Chronological and photoaging are responsible for skin aging. Photoaging produces typical signs of aging skin pigmentations like mottled pigmentation (senile lentigo) and melasma. Skin experiences cellular senescence which increases with age, similar to any other body organ. The crosstalk between melanocytes as pigmentary cells and other adjacent types of aged skin cells, such as senescent fibroblasts, triggers skin-aging pigmentation. 

The role of cellular senescence in skin pigmentation during the aging process is not a single process or pathway excepting some congenital and acquired disorders. Rather, complicated intercellular interactions may play a role in skin-aging pigmentation. Senescent cells alone or their effects on melanocytes as pigmentary cells can induce skin pigmentation with aging. 

A recent review suggested that the most important senescent cells in skin-aging pigmentation are fibroblasts and melanocytes. Furthermore, it adds that each cell type of these cells is mainly engaged in hyperpigmentation and hypopigmentation, respectively, in aged skin. Additionally, senescent melanocytes may further involve the neighboring skin cells. 

Thus, exploring possible therapeutic targets for senescence-related materials is crucial to treat and preventing skin aging and skin-aging pigmentation.

Source: Kim JC, Park TJ, Kang HY. Skin-aging pigmentation: who is the real enemy? Cells. 2022;11(16):2541.