Axon and Schwann Cell Degeneration in Nerves of Upper Airway Relates to Pharyngeal Dysfunction in Snorers and Patients With Sleep Apnea

Chest: The Journal of Circulation, Respiration and Related Systems

Thorbjörn Holmlund^2¹  Farhan Shah^1²  Eva Levring Jäghagen^3³  Diana Berggren^2⁴ 

[1] Department of Clinical Sciences, Otolaryngology, Umeå University, Umeå, Sweden^2;Department of Integrative Medical Biology, Laboratory of Muscle Biology, Umeå University, Umeå, Sweden^1;Department of Odontology, Oral and Maxillofacial Radiology, Umeå University, Umeå, Sweden^3;Department of Surgical and Perioperative Sciences, Surgery, Umeå University, Umeå, Sweden^4

关键词: muscle degeneration;    nerve injury;    OSA;    swallowing dysfunction;    upper airways;    AHI;    apnea-hypopnea index;    GAP-43;    growth associated protein 43;   

DOI  :  10.1016/j.chest.2018.06.017

学科分类：呼吸医学

来源: American College of Chest Physicians

【 摘 要 】

Background The pathophysiologic mechanism of nocturnal obstruction and swallowing dysfunction commonly occurring in patients with sleep apnea is unclear. The goal of this study was to investigate whether nerve injuries in the upper airways of snorers and patients with sleep apnea are associated with pharyngeal dysfunction and severity of sleep apnea. Methods Twenty-two patients undergoing palatal surgery due to snoring and sleep apnea were investigated for a swallowing dysfunction by using videoradiography. Twelve healthy nonsnoring subjects were included as control subjects. Tissue samples from the soft palate at the base of the uvula were obtained in all patients and control subjects. Nerves and muscle were analyzed with immunohistochemical and morphologic methods, and the findings were correlated with swallowing function and degree of sleep apnea. Results In the soft palate of patients, nerve fascicles exhibited a significantly lower density of axons (5.4 vs 17.9 × 10^–3 axons/μm²; P = .02), a smaller percentage area occupied by Schwann cells (17.5% vs 45.2%; P = .001) and a larger number of circular shaped Schwann cells lacking central axons (43.0% vs 12.7%; P r = 0.5; P = .03) and apnea-hypopnea index > 5 (P = .03). Regenerating axons were frequently observed in patients compared with control subjects (11.3 ± 4.2% vs 4.8 ± 2.4%; P = .02). Conclusions Axon degeneration in preterminal nerves of the soft palate is associated with pharyngeal dysfunction in snorers and patients with sleep apnea. The most likely cause for the nerve injuries is traumatic snoring vibrations and tissue stretch, leading to swallowing dysfunction and increased risk for upper airway obstruction during sleep.

【 授权许可】

CC BY