A novel in vitro tubular model to recapitulate features of distal airways: The bronchioid.

BACKGROUND: Airflow limitation is the hallmark of obstructive pulmonary diseases, with the distal airways representing a major site of obstruction. Although numerous in vitro models of bronchi already exist, there is currently no culture system for obstructive diseases that reproduces the architecture and function of small airways. Here, we aimed to engineer a model of distal airways to overcome the limitations of current culture systems. METHODS: We developed a so-called bronchioid model by encapsulating human bronchial adult stem cells derived from clinical samples in a tubular scaffold made of alginate gel. RESULTS: This template drives the spontaneous self-organisation of epithelial cells into a tubular structure. Fine control of the level of contraction is required to establish a model of the bronchiole, which has a physiologically relevant shape and size. 3D imaging, gene expression and single-cell RNA-seq analysis of bronchioids made of bronchial epithelial cells revealed tubular organisation, epithelial junction formation and differentiation into ciliated and goblet cells. Ciliary beating is observed, at a decreased frequency in bronchioids made of cells from COPD patients. The bronchioid can be infected by rhinovirus. An air-liquid interface is introduced that modulates gene expression. CONCLUSION: Here, we provide a proof of concept of a perfusable bronchioid with proper mucociliary and contractile functions. The key advantages of our approach, such as the air‒liquid interface, lumen accessibility, recapitulation of pathological features and possible assessment of clinically relevant endpoints, will make our pulmonary organoid-like model a powerful tool for preclinical studies.

Rhinovirus infection of bronchial epithelium induces specific bronchial smooth muscle cell migration of severe asthmatic patients.

BACKGROUND: Patients with severe asthma show an increase in both exacerbation frequency and bronchial smooth muscle (BSM) mass. Rhinovirus (RV) infection of the bronchial epithelium (BE) is the main trigger of asthma exacerbations. Histological analysis of biopsies shows that a close connection between BE and hypertrophic BSM is a criterion for severity of asthma. OBJECTIVE: We hypothesized that RV infection of BE specifically increases BSM-cell migration from patients with asthma. METHODS: Serum samples, biopsies, or BSM cells were obtained from 86 patients with severe asthma and 31 subjects without asthma. BE cells from subjects without asthma were cultured in an air-liquid interface and exposed to RV-16. Migration of BSM cells was assessed in response to BE supernatant using chemotaxis assays. Chemokine concentrations were analyzed by transcriptomics and ELISAs. Immunocytochemistry, western blotting, and flow cytometry were used to quantify CXCR3 isoform distribution. CXCR3 downstream signaling pathways were assessed by calcium imaging and western blots. RESULTS: BSM cells from patients with severe asthma specifically migrated toward RV-infected BE, whereas those from subjects without asthma did not. This specific migration is driven by BE C-X-C motif chemokine ligand 10, which was increased in vitro in response to RV infection as well as in vivo in serum from exacerbating patients with severe asthma. The mechanism is related to both decreased expression and activation of the CXCR3-B-specific isoform in BSM cells from those with severe asthma. CONCLUSIONS: We have demonstrated a novel mechanism of BSM remodeling in patients with severe asthma following RV exacerbation. This study highlights the C-X-C motif chemokine ligand 10/CXCR3-A axis as a potential therapeutic target in severe asthma.

Crucial role of fatty acid oxidation in asthmatic bronchial smooth muscle remodelling.

