Ventral Body Wall Defects Research Articles

Ventral body wall closure: Mechanistic insights from mouse models and translation to human pathology.

The ventral body wall (VBW) that encloses the thoracic and abdominal cavities arises by extensive cell movements and morphogenetic changes during embryonic development. These morphogenetic processes include embryonic folding generating the primary body wall; the initial ventral cover of the embryo, followed by directed mesodermal cell migrations, contributing to the secondary body wall. Clinical anomalies in VBW development affect approximately 1 in 3000 live births. However, the cell interactions and critical cellular behaviors that control VBW development remain little understood. Here, we describe the embryonic origins of the VBW, the cellular and morphogenetic processes, and key genes, that are essential for VBW development. We also provide a clinical overview of VBW anomalies, together with environmental and genetic influences, and discuss the insight gained from over 70 mouse models that exhibit VBW defects, and their relevance, with respect to human pathology. In doing so we propose a phenotypic framework for researchers in the field which takes into account the clinical picture. We also highlight cases where there is a current paucity of mouse models for particular clinical defects and key gaps in knowledge about embryonic VBW development that need to be addressed to further understand mechanisms of human VBW pathologies.

The sequence of acrania–exencephaly–anencephaly (AEAS)- An infrequent case report

Acrania–exencephaly–anencephaly sequence has an incidence of 3.6–5.4 for 10,000 live births and has been reported in literature. Exencephaly, described here is a defect of the neural tube which occurs due to the absence of closure of the neural fold. The main diagnostic ultrasound features include that are characterized by acrania, decreased size of cranial pole in comparison with the chest, irregular cranial surface, with increased amniotic fluid echogenicity due to the damaged brain tissue. Associated with amniotic band syndrome, Pentalogy of Cantrell, limb anomalies and ventral body wall defects. It is incompatible with life. Conducting programs training the budding neuro-sonographers about the knowledge in detection, diagnosis of NTD according to the Carnegie Classification is crucial to look forward in pathogenesis and application in the clinical scenario.

Decoding the dilemma of antenatal ventral body wall defects: A case report and literature review

We are presenting the case of a rare fetal polymalformative syndrome known as the limb body wall complex (LBWC) and its antenatal diagnosis. The level II Anomaly ultrasound of a primigravida female detected exencephaly, thoracoabdominoschisis, club foot, kyphoscoliosis, fetoplacental adherence, and a deficient umbilical cord, classically described in LBWC. It is imperative for radiologists to be familiar with this rare fatal entity of sporadic occurrence and to differentiate it from other non-lethal counterparts for appropriate maternal counseling and timely termination of pregnancy.

Ectopia Cordis with Omphalocele in First Trimester Pregnancy: A Case Report of Incomplete Type of Pentalogy of Cantrell

Ectopia Cordis (EC) is a rare congenital malformation in which the heart is located partially or totally outside the thoracic cavity. It results from the failure of migration of the lateral mesoderm into the midline. The four main ectopic positions are cervical, thoracic, thoracoabdominal and abdominal. EC can manifest as an isolated deformity or as part of a broader group of ventral body wall defects affecting the abdomen, thorax, or both. Pentalogy of Cantrell is a well known association that comprises EC, omphalocele (typically supraumbilical), congenital diaphragmatic hernia, sternal cleft and congenital heart disease. A 27-year-old primigravida came for a routine antenatal ultrasound at 13 weeks of gestation. There was no family history of congenital anomalies, genetic abnormalities, or exposure to teratogenic agents. The ultrasound showed a single foetus corresponding to 13 weeks of gestation with an anterior thoracic defect and an extrathoracic heart, along with partial herniation of the liver near the midline in the epigastric region. These findings were confirmed by foetal Magnetic Resonance Imaging (MRI). An unfavourable prognosis for the foetus was explained to the parents, and medical termination of pregnancy was performed. Therefore, prenatal ultrasonographic diagnosis of EC should be followed by a thorough search for associated defects, as the prognosis may vary.

