Scientists in Japan may be at the start of a truly monumental accomplishment: a vaccine that can slow or delay the progression of Alzheimer’s disease. In preliminary research released this week, the vaccine appeared to reduce inflammation and other important biomarkers in the brains of mice with Alzheimer’s-like illness, while also improving their awareness. More research will be needed before this vaccine can be tested in humans, however.
The experimental vaccine is being developed primarily by scientists from Juntendo University in Japan.
It’s intended to work by training the immune system to go after certain senescent cells, aging cells that no longer divide to make more of themselves, but instead stick around in the body. These cells aren’t necessarily harmful, and some play a vital role in healing and other life functions. But they’ve also been linked to a variety of age-related diseases, including Alzheimer’s. The vaccine specifically targets senescent cells that produce high levels of something called senescence-associated glycoprotein, or SAGP. Other research has suggested that people with Alzheimer’s tend to have brains filled with these cells in particular.
The team tested their vaccine on mice bred to have brains that develop the same sort of gradual destruction seen in humans with Alzheimer’s. This damage is thought to be fueled by the accumulation of a misfolded form of amyloid-beta, a protein. The mice were divided into two groups, with only one group given the actual vaccine.
In the brains of the vaccinated mice, the team found signs of reduced inflammation and fewer amyloid deposits along with lower levels of SAGP-expressing cells. These mice also seemed to behave more like typical mice compared to controls. They continued to exhibit anxiety as they aged, for instance—a trait that tends to fade in people with late-stage Alzheimer’s. They also showed more awareness of their surroundings during maze tests.
The findings were presented over the weekend at the American Heart Association’s Basic Cardiovascular Sciences Scientific Sessions 2023. That means this research hasn’t been formally peer-reviewed yet, so it should be viewed with added caution. At the same time, the team’s vaccine appears to have met an important criteria that many past attempts have failed to reach.
“Earlier studies using different vaccines to treat Alzheimer’s disease in mouse models have been successful in reducing amyloid plaque deposits and inflammatory factors, however, what makes our study different is that our SAGP vaccine also altered the behavior of these mice for the better,” said lead author Chieh-Lun Hsiao, a post-doctoral fellow in the department of cardiovascular biology and medicine at Juntendo University, in a statement released by the American Heart Association.
Of course, mice studies are only the beginning of showing that an experimental drug or vaccine can possibly work as intended. It will take further studies to validate these results and to test the vaccine’s safety in humans before large-scale trials even enter the picture.
But there have been several recent, if modest, successes in Alzheimer’s treatment as of late, and other experimental candidates—including vaccines—are already in clinical trials. With any luck, these newer and upcoming therapies might one day stop Alzheimer’s from being the incurable death sentence that it currently is today.