Therapeutic potential of all-trans retinoic acid to attenuate pulmonary hypoplasia in an experimental rat model of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a prenatal defect in the integrity of the developing diaphragm, which results in pulmonary hypoplasia (PH) with alveolar immaturity. PH leads to life-threatening respiratory insufficiency at birth, thus remaining a major cause of neonatal mortality in CDH. Lipid-containing interstitial fibroblasts (LIFs) are crucial for fetal lung growth by stimulating alveolarization and surfactant phospholipid production in alveolar epithelial cells type II (AECII), which in turn increases alveolar maturation. Thymocyte antigen 1 (Thy-1) is a strongly expressed cell surface protein in LIFs, which plays a key role in alveolar lipid homeostasis by upregulating adipocyte differentiation-related protein (Adrp). Adrp is necessary for the intracellular uptake of neutral lipids into LIFs and their transport to AECII. Furthermore, LIFs express leptin (Lep), which binds to its receptor (Lep-R) on AECII, thus stimulating de novo synthesis and secretion of surfactant proteins. As Thy-1-/- knockout animals show a phenotype similar to PH in human CDH with impaired alveolar development and reduced proliferation of LIFs, the first objective of this study was to identify disruptions in Thy-1 signaling in hypoplastic rat lungs with toxicological induced CDH, which may have an adverse effect on the expression and lipid content of pulmonary LIFs. In addition, as it has been demonstrated that retinoids positively affect the proliferation of LIFs and expression of Lep and Lep-R in developing rat lungs, the second objective was to investigate if prenatal administration of all-trans retinoic acid (ATRA) may have the potential to attenuate PH in this rodent CDH model by improving fetal alveolarization and surfactant production. This study revealed that disruption of the Thy-1/Adrp signaling cascade in hypoplastic rat lungs leads to a reduction of pulmonary LIFs with significantly fewer cytoplasmatic lipid inclusions and impaired alveolar mesenchymal cell differentiation, which may contribute to decreased alveolar development and PH in the nitrofen-induced CDH model. Prenatal treatment with ATRA may therefore have a therapeutic potential in attenuating CDH-associated PH by increasing the overall number of LIFs and lipid droplets through an upregulation of Adrp transcripts and corresponding protein expression, and consequently enhances Lep-mediated surfactant phospholipid synthesis, which in turn stimulates fetal alveolarization, distal airway maturation and de novo surfactant production.Synnynnäisessä palleatyrässä kehittyvään palleaan muodostuu sikiöaikana defekti, joka johtaa keuhkojen hypolasiaan ja alveolien epäkypsyyteen. Syntymän jälkeen keuhkojen hypoplasia johtaa henkeä uhkaavaan hengitysvajaukseen, joka on yleisin vastasyntyneen kuolemansyy synnynnäistä palleatyrää sairastavilla. Lipid-containing interstitial fibroblastit (LIFs) stimulivat keuhkojen alveolarisaatiota ja surfaktantin tuotantoa alveolien epiteelisoluissa (tyyppi II, AECII) ja ovat siten tärkeitä sikiön keuhkojen kehitykselle. LIF solujen pintaproteiini Thymocyte antigen 1 (Thy-1) osallistuu alveolien lipiditasapainon säätelyyn lisäämällä Adr-proteiinin (adipocyte differentiation-related protein) esiintymistä. Adr-proteiini on välttämätön, jotta neutraalit lipidit pääsevät LIF soluihin ja AECII soluihin. Lisäksi LIF solut ekspressoivat leptiiniä (Lep), joka sitoutuu AECII solujen Leptiini reseptoriin (Lep-R), joka de novo stimuloi surfaktanttiproteiinien synteesiä ja eritystä. Synnynnäistä palleatyrää voidaan tutkia Thy-1-/- knockout eläinmallin avulla. Thy-1-/- knockout eläimillä todetaan keuhkojen hypoplasia, poikkeava alveolien kehitys ja vähentynyt LIF solujen proliferaatio, kuten synnynnäistä palleatyrää sairastavilla ihmisillä. Tämän tutkimuksen ensimmäisenä tavoitteena oli tunnistaa Thy-1 signaloinnin poikkeavuuksia rotilla, joille oli aiheutettu synnynnäinen palleatyrä ja keuhkojen hypoplasia toksikologisesti. Aikaisemmin on todettu, että retinoidit vaikuttavat positiivisesti LIF solujen proliferaatioon sekä Lep- ja Lep-R ekspressioon kehittyvissä rotan keuhkoissa. Tutkimuksen toisena tavoitteena oli tutkia prenataalisesti annetun all-trans retinoidihapon (ATRA) potentiaalia parantaa sikiöaikaista alveolarisaatiota ja surfraktantin tuotantoa ja edelleen lieventää keuhkojen hypoplasiaa synnynnäisen palleatyrän eläinmallissa. Tässä tutkimuksessa havaittiin, että rotan hypoplastisissa keuhkoissa häiriöt Thy-1/Adr-signaalikaskadissa johtavat keuhkojen LIF solujen ja sytoplasman lipidipisaroiden määrän vähenemiseen sekä heikentyneeseen alveolien mesenlyymisolujen erilaistumiseen, joka saattaa vaikuttaa alveolien kehittymiseen sekä keuhkojen hypoplasiaan. Prenataalisesti annetulla ATRA-hoidolla saattaa olla terapeuttista potentiaalia kongenitaalisen palleatyrään liittyvän keuhkojen hypoplasian hoidossa, sillä se kasvattaa LIF solujen ja sytoplasman lipidin määrää säätelemällä Adrp- geeni ja -proteiini ekspressiota sekä Lep-välitteistä surfaktantin synteesiä, joka edelleen stimuloi sikiöaikaista alveolarisaatiota, distaalisten ilmateiden kypsymistä ja de novo surfaktantin tuotantoa

