Norepinephrine Dysregulates the Immune Response and Compromises Host Defense during Sepsis.

Abstract

<b>Rationale:</b> Sepsis is characterized by a dysregulated immune response to infection. Norepinephrine, the cornerstone vasopressor used in septic shock, may contribute to immune dysregulation and impact host defense.<b>Objectives:</b> To investigate effects of norepinephrine and the alternative vasopressor vasopressin on the immune response and host defense.<b>Methods:</b> Leukocytes from six to nine donors were stimulated in the presence or absence of norepinephrine and vasopressin. A total of 190 C57BL/6J mice received a continuous infusion of norepinephrine or vasopressin via microosmotic pumps and were challenged with LPS or underwent cecal ligation and puncture. Thirty healthy volunteers were randomized to a 5-hour infusion of norepinephrine, vasopressin, or saline and intravenously challenged with LPS. The relationship between the norepinephrine infusion rate and the use of β-blockers and plasma cytokines was assessed in 195 patients with septic shock.<b>Measurements and Main Results:</b> Norepinephrine attenuated the production of proinflammatory mediators and reactive oxygen species and augmented antiinflammatory IL-10 production both <i>in vitro</i> and in LPS-challenged mice. Norepinephrine infusion during cecal ligation and puncture resulted in increased bacterial dissemination to the spleen, liver, and blood. In LPS-challenged volunteers, norepinephrine enhanced plasma IL-10 concentrations and attenuated the release of the proinflammatory cytokine IFN-γ-induced protein 10. Vasopressin exerted no immunomodulatory effects across these experimental setups. In patients, higher norepinephrine infusion rates were correlated with a more antiinflammatory cytokine balance, whereas β-blocker use was associated with a more proinflammatory cytokine balance.<b>Conclusions:</b> Norepinephrine dysregulates the immune response in mice and humans and compromises host defense. Therefore, it may significantly contribute to sepsis-induced immunoparalysis, whereas vasopressin does not have untoward immunologic effects.