Fibrosing interstitial lung diseases: knowns and unknowns

Bletilla striata polysaccharide attenuated the progression of pulmonary fibrosis by inhibiting TGF-β1/Smad signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Bletilla striata, a traditional medicinal plant, has been utilized as a folk medicine for many years because of its superior biological activity in China. However, Bletilla striata polysaccharide (BSP) has received less attention, and its specific mechanism for ameliorating pulmonary fibrosis is completely unclear.

AIMS OF THE STUDY

In this study, we aim to assess BSP on the treatment of PF and explore potential mechanisms.

MATERIALS AND METHODS

BSP was successfully extracted and purified from Bletilla striata. The mechanisms were assessed in bleomycin-induced pulmonary fibrosis model and lung fibroblasts activated by transforming growth factor-β1 (TGF-β1). Histological analysis, immunofluorescence, Western blot and flow cytometry were used to explore the alterations after BSP intervention.

RESULTS

The results in vivo showed an anti-PF effect of BSP treatment, which reduced pathogenic damages. Furthermore, TGF-β1-induced abnormal migration and upregulated expression of collagen I (COL1A1), vimentin and α-smooth muscle actin (α-SMA) were suppressed by BSP in L929 cells. Moreover, the abnormal proliferation was retarded by inhibiting the cell cycle of G1 to S phase. Immunofluorescence assay showed that BSP activated autophagy and played an antifibrotic role by inhibiting the expression of p62 and phospho-mammalian target of rapamycin (p-mTOR). Last but not least, the suppression of TGF-β1/Smad signaling pathway was critical for BSP to perform therapeutic effects in vitro and in vivo.

CONCLUSION

The possible mechanisms were involved in improving ECM deposition, regulating cell migration and proliferation, and promoting cellular autophagy. Briefly, all of the above revealed that BSP might be a novel therapy for treating pulmonary fibrosis.

Caffeic acid ethanolamide induces antifibrosis, anti-inflammatory, and antioxidant effects protects against bleomycin-induced pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive interstitial lung disease; its cause is unknown, and it leads to notable health problems. Currently, only two drugs are recommended for IPF treatment. Although these drugs can mitigate lung function decline, neither can improve nor stabilize IPF or the symptoms perceived by patients. Therefore, the development of novel treatment options for pulmonary fibrosis is required. The present study investigated the effects of a novel compound, caffeic acid ethanolamide (CAEA), on human pulmonary fibroblasts and evaluated its potential to mitigate bleomycin-induced pulmonary fibrosis in mice. CAEA inhibited TGF-β-induced α-SMA and collagen expression in human pulmonary fibroblasts, indicating that CAEA prevents fibroblasts from differentiating into myofibroblasts following TGF-β exposure. In animal studies, CAEA treatment efficiently suppressed immune cell infiltration and the elevation of TNF-α and IL-6 in bronchoalveolar lavage fluid in mice with bleomycin-induced pulmonary fibrosis. Additionally, CAEA exerted antioxidant effects by recovering the enzymatic activities of oxidant scavengers. CAEA directly inhibited activation of TGF-β receptors and protected against bleomycin-induced pulmonary fibrosis through inhibition of the TGF-β/SMAD/CTGF signaling pathway. The protective effect of CAEA was comparable to that of pirfenidone, a clinically available drug. Our findings support the potential of CAEA as a viable method for preventing the progression of pulmonary fibrosis.

Mitochondrial network dynamics in pulmonary disease: Bridging the gap between inflammation, oxidative stress, and bioenergetics

Once thought of in terms of bioenergetics, mitochondria are now widely accepted as both the orchestrator of cellular health and the gatekeeper of cell death. The pulmonary disease field has performed extensive efforts to explore the role of mitochondria in regulating inflammation, cellular metabolism, apoptosis, and oxidative stress. However, a critical component of these processes needs to be more studied: mitochondrial network dynamics. Mitochondria morphologically change in response to their environment to regulate these processes through fusion, fission, and mitophagy. This allows mitochondria to adapt their function to respond to cellular requirements, a critical component in maintaining cellular homeostasis. For that reason, mitochondrial network dynamics can be considered a bridge that brings multiple cellular processes together, revealing a potential pathway for therapeutic intervention. In this review, we discuss the critical modulators of mitochondrial dynamics and how they are affected in pulmonary diseases, including chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), acute lung injury (ALI), and pulmonary arterial hypertension (PAH). A dysregulated mitochondrial network plays a crucial role in lung disease pathobiology, and aberrant fission/fusion/mitophagy pathways are druggable processes that warrant further exploration. Thus, we also discuss the candidates for lung disease therapeutics that regulate mitochondrial network dynamics.

Mycophenolate and azathioprine efficacy in interstitial lung disease: a systematic review and meta-analysis

OBJECTIVES

Mycophenolate mofetil (MMF) and azathioprine (AZA) are immunomodulatory treatments in interstitial lung disease (ILD). This systematic review aimed to evaluate the efficacy of MMF or AZA on pulmonary function in ILD.

DESIGN

Population included any ILD diagnosis, intervention included MMF or AZA treatment, outcome was delta change from baseline in per cent predicted forced vital capacity (%FVC) and gas transfer (diffusion lung capacity of carbon monoxide, %DLco). The primary endpoint compared outcomes relative to placebo comparator, the secondary endpoint assessed outcomes in treated groups only.

ELIGIBILITY CRITERIA

Randomised controlled trials (RCTs) and prospective observational studies were included. No language restrictions were applied. Retrospective studies and studies with high-dose concomitant steroids were excluded.

DATA SYNTHESIS

The systematic search was performed on 9 May. Meta-analyses according to drug and outcome were specified with random effects, I2 evaluated heterogeneity and Grading of Recommendations, Assessment, Development and Evaluation evaluated certainty of evidence. Primary endpoint analysis was restricted to RCT design, secondary endpoint included subgroup analysis according to prospective observational or RCT design.

RESULTS

A total of 2831 publications were screened, 12 were suitable for quantitative synthesis. Three MMF RCTs were included with no significant effect on the primary endpoints (%FVC 2.94, 95% CI -4.00 to 9.88, I2=79.3%; %DLco -2.03, 95% CI -4.38 to 0.32, I2=0.0%). An overall 2.03% change from baseline in %FVC (95% CI 0.65 to 3.42, I2=0.0%) was observed in MMF, and RCT subgroup summary estimated a 4.42% change from baseline in %DLCO (95% CI 2.05 to 6.79, I2=0.0%). AZA studies were limited. All estimates were considered very low certainty evidence.

CONCLUSIONS

There were limited RCTs of MMF or AZA and their benefit in ILD was of very low certainty. MMF may support preservation of pulmonary function, yet confidence in the effect was weak. To support high certainty evidence, RCTs should be designed to directly assess MMF efficacy in ILD.

PROSPERO REGISTRATION NUMBER

CRD42023423223.

Health care costs and utilization of progressive fibrosing lung disease by underlying interstitial lung disease type

BACKGROUND

Fibrosing interstitial lung disease (ILD) encompasses more than 200 diverse pulmonary disorders, of which up to 40% become progressive. The 4 underlying ILD types most likely to result in progression are unclassified ILD/idiopathic interstitial pneumonia (IIP), autoimmune ILDs, exposure-related ILD/hypersensitivity pneumonitis, and sarcoidosis.

OBJECTIVE

To compare health care resource utilization (HCRU) and costs among patients with fibrosing ILD that has progressed ("progressive" fibrosing cohort) vs patients whose fibrosis did not meet criteria set for progression ("not yet progressed" cohort).

METHODS

This was a noninterventional study of commercial enrollees and Medicare Advantage with Part D beneficiaries, which used administrative claims data for the period from October 1, 2015, through May 31, 2021. Adult patients (aged ≥18 years) with fibrosing ILD and 12 months of continuous health plan enrollment were included. Patients with idiopathic pulmonary fibrosis, baseline ILD diagnoses, or missing demographic data were excluded. Patients were first classified according to the underlying type of fibrosing ILD. For statistical analyses of outcomes, 2 cohorts were compared within each subtype: progressive fibrosing ILD vs not yet progressed ILD. The final study population included propensity score-matched (PSM) patients (1:1) based on pre-ILD baseline demographic and clinical characteristics. HCRU categories included inpatient hospitalization counts and the number of inpatient days and total costs (in 2021 US dollars), analyzed descriptively and weighted by the per-patient-per-month cost. Lin's regression was used to predict 12-month total cost estimates for comparison by cohort.

RESULTS

The distribution by underlying conditions was as follows: autoimmune ILD (n = 4,156), HP (n = 8,181), sarcoidosis (n = 775), and unclassified ILD/IIP (n = 18,635). After PSM, pre-ILD baseline variables were generally well balanced between the progressive and not yet progressed fibrosing ILD cohorts. For all underlying subtypes of ILD, patients in the progressive cohort had significantly more utilization and higher costs compared with patients in the not yet progressed cohort. Progressive cohorts had significantly higher adjusted rates of inpatient days among patients with at least 1 inpatient stay compared with the not yet progressed cohorts (all P < 0.01). In addition, the progressive cohorts had significantly higher adjusted 12-month total costs, with the differences ranging from $24,493 to $55,072 (all comparisons P < 0.001).

