Stem Cell Aging in Lifespan and Disease: A State-of-the-Art Review

Aging is considered as inevitable changes at different levels of genome, cell, and organism. From the accumulation of DNA damages to imperfect protein homeostasis, altered cellular communication and exhaustion of stem cells, aging is a major risk factor for many prevalent diseases, such as cancer, cardiovascular disease, pulmonary disease, diabetes, and neurological disorders. The cells are dynamic systems, which, through a cycle of processes such as replication, growth, and death, could replenish the bodies' organs and tissues, keeping an entire organism in optimal working order. In many different tissues, adult stem cells are behind these processes, replenishing dying cells to maintain normal tissue function and regenerating injured tissues. Therefore, adult stem cells play a vital role in preventing the aging of organs and tissues, and can delay aging. However, during aging, these cells also undergo some detrimental changes such as alterations in the microenvironment, a decline in the regenerative capacity, and loss of function. This review aimed to discuss age-related changes of stem cells in different tissues and cells, including skin, muscles, brain, heart, hair follicles, liver, and lung.