Background:Myeloproliferative neoplasms (MPNs) are characterized by an increased frequency of thrombotic complications. Patients with MPNs show little or no abnormalities in traditional coagulation tests. Chronic inflammation associated with pathological secretion of several inflammatory cytokines leads to activation of endothelial cells and imbalance between coagulation and anticoagulation systems.Aims:To estimate the natural anticoagulants activity and activated protein C resistance in MPNs patients.Methods:The study included 99 MPNs patients (aged 25 – 86 years, median = 55) and 43 healthy controls (aged 30‐73 years, median = 46). There were 65 female and 34 male in the study group. 75 (76%) patients were JAK2V617F positive, 24 (24%) were JAK2V617F negative. Antithrombin (AT), protein C (PC) activities and free protein S level (PS) estimation was performed by standard techniques. Thrombin generation was assessed by calibrated automated thrombinography (CAT) according to Hemker et al. Measurement was conducted in platelet poor plasma with or without thrombomodulin (TM). Such parameters as endogenous thrombin potential (ETP, nM∗min) and peak thrombin (Peak, nM) were evaluated. ETP and Peak sensitivity for TM were calculated as percent of these parameters decrease after TM adding to assay (S ETP, % and S Peak, % respectively). STATISTICA 6.0 package was used for data analysis. Parameter results were presented as median (Me) with 95% confidence intervals (CI), p<0.05 was considered statistically significant.Results:Protein C and protein S activity, Peak and ETP decrease were lower in patients with MPN than controls. Patients with Jak2V617F‐ had a tendency to lower sensitivity for TM in comparison with Jak2V617F+ patients. This fact could have a significant role in thrombotic complication development.Summary/Conclusion: Our results showed presence of activated protein C resistance probably caused by anticoagulant protein C system dysfunction. Jak2V617F influence on hemostatic parameters demands further investigations.image

Введение. Пандемия COVID-19 стала глобальной проблемой мирового сообщества. Основным патогенетическим механизмом заболевания представляется развитие иммунного тромбоза, результатом которого являются нарушение микроциркуляции, артериальные и венозные тромбозы, респираторный дистресс-синдром, полиорганная недостаточность. Изучение механизмов развития гиперкоагуляционных изменений у пациентов с COVID-19 вызывает огромный интерес и позволит улучшить исходы заболевания. Цель исследования: оценка состояния плазменного звена гемостаза у пациентов с коронавирусной инфекцией в остром периоде заболевания. Материалы и методы. Обследованы 59 пациентов с тяжелым и среднетяжелым течением коронавирусной инфекции, получавшие антикоагулянтную профилактику. Определяли следующие параметры системы гемостаза: активированное парциальное тромбопластиновое время, протромбиновый тест, концентрацию фибриногена, активность фактора VIII, антитромбина, протеинов C и S, содержание D-димера, фактора Виллебранда и гомоцистеина, а также генерацию тромбина методом калиброванной автоматизированной тромбинографии. Результаты. У пациентов с COVID-19 по сравнению со здоровыми лицами было выявлено увеличение концентрации фибриногена, уровня фактора Виллебранда, гомоцистеина и D-димера, значительное снижение уровня свободного протеина S, усиление генерации тромбина, снижение чувствительности к тромбомодулину. Была выявлена прямая корреляция между тяжестью состояния пациентов и уровнями фактора Виллебранда и гомоцистеина. Заключение. Несмотря на проводимую антикоагулянтную терапию, у пациентов с коронавирусной инфекцией отмечены выраженные признаки активации системы гемостаза, которые характеризуются как повышением отдельных маркеров гиперкоагуляции, так и значимым усилением генерации тромбина на фоне угнетения работы системы протеина С. Повышенный уровень гомоцистеина плазмы крови является дополнительным фактором риска, ухудшающим течение заболевания. Значительное повышение уровня фактора Виллебранда может быть неблагоприятным прогностическим признаком течения заболевания. Background. The COVID-19 pandemic is a global health care challenge. The concept of immunothrombosis has established as a central pathogenic factor leading to thrombosis complications, respiratory insufficiency and multiple organ failure. The study of hypercoagulability mechanisms in patients with COVID-19 may be useful for improving disease’s outcomes. Objectives: to evaluate plasma hemostasis in patients with coronavirus infection at the acute period of the disease. Patients / Methods. We examined 59 patients with severe and moderate coronavirus infection who received anticoagulant treatment. The following hemostasis parameters were determined: activated partial thromboplastin time, prothrombin test, fibrinogen, factor VIII, von Willebrand factor, D-dimer, protein C and S, homocysteine, and thrombin generation. Results. Fibrinogen, von Willebrand factor, D-dimer, homocysteine, and thrombin generation were higher in patients with COVID-19 than in healthy people, protein S was reduced. The direct correlation between the severity of the patient’s condition and the levels of von Willebrand factor and homocysteine was found. Conclusions. Patients with COVID-19 had significant hypercoagulability despite of the anticoagulant treatment. Signs of hemostasis activation are characterized by both increasing of hypercoagulation individual markers and thrombin generation with inhibition of protein C system. High level of plasma homocysteine is an additional risk factor that worsens the disease course. High level of von Willebrand factor may be an unfavorable prognostic sign of the disease course.

Thrombotic complications contribute significantly in morbidity and mortality of patients with Ph-negative myeloproliferative neoplasms (MPN) including polycythemia vera, essential thrombocythemia, and primary myelofibrosis. Vascular endothelium is essential component of hemostatic system, and its functionality failure plays important role in prothrombotic states development. This review comprises analysis of available data on assessment of endothelium state characteristics in Ph-negative MPN and their detection with different methods. The search of literature sources was carried out using PubMed and eLibrary databases. The analysis of research results obtained with the use of different estimation techniques indicates that patients with Ph-negative MPN are characterized by endothelium activation, damage, and, consequently, dysfunction. Endothelium abnormalities associated with myeloproliferation have an effect on all endothelial functions fulfillment. Endothelial dysfunction represents important component of thrombosis pathogenesis in Ph-negative MPN.

Background: Most recently, we have provided evidence that the Philadelphia-chromosome negative myeloproliferative neoplasms (MPN) are much more common in the background population than previously recognized. Thus, among 20.000 citizens in the Naestved Cohort, we have found 645 who carry the MPN driver mutations, JAK2V617F (JAK2) and CALR, of which the JAK2 mutation is by the far the most prevalent (613). The kinetics of the JAK2 mutation over time and its association with development in cell counts has not previously been described. Herein, we for the first time report a steady increase in the JAK2V617F mutation load from normal cell counts to the emergence of thrombocytosis and elevated plasma lactic dehydrogenase (LDH). Aims: To study the kinetics of the JAK2V617F mutation in the pre-MPN-diagnosis phase -a case story. Methods: Routine blood test and the JAK2V617F were serially determined in a female enrolled in the Naestved cohort of 20.000 citizens. Results: In December 2017, a 59-year-old female was enrolled in a study on the frequencies of and the kinetics of the MPN-driver mutations in the Naestved cohort as alluded to above. When entering the Naestved cohort study in April 2011, routine blood cell counts were all normal. By droplet digital PCR, the JAK2V617F mutation was detected at a level of 0.5 %. When again being enrolled in December 2017 due to previous documentation of