Differential features of muscle fiber atrophy in osteoporosis and osteoarthritis

Osteoporosis International, 05/08/2012

Terracciano C et al. – This study shows that in osteoporosis (OP), there is a preferential and diffuse type II fiber atrophy, proportional to the degree of bone loss, whereas in Osteoarthritis (OA), muscle atrophy is connected to the functional impairment caused by the disease. A reduction of Akt seems to be one of the mechanisms involved in OP–related muscle atrophy.

Methods

  • The authors performed muscle biopsy in 15 women with OP and in 15 women with OA (age range, 60–85 years).
  • Muscle fibers were counted, measured, and classified by ATPase reaction.
  • By statistical analysis, fiber–type atrophy was correlated with bone mineral density (BMD) in the OP group and with Harris Hip Score (HHS) and disease duration in the OA group.
  • Akt protein levels were evaluated by Western blot analysis.

Results

  • The findings revealed in OP a preferential type II fiber atrophy that inversely correlated with patients’ BMD.
  • In OA, muscle atrophy was of lower extent, homogeneous among fiber types and related to disease duration and HHS.
  • Moreover, in OP muscle, the Akt level was significantly reduced as compared to OA muscles.

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