Discrimination Between Prostglandin-Dependent And-Independent Functions Of Essential Fatty Acids In Arterial Throm- Bogenesis

1981 ◽  
Author(s):  
U M T Houtsmuller ◽  
G Hornstra ◽  
E Haddeman
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Linoleic Acid ◽  
Platelet Aggregation ◽  
Arterial Thrombosis ◽  
Thrombus Formation ◽  
Arterial Thrombus ◽  
Induced Aggregation

Arterial thrombus formation is reduced in essential fatty acid (EFA) deficiency. This goes together with an enhanced thrombin induced aggregation of platelets in vitro,whereas collagen-induced aggregation is definitely suppressed. A small amount of linoleic acid (18:2 (n-6)) is able to cure EFA-deficiency and to normalize arterial thrombogenesis. This latter effect may be due to either the structural function of this EFA or to its function as the ultimate dietary precursor of prostaglandins (PG). Columbinic acid, a stereo-isomer of γ-linolenic acid (18:3 (n-6)) was recently shown to possess all the structural functions of EFA, but not the PG-dependent ones. This fatty acid therefore presents a suitable tool to investigate the PG-dependence of arterial thrombogenesis and its underlying processes. We therefore compared the effect of small amounts of linoleic and columbinic acid (both as methylesters) on the water vapour release in vivo (which is a sensitive parameter for a non-PG dependent function of polyenoic fatty acids), arterial thrombosis tendency (time needed for the thrombotic obstruction of an aorta prosthesis) and platelet aggregation in vitro (aggregometry) induced by collagen and thrombin. In contrast to linoleic acid, columbinic acid did not normalize arterial thrombosis tendency and collagen induced platelet aggregation. Columbinic acid was equally effective as linoleic acid in the normalization of the water vapour release in vivo and of the thrombin-induced aggregation. We conclude that arterial thrombus formation and collagen- induced aggregation greatly depend on prostanoid formation, whereas thrombin-induced aggregation does not. The structural role of polyenoic fatty acids in thrombin-induced aggregation may provide a tool in the elucidation of factors determining the thrombin-sensitivity of blood platelets.

A Locally Administered Novel Heparin Complex Attenuates Collagen-Induced Platelet Activation and Thrombosis In Vivo,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3361-3361
Author(s):  
Riitta Lassila ◽  
Annukka Jouppila ◽  
Ulla M Marzec ◽  
Stephen R Hanson
Keyword(s):  
Blood Flow ◽  
Platelet Aggregation ◽  
Thrombus Formation ◽  
Ptfe Graft ◽  
Thrombin Time ◽  
Thrombosis Model ◽  
Baboon Model ◽  
Induced Aggregation

