Intravascular Blood Coagulation Research Articles

Procoagulant CaCO3-embedded embolic microspheres can potentiate transcatheter arterial embolization of hepatocellular carcinoma

Transcatheter arterial embolization (TAE) represents a preferred therapeutic modality with minimal invasiveness for unresectable intermediate and advanced hepatocellular carcinoma (HCC) patients. However, its therapeutic outcome is restricted by incomplete occlusion of the whole tumor vasculature and exacerbated tumor immunosuppression due to the lack of ideal embolic agents. Herein, procoagulant embolic microspheres with tunable sizes are prepared by loading thrombin into calcium carbonate (CaCO3) nanoparticle-embedded gelatin microspheres (Th-CaCO3@gelatin MSs) via a microfluidic process. In this system, the yielded Th-CaCO3@gelatin MSs are capable of occluding main tumor-feeding blood vessels, while the released thrombin and Ca2+ triggered by the acidic tumor microenvironment can synergistically promote the formation of intravascular blood clots to occlude tumor capillaries. Meanwhile, the embedded CaCO3 nanoparticles can work as proton sponges to neutralize tumor acidity and thus effectively reverse tumor immunosuppression. Resultantly, TAE treatment with Th-CaCO3@gelatin MSs exhibits the most effective tumor suppression efficacy on orthotopic N1S1 HCC rat xenografts without causing obvious toxic effects. Therefore, this study highlights that our biocompatible embolic microspheres are capable of potentiating conventional TAE treatment by promoting pH-responsive tumor vascular infarction and neutralizing the acidic tumor microenvironment, with great potential in clinical translation.

Mechanics and microstructure of blood plasma clots in shear driven rupture.

Intravascular blood clots are subject to hydrodynamic shear and other forces that cause clot deformation and rupture (embolization). A portion of the ruptured clot can block blood flow in downstream vessels. The mechanical stability of blood clots is determined primarily by the 3D polymeric fibrin network that forms a gel. Previous studies have primarily focused on the rupture of blood plasma clots under tensile loading (Mode I), our current study investigates the rupture of fibrin induced by shear loading (Mode II), dominating under physiological conditions induced by blood flow. Using experimental and theoretical approaches, we show that fracture toughness, i.e. the critical energy release rate, is relatively independent of the type of loading and is therefore a fundamental property of the gel. Ultrastructural studies and finite element simulations demonstrate that cracks propagate perpendicular to the direction of maximum stretch at the crack tip. These observations indicate that locally, the mechanism of rupture is predominantly tensile. Knowledge gained from this study will aid in the development of methods for prediction/prevention of thrombotic embolization.

Effect of neutrophil extracellular traps (NET) on thrombosis: A literature review

Neutrophils are used by the innate immune system to form thrombi during many types of thrombosis. The inactivation of endogenous anticoagulants results in increased intravascular coagulation by increasing factor XII activation, decreasing plasmin production, or boosting the tissue factor-dependent extrinsic pathway. The creation of neutrophil extracellular traps (NET) by the externalization of decondensed nucleosomes and granule proteins supports neutrophil-dependent prothrombotic processes. Experimental thrombosis has been demonstrated to be caused by these traps, whether intact or fragmented, since they provide the means to enhance microvascular thrombosis. The von Willebrand factor increases platelet adhesion when neutrophils and activated platelets combine to form NET. Thus, neutrophils and externalized nucleosomes promote intravascular blood coagulation and thrombosis during infections and during conditions resulting from blood vessel damage.

Megakaryocyte-induced contraction of plasma clots: cellular mechanisms and structural mechanobiology

AbstractNonmuscle cell contractility is an essential feature underlying diverse cellular processes such as motility, morphogenesis, division and genome replication, intracellular transport, and secretion. Blood clot contraction is a well-studied process driven by contracting platelets. Megakaryocytes (MKs), which are the precursors to platelets, can be found in bone marrow and lungs. Although they express many of the same proteins and structures found in platelets, little is known about their ability to engage with extracellular proteins such as fibrin and contract. Here, we have measured the ability of MKs to compress plasma clots. Megakaryocytes derived from human induced pluripotent stem cells (iPSCs) were suspended in human platelet-free blood plasma and stimulated with thrombin. Using real-time macroscale optical tracking, confocal microscopy, and biomechanical measurements, we found that activated iPSC-derived MKs (iMKs) caused macroscopic volumetric clot shrinkage, as well as densification and stiffening of the fibrin network via fibrin-attached plasma membrane protrusions undergoing extension-retraction cycles that cause shortening and bending of fibrin fibers. Contraction induced by iMKs involved 2 kinetic phases with distinct rates and durations. It was suppressed by inhibitors of nonmuscle myosin IIA, actin polymerization, and integrin αIIbβ3–fibrin interactions, indicating that the molecular mechanisms of iMK contractility were similar or identical to those in activated platelets. Our findings provide new insights into MK biomechanics and suggest that iMKs can be used as a model system to study platelet contractility. Physiologically, the ability of MKs to contract plasma clots may play a role in the mechanical remodeling of intravascular blood clots and thrombi.

