Amyloid fibers are self-assembling proteins whose fibrillar structure first attracted attention because their accumulation as amyloid deposits in the brain has been demonstrated in the case of neurodegenerative diseases (Alzheimer's, Parkinson's, mad cow disease). Their
in vivo detection is an essential research axis for the diagnosis of diseases associated with the accumulation of amyloid deposits: amyloses. Indeed, in the case of Alzheimer's and Parkinson's diseases, a diagnosis is necessary not only for better medical care but also for the development of new treatments.
During a
collaboration, researchers at IRIG have highlighted the luminescence properties of amyloid fibers ranging from visible to near infrared. In blue, this luminescence makes it possible to detect amyloid deposits in a section of the human brain (Figure, left) without any labeling and to observe their three-dimensional structure.
Left image: Confocal microscopy image of an
ex vivo amyloid deposition on a section of a brain of a person with Alzheimer's disease in the hippocampus region. 3D modeling of the amyloid deposit from 60 sections detected in the blue. (Boxed) A typical section of the amyloid deposit. The scale bars correspond to 5 µm.
Center and right images: Detection of amyloid deposits in live animals by 3D NIR imaging in "Alzheimer" mice (center) and in control mice (right).
In the near infrared,
i.e. in the diagnostic window, this signal allowed the detection of amyloid deposits in the skulls of living mice that developed Alzheimer's disease (Figure, right). This observation could thus constitute a new tool for screening and diagnosis for Alzheimer's and other amyloid-deposited diseases such as type 2 diabetes and systemic amyloidosis.
Collaborations: This work is the result of a collaboration between Grenoble-Alpes Université, Inserm, CNRS, INP Grenoble, Synchrotron Grenoble, University of Cergy-Pontoise and the Geneva Medical School (Switzerland).