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(Circulation Research. 2006;99:e11.)
© 2006 American Heart Association, Inc.

Letters to the Editor

Is This Truly Ischemic Preconditioning?

Derek J. Hausenloy, Mihaela M. Mocanu, Derek M. Yellon

The Hatter Cardiovascular Institute, University College London Hospital and Medical School United Kingdom

An extract of the first 250 words of the full text is provided, because this article has no abstract.

To the Editor:

In a recent article, Cai and Semenza¹ claim to have demonstrated a role for modulation of PTEN activity in the setting of ischemic preconditioning (IPC), using an isolated perfused rat heart. We believe the findings of this study are potentially of great significance as this study is the first to implicate PTEN in myocardial ischemia–reperfusion injury. However, we question the model of IPC used in this study. Specifically we question whether 15 minutes of myocardial ischemia followed by 30 minutes of myocardial reperfusion actually qualifies as an IPC protocol in the isolated perfused rat heart.

Ischemic preconditioning as initially described by Murry and colleagues² comprised 5 minute episodes of myocardial ischemia and reperfusion in the in vivo dog heart. The standard accepted IPC protocol in the isolated perfused rat heart comprises either 1 or 2 cycles of 5 minutes of ischemia followed by either 5 or 10 minutes of reperfusion before a 30-minute sustained lethal episode of ischemia and 120 minutes of reperfusion. Importantly, the preconditioning ischemia is short-lived and non-lethal.

In their study, Cai and Semenza¹ used an IPC protocol comprising 15 minutes of myocardial ischemia, which in this model may be expected to induce lethal myocardial ischemia or severe reperfusion-induced arrhythmias. The authors remark that in most species a preconditioning ischemic episode of 15 minutes followed by reperfusion is sufficient for protection, but we are unaware of any studies using such an IPC protocol. In addition, they cite articles by Barbosa and colleagues³ and Schulz . . . [Full Text of this Article]

This article has been cited by other articles:

				Z. Cai and G. L. Semenza Is 15-min Ischemia too Lethal to Be an Ischemic Preconditioning Stimulus? Circ. Res., November 10, 2006; 99(10): e86 - e86. [Full Text] [PDF]