Bowel dysfunction following pullthrough surgery is associated with an overabundance of nitrergic neurons in Hirschsprung disease

Abstract

PURPOSE Recent evidence suggests that patients with Hirschsprung disease (HD) have abnormal neurotransmitter expression in the ganglionated proximal colon. These alterations may cause persistent bowel dysfunction even after pullthrough surgery. We sought to quantify the proportion of nitrergic neurons in the ganglionic colon of HD patients and relate these findings to functional outcome. METHODS The proximal resection margin from 17 patients with colonic HD who underwent a pullthrough procedure and colorectal tissue from 4 age-matched controls were immunohistochemically examined to quantify the proportion of nitrergic neurons. The incidence of constipation, incontinence, and enterocolitis in HD patients was assessed retrospectively and correlated with the proportion of nitric oxide synthase (NOS) expressing neurons. Neuronal subtypes in the ganglionic colon of the Edrnb−/− mouse model of HD were also studied. RESULTS Mice with HD had a significantly higher proportion of NOS+ neurons in ganglionic colon than normal littermates (32.0 ± 5.6% vs. 19.8 ± 1.2%, p<0.01). Patients with HD also had significantly more NOS+ neurons than controls (18.4 ± 4.6% vs. 13.1 ± 1.9%, p<0.01). Patients who experienced constipation or enterocolitis postoperatively tended toward a higher proportion of NOS+ neurons (21.4 ± 3.9% vs. 17.1 ± 4.1%, p=0.06). Furthermore, patients with a proportion of NOS+ neurons above the median of all HD patients (18.3%) were significantly more likely to have constipation than those below the median (75% vs. 14%, p<0.05). CONCLUSION An overabundance of nitrergic neurons in the proximal resection margin is associated with HD and may predict bowel dysfunction following pullthrough surgery.

Gut microbiota-mediated Gene-Environment interaction in the TashT mouse model of Hirschsprung disease

“…Since the proportion of nitrergic neurons in these mice can be modulated by antibiotics-induced dysbiosis in a temporal manner (Figs 4 and 5), our work calls for detailed characterization of the distal ENS as a function of age and exposure to antibiotics not only in HSCR mouse models but also in human HSCR patients. Indeed, given that the proportion of nitrergic neurons is increased in HSCR patients as well 41 , this could have a direct influence on how these patients are being taken care of.…”

Semaphorin 3A controls enteric neuron connectivity and is inversely associated with synapsin 1 expression in Hirschsprung disease

“…The only current treatment is the operative removal of the segment devoid of ENS. However, recent studies suggested that the remaining bowel, although considered healthy, presents also ENS defects such as altered proportion of nitrergic neurons 27 , and that these defects could contribute to intestinal dysmotility that persists even after the surgery in many HSCR patients. In the current study, we determined the expression and distribution of Sema3A and its receptor NRP1 in the rat developing gut and studied the role of Sema3A on neuronal connectivity.…”

Analysis of enteric nervous system and intestinal epithelial barrier to predict complications in Hirschsprung’s disease

“…Only recently, Cheng et al observed changes in nNOS neurons in the proximal resection margin of HSCR patients. These changes were characterised by an increased proportion of nNOS myenteric neurons (nNOS +/Tuj + neurons) as compared to “controls” 13 . When expressed in proportion of neurons (normalised to the total number of neurons), we also observed an increased proportion of nNOS neurons in HSCR patients as compared to ARM patients.…”

“…Furthermore, in our study, the proportion of nNOS neurons was significantly reduced in HSCR patients with OS as compared to HSCR patients without OS. Cheng et al showed that the increased proportion of nNOS neurons in HSCR patients was retrospectively associated with non-stratified postoperative complications, including indifferently constipation, HAEC and faecal incontinence 13 . These differences between our studies result from the fact that they did not stratify patients according to the nature of postoperative complications (OS, HAEC or diarrhoea, that are discriminated by the proportion of nNOS neurons in our study).…”