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.

Applying a highly specific and reproducible cDNA RDA method to clone garlic up-regulated genes in human gastric cancer cells

AIM: To develop and optimize cDNA representational difference analysis (cDNA RDA) method and to identify and clone garlic up-regulated genes in human gastric cancer (HGC) cells. METHODS: We performed cDNA RDA method by using abundant double-stranded cDNA messages provided by two self-constructed cDNA libraries (Allitridi-treated and paternal HGC cell line BGC823 cells cDNA libraries respectively). Bam H I and Xho I restriction sites harbored in the library vector were used to select representations. Northern and Slot blots analyses were employed to identify the obtained difference products. RESULTS: Fragments released from the cDNA library vector after restriction endonuclease digestion acted as good marker indicating the appropriate digestion degree for library DNA. Two novel expressed sequence tags (ESTs) and a recombinant gene were obtained. Slot blots result showed a 8-fold increase of glia-derived nexin/protease nexin 1 (GDN/PN1) gene expression level and 4-fold increase of hepatitis B virus x-interacting protein (XIP) mRNA level in BGC823 cells after Allitridi treatment for 72h. CONCLUSION: Elevated levels of GDN/PN1 and XIP mRNAs induced by Allitridi provide valuable molecular evidence for elucidating the garlic's efficacies against neurodegenerative and inflammatory diseases. Isolation of a recombinant gene and two novel ESTs further show cDNA RDA based on cDNA libraries to be a powerful method with high specificity and reproducibility in cloning differentially expressed genes.

Antithrombotic treatment in chronic heart failure and sinus rhythm: Systematic review

AIM: To assess the efficacy and safety of antithrombotic drugs(antiplatelet or anticoagulant drugs) compared to no antithrombotic treatment or placebo in patients with heart failure(HF) and sinus rhythm. METHODS: We searched Medline and Cochrane Library for randomized controlled trials evaluating antithrombotic treatment and no antithrombotic treatment in patients with HF and sinus rhythm. Risk ratio(RR) and 95%CIs were estimated performing meta-analysis with random effects method. RESULTS: Two studies met the inclusion criteria: Heart failure Long-term Antithrombotic Study and Warfarin/Aspirin Study in Heart failure, with 336 patients and mean follow-up 1.8-2.25 years. Stroke risk was not reduced by acetylsalicylic acid(RR = 1.18, 95%CI: 0.17-8.15), oral anticoagulation(RR = 0.30, 95%CI: 0.03-2.65) or overall antithrombotic drugs(RR = 0.52, 95%CI: 0.10-2.74). Acetylsalicylic acid showed a significant increased risk of worsening HF(RR = 1.78, 95%CI: 1.08-2.92), while oral anticoagulation had no impact in this outcome(RR = 1.03, 95%CI: 0.61-1.75). Overall antithrombotic drugs showed a significant risk increase of major bleeding(RR = 6.99, 95%CI: 0.89-54.64). CONCLUSION: Best available evidence does not support the routine use of antithrombotic drugs in patients with HF and sinus rhythm. These drugs, particularly oral anti-coagulation has the hazard of increase significantly major bleeding risk.

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.

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.

A prospective randomized antiplatelet trial of cilostazol versus clopidogrel in patients with bare metal stent

Background Cilostazol is a newly developed antiplatelet drug that has been widely applied for clinical use. Its antiplatelet action appears to be mainly related to inhibition of intracellular phosphodiesterase activity. Recently, cilostazol has been used for antiplatelet therapy after coronary bare metal stent implantation for thrombosis and restenosis prevention. This prospective randomized and double blind trial was designed to investigate the safety and efficacy of cilostazol for the prevention of late restenosis and acute or subacute stent thrombosis. Methods One hundred and twenty patients who underwent elective stent were randomly assigned to treatment group with cilostazol 200 mg/d （n = 60）, clopidogrel 75 mg/d and aspirin 100 mg/d or to control group with clopidogrel treatment 75 mg/d （n = 60） and aspirin 100 mg/d. Follow-up coronary angiography was performed 6--9 months later. Results Nine months major adverse cardio-cerebral event （MACCE） were lower in treatment groups （P〈0.05）. The quantitative coronary angiography （QCA） at 6 months follow-up showed that minimum lumen diameter （MLD） was higher in treatment group than that of control group [（2.14 ± 0.52）mm vs （1.82 ± 0.36）mm, P〈0.05]. Late lumen loss （LL） [（0.82 ± 0.42）mm vs （1.31 ± 0.58）mm; P〈0.01 ], restenosis rate （RR） （14% vs 32%; P〈0.05） and target lesion revascularizaion （TLR） rate （5% vs 17%; P〈0.05） were lower in treatment group than in control group. Conclusion Cilostazol therapy is an effective regimen for prevention not only stent thrombosis but also RR and TLR through reducing MLD without the risk of increasing bleeding.

