Comparisons of Biochemical and Pharmacological Properties of Prostacyclins with Modified ω-Side Chain

1979 ◽  
Author(s):  
K. U. Weithmann ◽  
W. Bartmann ◽  
G. Beck ◽  
U. Lerch ◽  
E. Konz ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Systemic Blood Pressure ◽  
Side Chain ◽  
Adenylate Cyclase System ◽  
Dependent Manner ◽  
High Biological Activity ◽  
Structure Activity ◽  
Dose Dependent

PGI2-analogs in which the n-pentyl moiety in position 15 was replaced by several residues, were subjected to structure-activity studies. Some of the modified PGI2’s showed remarkable potency in regard to antiplatelet and vasodilator actions. in order to evaluate these potencies the inhibition of arachidonic acid induced platelet aggregation in human platelet rich plasma, relaxation of bovine coronary artery (BCA) and systemic blood pressure (BP) in the anesthetized rat were determined. Platelet aggregation was inhibited by PGI2 with an IC50 approx. 3-10-9M, BP was decreased in a dose dependent manner with an ED25, of 0.23 ug/kg i.v. and a marked relaxation of BCA was observed. Similar results were obtained with PGI2-methylester. Substitution of the n-pentyl moiety by cyclohexyl, 3-furyl-2-ethyl or 3-thienyl-oxymethyl resulted in PGI2- and PGI2-methyl-ester-analogs with high biological activity, whereas substitution by T6,16-dimethyl-18-oxa-alkyl or phenoxymethyl caused a loss of activity in the models used. The potency of the prostacyclins in the platelet model seem to depend upon their ability to elevate the platelet cyclo-AMP level. Thus the antiplatelet potency of modified PGI2’s may reflect their ability to affect the adenylate cyclase system.

Comparisons of Biochemical and Pharmacological Properties of Prostacyclins with Modified ω-Side Chain

1979 ◽  
Author(s):  
K.U. Weithmann ◽  
W. Bartmann ◽  
G. Beck ◽  
U. Lerch ◽  
E. Konz ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Systemic Blood Pressure ◽  
Side Chain ◽  
Adenylate Cyclase System ◽  
Dependent Manner ◽  
High Biological Activity ◽  
Structure Activity ◽  
Dose Dependent

PGI2-analogs in which the n-pentyl moiety in position IS was replaced by several residues, were subjected to structure-activity studies. Some of the modified PGI2’s showed remarkable potency in regard to antiplatelet and vasodilator actions. In order to evaluate these potencies the inhibition of arachidonic acid induced platelet aggregation in human platelet rich plasma, relaxation of bovine coronary artery (BCA) and systemic blood pressure (BP) in the anesthetized rat were determined. Platelet aggregation was inhibited by PGI2, with an IC50 approx. 3.10-9, BP was decreased in a dose dependent manner with an ED25 of 0.23 ug/kg i.v. and a marked relaxation of BCA was observed. Similar results were obtained with PGK-methylester. Substitution of the n-pentyl moiety by cyclohexyl, 3-furyl-2-ethyl or 3-thienyl-oxymethyl resulted in PGI2, and PGK2-methyl-ester-analogs with high biological activity, whereas substitution by 16, 16-dimethyl-18-oxa-alkyl or phcnoxymethyl caused a loss of activity in the models used. The potency of the prostacyclins in the platelet model seem to depend upon their ability to elevate the platelet cyclo-AMP level. Thus the antiplatelet potency of modified PGI2’s may reflect their ability to affect the adenylate cyclase system.

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.

scholarly journals Studies on the Biological Effects of Ozone: 10. Release of Factors from Ozonated Human Platelets

1999 ◽  
Vol 8 (4-5) ◽  
pp. 205-209 ◽  
Author(s):  
G. Valacchi ◽  
Velio Bocci
Keyword(s):  
Platelet Aggregation ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Platelet Rich Plasma ◽  
Biological Effects ◽  
Transforming Growth Factor Β1 ◽  
Human Platelets ◽  
Dependent Manner ◽  
Dose Dependent ◽  
Tgf Β1

In a previous work we have shown that heparin, in the presence of ozone (O3), promotes a dose-dependent platelet aggregation, while after Ca2+chelation with citrate, platelet aggregation is almost negligible. These results led us to think that aggregation may enhance the release of platelet components. We have here shown that indeed significantly higher amount of platelet-derived growth factor (PDGF), transforming growth factor β1 (TGF-β1) and interleukin-8(IL-8) are released in a dose-dependent manner after ozonation of heparinised platelet-rich plasma samples. These findings may explain the enhanced healing of torpid ulcers in patients with chronic limbischemia treated with O3autohaemoteraphy (O3-AHT).

