Abnormal control of lung branching in experimental esophageal atresia

Purpose

Esophageal atresia and tracheo-esophageal fistula (EA-TEF) result from abnormal division of the foregut into esophagus and trachea thus, it may influence airway branching and lung development. The present study examined lung morphogenesis in fetuses with EA-TEF focusing in the expression of FGF10 and its receptor FGFR2 IIIb.

Methods

Pregnant rats received either 1.75 mg/kg i.p. adriamycin or vehicle on E7, E8 and E9. Embryos were recovered at E15, E18 and E21 and lungs processed for immunohistochemistry and RT-PCR. Three groups were studied: control, adriamycin-exposed with EA-TEF, and adriamycin-exposed without EA-TEF. Comparisons were performed with Mann–Whitney or t tests (significance level, 5 %).

Results

Lung weight at E15 and E18 were significantly lower in adriaEA fetuses in which the relative mRNA levels of FGF10 were significantly higher. These differences disappeared near term. The receptor FGFR2 IIIb messenger was only significantly increased in adria noEA fetuses at E15. Immunohistochemical study was consistent with these findings.

Conclusions

Abnormal expression of FGF10 during earlier stages of development, when the lungs are smaller than controls, suggests a compensatory response aimed at “catching up” delayed tracheobronchial branching. Whether similar changes take place in the human condition and influence respiratory physiology remain to be determined.     

Altered Tbx1 gene expression is associated with abnormal oesophageal development in the adriamycin mouse model of oesophageal atresia/tracheo-oesophageal fistula

Introduction

Oesophageal atresia/tracheo-oesophageal atresia (OA/TOF) frequently arises with associated anomalies and has been clinically linked with 22q11 deletion syndromes, a group of conditions due to Tbx1 gene mutation which include Di George syndrome. Tbx1 and Tbx2 genes modulate pharyngeal and cardiac development, but are also expressed in the developing foregut and are known to interact with key signalling pathways described in oesophageal formation including bone morphogenic proteins. The adriamycin mouse model (AMM) reliably displays OA/TOF-like foregut malformations providing a powerful system for investigating the disturbances in gene regulation and morphology involved in tracheo-oesophageal malformations. We hypothesised that foregut abnormalities observed in the AMM are associated with altered Tbx1 and Tbx2 gene expression.

Methods

Time-mated CBA/Ca mice received intra-peritoneal injection of adriamycin (for treated) or saline (for controls) on embryonic days (E)7 and 8. Untreated Cd1 embryos were used to establish normal expression patterns. Embryos harvested on E9–E11 underwent whole-mount in situ hybridization with labelled RNA probes for Tbx1 and Tbx2. Optical projection tomography was used to visualise expression in whole embryos by 3D imaging.

Results

Tbx1 expression was visualised in a highly specific pattern in the proximal oesophageal endoderm in normal and control embryos. In the AMM, extensive ectopic expression of Tbx1 was detected in the dorsal foregut and adjacent to the TOF. The focally restricted oesophageal expression pattern persisted in the AMM, but was posteriorly displaced in relation to the tracheal bifurcation. Tbx2 was widely expressed in the ventral foregut mesoderm of controls, lacking specific endoderm localisation. In the AMM, altered Tbx2 expression in the foregut was only seen in severely affected embryos.

Conclusion

Highly specific Tbx1 expression in the proximal oesophageal endoderm suggests that Tbx1 may be an important regulator of normal oesophageal development. Altered Tbx1 expression in dorsal foregut and adjacent to the TOF in the AMM suggests that Tbx1 gene disruption may contribute to the pathogenesis of tracheo-oesophageal malformations.     

Upregulation of Endothelin Receptors A and B in the nitrofen induced hypoplastic lung occurs early in gestation

Purpose

Pulmonary hypoplasia and persistent pulmonary hypertension (PPH) aggravate clinical courses in congenital diaphragmatic hernia (CDH). Endothelin 1 enhances PPH by vasoconstriction and proliferation of vessel walls. Up-regulation of pulmonary Endothelin Receptors A and B (EDNRA, EDNRB) has been reported in human CDH and animal models, but the onset of those alterations during lung development remains unclear. We hypothesized that pulmonary expression of EDNRA and EDNRB is up-regulated at early gestational stages in the nitrofen model.

