Appendiceal Carcinoids in Children-Prevalence, Treatment and Outcome in a Large Nationwide Pediatric Cohort.

Background and Objectives: Appendiceal carcinoids are rare neuroendocrine tumors and mainly found incidentally during histopathological examination following appendectomy. This observational cohort study was performed to determine the prevalence, treatment modalities and outcomes in children diagnosed with an appendiceal carcinoid tumor. Materials and Methods: Data from the largest German statutory health insurance "Techniker Krankenkasse" were analyzed within an 8-year period: January 2010 to December 2012 and January 2016 to December 2020. Patient characteristics, surgical technique, type of surgical department, diagnostic management, and postoperative morbidity were analyzed. Results: Out of 40.499 patients following appendectomy, appendiceal carcinoids were found in 44 children, resulting in a prevalence of 0.11%. Mean age at appendectomy was 14.7 (±2.6) years. Laparoscopic approach was performed in 40 (91%) cases. Right-sided hemicolectomy was performed in 8 (18%) patients. Additional diagnostic work-up (CT and MRI) was recorded in 5 (11%) children. Conclusions: This large nationwide pediatric study shows that 1 in 1000 patients was found to have a neuroendocrine tumor of the appendix (prevalence 0.11%), emphasizing its low prevalence in the pediatric age group. The majority of patients were treated with appendectomy only. However, treatment modalities are still variable. Longer follow-up analyses are needed to evaluate published guidelines and recommendations to aim for a limited surgical approach.

Disruption of copper-dependent signaling pathway in the nitrofen-induced congenital diaphragmatic hernia.

BACKGROUND: Normal development of the fetal diaphragm requires muscularization of the diaphragm as well as the structural integrity of its underlying connective tissue components. Developmental mutations that inhibit the formation of extracellular matrix (ECM) have been shown to result in congenital diaphragmatic hernia (CDH). Copper (Cu) is an important element during diaphragm morphogenesis by participating in cross-linking of collagen and elastin fibers. Cu transport is strictly regulated by two membrane proteins: Cu-uptake transporter 1 (CTR1) and the Cu-efflux pump ATP7A. Animals lacking Cu-dependent enzymes exhibit abnormal connective tissue with diaphragmatic defects. However, the molecular basis of disruptions in Cu-mediated ECM formation in CDH remains unclear. We designed this study to investigate the hypothesis that diaphragmatic expression of CTR1 and ATP7A is decreased in the nitrofen-induced CDH model. METHODS: Timed-pregnant rats were exposed to either nitrofen or vehicle on gestational day 9 (D9), and fetuses were harvested on selected time-points D15 and D18. Microdissected fetal diaphragms (n = 48) were divided into control and nitrofen-induced CDH samples (n = 12 per experimental group and time-point). Diaphragmatic gene expression levels of CTR1 and ATP7A were analyzed by quantitative real-time polymerase chain reaction. Immunohistochemistry was performed to evaluate CTR1 and ATP7A protein expression in fetal diaphragms, which was combined with specific rhodanine staining to determine diaphragmatic Cu content. RESULTS: Relative mRNA levels of CTR1 and ATP7A were significantly reduced in diaphragms of nitrofen-exposed fetuses on D15 (0.06 ± 0.02 vs. 0.18 ± 0.08; p < 0.05 and 0.04 ± 0.02 vs. 0.08 ± 0.02; p < 0.05) and D18 (0.10 ± 0.03 vs. 0.17 ± 0.02; p < 0.05 and 0.09 ± 0.03 vs. 0.16 ± 0.04; p < 0.05) compared to controls. Immunoreactivity of CTR1 and ATP7A was markedly decreased in the malformed diaphragmatic ECM of nitrofen-exposed fetuses on D15 and D18, which was associated with a significantly decreased diaphragmatic Cu content on D15 (7.22 ± 2.91 vs. 17.50 ± 3.09; p < 0.05) and D18 (17.60 ± 3.54 vs. 28.20 ± 4.63; p < 0.05) compared to controls. CONCLUSION: Reduced diaphragmatic expression of CTR1 and ATP7A during morphogenesis may impair the activity of Cu-dependent enzymes and thus contribute to defective ECM during diaphragmatic development.

