Circulating MicroRNA Levels Indicate Platelet and Leukocyte Activation in Endotoxemia Despite Platelet P2Y12 Inhibition.

Aitana Braza-Boïls,Heather M Judge,Mark R Thomas,Robert F Storey,Temo Barwari,Ian Sabroe,Manuel Mayr,Abhishek Joshi,Raimund Pechlaner,Clemens Gutmann,Manu Shankar-Hari,Ramzi A Ajjan

doi:10.3390/ijms21082897

Abstract

There is evidence for the effects of platelet inhibition on innate immune activation. Circulating microRNAs (miRNAs) have been implicated as markers of platelet and leukocyte activation. In the present study, we assessed the effects of P2Y12 inhibitors on platelet and leukocyte miRNAs during endotoxemia. Healthy volunteers were randomly assigned to receive oral ticagrelor (n = 10), clopidogrel (n = 8) or no drug (n = 8) for one week, followed by an intravenous bolus of 2 ng/kg endotoxin. Serum was collected at baseline, after one week of antiplatelet treatment and 6 and 24 h after endotoxin administration. MiRNAs were screened using LNA-based qPCR, followed by TaqMan-qPCR validation of candidates. Clinical validation was performed in 41 sepsis patients. Platelet-enriched miR-197, miR-223 and miR-223* were decreased in volunteers following antiplatelet therapy. Endotoxin increased platelet miRNAs, whilst the opposite effect was seen for leukocyte-enriched miR-150. Neither of these endotoxin-mediated effects were altered by P2Y12 inhibitors. Sepsis patients with fatal outcomes (n = 12) had reduced miR-150 levels compared with survivors (n = 29). In conclusion, we show that miR-150 is downregulated in experimental endotoxemia and can predict survival in sepsis but is unaffected by P2Y12 inhibition. While P2Y12 inhibition reduces platelet-associated miRNAs in healthy volunteers, it fails to attenuate the response of platelet miRNAs to endotoxemia.

Highlights

Sepsis affects around 31.5 million people per year globally, of which approximately 5.3 million die [1]
Sepsis is characterized by an excessive immune response to infection that leads to organ dysfunction [3]
The mechanisms are not fully understood, increased platelet reactivity might contribute to the 18-fold risk increase of myocardial infarction or stroke within 30 days of bacteremia [5]

Summary

Introduction

Sepsis affects around 31.5 million people per year globally, of which approximately 5.3 million die [1]. As a consequence of the systemic presence of inflammatory stimuli, platelets are activated on a large scale. This further aggravates septic coagulation and inflammatory reactions, potentially leading to disseminated intravascular coagulation [4]. The question whether (and which) platelet inhibitors are able to attenuate this detrimental process is highly relevant. This has been addressed in pre-clinical sepsis models as well as a few, mostly retrospective clinical studies. Other studies did not confirm benefits on severity and outcome, and the hypercoagulable state in sepsis remains difficult to manage [12,13,14]

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