Platelet participation in the pathogenesis of dermonecrosis induced by Loxosceles gaucho venom

2015 ◽  
Vol 35 (6) ◽  
pp. 666-676 ◽  
Author(s):  
FL Tavares ◽  
ME Peichoto ◽  
JR Marcelino ◽  
KC Barbaro ◽  
MC Cirillo ◽  
...  
Keyword(s):  
Wound Healing ◽  
Platelet Activation ◽  
Collagen Fiber ◽  
Thrombus Formation ◽  
Spider Venom ◽  
Leukocyte Infiltration ◽  
Platelet Counts ◽  
Normal Platelet ◽  
In Vitro Platelet Activation

Loxosceles gaucho spider venom induces in vitro platelet activation and marked thrombocytopenia in rabbits. Herein, we investigated the involvement of platelets in the development of the dermonecrosis induced by L. gaucho venom, using thrombocytopenic rabbits as a model. L. gaucho venom evoked a drop in platelet and neutrophil counts 4 h after venom injection. Ecchymotic areas at the site of venom inoculation were noticed as soon as 4 h in thrombocytopenic animals but not in animals with initial normal platelet counts. After 5 days, areas of scars in thrombocytopenic animals were also larger, evidencing the marked development of lesions in the condition of thrombocytopenia. Histologically, local hemorrhage, collagen fiber disorganization, and edema were more severe in thrombocytopenic animals. Leukocyte infiltration, predominantly due to polymorphonuclears, was observed in the presence or not of thrombocytopenia. Thrombus formation was demonstrated by immunohistochemistry at the microvasculature, and it occurred even under marked thrombocytopenia. Taken together, platelets have an important role in minimizing not only the hemorrhagic phenomena but also the inflammatory and wound-healing processes, suggesting that cutaneous loxoscelism may be aggravated under thrombocytopenic conditions.

Inhibitory effects of lycopene on in vitro platelet activation and in vivo prevention of thrombus formation

2005 ◽  
Vol 146 (4) ◽  
pp. 216-226 ◽  
Author(s):  
George Hsiao ◽  
Ying Wang ◽  
Nien-Hsuan Tzu ◽  
Tsorng-Hang Fong ◽  
Ming-Yi Shen ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Thrombus Formation ◽  
Inhibitory Effects ◽  
In Vitro Platelet Activation

scholarly journals The secreted tyrosine kinase VLK is essential for normal platelet activation and thrombus formation

2021 ◽  
Author(s):  
Leila Revollo ◽  
Glenn Merrill-Skoloff ◽  
Karen De Ceunynck ◽  
James R. Dilks ◽  
Mattia Bordoli ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Platelet Activation ◽  
Platelet Function ◽  
Secretory Pathway ◽  
Thrombus Formation ◽  
Extracellular Proteins ◽  
Normal Platelet

AbstractTyrosine phosphorylation of extracellular proteins is observed in cell cultures and in vivo, but little is known about the functional roles of tyrosine phosphorylation of extracellular proteins. Vertebrate Lonesome Kinase (VLK) is a broadly expressed secretory pathway tyrosine kinase present in platelet ɑ-granules. It is released from platelets upon activation and phosphorylates substrates extracellularly. Its role in platelet function, however, has not been previously studied. In human platelets, we identified phosphorylated tyrosines mapped to luminal or extracellular domains of transmembrane and secreted proteins implicated in the regulation of platelet activation. To determine the role of VLK in extracellular tyrosine phosphorylation and platelet function, we generated mice with a megakaryocyte/platelet-specific deficiency of VLK. Platelets from these mice are normal in abundance and morphology, but have dramatic changes in function both in vitro and in vivo. Resting and thrombin-stimulated VLK-deficient platelets demonstrate a significant decrease of several tyrosine phosphobands. Functional testing of VLK-deficient platelets shows decreased PAR4- and collagen-mediated platelet aggregation, but normal responses to ADP. Dense granule and α-granule release are reduced in these platelets. Furthermore, VLK-deficient platelets exhibit decreased PAR4-mediated Akt (S473) and Erk1/2(T202/Y204) phosphorylation, indicating altered proximal signaling. In vivo, mice lacking VLK in megakaryocytes/platelets demonstrate strongly reduced platelet accumulation and fibrin formation following laser-injury of cremaster arterioles compared to controls. These studies demonstrate that the secretory pathway tyrosine kinase VLK is critical for stimulus-dependent platelet activation and thrombus formation, providing the first evidence that a secreted protein kinase is required for normal platelet function.