BACKGROUND: Bronchial smooth muscle (BSM) remodelling in asthma is related to an increased mitochondrial biogenesis and enhanced BSM cell proliferation in asthma. Since mitochondria produce the highest levels of cellular energy and fatty acid ß-oxidation is the most powerful way to produce ATP, we hypothesised that, in asthmatic BSM cells, energetic metabolism is shifted towards the ß-oxidation of fatty acids. OBJECTIVES: We aimed to characterise BSM cell metabolism in asthma both in vitro and ex vivo to identify a novel target for reducing BSM cell proliferation. METHODS: 21 asthmatic and 31 non-asthmatic patients were enrolled. We used metabolomic and proteomic approaches to study BSM cells. Oxidative stress, ATP synthesis, fatty acid endocytosis, metabolite production, metabolic capabilities, mitochondrial networks, cell proliferation and apoptosis were assessed on BSM cells. Fatty acid content was assessed in vivo using matrix-assisted laser desorption/ionisation spectrometry imaging. RESULTS: Asthmatic BSM cells were characterised by an increased rate of mitochondrial respiration with a stimulated ATP production and mitochondrial ß-oxidation. Fatty acid consumption was increased in asthmatic BSM both in vitro and ex vivo. Proteome remodelling of asthmatic BSM occurred via two canonical mitochondrial pathways. The levels of carnitine palmitoyl transferase (CPT)2 and low-density lipoprotein (LDL) receptor, which internalise fatty acids through mitochondrial and cell membranes, respectively, were both increased in asthmatic BSM cells. Blocking CPT2 or LDL receptor drastically and specifically reduced asthmatic BSM cell proliferation. CONCLUSION: This study demonstrates a metabolic switch towards mitochondrial ß-oxidation in asthmatic BSM and identifies fatty acid metabolism as a new key target to reduce BSM remodelling in asthma.

Fibrocyte accumulation in the airway walls of COPD patients.

The remodelling mechanism and cellular players causing persistent airflow limitation in COPD remain largely elusive. We have recently demonstrated that circulating fibrocytes, a rare population of fibroblast-like cells produced by the bone marrow stroma, are increased in COPD patients during an exacerbation. We aimed to quantify fibrocyte density in situ in bronchial specimens from both control subjects and COPD patients, to define associations with relevant clinical, functional and computed tomography (CT) parameters, and to investigate the effect of the epithelial microenvironment on fibrocyte survival in vitro ("Fibrochir" study).A total of 17 COPD patients and 25 control subjects, all requiring thoracic surgery, were recruited. Using co-immunostaining and image analysis, we identified CD45+ FSP1+ cells as tissue fibrocytes, and quantified their density in distal and proximal bronchial specimens. Fibrocytes, cultured from the blood samples of six COPD patients, were exposed to primary bronchial epithelial cell secretions from control subjects or COPD patients.We demonstrate that fibrocytes are increased in both distal and proximal tissue specimens of COPD patients. The density of fibrocytes is negatively correlated with lung function parameters and positively correlated with bronchial wall thickness as assessed by CT scan. A high density of distal bronchial fibrocytes predicts the presence of COPD with a sensitivity of 83% and a specificity of 70%. Exposure of fibrocytes to COPD epithelial cell supernatant favours cell survival.Our results thus demonstrate an increased density of fibrocytes within the bronchi of COPD patients, which may be promoted by epithelial-derived survival-mediating factors.

Impact of donor, recipient and matching on survival after high emergency lung transplantation in France.

INTRODUCTION: Since July 2007, the French high emergency lung transplantation (HELT) allocation procedure prioritises available lung grafts to waiting patients with imminent risk of death. The relative impacts of donor, recipient and matching on the outcome following HELT remain unknown. We aimed at deciphering the relative impacts of donor, recipient and matching on the outcome following HELT in an exhaustive administrative database. METHODS: All lung transplantations performed in France were prospectively registered in an administrative database. We retrospectively reviewed the procedures performed between July 2007 and December 2015, and analysed the impact of donor, recipient and matching on overall survival after the HELT procedure by fitting marginal Cox models. RESULTS: During the study period, 2335 patients underwent lung transplantation in 11 French centres. After exclusion of patients with chronic obstructive pulmonary disease/emphysema, 1544 patients were included: 503 HELT and 1041 standard lung transplantation allocations. HELT was associated with a hazard ratio for death of 1.41 (95% CI 1.22-1.64; p<0.0001) in univariate analysis, decreasing to 1.32 (95% CI 1.10-1.60) after inclusion of recipient characteristics in a multivariate model. A donor score computed to predict long-term survival was significantly different between the HELT and standard lung transplantation groups (p=0.014). However, the addition of donor characteristics to recipient characteristics in the multivariate model did not change the hazard ratio associated with HELT. CONCLUSIONS: This exhaustive French national study suggests that HELT is associated with an adverse outcome compared with regular allocation. This adverse outcome is mainly related to the severity status of the recipients rather than donor or matching characteristics.

Bronchial Smooth Muscle Remodeling in Nonsevere Asthma.

