Adenosine inhibition of adenosine diphosphate and thrombin-induced monocyte-platelet aggregates in cardiac syndrome X

Regional distributions of curcumin and tetrahydrocurcumin in the liver and small intestine of rats when orally co-administered with quercetin and paeoniflorin

Curcumin (CUR), derived from the dietary spice turmeric, is a polyphenolic compound with various biological and pharmacological activities. Tetrahydrocurcumin (THC) is one of the major reductive metabolites of curcumin. A pharmacokinetic study using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for the simultaneous determination of curcumin, THC, quercetin (QR), and paeoniflorin (PF) in rat plasma had been performed. In this study, the regional distributions of curcumin and tetrahydrocurcumin in the liver and the three segments of small intestine (duodenum, jejunum, and ileum) of rats when orally co-administered with quercetin and paeoniflorin were carried out. Drug concentrations were determined using UHPLC-MS/MS. The results showed that curcumin was well distributed in the small intestine, while the distributions of tetrahydrocurcumin in the liver, duodenum, jejunum were similar, but much more abundant in the ileum. When orally co-administered with quercetin and paeoniflorin, the tissue to plasma concentration ratios (K_p values) of curcumin in the three segments of the small intestine were increased, indicating that the presence of quercetin and paeoniflorin increases the distribution of curcumin in these regions. Moreover, the half-life (t_1/2 ) of THC in the liver was significantly prolonged, and the K_p value of THC in the liver was increased and the K_p values in the small intestine were decreased, suggesting that the combination of quercetin and paeoniflorin might suppress the metabolism of curcumin in the small intestine. In brief, the combination had an effect on the distributions of curcumin and tetrahydrocurcumin in the liver and small intestine of rats.

Ischemia and No Obstructive Coronary Artery Disease (INOCA): Developing Evidence-Based Therapies and Research Agenda for the Next Decade

The Cardiovascular Disease in Women Committee of the American College of Cardiology, in conjunction with interested parties (from the National Heart, Lung, and Blood Institute, American Heart Association, and European Society of Cardiology), convened a working group to develop a consensus on the syndrome of myocardial ischemia with no obstructive coronary arteries. In general, these patients have elevated risk for a cardiovascular event (including acute coronary syndrome, heart failure hospitalization, stroke, and repeat cardiovascular procedures) compared with reference subjects and appear to be at higher risk for development of heart failure with preserved ejection fraction. A subgroup of these patients also has coronary microvascular dysfunction and evidence of inflammation. This document provides a summary of findings and recommendations for the development of an integrated approach for identifying and managing patients with ischemia with no obstructive coronary arteries and outlines knowledge gaps in the area. Working group members critically reviewed available literature and current practices for risk assessment and state-of-the-science techniques in multiple areas, with a focus on next steps needed to develop evidence-based therapies. This report presents highlights of this working group review and a summary of suggested research directions to advance this field in the next decade.

Persistent enhanced platelet activation in patients with acute myocardial infarction and coronary microvascular obstruction: clinical implications

About 30% of patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing recanalisation of the infarct-related coronary artery do not achieve valid myocardial reperfusion (no-reflow phenomenon or coronary microvascular obstruction [MVO]). The mechanisms of MVO are incompletely understood. In this study we investigated the role platelet activation in the pathogenesis of coronary MVO in STEMI patients. We enrolled 48 STEMI patients (age 56.2 ± 11 years; 31 men), treated by primary percutaneous coronary intervention (PCI) followed by double anti-platelet treatment, and 20 control patients with stable coronary artery disease (CAD) on single anti-platelet treatment (age 57.5 ± 6 years, 12 men). STEMI patients were divided into two groups: 35 patients with complete myocardial reperfusion (MR) and 13 patients with coronary MVO despite successful PCI. Platelet activation was assessed on admission and at one-month follow-up by measuring platelet receptor expression and monocyte-platelet aggregates (MPAs). Platelet receptor expression, platelet receptor conformational change for fibrinogen binding availability and MPA formation were increased in STEMI patients with MVO compared to both STEMI patients with MR and stable CAD patients, both on admission and at one-month follow-up (p<0.05 for all).Among STEMI patients, platelet activation is greater in those who display coronary MVO, compared to those with MR, after successful PCI, both on admission and one month after STEMI, suggesting that enhanced platelet activation might be involved in the pathogenesis of MVO. The persistence of enhanced platelet activation despite double classical anti-platelet therapy suggests that new anti-platelet strategies should be considered in patients with coronary MVO.

Adenosine release: a potential explanation for the benefits of ticagrelor in the PLATelet inhibition and clinical outcomes trial?

OBJECTIVE

the objective of the study was to hypothesize on the potential mechanism explaining the surprising mortality benefit of ticagrelor in the PLATO trial.

BACKGROUND

in PLATO, the mortality reduction (107 deaths) numerically exceeds the myocardial infarction prevention benefit (89 events), making it a hitherto unmatchable achievement of ticagrelor over active comparator. If confirmed, such an impressive mortality advantage will be critical for the further success of ticagrelor to compensate for its otherwise unfavorable safety profile. In fact, such an impressive survival represents an entirely unexpected benefit, which will serve as a key point in the drug approval process and subsequent use in clinical practice.

METHODS

The potential association of ticagrelor as a promoter of blood adenosine serving as adenosine agonist is assessed.

RESULTS

multiple properties of adenosine, which can be closely matched with both clinical benefits and adverse events after ticagrelor, suggest that this novel pyrimidine is not a pure antiplatelet agent. Unquestionably, ticagrelor potently inhibits platelet activity via established mechanism of P2Y12 receptor blockade, probably chronically increasing blood adenosine levels and ultimately contributing to the vascular outcome benefit observed in PLATO.

CONCLUSIONS

future randomized trials of ticagrelor in acute heart failure, sudden death prevention, and treatment of atrial fibrillation are warranted and will expand our understanding of the potential role of adenosine in the outcome benefit after pyrimidines.