Summary: A large study suggests that symptomatic infection by the herpes Simplex 1 (HSV -1) virus (HSV -1) – the best known for causing cold pimples – can considerably increase the risk of developing Alzheimer’s disease. Researchers found that people with HSV-1 were 80% more likely to have Alzheimer’s disease, while those treated with antiviral drugs presented a risk of 17%.
The results align with other evidence that HSV-1 can trigger inflammation and amyloid-bêta accumulation in the brain, characteristics of Alzheimer’s pathology. Although the study is observational and cannot prove causality, it highlights the potential for antiviral therapy as a protection strategy and urges greater concentration on public health on the prevention of herpes virus.
Key facts:
- 80% higher risk: People with HSV-1 were much more likely to develop Alzheimer’s disease.
- Antiviral advantage: HSV-1 patients who took antiviral drugs presented a risk of Alzheimer’s 17% lower.
- Biological link: The HSV-1 can cause brain inflammation and amyloid accumulation, contributing to dementia.
Source: Bmj
Symptomatic infection by the virus responsible for cold buttons around the mouth – Herpes Simplex 1, or HSV -1 for short – perhaps a key role in the development of Alzheimer’s disease, suggests a major American study funded by the pharmaceutical industry published in the outdoor newspaper Open BMJ.
But treatment with antiviral treatment seems to be linked to a lower risk of this type of dementia, which suggests that the treatment to stifle the symptoms of the HSV-1 can be protective, indicate the results.
Currently, around 35.6 million people worldwide live with dementia and 7.7 million new cases are diagnosed each year, the researchers say. Alzheimer’s disease represents 60% to 80% of all dementia, total costs for its treatment reaching $ 305 billion in 2020, they add.
Various infectious agents were involved in the development of Alzheimer’s disease, and the most studied of these is the HSV-1, which affected more than two-thirds of the world around the world in 2016.
To shed light on the mentioned role of HSV-1 in Alzheimer’s disease and the potential protective effects of anti-herpetic drugs, researchers have relied on a large set of American administrative demand data (IQVIA PHARMETRICS PLUS) for the period 2006-21.
People diagnosed with Alzheimer’s disease have been paired for age, gender, geographic region, the year of entry of the database and the number of health care visits with those without history of neurological disease, which led to a total of 344,628 pairs of casing.
Almost two thirds (65%) of people with Alzheimer’s disease were women. Their average age was 73 years and they tended to have more coexisting conditions – all risk factors.
A total of 1507 (just under 0.5%), people with Alzheimer’s disease had been diagnosed with HSV-1 (0.44%) against 823 (just under 0.25%) from those of the comparison group (witness).
Unsurprisingly, the risk of Alzheimer’s disease has increased in tandem with age. But, on the whole, the probability of a diagnosis of HSV-1 was 80% higher in people with Alzheimer’s disease, after adapting to potentially influential factors.
Among the 2330 people with history of infection by HSV-1, 931 (40%) used anti-herpetic drugs after their diagnosis. And they were 17% less likely to develop Alzheimer’s disease than those who did not use these treatments.
Researchers also examined the potential role of other herpes viruses, including HSV-2, the chickenpox zona and cytomegalovirus. Infections of the HSV-2 and chicken zoster virus were also associated with an increased risk of Alzheimer’s disease.
Exactly how HSV-1 and other neurotropic viruses could increase the risk of dementia is not clear, underline the researchers.
“However, studies have shown that inflammatory brain alterations caused by HSV infection are essential in development (Alzheimer’s disease),” they explain.
“It has been reported that Aβ peptides are deposited in response to HSV infection and protect host cells by blocking viral fusion with plasma membrane, pointing HSV as a potential risk factor for (Alzheimer’s disease). Consistently, she has antimicrobial properties against various pathogens, including HSV-1, “they add.
HSV-1 DNA is also found in plates characteristic of Alzheimer’s disease, and people bearing the APOE ε4 allele, the most common genetic risk factor in the disease, are more sensitive to HSV infections, they note.
This is an observational study, and as such, no firm conclusion can be drawn on the cause and the effect. And researchers recognize that HSV -1 infections before the patient’s inclusion in the database was not known, added to which many infected people have no symptoms, while others may not ask for treatment when they do – all factors that could influence the results.
But their results comply with those of other studies. And they suggest: “Although the molecular mechanisms remain fully elucidated, these results indicate a possible role in anti -Hepetic treatment in the attenuation of the risk of dementia.”
And they conclude: “These results emphasize the consideration of the prevention of herpes viruses as a public health priority.
About this virology and news of research on Alzheimer’s disease
Author: Emma Dickinson
Source: Bmj
Contact: Emma Dickinson – BMJ
Picture: The image is credited with Neuroscience News
Original search: The results will appear in Open BMJ
