In addition to metabolic mediators,17,18 recent work has implicated the inflammatory cytokine IL-1β in the development of trained immunity.42 This is particularly relevant because IL-1β has been identified in diabetes43 as an important driver of atherosclerosis and in obesity in which adipose tissue macrophage-produced IL-1β induces proliferation of BM progenitors.44,45 Therefore, we hypothesized that IL-1β and hyperglycemia may work synergistically to induce atherosclerosis-relevant epigenetic changes that alter chromatin structure. Here, IL1B is linked to obesity due to melanocortin 4 receptor deficiency.