The reproducibility and responsiveness of the lung clearance index in bronchiectasis

Lung clearance index (LCI) is a potential clinical outcome marker in bronchiectasis. Its responsiveness to therapeutic intervention has not been determined. This study evaluates its responsiveness to a session of physiotherapy and intravenous antibiotic treatment of an exacerbation.

32 stable and 32 exacerbating bronchiectasis patients and 26 healthy controls were recruited. Patients had LCI and lung function performed before and after physiotherapy on two separate occasions in the stable patients and at the beginning and end of an intravenous antibiotic course in the exacerbating patients.

LCI was reproducible between visits in 25 stable patients, with an intraclass correlation of 0.978 (0.948, 0.991; p<0.001). There was no significant difference in LCI (mean±sd) between stable 11.91±3.39 and exacerbating patients 12.76±3.47, but LCI was significantly higher in both bronchiectasis groups compared with healthy controls (7.36±0.99) (p<0.001). Forced expiratory volume in 1 s improved after physiotherapy, as did alveolar volume after intravenous antibiotics, but LCI did not change significantly.

LCI is reproducible in stable bronchiectasis but unlike conventional lung function tests, is unresponsive to two short-term interventions and hence is unlikely to be a useful clinical tool for short-term acute assessment in these patients. Further evaluation is required to establish its role in milder disease and in the evaluation of long-term interventions.

Chronic Infection by Mucoid Pseudomonas aeruginosa Associated with Dysregulation in T-Cell Immunity to Outer Membrane Porin F

RATIONALE

Pseudomonas aeruginosa (PA) is an environmental pathogen that commonly infects individuals with cystic fibrosis (CF) and non-CF bronchiectasis, impacting morbidity and mortality. To understand the pathobiology of interactions between the bacterium and host adaptive immunity and to inform rational vaccine design, it is important to understand the adaptive immune correlates of disease.

OBJECTIVES

To characterize T-cell immunity to the PA antigen outer membrane porin F (OprF) by analyzing immunodominant epitopes in relation to infection status.

METHODS

Patients with non-CF bronchiectasis were stratified by frequency of PA isolation. T-cell IFN-γ immunity to OprF and its immunodominant epitopes was characterized. Patterns of human leukocyte antigen (HLA) restriction of immunodominant epitopes were defined using HLA class II transgenic mice. Immunity was characterized with respect to cytokine and chemokine secretion, antibody response, and T-cell activation transcripts.

MEASUREMENTS AND MAIN RESULTS

Patients were stratified according to whether PA was never, sometimes (<50%), or frequently (≥50%) isolated from sputum. Patients with frequent PA sputum-positive isolates were more likely to be infected by mucoid PA, and they showed a narrow T-cell epitope response and a relative reduction in Th1 polarizing transcription factors but enhanced immunity with respect to antibody production, innate cytokines, and chemokines.

CONCLUSIONS

We have defined the immunodominant, HLA-restricted T-cell epitopes of OprF. Our observation that chronic infection is associated with a response of narrowed specificity, despite strong innate and antibody immunity, may help to explain susceptibility in these individuals and pave the way for better vaccine design to achieve protective immunity.

Evidence of mycobacterial disease in COPD patients with lung volume reduction surgery; the importance of histological assessment of specimens: a cohort study

Background

Patients with COPD are at risk of non-tuberculous mycobacterial infection (NTM). This study examined the histology of lung tissue from COPD patients following lung volume reduction with particular focus on evidence of mycobacterial infection.

Methods

Retrospective histological study of 142 consecutive lung volume reduction surgical specimens (126 separate patients) at Royal Brompton Hospital between 2000 – 2013, with prospectively collected preoperative data on exacerbation rate, lung function and body mass index.

Results

92% of patients had at least one other histological diagnosis in addition to emphysema. 10% of specimens had histological evidence of mycobacterial infection, one with co-existent aspergilloma. Mycobacteria were only identified in those patients with granulomas that were necrotising. These patients had higher exacerbation rates, lower TLCO and FEV₁.

Conclusion

A proportion of severe COPD patients will have evidence of mycobacterial infection despite lack of clinical and radiological suspicion. This may have implications for long-term management of these patients.

