Hallmarks of Aging in Macrophages: Consequences to Skin Inflammaging

The skin is our largest organ and the outermost protective barrier. Its aging reflects both intrinsic and extrinsic processes resulting from the constant insults it is exposed to. Aging in the skin is accompanied by specific epigenetic modifications, accumulation of senescent cells, reduced cellular proliferation/tissue renewal, altered extracellular matrix, and a proinflammatory environment favoring undesirable conditions, including disease onset. Macrophages (M phi) are the most abundant immune cell type in the skin and comprise a group of heterogeneous and plastic cells that are key for skin homeostasis and host defense. However, they have also been implicated in orchestrating chronic inflammation during aging. Since M phi are related to innate and adaptive immunity, it is possible that age-modified skin M phi promote adaptive immunity exacerbation and exhaustion, favoring the emergence of proinflammatory pathologies, such as skin cancer. In this review, we will highlight recent findings pertaining to the effects of aging hallmarks over M phi, supporting the recognition of such cell types as a driving force in skin inflammaging and age-related diseases. We will also present recent research targeting M phi as potential therapeutic interventions in inflammatory skin disorders and cancer.

Automated summary

Skin aging is a complex process influenced by various factors, leading to changes such as reduced cellular proliferation and alterations in the extracellular matrix. Macrophages (M phi) play a crucial role in skin homeostasis and host defense, but they have also been implicated in chronic inflammation during aging. Targeting M phi may offer potential therapeutic interventions for inflammatory skin disorders and cancer.