Platelet Proinflammatory and Hemostatic Function Is Differentially Regulated in Cystic Fibrosis.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3948-3948
Author(s):  
Alexander Sturm ◽  
Helge Hebestreit ◽  
Ralf Grossmann
Keyword(s):  
Cystic Fibrosis ◽  
Chronic Inflammation ◽  
Platelet Activation ◽  
Platelet Function ◽  
Healthy Controls ◽  
Soluble Cd40 Ligand ◽  
Integrin Αiibβ3 ◽  
Markers Of Inflammation ◽  
Activated Platelets

Abstract Introduction: Platelet function and mechanisms of platelet-leukocyte interactions have been investigated in several vascular und inflammatory disorders. In most studies, platelet activation and an increase of platelet-leukocyte-aggregates (PLA) could be observed. We investigated platelet function in clinically stable patients with cystic fibrosis (CF). Methods: In addition to routine markers of inflammation (e. g. CRP, IgG, ESR) parameters of platelet function were measured in 54 clinically stable CF patients and 55 healthy controls (age range 3 to 41 years): The percentage of P-selectin (CD62P) and PAC-1 (activated integrin αIIbβ3) positive resting and activated platelets (in-vitro activation with the thrombin receptor activating peptide 6) and the number of PLA were determined by flow cytometry. The plasma markers of platelet activation soluble P-selectin (sCD62P) and soluble CD40 ligand (sCD40L) were measured by ELISA. Furthermore, 15 CF patients and 14 healthy controls were investigated to determine CD41a-expression (integrin αIIbβ3) on resting and activated platelets as well as leukocyte expression of P-selectin-glycoprotein ligand 1 (PSGL-1, receptor of CD62P) and integrin αMβ2. Results: Chronic inflammation leads to a decrease of PAC-1-binding to resting and activated platelets. The effects were stronger in patients with higher markers of inflammation. CD41a expression was reduced on in-vitro-activated CF platelets. In contrast, proinflammatory platelet functions remained unchanged (CD62P-expression on resting and activated platelets) or increased (sCD62P, sCD40L, PLA). Leukocyte integrin αMβ2 expression was increased and PSGL-1 expression remained unchanged in CF. Discussion: Platelet function in clinically stable patients with CF is differentially regulated: Chronic inflammation leads to an upregulation of platelet proinflammatory function. In the presence of several procoagulatory mechanisms in inflammation there is a compensatory loss of platelet hemostatic function, shown by the decreased activation and exocytosis of the platelet major integrin αIIbβ3.

A novel role for the fibrinogen Asn-Gly-Arg (NGR) motif in platelet function

2015 ◽  
Vol 113 (02) ◽  
pp. 290-304 ◽  
Author(s):  
Róisín Moriarty ◽  
Ciara A. McManus ◽  
Matthew Lambert ◽  
Thea Tilley ◽  
Marc Devocelle ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Platelet Function ◽  
Platelet Adhesion ◽  
Recognition Sequence ◽  
Integrin Αiibβ3 ◽  
Recognition Motif ◽  
Activated Platelets ◽  
Fibrinogen Binding ◽  
Platelet Spreading

SummaryThe integrin αIIbβ3 on resting platelets can bind to immobilised fibrinogen resulting in platelet spreading and activation but requires activation to bind to soluble fibrinogen. αIIbβ3 is known to interact with the general integrin-recognition motif RGD (arginine–glycine–aspartate) as well as the fibrinogen-specific γ-chain dodecapeptide; however, it is not known how fibrinogen binding triggers platelet activation. NGR (asparagine–glycine–arginine) is another integrin-recognition sequence present in fibrinogen and this study aims to determine if it plays a role in the interaction between fibrinogen and αIIbβ3. NGR-containing peptides inhibited resting platelet adhesion to fibrinogen with an IC50 of 175 μM but failed to inhibit the adhesion of activated platelets to fibrinogen (IC50 > 500 μM). Resting platelet adhesion to mutant fibrinogens lacking the NGR sequences was reduced compared to normal fibrinogen under both static and shear conditions (200 s-1). However, pre-activated platelets were able to fully spread on all types of fibrinogen. Thus, the NGR motif in fibrinogen is the site that is primarily responsible for the interaction with resting αIIbβ3 and is responsible for triggering platelet activation.

