86 results on '"Stefania Momi"'
Search Results
2. A nitric oxide-donor pravastatin hybrid drug exerts antiplatelet and antiatherogenic activity in mice
- Author
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Stefania Momi, Giuseppe Guglielmini, Giulia Ciarroca Taranta, Elisa Giglio, Angela Monopoli, and Paolo Gresele
- Subjects
NCX 6550 ,Intimal hyperplasia ,Thrombosis ,Platelets ,Nitric oxide ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Aim of the present study was to compare the lipid-lowering, antithrombotic and antiatherogenic properties of NCX-6550, nitropravastatin, a nitric-oxide donating derivative of pravastatin, with those of pravastatin in hypercholesterolemic mice. LDL receptor-deficient mice (LDLR–/–) on a normal diet (ND) showed enhanced cholesterol levels as compared to wild type (WT) mice (6.8±1.2 mmol/L and 2.8±0.82 mmol/L, respectively). High fat diet (HFD) induced a large enhancement of cholesterolemia in LDLR–/– mice (23.7±5.7 mmol/L, p
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- 2022
- Full Text
- View/download PDF
3. Proline-rich tyrosine kinase Pyk2 regulates deep vein thrombosis
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Stefania Momi, Jessica Canino, Mauro Vismara, Luca Galgano, Emanuela Falcinelli, Giuseppe Guglielmini, Giulia Ciarrocca Taranta, Gianni Francesco Guidetti, Paolo Gresele, Mauro Torti, and Ilaria Canobbio
- Subjects
Diseases of the blood and blood-forming organs ,RC633-647.5 - Abstract
Deep vein thrombosis results from the cooperative action of leukocytes, platelets, and endothelial cells. The proline-rich tyrosine kinase Pyk2 regulates platelet activation and supports arterial thrombosis. In this study, we combined pharmacological and genetic approaches to unravel the role of Pyk2 in venous thrombosis. We found that mice lacking Pyk2 almost completely failed to develop deep venous thrombi upon partial ligation of the inferior vena cava. Pyk2-deficient platelets displayed impaired exposure of phosphatidylserine and tissue factor expression by endothelial cells and monocytes was completely prevented by inhibition of Pyk2. In human umbilical vein endothelial cells (HUVEC), inhibition of Pyk2 hampered IL-1b-induced expression of VCAM and P-selectin, and von Willebrand factor release. Pyk2-deficient platelets showed defective adhesion on von Willebrand factor and reduced ability to bind activated HUVEC under flow. Moreover, inhibition of Pyk2 in HUVEC strongly reduced platelet adhesion. Similarly, Pyk2-deficient neutrophils were unable to efficiently roll and adhere to immobilized endothelial cells under venous flow conditions. Moreover, platelets and neutrophils from Pyk2- knockout mice showed defective ability to form heterogeneous aggregates upon stimulation, while platelet monocyte interaction occurred normally. Consequently, platelet neutrophil aggregates, abundant in blood of wild-type mice upon inferior vena cava ligation, were virtually undetectable in Pyk2-knockout mice. Finally, we found that expression of Pyk2 was required for NETosis induced by activated platelets. Altogether our results demonstrate a critical role of Pyk2 in the regulation of the coordinated thromboinflammatory responses of endothelial cells, leukocytes and platelets leading to venous thrombosis. Pyk2 may represent a novel promising target in the treatment of deep vein thrombosis.
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- 2022
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- View/download PDF
4. Platelet dysfunction in platelet-type von Willebrand disease due to the constitutive triggering of the Lyn-PECAM1 inhibitory pathway
- Author
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Loredana Bury, Emanuela Falcinelli, Anna Maria Mezzasoma, Giuseppe Guglielmini, Stefania Momi, and Paolo Gresele
- Subjects
Diseases of the blood and blood-forming organs ,RC633-647.5 - Abstract
Platelet-type von Willebrand disease (PT-VWD) is an inherited platelet disorder. It is characterized by macrothrombocytopenia and mucocutaneous bleeding, of variable severity, due to gain-of-function variants of GP1BA conferring to glycoprotein Ibα (GPIbα) enhanced affinity for von Willebrand factor (VWF). The bleeding tendency is conventionally attributed to thrombocytopenia and large VWF-multimer depletion. However, while some indications suggest that platelet dysfunction may contribute to the bleeding phenotype, no information on its characteristics and causes are available. The aim of the present study was to characterize platelet dysfunction in PT-VWD and shed light on its mechanism. Platelets from a PT-VWD patient carrying the p.M239V variant, and from PT-VWD mice carrying the p.G233V variant, showed a remarkable platelet function defect, with impaired aggregation, defective granule secretion and reduced adhesion under static and flow conditions. VWFbinding to GPIbα is known to trigger intracellular signaling involving Src-family kinases (SFK). We found that constitutive phosphorylation of the platelet SFK Lyn induces a negative-feedback loop downregulating platelet activation through phosphorylation of PECAM1 on Tyr686 and that this is triggered by the constitutive binding of VWF to GPIbα. These data show, for the first time, that the abnormal triggering of inhibitory signals mediated by Lyn and PECAM1 may lead to platelet dysfunction. In conclusion, our study unravels the mechanism of platelet dysfunction in PT-VWD caused by deranged inhibitory signaling. This is triggered by the constitutive binding of VWF to GPIbα which may significantly contribute to the bleeding phenotype of these patients.
- Published
- 2021
- Full Text
- View/download PDF
5. Interactions of adenoviruses with platelets and coagulation and the vaccine-induced immune thrombotic thrombocytopenia syndrome
- Author
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Paolo Gresele, Stefania Momi, Rossella Marcucci, Francesco Ramundo, Valerio De Stefano, and Armando Tripodi
- Subjects
Diseases of the blood and blood-forming organs ,RC633-647.5 - Abstract
The COVID-19 pandemic has had a heavy impact on global health and economy and vaccination remains the primary way of controlling the infection. During the ongoing vaccination campaign some unexpected thrombotic events have emerged in subjects who had recently received the AstraZeneca (Vaxzevria) vaccine or the Johnson and Johnson (Janssen) vaccine, two adenovirus vector-based vaccines. Epidemiological studies confirm that the observed/expected ratio of these unusual thromboses is abnormally increased, especially in women in fertile age. The characteristics of this complication, with venous thromboses at unusual sites, most frequently in the cerebral vein sinuses but also in splanchnic vessels, often with multiple associated thromboses, thrombocytopenia, and sometimes disseminated intravascular coagulation, are unique and the time course and tumultuous evolution are suggestive of an acute immunological reaction. Indeed, plateletactivating anti-PF4 antibodies have been detected in a large proportion of the affected patients. Several data suggest that adenoviruses may interact with platelets, the endothelium and the blood coagulation system. Here we review interactions between adenoviral vectors and the hemostatic system that are of possible relevance in vaccine-associated thrombotic thrombocytopenia syndrome. We systematically analyze the clinical data on the reported thrombotic complications of adenovirus-based therapeutics and discuss all the current hypotheses on the mechanisms triggering this novel syndrome. Although, considering current evidence, the benefit of vaccination clearly outweighs the potential risks, it is of paramount importance to fully unravel the mechanisms leading to vaccineassociated thrombotic thrombocytopenia syndrome and to identify prognostic factors through further research.
- Published
- 2021
- Full Text
- View/download PDF
6. Mechanisms of thrombocytopenia in platelet-type von Willebrand disease
- Author
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Loredana Bury, Alessandro Malara, Stefania Momi, Eleonora Petito, Alessandra Balduini, and Paolo Gresele
- Subjects
Diseases of the blood and blood-forming organs ,RC633-647.5 - Abstract
Platelet-type von Willebrand disease is an inherited platelet disorder characterized by thrombocytopenia with large platelets caused by gain-of-function variants in GP1BA leading to enhanced GPIbα-von Willebrand factor (vWF) interaction. GPIbα and vWF play a role in megakaryocytopoiesis, thus we aimed to investigate megakaryocyte differentiation and proplatelet-formation in platelet-type von Willebrand disease using megakaryocytes from a patient carrying the Met239Val variant and from mice carrying the Gly233Val variant. Platelet-type von Willebrand disease megakaryocytes bound vWF at an early differentiation stage and generated proplatelets with a decreased number of enlarged tips compared to control megakaryocytes. Moreover, they formed proplatelets upon contact with collagen, differently from normal megakaryocytes. Similarly, collagen triggered megakaryocytes showed defective activation of the RhoA-MLC2 axis, which prevents proplatelet formation, and increased phosphorylation of Lyn, which acts as a negative regulator of GPVI signaling, thus preventing ectopic proplatelet-formation on collagen. Consistently, human and murine bone marrow contained an increased number of extravascular platelets compared to controls. In addition, platelet survival of mutant mice was shortened compared to control mice, and the administration of desmopressin, raising circulating vWF, caused a marked drop in platelet count. Taken together, these results show for the first time that thrombocytopenia in platelet-type von Willebrand disease is due to the combination of different pathogenic mechanisms, i.e. the formation of a reduced number of platelets by megakaryocytes, the ectopic release of platelets in the bone marrow, and the increased clearance of platelet/vWF complexes.
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- 2019
- Full Text
- View/download PDF
7. Alteration of liver enzymes is a feature of the MYH9-related disease syndrome.
- Author
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Alessandro Pecci, Ginevra Biino, Tiziana Fierro, Valeria Bozzi, Annamaria Mezzasoma, Patrizia Noris, Ugo Ramenghi, Giuseppe Loffredo, Fabrizio Fabris, Stefania Momi, Umberto Magrini, Mario Pirastu, Anna Savoia, Carlo Balduini, Paolo Gresele, and Italian Registry for MYH9-releated diseases
- Subjects
Medicine ,Science - Abstract
BACKGROUND: MYH9-related disease (MYH9-RD) is a rare autosomal dominant genetic syndrome characterized by congenital thrombocytopenia associated with the risk of developing progressive nephropathy, sensorineural deafness, and presenile cataract. During the collection of a large case-series of patients with MYH9-RD we noticed several cases with unexplained elevation of liver enzymes. Our aim was to evaluate if the alteration of liver tests is a feature of the MYH9-RD and to define its clinical significance. METHODS AND FINDINGS: Data concerning liver tests, prospectively recorded in the Italian Registry for MYH9-RD, were collected and compared with those of three control populations: patients with autoimmune thrombocytopenia, patients with inherited thrombocytopenias other than MYH9-RD, and the participants to a large epidemiologic survey in an Italian geographic isolate. Thirty-eight of 75 evaluable MYH9-RD patients (50.7%) showed an elevation of ALT and/or AST, and 17 of 63 (27.0%) an increase of GGT. The increases ranged from 1.9 ± 0.7 to 2.7 ± 1.6 fold the upper normal limit. The prevalence of liver test alterations was significantly higher in MYH9-RD patients than in each of the control populations, with odds ratios ranging from 8.2 (95% CIs 2.2-44.8) to 24.7 (14.8-40.8). Clinical follow-up and more detailed liver studies of a subset of patients, including ultrasound liver scan, liver elastography and liver biopsy in one case, did not show any significant structural damage or evolution towards liver insufficiency. CONCLUSIONS: Elevation of liver enzymes is a frequent and previously unrecognized feature of the MYH9-RD syndrome; however, this defect does not appear to have poor prognostic value.
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- 2012
- Full Text
- View/download PDF
8. Novel approaches to antiplatelet therapy
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Paolo Gresele and Stefania Momi
- Subjects
Pharmacology ,Blood Platelets ,Fibrinolytic Agents ,Animals ,Humans ,Thrombosis ,Platelet Activation ,Biochemistry ,Platelet Aggregation Inhibitors - Abstract
Platelets are the main effectors of the thrombotic events occurring at a ruptured atherosclerotic plaque and therefore antiplatelet agents are the mainstay of antithrombotic treatment for the prevention of myocardial infarction, atherotrombotic ischemic stroke and critical limb ischemia due to the thrombotic occlusion of the peripheral arteries. Despite great progress in antiplatelet agents over the last two decades, a number of important unmet medical needs still remain, like insufficient efficacy and a high incidence of hemorrhagic complications. Advances in the knowledge of the molecular mechanisms regulating platelet participation in hemostasis and in thrombosis and progress in pharmaceutical design have allowed to identify new drugs for established antiplatelet targets and novel targets for the development of new agents. Among the latter, several innovative approaches have already proceeded to clinical testing, like GPVI antagonism, PAR4 antagonism, PI3K inhibition, and some preliminary results seem promising. Here we review the pharmacologic approaches to platelet inhibition currently available and in development for their effects on platelet activation in vitro and on thrombosis in animal models and in humans. An ideal antithrombotic agent should selectively target events crucial for pathological thrombus formation without affecting hemostasis, an objective so far not achieved: if one or more of the novel agents in development will reach this goal this will represent a great step forward in the prevention of ischemic cardiovascular events.
