Anorectal malformation: the etiological factors

High altitude exposure and the birth prevalence of congenital anomalies in newborns with Down syndrome

BACKGROUND

Individuals with Down syndrome are inherently predisposed to congenital anomalies due to a susceptible genotype that may interact with environmental factors. High-altitude exposure, in particular, has been linked to an increased risk of congenital heart disease. However, few studies have explored environmental risk factors for congenital anomalies in this population, and the specific impact of high altitude remains under-investigated. This study aimed to evaluate maternal and environmental risk factors, including high-altitude residence, on the prevalence of congenital anomalies in newborns with Down syndrome.

METHODS

We conducted a cross-sectional study at two specialized genetic centers in Bolivia, including patients referred from various regions of the country. Data on clinical history and habitual residence were extracted from medical records to identify potential risk factors. The primary outcome was the presence of major congenital anomalies. Univariate and multivariate logistic regression analyses were performed to assess the association between risk factors and congenital anomalies.

RESULTS

A total of 301 Down syndrome cases were included, of which 182 (60.5 %) presented with major congenital anomalies, with congenital heart disease and gastrointestinal anomalies being the most prevalent. Maternal age, high-altitude exposure, preeclampsia, and consanguinity were significantly associated with an increased risk of congenital anomalies (all p < 0.05). Furthermore, stratified analysis revealed that high altitude was a significant risk factor for specific anomalies: patent ductus arteriosus (OR: 5.82, 95 % CI: [1.68-36.65], p = 0.02) and anorectal anomalies (OR: 5.29, 95 % CI: [1.52-33.45], p = 0.03).

CONCLUSION

Our findings indicate that both maternal and environmental factors, particularly high-altitude exposure, play a crucial role in the development of congenital anomalies in newborns with Down syndrome. These results underscore the need for enhanced surveillance and tailored clinical management in high-risk populations, as well as further research into preventive strategies to mitigate these risks.

Study of the enteric and motor inervation, pelvic musculature, and alterations in the sacral region of rat fetuses with ethylenethiourea-induced anorectal anomaly

PURPOSE

The aims of this work were to induce anorectal anomaly in rat fetuses via the planned administration of ethylenethiourea (ETU), and to study fetuses exhibiting anorectal malformation, as well as apparently normal fetuses submitted to the effect of ETU.

METHODS

Time-mated pregnant Wistar rats were randomly divided into control and experimental groups. On gestational day 10, the experimental group received 10% ETU (130 mg/kg) by gavage, whereas the control rats received vehicle only. The embryos were harvested by cesarean section on gestational day 21. The fetuses exposed to ETU were divided into two groups: affected (without any clear anorectal alterations); and the malformed (with anorectal anomaly). The neuromotor plates were identified by immunohistochemistry with acetylcholinesterase, and alterations in the sacral region were evaluated by histological and morphometric studies.

RESULTS

We used 43 control fetuses, 82 affected fetuses, and 118 malformed fetuses in this study. The most frequent associated macroscopic anomalies were spina bifida (55 fetuses), encephalocele (20), and alterations in the lower limbs (5). The sacroiliac was malformed in 45% of the affected fetuses and in 53.2 % of the malformed fetuses.

CONCLUSION

ETU leads to a reduced number of motor neurons in the pelvic musculature of both the malformed and the affected rats. The enteric neurons are altered in the malformed fetuses, but not in the affected ones. Both the affected and malformed rats exhibit sacral alterations that do not interfere with neurons.

Can Anorectal Stenosis be Managed With Dilations Alone? A PCPLC Review

PURPOSE

Congenital anorectal stenosis is managed by dilations or operative repair. Recent studies now propose use of dilations as the primary treatment modality to potentially defer or eliminate the need for surgical repair. We aim to characterize the management and outcomes of these patients via a multi-institutional review using the Pediatric Colorectal and Pelvic Learning Consortium (PCPLC) registry.

METHODS

A retrospective database review was performed using the PCPLC registry. The patients were evaluated for demographics, co-morbidities, diagnostic work-up, surgical intervention, current bowel management, and complications.

RESULTS

64 patients with anal or rectal stenosis were identified (57 anal, 7 rectal) from a total of 14 hospital centers. 59.6% (anal) and 42.9% (rectal) were male. The median age was 3.2 (anal) and 1.9 years (rectal). 11 patients with anal stenosis also had Currarino Syndrome with 10 of the 11 patients diagnosed with a presacral mass compared to only one rectal stenosis with Currarino Syndrome and a presacral mass. 13 patients (22.8%, anal) and one (14.3%, rectal) underwent surgical correction. Nine patients (8 anal, 1 rectal) underwent PSARP. Other procedures performed were cutback anoplasty and anterior anorectoplasty. The median age at repair was 8.4 months (anal) and 10 days old (rectal). One patient had a wound complication in the anal stenosis group. Bowel management at last visit showed little differences between groups or treatment approach.

CONCLUSION

The PCPLC registry demonstrated that these patients can often be managed successfully with dilations alone. PSARP is the most common surgical repair chosen for those who undergo surgical repair.

LEVEL OF EVIDENCE

III.

Rack1-mediated ferroptosis affects hindgut development in rats with anorectal malformations: Spatial transcriptome insights

Anorectal malformation (ARM), a common congenital anomaly of the digestive tract, is a result of insufficient elongation of the urorectal septum. The cytoplasmic protein Receptor of Activated C-Kinase 1 (Rack1) is involved in embryonic neural development; however, its role in embryonic digestive tract development and ARM formation is unexplored. Our study explored the hindgut development and cell death mechanisms in ARM-affected rats using spatial transcriptome analysis. We induced ARM in rats by administering ethylenethiourea via gavage on gestational day (GD) 10. On GDs 14-16, embryos from both normal and ARM groups underwent spatial transcriptome sequencing, which identified key genes and signalling pathways. Rack1 exhibited significant interactions among differentially expressed genes on GDs 15 and 16. Reduced Rack1 expression in the ARM-affected hindgut, verified by Rack1 silencing in intestinal epithelial cells, led to increased P38 phosphorylation and activation of the MAPK signalling pathway. The suppression of this pathway downregulated Nqo1 and Gpx4 expression, resulting in elevated intracellular levels of ferrous ions, reactive oxygen species (ROS) and lipid peroxides. Downregulation of Gpx4 expression in the ARM hindgut, coupled with Rack1 co-localisation and consistent mitochondrial morphology, indicated ferroptosis. In summary, Rack1, acting as a hub gene, modulates ferrous ions, lipid peroxides, and ROS via the P38-MAPK/Nqo1/Gpx4 axis. This modulation induces ferroptosis in intestinal epithelial cells, potentially influencing hindgut development during ARM onset.

Spatial transcriptomics reveals gene interactions and signaling pathway dynamics in rat embryos with anorectal malformation

Anorectal malformation (ARM) is a prevalent early pregnancy digestive tract anomaly. The intricate anatomy of the embryonic cloaca region makes it challenging for traditional high-throughput sequencing methods to capture location-specific information. Spatial transcriptomics was used to sequence libraries of frozen sections from embryonic rats at gestational days (GD) 14 to 16, covering both normal and ARM cases. Bioinformatics analyses and predictions were performed using methods such as WGCNA, GSEA, and PROGENy. Immunofluorescence staining was used to verify gene expression levels. Gene expression data was obtained with anatomical annotations of clusters, focusing on the cloaca region's location-specific traits. WGCNA revealed gene modules linked to normal and ARM cloacal anatomy development, with cooperation between modules on GD14 and GD15. Differential gene expression profiles and functional enrichment were presented. Notably, protein levels of Pcsk9, Hmgb2, and Sod1 were found to be downregulated in the GD15 ARM hindgut. The PROGENy algorithm predicted the activity and interplay of common signaling pathways in embryonic sections, highlighting their synergistic and complementary effects. A competing endogenous RNA (ceRNA) regulatory network was constructed from whole transcriptome data. Spatial transcriptomics provided location-specific cloaca region gene expression. Diverse bioinformatics analyses deepened our understanding of ARM's molecular interactions, guiding future research and providing insights into gene regulation in ARM development.