CONCLUSIONS

Irrespective of underlying ILD type, patients with progressive fibrosing ILD had significantly increased HCRU and cost relative to those whose fibrosing ILD had not yet progressed.

Treatment of idiopathic pulmonary fibrosis and progressive pulmonary fibrosis: A position statement from the Thoracic Society of Australia and New Zealand 2023 revision

Idiopathic pulmonary fibrosis (IPF) is a progressive disease leading to significant morbidity and mortality. In 2017 the Thoracic Society of Australia and New Zealand (TSANZ) and Lung Foundation Australia (LFA) published a position statement on the treatment of IPF. Since that time, subsidized anti-fibrotic therapy in the form of pirfenidone and nintedanib is now available in both Australia and New Zealand. More recently, evidence has been published in support of nintedanib for non-IPF progressive pulmonary fibrosis (PPF). Additionally, there have been numerous publications relating to the non-pharmacologic management of IPF and PPF. This 2023 update to the position statement for treatment of IPF summarizes developments since 2017 and reaffirms the importance of a multi-faceted approach to the management of IPF and progressive pulmonary fibrosis.

Alveolar Organoids in Lung Disease Modeling

Lung organoids display a tissue-specific functional phenomenon and mimic the features of the original organ. They can reflect the properties of the cells, such as morphology, polarity, proliferation rate, gene expression, and genomic profile. Alveolar type 2 (AT2) cells have a stem cell potential in the adult lung. They produce and secrete pulmonary surfactant and proliferate to restore the epithelium after damage. Therefore, AT2 cells are used to generate alveolar organoids and can recapitulate distal lung structures. Also, AT2 cells in human-induced pluripotent stem cell (iPSC)-derived alveolospheres express surfactant proteins and other factors, indicating their application as suitable models for studying cell-cell interactions. Recently, they have been utilized to define mechanisms of disease development, such as COVID-19, lung cancer, idiopathic pulmonary fibrosis, and chronic obstructive pulmonary disease. In this review, we show lung organoid applications in various pulmonary diseases, drug screening, and personalized medicine. In addition, stem cell-based therapeutics and approaches relevant to lung repair were highlighted. We also described the signaling pathways and epigenetic regulation of lung regeneration. It is critical to identify novel regulators of alveolar organoid generations to promote lung repair in pulmonary diseases.

Interstitial lung disease hospitalizations, outcomes, and costs in the United States from 2008 to 2018

BACKGROUND

Interstitial lung diseases (ILD) are associated with frequent hospitalizations, however, limited studies have evaluated the hospitalization rates and outcomes.

STUDY DESIGN AND METHODS

We extracted hospitalization data for ILD patients using the National Inpatient Sample Database. Regression models were used to assess trends in hospitalizations and outcomes.

RESULTS

There were 345,063 hospitalizations with a principal diagnosis of ILD from 2008 to 2018. Hospitalization rates were higher in females, older age groups, and those living in rural areas. Rates were lower in those with income levels at or above the median and in the western U.S. Of those hospitalized, 5.1 % died, and ∼37 % required skilled nursing facility/home health. Deaths were lower among females and in those with Medicaid and private insurance. Rates were higher in the older age groups, those with median and above income levels, and those living in medium/small metro and rural areas. The overall hospitalization rate decreased by ∼23 % during this period. The percentage of deaths remained stable (except in rural hospitals) during this period. The average length of stay (LOS) was 5.5 days. The average hospital cost was $10,438 which increased by ∼38 %.

INTERPRETATION

Hospitalizations for ILD have been decreasing, however, the death percentage has been stable. The LOS has remained stable, but hospital costs have been increasing. We identified differences in ILD hospitalization rates and outcomes/costs based on patient and hospital characteristics. Identifying the causes for these differences would be important in reducing health disparities in ILD patients.

CLINICAL TRIAL REGISTRATION

n/a.

Diagnosis of interstitial lung diseases: from Averill A. Liebow to artificial intelligence

Histopathologic criteria of usual interstitial pneumonia (UIP)/idiopathic pulmonary fibrosis (IPF) were defined over the years and endorsed by leading organizations decades after Dr. Averill A. Liebow first coined the term UIP in the 1960s as a distinct pathologic pattern of fibrotic interstitial lung disease. Novel technology and recent research on interstitial lung diseases with genetic component shed light on molecular pathogenesis of UIP/IPF. Two antifibrotic agents introduced in the mid-2010s opened a new era of therapeutic approaches to UIP/IPF, albeit contentious issues regarding their efficacy, side effects, and costs. Recently, the concept of progressive pulmonary fibrosis was introduced to acknowledge additional types of progressive fibrosing interstitial lung diseases with the clinical and pathologic phenotypes comparable to those of UIP/IPF. Likewise, some authors have proposed a paradigm shift by considering UIP as a stand-alone diagnostic entity to encompass other fibrosing interstitial lung diseases that manifest a relentless progression as in IPF. These trends signal a pendulum moving toward the tendency of lumping diagnoses, which poses a risk of obscuring potentially important information crucial to both clinical and research purposes. Recent advances in whole slide imaging for digital pathology and artificial intelligence technology could offer an unprecedented opportunity to enhance histopathologic evaluation of interstitial lung diseases. However, current clinical practice trends of moving away from surgical lung biopsies in interstitial lung disease patients may become a limiting factor in this endeavor as it would be difficult to build a large histopathologic database with correlative clinical data required for artificial intelligence models.

The phenotype of mixed connective tissue disease patients having associated interstitial lung disease

OBJECTIVE

We aimed to compare two matched populations of patients with MTCD with and without associated ILD and to identify predictive factors for ILD progression and severity.

METHODS

This international multicenter retrospective study (14 tertiary hospitals), included MCTD patients who fulfilled at least one historical MCTD classification criteria. ILD was defined by the presence of typical chest high-resolution computed tomography (HRCT) abnormalities. Factors associated with ILD were assessed at baseline. Long-term progressive ILD was assessed in MCTD-ILD patients with multiple forced vital capacity (FVC) measurements.

RESULTS

300 patients with MCTD were included. Mean age at diagnosis was 39.7 ± 15.4 years and 191 (63.7%) were women. Mean follow-up was 7.8 ± 5.5 years. At baseline, we identified several factors associated with ILD presence: older age (p = 0.01), skin thickening (p = 0.03), upper gastro-intestinal (GI) symptoms (p<0.001), FVC <80% (p<0.0001), diffusing capacity for carbon monoxide <80% (p<0.0001), anti-topoisomerase antibodies (p = 0.01), SSA/Ro antibodies (p = 0.02), cryoglobulinemia (p = 0.04) and elevated C-reactive protein (p<0.001). Patients with MTCD-ILD were more likely to be treated with synthetic immunosuppressant agents (p<0.001) in particular mycophenolate mofetil (p = 0.03). Digital ulcers (DU) were identified as a risk factor for FVC decline >10%. During follow-up mortality was higher in the MTCD-ILD group (p<0.001).

CONCLUSION

In this large international cohort of patients with MTCD, we identified different factors associated with ILD. Our findings also provide evidence that MCTD-ILD patients have increased mortality and that DU are associated with progressive lung disease.

Systemic Determinants of Exercise Intolerance in Patients With Fibrotic Interstitial Lung Disease and Severely Impaired DLCO

BACKGROUND

The precise mechanisms driving poor exercise tolerance in patients with fibrotic interstitial lung diseases (fibrotic ILDs) showing a severe impairment in single-breath lung diffusing capacity for carbon monoxide (DLCO < 40% predicted) are not fully understood. Rather than only reflecting impaired O2 transfer, a severely impaired DLCO may signal deranged integrative physiologic adjustments to exercise that jointly increase the burden of exertional symptoms in fibrotic ILD.

METHODS

Sixty-seven subjects (46 with idiopathic pulmonary fibrosis, 24 showing DLCO < 40%) and 22 controls underwent pulmonary function tests and an incremental cardiopulmonary exercise test with serial measurements of operating lung volumes and 0-10 Borg dyspnea and leg discomfort scores.

RESULTS

Subjects from the DLCO < 40% group showed lower spirometric values, more severe restriction, and lower alveolar volume and transfer coefficient compared to controls and participants with less impaired DLCO (P < .05). Peak work rate was ∼45% (vs controls) and ∼20% (vs DLCO > 40%) lower in the former group, being associated with lower (and flatter) O2 pulse, an earlier lactate (anaerobic) threshold, heightened submaximal ventilation, and lower SpO2 . Moreover, critically high inspiratory constrains were reached at lower exercise intensities in the DLCO < 40% group (P < .05). In association with the greatest leg discomfort scores, they reported the highest dyspnea scores at a given work rate. Between-group differences lessened or disappeared when dyspnea intensity was related to indexes of increased demand-capacity imbalance, that is, decreasing submaximal, dynamic ventilatory reserve, and inspiratory reserve volume/total lung capacity (P > .05).

