Aging Airways: between Normal and Disease. A Multidimensional Diagnostic Approach by Combining Clinical, Functional, and Imaging Data

Investigating distributions of inhaled aerosols in the lungs of post-COVID-19 clusters through a unified imaging and modeling approach

BACKGROUND

Recent studies, based on clinical data, have identified sex and age as significant factors associated with an increased risk of long COVID. These two factors align with the two post-COVID-19 clusters identified by a deep learning algorithm in computed tomography (CT) lung scans: Cluster 1 (C1), comprising predominantly females with small airway diseases, and Cluster 2 (C2), characterized by older individuals with fibrotic-like patterns. This study aims to assess the distributions of inhaled aerosols in these clusters.

METHODS

140 COVID survivors examined around 112 days post-diagnosis, along with 105 uninfected, non-smoking healthy controls, were studied. Their demographic data and CT scans at full inspiration and expiration were analyzed using a combined imaging and modeling approach. A subject-specific CT-based computational model analysis was utilized to predict airway resistance and particle deposition among C1 and C2 subjects. The cluster-specific structure and function relationships were explored.

RESULTS

In C1 subjects, distinctive features included airway narrowing, a reduced homothety ratio of daughter over parent branch diameter, and increased airway resistance. Airway resistance was concentrated in the distal region, with a higher fraction of particle deposition in the proximal airways. On the other hand, C2 subjects exhibited airway dilation, an increased homothety ratio, reduced airway resistance, and a shift of resistance concentration towards the proximal region, allowing for deeper particle penetration into the lungs.

CONCLUSIONS

This study revealed unique mechanistic phenotypes of airway resistance and particle deposition in the two post-COVID-19 clusters. The implications of these findings for inhaled drug delivery effectiveness and susceptibility to air pollutants were explored.

Computed tomography-guided interstitial implantation of I (125) radioactive seeds in the treatment of hilar airway stenosis caused by non-small cell lung cancer

BACKGROUND

Airway stenosis secondary to non-small cell lung cancer (NSCLC) is one of the severe complications that can lead to life-threatening outcomes.

OBJECTIVE

To investigate the clinical utility of computed tomography (CT)-guided interstitial implantation of radioactive I-125 seeds in the treatment of hilar airway stenosis caused by NSCLC.

METHODS

The cases of hilar airway stenosis caused by NSCLC in our hospital from 2017 to 2022 were collected and divided into observation and control groups. Both groups underwent conventional lung cancer treatment, and the observation group was treated with CT-guided interstitial implantation of radioactive I-125 seeds. The mean tumor diameter, hilar airway stenosis, and obstructive pneumonia scores at 3 months after treatment were compared between the two groups.

RESULTS

After 3 months of treatment, the mean tumor diameter (28.8 ± 9.3 mm vs 49.33 ± 16.75 mm, P < 0.001), hilar airway stenosis (20.55 ± 30.36% vs 84.85 ± 26.19%, P < 0.001), and obstructive pneumonia score (2.19 ± 1.41 vs 3.48 ± 1.12, P < 0.001) of the observation group were significantly lower than those of the control group.

CONCLUSION

CT-guided interstitial implantation of I (125) radioactive seeds in the treatment of hilar airway stenosis caused by NSCLC can effectively reduce the tumor volume, relieve airway stenosis, and alleviate the associated obstructive pneumonia and has a certain value of application in the clinic.

Transcriptomic profiles of age-related genes in female trachea and bronchus

Background: Studies demonstrated that age-related cellular and functional changes of airway significantly contribute to the pathogenesis of many airway diseases. However, our understanding on the age-related molecular alterations of human airway remains inadequate.