Multivariate logistic regression analysis of risk factors for birth defects: a study from population-based surveillance data

OBJECTIVE

To explore risk factors for birth defects (including a broad range of specific defects).

METHODS

Data were derived from the Population-based Birth Defects Surveillance System in Hunan Province, China, 2014-2020. The surveillance population included all live births, stillbirths, infant deaths, and legal termination of pregnancy between 28 weeks gestation and 42 days postpartum. The prevalence of birth defects (number of birth defects per 1000 infants) and its 95% confidence interval (CI) were calculated. Multivariate logistic regression analysis (method: Forward, Wald, α = 0.05) and adjusted odds ratios (ORs) were used to identify risk factors for birth defects. We used the presence or absence of birth defects (or specific defects) as the dependent variable, and eight variables (sex, residence, number of births, paternal age, maternal age, number of pregnancies, parity, and maternal household registration) were entered as independent variables in multivariate logistic regression analysis.

RESULTS

Our study included 143,118 infants, and 2984 birth defects were identified, with a prevalence of 20.85% (95%CI: 20.10-21.60). Multivariate logistic regression analyses showed that seven variables (except for parity) were associated with birth defects (or specific defects). There were five factors associated with the overall birth defects. The risk factors included males (OR = 1.49, 95%CI: 1.39-1.61), multiple births (OR = 1.44, 95%CI: 1.18-1.76), paternal age < 20 (OR = 2.20, 95%CI: 1.19-4.09) or 20-24 (OR = 1.66, 95%CI: 1.42-1.94), maternal age 30-34 (OR = 1.16, 95%CI: 1.04-1.29) or > = 35 (OR = 1.56, 95%CI: 1.33-1.81), and maternal non-local household registration (OR = 2.96, 95%CI: 2.39-3.67). Some factors were associated with the specific defects. Males were risk factors for congenital metabolic disorders (OR = 3.86, 95%CI: 3.15-4.72), congenital limb defects (OR = 1.34, 95%CI: 1.14-1.58), and congenital kidney and urinary defects (OR = 2.35, 95%CI: 1.65-3.34). Rural areas were risk factors for congenital metabolic disorders (OR = 1.21, 95%CI: 1.01-1.44). Multiple births were risk factors for congenital heart defects (OR = 2.09, 95%CI: 1.55-2.82), congenital kidney and urinary defects (OR = 2.14, 95%CI: 1.05-4.37), and cleft lip and/or palate (OR = 2.85, 95%CI: 1.32-6.15). Paternal age < 20 was the risk factor for congenital limb defects (OR = 3.27, 95%CI: 1.10-9.71), 20-24 was the risk factor for congenital heart defects (OR = 1.64, 95%CI: 1.24-2.17), congenital metabolic disorders (OR = 1.56, 95%CI: 1.11-2.21), congenital limb defects (OR = 1.61, 95%CI: 1.14-2.29), and congenital ear defects (OR = 2.13, 95%CI: 1.17-3.89). Maternal age < 20 was the risk factor for cleft lip and/or palate (OR = 3.14, 95%CI: 1.24-7.95), 30-34 was the risk factor for congenital limb defects (OR = 1.37, 95%CI: 1.09-1.73), >=35 was the risk factor for congenital heart defects (OR = 1.51, 95%CI: 1.14-1.99), congenital limb defects (OR = 1.98, 95%CI: 1.41-2.78), and congenital ear defects (OR = 1.82, 95%CI: 1.06-3.10). Number of pregnancies = 2 was the risk factor for congenital nervous system defects (OR = 2.27, 95%CI: 1.19-4.32), >=4 was the risk factor for chromosomal abnormalities (OR = 2.03, 95%CI: 1.06-3.88) and congenital nervous system defects (OR = 3.03, 95%CI: 1.23-7.47). Maternal non-local household registration was the risk factor for congenital heart defects (OR = 3.57, 95%CI: 2.54-5.03), congenital metabolic disorders (OR = 1.89, 95%CI: 1.06-3.37), congenital limb defects (OR = 2.94, 95%CI: 1.86-4.66), and congenital ear defects (OR = 3.26, 95%CI: 1.60-6.65).

CONCLUSION

In summary, several risk factors were associated with birth defects (including a broad range of specific defects). One risk factor may be associated with several defects, and one defect may be associated with several risk factors. Future studies should examine the mechanisms. Our findings have significant public health implications as some factors are modifiable or avoidable, such as promoting childbirths at the appropriate age, improving the medical and socio-economic conditions of non-local household registration residents, and devoting more resources to some specific defects in high-risk groups, which may help reducing birth defects in China.

Bowel function and features of bowel dysfunction in preschool children with anorectal malformation type rectoperineal and rectovestibular fistula

Anorectal malformations (ARMs) of the rectoperineal and rectovestibular fistula type (RPF/RVF) generally have a good prognosis but may be accompanied by bowel dysfunction, especially constipation. Bowel dysfunction in preschoolers may persist into adolescence and adulthood, exerting a negative effect on their quality of life. This study was designed to evaluate bowel function and identify the features of bowel dysfunction in preschoolers with RPF/RVF across type and sex differences. A total of 159 preschoolers with RPF/RVF (male RPF group, n = 95; female RPF group, n = 26; RVF, n = 38) and 128 normal control preschoolers (control group, n = 128; female control group, n = 35), according to the bowel function score (BFS) obtained through a questionnaire survey, the BFS items in the questionnaire, and the clinical characteristics of patients were compared among groups. The rates of bowel dysfunction (BFS < 17) were 27.2% and 50.0% in the RPF and RVF groups, respectively. Normal rates of BFS items, namely, ability to hold back defecation, feels/reports of the urge to defecate, frequency of defecation, and constipation, in the RPF and RVF groups were significantly lower than those in the control and female control groups (all p < 0.05). After subgroup analysis among the male RPF, female RPF, and RVF groups, higher rates of normal bowel function and ability to hold back defecation were found in the male RPF group than in the female RPF and RVF groups (p < 0.05). Normal rates of feels/reports of the urge to defecate were higher in the male and female RPF groups than in the RVF group (all p < 0.05). The rate of never soiling in the male RPF group was significantly higher than that in the RVF group (p < 0.05).  Conclusions: In patients with RPF/RVF, bowel dysfunction is still prevalent, characterized by inadequate ability to hold back defecation, inability to feel/report the urge to defecate, soil, less frequent defecation, and constipation. However, male RPF patients had better overall bowel function than female RPF or RVF patients, including more adequate ability to hold back defecation and feels/reports of the urge to defecate and slighter soiling, which may be linked to early age at surgery, low occurrences of low sacral ratio, and tethered cord in male RPF.  Trial registration: This study was retrospectively registered in ClinicalTrials.gov on 09/01/2023 (NCT05716230). What is Known: • Rectoperineal and rectovestibular fistula (RPF/RVF) of the anorectal malformation (ARM) type has a good prognosis but may cause bowel dysfunction, especially constipation. • Bowel dysfunction at preschool age may lead to social and psychological disorders that undermine the quality of life in adolescence and adulthood. What is New: • Bowel function in preschoolers with RPF/RVF was deeply evaluated in a relatively large number of patients and normal control children. • Features of bowel dysfunction in RPF/RVF preschoolers across type and gender differences were identified in this study.

