title: Reassessment of the importance of mucins in determining sputum properties in cystic fibrosis.
abstract: BACKGROUND
  There is conflicting evidence about the importance of airway mucins (MUC5AC and MUC5B) in determining physical properties of sputum in cystic fibrosis (CF). We studied the effects of endogenous degradation of mucins on CF sputum elasticity and apparent mucin concentrations.
  
  
  METHODS
  Elastic shear moduli (G') and mucin concentrations in sputum of 12 CF patients were measured before and after incubation at 37°C for 60min.
  
  
  RESULTS
  G' fell from a median of 5.98 to 4.70Pa (p=0.01). There were significant falls in MUC5AC (8.2 to 5.2μg/ml, p=0.02) and MUC5B (17.3 to 12.5μg/ml, p=0.02) over the same period, and associated decrease in molecular weight and size.
  
  
  CONCLUSIONS
  Sputum is not inert and degradation reduces apparent mucin concentrations and sputum elasticity. Even if care is taken to process samples rapidly, sputum may therefore differ from secretions retained in airways. Previous studies may have underestimated the role of mucins in CF sputum.
authors: Manchester Adult Cystic Fibrosis Centre, University Hospital South Manchester, Manchester M23 9LT, UK; Institute of Inflammation and Repair, Education and Research Centre, University Hospital South Manchester, Manchester M23 9LT, UK; Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK. Electronic address: alexander.horsley@manchester.ac.uk.
authors: Alex
authors: A
authors: Horsley
authors: Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK.
authors: Karine
authors: K
authors: Rousseau
authors: Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK.
authors: Caroline
authors: C
authors: Ridley
authors: Manchester Adult Cystic Fibrosis Centre, University Hospital South Manchester, Manchester M23 9LT, UK; Institute of Inflammation and Repair, Education and Research Centre, University Hospital South Manchester, Manchester M23 9LT, UK.
authors: William
authors: W
authors: Flight
authors: Manchester Adult Cystic Fibrosis Centre, University Hospital South Manchester, Manchester M23 9LT, UK; Institute of Inflammation and Repair, Education and Research Centre, University Hospital South Manchester, Manchester M23 9LT, UK.
authors: Andrew
authors: A
authors: Jones
authors: Biological Physics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.
authors: Thomas A
authors: TA
authors: Waigh
authors: Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK.
authors: David J
authors: DJ
authors: Thornton
mesh_terms: D000293:Adolescent; D000328:Adult; D003550:Cystic Fibrosis / Q000378:metabolism*; D004548:Elasticity; D005260:Female; D006801:Humans; D008297:Male; D008970:Molecular Weight; D055271:Mucin 5AC / Q000737:chemistry / Q000378:metabolism*; D055257:Mucin-5B / Q000737:chemistry / Q000378:metabolism*; D011014:Pneumonia / Q000378:metabolism*; D059748:Proteolysis; D012212:Rheology; D013147:Spirometry; D013183:Sputum / Q000737:chemistry / Q000378:metabolism*; D055815:Young Adult
chemical_list: C524678:MUC5AC protein, human; C524578:MUC5B protein, human; D055271:Mucin 5AC; D055257:Mucin-5B
keywords: Cystic fibrosis; Lung inflammation; Mucin; Proteolysis