Alterations in myocardial tissue factor expression and cellular localization in dilated cardiomyopathy.
OBJECTIVE
We investigated the myocardial localization and expression of tissue factor (TF) and alternatively spliced human tissue factor (asHTF) in patients with dilated cardiomyopathy (DCM).


BACKGROUND
Tissue factor is expressed in cardiac muscle and may play a role in maintaining myocardial structure.


METHODS
Myocardial biopsies were obtained from patients with a normal or mildly impaired ejection fraction (EF) (> or =50%) and moderate to severely reduced EF (<50%). Explanted DCM hearts were also examined. Myocardial TF expression level was assessed by real-time polymerase chain reaction, TF protein by enzyme-linked immunosorbent assay, and localization by immunohistochemistry.


RESULTS
We report the identification of asHTF in the human myocardium: it was located in cardiomyocytes and endothelial cells. Quantification of myocardial TF messenger ribonucleic acid in DCM revealed a decrease in the TF/glyceraldehyde-3-phosphate dehydrogenase (GAPDH) ratio (1.76 x 10(-1) +/- 6.08 x 10(-2) for EF > or =50% [n = 19] vs. 1.06 x 10(-1) +/- 5.26 x 10(-2) for EF <50% [n = 27]; p < 0.001) and asHTF/GAPDH ratio (13.91 x 10(-5) +/- 11.20 x 10(-5) for EF > or =50% vs. 7.17 x 10(-5) +/- 3.82 x 10(-5) for EF <50%; p = 0.014). Tissue factor isoform expression level was also decreased in explanted DCM hearts (p < 0.01; n = 12). Total TF protein was reduced by 26% in DCM (p < 0.05). The TF/GAPDH ratio correlated positively with the EF (r = 0.504, p < 0.0001). Immunohistochemistry showed TF localized to the sarcolemma and Z-bands of the cardiomyocytes in patients with normal EF, whereas TF was found in the cardiomyocytic cytosol around the nucleus in DCM.


CONCLUSIONS
Tissue factor was down-regulated in the myocardium of DCM patients. The reduction in TF expression and change in localization may influence cell-to-cell contact stability and contractility, thereby contributing to cardiac dysfunction in DCM.
Szotowski
Björn
B
Department of Cardiology and Pneumology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Hindenburgdamm 30, 12200 Berlin, Germany.
Goldin-Lang
Petra
P
Antoniak
Silvio
S
Bogdanov
Vladimir Y
VY
Pathirana
Delano
D
Pauschinger
Matthias
M
Dörner
Andrea
A
Kuehl
Uwe
U
Coupland
Sarah
S
Nemerson
Yale
Y
Hummel
Michael
M
Poller
Wolfgang
W
Hetzer
Roland
R
Schultheiss
Heinz-Peter
HP
Rauch
Ursula
U
D015153:Blotting, Western; D002311:Cardiomyopathy, Dilated / Q000378:metabolism* / Q000473:pathology; D016022:Case-Control Studies; D017931:DNA Primers; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012720:Severity of Illness Index; D013925:Thromboplastin / Q000235:genetics / Q000378:metabolism*
D017931:DNA Primers; D012333:RNA, Messenger; D013925:Thromboplastin