Oxypeucedanin is a Mechanism-based Inactivator of CYP2B6 and CYP2D6.

BACKGROUND: Herbal medicine Angelica dahurica is widely employed for the treatment of rheumatism and pain relief in China. Oxypeucedanin is a major component in the herb. OBJECTIVES: The objectives of this study are aimed at the investigation of mechanism-based inactivation of CYP2B6 and CYP2D6 by oxypeucedanin, characterization of the reactive metabolites associated with the enzyme inactivation, and identification of the P450s participating in the bioactivation of oxypeucedanin. METHODS: Oxypeucedanin was incubated with liver microsomes or recombinant CYPs2B6 and 2D6 under designed conditions, and the enzyme activities were measured by monitoring the generation of the corresponding products. The resulting reactive intermediates were trapped with GSH and analyzed by LC-MS/MS. RESULTS: Microsomal incubation with oxypeucedanin induced a time-, concentration-, and NADPH-dependent inhibition of CYPs2B6 and 2D6 with kinetic values of KI/kinact 1.82 µM/0.07 min-1 (CYP2B6) and 8.47 µM/0.044 min-1 (CYP2D6), respectively. Ticlopidine and quinidine attenuated the observed time-dependent enzyme inhibitions. An epoxide and/or γ-ketoenal intermediate(s) derived from oxypeucedanin was/were trapped in microsomal incubations. CYP3A4 was the primary enzyme involved in the bioactivation of oxypeucedanin. CONCLUSION: Oxypeucedanin was a mechanism-based inactivator of CYP2B6 and CYP2D6. An epoxide and/or γ- ketoenal intermediate(s) may be responsible for the inactivation of the two enzymes.

Panax quinquefolius saponins combined with dual antiplatelet drug therapy alleviate gastric mucosal injury and thrombogenesis through the COX/PG pathway in a rat model of acute myocardial infarction.

OBJECTIVES: Previous studies have found that Panax quinquefolius saponins (PQS) combined with dual antiplatelet therapy (DAPT) of aspirin and clopidogrel enhances antithrombotic effects while reducing gastric mucosal injury induced by DAPT. We investigated the effects of the combined drug therapy (PQS+DAPT) through the COX/PG pathways. METHODS: Acute myocardial infarction (AMI) was induced in Wistar rats by ligation of the left anterior descending (LAD) coronary artery, and the animals were randomly divided into Model, DAPT, and PQS+DAPT groups. Rats in the sham group did not undergo artery ligation. They were intragastrically treated for 14 days. Myocardial infarct size; myocardial pathology; platelet aggregation rate, CD62p activation, concentrations of thromboxane B2 (TXB2), 6-keto-PGF1α, tissue plasminogen activator (t-PA), and plasminogen activator inhibitor (PAI), the TXB2/6-keto-PGF1α ratio were measured. The ultrastructure of the gastric mucosa was observed by scanning electron microscopy. The expression of PGE2 and 6-keto-PGF1α in gastric mucosa was measured by radioimmunoassay, and levels of COX-1, COX-2, and VEGF in gastric mucosa were assessed using immunohistochemistry. RESULTS: The addition of Panax quinquefolius saponins (PQS+DAPT) to standard DAPT therapy significantly decreased the myocardial infarct area, degree of myocardial lesions, TXB2 and PAI levels, and the TXB2/6-keto-PGF1α ratio, while increasing 6-keto-PGF1α and t-PA levels and reducing the degree of gastric mucosal injury. Expression of PGE2, 6-keto-PGF1α, COX-2, and VEGF in the gastric mucosa was upregulated in the PQS+DAPT group compared with the standard DAPT group. CONCLUSION: PQS increases the degree of DAPT inhibition of myocardial necrosis and antiplatelet effects in AMI rats, as well as reducing damage to the gastric mucosa caused by DAPT. The mechanism may be related to inhibition of TXB2 and PAI activity and elevation of 6-keto-PGF1α and t-PA levels in blood, and may be associated with upregulated expression of COX-2, PGE2, PGI2, and VEGF in gastric tissue.

