Diagnosing Alzheimer's Using Saliva Biomarkers

    The development of advanced noninvasive techniques is a critical next step toward the continued progress of precision medicine initiatives. While saliva collection has already been in use as a medium for the collection DNA in forensic and genetic testing, could your spit provide clues to the future of brain health?

    Investigators at the Beaumont Research Institute, part of Beaumont Health in Michigan, are hopeful that their study involving small molecules in saliva will help identify those at risk of developing Alzheimer’s disease — a neurologic condition predicted to reach epidemic proportions worldwide by 2050.  The results of this new study were published recently in the Journal of Alzheimer’s Disease through an article entitled “Diagnostic Biomarkers of Alzheimer’s Disease as Identified in Saliva using 1H NMR-Based Metabolomics.”

    As Alzheimer’s currently has no cure, few reliable diagnostic tests, and is predicted to reach epidemic proportions worldwide by 2050, scientists are scrambling to develop methods that can quickly and accurately diagnose the neurodegenerative disorder. In the new study, the Beaumont researchers found that salivary molecules hold promise as reliable diagnostic biomarkers.

    “We used metabolomics, a newer technique to study molecules involved in metabolism,” explained senior study investigator Stewart Graham, Ph.D., assistant professor at Oakland University William Beaumont School of Medicine. “Our goal was to find unique patterns of molecules in the saliva of our study participants that could be used to diagnose Alzheimer’s disease in the earliest stages when treatment is considered most effective. Presently, therapies for Alzheimer’s are initiated only after a patient is diagnosed, and treatments offer modest benefits.”

    Metabolomics is used in medicine and biology for the study of living organisms. It measures large numbers of naturally occurring small molecules, called metabolites, present in the blood, saliva, and tissues. The pattern or fingerprint of metabolites in the biological sample can be used to learn about the health of the organism.

    “Our team’s study demonstrates the potential for using metabolomics and saliva for the early diagnosis of Alzheimer’s disease,” noted Dr. Graham. “Given the ease and convenience of collecting saliva, the development of accurate and sensitive biomarkers would be ideal for screening those at greatest risk of developing Alzheimer’s. In fact, unlike blood or cerebrospinal fluid, saliva is one of the most noninvasive means of getting cellular samples, and it’s also inexpensive.”

    In the current study, 29 adults were divided into three groups: mild cognitive impairment, Alzheimer’s disease, and a control group. After specimens were collected, the researchers positively identified and accurately quantified 57 metabolites. Some of the observed variances in the biomarkers were significant. From their data, the research team was able to make predictions as to those at most risk of developing Alzheimer’s.

    “We accurately identified significant concentration changes in 22 metabolites in the saliva of MCI and AD patients compared to controls,” the authors wrote. “This pilot study demonstrates the potential for using metabolomics and saliva for the early diagnosis of AD.”

    As Americans age, the number of people affected by Alzheimer’s is rising dramatically. According to the Alzheimer’s Association, by 2050, it’s estimated the number of Americans living with Alzheimer’s disease will triple to about 15-16 million. The condition’s toll not only affects millions of Americans but in 2017, it could cost the nation $259 billion.

    “Worldwide, the development of valid and reliable biomarkers for Alzheimer’s disease is considered the number one priority for most national dementia strategies,” Dr. Graham concluded. “It’s a necessary first step to design prevention and early-intervention research studies.”