Methods

Pregnant rats were exposed to nitrofen or vehicle on gestational day 9 (D9). Embryos were sacrificed on D15, D18 and D21 and divided into nitrofen- and control group. Pulmonary RNA was extracted and mRNA levels of EDNRA and EDNRB were determined by real-time PCR. Immunohistochemistry for protein expression of both receptors was performed.

Results

mRNA levels of EDNRA and EDNRB were significantly increased in the nitrofen group on D15, D18 and D21. Immunohistochemistry revealed increased pulmonary vascular expression of EDNRA and EDNRB compared to controls.

Conclusion

Altered expression of EDNRA and EDNRB is an early event in lung morphogenesis in the nitrofen model. We speculate that pulmonary arteries in CDH become excessively muscularised in early fetal life, becoming unable to adapt normally at birth.     

先天性食管闭锁并气管食管瘘的早期胚胎学研究

目的利用阿霉素诱导制作食管闭锁并气管食管瘘（esophageal atresia and tracheoesophageal fistula，EA-TEF）大鼠模型，探讨胚胎发育中气管、食管分化异常的发生机制及可能的影响因素。方法明确孕龄的SD雌性孕鼠9只，随机分为正常组2只及模型组7只，模型组于E6～E9d每日腹腔注射2mg／kg阿霉素，正常组不注射。正常组于E11．5、E12．5d，模型组于E11．5、E12．5、E13．5d取材。进行HE及PAS染色，成纤维细胞生长因子7、10（fibroblast growth factor7，FGF7，10）免疫组化染色。留1只模型组孕鼠于E21d处死，体式镜下解剖。结果①正常对照组：HE染色可见到11．5d肺芽萌出，12．5d时可见气管、食管分离，在气管、食管分离处的前肠壁内有大量的凋亡小体。PAS染色及FGF7、10免疫组化染色可见前肠背侧半及食管为阴性，前肠腹侧半及气管部分为阳性；②模型组：HE染色11．5d未见明显肺芽萌出，12．5d可见瘘管与两侧支气管类似三分叉结构，在几乎相同水平发出。PAS染色及FGF7、10免疫组化染色可见瘘管组织阳性染色，近段前肠可见喉气管憩室以远的腹侧半为阳性。结论对正常大鼠及阿霉素致畸动物模型早期胚胎学的观察得出以下结论：①正常气管、食管的分隔可能与局部细胞的凋亡有关；②气管、食管的正常分隔可能为前肠正常发育的必要条件；③FGF7、10在模型组TEF中表达，表明可能存在间充质细胞的异常，产生异常的信号因子导致TEF。     

Downregulation of p300 gene expression in airway mesenchyme of nitrofen-induced hypoplastic lungs

Purpose

Congenital diaphragmatic hernia (CDH) is a relatively common developmental abnormality causing life-threatening respiratory distress at birth. The nitrofen model has been widely used to investigate the pathogenesis of hypoplastic lungs associated with CDH. Embryos lacking p300 and CBP genes are significantly smaller in lung formation. We hypothesized that pulmonary gene expression of p300 and CBP is downregulated during late gestation in the nitrofen-induced CDH model.

Methods

Time-pregnant rats were treated with either nitrofen or vehicle on gestational day 9 (D9). Fetal lungs were harvested on D18 and D21 (n = 8 at each time point). Pulmonary gene expression of p300 and CBP was analyzed by quantitative real-time PCR. Immunohistochemistry was performed to investigate expression and localization of pulmonary p300 and CBP proteins.

Results

Relative mRNA expression levels of p300 were significantly decreased in nitrofen-induced hypoplastic lungs on D18 compared to controls (3.00 ± 0.20 vs. 3.76 ± 0.14; p = 0.0039), while CBP levels were not altered. p300 immunoreactivity was markedly diminished in surrounding mesenchymal compartments and nuclei of proximal and distal airway cells, while CBP expression was not altered.

Conclusion

Downregulation of p300 gene expression during the early canalicular stage may disrupt epithelial–mesenchymal signaling interactions, contributing to the development of hypoplastic lungs in the nitrofen-induced CDH model.     

