Panax Notoginseng Saponins And Aspirin Are Based On The Study Of The Interaction Mechanism Of The Arachidonic Acid Pathway

Aspirin(ASA)is a commonly used antiplatelet agent for patients with coronary atherothrombosis.ASA blocks the production of thromboxane(TXA2),a downstream metabolite of AA,via the irreversible acetylation of cyclooxygenase(COX),and inhibits AA-induced platelet activation.Otherwise,ASA impairs COX-mediated generation of prostaglandins(PGs),potentially contributing to gastrointestinal(GI)damage.However,high on-treatment platelet reactivity despite ASA use has been related to increased risk of atherothrombosis.On the other hand,ASA induced GI complications has significantly compromised its clinical adherence.Herein,further studies are warranted to indentify new strategies to achieve greater antiplatelet effect and reduce ASA-related GI damagePanax notoginseng(Burk.)F.H.Chen is the representative traditional Chinese medicine with effect in promoting blood circulation and hemostasis as well as removing blood stasis and generating muscle.Panax notoginseng saponin(PNS)is one of the effective components of Panax notoginseng(Burk.)F.H.Chen.Xuesaitong soft capsules,composed of PNS,have gained wide application in patients with coronary artery disease and blood stasis pattern and those with concomitant GI injuries.Previous in vivo and in vitro studies have demonstrated that PNS combined with dual antiplatelet therapy(ASA+ Clopidogrel)resulted in greater inhibition in platelet aggregation and alleviated gastric mucosal damage,and the underlying mechanism may involve downregulation of serum TXA2 and upregulation of gastric PGI2 and PGE2,but in-depth mechanism remained to be elucidated.AA lipid metabolism pathway is commonly existed in platelets and gastric mucosal epithelial cells.A panel of studies have reported the expansive role of metabolites in AA pathway in platelet activation and inhibition,and their versatile effect on gastric mucosal injury and repairment.To date,it has not been explored that PNS exerts antiplatelet effect and protective effect on gastric mucosa via regulation of AA metabolism.Taken together,we tested the hypothesis that compared with ASA alone,PNS combined with ASA would yield more potent platelet inhibition with alleviated GI damage through regulation of AA pathway by a randomized controlled trial and an in vivo expreriment.Part 1 Panax notoginseng saponin combined with aspirin on patients with stable coronary artery disease and chronic gastritis-a randomized controlled trialObjective:To investigate the effect of PNS combined with low-dose aspirin on platelet function and gastrointestinal complications in patients with concomitant diagnosis of stable coronary heart disease(SCAD)and chronic gastritis(CG).Methods:This is a single center,randomized controlled trial.We randomly assigned 42 patients with SCAD and CG to control group(n=21)or treatment group(n=21),who were given ASA(100mg daily)alone or in combination with Xuesaitong soft capsule(two capsules twice daily)for 2 months,respectively,in addition to standard western medicine.The primary outcomes were platelet function(maximum platelet aggregation rate,platelet CD62p,platelet GPIIb?a)and GI complications(evaluated by severity of dyspepsia assessment score)at 2 months.Secondary outcomes covered ? AA and ADP inhibition rate from thromboelastography,?enzymatic activity of platelet COX-1,?expression of platelet COX-1,?intracellular concentration of cyclic adenosine monophosphate(cAMP)in platelets,?intracellular concentration of lipid metabolites in platelets targeted in AA pathway,?serum levels of motilin and gastrin.Safety outcomes included electrocardiogram,hematology,clinical chemistry(liver function test and kidney function test),clinical urine,fecal occult blood test.Primary outcome,secondary outcomes and safety outcomes were assessed at baseline and at 2 months.Adverse events were monitor throughout the trial.Results:There were no significant differences in baseline characteristics between groups(P>0.05).At 2 months,compared with control group,platelet aggregation in response to AA(P<0.01)and ADP(P<0.05)were significantly reduced in the treatment group;expression and median fluorescence intensity(MFI)of CD62,MFI of GPIIb?a were also significantly lower in the treatment group(all P<0.01);additionally,inhibition rate of AA and ADP induced platelet activation increased