scholarly journals Resolvin E1, an EPA-derived mediator in whole blood, selectively counterregulates leukocytes and platelets

Blood ◽  
2008 ◽  
Vol 112 (3) ◽  
pp. 848-855 ◽  
Author(s):  
Maria Dona ◽  
Gabrielle Fredman ◽  
Jan M. Schwab ◽  
Nan Chiang ◽  
Makoto Arita ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Lipid Mediator ◽  
Dependent Manner ◽  
Omega 3 ◽  
Concentration Dependent Manner ◽  
Chemokine Production ◽  
Thromboxane Receptor

Abstract Resolvin E1 (RvE1) is an omega-3 eicosapentaenoic acid (EPA)–derived lipid mediator generated during resolution of inflammation and in human vasculature via leukocyte-endothelial cell interactions. RvE1 possesses anti-inflammatory and proresolving actions. Here, we report that RvE1 in human whole blood rapidly regulates leukocyte expression of adhesion molecules. RvE1 in the 10- to 100-nM range stimulated L-selectin shedding, while reducing CD18 expression in both neutrophils and monocytes. When added to whole blood, RvE1 did not stimulate reactive oxygen species by either neutrophils or monocytes, nor did it directly stimulate cytokine/chemokine production in heparinized blood. Intravital microscopy (IVM) demonstrated that RvE1 rapidly reduced leukocyte rolling (∼ 40%) in venules of mice. In human platelet-rich plasma (PRP), RvE1 selectively blocked both ADP-stimulated and thromboxane receptor agonist U46619-stimulated platelet aggregation in a concentration-dependent manner. In contrast, Δ6,14-trans-RvE1 isomer was inactive. RvE1 did not block collagen-stimulated aggregation, and regulation of ADP-induced platelet aggregation was not further enhanced with aspirin treatment. These results indicate RvE1 is a potent modulator of leukocytes as well as selective platelet responses in blood and PRP, respectively. Moreover, the results demonstrate novel agonist-specific antiplatelet actions of RvE1 that are potent and may underlie some of the beneficial actions of EPA in humans.

Abstract 351: Plasma Phospholipid Transfer Protein Promotes Platelet Aggregation

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Xiao-Min Zhao ◽  
Yun Wang ◽  
Shu-Cun Qin ◽  
Xian Jiang
Keyword(s):  
Plasma Membrane ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
Phospholipid Transfer Protein ◽  
Dependent Manner ◽  
Exterior Surface ◽  
Transfer Protein ◽  
Fibrinogen Binding ◽  
Phospholipid Transfer ◽  
Dose Dependent

Hypothesis: Phospholipid transfer protein (PLTP) has a direct effect on platelet aggregation, since PLTP knockout mice have longer bleeding time. Methods and Results: Platelets from humans or mice were prepared as were mouse platelet-rich plasma and human recombinant PLTP (rPLTP). In mice, we assessed ADP- and collagen-induced platelet aggregation, phosphatidylserine (PS) externalization, and photothrombosis-induced cerebral infarction. We found that human platelets produce PLTP. Platelet aggregation increased upon PLTP overexpression whereas it decreased with PLTP deficiency in a gene dose-dependent manner. Human rPLTP increased mouse or human platelet aggregation in a dose-dependent manner. PS externalization provides a water/lipid surface for the interaction of coagulation factors, which accelerates thrombosis. Compared with wild type controls, platelets from PLTP transgenic mice had significantly greater amounts of PS on the exterior surface of the plasma membrane, whereas platelets from PLTP-deficient mice had significantly less on the surface, thus influencing fibrinogen binding. Moreover, rPLTP together with ADP significantly increased PS exposure on the plasma membrane of PLTP-deficient platelets, thereby increasing fibrinogen binding. Importantly, PLTP overexpression significantly accelerated the incidence of photothrombosis-induced infarction, whereas PLTP deficiency reduced the incidence. Conclusions: PLTP promotes PS externalization at the plasma membrane of platelets and accelerates ADP- or collagen-induced platelet aggregation. Thus, PLTP is involved in hypercoagulation. Therefore, PLTP inhibition could be a novel approach for countering thrombosis.

