Early diagnosis of fibrotic interstitial lung disease: challenges and opportunities

Pulmonary Fibrosis Diagnosis and Disease Progression Detected Via Hair Metabolome Analysis

BACKGROUND

Fibrotic interstitial lung disease is often identified late due to non-specific symptoms, inadequate access to specialist care, and clinical unawareness precluding proper and timely treatment. Biopsy histological analysis is definitive but rarely performed due to its invasiveness. Diagnosis typically relies on high-resolution computed tomography, while disease progression is evaluated via frequent pulmonary function testing. This study tested the hypothesis that pulmonary fibrosis diagnosis and progression could be non-invasively and accurately evaluated from the hair metabolome, with the longer-term goal to minimize patient discomfort.

METHODS

Hair specimens collected from pulmonary fibrosis patients (n = 56) and healthy subjects (n = 14) were processed for metabolite extraction using 2DLC/MS-MS, and data were analyzed via machine learning. Metabolomic data were used to train machine learning classification models tuned via a rigorous combination of cross validation, feature selection, and testing with a hold-out dataset to evaluate classifications of diseased vs. healthy subjects and stable vs. progressed disease.

RESULTS

Prediction of pulmonary fibrosis vs. healthy achieved AUROCTRAIN = 0.888 (0.794-0.982) and AUROCTEST = 0.908, while prediction of stable vs. progressed disease achieved AUROCTRAIN = 0.833 (0.784 - 0.882) and AUROCTEST = 0. 799. Top metabolites for diagnosis included ornithine, 4-(methylnitrosamino)-1-3-pyridyl-N-oxide-1-butanol, Thr-Phe, desthiobiotin, and proline. Top metabolites for progression included azelaic acid, Thr-Phe, Ala-Tyr, indoleacetyl glutamic acid, and cytidine.

CONCLUSION

This study provides novel evidence that pulmonary fibrosis diagnosis and progression may in principle be evaluated from the hair metabolome. Longer term, this approach may facilitate non-invasive and accurate detection and monitoring of fibrotic lung diseases.

Diagnostic Value of Krebs von den Lungen (KL-6) for Interstitial Lung Disease: A European Prospective Cohort

INTRODUCTION

Krebs von den Lungen 6 (KL-6) is a mucin-1 glycoprotein produced by type II pneumocytes. High levels of KL-6 in blood may be found in patients with lung fibrosis. In Asia this biomarker is used for diagnosis and prognosis in interstitial lung diseases (ILD). There is a lack of information regarding KL-6 cut-off point for diagnosis and prognosis in European population. The aim of this study was to establish the cut-off point for serum KL-6 associated with the presence of ILD in the Spanish population.

METHODS

Prospective study including subjects who underwent chest HRCT, PFTs and autoimmune blood analysis. Two groups were created: non-ILD subjects and ILD patients. Serum KL-6 concentrations were measured using a Lumipulse KL-6 reagent assay and the optimal cut-off value was evaluated by a ROC analysis. Data on demographics and smoking history was also collected.

RESULTS

One hundred seventy-nine patients were included, 102 with ILD. Median serum KL-6 values overall were 762U/mL, 1080 (±787)U/mL for the ILD group vs 340 (±152)U/mL for the non-ILD group (p<0.0001). The main radiological pattern was NSIP (43%). ROC analysis showed greater specificity (86%) and sensitivity (82%) for KL-6 465U/mL for detecting ILD patients. The multivariate logistic regression model pointed to the male sex, higher KL-6 values, lower FVC and low DLCO values as independent factors associated with ILD.

CONCLUSION

Serum KL-6 values greater than 465U/mL have excellent sensitivity and specificity for detecting ILD in our Spanish cohort. Multicentre studies are needed to validate our results.

Improving Accessibility to Patients with Interstitial Lung Disease (ILD): Barriers to Early Diagnosis and Timely Treatment in Latin America

Delayed initiation of effective antifibrotic therapy in patients with interstitial lung diseases (ILD) may influence the progression and outcome of the disease. This study analyzes the differences in the journey of patients with ILD in the Brazilian and Mexican health systems. An evaluative study was conducted in reference centers for interstitial lung diseases in Brazil and Mexico with a panel of four specialists. The patient's journey in both countries begins when the patient seeks medical care after observing a chronic respiratory symptom. In both countries, due to diagnostic complexity, these patients arrive at ILD referral centers at an advanced stage of the disease. Once diagnosis is established, the treatment onset differs between Mexico and Brazil. In Brazil, access to antifibrotic drugs through the public health system has been a significant challenge, and their cost makes them unaffordable for most people. This situation forces medical specialists to provide only supportive care to patients until these drugs can be accessed. In Mexico, antifibrotics have been available in health sectors since 2018. Brazil and Mexico have several similarities regarding the initial journey of the patient due to diagnosis difficulties. Still, the outcome tends to be different due to a difference in access to treatment with antifibrotics. For this reason, advancing health policies that ensure proper treatment for patients with ILD is crucial for the sustainability and reliability of the health system.

[64Cu]Cu-PEG-FUD peptide for noninvasive and sensitive detection of murine pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease resulting in irreversible scarring within the lungs. However, the lack of biomarkers that enable real-time assessment of disease activity remains a challenge in providing efficient clinical decision-making and optimal patient care in IPF. Fibronectin (FN) is highly expressed in fibroblastic foci of the IPF lung where active extracellular matrix (ECM) deposition occurs. Functional upstream domain (FUD) tightly binds the N-terminal 70-kilodalton domain of FN that is crucial for FN assembly. In this study, we first demonstrate the capacity of PEGylated FUD (PEG-FUD) to target FN deposition in human IPF tissue ex vivo. We subsequently radiolabeled PEG-FUD with 64Cu and monitored its spatiotemporal biodistribution via μPET/CT imaging in mice using the bleomycin-induced model of pulmonary injury and fibrosis. We demonstrated [64Cu]Cu-PEG-FUD uptake 3 and 11 days following bleomycin treatment, suggesting that radiolabeled PEG-FUD holds promise as an imaging probe in aiding the assessment of fibrotic lung disease activity.

Prevalence and prognostic meaning of interstitial lung abnormalities in remote CT scans of patients with interstitial lung disease treated with antifibrotic therapy

OBJECTIVES

To describe the prevalence and characteristics of interstitial lung abnormalities (ILA) in CT scans performed prior to the initiation of antifibrotics in a series of patients with interstitial lung disease (ILD), and to identify characteristics apparent on early CT scans that could help to predict outcomes.

METHODS

We conducted a retrospective observational study. The original cohort consisted of 101 patients diagnosed with ILD and treated with antifibrotics in a tertiary hospital. Patients were included if they had a thoracic CT scan performed at least one year before initiation of therapy. They were classified radiologically in three groups: without ILA, with radiological ILA and extensive abnormalities. ILA were classified as subpleural fibrotic, subpleural non-fibrotic and non-subpleural. The initial scan and the latest CT scan performed before treatment were read for assessing progression. The relationship between CT findings of fibrosis and the radiological progression rate and mortality were analyzed.

RESULTS

We included 50 patients. Only 1 (2%) had a normal CT scan, 25 (50%) had extensive alterations and 24 (48%) had radiological criteria for ILA, a median of 98.2 months before initiation of antifibrotics, of them 18 (75%) had a subpleural fibrotic pattern. Significant bronchiectasis and obvious honeycombing in the lower zones were associated with shorter survival (p = 0.04). Obvious honeycombing in the lower zones was also significantly (p < 0.05) associated with a faster progression rate.

