Fusobacterium nucleatum (F. nucleatum) is a common type of bacteria that proliferates in periodontal disease. It affects the gums and jawbone, and if untreated results in unstable teeth and tooth loss. In recent years, F. nucleatum has been linked to conditions ranging from colorectal cancer to premature delivery of babies.
Now new research from the US suggests a link between F. nucleatum and Alzheimer’s disease.
“In this study, our lab is the first to find that Fusobacterium nucleatum can generate systemic inflammation and even infiltrate nervous system tissues and exacerbate the signs and symptoms of Alzheimer’s disease,” said Dr Jake Jinkun Chen at Tufts University, Massachussets.
F. nucleatum can also generate severe generalised inflammation, which is a symptom of many chronic diseases including type 2 diabetes and Alzheimer’s disease.
Dr Chen and his colleagues—who have published their findings in Frontiers in Aging Neuroscience—believe that by targeting F. nucleatum, they can slow the spread and progression of periodontal disease and Alzheimer’s.
The latest research, done in mice, shows that F. nucleatum results in an abnormal proliferation of microglial cells, which are immune cells in the brain that normally remove damaged neurons and infections and help maintain the overall health of the central nervous system. This over-supply of microglial cells also created an increased inflammatory response, the researchers found. Chronic inflammation or infection is believed to be a key determinant in the cognitive decline that occurs as Alzheimer’s disease progresses.
“Our studies show that F. nucleatum can reduce the memory and thinking skills in mice through certain signal pathways. This is a warning sign to researchers and clinicians alike,” Dr Chen said.
While the new research does not show that F. nucleatum-related periodontal disease leads directly to Alzheimer’s disease, the new study suggests that periodontal disease caused by F. nucleatum and left untreated or poorly treated could exacerbate symptoms of Alzheimer’s disease. Conversely, treating periodontal disease effectively in those who have early-stage Alzheimer’s could potentially slow Alzheimer’s progression.