Abstract Abstract 3361 We have developed a semi-synthetic antithrombotic heparin complex, APL001, to mimic mast cell-derived natural heparin proteoglycans (HepPG). HepPG attenuate platelet-collagen interactions under blood flow by inhibiting VWF- and GPIIb/IIIa -mediated platelet aggregation. In addition, rat-derived HepPG arrest platelet thrombus growth on collagen surfaces or at vascular injury sites, both in vitro and in vivo (Lassila et al.ATVB 1997, Kauhanen et al. ATVB 2000, Olsson et al. Thromb Haemost 2002). Our objective was to study the inhibitory capacity of APL001 for preventing human platelet aggregation in vitro and acute thrombosis in a baboon model in vivo. The effects of unfractionated heparin (UFH) and APL001 were compared in relevant coagulation assays (APTT, PT, thrombin time, anti-FXa activity, fibrinogen, FVIII:C and VWF activity (VWF:RCo) and antigen). Additionally, agonist-induced (collagen, ristocetin and ADP) platelet aggregation in citrate or hirudin-anticoagulated whole blood (Multiplate®) (n=10 healthy subjects), and platelet function analysis (PFA100®) in citrated platelet rich plasma (PRP) were assessed. In a well-established baboon thrombosis model a collagen-coated PTFE graft (length 2 cm, lumen 4 mm) was placed in an arterio-venous shunt. Prior to blood contact the thrombogenic surface was treated for 10 min with UFH or APL001 (both at 4 mg/mL). Thrombus formation was initiated by exposing the surface to blood flow (100 mL/min, shear rate 265−1), and the deposition of 111-In-labeled platelets and of fibrin was quantified continuously over 1h. Fibrin thrombus accumulation was assessed from the incorporation of circulating 125-I-fibrinogen. In the heparin-relevant coagulation tests APL001 was comparable or 20–30% more potent than UFH while FVIII, fibrinogen and VWF variables remained unaltered. In contrast to UFH, APL001 (300 μg/mL) consistently inhibited collagen- and ristocetin-induced platelet aggregation, whereas UFH had only a modest effect in comparison with PBS control (Table). ADP-induced aggregation was unaffected. Comparable results were observed in the PRP aggregation assay. PFA100 testing also demonstrated inhibitory effects. In the in vivo thrombosis model (n=4) APL001 reduced platelet deposition on collagen (vs. the results with UFH) by 34% (p=0.01), while platelet accumulation in distal propagated thrombus was reduced by 61% (p=0.16). APL001-treated surfaces accumulated 45% less fibrin than the UFH-treated surfaces (p=0.008). In conclusion, when compared with UFH APL001 inhibited both collagen- and ristocetin-induced platelet aggregation in human blood, while anticoagulant properties were comparable. In the absence of systemic antithrombotic drugs, exposure of APL001 to a highly thrombogenic collagen surface arrested thrombus formation in an in vivo baboon model. This finding suggests that locally administered APL001 alone, due to its dual antiplatelet and anticoagulant effects, may limit the growth and size of thrombus and thereby prevent subsequent thrombo-occlusion.TableAnticoagulantInhibition-% of platelet aggregation ± SDConc. 300 μg/mLnColl (3.2 μg/mL)Ristocetin (0.77 mg/mL)ADP (6.4 μM)CitrateAPL0011033 ± 1543 ± 166 ± 24UFH1011 ± 1323 ± 153 ± 7p value0.0030.0100.700HirudinAPL0011032 ± 1043 ± 178 ± 10UFH108 ± 1116 ± 166 ± 9p value0.0000.0020.600 Disclosures: Lassila: Aplagon: Chief Scientific Advisor.

Abstract 33: Platelet 12-lipoxygenase is a Key Regulator of Platelet Reactivity and Thrombus Formation in vivo

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Reheman Adili ◽  
Katherine Mast ◽  
Theodore R Holman ◽  
Michael Holinstat
Keyword(s):  
Platelet Aggregation ◽  
Ex Vivo ◽  
Platelet Reactivity ◽  
Thrombus Formation ◽  
High Shear ◽  
Vessel Occlusion ◽  
12 Lipoxygenase ◽  
Induced Aggregation

Background: Platelet reactivity is required to maintain hemostasis, however high platelet reactivity leads to thrombus formation, myocardial infarction, and stroke. Platelet 12-lipoxygenase (12-LOX) has been demonstrated by our lab and others to regulate agonist-mediated platelet reactivity suggesting a role for 12-LOX in regulation of in vivo thrombosis. The ability to target 12-LOX in vivo has not been established to date. Therefore, we sought to determine if 12-LOX regulates platelet reactivity and thrombus formation in vivo using the selective 12-LOX inhibitor ML355 to determine whether platelet 12-LOX is an effective target for anti-platelet therapeutics. Methods: ML355 effects on human platelet function was assessed in vitro by platelet aggregometry, ex vivo by perfusion chamber, and in vivo by thrombus formation and vessel occlusion in small and large vessels in 12-LOX -/- , WT mice, and mice treated with ML355 via intravital microscopy using the FeCl 3 and laser injury models. Results: In in vitro platelet aggregation, ML355 dose-dependently inhibited agonist-induced aggregation. In ex vivo flow chamber assays, platelet adhesion and thrombus formation on collagen-coated surfaces at high shear was attenuated in both mouse and human whole blood after incubation with ML355. Further, platelet aggregation and thrombus growth in 12-LOX -/- mice were impaired in both laser and FeCl 3 -induced mesenteric, carotid artery and cremaster arteriole thrombosis models. Thrombi in 12-LOX -/- mice were unstable and frequently formed emboli, which resulted in impaired vessel occlusion or reopening. Additionally, thrombus formation and vessel occlusion was impaired in ML355 treated WT mice. Conclusions: The 12-LOX inhibitor ML355 inhibits platelet aggregation induced by a number of platelet agonists. Ex vivo high shear conditions in both mice and human was attenuated in the presence of ML355. Thrombus formation and vessel occlusion were impaired in mice deficient in 12-LOX. Finally, ML355 attenuates thrombus formation and prevents vessel occlusion in vivo . Our data strongly indicates 12-LOX is an important determinant of platelet reactivity and inhibition of platelet 12-LOX may represent a new target for anti-platelet therapeutics.

