Pharyngeal Constrictor Muscle Fatty Change May Contribute To Obstructive Sleep Apnea-Hypopnea Syndrome: A Prospective Observational Study

Conclusions: Pharyngeal constrictor muscle injury and fatty changes may play important roles in the pathogenesis and progression of OSAHS.Objective: Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a respiratory disorder caused by upper airway obstruction during sleep. The primary objectives of this study were to determine the ultrastructural characteristics of the pharyngeal constrictor muscle in patients with OSAHS.Methods: A pharyngeal constrictor muscle specimen was collected from all subjects. The muscle cell ultrastructure was observed under electron microscopy.Results: Eighteen male patients with OSAHS (OSAHS group) and 10 male body mass index-matched patients with chronic tonsillitis (control group) were enrolled in this study. All patients were obese adults. The apnea-hypopnea index (41.22 +/- 17.29 vs 2.30 +/- 1.10 events/h) was significantly higher and the lowest arterial oxygen saturation (76.00 +/- 8.57% vs 97.00 +/- 2.00%) was significantly lower in the OSAHS group than in the control group (both p<0.001). Myofibril disorder, mitochondrial edema, and intramyocellular lipid droplets were observed in patients with OSAHS. There was a significant correlation between the number of lipid droplets and the apnea-hypopnea index.