Activation of intravascular blood coagulation in the early postoperative period in reconstructive abdominoplasty

Purpose of the study: to determine the activity of intravascular blood coagulation during the abdominoplasty and justify pharmacological thromboprophylaxis.Material and Methods. An open prospective study was conducted on a group of 100 patients undergoing abdominoplasty. The risk of venous thromboembolism (VTE) before the surgery was assessed using the Caprini risk assessment model in 2010. Prothrombin (PT) and fibrinogen (FG) levels, soluble fibrin-monomer complexes (SFMC), euglobulin clot lysis time (ECLT), antithrombin III (AT-III) level, and protein C (PC) level were determined before and after the surgery.Results. Using the Caprini risk assessment model, patients were categorized by VTE risk as follows: moderate risk – 64% and high risk – 36%. After the surgery, an increase in PT by 12.3% and 15.5% on days 3 and 5 was observed (p < 0.01); an increase in FG by 0.49; 2.34 and 2.04 g/L on days 1, 3, and 5 was observed (p < 0.01); an increase in SFMC at all postoperative stages by 4.7; 8.2; 10.8 and 10.0 times (p < 0.01); an increase in ECLT by 2.8; 9.7, and 6.3 minutes on days 1, 3, and 5 (p < 0.001); and a decrease in AT-III and PC levels immediately after the operation by 18.8% and 8.9%, on day 1 by 14.2% and 11.2%, and on day 3 by 8.8% and 6.3% (p < 0.01).Conclusion. All patients undergoing abdominoplasty require pharmacological thromboprophylaxis due to moderate and high risk of venous thromboembolic complications. Abdominoplasty in the early postoperative period is accompanied by activation of plasma coagulation, inhibition of fibrinolytic system activity, and reduced activity of natural anticoagulants, which justifies the need for pharmacological thromboprophylaxis for at least 5 days.

Review of Topical Sodium Heparin 1000 IU/g Gel in Symptomatic Uncomplicated Superficial Thrombophlebitis.

Heparin, a mixture of sulfated polymorphic polysaccharides (glycosaminoglycan) chains of variable lengths and weights and a natural anticoagulant, is widely used in medical practice to prevent intravascular blood coagulation. Heparin has demonstrated antithrombotic and anti-inflammatory activity, and it is mostly administered systemically (intravenously or subcutaneously) for primary or secondary prevention of venous thromboembolism after surgical interventions, or immobilized patients, or on short-term antithrombotic therapy of patients with atrial fibrillation who must undergo treatment. However, since systemic administration of heparin could be, in certain cases, linked to an increased risk of bleeding, topical heparin is widely used for the prevention and treatment of local symptoms of peripheral vascular disorders, such as venous insufficiency, varicose veins, or superficial thrombophlebitis. This review summarizes the main safety and efficacy characteristics of the topical formulation of Heparin in Gel form (1000 International Units of Heparin/g Gel) currently in use, which has demonstrated an excellent efficacy and tolerability profile in reducing signs and symptoms of peripheral vascular disease, e.g., varicose syndromes and their complications, phlebothrombosis, thrombophlebitis, superficial periphlebitis, varicose ulcers, for post-operative varicophlebitis, sequelae of saphenectomy, for traumas and contusions, local edemas and infiltrates, subcutaneous hematoma and for traumatic affections of musculotendinous and capsuloligamentous apparatuses.

Modern approach to transfusion therapy of massive hemorrhage due to abnormally invasive placenta

