Interstitial lung disease: raising the index of suspicion in primary care

Expanding horizons: lung transplantation for non-IPF interstitial lung diseases

OBJECTIVE

Interstitial lung diseases (ILDs) are diverse pulmonary disorders marked by diffuse lung inflammation and fibrosis. The variability in characteristics and treatment approaches complicates diagnosis and management. In advanced cases requiring transplantation, determining indications and selecting suitable candidates presents additional challenges.

METHODS

Of all patients with non-IPF ILD between December 2016 to December 2022 were analyzed retrospectively. Patients were categorized into two groups: transplanted patients and deceased patients on the waiting list. Clinical data and survival outcomes were compared between groups.

RESULTS

Of the 43 patients, 20 underwent lung transplantation while 23 died awaiting transplantation. Waiting list mortality was 53.4%, with median waiting times similar between groups (3 months for transplant patients and 6 months for those on the waiting list). There were no significant differences between groups in age, gender, height, BMI, 6-minute walk test (6MWT), or forced vital capacity (FVC). The prevalence of pulmonary hypertension (PH) was 76.7% in right heart catheterizations, similar in both groups. One single and 19 bilateral lung transplants were performed. Overall, 13 of the 20 patients survived to discharge from the hospital. One-year mortality was 7/20 (35%). The median follow-up was 34 months, with a 1-year conditional survival of 90.9% at 3 years and 70.7% at 5 years.

CONCLUSIONS

This study underscores the importance of further research into non-IPF ILDs. Lung transplantation remains a viable option that can significantly enhance both the quality and longevity of life for patients with advanced ILD.

Levels of Lysozyme and SLPI in Bronchoalveolar Lavage: Exploring Their Role in Interstitial Lung Disease

Interstitial lung diseases (ILDs) are characterized by inflammation or fibrosis of the pulmonary parenchyma. Despite the involvement of immune cells and soluble mediators in pulmonary fibrosis, the influence of antimicrobial peptides (AMPs) remains underexplored. These effector molecules display a range of activities, which include immunomodulation and wound repair. Here, we investigate the role of AMPs in the development of fibrosis in ILD. We compare the concentration of different AMPs and different cytokines in 46 fibrotic (F-ILD) and 17 non-fibrotic (NF-ILD) patients by ELISA and using peripheral blood mononuclear cells from in vitro stimulation in the presence of lysozyme or secretory leukocyte protease inhibitor (SLPI) from 10 healthy donors. We observed that bronchoalveolar lavage (BAL) levels of AMPs were decreased in F-ILD patients (lysozyme: p < 0.001; SLPI: p < 0.001; LL-37: p < 0.001; lactoferrin: p = 0.47) and were negatively correlated with levels of TGF-β (lysozyme: p = 0.02; SLPI: p < 0.001) and IL-17 (lysozyme: p < 0.001; SLPI: p < 0.001). We observed that lysozyme increased the percentage of CD86+ macrophages (p < 0.001) and the production of TNF-α (p < 0.001). We showed that lysozyme and SLPI were associated with clinical parameters (lysozyme: p < 0.001; SLPI: p < 0.001) and disease progression (lysozyme: p < 0.001; SLPI: p = 0.01). These results suggest that AMPs may play an important role in the anti-fibrotic response, regulating the effect of pro-fibrotic cytokines. In addition, levels of lysozyme in BAL may be a potential biomarker to predict the progression in F-ILD patients.

Current Landscape and Future Directions of Patient Education in Adults with Interstitial Lung Disease

Background

Understandable, comprehensive, and accessible educational materials for patients with interstitial lung disease (ILD) are lacking. Patients consistently ask for improved access to evidence-based information about ILD. Nonetheless, few research studies focus directly on developing and evaluating interventions to improve patient knowledge.

Objective

We describe the current landscape of patient education in ILD, identify gaps in current approaches to information delivery, and provide frameworks to address these challenges through novel educational tools.

Methods

A literature review was conducted in collaboration with a medical librarian (M.R.D.) in April 2022 using Ovid MEDLINE (1946-), Embase (1947-), Cochrane Central (1993-), and CINAHL (1961-). Search terms included "interstitial lung disease," "pulmonary fibrosis," "patient education," and "information seeking behavior" (see the data supplement for full search terms). Reference lists from selected articles were used to identify additional studies.

