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Platelets Dec 2023
Topics: Humans; Blood Platelets
PubMed: 37126352
DOI: 10.1080/09537104.2023.2204619 -
Thrombosis Research Nov 2023Platelet ageing is an area of research which has gained much interest in recent years. Newly formed platelets, often referred to as reticulated platelets, young... (Review)
Review
Platelet ageing is an area of research which has gained much interest in recent years. Newly formed platelets, often referred to as reticulated platelets, young platelets or immature platelets, are defined as RNA-enriched and have long been thought to be hyper-reactive. This latter view is largely rooted in associations and observations in patient groups with shortened platelet half-lives who often present with increased proportions of newly formed platelets. Evidence from such groups suggests that an increased proportion of newly formed platelets is associated with an increased risk of thrombotic events and a reduced effectiveness of standard anti-platelet therapies. Whilst research has highlighted the existence of platelet subpopulations based on function, size and age within patient groups, the common intrinsic changes which occur as platelets age within the circulation are only just being explored. By understanding the changes that occur during the natural ageing processes of platelets, we may be able to identify the triggers for alterations in platelet life span and platelet reactivity. Here we review research on platelet ageing in the context of health and disease, paying particular attention to the experimental approaches taken and the robustness of conclusions that can be drawn.
Topics: Humans; Blood Platelets; Aging
PubMed: 36587993
DOI: 10.1016/j.thromres.2022.12.004 -
Current Opinion in Hematology Sep 2023Platelet mitochondrial dysfunction is both caused by, as well as a source of oxidative stress. Oxidative stress is a key hallmark of metabolic disorders such as... (Review)
Review
PURPOSE OF REVIEW
Platelet mitochondrial dysfunction is both caused by, as well as a source of oxidative stress. Oxidative stress is a key hallmark of metabolic disorders such as dyslipidemia and diabetes, which are known to have higher risks for thrombotic complications.
RECENT FINDINGS
Increasing evidence supports a critical role for platelet mitochondria beyond energy production and apoptosis. Mitochondria are key regulators of reactive oxygen species and procoagulant platelets, which both contribute to pathological thrombosis. Studies targeting platelet mitochondrial pathways have reported promising results suggesting antithrombotic effects with limited impact on hemostasis in animal models.
SUMMARY
Targeting platelet mitochondria holds promise for the reduction of thrombotic complications in patients with metabolic disorders. Future studies should aim at validating these preclinical findings and translate them to the clinic.
Topics: Animals; Humans; Blood Platelets; Mitochondria; Oxidative Stress; Reactive Oxygen Species; Hemostasis; Thrombosis
PubMed: 37459354
DOI: 10.1097/MOH.0000000000000772 -
Blood Jan 2024
Topics: Blood Platelets
PubMed: 38175681
DOI: 10.1182/blood.2023022346 -
British Journal of Pharmacology Feb 2024This article is part of a themed issue on Platelet purinergic receptor and non-thrombotic disease. To view the other articles in this section visit...
This article is part of a themed issue on Platelet purinergic receptor and non-thrombotic disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.4/issuetoc.
Topics: Receptors, Purinergic; Blood Platelets; Humans
PubMed: 38093587
DOI: 10.1111/bph.16290 -
Thrombosis Research Nov 2023Platelets are major regulators of haemostasis and coagulation. The primary role of platelets in coagulation is to form a stable clot and stop bleeding. Studies of... (Review)
Review
Platelets are major regulators of haemostasis and coagulation. The primary role of platelets in coagulation is to form a stable clot and stop bleeding. Studies of platelet phenotype and function in neonates and children have been restricted by the large volumes required for many common platelet function tests such as platelet aggregometry. Developmental changes in platelets have not been as well described as developmental changes in plasma coagulation proteins, and overall, platelet phenotype and function in neonates and children has been understudied when compared to adults. Recent developments in more sensitive platelet function testing methods requiring smaller blood volumes such as flow cytometry has enabled recent studies to further investigate platelet phenotype and function in neonates and children. In this review we will provide an overview of recent advances from the past five years in platelets in the context of developmental haemostasis, as well as the role of platelets in neonatal paediatric disease.
Topics: Infant, Newborn; Adult; Child; Humans; Platelet Aggregation; Blood Platelets; Hemostasis; Platelet Function Tests; Blood Coagulation
PubMed: 36997443
DOI: 10.1016/j.thromres.2023.03.005 -
Blood Feb 2024In humans, ∼0.1% to 0.3% of circulating red blood cells (RBCs) are present as platelet-RBC (P-RBC) complexes, and it is 1% to 2% in mice. Excessive P-RBC complexes are...
