Text Size

Airway Smooth Muscle and Asthma Severity

This study is currently recruiting participants.
Verified June 2011 by Imperial College London
Sponsor:
Collaborators:
Asthma UK
Royal Brompton & Harefield NHS Foundation Trust
Information provided by:
Imperial College London
ClinicalTrials.gov Identifier:
NCT00779870
First received: October 22, 2008
Last updated: June 22, 2011
Last verified: June 2011
History of Changes
  Purpose

Our hypothesis is that the severity of asthma is determined by the way in which airway smooth muscle cells grow and release inflammatory mediators. Our main objective is to establish how the properties of the airway smooth muscle cell varies with asthma severity. Environmental agents, such as cigarette smoke, and inflammation can give rise to oxidative stress - this is a process whereby harmful chemicals called free radicals are formed in the body and damage tissues. The damage caused can be limited/prevented by protective, or anti-oxidant mediators. We will also look at molecules involved in oxidative stress which may affect the way in which the airway smooth muscle grows and produces inflammatory mediators.


Condition Intervention
Asthma
 Other: bronchoscopy

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Cross-Sectional
Official Title: Evaluating the Role of Oxidant/Anti-oxidant Balance and the Relationship of Asthma Severity on Airway Smooth Muscle Proliferation, Migration and Cytokine Release.

Resource links provided by NLM:

MedlinePlus related topics: Antioxidants Asthma
U.S. FDA Resources

Further study details as provided by Imperial College London:

Primary Outcome Measures:
  • Difference in ASM mass between groups [ Time Frame: at time of bronchoscopy ] [ Designated as safety issue: No ]
  • Difference in ASM proliferation, migration and cytokine release between groups [ Time Frame: at time of bronchoscopy ] [ Designated as safety issue: No ]
  • Difference in intracellular oxidative stress mechanisms from ASM between groups [ Time Frame: at time of bronchoscopy ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Correlation between ASM mass and airway hyper-responsiveness (PC20) [ Time Frame: at the time of bronchoscopy ] [ Designated as safety issue: No ]

Biospecimen Retention:   Samples With DNA

endobronchial biopsies and cultured airway smooth muscle cells


Estimated Enrollment: 68
Study Start Date: October 2008
Estimated Study Completion Date: September 2012
Estimated Primary Completion Date: September 2012 (Final data collection date for primary outcome measure)
Groups/Cohorts Assigned Interventions
1
health volunteers
 Other: bronchoscopy
bronchoscopy under local anaesthetic and sedation to obtain endobronchial biopsies
2
mild asthmatics
 Other: bronchoscopy
bronchoscopy under local anaesthetic and sedation to obtain endobronchial biopsies
3
moderately-severe asthmatics
 Other: bronchoscopy
bronchoscopy under local anaesthetic and sedation to obtain endobronchial biopsies
4
severe asthmatics
 Other: bronchoscopy
bronchoscopy under local anaesthetic and sedation to obtain endobronchial biopsies

Detailed Description:

Aims and Objectives The objective of this study is to examine whether the severity of asthma is related to (and possibly caused by) ASM dysfunction. Severe asthmatics have been shown to have more ASM in bronchial biopsies than non-severe asthmatics16. Because ASM cells can be obtained from bronchial biopsies obtained via bronchoscopy, we will examine endobronchial biopsies from mild, moderate and severe asthmatics, and healthy non-asthmatic subjects to compare features of remodelling (severe asthmatic subjects will have been assessed through the Difficult Asthma Protocol at the Royal Brompton Hospital24). In particular, we will focus on ASM mass, proliferation and changes in expression of different contractile proteins (α-actin and myosin) and chemokines, and will assess in vitro the response of ASM cells to stimulation by TGF-β and IL-1β. We will also examine the effect of dexamethasone on chemokine release and induced proliferation in vitro. We will also study enzymes and anti-oxidants involved in oxidative stress, such as Nox4, MnSOD and catalase, to look at their role in regulating ASM cell proliferation and chemokine synthesis. We want to see if there is an oxidant-anti oxidant balance in ASM in severe asthma compared to non-severe asthma.

AIM:

1. To establish the difference in ASM phenotype in asthma patients of differing severity of disease in terms of ASM mass, proliferation, migration and chemokine release.

Study design There will be 3 study visits. In the first two visits, the subjects will undergo spirometry with reversibility testing, a methacholine challenge test (to assess degree of bronchial hyper-responsiveness), skin prick tests and IgE levels (to assess atopic status), measurement of exhaled nitric oxide (as a non-invasive marker of inflammation), and the asthmatic subjects will complete an Asthma Control Questionnaire and an Asthma Quality of Life Questionnaire. The third visit will be on the day admission for the bronchoscopy.