Enzyme Kinetics and Molecular Docking Studies on Cytochrome 2B6, 2C19, 2E1, and 3A4 Activities by Sauchinone.

Sauchinone, an active lignan isolated from the aerial parts of Saururus chinensis (Saururaceae), exhibits anti-inflammatory, anti-obesity, anti-hyperglycemic, and anti-hepatic steatosis effects. As herb-drug interaction (HDI) through cytochrome P450s (CYPs)-mediated metabolism limits clinical application of herbs and drugs in combination, this study sought to explore the enzyme kinetics of sauchinone towards CYP inhibition in in vitro human liver microsomes (HLMs) and in vivo mice studies and computational molecular docking analysis. In in vitro HLMs, sauchinone reversibly inhibited CYP2B6, 2C19, 2E1, and 3A4 activities in non-competitive modes, showing inhibition constant (Ki) values of 14.3, 16.8, 41.7, and 6.84 µM, respectively. Also, sauchinone time-dependently inhibited CYP2B6, 2E1 and 3A4 activities in vitro HLMs. Molecular docking study showed that sauchinone could be bound to a few key amino acid residues in the active site of CYP2B6, 2C19, 2E1, and 3A4. When sibutramine, clopidogrel, or chlorzoxazone was co-administered with sauchinone to mice, the systemic exposure of each drug was increased compared to that without sauchinone, because sauchinone reduced the metabolic clearance of each drug. In conclusion, when sauchinone was co-treated with drugs metabolized via CYP2B6, 2C19, 2E1, or 3A4, sauchinone-drug interactions occurred because sauchinone inhibited the CYP-mediated metabolic activities.

Add-on Antiplatelet Effects of Eicosapentaenoic Acid With Tailored Dose Setting in Patients on Dual Antiplatelet Therapy.

The aim of this study was to investigate the antiplatelet effects of eicosapentaenoic acid (EPA) at a sufficient dose following coronary stent implantation. Thirty-one patients on dual antiplatelet therapy with aspirin and clopidogrel were treated with highly purified EPA-E (Epadel®) for 12 weeks. Based on our previous study, patients with a high baseline EPA/arachidonic acid (AA) ratio (≥ 0.37; n = 11) were given a standard dose (1800 mg daily) of EPA-E, whereas those with a low EPA/AA ratio (< 0.37; n = 20) were given a high dose (2700 mg daily) to reach the target value of > 0.92. Platelet function was then evaluated with agonist-induced aggregation using light transmittance aggregometry and VerifyNow®. After EPA-E treatment, the EPA/AA ratio significantly increased from 0.28 to 1.31 (P < 0.001). Collagen (1, 2, and 4 µg/mL)-induced maximal platelet aggregation (MPA) was significantly suppressed after EPA-E administration (from 28.0 to 24.0, P = 0.033; from 44.0 to 40.0, P = 0.016; from 60.0 to 56.0, P = 0.010; respectively). However, there were no changes in MPA induced by adenosine diphosphate and AA and in P2Y12 reaction units (PRU) and aspirin reaction units. After EPA-E treatment, PRU was significantly suppressed in 8 patients showing high on-treatment platelet reactivity (HTPR) (baseline 305; 266-321 versus on-treatment 256; 233-261, P = 0.012), but not in those without HTPR (201; 156-220 versus 183; 159-233, P = 0.212). In conclusion, EPA treatment at a sufficient dose suppressed platelet aggregation and showed possible add-on effects in patients with clopidogrel hyporesponsiveness.

Vitamin D levels and high-residual platelet reactivity in patients receiving dual antiplatelet therapy with clopidogrel or ticagrelor.