Methods: Airway (trachea and bronchus) brushing specimens were collected from 14 healthy, female non-smokers with ages ranging from 20 to 60 years. Bulk RNA sequencing was performed on all the specimens (n = 28). Airway cell types and their relative proportions were estimated using CIBERSORTx. The cell type proportions were compared between the younger (age 20–40) and elder group (age 40–60) in the trachea and bronchus respectively. The linear association between cell type proportion and age was assessed using the Pearson correlation coefficient. Differentially expressed genes (DEGs) between the two age groups were identified using DESeq2. Three kinds of enrichment analysis of the age-related DEGs were performed, including Gene ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and disease enrichment analysis.

Results: Sixteen and thirteen cell types were separately identified in tracheal and bronchial brushings, with the airway epithelial cells (including suprabasal, submucosal gland (SMG) goblet, serous, secretory, multiciliated, cycling.basal, basal cells) accounting for 85.1% in the trachea and 92.5% in the bronchus. The lymphatic cell and NK cells had a higher abundance ratio in the trachea, compared with the bronchus. The proportion of basal cells was negatively related to age both in the trachea and bronchus. Thirty-one and fifty-two age-related DEGs (p &lt; 0.1) were identified in the trachea and bronchus, respectively. Among them, five common DEGs (CXCL2, CXCL8, TCIM, P4HA3, AQP10) were identified. Pathway enrichment analysis showed both tracheal and bronchial age-related DEGs were primarily involved in immune regulatory signaling pathways (TNF, NF-kappa B, IL-17 et al.). Disease enrichment analysis suggested that tracheal age-related DEGs significantly related to asthmatic pulmonary eosinophilia, and chronic airflow obstruction et al., and that bronchial age-related DEGs were enriched in airflow obstruction, bronchiectasis, pulmonary emphysema, and low respiratory tract infection et al.

Conclusion: We found the proportion of basal cells decreased with age in both the trachea and bronchus, suggesting a weakening of their self-renew ability with age. We identified transcriptomic signature genes associated with the early aging process of the human trachea and bronchus, and provided evidence to support that changes in their immune regulatory function may play critical roles in age-related airway diseases.

Aging-Related Findings of the Respiratory System in Chest Imaging: Pearls and Pitfalls

Purpose of Review

The purpose of this review is to describe the main features of the aging chest, studied through different imaging modalities.

Recent Findings

Aging-related changes of the respiratory system are inevitable. Therefore, it is mandatory to be familiar with the para-physiological changes that occurs, in order to avoid inappropriate interpretation of radiological findings that put patients at risk of over or undertreatment.

Summary

The role of the radiologist is fundamental in evaluating aging-related processes affecting the respiratory system and in distinguishing them from frank diseases.

Risk factors of complications during noninvasive mechanical ventilation -assisted flexible bronchoscopy

PURPOSE

Flexible bronchoscopy (FB) causes airway narrowing and may cause respiratory failure (RF). Noninvasive mechanical ventilation (NIV) is used to treat RF. Until recently, little was known about noninvasive mechanical ventilation assisted flexible bronchoscopy (NIV-FB) risk and complications.

MATERIALS AND METHODS

A retrospective analysis of NIV-FB performed in 20 consecutive months (July 1, 2018-February 29, 2020) was performed. Indications for: FB and NIV, as well as impact of comorbidities, blood gas results, pulmonary function test results and sedation depth, were analyzed to reveal NIV-FB risk. Out of a total of 713 FBs, NIV-FB was performed in 50 patients with multiple comorbidities, acute or chronic RF, substantial tracheal narrowing, or after previously unsuccessful FB attempt.

RESULTS

In three cases, reversible complications were observed. Additionally, due to the severity of underlining disease, two patients were transferred to the ICU where they passed away after >48h. In a single variable analysis, PaO₂ 69 ​± ​18.5 and 49 ​± ​9.0 [mmHg] (p ​< ​0.05) and white blood count (WBC) 10.0 ​± ​4.81 and 14.4 ​± ​3.10 (p ​< ​0.05) were found predictive for complications. Left heart disease indicated unfavorable NIV-FB outcome (p ​= ​0.046).

