Obstructed defecation-an enteric neuropathy? An exploratory study of patient samples

Age-associated changes in lineage composition of the enteric nervous system regulate gut health and disease

The enteric nervous system (ENS), a collection of neural cells contained in the wall of the gut, is of fundamental importance to gastrointestinal and systemic health. According to the prevailing paradigm, the ENS arises from progenitor cells migrating from the neural crest and remains largely unchanged thereafter. Here, we show that the lineage composition of maturing ENS changes with time, with a decline in the canonical lineage of neural-crest derived neurons and their replacement by a newly identified lineage of mesoderm-derived neurons. Single cell transcriptomics and immunochemical approaches establish a distinct expression profile of mesoderm-derived neurons. The dynamic balance between the proportions of neurons from these two different lineages in the post-natal gut is dependent on the availability of their respective trophic signals, GDNF-RET and HGF-MET. With increasing age, the mesoderm-derived neurons become the dominant form of neurons in the ENS, a change associated with significant functional effects on intestinal motility which can be reversed by GDNF supplementation. Transcriptomic analyses of human gut tissues show reduced GDNF-RET signaling in patients with intestinal dysmotility which is associated with reduction in neural crest-derived neuronal markers and concomitant increase in transcriptional patterns specific to mesoderm-derived neurons. Normal intestinal function in the adult gastrointestinal tract therefore appears to require an optimal balance between these two distinct lineages within the ENS.

Significance of searching for ganglia in the terminal rectum/fistula of complex anorectal malformations: Related to defecation function

Background

The need to search for ganglia in the terminal rectum/fistula of complex anorectal malformations (ARMs) remains controversial. This study aims to evaluate the relationship between ganglia absence in the terminal rectum/fistula and defecation function after anoplasty.

Methods

A retrospective review of patients who received anoplasty for treating male imperforate anus with rectobulbar (RB)/rectoprostatic (RP) fistulas at a tertiary pediatric hospital was conducted with registered demographic data, imaging study results, and information on the terminal rectum/fistula specimen (excision extension and pathological findings). According to the pathological findings, patients were divided into Groups 1 (ganglia absence) and 2 (ganglia presence). Furthermore, the postoperative defecation function was evaluated using various rating scale questionnaires. Statistical analysis was performed using SPSS 22.0.

Results

Of the 62 patients, 18 (29.0%) showed ganglia absence in the terminal rectum/fistula. By analyzing the imaging data, spinal anomalies and spinal cord anomalies were found in 30.6% (19/62) and 56.5% (35/62) of patients, respectively. Baseline information was comparable between Groups 1 and 2 (P > 0.05). For defecation function, there were no significant differences in Kelly scores between the two groups (4.0 ± 0.8 vs. 4.4 ± 1.1, P = 0.177), while Krickenbeck (3.7 ± 1.8 vs. 5.2 ± 1.4) and Rintala (13.7 ± 3.6 vs. 16.0 ± 2.7) scores in Group 1 were significantly lower than those in Group 2 (both P < 0.05). The overall incidence of constipation was 50% (31/62), being higher for Group 1 than Group 2 (77.5% vs. 38.6%, P = 0.002). The area under the curve of ganglia absence for predicting constipation was 0.696, with 77.8% sensitivity and 61.4% specificity.

Conclusion

Ganglia absence in the terminal rectum/fistula of male imperforate anus with RB/RP fistulas is associated with constipation after anoplasty, but it has limited predictive value for postoperative constipation. It is necessary to search for ganglia in the terminal rectum/fistula, both intraoperatively and postoperatively.

Obstructed defecation syndrome: a diagnostic and therapeutic challenge

Obstructed defecation syndrome produces constipation with anal blockage and a feeling of incomplete evacuation, due to either anatomic and functional causes. This is a complex and multifactorial entity due to diverse etiological factors that may coexist in many patients. Therefore, a diagnostic approach requires structural and functional assessment. The concordance between findings of diagnostic tests is suboptimal, thus an individualized analysis is mandatory in each patient. Therapeutic strategies require the best understanding of anatomic and functional aspects. Consequently, this entity is a diagnostic and therapeutic challenge.