Article of Significant Interest Selected from This Issue by the Editors

Loss of Skeletal Muscle in Old Age Associated with Cellular Engine Trouble

Sarcopenia is the age-associated loss of skeletal muscle. In this issue, Ibebunjo et al. (p. 194–212) monitored cohorts of rats aged 6 to 27 months (old age) and demonstrated a reproducible loss in skeletal mass and strength starting at 21 months and proceeding in a linear decline, reminiscent of human sarcopenia. Changes in gene expression during sarcopenia were correlated with proteomics, providing an unbiased systems analysis indicating that sarcopenia is presaged by a decline in mitochondrial function. Therefore, failure of the “cellular engine,” the mitochondrion, might provide the initial mechanism for sarcopenia, suggesting an area of study for potential treatment.