Rethinking Platelet Identity from an Extracellular Vesicle-Centric View: A Proof-of-Concept Study

The long-standing ambiguity surrounding whether platelets are cells or particles has hindered a unified understanding of their biology. In this study, we characterized the morphology of platelet-like particles (PLPs) using nanoparticle tracking analysis, transmission electron microscopy, and immunofluorescence. Notably, we observed that platelets can be endocytosed by living cells. We also indicate that platelets express the canonical extracellular vesicles (EVs) markers CD9, CD63, CD81, and TSG101. Our results demonstrate that platelets share six key similarities with EVs--in size, morphology, surface markers, function, biogenesis, and mode of action--leading us to propose a novel classification. Our findings suggest that platelets fulfill the current minimal criteria for EVs, raising the possibility that they could be conceptually viewed as a specialized EVs subset rather than conventional blood cells. Adopting this EVs-centric perspective could broaden the current conceptual framework for EVs and offer an alternative lens for interpreting platelet functions, which may in turn help guide future translational research and clinical exploration.