scholarly journals Evaluation of the Anticoagulants EDTA and Citrate, Theophylline, Adenosine, and Dipyridamole (CTAD) for Assessing Platelet Activation on the ADVIA 120 Hematology System

2002 ◽  
Vol 48 (6) ◽  
pp. 891-899 ◽  
Author(s):  
Marion Macey ◽  
Urooj Azam ◽  
Desmond McCarthy ◽  
Lee Webb ◽  
E Sabrinah Chapman ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Platelet Activation ◽  
Ex Vivo ◽  
Healthy Controls ◽  
Platelet Volume ◽  
Activated Platelets ◽  
The Mean ◽  
Advia 120 ◽  
Activation Status

Abstract Background: Monitoring of platelet activation by the ADVIA® 120 Hematology System requires an anticoagulant and protocol that ensures that platelets are sphered and their activation status is not altered artifactually in vitro. Methods: Blood from healthy controls was collected into tripotassium EDTA; citrate, theophylline, adenosine, and dipyridamole (CTAD); or a combination of both (E/C) and stored at ambient temperature or at 4 °C (E/C only) and then analyzed between 0 and 180 min later on the ADVIA 120. In addition, immunofluorescent flow cytometry was used to identify activated platelets and platelet-leukocyte aggregates. Results: In blood stored with all three anticoagulants, the platelet count changed little, but the mean platelet volume (MPV) at first decreased and then increased, whereas the mean platelet component (MPC; an indicator of activation) changed in a reciprocal manner. The changes in MPV and MPC, which reflect platelet sphering and swelling, were greatest between 30 and 60 min in blood stored at ambient temperature, irrespective of which anticoagulant was used, and between 60 and 180 min when blood anticoagulated with E/C was stored at 4 °C. In all anticoagulants, the percentages of platelets expressing CD62P and of leukocytes in platelet-leukocyte aggregates increased significantly (P <0.01) over 180 min at ambient temperature. Only minimal (<2%) increases occurred when blood with E/C was stored at 4 °C. Conclusions: When determining platelet activation ex vivo on the ADVIA 120, blood should be collected into E/C, stored at 4 °C, and analyzed between 60 and 180 min later; these conditions ensure maximum platelet sphering without concurrent artifactual platelet activation.

A Comparison of the Effect of Decorsin and Two Disintegrins, Albolabrin and Eristostatin, on Platelet Function

1995 ◽  
Vol 74 (05) ◽  
pp. 1316-1322 ◽  
Author(s):  
Mary Ann McLane ◽  
Jagadeesh Gabbeta ◽  
A Koneti Rao ◽  
Lucia Beviglia ◽  
Robert A Lazarus ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Sequence Similarity ◽  
Platelet Aggregation Inhibitors ◽  
Antiplatelet Drug ◽  
Rgd Sequence ◽  
Fibrinogen Receptor ◽  
Activated Platelets

SummaryNaturally-occurring fibrinogen receptor antagonists and platelet aggregation inhibitors that are found in snake venom (disintegrins) and leeches share many common features, including an RGD sequence, high cysteine content, and low molecular weight. There are, however, significant selectivity and potency differences. We compared the effect of three proteins on platelet function: albolabrin, a 7.5 kDa disintegrin, eristostatin, a 5.4 kDa disintegrin in which part of the disintegrin domain is deleted, and decorsin, a 4.5 kDa non-disintegrin derived from the leech Macrobdella decora, which has very little sequence similarity with either disintegrin. Decorsin was about two times less potent than albolabrin and six times less potent than eristostatin in inhibiting ADP- induced human platelet aggregation. It had a different pattern of interaction with glycoprotein IIb/IIIa as compared to the two disintegrins. Decorsin bound with a low affinity to resting platelets (409 nM) and to ADP-activated platelets (270 nM), and with high affinity to thrombin- activated platelets (74 nM). At concentrations up to 685 nM, it did not cause expression of a ligand-induced binding site epitope on the (β3 subunit of the GPIIb/IIIa complex. It did not significantly inhibit isolated GPIIb/IIIa binding to immobilized von Willebrand Factor. At low doses (1.5-3.0 μg/mouse), decorsin protected mice against death from pulmonary thromboembolism, showing an effect similar to eristostatin. This suggested that decorsin is a much more potent inhibitor of platelet aggregation in vivo than in vitro, and it may have potential as an antiplatelet drug.

