The relationship between oxidative stress markers in exhaled breath condensate and respiratory problems in patients with repaired esophageal atresia.

AIM: To evaluate the relationship between respiratory problems and oxidative stress markers in exhaled breath condensate (EBC) of patients with esophageal atresia (EA). METHODS: EA cases with respiratory problems were evaluated retrospectively for age, gender, the type of atresia, surgical treatment, outcome and respiratory symptoms. The results of gastroesophageal reflux (GER) treatment including the use of proton pump inhibitor (PPI) and fundoplication were also documented. EBC samples of 500-1000 µl were obtained by Ecoscreen machine in all cases. The levels of Glutathione (Glut), 8-isoprostane (8-iso), cysteinyl-leukotriene (Cys-LT) were measured with ELISA. Results were compared with healthy control subjects (CG, n = 26) and the relationship between oxidative stress markers and respiratory symptoms was evaluated. The results of GER treatment and oxidative stress markers in EBC were also correlated. RESULTS: Twenty-nine patients with a mean age of 8.8 years (3-14 years) were included. The male/female ratio was 16:13. The EA presented with distal fistula in 27 cases. While no fistula was observed in 1 case, both proximal and distal fistulae were present in another single case. Associated anomalies, most of which were cardiovascular anomalies, were observed in 65.5% (n = 19) of cases. The median Glut level was 1.03 mM/ml (0.93-1.15), iso-8 was 38.8 pg/mL (32.03-76.2) and Cys-LT was 0.44 pg/mL (20.17-61.3) in patients with EA. The median levels of oxidative markers in CG were 1.23 mM/mL (1.13-1.36), 66.3 pg/mL (33.5-106.7), and 56.9 pg/mL (27.4-80.1), respectively. Glut levels were significantly lower in EA cases compared to CG (p = 0.01). There was no significant difference between the groups regarding 8-iso and CYS-LT levels (p = 0.9, p = 1.0). Cys-LT levels were significantly lower in patients with PPI treatment [21.7 pg/mL (18.6-48.1)], when compared to patients without PPI treatment [41.1 pg/mL (22.5-83.1)] (p = 0.04) and healthy subjects [56.9 pg/mL (27.4-80.1)] (p = 0.017). The 8-iso levels were significantly decreased in cases with fundoplication compared to the patients without fundoplication (p = 0.02). CONCLUSION: Glut - an antioxidant agent - levels were significantly lower in EBC of EA cases. The decrease in Cys-LT levels in cases with PPI treatment and in 8-iso levels in patients with fundoplication suggests that the oxidative damage in EBC of EA cases may be correlated with GER and its management. TYPE OF STUDY: Case control study LEVEL OF EVIDENCE: Level III.

Congenital esophageal stenosis: a rare malformation of the foregut.

Congenital esophageal stenosis (CES) is a type of esophageal stenosis, and three histological subtypes (tracheobronchial remnants, fibromuscular thickening or fibromuscular stenosis, and membranous webbing or esophageal membrane) are described. Symptoms of CES usually appears with the introduction of the semisolid alimentation. Dysphagia is the most common symptom, but esophageal food impaction, respiratory distress or failure to thrive can be clinical manifestations of CES. Wide spectrum of differential diagnoses leads to delayed definitive diagnosis and appropriate treatment. Depends on hystological subtype of CES, some treatment procedures (dilation or segmental esophageal resection) are recommended, but individually approach is still important in terms of frequency and type of dilation procedures or type of the surgical treatment. Dysphagia can persist after the treatment and a long follow-up period is recommended. In 33% of patients with CES, a different malformations in the digestive system, but also in the other systems, are described.

Prenatal diagnosis of esophageal atresia: A case of triple negative screening.

Esophageal atresia (EA) is prenatally diagnosed in less than one third of the cases and is usually only suspected. Recently, magnetic resonance imaging (MRI) with dynamic sequence and biochemistry of the amniotic fluid have been proposed to enhance prenatal diagnosis of EA. We report the case of a triple negative screening (ultrasound, MRI with dynamic sequence and biochemistry of the amniotic fluid) with a postnatal diagnosis of EA type III with a small defect. Even using second line tests, prenatal diagnosis of EA remains a challenge.

