Clinical aspects of neurointestinal disease: Pathophysiology, diagnosis, and treatment

Current and future state of the management of Hirschsprung disease

The enteric nervous system (ENS) consists of a network of neurons and glia that control numerous complex functions of the gastrointestinal tract. Hirschsprung disease (HSCR) is a congenital disorder characterized by the absence of ENS along variable lengths of distal intestine due to failure of neural crest-derived cells to colonize the distal intestine during embryonic development. A patient with HSCR usually presents with severe constipation in the neonatal period and is diagnosed by rectal suction biopsy, followed by pull-through procedure to surgically remove the affected segment and reconnect the proximal ganglionated intestine to the anus. Outcomes after pull-through surgery are suboptimal and many patients suffer from ongoing issues of dysmotility and bowel dysfunction, suggesting there is room for optimizing the management of this disease. This review focuses on discussing the recent advances to better understand HSCR and leverage them for more accurate and potentially less invasive diagnosis. We also discuss the potential future management of HSCR, particularly cell-based approaches for the treatment of HSCR.

Hirschsprung's disease may increase the incidence of inflammatory bowel disease through alterations in CA1

BACKGROUND

The role of Hirschsprung's disease (HSCR) for the development of inflammatory bowel disease (IBD) and the common pathogenesis of the diseases remains unclear. The objective is to investigate the relationship between HSCR and IBD.

METHODS

In our study, the Mendelian randomization approach was employed to analyze the causal relationships. A further search was conducted for differentially expressed genes (DEGs) between disease and control tissues in HSCR and IBD. Subsequently, the potential pathway mechanisms were subjected to an enrichment analysis. Furthermore, the molecular docking was employed to investigate the binding relationship between potential therapeutic targets and drugs.

RESULTS

The results show HSCR have an increased risk of developing IBD (IVW: OR = 1.048, P < 0.05; weighted median: OR = 1.065, P < 0.05). A total of 111 DEGs were identified in IBD, while 471 DEGs were observed in HSCR. CA1 was identified as core gene and exhibited lower expression levels in IBD (P < 0.05). Concomitantly, CA1 exhibited reduced expression levels in inflamed tissues. And the TNF and IL17 signaling pathway were found closely related to CA1 expression.

CONCLUSION

In total, our study shows HSCR promote the occurrence of IBD and reveals pathogenesis. Our results suggest CA1 may provide novel insight for the treatment of HSCR complicated with IBD.

IMPACT

Individuals with HSCR are at a higher risk of developing IBD (IVW: OR = 1.048, P < 0.05; Weighted median: OR = 1.065, P < 0.05). Patients with IBD exhibited lower expression levels of CA1 (P < 0.05). Furthermore, CA1 expression was found to be lower in inflamed tissues (P < 0.05). CA1 may provide novel insight for the treatment of HSCR complicated with IBD.

The expanding clinical and genetic spectrum of DYNC1H1-related disorders

Intracellular trafficking involves an intricate machinery of motor complexes, including the dynein complex, to shuttle cargo for autophagolysosomal degradation. Deficiency in dynein axonemal chains, as well as cytoplasmic light and intermediate chains, have been linked with ciliary dyskinesia and skeletal dysplasia. The cytoplasmic dynein 1 heavy chain protein (DYNC1H1) serves as a core complex for retrograde trafficking in neuronal axons. Dominant pathogenic variants in DYNC1H1 have been previously implicated in peripheral neuromuscular disorders (NMD) and neurodevelopmental disorders (NDD). As heavy-chain dynein is ubiquitously expressed, the apparent selectivity of heavy chain dyneinopathy for motor neuronal phenotypes remains currently unaccounted for. Here, we aimed to evaluate the full DYNC1H1-related clinical, molecular and imaging spectrum, including multisystem features and novel phenotypes presenting throughout life. We identified 47 cases from 43 families with pathogenic heterozygous variants in DYNC1H1 (aged 0-59 years) and collected phenotypic data via a comprehensive standardized survey and clinical follow-up appointments. Most patients presented with divergent and previously unrecognized neurological and multisystem features, leading to significant delays in genetic testing and establishing the correct diagnosis. Neurological phenotypes include novel autonomic features, previously rarely described behavioral disorders, movement disorders and periventricular lesions. Sensory neuropathy was identified in nine patients (median age of onset 10.6 years), of which five were only diagnosed after the second decade of life, and three had a progressive age-dependent sensory neuropathy. Novel multisystem features included primary immunodeficiency, bilateral sensorineural hearing loss, organ anomalies and skeletal manifestations, resembling the phenotypic spectrum of other dyneinopathies. We also identified an age-dependent biphasic disease course with developmental regression in the first decade and, following a period of stability, neurodegenerative progression after the second decade of life. Of note, we observed several cases in whom neurodegeneration appeared to be prompted by intercurrent systemic infections with double-stranded DNA viruses (Herpesviridae) or single-stranded RNA viruses (Ross River fever, SARS-CoV-2). Moreover, the disease course appeared to be exacerbated by viral infections regardless of age and/or severity of neurodevelopmental disorder manifestations, indicating a role of dynein in anti-viral immunity and neuronal health. In summary, our findings expand the clinical, imaging and molecular spectrum of pathogenic DYNC1H1 variants beyond motor neuropathy disorders and suggest a life-long continuum and age-related progression due to deficient intracellular trafficking. This study will facilitate early diagnosis and improve counselling and health surveillance of affected patients.

Highly neurogenic glia from human and mouse myenteric ganglia generate functional neurons following culture and transplantation into the gut

Enteric neural stem cell (ENSC) therapy offers great promise for neurointestinal diseases; however, current isolation methods yield insufficient neurons for regenerative applications. Multiomic profiling of enteric glial cells (EGCs) suggests that subpopulations within myenteric ganglia (MyGa) are a reservoir of highly neurogenic ENSCs. Here, we describe protocols to enrich for intraganglionic EGCs by isolating intact fragments of MyGa, generating cultures with higher neuronal purity than traditional methodologies isolating intramuscular single cells (IM-SCs). MyGa-derived EGCs transdifferentiate into more neurons than IM-SC-derived EGCs do, confirming their neurogenic predisposition. Following transplantation to the mouse intestine, MyGa-derived neurons generate calcium transients and activate smooth muscle in response to optogenetic stimulation. In the human intestine, MyGa-derived cells are similarly highly neurogenic, are enriched for a distinct progenitor population identified by single-cell RNA sequencing (scRNA-seq), and exhibit neuromuscular connectivity following xenogeneic transplantation into mice. Highly neurogenic ENSCs are preferentially located within the MyGa, and their selective isolation offers considerable potential for therapy.

Enhancement of enteric neural stem cell neurogenesis by glial cell-derived neurotrophic factor in experimental Hirschsprung's disease

PURPOSE

Stem cell therapy offers a promising solution for congenital diseases like Hirschsprung's disease (HSCR). Optimizing stem cell efficacy by modifying the cells and their environment is crucial, but in vitro culture conditions need to be further improved. Glial cell-derived neurotrophic factor (GDNF) plays an important role in neuronal survival, proliferation, migration and differentiation during enteric nervous system (ENS) development. In this study, the effects of GDNF on neurites derived from an Ednrb knockout model were investigated with the aim of enhancing the neurogenic potential of enteric neural crest cells (ENCCs).

METHODS

Neurospheres were generated form Ednrb+/+ (control) and Ednrb-/- mice at embryonic day13.5 (E13.5) with Sox10-green fluorescent protein (Venus) transgenic expression. These neurospheres were cultured in control media and neurospheres from Ednrb-/- were cultured with either control media or media supplemented with GDNF. ENCCs differentiation was assessed using immunofluorescence staining after 18 days.

