Stanford researchers are making progress on treating the cognitive problems of Down syndrome, according to a new study published today in Biological Psychiatry. The study showed that an existing FDA-approved medication could improve cognitive function in a mouse model of Down syndrome.
The work is important because, in recent years, improved treatments for the physical problems associated with Down syndrome have extended patients' lives. But the cognitive problems of Down syndrome have been difficult to treat, meaning that children with the genetic disorder still fall behind their peers in school and adults still develop Alzheimer's-type pathology in their brains by age 40.
From our press release about the new study:
The drug, an asthma medication called formoterol, strengthened nerve connections in the hippocampus, a brain center used for spatial navigation, paying attention and forming new memories, the study said. It also improved contextual learning, in which the brain integrates spatial and sensory information.
Both hippocampal function and contextual learning, which are impaired in Down syndrome, depend on the brain having a good supply of the neurotransmitter norepinephrine. This neurotransmitter sends its signal via several types of receptors on the neurons, including a group called beta-2 adrenergic receptors.
"This study provides the initial proof-of-concept that targeting beta-2 adrenergic receptors for treatment of cognitive dysfunction in Down syndrome could be an effective strategy," said Ahmad Salehi, MD, PhD, the study's senior author and a clinical associate professor of psychiatry and behavioral sciences.
A Los Angeles Times story about the study explains an important caveat to the findings and describes what's next for the research:
Nonetheless, the experiment was just a “proof of concept,” Salehi cautioned. The dose was far above the quantity deemed safe for asthma use in humans. Before even considering human trials, researchers will have to reduce that dosage and see if its positive effects remain. Still, the path to prescription could be shorter because of the drug’s approval for other uses. Drug companies also could be inspired by the findings to create even better long-acting compounds that influence norepinepherine, Salehi said.
“Making a drug in a lab and taking it into a treatment for people, these days, is going to cost $1 billion and at least something like 10 years,” Salehi said. “Being approved doesn’t mean it’s a great drug, but at least it’s been studied much more thoroughly compared with other drugs that we have in the lab.”
Previously: Does Down syndrome need a “cure”?, More on the debate over “curing” Down syndrome and Moving toward a Down syndrome drug