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Deficiency of superoxide dismutase promotes cerebral vascular hypertrophy and vascular dysfunction in hyperhomocysteinemia
Journal article   Open access   Peer reviewed

Deficiency of superoxide dismutase promotes cerebral vascular hypertrophy and vascular dysfunction in hyperhomocysteinemia

Sanjana Dayal, Gary L Baumbach, Erland Arning, Teodoro Bottiglieri, Frank M Faraci and Steven R Lentz
PloS one, Vol.12(4), pp.e0175732-e0175732
2017
DOI: 10.1371/journal.pone.0175732
PMCID: PMC5393600
PMID: 28414812
url
https://doi.org/10.1371/journal.pone.0175732View
Published (Version of record) Open Access

Abstract

There is an emerging consensus that hyperhomocysteinemia is an independent risk factor for cerebral vascular disease and that homocysteine-lowering therapy protects from ischemic stroke. However, the mechanisms by which hyperhomocysteinemia produces abnormalities of cerebral vascular structure and function remain largely undefined. Our objective in this study was to define the mechanistic role of superoxide in hyperhomocysteinemia-induced cerebral vascular dysfunction and hypertrophy. Unlike previous studies, our experimental design included a genetic approach to alter superoxide levels by using superoxide dismutase 1 (SOD1)-deficient mice fed a high methionine/low folate diet to produce hyperhomocysteinemia. In wild-type mice, the hyperhomocysteinemic diet caused elevated superoxide levels and impaired responses to endothelium-dependent vasodilators in cerebral arterioles, and SOD1 deficiency compounded the severity of these effects. The cross-sectional area of the pial arteriolar wall was markedly increased in mice with SOD1 deficiency, and the hyperhomocysteinemic diet sensitized SOD1-deficient mice to this hypertrophic effect. Analysis of individual components of the vascular wall demonstrated a significant increase in the content of smooth muscle and elastin. We conclude that superoxide is a key driver of both cerebral vascular hypertrophy and vasomotor dysfunction in this model of dietary hyperhomocysteinemia. These findings provide insight into the mechanisms by which hyperhomocysteinemia promotes cerebral vascular disease and ischemic stroke.
Blood Pressure Cerebrovascular Disorders - physiopathology Hyperhomocysteinemia - pathology Diet - adverse effects Cerebral Arteries - physiopathology Male Superoxide Dismutase-1 - deficiency Mice, 129 Strain Cerebrovascular Disorders - etiology Mice, Knockout Hyperhomocysteinemia - physiopathology Animals Cerebral Arteries - pathology Superoxide Dismutase-1 - genetics Superoxides - metabolism Female Mice Cerebrovascular Disorders - pathology Hyperhomocysteinemia - complications Disease Models, Animal Hypertrophy

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