Abnormal notochord branching is associated with foregut malformations in the adriamycin treated mouse model

Oesophageal atresia (OA) and tracheooesophageal fistula (TOF) are relatively common human congenital malformations of the foregut where the oesophagus does not connect with the stomach and there is an abnormal connection between the stomach and the respiratory tract. They require immediate corrective surgery and have an impact on the future health of the individual. These abnormalities are mimicked by exposure of rat and mouse embryos in utero to the drug adriamycin. The causes of OA/TOF during human development are not known, however a number of mouse mutants where different signalling pathways are directly affected, show similar abnormalities, implicating multiple and complex signalling mechanisms. The similarities in developmental outcome seen in human infants and in the adriamycin treated mouse model underline the potential of this model to unravel the early embryological events and further our understanding of the processes disturbed, leading to such abnormalities. Here we report a systematic study of the foregut and adjacent tissues in embryos treated with adriamycin at E7 and E8 and analysed between E9 and E12, comparing morphology in 3D in 149 specimens. We describe a spectrum of 8 defects, the most common of which is ventral displacement and branching of the notochord (in 94% of embryos at E10) and a close spatial correspondence between the site of notochord branching and defects of the foregut. In addition gene expression analysis shows altered dorso-ventral foregut patterning in the vicinity of notochord branches. This study shows a number of features of the adriamycin mouse model not previously reported, implicates the notochord as a primary site of disturbance in such abnormalities and underlines the importance of the model to further address the mechanistic basis of foregut congenital abnormalities.     

Tracheal agenesis with broncho-esophageal fistula in VACTERL / TACRD association

Tracheal agenesis (TA) is an extremely rare malformation. We report here autopsy findings in a case of TA with bronchoesophageal fistula of Floyd type III. The other malformations present included laryngeal atresia, Right lung hypolobulation, ventricular septal defect in membranous portion, bilateral cystic renal dysplasia, spleninculus, Meckel''s diverticulum, and imperforate anus. The constellations of malformations present in our case have overlapping features with Vertebral anomalies, Anal atresia, Cardiovascular anomalies, Tracheo-esophageal fistula, Esophageal atresia, Renal anomalies, Limb anomalies and Tracheal atresia or laryngo tracheal atresia, Cardiac anomalies, Renal anomalies, Duodenal atresia association described previously in the literature.     

Association of tracheoesophageal anomalies with visceral and parietal malformations in a human embryo (Carnegie stage 21)

A human embryo (Carnegie stage 21) with tracheoesophageal malformations (esophageal atresia and tracheoesophageal fistula) and anomalies at the caudal end of the embryo (anorectal atresia, rectovesical fistula, vertebral and notochordal defects, and agenesis of the metanephros) was studied. Other anomalies observed were: absence of right umbilical artery, fusion of spinal ganglia, and absence of cloacal outlet of mesonephric ducts. The possible pathogenesis of these associated malformations is discussed.     

VACTERL-H associated with central hypothyroidism: a case report

The VACTERL-H syndrome is a rare combination of vertebral anomalies, anal atresia, congenital heart defects, tracheo-esophageal fistula, abnormalities of kidneys and limb anomalies together with hydrocephalus. This condition is recognized as a hereditary entity with poor prognosis. We present a newborn weighing 3400 g, born by cesarean section to a 27 years old mother who had had an irregular antenatal follow-up. The patient had severe hydrocephalus, proximal esophageal atresia and distal tracheoesophageal fistula, gastric outlet obstruction, imperforated anus and recto-urethral fistula, patent ductus arterious, a bifid scrotum, a vertebral defect, sacral dimple and central hypothyroidism. The patient had no limb defects. The association of central hypothyroidism and VACTERL-H has previously not been reported.     

