Dementia Study Is Alzheimer's Transmitted to Healthy People?

Alzheimer's disease is a particularly dreaded condition and is incurable to this day. By depositing protein, brain cells die, gradually causing them to lose their orientation, memories and consciousness. Now researchers are investigating the question of whether human-to-human transferability is possible. In the investigation of deaths from Creutzfeldt-Jakob disease they had come across appropriate evidence.

"Beta-amyloid" plays a central role in the development of Alzheimer's disease
"Can Alzheimer's be Infected by Other People?" A research team from the National Hospital for Neurology and Neurosurgery in London is currently working on this question. Thus, a "contagion" with the neurodegenerative disease may possibly be possible when used in medical procedures such as surgery. a brain operation the protein "beta-amyloid" is transmitted to healthy people. This is a specific protein that plays a key role in the development of Alzheimer's disease.

Can Alzheimer's be transmitted? One study suggests this assumption. Picture: pathdoc-fotolia

As the scientists in the journal "Nature" report, this theory arose when they examined the brains of people who had died of the rare but deadly Creutzfeldt-Jakob disease (CJD). Most patients had childhood growth hormones derived from the pituitary gland of the deceased, who were possibly contaminated with prions, according to Zane Jaunmuktane of the National Hospital for Neurology and Neurosurgery in London.

Prion deposits cause CJD-typical symptoms
The so-called "prions" are certain proteins that occur regularly in the brain in healthy form. However, a mechanism that has not yet been clarified can transform a healthy into a pathogenic prion, which then transfers to healthy proteins. Clots and deposits of protein in the brain are the result, leading to CJD-typical symptoms such as memory and concentration disorders, paralysis, tremors or epileptic seizures.

Scientists discover amyloid-ß in the blood vessels and brain substance of patients
The researchers studied eight CJD victims who died of the disease between the ages of 36 and 51 years. In addition to the signs for Creutzfeldt-Jakob, they found deposits of "beta-amyloid" proteins (amyloid-ß) in the blood vessels and the gray matter. These so-called "senile plaques" are considered to be the main cause of Alzheimer's and therefore do not usually occur in younger patients. The patients had died of other prion diseases and had received in childhood no human growth hormone, these abnormalities, however, were not, the researchers continue.

No indication of general risk of infection
The experts hypothesized that some of the hormone donors may have had Alzheimer's disease. This would allow the amyloid-ß-proteins to enter the body of the recipient and trigger the typical Alzheimer's changes in the brain. Deposits of "tau proteins" - another evidence for Alzheimer's - were, however, not discovered. However, these might still have been possible, unless the patients had previously died of CJD, the researchers continue.

Despite the new findings, there is no evidence that Alzheimer's is generally contagious, say the scientists. Nevertheless, it should be investigated whether transmission of amyloid β-proteins, e.g. by surgical instruments during surgery is possible.
"We learned a lot about decontamination through our study of CJD cases," says neuropathologist Charles Duyckaerts at the Pitié-Salpêtrière Hospital in Paris. "But this is a wake-up call for the medical community to be especially vigilant."

Commenting on the study, Mathias Jucker of the University of Tübingen and Lary Walker of Emory University in Atlanta, could also confirm the findings of the British researchers by examining residues of the administered growth hormone for amyloid-ß. In addition, it is essential to continuously monitor the surviving hormone recipients to determine if there is an increased risk of Alzheimer's disease.

"The findings of Jaunmuktane and his colleagues should encourage new research approaches in this direction. In general, they will also inspire further investigations into the mechanisms that control the formation, permeability, and toxicity of misfolded proteins in neurodegenerative diseases, "the researchers said in their commentary.

Results actuate previous findings from animal experiments
Also from the perspective of Professor dr. According to Armin Giese, the British researchers' study is conclusive and largely substantiates previous findings on the transferability of beta-amyloid proteins from animal experiments. "In my view, it is unlikely that Creutzfeldt-Jakob disease caused Alzheimer's pathology. Because in CJD patients who have not received any of these growth hormones, you see no accumulation of typical Alzheimer changes, "said the expert from the Center for Neuropathology and Prion Research at the Ludwig-Maximilians-University Munich told the news agency" dpa ".

The results would show that the clumps of the proteins are transferable under very specific circumstances. Therefore, "you [.] Now have to worry about what risks are related and how they could be prevented," said Giese. (No)