Mechanisms Of Hemostasis Research Articles

External Bleeding and Advanced Biomacromolecules for Hemostasis.

Hemorrhage is a significant medical problem that has been an active area of research over the past few decades. The human body has a complex response to bleeding that leads to blood clot formation and hemostasis. Many biomaterials based on various biomacromolecules have been developed to either accelerate or improve the body's natural response to bleeding. This review examines the mechanisms of hemostasis, types of bleeding, and the in vitro or in vivo models and techniques used to study bleeding and hemostatic materials. It provides a detailed overview of the diverse hemostatic materials, including those that are highly absorbent, wet adhesives, and those that accelerate the biochemical cascade of blood clotting. These materials are currently marketed, under preclinical testing, or being researched. In exploring the latest advancements in hemostatic technologies, this paper highlights the potential of these materials to significantly improve bleeding control in clinical and emergency situations.

Hematological abnormalities in liver cirrhosis.

Hematological abnormalities are common in cirrhosis and are associated with various pathophysiological mechanisms. Studies have documented a prevalence of thrombocytopenia, leukopenia, and anemia in patients with compensated cirrhosis of 77.9%, 23.5%, and 21.1%, respectively. These abnormalities carry significant clinical implications, including considerations for invasive procedures, infection risk, bleeding risk, and prognosis. Previously, cirrhosis was believed to predispose patients to bleeding due to alterations observed in classical coagulation tests such as prothrombin time, partial thromboplastin time, international normalized ratio, and thrombocytopenia. However, this understanding has evolved, and cirrhosis patients are now also acknowledged as being at a high risk for thrombotic events. Hemostasis in cirrhosis patients presents a complex phenotype, with procoagulant and anticoagulant abnormalities offsetting each other. This multifactorial phenomenon is inadequately reflected by routine laboratory tests. Thrombotic complications are more prevalent in decompensated cirrhosis and may correlate with disease severity. Bleeding is primarily associated with portal hypertension, endothelial dysfunction, mechanical vessel injury, disseminated intravascular coagulation, endotoxemia, and renal injury. This review comprehensively outlines hematologic index abnormalities, mechanisms of hemostasis, coagulation, and fibrinolysis abnormalities, limitations of laboratory testing, and clinical manifestations of bleeding and thrombosis in patients with liver cirrhosis.

Engineering High-Performance Composite Cellulose Materials for Fast Hemostasis.

The development of an effective hemostatic agents is of vital importance for saving wounded individuals from uncontrolled hemorrhage, which is the main reason for preventable death after accidental injury. However, current high-performance hemostatic agents suffer from a cumbersome preparation procedures and poor biocompatibility. Here, we engineered a cellulosic-derived aerogel material by simply controlling the drying process of cellulose regeneration for fast hemostasis. Four different freeze-drying pretreatments were investigated. As compared with the other three, the cellulosic aerogel material prepared without freezing pretreatment exhibited the lowest crystallinity (21.3%) and the highest body fluid absorption capacity (20.3 times that of its own weight) due to its super hierarchical porous structure, which led to an excellent hemostatic performance in vitro blood coagulation (≈100 s). Moreover, the addition of gelatin and diatomite in the material could tune the functional groups and electrostatic properties of the aerogel and further enhance its hemostatic performance. Various characterizations, including X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), X-ray nanocomputed tomography (CT), scanning electron microscopy (SEM), and zeta potential analysis, were carried out to probe the structure-function relationship of the prepared material, and its mechanism of fast hemostasis was thereafter revealed. The results indicate that the developed aerogel is a cost-effective and feasibly scalable hemostatic material suitable for practical use in industry.

Whole Blood Aggregometry in Mice.