De novo deletion of chromosome 20q13.33 in a patient with tracheo-esophageal fistula, cardiac defects and genitourinary anomalies implicates GTPBP5 as a candidate gene

BACKGROUND

Tracheo‐esophageal fistula (TEF) with/or without esophageal atresia (EA) is a common congenital malformation that is often accompanied by other anomalies. The causes of this condition are thought to be heterogeneous but are overall not well understood.

CASE REPORT

We identified a patient with a TEF/EA, as well as cardiac and genitourinary anomalies, who was found to have a 0.7 Mb de novo deletion of chromosome 20q13.33. One gene within the deleted interval, GTPBP5, is of particular interest as a candidate gene.

CONCLUSIONS

GTPBP5 bears further study as a cause of TEF/EA accompanied by other malformations. Birth Defects Research (Part A) 2011. © 2011 Wiley‐Liss, Inc.     

Cardiovascular anomalies produced by nimustine hydrochloride in the rat fetus

The cardiovascular teratogenicity of nimustine hydrochloride (ACNU) was studied in rat fetuses. This drug is a nitrosourea derivative anticancer agent and produces alkylation of DNA. Pregnant Donryu rats were treated with single doses of 10, 11 or 13 mg/kg of the teratogen at various stages during gestation. Examination of the hearts was performed by microdissection after sacrificing the animals on the 20th day of gestation. The highest frequency of cardiovascular anomalies was found in the groups treated on the 8th day of gestation, but there was no difference in the rates induced by the three dosages of ACNU administered. The most common cardiovascular anomalies observed were ventricular septal defect (76.8%) and double outlet right ventricle (10.3%). A considerable number of affected fetuses (37/263) showed complex cardiac anomalies with atrioventricular (AV) malalignment and other AV valve anomalies. These anomalies include: double inlet left ventricle, straddling AV valve, atresia or stenosis of the AV valve, and dysplastic AV valve. ACNU appears to be a useful teratogenic agent for inducing complexes of cardiac anomalies which include AV malalignment.     

Genetic and environmental factors in the etiology of esophageal atresia and/or tracheoesophageal fistula: An overview of the current concepts

Esophageal atresia and/or tracheoesophageal fistula (EA/TEF) are severe congenital anomalies. Although recent years have brought significant improvement in clinical treatment, our understanding of the etiology of these defects is lagging. Many genes and genetic pathways have been implicated in the development of EA/TEF, but only a few genes have been shown to be involved in humans, in animals, or in both. Extrapolating data from animal models to humans is not always straightforward. Environmental factors may also carry a risk, but the mechanisms are yet to be elucidated. This review gives an overview of the current state of knowledge about both genetic and environmental risk factors in the etiology of EA/TEF. Birth Defects Research (Part A) 2009. © 2009 Wiley‐Liss, Inc.     

Unusual presentation of biliary atresia splenic malformation syndrome with autosomal dominant hypospadias

Biliary atresia is associated with polysplenia in 2-10% of cases and is defined as Biliary Atresia Splenic Malformation syndrome (BASM). The main features of BASM syndrome include extrahepatic biliary atresia and polysplenia besides the characteristic findings of laterality anomalies, cardiac anomalies, intraabdominal vascular anomalies, pancreatic anomalies and malrotation. Here we present a 6-month-old male patient with BASM having atrial septal defect, umblical hernia, inguinal hernia, and hypospadias. Clinical history revealed that his father also had hypospadias which showed a rare form of autosomal dominant inheritance. The karyotype was normal and the molecular analysis of CFC1 gene revealed no mutation. We emphasize the importance of a detailed physical examination in cases with BASM.     

