Effects of nintedanib on the microvascular architecture in a lung fibrosis model

The role of vasculature and angiogenesis in respiratory diseases

In European countries, nearly 10% of all hospital admissions are related to respiratory diseases, mainly chronic life-threatening diseases such as COPD, pulmonary hypertension, IPF or lung cancer. The contribution of blood vessels and angiogenesis to lung regeneration, remodeling and disease progression has been increasingly appreciated. The vascular supply of the lung shows the peculiarity of dual perfusion of the pulmonary circulation (vasa publica), which maintains a functional blood-gas barrier, and the bronchial circulation (vasa privata), which reveals a profiled capacity for angiogenesis (namely intussusceptive and sprouting angiogenesis) and alveolar-vascular remodeling by the recruitment of endothelial precursor cells. The aim of this review is to outline the importance of vascular remodeling and angiogenesis in a variety of non-neoplastic and neoplastic acute and chronic respiratory diseases such as lung infection, COPD, lung fibrosis, pulmonary hypertension and lung cancer.

Multiscale computational model predicts how environmental changes and drug treatments affect microvascular remodeling in fibrotic disease

Investigating the molecular, cellular, and tissue-level changes caused by disease, and the effects of pharmacological treatments across these biological scales, necessitates the use of multiscale computational modeling in combination with experimentation. Many diseases dynamically alter the tissue microenvironment in ways that trigger microvascular network remodeling, which leads to the expansion or regression of microvessel networks. When microvessels undergo remodeling in idiopathic pulmonary fibrosis (IPF), functional gas exchange is impaired due to loss of alveolar structures and lung function declines. Here, we integrated a multiscale computational model with independent experiments to investigate how combinations of biomechanical and biochemical cues in IPF alter cell fate decisions leading to microvascular remodeling. Our computational model predicted that extracellular matrix (ECM) stiffening reduced microvessel area, which was accompanied by physical uncoupling of endothelial cell (ECs) and pericytes, the cells that comprise microvessels. Nintedanib, an FDA-approved drug for treating IPF, was predicted to further potentiate microvessel regression by decreasing the percentage of quiescent pericytes while increasing the percentage of pericytes undergoing pericyte-myofibroblast transition (PMT) in high ECM stiffnesses. Importantly, the model suggested that YAP/TAZ inhibition may overcome the deleterious effects of nintedanib by promoting EC-pericyte coupling and maintaining microvessel homeostasis. Overall, our combination of computational and experimental modeling can explain how cell decisions affect tissue changes during disease and in response to treatments.

Investigation of miR-26b and miR-27b expressions and the effect of quercetin on fibrosis in experimental pulmonary fibrosis

In this study, investigation of the effects of Quercetin on Bleomycin-induced pulmonary fibrosis and fibrosis-associated molecules miR-26b and miR-27b was aimed. Control group was given 10% saline on the 0th day, and saline was administered for 21 days starting from the 8th day. Group 2 was given 50 mg/kg Quercetin for 21 days starting from the 8th day. Group 3 was given 10 mg/kg Bleomycin Sulfate on day 0, and sacrificed on the 22nd and 29th day. Group 4 was given 10 mg/kg Bleomycin Sulfate on the 0th day, and was given 50 mg/kg Quercetin for 14 days, and 21 days starting from day 8. Lung tissues were examined using light and electron microscopic, immunohistochemical and molecular biological methods. Injury groups revealed impaired alveolar structure, collagen accumulation and increased inflammatory cells in interalveolar septum. Fibrotic response was decreased and the alveolar structure was improved with Quercetin treatment. α-SMA expressions were higher in the injury groups, but lower in the treatment groups compared to the injury groups. E-cadherin expressions were decreased in the injury groups and showed stronger immunoreactivity in the treatment groups compared to the injury groups. miR-26b and miR-27b expressions were lower in the injury groups than the control groups, and higher in the treatment groups than the injury groups. Quercetin can be considered as a new treatment agent in the idiopathic pulmonary fibrosis, since it increases the expression levels of miR-26b and miR-27b which decrease in fibrosis, and has therapeutic effects on the histopathological changes.

The Preventive Effect of Endostar on Radiation-induced Pulmonary Fibrosis

BACKGROUND

Radiation-induced pulmonary fibrosis (RIPF) is a long-term complication of thoracic radiotherapy without effective treatment available.

OBJECTIVE

This study aimed to establish a RIPF mouse model and explore the therapeutic effects and mechanisms of recombinant human endostatin (Endostar).

METHODS

C57BL/6 mice received a 16-Gy dose of X-rays to the whole thorax with or without the administration of Endostar for 24 weeks.

RESULTS

Radiation-induced body weight loss was partially attenuated by Endostar (P<0.05). Endostar significantly reduced alveolar inflammation (P<0.05) and pulmonary fibrosis (P<0.001), as indicated by a decrease in the expression levels of collagen I and collagen IV in lung tissue (both P<0.001). Angiogenesis (as shown by CD31 immunohistochemistry) was also decreased (P<0.01). In irradiated mice, Endostar inhibited the transforming growth factor-β1 (TGF-β1)/drosophila mothers against the decapentaplegic 3 (Smad3)/extracellular regulated protein kinases (ERK) signaling pathway (all P<0.05). In vitro, Endostar treatment decreased the radiation-induced expression of TGF-β1, vascular endothelial growth factor (VEGF), p-Smad3, and p-ERK in alveolar epithelial cells and vascular endothelial cells (all P<0.05).

CONCLUSION

Endostar could alleviate RIPF through decreased antiangiogenic activity and inhibition of the TGF-β1/Smad3/ERK pathway.

Transluminal Pillars-Their Origin and Role in the Remodelling of the Zebrafish Caudal Vein Plexus

Intussusceptive pillars, regarded as a hallmark of intussusceptive angiogenesis, have been described in developing vasculature of many organs and organisms. The aim of this study was to resolve the question about pillar formation and their further maturation employing zebrafish caudal vein plexus (CVP). The CVP development was monitored by in vivo confocal microscopy in high spatio-temporal resolution using the transgenic zebrafish model Fli1a:eGPF//Gata1:dsRed. We tracked back the formation of pillars (diameter ≤ 4 µm) and intercapillary meshes (diameter > 4 µm) and analysed their morphology and behaviour. Transluminal pillars in the CVP arose via a combination of sprouting, lumen expansion, and/or the creation of intraluminal folds, and those mechanisms were not associated directly with blood flow. The follow-up of pillars indicated that one-third of them disappeared between 28 and 48 h post fertilisation (hpf), and of the remaining ones, only 1/17 changed their cross-section area by >50%. The majority of the bigger meshes (39/62) increased their cross-section area by >50%. Plexus simplification and the establishment of hierarchy were dominated by the dynamics of intercapillary meshes, which formed mainly via sprouting angiogenesis. These meshes were observed to grow, reshape, and merge with each other. Our observations suggested an alternative view on intussusceptive angiogenesis in the CVP.

A Protective Effect of Pirfenidone in Lung Fibroblast-Endothelial Cell Network via Inhibition of Rho-Kinase Activity

Pulmonary fibrosis is a life-threatening disease that has been attributed to several causes. Specifically, vascular injury is thought to be involved in the pathogenesis of fibrosis. The effects of the antifibrotic drug pirfenidone on angiogenesis have not been fully elucidated. This study aimed to investigate the effects of pirfenidone in human lung fibroblast-endothelial cell co-culture network formation and to analyze the underlying molecular mechanisms. Human lung fibroblasts were co-cultured with human umbilical vein endothelial cells to establish a co-culture network cell sheet. The influence of pirfenidone was evaluated for protective effect on the endothelial network in cell sheets stimulated with transforming growth factor β (TGF-β). Results indicated that TGF-β disrupted the network formation. Pirfenidone and Y27632 (Rho-associated coiled-coil containing protein kinase [Rho-kinase or ROCK] inhibitor) protected against the TGF-β-induced endothelial network disruption. TGF-β activated Rho-kinase signaling in cells composing the co-culture cell sheet, whereas pirfenidone and Y27632 inhibited these effects. In conclusion, TGF-β-induced Rho-kinase activation and disrupted endothelial network formation. Pirfenidone suppressed TGF-β-induced Rho-kinase activity in cell sheets, thereby enabling vascular endothelial cells networks to be preserved in the cell sheets. These findings suggest that pirfenidone has potential vascular network-preserving effect via inhibiting Rho-kinase activity in vascular injury, which is a precursor to pulmonary fibrosis.

