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1.
JCO Precis Oncol ; 6: e2200237, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36108260

RESUMO

PURPOSE: Ado-trastuzumab emtansine (T-DM1) treatment results in grade 3-4 thrombocytopenia in 8%-13% of patients. Prior in vitro studies reported T-DM1 inhibition of megakaryocyte maturation as the cause of decreased platelet production. The current observational study was initiated to evaluate causes of thrombocytopenia in patients with metastatic breast cancer. MATERIALS AND METHODS: Patients with human epidermal growth factor receptor 2-positive metastatic breast cancer (N = 11) were enrolled in this postmarket safety study. 111-Indium- radiolabeled autologous platelet recoveries and survivals as well as serial platelet counts, bleeding time assays, and platelet aggregation responses to a wide range of agonists were performed at baseline (BL) and during two consecutive cycles of the drug (3.6 mg/kg IV once every 3 weeks). RESULTS: Platelet nadirs occurred earlier in cycle 2 than in cycle 1. Average nadir counts (% BL) in cycles 1 and 2 were 116,000/µL (53% ± 6%) and 115,000/µL (51% ± 9%), respectively, with return to BL by D15 in both cycles. BL platelet survival averaged 8.8 (± 0.3) days but progressively shortened to 5.5 (± 0.5) days during cycle 1 and to 4.6 (± 0.3) days during cycle 2 (P < .001 compared with BL for both cycles). Aggregation responses to all agonists decreased during the study, both in cycle 1 and cycle 2. CONCLUSION: Following T-DM1 administration, we observed statistically significant progressive decreases in platelet survivals and decreased platelet function from BL values. In distinction to published in vitro studies, these unexpected results indicate a direct toxic effect of T-DM1 on patients' autologous circulating platelets.


Assuntos
Neoplasias da Mama , Maitansina , Trombocitopenia , Ado-Trastuzumab Emtansina , Anticorpos Monoclonais Humanizados/farmacologia , Plaquetas/metabolismo , Neoplasias da Mama/tratamento farmacológico , Feminino , Humanos , Índio/uso terapêutico , Cinética , Maitansina/farmacologia , Receptor ErbB-2 , Trombocitopenia/tratamento farmacológico , Trastuzumab/farmacologia
2.
Int J Mol Sci ; 23(17)2022 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-36077280

RESUMO

Antiplatelet therapy aims to reduce the risk of thrombotic events while maintaining hemostasis. A promising current approach is the inhibition of platelet glycoprotein GPVI-mediated adhesion pathways; pathways that do not involve coagulation. GPVI is a signaling receptor integral for collagen-induced platelet activation and participates in the thrombus consolidation process, being a suitable target for thrombosis prevention. Considering this, the blocking or antibody-mediated depletion of GPVI is a promising antiplatelet therapy for the effective and safe treatment of thrombotic diseases without a significant risk of bleeding and impaired hemostatic plug formation. This review describes the current knowledge concerning pharmaceutical approaches to platelet GPVI modulation and its downstream signaling pathways in this context.


Assuntos
Inibidores da Agregação Plaquetária , Trombose , Plaquetas/metabolismo , Humanos , Ativação Plaquetária , Inibidores da Agregação Plaquetária/metabolismo , Inibidores da Agregação Plaquetária/farmacologia , Inibidores da Agregação Plaquetária/uso terapêutico , Glicoproteínas da Membrana de Plaquetas/metabolismo , Transdução de Sinais , Trombose/metabolismo
3.
Oxid Med Cell Longev ; 2022: 1898844, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36046681

RESUMO

Platelet transfusion is a life-saving therapy to prevent bleeding; however, the availability of platelets for transfusion is limited by the markedly short shelf life owing to the development of platelet storage lesions (PSLs). The mechanism of PSLs remains obscure. Dissection of the intracellular biological changes in stored platelets may help to reduce PSLs and improve platelet transfusion efficiency. In the present study, we explore the changes of stored platelets at room temperature under constant agitation. We found that platelets during storage showed an increased reactive oxygen species (ROS) generation accompanied with receptor shedding, apoptosis, and diminished platelet aggregation. ROS scavenger reduced platelet shedding but also impaired platelet aggregation. Autophagy is a conserved catabolic process that sequesters protein aggregates and damaged organelles into lysosomes for degradation and platelets' own intact autophagic system. We revealed that there exist a stable autophagic flux in platelets at the early stage of storage, and the autophagic flux in platelets perished after long-term storage. Treatment stored platelets with rapamycin, which stimulates autophagy in eukaryotic cells, markedly ameliorated PSLs, and improved platelet aggregation in response to extracellular stimuli.


