Fibrosing interstitial lung diseases: knowns and unknowns

Tryptanthrin alleviate lung fibrosis via suppression of MAPK/NF-κB and TGF-β1/SMAD signaling pathways in vitro and in vivo

Idiopathic pulmonary fibrosis (IPF), a progressive interstitial lung disease of unknown etiology, remains a therapeutic challenge with limited treatment options. This study investigates the therapeutic potential and molecular mechanisms of Tryptanthrin, a bioactive indole quinazoline alkaloid derived from Isatis tinctoria L., in pulmonary fibrosis. In a bleomycin-induced murine IPF model, Tryptanthrin administration (5 and 10 mg/kg/day for 28 days) significantly improved pulmonary function parameters and attenuated histological evidence of fibrosis. Mechanistic analysis revealed dual pathway modulation: Tryptanthrin suppressed MAPK/NF-κB signaling through inhibition of phosphorylation events, subsequently reducing pulmonary levels of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6). Concurrently, it attenuated TGF-β1/Smad pathway activation by decreasing TGF-β1 expression and Smad2/3 phosphorylation, thereby downregulating fibrotic markers including COL1A1, α-smooth muscle actin (α-SMA), and fibronectin in lung tissues. Complementary in vitro studies using Lipopolysaccharide (LPS) or TGF-β1-stimulated NIH3T3 fibroblasts confirmed these anti-inflammatory and anti-fibrotic effects through analogous pathway inhibition. Our findings demonstrate that Tryptanthrin exerts therapeutic effects against pulmonary fibrosis via coordinated modulation of both inflammatory (MAPK/NF-κB) and fibrotic (TGF-β1/Smad) signaling cascades, suggesting its potential as a novel multi-target therapeutic agent for IPF management.

CD45+/ Col I+ Fibrocytes: Major source of collagen in the fibrotic lung, but not in passaged fibroblast cultures

The role of cells of the hematopoietic lineage in fibrosis is controversial. Here we evaluate the contribution of Col I+/CD45+ cells (fibrocytes) to lung fibrosis. Systemic bleomycin treatment was used to induce fibrosis in a bone marrow transplant and two transgenic mouse models. Lung cells from these mice were analyzed by flow cytometry, both immediately upon release from the tissue or following growth on tissue-culture plastic. Fibrotic and control human lung tissue were also used. Fibroblasts and fibrocytes derived from a transgenic mouse model were compared in terms of their morphology, growth, and adhesion to fibronectin. Single cell RNAseq was performed with the analysis focusing on CD45-/Col I+ "fibroblasts" and CD45+/Col I+ "fibrocytes" in control and fibrotic mouse lung tissue. Finally, we inhibited fibrosis in mice using a novel, water-soluble version of caveolin scaffolding domain (CSD) called WCSD. In both mouse and human lung tissue, we observed by flow cytometry a large increase in fibrocyte number and Col I expression associated with fibrosis. In contrast, fibroblast number was not significantly increased. A large increase (>50-fold) in fibrocyte number associated with fibrosis was also observed by single cell RNAseq. In this case, fibroblasts increased 5-fold. Single cell RNAseq also revealed that myofibroblast markers in fibrotic tissue are associated with a cluster containing a similar number of fibrocytes and fibroblasts, not with a resident fibroblast cluster. Some investigators claim that fibrocytes are not present among primary fibroblasts. However, we found that fibrocytes were the predominant cell type present in these cultures prior to passage. Fewer fibrocytes were present after one passage, and almost none after two passages. Our experiments suggest that fibrocytes are crowded out of cultures during passage because fibroblasts have a larger footprint than fibrocytes, even though fibrocytes bind more efficiently to fibronectin. Finally, we observed by flow cytometry that in mice treated with bleomycin and WCSD compared to bleomycin alone, there was a large decrease in the number of fibrocytes present but not in the number of fibroblasts. In summary, fibrocytes are a major collagen-producing cell type that is increased in number in association with fibrosis as well as a major source of myofibroblasts. The common observation that collagen-producing spindle-shaped cells associated with fibrosis are CD45- may be an artifact of passage in cell culture.

Retrospective Analysis of Predictive Biomarkers of Survival in Acute Exacerbation of Fibrosing Interstitial Lung Disease: A Single-Center Study in Spain

Background: Fibrosing interstitial lung diseases can evolve into acute exacerbations, which significantly impact morbidity and mortality. Currently, no routinely used clinical biomarkers can discern the potential progression in these patients. This study aims to analyze different biological markers used in routine clinical practice as possible predictive biomarkers for patients with acute fibrosing interstitial lung disease exacerbation. Methods: We conducted a retrospective, single-center study including patients diagnosed with acute exacerbation of fibrosing interstitial lung disease who required hospitalization between 2018 and 2019 at Vall d'Hebron Hospital, Spain. Patient demographics, clinical data, respiratory function, and comorbidities were collected at baseline. The primary outcome was survival at 30 days, 90 days, and 365 days, using Kaplan-Meier survival analysis and Cox regression. Results: Twenty-nine patients were included (mean age 70.4 years). At the 3-month follow-up, patients with ischemic heart disease showed higher survival rates (p = 0.02). Identifying an infection as the etiology of the exacerbation was associated with worse one-year survival rates compared to idiopathic cases (p = 0.03). Elevated levels of leukocytes (p < 0.01), neutrophils (p < 0.01), and fibrinogen (p = 0.03) were predictors of mortality. Additionally, patients who received a cumulative dose of corticosteroids between 501 and 1000 mg during the exacerbation showed higher one-year survival (p < 0.01). Conclusions: Routine clinical markers can help predict outcomes in AE-f-ILD. Further multicenter studies should validate these findings and assess the role of therapies in its management.

Epidemiology of idiopathic pulmonary fibrosis in central and Western Pennsylvania

BACKGROUND/RATIONALE

Idiopathic Pulmonary Fibrosis (IPF) is a chronic, progressive disease of unknown origin. Establishing the epidemiology of IPF has been challenging due to diagnostic complexity, poor survival, low prevalence, and heterogeneity of ascertainment methodologies.

OBJECTIVES

This research aimed to estimate the rates of IPF in central and western Pennsylvania and to pilot the use of capture recapture (CR) methods to estimate the disease incidence.

METHODS

We identified adults ≥ 30 years old diagnosed with IPF (by ICD-9/10 coding) between 2013 to 2021 from two health systems (UPMC Health System and Penn State Health) participating in the PaTH Clinical Research Network. We extracted information on patients' sex, race, date of birth and 3-digit zip code from electronic health records (EHR). Incidence rate of IPF among Pennsylvania residents was calculated using three case definitions (broad and two restricted) and piloted the use of CR in estimating IPF incidence.

RESULTS

IPF incidence rates were 8.42, 6.95 and 4.4 per 100,000 person-years for the unrestricted (n = 3148), partially restricted (n = 2598) and fully restricted (n = 1661) samples, respectively. Low case overlap between two sites resulted in a highly inflated estimate of IPF incidence, using the CR methodology.

CONCLUSIONS

The rate of IPF in central and western Pennsylvania was similar to previously published statistics. The application of CR to IPF epidemiology could be further investigated in health systems with greater overlap of patients utilizing more than one system.

Diagnosis of Fibrotic Interstitial Lung Diseases Based on the Combination of Label-Free Quantitative Multiphoton Fiber Histology and Machine Learning

Interstitial lung disease (ILD), characterized by inflammation and fibrosis, often suffers from low diagnostic accuracy and consistency. Traditional hematoxylin and eosin (H&E) staining primarily reveals cellular inflammation with limited detail on fibrosis. To address these issues, we introduce a pioneering label-free quantitative multiphoton fiber histology (MPFH) technique that delineates the intricate characteristics of collagen and elastin fibers for ILD diagnosis. We acquired colocated multiphoton and H&E-stained images from a single tissue slice. Multiphoton imaging was performed on the deparaffinized section to obtain fibrotic tissue information, followed by H&E staining to capture cellular information. This approach was tested in a blinded diagnostic trial among 7 pathologists involving 14 patients with relatively normal lung and 31 patients with ILD (11 idiopathic pulmonary fibrosis/usual interstitial pneumonia, 14 nonspecific interstitial pneumonia, and 6 pleuroparenchymal fibroelastosis). A customized algorithm extracted quantitative fiber indicators from multiphoton images. These indicators, combined with clinical and radiologic features, were used to develop an automatic multiclass ILD classifier. Using MPFH, we can acquire high-quality, colocalized images of collagen fibers, elastin fibers, and cells. We found that the type, distribution, and degree of fibrotic proliferation can effectively distinguish between different subtypes. The blind study showed that MPFH enhanced diagnostic consistency (κ values from 0.56 to 0.72) and accuracy (from 73.0% to 82.5%, P = .0090). The combination of quantitative fiber indicators effectively distinguished between different tissues, with areas under the receiver operating characteristic curves exceeding 0.92. The automatic classifier achieved 93.8% accuracy, closely paralleling the 92.2% accuracy of expert pathologists. The outcomes of our research underscore the transformative potential of MPFH in the field of fibrotic-ILD diagnostics. By integrating quantitative analysis of fiber characteristics with advanced machine learning algorithms, MPFH facilitates the automatic and accurate identification of various fibrotic disease subtypes, showcasing a significant leap forward in precision diagnostics.

Supplemental oxygen therapy use among patients with fibrosing interstitial lung disease in the United States

BACKGROUND

Supplemental oxygen therapy is commonly prescribed in clinical practice for patients with fibrosing interstitial lung disease (ILD) to reduce breathlessness and increase physical capacity. Only a few studies have evaluated the incidence of oxygen therapy use, with evidence lacking in its use among fibrosing ILD subtypes including patients with idiopathic pulmonary fibrosis (IPF) and non-IPF ILD. This study aimed to estimate incidence of oxygen therapy and factors associated with oxygen therapy initiation.