scholarly journals The secreted tyrosine kinase VLK is essential for normal platelet activation and thrombus formation

Blood ◽  
2021 ◽  
Author(s):  
Leila Denise Revollo ◽  
Glenn Merrill-Skoloff ◽  
Karen De Ceunynck ◽  
James R Dilks ◽  
Shihui Guo ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Platelet Activation ◽  
Platelet Function ◽  
Secretory Pathway ◽  
Thrombus Formation ◽  
Extracellular Proteins ◽  
Normal Platelet

Tyrosine phosphorylation of extracellular proteins is observed in cell cultures and in vivo, but little is known about the functional roles of tyrosine phosphorylation of extracellular proteins. Vertebrate Lonesome Kinase (VLK) is a broadly expressed secretory pathway tyrosine kinase present in platelet ɑ-granules. It is released from platelets upon activation and phosphorylates substrates extracellularly. Its role in platelet function, however, has not been previously studied. In human platelets, we identified phosphorylated tyrosines mapped to luminal or extracellular domains of transmembrane and secreted proteins implicated in the regulation of platelet activation. To determine the role of VLK in extracellular tyrosine phosphorylation and platelet function, we generated mice with a megakaryocyte/platelet-specific deficiency of VLK. Platelets from these mice are normal in abundance and morphology, but have significant changes in function both in vitro and in vivo. Resting and thrombin-stimulated VLK-deficient platelets demonstrate a significant decrease of several tyrosine phosphobands. Functional testing of VLK-deficient platelets shows decreased PAR4- and collagen-mediated platelet aggregation, but normal responses to ADP. Dense granule and a-granule release are reduced in these platelets. Furthermore, VLK-deficient platelets exhibit decreased PAR4-mediated Akt (S473) and Erk1/2 (T202/Y204) phosphorylation, indicating altered proximal signaling. In vivo, mice lacking VLK in megakaryocytes/platelets demonstrate strongly reduced platelet accumulation and fibrin formation following laser-injury of cremaster arterioles compared to controls, but normal bleeding times. These studies demonstrate that the secretory pathway tyrosine kinase VLK is critical for stimulus-dependent platelet activation and thrombus formation, providing the first evidence that a secreted protein kinase is required for normal platelet function.

Iohexol, platelet activation and thrombosis

1998 ◽  
Vol 39 (4) ◽  
pp. 349-354 ◽  
Author(s):  
K. S. Sakariassen ◽  
R. M. Barstad ◽  
M. J. A. G. Hamers ◽  
H. Stormorken
Keyword(s):  
Platelet Activation ◽  
Arterial Wall ◽  
Ex Vivo ◽  
Thrombus Formation ◽  
Human Model ◽  
Intravascular Thrombosis ◽  
Platelet Thrombus ◽  
In Vitro Platelet Activation ◽  
Platelet Secretion

Background: The nonionic monomer iohexol triggers in vitro platelet secretion of β-thromboglobulin (β-TG). This iohexol platelet activation may promote intravascular thrombosis. We studied this relationship by employing a human model of collagen-induced platelet thrombus formation at arterial flow. The ionic dimer ioxaglate, the nonionic dimer iodixanol, and glucose were included. Methods and Results: In vitro platelet activation as measured by β-TG secretion following a 1-min incubation of native blood with 50 vol% of iohexol was significant. Glucose solutions of 300, 580 and 825 mosmol, corresponding to the osmolalities of respectively iodixanol, ioxaglate and iohexol, increased the β-TG secretion in parallel with the osmolalities. Ioxaglate and iodixanol were virtually inert. Continuous infusion of iohexol or 580 or 825 mosmol glucose (40 vol%) into flowing native blood at an arterial wall shear rate of 2600 s−1 in an ex vivo collagen-induced platelet thrombus formation device triggered pronounced secretion of β-TG. However, the platelet thrombus formation in blood mixed with iohexol was within the same range as that observed with ioxaglate or iodixanol. Increasing glucose osmolality induced increasing β-TG secretion, which paralleled gradually decreasing platelet thrombus formation. Conclusion: Iohexol and 580 or 825 mosmol glucose trigger platelet secretion of β-TG. This secretion is not associated with enhanced collagen-induced platelet thrombus formation at high arterial shear.

scholarly journals Layer-by-layer coating of stainless steel plates mediated by surface priming treatment to improve antithrombogenic properties

