Single-cell guided prenatal derivation of primary fetal epithelial organoids from human amniotic and tracheal fluids.

Isolation of tissue-specific fetal stem cells and derivation of primary organoids is limited to samples obtained from termination of pregnancies, hampering prenatal investigation of fetal development and congenital diseases. Therefore, new patient-specific in vitro models are needed. To this aim, isolation and expansion of fetal stem cells during pregnancy, without the need for tissue samples or reprogramming, would be advantageous. Amniotic fluid (AF) is a source of cells from multiple developing organs. Using single-cell analysis, we characterized the cellular identities present in human AF. We identified and isolated viable epithelial stem/progenitor cells of fetal gastrointestinal, renal and pulmonary origin. Upon culture, these cells formed clonal epithelial organoids, manifesting small intestine, kidney tubule and lung identity. AF organoids exhibit transcriptomic, protein expression and functional features of their tissue of origin. With relevance for prenatal disease modeling, we derived lung organoids from AF and tracheal fluid cells of congenital diaphragmatic hernia fetuses, recapitulating some features of the disease. AF organoids are derived in a timeline compatible with prenatal intervention, potentially allowing investigation of therapeutic tools and regenerative medicine strategies personalized to the fetus at clinically relevant developmental stages.

Generation of human gastric assembloids from primary fetal organoids.

PURPOSE: Understanding human gastric epithelium homeostasis remains partial, motivating the exploration of innovative in vitro models. Recent literature showcases the potential of fetal stem cell-derived organoids in developmental and disease modelling and translational therapies. To scale the complexity of the model, we propose to generate assembloids, aiming to increase gastric maturation to provide new structural and functional insights. METHODS: Human fetal gastric organoids (fGOs) were expanded in 3D Matrigel cultures. Confluent organoid cultures were released from the Matrigel dome and resuspended in a collagen I hydrogel. Subsequently, the organoid mixture was seeded in a ring shape within a 24-well plate and allowed to gelate. The structure was lifted in the medium and cultured in floating conditions, allowing for organoid self-assembling into a gastric assembloid. After 10 days of maturation, the assembloids were characterized by immunostaining and RT-PCR, comparing different fetal developmental stages. RESULTS: Successful generation of human fetal gastric assembloids (fGAs) was achieved using spontaneous self-aggregation within the collagen I hydrogel. Immunostaining analysis of early and late fGAs showed the establishment of apico-basal cell polarity, secretion of gastric mucins, and the presence of chromogranin A in both samples. Transcriptional markers analysis revealed distinct disparities in markers associated with mature cell types between late and early fetal stages. CONCLUSIONS: fGOs can reliably be generated from human fetal samples. This pioneering assembloid approach paves the way for advancing our comprehension of human gastric epithelium homeostasis and its perturbation, offering a better in vitro platform for the study of gastric epithelial development and therapeutic translation.

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.

Building gut from scratch - progress and update of intestinal tissue engineering.

Short bowel syndrome (SBS), a condition defined by insufficient absorptive intestinal epithelium, is a rare disease, with an estimated prevalence up to 0.4 in 10,000 people. However, it has substantial morbidity and mortality for affected patients. The mainstay of treatment in SBS is supportive, in the form of intravenous parenteral nutrition, with the aim of achieving intestinal autonomy. The lack of a definitive curative therapy has led to attempts to harness innate developmental and regenerative mechanisms to engineer neo-intestine as an alternative approach to addressing this unmet clinical need. Exciting advances have been made in the field of intestinal tissue engineering (ITE) over the past decade, making a review in this field timely. In this Review, we discuss the latest advances in the components required to engineer intestinal grafts and summarize the progress of ITE. We also explore some key factors to consider and challenges to overcome when transitioning tissue-engineered intestine towards clinical translation, and provide the future outlook of ITE in therapeutic applications and beyond.

Patient-level costing analysis of paediatric short bowel syndrome care in a specialist tertiary centre.

PURPOSE: To undertake a pilot study estimating patient-level costs of care for paediatric short bowel syndrome (SBS) from the healthcare provider perspective. METHODS: A pilot group of patients with anatomical SBS was selected at a single specialist tertiary centre in the United Kingdom. The Patient Level Information and Costing System (PLICS) was used to extract costing data for all hospital-based activities related to SBS, from the implementation of PLICS in 2016 to April 2021. Patient-specific and pooled data were reported descriptively in per patient-year terms. RESULTS: Five patients had full PLICS data available for the 5-year study period and 2 patients had 4 years of data. The median cost for hospital care of SBS was £52,834 per patient-year (range £1804-£331,489). The key cost drivers were inpatient beds, pharmacy, and staffing costs, which made up > 60% of annual costs. In the first 3 years following index admission (n = 2), there was a steady decline in the annual cost of care to a level comparable with patients with established SBS. CONCLUSION: Patient-level cost of care analysis for SBS is feasible using PLICS. Hospital-related costs vary widely between and within individual patients over time. Key drivers of cost are related to complications of SBS.

Local and systemic responses to SARS-CoV-2 infection in children and adults.

