Regulation of Inflammatory Mediators in Chronic Obstructive Pulmonary Disease
Condition: COPD; Emphysema
MeSH terms: Lung Diseases, Obstructive; Pulmonary Disease, Chronic Obstructive; Emphysema
Study type: Observational

Summary: 
      The aim of this study is to investigate the mechanisms whereby lung function is decreased in
      COPD. The hypothesis is that in diseases such as COPD, inflammatory cells including
      neutrophils, macrophages and lymphocytes migrate to the lung and release either more or
      different types of inflammatory mediators and/or destructive enzymes compared to subjects
      without COPD. We aim to investigate these separate cell types in the blood of subjects with
      COPD and identify which genes are more highly expressed when compared to cells obtained from
      patients without COPD. We will also investigate the lung macrophages from these subjects to
      identify whether the same or different genes are expressed in these cells. We will isolate
      different leukocyte populations from the blood and extract ribonucleic acid (RNA) from these
      samples. The type and quantity of RNA in these samples is a reflection of the specific genes
      expressed in these cells. This RNA will be sent to Gene Logic and this company will test
      these samples to identify which genes have been expressed. Similar experiments will be
      performed using macrophages obtained following bronchoalveolar lavage of these subjects. We
      would aim to examine the responses of leukocytes from three groups of subjects, namely (i)
      non-smoking controls (ii) smokers without clinical or histological signs of COPD and (iii)
      smokers with COPD. The isolated leukocytes will either be immediately solubilized in
      solutions to purify RNA or we will then use these isolated cells in vitro and following
      stimulation investigate whether different genes are expressed or at a differential rate in
      the disease state. The objective is to identify which genes are specifically expressed in
      patients with COPD with a view to identify novel targets for drug therapy. We will examine
      both leukocytes derived from peripheral blood and macrophages obtained from bronchoalveolar
      lavage with the aim to determine whether differences attributable to disease can be
      identified in both circulating cells and those at the site of disease. This is a preliminary
      study to determine the profile of inflammatory mediator expression from leukocytes and as
      such power calculations to determine the number of subjects is not appropriate.
    

Detailed description: 
      This study involves a comparison of the inflammatory responses of leukocytes derived from 3
      separate subject groups. The aim of the study is to compare the responses of leukocytes from
      patients with COPD with subjects that smoke and healthy non-smokers. One part of the study
      will involve isolation of different leukocyte populations from blood from each of the subject
      groups. In a second part of the study, we will examine the expression of inflammatory
      mediators in leukocytes derived from bronchoalveolar lavage samples from patients with COPD,
      smokers without COPD and healthy non-smokers. In subjects that are willing to participate, we
      will compare blood derived leukocytes and cells derived from those undergoing BAL, although
      not every subject will provide both blood and BAL samples. The isolated leukocytes (both from
      blood and BAL) will be used for in vitro experiments to determine the differences in gene
      expression in inflammatory cells from patients with COPD.

      Details of interventions to subjects

        1. Medical History and Physical Examination A full medical history and physical examination
           (including height and weight) will be performed on the initial screening visit, in
           addition to that recorded in the clinical case notes.

        2. Respiratory Assessments Forced Expiratory Volume per second (FEVI) will be measured
           using a dry wedge spirometer (Vitalograph, Buckingham, UK) and expressed as a percent of
           predicted value. Subjects will be trained in the use of the apparatus before beginning
           the study. The baseline value at each visit will be measured after at least fifteen
           minutes of quiet rest, and will be taken as the highest of three readings made at
           one-minute intervals. Single readings only will be taken at other times.

        3. Endoscopic Bronchoscopy An operator approved by the Royal Brompton Ethics Committee will
           perform all bronchoscopies. The bronchoscopist that will perform these procedures is Dr
           Borja Cosio. Subjects will attend the bronchoscopy suite at 8.30 am after having fasted
           from midnight. Subjects will have pre-treatment with atropine (0.6 mg iv) and midazolam
           (5-10 mg iv). Oxygen (3 l/min) will be administered via nasal prongs throughout the
           procedure and oxygen saturation monitored with a digital oximeter. Using local
           anaesthesia with lidocaine (4%) to the upper airways and larynx, a fibreoptic
           bronchoscope (Olympus BF10 Key-Med) will be passed through the nasal passages into the
           trachea. Bronchoalveolar lavage (BAL) will be performed from the right middle lobe using
           warmed 0.9% NaCl with 4 successive aliquots of 60 ml. This is well-tolerated in subjects
           with COPD. Patients may experience pharyngeal irritation following the procedure; there
           is a 5% chance of fever following the procedure. Subjects undergoing bronchoscopy for
           clinical reasons will also be included in this study.

        4. Venous Blood Sampling 60 ml of blood will be taken by venopuncture.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Healthy non-smoking and smoking subjects, smoking participants with COPD
      
Biospecimen description: 
      RNA was isolated and sent to GeneLogic
    
Keywords: macrophages; neutrophils; lymphocytes