Ulinastatin

Systemic inflammation is involved in developing acute kidney injury (AKI) after cardiac surgery with cardiopulmonary bypass (CPB). Ulinastatin, a urinary trypsin inhibitor (UTI), has various anti-inflammatory effects. Our previous data displayed that UTI administration during CPB played a protective role in reducing the risk of AKI after cardiac surgery; however, its role in AKI pathogenesis remains unknown. In this study, UTI effectively decreased the expression levels of inflammatory factors, including tumor necrosis factor (TNF)-α, interleukin (IL)-6, and interleukin (IL)-18, in patients with CPB. Moreover, the proportion of patients with postoperative AKI decreased significantly. Experimental AKI was induced by 35 min of ischemia, followed by 48 h of reperfusion.The results showed that the preoperative administration of UTI reduced inflammatory cell infiltration and decreased the levels of pro-inflammatory cytokines, including IL-6, IL-18, and TNFα. Meanwhile, UTI inhibited apoptosis, reduced mitochondrial reactive oxygen species production. We further revealed that UTI could inhibit NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome activation by increasing the expression of nuclear factor-κB (IκB) kinase-alpha (IKKα) interacting with apoptosis-associated speck-like protein containing CARD (ASC) to alleviate kidney damage. These findings provide evidence of the renoprotective role of UTI in cardiac surgery-associated (CSA)-AKI, which is associated with the inhibition of NLRP3 inflammasome activation by upregulating IKKα.