Anorectal Malformations: The Pivotal Role of the Good Clinical Practice

Anorectal malformations (ARM) without a fistula are a rare congenital condition. Although may seem more simple to repair compared with ARM with fistulas, surgery has proved to be challenging. We report the case of a newborn who presented a well-formed anus and normal genitalia; a blind-ending anal canal was detected after the insertion of a rectal probe, thus allowing the diagnosis of ARM. Anal probing straight after birth avoids the possible complications related to intestinal obstruction due to a missed diagnosis of ARM. Examination of the perineal region is an important step in the evaluation of the newborn and represents the tool for a prompt identification of ARM. Adding anal probing to accurate inspection perineum is a good clinical practice and should always be performed even in presence of a normal-looking perineum.

CircJag1 promotes apoptosis of ethylene thiourea-exposed anorectal malformations through sponging miR-137-3p by regulating Sox9 and suppressing Wnt/β-catenin pathway during the hindgut development of rat embryos

Anorectal malformations (ARMs) are common birth defects involving congenital structural anomalies of the gastrointestinal tract. As an important component of non-coding RNAs, circular RNAs (circRNAs) widely participate in the digestive system development; however, the specific molecular mechanism of their involvement in ARM occurrence remains obscure. Herein, we generated rat models of ARMs induced by ethylene thiourea. A novel circRNA (circJag1) was screened and identified by RNA-Seq, which is remarkably upregulated in hindgut tissues of ARM rat embryos. In vivo experiments, colocation analysis via fluorescence in situ hybridization, and immunofluorescence further demonstrated that the disordered circJag1/miR-137-3p/Sox9 expression caused a spatiotemporal imbalance in the urorectal septum (URS) of ARMs. In vitro, functional assays confirmed that circJag1 upregulation resulted in the degradation of nuclear β-catenin, C-myc, and Cyclin D1 in rat intestinal epithelial cells, as well as the promotion of apoptosis and suppression of cell proliferation. Mechanistically, dual-luciferase reporter assay and RNA immunoprecipitation assay indicated that circJag1 acted as a miR-137-3p sponge, thereby inhibiting its repressive effect on its target Sox9. Further experiments showed that a loss of Sox9 abolished the circJag1-mediated increase in apoptosis. In conclusion, aberrantly high circJag1 expression promotes epithelial apoptosis by suppressing the canonical Wnt/β-catenin pathway via the miR-137-3p/Sox9 axis, which leads to fusion failure of the URS and cloacal membrane, and eventually contributed to ARMs. Our achievements might boost the comprehension of ARM pathogenesis and could provide a novel candidate target for the development of therapies for ARMs to complement surgical treatment.

Embryology and anatomy of anorectal malformations

The etiology of anorectal malformations (ARM) is complicated because of the spectrum of anomalies seen clinically, many of which are isolated and seemingly unique. Recent studies suggest that ARMs result from abnormal cloacal membrane (CM) development that contributes to disrupt normal local muscle and nerve development. If CM maldevelopment is severe, the rectal pouch lies above the pelvic floor, resulting in asymmetric and/or deviated musculature, so a midline incision is likely to cause trauma or be detrimental. Autonomic nerve plexuses can be associated with a fistula tract in ARMs and are also at risk for damage during surgery and contribute to genitourinary complications. Understanding the anatomy and development of the perineum is crucial for treating the broad spectrum of anomalies associated with ARMs and may assist in predicting/managing other related morbidity.

Wnt5a plays a critical role in anal opening in mice at an early stage of embryonic development

PURPOSE

Anorectal malformations are associated with other organ malformations. Proximodistal elongation of the cloacal plate and anal opening at its distal end are essential for anal development. However, the anal developmental stage in which Wnt5a is directly involved remains unelucidated. Here, we attempted to identify this developmental stage; since Wnt5a is expressed in the mesoderm, and the striated muscle complex (SMC) in mice develops from the mesoderm, we also examined Wnt5a contribution to SMC development.

METHODS

We established conditional knockout (CKO) mice in which Wnt5a could be knocked out using an appropriate tamoxifen dose. We evaluated the macroscopic appearance and histopathological features of Wnt5aCKO and wild-type mouse embryos.

RESULTS

Wnt5aCKO mice showed phenotypes typical of Wnt5a constitutional knockout mice when Wnt5a was knocked out at E8-E11. Furthermore, the anus failed to open when Wnt5a was knocked out at E8 but opened when it was knocked out at E9 or thereafter. The caudal end of the SMC was dysplastic in Wnt5aCKO mice induced at E8, but was unaffected when mice were induced at E9 or thereafter.

CONCLUSION

We suggest a critical role for Wnt5a in anal opening and SMC formation at a very early stage of embryonic development.

Association between maternal exposure to PM10 and risk of anorectal atresia/stenosis in offspring: a population-based case-control study in Liaoning Province, China

The potential association between maternal exposure to PM₁₀ ranging from 3 months prior to conception to the end of the early trimester and the risk of anorectal atresia/stenosis in offspring has not been established. Thus, we determined the association between maternal exposure to PM₁₀ and risk of anorectal atresia/stenosis in offspring in this study. We recruited 713 patients including 480 male and 233 female with anorectal atresia/stenosis and 7950 randomly selected healthy offspring from the Maternal and Child Health Certificate Registry of Liaoning Province and delivered between 1 January 2010 and 31 December 2015. Monthly PM₁₀ concentrations were retrieved from the Environment Protection Bureau of each city in Liaoning Province. We established a multivariable logistic regression model to calculate the adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Maternal exposure to PM₁₀ was associated with an increased risk for anorectal atresia/stenosis in offspring during the 3 months prior to conception (per 10 μg/m³ increment: OR = 1.15, 95% CI = 1.03-1.20; per SD [27 μg/m³] increment: OR = 1.33, 95% CI = 1.09-1.63) and the first trimester (per 10 μg/m³ increment: OR = 1.08, 95% CI = 1.00-1.17; per SD [28 μg/m³] increment: OR = 1.26, 95% CI = 1.01-1.57). Evaluation of the association with a shorter exposure window (1 month) revealed a positive association between anorectal atresia/stenosis and PM₁₀ from the 3rd month prior to pregnancy to each month of the 1st trimester. Maternal exposure to PM₁₀ 3 months prior to conception and during the 1st trimester was associated with an increased risk of anorectal atresia/stenosis in the offspring. Future perspective cohort studies are needed to confirm our findings.

Development of Sacral Ratio Percentile Card for Children: A Preliminary Report

INTRODUCTION

 Sacrospinal anomalies that may accompany anorectal malformations may cause fecal and urinary incontinence despite proper anomaly treatment. The sacral ratio has been suggested in the determination of both the prognosis in terms of incontinence and the need for further examination for sacrospinal anomalies. The normal and clinically decisive values of sacral ratio are given differently in publications. We aimed to determine the distribution of the sacral ratio in children under 12 months and to develop the sacral ratio percentile card that will enable one to give an age-independent parametric result in clinical evaluations.

MATERIALS AND METHODS

 The files of patients under 1 year of age who had anteroposterior direct radiography including pelvis were reviewed retrospectively. Sacral ratio was studied for 360 patients, 30 patients per month. Percentile card was developed with LMS software and reference values were used as 1, 2, 3, 4, and 10%.

RESULTS

 The lowest sacral ratio value was 0.514 and the highest value was 0.936. There was no statistical difference between the mean sacral ratio of the cases when they were classified on a monthly basis (p = 0.191). Low percentile values were found slightly different at first 4 months of age.

CONCLUSION

 Although the mean of sacral ratio does not change significantly during the first year of life, values that are considered pathological for patients are within different percentile limits depending on age. Instead of using sacral ratio with some clinically decisive values, we think that parametric evaluation with the help of the percentile card will increase its clinical value.

