Researchers from the Monell Center recently collaborated with the U.S. Department of Agriculture (USDA), and other institutions to do a study on odor as a biomarker for Alzheimer’s disease. The study was conducted on mouse models.
Alzheimer’s is the most common form of dementia, and close to 5.1 million Americans over the age of 65 are affected by this debilitating disease. And so far, there is no test to definitively diagnose the condition in living persons. Although the progression of Alzheimer’s cannot be stopped or reversed, an accurate early diagnosis will help patients and their families plan for the future and seek symptomatic relief.
In the current study, the researchers studied three separate mouse models, known as APP mice, which mimic Alzheimer’s-related brain pathology. They discovered that a significant development of Alzheimer-related brain pathology in the mice was preceded by a uniquely identifiable odor signature in the mice’s urine.
Incorporating both behavioral and chemical analyses, the researchers identified that all the strains of the APP mice produced urine odor profiles that were different from those of control mice
The odor differences between the control mice and the APP models were in most cases independent of age and preceded noticeable plaque build-up in the brains of the APP models. These observations suggest that the unique odor could be related to the presence of a genetic factor rather than to the actual development of the plaques in the brain.
The appearance of this unique odor signature might help develop a non-invasive method of early diagnosis of Alzheimer’s disease. This discovery could potentially allow clinicians to catch the condition before the brain decline and mental deterioration sets in. It will also help pave the way for upcoming treatments to slow early progression of the disease. The findings might also aid in the diagnosis and treatment of other diseases of the nervous system.
According to the author of the study, Bruce Kimball, PhD, this is an improvement over previous studies which focused on body odor changes caused by exogenous sources such as viruses or vaccines. Kimball, who is a chemical ecologist with the USDA National Wildlife Research Center (NWRC) and stationed at the Monell Center believes their current study proves that urinary odor signatures can be altered by Alzheimer-specific changes in the brain.
While this research is at the proof-of-concept stage, the identification of distinctive odor signatures may, in the future, provide a guide-map for human biomarkers to identify Alzheimer’s at early stages.