Progress in understanding and treating idiopathic pulmonary fibrosis: recent insights and emerging therapies

Idiopathic pulmonary fibrosis (IPF) is a long-lasting, continuously advancing, and irrevocable interstitial lung disorder with an obscure origin and inadequately comprehended pathological mechanisms. Despite the intricate and uncharted causes and pathways of IPF, the scholarly consensus upholds that the transformation of fibroblasts into myofibroblasts-instigated by injury to the alveolar epithelial cells-and the disproportionate accumulation of extracellular matrix (ECM) components, such as collagen, are integral to IPF's progression. The introduction of two novel anti-fibrotic medications, pirfenidone and nintedanib, have exhibited efficacy in decelerating the ongoing degradation of lung function, lessening hospitalization risk, and postponing exacerbations among IPF patients. Nonetheless, these pharmacological interventions do not present a definitive solution to IPF, positioning lung transplantation as the solitary potential curative measure in contemporary medical practice. A host of innovative therapeutic strategies are presently under rigorous scrutiny. This comprehensive review encapsulates the recent advancements in IPF research, spanning from diagnosis and etiology to pathological mechanisms, and introduces a discussion on nascent therapeutic methodologies currently in the pipeline.

The endothelium in lung fibrosis: a core signaling hub in disease pathogenesis?

Pulmonary fibrosis (PF) is a progressive chronic lung disease characterized by excessive deposition of extracellular matrix (ECM) and structural destruction, associated with a severe 5-year mortality rate. The onset of the disease is thought to be triggered by chronic damage to the alveolar epithelium. Since the pulmonary endothelium is an important component of the alveolar-capillary niche, it is also affected by the initial injury. In addition to ensuring proper gas exchange, the endothelium has critical functional properties, including regulation of vascular tone, inflammatory responses, coagulation, and maintenance of vascular homeostasis and integrity. Recent single-cell analyses have shown that shifts in endothelial cell (EC) subtypes occur in PF. Furthermore, the increased vascular remodeling associated with PF leads to deteriorated outcomes for patients, underscoring the importance of the vascular bed in PF. To date, the causes and consequences of endothelial and vascular involvement in lung fibrosis are poorly understood. Therefore, it is of great importance to investigate the involvement of EC and the vascular system in the pathogenesis of the disease. In this review, we will outline the current knowledge on the role of the pulmonary vasculature in PF, in terms of abnormal cellular interactions, hyperinflammation, vascular barrier disorders, and an altered basement membrane composition. Finally, we will summarize recent advances in extensive therapeutic research and discuss the significant value of novel therapies targeting the endothelium.

Thalidomide interaction with inflammation in idiopathic pulmonary fibrosis

The "Thalidomide tragedy" is a landmark in the history of the pharmaceutical industry. Despite limited clinical trials, there is a continuous effort to investigate thalidomide as a drug for cancer and inflammatory diseases such as rheumatoid arthritis, lepromatous leprosy, and COVID-19. This review focuses on the possibilities of targeting inflammation by repurposing thalidomide for the treatment of idiopathic pulmonary fibrosis (IPF). Articles were searched from the Scopus database, sorted, and selected articles were reviewed. The content includes the proven mechanisms of action of thalidomide relevant to IPF. Inflammation, oxidative stress, and epigenetic mechanisms are major pathogenic factors in IPF. Transforming growth factor-β (TGF-β) is the major biomarker of IPF. Thalidomide is an effective anti-inflammatory drug in inhibiting TGF-β, interleukins (IL-6 and IL-1β), and tumour necrosis factor-α (TNF-α). Thalidomide binds cereblon, a process that is involved in the proposed mechanism in specific cancers such as breast cancer, colon cancer, multiple myeloma, and lung cancer. Cereblon is involved in activating AMP-activated protein kinase (AMPK)-TGF-β/Smad signalling, thereby attenuating fibrosis. The past few years have witnessed an improvement in the identification of biomarkers and diagnostic technologies in respiratory diseases, partly because of the COVID-19 pandemic. Hence, investment in clinical trials with a systematic plan can help repurpose thalidomide for pulmonary fibrosis.

Biological Hyperthermia-Inducing Nanoparticles for Specific Remodeling of the Extracellular Matrix Microenvironment Enhance Pro-Apoptotic Therapy in Fibrosis

The extracellular matrix (ECM) is a major driver of fibrotic diseases and forms a dense fibrous barrier that impedes nanodrug delivery. Because hyperthermia causes destruction of ECM components, we developed a nanoparticle preparation to induce fibrosis-specific biological hyperthermia (designated as GPQ-EL-DNP) to improve pro-apoptotic therapy against fibrotic diseases based on remodeling of the ECM microenvironment. GPQ-EL-DNP is a matrix metalloproteinase (MMP)-9-responsive peptide, (GPQ)-modified hybrid nanoparticle containing fibroblast-derived exosomes and liposomes (GPQ-EL) and is loaded with a mitochondrial uncoupling agent, 2,4-dinitrophenol (DNP). GPQ-EL-DNP can specifically accumulate and release DNP in the fibrotic focus, inducing collagen denaturation through biological hyperthermia. The preparation was able to remodel the ECM microenvironment, decrease stiffness, and suppress fibroblast activation, which further enhanced GPQ-EL-DNP delivery to fibroblasts and sensitized fibroblasts to simvastatin-induced apoptosis. Therefore, simvastatin-loaded GPQ-EL-DNP achieved an improved therapeutic effect on multiple types of murine fibrosis. Importantly, GPQ-EL-DNP did not induce systemic toxicity to the host. Therefore, the nanoparticle GPQ-EL-DNP for fibrosis-specific hyperthermia can be used as a potential strategy to enhance pro-apoptotic therapy in fibrotic diseases.

Injured Endothelial Cell: A Risk Factor for Pulmonary Fibrosis

The pathological features of pulmonary fibrosis (PF) are the abnormal activation and proliferation of myofibroblasts and the extraordinary deposition of the extracellular matrix (ECM). However, the pathogenesis of PF is still indistinct. In recent years, many researchers have realized that endothelial cells had a crucial role in the development of PF. Studies have demonstrated that about 16% of the fibroblasts in the lung tissue of fibrotic mice were derived from endothelial cells. Endothelial cells transdifferentiated into mesenchymal cells via the endothelial-mesenchymal transition (E(nd)MT), leading to the excessive proliferation of endothelial-derived mesenchymal cells and the accumulation of fibroblasts and ECM. This suggested that endothelial cells, a significant component of the vascular barrier, played an essential role in PF. Herein, this review discusses E(nd)MT and its contribution to the activation of other cells in PF, which could provide new ideas for further understanding the source and activation mechanism of fibroblasts and the pathogenesis of PF.

BIBF1120 Protects against Diabetic Retinopathy through Neovascularization-Related Molecules and the MAPK Signaling Pathway

Diabetic retinopathy (DR) is one of the microvascular complications of diabetes mellitus and a major pathological feature of neovascular DR. These patients potentially experience vision impairment and blindness. Platelet-derived growth factor receptor β (PDGFRβ), fibroblast growth factor receptor 1 (FGFR1), and vascular endothelial growth factor receptor 2 (VEGFR2) are implicated in the DR pathogenesis. Nintedanib (BIBF1120) is an oral selective dual receptor tyrosine kinase (RTK) inhibitor of VEGFR2, FGFR1, and PDGFRβ. In this study, intravitreal injection of BIBF1120 blocked the phosphorylation of VEGFR2, FGFR1, PDGFRβ, and MAPK signaling pathway proteins in a streptozotocin (STZ)-induced diabetic retinopathy mouse model. In in vitro cell experiments, BIBF1120 did not change cellular activity under normal conditions, while it further suppressed the tube formation, migration, and proliferation of high glucose-induced human retinal microvascular endothelial cells (HRMECs). Additionally, BIBF1120 blocked the phosphorylation of p38, JNK, and ERK1/2 in high glucose-treating HRMECs. Our results indicate that the BIBF1120 treatment can be a novel potential drug to protect against DR.

3D pulmonary fibrosis model for anti-fibrotic drug discovery by inkjet-bioprinting

Pulmonary fibrosis (PF) is known as a chronic and irreversible disease characterized by excessive extracellular matrix accumulation and lung architecture changes. Large efforts have been made to develop prospective treatments and study the etiology of pulmonary fibrotic diseases utilizing animal models and spherical organoids. As part of these efforts, we created an all-inkjet-printed three-dimensional (3D) alveolar barrier model that can be used for anti-fibrotic drug discovery. Then, we developed a PF model by treating the 3D alveolar barrier with pro-fibrotic cytokine and confirmed that it is suitable for the fibrosis model by observing changes in structural deposition, pulmonary function, epithelial-mesenchymal transition, and fibrosis markers. The model was tested with two approved anti-fibrotic drugs, and we could observe that the symptoms in the disease model were alleviated. Consequently, structural abnormalities and changes in mRNA expression were found in the induced fibrosis model, which were shown to be recovered in all drug treatment groups. The all-inkjet-printed alveolar barrier model was reproducible for disease onset and therapeutic effects in the human body. This finding emphasized that thein vitroartificial tissue with faithfully implemented 3D microstructures using bioprinting technology may be employed as a novel testing platform and disease model to evaluate potential drug efficacy.

