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Hamostaseologie 2015Platelets are well-known for their major role in primary hemostasis and thrombosis. Cancer patients frequently manifest thrombotic events and present abnormalities in... (Review)
Review
Platelets are well-known for their major role in primary hemostasis and thrombosis. Cancer patients frequently manifest thrombotic events and present abnormalities in blood coagulation which appear to be linked to altered platelet function and turnover. Moreover, numerous studies indicate an intimate cross-talk between platelets and tumor growth, angiogenesis and metastatic dissemination. Finally, several experimental data and clinical trials suggest possible benefits of anti-platelet drugs on some cancers. Here, we will review the current state of basic biological research regarding the role of platelets in cancer progression. We also critically review the possible clinical applicability of some anti-platelet therapies to limit tumor growth and prevent metastatic dissemination.
Topics: Animals; Blood Platelets; Evidence-Based Medicine; Homeostasis; Humans; Models, Cardiovascular; Models, Immunological; Neoplasms; Platelet Aggregation Inhibitors; Thrombosis; Translational Research, Biomedical
PubMed: 26289826
DOI: 10.5482/hamo-14-11-0065 -
Thrombosis and Haemostasis Aug 2015Platelet P2Y12 inhibitors form a major part of the treatment strategy for patients with acute coronary syndromes (ACS) due to the importance of the platelet P2Y12... (Review)
Review
Platelet P2Y12 inhibitors form a major part of the treatment strategy for patients with acute coronary syndromes (ACS) due to the importance of the platelet P2Y12 receptor in mediating the pathophysiology of arterial thrombosis. It has been increasingly recognised that platelets also have a critical role in inflammation and immune responses. P2Y12 inhibitors reduce platelet release of pro-inflammatory α-granule contents and the formation of pro-inflammatory platelet-leukocyte aggregates. These are important mediators of inflammation in a variety of different contexts. Clinical evidence shows that P2Y12 inhibition by clopidogrel is associated with a reduction in platelet-related mediators of inflammation, such as soluble P-selectin and CD40L, following atherothrombosis. Clopidogrel in addition to aspirin, compared to aspirin alone, also reduces markers of systemic inflammation such as tumour necrosis factor (TNF) α and C-reactive protein (CRP) following ACS. The more potent thienopyridine P2Y12 inhibitor, prasugrel, has been shown to decrease platelet P-selectin expression and platelet-leukocyte aggregate formation compared to clopidogrel. The PLATO study suggested that the novel P2Y12 inhibitor ticagrelor might improve clinical outcomes from pulmonary infections and sepsis compared to clopidogrel in patients with ACS. Ticagrelor is a more potent P2Y12 inhibitor than clopidogrel and also inhibits cellular adenosine uptake via equilibrative nucleoside transporter (ENT) 1, whereas clopidogrel does not. Further examination of the involvement of these mechanisms in inflammation and immunity is therefore warranted.
Topics: Animals; Anti-Inflammatory Agents; Blood Platelets; Humans; Inflammation; Inflammation Mediators; Platelet Aggregation Inhibitors; Purinergic P2Y Receptor Antagonists; Receptors, Purinergic P2Y12; Signal Transduction
PubMed: 26156883
DOI: 10.1160/TH14-12-1068 -
Molecular Medicine Reports Jan 2021Platelets are small pieces of cytoplasm that have become detached from the cytoplasm of mature megakaryocytes (MKs) in the bone marrow. Platelets modulate vascular... (Review)
Review
Platelets are small pieces of cytoplasm that have become detached from the cytoplasm of mature megakaryocytes (MKs) in the bone marrow. Platelets modulate vascular system integrity and serve important role, particularly in hemostasis. With the rapid development of clinical medicine, the demand for platelet transfusion as a life‑saving intervention increases continuously. Stem cell technology appears to be highly promising for transfusion medicine, and the generation of platelets from stem cells would be of great value in the clinical setting. Furthermore, several studies have been undertaken to investigate the potential of producing platelets from stem cells. Initial success has been achieved in terms of the yields and function of platelets generated from stem cells. However, the requirements of clinical practice remain unmet. The aim of the present review was to focus on several sources of stem cells and factors that induce MK differentiation. Updated information on current research into the genetic regulation of megakaryocytopoiesis and platelet generation was summarized. Additionally, advanced strategies of platelet generation were reviewed and the progress made in this field was discussed.