Comparison of the Effects of Two Diets Rich in Monounsaturated Fatty Acids Differing in their Linoleic/α-Linolenic Acid Ratio on Platelet Aggregation

1994 ◽  
Vol 71 (01) ◽  
pp. 073-077 ◽  
Author(s):  
Riitta Freese ◽  
Marja Mutanen ◽  
Liisa M Valsta ◽  
Irma Salminen
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Platelet Aggregation ◽  
Linolenic Acid ◽  
Sunflower Oil ◽  
Rapeseed Oil ◽  
Monounsaturated Fatty Acids ◽  
Acid Ratio ◽  
Induced Aggregation

SummaryThe effect of dietary linoleic/α-linolenic acid ratio on human platelet aggregation in vitro was investigated using low-erucic acid rapeseed oil and high-oleic acid sunflower oil as the major fat sources. In a cross-over study 20 healthy male subjects, average age 29 year (range 20–46 yr), followed experimental rapeseed oil (RO) and Trisun-sunflower oil (TSO) diets after their habitual diet for six weeks. Subjects were provided most of the fat containing foods but were allowed to eat other foods almost freely. Fatty acid compositions of the diets calculated from dietary records were as follows (saturated/monounsaturated/polyunsaturated fatty acids): RO diet 12.4/18.6/8.9% of total energy (en%) (linoleic/α-linolenic acid ratio 2.8) and TSO diet 11.8/17.8/8.3 en% (linoleic/α-linolenic acid ratio 28), respectively. Plasma cholesterol ester fatty acid composition proved compliance to the experimental diets. Platelet aggregations induced by ADP (1,2 and 3 μM) or thrombin (0.12, 0.15 and 0.18 NIH/ml) were significantly enhanced and collagen- (1.5, 2.5 and 5.0 μg/ml) induced aggregation tended to be enhanced after the TSO diet compared with the RO diet. After the TSO diet platelet aggregation was enhanced from the level of the habitual diets by one thrombin (0.18 NIH/ml), one collagen (1.5 μg/ml) and all three ADP concentrations. The diets had no effect on antithrombin III activity. Results show that platelet aggregation in vitro decreases as the ratio of linoleic acid to a-linolenic acid decreases in diets rich in monounsaturated fatty acids.

Anti-Human VWF Monoclonal Antibody SZ-123 Prevents Arterial Thrombus Formation by Inhibiting VWF–collagen and VWF-Platelet Interactions in Rhesus Monkeys

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 5194-5194
Author(s):  
Yiming Zhao ◽  
Changgeng Ruan
Keyword(s):  
Monoclonal Antibody ◽  
Platelet Aggregation ◽  
Bleeding Time ◽  
Conflicts Of Interest ◽  
Ex Vivo ◽  
Thrombus Formation ◽  
Significant Prolongation ◽  
Arterial Thrombus

