No standard diagnostic method or surgical treatment for congenital isolated hypoganglionosis (CIHG) has been established. This study aimed to analyze the clinical outcomes of patients with CIHG and identify the best surgical interventions provided thus far. Data on surgical interventions in 19 patients were collected between 1992 and 2020, including the type of enterostomy, type of revision, and length of the intestines. Ganglion cells in the myenteric plexus were enumerated using Hu C/D staining. The ratio of the length of the small intestine to its height was defined as the intestinal ratio (IR). The outcomes were assessed using the stoma output, growth parameters including the body mass index (BMI), and parenteral nutrition (PN) dependency. All patients required a diverting enterostomy. The IR ranged from 0.51 to 1.75 after multiple non-transplant surgeries. The stoma types were tube-stoma, end-stoma, Santulli-type, and Bishop-Koop (BK)-type. Patients with Santulli- or BK-type stomas had better BMIs and less PN dependency in terms of volume than those with end-stomas or tube-stomas. Two patients with BK-type stomas were off PN, and three who underwent an intestinal transplantation (Itx) achieved enteral autonomy. The management of CIHG involves a precise diagnosis using Hu C/D staining, neonatal enterostomy, and stoma revision using the adjusted IR and Itx if other treatments do not enable enteral autonomy.

Hirschsprung disease (HSCR) and its associated disorders (AD-HSCR) often result in severe hypoperistalsis caused by enteric neuropathy, mesenchymopathy, and myopathy. Notably, HSCR involving the small intestine, isolated hypoganglionosis, chronic idiopathic intestinal pseudo-obstruction, and megacystis-microcolon-intestinal hypoperistalsis syndrome carry a poor prognosis. Ultimately, small-bowel transplantation (SBTx) is necessary for refractory cases, but it is highly invasive and outcomes are less than optimal, despite advances in surgical techniques and management. Thus, regenerative therapy has come to light as a potential form of treatment involving regeneration of the enteric nervous system, mesenchyme, and smooth muscle in affected areas. We review the cutting-edge regenerative therapeutic approaches for managing HSCR and AD-HSCR, including the use of enteric nervous system progenitor cells, embryonic stem cells, induced pluripotent stem cells, and mesenchymal stem cells as cell sources, the recipient intestine\'s microenvironment, and transplantation methods. Perspectives on the future of these treatments are also discussed.

UNASSIGNED: Hypoganglionosis resembles Hirschsprung\'s disease as in both diseases, patients may present with severe constipation or pseudo-obstruction. To date, diagnosis of hypoganglionosis is still difficult to be established due to lack of international consensus regarding diagnostic criteria. This study aims to evaluate the use of immunohistochemistry to provide objective support for our initial subjective impression of hypoganglionosis as well as to describe the morphological features of this study.
UNASSIGNED: This is a cross-sectional study. Three resected intestinal samples from patients with hypoganglionosis at Kyushu University Hospital, Fukuoka, Japan were included in this study. One healthy intestinal sample was used as control. All specimens were immunohistochemically stained with anti-S-100 protein, anti-α-smooth muscle actin (α-SMA), and anti-c-kit protein antibodies.
UNASSIGNED: (I) S-100 immunostaining: hypoplasia of the myenteric ganglia and marked reduction of intramuscular nerve fibers were observed in several segments of the intestine. (II) α-SMA immunostaining: the pattern of the muscular layers was almost normal in all segments; however, some areas showed hypotrophy of the circular muscle (CM) layers and hypertrophy of the longitudinal muscle (LM) layers. (III) C-kit immunostaining: a decreased in the number of interstitial cells of Cajal (ICCs) was observed in almost all segments of the resected intestine, even around the myenteric plexus.
UNASSIGNED: Each segment of intestine in hypoganglionosis had different numbers of ICCs, sizes, and distributions of ganglions, as well as patterns of musculature, which may range from severely abnormal to nearly normal. Further investigations regarding the definition, etiology, diagnosis, and treatment of this disease should be performed to improve the prognosis of this disease.

In this prospective cohort study, we evaluated features of \"adult-onset megacolon with focal hypoganglionosis.\"
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.
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].
Adult-onset megacolon with focal hypoganglionosis has distinct features characterized by hypoganglionosis due to inflammation. Bowel resection appears to benefit these patients.

