β-hydroxybutyrate administered at reperfusion reduces infarct size and preserves cardiac function by improving mitochondrial function through autophagy in male mice

Yuxin Chu, Yutao Hua, Lihao He, Jin He, Yunxi Chen, Jing Yang, Ismail Mahmoud, Fanfang Zeng, Xiaochang Zeng, Gloria A. Benavides, Victor M. Darley-Usmar, Martin E. Young, Scott W. Ballinger, Sumanth D. Prabhu, Cheng Zhang, Min Xie

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Ischemia/reperfusion (I/R) injury after revascularization contributes ∼50% of infarct size and causes heart failure, for which no established clinical treatment exists. β-hydroxybutyrate (β-OHB), which serves as both an energy source and a signaling molecule, has recently been reported to be cardioprotective when administered immediately before I/R and continuously after reperfusion. This study aims to determine whether administering β-OHB at the time of reperfusion with a single dose can alleviate I/R injury and, if so, to define the mechanisms involved. We found plasma β-OHB levels were elevated during ischemia in STEMI patients, albeit not to myocardial protection level, and decreased after revascularization. In mice, compared with normal saline, β-OHB administrated at reperfusion reduced infarct size (by 50%) and preserved cardiac function, as well as activated autophagy and preserved mtDNA levels in the border zone. Our treatment with one dose β-OHB reached a level achievable with fasting and strenuous physical activity. In neonatal rat ventricular myocytes (NRVMs) subjected to I/R, β-OHB at physiologic level reduced cell death, increased autophagy, preserved mitochondrial mass, function, and membrane potential, in addition to attenuating reactive oxygen species (ROS) levels. ATG7 knockdown/knockout abolished the protective effects of β-OHB observed both in vitro and in vivo. Mechanistically, β-OHB's cardioprotective effects were associated with inhibition of mTOR signaling. In conclusion, β-OHB, when administered at reperfusion, reduces infarct size and maintains mitochondrial homeostasis by increasing autophagic flux (potentially through mTOR inhibition). Since β-OHB has been safely tested in heart failure patients, it may be a viable therapeutic to reduce infarct size in STEMI patients.

Original languageEnglish
Pages (from-to)31-44
Number of pages14
JournalJournal of Molecular and Cellular Cardiology
Volume186
DOIs
StatePublished - Jan 2024

Keywords

  • Autophagy
  • Ischemia-reperfusion injury
  • Mitochondria
  • β-hydroxybutyrate

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