Assuntos
Plaquetas , Agregação Plaquetária , Autofagia , Plaquetas/metabolismo , Transfusão de Plaquetas , Espécies Reativas de Oxigênio/metabolismo
4.
Int J Lab Hematol ; 44 Suppl 1: 89-100, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36074709

RESUMO

Platelet procoagulant mechanisms are emerging to be complex and important to achieving haemostasis. The mechanisms include the release of procoagulant molecules from platelet storage granules, and strong agonist-induced expression of procoagulant phospholipids on the outer platelet membrane for tenase and prothrombinase assembly. The release of dense granule polyphosphate is important to platelet procoagulant function as it promotes the activation of factors XII, XI and V, inhibits tissue factor pathway inhibitor and fibrinolysis, and strengthens fibrin clots. Platelet procoagulant function also involves the release of partially activated factor V from platelets. Scott syndrome has provided important insights on the mechanisms that regulate procoagulant phospholipids expression on the external platelet membrane, which require strong agonist stimulation that increase cystolic calcium levels, mitochondrial calcium uptake, the loss of flippase function and activation of the transmembrane scramblase protein anoctamin 6. There have been advances in the methods used to directly and indirectly assess platelet procoagulant function in health and disease. Assessments of thrombin generation with platelet rich plasma samples has provided new insights on how platelet procoagulant function is altered in inherited platelet disorders, and how platelets influence the bleeding phenotype of a number of severe coagulation factor deficiencies. Several therapies, including desmopressin and recombinant factor VIIa, improve thrombin generation by platelets. There is growing interest in targeting platelet procoagulant function for therapeutic benefit. This review highlights recent advances in our understanding of platelet-dependent procoagulant mechanisms in health and in bleeding disorders.


Assuntos
Transtornos da Coagulação Sanguínea , Transtornos Hemorrágicos , Plaquetas/metabolismo , Cálcio/metabolismo , Humanos , Fosfolipídeos/metabolismo , Ativação Plaquetária , Trombina/metabolismo
5.
PLoS One ; 17(8): e0267833, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36044519

RESUMO

BACKGROUND: The main inhibitor of the fibrinolytic system, Plasminogen Activator Inhibitor -1 (PAI-1), irreversibly binds tissue-type Plasminogen Activator (t-PA) and thereby inhibits the protective action of tPA against thrombus formation. Elevated levels of plasma PAI-1 are associated with an increased risk of cardiovascular events and are observed in subjects with type 2 diabetes (T2D) and obesity. Platelets contain the majority of PAI-1 present in blood and exhibit the ability to synthesis active PAI-1. Diabetic platelets are known to be hyper-reactive and larger in size; however, whether these features affect their contribution to the elevated levels of plasma PAI-1 in T2D is not established. OBJECTIVES: To characterize the PAI-1 antigen content and the mRNA expression in platelets from T2D subjects compared to obese and lean control subjects, in order to elucidate the role of platelet PAI-1 in T2D. METHODS: Nine subjects with T2D and obesity were recruited from Primary Care Centers together with 15 healthy control subjects (8 lean subjects and 7 with obesity). PAI-1 antigen levels in plasma, serum and platelets were determined by ELISA, and PAI-1 mRNA expression was analyzed by qPCR. RESULTS: There was no significant difference in PAI-1 mRNA expression or PAI-1 antigen in platelets in T2D subject in comparison to obese and lean control subjects. An elevated level of plasma PAI-1 was seen in both T2D and obese subjects. PAI-1 gene expression was significantly higher in both obese groups compared to lean. CONCLUSION: Similar levels of protein and mRNA expression of PAI-1 in platelets from T2D, obese and lean subjects indicate a limited role of platelets for the elevated plasma PAI-1 levels. However, an increased synthesis rate of mRNA transcripts in platelets from T2D and an increased release of PAI-1 could also result in similar mRNA and protein levels. Hence, synthesis and release rates of PAI-1 from platelets in T2D and obesity need to be investigated to further elucidate the role of platelets in obesity and T2D.


