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Cerebral arterial pulsatility is linked to hippocampal microvascular function and episodic memory in healthy older adults

Microvascular damage in the hippocampus is emerging as a central cause of cognitive decline and dementia in aging. This could be a consequence of age-related decreases in vascular elasticity, exposing hippocampal capillaries to excessive cardiac-related pulsatile flow that disrupts the blood-brain b...

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Detalles Bibliográficos
Autores principales: Vikner, Tomas, Eklund, Anders, Karalija, Nina, Malm, Jan, Riklund, Katrine, Lindenberger, Ulman, Bäckman, Lars, Nyberg, Lars, Wåhlin, Anders
Formato: Online Artículo Texto
Lenguaje:English
Publicado: SAGE Publications 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8217890/
https://www.ncbi.nlm.nih.gov/pubmed/33444091
http://dx.doi.org/10.1177/0271678X20980652
Descripción
Sumario:Microvascular damage in the hippocampus is emerging as a central cause of cognitive decline and dementia in aging. This could be a consequence of age-related decreases in vascular elasticity, exposing hippocampal capillaries to excessive cardiac-related pulsatile flow that disrupts the blood-brain barrier and the neurovascular unit. Previous studies have found altered intracranial hemodynamics in cognitive impairment and dementia, as well as negative associations between pulsatility and hippocampal volume. However, evidence linking features of the cerebral arterial flow waveform to hippocampal function is lacking. We used a high-resolution 4D flow MRI approach to estimate global representations of the time-resolved flow waveform in distal cortical arteries and in proximal arteries feeding the brain in healthy older adults. Waveform-based clustering revealed a group of individuals featuring steep systolic onset and high amplitude that had poorer hippocampus-sensitive episodic memory (p = 0.003), lower whole-brain perfusion (p = 0.001), and weaker microvascular low-frequency oscillations in the hippocampus (p = 0.035) and parahippocampal gyrus (p = 0.005), potentially indicating compromised neurovascular unit integrity. Our findings suggest that aberrant hemodynamic forces contribute to cerebral microvascular and hippocampal dysfunction in aging.