However, a previous study found that intratracheal LPS increased lung edema, MPO activity, and the levels of pro-inflammatory cytokines, such as MIP-2, KC, MCP-1, MCP-3, to a similar extent in the BALF of wild-type and eNOS-/- mice, suggesting eNOS does not play a role in the pathogenesis of ALI [32]. Here, MPO is linked to acute respiratory distress syndrome.