High levels of the protein produced by the klotho gene are associated with longevity in mammals, and recently it has also been associated with greater cognitive performance. Here is another small piece of evidence to add to all that:
Alzheimer's disease (AD) is the most frequent age-related dementia affecting 5.4 million Americans including 13 percent of people age 65 and older and more than 40 percent of people over the age of 85. In AD the cognitive decline and dementia result from the death of nerve cells that are involved in learning and memory. The amyloid protein and the excess of the neurotransmitter glutamate are partially responsible for the neuronal demise.
Nerve cells were grown in petri dishes and treated with or without Klotho for four hours. Amyloid or glutamate then were added to the dish for 24 hours. In the dishes where Klotho was added, a much higher percentage of neurons survived than in the dishes without Klotho. "Finding a neuroprotective agent that will protect nerve cells from amyloid that accumulates as a function of age in the brain is novel and of major importance. We now have evidence that if more Klotho is present in the brain, it will protect the neurons from the oxidative stress induced by amyloid and glutamate."
Klotho is a large protein that cannot penetrate the blood brain barrier so it can't be administered by mouth or injection. However in a separate study the researchers have identified small molecules that can enter the brain and increase the levels of Klotho. "We believe that increasing Klotho levels with such compounds would improve the outcome for Alzheimer's patients, and if started early enough would prevent further deterioration. This potential treatment has implications for other neurodegenerative diseases such as Parkinson's, Huntington's, ALS and brain trauma, as well."