Revisiting the neurovascular unit

Area of Science:

• Neuroscience
• Vascular Biology
• Cerebrovascular Research

Background:

• The neurovascular unit model explains microvessel regulation by neurons but omits larger arteries and systemic influences.
• Cerebrovascular cell heterogeneity challenges the idea of a single, uniform neurovascular unit across the entire brain vasculature.
• Existing models do not fully capture the complexity of brain blood supply and its regulation.

Purpose of the Study:

• To examine the cellular and molecular diversity of the cerebrovascular tree.
• To determine the roles of systemic and brain-intrinsic factors in neurovascular function.
• To propose an updated framework for understanding brain vascular regulation.

Main Methods:

• Review of existing literature on cerebrovascular cell types and functions.
• Analysis of molecular heterogeneity within the brain vasculature.
• Integration of data on systemic and central control of cerebral blood flow.

Main Results:

• The cerebrovascular tree exhibits significant segmental diversity in cell types and function.
• Both systemic and brain-intrinsic factors dynamically regulate neurovascular function.
• A 'neurovascular complex' model, rather than a simple unit, better describes brain vasculature.

Conclusions:

• The concept of a 'neurovascular complex' composed of diverse functional modules is supported by current evidence.
• This complex integrates central and peripheral signals for coordinated vascular responses and brain homeostasis.
• The neurovascular complex model has significant implications for understanding neurovascular regulation in health, disease, and brain imaging.