Influence of weight and sleep apnea status on immunologic and structural features of the uvula.

We investigated the influence of weight and obstructive sleep apnea status on inflammatory and histologic features of the uvula. Tissue samples resected during uvulopalatopharyngoplasty in 11 snorers without obstructive sleep apnea, 11 subjects with obstructive sleep apnea and of similar body mass index and age, and 8 additional obese subjects with obstructive sleep apnea were examined by immunohistochemistry and histologic staining techniques. The frequency and distribution of immune cells, the amount of collagen, and the integrity of the elastin fiber network were evaluated in proximal and distal uvular sections. T cell (CD4+, CD8+) and macrophage counts were higher in the more obese apneic subjects than in the other two groups. In all patients, T cell counts correlated with body mass index, but there was no relationship with the apnea-hypopnea index. A positive correlation was found between elastin fiber network disorganization score and apnea-hypopnea index. We conclude that (1) the amount of inflammatory markers is linked to obesity rather than to sleep-related breathing disorders, and (2) obstructive sleep apnea is associated with a structural alteration of the extracellular matrix of upper airway tissue.