Organ-on-a-chip: Its use in cardiovascular research

Organ-on-a-chip (OOAC) has attracted great attention during the last decade as a revolutionary alternative to conventional animal models. This cutting-edge technology has also brought constructive changes to the field of cardiovascular research. The cardiovascular system, especially the heart as a well-protected vital organ, is virtually impossible to replicate in vitro with conventional approaches. This made scientists assume that they needed to use animal models for cardiovascular research. However, the frequent failure of animal models to correctly reflect the native cardiovascular system necessitated a search for alternative platforms for preclinical studies. Hence, as a promising alternative to conventional animal models, OOAC technology is being actively developed and tested in a wide range of biomedical fields, including cardiovascular research. Therefore, in this review, the current literature on the use of OOACs for cardiovascular research is presented with a focus on the basis for using OOACs, and what has been specifically achieved by using OOACs is also discussed. By providing an overview of the current status of OOACs in cardiovascular research and its future perspectives, we hope that this review can help to develop better and optimized research strategies for cardiovascular diseases (CVDs) as well as identify novel applications of OOACs in the near future.

The fatal trajectory of pulmonary COVID-19 is driven by lobular ischemia and fibrotic remodelling

BACKGROUND

COVID-19 is characterized by a heterogeneous clinical presentation, ranging from mild symptoms to severe courses of disease. 9-20% of hospitalized patients with severe lung disease die from COVID-19 and a substantial number of survivors develop long-COVID. Our objective was to provide comprehensive insights into the pathophysiology of severe COVID-19 and to identify liquid biomarkers for disease severity and therapy response.

METHODS

We studied a total of 85 lungs (n = 31 COVID autopsy samples; n = 7 influenza A autopsy samples; n = 18 interstitial lung disease explants; n = 24 healthy controls) using the highest resolution Synchrotron radiation-based hierarchical phase-contrast tomography, scanning electron microscopy of microvascular corrosion casts, immunohistochemistry, matrix-assisted laser desorption ionization mass spectrometry imaging, and analysis of mRNA expression and biological pathways. Plasma samples from all disease groups were used for liquid biomarker determination using ELISA. The anatomic/molecular data were analyzed as a function of patients' hospitalization time.

FINDINGS

The observed patchy/mosaic appearance of COVID-19 in conventional lung imaging resulted from microvascular occlusion and secondary lobular ischemia. The length of hospitalization was associated with increased intussusceptive angiogenesis. This was associated with enhanced angiogenic, and fibrotic gene expression demonstrated by molecular profiling and metabolomic analysis. Increased plasma fibrosis markers correlated with their pulmonary tissue transcript levels and predicted disease severity. Plasma analysis confirmed distinct fibrosis biomarkers (TSP2, GDF15, IGFBP7, Pro-C3) that predicted the fatal trajectory in COVID-19.

INTERPRETATION

Pulmonary severe COVID-19 is a consequence of secondary lobular microischemia and fibrotic remodelling, resulting in a distinctive form of fibrotic interstitial lung disease that contributes to long-COVID.

FUNDING

This project was made possible by a number of funders. The full list can be found within the Declaration of interests / Acknowledgements section at the end of the manuscript.

Real-Time Measurement of Cell Mechanics as a Clinically Relevant Readout of an In Vitro Lung Fibrosis Model Established on a Bioinspired Basement Membrane

Lung fibrosis, one of the major post-COVID complications, is a progressive and ultimately fatal disease without a cure. Here, an organ- and disease-specific in vitro mini-lung fibrosis model equipped with noninvasive real-time monitoring of cell mechanics is introduced as a functional readout. To establish an intricate multiculture model under physiologic conditions, a biomimetic ultrathin basement (biphasic elastic thin for air-liquid culture conditions, BETA) membrane (<1 µm) is developed with unique properties, including biocompatibility, permeability, and high elasticity (<10 kPa) for cell culturing under air-liquid interface and cyclic mechanical stretch conditions. The human-based triple coculture fibrosis model, which includes epithelial and endothelial cell lines combined with primary fibroblasts from idiopathic pulmonary fibrosis patients established on the BETA membrane, is integrated into a millifluidic bioreactor system (cyclic in vitro cell-stretch, CIVIC) with dose-controlled aerosolized drug delivery, mimicking inhalation therapy. The real-time measurement of cell/tissue stiffness (and compliance) is shown as a clinical biomarker of the progression/attenuation of fibrosis upon drug treatment, which is confirmed for inhaled Nintedanib-an antifibrosis drug. The mini-lung fibrosis model allows the combined longitudinal testing of pharmacodynamics and pharmacokinetics of drugs, which is expected to enhance the predictive capacity of preclinical models and hence facilitate the development of approved therapies for lung fibrosis.

Evidence for the Benefits of Melatonin in Cardiovascular Disease

The pineal gland is a neuroendocrine gland which produces melatonin, a neuroendocrine hormone with critical physiological roles in the circadian rhythm and sleep-wake cycle. Melatonin has been shown to possess anti-oxidant activity and neuroprotective properties. Numerous studies have shown that melatonin has significant functions in cardiovascular disease, and may have anti-aging properties. The ability of melatonin to decrease primary hypertension needs to be more extensively evaluated. Melatonin has shown significant benefits in reducing cardiac pathology, and preventing the death of cardiac muscle in response to ischemia-reperfusion in rodent species. Moreover, melatonin may also prevent the hypertrophy of the heart muscle under some circumstances, which in turn would lessen the development of heart failure. Several currently used conventional drugs show cardiotoxicity as an adverse effect. Recent rodent studies have shown that melatonin acts as an anti-oxidant and is effective in suppressing heart damage mediated by pharmacologic drugs. Therefore, melatonin has been shown to have cardioprotective activity in multiple animal and human studies. Herein, we summarize the most established benefits of melatonin in the cardiovascular system with a focus on the molecular mechanisms of action.

Pivotal role of micro-CT technology in setting up an optimized lung fibrosis mouse model for drug screening

Idiopathic pulmonary fibrosis (IPF) is a progressive disease with no curative pharmacological treatment. The most used animal model of IPF for anti-fibrotic drug screening is bleomycin (BLM)-induced lung fibrosis. However, several issues have been reported: the balance among disease resolution, an appropriate time window for therapeutic intervention and animal welfare remain critical aspects yet to be fully elucidated. In this study, C57Bl/6 male mice were treated with BLM via oropharyngeal aspiration (OA) following either double or triple administration. The fibrosis progression was longitudinally assessed by micro-CT every 7 days for 4 weeks after BLM administration. Quantitative micro-CT measurements highlighted that triple BLM administration was the ideal dose regimen to provoke sustained lung fibrosis up to 28 days. These results were corroborated with lung histology and Bronchoalveolar Lavage Fluid cells. We have developed a mouse model with prolonged lung fibrosis enabling three weeks of a curative therapeutic window for the screening of putative anti-fibrotic drugs. Moreover, we have demonstrated the pivotal role of longitudinal micro-CT imaging in reducing the number of animals required per experiment in which each animal can be its own control. This approach permits a valuable decrease in costs and time to develop disease animal models.

Meta-Analysis of Effect of Nintedanib on Reducing FVC Decline Across Interstitial Lung Diseases

Introduction

The effect of nintedanib on slowing the rate of decline in forced vital capacity (FVC) has been investigated in randomized placebo-controlled trials in subjects with idiopathic pulmonary fibrosis (IPF), other progressive fibrosing interstitial lung diseases (ILDs), and ILD associated with systemic sclerosis (SSc-ILD). We assessed the consistency of the effect of nintedanib on the rate of decline in FVC over 52 weeks across four placebo-controlled phase III trials.

Methods

We used data on FVC decline from the INPULSIS-1 and INPULSIS-2 trials in subjects with IPF, the INBUILD trial in subjects with progressing fibrosing ILDs other than IPF, and the SENSCIS trial in subjects with SSc-ILD. In each trial, the primary endpoint was the annual rate of decline in FVC (mL/year) assessed over 52 weeks. We performed fixed effect and random effects meta-analyses based on the relative treatment effect of nintedanib versus placebo on the rate of decline in FVC (mL/year) over 52 weeks. Heterogeneity of the relative treatment effect of nintedanib across populations was assessed using the I² statistic, τ² and corresponding p value from a Q test for heterogeneity.

Results

The combined analysis comprised 1257 subjects treated with nintedanib and 1042 subjects who received placebo. Nintedanib reduced the rate of decline in FVC (mL/year) over 52 weeks by 51.0% (95% CI 39.1, 63.0) compared with placebo. The relative effect (95% CI) was the same using the fixed effect and random effects models. There was no evidence of heterogeneity in the relative treatment effect of nintedanib across the populations studied (I² = 0%, τ² = 0, p = 0.93).

