A brain protein thought to cause Alzheimer’s disease could be passed to patients via contaminated surgical instruments, scientists have warned.
A study found amyloid beta in the brains of patients who had undergone neurosurgery decades ago as children or teenagers.
Years later they suffered bleeds due to a build-up of the protein in the blood vessels of their brains.
The University College London researchers behind the study said they believed the protein, which forms memory-damaging plaque, was likely to have been passed to them via contaminated instruments used in their surgery.
The authors stressed that their study was small, looking at just four people – none of whom went on to develop Alzheimer’s disease.
Experts also pointed out that modern surgical procedures provide much greater protection.
But the study adds to evidence that the protein which causes dementia may be spread in a similar way to CJD, the human form of ‘mad cow disease’, which can be caught from blood transfusions and contaminated instruments.
Professor John Collinge, of the Institute of Prion Diseases, where part of the study was carried out, said it did not show Alzheimer’s itself can be passed between people through neurosurgery.
But he added: ‘I do think we have to consider the possibility that a small proportion of Alzheimer’s cases may have occurred as a result of medical procedures many years ago. Much further research will be needed?…?even if this turns out to be the case, I can say there is no likelihood at all that anyone could catch Alzheimer’s disease from caring or living with someone who has it.’
The illness has been thought to be caused by faulty genes or ageing. But the latest study, in the journal Acta Neuropathologica, looked at the records of four people with brain bleeds caused by amyloid beta – and found they had brain surgery about 30 years ago.
In a comparison group of 50 people of similar ages from the same archives, there was no amyloid beta and only three had a recorded history of childhood neurosurgery.
The UCL team believe the protein clings to metal surgical tools. It means someone operated on with the same tools as a dementia patient could be ‘seeded’ with the protein, which can form clumps as seen in Alzheimer’s.
Author Professor Sebastian Brandner said the possibility of protein transmission, ‘while rare, should factor into reviews of sterilisation and safety practices’.
Crucially, the brains of the four people did not contain significant amounts of tau, the other protein needed to cause Alzheimer’s, and experts have urged caution in interpreting the results.
Dr James Pickett, of the Alzheimer’s Society, said: ‘At no point did any of them develop Alzheimer’s disease so there remains no evidence that Alzheimer’s is contagious.’ Dr David Reynolds, of Alzheimer’s Research UK, said the risk of amyloid beta being passed on in surgery was ‘minimal’, and that there were now ‘strict guidelines’ on sterilisation.
The Royal College of Surgeons said if further research conclusively proved the study’s findings, ‘similar guidance to that aimed at preventing the transmission of CJD could be recommended’.
© Daily Mail