Alzheimer's disease, often called "old timers disease" effects about 1 in 5 people over age 80. Called dementia, the symptoms include problems with memory, thinking, behavior, and emotion.
Researchers at Northwestern University think that the mechanism of Alzheimer's involves insulin receptors in brain cells. In the brain, insulin and insulin receptors are vital to learning and memory.
A toxic protein found in the brains of individuals with Alzheimer's removes insulin receptors from nerve cells, rendering those neurons insulin resistant.
The protein, known to attack memory-forming synapses, is called an ADDL for "amyloid ß-derived diffusible ligand." Science Daily
William L. Klein, professor of neurobiology and physiology in the Weinberg College of Arts and Sciences, said he believes the findings are a major factor in the memory deficiencies caused by ADDLs in Alzheimer's brains and reveals a fundamental new connection between diabetes and Alzheimer's disease. This offers hope for therapeutics. Finding ways to make those insulin receptors themselves resistant to the impact of ADDLs. might not be so difficult.
Klein not only helped identify the bio-marker, ADDL, but also helped develop a technique to detect it in patients with early stage Alzheimer's using bio-bar-code amplification technology.
To detect ADDLs, a magnetic microparticle and a gold nanoparticle are each outfitted with an antibody specific to the ADDL antigen. When in solution, the antibodies “recognize” and bind to the ADDL, sandwiching the protein between the two particles. Fienberg School of Medicine
After the “particle-ADDL-particle” sandwich is removed magnetically from solution, the bar-code DNA is removed from the sandwich and read using standard DNA detection methodologies. The researchers next would like to develop the technology so that the test could be done using a blood or urine sample instead of cerebrospinal fluid, which is more difficult to obtain.