Effects of the peroxisome proliferator-activated receptor y agonist rosiglitazone on foetal lung development in an experimental rat model of congenital diaphragmatic hernia.

Congenital diaphragmatic hernia (CDH) is a prenatal defect in the integrity of the developing diaphragm, which results in severe pulmonary hypoplasia (PH) with alveolar immaturity. Peroxisome proliferator-activated receptor y (PPARy) plays a key role in foetal alveolarization by coordinating alveolar cell proliferation and differentiation, which results in enhanced expression of alveolar lipid-containing interstitial fibroblasts (LIFs). Furthermore, PPARy increases the lipid content of alveolar LIFs by upregulation of adipocyte differentiation-related protein (ADRP), a lipogenic marker for alveolar mesenchymal differentiation and physiological determinant for the synthesis of surfactant phospholipids. Since PPARy transcripts and alveolar LIFs are significantly decreased in hypoplastic rat lungs, the overall aim of this work was to investigate the hypothesis that the synthetic PPARy agonist rosiglitazone (RGZ) has the potential to improve foetal alveolar development in the nitrofen rat model of CDH-associated PH. The first objective of this work was to examine the in vitro effects of RGZ treatment in an explant culture of foetal rat lungs. Morphometric analysis revealed that daily administration of RGZ enhances alveolarization in nitrofen-exposed hypoplastic lungs compared to Placebo-treated lung explants, which was further supported by a significantly increased radial alveolar count and decreased mean linear intercept. The second objective was to evaluate the in vivo effects of prenatally administered RGZ on alveolar development and maturation in foetal rats with CDH. lmmunohistochemical/-fluorescence analysis demonstrated that maternal administration of RGZ shortly before birth stimulates epithelial and mesenchmal differentiation in nitrofen-induced PH compared to Placebo-treated foetuses, as evidenced by increased lamellar body count and ADRP expression. There was also a substantial accumulation of cytoplasmatic lipid droplets in alveolar interstitial cells, which was accompanied by a markedly increase of LIFs in the mesenchymal compartments of distal alveolar walls. Taken together, these results suggest that RGZ has a therapeutic potential in attenuating foetal PH in rats with nitrofen-induced CDH through accelerating epithelial-mesenchymal interactions, which may result in enhanced expression of LIFs and thus alveolar maturation

