Capillary supply of the soft palate muscles is reduced in long-term habitual snorers.

BACKGROUND

Snoring and obstructive sleep apnea (OSA) cause vibration and stretch of the upper airway tissues that may result in neuromuscular damage and changes in the microcirculation.

OBJECTIVES

The aim of this investigation was to test whether long-term snoring affects capillary supply in soft palate muscles.

METHODS

Samples from the palatopharyngeus (PP) and uvula (UV) muscles were collected from 8 patients undergoing uvulo-palatopharyngoplasty because of habitual snoring and OSA. Control samples were obtained at autopsy. The muscles were analyzed using immunohistochemistry and morphometry.

RESULTS

The patients' palate muscles had a lower capillary density (PP 443 vs. 711 capillaries/mm(2), p < 0.001, and UV 452 vs. 624 capillaries/mm(2), p = 0.009), a lower number of capillaries related to an individual muscle fiber (PP 1.3 vs. 2.7, p = 0.003, and UV 1.0 vs. 1.9, p = 0.03) and a lower number of capillaries related to the fiber size (PP 0.9 vs. 2.1, p = 0.001, and UV 0.6 vs. 1.9, p = 0.002).

CONCLUSIONS

Our results indicate that reduced capillary supply of palate muscles plays a pathophysiological role in long-term snorers and OSA. The cause of the low capillary supply is unclear, but neuromuscular injury due to repeated vibratory and stretch trauma of the soft palate during snoring is a plausible mechanism.