Crocins Ameliorate Experimental Immune Checkpoint Inhibitor-Related Myocarditis by Targeting the Hpx/Nrf2/HO-1 Pathway.

Immune checkpoint inhibitors (ICIs) for cancer therapy may induce immune-related adverse events including myocarditis, which occurs infrequently but carries a high mortality rate. Crocins are the active constituents derived from Crocus sativus L. (saffron), and have demonstrated various bioactivities including anti-tumor, anti-inflammation, antioxidation, anti-ischemia, anti-aging, and neuroprotective effects. This study established a subcutaneous xenotransplanted tumor model of human liver cancer in nude mice to better mimic ICI-related myocarditis. Animal experimental results revealed that crocins improved cardiac function, relieved myocardial damage and autoimmune response, and suppressed oxidative stress and inflammatory reaction. Quantitative proteomics and Western blotting verification confirmed that crocins ameliorated experimental ICI-related myocarditis by targeting the Hpx/Nrf2/HO-1 pathway. Molecular docking revealed that the best docking activities were demonstrated by crocin I-HO-1, crocin II-Hpx, and crocin III-Nrf2. These findings shed new light on the development of therapeutic strategies for treating ICI-related myocarditis and provided the fundamental basis for expanding the clinical application of crocins.