Introduction and importance: Colonic pseudo-obstruction (CPO) is characterized by massive colonic dilatation of the large intestine without mechanical obstruction. In this study, we report our surgical experience in treating refractory CPO with increased anal sphincter tone, suggested as type IV dyssynergia.
METHODS: A 48-year-old man with intellectual disability, depression, heart failure, and end-stage renal disease presented with acute exacerbation of CPO. He had a history of chronic constipation and abdominal distension. Colonic dilatation and defecation difficulty persisted despite medication and repeated colonoscopic decompression. Anal manometry results indicated type IV dyssynergia with increased rectal pressure. Hartmann\'s operation was performed to resect the redundant megacolon and to avoid increased anal sphincter pressure during defecation. Hypoganglionosis was observed in the resected colon, which could worsen the chronic process of CPO.
UNASSIGNED: Meticulous evaluation and careful management are required to treat CPO patients because the pathophysiology of CPO has not yet been clearly identified. Proper surgical treatment is needed for patients with refractory CPO.
CONCLUSIONS: CPO requires meticulous evaluation and careful management owing to the risk of bowel perforation. Precise evaluation to identify other factors affecting defecation problems accompanied by CPO is required to make appropriate treatment decisions.

Sigmoid volvulus is an extremely rare cause of intestinal obstruction in pediatric patients. This condition occurs when a redundant sigmoid loop with a narrow mesenteric base of attachment to the posterior abdominal wall rotates around its mesenteric axis. This situation might result in vascular occlusion and large bowel obstruction. There are only a few predisposing factors of sigmoid volvulus, such as a long-term history of constipation or pseudo-obstruction with an excessive sigmoid colon. Underlying hypoganglionosis can also lead to large bowel obstruction. There have only been two reported cases of hypoganglionosis with sigmoid volvulus, and both were in adults. Sigmoid volvulus usually presents with abdominal pain, nausea, vomiting, constipation and abdominal distension, an absence of stool, or the presence of melenic stool in the rectum. Initial treatment options are non-surgical for stable patients, although surgical management might be necessary. If sigmoid volvulus is not recognized and resolved, it may lead to serious complications and death. Pediatric sigmoid volvulus is frequently the fulminant type, and therefore, a decision about treatment must be prompt. We present an unusual pediatric case of an extremely long sigmoid colon with hypoganglionosis, which twisted and caused obstruction. This condition was resolved with surgical resection.

Intestinal hypoganglionosis is a rare condition in adults. We report a case of intestinal hypoganglionosis in the mid-distal transverse colon to splenic flexure in a 65-year-old female patient presenting with altered bowel habit and abdominal distension, and reviewed the current literature on this topic. Our patient had a medical history of neurofibromatosis type 1. A preoperative computed tomography (CT) scan demonstrated a grossly dilated transverse colon without obstruction. A laparotomy for subtotal colectomy was performed, with histopathology demonstrating intestinal hypoganglionosis.

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.
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.
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.
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.

BACKGROUND: Retained transition zone is a leading cause of obstructive symptoms after pull-through operation in Hirschsprung\'s disease.
OBJECTIVE: We aimed to evaluate the extent of the histological transition zone in patients with Hirschsprung\'s disease.
METHODS: We performed an observational study. DAB+ immunohistochemistry for Protein Gene Product 9.5 was used to evaluate the neuronal networks in serial sections of pull-through specimens obtained from children with Hirschsprung\'s disease (n = 12). Reference ranges for ganglion size/density and nerve trunk diameter were statistically determined using healthy controls obtained from colostomy specimens from children with anorectal malformations (n = 8). The transition zone was defined as ganglionic bowel exhibiting ganglion hypoplasia, hypertrophic nerve trunks, or partial circumference aganglionosis.
RESULTS: The mean submucosal nerve trunk diameter in controls was 19.56 μm +/- 3.87 μm. The median age at pull-through for Hirschsprung\'s disease was 5 months (3-14 months). The median length of the transition zone across the population was 8 cm (4-22 cm). Median transition zone extent was significantly longer in patients with long-segment aganglionosis (n = 6) compared to rectosigmoid aganglionosis (n = 6, 13 cm vs 6 cm, p = 0.041). Due to the age of the patients enrolled, long-term follow-up of bowel function is not yet available.
CONCLUSIONS: Our data suggest that, in children with rectosigmoid Hirschsprung\'s disease, the transition zone can extend for up to 13 cm. In children with long-segment disease, a longer transition zone is possible. Extended resection at a minimum 5 cm beyond the most distal ganglionic intra-operative biopsy and intra-operative histological examination of the proximal resection margin are required to minimize transition zone pull-through.
METHODS: 2.

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.