CONCLUSIONS

A severely reduced DLCO in fibrotic ILD signals multiple interconnected derangements (cardiovascular impairment, an early shift to anaerobic metabolism, excess ventilation, inspiratory constraints, and hypoxemia) that ultimately lead to limiting respiratory (dyspnea) and peripheral (leg discomfort) symptoms. DLCO < 40%, therefore, might help in clinical decision-making to indicate the patient with fibrotic ILD who might derive particular benefit from pharmacologic and non-pharmacologic interventions aimed at lessening these systemic abnormalities.

Histogram-based analysis in progressive pulmonary fibrosis: relationships between pulmonary functional tests and HRCT indexes

OBJECTIVES

To investigate relationships between histogram-based high-resolution CT (HRCT) indexes and pulmonary function tests (PFTs) in interstitial lung diseases.

METHODS

Forty-nine patients having baseline and 1-year HRCT examinations and PFTs were investigated. Histogram-based HRCT indexes were calculated; strength of associations with PFTs was investigated using Pearson correlation. Patients were divided into progressive and non-progressive groups. HRCT indexes were compared between the two groups using the U-test; within each group, baseline and follow-up Wilcoxon analysis was performed. Receiver operating characteristic analysis was used for predicting disease progression.

RESULTS

At baseline, moderate correlations were observed considering kurtosis and diffusion capacity of the lungs for carbon monoxide (DLCO) (r = 0.54) and skewness and DLCO (r = 0.559), whereas weak but significant correlations were observed between forced vital capacity and kurtosis (r = 0.368, p = 0.009) and forced vital capacity and skewness (r = 0.391, p = 0.005). Negative correlations were reported between HAA% and PFTs (from r = -0.418 up to r = -0.507). At follow-up correlations between quantitative indexes and PFTs were also moderate, except for high attenuation area (HAA)% -700 and DLCO (r = -0.397). In progressive subgroup, moderate and strong correlations were found between DLCO and HRCT indexes (r = 0.595 kurtosis, r = 0.672 skewness, r=-0. 598 HAA% -600 and r = -0.626 HAA% -700). At follow-up, we observed significant differences between the two groups for kurtosis (p = 0.029), HAA% -600 (p = 0.04) and HAA% -700 (p = 0.02). To predict progression, ROC analysis reported sensitivity of 90.9% and specificity of 51.9% using a threshold value of δ kurtosis <0.03.

CONCLUSION

At one year, moderate correlations suggest that progression could be assessed through HRCT quantification.

ADVANCES IN KNOWLEDGE

This study promotes histogram-based HRCT indexes in the assessment of progressive pulmonary fibrosis.

Walking the path of treatable traits in interstitial lung diseases

Interstitial lung diseases (ILDs) are complex and heterogeneous diseases. The use of traditional diagnostic classification in ILD can lead to suboptimal management, which is worsened by not considering the molecular pathways, biological complexity, and disease phenotypes. The identification of specific "treatable traits" in ILDs, which are clinically relevant and modifiable disease characteristics, may improve patient's outcomes. Treatable traits in ILDs may be classified into four different domains (pulmonary, aetiological, comorbidities, and lifestyle), which will facilitate identification of related assessment tools, treatment options, and expected benefits. A multidisciplinary care team model is a potential way to implement a "treatable traits" strategy into clinical practice with the aim of improving patients' outcomes. Multidisciplinary models of care, international registries, and the use of artificial intelligence may facilitate the implementation of the "treatable traits" approach into clinical practice. Prospective studies are needed to test potential therapies for a variety of treatable traits to further advance care of patients with ILD.

The molecular mechanism underlying dermatomyositis related interstitial lung disease: evidence from bioinformatic analysis and in vivo validation

Background

Dermatomyositis (DM) is an autoimmune and inflammatory disease that can affect the lungs, causing interstitial lung diseases (ILD). However, the exact pathophysiological mechanisms underlying DM-ILD are unknown. Idiopathic pulmonary fibrosis (IPF) belongs to the broader spectrum of ILD and evidence shows that common pathologic pathways might lie between IPF and DM-ILD.

Methods

We retrieved gene expression profiles of DM and IPF from the Gene Expression Omnibus (GEO) and utilized weighted gene co-expression network analysis (WGCNA) to reveal their co-expression modules. We then performed a differentially expressed gene (DEG) analysis to identify common DEGs. Enrichment analyses were employed to uncover the hidden biological pathways. Additionally, we conducted protein-protein interaction (PPI) networks analysis, cluster analysis, and successfully found the hub genes, whose levels were further validated in DM-ILD patients. We also examined the relationship between hub genes and immune cell abundance in DM and IPF. Finally, we conducted a common transcription factors (TFs)-genes network by NetworkAnalyst.

Results

WGCNA revealed 258 intersecting genes, while DEG analysis identified 66 shared genes in DM and IPF. All of these genes were closely related to extracellular matrix and structure, cell-substrate adhesion, and collagen metabolism. Four hub genes (POSTN, THBS2, COL6A1, and LOXL1) were derived through intersecting the top 30 genes of the WGCNA and DEG sets. They were validated as active transcripts and showed diagnostic values for DM and IPF. However, ssGSEA revealed distinct infiltration patterns in DM and IPF. These four genes all showed a positive correlation with immune cells abundance in DM, but not in IPF. Finally, we identified one possible key transcription factor, MYC, that interact with all four hub genes.

Conclusion

Through bioinformatics analysis, we identified common hub genes and shared molecular pathways underlying DM and IPF, which provides valuable insights into the intricate mechanisms of these diseases and offers potential targets for diagnostic and therapeutic interventions.

Cyclodextrin MOFs modified dry powder inhalers quadruple bioavailability of luteolin to ameliorate fibrosing interstitial lung disease

Fibrosing interstitial lung disease (ILD) is a pathological condition that is highly heterogeneous and lethal, and has few effective treatment choices. Other than pirfenidone and nintedanib for the therapy of idiopathic pulmonary fibrosis, no medications are currently licensed for the treatment of ILD. Luteolin is a common flavonoid with multiple biological effects such as anti-inflammation but with poor solubility and absorption. In this study, we loaded luteolin into γ-cyclodextrin metal-organic frameworks (CD-MOFs) to deliver the medicine to the lungs using dry powder inhalers; in vitro pulmonary deposition results showed LUT@CDMOF had a high fine particle fraction (FPF) (59.77 ± 3.48%). LUT@CDMOF effectively inhibited ILD progression in the BLM-induced fibrosing ILD model rats. When compared to oral administration, the inhalation of LUT@CDMOF dry powder in rats showed considerable improvements in absorption and bioavailability, with a tmax of 0.08 h and a high absolute bioavailability (82%) of LUT (The AUC(0-t) and Cmax of inhal. LUT@CDMOF respectively increased about 4.03 times and 9.11 times, when compared with the i.g. LUT group). These studies demonstrate the potent anti-inflammatory activities of LUT@CDMOF. The inhaled LUT@CDMOF might be considered as a promising new strategy in the treatment of fibrosing ILD.

Mechanotransductive receptor Piezo1 as a promising target in the treatment of fibrosis diseases

Fibrosis could happen in every organ, leading to organic malfunction and even organ failure, which poses a serious threat to global health. Early treatment of fibrosis has been reported to be the turning point, therefore, exploring potential correlates in the pathogenesis of fibrosis and how to reverse fibrosis has become a pressing issue. As a mechanism-sensitive cationic calcium channel, Piezo1 turns on in response to changes in the lipid bilayer of the plasma membrane. Piezo1 exerts multiple biological roles, including inhibition of inflammation, cytoskeletal stabilization, epithelial-mesenchymal transition, stromal stiffness, and immune cell mechanotransduction, interestingly enough. These processes are closely associated with the development of fibrotic diseases. Recent studies have shown that deletion or knockdown of Piezo1 attenuates the onset of fibrosis. Therefore, in this paper we comprehensively describe the biology of this gene, focusing on its potential relevance in pulmonary fibrosis, renal fibrosis, pancreatic fibrosis, and cardiac fibrosis diseases, except for the role of drugs (agonists), increased intracellular calcium and mechanical stress using this gene in alleviating fibrosis.

Lung Magnetic Resonance Imaging for Prediction of Progression in Patients With Nonidiopathic Pulmonary Fibrosis Interstitial Lung Disease: A Pilot Study

PURPOSE

Correlate magnetic resonance imaging (MRI) parameters at baseline with disease progression in nonidiopathic pulmonary fibrosis interstitial lung disease (ILD).