CONCLUSIONS

Fibrotic ILAs are frequent in remote scans of patients with clinically relevant ILD, long before they require antifibrotics. Findings of traction bronchiectasis and honeycombing in the earliest scans, even in asymptomatic patients, are related to mortality and progression later on.

How We Do It: Interdisciplinary Diagnosis and Management of Patients With Interstitial Lung Disease and Connective Tissue Disease

A diagnosis of interstitial lung diseases (ILD) can be challenging, and the identification of an associated connective tissue disease (CTD) is crucial to estimate prognosis and to establish the optimal treatment approach. Diagnostic delay, limited expertise, and fragmented care are barriers that impede the delivery of comprehensive health care for patients with rare, complex, and multiorgan diseases such as CTD and ILD. In this article, we present our perspective on the interdisciplinary diagnosis and interprofessional treatment of patients with ILD and suspected CTD or CTD at risk of ILD. We outline the structure of our service, delineating the roles and responsibilities of the team members. Additionally, we provide an overview of our patient population, including diagnostic approaches and specific treatments, and illustrate a patient case. Furthermore, we focus on specific benefits and challenges of joint interdisciplinary and interprofessional patient consultations. The importance of rheumatology and pulmonology assessments in specific patient populations is emphasized. Finally, we explore future directions and discuss potential strategies to improve care delivery for patients with CTD-associated ILD.

Progressive pulmonary fibrosis in patients with connective tissue disease-associated interstitial lung disease: An explorative study

Objectives

The aim of this study was to identify differences and similarities between connective tissue disease (CTD) patients with and without progressive pulmonary fibrosis (PPF) by applying the new guidelines.

Patients and methods

Patient characteristics and disease courses from medical records of 50 CTD-associated Interstitial lung disease (ILD) patients (33 females, 17 males; mean age: 60.1±12.9 years) were longitudinally studied between January 2018 and May 2022. Respiratory involvement in CTD patients was described, and differences in CTD patients who developed PPF compared to those who did not were identified by the 2022 ATS (American Thoracic Society)/ERS (European Respiratory Society)/JRS (Japanese Respiratory Society)/ALAT (Asociación Latinoamericana de Thórax) Guidelines on Idiopathic Pulmonary Fibrosis and Progressive Pulmonary Fibrosis in Adults.

Results

In the majority (74%) of patients, CTD was diagnosed before ILD onset. Nonspecific interstitial pneumonia was the most common high resolution computer tomography pattern, followed by the usual interstitial pneumonia pattern. On pulmonary function test, 38% had a restrictive pattern at baseline. Patients without PPF tended to have worse lung function at baseline and increased macrophage count in bronchoalveolar lavage than patients with PPF.

Conclusion

In patients without PPF, disease progression may be missed, resulting in inadequate management. Interdisciplinary management of patients with CTD with the participation of pulmonologists and precise lung function diagnostics is recommended.

Lung toxicity induced by anti-HER2 antibody - drug conjugates for breast cancer

Human epidermal growth factor receptor 2 (HER2) serves as both a prognostic indicator and a therapeutic target for breast cancer. Therefore, anti-HER2 therapy plays a crucial role in the treatment of HER2-positive cancer. Antibody-drug conjugates (ADCs) are composed of a monoclonal antibody, a chemical linker and a payload, wherein their aim is to reduce the toxicity associated with chemotherapy drugs by utilizing specific antibodies. Among the anti-HER2 ADCs currently approved for clinical use, trastuzumab emtansine(T-DM1) and trastuzumab deruxtecan (T-Dxd) have demonstrated remarkable efficacy in treating HER2-positive breast cancer. However, it is essential to emphasize the occurrence of lung toxicity during the treatment process, which can be life-threatening. In this review, we provide an overview of the new epidemiological features associated with interstitial lung disease (ILD) related to anti-HER2 ADCs in breast cancer. We also summarize the potential pathogenesis and explore the diagnosis and treatment strategies within this field.

Drug-induced interstitial lung disease: a real-world pharmacovigilance study of the FDA Adverse Event Reporting System from 2004 to 2021

Background

Drug-induced interstitial lung disease (DILD) is an increasingly common cause of morbidity and mortality. However, due to the lack of specificity, DILD detection remains an unsolved public health challenge.

Objectives

For the first time, we aimed to examine DILD reports submitted to the Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) to identify demographic characteristics and top drugs associated with DILD at a group level (including age, sex, drug class, and country stratification) and individual drug level.

Design

A retrospective analysis of the FAERS database was examined by disproportionality analysis.

Methods

We reviewed the FAERS database from 2004 to 2021, using search terms 'interstitial lung disease' and sorting cases by generic drug name. The reporting odds ratio, proportional reporting ratio, and Bayesian confidence propagation neural network were calculated as the measure of strength of association.

Results

There were 32,821 DILD reports in the FAERS. After excluding reports without age, sex, or country data according to the specific measurement, the median age of patients was 68 (interquartile range: 59), 54.77% were male, and 46.00% of reports came from Japan. The top drug classes related to DILD in the FAERS were antineoplastic, followed by cardiovascular and antirheumatic agents, in varying order in different sexes. Fam-trastuzumab deruxtecan-nxki, ramucirumab, and eribulin were the top three drugs with the highest strength of association. We also found some drugs without DILD in the labels, such as amiodarone, temsirolimus, and ursodiol. There are significant differences in DILD reports in various countries. For example, the United States and France reported more cardiovascular agents, whereas Canada reported more antirheumatic agents.

Conclusion

We found the top drugs and drug classes that were associated with DILD in the FAERS, which provides a real-world window for different ages, sexes, and countries to formulate precise pharmacovigilance policies.

Detection of fibrosing interstitial lung disease-suspected chest radiographs using a deep learning-based computer-aided detection system: a retrospective, observational study

OBJECTIVES

To investigate the effectiveness of BMAX, a deep learning-based computer-aided detection system for detecting fibrosing interstitial lung disease (ILD) on chest radiographs among non-expert and expert physicians in the real-world clinical setting.

DESIGN

Retrospective, observational study.

SETTING

This study used chest radiograph images consecutively taken in three medical facilities with various degrees of referral. Three expert ILD physicians interpreted each image and determined whether it was a fibrosing ILD-suspected image (fibrosing ILD positive) or not (fibrosing ILD negative). Interpreters, including non-experts and experts, classified each of 120 images extracted from the pooled data for the reading test into positive or negative for fibrosing ILD without and with the assistance of BMAX.

PARTICIPANTS

Chest radiographs of patients aged 20 years or older with two or more visits that were taken during consecutive periods were accumulated. 1251 chest radiograph images were collected, from which 120 images (24 positive and 96 negative images) were randomly extracted for the reading test. The interpreters for the reading test were 20 non-expert physicians and 5 expert physicians (3 pulmonologists and 2 radiologists).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the comparison of area under the receiver-operating characteristic curve (ROC-AUC) for identifying fibrosing ILD-positive images by non-experts without versus with BMAX. The secondary outcome was the comparison of sensitivity, specificity and accuracy by non-experts and experts without versus with BMAX.

