Interstitial lung abnormalities (ILAs) are incidental, non-dependent parenchymal abnormalities detected on chest computed tomography (CT) in individuals without a diagnosis of interstitial lung disease (ILD). Once regarded as non-specific or age-related findings, ILAs are increasingly recognized as clinically relevant entities associated with progression to fibrotic ILD and increased mortality. Emerging molecular and epidemiological evidence indicates that ILAs share key pathogenic pathways with idiopathic pulmonary fibrosis (IPF), the archetypal progressive fibrotic ILD, including alveolar epithelial cell (AEC) stress and injury, innate immune activation, dysregulated repair, fibroblast activation, extracellular matrix (ECM) remodeling, and aging-associated cellular dysfunction. These observations suggest that ILAs may represent the early stage in the continuum of fibrotic lung disease. As such, ILAs provide a valuable opportunity to uncover early disease mechanisms and novel therapeutic targets and enable identification of individuals at increased risk of progression before clinically overt ILD develops. This mini review summarizes emerging mechanistic insights into ILAs and discusses how understanding early disease biology may inform risk stratification and preventative therapeutic strategies.

RATIONALE:Lung cancer screening regularly identifies participants with interstitial lung abnormalities (ILA). Existing classification methods may underestimate the prevalence of clinically relevant ILA phenotypes. OBJECTIVES:Can a classification system for ILAs developed in a lung cancer screening setting identify clinically relevant phenotypes? METHODS:Classification criteria based on the presence and lobar extent of traction bronchiolectasis (TBe) were developed internally by expert consensus. Categories included: no ILA, non-fibrotic ILA (NF-ILA), fibrotic ILA (F-ILA), and undiagnosed fibrotic ILD (U-ILD). Interobserver agreement was calculated between two readers. Clinical characteristics, respiratory hospitalizations, and survival were compared between participants of different ILA grades. MEASUREMENTS AND MAIN RESULTS:Eight thousand, one hundred sixty-nine participants were included in the final analysis. TBe showed improved interobserver agreement compared to the American Thoracic Society (ATS) classification, identifying 344 participants (4%) with U-ILD, 86% more than the ATS classification. An additional 405 had F-ILA (5%) and 667 had NF-ILA (8%). Compared to participants without ILA, participants with U-ILD had a higher rate of respiratory hospitalization (IRR = 4.4, 95% CI 2.7-7.5, P < .001) and increased risk of death (aHR = 2.4, 95% CI 1.9-3.0, P < .001). Increasing ILA grade was associated with higher modified Medical Research Council dyspnea scores (OR = 1.1, 95% CI 1.0-1.1, P = .02). CONCLUSIONS:In a lung cancer screening setting, an ILA scoring system focused on lobar TBe identifies more high-risk participants and demonstrates improved interobserver concordance than the ATS classification. TBe identifies participants with a respiratory phenotype who may warrant further investigation and follow-up.

BACKGROUND:Interstitial lung abnormalities (ILAs) are common incidental findings in lung cancer screening (LCS). However, challenges remain in identifying clinically relevant ILAs as highlighted in a joint statement by a European multidisciplinary task force led by the European Respiratory Society (ERS). To address these challenges, we analysed ILAs identified in one of Europe's largest LCS studies. METHODS:Of 11 635 LCS individuals, 417 screen-detected ILAs were evaluated using a new visual classification system focused on traction bronchiolectasis: non-fibrotic ILA (no traction bronchiolectasis), fibrotic ILA (traction bronchiolectasis in ≤2 lobes); undiagnosed interstitial lung disease (traction bronchiolectasis in >2 lobes). Observer agreement was compared with Fleischner Society ILA classification using Cohen's Kappa. An age, sex and smoking history-matched control group allowed the examination of associations between baseline ILA/UILD and comorbidities, forced vital capacity (FVC), hospitalisations (Student's t-tests) and mortality (univariable and multivariable Cox proportional hazards models). FINDINGS:Our visual ILA classification showed superior interobserver agreement (K=0.76) versus the Fleischner ILA classification (K=0.64). ILA/UILD subjects had more prevalent comorbidities, increasing (vs controls) approximately 10 years prior to ILA/UILD diagnosis. Compared with controls, mortality rates were 6-fold higher for UILD participants and 3-fold higher for fibrotic and non-fibrotic ILA subtypes. On multivariable Cox regression analysis, ILA/UILD presence (HR=4.90, 95% CI =2.36 to 10.10, p<0.001) showed stronger independent associations with mortality than baseline FVC (HR=0.98, 95% CI =0.96 to 1.00, p=0.04). CONCLUSION:We demonstrate a new reproducible classification of clinically important ILA/UILDs in LCS populations. We highlight that FVC shows limited associations with mortality in ILA/UILD subjects. Increased multiorgan comorbidity in ILA/UILD subjects highlights a need for comprehensive early multisystem evaluation.