BACKGROUND: Suboptimal platelet inhibition still represents an important challenge, especially for patients undergoing percutaneous coronary interventions (PCIs). However, very few are known so far on the predictors of high-residual platelet reactivity (HRPR) despite antiplatelet strategies. Increasing attention has been paid in the last years to the role of vitamin D in atherothrombosis. Therefore, the aim of our study was to evaluate the impact of vitamin D levels on platelet function in patients treated with dual antiplatelet therapy (DAPT). Patients treated with DAPT (ASA and clopidogrel or ticagrelor) after a recent acute coronary syndrome (ACS) or elective PCI were scheduled for platelet function assessment at 30-90 days post-discharge. Platelet function was assessed by whole blood impedance aggregometry (Multiplate®-Roche Diagnostics AG), HRPR was considered for ASPI test values > 862 AU*min (for ASA) and adenosine diphosphate (ADP) test values ≥417 AU*min (for ADP-antagonists). Fasting samples were obtained for main chemistry parameters and vitamin D level assessment. Our population is represented by 503 patients, who were divided according to vitamin D quartiles (≤9.1; 9.2-14.4; 14.5-21.7; >21.7 ng/ml). Lower vitamin D levels related with age (p = 0.04), diabetic status (p = 0.05), and previous coronary surgery (p = 0.007), therapy with beta-blockers and statins (p = 0.01 and p = 0.02). Vitamin D inversely related to the levels of total cholesterol (p = 0.01), triglycerides (p < 0.001), hemoglobin (p = 0.05), and HbA1c (p < 0.001). Significantly higher platelet reactivity was observed after platelet stimulation with ADP (p = 0.01), but not with other platelet activators. The prevalence of HRPR for ASA was low (1.2%) and not conditioned by Vitamin D levels (adjusted OR[95%CI] = 1.56[0.71-3.5], p = 0.27). HRPR with ADP-antagonists was observed in 26% of patients, and the rate increased with lower vitamin D quartiles (37.3% vs 22.2% vs 24.4% vs 20.2%, p = 0.005, adjusted OR[95%CI] = 1.23[1.02-1.49], p = 0.04). An absolute increase in HRPR with lower vitamin D levels was similarly observed among patients receiving ticagrelor (adjusted OR[95% CI] = 1.40[0.95-2.06], p = 0.08), and those on clopidogrel (adjusted OR[95%CI] = 1.31[0.99-1.75], p = 0.06). Thus, lower vitamin D levels are associated with higher platelet reactivity and impaired effectiveness of ADP-antagonists, while not influencing the effectiveness of ASA. Future studies will tell whether vitamin D supplementation can reduce platelet reactivity, overcoming the phenomenon of resistance to antiplatelet agents.

Panax quinquefolium saponin combined with dual antiplatelet drugs inhibits platelet adhesion to injured HUVECs via PI3K/AKT and COX pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: Panax quinquefolium saponin (PQS) is the active component extracted from traditional Chinese medicine Panax quinquefolius L. and has been widely used as a supplement to dual antiplatelet drugs (DA) for treatment of coronary artery disease (CAD) for two decades; however, the efficacy of PQS combined with DA against platelet adhesion to endothelial cells (ECs), an essential step in thrombosis, remains unclear. AIM OF THE STUDY: To compare PQS combined with DA and DA alone in inhibiting platelet adhesion to injured human umbilical vein endothelial cells (HUVECs) and to explore the possible mechanisms focusing on PI3K/AKT, COX-2/6-keto-PGF1α, and COX-1/TXB2 pathways. METHODS: HUVECs injured by oxidized low-density lipoprotein (ox-LDL) were randomly allocated into control, model, DA, PQS+DA (P+DA), LY294002 (a PI3K inhibitor)+DA (L+DA), and LY294002+PQS+DA (LP+DA) groups. HUVEC apoptosis, platelet adhesion to injured HUVECs, and platelet CD62p expression were assayed by fluorescence activated cell sorting (FACS). The concentrations of 6-keto-PGF1α and TXB2 in the supernatant were measured by radioimmunoassay. Protein expression of phosphorylated-PI3K, PI3K, phosphorylated-AKT, AKT, COX-1, and COX-2 in both platelets and HUVECs was evaluated by western blot. RESULTS: Compared to DA alone, PQS combined with DA reduced platelet adhesion to HUVECs and HUVEC apoptosis more potently, increased the concentration of supernatant 6-keto-PGF1α and up-regulated phospho-AKT protein in HUVECs. LY294002 mitigated the effects of PQS on HUVEC apoptosis and platelet adhesion. CONCLUSIONS: These findings show that PQS as a powerful supplement to DA, attenuated HUVEC apoptosis and improved the DA-mediated reduction of platelet adhesion to injured HUVECs and the underlying mechanisms may be associated with PI3K/AKT and COX pathways in HUVECs and platelets. PQS might provide a new complementary approach to improve the prognosis of thrombotic diseases in future.

