How genes may influence ageing decoded

Washington: Scientists have found that a hormone linked to the ageing process is controlled by genetics, a finding that suggests a new pathway by which genes
regulate ageing and age-related diseases.

Previous studies have found that blood levels of the hormone GDF11 decrease over time. Restoration of GDF11 reverses cardiovascular ageing in old mice and leads to muscle and brain rejuvenation, a discovery that was listed as one of the top 10 breakthroughs in science in 2014.

Scientists at the University of Georgia in US have now discovered that levels of this hormone are determined by genetics, representing another potential mechanism by which ageing is encoded in the genome.

"Finding that GDF11 levels are under genetic control is of significant interest. Since it is under genetic control, we can find the genes responsible for GDF11 levels and its changes with age," said the study's senior author Rob Pazdro,
an assistant professor at University of Georgia. The study confirmed results from previous experiments showing that GDF11 levels decrease over time and also showed that most of the depletion occurs by middle age.

In addition, the study examined the relationship between GDF11 levels and markers of ageing such as lifespan in 22 genetically diverse inbred mice strains.
The strains with the highest GDF11 levels tended to live the longest, the researchers said.

Using gene mapping, Pazdro's team then identified seven candidate genes that may determine blood GDF11 concentrations at middle age, demonstrating for the first time that GDF11 levels are highly heritable.

"Essentially, we found a missing piece of the ageing/genetics puzzle," Pazdro said. "Very generally, we've made an important step toward learning about ageing and why we age and what are the pathways that drive it," Pazdro said. The study was published in the the Journals of Gerontology Series A Biological Sciences and Medical Sciences.