Single Hormone Tied to Longevity and Intelligence

A hormone that has long been associated with an increased life-span has now been linked to increased intelligence. The gene expression associated with increased levels of this hormone may one day provide means to treat cognitive decline, researchers suggest.

According to a study published in Cell Reports, raising levels of the hormone klotho may be the secret to longer and smarter lives.

Researchers from the Gladstone Institute of Neurological Disease and the University of California in San Francisco initially set out to determine if the klotho hormone - appropriately named after the Fate from Greek mythology who spins the thread of life - could delay cognitive decline in aging people.

The researchers theorized that because klotho had been proven to slightly reduce the effects of cell degradation in human bodies, it would stand to reason that the hormone has similar effects on brain cells, potentially protecting them from the adverse effects advancing age has on a person's memory and thinking power.

However, according to the study, initial observations showed that people who express a genetic variant that encourages production of the klotho hormone still lost memory and cognitive powers at the same rate as aging patients who had low levels of the hormone.

Interestingly, the team did find that nearly all the participants who has the klotho-production gene, called KL-VS, appeared to have stronger initial cognition, despite their regular rate of decline.

To further investigate this phenomenon, the researchers compared mice with the KL-VS gene verses mice who did not express the gene. Without fail, mice who had the gene - and thus, higher klotho levels - preformed better in cognitive testing. When studying the brains of these mice, the researchers found that brains with high klotho levels appeared to have stronger synaptic connection, suggesting that the hormone strengthens communication pathways between brain cells.

It remains to be seen if the KL-VS gene variant and its resulting elevate klotho levels affects the human brain in the exact same way, but the researchers are encouraged by their findings.

Study author Dena Dubal of the University of California told All Things Considered that while her team's initial hypothesis did not prove correct, the klotho study still led to a potentially new route for the treatment of brain degradation. While the hormone cannot halt brain degradation entirely, elevating klotho levels as a patient ages may help strengthen a weakening mind.

The study was published in Cell Reports on May 8.