Targeting the NLRP3 inflammasome to reduce warm ischemic injury in donation after circulatory death heart

While the donation after circulatory death (DCD) heart transplantation is an emerging clinical practice, the primary source of donor hearts for transplantation remains donation after brain death (DBD) donors. DCD process induces formation of NOD-like receptor family pyrin domain containing-3 (NLRP3) inflammasome, a key mediator of inflammation-driven damage to heart. Inhibition of NLRP3 inflammasome formation could be protective to DCD hearts. Five groups (n = 8 each) of mice were studied-control beating heart donor (CBD) wild-type (WT), DCD WT, CBD NLRP3 knockout (KO), DCD NLRP3 KO, and DCD WT NLRP3 inhibitor group. Hearts were procured and reanimated on a Langendorff system to assess physiologic parameters and then for molecular assays. NLRP3 inhibitor (50 mu mol/L) was administered to the DCD-NLRP3 inhibitor group at reanimation. Tissue NLRP3 levels were 80% higher in the DCD WT group compared with the CBD-WT group. Caspase-1 activity was significantly elevated in DCD WT but not in KO or NLRP3 inhibitor groups. The developed pressures and +/- dP/dt were significantly impaired in the DCD WT group compared with the CBD-WT group,P < .05, but were well preserved in DCD-NLRP3 inhibitor group. The DCD process activates the NLRP3 inflammasome, contributing to myocardial damage and dysfunction. NLRP3 inflammasome inhibition limits myocardial injury and preserves DCD heart function.