scholarly journals Silica Nanoparticles Effects on Blood Coagulation Proteins and Platelets

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Volodymyr Gryshchuk ◽  
Natalya Galagan
Keyword(s):  
Silica Nanoparticles ◽  
Blood Coagulation ◽  
Platelet Rich Plasma ◽  
Drug Carriers ◽  
Human Platelets ◽  
Factor X ◽  
Activated Platelets ◽  
Haemostatic Agents ◽  
Coagulation Proteins

Interaction of nanoparticles with the blood coagulation is important prior to their using as the drug carriers or therapeutic agents. The aim of present work was studying of the primary effects of silica nanoparticles (SiNPs) on haemostasisin vitro. We studied the effect of SiNPs on blood coagulation directly estimating the activation of prothrombin and factor X and to verify any possible effect of SiNPs on human platelets. It was shown that SiNPs shortened coagulation time in APTT and PT tests and increased the activation of factor X induced by RVV possibly due to the sorption of intrinsic pathway factors on their surface. SiNPs inhibited the aggregation of platelet rich plasma induced by ADP but in the same time partially activated platelets as it was shown using flow cytometry. The possibility of SiNPs usage in nanomedicine is strongly dependant on their final concentration in bloodstream and the size of the particles that are used. However SiNPs are extremely promising as the haemostatic agents for preventing the blood loss after damage.

Functional Characterization of PM6/13, a β3-specific (GPIIIa/CD61) Monoclonal Antibody that Shows Preferential Inhibition of Fibrinogen Binding over Fibronectin Binding to Activated Human Platelets

1998 ◽  
Vol 79 (01) ◽  
pp. 177-185 ◽  
Author(s):  
Ashia Siddiqua ◽  
Michael Wilkinson ◽  
Vijay Kakkar ◽  
Yatin Patel ◽  
Salman Rahman ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
Functional Characterization ◽  
Human Platelets ◽  
Western Blots ◽  
Activated Platelets ◽  
Reducing Conditions ◽  
Fibronectin Binding

SummaryWe report the characterization of a monoclonal antibody (MAb) PM6/13 which recognises glycoprotein IIIa (GPIIIa) on platelet membranes and in functional studies inhibits platelet aggregation induced by all agonists examined. In platelet-rich plasma, inhibition of aggregation induced by ADP or low concentrations of collagen was accompanied by inhibition of 5-hydroxytryptamine secretion. EC50 values were 10 and 9 [H9262]g/ml antibody against ADP and collagen induced responses respectively. In washed platelets treated with the cyclooxygenase inhibitor, indomethacin, PM6/13 inhibited platelet aggregation induced by thrombin (0.2 U/ml), collagen (10 [H9262]g/ml) and U46619 (3 [H9262]M) with EC50 = 4, 8 and 4 [H9262]g/ml respectively, without affecting [14C]5-hydroxytryptamine secretion or [3H]arachidonate release in appropriately labelled cells. Studies in Fura 2-labelled platelets revealed that elevation of intracellular calcium by ADP, thrombin or U46619 was unaffected by PM6/13 suggesting that the epitope recognised by the antibody did not influence Ca2+ regulation. In agreement with the results from the platelet aggregation studies, PM6/13 was found to potently inhibit binding of 125I-fibrinogen to ADP activated platelets. Binding of this ligand was also inhibited by two other MAbs tested, namely SZ-21 (also to GPIIIa) and PM6/248 (to the GPIIb-IIIa complex). However when tested against binding of 125I-fibronectin to thrombin stimulated platelets, PM6/13 was ineffective in contrast with SZ-21 and PM6/248, that were both potent inhibitors. This suggested that the epitopes recognised by PM6/13 and SZ-21 on GPIIIa were distinct. Studies employing proteolytic dissection of 125I-labelled GPIIIa by trypsin followed by immunoprecipitation with PM6/13 and analysis by SDS-PAGE, revealed the presence of four fragments at 70, 55, 30 and 28 kDa. PM6/13 did not recognize any protein bands on Western blots performed under reducing conditions. However Western blotting analysis with PM6/13 under non-reducing conditions revealed strong detection of the parent GP IIIa molecule, of trypsin treated samples revealed recognition of an 80 kDa fragment at 1 min, faint recognition of a 60 kDa fragment at 60 min and no recognition of any product at 18 h treatment. Under similar conditions, SZ-21 recognized fragments at 80, 75 and 55 kDa with the 55kDa species persisting even after 18 h trypsin treatment. These studies confirm the epitopes recognised by PM6/13 and SZ-21 to be distinct and that PM6/13 represents a useful tool to differentiate the characteristics of fibrinogen and fibronectin binding to the GPIIb-IIIa complex on activated platelets.