Maternal hyperthyroidism increases the prevalence of foregut atresias in fetal rats exposed to adriamycin

Purpose

Gastrointestinal malformations such as esophageal atresia with tracheoesophageal fistula (EA/TEF) and duodenal atresia (DA) have been reported in infants born to hyperthyroid mothers or with congenital hypothyroidism. The present study aimed to test whether maternal thyroid status during embryonic foregut division has any influence on the prevalence of EA/TEF and DA in an accepted rat model of these malformations.

Methods

Pregnant rats received either vehicle or 1.75 mg/kg i.p. adriamycin on gestational days 7, 8 and 9. Transient maternal hyper or hypothyroidism was induced by oral administration of levothyroxine (LT₄, 50 μg/kg/day) or propylthiouracil (PTU, 2 mg/kg/day), respectively, on days 7 to 12 of gestation. Plasma cholesterol, total T₃, free T₄ and TSH were measured at gestational days 7, 12, and 21. At the end of gestation, the mothers were sacrificed and embryo–fetal mortality was recorded. Fetuses were dissected to determine the prevalence of esophageal and intestinal atresias.

Results

At gestational day 12, mothers treated with LT₄ or PTU had hyper or hypothyroid status, respectively; plasma cholesterol levels were similar. In the adriamycin-exposed fetuses from hyperthyroid mothers, the embryonal resorption rate and the prevalence of both EA/TEF and DA were significantly higher than in the other groups; maternal hypothyroidism during the same period did not have significant effect on the prevalence of atresias.

Conclusions

Maternal hyperthyroidism during the embryonic window corresponding to foregut cleavage increased the prevalence of both EA/TEF and duodenal atresia in fetal rats exposed to adriamycin. This suggests that maternal thyroid hormone status might be involved in the pathogenesis of foregut atresias and invites further research on this likely clinically relevant issue in humans.     

Cell death in the early adriamycin rat model

The adriamycin rat model (ARM) exhibits many features of the VACTERL association. Adriamycin is a cytotoxic drug used in cancer chemotherapy. Although its exact mode of action is not clear, it is presumed to have a similar cytotoxic role in the developing embryo. Lysotracker red (LT) is a dye that stains phagolysosomes and apoptotic bodies and allows entire rodent embryos to be stained for apoptosis. We hypothesised that there was increased cell death in adriamycin-exposed embryos. To investigate this hypothesis, adriamycin (1.75 mg/kg) was given intraperitoneally to rats on days 7, 8, and 9 of pregnancy. A control group was given saline on the same schedule. Embryos were recovered at 3, 12, 24, and 48 h following the last dose and also at term (21 days) to confirm that the usual incidence of congenital anomalies found in the ARM was obtained in our animal model. Embryos were embedded in resin, sectioned, and studied by light microscopy. Embryos from the 3-h and 24-h groups were studied using LT and confocal microscopy to search for evidence of apoptosis. All term newborns (100%) from the adriamycin-treated group demonstrated the typical abnormalities found in the ARM, i.e., oesophageal atresia, multiple gastrointestinal atresias, vertebral malformations, absent tails, ureterohydronephrosis, etc. In the 9.5-day adriamycin group there was no difference in appearance between the experimental and control embryos. Specifically, no cellular debris or increased cell turnover indicative of adriamycin cytotoxicity was observed in the experimental group. At day 10.5, 90% of embryos from two separate litters had evidence of notochordal distortion and tethering to the gut or gut-tube abnormalities. These findings were not observed in the control embryos. Confocal microscopy and LT examination of the embryos from litters killed at 3 and 24 h following the last dose of adriamycin demonstrated no evidence of increased cell death in adriamycin-exposed embryos compared to control embryos. The absence of significant apoptosis in the developing embryos in the immediate period following administration of adriamycin suggests that the teratogenic effect of adriamycin is not caused by cell death.     

Downregulation of insulin-like growth factor binding protein 3 and 5 in nitrofen-induced pulmonary hypoplasia

Purpose

The high mortality in congenital diaphragmatic hernia (CDH) is mainly attributed to pulmonary hypoplasia. Recent studies suggest that retinoid signaling pathway (RSP) is inhibited in the nitrofen-induced hypoplastic lung. The insulin-like growth factor (IGF) system plays a crucial role in fetal lung development by interaction of IGFBP-3 and IGFBP-5 with RSP. We hypothesized that pulmonary IGFBP-3 and IGFBP-5 gene expression levels are downregulated in the nitrofen-induced pulmonary hypoplasia.

