NMN, SS-31 and cardiac aging research

Two approaches to the aging heart in mice

The investigators compared NMN and SS-31, two interventions studied for different effects on mitochondrial-related processes. They assessed aged mouse hearts after either intervention alone and after a combination.

Cardiac function was examined using echocardiography. Additional measurements investigated metabolites and the heart's response to changes in workload. This was preclinical research, not a treatment trial in people with heart disease.

Different effects on contraction and relaxation

The study reported that SS-31 partly improved an age-associated deficit in diastolic function, the relaxation phase of the heartbeat. NMN affected an age-associated deficit in systolic function, the contraction phase. The researchers also assessed performance under a higher workload.

These distinctions matter: improvement in one cardiac measure does not imply improvement in every aspect of heart function. The combination was investigated because the two interventions were proposed to work through different mechanisms.

Metabolism during increased workload

Metabolomic analysis found changes in nicotinamide and 1-methylnicotinamide after NMN-containing interventions, consistent with altered NAD+ turnover. A substantial increase in the steady-state NAD measurement was reported for the combination.

Using magnetic-resonance spectroscopy, the researchers examined the ratio of phosphocreatine to ATP as workload changed. That ratio fell with increased workload in aged hearts but not in young hearts. Both interventions affected these energy-related dynamics.

The responses were not identical across treatment groups or measurements. The original article discusses differences between resting metabolite levels and the ability to respond to additional work. A high resting concentration should not automatically be interpreted as better physiological performance.

Why mitochondria are a focus in cardiac research

Heart muscle must repeatedly contract and relax throughout life and has a high energy demand. Mitochondrial function, oxidative stress and the regulation of NAD-related metabolism are therefore relevant research subjects.

NMN supplies a precursor for NAD+ biosynthesis, whereas SS-31 was investigated through a different mitochondrial-targeted approach. A rationale for combining them does not itself prove synergy, safety or clinical usefulness in humans.

Interpreting the findings

The experiment supports the view that distinct mitochondrial-related interventions can affect different aspects of aged mouse-heart physiology. Further investigation is required before treating those findings as a clinical strategy. They do not establish that a commercial NMN supplement repairs a human heart or substitutes for cardiovascular care.

Cited paper: SS-31 and NMN: Two paths to improve metabolism and function in aged hearts. The existing Japanese archive is the basis of this English edition.