Pediatric lung disease: from proteinases to pulmonary fibrosis

Estimating the effect of nintedanib on forced vital capacity in children and adolescents with fibrosing interstitial lung disease using a Bayesian dynamic borrowing approach

BACKGROUND

The rarity of childhood interstitial lung disease (chILD) makes it challenging to conduct powered trials. In the InPedILD trial, among 39 children and adolescents with fibrosing ILD, there was a numerical benefit of nintedanib versus placebo on change in forced vital capacity (FVC) over 24 weeks (difference in mean change in FVC % predicted of 1.21 [95% confidence interval: -3.40, 5.81]). Nintedanib has shown a consistent effect on FVC across populations of adults with different diagnoses of fibrosing ILD.

METHODS

In a Bayesian dynamic borrowing analysis, prespecified before data unblinding, we incorporated data on the effect of nintedanib in adults and the data from the InPedILD trial to estimate the effect of nintedanib on FVC in children and adolescents with fibrosing ILD. The data from adults were represented as a meta-analytic predictive (MAP) prior distribution with mean 1.69 (95% credible interval: 0.49, 3.08). The adult data were weighted according to expert judgment on their relevance to the efficacy of nintedanib in chILD, obtained in a formal elicitation exercise.

RESULTS

Combined data from the MAP prior and InPedILD trial analyzed within the Bayesian framework resulted in a median difference between nintedanib and placebo in change in FVC % predicted at Week 24 of 1.63 (95% credible interval: -0.69, 3.40). The posterior probability for superiority of nintedanib versus placebo was 95.5%, reaching the predefined success criterion of at least 90%.

CONCLUSION

These findings, together with the safety data from the InPedILD trial, support the use of nintedanib in children and adolescents with fibrosing ILDs.

Chinese Medical Injections for Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Network Meta-analysis

BACKGROUND

The World Health Organization has indicated that chronic obstructive pulmonary disease (COPD) may become the third leading cause of death by 2030. Acute exacerbation of COPD (AECOPD) is an important process in clinical treatment. Recent studies have shown that Chinese medical injections (CMI) are effective against AECOPD, but the effective difference among different CMIs remains unclear. The aim of this network meta-analysis (NMA) is to compare the therapeutic effect of various CMIs.

METHODS

We conducted an overall, systematic literature search in the China National Knowledge Infrastructure, Wanfang, VIP, SinoMed, PubMed, Embase, Cochrane Library, and Web of Science databases to retrieve randomized controlled trials (RCTs) of CMIs for AECOPD published up to January 2021. The Cochrane risk of bias tool was used to assess the risk of bias. Stata 13.1 and WinBUGS 14.3 were used for data analyses.

RESULTS

In total, 103 RCTs involving 8767 participants and 23 CMIs were included. The results indicated that among all treatments conventional Western medical therapy (WM) plus Dengzhanxixin injection (DZXX) led to the best improvement in the clinical efficacy and the ratio of forced expiratory volume in one second (FEV1) to forced vital capacity (FVC) (FEV1/FVC), with surface under the cumulative ranking curve (SUCRA)=80.47% and 98.55%, respectively. Moreover, Shenmai injection (SM) plus WM and Reduning injection (RDN) plus WM led to the best improvement in the FEV1 (SUCRA=80.18%) and the ratio of forced expiratory volume in one second to the predicted value (FEV1%, SUCRA=87.28%). Shengmai injection (SGM) plus WM led to the most considerable shortening in the length of hospital stay (SUCRA=94.70%). Cluster analysis revealed that WM+DZXX had the most favorable response for clinical efficacy and FEV1, as well as clinical efficacy and FEV1/FVC, WM+RDN had the most favorable response for clinical efficacy and FEV1%, WM+SGM had the most favorable response for clinical efficacy and length of hospital stay.

CONCLUSION

WM+DZXX, WM+RDN, and WM+SGM were noted to be the optimum treatment regimens for improving in clinical efficacy, FEV1, FEV1/FVC, FEV1% and reducing the hospital stay length of AECOPD patients. Considering the limitations this NMA may have, the current results warrant further verification via additional high-quality studies.

