Clinical Features and Airways Inflammation in Never Smokers and Smokers With COPD

September 6, 2017 updated by: Myriam Denguezli, Ministry of Scientific Research, Tunisia

Airway Inflammatory Profile and Clinical Presentation of COPD: A Comparison Between Never Smokers and Smokers

The aim of this study was to investigate the airway inflammatory profile and the clinical presentation of chronic obstructive pulmonary disease (COPD) in never smokers compared to smokers with COPD.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

40 COPD patients (21 smokers and 19 never smokers) and 28 healthy never smokers were included in the present study. Information about respiratory symptoms and comorbidities were collected. Subjects underwent pulmonary function tests and COPD was defined according to Global Initiative for Chronic Obstructive lung Disease spirometric criteria. Induced sputum was collected to determine total and differential inflammatory cells counts as well as inflammatory mediators (Interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-α)). The Mann-Whitney U and the χ2 tests were used for results comparisons. Correlations between symptoms, spirometric parameters, cytokines levels, inflammatory cells and risk factors of COPD were examined with Spearman's rank correlation test.

Study Type

Observational

Enrollment (Actual)

68

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

40 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Patients were recruited from the department of physiology and functional explorations of Sousse University Hospital. 40 subjects with COPD, according to GOLD criteria (21 current smokers and 19 never smokers) and 28 healthy control subjects participated to the study.

Description

Inclusion Criteria:

  • Subjects with COPD, according to GOLD criteria (smokers and never smokers). Moreover, inhaled short-acting β2-agonists were stopped at least 8h before the test and inhaled long-acting β2-agonist were stopped at least 48h before the test.
  • Healthy control subjects : never smokers with normal spirometry and did not have a history of lung disease or chronic respiratory symptoms.

Exclusion Criteria:

  • COPD patients were excluded from the study if they had an exacerbation, a respiratory tract infection or if they used a systemic form of corticosteroid preparation (oral or intravenous injection therapy) or antibiotics within the two months prior to the study entry. Patients with other respiratory disorder like pneumonia, pulmonary emboli, congestive heart failure, lung cancer or tuberculosis were also excluded.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Case-Control
  • Time Perspectives: Retrospective

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Healthy subjects

Healthy non-smoking subjects were never smokers with normal spirometry and did not have a history of lung disease or chronic respiratory symptoms.

Information about respiratory symptoms and comorbidities were collected. Healthy subjects underwent pulmonary function tests (Spirometry). Induced sputum was collected to determine total and differential inflammatory cells counts as well as inflammatory mediators (Interleukin-8 and tumor necrosis factor-alpha).

Induced sputum was collected and analysed in the three arms (Healthy subjects, Never smokers with COPD and smokers with COPD) The volume of the sputum sample, was treated with an equal volume of 0.1% dithiothreitol. The samples were then vortexed and placed in a shaking water bath at 37°C for 15 min to ensure complete homogeneisation. The suspensions were centrifuged at 400× g and the sputum supernatant stored at -80°C until cytokines analysis. The cell pellet was resuspended in 0.5% bovine serum albumin in phosphate buffered saline and cytospin were made by putting 100 µL of the cell suspension in the funnels.

Slides for differential cell counts were stained with May-Grünwald Giemsa.

All the subjects underwent pulmonary function tests (Healthy subjects, Never smokers with COPD and smokers with COPD).

Pulmonary function parameters were measured using a portable spirometer (Easy One ndd. Medizintechnik; Zurich, Switzerland) according to the ATS criteria (American Thoracic Society). Reversibility test was performed 15 min after inhalation of 400 µg of Salbutamol (Ventolin, GlaxoSmithKline, Middlesex, UK). All spirometry data were graded for quality and only tests that met high quality scores were used for the final analysis.

Other Names:
  • spirometry

IL-8 and TNF-α were measured in the sputum supernatant of all the subjects (Healthy subjects, Never smokers with COPD and smokers with COPD).