Interkinetic nuclear migration in the tracheal and esophageal epithelia of the mouse embryo: Possible implications for tracheo-esophageal anomalies.

Interkinetic nuclear migration (INM) is a cell polarity-based phenomenon in which progenitor cell nuclei migrate along the apico-basal axis of the pseudostratified epithelium in synchrony with the cell cycle. INM is suggested to be at least partially cytoskeleton-dependent and to regulate not only the proliferation/differentiation of stem/progenitor cells but also the localized/overall size and shape of organs/tissues. INM occurs in all three of the germ-layer derived epithelia, including the endoderm-derived gut. However, INM has not been documented in the esophagus and respiratory tube arising from the anterior foregut. Esophageal atresia with or without trachea-esophageal fistula (EA/TEF) is a relatively common developmental defect. Transcription factors and signaling molecules have been implicated in EA/TEF, but the etiology of EA/TEF-which has been suggested to involve cell polarity-related mechanisms-remains highly controversial. In the present study, we first examined whether INM exists in the trachea and esophagus of mouse embryos at embryonic day 11.5 (E11.5), just after separation of the two tubes from the anterior foregut. By labeling the DNA-synthesizing stem cell nuclei with 5-ethynyl-2'-deoxyuridine, a nucleotide analogue, and statistically analyzing chronological changes in the distribution pattern of the labeled nuclei by using multidimensional scaling, we showed the existence of INM in both the esophagus and trachea, with differences in the INM magnitude and cycle pattern. We further showed morphological changes from the INM-based pseudostratified single layer to the stratified multilayer in the esophageal epithelium in association with a temporal loss/perturbation of AB polarity, suggesting a possible relation with the pathogenesis of EA/TEF.

Assessment of Clinical Symptoms and Multichannel Intraluminal Impedance and pH Monitoring in Children After Thoracoscopic Repair of Esophageal Atresia and Distal Tracheoesophageal Fistula.

BACKGROUND: Motility disturbances of the esophagus and gastroesophageal reflux disease (GERD) are observed frequently in children after repair of congenital esophageal atresia with distal tracheoesophageal fistula (EA/TEF). Recently, in many pediatric surgical centers, thoracoscopic repair was introduced, which theoretically would change the postoperative course. OBJECTIVES: The goal of the study was to assess physical development, disease symptoms, and GERD symptom frequency in children who underwent thoracoscopic surgery of congenital EA/TEF. MATERIAL AND METHODS: The study comprised 22 children (14 boys and 8 girls), aged 16 to 79 months (average age 47.3 months) after surgery of EA/TEF. Clinical symptoms and physical development were analyzed. In 19 children, multichannel intraluminal esophageal impedance connected with pH-metry (MII/pH) was performed. In 11 patients, esophagogastroduodenoscopy with a histological study of mucosa samples was done. RESULTS: The most frequent symptoms were dysphagia, belching, cough and recurrent bronchitis. In 31.5% of the children, body mass deficiency was observed and in 28.6%, low body mass and short stature. Prematurity was present in half of the patients. Depending on the result of the MII/pH study, the children were divided into two groups: 10 children with GERD and 9 children without diagnosis of gastroesophageal reflux. In the 10 with GERD, acid reflux was diagnosed in 9 and non-acid reflux was diagnosed in one. MII/pH demonstrated statistically significant differences in the number of reflux episodes, reflux index, bolus exposure index, mean time of esophageal exposure and acid exposure and mean acid clearance time in children with GERD in comparison to children without this disease. In 36.4% of children who underwent endoscopy, esophagitis was diagnosed, esophageal stricture in 18% and gastric metaplasia in 9.1%. CONCLUSIONS: In children who underwent corrective thoracoscopic surgery of EA/TEF, GERD caused by motility disorders of the esophagus was frequently observed. These children require constant monitoring and early treatment of the complication.

Lung maturity in esophageal atresia: Experimental and clinical study.