BIIL 284 reduces neutrophil numbers but increases P. aeruginosa bacteremia and inflammation in mouse lungs

BACKGROUND

A clinical study to investigate the leukotriene B(4) (LTB(4))-receptor antagonist BIIL 284 in cystic fibrosis (CF) patients was prematurely terminated due to a significantly increased risk of adverse pulmonary events. We aimed to establish the effect of BIIL284 in models of Pseudomonas aeruginosa lung infection, thereby contributing to a better understanding of what could have led to adverse pulmonary events in CF patients.

METHODS

P. aeruginosa DNA in the blood of CF patients during and after acute pulmonary exacerbations and in stable patients with non-CF bronchiectasis (NCFB) and healthy individuals was assessed by PCR. The effect of BIIL 284 treatment was tested in an agar bead murine model of P. aeruginosa lung infection. Bacterial count and inflammation were evaluated in lung and other organs.

RESULTS

Most CF patients (98%) and all patients with NCFB and healthy individuals had negative P. aeruginosa DNA in their blood. Similarly, the P. aeruginosa-infected mice showed bacterial counts in the lung but not in the blood or spleen. BIIL 284 treatment decreased pulmonary neutrophils and increased P. aeruginosa numbers in mouse lungs leading to significantly higher bacteremia rates and lung inflammation compared to placebo treated animals.

CONCLUSIONS

Decreased airway neutrophils induced lung proliferation and severe bacteremia in a murine model of P. aeruginosa lung infection. These data suggest that caution should be taken when administering anti-inflammatory compounds to patients with bacterial infections.

Stem cells as vectors for antitumour therapy

Recent research suggests that mesenchymal stem cells (MSCs) are able to migrate specifically to tumours and their metastases throughout the body. This has led to considerable excitement about the possibility of modifying these cells to express anticancer molecules and using them as specific targeted anticancer agents. However, there are concerns that systemically delivered MSCs may have non-desirable effects, and there are also many unanswered questions including the mechanism of tumour homing. This review investigates the different MSC-delivered anticancer agents, addresses the questions and concerns, and tries to place this potential therapy in future cancer management.

Upper airway 2: Bronchiectasis, cystic fibrosis and sinusitis

The nose and paranasal sinuses are contiguous with the lower respiratory tract. Patients with bronchiectasis and cystic fibrosis commonly have sinonasal disease, which is thought to have the same aetiology and pathophysiology as the chronic lung disease. Despite this, the conditions are rarely considered together and there is very little literature on the treatment of sinonasal disease in bronchiectasis. In addition to being a common cause of comorbidity, there is evidence suggesting that sinonasal disease may directly influence the bronchial condition. This article reviews sinonasal disease in bronchiectasis and cystic fibrosis and addresses the possible interactions between the health and disease of the upper and lower airways.

Magnetic resonance imaging of mesenchymal stem cells homing to pulmonary metastases using biocompatible magnetic nanoparticles

The ability of mesenchymal stem cells (MSC) to specifically home to tumors has suggested their potential use as a delivery vehicle for cancer therapeutics. MSC integration into tumors has been shown in animal models using histopathologic techniques after animal sacrifice. Tracking the delivery and engraftment of MSCs into human tumors will need in vivo imaging techniques. We hypothesized that labeling MSCs with iron oxide nanoparticles would enable in vivo tracking with magnetic resonance imaging (MRI). Human MSCs were labeled in vitro with superparamagnetic iron oxide nanoparticles, with no effect on differentiation potential, proliferation, survival, or migration of the cells. In initial experiments, we showed that as few as 1,000 MSCs carrying iron oxide nanoparticles can be detected by MRI one month after their coinjection with breast cancer cells that formed subcutaneous tumors. Subsequently, we show that i.v.- injected iron-labeled MSCs could be tracked in vivo to multiple lung metastases using MRI, observations that were confirmed histologically. This is the first study to use MRI to track MSCs to lung metastases in vivo. This technique has the potential to show MSC integration into human tumors, allowing early-phase clinical studies examining MSC homing in patients with metastatic tumors.

