Eosinophils as a potential source of platelet-derived growth factor B-chain (PDGF-B) in nasal polyposis and bronchial asthma.
Tissue remodeling in bronchial tissues from asthmatics as well as in nasal polyp (NP) tissues includes sub-basement membrane deposition of collagen, stromal deposition of extracellular matrix protein, and hypertrophy/hyperplasia of airway smooth muscle cells, which are relevant to the cellular and molecular events induced by platelet-derived growth factor (PDGF). Therefore, we investigated the localization of mRNA and protein of PDGF-B chain (PDGF-B) in NP tissues and bronchial tissues from mild and severe asthmatics by in situ hybridization and immunohistochemistry, respectively. Cells expressing PDGF-B mRNA were found in all nine NP tissues and in bronchial tissues from 2 of 6 normal subjects, 2 of 5 mild asthmatics, and all of 6 severe asthmatics examined. The vast majority of cells expressing PDGF-B mRNA were eosinophils in NP (99.7 +/- 0.2%, mean +/- SD) and asthmatic bronchial tissues (75.0 and 77.8% in mild asthma, and 92.7 +/- 8.1% in severe asthma), but no cells expressing PDGF-B mRNA were eosinophils in normal bronchial tissues. The number of cells expressing the gene in severe asthma tissues (122.3 +/- 32.2/mm2) was similar to that in NP tissues (152.8 +/- 73.9/mm2) and greater than that in mild asthma tissues (4.7 +/- 7.6/mm2, P < 0.01), which was not significantly greater than that in normal bronchial tissues (3.4 +/- 5.2/mm2). Furthermore, we detected immunolocalization of PDGF-B in NP tissues and in asthmatic bronchial tissues. The eosinophils purified from peripheral blood were demonstrated to express PDGF-B gene transcript and immunoreactivity after stimulation with A23187.(ABSTRACT TRUNCATED AT 250 WORDS)
Ohno
I
I
First Department of Internal Medicine, Tohoku University School of Medicine, Sendai, Japan.
Nitta
Y
Y
Yamauchi
K
K
Hoshi
H
H
Honma
M
M
Woolley
K
K
O'Byrne
P
P
Dolovich
J
J
Jordana
M
M
Tamura
G
G
D000328:Adult; D000368:Aged; D001249:Asthma / Q000276:immunology / Q000378:metabolism*; D001980:Bronchi / Q000737:chemistry; D004804:Eosinophils / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D008875:Middle Aged; D009298:Nasal Polyps / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis
D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger