Molecular imaging of MMP activity discriminates unstable from stable plaque phenotypes in shear-stress induced murine atherosclerosis

Abstract

PurposeAs atherosclerotic plaque ruptures are the primary cause of ischaemic events, their preventive identification by imaging remains a clinical challenge. Matrix metalloproteinases (MMP) are involved in plaque progression and destabilisation and are therefore promising targets to characterize rupture-prone unstable plaques. This study aims at evaluating MMP imaging to discriminate unstable from stable plaque phenotypes.MethodsApoE deficient mice (ApoE-/-) on a high cholesterol diet underwent implantation of a tapered cuff around the right common carotid artery (CCA) inducing a highly inflamed atherosclerotic plaque upstream (US) and a more stable plaque phenotype downstream (DS) of the cuff. 8 weeks after surgery, the MMP inhibitor-based photoprobe Cy5.5-AF443 was administered i.v. 3h prior to in situ and ex vivo fluorescence reflectance imaging of the CCAs. Thereafter, CCAs were analysed regarding plaque size, presence of macrophages, and MMP-2 and MMP-9 concentrations by immunohistochemistry and ELISA.ResultsWe found a significantly higher uptake of Cy5.5-AF443 in US as compared to DS plaques in situ (1.29 vs. 1.06 plaque-to-background ratio; p<0.001), which was confirmed by ex vivo measurements. Immunohistochemistry revealed a higher presence of macrophages, MMP-2 and MMP-9 in US compared to DS plaques. Accordingly, MMP-2 concentrations were significantly higher in US plaques (47.2±7.6 vs. 29.6±4.6 ng/mg; p<0.05).ConclusionsIn the ApoE-/- cuff model MMP-2 and MMP-9 activities are significantly higher in upstream low shear stress-induced unstable atherosclerotic plaques as compared to downstream more stable plaque phenotypes. MMP inhibitor-based fluorescence molecular imaging allows visualization of these differences in shear stress-induced atherosclerosis.

Ginsenoside Rg3 Alleviates ox-LDL Induced Endothelial Dysfunction and Prevents Atherosclerosis in ApoE−/− Mice by Regulating PPARγ/FAK Signaling Pathway

“…Activation of FAK can sensitize the non-adhesive-dependent atherogenic matrix metalloproteinases pathway (MMP) (Alford et al, 2017), including MMP-2 and MMP-9, which can stimulate the vulnerability of atherosclerotic plaques (Seifert et al, 2018), our study showed the same trend of MMP-2/9 in ox-LDL stimulated HUVECs, and Rg3 inhibit the MMP-2/9 expression, while GW9662 inhibited the effect of Rg3 on MMP-2 and MMP-9 ( Figure 3A). Furthermore, the activation of NF-kB into the nucleus increased significantly in HUVECs after stimulating with ox-LDL, and the nucleus sustained more damage than normal HUVECs ( Figures 3B, C).…”

“…MMP is one of the important pathways significantly affected by FAK activation (Alford et al, 2017). MMP-2/9 can increase the instability of atherosclerotic plaque (Seifert et al, 2018); our results showed that the expression of MMP-2 and MMP-9 were enhanced in ox-LDLstimulated HUVECs, and GW9662 repressed the inhibitory effect of Rg3 on MMP-2 and MMP-9, study showed that NF-kB activation was achieved by up-regulating FAK expression via RSK/IKKb activation in ox-LDL-stimulated endothelial cells (Yurdagul et al, 2016), and Rg3 significantly inhibited NF-kB activation by regulating the PPARg/FAK pathway in ox-LDLstimulated endothelial cells, along with repressed IL-6 and MCP-1 mRNA levels which is inflammatory factor promoting monocyte infiltration. Guo et al confirmed that Rg3 can inhibit the inflammatory macrophages infiltration and injury of induced by persistent hyperglycemia by up-regulating the expression of PPARg (Guo et al, 2018), and PPARg is the target of anti-diabetes, our study further confirmed Rg3 not only improve hyperglycemia complicated with AS, but also has a good effect on AS caused by dyslipidemia by regulating PPARg.…”

Blocking matrix metalloproteinase-mediated syndecan-4 shedding restores the endothelial glycocalyx and glomerular filtration barrier function in early diabetic kidney disease

“…Future work will determine the relative importance of MMP2 or -9 and their potential cellular sources. We have previously shown in vitro that MMPs produced by GEC are sufficient to cause SDC4 shedding, 16 but circulating immune cells also produce MMPs, 71,72 which may be equally or more important in diabetes in vivo. There a number of upstream signaling pathways (MAP kinases, 73,74 nuclear factor kB, and protein kinase C 65 ) that have been implicated in MMP activation, but there is little context-specific information, and further work in this area may identify further targets for therapeutic intervention.…”

Matrix Metalloproteinases as Biomarkers of Atherosclerotic Plaque Instability

“…High levels of MMP-8 in the carotid plaque correlate with an unstable plaque composition and systemic cardiovascular outcome [147]. Seifert et al confirmed that MMP-2 and MMP-9 activities was significantly higher in the ApoE-/-cuff model in unstable atherosclerotic plaques as compared to downstream more stable plaque phenotypes [148]. Increased plasma MMP-9 and TIMP-1 levels have been demonstrated in the coronary circulation in patients with acute coronary syndrome (ACS), which suggests active process of plaque rupture and future risk of cardiovascular events [149].…”