Assuntos
Diabetes Mellitus Tipo 2 , Inibidor 1 de Ativador de Plasminogênio , Plaquetas/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Obesidade , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Inibidor 2 de Ativador de Plasminogênio/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ativador de Plasminogênio Tecidual/metabolismo
6.
Mech Ageing Dev ; 207: 111725, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35995275

RESUMO

Alzheimer's disease (AD) is an evolving challenge that places an enormous burden on families and society. The presence of obvious brain ß-amyloid (Aß) deposition is a premise to diagnose AD, which induces the subsequent tau hyperphosphorylation and neurodegeneration. Platelets are the primary source of circulating amyloid precursor protein (APP). Upon activation, they can secrete significant amounts of Aß into the blood, which can be actively transported to the brain across the blood-brain barrier and promote amyloid deposition. In this review, we summarized the changes in the platelet APP metabolic pathway in patients with AD and further comprehensively explored the targets and downstream events of Aß-activated platelets. In addition, we attempted to clarify whether patients with AD are in a state of general platelet activation, with inconsistent results. Considering the increasingly evident bidirectional relationship between AD and vascular events, we speculate that the AD pathology alone seems to be insufficient to induce the general activation of platelets; however, the intervention of third-party factors, such as atherosclerosis, exposes the extracellular matrix and leads to platelet activation, further promoting AD progression. Therefore, we proposed a framework in which the relationship between platelets and AD is indirect and mediated by vascular factors. Therapies targeting platelets and interventions for vascular risk factors are likely to contribute to the prevention and treatment of AD.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Plaquetas/metabolismo , Plaquetas/patologia , Humanos , Ativação Plaquetária , Fatores de Risco
7.
Cells ; 11(16)2022 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-36010639

RESUMO

Despite fully functional primary hemostasis, platelets of healthy neonates exhibit hypoaggregability and secretion defects, which may be adaptations to specific requirements in this developmental stage. The etiologies for reduced signal transduction vary with the type of agonist. The discovered peculiarities are lower receptor densities, reduced calcium mobilization, and functional impairments of G proteins. Reduced secretion of dense granules has been attributed to lower numbers of granules. Signaling studies with adult platelets have shown a regulating effect of the G12/13 signaling pathway on dense granule secretion via RhoA. We comparatively analyzed secretion profiles using flow cytometry and expression levels of Gq, Gi, and G12/13 using Western blot analysis in platelets from cord blood and adults. Furthermore, we evaluated Rho activation after in vitro platelet stimulation with thrombin using a pulldown assay. We observed a markedly reduced expression of the dense granule marker CD63 on neonatal platelets after thrombin stimulation. Gα12/13 expression was significantly decreased in neonatal platelets and correlated with lower Rho activation after thrombin stimulation. We conclude that lower expression of G12/13 in neonatal platelets results in attenuated activation of Rho and may contribute to reduced secretion of dense granules after exposure to thrombin.


Assuntos
Plaquetas , Subunidades alfa G12-G13 de Proteínas de Ligação ao GTP/metabolismo , Trombina , Plaquetas/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Hemostasia , Humanos , Recém-Nascido , Transdução de Sinais , Trombina/farmacologia
8.
Int J Mol Sci ; 23(16)2022 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-36012465

RESUMO

Dyslipidaemia leads to proatherogenic oxidative lipid stress that promotes vascular inflammation and thrombosis, the pathologies that underpin myocardial infarction, stroke, and deep vein thrombosis. These prothrombotic states are driven, at least in part, by platelet hyperactivity, and they are concurrent with the appearancxe of oxidatively modified low-density lipoproteins (LDL) in the circulation. Modified LDL are heterogenous in nature but, in a general sense, constitute a prototype circulating transporter for a plethora of oxidised lipid epitopes that act as danger-associated molecular patterns. It is well-established that oxidatively modified LDL promote platelet activation and arterial thrombosis through a number of constitutively expressed scavenger receptors, which transduce atherogenic lipid stress to a complex array of proactivatory signalling pathways in the platelets. Stimulation of these signalling events underlie the ability of modified LDL to induce platelet activation and blunt platelet inhibitory pathways, as well as promote platelet-mediated coagulation. Accumulating evidence from patients at risk of arterial thrombosis and experimental animal models of disease suggest that oxidised LDL represents a tangible link between the dyslipidaemic environment and increased platelet activation. The aim of this review is to summarise recent advances in our understanding of the pro-thrombotic signalling events induced in platelets by modified LDL ligation, describe the contribution of individual platelet scavenger receptors, and highlight potential future challenges of targeting these pathways.


