One of the hallmarks of Alzheimer’s disease (AD) is the accumulation of “tau tangles”. Tau is a protein associated with the axons of nerve cells and plays a critical role in shuttling nutrients and other essential molecules to brain cells. In Alzheimer’s patients, tau fibrils aggregate into knotted masses, resulting in nerve cell death and cognitive decline. Memory loss and personality changes are among some of the earliest signs signaling the onset of AD.
A team of Japanese researchers have developed a nasal vaccine treatment designed to prevent and treat AD progression. In a recent study published in Nature, the scientists describe promising results of the vaccine in a mouse model of AD.
The scientists used mice selectively bred to express genes that make them prone to developing dementia. A closer look at the brains of these mice show significant shrinkage of their brain tissue, or atrophy.
When vaccinated, the mice had reduced amounts of brain atrophy and reduced cognitive symptoms, behaving similarly to their healthy counterparts. Moreover, no harmful side effects were observed in the mice up to eight months after vaccine administration.
This new vaccine evokes an immune response against the tau protein, suppressing the accumulation of tau tangles. The researchers packaged the genes encoding the vaccine into Sendai virus, a harmless vector that enters the body via the mucus lining of the nasal passages.
An estimated 44 million people worldwide are living with AD, and while there are clinical strategies to improve their quality of life, there is no cure. While the vaccine shows encouraging results in an experimental model, there’s a long way to go before it will be available to patients.
“Much more research is necessary for the vaccine to be used in humans, but it is an accomplishment that can contribute to the development of a dementia cure," said Kyoto University professor, Haruhisa Inoue, a researcher involved in the study.