Topics: Blood Platelets; Cell Culture Techniques; Cell Differentiation; Culture Media; Gene Expression Regulation; Humans; Stem Cells; Thrombopoiesis
PubMed: 33179095
DOI: 10.3892/mmr.2020.11645 -
Transfusion Dec 2019Developments during the past few years have resulted in multiple kinds of platelet products for transfusion. This involves different collection methods, containers,... (Review)
Review
Developments during the past few years have resulted in multiple kinds of platelet products for transfusion. This involves different collection methods, containers, preservative solutions, modifications of storage temperatures and durations, and additional treatments such as pathogen reduction. Much experience has been obtained testing these processes in vitro to seek indications of in vivo effectiveness. Availability of an in vitro method that correlated with in vivo effectiveness would be extremely valuable for these different kinds of platelet products and as more innovation in platelet preparation occurs in the future. This report reviews the methods for in vitro platelet testing with a view to their in vivo implications and whether such testing could be helpful in projecting the clinical effectiveness of different platelet products.
Topics: Blood Platelets; Blood Preservation; Flow Cytometry; Hemostatics; Humans; Microscopy, Electron; Platelet Transfusion
PubMed: 31642072
DOI: 10.1111/trf.15559 -
Platelets Jul 2020Electron microscopy has been a valuable tool for the study of platelet biology and thrombosis for more than 70 years. Early studies using conventional transmission and... (Review)
Review
Electron microscopy has been a valuable tool for the study of platelet biology and thrombosis for more than 70 years. Early studies using conventional transmission and scanning electron microscopy (EM) provided a foundation for our initial understanding of platelet structure and how it changes upon platelet activation. EM approaches have since been utilized to study platelets and thrombi in the context of basic, translational and clinical research, and they are instrumental in the diagnosis of multiple platelet function disorders. In this brief review, we provide a sampling of the many contributions EM based studies have made to the field, including both historical highlights and contemporary applications. We will also discuss exciting new imaging modalities based on EM and their utility for the study of platelets, hemostasis and thrombosis into the future.
Topics: Blood Platelets; Hemostasis; Humans; Microscopy, Electron; Thrombosis
PubMed: 32423268
DOI: 10.1080/09537104.2020.1763939 -
Advances in Experimental Medicine and... 2018Platelets can be considered as the "guardian of hemostasis" where their main function is to maintain vascular integrity. In pathological conditions, the hemostatic role... (Review)
Review
Platelets can be considered as the "guardian of hemostasis" where their main function is to maintain vascular integrity. In pathological conditions, the hemostatic role of platelets may be hijacked to stimulate disease progression. In 1865, Armand Trousseau was a pioneer in establishing the platelet-cancer metastasis relationship, which he eventually termed as Trousseau's Syndrome to describe the deregulation of the hemostasis-associated pathways induced by cancer progression (Varki, Blood. 110(6):1723-9, 2007). Since these early studies, there has been an increase in experimental evidence not only to elucidate the role of platelets in cancer metastasis but also to create novel cancer therapies by targeting the platelet's impact in metastasis. In this chapter, we discuss the contribution of platelets in facilitating tumor cell transit from the primary tumor to distant metastatic sites as well as novel cancer therapies based on platelet interactions.
Topics: Blood Platelets; Drug Delivery Systems; Hemostasis; Humans; Male; Neoplasm Metastasis; Neoplasms
PubMed: 30368756
DOI: 10.1007/978-3-319-95294-9_12 -
International Journal of Molecular... Nov 2019Human pregnancy relies on hemochorial placentation, including implantation of the blastocyst and deep invasion of fetal trophoblast cells into maternal uterine blood... (Review)
Review
Human pregnancy relies on hemochorial placentation, including implantation of the blastocyst and deep invasion of fetal trophoblast cells into maternal uterine blood vessels, enabling direct contact of maternal blood with placental villi. Hemochorial placentation requires fast and reliable hemostasis to guarantee survival of the mother, but also for the neonates. During human pregnancy, maternal platelet count decreases gradually from first, to second, and third trimester. In addition to hemodilution, accelerated platelet sequestration and consumption in the placental circulation may contribute to a decline of platelet count throughout gestation. Local stasis, turbulences, or damage of the syncytiotrophoblast layer can activate maternal platelets within the placental intervillous space and result in formation of fibrin-type fibrinoid. Perivillous fibrinoid is a regular constituent of the normal placenta which is considered to be an important regulator of intervillous hemodynamics, as well as having a role in shaping the developing villous trees. However, exaggerated activation of platelets at the maternal-fetal interface can provoke inflammasome activation in the placental trophoblast, and enhance formation of circulating platelet-monocyte aggregates, resulting in sterile inflammation of the placenta and a systemic inflammatory response in the mother. Hence, the degree of activation determines whether maternal platelets are a friend or foe of the human placenta. Exaggerated activation of maternal platelets can either directly cause or propagate the disease process in placenta-associated pregnancy pathologies, such as preeclampsia.
