Monitoring Antiplatelet Aggregation In Vivo and In Vitro by Microtiter Plate Method

Anti-atherogenic role of green tea (Camellia sinensis) in South Indian smokers

ETHNOPHARMACOLOGICAL RELEVANCE

Green tea (Camellia sinensis) is a popular beverage consumed all over the world due to its health benefits. Many of these beneficial effects of green tea are attributed to polyphenols, particularly catechins.

AIM OF THE STUDY

The present study focuses on underlying anti-platelet aggregation, anti-thrombotic, and anti-lipidemic molecular mechanisms of green tea in South Indian smokers.

MATERIALS AND METHODS

We selected 120 South Indian male volunteers for this study to collect the blood and categorised them into four groups; control group individuals (Controls), smokers, healthy control individuals consuming green tea, and smokers consuming green tea. Smokers group subjects have been smoking an average 16-18 cigarettes per day for the last 7 years or more. The subjects (green tea consumed groups) consumed 100 mL of green tea each time, thrice a day for a one-year period.

RESULTS

LC-MS analysis revealed the presence of multiple phytocompounds along with catechins in green tea extract. Increased plasma lipid peroxidation (LPO), protein carbonyls, cholesterol, triglycerides, and LDL-cholesterol with decreased HDL-cholesterol levels were observed in smokers compared to the control group and the consumption of green tea showed beneficial effect. Furthermore, docking studies revealed that natural compounds of green tea had high binding capacity with 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA) when compared to their positive controls, whereas (-) epigallocatechin-3-gallate (EGCG) and (-) epicatechin-gallate (ECG) had high binding capacity with sterol regulatory element-binding transcription factor 1 (SREBP1c). Further, our ex vivo studies showed that green tea extract (GTE) significantly inhibited platelet aggregation and increased thrombolytic activity in a dose dependent manner.

CONCLUSION

In conclusion, in smokers, catechins synergistically lowered oxidative stress, platelet aggregation and modified the aberrant lipid profile. Furthermore, molecular docking studies supported green tea catechins' antihyperlipidemic efficacy through strong inhibitory activity on HMG-CoA reductase and SREBP1c. The mitigating effects of green tea on cardiovascular disease risk factors in smokers that have been reported can be attributed majorly to catechins or to their synergistic effects.

Antiplatelet activity and toxicity profile of novel phosphonium salts derived from Michael reaction

In this work, five novel phosphonium salts derived from the Michael reaction were screened for their antiplatelet activity. Our findings revealed that compounds 2a, 2b, 2c, and 2d significantly inhibit platelet aggregation triggered by ADP or collagen (P < 0.001). Notably, compound 2c inhibited the arachidonic acid pathway (P < 0.001). Moreover, the selected compounds reduce CD62-P expression and inhibit GPIIb/IIIa activation. The interactions of the active compounds with their targets, ADP and collagen receptors, P2Y12 and GPVI respectively were investigated in silico using molecular docking studies. The results revealed a strong affinity of the active compounds for P2Y12 and GPVI. Additionally, cytotoxicity assays on platelets, erythrocytes, and human embryonic kidney HEK293 cells showed that compounds 2a, 2c and 2d were non-toxic even at high concentrations. In summary, our study shows that phosphonium salts can have strong antiplatelet power and suggests that compounds 2a, 2c and 2d could be promising antiplatelet agents for the management of cardiovascular diseases.

Antiplatelet Agents Inhibit Platelet Adhesion and Aggregation on Glass Surface Under Physiological Flow Conditions: Toward a Microfluidic Platelet Functional Assay Without Additional Adhesion Protein Modification