MATERIALS AND METHODS

Prospective observational cohort study, in which patients with non-idiopathic pulmonary fibrosis ILD underwent MRI at baseline (1.5 T). T2-weighted images (T2-WI) were acquired by axial free-breathing respiratory-gated fat-suppressed "periodically rotated overlapping parallel lines with enhanced reconstruction" and T1-weighted images (T1-WI) by coronal end-expiratory breath-hold fat-suppressed "volumetric interpolated breath-hold examination" sequences, before and at time points T1, T3, T5, and T10 minutes after gadolinium administration. After MRI segmentation, signal intensity values were extracted by dedicated software. Percentage of the ILD volume and a ratio between signal intensity of ILD (SIILD) and normal lung (SInormal lung) were calculated for T2-WI; percentage of signal intensity (%SI) at each time point, time to peak enhancement, and percent relative enhancement of ILD in comparison with normal lung (%SIILD/normal lung) were calculated for T1-WI. MRI parameters at baseline were correlated with diagnosis of disease progression and variation in percent predicted forced vital capacity (%FVC) and diffusing capacity of the lung for carbon monoxide after 12 months.

RESULTS

Comprehensive MRI evaluation (T2-WI and T1-WI) was performed in 21 of the 25 patients enrolled (68% females; mean age: 62.6 y). Three of the 24 patients who completed follow-up fulfilled criteria for disease progression. Baseline T2-WI SIILD/SInormal lung was higher for the progression group (P = 0.052). T2-WI SIILD/SInormal lung and T1-WI %SIILD/normal lung at T1 were positively correlated with the 12-month variation in %FVC (r = 0.495, P = 0.014 and r = 0.489, P= 0.034, respectively).

CONCLUSIONS

Baseline MRI parameters correlate with %FVC decline after 12 months.

New therapeutic approaches against pulmonary fibrosis

Pulmonary fibrosis is the end-stage change of a large class of lung diseases characterized by the proliferation of fibroblasts and the accumulation of a large amount of extracellular matrix, accompanied by inflammatory damage and tissue structure destruction, which also shows the normal alveolar tissue is damaged and then abnormally repaired resulting in structural abnormalities (scarring). Pulmonary fibrosis has a serious impact on the respiratory function of the human body, and the clinical manifestation is progressive dyspnea. The incidence of pulmonary fibrosis-related diseases is increasing year by year, and no curative drugs have appeared so far. Nevertheless, research on pulmonary fibrosis have also increased in recent years, but there are no breakthrough results. Pathological changes of pulmonary fibrosis appear in the lungs of patients with coronavirus disease 2019 (COVID-19) that have not yet ended, and whether to improve the condition of patients with COVID-19 by means of the anti-fibrosis therapy, which are the questions we need to address now. This review systematically sheds light on the current state of research on fibrosis from multiple perspectives, hoping to provide some references for design and optimization of subsequent drugs and the selection of anti-fibrosis treatment plans and strategies.

Hydrolysable tannins as a potential therapeutic drug for the human fibrosis-associated disease

Fibrosis is a pathological change with abnormal tissue regeneration due to a response to persistent injury, which is extensively related to organ damage and failure, leading to high morbidity and mortality worldwide. Although the pathogenesis of fibrosis has been comprehensively elucidated, there are few effective therapies for treating fibrotic diseases. Natural products are increasingly regarded as an effective strategy for fibrosis with numerous favorable functions. Hydrolysable tannins (HT) are a type of natural products that have the potential to treat the fibrotic disease. In this review, we describe some biological activities and the therapeutic prospects of HT in organ fibrosis. Furthermore, the underlying mechanisms of inhibition of HT on fibrotic organs in relation to inflammation, oxidative stress, epithelial-mesenchymal transition, fibroblast activation and proliferation, and extracellular matrix accumulation are discussed. Understanding the mechanism of HT against fibrotic diseases will provide a new strategy for the prevention and attenuation of fibrosis progression.

NETosis promotes chronic inflammation and fibrosis in systemic lupus erythematosus and COVID-19

Pulmonary fibrosis, a serious complication of systemic lupus erythematosus (SLE) and coronavirus disease 2019 (COVID-19), leads to irreversible lung damage. However, the underlying mechanism of this condition remains unclear. In this study, we revealed the landscape of transcriptional changes in lung biopsies from individuals with SLE, COVID-19-induced pulmonary fibrosis, and idiopathic pulmonary fibrosis (IPF) using histopathology and RNA sequencing, respectively. Despite the diverse etiologies of these diseases, lung expression of matrix metalloproteinase genes in these diseases showed similar patterns. Particularly, the differentially expressed genes were significantly enriched in the pathway of neutrophil extracellular trap formation, showing similar enrichment signature between SLE and COVID-19. The abundance of Neutrophil extracellular traps (NETs) was much higher in the lungs of individuals with SLE and COVID-19 compared to those with IPF. In-depth transcriptome analyses revealed that NETs formation pathway promotes epithelial-mesenchymal transition (EMT). Furthermore, stimulation with NETs significantly up-regulated α-SMA, Twist, Snail protein expression, while decreasing the expression of E-cadherin protein in vitro. This indicates that NETosis promotes EMT in lung epithelial cells. Given drugs that are efficacious in degrading damaged NETs or inhibiting NETs production, we identified a few drug targets that were aberrantly expressed in both SLE and COVID-19. Among these targets, the JAK2 inhibitor Tofacitinib could effectively disrupted the process of NETs and reversed NET-induced EMT in lung epithelial cells. These findings support that the NETs/EMT axis, activated by SLE and COVID-19, contributes to the progression of pulmonary fibrosis. Our study also highlights that JAK2 as a potential target for the treatment of fibrosis in these diseases.

Add-on therapy for pulmonary fibrosis, a forthcoming era with implications for practice: the BI 101550 and RELIEF trials

The therapeutic landscape for idiopathic pulmonary fibrosis (IPF) and progressive fibrosing interstitial lung disease (PFILD) is increasingly complex, with add-on antifibrotic options now in clinical trials, or available for patients progressing on first-line therapy in both conditions. Here, we review two recent trials of potential add-on therapeutic options, the BI 101550 and RELIEF trials. BI 101550 was a phase 2 randomised control trial (RCT) of a novel phosphodiesterase-4 inhibitor in patients with IPF, with a primary end-point of change in forced vital capacity (ΔFVC) (in mL) at 12 weeks. The RELIEF trial was a phase 2 RCT in patients with PFILD, with a primary end-point of ΔFVC (absolute % predicted) over 48 weeks. Whilst the BI 101550 and RELIEF trials showed positive results in their primary end-points, the strengths and weaknesses of both trials are discussed with importance for their interpretation and clinical impact. We review current clinical practice in IPF and PFILD and place the BI101550 and RELIEF trial results in context, highlighting advances and problems with antifibrotic therapies.

Commentary on

Richeldi L, et al. Trial of a preferential phosphodiesterase 4B inhibitor for idiopathic pulmonary fibrosis. N Engl J Med 2022; 386: 2178-2187.Behr J, et al. Pirfenidone in patients with progressive fibrotic interstitial lung diseases other than idiopathic pulmonary fibrosis (RELIEF): a double-blind, randomised, placebo-controlled, phase 2b trial. Lancet Respir Med 2021; 9: 476-486.

Comparison of high-intensity interval training versus moderate-intensity continuous training in pulmonary rehabilitation for interstitial lung disease: a randomised controlled pilot feasibility trial

OBJECTIVES

This study aimed to investigate the feasibility and efficacy of high-intensity interval training (HIIT) compared with moderate-intensity continuous training (MICT) in pulmonary rehabilitation (PR) for people with interstitial lung disease (ILD).

DESIGN

Single-centre, randomised controlled feasibility, pilot trial.

SETTING

Patients were recruited from the chest clinic of a tertiary ILD centre and attended circuit-based PR in the hospital's gym, followed by a personalised 6-month community programme.

PARTICIPANTS

58 patients, stratified per ILD type, were randomised into two groups: 33 to HIIT (18 males:15 females) (mean age (SD): 70.2 (11.4) years) and 25 to the MICT exercise mode (14 males:11 females) (mean age (SD): 69.8 (10.8) years).

INTERVENTIONS

8-week, twice weekly, circuit-based PR programme of exercise and education, followed by a personalised 6-month community exercise programme.

OUTCOME MEASURES

Feasibility outcomes included staff-to-patient ratio and dropout rates per group. Primary outcome was the 6 min walk distance (6MWD). Secondary outcomes included the sniff nasal pressure, mouth inspiratory and expiratory pressures, handgrip and quadriceps strength and health status. Random-effects models were used to evaluate average variation in outcomes through time across the two groups.

RESULTS

The 6MWD peaked earlier with HIIT compared with MICT (at 4 months vs 5 months) but values were lower at peak (mean (95% CI): 26.3 m (3.5 to 49.1) vs 51.6 m (29.2 to 73.9)) and declined faster at 6 months post-PR. Secondary outcomes showed similar faster but smaller improvements with HIIT over MICT and more consistent maintenance 6 months post-PR with MICT than HIIT.