RESULTS

The mean ROC-AUC of non-expert interpreters was 0.795 (95% CI; 0.765 to 0.825) without BMAX and 0.825 (95% CI; 0.799 to 0.850) with BMAX (p=0.005). After using BMAX, sensitivity was improved from 0.744 (95% CI; 0.697 to 0.791) to 0.802 (95% CI; 0.754 to 0.850) among non-experts (p=0.003), but not among experts (p=0.285). Specificity and accuracy were not changed after using BMAX among either non-expert or expert interpreters.

CONCLUSION

BMAX was useful for detecting fibrosing ILD-suspected chest radiographs for non-expert physicians.

TRIAL REGISTRATION NUMBER

jRCT1032220090.

Factors associated with rapid progression in fibrotic interstitial lung disease

Background

Early identification of fibrotic interstitial lung disease (F-ILD) patients with high risk of progression will help initiate early therapeutic intervention and potential improvement of outcomes. This study was designed to assess the predictors of progression in patients with F-ILD.

Methods

Patients with F-ILD in Shanghai Pulmonary Hospital between January 1, 2019 and July 31, 2021 were retrospectively analyzed. The patients enrolled were divided into progressive group and non-progressive group according to the specified criteria. Baseline characteristics were collected and a multivariate regression was conducted to identify independent predictors of progression.

Results

Of the 177 F-ILD cases, 87 were enrolled in the progressive group and 90 were in the non-progressive group. The cohort included 11 types of F-ILD, primarily were connective tissue disease-associated interstitial lung disease (CTD-ILD) (43, 24.3 %), idiopathic pulmonary fibrosis (IPF) (39, 22.0 %), interstitial pneumonia with autoimmune features (IPAF) (32, 18.1 %), and unclassifiable (23, 13.0 %). The highest proportion of progression was seen in nonspecific interstitial pneumonia (NSIP) subgroup (66.7 %), followed by IPF (59.0 %) and HP (57.1 %). After adjusting for gender and age, a course of disease longer than 9.5 months (OR: 2.633; 95 % CI: 1.190-5.826, P = 0.017), lymphocyte in peripheral blood more than 2.24 (109/L) (OR: 2.670; 95 % CI: 1.095-6.510, P = 0.031), and emphysema in high-resolution computed tomography (HRCT) (OR: 2.387; 95 % CI: 1.017-5.640, P = 0.046) were independent predictors of progression in F-ILD patients.

Conclusions

This study suggested that in patients with F-ILD, long course of disease, elevated blood lymphocyte and emphysema on HRCT were independent predictors of progression, which may suggest utility in early therapeutic intervention.

Defining the pathway to timely diagnosis and treatment of interstitial lung disease: a US Delphi survey

INTRODUCTION

Timely diagnosis of interstitial lung disease (ILD) is limited by obstacles in the current patient pathway. Misdiagnosis and delays are common and may lead to a significant burden of diagnostic procedures and worse outcomes. This Delphi survey aimed to identify consensus on the key steps that facilitate the patient journey to an accurate ILD diagnosis and appropriate management in the US.

METHODS

A modified Delphi analysis was conducted, comprising three online surveys based on a comprehensive literature search. The surveys spanned five domains (guidelines, community screening, diagnosis, management and specialist referral) and were completed by a panel of US physicians, including primary care physicians and pulmonologists practising in community or academic settings. A priori definitions of consensus agreement were median scores of 2-3 (agree strongly/agree), with an IQR of 0-1 for questions on a 7-point Likert scale from -3 to 3, or ≥80% agreement for binary questions.

RESULTS

Forty-nine panellists completed the surveys and 62 statements reached consensus agreement. There was consensus agreement on what should be included in the primary care evaluation of patients with suspected ILD and the next steps following workup. Regarding diagnosis in community pulmonology care, consensus agreement was reached on the requisition and reporting of high-resolution CT scans and the appropriate circumstances for holding multidisciplinary discussions. Additionally, there was consensus agreement on which symptoms and comorbidities should be monitored, the frequency of consultations and the assessment of disease progression. Regarding specialist referral, consensus agreement was reached on which patients should receive priority access to ILD centres and the contents of the referral package.

CONCLUSIONS

These findings clarify the most common issues that should merit further evaluation for ILD and help define the steps for timely, accurate diagnosis and appropriate collaborative specialty management of patients with ILD.

Speaking of the "Devil": Diagnostic Errors in Interstitial Lung Diseases

Interstitial lung diseases are respiratory diseases, which affect the normal lung parenchyma and can lead to significant pulmonary fibrosis, chronic respiratory failure, pulmonary hypertension, and ultimately death. Reuniting more than 200 entities, interstitial lung diseases pose a significant challenge to the clinician, as they represent rare diseases with vague and insidious respiratory symptoms. As such, there are many diagnostic errors that can appear along the journey of the patient with ILD, which leads to significant delays with implications for the prognosis and the quality of life of the patient.

Differentiating interstitial lung diseases from other respiratory diseases using electronic nose technology

INTRODUCTION

Interstitial lung disease (ILD) may be difficult to distinguish from other respiratory diseases due to overlapping clinical presentation. Recognition of ILD is often late, causing delay which has been associated with worse clinical outcome. Electronic nose (eNose) sensor technology profiles volatile organic compounds in exhaled breath and has potential to detect ILD non-invasively. We assessed the accuracy of differentiating breath profiles of patients with ILD from patients with asthma, chronic obstructive pulmonary disease (COPD), and lung cancer using eNose technology.

METHODS

Patients with ILD, asthma, COPD, and lung cancer, regardless of stage or treatment, were included in a cross-sectional study in two hospitals. Exhaled breath was analysed using an eNose (SpiroNose) and clinical data were collected. Datasets were split in training and test sets for independent validation of the model. Data were analyzed with partial least squares discriminant and receiver operating characteristic analyses.

RESULTS

161 patients with ILD and 161 patients with asthma (n = 65), COPD (n = 50) or lung cancer (n = 46) were included. Breath profiles of patients with ILD differed from all other diseases with an area under the curve (AUC) of 0.99 (95% CI 0.97-1.00) in the test set. Moreover, breath profiles of patients with ILD could be accurately distinguished from the individual diseases with an AUC of 1.00 (95% CI 1.00-1.00) for asthma, AUC of 0.96 (95% CI 0.90-1.00) for COPD, and AUC of 0.98 (95% CI 0.94-1.00) for lung cancer in test sets. Results were similar after excluding patients who never smoked.

CONCLUSIONS

Exhaled breath of patients with ILD can be distinguished accurately from patients with other respiratory diseases using eNose technology. eNose has high potential as an easily accessible point-of-care medical test for identification of ILD amongst patients with respiratory symptoms, and could possibly facilitate earlier referral and diagnosis of patients suspected of ILD.

Macrophage polarization in tissue fibrosis

Fibrosis can occur in all major organs with relentless progress, ultimately leading to organ failure and potentially death. Unfortunately, current clinical treatments cannot prevent or reverse tissue fibrosis. Thus, new and effective antifibrotic therapeutics are urgently needed. In recent years, a growing body of research shows that macrophages are involved in fibrosis. Macrophages are highly heterogeneous, polarizing into different phenotypes. Some studies have found that regulating macrophage polarization can inhibit the development of inflammation and cancer. However, the exact mechanism of macrophage polarization in different tissue fibrosis has not been fully elucidated. This review will discuss the major signaling pathways relevant to macrophage-driven fibrosis and profibrotic macrophage polarization, the role of macrophage polarization in fibrosis of lung, kidney, liver, skin, and heart, potential therapeutics targets, and investigational drugs currently in development, and hopefully, provide a useful review for the future treatment of fibrosis.