significantly in the treatment group(all P<0.01).At 2 months,PNS combined with ASA lead to significantly decreased expression(P<0.05)and enzymatic activity(P<0.01)of platelet COX-1 but rendered significantly increased intracellular level of cAMP in platelets stimulated with ADP(P<0.01),compared with PNS alone.At 2 months,the score of GI symptoms showed significant decrease with significant improvement of the score of satisfaction in patients treated with PNS and ASA relative to those receiving ASA alone(all P<0.01).With respect to platelet lipidomic analysis,intracellular levels of TXB2(P<0.01),PGD2(P<0.01),PGE2(P<0.05),11-HETE(P<0.05),12-HETE(P<0.01),12-HEPE(P<0.05)in treatment group decreased significantly compared with those in comtrol group.PNS combined with ASA achieved greater inhibition of platelet activation,the mechanism by which may involve decreased production of platelet TXA2 and 12-HETE via downregulation of AA-COX and AA-12-LOX pathway.Conclusion:Compared with ASA alone,PNS combined with ASA achieved greater inhibition of platelet activation,relieved GI symptoms and increased level of serum motilin and gastrin.Supressed production of TXA2 and 12-HETE via downregulation of platelet AA-COX and AA-12-LOX pathway may underlie the greater inhibition of platelet activation achieved by PNS combined with ASA,compared with ASA alone.Part 2 Effect of ASA combined with ASA on platelet activation and gastric mucosa injury in rats with acute myocardial infarctionObjective:This in vivo study was designed to evaluate the effect of combination of PNS and ASA on platelet inhibition and gastric mucosa protection in rats with acute myocardial infarction(AMI)and to explore the mechanism through arachidonic acid(AA)metabolic pathway.Methods:Wistar rats subjected to left anterior descending coronary ligation were randomly allocated to AMI group,PNS group,ASA group,PNS+ASA group,with those to sham group undergoing the same surgery except for ligation(n=12 for each group).24 hours after surgery,rats in each drug group were administered with PNS(118.8mg/kg/d for 30 days),ASA(31.25mg/kg/d as loading dose for day 1,31.25mg/kg/d as maintenance dose for days 2-30)or both,and those in sham and AMI group were treated with saline for 30 days.Myocardial infarction area was evaluated by 2,3,5-triphenyltetrazolium chloride(TTC)staining,and myocardial pathological characteristics were illustrated by hematoxylin eosin(HE)staining.Platelet aggregation was assessed by turbidimetry.Gastric mucosa was observed by scanning electron microscope.Platelet COX-1 expression and activity were examined with western blotting and ELISA,respectively.Metabolites in AA pathway in gastric mucosa,TXA2 and 12-HETE in platelets were measured by liquid Chromatograph-Mass Spectrometer(LC-MS).Enzymatic activity of platelet COX-1,intracellular level of cAMP in platelets were measured by ELISA.Expression of platelet COX-1 were evaluated by western blot.Results:Myocardial infarction size in PNS group,ASA group and PNS+ASA group were markedly reduced with platelet aggregation rate markedly decreased relative to those in AMI group(all P<0.01).Enzymatic activity and expression of platelet COX-1 showed significant decrease in PNS group,ASA group and PNS+ASA group compared with AMI group(all P<0.01),which were significantly reduced in PNS+ASA group when compared with ASA group(all P<0.01).ASA induced gastric mucosa injuries,characterized by exfoliation of microvilli and gastric epithelial cells coupled with explosion of connective tissues,which were relieved in PNS+ASA group.Compared with ASA group,concentration gastric levels of 6,15-diketo-13,14-dihydro-PGF1a,13,14-dihydro-15-keto-PGE2,PGE1,downstream metabolites of AA-COX pathway,increased significantly while LTC4,downstream metabolite of AA-LOX pathway and 8-iso-PGF2a,8-iso-PGE2,8-iso-PGE2,radical-mediated metabolites of AA,were markedly decreased in PNS+ASA group(all P<0.01).Alleviated gastric damage was observed in PNS+ASA group,the mechanism by which may involve upregulation of AA-COX-PG pathway,downregulation of AA-LOX-LT and AA radical pathway.Conclusion:Compared with ASA alone,combining PNS with ASA further inhibited platelet aggregation due to decreased production of TXA2 and 12-HETE in platelets.PNS mitigated ASA induced gastric injury,which may be related to upregulation of AA-COX-PG pathway,downregulation of AA-LOX-LT and AA radical pathway.