In the United States, Alzheimer’s disease affects an estimated 5 million people over the age of 65 (1 in 9). However, the Alzheimer’s Association predicts that by the year 2050, this number will climb to an alarming 13.8 million people over 65 (1 in 4). Symptoms of the disease, while debilitating, do not become fully apparent until the disease has progressed beyond the early stages of development. As a result, the need for a reliable early detection system is two-fold: it could provide doctors with a tool for the diagnosis of Alzheimer’s before the symptoms get too severe, and it could enable further research into the treatment of Alzheimer’s during its early stages. Currently, the prevailing theory on the development of Alzheimer’s points to the build-up of toxic amyloid plaques in the brains of Alzheimer’s patients. The disease begins with the formation of “seeds” when amyloid-beta (Aβ) oligomers misfold, which, in turn, induce other Aβ oligomers to misfold. The resulting chain reaction forms a build-up of plaque.
A team of Northwestern University scientists, led by materials scientist Vinayak P. Dravid and neuroscientist William L. Klein, have developed a probe which could be the solution for early diagnosis of Alzheimer’s. The probe, as described in journal Nature Nanotechnology, locates the toxic “seeds” by utilizing Aβ oligomer-targeting antibodies that, when paired with magnetic nanostructures, are readily identifiable via MRI. This technique differs from conventional methods by targeting the Aβ oligomers, instead of the plaque–which forms at a much later stage of the disease, at which point treatment becomes much more troublesome. According to the research, the probe successfully reached hippocampal Aβ oligomers, and showed their position on an MRI with greater than 90 percent accuracy. Hopefully, the researchers will continue to refine the probe, enabling further research into the treatment of Alzheimer’s during it’s early stages.
From the study:
“Here, we report a sensitive molecular magnetic resonance imaging contrast probe that is specific for Aβ oligomers. We attach oligomer-specific antibodies onto magnetic nanostructures and show that the complex is stable and binds to Aβ oligomers on cells and brain tissues to give a magnetic resonance imaging signal. When intranasally administered to an Alzheimer’s disease mouse model, the probe readily reached hippocampal Aβ oligomers. In isolated samples of human brain tissue, we observed a magnetic resonance imaging signal that distinguished Alzheimer’s disease from controls. Such nanostructures that target neurotoxic Aβ oligomers are potentially useful for evaluating the efficacy of new drugs and ultimately for early-stage Alzheimer’s disease diagnosis and disease management..”
Nature Nanotechnology: Towards non-invasive diagnostic imaging of early-stage Alzheimer’s disease…