RATIONALE: Increased bronchial smooth muscle (BSM) mass is a key feature of airway remodeling that classically distinguishes severe from nonsevere asthma. Proliferation of BSM cells involves a specific mitochondria-dependent pathway in individuals with severe asthma. However, BSM remodeling and mitochondrial biogenesis have not been examined in nonsevere asthma. OBJECTIVES: We aimed to assess whether an increase in BSM mass was also implicated in nonsevere asthma and its relationship with mitochondria and clinical outcomes. METHODS: We enrolled 34 never-smoker subjects with nonsevere asthma. In addition, we recruited 56 subjects with nonsevere asthma and 19 subjects with severe asthma as comparative groups (COBRA cohort [Cohorte Obstruction Bronchique et Asthme; Bronchial Obstruction and Asthma Cohort; sponsored by the French National Institute of Health and Medical Research, INSERM]). A phenotypic characterization was performed using questionnaires, atopy and pulmonary function testing, exhaled nitric oxide measurement, and blood collection. Bronchial biopsy specimens were processed for immunohistochemistry and electron microscopy analysis. After BSM remodeling assessment, subjects were monitored over a 12-month period. MEASUREMENTS AND MAIN RESULTS: We identified characteristic features of remodeling (BSM area >26.6%) and increased mitochondrial number within BSM in a subgroup of subjects with nonsevere asthma. The number of BSM mitochondria was positively correlated with BSM area (r = 0.78; P < 0.001). Follow-up analysis showed that subjects with asthma with high BSM had worse asthma control and a higher rate of exacerbations per year compared with subjects with low BSM. CONCLUSIONS: This study reveals that BSM remodeling and mitochondrial biogenesis may play a critical role in the natural history of nonsevere asthma (Mitasthme study). Clinical trial registered with www.clinicaltrials.gov (NCT00808730).

Blood fibrocytes are recruited during acute exacerbations of chronic obstructive pulmonary disease through a CXCR4-dependent pathway.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by peribronchial fibrosis. The chronic course of COPD is worsened by recurrent acute exacerbations. OBJECTIVE: The aim of the study was to evaluate the recruitment of blood fibrocytes in patients with COPD during exacerbations and, subsequently, to identify potential mechanisms implicated in such recruitment. METHODS: Using flow cytometry, we quantified circulating fibrocytes and characterized their chemokine receptor expression in 54 patients with COPD examined during an acute exacerbation (V1) and 2 months afterward (V2) and in 40 control subjects. The role of the chemokines CXCL12 and CCL11 in fibrocyte migration was investigated by using a chemotaxis assay. Patients were followed for up to 3 years after V1. RESULTS: We demonstrated a significantly increased number of circulating fibrocytes at V1 compared with control subjects. The number of circulating fibrocytes decreased at V2. A high percentage of circulating fibrocytes during exacerbation was associated with increased risk of death. The percentage of fibrocytes at V2 was negatively correlated with FEV1, forced vital capacity, FEV1/forced vital capacity ratio, transfer lung capacity of carbon monoxide, and Pao2. Fibrocytes highly expressed CXCR4 and CCR3, the chemokine receptors for CXCL12 and CCL11, respectively. Fibrocytes collected from patients with COPD at V1 had increased chemotactic migration in response to CXCL12 but not to CCL11 compared with those from control subjects. Plerixafor, a CXCR4 antagonist, decreased fibrocyte migration to plasma from patients with exacerbating COPD. CONCLUSION: Blood fibrocytes are recruited during COPD exacerbations and related to mortality and low lung function. The CXCL12/CXCR4 axis is involved in such fibrocyte recruitment (Firebrob study; ClinicalTrials NCT01196832).

Selective dysfunction of p53 for mitochondrial biogenesis induces cellular proliferation in bronchial smooth muscle from asthmatic patients.

