Alzheimer’s disease can be caught from blood transfusions, operations and dental work, it is feared. A potentially explosive study has provided evidence that the devastating condition can, like mad cow disease, spread through “medical accidents.”
British researcher, Professor John Collinge, said we “need to rethink our view of Alzheimer’s and evaluate the risk of it being transmitted inadvertently to patients.”
One of the UK’s leading brain surgeons warned that we don’t know if the techniques used to sterilize medical instruments are effective and said that the research “must be taken seriously.”
Until now, Alzheimer’s was believed to be caused either by faulty genes or a combination of bad luck and aging.
Professor Collinge, of University College London, stumbled upon the startling link with Alzheimer’s when inspecting the brains of eight people who had died from CJD, the human form of mad cow disease. They had caught CJD after being given injections of human hormones as children to treat growth problems. He was shocked to discover a protein that is a hallmark of Alzheimer’s in the brains of seven of the eight patients. In four of them, levels of the memory-robbing amyloid beta protein were “severe.”
Writing in the prestigious journal Nature, he said that those studied were aged between 36 and 51 and such brain damage is “simply not seen” in people of that age.
With no evidence that CJD somehow triggers the build-up of the protein, Professor Collinge said the most likely answer is that it, like the CJD, had been lurking in the hormone injections. None had actually developed full-blown Alzheimer’s but they may have done if they had lived longer.
Some 1,850 British children with growth problems were treated with hormones extracted from ground up brain tissue before the procedure was banned in 1985. Around 1,500 are still alive and Professor Collinge said some of them may still develop Alzheimer’s disease. Worryingly, there is no complete record of who was treated – meaning many will have had no advance warning of the bombshell.
The study also has implications for the wider population. Professor Collinge said the similarities between the amyloid beta protein of Alzheimer’s and the prion protein that causes CJD means we must question if the two can spread in the same way. He said it is possible that contaminated medical instruments, blood transfusions and dentistry could all lead to the amyloid beta protein being passed from person to person.
The protein “sticks avidly” to metal surfaces, such as surgical instruments, and it isn’t clear if it is killed off by conventional sterilization techniques. Professor Collinge said that while transmission by blood transfusions is “possible”, surgical contamination is a bigger threat. Even dentistry is potentially of concern. The professor said, “I think one would have to consider whether certain types of dental treatment are relevant”, adding that more research would be “prudent.”
However, he stressed that he had not proved that Alzheimer’s can be passed from person to person and urged people not to panic. Professor Collinge said, “In terms of people worrying about this, it is important you understand that this relates to a very special situation, where people have been injected with extracts of human tissue. In no way does this suggest that Alzheimer’s disease is in any way contagious. You can’t catch it by living with someone with Alzheimer’s disease or by caring for someone with Alzheimer’s disease. I don’t think anyone should delay or rethink having surgery on the basis of this finding. I don’t think that any immediate action needs to be taken.”
Richard Kerr, president of the Society of British Neurological Surgeons and a consultant brain surgeon, said, “This is new information in a field of highly complex scientific enquiry that needs to be taken seriously.”