Conclusions

A meta-analysis of data from four placebo-controlled trials demonstrated that nintedanib approximately halved the rate of decline in FVC over 52 weeks across subjects with different forms of pulmonary fibrosis, with no evidence of heterogeneity in its relative treatment effect across patient populations.

Graphical abstract

BI 1015550 is a PDE4B Inhibitor and a Clinical Drug Candidate for the Oral Treatment of Idiopathic Pulmonary Fibrosis

The anti-inflammatory and immunomodulatory abilities of oral selective phosphodiesterase 4 (PDE4) inhibitors enabled the approval of roflumilast and apremilast for use in chronic obstructive pulmonary disease and psoriasis/psoriatic arthritis, respectively. However, the antifibrotic potential of PDE4 inhibitors has not yet been explored clinically. BI 1015550 is a novel PDE4 inhibitor showing a preferential enzymatic inhibition of PDE4B. In vitro, BI 1015550 inhibits lipopolysaccharide (LPS)-induced tumor necrosis factor-α (TNF-α) and phytohemagglutinin-induced interleukin-2 synthesis in human peripheral blood mononuclear cells, as well as LPS-induced TNF-α synthesis in human and rat whole blood. In vivo, oral BI 1015550 shows potent anti-inflammatory activity in mice by inhibiting LPS-induced TNF-α synthesis ex vivo and in Suncus murinus by inhibiting neutrophil influx into bronchoalveolar lavage fluid stimulated by nebulized LPS. In Suncus murinus, PDE4 inhibitors induce emesis, a well-known gastrointestinal side effect limiting the use of PDE4 inhibitors in humans, and the therapeutic ratio of BI 1015550 appeared to be substantially improved compared with roflumilast. Oral BI 1015550 was also tested in two well-known mouse models of lung fibrosis (induced by either bleomycin or silica) under therapeutic conditions, and appeared to be effective by modulating various model-specific parameters. To better understand the antifibrotic potential of BI 1015550 in vivo, its direct effect on human fibroblasts from patients with idiopathic pulmonary fibrosis (IPF) was investigated in vitro. BI 1015550 inhibited transforming growth factor-β-stimulated myofibroblast transformation and the mRNA expression of various extracellular matrix proteins, as well as basic fibroblast growth factor plus interleukin-1β-induced cell proliferation. Nintedanib overall was unremarkable in these assays, but interestingly, the inhibition of proliferation was synergistic when it was combined with BI 1015550, leading to a roughly 10-fold shift of the concentration–response curve to the left. In summary, the unique preferential inhibition of PDE4B by BI 1015550 and its anticipated improved tolerability in humans, plus its anti-inflammatory and antifibrotic potential, suggest BI 1015550 to be a promising oral clinical candidate for the treatment of IPF and other fibro-proliferative diseases.

Time-Dependent Molecular Motifs of Pulmonary Fibrogenesis in COVID-19

(1) Background: In COVID-19 survivors there is an increased prevalence of pulmonary fibrosis of which the underlying molecular mechanisms are poorly understood; (2) Methods: In this multicentric study, n = 12 patients who succumbed to COVID-19 due to progressive respiratory failure were assigned to an early and late group (death within ≤7 and >7 days of hospitalization, respectively) and compared to n = 11 healthy controls; mRNA and protein expression as well as biological pathway analysis were performed to gain insights into the evolution of pulmonary fibrogenesis in COVID-19; (3) Results: Median duration of hospitalization until death was 3 (IQR25-75, 3–3.75) and 14 (12.5–14) days in the early and late group, respectively. Fifty-eight out of 770 analyzed genes showed a significantly altered expression signature in COVID-19 compared to controls in a time-dependent manner. The entire study group showed an increased expression of BST2 and IL1R1, independent of hospitalization time. In the early group there was increased activity of inflammation-related genes and pathways, while fibrosis-related genes (particularly PDGFRB) and pathways dominated in the late group; (4) Conclusions: After the first week of hospitalization, there is a shift from pro-inflammatory to fibrogenic activity in severe COVID-19. IL1R1 and PDGFRB may serve as potential therapeutic targets in future studies.

Fatty acid nitroalkene reversal of established lung fibrosis

Tissue fibrosis occurs in response to dysregulated metabolism, pro-inflammatory signaling and tissue repair reactions. For example, lungs exposed to environmental toxins, cancer therapies, chronic inflammation and other stimuli manifest a phenotypic shift to activated myofibroblasts and progressive and often irreversible lung tissue scarring. There are no therapies that stop or reverse fibrosis. The 2 FDA-approved anti-fibrotic drugs at best only slow the progression of fibrosis in humans. The present study was designed to test whether a small molecule electrophilic nitroalkene, nitro-oleic acid (NO₂-OA), could reverse established pulmonary fibrosis induced by the intratracheal administration of bleomycin in C57BL/6 mice. After 14 d of bleomycin-induced fibrosis development in vivo, lungs were removed, sectioned and precision-cut lung slices (PCLS) from control and bleomycin-treated mice were cultured ex vivo for 4 d with either vehicle or NO₂-OA (5 μM). Biochemical and morphological analyses showed that over a 4 d time frame, NO₂-OA significantly inhibited pro-inflammatory mediator and growth factor expression and reversed key indices of fibrosis (hydroxyproline, collagen 1A1 and 3A1, fibronectin-1). Quantitative image analysis of PCLS immunohistology reinforced these observations, revealing that NO₂-OA suppressed additional hallmarks of the fibrotic response, including alveolar epithelial cell loss, myofibroblast differentiation and proliferation, collagen and α-smooth muscle actin expression. NO₂-OA also accelerated collagen degradation by resident macrophages. These effects occurred in the absence of the recognized NO₂-OA modulation of circulating and migrating immune cell activation. Thus, small molecule nitroalkenes may be useful agents for reversing pathogenic fibrosis of lung and other organs.

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Small molecule electrophiles, pleiotropic anti-inflammatory and anti-fibrotic drugs.

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NO₂-OA inhibits activated myofibroblasts, induces dedifferentiation to fibroblasts.

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NO₂-OA activates extracellular matrix degradation by macrophages.

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NO₂-OA promotes proliferation of alveolar type 1 and 2 epithelial cells.

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NO₂-OA reverses established lung fibrosis in murine lung slices.

Animal models of drug-induced pulmonary fibrosis: an overview of molecular mechanisms and characteristics

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease characterized by progressive loss of pulmonary function. Drug-induced interstitial lung disease has been reported as a severe adverse effect of some drugs, such as bleomycin, amiodarone, and methotrexate. Based on good characteristics, drug-induced pulmonary fibrosis (PF) animal model has played a key role in our understanding of the molecular mechanisms of PF pathogenesis and recapitulates the specific pathology in patients and helps develop therapeutic strategies. Here, we summarize the mechanisms and characteristics of given fibrotic drug-induced animal models for PFs. Together with the key publications describing these models, this brief but detailed overview would be helpful for the pharmacological research with animal models of PFs. Potential mechanisms underlying drug induced lung toxicity.

Ion therapy of pulmonary fibrosis by inhalation of ionic solution derived from silicate bioceramics

Pulmonary fibrosis (PF) is a chronic and progressively fatal disease, but clinically available therapeutic drugs are limited due to efficacy and side effects. The possible mechanism of pulmonary fibrosis includes the damage of alveolar epithelial cells II (AEC2), and activation of immune cells such as macrophages. The ions released from bioceramics have shown the activity in stimulating soft tissue derived cells such as fibroblasts, endothelia cells and epithelia cells, and regulating macrophage polarization. Therefore, this study proposes an "ion therapy" approach based on the active ions of bioceramic materials, and investigates the therapeutic effect of bioactive ions derived from calcium silicate (CS) bioceramics on mouse models of pulmonary fibrosis. We demonstrate that silicate ions significantly reduce pulmonary fibrosis by simultaneously regulating the functions of AEC2 and macrophages. This result suggests potential clinical applications of ion therapy for lung fibrosis.

Hierarchical imaging and computational analysis of three-dimensional vascular network architecture in the entire postnatal and adult mouse brain

The formation of new blood vessels and the establishment of vascular networks are crucial during brain development, in the adult healthy brain, as well as in various diseases of the central nervous system. Here, we describe a step-by-step protocol for our recently developed method that enables hierarchical imaging and computational analysis of vascular networks in postnatal and adult mouse brains. The different stages of the procedure include resin-based vascular corrosion casting, scanning electron microscopy, synchrotron radiation and desktop microcomputed tomography imaging, and computational network analysis. Combining these methods enables detailed visualization and quantification of the 3D brain vasculature. Network features such as vascular volume fraction, branch point density, vessel diameter, length, tortuosity and directionality as well as extravascular distance can be obtained at any developmental stage from the early postnatal to the adult brain. This approach can be used to provide a detailed morphological atlas of the entire mouse brain vasculature at both the postnatal and the adult stage of development. Our protocol allows the characterization of brain vascular networks separately for capillaries and noncapillaries. The entire protocol, from mouse perfusion to vessel network analysis, takes ~10 d.