BACKGROUND: Increase of bronchial smooth muscle (BSM) mass is a crucial feature of asthma remodeling. The mechanisms of such an increased BSM mass are complex but involve enhanced mitochondrial biogenesis, leading to increased proliferation of BSM cells in asthmatic patients. The major tumor suppressor protein p53 is a key cell regulator involved in cell proliferation and has also been implicated in mitochondrial biogenesis. However, the role of p53 in BSM cell proliferation and mitochondrial biogenesis has not been investigated thus far. OBJECTIVE: We sought to evaluate the role of p53 in proliferation of BSM cells in asthmatic patients and mitochondrial biogenesis. METHODS: The expression of p53 was assessed both in vitro by using flow cytometry and Western blotting and ex vivo by using RT-PCR after laser microdissection. The role of p53 was assessed with small hairpin RNA lentivirus in both asthmatic patients and control subjects with BSM cell proliferation by using 5-bromo-2'-deoxyuridine and cell counting and in the expression of p21, BCL2-associated X protein, mitochondrial transcription factor A (TFAM), and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α). RESULTS: Twenty-nine patients with moderate-to-severe asthma and 26 control subjects were enrolled in the study. p53 expression was increased in BSM from asthmatic patients both ex vivo and in vitro, with a decreased interaction with mouse double minute 2 homolog (Mdm2) and an increased phosphorylation of serine 20. p53 did not inhibit the transcription of both TFAM and PGC-1α in BSM cells from asthmatic patients. As a consequence, p53 is unable to slow the increased mitochondrial biogenesis and hence the subsequent increased proliferation of BSM cells in asthmatic patients. CONCLUSION: This study suggests that p53 might act as a new potential therapeutic target against BSM remodeling in asthmatic patients.

House dust mites induce proliferation of severe asthmatic smooth muscle cells via an epithelium-dependent pathway.

RATIONALE: Asthma is a frequent airway disease, and asthma control determinants have been associated with indoor allergen sensitization. The most frequent allergens are house dust mites (HDM), which act in vivo on the bronchial epithelial layer. Severe asthma has also been associated with bronchial remodeling and more specifically with increased mass of bronchial smooth muscle (BSM). However, the relationship between HDM stimulation of the bronchial epithelial layer and BSM remodeling is unknown. OBJECTIVES: To evaluate whether epithelial stimulation with HDM induces BSM cell proliferation in subjects with severe asthma. METHODS: A total of 22 subjects with severe asthma and 27 subjects with no asthma were recruited. We have developed an in vitro culture model combining an epithelium layer in air-liquid interface (ALI) interacting with BSM. We assessed BSM proliferation using BrdU incorporation. We explored the role of epithelium-derived mediators using reverse-transcriptase polymerase chain reaction (RT-PCR) and ELISA in vitro and in vivo. Finally, leukotrienes receptor expression was assessed in vitro by flow cytometry and RT-PCR and ex vivo by laser microdissection and RT-PCR. MEASUREMENTS AND MAIN RESULTS: We found that epithelial stimulation by HDM selectively increased the proliferation of asthmatic BSM cells and not that of nonasthmatic cells. The mechanism involved epithelial protease-activated receptor-2-dependent production of leukotrienes C4 associated with an overexpression of leukotrienes receptor CysLTR1 by asthmatic BSM cells in vitro and ex vivo. CONCLUSIONS: This work demonstrates the selective role of HDM on BSM remodeling in patients with severe asthma and points out different therapeutic targets at epithelial and smooth muscle levels.

Calcium channel blocker reduces airway remodeling in severe asthma. A proof-of-concept study.

RATIONALE: Severe asthma is a major public health issue throughout the world. Increased bronchial smooth muscle (BSM) mass, a characteristic feature of airway remodeling in severe asthma, is associated with resistance to high-intensity treatment and poor prognosis. In vitro, the Ca(2+)-channel blocker gallopamil decreased the proliferation of BSM cells from patients with severe asthma. OBJECTIVES: We conducted a double-blind, randomized, placebo-controlled study to evaluate the effect of gallopamil on airway remodeling in patients with severe asthma. METHODS: Subjects received either gallopamil (n = 16) or placebo (n = 15) for 1 year and were monitored for an additional 3-month period. Airway remodeling was analyzed at baseline and after treatment phase using both fiberoptic bronchoscopy and computed tomography scan. The primary end point was the BSM area. Secondary end points included normalized BSM thickness and frequency of asthma exacerbations. MEASUREMENTS AND MAIN RESULTS: BSM area was reduced in the gallopamil group (baseline vs. end of treatment) but was unchanged in the placebo group. Between-group differences in BSM area were not significantly different in gallopamil versus placebo groups. By contrast, between-group differences in normalized BSM thickness were significantly different between the two groups. The mean number of exacerbations per month was not different during the treatment phase in gallopamil versus placebo group but was significantly lower in patients previously treated with gallopamil during the follow-up period. There were no differences between the groups with respect to overall side effects. CONCLUSIONS: Gallopamil treatment for 12 months reduces BSM remodeling and prevents the occurrence of asthma exacerbations. Clinical trial registered with www.clinicaltrials.gov (NCT 00896428).

