Researchers, including those of Indian origin, have developed a non-invasive method that can detect Alzheimer's disease in a living animal, well before typical symptoms appear.
An interdisciplinary team of Northwestern University scientists and engineers have developed a noninvasive MRI (magnetic resonance imaging) probe that pairs a magnetic nanostructure (MNS) with an antibody that seeks out the amyloid beta brain toxins responsible for onset of Alzheimer's disease.
The accumulated toxins, because of the associated magnetic nanostructures, show up as dark areas in MRI scans of the brain.
"We have a new brain imaging method that can detect the toxin that leads to Alzheimer's disease," said neuroscientist William L Klein who led the research team along with materials scientist Vinayak P Dravid.
"Using MRI, we can see the toxins attached to neurons in the brain. We expect to use this tool to detect this disease early and to help identify drugs that can effectively eliminate the toxin and improve health," Klein said.
The new MRI probe technology is detecting something different from conventional technology: toxic amyloid beta oligomers instead of plaques, which occur at a stage of Alzheimer's when therapeutic intervention would be very late.
Amyloid beta oligomers now are widely believed to be the culprit in the onset of Alzheimer's disease and subsequent memory loss.
In a diseased brain, the mobile amyloid beta oligomers attack the synapses of neurons, destroying memory and ultimately resulting in neuron death.
As time progresses, the amyloid beta builds up and starts to stick together, forming the amyloid plaques that current probes target. Oligomers may appear more than a decade before plaques are detected.
"Non-invasive imaging by MRI of amyloid beta oligomers is a giant step forward towards diagnosis of this debilitating disease in its earliest form," said Dravid, the Abraham Harris Professor of Materials Science and Engineering at the McCormick School of Engineering and Applied Science.
"This MRI method could be used to determine how well a new drug is working. If a drug is effective, you would expect the amyloid beta signal to go down," Dravid said.
The nontoxic MRI probe was delivered intranasally to mouse models with Alzheimer's disease and control animals without the disease.
In animals with Alzheimer's, the toxins' presence can be seen clearly in the hippocampus in MRI scans of the brain. No dark areas, however, were seen in the hippocampus of the control group.
Researchers Ruchi Sureka, Mrinmoy De, Shaleen Vasavada, Sreyesh Satpathy, Summer Wu, Hrushikesh Joshi and Pottumarthi Prasad also worked on the study published in the journal Nature Nanotechnology.