Ground glass and fibrotic change in children with surfactant protein C dysfunction mutations

INTRODUCTION

Therapeutics exist to treat fibrotic lung disease in adults, but these have not been investigated in children. Defining biomarkers for pediatric fibrotic lung disease in children is crucial for clinical trials. Children with surfactant protein C (SFTPC) dysfunction mutations develop fibrotic lung disease over time. We evaluated chest computed tomography (CT) changes over time in children with SFTPC dysfunction mutations.

METHODS

We performed an institutional review board-approved retrospective review of children with SFTPC dysfunction mutations. We collected demographic and clinical information. Chest CT scans were evaluated using visual and computerized scores. Chest CT scores and pulmonary function tests were reviewed.

RESULTS

Eleven children were included. All children presented in infancy and four children suffered from respiratory failure requiring mechanical ventilation. Those who performed pulmonary function tests had stable forced vital capacities over time by percent predicted, but increased forced vital capacity in liters. CT findings evolved over time in most patients with earlier CT scans demonstrating ground glass opacities and later CT scans with more fibrotic features. In a pilot analysis, data-driven textural analysis software identified fibrotic features in children with SFTPC dysfunction that increased over time and correlated with visual CT scores.

DISCUSSION

We describe 11 children with SFTPC dysfunction mutations. Increases in forced vital capacity over time suggest that these children experience lung growth and that therapeutic intervention may maximize lung growth. Ground glass opacities are the primary early imaging findings while fibrotic features dominate later. CT findings suggest the development of and increases in fibrotic features that may serve as potential biomarkers for antifibrotic therapeutic trials.

Efficacy of YAP1-gene Knockdown to Inhibit Alveolar-Epithelial-Cell Senescence and Alleviate Idiopathic Pulmonary Fibrosis (IPF)

BACKGROUND/AIM

The prevalence of idiopathic pulmonary fibrosis (IPF) increases with age and is associated with senescence of alveolar epithelial cells (AECs). AEC senescence in pulmonary cells mediates IPF. We herein aimed to determine if YAP1 gene knockdown, a member of the Hippo/YAP signal pathway, in the bleomycin (BLM)-induced mouse model of IPF, inhibits onset of senescence of AECs and alleviates IPF.

MATERIALS AND METHODS

Adeno-associated viruses (AAVs) expressing Yes-associated protein 1 (YAP1) short hairpin RNA (shRNA) were delivered into the lung of BLM-induced IPF mice via intratracheal injection, to knockdown the YAP1 gene in AECs. The mice were assigned to 4 groups: G1: control (normal mice); G2: IPF mice; G3: IPF + AAV/YAP1; G4: IPF + AAV/scramble. After 28 days, AECs were examined for senescence using H&E staining, Masson's trichrome Staining, senescence-associated ß-galactosidase (SA-β-gal) staining, western blotting and co-immunofluorescence staining, to determine the expression of YAP1, Smad-3 and p21, in order to determine the induction of senescence of ACEs.

RESULTS

The severity of IPF determined by H&E staining, Masson's staining and immunofluorescence (IF) staining was positively correlated with the senescence of AECs. Down-regulation of YAP1 expression of the Hippo-signaling pathway, determined by western blotting in AECs, alleviated pulmonary fibrosis as determined by Masson's staining. Down regulation of YAP1 expression reduced the senescence of AECs as determined by ß-galactosidase (SA-β-gal) staining, which alleviated the clinical symptoms of IPF mice, as determined by body weight and lung index.

CONCLUSION

Down-regulation of YAP1 expression in AECs inhibited AEC senescence which is thought to be the cause of IPF. Therefore, future studies can focus on inhibiting YAP1 to effectively treat IPF.