- Published
- 2022
9. Platelets and Matrix Metalloproteinases: A Bidirectional Interaction with Multiple Pathophysiologic Implications
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Manuela Sebastiano, Eleonora Petito, Stefania Momi, Paolo Gresele, and Emanuela Falcinelli
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Blood Platelets ,0301 basic medicine ,business.industry ,Inflammation ,Hematology ,Disease ,030204 cardiovascular system & hematology ,Matrix metalloproteinase ,Atherosclerosis ,medicine.disease ,Matrix Metalloproteinases ,Review article ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Immune system ,Hemostasis ,Cancer research ,Humans ,Medicine ,Platelet ,medicine.symptom ,Thrombus ,business - Abstract
Platelets contain and release several matrix metalloproteinases (MMPs), a highly conserved protein family with multiple functions in organism defense and repair. Platelet-released MMPs as well as MMPs generated by other cells within the cardiovascular system modulate platelet function in health and disease. In particular, a normal hemostatic platelet response to vessel wall injury may be transformed into pathological thrombus formation by platelet-released and/or by locally generated MMPs. However, it is becoming increasingly clear that platelets play a role not only in hemostasis but also in immune response, inflammation and allergy, atherosclerosis, and cancer development, and MMPs seem to contribute importantly to this role. A deeper understanding of these mechanisms may open the way to novel therapeutic approaches to the inhibition of their pathogenic effects and lead to significant advances in the treatment of cardiovascular, inflammatory, and neoplastic disorders.
- Published
- 2021
10. Pleiotropic effects of PCSK9-inhibition on hemostasis: Anti-PCSK9 reduce FVIII levels by enhancing LRP1 expression
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Francesco Paciullo, Eleonora Petito, Emanuela Falcinelli, Paolo Gresele, and Stefania Momi
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Hemostasis ,Factor VIII ,Receptors, LDL ,Anticholesteremic Agents ,PCSK9 Inhibitors ,Humans ,Hematology ,Proprotein Convertase 9 ,Low Density Lipoprotein Receptor-Related Protein-1 - Published
- 2022
11. Interactions of adenoviruses with platelets and coagulation and the vaccine-induced immune thrombotic thrombocytopenia syndrome
- Author
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Armando Tripodi, Stefania Momi, Rossella Marcucci, Paolo Gresele, Valerio De Stefano, and Francesco Ramundo
- Subjects
Blood Platelets ,COVID-19 Vaccines ,Review Article ,Autoimmune thrombocytopenia ,Viral vector ,Adenoviridae ,medicine ,Humans ,Platelet ,Blood Coagulation ,Pandemics ,Disseminated intravascular coagulation ,Vaccines ,business.industry ,SARS-CoV-2 ,COVID-19 ,Thrombosis ,Hematology ,medicine.disease ,Thrombocytopenia ,Vaccination ,Coagulation ,Immunology ,Female ,Complication ,business - Abstract
The COVID-19 pandemic has had a heavy impact on global health and economy and vaccination remains the primary way of controlling the infection. During the ongoing vaccination campaign some unexpected thrombotic events have emerged in subjects who had recently received the AstraZeneca (Vaxzevria) vaccine or the Johnson and Johnson (Janssen) vaccine, two adenovirus vector-based vaccines. Epidemiological studies confirm that the observed/expected ratio of these unusual thromboses is abnormally increased, especially in women in fertile age. The characteristics of this complication, with venous thromboses at unusual sites, most frequently in the cerebral vein sinuses but also in splanchnic vessels, often with multiple associated thromboses, thrombocytopenia, and sometimes disseminated intravascular coagulation, are unique and the time course and tumultuous evolution are suggestive of an acute immunological reaction. Indeed, plateletactivating anti-PF4 antibodies have been detected in a large proportion of the affected patients. Several data suggest that adenoviruses may interact with platelets, the endothelium and the blood coagulation system. Here we review interactions between adenoviral vectors and the hemostatic system that are of possible relevance in vaccine-associated thrombotic thrombocytopenia syndrome. We systematically analyze the clinical data on the reported thrombotic complications of adenovirus-based therapeutics and discuss all the current hypotheses on the mechanisms triggering this novel syndrome. Although, considering current evidence, the benefit of vaccination clearly outweighs the potential risks, it is of paramount importance to fully unravel the mechanisms leading to vaccineassociated thrombotic thrombocytopenia syndrome and to identify prognostic factors through further research.
- Published
- 2021
12. Nitric oxide-enhancing or -releasing agents as antithrombotic drugs
- Author
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Giuseppe Guglielmini, Paolo Gresele, and Stefania Momi
- Subjects
Blood Platelets ,0301 basic medicine ,Platelet Aggregation ,Vasodilation ,Pharmacology ,Nitric Oxide ,Biochemistry ,Nitric oxide ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Mediator ,Fibrinolytic Agents ,In vivo ,Antithrombotic ,Animals ,Humans ,Medicine ,Nitric Oxide Donors ,Platelet ,Platelet activation ,business.industry ,Thrombosis ,Bioavailability ,030104 developmental biology ,chemistry ,030220 oncology & carcinogenesis ,business ,Platelet Aggregation Inhibitors - Abstract
Nitric oxide (NO) is a powerful biological mediator provided with a number of activities of relevance for the prevention of thrombosis, like vasodilation, inhibition of platelet adhesion and aggregation, prevention of smooth muscle cell proliferation. Several cells in the circulation release NO, like endothelial cells which are the largest source, red blood cells, platelets and white blood cells, and conditions associated with an impaired production or bioavailability of NO predispose to arterial and venous thrombosis. It seems thus logical to use NO as an antithrombotic agent. However, given the extremely short half-life, limited water solubility and radical nature of this mediator, several chemical strategies to generate drugs releasing NO and/or favouring its endogenous production/bioavailability have been developed. Here we review the pharmacologic approaches to enhance endogenous NO or to induce NO-release developed over the last decades for their effects on platelet activation in vitro and in vivo and on thrombosis, in animal models and in humans. One limitation to the development of NO-releasing agents as antithrombotic drugs is represented by their concomitant vasodilatory action which, by inducing hypotension, limits their applicability. Further pharmacologic and clinical research of novel NO-enhancing and/or -releasing molecules is highly warranted in order to fully exploit the great antithrombotic potential of NO.
- Published
- 2019
13. Platelet dysfunction in platelet-type von Willebrand disease due to the constitutive triggering of the Lyn-PECAM1 inhibitory pathway
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Emanuela Falcinelli, Stefania Momi, Paolo Gresele, Loredana Bury, Anna Maria Mezzasoma, and Giuseppe Guglielmini
- Subjects
Blood Platelets ,congenital, hereditary, and neonatal diseases and abnormalities ,Hemorrhage ,Mice ,Von Willebrand factor ,LYN ,hemic and lymphatic diseases ,von Willebrand Factor ,Platelet-Type von Willebrand Disease ,Von Willebrand disease ,medicine ,Animals ,Platelet ,Platelet activation ,biology ,Chemistry ,Hematology ,medicine.disease ,Thrombocytopenia ,Platelet Endothelial Cell Adhesion Molecule-1 ,GP1BA ,von Willebrand Diseases ,Platelet Glycoprotein GPIb-IX Complex ,biology.protein ,Cancer research ,Phosphorylation - Abstract
Platelet-type von Willebrand disease (PT-VWD) is an inherited platelet disorder. It is characterized by macrothrombocytopenia and mucocutaneous bleeding, of variable severity, due to gain-of-function variants of GP1BA conferring to glycoprotein Ibα (GPIbα) enhanced affinity for von Willebrand factor (VWF). The bleeding tendency is conventionally attributed to thrombocytopenia and large VWF-multimer depletion. However, while some indications suggest that platelet dysfunction may contribute to the bleeding phenotype, no information on its characteristics and causes are available. The aim of the present study was to characterize platelet dysfunction in PT-VWD and shed light on its mechanism. Platelets from a PT-VWD patient carrying the p.M239V variant, and from PT-VWD mice carrying the p.G233V variant, showed a remarkable platelet function defect, with impaired aggregation, defective granule secretion and reduced adhesion under static and flow conditions. VWFbinding to GPIbα is known to trigger intracellular signaling involving Src-family kinases (SFK). We found that constitutive phosphorylation of the platelet SFK Lyn induces a negative-feedback loop downregulating platelet activation through phosphorylation of PECAM1 on Tyr686 and that this is triggered by the constitutive binding of VWF to GPIbα. These data show, for the first time, that the abnormal triggering of inhibitory signals mediated by Lyn and PECAM1 may lead to platelet dysfunction. In conclusion, our study unravels the mechanism of platelet dysfunction in PT-VWD caused by deranged inhibitory signaling. This is triggered by the constitutive binding of VWF to GPIbα which may significantly contribute to the bleeding phenotype of these patients.
- Published
- 2021
14. Matrix metalloproteinase-2 on activated platelets triggers endothelial PAR-1 initiating atherosclerosis
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Paolo Gresele, Stefania Momi, Emanuela Falcinelli, Eleonora Petito, Alice Ossoli, and Giulia Ciarrocca Taranta
- Subjects
Platelets ,Blood Platelets ,PAR-1 ,HIV Infections ,Matrix metalloproteinase ,Mice ,medicine.artery ,medicine ,Animals ,Humans ,Platelet ,Platelet activation ,Mice, Knockout ,Aorta ,MMP-2 ,Cell adhesion molecule ,business.industry ,Monocyte ,Endothelial Cells ,Atherosclerosis ,In vitro ,Mice, Inbred C57BL ,medicine.anatomical_structure ,LDL receptor ,Cancer research ,Matrix Metalloproteinase 2 ,Cardiology and Cardiovascular Medicine ,business - Abstract
Aims Platelets participate in atherogenesis with mechanisms not yet fully clarified. Vascular wall MMP-2 is involved in the arterial remodelling accompanying atherosclerosis. Platelets contain and release MMP-2 but no informations are available on its role in atherosclerotic lesion formation. Methods and results We generated double knockout mice lacking the LDL receptor and MMP-2 only in circulating blood cells showing that they develop significantly lesser femoral intima thickening after photochemical-induced arterial damage and atherosclerotic lesions in the aorta, measured by the en face method, after 4 months of atherogenic diet. Moreover, repeated transfusions of autologous-activated platelets in LDLR−/− mice on atherogenic diet significantly enhanced the extension of aortic atherosclerotic lesions while transfusion of activated platelets from MMP-2−/− mice did not. In vitro coincubation studies showed that platelet-derived MMP-2 plays a pivotal role in the development and progression of atherosclerosis through a complex cross-talk between activated platelets, monocyte/macrophages, and endothelial cells. Translational studies in patients with CAD and chronic HIV infection showed that platelet surface expression of MMP-2 highly significantly correlated with the degree of carotid artery stenosis. Conclusion We show a previously unknown mechanism of the pathway through which platelets expressing MMP-2 trigger the initial phases of atherosclerosis and provide a mechanism showing that they activate endothelial PAR-1 triggering endothelial p38MAPK signalling and the expression of adhesion molecules. The development of drugs blocking selectively platelet MMP-2 or its expression may represent a new approach to the prevention of atherosclerosis.
- Published
- 2020
15. PCSK9 in Haemostasis and Thrombosis: Possible Pleiotropic Effects of PCSK9 Inhibitors in Cardiovascular Prevention
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Paolo Gresele, Francesco Paciullo, and Stefania Momi
- Subjects
FVIII ,0301 basic medicine ,Blood Platelets ,dyslipidaemia ,Serine Proteinase Inhibitors ,Time Factors ,030204 cardiovascular system & hematology ,Pharmacology ,03 medical and health sciences ,0302 clinical medicine ,P2Y12 ,Fibrinolytic Agents ,Risk Factors ,atherothrombosis ,Medicine ,Animals ,Humans ,Platelet ,Platelet activation ,Dyslipidemias ,Hemostasis ,business.industry ,PCSK9 ,Anticholesteremic Agents ,PCSK9 Inhibitors ,Hematology ,medicine.disease ,Platelet Activation ,Thrombosis ,Lipids ,LOX-1 ,030104 developmental biology ,Treatment Outcome ,Coagulation ,Cardiovascular Diseases ,LDL receptor ,CD36 ,Proprotein Convertase 9 ,business ,Biomarkers ,Platelet Aggregation Inhibitors ,Lipoprotein - Abstract
Since increased cholesterol levels are crucial in determining the development of atheroma, their reduction represents a mainstay in primary and secondary cardiovascular prevention. The most recent spectacular advancement in cholesterol-lowering therapy is represented by proprotein convertase subtilisin/kexin type-9 (PCSK9) inhibitors. Although their benefit over currently available treatments has been ascribed primarily to their strong low-density lipoprotein (LDL)-cholesterol reducing action, several clues suggest that PCSK9 inhibitors may also influence platelet function and blood coagulation. PCSK9 knockout mice develop less venous and arterial thrombosis and show reduced in vivo platelet activation upon arterial injury. In patients with acute coronary syndromes (ACSs) treated with P2Y12 inhibitors, a direct association between PCSK9 serum levels and residual platelet reactivity was found. A direct correlation between urinary excretion of 11-dehydro-thromboxane-B2, a marker of in vivo platelet activation, and circulating PCSK9 levels was reported in patients with atrial fibrillation. Moreover, recombinant human PCSK9 added in vitro to human platelets potentiated activation induced by weak agonists. Finally, blood clotting factor VIII (FVIII), which is associated with stroke and ACS risk, is cleared from the circulation by members of the LDL receptor (LDLR) family. Given that PCSK9 degrades LDLR, it is conceivable that PCSK9 inhibitors by enhancing the expression of LDLR may slightly decrease circulating FVIII, in this way contributing to the prevention of cardiovascular events. This review aims to discuss the possible and hypothetical interactions between PCSK9 and the haemostatic system and to examine the possible pleiotropic effects of PCSK9 inhibitors in cardiovascular prevention.