Prenatal treatment with rosiglitazone attenuates vascular remodeling and pulmonary monocyte influx in experimental congenital diaphragmatic hernia

Publication history: Accepted - 23 October 2018; Published online - 12 November 2018.Introduction Extensive vascular remodeling causing pulmonary hypertension (PH) represents a major cause of mortality in patients with congenital diaphragmatic hernia (CDH). The chemokine monocyte chemoattractant protein-1 (MCP-1) is a biomarker for the severity of PH and its activation is accompanied by pulmonary influx of monocytes and extensive vascular remodeling. MCP-1 activation can be reversed by application of rosiglitazone (thiazolidinedione). We performed this study to evaluate the role of MCP-1 for the pathogenesis of PH in experimental CDH. We hypothesized that vascular remodeling and MCP-1 activation is accompanied by pulmonary influx of fetal monocytes and can be attenuated by prenatal treatment with rosiglitazone. Methods In a first set of experiments pregnant rats were treated with either nitrofen or vehicle on gestational day 9 (D9). Fetal lungs were harvested on D21 and divided into CDH and control. Quantitative real-time polymerase chain reaction, Western blot (WB), and immunohistochemistry (IHC) were used to evaluate MCP-1 expression, activation, and localization. Quantification and localization of pulmonary monocytes/macrophages were carried out by IHC. In a second set of experiments nitrofen-exposed dams were randomly assigned to prenatal treatment with rosiglitazone or placebo on D18+D19. Fetal lungs were harvested on D21, divided into control, CDH+rosiglitazone, and CDH+placebo and evaluated by WB as well as IHC. Results Increased thickness of pulmonary arteries of CDH fetuses was accompanied by increased systemic and perivascular MCP-1 protein expression and significantly higher amounts of pulmonary monocytes/macrophages compared to controls (p<0.01). These effects were reversed by prenatal treatment with rosiglitazone (p<0.01 vs. CDH+P; control). Conclusion Prenatal treatment with rosiglitazone has the potential to attenuate activation of pulmonary MCP-1, pulmonary monocyte influx, and vascular remodeling in experimental CDH. These results provide a basis for future research on prenatal immunomodulation as a novel treatment strategy to decrease secondary effects of PH in CDH.This work was supported by Children’s Medical & Research Foundation, Dublin, Ireland, https://cmrf.org/, Senior Research Fellowship JG, awarded to JG; German Research Foundation and Leipzig University within the program of Open Access Publishing, awarded to JG, https://www.ub.uni-leipzig.de/open-science/publikationsfonds/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

NADPH oxidase-derived H2O2 subverts pathogen signaling by oxidative phosphotyrosine conversion to PB-DOPA

Strengthening the host immune system to fully exploit its potential as antimicrobial defense is vital in countering antibiotic resistance. Chemical compounds released during bidirectional host–pathogen cross-talk, which follows a sensing-response paradigm, can serve as protective mediators. A potent, diffusible messenger is hydrogen peroxide (H(2)O(2)), but its consequences on extracellular pathogens are unknown. Here we show that H(2)O(2), released by the host on pathogen contact, subverts the tyrosine signaling network of a number of bacteria accustomed to low-oxygen environments. This defense mechanism uses heme-containing bacterial enzymes with peroxidase-like activity to facilitate phosphotyrosine (p-Tyr) oxidation. An intrabacterial reaction converts p-Tyr to protein-bound dopa (PB-DOPA) via a tyrosinyl radical intermediate, thereby altering antioxidant defense and inactivating enzymes involved in polysaccharide biosynthesis and metabolism. Disruption of bacterial signaling by DOPA modification reveals an infection containment strategy that weakens bacterial fitness and could be a blueprint for antivirulence approaches

Differences in cardiorespiratory fitness in prediabetic individuals with normal versus impaired glucose tolerance

