Conflict/competing interest: No stated conflict of interest.
Orbicularis oculi: morphological changes mimicking mitochondrial cytopathy in a series of control normal muscles
Article first published online: 23 DEC 2011
© 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists
Clinical & Experimental Ophthalmology
Volume 40, Issue 5, pages 497–502, July 2012
How to Cite
McKelvie, P., Satchi, K., McNab, A. A. and Kennedy, P. (2012), Orbicularis oculi: morphological changes mimicking mitochondrial cytopathy in a series of control normal muscles. Clinical & Experimental Ophthalmology, 40: 497–502. doi: 10.1111/j.1442-9071.2011.02727.x
Funding sources: This study has received Royal Victorian Eye and Ear Hospital research funding.
- Issue published online: 25 JUL 2012
- Article first published online: 23 DEC 2011
- Accepted manuscript online: 2 NOV 2011 03:32AM EST
- Received 19 July 2011; accepted 9 October 2011.
- cytochrome oxidase-negative fibres;
- fibre typing;
- myosin heavy chain immunohistochemistry;
- orbicularis oculi muscle;
- ‘ragged-red’ fibres
Introduction: Orbicularis oculi (OO) muscle has recently proposed as a suitable muscle for biopsy to diagnose mitochondrial cyopathy:
Methods: Enzyme histochemical and immunohistochemical studies were performed on OO muscle obtained from 18 patients aged 37–87 years (median 64 years), 6 males, 12 females, who were undergoing routine upper blepharoplasty surgery.
Results: We confirmed the marked type II fibre (fast myosin heavy chain) predominance (89%) but also noted a different proportion and distribution of mitochondria in these fibres with occasional pseudo-‘ragged-red’ fibres with prominent subsarcolemmal and cytoplasmic aggregation of mitochondria. Cytochrome oxidase-negative fibres and true ‘ragged-red’ fibres were found at all ages over 40 years at levels that approach those used for diagnosis of mitochondrial cytopathy in peripheral or limb skeletal muscles.
Conclusion: We would therefore urge caution in the use of OO as muscle biopsy for diagnosis of mitochondrial cytopathy and advise concomitant biopsy of limb skeletal muscle and/or supplementary genetic studies.