Protective effects of ginseng extracts and common anti-aggregant drugs on ischaemia-reperfusion injury.

OBJECTIVE: Ginseng is a traditional herbal medicinal product widely used for various types of diseases because of its cellular protective effects. Possible protective effects of ginseng were investigated in blood, cardiac and renal tissue samples and compared with common anti-aggregant agents in an animal ischaemia-reperfusion (I/R) model. METHODS: Twenty rats were equally divided into four different groups as follows: control group (I/R-induced group without drug use), group I (acetylsalicylic acid-administered group), group II (clopidogrel bisulfate-administered group), group III (ginsenoside Rb1-administered group). For the groups assigned to a medication, peripheral I/R was induced by clamping the femoral artery one week after initiation of the specified medication. After reperfusion was initiated, cardiac and renal tissues and blood samples were obtained from each rat with subsequent analysis of nitrogen oxide (NOx), malondialdehyde (MDA), paraoxonase 1 (PON1) and prolidase. RESULTS: NOx levels were similar in each group. Significant decrements were observed in serum PON1 levels in each group when compared with the control (p < 0.05). Serum MDA levels were significantly lower in groups II and III (p < 0.05). Ameliorated renal prolidase levels were detected in study groups (p < 0.05) and recovered cardiac prolidase levels were obtained in groups II and III (p < 0.05). CONCLUSION: These findings indicate that ginseng extracts may have a potential beneficial effect in I/R injury. However, more comprehensive studies are required to clarify the hypothetical cardiac, renal and systemic protective effects in reperfusion-induced oxidative damage.

Investigation of possible prophylactic, renoprotective, and cardioprotective effects of thromboprophylactic drugs against ischemia-reperfusion injury.

The aim of this study was to investigate whether anticoagulant and antiaggregant agents have protective effects against oxidative damage induced by peripheral ischemia-reperfusion (I/R). Groups were created as follows: control group, I/R group (sham group), I/R plus acetylsalicylic acid (Group I), I/R+clopidogrel (Group II), I/R+rivaroxaban (Group III), I/R+bemiparin sodium (Group IV), and I/R+enoxaparin sodium (Group V). In Groups I, II, III, IV, and V, drugs were administered daily for 1 week before I/R creation. Peripheral I/R was induced in the I/R groups by clamping the right femoral artery. The rats were sacrificed 1 hour after reperfusion. Nitrogen oxide levels, malondialdehyde (MDA) levels, paraoxonase-1 (PON1) activity, and prolidase activity were evaluated in both cardiac and renal tissues. There was no significant difference in nitrogen oxide levels between the groups. However, cardiac and renal MDA were significantly higher and PON1 activity was markedly lower in the I/R groups compared with the control group (p<0.05). Although elevated prolidase activity was detected in both the cardiac and renal tissue of the I/R groups, only the sham group and Group V had significantly higher renal prolidase activity (p<0.05). Group V had significantly higher cardiac MDA, PON1, prolidase levels, and renal prolidase activity compared with the sham group (p<0.05). Significant improvement in renal MDA levels was only observed in Group III, and marked improvement was observed in the cardiac MDA levels of Group II when compared with the sham group (p<0.05). Thromboprophylactic agents appear to provide partial or prominent protection against I/R injury.

Imperatorin is a mechanism-based inactivator of CYP2B6.