Clinical spectrum of Chinese hospitalized lung cancer patients with concomitant interstitial lung disease: before and after the new era of LC treatment

This study aimed to explore the general characteristics and spectrum of hospitalized Chinese patients suffering from lung cancer with concomitant interstitial lung disease (LC-ILD). Furthermore, we compared their features before and after the period of immunotherapy for lung cancer. A retrospective analysis of the clinical characteristics of hospitalized LC patients with definite pathological diagnoses was performed from 2014 to 2021. ILD was defined after the review of chest CT imaging. There were 13,085 hospitalized LC patients. Among them, 509 patients (3.89%) had 551 cases of ILD. There were variable underlying causes of ILD, including idiopathic interstitial pneumonia (360 patients), LC treatment-associated ILD (134 cases), and connective tissue disease-associated ILD (55 patients). Although most LC-ILD patients were suffering from adenocarcinoma (204/40.1%), SCLC patients were prone to concomitant ILD (10.8% of all SCLC cases), followed by SCC (9.6% of all SCC cases). All but 10 LC-ILD patients received anti-LC treatment; however, only 39 (10.8%) LC-IIP patients received anti-ILD treatment. There were more LC-ILD patients in the 2018-2021 group than in the 2014-2017 group (5.16% vs. 2.03%, p < 0.001). The underlying causes of ILD were significantly different between the 2018-2021 group and the 2014-2017 group (p < 0.001). After adjusting for the number of hospitalized patients having the same LC pathological pattern, SCLC was determined to be the most likely to be concomitant with ILD, followed by SCC. Most LC-ILD patients were scheduled for anti-LC therapy; however, treatments for concomitant IIP were usually ignored. LC treatment-associated ILD should receive more attention than before.

Barriers to and facilitators of the use of oxygen therapy in people living with an interstitial lung disease: a systematic review of qualitative evidence

BACKGROUND

Oxygen therapy is prescribed to treat hypoxaemia in people with interstitial lung disease (ILD); however, uptake and adherence remain an ongoing challenge. This systematic review aimed to identify the barriers to and facilitators of use of oxygen therapy in people with ILD, caregivers and health professionals.

METHODS

A systematic search for qualitative literature was undertaken using five electronic databases (MEDLINE, CINAHL, Embase, PsycINFO, PubMed). Qualitative analysis identified themes that were mapped to the Theoretical Domains Framework and the Consolidated Framework for Implementation Research and classified as barriers, facilitators or both.

RESULTS

A total of 13 studies were eligible for inclusion. Commonly represented domains were associated with the design of the oxygen delivery system, the associated cost, financing, stigmatisation, the physical environment and the individual needs that acted as barriers to and facilitators of the optimisation of oxygen therapy.

CONCLUSION

Effective implementation of oxygen therapy in ILD requires more robust evidence to strengthen international guidelines, sustainable and equitable funding models, and improved oxygen delivery systems that meet the needs of users. Increased information and support for users will be critical to optimise the uptake and outcomes of this important therapy.

CT Patterns of Interstitial Lung Disease in Patients with Plaque Psoriasis: A Retrospective Case Series Study

Background and Objectives: Recently published articles reported an association between psoriasis and interstitial lung diseases (ILDs). The aim of this study is to evaluate the differences in ILD computed tomography (CT) patterns between smoker and never smoker plaque psoriasis (PP) patients under topical treatment without psoriatic arthritis (PA), inflammatory bowel disease (IBD) or connective tissue diseases (CTDs). Matherials and Methods: Two radiologists evaluated chest CT examinations of 65 patients (33 smokers, 32 never smokers) with PP. Results: Usual interstitial pneumonia (UIP) pattern was diagnosed in 36 patients, nonspecific interstitial pneumonia pattern in 19, hypersensitivity pneumonitis in 7 and pleuropulmonary fibroelastosis (PPFE) in 3 patients. UIP pattern showed a statistically significant higher frequency in smoker patients (p = 0.0351). Respiratory symptoms were reported in 80% of patients. Conclusions: ILDs seems to represent a new comorbidity associated with psoriasis. Moreover, a statistically significant association between smokers and UIP pattern in PP patients is found. Respiratory symptoms should be evaluated in PP patients, in collaboration with a radiologist and a pneumologist. However, further studies are required to better understand the epidemiology of ILDs in PP patients.

Holistic management of patients with progressive pulmonary fibrosis

Progressive pulmonary fibrosis (PF) is a complex interstitial lung disease that impacts substantially on patients' daily lives, requiring personalised and integrated care. We summarise the main needs of patients with PF and their caregivers, and suggest a supportive care approach. Individualised care, education, emotional and psychological support, specialised treatments, and better access to information and resources are necessary. Management should start at diagnosis, be tailored to the patient's needs, and consider end-of-life care. Pharmacological and non-pharmacological interventions should be individualised, including oxygen therapy and pulmonary rehabilitation, with digital healthcare utilised as appropriate. Further research is needed to address technical issues related to oxygen delivery and digital healthcare.

Educational aims

To identify the main needs of patients with PF and their caregivers.To describe the components of a comprehensive approach to a supportive care programme for patients with PF.To identify further areas of research to address technical issues related to the management of patients with PF.

High prevalence of interstitial lung abnormalities in middle-aged never-smokers

Background

Interstitial lung abnormalities (ILA) are incidental findings on chest computed tomography (CT). These patterns can present at an early stage of fibrotic lung disease. Our aim was to estimate the prevalence of ILA in the Swedish population, in particular in never-smokers, and find out its association with demographics, comorbidities and symptoms.

Methods

Participants were recruited to the Swedish CArdioPulmonary BioImage Study (SCAPIS), a population-based survey including men and women aged 50-64 years performed at six university hospitals in Sweden. CT scan, spirometry and questionnaires were performed. ILA were defined as cysts, ground-glass opacities, reticular abnormality, bronchiectasis and honeycombing.

Findings

Out of 29 521 participants, 14 487 were never-smokers and 14 380 were men. In the whole population, 2870 (9.7%) had ILA of which 134 (0.5%) were fibrotic. In never-smokers, the prevalence was 7.9% of which 0.3% were fibrotic. In the whole population, age, smoking history, chronic bronchitis, cancer, coronary artery calcium score and high-sensitive C-reactive protein were associated with ILA. Both ILA and fibrotic ILA were associated with restrictive spirometric pattern and impaired diffusing capacity of the lung for carbon monoxide. However, individuals with ILA did not report more symptoms compared with individuals without ILA.

Interpretation

ILA are common in a middle-aged Swedish population including never-smokers. ILA may be at risk of being underdiagnosed among never-smokers since they are not a target for screening.

An observational cohort study of interstitial lung abnormalities (ILAs) in a large Japanese health screening population (Kumamoto ILA study in Japan: KILA-J)

BACKGROUND

Interstitial lung abnormalities (ILAs) are subtle or mild parenchymal abnormalities observed in more than 5% of the lungs on computed tomography (CT) scans in patients in whom interstitial lung disease was not previously clinically suspected and is considered. ILA is considered to be partly undeveloped stages of idiopathic pulmonary fibrosis (IPF) or progressive pulmonary fibrosis (PPF). This study aims to clarify the frequency of subsequent IPF or PPF diagnosis, the natural course from the preclinical status of the diseases, and the course after commencing treatment.

