AGE

, Volume 27, Issue 2, pp 117–125

Exercise training effects on skeletal muscle plasticity and IGF-1 receptors in frail elders

  • Maria L. Urso
  • Maria A. Fiatarone Singh
  • Wenjing Ding
  • William J. Evans
  • Arthur C. Cosmas
  • Thomas G. Manfredi
Research article

DOI: 10.1007/s11357-005-1629-7

Cite this article as:
Urso, M.L., Fiatarone Singh, M.A., Ding, W. et al. AGE (2005) 27: 117. doi:10.1007/s11357-005-1629-7

Abstract

Age-related sarcopenia inhibits mobility, increasing the risk for developing many diseases, including diabetes, arthritis, osteoporosis, and heart disease. Tissue plasticity, or the ability to regenerate following stress, has been a subject of question in aging humans. We assessed the impact of 10-weeks of resistance training on markers of skeletal muscle plasticity and insulin growth factor-1 (IGF-1) receptor density in a sub sample of subjects who, in an earlier study, demonstrated enhanced immunohistochemical labeling of IGF following resistance training. Muscle biopsies from the vastus lateralis of five elderly men and women were taken prior to and following 10 weeks of resistance training (N = 3) or a control period (N = 2). Immunogold labeling and quantitative electron microscopy techniques were used to analyze markers of IGF-1 receptor density and tissue plasticity. The experimental subjects showed a 161 ± 93.7% increase in Z band damage following resistance training. Myofibrillar central nuclei increased 296 ± 120% (P = 0. 029) in the experimental subjects. Changes in the percent of damaged Z bands were associated with alterations in the presence of central nuclei (r = 0.668; P = 0.0347). Post hoc analysis revealed that the relative pre/post percent changes in myofibrillar Z band damage and central nuclei were not statistically different between the control and exercise groups. Exercise training increased myofibrillar IGF-1 receptor densities in the exercise subjects (P = 0.008), with a non-significant increase in the control group. Labeling patterns suggested enhanced receptor density around the Z bands, sarcolemma, and mitochondrial and nuclear membranes. Findings from this study suggest that the age-related downregulation of the skeletal muscle IGF-1 system may be reversed to some extent with progressive resistance training. Furthermore, skeletal muscle tissue plasticity in the frail elderly is maintained at least to some extent as exemplified by the enhancement of IGF-1 receptor density and markers of tissue regeneration

Key words

agingexerciseIGF-1 receptorsskeletal muscle

Copyright information

© Springer 2005

Authors and Affiliations

  • Maria L. Urso
    • 1
    • 2
  • Maria A. Fiatarone Singh
    • 3
    • 4
  • Wenjing Ding
    • 3
  • William J. Evans
    • 5
  • Arthur C. Cosmas
    • 6
  • Thomas G. Manfredi
    • 1
    • 7
  1. 1.Energy Metabolism LaboratoryUniversity of Rhode IslandKingstonUSA
  2. 2.Department of Exercise ScienceUniversity of MassachusettsAmherstUSA
  3. 3.Nutrition, Exercise Physiology, and Sarcopenia Laboratory, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on AgingTufts UniversityBostonUSA
  4. 4.School of Exercise and Sport ScienceUniversity of SydneyLidcombeAustralia
  5. 5.Donald W. Reynolds Department of Geriatrics and Geriatric Research, Education, and Clinical CenterUniversity of Arkansas for Medical Sciences, Veterans Affairs Medical CenterLittle RockUSA
  6. 6.Allied Health ProfessionsUniversity of ConnecticutStorrsUSA
  7. 7.Exercise ScienceUniversity of Rhode IslandKingstonUSA