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Minerva Anestesiologica Jun 2022Platelet activation at the early stage of COVID-19 is poorly described. The need for antiplatelet therapy in patients with COVID-19 remains controversial. We...
BACKGROUND
Platelet activation at the early stage of COVID-19 is poorly described. The need for antiplatelet therapy in patients with COVID-19 remains controversial. We characterized the platelet activation profile in hospitalized patients at the early stage of COVID-19 using the modified prothrombinase Platelet Activation State (PAS) Assay.
METHODS
Sixteen patients admitted to the emergency department of the IRCCS San Raffaele Hospital (Milan, Italy) between February 8 and April 2021 were enrolled. All patients presented with respiratory symptoms and tested positive for severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2). Platelet activation was measured via the PAS Assay within 24 hours from patients' hospital admission. Data were compared with those measured in N.=24 healthy subjects (controls).
RESULTS
Platelet activation was significantly higher in COVID-19 patients with respect to controls (PAS=0.63 [0.58-0.98%] vs. 0.46 [0.40-0.65%], respectively; P=0.03). Of note, highest PAS values were measured in the two patients with the worst clinical outcome, i.e., death because of respiratory failure (PAS=2.09% and 1.20%, respectively). No differences in standard coagulation parameters were noted between these two patients and those who were later discharged home.
CONCLUSIONS
This study provides evidence of significant platelet activation state at the early stage of COVID-19 and suggests that the patient-specific platelet activation profile is a reliable clinical marker to stratify COVID-19 patients at high risk of poor clinical outcome who might potentially benefit from antiplatelet therapy.
Topics: COVID-19; Hospitalization; Humans; Platelet Activation; Platelet Aggregation Inhibitors; SARS-CoV-2
PubMed: 35315619
DOI: 10.23736/S0375-9393.22.16054-2 -
Cirugia Y Cirujanos 2020Platelets, in addition to participating in atherosclerosis, play a very active role in the immune response of this disease since they have the ability to interact with... (Review)
Review
Platelets, in addition to participating in atherosclerosis, play a very active role in the immune response of this disease since they have the ability to interact with various inflammatory cells, in addition to secreting cytokines, chemokines, growth factors, etc. The functions of platelets go beyond their interaction with the endothelium, as they participate in creating an inflammatory environment, which contributes to the loss of homeostasis. On the other hand, platelet-derived microparticles induce the activation of other platelets, of endothelial cells and in recruiting leukocytes. For all the above, platelets and the inflammatory environment can be considered as possible therapeutic targets to prevent the development of atherosclerosis and the events associated with it.
Topics: Atherosclerosis; Cell-Derived Microparticles; Endothelium, Vascular; Humans; Inflammation; Platelet Activation
PubMed: 32116325
DOI: 10.24875/CIRU.19000725 -
International Journal of Molecular... Apr 2024Thrombosis is the pathological clot formation under abnormal hemodynamic conditions, which can result in vascular obstruction, causing ischemic strokes and myocardial... (Review)
Review
Thrombosis is the pathological clot formation under abnormal hemodynamic conditions, which can result in vascular obstruction, causing ischemic strokes and myocardial infarction. Thrombus growth under moderate to low shear (<1000 s) relies on platelet activation and coagulation. Thrombosis at elevated high shear rates (>10,000 s) is predominantly driven by unactivated platelet binding and aggregating mediated by von Willebrand factor (VWF), while platelet activation and coagulation are secondary in supporting and reinforcing the thrombus. Given the molecular and cellular level information it can access, multiscale computational modeling informed by biology can provide new pathophysiological mechanisms that are otherwise not accessible experimentally, holding promise for novel first-principle-based therapeutics. In this review, we summarize the key aspects of platelet biorheology and mechanobiology, focusing on the molecular and cellular scale events and how they build up to thrombosis through platelet adhesion and aggregation in the presence or absence of platelet activation. In particular, we highlight recent advancements in multiscale modeling of platelet biorheology and mechanobiology and how they can lead to the better prediction and quantification of thrombus formation, exemplifying the exciting paradigm of digital medicine.
Topics: Humans; Thrombosis; Blood Platelets; Hemostasis; Platelet Activation; Animals; Platelet Adhesiveness; Platelet Aggregation
PubMed: 38732019
DOI: 10.3390/ijms25094800 -
Journal of Cellular and Molecular... Apr 2020HNG, a highly potent mutant of the anti-Alzheimer peptide-humanin, has been shown to protect against ischaemia-reperfusion (I/R) injury. However, the underlying...
