Sequential Activation of Matrix Metalloproteinase 9 and Transforming Growth Factor β in Arterial Elastocalcinosis

Abstract

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. Elastocalcinosis is characterized by a deposition of hydroxyapatite on the elastic lamellae of arteries. It occurs independently of atherosclerosis. 2 Until recently, it was considered as a passive process, taking place with time. However, several studies demonstrated that vascular calcification is an active phenomenon controlled by serum and matrix proteins, such as matrix Gla protein. 3 Moreover, it involves phenotypic changes of vascular smooth muscle cells with the expression of bone-related proteins. 4 Aging is associated with an increased collagen/elastin ratio explained in part by an enhanced degradation of elastin. 5,6 Indeed, elastase activity, mainly endopeptidases, including cysteine proteases, serine proteases, and metalloproteinases, is increased with age in human aortas. 7 In the context of aging and vascular calcification, metalloproteinases, especially matrix metalloproteinases (MMPs), have been thoroughly studied. Investigations on the genetic mutations of MMPs demonstrated its contribution to age-related large artery stiffening. 8,9 Furthermore, enhanced MMP-9 and MMP-2 levels and serum elastase activity were observed in patients with ISH and correlated independently with PWV. 10 In 2000, Vyavahare et al showed for the first time that elastin calcification was blunted by a site specific delivery of MMP inhibitor. 11 Moreover, Qin et al demonstrated, in an animal model, that matrix metalloproteinase inhibition with doxycycline and GM6001 decreased hydroxyapatite accumulation in the aorta. 12 These results suggest that MMPs and elastin degradation are involved in MEC.Elastin degradation induces the release of soluble elastin pep...

Two Sides of MGP Null Arterial Disease

“…However, our histologic analysis of the elastic lamellae in calcifying arteries of rats treated with warfarin to induce elastocalcinosis (30,31,56) did not reveal overt elastin fragmentation (data not shown) in contrast to MGP null arteries. Further, in warfarin- induced calcification, previous studies identified activation of MMP-9 and no induction of serine elastases (22), whereas in the MGP null arteries, the elevated elastase activity is derived from the serine protease adipsin. Together, these results question the role of MGP carboxylation in the regulation of elastolytic activity in VSMCs.…”

Mechanisms of Aortic and Cardiac Dysfunction in Uremic Mice With Aortic Calcification

“…However, we cannot exclude a possible contribution of severe calcification to vascular stiffness at more advanced stages (such as stage 4 or 5 CKD 22 ) because severe calcification induced by vitamin D 3 plus nicotine or by warfarin plus vitamin K 1 in rat models has been shown to be associated with increased aortic stiffness. 12,23,24 It should be noted that in these 2 animal models, the authors observed an elevation in the ratio of aortic collagen to elastin in association with the vascular calcifications, which may be the result of severe elastocalcinosis inducing destruction of elastic fibers and thus leading to arterial stiffness. 24,25 We did not observe this type of change in the ratio of aortic collagen to elastin; this could explain the absence of a correlation between vascular calcification and vascular stiffness in our present experiments.…”

“…Major medial calcifications are certainly an important factor in aortic stiffness alteration. 12 However, the development of mild to moderate calcifications such as those observed in earlier stages of CKD may not necessarily correlate with the development of aortic PWV alterations.…”

Cysteine Protease Cathepsins in Atherosclerosis-Based Vascular Disease and Its Complications

“…During atherogenesis, macrophage-derived elastases, such as elastolytic cathepsins or MMPs (MMP-2 and MMP-9), have been shown to degrade medial elastin, which favors calcification through an increase of elastin polarity that, in turn, enhances elastin affinity for calcium (Sasaki et al, unpublished data, 2011). 86,87 Recently, the data from cathepsin S-deficient mice have provided new insights into the pathobiology of arterial calcification and have aided the investigation of novel therapeutic strategies to reduce the onset of cardiovascular events and, thus, mortality (Table). 88 …”