Parkinson disease affects peripheral sensory nerves in the pharynx

Liancai Mu, Stanislaw Sobotka, Jingming Chen, Hungxi Su, Ira Sanders, Themba Nyirenda, Charles Howard Adler, Holly A. Shill, John Nathaniel Caviness, Johan E. Samanta, Lucia I. Sue, Thomas G. Beach

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55 Scopus citations

Abstract

Dysphagia is very common in patients with Parkinson disease (PD) and often leads to aspiration pneumonia, the most common cause of death in PD. Current therapies are largely ineffective for dysphagia. Because pharyngeal sensation normally triggers the swallowing reflex, we examined pharyngeal sensory nerves in PD patients for Lewy pathology.Sensory nerves supplying the pharynx were excised from autopsied pharynges obtained from patients with clinically diagnosed and neuropathologically confirmed PD (n = 10) and healthy age-matched controls (n = 4). We examined the glossopharyngeal nerve (cranial nerve IX), the pharyngeal sensory branch of the vagus nerve (PSB-X), and the internal superior laryngeal nerve (ISLN) innervating the laryngopharynx. Immunohistochemistry for phosphorylated α-synuclein was used to detect Lewy pathology. Axonal α-synuclein aggregates in the pharyngeal sensory nerves were identified in all of the PD subjects but not in the controls. The density of α-synuclein-positive lesions was greater in PD patients with dysphagia versus those without dysphagia. In addition, α-synuclein-immunoreactive nerve fibers in the ISLN were much more abundant than those in cranial nerve IX and PSB-X. These findings suggest that pharyngeal sensory nerves are directly affected by pathologic processes in PD. These abnormalities may decrease pharyngeal sensation, thereby impairing swallowing and airway protective reflexes and contributing to dysphagia and aspiration.

Original languageEnglish (US)
Pages (from-to)614-623
Number of pages10
JournalJournal of Neuropathology and Experimental Neurology
Volume72
Issue number7
DOIs
StatePublished - Jul 2013

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Keywords

  • Alpha-synuclein aggregates
  • Dysphagia
  • Glossopharyngeal nerve
  • Immunohistochemistry
  • Internal superior laryngeal nerve
  • Lewy neurites
  • Nerve degeneration
  • Parkinson disease
  • Peripheral nervous system
  • Pharyngeal sensory nerves
  • Pharynx
  • Swallowing
  • Vagus nerve

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Clinical Neurology
  • Neurology
  • Cellular and Molecular Neuroscience

Cite this

Mu, L., Sobotka, S., Chen, J., Su, H., Sanders, I., Nyirenda, T., Adler, C. H., Shill, H. A., Caviness, J. N., Samanta, J. E., Sue, L. I., & Beach, T. G. (2013). Parkinson disease affects peripheral sensory nerves in the pharynx. Journal of Neuropathology and Experimental Neurology, 72(7), 614-623. https://doi.org/10.1097/NEN.0b013e3182965886