RESULTS

GDNF-treated Ednrb-/- neurospheres showed increased size and higher density of Sox10-positive ENCCs compared to untreated Ednrb-/- neurospheres. GDNF also enhanced the distribution of both TUJ1-positive neurons and S100-positive glial cells.

CONCLUSION

GDNF effectively enhanced the neurogenic potential of ENCCs from HSCR animal model. This finding is crucial for the development of cell therapy in HSCR.

Mature enteric neurons have the capacity to reinnervate the intestine with glial cells as their guide

Here, we establish that plasticity exists within the postnatal enteric nervous system by demonstrating the reinnervation potential of post-mitotic enteric neurons (ENs). Employing BAF53b-Cre mice for selective neuronal tracing, the reinnervation capabilities of mature postnatal ENs are shown across multiple model systems. Isolated ENs regenerate neurites in vitro, with neurite complexity and direction influenced by contact with enteric glial cells (EGCs). Nerve fibers from transplanted ENs exclusively interface and travel along EGCs within the muscularis propria. Resident EGCs persist after Cre-dependent ablation of ENs and govern the architecture of the myenteric plexus for reinnervating ENs, as shown by nerve fiber projection tracing. Transplantation and optogenetic experiments in vivo highlight the rapid reinnervation potential of post-mitotic neurons, leading to restored gut muscle contractile activity within 2 weeks. These studies illustrate the structural and functional reinnervation capacity of post-mitotic ENs and the critical role of EGCs in guiding and patterning their trajectories.

The 5HT4R agonist velusetrag efficacy on neuropathic chronic intestinal pseudo-obstruction in PrP-SCA7-92Q transgenic mice

Background

Chronic intestinal pseudo-obstruction (CIPO) is a type of intestinal dysfunction with symptoms of intestinal blockage but without the actual mechanical obstruction. Currently, there are no drugs available to treat this disease. Herein, we report the characterization of the PrP-SCA7-92Q transgenic (Tg) line as a valuable CIPO mouse model and investigated the tolerability and efficacy of the 5-hydroxytryptamine type-4 receptor (5HT4R) agonist velusetrag as a promising pharmacological treatment for CIPO.

Methods

To test the pharmacodynamics of velusetrag, 8-week-old SCA7 Tg mice, which express human mutated Ataxin-7 gene containing 92 CAG repeats under the mouse prion protein promoter, were treated for 5 weeks by oral route with velusetrag at 1 and 3 mg/kg doses or vehicle. Body weight was monitored throughout the treatment. After sacrifice, the small intestine and proximal colon were collected for whole-mount immunostaining. Untreated, age-matched, C57BL/6J mice were also used as controls in comparison with the other experimental groups.

Results

Analysis of SCA7 Tg mice showed tissue damage and alterations, mucosal abnormalities, and ulcers in the distal small intestine and proximal colon. Morphological changes were associated with significant neuronal loss, as shown by decreased staining of pan-neuronal markers, and with accumulation of ataxin-7-positive inclusions in cholinergic neurons. Administration of velusetrag reversed intestinal abnormalities, by normalizing tissue damage and re-establishing the normal level of glia/neuron's count in both the small and large intestines.

Conclusion

We demonstrated that the PrP-SCA7-92Q Tg line, a model originally developed to mimic spinocerebellar ataxia, is suitable to study CIPO pathology and can be useful in establishing new therapeutic strategies, such as in the case of velusetrag. Our results suggest that velusetrag is a promising compound to treat patients affected by CIPO or intestinal dysmotility disease.

Sacral neuromodulation in children and adolescents with defecation disorders

BACKGROUND

Even if understanding of neuronal enteropathies, such as Hirschsprung's disease and functional constipation, has been improved, specialized therapies are still missing. Sacral neuromodulation (SNM) has been established in the treatment of defecation disorders in adults. The aim of the study was to investigate effects of SNM in children and adolescents with refractory symptoms of chronic constipation.

METHODS

A two-centered, prospective trial has been conducted between 2019 and 2022. SNM was applied continuously at individually set stimulation intensity. Evaluation of clinical outcomes was conducted at 3, 6, and 12 months after surgery based on the developed questionnaires and quality of life analysis (KINDLR). Primary outcome was assessed based on predefined variables of fecal incontinence and defecation frequency.

KEY RESULTS

Fifteen patients enrolled in the study and underwent SNM (median age 8.0 years (range 4-17 years)): eight patients were diagnosed with Hirschsprung's disease (53%). Improvement of defecation frequency was seen in 8/15 participants (53%) and an improvement of fecal incontinence in 9/12 patients (75%). We observed stable outcome after 1 year of treatment. Surgical revision was necessary in one patient after electrode breakage. Urinary incontinence was observed as singular side effect of treatment in two patients (13%), which was manageable with the reduction of stimulation intensity.

CONCLUSIONS

SNM shows promising clinical results in children and adolescents presenting with chronic constipation refractory to conservative therapy. Indications for patients with enteral neuropathies deserve further confirmation.

The Effect of the Ganglionic Segment Inflammatory Response to Postoperative Enterocolitis in Hirschsprung Disease

INTRODUCTION

We examined the relationship between proinflammatory cytokines that occur in the inflammatory reaction in the intestine in Hirschsprung disease (HD) and Hirschsprung-associated enterocolitis (HAEC).

METHODS

Thirty cases (M:27, F:3) operated on due to HD. The cases were divided into three groups: group 1 with pre and post operative EC, group 2 with post-operative, and group 3 with pre-operative EC. The intestinal segments were evaluated by immunohistochemistry for interleukin 1 beta (IL-1ß), tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6).

RESULTS

IL-1β staining was significantly higher in the ganglionic zone of groups with enterocolitis compared to the control group (p = 0.012). TNF-α staining in the transitional zone of Group 3 and IL-1β staining in the ganglionic zone of Group 1 was significantly higher than the control group (p = 0.030, p = 0.020).

CONCLUSION

In our study, older age at diagnosis and more than 20% IL-1ß staining in the ganglionic segment were found to be risk factors for HAEC. It is noteworthy that the increase in IL-1ß can be associated with HAEC.

Updates and Challenges in ENS Cell Therapy for the Treatment of Neurointestinal Diseases

Neurointestinal diseases represent a significant challenge in clinical management with current palliative approaches failing to overcome disease and treatment-related morbidity. The recent progress with cell therapy to restore missing or defective components of the gut neuromusculature offers new hope for potential cures. This review discusses the progress that has been made in the sourcing of putative stem cells and the studies into their biology and therapeutic potential. We also explore some of the practical challenges that must be overcome before cell-based therapies can be applied in the clinical setting. Although a number of obstacles remain, the rapid advances made in the enteric neural stem cell field suggest that such therapies are on the near horizon.

Does Length of Extended Resection Beyond Transition Zone Change Clinical Outcome for Hirschsprung Pull-Through?

INTRODUCTION

A proximal resection margin greater than 5 cm from the intra-operative histologically determined transition zone has been deemed necessary to minimize the risk of transition zone pull-through. This extended resection may require the sacrifice of vascular supply and even further bowel resection. The impact of extended proximal resection margin on post-operative complications and functional outcomes is unclear.

METHODS

A retrospective chart review of patients who underwent primary pull-through for Hirschsprung disease at a single institution between January 2008 and December 2022 was performed. An adequate proximal margin was defined by a circumferential normally ganglionated ring and absence of hypertrophic nerves. The extended margin was defined as the total length of proximal colon with normal ganglion cells and without hypertrophic nerves. Fecal incontinence severity was assessed with the Pediatric Fecal Incontinence Severity Score (PFISS).