Interaction between ATP and catecholamines in stimulation of platelet aggregation

2003 ◽  
Vol 284 (2) ◽  
pp. H619-H625 ◽  
Author(s):  
Alex V. Birk ◽  
Endri Leno ◽  
Hugh D. Robertson ◽  
Victoria M. Bolotina ◽  
Hazel H. Szeto
Keyword(s):  
Platelet Aggregation ◽  
Human Platelet ◽  
Platelet Reactivity ◽  
Platelet Rich Plasma ◽  
Endothelial Damage ◽  
Clinical Implications ◽  
Induce Platelet Aggregation ◽  
Intracellular Ca ◽  
Dose Dependent ◽  
Stimulation Of

Platelets, on activation by endothelial damage, release ADP, ATP, serotonin, epinephrine, and norepinephrine. Although ATP is known to augment the action of norepinephrine in cardiovascular and endocrine systems, the possible interaction between ATP and catecholamines in regulation of platelet reactivity has not been reported. The addition of ATP (1–5 μM) to human platelet-rich plasma did not induce platelet aggregation; however, it selectively augmented the aggregatory response to norepinephrine and epinephrine, but not to serotonin. This potentiating action of ATP was dose dependent and was not due to contamination by, or hydrolysis to, ADP. The action of ATP was blocked by 10 μM of adenosine 3′-phosphate 5′-phosphosulfate, a selective P2Y1receptor antagonist. ATP alone did not cause release of intracellular Ca2+, but produced a significant Ca2+response in the presence of norepinephrine. In contrast, the P2X1receptor agonists P1,P6-diadenosine-5′ hexophosphate and α,β-methylene-ATP had no effect on norepinephrine-induced platelet aggregation even when added at 100 μM. This synergistic interaction between ATP and norepinephrine in stimulating platelet aggregation may have significant clinical implications and suggests a prothrombotic role for ATP in stress.

scholarly journals The effect of chlorin e6 drug on platelet aggregation activity

2019 ◽  
Vol 8 (3) ◽  
pp. 4-10 ◽  
Author(s):  
N. N. Petrishchev ◽  
M. A. Galkin ◽  
T. G. Grishacheva ◽  
I. N. Dementjeva ◽  
S. G. Chefu
Keyword(s):  
Platelet Aggregation ◽  
Laser Irradiation ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Dependent Manner ◽  
Functional Changes ◽  
Aggregation Activity ◽  
Dose Dependent

The goal of the study is to evaluate the effect of Radachlorin (OOO “RADA-PHARMA”, Russia) (RC) on platelet aggregation in ex vivo and in vivo experiments. The experiments were conducted on male Wistar rats. Platelet aggregation activity was determined in platelet-rich plasma (PRP) using a turbidimetric method and the aggregation inducer was ADP at a final concentration of 1.25 μM. PRP samples containing RC were irradiated with ALOD-Granat laser device (OOO “Alkom Medika”, Russia) at 662 nm wavelength with 0.05 W/cm2 power density. After a 5-minute incubation of PRP with RC in the dark, dose-dependent inhibition of platelet aggregation was observed. Laser irradiation (12.5 J/cm2 and, especially, 25 J/cm2) increased the inhibitory effect of RC. 3 hours after intravenous administration of RC, the rate and intensity of platelets aggregation did not change, while disaggregation slowed down significantly. Irradiation at a dose of 5 J/cm2 did not affect the platelets aggregation kinetics, and disaggregation slowed down even more at 10 J/cm2, and at 20 J/cm2 the rate and intensity of platelets aggregation decreased, and no disaggregation occurred.In vitro, RC inhibited the ADP-induced platelet aggregation in rats in a dose-dependent manner; after laser irradiation, this effect was enhanced significantly. The effect of RC on circulating platelets leads to a change in their functional state, which manifests in slowing down the disaggregation after exposure to ADP. After laser irradiation (10 J/cm2 and, especially, 20 J/cm2), the severity of the functional changes increases. The role of decreasing the disaggregation activity of platelets in the mechanism of vascular thrombosis in the affected area of photodynamic therapy (PDT) is discussed.

scholarly journals Liposomal form of lipoic acid: preparation and determination of antiplatelet and antioxidant activity

2016 ◽  
Vol 62 (5) ◽  
pp. 577-583 ◽  
Author(s):  
V.A. Shchelkonogov ◽  
G.M. Sorokoumova ◽  
O.A. Baranova ◽  
A.V. Chekanov ◽  
A.V. Klochkova ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Arachidonic Acid ◽  
Platelet Aggregation ◽  
Lipoic Acid ◽  
Platelet Rich Plasma ◽  
Antioxidant Properties ◽  
Dependent Manner ◽  
Liposomal Form ◽  
Dose Dependent

