Epithelial restitution and wound healing in inflammatory bowel
disease.
World J Gastroenterol. 2008 Jan 21;14(3):348-53.
Inflammatory bowel disease is characterized by a chronic
inflammation of the intestinal mucosa. The mucosal epithelium of
the alimentary tract constitutes a key element of the mucosal
barrier to a broad spectrum of deleterious substances present
within the intestinal lumen including bacterial microorganisms,
various dietary factors, gastrointestinal secretory products and
drugs. In addition, this mucosal barrier can be disturbed in the
course of various intestinal disorders including inflammatory
bowel diseases. Fortunately, the integrity of the gastrointestinal
surface epithelium is rapidly reestablished even after extensive
destruction. Rapid resealing of the epithelial barrier following
injuries is accomplished by a process termed epithelial
restitution, followed by more delayed mechanisms of epithelial
wound healing including increased epithelial cell proliferation
and epithelial cell differentiation. Restitution of the intestinal
surface epithelium is modulated by a range of highly divergent
factors among them a broad spectrum of structurally distinct
regulatory peptides, variously described as growth factors or
cytokines. Several regulatory peptide factors act from the
basolateral site of the epithelial surface and enhance epithelial
cell restitution through TGF-beta-dependent pathways. In contrast,
members of the trefoil factor family (TFF peptides) appear to
stimulate epithelial restitution in conjunction with mucin
glycoproteins through a TGF-beta-independent mechanism from the
apical site of the intestinal epithelium. In addition, a number of
other peptide molecules like extracellular matrix factors and
blood clotting factors and also non-peptide molecules including
phospholipids, short-chain fatty acids (SCFA), adenine
nucleotides, trace elements and pharmacological agents modulate
intestinal epithelial repair mechanisms. Repeated damage and
injury of the intestinal surface are key features of various
intestinal disorders including inflammatory bowel diseases and
require constant repair of the epithelium. Enhancement of
intestinal repair mechanisms by regulatory peptides or other
modulatory factors may provide future approaches for the treatment
of diseases that are characterized by injuries of the epithelial
surface.