Fruit flies live 16% longer than average when given low doses of the mood stabiliser lithium, according to a study published in the journal Cell Reports.

How lithium stabilises mood is poorly understood but when the scientists investigated how it prolongs the lives of flies, they discovered a new drug target that could slow ageing - a molecule called glycogen synthase kinase-3 (GSK-3).

The team found that lithium delays ageing by blocking GSK-3 and activating another molecule called NRF-2, which is found in worms, flies and mammals (including humans) and is important for defending cells against damage. According to the scientists, GSK-3 could be a target for drugs to control ageing.

The study, published today in Cell Reports, shows that male and female flies live longer than average when given low doses of lithium during adulthood or later in life, regardless of their genetic make-up. At low doses, few adverse effects were seen in the flies as they continued to feed normally and produce healthy offspring.

Different doses of lithium chloride were given to 160 adult flies to measure the effect on lifespan. Higher doses reduced lifespan but lower doses prolonged life by an average of 16% and maximum of 18% compared to a control group given sodium chloride.

The benefits of lithium were also seen when it was used as a transient and one-off treatment. Flies that received a one-off dose near the end of their lives lived a maximum of 13% longer and young flies given low doses of lithium chloride for 15 days before switching to a control for the remainder of their lives also lived longer.

"We studied the responses of thousands of flies in different conditions to monitor the effects of lithium and how it extends life. We found low doses not only prolong life but also shield the body from stress and block fat production for flies on a high sugar diet. Low doses also protect against the harmful effects of higher, toxic doses of lithium and other substances such as the pesticide paraquat," said co-author. 

http://www.ucl.ac.uk/news/news-articles/0416/070416-fruit-flies-live-longer-on-lithium