Inhibitory Effect of β-Elemene Emulsion on Platelet Aggregation and its Mechanism

为阐明β榄香烯的抗血小板作用，本文分别采用比浊法和放免法测定大鼠连续ｉｐ７ｄβ榄香烯乳６．２５～１２．５ｍｇ·ｋｇ－１·ｄ－１后对血小板聚集、血浆ｋｅｔｏＰＧＦ１α和ＴＸＢ２水平的影响。结果表明，本品分别使凝血酶、花生四烯酸和ＡＤＰ诱导血小板最大聚集率下降３８．３％～４２．６％，１４．７％～１９．１％和７．２％～１０．８％，血浆ＴＸＢ２从８８ｎｇ·Ｌ－１下降至７２ｎｇ·Ｌ－１，ｋｅｔｏＰＧＦ１α从１７．５ｎｇ·Ｌ－１增加至２０．９ｎｇ·Ｌ－１。提示ＴＸＢ２降低和ｋｅｔｏＰＧＦ１α值增加是其抑制血小板聚集的作用机制之一。

EFFECTS OF NIMODIPINE ON PLATELET AGGREGATION AND THE ACTIVITY OF ENZYMES IN ARACHIDONIC ACID METABOLISM

The effects of nimodipine on platelet aggregation and arachidonic acid(AA)metabolism were studied in order to explore its effect on patients with thrombosis or cardiovas- cular disease.The results indicate that nimodipine(50-350μmol/L)significantly inhibits platelet aggregation induced by ADP,AA,and ionophore A23187 in a dose dependent manner.The inhibitory effects induced by ionophore A23187 could be partially antagonized by calcium(1 mmol/L).When the substrate was AA and the enzyme was supplied by pig lung microsomes,nimodipine(50-400μmol/L)significantly reduced the generation of TXB_2 and 6-keto-PGF_(1a) in parallel.When the substrate was prostaglandin endoperoxide, however,the levels of TXB_2 and 6-keto-PGF_(1a)were not significantly altered in the same concentration range.The results suggest that nimodipine is a cyclooxygenase inhibitor,and its ability to inhibit platelet aggregation is related to its calcium blocking effect.

Inhibitory effects and mechanisms of high molecular-weight phlorotannins from Sargassum thunbergii on ADP-induced platelet aggregation

We evaluated the effects of high molecular-weight phlorotannins from Sargassum thunbergii(STP) on ADP-induced platelet aggregation and arachidonic acid(AA) metabolism in New Zealand white rabbits and Wistar rats.The inhibition of STP on platelet aggregation was investigated using a turbidimetric method,and the levels of the terminal products of AA metabolism were measured using the corresponding kits for maleic dialdehyde(MDA),thromboxane B2(TXB2) and 6-keto-prostaglandin F1α(6-keto-PGF1α) by colorimetry and radioimmunoassay,as appropriate.We found that STP could inhibit ADP-induced platelet aggregation,and the inhibitory ratio was 91.50% at the STP concentration of 4.0 mg/mL.Furthermore,STP markedly affected AA metabolism by decreasing the synthesis of MDA(P<0.01) and increasing the synthesis of 6-keto-PGF1α,thus changing the plasma TXB2/6-keto-PGF1α balance when the platelets were activated(P<0.01).Therefore,STP altered AA metabolism and these findings partly revealed the molecular mechanism by which STP inhibits ADP-induced platelet aggregation.

Synthesis of Novel Ligustrazine Derivatives as Potential Platelet Aggregation Inhibitors

A series of novel ligustrazine derivatives were synthesized. These compounds have not been reported in literature, and their chemical structures were confirmed by IR, ^1H NMR and ESI-MS. The preliminary antiplatelet aggregation screening results demonstrated that the compounds 7a, 7b and 7c showed higher potency than ligustrazine.

A practical synthesis of sarpogrelate hydrochloride and in vitro platelet aggregation inhibitory activities of its analogues

A convenient approach for the preparation of sarpogrelate hydrochloride was developed.Two series of sarpogrelate hydrochloride analogues were designed and synthesized in order to improve their platelet aggregation inhibitory activities, biological tests suggested that these compounds have platelet aggregation inhibitory activities to some extent.