RESULTS

Eighty seven patients met criteria for inclusion. Median age at primary pull-through was 17 days (IQR 10-92 days), 55% (n = 48) of patients had an extended proximal margin (EPM) ≤ 5 cm, and 45% (n = 39) had an EPM > 5 cm. An EPM ≤5 cm was not associated with increased rates of Hirschsprung associated enterocolitis (≤5 cm 43%, >5 cm 39%, P = 0.701), diversion post pull-through (≤5 cm 10%, >5 cm 5%, P = 0.367) or reoperation for transition zone pull-through (≤5 cm 3%, >5 cm 0%, P = 0.112). EPM ≤5 cm had more frequent involuntary daytime bowel movements (P = 0.041) and more frequent voluntary bowel movements (P = 0.035). There were no differences in other measures of fecal incontinence severity.

CONCLUSIONS

Shorter proximal extended margins beyond the adequate ganglionated margin do not significantly impact post-operative complication rates and have an unclear effect on fecal incontinence.

TYPE OF STUDY

Case Control.

LEVEL OF EVIDENCE

Level III.

The Oxidative Stress and Nervous Distress Connection in Gastrointestinal Disorders

Oxidative stress is increasingly recognized as a central player in a range of gastrointestinal (GI) disorders, as well as complications stemming from therapeutic interventions. This article presents an overview of the mechanisms of oxidative stress in GI conditions and highlights a link between oxidative insult and disruption to the enteric nervous system (ENS), which controls GI functions. The dysfunction of the ENS is characteristic of a spectrum of disorders, including neurointestinal diseases and conditions such as inflammatory bowel disease (IBD), diabetic gastroparesis, and chemotherapy-induced GI side effects. Neurons in the ENS, while essential for normal gut function, appear particularly vulnerable to oxidative damage. Mechanistically, oxidative stress in enteric neurons can result from intrinsic nitrosative injury, mitochondrial dysfunction, or inflammation-related pathways. Although antioxidant-based therapies have shown limited efficacy, recognizing the multifaceted role of oxidative stress in GI diseases offers a promising avenue for future interventions. This comprehensive review summarizes the literature to date implicating oxidative stress as a critical player in the pathophysiology of GI disorders, with a focus on its role in ENS injury and dysfunction, and highlights opportunities for the development of targeted therapeutics for these diseases.

The Crucial Role of the Interstitial Cells of Cajal in Neurointestinal Diseases

Neurointestinal diseases result from dysregulated interactions between the nervous system and the gastrointestinal (GI) tract, leading to conditions such as Hirschsprung's disease and irritable bowel syndrome. These disorders affect many people, significantly diminishing their quality of life and overall health. Central to GI motility are the interstitial cells of Cajal (ICC), which play a key role in muscle contractions and neuromuscular transmission. This review highlights the role of ICC in neurointestinal diseases, revealing their association with various GI ailments. Understanding the functions of the ICC could lead to innovative perspectives on the modulation of GI motility and introduce new therapeutic paradigms. These insights have the potential to enhance efforts to combat neurointestinal diseases and may lead to interventions that could alleviate or even reverse these conditions.

Pediatric intestine and multivisceral transplant

PURPOSE OF REVIEW

Intestinal and multivisceral transplantation (ITx, MVTx) is the cornerstone in treatment of irreversible intestinal failure (IF) and complications related to parenteral nutrition. This review aims to highlight the unique aspects of the subject in pediatrics.

RECENT FINDINGS

Etiology of intestinal failure (IF) in children shares some similarity with adults but several unique considerations when being evaluated for transplantation will be discussed. Owing to significant advancement in IF management and home parenteral nutrition (PN), indication criteria for pediatric transplantation continues to be updated. Outcomes have continued to improve with current long-term patient and graft survival in multicenter registry reports reported at 66.1% and 48.8% at 5 years, respectively. Pediatric specific surgical challenges such abdominal closure, post transplantation outcomes, and quality of life are discussed in this review.

SUMMARY

ITx and MVTx remain lifesaving treatment for many children with IF. However long-term graft function is still a major challenge.

The potential effects and mechanism of echinacoside powder in the treatment of Hirschsprung's Disease

Possible complications, such as intestinal obstruction and inflammation of the intestinal tract, can have a detrimental effect on the prognosis after surgery for Hirschsprung disease. The aim of this study was to investigate the potential targets and mechanisms of action of echinacoside to improve the prognosis of Hirschsprung disease. Genes related to the disease were obtained through analysis of the GSE96854 dataset and four databases: OMIM, DisGeNET, Genecard and NCBI. The targets of echinacoside were obtained from three databases: PharmMapper, Drugbank and TargetNet. The intersection of disease genes and drug targets was validated by molecular docking. The valid docked targets were further explored for their expression by using immunohistochemistry. In this study, enrichment analysis was used to explore the mechanistic pathways involved in the genes. Finally, we identified CA1, CA2, CA9, CA12, DNMT1, RIMS2, RPGRIP1L and ZEB2 as the core targets. Except for ZEB2, which is predominantly expressed in brain tissue, the remaining seven genes show tissue specificity and high expression in the gastrointestinal tract. RIMS2 possesses a high mutation phenomenon in pan-cancer, while a validated ceRNA network of eight genes was constructed. The core genes are involved in several signaling pathways, including the one-carbon metabolic process, carbonate dehydratase activity and others. This study may help us to further understand the pharmacological mechanisms of echinacoside and provide new guidance and ideas to guide the treatment of Hirschsprung disease.

Intestinal failure among adults and children: Similarities and differences

Intestinal failure (IF) is a complex medical condition that is caused by a constellation of disorders, resulting in the gut's inability to adequately absorb fluids and nutrients to sustain hydration, growth, and survival, thereby requiring the use of parenteral fluid and/or nutrition. Significant advancements in intestinal rehabilitation have resulted in improved survival rates for individuals with IF. There are distinct differences, however, related to etiology, adaptive potential and complications, and medical and surgical management when comparing children with adults. The purpose of this review is to contrast the similarities and differences between these two distinct groups and provide insight for future directions, as a growing population of pediatric patients will cross into the adult world for IF management.

CXCR4 and CXCL12 signaling regulates the development of extrinsic innervation to the colorectum

The gastrointestinal tract is innervated by an intrinsic neuronal network, known as the enteric nervous system (ENS), and by extrinsic axons arising from peripheral ganglia. The nerve of Remak (NoR) is an avian-specific sacral neural crest-derived ganglionated structure that extends from the cloaca to the proximal midgut and, similar to the pelvic plexus, provides extrinsic innervation to the distal intestine. The molecular mechanisms controlling extrinsic nerve fiber growth into the gut is unknown. In vertebrates, CXCR4, a cell-surface receptor for the CXCL12 chemokine, regulates migration of neural crest cells and axon pathfinding. We have employed chimeric tissue recombinations and organ culture assays to study the role of CXCR4 and CXCL12 molecules in the development of colorectal innervation. CXCR4 is specifically expressed in nerve fibers arising from the NoR and pelvic plexus, while CXCL12 is localized to the hindgut mesenchyme and enteric ganglia. Overexpression of CXCL12 results in significantly enhanced axonal projections to the gut from the NoR, while CXCR4 inhibition disrupts nerve fiber extension, supporting a previously unreported role for CXCR4 and CXCL12 signaling in extrinsic innervation of the colorectum.

A pilot study characterizing longitudinal changes in fecal microbiota of patients with Hirschsprung-associated enterocolitis

PURPOSE

Hirschsprung disease is a neurointestinal disease that occurs due to failure of enteric neural crest-derived cells to complete their rostrocaudal migration along the gut mesenchyme, resulting in aganglionosis along variable lengths of the distal bowel. Despite the effective surgery that removes the aganglionic segment, children with Hirschsprung disease remain at high risk for developing a potentially life-threatening enterocolitis (Hirschsprung-associated enterocolitis). Although the etiology of this enterocolitis remains poorly understood, several recent studies in both mouse models and in human subjects suggest potential involvement of gastrointestinal microbiota in the underlying pathogenesis of Hirschsprung-associated enterocolitis.

