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Lipopolysaccharide: neutralization by polymyxin B shuts down the signaling pathway of nuclear factor kappaB in

H Tsuzuki1, T Tani, H Ueyama

  • 1First Department of Surgery, Shiga University of Medical Science, Seta-tsukinowa-cho, Otsu-city, Shiga, 520-2192, Japan. tsuzukih@smile.ocn.ne.jp

The Journal of Surgical Research
|August 23, 2001
PubMed
Abstract

Insights

Polymyxin B (PMX) neutralizes lipopolysaccharide (LPS), rapidly reducing inflammatory cytokines like tumor necrosis factor alpha (TNF-alpha) by inhibiting nuclear factor kappaB (NF-kappaB) activation. This endotoxin neutralization offers therapeutic potential for sepsis and endotoxin shock.

Area of Science:

  • Biochemistry
  • Immunology
  • Pharmacology

Background:

  • Lipopolysaccharide (LPS) is a key endotoxin implicated in sepsis and endotoxin shock.
  • Polymyxin B (PMX) is an agent used to neutralize LPS, but its precise mechanisms for reducing clinical mediators remain unclear.
  • Previous studies highlight PMX's ability to reduce circulating endotoxin and cytokines, even in severe cases.

Purpose of the Study:

  • To investigate the mechanisms by which PMX treatment reduces plasma cytokines through endotoxin neutralization.
  • To examine the relationship between PMX, LPS, and the subsequent modulation of inflammatory mediators.

Main Methods:

  • Studied the interaction between nuclear factor kappaB (NF-kappaB) binding activity and tumor necrosis factor alpha (TNF-alpha) secretion in vitro.
  • Utilized LPS-stimulated human peripheral blood mononuclear cells (PBMCs) and assessed TNF-alpha secretion and NF-kappaB activation.
  • Administered polymyxin B simultaneously with LPS or at 30 and 120 minutes post-LPS stimulation.

Main Results:

  • Immediate inhibition of NF-kappaB binding activity was observed upon LPS neutralization with polymyxin B.
  • Suppression of TNF-alpha secretion was achieved regardless of the timing of polymyxin B administration relative to LPS stimulation.
  • These effects occurred even when PBMCs were already producing TNF-alpha.

Conclusions:

  • Polymyxin B's rapid inhibition of NF-kappaB activation and TNF-alpha secretion provides a key mechanism for its clinical efficacy.
  • Endotoxin neutralization by PMX is effective even in patients with high levels of pro-inflammatory cytokines.
  • These findings support the therapeutic value of PMX in managing sepsis and endotoxin shock.

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