Considering the value of online support groups for colorectal conditions: perspectives from caregivers and adult patients

PURPOSE

To evaluate the benefits of participating in an online support group for caregivers of children with a colorectal condition or adult patients with a similar condition.

METHODS

An electronic survey was administered to members of an international online support group (18 items for caregivers; 15 for patients). Items included demographics, medical diagnosis, potential benefits, and overall experiences in the group. Quantitative results were summarized as descriptive trends, while qualitative responses were summarized thematically.

RESULTS

Respondents (102 caregivers, 6 patients) were primarily female, 35-44 years old, Caucasian, and resided in the United States. Most respondents learned about the support group from medical providers or online search. Cited benefits included learning information, gaining support, forming connections through shared experience, and utilizing a unique resource. Being a member of the group was helpful to respondents, improved their mental health and access to health information, and they would recommend the group to others.

CONCLUSION

Participation in online support groups offers educational and emotional benefits to patients/caregivers which complements the medical support from their colorectal teams. Thus, colorectal providers need to be aware of the availability and potential benefits of these groups, and encourage their patients/caregivers to be actively involved.

Investigation of the risk factors of anorectal malformations

PURPOSE

To investigate the factors that influence the occurrence of anorectal malformations (ARMs).

METHODS

From December 2018 to December 2019, 136 children treated for ARMs at the Children's Hospital of Chongqing Medical University were included in the case group. The control group consisted of children with intussusception or perianal abscesses. A uniform questionnaire was filled by the parents of the enrolled children.

RESULTS

The birth weight of the cases was significantly lower than that of the controls (p < .01), and children with ARMs were more likely to be complicated with single umbilical artery (SUA) (p < .001). Maternal upper respiratory tract infection (adjusted odds ratio [OR_adj ], 2.44; 95% confidence interval [CI], 1.29-4.63) and urogenital infection (OR_adj , 2.67; 95% CI 1.11-6.38) during the first trimester of pregnancy, anemia during pregnancy (OR_adj , 5.69; 95% CI, 1.01-32.07), and exposure to hazardous substances 6 months before pregnancy and during the first trimester of pregnancy (OR_adj , 13.82; 95% CI, 3.86-49.35) are associated with increased risk of ARMs. Folic acid supplements (OR_adj , 0.31; 95% CI, 0.14-0.65) and multivitamin (OR_adj , 0.34; 95% CI, 0.15-0.79) had a protective effect on ARMs. Paternal drug use (OR_adj , 9.17; 95% CI, 2.19-38.49) 6 months before their wives' conception increased the risk of ARMs.

CONCLUSION

Maternal infection, anemia during pregnancy, and maternal hazardous substances exposure are possible risk factors for ARMs. Folic acid supplements and multivitamin can reduce the occurrence of ARMs. Meanwhile, paternal drug use may also be a risk factor for ARMs.

RNA-Seq Profiling of Circular RNAs During Development of Hindgut in Rat Embryos With Ethylenethiourea-Induced Anorectal Malformations

Anorectal malformations (ARMs) are among the most common congenital terminal digestive tract malformations. Circular RNAs (circRNAs), a novel type of endogenous non-coding RNAs, play roles in the development of the digestive system; however, their contributions to the pathogenesis of ARMs are not well-established. In this study, we explored the mechanism underlying ethylenethiourea (ETU)-induced ARMs by profiling circRNA expression via RNA-seq and constructing a regulatory circRNA-miRNA-mRNA network. Nine pregnant rats were gavage-fed a single dose of 125 mg/kg 1% ETU (ARM group) on gestational day 10 (GD10), and another 9 pregnant rats received a similar dose of saline (normal group) as a control. Embryos were obtained by cesarean section on the key time-points of anorectal development (GD14, GD15, and GD16). Hindgut samples isolated from the fetuses were evaluated by high-throughput sequencing and differentially expressed circRNAs were validated by reverse transcription-quantitative polymerase chain reaction, agarose gel electrophoresis, and Sanger cloning and sequencing. A total of 18295 circRNAs were identified in the normal and ARM groups. Based on the 425 differentially expressed circRNAs (|Fc| > 2, p < 0.05), circRNA-miRNA and miRNA-mRNA pairs were predicted using miREAP, miRanda, and TargetScan. A total of 55 circRNAs (14 up- and 41 downregulated in the ARM group compared to the normal group) were predicted to bind to 195 miRNAs and 947 mRNAs. Competing endogenous RNA networks and a Kyoto Encyclopedia of Genes and Genomes analysis revealed that novel_circ_001042 had the greatest connectivity and was closely related to ARM-associated signaling pathways, such as the Wingless Type MMTV integration site family, mitogen-activated protein kinase, and transforming growth factor-β pathways. These results provide original insight into the roles of circRNAs in ARMs and provide a valuable resource for further analyses of molecular mechanisms and signaling networks.

Upregulation of PPPDE1 contributes to anorectal malformations via the mitochondrial apoptosis pathway during hindgut development in rats

Congenital anorectal malformations (ARMs) are among the most prominent deformities of the gastrointestinal tract; however, their precise aetiology remains obscure. Immunohistochemistry demonstrated that, in the ARM group, the PPPDE1-positive cells were widely distributed in the hindgut epithelial tissue from GD13 to GD16. Immunofluorescence revealed that most TUNEL-, Bax-, and Cytochrome C (Cyt C)-positive cells overlapped with PPPDE1-positive cells in the urorectal septum (URS). Western blotting and quantitative real-time RT-PCR revealed that PPPDE1 levels were significantly higher in the ARM group from GD13 to GD14 (p < 0.05). IEC-6 cells were transfected with PPPDE1 overexpression plasmid/NC (negative control) or si-PPPDE1/si-NC. Flow cytometry analysis and CCK-8 assay (used to detect apoptosis and proliferation, respectively), as well as western blotting, showed that the levels of PPPDE1 were positively correlated with the pro-apoptotic molecules Bax and Cyt C. Accordingly, aberrantly high expression of PPPDE1 caused a spatiotemporal imbalance in foetal rats with ARMs during hindgut development. Therefore, the upregulation of PPPDE1 may promote epithelial apoptosis and reduce proliferation in the hindgut via the mitochondrial apoptotic pathway. This could affect the fusion of the URS and cloacal membrane, ultimately inhibiting the hindgut development and resulting in ARMs.

Risk factors for anorectal and associated malformations in German children: A 10-year analysis

BACKGROUND

Incidences of anorectal malformations (ARM) occur in 1 of 2000-5000 live births and up to 64% have associated malformations (ARMa). The aim of the study was to evaluate possible prenatal risk factors for ARM in a tertiary hospital.

METHODS

A case-control design was used to compare risk factors in ARM (n = 44) to a control group (CG; n = 26). We used modified prenatal questionnaires, analyzed mothers' prenatal records and participants completed a structured interview. Endpoints were medical history, drug consumption, occupational risk factors, and time point of diagnosis, associated malformations and sensitivity of radiological imaging.

RESULTS

Our results showed that ARM couples had a significantly higher age difference (p = 0.028) compared to CG. ARM mothers had more abnormalities during pregnancy (p = 0.002), more positive vaginal smears of group B streptococci (p = 0.024), urogenital infections (p = 0.005), gestosis (p = 0.03), emesis (p = 0.025) and higher numbers of chronic diseases (p = 0.018). ARM mothers took less medication during pregnancy (p = 0.013) than CG mothers including folic acid (p = 0.041); their intake of iodine tablets was significantly higher (p = 0.035) and they continued smoking for longer (p = 0.036) than CG mothers, and they had more stillbirths (p = 0.035). In using illegal drug and alcohol use, the groups did not show significant differences. ARMa was present in 68.1% (n = 30), of which 45.5% were of urogenital origin (n = 20). ARM diagnosis was made on the first day of life in 72.7% (n = 32), while diagnosis was delayed in 12 patients (27.3%).

