Chapter 3 - Lung aging and senescence in health and disease

Abstract

Aging is a physiological process that affects most living organisms characterized by a time-dependent functional decline that leads to impaired function and increased vulnerability to death. As any other organ, the lungs age physiologically but they can also undergo abnormal aging. Cellular senescence is one of the “hallmarks of aging” albeit not the only one. This term refers to a functional state of the cell characterized by irreversible cell-cycle arrest combined with active secretion of many proinflammatory proteins, collectively known as the “Senescence-Associated Secretory Phenotype,” that recruit immune cells to promote tissue renewal and remodeling. However, cellular senescence can become deleterious when senescent cells abnormally accumulate in the tissue. Many of these hallmarks of aging are dysregulated in two prevalent and relevant respiratory diseases such as chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis. In this chapter, we discuss how some of these biological processes contribute to the pathogenesis of these diseases, with special attention to cellular senescence, and how a better understanding of these mechanisms can open new opportunities to improve their treatment.