SS-31 (Elamipretide): Mitochondria-Targeted Peptide

SS-31, also known as Elamipretide and formerly as MTP-131(or Bendavia), is a synthetic tetrapeptide with the sequence D-Arg-Dmt-Lys-Phe-NH₂. It belongs to a class of mitochondria-targeted peptides (MTPs) developed by Szeto-Schiller (SS) that accumulate in mitochondria independently of membrane potential due to a combination of aromatic cationic properties and hydrophobicity.

Structure and Mitochondrial Targeting

The peptide contains 2',6'-dimethyltyrosine (Dmt), an aromatic residue that contributes to both radical-scavenging activity and selective partitioning into mitochondrial membranes. The alternating aromatic and basic residues create an amphipathic structure that associates with cardiolipin, a phospholipid found almost exclusively in the inner mitochondrial membrane. This cardiolipin binding is considered central to SS-31's mechanism of action.

Proposed Mechanisms

Published preclinical literature, including work by Szeto, Birk, and colleagues, describes several converging protective mechanisms:

• Cardiolipin stabilization: SS-31 binds to cardiolipin and prevents its peroxidation and conversion to monolysocardiolipin, preserving the structural integrity of the inner membrane and optimizing electron transport chain (ETC) complex assembly.
• Reactive oxygen species reduction: By protecting cardiolipin from oxidative damage, SS-31 reduces electron leakage and subsequent ROS generation from Complex I and III, breaking a key feedback loop in mitochondrial dysfunction.
• Cristae preservation: Studies in cardiac and skeletal muscle models report that SS-31 treatment maintains mitochondrial cristae architecture, supporting ATP synthesis and reducing apoptotic signaling through cytochrome c release prevention.
• ATP maintenance under stress: In ischemia-reperfusion, sepsis, and aging models, SS-31 has been shown to preserve cellular ATP levels and reduce biomarkers of metabolic failure.

Preclinical and Clinical Research Areas

SS-31 has been studied across a wide range of disease models and therapeutic indications:

• Cardiac ischemia-reperfusion: Animal studies demonstrate reduced infarct size and preserved left-ventricular function when administered before or during reperfusion (Szeto et al., J Pharmacol Exp Ther, 2001; Korge et al., Circ Res, 2011).
• Heart failure with preserved ejection fraction (HFpEF): Preclinical aging and metabolic stress models suggest mitochondrial dysfunction contributes to HFpEF pathophysiology, and SS-31 has shown promise in reversing diastolic dysfunction in these models (Chiao et al., Circ Heart Fail, 2016).
• Dry age-related macular degeneration (AMD): The ReCLAIM-2 trial and related studies have investigated SS-31 in geographic atrophy, with mixed results that have informed ongoing drug development strategy.
• Neurodegeneration: Models of Alzheimer's, Parkinson's, and Huntington's disease have shown that SS-31 can reduce neuronal mitochondrial dysfunction, oxidative stress, and synaptic loss in preclinical settings.
• Metabolic disease and skeletal muscle: Research in insulin resistance and aging models suggests SS-31 may restore muscle mitochondrial function and improve metabolic flexibility.

Pharmacokinetic Notes

SS-31 is a small, water-soluble peptide that does not readily cross cell membranes by passive diffusion. Instead, it appears to be taken up by cells via endocytosis or peptide-transport mechanisms and then partitions into mitochondria due to its cardiolipin affinity. Plasma half-life in humans is on the order of minutes to a few hours, but mitochondrial retention may extend the effective biological duration. It is typically studied via subcutaneous or intravenous routes in research settings.

Research Status

SS-31 (Elamipretide) has advanced to human clinical trials in cardiovascular and ocular indications, but it remains an investigational compound without FDA approval for any indication as of 2025. BioPrime offers SS-31 strictly as a reference compound for in-vitro and preclinical laboratory research conducted by qualified professionals.

References

• Szeto HH, et al. Mitochondria-targeted antioxidant peptides: A novel approach to anti-aging. AAPS J. 2014;16(3):497–501.
• Korge P, et al. Protection of cardiac mitochondria by SS-31 in ischemia-reperfusion.Circ Res. 2011;108(11):1305–1313.
• Chiao YA, et al. Renin-angiotensin system and mitochondrial dysfunction in heart failure with preserved ejection fraction. Circ Heart Fail. 2016;9(4):e002649.
• Birk AV, et al. The mitochondrial-targeted compound SS-31 re-energizes ischemic mitochondria by interacting with cardiolipin. J Am Soc Nephrol. 2013;24(8):1250–1261.