Liraglutide Protects Lungs from Sepsis Damage by Restoring Surfactant Production

Liraglutide, a GLP-1 receptor agonist, protected mice from sepsis-induced acute lung injury (ALI) by restoring pulmonary surfactant production and inhibiting excessive autophagy. Treated mice survived longer, had less lung inflammation, less pulmonary edema (lower wet/dry weight ratio), and less cell death compared to untreated ALI mice. In cell culture, liraglutide reversed the damage caused by bacterial toxins (LPS) and restored expression of surfactant proteins SP-A and SP-B. The protective effects were blocked by rapamycin (an autophagy activator), confirming that liraglutide works by inhibiting autophagy.

C57BL/6 mice were given an ALI model and then treated with subcutaneous liraglutide at different concentrations. Researchers measured survival rates, lung wet/dry weight ratios, inflammatory markers in bronchoalveolar lavage fluid, lung tissue damage, and cell death. In parallel, MLE-12 lung epithelial cells were stimulated with LPS and treated with liraglutide, measuring cell viability, proliferation, apoptosis, surfactant protein expression (SP-A, SP-B), and autophagy markers. Rapamycin was used to confirm the autophagy-dependent mechanism.

Sepsis-induced acute lung injury is a life-threatening condition with limited treatment options and high mortality. This study reveals an unexpected therapeutic role for liraglutide — a drug millions take for diabetes and obesity — in protecting lungs during sepsis. The mechanism through pulmonary surfactant regulation is particularly interesting because surfactant dysfunction is a hallmark of acute respiratory distress syndrome (ARDS).

This study adds to a growing body of research showing GLP-1 drugs have anti-inflammatory and organ-protective effects far beyond blood sugar and weight management. The lung protection findings are part of an emerging pattern: GLP-1 receptor agonists appear to reduce inflammation and tissue damage across multiple organ systems. If these effects translate to humans, existing GLP-1 drugs could be repurposed for critical care settings.

This is an animal study in mice with a chemically induced sepsis model, which may differ from the complexity of human sepsis. The cell line used (MLE-12) is a mouse lung epithelial cell line, not primary human cells. The study did not test different timing windows for liraglutide administration, and the optimal dose for lung protection in humans is unknown. The sepsis model may not capture all aspects of clinical ALI/ARDS.