Platelet aggregation responses in type 2 diabetic patients

Diabetes mellitus (DM) is associated with platelet dysfunction. In diabetic patients, alterations in platelet functions, especially increased platelet agregation, have been suggested to cause increasing in cardiovascular morbidity and mortality or in accelaretion of athersclerotic process. In this study, we aimed to investigate the platelet aggregation response alterations and the effects of DM duration, HbA1c, treatment options among the patients with Type 2 DM. Fortyfive patients (case group;21 male, 24 female) with Type 2 DM and forty-eight healthy individuals (control group;22 male, 26 female) were included in this study. Platelet aggregation was determinated with Chorono-log 500 (USA) named device by using Chorono-log/ADP, Chorono-log/ collagen and Chorono-log/epinephrine kits. ADP-induced platelet aggregation was significantly higher in the case group compared with control group (p 【0.05). Epinephrine induced platelet aggregation were significant in negatively correlation with the diabetes duration (P 【0.05). Platelet aggregation responses did not differ according to their treatment type (sulphonylurea or insulin) was statistically insignificiant among the case groups (p 】0.05). In conclusion, our findings supported that type 2 diabetes may interfere with platelet functions without any relationship age, gender, the treatment types and the regulation levels. These findings supports that existence potential new factors or mechanism affecting platelet agregation. The subject requires more detailed studies in the future.

Effects of procainamide on adenosine diphosphate-induced platelet aggregation and thromboxane B_2 production in rabbits in vitro

Turbidimetry and radioimmunoassay were used to study the effects of procainamide (PA ) onadenosine diphosphate (ADP)-induced rabbit platelet aggregation and thromboxane B2 (TXB2) production invitro. PA 8. 5--544. 0 μmol L-1 inhibited ADP-induced platelet aggregation and TXB2 production, and theinhibition rates were 26. 7% -- 66. 7 % and 21. 4 % -- 70. 1 %, respectively. There was positive correlation between PA concentration and its efficiency in inhibiting the platelet aggregation and TXB2 production, and alsobetween the inhibition rates of platelet aggregation and that of TXB2 production. The three linear equationsand main parameters were The results indicate that PA could significantly inhibit ADP--induced platelet aggregation and TXB2 production in rabbits.

Hawanoids A–E, unprecedented diterpenoids with PAF-induced platelet aggregation inhibitory activities from the deep-sea-derived fungus Paraconiothyrium hawaiiense

Hawanoids A–E(1–5), five highly cyclized diterpenoids were isolated from the deep-sea-derived fungus Paraconiothyrium hawaiiense FS482. Compounds 1 and 2 possessed an unprecedented tetracyclo[6.6.2.0^(2,7).0^(11,15)]cetane carbon skeleton while 3 and 4 possessed an unusual 11,14-macrocyclic ether moiety in phomactin family. Their structures including the stereo-chemistry were determined through spectroscopic analysis, X-ray diffractions and computational calculations. The plausible biosynthetic pathway was proposed based on the predicted biosynthetic gene cluster. All of the isolated compounds exhibited inhibitory activities against PAF-induced platelet aggregation. The molecular docking study was carried out understand the interaction between the PAF receptor and hawanoids with different skeletons.

Effect of resveratrol on platelet aggregation in vivo and in vitro

OBJECTIVE: Low or moderate consumption of red wine has a greater benefit than the consumption of other beverages in the prevention of atherosclerosis and coronary heart disease and this is increasingly attributed to the polyphenol compounds in red wine, such as resveratrol. In the present study, we investigated the effect of resveratrol on platelet aggregation in vitro and in vivo. METHODS: Platelet aggregation in rabbits and normal subjects was measured using Born's method. RESULTS: Resveratrol, at 10 - 1000 micromol/L, significantly inhibited platelet aggregation in vitro induced by collagen, thrombin, and ADP in healthy subjects. The inhibitory effect was concentration-dependent. Hypercholesterolemia induced by high-cholesterol diet enhanced ADP-induced platelet aggregation. Resveratrol 4 mg x kg(-1) x d(-1) inhibited ADP-induced platelet aggregation in vivo despite no changes in serum lipid levels. CONCLUSIONS: Resveratrol inhibits platelet aggregation both in vitro and in vivo. This may be one of the mechanisms by which resveratrol prevents atherosclerosis.

