Contribution of collagen XIII to lung function and development of pulmonary fibrosis

BACKGROUND

Collagen XIII is a transmembrane collagen associated with neuromuscular junction development, and in humans its deficiency results in congenital myasthenic syndrome type 19 (CMS19), which leads to breathing difficulties. CMS19 patients usually have restricted lung capacity and one patient developed chronic lung disease. In single-cell RNA sequencing studies, collagen XIII has been identified as a marker for pulmonary lipofibroblasts, which have been implicated in the resolution of pulmonary fibrosis.

METHODS

We investigated the location and function of collagen XIII in the lung to understand the origin of pulmonary symptoms in human CMS19 patients. Additionally, we performed immunostainings on idiopathic pulmonary fibrosis (IPF) samples (N=5) and both normal and fibrotic mouse lung. To study whether the lack of collagen XIII predisposes to restrictive lung disease, we exposed Col13a1-modified mice to bleomycin-induced pulmonary fibrosis.

RESULTS

Apparently normal alveolar septum sections of IPF patients' lungs stained faintly for collagen XIII, and its expression was pinpointed to the septal fibroblasts in the mouse lung. Lung capacity was increased in mice lacking collagen XIII by over 10%. In IPF samples, collagen XIII was expressed by basal epithelial cells, hyperplastic alveolar epithelial cells and stromal cells in fibrotic areas, but the development of pulmonary fibrosis was unaffected in collagen XIII-deficient mice.

CONCLUSIONS

Changes in mouse lung function appear to represent a myasthenic manifestation of collagen XIII deficiency. We suggest that respiratory muscle myasthenia is the primary cause of the breathing problems suffered by CMS19 patients in addition to skeletal deformities. Induction of collagen XIII expression in the IPF patients' lungs warrants further studies to reveal collagen XIII-dependent disease mechanisms.

Variation in information needs of patients with interstitial lung disease and their family caregivers according to long-term oxygen therapy: a descriptive study

BACKGROUND

The information needs of patients and their families regarding interstitial lung disease (ILD) have yet to be studied in detail, and few reports have examined the differences in information needs according to patient status. This study aimed to determine whether there are differences in information needs between outpatients with ILD and their family caregivers and whether these differences depend on long-term oxygen therapy use.

METHODS

Patients with fibrotic ILDs and their families who visited Kyoto University Hospital between February 2020 and March 2022 were recruited for this descriptive study. Fibrotic ILDs included idiopathic pulmonary fibrosis (IPF), other idiopathic interstitial pneumonias (IIPs) than IPF, connective tissue disease-associated ILD (CTD-ILD), and fibrotic hypersensitivity pneumonia. Data were obtained from electronic patient records and questionnaires. Descriptive data analyses were performed.

RESULTS

Sixty-five patients and their family caregivers were analyzed. Twenty-seven (41.5%) patients had IIPs (IPF 9 and other IIPs 18), 34 (52.3%) had CTD-ILD, and 4 (6.2%) had fibrotic hypersensitivity pneumonia. The most common relationship between the patient and their family was a spouse (67.7%), with 80% living together. The primary information needs among patients and their family caregivers were common up to the third rank but differed from the rest. Patients were interested in "when and where to contact health care providers" and "end-of-life care and advanced directives," while family caregivers were interested in "diet and nutrition" and "care and support at home." Patients with long-term oxygen therapy had higher needs for "end-of-life care and advanced directives" and "how to manage breathlessness, cough, and fatigue," while the needs for "drugs for ILD" and "acute exacerbation of ILD" were relatively low. Family caregivers were interested in "diet and nutrition" in the long-term oxygen therapy group and "acute exacerbation of ILD" in the no long-term oxygen therapy group.

CONCLUSIONS

This study found that the information needs of patients and their family caregivers were not the same and that the aspect of information needs differed by long-term oxygen therapy status. Healthcare providers should consider the position of the recipient of information, the appropriate time based on the patient's condition, and the necessary information.

Burden of Disease and Productivity Loss in the European Economic Area in Patients Affected by Fibrosing Interstitial Lung Disease

INTRODUCTION

Progression of fibrosis in interstitial lung diseases (ILD) has been associated with poor prognosis, lower quality of life for patients and caregivers, and higher healthcare costs. This study estimated the burden of disease and productivity loss of progressively fibrosing ILD, focusing on progressive pulmonary fibrosis other than idiopathic pulmonary fibrosis (non-IPF PPF) and systemic sclerosis-associated ILD (SSc-ILD) in the European Economic Area (EEA).

METHODS

An economic model was built to estimate the clinical burden of SSc-ILD and non-IPF PPF. The model was based on published data on disease prevalence and disease burden (in terms of comorbidities, exacerbations, and deaths) as well as on productivity loss (in terms of sick days, early retirement, permanent disability, and job loss). Aggregate income loss was obtained by multiplying productivity loss by the median daily income in each country/area of investigation. A sensitivity analysis was performed to test the impact of the variability of the model assumptions.