Imperatorin (IMP) is the major active ingredient in many common medicinal herbs. We examined the irreversible inhibitory effect of IMP on CYP2B6. IMP produced a time- and concentration-dependent inactivation of CYP2B6. About 70% of activity of CYP2B6 was suppressed after its incubation with 1.5 µM IMP for 9 minutes. KI and kinact were found to be 0.498 µM and 0.079 min(-1), respectively. The loss of CYP2B6 activity required the presence of NADPH. Glutathione and catalase/superoxide dismutase showed little protection against the IMP-induced enzyme inactivation. Ticlopidine, a substrate of CYP2B6, showed protection of the enzyme against the inactivation induced by IMP. The estimated partition ratio of the inactivation was approximately 4. Additionally, a γ-ketoenal intermediate was identified in microsomal incubations with IMP. CYP1A2, CYP2A6, CYP2B6, CYP2D6, CYP2E1, CYP3A4, and CYP3A5 were found to be involved in bioactivation of IMP. In conclusion, IMP is a mechanism-based inactivator of CYP2B6. The formation of γ-ketoenal intermediate may account for the enzyme inactivation.

Antithrombotic activity of a new P2Y1 receptor antagonist, substance Sbt-119, on experimental models of thromboses in rats.

Antithrombotic properties of a new P2Y1 receptor antagonist N-[(1-morpholinopropyl-amino)- carbonyl-2-(1-ethyl-1H-indole-3-yl)-vinyl]-4-methylphenyl-amide hydrochloride, substance Sbt-119, and reference drug ticlopidine were studied on experimental models of arterial and systemic thromboses. Substance Sbt-119 was 39.9% (p<0.05) more potent than ticlopidine in producing the antithrombotic effect. Moreover, substance Sbt-119 was shown to increase the survival rate of animals after systemic treatment with ADP (by 20%, p<0.0001). This substance decreased the number of mural thrombi and reduced the severity of hemodynamics disturbances in the organs during systemic thrombosis.

A randomized controlled trial of adjunctive Bunchang Naoxintong Capsule (步长脑心通胶囊) versus maintenance dose clopidogrel in patients with CYP2C19*2 polymorphism.

OBJECTIVE: To determine the impact of adjunctive Buchang Naoxintong Capsule (, NXT) on dual antiplatelet therapy in patients with cytochrome P450 2C19*2 (CYP2C19*2) polymorphism undergoing percutaneous coronary intervention (PCI). METHODS: Ninety patients with CYP2C19*2 polymorphism were enrolled, and their genotypes were confirmed by polymerase chain reaction (PCR). The patients were randomly assigned to receive either adjunctive NXT (triple group, 45 cases) or dual antiplatelet therapy (dual group, 45 cases) using a computer-generated randomization sequence and sealed envelopes. Platelet function was assessed at baseline and 7 days after treatment with conventional aggregometry. Subsequent major adverse cardiovascular events (MACE, including sudden cardiac arrest and acute coronary syndrome) were recorded during a 12-month follow-up. RESULTS: Baseline platelet function measurements were similar in both groups. After 7 days, percent inhibitions of maximum platelet aggregation and late platelet aggregation were significantly greater in the triple versus dual group (42.3%±16.0% vs. 20.8%±15.2%, P<0.01, and 54.7%±18.3% vs. 21.5%±29.2%, P<0.01, respectively). During the 12-month follow-up, the rate of subsequent MACE (6/45) was significantly lower in the triple group compared with the dual group (14/45; P<0.05). CONCLUSION: Adjunctive NXT to maintenance dose clopidogrel (75 g) could enhance the antiplatelet effect and decrease subsequent MACE in patients with the CYP2C19*2 polymorphism undergoing PCI.

Salvianolic acid B inhibits platelets as a P2Y12 antagonist and PDE inhibitor: evidence from clinic to laboratory.