Bewegungsmangel, Adipositas und gestörte Glukosetoleranz (IGT) sind bekanntlich mit einem erhöhten Risiko für die Entwicklung eines Diabetes mellitus Typ 2 (DM2) assoziiert. Allerdings ist derzeit unklar, ob Personen mit normaler Glukosetoleranz (NGT), die jedoch Risikofaktoren für einen DM2 aufweisen (z.B. Fettleibigkeit, positive Familienanamnese für DM2, Gestationsdiabetes) von einer Lebensstil-Intervention (LSI) mit Steigerung der körperlichen Aktivität profitieren können. HYPOTHESE: Um zu zeigen, dass sich im Rahmen einer LSI die kardiopulmonale Leistungsfähigkeit von Personen mit NGT und IGT sowohl im maximalen als auch im sub-maximalen Ausdauerbereich unterscheidet, werden durch spiroergometrische Unter-suchungen und Laktatdiagnostik maximale Sauerstoffaufnahme (VO2max), Leistung an der Individuell Anaeroben Schwelle (IAS), sowie Anaerobic Threshold (AT) und Lactate Threshold (LT) bestimmt. Dabei sollen mögliche Einflüsse von körperlicher Alltagsaktivität (HPA), Body Mass Index (BMI), prozentualem Körperfettanteil (%KF) und Alter dargestellt werden. METHODEN: 257 Probanden (181 mit NGT und 76 mit IGT) mit diversen Risikofaktoren für einen DM2, die am TUebinger Lebensstil Interventions-Programm (TULIP) teilnahmen, wurden in der vorliegenden Studie eingeschlossen. Alle Teilnehmer erhielten einen oralen Glukosetoleranztest (OGTT) sowie einen standardisierten Fragebogen um die HPA zu bestimmen. Auf einem Laufband wurde während stufenförmiger Belastung mittels Spiro-ergometrie und Laktatdiagnostik VO2max und Leistung an der IAS ermittelt. ERGEBNISSE: Studienteilnehmer mit NGT waren weniger adipös (38,1 % vs. 52,6 %; p < 0,001), obwohl sich BMI (p = 0,43) und fettfreie Masse (FFM) (p = 0,37) nicht zwischen den beiden Testgruppen unterschieden. Gleiches galt für die HPA (p = 0,96). Probanden mit NGT hatten die höhere absolute VO2max (2513,25 ± 626,83 vs. 2298,88 ± 561,26 ml · min-1; p < 0,01) und erzielten höhere Leistungen an der IAS (71 ± 44 vs. 52 ± 38 Watt; p < 0,002). Größere BMI-Werte waren mit niedriger VO2max (ml · kg FFM-1 · min-1) vergesell-schaftet (r = -0,27 vs. r = -0,45; p < 0,001). BMI (r = -0,33 vs. r = -0,40; p < 0,001) und %KF (r = -0,62 vs. r = -0,53; p < 0,001) korrelierten jeweils negativ mit der Leistung an der IAS. Überraschenderweise korrelierten VO2max (ml · kg FFM-1 · min-1) (r = 0,18; p = 0,01) und Leistung an der IAS (r = 0,20; p < 0,01) nur bei Personen mit NGT positiv mit der HPA, wohingegen HPA und BMI negativ miteinander korrelierten (r = -0,19; p < 0,01). SCHLUSSFOLGERUNG: Ein positiver Einfluss von HPA konnte nur bei Prädiabetikern mit NGT beobachtet werden. Folglich haben diese eine bessere Prädisposition für eine erfolgreiche LSI, wohingegen die Ausdauerleistungsfähigkeit von Personen mit IGT allein von anthropometrischen und metabolischen Größen beeinflusst wird. Weitere Studien sind notwendig, um zu beweisen, dass diese Subpopulation von einem mehr individualisierten Interventionsprogramm profitieren kann, welches primär auf eine Verminderung des BMI und des %KF abzielt. Weiterhin könnten genetische Analysen dazu beitragen die großen Leistungsunterschiede zu erklären.Sedentary lifestyle, obesity and impaired glucose tolerance (IGT) are associated with the risk of type 2 diabetes (T2D). However, it is currently unknown whether a lifestyle intervention (LSI) with increased physical activity is effective in subjects with normal glucose tolerance (NGT) who are at risk for T2D (e.g. because of being overweight or having a family history of T2D). PURPOSE: To reveal whether subjects with NGT will response differently to a standardized LSI we investigated their baseline cardiopulmonal fitness in comparison to subjects with IGT. Therefore, the impact of physical activity, BMI and total body fat (TBF) shall be exposed. METHODS: 257 subjects (181 with NGT and 76 with IGT) with increased risk for T2D, who participated in the TUebingen Lifestyle Intervention Program (TULIP) were included in the present study. All individuals received the oral glucose tolerance test (OGTT) and completed a standardized self-administered questionnaire to determine Habitual Physical Activity (HPA) and underwent an incremental exercise test for measurement of the maximal aerobic capacity (VO2max) and work rate (WR) at the individual anaerobic threshold (IAT). RESULTS: Obesity was less frequently in subjects with NGT (38.1 % vs. 52.6 %; p < 0.001), although BMI (p = 0.52) and TBF (p = 0.79) were not different between the groups. HPA was similar as well (p = 0.96). VO2max (2513.29 ± 626.83 vs. 2298.88 ± 561.26 ml/min; p < 0.01) and WR at the IAT (71 ± 44 vs. 52 ± 38 Watts; p < 0.005) were higher in individuals with NGT. High levels of BMI were associated with lower values of VO2max (r = -0.27 vs. r = -0.45; p < 0.001). BMI (r = -0.33 vs. r = -0.40; p < 0.001) and TBF (r = -0.62 vs. r = -0.53; p < 0.001) were both negatively correlated with WR at the IAT. Surprisingly, HPA was positively correlated with VO2max (r = 0.18; p = 0.01) and WR at the IAT (r = 0.20; p < 0.01) only among subjects with NGT, whereas HPA and BMI were inverse correlated (r = -0.19; p < 0.01). CONCLUSION: The protective effect of HPA was observed mainly in prediabetic subjects with NGT. Thus, they seem to have the better predisposition for a successful LSI. Furhter studies will need to show whether individuals with IGT can profit from a more individualized LSI with combination of physical activity and dietary counseling to reduce BMI and TBF. Otherwise genetics may help explain the large variation in response to physical exercise

