The method of in vivo evaluation of hemostasis: Spatial thrombodynamics

Global coagulation assays detect an early prothrombotic state in children with acute lymphoblastic leukemia

BACKGROUND

Pediatric patients with acute lymphoblastic leukemia (ALL) are at highest risk of venous thromboembolism during the induction therapy (IT). These events are not predictable by conventional coagulation assays.

OBJECTIVES

To investigate the utility of global coagulation assays (GCAs) for assessing the hemostatic state in children with ALL during IT.

METHODS

We included children with ALL (n = 15) and healthy controls (n = 15). Analyses were performed at different time points during IT of the AIEOP-BFM protocols. In addition to prothrombotic biomarkers, natural anticoagulant proteins, and in vivo thrombin generation (TG) markers, ex vivo TG was measured using the gold standard calibrated automated thrombogram method, automated ST Genesia, and thrombodynamics analyzer (TD). The latter also provided measurement of fibrin clot formation.

RESULTS

Different from conventional coagulation assays and in vivo TG markers, ex vivo GCAs detected increasing prothrombotic changes during IT. Particularly, TG measured with TD as expressed by endogenous thrombin potential was already significantly elevated at days 8 to 12 (P < .01) and continued to increase during IT compared with prior to beginning treatment, indicating a very early shift toward a procoagulant state. A similar pattern was observed for the rate of fibrin clot formation (stationary rate of clot growth: P < .01 at days 8-12). Remarkably, in patients developing thrombotic complications (n = 5), both GCAs, ST Genesia and TD, showed a significantly higher endogenous thrombin potential very early (already at days 8-12, P < .05), well before clinical manifestation.

CONCLUSION

GCAs capture prothrombotic changes early during IT in ALL pediatric patients. If confirmed, this approach will allow tailoring thromboprophylaxis in children with ALL at highest risk for venous thromboembolism.

Advances in haemostatic sponges: Characteristics and the underlying mechanisms for rapid haemostasis

In traumatized patients, the primary cause of mortality is uncontrollable continuous bleeding and unexpected intraoperative bleeding which is likely to increase the risk of complications and surgical failure. High expansion sponges are effective clinical practice for the treatment of wound bleeding (irregular/deep/narrow) that are caused by capillaries, veins and even arterioles as they possess a high liquid absorption ratio so can absorb blood platelets easily in comparison with traditional haemostasis treatments, which involve compression, ligation, or electrical coagulation etc. When in contact with blood, haemostatic sponges can cause platelet adhesion, aggregation, and thrombosis, preventing blood from flowing out from wounds, triggering the release of coagulation factors, causing the blood to form a stable polymerized fibre protein, forming blood clots, and achieving the goal of wound bleeding control. Haemostatic sponges are found in a variety of shapes and sizes. The aim of this review is to facilitate an overview of recent research around haemostatic sponge materials, products, and technology. This paper reviews the synthesis, properties, and characteristics of haemostatic sponges, together with the haemostasis mechanisms of haemostatic sponges (composite materials), such as chitosan, cellulose, gelatin, starch, graphene oxide, hyaluronic acid, alginate, polyethylene glycol, silk fibroin, synthetic polymers silver nanoparticles, zinc oxide nanoparticles, mesoporous silica nanoparticles, and silica nanoparticles. Also, this paper reviews commercial sponges and their properties. In addition to this, we discuss various in-vitro/in-vivo approaches for the evaluation of the effect of sponges on haemostasis.

