Objective: Evaluate the hypothesis that the same pepsinogen C molecule produced in the stomach is also produced by the lung.
Patients and Methods: Pulmonary and gastric tissues collected postmortem were immunohistochemically stained for pepsinogen C and pepsinogen A.
Results: Sixteen patients with diverse causes of death were evaluated. Gestational age at birth ranged between 21 and 37 weeks. Pepsinogen A was detected in 12 of the 13 stomach sections, mainly in the chief cells, but not in any lung sections. Pepsinogen C was detected in all stomach sections in chief and mucus cells and in 9 of the 16 lung sections, mainly in type II pneumocytes. Pepsinogen C was not detected in the 3 lung cases with a gestational age <23 weeks.
Conclusions: 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.