Y-27632 Impairs Angiogenesis on Extra-Embryonic Vasculature in Post-Gastrulation Chick Embryos

Y-27632 inhibits Rho-associated coiled-coil-containing protein kinase (ROCK) signaling, which is involved in various embryonic developmental processes, including angiogenesis, by controlling actin cytoskeleton assembly and cell contractility. Administration of Y-27632 impairs cytoskeletal arrangements in post-gastrulation chick embryos, leading to ventral body wall defects (VBWDs). Impaired angiogenesis has been hypothesized to contribute to VBWDs. ROCK is essential in transmitting signals downstream of vascular endothelial growth factor (VEGF). VEGF-mediated angiogenesis induces gene expressions and alterations of the actin cytoskeleton upon binding to VEGF receptors (VEGFRs). The aim of this study was to investigate effects of Y-27632 on angiogenesis in post-gastrulation chick embryos during early embryogenesis. After 60 h incubation, embryos in shell-less culture were treated with Y-27632 or vehicle for controls. Y-27632-treated embryos showed reduced extra-embryonic blood vessel formation with impaired circulation of the yolk sac, confirmed by fractal analysis. Western blot confirmed impaired ROCK downstream signaling by decreased expression of phosphorylated myosin light chain. Interestingly, RT-PCR demonstrated increased gene expression of VEGF and VEGFR-2 1 h post-treatment. Protein levels of VEGF were higher in Y-27632-treated embryos at 8 h following treatment, whereas no difference was seen in membranes. We hypothesize that administration of Y-27632 impairs vessel formation during angiogenesis, which may contribute to failure of VWB closure, causing VBWDs.

Prenatal diagnosis of acrania/exencephaly/anencephaly sequence (AEAS): additional structural and genetic anomalies.

To analyse additional structural and genetic anomalies in fetuses with acrania/exencephaly/anencephaly sequence (AEAS). A retrospective analysis of 139 fetuses with AEAS diagnosed between 2006 and 2020 in a single tertiary referral ultrasound department. The median gestational age at diagnosis decreased from 15weeks in 2006 to 13weeks in 2020 (- 0.21 per each year; p = 0.009). In 103 fetuses, the defects were limited to the neural tube (NTD) (74.1%), in 36 fetuses (25.9%), there were additional structural non-NTD anomalies. The most common were ventral body wall defects present in 17.8% (23/139), followed by anomalies of the limbs (7.2%; 10/139), face (6.5%; 9/139) and heart (6.5%; 9/139). Genetic anomalies were diagnosed in 7 of the 74 conclusive results (9.5%; 7/74; trisomy 18, n = 5; triploidy, n = 1; duplication of Xq, n = 1). In univariate logistic regression models, male sex, limb anomalies and ventral body wall defects significantly increased the risk of genetic anomalies (OR 12.3; p = 0.024; OR 16.5; p = 0.002 and OR 10.4; p = 0.009, respectively). A significant number of fetuses with AEAS have additional structural non-NTD anomalies, which are mostly consistent with limb body wall complex. Genetic abnormalities are diagnosed in almost 10% of affected fetuses and trisomy 18 is the most common aberration. Factors that significantly increased the odds of genetic anomalies in fetuses with AEAS comprise male sex, limb anomalies and ventral body wall defects.

Combined pentalogy of Cantrell with ectrodactyly and surgical implant‐free repair of a sternal cleft and supraumbilical hernia in an adult cat

AbstractA 20‐month‐old, British shorthair cat was presented for treatment of a ventral thoracic wall defect. Physical examination showed cleft sternum with supraumbilical body wall defect, an immediately palpable heart under the skin between the cleft halves and a unilateral forelimb ectrodactyly. Survey radiographs and sonographic examination revealed ectopia cordis associated with the sternal cleft, a supraumbilical abdominal hernia, ventral diaphragmatic defect and cardiac abnormalities. Radiography of the dysostotic limb confirmed ectrodactyly. Surgery involved reconstruction of the ventral body wall defects using a transversus abdominis muscle flap supported by an omental flap. Clinical, imaging and intraoperative findings supported the diagnosis of complete pentalogy of Cantrell. The cat recovered from surgery uneventfully and periodic follow‐ups to 17 months after surgery confirmed a good outcome.

