ABSTRACT
Satellite cells, the resident skeletal muscle stem cells, are key effectors in the complex multicellular and multistep processes of adult muscle homeostasis and response to injury. Their “satellite stem cell niche,” surrounded by the basal membrane and attached to the muscle fibers, is tightly regulated by a number of cell–cell and cell–extracellular matrix (ECM) interactions that, along with the activation of intra- and extracellular signaling pathways, may provoke structural and chemical changes that concur with the age-associated functional impairment of skeletal muscle. The impact of sarcopenia on elderly people’s health and quality of life (QoL) is severe. This chapter will summarize the complex interactions that are established between the muscle stem cells and their milieu, describing cellular, chemical, and physical aspects of their niche, as well as the niche-associated changes that concur in muscle aging. With the increase in the aging population, understanding these degenerative mechanisms has become a priority for health services worldwide, since relatively small gains in the modulation of regenerative pathways might already represent an enormous advantage and seriously impact the QoL of frail individuals.
