Measuring thrombus stability at high shear, together with thrombus formation and endogenous fibrinolysis: first experience using the Global Thrombosis Test 3 (GTT-3)

© The Author(s) 2023. This is an open access article distributed under the Creative Commons Attribution License, to view a copy of the license, see: https://creativecommons.org/licenses/by-nc/4.0/Thrombus formation in a severely stenosed artery is initiated by high shear activation of platelets, with soluble platelet agonists, such as ADP and thromboxane, playing only a secondary role in the growth and stability of the thrombus. Conventional platelet function tests, however, assess only the soluble agonist-dependent pathway of platelet aggregation. As the thrombus evolves, its stability and ability to withstand dislodgement by arterial flow, will determine whether complete and persistent vessel occlusion will occur. The Global Thrombosis Test (GTT), an automated point-of-care technique, simulates the formation of thrombus in whole blood under high shear flow (shear rate >12,000 s-1) and measures the time for occlusive thrombus formation and spontaneous, endogenous thrombolysis/fibrinolysis. The latest GTT-3 model subjects the growing thrombus to upstream pressure, resembling that in a medium-sized artery, and provides additional assessment of thrombus stability and fibrinolysis rate. It can be used in three programs, including a new “hypershear” mode, whereby repetitive cycles of pressure are applied to the growing thrombus, increasing shear rate to ~22,000 s-1, such as that in patients on mechanical circulatory support. In addition to assessing the risk of arterial thrombosis, the GTT-3 could be used to assess the impact of antithrombotic medications on thrombus stability at high shear. While current anti platelet medications target the biochemical axis of platelet aggregation (soluble agonists) and also increase bleeding risk, novel shear-selective anti-platelet therapies may prevent thrombosis whilst preserving hemostasis. Future studies are needed to assess the usefulness of assessing thrombus stability on cardiovascular and pharmacological evaluation.Peer reviewe

Fibrinolysis in Platelet Thrombi

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/)The extent and duration of occlusive thrombus formation following an arterial atherothrombotic plaque disruption may be determined by the effectiveness of endogenous fibrinolysis. The determinants of endogenous fibrinolysis are the source of much research, and it is now broadly accepted that clot composition, as well as the environment in which the thrombus was formed, play a significant role. Thrombi with a high platelet content demonstrate significant resistance to fibrinolysis, and this may be attributable to an augmented ability for thrombin generation and the release of fibrinolysis inhibitors, resulting in a fibrin-dense, stable thrombus. Additional platelet activators may augment thrombin generation further, and in the case of coronary stenosis, high shear has been shown to strengthen the attachment of the thrombus to the vessel wall. Neutrophil extra cellular traps contribute to the fibrinolysis resistance. Additionally, platelet-mediated clot retraction, release of Factor XIII and resultant crosslinking with fibrinolysis inhibitors imparts structural stability to the thrombus against dislodgment by flow. Further work is needed in this rapidly evolving field, and efforts to mimic the pathophysiological environment in vitro are essential to further elucidate the mechanism of fibrinolysis resistance and in providing models to assess the effects of pharmacotherapy.Peer reviewe

Role, Laboratory Assessment and Clinical Relevance of Fibrin, Factor XIII and Endogenous Fibrinolysis in Arterial and Venous Thrombosis

Diseases such as myocardial infarction, ischaemic stroke, peripheral vascular disease and venous thromboembolism are major contributors to morbidity and mortality. Procoagulant, anticoagulant and fibrinolytic pathways are finely regulated in healthy individuals and dysregulated procoagulant, anticoagulant and fibrinolytic pathways lead to arterial and venous thrombosis. In this review article, we discuss the (patho)physiological role and laboratory assessment of fibrin, factor XIII and endogenous fibrinolysis, which are key players in the terminal phase of the coagulation cascade and fibrinolysis. Finally, we present the most up-to-date evidence for their involvement in various disease states and assessment of cardiovascular risk

Matrix metalloproteinases in the pathophysiology and progression of gynecological malignancies: could their inhibition be an effective therapeutic approach?

BACKGROUND: MMPs are a group of zinc-dependent endopeptidases implicated in the degradation of extracellular matrix components. Angiogenesis, wound healing and tissue remodeling are the main processes in which MMPs have been implicated. MMPs also seem to play a role in the pathophysiological processes during tumorigenesis and are thought to have predictive value for clinical outcome. Alterations in the regulation of MMP expression are considered to be of significant importance in the development and progression of gynecological malignancies. OBJECTIVES/METHODS: This study provides a literature review on the involvement of MMPs in the development and progression of gynecological malignancies, their clinical significance and the potential use of natural and/or synthetic MMP Inhibitors (MMPIs) as a more targeted therapeutic approach to these neoplasms. RESULTS/CONCLUSIONS: There is mounting evidence that MMPs play an important role in development and progression of gynecological malignancies. Current results provide the basis for further investigation of their role in malignancies, the therapeutic potential of their inhibition and the side-effects that can be expected from the modulation of matrix remodeling during therapeutic intervention. Focused research on the combination of MMPIs with cytotoxic and/or antiangiogenic compounds might provide the key to more successful therapeutic approaches towards gynecological and other malignancies