Aggregometry plays a crucial role in both clinical diagnostics and research within hematology, serving as a fundamental tool for understanding platelet function and its implications in physiological and pathological processes. In research, aggregometry provides insights into platelet aggregation dynamics and aids in understanding the underlying mechanisms of hemostasis, thrombosis, and related disorders. Light transmission aggregometry (LTA) and lumi-aggregometry, as well as whole blood aggregometry, are commonly employed methods. While LTA and lumi-aggregometry allow for specific platelet function assessment under controlled conditions, whole blood aggregometry provides a more physiologically relevant approach by evaluating platelet aggregation within the context of whole blood. Although both methodologies offer unique advantages, whole blood aggregometry allows for preservation of the native cellular environment, simplicity, and potential for better clinical correlation. In a clinical setting, with human blood samples, protocols are established for both LTA and whole blood aggregometry as they are frequently used diagnostic tools. A protocol for LTA and lumi-aggregometry in murine models has been described; however, to date, there is no standardized protocol for whole blood aggregometry in murine models accessible to hematology researchers. This article aims to outline a simple, basic protocol for murine whole blood aggregometry, offering an alternative method to the commonly used LTA aggregometry in research settings. Standardizing whole blood aggregometry protocols in murine models could enhance experimental reliability and facilitate translational research efforts in hematology. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Whole blood aggregometry in mice Support Protocol: Phenylhydrazine-induced anemia in wild-type mice Basic Protocol 2: Hematocrit percentage in mice.

Efficiency Analysis of Hemostatic Agents in Drainless Neck Surgery: Cellulose-Based Versus Liquid Fibrin Sealants.

Using liquid fibrin sealants has once again questioned the benefit of drain placement in head and neck operations. Cellulose-based hemostats offering different hemostasis mechanisms have scarcely been investigated in drainless neck surgeries.This study aimed to evaluate whether liquid fibrin sealant offers any advantage over cellulose-based hemostats in various head and neck surgeries. A prospective trial of patients who underwent various neck surgeries between 2020 and 2022. Baseline characteristics and postoperative outcomes were compared between the drain-placed and the drainless groups, with the latter sub-categorized into three groups: fibrin sealant, cellulose-based hemostats, and a combination of both. A total of 119 patients were included (63 thyroidectomies, 40 parathyroidectomies, and 16 sialoadenectomies). Fifty eight had a drain placed and 61 had no drain. In the drainless group, 23 patients received cellulose-based absorbable hemostats (SURGICEL®/ FIBRILLAR™); 18 patients had fibrin sealants (EVICEL®/TachoSil®/TISSEEL); in 16, a combination of both was used; and in four patients, no hemostatic agent was used. Three (5%) of the 61 drainless patients developed a seroma compared to one (2%) seroma in the drain-placed patients. No advantage was demonstrated using a combination of FIBRILLAR™ with a fibrin sealant nor for any used separately. Drain placement delayed patient discharge by at least one day compared to the group without a drain (p < 0.001). Drain placement offered a minor advantage in the postoperative course reducing rates of seroma formation, while delaying patient discharge by at least one day. There was no advantage in using a specific hemostatic agent over the other.

EFFECT OF VACCINATION OF PIGLETS AGAINST CIRCOVIRUS INFECTION ON MORPHOLOGICAL AND BIOCHEMICAL BLOOD INDICATORS

In immunized piglets, 6 and 13 days after application of the biological product, the hemomorphological status, compared with that of intact animals, was characterized by a reduced content of erythrocytes, hemoglobin and platelets, indicating a lower intensity of erythropoiesis and activity of the vascular-platelet mechanism of hemostasis, an increased number of eosinophils, monocytes, as well as lymphocytes (6 days after vaccination), indicating activation of cellular defense, an increase in ESR, probably due to an increase in the level of globulins. In their biochemical status, a reduced content of total protein was recorded, associated with its inclusion in the production of specific antibodies, an intensification of protein metabolism, as evidenced by an increased level of urea, increased values of ALT, AST and γGT, indicating a higher load on the liver, and the amount of bilirubin, characterizing an increase in its utilization function, a lower level of creatinine as a result of activation of the urinary system due to an increased antigenic load on the body, an excess of cholesterol, indicating a more pronounced lipid metabolism.

Biochemistry of the Thrombin-Like Enzyme and Its Purification from Iranian Echis Carinatus Snake Venom: Its Interaction with Platelet Receptors.