METHODS

We present the first study to exploit the Illumina MiSeq next-generation sequencing platform within a longitudinal framework focused on microbiomes of Hirschsprung-associated enterocolitis in five patients. We analyzed bacterial communities from fecal samples collected at different timepoints starting from active enterocolitis and progressing into remission.

RESULTS

We observed compositional differences between patients largely attributable to variability in age at the time of sample collection. Remission samples across patients exhibited compositional similarity, including enrichment of Blautia, while active enterocolitis samples showed substantial variability in composition.

CONCLUSIONS

Overall, our findings provide continued support for the role of GI microbiota in the pathogenesis of Hirschsprung-associated enterocolitis.

Human Pluripotent Stem Cell-Based Models for Hirschsprung Disease: From 2-D Cell to 3-D Organoid Model

Hirschsprung disease (HSCR) is a complex congenital disorder caused by defects in the development of the enteric nervous system (ENS). It is attributed to failures of the enteric neural crest stem cells (ENCCs) to proliferate, differentiate and/or migrate, leading to the absence of enteric neurons in the distal colon, resulting in colonic motility dysfunction. Due to the oligogenic nature of the disease, some HSCR conditions could not be phenocopied in animal models. Building the patient-based disease model using human induced pluripotent stem cells (hPSC) has opened up a new opportunity to untangle the unknowns of the disease. The expanding armamentarium of hPSC-based therapies provides needed new tools for developing cell-replacement therapy for HSCR. Here we summarize the recent studies of hPSC-based models of ENS in 2-D and 3-D culture systems. These studies have highlighted how hPSC-based models complement the population-based genetic screens and bioinformatic approaches for the discovery of new HSCR susceptibility genes and provide a human model for the close-to-physiological functional studies. We will also discuss the potential applications of these hPSC-based models in translational medicines and their advantages and limitations. The use of these hPSC-based models for drug discovery or cell replacement therapy likely leads to new treatment strategies for HSCR in the future. Further improvements in incorporating hPSC-based models with the human-mouse chimera model and organ-on-a-chip system for establishing a better disease model of HSCR and for drug discovery will further propel us to success in the development of an efficacious treatment for HSCR.

Chronic Chagas Disease-the Potential Role of Reinfections in Cardiomyopathy Pathogenesis

PURPOSE OF THE REVIEW

Chagas disease is a neglected anthropozoonosis of global importance with significant cardiovascular-associated mortality. This review focuses on the Trypanosoma cruzi reinfections' role in chronic Chagas cardiomyopathy pathogenesis. We discuss and summarize the available data related to pathology, pathogenesis, diagnosis, and treatment of reinfections.

RECENT FINDINGS

Reinfections influence the genetic and regional diversity of T. cruzi, tissue tropism, modulation of the host's immune system response, clinical manifestations, the risk for congenital infections, differences in diagnostics performances, response to antiparasitic therapy, and the natural history of the disease. Animal models suggest that reinfections lead to worse outcomes and increased mortality, while other studies showed an association between reinfections and lower parasitemia levels and subsequent infection protection. In some regions, the human risk of reinfections is 14% at 5 years. Evidence has shown that higher anti-T. cruzi antibodies are correlated with an increased rate of cardiomyopathy and death, suggesting that a higher parasite exposure related to reinfections may lead to worse outcomes. Based on the existing literature, reinfections may play a role in developing and exacerbating chronic Chagas cardiomyopathy and are linked to worse outcomes. Control efforts should be redirected to interventions that address structural poverty for the successful and sustainable prevention of Chagas disease.

Paediatric intestinal pseudo-obstruction: a scoping review

Paediatric intestinal pseudo-obstruction (PIPO) encompasses a group of rare disorders in which patients present with the clinical features of bowel obstruction in the absence of mechanical occlusion. The management of PIPO presents a challenge as evidence remains limited on available medical and surgical therapy. Parenteral nutrition is often the mainstay of therapy. Long-term therapy may culminate in life-threatening complications including intestinal failure-related liver disease, central line thrombosis and sepsis. Intestinal transplantation remains the only definitive cure in PIPO but is a complex and resource-limited solution associated with its own morbidity and mortality. We conducted a scoping review to present a contemporary summary of the epidemiology, aetiology, pathophysiology, diagnosis, management and complications of PIPO.Conclusion: PIPO represents a rare disorder that is difficult to diagnose and challenging to treat, with significant morbitity and mortality. The only known cure is intestinal transplantation. What is Known: • Paediatric intestinal pseudo-obstruction is a rare, heterogeneous disorder that confers a high rate of morbidity and mortality • Complications of paediatric intestinal pseudo-obstruction include chronic pain, small intestine bacterial overgrowth and malrotation. Other complications can occur related to its management, such as line infections with parenteral nutrition or cardiac side effects of prokinetic medications What is New: • Progress in medical and surgical therapy in recent years has led to improved patient outcomes • Enteral autonomy has been reported in most patients at as early as 1 month post-transplantation.

Management of pediatric intestinal failure related to short bowel syndrome

Intestinal failure (IF) secondary to short bowel syndrome is a challenging and complex medical condition with significant risk for surgical and medical complications. Significant advancements in the care of this patient population have led to improved survival rates. Due to their intensive medical needs children with IF are at risk for long-term complications that require comprehensive management and close monitoring. The purpose of this paper is to review the available literature emphasizing the surgical aspects of care for children with IF secondary to short bowel syndrome. A key priority in the surgical care of this patient population includes strategies to preserve available bowel and maximize its function. Utilization of novel surgical techniques and autologous bowel reconstruction can have a significant impact on children with IF secondary to short bowel syndrome related to the function of their bowel and ability to achieve enteral autonomy. It is also important to understand the potential long-term complications to ensure strategies are put in place to mitigate risk with early detection to improve long-term outcomes.

Resveratrol and Curcumin for Chagas Disease Treatment—A Systematic Review

Chagas disease (CD) is a neglected protozoan infection caused by Trypanosoma cruzi, which affects about 7 million people worldwide. There are two available drugs in therapeutics, however, they lack effectiveness for the chronic stage—characterized mainly by cardiac (i.e., cardiomyopathy) and digestive manifestations (i.e., megaesophagus, megacolon). Due to the involvement of the immuno-inflammatory pathways in the disease’s progress, compounds exhibiting antioxidant and anti-inflammatory activity seem to be effective for controlling some clinical manifestations, mainly in the chronic phase. Resveratrol (RVT) and curcumin (CUR) are natural compounds with potent antioxidant and anti-inflammatory properties and their cardioprotective effect have been proposed to have benefits to treat CD. Such effects could decrease or block the progression of the disease’s severity. The purpose of this systematic review is to analyze the effectiveness of RVT and CUR in animal and clinical research for the treatment of CD. The study was performed according to PRISMA guidelines and it was registered on PROSPERO (CDR42021293495). The results did not find any clinical study, and the animal research was analyzed according to the SYRCLES risk of bias tools and ARRIVE 2.0 guidelines. We found 9 eligible reports in this study. We also discuss the potential RVT and CUR derivatives for the treatment of CD as well.

How to Heal the Gut's Brain: Regeneration of the Enteric Nervous System

The neural-crest-derived enteric nervous system (ENS) is the intrinsic nervous system of the gastrointestinal (GI) tract and controls all gut functions, including motility. Lack of ENS neurons causes various ENS disorders such as Hirschsprung Disease. One treatment option for ENS disorders includes the activation of resident stem cells to regenerate ENS neurons. Regeneration in the ENS has mainly been studied in mammalian species using surgical or chemically induced injury methods. These mammalian studies showed a variety of regenerative responses with generally limited regeneration of ENS neurons but (partial) regrowth and functional recovery of nerve fibers. Several aspects might contribute to the variety in regenerative responses, including observation time after injury, species, and gut region targeted. Zebrafish have recently emerged as a promising model system to study ENS regeneration as larvae possess the ability to generate new neurons after ablation. As the next steps in ENS regeneration research, we need a detailed understanding of how regeneration is regulated on a cellular and molecular level in animal models with both high and low regenerative capacity. Understanding the regulatory programs necessary for robust ENS regeneration will pave the way for using neural regeneration as a therapeutic approach to treating ENS disorders.

