Effects of Vasopressors on Immune Response

Endotoxemia

noradrenaline, vasopressin, phenylephrine, endotoxemia, Lipopolysaccharide, vasopressor

Noradrenaline is a catecholamine and the cornerstone treatment for the improvement of hemodynamic parameters in septic shock. Catecholamines exert profound immunomodulatory effects. Noradrenaline in vitro inhibits LPS-induced pro-inflammatory cytokine production, however, the actions on immune function in vivo have not been assessed. Furthermore, effects on the immune system of viable vasopressor alternatives for the treatment of septic patients, namely phenylephrine and vasopressin, need to be established in humans in vivo.

Rationale: Septic shock is a major medical challenge associated with a high mortality rate and increasing incidence. It has become clear that the majority of septic patients do not succumb to an initial pro-inflammatory hit, but at a later time-point in a pronounced immunosuppressive state, so called 'immunoparalysis'. Noradrenaline is a catecholamine and the cornerstone treatment for the improvement of hemodynamic parameters in septic shock. However, catecholamines exert profound immunomodulatory effects which have mainly been studied for adrenaline. It profoundly inhibits LPS-induced production of TNF-α, and enhances production of anti-inflammatory IL-10 in vitro, as well as in animal and human models of inflammation. Although in vitro studies have shown that noradrenaline inhibits LPS-induced pro-inflammatory cytokine production as potently as adrenaline, the effects of noradrenaline on the immune system in vivo have not yet been studied. Furthermore, effects on the immune system of viable vasopressor alternatives for the treatment of septic patients, namely phenylephrine and vasopressin, need to be established in humans in vivo. Objective: To investigate whether noradrenaline exerts immunomodulatory effects in humans in vivo and to compare noradrenaline to other vasopressors (phenylephrine and vasopressin). Study design: A randomized double-blind placebo-controlled study in healthy human volunteers during experimental endotoxemia. Study population: 40 healthy male volunteers, aged 18-35 yrs. Intervention: 1. The noradrenaline group (n= 10): subjects that will receive intravenous infusion of noradrenaline 0.05 μg/kg/min for 5 hours, starting 60 minutes before intravenous administration of 2 ng/kg LPS. 2. The phenylephrine group (n=10): subjects that will receive intravenous infusion of phenylephrine 0.5 μg/kg/min for 5 hours, starting 60 minutes before intravenous administration of 2 ng/kg LPS. . 3. The vasopressin group (n = 10): subjects that will receive intravenous infusion of vasopressin 0.04 IU/min for 5 hours, starting 60 minutes before intravenous administration of 2 ng/kg LPS. 4. The placebo group (n = 10): subjects that will receive intravenous infusion of NaCl 0.9% for 5 hours, starting 60 minutes before intravenous administration of 2 ng/kg LPS. Main parameters/endpoints: The difference of LPS-induced TNF-α plasma concentrations following endotoxemia between the noradrenaline and the placebo groups

Netherlands