title: Altered pharyngeal muscles in Parkinson disease.
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.
authors.affiliation: Upper Airway Research Laboratory, Department of Research, Hackensack University Medical Center, Hackensack, New Jersey 07601, USA. lmu@humed.com
authors.forename: Liancai
authors.initials: L
authors.lastname: Mu
authors.forename: Stanislaw
authors.initials: S
authors.lastname: Sobotka
authors.forename: Jingming
authors.initials: J
authors.lastname: Chen
authors.forename: Hungxi
authors.initials: H
authors.lastname: Su
authors.forename: Ira
authors.initials: I
authors.lastname: Sanders
authors.forename: Charles H
authors.initials: CH
authors.lastname: Adler
authors.forename: Holly A
authors.initials: HA
authors.lastname: Shill
authors.forename: John N
authors.initials: JN
authors.lastname: Caviness
authors.forename: Johan E
authors.initials: JE
authors.lastname: Samanta
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Beach
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001284:Atrophy; D001344:Autopsy; D001921:Brain / Q000473:pathology; D003627:Data Interpretation, Statistical; D003679:Deglutition / Q000502:physiology; D003680:Deglutition Disorders / Q000209:etiology / Q000503:physiopathology; D003714:Denervation; D049631:Esophageal Sphincter, Upper / Q000294:innervation / Q000502:physiology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000473:pathology / Q000648:ultrastructure; D018995:Myosin Heavy Chains / Q000378:metabolism; D010300:Parkinson Disease / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D017933:Peripheral Nervous System / Q000473:pathology / Q000503:physiopathology; D010609:Pharyngeal Muscles / Q000294:innervation / Q000473:pathology* / Q000503:physiopathology; D010614:Pharynx / Q000294:innervation / Q000473:pathology; D012307:Risk Factors
chemical_list: D018995:Myosin Heavy Chains