Nintedanib ameliorates imiquimod-induced psoriasis in mice by inhibiting NF-κB and VEGFR2 signaling

Psoriasis is a common chronic skin disorder characterized by keratinocyte hyperproliferation with altered differentiation accompanied by increased inflammation and angiogenesis. Nintedanib is a tyrosine kinase inhibitor that has anti-inflammatory, anti-angiogenesis, and anti-fibrotic effects. In this study, we explored the potential effects and mechanisms of nintedanib on psoriasis in vivo and in vitro. In vivo experiments showed that nintedanib effectively alleviated imiquimod-induced psoriasis-like skin lesions and reduced psoriasis severity index scores. For the mechanism research, we mainly focused on the abnormal phenotype of keratinocyte in the pathogenesis of psoriasis. We used HaCaT cells in the in vitro experiments and the result revealed that nintedanib restored keratinocyte homeostasis by downregulated the expression of proinflammatory factors, inhibited hyperproliferation, promoted apoptosis, maintained normal differentiation via regulating the NF-κB pathway. In addition, nintedanib regulated angiogenesis by inhibiting VEGFR2 activity. In summary, our study indicated that nintedanib is a promising candidate medication for psoriatic treatment.

SSC-ILD mouse model induced by osmotic minipump delivered bleomycin: effect of Nintedanib

Systemic sclerosis (SSc) is an autoimmune disease characterized by an excessive production and accumulation of collagen in the skin and internal organs often associated with interstitial lung disease (ILD). Its pathogenetic mechanisms are unknown and the lack of animal models mimicking the features of the human disease is creating a gap between the selection of anti-fibrotic drug candidates and effective therapies. In this work, we intended to pharmacologically validate a SSc-ILD model based on 1 week infusion of bleomycin (BLM) by osmotic minipumps in C57/BL6 mice, since it will serve as a tool for secondary drug screening. Nintedanib (NINT) has been used as a reference compound to investigate antifibrotic activity either for lung or skin fibrosis. Longitudinal Micro-CT analysis highlighted a significant slowdown in lung fibrosis progression after NINT treatment, which was confirmed by histology. However, no significant effect was observed on lung hydroxyproline content, inflammatory infiltrate and skin lipoatrophy. The modest pharmacological effect reported here could reflect the clinical outcome, highlighting the reliability of this model to better profile potential clinical drug candidates. The integrative approach presented herein, which combines longitudinal assessments with endpoint analyses, could be harnessed in drug discovery to generate more reliable, reproducible and robust readouts.

All for one, though not one for all: team players in normal tissue radiobiology

PURPOSE

As part of the special issue on 'Women in Science', this review offers a perspective on past and ongoing work in the field of normal (non-cancer) tissue radiation biology, highlighting the work of many of the leading contributors to this field of research. We discuss some of the hypotheses that have guided investigations, with a focus on some of the critical organs considered dose-limiting with respect to radiation therapy, and speculate on where the field needs to go in the future.

CONCLUSIONS

The scope of work that makes up normal tissue radiation biology has and continues to play a pivotal role in the radiation sciences, ensuring the most effective application of radiation in imaging and therapy, as well as contributing to radiation protection efforts. However, despite the proven historical value of preclinical findings, recent decades have seen clinical practice move ahead with altered fractionation scheduling based on empirical observations, with little to no (or even negative) supporting scientific data. Given our current appreciation of the complexity of normal tissue radiation responses and their temporal variability, with tissue- and/or organ-specific mechanisms that include intra-, inter- and extracellular messaging, as well as contributions from systemic compartments, such as the immune system, the need to maintain a positive therapeutic ratio has never been more urgent. Importantly, mitigation and treatment strategies, whether for the clinic, emergency use following accidental or deliberate releases, or reducing occupational risk, will likely require multi-targeted approaches that involve both local and systemic intervention. From our personal perspective as five 'Women in Science', we would like to acknowledge and applaud the role that many female scientists have played in this field. We stand on the shoulders of those who have gone before, some of whom are fellow contributors to this special issue.

Inhaled treprostinil and forced vital capacity in patients with interstitial lung disease and associated pulmonary hypertension: a post-hoc analysis of the INCREASE study

BACKGROUND

INCREASE was a randomised, placebo-controlled, phase 3 trial that evaluated inhaled treprostinil in patients with interstitial lung disease (ILD) and associated pulmonary hypertension. Treprostinil improved exercise capacity from baseline to week 16, assessed with the use of a 6-min walk test, compared with placebo. Improvements in forced vital capacity (FVC) were also reported. The aim of this post-hoc analysis was to further characterise the effects of inhaled treprostinil on FVC in the overall study population and in various subgroups of interest.

METHODS

In this post-hoc analysis, we evaluated FVC changes in the overall study population and in various subgroups defined by cause of disease or baseline clinical parameters. The study population included patients aged 18 years and older who had a diagnosis of ILD based on evidence of diffuse parenchymal lung disease on chest CT done within 6 months before random assignment (not centrally adjudicated). All analyses were done on the intention-to-treat population, defined as individuals who were randomly assigned and received at least one dose of study drug. The INCREASE study is registered with ClinicalTrials.gov, NCT02630316.

FINDINGS

Between Feb 3, 2017, and Aug 30, 2019, 326 patients were enrolled in the INCREASE trial. Inhaled treprostinil was associated with a placebo-corrected least squares mean improvement in FVC of 28·5 mL (SE 30·1; 95% CI -30·8 to 87·7; p=0·35) at week 8 and 44·4 mL (35·4; -25·2 to 114·0; p=0·21) at week 16, with associated percentage of predicted FVC improvements of 1·8% (0·7; 0·4 to 3·2; p=0·014) and 1·8% (0·8; 0·2 to 3·4; p=0·028). Subgroup analysis of patients with idiopathic interstitial pneumonia showed FVC differences of 46·5 mL (SE 39·9; 95% CI -32·5 to 125·5; p=0·25) at week 8 and 108·2 mL (46·9; 15·3 to 201·1; p=0·023) at week 16. Analysis of patients with idiopathic pulmonary fibrosis showed FVC differences of 84·5 mL (52·7; -20·4 to 189·5; p=0·11) at week 8 and 168·5 mL (64·5; 40·1 to 297·0; p=0·011) at week 16. The most frequent adverse events included cough, headache, dyspnoea, dizziness, nausea, fatigue, and diarrhoea.

INTERPRETATION

In patients with ILD and associated pulmonary hypertension, inhaled treprostinil was associated with improvements in FVC versus placebo at 16 weeks. This difference was most evident in patients with idiopathic interstitial pneumonia, particularly idiopathic pulmonary fibrosis. Inhaled treprostinil appears to be a promising therapy for idiopathic pulmonary fibrosis that warrants further investigation in a prospective, randomised, placebo-controlled study.

FUNDING

United Therapeutics Corporation.

Study design of a randomised, placebo-controlled trial of nintedanib in children and adolescents with fibrosing interstitial lung disease

Childhood interstitial lung disease (chILD) comprises >200 rare respiratory disorders, with no currently approved therapies and variable prognosis. Nintedanib reduces the rate of forced vital capacity (FVC) decline in adults with progressive fibrosing interstitial lung diseases (ILDs). We present the design of a multicentre, prospective, double-blind, randomised, placebo-controlled clinical trial of nintedanib in patients with fibrosing chILD (1199-0337 or InPedILD; ClinicalTrials.gov: NCT04093024).

Male or female children and adolescents aged 6–17 years (≥30; including ≥20 adolescents aged 12–17 years) with clinically significant fibrosing ILD will be randomised 2:1 to receive oral nintedanib or placebo on top of standard of care for 24 weeks (double-blind), followed by variable-duration nintedanib (open-label). Nintedanib dosing will be based on body weight-dependent allometric scaling, with single-step dose reductions permitted to manage adverse events. Eligible patients will have evidence of fibrosis on high-resolution computed tomography (within 12 months of their first screening visit), FVC ≥25% predicted, and clinically significant disease (Fan score of ≥3 or evidence of clinical progression over time). Patients with underlying chronic liver disease, significant pulmonary arterial hypertension, cardiovascular disease, or increased bleeding risk are ineligible. The primary endpoints are pharmacokinetics and the proportion of patients with treatment-emergent adverse events at week 24. Secondary endpoints include change in FVC% predicted from baseline, Pediatric Quality of Life Questionnaire, oxygen saturation, and 6-min walk distance at weeks 24 and 52. Additional efficacy and safety endpoints will be collected to explore long-term effects.