METHODS

This is an ongoing, prospective, multicentre observational cohort study of patients with ILA referred from general health screening facilities with more than 70,000 annual attendances. Up to 500 participants will be enrolled annually over 3 years, with 5-year assessments every six months. Treatment intervention including anti-fibrotic agents will be introduced in disease progression cases. The primary outcome is the frequency of subsequent IPF or PPF diagnoses. Additionally, secondary and further endpoints are associated with the efficacy of early therapeutic interventions in cases involving disease progression, including quantitative assessment by artificial intelligence.

DISCUSSION

This is the first prospective, multicentre, observational study to clarify (i) the aetiological data of patients with ILA from the largest general health check-up population, (ii) the natural course of IPF or PPF from the asymptomatic stage, and (iii) the effects and outcomes of early therapeutic intervention including anti-fibrotic agents for progressive cases of ILA. The results of this study could significantly impact the clinical practice and treatment strategy for progressive fibrosing interstitial lung diseases.

TRIAL REGISTRATION NUMBER

UMIN000045149.

Biodistribution, Dosimetry, and Pharmacokinetics of 68Ga-CBP8: A Type I Collagen-Targeted PET Probe

The 68Ga-Collagen Binding Probe #8, 68Ga-CBP8, is a peptide-based, type I collagen-targeted probe developed for imaging of tissue fibrosis. The aim of this study was to determine the biodistribution, dosimetry, and pharmacokinetics of 68Ga-CBP8 in healthy human subjects. Methods: Nine healthy volunteers (5 male and 4 female) underwent whole-body 68Ga-CBP8 PET/MRI using a Biograph mMR scanner. The subjects were imaged continuously for up to 2 h after injection of 68Ga-CBP8. A subset of subjects underwent an additional imaging session 2-3 h after probe injection. OLINDA/EXM software was used to calculate absorbed organ and effective dose estimates based on up to 17 regions of interest (16 for men) defined on T2-weighted MR images and copied to the PET images, assuming a uniform distribution of probe concentration in each region. Serial blood sampling up to 90 min after probe injection was performed to assess blood clearance and metabolic stability. Results: The mean injected activity (±SD) of 68Ga-CBP8 was 220 ± 100 MBq (range, 113-434 MBq). No adverse effects related to probe administration were detected. 68Ga-CBP8 demonstrated an extracellular distribution with predominantly rapid renal clearance. Doses on the urinary bladder were 0.15 versus 0.19 mGy/MBq for men versus women. The highest absorbed doses for the rest of the organs were measured in the kidneys (0.078 vs. 0.088 mGy/MBq) and the liver (0.032 vs. 0.041 mGy/MBq). The mean effective dose was 0.018 ± 0.0026 mSv/MBq using a 1-h voiding model. The 68Ga-CBP8 signal in the blood demonstrated biexponential pharmacokinetics with an initial distribution half-life of 4.9 min (95% CI, 2.4-9.4 min) and a 72-min elimination half-life (95% CI, 47-130 min). The only metabolite observed had a long blood plasma half-life, suggesting protein-bound 68Ga. Conclusion: 68Ga-CBP8 displays favorable in-human characteristics and dosimetry similar to that of other gallium-based probes. 68Ga-CBP8 could therefore be used for noninvasive collagen imaging across a range of human fibrotic diseases.

Skin disorders and interstitial lung disease: Part I-Screening, diagnosis, and therapeutic principles

Numerous inflammatory, neoplastic, and genetic skin disorders are associated with interstitial lung disease (ILD), the fibrosing inflammation of lung parenchyma that has significant morbidity and mortality. Therefore, the dermatologist plays a major role in the early detection and appropriate referral of patients at risk for ILD. Part 1 of this 2-part CME outlines the pathophysiology of ILD and focuses on clinical screening and therapeutic principles applicable to dermatological patients who are at risk for ILD. Patients with clinical symptoms of ILD should be screened with pulmonary function tests and high-resolution chest computed tomography. Screening for pulmonary hypertension should be considered in high-risk patients. Early identification and elimination of pulmonary risk factors, including smoking and gastroesophageal reflux disease, are essential in improving respiratory outcomes. First-line treatment interventions for ILD in a dermatological setting include mycophenolate mofetil, but the choice of therapeutic agents depends on the nature of the primary disease, the severity of ILD, and comorbidities and should be the result of a multidisciplinary assessment. Better awareness of ILD among medical dermatologists and close interdisciplinary collaborations are likely to prevent treatment delays improving long-term outcomes.

The flare of care for rare: per aspera ad astra for rare lung diseases!

Rare lung diseases have been noticed for centuries: studies on a mummy of an Egyptian male from the 12th dynasty (1991–1783 BC) showed the presence of an interstitial lung disease called sand pneumoconiosis [1]. Rare disorders have a great impact on patients and their families, yet they are frequently misdiagnosed and undertreated [2]. This is caused, in part, by general as well as healthcare professionals’ lack of knowledge of these disorders. Additionally, because rare disorders are so uncommon, there is frequently a shortage of funding for studies into, and management of, these conditions. The understanding and treatment of rare diseases did not make substantial strides until the end of the 20th century. In 1997, the European Organization for Rare Diseases (EURORDIS) was established to advocate on behalf of patients with rare diseases and their families at the European level [3]. With the adoption of the Orphan Medicinal Products Regulation (following the United States’ Orphan Drug Act), a system of incentives for the development of orphan medications was established in the European Union (EU) in 2000.

For rare lung diseases cross border collaborations and joining forces, such as between ERN-LUNG and ERS as well as patient organisations, are crucial to improve diagnosis and management of these diseases.https://bit.ly/3HpqGX1

Monitoring small airway dysfunction in connective tissue disease-related interstitial lung disease: a retrospective and prospective study

BACKGROUND

Small airway dysfunction (SAD), a hallmark of early lung function abnormality, is a major component of several chronic respiratory disorders. The role of SAD in patients with connective tissue disease-related interstitial lung disease (CTD-ILD) has not been explored.

METHODS

We conducted a two-parts (retrospective and prospective) study to collect pulmonary function tests from CTD-ILD patients. SAD was defined as at least two of the three measures (MMEF, FEF 50%, and FEF 75%) must be 65% of predicted values. Spearman correlation coefficient was used to evaluate association between SAD and other pulmonary function parameters. Mixed effects regression modeling analysis was used to assess response to treatment.

RESULTS

CTD-ILD patients with SAD and without SAD were compared in this study. In the retrospective study, pulmonary function tests (PFTs) from 491 CTD-ILD patients were evaluated, SAD were identified in 233 (47.5%). CTD-ILD patients with SAD were less smokers (17.6% vs. 27.9%, p = 0.007) and more females (74.3% vs. 64.0%, p = 0.015) than those without SAD. CTD-ILD patients with SAD had lower vital capacity (% predicted FVC, 70.4 ± 18.3 vs. 80.0 ± 20.9, p < 0.001) and lower diffusion capacity (% predicted DLCO, 58.8 ± 19.7 vs. 63.8 ± 22.1, p = 0.011) than those without SAD. Among 87 CTD-ILD patients prospectively enrolled, significant improvement in % predicted FVC was observed at 12-months follow-up (6.37 ± 1.53, p < 0.001 in patients with SAD; 5.13 ± 1.53, p = 0.002 in patients without SAD), but not in diffusion capacity and SAD parameters.

CONCLUSION

In our cohort, about half of CTD-ILD patients have SAD, which is less frequent in smokers and more common in female patients. CTD-ILD patients with SAD have worse pulmonary function compared to those without SAD. Improvement of FVC but no improvement of SAD was observed in CTD-ILD patients after treatment.