Salviae miltiorrhiza (Danshen) has been used for thousands of years in China and some other Asian countries to treat atherothrombotic diseases. Salvianolate which consists of three water-soluble ingredients purified from Salviae miltiorrhiza, has been approved by Chinese SFDA to treat coronary artery disease. So far, there is no evidence clearly showing the clinical efficiency of salvianolate and the underlying mechanism. This study is to evaluate the effects of salvianolate on platelets in patients with acute coronary syndrome and explore the underlying mechanism. We evaluated the effects of salvianolate on platelets in patients with acute coronary syndrome by measuring ADP-induced PAC-1 binding and P-selectin expression on platelets. Salvianolate significantly potentiated the antiplatelet effects of standard dual antiplatelet therapy. We also investigated the antiplatelet effects of salvianolatic acid B (Sal-B), the major component which composes 85% of salvianolate. Sal-B inhibits human platelet activation induced by multiple agonists in vitro by inhibiting phosphodiesterase (PDE) and antagonizing P2Y12 receptor. For the first time, we show the antiplatelet efficiency of salvianolate in ACS patients undergoing treatment with clopidogrel plus aspirin, and demonstrate that Sal-B, the major component of salvianolate inhibits human platelet activation via PDE inhibition and P2Y12 antagonism which may account for the clinical antiplatelet effects of salvianolate. Our results suggest that Sal-B may substitute salvianolate for clinical use.

Anticoagulation and antiplatelet therapy in acute coronary syndromes.

Antiplatelet and anticoagulant drugs are the mainstay of treatment of acute coronary syndrome (ACS). The last 30 years have seen the development of various agents, a deeper understanding of the pathobiology of this disease, and an evolution in its treatment. We review the role of contemporary agents in ACS and highlight key clinical trials of these agents.

Study of pharmacodynamic interaction of Phyllanthus emblica extract with clopidogrel and ecosprin in patients with type II diabetes mellitus.

BACKGROUND: Diabetes mellitus is associated with oxidative stress which impairs the platelet function. Phyllanthus emblica extract a rich source of vitamin C plays an important role in scavenging free radicals. The effect of vitamin C on platelet aggregation in healthy and coronary artery disease patients has been demonstrated. The present study attempts to study the pharmacodynamic interactions of P. emblica extract with clopidogrel and ecosprin. MATERIALS AND METHODS: This was a randomized open label crossover study of 10 type II diabetic patients. The dosage schedules were either single dose of 500 mg P. emblica extract or 75 mg clopidogrel or 75 mg ecosprin or 500 mg P. emblica+75 mg clopidogrel or 500 mg P. emblica+75 mg ecosprin. After single dose study and washout period, patients received either 500 mg P. emblica extract twice daily or 75 mg clopidogrel or 75 mg ecosprin once daily or combinations for 10 days. Platelet aggregation was measured at baseline and at 4h of treatment after single and multiple dose study along with recording of bleeding and clotting time. RESULTS: After single and multiple dose administration of the three treatments and with combinations there was statistically significant decrease of platelet aggregation compared to baseline. Further, the mean percent inhibition of platelet aggregation was significant, when compared between single and multiple doses of P. emblica. The bleeding and clotting time was prolonged with single and multiple dose administration of all treatments compared to baseline. All treatments were well tolerated. CONCLUSION: P. emblica extract demonstrated significant antiplatelet activity with both single and multiple dose administration.

Effects of ex vivo platelet supplementation on platelet aggregability in blood samples from patients treated with acetylsalicylic acid, clopidogrel, or ticagrelor.

BACKGROUND: Transfusion of platelet concentrate is often used to treat bleeding in patients on platelet inhibitors, but little is known about its efficacy between different inhibitors. We assessed the effect of ex vivo platelet supplementation on platelet aggregability in blood samples from patients treated with acetylsalicylic acid (ASA), clopidogrel, or ticagrelor. METHODS: Platelet aggregability was investigated with multiple electrode aggregometry with adenosine diphosphate (ADP), arachidonic acid (to assess ASA-dependent aggregability), and thrombin receptor activating peptide-6 (TRAP) as activators in whole-blood samples from patients treated with ASA (n=10), ASA+clopidogrel (n=15), or ASA+ticagrelor (n=15), and from healthy controls (n=10). Aggregability was measured before and after supplementation of AB0-compatible fresh apheresis platelets (+46, +92, and +138×10(9) litre(-1)). RESULTS: Both ASA-dependent and ADP-dependent aggregability improved in a dose-dependent fashion after platelet supplementation. ASA-dependent aggregability was completely restored in all patient groups, but there was only a small improvement in ADP-dependent aggregability in patients on dual antiplatelet therapy. There was less effect of platelet supplementation on ADP- and ASA-dependent aggregability in ticagrelor-treated patients than in clopidogrel-treated patients [3.9 (95% confidence interval 1.6-6.3) vs 9.0 (5.2-12.8) AU×min (P=0.021) and 48 (36-59) vs 69 (60-78) AU×min (P=0.004), respectively, at the highest platelet dose]. CONCLUSIONS: Platelet supplementation improved platelet aggregability independently of antiplatelet therapy. The effect on ADP-dependent platelet inhibition was limited however. Reduced effect of platelet transfusion is more likely within 2 h of drug intake in patients treated with ASA+ticagrelor compared with ASA+clopidogrel.

