Assessment of Neurovascular Coupling & Cortical Spreading Depression in Mixed Models of Atherosclerosis & Alzheimer's Disease

Neurovascular coupling is a critical brain mechanism whereby changes to blood flow accompany localised neural activity. The breakdown of neurovascular coupling is linked to the development and progression of several neurological conditions including dementia. In this study, we examined cortical haemodynamics in preparations that modelled Alzheimers disease (J20-AD) and atherosclerosis (PCSK9-ATH) between 9-12m of age. We report novel findings with atherosclerosis where neurovascular decline is characterised by significantly reduced blood volume, levels of oxyhaemoglobin & deoxyhaemoglobin, in addition to global neuroinflammation. In the comorbid mixed model (J20-PCSK9-MIX), we report a 3x fold increase in hippocampal amyloid-beta plaques. A key finding was that cortical spreading depression (CSD) due to electrode insertion into the brain was worse in the diseased animals and led to a prolonged period of hypoxia. These findings suggest that systemic atherosclerosis can be detrimental to neurovascular health and that having cardiovascular comorbidities can exacerbate pre-existing Alzheimers-related amyloid-plaques.