Decreased expression of TGF-beta type II receptor in bronchial glands of smokers with COPD.
BACKGROUND
The role of transforming growth factor-beta1 (TGF-beta1) in chronic obstructive pulmonary disease is still controversial, but it has been proposed that it may protect from mucus hypersecretion since it is able to downregulate mucin production. A study was undertaken to investigate the expression of TGF-beta1 and its type II receptor (TGF-beta RII) in the bronchial glands of smokers with COPD.


METHODS
The expression of TGF-beta(1) and TGF-beta RII were examined immunohistochemically in the bronchial glands of 24 smokers undergoing lung resection for solitary peripheral nodules: 12 with airflow limitation (smokers with COPD) and 12 with normal lung function.


RESULTS
The expression of TGF-beta1 in bronchial glands was similar in the two groups of subjects while that of TGF-beta RII was lower in smokers with COPD than in smokers with normal lung function (p=0.004). TGF-beta RII expression was inversely correlated with the values of Reid's index, a measure of gland size (p=0.02, r=-0.50).


CONCLUSIONS
In the bronchial glands of smokers with COPD there is decreased expression of TGF-beta RII which is associated with bronchial gland enlargement. These findings support the view that the absence of TGF-beta signalling may induce structural changes in the bronchial glands which, in turn, may promote mucus hypersecretion.
Baraldo
S
S
Department of Cardio-Thoracic and Vascular Sciences, Section of Respiratory Diseases, University of Padova, Italy.
Bazzan
E
E
Turato
G
G
Calabrese
F
F
Beghé
B
B
Papi
A
A
Maestrelli
P
P
Fabbri
L M
LM
Zuin
R
R
Saetta
M
M
D000368:Aged; D001980:Bronchi / Q000378:metabolism*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D017346:Protein Serine-Threonine Kinases; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism*; D014797:Vital Capacity / Q000502:physiology
D018125:Receptors, Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II