Unmet needs and perspectives in rheumatoid arthritis-associated interstitial lung disease: A critical review

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by synovitis as the most common clinical manifestation, and interstitial lung disease (RA-ILD) represents one of the most common and potentially severe extra-articular features. Our current understanding of the mechanisms and predictors of RA-ILD is limited despite the demonstration that an early identification of progressive fibrosing forms is crucial to provide timely treatment with antifibrotic therapies. While high resolution computed tomography is the gold standard technique for the diagnosis and follow-up of RA-ILD, it has been hypothesized that serum biomarkers (including novel and rare autoantibodies), new imaging techniques such as ultrasound of the lung, or the application of innovative radiologic algorithms may help towards predicting and detecting early forms of diseases. Further, while new treatments are becoming available for idiopathic and connective tissue disease-associated forms of lung fibrosis, the treatment of RA-ILD remains anecdotal and largely unexplored. We are convinced that a better understanding of the mechanisms connecting RA with ILD in a subgroup of patients as well as the creation of adequate diagnostic pathways will be mandatory steps for a more effective management of this clinically challenging entity.

Perspectives of PDE inhibitor on treating idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive interstitial lung disease (ILD) without an identifiable cause. If not treated after diagnosis, the average life expectancy is 3-5 years. Currently approved drugs for the treatment of IPF are Pirfenidone and Nintedanib, as antifibrotic drugs, which can reduce the decline rate of forced vital capacity (FVC) and reduce the risk of acute exacerbation of IPF. However these drugs can not relieve the symptoms associated with IPF, nor improve the overall survival rate of IPF patients. We need to develop new, safe and effective drugs to treat pulmonary fibrosis. Previous studies have shown that cyclic nucleotides participate in the pathway and play an essential role in the process of pulmonary fibrosis. Phosphodiesterase (PDEs) is involved in cyclic nucleotide metabolism, so PDE inhibitors are candidates for pulmonary fibrosis. This paper reviews the research progress of PDE inhibitors related to pulmonary fibrosis, so as to provide ideas for the development of anti-pulmonary fibrosis drugs.

Diffuse lung involvement in rheumatoid arthritis: a respiratory physician's perspective

ABSTRACT

The lungs are one of the most common extra-articular organs involved in rheumatoid arthritis (RA), which is reported to occur in up to 60% to 80% of RA patients. Respiratory complications are the second leading cause of death due to RA. Although there is a wide spectrum of RA-associated respiratory diseases, interstitial lung disease is the most common manifestation and it impacts the prognosis of RA. There has been progress in understanding the management and progression of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) and RA-associated respiratory diseases recently, for example, opportunistic pulmonary infectious diseases and toxicity from RA therapies. From a chest physicians' perspective, we will update the diagnosis and treatment of RA-associated ILD, methotrexate-associated lung disease, and the complication of Pneumocystis jiroveci pneumonia in RA in this review.

Optimizing Screening for Early Disease Detection in Familial Pulmonary Fibrosis (FLORIS): A Prospective Cohort Study Design

Background: Familial pulmonary fibrosis (FPF) can be defined as pulmonary fibrosis in two or more first-degree family members. The first-degree family members of FPF patients are at high risk of developing FPF and are eligible for screening. Reproducible studies investigating risk factors for disease are much needed. Methods: Description of the screening study protocol for a single-center, prospective cohort study; the study will include 200 asymptomatic, first-degree family members of patients with FPF who will undergo three study visits in two years. The primary objective is determining the diagnostic value of parameters for detection of early FPF; the secondary objectives are determining the optimal timing of the screening interval and gaining insight into the natural history of early FPF. The presence of interstitial lung disease (ILD) changes on high-resolution computed tomography of the chest is indicative of preclinical ILD; the changes are determined at baseline. The comparison between the group with and without ILD changes is made for clinical parameters (pulmonary function, presence of digital clubbing, presence of Velcro-like crackles, blood count, liver- and kidney-function testing, patient-reported cough and dyspnea score) and exploratory parameters. Discussion: This study will be the first large-size, prospective, longitudinal cohort study for yearly screening of asymptomatic family members of FPF patients investigating the diagnostic value of parameters, including lung function, to detect early FPF. More effective screening strategies could advance early disease detection.

Novel diagnostic techniques in interstitial lung disease

Research into novel diagnostic techniques and targeted therapeutics in interstitial lung disease (ILD) is moving the field toward increased precision and improved patient outcomes. An array of molecular techniques, machine learning approaches and other innovative methods including electronic nose technology and endobronchial optical coherence tomography are promising tools with potential to increase diagnostic accuracy. This review provides a comprehensive overview of the current evidence regarding evolving diagnostic methods in ILD and to consider their future role in routine clinical care.

Genetics in Idiopathic Pulmonary Fibrosis: A Clinical Perspective

BACKGROUND

Unraveling the genetic background in a significant proportion of patients with both sporadic and familial IPF provided new insights into the pathogenic pathways of pulmonary fibrosis.

AIM

The aim of the present study is to overview the clinical significance of genetics in IPF.

PERSPECTIVE

It is fascinating to realize the so-far underestimated but dynamically increasing impact that genetics has on aspects related to the pathophysiology, accurate and early diagnosis, and treatment and prevention of this devastating disease. Genetics in IPF have contributed as no other in unchaining the disease from the dogma of a "a sporadic entity of the elderly, limited to the lungs" and allowed all scientists, but mostly clinicians, all over the world to consider its many aspects and "faces" in all age groups, including its co-existence with several extra pulmonary conditions from cutaneous albinism to bone-marrow and liver failure.

CONCLUSION

By providing additional evidence for unsuspected characteristics such as immunodeficiency, impaired mucus, and surfactant and telomere maintenance that very often co-exist through the interaction of common and rare genetic variants in the same patient, genetics have created a generous and pluralistic yet unifying platform that could lead to the understanding of the injurious and pro-fibrotic effects of many seemingly unrelated extrinsic and intrinsic offending factors. The same platform constantly instructs us about our limitations as well as about the heritability, the knowledge and the wisdom that is still missing.

A Risk Score to Detect Subclinical Rheumatoid Arthritis-Associated Interstitial Lung Disease

OBJECTIVE

Patients at high risk of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) would benefit from being identified before the onset of respiratory symptoms; this can be done by screening patients with the use of chest high-resolution computed tomography (HRCT). Our objective was to develop and validate a risk score for patients who have subclinical RA-ILD.

METHODS

Our study included a discovery population and a replication population from 2 prospective RA cohorts (ESPOIR and TRANSLATE2, respectively) without pulmonary symptoms who had received chest HRCT scans. All patients were genotyped for MUC5B rs35705950. After multiple logistic regression, a risk score based on independent risk factors for subclinical RA-ILD was developed in the discovery population and tested for validation in the replication population.

RESULTS

The discovery population included 163 patients with RA, and the replication population included 89 patients with RA. The prevalence of subclinical RA-ILD was 19.0% and 16.9%, respectively. In the discovery population, independent risk factors for subclinical RA-ILD were presence of the MUC5B rs35705950 T allele (odds ratio [OR] 3.74 [95% confidence interval (95% CI) 1.37, 10.39]), male sex (OR 3.93 [95% CI 1.40, 11.39]), older age at RA onset (for each year, OR 1.10 [95% CI 1.04, 1.16]), and increased mean Disease Activity Score in 28 joints using the erythrocyte sedimentation rate (for each unit, OR 2.03 [95% CI 1.24, 3.42]). We developed and validated a derived risk score with receiver operating characteristic areas under the curve of 0.82 (95% CI 0.70-0.94) for the discovery population and 0.78 (95% CI 0.65-0.92) for the replication population. Excluding MUC5B rs35705950 from the model provided a lower goodness of fit (likelihood ratio test, P = 0.01).

