Development of the aganglionic colon following surgical rescue in a cell therapy model of Hirschsprung disease in rat

Patients with Hirschsprung Disease lack enteric ganglia in the distal colon and propulsion of colorectal content is substantially impaired. Proposed stem cell therapies to replace neurons require surgical bypass of the aganglionic bowel during re-colonisation, but there is inadequate knowledge of the consequences of bypass. We performed bypass surgery in Ednrb-/- Hirschsprung rat pups. Surgically rescued rats failed to thrive, an outcome reversed by supplying electrolyte and glucose enriched drinking water. Histologically, the bypassed colon had normal structure, but grew substantially less in diameter than the functional region proximal to the bypass. Extrinsic sympathetic and spinal afferent neurons projected to their normal targets, including arteries and the circular muscle, in aganglionic regions. However, although axons of intrinsic excitatory and inhibitory neurons grew into the aganglionic region, their normally dense innervation of circular muscle was not restored. Large nerve trunks that contained TH, CGRP, nNOS, VIP and tachykinin immunoreactive axons occurred in the distal aganglionic region. We conclude that the rescued Ednrb-/- rat provides a good model for the development of cell therapies for the treatment of Hirschsprung disease.

A Single RET Mutation in Hirschsprung Disease Induces Intestinal Aganglionosis Via a Dominant-Negative Mechanism

BACKGROUND & AIMS

Hirschsprung disease (HSCR) is a congenital disorder characterized by the absence of the enteric nervous system (ENS). HSCR potentially involves multiple gene aberrations and displays complex patterns of inheritance. Mutations of the RET gene, encoding the RET receptor tyrosine kinase, play a central role in the pathogenesis of HSCR. Although a wide variety of coding RET mutations have been identified, their pathogenetic significance in vivo has remained largely unclear.

METHODS

We introduced a HSCR-associated RET missense mutation, RET(S811F), into the corresponding region (S812) of the mouse Ret gene. Pathogenetic impact of Ret(S812F) was assessed by histologic and functional analyses of the ENS and by biochemical analyses. Interactions of the Ret(S812F) allele with HSCR susceptibility genes, the RET9 allele and the Ednrb gene, were examined by genetic crossing in mice.

RESULTS

Ret^S812F/+ mice displayed intestinal aganglionosis (incidence, 50%) or hypoganglionosis (50%), impaired differentiation of enteric neurons, defecation deficits, and increased lethality. Biochemical analyses revealed that Ret(S811F) protein was not only kinase-deficient but also abrogated function of wild-type RET in trans. Moreover, the Ret(S812F) allele interacted with other HSCR susceptibility genes and caused intestinal aganglionosis with full penetrance.

CONCLUSIONS

This study demonstrates that a single RET missense mutation alone induces intestinal aganglionosis via a dominant-negative mechanism. The Ret^S812F/+ mice model HSCR displays dominant inheritance with incomplete penetrance and serves as a valuable platform for better understanding of the pathogenetic mechanism of HSCR caused by coding RET mutations.

Congenital anomalies of the tubular gastrointestinal tract

Congenital anomalies of the tubular gastrointestinal tract are an important cause of morbidity not only in infants, but also in children and adults. The gastrointestinal (GI) tract, composed of all three primitive germ layers, develops early during embryogenesis. Two major steps in its development are the formation of the gut tube (giving rise to the foregut, the midgut and the hindgut), and the formation of individual organs with specialized cell types. Formation of an intact and functioning GI tract is under strict control from various molecular pathways. Disruption of any of these crucial mechanisms involved in the cell-fate decision along the dorsoventral, anteroposterior, left-right and radial axes, can lead to numerous congenital anomalies, most of which occur and present in infancy. However, they may run undetected during childhood. Therapy is surgical, which in some cases must be performed urgently, and prognosis depends on early diagnosis and suitable treatment. A precise pathologic macroscopic or microscopic diagnosis is important, not only for the immediate treatment and management of affected individuals, but also for future counselling of the affected individual and their family. This is even more true in cases of multiple anomalies or syndromic patterns. We discuss some of the more frequent or clinically important congenital anomalies of the tubular GI, including atresia's, duplications, intestinal malrotation, Meckel's diverticulum and Hirschsprung's Disease.

