Many things have not yet been confirmed about Alzheimer's disease. One of the most intriguing aspects is whether the disease can be transmitted from one person to another. A new study solidifies this claim once again, reigniting fears that the disease may be spread through surgery.

Within a period of four months, two expert groups have already performed autopsies suggesting that Alzheimer's may be transmitted via medical or surgical treatments. Scientists, however, iterates that nothing is conclusive yet.

The latest study was performed by researchers from the University Hospital Zurich and Medical University Vienna. The scientists studied brains of seven patients aged 26-63 years old, all of whom died of neurological disease called iatrogenic Creutzfeldt-Jakob disease (CJD).

The patients were diagnosed of iCJD years after they received a growth hormone from a human cadaver.

Human cadaveric hormone has been recognized to be a source of Alzheimer-type amyloid-β (Aβ). Hence, the researchers analyzed the rate of Aβ pathology among those who received brain grafts.

The findings show that Aβ was deposited in the brain vessels of five out of seven brains studied.

The first study published in September 2015 also had similar results, with four out of eight found to have amyloid plaques after surgically receiving contaminated growth hormones.

"Our results are all consistent," says co-author John Collinge.

Both studies did not firmly conclude that Alzheimer's can indeed be transmitted through normal contact with patients. They also point out that synthetic cadavers and synthetic growth hormones are not being used anymore.

Amyloid-β has not yet been found in preparations that were placed in growth hormone research. Aside from that, scientists were not yet able to look into the potential fact that the main indication of the neurosurgery could have contributed to the amyloid pathology detected.

If the theory is true, however, scientists say it is going to have vital clinical implications. For example, since amyloid-β proteins are very sticky, it cannot be removed from surgical equipment even with standard sterilization techniques.

In the end, the researchers said more systematic investigations are needed to determine if the seeding hypothesis of Alzheimer's is indeed accurate.

Photo: Artur Bergman | Flickr