NOS-interacting protein (NOSIP) is increased in the colon of patients with Hirschsprungs's disease

Purpose Hirschsprung's associated enterocolitis (HAEC) is the most common cause of morbidity and mortality in Hirschsprung's disease (HSCR). Nitric oxide (NO) mediates intestinal homoeostasis and is inhibited by NOSIP, a modulator of NO production. We designed this study to investigate the expression of NOSIP in the colon of patients with HSCR. Methods We investigated NOSIP, endothelial NO synthase, and neuronal NO synthase expression in both the aganglionic and ganglionic regions of HSCR patients (n = 10) versus normal control colon (n = 10). Protein distribution was assessed by using immunofluorescence and confocal microscopy. Gene and protein expression were quantified using quantitative real-time polymerase chain reaction (qPCR), Western blot analysis, and densitometry. Main results qPCR and Western blot analysis demonstrate that NOSIP was significantly increased in the aganglionic and ganglionic colon compared to controls (p < 0.05). Confocal microscopy revealed a markedly increased expression of NOSIP in the colon epithelium of patients with HSCR compared to controls. Conclusion To our knowledge, we demonstrate for the first time the expression of NOSIP in the human colon. While NOSIP expression was increased in HSCR vs. non-HSCR patients, no significant difference was observed in patients with HAEC. The increased expression of NOSIP in the aganglionic and ganglionic bowel of HSCR may contribute to the development of enterocolitis by inhibiting local NO production in patients with Hirschsprung's disease.