It is not fully understood why COVID-19 is typically milder in children1-3. Here, to examine the differences between children and adults in their response to SARS-CoV-2 infection, we analysed paediatric and adult patients with COVID-19 as well as healthy control individuals (total n = 93) using single-cell multi-omic profiling of matched nasal, tracheal, bronchial and blood samples. In the airways of healthy paediatric individuals, we observed cells that were already in an interferon-activated state, which after SARS-CoV-2 infection was further induced especially in airway immune cells. We postulate that higher paediatric innate interferon responses restrict viral replication and disease progression. The systemic response in children was characterized by increases in naive lymphocytes and a depletion of natural killer cells, whereas, in adults, cytotoxic T cells and interferon-stimulated subpopulations were significantly increased. We provide evidence that dendritic cells initiate interferon signalling in early infection, and identify epithelial cell states associated with COVID-19 and age. Our matching nasal and blood data show a strong interferon response in the airways with the induction of systemic interferon-stimulated populations, which were substantially reduced in paediatric patients. Together, we provide several mechanisms that explain the milder clinical syndrome observed in children.

SARS-CoV-2 infection and replication in human gastric organoids.

COVID-19 typically manifests as a respiratory illness, but several clinical reports have described gastrointestinal symptoms. This is particularly true in children in whom gastrointestinal symptoms are frequent and viral shedding outlasts viral clearance from the respiratory system. These observations raise the question of whether the virus can replicate within the stomach. Here we generate gastric organoids from fetal, pediatric, and adult biopsies as in vitro models of SARS-CoV-2 infection. To facilitate infection, we induce reverse polarity in the gastric organoids. We find that the pediatric and late fetal gastric organoids are susceptible to infection with SARS-CoV-2, while viral replication is significantly lower in undifferentiated organoids of early fetal and adult origin. We demonstrate that adult gastric organoids are more susceptible to infection following differentiation. We perform transcriptomic analysis to reveal a moderate innate antiviral response and a lack of differentially expressed genes belonging to the interferon family. Collectively, we show that the virus can efficiently infect the gastric epithelium, suggesting that the stomach might have an active role in fecal-oral SARS-CoV-2 transmission.

Paediatric gastric organoids as a tool for disease modelling and clinical translation.

PURPOSE: Knowledge of gastric epithelial homeostasis remains incomplete, lacking human-specific models for study. This study establishes a protocol for deriving gastric epithelial organoids from paediatric gastric biopsies, providing a platform for modelling disease and developing translational therapies. METHODS: Full-thickness surgical samples and endoscopic mucosal biopsies were obtained from six patients. Gastric glands were isolated by a chemical chelation protocol and then plated in 3D culture in Matrigel® droplets in chemically defined medium. After formation, organoids were passaged by single cell dissociation or manual disaggregation. Cell composition and epithelial polarity of organoids were assessed by bright field microscopy and immunofluorescence analysis, comparing them to native paediatric gastric tissue. RESULTS: Gastric glands were successfully isolated from all six patients who were aged 4 months to 16 years. Gastric glands from all patients sealed to form spherical gastric organoids. These organoids could be passaged by manual disaggregation or single cell dissociation, remaining proliferative up to 1 year in culture. Organoids retained normal epithelial cell polarity, with the apical surface orientated towards the central lumen. Organoids expressed markers of mature gastric epithelial cell types, except for parietal cells. CONCLUSION: Gastric organoids can be reliably generated from paediatric biopsies and are a representative in vitro model for studying gastric epithelium.

Incidence and outcomes of neuroblastoma in Australian children: A population-based study (1983-2015).

AIM: Neuroblastoma predominantly affects younger children and exhibits heterogeneous behaviour. This study describes incidence and outcomes for neuroblastoma using national population-based data from the Australian Childhood Cancer Registry. METHODS: Deidentified data for all children (0-14 years) diagnosed with neuroblastoma and ganglioneuroblastoma from 1983 to 2015 were extracted. Cause-specific (CSS) and event-free survival were estimated using the cohort method. Adjusted hazard ratios were calculated using a multivariable flexible parametric survival model. Other outcomes investigated included recurrence and second primary malignancies (SPMs). RESULTS: The study cohort comprised 1269 patients. Age-standardised incidence rates remained steady across the study period at approximately 9.5 per million children per year. The proportion of patients with metastatic disease at diagnosis decreased from 63% in 1983-1995 to 42% by 2006-2015 (P < 0.001). CSS and event-free survival both improved significantly over time and reached 75% (95% confidence interval (CI) = 71-79%) and 71% (95% CI = 66-75%) at 5 years post-diagnosis, respectively, for children diagnosed between 2004 and 2013. Of patients achieving full remission, 28% relapsed with subsequent 5-year CSS of only 20%. Although SPMs were rare, neuroblastoma survivors carried a fivefold increased risk compared to cancer rates in the general population (standardised incidence ratio = 5.18, 95% CI = 3.01-8.91), with 7 of the 13 patients (54%) who were diagnosed with an SPM dying within 5 years. CONCLUSIONS: CSS for childhood neuroblastoma has improved substantially over time in Australia, but still remains lower than for most other types of childhood cancer. SPMs are uncommon and carry a better prognosis than relapse of the primary tumour.