Clinical significance of platelet mononuclear cell aggregates in patients with sepsis and acute respiratory distress syndrome

BACKGROUND The diagnosis of sepsis combined with acute respiratory distress syndrome(ARDS)has increased owing to the enhanced awareness among medical profes-sionals and the continuous development of modern medical technologies,while early diagnosis of ARDS still lacks specific biomarkers.One of the main patho-genic mechanisms of sepsis-associated ARDS involves the actions of various pathological injuries and inflammatory factors,such as platelet and white blood cells activation,leading to an increase of surface adhesion molecules.These adhesion molecules further form platelet-white blood cell aggregates,including platelet-mononuclear cell aggregates(PMAs).PMAs has been identified as one of the markers of platelet activation,here we hypothesize that PMAs might play a potential biomarker for the early diagnosis of this complication.METHODS We selected 72 hospitalized patients diagnosed with sepsis as the study population between March 2019 and March 2022.Among them,30 patients with sepsis and ARDS formed the study group,while 42 sepsis patients without ARDS comprised the control group.After diagnosis,venous blood samples were imme-diately collected from all patients.Flow cytometry was employed to analyze the expression of PMAs,platelet neutrophil aggregates(PNAs),and platelet aggregates(PLyAs)in the serum.Additionally,the Acute Physiology and Chronic Health Evaluation(APACHE)II score was calculated for each patient,and receiver operating characteristic curves were generated to assess diagnostic value.RESULTS The study found that the levels of PNAs and PLyAs in the serum of the study group were higher than those in the control group,but the difference was not statistically significant(P>0.05).However,the expression of PMAs in the serum of the study group was significantly upregulated(P<0.05)and positively correlated with the APACHE II score(r=0.671,P<0.05).When using PMAs as a diagnostic indicator,the area under the curve value was 0.957,indicating a high diagnostic value(P<0.05).Furthermore,the optimal cutoff value was 8.418%,with a diagnostic sensitivity of 0.819 and specificity of 0.947.CONCLUSION In summary,the serum levels of PMAs significantly increase in patients with sepsis and ARDS.Therefore,serum PMAs have the potential to become a new biomarker for clinically diagnosing sepsis complicated by ARDS.

Effects of Berbamine on PAF Production in Human Neutrophils and on Platelet Aggregation

The effects of berbamine, an alkaloid of dibenzylisoquinoline, on PAF produc tion in human neutrophils and on platelet aggregation induced by PAF were studied and compared with those of the calcium antagonist verapamil. Preincubation with berbamine (50 mmol / L, 100 mmol / L) or verapamil (10 mmol / L, 100 mmol / L) was shown to significantly inhibit A 23187 stimulated PAF synthesis. Berbamine and verapamil were found to inhibit platelet aggregation induced by PAF 70 pmol / L in a dose dependent manner. These results suggest that the inhibitory effects of berbamine and verapamil on A 23187 stimulated PAF synthesis in human neutrophils and PAF induced platelet aggregation are possibly brought about by inhibiting cellular calcium influx.

Use of tailored loading-dose clopidogrel in patients undergoing selected percutaneous coronary intervention based on adenosine diphosphate-mediated platelet aggregation

Background Adenosine phosphate-mediated platelet aggregation is a prognostic factor for major adverse cardiac events in patients who have undergone selective percutaneous coronary interventions. This study aimed to assess whether an adjusted loading dose of clopidogrel could more effectively inhibit platelet aggregation in patients undergoing selected percutaneous coronary intervention.Methods A total of 205 patients undergoing selected percutaneous coronary intervention were enrolled in this multicenter, prospective, randomized study. Patients receiving domestic clopidogrel （n=104） served as the Talcom （Taijia）group; others （n=101） received Plavix, the Plavix group, Patients received up to 3 additional 300-mg loading doses of clopidogrel to decrease the adenosine phosphate-mediated platelet aggregation index by more than 50% （the primary endpoint） compared with the baseline. The secondary endpoint was major adverse cardiovascular events at 12 months.Results Compared with the rational loading dosage, the tailored loading dosage better inhibited platelet aggregation based on a ＞50% decrease in adenosine phosphate-mediated platelet aggregation （rational loading dosage vs. tailored loading dosage, 48% vs. 73%, P=0.028）. There was no significant difference in the eligible index between the Talcom and Plavix groups （47% vs. 49% at 300 mg; 62% vs. 59% at 600 mg; 74% vs. 72% at 900 mg; P ＞0.05） based on a standard adenosine diphosphate-mediated platelet aggregation decrease of ＞50%. After 12 months of follow-up, there were no significant differences in major adverse cardiac events （2.5% vs. 2.9%, P=5.43）. No acute or subacute stent thrombosis events occurred.Conclusion An adjusted loading dose of clopidogrel could have significant effects on antiplatelet aggregation compared with a rational dose, decreasing 1-year major adverse cardiac events in patients undergoing percutaneous coronary interventions based on adenosine phosphate-mediated platelet aggregation with no increase in bleeding.

