New research suggests that at least five cases of early-onset Alzheimer's have been linked to a medical procedure contaminated with rogue proteins.
A new study released on Monday suggests that a medical treatment** for children in the UK may lead to Alzheimer's disease in some people decades later. The study provides evidence that at least five people developed this neurodegenerative disease by receiving human growth hormone contaminated with undesirable amyloid. However, the authors point out that Alzheimer's cannot be infected from person to person by traditional means, and this particular risk of infection no longer exists today.
Beginning in the 50s of the 20th century, scientists learned how to extract human growth hormone (HGH) from the pituitary gland of cadavers. Unfortunately, this method can only provide a very small amount of the hormone at a time, which limits the availability of growth hormone for medical and research purposes. As a result, its distribution is carefully handled and is usually reserved for the most severe growth-related disorders in children.
This continued for 30 years, and more than 20,000 children worldwide received this form of growth hormone from cadavers**. But in the mid-80s of the 20th century, health in the United States and elsewhere began to receive unusual reports of people suffering from Creutzfeldt-Jakob disease (CJD), a rare but universally fatal neurodegenerative disease. These cases occurred in people much younger than typical CJD patients, and it was quickly discovered that these patients all had a history of HGH**. Within months of this discovery, the United States and other countries shut down their corpse HGH projects.
It turns out that these cases were caused by misfolded prions implanted in humans by HGH. Prions are mutated proteins that eat away at the brain by gradually converting normal prions into misfolded forms. Symptoms of prion diseases can take years or even decades to appear, which explains why it takes so long for people to discover the connection. So far, there have been about 220 cases of Creutzfeldt-Jakob disease linked to cadaver-derived growth hormone, some of which did not appear until 40 years later.
Researchers at University College London continue to track cases of potential diseases linked to growth hormone. Over time, they met patients who did not seem to have Creutzfeldt-Jakob disease but developed other neurological disorders, including Alzheimer's disease. In an article published Monday in Nature Medicine, they argued that the cases represent a rare but real form of infectious Alzheimer's disease.
This ** details 8 patients who visited the UCL National Prion Clinic. Five of them developed early-onset Alzheimer's, and one in six had mild cognitive impairment. However, none of these patients appear to have a known genetic mutation or other common factor that causes Alzheimer's disease to occur at a young age, except for a past history of HGH**.
Alzheimer's is caused by the accumulation of two misfolded proteins in the brain — amyloid and tau — that are thought to be the driving force behind both proteins. The team's past research has found that amyloid is present in the brains of people who have died from CJD-induced HGH, as well as in preserved HGH samples. In the lab, they have succeeded in exposing rats to Alzheimer's disease-like diseases after exposure to these contaminated samples.
Putting all the pieces together, the study's authors said, it was enough to show that "Alzheimer's disease should now be considered a potentially contagious disease." ”
The team's latest research shows that Alzheimer's and other neurodegenerative diseases have a lot in common with prion diseases like CJD (some scientists even believe they are actually prion diseases). For example, prion diseases are usually hereditary or spontaneously occurring, but with the exception of growth hormone**, they are rarely transmitted through contaminated beef or ritualized cannibalistic human brains. At the same time, one should not worry about developing Alzheimer's or prion disease in the same way that one worries about typical infectious bacteria, such as viruses. Now, scientists have finally learned how to synthesize growth hormone in the lab without the risk of prion or amyloid contamination. Shortly after the cadavers project was shut down, this version of HGH received regulatory approval.
It is important to emphasise that the environment in which we consider these people to be unfortunate to develop Alzheimer's is very unusual and to emphasize that there is no risk of transmission of the disease between individuals, or in routine medical care," said study author Jonathan Schott, a neurologist at University College London and chief medical officer at the UK's Alzheimer's Research Centre. "However, these findings do provide potentially valuable insights into disease mechanisms and pave the way for further research, which we hope will further our understanding of the more typical late-onset Alzheimer's disease." ”
If you like it, please pay attention to "Know the New"!