Mesenchymal stem cell delivery of TRAIL can eliminate metastatic cancer

Cancer is a leading cause of mortality throughout the world and new treatments are urgently needed. Recent studies suggest that bone marrow-derived mesenchymal stem cells (MSC) home to and incorporate within tumor tissue. We hypothesized that MSCs engineered to produce and deliver tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a transmembrane protein that causes selective apoptosis of tumor cells, would home to and kill cancer cells in a lung metastatic cancer model. Human MSCs were transduced with TRAIL and the IRES-eGFP reporter gene under the control of a tetracycline promoter using a lentiviral vector. Transduced and activated MSCs caused lung (A549), breast (MDAMB231), squamous (H357), and cervical (Hela) cancer cell apoptosis and death in coculture experiments. Subcutaneous xenograft experiments confirmed that directly delivered TRAIL-expressing MSCs were able to significantly reduce tumor growth [0.12 cm(3) (0.04-0.21) versus 0.66 cm(3) (0.21-1.11); P < 0.001]. We then found, using a pulmonary metastasis model, systemically delivered MSCs localized to lung metastases and the controlled local delivery of TRAIL completely cleared the metastatic disease in 38% of mice compared with 0% of controls (P < 0.05). This is the first study to show a significant reduction in metastatic tumor burden with frequent eradication of metastases using inducible TRAIL-expressing MSCs. This has a wide potential therapeutic role, which includes the treatment of both primary tumors and their metastases, possibly as an adjuvant therapy in clearing micrometastatic disease following primary tumor resection.

Mortality in bronchiectasis: a long-term study assessing the factors influencing survival

There is little literature about the mortality associated with bronchiectasis. The aim of the present study was to investigate factors affecting mortality in patients with bronchiectasis. In total, 91 patients were examined for aetiology, pulmonary function tests, high-resolution computed tomography, sputum microbiology and quality of life scores and were then followed over 13 yrs. Overall, 29.7% of the patients died. On multivariate analysis, age, St George's Respiratory Questionnaire activity score, Pseudomonas aeruginosa infection, total lung capacity (TLC), residual volume/TLC and the transfer factor coefficient were all independently associated with mortality. In patients with moderate to severe bronchiectasis, mortality is associated with a degree of restrictive and obstructive disease, poor gas transfer and chronic pseudomonas infection. These features should guide future research into disease progression, and identify those patients needing intensive treatment.

Procalcitonin in stable and unstable patients with bronchiectasis

Presently used markers of infection in bronchiectasis are inadequate to judge stability or make decisions about antibiotic treatment during bacterial exacerbations. Procalcitonin (PCT) is a new marker that has been used in community-acquired pneumonia and promises to allow much more specific and sensitive monitoring of patients with bacterial infections. This is the first study assessing its use in bronchiectasis. Thirty-eight consecutive inpatients and 63 consecutive outpatients were included in the study. All patients had PCT, other inflammatory markers, and a symptom score recorded. Inpatients had these values repeated at day 5 and 10 of their stay, while receiving intravenous antibiotics. Outpatients: PCT levels were generally low in the outpatient group. PCT was significantly correlated to C-reactive protein. Higher levels were associated with increased symptoms (P = 0.09) and an increased likelihood of antibiotic prescription (P = 0.007). Inpatients: As a group, inflammatory markers were significantly higher than in the outpatient group (P = 0.007). There was no correlation between the levels of PCT and the other inflammatory markers. PCT concentrations were generally low (as with other markers), which may reflect mucosal infection. Larger studies are needed, but PCT seems unlikely to be able to guide treatment of an exacerbation in bronchiectasis. PCT may offer more promise as a measure of stability.

Stem Cells for Lung Disease

Respiratory diseases remain one of the main causes of morbidity and mortality in the world. Interest has increased as to the possibility of optimizing the repair of the lung with the manipulation of stem cells. Embryonic and adult stem cells have been suggested as possibilities. Adult stem cells have traditionally been thought of as having limited differentiation ability and to be organ specific. However, a series of exciting reports over the last 5 to 10 years have suggested that adult bone marrow-derived stem cells may have more plasticity and are able to differentiate into bronchial and alveolar epithelium, vascular endothelium, and interstitial cell types, making them prime candidates for repair. This article critically reviews the evidence for this plasticity and the use of predominantly adult stem cells to help with lung regeneration and repair and assesses how this technology may be utilized in clinical medicine.