HNG, a highly potent mutant of the anti-Alzheimer peptide-humanin, has been shown to protect against ischaemia-reperfusion (I/R) injury. However, the underlying mechanism related to platelet activation remains unknown. We proposed that HNG has an effect on platelet function and thrombus formation. In this study, platelet aggregation, granule secretion, clot retraction, integrin activation and adhesion under flow conditions were evaluated. In mice receiving HNG or saline, cremaster arterial thrombus formation induced by laser injury, tail bleeding time and blood loss were recorded. Platelet microtubule depolymerization was evaluated using immunofluorescence staining. Results showed that HNG inhibited platelet aggregation, P-selectin expression, ATP release, and α β activation and adhesion under flow conditions. Mice receiving HNG had attenuated cremaster arterial thrombus formation, although the bleeding time was not prolonged. Moreover, HNG significantly inhibited microtubule depolymerization, enhanced tubulin acetylation in platelets stimulated by fibrinogen or microtubule depolymerization reagent, nocodazole, and inhibited AKT and ERK phosphorylation downstream of HDAC6 by collagen stimulation. Therefore, our results identified a novel role of HNG in platelet function and thrombus formation potentially through stabilizing platelet microtubules via tubulin acetylation. These findings suggest a potential benefit of HNG in the management of cardiovascular diseases.
Topics: Adenosine Triphosphate; Animals; Blood Coagulation; Blood Platelets; Histone Deacetylase 6; Humans; Intracellular Signaling Peptides and Proteins; Mice; Microtubules; P-Selectin; Platelet Activation; Platelet Aggregation; Signal Transduction; Thrombosis
PubMed: 32174022
DOI: 10.1111/jcmm.15151 -
Thrombosis Research Sep 2020Traumatic brain injury (TBI) induces acute hypocoagulability, subacute hypercoagulability, and persistently elevated risk for thromboembolic events. Splenectomy is...
INTRODUCTION
Traumatic brain injury (TBI) induces acute hypocoagulability, subacute hypercoagulability, and persistently elevated risk for thromboembolic events. Splenectomy is associated with increased mortality in patients with moderate or severe TBI. We hypothesized that the adverse effects of splenectomy in TBI patients may be secondary to the exacerbation of pathologic coagulation and platelet activation changes.
METHODS
An established murine weight-drop TBI model was utilized and a splenectomy was performed immediately following TBI. Sham as well as TBI and splenectomy alone mice were used as injury controls. Mice were sacrificed for blood draws at 1, 6, and 24 h, as well as 7 days post-TBI. Viscoelastic coagulation parameters were assessed by rotational thromboelastometry (ROTEM) and platelet activation was measured by expression of P-selectin via flow cytometry analysis of platelet rich plasma samples.
RESULTS
At 6 h following injury, TBI/splenectomy demonstrated hypocoagulability with prolonged clot formation time (CFT) compared to TBI alone. By 24 h following injury, TBI/splenectomy and splenectomy mice were hypercoagulable with a shorter CFT, a higher alpha angle, and increased MCF, despite a lower percentage of platelet contribution to clot compared to TBI alone. However, only the TBI/splenectomy continued to display this hypercoagulable state at 7 days. While TBI/splenectomy had greater P-selectin expression at 1-h post-injury, TBI alone had significantly greater P-selectin expression at 24 h post-injury compared to TBI/splenectomy. Interestingly, P-selectin expression remained elevated only in TBI/splenectomy at 7 days post-injury.
CONCLUSION
Splenectomy following TBI exacerbates changes in the post-injury coagulation state. The combination of TBI and splenectomy induces an acute hypocoagulable state that could contribute to an increase in intracranial bleeding. Subacutely, the addition of splenectomy to TBI exacerbates post-injury hypercoagulability and induces persistent platelet activation. These polytrauma effects on coagulation may contribute to the increased mortality observed in patients with combined brain and splenic injuries.