Antiplatelet resistance in outpatients with monitored adherence.

Antiplatelet resistance with aspirin and clopidogrel has been associated with clinical, cellular and pharmacogenetic factors; and non-adherence has been considered as a major contributor to resistance in outpatients. We aimed at assessing factors to resistance when adherence to the antiplatelet drugs and all other oral solid drugs was controlled for. In a pilot study, we tested arachidonic acid and/or ADP-induced in vitro platelet aggregation of 82 outpatients with chronic aspirin and/or clopidogrel treatment before and after a one-week period of measuring the patient's adherence with the polymedication electronic monitoring system (POEMS). Resistance was found in 20% (aspirin; n = 69) and 25% (clopidogrel; n = 32) of the patients after monitored adherence. Mean platelet aggregation was not (aspirin) or non-significantly (clopidogrel) lowered when compared to baseline. Diabetes mellitus and inflammation were consistently associated with resistance to both drugs, but CYP2C19 polymorphisms could not be confirmed as predictors of clopidogrel response. Electronically compiled multidrug dosing histories allowed the concomitant intake of high-dose lipophilic statins to be identified as a risk factor of impaired response to clopidogrel and revealed that exposure to further potential drug-drug interactions (DDIs) was too low for analysis. Multidrug adherence monitoring allowed thus dismissing non-adherence as a major contributor to resistance and inter-individual response variability in an outpatient setting. Additionally, it allowed analysing the impact of DDIs according to the actual exposure to the potentially interfering drugs. Further studies based on this methodology are essential to prevent misleading results due to incomplete adherence and gain additional insight into the impact of timing adherence on antiplatelet drug response.

[Synergistic action of Compound Danshen Dripping Pill (CDDP) on Clopidogrel Bisulfate (CPG) counteracting platelet aggregation].

OBJECTIVE: To study the synergistic action of Compound Danshen Dripping Pill (CDDP) on Clopidogrel Bisulfate (CPG) counteracting platelet aggregation. METHODS: 40 Sprague-Dawley (SD) rats were randomized into four groups: normal control group (CMC-Na), CPG alone group (30 mg/kg), CDDP alone group (324 mg/kg), co-administration group (CPG 30 mg/kg and CDDP 324 mg/kg). The rats received gastric infusion of corresponding drugs for 21 continuous days. Blood sample of SD rats were collected by puncture of the abdominal artery for the determination of coagulation parameters such as prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB) concentration and thrombin time (TT) in each group. Another 40 SD rats were used for the observation of inhibitory effect on the thrombosis in arteriovenous shunt. Finally, homology modeling and molecular docking were employed to simulate their interaction between the P2Y purinoceptor 12 (P2Y12) target and bioactive compounds contained in CDDP. RESULTS: The bleeding time of coagulation parameters was prolonged, the thrombosis in arteriovenous shunt was inhibited in the medication group. The above effect was much better in the combination group. The molecular docking showed that bioactive compounds contained in CDDP was able to inhibit target P2Y12. CONCLUSION: CDDP can enhance the effect of CPG on inhibiting platelet aggregation.

[Effect of Clopidogrel on Pharmacokinetic of Fufang Danshen Dripping Pill (FDDP)].

