Daily Respiratory Research Analysis
Analyzed 195 papers and selected 3 impactful papers.
Summary
Three papers stood out today: a large, phenotyped ARDS cohort linked lung- and chest-wall mechanics to mortality differently across inflammatory subtypes; a multi‑registry analysis showed diabetes markedly worsens bronchiectasis outcomes with distinct microbial and inflammatory signatures; and a mechanistic study in silicosis uncovered a SIRT6–ATF3–importin α pathway driving macrophage senescence and fibrosis, nominating itraconazole as a potential inhibitor.
Research Themes
- Phenotype-informed ventilation and mechanics in ARDS
- Metabolic comorbidity (diabetes) shaping bronchiectasis outcomes and microbiome
- Macrophage senescence and nuclear transport pathways driving lung fibrosis (silicosis)
Selected Articles
1. Effects of inflammatory phenotypes in acute respiratory distress syndrome on mortality and partitioning of lung and chest wall mechanics in patients in the USA and Canada: a retrospective cohort study.
Across 890 ARDS patients phenotyped as hyper- or hypoinflammatory, 60-day mortality was 55% vs 29%. Elevated respiratory system/transpulmonary driving pressures and end-expiratory transpulmonary pressure showed stronger associations with mortality in hypoinflammatory ARDS, while hyperinflammatory deaths were more driven by extrapulmonary organ failure.
Impact: This study links ARDS inflammatory phenotypes with differential sensitivity to ventilatory mechanics, informing phenotype-enriched trials and precision monitoring of driving/transpulmonary pressures.
Clinical Implications: Maintain strict lung-protective ventilation with attention to driving and transpulmonary pressures, particularly in hypoinflammatory ARDS; consider phenotype-based enrichment for future interventional trials rather than changing ventilator targets solely by phenotype.
Key Findings
- Among 890 ARDS patients, 60-day mortality was 55% (hyperinflammatory) vs 29% (hypoinflammatory).
- High respiratory system driving pressure (≥15 cmH2O) and related mechanics had a stronger association with mortality in hypoinflammatory ARDS.
- Extrapulmonary organ failure largely accounted for excess mortality in hyperinflammatory ARDS.
Methodological Strengths
- Harmonized data from a randomized trial cohort (EPVent-2) and a large retrospective cohort with oesophageal manometry.
- Multivariable Cox modeling stratified by validated ARDS inflammatory phenotypes.
Limitations
- Retrospective design with potential residual confounding and selection bias.
- Generalizability may be limited to centers with oesophageal manometry expertise; some variables incomplete.
Future Directions: Prospective trials that enrich by inflammatory phenotype to test ventilatory or adjunctive strategies; evaluate bedside phenotype assignment and continuous transpulmonary pressure titration.
BACKGROUND: Inflammatory phenotypes of acute respiratory distress syndrome (ARDS) predict outcomes and can respond differently to treatment strategies. We aimed to establish whether these phenotypes differ in respiratory mechanics and in response to lung-protective ventilation strategies. METHODS: In this retrospective cohort study, data from two cohorts were harmonised. Patients with moderate-to-severe ARDS with oesophageal manometry data from the EPVent-2 trial (14 hospitals across the USA and Canada) and a retrospective cohort at Beth Israel Deaconess Medical Center (Boston, MA, USA) were merged and lung mechanics were compared. Patients had to be aged 18 years or older, have moderate to severe ARDS, and be monitored with oesophageal manometry. To analyse the primary outcome of 60-day mortality after ARDS onset, we used multivariable Cox models for each inflammatory phenotype to study the associations between measures of lung-protective ventilation (driving pressure, transpulmonary driving pressure, and end-expiratory transpulmonary pressure) and 60-day mortality in all patients who had complete data for all variables. FINDINGS: Between Jan 1, 2008, and Jan 31, 2024, 5778 patients were assessed for eligibility (200 in the EPVent-2 cohort and 5578 in the BIDMC cohort). Of these patients, 890 were included in this study cohort (200 from the EPVent-2 trial and 690 from the retrospective cohort), of whom 424 (48%) had the hyperinflammatory phenotype and 466 (52%) had the hypoinflammatory phenotype. 232 (55%) patients in the hyperinflammatory group and 136 (29%) patients in the hypoinflammatory group died within 60 days (p<0·0001). The effects on 60-day mortality were more pronounced among patients with the hypoinflammatory phenotype than the hyperinflammatory phenotype for high respiratory system driving pressure (≥15 cm H...
