Effects of the second-generation synthetic lipid A analogue E5564 on responses to endotoxin in [corrected] equine whole blood and monocytes.
OBJECTIVE
To evaluate proinflammatory effects of the second-generation synthetic lipid A analogue E5564 on equine whole blood and isolated monocytes and to determine the ability of E5564 to prevent LPS (lipopolysaccharide)-induced procoagulant activity (PCA); tumor necrosis factor (TNF)-alpha production; and mRNA expression of TNF-alpha, interleukin (IL)-1beta, IL-6, and IL-10 by equine monocytes.


METHODS
Venous blood samples obtained from 19 healthy horses.


METHODS
Whole blood and monocytes were incubated with Escherichia coli O111:B4 LPS, E5564, or E5564 plus E coli O111:B4 LPS. Whole blood and cell supernatants were assayed for TNF-alpha, and cell lysates were assayed to determine PCA. Expression of mRNA for TNF-alpha, IL-1beta, IL-6, and IL-10 by monocytes was determined by use of real-time quantitative PCR assay.


RESULTS
Minimal proinflammatory effects were detected in whole blood and monocytes. In addition, E5564 inhibited LPS-induced PCA and TNF-alpha production in a concentration-dependent manner. Furthermore, E5564 significantly inhibited LPS-induced mRNA expression of TNF-alpha, IL-1beta, and IL-10 and decreased LPS-induced expression of IL-6.


CONCLUSIONS
The second-generation synthetic lipid A analogue E5564 lacked agonist activity in equine whole blood and monocytes and was a potent antagonist of enteric LPS. Therefore, E5564 appeared to be the first lipid A analogue that has potential as an effective therapeutic agent in horses with endotoxemia.
Figueiredo
Monica D
MD
Department of Physiology and Pharmacology and Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602-7385, USA.
Moore
James N
JN
Vandenplas
Michel L
ML
Sun
Wan-chun
WC
Murray
Thomas F
TF
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D006736:Horses / Q000097:blood* / Q000276:immunology; D020128:Inhibitory Concentration 50; D016753:Interleukin-10 / Q000096:biosynthesis / Q000235:genetics; D053583:Interleukin-1beta / Q000096:biosynthesis / Q000235:genetics; D015850:Interleukin-6 / Q000096:biosynthesis / Q000235:genetics; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D008050:Lipid A / Q000031:analogs & derivatives* / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics
D000893:Anti-Inflammatory Agents; C404742:E5564; D053583:Interleukin-1beta; D015850:Interleukin-6; D008050:Lipid A; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10