Biomedical Engineering Reference
In-Depth Information
Figure 7
Airway submucosal gland hypertrophy in COPD. The percentage of the
airway wall occupied by the glands is significantly greater in the airways of patients
who die with a diagnosis of chronic bronchitis compared with those with emphysema
or controls without respiratory disease. Redrawn after 22.
tion, mentioned above (27), in gland serous cells, a rich source of antimicro-
bial enzymes such as lysozyme and lactoferrin (37), contributes to the bac-
terial colonization of the airways that is a clinical feature of many COPD
patients (3).
In contrast to normal airways, goblet cells in COPD contain not only
MUC5AC but also MUC5B (34,38) and MUC2 (9). This distribution is dif-
ferent to that in patients with asthma or cystic fibrosis (CF), where
MUC5AC and MUC5B show a similar histological distribution to normal
controls (39,40). Although not found consistently (23,33), there is a growing
impression that MUC2 is increased in 'irritated' airways, including COPD
(9,36,41).
IV. ABNORMALITIES IN MUCOCILIARY CLEARANCE
IN COPD
Aberrant airway mucus in COPD goes in concert with aberrant ciliated cells
and cilia. The number of ciliated cells and ciliary length of cilia is decreased
in patients with chronic bronchitis (42). Ciliary abnormalities include
compound cilia, cilia enclosed within periciliary sheaths, cilia with abnormal