Reaction of Acetaldehyde with Human Platelets

1992 ◽  
Vol 67 (01) ◽  
pp. 126-130 ◽  
Author(s):  
Olivier Spertini ◽  
Jacques Hauert ◽  
Fedor Bachmann
Keyword(s):  
Platelet Aggregation ◽  
Inhibitory Action ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Shape Change ◽  
Reaction Medium ◽  
Human Platelets ◽  
Membrane Glycoproteins ◽  
Neutral Ph

SummaryPlatelet function defects observed in chronic alcoholics are not wholly explained by the inhibitory action of ethanol on platelet aggregation; they are not completely reproduced either in vivo by short-term ethanol perfusion into volunteers or in vitro by the addition of ethanol to platelet-rich plasma. As acetaldehyde (AcH) binds to many proteins and impairs cellular activities, we investigated the effect of this early degradation product of ethanol on platelets. AcH formed adducts with human platelets at neutral pH at 37° C which were stable to extensive washing, trichloracetic acid hydrolysis and heating at 100° C, and were not reduced by sodium borohydride. The amount of platelet adducts formed was a function of the incubation time and of the concentration of AcH in the reaction medium. At low AcH concentrations (<0.2 mM), platelet bound AcH was directly proportional to the concentration of AcH in the reaction medium. At higher concentrations (≥0.2 mM), AcH uptake by platelets tended to reach a plateau. The amount of adducts was also proportional to the number of exposures of platelets to pulses of 20 pM AcH.AcH adducts formation severely impaired platelet aggregation and shape change induced by ADP, collagen and thrombin. A positive correlation was established between platelet-bound AcH and inhibition of aggregation.SDS-PAGE analysis of AcH adducts at neutral pH demonstrated the binding of [14C]acetaldehyde to many platelet proteins. AcH adduct formation with membrane glycoproteins, cytoskeleton and enzymes might interfere with several steps of platelet activation and impair platelet aggregation.This in vitro study shows that AcH has a major inhibitory action on platelet aggregation and may account for the prolonged ex vivo inhibition of aggregation observed in chronic alcoholics even in the absence of alcoholemia.

Interactions of Staphylokinase with Human Platelets

1995 ◽  
Vol 73 (03) ◽  
pp. 472-477 ◽  
Author(s):  
H R Lijnen ◽  
B Van Hoef ◽  
D Collen
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Specific Binding ◽  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Normal Plasma ◽  
Atp Secretion ◽  
Platelet Disaggregation ◽  
Activation Rate

SummaryThe interactions of recombinant staphylokinase (SakSTAR) with human platelets were investigated in a buffer milieu, in a human plasma milieu in vitro, and in plasma from patients with acute myocardial infarction (AMI) treated with SakSTAR.In a buffer milieu, the activation rate of plasminogen by SakSTAR or streptokinase (SK) was not significantly altered by addition of platelets. Specific binding of SakSTAR or SK to either resting or thrombin- activated platelets was very low. ADP-induced or collagen-induced platelet aggregation in platelet-rich plasma (PRP) was 94 ± 2.7% or 101 ± 1.7% of control in the presence of 0.1 to 20 μM SakSTAR, with corresponding values of 95 ± 2.8% or 90 ± 4.6% of control in the presence of 0.1 to 4 μM SK. No effects were observed on platelet disaggregation. ATP secretion following collagen-induced platelet aggregation was 4.3 ± 0.26 μM for SakSTAR (at concentrations of 0.1 to 20 μM) and 4.4 ± 0.35 μM for SK (at concentrations of 0.1 to 4 μM), as compared to 3.4 ± 0.70 μM in the absence of plasminogen activator.Fifty % lysis in 2 h (C50) of 60 μl 125I-fibrin labeled platelet-poor plasma (PPP) clots prepared from normal plasma or from plasma of patients with Glanzmann thrombasthenia and immersed in 0.5 ml normal plasma, was obtained with 12 or 16 nM SakSTAR and with 49 or 40 nM SK, respectively. C50 values for lysis of 60 μl PRP clots prepared from normal or patient plasma were also comparable for SakSTAR (19 or 21 nM), whereas SK was 2-fold more potent toward PRP clots prepared from Glanzmann plasma as compared to normal plasma (C50 of 130 versus 270 nM).No significant effect of SakSTAR on platelet function was observed in plasma from patients with AMI treated with SakSTAR, as revealed by unaltered platelet count, platelet aggregation and ATP secretion.Thus, no effects of high SakSTAR concentrations were observed on human platelets in vitro, nor of therapeutic SakSTAR concentrations on platelet function in plasma.

