MSA is a prion disease?


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MSA is a prion disease?

Postby Robin » Thu Sep 03, 2015 6:01 pm

Though this post is of most interest to the very few MSA members here, I'm posting this more out of general interest ... Also, I want to note upfront that this ground-breaking research is made possible through generous people donating their brains.

There was big news this week (starting Monday, 8-31-15) about MSA research.

Prions are "infectious proteins" that spread in the brain like a virus or bacteria. The Nobel Prize-winning discoverer of prions is Stanley Prusiner at UCSF. The most well-known human prion disease is Creutzfeldt-Jakob Disease (CJD), a very rare disorder involving PrP prions. The most well-known animal prion disease is mad cow disease. Suggestions have been made over the last several years that perhaps Alzheimer's or Parkinson's is caused by prions.

Two weeks ago and today (in two separate papers), Dr. Prusiner and a team of researchers reported that "multiple system atrophy (MSA) is caused by a...human prion composed of the alpha-synuclein protein."

Here's a link to NPR's All Things Considered's discussion of this research on Monday:

Scientists Discover New Disease Caused By Prion Protein
www.npr.org/2015/08/31/436377464/scient ... on-protein

The 3.5-minute radio segment notes that MSA may be transmissible from person to person! Probably that should say "from brain to brain" as spinal tissue or fluid must be involved.

Here's a related part of the UCSF press release on the public health aspect of this research:

"The discovery that alpha-synuclein prions can transmit MSA raises a public health concern about treatments and research that involve contact with brain tissue from neurodegeneration patients, because standard disinfection techniques that kill microbes do not eliminate the PrP prions that cause CJD. Whether the same challenges hold for alpha-synuclein prions in MSA remains to be determined. ... The authors write that clinicians and researchers should adopt much more stringent safety protocols when dealing with tissue from patients with MSA and other neurodegenerative diseases, many of which they believe may also be caused by prions. For instance, MSA is frequently initially diagnosed as Parkinson's disease, which is often treated with deep-brain stimulation. The disease could potentially be transmitted to other patients if deep-brain stimulation equipment is reused. ... [The] researchers stress that there is no apparent risk of infection by MSA prions outside of specialized medical or research settings."

This makes me wonder if some people who had PD and got deep brain stimulation (DBS) surgery, actually acquired MSA from the surgical instruments used during DBS. That's alarming to consider.

This excerpt from the UCSF press release explains how the discovery was made:

"The new work has its origins in experiments conducted in Prusiner's lab in 2013, showing that samples of brain tissue from two human MSA patients were able to transmit the disease to a mouse model for Parkinson’s disease, expressing a mutant human alpha-synuclein gene. To confirm this finding, Prusiner and colleagues expanded this experiment to include tissue samples from a dozen more MSA victims from tissue banks on three continents... The results were the same: When exposed to human MSA tissue, the mice developed neurodegeneration. In addition, the team found that the brains of infected mice contained abnormally high levels of insoluble human alpha-synuclein, and that infected mouse brain tissue could itself spread the disease to other mice."

Note that this research was made possible only through the generosity of those who donated their brains!

You can read the full UCSF press release here:

www.ucsf.edu/news/2015/08/131416/new-ty ... generation

And you can read the abstract for the Prusiner article here:

www.pnas.org/content/early/2015/08/27/1 ... 2.abstract

Both Lewy Body Dementia and Parkinson's Disease are also disorders of alpha-synuclein protein. If I'm understanding the full Prusiner paper accurately, researchers also tried to get human Parkinson's Disease tissue from six brain donors to transmit PD to transgenic mice. None of the mice developed Parkinson's Disease. It would seem that the "strain" (or variant) of alpha-synuclein that causes PD is different from the transmissable strain that causes MSA.

(Actually, four patients were diagnosed with "Lewy body disease" or Parkinson's Disease. And two patients were diagnosed with "diffuse Lewy bodies," which is Lewy body dementia.)

Perhaps PSP and CBD researchers will want to investigate if these disorders are transmissable as well. They are disorders of tau, not alpha-synuclein.

Robin
Robin
 
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