title: The extracellular matrix of the lateral pharyngeal wall in obstructive sleep apnea.
abstract: OBJECTIVE
  To compare the components of the extracellular matrix in the lateral pharyngeal muscular wall in patients with and without obstructive sleep apnea (OSA). This may help to explain the origin of the increased collapsibility of the pharynx in patients with OSA.
  
  
  METHODS
  Specimens from the superior pharyngeal constrictor muscle, obtained during pharyngeal surgeries, were evaluated using histochemical and immunohistochemical analyses to determine the fractional area of collagen types I and III, elastic fibers, versican, fibronectin, and matrix metalloproteinases 1 and 2 in the endomysium.
  
  
  METHODS
  Academic tertiary center. PATIENS: A total of 51 nonobese adult patients, divided into 38 patients with OSA and 13 nonsnoring control subjects without OSA.
  
  
  METHODS
  Postintervention study performed on tissues from patients after elective surgery.
  
  
  RESULTS
  Pharyngeal muscles of patients with OSA had significantly more collagen type I than pharyngeal muscles in control subjects. Collagen type I was correlated positively and independently with age. The other tested components of the extracellular matrix did not differ significantly between groups. In a logistic regression, an additive effect of both the increase of collagen type I and the increase in age with the presence of OSA was observed (odds ratio (OR), 2.06; 95% confidence interval (CI), 1.17-3.63), when compared with the effect of increased age alone (OR, 1.11; 95% CI, 1.03-1.20).
  
  
  CONCLUSIONS
  Collagen type I in the superior pharyngeal constrictor muscle was more prevalent in patients with OSA and also increased with age. It was hypothesized that this increase could delay contractile-relaxant responses in the superior pharyngeal constrictor muscle at the expiratory-inspiratory phase transition, thus increasing pharyngeal collapsibility.
authors.affiliation: Department of Otolaryngology, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil. andradeds@globo.com
authors.forename: Danielle Andrade da Silva
authors.initials: DA
authors.lastname: Dantas
authors.forename: Thais
authors.initials: T
authors.lastname: Mauad
authors.forename: Luiz F F
authors.initials: LF
authors.lastname: Silva
authors.forename: Geraldo
authors.initials: G
authors.lastname: Lorenzi-Filho
authors.forename: Gilberto G S
authors.initials: GG
authors.lastname: Formigoni
authors.forename: Michel B
authors.initials: MB
authors.lastname: Cahali
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D003094:Collagen / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D008297:Male; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D008875:Middle Aged; D010609:Pharyngeal Muscles / Q000378:metabolism* / Q000473:pathology*; D011509:Proteoglycans / Q000378:metabolism; D020181:Sleep Apnea, Obstructive / Q000378:metabolism* / Q000473:pathology*; D055815:Young Adult
chemical_list: D005353:Fibronectins; D011509:Proteoglycans; D003094:Collagen; D020778:Matrix Metalloproteinase 2; D020781:Matrix Metalloproteinase 1