Acute exacerbations of idiopathic pulmonary fibrosis and the role of corticosteroids

Cellular crosstalk in fibrosis: insights into macrophage and fibroblast dynamics

Pathological fibrosis, the excessive deposition of extracellular matrix and tissue stiffening that causes progressive organ dysfunction, underlies diverse chronic diseases. The fibrotic microenvironment is driven by the dynamic microenvironmental interaction between various cell types; macrophages and fibroblasts play central roles in fibrotic disease initiation, maintenance, and progression. Macrophage functional plasticity to microenvironmental stimuli modulates fibroblast functionality by releasing pro-inflammatory cytokines, growth factors, and matrix remodeling enzymes that promote fibroblast proliferation, activation, and differentiation into myofibroblasts. Activated fibroblasts and myofibroblasts serve as the fibrotic effector cells, secreting extracellular matrix components and initiating microenvironmental contracture. Fibroblasts also modulate macrophage function through the release of their own pro-inflammatory cytokines and growth factors, creating bidirectional crosstalk that reinforces the chronic fibrotic cycle. The intricate interplay between macrophages and fibroblasts, including their secretomes and signaling interactions, leads to tissue damage and pathological loss of tissue function. In this review, we examine macrophage-fibroblast reciprocal dynamic interactions in pathological fibrotic conditions. We discuss the specific lineages and functionality of macrophages and fibroblasts implicated in fibrotic progression, with focus on their signal transduction pathways and secretory signalling that enables their pro-fibrotic behaviour. We then finish with a set of recommendations for future experimentation with the goal of developing a set of potential targets for anti-fibrotic therapeutic candidates. Understanding the cellular interactions between macrophages and fibroblasts provides valuable insights into potential therapeutic strategies to mitigate fibrotic disease progression.

Real-World Safety, Tolerability and Effectiveness of Nintedanib in Patients with Idiopathic Pulmonary Fibrosis: Final Report of Post-marketing Surveillance in Japan

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic interstitial pneumonia, which is characterised by progressive worsening of dyspnoea and lung function. Nintedanib treatment is recommended to slow IPF disease progression. The aim of this post-marketing surveillance (PMS) study was to evaluate the safety and effectiveness of nintedanib over 24 months in patients with IPF in a real-world setting in Japan.

METHODS

This prospective, non-interventional, all-case PMS study of nintedanib included Japanese patients with IPF who started nintedanib between 7 October 2015 and 2 May 2023. The primary outcome was to determine the proportion of patients with adverse drug reactions (ADRs), and the secondary outcome was the adjusted absolute change from baseline in forced vital capacity (FVC) at 24 months.

RESULTS

In total, 5717 patients from 1013 institutions were included in the safety analysis (mean ± standard deviation age 71.7 ± 8.1 years, 78.1% male, 70.8% current or former smokers). Most patients (83.9%) had initiated nintedanib at a dose of 150 mg capsules twice daily. At 24 months, 2841 patients (64.8%) had discontinued nintedanib, mainly due to adverse events (44.0%), ADRs (24.1%) or insufficient effectiveness (5.7%). The most common ADRs were diarrhoea (35.5%), hepatic function abnormal (14.4%), decreased appetite (9.9%), liver disorders (7.8%) and nausea (5.8%). The adjusted absolute mean change in FVC from baseline to 24 months was - 212.3 mL (95% confidence interval - 235.3, - 189.3).

CONCLUSION

This is the largest prospective study to investigate patients with IPF who were treated with nintedanib. The safety and effectiveness of nintedanib treatment in this real-world setting of Japanese patients with IPF was similar to that reported in previous studies. Nintedanib effectively slowed the progression of IPF. No new safety concerns were identified, and the need for appropriate management of hepatic disorders and diarrhoea (as per the approved product information) was confirmed.

STUDY REGISTRATION

ClinicalTrials.gov (NCT02607722)/European Union electronic register of Post-Authorisation Studies (EUPAS10891).

lncRNA-mRNA Co-Expression and Regulation Analysis in Lung Fibroblasts from Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease marked by abnormal accumulation of extracellular matrix (ECM) due to dysregulated expression of various RNAs in pulmonary fibroblasts. This study utilized RNA-seq data meta-analysis to explore the regulatory network of hub long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) in IPF fibroblasts. The meta-analysis unveiled 584 differentially expressed mRNAs (DEmRNA) and 75 differentially expressed lncRNAs (DElncRNA) in lung fibroblasts from IPF. Among these, BCL6, EFNB1, EPHB2, FOXO1, FOXO3, GNAI1, IRF4, PIK3R1, and RXRA were identified as hub mRNAs, while AC008708.1, AC091806.1, AL442071.1, FAM111A-DT, and LINC01989 were designated as hub lncRNAs. Functional characterization revealed involvement in TGF-β, PI3K, FOXO, and MAPK signaling pathways. Additionally, this study identified regulatory interactions between sequences of hub mRNAs and lncRNAs. In summary, the findings suggest that AC008708.1, AC091806.1, FAM111A-DT, LINC01989, and AL442071.1 lncRNAs can regulate BCL6, EFNB1, EPHB2, FOXO1, FOXO3, GNAI1, IRF4, PIK3R1, and RXRA mRNAs in fibroblasts bearing IPF and contribute to fibrosis by modulating crucial signaling pathways such as FoxO signaling, chemical carcinogenesis, longevity regulatory pathways, non-small cell lung cancer, and AMPK signaling pathways.