Assuntos
Dislipidemias , Trombose , Animais , Coagulação Sanguínea , Plaquetas/metabolismo , Dislipidemias/metabolismo , Lipoproteínas LDL/metabolismo , Ativação Plaquetária , Trombose/metabolismo
9.
Shock ; 58(1): 1-13, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35984758

RESUMO

ABSTRACT: Platelets are subcellular anucleate components of blood primarily responsible for initiating and maintaining hemostasis. After injury to a blood vessel, platelets can be activated via several pathways, resulting in changed shape, adherence to the injury site, aggregation to form a plug, degranulation to initiate activation in other nearby platelets, and acceleration of thrombin formation to convert fibrinogen to fibrin before contracting to strengthen the clot. Platelet function assays use agonists to induce and measure one or more of these processes to identify alterations in platelet function that increase the likelihood of bleeding or thrombotic events. In severe trauma, these assays have revealed that platelet dysfunction is strongly associated with poor clinical outcomes. However, to date, the mechanism(s) causing clinically significant platelet dysfunction remain poorly understood. We review the pros, cons, and evidence for use of many of the popular assays in trauma, discuss limitations of their use in this patient population, and present approaches that can be taken to develop improved functional assays capable of elucidating mechanisms of trauma-induced platelet dysfunction. Platelet dysfunction in trauma has been associated with need for transfusions and mortality; however, most of the current platelet function assays were not designed for evaluating trauma patients, and there are limited data regarding their use in this population. New or improved functional assays will help define the mechanisms by which platelet dysfunction occurs, as well as help optimize future treatment.


Assuntos
Plaquetas , Hemostasia , Trombose , Ferimentos e Lesões , Plaquetas/metabolismo , Fibrina/metabolismo , Hemostasia/fisiologia , Humanos , Agregação Plaquetária , Testes de Função Plaquetária/métodos , Ferimentos e Lesões/metabolismo
10.
Int J Mol Sci ; 23(16)2022 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-36012752

RESUMO

During ischemic stroke, infarct growth before recanalization diminishes functional outcome. Hence, adjunct treatment options to protect the ischemic penumbra before recanalization are eagerly awaited. In experimental stroke targeting two different pathways conferred protection from penumbral tissue loss: (1) enhancement of hypoxic tolerance of neurons by deletion of the calcium channel subunit Orai2 and (2) blocking of detrimental lymphocyte-platelet responses. However, until now, no preclinical stroke study has assessed the potential of combining neuroprotective with anti-thrombo-inflammatory interventions to augment therapeutic effects. We induced focal cerebral ischemia in Orai2-deficient (Orai2-/-) mice by middle cerebral artery occlusion (MCAO). Animals were treated with anti-glycoprotein Ib alpha (GPIbα) Fab fragments (p0p/B Fab) blocking GPIbα-von Willebrand factor (vWF) interactions. Rat immunoglobulin G (IgG) Fab was used as the control treatment. The extent of infarct growth before recanalization was assessed at 4 h after MCAO. Moreover, infarct volumes were determined 6 h after recanalization (occlusion time: 4 h). Orai2 deficiency significantly halted cerebral infarct progression under occlusion. Inhibition of platelet GPIbα further reduced primary infarct growth in Orai2-/- mice. During ischemia-reperfusion, upon recanalization, mice were likewise protected. All in all, we show that neuroprotection in Orai2-/- mice can be augmented by targeting thrombo-inflammation. This supports the clinical development of combined neuroprotective/anti-platelet strategies in hyper-acute stroke.


Assuntos
Isquemia Encefálica , Proteína ORAI2 , Acidente Vascular Cerebral , Animais , Plaquetas/metabolismo , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/genética , Isquemia Encefálica/prevenção & controle , Modelos Animais de Doenças , Infarto da Artéria Cerebral Média/metabolismo , Camundongos , Camundongos Knockout , Neuroproteção , Proteína ORAI2/genética , Acidente Vascular Cerebral/metabolismo
11.
Life Sci ; 306: 120855, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35926591