INTRODUCTION: Esophageal atresia and tracheoesophageal fistula (EA-TEF) survivors suffer respiratory morbidity of unclear pathogenesis. Defective lung morphogenesis has been described in the rat model. This study examined fetal lung growth and maturity in rats and patients with EA-TEF. METHODS: Pregnant rats received either adriamycin or vehicle. Control and adriamycin-exposed lungs, with and without EA-TEF, were weighed and processed for RT-PCR, DNA quantification, immunofluorescence and immunoblot analysis of TTF1, VEGF, Sp-B, and α-sma. Twenty human lungs were also processed for immunofluorescence and Alcian-blue staining. RESULTS: Lungs from fetuses with EA-TEF (E21) showed decreased total DNA; FGF7 and TTF1 mRNA expressions were upregulated at E15 and E18, respectively. Protein expression and immunofluorescent distribution of maturity markers were similar. Lungs from stillborns with EA-TEF showed decreased epithelial expression of Sp-B and VEGF whereas those from newborns tended to have less Sp-B and more VEGF and mucous glands. DISCUSSION: The lungs of rats with EA-TEF were hypoplastic but achieved near-normal maturity. Stillborns with EA-TEF exhibited an apparently disturbed differentiation of the airway epithelium. Newborns with EA-TEF demonstrated subtle differences in the expression of differentiation markers, and increased number of mucous glands that could influence postnatal respiratory adaptation and explain some respiratory symptoms of EA-TEF survivors.

Abnormal Sonic hedgehog signaling in the lung of rats with esophageal atresia induced by adriamycin.

BACKGROUND: Abnormal lung development was recently described in the rat model of esophageal atresia and tracheoesophageal fistula (EA-TEF). Since in this condition the ventral-to-dorsal switch of Shh expression in the foregut is disturbed, the present study tested the hypothesis that this abnormal expression at the emergence of the tracheobronchial bud might be translated into the developing lung. METHODS: Pregnant rats received either 1.75 mg/kg i.p. adriamycin or vehicle from E7 to E9. Three groups were studied: control and adriamycin-exposed with and without EA-TEF. Embryos were recovered and the lungs were harvested and processed for reverse transcription polymerase chain reaction and immunofluorescence analysis of the Shh signaling cascade. RESULTS: Shh signaling was downregulated at the late embryonic stage of lung development (E13) in embryos with EA-TEF. Throughout the subsequent stages of development, the expression of both Shh and its downstream components increased significantly and remained upregulated throughout gestation. Immunofluorescent localization was consistent with these findings. CONCLUSION: Defective Shh signaling environment in the foregut is present beyond the emergence of lung buds and probably impairs lung development. Later in gestation, lungs exhibited a remarkable ability to upregulate the Shh cascade, suggesting a compensatory response. These findings may be relevant to understand pulmonary disease suffered by children with EA-TEF.

De novo GLI3 mutation in esophageal atresia: reproducing the phenotypic spectrum of Gli3 defects in murine models.

Esophageal atresia is a common and life-threatening birth defect with a poorly understood etiology. In this study, we analyzed the sequence variants of coding regions for a set of esophageal atresia-related genes including MYCN, SOX2, CHD7, GLI3, FGFR2 and PTEN for mutations using PCR-based target enrichment and next-generation sequencing in 27 patients with esophageal atresia. Genomic copy number variation analysis was performed using Affymetrix SNP 6.0. We found a de novo heterozygous mutation in the N-terminal region of the GLI3 gene (c.332T>C, p.M111T) in a patient with esophageal atresia and hemivertebrae. The N-terminal region (amino acids 1-397) of GLI3 contains the repressor domain, which interacts with SKI family proteins. Using the co-immunoprecipitation assay, we found that interaction of GLI3 with the SKI family protein SKIL was significantly compromised by the p.M111T mutation of GLI3. Thus far, all the identified mutations mapped within the repressor domain of GLI3 were nonsense and frame-shift mutations. In this study, a missense mutation was initially detected in this region. Our finding is the first to link this GLI3 gene mutation with esophageal atresia in humans, which was previously suggested in an animal model.

Does a combination of ultrasound, MRI, and biochemical amniotic fluid analysis improve prenatal diagnosis of esophageal atresia?