CONCLUSIONS

NIV-FB is safe in severely ill patients, however procedure-related risk should be further defined and verified in prospective studies.

Why We Should Target Small Airways Disease in Our Management of Chronic Obstructive Pulmonary Disease

For more than 50 years, small airways disease has been considered a key feature of chronic obstructive pulmonary disease (COPD) and a major cause of airway obstruction. Both preventable and treatable, small airways disease has important clinical consequences if left unchecked. Small airways disease is associated with poor spirometry results, increased lung hyperinflation, and poor health status, making the small airways an important treatment target in COPD. The early detection of small airways disease remains the key barrier; if detected early, treatments designed to target small airways may help reduce symptoms and allow patients to maintain their activities. Studies are needed to evaluate the possible role of new drugs and novel drug formulations, inhalers, and inhalation devices for treating small airways disease. These developments will help to improve our management of small airways disease in patients with COPD.

Fully integrating pathophysiological insights in COPD: an updated working disease model to broaden therapeutic vision

Our starting point is that relatively new findings into the pathogenesis and pathophysiology of airway disease in smokers that lead to chronic obstructive pulmonary disease (COPD) need to be reassessed as a whole and integrated into "mainstream" thinking along with traditional concepts which have stood the test of time. Such a refining of the accepted disease paradigm is urgently needed as thinking on therapeutic targets is currently under active reconsideration. We feel that generalised airway wall "inflammation" is unduly over-emphasised, and highlight the patchy and variable nature of the pathology (with the core being airway remodelling). In addition, we present evidence for airway wall disease in smokers/COPD as including a hypocellular, hypovascular, destructive, fibrotic pathology, with a likely spectrum of epithelial-mesenchymal transition states as significant drivers of this remodelling. Furthermore, we present data from a number of research modalities and integrate this with the aetiology of lung cancer, the role of chronic airway luminal colonisation/infection by a specific group of "respiratory" bacteria in smokers (which results in luminal inflammation) and the central role for oxidative stress on the epithelium. We suggest translation of these insights into more focus on asymptomatic smokers and early COPD, with the potential for fresh preventive and therapeutic approaches.

Increased myofibroblasts in the small airways, and relationship to remodelling and functional changes in smokers and COPD patients: potential role of epithelial-mesenchymal transition

Introduction

Previous reports have shown epithelial-mesenchymal transition (EMT) as an active process that contributes to small airway fibrotic pathology. Myofibroblasts are highly active pro-fibrotic cells that secrete excessive and altered extracellular matrix (ECM). Here we relate small airway myofibroblast presence with airway remodelling, physiology and EMT activity in smokers and COPD patients.

Methods

Lung resections from nonsmoker controls, normal lung function smokers and COPD current and ex-smokers were stained with anti-human α-smooth muscle actin (SMA), collagen 1 and fibronectin. αSMA⁺ cells were computed in reticular basement membrane (Rbm), lamina propria and adventitia and presented per mm of Rbm and mm² of lamina propria. Collagen-1 and fibronectin are presented as a percentage change from normal. All analyses including airway thickness were measured using Image-pro-plus 7.0.

Results

We found an increase in subepithelial lamina propria (especially) and adventitia thickness in all pathological groups compared to nonsmoker controls. Increases in αSMA⁺ myofibroblasts were observed in subepithelial Rbm, lamina propria and adventitia in both the smoker and COPD groups compared to nonsmoker controls. Furthermore, the increase in the myofibroblast population in the lamina propria was strongly associated with decrease in lung function, lamina propria thickening, increase in ECM protein deposition, and finally EMT activity in epithelial cells.

Conclusions

This is the first systematic characterisation of small airway myofibroblasts in COPD based on their localisation, with statistically significant correlations between them and other pan-airway structural, lung function and ECM protein changes. Finally, we suggest that EMT may be involved in such changes.

