Impedance baseline measurements might be used to evaluate the status of the oesophageal mucosa and to study the role of the impaired mucosal integrity in acid-induced heartburn in healthy volunteers and in patients with GORD.

Acid gastro-oesophageal reflux (GOR) and gastric aspiration have been labelled as risk factors for chronic rejection bronchiolitis obliterans syndrome (BOS) after lung transplantation (LTx). The present study aimed to further characterise GOR (both acid and nonacid) and the degree of gastric aspiration in LTx recipients both with and without BOS.Impedance-pH recordings were used for GOR detection. Pepsin and bile acid levels were measured in bronchoalveolar lavage fluid (BALF).A total of 48% of patients had increased GOR, of which 27% had exclusively increased nonacid reflux. Cystic fibrosis patients had the highest prevalence of GOR. Pepsin was found in BALF of all patients and bile acids in BALF of 50% of the patients. Patients with BOS had neither increased GOR nor elevated pepsin in BALF. However, 70% of the patients with BOS had bile in BALF compared with 31% of stable patients. Proton pump inhibitor (PPI) treatment reduced acid reflux but did not affect nonacid reflux. Moreover, pepsin and bile levels in BALF were not reduced by PPI.One-half of the lung transplant patients had increased reflux, and nonacid reflux was common. Gastric aspiration occurred in most lung transplant patients. Pepsin was a more general marker and bile acids a more specific marker that might be associated with bronchiolitis obliterans syndrome. Proton pump inhibitor treatment did not prevent nonacid reflux and gastric aspiration.

Experimental short exposure of the oesophageal mucosa to solutions with a bile acid concentration and acidity similar to that observed in the gastric contents of patients with NERD or ERD, and who are taking PPIs, may impair oesophageal mucosal integrity and even induce dilated intercellular spaces. Such a situation could, theoretically, underlie the occurrence and/or persistence of symptoms in these patients.

The human oesophageal mucosa is very sensitive to continuous exposure with acidic and weakly acidic solutions. In spite of the presence of intraluminal acid and DIS, healthy subjects did not experience heartburn, suggesting that NERD patients should have other critical factors underlying their symptoms.

SUMMARYBackground Symptoms, oesophageal pHmetry and proton pump inhibitor treatment are used for diagnosing gastro-oesophageal reflux-related cough. Weakly acidic reflux is now increasingly associated with reflux symptoms such as regurgitation or chest pain.

Increased GOR is prevalent in CF and not secondary to cough. Acid GOR is common, but weakly acidic GOR may also occur. CF patients have a high risk of aspiration and reflux seems to be associated with more cough and poorer lung function. Outcome studies with intense anti-reflux therapy are needed to confirm the deleterious role of reflux in CF progression.

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Background Approximately half of all patients who underwent a lung transplantation suffer from bronchiolitis obliterans syndrome (BOS), the clinical correlate of chronic rejection, within 5 years after transplantation. This prevalence is much higher than for other solid organ transplantations, possibly due to the lung's direct contact with the environment. The authors assessed the association between proximity of the home to major roads and BOS and mortality in a cohort of patients after lung transplantation. Methods The authors calculated hazard ratios for BOS and mortality in relation to proximity of the home to major roads, adjusting for relevant covariables, in 288 patients after lung transplantation at the Leuven University Hospital between 1997 and 2009 and with follow-up until August 2009. Inflammatory parameters in plasma and bronchoalveolar lavage were assessed in 207 patients. Results During follow-up, 117 (41%) patients developed BOS and 61 (21%) died. Patients who lived within 171 m of a major road (lowest tertile) were 2.06 (95% CI 1.39 to 3.05) times more likely to develop BOS and 2.20 (1.25 to 3.86) times more likely to die than patients living farther away. The adjusted hazard ratios of BOS and mortality were 0.57 and 0.72 for each 10-fold increase in distance from major roads. Proximity to a major road was inversely associated with plasma C-reactive protein levels, neutrophil percentage and interleukin-6 concentration in bronchoalveolar lavage. Conclusion Traffic-related air pollution appears to constitute a serious risk of BOS and mortality after lung transplantation.