RESUMO

Alzheimer's disease (AD), a progressive neurodegenerative disorder, is considered one of the most common causes of dementia worldwide, accounting for about 80 % of all dementia cases. AD is manifested by the extraneuronal deposition of senile plaques of amyloid beta (Aß) and intraneuronal accumulation of neurofibrillary tangles of phosphorylated tau. The impaired proteostasis of these filamentous Aß and tau is significantly regulated by reactive oxygen species (ROS). ROS-induced oxidative stress (OS) is the cardinal cause behind neuroinflammation-triggered neurodegeneration during AD. Besides ROS-induced neuro-inflammation, AD is also associated with cerebrovascular dysfunction, where platelet primarily plays a significant role in blood-vessel integrity and tissue repair. Though platelets are the circulatory cell fragments that play predominant roles in thrombosis and hemostasis, their contributions to other physiological functions are also being elucidated. Surprisingly, platelets contribute about 90 % of the circulatory Aß and share striking similarities with neurons in several aspects, including different neurotransmitters and their cognate receptors, thus considering platelets as potential peripheral models for AD. Interestingly, platelet structural and functional dysfunctions are evident in AD, where ROS production is associated with platelet hyperactivity. Although activated platelet carries several vital enzymes and immunomodulatory molecules, which can potentially exacerbate OS-mediated neuronal damage, and neurodegeneration, their mechanism of action and mode of progression, are still obscure. Therefore, in this review, we have described the detailed role of OS and platelet in AD, addressing the therapeutic approach and molecular mechanism of platelet-mediated ROS generation as a contributing factor in aggravating the disease.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides/metabolismo , Plaquetas/metabolismo , Humanos , Estresse Oxidativo , Espécies Reativas de Oxigênio
12.
Transfusion ; 62(9): 1882-1893, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35929193

RESUMO

BACKGROUND: Female sex confers a survival advantage following severe injury in the setting of trauma-induced coagulopathy, with female platelets having heightened responsiveness likely due to estrogen. The effects of testosterone on platelet biology are unknown, and platelets express both estradiol and androgen receptors on the plasma membrane. We hypothesize testosterone decreases platelet responses in vitro, and there are baseline differences in platelet function and metabolism stratified by sex/age. STUDY DESIGN AND METHODS: Apheresis platelets were collected from: older males (OM) ≥45 years, younger males (YM) <45 years, older females (OF) ≥54 years, and younger females (YF) <54 years, and testosterone and estradiol were measured. Platelets were incubated with testosterone (5.31 ng/ml), estradiol (105 pg/ml) or vehicle and stimulated with buffer, adenosine diphosphate (20 µM), platelet activating factor (2 µM), or thrombin (0.3 U/ml). Aggregation, CD62P surface expression, fibrinogen receptor surface expression, and platelet mitochondrial metabolism were measured. RESULTS: Testosterone significantly inhibited aggregation in OF and OM (p < .05), inhibited CD41a expression in YF, YM, and OM (p < .05), and affected a few of the baseline amounts of CD62P surface expression but not platelet activation to platelet-activating factor and adenosine diphosphate, and variably changed platelet metabolism. DISCUSSION: Platelets have sex- and age-specific aggregation, receptor expression, and metabolism. Testosterone decreases platelet function dependent on the stimulus, age, and sex. Similarly, platelet metabolism has varying responses to sex hormones with baseline metabolic differences dependent upon sex and age.


Assuntos
Plaquetas , Agregação Plaquetária , Difosfato de Adenosina/farmacologia , Plaquetas/metabolismo , Estradiol/metabolismo , Estradiol/farmacologia , Feminino , Humanos , Masculino , Testosterona/farmacologia
13.
Cytokine ; 158: 155969, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35930963

RESUMO

BACKGROUND: The study explored the role of platelet TGF-ß1 from the perspective of inhibiting the excessive proliferation, migration and invasion of murine aortic vascular smooth muscle cells (MASMCs). METHOD: The platelets were first extracted from C57BL/6 mice, and the TGF-ß1 protein was obtained after the purification of protein. In vitro, the concentrations of angiotensin Ⅱ (Ang Ⅱ) and TGF-ß1 for intervention were screened by testing the viability of MASMCs, followed by the analysis concerning the effects of platelets, Ang Ⅱ and TGF-ß1 on the proliferation, migration, invasion, and the expressions of pathway-related proteins in MASMCs. In vivo, an Ang Ⅱ-induced mouse model was established. TGF-ß1 was injected into the tail of mice as a therapeutic agent, and its action mechanism was further verified by the treatment of inhibitor SB505124. The results of the cell experiment were validated by evaluating the maximum diameter of abdominal aorta, the proportion of total weight, the changes of both pathology and the expressions of pathway-related proteins in the mice. RESULT: 0.5 ng/mL Ang Ⅱ and 15 ng/mL TGF-ß1 were chosen for treatment. The following results of cell functional experiments and Western blot assay demonstrated that Ang Ⅱ promoted the proliferation, migration and invasion of MASMCs via regulating related pathways, the effects of which were evidently reversed by TGF-ß1 and platelets. Consistent results were also observed in the animal experiments, where TGF-ß1 effectively alleviated Ang Ⅱ-induced abdominal aortic injury in mice. CONCLUSION: TGF-ß1 in platelets inhibits Ang Ⅱ-induced proliferation, migration and invasion of MASMCs.