Pharmacologic treatment of hyperthyroidism during pregnancy

Clinical hyperthyroidism has been associated with an increased risk of maternal, fetal, and neonatal complications. The available antithyroid drugs are methimazole/carbimazole and propylthiouracil. Several case reports and some epidemiologic studies suggest that methimazole/carbimazole exposure during the first trimester of pregnancy is associated with an increased risk of congenital malformations, including ectodermal anomalies, choanal atresia, esophageal atresia, and omphalocele. However, the absolute risk appears to be very small, and it remains unclear whether the association is driven by the maternal disease, the medication, or the combination of both factors. Propylthiouracil exposure has not been associated with an increased risk of congenital malformations and is the recommended drug during the first trimester of pregnancy. Since propylthiouracil-induced hepatotoxicity has been reported in approximately 0.1% of exposed adults and the number of case-reports of severe liver injury is increasing, treatment with low dose methimazole during the second and third trimesters should be considered. Until now, there has been no evidence that children prenatally exposed to methimazole/carbimazole or propylthiouracil have an increased risk of neurodevelopmental delay.     

<Emphasis Type="Italic">Pcsk5</Emphasis> is required in the early cranio-cardiac mesoderm for heart development

Background

Loss of proprotein convertase subtilisin/kexin type 5 (Pcsk5) results in multiple developmental anomalies including cardiac malformations, caudal regression, pre-sacral mass, renal agenesis, anteroposterior patterning defects, and tracheo-oesophageal and anorectal malformations, and is a model for VACTERL/caudal regression/Currarino syndromes (VACTERL association - Vertebral anomalies, Anal atresia, Cardiac defects, Tracheoesophageal fistula and/or Esophageal atresia, Renal & Radial anomalies and Limb defects).

Results

Using magnetic resonance imaging (MRI), we examined heart development in mouse embryos with zygotic and cardiac specific deletion of Pcsk5. We show that conditional deletion of Pcsk5 in all epiblastic lineages recapitulates all developmental malformations except for tracheo-esophageal malformations. Using a conditional deletion strategy, we find that there is an essential and specific requirement for Pcsk5 in the cranio-cardiac mesoderm for cardiogenesis, but not for conotruncal septation or any other aspect of embryonic development. Surprisingly, deletion of Pcsk5 in cardiogenic or pharyngeal mesodermal progenitors that form later from the cranio-cardiac mesoderm does not affect heart development. Neither is Pcsk5 essential in the neural crest, which drives conotruncal septation.

Conclusions

Our results suggest that Pcsk5 may have an essential and early role in the cranio-cardiac mesoderm for heart development. Alternatively, it is possible that Pcsk5 may still play a critical role in Nkx2.5-expressing cardiac progenitors, with persistence of mRNA or protein accounting for the lack of effect of deletion on heart development.

     

In vitro fertilization (IVF) in Sweden: risk for congenital malformations after different IVF methods

BACKGROUND: The possible excess of congenital malformations in infants born after in vitro fertilization (IVF) has been much discussed in the literature, with controversial conclusions. This population based study is aimed at analyzing the presence of congenital malformations in a large group of infants born after IVF and to compare malformation risk both with that of all infants born and according to IVF method used. METHODS: Infants born after IVF during the period 1982-2001 were ascertained from all IVF clinics in Sweden. The presence of congenital malformations was identified from three national health registers: the Swedish Medical Birth Register, the Swedish Registry of Congenital Malformations, and the Swedish Hospital Discharge Register. The IVF children were compared with all children born in Sweden during the same period and recorded in the Swedish Medical Birth Register. RESULTS: Among 16,280 IVF children (30% conceived after intracytoplasmatic sperm injection [ICSI]) a 42% excess of any congenital malformation was found, explainable by parental characteristics and in some cases by the high rate of multiple births. Among these children, 8% had a congenital malformation, and 5% had a relatively severe condition. For neural tube defects, choanal atresia, and alimentary tract atresia, an additional risk increase was seen. There was no difference in malformation rate according to IVF method except for an excess of hypospadias after ICSI. CONCLUSIONS: An increased risk for congenital malformations occurs after IVF, similar for the different IVF techniques used, and mainly a consequence of parental characteristics. A few specific conditions show an extra increase in risk.     

The phenotype of 45,X/46,XY mosaicism: an analysis of 92 prenatally diagnosed cases.

