Respiratory Morbidity in Children with Repaired Congenital Esophageal Atresia with or without Tracheoesophageal Fistula.

Congenital esophageal atresia with or without tracheoesophageal fistula (CEA ± TEF) is a relatively common malformation that occurs in 1 of 2500-4500 live births. Despite the refinement of surgical techniques, a considerable proportion of children experience short- and long-term respiratory complications, which can significantly affect their health through adulthood. This review focuses on the underlying mechanisms and clinical presentation of respiratory morbidity in children with repaired CEA ± TEF. The reasons for the short-term pulmonary impairments are multifactorial and related to the surgical complications, such as anastomotic leaks, stenosis, and recurrence of fistula. Long-term respiratory morbidity is grouped into four categories according to the body section or function mainly involved: upper respiratory tract, lower respiratory tract, gastrointestinal tract, and aspiration and dysphagia. The reasons for the persistence of respiratory morbidity to adulthood are not univocal. The malformation itself, the acquired damage after the surgical repair, various co-morbidities, and the recurrence of lower respiratory tract infections at an early age can contribute to pulmonary impairment. Nevertheless, other conditions, including smoking habits and, in particular, atopy can play a role in the recurrence of infections. In conclusion, our manuscript shows that most children born with CEA ± TEF survive into adulthood, but many comorbidities, mainly esophageal and respiratory issues, may persist. The pulmonary impairment involves many underlying mechanisms, which begin in the first years of life. Therefore, early detection and management of pulmonary morbidity may be important to prevent impairment in pulmonary function and serious long-term complications. To obtain a successful outcome, it is fundamental to ensure a standardized follow-up that must continue until adulthood.

Role of High-Resolution Chest Computed Tomography in a Child with Persistent Tachypnoea and Intercostal Retractions: A Case Report of Neuroendocrine Cell Hyperplasia.

Background: Chronic interstitial lung diseases in children (chILD) are a heterogeneous group of disorders that can represent a clinical challenge for pediatric pneumologists. Among them, neuroendocrine cell hyperplasia of infancy (NEHI) is a diffuse lung disease prevalent in the first years of life that spontaneously improves over time. The clinical presentation of NEHI is indistinguishable from other interstitial lung diseases, so a correct and non-invasive diagnosis by chest computed tomography (CT) without lung biopsy might not be simple. Case presentation: An 8-month-old male infant presented with a history of chronic tachypnoea and dyspnoea since 6 months of age. The patient was born at term, with APGAR scores of 9 and 10 at 1 and 5 min, respectively. Since his second month of life, the patient suffered from abnormal breathing, which was characterized by mild tachypnoea and costal retractions that worsened during breastfeeding, crying, and respiratory infections. Bilateral inspiratory crackles, preferential to the lung bases, without oxygen desaturation were detected. A chest X-ray showed a diffuse over-inflation of the lungs, but laboratory tests did not reveal any abnormalities. High-resolution chest CT documented patchy areas of ground-glass opacity involving the right upper lobe, middle lobe, and lingula, and showed mosaic areas of air-trapping, suggesting a diagnosis of NEHI. The infant was discharged without therapy and gradually improved over time. At 1 year of age, the patient was eupnoeic and chest auscultation had normalized. Conclusions: NEHI is an interstitial disease of infancy characterized by tachypnoea from the first months of life, with a good prognosis and for which a rational diagnostic approach is crucial for making a specific, early diagnosis. Initially, clinical suspicions can be confirmed with reasonable accuracy by a CT scan of the chest. Other more invasive and more expensive investigations should be reserved for selected cases that do not show a spontaneous, favourable clinical evolution.

An Update on the Therapeutic Approach to Vernal Keratoconjunctivitis.

