It鈥檚 not a donation that鈥檚 likely to be popular. Evidence is growing that medical procedures may have spread Alzheimer鈥檚 disease to people receiving either growth hormone or grafts during brain surgery several decades ago.
Autopsies have found signs of Alzheimer鈥檚 in the brains of five people who long-ago received dura mater surgical grafts. The dura mater is the membrane that covers the brain and spinal cord. Before synthetic membranes were invented, membrane tissue was taken from human cadavers for patching-up a patient鈥檚 membrane after neurosurgery.
The autopsies were conducted on seven people who had received such grafts, and subsequently died of the prion disease Creutzfeldt-Jakob Disease (CJD). But the autopsies revealed that five of these people, aged between 28 and 63 鈥� before the disease typically develops 鈥� also had amyloid plaques characteristic of Alzheimer鈥檚 disease in their grey matter and blood vessels.
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This finding is the second in recent months to suggest that Alzheimer鈥檚 disease can be spread via medical procedures, through the 鈥渟eeding鈥� of amyloid plaques. Last September, a different team published evidence that six people who had previously received injections of growth hormone, taken from dead donors sometime between 1958 and 1985, had developed amyloid plaques.
Lost future
Both studies looked at people who died from CJD after receiving prion-contaminated tissue or hormone taken from cadavers. This might have implied that there is a link between the diseases.
But, in their growth hormone study, of University College London and his colleagues found no evidence of amyloid protein in the brains of 116 additional people who died of CJD or other related diseases, but didn鈥檛 receive contaminated growth hormone. This suggests that the appearance of amyloid plaques isn鈥檛 simply an unexpected consequence of developing CJD.
However, some researchers doubt that these procedures could have posed an Alzheimer鈥檚 risk. Because all the patients died of CJD, it isn鈥檛 possible to know if they would have gone on to develop Alzheimer鈥檚 if they hadn鈥檛 succumbed to the prion disease.
And unless amyloid can be identified in the growth hormone or the dura mater membrane preparations that were used for these people, it will be difficult to show that they contracted their plaques from their dead donors.
According to of the German Center for Neurodegenerative Diseases in T眉bingen, evidence could come from injecting any remaining samples of the contaminated hormone into mice to see if the rodents develop Alzheimer鈥檚 plaques as well.
Collinge says these samples exist, but that such experiments take a few years.
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