Effect of pirenzepine on gastric endocrine cell kinetics during lansoprazole administration

Pathological effects of drugs on the gastrointestinal tract: a review

Drug-induced injury of the gastrointestinal (GI) tract is increasingly common but generally under-recognized. Although there is an overwhelming number of drugs that are associated with adverse GI effects, there is a limited number of characteristic injury patterns that should prompt consideration of drug-induced GI pathology. These include the following: erosions, ulcers, and strictures; crystal deposition; parietal cell changes; reactive gastropathy; pseudodysplastic changes; microscopic colitis; infectious or necrotizing enterocolitis; ischemic colitis; focal active colitis; and increased epithelial apoptosis. This article reviews morphological and pathophysiological features of some of the more common and pathologically recognizable drug-related injury patterns and provides a practical guide for the recognition and diagnosis of drug-induced pathology in the upper and lower GI tract.

Mechanism of gastric mucosal proliferation induced by gastrin

Gastrin has a potent trophic effect on gastric fundic mucosa. When serum concentrations of gastrin are elevated, proliferation of both the progenitor cells in the glandular neck zone and enterochromaffin-like (ECL) cells in the bottom of the glands is stimulated. Because ECL cells have gastrin receptors, their proliferation is directly stimulated by gastrin. However, because the proliferation of progenitor cells cannot be directly stimulated (so far there has been no gastrin receptor demonstrated on these proliferating cells), some indirect mechanisms must be involved. Enterochromaffin-like and parietal cells are only two types of cells that have demonstrated a strong gene expression of the gastrin receptor. Furthermore, they secrete several growth factors, such as Reg protein, heparin-binding epidermal growth factor-like growth factor (HB-EGF) and amphiregulin (AR). Reg protein production by ECL cells, as well as HB-EGF and AR production by parietal cells, is stimulated by gastrin and these growth factors are potent trophic agents of progenitor cells in the neck zone of the gastric fundic mucosa. Accordingly, gastrin may stimulate the proliferation of gastric mucosal cells indirectly via these growth factors in addition to its direct trophic effect on ECL cells.