Fig. 2.

Schematic diagram showing the progression of gastric wound healing. A: injury of the gastric epithelium either via chronic nonsteroidal anti-inflammatory drug (NSAID) use or inflammation results in ablation of the gastric epithelium and obvious ulcer margins. B: during the early stages of regeneration there is the emergence of the granulation tissue with infiltrating macrophages and the emergence of spasmolytic polypeptide-expressing metaplasia (SPEM). It is still unknown whether the SPEM glands at the ulcer margins arise from the transdifferentiation of the chief cells to a metaplastic phenotype. Reepithelialization (C) occurs before complete regeneration (D) of the gastric epithelium and transient expression of SPEM.