Optimal conditions for obtaining phosphatidylholine (PC) liposomes with lipoic acid (LA) are chosen that lead to the formation of nanoparticles with a size of 175¸284 nm with efficiency (extent) of inclusion of LA in liposomes equal 85% and characterized by a slow release of substance from the nanoparticles. The effect of “empty” liposomes and liposomal form of LA on platelet aggregation induced by arachidonic acid (AA) is established. It is found that liposomes with LА inhibit platelet aggregation, caused by AА, to 80%. In addition, it is shown that “empty” liposomes slightly (to 30%) suppress platelet aggregation, caused by AА. The amount of TBA-sensitive products in samples of platelet-rich plasma (PRP) incubated with liposomal LA is determined. It is shown that LA in the composition of liposomes retains its antioxidant properties, and the amount of products of lipid peroxidation in platelet-rich plasma decreases in a dose-dependent manner when arachidonic acid is used as an inductor of platelet aggregation. It is assumed that the antiplatelet action of the liposomal form of LА is induced by inhibition of the initiation of lipid peroxidation products caused by exogenous inducer AА. It is supposed that, after additional research, the liposomal form of LA can be considered as a new drug in complex treatment of cerebral ischemia.

The Effect of a Medicinal Chinese Herb on Platelet Function

1982 ◽  
Vol 48 (03) ◽  
pp. 301-306 ◽  
Author(s):  
Z Wang ◽  
J M Roberts ◽  
P G Grant ◽  
R W Colman ◽  
A D Schreiber
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Platelet Rich Plasma ◽  
Chinese Herb ◽  
Serotonin Release ◽  
Dependent Manner ◽  
Heat Stable ◽  
Artery Disease ◽  
Dose Dependent

SummaryWe investigated the effect of the Chinese herb Injectio Salvia Miltiorrhizae (ISM) on human platelet function in vitro. ISM inhibited platelet aggregation and serotonin release induced by either ADP or epinephrine in a dose dependent manner. This effect of ISM was observed with both gel-filtered platelets (ID50 = 8–30 μg ISM/ml gel-filtered platelets) and platelets in plasma (ID50 = 400–900 μg ISM/ml of platelet-rich plasma). The active molecule(s) in ISM was heat stable, resistant to acid, base and proteolysis and fractionated on Sephadex 6-25 at MW ~ 280. ISM did not interact with the platelet α-adrenergic receptor, but increased cAMP in intact platelets. The results are consistent with the concept that ISM inhibition of platelet aggregation and release is mediated by an increase in platelet cAMP. The exact mechanism whereby ISM increases platelet cAMP appears to be that of inhibition of cyclic AMP phosphodiesterase. The effect of ISM on platelet function is one mechanism which might explain the therapeutic effect of ISM in experimental and clinical coronary artery disease.

scholarly journals 3’5’-Adenosine Diphosphate (3′5′ADP):A Physiological Inhibitor of Platelet Aggregation and Platelet Release Reaction

1977 ◽  
Author(s):  
K. Subbarao ◽  
K. Jaya
Keyword(s):  
Platelet Aggregation ◽  
Coenzyme A ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Serotonin Release ◽  
Dependent Manner ◽  
Release Reaction ◽  
Inhibition Of Platelet Aggregation ◽  
Vitro Effect ◽  
Aggregation Of Platelets

Certain analogues of adenosine have been shown to inhibit ADP-induced platelet aggregation. We therefore studied the in vitro effect of 3′5′ADP and coenzyme A on human platelet aggregation and [14C]-serotonin release reaction induced by the addition of ADP, thrombin, collagen and epinephrine to human platelet rich plasma (PRP). It was found that coenzyme A Li3·2H2O at a concentration of 0.12 mM strongly inhibited ADP-induced platelet aggregation of PRP but did not show similar effect on the aggregation of platelets induced by other aggregating agents. The 3′5′ADP which is a part of coenzyme A structure, on the other hand, inhibited both ADP and thrombin induced platelet aggregation. The extent of inhibition of platelet aggregation by coenzyme A and 3′5′ADP was found to depend upon the concentration of the inhibitor and the incubation time. Whereas 3′5′ADP Li2·3H2O at a concentration of 10 μM produced about 70% inhibition of ADP-induced platelet aggregation of human PRP, total inhibition of thrombin induced platelet aggregation was observed when platelets were incubated with 60 μM of 3′5′ADP. The 3′5′ADP also inhibited the [14C]-adeonsine uptake by platelets in a concentration dependent manner. The inhibitory potency of 3′5′ADP on platelet aggregation was found to be 10-fold higher than that of N6-2′-0-dibutyryl-cyclic 3′5′-adenosine monophosphate. The inhibition of platelet aggregation by coenzyme A and 3′5′ADP was always accompanied by the inhibition of [14C]-serotonin release reaction. If coenzyme A and 3′5′ADP are indeed physiological inhibitors of platelet aggregation, then aggregation of platelets should depend on metabolic events that regulate the concentration of these agents in blood.

Sign in / Sign up

Export Citation Format

Share Document