I recently found out about the so-called prion diseases, which are incurable and fatal diseases that affect (a euphemism, the real word is destroy) the CNS and cause a rapid deterioration of mental and physical abilities.
There are many prion diseases, the two most famous are probably the mad cow disease (non-human mammals), and the Creutzfeldt–Jakob disease (CJD) (for human mammals). Both are 100% fatal, and *no one* is known to have survived longer than 2.5 years after a CJD diagnosis. That’s the kind of stuff you wouldn’t wish on your worst enemy.
Why are these diseases so deadly? I read that it has to do with abnormal proteins but that was way over my head.
EDIT : I have another question, can prion diseases be rightly called the most dangerous diseases known to man ?
Thanks;
In: Biology
Prions are misfolded proteins. They cause other proteins they come in contact with to misfold as well. They are kind of like zombies in that regard. A misfolded protein is no longer able to do its job in the body. Once too many misfolded, you get sick and eventually break down and die.
The only way to destroy them is with extreme heat, which naturally can’t be done while the person is alive.as it is just a protein the immune system has no way of dealing with them. It doesn’t recognize them as a problem.
Prion is a protein in your brain that’s doing messy things. It’s really small and there are many other proteins in the brain, so it’s extremely hard to get out without butchering the brain.
They’re also quite rare, so there isn’t too much research done on curing them, other than preventing you getting it in the first place, such as inspection of beef and other meat
A prion disease is an incorrect fold in your brain proteins (needed for your brain to survive) – it also unfortunately a more ‘optimal’ fold in a lot of cases, so it ‘corrects’ the other proteins in your brain to be folded wrong and clump together with it. Each wrong protein also has the potential to cause a chain reaction and make thousands more wrong proteins, which makes it impossible to cure even if you can remove one clump.
Normal prion proteins’ function in the brain is not nailed down, but it essentially protects neurons from damage such as oxidative stress and excess ions like copper. It’s not really a single protein, but a complex of proteins and a couple other anchoring molecules. Since there are many molecules involved, if it is damaged and folds the wrong way these broken, unstable molecules will bond to anything, preventing the complex from returning to it’s original structure. The instability of the broken molecule affects those around it, as there is a delicate balance to maintaining chemical bonds within the brain. Without prions, neurons are susceptible to apoptosis, or programmed cell death, and synaptic degeneration, resulting in cells not being able to communicate. It loses it’s delicate connections and dies from the inside out.
So proteins are almost always folded so that they can do stuff. When something happens like genetics or a disease, then you get these misfolded proteins. Sometimes, these are corrected. But when they are not, you get these prions.
Prion are misfolded proteins that misfold other proteins, which causes a sort of domino effect until you have so many misfolded proteins accumulating in the brain and that causes damage.
Now, your body doesn’t easily recognize these prions as foreign as easily as it would for bacteria, viruses, or fungi because these proteins are not foreign! They’re just mistakes of your body’s own proteins.
The reason why there is such a high fatality rate is because we have no current drugs to “kill” these misfolded proteins without killing your normal proteins. However, there is some research [some research](https://www.science.org/content/article/can-new-drugs-stop-deadly-set-brain-eating-diseases) into drugs that turn down expression of these proteins at the source. They prevent prions from being made. Hope this helps.
Have you ever seen one of those videos of popsicle’s sticks intertwined and then the guy releases one of the sticks and everything starts collapsing like a domino effect? It’s the same thing. Once one of the proteins got the wrong folding then all others starts misfolding as well. You can’t reverse it because it would need to correct all proteins in the person’s body at the same time, which is absolutely impossible with the knowledge we have to this day
They are misfolded proteins that cause other proteins to be misfolded. This is very dangerous to the brain because it disrupts the white and grey matter structures of the brain, slowly destroying it and eventually causing death. You can’t destroy them like bacteria or viruses because it’s just a bunch of structural molecules, not a living thing which can have its metabolism disrupted (bacteria) or be tagged by antibodies (viruses). Now they’re not invincible, but you need either a very strong denaturing agent or extremely high temperatures. Suffice to say that kills the person infected.
Our bodies use proteins as building materials and for various functions in the body. They are crucial to our ability to live, and are fairly durable. A prion is a malformed protein that causes other proteins to become similarly malformed, spreading the problem and stopping their normal function.
For an analogy imagine you have an army (your body) fighting invaders (bacteria, etc). Your army men can attack the invaders (your immune system fighting back), and you can also use things like poison gas against them (antibiotics, etc). The poison gas you pick can be ones your army has gas masks against while the invaders do not.
But now imagine that your army encounters bolts laying around on the ground. These are standard machine or structural bolts, but they are flawed and brittle. Even worse when those bolts get near other bolts they make them brittle as well! A tank drives out into a field and comes back with a few brittle bolts. More of its bolts become brittle until the tank breaks, but it also spread the brittle bolt condition to other tanks. And to the workshop’s structural frame! This shop also services transport trucks which also use bolts.
The workshop collapses from bad bolts, and the base barracks. Some stretches of the perimeter fence also fall over. The transport trucks visit supply depots and contaminate the warehouses. From there more transport trucks spread the brittle bolts to the factories themselves, where production lines begin to break down. Your army is collapsing, it is doomed.
How do you fight this? Your army guys don’t recognize bolts as an enemy, and they can’t shoot them even if they could. Your poisons do nothing against the bolts, they aren’t even alive. Anything you can use that would destroy the bolts would also destroy whatever they are in and things around it as well. Once they are in your infrastructure the only way to get rid of them is to destroy it all, and if that infrastructure is critical? You are out of luck.
Ending the analogy, the only prions we know of infect the neurological system of the body. Once prions are in your brain there is nothing to be done, you are inevitably doomed. Luckily getting exposed to brain or nerve tissue is somewhat difficult.
Now to give you nightmares: I don’t know of any reason that other kinds of prions are not possible. Maybe a prion could exist that affects proteins in the skin, spreading via contact. Maybe you could have lung tissue impacted by prions spread by coughing. The proteins could remain dangerous indefinitely, only being deactivated by extreme temperatures exceeding 1000 Celsius. Cleaning chemicals and alcohol hand sanitizer does nothing. Infection is invariably fatal.
Sleep well.
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because this type of disease attacks a fundamental process for biology: protein formation and whether the host ‘s immune system is able ot pick up onthis problem or not is entirely left to chance.
the other major issue is that this is a pervasive problem: one misfolfed protrein will inevitably causes other to also misfold and once you hit a critical mass the cell is gonna die…but likely not before reproducing.
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