Expression of HSP47 in usual interstitial pneumonia and nonspecific interstitial pneumonia.
BACKGROUND
Heat shock protein (HSP) 47, a collagen-specific molecular chaperone, is involved in the processing and/or secretion of procollagens, and its expression is increased in various fibrotic diseases. The aim of this study was to determine whether quantitative immunohistochemical evaluation of the expression levels of HSP47, type I procollagen and alpha-smooth muscle actin (SMA) allows the differentiation of idiopathic usual interstitial pneumonia (UIP) from UIP associated with collagen vascular disease (CVD) and idiopathic nonspecific interstitial pneumonia (NSIP).


METHODS
We reviewed surgical lung biopsy specimens of 19 patients with idiopathic UIP, 7 with CVD-associated UIP and 16 with idiopathic NSIP and assigned a score for the expression of HSP47, type I procollagen and alpha-SMA in type II pneumocytes and/or lung fibroblasts (score 0 = no; 1 = weak; 2 = moderate; 3 = strong staining).


RESULTS
The expression level of HSP47 in type II pneumocytes of idiopathic UIP was significantly higher than in CVD-associated UIP and idiopathic NSIP. The expression of HSP47 in fibroblasts was significantly higher in idiopathic UIP and idiopathic NSIP than in CVD-associated UIP. The expression of type I procollagen in type II pneumocytes was significantly higher in idiopathic UIP than in idiopathic NSIP. The expression of type I procollagen in fibroblasts was not different in the three groups, while the expression of alpha-SMA in fibroblasts was significantly higher in idiopathic UIP than in idiopathic NSIP.


CONCLUSIONS
Our results suggest the existence of different fibrotic pathways among these groups involved in the expression of HSP47 and type I procollagen.
Kakugawa
Tomoyuki
T
Second Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan. kakugawa@jasmine.ocn.ne.jp
Mukae
Hiroshi
H
Hayashi
Tomayoshi
T
Ishii
Hiroshi
H
Nakayama
Seiko
S
Sakamoto
Noriho
N
Yoshioka
Sumako
S
Sugiyama
Kanako
K
Mine
Mariko
M
Mizuta
Yohei
Y
Kohno
Shigeru
S
D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005347:Fibroblasts / Q000378:metabolism*; D020869:Gene Expression Profiling; D050958:HSP47 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D008168:Lung / Q000378:metabolism*; D017563:Lung Diseases, Interstitial / Q000145:classification* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D014018:Tissue Distribution
D050958:HSP47 Heat-Shock Proteins