RESULTS

In the whole EEA, a total of 86,794 and 13,221 individuals were estimated to be affected by non-IPF PPF and SSc-ILD, respectively. Estimated annual sick days associated with the diseases were 3,952,604 and 672,172, early retirements were 23,174 and 5341, permanently disabled patients were 41,748 and 4037, and job losses were 19,789 and 2617 for non-IPF PPF and SSc-ILD, respectively. Annual exacerbations were estimated to be 22,401-31,181 and 1259-1753, while deaths were 5791-6171 and 572-638 in non-IPF PPF and SSc-ILD, respectively. The estimated annual aggregate income loss in EEA, accounting for losses due to annual sick days, early retirements, and permanently disabled patients, was €1433 million and €220 million in non-IPF PPF and SSc-ILD, respectively. The productivity loss due to job losses was €194 million and €26 million in non-IPF PPF and SSc-ILD, respectively. The main driver of aggregate income loss variability was the prevalence.

CONCLUSION

The impact of non-IPF PPF and SSc-ILD on society is definitely non-negligible. Actions to reduce the burden on our societies are highly needed.

The impact of nintedanib and pirfenidone on lung function and survival in patients with idiopathic pulmonary fibrosis in real-life setting

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic, fibrosing interstitial pneumonia of unknown cause that is associated with radiological and/or histological features of usual interstitial pneumonia (UIP). A mean survival of 2-5 years was reported previously to the advent of antifibrotics. According to clinical trials, nintedanib and pirfenidone induce a significant delay in functional decline, with a favorable impact on survival.

METHODS

A real-life retrospective and longitudinal study was conducted to assess the efficacy and tolerability of antifibrotics in IPF patients, between January 2014 and December 2020. Two groups (under nintedanib or pirfenidone) were analyzed at diagnosis through their clinical features and radiological patterns. Lung function was assessed at diagnosis (time 0) and after 6, 12 and 24 months of treatment. We also compared this antifibrotic cohort with an older naïve antifibrotic cohort, mainly treated with immunosuppressive drugs and/or N- acetylcysteine. Survival was analyzed and prognostic features were also studied. Statistical analysis was performed with IBM® SPSS®.

RESULTS

A cohort of 108 patients under antifibrotics (nintedanib n = 54; pirfenidone n = 54) was assessed. Lung function analysis showed an overall stabilization in FVC and DLCO mean predicted percentages at 6, 12 and 24 months of treatment. The mean decline in FVC and DLCO, at 12 months, was -40.95 ± 438.26 mL and -0.626 ± 1.31 mL/min/mmHg, respectively. However, during this period, 34.2% of the patients died mostly due to acute exacerbation associated with a poorer lung function at diagnosis. Mean survival in the naïve antifibrotic cohort was significantly lower than in the antifibrotic cohort (39.9 months versus 58.2 months; p < 0.005). Regarding lung function evolution and survival, we found no differences between definitive or probable UIP radiological patterns, both on patients under nintedanib and pirfenidone (p = 0.656).

CONCLUSIONS

In this real-life observational study, the positive impact of antifibrotic therapy on the IPF clinical course and on survival was corroborated. Regarding efficacy, there was no difference between patients taking nintedanib or pirfenidone. The need for an early treatment was also demonstrated, since a worse outcome is clearly associated with lower lung volumes and lower diffusing capacity at diagnosis.

Efficacy of N-acetylcysteine plus pirfenidone in the treatment of idiopathic pulmonary fibrosis: a systematic review and meta-analysis

BACKGROUND

Numerous studies have demonstrated the potential of pirfenidone to enhance the prognosis of patients afflicted with idiopathic pulmonary fibrosis (IPF). Although N-acetylcysteine (NAC) is utilized as an antioxidant in IPF treatment, the combination of NAC and pirfenidone has produced inconsistent outcomes in certain studies. To assess the clinical effectiveness and safety of NAC plus pirfenidone (designated as the treatment group) versus pirfenidone monotherapy (designated as the control group), we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs).

METHODS

RCTs of NAC plus pirfenidone were reviewed searching from databases and networks of unpublished and published studies in any language. Using pair-wise meta-analysis, changes in pulmonary function test (PFT) parameters and safety were evaluated.

