title: Critical roles of platelets in lipopolysaccharide-induced lethality: effects of glycyrrhizin and possible strategy for acute respiratory distress syndrome.
abstract: Within a few minutes of an intravenous injection of a lipopolysaccharide (LPS) into mice, platelets accumulate, largely in the lung. At higher doses, LPS induces rapid shock (within 10 min), leading to death within 1 h. This type of shock differs from so-called endotoxin shock, in which shock signs and death occur several hours or more later. Here, we found that platelet depletion (by a monoclonal anti-platelet antibody) prevented LPS-induced rapid shock, but increased delayed lethality. In Japan, glycyrrhizin (GL), a compound isolated from licorice, is daily and slowly infused intravenously into chronic hepatitis C patients. A single bolus intravenous injection into mice of GL (200 mg/kg or less) shortly before (or simultaneously with) LPS injection reduced the pulmonary platelet accumulation and the severity of the rapid shock, and prevented death in both the early and later periods. GL itself, at 400 mg/kg, produced no detectable abnormalities in the appearance or activity of mice. Intraperitoneal injection of aspirin or dexamethasone had only marginal effects on LPS-induced platelet responses and lethality. These results suggest that platelets play important roles in the development of both the rapid and delayed types of shock induced by LPS. Although the mechanism by which GL suppresses platelet responses and delayed lethality remains to be clarified, GL might provide a strategy for alleviating the acute respiratory distress syndrome seen in sepsis. Our results may also support the proposal by Cinatl et al. [Cinatl J, Morgenstern B, Bauer G, Chandra P, Ravenau H, Doerr HW. Glycyrrhizin, an active component of liquorice roots, and replication of SARS-associated coronavirus. Lancet 2003; 361: 2045-6.] that GL may be an effective drug against severe acute respiratory syndrome.
authors.affiliation: Department of Molecular Regulation, Graduate School of Dentistry, Tohoku University, 4-1 Seiryo-machi, Sendai 980-8575, Japan.
authors.forename: Zhiqian
authors.initials: Z
authors.lastname: Yu
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ohtaki
authors.forename: Kenzou
authors.initials: K
authors.lastname: Kai
authors.forename: Takashi
authors.initials: T
authors.lastname: Sasano
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Shimauchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Yokochi
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Takada
authors.forename: Shunji
authors.initials: S
authors.lastname: Sugawara
authors.forename: Katsuo
authors.initials: K
authors.lastname: Kumagai
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Endo
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001241:Aspirin / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D003907:Dexamethasone / Q000494:pharmacology; D019695:Glycyrrhizic Acid / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008168:Lung / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010976:Platelet Count; D012128:Respiratory Distress Syndrome / Q000188:drug therapy*; D012701:Serotonin / Q000097:blood / Q000378:metabolism; D012772:Shock, Septic / Q000188:drug therapy / Q000209:etiology* / Q000473:pathology
chemical_list: D000911:Antibodies, Monoclonal; D008070:Lipopolysaccharides; D012701:Serotonin; D019695:Glycyrrhizic Acid; D003907:Dexamethasone; D001241:Aspirin