Abstract
Dysphagia (impaired swallowing) is common in patients with Parkinson disease (PD) and is related to aspiration pneumonia, the primary cause of death in PD. Therapies that ameliorate the limb motor symptoms of PD are ineffective for dysphagia. This suggests that the pathophysiology of PD dysphagia may differ from that affecting limb muscles, but little is known about potential neuromuscular abnormalities in the swallowing muscles in PD. This study examined the fiber histochemistry of pharyngeal constrictor and cricopharyngeal sphincter muscles in postmortem specimens from 8 subjects with PD and 4 age-matched control subjects. Pharyngeal muscles in subjects with PD exhibited many atrophic fibers, fiber type grouping, and fast-to-slow myosin heavy chain transformation. These alterations indicate that the pharyngeal muscles experienced neural degeneration and regeneration over the course of PD. Notably, subjects with PD with dysphagia had a higher percentage of atrophic myofibers versus with those without dysphagia and controls. The fast-to-slow fiber-type transition is consistent with abnormalities in swallowing, slow movement of food, and increased tone in the cricopharyngeal sphincter in subjects with PD. The alterations in the pharyngeal muscles may play a pathogenic role in the development of dysphagia in subjects with PD.
Original language | English (US) |
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Pages (from-to) | 520-530 |
Number of pages | 11 |
Journal | Journal of Neuropathology and Experimental Neurology |
Volume | 71 |
Issue number | 6 |
DOIs | |
State | Published - Jun 2012 |
Keywords
- Dysphagia
- Fiber types
- Immunohistochemistry
- Muscle fiber atrophy
- Myosin heavy chain isoforms
- Parkinson disease
- Pharyngeal constrictor muscles
- Swallowing
- Upper esophageal sphincter
ASJC Scopus subject areas
- Pathology and Forensic Medicine
- Neurology
- Clinical Neurology
- Cellular and Molecular Neuroscience