Fundic gland cysts in Atp4a-/- mice mimic fundic gland polyps in humans.

BACKGROUND Innumerable fundic gland polyps (FGPs) (that is massive FGP polyposis) may be found in the human stomach. Innumerable fundic gland cysts (FGCs) develop in mice lacking the gene Atp4a (Atp4a((-/-))), that encodes the enzyme ATPase. The aim was to monitor the evolution of FGCs in Atp4a((-/-)) mice. MATERIALS AND METHODS Six pairs (male-female) of Atp4a((-/-)) mice, 8, 12 and 20 months old, were investigated. Wild-type Atp4a((+/+)) mice were used as controls. RESULTS In Atp4a((-/-)) female mice, the mucosal thickness increased both at 8 months (943+/-72 mm) (p<0.02) and at 12 months (p<0.0008) and even further at 20 months (p<0.0001). The FGC area was 13.183+/-7.218 mm(2) at 12 months and 73.361+/-50.591 mm(2) at 20 months (p<0.0008). FGCs in Atp4a((-/-)) mice were lined by parietal cells, mucous pit-foveolar cells and chief cells, thus mimicking FGPs in humans. CONCLUSION Older female Atp4a((-/-)) mice developed innumerable FGCs, a phenomenon very similar to massive FGPs seen in humans. In the light of these similarities, the Atp4a((-/-)) mouse emerges as a suitable animal model to investigate the series of events taking place during the evolution of FGPs in humans.