How two common viruses can trigger Alzheimer’s

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Are two common viruses responsible for the onset of Alzheimer’s? Photo credit: Bloomberg Creative/Getty Images.
  • A new study has found that two of the most common viruses most people carry may interact to cause Alzheimer’s disease.
  • Vaccines against one of the viruses may reduce the risk of developing Alzheimer’s disease.
  • Research shows that other common viruses can trigger the development of the debilitating condition.

A combination of extremely common viruses may be the underlying cause of Alzheimer’s disease (AD), according to a study by researchers at Tufts University in Medford, Massachusetts.

The virus responsible for chicken pox and shingles can activate the dormant herpes virus, which is strongly associated with AD, in its active state.

Varicella zoster virus (VZV) is the virus that causes chickenpox or chicken pox – in childhood and zoster can occur – swelling — later in life.

Corresponding author of the study, Tufts Prof. David Kaplan reported Medical news today that “[m]More than 95% of adults have had chickenpox in childhood and adolescence. The virus then remains in the body.

Co-author Dr. This was reported by Ruth Itzaki, a professor at the University of Oxford and an honorary professor at the University of Manchester MNT “A decline in the immune system with young age and immunosuppression” are factors that can cause VZV to reemerge as a tumor in adults.

Before the new study, “VZV was linked to AD, but the link was unclear and the mechanisms were not understood,” said Dr. Itzhaki.

Research shows that when VZV becomes active as a tumor, it reactivates the dormant one Herpes simplex type 1 (HSV-1). In 2021, Dr. Yitzhak published an important study body of research demonstrating an association between activated HSV-1 and AD.

HSV-1 is also very common, with 50% to 80% of American adults carrying the virus. Although the oral or genital form of VZV is active, it can cause painful blisters at the site of infection.

Dr. Itzaki noted:

“What is now known is that infectious diseases in general increase the risk of AD, and our results explain this for shingles. We are now investigating whether there are other infections. If so, then this explains the main danger of infectious diseases.

“If we change the paradigms,” said Prof. Kaplan, “by focusing more on preventive strategies to treat these microbial species before they cause this devastation, we may be able to do a better job of preventing this disease.”

research will appear Journal of Alzheimer’s Disease.

“Thirty years of evidence from my lab, and many others since, show that HSV-1 is the primary cause of AD, but the disease is clearly multifactorial,” says Dr. Itzaki told us.

In his speech, prof. As Kaplan notes, “a number of factors have been reported to reactivate HSV-1 from a latent state, including stress and disease states.” Dr. Itzaki added “stress, immunosuppression, UV light and menstruation” as possible triggers.

Dr. Tariq Pascoal, assistant professor of psychiatry and neurology at the University of Pittsburgh School of Medicine, who was not involved in the study, commented on the findings.

“This study adds to the evidence that HSV-1 may cause neuroinflammation associated with an increased risk of Alzheimer’s disease,” he said.

“Interestingly,” he added, “this study suggests that this occurs independently of amyloid and tau deposits, which may support the notion that there are independent pathways of neuroinflammation leading to AD, or that the presence of inflammation may reduce brain reserve and make patients more susceptible to the development of AD.”

“If the latter is true,” said the doctor. Pascoal, “we can imagine that different viruses increase the risk of AD, including COVID-19.”

There is evidence that both HSV-1 and VZV can reactivate after COVID-19, the study authors noted.

This was reported by Professor Kaplan MNT he believes his research “also demonstrates how 3D tissue modeling can be used to elucidate such interactions and synergies in relatively rapid ways.” Most AD research uses animal models.

To test the effect of active VZV on inactive HSV-1, Prof. Kaplan and his colleagues created brain-like spheres inside six-millimeter-wide donut-shaped sponges made of silk protein and collagen.

Neural stem cells – some of which became functional neurons and some became brain glial cells – were delivered to the sponges.

After injecting VZV into the brain tissue, the researchers found that when the neurons became infected, there was no reason for the development of the amyloid plaques or tau protein clumps characteristic of AD. More importantly, neuronal activity remained intact.

However, when they injected VZV into neurons with dormant HSV-1, HSV-1 reactivated, amyloid and tau protein growth increased, and the electrical signals from neurons began to slow down, similar to AD.

Researchers have put a lot of effort into developing HSV-1 vaccines, but there is no successful vaccine yet. Some have suggested that mRNA vaccines may be a more fruitful way forward.

Dr. “I think there’s reason to be hopeful that we’ve learned a lot about mRNA vaccines during the COVID pandemic in a short period of time,” Pascoal said.

“I’m optimistic that in the coming years we’ll have effective mRNA-based vaccines for a variety of targets using the knowledge gained with COVID-19,” he told us.

Dr. Heather M. Snyder, the Alzheimer’s Association’s vice president for medical and scientific communications and was not involved in the study, but said with some caution.

“Any potential therapy needs to be evaluated in multiple, rigorous human studies. There are several studies underway using antiviral drugs, including one funded by the Alzheimer’s Association through our Part the Cloud initiative,” he noted.

Meanwhile, while there is no vaccine for HSV-1, there are vaccines against herpes. It supports the idea that stopping VZV can help people avoid AD previous studyincluding Dr. Itzhakin’s own.

As noted, getting a booster shot does indeed reduce the risk of AD.

At the same time, Dr. Snyder said, “As we age, research shows that physical activity, a balanced diet, and keeping our brains active and active are good for our bodies and our brains. Learn more about reducing your risk of cognitive decline and dementia at the Alzheimer’s Association website.

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