S100A9 and myocardial infarction: It has been discovered that S100A9 hi macrophages promote the acute inflammatory response and fibrotic process after MI by activation of Myd88/NFκB/NLRP3 and Tgf-β/p-smad3 signaling pathways (Marinković et al., 2020; Shen S. et al., 2024).