Oriol Sibila

The first tissue-engineered airway transplantation: 5-year follow-up results

BACKGROUND In 2008, the first transplantation of a tissue-engineered trachea in a human being was done to replace an end-staged left main bronchus with malacia in a 30-year-old woman. We report 5 year follow-up results. METHODS The patient was followed up approximately every 3 months with multidetector CT scan and bronchoscopic assessment. We obtained mucosal biopsy samples every 6 months for histological, immunohistochemical, and electron microscopy assessment. We also assessed quality of life, respiratory function, cough reflex test, and production and specificity of recipient antibodies against donor human leucocyte antigen. FINDINGS By 12 months after transplantation, a progressive cicatricial stenosis had developed in the native trachea close to the tissue-engineered trachea anastomosis, which needed repeated endoluminal stenting. However, the tissue-engineered trachea itself remained open over its entire length, well vascularised, completely re-cellularised with respiratory epithelium, and had normal ciliary function and mucus clearance. Lung function and cough reflex were normal. No stem-cell-related teratoma formed and no anti-donor antibodies developed. Aside from intermittent bronchoscopic interventions, the patient had a normal social and working life. INTERPRETATION These clinical results provide evidence that a tissue-engineering strategy including decellularisation of a human trachea, autologous epithelial and stem-cell culture and differentiation, and cell-scaffold seeding with a bioreactor is safe and promising. FUNDING European Commission, Knut and Alice Wallenberg Foundation, Swedish Research Council, ALF Medicine.

Effect of corticosteroids on treatment failure among hospitalized patients with severe community-acquired pneumonia and high inflammatory response: a randomized clinical trial.

IMPORTANCE In patients with severe community-acquired pneumonia, treatment failure is associated with excessive inflammatory response and worse outcomes. Corticosteroids may modulate cytokine release in these patients, but the benefit of this adjunctive therapy remains controversial. OBJECTIVE To assess the effect of corticosteroids in patients with severe community-acquired pneumonia and high associated inflammatory response. DESIGN, SETTING, AND PARTICIPANTS Multicenter, randomized, double-blind, placebo-controlled trial conducted in 3 Spanish teaching hospitals involving patients with both severe community-acquired pneumonia and a high inflammatory response, which was defined as a level of C-reactive protein greater than 150 mg/L at admission. Patients were recruited and followed up from June 2004 through February 2012. INTERVENTIONS Patients were randomized to receive either an intravenous bolus of 0.5 mg/kg per 12 hours of methylprednisolone (n = 61) or placebo (n = 59) for 5 days started within 36 hours of hospital admission. MAIN OUTCOMES AND MEASURES The primary outcome was treatment failure (composite outcome of early treatment failure defined as [1] clinical deterioration indicated by development of shock, [2] need for invasive mechanical ventilation not present at baseline, or [3] death within 72 hours of treatment; or composite outcome of late treatment failure defined as [1] radiographic progression, [2] persistence of severe respiratory failure, [3] development of shock, [4] need for invasive mechanical ventilation not present at baseline, or [5] death between 72 hours and 120 hours after treatment initiation; or both early and late treatment failure). In-hospital mortality was a secondary outcome and adverse events were assessed. RESULTS There was less treatment failure among patients from the methylprednisolone group (8 patients [13%]) compared with the placebo group (18 patients [31%]) (P = .02), with a difference between groups of 18% (95% CI, 3% to 32%). Corticosteroid treatment reduced the risk of treatment failure (odds ratio, 0.34 [95% CI, 0.14 to 0.87]; P = .02). In-hospital mortality did not differ between the 2 groups (6 patients [10%] in the methylprednisolone group vs 9 patients [15%] in the placebo group; P = .37); the difference between groups was 5% (95% CI, -6% to 17%). Hyperglycemia occurred in 11 patients (18%) in the methylprednisolone group and in 7 patients (12%) in the placebo group (P = .34). CONCLUSIONS AND RELEVANCE Among patients with severe community-acquired pneumonia and high initial inflammatory response, the acute use of methylprednisolone compared with placebo decreased treatment failure. If replicated, these findings would support the use of corticosteroids as adjunctive treatment in this clinical population. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00908713.

Effects of glucocorticoids in ventilated piglets with severe pneumonia

There is clinical evidence suggesting that glucocorticoids may be useful in severe pneumonia, but the pathogenic mechanisms explaining these beneficial effects are unknown. The aim of the present study was to determine the effects of adding glucocorticoids to antibiotic treatment in an experimental model of severe pneumonia. In total, 15 Lagerwhite-Landrace piglets were ventilated for 96 h. After intubation, a 75 mL solution containing Pseudomonas aeruginosa (106 cfu·mL−1) was bronchoscopically inoculated. The animals were randomised into three groups 12 h after inoculation: 1) untreated; 2) treated with ciprofloxacin; and 3) treated with ciprofloxacin plus methylprednisolone. Physiological and laboratory parameters were monitored throughout the study. Pro-inflammatory cytokines were measured in serum and bronchoalveolar lavage (BAL). Histopathology of the lungs and cultures from blood, BAL and lungs were performed. At the end of the study, piglets receiving the antibiotic plus glucocorticoids showed: 1) a decrease in the concentration of interleukin-6 in BAL; and 2) a decrease in the global bacterial burden both in BAL and lung tissue. In conclusion, in this experimental model of pneumonia, the association of glucocorticoids with antibiotics attenuates local inflammatory response and decreases bacterial burden in the lung.