The Role of Platelets in the Pathogenesis and Pathophysiology of Adenomyosis

Widely viewed as an enigmatic disease, adenomyosis is a common gynecological disease with bewildering pathogenesis and pathophysiology. One defining hallmark of adenomyotic lesions is cyclic bleeding as in eutopic endometrium, yet bleeding is a quintessential trademark of tissue injury, which is invariably followed by tissue repair. Consequently, adenomyotic lesions resemble wounds. Following each bleeding episode, adenomyotic lesions undergo tissue repair, and, as such, platelets are the first responder that heralds the subsequent tissue repair. This repeated tissue injury and repair (ReTIAR) would elicit several key molecular events crucial for lesional progression, eventually leading to lesional fibrosis. Platelets interact with adenomyotic cells and actively participate in these events, promoting the lesional progression and fibrogenesis. Lesional fibrosis may also be propagated into their neighboring endometrial-myometrial interface and then to eutopic endometrium, impairing endometrial repair and causing heavy menstrual bleeding. Moreover, lesional progression may result in hyperinnervation and an enlarged uterus. In this review, the role of platelets in the pathogenesis, progression, and pathophysiology is reviewed, along with the therapeutic implication. In addition, I shall demonstrate how the notion of ReTIAR provides a much needed framework to tether to and piece together many seemingly unrelated findings and how it helps to make useful predictions.

Hypercoagulation detected by routine and global laboratory hemostasis assays in patients with infective endocarditis

Background

Coagulation system is heavily involved into the process of infective endocarditis (IE) vegetation formation and can facilitate further embolization. In this study we aimed to assess the coagulation and platelet state in IE implementing a wide range of standard and global laboratory assays. We also aim to determine whether prothrombotic genetic polymorphisms play any role in embolization and mortality in IE patients.

Methods

37 patients with IE were enrolled into the study. Coagulation was assessed using standard coagulation assays (activated partial thromboplastin time (APTT), prothrombin, fibrinogen, D-dimer concentrations) and integral assays (thromboelastography (TEG) and thrombodynamics (TD)). Platelet functional activity was estimated by flow cytometry. Single nuclear polymorphisms of coagulation system genes were studied.

Results

Fibrinogen concentration and fibrinogen-dependent parameters of TEG and TD were increased in patients indicating systemic inflammation. In majority of patients clot growth rate in thrombodynamics was significantly shifted towards hypercoagulation in consistency with D-dimers elevation. However, in some patients prothrombin, thromboelastography and thrombodynamics were shifted towards hypocoagulation. Resting platelets were characterized by glycoprotein IIb-IIIa activation and degranulation. In patients with fatal IE, we observed a significant decrease in fibrinogen and thrombodynamics. In patients with embolism, we observed a significant decrease in the TEG R parameter. No association of embolism or mortality with genetic polymorphisms was found in our cohort.

Conclusions

Our findings suggest that coagulation in patients with infective endocarditis is characterized by general hypercoagulability and platelet pre-activation. Some patients, however, have hypocoagulant coagulation profile, which presumably can indicate progressing of hypercoagulation into consumption coagulopathy.

Peculiarities of blood coagulation disorders in patients with COVID-19

Aim. To study the relationship of hemostatic disorders with inflammation and estimate their role in the course and outcomes of COVID-19. Materials and methods. We examined 215 consecutive patients with moderate and severe forms of acute COVID-19. The patients were on anticoagulants and immunosuppressive drugs. Hemostasis was assessed using the thrombodynamics assay, thromboelastography, fibrinogen and D-dimer levels, prothrombin time, and soluble fibrin-monomer complexes (ethanol gelation test). The hemostatic parameters were correlated with hematological and biochemical tests, including markers of inflammation (C-reactive protein, interleukins 6 and 8), as well as with the disease severity and outcomes. Results. Laboratory signs of coagulopathy were revealed in the vast majority of the cases. Despite the use of low-molecular-weight heparins in the prophylactic and therapeutic doses, coagulopathy in COVID-19 manifested predominantly as hypercoagulability that correlated directly with the systemic inflammation and metabolic changes due to liver and kidney dysfunction. A direct relationship was found between the grade of coagulopathy and the severity of COVID-19, including comorbidities and the mortality. The chronometric hypocoagulability observed in about 1/4 cases was associated with a high level of C-reactive protein, which may decelerate coagulation in vitro and thereby mask the true inflammatory thrombophilia. Persistent hyperfibrinogenemia and high D-dimer in the absence of consumption coagulopathy suggest the predominance of local and/or regional microthrombosis over disseminated intravascular coagulation. Conclusion. The results obtained substantiate the need for laboratory monitoring of hemostasis and active prophylaxis and treatment of thrombotic complications in COVID-19.