Impaired Platelet Function in Sept8-Deficient Mice In Vitro

2020 ◽  
Author(s):  
Kerstin Jurk ◽  
Katharina Neubauer ◽  
Victoria Petermann ◽  
Elena Kumm ◽  
Barbara Zieger
Keyword(s):  
Platelet Function ◽  
Thrombin Generation ◽  
Human Platelets ◽  
Platelet Surface ◽  
Integrin Αiibβ3 ◽  
Glycoprotein Vi ◽  
Fibrinogen Receptor ◽  
Static Conditions ◽  
The Impact

AbstractSeptins (Septs) are a widely expressed protein family of 13 mammalian members, recognized as a unique component of the cytoskeleton. In human platelets, we previously described that SEPT4 and SEPT8 are localized surrounding α-granules and move to the platelet surface after activation, indicating a possible role in platelet physiology. In this study, we investigated the impact of Sept8 on platelet function in vitro using Sept8-deficient mouse platelets. Deletion of Sept8 in mouse platelets caused a pronounced defect in activation of the fibrinogen receptor integrin αIIbβ3, α-granule exocytosis, and aggregation, especially in response to the glycoprotein VI agonist convulxin. In contrast, δ-granule and lysosome exocytosis of Sept8-deficient platelets was comparable to wild-type platelets. Sept8-deficient platelet binding to immobilized fibrinogen under static conditions was diminished and spreading delayed. The procoagulant activity of Sept8-deficient platelets was reduced in response to convulxin as determined by lactadherin binding. Also thrombin generation was decreased relative to controls. Thus, Sept8 is required for efficient integrin αIIbβ3 activation, α-granule release, platelet aggregation, and contributes to platelet-dependent thrombin generation. These results revealed Sept8 as a modulator of distinct platelet functions involved in primary and secondary hemostatic processes.

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.

Platelet Activation and Cytokine Production during Hypothermic Cardiopulmonary Bypass – A Possible Correlation?

1998 ◽  
Vol 80 (07) ◽  
pp. 58-64 ◽  
Author(s):  
P. Ferroni ◽  
G. Speziale ◽  
G. Ruvolo ◽  
A. Giovannelli ◽  
F. M. Pulcinelli ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Cardiopulmonary Bypass ◽  
Inflammatory Response ◽  
Platelet Activation ◽  
Cytokine Production ◽  
Inverse Correlation ◽  
Moderate Degree ◽  
Platelet Response ◽  
Activated Platelets

SummaryCardiopulmonary bypass (CPB) is associated with impaired platelet function and a systemic inflammatory response. The present study was designed to evaluate whether any correlation between platelet activation and inflammatory response during CPB exists. The results obtained from 8 patients undergoing hypothermic CPB for cardiac surgery showed the occurrence of a moderate degree of platelet activation during CPB, demonstrated by an increase of platelet CD62P expression in correlation with an increase of β-thromboglobulin levels, with a concomitant decrease of in vitro platelet response. Plasma IL-1β levels significantly increased during CPB, with a peak between 1 and 4 h after CPB. Similarly, IL-6 levels were elevated 30 min from CPB starting, peaked at 4 h, and remained elevated after 24 h. A direct correlation was found between plasma IL-1β and IL-6 levels. A significant correlation between plasma IL-1β and β-thromboglobulin levels was also found. In turn, plasma β-thromboglobulin levels correlated with CD62P expression on activated platelets. An inverse correlation was found between in vitro platelet aggregation and plasma IL-1β or IL-6 levels. From the present results it may be speculated that platelet activation during CPB may contribute, through the release of IL-1β, to activation of endothelial cells and subsequent release of other cytokines with chemotactic and pro-inflammatory properties, thus playing an important role in the inflammatory response associated with CPB.