- Published
- 2019
16. Mechanisms of thrombocytopenia in platelet-type von Willebrand disease
- Author
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Eleonora Petito, Alessandra Balduini, Paolo Gresele, Loredana Bury, Alessandro Malara, and Stefania Momi
- Subjects
Blood Platelets ,platelet-type von willebrand disease ,medicine.medical_specialty ,Megakaryocyte differentiation ,Disorders of Platelet Function ,Mice, Transgenic ,Thrombopoiesis ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Cell Movement ,megakaryocytes ,hemic and lymphatic diseases ,Internal medicine ,von Willebrand Factor ,Von Willebrand disease ,medicine ,Platelet-Type von Willebrand Disease ,Animals ,Humans ,Platelet ,Megakaryocytopoiesis ,Chemistry ,Hematopoietic Stem Cell ,Hematology ,medicine.disease ,Thrombocytopenia ,Mice, Inbred C57BL ,von Willebrand Diseases ,GP1BA ,Editorial ,Endocrinology ,Platelet Glycoprotein GPIb-IX Complex ,Case-Control Studies ,Mutation ,GPVI ,030215 immunology - Abstract
Platelet-type von Willebrand disease is an inherited platelet disorder characterized by thrombocytopenia with large platelets caused by gain-of-function variants in GP1BA leading to enhanced GPIbα-von Willebrand factor (vWF) interaction. GPIbα and vWF play a role in megakaryocytopoiesis, thus we aimed to investigate megakaryocyte differentiation and proplatelet-formation in platelet-type von Willebrand disease using megakaryocytes from a patient carrying the Met239Val variant and from mice carrying the Gly233Val variant. Platelet-type von Willebrand disease megakaryocytes bound vWF at an early differentiation stage and generated proplatelets with a decreased number of enlarged tips compared to control megakaryocytes. Moreover, they formed proplatelets upon contact with collagen, differently from normal megakaryocytes. Similarly, collagen triggered megakaryocytes showed defective activation of the RhoA-MLC2 axis, which prevents proplatelet formation, and increased phosphorylation of Lyn, which acts as a negative regulator of GPVI signaling, thus preventing ectopic proplatelet-formation on collagen. Consistently, human and murine bone marrow contained an increased number of extravascular platelets compared to controls. In addition, platelet survival of mutant mice was shortened compared to control mice, and the administration of desmopressin, raising circulating vWF, caused a marked drop in platelet count. Taken together, these results show for the first time that thrombocytopenia in platelet-type von Willebrand disease is due to the combination of different pathogenic mechanisms, i.e. the formation of a reduced number of platelets by megakaryocytes, the ectopic release of platelets in the bone marrow, and the increased clearance of platelet/vWF complexes.
- Published
- 2019
17. Nitric Oxide and its Antithrombotic Action in the Cardiovascular System
- Author
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Gustavo, Reichenbach, Stefania, Momi, and Paolo, Gresele
- Published
- 2005
18. Randomized Trial of Hymovis® versus Synvisc® on Matrix Metalloproteinases in Knee Osteoarthritis
- Author
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Paolo Gresele, Elisa Piselli, Roberto Gerli, Eleonora Petito, Emanuela Falcinelli, G M C La Paglia, Nicola Giordan, Alessia Alunno, Giulia Mirabelli, Stefania Momi, and F. Luccioli
- Subjects
medicine.medical_specialty ,Randomized controlled trial ,law ,business.industry ,Internal medicine ,medicine ,Orthopedics and Sports Medicine ,Osteoarthritis ,Matrix metalloproteinase ,medicine.disease ,business ,law.invention - Published
- 2020
19. A dichotomy in platelet activation: Evidence of different functional platelet responses to inflammatory versus haemostatic stimuli
- Author
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Stefania Momi, Richard T. Amison, Simon C. Pitchford, Clive P. Page, Eleonora Petito, Elisa Piselli, Sajeel A. Shah, and Paolo Gresele
- Subjects
0301 basic medicine ,Platelets ,Blood Platelets ,Platelet Aggregation ,Stimulation ,Inflammation ,030204 cardiovascular system & hematology ,Pharmacology ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Chemotaxis ,Haemostasis ,Leukocytes ,Thrombosis ,Cell Movement ,Humans ,Phosphorylation ,Hemostasis ,Platelet Activation ,Hematology ,medicine ,Platelet ,Platelet activation ,Convulxin ,030104 developmental biology ,Epinephrine ,chemistry ,medicine.symptom ,Histamine ,medicine.drug - Abstract
Introduction Platelets participate in inflammatory disorders through a variety of different functional responses, including chemotaxis, platelet-leukocyte complex formation and facilitation of leukocyte recruitment that are thought to be distinct from platelet aggregation. This may account for why classical anti-platelet drugs have failed to ameliorate inflammatory disorders where platelets are known to participate, suggesting that distinct pathways may control inflammatory and haemostatic functions of platelets. In the present study, we have therefore investigated the effect of different stimuli on several different functions of platelets preferentially involved either in haemostasis or in inflammation. Materials and methods Human platelets were stimulated with either inflammatory (fMLP, histamine, IL-1β, LPS, MDC/CCL22, SDF-1α/CXCL12 and 5-HT) or haemostatic (ADP, collagen, convulxin, epinephrine, TRAP-6 and U46619) stimuli. Aggregation, platelet-leukocyte complex formation, platelet migration and platelet protein phosphorylation were assessed. Results Haemostatic stimuli induced platelet aggregation, whilst inflammatory agonists induced platelet migration. The haemostatic stimuli, with the exception of epinephrine, and some of the inflammatory stimuli induced platelet-leukocyte complex formation, even if to a different extent. Furthermore, inflammatory stimuli induced a shorter lasting profile of platelet protein phosphorylation compared with haemostatic stimuli. Conclusions Stimulation of platelets with inflammatory stimuli triggers the activation of non haemostatic functions different from those induced by haemostatic stimuli, supporting the existence of alternative platelet responses depending on the stimulus (haemostatic or inflammatory). A deeper understanding of the biochemical pathways behind these functional differences may lead to the development of novel therapeutic options targeting the inflammatory actions of platelets, without affecting their critical role in haemostasis.
- Published
- 2018
20. Anti-platelet treatments in cancer: Basic and clinical research
- Author
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Stefania Momi, Paolo Gresele, and Marco Malvestiti
- Subjects
0301 basic medicine ,Drug ,Blood Platelets ,Platelets ,P2Y12 ,media_common.quotation_subject ,Disease ,Metastasis ,03 medical and health sciences ,0302 clinical medicine ,Neoplasms ,Medicine ,Humans ,Platelet ,Platelet-therapy ,media_common ,business.industry ,Cancer ,Hematology ,medicine.disease ,Cyclooxygenase ,030104 developmental biology ,030220 oncology & carcinogenesis ,Phosphodiesterases ,Cancer cell ,Cancer research ,Platelet aggregation inhibitor ,business ,Platelet Aggregation Inhibitors - Abstract
Over the past few decades the central role that platelets play in cancer development and progression, and especially in metastasis, has been elucidated. The molecular mechanisms responsible for initiating and mediating tumor cell-induced platelet aggregation and secretion have been largely unravelled. Considerable mechanistic insight into how platelets contribute to tumor angiogenesis, immunoevasion and cancer cell invasion have been clarified and, consequently, platelets have been identified as potential new drug targets for cancer therapy. This article gives an overview of the platelet-targeted pharmacologic approaches that have been attempted in the prevention of cancer development, progression and metastasis, including the application of antiplatelet drugs currently used for cardiovascular disease and of new and novel strategies.
- Published
- 2018
21. Platelets and airway diseases
- Author
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Stefania Momi, Paolo Gresele, Simon C. Pitchford, and Clive P. Page
- Subjects
0301 basic medicine ,Lung ,Endothelium ,business.industry ,respiratory system ,medicine.disease ,Cystic fibrosis ,Pathophysiology ,respiratory tract diseases ,Microcirculation ,Lung Disorder ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,medicine.anatomical_structure ,030228 respiratory system ,Immunology ,medicine ,Platelet ,Platelet activation ,business - Abstract
The role of platelets as inflammatory cells is now well established. Given the peculiar characteristics of the lung circulation, with a broad capillary bed, platelets are especially involved with the physiology of the lungs and play a key role in a number of inflammatory lung disorders. The platelet precursors, megakaryocytes, are detected in the lung microcirculation; moreover platelets with their endothelium-protective and vascular reparative activities contribute to the lung capillary blood barrier integrity. Given the function of the lungs as first wall against pathogen invasion, platelets participate in immune defence of the normal lung. On the other hand, platelets may turn into effectors of the inflammatory reaction of the lungs to allergens, to infectious agents, to chemical agents and may contribute strongly to the perpetuation of chronic inflammatory reactions, largely by their ability to interact with other inflammatory cells and the endothelium. In this chapter we provide an overview of the role of platelets in several inflammatory lung disorders discussing the pathophysiologic bases of platelet involvement in these conditions and the experimental and clinical evidence for a role of platelets in lung diseases.
- Published
- 2018
22. The migration of platelets and their interaction with other migrating cells
- Author
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Stefania Momi, Paolo Gresele, and Eleonora Petito
- Subjects
0301 basic medicine ,Formyl peptide receptor ,Chemistry ,Chemotaxis ,Lower compartment ,030204 cardiovascular system & hematology ,medicine.disease ,Thrombosis ,In vitro ,Cell biology ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,In vivo ,medicine ,Platelet - Abstract
Platelets, beyond their well-described role in haemostasis and thrombosis, act as inflammatory cells playing an active role in several inflammatory conditions. As observed with other inflammatory cells platelets can migrate in vitro, either randomly or in the direction of a chemotactic agent, and in vivo, into inflammed tissues in response to different stimuli. In this chapter we will summarize the current knowledge about the mechanisms that regulate platelet chemotaxis, the evidence for the ability of platelets to migrate in vitro and in vivo, and the mechanisms by which platelets influence chemotaxis of other cells.
- Published
- 2018
23. Matrix Metalloproteinases and Platelet Function
- Author
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Paolo Gresele, Stefania Momi, Manuela Sebastiano, and Emanuela Falcinelli
- Subjects
0301 basic medicine ,Pathology ,medicine.medical_specialty ,Chemistry ,Arterial aneurysm ,Cancer ,Tumor cells ,030204 cardiovascular system & hematology ,Matrix metalloproteinase ,medicine.disease ,Molecular medicine ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Cancer research ,medicine ,Platelet ,Thrombus ,Function (biology) - Abstract
Platelets contain and release several matrix metalloproteinases (MMPs) and their tissue inhibitors of matrix metalloproteinases (TIMPs), including MMP-1, -2, -3, -9, and -14 and TIMP-1, -2, and -4. Although devoid of a nucleus, platelets also synthesize TIMP-2 upon activation. Platelet-released MMPs/TIMPs, as well as MMPs generated by other cells within the cardiovascular system, modulate platelet function in health and disease. In particular, a normal hemostatic platelet response to vessel wall injury may be transformed into pathologic thrombus formation by the release from platelets and/or by the local generation of some MMPs. Moreover, platelets may localize the production of leukocyte-derived MMPs to sites of vascular damage, contributing to atherosclerosis development and complications and to arterial aneurysm formation. Finally, the interaction between platelets and tumor cells is strongly influenced by MMPs/TIMPs. All these mechanisms are emerging as important in atherothrombosis, inflammatory disease, and cancer growth and dissemination. Increasing knowledge of these mechanisms may open the way to novel therapeutic approaches.