Abnormally invasive placenta (AIP), or according to modern terminology PAS (placenta accrete spectrum disorders), is one of the most dangerous obstetric pathologies of pregnancy. It is quite often accompanied by massive blood loss during childbirth. Indicators of placenta accretion are increasing sharply, taking into account the frequency of delivery by cesarean section (CS).The objective: to determine the effectiveness of the blood loss recovery program in the case of delivery of pregnant women with AIP according to modern principles of transfusion therapy of massive blood loss with the use of innovative methods of surgical hemostasis.Materials and methods. At the clinical bases of the Department of Obstetrics and Gynecology N 1 of the Shupyk National Healthcare University of Ukraine during 2018–2023, 49 pregnant women with Placenta рercreta 3a,b were operated by fundal SC.The main group included 19 pregnant women with antenatally diagnosed Placenta percreta, who were delivered by fundal SC followed by hysterectomy with fallopian tubes and restoration of blood loss according to the principles of Damage Control Resuscitation – DCR (during 2021–2023) with priority given to transfusion with blood products with minimization infusion therapy; the comparison group included 30 pregnant women with a similar diagnosis and surgical approach, who had the recovery of massive blood loss in accordance with order No. 205 of the Ministry of Health of Ukraine “Obstetric bleeding” with the priority of rapid infusion therapy with crystalloids (2018-2020).Results. All pregnant women from Pl. percreta were delivered by CS and had hysterectomy at 35–37 weeks of pregnancy with lower median laparotomy and endotracheal anesthesia. The study groups did not differ in terms of the volume of surgery, but differed in the program of transfusion therapy to restore blood loss.In the main group, in which the early start of transfusion therapy using single-group fresh-frozen plasma and erythrocyte mass was applied, a significantly lower frequency of the development of the syndrome of disseminated intravascular blood coagulation, relaparotomy, cases of severe postoperative anemia and a shorter length of stay in the obstetric hospital were determined (p<0.05).Conclusions. The use of innovative surgical technologies, tranexamic acid preparations and early initiation of transfusion therapy with blood preparations with minimization of crystalloid infusion, according to the Damage Control Resuscitation strategy, in the development of massive intraoperative bleeding in cases of Placenta percreta allows to reduce the volume of blood loss and to prevent severe intra- and postoperative complication.

Features of disorders and methods of correction of the hemostasis system in women with antenatal fetal death

The improvement of the providing medical services quality to pregnant women remains an urgent issue in modern obstetrics. Women with perinatal losses deserve special attention, especially in the second half of pregnancy. Changes in the hemostasis system are an integral part of the development of pregnancy. The tendency to hypercoagulation has significant pathogenetic significance and can be the cause of a number of complications – miscarriage in the I trimester of pregnancy and preeclampsia, premature birth, antenatal fetal death (AFD) – in the II and III trimesters of pregnancy. Also, pregnancy is a background process for the activation of a number of diseases, in particular hereditary thrombophilia.The objective: to evaluate the changes in the hemostasis system in women with antenatal fetal death and the effectiveness of the use of low molecular weight heparins for the correction of disorders in the hemostasis system in this category of patients during childbirth and in the postpartum period.Materials and methods. 72 women were examined, including 42 pregnant women with AFD (main group) and 30 pregnant women with a physiological course of pregnancy, childbirth and the postpartum period (control group). The state of the hemostasis system was studied using a standard coagulogram. D-dimer was determined by immunoturbometric analysis.To assess the state of the hemostasis system, the following biochemical tests were used: procoagulant link – fibrinogen content and indicators: prothrombin index, activated partial thrombin time (APTT), thrombin time (TP), ancistrone time (AT), soluble fibrinogen-monomer complex (SFMC), factor X (FX); to evaluate the antithrombin system, the content of antithrombin-III (AT-III), protein C were determined; to characterize the state of the fibrinolytic system – the amount of plasminogen, α2-antiplasmin, fibrinogen degradation products (FDC).Thrombophilia markers and antiphospholipid antibodies were also determined. The preference was given to vaginal childbirth. During childbirth, mechanical compression of the lower limbs was applied using special compression stockings (compression level 2). In 12 hours after delivery thromboprophylaxis with low molecular weight heparins was started, the drug of choice being enoxaparin sodium. After 48 hours of the postpartum period, a comparative analysis of coagulogram indicators was performed to further determine the timing of thromboprophylaxis.Results. Analysis of family thrombotic anamnesis revealed risk factors in 12 (28.6%) patients of the main group. In close relatives of the first line, the presence of peripheral vein thrombosis was found – 5 (41.7%) cases, myocardial infarction under the age of 45 – 3 (25.0%) cases, pulmonary embolism – 1 (8.3%) case, transient ischemic attack of the brain – 3 (25.0%).In the control group only 2 (6.6%) patients had a family history of venous thromboembolism in first-line relatives. The analysis of the coagulation system shows significantly higher fibrinogen values (the main group – 5.3±0.2 g/l, the control group – 4.3±0.1 g/l; p<0.05), functional FX activity (the main group – 149.3±3.1%, control group – 107.3±2.7%; p<0.05), SFMC (main group – 15.9±1.2 μg/ml, control group – 7.8±0.9 μg/ml; p<0.05) and D-dimer (main group – 4.4±0.25 μg/ml, control group – 0.7±0.2 μg/ml; p< 0.05) in pregnant women of the main group. An increase in these indicators is a predictor of thrombus formation, activation of blood coagulation by the internal pathway with a decrease in the antithrombin reserve due to FX.During the correlation analysis, a strong direct relationship (r=0.8633) was established between the indicators of SFMC and FX in the blood serum of pregnant women of the main group, the combination of which determines the tendency to clot formation. Determination of markers for the most common types of thrombophilia shows the dominance of hereditary forms (prothrombin, Leiden mutation, MTHFR) in 43% of pregnant women of the main group.The implementation of the proposed treatment approach contributed to a significant decrease in the average concentration of fibrinogen 48 hours after delivery in postpartum women of the main group (main group: before delivery – 5.3±0.2 g/l, after 48 hours after delivery – 3.9±0.3 g/l; control group: 48 hours after delivery – 3.2±0.2 g/l; p<0.05) in combination with a synergistic decrease in the average indicators of SFMC (main group: before delivery – 15.9±1.2 μg/ml, 48 hours after delivery – 6.2±0.2 μg/ml; control group: 48 hours after delivery – 5.4±0.3 μg/ml; p<0.05) and FX (main group: before delivery – 149.3±3.1%, after 48 hours after delivery – 103.1±3.6%; control group: after 48 hours after delivery – 117.1±4.1%; p<0.05).Conclusions. Increased coagulation function was confirmed in pregnant women with antenatal fetal death (AFD). Thanks to the proposed method of correcting disorders in the hemostasis system, a decrease in the frequency of postpartum thromboembolism in women with AFD is achieved, as well as an improvement in the main indicators of the hemostasis system. This prevents the emergence of a chronic form of the syndrome of disseminated intravascular blood coagulation which is developed in the cases of AFD.

