Satellite cells in human skeletal muscle; from birth to old age

Abstract

Changes in satellite cell content play a key role in regulating skeletal muscle growth and atrophy. Yet, there is little information on changes in satellite cell content from birth to old age in humans. The present study defines muscle fiber type-specific satellite cell content in human skeletal muscle tissue over the entire lifespan. Muscle biopsies were collected in 165 subjects, from different muscles of children undergoing surgery (<18 years; n = 13) and from the vastus lateralis muscle of young adult (18–49 years; n = 50), older (50–69 years; n = 53), and senescent subjects (70–86 years; n = 49). In a subgroup of 51 aged subjects (71 ± 6 years), additional biopsies were collected after 12 weeks of supervised resistance-type exercise training. Immunohistochemistry was applied to assess skeletal muscle fiber type-specific composition, size, and satellite cell content. From birth to adulthood, muscle fiber size increased tremendously with no major changes in muscle fiber satellite cell content, and no differences between type I and II muscle fibers. In contrast to type I muscle fibers, type II muscle fiber size was substantially smaller with increasing age in adults (r = −0.56; P < 0.001). This was accompanied by an age-related reduction in type II muscle fiber satellite cell content (r = −0.57; P < 0.001). Twelve weeks of resistance-type exercise training significantly increased type II muscle fiber size and satellite cell content. We conclude that type II muscle fiber atrophy with aging is accompanied by a specific decline in type II muscle fiber satellite cell content. Resistance-type exercise training represents an effective strategy to increase satellite cell content and reverse type II muscle fiber atrophy.

Muscle satellite cells are functionally impaired in myasthenia gravis: consequences on muscle regeneration

“…On the other hand, as observed in our study, an increase in the SC pool was described in several cases such as degenerative muscle disease [34], neuromuscular disease as "arrested development of right response" (ADR) myotonia [63], drug treatment [56], or mechanical stress [11,76]. Moreover, it is known that both number and functionality of SCs are age-dependent with a significant decline during life span until senescence [7,74]. However, our results were carried out without any specific treatment or stress, and cells were removed from their in vivo muscle environment and from the serum pathogenic factors.…”

Premature aging in chronic kidney disease and chronic obstructive pulmonary disease

“…A loss of stem cell capacity may induce a reduced regenerative capacity in both the vascular system and muscle. Moreover, satellite cells, precursors of myocytes derived from mesenchymal stem cells, become depleted during the course of aging [22]. Although no reduction in the absolute number of satellite cells was observed in quadriceps muscle from patients with COPD, increased senescence, atrophic signaling and reduced differentiation potential were noted in this cell population [23].…”

Exercise and Stem Cells

“…[112][113][114][115] Resistance exercise training can also increase satellite cell content in young and aged men and women, 113,[116][117][118][119] and the increase has been demonstrated to be specific to type II fibers in elderly men and correlated with fiber size or muscle volume in young and aged men. 120,121 The strong relationship between satellite cell content and muscle fiber size postexercise would suggest a role for the satellite cell in growth, yet myonuclear accretion and/or new fiber synthesis are not consistently observed posttraining. 117,118,120,122,123 Conditional ablation of the Pax7 + cell using genetically altered mice (Pax7 iCE/+ : R26R DTA/+ ) also does not compromise growth in response to chronic loading in mice, 110 suggesting that the satellite cell may fulfill an alternative or additional role in muscle postexercise.…”