Effect on platelet aggregation activity: extracts from 31 Traditional Chinese Medicines with the property of activating blood and resolving stasis

OBJECTIVE: To evaluate the anti-platelet aggregation effects of extracts from 31 Traditional Chinese Medicines(TCM) with the property of activating blood and resolving stasis in terms of TCM theory.METHODS: The 31 TCMs extracts were prepared using water, 90% ethanol and ethyl acetate., and the effects on anti-platelet aggregation were tested on a platelet aggregation analyzer in vitro with adenosine 5'-diphosphate, bovine thrombin and arachi-donic acid(AA) as aggregation inducers, respectively. Aspirin was the positive control.RESULTS: Lots of the tested TCMs had inhibitory effects with concentration-dependent manner on platelet aggregations induced by various agonists.Especially, some of the TCMs such as Chuanxiong(Rhizoma Chuanxiong), Yanhusuo(Rhizoma Corydalis Yanhusuo) and Danshen(Radix Salviae Miltiorrhizae) showed good anti-platelet aggregation effect similar or higher than that in positive control group.CONCLUSION: The study provided scientific references that several TCMs such as Chuanxiong(Rhizoma Chuanxiong), Yanhusuo(Rhizoma Corydalis Yanhusuo) and Danshen(Radix Salviae Miltiorrhizae),possess the property of anti-platelet aggregation.

Effect of Aqueous Extracts of Several Kinds of Herbs on Human Platelet Aggregation and Expression of P-Selectin in Vitro

Objective： To study the effect of aqueous extract of several kinds of herbs on human platelet aggregation and expression of P-selectin in vitro. Methods： Blood was collected from volunteers. Effects of the prepared water extracts of herbs on platelet aggregation were monitored on a Packs-4 aggregometer. The fluorescence intensity of water extracts of Caulis Spatholobi, Flos Carthami and Rhizoma Curcumae on the expression of P-selectin in human platelets of healthy persons was measured with flow cytometry. Results： Out of several herbs investigated, Flos Carthami and Rhizoma Curcumae potently inhibited platelet aggregation after incubation with platelet-rich plasma （PRP） for 15 min. Caulis Spatholobi, Flos Carthami and Rhizoma Curcumae inhibited adenosine-5＇-diphosphate （ADP） or platelet activating factor （PAF）-induced platelet aggregation in PRP in a dose-dependent manner. In contrast to Flos Carthami and Rhizoma Curcumae, Caulis Spatholobi could not inhibit thrombin-induced platelet aggregation. Despite its inability to inhibit thrombin-induced platelet aggregation in PRP, Caulis Spatholobi had a greater anti-aggregating activity in PRP induced by ADP or PAF. Caulis Spatholobi and Flos Carthami showed significant inhibitory effects on the expression of P-selectin. Conclusions： Caulis Spatholobi, Flos Carthami and Rhizoma Curcumae have potent anti-platelet properties, and their inhibitory actions are mediated via different mechanisms. Caulis Spatholobi inhibited ADP-induced platelet aggregation but not by thrombin, indicating that its mechanism of action might be independent of the thromboxane pathway. The effect of Caulis Spatholobi and Flos Carthami were associated with suppressing the expression of P-selectin.

