Early Pulmonary Interstitial Emphysema in Preterm Neonates-Respiratory Management and Case Report in Nonventilated Very Low Birth Weight Twins

Early pulmonary interstitial emphysema in extreme preterm neonates is closely linked with respiratory distress syndrome and exposure to mechanical ventilation. In severe cases, maintaining adequate gas exchange aiming to avoid further lung damage and other neonatal morbidities associated with systemic/pulmonary hypoperfusion, prolonged hypoxia, and respiratory acidosis can be challenging and requires in-depth knowledge into the pathophysiology of the disease. Herein, we report on very low birth weight twins who developed early pulmonary interstitial emphysema during noninvasive respiratory support. We further review the current evidence from the literature, specifically addressing on possible preventive measures and the respiratory management options of this acute pulmonary disease in high-risk neonates.

Fgf10 deficiency is causative for lethality in a mouse model of bronchopulmonary dysplasia

Inflammation-induced FGF10 protein deficiency is associated with bronchopulmonary dysplasia (BPD), a chronic lung disease of prematurely born infants characterized by arrested alveolar development. So far, experimental evidence for a direct role of FGF10 in lung disease is lacking. Using the hyperoxia-induced neonatal lung injury as a mouse model of BPD, the impact of Fgf10 deficiency in Fgf10^+/- versus Fgf10^+/+ pups was investigated. In normoxia, no lethality of Fgf10^+/+ or Fgf10^+/- pups was observed. By contrast, all Fgf10^+/- pups died within 8 days of hyperoxic injury, with lethality starting at day 5, whereas Fgf10^+/+ pups were all alive. Lungs of pups from the two genotypes were collected on postnatal day 3 following normoxia or hyperoxia exposure for further analysis. In hyperoxia, Fgf10^+/- lungs exhibited increased hypoalveolarization. Analysis by FACS of the Fgf10^+/- versus control lungs in normoxia revealed a decreased ratio of alveolar epithelial type II (AECII) cells over total Epcam-positive cells. In addition, gene array analysis indicated reduced AECII and increased AECI transcriptome signatures in isolated AECII cells from Fgf10^+/- lungs. Such an imbalance in differentiation is also seen in hyperoxia and is associated with reduced mature surfactant protein B and C expression. Attenuation of the activity of Fgfr2b ligands postnatally in the context of hyperoxia also led to increased lethality with decreased surfactant expression. In summary, decreased Fgf10 mRNA levels lead to congenital lung defects, which are compatible with postnatal survival, but which compromise the ability of the lungs to cope with sub-lethal hyperoxic injury. Fgf10 deficiency affects quantitatively and qualitatively the formation of AECII cells. In addition, Fgfr2b ligands are also important for repair after hyperoxia exposure in neonates. Deficient AECII cells could be an additional complication for patients with BPD. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Gene expression profiling at birth characterizing the preterm infant with early onset infection

Abstract

Early onset infection (EOI) in preterm infants <32 weeks gestational age (GA) is associated with a high mortality rate and the development of severe acute and long-term complications. The pathophysiology of EOI is not fully understood and clinical and laboratory signs of early onset infections in this patient cohort are often not conclusive. Thus, the aim of this study was to identify signatures characterizing preterm infants with EOI by using genome-wide gene expression (GWGE) analyses from umbilical arterial blood of preterm infants. This prospective cohort study was conducted in preterm infants <32 weeks GA. GWGE analyses using CodeLink human microarrays were performed from umbilical arterial blood of preterm infants with and without EOI. GWGE analyses revealed differential expression of 292 genes in preterm infants with EOI as compared to infants without EOI. Infants with EOI could be further differentiated into two subclasses and were distinguished by the magnitude of the expression of genes involved in both neutrophil and T cell activation. A hallmark activity for both subclasses of EOI was a common suppression of genes involved in natural killer (NK) cell function, which was independent from NK cell numbers. Significant results were recapitulated in an independent validation cohort. Gene expression profiling may enable early and more precise diagnosis of EOI in preterm infants.

Key message

Gene expression (GE) profiling at birth characterizes preterm infants with EOI.

GE analysis indicates dysregulation of NK cell activity.

NK cell activity at birth may be a useful marker to improve early diagnosis of EOI.

Electronic supplementary material

The online version of this article (doi:10.1007/s00109-016-1466-4) contains supplementary material, which is available to authorized users.

Pathogenesis of bronchopulmonary dysplasia: when inflammation meets organ development

Bronchopulmonary dysplasia is a chronic lung disease of preterm infants. It is caused by the disturbance of physiologic lung development mainly in the saccular stage with lifelong restrictions of pulmonary function and an increased risk of abnormal somatic and psychomotor development. The contributors to this disease’s entity are multifactorial with pre- and postnatal origin. Central to the pathogenesis of bronchopulmonary is the induction of a massive pulmonary inflammatory response due to mechanical ventilation and oxygen toxicity. The extent of the pro-inflammatory reaction and the disturbance of further alveolar growth and vasculogenesis vary largely and can be modified by prenatal infections, antenatal steroids, and surfactant application.

