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Porphyrin-Based SOD Mimic MnTnBu OE -2-PyP5+ Inhibits Mechanisms of Aortic Valve Remodeling in Human and Murine Models of Aortic Valve Sclerosis.

ABSTRACT: Background Aortic valve sclerosis ( AVS c), the early asymptomatic presentation of calcific aortic valve (AV) disease, affects 25% to 30% of patients aged >65 years. In vitro and ex vivo experiments with antioxidant strategies and antagonists of osteogenic differentiation revealed that AVS c is reversible. In this study, we characterized the underlying changes in the extracellular matrix architecture and valve interstitial cell activation in AVSc and tested in vitro and in vivo the activity of a clinically approved SOD (superoxide dismutase) mimic and redox-active drug MnTnBu OE -2-PyP5+ ( BMX -001). Methods and Results After receiving informed consent, samples from patients with AVS c, AV stenosis, and controls were collected. Uniaxial mechanical stimulation and in vitro studies on human valve interstitial cells were performed. An angiotensin II chronic infusion model was used to impose AV thickening and remodeling. We characterized extracellular matrix structures by small-angle light scattering, scanning electron microscopy, histology, and mass spectrometry. Diseased human valves showed altered collagen fiber alignment and ultrastructural changes in AVS c, accumulation of oxidized cross-linking products in AV stenosis, and reversible expression of extracellular matrix regulators ex vivo. We demonstrated that MnTnBu OE -2-PyP5+ inhibits human valve interstitial cell activation and extracellular matrix remodeling in a murine model (C57 BL /6J) of AVS c by electron microscopy and histology. Conclusions AVS c is associated with architectural remodeling despite marginal effects on the mechanical properties in both human and mice. MnTnBu OE -2-PyP5+ controls AV thickening in a murine model of AVS c. Because this compound has been approved recently for clinical use, this work could shift the focus for the treatment of calcific AV disease, moving from AV stenosis to an earlier presentation ( AVS c) that could be more responsive to medical therapies.

SUBMITTER: Anselmo W

PROVIDER: S-EPMC6474974 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature

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Porphyrin-Based SOD Mimic MnTnBu OE -2-PyP<sup>5+</sup> Inhibits Mechanisms of Aortic Valve Remodeling in Human and Murine Models of Aortic Valve Sclerosis.

Anselmo Wanda W Branchetti Emanuela E Grau Juan B JB Li Gen G Ayoub Salma S Lai Eric K EK Rioux Nancy N Tovmasyan Artak A Fortier Jacqueline H JH Sacks Michael S MS Batinic-Haberle Ines I Hazen Stanley L SL Levy Robert J RJ Ferrari Giovanni G

Journal of the American Heart Association 20181001 20

Background Aortic valve sclerosis ( AVS c), the early asymptomatic presentation of calcific aortic valve (AV) disease, affects 25% to 30% of patients aged >65 years. In vitro and ex vivo experiments with antioxidant strategies and antagonists of osteogenic differentiation revealed that AVS c is reversible. In this study, we characterized the underlying changes in the extracellular matrix architecture and valve interstitial cell activation in AVSc and tested in vitro and in vivo the activity of a ...[more]

