This activation, in turn, induces macrophage infiltration into the heart and promotes M1 macrophage polarization.237 Meanwhile, abnormal glycemic variability (changes in blood glucose over time) in diabetics promotes M1 macrophage polarization through sodium-glucose cotransporter 1 (SGLT1).238 These inflammatory macrophages secrete inflammatory cytokines, including TNF-α, IL-1β, IL-6, etc., which act on CFs and promote the occurrence of myocardial fibrosis. Here, SLC5A1 is linked to diabetes mellitus.