scholarly journals Evaluating biological activity of folic acid-modified and 10-hydroxycamptothecin-loaded mesoporous silica nanoparticles

2021 ◽  
Author(s):  
Mei-Xia Zhao ◽  
Di-Feng Chen ◽  
Xue-Jie Zhao ◽  
Lin-Song Li ◽  
Yong-Fang Liu
Keyword(s):  
Folic Acid ◽  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Folate Receptor ◽  
Mesoporous Silica Nanoparticles ◽  
Drug Carriers ◽  
Transmission Electron ◽  
Before And After ◽  
Drug Efficiency

Targeted nanocarrier can selectively deliver anti-tumor drugs to cancer sites improving drug efficiency. Accordingly, a targeted nanocarrier (MSN-FA) was synthesized based on folic acid (FA) modified mesoporous silica nanoparticles (MSNs). These loaded with 10-hydroxycamptothecin (HCPT) to obtain the nano-drug MSN-FA@HCPT. These nanocarriers were characterized by transmission electron microscopy (TEM), zeta potential, ultraviolet-visible spectroscopy (UV-Vis), fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). Notably, the nanocarriers were nearly spherical before and after loading HCPT and exhibited good dispersibility. Also, folate receptor (FR) over-expressing HeLa cells and FR deficient HepG2 cells were used to evaluate in vitro cellular uptake and cytotoxicity of MSN-FA@HCPT and MSN@HCPT. Interestingly, FA-modified nanocarriers enhanced the cytotoxicity of HCPT by improving drug targeting to tumor cells. Also, apoptotic and mitochondrial membrane potential (MMP) reducing effects of MSN-FA@HCPT were more prominent than the MSNs without FA modification. MSN-FA@HCPT can be excellent drug carriers with profound biomedical applications.

Arginine vasopressin release from human platelets after irreversible aggregation

1990 ◽  
Vol 78 (1) ◽  
pp. 113-116 ◽  
Author(s):  
Giovanni Anfossi ◽  
Elena Mularoni ◽  
Mariella Trovati ◽  
Paola Massucco ◽  
Luigi Mattiello ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Arginine Vasopressin ◽  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Vasopressin Release ◽  
Irreversible Aggregation ◽  
Local Release

1. The release of arginine vasopressin from human platelets was investigated in platelet-rich plasma after irreversible aggregation induced by adenosine 5′-pyrophosphate, collagen, sodium arachidonate, thrombin and adrenaline in vitro. 2. Arginine vasopressin levels were significantly higher in the supernatant from stimulated platelet-rich plasma than from unstimulated samples, reaching 3.5 × 10−12 (range 1.6–12.5 × 10−12) mol/l in the absence of an aggregating agent, 8.8 × 10−12 (range 4.2–17.5 × 10−12) mol/l after adenosine 5′-pyrophosphate, 13.7 × 10−12 (2.2–63.2 × 10−12) mol/l after collagen, 7.8 × 10−12 (2.2–14.6 × 10−12) mol/l after sodium arachidonate, 7.8 × 10−12 (2.2–16.3 × 10−12) mol/l after thrombin and 12.2 × 10−12 (4.8–32.1 × 10−12) mol/l after adrenaline. 3. An arginine vasopressin level of 18 × 10−12 mol/l, which can be achieved physiologically, increased the sensitivity of platelets to adenosine 5′-pyrophosphate and collagen in vitro; the same concentration of arginine vasopressin caused a potentiation of the effect of catecholamines on the response of platelets to sodium arachidonate. 4. These results indicate that intraplatelet arginine vasopressin is released during aggregation and suggest that a local release of arginine vasopressin could occur after complete platelet aggregation in vivo.

