Application of Flow Cytometry in the Studies of Microparticles

Many cell types including leukocytes, platelets and endothelial cells release small membrane fragments called microparticles (MP). MP are shed during cell growth, activation, proliferation, senescence and apoptosis. MP contain proteins (intracellular as well as surface markers), mRNA and miRNA of the cells they have originated from. Based on the release mechanism, size and phenotype, MP are frequently divided into two categories: exosomes and ectosomes called also microvesicles. There is no doubt that the biological significance of MP has been largely overlooked for many years, regarding them as merely cellular fragments or debris. Nowadays, MP are being recognized as an important regulator of cellular interactions under physiological and pathological conditions. MP are present in all body fluids and physiologically serve various functions like blood clotting, enhance cell adhesiveness, increase cell aggregation, etc. They mediate cell-to-cell communication by transferring cell surface receptors, mRNA, and miRNA from the cell of origin to target cells. The growing body of literature regarding the role of MP in many pathologies has recently progressed from describing the association of elevated MP number with disease stage (e.g. cancer, sepsis) through understanding how MP may contribute to thrombosis, preeclampsia and tumor progression, and finally, to using MP as a source of antigens in new forms of vaccines against infectious or malignant diseases.