Vernal keratoconjunctivitis (VKC) is an inflammatory disease of the ocular surface. It commonly occurs in the first decade of life, has a wide geographical distribution, and usually occurs in warm, dry areas. The pathogenesis of VKC seems to have an immune, nervous, and endocrine basis. The most common eye symptoms are itching, discharge, tearing, eye irritation, redness of the eyes, and photophobia. Although VKC generally has a good prognosis, the lack of clarity regarding the origin of the disease makes treatment a challenge for pediatricians and ophthalmologists. The purpose of this review is to discuss the pathogenesis, clinical features, and diagnostic criteria in VKC, with a focus on its therapeutic management. The selection of a therapeutic scheme from the many available options is based on clinical features and the personal preferences of both physicians and patients. Due to the lack of uniform grading of disease severity, there is no worldwide consensus on first-line and second-line therapeutic approaches. The choice of treatment for long-term moderate to severe VKC includes topical cyclosporine or tacrolimus. Further data are needed to define the minimal effective concentration and the safety of these drugs in eye drops and to clarify the diagnosis of VKC in patients who require these drugs. Finally, while promising newly discovered drugs are expected to enter into clinical practice, further studies on their efficacy and safety are required.

Partial comparison of the NxTAG Respiratory Pathogen Panel Assay with the Luminex xTAG Respiratory Panel Fast Assay V2 and singleplex real-time polymerase chain reaction for detection of respiratory pathogens.

In this study, 185 nasopharyngeal swabs were tested to compare the sensitivity and specificity of the Luminex NxTAG (NxTAG) Respiratory Pathogen Panel (RPP) Assay with those of the Luminex Respiratory Virus Panel (RVP) Fast Assay v2 and singleplex real-time polymerase chain reaction (PCR). The NxTAG Assay identified at least one infectious agent in 164 (88.7%) of the swabs. In 91 (6.2%) tests with negative results with the RVP Fast Assay v2, a virus was identified by the NxTAG (P < 0.001). With the NxTAG Assay, the detection rates were significantly higher for respiratory syncytial virus (P = 0.003), human metapneumovirus (P < 0.001), human rhinovirus/human enterovirus (P = 0.009) and human adenovirus (P < 0.001). Finally, the NxTAG Assay identified M. pneumoniae in 32 of 44 (72.7%) PCR-positive samples. However, the concordance with real-time PCR results was low for both assays. In conclusion, the results indicate that the NxTAG Assay overcomes some of the limitations of previous Luminex assays, although further studies are needed for a more complete evaluation of the new assay.

Epidemiology and Clinical Characteristics of Respiratory Infections Due to Adenovirus in Children Living in Milan, Italy, during 2013 and 2014.

To evaluate the predominant human adenovirus (HAdV) species and types associated with pediatric respiratory infections, nasopharyngeal swabs were collected from otherwise healthy children attending an emergency room in Milan, Italy, due to a respiratory tract infection from January 1 to February 28 of two subsequent years, 2013 and 2014. The HAdVs were detected using a respiratory virus panel fast assay (xTAG RVP FAST v2) and with a HAdV-specific real-time polymerase chain reaction; their nucleotides were sequenced, and they were tested for positive selection. Among 307 nasopharyngeal samples, 61 (19.9%) tested positive for HAdV. HAdV was the only virus detected in 31/61 (50.8%) cases, whereas it was found in association with one other virus in 25 (41.0%) cases and with two or more viruses in 5 (8.2%) cases. Human Enterovirus/human rhinovirus and respiratory syncytial virus were the most common co-infecting viral agents and were found in 12 (19.7%) and 7 (11.5%) samples, respectively. Overall, the HAdV strain sequences analyzed were highly conserved. In comparison to HAdV-negative children, those infected with HAdV had a reduced frequency of lower respiratory tract involvement (36.1% vs 55.2%; p = 0.007), wheezing (0.0% vs 12.5%; p = 0.004), and hospitalization (27.9% vs 56.1%; p<0.001). Antibiotic therapy and white blood cell counts were more frequently prescribed (91.9% vs 57.1%; p = 0.04) and higher (17,244 ± 7,737 vs 9,565 ± 3,211 cells/µL; p = 0.04), respectively, in children infected by HAdV-C than among those infected by HAdV-B. On the contrary, those infected by HAdV-B had more frequently lower respiratory tract involvement (57.1% vs 29.7%) but difference did not reach statistical significant (p = 0.21). Children with high viral load were absent from child care attendance for a longer period of time (14.5 ± 7.5 vs 5.5 ± 3.2 days; p = 0.002) and had higher C reactive protein levels (41.3 ± 78.5 vs 5.4 ± 9.6 µg/dL; p = 0.03). This study has shown that HAdV infections are diagnosed more commonly than usually thought and that HAdVs are stable infectious agents that do not frequently cause severe diseases. A trend toward more complex disease in cases due to HAdV species C and in those with higher viral load was demonstrated. However, further studies are needed to clarify factors contributing to disease severity to understand how to develop adequate preventive and therapeutic measures.

