Metabolic fitness is decreased in monocytes of old individuals

defense, forming with macrophages and dendritic cells the first line of defense against invading pathogens [1]. With age, the host responses to infections and inflammatory stimuli decline, known as immunosenescence. This has been associated with the agerelated chronic inflammatory processes, inflamm-aging, in which monocytes and monocyte-derived macrophages have an important role, as they are actively involved in inflammatory processes. Furthermore, their function strongly influences age-related diseases including atherosclerosis, sepsis, Alzheimer's disease, and has been more recently associated with severe COVID-19 patients.