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Published in

American Physiological Society, American Journal of Physiology - Heart and Circulatory Physiology, 2024

DOI: 10.1152/ajpheart.00424.2024

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The effects of chronic stress on rat heart function following regional ischemia: a sex-dependent investigation

This paper was not found in any repository, but could be made available legally by the author.
This paper was not found in any repository, but could be made available legally by the author.

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Abstract

Chronic psychosocial stress is a recognized, yet understudied risk factor for heart disease, with potential sex-specific effects. We investigated whether chronic stress triggers sex-dependent cardiac dysfunction in isolated Wistar rat hearts subjected to ischemia-reperfusion injury. The experimental cohort underwent 1 hour of daily restraint stress for four weeks versus matched controls, followed by euthanasia (sodium pentobarbitone) and heart excision for ex vivo perfusion. Blood analysis revealed sex-specific alterations in stress hormones and inflammatory markers. Compared to controls, chronic restraint stress (CRS) males displayed decreased plasma brain-derived neurotrophic factor (BDNF) levels (p<0.05), while CRS females exhibited elevated plasma adrenocorticotropic hormone (ACTH) (p<0.01) and reduced corticosterone (p<0.001) alongside lower serum estradiol (p<0.001) and estradiol/ progesterone ratio (p<0.01). Of note, CRS females showed increased serum cardiac troponin T (p<0.05) and tumor necrosis factor-alpha (TNF-a) (p<0.01) with suppressed interleukin (IL)-1a, IL-1β, IL-6, and IL-10 levels (p<0.05) when compared to controls. Ex vivo Langendorff perfusions revealed that CRS female hearts displayed impaired post-ischemic functional recovery for baseline stroke volume (p<0.01), work performance (p<0.05), aortic output (p<0.05), coronary flow (p<0.01), and overall cardiac output (p<0.01) when compared to matched controls and CRS males (p<0.05). Our findings reveal intriguing sex-specific responses at both the systemic and functional levels in stressed hearts. Here, the dysregulation of stress hormones, pro-inflammatory state, and potential underlying cardiomyopathy in females following the stress protocol renders them more prone to damage following myocardial ischemia. This study emphasizes the importance of incorporating sex as a biological variable in cardiac research focusing on stress-related cardiomyopathy.