Health

Moir’s experience is notable, however, because it shows that, even as one potential Alzheimer’s drug after another has failed for the last 15 years (the last such drug, Namenda, was approved in 2003), researchers with fresh approaches — and sound data to back them up — have struggled to get funded and to get studies published in top journals. Many scientists in the NIH “study sections” that evaluate grant applications, and those who vet submitted papers for journals, have so bought into the prevailing view of what causes Alzheimer’s that they resist alternative explanations, critics say.

But something had long bothered him about the “evil amyloid” dogma. The peptide is made by all vertebrates, including frogs and lizards and snakes and fish. In most species, it’s identical to humans’, suggesting that beta-amyloid evolved at least 400 million years ago. “Anything so extensively conserved over that immense span of time must play an important physiological role,” Moir said.

Moir, a native Australian, isn’t sure where he gets his anti-establishment streak, but during his undergraduate days down under he took a microbiology course from Nobel laureate-to-be Barry Marshall, who bucked orthodoxy for years by believing that a bacterial infection (H. pylori) causes ulcers. Marshall even infected himself to prove the point. “Everyone thought he was crazy,” Moir recalled. “He was crazy, but he was also right.”

If so, then the plaques it forms might be the brain’s last-ditch effort to protect itself from microbes, a sort of Spider-Man silk that binds up pathogens to keep them from damaging the brain. Maybe they save the brain from pathogens in the short term only to themselves prove toxic over the long term.

One hint of what those approaches should be comes from a 2018 study in Taiwan. It found that people with a herpes virus infection are at 2.5-fold higher risk for dementia than similar people without that infection — and that those treated with anti-herpes drugs were 92 percent less likely to develop dementia than those whose infections were left untreated.