Researchers have found that a common, Food-and-Drug-Administration-approved sleeping pill might actually reduce the buildup of toxic proteins linked to Alzheimer’s disease. 

Today, we’re diving into the reportage of the science behind this discovery. And we’ll discuss a bit about what it could mean for the future of dementia prevention.

The Study

First thing’s first: The study we’re concerned with was written up in an article titled “Suvorexant Acutely Decreases Tau Phosphorylation and Aβ in the Human CNS,” which was published online in the March, 2023 edition of the scientific journal Annals of Neurology. And it was printed in a hard-copy version in July of the same year.

To understand the study, we first need to understand how the brain ‘cleans’ itself (quote, unquote) during sleep.  

While we sleep, our brain uses something called the “glymphatic system.” Think of it like a biological dishwasher. It flushes out metabolic waste that builds up while we’re awake.

Two of the most dangerous types of “trash” cleared out by this glymphatic system are amyloid-beta and tau proteins. 

Of course, viewers of this channel — not to mention anyone with a basic familiarity of Alzheimer’s — probably won’t fail to recognize these words.

After all, it’s these proteins that, when not cleared effectively, clump together into the notorious “plaques and tangles” that constitute the hallmarks of Alzheimer’s disease. 

This is one reason why chronic sleep deprivation is often cited as a major risk factor — alongside advanced age, of course — for cognitive decline.

Suvorexant

Enter a drug called suvorexant, known by the brand name “Belsomra.”

It’s a type of drug known as an “orexin-receptor antagonist.” Oversimplifying, orexin is a molecule in the brain that keeps us awake and alert. 

The idea is that, by blocking orexin, the drug suvorexant may encourage the brain to transition into sleep.

Researchers at Washington University School of Medicine in St. Louis, Missouri wanted to see if using this specific drug to “promote” or “enhance” sleep could help to lower the levels of the aforementioned toxic proteins.

To this end, and as scientific studies typically do, they took a group of thirty-eight healthy volunteers, aged 45 to 65, and gave them either a dose of suvorexant or a placebo before bedtime. Researchers then monitored the participants’ cerebrospinal fluid over the next 36 hours.

What Happened?

To hear them tell it, the results were striking. 

In the subset of participants who took the higher-than-usually-prescribed dose of suvorexant, levels of amyloid-beta dropped by 10 to 20 percent, compared to the placebo group. 

Even more significantly, the same group saw a drop in “phosphorylated tau” — a form of the tau protein that is particularly closely linked to brain-cell death and Alzheimer’s- disease progression.

What makes this exciting is that it wasn’t just “better sleep” clearing the brain (in some vague sense); it was a specific intervention that seemed to target the very precursors of Alzheimer’s pathology.

Caveats

However, before we get too ahead of ourselves, there are some major caveats. 

This was a very small study, and it only lasted for two nights. Therefore, researchers cannot yet say if taking this medication, long-term, will actually “prevent” dementia, or if the protein levels will stay low once the medication is stopped.

The researchers themselves prefer to refer to this as something more like a “proof-of-concept.” 

Of course, we would want to see much longer trials to decide if the observed reduction in proteins actually translates into a predictable — and reliable — reduction in cognitive decline.

That said, this study confirms that the intersection of sleep medicine and neurology is one of the most promising frontiers in medicine. And it suggests that we might eventually treat sleep not just as a lifestyle habit, but as a clinically significant tool that may help us to maintain brain health as we age.If you’re interested in the full details of the study, click for the ScienceAlert article or for the original paper. We hope you rest a little easier tonight!