Snake venoms are rich in valuable substances that have medical potential in the diagnosis and treatment of hemostatic diseases. The present paper was aimed at the purification and functional characterization basis of a thrombin-like enzyme and its role in the functioning of the coagulation cascade and platelet aggregation pathway. A thrombin-like serine protease was purified from the Iranian Echis carinatus venom (TLIECV), employing a one-step chromatographic procedure. This peptide was collected in high yield and purity by a single chromatographic step using RP-HPLC equipped with a C18 column. This peptide showed a 3000 Da molecular weight in gel-electrophoresis. Evidence in the SDS-PAGE gel has confirmed high recovery of fraction in optimal terms. Subsequently, this peptide was identified via its intact molecular mass and peptide mass fingerprint (PMF) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS). Multiple sequence alignments were performed by ClustalW, the Bioedit software. Molegro Data Modeller (MDM) 3.0 software was used to predict the putative tertiary structure of the peptide. The enzyme possessed fibrinogenolytic, procoagulant, and aggregation inducer properties. Moreover, the SDS-PAGE (12%) was applied to examine fibrinogenolytic function. The purified enzyme degraded the Aα chain of fibrinogen while the Bβ and γ chains were not digested. According to that, the deficient human plasma in factor X and normal human plasma were also coagulated by TLIECV, it takes part in the common and intrinsic routes of the coagulation cascade. These findings proved that TLIECV is a serine protease identical to procoagulant thrombin-like snake venom proteases; however, it specifically releases the Aα chain of bovine fibrinogen. Because of its function to make up for the deficiency of factor X and its platelet aggregation inducer property, TLIECV could be considered a molecular impact to reveal the hemostasis mechanisms.

The Effect of New Water-soluble 2-aminoheteryl-3-ium 4-(het)aryl-2-hydroxy-4-oxobut-2-enoates on the Hemostasis System &lt;i&gt;In vitro&lt;/i&gt;

Introduction. The hemostasis system is a set of functional, morphological and biochemical mechanisms of a living organism that ensure the preservation of the liquid state of the blood, the prevention and stopping of bleeding, as well as the integrity of blood vessels. Anticoagulants and hemostatic agents can significantly change the mechanism of hemostasis. Interest in the synthesis and search for compounds that affect the blood coagulation system remains high. Substances exhibiting anticoagulant and hemostatic effects have been found. The search for compounds among the products of organic synthesis that affect the hemostasis system seems relevant.Aim. To study the effect of new water-soluble 2-amino heteryl-3-ium 4-(get)aryl-2-hydroxy-4-oxobut-2-enoates on the hemostasis system using an in vitro model.Materials and methods. Direct interaction 4-(het)aryl-2-hydroxy-4-oxobut-2-enoic acids with heterocyclic amines have been obtained new water soluble 2-aminoheteryl-3-ium 4-(het)aryl-2-hydroxy-4-oxobut-2-enoates. The study of the effect of substances on the hemostasis system was carried out using the coagulometer "APK 4-02-P". Ethamsylate and sodium heparin were used as comparison drugs for hemostatic and anticoagulant activity, respectively. Acute toxicity of the compounds was determined by intravenous administration of aqueous solutions of the compounds to non-linear white mice of both sexes with the definition of LD50.Results and discussion. 10 New 2-aminoheteryl-3-ium 4-(het)aryl-2-hydroxy-4-oxobut-2-enoates have been synthesized. In vitro screening of the effect of compounds on the hemostasis system found that 3 substances have a pronounced anticoagulant effect, and 4 compounds showed hemostatic activity. Some patterns of the "structure-pharmacological action" relationship have been found. The studied butenoates can be classified as moderately toxic compounds according to the classification of chemical toxicity.Conclusion. Pharmacological screening in vitro of the effect of compounds on the hemostasis system was carried out. It was found that all the studied compounds have an effect on the blood coagulation system of varying degrees of severity. The combination of a pronounced pharmacological effect, low acute toxicity and water solubility of butenoates may become a prerequisite for further search and possible development of new domestic medicines that have an effect on the hemostasis system.