We undertook an international survey of prenatally diagnosed 45,X/46,XY mosaicism to ascertain the phenotypic spectrum of this condition. Ninety-two cases were obtained by means of a questionnaire sent to over 730 cytogenetic laboratories. Seventy-six cases (75 males and 1 female) had physical examinations after delivery or termination of pregnancy. Among these, there were four significant genital anomalies: three hypospadias and one female with clitoromegaly. Gonadal histology was abnormal in three (27%) of 11 cases, all of whom had normal male external genitalia. Other anomalies were noted in five cases: one cystic hygroma in a male, two cardiac anomalies, one spina bifida with multiple other defects, and one intrauterine growth retardation. There was no relationship between the percent mosaicism and the presence or degree of abnormalities. We conclude that 95% of 45,X/46,XY fetuses will have normal male genitalia, although there will also be a significant risk (27%) for abnormal gonadal histology. Long-term follow-up studies of prenatally diagnosed cases of 45,X/46,XY mosaicism are needed to study, without ascertainment bias, stature, pubertal development, tumor risk, and fertility.     

Esophageal Atresia and Tracheo-Esophageal Fistula — 25 Years' Experience and Current Management

A review of the experience with esophageal atresia and tracheoesophageal fistula over a 25-year period appears to lead to the advisability of the following procedures in surgical management:• Emergency gastrostomy under local anesthesia in all patients.• Extrapleural interruption of tracheo-esophageal fistula and end-to-end esophago-esophagostomy in patients who have the common type of upper esophageal atresia with distal tracheo-esophageal fistula.• Upper esophageal stretching and eventual esophago-esophagostomy in patients with proximal and distal esophageal atresia with or without proximal tracheo-esophageal fistula.     

Mutation Screening and Array Comparative Genomic Hybridization Using a 180K Oligonucleotide Array in VACTERL Association

In order to identify genetic causes of VACTERL association (V vertebral defects, A anorectal malformations, C cardiac defects, T tracheoesofageal fistula, E esophageal atresia, R renal anomalies, L limb deformities), we have collected DNA samples from 20 patients diagnosed with VACTERL or with a VACTERL-like phenotype as well as samples from 19 aborted fetal cases with VACTERL. To investigate the importance of gene dose alterations in the genetic etiology of VACTERL association we have performed a systematic analysis of this cohort using a 180K array comparative genomic hybridization (array-CGH) platform. In addition, to further clarify the significance of PCSK5, HOXD13 and CHD7 genes in the VACTERL phenotype, mutation screening has been performed. We identified pathogenic gene dose imbalances in two fetal cases; a hemizygous deletion of the FANCB gene and a (9;18)(p24;q12) unbalanced translocation. In addition, one pathogenic mutation in CHD7 was detected, while no apparent disease-causing mutations were found in HOXD13 or PCSK5. Our study shows that although large gene dose alterations do not seem to be a common cause in VACTERL association, array-CGH is still important in clinical diagnostics to identify disease cause in individual cases.     

National estimates and race/ethnic-specific variation of selected birth defects in the United States, 1999-2001

BACKGROUND: In the United States, birth defects affect approximately 3% of all births, are a leading cause of infant mortality, and contribute substantially to childhood morbidity. METHODS: Population-based data from the National Birth Defects Prevention Network were combined to estimate the prevalence of 21 selected defects for 1999-2001, stratified by surveillance system type. National prevalence was estimated for each defect by pooling data from 11 states with active case-finding, and adjusting for the racial/ethnic distribution of US live births. We also assessed racial/ethnic variation of the selected birth defects. RESULTS: National birth defect prevalence estimates ranged from 0.82 per 10,000 live births for truncus arteriosus to 13.65 per 10,000 live births for Down syndrome. Compared with infants of non-Hispanic (NH) white mothers, infants of NH black mothers had a significantly higher birth prevalence of tetralogy of Fallot, lower limb reduction defects, and trisomy 18, and a significantly lower birth prevalence of cleft palate, cleft lip with or without cleft palate, esophageal atresia/tracheoesophageal fistula, gastroschisis, and Down syndrome. Infants of Hispanic mothers, compared with infants of NH white mothers, had a significantly higher birth prevalence of anencephalus, spina bifida, encephalocele, gastroschisis, and Down syndrome, and a significantly lower birth prevalence of tetralogy of Fallot, hypoplastic left heart syndrome, cleft palate without cleft lip, and esophageal atresia/tracheoesophageal fistula. CONCLUSIONS: This study can be used to evaluate individual state surveillance data, and to help plan for public health care and educational needs. It also provides valuable data on racial/ethnic patterns of selected major birth defects.     