OEIS Syndrome: Omphalocele, Exstrophy of the Cloaca, Imperforate Anus, and Spinal Defects

OEIS Syndrome: Omphalocele, Exstrophy of the Cloaca, Imperforate Anus, and Spinal Defects

Teratogenesis in the chick embryo following post-gastrulation exposure to Y-27632 -effect of Y-27632 on embryonic development

The pyridine derivative Y-27632 inhibits Rho-associated coiled-coil-containing protein kinase (ROCK) signaling, which is involved in numerous developmental processes during embryogenesis, primarily by controlling actin-cytoskeleton assembly and cell contractility. Somite formation requires rearrangement of the cytoskeleton and assists in major morphological mechanisms, including ventral body wall formation. Administration of Y-27632 impairs cytoskeletal arrangements in post-gastrulation chick embryos leading to ventral body wall defects (VBWD) at later stages of development. The aim of this study was to investigate the effect of Y-27632 on somite development in post-gastrulation chick embryos during early embryogenesis. After 60 h incubation, embryos in shell-less culture were treated with Y-27632 or vehicle for controls. Following administration, abnormality rates were assessed. In treatment groups, embryos showed a kinked longitudinal body axis. Western blot confirmed impaired ROCK downstream signaling by decreased expression of phosphorylated cofilin-2. Histology, Lysotracker studies and RT-PCR demonstrated increased cell death in somites, the neural tube and the ectoderm. RT-PCR and Western blot of factors known to be involved during somitogenesis revealed reduced expression in the treatment group compared to controls. We hypothesize that administration of Y-27632 disrupts somite development causing axial kinking and embryo malformation, which may lead to VBWD.

Fetal Autopsy Showing Two Ventral Body Wall Defects: An Unusual Presentation

Thoracoschisis and gastroschisis are types of ventral body wall defects. Usually thoracoabdominoschisis presents as a continuous defect. Here the authors present the case of autopsy of 18 weeks old fetus with two well-separated ventral body wall defects. Thoracoschisis was a right lateral thoracic wall defect while gastroschisis, a midline infraumblical abdominal wall defect. Through the right lateral thoracic wall parts of two organs appeared to be protruding. On dissection, 8th and 9th ribs with the liver and the lower lobe of the right lung were herniating outside the body. The right lung was haemorrhagic. Various embryological theories on ventral body wall defects have been discussed in view of the present case.

Mice doubly deficient in Six4 and Six5 show ventral body wall defects reproducing human omphalocele

ABSTRACTOmphalocele is a human congenital anomaly in ventral body wall closure and may be caused by impaired formation of the primary abdominal wall (PAW) and/or defects in abdominal muscle development. Here, we report that mice doubly deficient in homeobox genes Six4 and Six5 showed the same ventral body wall closure defects as those seen in human omphalocele. SIX4 and SIX5 were localized in surface ectodermal cells and somatic mesoderm-derived mesenchymal and coelomic epithelial cells (CECs) in the PAW. Six4−/−;Six5−/− fetuses exhibited a large omphalocele with protrusion of both the liver and intestine, or a small omphalocele with protrusion of the intestine, with complete penetrance. The umbilical ring of Six4−/−;Six5−/− embryos was shifted anteriorly and its lateral size was larger than that of normal embryos at the E11.5 stage, before the onset of myoblast migration into the PAW. The proliferation rates of surface ectodermal cells in the left and right PAW and somatic mesoderm-derived cells in the right PAW were lower in Six4−/−;Six5−/− embryos than those of wild-type embryos at E10.5. The transition from CECs of the PAW to rounded mesothelial progenitor cells was impaired and the inner coelomic surface of the PAW was relatively smooth in Six4−/−;Six5−/− embryos at E11.25. Furthermore, Six4 overexpression in CECs of the PAW promoted ingression of CECs. Taken together, our results suggest that Six4 and Six5 are required for growth and morphological change of the PAW, and the impairment of these processes is linked to the abnormal positioning and expansion of the umbilical ring, which results in omphalocele.