Assuntos
Aneurisma , Fator de Crescimento Transformador beta1 , Aneurisma/metabolismo , Angiotensina II/metabolismo , Angiotensina II/farmacologia , Animais , Aorta Abdominal/metabolismo , Plaquetas/metabolismo , Proliferação de Células , Camundongos , Camundongos Endogâmicos C57BL , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Fator de Crescimento Transformador beta1/metabolismo
14.
Curr Pharm Des ; 28(21): 1745-1757, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35986552

RESUMO

Cardiovascular disease remains the main cause of human morbidity and mortality in developed countries. Microparticles (MPs) are small vesicles originating from the cell membrane as a result of various stimuli and particularly of biological processes that constitute the pathophysiology of atherosclerosis, such as endothelial damage. They form vesicles that can transfer various molecules and signals to remote target cells without direct cell-to-cell interaction. Circulating microparticles have been associated with cardiovascular diseases. Therefore, many studies have been designed to further investigate the role of microparticles as biomarkers for diagnosis, prognosis, and disease monitoring. To this concept, the pro-thrombotic and atherogenic potential of platelets and endothelial-derived MPs have gained research interest, especially concerning accelerated atherosclerosis and triggering as well as prognosis of an acute coronary syndrome. MPs, especially those of endothelial origin, have been investigated in different clinical scenarios of heart failure and in association with left ventricular loading conditions. Finally, most cardiovascular risk factors present unique features in the circulating MPs population, highlighting their pathophysiologic link to cardiovascular disease progression. In this review article, we present a synopsis of the biogenesis and characteristics of microparticles, as well as the most recent data concerning their implication in cardiovascular settings.


Assuntos
Aterosclerose , Doenças Cardiovasculares , Micropartículas Derivadas de Células , Aterosclerose/metabolismo , Biomarcadores/metabolismo , Plaquetas/metabolismo , Doenças Cardiovasculares/metabolismo , Micropartículas Derivadas de Células/metabolismo , Humanos
15.
Int J Mol Sci ; 23(15)2022 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-35955743

RESUMO

Glycoprotein (GP) VI is the major platelet collagen receptor and a promising anti-thrombotic target. This was first demonstrated in mice using the rat monoclonal antibody JAQ1, which completely blocks the Collagen-Related Peptide (CRP)-binding site on mouse GPVI and efficiently inhibits mouse platelet adhesion, activation and aggregation on collagen. Here, we show for the first time that JAQ1 cross-reacts with human GPVI (huGPVI), but not with GPVI in other tested species, including rat, rabbit, guinea pig, swine, and dog. We further demonstrate that JAQ1 differently modulates mouse and human GPVI function. Similar to its effects on mouse GPVI (mGPVI), JAQ1 inhibits CRP-induced activation in human platelets, whereas, in stark contrast to mouse GPVI, it does not inhibit the adhesion, activation or aggregate formation of human platelets on collagen, but causes instead an increased response. This effect was also seen with platelets from newly generated human GPVI knockin mice (hGP6tg/tg). These results indicate that the binding of JAQ1 to a structurally conserved epitope in GPVI differently affects its function in human and mouse platelets.


Assuntos
Adesividade Plaquetária , Glicoproteínas da Membrana de Plaquetas , Animais , Plaquetas/metabolismo , Colágeno/metabolismo , Cães , Epitopos/metabolismo , Cobaias , Humanos , Camundongos , Ativação Plaquetária , Agregação Plaquetária , Glicoproteínas da Membrana de Plaquetas/metabolismo , Coelhos , Ratos
16.
Int J Mol Sci ; 23(15)2022 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-35955827