METHODS

This non-interventional study used US administrative claims and electronic health record data from 01 October 2015 to 30 June 2022. Patients aged ≥ 18 years with newly diagnosed fibrosing ILD (≥ 2 fibrosing ILD diagnoses in any position on different dates of service within 365 days) were included; the index date was the first date with ILD diagnosis. Patients were followed until the earlier of health plan disenrollment, death, or end of study period. Oxygen therapy use was evaluated among patients without evidence of oxygen therapy before the index date, stratified by the underlying fibrosing disease (i.e., IPF vs. non-IPF ILD). Factors associated with oxygen therapy use were evaluated using Cox proportional hazards regression.

RESULTS

A total of 114,921 patients (IPF n = 5,555; non-IPF ILD n = 109,366) newly diagnosed with fibrosing ILD were included in the study. The mean (standard deviation) age of patients with ILD was 66.9 (14.2) years, and 47.2% were male. Patients were followed for a mean of 24 months after ILD diagnosis, during which 38% of fibrosing ILD patients initiated oxygen therapy; a higher proportion of patients with IPF initiated oxygen therapy compared to those with non-IPF ILD (68% and 36%, respectively). Factors associated with oxygen therapy initiation included IPF, higher Charlson comorbidity scores, and comorbidities that impair respiratory capacity.

CONCLUSIONS

The study findings demonstrate a substantial proportion of patients with fibrosing ILD initiated oxygen therapy following initial ILD diagnosis, with higher rates of oxygen therapy initiation observed among patients with IPF compared with non-IPF ILD. Respiratory comorbidities were key factors associated with increased initiation of oxygen therapy.

Interstitial Lung Abnormalities: Unraveling the Journey from Incidental Discovery to Clinical Significance

Interstitial lung abnormalities (ILAs) are incidental radiologic abnormalities on chest computed tomography (CT) examination performed on people in whom interstitial lung disease (ILD) is not suspected. Despite the fact that most of these individuals are asymptomatic, ILAs are not synonymous with subclinical ILD, as a subset of them have symptoms and lung function impairment. On the other hand, not all ILAs progress to clinically significant ILD. Specific imaging features and patterns have been proven more likely to progress, while some individuals may comprise a higher risk group for progression. Numerous studies have demonstrated that ILAs are not only associated with an increased risk of progression toward pulmonary fibrosis and fibrosis-related mortality but are also linked to a greater incidence of lung cancer and a higher rate of all-cause mortality. Considering that the systematic evaluation of large cohorts has shown a prevalence of ILAs up to 7% and that the natural history of ILAs is unclear, successful screening and appropriate monitoring of ILAs is of particular significance for earlier diagnosis, risk factor modification, and treatment. The present review aims to summarize the current knowledge on ILAs and highlight the need to define those at greatest risk of progression to ILD and worse clinical outcomes.

Luteolin: exploring its therapeutic potential and molecular mechanisms in pulmonary diseases

Luteolin is a flavonoid widely found in plants, including vegetables, botanical drugs, and fruits. Owing to its diverse pharmacological activities, such as anticancer, oxidative stress protection, anti-inflammatory, and neuron-preserving effects, luteolin has attracted attention in research and medicine. Luteolin exhibits therapeutic effects on various pulmonary disease models through multiple molecular mechanisms; these include inhibition of activation of the PI3K/Akt-mediated Nuclear Factor kappa-B (NF-κB) and MAPK signaling pathways, as well as the promotion of regulatory T cell (Treg) function and enhancement of alveolar epithelial sodium channel (ENaC) activity (alleviating inflammation and oxidative stress responses). Luteolin has therapeutic effects on chronic obstructive pulmonary disease (COPD), acute lung injury/acute respiratory distress syndrome (ALI/ARDS), pulmonary fibrosis, allergic asthma, and lung cancer. Luteolin, a naturally occurring polyphenol, is poorly water-soluble. The oral route may be ineffective because the gut poorly absorbs this type of flavonoid. Therefore, although luteolin exhibits significant biological activity, its clinical application is limited by challenges associated with its poor water solubility and low bioavailability, which are critical factors for its efficacy and pharmacological application. These challenges can be addressed by modifying the chemical structure and enhancing pharmaceutical formulations. We summarized the research advancements in improving the solubility and bioavailability of luteolin, as well as the effects of luteolin on various pulmonary diseases and their related mechanisms, with the aim of providing new ideas for researchers.

Development of the pulmonary fibrosis, pulmonary vascular resistance, six minute walk distance, B-type natriuretic peptide, age (PVD-B65) risk score for patients with chronic lung disease and pulmonary hypertension

BACKGROUND

Pulmonary hypertension (PH) confers increased mortality in patients with chronic lung disease, yet there remains a lack of validated risk assessment tools to prognosticate these patients. We aimed to create a risk assessment tool to stratify patients with chronic lung disease and PH by risk of one-year mortality from time of PH diagnosis.

METHODS

This was a retrospective cohort study of patients with chronic lung disease and PH. We identified predictors of one-year mortality via multivariable Cox regression and assigned point values to the identified predictors based on their hazard ratios to comprise the risk score. Patients were stratified into low, intermediate, and high-risk based on total scores. Kaplan-Meier survival analysis comparing the stratified groups was performed. Internal statistical validation was performed via Cox regression with bootstrapping.

RESULTS

The identified predictors of one-year mortality that comprised our risk assessment tool were pulmonary fibrosis without emphysema, pulmonary vascular resistance > 5 WU, six-minute walk distance < 150 m, BNP > 200 pg/mL, and age > 65 years (PVD-B65). Once patients were stratified into the three risk groups, Kaplan-Meier survival analysis demonstrated significant differences in one-year survival between the subgroups (logrank p = 0.002). The risk assessment model demonstrated internal validation via bootstrapping (p < 0.05).

CONCLUSION

The PVD-B65 risk assessment tool is a novel, internally validated one-year mortality risk calculator for patients with chronic lung disease and PH that encompasses factors related to pulmonary parenchymal and vascular remodeling. It may help risk stratify and guide therapeutic interventions in patients with chronic lung disease and PH.

Reference values for the 1-minute sit-to-stand test to assess functional capacity and short-term mortality in people with idiopathic pulmonary fibrosis and fibrotic connective tissue related interstitial lung diseases: a prospective real-world cohort study

BACKGROUND

Early identification of functional decline in fibrotic interstitial lung disease (F-ILD) is crucial for timely treatment and improved survival. While the 6-minute walk test (6MWT) is the standard for functional evaluation, it has practical limitations. The 1-minute sit-to-stand test (1MSTS) offers a simpler alternative; however, its correlation with the 6MWT in F-ILD patients remains unclear. This study aims to establish reference values for the 1MSTS in assessing functional capacity, evaluate its correlation with the 6MWT, and explore its utility in predicting 18-month mortality in F-ILD patients.

METHODS

This prospective study enrolled participants diagnosed with F-ILD based on multidisciplinary team discussions. Assessments included the 1MSTS, 6MWT, pulmonary function test (PFT), GAP score, mMRC scale, and Charlson Comorbidity Index (CCI). The association between 1MSTS repetitions and other variables was calculated using Spearman's rho. Bland-Altman plots assessed the agreement between 1MSTS repetitions and the 6MWT. Predictors of 18-month mortality were evaluated using ROC curve and Kaplan-Meier curve.

RESULTS

Of the 150 F-ILD patients, 37 (24.6%) had idiopathic pulmonary fibrosis (IPF), and 113 (75.4%) had connective tissue disease-related ILD (CTD-ILD). Using ≤ 23 repetitions as the cutoff for functional impairment in 1MSTS, 74 (47.3%) patients were classified as impaired. The 1MSTS significantly predicted 18-month mortality and demonstrated moderate correlations with GAP score (rs = -0.49), mMRC scale (rs = -0.47), and 6MWT distance (rs = 0.65). Bland-Altman analysis indicated agreement between 1MSTS repetitions and 6MWT distance. Using ≤ 23 repetitions as the cutoff value for the 1MSTS to predict 18-month mortality, the mortality rate was 76.4%, with an AUC of 0.81.

CONCLUSIONS

The findings suggest that ≤ 23 repetitions in the 1MSTS can serve as an indicator of functional impairment, demonstrate a good correlation with 6MWT distance, and effectively predict 18-month mortality in patients with F-ILD.

CLINICAL TRIAL NUMBER

Not applicable.

Diagnosis, screening, and follow-up of patients with familial interstitial lung disease: Results from an international survey

BACKGROUND

Advances in the field of genetics of interstitial lung diseases (ILDs) have led to the recent consensus statements made by expert groups. International standards for genetic testing in ILD have not yet been established. We aimed to examine current real-world strategies employed by pulmonologists working with familial ILD.

METHODS

A panel of pulmonologists with expertise in ILD developed an international survey aimed at clinicians working with ILD. The survey consisted of 74 questions divided into eight topics: characteristics of respondents, diagnosis, screening of first-degree relatives, screening tools, genetic testing methods, lung transplantation, ethical concerns, and future needs.

RESULTS

Overall, 237 pulmonologists from 50 countries participated. A family history of ILD was asked for by 91% of respondents while fewer asked for symptoms related to telomere disorders. Respondents stated that 59% had access to genetic testing, and 30% to a genetic multidisciplinary team (MDT). Many respondents were unaware of specific genetic testing methods. Pathogenic genetic variants were seen as a potential contraindication for lung transplantation in 6-8% of respondents. Genetic screening of relatives was supported by 80% of respondents who indicated insufficient evidence and a lack of formal guidelines for genetics and ILD. Only 16% had a standardized program.