CONCLUSIONS

HIIT is feasible in circuit-based ILD PR programmes and provides quick improvements but requires closer supervision of training and resources than MICT and benefits may be less well sustained. This would make it a less attractive option for clinical PR programmes. A definitive, multicentre randomised controlled trial is required to address the role of HIIT in ILD.

TRIAL REGISTRATION NUMBER

ISRCTN55846300.

Adipose-derived mesenchymal stem cell therapy for reverse bleomycin-induced experimental pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive respiratory disease. Arguably, the complex interplay between immune cell subsets, coupled with an incomplete understanding of disease pathophysiology, has hindered the development of successful therapies. Despite efforts to understand its pathophysiology and develop effective treatments, IPF remains a fatal disease, necessitating the exploration of new treatment options. Mesenchymal stromal/stem cell (MSC) therapy has shown promise in experimental models of IPF, but further investigation is needed to understand its therapeutic effect. This study aimed to assess the therapeutic effect of adipose-derived mesenchymal stem cells in a bleomycin-induced pulmonary fibrosis model. First, MSC cells were obtained from mice and characterized using flow cytometry and cell differentiation culture methods. Then adult C57BL/6 mice were exposed to endotracheal instillation of bleomycin and concurrently treated with MSCs for reversal models on day 14. Experimental groups were evaluated on days 14, 21, or 28. Additionally, lung fibroblasts challenged with TGF-β1 were treated with MSCs supernatant or MSCs to explore the mechanisms underlying of pulmonary fibrosis reversal. Mesenchymal stem cells were successfully isolated from mouse adipose tissue and characterized based on their differentiation ability and cell phenotype. The presence of MSCs or their supernatant stimulated the proliferation and migration of lung fibrotic cells. MSCs supernatant reduced lung collagen deposition, improved the Ashcroft score and reduced the gene and protein expression of lung fibrosis-related substances. Bleomycin-challenged mice exhibited severe septal thickening and prominent fibrosis, which was effectively reversed by MSCs treatment. MSC supernatant could suppress the TGF-β1/Smad signaling pathway and supernatant promotes fibroblast autophagy. In summary, this study demonstrates that MSCs supernatant treatment is as effective as MSCs in revert the core features of bleomycin-induced pulmonary fibrosis. The current study has demonstrated that MSCs supernatant alleviates the BLM-induced pulmonary fibrosis in vivo. In vitro experiments further reveal that MSC supernatant could suppress the TGF-β1/Smad signaling pathway to inhibit the TGF-β1-induced fibroblast activation, and promotes fibroblast autophagy by Regulating p62 expression. These findings contribute to the growing body of evidence supporting the therapeutic application of MSCs in cell therapy medicine for IPF.

A Review: The Potential Involvement of Growth Arrest-Specific 6 and Its Receptors in the Pathogenesis of Lung Damage and in Coronavirus Disease 2019

The tyrosine kinase receptors of the TAM family-Tyro3, Axl and Mer-and their main ligand Gas6 (growth arrest-specific 6) have been implicated in several human diseases, having a particularly important role in the regulation of innate immunity and inflammatory response. The Gas6/TAM system is involved in the recognition of apoptotic debris by immune cells and this mechanism has been exploited by viruses for cell entry and infection. Coronavirus disease 2019 (COVID-19) is a multi-systemic disease, but the lungs are particularly affected during the acute phase and some patients may suffer persistent lung damage. Among the manifestations of the disease, fibrotic abnormalities have been observed among the survivors of COVID-19. The mechanisms of COVID-related fibrosis remain elusive, even though some parallels may be drawn with other fibrotic diseases, such as idiopathic pulmonary fibrosis. Due to the still limited number of scientific studies addressing this question, in this review we aimed to integrate the current knowledge of the Gas6/TAM axis with the pathophysiological mechanisms underlying COVID-19, with emphasis on the development of a fibrotic phenotype.

Spectrum of high-resolution computed tomography pattern in lungs in patients with connective tissue disorders

Background

Connective tissue disease associated with interstitial lung disease, or CT-ILD, is a lung condition that affects a large number of patients with a connective tissue disease.

Objective

Our aim in this study is to correlation between images of high-resolution computed tomography (HRCT) of different connective tissue diseases associated interstitial lung diseases (CTD-ILDs).

Methods

We shall be aiming to investigate the feasibility of HRCT imaging and thereby avoid lung biopsy in such patients.

Results

Rheumatoid arthritis predominantly presented with usual interstitial pneumonia (UIP) (47.8%), followed by nonspecific interstitial pneumonia (NSIP) (30.4%). Mixed connective tissue disorder predominantly presented with NSIP and UIP (42.8%), followed by organizing pneumonia (OP) (14.2%). Systemic lupus erythematosus predominantly presented with UIP (38.8%), followed by NSIP (27.7%). Sjogren's syndrome predominantly presented with lymphocytic interstitial pneumonia (40%), followed by UIP (26.6%). Scleroderma predominantly presented with UIP (45.4%), followed by NSIP (36.4%). Sarcoidosis predominantly presented with UIP (75%), followed by NSIP (25%). Dermatomyositis predominantly presented with NSIP (50%), followed by UIP and OP each (25%).

Conclusion

Both clinicians and radiologists should be aware of the expected evolution of HRCT changes in a variety of CT-ILDs.

Clinical Utility of Bronchoalveolar Lavage Neutrophilia and Biomarkers for Evaluating Severity of Chronic Fibrosing Interstitial Lung Diseases

Introduction It is hypothesized that bronchoalveolar lavage (BAL) neutrophilia, Krebs von den Lungen-6 (KL-6), and C-reactive protein (CRP) predict the severity of chronic fibrosing interstitial lung diseases (CF-ILDs). Methods This cross-sectional study enrolled 30 CF-ILD patients. Using Pearson's correlation analysis, BAL neutrophils, KL-6, and CRP were correlated with forced vital capacity (FVC), diffusing lung capacity for carbon monoxide (DLCO), six-minute walk distance (6MWD), partial pressure of oxygen (PaO2), computed tomography fibrosis score (CTFS), and pulmonary artery systolic pressure (PASP). Using the receiver operator characteristic (ROC) curve, BAL KL-6 and CRP were evaluated against FVC% and DLCO% in isolation and combination with BAL neutrophilia for predicting the severity of CF-ILDs. Results BAL neutrophilia significantly correlated only with FVC% (r = -0.38, P = 0.04) and DLCO% (r = -0.43, P = 0.03). BAL KL-6 showed a good correlation with FVC% (r = -0.44, P < 0.05) and DLCO% (r = -0.50, P = 0.02), while BAL CRP poorly correlated with all parameters (r = 0.0-0.2). Subset analysis of BAL CRP in patients with CTFS ≤ 15 showed a better association with FVC% (r = -0.28, P = 0.05) and DLCO% (r = -0.36, P = 0.04). BAL KL-6 cut-off ≥ 72.32 U/ml and BAL CRP ≥ 14.55 mg/L predicted severe disease with area under the curve (AUC) values of 0.77 and 0.71, respectively. The combination of BAL neutrophilia, KL-6, and CRP predicted severity with an AUC value of 0.89. Conclusion The combination of BAL neutrophilia, KL-6, and CRP facilitates the severity stratification of CF-ILDs complementing existing severity parameters.

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.

Immune-mediated lung diseases: A narrative review

The role of immunity in the pathogenesis of various pulmonary diseases, particularly interstitial lung diseases (ILDs), is being increasingly appreciated as mechanistic discoveries advance our knowledge in the field. Immune-mediated lung diseases demonstrate clinical and immunological heterogeneity and can be etiologically categorized into connective tissue disease (CTD)-associated, exposure-related, idiopathic, and other miscellaneous lung diseases including sarcoidosis, and post-lung transplant ILD. The immunopathogenesis of many of these diseases remains poorly defined and possibly involves either immune dysregulation, abnormal healing, chronic inflammation, or a combination of these, often in a background of genetic susceptibility. The heterogeneity and complex immunopathogenesis of ILDs complicate management, and thus a collaborative treatment team should work toward an individualized approach to address the unique needs of each patient. Current management of immune-mediated lung diseases is challenging; the choice of therapy is etiology-driven and includes corticosteroids, immunomodulatory drugs such as methotrexate, cyclophosphamide and mycophenolate mofetil, rituximab, or other measures such as discontinuation or avoidance of the inciting agent in exposure-related ILDs. Antifibrotic therapy is approved for some of the ILDs (e.g., idiopathic pulmonary fibrosis) and is being investigated for many others and has shown promising preliminary results. A dire need for advances in the management of immune-mediated lung disease persists in the absence of standardized management guidelines.

Use of a pulmosphere model to evaluate drug antifibrotic responses in interstitial lung diseases

BACKGROUND

Interstitial lung diseases (ILD) encompass a heterogenous group of diffuse parenchymal lung disorders characterized by variable degrees of inflammation and fibrosis. Pretherapeutic clinical testing models for such diseases can serve as a platform to test and develop effective therapeutic strategies. In this study, we developed patient derived 3D organoid model to recapitulate the disease process of ILDs. We characterized the inherent property of invasiveness in this model and tested for antifibrotic responses with an aim to develop a potential platform for personalized medicine in ILDs.