CONCLUSION

A combination of different risk factors seem to be associated with the development of ARM, which takes place at an early stage (<7th week) of pregnancy. Therefore, risk factors influencing fetal development must be critically considered. We advocate an interdisciplinary assessment in unclear clinical findings on first day of life to optimize the therapy and positively influence the outcome.

Maternal intake of one-carbon metabolism-related B vitamins and anorectal malformations in the Japan Environment and Children's Study

The occurrence of anorectal malformations (ARM) is thought to be reduced with sufficient folate intake. However, there is no apparent evidence. We focused on enzyme cofactors for one-carbon metabolism, including folate (vitamin B9), vitamin B6 and vitamin B12, and explored the association between maternal combined intake of these B vitamins and the risk of ARM. Using baseline data from a Japanese nationwide birth cohort study between 2011 and 2014, we analysed data of 89 235 women (mean age at delivery = 31·2 years) who delivered singleton live births without chromosomal anomalies. Information on dietary intake was obtained via a FFQ focused on early pregnancy and used to estimate B vitamin intake. We also collected information on the frequency of folic acid supplement use. ARM occurrence was ascertained from medical records. We identified forty-three cases of ARM diagnosed up to the first month after birth (4·8 per 10 000 live births). In terms of individual intake of the respective B vitamins, high vitamin B6 intake was non-significantly associated with reduced odds of ARM. Compared with women in the low combined B vitamin intake group, the OR of having an infant with ARM was 0·4 (95 % CI 0·2, 1·0) in the high intake group (folate ≥400 μg/d, and upper half of vitamin B6 and/or vitamin B12). In conclusion, our cohort analysis suggested an inverse association between the combined intake of one-carbon metabolism-related B vitamins in early pregnancy and ARM occurrence.

Folic acid rescues all-trans retinoic acid-induced anorectal malformations in rats

BACKGROUND

To investigate whether folic acid (FA) can rescue anorectal malformations (ARMs) induced by all-trans retinoic acid (ATRA) in rats.

METHODS

Pregnant Sprague-Dawley rats were randomly divided into three groups. In the model group, rats were administered ATRA (110 mg/kg) by gavage on the 10th day of gestation (E10.5). Rats in the rescue group were administered FA (40 mg/kg) by gavage 0.5 and 12 hr after treatment with ATRA. All fetuses were harvested on E20.5 using cesarean section and examined for ARMs. We recorded the weight, body length, tail length, and associated malformations of all the embryos. Hematoxylin and eosin staining was used to analyze the histopathology of the fetuses.

RESULTS

Control rats did not show any abnormalities. ARMs, tail deformities (less than half of normal length), and neural tube defects were found in 97.98% (97/99), 92.93% (92/99), and 32.32% (32/99) of the rats in the model group, respectively. The incidence of ARMs and tail deformities were 48.57% (51/105) and 35.24% (37/105), respectively, in the rescue rats; no neural tube defects were observed in these rats. The weight, body length, and tail length of the fetal rats in the rescue group were more than those in the model group, but less than those in the control group.

CONCLUSION

Taken together, FA rescued ARMs induced by ATRA in rats. Thus, FA may reduce the incidence of associated malformations and improve the growth and development of fetal rats.

Comparison of Maternal Histories and Exposures in Children With Isolated Anorectal Malformation Versus Anorectal Malformation With Genitourinary Anomalies

Introduction

To our knowledge, there are no studies to date that have compared patients with isolated anorectal malformation (ARM) to patients with ARM and an associated genitourinary (GU) malformation despite a possible etiological difference between these two entities. We examined the differences in maternal and prenatal exposures and comorbidities between patients with isolated ARM and patients with ARM and associated GU malformations.

Materials and methods

A retrospective cohort study of children with ARM, enrolled in the Pediatric Colorectal and Pelvic Learning Consortium (PCPLC) between February 2017 and October 2019, was performed comparing those with isolated ARM to those with ARM and associated GU anomalies (GU +/- additional anomalies) as well as to those with ARM and a GU anomaly with no anomaly of any other system (GU-only). We compared the prevalence of prematurity, family history of colorectal disorders, as well as maternal and prenatal comorbidities and exposures between these two cohorts and the isolated ARM cohort.

Results

A total of 505 patients (117 with isolated ARM and 388 with ARM and associated GU anomalies) were enrolled. Of the 388 patients with ARM and associated GU anomalies, 48 had an ARM with a GU anomaly without an anomaly in any other system. There was an increased prevalence of premature births in the GU +/- additional anomalies cohort compared to the isolated ARM cohort (27 vs 14%, p=0.003). This difference was not seen in the GU-only cohort. There was no difference between the cohorts regarding prevalence of family history of ARM or maternal and prenatal comorbidities or exposures.

Conclusions

Patients with an ARM and an associated GU anomaly with or without other congenital anomalies are more likely to be born prematurely compared to patients with an isolated ARM. Parents of these children should be counseled on this increased risk.

Prevalence and survival of patients with anorectal malformations: A population-based study

BACKGROUND

Anorectal malformations (ARMs) are the most frequent congenital intestinal anomalies. The aim of this study was to describe the epidemiology of anorectal defects between 1981 and 2014 and to evaluate patients' survival.

METHODS

A population-based study using data collected by an Italian, regional registry of birth defects and by the local Pediatric Surgery Units.

RESULTS

A total of 428 individuals with ARM were identified, with an overall prevalence of 3.09 per 10,000 births. Characteristics associated with decreased survival were low birth weight (<2500 g) (HR 6.4; 95% CI, 2.3-17.9), the presence of two or more additional major defects (HR 7.9; 95% CI, 2.2-27.8), and birth before year 2000 (HR 4.7; 95% CI, 1.8-11.8). The 10-year survival probability was 100% for individuals with isolated ARM, regardless of their birth weight. Survival of patients with non-isolated ARM varied according to their year of birth and birth weight: 73.3% (≥2500 g) and 23.8% (<2500 g) in children born before 2000; 97.9% (≥2500 g) and 68.8% (<2500 g) in children born after year 2000.

CONCLUSIONS

This study found a significant improvement in the survival of individuals with anorectal malformations over the past decades and identified the strongest predictors of mortality.

LEVEL OF EVIDENCE (PROGNOSIS STUDY)

Level II.

Malformations, choristomas, and hamartomas of the gastrointestinal tract and pancreas

Congenital and hamartomatous lesions of the gastrointestinal tract cause diagnostic challenges for surgical pathologists. Many of these are merely histologic curiosities, whereas others have substantial clinical implications because they herald cancer syndromes or associated anomalies. Although a comprehensive discussion of all developmental abnormalities that can occur in the gastrointestinal tract is beyond the scope of a single manuscript, some entities are more likely to be encountered by surgical pathologists, have important clinical consequences, or pose diagnostic difficulties. The purpose of this review is to discuss the more common malformations and choristomas, as well as hamartomatous lesions that may be clinically important due to their risk for cancer development, frequent associations with heritable cancer syndromes and other anomalies, or potential to simulate other entities.

Maternal risk factors and perinatal characteristics of anorectal malformations

PURPOSE

The aim of this study was to assess maternal risk factors and perinatal characteristics of patients with anorectal malformations (ARM) in Sweden.

METHODS

Population-based case-control study including all patients with ARM born in Sweden 1973-2014. Patients were identified from the Swedish National Patient Register, and data on possible maternal risk factors and perinatal characteristics were obtained from the Swedish Medical Birth Register. The association between study variables and ARM was analyzed using conditional logistic regression.

