Therapeutic inhibition of MPO stabilizes pre-existing high risk atherosclerotic plaque

Weiyu Chen; Sergey Tumanov; Stephanie M Y Kong; David Cheng; Erik Michaëlsson; André Bongers; Carl Power; Anita Ayer; Roland Stocker

doi:10.1016/j.redox.2022.102532

Therapeutic inhibition of MPO stabilizes pre-existing high risk atherosclerotic plaque

Redox Biol. 2022 Dec:58:102532. doi: 10.1016/j.redox.2022.102532. Epub 2022 Nov 5.

Authors

Weiyu Chen¹, Sergey Tumanov¹, Stephanie M Y Kong², David Cheng³, Erik Michaëlsson⁴, André Bongers⁵, Carl Power⁵, Anita Ayer², Roland Stocker⁶

Affiliations

¹ Heart Research Institute, The University of Sydney, Sydney, Australia; Faculty of Medicine and Health, The University of Sydney, Sydney, Australia.
² Heart Research Institute, The University of Sydney, Sydney, Australia.
³ Victor Chang Cardiac Research Institute, Sydney, Australia.
⁴ Early Clinical Development, Research and Early Development, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden.
⁵ Biological Resources Imaging Laboratory, University of New South Wales, Sydney Australia.
⁶ Heart Research Institute, The University of Sydney, Sydney, Australia; School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia. Electronic address: roland.stocker@hri.org.au.

Abstract

Currently there are no established therapies to treat high-risk patients with unstable atherosclerotic lesions that are prone to rupture and can result in thrombosis, abrupt arterial occlusion, and a precipitous infarction. Rather than being stenotic, rupture-prone non-occlusive plaques are commonly enriched with inflammatory cells and have a thin fibrous cap. We reported previously that inhibition of the pro-inflammatory enzyme myeloperoxidase (MPO) with the suicide inhibitor AZM198 prevents formation of unstable plaque in the Tandem Stenosis (TS) mouse model of plaque instability. However, in our previous study AZM198 was administered to animals before unstable plaque was present and hence it did not test the significant unmet clinical need present in high-risk patients with vulnerable atherosclerosis. In the present study we therefore asked whether pharmacological inhibition of MPO with AZM198 can stabilize pre-existing unstable lesions in an interventional setting using the mouse model of plaque instability. In vivo molecular magnetic resonance imaging of arterial MPO activity using bis-5-hydroxytryptamide-DTPA-Gd and histological analyses revealed that arterial MPO activity was elevated one week after TS surgery, prior to the presence of unstable lesions observed two weeks after TS surgery. Animals with pre-existing unstable plaque were treated with AZM198 for one or five weeks. Both short- and long-term intervention effectively inhibited arterial MPO activity and increased fibrous cap thickness, indicative of a more stable plaque phenotype. Plaque stabilization was observed without AZM198 affecting the arterial content of Ly6B.2⁺- and CD68⁺-cells and MPO protein. These findings demonstrate that inhibition of arterial MPO activity converts unstable into stable atherosclerotic lesions in a preclinical model of plaque instability and highlight the potential therapeutic potency of MPO inhibition for the management of high-risk patients and the development of novel protective strategies against cardiovascular diseases.

Keywords: AZM198; Atherosclerosis; MPO-Gd; Magnetic resonance imaging (MRI); Myeloperoxidase (MPO); Myeloperoxidase inhibitor; Unstable plaque.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Atherosclerosis* / drug therapy
Cardiovascular Diseases* / prevention & control
Disease Models, Animal
Mice
Peroxidase* / antagonists & inhibitors
Plaque, Atherosclerotic* / drug therapy
Plaque, Atherosclerotic* / pathology

Substances

Peroxidase