Noninvasive Laser Technology for Alzheimer's Diagnosis
A major roadblock in AD research, treatment and drug development is the lack of a safe and reliable diagnostic test. Definitive diagnosis currently involves analysis of brain tissue after death. A sensitive early diagnostic test would greatly speed testing of new drugs in animal and human treatment trials. Building on his exciting recent discoveries (Goldstein et al., Lancet, 2003) that Alzheimer's disease (AD) can be detected in the lens of the eye, Dr. Goldstein's team has developed new optical tests that can potentially diagnose and monitor the disease from the beginning stages. AD involves the accumulation of a protein called beta amyloid in the brain which also accumulates in the lens of the eye as unusual cataracts in patients with AD. These cataracts are different from those associated with aging. Dr. Goldstein has been able to non-invasively detect these special AD cataracts in humans and in an AD mouse model. His technique uses quasi-elastic light scattering (QLS) to detect cataract formation. This instrument is the most sensitive technology available to detect the very early stages of cataracts. He has also developed a complementary diagnostic technology called fluorescence ligand scanning (FLS). In this approach, he uses special eye drops that contain fluorescent image enhancing molecules that bind to beta amyloid in the lens. If beta amyloid molecules are present, the fluorescing molecules light up and are detected by the instrument. The FLS test is now undergoing evaluation in laboratory animals. The diagnostic tests will accelerate preclinical drug discovery, streamline clinical testing, and facilitate early clinical intervention. Patient care will be greatly enhanced by an objective means to establish early diagnosis, monitor disease progression, and assess treatment response.