Myogenin gene expression is not altered in the developing diaphragm of nitrofen-induced congenital diaphragmatic hernia.

PURPOSE: Pleuroperitoneal folds (PPFs) represent the only source of muscle precursors cells (MPCs) in the primordial diaphragm. However, the exact pathogenesis of malformed PPFs and congenital diaphragmatic hernia (CDH) remains unclear. The muscle-specific transcription factor myogenin plays a key role during development and muscularization of the fetal diaphragm. Although myogenin knockout mice lack skeletal muscle fibers, the diaphragmatic musculature is intact without any defects. It has further been demonstrated that proliferation and differentiation of MPCs in PPFs and developing diaphragms are normal in rodent CDH models. We hypothesized that myogenin gene expression is not altered in malformed PPFs, developing diaphragms and diaphragmatic musculature in the nitrofen-induced CDH model. METHODS: Pregnant rats were exposed to nitrofen or vehicle on gestational day 9 (D9). Fetuses were harvested during PPF formation (D13), diaphragmatic development (D14-15) and muscularization (D18-21). Fetal PPFs, developing diaphragms and diaphragmatic musculature were dissected and divided into nitrofen and control groups. Myogenin mRNA levels were analyzed by quantitative real-time polymerase chain reaction, while immunohistochemistry was performed to investigate myogenin protein expression and distribution. RESULTS: Relative mRNA expression of myogenin was not significant different in PPFs (0.30 ± 0.09 vs. 0.48 ± 0.09; P = 0.37), developing diaphragms (1.25 ± 0.29 vs. 1.60 ± 0.32; P=0.53) and diaphragmatic musculature (1.08 ± 0.24 vs. 1.59 ± 0.20; P = 0.15) of nitrofen-exposed fetuses compared to controls. Myogenin immunoreactivity was not altered in the muscular components of malformed PPFs, developing diaphragms and diaphragmatic musculature of nitrofen-exposed fetuses compared to controls. CONCLUSION: Myogenin gene expression is not altered in PPFs, developing diaphragms and diaphragmatic musculature in the nitrofen-induced CDH model, thus suggesting that diaphragmatic defects in this model develop independent of myogenic processes.

Disruption of THY-1 signaling in alveolar lipofibroblasts in experimentally induced congenital diaphragmatic hernia.

PURPOSE: Pulmonary hypoplasia (PH), characterized by alveolar immaturity, remains the main cause of neonatal mortality and long-term morbidity in infants with congenital diaphragmatic hernia (CDH). Lipid-containing interstitial fibroblasts (LIFs) are critically important for normal alveolar development. Thymocyte antigen 1 (Thy-1) is a highly expressed cell-surface protein in this specific subset of lung fibroblasts, which plays a key role in fetal alveolarization by coordinating the differentiation and lipid homeostasis of alveolar LIFs. Thy-1 increases the lipid content of LIFs by upregulation of adipocyte differentiation-related protein (ADRP), a lipogenic molecular marker characterizing pulmonary LIFs. Thy-1 (-/-) mice further show impaired alveolar development with reduced proliferation of pulmonary LIFs, resulting in a PH-similar phenotype. We hypothesized that pulmonary Thy-1 signaling is disrupted in experimentally induced CDH, which may has an adverse effect on the lipid content of alveolar LIFs. METHODS: Timed-pregnant Sprague-Dawley rats were treated with either 100 mg nitrofen or vehicle on embryonic day 9.5 (E9.5). Fetuses were killed on E21.5, and lungs were divided into controls (n = 14) and CDH-associated PH (n = 14). Pulmonary gene expression levels of Thy-1 and ADRP were assessed by quantitative real-time PCR. ADRP immunohistochemistry and oil-red-O staining were used to localize alveolar LIF expression and lipid droplets. Immunofluorescence double staining for Thy-1 and oil-red-O was performed to evaluate Thy-1 expression and lipid content in alveolar LIFs. RESULTS: Radial alveolar count was significantly reduced in CDH-associated PH with significant downregulation of pulmonary Thy-1 and ADRP mRNA expression compared to controls. ADRP immunoreactivity and lipid droplets were markedly diminished in alveolar interstitial cells, which coincided with decreased alveolar LIF expression in CDH-associated PH compared to controls. Confocal laser scanning microscopy confirmed markedly decreased Thy-1 expression and lipid content in alveolar LIFs of CDH-associated PH compared to controls. CONCLUSION: Our study provides strong evidence that disruption of pulmonary Thy-1 signaling results in reduced lipid droplets in alveolar LIFs and may thus contribute to PH in the nitrofen-induced CDH model. Treatment modalities aimed at increasing lipid content in alveolar LIFs may therefore have a therapeutic potential in attenuating CDH-associated PH.

