Cardioprotective effect of Beclin-1 in myocardial ischemia-reperfusion injury in female and male mice

Heart attacks are a leading cause of death. A heart attack occurs when a blockage, such as a blood clot, stops blood flow in a coronary artery and heart muscle cells die. Restoring blood flow (reperfusion) is essential, but the sudden return of blood can also damage the already vulnerable myocardium. This process is called myocardial ischemia/reperfusion (mI/R) injury. During mI/R, autophagy is activated as a response that helps clear damaged proteins and cellular debris from the injured myocardium. The gene Beclin-1 is a key regulator of this process. It is required for initiating autophagy and forming autophagosomes. However, its precise role in recovery after mI/R injury remains unknown. We hypothesize that Beclin-1 is important for recovery from mI/R injury, and that loss of Beclin-1 will impair this repair process. To investigate this, we used the ex vivo Langendorff heart perfusion technique in male and female wild-type C57BL/6 (WT) mice and Bcl2AAA knock-in mice. Bcl2AAA mice carry alanine substitutions at three phosphorylation sites in Bcl2 (Thr69Ala, Ser70Ala, and Ser84Ala), which prevent dissociation of the Bcl2-Beclin-1 complex and thereby reduce Beclin-1 function. Mice were euthanized by CO 2 overdose followed by cervical dislocation. Hearts were rapidly excised, cannulated, and perfused with Krebs–Henseleit buffer. Each heart underwent 20 minutes of baseline recording, 20 minutes of global ischemia, and 30 minutes of reperfusion. Cardiac recovery was assessed using Left Ventricular Developed Pressure (LVDP) after 30 minutes of reperfusion, expressed as a percentage of pre-ischemic baseline (%LVDP), measured with the ISO Heart (Harvard Apparatus). We found that Bcl2AAA male hearts showed significantly better recovery after mI/R injury (65.77% ± 1.63%; n = 13) versus WT males (54.54% ± 3.34%; n = 14; p< 0.05). In contrast, female Bcl2AAA hearts displayed impaired recovery (60.92% ± 3.15%; n = 16) versus WT females (81.28% ± 9.21%; n = 10; p< 0.05). These data indicate that Beclin-1 is required for optimal post-ischemic myocardial function, with a particularly important role in female hearts. Future microarray analyses will identify gene expression changes associated with Beclin-1-dependent recovery in female hearts during mI/R, helping to identify pathways important for post-mI/R repair and potential therapeutic targets. Funding: This work was supported by grants from the Canadian Institutes of Health Research (CIHR) and the Heart and Stroke Foundation, awarded to TAM and the International Masters Tuition Scholarship awarded to VK. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.