Research Article Effects of Cardiac Hypertrophy, Diabetes, Aging, and Pregnancy on the Cardioprotective Effects of Postconditioning in Male and Female Rats Fawzi Babiker , 1 Aishah Al-Jarallah , 2 and Mariam Al-Awadi 1 1 Department of Physiology, Faculty of Medicine, Health Science Center, Kuwait University, Jabriya, Kuwait 2 Biochemistry, Faculty of Medicine, Health Science Center, Kuwait University, Jabriya, Kuwait Correspondence should be addressed to Fawzi Babiker; fawzi.b@hsc.edu.kw Received 15 October 2018; Revised 12 February 2019; Accepted 25 March 2019; Published 6 May 2019 Academic Editor: Vincenzo Russo Copyright © 2019 Fawzi Babiker et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. Aging, left ventricular hypertrophy (LVH), diabetes mellitus, and pregnancy are well-recognized risk factors that increase the prevalence of cardio-ischemic events and are linked to poor clinical recovery following acute myocardial infarction. e coexistence of these risk factors with ischemic heart disease (IHD) deteriorates disease prognosis and could potentially lead to fatal arrhythmias and heart failure. e objective of this study was to investigate the vulnerability of hearts with aging, LVH, diabetes, and pregnancy to ischemic insult and their response to pacing postconditioning- (PPC-) induced heart protection. Methods. Hearts isolated from aged, spontaneously hypertensive and diabetic male and female rats and hearts from pregnant female rats (n � 8 per group) were subjected to coronary occlusion followed by reperfusion using a modified Langendorff system. Hemodynamics data were computed digitally, and cardiac damage was accessed by measurements of infarct size and cardiac enzyme release. Results. ere were no significant differences in the vulnerability of all hearts to ischemic insult compared to their respective controls. PPC improved cardiac hemodynamics and reduced infarct size and cardiac enzyme release in hearts isolated from aged and spontaneously hypertensive female rats and female rats with hypertrophied hearts subjected to PPC (P < 0.001). Aged or hypertrophied male hearts were not protected by PPC maneuver. Moreover, the protective effects of PPC were lost in diabetic male and female hearts although retained in hearts from pregnant rats. Conclusions. We demonstrate that aging, LVH, diabetes mellitus, and pregnancy do not affect cardiac vulnerability to ischemic insult. Moreover, PPC mediates cardioprotection in a gender-specific manner in aged and spontaneously hypertensive rats. Diabetes mellitus provokes the protective effects of PPC on both genders equally. Finally, we demonstrate that PPC is a new cardioprotective maneuver in hearts from pregnant female rats. 1.Background Ischemic heart disease (IHD) remains a global health concern, and acute myocardial infarction continues to be a leading cause of death [1]. Restriction of coronary blood supply leads to myocardial infarction which is the primary determinant of disease prognosis [1]. e infarct size and disease outcome can remarkably be improved by restoration of blood flow by reperfusion [2]. However, reperfusion itself can be devastating resulting in significant damage within the ischemia-affected area [2]. Several cardioprotective strate- gies have been developed to limit the destructive effects of ischemia/reperfusion (I/R) injury on the myocardium. ese include, but are not limited to, the application of brief sublethal ischemic episodes at the beginning of reperfu- sion on-site or a distant vascular bed (ischemic post- conditioning and remote ischemic postconditioning, respectively) [3, 4]. More recently, a modification of the remote postconditioning maneuver has been introduced which involves changing myocardial stretch pattern via remote electrical stimulation of the heart chambers (pacing postconditioning (PPC)) [5]. We have reported that PPC is an effective protective postconditioning maneuver against I/R injury in experimental animals [5–7]. We have further investigated the molecular mechanisms involved in PPC-induced cardiac protection [8–10]. e first clinical Hindawi Cardiology Research and Practice Volume 2019, Article ID 3403959, 12 pages https://doi.org/10.1155/2019/3403959