RESULTS

Two independent reviewers selected and obtained data from 5 RCTs (n = 398), comprising 1 study from Japan, 1 from Europe, and 3 from China. NAS plus pirfenidone as compared to pirfenidone monotherapy for IPF may not reduce the incidence of skin effects(RR 1.26 [95%CI 0.64 to 2.45]) and mortality(RR 0.35 [95%CI 0.07 to 1.68])(both moderate certainty). NAS plus pirfenidone as compared to pirfenidone monotherapy for IPF may not reduce the incidence of at least one side effects(RR 1.00 [95%CI 0.84 to 1.19]; low certainty),severe side effects(RR 0.67 [95%CI 0.30 to 1.47]; low certainty) and gastrointestinal effects(RR 0.67 [95%CI 0.41 to 1.09]; low certainty) with possibly no effect in Δ%DLco(SMD -0.17 [95%CI -0.15 to 0.48]; low certainty). Meanwhile, the effect of NAS plus pirfenidone as compared to pirfenidone monotherapy on ΔFVC(SMD 0.18 [95%CI -0.68 to 1.05]), Δ%FVC(SMD -2.62 [95%CI -5.82 to 0.59]) and Δ6MWT(SMD -0.35 [95%CI -0.98 to 0.28]) is uncertain(extremely low certainty).

CONCLUSION

Moderate certainty evidence suggests that NAS plus pirfenidone, compared to pirfenidone monotherapy for IPF, does not reduce the incidence of skin effects and mortality.

Peptidylarginine deiminase 2 citrullinates MZB1 and promotes the secretion of IgM and IgA

Introduction

MZB1 is an endoplasmic reticulum residential protein preferentially expressed in plasma cells, marginal zone and B1 B cells. Recent studies on murine B cells show that it interacts with the tail piece of IgM and IgA heavy chain and promotes the secretion of these two classes of immunoglobulin. However, its role in primary human B cells has yet to be determined and how its function is regulated is still unknown. The conversion of peptidylarginine to peptidylcitrulline, also known as citrullination, by peptidylarginine deiminases (PADs) can critically influence the function of proteins in immune cells, such as neutrophils and T cells; however, the role of PADs in B cells remains to be elucidated.

Method

An unbiased analysis of human lung citrullinome was conducted to identify citrullinated proteins that are enriched in several chronic lung diseases, including rheumatoid arthritis-associated interstitial lung disease (RA-ILD), chronic obstructive pulmonary disease, and idiopathic pulmonary fibrosis, compared to healthy controls. Mass spectrometry, site-specific mutagenesis, and western blotting were used to confirm the citrullination of candidate proteins. Their citrullination was suppressed by pharmacological inhibition or genetic ablation of PAD2 and the impact of their citrullination on the function and differentiation of human B cells was examined with enzyme-linked immunosorbent assay, flow cytometry, and co-immunoprecipitation.

Results

Citrullinated MZB1 was preferentially enriched in RA-ILD but not in other chronic lung diseases. MZB1 was a substrate of PAD2 and was citrullinated during the differentiation of human plasmablasts. Ablation or pharmacological inhibition of PAD2 in primary human B cells attenuated the secretion of IgM and IgA but not IgG or the differentiation of IgM or IgA-expressing plasmablasts, recapitulating the effect of ablating MZB1. Furthermore, the physical interaction between endogenous MZB1 and IgM/IgA was attenuated by pharmacological inhibition of PAD2.

Discussion

Our data confirm the function of MZB1 in primary human plasmablasts and suggest that PAD2 promotes IgM/IgA secretion by citrullinating MZB1, thereby contributing to the pathogenesis of rheumatoid arthritis and RA-ILD.

Quantitative interstitial lung disease scores in idiopathic inflammatory myopathies: longitudinal changes and clinical implications

OBJECTIVES

To investigate computer-aided quantitative scores from high-resolution CT (HRCT) images and determine their longitudinal changes and clinical significance in patients with idiopathic inflammatory myopathies (IIMs)-related interstitial lung disease (IIMs-ILD).

METHODS

The clinical data and HRCT images of 80 patients with IIMs who underwent serial HRCT scans at least twice were retrospectively analysed. Quantitative ILD (QILD) scores (%) were calculated as the sum of the extent of lung fibrosis, ground-glass opacity, and honeycombing. The individual time-estimated ΔQILD between two consecutive scans was derived using a linear approximation of yearly changes.

RESULTS

The baseline median QILD (interquartile range) scores in the whole lung were 28.1% (19.1-43.8). The QILD was significantly correlated with forced vital capacity (r = -0.349, P = 0.002) and diffusing capacity for carbon monoxide (r = -0.381, P = 0.001). For ΔQILD between the first two scans, according to the visual ILD subtype, QILD aggravation was more frequent in patients with usual interstitial pneumonia (UIP) than non-UIP (80.0% vs 44.4%, P = 0.013). Multivariable logistic regression analyses identified UIP was significantly related to radiographic ILD progression (ΔQILD >2%, P = 0.015). Patients with higher baseline QILD scores (>28.1%) had a higher risk of lung transplantation or death (P = 0.015). In the analysis of three serial HRCT scans (n = 41), dynamic ΔQILD with four distinct patterns (improving, worsening, convex and concave) was observed.

