Structural changes in lung morphology detected by MRI after modulating therapy with elexacaftor/tezacaftor/ivacaftor in adolescent and adult patients with cystic fibrosis

INTRODUCTION

Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) improves CFTR function in cystic fibrosis (CF) patients homozygous or heterozygous for F508del mutation. The aim of the study was to evaluate the response to ELX/TEZ/IVA treatment both clinically and morphologically in terms of bronchiectasis, bronchial wall thickening, mucus plugging, abscess and consolidations.

METHODS

We retrospectively collected data from CF patients followed at Parma CF Centre (Italy) treated by ELX/TEZ/IVA between March and November 2021. Post-treatment changes in respiratory function, quality of life, sweat chloride concentration, body mass index, pulmonary exacerbations and lung structure by chest magnetic resonance imaging (MRI) were assessed. T2-and T1-weighted sequences were acquired with a 20 min-long scanning protocol on a 1.5T MRI scanner (Philips Ingenia) without administration of intravenous contrast media.

RESULTS

19 patients (32.5 ± 10.2 years) were included in the study. After 6 months of treatment with ELX/TEZ/IVA, MRI showed significant improvements in the morphological score (p < 0.001), with a reduction in bronchial wall thickening (p < 0.001) and mucus plugging (p 0.01). Respiratory function showed significant improvement in predicted FEV₁% (58.5 ± 17.5 vs 71.4 ± 20.1, p < 0.001), FVC% (79.0 ± 11.1 vs 88.3 ± 14.4, p < 0.001), FEV₁/FVC (0.61 ± 0.16 vs 0.67 ± 0.15, <0.001) and LCI_2.5% (17.8 ± 4.3 vs 15.8 ± 4.1 p < 0.005). Significant improvement was found in body mass index (20.6 ± 2.7 vs 21.9 ± 2.4, p < 0.001), pulmonary exacerbations (2.3 ± 1.3 vs 1.4 ± 1.3 p 0.018) and sweat chloride concentration (96.5 ± 36.6 vs 41.1 ± 16.9, p < 0.001).

CONCLUSIONS

Our study confirms the efficacy of ELX/TEZ/IVA in CF patients not only from a clinical point of view but also in terms of morphological changes of the lungs.

Human lung cell models to study aerosol delivery - considerations for model design and development

Human lung tissue models range from simple monolayer cultures to more advanced three-dimensional co-cultures. Each model system can address the interactions of different types of aerosols and the choice of the model and the mode of aerosol exposure depends on the relevant scenario, such as adverse outcomes and endpoints of interest. This review focuses on the functional, as well as structural, aspects of lung tissue from the upper airway to the distal alveolar compartments as this information is relevant for the design of a model as well as how the aerosol properties determine the interfacial properties with the respiratory wall. The most important aspects on how to design lung models are summarized with a focus on (i) choice of appropriate scaffold, (ii) selection of cell types for healthy and diseased lung models, (iii) use of culture condition and assembly, (iv) aerosol exposure methods, and (v) endpoints and verification process. Finally, remaining challenges and future directions in this field are discussed.

Allometric relations of respiratory variables in Amniota: Effects of phylogeny, form, and function

Biological variables are frequently described by analyzing scaling relationships of the variable against body mass (M_B). Respiratory variables are no exception and allometric relations for oxygen consumption, pulmonary ventilation, tidal volume, breathing frequency, and lung volume have been described in the literature. While the allometric relations of respiratory variables given for mammals and birds are very consistent among different studies, scaling relationships for non-avian reptiles have only been scarcely described and show considerable variation between studies. Since no comprehensive study of allometric relations of respiratory variables has been carried out comparing the different groups of non-avian reptiles, we analyzed morphological and physiological variables of the respiratory system of crocodilians, chelonians, lizards, snakes, birds, and mammals, regarding the allometric relations of each variable from a phylogenetic perspective as well as related to lung morphology. Our results indicated that few respiratory variables possess significant phylogenetic signals and that tidal volume, breathing frequency (except mammals), and air convection requirement were independent of phylogeny. Contrary to the literature, lung volume of amniotes scaled isometrically to M_B, with the exception of lizards (M_B^0.78). Air convection requirement scaled isometrically in mammals and birds, but was more variable among non-avian reptiles, from a taxonomic perspective and in regard to different lung structures. In conclusion, respiratory variables among non-avian reptiles scaled more variably than previously expected, both according to phylogeny and to lung type, warranting future studies to explore structure-function relations of the reptilian respiratory system, especially regarding snakes and crocodilians, since these groups had very few data available for analysis.

