Repeated, mild infections with SARS-CoV-2 can exacerbate certain brain changes associated with Alzheimer’s disease, a preclinical study shows. from Ghent University.
The results show that two consecutive mild infections with different variants of the virus in vulnerable mice can lead to fewer connections between nerve cells and more amyloid plaques.
Lien Van Hoecke and Prof. Roosmarijn Vandenbroucke conducted the study with support from Stopalzheimer. Two weeks after the second infection, they observed reduced integrity of the connections between nerve cells in the hippocampus. In mice already vulnerable to Alzheimer’s, they also found more amyloid plaques.
Conversely, no clear changes were observed in the number or activation state of microglia cells and astrocytes. Since the virus itself was not found in the brain, the researchers suspect that the changes are the result of indirect mechanisms via signals from the rest of the body.
The authors emphasize that these are preliminary results derived from animal studies. The study does not demonstrate that repeated mild COVID infections accelerate Alzheimer’s disease in humans, and no conclusions can be drawn regarding individual risk for the time being. Follow-up was limited to one month, and the impact on memory could not be investigated.
Our results show that even mild infections, which go almost unnoticed, can leave a trace in a brain that is already vulnerable.
, says Dr. Lien Van Hoecke.
In future research, the scientists want to investigate whether the brain changes persist in the long term and what the influence on memory is. They also want to unravel the interaction between the lungs and the brain, compare the effect of a single versus repeated infection, and investigate whether influenza infections have similar consequences.
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