Title: Cardiovascular effects of sildenafil in experimental ischemia–reperfusion (reply to “Sildenafil-induced cardioprotection in rabbits, by Kukreja, R.C., Ockaili, R., Salloum, F., Xi, L.”)
Abstract:In their letter to the editor, Kukreja, Ockaili, Salloum and Xi comment on our recently published study in which intravenous application of 1.45 or 0.7 mg/kg sildenafil 30 min prior to coronary artery...In their letter to the editor, Kukreja, Ockaili, Salloum and Xi comment on our recently published study in which intravenous application of 1.45 or 0.7 mg/kg sildenafil 30 min prior to coronary artery occlusion did not reduce myocardial infarct size in an experimental rabbit model of 30 min ischemia followed by 180 min of reperfusion [1].Since our results contrast with a recent investigation by this research group [2] that described pronounced infarct size reduction after pretreatment with sildenafil in a very similar model, the authors are ''puzzled by our negative findings''.Indeed, we appreciate the editorial decision from Cardiovascular Research to publish our results, as in these days publication bias in favor of positive results occasionally makes it difficult to publish ''negative findings''.We believe that the constructive debate, initiated by Kukreja et al. in this letter to the editor, may encourage this editorial policy.When comparing the mentioned investigations by Ockaili et al. [2] with our study, again-and we think that the extensive work from Dr. Kukreja's group on delayed cardioprotective effects of sildenafil [2,3] should be clearly differentiated from acute effects-we must reiterate the very similar study design in Ockaili's and our investigations.The only noticeable differences are the use of atropine when initiating anesthesia, the slightly lower body temperature in Ockaili's study, the use of pentobarbital for maintenance of anesthesia, and the higher infarct size in the control group in our study.Additionally, for preparation of a sildenafil solution, Ockaili et al. crushed Viagra tablets and dissolved them in saline, while we used the pure powder of sildenafil citrate.Whether these subtle differences in the study proto-Read More