Detection of Pepsinogen in the Neonatal Lung and Stomach by Immunohistochemistry

Abstract

The same pepsinogen C molecule is produced in the stomach and in the lung. These findings potentially affect previous study results that used an enzymatic pepsin detection assay to evaluate for and associate gastroesophageal reflux disease with other morbidities.

Pepsin in saliva for the diagnosis of gastro-oesophageal reflux disease

“…There are several different isoforms of pepsin, most produced solely in the stomach, however, pepsin C may be produced by pneumocytes 34. Therefore non-specific pepsin assays may give false positive results.…”

Airway Pepsin Levels in Otherwise Healthy Surgical Patients Receiving General Anesthesia With Endotracheal Intubation

“…A second important consideration is that, unlike pepsinogen A, pepsinogen C has been identifi ed in extragastric 36 sites, including the lungs. [37][38][39] Specifi cally, it appears to be expressed by type 2 pneumocytes and is involved in surfactant B processing. 40 As such, it is plausible that the detection of pepsin in the lower airways, if not specifi c for pepsin A, may be due to the detection of pepsinogen C in pathologic states in which surfactant B expression has been increased.…”

Association between tracheal pepsin, a reliable marker of gastric aspiration, and head of bed elevation among ventilated neonates

“…Because pepsinogen C, a molecule produced by the stomach and the lung, where it is involved in the proteolytic processing of surfactant protein B, has functions similar to pepsinogen A, the precursor molecule of gastric pepsin, enzymatic methods used by other 5 to measure pepsin may be measuring not only pepsin but also the pepsinogen C being produced in the lung [20].…”