Ringed Placenta: Changes in Placental Perfusion Associated with Increased Mortality with Ventral Body Wall Defect [18E

INTRODUCTION: Purpose is to assess perinatal morbidity/mortality among infants with ventral wall defects (VWD) and abnormal placental perfusion patterns on prenatal MRI. METHODS: A retrospective case series of pregnancies complicated by VWD (omphalocele, OEIS sequence, and bladder exstrophy) performed over a 7-year period. Maternal and infant charts were reviewed for basic demographic data, placental pathology, and neonatal outcomes. MRI studies were reviewed by 2 experts with a specialized focus in fetal MRI. RESULTS: 31 cases of VWD were noted, and 11 cases possessed a novel placental perfusion pattern of a “ringed placenta” (pattern of rings of hyperintense MR signal surrounding hypointense placental cotyledons) seen throughout the parenchyma. In cases with a ringed placenta, five of 11 (45%) survived until 6 months of age. For the control group of VWD without the ringed placenta fourteen of 20 (70%) survived until 6 months of age. The relative risk for stillbirth/neonatal demise vs stillbirth/demise within 24hrs was 1.32 vs. 2.3 in VWD with the ringed placenta. Over 50% of infant demises with abnormal placental findings and 25% of normal placenta finding were found to be small for gestational age (SGA) at birth, while all of the surviving infants were within normal range birth weight for gestational age. CONCLUSION: Compared to those pregnancies without the “ringed placenta, cases of VWD with the ringed placenta had a higher rate of death and were more likely to be SGA at birth. We did not find an increased risk of extremely low birth weights. Further study is needed to characterize this finding.

SPECC1L: A Novel Cytoskeletal Regulator of Epithelial Organization in Craniofacial Morphogenesis

Craniofacial anomalies are extremely common among birth defects, with clefts of the lip and palate affecting approximately 1/700 live‐births. While many contributory genes have been identified, a large proportion of the genetic component of this complex disease is unknown. Thus, there is a continued need to identify additional genes and to understand underlying pathogenetic mechanisms. We first identified heterozygous SPECC1L mutations in two patients with atypical facial clefts and cleft palate. New heterozygous missense SPECC1L mutations have been identified in two autosomal dominant Opitz G/BBB syndrome families with hypertelorism and cleft palate, and in two patients with Teebi hypertelorism syndrome, underscoring the importance of SPECC1L in craniofacial development. To understand the role of SPECC1L, we have generated several mouse models with null and hypomorphic (truncation, in‐frame deletion, missense) mutations. Mutants for these alleles manifest a range of structural malformations, including exencephaly, cleft palate and ventral body wall defects. The homozygous null mutants die by embryonic day 9.5 (E9.5) with an open neural tube and failure of cranial neural crest cells to delaminate from the neuroectoderm. We have shown that the latter is due to increased expression of adherens junction markers in the neuroectoderm and reduced PI3K‐AKT signaling. Homozygous mutants for a hypomorphic allele that results in SPECC1L truncation die perinatally and show midline subepidermal blebbing with no cleft palate. Specc1lnull/hypo compound mutants with moderate SPECC1L deficiency show palate elevation defects at E14.5, which resolve within one embryonic day such that only a few mutants are born with cleft palate. However, these compound mutants show abnormal organization of the oral periderm of palatal shelves and occasional oral adhesions at E13.5. Consistent with these periderm anomalies, SPECC1L expression in the palate requires IRF6, thus making it a novel member of the IRF6/GRHL3 pathway in periderm development. Lastly, homozygous mouse mutants carrying human Opitz G/BBB patient mutation (T397P) show highly penetrant cleft palate, indicating a gain‐of‐function that specifically affects palatogenesis. Given the broad phenotypic spectrum of Specc1l allelic series mutants, our studies indicate that SPECC1L regulates epithelial organization at various stages and in multiple tissues throughout embryonic development.Support or Funding InformationThis research is supported by NIH/NIDCR R01DE026172.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Exposure to sub-lethal dose of a combination insecticide during early embryogenesis influences the normal patterning of mesoderm resulting in incomplete closure of ventral body wall of chicks of domestic hen.