Prenatal administration of all-trans retinoic acid upregulates leptin signaling in hypoplastic rat lungs with experimental congenital diaphragmatic hernia.

PURPOSE: Pulmonary hypoplasia (PH), characterized by alveolar immaturity, is one of the leading causes of respiratory insufficiency in newborns with congenital diaphragmatic hernia (CDH). Leptin (Lep) and its receptor (Lep-R) play an important role in fetal lung growth by stimulating alveolar differentiation and maturation. Lep and Lep-R are strongly expressed by alveolar cells during the saccular stage of fetal lung development. Lep-deficient mice exhibit decreased alveolarization with reduced pulmonary surfactant phospholipid synthesis, similar to human and nitrofen-induced PH. Prenatal administration of all-trans retinoic acid (ATRA) has been shown to stimulate alveolarization in nitrofen-induced PH. Recent studies have demonstrated that Lep and Lep-R expression in developing lungs is regulated by ATRA. We hypothesized that prenatal treatment with ATRA increases pulmonary Lep and Lep-R expression in the nitrofen model of CDH-associated PH. METHODS: Time-mated rats received either 100 mg nitrofen or vehicle via oral-gastric lavage on embryonic day 9.5 (E9.5). Control and nitrofen-exposed dams were randomly assigned to either intraperitoneal ATRA (5 mg/kg/d) or placebo administration on E18.5, E19.5 and E20.5. Fetal lungs were harvested on E21.5, and divided into Control+Placebo, Control+ATRA, Nitrofen+Placebo and Nitrofen+ATRA. Alveolarization was assessed using stereo- and morphometric analysis techniques. Surfactant phospholipid synthesis was analyzed by labeling for surfactant protein B (SP-B). Pulmonary gene expression levels of Lep and Lep-R were determined using quantitative real-time polymerase chain reaction. Immunohistochemical staining for Lep and Lep-R was performed to evaluate alveolar protein expression and localization. RESULTS: In vivo administration of ATRA resulted in significantly increased lung-to-body weight ratio with enhanced radial alveolar count and decreased mean linear intercept compared to placebo treatment. Immunofluorescence analysis demonstrated markedly increased pulmonary SP-B expression in Nitrofen+ATRA compared to Nitrofen+Placebo. Relative mRNA expression of Lep and Lep-R was significantly increased in Nitrofen+ATRA compared to Nitrofen+Placebo. Lep and Lep-R immunoreactivity was markedly increased in interstitial and alveolar epithelial cells of Nitrofen+ATRA compared to Nitrofen+Placebo. CONCLUSION: Increased Lep and Lep-R expression after prenatal administration of ATRA in nitrofen-induced PH suggests that ATRA may have therapeutic potential in attenuating CDH-associated PH by stimulating alveolarization and de novo surfactant production.

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.