This minireview summarizes the important recent research findings on the pulmonary inflammatory reaction obtained in patient cohorts and in experimental models. Unfortunately, recent changes in clinical practice based on these findings had only limited impact on the incidence of bronchopulmonary dysplasia.

Absence of TNF-α enhances inflammatory response in the newborn lung undergoing mechanical ventilation

Bronchopulmonary dysplasia (BPD), characterized by impaired alveolarization and vascularization in association with lung inflammation and apoptosis, often occurs after mechanical ventilation with oxygen-rich gas (MV-O2). As heightened expression of the proinflammatory cytokine TNF-α has been described in infants with BPD, we hypothesized that absence of TNF-α would reduce pulmonary inflammation, and attenuate structural changes in newborn mice undergoing MV-O2 Neonatal TNF-α null (TNF-α(-/-)) and wild type (TNF-α(+/+)) mice received MV-O2 for 8 h; controls spontaneously breathed 40% O2 Histologic, mRNA, and protein analysis in vivo were complemented by in vitro studies subjecting primary pulmonary myofibroblasts to mechanical stretch. Finally, TNF-α level in tracheal aspirates from preterm infants were determined by ELISA. Although MV-O2 induced larger and fewer alveoli in both, TNF-α(-/-) and TNF-α(+/+) mice, it caused enhanced lung apoptosis (TUNEL, caspase-3/-6/-8), infiltration of macrophages and neutrophils, and proinflammatory mediator expression (IL-1β, CXCL-1, MCP-1) in TNF-α(-/-) mice. These differences were associated with increased pulmonary transforming growth factor-β (TGF-β) signaling, decreased TGF-β inhibitor SMAD-7 expression, and reduced pulmonary NF-κB activity in ventilated TNF-α(-/-) mice. Preterm infants who went on to develop BPD showed significantly lower TNF-α levels at birth. Our results suggest a critical balance between TNF-α and TGF-β signaling in the developing lung, and underscore the critical importance of these key pathways in the pathogenesis of BPD. Future treatment strategies need to weigh the potential benefits of inhibiting pathologic cytokine expression against the potential of altering key developmental pathways.

Percutaneous minimal-access fetoscopic surgery for spina bifida aperta. Part II: maternal management and outcome

OBJECTIVE

To assess maternal morbidity and outcome in women undergoing minimal-access fetoscopic surgery for spina bifida aperta.

METHODS

This was a retrospective study of 51 women undergoing minimal-access fetoscopic surgery to improve postnatal neurological outcome of spina bifida aperta, at a mean gestational age of 24 weeks, at our center between July 2010 and June 2013. We analyzed various perioperative complications of surgery, namely: maternal and fetal death, need for maternal blood transfusion, placental abruption, pulmonary edema, spontaneous labor, oligohydramnios, chorioamnionitis, chorioamniotic membrane separation, duration of hospitalization, amniotic fluid leakage, gestational age at delivery and status of hysterotomy site.

RESULTS

In none of the 51 women was there maternal demise, spontaneous labor, placental abruption or a need for maternal blood transfusion in the perioperative period. Chorioamniotic membrane separation occurred in one patient, mild pulmonary edema occurred in one and oligohydramnios occurred in seven. All fetuses survived surgery, but there was one very early preterm delivery 1 week after the procedure and this neonate died immediately, from early postoperative chorioamnionitis. Amniotic fluid leakage occurred in 43 patients, at a mean gestational age of 29.7 (range, 22.6-37.3) weeks; two of these patients developed chorioamnionitis. Duration of maternal hospitalization after surgery was 7.2 (range, 4-12) days. Mean gestational age at delivery was 33 (range, 24.6-38.1) weeks. All abdominal and uterine trocar insertion sites healed well.

CONCLUSION

Minimal-access fetoscopic surgery for spina bifida aperta is apparently safe for most maternal patients. Despite the common occurrence of amniotic leakage, the majority of women deliver beyond 32 weeks of gestation.

Koinzidenzexperimente zur Untersuchung der Energieübertragung beim Stoß niederenergetischer Elektronen mit Molekülen

Scattering experiments of 70 eV electrons from methane and n-heptane are described. The results, namely energy-loss spectra, and the energy and angular distributions of the ejected electrons of these molecules are compared with those of argon. A coincidence technique is used to determine the energy distributions of the probability for formation of the molecular ions. By subtraction of the distributions from the total energy-loss spectra, the distributions of the superexcited states are obtained. In the case of n-heptane, superexcited states are found up to 20 eV above the first ionization potential.

