Opsonic fibronectin deficiency and sepsis. Cause or effect?

Area of Science:

• Immunology
• Sepsis Pathophysiology
• Wound Healing & Trauma Response

Background:

• Opsonic fibronectin modulates macrophage and neutrophil phagocytic function.
• Fibronectin depletion occurs after trauma, burns, and surgery, usually with rapid recovery unless sepsis intervenes.
• A secondary phase of fibronectin deficiency precedes clinical sepsis in burn patients.

Purpose of the Study:

• To investigate if opsonic fibronectin deficiency increases susceptibility to sepsis.
• To determine the role of fibronectin depletion in host defense against bacterial infection.

Main Methods:

• Partial depletion (35%) of opsonic fibronectin in Sprague-Dawley rats.
• Intraperitoneal inoculation with Staphylococcus aureus to induce peritonitis.
• Monitoring mortality rates and fibronectin levels in depleted and control groups.

Main Results:

• Fibronectin-depleted rats showed significantly increased mortality from S. aureus peritonitis (p < 0.05).
• Non-surviving control animals had significantly lower initial fibronectin levels than survivors (p < 0.05).
• Peritonitis induced early fibronectin depletion followed by hyperopsonemia within 12 hours in all rats.

Conclusions:

• Opsonic fibronectin depletion decreases host resistance to sepsis.
• Sepsis development triggers opsonic fibronectin deficiency.
• Early restoration and maintenance of fibronectin levels are crucial for host defense post-trauma and infection.