METHODS

In this prospective study, 23 patients with ILD were recruited and underwent lung biopsy. 3D organoid-based models (pulmospheres) were developed from the lung biopsy tissues. Pulmonary functioning testing and other relevant clinical parameters were collected at the time of enrollment and follow up visits. The patient derived pulmospheres were compared to normal control pulmospheres obtained from 9 explant lung donor samples. These pulmospheres were characterized by their invasive capabilities and responsiveness to the antifibrotic drugs, pirfenidone and nintedanib.

RESULTS

Invasiveness of the pulmospheres was measured by the zone of invasiveness percentage (ZOI%). The ILD pulmospheres (n = 23) had a higher ZOI% as compared to control pulmospheres (n = 9) (516.2 ± 115.6 versus 54.63 ± 19.6 respectively. ILD pulmospheres were responsive to pirfenidone in 12 of the 23 patients (52%) and responsive to nintedanib in all 23 patients (100%). Pirfenidone was noted to be selectively responsive in patients with connective tissue disease related ILD (CTD-ILD) at low doses. There was no correlation between the basal pulmosphere invasiveness, response to antifibrotics, and FVC change (Δ FVC).

CONCLUSIONS

The 3D pulmosphere model demonstrates invasiveness which is unique to each individual subject and is greater in ILD pulmospheres as compared to controls. This property can be utilized to test responses to drugs such as antifibrotics. The 3D pulmosphere model could serve as a platform for the development of personalized approaches to therapeutics and drug development in ILDs and potentially other chronic lung diseases.

Clinical features of idiopathic pleuroparenchymal fibroelastosis with progressive phenotype showing a decline in forced vital capacity

BACKGROUND

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is heterogeneous, with some patients showing a progressive decline in forced vital capacity (FVC). However, the clinical features of these cases with progressive phenotypes remain unknown.

METHODS

This retrospective study included 48 patients diagnosed with IPPFE who underwent longitudinal pulmonary function tests at our institution from 2005 to 2021. The progressive phenotype was defined as a relative decline of ≥10% in %FVC within two years from diagnosis of IPPFE, and its clinical features were evaluated.

RESULTS

Of the 48 patients, 23 (47.9%) were classified as progressive IPPFE. They were significantly older with a higher rate of dyspnea, fine crackles on chest auscultation, lower-lobe usual interstitial pneumonia (UIP) pattern on high-resolution computed tomography, and lower %FVC at diagnosis than non-progressive IPPFE. Additionally, progressive IPPFE had a significantly higher rate of long-term oxygen therapy requirement, the incidence of pneumothorax, and weight loss after diagnosis, which showed worse survival than non-progressive IPPFE. The relative decline in %FVC and weight loss showed a significant positive correlation. Multivariate analysis revealed that lower body mass index tended to predict early progression, and the coexistence of lower-lobe UIP pattern was significantly associated with early progression. A decline in %FVC was an independent poor prognostic factor in IPPFE.

CONCLUSIONS

With a progressive decline in %FVC, IPPFE often has an advanced stage at diagnosis and lower-lobe UIP pattern and is associated with weight loss and worse survival.

Progressive pulmonary fibrosis: an expert group consensus statement

This expert group consensus statement emphasises the need for standardising the definition of progressive fibrosing interstitial lung diseases (F-ILDs), with an accurate initial diagnosis being of paramount importance in ensuring appropriate initial management. Equally, case-by-case decisions on monitoring and management are essential, given the varying presentations of F-ILDs and the varying rates of progression. The value of diagnostic tests in risk stratification at presentation and, separately, the importance of a logical monitoring strategy, tailored to manage the risk of progression, are also stressed. The term "progressive pulmonary fibrosis" (PPF) exactly describes the entity that clinicians often face in practice. The importance of using antifibrotic therapy early in PPF (once initial management has failed to prevent progression) is increasingly supported by evidence. Artificial intelligence software for high-resolution computed tomography analysis, although an exciting tool for the future, awaits validation. Guidance is provided on pulmonary rehabilitation, oxygen and the use of non-invasive ventilation focused specifically on the needs of ILD patients with progressive disease. PPF should be differentiated from acute deterioration due to drug-induced lung toxicity or other forms of acute exacerbations. Referral criteria for a lung transplant are discussed and applied to patient needs in severe diseases where transplantation is not realistic, either due to access limitations or transplantation contraindications. In conclusion, expert group consensus guidance is provided on the diagnosis, treatment and monitoring of F-ILDs with specific focus on the recognition of PPF and the management of pulmonary fibrosis progressing despite initial management.

Impaired Dynamic Response of Oxygen Saturation During the 6-min Walk Test Is Associated With Mortality in Chronic Fibrosing Interstitial Pneumonia

BACKGROUND

The 6-min walk test (6MWT) is a common assessment of exercise-induced hypoxemia and exercise capacity used in patients with chronic fibrosing interstitial pneumonia (CFIP). However, whether the dynamic changes in SpO2 and heart rate during the 6MWT are associated with mortality in patients with CFIP has been undefined.

METHODS

This retrospective study enrolled 63 subjects with mild to severe CFIP who underwent the 6MWT. Subjects with CFIP were divided into 2 groups according to disease severity: mild, diffusing capacity of the lungs for carbon monoxide percentage predicted (%DLCO) > 55% and %FVC > 75%; and severe, %DLCO ≤ 55% and/or %FVC ≤ 75%. This study aimed to evaluate dynamic changes in the 6MWT including 6-min walk distance, change in SpO2 (ΔSpO2 ), SpO2 reduction time, SpO2 recovery time, change in heart rate (Δ heart rate), heart rate acceleration time, slope of heart rate acceleration, heart rate recovery at 1 min of rest after the 6MWT (HR-recovery), and dyspnea on exertion that are reflected by static pulmonary function and are related to exacerbation of CFIP and mortality.

RESULTS

Compared with subjects with mild CFIP, subjects with severe CFIP had significantly larger ΔSpO2 and longer SpO 2 reduction time and recovery time. The slope of heart rate, heart rate immediately after the 6MWT, and HR-recovery were lower in subjects with severe CFIP than in those with mild CFIP. In multiple regression analysis, percent vital capacity was significantly associated with SpO2 reduction time, and %DLCO was significantly associated with ΔSpO2 and SpO2 recovery time. Subjects with ΔSpO2 of > 10% and SpO2 recovery time of > 79 s had a significantly higher risk for exacerbation and mortality.

CONCLUSIONS

Dynamic changes in SpO2 and heart rate during the 6MWT were associated with risk for exacerbation and mortality in subjects with CFIP. Impaired dynamic response of SpO2 could reflect likelihood of exacerbation and increased mortality in CFIP.

Diagnosis and Pharmacologic Management of Fibrotic Interstitial Lung Disease

Interstitial lung disease is an umbrella term that encompasses a spectrum of parenchymal lung pathologies affecting the gas exchanging part of the lung. While many of these disease entities are not fibrotic in nature, a number can lead to pulmonary fibrosis which may or may not progress over time. Idiopathic pulmonary fibrosis is the prototypical, progressive fibrotic interstitial lung disease, which can lead to worsening hypoxemic respiratory failure and mortality within a number of years from the time of diagnosis. The importance of an accurate and timely diagnosis of interstitial lung diseases, which is needed to inform prognosis and guide clinical management, cannot be overemphasized. Developing a consensus diagnosis requires the incorporation of a variety of factors by a multidisciplinary team, which then may or may not determine a need for tissue sampling. Clinical management can be challenging given the heterogeneity of disease behavior and the paucity of controlled trials to guide decision making. This review addresses current paradigms and recent updates in the diagnosis and pharmacologic management of these fibrotic interstitial lung diseases.

Interstitial lung diseases specific measures in exercise interventions: A systematic review of measurement properties

BACKGROUND

Effects of exercise-based interventions (EBIs) on people with interstitial lung disease (ILD) are not yet fully understood. Reasons may include the limited use of ILD-specific measures and/or the lack of adequate information regarding their measurement properties. The purpose of this review was to summarize the ILD-specific outcome measures used in EBI studies and their measurement properties.

METHODS

This was a two-phase systematic review: phase 1 identified ILD-specific measures used in EBI studies; phase 2 reviewed their measurement properties. PubMed, Web of Science, Scopus, EBSCO and EMBASE were searched up to March 2021. One reviewer extracted data, and 2 reviewers independently assessed studies risk of bias as well as the quality of measurement properties using the Consensus-Based Standards for the Selection of Health Status Measurement Instruments (COSMIN) recommendations.