Role, laboratory assessment and clinical relevance of fibrin, factor XIII and endogenous fibrinolysis in arterial and venous thrombosis

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).Diseases such as myocardial infarction, ischaemic stroke, peripheral vascular disease and venous thromboembolism are major contributors to morbidity and mortality. Procoagulant, anticoagu-lant and fibrinolytic pathways are finely regulated in healthy individuals and dysregulated procoagulant, anticoagulant and fibrinolytic pathways lead to arterial and venous thrombosis. In this review article, we discuss the (patho)physiological role and laboratory assessment of fibrin, factor XIII and endogenous fibrinolysis, which are key players in the terminal phase of the co-agulation cascade and fibrinolysis. Finally, we present the most up-to-date evidence for their involvement in various disease states and assessment of cardiovascular risk.Peer reviewe

Biomarkers of Thrombotic Status Predict Spontaneous Reperfusion in Patients With ST-Segment Elevation Myocardial Infarction

© 2023 by the American College of Cardiology Foundation. Published by Elsevier. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1016/j.jacc.2023.03.388Background Spontaneous reperfusion, seen in ∼20% of patients with ST-segment elevation myocardial infarction (STEMI), manifests as normal epicardial flow in the infarct-related artery, with or without ST-segment resolution, before percutaneous coronary intervention (PCI). The drivers mediating this are unknown. Objectives The authors sought to relate spontaneous reperfusion to the thrombotic profile. Methods In a prospective study, blood from STEMI patients (n = 801) was tested pre-PCI to assess in vitro, point-of-care, occlusion times (OT) and endogenous lysis times (LT). Spontaneous reperfusion was defined as infarct-related artery Thrombolysis In Myocardial Infarction flow grade 3 before PCI. Patients were followed for major cardiovascular events (death, myocardial infarction, or stroke). Results Spontaneous reperfusion was associated with a longer OT (435 seconds vs 366 seconds; P < 0.001) and a shorter LT (1,257 seconds vs 1,616 seconds; P < 0.001), lower troponin, and better left ventricular function. LT was superior to OT for predicting spontaneous reperfusion (area under the curve for LT: 0.707; 95% CI: 0.661-0.753; area under the curve for OT: 0.629; 95% CI: 0.581-0.677). Among patients with spontaneous reperfusion, those with complete, vs partial ST-segment resolution, had a longer OT (P = 0.002) and a shorter LT (P < 0.001). Spontaneous reperfusion was unrelated to clinical characteristics or pain-to-angiography times. Over 4 years, patients with spontaneous reperfusion experienced fewer major adverse cardiovascular events than those without (4.1% vs 10.6%; P = 0.013), especially in those with both spontaneous reperfusion and complete ST-segment resolution (1.5% vs 10.1%; P = 0.029). Conclusions We demonstrate a novel hematological signature in STEMI patients with spontaneous reperfusion, namely, decreased platelet reactivity and faster endogenous fibrinolysis, relating to smaller infarcts and improved survival. This finding indicates a role for modulating thrombotic status early after STEMI onset, to facilitate spontaneous reperfusion and improve outcomes.Peer reviewe

Exposure to ethanol during neurodevelopment modifies crucial offspring rat brain enzyme activities in a region-specific manner.

The experimental simulation of conditions falling within "the fetal alcohol spectrum disorder" (FASD) requires the maternal exposure to ethanol (EtOH) during crucial neurodevelopmental periods; EtOH has been linked to a number of neurotoxic effects on the fetus, which are dependent upon the extent and the magnitude of the maternal exposure to EtOH and for which very little is known with regard to the exact mechanism(s) involved. The current study has examined the effects of moderate maternal exposure to EtOH (10 % v/v in the drinking water) throughout gestation, or gestation and lactation, on crucial 21-day-old offspring Wistar rat brain parameters, such as the activities of acetylcholinesterase (AChE) and two adenosine triphosphatases (Na(+),K(+)-ATPase and Mg(2+)-ATPase), in major offspring CNS regions (frontal cortex, hippocampus, hypothalamus, cerebellum and pons). The implemented experimental setting has provided a comparative view of the neurotoxic effects of maternal exposure to EtOH between gestation alone and a wider exposure timeframe that better covers the human third trimester-matching CNS neurodevelopment period (gestation and lactation), and has revealed a CNS region-specific susceptibility of the examined crucial neurochemical parameters to the EtOH exposure schemes attempted. Amongst these parameters, of particular importance is the recorded extensive stimulation of Na(+),K(+)-ATPase in the frontal cortex of the EtOH-exposed offspring that seems to be a result of the deleterious effect of EtOH during gestation. Although this stimulation could be inversely related to the observed inhibition of AChE in the same CNS region, its dependency upon the EtOH-induced modulation of other systems of neurotransmission cannot be excluded and must be further clarified in future experimental attempts aiming to simulate and to shed more light on the milder forms of the FASD-related pathophysiology