A study by the University of Louisville found a link between P. gingivalis, which causes gingivitis and is a risk factor for respiratory and coronary problems and disease. He also found that it is possible to reduce the presence of bacteria in the brain of mice.
Alzheimer's disease is one of the greatest mysteries of medicine. And while researchers are trying to find their reasons, this neurodegenerative disease, so far without treatment, is the fifth leading cause of death in the world, as the population lives longer, its frequency rising. Among the new hypotheses, one study published an alarming idea: Alzheimer's may be an infection.
Although the outlook is not new, it is the specific pathway that offers a specific type of bacteria: Porphyromonas gingivalis, gram-negative cocobacilus that causes chronic periodontitis or gingivitis.
Microbiologist Jan Potter of the University of Louisville leads a team who found that the bacteria in the brains of patients who died from Alzheimer's disease. And to test the relationship between him and the illness, they are experimenting with mice in which they find that oral infections with this bacillus increase the production of beta-amyloid, the protein that usually binds to Alzheimer's.
Stephen Dominini, co-founder of the launching Cortexyme, is involved in the investigation. The pharmaceutical company is conducting clinical trials of a drug that can prevent the proliferation of P. gingivilis toxins. Depending on its effectiveness, it can create a cure and even a vaccine against bacteria; which is not equivalent to an Alzheimer's vaccine but would provide an important way to explore therapies.
"In the past, infectious agents have been linked to the development and development of Alzheimer's disease, but evidence of a causal relationship is not convincing," said Dominini. "Now, for the first time, we have solid evidence to link the intracellular pathogen, gram-negative P. gigivalis and the pathological origin of Alzheimer's disease."
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In addition, the team found in the brain of the patients killed by this disease the toxic enzymes that bacteria secrete, called gingivalins, in correlation with two independent markers of the disease, tau protein and ubiquitin protein marker.
When they examined the brains of people who did not suffer from Alzheimer's disease before their death, scientists found lower levels of P. gingivalis, which may be a warning sign: if they lived longer, they could develop the disease.
"The identification of gingivalins in the brain of individuals with Alzheimer's and also with pathology, although not diagnosed, suggests that P. gingivalis' brain infection is not the result of poor dental health because of the onset of dementia, not a consequence of the final stages of the disease, and an early manifestation – they write in the article.
The study also looked at the drug developed by Cortexyme, called COR388, which is currently in clinical trials with Alzheimer's patients. When used in mice, it shows its ability to reduce the amount of bacteria in P. gingivalis brain infection, while reducing the production of beta-amyloid and tissue inflammation.
However, "drugs against toxic bacteria have shown benefits for mice only, so far," said David Reynolds, research director of Alzheimer Research. "But as it has been over 15 years since there is a new dementia treatment, it is important to try to choose as many approaches as possible to stop diseases such as Alzheimer's."
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The disease is usually characterized by the accumulation of amyloid and tau proteins in the brain that multiply and can be established for 10 or even 20 years before the symptoms are noticed. And while it is possible to have amyloid plaques without suffering dementia, scientists are trying to control them in seeking treatment. These proteins are thought to protect against bacteria, which would open a new path to their control: eliminate the micro-organism that causes them.
P. gingivalis not only causes gingivitis: it has also been shown to be a risk factor for inflammatory systemic diseases, pulmonary infections, myocardial infarction, arteriosclerosis and expectation of childbirth.