Regeneration Following Gastric Injury
144The gastric mucosa has a great potential to heal both superficial and deep mucosal lesions. The healing process of superficial lesions (restitution) is rapidly achieved within minutes or hours predominantly by cell migration. In contrast, healing of deep lesions occurs over days to weeks since it requires formation of new mesenchymal and epithelial structures. The time relationship of this healing process conforms to an organic decay curve whereby a maximum healing phase is interspaced between an initial and late slow healing phase. While it is well established that luminal acid can delay the healing of both superficial and deep lesions, conflicting views exist as to which factors accelerate healing. Trophic effects of both gastrin and epidermal growth factor have an accepted potential to enhance healing of deep lesions. In contrast, evidence is accumulating that prostaglandins cannot accelerate restitution or healing of deep lesions by means other than inhibition of gastric acid.
The gastrointestinal mucosa, particularly that of the stomach, has a great potential to repair both superficial and deep epithelial lesions. While it has long been recognized that regeneration by mitotic reproduction from proliferating stem cells is an important factor in this healing process, it has been shown more recently that superficial lesions can rapidly be repaired by migration of underlying cells from the gastric pits. The latter process must be differentiated from the much slower evolution of wound healing (Table 1).