C1-esterase inhibitor attenuates the inflammatory response during human endotoxemia

Area of Science:

• Immunology
• Inflammation research
• Complement system

Background:

• C1-esterase inhibitor (C1-INH) regulates complement and contact systems.
• C1-INH possesses immunomodulating properties relevant to acute inflammation (e.g., sepsis, trauma).
• Investigated C1-INH's effects in experimental human endotoxemia, bypassing classical complement activation.

Purpose of the Study:

• To examine the immunomodulating properties of C1-esterase inhibitor.
• To assess C1-INH's anti-inflammatory effects during human experimental endotoxemia.
• To determine if C1-INH impacts innate immune activation without classical complement pathway involvement.

Main Methods:

• Double-blind, placebo-controlled study with 20 healthy volunteers.
• Administered intravenous Escherichia coli lipopolysaccharide to induce endotoxemia.
• Infused C1-esterase inhibitor concentrate (100 U/kg) or placebo 30 minutes post-lipopolysaccharide.

Main Results:

• C1-esterase inhibitor significantly reduced pro-inflammatory cytokines (IL-6, MCP-1, IL-1β) and C-reactive protein.
• C1-INH increased anti-inflammatory cytokine interleukin-10 release.
• No significant differences observed in endothelial activation markers, hemodynamics, or symptoms between groups.

Conclusions:

• C1-esterase inhibitor exhibits significant anti-inflammatory effects in humans.
• These effects occur independently of classical complement pathway activation.
• C1-INH represents a potential therapeutic agent for acute inflammatory conditions.