New Blood Tests Detect Prion Related Diseases With High Efficiency
I see the term Prion mentioned in the news sometimes… what is it?
I would bet you are quite familiar with diseases caused by prions, they include Creutzfeldt-Jakob disease (found in humans) and Mad Cow disease. These diseases as you are likely familiar with lead to destruction of the central nervous system and brains of infected people/animals. They essentially result in the formation of actual destruction of the tissue of the brain and create actual holes (check out the image below, you can see the holes):
These diseases are caused by a protein called a prion protein. Prion proteins are common in brain cells and nervous system cells. What happens in people with these diseases is that these proteins get misfolded. Once they are misfolded two things happen, the misfolded proteins result in other prion proteins getting misfolded, and they clump together or aggregate (a phenomenon which is common in malfunctioning proteins in the brain, which you may recall from my post about Alzheimer’s disease and the aggregating beta amyloid protein).
Misfolded Prion Protein is Dangerous
Okay, so a cow has Mad Cow disease, aka it has misfolded prion protein in its brain cells (and perhaps elsewhere). Why do we care, much like other diseases the prion disease will be killed when we cook it right?
It appears that isn’t the case, the prion proteins are still an issue even after cooking. If we were to consume a cow that had Mad Cow disease we would potentially be consuming its misfolded prion proteins. You might now be thinking, well those proteins from the cow would really only effect other cow prion proteins. That is also unfortunately not true! The cow prion proteins can cause misfolding in our own prion proteins, and can lead to Mad Cow disease in humans, or as we call it, Creutzfeldt-Jakob disease.
Why is it so hard to detect?
When we do tests for diseases, we are typically looking for a foreign agent like a bacteria, or a cancer cell with a lot of extreme morphological (structural changes) and also metabolic changes. With these prion diseases we are having to identify the difference in the folded state of these prion proteins. Healthy people (or cows) already have the normal prion protein, so being able to just detect the protein itself is not sufficient. The test would have to be selective for the misfolded protein, with-out high incidence of false positives from the healthy non-misfolded protein. As you can imagine, this is not an easy feat! Even many parts of the misfolded protein are correct and not distinguishable from the incorrectly folded protein.
Okay so what about these new tests?
The newly developed blood tests correctly diagnosed 32 Creutzfeldt-Jakob disease harboring patients, correctly picking them out of 391 control patients. The tests were 100% specific for the diseased, misfolded proteins over the correctly folded wild type protein.
What is being done in these test which allows them to be so effective?
The tests were utilizing a technique called Protein misfolding cyclic amplification or PMCA to analyze blood samples. Basically the way this technique works is the researchers artificially induce conditions in the blood samples which cause the prion proteins to both be expressed in the samples, as well as are optimal for the formation of the aggregated blobs of misfolded proteins. This protocol is “cyclic” aka they repeat the necessary conditions over and over again such that if there is misfolded protein in a sample (even if it is in very low abundance) it can still be detected.
Why is this good?
Being able to effectively identify these diseases can limit their spread. Unfortunately there is currently no treatment for either Mad Cow or Creutzfeldt-Jacob disease, so limiting the exposure of people (through consumption of contaminated meat, or contaminated blood) is extremely important. Having a relatively simple and 100% effective test to identify contaminated from healthy blood samples will lead to more effectively preventing exposure. Hopefully next on the horizon will be research looking into ways to correct the misfolding, or stop the propagation in those who contract this horrible disease.
Sources:
http://www.the-scientist.com/?articles.view/articleNo/47841/title/Blood-Tests-for-Prion-Disease/
http://stm.sciencemag.org/content/8/370/370ra183
https://en.wikipedia.org/wiki/PRNP#Function
http://www.webmd.com/brain/mad-cow-disease-basics#1
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Interesting good news.
Another thing about Mad Cow disease many people are not aware of and is dangerous to their health is they think they can cook the meat really well and it will be safe.
Not true, you would have to cook the meat into an unidentifiable piece of charcoal to kill the Prion cells.
That's one reason why it's so scary and easy to get even with cooked beef.
Indeed, I said so in the post ;)
Great article. This is a good step in preventing humans from eating it. The question would be, how much would it cost to keep people safe? Mad cow is crazy because it takes so long for the prion disease to affect the human, but then it is rapidly progressive! Damn prions!
Yep, people can have it for a long time and not even know it. It's more than just eating it. Blood transfusions are another way for transmission. With a good screening technique it shouldn't be cost prohibitive to test all blood samples as a part of other regular screenings before administration.
Yep, just read it again! Another interesting thing is that there is a theory that natural melatonin (chopped up pineal gland brain tissue) from certain animals could potentially cause prion disease. Cannibalism has also lead to some crazy prion diseases. If I were to take melatonin, I would for sure not get it from a "natural source." A perfect example of when "natural" is not "better."
I would certainly prefer to take recombinant produced melatonin. It would be pure, and seemingly much cheaper to obtain then from an animal source. Do you know of any studies on that theory? I'm curious to read about it. Thanks. Also thanks for resteem. :)
No problem! I am not certain it has been correlated yet, as I have not found good evidence based data yet. It was mentioned during a medical school lecture. I found this from https://www.drugs.com/melatonin.html
Melatonin is often sold as a dietary supplement.
"The use of melatonin derived from animal pineal tissue may carry the risk of contamination or the means of transmitting viral material. The synthetic form of this medication does not carry this risk."
Time will tell I guess haha
Sorry I missed this earlier. The ability to test for Prions effectively is of the utmost importance. We still don't know for sure how many if any people are silently harbouring vCJD. Thank you for sharing.
:) thanks for giving it a read! Yeah the prion diseases are troubling, and better detection methods are imperative. This one looks very promising.