These effects might be ascribed to IL-1α and osteopontin, because gene expression of Il1α and Spp1 is increased in M2 macrophages at 7 days after MI, and neutralization of IL-1α or osteopontin significantly reduces the fibroblast-myofibroblast transition when cocultured with M2 macrophages (86). Here, SPP1 is linked to myocardial infarction.