Macrophage Phagocytosis in COPD

Macrophage Phagocytosis in Chronic Obstructive Pulmonary Disease

Patients with chronic obstructive pulmonary disease (COPD) that have frequent chest infections are the patients most likely to become worse over time. Why these people are more susceptible to chest infections is not known. One reason might be that the white cells in their lungs called macrophages do not work properly. Normally, these cells remove all the debris inhaled into the lung. This can also include bacteria. In patients with COPD, these macrophages are not able to remove these particles. The research question addresses why this happens

Study Overview

• Status: Completed
• Conditions: Chronic Obstructive Pulmonary Disease; Emphysema; Chronic Bronchitis

Detailed Description

Chronic obstructive pulmonary disease (COPD) comprises chronic bronchitis, small airways disease and emphysema. The major risk factor for the development of COPD is cigarette smoking therefore, the prevalence of this disease is increasing. COPD accounts for increasing numbers of hospital admissions due to increased numbers of chest infections and exacerbations. This may be related to the reduced capacity of macrophages from COPD patients to phagocytose bacteria and apoptotic cells. The reasons for this defect in the innate immune response in these subjects is unclear but there are suggestions that scavenger receptors may be altered by oxidative stress and reduce the phagocytotic pathway. This would be relevant in COPD, as increased oxidative stress is associated with cigarette smoking. We have preliminary data that shows a similar reduce phagocytotic response in monocyte-derived macrophages (MDM) from COPD patients compared with smokers and non-smokers. As these cells have not been exposed to oxidative stress other mechanisms may play a role in reducing phagocytosis. Using this MDM model, by taking blood from patients with COPD, we aim to investigate the mechanism of defective phagocytosis in COPD. We will measure the expression and regulation of cell surface scavenger receptors in cells of disease patients and control subjects and examine the signalling pathways leading to actin polymerization and phagosome formation. Finally, we aim to identify novel therapeutic strategies to reverse this effect and augment phagocytosis of macrophages in patients with COPD. Such a strategy would reduce chest infections and exacerbations and hence improve quality of life.

• Study Type: Observational
• Enrollment (Actual): 56

Contacts and Locations

Study Locations

• United Kingdom
  • London, United Kingdom, SW3 6LY
    • Imperial College London

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Healthy subjects, smokers without COPD and COPD patients

Description

Inclusion Criteria:

Healthy non-smoking subjects:

All normal volunteers will meet the following criteria:

Age 21-75 years. No history of respiratory or allergic disease. Normal baseline spirometry as predicted for age, sex and height. Non-smokers. No history of upper respiratory tract infection in the preceding six weeks. Not taking regular medication

COPD subjects:

COPD is diagnosed according to American Thoracic Society, European Respiratory Society and British Thoracic Society guidelines by the doctors in Professor Barnes' COPD clinic.

All COPD volunteers will meet the following criteria:

Age between 35-75 years. A smoking history of at least 10 pack years. ( 1 pack year = 20 cigarettes per day for 1 year) FEV1:FVC ratio of <0.7, post-bronchodilator FEV1 of <85% predicted, reversibility with inhaled beta2-agonist of <15% of predicted FEV1: all three criteria are required.

Exclusion Criteria:

Subjects will not included in this study if they meet any of the following exclusion criteria:

Clinically significant findings in the medical history or on physical examination other than those of COPD in the COPD group.

Pregnant women or mothers who are breastfeeding. Subjects who are unable to give informed consent.-

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
Non smokers; Non smokers included no history of respiratory or allergic disease, normal baseline spirometry
Smokers; Smoking history of at least 10 pack years
COPD; Patients with stable COPD

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Phagocytosis of H. Influenzae Concentration	Measurement of phagocytosis in vitro, Phagocytosis of H. influenzae concentration	1 hour
Phagocytosis of S. Pneumoniae Concentration	Measurement of phagocytosis in vitro, Phagocytosis of S. pneumoniae concentration	1 hour

Collaborators and Investigators

• Sponsor: Imperial College London
• Investigators: Principal Investigator: Louise E Donnelly, PhD, Imperial College London

Publications and helpful links

General Publications

• Taylor AE, Finney-Hayward TK, Quint JK, Thomas CM, Tudhope SJ, Wedzicha JA, Barnes PJ, Donnelly LE. Defective macrophage phagocytosis of bacteria in COPD. Eur Respir J. 2010 May;35(5):1039-47. doi: 10.1183/09031936.00036709. Epub 2009 Nov 6.

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2005
• Primary Completion (Actual): December 1, 2010
• Study Completion (Actual): December 1, 2010

Study Registration Dates

• First Submitted: March 1, 2006
• First Submitted That Met QC Criteria: March 1, 2006
• First Posted (Estimate): March 2, 2006

Study Record Updates

• Last Update Posted (Actual): December 3, 2019
• Last Update Submitted That Met QC Criteria: November 22, 2019
• Last Verified: November 1, 2019

More Information

Terms related to this study

• Keywords: exacerbation; macrophage; phagocytosis
• Additional Relevant MeSH Terms: Pathologic Processes; Infections; Respiratory Tract Infections; Respiratory Tract Diseases; Bronchial Diseases; Lung Diseases; Lung Diseases, Obstructive; Pulmonary Disease, Chronic Obstructive; Emphysema; Bronchitis; Bronchitis, Chronic
• Other Study ID Numbers: 05/Q0404/111

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No