- Published
- 2017
24. Platelet-targeted pharmacologic treatments as anti-cancer therapy
- Author
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Manuela Sebastiano, Paolo Gresele, Stefania Momi, and Marco Malvestiti
- Subjects
0301 basic medicine ,Platelets ,Blood Platelets ,Cancer Research ,PAR1 antagonists ,Disease ,Bioinformatics ,Metastasis ,03 medical and health sciences ,Aspirin ,Clopidogrel ,Dipyridamole ,GPIIb/IIIa antagonists ,P2Y12 antagonists ,Animals ,Humans ,Neoplasms ,Platelet Aggregation Inhibitors ,Randomized Controlled Trials as Topic ,Oncology ,0302 clinical medicine ,medicine ,Platelet activation ,business.industry ,Cancer ,medicine.disease ,030104 developmental biology ,030220 oncology & carcinogenesis ,Cancer cell ,Immunology ,Platelet aggregation inhibitor ,business ,medicine.drug - Abstract
Platelets act as multifunctional cells participating in immune response, inflammation, allergy, tissue regeneration, and lymphoangiogenesis. Among the best-established aspects of a role of platelets in non-hemostatic or thrombotic disorders, there is their participation in cancer invasion and metastasis. The interaction of many different cancer cells with platelets leads to platelet activation, and on the other hand platelet activation is strongly instrumental to the pro-carcinogenic and pro-metastatic activities of platelets. It is thus obvious that over the last years a lot of interest has focused on the possible chemopreventive effect of platelet-targeted pharmacologic treatments. This article gives an overview of the platelet-targeted pharmacologic approaches that have been attempted in the prevention of cancer development, progression, and metastasis, including the application of anti-platelet drugs currently used for cardiovascular disease and of new and novel pharmacologic strategies. Despite the fact that very promising results have been obtained with some of these approaches in pre-clinical models, with the exclusion of aspirin, clinical evidence of a beneficial effect of anti-platelet agents in cancer is however still largely missing. Future studies with platelet-targeted drugs in cancer must carefully deal with design issues, and in particular with the careful selection of patients, and/or explore novel platelet targets in order to provide a solution to the critical issue of the risk/benefit profile of long-term anti-platelet therapy in the prevention of cancer progression and dissemination.
- Published
- 2017
25. Dipyridamole and PDE Inhibitors
- Author
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Paolo Gresele, Stefania Momi, and Emanuela Falcinelli
- Subjects
Phosphodiesterase 3 ,Guanosine ,Phosphodiesterase ,030204 cardiovascular system & hematology ,Pharmacology ,Adenosine ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,chemistry ,Cell surface receptor ,Second messenger system ,medicine ,Platelet ,030217 neurology & neurosurgery ,Intracellular ,medicine.drug - Abstract
Inhibition of platelet aggregation can be achieved either by the blockade of membrane receptors or by interaction with intracellular signaling pathways. Cyclic adenosine 3′,5′-monophosphate (cAMP) and cyclic guanosine 3′,5-monophosphate (cGMP) are two critical intracellular second messengers provided with strong inhibitory activity on fundamental platelet function. Phosphodiesterases (PDEs), by catalyzing the hydrolysis of cAMP and cGMP, limit the intracellular levels of cyclic nucleotides thus regulating platelet function. The inhibition of PDEs may therefore exert a strong platelet inhibitory effect. In mammalian tissues, 11 structurally related but functionally distinct PDE gene families (PDE1–PDE11) have been described. Platelets possess three PDE isoforms, PDE2, PDE3, and PDE5, with different selectivity for cAMP and cGMP. Several nonselective or isoenzyme-selective PDE inhibitors have been developed, and some of them have entered clinical use as antiplatelet agents. This review will focus on the effect of PDE2, PDE3, and PDE5 inhibitors on platelet function and on the evidence for an antithrombotic action of some of them and in particular of dipyridamole and cilostazol.
- Published
- 2017
26. Platelet amyloid precursor protein is a modulator of venous thromboembolism in mice
- Author
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Gianni Francesco Guidetti, Caterina Visconte, Stefania Momi, Emanuela Falcinelli, Ilaria Canobbio, Marta Zarà, Jessica Canino, Mauro Torti, and Paolo Gresele
- Subjects
0301 basic medicine ,Blood Platelets ,Inferior ,medicine.medical_specialty ,Vena Cava ,Knockout ,Immunology ,Vena Cava, Inferior ,Platelet Glycoprotein GPIIb-IIIa Complex ,Inferior vena cava ,Biochemistry ,Fibrin ,Factor XIa ,03 medical and health sciences ,Amyloid beta-Protein Precursor ,Mice ,0302 clinical medicine ,Internal medicine ,mental disorders ,medicine ,Amyloid precursor protein ,Animals ,Platelet ,Thrombus ,Mice, Knockout ,biology ,Chemistry ,Venous Thromboembolism ,Hematology ,Cell Biology ,Neutrophil extracellular traps ,medicine.disease ,Thrombosis ,030104 developmental biology ,Endocrinology ,medicine.vein ,030220 oncology & carcinogenesis ,Hemostasis ,biology.protein - Abstract
The amyloid precursor protein (APP), primarily known as the precursor of amyloid peptides that accumulate in the brain of patients with Alzheimer disease, is abundant in platelets, but its physiological function remains unknown. In this study, we investigated the role of APP in hemostasis and thrombosis, using APP knockout (KO) mice. Ex vivo aggregation, secretion, and integrin αIIbβ3 inside-out activation induced by several agonists were normal in APP-deficient platelets, but the number of circulating platelets was reduced by about 20%, and their size was slightly increased. Tail bleeding time was normal, and in vivo, the absence of APP did not alter thrombus formation in the femoral artery. In contrast, in a model of vein thrombosis induced by flow restriction in the inferior vena cava, APP-KO mice, as well as chimeric mice with selective deficiency of APP in blood cells, developed much larger thrombi than control animals, and were more sensitive to embolization. Consistent with this, in a pulmonary thromboembolism model, larger vessels were occluded. APP-KO mice displayed a shorter APTT, but not PT, when measured in the presence of platelets. Moreover, the activity of factor XIa (FXIa), but not FXIIa, was higher in APP-KO mice compared with controls. APP-KO mice presented a higher number of circulating platelet-leukocyte aggregates, and neutrophils displayed a greater tendency to protrude extracellular traps, which were more strongly incorporated into venous thrombi. These results indicate that platelet APP limits venous thromboembolism through a negative regulation of both fibrin formation and neutrophil function.
- Published
- 2017
27. Phylogeny of Blood Platelets
- Author
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Viroj Wiwanitkit and Stefania Momi
- Subjects
0301 basic medicine ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Phylogenetics ,Evolutionary biology ,Molecular phylogenetics ,Platelet ,030204 cardiovascular system & hematology ,Biology - Abstract
In biology, phylogenetics is the study of the evolutionary history and relationships among individuals or groups of organisms (e.g., species or populations). At present, molecular phylogenetics is the modern technique for helping with the classification of biological systems. This chapter briefly discusses the phylogeny of blood platelets.
- Published
- 2017
28. A novel mechanism regulating human platelet activation by MMP-2-mediated PAR1 biased signaling
- Author
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Paolo Gresele, Emanuela Falcinelli, Loredana Bury, Marc Hoylaerts, Manuela Sebastiano, and Stefania Momi
- Subjects
0301 basic medicine ,Blood Platelets ,Immunology ,Integrin ,CHO Cells ,Platelet Glycoprotein GPIIb-IIIa Complex ,030204 cardiovascular system & hematology ,Matrix metalloproteinase ,Biochemistry ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,Cricetulus ,Animals ,Humans ,Platelet ,Receptor, PAR-1 ,Platelet activation ,Phosphatidylinositol ,Protein Interaction Maps ,PI3K/AKT/mTOR pathway ,biology ,Chemistry ,Cell Biology ,Hematology ,Platelet Activation ,Cell biology ,030104 developmental biology ,cardiovascular system ,biology.protein ,Phosphorylation ,Matrix Metalloproteinase 2 ,Signal transduction ,Signal Transduction - Abstract
Platelets contain and release several matrix metalloproteinases (MMPs). Among these, active MMP-2 enhances platelet aggregation by favoring the activation of phosphatidylinositol 3- kinase (PI3K) and contributes to arterial thrombosis. The platelet surface target of MMP-2 and the mechanism through which it primes platelets to respond to subsequent stimuli are still unknown. We show that active MMP-2 enhances platelet activation induced by weak stimuli by cleaving PAR1 at a noncanonical extracellular site different from the thrombin-cleavage site and thus initiates biased receptor signaling, triggering only some of the signaling pathways normally activated by full PAR1 agonism. The novel PAR1-tethered ligand exposed by MMP-2 stimulates PAR1-dependent Gq and G12/13 pathway activation, triggering p38-MAPK phosphorylation, Ca+2 fluxes, and PI3K activation, but not Gi signaling; this is insufficient to cause platelet aggregation, but it is enough to predispose platelets to fully respond to Gi-activating stimuli. Integrin αIIbβ3 is a necessary cofactor for PAR1 cleavage by MMP-2 by binding the MMP-2 hemopexin domain, thus favoring the interaction of the enzyme with PAR1. Our studies unravel a novel mechanism regulating platelet activation that involves the binding of MMP-2 to integrin αIIbβ3 and the subsequent cleavage of PAR1 by active MMP-2 at a noncanonical site, exposing a previously undescribed tethered ligand that triggers biased G-protein agonism and thus predisposes platelets to full activation by other stimuli. These results identify the MMP-2-αIIbβ3-PAR1 interaction as a potential target for the prevention of arterial thrombosis.
- Published
- 2016
29. Prevalence of hemostatic alterations in patients with recurrent spontaneous subconjunctival hemorrhage
- Author
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Tiziana Fierro, Sara Orsini, Paolo Gresele, Stefania Momi, Anna Bartolini, Anna Maria Mezzasoma, Carlo Cagini, Emanuela Falcinelli, and Giuseppe Guglielmini
- Subjects
Adult ,Male ,Eye Hemorrhage ,medicine.medical_specialty ,conjunctival disease ,Clinical Biochemistry ,Population ,030204 cardiovascular system & hematology ,blood clotting ,factor XIII ,hemorrhage ,hemostasis ,Gastroenterology ,Hemostatics ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Recurrence ,Internal medicine ,Prevalence ,Von Willebrand disease ,Humans ,Medicine ,Platelet ,Young adult ,education ,Aged ,Aged, 80 and over ,education.field_of_study ,business.industry ,Biochemistry (medical) ,General Medicine ,Middle Aged ,Factor XIII ,medicine.disease ,Surgery ,Hemostasis ,Concomitant ,Female ,Subconjunctival hemorrhage ,business ,030215 immunology ,medicine.drug - Abstract
Background Subconjunctival hemorrage (SCH) is a frequent, mild bleeding manifestation and a common cause of consultation. Hemostatic alterations are possible causes of SCH but their role and prevalence is unknown. We assessed the prevalence of hemostatic abnormalities in patients with spontaneous, recurrent SCH to clarify the role of the hemostasis laboratory in this clinical setting. Methods A total of 105 SCH patients (21-78 years, 65 females) with no identifiable cause (hypertension-trauma-conjunctivitis) or concomitant treatments (NSAIDs- aspirin-oral anticoagulants-antiplatelet agents) and 53 age and sex-matched healthy controls (HCs) (22-72 years, 29 females) were evaluated for skin bleeding time, PFA-100®, blood clotting screening, platelet count, light transmission aggregomery, VWF:Ag, VWF:RCo, RIPA, FVIII activity, FXIII antigen and activity and ISTH Bleeding Severity Score (BSS). Results Prevalence of hemostatic abnormalities was not higher in the SCH population than in HCs BSS was 0.83 (95% CI 0.62-1.06) in SCH and 0.66 (0.37-0.95) in HC (p=NS). Type I Von Willebrand disease was diagnosed in one SCH and none HC patients, a prevalence not significantly different (p=NS by χ2). Conclusions The prevalence of hemostatic alterations in patients with recurrent, spontaneous SCH is not different from the general population; hemostatic screening or second level tests are of no use in patients with recurrent SCH and no other bleedings.
