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(Circulation. 2007;116:231.)
© 2007 American Heart Association, Inc.
Issue Highlights
An extract of the first 250 words of the full text is provided, because this article has no abstract. |
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PHOSPHODIESTERASE TYPE 5 IS HIGHLY EXPRESSED IN THE HYPERTROPHIED HUMAN RIGHT VENTRICLE, AND ACUTE INHIBITION OF PHOSPHODIESTERASE TYPE 5 IMPROVES CONTRACTILITY, by Nagendran et al. |
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The beneficial effects of phosphodiesterase type 5 (PDE5) inhibitors in patients with pulmonary hypertension have been attributed to the inhibitors’ vasodilatory and antiproliferative actions in the pulmonary vasculature. Nagendran et al found that PDE5, which is not expressed in normal myocardium, is upregulated in failing human right ventricular myocardium and also in hypertrophied right ventricle in a rat. PDE5 inhibition with sildenafil increased contractility in both a perfused heart preparation and in isolated cardiac myocytes from hypertrophied, but not normal, right ventricle. The investigators further relate this inotropic effect to cGMP-mediated inhibition of PDE3, which in turn increases cAMP levels. These unanticipated actions of PDE5 inhibition in the hypertrophied right ventricle may contribute to the clinical benefits of PDE5 inhibitors. See p 238 (editorial p 233).
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MOLECULAR IMAGING OF INFLAMMATION IN ATHEROSCLEROSIS WITH TARGETED ULTRASOUND DETECTION OF VASCULAR CELL ADHESION MOLECULE-1, by Kaufmann et al. |
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The inflammatory component of atherosclerosis has proven difficult to evaluate in vivo. A noninvasive method of imaging the extent of vascular inflammation could help to define the initiation of atherosclerosis and potentially contribute to our understanding of plaque vulnerability. Kaufmann and colleagues use contrast-enhanced ultrasound to demonstrate that vascular cell adhesion molecule-1–targeted microbubbles attach to cultured endothelial cells and then further demonstrate attachment of these microbubbles to the aorta of apolipoprotein-E deficient mice. They also show the contrast-enhanced ultrasound videointensity correlates with the extent of vascular cell adhesion molecule-1–positive plaque formation. This provocative animal study is an exciting foray into this area of investigation and offers the potential to diagnose and track various stages of atherosclerosis with molecular imaging using contrast ultrasound. See
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