CHEST Guidelines-Pepsin

Pepsin_chest
Pdf Summary
The document primarily discusses the role of pepsin as a biomarker and its involvement in gastroesophageal reflux disease (GERD). The focus is on examining the interactions between pepsin, acid, and mucosal injury, particularly its potential involvement in extra-esophageal mucosal injury and its relevance as a biomarker for reflux aspiration. <br /><br />In GERD, pepsin, the primary proteolytic enzyme, becomes active at low pH levels, contributing significantly to esophagitis. It has been used as a biomarker in gastric refluxate due to its consistent presence. However, its role is not entirely clear when found outside the gastrointestinal tract, such as in the oropharynx or tracheobronchial tree. The presence of pepsin in these areas suggests regurgitation or aspiration but doesn't directly correlate with epithelial damage.<br /><br />The article reviews a study by Hallal et al., which explored pepsin isoform presence in critically ill pediatric patients with mechanical ventilation. The study found universal presence of pepsin A in tracheal secretions among these patients, indicating gastric aspiration might contribute to pulmonary complications. However, the findings' pathophysiologic significance is debated since pepsin's activation requires an acidic environment not present in the tracheobronchial tree.<br /><br />The document stresses the distinction between pepsin A (stomach-specific) and pepsin C, which occurs in other organs too, highlighting the need for more specific biomarkers for GERD-related research. The study is deemed insightful, although its full clinical implications remain speculative. Further research is needed to clarify pepsin's role in GERD, particularly regarding its supraesophageal manifestations and potential use in guiding treatments for mechanically ventilated patients.
Keywords
pepsin
biomarker
GERD
gastroesophageal reflux
mucosal injury
reflux aspiration
pepsin A
tracheal secretions
gastric aspiration
mechanical ventilation