Laparoscopic versus Open Inguinal Hernia Repair Is Feasible in Infants with Caudal Anesthesia and Spontaneous Respiration.

INTRODUCTION: Minimally invasive surgery (i.e., laparoscopy) and minimally invasive anesthesia (i.e., caudal anesthesia with spontaneous respiration) have separately shown benefits for inguinal hernia repair in infants, yet to what degree these techniques can be combined remains unknown. This study investigated whether laparoscopy impacts the feasibility of performing caudal anesthesia with spontaneous respiration in infants. METHODS: Prospectively collected data of all infants less than 12 months old and over 3 kg weight who underwent laparoscopic indirect hernia repair (LAP) at our department from 2019 to 2021 were compared with a historical control-matched group of infants who underwent open repair (OPEN) from 2017 to 2021. We assessed the patients' characteristics, anesthesia, and surgical data as well as intra- and postoperative complications. RESULTS: A total of 87 infants were included (LAP n = 29, OPEN n = 58). Caudal anesthesia with spontaneous respiration was feasible in 62.1% of cases (LAP n = 55.2%, OPEN n = 65.5%; nonsignificant). Neither group registered anesthetic intra- or postoperative complications. Sedatives were utilized in 97% of LAP patients versus 56.9% of OPEN patients (p < 0.00001). The airway was secured with a laryngeal mask in 89.7% of patients during LAP versus 41.4% during OPEN (p < 0.00001). No significant differences were found regarding the use frequency of opioids (48.3% LAP vs. 34.5% OPEN; nonsignificant) or neuromuscular blockers (6.9% LAP vs. 5.2% OPEN; nonsignificant). CONCLUSION: This is the first comparative study on caudal anesthesia and spontaneous respiration in infants undergoing laparoscopic versus open inguinal hernia surgery. Laparoscopy increased the need for ventilatory support and sedatives but did not significantly impair the feasibility of caudal anesthesia and spontaneous respiration.

Imbalance of NFATc2 and KV1.5 Expression in Rat Pulmonary Vasculature of Nitrofen-Induced Congenital Diaphragmatic Hernia.

Aim of the Study Nuclear factor of activated T-cell (NFATc2), a Ca2+/calcineurin-dependent transcription factor, is reported to be activated in human and animal pulmonary hypertension (PH). KV1.5, a voltage-gated K+ (KV) channel, is expressed in pulmonary artery smooth muscle cells (PASMC) and downregulated in PASMC in patients and animals with PH. Furthermore, activation of NFATc2 downregulates expression of KV1.5 channels, leading to excessive PASMC proliferation. The aim of this study was to investigate the pulmonary vascular expression of NFATc2 and KV1.5 in rats with nitrofen-induced congenital diaphragmatic hernia (CDH). Materials and Methods After ethical approval, time-pregnant Sprague-Dawley rats received nitrofen or vehicle on gestational day 9 (D9). When sacrificed on D21, the fetuses (n = 22) were divided into CDH and control groups. Using quantitative real-time polymerase chain reaction and western blotting, we determined the gene and protein expression of NFATc2 and KV1.5. Confocal microscopy was used to detect both proteins in the pulmonary vasculature. Results Relative mRNA levels of NFATc2 were significantly upregulated and KV1.5 levels were significantly downregulated in CDH lungs compared with controls (p < 0.05). Western blotting confirmed the imbalanced pulmonary protein expression of both proteins. An increased pulmonary vascular expression of NFATc2 and a diminished expression of KV1.5 in CDH lungs compared with controls were seen in confocal microscopy. Conclusions This study demonstrates for the first time an altered gene and protein expression of NFATc2 and KV1.5 in the pulmonary vasculature of nitrofen-induced CDH. Upregulation of NFATc2 with concomitant downregulation of KV1.5 channels may contribute to abnormal vascular remodeling resulting in PH in this model.

The Role of Activin Receptor-Like Kinase 1 Signaling in the Pulmonary Vasculature of Experimental Diaphragmatic Hernia.