The science of Hirschsprung disease: What we know and where we are headed

The enteric nervous system (ENS) is a rich network of neurons and glial cells that comprise the gastrointestinal tract's intrinsic nervous system and are responsible for controlling numerous complex functions, including digestion, transit, secretion, barrier function, and maintenance of a healthy microbiome. Development of a functional ENS relies on the coordinated interaction between enteric neural crest-derived cells and their environment as the neural crest-derived cells migrate rostrocaudally along the embryonic gut mesenchyme. Congenital or acquired disruption of ENS development leads to various neurointestinal diseases. Hirschsprung disease is a congenital neurocristopathy, a disease of the neural crest. It is characterized by a variable length of distal colonic aganglionosis due to a failure in enteric neural crest-derived cell proliferation, migration, differentiation, and/or survival. In this review, we will review the science of Hirschsprung disease, targeting an audience of pediatric surgeons. We will discuss the basic biology of normal ENS development, as well as what goes awry in ENS development in Hirschsprung disease. We will review animal models that have been integral to studying this disease, as well as current hot topics and future research, including genetic risk profiling, stem cell therapy, non-invasive diagnostic techniques, single-cell sequencing techniques, and genotype-phenotype correlation.

Laparoscopic-assisted Soave procedure for Hirschsprung disease: 10-year experience with 106 cases

Background

The purpose of this study was to summarize the clinical experience and 10 year follow-up results of laparoscopic assisted Soave procedure for the treatment of long-segment Hirschsprung disease (HD).

Methods

From January 2010 to February 2020, 106 children with long-segment HD participated in this study. The laparoscopic-assisted Soave procedure was performed for the treatment of long-segment HD. The follow-up time was two weeks, one month, and three months after the operation, and then every six months to one year.

Results

The operation was successful for all 106 children. All patients were discharged 5–7 days after the operation. The median time in surgery was 150 (100–190) minutes, and the median volume of bleeding was 6 (3–10) ml. The short-term postoperative daily defecation frequency was 4–11 times, 3–7 times within 6 months, and 2–3 times after 6–12 months. Postoperative complications included anastomotic leakage in two cases, perianal dermatitis in 13 cases, anastomotic stenosis in four cases, adhesive bowel obstruction in two cases, enterocolitis in 16 cases, soiling in 11 cases, and constipation recurrence in three cases.

Conclusions

The laparoscopic-assisted Soave procedure is a safe and effective surgical method for treating long-segment HD, and it causes little trauma or bleeding and has a fast postoperative recovery. Yet some complications may occur. Preoperative diagnosis, intraoperative and postoperative standardized processing can reduce the postoperative complications.

Clinical Evaluation of Laparoscopic Surgery for Hirschsprung Disease Combined with Colorectal Anastomosis with a Stapling Technique in Infants

Aim: To evaluate the effect of laparoscopic-assisted resection and colorectal anastomosis with a stapling technique in the treatment of Hirschsprung disease (HSCR) in infants. Methods: From June 2018 to January 2019, 25 cases of HSCR diagnosed by clinical examination and pathology were selected at the Children's Hospital, School of Medicine, Zhejiang University, China. All children were treated with standard laparoscopic-assisted transanal endorectal pull-through surgery (the modified Swenson technique). The short segment type and the typical type with a descending colon-rectum anastomosis were both included. The long segment type had an ascending colon-rectal anastomosis after ascending colon turnover. The colorectal anastomosis was divided into traditional manual anastomosis and straight intraluminal stapler (SIS) anastomosis. According to the different methods of anastomosis, the patients were divided into a traditional group and a SIS group. Age, gender, body weight, operation time, blood loss, postoperative anal exhaust and defecation time, postoperative hospitalization time, and postoperative short-term complications were analyzed retrospectively. Results: A total of 25 children were diagnosed with HSCR. There were 17 boys and 8 girls, and their average age was 10.20 months (interquartile range, 8.60-11.30). Their average body weight was 7.90 kg (interquartile range, 7.50-8.40). There were 17 cases of the typical type, 5 cases of the short segment type, and 3 cases of the long segment type. The different colorectal anastomosis methods were divided into 10 cases in the traditional group and 15 cases in the SIS group. There were no intraoperative complications, wound infections, or anastomotic fistula. Compared with the SIS group, children in the traditional group had an increased operative time (129.5 versus 103.00 minutes; P < .0001), increased intraoperative blood loss (20.00 versus 7.00 mL; P < .0001), increased postoperative hospitalization time (12.00 versus 9.00 days; P = .0003), and increased postoperative defecation time (18.40 versus 13.20 hours; P < .0001). After 6-12 months of follow-up, there was no anastomotic stenosis or enterocolitis in the SIS group. In the traditional group, 1 child had anastomotic stenosis, which improved 6 months after anal dilatation. One case of enterocolitis occurred 4 months after the operation and was cured after enema and infusion. Conclusion: Laparoscopic-assisted resection combined with colorectal anastomosis with the stapling technique in the treatment of HSCR in infants is feasible. It had a short operation time, less bleeding, less trauma, and a rapid recovery of postoperative intestinal function. The anastomosis was smooth, wide, and reliable, and anastomotic fistula and stenosis did not occur.

Clinical Efficacy of an Indwelling Transanal Tube for the Prevention of Anastomotic Leakage After Hirschsprung's Disease: A Single Center Experience with Chinese Patients

Background: The aim of this study was to investigate the clinical effectiveness of an indwelling transanal tube for the prevention of anastomotic leakage (AL) after a radical operation for Hirschsprung's disease (HD). Methods: We retrospectively analyzed the clinical data from 158 patients who had undergone laparoscopic-assisted Soave procedures for HD at our hospital from May 2015 to May 2019. Patients were divided into two groups depending upon whether the anal drainage tube was retained or not retained: an indwelling group (group A, n = 86) and a no-indwelling group (group B, n = 72). Results: All 158 children had a successful operation by a laparoscopic technique. There was no significant difference in the duration of the operation, the length of the incision, the amount of bleeding, or the postoperative hospitalization time between the two groups. Compared with the no-indwelling group, maintaining the transanal tube had significant advantages for preventing incidences of AL (P < .05). The 4-year follow-up showed that the incidence of postoperative enterocolitis with the indwelling transanal tube was significantly lower than in the group without the drainage tube (P < .05). Conclusions: The laparoscopic-assisted Soave procedure with an indwelling transanal tube is a safe and feasible method for the treatment of HD in children. This method can not only drain intestinal contents but also reduce the occurrence of AL.

Avian ceca are indispensable for hindgut enteric nervous system development

The enteric nervous system (ENS), which is derived from enteric neural crest cells (ENCCs), represents the neuronal innervation of the intestine. Compromised ENCC migration can lead to Hirschsprung disease, which is characterized by an aganglionic distal bowel. During the craniocaudal migration of ENCCs along the gut, we find that their proliferation is greatest as the ENCC wavefront passes through the ceca, a pair of pouches at the midgut-hindgut junction in avian intestine. Removal of the ceca leads to hindgut aganglionosis, suggesting that they are required for ENS development. Comparative transcriptome profiling of the cecal buds compared with the interceca region shows that the non-canonical Wnt signaling pathway is preferentially expressed within the ceca. Specifically, WNT11 is highly expressed, as confirmed by RNA in situ hybridization, leading us to hypothesize that cecal expression of WNT11 is important for ENCC colonization of the hindgut. Organ cultures using embryonic day 6 avian intestine show that WNT11 inhibits enteric neuronal differentiation. These results reveal an essential role for the ceca during hindgut ENS formation and highlight an important function for non-canonical Wnt signaling in regulating ENCC differentiation.

