Research Suggests Possible Infection Link to Alzheimer’s Disease

Recent scientific studies have started to support a concerning idea: Alzheimer’s disease might not just be a result of aging brains but could actually stem from infections. Although researchers are still piecing together how exactly this infection works, numerous studies imply that the spread of Alzheimer’s goes beyond previously held beliefs.

One significant study from 2019 pointed to gum disease as a possible bacterial offender linked to Alzheimer’s. This connection was somewhat unexpected yet intriguing.

In research conducted by Jan Potempa, a microbiologist at the University of Louisville, scientists detected the presence of Porphyromonas gingivalis, the bacteria responsible for gum disease, in the brains of patients who had passed away due to Alzheimer’s.

This wasn’t the first time a connection had been noted between gum disease and Alzheimer’s, but the researchers took it a step further. They conducted experiments on mice, where the bacteria led to brain colonization and increased production of amyloid beta (Aβ), proteins linked to Alzheimer’s.

The team, which was involved in a startup called Cortexyme, wasn’t claiming to have pinpointed a definitive cause for Alzheimer’s. Still, they did believe they were onto something important.

“While previous studies have suggested infections may influence Alzheimer’s progression, the evidence never fully convinced,” Dominy, a member of the research team, mentioned. “Now we see a compelling link between the bacteria and Alzheimer’s.”

The team found toxic enzymes, termed gingipains, in the brains of Alzheimer’s patients, which were correlated with specific disease markers like tau and ubiquitin. Even more striking was their discovery of these gingipains in the brains of individuals who had not been diagnosed with Alzheimer’s.

This finding raised significant questions. It was uncertain whether gum disease directly causes Alzheimer’s or if those dealing with dementia simply neglect their oral health.

The presence of low levels of gingipains in those without an Alzheimer’s diagnosis could indicate a potential risk for those individuals had they lived longer. The researchers suggested that the brain infection from P. gingivalis might not just be a consequence of poor dental hygiene linked to dementia but could occur long before cognitive decline.

Moreover, a compound called COR388, developed by the startup, showed promise in mouse studies for reducing the bacterial load and amyloid-beta production in established brain infections.

As research continues, there’s cautious optimism within the scientific community. Although results so far have primarily been observed in mice, there haven’t been significant advancements in Alzheimer’s treatments for over 15 years. Hence, exploring various approaches remains crucial in the fight against such diseases, according to David Reynolds from Alzheimer’s Research.

The findings were published in Science Advances.

An initial version of this article appeared in January 2019.