CONCLUSION

QILD changes in IIMs-ILD were dynamic, and baseline UIP patterns seemed to be related to a longitudinal progression in QILD. These may be potential imaging biomarkers for lung function, changes in ILD severity and prognosis in IIMs-ILD.

Automated airway quantification associates with mortality in idiopathic pulmonary fibrosis

OBJECTIVES

The study examined whether quantified airway metrics associate with mortality in idiopathic pulmonary fibrosis (IPF).

METHODS

In an observational cohort study (n = 90) of IPF patients from Ege University Hospital, an airway analysis tool AirQuant calculated median airway intersegmental tapering and segmental tortuosity across the 2nd to 6th airway generations. Intersegmental tapering measures the difference in median diameter between adjacent airway segments. Tortuosity evaluates the ratio of measured segmental length against direct end-to-end segmental length. Univariable linear regression analyses examined relationships between AirQuant variables, clinical variables, and lung function tests. Univariable and multivariable Cox proportional hazards models estimated mortality risk with the latter adjusted for patient age, gender, smoking status, antifibrotic use, CT usual interstitial pneumonia (UIP) pattern, and either forced vital capacity (FVC) or diffusion capacity of carbon monoxide (DLco) if obtained within 3 months of the CT.

RESULTS

No significant collinearity existed between AirQuant variables and clinical or functional variables. On univariable Cox analyses, male gender, smoking history, no antifibrotic use, reduced DLco, reduced intersegmental tapering, and increased segmental tortuosity associated with increased risk of death. On multivariable Cox analyses (adjusted using FVC), intersegmental tapering (hazard ratio (HR) = 0.75, 95% CI = 0.66-0.85, p < 0.001) and segmental tortuosity (HR = 1.74, 95% CI = 1.22-2.47, p = 0.002) independently associated with mortality. Results were maintained with adjustment using DLco.

CONCLUSIONS

AirQuant generated measures of intersegmental tapering and segmental tortuosity independently associate with mortality in IPF patients. Abnormalities in proximal airway generations, which are not typically considered to be abnormal in IPF, have prognostic value.

CLINICAL RELEVANCE STATEMENT

Quantitative measurements of intersegmental tapering and segmental tortuosity, in proximal (second to sixth) generation airway segments, independently associate with mortality in IPF. Automated airway analysis can estimate disease severity, which in IPF is not restricted to the distal airway tree.

KEY POINTS

• AirQuant generates measures of intersegmental tapering and segmental tortuosity. • Automated airway quantification associates with mortality in IPF independent of established measures of disease severity. • Automated airway analysis could be used to refine patient selection for therapeutic trials in IPF.

The potential role of artificial intelligence in the clinical practice of interstitial lung disease

Artificial intelligence (AI) is being widely applied in the field of medicine, in areas such as drug discovery, diagnostic support, and assistance with medical practice. Among these, medical imaging is an area where AI is expected to make a significant contribution. In Japan, as of November 2022, 23 AI medical devices have received regulatory approval; all these devices are related to image analysis. In interstitial lung diseases, technologies have been developed that use AI to analyze high-resolution computed tomography and pathological images, and gene expression patterns in tissue taken from transbronchial lung biopsies to assist in the diagnosis of idiopathic pulmonary fibrosis. Some of these technologies are already being used in clinical practice in the United States. AI is expected to reduce the burden on physicians, improve reproducibility, and advance personalized medicine. Obtaining sufficient data for diseases with a small number of patients is difficult. Additionally, certain issues must be addressed in order for AI to be applied in healthcare. These issues include taking responsibility for the AI results output, updating software after the launch of technology, and adapting to new imaging technologies. Establishing research infrastructures such as large-scale databases and common platforms is important for the development of AI technology: their use requires an understanding of the characteristics and limitations of the systems. CLINICAL TRIAL REGISTRATION: Not applicable.

Analysis of tissue lipidomics and computed tomography pulmonary fat attenuation volume (CTPFAV ) in idiopathic pulmonary fibrosis

BACKGROUND AND OBJECTIVE

There is increasing interest in the role of lipids in processes that modulate lung fibrosis with evidence of lipid deposition in idiopathic pulmonary fibrosis (IPF) histological specimens. The aim of this study was to identify measurable markers of pulmonary lipid that may have utility as IPF biomarkers.

STUDY DESIGN AND METHODS

IPF and control lung biopsy specimens were analysed using a unbiased lipidomic approach. Pulmonary fat attenuation volume (PFAV) was assessed on chest CT images (CTPFAV ) with 3D semi-automated lung density software. Aerated lung was semi-automatically segmented and CTPFAV calculated using a Hounsfield-unit (-40 to -200HU) threshold range expressed as a percentage of total lung volume. CTPFAV was compared to pulmonary function, serum lipids and qualitative CT fibrosis scores.