In humans, ∼0.1% to 0.3% of circulating red blood cells (RBCs) are present as platelet-RBC (P-RBC) complexes, and it is 1% to 2% in mice. Excessive P-RBC complexes are found in diseases that compromise RBC health (eg, sickle cell disease and malaria) and contribute to pathogenesis. However, the physiological role of P-RBC complexes in healthy blood is unknown. As a result of damage accumulated over their lifetime, RBCs nearing senescence exhibit physiological and molecular changes akin to those in platelet-binding RBCs in sickle cell disease and malaria. Therefore, we hypothesized that RBCs nearing senescence are targets for platelet binding and P-RBC formation. Confirming this hypothesis, pulse-chase labeling studies in mice revealed an approximately tenfold increase in P-RBC complexes in the most chronologically aged RBC population compared with younger cells. When reintroduced into mice, these complexes were selectively cleared from the bloodstream (in preference to platelet-free RBC) through the reticuloendothelial system and erythrophagocytes in the spleen. As a corollary, patients without a spleen had higher levels of complexes in their bloodstream. When the platelet supply was artificially reduced in mice, fewer RBC complexes were formed, fewer erythrophagocytes were generated, and more senescent RBCs remained in circulation. Similar imbalances in complex levels and senescent RBC burden were observed in humans with immune thrombocytopenia (ITP). These findings indicate that platelets are important for binding and clearing senescent RBCs, and disruptions in platelet count or complex formation and clearance may negatively affect RBC homeostasis and may contribute to the known risk of thrombosis in ITP and after splenectomy.
Topics: Humans; Animals; Mice; Aged; Blood Platelets; Erythrocytes; Thrombocytopenia; Anemia, Sickle Cell; Malaria
PubMed: 37992231
DOI: 10.1182/blood.2023021611 -
Current Opinion in Hematology Jan 2024Activated or aged platelets are removed from circulation under (patho)physiologic conditions, the exact mechanism of platelet clearance under such conditions remains... (Review)
Review
PURPOSE OF REVIEW
Activated or aged platelets are removed from circulation under (patho)physiologic conditions, the exact mechanism of platelet clearance under such conditions remains unclear and are currently being investigated. This review focuses on recent findings and controversies regarding platelet clearance and the disruption of platelet life cycle.
RECENT FINDINGS
The platelet life span is determined by glycosylation of platelet surface receptors with sialic acid. Recently, it was shown that platelet activation and granule release leads to desialylation of glycans and accelerated clearance of platelets under pathological conditions. This phenomenon was demonstrated to be a main reason for thrombocytopenia being a complication in several infections and immune disorders.
SUMMARY
Although we have recently gained some insight into how aged platelets are cleared from circulation, we are still not seeing the full picture. Further investigations of the platelet clearance pathways under pathophysiologic conditions are needed as well as studies to unravel the connection between platelet clearance and platelet production.
Topics: Aged; Humans; Blood Platelets; N-Acetylneuraminic Acid; Polysaccharides; Thrombocytopenia; Cellular Senescence; Cytophagocytosis
PubMed: 37905750
DOI: 10.1097/MOH.0000000000000792 -
Periodontology 2000 Feb 2024The use of platelet-rich fibrin (PRF) has gained tremendous popularity in recent years owing to its ability to speed wound healing postsurgery. However, to date, many... (Review)
Review
The use of platelet-rich fibrin (PRF) has gained tremendous popularity in recent years owing to its ability to speed wound healing postsurgery. However, to date, many clinicians are unaware of methods designed to optimize the technology. This overview article will discuss the advancements and improvements made over the years aimed at maximizing cell and growth factor concentrations. First, a general understanding explaining the differences between RPM and RCF (g-force) is introduced. Then, the low-speed centrifugation concept, fixed angle versus horizontal centrifugation, and methods to maximize platelet concentrations using optimized protocols will be discussed in detail. Thereafter, the importance of chemically modified PRF tubes without the addition of chemical additives, as well as regulation of temperature to induce/delay clotting, will be thoroughly described. This article is a first of its kind summarizing all recent literature on PRF designed to optimize PRF production for clinical treatment.
Topics: Humans; Platelet-Rich Fibrin; Centrifugation; Wound Healing; Blood Platelets; Intercellular Signaling Peptides and Proteins; Platelet Count; Blood Coagulation
PubMed: 37681522
DOI: 10.1111/prd.12521 -
Clinics in Laboratory Medicine Sep 2023Clinical flow cytometry tests for inherited and acquired platelet disorders are useful diagnostic tools but are not widely available. Flow cytometric methods are... (Review)
Review
Clinical flow cytometry tests for inherited and acquired platelet disorders are useful diagnostic tools but are not widely available. Flow cytometric methods are available to detect inherited glycoprotein deficiencies, granule release (secretion defects), drug-induced thrombocytopenias, presence of antiplatelet antibodies, and pharmacodynamic inhibition by antiplatelet agents. New tests take advantage of advanced multicolor cytometers and allow identification of novel platelet subsets by high-dimensional immunophenotyping. Studies are needed to evaluate the value of these new tests for diagnosis and monitoring of therapy in patients with platelet disorders.
Topics: Humans; Blood Platelets; Blood Platelet Disorders; Antibodies; Flow Cytometry; Immunophenotyping
PubMed: 37481322
DOI: 10.1016/j.cll.2023.04.008