Fight Aging!

In aging research inadvertent calorie restriction has been the usual confounding factor in life span studies carried out with short-lived animals. If the treatment under study happened to cause animals to eat less then there was indeed an extension of life, but due to reduced calorie intake rather than the treatment. The calorie restriction response is large compared to the results of most interventions under study, and many studies were contaminated because there was no control for calorie intake. There are any number of other ways in which life span studies can be compromised, however. For example solvents extend life in nematodes, which is a problem for all experiments using them, a list that includes a range of genetic studies of longevity carried out prior to the solvent discovery. Here researchers find a similar problem in fly studies, wherein a part of the methodology of genetic engineering is shown to extend life:

Some studies on the genetic roots of aging will need a second look after the discovery that a common lab chemical can extend the life span of female fruit flies by 68 percent. For years, scientists have engineered fruit flies whose genes can be turned on and off by a synthetic hormone, allowing detailed studies of the effects of single genes on life span. Many of the genes have close relatives in humans. Unfortunately, the hormone used to perform the studies turns out to be anything but neutral.

Researchers grew suspicious of the hormone that they and others were using to activate the genes - mifepristone, a synthetic chemical known to terminate pregnancy in humans. Many studies have shown that reproduction shortens lifespan in flies and other organisms. Researchers wondered if the hormone they were using could be affecting reproduction in flies, and in turn their life span. They discovered that flies exposed to the hormone laid only half the usual amount of eggs - and lived 68 percent longer, from a median age of 56 to 94 days. The mifepristone had little or no effect on the life expectancy of female flies that had not mated, which had an even better overall survival rate and maximum lifespan.

"This opens up a new line of inquiry for longevity studies, and identifies candidate genes and mechanisms for regulating the trade-off between reproduction and lifespan that may be shared with humans. It does, however, mean that our earlier longevity studies that relied on mifepristone as a gene switch will need to be reevaluated."

Link: http://www.eurekalert.org/pub_releases/2015-02/uosc-nf020415.php