AJP - Lung Cellular and Molecular Physiology, Vol 266, Issue 6 655-L663, Copyright © 1994 by American Physiological Society
Platelet-derived growth factor and its receptor in lungs from patients with asthma and chronic airflow obstruction
J. D. Aubert, S. Hayashi, J. Hards, T. R. Bai, P. D. Pare and J. C. Hogg
University of British Columbia, Pulmonary Research Laboratory, St Paul's Hospital, Vancouver, Canada.
The airway walls of patients who have asthma or chronic obstructive
pulmonary disease (COPD) are thickened by an increase in the amount of
smooth muscle and connective tissue. Platelet-derived growth factor (PDGF)
is a candidate cytokine for this increase because it can produce smooth
muscle proliferation in vitro. The present study was designed to examine
the expression of PDGF and its receptor (PDGFR) in lungs from six
asthmatics, six patients with COPD, and six patients with normal lung
function. PDGF was immunolocalized to tissue macrophages, but the number of
PDGF-positive cells was similar in all three groups. PDGFR-beta was rarely
expressed on interstitial cells, and, occasionally, on bronchial
epithelium. Northern blotting, performed on tissue from the same groups,
showed a positive correlation of PDGF(B) with PDGFR-beta mRNA level (r =
0.74, P < 0.001) and a higher abundance of PDGF(B) and PDGFR-beta mRNA
in the asthmatics vs. the COPD (P < 0.05). We conclude that PDGF and its
receptor are expressed in human lungs but do not correlate closely with the
structural changes in diseased airways.