Prevalence of Hirschsprung-associated enterocolitis in patients with Hirschsprung disease

PURPOSE

Hirschsprung's associated enterocolitis (HAEC) is a complication of Hirschsprung's Disease (HD) with considerable morbidity and mortality. The variability in presentation leads to a wide variety of the reported prevalence pre-and postoperatively. This systematic review aimed to clarify the prevalence of HAEC in short-(S-HD), long (L-HD), TCA and the type of operation used.

METHODS

A systematic literature-based search for relevant cohorts was performed using Pubmed/Medline, Cochrane Library from its inception to May 2021. Studies reporting on pre-and postoperative enterocolitis, segment length, and surgical procedure (Soave, Swenson, Duhamel) were included. Pooled prevalence and subgroup analysis have been calculated for pre-and postoperative HAEC.

RESULTS

4738 articles were identified from the literature search, among which 57 studies, including 9744 preoperative and 8568 postoperative patients, were included. The groups were sorted by length of the aganglionic segment for further analysis. The pooled prevalence for preoperative HAEC was 18.3% for all types, 15.2% for S-HD and 26.1% for TCA. The pooled prevalence for postoperative HAEC was in total 18.2% for all segment lengths and used techniques. Subgroup analysis showed no significant difference in the occurrence of postoperative enterocolitis between the three techniques.

CONCLUSION

The prevalence of preoperative HAEC increases with segment length. However, pooled data suggest that the postoperative risk for developing HAEC, independently of the employed method and segment length, is comparable to the preoperative risk.

Outpatient Botulinum Injections for Early Obstructive Symptoms in Patients with Hirschsprung Disease

INTRODUCTION

Botulinum toxin (BT) injections may play a role in preventing Hirschsprung associated enterocolitis (HAEC) episodes related to internal anal sphincter (IAS dysfunction). Our aim was to determine the association of outpatient BT injections for early obstructive symptoms on the development of HAEC.

METHODS

A retrospective review of children who underwent definitive surgery for Hirschsprung disease (HSCR) from July 2010 - July 2020 was performed. The timing from pull-through to first HAEC episode and to first BT injection was recorded. Primary analysis focused on the rate of HAEC episodes and timing between episodes in patients who did and did not receive BT injections.

RESULTS

Eighty patients were included. Sixty patients (75%) were male, 15 (19%) were diagnosed with trisomy 21, and 58 (72.5%) had short-segment disease. The median time to pull-through was 150 days (IQR 16, 132). Eight patients (10%) had neither an episode of HAEC or BT injections and were not included in further analysis. Forty-six patients (64%) experienced at least one episode of HAEC, while 64 patients (89%) had at least one outpatient BT injection. Compared to patients who never received BT injections (n = 9) and those who developed HAEC prior to BT injections (n = 35), significantly fewer patients who received BT injections first (n = 28) developed enterocolitis (P < 0.001), with no patient developing more than one HAEC episode.

CONCLUSION

Outpatient BT is associated with decreased episodes of HAEC and increased interval between HAEC episodes requiring inpatient treatment. Scheduling outpatient BT injections to manage obstructive symptoms may be beneficial after pull-through for HSCR.

Robust, 3-Dimensional Visualization of Human Colon Enteric Nervous System Without Tissue Sectioning

BACKGROUND & AIMS

Small, 2-dimensional sections routinely used for human pathology analysis provide limited information about bowel innervation. We developed a technique to image human enteric nervous system (ENS) and other intramural cells in 3 dimensions.

METHODS

Using mouse and human colon tissues, we developed a method that combines tissue clearing, immunohistochemistry, confocal microscopy, and quantitative analysis of full-thickness bowel without sectioning to quantify ENS and other intramural cells in 3 dimensions.

