February 15, 2018

expert reaction to amyloid beta might have been transmitted by neurosurgical instruments

Researchers examine the medical records of people who had brain bleeds caused by amyloid beta build-up in the blood vessels of the brain to investigate whether the build-up could have been transmitted by contaminated neurosurgical instruments, in a study, published in Acta Neuropathologica.

The Royal College of Surgeons and the Society of British Neurological Surgeons said:

“Any study that investigates potential links between contaminated neurosurgical instruments and the transmission of disease is to be welcomed, as the more we understand about eliminating risk, the greater the benefit for patients.

“It would perhaps be premature to draw too many conclusions from such a small sample however, if further evidence does conclusively show amyloid beta deposition, which has been linked to Alzheimer’s, may be transmissible through neurosurgical instruments, similar guidance to that aimed at preventing the transmission of Creutzfeldt-Jacob Disease (CJD/ vCJD) could be recommended.

“Following the introduction of that guidance, the previously predicted the spread of CJD/vCJD through neurosurgical procedures has not occurred.

“Guidance on patient safety and reduction of risk of transmission of Creutzfeldt–Jakob disease (CJD) via interventional procedures was published by the National Institute for Health and Care Excellence (NICE) in 2006. It advised on how best to reduce the risk of transmission of the prions, which cause CJD and vCJD via neurosurgical interventional procedures. It is currently being updated by NICE.”

Dr David Reynolds, Chief Scientific Officer at Alzheimer’s Research UK, said:

“While it is too early to draw any firm conclusions from such a small study, the finding that people with a rare amyloid-related disease all had brain operations early in life raises the possibility of amyloid having been passed from one person to another during neurosurgery.

“Any potential link will need to be explored in much larger studies, but it is important to remember that people receive vital and often life-saving brain surgery every day in the UK and any potential risk of disease from these procedures is minimal. Since the surgeries relating to these findings were carried out, strict guidelines surrounding the sterilisation and use of equipment during surgery have been introduced and continue to be evaluated.

“This study didn’t look at whether those who underwent neurosurgery in childhood went on to develop Alzheimer’s disease and there is currently no evidence that Alzheimer’s can be transmitted through brain surgery.”

Prof. Robert Howard, Professor of Old Age Psychiatry, University College London, said:

“This study provides strong, if circumstantial, evidence for an association between neurosurgery in childhood and the development in late adult life of cerebral amyloid angiopathy (CAA). CAA is a rare condition in which beta-amyloid protein (the same protein that is found in the brains of people with Alzheimer’s disease) is deposited in the walls of blood vessels in the brain and leads to a higher risk of brain haemorrhage. We already know that beta-amyloid can be “seeded” from one brain to another in animal models and the suggestion made in this paper is that neurosurgical instruments, contaminated with beta-amyloid, may have infected the brains of the people who later went on to develop CAA.

“Does this mean that Alzheimer’s disease, the most common cause of dementia that affects nearly a million people in the UK, could be infectious and spread through neurosurgical procedures or blood transfusions? I don’t think so. Firstly, this is a preliminary report and based upon only a very small sample of patients, so the association has possibly arisen by chance. We’d need to see replication of this result with larger numbers of patients before drawing conclusions. Secondly, although they share the presence of the beta-amyloid protein, CAA isn’t the same thing as Alzheimer’s disease and it is possible that the association with early neurosurgery will turn out to be restricted only to people with CAA.

“A growing number of neuroscientists believe that the similarities between rare transmissible degenerative brain diseases such as CJD and much more common conditions such as Alzheimer’s disease indicate that some as yet undiscovered infectious mechanism might be present for AD. The truth is that we just don’t know yet. If true though, this would offer exciting opportunities for prevention and treatment that are just not on the table at present.”

Dr James Pickett, Head of Research at Alzheimer’s Society, said:

“This study reports amyloid protein deposits in the blood vessels of four people decades after receiving brain surgery. However, at no point in their lives did any them develop Alzheimer’s disease so there remains no evidence that Alzheimer’s is contagious.

“While it is important to fully explore whether the amyloid protein can be transmitted in this way, without knowing more about the medical histories of these cases, we cannot draw any definite conclusions.

“Since these surgeries were conducted, and given what we know about the risk of CJD, much more stringent methods of decontaminating surgical instruments have been introduced. People who have had neuro-surgery, or have it planned in the near future, should not be unduly worried by this study.”

* ‘Evidence of amyloid-β cerebral amyloid angiopathy transmission through neurosurgery’ by Z. Jaunmuktane et al. published in Acta Neuropathologica on Thursday 15^th February 2018.

All our previous output on this subject can be seen at this weblink: http://www.sciencemediacentre.org/?s=amyloid%20beta%20human%20transmission&cat

Declared interests

None received.