Hospital-level variation in practices and outcomes for patients with severe acute exacerbations of idiopathic pulmonary fibrosis: a retrospective multicentre cohort study

BACKGROUND

In the absence of evidence-based strategies to improve patient outcomes, the management of patients with severe idiopathic pulmonary fibrosis (IPF) exacerbations may vary widely across centres. We assessed between-hospital variation in practices and mortality for patients with severe IPF exacerbations.

METHODS

Using the Premier Healthcare Database from 1 October 2015 to 31 December 2020, we identified patients admitted to intensive care unit (ICU) or intermediate care unit with an IPF exacerbation. We assessed idiosyncratic, between-hospital variation in ICU practices (invasive mechanical ventilation (IMV), non-invasive mechanical ventilation (NIMV), corticosteroid use, and immunosuppressive and/or antioxidant use) and hospital mortality by determining median risk-adjusted hospital rates and intraclass correlation coefficients (ICCs) from hierarchical multivariable regression models. A priori, an ICC>15% was deemed 'high variation'.

RESULTS

We identified 5256 critically ill patients with a severe IPF exacerbation at 385 US hospitals. Hospital median risk-adjusted rates of practices were: IMV (14% (IQR: 8.3%-26%)), NIMV (42% (31%-54%)), corticosteroid use (89% (84%-93%)), and immunosuppressive and/or antioxidant use (3.3% (1.9%-5.8%)). Model ICCs were: IMV (19% (95% CI: 18% to 21%)), NIMV (15% (13% to 16%)), corticosteroid use (9.8% (8.3% to 11%)), and immunosuppressive and/or antioxidant use (8.5% (7.1% to 9.9%)). The median risk-adjusted hospital mortality was 16% (IQR: 11%-24%) with an ICC of 7.5% (95% CI: 6.2% to 8.9%).

INTERPRETATION

We observed high variation in the use of IMV and NIMV, and less variation in corticosteroid and immunosuppressant and/or antioxidant use among patients hospitalised with severe IPF exacerbations. Further research is needed to guide the decisions surrounding initiation of IMV and role of NIMV and to understand the effectiveness of corticosteroids among patients with severe IPF exacerbations.

New insights on Effects of Glucocorticoids in SARS-CoV-2 infection

Objective

Since January 2020, the highly contagious novel coronavirus SARS-CoV-2 has caused a global pandemic. Severe COVID-19 leads to a massive release of proinflammatory mediators, leading to diffuse damage to the lung parenchyma, and the development of acute respiratory distress syndrome. Treatment with the highly potent glucocorticoid (GC) dexamethasone was found to be effective in reducing mortality in severely affected patients.

Methods

To review the effects of glucocorticoids in the context of COVID-19 we performed a literature search in the PubMed database using the terms COVID-19 and glucocorticoid treatment. We identified 1429 article publications related to COVID-19 and glucocorticoid published from 1.1.2020 to the present including 238 review articles and 36 Randomized Controlled Trials. From these studies, we retrieved 13 Randomized Controlled Trials and 86 review articles that were relevant to our review topics. We focused on the recent literature dealing with glucocorticoid metabolism in critically ill patients and investigating the effects of glucocorticoid therapy on the immune system in COVID-19 patients with severe lung injury.

Results

In our review, we have discussed the regulation of the hypothalamic-pituitary-adrenal axis in patients with critical illness, selection of a specific GC for critical illness-related GC insufficiency, and recent studies that investigated hypothalamic-pituitary-adrenal dysfunction in patients with COVID-19. We have also addressed the specific activation of the immune system with chronic endogenous glucocorticoid excess, as seen in patients with Cushing syndrome, and, finally, we have discussed immune activation due to coronavirus infection and the possible mechanisms leading to improved outcomes in patients with COVID-19 treated with GCs.

Conclusion

For clinical endocrinologists prescribing GCs for their patients, a precise understanding of both the molecular- and cellular-level mechanisms of endogenous and exogenous GCs is imperative, including timing of administration, dosage, duration of treatment, and specific formulations of GCs.