P2D330: Impairment of Intestinal Regeneration in the Colon of Children with Hirschsprung’s Associated Enterocolitis

Background: Hirschsprung’s (HD) associated enterocolitis (HAEC) is a common and serious complication in children with Hirschsprung’s disease. We previously demonstrated decreased intestinal epithelial stem cells due to dysfunctional Wnt pathway in a mouse model of HAEC. We hypothesize that intestinal regeneration is impaired in the colon of children with HAEC.

Methods: Ethical approval for this study was obtained from the Research Ethics Board of two children’s hospitals (SHERLL # 2019049; REB # 1000056881). The patients were diagnosed with HAEC prior to surgery, based on their clinical signs and symptoms, according to the Guidelines of the American Pediatric Surgical Association Hirschsprung Disease Interest Group, and were treated with rectal irrigations and intravenous antibiotics. Pull-through operations were carried out after HAEC subsided clinically. Intestinal tissue of 6 HAEC patients and 4 HD patients with no enterocolitis were collected from the colon resected at the pull-through operation. Epithelial injury was studied by histological staining. Intestinal regeneration was assessed by immunostaining of epithelial cellular proliferation marker Ki67, intestinal stem cell marker Lgr5, and β-catenin. Statistical analysis was performed by t-tests.

Results: Colonic epithelial injury was observed in the distal dilated ganglionic colon and transition zone of HAEC patients but not in HD patients (Figure A). Both Ki67 and Lgr5 staining showed a decreased expression in the distal ganglionic and transitional colon (Figure B, C) compared to HD patients. Activated nuclear-translocated β-catenin at the bottom of crypts was significantly decreased in the distal ganglionic and transition zone in HAEC patients (Figure D).

Conclusion: HAEC epithelial injury is characterized by decreased intestinal stem cells and regeneration in the distal ganglionic and transitional colon. This pathophysiological phenomenon supports the development of Hirschsprung’s associated enterocolitis before the functional obstruction is eliminated and the recurrence rate of this complication.