Congenital diaphragmatic hernia : a scientometric analysis of the global research activity and collaborative networks

Despite a growing interest to clinicians and scientists, there is no comprehensive study that examines the global research activity on congenital diaphragmatic hernia (CDH). A search strategy for the Web of Science (TM) database was designed to identify scientific CDH publications. Research output of countries, institutions, individual authors, and collaborative networks was analyzed. Semi-qualitative research measures including citation rate and h-index were assessed. Choropleth mapping and network diagrams were employed to visualize results. A total of 3669 publications were found, originating from 76 countries. The largest number was published by the USA (n = 1250), the UK (n = 279), and Canada (n = 215). The USA combined the highest number of cooperation articles (n = 152), followed by Belgium (n = 115) and the Netherlands (n = 93). The most productive collaborative networks were established between UK/Belgium (n = 53), Belgium/Spain (n = 47), and UK/Spain (n = 34). Canadian publications received the highest average citation rate (22.8), whereas the USA had the highest country-specific h-index (72). Eighty-five (2.3%) articles were published by international multicenter consortiums and national research networks. The most productive institutions and authors were based in North America and Europe. Over the past decades, CDH research has increasingly become multidisciplinary and numerous innovative therapeutic strategies were introduced. CDH-related research has constantly been progressing, involving today many disciplines with main research endeavors concentrating in a few high-income countries. Recent advances in prenatal interventions and regenerative medicine therapy hold the promise of improving CDH outcome in the 21st century. International collaborations and translational research should be strengthened to allow further evolution in this field.Peer reviewe

Gastroesophageal reflux disease and need for antireflux surgery in children with cystic fibrosis: a systematic review on incidence, surgical complications, and postoperative outcomes

