Alterations of Cajal cells in patients with small bowel atresia

Interstitial cells of Cajal (ICC) are regarded as the pacemaker cells of the gastrointestinal tract. There are some well-designed studies investigating the structure and function of ICC subsequent to experimentally induced intestinal obstructions. However, it remains unclear whether reduction of number of ICC primarily leads to mechanical obstruction of the bowel such as seen in intestinal atresia. We aimed to investigate the number of ICC in proximal and distal parts of the atresias of patients with small bowel atresia.

Twenty-one patients (13 male and 8 female; median age, 3 days; median gestation age, 38 weeks) with jejunal or ileal atresia underwent primary repair between 2001 and 2009. The demographic data were reviewed. The specimen of the distal and proximal parts of the atretic segments was investigated according to presence and number of ICC in the myenteric plexus using immunohistochemical methods. The jejunum segments of 14 newborns who died from causes other than bowel disease were examined as a control. Scoring and count systems were developed for the evaluation of ICC. A continuous layer of CD-117 immunoreactive Cajal cells around the myenteric plexus was scored as 3, whereas discontinuous and diminished Cajal cells were scored as 2. Few and sparse Cajal cells around the myenteric ganglia and in the muscle layer were scored as 1. If there was no Cajal cell at all, it was scored as zero. In addition, the number of ICC per field was counted. The scores and the numbers of ICC per field were compared in patients with small bowel atresia and control group.

All patients but one survived. One patient was lost because of congenital cardiac anomalies. The median score of control subjects was 3 (range, 1-3). Both the proximal and distal segments of the atretic bowel had a median score of 1 in patients with atresia. Twenty patients' score of proximal (95%) and 19 patients' score of distal bowel segment (90%) had an ICC score of 2 or less. Only 1 control subject (7%) had an ICC score of less than 2. Results were statistically significant in controls and patients. The mean number of ICC in the control group was 5.36 +/- 2.36; in distal segments of patients with atresia, it was 1.03 +/- 1.4; and in proximal segments, it was 0.82 +/- 1.56. The difference between the control group and the patients was statistically significant (P < .05).

We demonstrated a remarkable decrease of ICC in small bowel wall of patients with intestinal atresia; but we could not show whether the reduction of ICC is a primary event, which also participates in the pathogenesis of intestinal atresia, or whether the mechanical obstruction caused by any unknown etiology (eg, ischemia) leads to decrease in number of ICC.