Abstract Abstract 5194 Objective: To investigate the in vivo antithrombotic efficacy of an anti-VWF monoclonal antibody SZ-123, and its potential underlying mechanism. Methods and Results: Cyclic flow reductions (CFRs) were measured in the femoral artery of monkeys before and after intravenous administration of SZ-123. Ex vivo VWF binding to collagen, platelet aggregation, platelet count and template bleeding time were performed as measurements of antithrombotic activity. In addition, plasma VWF, SZ-123 levels, and VWF occupancy were measured by ELISA. Administration of 0. 1, 0. 3, and 0. 6 mg/kg SZ-123 resulted in 45. 3%, 78. 2%, and 100% reduction in CFRs, respectively. When 0. 3 and 0. 6 mg/kg SZ-123 were administrated, 100% of VWF was occupied by the antibody. Moreover, 100% ex vivo inhibition of VWF-collagen binding and 60–95% inhibition of platelet aggregation were observed from 15 min to 1h. None of the doses resulted in significant prolongation of bleeding time. In vitro experiment also revealed that SZ-123 not only blocks collagen-VWF A3 interaction but also inhibits indirectly VWF A1 binding to GPIba induced by ristocetin. Conclusions: SZ-123 prevents in vivo arterial thrombus formation under high shear conditions by inhibiting VWF A3–collagen and VWF A1-platelet interactions and does not prolong bleeding time. Disclosures: No relevant conflicts of interest to declare.

Abstract 450: Phosphorylation Of Platelet αIIbβ3 Is Crucial For Arterial Thrombosis In Vivo And Microparticle Generation

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Manojkumar Valiyaveettil ◽  
Weiyi Feng ◽  
Ganapati Mahabaleshwar ◽  
David Phillips ◽  
Tatiana Byzova ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Tyrosine Phosphorylation ◽  
Arterial Thrombosis ◽  
Thrombus Formation ◽  
Annexin V ◽  
Vessel Occlusion ◽  
Occlusion Time ◽  
Fibrinogen Receptor

Functional activity of platelet fibrinogen receptor αIIbβ3 is crucial for hemostasis and thrombosis. The process of αIIbβ3 activation in platelet aggregation is tightly regulated. It has been previously shown that β3 subunit of the complex undergo tyrosine phosphorylation, which, in turn, is believed to control recruitment of several intracellular adaptors. Mutations of Tyr747/ Tyr759 within the cytoplasmic domain of αIIbβ3 (DiYF substitution) were found to result in reversible platelet aggregation. To assess whether αIIbβ3 tyrosine phosphorylation is critical for arterial thrombosis, we utilized intravital microscopy to monitor thrombus formation in vivo in WT and DiYF mice. Compared to WT, DiYF mice exhibited delayed platelet adhesion and reduced rate of thrombus formation at the initial stages of thrombosis. Likewise, isolated DiYF platelets exhibited reduced adhesion to collagen under in vitro sheer conditions compared to WT. The progression phase of thrombosis in vivo was similar in WT and DiYF mice. The most dramatic difference was observed at the final phase of thrombus formation since it took 3-times longer for blood vessels in DiYF mice to occlude compared to WT. To specifically address the role if β3 phosphorylation in platelet αIIbβ3 vs αvβ3 on leukocytes and vascular cells, we transfused labeled WT and DiYF platelets into irradiated WT mice with low blood cells and platelet counts. It was found that transfusion of DiYF but not WT platelets resulted in reversal of the thrombotic phenotype and significantly prolonged blood vessel occlusion time in vivo. Similar differences were observed in tail bleeding test. Importantly, we have found that the lack of β3 phosphorylation impaired an ability of platelets to generate microparticles in response to activation, an event believed to be critical for the final stages of thrombosis. When stimulated with thrombin and PMA, DiYF platelets shed ~50% less Annexin V-positive microparticles as compared to WT platelets. Thus, β3 tyrosine phosphorylation of αIIbβ3 in platelets is crucial for the microparticles generation by activated platelets and the overall process of arterial thrombosis in vivo.

