Are Bacteria Causing Alzheimer’s?

Alzheimer’s disease is debilitating and difficult not only for the sufferer, but also those around them. Research into this condition has been underway for many years and, with an organ as complicated as the brain, it can be difficult to pinpoint the exact cause of this condition. Recent studies may have, however, found a link between bacteria causing gum disease and Alzheimer’s.

Alzheimer’s disease is a neurodegenerative disease for which there is no cure. The disease results in cognitive decline, and eventually death. Neurons die and break down, and high levels of amyloid and a protein called tau are known to be found in higher concentrations. As well as more conventional suspects such as a rogue protein, inflammation of nervous tissue (i.e. neuroinflammation) is also now under investigation with regards to its link to Alzheimer’s disease.neuroinflammation

It is possible that inflammation seen in Alzhiemer’s patients could be driving the disease, causing neuron degeneration. In 2017, David Emery from the University of Bristol published his findings in Frontiers in Aging NeuroscienceAlongside genetic factors which may cause you to be predisposed to neuroinflammation, it could also be a reaction to the presence of bacteria. In fact, some genes which can lead to Alzheimer’s affect the integrity of the blood vessels which usually surround and protect the brain from bacteria etc. If these vessels are damaged, it is possible that bacteria could access this delicate area and lead to inflammation. The research investigated bacteria found in the brains of Alzheimer’s patients and healthy patients. Their study found a 7-fold increase in the bacterial population when compared to healthy, aged brains. More studies are required, but it was a good indicator that bacteria could be involved in Alzheimer’s.alzheimersbacteria

In January (2019) new research emerged: a link between the bacteria behind gum disease (i.e. Porphyromonas gingivalis) and Alzheimer’s. Research was conducted by scientists across the Globe, from the US to New Zealand. The team analysed brains (donated upon death), of those who had suffered from Alzheimer’s or suspected Alzheimer’s, finding gum disease bacteria in their brains. They subsequently tested their theory on mice, and found that the bacteria could travel from the gums to the brain, and release a toxic protein (i.e. gingipain) which could destroy neurons in the brain. Other factors, which are commonly associated with Alzheimer’s, also increased as a result of bacterial presence. With this information, the researchers decided to develop a drug which would block the toxic protein and, as a result, halt brain degeneration. This drug is going into clinical trials later this year! This is not to say gum disease will lead to Alzheimer’s, but further studies are required to establish stronger links. It is however a great start, and links such as this could help in the development of better treatments.gingervitus

An earlier study, linking bacteria to Alzheimer’s, was conducted in 2014. Published in CNS & Neurological Disorders – Drug Targets, the study demonstrated a link between chronic bacterial inflammation and Alzheimer’s. They highlighted other studies which suggested that certain bacteria have the potential to initiate a cascade of events which can lead to inflammatory conditions of the central nervous system, including Alzheimer’s. Their findings culminated in the suggestion of using anti-inflammatory drugs to reduce the effects of the disease, or even prevent it in some cases. It is also known that our gut microbiome (i.e. the genes of the bacteria, fungi etc. which reside within us) affects our physical and mental health. This subject needs a whole blog post, but due to changing modern diet and lifestyle, our gut health has changed dramatically and is having more of an effect than we first realised.bacterialgoodguys

Although the brain is a very complicated organ and certainly difficult to fully understand, it is possible that bacteria are in fact contributing to the onset of  Alzheimer’s disease in some individuals. This is not to say that all Alzheimer’s disease is caused by bacteria, but it could account for a percentage which needs to be determined. If we can pinpoint which bacteria are responsible and identify them within individuals, we may be able to avoid this debilitating disease for some people. This is fascinating research and I can’t wait to see what happens next.

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