Heme-Inducing Endothelial Pyroptosis Plays a Key Role in Radiofrequency Ablation of Hepatic Hemangioma Leading to Systemic Inflammatory Response Syndrome.

Purpose: Systemic inflammatory response syndrome (SIRS) is a common complication of radiofrequency ablation (RFA) for hepatic hemangiomas. RFA can cause hemolytic reactions during hepatic hemangioma ablation. However, the mechanisms underlying RFA-induced SIRS remain unclear.

Methods: We established an orthotopic liver hemangioma model and performed radiofrequency ablation. The levels of interleukin (IL)-1β and IL-18 and the production of ROS were measured. The wet-to-dry lung ratio, inflammation score, and in vivo endothelial cell permeability were examined. GSDMD mice were used to investigate the effect of heme-inducing SIRS. RNA sequencing (RNA-seq) was performed to identify the main pathways underlying heme-induced SIRS. Western blotting and immunoprecipitation were used to determine the changes and interactions of associated proteins.

Results: The levels of heme, IL-1β, and IL-18 were significantly increased after RFA. The wet-to-dry lung ratio increased in hepatic hemangiomas after RFA, indicating that SIRS occurred. Heme induced increased levels of IL-1β and IL-18, cell death, wet-to-dry lung radio, and inflammation score in vitro and in vivo, indicating that heme induced SIRS and pyroptosis. Furthermore, GSDMD participates in heme-induced SIRS in mice, and GSDMD deletion in mice reverses the effect of heme. Heme regulates NLRP3 activation through the NOX4/ROS/TXNIP-TRX pathway, and an N-acetyl-L-cysteine (NAC) or NOX4 inhibitor (GLX351322) reverses heme-induced SIRS.

Conclusion: Our findings suggest that heme induces endothelial cell pyroptosis and SIRS in mice and decreasing heme levels and ROS scavengers may prevent SIRS in hepatic hemangioma after RFA.