Scientists shed new light on the spread of Alzheimer’s disease in the brain, and discovered the first evidence that it can be transmitted between people via the now-banned growth hormone for humans.
The study was published on Monday in Nature Medicine and looked at a group of patients who were treated with growth hormones extracted from cadavers between 1959-1985.
The hormones infusions had caused severe brain abnormalities due to prions, an infectious protein that causes Creutzfeldt-Jakob.
The findings show parallels in the evolution of Alzheimer’s disease and CJD. This could boost research on diagnostics and treatments to combat dementia.
The study looked at eight people who received the hormone in childhood but never developed CJD. Five of the eight patients had symptoms that were consistent with Alzheimer’s disease.
Three of the four patients had biological and autopsy tests that supported an Alzheimer’s diagnose, while a fourth showed hints.
John Collinge is the lead researcher and professor of University College London. He said that his findings suggested that Alzheimer’s disease and other neurological disorders share similar diseases processes with CJD.
He added that “this may have important implications in understanding and treating Alzheimer’s disease in future.”
According to the World Health Organization, dementia affects over 55 million people in the world.
Researchers have said that they found no evidence to suggest that Alzheimer’s disease is transmitted through daily life or normal medical care.
Researchers said that the findings indicated the growth hormone treatment of the patients had been contaminated by proteins of the type known as amyloid-beta.
The Alzheimer’s disease is increasingly believed to be caused by these proteins that stick together and create plaques which harm brain cells.
The sample size of the research was small, but scientists believe that its outline for a new mechanism in Alzheimer’s disease onset will inform the quest for diagnostics and treatment for the condition.
According to a study published in the last week, a commercially-available blood test showed high accuracy levels in early detection. Tau is another type of protein that has been implicated in Alzheimer’s.
The Nature Medicine article did not include Andrew Doig from the University of Manchester. He is a professor of biochemistry and was not involved with the Nature Medicine paper. This work supports this idea.
Researchers behind the paper say it is important to review safety measures to ensure that there is no risk of accidentally contaminating patients with amyloid beta proteins via procedures previously implicated in CJD.
After being linked to CJD the human growth hormone treatment has been banned and replaced with synthetic alternatives.
Susan Kohlhaas is the executive director for research and partnerships of Alzheimer’s Research UK.
She added, “This study has revealed new information about the spread of amyloid fragments within the brain. It provides further clues as to how Alzheimer’s progresses. And it may also provide potential targets for future treatments.”