CONCLUSION

Most pulmonologists ask for a family history of ILD and recommend genetic testing for ILD and screening in relatives but have limited knowledge of specific tests and access to genetic MDT. Evidence-based guidelines to inform patients, relatives, and physicians are still warranted.

Fibrosis in PCLS: comparing TGF-β and fibrotic cocktail

INTRODUCTION

Fibrotic cocktail (FC) is a combination of pro-fibrotic and pro-inflammatory mediators that induces early fibrotic changes in organotypic lung models. We hypothesised that transforming growth factor beta 1 (TGF-β1) alone induces a pro-fibrotic effect similar to FC. Our aim was to compare the pro-fibrotic effects of TGF-β1 with FC in human precision-cut lung slices (PCLS).

METHODS

PCLS from "healthy" lung tissue of cancer patients undergoing surgery (n = 7) were incubated with TGF-β1, FC or control for 72 h. Gene expression markers for myofibroblasts differentiation, extracellular matrix (ECM), as well as TGF-β receptors were assessed (RT-qPCR). ECM proteins expression in lysates and supernatant was assessed by ELISA and immunofluorescence.

RESULTS

We found that TGF-β1 significantly increased gene expression of ACTA2, COL1A1, CCN2, and VIM compared to control but also compared to FC. FC showed a significant increase of matrix metalloproteinase (MMP) 7 and 1 compared to control, while TGF-β receptor 2 was lower after FC compared to TGF-β1 or control. FC or TGF-β1 showed similar fibronectin protein expression in lysates and supernatants, while type I collagen protein expression in lysates was significantly greater with TGF-β1 compared to control.

CONCLUSIONS

Our findings show that TGF-β1 induces consistent pro-fibrotic changes in PCLS after 72 h. Compared to TGF-β1, FC treatment resulted in reduced gene expression of TGF-β receptor 2 and increased MMPs expression, potentially mitigating the early pro-fibrotic effects. Selecting specific pro-fibrotic stimuli may be preferable depending on the research question and time point of interest in lung fibrosis studies using PCLS.

Cyclic nucleotide phosphodiesterases as drug targets

Cyclic nucleotides are synthesized by adenylyl and/or guanylyl cyclase, and downstream of this synthesis, the cyclic nucleotide phosphodiesterase families (PDEs) specifically hydrolyze cyclic nucleotides. PDEs control cyclic adenosine-3',5'monophosphate (cAMP) and cyclic guanosine-3',5'-monophosphate (cGMP) intracellular levels by mediating their quick return to the basal steady state levels. This often takes place in subcellular nanodomains. Thus, PDEs govern short-term protein phosphorylation, long-term protein expression, and even epigenetic mechanisms by modulating cyclic nucleotide levels. Consequently, their involvement in both health and disease is extensively investigated. PDE inhibition has emerged as a promising clinical intervention method, with ongoing developments aiming to enhance its efficacy and applicability. In this comprehensive review, we extensively look into the intricate landscape of PDEs biochemistry, exploring their diverse roles in various tissues. Furthermore, we outline the underlying mechanisms of PDEs in different pathophysiological conditions. Additionally, we review the application of PDE inhibition in related diseases, shedding light on current advancements and future prospects for clinical intervention. SIGNIFICANCE STATEMENT: Regulating PDEs is a critical checkpoint for numerous (patho)physiological conditions. However, despite the development of several PDE inhibitors aimed at controlling overactivated PDEs, their applicability in clinical settings poses challenges. In this context, our focus is on pharmacodynamics and the structure activity of PDEs, aiming to illustrate how selectivity and efficacy can be optimized. Additionally, this review points to current preclinical and clinical evidence that depicts various optimization efforts and indications.

Cromolyn sodium reduces LPS-induced pulmonary fibrosis by inhibiting the EMT process enhanced by MC-derived IL-13

BACKGROUND

Sepsis is a systemic inflammatory response caused by infection. When this inflammatory response spreads to the lungs, it can lead to acute lung injury (ALI) or more severe acute respiratory distress syndrome (ARDS). Pulmonary fibrosis is a potential complication of these conditions, and the early occurrence of pulmonary fibrosis is associated with a higher mortality rate. The underlying mechanism of ARDS-related pulmonary fibrosis remains unclear.

METHODS

To evaluate the role of mast cell in sepsis-induced pulmonary fibrosis and elucidate its molecular mechanism. We investigated the level of mast cell and epithelial-mesenchymal transition(EMT) in LPS-induced mouse model and cellular model. We also explored the influence of cromolyn sodium and mast cell knockout on pulmonary fibrosis. Additionally, we explored the effect of MC-derived IL-13 on the EMT and illustrated the relationship between mast cell and pulmonary fibrosis.

RESULTS

Mast cell was up-regulated in the lung tissues of the pulmonary fibrotic mouse model compared to control groups. Cromolyn sodium and mast cell knockout decreased the expression of EMT-related protein and IL-13, alleviated the symptoms of pulmonary fibrosis in vivo and in vitro. The PI3K/AKT/mTOR signaling was activated in fibrotic lung tissue, whereas Cromolyn sodium and mast cell knockout inhibited this pathway.

CONCLUSION

The expression level of mast cell is increased in fibrotic lungs. Cromolyn sodium intervention and mast cell knockout alleviate the symptoms of pulmonary fibrosis probably via the PI3K/AKT/mTOR signaling pathway. Therefore, mast cell inhibition is a potential therapeutic target for sepsis-induced pulmonary fibrosis.

Nebulized fentanyl does not improve exercise capacity or dyspnoea in fibrosing interstitial lung disease

Exercise intolerance and exertional dyspnoea are hallmarks of fibrosing interstitial lung disease (FILD) and are associated with worse prognosis and quality of life. Activation of pulmonary vagal afferents influences the ventilatory pattern and contributes to the sensation of dyspnoea. We tested the hypothesis that nebulized fentanyl, which might attenuate aberrant pulmonary afferent activity in FILD, reduces ventilation and dyspnoea while extending exercise endurance time (EET). In this randomized, single-blind, placebo-controlled study, eight FILD patients (two males, 71 ± 6 years of age) performed incremental cardiopulmonary cycle exercise tests following nebulization of either fentanyl citrate (100 µg) or 0.9% saline. Previous work indicated that this dose was unlikely to produce central effects. Comparisons between treatment conditions at rest were undertaken using Student's paired t-test, and exercise data were evaluated with two-way ANOVA with repeated measures. Dyspnoea was assessed using the Borg dyspnoea scale. Resting respiratory variables were not different following treatment with fentanyl and saline; however, resting heart rate was lower following fentanyl (P = 0.002) and remained lower throughout exercise compared with placebo (P = 0.008). Fentanyl did not increase EET (placebo 334 ± 117 s vs. fentanyl 348 ± 126 s, P = 0.250) although overall minute ventilation was reduced slightly (mean difference: -0.97 L/min, P = 0.022). There were no differences in ratings of dyspnoea intensity or unpleasantness between the conditions either at rest or at end-exercise. Nebulized fentanyl did not improve EET or exercise dyspnoea but did decrease minute ventilation during exercise, although the extent of this reduction appears clinically insignificant. These findings suggest that nebulized fentanyl is unlikely to offer significant benefits for enhancing exercise capacity in FILD.

Otilonium bromide ameliorates pulmonary fibrosis in mice through activating phosphatase PPM1A

Pulmonary fibrosis (PF) is a chronic, progressive and irreversible interstitial lung disease characterized by unremitting pulmonary myofibroblasts activation, extracellular matrix (ECM) deposition and inflammatory recruitment. PF has no curable medication yet. In this study we investigated the molecular pathogenesis and potential therapeutic targets of PF and discovered drug lead compounds for PF therapy. A murine PF model was established in mice by intratracheal instillation of bleomycin (BLM, 5 mg/kg). We showed that the protein level of pulmonary protein phosphatase magnesium-dependent 1A (PPM1A, also known as PP2Cα) was significantly downregulated in PF patients and BLM-induced PF mice. We demonstrated that TRIM47 promoted ubiquitination and decreased PPM1A protein in PF progression. By screening the lab in-house compound library, we discovered otilonium bromide (OB, clinically used for treating irritable bowel syndrome) as a PPM1A enzymatic activator with an EC50 value of 4.23 μM. Treatment with OB (2.5, 5 mg·kg-1·d-1, i.p., for 20 days) significantly ameliorated PF-like pathology in mice. We constructed PF mice with PPM1A-specific knockdown in the lung tissues, and determined that by targeting PPM1A, OB treatment suppressed ECM deposition through TGF-β/SMAD3 pathway in fibroblasts, repressed inflammatory responses through NF-κB/NLRP3 pathway in alveolar epithelial cells, and blunted the crosstalk between inflammation in alveolar epithelial cells and ECM deposition in fibroblasts. Together, our results demonstrate that pulmonary PPM1A activation is a promising therapeutic strategy for PF and highlighted the potential of OB in the treatment of the disease.

Diagnostic and prognostic implications of family history of fibrotic interstitial lung diseases

BACKGROUND

Patients with familial fibrotic interstitial lung disease (ILD) experience worse survival than patients with sporadic disease. Current guidelines do not consider family aggregation or genetic information in the diagnostic algorithm for idiopathic pulmonary fibrosis or other fibrotic ILDs. Better characterizing familial cases could help in diagnostic and treatment decision-making.

METHODS

This retrospective cohort study included 222 patients with fibrotic ILD (104 familial and 118 sporadic) from Bellvitge University Hospital. Clinical, radiological, pulmonary functional tests (PFT), and histological evaluations were performed at diagnosis and follow-up. Telomere shortening and disease-associated variants (DAVs) in telomerase-related genes were analysed in familial patients and sporadic patients with telomeric clinical signs. Primary outcomes were the presence of a UIP histological pattern and disease progression.