Neutrophil Elastase Activity is Associated with Exacerbations and Lung Function Decline in Bronchiectasis

Rationale: Sputum neutrophil elastase and serum desmosine, which is a linked marker of endogenous elastin degradation, are possible biomarkers of disease severity and progression in bronchiectasis. This study aimed to determine the association of elastase activity and desmosine with exacerbations and lung function decline in bronchiectasis. Methods: This was a single‐center prospective cohort study using the TAYBRIDGE (Tayside Bronchiectasis Registry Integrating Datasets, Genomics, and Enrolment into Clinical Trials) registry in Dundee, UK. A total of 433 patients with high‐resolution computed tomography‐confirmed bronchiectasis provided blood samples for desmosine measurement, and 381 provided sputum for baseline elastase activity measurements using an activity‐based immunosassay and fluorometric substrate assay. Candidate biomarkers were tested for their relationship with cross‐sectional markers of disease severity, and with future exacerbations, mortality and lung function decline over 3 years. Measurement and Main Results: Elastase activity in sputum was associated with the bronchiectasis severity index (r = 0.49; P < 0.0001) and was also correlated with the Medical Research Council dyspnea score (r = 0.34; P < 0.0001), FEV1% predicted (r = −0.33; P < 0.0001), and the radiological extent of bronchiectasis (r = 0.29; P < 0.0001). During a 3‐year follow‐up, elevated sputum elastase activity was associated with a higher frequency of exacerbations (P < 0.0001) but was not independently associated with mortality. Sputum elastase activity was independently associated with FEV1 decline (&bgr; coefficient, −0.139; P = 0.001). Elastase showed good discrimination for severe exacerbations with an area under the curve of 0.75 (95% confidence interval [CI], 0.72‐0.79) and all‐cause mortality (area under the curve, 0.70; 95% CI, 0.67‐0.73). Sputum elastase activity increased at exacerbations (P = 0.001) and was responsive to treatment with antibiotics. Desmosine was correlated with sputum elastase (r = 0.42; P < 0.0001) and was associated with risk of severe exacerbations (hazard ratio 2.7; 95% CI, 1.42‐5.29; P = 0.003) but not lung function decline. Conclusions: Sputum neutrophil elastase activity is a biomarker of disease severity and future risk in adults with bronchiectasis.

Personalized Respiratory Medicine: Exploring the Horizon, Addressing the Issues. Summary of a BRN-AJRCCM Workshop Held in Barcelona on June 12, 2014

This Pulmonary Perspective summarizes the content and main conclusions of an international workshop on personalized respiratory medicine coorganized by the Barcelona Respiratory Network ( www.brn.cat ) and the AJRCCM in June 2014. It discusses (1) its definition and historical, social, legal, and ethical aspects; (2) the view from different disciplines, including basic science, epidemiology, bioinformatics, and network/systems medicine; (3) the bottlenecks and opportunities identified by some currently ongoing projects; and (4) the implications for the individual, the healthcare system and the pharmaceutical industry. The authors hope that, although it is not a systematic review on the subject, this document can be a useful reference for researchers, clinicians, healthcare managers, policy-makers, and industry parties interested in personalized respiratory medicine.

Animal models of ventilator-associated pneumonia

Animal models are an essential step between “in vitro” testing and clinical studies. Different animal models have been useful for the study of pathophysiology, diagnosis and therapy in ventilator-associated pneumonia (VAP). Aspiration has been studied in dog and cat models and bacteriological diagnosis has been evaluated in baboons. Pigs have been used for studying either spontaneous or induced VAP. Intubated piglets in prone position were administered analgesia and muscle paralysis was induced, and the intubated piglets underwent mechanical ventilation for several days. In this model, spontaneous VAP due to common bacterial pig colonisation develops within a few days. Pneumonia can also be induced by inoculating high concentrations of microorganisms (Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus). Different clinical, physiological, microbiological and pathological parameters of infection have been studied in this model. In addition, administration of antibiotics and inflammatory modulators and their consequences in microbiological eradication and local and systemic inflammation have been evaluated with interesting translational results. Although bronchial inoculation of healthy subjects does not resemble the common pathophysiological mechanisms, the experimental model of ventilator-associated pneumonia induced by the inoculation of high concentrations of microorganisms in mechanically ventilated piglets is useful for the study of the local and systemic responses of lung infection and for the determination of potential measures of prevention or therapeutic modulation.

