Late-life restoration of mitochondrial function reverses cardiac dysfunction in old mice
- Oklahoma Medical Research Foundation, United States
- University of Washington, United States
- Buck Institute for Research on Aging, United States
- Pacific Northwest National Laboratory, United States
- University of Missouri, United States
- University of Arizona, United States
- Social Profit Network, United States
Abstract
Diastolic dysfunction is a prominent feature of cardiac aging in both mice and humans. We show here that 8-week treatment of old mice with the mitochondrial targeted peptide SS-31 (elamipretide) can substantially reverse this deficit. SS-31 normalized the increase in proton leak and reduced mitochondrial ROS in cardiomyocytes from old mice, accompanied by reduced protein oxidation and a shift towards a more reduced protein thiol redox state in old hearts. Improved diastolic function was concordant with increased phosphorylation of cMyBP-C Ser282 but was independent of titin isoform shift. Late-life viral expression of mitochondrial-targeted catalase (mCAT) produced similar functional benefits in old mice and SS-31 did not improve cardiac function of old mCAT mice, implicating normalizing mitochondrial oxidative stress as an overlapping mechanism. These results demonstrate that pre-existing cardiac aging phenotypes can be reversed by targeting mitochondrial dysfunction and implicate mitochondrial energetics and redox signaling as therapeutic targets for cardiac aging.
Data availability
Data file for metabolomic analysis (Table S1) and statistics of all proteins identified by proteomic analysis (Table S3) have been provided as supplementary materials.The raw mass spec files for proteomics analysis of S-glutathionylation were uploaded to MassIVE and can be accessed via the following link ftp://massive.ucsd.edu/MSV000085329/The raw mass spectrometry files for global proteomic analysis were uploaded to MassIVE and can be accessed via the following link ftp://massive.ucsd.edu/MSV000084961/The image files for ROS (Fig 2a and b) and senescence (Fig 4b and c) analyses can be accessed via the following link and were also included as supporting zip documents. https://www.dropbox.com/sh/0r50ew6xnpunc3t/AAA_HbJ0fQwhOUpDbI9Oq07va?dl=0
Article and author information
Author details
Funding
Glenn Foundation for Medical Research (Glenn/AFAR Postdoctoral Fellowship Program for Translational Research on Aging)
- Ying Ann Chiao
National Institute on Aging (5T32AG000057 Training Grant)
- Ying Ann Chiao
National Institute on Aging (K99/R00 AG051735)
- Ying Ann Chiao
National Institute on Aging (P01 AG001751)
- Peter Rabinovitch
National Institute on Aging (P30 AG013280)
- Peter Rabinovitch
Glenn Foundation for Medical Research (Glenn/AFAR Postdoctoral Fellowship Program for Translational Research on Aging)
- Huiliang Zhang
American Heart Association (CDA 19CDA34660311)
- Huiliang Zhang
National Heart, Lung, and Blood Institute (R35HL144998)
- Henk L Granzier
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All mice were handled according to the guidelines of the Institutional Animal Care and Use Committee of the University of Washington and approved IACUC Protocol # 2174-23 . Mice were housed at 20ºC in an AAALAC accredited facility under Institutional Animal Care Committee supervision.
Copyright
© 2020, Chiao et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Late-life restoration of mitochondrial function reverses cardiac dysfunction in old mice
eLife 9:e55513.
https://doi.org/10.7554/eLife.55513
Further reading
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Background:
Subarachnoid hemorrhage (SAH) is characterized by intense central inflammation, leading to substantial post-hemorrhagic complications such as vasospasm and delayed cerebral ischemia. Given the anti-inflammatory effect of transcutaneous auricular vagus nerve stimulation (taVNS) and its ability to promote brain plasticity, taVNS has emerged as a promising therapeutic option for SAH patients. However, the effects of taVNS on cardiovascular dynamics in critically ill patients, like those with SAH, have not yet been investigated. Given the association between cardiac complications and elevated risk of poor clinical outcomes after SAH, it is essential to characterize the cardiovascular effects of taVNS to ensure this approach is safe in this fragile population. Therefore, this study assessed the impact of both acute and repetitive taVNS on cardiovascular function.
Methods:
In this randomized clinical trial, 24 SAH patients were assigned to either a taVNS treatment or a sham treatment group. During their stay in the intensive care unit, we monitored patient electrocardiogram readings and vital signs. We compared long-term changes in heart rate, heart rate variability (HRV), QT interval, and blood pressure between the two groups. Additionally, we assessed the effects of acute taVNS by comparing cardiovascular metrics before, during, and after the intervention. We also explored acute cardiovascular biomarkers in patients exhibiting clinical improvement.
Results:
We found that repetitive taVNS did not significantly alter heart rate, QT interval, blood pressure, or intracranial pressure (ICP). However, repetitive taVNS increased overall HRV and parasympathetic activity compared to the sham treatment. The increase in parasympathetic activity was most pronounced from 2 to 4 days after initial treatment (Cohen’s d = 0.50). Acutely, taVNS increased heart rate, blood pressure, and peripheral perfusion index without affecting the corrected QT interval, ICP, or HRV. The acute post-treatment elevation in heart rate was more pronounced in patients who experienced a decrease of more than one point in their modified Rankin Score at the time of discharge.
Conclusions:
Our study found that taVNS treatment did not induce adverse cardiovascular effects, such as bradycardia or QT prolongation, supporting its development as a safe immunomodulatory treatment approach for SAH patients. The observed acute increase in heart rate after taVNS treatment may serve as a biomarker for SAH patients who could derive greater benefit from this treatment.
Funding:
The American Association of Neurological Surgeons (ALH), The Aneurysm and AVM Foundation (ALH), The National Institutes of Health R01-EB026439, P41-EB018783, U24-NS109103, R21-NS128307 (ECL, PB), McDonnell Center for Systems Neuroscience (ECL, PB), and Fondazione Neurone (PB).
Clinical trial number:
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