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Lithium has been around since the 1800s and is commonly used to treat bipolar disorder. It’s also a metal that naturally occurs in our brains. Yet, the idea of using it to prevent or reverse Alzheimer’s disease is gaining traction, thanks in part to a report published Aug. 6 in Nature.
When researchers evaluated human brain tissue and experimented with mice, they found that declining lithium levels were linked to memory loss, says Bruce Yankner, M.D., a geneticist at Harvard Medical School. Lithium deficiency was also associated with the buildup of amyloid plaques and tau tangles — hallmarks of Alzheimer’s disease.
Then Yankner’s team gave a particular form of lithium to mice with low levels of it and saw their memory problems reverse.
Though two antiamyloid drugs are available for people with early-stage Alzheimer’s because they may slow down damage to the brain, they don’t stop it, Yankner says. Today, more than 7 million Americans live with Alzheimer’s disease.
“There’s no drug that stops the progression or restores function,” he says, adding that his research offers a “glimmer of hope.” He’s hoping to see further research in people soon.
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The lowdown on lithium
Lithium was used as a health tonic in the 1800s and was an early treatment for gout. Lithium carbonate has been the gold standard mood stabilizer for people with bipolar disorder since the 1970s. It’s been studied for cognitive problems, with mixed results.
Yankner’s human data came from an existing trial that evaluated participants who were either cognitively normal, had mild cognitive impairment (MCI) or had Alzheimer’s disease. The participants had agreed to regular testing and consented to let researchers examine their brain tissue after they died.
The researchers looked at levels of 27 metals in the brain tissue and blood. Of all the metals, lithium was the only one with low levels in the prefrontal cortex of people with MCI and Alzheimer’s disease — an area of the brain important for reasoning, planning and language.
Along with those who had Alzheimer’s disease, people with MCI — early on, even before amyloid began to form the tell-tale plaques — had lower lithium uptake, which could be due to genetic and environmental factors, Yankner says. People also may have less lithium because amyloid plaques sequester the metal in the brain.
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