Study protocol:

Visit 1 - screening visit

  • Explain purpose of study- address any queries/concerns
  • History and examination
  • Skin prick tests
  • Blood test for full blood count, clotting profile and IgE
  • Measurement of exhaled nitric oxide (eNO)
  • Spirometry pre and post β agonist
  • Completion of Asthma Control Questionnaire and
  • Completion of Asthma Quality of Life Questionnaire

Visit 2 - Methacholine challenge test

Visit 3 - Day admission for fibreoptic bronchoscopy

  Eligibility

Ages Eligible for Study:   18 Years to 60 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population

Mild, moderate and severe asthmatics, with a control group of healthy non-smoking volunteers

Criteria

Inclusion criteria - Asthma Age 18-60 Physician diagnosis of asthma Intermittent/mild, moderate and severe asthma as per GINA guidelines [1]

For the severe asthma subjects, they will also have the following:

Major characteristics (at least one of the following criteria)

  • Treatment with continuous or near continuous (>50% of year) oral corticosteroids

  • Requirement for treatment with high dose inhaled corticosteroids (ICS) Minor characteristics (at least 2 out of the following)

    1. Requirement for daily treatment with a controller medication in addition to ICS e.g. LABA, theophylline, leukotriene antagonist
    2. Asthma symptoms requiring SABA on a daily or near daily basis
    3. Persistent airways obstruction (FEV1 <80% predicted, diurnal PEF variation >20%)
    4. One or more emergency care visits for asthma per year
    5. 3 or more steroid "bursts" per year
    6. Prompt deterioration with ≤ 25% reduction in oral or ICS

    7. Near fatal asthma event in the past

      Reference [1] GINA - The Global Initiative for Asthma. www.ginasthma.com

      Exclusion criteria - Asthma Intubation for asthma within 6 months of entry into this study Current smokers, or less than 3 years since quitting smoking (< 5 pack/years) Less than 4 weeks from an exacerbation On steroid-sparing agent or immunosuppressant such as azathioprine, methotrexate and ciclosporin Concomitant anti-IgE therapy On anti-platelet or anti-coagulant drugs Low platelet count Pregnancy or breast-feeding Previous bronchoscopy within three months of this study

      Healthy volunteer subjects:

      We are aiming for 5 atopic and 5 non-atopic healthy volunteers.

      Inclusion criteria:

      Age 18 - 60 Non smokers (or less than 5 pack/yrs if ex-smokers) Normal lung function

      Exclusion criteria:

      History of asthma or allergic rhinitis Any chronic illness Current smokers, or less than 3 years since quitting smoking (< 5 pack/years) PC20 less than 16mg/ml On anti-platelet or anti-coagulant drugs Low platelet count Pregnancy or breast-feeding Previous bronchoscopy within three months of this study

  Contacts and Locations
Please refer to this study by its ClinicalTrials.gov identifier: NCT00779870

Contacts
Contact: Patricia Macedo, MBBS MRCP Msc 00442073518051 p.macedo@imperial.ac.uk
Contact: Florence Chow, RGN 00442073518051 florence.chow@imperial.ac.uk

Locations
United Kingdom
Royal Brompton Hospital Recruiting
London, United Kingdom, Sw3 6NP
Contact: Florence Chow, RGN     00442073518051     florence.chow@imperial.ac.uk    
Sponsors and Collaborators
Imperial College London
Asthma UK
Royal Brompton & Harefield NHS Foundation Trust
Investigators
Principal Investigator: Kian F Chung, MBBS MD FRCP DSc Imperial College London
  More Information

No publications provided

Responsible Party: Professor Kian Fan Chung, Imperial College London
ClinicalTrials.gov Identifier: NCT00779870     History of Changes
Other Study ID Numbers: 08/H0708/2
Study First Received: October 22, 2008
Last Updated: June 22, 2011
Health Authority: United Kingdom: National Health Service
United Kingdom: Research Ethics Committee

Keywords provided by Imperial College London:
asthma severity
airway smooth muscle
oxidative stress

Additional relevant MeSH terms:
Asthma
Bronchial Diseases
Respiratory Tract Diseases
Lung Diseases, Obstructive
Lung Diseases
 Respiratory Hypersensitivity
Hypersensitivity, Immediate
Hypersensitivity
Immune System Diseases

ClinicalTrials.gov processed this record on May 22, 2013