Retinal functional ultrasound imaging (rfUS) for assessing neurovascular alterations: a pilot study on a rat model of dementia

Clementine Morisset (1) , Alexandre Dizeux (1) , Benoit Larrat (2) , Erwan Selingue (2) , Herve Boutin (3, 4) , Serge Picaud (5) , Jose-Alain Sahel (5, 6, 7) , Nathalie Ialy-Radio (1) , Sophie Pezet (1) , Mickael Tanter (1) , Thomas Deffieux (1)

1 PhysMed Paris - Physique pour la médecine
2 BAOBAB - Building large instruments for neuroimaging: from population imaging to ultra-high magnetic fields
3 University of Manchester [Manchester]
4 WMIC - Wolfson Molecular Imaging Centre
5 Institut de la Vision
6 University of Pittsburgh School of Medicine
7 Fondation Ophtalmologique Adolphe de Rothschild [Paris]

Fifty million people worldwide are affected by dementia, a heterogeneous neurodegenerative condition encompassing diseases such as Alzheimer's, vascular dementia, and Parkinson's. For them, cognitive decline is often the first marker of the pathology after irreversible brain damage has already occurred. Researchers now believe that structural and functional alterations of the brain vasculature could be early precursors of the diseases and are looking at how functional imaging could provide an early diagnosis years before irreversible clinical symptoms. In this preclinical pilot study, we proposed using functional ultrasound (fUS) on the retina to assess neurovascular alterations noninvasively, bypassing the skull 19515limitation. We demonstrated for the first time the use of functional ultrasound in the retina and applied it to characterize the retinal hemodynamic response function in vivo in rats following a visual stimulus. We then demonstrated that retinal fUS could measure robust neurovascular coupling alterations between wild-type rats and TgF344-AD rat models of Alzheimer's disease. We observed an average relative increase in blood volume of 21% in the WT versus 37% for the TG group (p = 0.019). As a portable, non-invasive and inexpensive technique, rfUS is a promising functional screening tool in clinics for dementia years before symptoms.

Domaines: Neurobiologie

Clementine Morisset, Alexandre Dizeux, Benoit Larrat, Erwan Selingue, Herve Boutin, et al.. Retinal functional ultrasound imaging (rfUS) for assessing neurovascular alterations: a pilot study on a rat model of dementia. Scientific Reports, 2022, 12, pp.19515. ⟨10.1038/s41598-022-23366-8⟩. ⟨hal-03912285⟩