Megakaryocytes from them , and the resultant platelet synthesize many pro-inflammatory and pro - atherosclerotic lesions. These mediators are stored in a platelet granules . Platelet activation induces the release of mediators in the extracellular environment . Resting platelets do not adhere to unstimulated endothelial cells and do not react with them and with the vessel wall . Activation of endothelial cells and / or platelets triggers the inflammation, which causes inter alia atherosclerosis .