Methods

Pregnant rats were exposed to either olive oil or 100 mg nitrofen on day 9.5 (D9.5) of gestation. Fetal lungs were harvested on D18 and D21 and divided into control and nitrofen groups. IGFBP-3 and IGFBP-5 pulmonary gene and protein expression were determined using real-time RT–PCR and immunohistochemistry.

Results

Relative levels of IGFBP-3 mRNA were significantly decreased in the nitrofen group (8.00 ± 14.44) in D21 compared to controls (14.81 ± 16.11; p < 0.05). Expression levels of IGFBP-5 mRNA were also significantly decreased in nitrofen group (10.66 ± 4.83) on D18 compared to controls (17.92 ± 4.77). Immunohistochemistry showed decreased IGFBP-3 expression on D21 and decreased IGFBP-5 immunoreactivity on D18 in hypoplastic lungs compared to controls.

Conclusion

Downregulation of IGFBP-3 and IGFBP-5 gene expression may cause pulmonary hypoplasia in the nitrofen-induced CDH model by interfering with retinoid signaling pathway.     

Free-breathing cine CT for the diagnosis of tracheomalacia in young children

Background

Tracheomalacia is characterized by excessive expiratory collapse of the trachea.

Objective

To investigate the accuracy of free-breathing cine CT for diagnosis of tracheomalacia in young children with bronchoscopy as reference standard.

Materials and methods

In a retrospective study (May 2001–July 2008), a patient group (n?=?27) of children with bronchoscopic evidence of tracheomalacia, and a control group (n?=?320) underwent free-breathing cine CT. The tracheal shape on free-breathing cine CT was classified as round, lunate, elongated or crescentic. Cross-sectional area change of the trachea and age were compared between the groups and the diagnostic performance of free-breathing cine CT for tracheomalacia was evaluated.

Results

The patient group showed significantly greater cross-sectional area change of the trachea (57.2%?±?22.2% vs. 10.6%?±?11.2%, P?<?0.001) than the control group. If a cross-sectional area change of the trachea of 31.6% was used as a cut-off value for the diagnosis of tracheomalacia, the sensitivity, specificity and accuracy of cine CT were 96.3% (26/27), 97.2% (311/320) and 97.1% (337/347), respectively. If a crescentic shape during the expiratory phase was used, the sensitivity, specificity and accuracy were 51.9% (14/27), 98.8% (316/320) and 95.1% (330/347), respectively.

Conclusion

Free-breathing cine CT has potential to provide the diagnosis of tracheomalacia in young children.     

Disturbance of parathyroid hormone-related protein signaling in the nitrofen-induced hypoplastic lung

Purpose

Despite remarkable progress in resuscitation and intensive care, the morbidity and mortality rates in congenital diaphragmatic hernia (CDH) remain high due to severe pulmonary hypoplasia. The pathogenesis of pulmonary hypoplasia associated with CDH is still not clearly understood. Pulmonary parathyroid hormone-related protein (PTHrP) is expressed in the type II epithelial cells and stimulates surfactant production by a paracrine feedback loop regulated by PTHrP receptor (PTHrP-R), which is expressed in the mesenchyme, during terminal airway differentiation. It has been reported that PTHrP knockout and PTHrP-R null mice both exhibit pulmonary hypoplasia, disrupting alveolar maturation before birth. We designed this study to test the hypothesis that gene expression of PTHrP and PTHrP-R is downregulated in the late stages of lung morphogenesis in the nitrofen-induced hypoplastic lung.

Methods

Pregnant rats were exposed to either olive oil or nitrofen on day 9 of gestation (D9). Fetal lungs were harvested on D15, 18, and 21 and divided into three groups: control, nitrofen without CDH [CDH(?)], and nitrofen with CDH [CDH(+)] (n = 8 at each time point for each group, respectively). Total mRNA was extracted from fetal lungs and mRNA expression of PTHrP and PTHrP-R was analyzed by real-time RT-PCR and the significant differences between the groups were accepted at P < 0.05 by statistical analysis. Immunohistochemical studies were also performed to evaluate PTHrP and PTHrP-R protein expression at each time point.