Sohlh2 promotes pulmonary fibrosis via repression of p62/Keap1/Nrf2 mediated anti-oxidative signaling pathway

Disturbance in the redox balance of alveolar epithelial cells (AECs) was considered as a causal factor for pulmonary fibrosis. The regulatory mechanisms of redox hemostasis in the development of pulmonary fibrosis remain largely unknown. Using a type II AEC-specific Sohlh2 conditional knock-in (CKI) mouse model, we found that Sohlh2, a basic HLH transcription factor, accelerated age-related pulmonary fibrosis. High-fat diet (HFD) resulted in a tremendous increase in lung inflammation and fibrotic changes in the lung tissues of Sohlh2 CKI mice. Sohlh2 overexpression led to a significant rise of intracellular ROS and apoptosis in the lung, mouse primary AECIIs, and human A549 cells, which was attenuated by ROS inhibitor (NAC). Sohlh2 enhanced oxidative stress via repressing p62/Keap1/Nrf2 mediated anti-oxidative signaling pathway. p62, a direct target of Sohlh2, mediated Sohlh2 effects on ROS generation and apoptosis in A549 cells. Hence, our findings elucidate a pivotal mechanism underlying oxidative stress-induced pulmonary fibrosis, providing a framework for aging-related disorder interventions.

2-Carba cyclic phosphatidic acid regulates blood coagulation and fibrinolysis system for repair after brain injury

Effective blood coagulation prevents inflammation and neuronal loss after brain injury. 2-Carba-cyclic phosphatidic acid (2ccPA), a biotherapeutic for brain injury, inhibits blood extravasation resulting from blood-brain barrier breakdown. However, the hemostasis mechanism of 2ccPA remains unclear. We determined the effects of 2ccPA-injection on blood coagulation and fibrinolysis using a needle-induced brain injury model. 2ccPA suppressed the expression of platelet degranulation-related genes. Immediately after brain injury, 2ccPA increased CD41+ platelet aggregation around the lesions and promoted fibrin aggregation. Additionally, 2ccPA supported fibrinolysis by upregulating plasminogen activator expression. These results suggest the acute effects of 2ccPA on brain hemostasis.

Use of anticoagulants in patients with traumatic brain injury and intracranial hematomas with the novel coronavirus infection as a concomitant pathology

Anticoagulant therapy is an integral part in the treatment and prevention of diseases and symptoms associated with pathological thrombosis in the human body. Anticoagulant therapy is traditionally not used in traumatic brain injury and hemorrhagic strokes with the formation of intracranial hematomas, intracerebral hematomas, and contusion hemorrhagic foci. However, in such diseases as the novel coronavirus infection, anticoagulant therapy is life-saving, since there is a high risk of developing various thromboses. The article considers the indications for the prescription of anticoagulants in the combination of these pathologies. The article discusses the possibility of using anticoagulants in patients with the novel coronavirus infection and intracranial hematomas, when there are two life-threatening diseases, in which anticoagulants are vital in one case and contraindicated in the other one. It is necessary to understand the complex mechanisms of hemostasis and weigh the risks and benefits in each case.

Impact of enteral administration of sodium hypochlorite on the mechanisms of inflammation and hemostasis in cancer patients with enteral insufficiency syndrome after multi-organ surgeries

