(Circulation. 2004;110:1178-1179.)
© 2004 American Heart Association, Inc.
Editorial |
From the Division of Cardiology, Departments of Medicine and Pathology, The Johns Hopkins University School of Medicine, Baltimore, Md.
Correspondence to Charles J. Lowenstein, 950 Ross Building, The Johns Hopkins University School of Medicine, 720 Rutland Ave, Baltimore, MD 21205. E-mail clowenst@jhmi.edu
Key Words: Editorials myocarditis inflammation oxygen
An extract of the first 250 words of the full text is provided, because this article has no abstract. |
Levels of reactive oxygen species (ROS) are tightly regulated in mammalian cells. A variety of enzymes produce ROS, including NAD(P)H oxidase, xanthine oxidase, glucose oxidase, myeloperoxidase, the family of nitric oxide synthases, and mitochondrial enzymes.14 Low levels of ROS such as superoxide or hydrogen peroxide regulate highly specific targets.5,6 In the cardiovascular system, for example, ROS serve as signaling molecules, mediating vascular endothelial growth factor signal transduction, activating matrix metalloproteinases, and regulating cell cycle phosphatases. Host defenses that protect against oxidative stress include small antioxidant molecules such as ascorbate,
-tocopherol, glutathione, and thioredoxin (Trx), as well as antioxidant enzymes such as superoxide dismutase, catalase, paraoxonase, glutathione reductase, glutathione peroxidase, and Trx reductase.
See p 1276
However, excessive oxidative stresscaused by either increased ROS production or inadequate antioxidant defensescan lead to cardiovascular diseases. For example, genetic deficiency of glutathione peroxidase-1 is associated with increased levels of vascular hydrogen peroxide and arterial thrombosis.7,8 Another example of an imbalance in oxidant stress occurs when elevated levels of angiotensin II trigger excess ROS production by the vascular NAD(P)H oxidase Mox1, contributing to decreased nitric oxide bioavailability, endothelial dysfunction, and atherogenesis.9,10 Additionally, increased levels of ROS generated by xanthine oxidase in the heart impair cardiac energetics, playing a role in the development of cardiomyopathy.11,12 Finally, ROS may play a critical role in autoimmune myocarditis.
Autoimmunity is surprisingly common in patients with cardiomyopathy: Up to 20% of all idiopathic dilated cardiomyopathies are associated with autoantibodies and other autoimmune markers.13 Triggers of autoimmune myocarditis include (1) molecular
Related Article:
Circulation 2004 110: 1276-1283.
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