Baku, February 1, AZERTAC
The controversial theory that the "seeds" of Alzheimer's disease may have been transmitted between patients during surgical procedures involving the use of donated human tissue has been supported by the discovery of new evidence, according to The Independent.
Scientists have found a link between patients who received nerve-tissue grafts several decades ago and the presence of a protein in the brain that is normally seen in the earliest stages of Alzheimer's disease.
The study supports findings published last September suggesting that people who had been injected with human growth hormone when they were children were harbouring the same seeds of Alzheimer's disease at the time of their death several decades later.
The latest study was carried out on the stored brain samples of eight patients who had undergone tissue grafts in Austria and Switzerland but who had died from another brain disease, Creutzfeldt-Jakob disease (CJD), which is now known to have been transmitted during the operation involving nerve tissue taken from human cadavers.
The retrospective analysis of the eight patients found that seven of them, who had died at ages ranging from 28 to 63, had clumps of protein in their brain called amyloid-beta (A-beta). This is seen in the early stages of Alzheimer's but is highly unusual in such a relatively young age group.
Five of the seven patients had also suffered visible damage to the vital blood vessels of the brain caused by the build-up of A-beta protein – an observation that is also highly unusual in such a young age group.
A control group of 21 brains from patients who had died of sporadic CJD indicated that the results were not the result of CJD but likely to be caused by the tissue graft.
Other possible causes have yet to be conclusively eliminated. But scientists suspect that the seeds of the A-beta protein may have been transmitted to the patients at the time they had a surgical graft of the dura mater, a membrane that covers the brain and spinal cord – which at that time came from cadavers, before the practice was stopped in the 1980s.
The findings support the view that it may be possible for certain medical procedures to inadvertently transmit the seeds of Alzheimer's disease from one person to another – although there is no suggestion that Alzheimer's can be "caught" by touching or caring for someone with the degenerative brain disease.