LİMFOSTİMULƏEDİCİ KORREKSİYANIN ŞƏKƏRLİ DİABETİN AĞIRLAŞMALARININ MÜALİCƏSİNDƏ ƏHƏMİYYƏTİ

The purpose of investigation was studying of disturbances of lipid metabolism and intravascular coagulabil-ity of blood and lymph, the state of lymph circulation in the pathogenesis of diabetic nephropathy in experi-ment, as well as the lymph stimulating method of their correction. Diabetes mellitus was reproduced in rabbits by intravenous injection of 5% solution of alloxan and diabetic nephropathy was reproduced by unilateral ne-phrectomy. Atorvastatin and sulodexide were used as a method of correction of disturbances of lipid metabo-lism and changes in the parameters of coagulability. Modeling of unilateral nephroectomy in the laboratory animals with diabetes mellitus resulted in disturb-ances of lipid metabolism and intravascular coagulation of blood and lymph. The main changes were discov-ered in lymph circulation system. Usage of atorvastatin and sulodexide as a method of correction of these changes showed a positive dynamic. The study showed that complex use of these preparations has positive ef-fects not only in the correction of dislipoproteinemia and intravascular coagulation, but it also stimulates for-mation and transport of lymph. It was established that stimulation of lymph circulation is an important point in the prevention and treatment of diabetic complications.

The role of D-dimer in stroke risk stratification in patients with atrial fibrillation

Introduction. D-dimer is an important indicator, which reflects the activation of intravascular blood coagulation and fibrinolytic system. There are some data confirming that D-dimer is associated with stroke development in patients with atrial fibrillation. However, D-dimer is not included in modern stoke risk stratification scales in patients with atrial fibrillation.Aim — to analyze the data devoted to the role of D-dimer in stroke risk stratification in patients with atrial fibrillation.General findings. D-dimer, despite several limitations, could be used in clinical practice as an indicator that is associated with stroke development in patients with atrial fibrillation. D-dimer level estimation could help to decide whether to use anticoagulant treatment in patients with low risk of stroke development or in those patients with a single non-sex CHA2DS2-VASc score risk factor.

Cerebral Venous Sinus Thrombosis following COVID-19 Vaccination: Analysis of 552 Worldwide Cases.

To date, billions of vaccine doses have been administered to restrain the current COVID-19 pandemic worldwide. Rare side effects, including intravascular blood clots, were reported in the general population after vaccination. Among these, cerebral venous sinus thrombosis (CVST) has been considered the most serious one. To shed further light on such an event, we conducted a literature search for case descriptions of CVST in vaccinated people. Findings were analyzed with emphasis on demographic characteristics, type of vaccine, site of thrombosis, clinical and histopathological findings. From 258 potential articles published till September 2021, 41 studies were retrieved for a total of 552 patients. Of these, 492 patients (89.1%) had received AZD1222/Vaxzevria, 45 (8.2%) BNT162b2/CX-024414 Spikevax, 15 (2.7%) JNJ-78436735, and 2 (0.3%) Covishield vaccine. CVST occurred in 382 women and 170 men (mean aged 44 years), and the median timing from the shot was 9 days (range 2–45). Thrombi were predominantly seen in transverse (84%), sigmoid (66%), and/or superior sagittal (56%) sinuses. Brain injury (chiefly intracranial bleeding) occurred in 32% of cases. Of 426 patients with detailed clinical course, 63% were discharged in good clinical conditions, at times with variable neurological sequelae, whereas 37% deceased, largely due to brain injury. This narrative review confirmed CVST as a rare event after (adenoviral vector) COVID-19 vaccination, with a women/men rate ratio of 2.25. Though the pathogenesis of thrombosis is still under discussion, currently available histopathological findings likely indicate an underlying immune vasculitis.