Background. Enteral insufficiency syndrome is a complicated and multifactorial symptom complex that is accompanied with impaired functions of the gastrointestinal tract and is also one of the main causes of the development of endotoxicosis, systemic inflammatory response syndrome, abdominal sepsis, septic shock, and multi-organ failure. Thrombosis, which is associated with oncological diseases, is another common cause of death among patients with cancer after the progression of the disease. Development and implementation of new methods of detoxification in cancer patients in clinical practice after multi-organ surgeries is a major problem in intensive care. Purpose – to study the effectiveness of the enteral administration of sodium hypochlorite in cancer patients after multi-organ surgeries with systemic inflammatory response syndrome and to monitor the dynamics of certain markers of inflammation. Materials and methods. 53 patients with cancer were observed after having undergone multi-organ surgeries on the abdominal organs. The patients were divided into two groups: the main group (n=27), in which indirect electrochemical detoxification with sodium hypochlorite at a concentration of 0,06% was carried out by the drip infusion method through a gastrointestinal tube, and the comparison group (n=26), in which the treatment was performed according to standard treatment regimens. The examination was carried out at 3 stages – before NaClO infusion, on the 1st and the 7th day after the indirect electrochemical detoxification. Groups were compared according to age and anatomical and functional zones of the surgery (the surgery was performed on the abdominal organs). Results. Patients with stage 2/3 enteral insufficiency syndrome were treated with the method of electrochemical detoxification with sodium hypochlorite, which led to the inflammation reduction and normalization of the hemostatic system parameters. In patients, who were receiving sodium hypochlorite (the main group), the reduction in inflammatory mediators was observed: C-reactive protein (CRP) – from 22.1 to 5.6 mg/l, interleukin-6 (IL-6) – from 14,36 to 1.55 pg/ml, and also hemostatic parameters were improved. A decrease in the international normalized ratio (INR), fibrin, activated partial thromboplastin time (APTT), D-dimer level, blood clotting time, and an increase in prothrombin index were observed. Analyzing the effectiveness, it should be noted that the correction of the hemostatic system and the development of inflammation are significantly faster (on the 1st day after the NaClO infusion) compared with standard treatment methods while also ensuring plasma preservation. Conclusions. The use of the method of electrochemical detoxification with 0,06% NaClO in postoperative intensive therapy in enteral insufficiency syndrome prevents the development of systemic inflammation and hypocoagulation. The inclusion of sodium hypochlorite in the complex postoperative therapy during the day allowed the development of inflammation (a decrease in the expression of IL-6 and CRP) to be halted and procoagulative changes (a decrease in INR, fibrin, APTT, D-dimer level, blood clotting time, and an increase in prothrombin index) to be achieved.

Rational Design of Bioactive Materials for Bone Hemostasis and Defect Repair.

Everyday unnatural events such as trauma, accidents, military conflict, disasters, and even medical malpractice create open wounds and massive blood loss, which can be life-threatening. Fractures and large bone defects are among the most common types of injuries. Traditional treatment methods usually involve rapid hemostasis and wound closure, which are convenient and fast but may result in various complications such as nerve injury, deep infection, vascular injury, and deep hematomas. To address these complications, various studies have been conducted on new materials that can be degraded in the body and reduce inflammation and abscesses in the surgical area. This review presents the latest research progress in biomaterials for bone hemostasis and repair. The mechanisms of bone hemostasis and bone healing are first introduced and then principles for rational design of biomaterials are summarized. After providing representative examples of hemostatic biomaterials for bone repair, future challenges and opportunities in the field are proposed.

Advances in Hemostatic Hydrogels That Can Adhere to Wet Surfaces.

Currently, uncontrolled bleeding remains a serious problem in emergency, surgical and battlefield environments. Despite the specific properties of available hemostatic agents, sealants, and adhesives, effective hemostasis under wet and dynamic conditions remains a challenge. In recent years, polymeric hydrogels with excellent hemostatic properties have received much attention because of their adjustable mechanical properties, high porosity, and biocompatibility. In this review, to investigate the role of hydrogels in hemostasis, the mechanisms of hydrogel hemostasis and adhesion are firstly elucidated, the adhesion design strategies of hemostatic hydrogels in wet environments are briefly introduced, and then, based on a comprehensive literature review, the studies and in vivo applications of wet-adhesive hemostatic hydrogels in different environments are summarized, and the improvement directions of such hydrogels in future studies are proposed.

Incorporation of tissue factor-integrated liposome and silica nanoparticle into collagen hydrogel as a promising hemostatic system

Bleeding complications are associated with substantial tissue morbidities and mortalities. Biomimetic composite materials that possess the ability to sufficiently stimulate and augment different physiological mechanisms of hemostasis are highly desirable to reduce bleeding-related casualties, which, however, are still largely under-explored. This study aims to develop a composite hemostatic system by combining collagen hydrogel with tissue factor (TF)-integrated liposome and silica nanoparticle, which could integrate the platelet plug-promoting capacity of collagen with the abilities of the latter two components to activate the extrinsic and intrinsic pathways of coagulation respectively. Several hydrogel compositions were synthesized and characterized. We show that lipidated TF and silica were evenly distributed in the collagen-based hydrogels, while exhibiting tunable release kinetics in simulated body fluid. Time-to-coagulation test revealed that each component in the TF-liposome/silica/collagen ternary hydrogels was hemostasis-active, and their combination showed enhanced and potent procoagulant performance, without detectable cytotoxicity against NIH/3T3 model cells. These results suggest that collagen hydrogels with embedded TF-liposome and silica nanoparticle may serve as a platform for an effective hemostatic composite that incorporates all the basic known pathways of coagulation.

