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Background: In this prospective cohort study, we evaluated features of "adult‐onset megacolon with focal hypoganglionosis." Methods: We assessed the radiologic, endoscopic, and histopathologic phenotyping and treatment outcomes of 29 patients between 2017 and 2020. Data from community controls, consisting of 19,948 adults undergoing health screenings, were analyzed to identify risk factors. Experts reviewed clinical features and pathological specimens according to the London Classification for gastrointestinal neuromuscular pathology. Key results: The median age of the patients with adult‐onset megacolon with focal hypoganglionosis at symptom onset was 59 years (range, 32.0–74.9 years), with mean symptom onset only 1 year before diagnosis. All patients had focal stenotic regions with proximal bowel dilatation (mean diameter, 78.8 mm; 95% confidence interval [CI], 72–86). The comparison with community controls showed no obvious risk factors. Ten patients underwent surgery, and all exhibited significant hypoganglionosis: 5.4 myenteric ganglion cells/cm (interquartile range [IQR], 3.7–16.4) in the stenotic regions compared to 278 cells/cm (IQR, 190–338) in the proximal and 95 cells/cm (IQR, 45–213) in the distal colon. Hypoganglionosis was associated with CD3+ T cells along the myenteric plexus. Colectomy was associated with significant symptom improvement compared to medical treatment [change in the Global Bowel Satisfaction score, −5.4 points (surgery) vs. ‐0.3 points (medical treatment); p < 0.001]. Conclusions and inferences: Adult‐onset megacolon with focal hypoganglionosis has distinct features characterized by hypoganglionosis due to inflammation. Bowel resection appears to benefit these patients. [ABSTRACT FROM AUTHOR]

Background: Enteric nervous system (ENS) abnormalities have been implicated in delayed gastric emptying but studies exploring potential treatment options are limited by the lack of an experimental animal model. We examined the ENS abnormalities in the mouse stomach associated with aging, developed a novel model of gastroparesis, and established a new approach to measure gastric emptying. Methods: A modified gastric emptying assay was developed, validated in nNOS −/− mice, and tested in mice at multiple ages. Age‐related changes in ENS structure were analyzed by immunohistochemistry. Gastric aganglionosis was generated in Wnt1‐iDTR mice using focal administration of diphtheria toxin (DT) into the anterior antral wall. Key Results: Older mice (>5 months) exhibit hypoganglionosis in the gastric antrum and a decreased proportion of nNOS neurons as compared to younger mice (age 5‐7 weeks). This was associated with a significant age‐dependent decrease in liquid and solid gastric emptying. A novel model of gastric antrum hypoganglionosis was established using neural crest‐specific expression of diphtheria toxin receptor. In this model, a significant reduction in liquid and solid gastric emptying is observed. Conclusions & Inferences: Older mice exhibit delayed gastric emptying associated with hypoganglionosis and a reduction in nNOS‐expressing neurons in the antrum. The causal relationship between antral hypoganglionosis and delayed gastric emptying was verified using a novel experimental model of ENS ablation. This study provides new information regarding the pathogenesis of delayed gastric emptying and provides a robust model system to study this disease and develop novel treatments. [ABSTRACT FROM AUTHOR]

Retinoic acid receptor beta (RARB) variants are heavily linked to pathologies of neural crest cell migration. The purpose of this report is to present a 23‐month‐old male with the previously described R387C RARB gain‐of‐function variant whose gastrointestinal issues and long‐term constipation lead to the discovery of colonic hypoganglionosis. This case further delineates the pattern of malformation associated with RARB variants. The findings are also consistent with the known etiology of aganglionic colon due to failed neural crest cell migration. [ABSTRACT FROM AUTHOR]

In this report, we present the case of a female infant with peripheral demyelinating neuropathy, central dysmyelinating leukodystrophy, Waardenburg syndrome, and Hirschsprung disease (PCWH) associated with a novel frameshift mutation (c.842dupT) in exon 5, the last exon of SOX10. She had severe hypoganglionosis in the small intestine and entire colon, and suffered from frequent enterocolitis. The persistence of ganglion cells made both the diagnosis and treatment difficult in the neonatal period. She also showed hypopigmentation of the irises, hair and skin, bilateral sensorineural deafness with hypoplastic inner year, severe demyelinating neuropathy with hypotonia, and diffuse brain hypomyelination. The p.Ser282GlnfsTer12 mutation presumably escapes from nonsense‐mediated decay and may generate a dominant‐negative effect. We suggest that hypoganglionosis can be a variant intestinal manifestation associated with PCWH and that hypoganglionosis and aganglionosis may share the same pathoetiological mechanism mediated by SOX10 mutations. [ABSTRACT FROM AUTHOR]

This section provides abstracts of poster sessions presented at the 21st International Symposium on Neurogastroenterology and Motility held in Jeju, South Korea in September 2007, including sessions on the sensitivity of guinea-pig small intestinal spinal afferents, telemetric recording of electrogastrogram, and changes in serum gastrin levels.

A 14-yr-old boy with total parenteral nutrition-dependent short-bowel syndrome associated with hypoganglionosis underwent the LR-IT by using a 150 cm segment of distal ileum taken from a healthy donor. The graft vessels were connected to infrarenal aorta and inferior vena cava. The immunosuppressive regimen consisted of daclizumab, tacrolimus, and steroid. The graft surveillance for ACR was accomplished using zoom endoscopy and mucosal biopsy. The blood trough level of tacrolimus was maintained between 20 and 25 ng/mL for the first 2 months, followed by 15–20 ng/mL thereafter. The 50 mg of daclizumab was administered on the day of operation, and same dosage was repeated at 2-wk intervals. The first ACR occurred on POD-9 and was progressive, and required a 14-day course of OKT-3 injection. After the treatment with OKT-3, the graft recovered from the ACR, and began to function well enough to discontinue the intravenous nutrition on POD-55. No infectious complication has occurred. The patient was discharged in POD-112, and currently tolerates full oral intake without requiring intravenous nutritional or fluid supplementation. The donor was discharged without any complications. The LR-IT could successfully be performed with minimal risk to the donor, and it can be a treatment of choice for patients with short-gut syndrome associated with hypoganglionosis. [ABSTRACT FROM AUTHOR]

In this report, we present the case of a female infant with peripheral demyelinating neuropathy, central dysmyelinating leukodystrophy, Waardenburg syndrome, and Hirschsprung disease (PCWH) associated with a novel frameshift mutation (c.842dupT) in exon 5, the last exon of SOX10. She had severe hypoganglionosis in the small intestine and entire colon, and suffered from frequent enterocolitis. The persistence of ganglion cells made both the diagnosis and treatment difficult in the neonatal period. She also showed hypopigmentation of the irises, hair and skin, bilateral sensorineural deafness with hypoplastic inner year, severe demyelinating neuropathy with hypotonia, and diffuse brain hypomyelination. The p.Ser282GlnfsTer12 mutation presumably escapes from nonsense-mediated decay and may generate a dominant-negative effect. We suggest that hypoganglionosis can be a variant intestinal manifestation associated with PCWH and that hypoganglionosis and aganglionosis may share the same pathoetiological mechanism mediated by SOX10 mutations., (© 2018 Wiley Periodicals, Inc.)