Effect of Desmopressin on Platelet Aggregation and Blood Loss in Patients Undergoing Valvular Heart Surgery

Background：Blood loss after cardiac surgery can be caused by impaired platelet （PLT） function after cardiopulmonary bypass.Desmopressin or 1-deamino-8-D-arginine vasopressin （DDAVP） is a synthetic analog of vasopressin.DDAVP can increase the level of von Willebrand factor and coagulation factor Ⅷ,thus it may enhance PLT function and improve coagulation.In this study,we assessed the effects of DDAVP on PLT aggregation and blood loss in patients undergoing cardiac surgery.Methods：A total of 102 patients undergoing valvular heart surgery （from October 2010 to June 2011） were divided into DDAVP group （n =52） and control group （n =50）.A dose of DDAVP （0.3 μtg/kg） was administered to the patients intravenously when they were being rewarmed.At the same time,an equal volume of saline was given to the patients in the control group.PLT aggregation rate was measured with the AggRAM four-way PLT aggregation measurement instrument.The blood loss and transfusion,hemoglobin levels,PLT counts,and urine outputs at different time were recorded and compared.Results：The postoperative blood loss in the first 6 h was significantly reduced in DDAVP group （202 ± 119 ml vs.258 ± 143 ml,P =0.023）.The incidence of fresh frozen plasma （FFP） transfusion was decreased postoperatively in DDAVP group （3.8% vs.12%,P =0.015）.There was no significant difference in the PLT aggregation,urine volumes,red blood cell transfusions and blood loss after 24 h between two groups.Conclusions：A single dose of DDAVP can reduce the first 6 h blood loss and FFP transfusion postoperatively in patients undergoing valvular heart surgery,but has no effect on PLT aggregation.

Specific inhibiting effects of Ilexonin A on von Willebrand factor-dependent platelet aggregation under high shear rate

Background llexonin A (IA), purified from the Chinese herbal medicine Maodongqing (Ilex pubescens Hook, et Am) has been commonly used in south China to treat thrombotic disorders. In this study, we aimed to study the inhibiting effects and mechanism of IA on von Willebrand factor (vWF)-dependent high shear-induced platelet aggregation.Methods vWF-dependent high shear (10 800 s-1) induced aggregation of platelets obtained from normal donors in the presence or absence of IA was measured by a modified cone-plate viscometer and shear-induced vWF binding was measured by quantitative flowcytometry with monoclonal antibody known to bind exclusively to the C-terminal domain of vWF (LJ-C3) directly labeled with fluorescein isothiocyanate (FITC). P-selectin surface expression was also measured by a similar method with FITC conjugated anti-P-selectin monoclonal antibody (WGA1).Results Shear-induced platelet aggregation was inhibited by IA in a dose-dependent manner. The extent of aggregation decreased from (78. 6 ±4. 6)% in the absence of IA to (36. 5 ±2.1)% in the presence of IA (3. 3 mmol/L) (P<0. 0001, n =9) with a high shear rate of 10800 s-1. vWF binding and P-selectin expression were also inhibited by IA in a dose dependent manner. The number of binding FITC-LJ-C3 molecules increased after exposure of platelet-rich plasma to a high shear rate of 10800 s-1 for 6 minutes, but this shear-induced increased binding platelet surface vWF molecules and P-selectin expression can be decreased in the presence of IA.Conclusion vWF binding and vWF mediated platelet activation, aggregation occurring under high shear rate were inhibited by IA. IA may be a unique antithrombotic drug inhibiting the vWF-GP Ibα interaction, and may thus facilitate drug design targeting arterial thrombosis.

Analysis of anti-platelet aggregation components of Rhizoma Zingiberis using chicken thrombocyte extract and high performance liquid chromatography

Background The conventional procedure for screening bioactive components from traditional Chinese medicine is time-consuming, expensive and low efficient. Therefore, some alternative strategies are needed urgently. A novel method for screening anti-platelet aggregation components from oleoresins was developed using chicken thrombocyte extract and high performance liquid chromatography. Methods The anti-platelet aggregation components of oleoresins were combined with receptors, channels and enzymes of chicken thrombocytes under physiological environment. Unbound substances were washed away and bound compounds were eluted using specific phosphate buffered solution （PBS）. Compounds released from target sites were collected and analyzed by high performance liquid chromatography and LC-MS. The activity of three compounds which were screened from this model was confirmed using platelet aggregation pharmacology in vivo. Results There were four typical compounds that bound to the thrombocytes： 6-gingerol, 8-gingerol, 6-shogaol and 10-gingerol, and all had shown anti-platelet aggregation activities. Eight-gingerol displayed the best anti-platelet aggregation effect. Conclusions Chicken thromobcyte extract can be used to isolate chemicals that are ligands of the receptor or other bio-targets on the platelet. This may therefore be a simple and efficient method to screen for anti-platelet aggregation compounds from traditional Chinese medicine.