Results

Currently, patient education is commonly combined with exercise regimens in pulmonary rehabilitation programs in which benefits of the educational component alone are unclear. Few studies investigate improving knowledge access and acquisition for patients with ILD and their caregivers regarding self-management, oxygen use, and palliative care plans. Online distribution of health information through social media runs the risk of being unregulated and outdated, although it is an avenue of increasing accessibility.

Conclusion

By expanding access to novel ILD-specific education programs and accounting for social determinants of health that impact healthcare access, patient education has the potential to become more attainable, improving patient-centered outcomes. Further research into optimal development, delivery, and efficacy testing of patient education modalities in ILD is warranted.

Weak to no correlation between quantitative high-resolution computed tomography metrics and lung function change in fibrotic diseases

Background

Identifying systemic sclerosis (SSc) and idiopathic pulmonary fibrosis (IPF) patients at risk of more rapid forced vital capacity (FVC) decline could improve trial design. The purpose of the present study was to explore the prognostic value of quantitative high-resolution computed tomography (HRCT) metrics derived by Imbio lung texture analysis (LTA) tool in predicting FVC slope.

Methods

This retrospective study used data from patients who were not treated with investigational drugs with and without background antifibrotic therapies in tocilizumab phase 3 SSc, lebrikizumab phase 2 IPF, and zinpentraxin alfa phase 2 IPF studies conducted from 2015 to 2021. Controlled HRCT axial volumetric multidetector computed tomography scans were evaluated using the Imbio LTA tool. Associations between HRCT metrics and FVC slope were assessed through the Spearman correlation coefficient and adjusted R2 in a linear regression model adjusted by demographics and baseline clinical characteristics.

Results

A total of 271 SSc and IPF patients were analysed. Correlation coefficients of highest magnitude were observed in the SSc study between the extent of ground glass, normal volume, quantification of interstitial lung disease, reticular pattern, and FVC slope (-0.25, 0.28, -0.28, and -0.33, respectively), while the correlation coefficients observed in IPF studies were in general <0.2. The incremental prognostic value of the baseline HRCT metrics was marginal after adjusting baseline characteristics and was inconsistent across study arms.

Conclusion

Data from the SSc and IPF studies suggested weak to no and inconsistent correlation between quantitative HRCT metrics derived by the Imbio LTA tool and FVC slope in the studied SSc and IPF population.

Assessing feasibility of targeted primary care referrals for patients with clinical suspicion of interstitial lung disease using lung ultrasound: a prospective case finding study. The potential benefits of LUS utilization

BACKGROUND

In Primary Health Care (PHC) many interstitial lung disease (ILD) cases may remain at diagnostic delay, due to their challenging presentation and the limited experience of general practitioners (GPs) in recognizing their early symptoms.

OBJECTIVE

We have designed a feasibility study to investigate early ILD case-finding competency between PHC and tertiary care.

METHODS

A cross-sectional prospective case-finding study was launched at two private health care centers of Heraklion, Crete, Greece, during nine months (2021-2022). After clinical assessment by GP, PHC attenders, who agreed to participate in the study, were referred to the Respiratory Medicine Department, University Hospital of Heraklion, Crete, underwent Lung Ultrasound (LUS) and those with an overall suspicion for ILDs underwent high resolution computed tomography (HRCT) scan. Descriptive statistics and chi-square tests were used. Multiple Poisson regression analysis was performed to explain positive LUS and HRCT decision with selected variables.

RESULTS

One hundred and nine patients out of 183 were finally included (54.1% females; mean age 61, SD: 8.3 years). Thirty-five (32.1%) were current smokers. Overall, two out of ten cases were assessed to need HRCT due to a moderate or high suspicion (19.3%; 95%CI 12.7, 27.4). However, in those who had dyspnea in relation to counterparts, a significantly higher percentage of patients with LUS findings (57.9% vs. 34.0%, p=0.013) was found, as in those who had crackles (100.0% vs. 44.2%, p= 0.005). Detected possible ILD provisional labelling cases were 6, and most importantly, 5 of those cases were considered highly suspicious for further evaluation based on LUS findings.

