A profibrotic effect of plasminogen activator inhibitor type-1 (PAI-1) in the heart.
Increased expression of PAI-1 is profibrotic in several organs. However, its potentially profibrotic effects in the heart subjected to infarction have not been elucidated. Accordingly, we induced coronary occlusion in 10-week-old mice congenic on a C57BL6 background and in mice overexpressing PAI-1 (PTG) in multiple tissues. Compared with C57BL6 control mice without myocardial infarction (MI), PTG mice exhibited consistently elevated PAI-1 in plasma at 16 weeks of age but virtually identical PAI-1 content in left ventricular (LV) myocardium. However, they exhibited a 2-fold increase in LV PAI-1 content 6 weeks after induction of MI (4.21 +/- 1.0 ng/ml tissue protein) compared with that in C57BL6 mice (2.04 +/- 0.5, P < 0.05). In 16-week-old mice, ultrasonically delineated LV fractional shortening (FS) was comparable in normal PTG and normal C57BL6 controls. However, 6 weeks after MI, PTG (n = 21) compared with C57BL6 (n = 14) mice exhibited markedly thinner LV posterior walls in both diastole (C57BL6 0.79 +/- 0.05 mm, PTG 0.55 +/- 0.06, P < 0.05) and systole (0.97 +/- 0.05 mm, 0.75 +/- 0.06, P < 0.05); increased end systolic LV dimensions (4.54 +/- 0.2 mm, 5.17 +/- 0.2, P < 0.05); and significantly depressed FS, more impaired LV segmental function, and greater mitral E wave amplitude. Compared with fibrosis assessed by Masson staining of sections from apex to base in C57BL6 mice (10.85 +/- 0.43% LV area), PTG mice exhibited 33% more LV fibrosis after MI (P < 0.05). Thus, PAI-1 is profibrotic in the heart subjected to infarction. Accordingly, overexpression of PAI-1 is a promising target for attenuation of heart failure after MI that may be exacerbated by fibrosis.
Zaman
A K M Tarikuz
AK
University of Vermont, Colchester Research Facility, 208 South Park Drive, Colchester, VT 05446, USA.
French
Christopher J
CJ
Schneider
David J
DJ
Sobel
Burton E
BE
D000818:Animals; D001794:Blood Pressure; D001835:Body Weight; D003402:Creatine Kinase / Q000378:metabolism; D015150:Echocardiography, Doppler; D005070:Evans Blue; D005355:Fibrosis / Q000473:pathology / Q000503:physiopathology; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000201:enzymology / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology*; D009929:Organ Size; D017395:Plasminogen Activator Inhibitor 1 / Q000097:blood / Q000378:metabolism*; D016277:Ventricular Function, Left
D017395:Plasminogen Activator Inhibitor 1; D005070:Evans Blue; D003402:Creatine Kinase