RESULTS

1167 patients and 5835 controls were analyzed. Patients with ARM were more often prematurely born (<35 weeks: OR 4.81 95% CI 3.42-6.75, 35-36 weeks OR 2.96 95% CI 2.13-4.11) or small for gestational age (SGA) (OR 3.82 95% CI 2.66-5.50). Maternal BMI ≥30 was associated with an increased risk for ARM (OR 1.42; 95% CI 1.08-1.86). Maternal smoking ≥10 cigarettes daily was associated with ARM only in patients without associated malformations (OR 1.67 95% CI 1.08-2.58).

CONCLUSIONS

Maternal obesity is a possible risk factor for ARM. Prematurity and SGA was more common among ARM patients. Maternal smoking may be a risk factor of ARM in patients without associated malformations.

LEVEL OF EVIDENCE

III.

Fish consumption in early pregnancy and congenital gastrointestinal tract atresia in the Japan Environment and Children's Study

Current evidence suggests that the aetiology of congenital gastrointestinal (GI) tract atresia is multifactorial, and not based solely on genetic factors. However, there are no established modifiable risk factors for congenital GI tract atresia. We used data from a Japanese nationwide birth cohort study launched in 2011, and examined whether fish consumption in early pregnancy was associated with congenital GI tract atresia. We analysed data of 89 495 women (mean age at delivery=31·2 years) who delivered singleton live births without chromosomal anomalies. Based on the results of the FFQ, we estimated the daily intake of fish and n-3 PUFA consumption in early pregnancy. We defined a composite outcome (oesophageal atresia, duodenal atresia, jejunoileal atresia and/or anorectal malformation) as congenital GI tract atresia. In this population, median fish intake was 31·9 g/d, and seventy-four cases of congenital GI tract atresia were identified. Fish consumption in early pregnancy was inversely associated with the composite outcome (multivariable-adjusted OR for the high v. low consumption category=0·5, 95 % CI 0·3, 1·0). For all the specific types of atresia, decreased OR were observed in the high consumption category, although not statistically significant. Reduced atresia occurrence was observed even beyond the US Food and Drug Administration's recommended consumption of no more than 340 g/week. Also, n-3 PUFA-rich fish and n-3 PUFA consumptions tended to be inversely associated with atresia. Fish consumption in early pregnancy may be a preventive factor for congenital GI tract atresia.

Integrative analysis of microRNA and mRNA expression profiles in fetal rat model with anorectal malformation

Background

Anorectal malformations (ARMs) are the most common congenital malformation of the gut, and regulated by multiple signal transduction pathways. The microRNA (miRNA) expression profiles and their biologial functions in anorectal malformations (ARMs) remain unclear. The aim of our study was to evaluate miRNA and mRNA expression profiles in the ARM rats.

Methods and Materials

ARM was induced with ethylenethiourea (ETU) on gestational day 10. Cesarean deliveries were performed to harvest the embryos on gestional day 20. For the extraction of total RNA, 1 cm terminal hindgut samples were obtained from three fetal rats that had similar weights. The microarrays and quantitative RT-PCR analysis were conducted to evaluate the miRNA and mRNA expression profiles in normal fetal rats (n = 3) and ARM fetal rats (n = 3).

Results

In total, 33 miRNAs and 772 mRNAs were significantly and differentially expressed in terminal hindgut tissues of ARM group versus control group. Functional annotation was performed to understand the functions and pathways of differentially expressed mRNAs. Also, we constructed a miRNA-target gene regulatory network including 25 differentially expressed miRNAs and 76 mRNAs. Furthermore, the credibility of the microarray-based results were validated by using qRT-PCR.

Conclusion

The miRNA and mRNA expression in terminal hindgut tissue of ARM fetal rats might provide a basis for further research on the pathogenesis of ARMs.

MSX2 and BCL2 expressions in the development of anorectal malformations in ethylenethiourea-induced rat embryos

BACKGROUND

This study aimed to determine Msh homeobox 2 (MSX2) and B cell lymphoma-2 (BCL2) expression patterns during anorectal development in anorectal malformations (ARM) and normal rat embryos, with the goals of determining the role of MSX2 and BCL2 in ARM pathogenesis.

METHODS

ARM was induced in rat embryos with ethylenethiourea administered to dams on gestational day 10 (GD10). Embryos were harvested by cesarean deliveries from GD14 to GD16. MSX2 and BCL2 expression was evaluated via immunohistochemical staining, immunofluorescence, western blotting and quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

Immunohistochemical staining of ARM embryos revealed that MSX2 was mainly expressed in the epithelium of the hindgut and urorectal septum (URS) on GD14. On GD15 and GD16, MSX2-immunolabeled cells were noted in the epithelium of the rectum, fistula and URS. However, in normal embryos, faint immunopositivity for MSX2 was demonstrated in the epithelium of the rectum and URS from GD14 to GD16. As for BCL2, in normal embryos, BCL2-immunopositive cells were extensively expressed in the epithelium of the hindgut and URS on GD14 and GD15. In ARM embryos, weak immunopositivity for BCL2 was detected in the epithelium of hindgut and URS on GD14 and GD15. Immunofluorescence revealed that MSX2 and BCL2 colocalized in the hindgut. In ARM embryos, we observed more MSX2-positive than BCL2-positive cells on GD14; the normal embryos had the opposite pattern. Analyses by western blot and qRT-PCR showed that MSX2 protein and mRNA expression was significantly increased in ARM embryos compared with the normal embryos on GD15 and GD16 (p < 0.05). However, BCL2 protein and mRNA expression was significantly decreased in ARM embryos compared with the normal embryos on GD14 (p < 0.05). The MSX2/BCL2 ratio of protein and mRNA expression level in the ARM group was the highest on GD15.

CONCLUSION

These results indicate that upregulation of MSX2 and downregulation of BCL2 during cloacal development into the rectum and urethra might be related to the ARM development, and MSX2 promoted apoptosis through reduction of BCL2 expression during the development of anorectal development in ARM.

Clinical characteristics, prognosis, and its risk factors of anorectal malformations: a retrospective study of 332 cases in Anhui Province of China

Objective: To analyze the clinical characteristics and prognosis of anorectal malformations (ARMs) and explore the influencing factors of postoperative anal function in Anhui Province of China.Methods: We performed a retrospective study of ARM patients diagnosed from 2013 to 2016 at Anhui Provincial Children's Hospital. A total of 332 infants with ARM were enrolled in the survey. Demographic characteristic and clinical data were collected. Follow-up study was required to evaluate anal function after the operation and Logistic regression analysis was used for analyzing the influencing factors of prognosis.Results: A total of 253 males and 79 females were studied, with a ratio of 3.2:1. Abdominal distention was the most common presenting symptom, followed by vomiting. Of the cases, 53.0% (176/332) combined with other congenital malformations. The incidence of other malformations in intermediate and high ARM group was significantly higher than that in the low ARM group. Of the cases, 280 underwent anoplasty. 188, 73, 19 cases were treated with one-stage perineal anoplasty, posterior sagittal anorectoplasty, laparoscopically assisted anorectal pull-through, respectively. The result of follow-up study showed that the excellent and good rate of postoperative anal function was up to 83.3%. Type of ARM, combined with other malformations and the times of anoplasty were related to the anal function postoperatively.Conclusions: ARM occurs mainly in male infants. The incidence of associated abnormalities in ARM patients was high. Intermediate- and high-type, combined with other malformations and more times of anoplasty increased the risk of anal dysfunction postoperatively. Multicenter, prospective randomized-controlled studies were needed to clarify the curative effect of different surgical approaches.

