Platelets in sepsis.

Platelets are circulating blood cells that will normally not interact with the intact vessel wall but that may swiftly respond to vascular disruption by adhering to subendothelial structures, followed by interaction with each other, thereby forming a platelet aggregate. The activated platelet (phospholipid) membrane may form a suitable surface on which further coagulation activation may occur. These processes are part of the first line of defence of the body against bleeding but may also contribute to pathological thrombus formation in vascular disease, such as thrombus formation on top of a ruptured atherosclerotic plaque. In case of systemic inflammatory syndromes, such as the response to sepsis, disseminated intravascular platelet activation may occur, which will contribute to microvascular failure and thereby play a role in the development of organ dysfunction. In addition, in this situation platelets may be directly involved in the inflammatory response by releasing inflammatory mediators and growth factors.