OBJECTIVE: Prenatal diagnosis of esophageal atresia (EA) remains a challenge. Our objective was to evaluate the combination of sonography, magnetic resonance imaging (MRI), and amniotic fluid biochemical markers in prenatal diagnosis of EA. STUDY DESIGN: A retrospective study of all cases with prenatal suspicion of EA from January 2008 to May 2013 in our regional reference center was carried out. Patients were included if all the three tests were performed. For each test, sensitivity (Se), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV) were evaluated. Each test was compared using Fisher's exact test. RESULTS: Fifteen patients were referred at a median gestational age of 28(+5) weeks (24-36) for suspicion of EA on the basis of small or non-visualized fetal stomach bubble and/or polyhydramnios. Se, Sp, PPV, and NPV for sonographic pouch sign/MRI/biochemical amniotic fluid were respectively 40/100/100/45.5%, 80/100/100/71.4%, and 90/60/81.8/75%. MRI was the best predictive test (p = 0.007). CONCLUSION: In case of ultrasound prenatal suspicion of EA (with or without visualization of the pouch sign), an MRI at 30-32 weeks using fast imaging employing steady-state acquisition should be proposed. Biochemical amniotic fluid may be helpful and should be evaluated in a larger study.

Specific biochemical amniotic fluid pattern of fetal isolated esophageal atresia.

BACKGROUND: Perinatal care of esophageal atresia (EA) may be improved by prenatal diagnosis. Ultrasound findings (polyhydramnios and/or nonvisualization of fetal stomach) lead to a detection rate of ~50%. An amniotic fluid (AF) biochemical pattern characterized by high total protein, γ-glutamyl transpeptidase (GGTP), and normal l-leucine-aminopeptidase (AMP) leads to a 100% detection rate. The aim of this study was to explain this specific pattern. METHODS: On the basis of enzyme activities assay, the following four objectives were sought: (i) comparing AF markers between EA and other digestive tract atresias, (ii) determining local GGTP synthesis in the esophagus (immunohistobiochemistry), (iii) determining the presence of a specific AF-AMP activity inhibitor, and (iv) comparing AF-AMP and AF-GGTP half-lives. RESULTS: The AF-EA pattern was similar to that observed in upper duodenal atresia (above the Oddi sphincter). No local synthesis of GGTP was observed in the esophagus. No AF-AMP activity inhibitor was found. AF-GGTP had a longer half-life than AF-AMP. CONCLUSION: Due to the swallowing anomaly observed in EA, GGTP and AMP values physiologically observed at 18 wk will decrease on the basis of the half-lives of markers, with a flat slope for GGTP and a sharp slope for AMP, therefore explaining the differences observed in the AF-EA pattern.

Genetic and cellular mechanisms of the formation of esophageal atresia and tracheoesophageal fistula.

Foregut separation involves dynamic changes in the activities of signaling pathways and transcription factors. Recent mouse genetic studies demonstrate that some of these pathways interact with each other to form a complex network, leading to a unique dorsal-ventral patterning in the early foregut. In this review, it is discussed how this unique dorsal-ventral patterning is set prior to the foregut separation and how disruption of this patterning affects the separation process. Roles of downstream targets of these pathways in regulating separation at cellular and molecular levels would be discussed further. Understanding the mechanism of normal separation process will provide insights into the pathobiology of a relatively common birth defect, esophageal atresia with/without tracheoesophageal fistula.

Growth factors, their receptors, neuropeptide-containing innervation, and matrix metalloproteinases in the proximal and distal ends of the esophagus in children with esophageal atresia.

OBJECTIVE: The pathogenesis of esophageal atresia (EA) remains unknown despite a relatively high incidence of this anomaly in population affecting 1 newborn per 3000 live births. The aim of this study was to examine the relative occurrence of growth factors, their receptors, neuropeptide-containing innervation, and tissue-degradating enzymes--matrix metalloproteinases--in the proximal and distal parts of the esophagus with EA. MATERIALS AND METHODS: A histopathological study was conducted on 15 patients with EA. Tissues were processed for NGFRp75, PGP 9.5, TGF-ß, FGFR, VEGF, EGFR and MMP-2 by means of biotin-streptavidin immunohistochemistry. RESULTS: In the control and EA-affected distal esophageal specimens, numerous and abundant NGFR-containing structures were detected, while in the proximal part of the esophagus, a decrease in their number was observed in patients. PGP 9.5 also marked neuronal structures similarly. TGF-ß was found only in occasional cells in the EA-affected esophageal specimens, while control material demonstrated moderate to numerous TGF-ß-containing structures. Abundance of FGFR and only occasional appearance of VEGF-positive cells were found in both the control and EA-affected material. A moderate number of connective tissue cells in controls contained EGFR. Compared with controls, the number of MMP-2 expressing cells in the EA-affected tissues was decreased in the proximal esophagus. CONCLUSIONS: A decrease in PGP 9.5-containing neuronal structures in the proximal esophagus supports insufficient innervation of this part of the organ in EA. A decrease in MMP-2 positive cells in the esophageal atresia-affected proximal esophagus indicates also a possible decrease of tissue adaptive and regenerative reactions. Low expression of TGF-ß and almost the absence of EGFR in the EA-affected specimens may result in disturbances of cell growth, proliferation, and differentiation, indicating a significant role of these substances in morphopathogenesis of EA. FGFR and VEGF seem not to characterize EA pathogenesis.