Hirschsprung disease and Paediatric Intestinal Pseudo-obstruction

Hirschsprung disease (HSCR) and Paediatric Intestinal Pseudo-obstruction (PIPO) comprise two of the most recognized and severe disorders of gastrointestinal (GI) motility. HSCR is a developmental disorder of the enteric nervous system invariably affecting the large intestine, whereas the majority of PIPO conditions represent congenital disorders of one or more components of the neuromusculature and more diffusely affect the GI tract. Histopathology is deemed the gold standard for the diagnosis of HSCR and, arguably, of PIPO, but, other diagnostic modalities such as manometric and genetic studies have seen recent advances that may increase their utility. Especially for PIPO, management is multidisciplinary and best performed in specialist referral centres. Surgery remains the only viable treatment for HSCR and appears essential to optimize and sustain feeding and viability of intestinal function in PIPO patients. Novel therapies such as neural stem cell transplants show promise for the future.

Disorders of the enteric nervous system - a holistic view

The enteric nervous system (ENS) is the largest division of the peripheral nervous system and closely resembles components and functions of the central nervous system. Although the central role of the ENS in congenital enteric neuropathic disorders, including Hirschsprung disease and inflammatory and functional bowel diseases, is well acknowledged, its role in systemic diseases is less understood. Evidence of a disordered ENS has accumulated in neurodegenerative diseases ranging from amyotrophic lateral sclerosis, Alzheimer disease and multiple sclerosis to Parkinson disease as well as neurodevelopmental disorders such as autism. The ENS is a key modulator of gut barrier function and a regulator of enteric homeostasis. A 'leaky gut' represents the gateway for bacterial and toxin translocation that might initiate downstream processes. Data indicate that changes in the gut microbiome acting in concert with the individual genetic background can modify the ENS, central nervous system and the immune system, impair barrier function, and contribute to various disorders such as irritable bowel syndrome, inflammatory bowel disease or neurodegeneration. Here, we summarize the current knowledge on the role of the ENS in gastrointestinal and systemic diseases, highlighting its interaction with various key players involved in shaping the phenotypes. Finally, current flaws and pitfalls related to ENS research in addition to future perspectives are also addressed.

Biallelic variants in LIG3 cause a novel mitochondrial neurogastrointestinal encephalomyopathy

Abnormal gut motility is a feature of several mitochondrial encephalomyopathies, and mutations in genes such as TYMP and POLG, have been linked to these rare diseases. The human genome encodes three DNA ligases, of which only one, ligase III (LIG3), has a mitochondrial splice variant and is crucial for mitochondrial health. We investigated the effect of reduced LIG3 activity and resulting mitochondrial dysfunction in seven patients from three independent families, who showed the common occurrence of gut dysmotility and neurological manifestations reminiscent of mitochondrial neurogastrointestinal encephalomyopathy. DNA from these patients was subjected to whole exome sequencing. In all patients, compound heterozygous variants in a new disease gene, LIG3, were identified. All variants were predicted to have a damaging effect on the protein. The LIG3 gene encodes the only mitochondrial DNA (mtDNA) ligase and therefore plays a pivotal role in mtDNA repair and replication. In vitro assays in patient-derived cells showed a decrease in LIG3 protein levels and ligase activity. We demonstrated that the LIG3 gene defects affect mtDNA maintenance, leading to mtDNA depletion without the accumulation of multiple deletions as observed in other mitochondrial disorders. This mitochondrial dysfunction is likely to cause the phenotypes observed in these patients. The most prominent and consistent clinical signs were severe gut dysmotility and neurological abnormalities, including leukoencephalopathy, epilepsy, migraine, stroke-like episodes, and neurogenic bladder. A decrease in the number of myenteric neurons, and increased fibrosis and elastin levels were the most prominent changes in the gut. Cytochrome c oxidase (COX) deficient fibres in skeletal muscle were also observed. Disruption of lig3 in zebrafish reproduced the brain alterations and impaired gut transit in vivo. In conclusion, we identified variants in the LIG3 gene that result in a mitochondrial disease characterized by predominant gut dysmotility, encephalopathy, and neuromuscular abnormalities.

Management of Esophageal Dysphagia in Chagas Disease

Chagas disease, caused by the infection of the protozoan parasite Trypanosoma cruzi, has clinical consequences in the heart and digestive tract. The most important changes in the digestive tract occur in the esophagus (megaesophagus) and colon (megacolon). Esophageal dysfunction in Chagas disease results from damage of the esophageal myenteric plexus, with loss of esophageal peristalsis, partial or absent lower esophageal sphincter relaxation, and megaesophagus, which characterizes secondary esophageal achalasia. The treatment options for the disease are similar to those for idiopathic achalasia, consisting of diet and behavior changes, drugs, botulinum toxin, peroral endoscopic myotomy (POEM), pneumatic dilation of the lower esophageal sphincter, laparoscopic Heller myotomy, and esophagectomy. Chagas disease causes a life-threatening cardiopathy, and this should be considered when choosing the most appropriate treatment for the disease. While some options are palliative, for temporary relief of dysphagia (such as drugs, botulinum toxin, and pneumatic dilation), other therapies provide a long-term benefit. In this case, POEM stands out as a modern and successful strategy, with good results in more than 90% of the patients. Esophagectomy is the option in Chagas disease patients with advanced megaesophagus, despite the increased risk of complications. In these cases, peroral endoscopic myotomy may be an option, which needs further evaluation.

Pan-enteric neuropathy and dysmotility are present in a mouse model of short-segment Hirschsprung disease and may contribute to post-pullthrough morbidity

PURPOSE

Hirschsprung disease (HSCR) is characterized by distal intestinal aganglionosis. While surgery is lifesaving, gastrointestinal (GI) motility disorders persist in many patients. Our objective was to determine whether enteric nervous system (ENS) abnormalities exist in the ganglionated portions of the GI tract far proximal to the aganglionic region and whether these are associated with GI dysmotility.

METHODS

Using Ednrb-null mice, a model of HSCR, immunohistochemical analysis was performed to evaluate quantitatively ENS structure in proximal colon, small intestine, and stomach. Gastric emptying and intestinal transit were measured in vivo and small and large bowel contractility was assessed by spatiotemporal mapping ex vivo.

RESULTS

Proximal colon of HSCR mice had smaller ganglia and decreased neuronal fiber density, along with a marked reduction in migrating motor complexes. The distal small intestine exhibited significantly fewer ganglia and decreased neuronal fiber density, and this was associated with delayed small intestinal transit time. Finally, in the stomach of HSCR mice, enteric neuronal packing density was increased and gastric emptying was faster.

CONCLUSIONS

ENS abnormalities and motility defects are present throughout the ganglionated portions of the GI tract in Ednrb-deficient mice. This may explain the GI morbidity that often occurs following pull-through surgery for HSCR.

PHOX2B Immunostaining: A Simple and Helpful Tool for the Recognition of Ganglionic Cells and Diagnosis of Hirschsprung Disease

Hirschsprung disease (HD) is a congenital disorder of the enteric nervous system that occurs in ∼1 in 5000 live births. It is characterized by the absence of ganglionic cells (GCs) in the distal intestine. The diagnosis relies on the thorough analysis of a rectal suction biopsy (RSB), which must show a complete absence of GCs after careful examination of at least 100 serial sections. Such a negative characteristic explains the difficulty of this diagnosis. Moreover, GCs may be immature in very young or preterm born children, making them hard to recognize. Therefore, ancillary techniques have been developed as diagnostic help, such as acetylcholinesterase histochemistry and calretinin immunostaining. These techniques reveal only indirect clues, focusing mainly on the changes in nerve fibers, but not on GCs themselves. As PHOX2B has been shown to be a very specific transcription factor in GCs and in progenitor enteric nerve cells, we have assessed (i) PHOX2B immunostaining in immature enteric ganglia and (ii) the use of PHOX2B immunostaining for the recognition of GCs on RSBs for suspicion of HD. We have observed PHOX2B expression in all GCs, both mature and immature, and its complete absence in Hirschsprung cases. We suggest that the use of PHOX2B immunostaining is of great help (i) in the recognition of GCs on RSBs regardless of their differentiation and therefore (ii) in the diagnosis of HD.

