The age-related loss of skeletal muscle mass and function is accompanied by a decline in regenerative capacity. The processes that facilitate healthy muscle repair are complex, involving several phases of degradation and rebuilding of muscle tissue and the surrounding microenvironment. Specifically, myogenic progenitor cells known as satellite cells are the most influential in repairing damaged muscle tissue. Following injury, satellite cells become activated and migrate, proliferate and fuse with mature skeletal muscle fibers to restore homeostasis to the tissue. However, satellite cells do not act in isolation, a robust inflammatory response is necessary to facilitate successful and rapid healing. Macrophages are one of the first and most abundant immune cells to infiltrate damaged skeletal muscle tissue. Primarily, macrophages adapt to a proinflammatory state to clear the area of cellular debris, promote degradation of the extracellular matrix and stimulate satellite cell activation and proliferation. Afterwards, a timely transition to an anti-inflammatory state directs rebuilding of the extracellular matrix and terminal differentiation of satellite cells. Indeed, the inhibition of macrophage activity leads to impaired healing and loss of skeletal muscle function. Little is known regarding the behavior of macrophages in aged skeletal muscle following injury in humans. Thus, the objective of this dissertation is to investigate the age-related response of macrophages in human skeletal muscle, and their role in muscle repair.
College and Department
Life Sciences; Exercise Sciences
BYU ScholarsArchive Citation
Sorensen, Jacob R., "Repair and Adaptation of Aged Skeletal Muscle to Nonpathological Muscle Damage: The Influence of Macrophage Polarization" (2018). Theses and Dissertations. 7691.
satellite cells, macrophage, inflammation, exercise-induced muscle damage, extracellular matrix