The Geriatric Patient: The Ideal One for Chest Ultrasonography? A Review From the Chest Ultrasound in the Elderly Study Group (GRETA) of the Italian Society of Gerontology and Geriatrics (SIGG)

OBJECTIVES

To investigate the current evidence on the use of point-of-care chest ultrasonography in older patients and geriatric settings and present the current state of the art of chest ultrasound applications.

DESIGN

Special article based on a literature review with narrative analyses and expert clinical knowledge.

SETTING AND PARTICIPANTS

All studies performed in a geriatric setting were included. Observational and intervention studies and meta-analyses including participants aged ≥70 years were also considered, even if not specifically focused on a geriatric setting.

MEASURES

Data on participant characteristics, diagnostic accuracy of chest ultrasonography, and outcomes were collected for each considered study. Data were analyzed and discussed with a particular focus on the possible applications and advantages of chest ultrasonography in geriatric medicine, underlining the possible areas of future research.

RESULTS

We found only 5 studies on the diagnostic accuracy and prognostic relevance of chest ultrasonography in geriatrics. However, several studies performed in emergency departments, intensive care units, and internal medicine wards included a large number of participants ≥70 years old; they suggest that chest ultrasonography may represent a valid aid to the diagnostics of acute dyspnea, pneumonia, acute heart failure, pneumothorax, and pleural diseases, with an accuracy in some cases superior to standard x-rays, especially when mobility limitation is present. Diaphragm ultrasonography may also represent a valid tool to guide mechanical ventilation weaning in older patients with acute respiratory failure.

CONCLUSIONS AND IMPLICATIONS

Chest ultrasonography may represent a valid bedside diagnostic aid to the management of acute respiratory diseases in older patients. However, specific evidence is lacking for geriatric patients. Future research will need to focus on defining the reference standards and the diagnostic accuracy for older patients with frailty and multimorbidity, cost-efficacy and cost-effectiveness of the technique, its impact for clinical outcomes, and role for follow-up in the post-acute care.

Dietary nutrients associated with preservation of lung function in Hispanic and non-Hispanic white smokers from New Mexico

Background

COPD is the third leading cause of death in the United States. Cigarette smoking accelerates the age-related forced expiratory volume in 1 s (FEV₁) decline, an important determinant for the genesis of COPD. Hispanic smokers have lower COPD prevalence and FEV₁ decline than non-Hispanic whites (NHWs).

Patients and methods

A nutritional epidemiological study was conducted in the Lovelace Smokers cohort (LSC; n=1,829) and the Veterans Smokers cohort (n=508) to identify dietary nutrients (n=139) associated with average FEV₁ and its decline and to assess whether nutrient intakes could explain ethnic disparity in FEV₁ decline between Hispanics and NHW smokers.

Results

Nutrients discovered and replicated to be significantly associated with better average FEV₁ included magnesium, folate, niacin, vitamins A and D, eicosenoic fatty acid (20:1n9), eicosapentaenoic acid (20:5n3), docosapentaenoic acid (DPA; 22:5n3), docosahexaenoic acid (22:6n3), and fiber. In addition, greater intakes of eicosenoic fatty acid and DPA were associated with slower FEV₁ decline in the LSC. Among omega 3 polyunsaturated fatty acids, DPA is the most potent nutrient associated with better average FEV₁ and slower FEV₁ decline. Adverse effect of continuous current smoking on FEV₁ decline was completely negated in LSC members with high DPA intake (>20 mg/day). Slower FEV₁ decline in Hispanics compared to NHWs may be due to the greater protection of eicosenoic fatty acid and DPA for FEV₁ decline rather than greater intake of protective nutrients in this ethnic group.

Conclusion

The protective nutrients for the preservation of FEV₁ in ever smokers could lay foundation for designing individualized nutritional intervention targeting “optimal physiological levels” in human to improve lung function in ever smokers. Ethnic disparity in FEV₁ decline may be explained by difference in magnitude of protection of dietary intakes of eicosenoic fatty acid and DPA between Hispanics and NHWs.