Nature discusses how the proteins that cause havoc in the brains of Alzheimer’s patients can be transmitted from person to person:
They stress that their research does not suggest that disorders such as Alzheimer’s disease are contagious, but it does raise concern that certain medical and surgical procedures pose a risk of transmitting such proteins between humans, which might lead to brain disease decades later.
“The risk may turn out to be minor — but it needs to be investigated urgently,” says John Collinge, a neurologist at University College London….
The researchers discovered extensive deposits of a protein called amyloid-beta during post-mortem studies of the brains of four people in the United Kingdom. They had been treated for short stature during childhood with growth-hormone preparations derived from the pituitary glands of thousands of donors after death.
Britain stopped the cadaver-derived growth hormone treatment in 1985 and replaced it with a treatment that uses synthetic growth hormone. But Collinge’s team was able to locate old batches of the growth-hormone preparation stored as powder for decades at room temperature in laboratories at Porton Down, a national public-health research complex in southern England.
When the researchers analysed the samples, their suspicions were confirmed: they found that some of the batches contained substantial levels of amyloid-beta and tau proteins.
That the transmissibility of the amyloid-beta could be preserved after so many decades underlines the need for caution, says [Mathias] Jucker [of the Hertie Institute for Clinical Brain Research in Tubingen, Germany]. The sticky amyloid clings tightly to materials used in surgical instruments, resisting standard decontamination methods. But Jucker also notes that, because degenerative diseases take a long time to develop, the danger of any transfer may be most relevant in the case of childhood surgery where instruments have also been used on old people.