Influence of catecholamines on cytokine production and expression of adhesion molecules of human neutrophils in vitro.

The impact of catecholamines on cytokine production and expression of adhesion molecules by human neutrophils was evaluated in vitro. Neutrophils were separated from venous blood of healthy subjects. The generation of intracellular cyclic adenosine monophosphate (cAMP) and Ca2+ was determined after incubation with catecholamines. Resting and lipopolysaccharide (LPS)-activated neutrophils were tested for synthesis of interleukins (IL-6, IL-8) and tumor necrosis factor alpha (TNF-alpha). In addition, the expression of the adhesion molecules CD15, CD44, and CD54 was evaluated in resting and activated neutrophils. Increasing concentrations (1 nM-1 mM) of epinephrine (EPI) were used to study the influence of activation of beta2-adrenergic receptors (beta2R) on cytokine production and adhesion molecule expression. Incubation with catecholamines induced an increase in cAMP but not Ca2+ in neutrophils. Only IL-8 was detected following stimulation with LPS and was unchanged upon co-incubation with EPI. The expression of CD15 and CD44 decreased spontaneously in vitro. The density of CD44 increased in the presence of very high doses of EPI (1 mM). Expression of CD54 on resting neutrophils increased upon activation. The density of CD54 on activated neutrophils was reduced upon co-incubation with 1 mM EPI for 6 h. However, 1 mM EPI for 12 and 18 h decreased the spontaneous loss of CD54 on resting neutrophils. Beta2R are functionally coupled to signalling cascades in human neutrophils. Nevertheless, the impact of catecholamines on IL-8 synthesis and expression of CD15, CD44, and CD54 is limited.