New drug extends lifetime of small animals by 66 per cent
An immune system inhibitor known as rapamycin has been shown to extend the lifetime of small animals by as much as 66 per cent. “We must be very careful" before applying it to humans, warns scientists.
Aging is inevitable, with it, our body slows down, and the risk of contracting age-related diseases increase.
We already know we can postpone the effects of aging by living a healthy life, but could we achieve a similar effect with a shot of some life-prolonging drug?
The question has interested scientists for years and now it seems that they may have found a suitable substance, which has extended the life of mice and small invertebrates. It is called rapamycin and it is produced by the bacterium Streptomyces hygroscopicus.
But can this drug work in humans?
"We haven’t tested whether rapamycin has the same effect on people, but on the basis of the experiments carried out on animals we may presume that it works," says co-author Ole Vang, associate professor of molecular biology at Roskilde University, Denmark.
But there is still a long way to go before they can begin human trials. Their experiments have only been conducted on animals that are genetically distant from people.
"We need to be absolutely sure how, and under what circumstances, rapamycin has this life-prolonging effect. Then we can climb up the ladder, and eventually we’ll [look at it] in human cells," says Vang.
Experiments with copepods
Vang has experimented with copepods.
"Copepods have a short life span--about 12 to 25 days--making them ideal for aging trials. We have so far conducted two experiments, which, however, had very different outcomes," says Vang.
The first experiment showed no life-prolonging effects of rapamycin. In fact, the lifetime of the copepods reduced by eight per cent. But the second attempt resulted in an average increase in longevity of 66 per cent.
"This was because we were able to perform the experiment better [in the second trial]. During the first attempt a lot of copepods died of unnatural [causes] when we handled them," says Vang.
They used 100 copepods in both studies, stored in individual containers. Fifty per cent were fed with standard plankton, the remaining were fed with rapamycin-treated plankton. Feeding took place every fourth to fifth day, when they tallied the number of surviving copepods.
We must be very careful
Professor Kaare Christensen from the University of Southern Denmark and leader of the Danish Centre for Aging Research describes the research as “exciting” and “promising” but urges caution when it comes to how rapamycin might be used in people.
"You cannot directly transfer the results to people, but they help to give an idea of how we can investigate the phenomenon. They guide us on the way,” he says.
“However, we need to know much more about rapamycin and the mechanisms it affects before we can even consider using [it] in humans," says Christensen.
Vang agrees and points out that they need to know much more about the substance before human trials can be considered.
"The fact that rapamycin is able to stop the immune system, emphasises that we must be very careful. It’s therefore important that we continue the experiments and learn more about how we ensure the positive effects and eliminate the negative," says Vang.
Translated by: Catherine Jex
- Are invertebrates relevant models in ageing research? Focus on the effects of rapamycin on TOR, ScienceDirect (2016), doi:10.1016/j.mad.2015.12.004