Lipid Characterisation of Plasma Microparticles in a Large Population of Healthy Donors

Extracellular vesicles (EVs) are membrane structures containing numerous mediators categorised according to their size and mode of production. Among them, microparticles (MPs) are EVs between 100 nm and 1 μm in size that are produced by budding at the plasma membrane of different cell types following different mechanisms of cell activation or death. MPs include a large pool of bioactive molecules, such as lipids, proteins or nucleic acids. This makes them important mediators of intercellular communication, increasingly recognised for their role in various biological processes such as inflammation, coagulation, immune response and tumour progression. Their ability to transmit molecular signals between cells may have implications for disease pathogenesis and cellular interactions in pathological microenvironments. These MPs therefore appear to be an innovative biomarker, potentially useful in the early management of disease, both in terms of diagnosis and as a therapeutic target. The main techniques used to analyse these MPs include flow cytometry, which enables surface markers to be quantified and determined, and electron microscopy, which provides a direct view of their morphology and structure. Molecular biology, such as the quantitative PCR technique, is also an approach used by several teams, notably to search for RNA or DNA fragments involved in various biological processes. However, few studies have focused on the lipid composition of these MPs. Since MPs are membrane vesicles, they are a major lipid reservoir. In addition, lipids represent a significant population of molecules with extensive properties, whether in inflammation, cell proliferation, energy metabolism, etc. The aim of this project is to develop a reliable and robust method for analysing plasma MP concentration, phenotype and lipid composition in a population of healthy volunteers. These parameters will subsequently provide a comparator for studying MPs in populations of patients suffering from cardiovascular and/or inflammatory diseases.