Detection of hemocoagulative activity of leukemia cells in acute myeloid leukemia and chronic myeloid leukemia

Peripheral blood and punctates taken in 13 primary patients, 6 of which had acute myeloblastic leukemia and 7 chronic myeloleukemia are studied. The peripheric blood in 3 healthy volunteers is studied for control. The method of revealing the tissue factor activity in blood cells of patients with leukemia is suggested. Previously described expression of the tissue factor by myeloblasts of patients with acute myeloblastic leukemia in peripheral blood as well as in bone marrow punctates is confirmed. It is shown that in patients with chronic myeloleukemia expression of the tissue factor activity is carried out by myeloblasts in peripheral blood as well as in bone marrow punctates. The results contradict the conception maintaining the principal impossibility of forming principal the tissue factor by blood cells. The development of disseminated intravascular blood coagulation syndrome and hemophilia under the influence of the tissue factor in leukocytes is possible not only in acute myeloblastic leukemia but in chronic myeloleukemia.

Pathogenesis of Two Faces of DVT: New Identity of Venous Thromboembolism as Combined Micro-Macrothrombosis via Unifying Mechanism Based on "Two-Path Unifying Theory" of Hemostasis and "Two-Activation Theory of the Endothelium".

Simple SummaryDVT is an intravascular blood clotting disorder that can be a life-threatening disease, particularly if it occurs in critically ill patients. Typically, distal DVT develops following a vascular injury associated with incidental trauma commonly involving lower extremities, which is transient and benign condition localized in the lower legs as solitary lesion. However, proximal/central DVT (i.e., venous thromboembolism) typically occurs in association with critical illnesses such as sepsis, diabetes, hypertension, cancer, autoimmune disease and others in the hospitalized patient, especially in the ICU. Recognition of different pathogenesis between distal DVT and proximal/central DVT is critically important because the prognosis is poorer in VTE. Its therapeutic approach should be different from distal DVT. The aim of this review is to identify the pathogenesis of two different types of DVT based on in vivo hemostatic mechanisms, which can explain their distinct phenotypes by clinical characteristics, laboratory data and imaging findings. An appropriate preventive measure can be put into the practice to avoid the onset of VTE. Additionally, should VTE be developed, proper and rational therapeutic regimen based on its pathogenesis can be designed for clinical trials to improve the outcome.Venous thrombosis includes deep venous thrombosis (DVT), venous thromboembolism (VTE), venous microthrombosis and others. Still, the pathogenesis of each venous thrombosis is not clearly established. Currently, isolated distal DVT and multiple proximal/central DVT are considered to be the same macrothrombotic disease affecting the venous system but with varying degree of clinical expression related to its localization and severity. The genesis of two phenotypes of DVT differing in clinical features and prognostic outcome can be identified by their unique hemostatic mechanisms. Two recently proposed hemostatic theories in vivo have clearly defined the character between “microthrombi” and “macrothrombus” in the vascular system. Phenotypic expression of thrombosis depends upon two major variables: (1) depth of vascular wall damage and (2) extent of the injury affecting the vascular tree system. Vascular wall injury limited to endothelial cells (ECs) in sepsis produces “disseminated” microthrombi, but intravascular injury due to trauma extending from ECs to subendothelial tissue (SET) produces “local” macrothrombus. Pathogen-induced sepsis activates the complement system leading to generalized endotheliopathy, which releases ultra large von Willebrand factor (ULVWF) multimers from ECs and promotes ULVWF path of hemostasis. In the venous system, the activated ULVWF path initiates microthrombogenesis to form platelet-ULVWF complexes, which become “microthrombi strings” that produce venous endotheliopathy-associated vascular microthrombotic disease (vEA-VMTD) and immune thrombocytopenic purpura (ITP)-like syndrome. In the arterial system, endotheliopathy produces arterial EA-VMTD (aEA-VMTD) with “life-threatening” thrombotic thrombocytopenic purpura (TTP)-like syndrome. Typically, vEA-VMTD is “silent” unless complicated by additional local venous vascular injury. A local venous vessel trauma without sepsis produces localized macrothrombosis due to activated ULVWF and tissue factor (TF) paths from damaged ECs and SET, which causes distal DVT with good prognosis. However, if a septic patient with “silent” vEA-VMTD is complicated by additional vascular injury from in-hospital vascular accesses, “venous combined micro-macrothrombosis” may develop as VTE via the unifying mechanism of the “two-path unifying theory” of hemostasis. This paradigm shifting pathogenetic difference between distal DVT and proximal/central DVT calls for a reassessment of current therapeutic approaches.