The significance of low DBP in US adults with isolated systolic hypertension.

OBJECTIVES: To determine the features of isolated systolic hypertension (ISH), the most common hypertensive subtype in persons at least age 50, associated with greater cardiovascular disease (CVD) risk when accompanied by low diastolic blood pressure (DBP). DESIGN: Data were obtained from adult hypertensives at least age 18 in the National Health Nutrition Examination Survey (NHANES) 1999-2006 (n = 19 808, projected to 199.3 million). METHOD: ISH were categorized by low DBP (< 70 mmHg) vs. higher DBP (≥ 70-89 mmHg), treatment status, age, sex, ethnicity, cardiometabolic risk factors, and comorbidities. RESULTS: A 58.6% of all untreated US hypertensives had ISH (mean blood pressure 154.3/73.8 mmHg). Untreated and treated persons with ISH and DBP less than 70 mmHg represented 30 and 35%, respectively, of the ISH population and had almost twice the prevalence of diabetes and CVD, but a lower prevalence of the metabolic syndrome (P < 0.05 to P < 0.01). There was a three-fold greater prevalence of CVD from the highest to the lowest DBP strata in untreated ISH (P < 0.01). Logistic regression showed that age, female sex, and diabetes, but not treatment status, were independently associated with lower DBP (all P < 0.01). Of those persons with ISH and DBP less than 70 mmHg, 45% remain untreated. CONCLUSION: Older persons with untreated ISH and DBP less than 70 mmHg, comprising almost one-third of the untreated ISH population, had greater prevalence of diabetes and CVD than persons with ISH in association with DBP 70-89 mmHg. Intensified efforts to identify and adequately treat these individuals are needed to reduce their associated CVD risk.

Chromatin remodelling complex dosage modulates transcription factor function in heart development.

Dominant mutations in cardiac transcription factor genes cause human inherited congenital heart defects (CHDs); however, their molecular basis is not understood. Interactions between transcription factors and the Brg1/Brm-associated factor (BAF) chromatin remodelling complex suggest potential mechanisms; however, the role of BAF complexes in cardiogenesis is not known. In this study, we show that dosage of Brg1 is critical for mouse and zebrafish cardiogenesis. Disrupting the balance between Brg1 and disease-causing cardiac transcription factors, including Tbx5, Tbx20 and Nkx2-5, causes severe cardiac anomalies, revealing an essential allelic balance between Brg1 and these cardiac transcription factor genes. This suggests that the relative levels of transcription factors and BAF complexes are important for heart development, which is supported by reduced occupancy of Brg1 at cardiac gene promoters in Tbx5 haploinsufficient hearts. Our results reveal complex dosage-sensitive interdependence between transcription factors and BAF complexes, providing a potential mechanism underlying transcription factor haploinsufficiency, with implications for multigenic inheritance of CHDs.

Shox2 mediates Tbx5 activity by regulating Bmp4 in the pacemaker region of the developing heart.