Integrating lncRNAs and mRNAs expression profiles in terminal hindgut of fetal rats with anorectal malformations

BACKGROUND

The detailed embryonic etiology and pathogenesis of anorectal malformations (ARMs) remains unclear. Recent studies have shown that gene expression abnormalities were the key factors that result in ARMs. Long non-coding RNAs (lncRNAs) were reported as the 'transcriptional noise' within the genome. The expression profiles of lncRNA and mRNA remain less characterized in the pathogenesis of ARMs. Furthermore, the function of lncRNAs in the regulation of this process has not been investigated so far. Therefore, this current study was aimed to integrate lncRNA and mRNA expression profiles in terminal hindgut of ethylenethiourea (ETU)-induced ARM rats using Agilents lncRNA and mRNA co-expression microarrays.

METHODS

ARM model was induced with ethylenethiourea (ETU) on gestational day 10. Cesarean deliveries were conducted to collect the embryos on gestational day 20. For the extraction of total RNA, 1-cm terminal hindgut tissues were collected from three fetal rats with similair weights. The microarrays and quantitative RT-PCR analysis were conducted to evaluate the lncRNA and mRNA expression profiles in normal fetal rats and ARM fetal rats.

RESULTS

Compared with control group, 164 lncRNAs were observed to be aberrantly expressed (FC ≥ 2; P < 0.05) in ARM group, including 36 upregulated and 128 downregulated, while 772 mRNAs were observed to be aberrantly expressed (FC ≥ 2; P < 0.05) in the terminal hindgut, including 350 up-regulated and 422 down-regulated. The differential expression profiles between the ARM and the control group were used for gene ontology (GO) and pathway analysis. A subset of those RNAs was identified to be closely related to the development process of ARMs. The four RNAs that were differentially expressed between the two groups were selected for qPCR validation, and the results were in line with the microarray data. In addition, the lncRNAs and mRNA co-expression network was established according to the correlation analysis. We predicted the functions of transregulatory lncRNAs by the TFs (transcription factors) which might modulate their expression. In the core network of lncRNA-TF pairs, the lncRNAs can be classified into 5 categories of pathways governed by Jun, c-Myc, Usf1, Alf2, and Stat3.

CONCLUSION

From the above results, it can be suggested that these aberrant lncRNAs might participate in the pathogenesis of ARM, and our present work may provide new research directions for future studies of ARMs.

Microarray analysis of miRNAs during hindgut development in rat embryos with ethylenethiourea‑induced anorectal malformations

Anorectal malformations (ARMs) are one of the most common congenital malformations of the digestive tract; however, the pathogenesis of this disease remains to be fully elucidated. MicroRNAs (miRNAs) are important in gastrointestinal development and may be involved in the pathogenesis of ARMs. The present study aimed to profile miRNAs and examine their potential functions in rats with ethylenethiourea (ETU)-induced ARMs. Pregnant Wistar rats (n=36) were divided randomly into ETU-treated and control groups. The rats in the ETU-treated group were gavage-fed 1% ETU (125 mg/kg) on gestational day 10 (GD10), whereas the control group rats received a corresponding dose of saline. Embryos were harvested by cesarean section on GD14, GD15 and GD16. Hindgut tissue was isolated from the fetuses for RNA extraction and microarray analysis, followed by bioinformatics analysis and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) validation. Overall, 38 miRNAs were differentially expressed (all upregulated) on GD14, 49 (32 upregulated and 17 downregulated) on GD15, and 42 (all upregulated) on GD16 in the ARM group compared with the normal group. The top 18 miRNAs with |log₂(fold change)| >4.25 were selected for further bioinformatics analysis. Among these miRNAs, five were differentially expressed at two time-points and were involved in ARM-associated signaling pathways. The RT-qPCR analysis revealed that three miRNA (miR), miR-125b-2-3p, miR-92a-2-5p and miR-99a-5p, were significantly differentially expressed in rats with ARMs compared with the normal group. In conclusion, the results suggested that the differential expression of miR-125b-2-3p, miR-92a-2-5p and miR-99a-5p during key time-points of anorectal formation in rats may have functions in the pathogenesis of ARM.

FOXD3/FOXD4 is required for the development of hindgut in the rat model of anorectal malformation

Congenital anorectal malformation is the most common digestive tract malformation in newborns. It has been reported that FOXD3/FOXD4, a forkhead transcription factor, regulates the generation, migration, and differentiation of neural crest cells. However, whether FOXD3/FOXD4 takes part in anorectal malformation remains unclear. In the present study, we used ethylene thiourea to induce the animal models of anorectal malformation in rat embryos and to interrogate the role of FOXD3/FOXD4 in anorectal malformation pathogenesis. Hindgut samples of the animal models were collected at E15, E17, E19, and E21 days of age. The expression of FOXD3/FOXD4 was detected by immunohistochemistry, western blot, and quantitative real-time fluorescence PCR. By immunohistochemical staining, FOXD3/FOXD4 was observed in epithelial cells of the rectum and the anus both in normal and rat embryos with anorectal malformation. Expression level analysis by western blot indicated that FOXD3/FOXD4 expression increased in ethylene thiourea-induced anorectal malformation groups. mRNA expression as determined by quantitative real-time fluorescence PCR analysis was consistent with the western blot results. Tentative conclusions were drawn that FOXD3/FOXD4 is expressed in the hindgut in rat embryos and is upregulated in anorectal malformation. FOXD3/FOXD4 is required for the development of the hindgut, and its aberrant expression may be an important factor leading to the incidence of anorectal malformation. Impact statement Congenital anorectal malformation (ARM) is the most common digestive tract malformation in newborns. The pathophysiological ground remains unclear. In this study, we used animal models of ARM for the first time to interrogate the role of FOXD3/FOXD4 in ARM pathogenesis. The animal models of ARM were successfully induced by ethylene thiourea (ETU) in rat embryos providing a strong basis for pathogenesis study of this disease. Expression analysis of FOXD3/FOXD4 was carried out in these models, and the results shape a deeper understanding of FOXD3/FOXD4 being required for the normal development of the hindgut. The aberrant expression of FOXD3/FOXD4 may be an important factor leading to ARM incidence.

A review of genetic factors contributing to the etiopathogenesis of anorectal malformations

BACKGROUND

Anorectal malformation (ARM) is a common congenital anomaly with a wide clinical spectrum. Recently, many genetic and molecular studies have been conducted worldwide highlighting the contribution of genetic factors in its etiology. We summarize the current literature on such genetic factors.

MATERIALS AND METHODS

Literature search was done using different combinations of terms related to genetics in anorectal malformations. From 2012 to June 2017, articles published in the English literature and studies conducted on human population were included.

OBSERVATIONS AND RESULTS

A paradigm shift was observed from the earlier studies concentrating on genetic aberrations in specific pathways to genome wide arrays exploring single nucleotide polymorphisms (SNPs) and copy number variations (CNVs) in ARM patients. Rare CNVs (including 79 genes) and SNPs have been found to genetically contribute to ARM. Out of disrupted 79 genes one such putative gene is DKK4. Down regulation of CDX-1 gene has also been implicated in isolated ARM patients. In syndromic ARM de novo microdeletion at 17q12 and a few others have been identified.

CONCLUSION

Major genetic aberrations proposed in the pathogenesis of ARM affect members of the Wnt, Hox (homebox) genes, Sonic hedgehog (Shh) and Gli2, Bmp4, Fgf and CDX1 signalling pathways; probable targets of future molecular gene therapy.