A Significant Fraction of ADAMTS13 Activity Is Associated with Activated Platelets and Their Microparticles (PMP): Implication for Regulating ADAMTS13 Activity.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1066-1066
Author(s):  
Wenche Jy ◽  
Andrew Lin ◽  
Loreta Bidot ◽  
Jaehoon Bang ◽  
Eugene Ahn ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Control Level ◽  
In Vitro Study ◽  
Ionophore A23187 ◽  
Adamts13 Activity ◽  
Activated Platelets ◽  
Membrane Bound ◽  
Low Levels

Abstract BACKGROUND: Deficiency of ADAMTS13, vWF cleaving protease, is known to be associated with TTP and some other microangiopathies, but low levels were reported in other diseases such as ITP, DIC, lupus and other thromboses. Although inhibitory autoantibodies were demonstrated in TTP, the mechanisms underlying reduced levels of ADAMTS13 in other disorders remains unclear. We tested the hypothesis that ADAMTS13 is associated with cell membranes and derived microparticles, especially from activated platelet and their microparticles (PMP), which could modulate the enzyme activities of ADAMTS13. METHODS: PRP was prepared by centrifuging citrated normal blood for 10 min at 160×g, and PPP by further centrifuging for 10 min at 3,000×g, and particle-free plasma (PFP) by further centrifuging for 15 min at 20,000×g. ADAMTS13 activity was assayed by the FRETS-VWF73 method of Kokame et al [Br J Haematol 129:93, 2005] using the Fluoroskan Ascent plate reader. Platelets were activated by ADP (10 μM) or ionophore A23187 (2 μM). RESULTS: The ADAMTS13 activity (A) of pooled PPP of 10 controls was defined as 100%. (1) In vitro study: (1a) ADAMTS13 activity was not significantly different between PPP and resting PRP. However, if the platelets in PRP were first activated by ADP for 1hr, a significant reduction of activity was observed (A = 85 ±7%, p<0.05). If the activated platelets were removed, the activity of the supernatant fell to 79 ±10% p<0.05) of the control level, and was further reduced by higher centrifugation to remove PMP (A = 66 ±12%, p<0.01). (1b) Activation by A23187, a stronger agonist producing 2–3 fold more PMP than ADP (confirmed by flow cytometry), induced a more dramatic reduction in PRP (A = 78±8%, p<0.01), and after removal of platelets (A = 71 ±11%, p<0.01), and after removal of PMP (48 ±11%, p<0.01). (1c) Interestingly, resuspending the activated platelets did not restore ADAMTS13 activity, although resuspending the PMP did partially restore the activity. (2) In vivo study: PPP from 13 patients (6 ITP, 4 APS, 3 lupus) were analyzed. The majority (11/13) of PPP samples lost activity after removal of PMP (A = 79 ±12% in PPP vs. 64 ±11% in PFP; p <0.02). CONCLUSION: These data show that a significant but variable fraction of ADAMTS13 activity is associated with activated platelets and PMP. This has several implications. First, distinguishing soluble from membrane-bound ADAMTS13 may lead to better correlation of activities with clinical findings, and may help explain low levels of ADAMTS13 in some disorders associated with platelet activation and high PMP. Second, this interaction may play a role in regulating ADAMTS13 activity. Third, membrane-bound ADAMTS13 may clear more readily from circulation, therefore inhibiting platelet activation or MP formation may have benefits for the management of microangiopathies.

scholarly journals Superoxide Dismutase 2 is dispensable for platelet function

2017 ◽  
Vol 117 (10) ◽  
pp. 1859-1867 ◽  
Author(s):  
Trevor P. Fidler ◽  
Jesse W. Rowley ◽  
Claudia Araujo ◽  
Luc H. Boudreau ◽  
Alex Marti ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Platelet Activation ◽  
Platelet Function ◽  
Mitochondrial Function ◽  
Oxygen Species ◽  
Platelet Dysfunction ◽  
Mitochondrial Ros ◽  
Superoxide Dismutase 2

SummaryIncreased intracellular reactive oxygen species (ROS) promote platelet activation. The sources of platelet-derived ROS are diverse and whether or not mitochondrial derived ROS, modulates platelet function is incompletely understood. Studies of platelets from patients with sickle cell disease, and diabetes suggest a correlation between mitochondrial ROS and platelet dysfunction. Therefore, we generated mice with a platelet specific knockout of superoxide dismutase 2 (SOD2-KO) to determine if increased mitochondrial ROS increases platelet activation. SOD2-KO platelets demonstrated decreased SOD2 activity and increased mitochondrial ROS, however total platelet ROS was unchanged. Mitochondrial function and content were maintained in non-stimulated platelets. However SOD2-KO platelets demonstrated decreased mitochondrial function following thrombin stimulation. In vitro platelet activation and spreading was normal and in vivo, deletion of SOD2 did not change tail-bleeding or arterial thrombosis indices. In pathophysiological models mediated by platelet-dependent immune mechanisms such as sepsis and autoimmune inflammatory arthritis, SOD2-KO mice were phenotypically identical to wildtype controls. These data demonstrate that increased mitochondrial ROS does not result in platelet dysfunction.