RESUMO

Glycoprotein (GP)VI and integrin αIIbß3 are key signaling receptors in collagen-dependent platelet aggregation and in arterial thrombus formation under shear. The multiple downstream signaling pathways are still poorly understood. Here, we focused on disclosing the integrin-dependent roles of focal adhesion kinase (protein tyrosine kinase 2, PTK2), the shear-dependent collagen receptor GPR56 (ADGRG1 gene), and calcium and integrin-binding protein 1 (CIB1). We designed and synthetized peptides that interfered with integrin αIIb binding (pCIB and pCIBm) or mimicked the activation of GPR56 (pGRP). The results show that the combination of pGRP with PTK2 inhibition or of pGRP with pCIB > pCIBm in additive ways suppressed collagen- and GPVI-dependent platelet activation, thrombus buildup, and contraction. Microscopic thrombus formation was assessed by eight parameters (with script descriptions enclosed). The suppressive rather than activating effects of pGRP were confined to blood flow at a high shear rate. Blockage of PTK2 or interference of CIB1 no more than slightly affected thrombus formation at a low shear rate. Peptides did not influence GPVI-induced aggregation and Ca2+ signaling in the absence of shear. Together, these data reveal a shear-dependent signaling axis of PTK2, integrin αIIbß3, and CIB1 in collagen- and GPVI-dependent thrombus formation, which is modulated by GPR56 and exclusively at high shear. This work thereby supports the role of PTK2 in integrin αIIbß3 activation and signaling.


Assuntos
Complexo Glicoproteico GPIIb-IIIa de Plaquetas , Trombose , Plaquetas/metabolismo , Colágeno/metabolismo , Quinase 1 de Adesão Focal/metabolismo , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Humanos , Peptídeos/metabolismo , Peptídeos/farmacologia , Ativação Plaquetária , Adesividade Plaquetária , Agregação Plaquetária , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Glicoproteínas da Membrana de Plaquetas/metabolismo , Trombose/metabolismo
17.
Int J Mol Sci ; 23(15)2022 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-35955928

RESUMO

Serotonin (5-hydroxytriptamine or 5-HT) is known to be a weak platelet agonist, and is involved in thrombus formation. While 5-HT cannot induce platelet aggregation on its own, when secreted from the alpha granules, it binds to its G-protein Coupled Receptor (GPCR; i.e., 5HT2AR), thereby acting to amplify platelet functional responses (e.g., aggregation). Thus, 5HT2AR-mediated responses are more involved in the secondary amplification of platelet aggregation in the growing thrombus. Therefore, even though 5-HT can be seen as a weak inducer of platelet activation, it is an important amplifier of aggregation triggered by agonists such as ADP, collagen, and epinephrine, thereby enhancing thrombogenesis. The 5HT2AR/5HT2A signaling pathway is of clinical interest to the scientific and medical communities as it has been implicated in the genesis of several forms of cardiovascular disorders. However, efforts to develop antagonists for 5HT2AR as therapeutic agents in cardiovascular diseases have thus far failed due to these reagents having deleterious side-effects, and/or to lack of selectivity, amongst other reasons. In light of research efforts that identified that the 5HT2AR ligand binding domain resides in the second extracellular loop (EL2; amino acids P209-N233), we developed an antibody, i.e., referred to as 5HT2ARAb, against the EL2 region, and characterized its pharmacological activity in the context of platelets. Thus, we utilized platelets from healthy human donors, as well as C57BL/6J mice (10-12 weeks old) to analyze the inhibitory effects of the 5HT2ARAb on platelet activation in vitro, ex vivo, and on thrombogenesis in vivo as well as on 5HT2AR ligand binding. Our results indicate that the 5HT2ARAb inhibits 5-HT-enhanced platelet activation in vitro and ex vivo, but has no apparent effects on that which is agonist-induced. The 5HT2ARAb was also found to prolong the thrombus occlusion time, and it did so without modulating the tail bleeding time, in mice unlike the P2Y12 antagonist clopidogrel and the 5HT2AR antagonist ketanserin. Moreover, it was found that the 5HT2ARAb does so by directly antagonizing the platelet 5HT2AR. Our findings document that the custom-made 5HT2ARAb exhibits platelet function blocking activity and protects against thrombogenesis without impairing normal hemostasis.


Assuntos
Serotonina , Trombose , Animais , Anticorpos/metabolismo , Plaquetas/metabolismo , Hemostasia , Humanos , Ligantes , Camundongos , Camundongos Endogâmicos C57BL , Agregação Plaquetária , Inibidores da Agregação Plaquetária/uso terapêutico , Receptor 5-HT2A de Serotonina/metabolismo , Serotonina/metabolismo , Serotonina/farmacologia , Trombose/tratamento farmacológico , Trombose/metabolismo
18.
Biomed Res Int ; 2022: 4893859, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35937403