NGF increases Connexin-43 expression and function in pulmonary arterial smooth muscle cells to induce pulmonary artery hyperreactivity.

AIMS: Pulmonary hypertension (PH) is characterised by an increase in pulmonary arterial pressure, ultimately leading to right ventricular failure and death. We have previously shown that nerve growth factor (NGF) plays a critical role in PH. Our objectives here were to determine whether NGF controls Connexin-43 (Cx43) expression and function in the pulmonary arterial smooth muscle, and whether this mechanism contributes to NGF-induced pulmonary artery hyperreactivity. METHODS AND RESULTS: NGF activates its TrkA receptor to increase Cx43 expression, phosphorylation, and localization at the plasma membrane in human pulmonary arterial smooth muscle cells, thus leading to enhanced activity of Cx43-dependent GAP junctions as shown by Lucifer Yellow dye assay transfer and fluorescence recovery after photobleaching -FRAP- experiments. Using both in vitro pharmacological and in vivo SiRNA approaches, we demonstrate that NGF-dependent increase in Cx43 expression and activity in the rat pulmonary circulation causes pulmonary artery hyperreactivity. We also show that, in a rat model of PH induced by chronic hypoxia, in vivo blockade of NGF or of its TrkA receptor significantly reduces Cx43 increased pulmonary arterial expression induced by chronic hypoxia and displays preventive effects on pulmonary arterial pressure increase and right heart hypertrophy. CONCLUSIONS: Modulation of Cx43 by NGF in pulmonary arterial smooth muscle cells contributes to NGF-induced alterations of pulmonary artery reactivity. Since NGF and its TrkA receptor play a role in vivo in Cx43 increased expression in PH induced by chronic hypoxia, these NGF/Cx43-dependent mechanisms may therefore play a significant role in human PH pathophysiology.

Multicentre retrospective analysis on pulmonary metastasectomy: an European perspective.

OBJECTIVES: To assess the current practice of pulmonary metastasectomy at 15 European Centres. Short- and long-term outcomes were analysed. METHODS: Retrospective analysis on patients ≥18 years who underwent curative-intent pulmonary metastasectomy (January 2010 to December 2018). Data were collected on a purpose-built database (REDCap). Exclusion criteria were: previous lung/extrapulmonary metastasectomy, pneumonectomy, non-curative intent and evidence of extrapulmonary recurrence at the time of lung surgery. RESULTS: A total of 1647 patients [mean age 59.5 (standard deviation; SD = 13.1) years; 56.8% males] were included. The most common primary tumour was colorectal adenocarcinoma. The mean disease-free interval was 3.4 (SD = 3.9) years. Relevant comorbidities were observed in 53.8% patients, with a higher prevalence of metabolic disorders (32.3%). Video-assisted thoracic surgery was the chosen approach in 54.9% cases. Wedge resections were the most common operation (67.1%). Lymph node dissection was carried out in 41.4% cases. The median number of resected lesions was 1 (interquartile range 25-75% = 1-2), ranging from 1 to 57. The mean size of the metastases was 18.2 (SD = 14.1) mm, with a mean negative resection margin of 8.9 (SD = 9.4) mm. A R0 resection of all lung metastases was achieved in 95.7% cases. Thirty-day postoperative morbidity was 14.5%, with the most frequent complication being respiratory failure (5.6%). Thirty-day mortality was 0.4%. Five-year overall survival and recurrence-free survival were 62.0% and 29.6%, respectively. CONCLUSIONS: Pulmonary metastasectomy is a low-risk procedure that provides satisfactory oncological outcomes and patient survival. Further research should aim at clarifying the many controversial aspects of its daily clinical practice.

Role of YKL-40 in bronchial smooth muscle remodeling in asthma.