Clinical Effect of Maixuekang Capsule(脉血康胶囊) on LongTerm Prognosis in Patients with Acute Coronary Syndrome after Percutaneous Coronary Intervention

Objective： To study the changes of adenosine diphosphate （ADP）-induced platelet aggregation rate, and evaluate the effects of Maixuekang Capsule （脉血康胶囊, MKC） on platelet aggregation rate and long-term prognosis of patients with acute coronary syndrome after percutaneous coronary intervention （PCI）. Methods： A total of 236 patients with acute coronary syndrome, who received successful PCI, were randomly assigned to a trial group （116 cases） and a control group （120 cases） according to random numbers; treatment allocation occurred when the participants met the inclusion criteria and signed the informed consent forms. In the trial group, the patients were treated with MKC combined with routine medication, and in the control group the patients were treated with routine medication. The therapeutic course for the two groups was 12 months and the follow-up was 12 months. The levels of ADP-induced platelet aggregation rate and serum high-sensitive C-reactive protein （hs-CRP） were determined before PCI, 12 h and 30 days after PCI. In the meantime, the incidence of cardio-/cerebrovascular events was recorded during the 12-month follow-up. Results： Compared with before PCI, the levels of ADP-induced platelet aggregation rate and serum hs-CRP were significantly higher at 12 h after PCI （P〈0.05）. They were significantly reduced after 30-day-treatment of MKC, showing statistical differences when compared with those in the control group （P〈0.05）. During the 12-month follow-up, the incidence of cardio-/cerebrovascular events was significantly lower in the trial group than in the control group （6.9% vs. 12.5%, P〈0.01）. Conclusions： ADP-induced platelet aggregation function was significantly elevated after PCI. MKC improved the prognosis of patients with acute coronary syndrome, possibly through inhibiting the platelet aggregation, fighting against inflammation, and protecting the vascular endothelial function.

Intensified Antiplatelet Treatment Reduces Major Cardiac Events in Patients with Clopidogrel Low Response： A Meta-analysis of Randomized Controlled Trials

Background：Clopidogrel low response （CLR） is an independent risk factor of adverse outcomes in patients undergoing percutaneous coronary intervention （PCI）,and intensified antiplatelet treatments （IAT） guided by platelet function assays might overcome laboratory CLR.However,whether IAT improves clinical outcomes is controversial.Methods：Relevant trials were identified in PubMed,the Cochrane Library,and the Chinese Medical Journal Network databases from their establishment to September 9,2014.Trials were screened using predefined inclusion criteria.Conventional meta-analysis and cumulative meta-analysis were performed using the Review Manager 5.0 and STATA 12.0 software programs.Results：Thirteen randomized controlled trials involving 5111 patients with CLR were recruited.During a follow-up period of 1-12 months,the incidences of cardiovascular （CV） death,nonfatal myocardial infarction （MI）,and stent thrombosis were significantly lower in the IAT arm than in the conventional antiplatelet treatment arm （relative risk [RR] =0.45,95% confidence interval [CI]：0.36-0.57,P 〈 0.000,01）,whereas bleeding was similar between the two arms （RR =1.05,95% CI：0.86-1.27,P =0.65）.Conclusions：IAT guided by platelet function assays reduces the risk of CV death,nonfatal MI,and stent thrombosis （ST） without an increased risk of bleeding in patients undergoing PCI and with CLR.

Deciphering structural and functional roles of disulfide bonds in decorsin

Decorsin, an antagonist of integrin glycoprotein IIb/IIIa, contains Arg-Gly-Asp （RGD） sequence and three disulfide bridges. The function of RGD sequence has already been well defined, but the roles of conserved disulfide bonds in antihemostatic proteins still remain unclear. Herein we use the fusion expression and characterization of mutant decorsin to study the func- tions of disulfide bonds in protein structure, stability and biological activity. The purified protein shows an apparent inhibition of activity to platelet aggregation induced by ADP with IC50 of 500 nM. The removal of cys7-cysl5 （from cysteine to serine） at the N-terminal causes a thirty-fold decrease of the inhibition activity with IC50 of 15 ~tM, whereas the mutation of cys22-cys38 at the C-terminal completely impairs the biological activity of decorsin. The overall secondary and tertiary struc- tures of decorsin are disrupted inevitably without disulfide bonds. Using a domain insertion mutation, the retaining of RGD loop and the adjacent disulfide bond produces a week antihemostatic activity of decorsin. This reveals that the overall structure of decorsin stabilized by the three conserved disulfide bridges is cooperative for antihemostatic function. Our study on the ef- fect of disulfide bonds together with RGD-sequence on the protein function is helpful for structure-based drug design of an- tithrombotic research.