Heart formation requires a highly balanced network of transcriptional activation of genes. The homeodomain transcription factor, Shox2, is essential for the formation of the sinoatrial valves and for the development of the pacemaking system. The elucidation of molecular mechanisms underlying the development of pacemaker tissue has gained clinical interest as defects in its patterning can be related to atrial arrhythmias. We have analyzed putative targets of Shox2 and identified the Bmp4 gene as a direct target. Shox2 interacts directly with the Bmp4 promoter in chromatin immunoprecipitation assays and activates transcription in luciferase-reporter assays. In addition, ectopic expression of Shox2 in Xenopus embryos stimulates transcription of the Bmp4 gene, and silencing of Shox2 in cardiomyocytes leads to a reduction in the expression of Bmp4. In Tbx5(del/+) mice, a model for Holt-Oram syndrome, and Shox2(-/-) mice, we show that the T-box transcription factor Tbx5 is a regulator of Shox2 expression in the inflow tract and that Bmp4 is regulated by Shox2 in this compartment of the embryonic heart. In addition, we could show that Tbx5 acts cooperatively with Nkx2.5 to regulate the expression of Shox2 and Bmp4. This work establishes a link between Tbx5, Shox2 and Bmp4 in the pacemaker region of the developing heart and thus contributes to the unraveling of the intricate interplay between the heart-specific transcriptional machinery and developmental signaling pathways.

Early chordate origins of the vertebrate second heart field.

The vertebrate heart is formed from diverse embryonic territories, including the first and second heart fields. The second heart field (SHF) gives rise to the right ventricle and outflow tract, yet its evolutionary origins are unclear. We found that heart progenitor cells of the simple chordate Ciona intestinalis also generate precursors of the atrial siphon muscles (ASMs). These precursors express Islet and Tbx1/10, evocative of the splanchnic mesoderm that produces the lower jaw muscles and SHF of vertebrates. Evidence is presented that the transcription factor COE is a critical determinant of ASM fate. We propose that the last common ancestor of tunicates and vertebrates possessed multipotent cardiopharyngeal muscle precursors, and that their reallocation might have contributed to the emergence of the SHF.

Reptilian heart development and the molecular basis of cardiac chamber evolution.

The emergence of terrestrial life witnessed the need for more sophisticated circulatory systems. This has evolved in birds, mammals and crocodilians into complete septation of the heart into left and right sides, allowing separate pulmonary and systemic circulatory systems, a key requirement for the evolution of endothermy. However, the evolution of the amniote heart is poorly understood. Reptilian hearts have been the subject of debate in the context of the evolution of cardiac septation: do they possess a single ventricular chamber or two incompletely septated ventricles? Here we examine heart development in the red-eared slider turtle, Trachemys scripta elegans (a chelonian), and the green anole, Anolis carolinensis (a squamate), focusing on gene expression in the developing ventricles. Both reptiles initially form a ventricular chamber that homogenously expresses the T-box transcription factor gene Tbx5. In contrast, in birds and mammals, Tbx5 is restricted to left ventricle precursors. In later stages, Tbx5 expression in the turtle (but not anole) heart is gradually restricted to a distinct left ventricle, forming a left-right gradient. This suggests that Tbx5 expression was refined during evolution to pattern the ventricles. In support of this hypothesis, we show that loss of Tbx5 in the mouse ventricle results in a single chamber lacking distinct identity, indicating a requirement for Tbx5 in septation. Importantly, misexpression of Tbx5 throughout the developing myocardium to mimic the reptilian expression pattern also results in a single mispatterned ventricular chamber lacking septation. Thus ventricular septation is established by a steep and correctly positioned Tbx5 gradient. Our findings provide a molecular mechanism for the evolution of the amniote ventricle, and support the concept that altered expression of developmental regulators is a key mechanism of vertebrate evolution.

Early gene expression profiles during intraoperative myocardial ischemia-reperfusion in cardiac surgery.