RESULTS

Patients with idiopathic pulmonary fibrosis (IPF) (52%), fibrotic hypersensitivity pneumonitis (23%), and other fibrotic ILDs (25%) were included. 42% of patients underwent lung biopsy. Patients with family aggregation were younger and less frequently associated comorbidities, male sex, and smoking history. However, usual interstitial pneumonia (UIP) was more frequent on pathology (p = 0.005; OR 3.37), especially in patients with indeterminate or non-UIP radiological patterns. Despite similar PFT results at diagnosis, familial patients were more likely to present with progressive disease (p = 0.001; OR 3.75). Carrying a DAV increased the risk of fibrotic progression in familial and sporadic patients (p = 0.029, OR 5.01).

DISCUSSION

Familial patients diagnosed with different fibrotic ILDs were more likely to exhibit a histological UIP pattern and disease progression than sporadic patients, independent of radiological findings and pulmonary function at diagnosis.

CONCLUSION

Considering the diagnostic likelihood of the histological UIP pattern and disease outcome, the presence of family aggregation would be useful in the decision making of multidisciplinary committees.

Microplastics, as a risk factor in the development of interstitial lung disease- a preliminary study

Microplastic (MPs) pollution is a global concern that affects all living organisms, yet research on MP-related disorders in humans, including incidence and symptoms, remains limited. In this study, the presence, composition, and characterization of MPs in bronchoalveolar lavage (BAL), which reflects lung tissue, and blood were examined. Fiberoptic bronchoscopy was performed to collect BAL samples from patients suspected of having interstitial lung disease (ILD) as well as from a control group. MPs were identified and measured using μ-Raman techniques. In BAL samples, the most common MPs color observed was grey/white, with sizes ranging from 4.19 to 792.00 μm. The particle shapes and polymer types identified included polyamide (PA), polyester (PET), polyvinyl chloride (PVC), and polyurethanes (PU). For blood samples, MPs were predominantly grey/white and blue, with sizes ranging from 13.14 to 20. 29 μm. The identified polymers in blood samples included polyamide (PA) and polyethylene (PE). MPs were detected in 10 out of 18 patients (55%) suspected of having ILD, with most of these patients presenting with the fibrotic type of the disease. In the control group, two patients whose BAL samples were positive for MPs were found to have chronic lung disease. This study is the first to explore the relationship between interstitial lung disease (ILD) and microplastics (MPs), revealing a tendency for the presence of MPs in the bronchoalveolar lavage (BAL) of ILD patients, particularly those with a fibrotic phenotype. Further research is needed to determine the cumulative effects of MPs on human health, especially concerning the respiratory system, which is highly exposed to environmental pollutants.

Endoplasmic reticulum stress in acute lung injury and pulmonary fibrosis

Pulmonary fibrosis (PF) is a progressive and irreversible lung disease that leads to diminished lung function, respiratory failure, and ultimately death and typically has a poor prognosis, with an average survival time of 2 to 5 years. Related articles suggested that endoplasmic reticulum (ER) stress played a critical role in the occurrence and progression of PF. The ER is responsible for maintaining protein homeostasis. However, factors such as aging, hypoxia, oxidative stress, or inflammation can disrupt this balance, promoting the accumulation of misfolded proteins in the ER and triggering ER stress. To cope with this situation, cells activate the unfolded protein response (UPR). Since acute lung injury (ALI) is one of the key onset events of PF, in this review, we will discuss the role of ER stress in ALI and PF by activating multiple signaling pathways and molecular mechanisms that affect the function and behavior of different cell types, with a focus on epithelial cells, fibroblasts, and macrophages. Linking ER stress to these cell types may broaden our understanding of the mechanisms underlying lung fibrosis and help us target these cells through these mechanisms. The relationship between ER stress and PF is still evolving, and future research will explore new strategies to regulate UPR pathways, providing novel therapeutic targets.

Identifying new molecular signatures and potential therapeutics for idiopathic pulmonary fibrosis: a network medicine approach

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease characterized by excessive collagen deposition and fibrosis of the lung parenchyma, leading to respiratory failure. The molecular mechanisms underlying IPF pathogenesis remain incompletely understood, hindering the development of effective therapeutic strategies. We have used a network medicine approach to comprehensively analyze molecular interactions and identify novel molecular signatures and potential therapeutics associated with IPF progression. Our integrative analysis revealed dysregulated molecular networks that are central to IPF pathophysiology. We have highlighted key molecular players and signaling pathways that are implicated in aberrant fibrotic processes. This systems-level understanding enables the identification of new biomarkers and therapeutic targets for IPF, providing potential avenues for precision medicine. Drug repurposing analysis revealed several drug candidates with anti-fibrotic, anti-inflammatory, and anti-cancer activities that could potentially slow fibrotic progression and improve patient outcomes. This study offers new insights into the molecular underpinnings of IPF and highlights network medicine approaches in uncovering complex disease mechanisms. The molecular signatures and therapeutic targets identified hold promise for developing precision therapies tailored to individual patients, ultimately advancing the management of this debilitating lung disease.

Outcomes and predictors of progression in progressive pulmonary fibrosis

BACKGROUND

Progressive pulmonary fibrosis (PPF) is a general term for a class of interstitial lung diseases (ILDs) characterized by a progressive fibrosing (PF) phenotype. Patients with PPF have decreased lung function, exercise ability, and quality of life. The purpose of this study was to investigate the clinical characteristics, potential associated factors for disease progression, and survival outcomes of patients in the PPF population.

METHODS

This study retrospectively reviewed the data of patients diagnosed with ILD between January 2011 and December 2022 at The First Affiliated Hospital of Ningbo University. A PF phenotype was defined based on the criteria that were used in the PPF clinical practice guidelines, which led to the identification of 92 patients with a PF phenotype among the 177 patients with fibrotic ILD. Baseline clinical information and laboratory parameters were collected and analysed in our cohort.

RESULTS

Patients in the PPF group had higher tumour marker levels and lower pulmonary function test results at baseline than did those in the non-PPF group. According to the multivariate logistic regression analysis, age >65 years (OR 2.71, 95% CI 1.26-5.89; p = 0.011), LDH >245 U/L (OR 3.07, 95% CI 1.39-6.78; p = 0.006), CA-153 > 35 U/mL (OR 3.16, 95% CI 1.25-7.97; p = 0.015), FVC <60% predicted (OR 4.82, 95% CI 1.60-14.51; p = 0.005), DLCO <50% predicted (OR 3.21, 95% CI 1.43-7.21; p = 0.005), and the UIP-like pattern on chest HRCT (OR 3.65, 95% CI 1.33-10.07; p = 0.012) were potentially associated with the progression of fibrotic interstitial lung diseases (f-ILDs) to PPF. Furthermore, the PPF group had a poorer survival rate than the non-PPF group (p = 0.0045). According to the multivariate Cox regression analysis, an SPAP ≥ 37 mmHg (HR 2.33, 95% CI 1.09-5.00; p = 0.030) and acute exacerbation (HR 2.88, 95% CI 1.26-6.59; p = 0.012) were identified as significant prognostic factors for mortality in patients with PPFs.

CONCLUSIONS

Patients who were older, had high CA-153 and LDH levels, had poor pulmonary function test results, or had a UIP-like pattern on chest HRCT were more likely to have indications for the progression of f-ILD to PPF. Increased SPAP and AE are independent risk factors for the prognosis of PPF patients, so additional attention should be given to such patients.

PDE4B inhibition by nerandomilast: Effects on lung fibrosis and transcriptome in fibrotic rats and on biomarkers in human lung epithelial cells

BACKGROUND AND PURPOSE

The PDE4 family is considered a prime target for therapeutic intervention in several fibro-inflammatory diseases. We have investigated the molecular mechanisms of nerandomilast (BI 1015550), a preferential PDE4B inhibitor.

EXPERIMENTAL APPROACH

In addition to clinically relevant parameters of idiopathic pulmonary fibrosis (IPF; lung function measurement/high-resolution computed tomography scan/AI-Ashcroft score), whole-lung homogenates from a therapeutic male Wistar rat model of pulmonary fibrosis were analysed by next-generation sequencing (NGS). Data were matched with public domain data derived from human IPF samples to investigate how well the rat model reflected human IPF. We scored the top counter-regulated genes following treatment with nerandomilast in human single cells and validated disease markers discovered in the rat model using a human disease-relevant in vitro assay of IPF.

KEY RESULTS

Nerandomilast improved the decline of lung function parameters in bleomycin-treated animals. In the NGS study, most transcripts deregulated by bleomycin treatment were normalised by nerandomilast treatment. Most notably, a significant number of deregulated transcripts that were identified in human IPF disease were also found in the animal model and reversed by nerandomilast. Mapping to single-cell data revealed the strongest effects on mesenchymal, epithelial and endothelial cell populations. In a primary human epithelial cell culture system, several disease-related (bio)markers were inhibited by nerandomilast in a concentration-dependent manner.

CONCLUSIONS AND IMPLICATIONS

This study further supports the available knowledge about the anti-inflammatory/antifibrotic mechanisms of nerandomilast and provides novel insights into the mode of action and signalling pathways influenced by nerandomilast treatment of lung fibrosis.

Percent Predicted vs. Absolute Six-Minute Walk Distance as Predictors of Lung Transplant-Free Survival in Fibrosing Interstitial Lung Diseases

INTRODUCTION

Fibrosing interstitial lung diseases (ILDs) often progress despite treatment and become life-threatening, with lung transplant (LTx) remaining the only curative option. Six-minute walk distance (6MWD) is increasingly recognized as reliable predictor of clinical course, especially when longitudinally considered. The use of reference equations to express 6MWD as percent predicted (6MWD%) has not been previously studied in fibrosing ILDs. We sought to investigate whether the prognostic power of 6MWD% is superior to that of 6MWD expressed in meters (6MWD-m).

