Therapeutic effects of endothelial progenitor cells in LPS-induced ARDS

Background: Endotoxin-induced ARDS is characterized by diffuse dysfunction of the microvasculature including increased permeability with edema formation and apoptosis or necrosis of endothelial and epithelial cells. Concomitantly, an increased concentration of circulating endothelial progenitor cells (EPC) was found in septic patients, of which more than half have pulmonary involvement. The number of circulating EPC correlated inversely to disease severity and mortality. Since these EPC were found homing to damaged lung tissue, a reparative process seems to be initiated right after the initiation of vessel damage or degeneration. In the present study we investigated the potential of EPC as a treatment strategy in ARDS. Method: Bone marrow-derived EPC were administered systemically to rats suffering from LPS-induced isolated ARDS. LPS- or vehicle-treated rats served as controls. Results: Rats treated with EPC showed significantly improved pulmonary gas exchange, an inhibition of pro-inflammatory cytokine synthesis, an improved clinical course and a reduced mortality (p<0.024) compared to rats receiving LPS alone. Conclusion: These findings suggest that the application of exogenous EPC can reduce the severity of septic organ damage. EPC treatment might therefore become a novel therapeutic option in the management of sepsis.