Reply
Refat Jabara, MD*,
Jinsheng Li, MD, PhD,
Keith Robinson, PhD, FACC
The observations of Dr. Kaneda and colleagues are clearly pertinent to the issues we raised in the Discussion section of our article (1). A common hypothesis generated by both of our results seems to be whether long-term (1 month post-implantation of sirolimus-eluting stents [SES] and even later) vasomotor dysfunction might be caused by a direct effect of the drug itself at very low concentration or secondary effects mediated through SES-triggered cellular interactions (for example, chronic SES-induced inflammation in the stented segment elaborating cytokines or other substances that impact endothelium-dependent relaxation). We suggest that the data currently available are inconclusive, because neither of these possibilities can yet be ruled out. Of interest however is that Jabs et al. (2) recently reported increased superoxide and p67(phox)/rac1 nicotinamide adenosine dinucleotide phosphate oxidase and reduced nitric oxide, along with vasomotor dysfunction, in the aortas of rats given a 1-week continuous infusion of sirolimus. Their report did not include a histological assessment, but the recruitment of inflammatory cells would seem to be a plausible potential mechanism underlying these phenomena.
* Saint Joseph's Cardiovascular Research Institute/Saint Joseph's Hospital of Atlanta, 5673 Peachtree Dunwoody Road, Suite 675, Atlanta, Georgia 30342 (Email: rjabara{at}sjha.org).
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REFERENCES
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- Li J, Jabara R, Pendyala R, et al. Abnormal vasomotor function of porcine coronary arteries distal to sirolimus-eluting stents J Am Coll Cardiol Intv 2008;1:279-285.[Abstract/Free Full Text]
- Jabs A, Göbel S, Wenzel P, et al. Sirolimus-induced vascular dysfunction. Increased mitochondrial and nicotinamide adenosine dinucleotide phosphate oxidase-dependent superoxide production and decreased vascular nitric oxide formation. J Am Coll Cardiol 2008;51:2130-2138.[Abstract/Free Full Text]
Related Article
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Tissue Sirolimus Levels of Distal Vessel, Stented Myocardium, and Distal Myocardium
- Hideaki Kaneda, Alan Yeung, and Fumiaki Ikeno
J. Am. Coll. Cardiol. Intv. 2008 1: 595.
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