Renal tumours in Australian children: 30 years of incidence, outcome and second primary malignancy data from the Australian Childhood Cancer Registry.

AIM: This paper describes the incidence and outcomes of childhood renal malignancies in Australia using national population-based data from the Australian Childhood Cancer Registry. METHODS: De-identified data for children (0-14 years) diagnosed with renal malignancies from 1983 to 2015 inclusive were extracted. Cause-specific (CSS) and event-free survival up to 20 years from diagnosis were estimated using the cohort method. Adjusted excess mortality hazard ratios were calculated using a multivariable flexible parametric survival model. Details relating to second primary malignancies (SPMs) were also examined. RESULTS: There were 1046 children diagnosed with renal malignancies in Australia between 1983 and 2015 (91% nephroblastoma), generating an annual age-standardised incidence rate of 8 per million children, which remained constant over the study period. CSS was 89% (95% confidence interval = 87-91%) and 88% (86-90%) at 5 and 20 years, respectively, and 5-year event-free survival was 82% (80-84%). Five-year CSS did not change over the study period and was highest for nephroblastoma (91%). Of the 94% of patients achieving remission, 15% relapsed and subsequent 5-year CSS was 49% (40%-58%). Eleven children were diagnosed with SPM (standardised incidence ratio = 2.9, 95% confidence interval = 1.6-5.3, P < 0.001), and five of them (45%) died within 5 years of the second diagnosis. CONCLUSIONS: Children treated for renal malignancies in Australia have excellent long-term survival, which is unchanged since 1983. SPMs are uncommon following treatment for childhood renal cancer but carry a poor prognosis. Relapse carries a similarly poor prognosis to SPM but is more common. These data are comparable to registry outcomes in similarly developed nations.

The syndrome of Spigelian hernia and cryptorchidism: a review of paediatric literature.

BACKGROUND/PURPOSE: The purpose of this study is to present a summary of paediatric Spigelian hernia (SH) reported to date, and discuss possible aetiology of SH associated with ipsilateral ectopic testis (SH-ET). METHODS: Search of PubMed, Medline, Embase, and CINAHL was performed using keywords "Spigelian hernia". The following were extracted from articles describing paediatric SH: demographics, site and contents of SH, comorbidities, proposed aetiology, presence of ipsilateral inguinal canal (IC) and gubernaculum (G). RESULTS: There were 78 patients with 88 hernias (69 male, 19 female), including 55 male (19 left, 22 right, 7 bilateral) and 16 female (5 left, 5 right, 3 bilateral) nontraumatic SHs. In nontraumatic male SH, 29 hernias contained testis (10 left, 11 right, 4 bilateral), 15 did not, 10 had no data. Of 29 SH-EH, 15 were lacking IC and G, 3 were missing IC (no G data) and 2 had absent G (no IC data). The combination of SH and cryptorchidism is increasingly recognised as a distinct syndrome. However, there is controversy as to the pathogenic mechanism of this association. We hypothesise SH-ET develops because the G, and therefore IC and line of descent, become cranially 'mislocated' along the mammary line, which overlies the Spigelian fascia. CONCLUSION: SH is rare in children. SH-ET may result by testicular descent to an ectopic site along the embryological mammary line.

Early hypospadias surgery may lead to a better long-term psychosexual outcome.

PURPOSE: We evaluated long-term outcomes in boys treated for hypospadias at Royal Children's Hospital, Melbourne. MATERIALS AND METHODS: Boys who underwent hypospadias surgery were reviewed at ages 13 to 15 years. Surgical results were evaluated using the Hypospadias Objective Scoring Evaluation. Lower urinary tract function was assessed using uroflowmetry and symptom questionnaire. Self-report surveys measured quality of life, patient satisfaction, memory of surgery, psychosexual outcomes and parent satisfaction with care. RESULTS: By Hypospadias Objective Scoring Evaluation score 80% of patients had an excellent surgical outcome. Two independent reviewers assessed lower urinary tract function as normal in 82% and 86% of cases, respectively. Quality of life scores were comparable to published values in normal children. Parents rated the institution highly. Overall 90% and 81% of boys were satisfied with the body and genital appearance, respectively. Those dissatisfied with genital appearance had poorer psychosexual outcomes than satisfied patients. When surgery was completed before age 5 years, boys had no perioperative memories. An association was found between no recollection of surgery and satisfaction with body appearance. CONCLUSIONS: Objective surgical and functional outcomes are excellent after early surgery. Post-repair quality of life is comparable to published data on normal children. Parents are pleased with care. Most boys are satisfied with the body and genital appearance. However, those dissatisfied with genital appearance must be identified in the interest of psychosexual development. The association between no recollection of treatment and satisfaction with body appearance suggests that surgery should be completed before age 5 years when possible to allow the development of good body image in adolescence.