to investigate the effect of laparoscopic sleeve gastrectomy (LSG) on PLT count and mean platelet volume (MPV) in morbidly obese patients. Two hundred five patients (females, n = 143; males, n = 62) who attended monitoring visits in the period prior to LSG and for 6months after surgery were included in this study. Routine physical examination findings and laboratory parameters recorded preoperatively were compared with the same parameters in the postoperative 6th month. The mean age of the patients was 37.36 ± 10.93years. The mean preoperative body mass index (BMI) of the patients was 47.65kg/m2, whereas the mean postoperative BMI at 6months was 31.49kg/m2. Prior to LSG, the mean PLT count was 314.16 ± 76.40 × 109/L. At the postoperative 6th month, the mean PLT count was significantly reduced (263.17 ± 65.67 × 109/L, p < 0.001). In the preoperative period, the MPV was 10.12 ± 0.88fL. In the postoperative period, it was significantly increased (10.41 ± 1.23fL, p > 0.001). Both preoperatively and postoperatively, PLT counts were significantly higher in females than in males. After LSG, the MPV increased in both females and males. The results demonstrated that PLT counts decreased and MPV levels increased significantly after LSG and that the decrease in PLT counts was independent of changes in BMI.

Procoagulant Effects of Low-Level Platelet Activation and Its Inhibition by Colchicine.

Platelets play an important role in diseases such as cardiovascular disease and cancer, especially through their release of extracellular vesicles (EVs) and role in thrombosis. The effects of the anti-inflammatory drug colchicine on platelets are not well understood. We investigated the effect of colchicine on the release of pro-coagulant EVs from platelets under low-level activation. Citrated platelet-rich plasma (PRP) from healthy donors was incubated with 2 mM colchicine or vehicle at 37°C for 30 minutes with gentle rotation. The incubation conditions caused mild platelet activation (expression of CD62P and increased surface lactadherin binding) and release of EVs expressing phosphatidylserine (PS, measured by binding of lactadherin), CD61 and CD62P, both of which were attenuated by colchicine. The incubation conditions shortened the delay to fibrin generation and this correlated with elevated levels of PS+/CD61+ EVs. Removal of EVs from plasma abrogated clot formation in the overall haemostatic potential (OHP) assay. Colchicine decreased levels of both PS+/CD61+ and CD62P+ EVs and abrogated the shortened delay to fibrin generation achieved by platelet activation. Similar results were observed after incubation of PRP with 200 µM vinblastine, suggesting a microtubular effect. An alternative method of platelet activation using platelet agonists 20 µM ADP or 10 µM epinephrine also increased CD62P+ EV levels, and this too was attenuated by prior incubation with colchicine. Our novel findings demonstrate procoagulant effects of low-level platelet activation and EV formation which are inhibited by colchicine.

Arsenic trioxide at conventional dosage does not aggravate hemorrhage in the first-line treatment of adult acute promyelocytic leukemia.

The arsenic trioxide (ATO) plus all-trans retinoic acid (ATRA) therapy has demonstrated a tremendous success in the first-line treatment of acute promyelocytic leukemia (APL). Actually, early death (ED) is currently thought as a major challenge in APL. ATO has been reported to inhibit platelet function in vitro, and whether it increases the ED rate by exacerbating the hemorrhagic symptoms remains to be investigated. Effects of ATO on platelet aggregation and adhesion were evaluated in vitro and in thirty-two complete remission (CR) and four newly diagnosed APL patients. Furthermore, concentrations of plasma total arsenic were monitored in APL patients via ICP-MS. The inhibition of platelet function, either aggregation or adhesion, did occur in vitro when the concentration of ATO reached 2μmol/L. However, in CR APL patients receiving ATO with normal platelet count, the platelets responded normally when being activated and so did those in the newly diagnosed patients with thrombocytopenia. Our data further showed that the conventional dosage of ATO reached a plasma concentration substantially below the required concentration to inhibit platelets. In the first-line treatment of APL, the use of ATO is safe and effective and does not compromise the hemostatic potential that may eventually increase ED rate.

Emicizumab, A Bispecific Antibody to Factors IX/IXa and X/Xa, Does Not Interfere with Antithrombin or TFPI Activity In Vitro.

Emicizumab is a humanized bispecific antibody that binds simultaneously to factor (F) IXa and FX replacing the cofactor function of FVIIIa. Because emicizumab recognizes FIX/FIXa and FX/FXa, a question may arise whether emicizumab competes with antithrombin (AT) and/or tissue factor pathway inhibitor (TFPI), thereby enhancing overall hemostatic potential by blocking their antihemostatic effects. To address this question, we performed enzymatic assays using purified coagulation factors to confirm whether emicizumab interferes with the action of AT on FIXa or FXa, or with the action of TFPI on FXa. In those assays, we found no interference of emicizumab on the actions of AT and TFPI. We next assessed emicizumab's influences on the anticoagulation actions of AT or TFPI in thrombin generation assays triggered with FXIa or tissue factor (TF) in AT-depleted or TFPI-depleted plasma supplemented with AT or TFPI in vitro. In those assays, we employed anti-FIXa and anti-FX monospecific one-armed antibodies derived from emicizumab instead of emicizumab itself so as to prevent emicizumab's FVIIIa cofactor activity from boosting thrombin generation. Consequently, we found that neither anti-FIXa, anti-FX monospecific antibody, nor the mixture of the two interfered with the anticoagulation actions of AT or TFPI in plasma. Although emicizumab can bind to FIXa and FXa, our results showed no interference of emicizumab with the action of AT or TFPI on FIXa or FXa. This indicates that the presence of emicizumab is irrelevant to the action of AT and TFPI, and thus should not alter the coagulant/anticoagulant balance related to AT and TFPI.

Comparative characteristics of the hemostatic potential in cord blood and in blood from premature and full-term newborns after birth according to the thromboelastography.

The comparative characteristic of indicators of thromboelastography of umbilical cord blood and venous blood for 1-3 days of life at full-term and premature newborns is carried out. The study included 40 full term and 68 preterm infants at 1-5 days of life. Body weight of children was 3413.8±54.6 g and 2039.4±75.9 g, gestational age - 40.0±0.3 and 33.5±0.33 weeks, respectively. Mixed umbilical cord blood and venous blood taken from the ulnar vein of a child for 1-3 days of life were studied. The obtained data indicate that the main focus in the performance of thromboelastograms in premature and full-term newborns in the umbilical and venous blood are preserved. In preterm infants in cord blood decreased activity of the plasma level and functional activity of platelets, as well as reduced coagulation potential in General. After birth, premature newborns in the venous blood showed a slowdown in blood clotting, a decrease in the rate of formation and strength of clots. There is also a decrease in the functional activity of platelets, coagulation index and a more pronounced change in hemostatic potential in the direction of hypocoagulation. In full-term children, changes in the functional state of platelets and clot lysis in the umbilical and venous blood after birth do not change significantly. Hypercoagulable orientation of hemostasis in these children at birth was established.

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.