Introduction: Gastroesophageal reflux disease (GERD) is associated with accelerated decline in lung health in children with cystic fibrosis (CF). Thus, antireflux surgery (ARS) is offered to a selected CF cohort with refractory GERD, but outcomes remain poorly investigated. This study aimed to determine the incidence of GERD in children with CF and to evaluate complications and outcomes of ARS. Materials and Methods: A systematic literature-based search was conducted using various online databases according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The number of GERD cases in pediatric CF cohorts who underwent diagnostic investigation(s) was recorded. Data on postoperative complications and outcomes (including symptoms, lung function, and nutritional status) following ARS were analyzed. Results: Ten articles (n = 289 patients) met the defined inclusion criteria (51% male; age range, 0.5 month–36 years). The overall incidence of GERD was 46% (range, 19–81%), derived from seven studies (n = 212 patients). Four publications (n = 82 patients) reported on ARS due to uncontrolled GERD. All ARSs were Nissen fundoplication (majority with gastrostomy placement). Major postoperative complications occurred in 15 (18%) patients, two required redo-ARS. Median follow-up time was 2 years (range, 3 months–6 years); 59% showed symptom improvement, and pulmonary exacerbations and decline in lung function were reduced. Nutritional status mainly improved in milder CF cases. There were no deaths related to ARS. Conclusion: Approximately half of pediatric CF patients have GERD. Published data for children with CF are limited and heterogeneous in terms of GERD diagnosis and outcomes following ARS. However, ARS has shown to slow the deterioration of lung function in CF

Transgenic animal models of congenital diaphragmatic hernia: a comprehensive overview of candidate genes and signaling pathways

Congenital diaphragmatic hernia (CDH) is a relatively common and life-threatening birth defect, characterized by incomplete formation of the diaphragm. Because CDH herniation occurs at the same time as preacinar airway branching, normal lung development becomes severely disrupted, resulting almost invariably in pulmonary hypoplasia. Despite various research efforts over the past decades, the pathogenesis of CDH and associated lung hypoplasia remains poorly understood. With the advent of molecular techniques, transgenic animal models of CDH have generated a large number of candidate genes, thus providing a novel basis for future research and treatment. This review article offers a comprehensive overview of genes and signaling pathways implicated in CDH etiology, whilst also discussing strengths and limitations of transgenic animal models in relation to the human condition

C-reactive protein/albumin ratio is a prognostic indicator for predicting surgical intervention and mortality in neonates with necrotizing enterocolitis

Purpose!#!The role of hypoalbuminemia and raised C-reactive protein (CRP) levels in predicting critical prognosis has been described extensively in adult literature. However, there are limited studies in pediatrics, particularly neonates. The CRP/albumin (CRP/ALB) ratio is often associated with higher mortality, organ failure and prolonged hospital stay. We hypothesized that the serum CRP/ALB ratio has a prognostic value in predicting surgery and mortality in neonates with necrotizing enterocolitis (NEC).!##!Methods!#!Retrospective review of all neonates with clinical and radiological evidence of non-perforated NEC that were treated in a tertiary-level referral hospital between 2009 and 2018. General patient demographics, laboratory parameters and outcomes were recorded. Receiver operating characteristics analysis was performed to evaluated optimal cut-offs and area under the curve (AUC) with 95% confidence intervals (CI).!##!Results!#!A total of 191 neonates were identified. Of these, 103 (53.9%) were born at ≤ 28 weeks of gestation and 101 (52.9%) had a birth weight of ≤ 1000 g. Eighty-four (44.0%) patients underwent surgical intervention for NEC. The overall survival rate was 161/191 (84.3%). A CRP/ALB ratio of ≥ 3 on day 2 of NEC diagnosis was associated with a statistically significant higher likelihood for surgery [AUC 0.71 (95% CI 0.63-0.79); p &amp;lt; 0.0001] and mortality [AUC 0.66 (95% CI 0.54-0.77); p = 0.0150], respectively.!##!Conclusions!#!A CRP/ALB ratio of ≥ 3 on day 2 is indicative of a critical pathway in neonates with radiologically confirmed, non-perforated NEC. This could be used as an additional criterion to guide parental counselling in NEC for surgical intervention and mortality