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Intensive Care Med. 1998 Dec;24(12):1315-22.

Beta-adrenergic receptor-dependent and -independent stimulation of adenylate cyclase is impaired during severe sepsis in humans.

Author information

1
Service de Réanimation Médicale, Hôpital de l'Archet, Nice, France. gbernard@unice.fr

Abstract

OBJECTIVES:

a) To investigate the functional consequences of sepsis on the beta-adrenergic signal transduction in human circulating lymphocytes; b) to appreciate sepsis-associated catecholamine and cytokine release.

DESIGN:

Experimental, comparative study.

SETTING:

Research laboratory in a university hospital.

SUBJECTS:

Healthy controls (n = 10); critically ill patients who were not septic (n = 7); septic patients with severe sepsis or septic shock (n = 11).

MEASUREMENTS AND MAIN RESULTS:

Experiments were carried out using freshly isolated peripheral blood mononuclear cells (PBMC). We measured beta-adrenergic receptor (betaAR) number and affinity, and intracellular cAMP content at baseline and after the pharmacological stimulation of each component of the beta-adrenergic complex: betaAR with isoproterenol, Gs-protein with sodium fluoride (NaF), adenylate cyclase with forskolin. Catecholamine (adrenaline, noradrenaline) and cytokine (TNFalpha, IL-1alpha, IL-1beta, IL-6) serum levels were measured. In both septic and non-septic patients we observed a similar 40 % down-regulation of betaARs compared to controls, and a reduced basal and isoproterenol-stimulated cAMP accumulation (p < 0.05). The cAMP production elicited by NaF or forskolin was lower in septic patients than in the controls (p < 0.01). Forskolin-stimulated cAMP accumulation was significantly lower in septic patients than it was in non-septic ones (p < 0.001). Catecholamine serum concentrations were increased in the two patient groups without any significant difference. Elevated cytokine serum levels were detected in 45% of the septic patients (versus 14% of non-septic patients p < 0.05).

CONCLUSIONS:

Patients presenting with severe sepsis or septic shock have extended postreceptor defects of the beta-adrenergic signal transduction. This finding suggests a heterologous desensitization of adenylate cyclase stimulation.

PMID:
9885886
DOI:
10.1007/s001340050768
[Indexed for MEDLINE]

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