Commercially available kits were used to detect IL-8 (Human IL-8 Immuno-Biological Laboratories ELISA Kit) and TNF-α (Human TNF-alpha Sigma-Aldrich ELISA Kit) concentrations in the sputum supernatants. The absorbance was measured at 450 nm. The lower limits detection were 2 pg/mL for IL-8 and 5 pg/mL for TNF-α. The intra assay coefficients of variability were 8.7% for IL-8 and 7.7% for TNF- α.

Other Names:
  • ELISA
COPD Never smokers

Never smokers referred to subjects who had never smoked Airflow limitation in COPD was defined as a post-bronchodilator forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC) ratio <70% and FEV1 reversibility of <12% and 200 mL from baseline values after inhalation of 400 µg of Salbutamol.

Information about respiratory symptoms and comorbidities were collected. Never smoking subjects with COPD underwent pulmonary function tests (Spirometry). Induced sputum was collected to determine total and differential inflammatory cells counts as well as inflammatory mediators (Interleukin-8 and tumor necrosis factor-alpha).

Induced sputum was collected and analysed in the three arms (Healthy subjects, Never smokers with COPD and smokers with COPD) The volume of the sputum sample, was treated with an equal volume of 0.1% dithiothreitol. The samples were then vortexed and placed in a shaking water bath at 37°C for 15 min to ensure complete homogeneisation. The suspensions were centrifuged at 400× g and the sputum supernatant stored at -80°C until cytokines analysis. The cell pellet was resuspended in 0.5% bovine serum albumin in phosphate buffered saline and cytospin were made by putting 100 µL of the cell suspension in the funnels.

Slides for differential cell counts were stained with May-Grünwald Giemsa.

All the subjects underwent pulmonary function tests (Healthy subjects, Never smokers with COPD and smokers with COPD).

Pulmonary function parameters were measured using a portable spirometer (Easy One ndd. Medizintechnik; Zurich, Switzerland) according to the ATS criteria (American Thoracic Society). Reversibility test was performed 15 min after inhalation of 400 µg of Salbutamol (Ventolin, GlaxoSmithKline, Middlesex, UK). All spirometry data were graded for quality and only tests that met high quality scores were used for the final analysis.

Other Names:
  • spirometry

IL-8 and TNF-α were measured in the sputum supernatant of all the subjects (Healthy subjects, Never smokers with COPD and smokers with COPD).

Commercially available kits were used to detect IL-8 (Human IL-8 Immuno-Biological Laboratories ELISA Kit) and TNF-α (Human TNF-alpha Sigma-Aldrich ELISA Kit) concentrations in the sputum supernatants. The absorbance was measured at 450 nm. The lower limits detection were 2 pg/mL for IL-8 and 5 pg/mL for TNF-α. The intra assay coefficients of variability were 8.7% for IL-8 and 7.7% for TNF- α.

Other Names:
  • ELISA
COPD Smokers

Smokers were defined as persons who had smoked > 20 packs of cigarettes in a lifetime and who continue smoking every day.

Airflow limitation in COPD was defined as a post-bronchodilator forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC) ratio <70% and FEV1 reversibility of <12% and 200 mL from baseline values after inhalation of 400 µg of Salbutamol.

Information about respiratory symptoms and comorbidities were collected. Smoking subjects with COPD underwent pulmonary function tests (Spirometry). Induced sputum was collected to determine total and differential inflammatory cells counts as well as inflammatory mediators (Interleukin-8 and tumor necrosis factor-alpha).

Induced sputum was collected and analysed in the three arms (Healthy subjects, Never smokers with COPD and smokers with COPD) The volume of the sputum sample, was treated with an equal volume of 0.1% dithiothreitol. The samples were then vortexed and placed in a shaking water bath at 37°C for 15 min to ensure complete homogeneisation. The suspensions were centrifuged at 400× g and the sputum supernatant stored at -80°C until cytokines analysis. The cell pellet was resuspended in 0.5% bovine serum albumin in phosphate buffered saline and cytospin were made by putting 100 µL of the cell suspension in the funnels.

Slides for differential cell counts were stained with May-Grünwald Giemsa.