METHODS

A retrospective, multicenter cohort analysis was conducted on both idiopathic pulmonary (IPF) and non-IPF fibrosing ILD patients. Patients were divided into a discovery (n = 211) and a validation (n = 260) cohort. Longitudinal changes of 6MWD% and lung function parameters were simultaneously considered. LTx-free survival at 3 years from baseline was the endpoint. Competing risks of death and LTx were considered.

RESULTS

Baseline 6MWD% and its longitudinal changes were significant predictors of LTx-free survival and independent from lung function variables. In both cohorts, on multivariate cox proportional hazard regression analysis, receiver operating characteristics analysis and Kaplan-Meier estimates, 6MWD% was consistently, but only slightly superior to 6MWD-m as a predictor of LTx-free survival.

CONCLUSION

6MWD% has only a slight, yet detectable advantage over 6MWD-m as a predictor of survival in fibrosing ILDs. Utilizing 6MWD% may aid in risk stratification, treatment monitoring, and LTx timing optimization. However, available reference equations do have predicting limitations. Refined predictive equations and standardizing reporting practices are therefore needed to further enhance the clinical utility of 6MWD% in fibrosing ILDs.

A Practical Multidisciplinary Approach to Identifying Interstitial Lung Disease in Systemic Autoimmune Rheumatic Diseases: A Clinician's Narrative Review

Interstitial lung disease (ILD) is one of the common and potentially lethal manifestations of systemic autoimmune rheumatic diseases (SARDs). ILD's prevalence, clinical patterns, imaging, and natural history are variable. Each of the representative diseases-systemic sclerosis (SSc), idiopathic inflammatory myopathies (IIMs), rheumatoid arthritis (RA), Sjӧgren's syndrome (SjS), mixed connective tissue disease (MCTD), systemic lupus erythematosus (SLE)-have distinct clinical, paraclinical and evolutionary features. Risk factors with predictive value for ILD have been identified. This review summarizes, from the clinician's perspective, recent data from the literature regarding the specificity of ILD for each of the autoimmune rheumatic diseases, with an emphasis on the role of the multidisciplinary team in early diagnosis, case management, as well as the particularities of the clinical approach to the progressive phenotype of ILD in SARDs.

Drug-Induced Pulmonary Fibrosis: National Database Analysis

BACKGROUND/OBJECTIVES

Pulmonary fibrosis (PF) results in a progressive decline of lung function due to scarring. Drugs are among the most common causes of PF. The objective of our study was to reveal the structure of drugs involved in PF development.

METHODS

we performed a retrospective descriptive pharmacoepidemiologic study on spontaneous reports (SRs) with data on PF registered in the Russian National Pharmacovigilance database for the period from 4 January 2019 to 31 May 2024.

RESULTS

A total of 1308 SRs on PF were finally identified with patients mean age of 59.3 ± 23.4 years. Death was reported in 30.7% (n = 401) with mean age of 59.9 ± 13.8 years. In the structure of culprit drugs, the following groups were leaders: antineoplastic and immunomodulating agents (51.9%); systemic hormonal preparations, excluding sex hormones and insulins (7.4%); drugs affecting nervous system (7.1%); respiratory system (7.1%); alimentary tract and metabolism (6.5%); and cardiovascular system (5.5%). In the total sample, the top ten drugs were rituximab (5.5%), methotrexate (4.4%), etanercept (4.2%), leflunomide (4.0%), adalimumab (3.7%), tocilizumab (3.3%), abatacept (3.0%), alendronic acid (2.7%), secukinumab (2.6%), and infliximab (2.4%). The number of SRs per year nearly doubled from 2021 to 2022 and from 2022 to 2023 with a maximum peak expected for 2024.

CONCLUSIONS

Our study demonstrated increased reporting on PF in the National Pharmacovigilance database from 2019 to 2024. We revealed outstanding results for the role of antineoplastic and immunomodulating agents in PF development.

Serum metalloproteinase-7 as a biomarker of progressive pulmonary fibrosis

Introduction

Progressive pulmonary fibrosis (PPF) corresponds to any fibrotic interstitial lung disease (ILD) other than idiopathic pulmonary fibrosis (IPF) that presents clinical, physiological and/or radiological evidence of disease progression similar to IPF. Matrix metalloproteinases (MMPs) have been implicated in the pathogenesis of pulmonary fibrosis and are associated with disease progression and reduced survival in IPF and other fibrotic ILDs. This study aimed to investigate the role of serum levels of MMP-1 and MMP-7 in patients with fibrotic non-IPF ILD as possible biomarkers of patients at risk of developing PPF.

Methods

Newly diagnosed patients with fibrotic non-IPF ILD were included in this study. Serum levels of MMP-1 and MMP-7 were quantified at baseline and disease progression was monitored. PPF was defined according to the recent European Respiratory Society, American Thoracic Society, Japanese Respiratory Society and the Latin American Thoracic Society Clinical Practice Guidelines.

Results

79 patients with fibrotic non-IPF ILDs were included and classified as having PPF or non-PPF. Significantly higher levels of MMP-7, but not MMP-1, were detected in the PPF group (p=0.01). MMP-7 was independently associated with PPF (adjusted OR 1.263, 95% CI 1.029-1.551; p=0.026) after adjustment for sex, age and smoking history. A cut-off value of 3.53 ng·mL-1 for serum MMP-7 levels had a sensitivity of 61% and a specificity of 74% for predicting PPF in non-IPF ILDs.

Conclusions

In patients with fibrotic non-IPF ILDs, serum MMP-7 levels were significantly greater in the subgroup of patients meeting the PPF criteria at follow-up. This can be considered and further investigated as a possible biomarker to identify fibrotic ILD patients at risk of PPF.

Drug discovery and development in idiopathic pulmonary fibrosis: the changing landscape

Idiopathic pulmonary fibrosis (IPF) is an area of high unmet clinical need and high research activity in the pharmaceutical and biotech industries. The two approved therapies, nintedanib and pirfenidone, have issues with efficacy and tolerability. Despite a considerable number of development programs reaching late-stage Phase 2b or 3 clinical trials, no drug other than nintedanib and pirfenidone has successfully demonstrated a benefit for patients. An analysis of these failures, and consideration of the trajectories of some of the current development projects, may offer novel paradigms for choosing modes-of-action and for the development of successful drugs.

The 1-minute sit-to-stand test to evaluate fibrotic interstitial lung disease

INTRODUCTION

Fibrotic interstitial lung diseases (ILD) are a heterogeneous group of conditions. Progression criteria include clinical, imaging, and/or lung functional decline. Currently, the 6-min walk test (6MWT) is considered the gold standard for assessing exercise-induced desaturation. The 1-min sit-to-stand test (1STST) has the advantage of being easy to perform, making it feasible for use during clinical consultations. The aim of this study was to compare the 1STST with the 6MWT in patients with fibrotic ILD to detect exercise-induced desaturation.

METHODS

A multicenter cross-sectional involved patients with fibrotic ILDs from two centers. The 6MWT and 1STST were performed with a 30-min rest period between the tests. The modified Borg scale was used to assess dyspnea and lower limb fatigue and continuous SpO2 and heart rate were monitored. Desaturation was defined as SpO2 < 90 % or decline >3 %.

RESULTS

Ninety patients were included. The median walking distance in the 6MWT was 432 m and the median number of repetitions in the 1STST was 22, with a significant correlation (p < 0.001, ρ = 0.383). In addition, the minimum SpO2 and the desaturation levels recorded during the tests exhibited a moderate significant correlation (p < 0.001, ρ = 0.502 and p < 0.001, ρ = 0.537, respectively). There was a strong association between the increase in Borg score for dyspnea and a moderate association between the increase in Borg score for lower limb fatigue after both tests (p < 0.001, ρ = 0.706 and p < 0.001, ρ = 0.656, respectively).

CONCLUSIONS

This study demonstrates a significant correlation between the 6MWT and the 1STST in detecting exercise-induced desaturation.

Treatment patterns and patient journey in progressive pulmonary fibrosis: a cross-sectional survey

BACKGROUND

For patients with interstitial lung diseases (ILDs) presenting with a progressive pulmonary fibrosis (PPF) phenotype, current knowledge of disease characteristics at diagnosis, patient journey, and treatment is limited. This study aimed to describe demographics and clinical experiences of patients presenting with PPF in a European real-world setting.

METHODS

Data were analysed from the Adelphi Real World PPF-ILD Disease Specific Programme™, a cross-sectional survey of pulmonologists and rheumatologists in five European countries (France, Germany, Italy, Spain, United Kingdom) and internal medicine specialists (France) from April to October 2022. Physicians provided data for up to 12 consecutive patients with physician-confirmed ILD with a progressive phenotype other than idiopathic pulmonary fibrosis. Analyses were descriptive.

RESULTS

Overall, 265 physicians reported on 1,335 patients. Mean (standard deviation) age at survey date was 60.4 (11.6) years, 91.2% were white, 58.1% female, 44.0% non-smokers. Most patients (63.3%) first consulted a primary care physician. There was a mean delay of 7.8 (22.7) months between first ILD symptom and healthcare professional visit, and another 7.7 (12.8) months to ILD diagnosis. At survey date, 47.7% of patients had physician-reported moderate ILD, 42.3% had mild ILD and 10.0% had severe ILD. Disease progression was reported in the 12 months prior to the survey for 19.5% of patients; of these, progression was based on worsening symptom in 27.3% and lung function decline in 25.8%. For patients experiencing symptoms prior to ILD diagnosis (72.8%), the most common symptoms were dyspnoea on exertion (80.5%) and cough (57.8%). Overall, 17.4% of patients were misdiagnosed prior to ILD diagnosis, with chronic obstructive pulmonary disease suspected in 39.2% of them. The most frequent comorbidities were anxiety (16.9%) and gastroesophageal reflux (15.5%). Although 77.8% of patients were receiving treatment for ILD at survey date, 15.6% of patients had never been prescribed treatment for ILD.