RESULTS

There was a significant increase in total lipid content on histological analysis of IPF lung tissue (23.16 nmol/mg) compared to controls (18.66 mol/mg, p = 0.0317). The median CTPFAV in IPF was higher than controls (1.34% vs. 0.72%, p < 0.001) and CTPFAV correlated significantly with DLCO% predicted (R2  = 0.356, p < 0.0001) and FVC% predicted (R2  = 0.407, p < 0.0001) in patients with IPF. CTPFAV correlated with CT features of fibrosis; higher CTPFAV was associated with >10% reticulation (1.6% vs. 0.94%, p = 0.0017) and >10% honeycombing (1.87% vs. 1.12%, p = 0.0003). CTPFAV showed no correlation with serum lipids.

CONCLUSION

CTPFAV is an easily quantifiable non-invasive measure of pulmonary lipids. In this pilot study, CTPFAV correlates with pulmonary function and radiological features of IPF and could function as a potential biomarker for IPF disease severity assessment.

Telomere length and immunosuppression in non-idiopathic pulmonary fibrosis interstitial lung disease

BACKGROUND

Studies suggest a harmful pharmacogenomic interaction exists between short leukocyte telomere length (LTL) and immunosuppressants in idiopathic pulmonary fibrosis (IPF). It remains unknown if a similar interaction exists in non-IPF interstitial lung disease (ILD).

METHODS

A retrospective, multicentre cohort analysis was performed in fibrotic hypersensitivity pneumonitis (fHP), unclassifiable ILD (uILD) and connective tissue disease (CTD)-ILD patients from five centres. LTL was measured by quantitative PCR for discovery and replication cohorts and expressed as age-adjusted percentiles of normal. Inverse probability of treatment weights based on propensity scores were used to assess the association between mycophenolate or azathioprine exposure and age-adjusted LTL on 2-year transplant-free survival using weighted Cox proportional hazards regression incorporating time-dependent immunosuppressant exposure.

RESULTS

The discovery and replication cohorts included 613 and 325 patients, respectively. In total, 40% of patients were exposed to immunosuppression and 22% had LTL <10th percentile of normal. fHP and uILD patients with LTL <10th percentile experienced reduced survival when exposed to either mycophenolate or azathioprine in the discovery cohort (mortality hazard ratio (HR) 4.97, 95% CI 2.26-10.92; p<0.001) and replication cohort (mortality HR 4.90, 95% CI 1.74-13.77; p=0.003). Immunosuppressant exposure was not associated with differential survival in patients with LTL ≥10th percentile. There was a significant interaction between LTL <10th percentile and immunosuppressant exposure (discovery pinteraction=0.013; replication pinteraction=0.011). Low event rate and prevalence of LTL <10th percentile precluded subgroup analyses for CTD-ILD.

CONCLUSION

Similar to IPF, fHP and uILD patients with age-adjusted LTL <10th percentile may experience reduced survival when exposed to immunosuppression.

Causal relationship between lung diseases and risk of esophageal cancer: insights from Mendelian randomization

BACKGROUND

An increasing number of cohort studies have indicated a correlation between lung diseases and esophageal cancer, but the exact causal relationship has not been definitively established. Therefore, the objective of this study is to assess the causal relationship between lung diseases and esophageal cancer.

METHODS

Single-nucleotide polymorphisms (SNPs) related to lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), lung cancer, and idiopathic pulmonary fibrosis (IPF), along with outcomes data on esophageal cancer, were extracted from public genome-wide association studies (GWAS). A two-sample Mendelian randomization (MR) analysis was then performed using publicly available GWAS data to investigate the potential causal relationship. The effect estimates were primarily calculated using the fixed-effects inverse-variance-weighted method.

RESULTS

Totally, 81 SNPs related to asthma among 218,792 participants in GWAS. Based on the primary causal effects model using MR analyses with the inverse variance weighted (IVW) method, asthma was demonstrated a significantly related to the risk of esophageal cancer (OR 1.0006; 95% CI 1.0003-1.0010, p = 0.001), while COPD (OR 1.0306; 95% CI 0.9504-1.1176, p = 0.466), lung cancer (OR 1.0003, 95% CI 0.9998-1.0008, p = 0.305), as well as IPF (OR 0.9999, 95% CI 0.9998-1.0000, p = 0.147), showed no significant correlation with esophageal cancer.

CONCLUSIONS

The two-sample MR analysis conducted in this study revealed a positive causal relationship between asthma and esophageal cancer. In contrast, esophageal cancer demonstrated no significant correlation with COPD, lung cancer, or IPF. Further large-sample prospective studies are needed to validate these findings and to provide appropriate recommendations regarding esophageal cancer screening among patients with asthma.

