Urokinase-type plasminogen activator plays a critical role in angiotensin II-induced abdominal aortic aneurysm.
We have previously demonstrated that urokinase-type plasminogen activator (uPA) is highly expressed in the aneurysmal segment of the abdominal aorta (AAA) in apolipoprotein E-deficient (apoE-/-) mice treated with angiotensin II (Ang II). In the present study, we tested the hypothesis that uPA is essential for AAA formation in this model. An osmotic minipump containing Ang II (1.44 mg/kg per day) was implanted subcutaneously into 7- to 11-month-old male mice for 1 month. Ang II induced AAA in 9 (90%) of 10 hyperlipidemic mice deficient in apoE (apoE-/-/uPA+/+ mice) but in only 2 (22%) of 9 mice deficient in both apoE and uPA (apoE-/-/uPA-/- mice) (P<0.05). Although the expansion of the suprarenal aorta was significantly less in apoE-/-/uPA-/- mice than in apoE-/-/uPA+/+ mice, the aortic diameters of the aorta immediately above or below the suprarenal aorta were similar between the 2 groups. Ang II induced AAA in 7 (39%) of 18 strain-matched wild-type C57 black/6J control mice. The incidence was significantly higher in atherosclerotic apoE-deficient (apoE-/-) mice, in which 8 (100%) of 8 mice developed AAA. Only 1 (4%) of 27 uPA-/- mice developed AAA after Ang II treatment. We conclude the following: (1) uPA plays an essential role in Ang II-induced AAA in mice with or without preexisting hyperlipidemia and atherosclerosis; (2) uPA deficiency does not affect the diameter of the nonaneurysmal portion of the aorta; and (3) atherosclerosis and/or hyperlipidemia promotes but is not essential for Ang II-induced AAA formation in this model.
Deng
Gary G
GG
Berlex Biosciences, Department of Pharmacology and Cardiovascular Research, PO Box 4099, 2600 Hilltop Dr, Richmond, Calif 94804-0099, USA. j
Martin-McNulty
Baby
B
Sukovich
Drew A
DA
Freay
Ana
A
Halks-Miller
Meredith
M
Thinnes
Therese
T
Loskutoff
David J
DJ
Carmeliet
Peter
P
Dole
William P
WP
Wang
Yi-Xin
YX
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000378:metabolism / Q000473:pathology; D017544:Aortic Aneurysm, Abdominal / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology; D001057:Apolipoproteins E / Q000235:genetics; D001161:Arteriosclerosis / Q000473:pathology; D017403:In Situ Hybridization; D015850:Interleukin-6 / Q000378:metabolism; D008297:Male; D020782:Matrix Metalloproteinases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D012333:RNA, Messenger / Q000378:metabolism; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics / Q000502:physiology*
D001057:Apolipoproteins E; D015850:Interleukin-6; D012333:RNA, Messenger; D000804:Angiotensin II; D014568:Urokinase-Type Plasminogen Activator; D020782:Matrix Metalloproteinases