Inhibitory Effects of Qushuanling Capsule(祛栓灵胶囊) on Thrombus Formation and Platelet Aggregation in Rats

Objective： To investigate the effects of Qushuanling Capsule （祛栓灵胶囊 QSLC） on thrombus formation and platelet aggregation in rats. Methods： Arteriovenous bypass, venous thrombosis, and middle cerebral artery thrombosis models were used in rats to investigate the anti-thrombotic effects of QSLC, a compound of nine Chinese herbs. The platelet aggregation induced by adenosine diphosphate （ADP）, thrombin or arachidonic acid （AA）, as well as the contents of thromboxane B2 （TXB2） and 6-keto-prostaglandin F1 （6-keto-PGF1 α ） in rat plasma and aortic walls, were determined to investigate the possible mechanisms of the anti-thrombotic effects of QSLC. Results： After oral administration with QSLC for 7 days, arteriovenous bypass thrombosis was obviously suppressed compared with the model group, venous thrombosis was also obviously suppressed, rat behaviors were obviously improved, and brain infarct size as well as water content were also reduced. The platelet aggregation induced by ADP or thrombin was inhibited by QSLC, but the drug had no effect on AA-induced platelet aggregation and content of TXB2 and 6-keto-PGF1α in plasma and the aortic wall. Conclusion： These results suggest that QSLC can be used in the prevention and treatment of thrombotic diseases, and that its mechanism of action may be related to inhibition of platelet aggregation.

Iridoid glycosides extracted from Zhizi(Fructus Gardeniae)decrease collagen-induced platelet aggregation and reduce carotid artery thrombosis in an invivo rat model

OBJECTIVE: To investigate the anti-platelet aggregation and antithrombotic effects in rats of iridoid glycosides extracted from Zhizi (FructusGardeniae). METHODS: The present study evaluated the antithrombotic activity of iridoid glycosides (IGs) in a rat model of carotid artery thrombosis. The effects on coagulation, such as thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT), and the effect on collagen-induced platelet aggregation in vivo were investigated. Rats were intragastrically administered IGs (50, 100 or 200 mg/ kg) twice daily for 3 days. RESULTS: IGs were shown for the first time to have an antithrombotic action through the inhibition of platelet aggregation, with little effect on the coagulation time of peripheral blood. Our results also showed that IGs may significantly and dose-dependently reduce arterial thrombus load in a model of carotid artery thrombosis and inhibit collagen-induced platelet aggregation in rats. IGs (100or 200 mg/kg) had no significant effect on APTT and PT, but did lengthenTT at a higher dose. CONCLUSION: These data, together with the previously reported neuroprotective effects of IGs in rats with cerebral ischemia, suggest that the antithrombotic action of IGs may potentially contribute to the treatment of cerebral ischemic diseases, including cerebral apoplexy.

EFFECT OF 764－3 ON AGGREGATION AND CALCIUM MOVEMENTS IN AEQUORIN－LOADED HUMAN PLATELETS

Washed human platelets were loaded with the Ca2+-sensitive photoprotein, aequorin. using hypoosmotic shock treatment-technique. Then aggregation and cytoplasmic ionized calcium concentration ( [Ca2+] i) changes in response to collagen or thrombin were measured simultaneously in the aequorin-loaded human platelets with a Platelet Ionized Calcium Aggregometer. 764-3. an active component isolated from the Chinese medicinal herb Salvia Miltiorrhiza Bge, inhibited platelet [Ca2+]i rise as well as aggregation evoked by collagen or thrombin in the presence of extracellular Ca2+. After the extracellular Ca2+. was removed by addition of EGTA, collagen or thrombin. causing no aggregation. still elicited platelet [Ca2+] i rise which reflected Ca2+ mobilization from intraplatelet stores. Under this condition, 764-3 could also suppress platelet [Ca2+] i rise. Analysis shows that 764-3 inhibrts platelet Ca2+ influx and Ca2+ mobilization with similar potency. which accounts for its suppression of platelet [Ca2+] i rise, and must contribute to its inhibition of platelet aggregation.