Nailfold capillaroscopy findings of interstitial pneumonia with autoimmune features

BACKGROUND/AIMS

We evaluated nailfold capillaroscopy (NFC) of interstitial pneumonia with autoimmune features (IPAF) and compared it with that of patients with connective tissue disease-interstitial lung disease (CTD-ILD) and idiopathic interstitial pneumonia (IIP).

METHODS

Patients with newly diagnosed as ILD were evaluated using NFC. Baseline demographic, clinical, serological, and high-resolution CT findings were collected. NFC was semi-quantitatively scored with six domains ranging from 0 to 18. In addition, the overall patterns (scleroderma/non-scleroderma patterns) were determined.

RESULTS

A total of 81 patients (31 with CTD-ILD, 18 with IPAF, and 32 with IIP) were included. The non-specific interstitial pneumonia pattern was the most common ILD pattern in the CTD-ILD and IPAF groups, whereas the usual interstitial pneumonia pattern was the most common in the IIP group. The semi-quantitative score of the CTD-ILD group was higher than that of the IPAF or IIP groups (5.8 vs 4.2 vs 3.0, p < 0.001, respectively). Giant capillaries and haemorrhages were more frequently present in the CTD-ILD and IPAF groups than in the IIP group. A scleroderma pattern was present in 27.8% of the IPAF group, whereas none of the IIP patients showed a scleroderma pattern.

CONCLUSION

NFC findings may be useful in classifying patients with ILD into CTD-ILD/IPAF/IIP.

Imaging Features of Idiopathic Interstitial Lung Diseases

Idiopathic interstitial pneumonias (IIPs) are a group of diffuse parenchymal lung diseases of unclear etiology and are distinguished from diffuse parenchymal lung diseases of known cause, such as connective tissue disease-related interstitial lung diseases or hypersensitivity pneumonitis by history, physical exam, imaging, serologic testing, and, when necessary, histopathology. The 2013 American Thoracic Society (ATS)/European Respiratory Society (ERS) guidelines are the most widely accepted classification of IIPs and include the following diagnoses: idiopathic pulmonary fibrosis, idiopathic nonspecific interstitial pneumonia, cryptogenic organizing pneumonia, acute interstitial pneumonia, idiopathic lymphocytic interstitial pneumonia, idiopathic pleuro-parenchymal fibroelastosis, respiratory bronchiolitis-interstitial lung disease, and desquamative interstitial pneumonia. The gold standard for diagnosis of IIP involves multidisciplinary discussion among pulmonologists, radiologists, and pathologists. The focus of this review will be to discuss the imaging features of the most common IIPs and the role of multidisciplinary discussion as the gold standard for diagnosis.

Missing out on effective care in idiopathic pulmonary fibrosis: Racial inequality in access to anti-fibrotic therapy

See related article

Combination of BAL and Computed Tomography Differentiates Progressive and Non-progressive Fibrotic Lung Diseases

Rationale: Identifying patients with pulmonary fibrosis (PF) at risk of progression can guide management. Objectives: To explore the utility of combining baseline BAL and computed tomography (CT) in differentiating progressive and nonprogressive PF. Methods: The derivation cohort consisted of incident cases of PF for which BAL was performed as part of a diagnostic workup. A validation cohort was prospectively recruited with identical inclusion criteria. Baseline thoracic CT scans were scored for the extent of fibrosis and usual interstitial pneumonia (UIP) pattern. The BAL lymphocyte proportion was recorded. Annualized FVC decrease of >10% or death within 1 year was used to define disease progression. Multivariable logistic regression identified the determinants of the outcome. The optimum binary thresholds (maximal Wilcoxon rank statistic) at which the extent of fibrosis on CT and the BAL lymphocyte proportion could distinguish disease progression were identified. Measurements and Main Results: BAL lymphocyte proportion, UIP pattern, and fibrosis extent were significantly and independently associated with disease progression in the derivation cohort (n = 240). Binary thresholds for increased BAL lymphocyte proportion and extensive fibrosis were identified as 25% and 20%, respectively. An increased BAL lymphocyte proportion was rare in patients with a UIP pattern (8 of 135; 5.9%) or with extensive fibrosis (7 of 144; 4.9%). In the validation cohort (n = 290), an increased BAL lymphocyte proportion was associated with a significantly lower probability of disease progression in patients with nonextensive fibrosis or a non-UIP pattern. Conclusions: BAL lymphocytosis is rare in patients with extensive fibrosis or a UIP pattern on CT. In patients without a UIP pattern or with limited fibrosis, a BAL lymphocyte proportion of ⩾25% was associated with a lower likelihood of progression.

Influence of pulmonary rehabilitation on symptoms of anxiety and depression in interstitial lung disease: A systematic review of randomized controlled trials

BACKGROUND

Interstitial lung diseases (ILDs) cause fibrosis of lung parenchyma, leading to impaired quality of life, dyspnea, and functional decline. Individuals with ILD experience a high prevalence of anxiety and depression. Recent research has demonstrated pulmonary rehabilitation (PR) alleviates symptoms of anxiety and depression in those with COPD.