RESUMO

Evodia rutaecarpa has multiple pharmacological effects and is widely used in the prevention and treatment of migraine, diabetes, cardiovascular disease, cancer, and other chronic diseases; however, the pharmacological effects of its active compound evodiamine (Evo) have not been thoroughly investigated. The purpose of this study was to investigate the effects of Evo on antiplatelet activation and thrombosis. We discovered that Evo effectively inhibited collagen-induced platelet activation but had no effect on platelet aggregation caused by activators such as thrombin, ADP, and U46619. Second, we found that Evo effectively inhibited the release of platelet granules induced by collagen. Finally, evodiamine inhibits the transduction of the SFKs/Syk/Akt/PLCγ2 activation pathway in platelets. According to in vivo studies, Evo significantly prolonged the mesenteric thromboembolism induced by ferric chloride and had no discernible effect on the coagulation function of mice. In conclusion, the antiplatelet and thrombotic effects of Evo discovered in this study provide an experimental basis for the investigation of the pharmacological mechanisms of Evo and the development of antiplatelet drugs.


Assuntos
Ativação Plaquetária , Trombose , Animais , Plaquetas/metabolismo , Colágeno/metabolismo , Camundongos , Agregação Plaquetária , Inibidores da Agregação Plaquetária/farmacologia , Inibidores da Agregação Plaquetária/uso terapêutico , Quinazolinas , Trombose/etiologia
19.
Thromb Res ; 217: 96-103, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35926348

RESUMO

Eptifibatide is an αIIbß3 inhibitor that is currently used in the clinic. More than 10 scientific communications indicate that eptifibatide has a Lys-Gly-Asp or Arg-Gly-Asp sequence, while it actually has a hArg-Gly-Asp sequence. We aimed to unravel the importance of the homoarginine residue in eptifibatide in platelet activation and aggregation. Arg- and Lys-eptifibatide were synthesized by solid-phase peptide synthesis and measured in light transmission aggregometry, flow cytometry and whole blood thrombus formation under flow. Interactions of eptifibatide and its variants with αIIbß3 integrin were studied using molecular dynamics simulations. Eptifibatide showed inhibition of collagen- and ADP-induced platelet aggregation, while Arg- and Lys-eptifibatide did not. Multiparameter assessment of thrombus formation showed suppressed platelet aggregate and fibrin formation upon eptifibatide treatment, in contrast to the other variants. Molecular dynamics simulations revealed that the hArg residue in eptifibatide is crucial to its activity, since the substitution of the hArg to Arg or Lys resulted in the inability to form double H-bonds with Asp224 in the αIIb chain of the αIIbß3 receptor. The hArg is pivotal for the interaction of eptifibatide for the αIIbß3 receptor and efficient inhibition of platelet aggregation.


Assuntos
Inibidores da Agregação Plaquetária , Trombose , Plaquetas/metabolismo , Eptifibatida/farmacologia , Homoarginina/metabolismo , Homoarginina/farmacologia , Humanos , Peptídeos/metabolismo , Peptídeos/farmacologia , Agregação Plaquetária , Inibidores da Agregação Plaquetária/farmacologia , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Trombose/tratamento farmacológico , Trombose/metabolismo
20.
Transfusion ; 62(9): 1839-1849, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35924726

RESUMO

BACKGROUND: Human platelet lysate (HPL) has been proposed as a safe and efficient xeno-free alternative to fetal bovine serum (FBS) for large-scale culturing of cell-based medicinal products. However, the use of blood derivatives poses a potential risk of pathogen transmission. To mitigate this risk, different pathogen reduction treatment (PRT) practices can be applied on starting materials or on final products, but these methods might modify the final composition and the quality of the products. STUDY DESIGN AND METHODS: We evaluated the impact of applying a PRT based on riboflavin and ultraviolet irradiation on the raw materials used to manufacture an improved Good Manufacturing Practices (GMP)-grade HPL product in a public blood center. Growth promotion and the levels of growth factors and proteins were compared between an inactivated product (HPL4-i) and a non-inactivated product (HPL4). Stability studies were performed at 4°C, -20°C, and -80°C. RESULTS: The application of a PRT on the starting materials significantly altered the protein composition of HPL4-i as compared with HPL4. Despite this, the growth promoting rates were unaffected when compared with FBS used as a control. While all products were stable at -20°C and -80°C for 24 months, a significant decrease in the activity of HPL4-i was observed when stored at 4°C. CONCLUSION: Our results show that the application of a PRT based on riboflavin and ultraviolet light on starting materials used in the manufacture of HPL modifies the final composition of the product, yet its cell growth promoting activity is maintained at levels similar to those of non-inactivated products.


Assuntos
Plaquetas , Trombopoese , Plaquetas/metabolismo , Transfusão de Sangue , Proliferação de Células , Humanos , Riboflavina/farmacologia
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