First time scientists have observed brain tangles in an animal model through exposure to environmental toxin

January 20, 2016 – A new study published today in the science journal Proceedings of the Royal Society B indicates that chronic exposure to an environmental toxin may increase the risk of neurodegenerative illness. The cause of neurodegenerative disease remains largely unknown, and the role of environmental factors in these illnesses is poorly understood. However, scientists have long suspected a link between BMAA, a neurotoxin found in some harmful algal blooms, and neurodegenerative illness.

Brain tangles and amyloid deposits are the hallmarks of both Alzheimer’s disease and an unusual illness suffered by Chamorro villagers on the Pacific Island of Guam, whose diet is contaminated by the environmental toxin BMAA. Pacific Islanders with this unusual condition also suffer from dementia and symptoms similar to Alzheimer’s disease, motor neurone disease (MND) and Parkinson’s disease.

“Our findings show that chronic exposure to BMAA can trigger Alzheimer’s-like brain tangles and amyloid deposits,” said Paul Alan Cox, Ph.D., an ethnobotanist at the Institute for EthnoMedicine, in Wyoming, USA and lead author of the study. “As far as we are aware, this is the first time researchers have been able to successfully produce brain tangles and amyloid deposits in an animal model through exposure to an environmental toxin.”

Researchers conducted two experiments on vervets that lasted for 140 days each. The first group received fruit containing L-BMAA, the second group received fruit containing one-tenth of the regular dose of L-BMAA, the third group received fruit containing equal amounts of L-BMAA and L-serine, and the fourth group received fruit containing a placebo. After 140 days, tangles and amyloid deposits were found in the brain tissues of all of the vervets who consumed BMAA.

“This study takes a leap forward in showing causality—that BMAA causes disease,” said Deborah Mash, Ph.D., director of the University of Miami Brain Endowment Bank and co-author of the study. “The tangles and amyloid deposits produced were nearly identical to those found in the brain tissue of the Pacific Islanders who died from the Alzheimer’s-like disease.”

However, there was a significant reduction in the density of tangles in those that consumed equal amounts of L-serine.

This protective effect of L-serine was first reported by scientists in Sydney Australia in 2013 and led to clinical trials in patients with MND. “Our work showing L-serine was protective against BMAA was conducted in cells, so it’s very exciting to see it extrapolates into animals” said Dr Rachael Dunlop, a Visiting Associate at Macquarie University and member of the worldwide consortium working on this project.

Cox does not advocate patients taking L-serine at this time. "The FDA has not approved its use for the treatment of neurodegenerative illness, and much more research is needed," he said. "However, this new animal model may prove useful in evaluating other potential new Alzheimer's drugs."

The Institute has sponsored FDA-approved human clinical trials to study the effects of the naturally-occurring amino acid L-serine in people with MND, and will soon begin a Phase I human clinical trial of L-serine for patients diagnosed with mild cognitive impairment or early stage Alzheimer's disease.

The full version of the paper can be found at http://dx.doi.org/10.1098/rspb.2015.2397 once the embargo is lifted.

About the Institute for EthnoMedicine

Founded in 2004, the Institute for EthnoMedicine is a non-profit research organization dedicated to discovering new cures for neurodegenerative diseases from studies of indigenous peoples. Based in Jackson Hole, Wyo., the Institute has established a consortium of 50 scientists operating in 28 institutions across 10 countries, allowing for global collaboration through access to the latest technology and state-of-the-art laboratory facilities.

Dr Rachael Dunlop is also a member of the worldwide consortium working on this project and a Visiting Associate at the Faculty of Medicine and Health Sciences, Macquarie University. She is based in Australia and available for media interviews on 0414 184 452 rachael.dunlop@mq.edu.au  rachaeldunlop@gmail.com @DrRachie

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