Recent discovery: For the first time in the world, evidence has emerged that clinical features of Alzheimer’s disease can be transmitted from person to person. Alzheimer’s disease is the most common cause of dementia. Wei Lin, Department of Neurosurgery, PLA 101 Hospital
John Collinge and his colleagues at University College London have found signs of developing Alzheimer’s disease symptoms in the brains of deceased people with Creutzfeldt-Jakob disease (CJD). Creutzfeldt-Jakob disease can be developed through infected growth hormones.
Although interpersonal transmission is exceptional, the results of this study of eight patients with Creutzfeldt-Jakob disease raise concerns that Alzheimer’s disease may be able to be transmitted through some medical or surgical disposition. The findings were released Wednesday in the journal Nature and at the British Science Festival in Bradford.
Background
Alzheimer’s disease is commonly thought of as a degenerative disease of the nervous system. It is characterized clinically by a full spectrum of dementia manifesting as memory impairment, aphasia, dysfluency, dyscognition, impairment of visuospatial skills, executive dysfunction, and personality and behavioral changes. According to Reuters 10 reports, University College London Professor John Klinger and the Medical Research Council Prion group of experts found that the disease’s “biological seeds” may be “planted” in the brains of healthy people through improper medical procedures, in time In time, the disease may develop.
A tragic case in history
Although they have the same “character” as conventional viruses, such as filterability, infectiousness and pathogenicity, prions are not strictly speaking viruses and are much smaller than the smallest known conventional viruses, which are also commonly referred to as protein-infecting factors, virulent prions or infectious proteins, and are a class of self-replicating and infectious pathogens that do not contain nucleic acids but are composed of proteins only. They are self-replicating and infectious agents that do not contain nucleic acids but only proteins.
The incubation period of human-to-human prion diseases of medical origin caused by various medical practices can exceed 50 years. One of the famous cases is the human growth hormone treatment of 1,848 people with short stature in the United Kingdom.
In this treatment, the human growth hormone used was extracted from the pituitary gland of cadaveric origin, and no one noticed at the time that some of these pituitary gland were infected with prions. The treatment began in 1958 and was discontinued in 1985 when reports of Creutzfeldt-Jakob disease were received from the recipients of the treatment. As of 2000, 38 patients had developed Creutzfeldt-Jakob disease.
As of 2012, a total of 450 cases of medical-derived Creutzfeldt-Jakob disease have been identified worldwide, primarily from cadaveric human growth hormone therapy, with a few cases from transplants and brain surgery.
Uncovering the mechanism of “transmission”
A team of researchers from University College London conducted an autopsy study of the remains of eight patients with medical-derived Creutzfeldt-Jakob disease from the United Kingdom and performed extensive brain tissue sampling. The results of the study showed that of the eight brains sampled, in addition to all having prion disease, six exhibited some degree of beta-amyloid pathology (four of which showed extensive beta-amyloid pathology); four of them showed some degree of cerebral amyloid angiopathy.
These patients were between 35 and 51 years of age at the time of death, an age at which the above pathological features are rare, and none of them possessed the genetic variant of early-onset Alzheimer’s disease. Although no Alzheimer’s tau protein pathology was present, it is possible that the complete neuropathy of Alzheimer’s disease would have been present if these patients had survived longer.
Scientists studied 116 patients with other prion diseases and did not find any beta-amyloid pathology in the brains of patients of the same age who were not treated with human growth hormone and who were ten years older.
This study suggests that healthy individuals exposed to cadaveric human growth hormone may be at risk for developing medically-derived Alzheimer’s disease and cerebral amyloid angiopathy, as well as medically-derived Creutzfeldt-Jakob disease, as they age.
Although further research is needed to better understand the mechanisms involved, the researchers believe that it appears that, like prions, the pituitary gland, which is used to produce human growth hormone, actually contains the amyloid “seeds” that lead to the development of beta-amyloid pathology in patients.
The study also suggests that other known pathways of medical prion transmission – such as the use of surgical instruments and blood transfusions – should be studied to see if they are related to neurodegenerative diseases such as Alzheimer’s disease and cerebral amyloid angiopathy.
No need for public panic
The public, however, need not panic over the study’s findings. Researchers pointed out that although the study has scientific value, but the new findings are not conclusive and do not mean that Alzheimer’s disease must be contagious, and contact with people with Alzheimer’s disease will not transmit the disease. Sally Davis, chief medical officer of the British government, said the public need not fear brain surgery because of the study’s results, because all the research is still in the preliminary stages. As long as the procedure is safe, the patient’s health can be assured.
Eric Caron, director of Alzheimer’s Research UK, said the biggest risk factors for Alzheimer’s disease are age, genetic factors and lifestyle factors. Even if further research confirms an association between tissue contamination that once occurred and Alzheimer’s disease, the population affected would be a very limited fraction of the population.
“This does not suggest that Alzheimer’s is contagious or provide conclusive evidence that the disease can be transmitted by medical means.” A number of medical experts are also skeptical of the idea that Alzheimer’s is “contagious.” Richard Kyle, president of the British Association of Neurosurgeons, said, “With a small sample of eight people, more research is needed to get to the bottom of it.” Loverston, professor of translational neuroscience at Oxford University, said, “There’s no need to worry too much. Growth hormone therapy was discontinued long ago, and there is no evidence that other types of treatment cause patients to contract Alzheimer’s.”
“I don’t think there’s any reason to be alarmed,” says Professor Colledge, “and to assess what kind of risk there might be here — assuming the risk does exist — -a much more in-depth study is needed.” In response to questions from reporters about dental dispositions, Professor Colledge said, “There is a potential risk in dental dispositions because it touches nerve tissue, such as root canals.” But in a statement released later, he said, “Our current data do not yet implicate dental procedures.” He added, “You can’t get infected with that disease by living with or caring for someone with Alzheimer’s disease.”
China NeuroTimes composite report