Platelet-derived microparticles promote phagocytosis of oxidized low-density lipoprotein by macrophages, potentially enhancing foam cell formation.

Background: The interaction between platelets and macrophages plays an important role in the development and progression of atherosclerosis (AS). This study aimed to investigate the role of platelet microparticles (PMPs) in the development of foam cells. Methods: PMPs are generated by activating platelets with thrombin and separated by ultracentrifugation. The macrophages were treated with PMPs, the phagocytosis of oxidized low-density lipoprotein (Ox-LDL) and formation of foam cells were evaluated by flow cytometry and confocal microscopy, respectively, and the inflammatory factors cytokines in the supernatant were detected by ELISA. Results: PMPs significantly increase the phagocytosis of Ox-LDL and elevated foam cell formation of macrophages. IL-1 beta content in the supernatant of macrophages peaked around 2-4 h and declined to normal level after 6-8 h; IL-6 content peaked at 4 h and then decreased to normal level. TNF-alpha content peaked at 2-4 h. Conclusions: The microparticles from activated platelets can increase the phagocytosis of Ox-LDL and the production of inflammatory cytokines by macrophages, which is related to the development of AS.