Results

Pulmonary mRNA expression of PTHrP-R was significantly decreased in both nitrofen groups [CDH(?) and CDH(+)] compared to controls at D18 and 21. The mRNA level of PTHrP was significantly decreased at D21 in both nitrofen groups compared to controls. Immunoreactivity of PTHrP and PTHrP-R at D18 and 21 was diminished in the distal epithelium and in the mesenchyme, respectively, in the nitrofen-induced hypoplastic lung compared to control lungs. There were no significant differences in both gene/protein expression of PTHrP and PTHrP-R on D15.

Conclusion

Downregulation of PTHrP and PTHrP-R gene expression during late lung morphogenesis may cause pulmonary hypoplasia in the nitrofen CDH model, disrupting alveolar maturation and surfactant production by interfering with mesenchymal–epithelial interactions.     

Anorectal neural crest derived cell behavior after the migration of vagal neural crest derived cells is surgically disrupted: implications for the etiology of Hirschsprung’s disease

Background/purpose

In Hirschsprung’s disease (HD), thick extrinsic nerve fibers can be associated with the aganglionic segment in the anorectum. We surgically disrupted the migration of vagal neural crest cell-derived cells (vagal NCC) in embryos from transgenic mice we created previously (SOX10-VENUS Tg) which have the SOX10 gene labeled with Venus (V), a green fluorescent protein, to observe sacral NCC activity in the anorectum.

Method

Proximal colon harvested from SOX10-VENUS Tg embryos on day 10.5 (n = 10) was transected at the ascending colon. V-positive sacral NCC in the anorectum were observed during organ culture under fluorescence stereoscopic microscopy, and compared with non-transected control specimens (n = 10).

Results

In transected specimens, no V-positive sacral NCC were identified initially in the anorectum. By day 2, there were thick beaded sacral NCC in the anorectum in 6/10 (60 %) that migrated steadily to the transected end over 3–4 days. In controls, thinner and shorter V-positive sacral NCC began migrating cranially on day 2, and were met by distally migrating vagal NCC.

Conclusion

Disruption of vagal NCC migration appears to induce sacral NCC activity in the anorectum, suggesting that thick extrinsic nerve fibers seen in HD may be a secondary phenomenon.     

Transition von jungen Frauen mit Ullrich-Turner-Syndrom in die Erwachsenenmedizin

Introduction

Turner syndrome (TS) is a genetic disorder associated with a complete or partial absence of X chromosomes. Children and adult patients with TS have multiple comorbidities including a wide spectrum of metabolic, cardiovascular, renal, gastrointestinal abnormalities and also psychosocial problems. During childhood, patients have been traditionally treated in pediatric outpatient clinics, whereas appropriate care during the transition phase and thereafter seems to be missing.

Methods

For the purpose of this article a literature review was conducted of the most recent recommendations regarding the evaluation and treatment of girls and women with TS, with a focus on the transition phase. The experience of an interdisciplinary panel of experts is additionally reported.

Results

After analyzing the available publications the lack of a clear aftercare concept, the uncertainty of some general practitioners and also the absence of disease awareness in some patients are evident.

Discussion

The comorbidities of adult patients with TS include a wide spectrum of metabolic, cardiovascular, renal, gastrointestinal abnormalities, endocrine and gynecological disturbances and also psychosocial problems. Additionally, a long-term treatment by hormone substitution, e.g. estrogen gestagen replacement by specialists is indicated. We recommend performing a detailed diagnostic evaluation at the time of transition and also every 1–5 years depending on the risk profile and symptoms of each patient.     

Cardiac diagnostics before oral propranolol therapy in infantile hemangioma: retrospective evaluation of 234 infants

Background

The indication and extent of cardiac screening before oral propranolol therapy (OPT) in patients with infantile hemangioma (IH) has been challenged. In this study, we evaluated pre-OPT cardiac diagnostics in a pediatric IH cohort in our department.

Methods

Retrospective chart review of infants ≤ 12 months old with IH undergoing OPT. The diagnostics prior to OPT, occurrence of complications, and outcome were recorded.