Endotoxin-Induced Platelet Activation in Human Whole Blood In Vitro

1988 ◽  
Vol 59 (03) ◽  
pp. 378-382 ◽  
Author(s):  
Gyorgy Csako ◽  
Eva A Suba ◽  
Ronald J Elin
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Atp Release ◽  
Human Platelets ◽  
Lag Phase ◽  
Human Whole Blood ◽  
Dose Dependent

SummaryThe effect of purified bacterial endotoxin was studied on human platelets in vitro. In adding up to 1 μg/mL of a highly purified endotoxin, we found neither aggregation nor ATP release in heparinized or citrated human platelet-rich plasma. On the other hand, endotoxin at concentrations as low as a few ng/mL (as may be found in septic patients) caused platelet aggregation in both heparinized and citrated human whole blood, as monitored by change in impedance, free platelet count, and size. Unlike collagen, the platelet aggregation with endotoxin occurred after a long lag phase, developed slowly, and was rarely coupled with measurable release of ATP. The platelet aggregating effect of endotoxin was dose-dependent and modified by exposure of the endotoxin to ionizing radiation. Thus, the activation of human platelets by “solubilized” endotoxin in plasma requires the presence of other blood cells. We propose that the platelet effect is mediated by monocytes and/or neutrophils stimulated by endotoxin.

The platelet strip. I. A low-fibrin contractile model of thrombin-activated platelets

1985 ◽  
Vol 249 (3) ◽  
pp. C279-C287 ◽  
Author(s):  
L. Salganicoff ◽  
M. H. Loughnane ◽  
R. W. Sevy ◽  
M. Russo
Keyword(s):  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Pharmacological Agents ◽  
Nylon Mesh ◽  
Giant Platelet ◽  
Activated Platelets ◽  
Full Relaxation ◽  
Platelet Aggregate ◽  
Thrombin Activation ◽  
Isometric Forces

The ultrastructure and contractile behavior of a new preparation of thrombin-activated human platelets is described. The preparation is referred to as the "platelet strip" because of its similarities to classical vascular smooth muscle strips. The platelet strip consists of a giant platelet aggregate 10 mm long, 4 mm wide, and 200 micron thick. To facilitate handling, the aggregate has a special high-compliance nylon mesh embedded in its mass. Each strip contains 7.3 X 10(8) platelets. Fibrin contamination is 150-fold lower than in platelet-rich plasma clots. Active isometric forces of up to 100 g/cm2 and 6-10 h viability are easily and reproducibly obtained. Platelet strips remain contracted after thrombin activation. The contraction is tonic and partial. Further small increases in force can be produced by depolarizing solutions or pharmacological agents, e.g., ADP, epinephrine, and endoperoxide analogues. These small increases are reversible on washout of the agents. Full relaxation is induced by agents such as prostaglandin E1 or papaverine, which increase adenosine 3',5'-cyclic monophosphate. However, after washout of these agents, recovery of tension is variable depending on the concentration of the drug and the degree of prestretching of the preparation.

Effects of gas bubbling and other forms of convection on platelets in vitro

1989 ◽  
Vol 67 (3) ◽  
pp. 1250-1255 ◽  
Author(s):  
D. M. Pickles ◽  
D. Ogston ◽  
A. G. MacDonald
Keyword(s):  
Shear Stress ◽  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Air Plasma ◽  
Physiological Level ◽  
Gentle Agitation ◽  
Rocking Motion ◽  
Experimental Treatments ◽  
Induced Aggregation

Citrated platelet-rich human plasma was subjected to one of three experimental treatments at 37 degrees C for 15 min: stirring, bubbling (with stirring), and gentle agitation achieved by a rocking motion. The last two were “equiconvective” as judged by equilibration rates with CO2 and O2 but presumably differed in the shear stress they imposed on the cells. Stirring platelets in normal air or 5% CO2-air caused no significant aggregation. Bubbling air through platelet-rich plasma increased its pH and marked aggregation occurred. Bubbling CO2-air caused the platelet-rich plasma pH to attain its physiological level of 7.4 with less aggregation. In both cases, subsequent ADP-induced aggregation was diminished. Rocking (without stirring) in the presence of CO2-air caused negligible aggregation in platelets and an enhanced response to ADP. Because of the marked difference between the two equiconvective treatments, bubbling and rocking, the main factor in activating the human platelets is suggested to be shear stress (potentiated by high pH), with perhaps a lesser contribution from the air-plasma interface.