AIM: The high morbidity and mortality in newborn infants diagnosed with congenital diaphragmatic hernia (CDH) is widely recognized to be due to pulmonary hypoplasia and persistent pulmonary hypertension (PH). The underlying structural and molecular pathomechanisms causing PH are not fully understood. Recently, activin receptor-like kinase 1 (ALK-1), an endothelial cell (EC) receptor, has been implicated in the pathogenesis of PH. ALK-1 transmits signals via a Smad pathway stimulating EC proliferation and migration leading to structural lung remodeling consecutively resulting in PH. Increased pulmonary expression of ALK-1 has been reported in patients with severe PH as well as in experimental models of PH. We designed this study to investigate the hypothesis that pulmonary ALK-1 expression is increased in nitrofen-induced CDH. METHODS: Pregnant rats were exposed to nitrofen or vehicle on D9. Fetuses were sacrificed on D21 and divided into nitrofen (n = 16) and control group (n = 16). Quantitative real-time polymerase chain reaction, Western blotting, and confocal-immunofluorescence microscopy were performed to determine pulmonary gene and protein expression as well as vascular localization of expressed ALK-1. RESULTS: Pulmonary gene expression levels of ALK-1 were significantly upregulated in nitrofen-treated lung tissue compared with controls. Western blotting showed increased pulmonary protein expression for ALK-1 in the CDH group when compared with control lung tissue. Confocal microscopy demonstrated markedly increased medial and adventitial thickness of pulmonary arteries in the CDH group and revealed increased ALK-1 protein expression of the pulmonary vasculature of CDH pups compared with controls. CONCLUSION: Upregulated gene and increased protein expression of ALK-1 in the pulmonary vasculature of nitrofen-induced CDH suggest that increased expression of ALK-1 may play a crucial role in the molecular pathogenesis of vascular remodeling induced PH in experimental CDH.

Kif7 expression is decreased in the diaphragmatic and pulmonary mesenchyme of nitrofen-induced congenital diaphragmatic hernia.

PURPOSE: Developmental mutations that inhibit diaphragmatic and pulmonary mesenchyme formation have been shown to cause congenital diaphragmatic hernia (CDH) and pulmonary hypoplasia (PH). Kinesin family member 7 (Kif7) plays a crucial role in diaphragmatic and pulmonary morphogenesis by controlling proliferation of mesenchymal cells. Loss of Kif7 has been reported to result in diaphragmatic defects and PH. We hypothesized that diaphragmatic and pulmonary Kif7 expression is decreased in the nitrofen-induced CDH model. METHODS: Timed-pregnant rats were exposed to either nitrofen or vehicle on gestational day 9 (D9). Fetal diaphragms and lungs were microdissected on D13, D15, and D18, and divided into control and nitrofen-exposed specimens. Gene expression levels of Kif7 were analyzed by qPCR. Immunohistochemical staining was performed to evaluate Kif7 protein expression. RESULTS: Relative mRNA expression of Kif7 was significantly reduced in pleuroperitoneal folds (D13), developing diaphragms and lungs (D15), and fully muscularized diaphragms and differentiated lungs (D18) of nitrofen-exposed fetuses compared to controls. Immunoreactivity/immunofluorescence of Kif7 was markedly decreased in diaphragmatic and pulmonary mesenchyme of nitrofen-exposed fetuses on D13, D15, and D18 compared to controls. CONCLUSION: Decreased Kif7 expression during diaphragmatic development may interfere with mesenchymal cell proliferation, leading to defective pleuroperitoneal folds, and resulting in diaphragmatic defects and associated PH in the nitrofen-induced CDH model.

Expression of Eya1 and Six1 is decreased in distal airways of rats with experimental pulmonary hypoplasia.

