For more than a century, scientists have known that abnormal clumps and tangles in the brain are the hallmarks of Alzheimer’s disease. But identifying the cause of that devastating damage has proven elusive, hampering efforts to come up with a cure for an affliction that robs memory from millions of people worldwide.
But what if those clumps and tangles accumulated because the brain’s garbage disposal went on the fritz? And what if a lack of sleep played some role in the breakdown of the trash-removal process?
Over the last decade, neuroscientists have been testing this provocative thesis, largely in mice. In this issue, contributor Laura Beil explains the thinking behind this theory, and why the idea that Alzheimer’s is a problem in the brain’s cleanup system is drawing such interest.
Testing the idea in humans, not surprisingly, is a lot more complicated. Answers don’t come easily. Some studies have shown more amyloid-beta plaques in the brains of people who sleep badly, while other studies have shown no such association.
And it’s hardly the only theory being tested on the cause of Alzheimer’s. In another story in this issue, our intern Leah Rosenbaum explains how other researchers stumbled upon a correlation between herpesvirus infection and Alzheimer’s disease while searching for treatment targets. Perhaps, amyloid-beta forms plaques to trap pathogens like herpesvirus, in an effort to protect the brain.
That’s all very interesting, but plenty of questions about Alzheimer’s disease remain unanswered, including a couple of chicken-and-egg doozies: Does the lack of sleep cause the brain damage, or does the brain damage cause the lack of sleep? Does herpesvirus boost Alzheimer’s risk or does Alzheimer’s somehow reactivate herpesvirus, which can sit quiet in the body for years after an infection? And since most adults have been exposed to herpesvirus, why would only some people get Alzheimer’s?
The new findings, false leads and dead ends inherent in scientific research can lead the public to get annoyed with scientists, and with science journalists. Why, readers wonder, do you people keep changing your minds? But stories of these contradictory findings and the tantalizing possibilities they raise just remind us how the process of scientific discovery works — and how science journalism lets us dive into the midst of it.
And sometimes the digressions of the scientific process can be delightful, as in life sciences writer Susan Milius’ report on the evolving explanations for a giant clam’s ability to bore its way into a coral reef. It turns out the clam’s skill set hasn’t changed; it’s science’s approach to investigating the clam’s “boring organ” that has. And yes, it’s really called that.
With Alzheimer’s, odds are that the solution won’t turn out to be as simple as getting a good night’s rest or avoiding a ubiquitous virus. But wouldn’t it be wonderful if sleep turned out to be a balm of hurt minds in more ways than we have so far imagined.