Background: Little is known about the early development of the gastric acid secretion in human neonates. The purpose of this study was to examine the early development of gastric H,K-adenosine triphosphatase (ATPase) by analyzing human gastric biopsy specimens.
Methods: Eighty-eight neonates from week 25 to week 42 of gestation who were treated in a neonatal intensive care unit underwent gastroscopy with biopsy specimens obtained from the corpus. The expression of gastric H,K-ATPase protein in the gastric biopsy specimens was assessed by Western blot analysis, using an antibody directed against the gastric H,K-ATPase. The amount of H,K-ATPase expressed was compared with age, gender, clinical factors, diseases, and the macroscopic and histologic findings at endoscopy.
Results: The expression of human gastric H,K-ATPase increased significantly with gestational age. There was a significant increase in the expression of gastric H,K-ATPase during the first 82 days after birth. Boys had a significantly higher expression of gastric H,K-ATPase than girls did, when it was adjusted for gestational and postnatal age. Neither the clinical features nor treatments showed significant correlations with the expression of human gastric H,K-ATPase when controlling for gestational and postnatal age.
Conclusions: This study shows that human gastric H,K-ATPase is expressed from week 25 of gestation, which agrees with earlier findings of gastric pH in preterm infants. The amount of enzyme expressed increases with gestational and postnatal age. The authors speculate that the susceptibility to gastric lesions seen in neonates is not related to the amount of H,K-ATPase. However, studies elucidating the ontogeny of gastric mucosal defense mechanisms are warranted.