Fgf10 gene expression is delayed in the embryonic lung mesenchyme in the adriamycin mouse model.

BACKGROUND: The adriamycin mouse model is a well-established teratogenic model of esophageal atresia/tracheoesophageal fistula. Fibroblast growth factor 10 (Fgf10) plays a key role in branching of the lung buds during lung morphogenesis. Fgf10 knockout mice exhibit the absence of the lungs. Optical projection tomography (OPT) is a technique that allows three-dimensional (3D) imaging of gene expression in small tissue specimens in an anatomical context. The aim of this study was to investigate the temporo-spatial expression of Fgf10 during the critical period of separation of the trachea and esophagus in normal and adriamycin-treated embryos using OPT. METHODS: Time-mated CBA/Ca mice received intraperitoneal injections of adriamycin (6 mg/kg) or saline on days 7 and 8 of gestation. Embryos were harvested on days 10-13, stained after whole mount in situ hybridization with labeled RNA probes to detect Fgf10 transcripts (n = 5 for each treatment/day of gestation). Immunolocalization with endoderm marker Hnf3 beta was used to visualize morphology. Embryos were scanned by OPT to obtain 3D representations of gene expression domains. RESULTS: Computer reconstructed specimens allowed precise staging of developing embryos according to Theiler Staging (TS) criteria. OPT elegantly displayed Fgf10 gene expression in the pulmonary mesenchyme around the tip of the lung buds in both controls and treated embryos in the same spatial territory. Fgf10 gene expression was first detected in the control embryos at TS17. However, Fgf10 gene expression in adriamycin-treated embryos was first only observed at TS18 in 67% of the specimens. CONCLUSION: Delayed Fgf10 gene expression during the critical period of separation of the trachea and esophagus may affect lung bud formation in the adriamycin model leading to tracheoesophageal malformations.

Visualizing expression patterns of Shh and Foxf1 genes in the foregut and lung buds by optical projection tomography.

Congenital malformations of the foregut are common in humans. The respiratory and digestive tubes are both derived by division of the foregut primordium. Sonic hedgehog (Shh) and Fork head box F1 (Foxf1) genes encode regulatory molecules that play a pivotal role in gut and lung morphogenesis and are therefore important candidate genes to be examined in models of foregut developmental disruption. Optical projection tomography (OPT) is a new, rapid and non-invasive technique for three-dimensional (3D) imaging of small biological tissue specimens that allows visualization of the tissue distribution of RNA in developing organs while also recording morphology. To explore the application of OPT in this context, we visualized Shh and Foxf1 gene expression patterns in the mouse foregut and lung buds at several stages of development. Time-mated CBA/Ca mice were harvested on embryonic days 9-12. The embryos were stained following whole mount in situ hybridization with labelled RNA probes to detect Shh and Foxf1 transcripts at each stage. The embryos were scanned by OPT to obtain 3D representations of gene expression domains in the context of the changing morphology of the embryo. OPT analysis of Shh and Foxf1 expression in the foregut and lung buds revealed extra details of the patterns not previously reported, particularly in the case of Foxf1 where gene expression was revealed in a changing pattern in the mesenchyme around the developing lung. Shh expression was also revealed in the epithelium of the lung bud itself. Both genes were detected in complementary patterns in the developing bronchi as late as E12, showing successful penetration of molecular probes and imaging at later stages. OPT is a valuable tool for revealing gene expression in an anatomical context even in internal tissues like the foregut and lung buds across stages of development, at least until E12. This provides the possibility of visualizing altered gene expression in an in vivo context in genetic or teratogenic models of congenital malformations.