The Effects of Aging on Lung Structure and Function

Growth of the segment of the population older than 65 years has led to intensified interest in understanding the biology of aging. This article is focused on age-related alterations in lung structure that produce predictable changes in physiologic function, both at rest and during exercise. Increased insight into the physiology of the healthy aging lung should ultimately lead to improved methods of lung function assessment in the elderly (defined as those older than 65 years) as well as better understanding of the manifestations and possibly even the treatment of geriatric lung disease.

Sex-specific lung functional changes in adult mice exposed only to second-hand smoke in utero

Background

An increasing number of epidemiological and experimental studies have associated exposure to second-hand smoke (SHS) during pregnancy with adverse outcomes in newborns. As we have previously shown in mice, in utero exposure to SHS at critical stages of fetal development, results in altered lung responses and increased disease susceptibility upon re-exposure to irritants (SHS or ovalbumin) in adulthood. In this study, we asked whether the in utero SHS exposure alone is sufficient to alter lung structure and function in adult mice.

Methods

Pregnant BALB/c mice were exposed from days 6 to 19 of pregnancy to 10 mg/m³ of SHS or HEPA-filtered air. Male and female offspring (n = 13–15/group) were sacrificed at 15 weeks of age. We measured lung function with non-invasive and invasive methods, performed lung morphometric analysis on trichrome-stained lung tissue samples, and assessed lung gene expression via RNA sequencing and protein assays.

Results

In utero SHS exposure significantly increased mean linear intercept and decreased the surface area per unit volume of the lungs in both males and females, indicating perturbation in alveolar developmental processes. Tidal volume, minute volume and inspiratory capacity were significantly decreased compared with the controls only in male mice exposed in utero to SHS, suggesting that males are more sensitive than females to an SHS insult during lung development. This also suggests that in our model, lung structure changes may be necessary but are not sufficient to impair lung function. SERPINA1A, the mouse ortholog of human α1-antitrypsin, deficiency of which is a known genetic risk factor for emphysema, was down-regulated at the protein level in the in utero SHS-exposed mice. Additionally, DNMT3A protein expression was dysregulated, indicating that DNA methylation occurred in the lungs.

Conclusions

Our results indicate that in utero SHS exposure alone alters both lung function and structure well into adulthood (15 weeks) in male mice. Furthermore, lung function alterations in this model are sex-specific, with males being more susceptible to in utero SHS effects. Overall, our data suggest that in utero SHS exposure alone can predispose to adult lung diseases.

Multi-modality monitoring of cystic fibrosis lung disease: the role of chest computed tomography

Cystic fibrosis [CF] lung disease is characterized by progressive bronchiectasis and small airways disease. To monitor CF lung disease traditionally spirometry has been the most important modality. In addition to spirometry chest radiography was used to monitor progression of structural lung abnormalities. However, the importance of chest radiography in disease management has been limited due to its poor sensitivity and specificity to detect disease progression. Over the last decade chest CT has become the gold standard for monitoring the severity and progression of bronchiectasis. Small airways disease can be monitored using spirometry, multiple breath washout techniques, and chest CT. In modern CF-care a multi-modality approach is needed to monitor CF lung disease and to personalize treatment for the needs of the patient. When state-of-the-art low dose bi-annual chest CT protocols are used radiation risk is considered to be low. In between chest CT imaging, physiologic measures are important to obtain for monitoring. Stratification of monitoring protocols based on the risk profile of the patient can help us in the future to better care for people with CF.