PMID: 30371255

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Project description:The cationic, ortho Mn(III) N-alkylpyridylporphyrins (alkyl=ethyl, E, and n-hexyl, nHex) MnTE-2-PyP(5+) (AEOL10113, FBC-007) and MnTnHex-2-PyP(5+) have proven efficacious in numerous in vivo animal models of diseases having oxidative stress in common. The remarkable therapeutic efficacy observed is due to their: (1) ability to catalytically remove O2(•-) and ONOO(-) and other reactive species; (2) ability to modulate redox-based signaling pathways; (3) accumulation within critical cellular compartments, i.e., mitochondria; and (4) ability to cross the blood-brain barrier. The similar redox activities of both compounds are related to the similar electronic and electrostatic environments around the metal active sites, whereas their different bioavailabilities are presumably influenced by the differences in lipophilicity, bulkiness, and shape. Both porphyrins are water soluble, but MnTnHex-2-PyP(5+) is approximately 4 orders of magnitude more lipophilic than MnTE-2-PyP(5+), which should positively affect its ability to pass through biological membranes, making it more efficacious in vivo at lower doses. To gain insight into the in vivo tissue distribution of Mn porphyrins and its impact upon their therapeutic efficacy and mechanistic aspects of action, as well as to provide data that would ensure proper dosing regimens, we conducted comprehensive pharmacokinetic (PK) studies for 24h after single-dose drug administration. The porphyrins were administered intravenously (iv), intraperitoneally (ip), and via oral gavage at the following doses: 10mg/kg MnTE-2-PyP(5+) and 0.5 or 2mg/kg MnTnHex-2-PyP(5+). Drug levels in plasma and various organs (liver, kidney, spleen, heart, lung, brain) were determined and PK parameters calculated (Cmax, C24h, tmax, and AUC). Regardless of high water solubility and pentacationic charge of these Mn porphyrins, they are orally available. The oral availability (based on plasma AUCoral/AUCiv) is 23% for MnTE-2-PyP(5+) and 21% for MnTnHex-2-PyP(5+). Despite the fivefold lower dose administered, the AUC values for liver, heart, and spleen are higher for MnTnHex-2-PyP(5+) than for MnTE-2-PyP(5+) (and comparable for other organs), clearly demonstrating the better tissue penetration and tissue retention of the more lipophilic MnTnHex-2-PyP(5+).

Project description:BACKGROUND:Left ventricular (LV) hypertrophy, a key process in human cardiac disease, results from cellular (hypertrophy) and extracellular matrix expansion (interstitial fibrosis). OBJECTIVES:This study sought to investigate whether human myocardial interstitial fibrosis in aortic stenosis (AS) is plastic and can regress. METHODS:Patients with symptomatic, severe AS (n = 181; aortic valve area index 0.4 ± 0.1 cm2/m2) were assessed pre-aortic valve replacement (AVR) by echocardiography (AS severity, diastology), cardiovascular magnetic resonance (CMR) (for volumes, function, and focal or diffuse fibrosis), biomarkers (N-terminal pro-B-type natriuretic peptide and high-sensitivity troponin T), and the 6-min walk test. CMR was used to measure the extracellular volume fraction (ECV), thereby deriving matrix volume (LV mass × ECV) and cell volume (LV mass × [1 - ECV]). Biopsy excluded occult bystander disease. Assessment was repeated at 1 year post-AVR. RESULTS:At 1 year post-AVR in 116 pacemaker-free survivors (age 70 ± 10 years; 54% male), mean valve gradient had improved (48 ± 16 mm Hg to 12 ± 6 mm Hg; p < 0.001), and indexed LV mass had regressed by 19% (88 ± 26 g/m2 to 71 ± 19 g/m2; p < 0.001). Focal fibrosis by CMR late gadolinium enhancement did not change, but ECV increased (28.2 ± 2.9% to 29.9 ± 4.0%; p < 0.001): this was the result of a 16% reduction in matrix volume (25 ± 9 ml/m2 to 21 ± 7 ml/m2; p < 0.001) but a proportionally greater 22% reduction in cell volume (64 ± 18 ml/m2 to 50 ± 13 ml/m2; p < 0.001). These changes were accompanied by improvement in diastolic function, N-terminal pro-B-type natriuretic peptide, 6-min walk test results, and New York Heart Association functional class. CONCLUSIONS:Post-AVR, focal fibrosis does not resolve, but diffuse fibrosis and myocardial cellular hypertrophy regress. Regression is accompanied by structural and functional improvements suggesting that human diffuse fibrosis is plastic, measurable by CMR and a potential therapeutic target. (Regression of Myocardial Fibrosis After Aortic Valve Replacement; NCT02174471).

Dataset Information

Porphyrin-Based SOD Mimic MnTnBu OE -2-PyP5+ Inhibits Mechanisms of Aortic Valve Remodeling in Human and Murine Models of Aortic Valve Sclerosis.

Publications

Porphyrin-Based SOD Mimic MnTnBu OE -2-PyP<sup>5+</sup> Inhibits Mechanisms of Aortic Valve Remodeling in Human and Murine Models of Aortic Valve Sclerosis.

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