For the first time in recorded medical history, there have been instances where Alzheimer’s disease has been transmitted from one person to another. These rare cases of transmission are believed to have been caused by a type of treatment involving growth hormones, a method that is no longer in use today.
Scientific journal Nature Medicine has published a study conducted by researchers, which details five cases in Britain where individuals developed Alzheimer’s disease several decades after they were administered growth hormone treatment during their childhood.
A notable commonality in these patients is that the onset of Alzheimer’s disease symptoms began unusually early, when they were between 38 and 55 years of age. Typically, Alzheimer’s disease is associated with the elderly and does not manifest until old age.
The specific treatment these individuals underwent involved the use of growth hormone that was extracted from the pituitary gland of deceased individuals, administered to treat short stature. In Britain, this treatment was given to just under two thousand people during the period between 1959 and 1985.
The use of this type of growth hormone was stopped in 1985, after it was discovered that some samples contained prions, which caused the neurodegenerative Creutzfeld-Jakob disease in certain individuals.
Prior to the research published in Nature Medicine, there had been instances where beta-amyloid was found in some batches of growth hormone. Beta-amyloid is a peptide that forms plaques in the brain, a common symptom of Alzheimer’s disease.
In a 2018 study, researchers demonstrated that administering growth hormones that contain beta-amyloid to mice resulted in the formation of amyloid plaques in their brains.
Similarly, it appears that this phenomenon can occur in humans as well. The researchers concluded that the five patients contracted Alzheimer’s disease due to the hormone therapy they received in their childhood, based on the uncommon age of onset and absence of genetic predisposition.
The growth hormone that these five patients received was processed in a way that did not remove prions or beta amyloids from the samples. Individuals who received growth hormone treated in different ways did not show an increased risk of contracting the disease.
The researchers highlight that no similar instances have been reported relating to any other medical treatment or procedure.
Professor John Collinge from University College London, the lead author of the study, stated that there is no evidence suggesting that Alzheimer’s disease can be transferred between individuals through daily interactions or medical treatments.
Currently, synthetic growth hormone is used in similar treatments, which eliminates the risk of disease transmission.
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“At the time, there were no alternative treatment options available and the risks were not fully understood.”
In the past, human growth hormone extracted from the pituitary glands of the deceased was also used in Finland for the treatment of growth hormone deficiency over several decades.
Assistant Chief Medical Officer of Aurora Hospital, Ilkka Sipilä, wrote in a 1994 article in Duodecim that Finland had a well-organized system for collecting and purifying this type of growth hormone, locally known as pit-GH (pituitary origin growth hormone).
Emeritus Professor of Developmental Biology at the University of Helsinki, Hannu Sariola, who also served as a chief physician of pediatric pathology, stated that he personally collected the hormone. He added, “I’m not at all surprised that Alzheimer’s disease has increased because of it. Fortunately, we have moved away from using human-derived growth hormone.”
The use of human-derived growth hormone was discontinued worldwide in 1985, which is when growth hormone produced through genetic engineering began to be used.
In Finland, there have been no reported cases of individuals contracting Creutzfeld-Jakob disease as a result of growth hormone treatment.
According to a global review of prion infections, there have been over two hundred cases worldwide, with the majority occurring in France, Great Britain, and the United States.
