Researchers have found a link between chronic intestinal infections caused by a common virus and the development of Alzheimer’s disease in some people.
Most people encounter cytomegalovirus (CMV) During childhood and after the first infection, the virus remains in the body for life, usually in a dormant state.
By the time I turn 80, 9 out of 10 people They have obvious antibodies to CMV in their blood. a kind of herpes virusthe pathogen can be spread through body fluids (breast milk, saliva, blood, semen, etc.), but only when the virus is active.
In one unlucky group, the virus found a biological loophole and moved along the gut-brain axis, the “superhighway” (officially known as vagus nerve.
When the activated virus reaches the brain, it can worsen the immune system and contribute to the development of Alzheimer’s disease.
Although this is an alarming possibility, antiviral drugs could prevent some people from developing Alzheimer’s disease, especially if researchers can develop a blood test that quickly detects active CMV infection in the gut. It also means having sex.
Earlier this year, several Arizona State team members A link has been announced Relationship between a microglial subtype associated with Alzheimer’s disease, named CD83(+) due to the cell’s genetic specificity, and elevated levels of immunoglobulin G4 in the transverse colon, suggesting some type of infection.
Microglia are cells that are responsible for cleaning the entire central nervous system. They collect plaque, debris, surplus or damaged neurons and synapses. munch on Wear it whenever possible and sound the alarm if infection or damage gets out of control.
They’re here to help, but when microglia constantly fire and unleash their inflammatory arsenal without rest, they can cause the neurological damage associated with Alzheimer’s disease.
“We discovered a biologically unique sub-subsection of Alzheimer’s disease that may affect 25% to 45% of people with Alzheimer’s disease,” said lead author Ben Readhead, a biomedical scientist at Arizona State University. We think we have discovered a type.” say.
“This subtype of Alzheimer’s disease includes characteristic amyloid plaques and tau tangles (microscopic brain abnormalities used in diagnosis), and a distinct biology of viruses, antibodies, and immune cells in the brain. It is characterized by a scientific profile.
Researchers had access to various organ tissues, including colon, vagus nerve, brain, and spinal fluid, from 101 body donors, 66 of whom had Alzheimer’s disease. This helped study how the body’s systems interact with Alzheimer’s disease, which is often considered through a purely neurological lens.
They traced the presence of CMV antibodies from the donor’s intestines to the spinal fluid to the brain, and also discovered the virus itself hiding within the donor’s vagus nerve.
The same pattern emerged when the study was repeated in another independent cohort.
A human brain cell model provided further evidence of viral involvement by increasing the production of amyloid and phosphorylated tau proteins, contributing to neuronal degeneration and death.
Importantly, these associations were only found in a very small subset of patients with chronic intestinal CMV infection. Given that nearly everyone comes into contact with CMV, simply being exposed to the virus is not necessarily a cause for concern.
The readhead and team are working to develop a blood test to detect intestinal CMV infections so that they can be treated with antiviral drugs, and possibly prevent patients from developing this type of Alzheimer’s disease.
This study Alzheimer’s disease and dementia: Journal of the Alzheimer’s Association.