Pathology of lung‐specific thrombosis and inflammation in COVID‐19

BackgroundInfection by SARS‐CoV‐2 produces significant pulmonary pathology including endothelial damage with resultant thrombotic events. While pathologic features were described, there are limited data on the relationship of these changes to the inflammatory response and the production of thromboses. ObjectiveTo investigate pathology of COVID‐19‐related immunothrombosis. Patients/MethodsTissue samples from lung, kidney, brain and heart that were collected from 45 patients who died of COVID‐19. Histopathological examination was performed after H&E and Picro‐Mallory staining in combination with (immuno)fluorescence to visualize neutrophil extracellular traps. Ultrastructural alterations in lungs were studied with scanning and transmission electron microscopy. ResultsInflammatory changes and thrombosis were substantially more pronounced in the lung than in the kidney, heart, and brain. The most common pathologic finding was diffuse alveolar damage. In addition, most lung samples showed thrombi in vessels. The cause of death in single cases was massive pulmonary embolism. Ultrastructural examination revealed neutrophils attached to endothelium, perhaps as a step towards transendothelial migration. In addition, platelets were identified in the midst of fibrin as individual procoagulant balloon‐like cells. Ultrastructural examination demonstrated numerous virion‐like particles. ConclusionsStudying (ultra)structural features of the autopsy lung samples from patients with COVID‐19 has provided evidence for a pathogenic link between inflammation and thrombosis. The major features in the lungs of COVID‐19 patients comprised primary inflammatory thrombosis associated with diffuse alveolar damage. The lungs had pronounced circulatory changes with inflammation‐dependent intravascular blood clotting, whereas heart, brain, and kidneys had predominantly degenerative changes that were distinct from the lung pathology.

Decellularized Whole-Organ Pre-vascularization: A Novel Approach for Organogenesis.

Introduction: Whole-organ decellularization is an attractive approach for three-dimensional (3D) organ engineering. However, progress with this approach is hindered by intra-vascular blood coagulation that occurs after in vivo implantation of the re-cellularized scaffold, resulting in a short-term graft survival. In this study, we explored an alternative approach for 3D organ engineering through an axial pre-vascularization approach and examined its suitability for pancreatic islet transplantation. Methods: Whole livers from male Lewis rats were decellularized through sequential arterial perfusion of detergents. The decellularized liver scaffold was implanted into Lewis rats, and an arteriovenous bundle was passed through the scaffold. At the time of implantation, fresh bone marrow preparation (BM; n = 3), adipose-derived stem cells (ADSCs; n = 4), or HBSS (n = 4) was injected into the scaffold through the portal vein. After 5 weeks, around 2,600 islet equivalents (IEQs) were injected through the portal vein of the scaffold. The recipient rats were rendered diabetic by the injection of 65 mg/kg STZ intravenously 1 week before islet transplantation and were followed up after transplantation by measuring the blood glucose and body weight for 30 days. Intravenous glucose tolerance test was performed in the cured animals, and samples were collected for immunohistochemical (IHC) analyses. Micro-computed tomography (CT) images were obtained from one rat in each group for representation. Results: Two rats in the BM group and one in the ADSC group showed normalization of blood glucose levels, while one rat from each group showed partial correction of blood glucose levels. In contrast, no rats were cured in the HBSS group. Micro-CT showed evidence of sprouting from the arteriovenous bundle inside the scaffold. IHC analyses showed insulin-positive cells in all three groups. The number of von-Willebrand factor-positive cells in the islet region was higher in the BM and ADSC groups than in the HBSS group. The number of 5-bromo-2′-deoxyuridine-positive cells was significantly lower in the BM group than in the other two groups. Conclusions: Despite the limited numbers, the study showed the promising potential of the pre-vascularized whole-organ scaffold as a novel approach for islet transplantation. Both BM- and ADSCs-seeded scaffolds were superior to the acellular scaffold.