The microbiome in respiratory medicine: Current challenges and future perspectives

The healthy lung has previously been considered to be a sterile organ because standard microbiological culture techniques consistently yield negative results. However, culture-independent techniques report that large numbers of microorganisms coexist in the lung. There are many unknown aspects in the field, but available reports show that the lower respiratory tract microbiota: 1) is similar in healthy subjects to the oropharyngeal microbiota and dominated by members of the Firmicutes, Bacteroidetes and Proteobacteria phyla; 2) shows changes in smokers and well-defined differences in chronic respiratory diseases, although the temporal and spatial kinetics of these changes are only partially known; and 3) shows relatively abundant non-cultivable bacteria in chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, cystic fibrosis and bronchiectasis, with specific patterns for each disease. In all of these diseases, a loss of diversity, paralleled by an over-representation of Proteobacteria (dysbiosis), has been related to disease severity and exacerbations. However, it is unknown whether dysbiosis is a cause or a consequence of the damage to bronchoalveolar surfaces. Finally, little is known about bacterial functionality and the interactions between viruses, fungi and bacteria. It is expected that future research in bacterial gene expressions, metagenomics longitudinal analysis and host–microbiome animal models will help to move towards targeted microbiome interventions in respiratory diseases. The respiratory system bacterial community is dominated by specific phyla that change in chronic respiratory diseases http://ow.ly/j68Z30967DB

Corticosteroids in severe pneumonia

The mortality rate in severe community- or hospital-acquired pneumonia is very high, ranging 20–50%. Despite advances in antimicrobial therapy and supportive measures, this rate has not changed in recent years, suggesting that other factors are also responsible for the poor outcome. An abnormal increase in the local and systemic inflammatory response is associated with poor outcome, and this occurs despite adequate antibiotic therapy. There is evidence that acute administration of corticosteroids decreases the inflammatory response and might decrease mortality in severe pneumonia. This has been shown in one small randomised controlled study, terminated prematurely due to 0% mortality in the intervention arm. In addition, an experimental study showed that glucocorticosteroids decrease lung inflammatory response and lung bacterial burden, confirming the results obtained through in vitro investigations. Although these results are promising and suggest a novel role of glucocorticosteroids in pneumonia, the inherent risks and potential side-effects of these drugs require further controlled clinical trials in order to better define the target population before their general use in clinical practice. Specifically, dosage, period of administration, titration, tapering and side-effects are some of the key questions that need to be investigated.

Experimental Pseudomonas aeruginosa pneumonia: evaluation of the associated inflammatory response

An abnormal inflammatory response (IR) in pneumonia is associated with poor outcomes and high mortality. Animal models could help to better understand the relationship between the pulmonary infection and the associated IR. The aims of the present study were to validate an experimental model of pneumonia induced by the inoculation of Pseudomonas aeruginosa in ventilated piglets and to study the associated IR over a long period of time (96 h). Five Lagerwhite–Landrace piglets were ventilated for 4 days. After intubation, a solution containing 75 mL of P. aeruginosa (106 colony-forming units·mL−1) was bronchoscopically inoculated. Physiological and laboratory parameters were monitored throughout the study. Pro-inflammatory cytokines were measured in serum and in bronchoalveolar lavage (BAL). Histopathology of the lungs and cultures from blood, BAL and lungs were performed. All the animals developed histopathological evidence of pneumonia. Microbiological studies of both BAL and lung confirmed the presence of P. aeruginosa in all the samples. Throughout the study, an increase in interleukin-6 was observed in serum and in BAL. In conclusion, the experimental model of pneumonia induced by the inoculation of high concentrations of Pseudomonas aeruginosa in ventilated piglets is feasible and could be appropriate for the evaluation of different aspects of the associated inflammatory response.

Identification of airway bacterial colonization by an electronic nose in Chronic Obstructive Pulmonary Disease

BACKGROUND Airway bacterial colonization by potentially pathogenic microorganisms occurs in a proportion of patients with Chronic Obstructive Pulmonary Disease (COPD). It increases airway inflammation and influences outcomes negatively. Yet, its diagnosis in clinical practice is not straightforward. The electronic nose is a new non-invasive technology capable of distinguishing volatile organic compound (VOC) breath-prints in exhaled breath. We aim to explore if an electronic nose can reliably discriminate COPD patients with and without airway bacterial colonization. METHODS We studied 37 clinically stable COPD patients (67.8 ± 5.2 yrs, FEV1 41 ± 10% ref.) and 13 healthy controls (62.8 ± 5.2 yrs, FEV1 99 ± 10% ref.). The presence of potentially pathogenic microorganisms in the airways of COPD patients (n = 10, 27%) was determined using quantitative bacterial cultures of protected specimen brush. VOCs breath-prints were analyzed by discriminant analysis on principal component reduction, resulting in cross-validated accuracy values. Area Under Receiver Operating Characteristics (AUROC) was calculated using multiple logistic regression. RESULTS Demographic, functional and clinical characteristics were similar in colonized and non-colonized COPD patients but their VOC breath-prints were different (accuracy 89%, AUROC 0.92, p > 0.0001). Likewise, VOCs breath-prints from colonized (accuracy 88%, AUROC 0.98, p < 0.0001) and non-colonized COPD patients (accuracy 83%, AUROC 0.93, p < 0.0001) were also different from controls. CONCLUSIONS An electronic nose can identify the presence of airway bacterial colonization in clinically stable patients with COPD.