2. SIRT6-Mediated Deacetylation of ATF3 Promotes Silica-Induced Lung Fibrosis by Enhancing its Nuclear Import via Binding to Importin α.
Using human and mouse scRNA‑seq and mechanistic assays, the study shows SIRT6 deacetylates ATF3 to promote importin‑α–mediated nuclear import, mitochondrial dysfunction, and macrophage senescence, driving silica‑induced fibrosis via SPP1–CD44 signaling. Itraconazole disrupted ATF3–importin α binding, attenuating macrophage senescence and pulmonary fibrosis.
Impact: It identifies a previously unrecognized SIRT6–ATF3–importin α axis controlling macrophage senescence and fibrosis and proposes a repurposable small molecule (itraconazole) to target this pathway.
Clinical Implications: Points to SIRT6/ATF3/importin α and SPP1–CD44 as druggable targets for silicosis and possibly other fibrotic lung diseases; supports testing itraconazole or tailored inhibitors to block ATF3 nuclear import.
Key Findings
- scRNA-seq linked ATF3-driven macrophage senescence to silicosis progression in human and mouse lungs.
- SIRT6-mediated deacetylation of ATF3 enhanced importin-α–dependent nuclear import, activated MGARP, and triggered mitochondrial dysfunction and senescence.
- Senescent macrophages activated fibroblasts via SPP1–CD44 signaling; itraconazole blocked ATF3–importin α binding and reduced pulmonary fibrosis.
Methodological Strengths
- Human and murine scRNA-seq integrated with mechanistic validation across molecular, cellular, and in vivo levels.
- Target engagement shown via competitive binding and functional reversal with a small-molecule inhibitor.
Limitations
- Preclinical mechanistic study; clinical efficacy and safety of targeting this axis remain untested.
- Dosing, pharmacokinetics, and off-target effects of itraconazole for antifibrotic use require rigorous evaluation.
Future Directions: Validate the SIRT6–ATF3–importin α axis in larger human cohorts; develop selective inhibitors of ATF3 nuclear import; conduct preclinical-to-clinical translation studies in silicosis.
Silicosis is the most common occupational lung disease caused by respirable crystalline silica inhalation, with limited therapeutic options. Cellular senescence plays a critical role in the pathogenesis of lung diseases, while the role of senescent macrophages in silicosis remains unclear. Single-cell RNA sequencing (scRNA-seq) of healthy and silicosis human and mouse lung tissues revealed that activating transcription factor 3 (ATF3)-mediated macrophage senescence is closely linked to silicosis progression. Mechanistically, Sirtuin 6 (SIRT6)-mediated ATF3 deacetylation enhanced its nuclear transport and subsequently activated mitochondria-localized glutamic acid-rich protein (MGARP) transcription, thereby causing mitochondrial dysfunction and macrophage senescence. Senescent macrophages promoted fibroblast activation via the secreted phosphoprotein 1 (SPP1)-cluster of differentiation 44 (CD44) signaling pathway. Furthermore, the nuclear transport protein importin α and the molecular chaperone protein heat shock protein 70 (HSP70) competitively bound to ATF3, preventing its lysosomal degradation while promoting its nuclear import during macrophage senescence. Moreover, the small-molecule inhibitor Itraconazole, which targets the binding site of ATF3 and importin α, could reduce ATF3 nuclear entry, macrophage senescence, and pulmonary fibrosis (PF). Collectively, our study provided insights into the mechanism by which deacetylated ATF3 facilitates silicosis progression via increased nuclear transport and macrophage senescence, and indicated potential therapeutic targets for PF.
3. Comorbid diabetes disease severity and microbial changes in patients with bronchiectasis: a combined analysis of data from the EMBARC, EMBARC-India, Australian, and BE-China registries.
Across 30,263 bronchiectasis patients, diabetes (8.2%) was linked to higher exacerbation rates (IRR 1.18), hospitalizations (IRR 1.57), and 5‑year mortality (HR 1.80). Diabetic bronchiectasis showed enrichment of Enterobacteriaceae, Moraxella catarrhalis, and Haemophilus influenzae, and elevated serum Gal‑4 and GDF‑15.
Impact: Defines diabetes as a strong, multi-omic risk modifier in bronchiectasis across continents, providing actionable signals for risk stratification and integrated care.
