Supplements of spermidine, a molecule that the human body produces naturally, rejuvenate the eggs and increase fertility in old age, according to research done on mice that was presented yesterday in the journal Nature. If the same results are confirmed in people, as the authors of the research hope, spermidine could increase the expectations of having children of women who want to be mothers at an age when fertility has declined.
“Our next goal is to collaborate with a reproductive medicine center in a hospital to test the effects of spermidine on human eggs and fertility,” Bo Xiong, director of research at the University of ‘Agriculture of Nanjing (China). “We hope to help women who are trying to conceive at an advanced age.”
To study why female fertility declines with age, the researchers compared the ovaries of young and old female mice – 7 weeks old and 54 weeks old -. In this way, they have discovered that the amount of spermidine in the ovaries is reduced as the females get older.
Although spermidine was originally isolated from semen – hence the name – it is found in all organs and tissues of the human body, as well as in other species of animals, plants and fungi. It is well known among scientists who study aging, as it regulates some of the processes associated with the deterioration of organisms, such as oxidative stress, inflammation or the destruction of cells that cease to be functional. There is even a clinical trial currently underway in the UK to study whether it can improve immunity in the elderly and another in Germany to see if it can help people who have heart failure.
Bo Xiong’s team has decided to extend the studies of spermidine to fertility. In experiments with mice, it has been shown that giving spermidine supplements to older females improves the function of the ovaries, which recover spermidine levels typical of younger ages. Spermidine supplements increase the quantity of eggs produced by the ovaries and also increase their quality, which is comparable to that of eggs from young females. Consequently, they promote fertility: older females treated with these spermidine supplements have twice as many young as those that do not receive supplements.
Researchers have shown that the rejuvenating effect of spermidine on the ovaries is due to the action on mitochondria, one of the components of cells. Specifically, spermidine is key for mitochondria that do not function properly to be removed in a process called mitophagy.
Some of the research mice received spermidine by injection and others as an oral supplement. “We have seen that the effects are similar”, declares Bo Xiong. “For use in people, I think the oral route would be more convenient than injections, but more research is needed to determine its effectiveness and doses.”
“With the increasing number of people going to fertility clinics (…), it seems justified to carry out clinical trials to explore the potential of spermidine supplements”, assess Andreas Zimmermann and Frank Madeo, from the University of Graz (Austria) , in a review article in Nature Aging.
Since spermidine is found in the cells of animals, plants and mushrooms, almost all foods contain it in more or less quantity. Legumes, potatoes, soybeans, broccoli, corn and cured cheese are some of the products that have the most, according to a study by the Karolinska Institute in Stockholm. It is also sold as a parapharmacy product.
But the authors of the research warn that “an excess of spermidine is not necessarily beneficial for reproduction”. In experiments, egg maturation has been better in mice that have been treated with a medium dose than with a high dose. While waiting to establish what the appropriate dose would be in people, researchers do not advocate self-medication with spermidine to preserve fertility.