Platelet microparticle membranes have 50- to 100-fold higher specific procoagulant activity than activated platelets

2007 ◽  
Vol 97 (03) ◽  
pp. 425-434 ◽  
Author(s):  
Dmitry Kireev ◽  
Nadezhda Popenko ◽  
Aleksei Pichugin ◽  
Mikhail Panteleev ◽  
Olga Krymskaya ◽  
...  
Keyword(s):  
Blood Platelets ◽  
Calcium Ionophore ◽  
Coagulation Factors ◽  
In Vitro Models ◽  
Calcium Ionophore A23187 ◽  
Procoagulant Activity ◽  
Ionophore A23187 ◽  
Factor X ◽  
Activated Platelets

SummaryPlatelet microparticles (PMPs) are small vesicles released from blood platelets upon activation. The procoagulant activity of PMPs has been previously mainly characterized by theirability to bind coagulation factors VIII and Va in reconstructed systems. It can be supposed that PMPs can contribute to the development of thrombotic complications in the pathologic states associated with the increase of their blood concentration. In this study we compared procoagulant properties of calcium ionophore A23187-activated platelets and PMPs using several in-vitro models of hemostasis. Surface densities of phosphatidylserine, CD61, CD62P and factor X bound per surface area unit were determined by flow cytometry. They were 2.7-, 8.4-, 4.3-, and 13-fold higher for PMPs than for activated platelets, respectively. Spatial clot growth rate (Vclot) in the reaction-diffus ion experimental model and endogenous thrombin potential (ETP) were determined in plasma, which was depleted of phospholipid cell surfaces by ultra-centrifugation and supplemented with activated platelets or PMPs at different concentrations. Both Vcllot and ETP rapidly increased with the increase of PMP or platelet concentration until saturation was reached. The plateau values of Vclot and ETP for activated platelets and PMPs were similar. In both assays, the procoagulant activity of one PMP was almost equal to that of one activated platelet despite at least two-orders-of-magnitude difference in their surface areas. This suggests that the PMP surface is approximately 50- to 100-fold more procoagulant than the surface of activated platelets.

Effect of Heparin on Aggregation, Release Reaction and Thromboxane A2synthesis in Human Platelets

1979 ◽  
Author(s):  
H.Y.K. Chuang ◽  
S.F. Mohammad ◽  
R.G. Mason
Keyword(s):  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
Thromboxane A2 ◽  
Rabbit Aorta ◽  
Human Platelets ◽  
Appreciable Effect ◽  
Layer Chromatography ◽  
Aggregation Of Platelets ◽  
Platelet Functions

Studies on the effect of heparin on platelet functions have resulted in conflicting observations: heparin has been reported to cause aggregation of platelets, potentiate aggregation induced by various aggregating agents, or cause inhibition of aggregation. Using paritally purified heparin (beef lung or porcine mucosa) we observed that addition of heparin to citrated platelet rich plasma(C-PRP)potentiated the aggregation of platelets induced by ADP, epinephrine, or arachidonic acid. Presence of heparin in C-PRP results in complete inhibition of thrombin induced effects and partial inhibition of platelet aggregation induced by collagen. Presence of heparin in C-PRP also resulted in release of significantly higher concentrations of 14C-serotonin when platelets were challenged by appropriate aggregating agents. Those concentrations of heparin that resulted in potentiation of aggregation had no appreciable effect on c-AiMP or c-GMP levels of platelets. However, the presence of heparin results in a significant elevation of thromboxane A2 as determined by contraction of rabbit aorta or after conversion to thromboxane B2 by thin layer chromatography. These observations are of interest since increased production of thromboxane A2 in the presence of heparin may explain in part, the potentiation of platelet aggregation in vitro or thrombocytopenia observed frequently in patients receiving heparin intravenously Supported in part by grants HL22583 & 20679 from NHLBI of NIH.

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