Circulation, Vol 72, 698-701, Copyright © 1985 by American Heart Association
AJ Marcus, LB Safier, HL Ullman, MJ Broekman, N Islam, TD Oglesby, RR Gorman and JW Ward
Accumulating experimental and clinical evidence indicates that a time for
reappraisal of therapeutic modalities designed to inhibit the eicosanoid
pathway as it may affect vascular disease may be approaching. Pharmacologic
agents originally used were chosen because they were capable of suppressing
platelet functions such as aggregation, release, and adhesion. The goals of
clinical trials were to evaluate medications that would prevent or reduce
platelet accumulation in critically located blood vessels of the heart,
brain, and extremities and on vascular prostheses. Evaluation of results of
therapeutic trials has been difficult and this is superimposed on less-
than-complete knowledge of the basic pharmacology of the drugs that have
been used. Participation of neutrophils and possibly macrophages in the
thrombotic process is now well recognized on morphologic grounds. Because
different cell types such as platelets, neutrophils, and endothelial cells
have been shown to interact biochemically by sharing precursors and
intermediates of the eicosanoid pathway, the pharmacologic approach to
inhibition of vascular disease may require reevaluation. Neutrophils appear
to lack a cyclooxygenase pathway but serve as a source of the lipoxygenase
product leukotriene B4 (LTB4). Actions of LTB4 include neutrophil
aggregation, adhesion of neutrophils to endothelial cells, chemotaxis,
chemokinesis, and plasma exudation. We have demonstrated in vitro that
released free arachidonic acid from aspirin-treated platelets can serve as
a source of neutrophil LTB4. Leukotrienes C4, D4, and E4 are agonists for
various functions of vascular endothelium and smooth muscle. Most
pharmacologic agents used in the treatment of vascular diseases inhibit the
cyclooxygenase pathway.(ABSTRACT TRUNCATED AT 250 WORDS)
ARTICLES
Inhibition of platelet function in thrombosis
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