Scientists have cautioned that shingles may increase the risk of Alzheimer’s disease.
According to a study performed by Oxford University, the infection can trigger a chain reaction in the brain that is associated with dementia.
This is accomplished by reawakening a different, typically harmless herpes virus that has been dormant in our systems since childhood.
This results in a ‘dramatic’ accumulation of plaque and inflammation in the brain, two characteristics of Alzheimer’s disease.
Varicella occurs when the body is initially exposed to the varicella-zoster virus (VZV), typically in childhood. Shingles are caused by secondary infections.
Researchers created a three-dimensional brain using brain cells generated in the lab to examine the effects of VZV on the brain.
They discovered that it did not directly cause Alzheimer’s disease hallmark changes.
However, it reactivated the cold sore-producing simplex virus (HSV-1), creating a fast accumulation of damaging proteins.
The author of the study, Dana Cairns of Tufts University in Massachusetts, stated, “It’s a one-two punch of two very common and typically harmless viruses.”
‘However, laboratory studies indicate that if a new exposure to VZV reawakens dormant HSV-1, it could pose problems.’
HSV-1 is generally dormant in the human body, and there is substantial evidence linking it to dementia.
According to previous studies, elderly individuals with high levels of the virus in the brain are at an increased risk for Alzheimer’s.
Professor Ruth Itzhaki from the University of Manchester collaborated on the current study with researchers from the Institute of Population Ageing at the University of Oxford and Tufts University.
Researchers recreated brain-like habitats in 6-millimeter-wide sponges comprised of silk protein and collagen in the shape of donuts.
They populated the sponges with stem cells that differentiated into neurons and were able to transmit impulses, exactly as neurons do in the brain.
The results demonstrated that VZV can infect neurons in the brain, although this does not necessarily result in the creation of plaque and cell death.
Virus-infected neurons retained their usual functionality.
However, if the cells also included HSV-1, there was a significant rise in tau and beta-amyloid proteins, which are significantly associated with dementia.
In addition, the neural transmissions began to slow down.
Professor Itzhaki stated, “This remarkable result appears to demonstrate that viruses such as VZV can produce a rise in brain inflammation in humans, which can reactivate dormant HSV-1.”
The brain damage caused by repeated infections over a lifetime might eventually result in Alzheimer’s disease or dementia.
‘This would imply that vaccines could play a larger role than just protecting against a single illness, as they could indirectly provide some protection against Alzheimer’s through lowering infections.’
The study was published in Alzheimer’s Disease Journal.
Shingles can be quite painful and seem to strike older persons more frequently.
Approximately one in five individuals who have had chickenpox get zoster, with the majority being in their seventies.
Researchers also warn that obesity, smoking, alcohol consumption, and head trauma may raise the risk of Alzheimer’s disease by compromising the immune system and reactivating dormant HSV1 in the brain.
More than 900,000 individuals already living with dementia in the United Kingdom, with that number expected to increase to 1.6 million by 2040.
Alzheimer’s is the most prevalent kind of dementia.
The illness affects an estimated 5.8 million Americans, the majority of whom are over the age of 65.
