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Journal of Biomechanical Engineering Apr 2022Shear-induced platelet activation is one of the critical outcomes when blood is exposed to elevated shear stress. Excessively activated platelets in the circulation can...
Shear-induced platelet activation is one of the critical outcomes when blood is exposed to elevated shear stress. Excessively activated platelets in the circulation can lead to thrombus formation and platelet consumption, resulting in serious adverse events such as thromboembolism and bleeding. While experimental observations reveal that it is related to the shear stress level and exposure time, the underlying mechanism of shear-induced platelet activation is not fully understood. Various models have been proposed to relate shear stress levels to platelet activation, yet most are modified from the empirically calibrated power-law model. Newly developed multiscale platelet models are tested as a promising approach to capture a single platelet's dynamic shape during activation, but it would be computationally expensive to employ it for a large-scale analysis. This paper summarizes the current numerical models used to study the shear-induced platelet activation and their computational applications in the risk assessment of a particular flow pattern and clot formation prediction.
Topics: Blood Platelets; Humans; Hydrodynamics; Platelet Activation; Stress, Mechanical; Thrombosis
PubMed: 34529037
DOI: 10.1115/1.4052460 -
Methods in Molecular Biology (Clifton,... 2021Hematogenous metastatic spread of cancer is strongly dependent on and triggered by an intensive interplay of tumor cells with platelets. Immediately after entering the...
Hematogenous metastatic spread of cancer is strongly dependent on and triggered by an intensive interplay of tumor cells with platelets. Immediately after entering the blood vascular system, tumor cells are surrounded by a platelet cloak, which protects them physically from shear stress and from attacks by the immune surveillance. Furthermore, tumor cell binding activates platelets, which in turn release growth factors and chemokines to recruit myeloid cells into the platelet/tumor cell microemboli, eventually create a permissive microenvironment in the early metastatic niche. Although the molecular mechanisms of tumor cells to activate platelets appear versatile being a matter of further research, interference with platelet activation turns out to be an attractive target to efficiently inhibit tumor metastasis. Some experimental assays are generally recognized to follow tumor cell-induced platelet activation (TCIPA), which provide an insight into the molecular mechanisms of TCIPA and allow searching for potential inhibitors. In this chapter, we describe the two most prominent experimental assays to follow TCIPA, namely platelet aggregation and platelet granule secretion, experimentally realized by dense granules´ ATP quantification. Although light transmission aggregometry and ATP detection from dense granule secretion are two age-old techniques, they are still highly relevant to provide reliable information concerning platelet activation status since all tumor cell-derived molecular triggers are covered and monitored in the experimental outcome.
Topics: Animals; Blood Platelets; Cell Degranulation; Flow Cytometry; Humans; Neoplastic Cells, Circulating; Platelet Aggregation; Platelet Function Tests
PubMed: 33742402
DOI: 10.1007/978-1-0716-1350-4_13 -
Methods in Molecular Biology (Clifton,... 2012Hemostasis is dependent upon the successful recruitment and activation of blood platelets to the site of a breach in the vasculature. Platelet activation stimulates the...
Hemostasis is dependent upon the successful recruitment and activation of blood platelets to the site of a breach in the vasculature. Platelet activation stimulates the rapid reorganization of the cortical actin cytoskeleton, resulting in the transformation of platelets from biconcave disks to fully spread cells. During this process, platelets extend filopodia and generate lamellipodia, resulting in a dramatic increase in the platelet surface area. Kohler-illuminated Nomarski Differential Interference Contrast microscopy has proved an effective tool to characterize platelet morphological changes in real time, and provides a useful tool to identify genetic and pharmacological regulators of platelet function.
Topics: Blood Platelets; Cell Adhesion; Cell Separation; Cell Shape; Humans
PubMed: 22130702
DOI: 10.1007/978-1-61779-307-3_7 -
British Journal of Haematology Jan 1966
Review
Topics: Animals; Blood Coagulation Disorders; Blood Platelets; Humans
PubMed: 5324586
DOI: 10.1111/j.1365-2141.1966.tb00121.x -
Journal of Comparative Pathology Oct 1992
Review
Topics: Animals; Blood Platelets; Hemostasis; Humans; Inflammation; Mammals; Microscopy, Electron; Wound Healing
PubMed: 1469123
DOI: 10.1016/0021-9975(92)90002-c -
Journal of Thrombosis and Haemostasis :... Jun 2011It has become clear that platelets are not simply cell fragments that plug the leak in a damaged blood vessel; they are, in fact, also key components in the innate... (Review)
Review
It has become clear that platelets are not simply cell fragments that plug the leak in a damaged blood vessel; they are, in fact, also key components in the innate immune system, which is supported by the presence of Toll-like receptors (TLRs) on platelets. As the cells that respond first to a site of injury, they are well placed to direct the immune response to deal with any resulting exposure to pathogens. The response is triggered by bacteria binding to platelets, which usually triggers platelet activation and the secretion of antimicrobial peptides. The main platelet receptors that mediate these interactions are glycoprotein (GP)IIb-IIIa, GPIbα, FcγRIIa, complement receptors, and TLRs. This process may involve direct interactions between bacterial proteins and the receptors, or can be mediated by plasma proteins such as fibrinogen, von Willebrand factor, complement, and IgG. Here, we review the variety of interactions between platelets and bacteria, and look at the potential for inhibiting these interactions in diseases such as infective endocarditis and sepsis.
