Abstract
Background and aims: The overall goal of this study was to determine the effects of MnSOD-deficiency on vascular structure and function in hypercholesterolemic mice. Previous work suggested that increases in mitochondrial-derived reactive oxygen species (ROS) can exacerbate vascular dysfunction and atherosclerosis. It remains unknown, however, how MnSOD-deficiency and local compensatory mechanisms impact atherosclerotic plaque composition. Methods and results: We used a hypercholesterolemic mouse model (ldlr−/−/ApoB100/100; LA), either wild-type for MnSOD (LA-MnSOD+/+) or MnSOD-haploinsufficient (LA-MnSOD+/-), that was fed a western diet for either 3 or 6 months. Consistent with previous reports, reductions of MnSOD did not significantly worsen hypercholesterolemia-induced endothelial dysfunction in the aorta. Critically, dramatic impairment of vascular function with Nox2 inhibition or catalase pretreatment suggested the presence of a significant NO-independent vasodilatory mechanism in LA-MnSOD+/- mice (e.g. H2O2). Despite remarkably well-preserved overall vascular relaxation, loss of mitochondrial antioxidant capacity in LA-MnSOD+/- mice significantly increased osteogenic signalling and vascular calcification compared to the LA-MnSOD+/+ littermates. Conclusions: Collectively, these data are the first to suggest that loss of mitochondrial antioxidant capacity in hypercholesterolemic mice results in dramatic upregulation of NADPH oxidase-derived H2O2. While this appears to be adaptive in the context of preserving overall endothelium-dependent relaxation and vascular function, these increases in ROS appear to be remarkably maladaptive and deleterious in the context of vascular calcification.
Original language | English (US) |
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Pages (from-to) | 31-37 |
Number of pages | 7 |
Journal | Atherosclerosis |
Volume | 331 |
DOIs | |
State | Published - Aug 2021 |
Keywords
- Atherosclerosis
- Mitochondria
- Oxidative stress
- Vascular calcification
- Vascular function
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine