You'll have to make sure your doctor uses this information to prevent your 33% chance of getting dementia.
http://www.ninds.nih.gov/news_and_events/news_articles/pressrelease_brain_diseases_07032013.htm
It only takes one bad apple to spoil the bunch, and the same may be
true of certain proteins in the brain. Studies have suggested that just
one rogue protein (in this case, a protein that is misfolded or shaped
the wrong way) can act as a seed, leading to the misfolding of nearby
proteins. According to an NIH-funded study, various forms of these seeds
— originating from the same protein — may lead to different patterns of
misfolding that result in neurological disorders with unique sets of
symptoms.
“This study has important implications for Parkinson’s
disease and other neurodegenerative disorders,” said National Institute
of Neurological Disorders and Stroke (NINDS) Director Story Landis,
Ph.D. “We know that among patients with Parkinson’s disease, there are
variations in the way that the disorder affects the brains. This
exciting new research provides a potential explanation for why those
differences occur.”
An example of such a protein is
alpha-synuclein, which can accumulate in brain cells, causing
synucleinopathies, multiple system atrophy, Parkinson’s disease,
Parkinson’s disease with dementia (PDD), and dementia with Lewy bodies
(DLB). In addition, misfolded proteins other than alpha-synuclein
sometimes aggregate, or accumulate, in the same brains. For example, tau
protein collects into aggregates called tangles, which are the hallmark
of Alzheimer’s disease and are often found in PDD and DLB brains.
Findings from this study raise the possibility that different structural
shapes, or strains, of alpha-synuclein may contribute to the
co-occurrence of synuclein and tau accumulations in PDD or DLB.
In
the new study, published in Cell, Jing L. Guo, Ph.D., and her
colleagues from the University of Pennsylvania Perelman School of
Medicine, Philadelphia, wanted to see if different preparations of
synthetic alpha-synuclein fibrils would behave differently in neurons
that were in a petri dish as well as in mouse brains. They discovered
two strains of alpha-synuclein with distinct seeding activity in
cultured neurons: while one strain (strain A) resulted in accumulation
of alpha-synuclein alone, the other strain (strain B) resulted in
accumulations of both alpha-synuclein and tau.
The researchers
also injected strain A or strain B into the brains of mice engineered to
make large amounts of human tau, and then monitored the formation of
alpha-synuclein and tau aggregates at various time points. Mice that
received injections of synuclein strain B showed more accumulation of
tau — earlier and across more brain regions — compared to mice that
received strain A.
The researchers also examined the brains of
five patients who had PDD, some of whom also had Alzheimer’s. In this
small sample, there was evidence of two different structural forms of
alpha-synuclein, one in PDD brains and a distinctly different one in
PDD/Alzheimer’s brains, supporting the existence of disease-specific
strains of the protein in human diseases.
“We are just starting to
do work with human tissues,” said Virginia M.Y. Lee, Ph.D., senior
author of the study. “We are planning to look at the brains of patients
who had Parkinson’s disease, PDD, or DLB to see if there are differences
in the distribution of alpha-synuclein strains.”
Although the two
strains used in this study were created in test tubes, the authors
noted that in human brains, where the environment is much more
complicated, the chances of forming additional disease-related
alpha-synuclein strains may be greater.
“These different strains
not only can convert normal alpha-synuclein into pathological
alpha-synuclein within one cell, they also can morph into new strains as
they pass from cell to cell, acquiring the ability to serve as a
template to damage both normal alpha-synuclein and other proteins,” said
Dr. Lee. “So certain strains, but not all strains, can act as templates
to influence the development of other pathologies, such as tau
tangles.”
She commented, “We are just beginning to understand some
of these strains and there may be many others. We hope to find a way to
identify strains that are relevant to human disease.”
This study
was supported by grants from NINDS (NS53488) and the National Institute
on Aging (AG17586). Additional funding was provided by the Marian S.
Ware Alzheimer Program, Philadelphia, PA; the Dr. Arthur Peck Fund,
Philadelphia, PA; The Jeff and Anne Keefer Fund, Philadelphia, PA; and
the Parkinson Council, Bala Cynwyd, PA.
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