Aging of human muscle: understanding sarcopenia at the single muscle cell level

Abstract

The loss of muscle mass with age, also known as sarcopenia, is a major scientific and public health problem. Muscle atrophy is associated with the loss of functional capacity and poor health outcomes in elderly men and women. A detailed understanding of this problem in humans can be enhanced by the use of experiments with single muscle fibers. It is likely that both muscle atrophy and a decrease in muscle-fiber quality contribute to muscle dysfunction among the elderly. A better understanding of sarcopenia at the single-fiber level may lead to the design of more effective rehabilitative interventions.

Figure 1

Images of dissected single human muscle fiber (a), attached to force transducer and servomotor (b), and preserved sarcomere pattern at higher magnification (c).

Figure 2

Force-velocity and power-velocity curves from human single muscle fiber segments.

Figure 3

Scatter plot of fiber CSA and maximal force (P₀) for single muscle fibers from young (□, type I; △, type IIa) and older men (■, type I; ▲, type IIa).

Figure 4

Mean specific force (SF) of type IIA fibers (n=465) from m. vastus lateralis in young and older men (N=34) and women (N=47). Values are expressed as mean ± SD. N=number of subjects and n=number of fibers.