BACKGROUND/PURPOSE: Pulmonary hypoplasia (PH) associated with congenital diaphragmatic hernia (CDH) represents one of the major challenges in neonatal intensive care. Eyes absent 1 (Eya1) and sine oculis homebox 1 (Six1) have been identified as essential components of the gene network that regulates foetal lung development. Eya1 and Six1 are expressed in distal epithelial tips of branching airways as well as in surrounding mesenchymal cells, highlighting their important role during branching morphogenesis. Lungs of Eya1(-/-) and Six1(-/-) knockouts display PH with reduced epithelial branching, appearing to be arrested in the pseudoglandular stage. We hypothesized that Eya1 and Six1 expression is decreased in branching airways of nitrofen-induced PH. METHODS: Time-mated rats received either nitrofen or vehicle on E9.5. Foetal lungs were dissected on E15.5 and divided into control and nitrofen groups, whereas lungs harvested on E18.5 were divided into controls, PH without CDH [PH(-)], and PH with CDH [PH(+)]. Pulmonary gene expression levels of Eya1 and Six1 were analyzed by quantitative real-time PCR. Immunofluorescence staining was performed to investigate Eya1 and Six1 protein expression and localization by confocal laser scanning microscopy (CLSM). RESULTS: Relative mRNA expression of Eya1 and Six1 was significantly decreased in PH(-) and PH(+) on E18.5 compared to controls. CLSM confirmed markedly diminished immunofluorescence of Eya1 and Six1 in distal airway epithelium as well as in surrounding mesenchymal cells of nitrofen-induced PH on E18.5 compared to controls. CONCLUSIONS: Downregulation of Eya1 and Six1 gene expression in nitrofen-induced PH suggests that decreased Eya1 and Six1 expression during the late pseudoglandular stage may interfere with epithelial branching and distal airway maturation, thus resulting in PH.

Implementation of fast-track pediatric surgery in a German nonacademic institution without previous fast-track experience.

Fast-track concepts in pediatric surgery were established in a university hospital in consecutive studies within several years. They significantly reduced the length of hospitalization compared with German institutions without fast-track protocols. The aim of this study was to assess the implementation process of fast-track in a German nonacademic department of pediatric surgery without previous fast-track experience. All patients undergoing four types of operations (appendectomy, hypospadias repair, pyloromyotomy, and fundoplication) from February 2011 to January 2012 were included in this prospective study. Fast-track included detailed clinical pathways and specific pain treatment protocols using validated pain scales according to age. Mobilization and oral nutrition were started 2 hours postoperatively and documented with established scores. The length of hospital stay was compared with data from other hospitals with conventional treatment using information from the German reimbursement system (German diagnosis-related groups [G-DRG]) and with the hospital stay of patients from the corresponding university hospital undergoing fast-track treatment for the same procedures during the same study period. Two weeks after discharge, a questionnaire was completed by the patients/parents. A total of 143 patients with a mean age of 7.9 ± 5.0 years underwent fast-track treatment. The mean pain intensity during the immediate postoperative period was 1.7 ± 2.1 in patients < 4 years and 2.3 ± 2.1 in patients ≥ 4 years on a 10-point scale. Full mobilization was reached after a mean duration of 2.3 ± 2.0 days while full oral nutrition was completed after a mean duration of 1.8 ± 1.4 days. There were no complications associated with fast-track. The mean hospital stay was 5.8 ± 3.4 days which was not significantly different compared with G-DRG data from other hospitals without fast-track. This was in contrast to the mean hospital stay of patients from the corresponding university hospital (5.6 ± 3.0 days vs. G-DRG 6.9 ± 3.2 days, p < 0.05). After 2 weeks, patients/parents were highly satisfied with fast-track (mean score of 8.6 ± 1.4 on a 1-10-point scale) and 95.2% claimed that they would choose it again. Fast-track concepts can be applied in a nonacademic department of pediatric surgery without previous fast-track experience and with excellent patient/parent satisfaction. However, the G-DRG system interferes with concepts of early discharge of patients. Modifications of the reimbursement modalities within the German health care system seem to be mandatory.