Topics: Blood Platelets; Female; Hemostasis; Humans; Placenta; Placentation; Pre-Eclampsia; Pregnancy
PubMed: 31718032
DOI: 10.3390/ijms20225639 -
Food and Chemical Toxicology : An... May 2019Hemostasis is a process which encompasses the clotting, fibrinolysis, blood platelet activation and endothelial cell function. Certain dietary components may modulate... (Review)
Review
Hemostasis is a process which encompasses the clotting, fibrinolysis, blood platelet activation and endothelial cell function. Certain dietary components may modulate some elements of hemostasis, particularly blood platelet function, and modify the progression of cardiovascular diseases. The aim of this review paper is to provide an overview of current knowledge of the role of coffee, energy drinks and their bioactive compounds in such modulation. It describes the effect of coffee, energy drinks and their selected components (e.g. caffeine) on hemostasis, especially blood platelets, and their underlying mechanisms. Like coffee, energy drinks may modify platelet reactivity by changing the activity of signaling enzymes, and by modifying cAMP and reactive oxygen species levels. However, the effects of coffee and energy drinks on platelet activation are dependent on a range of factors, including their bioactive components, platelet activators and the methods used for monitoring platelet activation. While some studies (in vivo models) indicate that energy drinks have pro-aggregatory affects, which may be associated with an elevated risk of thrombosis, others indicate that coffee in fact reduces platelet activation, which may be beneficial for prophylaxis of thrombosis.
Topics: Blood Platelets; Cardiovascular Diseases; Coffee; Cyclic AMP; Energy Drinks; Hemostasis; Humans; Platelet Activation; Platelet Aggregation; Reactive Oxygen Species; Signal Transduction
PubMed: 30844438
DOI: 10.1016/j.fct.2019.02.039 -
Platelets Jul 2017Platelets contribute to thrombus formation in a variety of ways. Platelet adhesion, activation, and thrombus growth depend greatly on the type of hemodynamic environment... (Review)
Review
Platelets contribute to thrombus formation in a variety of ways. Platelet adhesion, activation, and thrombus growth depend greatly on the type of hemodynamic environment surrounding an inciting event. Microfluidic systems may be used to explore these relationships. In this review, we describe some important considerations required in the design of a microfluidic system and identify some limitations that may require use of a macroscale system.
Topics: Animals; Blood Platelets; Hemodynamics; Humans; Lab-On-A-Chip Devices; Microfluidic Analytical Techniques; Thrombosis
PubMed: 28594261
DOI: 10.1080/09537104.2017.1316483 -
Blood Reviews Jul 2016In different nucleated cells, NF-κB has long been considered a prototypical proinflammatory signaling pathway with the expression of proinflammatory genes. Although... (Review)
Review
In different nucleated cells, NF-κB has long been considered a prototypical proinflammatory signaling pathway with the expression of proinflammatory genes. Although platelets lack a nucleus, a number of functional transcription factors are involved in activated platelets, such as NF-κB. In platelet activation NF-κB regulation events include IKKβ phosphorylation, IκBα degradation, and p65 phosphorylation. Multiple pathways contribute to platelet activation and NF-κB is a common pathway in this activation. Therefore, in platelet activation the modulation of NF-κB pathway could be a potential new target in the treatment of inflammation-related vascular disease therapy (antiplatelet and antithrombotic activities).
Topics: Blood Platelets; Humans; NF-kappa B; Platelet Activation
PubMed: 27075489
DOI: 10.1016/j.blre.2016.03.002