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Submitted on September 4, 2007
Accepted on February 9, 2008
in Arterial Elastocalcinosis
From the Faculty of Pharmacy (C.B., S.M., J.B., P.M.), and the Department of Pharmacology, Faculty of Medicine (D.d.B.), University of Montreal, Québec, Canada.
* To whom correspondence should be addressed. E-mail: pierre.moreau{at}umontreal.ca.
Objective—Isolated systolic hypertension is associated with increased elastase activity, vascular calcification, and vascular stiffness. We sought to determine the importance of elastase activity and matrix degradation in the development of elastocalcinosis.
Methods and Results—Elastocalcinosis was induced in vivo and ex vivo using warfarin. Hemodynamic parameters, calcium deposition, elastin degradation, transforming growth factor (TGF)-
signaling, and elastase activity were evaluated at different time points in the in vivo model. Metalloproteinases, serine proteases, and cysteine proteases were blocked to measure their relative implication in elastin degradation. Gradual elastocalcinosis was obtained, and paralleled the elastin degradation pattern. Matrix metalloproteinase (MMP)-9 activity was increased at 5 days of warfarin treatment, whereas TGF-
signaling was increased at 7 days. Calcification was significantly elevated after 21 days. Blocking metalloproteinases activation with doxycycline and TGF-
signaling with SB-431542 were able to prevent calcification.
Conclusions—Early MMP-9 activation precedes the increase of TGF-
signaling, and overt vascular elastocalcinosis and stiffness. Modulation of matrix degradation could represent a novel therapeutic avenue to prevent the gradual age-related stiffening of large arteries, leading to isolated systolic hypertension.
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