Platelet-derived microparticles during and after acute coronary syndrome

2012 ◽  
Vol 107 (06) ◽  
pp. 1122-1129 ◽  
Author(s):  
Mika Skeppholm ◽  
Fariborz Mobarrez ◽  
Karin Malmqvist ◽  
Håkan Wallén
Keyword(s):  
Clinical Trials ◽  
Acute Coronary Syndrome ◽  
Platelet Activation ◽  
Platelet Function ◽  
Plasma Concentrations ◽  
Healthy Controls ◽  
Antithrombotic Treatment ◽  
Coronary Syndrome ◽  
Flow Cytometric ◽  
Cell Fragments

SummaryAs microparticles are shedded upon platelet activation, and may be used to assess platelet function, we measured plasma concentrations of platelet-derived microparticles (PMPs) during and after an acute coronary syndrome (ACS). Fifty-one patients with ACS were investigated at admission, within 24 hours (before coronary angiography), and six months later. Sixty-one sex- and age-matched healthy controls were investigated once. PMPs were defined as particles <1.0 μm in size, negative to phalloidin (labels cell-fragments), and positive to CD61. Exposure of phosphatidylserine (PS+), CD62P and CD142 were also measured. Plasma concentrations of PS+PMPs exposing CD61, CD62P and CD142 were elevated 2.5, 6.0-, and 5.0-fold at admission (p<0.001 for all, compared to controls; aspirin only), decreased significantly 24 hours later following initiation of treatment with clopidogrel and subcutaneous anticoagulation (p<0.001 for all), and decreased even further six months later (p<0.01 for all). However, PS+PMPs exposing CD62P or CD142 were still between 1.2-and 2.3-fold higher than in controls (p<0.001 for both). The pattern for PS−PMPs during and after the ACS was very similar to that for PS+PMPs although the numbers were approximately 1/3 lower. In conclusion, PMP concentrations follow the pattern of platelet activation during and after an ACS. Decreased concentrations are observed after initiation of antithrombotic treatment, but PMP exposing CD62P or CD142 are still elevated after six months. Flow cytometric measurements of PMP in frozen-thawed samples enable studies of platelet function in larger clinical trials.

scholarly journals Platelet Distribution Width Is Associated with P-Selectin Dependent Platelet Function: Results from the Moli-Family Cohort Study

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2737
Author(s):  
Benedetta Izzi ◽  
Alessandro Gialluisi ◽  
Francesco Gianfagna ◽  
Sabatino Orlandi ◽  
Amalia De Curtis ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Platelet Function ◽  
Ex Vivo ◽  
Venous Blood ◽  
Random Effect ◽  
Platelet Distribution Width ◽  
Mixed Effect ◽  
Distribution Width ◽  
Inflammatory Conditions

Defined as an index of platelet size heterogeneity, the platelet distribution width (PDW) is still a poorly characterized marker of platelet function in (sub)clinical disease. We presently validated PDW as a marker of P-selectin dependent platelet activation in the Moli-family cohort. Platelet-bound P-selectin and platelet/leukocyte mixed aggregates were measured by flow cytometry in freshly collected venous blood, both before and after in vitro platelet activation, and coagulation time was assessed in unstimulated and LPS- or TNFα-stimulated whole blood. Closure Times (CT) were measured in a Platelet Function Analyzer (PFA)-100. Multivariable linear mixed effect regression models (with age, sex and platelet count as fixed and family structure as random effect) revealed PDW to be negatively associated with platelet P-selectin, platelet/leukocyte aggregates and von Willebrand factor (VWF), and positively with PFA-100 CT, and LPS- and TNF-α-stimulated coagulation times. With the exception of VWF, all relationships were sex-independent. In contrast, no association was found between mean platelet volume (MPV) and these variables. PDW seems a simple, useful marker of ex vivo and in vitro P-selectin dependent platelet activation. Investigations of larger cohorts will define the usefulness of PDW as a risk predictor of thrombo-inflammatory conditions where activated platelets play a contributing role.

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