Effect in rats of simultaneous prenatal exposure to ochratoxin A and aflatoxin B1. I. Maternal toxicity and fetal malformations

Ochratoxin A (OA) and Aflatoxin B1 (AFB1), the food borne mycotoxins are produced by several fungal species of the genera Aspergillus and Penicillium. To determine the teratogenic effects, these mycotoxins were administered orally either individually or in combination to the pregnant Wistar rats on days 6-15 of gestation. OA and AFB1 were dissolved in corn oil and different doses of OA (0.125, 0.25, 0.50, and 0.75 mg/kg), AFB1 (0.125, 0.25, 0.50, and 1.00 mg/kg), and a combination of OA+AFB1 (0.125+0.125; 0.25+0.50; 0.50+0.25 mg/kg) were given by gastric intubation to rats. During dosing period, the body weight and body weight gains significantly decreased at a higher dosage, in both individual and combined treatments. In all the combination treatments, the percent implants resorbed, fetal body weights, and crown-rump lengths were comparable to those of controls and with the individual mycotoxin treatment. The number of dead fetuses was significantly increased in the high OA combination (OA+AFB1 0.50+0.25) group as compared with the other two combinations. OA and AFB1 alone and in combination caused various gross, skeletal, and visceral anomalies. The occurrence was considerably less pronounced in fetuses of AFB1 and combination groups as compared with those of OA group fetuses. The exencephaly, incomplete closure of skull, wavy and fused ribs, agenesis of the ischium bone, and enlarged renal pelvis, recorded in OA treatment and ear abnormality and incomplete ossification of skull bones observed in AFB1 when given individually, were not seen in combination groups. However, new manifestations, such as gastroschisis and syndactyly were observed and the incidence of cardiac defects was increased in fetuses due to the combined treatment. The results of the present study indicated that there is some interaction between these mycotoxins that resulted in reduced teratogenic activity of OA in the presence of AFB1. Apparently, new manifestations observed in combination treatment points to the potential threat of teratogenicity in terms of public health hazards.     

Pentacyclic triterpene oleanolic acid protects against cardiac aging through regulation of mitophagy and mitochondrial integrity

Advanced aging exhibits altered cardiac geometry and function involving mitochondrial anomaly. Natural compounds display promises in the regulation of cardiac homeostasis via governance of mitochondrial integrity in aging. This study examined the effect of oleanolic acid (OA), a natural pentacyclic triterpenoid with free radical scavenging and P450 cyclooxygenase-regulating properties, on cardiac aging and mechanisms involved with a focus on mitophagy. Young (4–5 month-old) and old (22–24 month-old) mice were treated with OA for 6 weeks prior to assessment of cardiac function, morphology, ultrastructure, mitochondrial integrity, cell death and autophagy. Our data revealed that OA treatment alleviated aging-induced changes in myocardial remodeling (increased heart weight, chamber size, cardiomyocyte area and interstitial fibrosis), contractile function and intracellular Ca²⁺ handling, apoptosis, necroptosis, inflammation, autophagy and mitophagy (LC3B, p62, TOM20 and FUNDC1 but not BNIP3 and Parkin). OA treatment rescued aging-induced anomalies in mitochondrial ultrastructure (loss of myofilament alignment, swollen mitochondria, increased circularity), mitochondrial biogenesis and O₂^? production without any notable effect at young age. Interestingly, OA-offered benefit against cardiomyocyte aging was nullified by deletion of the mitophagy receptor FUNDC1 using FUNDC1 knockout mice, denoting an obligatory role for FUNDC1 in OA-elicited preservation of mitophagy. OA reconciled aging-induced changes in E3 ligase MARCH5 but not FBXL2, and failed to affect aging-induced rises in IP3R3. Taken together, our data indicated a beneficial role for OA in attenuating cardiac remodeling and contractile dysfunction in aging through a FUNDC1-mediated mechanism.     

