The worst disease: why France has suspended the study of prions?

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The worst disease: why France has suspended the study of prions?
The worst disease: why France has suspended the study of prions?

Imagine that you suddenly feel bad. First, there was a burning pain in the right shoulder and neck, which intensified and spread to the right side of the body. For six months, the pain persisted, followed by depression, anxiety, memory impairment and hallucinations. Scary to imagine, isn't it? However, this is exactly what happened in 2017 to an employee of one of the French laboratories named Emily Jomaine - three months after the diagnosis, the woman died. The cause of death, as it turned out, was a prion infection. Prions are a type of protein commonly found in the brain. Only these proteins can turn into an improperly folded form of themselves, which slowly turns other "normal" prions around them into outcasts. Over time, this cascading effect spreads throughout the brain and destroys it, leaving behind characteristic sponge-like holes. The most famous prion disease is Creutzfeldt-Jakob disease or mad cow disease. Mortality from it (from the moment the symptoms appear) is 100%. In this article, we will talk about why five research institutes in France at once suspended the study of these infectious agents.

Public research laboratories in France are temporarily suspending their work on prions after at least two employees are believed to have contracted a rare but ubiquitous prion brain disease.

Prions are unusual infectious agents

Prions, first described in 1982 by Dr. Stanley Prusiner of the University of California School of Medicine, are formed from proteins commonly found in the brain. When proteins turn into prions, they take on a self-propagating form and, as they accumulate, lead to brain dysfunction. Then, spreading throughout the organ, they cause irreversible damage to it.

After the discovery of prions, Prusiner hypothesized that some diseases are not caused by a virus or bacteria, but by a protein that has taken on an abnormal shape. Over time, the prion hypothesis explained why the mysterious infectious agent is resistant to ultraviolet radiation, which breaks down nucleic acids, but is susceptible to substances that destroy proteins.

The process by which this change occurs is unclear, and a lot of work is currently being done to establish the structure of the prion protein in both its normal and aberrant forms, the researchers write.

Neurodegenerative diseases caused by prions literally turn the brain into a sponge.

Scientists have recently developed a molecular model of both variants and published papers describing the structure of prion proteins (made by E. coli bacteria that have been altered using recombinant DNA techniques).

Further work using magnetic resonance imaging and X-ray crystallography should help researchers understand the key structural elements that enable prions to cause disease. It is likely that other cellular components aid them in this process, so working to understand the cellular biology of both forms of protein is vital.

Prion Diseases - What You Need to Know?

Diseases caused by prions include a number of fatal neurodegenerative diseases in humans, such as Creutzfeldt-Jakob disease (CJD), Kuru disease, and Gerstmann-Stressler-Scheinker disease (GSS).Prions also cause disease in a wide range of other animals, including bovine spongiform encephalopathy and chronic wasting disease in deer (CWD). Collectively, these diseases are called transmissible spongiform encephalopathies.

Interestingly, the cause of bottom diseases has remained a mystery to scientists for many years. For the first time, an epidemic infectious disease called kuru was identified in the 1950s in the Fore tribe of Papua New Guinea.

The transmission of the disease occurred during a ritual funeral process in which the brain of a deceased tribal member was removed from the skull, cooked, and eaten. Scientific analysis of the brains of people who died of mad cow disease or kuru showed that their brain tissue had a spongy appearance. That is, where the cells should have been, there were holes indicating encephalopathy or a decrease in the number of brain cells.

In the twenty-fourth episode of the second season of The X-Files, the townspeople contracted mad cow disease. By the way, in a very extreme way.

Previously, researchers at the US National Institutes of Health demonstrated that brain tissue samples obtained from people who died of mad cow disease or kuru could cause a similar disease in chimpanzees. These experiments apparently assumed the presence of an infectious agent.

Prions can be transmitted, possibly by ingestion and certainly by infection directly into the brain or skin and muscle tissue. Occasional, sporadic cases of prion disease occur in middle or old age, presumably because there is a very small but real possibility of prion self-transformation; the cumulative likelihood of such a transition grows over the years, the researchers note.

What happened in the French laboratory?

Prion diseases are very rare, there are no available treatments, and people usually die within months or a year of symptoms, which usually include dementia and motor dysfunction.

The first cases of mad cow disease were reported in the 1990s after eating the meat of infected animals. As for today, the first case of prion infection occurred in 2017. Lab assistant Emily Jomaine felt unwell at the end of 2017, and three months after the diagnosis (which was confirmed posthumously), she died. Emily was only 33 years old.

Emily Joman in 2010. It was then that she was exposed to prions.

While there is a possibility that Jomaine contracted the infection elsewhere, the most likely to date is that she contracted it during a laboratory accident in May 2010, when she punctured her skin with forceps used to process frozen, prion-infected brain tissue. mice genetically engineered to develop human prions.

French researchers reported the tragic incident last year. Jomene was working in a laboratory at the National Research Institute of Agriculture, Food and the Environment (INRAE) when she was suspected to be exposed to infectious agents.

Moratorium on prion studies

A three-month moratorium on further study of prions in France was imposed after INRAE ​​officials reported that another employee in one of the laboratories had also been diagnosed with CJD. The discovery of the second case was enough to force INRAE ​​and four other public research organizations to impose a three-month moratorium on prion research while investigating the circumstances of the second case.

This is how prions look like - Protein compounds with a certain configuration that can transform into pathogenic and cause neurodegenerative processes in the brain.

According to Science magazine, an employee of the laboratory, who has already retired and is still alive, contracted mad cow disease. It is unknown exactly what form of CJD is which may be a crucial clue to understanding the origin of her disease.

Most cases of mad cow disease are sporadic and appear to occur without any specific cause. It is known that in some cases this disease is inherited, that is, it occurs in people with certain hereditary mutations.

Most often, the disease is associated with transmission from another animal, usually a cow. These forms differ markedly from sporadic ones, with sporadic cases occurring more often in older people, while Creutzfeldt-Jakob disease tends to affect younger patients.

In theory, however, all forms of CJD can be transmitted by close enough contact with an infected brain substance (another prion disease, kuru, is notorious for cannibalism).

Brain scan of a patient with Creutzfeldt-Jakob disease.

Friends and colleagues of Jomene have called for increased laboratory safety measures during prion research.

Laboratory infections are known to occur with many pathogens, but exposure to the prions that cause Creutzfeldt-Jakob disease is unusually risky because there are no vaccines or treatments. And while most infections are detected within days or weeks, the average incubation period for CJD is around 10 years.

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