CONCLUSIONS

This is a feasibility study exploring potentials by combining data of medical history, basic auscultation skills, as crackles detection, and inexpensive and radiation-free imaging technique, such as LUS. Cases of ILD labeling may be hidden within PHC, sometimes, much before any clinical manifestation.

The 1-minute sit-to-stand test to detect desaturation during 6-minute walk test in interstitial lung disease

Although the 6 min walk test (6MWT) is well-established for assessing desaturation in patients with interstitial lung disease (ILD), it cannot be easily performed in primary healthcare settings. This retrospective observational study aimed to evaluate the usefulness of the 1 min sit-to-stand test (1STST) for assessing desaturation during 6MWT in ILD patients with normal resting blood oxygen levels. We included 116 patients, and the pulse oxygen saturation (SpO2) for both methods was analyzed. The SpO2 nadir during the 1STST and 6MWT correlated strongly (ρ = 0.82). The frequency of patients with nadir SpO2 < 90% was consistent for both tests (κ = 0.82). 1STST was superior to diffusing capacity for carbon monoxide in detecting desaturation during the 6MWT. These findings were similarly stratified according to performance status or dyspnea scale. The 1STST can easily measure exertional desaturation in ILD patients with normal resting blood oxygen levels and is an alternative to the 6MWT.

Multidisciplinary Approach to Interstitial Lung Diseases: Nothing Is Better than All of Us Together

Interstitial Lung Diseases (ILDs) are a large family of disorders characterized by inflammation and/or fibrosis of areas of the lung dedicated to gas exchange. In this Special Issue entitled “Clinical and Radiological Features of Interstitial Lung Diseases”, we collected a series of contributions in which a multidisciplinary approach was crucial for the correct diagnostic assessment of ILD. Sharing knowledge between different specialties can significantly improve diagnostic approaches and the management of ILD patients.

Historical database cohort study addressing the clinical patterns prior to idiopathic pulmonary fibrosis (IPF) diagnosis in UK primary care

OBJECTIVE

To explore the clinical pathways, including signs and symptoms, and symptom progression patterns preceding idiopathic pulmonary fibrosis (IPF) diagnosis.

DESIGN AND SETTING

A historical cohort study was conducted using primary care patient records from the Optimum Patient Care Research Database.

PARTICIPANTS

Patients included were at least 30 years, had IPF diagnosis, identified via clinical-coding and free-text records and had a consultation with a chest specialist prior to IPF diagnosis.

OUTCOME MEASURES

The signs and symptoms in the year prior to IPF diagnosis from clinical codes and free-text in primary care electronic records included: cough, dyspnoea, dry cough, weight loss, fatigue/malaise, loss of appetite, crackles and clubbed fingers. The time course of presentations of clinical features and investigations in the years prior to IPF diagnosis were mapped.

RESULTS

Within 462 patients identified, the majority (77.9%) had a respiratory consultation within 365 days prior to the chest specialist visit preceding the IPF diagnosis recorded in their primary care records. The most common symptoms recorded in the 1 year prior to IPF diagnosis were dyspnoea (48.7%) and cough (40.9%); other signs and symptoms were rarely recorded (<5%). The majority of patients with cough (58.0%) and dyspnoea (55.0%) in the 1 year before IPF diagnosis had multiple recordings of the respective symptoms. Both cough and dyspnoea were recorded in 23.4% of patients in the year prior to diagnosis. Consultation rates for cough, dyspnoea and both, but not other signs or symptoms, began to increase 4 to 5 years prior diagnosis, with the sharpest increase in the last year. Cough and dyspnoea were often preceded by a reduction in measured weight over 5 years leading to IPF diagnosis.

CONCLUSION

Prolonged cough and/or progressive dyspnoea, especially if accompanied with weight loss, should signal for a referral to specialist assessment at the earliest opportunity.