Topics: Bacteria; Blood Platelets; Humans; Immunity, Innate; Platelet Activation
PubMed: 21435167
DOI: 10.1111/j.1538-7836.2011.04264.x -
Annales de Biologie Clinique 1986Platelets play a key role in hemostasis, thrombosis, atherosclerosis and their pathological consequences. It is possible to follow platelet activation in vivo by... (Review)
Review
Platelets play a key role in hemostasis, thrombosis, atherosclerosis and their pathological consequences. It is possible to follow platelet activation in vivo by measuring bleeding time, platelet count, existence of circulating platelet aggregates or platelet survival and sequestration. In vitro tests include measurement of platelet adhesion, aggregation alpha, and dense granule secretion. It is also possible to follow biochemical events linked to platelet activation such as prostaglandin metabolism, Ca2+ levels or platelet membrane modifications (receptors, glycoproteins, coagulant activities, antigens). Some of these markers of platelet activation are modified in diseases (thrombotic events, hyperlipoproteinemia) and the use of artificial surfaces. It is not always possible to know if the modifications are the cause or the consequence of the pathological event. Unfortunately, some results are questionable because of methodological procedures. Some of these tests have been used to follow the involvement of platelets in a pathological event or to evaluate a prethrombotic state in a patient. It is not yet possible to identify directly, or by the mean of a marker of platelet activation, a patient who is likely to experience a thrombotic episode.
Topics: Blood Platelets; Calcium; Humans; In Vitro Techniques; Platelet Activating Factor; Platelet Adhesiveness; Platelet Aggregation; Platelet Function Tests; Platelet Membrane Glycoproteins
PubMed: 3538949
DOI: No ID Found -
Current Pharmaceutical Design 2007Platelets are the principle effectors of cellular haemostasis and key mediators in the pathogenesis of thrombosis. A variety of membrane receptors determine platelet... (Review)
Review
Platelets are the principle effectors of cellular haemostasis and key mediators in the pathogenesis of thrombosis. A variety of membrane receptors determine platelet reactivity with numerous agonists and adhesive proteins, and therefore represent key targets for the development of antiplatelet drug therapy. Here, we summarise recent advances in the analysis of the complex platelet membrane system achieved through the integration of platelet biology and proteomics.
Topics: Animals; Blood Platelets; Cell Membrane; Humans; Platelet Membrane Glycoproteins; Proteomics
PubMed: 17897007
DOI: 10.2174/138161207781662911 -
Blood Reviews Nov 2014Since 1990, several techniques have been developed to photochemically inactivate pathogens in platelet concentrates, potentially leading to safer transfusion therapy.... (Review)
Review
Since 1990, several techniques have been developed to photochemically inactivate pathogens in platelet concentrates, potentially leading to safer transfusion therapy. The three most common methods are amotosalen/UVA (INTERCEPT Blood System), riboflavin/UVA-UVB (MIRASOL PRT), and UVC (Theraflex-UV). We review the biology of pathogen inactivation methods, present their efficacy in reducing pathogens, discuss their impact on the functional aspects of treated platelets, and review clinical studies showing the clinical efficiency of the pathogen inactivation methods and their possible toxicity.
Topics: Blood Platelets; Furocoumarins; Humans; Platelet Transfusion; Riboflavin; Ultraviolet Rays
PubMed: 25192602
DOI: 10.1016/j.blre.2014.07.005 -
Transfusion and Apheresis Science :... Feb 2010Platelet components are continuously agitated during storage to maintain platelet quality. During shipment, it is not practical to agitate platelets. Numerous studies... (Review)
Review
Platelet components are continuously agitated during storage to maintain platelet quality. During shipment, it is not practical to agitate platelets. Numerous studies have investigated the influence of various periods without agitation on the in vitro and in vivo properties of platelet products. This review will examine the outcomes of these studies and consider new developments in platelet storage which might improve platelet quality after interruptions of agitation which occur during platelet shipment.
Topics: Blood Platelets; Blood Preservation; Cell Survival; Humans; Membrane Potential, Mitochondrial; Motion; Organ Preservation Solutions; Oxygen Consumption; Plateletpheresis; Temperature; Time Factors; Transportation
PubMed: 19931491
DOI: 10.1016/j.transci.2009.10.006