CONCLUSION

We developed and validated a risk score that could help identify patients at high risk of subclinical RA-ILD. Our findings support an important contribution of MUC5B rs35705950 to subclinical RA-ILD risk.

Compound heterozygous mutation of RTEL1 in interstitial lung disease complicated with pneumothorax and emphysema: A case report and literature review

Interstitial lung diseases (ILDs) are common respiratory diseases with limited treatment options and poor prognoses. Early and accurate diagnosis of ILD is challenging and requires a multidisciplinary discussion. We report a 32‐year‐old patient admitted to our hospital with cough and increasing dyspnea on exertion. Computerized tomography scan of his chest demonstrated diffuse interstitial abnormalities, emphysematous changes, and a pneumothorax. Whole‐exome sequencing (WES) and Sanger sequencing indicated a compound mutation of heterozygosity in RTEL1 gene c.2992C > T(p.Arg998*) and c.482T > C(p.Val161Ala). In‐silicon analysis revealed the pathogenic nonsense mutation c.2992C > T, which introduced a premature stop codon in exon 30 of RTEL1. The patient is still alive with progressive dyspnea to now. We reviewed the pathophysiology of ILD patients carrying RTEL1 mutations and the roles of RTEL1 mutation in guiding treatment and prognostication in ILD.

Role of Circular RNAs in Pulmonary Fibrosis

Pulmonary fibrosis is a chronic progressive form of interstitial lung disease, characterized by the histopathological pattern of usual interstitial pneumonia. Apart from aberrant alterations of protein-coding genes, dysregulation of non-coding RNAs, including microRNAs, long non-coding RNAs, and circular RNAs (circRNAs), is crucial to the initiation and progression of pulmonary fibrosis. CircRNAs are single-stranded RNAs that form covalently closed loops without 5′ caps and 3′ tails. Different from canonical splicing of mRNA, they are produced from the back-splicing of precursor mRNAs and have unique biological functions, as well as potential biomedical implications. They function as important gene regulators through multiple actions, including sponging microRNAs and proteins, regulating transcription, and splicing, as well as protein-coding and translation in a cap-independent manner. This review comprehensively summarizes the alteration and functional role of circRNAs in pulmonary fibrosis, with a focus on the involvement of the circRNA in the context of cell-specific pathophysiology. In addition, we discuss the diagnostic and therapeutic potential of targeting circRNA and their regulatory pathway mediators, which may facilitate the translation of recent advances from bench to bedside in the future.

Interstitial lung diseases

Over 200 interstitial lung diseases, from ultra rare to relatively common, are recognised. Most interstitial lung diseases are characterised by inflammation or fibrosis within the interstitial space, the primary consequence of which is impaired gas exchange, resulting in breathlessness, diminished exercise tolerance, and decreased quality of life. Outcomes vary considerably for each of the different interstitial lung diseases. In some conditions, spontaneous reversibility or stabilisation can occur, but unfortunately in many people with interstitial lung disease, especially in those manifesting progressive pulmonary fibrosis, respiratory failure and death are a sad reality. Over the past 3 years, the field of interstitial lung disease has had important advances, with the approval of drugs to treat systemic sclerosis-associated interstitial lung disease, interstitial lung disease-associated pulmonary hypertension, and different forms of progressive pulmonary fibrosis. This Seminar provides an update on epidemiology, pathogenesis, presentation, diagnosis, disease course, and management of the interstitial lung diseases that are most frequently encountered in clinical practice. Furthermore, we describe how developments have led to a shift in the classification and treatment of interstitial lung diseases that exhibit progressive pulmonary fibrosis and summarise the latest practice-changing guidelines. We conclude with an outline of controversies, uncertainties, and future directions.

The value of fractional exhaled nitric oxide in occupational diseases - a systematic review

Fractional exhaled nitric oxide (FeNO) is a non-invasive biomarker of respiratory tract inflammation, originally designated to identify eosinophilic airway inflammation and to predict steroid response. The main field of application of this biomarker is asthma, but FeNO has also been used for other allergic and non-allergic pulmonary disorders such as chronic obstructive pulmonary disease, hypersensitivity pneumonitis and interstitial lung disease. A substantial part of respiratory diseases are related to work, and FeNO, a safe and easy measure to conduct, is a potential valid examination in an occupational setting.

This systematic review assesses the value of measuring FeNO related to three types of airborne exposures: allergens, irritants, and respiratory particles inhaled during occupational activities. The review covers results from longitudinal and observational clinical studies, and highlights the added value of this biomarker in monitoring effects of exposure and in the diagnostic criteria of occupational diseases. This review also covers the possible significance of FeNO as an indicator of the efficacy of interventions to prevent work-related respiratory diseases.

Initially, 246 articles were identified in PUBMED and SCOPUS. Duplicates and articles which covered results from the general population, symptoms (not disease) related to work, non-occupational diseases, and case reports were excluded. Finally, 39 articles contributed to this review, which led to the following conclusions:

a) For occupational asthma there is no consensus on the significant value of FeNO for diagnosis, or on the magnitude of change needed after specific inhalation test or occupational exposure at the workplace. There is some consensus for the optimal time to measure FeNO after exposure, mainly after 24 h, and FeNO proved to be more sensitive than spirometry in measuring the result of an intervention. b) For other occupational obstructive respiratory diseases, current data suggests performing the measurement after the work shift. c) For interstitial lung disease, the evaluation of the alveolar component of NO is probably the most suitable.

Integrated analysis of single-cell and bulk RNA sequencing reveals pro-fibrotic PLA2G7high macrophages in pulmonary fibrosis

Pulmonary fibrosis (PF) is the pathological change of end-stage interstitial lung diseases with high mortality and limited therapeutic options. Lung macrophages have distinct subsets with divergent functions, and play critical roles in the pathogenesis of PF. In this study, integrative analysis of lung single-cell and bulk RNA-seq data from patients with fibrotic hypersensitivity pneumonitis and idiopathic pulmonary fibrosis was utilized to identify particular macrophage subsets during the development of PF. We find a specific macrophage subpopulation highly expressing PLA2G7 in fibrotic lungs. We performed additional single-cell RNA-seq analysis to identify analogous macrophage population in bleomycin (BLM)-induced mouse pulmonary fibrosis models. By in vitro and in vivo experiments, we further reveal the pro-fibrotic role for this PLA2G7^high macrophage subset in fibroblast-to-myofibroblast transition (FMT) during pulmonary fibrosis. PLA2G7 promotes FMT via LPC/ATX/LPA/LPA2 axis in macrophages. Moreover, PLA2G7 is regulated by STAT1, and pharmacological inhibition of PLA2G7 by Darapladib ameliorates pulmonary fibrosis in BLM-induced mice. The results of this study support the view that PLA2G7^high macrophage subpopulation contributes importantly to the pathogenesis of PF, which provides a potential way for targeted therapy.