Visualisation of interstitial lung disease by molecular imaging of integrin αvβ3 and somatostatin receptor 2

OBJECTIVE

To evaluate integrin αvβ3 (alpha-v-beta-3)-targeted and somatostatin receptor 2 (SSTR2)-targeted nuclear imaging for the visualisation of interstitial lung disease (ILD).

METHODS

The pulmonary expression of integrin αvβ3 and SSTR2 was analysed in patients with different forms of ILD as well as in bleomycin (BLM)-treated mice and respective controls using immunohistochemistry. Single photon emission CT/CT (SPECT/CT) was performed on days 3, 7 and 14 after BLM instillation using the integrin αvβ3-targeting ¹⁷⁷Lu-DOTA-RGD and the SSTR2-targeting ¹⁷⁷Lu-DOTA-NOC radiotracer. The specific pulmonary accumulation of the radiotracers over time was assessed by in vivo and ex vivo SPECT/CT scans and by biodistribution studies.

RESULTS

Expression of integrin αvβ3 and SSTR2 was substantially increased in human ILD regardless of the subtype. Similarly, in lungs of BLM-challenged mice, but not of controls, both imaging targets were stage-specifically overexpressed. While integrin αvβ3 was most abundantly upregulated on day 7, the inflammatory stage of BLM-induced lung fibrosis, SSTR2 expression peaked on day 14, the established fibrotic stage. In agreement with the findings on tissue level, targeted nuclear imaging using SPECT/CT specifically detected both imaging targets ex vivo and in vivo, and thus visualised different stages of experimental ILD.

CONCLUSION

Our preclinical proof-of-concept study suggests that specific visualisation of molecular processes in ILD by targeted nuclear imaging is feasible. If transferred into clinics, where imaging is considered an integral part of patients' management, the additional information derived from specific imaging tools could represent a first step towards precision medicine in ILD.

Downregulation of microRNA‑30a in bronchoalveolar lavage fluid from idiopathic pulmonary fibrosis patients

MicroRNAs (miRs) are short, highly conserved small noncoding RNA molecules with fundamental roles in regulating gene expression. To identify miR biomarkers associated with idiopathic pulmonary fibrosis (IPF), the expression pattern of miRs in exosomes from bronchoalveolar lavage fluid (BALF) of elderly patients with IPF were evaluated. High‑throughput quantitative detection of miR expression using a microarray indicated that miR‑125b, miR‑128, miR‑21, miR‑100, miR‑140‑3p and miR‑374b were upregulated in patients with IPF, while let‑7d, miR‑103, miR‑26 and miR‑30a‑5p were downregulated. The expression level of miR‑30a‑5p was further examined, and its potential target genes were predicted using target gene prediction analysis software. A direct regulatory association was confirmed between miR‑30a‑5p and TGF‑β activated kinase 1/MAP3K7 binding protein 3 (TAB3) via a dual‑luciferase reporter assay. Overexpression of miR‑30a‑5p decreased TAB3, α‑smooth muscle actin and fibronectin expression in A549 cells with or without transforming growth factor‑β1 treatment. The decreased expression of miR‑30a in the BALF of patients with IPF, along with the consequential increase in TAB3 expression, may be a crucial factor in IPF progression.

Complex genetics of pulmonary diseases: lessons from genome-wide association studies and next-generation sequencing

The advent of high-throughput technologies has provided exceptional assistance for lung scientists to discover novel genetic variants underlying the development and progression of complex lung diseases. However, the discovered variants thus far do not explain much of the estimated heritability of complex lung diseases. Here, we review the literature of successfully used genome-wide association studies (GWASs) and identified the polymorphisms that reproducibly underpin the susceptibility to various noncancerous complex lung diseases or affect therapeutic responses. We also discuss the inherent limitations of GWAS approaches and how the use of next-generation sequencing technologies has furthered our understanding about the genetic determinants of these diseases. Next, we describe the contribution of the metagenomics to understand the interactions of the airways microbiome with lung diseases. We then highlight the urgent need for new integrative genomics-phenomics methods to more effectively interrogate and understand multiple downstream "omics" (eg, chromatin modification patterns). Finally, we address the scarcity of genetic studies addressing under-represented populations such as African Americans and Hispanics.