Reticuloendothelial function and plasma fibronectin in a murine model of intra-abdominal sepsis

Area of Science:

• Pathophysiology
• Immunology
• Critical Care Medicine

Background:

• The lung is a primary target organ in early multiple organ failure.
• Pulmonary microembolisation, reticuloendothelial system (RES) dysfunction, and fibronectin depletion are implicated in its pathogenesis.
• Understanding these mechanisms is crucial for treating severe sepsis.

Purpose of the Study:

• To investigate changes in plasma fibronectin, RES phagocytic function, particle localization, endotoxin, and fibrin degradation products in a murine model of severe intra-abdominal infection.
• To elucidate the role of RES function in pulmonary microembolisation during sepsis.

Main Methods:

• A clinically relevant murine model of severe intra-abdominal infection was utilized.
• Concurrent measurements of plasma fibronectin, RES phagocytic function, organ particle localization (bacterial and lipid emulsions), circulating endotoxin, and fibrin degradation products were performed.
• Septic and control groups were compared over 48 hours.

Main Results:

• Progressive sepsis led to a significant decline in RES phagocytic function (to 45% of control values within 48 hours).
• Hepatosplenic uptake of particles decreased, while pulmonary localization increased.
• Plasma fibronectin levels rose in septic animals, indicating increased production.

Conclusions:

• Altered RES function in sepsis impairs particle clearance, facilitating pulmonary microembolisation.
• These findings support the hypothesis that RES dysfunction is a key factor in the pathogenesis of septic multiple organ failure.
• Targeting RES function may offer therapeutic strategies for sepsis-induced organ damage.