Could a Urine Test Predict Alzheimer’s Disease?

Currently, there is no test available to definitively diagnose Alzheimer’s disease in living people. A new study from the Monell Center, the U.S. Department of Agriculture (USDA), and collaborating institutions has established differences in urine odor in mouse models of Alzheimer’s disease. The study was published in the online journal Scientific Reports. The odor signature appears in urine before significant development of Alzheimer’s ­related changes in the brain, suggesting that it could lead to the development of a non-­invasive method for early diagnosis of Alzheimer’s disease. While the disease is unique to humans, and experiments with mice require models of brain disease that mimic Alzheimer’s be created by scientists, the mouse biomarker suggests a non­invasive test could be used to detect the same thing in people. Researchers used three different types of mouse models, known as APP mice, which had been genetically altered to mimic the brain and behavioral changes seen in Alzheimer’s disease. Using both behavioral and chemical analyses, the researchers found that each strain of mice produced urinary odor profiles that could be distinguished from those of the control mice. The odor changes were not the result of new compounds being created in the body, but instead were shifts in concentrations of normal urinary compounds. The odor differences between the control mice and those with Alzheimer’s preceded detectable amounts of plaque build­up in the brains of the APP mice. Additional studies showed that the distinctive odor profiles could be used to predicatively identify APP mice versus control mice. Further, more extensive studies, are needed to identify and characterize Alzheimer’s-related odor signatures in humans.