Morphological changes of the enteric nervous system, interstitial cells of cajal, and smooth muscle in children with colonic motility disorders

OBJECTIVES:: To evaluate the relation between colonic manometry findings and the colonic enteric nervous system, interstitial cells of Cajal, and smooth muscle morphology. PATIENTS AND METHODS:: Colonic specimens from surgical resections or full-thickness biopsy specimens were assessed from a cohort of children who underwent colonic manometry before surgery. Colonic manometric patterns were subdivided into high-amplitude propagating contractions, low-amplitude propagating contractions, absence of contractions, and low-amplitude simultaneous contractions. Immunohistochemistry was performed to identify abnormalities in the enteric nervous system, interstitial cells of Cajal, and smooth muscle layers. RESULTS:: Study participants included patients with Hirschsprung disease (n ≤ 4), chronic intestinal pseudo-obstruction (n ≤ 1), and idiopathic intractable constipation (n ≤ 8). Thirty-seven ganglionic segments were studied. Abnormalities in myenteric plexus were recognized in segments of all manometry groups, and no differences could be identified when they were compared with segments with high-amplitude propagating contractions. All of the segments showed an abnormal interstitial cells of Cajal plexus, and no statistical difference could be identified between the 4 groups (n ≤ 0.08). Homogeneous expression of smooth muscle actin was observed in all of the segments. CONCLUSIONS:: In this cohort we were unable to classify specific manometric findings as reflective of myopathic or neuropathic abnormalities in patients with motility disorders. Caution should be used when predicting the type of neuromuscular disorder based on colonic manometry.