- Published
- 2016
30. Matrix metalloproteinase-2 enhances platelet deposition on collagen under flow conditions
- Author
-
Paolo Gresele, P. G. De Groot, Viviana Appolloni, Giuseppe Guglielmini, Monica Battiston, L De Marco, Stefania Momi, and Emanuela Falcinelli
- Subjects
0301 basic medicine ,Platelet Aggregation ,030204 cardiovascular system & hematology ,Fibrinogen ,Mice ,0302 clinical medicine ,Matrix metalloproteinases ,TIMP-2 ,platelet adhesion ,shear stress ,Platelet ,Whole blood ,Mice, Knockout ,Microscopy ,Microscopy, Confocal ,biology ,Chemistry ,Hematology ,Recombinant Proteins ,Matrix Metalloproteinase 2 ,Collagen ,Shear Strength ,Perfusion ,medicine.drug ,Blood Platelets ,medicine.medical_specialty ,03 medical and health sciences ,Platelet Adhesiveness ,Von Willebrand factor ,Internal medicine ,Platelet adhesiveness ,von Willebrand Factor ,medicine ,Animals ,Humans ,Platelet activation ,Thrombus ,Tissue Inhibitor of Metalloproteinase-2 ,Dose-Response Relationship, Drug ,Thrombosis ,Platelet Activation ,medicine.disease ,lnfectious Diseases and Global Health Radboud Institute for Health Sciences [Radboudumc 4] ,030104 developmental biology ,Endocrinology ,Immunology ,biology.protein ,Stress, Mechanical - Abstract
SummaryPlatelets contain and release matrix metalloproteinase-2 (MMP-2) that in turn potentiates platelet aggregation. Platelet deposition on a damaged vascular wall is the first, crucial, step leading to thrombosis. Little is known about the effects of MMP-2 on platelet activation and adhesion under flow conditions. We studied the effect of MMP-2 on shear-dependent platelet activation using the O’Brien filtration system, and on platelet deposition using a parallel-plate perfusion chamber. Preincubation of human whole blood with active MMP-2 (50 ng/ml, i. e. 0.78 nM) shortened filter closure time (from 51.8 ± 3.6 sec to 40 ± 2.7 sec, p< 0.05) and increased retained platelets (from 72.3 ± 2.3 % to 81.1 ± 1.8 %, p< 0.05) in the O’Brien system, an effect prevented by a specific MMP-2 inhibitor. High shear stress induced the release of MMP-2 from platelets, while TIMP-2 levels were not significantly reduced, therefore, the MMP-2/TIMP-2 ratio increased significantly showing enhanced MMP-2 activity. Preincubation of whole blood with active MMP-2 (0.5 to 50 ng/ml, i.e 0.0078 to 0.78 nM) increased dose-dependently human platelet deposition on collagen under high shear-rate flow conditions (3000 sec-1) (maximum +47.0 ± 11.9 %, p< 0.05, with 50 ng/ml), while pre-incubation with a MMP-2 inhibitor reduced platelet deposition. In real-time microscopy studies, increased deposition of platelets on collagen induced by MMP-2 started 85 sec from the beginning of perfusion, and was abolished by a GPIIb/IIIa antagonist, while MMP-2 had no effect on platelet deposition on fibrinogen or VWF. Confocal microscopy showed that MMP-2 enhances thrombus volume (+20.0 ± 3.0 % vs control) rather than adhesion. In conclusion, we show that MMP-2 potentiates shear-induced platelet activation by enhancing thrombus formation.Supplementary Material to this article is available online at www.thrombosis-online.com.
- Published
- 2016
31. Anti-platelet therapy: phosphodiesterase inhibitors
- Author
-
Paolo Gresele, Stefania Momi, and Emanuela Falcinelli
- Subjects
Pharmacology ,Chemistry ,Phosphodiesterase 3 ,Phosphodiesterase ,Adenosine ,Second messenger system ,medicine ,Platelet aggregation inhibitor ,Pharmacology (medical) ,Platelet ,PDE10A ,Phosphodiesterase inhibitor ,medicine.drug - Abstract
Inhibition of platelet aggregation can be achieved either by the blockade of membrane receptors or by interaction with intracellular signalling pathways. Cyclic adenosine 3′,5′-monophosphate (cAMP) and cyclic guanosine 3′,5′-monophosphate (cGMP) are two critical intracellular second messengers provided with strong inhibitory activity on fundamental platelet functions. Phosphodiesterases (PDEs), by catalysing the hydrolysis of cAMP and cGMP, limit the intracellular levels of cyclic nucleotides, thus regulating platelet function. The inhibition of PDEs may therefore exert a strong platelet inhibitory effect. Platelets possess three PDE isoforms (PDE2, PDE3 and PDE5), with different selectivity for cAMP and cGMP. Several nonselective or isoenzyme-selective PDE inhibitors have been developed, and some of them have entered clinical use as antiplatelet agents. This review focuses on the effect of PDE2, PDE3 and PDE5 inhibitors on platelet function and on the evidence for an antithrombotic action of some of them, and in particular of dipyridamole and cilostazol.
- Published
- 2011
32. Hyperglycemia-Induced Platelet Activation in Type 2 Diabetes Is Resistant to Aspirin but Not to a Nitric Oxide–Donating Agent
- Author
-
Stefania Momi, Paolo Gresele, Paola Lucidi, Geremia B. Bolli, Stefania Marzotti, Silvia Giannini, Pietro Minuz, and Giuseppe Guglielmini
- Subjects
Adult ,Male ,medicine.medical_specialty ,Adolescent ,Platelet Aggregation ,type 2 diabetes mellitus ,platelets ,nitric oxide ,Emerging Treatments and Technologies ,Endocrinology, Diabetes and Metabolism ,Type 2 diabetes ,Nitric oxide ,Young Adult ,chemistry.chemical_compound ,Internal medicine ,Diabetes mellitus ,Internal Medicine ,medicine ,Humans ,Nitric Oxide Donors ,Platelet ,Antipyretic ,Platelet activation ,Original Research ,Aged ,Advanced and Specialized Nursing ,Aspirin ,business.industry ,Middle Aged ,Flow Cytometry ,Platelet Activation ,medicine.disease ,Endocrinology ,chemistry ,Hyperglycemia ,Platelet aggregation inhibitor ,Female ,business ,Platelet Aggregation Inhibitors ,medicine.drug - Abstract
OBJECTIVE Acute, short-term hyperglycemia enhances high shear stress–induced platelet activation in type 2 diabetes. Several observations suggest that platelets in type 2 diabetes are resistant to inhibition by aspirin. Our aim was to assess comparatively the effect of aspirin, a nitric oxide–donating agent (NCX 4016), their combination, or placebo on platelet activation induced by acute hyperglycemia in type 2 diabetes. RESEARCH DESIGN AND METHODS In a double-blind, placebo-controlled, randomized trial, 40 type 2 diabetic patients were allocated to 100 mg aspirin once daily, 800 mg NCX 4016 b.i.d., both of them, or placebo for 15 days. On day 15, 1 h after the morning dose, a 4-h hyperglycemic clamp (plasma glucose 13.9 mmol/l) was performed, and blood samples were collected before and immediately after it for platelet activation and cyclooxygenase-1 (COX-1) inhibition studies. RESULTS Acute hyperglycemia enhanced shear stress–induced platelet activation in placebo-treated patients (basal closure time 63 ± 7.1 s, after hyperglycemia 49.5 ± 1.4 s, −13.5 ± 6.3 s, P < 0.048). Pretreatment with aspirin, despite full inhibition of platelet COX-1, did not prevent it (−12.7 ± 6.9 s, NS vs. placebo). On the contrary, pretreatment with the NO donor NCX 4016, alone or in combination with aspirin, suppressed platelet activation induced by acute hyperglycemia (NCX 4016 +10.5 ± 8.3 s; NCX 4016 plus aspirin: +12.0 ± 10.7 s, P < 0.05 vs. placebo for both). Other parameters of shear stress–dependent platelet activation were also more inhibited by NCX 4016 than by aspirin, despite lesser inhibition of COX-1. CONCLUSIONS Acute hyperglycemia-induced enhancement of platelet activation is resistant to aspirin; a NO-donating agent suppresses it. Therapeutic approaches aiming at a wider platelet inhibitory action than that exerted by aspirin may prove useful in patients with type 2 diabetes.
- Published
- 2010
33. Loss of matrix metalloproteinase 2 in platelets reduces arterial thrombosis in vivo
- Author
-
Silvia Giannini, Stefania Momi, Paolo Gresele, Luca Cecchetti, Teresa Corazzi, Loredana Ruggeri, Emanuela Falcinelli, and Claude Libert
- Subjects
Blood Platelets ,Epinephrine ,Genotype ,Platelet Function Tests ,Immunology ,Pharmacology ,Matrix metalloproteinase ,Article ,Mice ,Bleeding time ,In vivo ,medicine ,Animals ,Humans ,Immunology and Allergy ,Platelet ,Platelet activation ,Thrombus ,medicine.diagnostic_test ,Chemistry ,Thrombosis ,Cell Biology ,Arteries ,Platelet Activation ,medicine.disease ,Mice, Inbred C57BL ,Phenotype ,Hemostasis ,Matrix Metalloproteinase 2 ,Collagen - Abstract
Platelet activation at a site of vascular injury is essential for the arrest of bleeding; however, excessive platelet activation at a site of arterial damage can result in the unwarranted formation of arterial thrombi, precipitating acute myocardial infarction, or ischemic stroke. Activation of platelets beyond the purpose of hemostasis may occur when substances facilitating thrombus growth and stability accumulate. Human platelets contain matrix metalloproteinase 2 (MMP-2) and release it upon activation. Active MMP-2 amplifies the platelet aggregation response to several agonists by potentiating phosphatidylinositol 3-kinase activation. Using several in vivo thrombosis models, we show that the inactivation of the MMP-2 gene prevented thrombosis induced by weak, but not strong, stimuli in mice but produced only a moderate prolongation of the bleeding time. Moreover, using cross-transfusion experiments and wild-type/MMP-2−/− chimeric mice, we show that it is platelet-derived MMP-2 that facilitates thrombus formation. Finally, we show that platelets activated by a mild vascular damage induce thrombus formation at a downstream arterial injury site by releasing MMP-2. Thus, platelet-derived MMP-2 plays a crucial role in thrombus formation by amplifying the response of platelets to weak activating stimuli. These findings open new possibilities for the prevention of thrombosis by the development of MMP-2 inhibitors.
- Published
- 2009
34. Interactions of gallic acid, resveratrol, quercetin and aspirin at the platelet cyclooxygenase-1 level Functional and modelling studies
- Author
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Giovanni de Gaetano, Marilena Crescente, Paolo Gresele, Hans Dieter Höltje, Chiara Cerletti, Stefania Momi, and Gisela Jessen
- Subjects
Blood Platelets ,Male ,Models, Molecular ,Antioxidant ,Platelet Aggregation ,medicine.medical_treatment ,In Vitro Techniques ,Resveratrol ,Models, Biological ,Antioxidants ,Mice ,chemistry.chemical_compound ,Gallic Acid ,Stilbenes ,medicine ,Animals ,Humans ,Drug Interactions ,Gallic acid ,Aspirin ,Arachidonic Acid ,Membrane Proteins ,food and beverages ,Hematology ,chemistry ,Biochemistry ,Polyphenol ,Cyclooxygenase 1 ,Thermodynamics ,Quercetin ,Arachidonic acid ,Reactive Oxygen Species ,Platelet Aggregation Inhibitors ,Salicylic acid ,medicine.drug - Abstract
SummaryWhile resveratrol and quercetin possess antiplatelet activity, little is known on the effect of gallic acid on platelets.We studied the interactions of these three different polyphenols among themselves and with aspirin, at the level of platelet cyclooxygenase-1 (COX-1). Both functional (in vitro and in vivo) and molecular modelling approaches were used. All three polyphenols showed comparable antioxidant activity (arachidonic acid [AA]-induced intraplatelet ROS production); however, resveratrol and quercetin, but not gallic acid, inhibited AA-induced platelet aggregation. Gallic acid, similarly to salicylic acid, the major aspirin metabolite, prevented inhibition of AA-induced platelet function by aspirin but, at variance with salicylic acid, also prevented inhibition by the other two polyphenols. Molecular modelling studies, performed by in silico docking the polyphenols into the crystal structure of COX-1, suggested that all compounds form stable complexes into the COX-1 channel, with slightly different but functionally relevant interaction geometries. Experiments in mice showed that gallic acid administered before aspirin, resveratrol or quercetin fully prevented their inhibitory effect on serum TxB2. Finally, a mixture of resveratrol, quercetin and gallic acid, at relative concentrations similar to those contained in most red wines, did not inhibit platelet aggregation, but potentiated sub-inhibitory concentrations of aspirin. Gallic acid interactions with other polyphenols or aspirin at the level of platelet COX-1 might partly explain the complex,and possibly contrasting, effects of wine and other components of the Mediterranean diet on platelets and on the pharmacologic effect of lowdose aspirin.