Ретроспективний аналіз летальних випадків коронавірусної хвороби

There was performed a statistical analysis of 164 records of pathological examination of persons who died of coronavirus disease during April-November, 2020. It is determined that the share of males was 62.20%, and females – 37.80%; the average age of the deceased persons was 64.40 ± 13.79 years. The largest number of lethal cases (57.32%) falls on the age category of 60-79 years, and the smallest (6.71%) – on the age category of 20-39 years. It is important that men predominate in all age groups. The most common direct causes of death were: respiratory failure – 78.05%, multiorgan failure – 17.07%. At the same time, respiratory insufficiency was dominant in all age categories, while the share of multiorgan failure was the largest in the group of persons aged 20-39 years. As a result of the analysis of thromboembolic complications found in 10.37% of cases, there were 3.05% of cases of acute coronary syndrome and acute cerebrovascular disorder, 1.83% of cases – acute thrombosis of the arteries of the lower extremities, 1.22% of cases – acute thrombosis of the mesenteric vessels, and 0.61% – disseminated intravascular coagulation of blood and acute pulmonary thromboembolism. Morphological examination of the lung tissue of the deceased persons revealed signs of diffuse alveolar damage involving the microcirculatory bed vessels in the pathological process. According to the results of bacteriological examination of the lungs there were revealed some signs of bacterial infection in 51.83% of cases, and signs of fungal infection – in 15.85% of cases. The most common (23.78%) was the growth of Klebsiella pneumoniae. The most common comorbidities were: coronary heart disease – 62.20%, hypertension – 29.27%, non-insulin dependent diabetes mellitus – 11.59%, obesity – 10.37%, anemia – 6.71% and chronic obstructive pulmonary disease – 2.44%. In 10.98% of cases diabetes was the main underlying disease. The data obtained may indicate an adverse effect of these diseases on the course of coronavirus disease.

Coagulation changes in COVID-19 infection and its implication in management

COVID-19 infection causes substantial changes in blood coagulation. Understanding this process helps management of the patient with least injury through therapeutic misadventurism. At the heart of the disease process, there is widespread endothelial and pulmonary alveolar epithelial cell damage related to the entry and proliferation of the virus and subsequent cellular response to virus invasion. The virus directly triggers fibrinolytic system which positively increase cellular viral load, cytokine generation, exudation in the alveoli, and both intravascular and extravascular blood coagulation and fibrinolysis. The major coagulation catastrophe comes from immunocoagulation and contribution by specific and non-specific cells (lymphocytes, monocytes, and neutrophils) augmenting the process. Hypoxia also contributes and plays an independent role. Platelet activation, complement activation, and vasculitis or vasculitis-mimics take part in the process. Some of these mechanisms are well established and some are yet to be worked out. COVID-19 infection unequivocally points out the great role of cellular activation and cytokines play in coagulation process; indicates classical anticoagulants, antiplatelets, statins, complement inhibitors, and steroids in managing this infection. The author concentrates on the pathobiology of blood coagulation with perspectives on how to manage each of these steps.

THE ROLE AND SIGNIFICANCE OF MORPHOLOGICAL CHANGES IN INTRAORGAN VESSELS IN ANIMALS DURING PATHOGENESIS OF BABESIOSIS

The aim of this study is to investigate morphological changes in intraorgan vessels and their role in susceptible animals in the pathogenesis of babesiosis. The material of the study included the intraorgan vessels of domestic dogs with clinically and laboratory confirmed babesiosis and wild mouse-like rodents from latent foci of babesiosis in Volyn, Zhitomir, Kiev, Poltava, Sumy, Kharkov, Chernigov regions. For histological study, we used standard fixation in a 12% aqueous formalin solution in phosphate buffer (pH = 7.0-7.2). After the post-fixation and dehydration, the samples were placed into paraffin blocks; then a series of histological slices (5 μm) were prepared. The preparations were stained with hematoxylin and eosin, according to Van Gieson technique. All test animals, regardless of the species taxonomy, were divided into two groups. The control group included clinically healthy animals (∑ = 36). The group under clinical study consisted of animals with clinically and laboratory confirmed babesiosis (∑ = 91). Histological changes in intraorgan vessels in the control group corresponded to the anatomical and functional parameters in the health. The preparations taken from the group with basesiosis demonstrate that microvessels are branched, different in size, spasmodic; their walls have signs of delamination and through lesions. Delamination developed gradually, started with the detachment of a small horizontal fragment of the outer layer. Defects in the integrity of microvessels resulted in penetrations; there was an active diapedesis of erythrocytes into the periovascular space. The accumulation of erythrocytes directed to the areas of connective tissue, branching of blood vessels, and fatty fragments. Hemorrhages were local in nature, concentrated in the form of small blurred foci of irregular shape. In the pathogenesis of babesiosis, the defects in the walls of blood vessels with their further penetration and dissection, hemorrhages, microvesiculation of the endothelium, and its desquamation play a critical role. Other manifestations included the development of intravascular blood coagulation, thrombosis, stasis, microcirculation disorders followed by ischemia, destructive and degenerative changes in the walls of blood vessels.

