Aerobic exercise + weight loss decreases skeletal muscle myostatin expression and improves insulin sensitivity in older adults

Authors

  • A.S. Ryan,

    Corresponding author
    1. Baltimore Geriatric Research, Education and Clinical Center (GRECC), VA Maryland Health Care System, Baltimore, MD, USA
    • Baltimore VAMC, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
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  • G. Li,

    1. Baltimore VAMC, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
    2. Baltimore Geriatric Research, Education and Clinical Center (GRECC), VA Maryland Health Care System, Baltimore, MD, USA
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  • J.B. Blumenthal,

    1. Baltimore VAMC, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
    2. Baltimore Geriatric Research, Education and Clinical Center (GRECC), VA Maryland Health Care System, Baltimore, MD, USA
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  • H.K. Ortmeyer

    1. Baltimore VAMC, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
    2. Baltimore Geriatric Research, Education and Clinical Center (GRECC), VA Maryland Health Care System, Baltimore, MD, USA
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  • Clinical Trials #: NCT00882141

  • Disclosure: The authors declared no conflict of interest.

  • Funding agencies: This research was supported by the grant (RO1-AG19310, K01 AG021457, P30 AG028747, P30 DK072488, P60 DK079637, and M01 RR016500) from NIH, Baltimore VA Medical Research Service, VA Research Career Scientist Award (ASR), VA Merit Award, VA Career Development Award (JB), Department of Veterans Affairs and Veterans Affairs Medical Center Baltimore Geriatric Research, Education and Clinical Center (GRECC).

Correspondence: A.S. Ryan (aryan@grecc.umaryland.edu)

Abstract

Objective

To determine whether aerobic exercise training + weight loss (AEX + WL) would affect the expression of myostatin and its relationship with insulin sensitivity in a longitudinal, clinical intervention study.

Design and Methods

Thirty-three obese sedentary postmenopausal women and men (n = 17 and 16, age: 61 ± 1 years, body mass index: 31 ± 1 kg/m2, VO2max: 21.9 ± 1.0 mL/kg/min, X ± Standard error of the mean (SEM)) completed 6 months of 3 days/week AEX + WL. During an 80 mU m−2 min−1 hyperinsulinemic-euglycemic clamp, we measured glucose utilization (M), myostatin, myogenin, and MyoD gene expression by real-time RT-PCR in vastus lateralis muscle at baseline and 2 h.

Results

Body weight (−8%) and fat mass (−17%) decreased after AEX + WL (P < 0.001). Fat-free mass (FFM) and mid-thigh muscle area by computed tomography did not change but muscle attenuation increased (P < 0.05). VO2max increased 14% (P < 0.001). AEX + WL increased M by 18% (P < 0.01). Myostatin gene expression decreased 19% after AEX + WL (P < 0.05). Basal mRNA myostatin levels were negatively associated with M before the intervention (r = −0.43, P < 0.05). Insulin infusion increased myoD and myogenin expression before and after AEX + WL (both P < 0.001) but basal levels did not change. The insulin effect on myostatin expression was associated with the change in M after AEX + WL (r = 0.56, P < 0.005).

Conclusions

Exercise and weight loss results in a downregulation of myostatin mRNA and an improvement in insulin sensitivity in obese older men and women.

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