Pesticide exposure to the non target groups especially during embryonic development has quite often resulted in congenital malformations. A commercially available combination insecticide (Ci, 50% chlorpyrifos and 5% cypermethrin) is known to induce ventral body wall defects (VBWDs) wherein abdominal viscera protrude out of the ventral body wall. Herein, an attempt was made to understand the mechanistic insight into Ci induced VBWDs. For this, before incubation, the chick embryos were dosed with the test chemical and then at different developmental stages of incubation, they were monitored for the changes in the expression of certain genes, which are indispensable for the ventral body wall closure since they regulate the cell fate, proliferation and survival. Concurrently, histopathological changes during the embryonic development were examined to corroborate the above observations. The results of mRNA profiling revealed a significant downregulation of Shh on day 4 and upregulation on day 10, while bmp4, Pitx2, E-cadherin, Wnt11, Wnt6, Pxn, MyoD1, Caspase-3, AHR, Cyp3A4, showed a significant upregulation on day 4 and/or on day 10. N-cadherin, fgf8, bmp1 showed no significant changes. The possible means by which these skewed expression patterns of regulatory molecules culminated into the VBWD are discussed.

Sequence variants identification at the KCNQ1OT1:TSS differentially Methylated region in isolated omphalocele cases

BackgroundOmphalocele is a congenital midline ventral body wall defect that can exist as isolated malformation or as part of a syndrome. It can be considered one of the major and most frequent clinical manifestation of Beckwith-Wiedemann Syndrome (BWS) in case of loss of methylation at KCNQ1OT1: Transcription Star Site-Differentially Methylated Region (TSS-DMR) or in presence of CDKN1C mutations. The isolated form of the omphalocele accounts approximately for about the 14% of the total cases and its molecular etiology has never been fully elucidated.MethodsGiven the tight relationship with BWS, we hypothesized that the isolated form of the omphalocele could belong to the heterogeneous spectrum of the BWS associated features, representing an endophenotype with a clear genetic connection. We therefore investigated genetic and epigenetic changes affecting BWS imprinted locus at 11p15.5 imprinted region, focusing in particular on the KCNQ1OT1:TSS DMR.ResultsWe studied 21 cases of isolated omphalocele detected during pregnancy or at birth and identified the following rare maternally inherited variants: i) the non-coding variant G > A at nucleotide 687 (NR_002728.3) at KCNQ1OT1:TSS-DMR, which alters the methylation pattern of the imprinted allele, in one patient; ii) the deletion c.624-629delGGCCCC at exon 1 of CDKN1C, with unknown clinical significance, in two unrelated cases.ConclusionsTaken together, these findings suggest that KCNQ1OT1:TSS-DMR could be a susceptibility locus for the isolated omphalocele.

Discordant Anomalies with Combined Features of Pentalogy of Cantrell and OEIS Complex: A Case Report in Monochorionic Twins

ABSTRACTIntroduction: Ventral body wall defects have various manifestations. Among others, pentalogy of Cantrell (PC) and omphalocele exstrophy imperforate anus spinal abnormalities (OEIS) complex are defects that involve upper and lower anterior midline of body wall, respectively. Although both entities are in a spectrum of ventral body wall defects, the combination of PC and OEIS complex has not been described. Case Report: In this report, we describe an unusual case of congenital ventral body wall defect with combined features of PC and OEIS complex, which discordantly occurred in monochorionic monoamniotic twins. Conclusion: PC and OEIS complex may be related regarding their embryologic origins. The combination may represent the most severe manifestation of ventral body wall defects.