RESULTS

Phase 1 identified 18 records. The St George's Respiratory Questionnaire for Interstitial Pulmonary Fibrosis (SGRQ-IPF) was the only ILD-specific outcome measure used (n = 2 trials). Phase 2 resulted in 31 eligible records; measurement properties were reported for 12 measures. Measures presented sufficient content validity, internal consistency (Cronbach's alpha 0.61-0.96), test-retest reliability (intraclass correlation coefficient 0.39; 0.96), hypothesis testing and responsiveness but were insufficient for measurement error and indeterminate for cross-cultural and structural validity. The outcome measures King's Brief Interstitial Lung Disease and SGRQ-IPF had higher evidence of adequate measurement properties than other measures. Quality of the evidence was mostly very low to moderate.

CONCLUSIONS

ILD-specific outcome measures are used infrequently in EBI trials, and there is scarce information regarding their measurement properties.

DATABASE REGISTRATION

CRD42018112466.

Serum KL-6 as a Biomarker of Progression at Any Time in Fibrotic Interstitial Lung Disease

The development of a progressive phenotype of interstitial lung disease (ILD) is still unpredictable. Whereas tools to predict mortality in ILD exist, scores to predict disease progression are missing. The aim of this study was to investigate whether baseline serum KL-6 as an established marker to assess disease activity in ILD, alone or in combination with clinical variables, could improve stratification of ILD patients according to progression risk at any time. Consecutive patients with fibrotic ILD, followed at our institution between 2008 and 2015, were investigated. Disease progression was defined as relative decline of ≥10% in forced vital capacity (FVC) or ≥15% in diffusing capacity of the lung for carbon monoxide (DLco)% from baseline at any time. Serum KL-6 was measured using an automated immunoassay (Fujirebio Europe, Gent, Belgium). A stepwise logistic regression was performed to select variables to be included in the score. A total of 205 patients (49% idiopathic pulmonary fibrosis (IPF), 51% fibrotic nonspecific interstitial pneumonia (NSIP)) were included, of them 113 (55%) developed disease progression during follow up. Male gender (G) and serum KL-6 strata (K) were significant predictors of progression at regression analysis and were included in the GK score. A threshold of 2 GK score points was best for discriminating patients at high risk versus low risk to develop disease progression at any time. Serum KL-6 concentration, alone or combined in a simple score with gender, allows an effective stratification of ILD patients for risk of disease progression at any time.

Clinical Characteristics and Disease Course of Fibrosing Interstitial Lung Disease Patients in a Real-World Setting

Background and Objectives: This single-center retrospective study was conducted to describe clinical characteristics and the disease course of patients with interstitial lung diseases (ILD). Materials and Methods: The study included adult patients with fibrosing ILD (IPF, non-IPF fibrosing ILD (F-ILD), and non-IPF progressive pulmonary fibrosis (PPF)) treated between 2014 and 2017. Patients were followed annually from the first visit until the end of the study period in 2019. Data were collected from the Turku University Hospital data lake and analyzed using descriptive statistics. Results: 591 patients formed the patient cohort: 110 had IPF, 194 F-ILD, 142 PPF, and the remaining 145 patients were uncertain, F-ILD-U, whose disease progression nature could not be confirmed by FVC measurements. There were more males in each patient group and median age of the groups was similar, although there were younger patients in the PPF, F-ILD, and F-ILD-U groups. PPF patients had more UIP pattern than F-ILD patients. Exposure-related ILDs were clearly the most found ILD diagnoses for both PPF and F-ILD, followed by unclassifiable IIP. Baseline FVC % predicted reduction in every group was moderate. Half of the patients in each group had comorbidities, and the most common were cardiovascular diseases, diabetes, sleep apnea, and chronic lower respiratory diseases; F-ILD-U patients had malignant diseases as well. IPF patients had less medications than the other groups. Glucocorticoids were the most used medication in all patient groups. More PPF and F-ILD patients remained in the follow-up than IPF and F-ILD-U patients. Similarly, mortality of F-ILD-U was the highest, followed by IPF. Evolvement of lung function, oxygen use, and number of acute hospitalizations were similar for IPF and PPF patients whereas the corresponding results were always better for F-ILD patients. Conclusions: The disease course of IPF and PPF was similar, and PPF patient amount exceeded the amount of IPF patients.

Real-world impact of antifibrotics on prognosis in patients with progressive fibrosing interstitial lung disease

OBJECTIVE

No studies have demonstrated the real-world efficacy of antifibrotics for progressive fibrosing interstitial lung disease (PF-ILD). Therefore, we evaluated the efficacy of antifibrotics in patients with PF-ILD.

METHODS

We retrospectively reviewed the medical records of patients with ILD from January 2012 to July 2021. Patients were diagnosed with PF-ILD if they had ≥10% fibrosis on high-resolution CT (HRCT) and a relative forced vital capacity (FVC) decline of either ≥10% or >5% to <10% with clinical deterioration or progression of fibrosis on HRCT during overlapping windows of 2 years and with a %FVC of ≥45%. We compared FVC changes and overall survival (OS) between patients with and without antifibrotics. FVC changes were analysed using generalised estimating equations. We used inverse probability weighting (IPW) and statistical matching to adjust for covariates.

RESULTS

Of the 574 patients, 167 were diagnosed with PF-ILD (idiopathic pulmonary fibrosis (IPF), n=64; non-IPF, n=103). Antifibrotics improved the FVC decline in both IPF (p=0.002) and non-IPF (p=0.05) (IPW: IPF, p=0.015; non-IPF, p=0.031). Among patients with IPF, OS was longer in the antifibrotic group (log-rank p=0.001). However, among patients with non-IPF, OS was not longer in the antifibrotic group (p=0.3263) (IPW and statistical matching: IPF, p=0.0534 and p=0.0018; non-IPF, p=0.5663 and p=0.5618).

CONCLUSION

This is the first real-world study to show that antifibrotics improve the FVC decline in PF-ILD. However, among patients with non-IPF, we found no significant difference in mortality between those with and without antifibrotics. Future studies must clarify whether antifibrotics improve the prognosis of non-IPF.

Real-world utility of a genomic classifier in establishing a diagnosis of newly identified interstitial lung disease

BACKGROUND

Diagnosing interstitial lung disease (ILD) remains challenging. Guidelines recommend utilizing a multidisciplinary discussion (MDD) to review clinical and radiographic data and if diagnostic uncertainty persists, then to obtain histopathology. Surgical lung biopsy and transbronchial lung cryobiopsy (TBLC) are acceptable methods, but risks of complications may be prohibitive. The Envisia genomic classifier (EGC) represents another option to determine a molecular usual interstitial pneumonia (UIP) signature to facilitate an ILD diagnosis at MDD with high sensitivity and specificity. We evaluated the concordance between TBLC and EGC at MDD and the safety of this procedure.

METHODS

Demographic data, pulmonary function values, chest imaging pattern, procedural information, and MDD diagnosis were recorded. Concordance was defined as agreement between the molecular EGC results and histopathology from TBLC in the context of the patient's High Resolution CT pattern.

RESULTS

49 patients were enrolled. Imaging demonstrated a probable (n = 14) or indeterminate (n = 7) UIP pattern in 43% and an alternative pattern in 57% (n = 28). EGC results were positive for UIP in 37% (n = 18) and negative in 63% (n = 31). MDD diagnosis was obtained in 94% (n = 46) with fibrotic hypersensitivity pneumonitis (n = 17, 35%) and IPF (n = 13, 27%) most common. The concordance between EGC and TBLC at MDD was 76% (37/49) with discordant results seen in 24% (12/49) of patients.

CONCLUSIONS

There appears to be reasonable concordance between EGC and TBLC results at MDD. Efforts clarifying the contributions of these tools to an ILD diagnosis may help identify specific patient populations that may benefit from a tailored diagnostic approach.

Impact of Antifibrotic Treatment on Postoperative Complications in Patients with Interstitial Lung Diseases Undergoing Lung Transplantation: A Systematic Review and Meta-Analysis

Antifibrotic treatment has been approved for reducing disease progression in fibrotic interstitial lung disease (ILD). As a result of increased bleeding risk, some experts suggest cessation of antifibrotics prior to lung transplantation (LT). However, extensive knowledge regarding the impact of antifibrotic treatment on postoperative complications remains unclear. We performed a comprehensive search of several databases from their inception through to 30 September 2021. Original studies were included in the final analysis if they compared postoperative complications, including surgical wound dehiscence, anastomosis complication, bleeding complications, and primary graft dysfunction, between those with and without antifibrotic treatment undergoing LT. Of 563 retrieved studies, 6 studies were included in the final analysis. A total of 543 ILD patients completing LT were included, with 161 patients continuing antifibrotic treatment up to the time of LT and 382 without prior treatment. Antifibrotic treatment was not significantly associated with surgical wound dehiscence (RR 1.05; 95% CI, 0.31-3.60; I² = 0%), anastomotic complications (RR 0.88; 95% CI, 0.37-2.12; I² = 31%), bleeding complications (RR 0.76; 95% CI, 0.33-1.76; I² = 0%), or primary graft dysfunction (RR 0.87; 95% CI, 0.59-1.29; I² = 0%). Finally, continuing antifibrotic treatment prior to LT was not significantly associated with decreased 1-year mortality (RR 0.80; 95% CI, 0.41-1.58; I² = 0%). Our study suggests a similar risk of postoperative complications in ILD patients undergoing LT who received antifibrotic treatment compared to those not on antifibrotic therapy.

