“We may have found a specific subtype of Alzheimer’s that affects maybe 25 to 45 percent of people with the disease,” said lead author Ben Redhead of Arizona State University. This subtype of Alzheimer’s includes amyloid plaques and tau nodules, which are microscopic abnormalities in the brain used to diagnose the disease. “Also, this type of Alzheimer’s has specific biological characteristics that include viruses, antibodies, and immune cells in the brain.”
Researchers had access to various tissue samples such as intestine, vagus nerve, brain and cerebrospinal fluid of 101 people who donated their bodies. 66 of these people had Alzheimer’s disease. While Alzheimer’s is usually studied from a neurological point of view, these experimental materials gave researchers an opportunity to investigate the interaction of different body systems with Alzheimer’s.
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Researchers tracked cytomegalovirus antibodies in the donors’ intestines and then found them in the donors’ spinal fluid, brain, and even the vagus nerve. Even the virus itself was observed in the vagus nerve of these donors. When the researchers repeated the study in a separate and independent group, the same patterns were identified.
Researchers used human brain cell models to prove that the virus plays a role in Alzheimer’s disease. These models showed that the virus causes harmful proteins that contribute to the damage and death of neurons to be produced more.
It is important to note that these associations were observed only in a very small group of people with chronic intestinal infection with cytomegalovirus. Because almost everyone comes into contact with cytomegalovirus, exposure alone should not be a cause for concern.
Ben Redhead and his team are working on developing a blood test that can detect cytomegalovirus intestinal infection so that it can be treated with antiviral drugs and perhaps prevent patients from developing this type of Alzheimer’s.
The research was published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.
