Title: W1060 Bile Acids in Sputum of Patients With Cystic Fibrosis
Abstract: In prior studies we found that the airway mucus response to esophageal acidification was not mediated by the vagus nerves.AIM: To determine whether the airway mucus response to esophageal acidification is mediated by a local pathway.METHODS: Cats (N=23) were anesthetized with alpha-chloralose (50mg/kg, IP).The esophagus was cannulated at both ends, a gastrostomy was formed to allow drainage of gastric contents, and the femoral vein was cannulated for hydration (0.9% NaCl).In all studies, the esophagus was perfused with either 0.1 PBS or 0.1N HCl at 1ml/min and at the end of the study the trachea was removed and placed in formalin for later histological analysis of mucus content.The effects of the control perfusion (CP), i.e.HCl for 30min followed by PBS for 30 min, on tracheal mucus was tested at different time intervals (N=5) or after 60 minutes (N=5).In 7 cats the effects of the CP on tracheal mucus was tested after cutting the connectives between the cervical esophagus and trachea.In 6 cats the effects of the CP selectively applied to the thoracic esophagus on tracheal mucus was tested.The fixed tracheal samples were paraffin embedded, sectioned at 5 u, and stained for mucus using 1% Alcian Blue and PAS.The % area of the tracheal mucosa and submucosa containing mucus was quantified using an Olympus BH-2 microscope, Spot RT color digital camera, and Image J image analysis software.Differences in mucus content were determined using paired Student's t-test.RESULTS: We found that the mucus content of the cervical trachea maximizes at 60 min post the CP and at this time the mucosa contained a greater % of mucus (cervical:15.4±4%,thoracic:16.5±4%)than the submucosa (cervical:11.6±1%,thoracic: 12.9±2.5%).Selective administration of the CP to the thoracic esophagus, selectively increased (mucosa: cervical (8.6±2%) vs thoracic (16.1±3%); submucosa: cervical (11±1%) vs thoracic (16.6±2.3%);P<0.05) thoracic tracheal mucus content.On the other hand, cutting the connectives between the cervical esophagus and the trachea prevented the increase in cervical tracheal mucus content (mucosa: cervical (7.2±1%) vs thoracic (10.4±1%); submucosa: cervical (10±2%) vs thoracic (17±4%); P<0.05) caused by the CP.CONCLUSION: The airway mucus response to esophageal acidification is mediated by a local neural pathway within the esophago-tracheal connectives W1058