Clinical Implications: Incorporate diabetes status into bronchiectasis risk scores and care plans; intensify infection surveillance and comorbidity management; consider microbiome-targeted strategies in diabetic bronchiectasis.
Key Findings
- Diabetes in bronchiectasis was associated with higher exacerbations (IRR 1.18), hospitalizations (IRR 1.57), and 5‑year mortality (HR 1.80) after adjustment.
- Microbiome shifts included increased Enterobacteriaceae, Moraxella catarrhalis, and Haemophilus influenzae; serum Gal‑4 and GDF‑15 were elevated.
- Diabetic bronchiectasis patients had higher comorbidity burden and disease severity scores (BSI, MRC dyspnea).
Methodological Strengths
- Very large, multinational registries with CT‑confirmed bronchiectasis and adjusted analyses.
- Integration of sputum 16S rRNA sequencing and serum proteomics in a subcohort.
Limitations
- Observational design limits causal inference; heterogeneity across registries and healthcare systems.
- Microbiome/proteomic data available only in subcohorts, potentially limiting generalizability.
Future Directions: Develop bronchiectasis risk tools incorporating diabetes and biomarkers; test targeted antimicrobial and microbiome-modulatory strategies in diabetic bronchiectasis.
BACKGROUND: Bronchiectasis and diabetes commonly coexist and are associated with immune dysfunction and increased susceptibility to infection. Although diabetes is associated with worse prognosis in cystic fibrosis-related bronchiectasis, data are scarce for its impact on non-cystic fibrosis bronchiectasis. This study aimed to characterise the impact of diabetes on clinical outcomes and microbial and inflammatory profiles in patients with bronchiectasis. METHODS: This analysis comprised data from the European Bronchiectasis Registry (EMBARC), Respiratory Research Network of India (EMBARC-India), Chinese Bronchiectasis Registry (BE-China), and Australian Bronchiectasis Registry (ABR); 30 263 patients with CT-confirmed bronchiectasis in 33 countries were included in the analysis: 16 963 from EMBARC (Jan 12, 2015, to April 12, 2022), 2361 from EMBARC-India plus additional Asian countries (June 1, 2015, to Sept 1, 2017), 10 324 from BE-China (Jan 10, 2020, to March 31, 2024), and 615 from the ABR (March 7, 2016, to Sept 11, 2018). Clinical data were compared between patients with and without diabetes. Long-term outcome data were available in EMBARC and EMBARC-India. Microbiome and inflammatory profiles were characterised in a sub-cohort of EMBARC patients by sputum 16S rRNA sequencing (n=433) and serum Olink (n=479). FINDINGS: 2487 (8·2%) of 30 263 patients with bronchiectasis had diabetes. Patients with diabetes had a higher prevalence of comorbidities than those without diabetes, including cardiovascular disorders (53·5% vs 21·8%, p<0·0001), asthma (27·5% vs 21·0%, p<0·0001), and chronic obstructive pulmonary disease (34·3% vs 19·0%, p<0·0001). Patients with diabetes had more severe disease than those without diabetes, with higher Bronchiectasis Severity Index scores (8 [IQR 5-12] vs 7 [4-10], p<0·0001) and UK Medical Research Council (MRC) dyspnoea scores (p<0·0001) and more hospital admissions in the previous year (p<0·0001). After adjustment for confounders, outcomes were significantly worse in patients with diabetes than in those without diabetes, including more frequent exacerbations (incidence rate ratio [IRR] 1·18 [95% CI 1·09-1·28], p<0·0001), hospital admissions (IRR 1·57 [1·40-1·76], p<0·0001), and higher 5-year mortality (hazard ratio 1·80 [1·53-2·12], p<0·0001). The sputum microbiome was significantly altered in patients with diabetes compared to those without diabetes, with increased isolation of Enterobacteriaceae (p<0·0001), Moraxella catarrhalis (p=0·0035), and Haemophilus influenzae (p=0·046). In serum, Gal-4 and GDF-15, established biomarkers of disease severity and cardiovascular risk in diabetes, were significantly increased in patients with diabetes (Gal-4, p<0·0001; GDF-15, p=0·0019). INTERPRETATION: Patients with diabetes and bronchiectasis are a high-risk population with more severe disease, worse outcomes, increased comorbidities, and increased risk of infections compared with patients without diabetes. These findings support inclusion of diabetes as a risk factor in individualised risk assessments for bronchiectasis.