ABSTRACT

As the pathogenesis of arterial thrombosis often includes platelet adhesion and aggregation, antiplatelet agents are commonly used to prevent thromboembolic events. Here, a new microfluidic method without additional adhesion protein modification was developed to quantify the inhibitory effect of antiplatelet drugs on the adhesion and aggregation behavior of platelets on glass surfaces under physiological flow conditions. Polydimethylsiloxane-glass microfluidic chips were fabricated by soft photolithography. Blood samples from healthy volunteers or patients before and after taking antiplatelet drugs flowed through the microchannels at wall shear rates of 300 and 1500 second -1 , respectively. The time to reach 2.5% platelet aggregation surface coverage (Ti), surface coverage (A 150s ), and mean fluorescence intensity (F 150s ) were used as quantitative indicators. Aspirin (80 μM) prolonged Ti and reduced F 150s . Alprostadil, ticagrelor, eptifibatide, and tirofiban prolonged Ti and reduced A 150s and F 150s in a concentration-dependent manner, whereas high concentrations of alprostadil did not completely inhibit platelet aggregation. Aspirin combined with ticagrelor synergistically inhibited platelet adhesion and aggregation; GPIb-IX-von Willebrand factor inhibitors partially inhibited platelet aggregation, and the inhibition was more pronounced at 1500 than at 300 second -1 . Patient administration of aspirin or (and) clopidogrel inhibited platelet adhesion and aggregation on the glass surface under flow conditions. This technology is capable of distinguishing the pharmacological effects of various antiplatelet drugs on inhibition of platelet adhesion aggregation on glass surface under physiological flow conditions, which providing a new way to develop microfluidic platelet function detection method without additional adhesive protein modification for determining the inhibitory effects of antiplatelet drugs in the clinical setting.

Multi-omics and network pharmacology study reveals the effects of Dengzhan Shengmai capsule against neuroinflammatory injury and thrombosis induced by ischemic stroke

ETHNOPHARMACOLOGICAL RELEVANCE

Dengzhan Shengmai capsule (DZSM) is a traditional herb medicine used by Dai, an ethnic-minority community living in Xishuang banna tropical rainforest in Southwest of China. It was originally intended to treat disorders caused by insufficient brain function, characterized by gibberish, unresponsiveness, or confusion. Accumulating clinical evidences exhibited that it is effective on treating ischemic stroke (IS). However, the action of DZSM against IS needs to be further elucidated.

AIM OF THE STUDY

To investigate the effect of DZSM and its active components against IS and the way of its action by multi-omics and network pharmacology.

MATERIALS AND METHODS

A middle cerebral artery occlusion/reperfusion (MCAO/R) rat model was established to investigate the effect of DZSM on the focal cerebral ischemia/reperfusion injury. An integrated strategy combining metabolomics, network pharmacology and transcriptomics was performed to systematically clarify the underlying mechanism of action of DZSM against IS. AutoDock Vina was applied to conduct molecular docking simulation for the binding between the potential active compounds and targets. Arachidonic acid (AA) induced platelet aggregation and lipopolysaccharide (LPS) stimulated microglial cells BV2 inflammation models were applied for the in vitro validation of effects of DZSM and its potential active compounds.

RESULTS

In MCAO/R rats, DZSM could significantly reduce the infarct volume. Putative target prediction and functional enrichment analysis based on network pharmacological indicated that the key targets and the potential active compounds played important roles in DZSM's treatment to IS. The targets included four common genes (PTGS1, PTGS2, NFKB1 and NR1I2) and five key TFs (NFKB1, RELA, HIF1A, ESR1 and HDAC1), whilst 22 potential active compounds were identified. Molecular docking indicated that good binding affinity have been seen between those compounds and NR1I2, NFKB1, and RELA. Multi-omics study revealed that DZSM could regulate glutamate by influencing citrate cycle and glutamate involved pathways, and have showed neuroprotection activity and anti-inflammation activity by inhibiting NF-κB pathway. Neuroprotective effects of DZSM was validated by regulating of NF-κB signaling pathway and its downstream NO, TNF-α and IL-6 cytokines contributed to the activity of DZSM and its active compounds of scutellarin, quercetin 3-O-glucuronide, ginsenoside Rb1, schizandrol A and 3, 5-diCQA, whilst the antithrombotic activity of DZSM and its active compounds of schisanhenol, apigenin and schisantherin B were screened out by anti-platelet aggregation experiment.

CONCLUSION

DZSM could against IS via regulating its downstream NO, TNF-α and IL-6 cytokines through NF-κB signaling pathway and alleviating thrombosis.

Systemic Delivery of Clopidogrel Inhibits Neointimal Formation in a Mouse Vein Graft Model

