Microvascular dysfunction and aberrant network activity drive reduced brain oxygenation in a mouse tauopathy model

Area of Science:

• Neuroscience
• Neuropathology
• Vascular Biology

Background:

• Tauopathies, including Alzheimer's disease, are linked to cognitive decline due to hyperphosphorylated tau accumulation.
• Tau pathology not only causes neuronal damage but also impairs neurovascular function, contributing to disease progression.

Purpose of the Study:

• To investigate how tau pathology affects neurovascular coupling and brain oxygenation in a mouse model.
• To elucidate the relationship between neuronal hyperactivity, impaired vasodilation, and reduced oxygen availability in tauopathies.

Main Methods:

• Utilized a mouse model of tauopathy to examine neurovascular responses to neural activity.
• Assessed blood flow dynamics, capillary perfusion, and brain oxygen levels in the context of tau accumulation and network hyperactivity.

Main Results:

• Tau pathology caused a significant breakdown in activity-induced vasodilation, leading to delayed and dampened blood flow.
• Observed heterogeneous capillary perfusion, capillary stalling, and reduced oxygen availability, indicative of impaired neurovascular coupling.
• Network hyperactivity coupled with diminished oxygen delivery resulted in episodic hypoxia and disturbed metabolic homeostasis.

Conclusions:

• Reduced brain oxygenation due to an imbalance between neuronal hyperactivity and oxygen delivery is an early pathogenic event in tau accumulation.
• These findings highlight the critical role of neurovascular dysfunction in tauopathies and support therapeutic strategies aimed at improving cerebral oxygenation.