Mitochondria-Targeting Peptide SS-31 Prevents Atherosclerosis Development in Mice | Research

The takeaway

Daily injections of the mitochondria-targeted peptide SS-31 for 12 weeks reduced atherosclerotic plaque formation in mice by suppressing oxidative stress, inflammation, and cholesterol accumulation in artery walls.

Reduced plaque area and size over 12 weeks
SS-31 peptide prevented atherosclerosis progression in ApoE knockout mice by targeting mitochondrial dysfunction, oxidative stress, and inflammation simultaneously

What the researchers found

Chronic subcutaneous administration of the mitochondria-targeted peptide SS-31 at 1 mg/kg/day and 3 mg/kg/day for 12 weeks reduced atherosclerotic plaque area and size in ApoE knockout mice fed a Western diet. SS-31 suppressed oxidative stress (reduced DHE staining, lower 8-OHDG, increased SOD activity), reduced systemic inflammation (decreased ICAM-1, MCP-1, and IL-6 levels), and inhibited cholesterol influx by downregulating CD36 and LOX-1 expression, preventing foam cell formation. Plaque composition also changed, suggesting more stable plaques.

Why it matters

Atherosclerosis is the leading cause of heart attacks and strokes, and current treatments primarily manage cholesterol levels and symptoms rather than directly targeting the oxidative stress and mitochondrial dysfunction that drive plaque formation. SS-31 (also known as elamipretide) targets the root cause — mitochondrial dysfunction — by binding cardiolipin in the inner mitochondrial membrane. This study suggests that protecting mitochondrial function could be a novel therapeutic strategy for preventing cardiovascular disease.

The numbers in context

2 doses tested: 1 mg/kg/d and 3 mg/kg/d · 12 weeks of treatment · Reduced plaque area · Decreased ICAM-1, MCP-1, IL-6 · Increased SOD activity · Downregulated CD36 and LOX-1

How the study worked

Male ApoE knockout mice (8 weeks old) were fed a Western diet and received daily subcutaneous injections of either saline (control) or SS-31 (1 mg/kg/d or 3 mg/kg/d) for 12 weeks. Atherosclerotic plaques were assessed by Oil Red O staining. Oxidative stress was measured by DHE staining and 8-OHDG immunohistochemistry. ATP levels, SOD activity, inflammatory markers (ICAM-1, MCP-1, IL-6, CRP), cholesterol transport receptors (CD36, LOX-1, ABCA1), and plaque composition (CD68, α-SMA, Masson's trichrome) were analyzed.

Who was studied

Male ApoE knockout mice (8 weeks old) fed Western diet for 12 weeks with daily SS-31 or saline injections

What this study cannot tell us

This is a mouse study using a genetic model of atherosclerosis (ApoE knockout) that does not perfectly replicate human cardiovascular disease. The ApoE knockout model develops much more aggressive atherosclerosis than typically occurs in humans. Specific quantitative results (percentage reductions in plaque area, inflammation markers) are not provided in the abstract. Long-term safety of chronic SS-31 administration was not assessed.

How to read the evidence

This is a preclinical animal study using a well-established mouse model of atherosclerosis. While the results are consistent and the mechanisms well-characterized, animal models of cardiovascular disease have limited predictive value for human outcomes, and clinical trials would be needed to confirm efficacy.

When this study was published

Published in 2017, this was an early study exploring SS-31's cardiovascular applications. Since then, elamipretide has progressed through clinical trials for other conditions (primarily heart failure and mitochondrial disease), but cardiovascular atherosclerosis trials have not yet been reported.

The bigger picture

SS-31 (elamipretide) is one of the most studied mitochondria-targeted peptides, with research spanning heart failure, kidney disease, neurodegenerative disorders, and aging. This study extends its potential to atherosclerosis prevention, reinforcing the idea that mitochondrial dysfunction is a unifying mechanism across many age-related diseases. If these results translate to humans, mitochondria-targeted peptides could represent an entirely new class of cardiovascular preventive therapy.

Questions still open

Would SS-31 be effective in reversing established atherosclerotic plaques, or only in preventing new plaque formation?
How do the anti-atherosclerotic effects of SS-31 compare to standard statin therapy, and could they be complementary?
Would the dose-response relationship observed here (1 vs. 3 mg/kg/d) translate to clinically meaningful dose optimization in humans?

Common questions

What is SS-31 and how does it target mitochondria?

SS-31 (also called elamipretide or Bendavia) is a small synthetic peptide of just four amino acids that selectively concentrates in the inner membrane of mitochondria, where it binds to a lipid called cardiolipin. This interaction stabilizes the electron transport chain, reduces the production of harmful reactive oxygen species (ROS), and improves energy production — essentially protecting the mitochondria from dysfunction.

How does mitochondrial dysfunction contribute to atherosclerosis?

Damaged mitochondria produce excess reactive oxygen species that oxidize LDL cholesterol, damage blood vessel walls, and trigger inflammation. This leads immune cells called macrophages to engulf oxidized cholesterol and become 'foam cells' that accumulate in artery walls, forming plaques. By protecting mitochondria, SS-31 interrupts this cascade at its source.

Read the original research

Chronic administration of mitochondrion-targeted peptide SS-31 prevents atherosclerotic development in ApoE knockout mice fed Western diet.

PloS one, 12(9), e0185688

View on PubMed ↗Publisher’s paper ↗

Citation

Zhang, Meng; Zhao, Hongting; Cai, Jing; Li, Huihui; Wu, Qi; Qiao, Tong; Li, Kuanyu. (2017). Chronic administration of mitochondrion-targeted peptide SS-31 prevents atherosclerotic development in ApoE knockout mice fed Western diet.. PloS one, 12(9), e0185688. https://doi.org/10.1371/journal.pone.0185688