Book of Abstracts - New Frontiers 2022

Abstracts of poster presentations

ADAPTIVE CHANGES IN THE LEFT HEART VENTRICLE IN A CHRONIC STRESS MODEL IN RATS

P. Karailiev, L. Karailievova, D. Jezova

Institude of experimental endocrinology, Biomedical research center SAS, Bratislava, Slovakia

Chronic stress is known to play a role in the development of cardiovascular diseases. However, stress exposure can induce adaptive changes and provide cardiovascular benefits as well. Previous studies using animal models have demonstrated that repeated stress stimuli can induce Akt kinase activation coupled with an increase of anti-apoptotic proteins (Bcl-2) and a down-regulation of pro-apoptotic proteins (cleaved caspase- 3) in rat hearts (Barteková et al., 2015). Another protein expressed in the heart with possibl e cardioprotective effects is the angiotensin converting enzyme 2 (ACE2), which cleaves angiotensin II into angiotensin 1-7, leading to decreased blood pressure. ACE2 in the heart during stress has not been studied as of yet. Interestingly, increased mitochondrial respiratory chain complex activities were observed under chronic stress, resulting in increased ATP production, which is crucial for cardiomyocyte activity (de Souza Mota et al., 2017). The mechanism underlying these changes is not yet understood. We hypothesise that the production of ACE2 and UQCRFS1, the catalytic component of mitochondrial respiratory chain complex III, is increased in the heart ventricle during chronic stress. Male Sprague Dawley rats were left undisturbed or exposed to chronic mild stress for five weeks. We measured the gene expression of both proteins and protein abundance of ACE2 by quantitative PCR and ELISA, respectively. Our results showed no significant changes in the mRNA or protein production of ACE2 in the left heart ventricle. We found a significant increase in UQCRFS1 mRNA production in the heart as a result of chronic stress exposure. Our results allow us to suggest that chronic stress most likely leads to adaptive changes in the composition of the mitochondrial respiratory chain in the left heart ventricle. How these changes affect the cardiovascular system during chronic stress needs further exploration.

Keywords: stress, heart, ACE2, UQCRFS1

Funding:This study was supported by the grant APVV-20-0202.

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