RATIONALE Interstitial lung abnormalities (ILAs) are changes identified incidentally on thoracic CT without clinician suspicion of underlying interstitial lung disease (ILD) and are a common radiological finding. In the context of increased detection, there is an urgent need to develop robust and efficient management strategies for ILAs. We have developed a standardised follow-up pathway as part of the Interstitial Lung Abnormality Research Consortium UK (ILARC-UK). This is being piloted in Manchester (UK) as a virtual pathway following assessment in a dedicated ILA clinic. We present the first 12 months experience of this pathway.METHODS Referrals to the tertiary ILD service were offered assessment in the ILA clinic if they were deemed to be an incidental finding. Following assessment, virtual follow up was offered to individuals with an ILA or incidental interstitial changes identified in the context of rheumatoid arthritis (termed RA-ILA). Individuals were excluded from then ILA pathway, and offered traditional follow-up, if they had suspected sarcoidosis, post-Covid interstitial change, or a clinical suspicion of underlying ILD following assessment. The virtual follow-up pathway comprises periodic lung function testing, high resolution CT imaging and symptom questionnaire collection over a 5-year period from initial assessment.RESULTS Between March 2023 to March 2024, 868 referrals were received of which 79 patients were considered suitable for assessment in the ILA clinic. Figure 1 demonstrates the outcome of initial clinical assessment. Amongst 56 individuals with ILA and RA-ILA, 31 (55.4%) were male and mean age was 70.1 (±8.4). 35 (62,5%) were ever smokers. Mean baseline FVC % predicted was 102.3 (SD±17.4) and TLCO % predicted 71.7 (±17.2). Radiological subtypes of ILA were 25 (44.6%) subpleural fibrotic, 28 (50%) subpleural non-fibrotic and 3 (5.4%) non-subpleural non-fibrotic. 33 patients had reached the 6-month follow-up point from initial clinical review. Of those, 27 attend 6-month lung function, 1 patient died during follow-up and 5 did not attend. Mean absolute change in FVC % predicted and TLCO % predicted were -0.6% (±11.9) and -1.0% (±10.5) respectively.CONCLUSIONS We demonstrate the potential utility of a standardised ILA clinical pathway. The service has shown positive patient engagement and good compliance with virtual follow-up within the first twelve months of this new service.

Fibrosis is a chronic disease characterized by excessive extracellular matrix production, which leads to disruption of organ function. Fibroblasts are key effector cells of this process, responding chiefly to the pleiotropic cytokine transforming growth factor-β1 (TGF-β1), which promotes fibroblast to myofibroblast differentiation. We found that extracellular nutrient availability profoundly influenced the TGF-β1 transcriptome of primary human lung fibroblasts and that biosynthesis of amino acids emerged as a top enriched TGF-β1 transcriptional module. We subsequently uncovered a key role for pyruvate in influencing glutaminase (GLS1) inhibition during TGF-β1-induced fibrogenesis. In pyruvate-replete conditions, GLS1 inhibition was ineffective in blocking TGF-β1-induced fibrogenesis, as pyruvate can be used as the substrate for glutamate and alanine production via glutamate dehydrogenase (GDH) and glutamic-pyruvic transaminase 2 (GPT2), respectively. We further show that dual targeting of either GPT2 or GDH in combination with GLS1 inhibition was required to fully block TGF-β1-induced collagen synthesis. These findings embolden a therapeutic strategy aimed at additional targeting of mitochondrial pyruvate metabolism in the presence of a glutaminolysis inhibitor to interfere with the pathological deposition of collagen in the setting of pulmonary fibrosis and potentially other fibrotic conditions.

There remains a significant burden of long-term illness from COVID-19, but the possible causes are poorly understood, which limits mechanistic understanding and therapeutic intervention. Analysing the plasma proteome in acute COVID-19 has been able to identify distinct signatures and potential therapeutic targets. Utilising this method in long COVID could provide insights and identify individuals who are more likely to suffer from persistent symptoms. We used mass spectrometry (MS)-based proteomics to analyse 220 individual plasma samples. 5ul of plasma per sample was processed and analysed with the use of standard flow LC-MS in a data independent acquisition (DIA) mode. Raw data were processed by the DIANN software and the statistical analysis was performed in R (Messner, C.B. et al. Cell Systems 2020; 11(1):11-24). Of 220 plasma samples, 138 (63%) were from patients with confirmed SARS-CoV-2 infection. Median time from symptom onset to sampling date for all patients was 16 weeks (IQR 12-19). Median age was 48 years (IQR 39-61) and 55% were female. In those with confirmed infection, 80 (58%) were hospitalised and in the unconfirmed group 83 (99%) were community managed. We identified 190 unique proteins and in the hospitalised group, these cluster according to severity of illness with either increasing or decreasing levels; P<0.05. Unbiased hierarchical clustering was able to identify subsets of patients stratified according to severity of acute illness. Further analysis will explore defined clinical phenotypes correlating symptoms, physiology and imaging with protein abundance.

