In 2019, a group of researchers uncovered several genes that may be associated with an increased risk of Alzheimer’s disease. A separate study published in 2020 indicated that variations in one of these Alzheimer’s risk genes, OAS1, were associated with severe outcomes when combined with COVID19.
A new study published in the journal Brain shows that OAS1 modulates the inflammatory responses of certain cells. And other variations of OAS1 suppress this regulatory response, resulting in pro-inflammatory activity, which may explain why people who have a COVID19 mutation are at a higher risk for Alzheimer’s disease and severe forms of it.
“While there is a buildup of amyloid proteins and tangles in the brain in Alzheimer’s disease, there is also significant inflammation in the brain. This underscores the importance of the immune system in Alzheimer’s disease. ” ‘Alzheimer’s,’ explains Dervis Salih, lead author of the study. “We noticed that Alzheimer’s disease and Covid19 have several immune system problems in common.” There may be inflammatory changes in the brain in people who are severely infected with Covid19.
By focusing on the specific variant of the OAS1 gene, rs1131454, researchers discovered that it can increase a person’s baseline risk of getting Alzheimer’s disease by up to 22%. This variety is quite prevalent, with more than half of Europeans wearing it. Scientists found that looking at the molecular underpinnings of this version of OAS1 can lead to hyperactive inflammatory responses. Such responses have a role in the advancement of severe COVID19.
According to David Strain, the current study is “robust” and it fits with what we know about “cytokine storms,” which are part of the severe stages of COVID19. “We know that inflammation in brain tissue is one of the key pathways in developing Alzheimer’s disease, so it seems reasonable to conclude that any inflammatory condition would be a risk factor for negative results,” says Dr. David Strain, who was not involved in the new study.
The discovery of the genetic variant that can influence COVID is a major step forward in understanding the disease. Salih said that this discovery will allow researchers to ask questions about what exactly this variation plays in long-term COVID as well as how it might alter some of the more acute neurological symptoms associated with these diseases.
Salih says his team is still trying to understand what happens once this immune network is activated in response to an infection like Covid19. They want to know if it leads to long-term effects or vulnerability, or if understanding the brain’s immune response to Covid19, which involves the OAS1 gene, may help explain some of its neurological effects.”
Perhaps a more immediate outcome of these new results might be determining who is at high risk for severe COVID19. Salih even speculates that a simple blood test could identify early Alzheimer’s sufferers. “If we could develop a simple technique to test for these genetic variants when a person tests positive for Covid19, we could determine who is most likely to require intensive care.”
In the same way, we hope that our research can aid in the development of a blood test that could predict whether someone will get Alzheimer’s disease before symptoms appear.
Haridy, R. (2021, October 10). Missing Link Between Severe COVID-19 And Alzheimer’s Disease Discovered. New Atlas.