Transplantation of amniotic fluid-derived neural stem cells as a potential novel therapy for Hirschsprung's disease

Human enteric nervous system progenitor transplantation improves functional responses in Hirschsprung disease patient-derived tissue

OBJECTIVE

Hirschsprung disease (HSCR) is a severe congenital disorder affecting 1:5000 live births. HSCR results from the failure of enteric nervous system (ENS) progenitors to fully colonise the gastrointestinal tract during embryonic development. This leads to aganglionosis in the distal bowel, resulting in disrupted motor activity and impaired peristalsis. Currently, the only viable treatment option is surgical resection of the aganglionic bowel. However, patients frequently suffer debilitating, lifelong symptoms, with multiple surgical procedures often necessary. Hence, alternative treatment options are crucial. An attractive strategy involves the transplantation of ENS progenitors generated from human pluripotent stem cells (hPSCs).

DESIGN

ENS progenitors were generated from hPSCs using an accelerated protocol and characterised, in detail, through a combination of single-cell RNA sequencing, protein expression analysis and calcium imaging. We tested ENS progenitors' capacity to integrate and affect functional responses in HSCR colon, after ex vivo transplantation to organotypically cultured patient-derived colonic tissue, using organ bath contractility.

RESULTS

We found that our protocol consistently gives rise to high yields of a cell population exhibiting transcriptional and functional hallmarks of early ENS progenitors. Following transplantation, hPSC-derived ENS progenitors integrate, migrate and form neurons/glia within explanted human HSCR colon samples. Importantly, the transplanted HSCR tissue displayed significantly increased basal contractile activity and increased responses to electrical stimulation compared with control tissue.

CONCLUSION

Our findings demonstrate, for the first time, the potential of hPSC-derived ENS progenitors to repopulate and increase functional responses in human HSCR patient colonic tissue.

Cutting-edge regenerative therapy for Hirschsprung disease and its allied disorders

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

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.

Opportunities for novel diagnostic and cell-based therapies for Hirschsprung disease

Despite significant progress in our understanding of the etiology and pathophysiology of Hirschsprung disease (HSCR), early and accurate diagnosis and operative management can be challenging. Moreover, long-term morbidity following surgery, including fecal incontinence, constipation, and Hirschsprung-associated enterocolitis (HAEC), remains problematic. Recent advances applying state-of-the art imaging for visualization of the enteric nervous system and utilizing neuronal stem cells to replace the missing enteric neurons and glial cells offer the possibility of a promising new future for patients with HSCR. In this review, we summarize recent research advances that may one day offer novel approaches for the diagnosis and management of this disease.

Amniotic fluid-derived stem cell potential for therapeutic and surgical use: A review of the literature

OBJECTIVE

Spina bifida is a debilitating neutral tube defect affecting many infants. The impact and severity of spina bifida depends on whether the patient exhibits a closed defect, spina bifida occulta, or an open defect, spina bifida aperta. Patients with spina bifida have physical and mental disabilities which merit further research into less invasive, more successful treatments. In addition to serving as protection for the growing fetus and facilitating nutrient exchange, amniotic fluid (AF) is a rich source of a mixed population of stem cells. As such, in vitro culture of AF-derived stem cells has shown promise among therapeutic and surgical applications. We present a critical evaluation of the current preclinical efforts, amniotic fluid-derived stem cell (AFSC) culture process, and the subsequent therapeutic application, with a focus on improvements for spina bifida outcomes in the pediatric patient population.

METHOD

An evidence - based literature review to investigate the current literature surrounding AFSC culture and use, with an emphasis on the benefits for spina bifida treatment.

RESULTS

47 literature sources from PubMed and three studies from ClinicalTrials.gov.

CONCLUSION

This review synthesizes the current literature, which shows promising data on AFSC pluripotency, as well as successful in utero coverage from AFSC - supported environments in a multitude of animal models.

Regenerative medicine for childhood gastrointestinal diseases

Several paediatric gastrointestinal diseases result in life-shortening organ failure. For many of these conditions, current therapeutic options are suboptimal and may not offer a cure. Regenerative medicine is an inter-disciplinary field involving biologists, engineers, and clinicians that aims to produce cell and tissue-based therapies to overcome organ failure. Exciting advances in stem cell biology, materials science, and bioengineering bring engineered gastrointestinal cell and tissue therapies to the verge of clinical trial. In this review, we summarise the requirements for bioengineered therapies, the possible sources of the various cellular and non-cellular components, and the progress towards clinical translation of oesophageal and intestinal tissue engineering to date.