The structural characteristics and expression of neuropeptides in the esophagus of patients with congenital esophageal atresia and tracheoesophageal fistula.

PURPOSE: The aim of this study was to investigate the structural characteristics and the expression of a group of neuropeptides in the esophagus of patients with congenital esophageal atresia and tracheoesophageal fistula (EA-TEF), as well to elucidate the roles of these neuropeptides in the pathogenesis of postoperative incoordination of esophagus after successful surgical repair of EA-TEF. METHODS: Twenty-four specimens from distal tracheoesophageal fistulas of patients with EA-TEF (EA-TEF group) and 10 esophageal specimens from neonates who died of nonesophageal diseases (control group) were studied. All of the specimens were subjected to routine pathologic study, ultrastructural observation, and immunohistochemical staining for neuron-specific enolase, substance P, vasoactive intestinal polypeptide, and nitric oxide synthase. RESULTS: In the EA-TEF group, mitochondria were distributed along the membrane of smooth muscle cell, whereas mitochondria in the control group were distributed along the karyotheca of the smooth muscle cells. The ratio of granulated vesicles to clear vesicles in the varicosity of the intramuscular motor nerve ending of the EA-TEF group (0.520 +/- 0.137) was much higher than that in the control group (0.192 +/- 0.020, P < .05). The percentages of specimens shown to have positive expression of neuron-specific enolase and substance P in the EA-TEF group (20.8% and 12.5%, respectively) were significantly lower than those in the control group (90% and 80% respectively, P < .05). The percentages of specimens shown to have positive expression of vasoactive intestinal polypeptide and nitric oxide synthase in the EA-TEF group (83.3% and 75%, respectively) were significantly higher than that in the control group (30% and 10% respectively, P < .05). CONCLUSION: Imbalance of neurotransmitters excretion in nerve vesicle, abnormal intrinsic dysplasia of nerve plexus and increased expression of certain neuropeptides were the main characteristics of esophagus with abnormal intrinsic innervation, which may be responsible for the postoperative esophageal dysfunction of EA-TEF.

Multiple dose-dependent roles for Sox2 in the patterning and differentiation of anterior foregut endoderm.

Sox2 is expressed in developing foregut endoderm, with highest levels in the future esophagus and anterior stomach. By contrast, Nkx2.1 (Titf1) is expressed ventrally, in the future trachea. In humans, heterozygosity for SOX2 is associated with anopthalmia-esophageal-genital syndrome (OMIM 600992), a condition including esophageal atresia (EA) and tracheoesophageal fistula (TEF), in which the trachea and esophagus fail to separate. Mouse embryos heterozygous for the null allele, Sox2(EGFP), appear normal. However, further reductions in Sox2, using Sox2(LP) and Sox2(COND) hypomorphic alleles, result in multiple abnormalities. Approximately 60% of Sox2(EGFP/COND) embryos have EA with distal TEF in which Sox2 is undetectable by immunohistochemistry or western blot. The mutant esophagus morphologically resembles the trachea, with ectopic expression of Nkx2.1, a columnar, ciliated epithelium, and very few p63(+) basal cells. By contrast, the abnormal foregut of Nkx2.1-null embryos expresses elevated Sox2 and p63, suggesting reciprocal regulation of Sox2 and Nkx2.1 during early dorsal/ventral foregut patterning. Organ culture experiments further suggest that FGF signaling from the ventral mesenchyme regulates Sox2 expression in the endoderm. In the 40% Sox2(EGFP/COND) embryos in which Sox2 levels are approximately 18% of wild type there is no TEF. However, the esophagus is still abnormal, with luminal mucus-producing cells, fewer p63(+) cells, and ectopic expression of genes normally expressed in glandular stomach and intestine. In all hypomorphic embryos the forestomach has an abnormal phenotype, with reduced keratinization, ectopic mucus cells and columnar epithelium. These findings suggest that Sox2 plays a second role in establishing the boundary between the keratinized, squamous esophagus/forestomach and glandular hindstomach.

Aberrant Bmp signaling and notochord delamination in the pathogenesis of esophageal atresia.

