Enhanced myocardial cathepsin B expression in patients with dilated cardiomyopathy.
OBJECTIVE
Cathepsin B is a prominent lysosomal protease and is involved in apoptosis as well as degradation of myofibrillar proteins in myocardial infarction. The aim of this study was to investigate myocardial cathepsin B expression in failing and non-failing human hearts.


METHODS
Tissue samples were taken from transplanted left ventricles from 20 patients with dilated cardiomyopathy and 5 non-failing donor hearts that could not be transplanted for technical reasons. Myocardial cathepsin B expression was determined by immunohistochemistry, the reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. Apoptosis was assessed by TUNEL staining.


RESULTS
Positive cathepsin B staining was found in failing and non-failing hearts. The expression of cathepsin B at mRNA and protein levels was significantly higher in failing hearts compared with non-failing hearts. Correlation analysis revealed that cathepsin B at mRNA and protein levels negatively correlated with EF (r=0.66, p=0.002 and r=0.492, p=0.028, respectively) in patients with heart failure. The apoptotic index was 0.015+/-0.006 in failing hearts and 0.002+/-0.001 in non-failing hearts (p<0.01).


CONCLUSIONS
Increased myocardial expression of cathepsin B was found in patients with heart failure suggesting that cathepsin B might play a role in the genesis and development of heart failure.
Ge
Junbo
J
Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Fenglin Road 180, Shanghai 200032, PR China. gejunbo@zshospital.net
Zhao
Gang
G
Chen
Ruizhen
R
Li
Shuangjie
S
Wang
Shijun
S
Zhang
Xingang
X
Zhuang
Yamin
Y
Du
Jiuzhong
J
Yu
Xiaohua
X
Li
Gaoping
G
Yang
Yingzhen
Y
D000293:Adolescent; D000328:Adult; D017209:Apoptosis; D002311:Cardiomyopathy, Dilated / Q000201:enzymology*; D002401:Cathepsin B / Q000032:analysis / Q000235:genetics*; D002648:Child; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000201:enzymology*
D002401:Cathepsin B