RESEARCH QUESTION

What is the influence of PR on symptoms of anxiety and depression in individuals with ILD?

STUDY DESIGN

We conducted a PRISMA-2020-compliant systematic review of randomized controlled trials (RCTs) investigating PR's effect on anxiety and depression in patients with ILD. We searched MEDLINE, EMBASE, Cochrane, and PsycINFO from inception until April 3, 2023. A narrative synthesis was conducted where a quantitative approach was not feasible.

RESULTS

Five RCTs (n = 281) were included. Idiopathic pulmonary fibrosis (IPF) was the most common type of ILD (k = 3). One study reported clinically-significant improvements in symptoms of anxiety among patients with IPF, and two studies for symptoms of depression among patients with sarcoidosis. Dropout rates were similar between intervention and control groups. All studies were at a high risk of bias.

INTERPRETATION

Pulmonary rehabilitation is not detrimental to anxiety or depression for patients with ILD, and may improve symptoms of anxiety in IPF and depression in sarcoidosis. However, no conclusion can be drawn from available evidence, which is limited by heterogeneous populations/interventions, sample sizes and unexpectedly low prevalences of clinically-significant anxiety or depression. Further adequately powered RCTs that focus on anxiety and depressive symptoms as primary outcomes are needed.

Physiological effects of lung-protective ventilation in patients with lung fibrosis and usual interstitial pneumonia pattern versus primary ARDS: a matched-control study

BACKGROUND

Although patients with interstitial pneumonia pattern (ILD-UIP) and acute exacerbation (AE) leading to severe acute respiratory failure may require invasive mechanical ventilation (MV), physiological data on lung mechanics during MV are lacking. We aimed at describing the physiological effect of lung-protective ventilation in patients with AE-ILD-UIP compared with primary ARDS.

METHODS

Partitioned lung and chest wall mechanics were assessed in a series of AE-ILD-UIP patients matched 1:1 with primary ARDS as controls (based on BMI and PaO2/FiO2 ratio). Three PEEP levels (zero = ZEEP, 4-8 cmH2O = PEEPLOW, and titrated to achieve positive end-expiratory transpulmonary pressure PL,EE = PEEPTITRATED) were used for measurements.

RESULTS

Ten AE-ILD-UIP patients and 10 matched ARDS were included. In AE-ILD-UIP median PL,EE at ZEEP was - 4.3 [- 7.6- - 2.3] cmH2O and lung elastance (EL) 44 [40-51] cmH2O/L. At PEEPLOW, PL,EE remained negative and EL did not change (p = 0.995) versus ZEEP. At PEEPTITRATED, PL,EE increased to 0.8 [0.3-1.5] cmH2O and EL to 49 [43-59] (p = 0.004 and p < 0.001 compared to ZEEP and PEEPLOW, respectively). ΔPL decreased at PEEPLOW (p = 0.018) and increased at PEEPTITRATED (p = 0.003). In matched ARDS control PEEP titration to obtain a positive PL,EE did not result in significant changes in EL and ΔPL.

CONCLUSIONS

In mechanically ventilated AE-ILD-UIP patients, differently than in patients with primary ARDS, PEEP titrated to obtain a positive PL,EE significantly worsened lung mechanics.

Risk factor analysis of the development of severe radiation pneumonitis in patients with non-small cell lung cancer treated with curative radiotherapy, with focus on underlying pulmonary disease

BACKGROUND

We aim to identify the multifaceted risk factors that can affect the development of severe radiation pneumonitis (RP) in patients with non-small cell lung cancer (NSCLC) treated with curative high-dose radiotherapy with or without concurrent chemotherapy.

METHODS

We retrospectively reviewed the medical records of 175 patients with stage-I-III NSCLC treated with curative thoracic X-ray radiotherapy at the Korea University Guro Hospital between June 2019 and June 2022. Treatment-related complications were evaluated using the Common Terminology Criteria for Adverse Events (version 4.03).

RESULTS

The median follow-up duration was 15 months (range: 3-47 months). Idiopathic pulmonary fibrosis (IPF) as an underlying lung disease (P < 0.001) and clinical stage, regarded as the concurrent use of chemotherapy (P = 0.009), were associated with a high rate of severe RP. In multivariate analyses adjusting confounding variables, the presence of IPF as an underlying disease was significantly associated with severe RP (odds ratio [95% confidence interval] = 48.4 [9.09-347]; P < 0.001). In a subgroup analysis of stage-I-II NSCLC, the incidence of severe RP in the control, chronic obstructive pulmonary disease (COPD), and IPF groups was 3.2%, 4.3%, and 42.9%, respectively (P < 0.001). The incidence of severe RP was 15.2%, 10.7%, and 75.0% in the control, COPD, and IPF groups, respectively (P < 0.001) in the stage-III NSCLC group.

