Background: Subpopulations of c-Kit immunopositive cells in the muscle coat of the gastrointestinal tract are considered pacemaker cells and have been investigated in human tissue relating to motility disorder. However, the morphology of c-kit immunopositive cells in intact human tissue is still unclear.
Methods: The authors studied the distribution of c-Kit immunopositive cells in the normal human colon and their cellular configuration by confocal microscopy on whole-mount preparations. The authors then compared them with six cases of Hirschsprung's disease (HD; two of short segment aganglionosis, three of extensive aganglionosis, and one of total aganglionosis).
Results: In the normal colon regional differences were found in the distribution of c-Kit immunopositive cells. The population in the muscle layers and at the submucosal border was larger in the anal part than in the oral part. Accumulation of positive cells at the myenteric plexus level was prominent only at the descending colon. In the descending colon of HD the authors could not demonstrate any differences in c-Kit immunopositive cells on aganglionic segments compared with the corresponding area of intact tissue.
Conclusion: More attention must be paid to these regional differences of distribution, and identical regions of affected and unaffected bowels must be compared when discussing the relation between the abnormality of c-Kit-positive cells and motility disorders including HD.