Topics: Animals; Blood Coagulation Disorders; Disease Models, Animal; Humans; Mice; Platelet Activation; Splenectomy; Thrombelastography
PubMed: 32798961
DOI: 10.1016/j.thromres.2020.08.002 -
International Journal of Molecular... Nov 2021Cardiovascular disease is strongly influenced by platelet activation. Platelet activation and thrombus formation at atherosclerotic plaque rupture sites is a dynamic... (Review)
Review
Cardiovascular disease is strongly influenced by platelet activation. Platelet activation and thrombus formation at atherosclerotic plaque rupture sites is a dynamic process regulated by different signaling networks. Therefore, there are now focused efforts to search for novel bioactive compounds which target receptors and pathways in the platelet activation process while preserving normal hemostatic function. The antiplatelet activity of numerous fruits and vegetables and their multiple mechanisms of action have recently been highlighted. In this review, we review the antiplatelet actions of bioactive compounds via key pathways (protein disulfide isomerase, mitogen-activated protein kinases, mitochondrial function, cyclic adenosine monophosphate, Akt, and shear stress-induced platelet aggregation) with no effects on bleeding time. Therefore, targeting these pathways might lead to the development of effective antiplatelet strategies that do not increase the risk of bleeding.
Topics: Animals; Blood Platelets; Hemorrhage; Hemostasis; Humans; Phytochemicals; Plaque, Atherosclerotic; Platelet Activation; Platelet Aggregation; Platelet Aggregation Inhibitors; Thrombosis
PubMed: 34830261
DOI: 10.3390/ijms222212380 -
Middle East African Journal of... 2021The aim of the present study was to assess platelet activation by analyzing three platelet activation parameters in ocular Behçet's disease (BD): mean platelet volume...
PURPOSE
The aim of the present study was to assess platelet activation by analyzing three platelet activation parameters in ocular Behçet's disease (BD): mean platelet volume (MPV), platelet distribution width (PDW), and plateletcrit (PCT).
METHODS
Twenty-nine patients with active ocular BD (Group 1), 40 patients with inactive ocular BD (Group 2), and 40 healthy adult individuals serving as controls (Group 3) were evaluated. All of the individuals had been performed the complete ophthalmologic evaluation. The levels of MPV, PDW, and PCT were measured in each group.
RESULTS
The mean MPV level was 8.40 ± 0.97 in Group 1, 8.32 ± 1.04 in Group 2, and 7.77 ± 0.72 in Group 3. The mean PDW level was 15.12 ± 1.09 in Group 1, 14.97 ± 1.02 in Group 2, and 14.52 ± 0.82 in Group 3. The mean PCT level was 0.23 ± 0.07 in Group 1, 0.21 ± 0.04 in Group 2, and 0.18 ± 0.03 in Group 3. MPV, PDW, and PCT levels were significantly higher in ocular BD patients than controls ( < 0.05).
CONCLUSION
Platelet activation may affect vascular occlusion in ocular Behçet's patients with posterior segment involvement. This result may be important in evaluating ocular BD patients.
Topics: Adult; Behcet Syndrome; Humans; Mean Platelet Volume; Platelet Activation
PubMed: 35719287
DOI: 10.4103/meajo.MEAJO_324_19 -
Oxidative Medicine and Cellular... 2021Recent studies have shown that the red cell distribution width- (RDW-) to-platelet (PLT) count ratio (i.e., RPR) and the mean platelet volume (MPV)/PLT ratio (i.e. MPR)...
OBJECTIVE
Recent studies have shown that the red cell distribution width- (RDW-) to-platelet (PLT) count ratio (i.e., RPR) and the mean platelet volume (MPV)/PLT ratio (i.e. MPR) are more sensitive markers of atherosclerosis-connected risk than RDW and PLT alone. The present study is aimed at investigating the oxidative stress status and these two new markers of platelet activation in two different heart surgery modalities: cardiopulmonary bypass (CPB) and off-pump coronary artery bypass (OPCAB). We also aimed to test the possible relationship between RPR and MPR, respectively, and the severity and complexity of atherosclerotic plaque, measured as Syntax Score. . A total of 107 patients encompassed this prospective study (i.e., 60 patients in CPB group and 47 patients in OPCAB). Blood samples were drawn at several time intervals: before skin incision (t1), immediately after intervention (t2), 6 h (t3), 24 h (t4), 48 h (t5), and 96 h after cessation of the operation (t6).