CONCLUSIONS

This study revealed that IPF as an underlying lung disease and the concurrent use of chemotherapy are associated with a high rate of severe RP. In contrast, COPD did not increase the risk of pulmonary toxicity after receiving curative high-dose radiotherapy.

Outcomes and prognosis of progressive pulmonary fibrosis in patients with antineutrophil cytoplasmic antibody-positive interstitial lung disease

Approximately one-third of fibrosing interstitial lung diseases exhibit progressive pulmonary fibrosis (PPF), a clinicopathological condition distinct yet resembling idiopathic pulmonary fibrosis (IPF). PPF in ANCA-positive ILD (ANCA-ILD) is poorly documented. To clarify incidence, predictors of PPF in ANCA-ILD, and their prognostic impact, 56 patients with ANCA-ILD were followed for ≥ 1 year (April 2004 to April 2021). PPF was defined per ATS/ERS/JRS/ALAT PPF 2022 guideline. We compared PPF and non-PPF in 38 patients with pulmonary function tests and ≥ 1 year follow up. ANCA-ILD (19 male, 19 female; mean age 72 years) comprised 21 patients with microscopic polyangiitis ILD (MPA-ILD) and 17 with ANCA-positive IP without systemic vasculitis (ANCA-IP). PPF occurred in 15/38 (39.5%) overall, and 27% of patients with MPA-ILD and 53% with ANCA-IP. Patient characteristics did not differ between PPF and non-PPF, however, the survival was significantly worse in patients with PPF than those with non-PPF. On multivariate regression analysis, higher age, higher serum SP-D level, and lower baseline %FVC were associated with PPF. In ANCA-ILD, 39.5% of patients demonstrated PPF, which is associated with increased mortality. Predictors of PPF were older age, higher SP-D, and lower baseline %FVC.

Prognostic impact of the cross-sectional area of the erector spinae muscle in patients with pleuroparenchymal fibroelastosis

Pleuroparenchymal fibroelastosis (PPFE) progresses slowly but sometimes relatively quickly, leading to decreased activities of daily living (ADL) and muscle weakness. Skeletal muscle atrophy and muscle weakness in chronic obstructive pulmonary disease (COPD) patients may be caused by cachexia and are associated with reduced ADLs and increased risk of death. However, the association between skeletal muscle mass and the prognosis of PPFE patients remains unknown. We retrospectively analysed the clinical significance of the cross-sectional area of the erector spinae muscle (ESMCSA), a skeletal muscle index, and predictors of mortality within 3 years in PPFE 51 patients, idiopathic pulmonary fibrosis (IPF) 52 patients and COPD 62 patients. PPFE patients had significantly lower ESMCSA than IPF or COPD patients, and lower ESMCSA (< 22.57 cm2) was associated with prognosis within 3 years (log-rank test; p = 0.006), whereas lower body mass index (BMI) showed no association. Multivariate analysis showed that ESMCSA was an independent predictor of mortality within 3 years in PPFE patients (hazard ratio, 0.854; 95% confidence interval: 0.737-0.990, p = 0.036). These results suggest the importance of monitoring ESMCSA in PPFE patients and that assessing ESMCSA in PPFE patients could be a more useful prognostic indicator than BMI.

Bronchial epithelial gene expression and interstitial lung abnormalities

INTRODUCTION

Interstitial lung abnormalities (ILA) often represent early fibrotic changes that can portend a progressive fibrotic phenotype. In particular, the fibrotic subtype of ILA is associated with increased mortality and rapid decline in lung function. Understanding the differential gene expression that occurs in the lungs of participants with fibrotic ILA may provide insight into development of a useful biomarker for early detection and therapeutic targets for progressive pulmonary fibrosis.

METHODS

Measures of ILA and gene expression data were available in 213 participants in the Detection of Early Lung Cancer Among Military Personnel (DECAMP1 and DECAMP2) cohorts. ILA was defined using Fleischner Society guidelines and determined by sequential reading of computed tomography (CT) scans. Primary analysis focused on comparing gene expression in ILA with usual interstitial pneumonia (UIP) pattern with those with no ILA.

RESULTS

ILA was present in 51 (24%) participants, of which 16 (7%) were subtyped as ILA with a UIP pattern. One gene, pro platelet basic protein (PPBP) and seventeen pathways (e.g. TNF-α signalling) were significantly differentially expressed between those with a probable or definite UIP pattern of ILA compared to those without ILA. 16 of these 17 pathways, but no individual gene, met significance when comparing those with ILA to those without ILA.

CONCLUSION

Our study demonstrates that abnormal inflammatory processes are apparent in the bronchial airway gene expression profiles of smokers with and without lung cancer with ILA. Future studies with larger and more diverse populations will be needed to confirm these findings.