Die Streuung niederenergetischer Elektronen an Methan. Das zweite Ionisierungspotential

Measurements are made of the inelastic scattering of electrons from methane into large scattering angles. The results show the appearance of a collision process at 19.5 ± 0.2 eV. From the measured angular dependence of the differential scattering cross section, this collision process is identified as an optically forbidden transition. The classification of this transition (2 sa1 → 3 sa1) and a value of the second appearance potential of methane (between 23.5 and 24 eV) are deduced from analogous transitions in neon.

Die dissoziative Ionisation von N2, O2, H2O, CO2 und Äthan

Simultaneous analysis of e/m, the kinetic energies of the fragment ions, and their appearance potentials were made in order to separate dissoziative ionization processes according to the electronic states of the fragments. The energy dependencies of absolute total cross sections have been determined for three different processes leading to the formation of both energetic N+ and O+-ions from N2 resp. O2.

Chronic lung disease in the preterm infant. Lessons learned from animal models

Neonatal chronic lung disease, also known as bronchopulmonary dysplasia (BPD), is the most common complication of premature birth, affecting up to 30% of very low birth weight infants. Improved medical care has allowed for the survival of the most premature infants and has significantly changed the pathology of BPD from a disease marked by severe lung injury to the "new" form characterized by alveolar hypoplasia and impaired vascular development. However, increased patient survival has led to a paucity of pathologic specimens available from infants with BPD. This, combined with the lack of a system to model alveolarization in vitro, has resulted in a great need for animal models that mimic key features of the disease. To this end, a number of animal models have been created by exposing the immature lung to injuries induced by hyperoxia, mechanical stretch, and inflammation and most recently by the genetic modification of mice. These animal studies have 1) allowed insight into the mechanisms that determine alveolar growth, 2) delineated factors central to the pathogenesis of neonatal chronic lung disease, and 3) informed the development of new therapies. In this review, we summarize the key findings and limitations of the most common animal models of BPD and discuss how knowledge obtained from these studies has informed clinical care. Future studies should aim to provide a more complete understanding of the pathways that preserve and repair alveolar growth during injury, which might be translated into novel strategies to treat lung diseases in infants and adults.

Activation of DNA damage response by antitumor therapy counteracts the activity of vinca alkaloids

BACKGROUND/AIM

Anthracyclines have been proven able to reduce the activity of vinca alkaloids by induction of cell-cycle arrest. The present study aims at identifying the critical initiation steps of signal transduction which transduce the inhibitory effects on the cytotoxicity of vinca alkaloids.

MATERIALS AND METHODS

Several new cytostatic drug classes were evaluated together with vincristine in tumor cell lines and patients' tumor cells. RNA interference was used for molecular analyses.

RESULTS

Inhibition of vincristine was observed by all cytostatic drugs, which induced cell-cycle arrest. Knockdown of proteins of the DNA damage response ascribed the inhibitory effect to a common pathway involving Chk-1, p53 and p21. Upstream of Chk-1 signal transduction depended on both ATM and ATR for all drugs except methotrexate.

CONCLUSION

We have identified critical signaling steps of the DNA damage response system activated by cytostatic drugs, which reduce the anti-tumor activity of vinca alkaloids. The obtained results encourage the development of novel therapeutic strategies to prevent pathway interactions based on the molecular understanding of drug action and drug-drug interactions.

Enhanced anti-tumour effects of Vinca alkaloids given separately from cytostatic therapies

BACKGROUND AND PURPOSE

In polychemotherapy protocols, that is for treatment of neuroblastoma and Ewing sarcoma, Vinca alkaloids and cell cycle-arresting drugs are usually administered on the same day. Here we studied whether this combination enables the optimal antitumour effects of Vinca alkaloids to be manifested.

EXPERIMENTAL APPROACH

Vinca alkaloids were tested in a preclinical mouse model in vivo and in vitro in combination with cell cycle-arresting drugs. Signalling pathways were characterized using RNA interference.

KEY RESULTS

In vitro, knockdown of cyclins significantly inhibited vincristine-induced cell death indicating, in accordance with previous findings, Vinca alkaloids require active cell cycling and M-phase transition for induction of cell death. In contrast, anthracyclines, irradiation and dexamethasone arrested the cell cycle and acted like cytostatic drugs. The combination of Vinca alkaloids with cytostatic therapeutics resulted in diminished cell death in 31 of 36 (86%) tumour cell lines. In a preclinical tumour model, anthracyclines significantly inhibited the antitumour effect of Vinca alkaloids in vivo. Antitumour effects of Vinca alkaloids in the presence of cytostatic drugs were restored by caffeine, which maintained active cell cycling, or by knockdown of p53, which prevented drug-induced cell cycle arrest. Therapeutically most important, optimal antitumour effects were obtained in vivo upon separating the application of Vinca alkaloids from cytostatic therapeutics.