Results

A total of 234 patients were evaluated. The mean age at the onset of OPT was 4.2 ± 0.3 months, the average duration of OPT was 6.1 ± 0.1 months, and the average follow-up was 12.3 ± 0.7 months. Echocardiograms and electrocardiograms were performed prior to OPT in all patients. One hundred and three (44.0%) echocardiograms revealed pathological findings, 19 (8.1%) of which were minor (including atrial septal defects, pulmonary stenosis, and patent ductus arteriosus). Pathological findings were observed in 17 (7.3%) of electrocardiograms, only one (0.4%) of which was minor (suspected cardiac arrhythmia, subsequently excluded by long-term electrocardiogram analysis). These findings did not contraindicate OPT and no severe adverse events associated with OPT occurred during the follow-up period.

Conclusions

Routine cardiac screening by electrocardiogram and echocardiogram before OPT is debatable and not routinely indicated in children with IH. Further studies are necessary to draw definite conclusions on the reasonable indication and extent of this diagnostic approach.

     

Decreased pulmonary c-Cbl expression and tyrosine phosphorylation in the nitrofen-induced rat model of congenital diaphragmatic hernia

Purpose

The high morbidity of newborn infants with congenital diaphragmatic hernia (CDH) is attributed to pulmonary hypoplasia (PH), which is characterized by a failure of alveolar development. The nitrofen-induced CDH model has been widely used to investigate the pathogenesis of PH in CDH. It has previously been shown that the fibroblast growth factor receptor (FGFR) pathway, which is essential for a proper lung development, is disrupted during late gestation of nitrofen-induced CDH. Casitas B-lineage lymphoma (c-Cbl) proteins are known regulators of signal transduction through FGFRs, indicating their important role during alveolarization in developing lungs. Furthermore, it has been demonstrated that tyrosine phosphorylation of c-Cbl proteins has a pivotal role for their physiological function and activity during fetal lung development. We designed this study to test the hypothesis that pulmonary c-Cbl expression and tyrosine phosphorylation status are decreased in the nitrofen-induced CDH model.

Methods

Timed-pregnant rats received either 100 mg nitrofen or vehicle on gestation day 9 (D9). Fetuses were harvested on D18 and D21, and lungs were divided into two groups: control and hypoplastic lungs with CDH (CDH⁺) (n = 10 at each time-point, respectively). Pulmonary gene expression levels of c-Cbl were analyzed by quantitative real-time polymerase chain reaction. Western blotting combined with densitometry analysis was used for semi-quantification of protein levels of pulmonary c-Cbl and tyrosine phosphorylation status. Confocal-immunofluorescence staining was performed to evaluate c-Cbl protein expression and distribution.

Results

Relative mRNA expression levels of pulmonary c-Cbl were significantly decreased in CDH⁺ on D18 and D21 compared to controls. Western blotting showed markedly decreased protein levels of pulmonary c-Cbl and tyrosine phosphorylation status in CDH⁺ on D18 and D21. Confocal-immunofluorescence analysis confirmed decreased c-Cbl expression in CDH⁺ on D18 and D21 mainly in the distal alveolar epithelium compared to controls.

Conclusion

Decreased pulmonary c-Cbl gene and protein expression accompanied by a decreased tyrosine phosphorylation status during the late stages of fetal lung development may result in reduced c-Cbl activity, and thus interfere with the FGFR-mediated alveolarization in the nitrofen-induced CDH model.     

Pulmonary FGF-18 gene expression is downregulated during the canalicular-saccular stages in nitrofen-induced hypoplastic lungs

Purpose

Pulmonary hypoplasia (PH) associated with congenital diaphragmatic hernia (CDH) represents one of the major challenges in neonatal intensive care. However, the molecular pathogenesis of PH is still poorly understood. In developing fetal lungs, fibroblast growth factor 18 (FGF-18) plays a crucial role in distal airway maturation. FGF-18 knockouts show smaller lung sizes with reduced alveolar spaces and thicker interstitial mesenchymal compartments, highlighting its important function for fetal lung growth and differentiation. We hypothesized that pulmonary FGF-18 gene expression is downregulated during late gestation in nitrofen-induced hypoplastic lungs.