ABSTRACT

Clopidogrel inhibits platelet aggregation and has beneficial effects on patients undergoing coronary artery bypass grafting surgery, but it is unknown whether clopidogrel inhibits the neointima formation of grafted veins. In this study, we used a murine vein graft model to study the effect of clopidogrel on intima hyperplasia of the vein graft. Vein grafting was performed among C57BL/6J mice, immediately after surgery; 1 mg/kg clopidogrel and vehicle control were used to inject mice peritoneally daily for 2 weeks. As compared with the vehicle, clopidogrel significantly inhibited the neointima formation of vein grafts at 4 weeks after surgeries. The immunohistochemistry study showed that as compared with the vehicle, clopidogrel significantly decreased the rate of proliferating cell nuclear antigen-positive cells in the wall of vein grafts and significantly increased the expression of vascular smooth muscle cell (VSMC) contractile protein markers (α-smooth muscle actin, calponin, and SM22) within the neointima area of vein grafts. Clopidogrel significantly decreased the plasma interleukin 6 (IL-6) level at 1 week after surgery as compared with the vehicle. We isolated VSMCs from mouse aortic arteries. As compared with the vehicle, clopidogrel significantly inhibited thrombin-induced VSMC proliferation and migration, significantly decreased IL-6 mRNA expression and protein secretion, and increased intracellular cyclic adenosine monophosphate generation in a dose-dependent manner. In conclusion, systemic delivery of clopidogrel inhibits neointima formation of the mouse vein graft, the mechanisms of which are associated with its inhibitory effects on VSMC proliferation, migration, and the tendency to synthetic phenotype after vein graft surgery, reducing the expression of IL-6 and increasing the intracellular cyclic adenosine monophosphate level.

Improving the Quality of EDTA-treated Blood Specimens from Mice

Nonterminal blood sampling in laboratory mice is a very common procedure. With the goal of improving animal welfare, different sampling sites and methods have been compared but have not achieved a consensus. Moreover, most of these studies overlooked the quality of blood specimens collected. The main preanalytical concern with EDTA-treated blood specimens for hematology analyses is platelet aggregation, which is known to cause analytical errors. Our objective was to find a nonterminal blood sampling method with minimal adverse effects on mice and few or no platelet aggregates. We tested and compared 2 collection sites, 4 sampling methods, and 3 antithrombotic drugs in 80 C57BL6/j male and female mice by evaluating platelet aggregates on blood smears and platelet, WBC, and RBC counts. In addition, the blood collection process was carefully evaluated, and adverse effects were recorded. Platelet aggregation was lower in specimens collected from the jugular vein than from the facial vein, with no effect of the sampling device or the presence of an antithrombotic additive. Highly aggregated specimens were significantly associated with lower platelet counts, whereas aggregation had no effect on WBC or RBC counts. Adverse events during sampling were significantly associated with more numerous platelet aggregates. The jugular vein is thus a satisfactory sampling site in mice in terms of both animal welfare and low platelet aggregation. Using antithrombotic agents appears to be unnecessary, whereas improving sampling conditions remains a key requirement to ensure the quality of EDTA-treated blood specimens from mice.

Ticlopidine induces cardiotoxicity in zebrafish embryos through AHR-mediated oxidative stress signaling pathway

Ticlopidine has inhibitory effects on platelet aggregation via ADP (adenosine diphosphate), platelet release reaction and depolymerization. In clinical practice, it is commonly used to prevent heart, cerebrovascular and other thromboembolic diseases. However, ticlopidine has also been reported to have teratogenic effects on the heart, though its specific molecular mechanism remains unclear. In this study, zebrafish embryos were used as model organisms to examine the toxicity effect of ticlopidine. Zebrafish embryos exposed to 6, 7.5, and 9 mg/L ticlopidine solutions manifested several abnormalities, including body curvature, smaller eyes, slower absorption of the vitella sac, pericardial edema, slower heart rate, increased mortality, longer venous sinus - arterial ball (SV-BA) distance, and increased oxidative stress, which indicated developmental and cardiac toxicity. Abnormal expression of key genes related to heart development was observed, and the level of apoptotic gene expression was up-regulated. Further experiments revealed up-regulation of embryonic oxidative stress following ticlopidine exposure, leading to a decrease in cardiomyocyte proliferation. Conversely, the aromatic hydrocarbon receptor (AHR) inhibitor CH223191 protected embryos from the cardiotoxicity effect of ticlopidine, confirming further the role of up-regulated oxidative stress as the molecular mechanism of ticlopidine-induced cardiotoxicity in zebrafish. In conclusion, ticlopidine exposure leads to developmental and cardiotoxicity in zebrafish embryos. Therefore, further studies are warranted to ascertain such potential harms of ticlopidine in humans, which are vital in providing guidance in the safe use of drugs in clinical practice.

The Synergistic Effect of Ginkgo biloba Extract 50 and Aspirin Against Platelet Aggregation

Purpose

We aimed to investigate potential synergistic antiplatelet effects of Ginkgo biloba extract (GBE50) in combination with aspirin using in vitro models.

