Direct tissue transplantation can transmit the “seeds” of Alzheimer’s and related brain diseases, according to a new study. Along with other recent studies, the results could change the way people understand how prions -- rogue proteins like those that cause Mad Cow disease -- develop in the brain and potentially spread.
The scientists said that the brains of eight people showed development of Creutzfeldt-Jakob disease, caused by treatments with contaminated growth hormones from human cadavers decades before. . Six of the eight also had the amyloid buildup that is a tell-tale sign of Alzheimer’s. The scientists published their findings in Nature
, as reported by Seth Augenstein, digital reporter, in Drug Dsicovery & Development
John Hardy, a University College London (UCL) molecular neuroscientist, commented, “This is the first evidence of real-world transmission of amyloid pathology. It is potentially concerning.”
The hormone treatments were given to short people. The samples were derived from cadavers’ pituitary glands, inadvertently contaminated with prions. The treatments began in 1958 and stopped in 1985 because of reports of Creutzfeldt-Jakob. By 2000, 38 of the patients had the disease; by 2012, the number was 450 cases from the recipients of the cadaver-derived HGH and other medical procedures, such as transplants and brain surgery.
According to Mike Hanna of UCL, "This is potentially very important research. It could inform our understanding of the molecular mechanisms leading to Alzheimer's disease and will enable new programs of world-leading research in dementia.”
The extent to which prions may transmit disease is unknown. The study showed that the newly-understood Multiple System Atrophy might be spread by direct contact with re-used surgical instruments. The authors were cautious in pointing out particular dangers.
As Kurt Giles, a University of California at San Francisco researcher and one of the authors of that MSA study, explained, “You can’t kill a protein, and it can stick tightly to stainless steel, even when the surgical instrument is cleaned. As a result, we’re advocating a precautionary approach.”
Another of the authors, John Collinge, concluded, “Our findings relate to the specific circumstance of cadaver-derived human growth hormone injections, a treatment that was discontinued many years ago. It is possible our findings might be relevant to some other medical or surgical procedures, but evaluating what risk, if any, there might be requires much further research. Our current data have no bearing on dental surgery and certainly do not argue that dentistry poses a risk of Alzheimer’s disease."