Endothelin-stimulated monocyte supernatants enhance neutrophil superoxide production

Document Type

Article

Publication Title

Shock (Augusta, Ga.)

Abstract

Endothelin-1 (ET-1) is a vasoconstrictive peptide released by ischemic/injured endothelium which increases intracellular ionized calcium [Ca2+]i in vascular smooth muscle. Previous work from this lab has shown that ET-1 also increases human peripheral blood monocyte [Ca2+]i, and that 24 h incubation of monocytes with 10(-9) M ET-1 causes production of prostaglandin E2 and interleukin-6. In these studies, ET-1-stimulated monocyte supernatants were evaluated for their effect on neutrophil superoxide production. While ET-1 alone had no direct effect, incubation of neutrophils for 20 min in ET-1-stimulated monocyte supernatants resulted in a 10-fold increase in superoxide production over basal levels, 44% as much superoxide production as induced by peptide N-formyl-methionyl-leucyl-phenylalanine (N = 6, p < .001). Monocyte supernatants were analyzed for interleukin-8 (IL-8 or neutrophil activation protein) content by radioimmunoassay. ET-1-stimulation resulted in production of 54% as much IL-8 as lipopolysaccharide controls (N = 6, p < .001). While a number of monokines can activate neutrophils, IL-8 has been shown to be a potent neutrophil activator as well as a superoxide primer. Therefore, ET-1-treated monocytes probably upregulate neutrophil superoxide production via a mechanism which includes IL-8.

First Page

184

Last Page

7

DOI

10.1097/00024382-199403000-00005

Publication Date

3-1-1994

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