Factors contributing to neuromuscular impairment and sarcopenia during aging.
Motor disturbances and wasting of skeletal muscles (sarcopenia) causes significant impairment of daily life activities and is a major underlying cause for hospitalization in senescence. Herein we review data and present new findings on aging-specific changes in motoneurons, skeletal muscle and the interplay between motoneurons and target muscle fibers. Although many of the changes occurring during aging may be specific to motoneurons and myofibers, respectively, evidence indicates that myofiber regeneration in sarcopenic muscle is halted at the point where reinnervation is critical for the final differentiation into mature myofibers. Combined, evidence suggests that sarcopenia to a significant extent depend on a decreased capacity among motoneurons to innervate regenerating fibers. There are also conspicuous changes in the expression of several cytokines known to play important roles in establishing and maintaining neuromuscular connectivity during development and adulthood. We also present data showing the usefulness of rodent models in studies of successful and unsuccessful patterns of aging. Finally, we show that not only dietary restriction (DR) but also activity and social environment may modulate the pattern of aging.
Edström
Erik
E
Karolinska Institutet, Department of Neuroscience, Retzius Laboratory, S-171 77 Stockholm, Sweden.
Altun
Mikael
M
Bergman
Esbjörn
E
Johnson
Hans
H
Kullberg
Susanna
S
Ramírez-León
Vania
V
Ulfhake
Brun
B
D000375:Aging / Q000473:pathology / Q000502:physiology*; D000818:Animals; D016207:Cytokines / Q000378:metabolism; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000502:physiology; D009046:Motor Neurons / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000473:pathology / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation / Q000473:pathology*; D009133:Muscular Atrophy / Q000473:pathology / Q000503:physiopathology*
D016207:Cytokines; D036341:Intercellular Signaling Peptides and Proteins