Vasodilator-stimulated phosphoprotein (VASP) is not a major mediator of platelet aggregation, thrombogenesis, haemostasis, and antiplatelet effect of prasugrel in rats

Serum-integrated omics reveal the host response landscape for severe pediatric community-acquired pneumonia

OBJECTIVE

Community-acquired pneumonia (CAP) is the primary cause of death for children under five years of age globally. Hence, it is essential to investigate new early biomarkers and potential mechanisms involved in disease severity.

METHODS

Proteomics combined with metabolomics was performed to identify biomarkers suitable for early diagnosis of severe CAP. In the training cohort, proteomics and metabolomics were performed on serum samples obtained from 20 severe CAPs (S-CAPs), 15 non-severe CAPs (NS-CAPs) and 15 healthy controls (CONs). In the verification cohort, selected biomarkers and their combinations were validated using ELISA and metabolomics in an independent cohort of 129 subjects. Finally, a combined proteomics and metabolomics analysis was performed to understand the major pathological features and reasons for severity of CAP.

RESULTS

The proteomic and metabolic signature was markedly different between S-CAPs, NS-CAPs and CONs. A new serum biomarker panel including 2 proteins [C-reactive protein (CRP), lipopolysaccharide (LBP)] and 3 metabolites [Fasciculol C, PE (14:0/16:1(19Z)), PS (20:0/22:6(4Z, 7Z, 10Z, 13Z, 16Z, 19Z))] was developed to identify CAP and to distinguish severe pneumonia. Pathway analysis of changes revealed activation of the cell death pathway, a dysregulated complement system, coagulation cascade and platelet function, and the inflammatory responses as contributors to tissue damage in children with CAP. Additionally, activation of glycolysis and higher levels of nucleotides led to imbalanced deoxyribonucleotide pools contributing to the development of severe CAP. Finally, dysregulated lipid metabolism was also identified as a potential pathological mechanism for severe progression of CAP.

CONCLUSION

The integrated analysis of the proteome and metabolome might open up new ways in diagnosing and uncovering the complexity of severity of CAP.

The Function and Regulation of Platelet P2Y12 Receptor

In addition to the key role in hemostasis and thrombosis, platelets have also been wildly acknowledged as immune regulatory cells and involving in the pathogenesis of inflammation-related diseases. Since purine receptor P2Y12 plays a crucial role in platelet activation, P2Y12 antagonists such as clopidogrel, prasugrel, and ticagrelor have been widely used in cardiovascular diseases worldwide in recent decades due to their potent antiplatelet and antithrombotic effects. Meanwhile, the role of P2Y12 in inflammatory diseases has also been extensively studied. Relatively, there are few studies on the regulation of P2Y12. This review first summarizes the various roles of P2Y12 in the process of platelet activation, as well as downstream effects and signaling pathways; then introduces the effects of P2Y12 in inflammatory diseases such as sepsis, atherosclerosis, cancer, autoimmune diseases, and asthma; and finally reviews the current researches on P2Y12 regulation.

Platelet reactivity testing in peripheral artery disease

DISCLAIMER

In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

Oral antiplatelet therapy is routinely used to prevent adverse cardiovascular events in patients with peripheral artery disease (PAD). Several laboratory tests are available to quantify the degree of platelet inhibition following antiplatelet therapy. This article aims to provide a review of the literature surrounding platelet functional testing in patients with PAD receiving oral P2Y12 inhibitors and to offer guidance to clinicians for the use and interpretation of these tests.

SUMMARY

A literature search of PubMed and the Web of Science Core Collection database was conducted. All studies that performed platelet function testing and reported clinical outcomes in patients with PAD were included. Evaluation of the data suggests that, among the available testing strategies, the VerifyNow platelet reactivity unit (PRU) test is the most widely used. Despite numerous investigations attempting to define a laboratory threshold indicating suboptimal response to antiplatelet therapy, controversy exists about which PRU value best correlates with cardiovascular outcomes (ie, mortality, stent thrombosis, etc). In the PAD literature, the most commonly used PRU thresholds are 208 or higher and 235 or higher. Nonetheless, adjusting antiplatelet regimens based on suboptimal P2Y12 reactivity values has yet to be proven useful in reducing the incidence of adverse cardiovascular outcomes. This review examines platelet function testing in patients with PAD and discusses the interpretation and application of these tests when monitoring the safety and efficacy of P2Y12 inhibitors.

CONCLUSION

Although platelet functional tests may be simple to use, clinical trials thus far have failed to show benefit from therapy adjustments based on test results. Clinicians should be cautioned against relying on this test result alone and should instead consider a combination of laboratory, clinical, and patient-specific factors when adjusting P2Y12 inhibitor therapy in clinical practice.

Pharmacokinetic, pharmacodynamic, and pharmacogenetic assays to monitor clopidogrel therapy

Clopidogrel is the most common and widely used antiplatelet agent for patients with coronary artery disease following confirmation by electrocardiographic studies. The nonresponsiveness of patients to clopidogrel and the possibility of testing for clopidogrel resistance by platelet function assays (PFA) are contentious issues. Light transmission aggregometry (LTA) is considered as the gold standard test among all PFA. In this review, the most commonly used PFA used for monitoring the effect of clopidogrel, LTA, vasodilator-stimulated phosphoprotein assay phosphorylation, rotational thromboelastometry (ROTEM) delta and ROTEM platelet, thromboelastography, PFA-100, VerifyNow P2Y12 assay, Multiplate analyzer, Plateletworks assay and pharmacogenetic studies, are comparatively discussed including their principles of action, advantages, and disadvantages. VerifyNow P2Y12 assay can be accepted as the ideal point of care test out of the discussed assays. However, modified assays are required which could overcome the limitations associated with currently available assays.