Transgelin-expressing myofibroblasts orchestrate ventral midline closure through TGFβ signalling.

Ventral body wall (VBW) defects are among the most common congenital malformations, yet their embryonic origin and underlying molecular mechanisms remain poorly characterised. Transforming growth factor beta (TGFβ) signalling is essential for VBW closure, but the responding cells are not known. Here, we identify in mouse a population of migratory myofibroblasts at the leading edge of the closing VBW that express the actin-binding protein transgelin (TAGLN) and TGFβ receptor (TGFβR). These cells respond to a temporally regulated TGFβ2 gradient originating from the epithelium of the primary body wall. Targeted elimination of TGFβR2 in TAGLN+ cells impairs midline closure and prevents the correct subsequent patterning of the musculature and skeletal components. Remarkably, deletion of Tgfbr2 in myogenic or chondrogenic progenitor cells does not manifest in midline defects. Our results indicate a pivotal significance of VBW myofibroblasts in orchestrating ventral midline closure by mediating the response to the TGFβ gradient. Altogether, our data enable us to distinguish highly regulated epithelial-mesenchymal signalling and successive cellular migration events in VBW closure that explain early morphological changes underlying the development of congenital VBW defects.

Downregulation of AP-2α Gene Expression in the Cadmium-Induced Ventral Body Wall Defect in the Chick Model

Downregulation of AP-2α Gene Expression in the Cadmium-Induced Ventral Body Wall Defect in the Chick Model

Chick embryo as an animal model for ventral body wall defects

Chick embryo as an animal model for ventral body wall defects

Impaired cytoskeletal arrangements and failure of ventral body wall closure in chick embryos treated with rock inhibitor (Y-27632).

Rho-associated kinase (ROCK) signaling regulates numerous fundamental developmental processes during embryogenesis, primarily by controlling actin-cytoskeleton assembly and cell contractility. ROCK knockout mice exhibit a ventral body wall defect (VBWD) phenotype due to disorganization of actin filaments at the umbilical ring. However, the exact molecular mechanisms leading to VBWD still remain unclear. Improper somitogenesis has been hypothesized to contribute to failure of VBW closure. We designed this study to investigate the hypothesis that administration of ROCK inhibitor (Y-27632) disrupts cytoskeletal arrangements in morphology during early chick embryogenesis, which may contribute to the development of VBWD. At 60h incubation, chick embryos were explanted into shell-less culture and treated with 50µL of vehicle for controls (n=33) or 50µL of 500µM of Y-27632 for the experimental group (Y-27, n=56). At 8h post-treatment, RT-PCR was performed to evaluate mRNA levels of N-cadherin, E-cadherin and connexin43. Immunofluorescence confocal microscopy was performed to analyze the expression and distribution of actin, vinculin and microtubules in the neural tube and somites. A further cohort of embryos was treated in ovo by dropping 50µL of vehicle or 50µL of different concentrations of Y-27632 onto the embryo and allowing development to 12 and 14days for further assessment. Gene expression levels of N-cadherin, E-cadherin and connexin43 were significantly decreased in treated embryos compared with controls (p<0.05). Thickened actin filament bundles were recorded in the neural tube of Y-27 embryos. In somites, cells were dissociated with reduced actin distribution in affected embryos. Clumping of vinculin expression was found in the neural tube and somites, whereas reduced expression of microtubules was observed in Y-27 embryos compared with controls. At 12 and 14days of development, affected embryos presented with an enlarged umbilical ring and herniation of abdominal contents through the defect. ROCK inhibition alters cytoskeletal arrangement during early chick embryogenesis, which may contribute to failure of anterior body wall closure causing VBWD at later stages of development.