Fibrosis is the concluding pathological outcome and major cause of morbidity and mortality in a number of common chronic inflammatory, immune-mediated and metabolic diseases. The progressive deposition of a collagen-rich extracellular matrix (ECM) represents the cornerstone of the fibrotic response and culminates in organ failure and premature death. Idiopathic pulmonary fibrosis (IPF) represents the most rapidly progressive and lethal of all fibrotic diseases with a dismal median survival of 3.5 years from diagnosis. Although the approval of the antifibrotic agents, pirfenidone and nintedanib, for the treatment of IPF signalled a watershed moment for the development of anti-fibrotic therapeutics, these agents slow but do not halt disease progression or improve quality of life. There therefore remains a pressing need for the development of effective therapeutic strategies. In this article, we review emerging therapeutic strategies for IPF as well as the pre-clinical and translational approaches that will underpin a greater understanding of the key pathomechanisms involved in order to transform the way we diagnose and treat pulmonary fibrosis.

Fibrosis is the final pathological outcome and major cause of morbidity and mortality in many common and chronic inflammatory, immune-mediated, and metabolic diseases. Despite the growing incidence of fibrotic diseases and extensive research efforts, there remains a lack of effective therapies that improve survival. The application of omics technologies has revolutionized our approach to identifying previously unknown therapeutic targets and potential disease biomarkers. The application of metabolomics, in particular, has improved our understanding of disease pathomechanisms and garnered a wave of scientific interest in the role of metabolism in the biology of myofibroblasts, the key effector cells of the fibrogenic response. Emerging evidence suggests that alterations in metabolism not only are a feature of but also may play an influential role in the pathogenesis of fibrosis, most notably in idiopathic pulmonary fibrosis (IPF), the most rapidly progressive and fatal of all fibrotic conditions. This review will detail the role of key metabolic pathways, their alterations in myofibroblasts, and the potential this new knowledge offers for the development of antifibrotic therapeutic strategies.

The differentiation of fibroblasts into a transient population of highly activated, extracellular matrix (ECM)-producing myofibroblasts at sites of tissue injury is critical for normal tissue repair. Excessive myofibroblast accumulation and persistence, often as a result of a failure to undergo apoptosis when tissue repair is complete, lead to pathological fibrosis and are also features of the stromal response in cancer. Myofibroblast differentiation is accompanied by changes in cellular metabolism, including increased glycolysis, to meet the biosynthetic demands of enhanced ECM production. Here, we showed that transforming growth factor-beta(1) (TGF-beta(1)), the key pro-fibrotic cytokine implicated in multiple fibrotic conditions, increased the production of activating transcription factor 4 (ATF4), the transcriptional master regulator of amino acid metabolism, to supply glucose-derived glycine to meet the amino acid requirements associated with enhanced collagen production in response to myofibroblast differentiation. We further delineated the signaling pathways involved and showed that TGF-beta(1)-induced ATF4 production depended on cooperation between canonical TGF-beta(1) signaling through Smad3 and activation of mechanistic target of rapamycin complex 1 (mTORC1) and its downstream target eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1). ATF4, in turn, promoted the transcription of genes encoding enzymes of the de novo serine-glycine biosynthetic pathway and glucose transporter 1 (GLUT1). Our findings suggest that targeting the TGF-beta(1)-mTORC1-ATF4 axis may represent a novel therapeutic strategy for interfering with myofibroblast function in fibrosis and potentially in other conditions, including cancer.

Rapid diagnosis of the gene mutation associated with rifampicin resistance using GeneXpert MTB/RIF has improved the speed of diagnosis of multidrug-resistant TB; however, there are no established rapid techniques to assess for resistance to fluoroquinolones and injectable drugs. Xie et al ( N Engl J Med 2017;377:1043–54)have conducted a multicentre, prospective, blinded study in Korea and China to determine the sensitivity and specificity of a GeneXpert compatible assay which detects genes associated with resistance to isoniazid, moxifloxacin, ofloxacin, amikacin and kanamycin. A total of 405 patients were enrolled from June 2014 to June 2015 with 304 suitable samples included in the final analysis. The sensitivity of the assay for detection of Mycobacterium tuberculosis was 98%, which equalled GeneXpert MTB/RIF. The WHO recommended performance for molecular tests of drug resistance is a sensitivity of 95% and specificity of 98%. Sensitivity for resistance gene detection compared with DNA sequencing ranged from 92.7% for kanamycin to 98.1% for isoniazid; specificity was 99.6% for kanamycin and 100% for the other antibiotics. However, assay performance against phenotypic resistance characterisation was less accurate …