In vivo assessment of pharmacological potentials of different fractions of Fagonia olivieri DC

Introduction: Hemostasis mechanism involves blood coagulation as one of the step which is responsible for blood clot formation that restricts blood flow at site of injury. By inhibiting coagulation cascade and reducing thrombus formation, several cardiovascular diseases (CVD) and atherosclerosis can be prevented. Traditionally, Fagonia olivieri (zygophyllaceae) is reported in the treatment of diabetes, coughs, blood purifier, cooling agent, blood vascular diseases, digestive system disorders and cancer in initial stages. Objectives: Different fractions of F. olivieri methanolic extract were evaluated in this study for their anticoagulatory, anti-inflammatory and antidepressant potentials. Methodology: Anticoagulatory, anti-inflammatory and antidepressant potentials of ethyl acetate, butanol and aqueous extracts of F. olivieri were assessed using capillary tube experiment, carrageenan induced paw edema test and forced swim test respectively. Results: The results of this investigation have revealed that ethyl acetate and butanol fractions possess significant anticoagulatory potentials as compared to control (P=0.0002). Butanol extract showed highest anti-inflammatory activity. Maximum anti-depressant activity was shown by ethyl acetate followed by n-butanol and aqueous extracts. Conclusion: Hence, it can be concluded that F. olivieri exhibits anticoagulatory, anti-inflammatory and antidepressant potentials which justifies its use for the treatment of various disorders particularly blood vascular diseases.

Extracellular Vesicles As Markers of Inflammation and Hypercoagulability during the First Month of Sars-COV-2 Infection in Outpatients and Hospitalized Patients

During SARS-CoV-2 infection, a severe hypercoagulability state is observed due to the stimulus of multiple mechanisms of hemostasis, such as intrinsic and extrinsic coagulation pathways, activation of platelets, endothelial cells, monocytes and neutrophils endothelial and impaired fibrinolysis. As a consequence, thrombotic complications are common in the course of COVID-19. Microvesicles (MVs) are intracellular transmitters that participate in pathological conditions, such as inflammatory and infectious processes, and are capable of triggering prothrombotic mechanisms. Since MVs release is potentially associated with COVID-19-induced coagulopathy, our aim was to identify the moment during the time course of the disease when the stimulus for MVs release occurs and whether this was associated with adverse outcomes. Therefore, we evaluate changes in MVs markers levels during the first month of SARS-CoV-2 infection in patients with severe disease (patients hospitalized in an intensive care unit - ICU) as compared to outpatients. We also evaluated the association between MVs markers and: acute phase inflammatory biomarkers (C-reactive protein, CRP), hypercoagulability (D-dimer) and death. Blood samples of patients were collected on three occasions: before the 10th day of symptoms (6th to 10th day), in the third week of symptoms (16th to 20th) and in the fourth week of symptoms (21st to 25th day) for the quantification of the following MVs markers by flow cytometry: CD41A (platelet activation), CD162 (PSGL-1; leukocyte-platelet interaction), CD31 (endothelium-platelet interaction) and CD142 (tissue factor). Statistical tests of ANOVA with repeated measures, Mann-Whitney and regression methods were used. The population studied was 85 patients, 65 outpatients and 20 ICU patients. Forty-three were men (51%), with a median age of 41 years old. The concentration of MVs expressing CD31+, CD41+, CD162+ and CD142+ were persistently elevated in patients who required ICU compared to outpatients at the 3 moments studied, except for the levels of MVs-CD31+ and MVs-CD142+ that were similar between ICU and outpatients in the fourth week of symptoms. However, despite the differences between the groups, there were no significant changes in the concentration of MVs during the course of the disease within the groups. In subgroup analysis, we observed that increases in the levels of MVs-CD162+ and MVs-CD142+ in the third week of symptoms were associated with the risk of death (P=0.02 and P=0.06, respectively). We also observed that before the 10th day of symptoms there was no correlation between MVs markers, CRP and D dimer levels. However, throughout the course of the disease the association between MVs, coagulability and inflammation was evident. In the third week of symptoms, D-dimer levels were correlated with MV-CD31+ (r=0.52; P<0.0001), MV-CD162+ (r=0.35, P=0.001), MV-CD41A+ (r=0.44, P<0.0001) and MV-CD142+ (r=0.47, P<0.0001). In the fourth week of symptoms, these correlations remained unchanged. CRP values from the third week of symptoms were correlated with MV-CD31+ (r=0.56, P=<0.0001), MV-CD162+ (r=0.48, P<0.0001), MV-CD41A+ (r= 0.41, P=0.0001), and MV-CD142+ (r=0.56, P<0.0001). In the fourth week of symptoms, these correlations remained unchanged. In conclusion, MVs that express antigens related to platelet activation, leukocyte-platelet interaction and endothelium-platelet interaction, as well as those related to tissue factor are released during the course of COVID-19 in patients with severe disease. After the 4th week of symptoms, the release of these MVs was associated with signs of inflammation and hypercoagulability. Additionally, MVs that express tissue factor and leukocyte-platelet interaction antigens were particularly high among non-survivors, suggesting that these MVs may serve as markers of the risk of death. Finally, these findings suggest the participation of innate immunity and tissue factor pathways in the prognosis of COVID-19, and point towards a possible role of MVs as biomarkers of disease prognosis. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

