The memory of airway epithelium damage in smokers and COPD patients.

Chronic obstructive pulmonary disease (COPD), a devastating and irreversible lung disease, causes structural and functional defects in the bronchial epithelium, the (ir)reversibility of which remains unexplored in vitro. This study aimed to investigate the persistence of COPD-related epithelial defects in long-term airway epithelial cultures derived from non-smokers, smokers, and COPD patients. Barrier function, polarity, cell commitment, epithelial-to-mesenchymal transition, and inflammation were evaluated and compared with native epithelium characteristics. The role of inflammation was explored using cytokines. We show that barrier dysfunction, compromised polarity, and lineage abnormalities observed in smokers and COPD persisted for up to 10 wk. Goblet cell hyperplasia was associated with recent cigarette smoke exposure. Conversely, increased IL-8/CXCL-8 release and abnormal epithelial-to-mesenchymal transition diminished over time. These ex vivo observations matched surgical samples' abnormalities. Cytokine treatment induced COPD-like changes in control cultures and reactivated epithelial-to-mesenchymal transition in COPD cells. In conclusion, these findings suggest that the airway epithelium of smokers and COPD patients retains a multidimensional memory of its original state and previous cigarette smoke-induced injuries, maintaining these abnormalities for extended periods.

Increased Angiotensin-Converting Enzyme 2 and Loss of Alveolar Type II Cells in COVID-19-related Acute Respiratory Distress Syndrome.

Rationale: ACE2 (angiotensin-converting enzyme 2), the entry receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is expressed in type 2 alveolar epithelial cells (AT2) that may play key roles in postinjury repair. An imbalance between ACE2 and ACE has also been hypothesized to contribute to lung injury. Objectives: To characterize the expression and distribution of ACE2 and ACE and to compare AT2 with endothelial cell expression in coronavirus disease (COVID-19)-related or -unrelated acute respiratory distress syndrome (ARDS) and controls. Methods: Lung tissue stainings (using multiplex immunofluorescence) and serum concentrations of ACEs were determined retrospectively in two different cohorts of patients. AT2 and endothelial cells were stained in lung tissue for ProSPC (pro-surfactant protein C) and CD31, respectively. Measurements and Main Results: Pulmonary ACE2 expression was increased in patients with COVID-19-related and -unrelated ARDS (0.06% of tissue area and 0.12% vs. 0.006% for control subjects; P = 0.013 and P < 0.0001, respectively). ACE2 was upregulated in endothelial cells (0.32% and 0.53% vs. 0.01%; P = 0.009 and P < 0.0001) but not in AT2 cells (0.13% and 0.08% vs. 0.03%; P = 0.94 and P = 0.44). Pulmonary expression of ACE was decreased in both COVID-19-related and -unrelated ARDS (P = 0.057 and P = 0.032). Similar increases in ACE2 and decreases in ACE were observed in sera of COVID-19 (P = 0.0054 and P < 0.0001) and non-COVID-19 ARDS (P < 0.0001 and P = 0.016). In addition, AT2 cells were decreased in patients with COVID-19-related ARDS compared with COVID-19-unrelated ARDS (1.395% vs. 2.94%, P = 0.0033). Conclusions: ACE2 is upregulated in lung tissue and serum of both COVID-19-related and -unrelated ARDS, whereas a loss of AT2 cells is selectively observed in COVID-19-related ARDS.

The Epithelial-Immune Crosstalk in Pulmonary Fibrosis.

Interactions between the lung epithelium and the immune system involve a tight regulation to prevent inappropriate reactions and have been connected to several pulmonary diseases. Although the distal lung epithelium and local immunity have been implicated in the pathogenesis and disease course of idiopathic pulmonary fibrosis (IPF), consequences of their abnormal interplay remain less well known. Recent data suggests a two-way process, as illustrated by the influence of epithelial-derived periplakin on the immune landscape or the effect of macrophage-derived IL-17B on epithelial cells. Additionally, damage associated molecular patterns (DAMPs), released by damaged or dying (epithelial) cells, are augmented in IPF. Next to "sterile inflammation", pathogen-associated molecular patterns (PAMPs) are increased in IPF and have been linked with lung fibrosis, while outer membrane vesicles from bacteria are able to influence epithelial-macrophage crosstalk. Finally, the advent of high-throughput technologies such as microbiome-sequencing has allowed for the identification of a disease-specific microbial environment. In this review, we propose to discuss how the interplays between the altered distal airway and alveolar epithelium, the lung microbiome and immune cells may shape a pro-fibrotic environment. More specifically, it will highlight DAMPs-PAMPs pathways and the specificities of the IPF lung microbiome while discussing recent elements suggesting abnormal mucosal immunity in pulmonary fibrosis.

Vitamin D intoxication in patients with cystic fibrosis: report of a single-center cohort.

Vitamin D toxicity is associated with accidental overdoses due to manufacturing or intake errors and its secondary hypercalcemia can result in severe morbidity. Although patients with cystic fibrosis are potentially at increased risk for this intoxication as prescription of vitamin D preparations is a common practice in this population, the frequency of such events is currently unknown. We performed a retrospective analysis of all the files of cystic fibrosis patients followed at the Cliniques universitaires Saint-Luc over a 10-year period, recording 25(OH)- and 1,25(OH)2vitamin D levels as well as demographic data, lung function tests, Pseudomonas aeruginosa infection and results from pharmacological analysis of magistral liposoluble vitamins preparations. A total of 244 patients were included in the study. 13 patients (5%) had serum vitamin D levels corresponding to vitamin D overdose. Patients who had experienced an overdose were more likely to be F508del homozygous or suffer from exocrine pancreatic insufficiency. 2 patients developed significant hypercalcemia necessitating monitoring and hospitalization. Errors in the preparation of magistral liposoluble vitamin pills were identified in several intoxicated patients. Retrospective assessment of the dosing errors with the local pharmacists showed that trituration and dosing errors were their most frequent causes.

Familial hypersensitivity pneumonitis triggered by Cladosporium herbarum exposure during carpooling.

This series reports cases of Cladosporium herbarum-related HP due to an uncommon exposure source, illustrating the genetic background underlying HP, and highlighting the role of environmental home inquiry and serum precipitins in diagnosis and follow-up https://bit.ly/3hzvE4w.

Telomerase-related monogenic lung fibrosis presenting with subacute onset: a case report and review of literature.

Objectives: Monogenic pulmonary fibrosis related to telomerase mutations is characterized by a large spectrum of clinical presentations. The disease may affect several organs including bone marrow, liver and skin. This case illustrates some of the most salient features of telomere-related Interstitial Lung Disease(ILD). Methods: Single case study and review of the litterature. Results: We report the case of a 44-year-old man admitted to our unit for subacute pulmonary fibrosis. No underlying cause could be identified. Personal and familial history was highly suggestive of monogenic telomere related lung fibrosis. Genetic investigation confirmed a mutation in  the TERT gene, coding for one of the components of telomerase. Given the severe hypoxemia unresponsive to supportive treatment, he was referred for urgent lung transplantation, with a favourable outcome. Genetic counselling was proposed to his family. Conclusions: Telomerase-related monogenic lung fibrosis may present with a subacute onset, requiring urgent lung transplantation. Extra-thoracic clinical manifestations and familial history are key elements pointing towards the diagnosis.