Role of GDNF, GFRα1 and GFAP in a Bifidobacterium-Intervention Induced Mouse Model of Intestinal Neuronal Dysplasia

ObjectiveTo investigate the effects of glial cell-derived neurotrophic factor (GDNF), GDNF family receptor alpha 1 (GFRα1), and glial fibrillary acidic protein (GFAP) on colonic motility in a mouse model of intestinal neuronal dysplasia by intervention with Bifidobacterium and to explore the influence of Bifidobacterium on enteric glial cells (EGCs).MethodsWestern blotting and qRT-PCR were employed to detect the expression of GFRα1 and GFAP in colonic tissues of mice with or without Tlx2 mutations, and ELISA was used to detect the expression of GDNF in serum. IHC was used to detect the appearance of the ganglion cells. Subsequently, Tlx2 homozygous mutant (Tlx2−/−) mice were treated with Bifidobacterium. Colonic motility was measured before and after intervention by measuring the glass bead expelling time. The variations in abdominal circumference and GDNF, GFRα1, and GFAP expression were measured. In addition, 16SrRNA gene sequencing was performed to detect the abundance of the intestinal microbiota.ResultsThe mRNA and protein expression of GFRα1 and GFAP was decreased in the colonic tissues of Tlx2−/− mice and GDNF expression was decreased in serum compared with Tlx2+/− and WT mice. After confirming the colonization of Bifidobacterium by 16S rRNA gene sequencing, the expelling time and abdominal distension were ameliorated, and the expression of GFAP, GDNF, and GFRα1 was increased.ConclusionsThe expression of GDNF, GFRα1, and GFAP is associated with colonic motility. The altered expression of EGC-related factors suggested that Bifidobacterium may be involved in the EGC activation process. The amelioration of IND symptoms after intervention with Bifidobacterium prompted the elicitation of adjuvant therapy.

Isolated Intestinal Neuronal Dysplasia- Type B of Ileum: a Rare Occurrence

Background: Intestinal neuronal dysplasia type B in the gastrointestinal tract is a rare occurrence and may occur alone or in combination with Hirschsprung disease. Distal colon seems to be frequent site for isolated IND-B cases, however small bowel involvement is scarcely reported. Case presentation: We report a case of 9 years old boy presenting with features of intestinal pseudo-obstruction for 5 years. Exploratory laparotomy revealed narrowed distal ileum with huge proximal dilatation. Histopathology of the resected terminal ileum revealed giant submucosal ganglion, hyperplastic submucosal nerves and ectopic ganglion cells in the lamina propria suggestive of IND-B.Conclusions: Although IND-B involving ileum is a rare occurrence, suspicion should be kept in cases of intestinal obstruction with minimal response to conventional treatment.

Identification of potential molecular pathogenesis mechanisms modulated by microRNAs in patients with Intestinal Neuronal Dysplasia type B

This study proposed to determine global microRNA (miRNA) expression and miRNA-regulated pathways in Intestinal Neuronal Dysplasia type B (IND-B). Fifty patients (0–15 years old) with IND-B were included in the study. Peripheral blood samples were collected from all 50 patients and from 10 healthy asymptomatic children (controls). Rectal biopsies were collected from 29/50 patients; biopsy tissues were needle microdissected to isolate the different intestinal layers, for molecular analysis. Global miRNA expression was determined using TaqMan arrays. Correlation analysis between miRNA expression in plasma and biopsy samples as well as among tissues derived from the distinct intestinal layers was performed. Computational approaches were used for miRNA target prediction/identification of miRNA-regulated genes and enriched pathways biologically relevant to IND-B pathogenesis. miRNAs were statistically significantly deregulated (FC ≥ 2 and p ≤ 0.05) in submucosal and muscular layers: over-expressed (miR-146a and miR-146b) and under-expressed (miR-99a, miR-100, miR-130a, miR-133b, miR-145, miR-365, miR-374-5p, miR-451). Notably, let-7a-5p was highly over-expressed in patient plasma compared to healthy controls (FC = 17.4). In addition, miR-451 was significantly under-expressed in both plasma and all biopsy tissues from the same patients. Enriched pathways (p < 0.01) were axon guidance, nerve growth factor signalling, NCAM signalling for neurite out-growth, neuronal system and apoptosis. miRNA expression is deregulated in the submucosa and muscular layers of the rectum and detected in plasma from patients with IND-B. Biologically enriched pathways regulated by the identified miRNAs may play a role in IND-B disease pathogenesis, due to the activity related to the neurons of the enteric nervous system.

Intestinal Neuronal Dysplasia Type B: Timely Diagnosis and Management

A 23-year-old female presented to the emergency department with abdominal pain and constipation. She reported an extensive history of constipation. Imaging showed distended bowel without an obstruction. During laparotomy, no obvious mechanical cause was found and a total colectomy was performed. Gross examination of the colectomy specimen showed cobblestoning in a 10-cm portion of the colon. Microscopic examination demonstrated hypoganglionosis of the myenteric plexus, hyperganglionosis of Auerbach’s plexus, and “giant ganglia.” This case met the 2006 Meier-Ruge criteria and diagnosis of intestinal neuronal dysplasia (IND) was established. IND was first described in 1971. The frequency of IND varies widely due to lack of consensus of diagnostic criteria and has a geographic distribution with the highest rates in Europe, which correlates to published research in this region. Diagnostic criteria are controversial and require standardization. Meier-Ruge suggests a quantitative analysis of the number of ganglion cells in the submucosal plexuses and the identification of at least 20% giant ganglia with at least 8 neurons each, in 25 analyzed ganglia. More recent diagnostic criteria are conservative with differences, including (1) elimination of increased AChE-positive nerve fibers around submucosal blood vessels, (2) stipulation that a giant ganglion contains more than 8 ganglion cells, (3) the requirement that more than 20% of at least 25 ganglia be giant ganglia, and (4) diagnostic exclusion of patients <1 year. Clinical management is also controversial. Schimpl et al reported satisfactory results in 80% of 105 patients treated with dietary changes, cisapride, and laxatives with a median 7.2 years follow-up. Since colonic peristalsis is impaired by dysganglionosis, subtotal colectomy procedures have been widely successful. Clinicians should be mindful of IND in patients with a history of chronic constipation with abdominal pain and nonspecific imaging, as timely diagnosis can spare the patient from total colectomy and improve quality of life.