Research carried out in the United Kingdom revealed for the first time the accidental transmission, through medical treatment, of the protein that causes Alzheimer's.
The finding is relevant considering that it is a disease until now only associated with old age or, to a lesser extent, with genetic inheritance.
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The authors of the study, published this Monday in the journal Nature Medicine, said that the finding highlights the need for extreme precautions. However, scientists warned that there is no reason to fear the spread of the disease.
What the new British study says about Alzheimer's
The study found that five patients treated with a contaminated growth hormone – coming from brain tissues of cadavers and out of use since 1985 – ended up developing the disease without having either age or genetic inheritance linked to it. This was contaminated with the amyloid beta protein, the accumulation of which is responsible for Alzheimer's, EFE reported.
The growth hormone c-hGH, extracted from the pituitary glands of deceased people to treat height issues, was administered to 1,848 girls and boys in the United Kingdom between 1959 and 1985.
A new finding about Alzheimer's raises some alarms (Photo: Reuters)
The suspension of its use in 1985 – and its replacement by a synthetic hormone – came from the discovery that some batches contained infectious proteins that cause Creutzfeldt-Jakob disease, a brain disorder that often leads to dementia.
How was the study carried out by British scientists on Alzheimer's
In 2017-2018, more than 30 years after this treatment stopped being used, the study authors analyzed stored samples of the growth hormone c-hGH and found that they were contaminated with the pathology associated with amyloid beta protein despite have been stored for decades.
When they administered them to mice they saw that they developed Alzheimer's. Therefore, they wondered what the evolution would have been of the girls and boys who received the treatment potentially contaminated with amyloid beta protein.
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“Our suspicion was that people exposed to that growth hormone who did not succumb to Creutzfeldt-Jakob disease and lived longer could have ended up developing Alzheimer's disease,” one of the authors explained at a press conference. , neurosurgeon John Collinge, affiliated with University College London.
What the eight cases studied reveal
The study of eight of these cases showed that five began to show symptoms of dementia between the ages of 38 and 55, and currently either have been diagnosed with Alzheimer's or meet all the diagnostic criteria for this disease.
Of the remaining three, one person met the criteria for mild cognitive impairment.
A study revealed a finding about Alzheimer's that surprised the scientific world (Photo: AP)
The unusually early age at which these patients developed symptoms suggests that they did not suffer from usual Alzheimer's associated with old age, and in all five cases the existence of the gene that makes this disease hereditary in some cases was ruled out.
”There is no indication that Alzheimer's disease can be transmitted between people during activities of daily living or routine medical care. The patients we have described received specific medical treatment that was interrupted in 1985,” Collinge emphasizes.
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However, the authors agree that the finding that Alzheimer's could be transmitted, no matter how extraordinary the circumstances, sets a precedent and should lead “to review measures to prevent accidental transmission through medical or surgical procedures, with in order to prevent these cases from occurring in the future.”
“It's not something that should worry people”
In a reaction reported by the Science Media Center platform, Tara Spiers-Jones, president of the British Society of Neuroscience, did not question the results of the study, but did emphasize that “it is not something that should worry people.”
”There is no evidence that Alzheimer's disease can be transmitted between individuals in activities of daily living, nor is there evidence to suggest that current surgical procedures carry any risk of transmission of the disease,” he added.
Along the same lines, Professor of Biochemistry at the University of Manchester Andrew Doig asked “to be cautious” and warned that, despite its solvency, the study “only takes eight patients into account.”
”There is no reason to fear the spread of the disease, since the way in which this transmission originated was stopped more than 40 years ago. The transmission of the disease from human brain to brain in this way should not occur again,” he maintained.