Methods

Pregnant rats were exposed to either olive oil or nitrofen on day 9 of gestation (D9). Fetuses were harvested on D18 and D21, and lungs were divided into three groups: controls, hypoplastic lungs without CDH [CDH(?)], and hypoplastic lungs with CDH [CDH(+)] (n = 24 at each time-point). Pulmonary FGF-18 gene expression levels were analyzed by qRT-PCR. Immunohistochemistry was performed to investigate FGF-18 protein expression/distribution.

Results

Relative mRNA levels of pulmonary FGF-18 gene expression were significantly decreased in CDH(?) and CDH(+) on D18 and D21 compared to controls (p < 0.05 and p < 0.01, respectively). Immunoreactivity of FGF-18 was markedly diminished in mesenchymal cells surrounding the airway epithelium on D18 and D21 compared to controls.

Conclusion

Downregulation of FGF-18 gene expression in nitrofen-induced hypoplastic lungs suggests that decreased FGF-18 expression during the canalicular–saccular stages may interfere with saccular–alveolar differentiation and distal airway maturation resulting in PH.     

Innominate artery transection for patients with severe chest deformity: optimal indication and timing

Purpose

The innominate artery sometimes compresses the trachea, leading to tracheomalacia and highly fatal tracheoinnominate fistula in patients with severe chest deformity. This study is focused on the indication of innominate artery transection for the definitive treatment of these complications.

Patients and methods

We retrospectively analyzed the medical records of eight patients who underwent transection of innominate artery.

Results

All patients had developed severe chest deformity and their symptoms were life-threatening anoxic spell or endotracheal hemorrhage. Bronchoscopy showed tracheomalacia with or without pulsatile granulations on the anterior wall of the trachea underlying the innominate artery. In six cases who had previously undergone tracheostomy or laryngotracheal separation, the tracheal tube tip made granulations or tracheoinnominate fistulas. In addition to transection of innominate artery, the tracheoinnominate fistula was closed in two cases and the artery was transposed in one. All patients survived without neurologic complications and airway symptoms postoperatively.

Conclusions

For patients with severe chest deformity, innominate artery transection is indicated when they have tracheal compression by the artery and need to be intubated through the compressed part of trachea to secure the airway. This would be the best timing to schedule the prophylactic operation.     

Evidence for decreased lipofibroblast expression in hypoplastic rat lungs with congenital diaphragmatic hernia

Purpose

Pulmonary hypoplasia (PH) is a serious condition in newborns with congenital diaphragmatic hernia (CDH). Lipid-containing interstitial fibroblasts (LIFs) play an essential role in fetal lung maturation by stimulating alveolarization and lipid homeostasis. In rodents, LIFs are first evident during the canalicular phase of lung development with a significant increase over the last 4 days of gestation. Adipocyte differentiation-related protein (ADRP), a functional lipogenic molecular marker characterizing LIFs, is highly expressed in fetal lungs during this critical time period. We hypothesized that LIF expression in hypoplastic rat lungs is decreased in the nitrofen-induced CDH model, which is accompanied by reduced alveolar ADRP expression and lipid content.

Methods

On embryonic day 9.5 (E9.5), time-mated rats received either nitrofen or vehicle. Fetuses were sacrificed on selected time points E18.5 and E21.5, and dissected lungs were divided into controls and CDH-associated PH. Pulmonary gene expression levels of ADRP were determined by quantitative real-time polymerase chain reaction. ADRP immunohistochemistry and oil red O staining were used to assess pulmonary protein expression and lipid content. Immunofluorescence double staining for alpha smooth muscle actin, which is known to be absent in LIFs, and lipid droplets was performed to evaluate the pulmonary expression of this specific subset of fibroblasts.

Results

Relative mRNA expression of ADRP was significantly reduced in lungs of CDH-associated PH on E18.5 and E21.5 compared to controls. ADRP immunoreactivity and lipid staining were markedly diminished in alveolar mesenchymal cells of CDH-associated PH on E18.5 and E21.5 compared to controls. Confocal laser scanning microscopy demonstrated markedly decreased LIF expression in alveolar interstitium of CDH-associated PH on E18.5 and E21.5 compared to controls.

Conclusion

Decreased pulmonary LIF expression during late gestation suggests impaired LIF functioning in the nitrofen-induced CDH model, which may cause disruption in fetal alveolarization and lipid homeostasis, and thus contribute to the development of PH.