We describe the design of #InPedILD, a study of 24 weeks’ nintedanib or placebo on top of standard of care, followed by variable-duration open-label nintedanib in children with interstitial lung disease (ClinicalTrials.gov NCT04093024) #PedILDhttps://bit.ly/3tC1a7P

Three-Dimensional Idiopathic Pulmonary Fibrosis Model Using a Layer-by-Layer Cell Coating Technique

Idiopathic pulmonary fibrosis (IPF) is a severe health problem characterized by progressive fibroblast proliferation and aberrant vascular remodeling. However, the lack of a suitable in vitro model that replicates cell-specific changes in IPF tissue is a crucial issue. Three-dimensional (3D) cell cultures allow the mimicking of cell-specific functions, facilitating development of novel antifibrosis drugs. We have established a layer-by-layer (LbL) cell coating technique that enables the construction of 3D tissue and also vascularized 3D tissue. This study evaluated whether this technique is beneficial for constructing an in vitro IPF-3D model using human lung fibroblasts and microvascular endothelial cells. We fabricated an in vitro IPF-3D model to provide IPF-derived fibroblasts-specific function and aberrant microvascular structure using the LbL cell coating technique. We also found that this in vitro IPF-3D model showed drug responsiveness to two antifibrosis drugs that have recently been approved worldwide. This in vitro IPF-3D model constructed by a LbL cell coating technique would help in the understanding of fibroblast function and the microvascular environment in IPF and could also be used to predict the efficacy of novel antifibrosis drugs. Impact statement We established a novel in vitro model mimicking idiopathic pulmonary fibrosis. Three-dimensional culture was constructed by layer-by-layer cell coating technique. This novel model provides a visualization of fibroblast-specific function. This assay allows for the assessment of pulmonary microvascular environment. Our model may be useful for predicting the efficacy of novel antifibrosis drugs.

Promising drug repurposing approach targeted for cytokine storm implicated in SARS-CoV-2 complications

A global threat has emerged in 2019 due to the rapid spread of Coronavirus disease (COVID-19). As of January 2021, the number of cases worldwide reached 103 million cases and 2.22 million deaths which were confirmed as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This global pandemic galvanized the scientific community to study the causative virus (SARS-CoV2) pathogenesis, transmission, and clinical symptoms. Remarkably, the most common complication associated with this disease is the cytokine storm which is responsible for COVID-19 mortality. Thus, targeting the cytokine storm with new medications is needed to hamper COVID-19 complications where the most prominent strategy for the treatment is drug repurposing. Through this strategy, several steps are skipped especially those required for testing drug safety and thus may help in reducing the dissemination of this pandemic. Accordingly, the aim of this review is to outline the pathogenesis, clinical features, and immune complications of SARS-CoV2 in addition to suggesting several repurposed drugs with their plausible mechanism of action for possible management of severe COVID-19 cases.

Deglycosylated Azithromycin Attenuates Bleomycin-Induced Pulmonary Fibrosis via the TGF-β1 Signaling Pathway

Idiopathic pulmonary fibrosis (IPF) is a progressive, life-threatening lung disease characterized by the proliferation of myofibroblasts and deposition of extracellular matrix that results in irreversible distortion of the lung structure and the formation of focal fibrosis. The molecular mechanism of IPF is not fully understood, and there is no satisfactory treatment. However, most studies suggest that abnormal activation of transforming growth factor-β1 (TGF-β1) can promote fibroblast activation and epithelial to mesenchymal transition (EMT) to induce pulmonary fibrosis. Deglycosylated azithromycin (Deg-AZM) is a compound we previously obtained by removing glycosyls from azithromycin; it was demonstrated to exert little or no antibacterial effects. Here, we discovered a new function of Deg-AZM in pulmonary fibrosis. In vivo experiments showed that Deg-AZM could significantly reduce bleomycin-induced pulmonary fibrosis and restore respiratory function. Further study revealed the anti-inflammatory and antioxidant effects of Deg-AZM in vivo. In vitro experiments showed that Deg-AZM inhibited TGF-β1 signaling, weakened the activation and differentiation of lung fibroblasts, and inhibited TGF-β1-induced EMT in alveolar epithelial cells. In conclusion, our findings show that Deg-AZM exerts antifibrotic effects by inhibiting TGF-β1-induced myofibroblast activation and EMT.

The Caveolin-1 Scaffolding Domain Peptide Reverses Aging-Associated Deleterious Changes in Multiple Organs

Aging is a progressive, multifactorial, degenerative process in which deleterious changes occur in the biochemistry and function of organs. We showed that angiotensin II (AngII)-induced pathologies in the heart and kidney of young (3-month-old) mice are suppressed by the caveolin-1 scaffolding domain (CSD) peptide. Because AngII mediates many aging-associated changes, we explored whether CSD could reverse pre-existing pathologies and improve organ function in aged mice. Using 18-month-old mice (similar to 60-year-old humans), we found that >5-fold increases in leakage of serum proteins and >2-fold increases in fibrosis are associated with aging in the heart, kidney, and brain. Because tyrosine phosphorylation of cell junction proteins leads to the loss of microvascular barrier function, we analyzed the activation of the receptor tyrosine kinase PDGFR and the nonreceptor tyrosine kinases c-Src and Pyk2. We observed 5-fold activation of PDGFR and 2- to 3-fold activation of c-Src and Pyk2 in aged mice. Treatment with CSD for 4 weeks reversed these pathologic changes (microvascular leakage, fibrosis, kinase activation) in all organs almost down to the levels in healthy, young mice. In studies of heart function, CSD reduced the aging-associated increase in cardiomyocyte cross-sectional area and enhanced ventricular compliance in that echocardiographic studies demonstrated improved ejection fraction and fractional shortening and reduced isovolumic relation time. These results suggest that versions of CSD may be developed as treatments for aging-associated diseases in human patients based on the concept that CSD inhibits tyrosine kinases, leading to the inhibition of microvascular leakage and associated fibrosis, thereby improving organ function. SIGNIFICANCE STATEMENT: The caveolin-1 scaffolding domain (CSD) peptide reverses aging-associated fibrosis, microvascular leakage, and organ dysfunction in the heart, kidneys, and brain via a mechanism that involves the suppression of the activity of multiple tyrosine kinases, suggesting that CSD can be developed as a treatment for a wide range of diseases found primarily in the aged.

Current and future treatment for idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fibrosing interstitial lung disease, which is associated with a short survival rate. The decline in forced vital capacity in patients with IPF appears to be almost the same rate regardless of baseline lung function status. This suggests that early treatment would be necessary to prevent further deterioration even lung function is maintained within normal limits. Both pirfenidone and nintedanib significantly slow the decline in lung function, reduce the risk of acute exacerbation, and improve survival rate. However, many individuals with IPF remain untreated. Most IPF patients can tolerate antifibrotic drug therapy, and the dose adjustment has been shown to effectively reduce side effects without modifying efficacy. Although the recent introduction of pirfenidone and nintedanib has led to the slowing of lung function decline, there is no evidence of fibrosis reversal. In the near future, several new drugs are expected to be prescribed to patients with IPF. We are anticipating that some drugs may reverse fibrosis. Fibrosis inhibiting drugs have different pharmacological actions and there are various mechanisms causing fibrosis in the lesion. Therefore, it is imperative to launch efforts to optimize antifibrotic effects through a combination therapy of several drugs. These efforts will hold out hope for patients with IPF.

The Effect of Nintedanib on T-Cell Activation, Subsets and Functions

Background

T cells are important regulators of inflammation and, via release of mediators, can contribute to pulmonary fibrosis. Nintedanib is approved for the treatment of idiopathic pulmonary fibrosis, systemic sclerosis-associated interstitial lung disease (ILD) and chronic fibrosing ILDs with a progressive phenotype. However, how nintedanib targets T cells has not been elucidated.

Materials and Methods

We investigated the immunomodulatory effects of nintedanib on T cells and peripheral blood mononuclear cells isolated from healthy donors. Cells were pre-incubated with different concentrations of nintedanib and then stimulated for 24 hours with anti-CD3 with or without anti-CD28 and with or without different cytokines. Levels of interferon gamma (IFN-γ), interleukin (IL)-2, IL-4, IL-5, IL-10, IL-12p70 and IL-13 were quantitated. Western blotting with primary antibodies against phospho-Lck-Y394, phospho-Lck-Y505, Lck-total and Cofilin examined the phosphorylation level of the Lck protein. In vitro T-cell proliferation, T-cell clustering and different T-cell populations were also assessed.