RESULTS

We provided 280 adult human colon confocal Z-stacks from persons without known bowel motility disorders. Most of our images were of myenteric ganglia, captured using a 20× objective lens. Full-thickness colon images, viewed with a 10× objective lens, were as large as 4 × 5 mm². Colon from 2 pediatric patients with Hirschsprung disease was used to show distal colon without enteric ganglia, as well as a transition zone and proximal pull-through resection margin where ENS was present. After testing a panel of antibodies with our method, we identified 16 antibodies that bind to molecules in neurons, glia, interstitial cells of Cajal, and muscularis macrophages. Quantitative analyses demonstrated myenteric plexus in 24.5% ± 2.4% of flattened colon Z-stack area. Myenteric ganglia occupied 34% ± 4% of myenteric plexus. Single myenteric ganglion volume averaged 3,527,678 ± 573,832 mm³ with 38,706 ± 5763 neuron/mm³ and 129,321 ± 25,356 glia/mm³. Images of large areas provided insight into why published values of ENS density vary up to 150-fold-ENS density varies greatly, across millimeters, so analyses of small numbers of thin sections from the same bowel region can produce varying results. Neuron subtype analysis revealed that approximately 56% of myenteric neurons stained with neuronal nitric oxide synthase antibody and approximately 33% of neurons produce and store acetylcholine. Transition zone regions from colon tissues of patients with Hirschsprung disease had ganglia in multiple layers and thick nerve fiber bundles without neurons. Submucosal neuron distribution varied among imaged colon regions.

CONCLUSIONS

We developed a 3-dimensional imaging method for colon that provides more information about ENS structure than tissue sectioning. This approach could improve diagnosis for human bowel motility disorders and may be useful for other bowel diseases as well.

Activation of Hedgehog Signaling Promotes Development of Mouse and Human Enteric Neural Crest Cells, Based on Single-Cell Transcriptome Analyses

BACKGROUND & AIMS

It has been a challenge to develop fully functioning cells from human pluripotent stem cells (hPSCs). We investigated how activation of hedgehog signaling regulates derivation of enteric neural crest (NC) cells from hPSCs.

METHODS

We analyzed transcriptomes of mouse and hPSC-derived enteric NCs using single-cell RNA sequencing (scRNA-seq) to identify the changes in expression associated with lineage differentiation. Intestine tissues were collected from Tg(GBS-GFP), Sufu^{f/f; Wnt1-cre}, Ptch1^+/-, and Gli3^Δ699/Δ699 mice and analyzed by flow cytometry and immunofluorescence for levels of messenger RNAs encoding factors in the hedgehog signaling pathway during differentiation of enteric NCs. Human NC cells (HNK-1⁺p75^NTR+) were derived from IMR90 and UE02302 hPSC lines. hPSCs were incubated with a hedgehog agonist (smoothened agonist [SAG]) and antagonists (cyclopamine) and analyzed for differentiation. hPSC-based innervated colonic organoids were derived from these hPSC lines and analyzed by immunofluorescence and neuromuscular coupling assay for expression of neuronal subtype markers and assessment of the functional maturity of the hPSC-derived neurons, respectively.

RESULTS

Single-cell RNA sequencing analysis showed that neural fate acquisition by human and mouse enteric NC cells requires reduced expression of NC- and cell cycle-specific genes and up-regulation of neuronal or glial lineage-specific genes. Activation of the hedgehog pathway was associated with progression of mouse enteric NCs to the more mature state along the neuronal and glial lineage differentiation trajectories. Activation of the hedgehog pathway promoted development of cultured hPSCs into NCs of greater neurogenic potential by activating expression of genes in the neurogenic lineage. The hedgehog agonist increased differentiation of hPSCs into cells of the neuronal lineage by up-regulating expression of GLI2 target genes, including INSM1, NHLH1, and various bHLH family members. The hedgehog agonist increased expression of late neuronal markers and neuronal activities in hPSC-derived neurons.

CONCLUSIONS

In enteric NCs from humans and mice, activation of hedgehog signaling promotes differentiation into neurons by promoting cell-state transition, expression of genes in the neurogenic lineage, and functional maturity of enteric neurons.

A descriptive model for a multidisciplinary unit for colorectal and pelvic malformations

INTRODUCTION

Patients with anorectal malformations (ARM), Hirschsprung disease (HD), and colonic motility disorders often require care from specialists across a variety of fields, including colorectal surgery, urology, gynecology, and GI motility. We sought to describe the process of creating a collaborative process for the care of these complex patients.