CONCLUSION AND IMPLICATIONS

Clinical trials are required to prove whether Vinca alkaloids act more efficiently in cancer patients if they are applied uncoupled from cytostatic therapies. On a conceptual level, our data suggest the implementation of polychemotherapy protocols based on molecular mechanisms of drug-drug interactions.

LINKED ARTICLE

This article is commented on by Solary, pp 1555-1557 of this issue. To view this commentary visit http://dx.doi.org/10.1111/bph.12101.

In vivo imaging enables high resolution preclinical trials on patients' leukemia cells growing in mice

Background

Xenograft mouse models represent helpful tools for preclinical studies on human tumors. For modeling the complexity of the human disease, primary tumor cells are by far superior to established cell lines. As qualified exemplary model, patients’ acute lymphoblastic leukemia cells reliably engraft in mice inducing orthotopic disseminated leukemia closely resembling the disease in men. Unfortunately, disease monitoring of acute lymphoblastic leukemia in mice is hampered by lack of a suitable readout parameter.

Design and Methods

Patients’ acute lymphoblastic leukemia cells were lentivirally transduced to express the membrane-bound form of Gaussia luciferase. In vivo imaging was established in individual patients’ leukemias and extensively validated.

Results

Bioluminescence in vivo imaging enabled reliable and continuous follow-up of individual mice. Light emission strictly correlated to post mortem quantification of leukemic burden and revealed a logarithmic, time and cell number dependent growth pattern. Imaging conveniently quantified frequencies of leukemia initiating cells in limiting dilution transplantation assays. Upon detecting a single leukemia cell within more than 10,000 bone marrow cells, imaging enabled monitoring minimal residual disease, time to tumor re-growth and relapse. Imaging quantified therapy effects precisely and with low variances, discriminating treatment failure from partial and complete responses.

Conclusions

For the first time, we characterized in detail how in vivo imaging reforms preclinical studies on patient-derived tumors upon increasing monitoring resolution. In the future, in vivo imaging will enable performing precise preclinical studies on a broad range of highly demanding clinical challenges, such as treatment failure, resistance in leukemia initiating cells, minimal residual disease and relapse.

Glucocorticoids augment survival and proliferation of tumor cells

BACKGROUND

Glucocorticoids are widely used for cancer patients, although they can reduce the efficacy of anticancer treatment.

MATERIALS AND METHODS

We characterized non-apoptotic actions of glucocorticoids on tumor cell lines, primary tumor cells and an in vivo model, together with molecular signaling studies.

RESULTS

Glucocorticoids enhanced cell proliferation in 9/17 cell lines and significantly promoted tumor cell proliferation in a pre-clinical mouse model of lung carcinoma. 65/139 primary acute childhood leukemia samples were glucocorticoid-resistant. Both dexamethasone and prednisolone increased in vitro survival in 21/65 samples from glucocorticoid-resistant primary leukemias, revealing a completely new action of glucocorticoids. Dexamethasone-induced proliferation was mediated by glucocorticoid receptor and activated the proliferation signaling pathways of protein kinase B/AKT and p38 mitogen-activated protein kinase.

CONCLUSION

Our data suggest that restriction of the use of glucocorticoids during anticancer treatment might improve the outcome of patients with solid tumors.

NOXA as critical mediator for drug combinations in polychemotherapy

During polychemotherapy, cytotoxic drugs are given in combinations to enhance their anti-tumor effectiveness. For most drug combinations, underlying signaling mechanisms responsible for positive drug-drug interactions remain elusive. Here, we prove a decisive role for the Bcl-2 family member NOXA to mediate cell death by certain drug combinations, even if drugs were combined which acted independently from NOXA, when given alone. In proof-of-principle studies, betulinic acid, doxorubicin and vincristine induced cell death in a p53- and NOXA-independent pathway involving mitochondrial pore formation, release of cytochrome c and caspase activation. In contrast, when betulinic acid was combined with either doxorubicine or vincristine, cell death signaling changed considerably; the drug combinations clearly depended on both p53 and NOXA. Similarly and of high clinical relevance, in patient-derived childhood acute leukemia samples the drug combinations, but not the single drugs depended on p53 and NOXA, as shown by RNA interference studies in patient-derived cells. Our data emphasize that NOXA represents an important target molecule for combinations of drugs that alone do not target NOXA. NOXA might have a special role in regulating apoptosis sensitivity in the complex interplay of polychemotherapy. Deciphering the differences in signaling of single drugs and drug combinations might enable designing highly effective novel polychemotherapy regimens.