Inflammation and monocyte-platelet aggregates
Research type
Research Study
Full title
Effect of anti-platelet drugs on the level of circulating monocyte-platelet aggregates and on monocyte phenotype in acute inflammation
IRAS ID
70786
Contact name
Albert Ferro
Contact email
Research summary
Monocyte-platelet aggregates (MPA) are small particles formed by two different cell types circulating in the blood (monocytes and platelets) which stick together as a consequence of platelet activation. Accordingly, MPA level in the blood provides a sensitive index of platelet activity, and increases in patients with acute thrombotic events, such as heart attack or stroke, as well as in subjects with underlying cardiovascular risk factors.
We recently observed that circulating MPA also increase in healthy subjects receiving influenza vaccine, as a consequence of the inflammatory response induced by immunisation, and that increased MPA in turn causes monocyte activation. This effect is short-term in subjects undergoing immunisation, but in the presence of chronic sustained platelet activation, such as that observed in patients with cardiovascular disease or cardiovascular risk factors, this may lead to atherosclerosis progression by favouring monocyte vascular infiltration. Indeed, published evidence, including a recent clinical study we have conducted in subjects with silent atherosclerosis, has shown that atherosclerosis is associated with acquisition of a pro-inflammatory profile by circulating monocytes.
The current clinical study aims to investigate whether anti-platelet drugs currently used in clinical practice for cardiovascular prophylaxis(aspirin, clopidogrel and ticagrelor) can modify the profile of circulating monocytes by reducing platelet activation. We propose to address this question in an experimental model of mild inflammation, namely that provided by seasonal influenza vaccination in healthy subjects.
Potential participants will be recruited from subjects attending for routine influenza immunisation by the Occupational Health Department at Guy's and St Thomas' NHS Trust. After receiving influenza vaccine, participants will be randomly assigned to receive either aspirin, clopidogrel, ticagrelor or placebo treatment. Measurement of MPA levels and monocyte characterization will be conducted before and 2 days post-immunisation.
This study will shed new light on the potential anti-inflammatory action of different anti-platelet drug therapies.REC name
London - Dulwich Research Ethics Committee
REC reference
13/LO/1664
Date of REC Opinion
19 Dec 2013
REC opinion
Further Information Favourable Opinion