Do infants with major congenital anomalies have an excess of macrosomia?

BACKGROUND: Infants that develop congenital anomalies may also have an excess prevalence of macrosomia (birth weight > or =4,000 g). This may indicate that abnormalities of glycemic control play a role in the etiology of birth defects. This study was undertaken to determine whether all infants with congenital anomalies have an excess of macrosomia and whether it is confined to specific types of anomalies. METHODS: A case-control study was conducted, comparing the birth weights of 8,226 infants with congenital anomalies ascertained by the Texas Birth Defects Monitoring Division with those of 965,965 infants without birth defects. Odds ratios were calculated to determine the association between birth weight and congenital anomalies, for 45 specific defects, and for all these defects combined. RESULTS: For all 45 defects combined, a significant association occurred only in the highest birth weight category. Infants with congenital anomalies were more likely than infants without birth defects to have a birth weight > or =4,500 g (OR = 1.65; 95% CI = 1.39-1.96). Infants born with ventricular septal defects, atrial septal defects, ventricular hypertrophy, or anomalies of the great vessels were 1.5-2.5 times more likely to weigh > or =4,000 g than were infants without birth defects. Based on small numbers, a stronger excess of macrosomia was observed for infants with encephalocele, holoprosencephaly, anomalies of the corpus callosum, preaxial polydactyly, and omphalocele. CONCLUSIONS: Our data suggest that infants with specific congenital anomalies are more likely to be macrosomic than are infants without an anomaly. If these findings are confirmed, associations between macrosomia and specific types of birth defects may help to identify birth defects that are caused by alterations in glycemic control.     

Maternal obesity and morbid obesity: The risk for birth defects in the offspring

BACKGROUND : The objective of this study was to assess, in a large data set from Swedish Medical Health Registries, whether maternal obesity and maternal morbid obesity were associated with an increased risk for various structural birth defects. METHODS : The study population consisted of 1,049,582 infants born in Sweden from January 1, 1995, through December 31, 2007, with known maternal weight and height data. Women were grouped in six categories of body mass index (BMI) according to World Health Organization classification. Infants with congenital birth defects were identified from three sources: the Swedish Medical Birth Registry, the Register of Birth Defects, and the National Patient Register. Maternal age, parity, smoking, and year of birth were thought to be potential confounders and were included as covariates in the adjusted odds ratio analyses. RESULTS : Ten percent of the study population was obese. Morbid obesity (BMI ≥ 40) occurred in 0.7%. The prevalence of congenital malformations was 4.7%, and the prevalence of relatively severe malformations was 3.2%. Maternal prepregnancy morbid obesity was associated with neural tube defects OR 4.08 (95% CI 1.87–7.75), cardiac defects OR 1.49 (95% CI 1.24–1.80), and orofacial clefts OR 1.90 (95% CI 1.27–2.86). Maternal obesity (BMI ≥ 30) significantly increased the risk of hydrocephaly, anal atresia, hypospadias, cystic kidney, pes equinovarus, omphalocele, and diaphragmatic hernia. CONCLUSION : The risk for a morbidly obese pregnant woman to have an infant with a congenital birth defect is small, but for society the association is important in the light of the ongoing obesity epidemic. Birth Defects Research (Part A), 2010. © 2009 Wiley‐Liss, Inc.