Epidermal growth factor and transforming growth factor-alpha: role in protection and healing of gastric mucosal lesions.

The maintenance of the integrity of the gastrointestinal mucosa and the repair of acute and chronic mucosal lesions are under the influence of various growth factors, especially epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha). EGF originates mainly from salivary glands, whereas TGF-alpha is released locally in the gastric mucosa, particularly when the mucosa is exposed to topical irritants. EGF and TGF-alpha have similar spectra of biological activity, which include the stimulation of the restitution and proliferation of mucosal cells, gastroprotection, vasodilatation, gastric adaptation to noxious substances, healing of acute and chronic lesions and inhibition of gastric acid secretion. Accumulation of EGF in the ulcer area as a result of excessive production by ulcer-associated new cell lineages contributes together with overexpression of EGF receptors in the ulcer area to the migration of cells from the ulcer margin and formation of granulation tissue and microvessels (angiogenesis) during the ulcer healing process.