Spermidine is a chemical normally found in living tissues, where it affects various biological processes. While it was recognized as important to these processes, it was not necessarily considered to be of particular interest, as it was primarily known as a precursor to other chemicals. A recent study published in Naturopathyhowever, reveals that giving spermidine to mice significantly extends their lifespan while having a cardioprotective effect.
Spermidine is a long, straight carbon chain containing three nitrogen atoms (it belongs to a class of chemicals called polyamines). Previous work has shown that spermidine treatments can extend the lifespan of flies; the hypothesis was that this could be due to increased recycling of cell material and regeneration of aging cells or perhaps by changing the energy metabolism of cells.
Similar studies had not been done in mammals, so the researchers began their study by giving young mice oral supplements of spermidine. The mice that received the oral supplement lived significantly longer than control mice. And the mice didn’t have to start young. Giving the same oral supplements to older mice caused a significant 10 percent increase in lifespan.
When the researchers looked at the heart tissue of mice that had been given spermidine from an early age, they found fewer heart problems than control mice. They also found that spermidine supplementation reduced salt-related hypertension, ventricular hypertrophy (a thickening of the muscles that decreases heart volume), and slowed the progression of heart failure. Mice given the oral supplement later in life showed a reversal of age-related heart muscle thickening.
Detailed analysis of heart tissue also showed that spermidine-supplemented mice had significantly less heart stiffness than controls and had improved diastolic properties so their hearts pumped blood more efficiently. This finding showed that oral spermidine supplementation reversed the otherwise unavoidable deterioration of heart tissue associated with age.
The tissue analysis suggested that spermidine increased levels of a chemically related amino acid and enhanced nitric oxide production. Elevated levels of these two chemicals have previously been associated with reduced cardiovascular risk.
In terms of the mechanisms at work, the authors suspect that spermidine’s protective effects are due to systemic effects, such as anti-inflammatory action and lowering blood pressure. Spermidine-induced recycling of cell material and regeneration of cardiac cells likely play an important role in the cardiac effects. Although the authors have not tested it, they suspect that this supplement may also alter cells’ energy metabolism and thus exert a protective effect.
In terms of human applications, previous epidemiological studies have shown that diets rich in spermidine are associated with better cardiovascular health. Based on the findings of this study in mice, the authors recommend an intervention study in humans as a possible next step. Since spermidine’s longevity and cardioprotective effects are evident in mice, those studies are likely already in the planning stages.
Naturopathy2016. DOI: 10.1038/nm.4222 (About DOIs).