Methods

Arachidonic acid (AA), platelet activating factor (PAF), adenosine 5'-diphosphate (ADP) and collagen were used as inducers. The antiplatelet effects of GBE50, aspirin and 1:1 combination of GBE50 and aspirin were detected by microplate method using rabbit platelets. Synergy finder 2.0 was used to analyze the synergistic antiplatelet effect. The compounds in GBE50 were identified by UPLC-Q/TOF-MS analysis and the candidate compounds were screened by TCMSP database. The targets of candidate compounds and aspirin were obtained in TCMSP, CCGs, Swiss target prediction database and drugbank. Targets involving platelet aggregation were obtained from GenCLiP database. Compound-target network was constructed and GO and KEGG enrichment analyses were performed to identify the critical biological processes and signaling pathways. The levels of thromboxane B2 (TXB2), cyclic adenosine monophosphate (cAMP) and PAF receptor (PAFR) were detected by ELISA to determine the effects of GBE50, aspirin and their combination on these pathways.

Results

GBE50 combined with aspirin inhibited platelet aggregation more effectively. The combination displayed synergistic antiplatelet effects in AA-induced platelet aggregation, and additive antiplatelet effects occurred in PAF, ADP and collagen induced platelet aggregation. Seven compounds were identified as candidate compounds in GBE50. Enrichment analyses revealed that GBE50 could interfere with platelet aggregation via cAMP pathway, AA metabolism and calcium signaling pathway, and aspirin could regulate platelet aggregation through AA metabolism and platelet activation. ELISA experiments showed that GBE50 combined with aspirin could increase cAMP levels in resting platelets, and decreased the levels of TXB2 and PAFR.

Conclusion

Our study indicated that GBE50 combined with aspirin could enhance the antiplatelet effects. They exerted both synergistic and additive effects in restraining platelet aggregation. The study highlighted the potential application of GBE50 as a supplementary therapy to treat thrombosis-related diseases.

Systems pharmacological study illustrates the immune regulation, anti-infection, anti-inflammation, and multi-organ protection mechanism of Qing-Fei-Pai-Du decoction in the treatment of COVID-19

BACKGROUND

The traditional Chinese medicine (TCM) formula Qing-Fei-Pai-Du decoction (QFPDD) was the most widely used prescription in China's campaign to contain COVID-19, which has exhibited positive effects. However, the underlying mode of action is largely unknown.

PURPOSE

A systems pharmacology strategy was proposed to investigate the mechanisms of QFPDD against COVID-19 from molecule, pathway and network levels.

STUDY DESIGN AND METHODS

The systems pharmacological approach consisted of text mining, target prediction, data integration, network study, bioinformatics analysis, molecular docking, and pharmacological validation. Especially, we proposed a scoring method to measure the confidence of targets identified by prediction and text mining, while a novel scheme was used to identify important targets from 4 aspects.

RESULTS

623 high-confidence targets of QFPDD's 12 active compounds were identified, 88 of which were overlapped with genes affected by SARS-CoV-2 infection. These targets were found to be involved in biological processes related with the development of COVID-19, such as pattern recognition receptor signaling, interleukin signaling, cell growth and death, hemostasis, and injuries of the nervous, sensory, circulatory, and digestive systems. Comprehensive network and pathway analysis were used to identify 55 important targets, which regulated 5 functional modules corresponding to QFPDD's effects in immune regulation, anti-infection, anti-inflammation, and multi-organ protection, respectively. Four compounds (baicalin, glycyrrhizic acid, hesperidin, and hyperoside) and 7 targets (AKT1, TNF-α, IL6, PTGS2, HMOX1, IL10, and TP53) were key molecules related to QFPDD's effects. Molecular docking verified that QFPDD's compounds may bind to 6 host proteins that interact with SARS-CoV-2 proteins, further supported the anti-virus effect of QFPDD. At last, in intro experiments validated QFPDD's important effects, including the inhibition of IL6, CCL2, TNF-α, NF-κB, PTGS1/2, CYP1A1, CYP3A4 activity, the up-regulation of IL10 expression, and repressing platelet aggregation.

CONCLUSION

This work illustrated that QFPDD could exhibit immune regulation, anti-infection, anti-inflammation, and multi-organ protection. It may strengthen the understanding of QFPDD and facilitate more application of this formula in the campaign to SARS-CoV-2.