Trying to Discover Alzheimer's Origins

Over 25 million people are afflicted by Alzheimer's disease worldwide. And most of them were diagnosed after the disease had advanced to its later stages because early diagnosis is nearly impossible at this time.  Researchers at the National Institute of Standards and Technology (NIST) and three collaborating institutions offer a better understanding of this disease's biological underpinnings that may allow for earlier detection.

They have developed a laboratory model, seen above, that recreates a simplified version of the membrane surrounding neurons in the brain. This allows them to learn how a protein long suspected of a role in early-stage Alzheimer's disease actually impairs a neuron’s structure and function.

The system is built by first covering a silica surface with gold. Sulfur atoms, which bond well to gold, are then added to act as anchors to hold the bilayer membrane. The result is a stable, tethered membrane with an aqueous environment on both sides that accurately models the behavior of the nerve cell membrane.

The data, reported in the Biophysical Journal, support the hypothesis that membrane "leakiness" is not due to a permanent hole being formed but rather due to particles, known as amyloid beta peptides, which build up in the membrane. Like a baton handed off by relay runners, this aggregate lets sodium and potassium ions pass from peptide to peptide across the bilayer.

-- LiveScience Staff

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Image Credit: National Institute of Standards and Technology (NIST)