Spatiotemporal expression of proprotein convertase subtilisin/kexin type 5 in the development of anorectal malformations in fetal rats

This study examined the expression patterns of proprotein convertase subtilisin/kexin type 5 (Pcsk5) during anorectal development in normal and anorectal malformations (ARM) rat embryos, determine the possible role of Pcsk5 in the pathogenesis of ARM. An ARM rat model was developed by the administration of ethylenethiourea gestational day 10 (GD10). Embryos were harvested by surgical excision from GD13 to GD16, and the spatiotemporal expression of Pcsk5 was evaluated, using immunohistochemistry staining, Western blotting and real time RT-PCR. Immunohistochemistry staining in normal embryos revealed that Pcsk5 was abundantly expressed on the epithelium of the cloaca (CL) on GD13. On GD14 and GD15, positive cells were noted on the urorectal septum and the thin anal membrane. However, the epithelium of the CL of ARM embryos only faintly expressed Pcsk5 from GD13 to GD15. Western blotting and real time RT-PCR showed time-dependent increase of Pcsk5 expression in the developing hindgut. Pcsk5 expression levels were lower in the ARM group from GD14 to GD16 (p ≤ 0.05). These results indicate that downregulation of Pcsk5 during cloaca development into the rectum and urethra might be related to the formation of ARMs.

Differential miRNA expression analysis during late stage terminal hindgut development in fetal rats

BACKGROUND

Terminal hindgut deformity is the leading digestive tract malformation, however, the etiology and pathogenesis remained unknown. To date, gene expression abnormalities were considered the primary cause of these diseases. miRNAs have been found to play an important role in regulating the expression of genes.

METHODS

A total of 24 pregnant rats were randomly divided into two groups. The experimental group (n=12) received 1% ethylenethiourea (125mg/kg) by gavage on gestational day 11, while the control group (n=12) received the same volume of distilled water. From each group, fetal rats were obtained by cesarean section on gestational day 16. For the extraction of total RNA, 1 cm rectum samples were obtained from four fetal rats that had similar weights. Chip hybridization was conducted after poly(A) and biotin were added to the RNA samples, and this was followed by washing, dyeing, and scanning of the chip. Differences identified in the miRNA expression profiles and the target gene analysis results were further analyzed to identify potential regulators of terminal hindgut development.

RESULTS

Compared with the control group, 111 miRNAs expressed in the terminal hindgut of the experimental group were up-regulated on gestational day 16, while 117 miRNAs were down-regulated. The ten miRNAs with the greatest differential expression profiles between the experimental and control samples were selected for target gene prediction, pathway analysis, and gene ontology analysis. A subset of these miRNAs was found to be closely related to rat fetus terminal hindgut growth and development. In addition, target gene analysis showed that miR-193 may have an important role in regulating a key gene in anorectal development, Hoxd13. This role was confirmed in a dual luciferase reporter assay when miR-193 was able to inhibit expression of a reporter gene under the control of the 3' untranslated region of the Hoxd13 gene in the human embryonic kidney cell line, 293T. Real-time PCR and Western blotting experiments further showed that the expression of Hoxd13 was significantly lower when miR-193 was highly expressed in rat intestinal epithelial cells. The differences in both sets of experiments were statistically significant compared with the negative control group (P<0.05).

CONCLUSION

These data support an important regulatory role for miRNAs in the expression of target genes during terminal hindgut development in fetal rats. In particular, miR-193-mediated inhibition of Hoxd13 was found to be significant in rat intestinal epithelial cells.

Delayed diagnosis of 22q11 deletion syndrome due to late onset hypocalcemia in a 11-year-old girl with imperforated anus

Neonatal hypocalcemia and congenital heart defects has been known as the first clinical manifestation of the chromosome 22q11.2 deletion syndrome (22q11DS). However, because of its wide clinical spectrum, diagnosis of 22q11DS can be delayed in children without classic symptoms. We report the case of a girl with the history of imperforate anus but without neonatal hypocalcemia or major cardiac anomaly, who was diagnosed for 22q11DS at the age of 11 after the onset of overt hypocalcemia. She was born uneventfully from phenotypically normal Korean parents. Imperforate anus and partial cleft palate were found at birth, which were surgically repaired thereafter. There was no history of neonatal hypocalcemia, and karyotyping by GTG banding was normal. At the age of 11, hypocalcemia (serum calcium, 5.0 mg/dL) and decreased parathyroid hormone level (10.8 pg/mL) was noted when she visited our Emergency Department for fever and vomiting. The 22q11DS was suspected because of her mild mental retardation and velopharyngeal insufficiency, and a microdeletion on chromosome 22q11.2 was confirmed by fluorescence in situ hybridization. The 22q11DS should be considered in the differential diagnosis of hypocalcemia at any age because of its wide clinical spectrum.

Congenital Malformations in River Buffalo (Bubalus bubalis)

Simple Summary

Congenital malformations (due to genetic causes) represent a hidden danger for animal production, above all when genetic selection is undertaken for production improvements. These malformations are responsible for economic losses either because they reduce the productivity of the farm, or because their spread in the population would decrease the total productivity of that species/breed. River buffalo is a species of increasing interest all over the world for its production abilities, as proved by the buffalo genome project and the genetic selection plans that are currently performed in different countries. The aim of this review is to provide a general view of different models of congenital malformations in buffalo and their world distribution. This would be useful either for those who performed buffalo genetic selection or for researchers in genetic diseases, which would be an advantage to their studies with respect to the knowledge of gene mutations and interactions in this species.

Abstract

The world buffalo population is about 168 million, and it is still growing, in India, China, Brazil, and Italy. In these countries, buffalo genetic breeding programs have been performed for many decades. The occurrence of congenital malformations has caused a slowing of the genetic progress and economic loss for the breeders, due to the death of animals, or damage to their reproductive ability or failing of milk production. Moreover, they cause animal welfare reduction because they can imply foetal dystocia and because the affected animals have a reduced fitness with little chances of survival. This review depicts, in the river buffalo (Bubalus bubalis) world population, the present status of the congenital malformations, due to genetic causes, to identify their frequency and distribution in order to develop genetic breeding plans able to improve the productive and reproductive performance, and avoid the spreading of detrimental gene variants. Congenital malformations most frequently reported in literature or signaled by breeders to the Department of Veterinary Medicine and Animal Production of the University Federico II (Naples, Italy) in river buffalo are: musculoskeletal defects (transverse hemimelia, arthrogryposis, umbilical hernia) and disorders of sexual development. In conclusion this review put in evidence that river buffalo have a great variety of malformations due to genetic causes, and TH and omphalocele are the most frequent and that several cases are still not reported, leading to an underestimation of the real weight of genetic diseases in this species.

Spatiotemporal distribution of caudal-type homeobox proteins during development of the hindgut and anorectum in human embryos

Background. The objectives of this study were to determine the spatiotemporal distribution of human caudal-type homeobox proteins CDX1, CDX2 and CDX4 during development of the hindgut and anorectum in the embryo and to explore the possible roles of CDX genes during morphogenesis of the hindgut and anorectum.

Methods. Embryos (89) were cut into sections serially and sagittally. From gestation weeks 4–9, CDX1, CDX2 and CDX4 proteins were detected on the caudal midline by immunohistochemical staining.

Results. During week 4, extensive immunoreactivity of CDX1, CDX2 and CDX4 was detected in the dorsal urorectal septum, urogenital sinus and hindgut. From weeks 5–7, CDX1-, CDX2- and CDX4- positive cells were detected mainly in the mesenchyme of the urorectal septum and hindgut. The levels of CDX2 and CDX4 immunoreactivity were lower compared to CDX1. During weeks 8 and 9, the anorectal epithelium stained positive for CDX1 and CDX4, and the anal epithelium was positive for CDX2.

Conclusions. The CDX proteins are constantly distributed during development of the hindgut and anorectum and exhibit overlapping distribution patterns in the cloaca/hindgut, suggesting they are important in the morphogenesis of the human hindgut and anorectum. CDX genes might be involved in development of the anorectal epithelium after the rectum has separated from the urorectal septum.