Platelet Aggregation in Finnish Men and Its Relation to Fatty Acids in Platelets, Plasma and Adipose Tissue

1985 ◽  
Vol 54 (03) ◽  
pp. 563-569 ◽  
Author(s):  
M K Salo ◽  
E Vartiainen ◽  
P Puska ◽  
T Nikkari
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Platelet Aggregation ◽  
Acid Composition ◽  
Saturated Fatty Acids ◽  
Free Living ◽  
Ω3 Fatty Acids ◽  
Induced Aggregation

SummaryPlatelet aggregation and its relation to fatty acid composition of platelets, plasma and adipose tissue was determined in 196 randomly selected, free-living, 40-49-year-old men in two regions of Finland (east and southwest) with a nearly twofold difference in the IHD rate.There were no significant east-southwest differences in platelet aggregation induced with ADP, thrombin or epinephrine. ADP-induced platelet secondary aggregation showed significant negative associations with all C20-C22 ω3-fatty acids in platelets (r = -0.26 - -0.40) and with the platelet 20: 5ω3/20: 4ω 6 and ω3/ ω6 ratios, but significant positive correlations with the contents of 18:2 in adipose tissue (r = 0.20) and plasma triglycerides (TG) (r = 0.29). Epinephrine-induced aggregation correlated negatively with 20: 5ω 3 in plasma cholesteryl esters (CE) (r = -0.23) and TG (r = -0.29), and positively with the total percentage of saturated fatty acids in platelets (r = 0.33), but had no significant correlations with any of the ω6-fatty acids. Thrombin-induced aggregation correlated negatively with the ω3/6ω ratio in adipose tissue (r = -0.25) and the 20: 3ω6/20: 4ω 6 ratio in plasma CE (r = -0.27) and free fatty acids (FFA) (r = -0.23), and positively with adipose tissue 18:2 (r = 0.23) and 20:4ω6 (r = 0.22) in plasma phospholipids (PL).The percentages of prostanoid precursors in platelet lipids, i. e. 20: 3ω 6, 20: 4ω 6 and 20 :5ω 3, correlated best with the same fatty acids in plasma CE (r = 0.32 - 0.77) and PL (r = 0.28 - 0.74). Platelet 20: 5ω 3 had highly significant negative correlations with the percentage of 18:2 in adipose tissue and all plasma lipid fractions (r = -0.35 - -0.44).These results suggest that, among a free-living population, relatively small changes in the fatty acid composition of plasma and platelets may be reflected in significant differences in platelet aggregation, and that an increase in linoleate-rich vegetable fat in the diet may not affect platelet function favourably unless it is accompanied by an adequate supply of ω3 fatty acids.

scholarly journals ROLE OF NITRIC OXIDE (NO) IN CAPSAICIN MEDIATED ANTI-PLATELET ACTIVITY IN IN VITRO, IN VIVO, EX-VIVO MODEL OF PLATELET AGGREGATION ASSAY AND ARTERIAL THROMBOSIS IN RAT: POTENTIAL THERAPEUTIC TARGET?

2018 ◽  
Vol 10 (4) ◽  
pp. 44
Author(s):  
Mihir K Patel ◽  
Kiranj K. Chaudagar ◽  
Anita A. Mehta
Keyword(s):  
Platelet Aggregation ◽  
Arterial Thrombosis ◽  
Ex Vivo ◽  
Platelet Activity ◽  
Aggregation Assay ◽  
Thrombosis Model ◽  
Platelet Aggregation Assay

