Overexpression of transforming growth factor beta1 in smooth muscle cells of human abdominal aortic aneurysm.
OBJECTIVE
to examine the expression of transforming growth factor beta1 (TGF-beta1) and the cell kinetics of smooth muscle cells (SMCs) at the neck of abdominal aortic aneurysms (AAAs).


METHODS
expression of alpha-smooth muscle actin and TGF-beta1 was evaluated by immunostaining, and cell kinetics were estimated by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) assay and Ki-67 immunostaining in 11 AAAs (at both the dilated region and the neck) and eight occlusive aortas.


RESULTS
the TUNEL-positive SMC ratio in the neck and dilated region was significantly higher than in the occlusive aorta (p<0.01). The percentage of Ki-67-positive SMCs in the neck was significantly higher than in the dilated region (p<0.01) and the occlusive aorta (p=0.032). When compared with the occlusive aorta, the aneurysmal neck had increased TGF-beta1 expression (p=0.01) and reduced SMC density, and the aneurysmal dilated aorta had much more increased TGF-beta1 expression (p<0.01) and much more reduced SMC density (p<0.01).


CONCLUSIONS
these results suggest that overexpression of TGF-beta1 might be associated with the reduction of SMC density through SMC apoptosis and reduced proliferative ability of SMCs, leading to dilatation in AAAs.
Fukui
D
D
First Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, 390-8621, Japan.
Miyagawa
S
S
Soeda
J
J
Tanaka
K
K
Urayama
H
H
Kawasaki
S
S
D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000378:metabolism / Q000473:pathology*; D001024:Aortic Valve Stenosis / Q000378:metabolism; D006801:Humans; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D012720:Severity of Illness Index; D016212:Transforming Growth Factor beta / Q000096:biosynthesis*; D053773:Transforming Growth Factor beta1
C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1