Human foregut malformation known as esophageal atresia with tracheoesophageal fistula (EA/TEF) occurs in 1 in 4,000 live births with unknown etiology. We found that mice lacking Noggin (Nog(-/-)) displayed Type C EA/TEF, the most common form in humans, and notochordal defects strikingly similar to the adriamycin-induced rat EA/TEF model. In accord with esophageal atresia, Nog(-/-) embryos displayed reduction in the dorsal foregut endoderm, which was associated with reduced adhesion and disrupted basement membrane. However, significant apoptosis in the Nog(-/-) dorsal foregut was not observed. Instead, non-notochordal, likely endodermal, cells were found in Nog(-/-) notochord, suggesting that Noggin function is required in the notochordal plate for its proper delamination from the dorsal foregut. Notably, ablating Bmp7 function in Nog(-/-) embryos rescued EA/TEF and notochord branching defects, establishing a critical role of Noggin-mediated Bmp7 antagonism in EA/TEF pathogenesis.

Genetic players in esophageal atresia and tracheoesophageal fistula.

Esophageal atresia is a common and serious developmental anomaly, of which the causes remain largely unknown. Studies in vertebrate models indicate the importance of the sonic hedgehog pathway in esophageal atresia, but its relevance to the human condition remains to be defined. Now, three genes have been identified that cause syndromic forms of esophageal atresia when mutated. NMYC and SOX2 are transcription factors, whereas CHD7 is encoded by a chromodomain helicase DNA-binding gene, important for chromatin structure and gene expression. These new genes broaden our view of human foregut development.

Aberrant fibroblast growth factor receptor 2 signalling in esophageal atresia with tracheoesophageal fistula.

BACKGROUND: Although the pathogenesis of esophageal atresia with tracheoesophageal fistula (EA/TEF) remains unknown, it has been shown that despite its esophageal appearance, the fistula tract originates from respiratory epithelium. The authors now hypothesize that defects in fibroblast growth factor (FGF) signaling contribute to the esophaguslike phenotype of the fistula tract. FGF2R is critical to normal lung morphogenesis and occurs in 2 isoforms (FGF2RIIIb and FGF2RIIIc), each with different ligand-binding specificity. To characterize FGF signaling in the developing EA/TEF, the authors analyzed levels of FGF2R splice variants in experimental EA/TEF. METHODS: The standard Adriamycin-induced EA/TEF model in rats was used. Individual foregut components from Adriamycin-treated and control embryos were processed for real-time, fluorescence-activated semiquantitative reverse transcriptase polymerase chain reaction on gestational days 12.5 and 13.5. RESULTS: Both fistula tract and Adriamycin-treated or normal esophagus showed significantly lower levels of FGF2RIIIb than either Adriamycin-treated lung buds (E12.5, P =.02; E13.5, P <.005) or normal lung buds (E12.5, P <.005; E13.5, P <.01). At E13.5, the fistula tract had lower levels of FGF2RIIIc than either treated (P <.01) or normal lung (P <.05). CONCLUSIONS: Levels of FGF2R in the developing fistula tract resemble that of distal esophagus rather than developing lung. This defect in FGF2RIIIb signaling may account for the nonbranching, esophaguslike phenotype of the fistula, despite its respiratory origin.

Expression of cell adhesion molecules in the adriamycin-induced esophageal atresia rat model.

Cell adhesion molecules are well-known membrane glycoproteins widely expressed during embryonic development that play a crucial role in cell division, migration and differentiation. We investigated the cell-matrix relationship using N-CAM and pan-cadherin adhesion molecules in the adriamycin-induced esophageal atresia (EA) rat model in the hope of finding a clue to the mechanisms of this unique anomaly.Time-mated pregnant Sprague-Dawley rats were given either saline or adriamycin on days 8 and 9 of gestation. Embryos were harvested on the 18th day of gestation. Esophageal specimens obtained from adriamycin-exposed embryos with (EA+) or without esophageal atresia (EA-) and from saline-exposed embryos were immunostained with N-CAM and pan-cadherin primary antisera. The esophageal specimens from control and EA- groups revealed similar immunostaining properties: weak N-CAM and pan-cadherin immunoreactivity. In contrast, the EA+ group showed intense immunoreactivity. Our study demonstrated an increased synthesis of N-CAM and pan-cadherin in the epithelial cells of the atretic esophagus and trachea. These results suggest that embryonic cell-cell and cell-matrix interactions may play a crucial role in the development of adriamycin-induced EA.