- Published
- 2009
35. Resveratrol, at Concentrations Attainable with Moderate Wine Consumption, Stimulates Human Platelet Nitric Oxide Production3
- Author
-
Francesco Violi, Paolo Gresele, Stefania Momi, Andrea Ghiselli, Anna Maria Mezzasoma, Roberto Carnevale, Pasquale Pignatelli, and Giuseppe Guglielmini
- Subjects
Wine ,chemistry.chemical_classification ,Reactive oxygen species ,Nutrition and Dietetics ,NADPH oxidase ,biology ,food and beverages ,Medicine (miscellaneous) ,Resveratrol ,Pharmacology ,biology.organism_classification ,Endothelial NOS ,Nitric oxide ,chemistry.chemical_compound ,chemistry ,Biochemistry ,Enos ,biology.protein ,Platelet - Abstract
The mechanisms through which moderate wine consumption reduces ischemic cardiovascular events are not yet fully unraveled. Grape extracts or a mixture of the polyphenols contained in wine were previously shown to increase nitric oxide (NO); however, little information is available on the effect of resveratrol, one of the main polyphenols of wine, on platelet NO production. We assessed the effects of resveratrol, at the concentrations attainable after moderate wine intake, on platelet NO production and the mechanism of this activity. Twenty healthy volunteers were studied before and after 15 d of controlled white or red wine intake (300 mL/d). After wine intake, plasma resveratrol and the release of NO by stimulated platelets increased significantly. Resveratrol, at the concentrations detected in plasma after wine intake, was incubated in vitro with washed platelets and several variables related to NO production and to signal transduction were measured. Resveratrol in vitro enhanced significantly the production of NO by stimulated platelets, the activity of platelet NO synthase (NOS), phosphorylation of protein kinase B, an activator of the endothelial NOS (eNOS), and phosphorylation of vasodilator-activated protein (VASP), an expression of the biologic activity of NO in platelets. Simultaneously, we observed decreased phosphorylation of P38 mitogen-activated protein kinase (p38MAPK), a proinflammatory pathway in human platelets, a reduction of the activity of NADPH oxidase, a major source of reactive oxygen species (ROS) and of the generation of O(2)(-) radicals, as detected by cytochrome C reduction. In conclusion, resveratrol, at concentrations attainable after moderate wine intake, activates platelet eNOS and in this way blunts the proinflammatory pathway linked to p38MAPK, thus inhibiting ROS production and ultimately platelet function. This activity may contribute to the beneficial effects of moderate wine intake on ischemic cardiovascular disease.
- Published
- 2008
36. Potentiation and priming of platelet activation: a potential target for antiplatelet therapy
- Author
-
Emanuela Falcinelli, Paolo Gresele, and Stefania Momi
- Subjects
Leptin ,Vascular Endothelial Growth Factor A ,Pharmacology ,Effector ,business.industry ,CD40 Ligand ,Priming (immunology) ,Long-term potentiation ,Matrix Metalloproteinase Inhibitors ,Potentiator ,Platelet Activation ,Toxicology ,medicine.disease ,Dinoprostone ,Antithrombotic ,medicine ,Animals ,Humans ,Matrix Metalloproteinase 2 ,Platelet ,Platelet activation ,Thrombus ,business ,Platelet Aggregation Inhibitors - Abstract
Ischemic cardiovascular events represent the leading cause of mortality and morbidity worldwide, and platelet aggregation and thrombus formation are the main effectors of acute arterial ischemic events. Although antiplatelet therapy is the cornerstone of antithrombotic treatment of ischemic cardiovascular disorders, available antiplatelet agents have less than satisfactory efficacy; thus, the identification of novel potential target candidates for antiplatelet therapy is highly warranted. Recent evidence suggests that several molecules that amplify the aggregation response of platelets to activating stimuli, which are either released by platelets (potentiating molecules) or present in the milieu before platelets get activated (primers), play a major role in pathologic thrombus formation without being significantly involved in primary haemostasis. These molecules appear to be a particularly appealing novel potential pharmacologic target for antiplatelet therapy. Here, we review the present knowledge on some molecules acting as potentiators or primers of platelet activation and discuss their possible pharmacologic modulation for antithrombotic purposes.
- Published
- 2008
37. Allergen Induces the Migration of Platelets to Lung Tissue in Allergic Asthma
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Silvia Giannini, Roberta Rossi, Clive P. Page, Stefania Momi, Paolo Gresele, Stefano Baglioni, Lucio Casali, and Simon C. Pitchford
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Blood Platelets ,Male ,Pulmonary and Respiratory Medicine ,Allergy ,Ovalbumin ,Inflammation ,Critical Care and Intensive Care Medicine ,Immunoglobulin E ,Allergic inflammation ,Mice ,Intensive care ,Leukocytes ,medicine ,Animals ,Platelet ,Lung ,medicine.diagnostic_test ,biology ,Receptors, IgE ,business.industry ,Chemotaxis ,Allergens ,respiratory system ,medicine.disease ,Asthma ,Antibodies, Anti-Idiotypic ,respiratory tract diseases ,Bronchoalveolar lavage ,Immunology ,biology.protein ,Bronchial Hyperreactivity ,medicine.symptom ,business - Abstract
Platelets are essential for pulmonary leukocyte recruitment, airway hyperresponsiveness, and bronchial remodeling in animals with allergic inflammation and can be found in bronchoalveolar lavage of sensitized animals. No studies, however, have explored the direct migration of platelets to lungs.To assess whether platelets migrate into lung parenchyma in response to inhaled allergen in ovalbumin-sensitized mice; to assess the role of the FcepsilonRI receptor in this phenomenon; and to evaluate whether platelets from patients with asthma, or from sensitized mice, undergo chemotaxis in vitro in response to relevant antigens.Ovalbumin-sensitized wild-type (WT) mice, or FcRgamma(-/-) mice lacking the FcepsilonRIgamma, were challenged with aerosolized allergen and lungs analyzed by platelet-specific immunohistochemistry. In some experiments, mice were depleted of platelets and cross-transfused with either WT or FcRgamma(-/-) platelets to assess the role of platelet FcRgamma(-/-). Chemotaxis of platelets from patients with asthma or from sensitized mice was studied in vitro.Histology of lungs revealed isolated platelets, migrating out of vessels and localizing underneath the airways after allergen challenge in WT but not in FcRgamma(-/-) mice. Platelets from patients with asthma and from sensitized WT mice, but not from sensitized FcRgamma(-/-) mice, migrated in vitro toward the relevant allergen or an anti-IgE. Platelets from normal mice were found to express FcepsilonRIgamma and platelet-bound IgEs were increased in sensitized mice.Platelets migrate extravascularly in response to a sensitizing allergen via a mechanism dependent on the interaction among allergen, allergen-specific IgE, and the FcepsilonRI, and this may allow them to participate directly in allergic tissue inflammation.
- Published
- 2008
38. RhoA signaling through platelet P2Y1 receptor controls leukocyte recruitment in allergic mice
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Simon C. Pitchford, Paolo Gresele, Stefania Momi, Sandra Keir, Giorgia Manni, Richard T. Amison, Abigail Morris, and Clive P. Page
- Subjects
RHOA ,biology ,Chemistry ,Immunology ,Purinergic receptor ,Allergic inflammation ,P2Y12 ,biology.protein ,Immunology and Allergy ,Platelet ,Platelet activation ,Leukocyte chemotaxis ,Platelet factor 4 - Abstract
Background Clinical studies reveal platelet activation in patients with asthma, allergic rhinitis, and eczema. This is distinct from platelet aggregation, which is critical for the maintenance of hemostasis and in which a role for platelet purinergic receptors is well documented. However, purines are also essential for inflammatory cell trafficking in animal models of allergic lung inflammation, which are known to be platelet dependent, yet the role of purines in the platelet activation accompanying inflammation is unknown. Objectives We investigated whether the involvement of purine activation of platelets during allergic inflammation is distinct from purine involvement in platelet aggregation. Methods BALB/c mice were sensitized to ovalbumin and subsequent airway ovalbumin challenge. Bronchoalveolar lavage fluid was analyzed for inflammatory cells, and blood samples were assessed for platelet activation. The role of platelet purinergic receptors and associated signaling mechanisms (RhoA) were assessed. Results P2Y 1 , but not P2Y 12 or P2X 1 , antagonism inhibited pulmonary leukocyte recruitment. The formation of platelet-leukocyte complexes in vivo and platelet/P-selectin–dependent polymorphonuclear cell migration in vitro were exclusively platelet P2Y 1 receptor dependent. Furthermore, platelet P2Y 1 activation resulted in RhoA activity in vivo after allergen challenge, and RhoA signaling in platelets through P2Y 1 stimulation was required for platelet-dependent leukocyte chemotaxis in vitro . Leukocyte recruitment in thrombocytopenic mice remained suppressed after reinfusion of platelets pretreated with a P2Y 1 antagonist or a Rho-associated kinase 1 inhibitor, confirming the crucial role of platelet P2Y 1 receptor and subsequent activation of RhoA. Conclusion RhoA signaling downstream of platelet P2Y 1 , but not P2Y 12 , represents a clear dichotomy in platelet activation during allergic inflammation versus hemostasis.
- Published
- 2015
39. Visualization of nitric oxide production by individual platelets during adhesion in flowing blood
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Edward Cole Miller, Paolo Gresele, Luigi De Marco, Monica Battiston, Elisabetta Lombardi, Stefania Momi, Maria Rita Cozzi, Giuseppe Guglielmini, Mario Mazzucato, and Denise De Zanet
- Subjects
Blood Platelets ,Male ,Antioxidant ,Arginine ,medicine.medical_treatment ,Immunology ,Nitric Oxide ,Biochemistry ,Nitric oxide ,chemistry.chemical_compound ,Mice ,Platelet Adhesiveness ,medicine ,Animals ,Platelet ,Thrombus ,Enzyme Inhibitors ,Calcium metabolism ,Mice, Knockout ,omega-N-Methylarginine ,Substrate (chemistry) ,Cell Biology ,Hematology ,Adhesion ,medicine.disease ,Fluoresceins ,chemistry ,Quinacrine ,Biophysics ,Calcium ,Collagen ,Blood Flow Velocity - Abstract
Nitric oxide (NO) exerts vasodilatatory, antiplatelet, antioxidant, and antiproliferative effects. Endothelium-derived NO has been shown to be of crucial importance in cardiovascular protection, whereas evidence that NO is synthesized by platelets and regulates platelet function is still controversial. By using a sensitive and specific fluorescent probe, 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM), we visualized NO production in individual platelets undergoing adhesion on a collagen substrate under flow conditions. NO production, monitored in real time, was dependent on the shear rates applied, increasing with the raising of the shear rates. Furthermore, NO production increased in the presence of l-arginine (nitric-oxide synthase [NOS] substrate), and it decreased in the presence of L-NG-monomethyl arginine (L-NMMA) (NOS inhibitor) but not of D-NG-monomethyl arginine (D-NMMA) (L-NMMA-inactive enantiomer). Platelet deposition, measured with mepacrine-labeled platelets, was inversely related to NO production. A correlation was evident between Ca(++) elevation and NO production, suggesting that platelet NO formation is triggered by intracytoplasmic Ca(++) elevation. Simultaneous measurement of NO and Ca(++) indicated that NO production in individual platelets is preceded by Ca(++) elevations, with a lag phase of 33 ± 9.5 s. Our studies provide the first direct demonstration of platelet NO production triggered by the interaction with an activating surface under flow and suggest that intraplatelet Ca(++) elevation elicits the production of NO which, in turn, modulates thrombus size.
- Published
- 2014
40. Nitric oxide-donating aspirin (NCX 4016): an overview of its pharmacological properties and clinical perspectives
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Manlio Bolla, Piero Del Soldato, Stefania Momi, and Paolo Gresele
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Pharmacology ,Aspirin ,business.industry ,cardiovascular disorders ,Inflammation ,Biological activity ,General Medicine ,Disease ,medicine.disease ,Nitric oxide ,chemistry.chemical_compound ,chemistry ,Restenosis ,nitric oxide ,atherothrombosis ,medicine ,Pharmacology (medical) ,In patient ,Myocardial infarction ,medicine.symptom ,business ,medicine.drug - Abstract
In more than a century of use, the benefits of aspirin have been exploited in different therapeutic areas, from inflammation to cardiovascular disease for which it is an approved treatment for acute coronary heart disease and a recommended treatment for secondary cardiovascular prevention in patients at risk. Nitric oxide (NO), a small gaseous free radical molecule, is an important messenger of cellular and biological function that demonstrates an interesting anti-inflammatory profile and vascular protective activity. In addition, NO exerts a protective action on the gastrointestinal mucosa. An elegant approach for exploiting the properties of both aspirin and NO, and for eventually increasing the overall activity of aspirin, has been to create a new molecule in which aspirin and a NO-donating group are covalently linked (NCX 4016). This molecule requires enzymatic metabolism to release both components in order to provide simultaneous actions. NCX 4016 has been shown to retain the anti-inflammatory properties of aspirin and therefore possesses the same efficacy as aspirin in animal models of pain and inflammation. In addition, the release of NO accounts for the inhibition of the release of some cytokines. In cardiovascular models, NCX 4016 shows a better efficacy than aspirin in counteracting thromboembolism, myocardial infarction and vascular reactivity and remodelling (restenosis). This review describes the pharmacological profile of the NO-donating aspirin, NCX 4016, by addressing principally the pharmacological activity in inflammation and cardiovascular models. Gastrointestinal safety is specifically addressed. The potential clinical use of NCX 4016 in vascular pathologies is also discussed.
