Functional ultrasound (fUS) imaging of Vascular Density and Neurovascular Coupling in Aged Mice

Aging is intricately linked to changes in neurovascular function and vascular architecture, significantly impacting cerebral blood flow (CBF) and cognitive health. The age-related changes occurring in the cerebrovasculature are key players in the pathophysiology of vascular cognitive impairment and dementia (VCID), yet visualizing deep cerebrovascular structures and CBF in the aging brain in vivo remains challenging. This study leverages cutting-edge functional ultrasound (fUS) imaging to assess and compare neurovascular coupling (NVC), tissue perfusion, functional connectomics, and vascular density between young and aged C57Bl/6 mice. In this study, we assessed cerebrovascular differences between young (4-6 months) and aged (24 months) mice. To facilitate and effectively compare fUS imaging parameters across age groups, we surgically implanted a polymethylpentene window in place of the animal's skull and securely sutured the incision. We then conducted fUS imaging to analyze variations in CBF. Additionally, we injected the mice with microbubbles ultrasound contrast agent used to enhance the imaging quality. These microbubbles consist of a lipid shell encasing a perfluoropropane gas core to increase the echogenicity of the blood, allowing for improved visualization of CBF. Preliminary results indicate a pronounced decline in NVC responses and a reduction in vascular density in older mice. Furthermore, alterations in functional connectivity and perfusion patterns emerged, correlating with aging. These findings underscore the potential of fUS as a non-invasive tool for deepening our understanding of the neurovascular underpinnings of cognitive aging. This study provides insights into the aging brain's vascular and functional changes highlighting the potential of fUS imaging in aging research. Funding: NIH R03AG070479, K01AG073614, R21AG080775, AHA (CDA941290 and 24TPA1299954), Hevolution/AFAR. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.