YAP/TAZ affects the development of pulmonary fibrosis by regulating multiple signaling pathways

YAP and TAZ are important co-activators of various biological processes in human body. YAP/TAZ plays a vital role in the development of pulmonary fibrosis. Dysregulation of the YAP/TAZ signaling pathway is one of the most important causes of pulmonary fibrosis. Therefore, considering its crucial role, summary of the signal mechanism of YAP/TAZ is of certain guiding significance for the research of YAP/TAZ as a therapeutic target. The present review provided a detailed introduction to various YAP/TAZ-related signaling pathways and clarified the specific role of YAP/TAZ in these pathways. In the meantime, we summarized and evaluated possible applications of YAP/TAZ in the treatment of pulmonary fibrosis. Overall, our study is of guiding significance for future research on the functional mechanism of YAP/TAZ underlying lung diseases as well as for identification of novel therapeutic targets specific to pulmonary fibrosis.

Induction of tissue factor by urokinase in lung epithelial cells and in the lungs

RATIONALE

Urokinase-type plasminogen activator (uPA) regulates extracellular proteolysis in lung injury and repair. Although alveolar expression of uPA increases, procoagulant activity predominates.

OBJECTIVES

This study was designed to investigate whether uPA alters the expression of tissue factor (TF), the major initiator of the coagulation cascade, in lung epithelial cells (ECs).

METHODS

Bronchial, primary airway ECs and C57B6 wild-type, uPA-deficient (uPA(-/-)) mice were exposed to phosphate-buffered saline, uPA, or LPS. Immunohistochemistry, protein, cellular, and molecular techniques were used to assess TF expression and activity.

MEASUREMENTS AND MAIN RESULTS

uPA enhanced TF mRNA and protein expression, and TF-dependent coagulation in lung ECs. uPA-induced expression of TF involves both increased synthesis and enhanced stabilization of TF mRNA. uPA catalytic activity had little effect on induction of TF. By contrast, deletion of the uPA receptor binding growth factor domain from uPA markedly attenuated the induction of TF, suggesting that uPA receptor binding is sufficient for TF induction. Lung tissues of uPA-deficient mice expressed less TF protein and mRNA compared with wild-type mice. In addition, intratracheal instillation of mouse uPA increased TF mRNA and protein expression and accelerated coagulation in lung tissues. uPA(-/-) mice exposed to LPS failed to induce TF.

CONCLUSIONS

uPA increased TF expression and TF-dependent coagulation in the lungs of mice. We hypothesize that uPA-mediated induction of TF occurs in lung ECs to promote increased fibrin deposition in the airways during acute lung injury.

Clinical and genetic aspects of primary ciliary dyskinesia/Kartagener syndrome

Primary ciliary dyskinesia is a genetically heterogeneous disorder of motile cilia. Most of the disease-causing mutations identified to date involve the heavy (dynein axonemal heavy chain 5) or intermediate(dynein axonemal intermediate chain 1) chain dynein genes in ciliary outer dynein arms, although a few mutations have been noted in other genes. Clinical molecular genetic testing for primary ciliary dyskinesia is available for the most common mutations. The respiratory manifestations of primary ciliary dyskinesia (chronic bronchitis leading to bronchiectasis, chronic rhino-sinusitis, and chronic otitis media)reflect impaired mucociliary clearance owing to defective axonemal structure. Ciliary ultrastructural analysis in most patients (>80%) reveals defective dynein arms, although defects in other axonemal components have also been observed. Approximately 50% of patients with primary ciliary dyskinesia have laterality defects (including situs inversus totalis and, less commonly, heterotaxy, and congenital heart disease),reflecting dysfunction of embryological nodal cilia. Male infertility is common and reflects defects in sperm tail axonemes. Most patients with primary ciliary dyskinesia have a history of neonatal respiratory distress, suggesting that motile cilia play a role in fluid clearance during the transition from a fetal to neonatal lung. Ciliopathies involving sensory cilia, including autosomal dominant or recessive polycystic kidney disease, Bardet-Biedl syndrome, and Alstrom syndrome, may have chronic respiratory symptoms and even bronchiectasis suggesting clinical overlap with primary ciliary dyskinesia.