Dynamic integration of enteric neural stem cells in ex vivo organotypic colon cultures

Enteric neural stem cells (ENSC) have been identified as a possible treatment for enteric neuropathies. After in vivo transplantation, ENSC and their derivatives have been shown to engraft within colonic tissue, migrate and populate endogenous ganglia, and functionally integrate with the enteric nervous system. However, the mechanisms underlying the integration of donor ENSC, in recipient tissues, remain unclear. Therefore, we aimed to examine ENSC integration using an adapted ex vivo organotypic culture system. Donor ENSC were obtained from Wnt1^cre/+;R26R^YFP/YFP mice allowing specific labelling, selection and fate-mapping of cells. YFP⁺ neurospheres were transplanted to C57BL6/J (6–8-week-old) colonic tissue and maintained in organotypic culture for up to 21 days. We analysed and quantified donor cell integration within recipient tissues at 7, 14 and 21 days, along with assessing the structural and molecular consequences of ENSC integration. We found that organotypically cultured tissues were well preserved up to 21-days in ex vivo culture, which allowed for assessment of donor cell integration after transplantation. Donor ENSC-derived cells integrated across the colonic wall in a dynamic fashion, across a three-week period. Following transplantation, donor cells displayed two integrative patterns; longitudinal migration and medial invasion which allowed donor cells to populate colonic tissue. Moreover, significant remodelling of the intestinal ECM and musculature occurred upon transplantation, to facilitate donor cell integration within endogenous enteric ganglia. These results provide critical evidence on the timescale and mechanisms, which regulate donor ENSC integration, within recipient gut tissue, which are important considerations in the future clinical translation of stem cell therapies for enteric disease.

Enteric neural stem cell therapies for enteric neuropathies

BACKGROUND

Enteric neuropathies exist as a wide range of human disorders which impact on gastrointestinal motility. Current standard therapies for enteric neuropathies are limited to surgical resection or manipulation (eg, myotomy) of affected gut segments or medical management including both therapy (eg, prokinetic pharmacotherapy) and support such as parenteral nutrition. However, such treatments often result in poor prognosis and significant morbidity. The current limitations in treatment options for enteric neuropathies underline the need for alternative approaches to treat these devastating diseases. Recent advances have highlighted the potential of enteric neural stem cells as a possible treatment option for regenerative medicine, in such cases.

PURPOSE

The purpose of this review is to provide an up-to-date synopsis of the enteric neural stem cell research field. Here, we review in detail the initial characterization of enteric neural stem cells, early preclinical studies validating their use in murine models through to the most recent findings of therapeutic rescue of diseased gut tissue. We additionally pose a number of questions regarding these recent findings which will need to be addressed prior to clinical translation of this exciting cellular therapeutic.

Amniotic Fluid Stem Cells for the Treatment of Surgical Disorders in the Fetus and Neonate

Over the past decade, amniotic fluid‐derived stem cells have emerged as a novel experimental approach aimed at improving outcomes in children with congenital anomalies, including spina bifida, heart defects, and diaphragmatic hernia. Interest in these cells for the treatment of prenatally diagnosed diseases has arisen based on numerous studies demonstrating the relative ease of harvesting an abundant quantity of amniocytes from a small aliquot of fluid, the unique properties of amniocytes themselves, and the beneficial effects of amniotic fluid‐derived stem cells in experimental animal models. This report gives a brief overview of the rationale and current status of amniotic fluid stem cell‐based therapies, focusing on its relevance to birth defects affecting the fetus and neonate. The author proposes a roadmap for further study that would be required prior to clinical application of amniotic fluid stem cell technologies. stem cells translational medicine2018;7:767–773

Stem cells and necrotizing enterocolitis: A direct comparison of the efficacy of multiple types of stem cells

PURPOSE

Necrotizing enterocolitis (NEC) is a leading cause of gastrointestinal morbidity and mortality in premature infants. While studies have shown potential for stem cell (SC) therapy in experimental NEC, no study has compared different SC side-by-side. Our purpose was to determine whether one type of SC may more effectively treat NEC than others.

METHODS

Four SC were compared: (1) amniotic fluid-derived mesenchymal SC (AF-MSC); (2) amniotic fluid-derived neural SC (AF-NSC); (3) bone marrow-derived mesenchymal SC (BM-MSC); and (4) neonatal enteric neural SC (E-NSC). Using an established rat model of NEC, pups delivered prematurely received an intraperitoneal injection of SC. Control pups were injected with PBS. Additional controls were breast-fed by surrogates and not subjected to experimental NEC. Intestinal tissue was graded histologically.