RATIONALE: Bronchial remodeling, including increased bronchial smooth muscle (BSM) mass, contributes to bronchial obstruction in asthma. However, its mechanisms are complex and remain controversial. Recently, a role of the chitinase 3-like 1 protein (YKL-40) has been evoked in asthma. Indeed, YKL-40 concentration was increased in asthmatic serum, and correlated with asthma severity and subepithelial membrane thickness. Nevertheless, the role of YKL-40 on BSM cells remains to be investigated. OBJECTIVES: To evaluate whether YKL-40 altered the physiologic properties of BSM cells in asthma in vitro and ex vivo. METHODS: We enrolled 40 subjects with asthma, 13 nonsmokers, and 16 smokers. BSM cells were derived from bronchial specimens obtained by either fiberoptic bronchoscopy or lobectomy. We assessed cell proliferation using BrdU, flow cytometry, and cell count; signaling intermediates using Western blot; cell migration using inserts, wound healing, and phalloidin staining; and cell synthesis using ELISA and Western blot. The involvement of protease activated receptor (PAR)-2 was evaluated using blocking antibody and dedicated lentiviral small hairpin RNA. We also determined the BSM area and the YKL-40 staining ex vivo using immunohistochemistry on biopsies from subjects with asthma and control subjects. MEASUREMENTS AND MAIN RESULTS: We demonstrated that YKL-40 increased BSM cell proliferation and migration through PAR-2-, AKT-, ERK-, and p38-dependent mechanisms. The increased cell migration was higher in BSM cells of subjects with asthma than that of control subjects. Furthermore, YKL-40 epithelial expression was positively correlated with BSM mass in asthma. CONCLUSIONS: This study indicates that YKL-40 promotes BSM cell proliferation and migration through a PAR-2-dependent mechanism.

Cardiopulmonary bypass during a second-lung implantation improves postoperative oxygenation after sequential double-lung transplantation.

OBJECTIVES: During sequential double-lung transplantation (DLT), the newly implanted first lung receives the entire cardiac output during the implantation of the second one. This may be responsible for the increased hydrostatic pressure that causes severe interstitial and alveolar edema that can lead to allograft dysfunction. The authors tested the hypothesis that CPB started after first graft implantation and before second recipient lung removal should improve post-transplantation oxygenation and clinical outcomes. DESIGN: Observational during 2 consecutive 1-year periods. SETTING: University hospital. PARTICIPANTS: Nine consecutive patients undergoing sequential DLT with CPB started after first graft implantation and before second recipient lung removal were compared to controls, who were 10 consecutive patients who underwent sequential DLT but without CPB the year before. MEASUREMENTS AND MAIN RESULTS: Oxygenation after transplantation was assessed. The use of CPB during the implantation of the second lung was associated with an increased mean postoperative ratio of PaO2 to the fraction of inspired oxygen at 1 hour (363±51 v 240±113, p = 0.01) and 6 hours (430±111 v 280±103, p = 0.03). The mean duration of CPB was 111±19 min. The occurrence of primary graft dysfunction and the need for extracorporeal membrane oxygenation tended to be lower, but did not reach significance. Similarly, mortality rate was comparable between both groups, as was the rate of blood transfusions. CONCLUSIONS: The authors' results suggest that the use of CPB started after first graft implantation and before second recipient lung removal appears to benefit oxygenation and reduces the occurrence of severe pulmonary edema in the first transplanted lung.

Prediction of survival after a lung transplant at 1 year (SALTO cohort) using information available at different key time points.

OBJECTIVES: A lung transplant is the final treatment option for end-stage lung disease. We evaluated the individual risk of 1-year mortality at each stage of the lung transplant process. METHODS: This study was a retrospective analysis of patients undergoing bilateral lung transplants between January 2014 and December 2019 in 3 French academic centres. Patients were randomly divided into development and validation cohorts. Three multivariable logistic regression models of 1-year mortality were applied (i) at recipient registration, (ii) the graft allocation and (iii) after the operation. The 1-year mortality was predicted for individual patients assigned to 3 risk groups at time points A to C. RESULTS: The study population consisted of 478 patients with a mean (standard deviation) age of 49.0 (14.3) years. The 1-year mortality rate was 23.0%. There were no significant differences in patient characteristics between the development (n = 319) and validation (n = 159) cohorts. The models analysed recipient, donor and intraoperative variables. The discriminatory power (area under the receiver operating characteristic curve) was 0.67 (0.62-0.73), 0.70 (0.63-0.77) and 0.82 (0.77-0.88), respectively, in the development cohort and 0.74 (0.64-0.85), 0.76 (0.66-0.86) and 0.87 (0.79 - 0.95), respectively, in the validation cohort. Survival rates were significantly different among the low- (< 15%), intermediate- (15%-45%) and high-risk (> 45%) groups in both cohorts. CONCLUSIONS: Risk prediction models allow estimation of the 1-year mortality risk of individual patients during the lung transplant process. These models may help caregivers identify high-risk patients at times A to C and reduce the risk at subsequent time points.