EXTRACELLULAR VESICLES AS MARKERS OF INFLAMMATION AND HYPERCOAGULABILITY DURING THE FIRST MONTH OF SARS-COV-2 INFECTION IN OUTPATIENTS AND HOSPITALIZED PATIENTS

IntroductionDuring SARS-CoV-2 infection, a severe hypercoagulability state is observed due to the stimulus of multiple mechanisms of hemostasis, such as coagulation, activation of platelets, endothelial cells, monocytes and neutrophils and impaired fibrinolysis. As a consequence, thrombotic complications are common in the course of COVID-19. Microvesicles (MVs) are intracellular transmitters that participate in pathological conditions, such as inflammatory and infectious processes, and are capable of triggering prothrombotic mechanisms. Since MVs release is potentially associated with COVID-19-induced coagulopathy, our aim was to identify during the course of the disease when the stimulus for MVs release occurs and whether this was associated with adverse outcomes.ObjectiveWe evaluated changes in the levels of MVs markers during the first month of SARS-CoV-2 infection in patients (pts) with severe disease (hospitalized in an Intensive Care Unit ‒ ICU) as compared to outpatients. We also evaluated the association between MVs markers with: inflammatory biomarkers (C-reactive protein, CRP), hypercoagulability (D-dimer) and death.MethodsBlood samples were collected on three occasions: before the 10th day of symptoms, in the 3rd week of symptoms and in the 4th week of symptoms for the quantification of the following MVs markers by flow cytometry: CD41A (platelet activation), CD162 (PSGL-1; leukocyte-platelet interaction), CD31 (endothelium-platelet interaction) and CD142 (tissue factor). Statistical tests of ANOVA with repeated measures, Mann-Whitney and regression methods were used.ResultsThe population studied was 85 pts, being 25 from ICU. Mostly were men (51%), with a median age of 41 years. The concentration of MVs expressing CD31+, CD41+, CD162+ and CD142+ were persistently elevated in pts who required ICU compared to outpatients at the 3 moments studied, except for the levels of MVs-CD31+ and MVs-CD142+ that were similar between ICU and outpatients in the 4th week of symptoms. However, despite the differences between the groups, there were no significant changes in the levels of MVs during the course of the disease within the groups. In subgroup analysis, we observed that increases in the levels of MVs-CD162+ and MVs-CD142+ in the 3rd week of symptoms were associated with the risk of death (p=0.02 and p=0.06, respectively). We also observed that during the course of the disease an association between MVs, coagulability and inflammation was evident. In the 3rd week of symptoms, D-dimer levels were correlated with MV-CD31+ (r=0.52, p<0.0001), MV-CD162+ (r=0.35, p=0.001), MV-CD41A+ (r=0.44, p<0.0001) and MV-CD142+ (r=0.47, p<0.0001) and CRP values were correlated with MV-CD31+ (r=0.56, p=<0.0001), MV-CD162+ (r=0.48, p<0.0001), MV-CD41A+ (r= 0.41, p=0.0001), and MV-CD142+ (r=0.56, p<0.0001). By the 4th week of symptoms, both D-dimers and CRP correlations with the above MVs remained unchanged.ConclusionTo conclude, MVs that express antigens related to platelet activation, leukocyte-platelet interaction and endothelium-platelet interaction, as well as those related to tissue factor are released during the course of COVID-19 in pts with severe disease. After the 4th week of symptoms, the release of these MVs was associated with signs of inflammation and hypercoagulability. Additionally, MVs that express tissue factor and leukocyte-platelet interaction antigens were particularly high among non-survivors, suggesting that these MVs may serve as markers of the risk of death. Finally, these findings suggest the participation of innate immunity and tissue factor pathways in the prognosis of COVID-19, and point towards a possible role of MVs as biomarkers of disease prognosis.

