Branched-chain amino acids-induced cardiac protection against ischemia/reperfusion injury

Satomi Shiho

Morio Atsushi

Miyoshi Hirotsugu

Nakamura Ryuji

Tsutsumi Rie

Sakaue Hiroshi

Yasuda Toshimichi

Saeki Noboru

Tsutsumi Yasuo M.

Life Sciences

Aims: Amino acids, especially branched chain amino acids (BCAAs), have important regulatory roles in protein synthesis. Recently studies revealed that BCAAs protect against ischemia/reperfusion (I/R) injury. We studied the signaling pathway and mitochondrial function affecting a cardiac preconditioning of BCAAs.
Main methods: An in vivo model of I/R injury was tested in control, mTOR+/+, and mTOR+/−. Mice were randomly assigned to receive BCAAs, rapamycin, or BCAAs + rapamycin. Furthermore, isolated cardiomyocytes were subjected to simulated ischemia and cell death was quantified. Biochemical and mitochondrial swelling assays were also performed.
Key findings: Mice treated with BCAAs had a significant reduction in infarct size as a percentage of the area at risk compared to controls (34.1 ± 3.9% vs. 44.7 ± 2.6%, P = 0.001), whereas mice treated with the mTOR inhibitor rapamycin were not protected by BCAA administration (42.2 ± 6.5%, vs. control, P = 0.015). This protection was not detected in our hetero knockout mice of mTOR. Western blot analysis revealed no change in AKT signaling whereas activation of mTOR was identified. Furthermore, BCAAs prevented swelling which was reversed by the addition of rapamycin. In myocytes undergoing simulated I/R, BCAA treatment significantly preserved cell viability (71.7 ± 2.7% vs. 34.5 ± 1.6%, respectively, p < 0.0001), whereas rapamycin prevented this BCAA-induced cardioprotective effect (43.5 ± 3.4% vs. BCAA, p < 0.0001).
Significance: BCAA treatment exhibits a protective effect in myocardial I/R injury and that mTOR plays an important role in this preconditioning effect.

Amino acid

Ischemia

Reperfusion

mTOR

Mitochondria

eng

Elsevier

© 2020. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

This is not the published version. Please cite only the published version. この論文は出版社版ではありません。引用の際には出版社版をご確認、ご利用ください。

[ISSN] 0024-3205

[DOI] 10.1016/j.lfs.2020.117368

[PMID] 32001270

[DOI] https://doi.org/10.1016/j.lfs.2020.117368