Per S Stål1, Rolf Lindman, Bengt Johansson. 1. Section of Anatomy, Department of Integrative Medical Biology, Umeå University, Umeå, Sweden. per.stal@anatomy.umu.se
Abstract
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. Copyright 2009 S. Karger AG, Basel.
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. Copyright 2009 S. Karger AG, Basel.