All the subjects underwent pulmonary function tests (Healthy subjects, Never smokers with COPD and smokers with COPD).

Pulmonary function parameters were measured using a portable spirometer (Easy One ndd. Medizintechnik; Zurich, Switzerland) according to the ATS criteria (American Thoracic Society). Reversibility test was performed 15 min after inhalation of 400 µg of Salbutamol (Ventolin, GlaxoSmithKline, Middlesex, UK). All spirometry data were graded for quality and only tests that met high quality scores were used for the final analysis.

Other Names:
  • spirometry

IL-8 and TNF-α were measured in the sputum supernatant of all the subjects (Healthy subjects, Never smokers with COPD and smokers with COPD).

Commercially available kits were used to detect IL-8 (Human IL-8 Immuno-Biological Laboratories ELISA Kit) and TNF-α (Human TNF-alpha Sigma-Aldrich ELISA Kit) concentrations in the sputum supernatants. The absorbance was measured at 450 nm. The lower limits detection were 2 pg/mL for IL-8 and 5 pg/mL for TNF-α. The intra assay coefficients of variability were 8.7% for IL-8 and 7.7% for TNF- α.

Other Names:
  • ELISA

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Weight measurement
Time Frame: 6 months
Weight was measured in kilograms for all the participants.
6 months
Height measurement
Time Frame: 6 months
Height was measured in meters for all the participants.
6 months
Forced vital capacity (FVC)
Time Frame: 6 months
FVC was measured using a portable spirometer (Easy One ndd. Medizintechnik; Zurich, Switzerland) according to the American Thoracic Society criteria.
6 months
Forced expiratory volume in one second (FEV1)
Time Frame: 6 months
FEV1 was measured using a portable spirometer (Easy One ndd. Medizintechnik; Zurich, Switzerland) according to the American Thoracic Society criteria.
6 months
Sputum induction and collection
Time Frame: 6 months
Sputum induction was conducted by inhalation of nebulised sterile hypertonic saline solution followed by coughing and expectoration of airway secretions. For nebulisation, an ultrasound nebulizer was used for 5-20 min to provide an adequate amount of sample. The subject is asked to cough and expectorate at 5 min intervals.
6 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
BMI determination
Time Frame: 6 months
Weight and height values were combined to report BMI in kg/m2
6 months
Tiffeneau ratio (FEV1/FVC)
Time Frame: 6 months
The calculation of FEV1/FVC allows the identification of obstructive ventilatory defect. A FEV1/FVC < 70 % where FEV1 is reduced more than FVC signifies an obstructive defect.
6 months
Sputum cell counts
Time Frame: 1 month
Four hundred non-squamous cells were counted by two technicians and the mean of the two scores was expressed as percentage of the total cell count. Sputum samples containing >20% of squamous cells and/or with cell viability <70% were excluded from analysis.
1 month
Sputum supernatant analyses
Time Frame: 3 months
IL-8 and TNF-α sputum supernatant concentrations were measured in the sputum supernatant of the three studied groups using ELISA test.
3 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Investigators

  • Study Director: Zouhair Tabka, MD PhD, Faculty of Medicine of Sousse
  • Principal Investigator: Amina Mrizak, MSc, Faculty of Medicine of Sousse

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 1, 2013

Primary Completion (Actual)

August 1, 2016

Study Completion (Actual)

January 1, 2017

Study Registration Dates

First Submitted

August 24, 2017

First Submitted That Met QC Criteria

September 6, 2017

First Posted (Actual)

September 7, 2017

Study Record Updates

Last Update Posted (Actual)

September 7, 2017

Last Update Submitted That Met QC Criteria

September 6, 2017

Last Verified

September 1, 2017

More Information

Terms related to this study

Other Study ID Numbers

  • COPDNS

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

Yes

IPD Plan Description

All IPD that underlie results will be shared in a publication

IPD Sharing Time Frame

The data will become available when the article will be accepted by the editorial board of the journal.

IPD Sharing Supporting Information Type

  • Study Protocol
  • Clinical Study Report (CSR)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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