Generation of cost-effective MXene@polydopamine-decorated chitosan nanofibrous wound dressing for promoting wound healing.

Herein, we designed and fabricated a MXene@polydopamine (MXene@PDA)-decorated chitosan non-woven fabric (M-CNF) hemostatic dressing with super hydrophilic properties for wound repair and regeneration. The M-CNF exhibit excellently wettability characteristics which can rapidly absorb water from blood. Moreover, M-CNF with 15mg/mL MXene@PDA (M-CNF-15) show better antibacterial performance, excellent blood-clotting performance, better blood cell and platelet adhesion ability than CNF, displaying both active and passive hemostatic mechanisms to accelerate blood clotting in mouse-liver injury model. In addition, the M-CNF-15 also shows better wound healed performance than Tegaderm™ film in a full-thickness skin defect model, and further demonstrating that the MXene@PDA can promote fibrinogen reformation the at the initial phases of the wound healing process. Therefore, this strategy for designing and manufacturing of multi-functional M-CNF wound dressing will have great potential for active local hemostasis and wound repair and regeneration.

Hemostatic powders for gastrointestinal bleeding: a review of old, new, and emerging agents in a rapidly advancing field.

Background and study aims Hemostatic powders are increasingly used to address limitations in conventional endoscopic techniques for gastrointestinal bleeding. Various agents exist with different compositions, characteristics, efficacy, and adverse events (AEs). We sought to review existing hemostatic powders, from preclinical to established agents. Methods A literature review on hemostatic powders for gastrointestinal bleeding was undertaken through a MEDLINE search from 2000–2021 and hand searching of articles. Relevant literature was critically appraised and reviewed for mechanism of action, hemostasis and rebleeding rate, factors associated with hemostatic failure, and AEs. Results The most established agents are TC-325 (Hemospray), EndoClot, and Ankaferd Blood Stopper (ABS). These agents have been successfully applied to a variety of upper and lower gastrointestinal bleeding etiologies, in the form of primary, combination, salvage, and bridging therapy. Few AEs have been reported, including visceral perforation, venous embolism, and self-limited abdominal pain. Newer agents include CEGP-003 and UI-EWD, which have shown results similar to those for the older agents in initial clinical studies. All aforementioned powders have high immediate hemostasis rates, particularly in scenarios not amenable to conventional endoscopic methods, but are limited by significant rates of rebleeding. Other treatments include TDM-621 (PuraStat) consisting of a liquid hemostatic agent newly applied to endoscopy and self-propelling thrombin powder (CounterFlow Powder), a preclinical but promising agent. Conclusions Rapid development of hemostatic powders and growing clinical expertise has established these agents as a valuable strategy in gastrointestinal bleeding. Further research will continue to refine the efficacy and applicability of these agents.