YF476 differs from the
proton pump inhibitor (PPI)
esomeprazole in mode of action by antagonizing the type 2 receptor of
cholecystokinin/
gastrin (CCK-2R).
YF476 protection against
diclofenac-induced
gastric ulcers was compared to
esomeprazole and correlated with plasma levels of
hormones related to gastric pH (
gastrin,
ghrelin, and
somatostatin), gastric gene expression of these
hormones, their receptors, and
inducible nitric oxide synthase (iNOS).
YF476 or
esomeprazole pretreatments were followed by
diclofenac. Four hours later, gastric tissue was excised and analyzed for
ulcer index. An intragastrically implanted
Bravo capsule measured pH for 5 days during
YF476 plus
pentagastrin treatment. Changes in gene expression were assayed for
gastrin,
ghrelin, and
somatostatin; their receptors; and iNOS.
YF476 acutely (within 4 h) protected against
diclofenac-induced
gastric ulcers equivalent to
esomeprazole. Gastric pH recorded during 5 days in the presence of
pentagastrin was 1.83 (±0.06).
YF476 raised pH to 3.67 (±0.09) and plasma
ghrelin,
gastrin, and
somatostatin increased.
YF476 increased gene expression of
somatostatin receptor and
gastrin, while
ghrelin receptor decreased; transcripts coding
ghrelin,
somatostatin, and CCK-2R remained unchanged. In the presence of
diclofenac,
esomeprazole increased expression of all these transcripts and that of iNOS, while
YF476 yielded only decreased CCK-2R and increased iNOS transcripts.
YF476 is a potential new preventative treatment for patients at risk of nonsteroidal antiinflammatory
drug (
NSAID)-induced ulceration. Gastric gene expressions of
ghrelin,
gastrin, and
somatostatin and their receptors differ between
esomeprazole and
YF476. Despite these differences and different modes of action to raise gastric pH, both drugs acutely increase iNOS, suggesting iNOS expression parallels pH.