CONCLUSIONS

This real-world study expands our understanding of patients, diagnostic delays and treatment gaps experienced by patients diagnosed with PPF in Europe. There was a mean delay of 15.5 months between first ILD symptoms and ILD diagnosis. Given the progressive nature of PPF, diagnostic delay may lead to poor outcomes, including shorter survival.

TRIAL REGISTRATION

N/a.

Interplay between Lung Diseases and Viral Infections: A Comprehensive Review

The intricate relationship between chronic lung diseases and viral infections is a significant concern in respiratory medicine. We explore how pre-existing lung conditions, including chronic obstructive pulmonary disease, asthma, and interstitial lung diseases, influence susceptibility, severity, and outcomes of viral infections. We also examine how viral infections exacerbate and accelerate the progression of lung disease by disrupting immune responses and triggering inflammatory pathways. By summarizing current evidence, this review highlights the bidirectional nature of these interactions, where underlying lung diseasesincrease vulnerability to viral infections, while these infections, in turn, worsen the clinical course. This review underscores the importance of preventive measures, such as vaccination, early detection, and targeted therapies, to mitigate adverse outcomes in patients with chronic lung conditions. The insights provided aim to inform clinical strategies that can improve patient management and reduce the burden of chronic lung diseases exacerbated by viral infections.

Diagnostic Performance of CLEIA Versus FEIA for KL-6 Peripheral and Alveolar Concentrations in Fibrotic Interstitial Lung Diseases: A Multicentre Study

BACKGROUND

Interstitial lung diseases (ILD) is a group of lung disorders characterized by interstitial lung thickening due to inflammatory and fibrotic processes. Krebs von den Lungen-6 (KL-6) is a molecule secreted by damaged type II alveolar pneumocytes in the alveolar space. The goal of the present study was to compare two detection methods of KL-6 in both bronchoalveolar lavage (BAL) and serum from ILD patients at the moment of diagnosis.

METHODS

Patients with suspicious of ILD and followed at two Italian referral centres for rare lung diseases were included in the study. BAL fluid and serum were collected and analysed by chemiluminescent enzyme immunoassay (CLEIA) and fluorescent enzyme immunoassay (FEIA) methods provided by Tosoh Biosciences.

RESULTS

A total of 158 (mean age ± standard deviation, 61.5 ± 13.7, 65 females) patients were enrolled. A total of, 36 had diagnosis of idiopathic pulmonary fibrosis (IPF), 74 sarcoidosis, 15 connective tissue disease-ILD (CTD-ILD) and 33 other ILD. Diagnostic agreement between two methods was demonstrated for both BAL (r = 0.707, p < 0.0001) and serum (r = 0.816, p < 0.0001). BAL KL-6 values were lower than serum (p < 0.0001). IPF patients had higher serum KL-6 concentration than other ILDs (p = 0.0294), while BAL KL-6 values were lower in IPF than in non-IPF (p = 0.0023).

CONCLUSION

This study explored KL-6 concentrations through the CLEIA method in serum and BAL of patients with various ILDs, showing significant differences of biomarkers concentrations between IPF and other non-IPF ILDs. Our findings are promising as they provided further knowledge concerning KL-6 expression across different ILDs and may suggest its utility in differential diagnosis.

Harmine inhibits pulmonary fibrosis through regulating DNA damage repair-related genes and activation of TP53-Gadd45α pathway

BACKGROUND

Harmine has many pharmacological activities and has been found to significantly inhibit the fibrosis of keloid fibroblasts. DNA damage repair (DDR) is essential to prevent fibrosis. This study aimed to investigate the effects of harmine on pulmonary fibrosis and its underlying mechanisms.

METHODS

Bleomycin and TGF-β1 were used to construct pulmonary fibrosis models in vivo and in vitro, then treated with harmine to explore harmine's effects in treating experimental pulmonary fibrosis and its related mechanisms. Then, RNA sequencing was applied to investigate further the crucial DDR-related genes and drug targets of harmine against pulmonary fibrosis. Finally, the expression levels of DDR-related genes were verified by real-time quantitative PCR (RT-qPCR) and western blot.

RESULTS

Our in vivo experiments showed that harmine treatment could improve weight loss and lung function and reduce tissue fibrosis in mice with pulmonary fibrosis. The results confirmed that harmine could inhibit the viability and migration of TGF-β1-induced MRC-5 cells, induce their apoptosis, and suppress the F-actin expression, suggesting that harmine could suppress the phenotypic transition from lung fibroblasts to lung myoblasts. In addition, RNA sequencing identified 1692 differential expressed genes (DEGs), and 10 DDR-related genes were screened as critical DDR-related genes. RT-qPCR and western blotting showed that harmine could down-regulate the expression of CHEK1, ERCC1, ERCC4, POLD1, RAD51, RPA1, TOP1, and TP53, while up-regulate FEN1, H2AX and GADD45α expression.

CONCLUSIONS

Harmine may inhibit pulmonary fibrosis by regulating DDR-related genes and activating the TP53-Gadd45α pathway.

Evidence from recent clinical trials in fibrotic interstitial lung diseases

PURPOSE OF REVIEW

Idiopathic pulmonary fibrosis (IPF) is the prototype of fibrosing interstitial lung diseases. It is mirrored by progressive pulmonary fibrosis (PPF), an umbrella term which characterizes disease behavior of various fibrotic interstitial lung diseases with irreversible progression, accounting for loss of lung function, exercise intolerance and respiratory failure leading to early mortality. Pirfenidone and nintedanib halve the decline in lung function but do not halt disease progression.

RECENT FINDINGS

Since the publication in 2014 of pivotal pirfenidone and nintedanib studies, a number of clinical trials were conducted, many of them did not reach their primary endpoints. In IPF, promising phase 2 trials were followed by large phase 3 trials that did not confirm a favorable efficacy to tolerability favorable profile, including those with ziritaxestat, an autotaxin-1 inhibitor, zinpentraxin-alpha (human recombinant pentraxin-2), and the monoclonal antibody pamrevlumab targeting connective tissue growth factor. Nevertheless, newer compounds that hold promise are currently being evaluated in phase 3 or phase 2b randomized controlled trials, including: nerandomilast, a preferential phosphodiesterase 4B inhibitor; admilparant, a lysophosphatidic acid receptor antagonist; inhaled treprostinil, a prostacyclin agonist; and bexotegrast, a dual-selective inhibitor of αvβ6 and αvβ1 integrins. Nerandomilast, admilparant, inhaled treprostinil, and inhaled AP01 (pirfenidone), are currently studied in patients with PPF.

SUMMARY

Despite recent frustrating negative results, there is a growing portfolio of candidate drugs developed in both IPF and PPF.

Enhancing Outcomes in Chronic Fibrotic Interstitial Lung Disease Through Aggressive Management of Nintedanib-Induced Adverse Drug Reactions: A Retrospective Analysis

BACKGROUND AND OBJECTIVES

Nintedanib, a tyrosine kinase inhibitor, is integral in slowing pulmonary fibrosis progression in chronic fibrotic interstitial lung disease (ILD). However, the occurrence of adverse drug reactions (ADRs) often limits its use, leading to treatment discontinuation, typically within 3-12 months. Discontinuation adversely affects patient outcomes. The study investigated whether aggressive ADR management can prolong nintedanib therapy and improve patient outcomes.

METHODS

This retrospective, single-center study enrolled Taiwanese patients with chronic fibrotic ILD who were treated with nintedanib from January 2016 to December 2022 in Kaohsiung Chang Gung Memorial Hospital. Patients were categorized into those who discontinued treatment within 180 days and those continuing beyond. Management of ADRs was identified through concurrent prescriptions for symptoms such as nausea, vomiting, diarrhea, or hepatic dysfunction. Baseline demographics, comorbidities, pulmonary function tests, and instances of acute exacerbation were analyzed.

RESULTS

The study enrolled 94 patients, with 71 (75.5%) experiencing ADRs. Among these, 41 (43.6%) discontinued nintedanib within 180 days. The administration of medications for managing nausea/vomiting [17 (41.5%) versus 36 (67.9%), p = 0.0103] and diarrhea [12 (29.3%) versus 33 (62.3%), p = 0.0015] was less frequent in the discontinued group compared with the continued group. Additionally, a higher incidence of acute exacerbation was observed in the discontinued group (34.1% versus 20.8%, p = 0.016).

CONCLUSION

Aggressive management of ADRs may enhance patient tolerance to nintedanib, potentially prolonging treatment duration and improving outcomes in chronic fibrotic ILD.

The burden of cough in idiopathic pulmonary fibrosis and other interstitial lung diseases: a systematic evidence synthesis

BACKGROUND

Cough remains a persistent symptom in patients with idiopathic pulmonary fibrosis (IPF) and other interstitial lung diseases (ILDs). To inform future research, treatment and care models, we conducted the first systematic synthesis of evidence on its associated burden.

METHODS

A literature search was performed for articles published between January 2010 and October 2023 using databases including Embase, MEDLINE and the Cochrane Library. Studies in patients with IPF and other ILDs reporting cough-related measures were eligible for inclusion. Included studies were categorised based on the types of ILD they examined and their design. Study details, patient characteristics and outcomes were extracted, and the risk of bias was assessed. A narrative synthesis approach was employed to interpret the findings.

