0000000000008425
AUTHOR
Thomas M. Mcintyre
Vitamin C blocks inflammatory platelet-activating factor mimetics created by cigarette smoking.
Cigarette smoking within minutes induces leukocyte adhesion to the vascular wall and formation of intravascular leukocyte-platelet aggregates. We find this is inhibited by platelet-activating factor (PAF) receptor antagonists, and correlates with the accumulation of PAF-like mediators in the blood of cigarette smoke-exposed hamsters. These mediators were PAF-like lipids, formed by nonenzymatic oxidative modification of existing phospholipids, that were distinct from biosynthetic PAF. These PAF-like lipids induced isolated human monocytes and platelets to aggregate, which greatly increased their secretion of IL-8 and macrophage inflammatory protein-1alpha. Both events were blocked by a PAF r…
Platelet Signal-Dependent Protein Synthesis
Our understanding of platelet functions has been in evolution since their discovery. Blood platelets were initially observed in the middle of the 19th century by many investigators including Zimmerman in 1860, Schultze in 1865, Osler in 1874, and Hayem in 1878 (1). Studies by Bizzozero (2,3) were the first to recognize the adhesive qualities of platelets, their participation in thrombosis and leukocyte recruitment, and their role in blood coagulation. These monumental findings, which have withstood the test of time, have expanded at a remarkable rate and continue to be the primary focus of investigative research in the platelet arena (4).