Pulmonary Fibrosis and Progressive Pulmonary Fibrosis in a Prospective Registry of Interstitial Lung Diseases in Eastern Siberia

Interstitial lung diseases (ILD) are part of a large heterogeneous group of diseases that differ in many ways (in their cause, clinical presentation, and response to therapy, etc.), but there are similar pathophysiological mechanisms involved in the development of the inflammation and/or fibrosis of the lungs. Currently, several criteria for pulmonary fibrosis (PF) and progressive pulmonary fibrosis (PPF) are proposed, and the information on the prevalence and characteristics of these conditions is limited. The aim of this study was to evaluate the spectrum of PF and PPF according to the registry of patients with ILD in eastern Siberia. Materials and methods: The study included patients with ILD from all of the medical institutions in the Irkutsk region (eastern Siberia). Each case of ILD (n = 270) was reviewed by a multidisciplinary discussion panel. The ILD patient registry included information on the clinical findings, history, pulmonary function tests, high-resolution computed tomography (HRCT), and histological findings. The follow-up period for the patients varied from 1 to 5 years. Results: Pulmonary fibrosis was detected by HRCT in 104 patients with ILD (38.5%). PF was present in 100% of the patients with IPF and SS-ILD, in 90.9% of the patients with CHP, in 71.4% of the patients with NSIP, and in 60% of the patients with RA-ILD. Sixty-two patients met the criteria for PPF (23.0% of the entire ILD cohort and 59.6% of the patients with PF). PPF occurred most often in the patients with IPF, CHP, IPAF, and SSc-ILD: 100%, 72.7%, 40%, and 38.5% of them, respectively. The variables associated with fibrosis progression included Velcro crackles (OR 18.3, p < 0.001) and late diagnosis (OR 4.1, p < 0.001). Conclusion: Pulmonary fibrosis and progressive pulmonary fibrosis are common in patients with ILD. The high mortality rate of PPF dictates the need for the active, early detection of a progressive fibrosing course of a wide range of ILD and suggests that further studies assessing the effectiveness of the interventions might be warranted.

Nintedanib in an elderly non-small-cell lung cancer patient with severe steroid-refractory checkpoint inhibitor-related pneumonitis: A case report and literature review

Immune checkpoint inhibitors tremendously improve cancer prognosis; however, severe-grade immune-related adverse events may cause premature death. Current recommendations for checkpoint inhibitor-related pneumonitis (CIP) treatment are mainly about immunosuppressive therapy, and anti-fibrotic agents are also needed, especially for patients with poor response to corticosteroids and a longer pneumonitis course. This is because fibrotic changes play an important role in the pathological evolution of CIP. Here, we report a case demonstrating that nintedanib is a promising candidate drug for CIP management or prevention, as it has potent anti-fibrotic efficacy and a safety profile. Moreover, nintedanib could partially inhibit tumor growth in patients with non-small-cell lung cancer, and its efficacy can be improved in combination with other anti-tumor therapies.

Interstitial lung abnormalities in a large clinical lung cancer screening cohort: association with mortality and ILD diagnosis

BACKGROUND

Interstitial lung abnormalities (ILA) are CT findings suggestive of interstitial lung disease in individuals without a prior diagnosis or suspicion of ILD. Previous studies have demonstrated that ILA are associated with clinically significant outcomes including mortality. The aim of this study was to determine the prevalence of ILA in a large CT lung cancer screening program and the association with clinically significant outcomes including mortality, hospitalizations, cancer and ILD diagnosis.

METHODS

This was a retrospective study of individuals enrolled in a CT lung cancer screening program from 2012 to 2014. Baseline and longitudinal CT scans were scored for ILA per Fleischner Society guidelines. The primary analyses examined the association between baseline ILA and mortality, all-cause hospitalization, and incidence of lung cancer. Kaplan-Meier plots were generated to visualize the associations between ILA and lung cancer and all-cause mortality. Cox regression proportional hazards models were used to test for this association in both univariate and multivariable models.

RESULTS

1699 subjects met inclusion criteria. 41 (2.4%) had ILA and 101 (5.9%) had indeterminate ILA on baseline CTs. ILD was diagnosed in 10 (24.4%) of 41 with ILA on baseline CT with a mean time from baseline CT to diagnosis of 4.47 ± 2.72 years. On multivariable modeling, the presence of ILA remained a significant predictor of death, HR 3.87 (2.07, 7.21; p < 0.001) when adjusted for age, sex, BMI, pack years and active smoking, but not of lung cancer and all-cause hospital admission. Approximately 50% with baseline ILA had progression on the longitudinal scan.

CONCLUSIONS

ILA identified on baseline lung cancer screening exams are associated with all-cause mortality. In addition, a significant proportion of patients with ILA are subsequently diagnosed with ILD and have CT progression on longitudinal scans.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov; No.: NCT04503044.

Diagnostic and prognostic biomarkers for progressive fibrosing interstitial lung disease

No biomarkers have been identified in bronchoalveolar lavage fluid (BALF) for predicting fibrosis progression or prognosis in progressive fibrosing interstitial lung disease (PF-ILD). We investigated BALF biomarkers for PF-ILD diagnosis and prognosis assessment. Overall, 120 patients with interstitial pneumonia who could be diagnosed with PF-ILD or non PF-ILD were enrolled in this retrospective study. PF-ILD was diagnosed according to Cottin's definition. All patients underwent bronchoscopy and BALF collection. We evaluated blood and BALF parameters, high-resolution computed tomography (HRCT) patterns, and spirometry data to identify factors influencing PF-ILD diagnosis and prognosis. On univariate logistic analysis, age, sex, the BALF white blood cell fraction (neutrophil, lymphocyte, eosinophil, and neutrophil-to-lymphocyte ratio), BALF flow cytometric analysis (CD8), and an idiopathic pulmonary fibrosis/usual interstitial pneumonia pattern on HRCT were correlated with PF-ILD diagnosis. Multivariate logistic regression analysis revealed that sex (male), age (cut-off 62 years, area under the curve [AUC] 0.67; sensitivity 0.80; specificity 0.47), white blood cell fraction in BALF (NLR, neutrophil, and lymphocyte), and CD8 in BALF (cut-off 34.2; AUC 0.66; sensitivity, 0.74; specificity, 0.62) were independent diagnostic predictors for PF-ILD. In BALF, the NLR (cut-off 8.70, AUC 0.62; sensitivity 0.62; specificity 0.70), neutrophil count (cut-off 3.0, AUC 0.59; sensitivity 0.57; specificity 0.63), and lymphocyte count (cut-off 42.0, AUC 0.63; sensitivity 0.77; specificity 0.53) were independent diagnostic predictors. In PF-ILD patients (n = 77), lactate dehydrogenase (cut-off 275, AUC 0.69; sensitivity 0.57; specificity 0.78), Krebs von den Lungen-6 (cut-off 1,140, AUC 0.74; sensitivity 0.71; specificity 0.76), baseline forced vital capacity (FVC) (cut-off 1.75 L, AUC 0.71; sensitivity, 0.93; specificity, 0.46), and BALF neutrophil ratio (cut-off 6.0, AUC 0.72; sensitivity 0.79; specificity 0.80) correlated with death within 3 years. The BALF cellular ratio, particularly the neutrophil ratio, correlated with the diagnosis and prognosis of PF-ILD. These findings may be useful in the management of patients with interstitial pneumonia.

Developing a self-management package for pulmonary fibrosis: an international Delphi study

Rationale

Self-management is considered as an important part of disease management for people with pulmonary fibrosis (PF), but there is a lack of consensus regarding what components should be included. This study aimed to attain consensus from experts in PF and people living with the disease on the essential components and format of a PF self-management package.

Methods

A two-round Delphi process was conducted. In each round, a panel of experts completed an online survey to rate a range of components, formats and delivery methods, followed by an online patient focus group to integrate patient perspectives. Consensus was defined a priori.

Results

45 experts participated in Round 1 and 51 in Round 2. Both focus groups included six people with PF. 12 components were considered essential for self-management in PF: 1) understanding treatment options; 2) understanding and accessing clinical trials; 3) managing medications; 4) role of oxygen therapy; 5) role and importance of pulmonary rehabilitation and regular physical activity; 6) managing shortness of breath; 7) managing fatigue; 8) managing mood; 9) managing comorbidities; 10) smoking cessation advice and support; 11) accessing community support; and 12) how to communicate with others when living with PF. Both groups agreed that self-management in PF required individualisation, goal setting and feedback.

Conclusion

This study identified 12 essential components and highlighted individualisation, goal setting and feedback in self-management of PF. The findings provide a basis for the development of PF self-management interventions.