Oral disease is caused by poor oral hygiene and includes periodontal or gum disease and oral cancer. While the systemic effects of oral disease are not readily apparent to an individual, more research is showing that it has a critical role in the progression of other diseases like colon cancer and heart disease. Recently, Dr. Alpdogan Kantarci and colleagues from the Forsyth Institute published a paper in the Journal of Neuroinflammation, linking gum disease to Alzheimer’s disease.
In collaboration with Boston University Kantarci and colleagues found that gum disease results in plaque formation, which is a hallmark of Alzheimer’s disease. In their report, the research team showed that gum disease can change microglial cells, immune cells in the brain. Microglial cells are responsible for brain defense against infections and intruders in the brain including amyloid plaque. These cells specifically digest amyloid plaque, so if they are altered so as not to function or die, amyloid buildup would result. Interestingly, amyloid plaque is what supports cell death in those with Alzheimer’s disease. As amyloid plaque increases, cell death increases, and the cognitive ability of the Alzheimer’s patient decreases.
The study by Kantarci and colleagues describe how plaque from gum disease can transport to the brain and change microglial cells. It was previously discovered that gum disease results in brain inflammation, which sparked interest in the whether gum disease changes microglial cells. After running a series of tests, Kantarci and colleagues found that microglial cells digest amyloid plaque, but if there is too much of it, then the microglial cells will become overstimulated and not function properly. It is as if the microglial cells “ate” too many bacteria and cannot eat anymore because there is too much in the area. Overstimulation not only neutralizes the function of microglial cells but can also kill them and allow more amyloid plaque buildup to occur.
Gum disease causes lesions to develop in the mouth and then the bacteria can enter the bloodstream through your gums and across the blood/brain barrier into the brain. Researchers then discovered that microglial cells tried to kill the invading bacteria and became overstimulated. Researchers utilized mouse models to confirm bacteria from gum disease travels to the brain and is then targeted by microglial cells resulting in altered function.
This study is critical in our understanding of the impact of oral disease on the rest of the body. For the first time, Kantarci and colleagues, demonstrated the mechanism behind oral disease which can have direct effect in the brain. This research can help scientists develop more novel and targeted strategies for gum disease and Alzheimer’s disease patients. More importantly, it can provide information to patients on how gum disease can increase the chances of getting Alzheimer’s disease. This study indicates the preventative measure individuals can take to reduce neuroinflammation and neurodegeneration indirectly lowering their chances of Alzheimer’s disease. Overall, this work shows the lasting effects of gum disease and how important it is to maintain good oral hygiene.