title: Vitamin C blocks inflammatory platelet-activating factor mimetics created by cigarette smoking.
abstract: 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 receptor antagonist. Similarly, blocking the PAF receptor in vivo blocked smoke-induced leukocyte aggregation and pavementing along the vascular wall. Dietary supplementation with the antioxidant vitamin C prevented the accumulation of PAF-like lipids, and it prevented cigarette smoke-induced leukocyte adhesion to the vascular wall and formation of leukocyte-platelet aggregates. This is the first in vivo demonstration of inflammatory phospholipid oxidation products and it suggests a molecular mechanism coupling cigarette smoke with rapid inflammatory changes. Inhibition of PAF-like lipid formation and their intravascular sequela by vitamin C suggests a simple dietary means to reduce smoking-related cardiovascular disease.
authors.affiliation: Institute for Pathology, Johannes Gutenberg University, Mainz, Germany.
authors.forename: H A
authors.initials: HA
authors.lastname: Lehr
authors.forename: A S
authors.initials: AS
authors.lastname: Weyrich
authors.forename: R K
authors.initials: RK
authors.lastname: Saetzler
authors.forename: A
authors.initials: A
authors.lastname: Jurek
authors.forename: K E
authors.initials: KE
authors.lastname: Arfors
authors.forename: G A
authors.initials: GA
authors.lastname: Zimmerman
authors.forename: S M
authors.initials: SM
authors.lastname: Prescott
authors.forename: T M
authors.initials: TM
authors.lastname: McIntyre
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology*; D001381:Azepines / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D002448:Cell Adhesion; D002449:Cell Aggregation; D054407:Chemokine CCL4; D006224:Cricetinae; D006801:Humans; D016209:Interleukin-8 / Q000097:blood; D019402:Macrophage Inflammatory Proteins / Q000097:blood; D009000:Monocytes / Q000187:drug effects / Q000502:physiology*; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D010972:Platelet Activating Factor / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology*; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D010980:Platelet Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000502:physiology; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D012016:Reference Values; D012907:Smoking / Q000097:blood*; D013997:Time Factors; D014230:Triazoles / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D001381:Azepines; D054407:Chemokine CCL4; D016209:Interleukin-8; D019402:Macrophage Inflammatory Proteins; D010972:Platelet Activating Factor; D010975:Platelet Aggregation Inhibitors; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D014230:Triazoles; C039351:platelet activating factor receptor; C052518:WEB 2086; D001205:Ascorbic Acid