Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of
nitric oxide synthase, is increasingly recognized as a novel
biomarker in
cardiovascular disease. To date, it remains unclear whether elevated ADMA levels are merely associated with cardiovascular risk or whether this molecule is of functional relevance in the pathogenesis of atherosclerotic
vascular disease. To clarify this issue, we crossed
dimethylarginine dimethylaminohydrolase (DDAH) transgenic mice that overexpress the human
isoform 1 of the ADMA degrading
enzyme DDAH into
ApoE-deficient mice to generate
ApoE(-/-)/hDDAH1(+/-) mice. In these mice, as well as
ApoE(-/-) wild-type littermates,
atherosclerosis within the aorta as well as vascular function of aortic ring preparations was assessed. We report here that overexpression of hDDAH1 reduces plaque formation in
ApoE(-/-) mice by lowering ADMA. The extent of
atherosclerosis closely correlated with plasma ADMA levels in male but not female mice fed either a standard rodent chow or an atherogenic diet. Functional analysis of aortic ring preparations revealed improved endothelial function in mice overexpressing hDDAH1. Our findings provide proof-of-principle that ADMA plays a causal role as a culprit molecule in
atherosclerosis and support recent evidence indicating a functional relevance of DDAH
enzymes in genetic mouse models. Together, these results demonstrate that pharmacological interventions targeting the ADMA/DDAH pathway may represent a novel approach in the prevention and management of
cardiovascular diseases.