Alzheimer’s disease can develop after infection with the varicella zoster virus

Approximately 225,000 people declared in France Alzheimer’s disease Every year, after the age of 65. Although this type of dementia is common, its origin is still hotly debated among specialists. There are all the same points of consensus: amyloid plaques and clusters tau protein in nervous cells involved in the onset of symptoms typical of Alzheimer’s disease, andignition who seizes brain Patients exacerbate this Poisoning.

To explain these notes, Several hypotheses have been proposed by scientists. factors hereditary It appears to have an important role in sporadic cases of Alzheimer’s disease, which is most common, but results in downregulation of amyloid protein synthesis or interference with a microorganisms Most of the time a virus can have an underlying effect.

Experiments in the laboratory on cultured neurons

A team from Tufts University in the US presented findings that fall within the “viral hypothesis” about the origin of Alzheimer’s disease. The latter states that there is a virus sleeping In the brain – most often herpes Virus 1 or HSV-1 – “wakes up” due to factors that are still poorly defined, and leads to symptoms of Alzheimer’s disease. ” Our results point to a pathway leading to virus-induced Alzheimer’s disease VZV It causes inflammation that awakens HSV-1 in the brain Dana says cairnsthe first author ofA study published in Alzheimer’s Disease Journal.

To confirm this hypothesis, they infected Stem Cells Human neurons were labeled with viruses and looked for signs specific to Alzheimer’s disease: amyloid plaques and tau clumps, glia (proliferation glial cells in the brain) and neuritis. Their results show that VZV alone does not cause the formation of amyloid plaques and tau clumps, like HSV-1, but rather causes neuroinflammation and glia. This, according to scientists, indicates an indirect action of the VZV virus. In addition, they note that infection of cells, in which HSV-1 is dormant, by VZV reactivates the latter and causes changes typical of Alzheimer’s disease. ” It’s a double whammy from two very common and generally harmless viruses, but lab studies suggest that if additional exposure to VZV awakens dormant HSV-1, it can cause problems. Dana Kearns says.

These experiments alone are not strong enough to confirm a causal relationship between Alzheimer’s disease and VZV and HSV-1 viruses, even if the observations point in this direction. Furthermore, the various hypotheses being studied about the origin of Alzheimer’s disease are not necessarily conflicting. Viral infection could be a factor to consider in Alzheimer’s disease, among other things.