A new study of mice suggests it may be possible to detect the early stages of Alzheimer’s disease from the odour signature of urine. While there is still a lot of work to do, the researchers hope the findings will lead to a non-invasive urine test that spots the destructive brain disease before it has had time to do much damage.
Alzheimer’s disease is an irreversible, progressive brain disorder that slowly destroys memory and thinking skills, and eventually the ability to carry out the simplest tasks. It is the most common form of dementia, affecting almost 500,000 people in the UK and up to 5 million Americans. Now US scientists claim that they have found the disease leaves an odour biomarker in urine well before the significant development of other Alzheimer-related problems. The team – including members from the Monell Chemical Sense Center in Philadelphia, PA, and the US Department of Agriculture (USDA) – describes the findings in the journal Scientific Reports.
One of the authors, Dr. Bruce Kimball – a chemical ecologist with the USDA National Wildlife Research Center (NWRC), and who is based at the Monell Center – says before the new research, their work focused mostly on changes to body odour caused by factors that originate outside the body, such as viruses and vaccines. He notes, “Now we have evidence that urinary odour signatures can be altered by changes in the brain characteristic of Alzheimer’s disease. This finding may also have implications for other neurologic diseases.”
While there are currently no treatments that stop or reverse the progression of Alzheimer’s disease, an early, accurate diagnosis would give patients and their families time to plan for the future and their doctors- time to find a treatment that gives symptomatic relief.
For their study, the team worked with mice bred to develop amyloid plaques in the brain similar to the ones that afflict humans. The genes carry mutations that cause the mice’s brain cells to make too much amyloid precursor protein. The consequences are similar as seen in humans with Alzheimer’s disease. They also developed similar behavioral symptoms of mental deterioration. Using behavioral and chemical analyses, they found each strain of such mice had different urine odour signatures that were distinctly different from those of control mice.
The differences in odour signature did not vary much with age. They suggest this means the odour signature is tied to the underlying gene, rather than the progress of changes in the brain. Coauthor Dr. Daniel Wesson, a neuroscientist at Case Western Reserve University School of Medicine in Cleveland, OH, concludes, “While this research is at the proof-of-concept stage, the identification of distinctive odour signatures may someday point the way to human biomarkers to identify Alzheimer’s at early stages.”
Modified from here.