- Published
- 2005
41. Platelet P-selectin is required for pulmonary eosinophil and lymphocyte recruitment in a murine model of allergic inflammation
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Paolo Gresele, Lucio Casali, Stefania Momi, Simon C. Pitchford, Silvia Giannini, Domenico Spina, and Clive P. Page
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Blood Platelets ,Male ,P-selectin ,Lymphocyte ,Immunology ,Inflammation ,Integrin alpha4beta1 ,Biology ,Granulocyte ,Biochemistry ,Allergic inflammation ,Mice ,Cell Adhesion ,Hypersensitivity ,Leukocytes ,medicine ,Animals ,Platelet ,Lymphocytes ,Lung ,CD11b Antigen ,Cell adhesion molecule ,Chemotaxis ,Cell Biology ,Hematology ,Eosinophil ,Eosinophils ,Mice, Inbred C57BL ,Disease Models, Animal ,P-Selectin ,medicine.anatomical_structure ,medicine.symptom - Abstract
Platelets are necessary for lung leukocyte recruitment in a murine model of allergic inflammation, and platelet–leukocyte aggregates are formed in circulating blood of patients with asthma after allergen exposure. However, it is unknown how platelets induce pulmonary leukocyte recruitment in asthma. Here, we have investigated the importance of platelet adhesion molecule expression on pulmonary eosinophil and lymphocyte recruitment and on leukocyte CD11b and very late antigen (VLA)–4 expression in mice. Pulmonary leukocyte recruitment in platelet-depleted mice (sensitized and exposed to ovalbumin) transfused with fixed, unstimulated platelets (FUSPs) was abolished, whereas transfusion with platelets stimulated and fixed (FSPs), expressing P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1), restored eosinophil and lymphocyte recruitment. Transfusion with platelets from P-selectin–deficient mice, or with FSPs stimulated in the presence of a blocking anti–P-selectin antibody, were unable to restore pulmonary leukocyte recruitment. Flow cytometric analysis revealed increased expression of CD11b and VLA-4 on leukocytes attached to platelets after allergen exposure, and CD11b expression on leukocytes was suppressed in thrombocytopenic mice but was restored with the transfusion of FSPs, but not FUSPs, a phenomenon concurrent with the formation of platelet–leukocyte complexes. P-selectin expression on the surfaces of platelets is a major requirement for pulmonary eosinophil and lymphocyte recruitment, allowing circulating platelets to bind to and stimulate leukocytes for endothelial attachment.
- Published
- 2005
42. Platelets are essential for leukocyte recruitment in allergic inflammation
- Author
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Yanira Riffo-Vasquez, Mark J. Rose, Silvia Giannini, Rebecca Lever, Domenico Spina, Paolo Gresele, Hiroshi Yano, Clive P. Page, Silvia Ciferri, Simon C. Pitchford, Stefania Momi, and Brian J. O'Connor
- Subjects
Adult ,Blood Platelets ,Male ,Neutrophils ,Ovalbumin ,Immunology ,Inflammation ,Granulocyte ,Allergic inflammation ,Mice ,Cell–cell interaction ,Cell Movement ,Cell Adhesion ,Hypersensitivity ,Leukocytes ,Animals ,Humans ,Immunology and Allergy ,Medicine ,Platelet ,Platelet activation ,Peroxidase ,Platelet-poor plasma ,CD11b Antigen ,business.industry ,Allergens ,Immunoglobulin E ,Mice, Inbred C57BL ,N-Formylmethionine Leucyl-Phenylalanine ,medicine.anatomical_structure ,Platelet-rich plasma ,Female ,Endothelium, Vascular ,medicine.symptom ,business - Abstract
Background: The role of platelets in inflammation is recognized but poorly characterized, and little is known of their interaction with leukocytes. However, platelet-leukocyte interactions have been demonstrated in cardiovascular disease, culminating in enhanced leukocyte recruitment. Objectives: This study was undertaken to assess the possibility and potential role of similar phenomena occurring in asthmatic patients, a murine model of allergic inflammation, and in vitro adhesion studies. Methods: Asthmatic patients had blood taken at various time points to document the degree of leukocyte activation and the presence of platelet-leukocyte aggregates through FACS analysis before and after allergen exposure. Similar studies were carried out in mice exposed to allergen after previous sensitization, with some groups being selectively depleted of platelets through both an immunologic (antiplatelet antiserum) and nonimmunologic (busulfan) method. Additionally, lavage fluid and airway tissue were analyzed to assess the degree of pulmonary leukocyte recruitment. The importance of platelets on leukocyte adhesion to the endothelium was then assessed with in vitro incubation of radiolabeled leukocytes in the presence of activated platelets on cultured human vascular endothelial cells. Results: We have observed circulating platelet-leukocyte aggregates in the blood of allergic asthmatic patients during the allergen-induced late asthmatic response and in sensitized mice after allergen exposure. In platelet-depleted mice infiltration of leukocytes into airways after allergen challenge was significantly reduced and could be restored by means of infusion of platelets from allergic animals, indicating an essential role for platelets in leukocyte recruitment. CD11b expression on leukocytes involved in aggregates with platelets, although not on free leukocytes, was upregulated. Furthermore, the presence of autologous platelets augmented the adhesion of human polymorphonuclear leukocytes to cultured vascular endothelial cells, an effect that was found to be endothelial cell dependent and to involve platelet activation. Conclusion: These results suggest that platelet participation in cell recruitment occurs at the level of the circulation and might involve the priming of leukocytes for subsequent adhesion and transmigration into tissues. (J Allergy Clin Immunol 2003;112:109-18.)
- Published
- 2003
43. RhoA signaling through platelet P2Y₁ receptor controls leukocyte recruitment in allergic mice
- Author
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Richard T, Amison, Stefania, Momi, Abigail, Morris, Giorgia, Manni, Sandra, Keir, Paolo, Gresele, Clive P, Page, and Simon C, Pitchford
- Subjects
Blood Platelets ,Platelet Aggregation ,Ovalbumin ,Macrophages ,Allergens ,Models, Biological ,Adenosine Diphosphate ,Chemotaxis, Leukocyte ,Disease Models, Animal ,Mice ,P-Selectin ,Receptors, Purinergic P2Y1 ,Hypersensitivity ,Leukocytes ,Animals ,Female ,Purinergic P2Y Receptor Agonists ,Chemokines ,rhoA GTP-Binding Protein ,Lung ,Signal Transduction - Abstract
Clinical studies reveal platelet activation in patients with asthma, allergic rhinitis, and eczema. This is distinct from platelet aggregation, which is critical for the maintenance of hemostasis and in which a role for platelet purinergic receptors is well documented. However, purines are also essential for inflammatory cell trafficking in animal models of allergic lung inflammation, which are known to be platelet dependent, yet the role of purines in the platelet activation accompanying inflammation is unknown.We investigated whether the involvement of purine activation of platelets during allergic inflammation is distinct from purine involvement in platelet aggregation.BALB/c mice were sensitized to ovalbumin and subsequent airway ovalbumin challenge. Bronchoalveolar lavage fluid was analyzed for inflammatory cells, and blood samples were assessed for platelet activation. The role of platelet purinergic receptors and associated signaling mechanisms (RhoA) were assessed.P2Y₁, but not P2Y₁₂ or P2X₁, antagonism inhibited pulmonary leukocyte recruitment. The formation of platelet-leukocyte complexes in vivo and platelet/P-selectin-dependent polymorphonuclear cell migration in vitro were exclusively platelet P2Y₁ receptor dependent. Furthermore, platelet P2Y₁ activation resulted in RhoA activity in vivo after allergen challenge, and RhoA signaling in platelets through P2Y₁ stimulation was required for platelet-dependent leukocyte chemotaxis in vitro. Leukocyte recruitment in thrombocytopenic mice remained suppressed after reinfusion of platelets pretreated with a P2Y₁ antagonist or a Rho-associated kinase 1 inhibitor, confirming the crucial role of platelet P2Y₁ receptor and subsequent activation of RhoA.RhoA signaling downstream of platelet P2Y₁, but not P2Y₁₂, represents a clear dichotomy in platelet activation during allergic inflammation versus hemostasis.
- Published
- 2014
44. Highly Active Antiretroviral Therapy-related Mechanisms of Endothelial and Platelets Function Alterations
- Author
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Paolo, Gresele, Emanuela, Falcinelli, Stefania, Momi, Daniela, Francisci, and Franco, Baldelli
- Subjects
Blood Platelets ,Inflammation ,Time Factors ,Anti-HIV Agents ,Cardiovascular Diseases ,Risk Factors ,Antiretroviral Therapy, Highly Active ,Animals ,Endothelial Cells ,Humans ,HIV Infections ,Prognosis ,HIV Long-Term Survivors - Abstract
Highly active antiretroviral therapy (HAART) has transformed human immunodeficiency virus (HIV) infection into a chronic condition, which has allowed the infected population to age and become prone to chronic degenerative diseases common to the general population, including atherosclerotic cardiovascular disease, and coronary artery disease (CAD). Possible causative mechanisms of HIV-associated CAD are related to classic cardiovascular risk factors, such as dyslipidemia, insulin resistance, and fat redistribution, which may be due to either HIV infection or to HAART-associated toxicity. However, other mechanisms are emerging as crucial for the cardiovascular complication of HIV and HAART. This article analyzes the effects of HIV and HAART on endothelial function, endothelium-leukocyte interactions, and platelets as possible mechanisms of enhanced cardiovascular risk.
- Published
- 2014
45. Matrix metalloproteinase-2 of human carotid atherosclerotic plaques promotes platelet activation. Correlation with ischaemic events
- Author
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Stefania Momi, Valentina Conti, P de Rango, Paolo Gresele, Marcella Pompili, Teresa Corazzi, Massimo Lenti, Giuseppe Guglielmini, Emanuela Falcinelli, and Gloria Giordano
- Subjects
Carotid Artery Diseases ,medicine.medical_specialty ,Pathology ,Platelet aggregation ,Platelet Aggregation ,medicine.medical_treatment ,030204 cardiovascular system & hematology ,Matrix metalloproteinase ,Matrix Metalloproteinase Inhibitors ,Brain Ischemia ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Thrombin receptor ,Healthy volunteers ,medicine ,Humans ,Zymography ,Platelet ,Platelet activation ,Endarterectomy ,Enzyme Precursors ,Tissue Inhibitor of Metalloproteinase-2 ,Chemistry ,Models, Cardiovascular ,Hematology ,Platelet Activation ,Plaque, Atherosclerotic ,Endocrinology ,Gelatinases ,Matrix Metalloproteinase 2 ,030217 neurology & neurosurgery - Abstract
SummaryPurified active matrix metalloproteinase-2 (MMP-2) is able to promote platelet aggregation. We aimed to assess the role of MMP-2 expressed in atherosclerotic plaques in the platelet-activating potential of human carotid plaques and its correlation with ischaemic events. Carotid plaques from 81 patients undergoing endarterectomy were tested for pro-MMP-2 and TIMP-2 content by zymography and ELISA. Plaque extracts were incubated with gel-filtered platelets from healthy volunteers for 2 minutes before the addition of a subthreshold concentration of thrombin receptor activating peptide-6 (TRAP-6) and aggregation was assessed. Moreover, platelet deposition on plaque extracts immobilised on plastic coverslips under high shear-rate flow conditions was measured. Forty-three plaque extracts (53%) potentiated platelet aggregation (+233 ± 26.8%), an effect prevented by three different specific MMP-2 inhibitors (inhibitor II, TIMP-2, moAb anti-MMP-2). The pro-MMP-2/TIMP-2 ratio of plaques potentiating platelet aggregation was significantly higher than that of plaques not potentiating it (3.67 ± 1.21 vs 1.01 ± 0.43, p
- Published
- 2014
46. Stimulation of platelet nitric oxide production by nebivolol prevents thrombosis
- Author
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Stefano Evangelista, Roberta Caracchini, Paolo Gresele, Emanuela Falcinelli, and Stefania Momi
- Subjects
Blood Platelets ,Male ,Time Factors ,Nitric Oxide Synthase Type III ,medicine.drug_class ,Blood Pressure ,Stimulation ,Vasodilation ,Pharmacology ,Nitric Oxide ,Inhibitory postsynaptic potential ,Antioxidants ,Nebivolol ,Nitric oxide ,Mice ,chemistry.chemical_compound ,Fibrinolytic Agents ,Isomerism ,Selenoprotein P ,Thromboembolism ,medicine ,Animals ,Benzopyrans ,Platelet ,Phosphorylation ,Cyclic GMP ,Mice, Knockout ,Dose-Response Relationship, Drug ,Chemistry ,Thrombosis ,Platelet Activation ,Receptor antagonist ,Adrenergic beta-1 Receptor Antagonists ,Up-Regulation ,Mice, Inbred C57BL ,Disease Models, Animal ,Ethanolamines ,Bisoprolol ,Anesthesia ,Cardiology and Cardiovascular Medicine ,Platelet Aggregation Inhibitors ,medicine.drug - Abstract
Objective— dl -Nebivolol, a selective β1-adrenergic receptor antagonist, besides its hypotensive activity exerts vasodilatory and platelet inhibitory effects in vitro by a mechanism involving nitric oxide (NO). Our aim was to evaluate whether nebivolol exerts in vivo antithrombotic effects, to unravel the mechanism of this action and to clarify the relative roles of its 2 enantiomers: d - and l -nebivolol. Methods and Results— In wild-type mice, dl -nebivolol, l -nebivolol, and d -nebivolol, but not bisoprolol, reduced mortality consequent to platelet pulmonary thromboembolism induced by the intravenous injection of collagen plus epinephrine (−44%, −45%, −29%, respectively; P −/− mice only dl -nebivolol and d -nebivolol were effective. dl -Nebivolol, l - and d -nebivolol reduced photochemical damage-induced femoral artery thrombosis in wild-type mice, whereas in eNOS −/− mice only dl -nebivolol and d -nebivolol were active. Moreover, dl -nebivolol and l -nebivolol increased plasma, urinary-, and platelet-derived nitrites and nitrates (NOx), NO degradation products, in wild-type but not in eNOS −/− mice. In vivo platelet activation, assessed by platelet P-selectin expression, was reduced by dl -nebivolol and l - and d -nebivolol in wild-type mice but only by dl -nebivolol and d -nebivolol in eNOS −/− mice. In bone marrow–transplanted, chimeric mice with only blood cells, and not the endothelium, producing NO dl -nebivolol and l -nebivolol maintained their antithrombotic activity, whereas they lose it in chimeras with only endothelium, and not blood cells, producing NO. In vitro, with isolated platelets, dl -nebivolol and l -nebivolol, but not d -nebivolol and bisoprolol, increased platelet cGMP and NOx formation. Treatment with dl -nebivolol and l -nebivolol increased phophorylated eNOS in platelets. Conclusions— Our data show that dl -nebivolol exerts an antithrombotic activity by stimulating the formation of NO by platelets, and that this effect is generated by its l -enantiomer, whereas the d -enantiomer exerts a weak antiplatelet effect because of β−adrenergic receptor–independent stimulation of adenyly cyclase. These results confirm that platelet-derived NO plays a role in thrombosis prevention and it may represent a target of pharmacological intervention.