RESULTS

Sixty-one studies were included: 33 in IPF, 18 in mixed-ILDs, six in connective tissue disease-associated-ILDs and four in sarcoidosis. Across the studies, a range of tools to assess cough and its impact were used. The most frequently used measures of cough were cough severity visual analogue scale (VAS) and objective cough counts, whereas the most frequently used health-related quality of life (HRQoL)/impact measures were the St. George's Respiratory Questionnaire (SGRQ) and Leicester Cough Questionnaire (LCQ). In IPF, studies consistently reported correlations between various cough and HRQoL measures, including between cough VAS scores and objective cough counts, LCQ scores and SGRQ scores. Similar correlations were observed in studies in other ILDs, but data were more limited. Qualitative studies in both IPF and other ILDs consistently highlighted the significant cough-related burden experienced by patients, including disruption of daily activities, fatigue and social embarrassment. Although there were no studies specifically investigating the economic burden of cough, one study in patients with fibrotic ILD found cough severity was associated with workplace productivity loss.

CONCLUSIONS

Our study underscores the heterogeneity in assessing cough and its impact in IPF and other ILDs. The findings confirm the negative impact of cough on HRQoL in IPF and suggest a comparable impact in other ILDs. Our synthesis highlights the need for standardised assessment tools, along with dedicated studies, particularly in non-IPF ILDs and on the economic burden of cough.

Establishment of a stem cell administration imaging method in bleomycin-induced pulmonary fibrosis mouse models

Pulmonary fibrosis is a progressive disease caused by interstitial inflammation. Treatments are extremely scarce; therapeutic drugs and transplantation therapies are not widely available due to cost and a lack of donors, respectively. Recently, there has been a high interest in regenerative medicine and exponential advancements in stem cell-based therapies have occurred. However, a sensitive imaging technique for investigating the in vivo dynamics of transplanted stem cells has not yet been established and the mechanisms of stem cell-based therapy remain largely unexplored. In this study, we administered mouse adipose tissue-derived mesenchymal stem cells (mASCs) labeled with quantum dots (QDs; 8.0 nM) to a mouse model of bleomycin-induced pulmonary fibrosis in an effort to clarify the relationship between in vivo dynamics and therapeutic efficacy. These QD-labeled mASCs were injected into the trachea of C57BL/6 mice seven days after bleomycin administration to induce fibrosis in the lungs. The therapeutic effects and efficacy were evaluated via in vivo/ex vivo imaging, CT imaging, and H&E staining of lung sections. The QD-labeled mASCs remained in the lungs longer and suppressed fibrosis. The 3D imaging results showed that the transplanted cells accumulated in the peripheral and fibrotic regions of the lungs. These results indicate that mASCs may prevent fibrosis. Thus, QD labeling could be a suitable and sensitive imaging technique for evaluating in vivo kinetics in correlation with the efficacy of cell therapy.

A quantitative analysis of progressive fibrosing interstitial lung disease on computed tomography for the assessment of decreased vital capacity

BACKGROUND

The results of a quantitative analysis of computed tomography (CT) of interstitial lung disease (ILD) using a computer-aided detection (CAD) technique were correlated with the results of pulmonary function tests.

PURPOSE

To evaluate the correlation between a quantitative analysis of CT of progressive fibrosing interstitial lung disease (PF-ILD) including idiopathic pulmonary fibrosis (IPF) and non-IPF, which can manifest progressive pulmonary fibrosis and the vital capacity (VC), and to identify indicators for the assessment of a decreased VC.

MATERIAL AND METHODS

A total of 73 patients (46 patients with IPF and 27 patients with non-IPF) were included in this study. Associations between the quantitative analysis of CT and the %VC using a CAD software program were investigated using Spearman's rank correlation and a logistic regression analysis. The appropriate cutoff vale for predicting a decreased VC was determined (%VC <80) and the area under the curve (AUC) was calculated.

RESULTS

A multiple logistic regression analysis showed that the total extent of interstitial pneumonia on CT was a significant indicator of a decreased VC (P = 0.0001; odds ratio [OR]=1.15; 95% confidence interval [CI]=1.06-1.27 in IPF and P = 0.0025; OR=1.16; 95% CI=1.03-1.30 in non-IPF). The cutoff values of the total extent of interstitial pneumonia in IPF and non-IPF for predicting a decreased VC were determined to be 23.3% and 21.5%, and the AUCs were 0.83 and 0.91, respectively.

CONCLUSION

A quantitative analysis of CT of PF-ILD using a CAD software program could be useful for predicting a decreased VC.

Clinically Relevant Biomarkers in Connective Tissue Disease-Associated Interstitial Lung Disease

Interstitial lung disease (ILD) complicates connective tissue disease (CTD) with variable incidence and is a leading cause of death in these patients. To improve CTD-ILD outcomes, early recognition and management of ILD is critical. Blood-based and radiologic biomarkers that assist in the diagnosis CTD-ILD have long been studied. Recent studies, including -omic investigations, have also begun to identify biomarkers that may help prognosticate such patients. This review provides an overview of clinically relevant biomarkers in patients with CTD-ILD, highlighting recent advances to assist in the diagnosis and prognostication of CTD-ILD.

Serum stratifin measurement is useful for evaluating disease severity and outcomes in patients with acute exacerbation of interstitial lung disease: a retrospective study

BACKGROUND

Serum levels of stratifin (SFN), a member of the 14-3-3 protein family, increase in patients with drug-induced lung injury associated with diffuse alveolar damage. Therefore, we hypothesised that SFN levels would be higher in those experiencing acute exacerbation of interstitial lung disease (AE-ILD). A secondary analysis was also planned to determine whether SFN levels could discriminate survival in those with AE.

METHODS

Thirty-two patients with clinically stable ILD (CS-ILD) and 22 patients with AE-ILD were examined to assess whether high serum SFN levels were associated with AE-ILD and whether SFN levels reflected disease severity or prognosis in patients with AE-ILD.

RESULTS

Serum SFN levels were higher in the AE-ILD group than in the CS-ILD group (8.4 ± 7.6 vs. 1.3 ± 1.2 ng/mL, p < 0.001). The cut-off value of the serum SFN concentration for predicting 90-day and 1-year survival was 6.6 ng/mL. SFN levels were higher in patients who died within 90 days and 1 year than in patients who survived beyond these time points (13.5 ± 8.7 vs. 5.6 ± 5.3 ng/mL; p = 0.011 and 13.1 ± 7.5 vs. 3.1 ± 1.9 ng/mL; p < 0.001, respectively) in the AE-ILD group. When this cut-off value was used, the 90-day and 1-year survival rates were significantly better in the population below the cut-off value than in those above the cut-off value (p = 0.0017 vs. p < 0.0001).

CONCLUSIONS

High serum SFN levels are associated with AE-ILD and can discriminate survival in patients with AE-ILD.

Progressive pulmonary fibrosis (PPF): Estimation of incidence and treatment rates in Japan using a claims database

BACKGROUND

Interstitial lung diseases (ILDs) are a heterogeneous group of disorders, a subset of which develop progressive pulmonary fibrosis (PPF). There is little information on the epidemiology and treatment of PPFs in Japan. This retrospective cohort study estimated the incidence probability of progression to PPFs in patients with fibrosing ILDs other than idiopathic pulmonary fibrosis in a real-world Japanese setting. Management procedures and treatment patterns were also quantified.

METHODS

Data were extracted from the Medical Data Vision database from 01-Jan-2012 to 28-May-2020, comprising a 6.91-year patient identification period, 1-year pre-index period, and post-index period. The primary outcome was the cumulative incidence probability of progression to PPF up to 24 months. Subgroup analyses were performed by the presence/absence of connective tissue disease-ILD and by pre-specified ILD clinical diagnosis.

RESULTS

Of the 34,960 eligible patients (mean age: 71.1 years, males: 52.5%), 14,580 (41.7%) progressed to PPF. The 24-month incidence probability of progression to PPF was 39.5%. A relatively comparable percentage of patients progressed across all ILD subtypes. Oral corticosteroids and tacrolimus were the most common therapies during the pre- and post-index periods. Treatment rates were very low in the post-index period.

CONCLUSIONS

This is the first claims database study to estimate the incidence probability of progression to PPF in Japan. Progression appeared common in patients with chronic fibrosing ILDs, with comparable percentages of patients across all subtypes developing PPF at 2 years. Future studies should assess the impact of regular monitoring and early intervention on treating fibrotic ILDs and preventing progression.

The current landscape of antifibrotic therapy across different organs: A systematic approach

Fibrosis is a common pathological process that can affect virtually all the organs, but there are hardly any effective therapeutic options. This has led to an intense search for antifibrotic therapies over the last decades, with a great number of clinical assays currently underway. We have systematically reviewed all current and recently finished clinical trials involved in the development of new antifibrotic drugs, and the preclinical studies analyzing the relevance of each of these pharmacological strategies in fibrotic processes affecting tissues beyond those being clinically studied. We analyze and discuss this information with the aim of determining the most promising options and the feasibility of extending their therapeutic value as antifibrotic agents to other fibrotic conditions.

Mechanisms and consequences of excess exercise ventilation in fibrosing interstitial lung disease

The causes and consequences of excess exercise ventilation (EEV) in patients with fibrosing interstitial lung disease (f-ILD) were explored. Twenty-eight adults with f-ILD and 13 controls performed an incremental cardiopulmonary exercise test. EEV was defined as ventilation-carbon dioxide output (⩒E-⩒CO2) slope ≥36 L/L. Patients showed lower pulmonary function and exercise capacity compared to controls. Lower DLCO was related to higher ⩒E-⩒CO2 slope in patients (P<0.05). 13/28 patients (46.4%) showed EEV, reporting higher dyspnea scores (P=0.033). Patients with EEV showed a higher dead space (VD)/tidal volume (VT) ratio while O2 saturation dropped to a greater extent during exercise compared to those without EEV. Higher breathing frequency and VT/inspiratory capacity ratio were observed during exercise in the former group (P<0.05). An exaggerated ventilatory response to exercise in patients with f-ILD is associated with a blunted decrease in the wasted ventilation in the physiological dead space and greater hypoxemia, prompting higher inspiratory constraints and breathlessness.

