Published: Sat, June 23, 2018
Medicine | By Tracy Klein

WIT researchers say nutrients can slow Alzheimer's

WIT researchers say nutrients can slow Alzheimer's

This concept posits that the brain reacts to a viral infection by engulfing the viruses with amyloid beta (Aβ), to prevent them from binding with host cell surfaces.

Although the study found a number of common viruses in normal aging brains, viral abundance of two key viruses - HHV 6A and 7 - was greater in brains stricken with Alzheimer's.

Researchers in the United States believe the disease may trigger an immune "cascade" which encourages the growth of amyloid plaques.

He and a team of researchers were using genetic data to look for differences between healthy brain tissue and brain tissue from people who died with Alzheimer's.

"We didn't go looking for viruses, but viruses sort of screamed out at us", said Dr. "When we built those network models, we found that the virus/host interaction contained many known Alzheimer's genes", he said. More evidence is accumulating to indicate that this loss of cognitive functioning is a mix of many different disease processes in the brain, rather than just one, such as buildup of amyloid or tau proteins.

Dudley and his colleagues stumbled across this possible viral link to Alzheimer's during an analysis meant to find ways that drugs used to treat other illnesses could be repurposed for treating the dreaded neurodegenerative disease. While a group of dedicated scientists continued to toil away at investigations correlating viral infections with Alzheimer's, the general research community began to focus on the amyloid hypothesis as the fundamental causal explanation behind the disease.

The findings were based on RNA sequencing on four brain regions in more than 600 samples of postmortem tissue from people with and without Alzheimer's.

Bryce Vissel, Professor of Neuroscience and Director, Centre for Neuroscience and Regenerative Medicine at University of Technology Sydney, said that the work is an "exceptionally important and well-executed study that presents novel evidence linking the activity of specific herpes viruses with Alzheimer's disease and offers potential new paths for disease treatment". They designed their study to map and compare biological networks underlying Alzheimer's disease. One of the primary questions is whether such pathogens play an active, causative role in the disease or enter the brain simply as opportunistic passengers, taking advantage of the neural deterioration characteristic of AD.

They found that human herpesvirus 6A and 7 were up to twice as abundant in Alzheimer's disease samples than non-Alzheimer's ones. "This is the first study to provide evidence based on multiple, large data sets that lends support to this idea". Each patient had undergone clinical evaluation to follow the course of their disease before death and neuropathological evaluation to evaluate factors, including the degree of amyloid plaque formation.

"Previous studies of viruses and Alzheimer's have always been very correlative". But "more research is needed to discover exactly what roles, if any, they play".

Alzheimer's groups have used this day to bring awareness to the disease.

Like other herpes viruses - herpes simplex, chickenpox and Epstein Barr virus - strains 6A and 7 linger dormant in the body and can reactivate later in life.

Before that can happen, though, "we need to come up with better tools to identify those with Alzheimer's who have high-risk genetics who also have virus exposure in brain", Dudley added. "This is is also consistent with the contribution of viral perturbation in driving the preclinical AD transcriptional phenotype, given that our prioritization of miR-155 was informed by findings in the preclinical AD networks". And now, not only is the viral hypothesis resurrected: "it has specific testable pathways and networks and interactions that can be explored and reconciled with the rest of the work emerging in Alzheimer's", says Dudley. "We are excited about the chance to capitalize on this approach to help in the scientific understanding, treatment, and prevention of Alzheimer's and other neurodegenerative diseases".

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