Structure-function relationship in COPD revisited: an in vivo microscopy view.
BACKGROUND
Fibred confocal fluorescence microscopy (FCFM) is a novel technology that allows the in vivo assessment and quantification during bronchoscopy of the bronchial wall elastic fibre pattern, alveolar and vessel diameters and thickness of the elastic fibre in the alveolar wall.


OBJECTIVE
To relate these structural characteristics with lung function parameters in healthy subjects, smokers with normal spirometry and patients with chronic obstructive pulmonary disease (COPD).


METHODS
We performed FCFM in 20 never smokers, 20 smokers with normal spirometry and 23 patients with COPD who required bronchoscopy for clinical reasons. The bronchial wall elastic fibre pattern was classified as lamellar, loose and mixed pattern, and later confirmed pathologically. Airspace dimensions and extra-alveolar vessel diameters were measured. Lung function measurements and pulmonary CT scans were obtained in all participants.


RESULTS
Patients with COPD were characterised by a significantly higher prevalence of loose fibre bronchial deposition pattern and larger alveolar diameter which correlated inversely with several lung function parameters (forced expiratory volume in 1 s (FEV1) , FEV1/forced vital capacity ratio, maximum expiratory flow, carbon monoxide transfer factor and carbon monoxide transfer coefficient; p<0.05). Increased alveolar macrophages were demonstrated in active smokers with or without COPD.


CONCLUSIONS
This is the first FCFM study to describe in vivo microscopic changes in the airways and alveoli of patients with COPD that are related to lung function impairment. These findings open the possibility of assessing the in vivo effects of therapeutic interventions for COPD in future studies.
Department of Respiratory Medicine, Hospital Universitario Son Espases and Instituto de Investigación Sanitaria de Palma (IdISPa), Palma de Mallorca, Spain Ciber de Enfermedades Respiratorias (Ciberes), Bunyola, Spain.
Borja G
BG
Cosío
Department of Respiratory Medicine, Hospital Universitario Son Espases and Instituto de Investigación Sanitaria de Palma (IdISPa), Palma de Mallorca, Spain Faculty of Medicine, Chest Diseases Department, Alexandria University, Alexandria, Egypt.
Hanaa
H
Shafiek
Department of Respiratory Medicine, Hospital Universitario Son Espases and Instituto de Investigación Sanitaria de Palma (IdISPa), Palma de Mallorca, Spain.
Federico
F
Fiorentino
Department of Pathology, Hospital Universitario Son Espases, Palma de Mallorca, Spain.
Cristina
C
Gómez
Department of Respiratory Medicine, Hospital Universitario Son Espases and Instituto de Investigación Sanitaria de Palma (IdISPa), Palma de Mallorca, Spain.
Meritxell
M
López
Department of Respiratory Medicine, Hospital Universitario Son Espases and Instituto de Investigación Sanitaria de Palma (IdISPa), Palma de Mallorca, Spain.
Angel
A
Rios
Department of Respiratory Medicine, Hospital Universitario Son Espases and Instituto de Investigación Sanitaria de Palma (IdISPa), Palma de Mallorca, Spain.
Ana
A
Kersul
Department of Respiratory Medicine, Hospital Universitario Son Espases and Instituto de Investigación Sanitaria de Palma (IdISPa), Palma de Mallorca, Spain.
Bernardo
B
Togores
Department of Radiology, Hospital Universitario Son Espases, Palma de Mallorca, Spain.
Joan
J
Palmer
Department of Respiratory Medicine, Hospital Universitario Son Espases and Instituto de Investigación Sanitaria de Palma (IdISPa), Palma de Mallorca, Spain Ciber de Enfermedades Respiratorias (Ciberes), Bunyola, Spain.
Jaume
J
Sauleda
Ciber de Enfermedades Respiratorias (Ciberes), Bunyola, Spain Thorax Institute, Hospital Clinic, IDIBAPS, Univ Barcelona and FISIB, Barcelona, Spain.
Alvar
A
Agustí
D001999:Bronchoscopy; D005260:Female; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods*; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011857:Radiographic Image Interpretation, Computer-Assisted; D012129:Respiratory Function Tests; D012307:Risk Factors; D012907:Smoking / Q000503:physiopathology; D014057:Tomography, X-Ray Computed
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