Objective: Although recent advances in the treatment of congestive heart disease, mortality among patients’ remains a questionable remark. Therefore, we evaluated the role of capsaicin on in vitro and ex vivo platelet aggregation induced by Adenosine Di-Phosphate (ADP) as well as in in vivo thrombosis models and role of NO, KATP was also identified in the capsaicin-induced anti-platelet animal model as well as in vivo model of arterial thrombosis.Methods: According to body weight wistar rats were divided into five groups. Group I and Group II was treated with saline and capsaicin (3 mg/kg, i. v), while animals from Group III were treated with N(ω)-nitro-L-arginine methyl ester (L-NAME) (30 mg/kg, i. v) 30 min before administration of capsaicin (3 mg/kg, i. v). Group IV animals were treated with glibenclamide (10 mg/kg,i. v) 30 min before administration of capsaicin (3 mg/kg, i. v). Group V was considered as a positive control and administered clopidogrel (30 mg/kg, p. o). Animals were subjected for in vitro, ex-vivo platelet aggregation assay. ADP (30µM) was utilized as an aggregating agent in these experiments. After these assays; animals of each group were subjected for subaqueous tail bleeding time in a rat model and FeCl3-induced arterial thrombosis model in rats.Results: In ADP-induced in vitro platelet aggregation, a significant reduction in % platelet aggregation was observed at 50µM (64.35±4.641) and 100µM (52.72±4.192) concentration of capsaicin as compared to vehicle control (85.82±3.716). Capsaicin (3 mg/kg, i. v) also showed a significant reduction (49.53±4.075) in ex-vivo ADP-induced platelet aggregation as compared to vehicle control (89.38±2.057). In FeCl3 induced arterial thrombosis model, Capsaicin (3 mg/kg, i. v) exhibited an increase in time to occlusion in this rodent model and presence of the L-NAME and glibenclamide had inhibited the activity of capsaicin.Conclusion: In our study, capsaicin (50 µM, 100µM) exhibited potent anti-platelet activity in ADP-induced platelet aggregation, similarly capsaicin exhibited significant anti-platelet action in the ex-vivo study. Moreover, the presence of L-NAME and glibenclamide inhibited the anti-thrombotic and anti-platelet action of capsaicin. Therefore, it was concluded that NO and KATP may be involved in the anti-thrombotic action of capsaicin.

scholarly journals Studies investigating platelet aggregation and release initiated by sera from patients with thrombotic thrombocytopenic purpura

Blood ◽  
1987 ◽  
Vol 69 (3) ◽  
pp. 924-928 ◽  
Author(s):  
JG Kelton ◽  
JC Moore ◽  
WG Murphy
Keyword(s):  
Platelet Aggregation ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Disease Process ◽  
The Other ◽  
Platelet Glycoprotein ◽  
Glycoprotein Ib ◽  
Thrombocytopenic Purpura ◽  
Induced Aggregation

Many patients with thrombotic thrombocytopenic purpura (TTP) have a platelet aggregating factor in their serum that may be pathologically linked with the disease process. To help characterize the type of platelet aggregation and platelet release induced by the sera from seven TTP patients, we measured the ability of a variety of inhibitors of platelet function as well as the ability of monoclonal antibodies (MoAbs) against platelet glycoproteins to inhibit TTP sera-induced platelet aggregation and release. These results were compared with the ability of the same inhibitors to block platelet aggregation induced by ristocetin, collagen, ADP, thrombin, and IgG-immune complexes. Monoclonal antibody directed against platelet glycoprotein Ib totally inhibited ristocetin-induced aggregation and release but had no effect on aggregation and release induced by the TTP sera or by any of the other platelet agonists. However, the MoAb against glycoproteins IIb/IIIa inhibited aggregation and release caused by TTP sera as well as by collagen, thrombin, and ADP but had no effect on aggregation and release induced by ristocetin. The aggregating activity could be abolished by heparin but not by the serine protease inhibitor PMSF (1 mmol/L). And although monomeric human IgG and purified Fc fragments of IgG inhibited IgG-immune complex-induced aggregation and release, they had no effect on TTP sera-induced aggregation and release nor on aggregation and release induced by any of the other agonists. Consistent with these in vitro studies showing no effect of IgG were the in vivo observations that intravenous (IV) IgG was without effect when administered to three patients with TTP. This study indicates that although a von Willebrand factor (vWF)-rich preparation of cryoprecipitate enhances the in vitro platelet aggregation and release caused by sera from the seven TTP patients we studied, the pathway of aggregation and release is not via platelet glycoprotein Ib. Also the aggregating factor of TTP sera is not neutralized in vitro or in vivo by IgG.

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