Altered platelet and coagulation function in moderate-to-severe COVID-19

To reveal if coagulopathies relate to the course of COVID-19, we examined 255 patients with moderate and severe COVID-19, receiving anticoagulants and immunosuppressive drugs. Coagulopathy manifested predominantly as hypercoagulability that correlated directly with systemic inflammation, disease severity, comorbidities, and mortality risk. The prolonged clotting tests in about ¼ of cases were associated with high levels of C-reactive protein and antiphospholipid antibodies, which impeded coagulation in vitro. Contraction of blood clots was hindered in about ½ of patients, especially in severe and fatal cases, and correlated directly with prothrombotic parameters. A decrease in platelet contractility was due to moderate thrombocytopenia in combination with platelet dysfunction. Clots with impaired contraction were porous, had a low content of compressed polyhedral erythrocytes (polyhedrocytes) and an even distribution of fibrin, suggesting that the uncompacted intravital clots are more obstructive but patients could also be prone to bleeding. The absence of consumption coagulopathy suggests the predominance of local and/or regional microthrombosis rather than disseminated intravascular coagulation. The results obtained (i) confirm the importance of hemostatic disorders in COVID-19 and their relation to systemic inflammation; (ii) justify monitoring of hemostasis, including the kinetics of blood clot contraction; (iii) substantiate the active prophylaxis of thrombotic complications in COVID-19.

Accelerated Spatial Fibrin Growth and Impaired Contraction of Blood Clots in Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease associated with thrombotic complications. To elucidate pathogenic mechanisms, hemostatic disorders in RA were correlated with other laboratory and clinical manifestations. Hemostasis was assessed using relatively new complementary tests, the spatial growth of a plasma clot (Thrombodynamics assay), and contraction of whole blood clots. Platelet functionality was assessed with flow cytometry that quantified the expression of P-selectin and the fibrinogen-binding capacity of platelets before and after activation with a thrombin receptor-activating peptide. Parameters of fibrin clot growth and the kinetics of contraction of blood clots were significantly altered in patients with RA compared to the control group. In Thrombodynamics measurements, an increase in the clot growth rate, size, and optical density of plasma clots altogether indicated chronic hypercoagulability. The rate and extent of blood clot contraction in patients with RA was significantly reduced and associated with platelet dysfunction revealed by an impaired response to activation. Changes in the parameters of clot growth and contraction correlated with the laboratory signs of systemic inflammation, including hyperfibrinogenemia. These results confirm the pathogenic role of hemostatic disorders in RA and support the validity of fibrin clot growth and the blood clot contraction assay as indicators of a (pro)thrombotic state.

Determination of fibrin clot growth and spatial thrombin propagation in the presence of different types of phospholipid surfaces

In this work, we present a new method-Thrombodynamics-4D-for the assessment of both plasma and platelet contributions to clotting. Thrombodynamics-4D potentially allows for the determination of plasma or platelet disorders and the effects of various drugs on plasma clotting or on platelet procoagulant function. In this assay, clot formation in platelet-rich plasma or platelet-free plasma supplemented with phospholipids is activated with tissue factor immobilized on a surface. Spatial fibrin clot growth and thrombin concentration dynamics are registered by measuring light scattering of the fibrin clot and fluorescence of the product formed by cleavage of the synthetic fluorogenic substrate by thrombin, respectively. Here, we describe the preanalytical requirements, measurement methodology and calculation principles of assay parameters. Preanalytical and analytical variability and reference ranges of the assay are given. Additionally, we show some clinical examples, which determine the effect of anticoagulants, measure clotting dysfunction in patients with platelet or coagulation disorders and evaluate the effect of surgery.

New insights into neonatal coagulation: normal clot formation despite lower intra-clot thrombin levels

BACKGROUND

Healthy neonates exhibit no bleeding tendencies, but exhibit longer partial thromboplastin times than adults. Lower clotting factor levels may be balanced by lower inhibitor levels, which is not reflected in routine coagulation assays, but could result in normal clot formation in vivo. The novel thrombodynamics assay simulates a damaged vessel with tissue factor immobilized to a surface. We hypothesized that intra-clot thrombin levels and spatial fibrin clot formation with this assay are comparable in neonates and adults.