Introduction:There is considerable overlap in the pathomechanisms underlying idiopathic pulmonary fibrosis (IPF) and cancer. Metabolic reprogramming is a hallmark of cancer and arises to meet the biosynthetic needs of proliferating cancer cells. We hypothesise that in IPF, enhanced metabolic demand may represent a critical driver of aberrant fibroproliferative responses. Targeting metabolism may therefore represent a novel opportunity for therapeutic intervention in IPF. In this study we explored the role of glucose and glutamine metabolism during TGF-ß induced fibroblast collagen synthesis, a critical pathogenic event in IPF. Methods:Primary human lung fibroblasts were stimulated with TGF-ß (1ng/mL) for 48 hours in the presence of inhibitors of glutaminolysis, glycolysis and mTOR. Metabolic profiling was performed using 1H-NMR, [3H]-2-DG uptake, SeaHorse XF96e and colorimetric assays. Collagen I deposition was examined under macromolecular crowding conditions. Results:We show that TGF-ß leads to profound changes in fibroblast metabolism as evidenced by increased glucose and glutamine uptake, lactate production and mitochondrial respiration. Importantly, inhibition of glutamine and glucose metabolism resulted in complete inhibition of TGF-ß-induced increases in fibroblast collagen mRNA levels and protein production. We further show these metabolic changes are controlled by the metabolic regulator, mTOR, which has been widely implicated in cancer pathogenesis. Conclusion:These data support the rationale for targeting metabolic reprogramming as a novel therapeutic strategy in IPF and potentially other conditions associated with excessive collagen deposition and dysregulated mTOR signalling.

Introduction:Idiopathic pulmonary fibrosis (IPF) is a life-threatening disease characterised by excessive collagen-rich matrix formation in the lung. The role of myofibroblast metabolism in driving fibroproliferative pathomechanisms is becoming increasingly recognised and the aim of this study was to examine whether myofibroblasts increase their glucose uptake and glycolytic metabolism to support collagen synthesis. Methods: Primary human fibroblasts were stimulated with TGF-β (1ng/ml) for up to 48 hours. [3H]2DG uptake was measured in control and TGF-β-stimulated fibroblasts. Levels of mRNA and protein expression for glucose transporters and key genes involved in glycolysis were also compared. Lactate levels were also measured. The effects of glucose deprivation and glycolytic inhibition (2DG) on collagen were measured under macromolecular crowding conditions. Results: Glucose uptake was significantly higher with TGF-β stimulation compared to control fibroblasts. Over the course of 48 hours, mRNA and protein levels of GLUT1 were significantly increased in TGFβ-treated cells. LDHa, PFKFB3 and HIF1α mRNA levels were also significantly higher. There was also significantly more lactate produced. Glucose starvation and inhibition of glucose metabolism significantly reduced TGF-β-stimulated collagen production. Conclusion: We have demonstrated that increased glucose uptake and glucose metabolism is a characteristic as well as a requirement for TGF-β induced collagen synthesis.

Introduction Coughs are defined by their characteristic sound and the gold standard for determining cough frequency is by ear (Smith, J. et al. Cough 2006; 2:6). Audio editing software can be used to display graphs of sound amplitude. We measured the effect of visual information on cough counting. Methods 24h recordings were made from 3 patients with cough with the PulmoTrackTM cough monitor (KarmelSonix, Haifa, Israel). A 20-minute audio sequence from each patient was played to 10 respiratory physicians on 3 occasions with intervals of >4 weeks. No visual information was displayed on the first two occasions but on the third occasion Audacity® open source audio editing software provided simultaneous visualisation of sound amplitude. Participants counted cough sounds and cough epochs (clusters containing cough sounds separated by <2s). Results Intraclass correlation coefficients for agreement between individuals on the first, second and third counts of coughs sounds were 0.90 (95% confidence interval 0.67-1.00), 0.86 (CI 0.53-1.00) and 0.92 (CI 0.71-1.00) respectively. For cough epochs these values were 0.84 (0.53-1.00), 0.78 (0.36-0.99) and 0.94 (0.78-1.00) (Figure). Mean counts of both cough sounds and epochs were lower when using the software display. Conclusion Visual representations of audio sequences increase the consistency of cough counting. There is a tendency to discount potential coughs when using visual information. ![Figure][1] [1]: pending:yes