CASP1 and Sepsis: Disruption of the vascular barrier, along with the leakage of fluid and proteins into lungs, remain a predominant contributor to acute respiratory injury during sepsis.28,29 Therefore, we investigated whether inflammasome activation by flagellin induced an increase in vascular permeability by measuring the mouse lung capillary filtration coefficient (Kf,c).30,31 Following injection of LFn-flagellin/PA, the Kf,c was significantly elevated in WT mice, but not in the caspase-1-deficient mice (Figure 1C).