Prognostic significance of body mass index and weight loss in patients with idiopathic pleuroparenchymal fibroelastosis

BACKGROUND AND AIM

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare form of idiopathic interstitial pneumonias; its physical characteristics include a slender build with platythorax and progressive weight loss. However, the clinical significance of body mass index (BMI) and weight loss remains unclear in patients with IPPFE. Therefore, we aimed to clarify the association between baseline BMI, weight loss after diagnosis, and the prognosis of patients with IPPFE.

METHODS

This retrospective study included 71 patients diagnosed with IPPFE at our institution between 2005-2021. BMI at diagnosis was classified into three: underweight (<18.5 kg/m2), normal weight (≥18.5 to <25.0 kg/m2), or overweight (≥25.0 kg/m2). An annual rate of weight change after the diagnosis was evaluated, and ≥5% per year decrease was defined as a significant weight loss. We investigated clinical features and prognosis based on baseline BMI and weight loss.

RESULTS

Of the 71 patients, 48 (67.6%) and 23 (32.4%) were classified as underweight and normal weight, respectively, and none were overweight. Significant weight loss occurred in 24 (33.8%) patients, and they tended to have more cases of dyspnea and had significantly older age, lower BMI, higher rates of co-existence of lower-lobe interstitial lung disease, lower pulmonary function test results and higher incidence of pneumothorax after the diagnosis than those without weight loss. Patients with BMI <18.5 kg/m2 and those with weight loss had a significantly worse prognosis than those with BMI ≥18.5 kg/m2 or those without weight loss, respectively (p=0.005, p<0.001). Multivariate analysis revealed that low BMI and weight loss were independent poor prognostic factors.

CONCLUSIONS

Low BMI and weight loss are associated with poor prognosis in patients with IPPFE.

Genomic Profiling for Predictive Treatment Strategies in Fibrotic Interstitial Lung Disease

Idiopathic pulmonary fibrosis (IPF) has traditionally been considered the archetype of progressive fibrotic interstitial lung diseases (f-ILDs), but several other f-ILDs can also manifest a progressive phenotype. Integrating genomic signatures into clinical practice for f-ILD patients may help to identify patients predisposed to a progressive phenotype. In addition to the risk of progressive pulmonary fibrosis, there is a growing body of literature examining how pharmacogenomics influences treatment response, particularly regarding the efficacy and safety profiles of antifibrotic and immunomodulatory agents. In this narrative review, we discuss current studies in IPF and other forms of pulmonary fibrosis, including systemic autoimmune disorders associated ILDs, sarcoidosis and hypersensitivity pneumonitis. We also provide insights into the future direction of research in this complex field.

SFTPB in serum extracellular vesicles as a biomarker of progressive pulmonary fibrosis

Progressive pulmonary fibrosis (PPF), defined as the worsening of various interstitial lung diseases (ILDs), currently lacks useful biomarkers. To identify novel biomarkers for early detection of patients at risk of PPF, we performed a proteomic analysis of serum extracellular vesicles (EVs). Notably, the identified candidate biomarkers were enriched for lung-derived proteins participating in fibrosis-related pathways. Among them, pulmonary surfactant-associated protein B (SFTPB) in serum EVs could predict ILD progression better than the known biomarkers, serum KL-6 and SP-D, and it was identified as an independent prognostic factor from ILD-gender-age-physiology index. Subsequently, the utility of SFTPB for predicting ILD progression was evaluated further in 2 cohorts using serum EVs and serum, respectively, suggesting that SFTPB in serum EVs but not in serum was helpful. Among SFTPB forms, pro-SFTPB levels were increased in both serum EVs and lungs of patients with PPF compared with those of the control. Consistently, in a mouse model, the levels of pro-SFTPB, primarily originating from alveolar epithelial type 2 cells, were increased similarly in serum EVs and lungs, reflecting pro-fibrotic changes in the lungs, as supported by single-cell RNA sequencing. SFTPB, especially its pro-form, in serum EVs could serve as a biomarker for predicting ILD progression.

Antifibrotic therapy in progressive pulmonary fibrosis: a review of recent advances

INTRODUCTION

Progressive pulmonary fibrosis (PPF) is a manifestation of a heterogenous group of underlying interstitial lung disease (ILD) diagnoses, defined as non-idiopathic pulmonary fibrosis (IPF) progressive fibrotic ILD meeting at least two of the following criteria in the previous 12 months: worsening respiratory symptoms, absolute decline in forced vital capacity (FVC) more than or equal to 5% and/or absolute decline in diffusing capacity for carbon monoxide (DLCO) more than or equal to 10% and/or radiological progression.

AREAS COVERED

The authors subjectively reviewed a synthesis of literature from PubMed to identify recent advances in the diagnosis and characterisation of PPF, treatment recommendations, and management challenges. This review provides a comprehensive summary of recent advances and highlights future directions for the diagnosis, management, and treatment of PPF.

EXPERT OPINION

Recent advances in defining the criteria for PPF diagnosis and licensing of treatment are likely to support further characterisation of the PPF patient population and improve our understanding of prevalence. The diagnosis of PPF remains challenging with the need for a specialised ILD multidisciplinary team (MDT) approach. The evidence base supports the use of immunomodulatory therapy to treat inflammatory ILDs and antifibrotic therapy where PPF develops. Treatment needs to be tailored to the specific underlying disease and determined on a case-by-case basis.

U-net convolutional neural network applied to progressive fibrotic interstitial lung disease: Is progression at CT scan associated with a clinical outcome?

BACKGROUND

Computational advances in artificial intelligence have led to the recent emergence of U-Net convolutional neural networks (CNNs) applied to medical imaging. Our objectives were to assess the progression of fibrotic interstitial lung disease (ILD) using routine CT scans processed by a U-Net CNN developed by our research team, and to identify a progression threshold indicative of poor prognosis.

METHODS

CT scans and clinical history of 32 patients with idiopathic fibrotic ILDs were retrospectively reviewed. Successive CT scans were processed by the U-Net CNN and ILD quantification was obtained. Correlation between ILD and FVC changes was assessed. ROC curve was used to define a threshold of ILD progression rate (PR) to predict poor prognostic (mortality or lung transplantation). The PR threshold was used to compare the cohort survival with Kaplan Mayer curves and log-rank test.

RESULTS

The follow-up was 3.8 ± 1.5 years encompassing 105 CT scans, with 3.3 ± 1.1 CT scans per patient. A significant correlation between ILD and FVC changes was obtained (p = 0.004, ρ = -0.30 [95% CI: -0.16 to -0.45]). Sixteen patients (50%) experienced unfavorable outcome including 13 deaths and 3 lung transplantations. ROC curve analysis showed an aera under curve of 0.83 (p < 0.001), with an optimal cut-off PR value of 4%/year. Patients exhibiting a PR ≥ 4%/year during the first two years had a poorer prognosis (p = 0.001).

CONCLUSIONS

Applying a U-Net CNN to routine CT scan allowed identifying patients with a rapid progression and unfavorable outcome.

A study on the prevalence and prognosis of progressive pulmonary fibrosis: A retrospective observational study

Interstitial lung disease (ILD) encompasses a heterogeneous group of more than 200 diffuse parenchymal lung diseases with various clinical courses. Disease progression is one of the most important prognostic factors, and, the definition of progressive pulmonary fibrosis (PPF) has recently been established. This study aimed to estimate the prevalence, risk factors, and prognosis of PPF among patients with non-idiopathic pulmonary fibrosis (IPF) in real-world practice. A total of 215 patients were retrospectively analyzed between January 2010 and June 2023 at the Haeundae Paik Hospital in the Republic of Korea. According to the criteria proposed in 2022 by Raghu et al, PPF defined as a condition that satisfies 2 or more of the following in the past year: worsening of respiratory symptoms, physiological evidence of disease progression, and radiological evidence of disease progression. The median age of the subjects was 67 years and 63.7% were female. A total of 40% was diagnosed with PPF and connective tissue disease-associated ILD (52.3%) was the most common type, followed by nonspecific interstitial pneumonitis (NSIP) (25.6%) and cryptogenic organizing pneumonitis (16.3%). In multivariate logistic regression for predicting PPF, both the use of steroids and immunosuppressants (OR: 2.57, 95% CI: 1.41-4.67, P = .002) and home oxygen use (OR: 25.17, 95% CI: 3.21-197.24, P = .002) were independent risk factors. During the follow-up period, the mortality rate was significantly higher in the PPF group than in the non-PPF group (24.4% vs 2.3%, P < .001). In the survival analysis using the Cox proportional hazard regression model, disease progression, older age and lower forced vital capacity (FVC) were independent risk factors for mortality. Our study demonstrated that the prevalence of PPF was 40%. Concomitant therapy of steroids with an immunosuppressants and home oxygen use are risk factors for PPF. PPF itself was significantly associated with high mortality rates. Risk factors for mortality were disease progression, older age, and lower FVC.

Interstitial lung disease: a review of classification, etiology, epidemiology, clinical diagnosis, pharmacological and non-pharmacological treatment

Interstitial lung diseases (ILDs) refer to a heterogeneous and complex group of conditions characterized by inflammation, fibrosis, or both, in the interstitium of the lungs. This results in impaired gas exchange, leading to a worsening of respiratory symptoms and a decline in lung function. While the etiology of some ILDs is unclear, most cases can be traced back to factors such as genetic predispositions, environmental exposures (including allergens, toxins, and air pollution), underlying autoimmune diseases, or the use of certain medications. There has been an increase in research and evidence aimed at identifying etiology, understanding epidemiology, improving clinical diagnosis, and developing both pharmacological and non-pharmacological treatments. This review provides a comprehensive overview of the current state of knowledge in the field of interstitial lung diseases.