Plasma concentrations and anti-L-cytokine effects of alpha-melanocyte stimulating hormone in septic patients

Abstract

Objectives: The aim of this research was to investigate endogenous concentrations and anti-cytokine effects of the antiinflammatory peptide alpha-melanocyte stimulating hormone (alpha-MSH) in patients with systemic inflammation. The objectives were to determine the following: changes over time of plasma alpha-MSH and relationship with patient outcome, correlation between plasma alpha-MSH and tumor necrosis factor (TNF)-alpha plasma concentration and production in whole blood samples, and influences of alpha-MSH on production of TNF-alpha and interleukin (IL)-1beta in whole blood samples stimulated with lipopolysaccharide (LPS).

Design: Prospective, nonrandomized, clinical study.

Setting: Intensive care unit of a university hospital.

Patients: A total of 21 patients with sepsis syndrome/septic shock and an equal number of healthy volunteers.

Interventions: Circulating alpha-MSH and TNF-alpha concentrations and TNF-alpha production in supernatants of LPS (1 ng/mL)-stimulated whole blood were measured repeatedly. To determine whether alpha-MSH can modulate production of TNF-alpha and IL-1 beta, these cytokines were measured in whole blood samples stimulated with LPS (1 ng/mL) in the presence or absence of concentrations of the peptide.

Measurements and main results: Plasma alpha-MSH was low in early samples and gradually increased in patients who recovered but not in those who died. There was a negative correlation between plasma concentrations of alpha-MSH and TNF-alpha. In blood samples taken at early phases of sepsis syndrome, production of TNF-alpha was reduced relative to control values; such production increased in patients who recovered but not in those who died. Addition of alpha-MSH to LPS-stimulated whole blood samples inhibited production of TNF-alpha and IL-1beta in a concentration-dependent manner.

Conclusions: In patients with systemic inflammation, there are substantial changes over time in plasma concentrations of alpha-MSH that are reduced in early phases of the disease. Reduction of this endogenous modulator of inflammation could be detrimental to the host. Addition of alpha-MSH to LPS-stimulated blood samples reduces production of cytokines involved in development of septic syndrome. This inhibition by alpha-MSH, a peptide that is beneficial in treatment of experimental models of sepsis, might therefore be useful to treat sepsis syndrome in humans.