OBJECTIVE: To investigate the effect of clopidogrel on the pharmacokinetic of Fufang Danshen Dripping Pill (FDDP); METHODS: 20 SD rats were randomly divided into two group,which were intrinsically administrated FDDP(324 mg/kg) alone and combination of FDDP(324 mg/kg) and clopidogrel(30 mg/kg) respectively for 21 days. The ginsenoside Rg, from FDDP was determined by HPLC and its pharmacokinetic parameter were finally compared. RESULTS: The value of Cmax and AUC0-∞ of ginsenoside Rg, were increased from 1.97 ± 0.44 mg/L and 8.44 ± 2.64 mg/L · h to 2.48 ± 0.63 mg/L and 14.38 ± 5.72 mg/L · h respectively. CONCLUSION: Long term with clopidogrel has effect on the pharmacokinetic character of Rg, from FDDP, this research may provides theoretical support for the FDDP-clopidogrel combination treatment in clinical.

The effect of fibrin clot inhibitors on the immunomodulatory efficacy of Bacillus Calmette-Guérin therapy for non-muscle-invasive bladder cancer.

OBJECTIVE: To determine if there is a difference in clinical outcomes among non-muscle-invasive bladder cancer patients taking fibrin clot-inhibiting (FCI) medications (aspirin, clopidogrel, or warfarin) while receiving Bacillus Calmette-Guérin (BCG) therapy compared with their counterparts not taking anticoagulation. MATERIALS AND METHODS: Our Investigational Review Board-approved database was queried for patients who received an induction course of BCG from 2001 to 2011. The analysis included 224 patients with a minimum of 3 months of follow-up. Recurrence-free survival (RFS), cystectomy-free survival, overall survival, and disease-specific survival were analyzed using the Kaplan-Meier method stratified by FCI status. Logistic regression was used to predict the initial response rate to BCG and progression by FCI status. RESULTS: Of the 224 patients analyzed, 68, 19, and 23 patients were taking aspirin, clopidogrel and warfarin, respectively, at BCG induction. No specific FCI was associated with differences in cystectomy-free survival, overall survival, disease-specific survival, or the likelihood of progression at recurrence. Neither warfarin nor clopidogrel affected RFS. Patients taking aspirin trended toward increased RFS, although this was not statistically significant (P = .058). Multivariate analysis showed aspirin use was associated with an increased initial response to BCG (odds ratio, 2.41; P = .031) CONCLUSION: Contrary to the postulated inhibitory molecular effect of FCI on BCG-binding activity, this study did not substantiate a significant impact on BCG efficacy of the concomitant use of these medications during BCG induction. The observation that aspirin use potentiates an increased initial response to BCG may warrant further analysis.

High-dose aspirin in dogs increases vascular resistance with limited additional anti-platelet effect when combined with potent P2Y12 inhibition.

INTRODUCTION: With the arrival of the potent P2Y12 antagonists, ticagrelor and prasugrel, the need for co-treatment with aspirin in acute coronary syndromes must be re-examined. This study assessed whether high-dose aspirin: a) provides additional anti-platelet efficacy, assessed in vivo and ex vivo, when combined with P2Y12 inhibition; and/or b) has a negative effect on vascular function. MATERIALS AND METHODS: Using an anaesthetized dog model of thrombosis, the effects of aspirin (50mg/kg) in addition to clopidogrel and ticagrelor were evaluated at two levels of P2Y12 inhibition, maximal (≥96%) and sub-maximal (~80%), as assessed by ex vivo ADP-induced whole blood impedence aggregometry. RESULTS: In the absence of aspirin, maximal and sub-maximal P2Y12 inhibition inhibited arachidonic acid-induced platelet aggregation by approximately 80% and 24%, respectively, without affecting platelet TXA2 formation. During maximal P2Y12 inhibition, aspirin provided less additional inhibition of ex vivo arachidonic acid- and collagen-induced platelet aggregation, as compared with sub-maximal P2Y12 inhibition, without additional anti-thrombotic effect in vivo. Aspirin significantly decreased in vivo PGI2 production (27%) and increased vascular resistance (16%), independently of P2Y12 antagonism. CONCLUSION: In the dog, P2Y12 antagonists inhibit TXA2-mediated platelet-aggregation independently of aspirin. Aspirin provides less additional anti-platelet effects during maximal compared with sub-maximal P2Y12 inhibition but increases vascular resistance.