Short-range interactions between fibrocytes and CD8+ T cells in COPD bronchial inflammatory response.

Bronchi of chronic obstructive pulmonary disease (COPD) are the site of extensive cell infiltration, allowing persistent contact between resident cells and immune cells. Tissue fibrocytes interaction with CD8+ T cells and its consequences were investigated using a combination of in situ, in vitro experiments and mathematical modeling. We show that fibrocytes and CD8+ T cells are found in the vicinity of distal airways and that potential interactions are more frequent in tissues from COPD patients compared to those of control subjects. Increased proximity and clusterization between CD8+ T cells and fibrocytes are associated with altered lung function. Tissular CD8+ T cells from COPD patients promote fibrocyte chemotaxis via the CXCL8-CXCR1/2 axis. Live imaging shows that CD8+ T cells establish short-term interactions with fibrocytes, that trigger CD8+ T cell proliferation in a CD54- and CD86-dependent manner, pro-inflammatory cytokines production, CD8+ T cell cytotoxic activity against bronchial epithelial cells and fibrocyte immunomodulatory properties. We defined a computational model describing these intercellular interactions and calibrated the parameters based on our experimental measurements. We show the model's ability to reproduce histological ex vivo characteristics, and observe an important contribution of fibrocyte-mediated CD8+ T cell proliferation in COPD development. Using the model to test therapeutic scenarios, we predict a recovery time of several years, and the failure of targeting chemotaxis or interacting processes. Altogether, our study reveals that local interactions between fibrocytes and CD8+ T cells could jeopardize the balance between protective immunity and chronic inflammation in the bronchi of COPD patients.

Immersive Three-dimensional Computed Tomography to Plan Chest Wall Resection for Lung Cancer.

PURPOSE: Chest wall resections for lung cancer treatment remain difficult to plan using standard 2-dimensional computed tomography. Although virtual reality headsets have been used in many medical contexts, they have not been used in chest wall resection planning. DESCRIPTION: We compared preoperative planning of a chest wall surgical resection for lung cancer treatment between senior and resident surgeons who used an immersive virtual reality device and a 2-dimensional computed tomography. EVALUATION: Chest wall resection planning was more accurate when surgeons used virtual reality vs computed tomography analysis (28.6% vs 18.3%, P = .018), and this was particularly true in the resident surgeon group (27.4% vs 8.3%, P = .0025). Predictions regarding the need for chest wall substitutes were also more accurate when they were made using virtual reality vs computed tomography analysis in all groups (96% vs 68.5%, P < .0001). Other studied parameters were not affected by the use of the virtual reality tool. CONCLUSIONS: Virtual reality may offer enhanced accuracy for chest wall resection and reconstruction planning for lung cancer treatment.

Asthmatic bronchial smooth muscle increases rhinovirus replication within the bronchial epithelium.

Rhinovirus (RV) infection of the bronchial epithelium is implicated in the vast majority of severe asthma exacerbations. Interestingly, the susceptibility of bronchial epithelium to RV infection is increased in persons with asthma. Bronchial smooth muscle (BSM) remodeling is an important feature of severe asthma pathophysiology, and its reduction using bronchial thermoplasty has been associated with a significant decrease in the exacerbation rate. We hypothesized that asthmatic BSM can play a role in RV infection of the bronchial epithelium. Using an original co-culture model between bronchial epithelium and BSM cells, we show that asthmatic BSM cells increase RV replication in bronchial epithelium following RV infection. These findings are related to the increased production of CCL20 by asthmatic BSM cells. Moreover, we demonstrate an original downregulation of the activity of the epithelial protein kinase RNA-activated (PKR) antiviral pathway. Finally, we identify a direct bottom-up effect of asthmatic BSM cells on bronchial epithelium susceptibility to RV infection.