RESULTS

NEC incidence was: PBS, 61.3%; breast-fed unstressed, 0%; AF-MSC, 19.1%; BM-MSC, 22.9%; AF-NSC, 18.9%; E-NSC 22.2%. All groups demonstrated statistical significance (p<0.05) compared to controls, and there was no difference between SC groups.

CONCLUSION

All four SC groups reduced the incidence and severity of experimental NEC equivalently. AF-MSC may be preferable because of availability of AF at delivery and ease of expansion, increasing potential for clinical translation.

LEVEL OF EVIDENCE

V (Animal study).

Current status of Hirschsprung's disease: based on a nationwide survey of Japan

PURPOSE

The diagnosis and surgical treatments of Hirschsprung's disease (HD) have undergone various changes in the last few decades because of establishment of laparoscopic procedures. A retrospective nationwide survey for 4 decades was performed to study the changing profile of HD in Japan.

METHODS

The patient data were collected in 4 phases: Group 1, between 1978 and 1982; Group 2, between 1988 and 1992; Group 3, between 1998 and 2002; and Group 4, between 2008 and 2012.

RESULTS

The incidence and the male/female ratio remained almost the same over time (1/4, 895 in newborns and 2.9:1 in Group 4). The patients with a family history increased to 7.1% in Group 4, in comparison to 2.8-6.0% in other groups. Regarding the extent of aganglionosis, sigmoid colon increased to 63.1% in Group 4, compared to 51.9% in Group 3. Manometry was performed less frequently in Group 4 (45.8%) than in Group 3 (66.1%). Transanal endorectal pull-through (TAEPT) was the most popular operation in Group 4 (49.6%). In addition, laparoscopy-assisted operations increased to 46.9% in Group 4, in comparison to 29.7% in Group 3. The incidence of preoperative enterocolitis and the mortality rate in Group 4 were 17.2% and 2.4%, respectively, and were markedly decreased in comparison to Group 1 (29.2% and 6.5%, respectively). The mortality rate decreased over time to 2.4% in Group 4. Over the last decade, there has been remarkable improvement in the mortality rate associated with the small intestine (aganglionosis extending orally to more than 30 cm of the terminal ileum). The rates were 25.5% in Group 4, 53.6% in Group 1, 33.3% in Group 2, and 35.5% in Group 3. In addition, the mortality rates of the remaining aganglionosis subgroups also improved.

CONCLUSION

Primary operations without laparotomy, including TAEPT and laparoscopy-assisted operations, have become the first choice for the definitive surgical treatment of HD in Japan. The mortality rate has decreased over time. However, the mortality rate of small intestinal aganglionosis is still relatively high. The development of new treatment strategy for small intestinal aganglionosis is called for.

Evaluating the efficacy of different types of stem cells in preserving gut barrier function in necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in premature infants. Increased intestinal permeability is central to NEC development. We have shown that stem cells (SCs) can reduce the incidence and severity of NEC. Our current goal was to investigate the efficacy of four different types of SC in preservation of gut barrier function during NEC.

MATERIALS AND METHODS

We compared (1) amniotic fluid-derived mesenchymal SC, (2) bone marrow-derived mesenchymal SC, (3) amniotic fluid-derived neural SC, and (4) enteric neural SC. Premature rat pups received an intraperitoneal injection of 2 × 10⁶ SC or phosphate-buffered saline only and were then subjected to experimental NEC. Control pups were breastfed and not subjected to NEC. After 48 h, animals received a single enteral dose of fluorescein isothiocyanate -labeled dextran (FD70), were sacrificed 4 h later, and serum FD70 concentrations determined.

RESULTS

Compared to breastfed, unstressed pups with intact gut barrier function and normal intestinal permeability (serum FD70 concentration 2.22 ± 0.271 μg/mL), untreated pups exposed to NEC had impaired barrier function with significantly increased permeability (18.6 ± 4.25 μg/mL, P = 0.047). Pups exposed to NEC but treated with SC had significantly reduced intestinal permeability: Amniotic fluid-derived mesenchymal SC (9.45 ± 1.36 μg/mL, P = 0.017), bone marrow-derived mesenchymal SC (6.73 ± 2.74 μg/mL, P = 0.049), amniotic fluid-derived neural SC (8.052 ± 1.31 μg/mL, P = 0.0496), and enteric neural SC (6.60 ± 1.46 μg/mL, P = 0.033).

CONCLUSIONS

SCs improve gut barrier function in experimental NEC. Although all four types of SC reduce permeability equivalently, SC derived from amniotic fluid may be preferable due to availability at delivery and ease of culture, potentially enhancing clinical translation.