It is possible that degenerating neurons can release macrophage colony-stimulating factor 1 (CSF1 or M-CSF) and IL-34, which can accelerate the microglial proliferation capacity to recruit newly formed microglia to the plaques and eventually reach the Hayflick limit, causing replicative microglial senescence in AD [145,146,147,148]. Here, CSF1 is linked to Alzheimer disease.