RESULTS
The values of RPR and MPR were similar in CPB and OPCAB before surgery and started to rise in t2 (i.e., immediately after the intervention). This increase lasted to t5 (i.e., 48 hours after the intervention), when it became the highest. After that, both markers started to regress about the 96 hour after the beginning of surgery. Nominal values of both indices were higher in CPB than in OPCAB in all study points after the surgery. Furthermore, a significantly higher level of antioxidative parameters (i.e., total sulfhydryl groups and paraoxonase 1) in the OPCAB group compared to the CPB group was noted at t5 study point (i.e., 48 hours after the surgery), whereas no significant difference was noted in prooxidant levels (i.e., lipid hydroperoxides and advanced oxidation protein products) between these groups at this study point. MPR and RPR correlated positively with Syntax Score at several study points after the surgery completion. Syntax Score, MPR, and RPR showed good clinical accuracy in surgery-related complication prediction ((AUC = 0.736), 95 CI (0.616-0.856), = 0.003)).
CONCLUSION
When combined, MPV, RDW, and platelet count, such as MPR and RPR, could be good predictors of coronary artery disease status, regarding the aspect of joint inflammation, oxidative stress, and thrombosis.
Topics: Coronary Artery Bypass; Female; Humans; Male; Middle Aged; Oxidative Stress; Platelet Activation
PubMed: 34257821
DOI: 10.1155/2021/8915253 -
Blood Reviews Sep 2019Platelets play a major role in primary hemostasis and thrombus formation. After vascular injury, platelets adhere to injured site and rapidly change their shape that... (Review)
Review
Platelets play a major role in primary hemostasis and thrombus formation. After vascular injury, platelets adhere to injured site and rapidly change their shape that switches the resting platelets to active state. Activated platelets aggregate and secrete biologically active intermediate substances that further potentiate platelet activation through autocrine as well as paracrine mechanisms. The activated platelet expresses certain proteins that are not seen on the resting platelets, thus these proteins serve as markers of platelet activation. Other subsequent events of platelet activation include release of microvesicles and formation of complexes with other circulating cells, like monocytes and neutrophils. Platelet activation markers are useful tools in evaluating risk factors of thrombosis in a variety of clinical conditions. Increased platelet activation has been associated with various pathological conditions such as acute coronary syndrome, stroke, peripheral vascular disease and other inflammatory diseases. The advancement in technologies helps in determining the status of platelet activation in such clinical conditions. This article focuses on the sources, mechanism and diagnosis of platelet activation and their clinical implications.
Topics: Humans; Platelet Activation; Risk Factors; Thrombosis
PubMed: 31133440
DOI: 10.1016/j.blre.2019.05.007 -
Journal of Thrombosis and Haemostasis :... Feb 2022Platelet activation and thrombotic events characterizes COVID-19.
BACKGROUND
Platelet activation and thrombotic events characterizes COVID-19.
OBJECTIVES
To characterize platelet activation and determine if SARS-CoV-2 induces platelet activation.
PATIENTS/METHODS
We investigated platelet activation in 119 COVID-19 patients at admission in a university hospital in Milan, Italy, between March 18 and May 5, 2020. Sixty-nine subjects (36 healthy donors, 26 patients with coronary artery disease, coronary artery disease, and seven patients with sepsis) served as controls.
RESULTS
COVID-19 patients had activated platelets, as assessed by the expression and distribution of HMGB1 and von Willebrand factor, and by the accumulation of platelet-derived (plt) extracellular vesicles (EVs) and HMGB1 plt-EVs in the plasma. P-selectin upregulation was not detectable on the platelet surface in a fraction of patients (55%) and the concentration of soluble P-selectin in the plasma was conversely increased. The plasma concentration of HMGB1 plt-EVs of patients at hospital admission remained in a multivariate analysis an independent predictor of the clinical outcome, as assessed using a 6-point ordinal scale (from 1 = discharged to 6 = death). Platelets interacting in vitro with SARS-CoV-2 underwent activation, which was replicated using SARS-CoV-2 pseudo-viral particles and purified recombinant SARS-CoV-2 spike protein S1 subunits. Human platelets express CD147, a putative coreceptor for SARS-CoV-2, and Spike-dependent platelet activation, aggregation and granule release, release of soluble P-selectin and HMGB1 plt-EVs abated in the presence of anti-CD147 antibodies.
CONCLUSIONS
Hence, an early and intense platelet activation, which is reproduced by stimulating platelets in vitro with SARS-CoV-2, characterizes COVID-19 and could contribute to the inflammatory and hemostatic manifestations of the disease.
Topics: Blood Platelets; COVID-19; Humans; Platelet Activation; SARS-CoV-2; Spike Glycoprotein, Coronavirus
PubMed: 34710269
DOI: 10.1111/jth.15575