Results

Nintedanib blocked T-cell activation through inhibiting Lck-Y394 phosphorylation. Pretreatment of T cells with nintedanib reduced cluster formation as a marker of activation and inhibited the release of IFN-γ, IL-2, IL-4, IL-5, IL-10, IL-12p70 and IL-13 at clinically relevant concentrations ranging from 5–77 nmol/L. Nintedanib did not alter T-cell proliferation or numbers of CD4+ and CD8+ T cells, but did increase stimulated Th17-like cells without increasing IL-17A levels.

Conclusion

These immunomodulatory effects may further explain how nintedanib slows the progression of pulmonary fibrosis in various ILDs.

Cardiovascular safety of the tyrosine kinase inhibitor nintedanib

The intracellular tyrosine kinase inhibitor nintedanib has shown great efficacy for the treatment of idiopathic pulmonary fibrosis (IPF) and other interstitial lung diseases. However, the incidence rate of myocardial infarction (MI) among participants in landmark IPF trials was remarkable, peaking at 3/100 patient-years. Although subjects with IPF often have a high cardiovascular (CV) risk profile, the occurrence of MI in nintedanib-treated patients may not be fully explained by clustering of CV risk factors. Nintedanib inhibits the vascular endothelial growth factor, platelet-derived growth factor and fibroblast growth factor pathways, which play important roles in the biology of the atherosclerotic plaque and in the response of the heart to ischaemia. Hence, unwanted CV effects may partly account for nintedanib-related MI. We review the evidence supporting this hypothesis and discuss possible actions for a safe implementation of nintedanib in clinical practice, building on the experience with tyrosine kinase inhibitors acquired in cardio-oncology.

Imaging Biomarkers in Animal Models of Drug-Induced Lung Injury: A Systematic Review

For drug-induced interstitial lung disease (DIILD) translational imaging biomarkers are needed to improve detection and management of lung injury and drug-toxicity. Literature was reviewed on animal models in which in vivo imaging was used to detect and assess lung lesions that resembled pathological changes found in DIILD, such as inflammation and fibrosis. A systematic search was carried out using three databases with key words “Animal models”, “Imaging”, “Lung disease”, and “Drugs”. A total of 5749 articles were found, and, based on inclusion criteria, 284 papers were selected for final data extraction, resulting in 182 out of the 284 papers, based on eligibility. Twelve different animal species occurred and nine various imaging modalities were used, with two-thirds of the studies being longitudinal. The inducing agents and exposure (dose and duration) differed from non-physiological to clinically relevant doses. The majority of studies reported other biomarkers and/or histological confirmation of the imaging results. Summary of radiotracers and examples of imaging biomarkers were summarized, and the types of animal models and the most used imaging modalities and applications are discussed in this review. Pathologies resembling DIILD, such as inflammation and fibrosis, were described in many papers, but only a few explicitly addressed drug-induced toxicity experiments.

Identification and characterization of novel metabolites of nintedanib by ultra-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry with in silico toxicological assessment

RATIONALE

Nintedanib, an oral, triple angiokinase inhibitor, is used alongside docetaxel in the management of locally recurrent non-small-cell lung cancer and idiopathic pulmonary fibrosis. The present study deals with the identification and characterization of in vitro and in vivo stable and reactive (if any) metabolites of nintedanib and sheds light on some novel metabolites of the drug which have not been reported previously.

METHODS

The study involved an oral administration of the drug to male Wistar rats, followed by collection of the biological matrices (urine, plasma and feces) at specific intervals for determination of in vivo metabolites. In addition, in vitro studies were performed on human and rat liver microsomes in the presence of appropriate co-factors. The samples were subjected to protein precipitation and nitrogen evaporation prior to ultra-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry analysis. The toxicities of all the metabolites were assessed in silico, employing ADMET Predictor™.

RESULTS

A total of 18 metabolites of nintedanib were identified in all the matrices, of which nine were found to be novel and unreported previously. The unreported metabolites were elucidated as oxidative, demethylated and glucuronide conjugates of nintedanib. Interestingly, acetonitrile adducts of a few metabolites (low concentration) were also observed. No reactive metabolites were observed in this study.

CONCLUSIONS

Characterization of hitherto unknown in vitro and in vivo metabolites of nintedanib adds to the existing knowledge on the metabolism of the drug. Identification on the basis of the solvated adducts can be a useful approach for characterization of minor metabolites, which remain undetected owing to sensitivity issues.

Idiopathic pulmonary fibrosis: Molecular mechanisms and potential treatment approaches

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive disease with high mortality that commonly occurs in middle-aged and older adults. IPF, characterized by a decline in lung function, often manifests as exertional dyspnea and cough. Symptoms result from a fibrotic process driven by alveolar epithelial cells that leads to increased migration, proliferation, and differentiation of lung fibroblasts. Ultimately, the differentiation of fibroblasts into myofibroblasts, which synthesize excessive amounts of extracellular matrix proteins, destroys the lung architecture. However, the factors that induce the fibrotic process are unclear. Diagnosis can be a difficult process; the gold standard for diagnosis is the multidisciplinary conference. Practical biomarkers are needed to improve diagnostic and prognostic accuracy. High-resolution computed tomography typically shows interstitial pneumonia with basal and peripheral honeycombing. Gas exchange and diffusion capacity are impaired. Treatments are limited, although the anti-fibrotic drugs pirfenidone and nintedanib can slow the progression of the disease. Lung transplantation is often contraindicated because of age and comorbidities, but it improves survival when successful. The incidence and prevalence of IPF has been increasing and there is an urgent need for improved therapies. This review covers the detailed cellular and molecular mechanisms underlying IPF progression as well as current treatments and cutting-edge research into new therapeutic targets.

Pulmonary vessel casting in a rat model of monocrotaline-mediated pulmonary hypertension

Pulmonary hypertension is a chronic vascular disease characterized by pulmonary vasoconstriction and pulmonary arterial remodeling. Pulmonary arterial remodeling is mainly due to small pulmonary arterial wall thickening and lumen occlusion. Previous studies have described intravascular changes in lung sections using histopathology, but few were able to obtain a fine detailed image of the pulmonary vascular system. In this study, we used Microfil compounds to cast the pulmonary arteries in a rat model of monocrotaline-induced pulmonary hypertension. High-quality images that enabled quantification of distal pulmonary arterial branching based on the number of vessel bifurcations/junctions were demonstrated in this model. The branch and junction counts of distal pulmonary arteries significantly decreased in the monocrotaline group compared to the control group, and this effect was inversely proportional to the mean pulmonary artery pressure observed in each group. The patterns of pulmonary vasculature and the methods for pulmonary vessel casting are presented to provide a basis for future studies of pulmonary arterial remodeling due to pulmonary hypertension and other lung diseases that involve the remodeling of vasculature.

Multi-scale models of lung fibrosis

The architectural complexity of the lung is crucial to its ability to function as an organ of gas exchange; the branching tree structure of the airways transforms the tracheal cross-section of only a few square centimeters to a blood-gas barrier with a surface area of tens of square meters and a thickness on the order of a micron or less. Connective tissue comprised largely of collagen and elastic fibers provides structural integrity for this intricate and delicate system. Homeostatic maintenance of this connective tissue, via a balance between catabolic and anabolic enzyme-driven processes, is crucial to life. Accordingly, when homeostasis is disrupted by the excessive production of connective tissue, lung function deteriorates rapidly with grave consequences leading to chronic lung conditions such as pulmonary fibrosis. Understanding how pulmonary fibrosis develops and alters the link between lung structure and function is crucial for diagnosis, prognosis, and therapy. Further information gained could help elaborate how the healing process breaks down leading to chronic disease. Our understanding of fibrotic disease is greatly aided by the intersection of wet lab studies and mathematical and computational modeling. In the present review we will discuss how multi-scale modeling has facilitated our understanding of pulmonary fibrotic disease as well as identified opportunities that remain open and have produced techniques that can be incorporated into this field by borrowing approaches from multi-scale models of fibrosis beyond the lung.

Nintedanib in patients with systemic sclerosis-associated interstitial lung disease: A Japanese population analysis of the SENSCIS trial

OBJECTIVE

We examined the efficacy and safety of nintedanib in Japanese patients with systemic sclerosis-associated interstitial lung disease (SSc-ILD) in the global Safety and Efficacy of Nintedanib in Systemic Sclerosis (SENSCIS) trial.

METHODS

Randomised patients received oral nintedanib 150 mg (N = 34) twice daily or placebo (N = 36) until the last patient reached 52 weeks of treatment (up to 100 weeks). Data were analysed using a subgroup analysis model with Japanese and non-Japanese patients as subgroup variables.

