'Transmittable, Not Contagious': Why New Study on Alzheimer’s Is a Breakthrough

Alzheimer’s disease can be transmitted between people, but this doesn't mean it's contagious, says the new study.

Alzheimer’s disease can be transmitted between people through the transmission of amyloid-beta protein, finds a new study published in the medical journal, Nature Medicine. 

In the study, titled Iatrogenic Alzheimer’s Disease in Recipients of Cadaveric Pituitary-Derived Growth Hormone, researchers from the University College London linked a human growth hormone called the cadaver-derived human growth hormone (c-hGH) (which is extracted from the deceased people’s pituitary glands)  with Alzheimer’s disease. 

Some context: In the study, the researchers report on eight people who had been treated with c-hGH in their childhood. In five of these eight people, dementia symptoms were present, or they were already diagnosed with Alzheimer’s between the ages of 38-55 years. 

“Biomarker analyses supported the diagnoses of Alzheimer’s disease in two patients with the diagnosis, and was suggestive of Alzheimer’s in one other person; an autopsy analysis showed Alzheimer’s pathology in another patient.”

UCL researchers in the study

The use of c-hGH to treat patient was curbed in 1985 when it came to light that it could cause brain disorders such as  Creutzfeldt-Jakob disease (CJD).

In fact, through genetic testing, the researchers confirmed that the disease had not been inherited and was caused by the hormone. 

What does the growth hormone have to do with Alzheimer’s? There is strong evidence to suggest that Alzheimer’s disease is caused when the amyloid-beta protein increases in the brain with old age, or due to other risk factors.

According to the new study, the growth hormone c-hGH results in increased amounts of the protein in the brain. 

In a press release, study researcher Dr Gargi Banerjee, UCL Institute of Prion Diseases, wrote, 

"We have found that it is possible for amyloid-beta pathology to be transmitted and contribute to the development of Alzheimer’s disease."

Transmittable, not contagious: However, the researchers maintain that although it can be transmitted through hormones, Alzheimer’s disease is not contagious. It cannot be transmitted through close contact or routine medical care. 

Professor John Collinge, Director of the UCL Institute of Prion Diseases and the lead author of the study, said,

“The patients we have described were given a specific and long-discontinued medical treatment which involved injecting patients with material now known to have been contaminated with disease-related proteins.”

What next? Professor Collinge, in the press release, writes that he hopes that this research study helps review, "measures to prevent accidental transmission via other medical or surgical procedures."

“Importantly, our findings also suggest that Alzheimer's and some other neurological conditions share similar disease processes to CJD, and this may have important implications for understanding and treating Alzheimer’s disease in the future.”

Professor John Collinge