Neurovasculaire

Neurovasculaire (neurovascular) denotes the integrated system of blood vessels and neural elements that supply and regulate the nervous system. It comprises the cerebral and spinal vasculature, the meningeal vessels, and the peripheral neurovascular beds, all functioning with neural tissue through the neurovascular unit.

Anatomy and function: Arteries, arterioles, capillaries, venules and veins form the vascular tree; the brain and spinal cord are protected by the blood-brain barrier and blood-spinal cord barrier, formed by endothelial cells, tight junctions, astrocyte endfeet, and pericytes. The neurovascular unit coordinates cerebral blood flow with metabolic demand, maintains ionic homeostasis, and clears metabolites.

Physiology and coupling: Neuronal activity triggers signaling cascades that dilate vessels, increasing local blood flow in a process called neurovascular coupling. Glial cells, particularly astrocytes, mediate signals between neurons and vessels; endothelial cells regulate barrier properties and leukocyte passage.

Development and pathology: The cerebrovascular system develops via angiogenesis and maturation that establish barrier integrity. Pathologies include stroke (ischemic and hemorrhagic), aneurysms, moyamoya disease, cerebral small vessel disease, vasculitis, tumor angiogenesis, and neurodegenerative diseases where vascular dysfunction contributes to progression and cognitive impairment. Retinal neurovascular units are clinically informative in diseases such as diabetic retinopathy.

Clinical relevance and imaging: Assessment uses MRI and CT angiography, perfusion imaging, and functional MRI, as well as transcranial Doppler. Understanding the neurovascular unit informs treatment strategies aimed at protecting neurons, preserving barrier integrity, and modulating blood flow.