Epithelial Functions of the Residual Bowel After Surgery for Necrotising Enterocolitis in Human Infants

ABSTRACT Objectives: Information on epithelial functions of the residual small or colonic bowel after resection for necrotising enterocolitis (NEC) in human infants is scarce. Our aim is to evaluate epithelial functions in the intestinal resection margins of tissue obtained at bowel resection for acute NEC and consecutive stoma closure. Materials and Methods: Epithelial morphology, proliferation, and protein expression were (immuno)histochemically studied. Results: Acute NEC was associated with severe and mild epithelial damage varying from epithelial loss to fairly unaffected epithelium. Epithelial proliferation was increased both at acute NEC and at stoma closure. In acute NEC, lactase, glucose transporter‐2 and ‐5 expression was down‐regulated in severely affected epithelium, whereas sucrase‐isomaltase and intestinal fatty acid binding protein expression was maintained. Goblet cells continued to express mucin 2 and trefoil factor 3, however, their numbers were decreased. Moreover, in acute NEC, Paneth cells were weakly lysozyme positive and were reduced in number. At stoma closure, expression of the above cell type–specific markers had completely been re‐established. Conclusions: Residual bowel after resection for acute NEC shows a disturbed epithelial proliferation/differentiation balance. Acute NEC was associated with downregulation of distinct enterocyte‐specific proteins. Because of goblet cell and Paneth cell loss in acute NEC, mucosal barrier, and defense functions may be impaired.