[68 Ga]Ga-FAPI-46 PET for non-invasive detection of pulmonary fibrosis disease activity

PURPOSE

The lack of effective molecular biomarkers to monitor idiopathic pulmonary fibrosis (IPF) activity or treatment response remains an unmet clinical need. Herein, we determined the utility of fibroblast activation protein inhibitor for positron emission tomography (FAPI PET) imaging in a mouse model of pulmonary fibrosis.

METHODS

Pulmonary fibrosis was induced by intratracheal administration of bleomycin (1 U/kg) while intratracheal saline was administered to control mice. Subgroups from each cohort (n = 3-5) underwent dynamic 1 h PET/CT after intravenously injecting FAPI-46 radiolabeled with gallium-68 ([⁶⁸ Ga]Ga-FAPI-46) at 7 days and 14 days following disease induction. Animals were sacrificed following imaging for ex vivo gamma counting and histologic correlation. [⁶⁸ Ga]Ga-FAPI-46 uptake was quantified and reported as percent injected activity per cc (%IA/cc) or percent injected activity (%IA). Lung CT density in Hounsfield units (HU) was also correlated with histologic examinations of lung fibrosis.

RESULTS

CT only detected differences in the fibrotic response at 14 days post-bleomycin administration. [⁶⁸ Ga]Ga-FAPI-46 lung uptake was significantly higher in the bleomycin group than in control subjects at 7 days and 14 days. Significantly (P = 0.0012) increased [⁶⁸ Ga]Ga-FAPI-46 lung uptake in the bleomycin groups at 14 days (1.01 ± 0.12%IA/cc) vs. 7 days (0.33 ± 0.09%IA/cc) at 60 min post-injection of the tracer was observed. These findings were consistent with an increase in both fibrinogenesis and FAP expression as seen in histology.

CONCLUSION

CT was unable to assess disease activity in a murine model of IPF. Conversely, FAPI PET detected both the presence and activity of lung fibrogenesis, making it a promising tool for assessing early disease activity and evaluating the efficacy of therapeutic interventions in lung fibrosis patients.

Real-life prevalence of progressive fibrosing interstitial lung diseases

The concept of progressive fibrosing interstitial lung disease (PF-ILD) has recently emerged. However, real-life proportion of PF-ILDs outside IPF is still hard to evaluate. Therefore, we sought to estimate the proportion of PF-ILD in our ILD cohort. We also determined the proportion of ILD subtypes within PF-ILD and investigated factors associated with PF-ILDs. Finally, we quantified interobserver agreement between radiologists for the assessment of fibrosis. We reviewed the files of ILD patients discussed in multidisciplinary discussion between January 1st 2017 and December 31st 2019. Clinical data, pulmonary function tests (PFTs) and high-resolution computed tomography (HRCTs) were centrally reviewed. Fibrosis was defined as the presence of traction bronchiectasis, reticulations with/out honeycombing. Progression was defined as a relative forced vital capacity (FVC) decline of ≥ 10% in ≤ 24 months or 5% < FVC decline < 10% and progression of fibrosis on HRCT in ≤ 24 months. 464 consecutive ILD patients were included. 105 had a diagnosis of IPF (23%). Most frequent non-IPF ILD were connective tissue disease (CTD)-associated ILD (22%), hypersensitivity pneumonitis (13%), unclassifiable ILD (10%) and sarcoidosis (8%). Features of fibrosis were common (82% of CTD-ILD, 81% of HP, 95% of uILD). After review of HRCTs and PFTs, 68 patients (19% of non-IPF ILD) had a PF-ILD according to our criteria. Interobserver agreement for fibrosis between radiologists was excellent (Cohen’s kappa 0.86). The main diagnosis among PF-ILD were CTD-ILD (36%), HP (22%) and uILD (20%). PF-ILD patients were significantly older than non-F-ILD (P = 0.0005). PF-ILDs represent about 20% of ILDs outside IPF. This provides an estimation of the proportion of patients who might benefit from antifibrotics. Interobserver agreement between radiologists for the diagnosis of fibrotic ILD is excellent.

Molecular Mechanisms and Cellular Contribution from Lung Fibrosis to Lung Cancer Development

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrosing interstitial lung disease (ILD) of unknown aetiology, with a median survival of 2–4 years from the time of diagnosis. Although IPF has unknown aetiology by definition, there have been identified several risks factors increasing the probability of the onset and progression of the disease in IPF patients such as cigarette smoking and environmental risk factors associated with domestic and occupational exposure. Among them, cigarette smoking together with concomitant emphysema might predispose IPF patients to lung cancer (LC), mostly to non-small cell lung cancer (NSCLC), increasing the risk of lung cancer development. To this purpose, IPF and LC share several cellular and molecular processes driving the progression of both pathologies such as fibroblast transition proliferation and activation, endoplasmic reticulum stress, oxidative stress, and many genetic and epigenetic markers that predispose IPF patients to LC development. Nintedanib, a tyrosine–kinase inhibitor, was firstly developed as an anticancer drug and then recognized as an anti-fibrotic agent based on the common target molecular pathway. In this review our aim is to describe the updated studies on common cellular and molecular mechanisms between IPF and lung cancer, knowledge of which might help to find novel therapeutic targets for this disease combination.

High intensity interval training versus moderate intensity continuous training for people with interstitial lung disease: protocol for a randomised controlled trial

Background

Interstitial lung disease is a debilitating condition associated with significant dyspnoea, fatigue, and poor exercise tolerance. Pulmonary rehabilitation is an effective and key intervention in people with interstitial lung disease. However, despite the best efforts of patients and clinicians, many of those who participate are not achieving clinically meaningful benefits. This assessor-blinded, multi-centre, randomised controlled trial aims to compare the clinical benefits of high intensity interval exercise training versus the standard pulmonary rehabilitation method of continuous training at moderate intensity in people with fibrotic interstitial lung disease.

Methods

Eligible participants will be randomised to either a standard pulmonary rehabilitation group using moderate intensity continuous exercise training or high intensity interval exercise training. Participants in both groups will undertake an 8-week pulmonary rehabilitation program of twice-weekly supervised exercise training including aerobic (cycling) and strengthening exercises. In addition, participants in both groups will be prescribed a home exercise program.

Outcomes will be assessed at baseline, upon completion of the intervention and at six months following the intervention by a blinded assessor. The primary outcome is endurance time on a constant work rate test. Secondary outcomes are functional capacity (6-min walk distance), health-related quality of life (Chronic Respiratory Disease Questionnaire (CRQ), St George’s Respiratory Questionnaire idiopathic pulmonary fibrosis specific version (SGRQ-I), breathlessness (Dyspnoea 12, Modified Medical Research Council Dyspnoea Scale), fatigue (fatigue severity scale), anxiety (Hospital Anxiety and Depression Scale), physical activity level (GeneActiv), skeletal muscle changes (ultrasonography) and completion and adherence to pulmonary rehabilitation.

Discussion

The standard exercise training strategies used in pulmonary rehabilitation may not provide an optimal exercise training stimulus for people with interstitial lung disease. This study will determine whether high intensity interval training can produce equivalent or even superior changes in exercise performance and symptoms. If high intensity interval training proves effective, it will provide an exercise training strategy that can readily be implemented into clinical practice for people with interstitial lung disease.

Trial registration ClinicalTrials.gov Registry (NCT03800914). Registered 11 January 2019, https://clinicaltrials.gov/ct2/show/NCT03800914

Australian New Zealand Clinical Trials Registry ACTRN12619000019101. Registered 9 January 2019, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=376050&isReview=true