The development of methods for the early diagnosis of Alzheimer's disease is an important challenge for neuroscientists, and could provide a potential therapeutic window before irreversible neurodegeneration occurs. Efforts to achieve this have mainly focused on the detection of amyloid-β plaques, the accumulation of which is a key feature of Alzheimer's disease that occurs before the onset of overt neurological symptoms. However, until now the visualization of amyloid-β plaques has not been achieved at a sufficiently high contrast and specificity in living brains. A recent study published in Nature Neuroscience takes us a step closer to meeting this challenge with an MRI approach for visualizing amyloid plaques in living mice.

Higuchi and co-workers had previously created a fluorine-containing compound, known as FSB, which specifically binds to amyloid-β plaques. They used a well-established transgenic mouse model of Alzheimer's disease in which amyloid precursor protein is overexpressed, leading to a rapid build-up of amyloid-β. Intravenous delivery of FSB into these mice and the use of fluorine-sensitive MRI methods revealed amyloid deposits in the hippocampus and entorhinal cortex. This distribution of FSB was later confirmed with immunohistological analyses.

Importantly, the authors showed that the quantities of FSB required for detection using this method are not associated with toxic side effects. This MRI-based approach could, therefore, provide a potentially useful diagnostic tool for Alzheimer's disease, with the advantages of good spatial resolution and the avoidance of radioactive tracers.

As the authors recognize, before this technology can be assessed in human clinical trials, there is a need for tracers with better pharmacokinetic properties and MRI compatibility, as well as further improvements in MRI specificity and sensitivity. However, this new work not only paves the way for such developments, but it also provides a valuable tool for tracking the progression of disease and assessing the efficacy of potential therapeutic interventions in mouse models of Alzheimer's disease.