METHODS

We developed a model of a devoted center for these conditions that includes physicians, psychologists, social workers, nurses, and advanced practice nurses. Our weekly planning strategy includes a meeting with representatives of all specialties to review all patients prior to evaluation in our multidisciplinary clinic, followed by combined exams under anesthesia or surgical intervention as needed.

RESULTS

There are 31 people working directly in the Center at present. From the Center's start in 2014 until 2017, 1258 patients were cared for from all 50 United States and 62 countries. 360 patients had an ARM (110 had a cloacal malformation, 11 had cloacal exstrophy), 223 presented with HD, 71 had a spinal malformation or injury causing neurogenic bowel, 321 had severe functional constipation or colonic dysmotility, and 162 had other diagnoses including familial polyposis, Crohn's disease, or ulcerative colitis. We have had 170 multidisciplinary meetings, 170 multispecialty outpatient, and 52 nurse practitioner clinics. In our bowel management program we have seen a total of 514 patients in 36 sessions.

CONCLUSION

This is the first report describing the design of a multidisciplinary team approach for patients with colorectal and complex pelvic malformations. We found that approaching these patients in a collaborative way allows for combined medical and surgical decisions with many providers simultaneously, facilitates therapy, and can potentially improve patient outcomes. We hope that this model will help establish new-devoted centers in other locations to encourage centralized care for these rare malformations.

LEVEL OF EVIDENCE

IV.

Enteric Neural Cells From Hirschsprung Disease Patients Form Ganglia in Autologous Aneuronal Colon

BACKGROUND & AIMS

Hirschsprung disease (HSCR) is caused by failure of cells derived from the neural crest (NC) to colonize the distal bowel in early embryogenesis, resulting in absence of the enteric nervous system (ENS) and failure of intestinal transit postnatally. Treatment is by distal bowel resection, but neural cell replacement may be an alternative. We tested whether aneuronal (aganglionic) colon tissue from patients may be colonized by autologous ENS-derived cells.

METHODS

Cells were obtained and cryopreserved from 31 HSCR patients from the proximal resection margin of colon, and ENS cells were isolated using flow cytometry for the NC marker p75 (nine patients). Aneuronal colon tissue was obtained from the distal resection margin (23 patients). ENS cells were assessed for NC markers immunohistologically and by quantitative reverse-transcription polymerase chain reaction, and mitosis was detected by ethynyl-2'-deoxyuridine labeling. The ability of human HSCR postnatal ENS-derived cells to colonize the embryonic intestine was demonstrated by organ coculture with avian embryo gut, and the ability of human postnatal HSCR aneuronal colon muscle to support ENS formation was tested by organ coculture with embryonic mouse ENS cells. Finally, the ability of HSCR patient ENS cells to colonize autologous aneuronal colon muscle tissue was assessed.

RESULTS

ENS-derived p75-sorted cells from patients expressed multiple NC progenitor and differentiation markers and proliferated in culture under conditions simulating Wnt signaling. In organ culture, patient ENS cells migrated appropriately in aneural quail embryo gut, and mouse embryo ENS cells rapidly spread, differentiated, and extended axons in patient aneuronal colon muscle tissue. Postnatal ENS cells derived from HSCR patients colonized autologous aneuronal colon tissue in cocultures, proliferating and differentiating as neurons and glia.

CONCLUSIONS

NC-lineage cells can be obtained from HSCR patient colon and can form ENS-like structures in aneuronal colonic muscle from the same patient.

Diagnostic accuracy of radiologic scoring system for evaluation of suspicious hirschsprung disease in children

BACKGROUND

In 1996, Donovan and colleagues represented a scoring system for better prediction of Hirschsprung disease (HD).

OBJECTIVES

Our objective was to devise another scoring system that uses a checklist of radiologic and clinical signs to determine the probability of HD in suspicious patients.

PATIENTS AND METHODS

In a diagnostic accuracy study, 55 children with clinical manifestations of HD that referred to a training hospital from 1998 to 2011 were assessed. A checklist was used to evaluate the items proposed by contrast enema (CE), based on six subscales, including transitional zone, rectosigmoid index (RSI), irregular contractions in aganglionic region, cobblestone appearance, filling defect due to fecaloid materials and lack of meconium defecation during the first 48 hours after birth. The patients were classified as high score and low score. Sensitivity, specificity, positive predictive value and negative predictive value of our scoring system were calculated for identifying HD, in comparison with pathologically proved or ruled out HD.