Nitric oxide attenuates epithelial-mesenchymal transition in alveolar epithelial cells

Patients with interstitial lung diseases, such as idiopathic pulmonary fibrosis (IPF) and bronchopulmonary dysplasia (BPD), suffer from lung fibrosis secondary to myofibroblast-mediated excessive ECM deposition and destruction of lung architecture. Transforming growth factor (TGF)-β1 induces epithelial-mesenchymal transition (EMT) of alveolar epithelial cells (AEC) to myofibroblasts both in vitro and in vivo. Inhaled nitric oxide (NO) attenuates ECM accumulation, enhances lung growth, and decreases alveolar myofibroblast number in experimental models. We therefore hypothesized that NO attenuates TGF-β1-induced EMT in cultured AEC. Studies of the capacity for endogenous NO production in AEC revealed that endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) are expressed and active in AEC. Total NOS activity was 1.3 pmol·mg protein−1·min−1 with 67% derived from eNOS. TGF-β1 (50 pM) suppressed eNOS expression by more than 60% and activity by 83% but did not affect iNOS expression or activity. Inhibition of endogenous NOS with l-NAME led to spontaneous EMT, manifested by increased α-smooth muscle actin (α-SMA) expression and a fibroblast-like morphology. Provision of exogenous NO to TGF-β1-treated AEC decreased stress fiber-associated α-SMA expression and decreased collagen I expression by 80%. NO-treated AEC also retained an epithelial morphology and expressed increased lamellar protein, E-cadherin, and pro-surfactant protein B compared with those treated with TGF-β alone. These findings indicate that NO serves a critical role in preserving an epithelial phenotype and in attenuating EMT in AEC. NO-mediated regulation of AEC fate may have important implications in the pathophysiology and treatment of diseases such as IPF and BPD.

Cigarette smoke exposure inhibits extracellular MMP-2 (gelatinase A) activity in human lung fibroblasts

Background

Exposure to cigarette smoke is considered a major risk factor for the development of lung diseases, since its causative role has been assessed in the induction and maintenance of an inflamed state in the airways. Lung fibroblasts can contribute to these processes, due to their ability to produce proinflammatory chemotactic molecules and extracellular matrix remodelling proteinases. Among proteolytic enzymes, gelatinases A and B have been studied for their role in tissue breakdown and mobilisation of matrix-derived signalling molecules. Multiple reports linked gelatinase deregulation and overexpression to the development of inflammatory chronic lung diseases such as COPD.

Methods

In this study we aimed to determine variations in the gelatinolytic pattern of human lung fibroblasts (HFL-1 cell line) exposed to cigarette smoke extract (CSE). Gelatinolytic activity levels were determined by using gelatin zymography for the in-gel detection of the enzymes (proenzyme and activated forms), and the subsequent semi-quantitative densitometric evaluation of lytic bands. Expression of gelatinases was evaluated also by RT-PCR, zymography of the cell lysates and by western blotting.

Results

CSE exposure at the doses used (1–10%) did not exert any significant cytotoxic effects on fibroblasts. Zymographic analysis showed that CSE exposure resulted in a linear decrease of the activity of gelatinase A. Control experiments allowed excluding a direct inhibitory effect of CSE on gelatinases. Zymography of cell lysates confirmed the expression of MMP-2 in all conditions. Semi-quantitative evaluation of mRNA expression allowed assessing a reduced transcription of the enzyme, as well as an increase in the expression of TIMP-2. Statistical analyses showed that the decrease of MMP-2 activity in conditioned media reached the statistical significance (p = 0.0031 for 24 h and p = 0.0012 for 48 h), while correlation analysis showed that this result was independent from CSE cytotoxicity (p = 0.7833 for both exposures).

Conclusion

Present work describes for the first time that, apart well characterized proinflammatory responses, human lung fibroblasts may react to CSE with a significant reduction of extracellular MMP-2 lytic activity. Therefore, fibroblasts may actively participate to the alteration of the proteolysis/antiproteolysis balance, which reflects the defective repair of the extracellular matrix. Such event should provide a further contribution to the maintenance of the inflamed state in the lungs.