Eye Scans May Reveal AD

Neuroptix of Acton, Mass., is developing a noninvasive laser procedure that combines laser-induced scatter and fluorescence measurements to detect the presence of a protein known to accumulate in the brain and eyes of Alzheimer's patients.

Alzheimer's disease (AD) is characterized by the accumulation of toxic deposits of the protein Beta-amyloid (BA) in the brain. A discovery that BA forms in the lens of the eye in AD patients is the basis of the device.

The company presented data at the 28th Annual Conference of the American Society for Laser Medicine and Surgery, held last month in Kissimmee, Fla. It said results in the lab are encouraging.

Evan Sherr, vice president of product management at Neuroptix, said, "While physical exams and cognitive tests, such as intelligence and memory tests, can lead to a diagnosis of probable Alzheimer's, there is a need for a better diagnostic tool . . . to more accurately detect the disease at an earlier stage."

Using simulations of eye protein to test the scatter and fluorescence systems, Sherr filled test tubes with saline, methoyx-X04 (a compound used to label BA) and plastic beads that prior research found mimics the particle size range of BA found in the eye. BA is a large-sized protein, considerably larger than normal eye lens proteins or those that would indicate the presence of other diseases, such as cataract. Test tubes filled solely with distilled water served as the study control to determine the background signals of the device.

"Dynamic light scattering and fluorescence detection were used together to measure and distinguish the 1 µ-sized particles (or about 1/10 of a human cell) that would be considered representative of eye-based BA," Neuroptix said in a statement. "The coherent 405/500-nm laser wavelength caused the formulated eyedrop solution containing Methoxy-X04 to fluoresce when the BA particles were detected."

A small-animal study validated the initial laboratory findings, Sherr said -- the device was able to distinguish between mice that had BA accumulation in the lens of the eye and mice that did not.

"In our research, the eye acts as a mirror to the brain rather than the soul," he added. "The BA particles do not change the appearance of the eye until the disease is very advanced, so you can't see them simply by looking at the eye. However, the diagnostic device we used contains a laser with a certain wavelength that could cause these tagged proteins to glow without causing any disruption to the eye."

The company said it hopes hope the device can be used for diagnostics, detection and treatment of AD before the condition progresses; it expects to begin clinical trials of the device and its eyedrop solution this year.

For more information, visit: neuroptix.com