METHODS

Coagulation was tested in plasma from venous neonatal blood (N = 12), cord blood (N = 30), and adult blood (N = 20) using thrombodynamics and calibrated automated thrombography.

RESULTS

Neonates exhibited a higher initial rate of clot formation than adults (adult: 60.7 ± 3.9 µm/min; neonatal: 66.8 ± 3.9 µm/min; cord: 68.1 ± 3.3 µm/min; P < 0.001) and a comparable stationary rate of clot formation (adult: 35.8 ± 8.5 µm/min; neonatal: 37.0 ± 4.6 µm/min; cord: 36.0 ± 5.2 µm/min; P = 0.834). Intra-clot thrombin levels were lower in neonates (adult: 41.9 ± 11.2 AU/l; neonatal: 22.6 ± 10.2 AU/l; cord: 23.6 ± 9.7 AU/l; P < 0.001), but the longitudinal rate of thrombin propagation was comparable (adult: 27.2 ± 4.2 µm/min neonatal; 27.9 ± 2.9 µm/min; cord: 27.6 ± 3.4 µm/min; P = 0.862).

CONCLUSIONS

Despite lower intra-clot thrombin levels, neonates exhibit normal spatial fibrin clot growth, which concurs with clinically well-functioning hemostasis in healthy neonates.

Relationship Between Haemostasis Parameters and Anxiety Under Examination Stress: A Pilot Study

This work aims to clarify how blood coagulation parameters reflect mild stress response in males and females. Healthy student volunteers of both sexes were used in this pilot study. A new global sensitive assay of haemostasis, spatial thrombodynamics, along with conventional coagulometry approach were used to evaluate of blood coagulation parameters. Psychodiagnostics scales (according to Spielberger and Taylor) are employed to evaluate anxiety as stress-induced response. We have selected exam stress, which despite being a mild stressor may nevertheless cause somatic disorders. We provide the first evidence of a statistically significant increase in initial clot growth velocity in women, but not men, in response to exam stress. The exam situation produces higher situational anxiety in female volunteers, and so they express remarkable stress-induced haemostatic responses, including plasma- and platelet-based changes. In contrast, male volunteers do not express pronounced stress-induced changes in haemostasis, and only display a decrease in plateletcrit value and an increase in prothrombin time. Mild form of stress (exam) induces changes in some blood coagulation parameters. A statistically significant remarkable increase in V_init value and some other plasma- and platelet-based parameters has been seen in female students (but not male ones) under exam stress.

Thrombin Alters Human Endometrial Stromal Cell Differentiation During Decidualization

Vaginal bleeding and subchorionic hematomas are associated with increased risk of both early and late pregnancy loss. Thrombin generation may play a pivotal role in the development of these complications. To determine the effects of thrombin on human endometrial stromal cells (hESCs), cells were treated with thrombin at baseline or during decidualization with cyclic adenosine monophosphate (cAMP)+medroxyprogesterone acetate (MPA). Next-generation RNA sequencing revealed that markers of decidualization (IGF-1, IGFBP-1, and prolactin [PRL]) were induced after the initiation of decidualization, whereas thrombin suppressed insulin-like growth factor ( IGF)-1, Insulin-like growth factor binding protein ( IGFBP)-1, and PRL gene expression at baseline and during decidualization. These effects were mediated through protease activated receptor (PAR)-1- and PAR-1-independent pathways. Thrombin decreased the secretion of a key marker of decidualization (PRL), altered the morphological transformation of decidualizing hESCs, and activated genes involved in matrix degradation and proinflammatory chemokines ( Interleukin-8 and Interleukin-6). Genes encoding factors important for matrix stability ( Col1α1, LOX) were suppressed. We suggest that intrauterine bleeding and generation of thrombin accentuates leukocyte extravasation and endometrial inflammation, impairs decidualization, and endometrial support of early pregnancy.