OBJECTIVE: The effects of cold cardioplegic arrest and reperfusion on human ventricular gene expression are unknown. We tested the hypothesis that intraoperative ischemia-reperfusion under conditions of blood cardioplegic arrest would induce a unique myocardial genomic profile indicative of a cardioprotective response. METHODS: Right ventricular samples were serially acquired during surgical repair of ventricular septal defect. RESULTS: Expression profiling revealed 3 patterns of gene expression: (1) increased expression above control levels within 1 hour of cardioplegic arrest, with further amplification during early reperfusion; (2) increased expression limited to the reperfusion phase; and (3) reduced expression during reperfusion. Functional annotation and network mapping of differentially expressed genes indicated activation of multiple signaling pathways regulated by phosphatidylinositide 3'-OH kinase convergent on cellular growth and reparative programs. Also observed was increased expression of genes regulating hemoglobin synthesis, suggesting a novel cardioprotective pathway evoked during ischemia-reperfusion. CONCLUSION: Reversible myocardial ischemia-reperfusion during cardiac surgery is associated with an immediate genomic response that predicts a net cardioprotective phenotype.

Tbx5-dependent rheostatic control of cardiac gene expression and morphogenesis.

Dominant mutations in the T-box transcription factor gene TBX5 cause Holt-Oram syndrome (HOS), an inherited human disease characterized by upper limb malformations and congenital heart defects (CHDs) of variable severity. We hypothesize that minor alterations in the dosage of Tbx5 directly influences severity of CHDs. Using a mouse allelic series, we show a sensitive inverse correlation between Tbx5 dosage and abnormal cardiac morphogenesis and gene expression. The CHDs found in mice harbouring a hypomorphic allele of Tbx5 (Tbx5(lox/+) mice) are less pronounced than those found in Tbx5 haploinsufficient mice (Tbx5(del/+)), and homozygous hypomorphic (Tbx5(lox/lox)) embryos have noticeably more advanced cardiac development than Tbx5 null (Tbx5(del/del)) embryos. Examination of target gene expression across the allelic series uncovers very fine sensitivity across the range of Tbx5 dosages, in which some genes respond dramatically differently to only 15% differences in Tbx5 mRNA levels. This analysis was expanded to a genome-wide level, which uncovered a Tbx5 dosage-sensitive genetic program involving a network of cardiac transcription factors, developmentally important cell-cell signaling molecules, and ion channel proteins. These results indicate an exquisite sensitivity of the developing heart to Tbx5 dosage and provide significant insight into the transcriptional and cellular mechanisms that are disrupted in CHDs.

The remote ischemic preconditioning stimulus modifies gene expression in mouse myocardium.

BACKGROUND: We have recently demonstrated that remote ischemic preconditioning reduces ischemia-reperfusion injury in animal models. The mechanisms by which the remote ischemic preconditioning stimulus exerts its effect remain to be fully defined, and its effect on myocardial gene expression is unknown. We tested the hypothesis that remote ischemic preconditioning modifies myocardial gene expression immediately after the remote ischemic preconditioning stimulus (early phase) and 24 hours later (late phase). METHODS: Twenty male (C57BL/6) 10- to 12-week-old mice were randomized into 4 groups: group 1 (control, early phase; n = 5), group 2 (remote ischemic preconditioning, early phase; n = 5), group 3 (control, late phase; n = 5), and group 4 (remote ischemic preconditioning, late phase; n = 5). Groups 2 and 4 underwent remote ischemic preconditioning induced by 6 cycles of 4 minutes of occlusion and 4 minutes of reperfusion of the femoral artery. Groups 1 and 2 were killed 15 minutes after completion of sham procedure or remote ischemic preconditioning, and the hearts were removed and frozen in liquid nitrogen. Groups 3 and 4 were killed 24 hours after remote ischemic preconditioning, and the hearts were harvested in the same fashion. Gene expression was assessed by using the Affymetrix MG-430A chip (Affymetrix, Santa Clara, Calif). RESULTS: Data filtering (P < .05, analysis of variance) and hierarchic 2-way clustering identified significant differences in gene expression among the 4 groups. Genes involved in protection against oxidative stress (eg, Hadhsc, Prdx4, and Fabp4) and cytoprotection (Hsp73) were upregulated, whereas many proinflammatory genes (eg, Egr-1 and Dusp 1 and 6) were suppressed. CONCLUSION: A simple remote ischemic preconditioning stimulus modifies myocardial gene expression by upregulating cardioprotective genes and suppressing genes potentially involved in the pathogenesis of ischemia-reperfusion injury.