Current approaches to the use of antiplatelet and anticoagulant drugs in pregnant women with thrombocytopenia caused by hemostasis activation

Introduction. At present, hemostasis disorders still hold one of the lead places in the pathogenesis of reproductive losses associated with high risk of miscarriage and remain one of the major causes for developing serious obstetric complications. Relevance, efficacy and safety of using drugs containing acetylsalicylic acid (ASA) and low molecular weight heparins (LMWH) in pregnant women with thrombocytopenia comorbid with intravascular coagulation activation remain pressing issues. The study of thrombocytopenia pathogenesis during pregnancy and search for new methods of hemostasis correction are accounted for by high risk of developing diverse perinatal complications and necessity to conduct prophylactic measures for their prevention.Aim: to study hemostasis changes and clinical outcomes in pregnant women with thrombocytopenia, to substantiate the use of antiplatelet agents and anticoagulants in pregnant women with activated intravascular blood coagulation for preventing development of thromboembolic and placenta-associated complications of pregnancy.Materials and Methods. A multicenter prospective study was conducted by enrolling 299 pregnant women at a gestational age of22.85 [22.00; 25.00] weeks, whose average age was 31.06 [27.75; 35.00] years. There were distinguished three groups: main group (n = 124) consisted of pregnant women with lowered platelet count and activated intravascular blood coagulation, who received ASA preparations and LMWH in prophylactic doses for 4 weeks; pregnant comparison groups (n = 125) received no such drugs; control group (n = 50) consisted of women with normal platelet counts during physiological pregnancy. All patients underwent clinical, anamnestic and laboratory examination, and the clinical outcomes of pregnancy were assessed.Results. It was found that use of ASA (a combined drug: ASA 75 mg + magnesium hydroxide 15.2 mg/day) and LMWH (enoxaparin sodium) in pregnant women from the main group were noted to improve hemostasis parameters: via markedly increased platelet count, decreased fibrinogen level, prothrombin index as well as normalized antithrombin III level (p < 0.01). It was also found during treatment that the D-dimer level and the rate (83.6 ± 2.3 % and 72.4 ± 2.7 %) and the degree (86.4 ± 2.7 % and 74.4 ±2.8 %) of platelet aggregation in the main group (in contrast with comparison group) were significantly decreased (p < 0.01). The frequency of detected chronic placental insufficiency was significantly higher (p < 0.01) in the comparison group (n = 50; 41.32 %) vs. the main group after receiving ASA and LMWH (n = 20; 16.52 %). The incidence of moderate (p = 0.016) and severe (p = 0.018) preeclampsia was significantly higher in the comparison group vs. the main group. While comparing the volume of blood loss during delivery, there were no differences between the main group and the comparison group (p = 0.46); it was noted only a statistically significant difference compared to the control group (p = 0.04), in which the lowest blood loss was found (337.9 [200.0; 600.0] ml) in comparison with the other two groups (p1,3 = 0.05; p2,3 = 0.04). It should be noted that the volume of blood loss in all groups remained within the physiological permissible range.Conclusion. Our clinical and laboratory study allowed to substantiate relevance of using ASA and LMWH drugs in pregnant women with thrombocytopenia comorbid with confirmed activation of intravascular blood coagulation, for prevention of thromboembolic and placenta-associated complications of pregnancy as well as proved safety of such drugs during pregnancy.

Review of the pathogenesis, clinical manifestations and peculiarities of neuropsychic disorders caused by COVID-19

The article presents literature data numerous studies of patients with COVID-19. The available information helps to explain the nature and structure of the virus, the ways of penetration and its distribution in the human body, its interaction with the immune, nervous, endocrine, vascular, muscular systems, as well as the pathogenesis, clinic, diagnosis and treatment of this contingent of patients. Due to tropisms SARS-CoV-2 to the human cells specifi c S glycoprotein this virus can bind receptor human angiotensin-converting enzyme 2 (ACE-2), fuse with host cells and disseminate in the organism. Renin-angiotensin-aldosteron system (RAAS) plays an important role in regulation of blood vessels, heart, kidneys functions. ACE-2 has an infl uence on the infl ammatory, fi brotic and immunomodulatory mechanisms. Inhibition of these protection functions due to spread SARS-CoV-2 in human body leads to the progression of cardiovascular, renal and pulmonary diseases. Some authors describe indirectly the viral entry into the brain parenchyma by infecting the T-lymphocytes, that usually is accompanied by infl ammatory reactions with an increase in the specifi c cytokines such as interleukins (IL) — 6, IL-8, tumor necrosis factor, monocyte chemoattractant protein-1 (MCP-1). The peculiarities of the binding of the virus to the human cells are the presence of neurotropic properties and the ability to change the permeability of blood brain barier (BBB). Other authors note that the virus crosses the BBB directly through the olfactory neurons and also the brain’s circumventricular organs structures, surrounding the third and fourth ventricles, and promote the infection of nervous system. It can also cause intravascular coagulation and blood clotting, which may lead to various diseases of the nervous system. In this regard, an important task for neurologists is to further study the eff ect of the COVID-19 virus on the nervous system and prevent the occurrence of its complications.