- Published
- 2014
47. AB0952 Intra-articular low molecular weight hyaluronate reduces platelet influx and matrix metalloproteinase-2 levels in synovial fluid of patients with knee osteoarthritis
- Author
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Alessia Alunno, Giulia Mirabelli, Eleonora Petito, F. Luccioli, Emanuela Falcinelli, G. Santoboni, Onelia Bistoni, Paolo Gresele, Stefania Momi, Roberto Gerli, and Elena Bartoloni
- Subjects
medicine.medical_specialty ,Pathology ,WOMAC ,business.industry ,Cartilage ,Immunology ,Arthritis ,Osteoarthritis ,medicine.disease ,General Biochemistry, Genetics and Molecular Biology ,chemistry.chemical_compound ,medicine.anatomical_structure ,Endocrinology ,Rheumatology ,chemistry ,Internal medicine ,Hyaluronic acid ,medicine ,Immunology and Allergy ,Synovial fluid ,Platelet ,Platelet activation ,business - Abstract
Background Matrix metalloproteinaeses (MMPs) are a large family of zinc-dependent endoproteinases that cleave several components of the extracellular matrix (ECM) and that are tightly regulated by tissue type MMP inhibitors (TIMPs). The joint cartilage and bone degradation that occurs in osteoarthritis (OA) is in part the consequence of an imbalance between MMPs and TIMPs. MMPs are released by several cell types, including platelets that have been recently shown to participate in the inflammatory processes of arthritis. Among platelet-derived MMPs, MMP-2 is of particular potential relevance for OA. Hyaluronic acid (HA), a core component of ECM, is a critical constituent of normal synovial fluid and plays a pivotal role in joint homeostasis. In clinical practice, intra-articular injection of low molecular weight HA (LMW-HA) has been used as visco-supplementation for knee OA and its therapeutic efficacy has been verified in a number of studies. Objectives Aim of the present study was to investigate the effect of a short treatment with LMW-HA on platelet derived MMP-2 in the synovial fluid and possible correlations with clinical response. Methods Nineteen patients with knee OA were enrolled. Synovial fluid (SF) samples were collected before (T0) and after 5 weeks of intra-articular LMW-HA (T1) (4 injections, one week apart). Western Ontario and McMaster Universities Arthritis Index (WOMAC) and global pain visual analogic scale (VAS) were also collected at both time-points. MMP-2 measurement in SF was performed by zymography. SF inflammatory cell count was performed optically, by a Burker Chamber, while platelets were counted by flow cytometry. Results SF MMP-2 levels, platelet activation, platelet, monocyte and eosinophil numbers, were all significantly reduced at T1, while lymphocyte and synoviocyte number was not affected. A direct correlation between platelet number and MMP-2 concentration in SF was observed at both time-points (p
- Published
- 2014
48. Platelet and endothelial activation in catastrophic and quiescent antiphospholipid syndrome
- Author
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Leonardo Punzi, Alessandro Marturano, Amelia Ruffatti, Silvia Giannini, Ariela Hoxha, Emanuela Falcinelli, Paolo Gresele, Stefania Momi, Vittorio Pengo, A Bontadi, and Marta Tonello
- Subjects
Blood Platelets ,Male ,medicine.medical_specialty ,Endothelium ,CD40 Ligand ,Vascular Cell Adhesion Molecule-1 ,030204 cardiovascular system & hematology ,Catastrophic antiphospholipid syndrome ,Endothelial activation ,03 medical and health sciences ,Mice ,0302 clinical medicine ,Antiphospholipid syndrome ,Pregnancy ,Internal medicine ,von Willebrand Factor ,medicine ,Animals ,Humans ,Platelet ,Platelet activation ,Catastrophic Illness ,Chemokine CCL2 ,030203 arthritis & rheumatology ,Mice, Knockout ,Chemistry ,Receptors, IgG ,Endothelial Cells ,Hematology ,medicine.disease ,Antiphospholipid Syndrome ,Flow Cytometry ,Platelet Activation ,Peptide Fragments ,Mice, Inbred C57BL ,P-Selectin ,Endocrinology ,medicine.anatomical_structure ,beta 2-Glycoprotein I ,Antibodies, Antiphospholipid ,Female ,Selectin ,Ex vivo - Abstract
SummaryAntiphospholipid antibodies (aPL) seem to induce a prothrombotic state by activating endothelium and platelets, but no studies have evaluated systematically the effects of aPL from patients with the antiphospholipid syndrome (APS) in quiescent versus catastrophic phase. Our aims were to evaluate the in vitro effects on platelet activation of anti-β2 glycoprotein I (anti-β2GPI) antibodies isolated from APS patient in either quiescent or catastrophic phase and to investigate ex vivo platelet and endothelial activation in patients with quiescent or catastrophic APS. Anti-β2GPI antibodies were isolated from plasma of a pregnant woman in two different stages of APS (quiescent and catastrophic, respectively). They were co-incubated with washed platelets from healthy controls that were then challenged with TRAP-6 (thrombin receptor activating peptide 6) and the expression of P-selectin (P-sel) on platelets was assessed by flow cytometry. Moreover, plasma samples from six patients with quiescent, four with catastrophic APS and 10 controls were assessed for several markers of platelet and endothelial activation. The results showed that purified anti-β2GPI antibodies co-incubated with platelets enhanced TRAP-6-induced platelet P-sel expression. Notably, anti-β2GPI antibodies isolated during the catastrophic phase enhanced platelet P-sel expression more than antibodies isolated from the same patient in the quiescent stage of disease. Moreover, APS patients had significantly higher plasma levels of soluble (s) Psel, sCD40 ligand, soluble vascular cell adhesion molecule 1 and monocyte chemoattractant protein 1 than control subjects. In addition, sP-sel and von Willebrand factor activity were significantly higher during catastrophic than in quiescent phase.
- Published
- 2013
49. Impaired thrombin-induced platelet activation and thrombus formation in mice lacking the Ca(2+)-dependent tyrosine kinase Pyk2
- Author
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Alessandra Consonni, Paolo Gresele, Mitsuhiko Okigaki, Ilaria Canobbio, Barbara Oliviero, Gianni Francesco Guidetti, Stefania Momi, Mauro Torti, Cesare Balduini, Lina Cipolla, and Marco Falasca
- Subjects
Blood Platelets ,medicine.medical_specialty ,Platelet Aggregation ,Thromboxane ,Immunology ,Fibrinogen ,Group II Phospholipases A2 ,p38 Mitogen-Activated Protein Kinases ,Biochemistry ,Focal adhesion ,Mice ,Thromboxane A2 ,Thrombin ,Internal medicine ,Animals ,Medicine ,Platelet ,Platelet activation ,Phosphorylation ,Mice, Knockout ,business.industry ,Fibrinogen binding ,Thrombosis ,Cell Biology ,Hematology ,Platelet Activation ,Focal Adhesion Kinase 2 ,Endocrinology ,Calcium ,business ,Ex vivo ,Signal Transduction ,medicine.drug - Abstract
In the present study, we used a knockout murine model to analyze the contribution of the Ca2+-dependent focal adhesion kinase Pyk2 in platelet activation and thrombus formation in vivo. We found that Pyk2-knockout mice had a tail bleeding time that was slightly increased compared with their wild-type littermates. Moreover, in an in vivo model of femoral artery thrombosis, the time to arterial occlusion was significantly prolonged in mice lacking Pyk2. Pyk2-deficient mice were also significantly protected from collagen plus epinephrine-induced pulmonary thromboembolism. Ex vivo aggregation of Pyk2-deficient platelets was normal on stimulation of glycoprotein VI, but was significantly reduced in response to PAR4-activating peptide, low doses of thrombin, or U46619. Defective platelet aggregation was accompanied by impaired inside-out activation of integrin αIIbβ3 and fibrinogen binding. Granule secretion was only slightly reduced in the absence of Pyk2, whereas a marked inhibition of thrombin-induced thromboxane A2 production was observed, which was found to be responsible for the defective aggregation. Moreover, we have demonstrated that Pyk2 is implicated in the signaling pathway for cPLA2 phosphorylation through p38 MAPK. The results of the present study show the importance of the focal adhesion kinase Pyk2 downstream of G-protein–coupled receptors in supporting platelet aggregation and thrombus formation.
- Published
- 2013
50. Reperfusion of cerebral artery thrombosis by the GPIb-VWF blockade with the Nanobody ALX-0081 reduces brain infarct size in guinea pigs
- Author
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Paolo Gresele, Giovanni Ricci, Hans Ulrichts, Michela Tantucci, Maarten Van Roy, and Stefania Momi
- Subjects
Brain Infarction ,Male ,Guinea Pigs ,Immunology ,Platelet Glycoprotein GPIIb-IIIa Complex ,Brain damage ,Biochemistry ,Reperfusion therapy ,Fibrinolytic Agents ,Von Willebrand factor ,medicine.artery ,von Willebrand Factor ,Antithrombotic ,medicine ,Animals ,Thrombolytic Therapy ,biology ,business.industry ,Cell Biology ,Hematology ,Tirofiban ,Cerebral Arteries ,Single-Domain Antibodies ,medicine.disease ,Thrombosis ,Disease Models, Animal ,Anesthesia ,Reperfusion ,Middle cerebral artery ,biology.protein ,Intracranial Thrombosis ,medicine.symptom ,business ,Fibrinolytic agent ,medicine.drug - Abstract
Thrombolytic therapy is the cornerstone of treatment of acute atherothrombotic ischemic stroke but is associated with brain hemorrhage; antiplatelet therapy has limited efficacy and is still associated with intracranial bleeding. Therefore, new antithrombotic approaches with a better efficacy/safety ratio are required. We have assessed the effect of ALX-0081, a Nanobody against the A1 domain of von Willebrand factor (VWF) that blocks VWF binding to GPIb, of the thrombolytic agent recombinant tissue plasminogen activator (rtPA), and of the GPIIb/IIIa antagonist tirofiban, in a middle cerebral artery (MCA) thrombosis model in guinea pigs. Drugs were administered before, immediately after, or 15 or 60 minutes after the total occlusion of the MCA. ALX-0081 prevented MCA thrombosis and induced reperfusion when given immediately after and 15 minutes after complete occlusion and reduced brain damage without inducing hemorrhage, whereas tirofiban prevented thrombosis but did not induce reperfusion and induced striking brain hemorrhage. rtPA also induced reperfusion when given 60 minutes after occlusion but provoked brain hemorrhage. Skin bleeding time was not modified or was moderately prolonged by ALX-0081, whereas tirofiban and rtPA prolonged it. The inhibition of the GPIb-VWF axis in guinea pigs prevents cerebral artery thrombosis and induces early reperfusion without provoking intracerebral bleeding thus reducing brain infarct area.
- Published
- 2013
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