2016 ◽  
Author(s):  
Irene Carmagnola ◽  
Tiziana Nardo ◽  
Francesca Boccafoschi ◽  
Valeria Chiono
Keyword(s):  
Stainless Steel ◽  
Surface Modification ◽  
Platelet Activation ◽  
Colorimetric Assay ◽  
Thrombus Formation ◽  
Human Platelets ◽  
Steel Plates ◽  
Blue Dye ◽  
Layer By Layer

The stainless steel (SS) stents have been used in clinics since 1994. However, typical drawbacks are restenosis and thrombus formation due to limited endothelialisation and hemocompatibility. Surface modification is a smart strategy to enhance antithrombogenicity by promoting endothelialisation. In this work, the layer-by-layer (LbL) technique was applied for coating SS model substrates, after surface priming by functionalisation with 3-aminopropyl triethoxysilane (APTES). A LbL coating made of 14 layers of poly(styrene sulfonate)/poly(diallyldimethylammonium chloride) and heparin as last layer was deposited. FTIR-ATR analysis and contact angle measurements showed that LbL was an effective method to prepare nanostructured coatings. XPS analysis and colorimetric assay employing 1,9-dimethylmethylene blue dye to detect -COOH groups confirmed the successful polyelectrolyte deposition on the coated samples. Preliminary in vitro cell tests, using whole blood and human platelets, were performed to evaluate how surface modification affects platelet activation. Results showed that SS and SS-APTES surfaces induced platelet activation, as indicated by platelet spreading and filopodia formation. After surface modification by LbL coating, the platelets assumed a round shape and no fibrin nets were detected. Data demonstrated that LbL coating is a promising technique to fabricate antithrombogenic surface.

Supplemental Fibrinogen Restores Platelet Inhibitor-Induced Reduction in Thrombus Formation without Altering Platelet Function: An In Vitro Study

2020 ◽  
Vol 120 (11) ◽  
pp. 1548-1556
Author(s):  
Thomas Bärnthaler ◽  
Elisabeth Mahla ◽  
Gabor G. Toth ◽  
Rufina Schuligoi ◽  
Florian Prüller ◽  
...  
Keyword(s):  
Antiplatelet Therapy ◽  
Platelet Activation ◽  
Platelet Function ◽  
Dual Antiplatelet Therapy ◽  
Thrombus Formation ◽  
In Vitro Study ◽  
Coronary Intervention ◽  
Calcium Flux ◽  
Major Surgery

Abstract Background For patients treated with dual antiplatelet therapy, standardized drug-specific 3-to-7 day cessation is recommended prior to major surgery to reach sufficient platelet function recovery. Here we investigated the hypothesis that supplemental fibrinogen might mitigate the inhibitory effects of antiplatelet therapy. Methods and Results To this end blood from healthy donors was treated in vitro with platelet inhibitors, and in vitro thrombus formation and platelet activation were assessed. Ticagrelor, acetylsalicylic acid, the combination of both, and tirofiban all markedly attenuated the formation of adherent thrombi, when whole blood was perfused through collagen-coated microchannels at physiological shear rates. Addition of fibrinogen restored in vitro thrombus formation in the presence of antiplatelet drugs and heparin. However, platelet activation, as investigated in assays of P-selectin expression and calcium flux, was not altered by fibrinogen supplementation. Most importantly, fibrinogen was able to restore in vitro thrombogenesis in patients on maintenance dual antiplatelet therapy after percutaneous coronary intervention. Conclusion Thus, our in vitro data support the notion that supplementation of fibrinogen influences the perioperative hemostasis in patients undergoing surgery during antiplatelet therapy by promoting thrombogenesis without significantly interfering with platelet activation.

Methicillin-Resistant Staphylococcus aureus Induces In Vitro Platelet Activation and a Procoagulant Respons

CHEST Journal ◽  
2011 ◽  
Vol 140 (4) ◽  
pp. 991A
Author(s):  
Zechariah Franks ◽  
Robert Campbell ◽  
Andy Weyrich ◽  
Guy Zimmerman ◽  
Matthew Rondina
Keyword(s):  
Staphylococcus Aureus ◽  
Platelet Activation ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistant ◽  
In Vitro Platelet Activation

scholarly journals IκB kinase 2 is not essential for platelet activation

2020 ◽  
Vol 4 (4) ◽  
pp. 638-643
Author(s):  
Manuel Salzmann ◽  
Sonja Bleichert ◽  
Bernhard Moser ◽  
Marion Mussbacher ◽  
Mildred Haase ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Active Site ◽  
Bleeding Time ◽  
Thrombus Formation ◽  
Human Platelets ◽  
Iκb Kinase ◽  
Specific Deletion