RESULTS

Of the 55 patients, 36 (65.4%) cases had HD and 19 (34.6%) cases were without HD. In the HD group, 32 patients showed high scores and four patients had low scores. The sensitivity and specificity of our diagnostic scoring system were 88.9% (95% CI: 78.6% - 99.1%) and 84.2% (95% CI: 68.7% - 100%), respectively. Moreover, positive predictive value (PPV) and negative predictive value (NPV) were 91.4% (95% CI: 82.1% - 100%) and 80% (95% CI: 62.5% - 97.5%), respectively.

CONCLUSIONS

Our new scoring system of CE is a useful diagnostic method in HD. If a patient's score is high, that patient is highly suspicious to HD and reversely, when one's score is low, the patient presents a reduced probability to be diagnosed with HD.

Evaluation of Calretinin as a New Marker in the Diagnosis of Hirschsprung Disease

Background:

Hirschsprung’s disease (HD) is a congenital intestinal motility disorder with absence of ganglion cells in the colonic wall. Diagnosis of the disease is mainly based on the identification of the lack of ganglion cells in the pathology sections of the colon which is very difficult and time consuming and also needs several serial cut sections. There are many proposed markers in this field in the literature but none of them has been satisfactory. Calretinin immunohistochemistry (IHC) has been introduced as a new diagnostic marker to overcome the problems in diagnosis of this disease about 5 years ago. However there are few studies regarding the benefits and pitfalls of this marker.

Objectives:

The aim of this study is to determine the diagnostic value of calretinin IHC in detecting aganglionosis (HD).

Patients and Methods:

27 HD patients and 28 non-Hirschsprung’s disease (NHD) patients were collected in a prospective study and calretinin IHC was performed on 31 aganglionic and 51 normoganglionic full wall thickness sections of colectomies (some of the cases had more than 1 section). The IHC slides were evaluated by two pathologists and the diagnostic value was calculated in comparison with gold standard which is the presence or absence of ganglion cells in serial Hematoxylin and Eosin (HE) stained sections of the colectomies.

Results:

There was great concordance between the final diagnosis of both pathologists and gold standard (k > 0.9). Calretinin immunostaining showed 100% specificity and positive predictive value and more than 90% sensitivity and negative predictive value. High agreement was present between the two pathologists (k > 0.9).

Conclusions:

Calretinin IHC is a very convenient, useful and valuable method to demonstrate aganglionosis in HD patients. Loss of calretinin immunostaining in lamina propria and submucosa is characteristic of HD.

Transition of care in pediatric surgical patients with complex gastrointestinal disease

Pediatric surgeons provide care for infants and children with a wide variety of conditions throughout the body. Many of these conditions are congenital or occur very early in life, and for this reason, providing continuity of care for these patients into adulthood is an emerging challenge. In the gastrointestinal tract, congenital and acquired conditions are now associated with excellent long-term prognosis; however, little guidance on long-term care exists. The aim of this article is to discuss aspects that are important to transitioning care of pediatric surgical patients with complex gastrointestinal disorders from pediatric to adult practitioners. Transitional care of patients with short bowel syndrome, Hirschsprung Disease, and anorectal malformations will be the focus of this discussion, but the concepts introduced here may translate to other diagnoses as well.

Blepharophimosis, short humeri, developmental delay and hirschsprung disease: expanding the phenotypic spectrum of MED12 mutations

We report on two male sibs, a fetus and a newborn, with short humeri and dysmorphic facial features including blepharophimosis. The newborn also had Hirschsprung disease. Goldberg-Shprintzen syndrome and the Say-Barber-Biesecker-Young-Simpson type of Ohdo syndrome were suspected but direct sequencing of KBP and KAT6B failed to identify a mutation. Finally, direct sequencing of MED12, the gene mutated in Opitz-Kaveggia syndrome, Lujan-Fryns syndrome and X-linked Ohdo syndrome identified in the two sibs the missense mutation c.3443G>A (p.Arg1148His) inherited from the mother. This report further expands the phenotypic spectrum of MED12 mutations.