Tbx20 dose-dependently regulates transcription factor networks required for mouse heart and motoneuron development.

To elucidate the function of the T-box transcription factor Tbx20 in mammalian development, we generated a graded loss-of-function series by transgenic RNA interference in entirely embryonic stem cell-derived mouse embryos. Complete Tbx20 knockdown resulted in defects in heart formation, including hypoplasia of the outflow tract and right ventricle, which derive from the anterior heart field (AHF), and decreased expression of Nkx2-5 and Mef2c, transcription factors required for AHF formation. A mild knockdown led to persistent truncus arteriosus (unseptated outflow tract) and hypoplastic right ventricle, entities similar to human congenital heart defects, and demonstrated a critical requirement for Tbx20 in valve formation. Finally, an intermediate knockdown revealed a role for Tbx20 in motoneuron development, specifically in the regulation of the transcription factors Isl2 and Hb9, which are important for terminal differentiation of motoneurons. Tbx20 could activate promoters/enhancers of several genes in cultured cells, including the Mef2c AHF enhancer and the Nkx2-5 cardiac enhancer. The Mef2c AHF enhancer relies on Isl1- and Gata-binding sites. We identified a similar Isl1 binding site in the Nkx2-5 AHF enhancer, which in transgenic mouse embryos was essential for activity in a large part of the heart, including the outflow tract. Tbx20 synergized with Isl1 and Gata4 to activate both the Mef2c and Nkx2-5 enhancers, thus providing a unifying mechanism for gene activation by Tbx20 in the AHF. We conclude that Tbx20 is positioned at a critical node in transcription factor networks required for heart and motoneuron development where it dose-dependently regulates gene expression.

TBX5 mutations and congenital heart disease: Holt-Oram syndrome revealed.

PURPOSE OF REVIEW: Mutations in the T-box transcription factor TBX5 cause Holt-Oram syndrome (HOS), an autosomal-dominant condition characterized by a familial history of congenital heart defects and preaxial radial ray upper limb defects. This review summarizes recent developments in the study of TBX5 as it relates to congenital heart disease and the pathology of HOS. RECENT FINDINGS: Currently, 37 mutations in TBX5 have been found in patients with HOS. Most of these mutations cause premature truncation of the primary TBX5 transcript, thereby presumably causing haploinsufficiency. Conversely, missense mutations diminish the interaction of TBX5 with other transcription factors and reduce nuclear localization of mutant protein. Although mutations are found throughout the TBX5 gene, no evidence exists to suggest that genotype affects the location of heart and limb defects or the severity of HOS manifestation. However, genetic background, and to a lesser extent, environmental and stochastic modifiers are believed to influence greatly the severity of HOS manifestation and may account for the large variation seen in the severity of defects, even among members of the same kindred. Careful clinical examination of patients who seek treatment with heart and limb malformations is necessary to avoid misdiagnosis of similar congenital conditions. With the proper examination, TBX5 mutations can be identified in more than 70% of patients with a clinical diagnosis of HOS. SUMMARY: Genetic analysis of patient populations and the biochemical characterization of the mutated proteins have provided considerable insight into the function of TBX5 in cardiac development and disease pathology. Novel discoveries await as these two paradigms merge.