RESULTS

In Japanese patients, the adjusted annual rate of forced vital capacity (FVC) decline over 52 weeks was -86.2 mL/year (nintedanib) and -90.9 mL/year (placebo); treatment difference, 4.67 mL/year (95% confidence interval, -103.28, 112.63). Treatment effect heterogeneity between Japanese and non-Japanese patients was not detected (treatment-by-visit-by-subgroup interaction; p = .49). FVC decline was smaller for nintedanib versus placebo through 100 weeks in Japanese patients. The most commonly reported adverse events with nintedanib were gastrointestinal and liver disorder events; most were mild-to-moderate in severity.

CONCLUSION

In both Japanese and non-Japanese patients with SSc-ILD, nintedanib slowed the progression of ILD, with no heterogeneity detected between the subgroups. The safety profile for nintedanib in Japanese patients was similar to that observed in patients with idiopathic pulmonary fibrosis (ClinicalTrials.gov: NCT02597933).

A Phase I/II Study of Neoadjuvant Cisplatin, Docetaxel, and Nintedanib for Resectable Non-Small Cell Lung Cancer

PURPOSE

Nintedanib enhances the activity of chemotherapy in metastatic non-small cell lung cancer (NSCLC). In this phase I/II study, we assessed safety and efficacy of nintedanib plus neoadjuvant chemotherapy, using major pathologic response (MPR) as primary endpoint.

PATIENTS AND METHODS

Eligible patients had stage IB (≥4 cm)-IIIA resectable NSCLC. A safety run-in phase was followed by an expansion phase with nintedanib 200 mg orally twice a day (28 days), followed by three cycles of cisplatin (75 mg/m²), docetaxel (75 mg/m²) every 21 days plus nintedanib, followed by surgery. With 33 planned patients, the study had 90% power to detect an MPR increase from 15% to 35%.

RESULTS

Twenty-one patients (stages I/II/III, N = 1/8/12) were treated. One of 15 patients treated with nintedanib 200 mg achieved MPR [7%, 95% confidence interval (CI), 0.2%-32%]. Best ORR in 20 evaluable patients was 30% (6/20, 95% CI, 12%-54%). Twelve-month recurrence-free survival and overall survival were 66% (95% CI, 47%-93%) and 91% (95% CI, 79%-100%), respectively. Most frequent treatment-related grade 3-4 toxicities were transaminitis and electrolyte abnormalities. On the basis of an interim analysis the study was discontinued for futility. Higher levels of CD3⁺ and cytotoxic CD3⁺CD8⁺ T cells were found in treated tumors of patients who were alive than in those who died (652.8 vs. 213.4 cells/mm², P = 0.048; 142.3 vs. 35.6 cells/mm², P = 0.018).

CONCLUSIONS

Although tolerated, neoadjuvant nintedanib plus chemotherapy did not increase MPR rate compared with chemotherapy historical controls. Additional studies of the combination in this setting are not recommended. Posttreatment levels of tumor-infiltrating T cells were associated with patient survival. Use of MPR facilitates the rapid evaluation of neoadjuvant therapies.See related commentary by Blakely and McCoach, p. 3499.

Morphomolecular motifs of pulmonary neoangiogenesis in interstitial lung diseases

The pathogenetic role of angiogenesis in interstitial lung diseases (ILDs) is controversial. This study represents the first investigation of the spatial complexity and molecular motifs of microvascular architecture in important subsets of human ILD. The aim of our study was to identify specific variants of neoangiogenesis in three common pulmonary injury patterns in human ILD.We performed comprehensive and compartment-specific analysis of 24 human lung explants with usual intersitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP) and alveolar fibroelastosis (AFE) using histopathology, microvascular corrosion casting, micro-comupted tomography based volumetry and gene expression analysis using Nanostring as well as immunohistochemistry to assess remodelling-associated angiogenesis.Morphometrical assessment of vessel diameters and intervascular distances showed significant differences in neoangiogenesis in characteristically remodelled areas of UIP, NSIP and AFE lungs. Likewise, gene expression analysis revealed distinct and specific angiogenic profiles in UIP, NSIP and AFE lungs.Whereas UIP lungs showed a higher density of upstream vascularity and lower density in perifocal blood vessels, NSIP and AFE lungs revealed densely packed alveolar septal blood vessels. Vascular remodelling in NSIP and AFE is characterised by a prominent intussusceptive neoangiogenesis, in contrast to UIP, in which sprouting of new vessels into the fibrotic areas is characteristic. The molecular analyses of the gene expression provide a foundation for understanding these fundamental differences between AFE and UIP and give insight into the cellular functions involved.

Melatonin Attenuates Cardiac Reperfusion Stress by Improving OPA1-Related Mitochondrial Fusion in a Yap-Hippo Pathway-Dependent Manner

The role of OPA1-related mitochondrial fusion in cardiac reperfusion stress has remained elusive. The aim of our study is to explore whether melatonin alleviates cardiac ischemia-reperfusion (IR) injury by modulating OPA1-related mitochondrial fusion. We found that melatonin reduced infarct area, sustained myocardial function, and suppressed cardiomyocyte death during cardiac reperfusion stress. Biological studies have revealed that IR-inhibited mitochondrial fusion was largely reversed by melatonin through upregulated OPA1 expression. Knocking down OPA1 abrogated the protective effects of melatonin on mitochondrial energy metabolism and mitochondrial apoptosis. In addition, we also found that melatonin modified OPA1 expression through the Yap–Hippo pathway; blockade of the Yap–Hippo pathway induced cardiomyocyte death and mitochondrial damage despite treatment with melatonin. Altogether, our data demonstrated that cardiac IR injury is closely associated with defective OPA1-related mitochondrial fusion. Melatonin supplementation enhances OPA1-related mitochondrial fusion by activating the Yap–Hippo pathway, ultimately reducing cardiac reperfusion stress.

Inhibition of tyrosine kinase receptor signaling attenuates fibrogenesis in an ex vivo model of human renal fibrosis

Poor translation from animal studies to human clinical trials is one of the main hurdles in the development of new drugs. Here, we used precision-cut kidney slices (PCKS) as a translational model to study renal fibrosis and to investigate whether inhibition of tyrosine kinase receptors, with the selective inhibitor nintedanib, can halt fibrosis in murine and human PCKS. We used renal tissue of murine and human origins to obtain PCKS. Control slices and slices treated with nintedanib were studied to assess viability, activation of tyrosine kinase receptors, cell proliferation, collagen type I accumulation, and gene and protein regulation. During culture, PCKS spontaneously develop a fibrotic response that resembles in vivo fibrogenesis. Nintedanib blocked culture-induced phosphorylation of platelet-derived growth factor receptor and vascular endothelial growth factor receptor. Furthermore, nintedanib inhibited cell proliferation and reduced collagen type I accumulation and expression of fibrosis-related genes in healthy murine and human PCKS. Modulation of extracellular matrix homeostasis was achieved already at 0.1 μM, whereas high concentrations (1 and 5 μM) elicited possible nonselective effects. In PCKS from human diseased renal tissue, nintedanib showed limited capacity to reverse established fibrosis. In conclusion, nintedanib attenuated the onset of fibrosis in both murine and human PCKS by inhibiting the phosphorylation of tyrosine kinase receptors; however, the reversal of established fibrosis was not achieved.

Rationale for the evaluation of nintedanib as a treatment for systemic sclerosis-associated interstitial lung disease

Interstitial lung disease is a common manifestation of systemic sclerosis. Systemic sclerosis-associated interstitial lung disease is characterized by progressive pulmonary fibrosis and a reduction in pulmonary function. Effective treatments for systemic sclerosis-associated interstitial lung disease are lacking. In addition to clinical similarities, systemic sclerosis-associated interstitial lung disease shows similarities to idiopathic pulmonary fibrosis in the pathophysiology of the underlying fibrotic processes. Idiopathic pulmonary fibrosis and systemic sclerosis-associated interstitial lung disease culminate in a self-sustaining pathway of pulmonary fibrosis in which fibroblasts are activated, myofibroblasts accumulate, and the excessive extracellular matrix is deposited. Nintedanib is a tyrosine kinase inhibitor that has been approved for the treatment of idiopathic pulmonary fibrosis. In patients with idiopathic pulmonary fibrosis, nintedanib slows disease progression by decreasing the rate of lung function decline. In this review, we summarize the antifibrotic, anti-inflammatory, and attenuated vascular remodeling effects of nintedanib demonstrated in in vitro studies and in animal models of aspects of systemic sclerosis. Nintedanib interferes at multiple critical steps in the pathobiology of systemic sclerosis-associated interstitial lung disease, providing a convincing rationale for its investigation as a potential therapy. Finally, we summarize the design of the randomized placebo-controlled SENSCIS® trial that is evaluating the efficacy and safety of nintedanib in patients with systemic sclerosis-associated interstitial lung disease.