Unexpected High Prevalence of Lymphocytic Infiltrates in Myenteric Ganglions in Intestinal Inertia

Intestinal inertia is a severe form of gut dysmotility that may require surgical resection. Loss of myenteric ganglion cells has been proposed as a possible etiology. Preclinical models have also suggested that virus infection-associated ganglionitis may be an alternative pathogenic factor. We determined to the extent intestinal inertia is associated with the lack of myenteric ganglion cells or ganglionitis using resection specimens from 27 intestinal inertia and 28 colon cancer patients. A hot spot approach with 5 HPFs was used for quantifying inflammatory cells. CD3, CD8, and CD20 immunohistochemistry was used to quantify T and B lymphocytes, along with subtyping the T-lymphocyte population by CD8. None of the intestinal inertia nor control cases showed the absence of myenteric ganglion cells. A total of 15 (55.6%) of the intestinal inertia cases showed inflammatory cell infiltration in the myenteric ganglion cells, compared with only 1 of 28 (3.6%) control cases (P<0.0001 by Fisher exact test). The inertia cases with inflammatory infiltrates were all associated predominantly with lymphocytes, including 3 cases (11.1%) with concurrent eosinophil infiltration, and 1 case (3.7%) with concurrent neutrophil infiltration. Furthermore, all 15 inertia cases with myenteric lymphocytic ganglionitis were associated with T lymphocytes (100%), including 1 case with a subset of concurrent B lymphocytes. The average CD3 count was 3.8 cells/HPF. CD8 immunohistochemical stain showed positive staining in 12 of the 15 cases (80%) with CD8-positive cells ranging from 1 to 8/HPF. In contrast, the only control case with lymphocytic ganglionitis showed mixed B and T lymphocytes and eosinophils. The high prevalence of T-lymphocyte infiltration in the myenteric ganglion in intestinal inertia cases suggests a possible pathogenic role.

How does per-oral endoscopic myotomy compare to Heller myotomy? The Latin American perspective

Background and study aims  Both Heller myotomy (HM) and per-oral endoscopic myotomy (POEM) are efficacious therapies for achalasia. The efficacy and safety of POEM vs HM in Latin America and specifically in patients with Chagas disease is unknown. Patients and methods  Consecutive patients undergoing either HM or POEM for achalasia were included from nine Latin American centers in a prospective registry over 5 years. Technical success was defined as undergoing a successful myotomy. Clinical success was defined as achieving an Eckardt score < 3. Data on demographics, procedure info, Eckardt score, and adverse events (AEs) were collected. Student's t test, Chi squared, and logistic regression analyses were conducted. Results  One hundred thirty-three patients were included (59 male; 44 %; mean age 47). POEM was performed in 69 patients, HM in 64 patients. A total of 35 patients had Chagas disease, 17 of 69 in the POEM group, 18 of 64 in the HM group. Both groups had significant reduction in Eckardt scores ( P  < 0.00001), but successful initial therapy was significantly higher in the POEM group compared to the HM group ( P  = 0.01304). AEs were similar in both group (17 % vs 14 %) and consisted of pneumothorax (n = 3 vs 2), bleeding requiring transfusion (n = 3 vs 2), and mediastinitis (n = 3 vs 1). Hospital stay was longer in the HM group than in the POEM group ( P  < 0.00001). In the Chagas subgroup, post-procedure Eckardt score in the POEM group was significantly reduced by 5.71 points ( P  < 0.00001) versus 1.56 points in the HM group ( P  = 0.042793). Conclusion  Both HM and POEM are efficacious for achalasia, but POEM was associated with higher initial therapy success and shorter hospital stay in Latin America. In Chagas patients with achalasia, POEM was significantly more effective than HM.

Large intestine embryogenesis: Molecular pathways and related disorders (Review)

The large intestine, part of the gastrointestinal tract (GI), is composed of all three germ layers, namely the endoderm, the mesoderm and the ectoderm, forming the epithelium, the smooth muscle layers and the enteric nervous system, respectively. Since gastrulation, these layers develop simultaneously during embryogenesis, signaling to each other continuously until adult age. Two invaginations, the anterior intestinal portal (AIP) and the caudal/posterior intestinal portal (CIP), elongate and fuse, creating the primitive gut tube, which is then patterned along the antero‑posterior (AP) axis and the radial (RAD) axis in the context of left‑right (LR) asymmetry. These events lead to the formation of three distinct regions, the foregut, midgut and hindgut. All the above‑mentioned phenomena are under strict control from various molecular pathways, which are critical for the normal intestinal development and function. Specifically, the intestinal epithelium constitutes a constantly developing tissue, deriving from the progenitor stem cells at the bottom of the intestinal crypt. Epithelial differentiation strongly depends on the crosstalk with the adjacent mesoderm. Major molecular pathways that are implicated in the embryogenesis of the large intestine include the canonical and non‑canonical wingless‑related integration site (Wnt), bone morphogenetic protein (BMP), Notch and hedgehog systems. The aberrant regulation of these pathways inevitably leads to several intestinal malformation syndromes, such as atresia, stenosis, or agangliosis. Novel theories, involving the regulation and homeostasis of intestinal stem cells, suggest an embryological basis for the pathogenesis of colorectal cancer (CRC). Thus, the present review article summarizes the diverse roles of these molecular factors in intestinal embryogenesis and related disorders.

Electroacupuncture to Increase Neuronal Stem Cell Growth

Background: Neuropathic intestinal disorders continue to pose a significant burden, and current treatment options do not target the underlying cellular deficiencies. The goal of this study is to determine whether acupuncture and electroacupuncture (EA) can affect the growth of neuronal cells. Methods: Three groups of Lewis rats received 25 minutes of acupuncture twice a week for 10 weeks. The 3 groups of rats received treatment with either sham acupuncture (SA), real acupuncture (RA), or EA. After 10 weeks of treatment, skin and intestinal tissue were collected and analyzed for histology and mRNA expression of neuronal marker genes. Results: Compared with rats that received SA, rats that received RA and EA showed a significant increase in the mRNA expression levels of multiple neuronal genes in the skin. No significant histologic changes were seen. Conclusions: Acupuncture and EA result in significant changes in the expression of genes implicated as markers for neural stem cells, neural cell development, and neurons. This may, therefore, provide a novel avenue for developing treatments in patients suffering from intestinal aganglionic and neuropathic diseases.

