Scientists have revealed for the first time that Alzheimer’s disease was transmitted to patients given hormones taken from corpses.
Five people are believed to have developed Alzheimer’s after accidentally being treated with a human growth hormone containing dementia seeds.
The defective hormone was given to more than 1,800 short children in England between 1959 and 1995 before it was withdrawn after it was found to trigger Creutzfeldt-Jakob disease (CJD).
Now, scientists at University College London (UCL) have found that the same group responsible for cases of CJD also triggers Alzheimer’s in some patients. The youngest developed symptoms of dementia at just 38 years old.
Professor John Collinge, director of the UCL Institute of Prion Diseases and consultant neurologist at UCLH and lead author of the study, said: “We are not suggesting for a moment that you can develop Alzheimer’s disease. You can’t catch this by being a caregiver or living with a sick husband and wife.
“The patients we describe received a specific and long-standing medical treatment that involved injecting patients with material now known to be contaminated with disease-associated proteins.
“However, recognition of transmission in these rare cases should lead us to review measures to prevent accidental transmission through other medical or surgical procedures to prevent such cases from occurring in the future.”
Amyloid-beta proteins found in hormone
British scientists first came across the discovery while examining the brains of eight people who died of CJD after being injected with human growth hormone.
Unexpectedly, four of the patients had high levels of amyloid beta protein; This was a sticky buildup that formed between brain cells in Alzheimer’s patients and prevented them from communicating with each other properly.
Although none of them developed dementia, scientists say they probably would have developed dementia if they had lived longer.
Researchers later tracked down the original growth hormone stored by the Department of Health and found that it did indeed contain the misfolded amyloid-beta proteins that lead to Alzheimer’s disease.
When they injected the banned hormone into the brains of mice, the animals began to develop signs of neurodegenerative disease.
Scientists discovered that five people treated with this hormone developed symptoms of Alzheimer’s disease, even though they were between the ages of 38 and 55. None of them had a genetic risk for this condition.
First author Dr. Gargi Banerjee (UCL Institute of Prion Diseases) said: “We found that it is possible for amyloid-beta pathology to be transmitted and contribute to the development of Alzheimer’s disease.
“This transmission occurred following treatment with an obsolete form of growth hormone and often involved repeated treatments with contaminated material over several years. There is no indication that Alzheimer’s disease can be transmitted through close contact or during the provision of routine care.”
Amyloid proteins come in different types
Misfolded amyloid proteins are thought to form new “seeds” by coming together in “clumps” that grow over time and become elongated enough to break off.
Each seed continues to grow until this unbridled accumulation of amyloid in the brain begins to kill brain cells.
Dr said, general manager of research and partnerships at Alzheimer’s Research UK. Susan Kohlhaas said: “This study has revealed more information about how amyloid fragments can spread in the brain, providing more clues about how Alzheimer’s disease progresses and potential new targets for tomorrow’s treatments.”
There have been no reported cases of Alzheimer’s resulting from any other medical or surgical procedure, but experts said it was important to review precautions and possibly introduce better decontamination methods for surgical equipment.
The team also discovered that amyloid proteins are found in different species, such as viruses, and that drugs targeting the main type may allow less dominant forms to develop that cannot be treated.
Co-author Professor Jonathan Schott, honorary consultant neurologist at UCLH, said: “These findings provide potentially valuable insight into disease mechanisms and pave the way for further research that we hope will advance our understanding of the causes of more typical, late-onset Alzheimer’s disease.”
Commenting on the new research, Alzheimer’s Association’s deputy director of research and innovation, Dr. Richard Oakley said: “It is not known how common Alzheimer’s transmission was in the 1,800 people who received this treatment, and the study only looked at the records of eight people.” people.
“Patients are now given synthetic alternatives that have been approved for safety and do not pose a risk of disease transmission.”
The research was published in the journal Nature Medicine.