Alzheimer’s disease (AD) is the most common form of dementia and 7th leading cause of death in North-America. It affects memory, thinking and behavior, thus causing major challenges to patients, families, society, and healthcare systems. Today, diagnosis requires expensive radioactive brain scans or spinal fluid markers obtained through harmful procedures. Blood-based markers are less harmful however they represent the whole body, not only the brain. Tear fluids from eyes are excellent potential biomarkers for AD.

Our studies on AD mice found that small pieces of genetic materials- microRNAs are similar across AD-affected brain, eye and tear fluids. We also found that the microRNAs in the AD mice tears are surprisingly identical to those reported in the spinal fluids of AD patients. Our question is: Will tears from eyes of AD patients help us to predict who is at risk, who has early-stage and who has late-stage AD.

Tear fluids will be collected from patients with mild and severe AD, non-AD dementia and healthy controls. Tears are then used to identify microRNAs using molecular techniques. By comparing the microRNAs across the groups, we will develop ways to identify which microRNAs are biomarkers for AD. Using verification methods in the AD mouse brain, eye and tear samples will further allow us to develop the translational potential of tear microRNAs for AD diagnosis.

By assessing the microRNA levels in the tears of AD, non-AD dementia patients and healthy controls, we will identify AD-related microRNA biomarkers non-invasively. Differences between mild and severe AD patients will reveal the early-stage biomarkers. These markers could have translational potential as an easily accessible, community-deployable diagnostic marker in clinical settings. It will further open up new avenues for risk prediction, treatment efficacy, and also develop microRNA-mediated therapies for AD.

We need to diagnose AD as early as possible. The eye, like the brain, is part of the central nervous system. Tears can be collected harmlessly and contain genetic materials called microRNAs. Our study will determine which microRNAs are useful in diagnosing AD even before a patient develops memory loss. Our study will discover the tear-based biomarkers of AD, an important step in diagnosing AD before brain function is lost.