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Muscle fibre type and obstructive sleep apnea
L J Ferini-Strambi1, S Smirne, U Moz
1State University of Milano and IRCSS H S. Raffaele, Sleep Disorders Center, Milan 20127, Italy.
Sleep Research Online : SRO
|May 31, 2001
Summary
Obstructive Sleep Apnea (OSA) causes specific muscle changes in the pharynx, not other muscles. These pharyngeal muscular abnormalities in OSA patients suggest an adaptive response to airway resistance.
Area of Science:
- Physiology
- Neurology
- Sleep Medicine
Background:
- Muscular pharyngeal structural changes, like fiber type disproportion, are observed in Obstructive Sleep Apnea (OSA).
- The cause of these abnormalities—whether secondary to increased activity or constitutional—remains unclear.
Purpose of the Study:
- To morphologically evaluate the Medium Pharyngeal Constrictor Muscles (MPCM) in OSA patients versus non-OSA controls.
- To investigate potential differences in skeletal muscle characteristics between the groups.
Main Methods:
- Morphological evaluation of MPCM from 13 OSA and 9 non-OSA patients.
- Needle biopsy of Vastus Lateralis Muscle (VLM) from 5 patients in each group.
Main Results:
- OSA patients showed specific fiber type disproportion in MPCM, with a Type II predominance.
- Myopathic changes like fibrosis and central nuclei were noted in OSA MPCM.
- No significant differences were found in the VLM between OSA and non-OSA groups.
Conclusions:
- Pharyngeal muscle changes in OSA are likely adaptive transformations due to nocturnal upper airway resistance.
- These findings differentiate pharyngeal muscle responses from other skeletal muscles in OSA.