Epigenetic factors Dnmt1 and Uhrf1 coordinate intestinal development

Intestinal tract development is a coordinated process involving signaling among the progenitors and developing cells from all three germ layers. Development of endoderm-derived intestinal epithelium has been shown to depend on epigenetic modifications, but whether that is also the case for intestinal tract cell types from other germ layers remains unclear. We found that functional loss of a DNA methylation machinery component, ubiquitin-like protein containing PHD and RING finger domains 1 (uhrf1), leads to reduced numbers of ectoderm-derived enteric neurons and severe disruption of mesoderm-derived intestinal smooth muscle. Genetic chimeras revealed that Uhrf1 functions both cell-autonomously in enteric neuron precursors and cell-non-autonomously in surrounding intestinal cells, consistent with what is known about signaling interactions between these cell types that promote one another's development. Uhrf1 recruits the DNA methyltransferase Dnmt1 to unmethylated DNA during replication. Dnmt1 is also expressed in enteric neurons and smooth muscle progenitors. dnmt1 mutants have fewer enteric neurons and disrupted intestinal smooth muscle compared to wildtypes. Because dnmt1;uhrf1 double mutants have a similar phenotype to dnmt1 and uhrf1 single mutants, Dnmt1 and Uhrf1 must function together during enteric neuron and intestinal muscle development. This work shows that genes controlling epigenetic modifications are important to coordinate intestinal tract development, provides the first demonstration that these genes influence development of the ENS, and advances uhrf1 and dnmt1 as potential new Hirschsprung disease candidates.

Oesophageal atresia with tracheo-oesophageal fistula, ileal atresia and Hirschsprung's disease: outcome of a rare phenotype

Oesophageal atresia with or without tracheo-oesophageal fistula, ileal atresia and Hirschsprung's disease are surgical malformations of the gastrointestinal tract typically diagnosed early in the neonatal period and varying in severity and prognosis. This report describes a full-term male newborn presenting simultaneous oesophageal atresia with distal tracheo-oesophageal fistula, ileal atresia and Hirschsprung's disease. In addition to the complex types of gastrointestinal malformations involved, the combination of ileal atresia and Hirschsprung's disease, as well as ganglion cells distal to intestinal atresia, resulted in a challenging diagnosis. Despite a successful outcome, the patient presented increased morbidity and prolonged hospitalisation. We highlight some important findings that may aid the early diagnosis of Hirschsprung's disease in this clinical setting. To our knowledge, the association of oesophageal atresia/tracheo-oesophageal fistula, ileal atresia and Hirschsprung's disease has not been previously reported.

Intestinal Electrical Stimulation to Increase the Rate of Peristalsis

BACKGROUND

Pediatric gastrointestinal motility disorders are a large and broad group. Some of these disorders have been effectively treated with electrical stimulation. The goal of our present study is to determine whether the rate of intestinal peristalsis can be increased with electrical stimulation.

METHODS

Juvenile mini-Yucatan pigs were placed under general anesthesia and a short segment of the jejunum was transected. Ultrasound gel was placed inside the segment. The segment of the jejunum was first monitored for 20 min under no stimulation, followed by direct electrical stimulation using a planar electrode. The gel extruded out of the intestine via peristalsis was collected and weighed for each 20-min time interval.

RESULTS

Effective delivery of the current to the intestine was confirmed via direct measurements. When there was no direct intestinal electrical stimulation, an average of 0.40 g of gel was expelled in 20 min, compared to 1.57 g of gel expelled during direct electrical stimulation (P < 0.01).

CONCLUSIONS

Direct intestinal electrical stimulation accelerates the transit of gastrointestinal contents. This approach may be useful in the treatment of a range of pediatric motility disorders.

Stem cells for babies and their surgeons: The future is now

Pediatric surgeons are ideal allies for the translation of basic science including stem cell therapies. In the spirit of Robert E. Gross, of applying creative solutions to pediatric problems with technical expertise, we describe the impending cellular therapies that may be derived from stem and progenitor cells. Understanding the types and capabilities of stem and progenitor cells is important for pediatric surgeons to join and facilitate progress for babies. We are developing an induced pluripotent stem cell therapy for enteric neuropathies such as Hirschsprung disease that might be helpful for children in the near future. Our goals, which we hope to share with other surgeons and scientists, include working to establish safe clinical trials and meeting regulatory standards in a thoughtful way that balances patients need and unknown risks.

Technologies for Live Imaging of Enteric Neural Crest-Derived Cells

Time-lapse imaging of gut explants from embryonic mice in which neural crest-derived cells express fluorescent proteins allows the behavior of enteric neural crest cells to be observed and analyzed. Explants of embryonic gut are dissected, mounted on filter paper supports so the gut retains its tubular three-dimensional structure, and then placed in coverglass bottom culture dishes in tissue culture medium. A stainless steel ring is placed on top of the filter support to prevent movement. Imaging is performed using a confocal microscope in an environmental chamber. A z series of images through the network of fluorescent cells is collected every 3, 5, or 10 min. At the end of imaging, the z series are projected.

Gastrointestinal Neuropathies: New Insights and Emerging Therapies

The bewildering complexity of the enteric nervous system makes it susceptible to develop a wide array of motility disorders, collectively called enteric neuropathies. These gastrointestinal conditions are among the most challenging to manage, mainly given poor characterization of their etiopathophysiology and outcomes. Not surprisingly, therefore, targeted or curative therapies for enteric neuropathies are lacking and management is largely symptomatic. Nonetheless, recent advances in neurogastroenterology have witnessed improvements in established strategies, such as intestinal transplantation and the emergence of new treatments including novel drugs, electrical pacing, and manipulation of fecal microbiota, as well as stem cell and gene therapy.

Estrogen receptor β controls proliferation of enteric glia and differentiation of neurons in the myenteric plexus after damage

Injury to the enteric nervous system (ENS) can cause several gastrointestinal (GI) disorders including achalasia, irritable bowel syndrome, and gastroparesis. Recently, a subpopulation of enteric glial cells with neuronal stem/progenitor properties (ENSCs) has been identified in the adult ENS. ENSCs have the ability of reconstituting the enteric neuronal pool after damage of the myenteric plexus. Since the estrogen receptor β (ERβ) is expressed in enteric glial cells and neurons, we investigated whether a selective ERβ agonist, LY3201, can influence neuronal and glial cell differentiation. Myenteric ganglia from the murine muscularis externa were isolated and cultured in either glial cell medium or neuronal medium. In glial cell medium, the number of glial progenitor cells (Sox10⁺) was increased by fourfold in the presence of LY3201. In the neuronal medium supplemented with an antimitotic agent to block glial cell proliferation, LY3201 elicited a 2.7-fold increase in the number of neurons (neurofilament⁺ or HuC/D⁺). In addition, the effect of LY3201 was evaluated in vivo in two murine models of enteric neuronal damage and loss, namely, high-fat diet and topical application of the cationic detergent benzalkonium chloride (BAC) on the intestinal serosa, respectively. In both models, treatment with LY3201 significantly increased the recovery of neurons after damage. Thus, LY3201 was able to stimulate glial-to-neuron cell differentiation in vitro and promoted neurogenesis in the damaged myenteric plexus in vivo. Overall, our study suggests that selective ERβ agonists may represent a therapeutic tool to treat patients suffering from GI disorders, caused by excessive neuronal/glial cell damage.

Collagen 18 and agrin are secreted by neural crest cells to remodel their microenvironment and regulate their migration during enteric nervous system development

The enteric nervous system (ENS) arises from neural crest cells that migrate, proliferate, and differentiate into enteric neurons and glia within the intestinal wall. Many extracellular matrix (ECM) components are present in the embryonic gut, but their role in regulating ENS development is largely unknown. Here, we identify heparan sulfate proteoglycan proteins, including collagen XVIII (Col18) and agrin, as important regulators of enteric neural crest-derived cell (ENCDC) development. In developing avian hindgut, Col18 is expressed at the ENCDC wavefront, while agrin expression occurs later. Both proteins are normally present around enteric ganglia, but are absent in aganglionic gut. Using chick-mouse intestinal chimeras and enteric neurospheres, we show that vagal- and sacral-derived ENCDCs from both species secrete Col18 and agrin. Whereas glia express Col18 and agrin, enteric neurons only express the latter. Functional studies demonstrate that Col18 is permissive whereas agrin is strongly inhibitory to ENCDC migration, consistent with the timing of their expression during ENS development. We conclude that ENCDCs govern their own migration by actively remodeling their microenvironment through secretion of ECM proteins.