Abstract Platelets are small anucleate cells that release a plethora of molecules to ensure functional hemostasis. It has been reported that IκB kinase 2 (IKK2), the central enzyme of the inflammatory NF-κB pathway, is involved in platelet activation, because megakaryocyte/platelet-specific deletion of exons 6 and 7 of IKK2 resulted in platelet degranulation defects and prolonged bleeding. We aimed to investigate the role of IKK2 in platelet physiology in more detail, using a platelet-specific IKK2 knockout via excision of exon 3, which makes up the active site of the enzyme. We verified the deletion on genomic and transcriptional levels in megakaryocytes and were not able to detect any residual IKK2 protein; however, platelets from these mice did not show any functional impairment in vivo or in vitro. Bleeding time and thrombus formation were not affected in platelet-specific IKK2-knockout mice. Moreover, platelet aggregation, glycoprotein GPIIb/IIIa activation, and degranulation were unaltered. These observations were confirmed by pharmacological inhibition of IKK2 with TPCA-1 and BMS-345541, which did not affect activation of murine or human platelets over a wide concentration range. Altogether, our results imply that IKK2 is not essential for platelet function.

A Role for Bile Salt-Dependent Lipase in Platelet Activation and in Thrombus Formation in Vivo.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3526-3526 ◽  
Author(s):  
Laurence Panicot-Dubois ◽  
Christophe Dubois ◽  
Barbara C. Furie ◽  
Bruce Furie ◽  
Dominique Lombardo
Keyword(s):  
Bile Salt ◽  
Platelet Activation ◽  
Thrombus Formation ◽  
Pancreatic Acinar Cells ◽  
Cremaster Muscle ◽  
Terminal Domain ◽  
Laser Injury ◽  
Phosphatidylserine Exposure

Abstract Bile Salt Dependent Lipase (BSDL) is an enzyme secreted by pancreatic acinar cells. BSDL, in the presence of primary bile salts, participates in the hydrolysis of dietary lipid esters in the duodenum lumen. This 105 kDa N and O-glycosylated protein has been detected in the plasma of normal subjects. Recent in vitro and in vivo studies demonstrated that pancreatic BSDL reaches the blood via transcytosis through enterocytes. Other studies showed that pancreatic human BSDL is captured by human umbilical vein endothelial cells and induces the proliferation of smooth muscle cells in vitro at BSDL concentrations found in blood, suggesting that this enzyme may play a role in hemostasis and thrombosis. However the specific role of circulating BSDL is unknown. The goal of this study was to determine the possible involvement of circulating BSDL in thrombus formation. We investigated the participation of circulating mouse BSDL in thrombus formation using widefield intravital microscopy in the cremaster muscle of living mice. Thrombi were formed following laser injury of the vessel wall of an arteriole in the cremaster muscle. Pancreatic mouse BSDL, a 74 kDa glycoprotein, was detected using several antibodies directed against either the whole human BSDL (pAbL64, pAbL32) or a peptide based on a sequence in the N-terminal domain of BSDL (Ser326-Thr350; pAbAntipeptide). Mouse and human BSDL share about 80% sequence homology, the main difference localized in the C-terminal domain, which is truncated to the mouse BSDL compared with the human enzyme. All the antibodies are able to specifically recognize the mouse pancreatic BSDL. Using antibodies pAbL64, pAbL32, or pAbAntipeptide we observed specific accumulation of circulating mouse BSDL into the growing thrombus. The circulating BSDL co-localized with platelets present in the thrombus. These results suggest that circulating BSDL is involved in thrombus formation in vivo. In order to determine if BSDL plays a role in platelet activation and aggregation, we performed in vitro studies on human washed platelets. BSDL increased both the amount of phosphatidylserine exposure on the surface of platelets and the activation of αIIbβ3 induced by thrombin. These results indicate that this enzyme can amplify the activation of platelets in vitro. While BSDL alone cannot induce the aggregation of platelets, this enzyme significantly increases the amount of platelet aggregation induced by SFLLRN peptide or thrombin. Altogether, these data suggeste that circulating BSDL participates in the thrombus formation after laser injury of the arterial wall and can amplify both the activation of platelets and the phosphatidylserine exposure, increasing the thrombotic response after vessel injury. This mechanism may be operative in the development of venous thromboembolic disease in pancreatic cancer.

Sign in / Sign up

Export Citation Format

Share Document