Hirschsprung's disease: the importance of early diagnosis

Congenital intestinal aganglionosis, also called Hirschsprung disease (HD), is defined as the absence of ganglionic cells in the myenteric (Auerbach) and submucosal (Meissner) plexus, due to a failure in the enteric nervous system development. The extent of intestinal involvement may vary according to the age of embryo development in which this failure occurs. It is not unusual for other malformations to be present, as well as chromosomal trisomies, manly trisomy 21. Enterocolitis is a frequent, life threatening, and feared complication of HD. Moreover, oligohydramnios is a well-known condition frequently associated with malformations, including those related to the gastrointestinal tract. The authors report the case of a newborn that presented a delayed meconium passage. On the third day of life, he presented enterocolitis—the outcome of which was favorable with clinical treatment. While the diagnosis of HD was awaiting confirmation, the enterocolitis relapsed and this time he died due to septic shock. The autopsy findings were compatible with a short segment of congenital intestinal aganglionosis. No other malformation was found. The authors call attention for an early diagnosis of HD whenever the meconium passage does not happen for at least 48 hours and for the risk factors of enterocolitis. This case also demonstrates HD associated with oligohydramnios.

Hirschsprung disease of the colon, a vaginal mass and medullary thyroid cancer - a RET oncogene driven problem

This case report emphasizes the fact that all patients with Hirschsprung disease should be screened for RET Oncogene mutation as there is a well known association between Hirschsprung Disease and Multiple Endocrine Neoplasia (MEN) Type 2A. It also reminds us that Medullary Thyroid Carcinoma is known to cause elevated levels of CEA which does not originate from gastrointestinal tract.

Calretinin Immunohistochemistery: An Aid in the Diagnosis of Hirschsprung's Disease

OBJECTIVES

Definite diagnosis of Hirschsprung's disease (HD) is based on histopathological study, but there are limitations associated with standard histology and histochemistry in this regard. The aim of this study was to investigate calretinin immunostaining patterns in both ganglionic and aganglionic HD intestinal specimens and to compare them with control specimens.

MATERIALS AND METHODS

Specimens included 30 patients with histopathologic diagnosis of HD and 20 patients that underwent colectomy for other reasons (as control group). Eighty paraffin wax blocks of full thickness intestinal specimens (30 blocks of ganglionic segments, 30 blocks of aganglionic segments and 20 blocks of control group) were studied. Calretinin immunoreactivity and pattern of staining for ganglion cells (nuclear and cytoplasmic) and also nerve fibers in different layers of bowel were evaluated in IHC stained slides.

RESULTS

There were positive immunostaining of nerve fibers in the lamina propria, submucosa and muscularis propria in control and patient group. There were also nuclear and cytoplasmic staining of ganglion cells in submucosa and muscularis propria in all specimens of both control group (100%) and ganglionic segments (100%). Calretinin immunoexpression of nerve fibers in muscularis propria of the aganglionic segments was negative in all but two cases (6.7%). This method had sensitivity of 93.3% and specificity of 100% for diagnosis of HD in full thickness specimens of intestinal wall. The positive predictive value was 100% and negative predictive value was 93.8%.

CONCLUSION

Calretinin immunohistochemistry can be used on suction rectal biopsies as a reliable and adjunctive method to diagnose HD.

Haddad syndrome with PHOX2B gene mutation in a Korean infant

Congenital central hypoventilation syndrome with Hirschsprung's disease, also known as Haddad syndrome, is an extremely rare disorder with variable symptoms. Recent studies described that congenital central hypoventilation syndrome had deep relation to the mutation of the PHOX2B gene in its diagnosis and phenotype. We report a newborn male infant with clinical manifestations of recurrent hypoventilation with hypercapnea and bowel obstruction. These clinical manifestations were compatible with congenital central hypoventilation syndrome and Hirschsprung's disease, and polyalanine 26 repeats in the PHOX2B gene supported the diagnosis of congenital central hypoventilation. We described a first case of Haddad syndrome in Korean and its clinical and genetic characteristics were discussed.