Cerebral Vessels: An Overview of Anatomy, Physiology, and Role in the Drainage of Fluids and Solutes

Abstract

The cerebral vasculature is made up of highly specialized structures that assure constant brain perfusion necessary to meet the very high demand for oxygen and glucose by neurons and glial cells. A dense, redundant network of arteries is spread over the entire pial surface from which penetrating arteries dive into the cortex to reach the neurovascular units. Besides providing blood to the brain parenchyma, cerebral arteries are key in the drainage of interstitial fluid (ISF) and solutes such as amyloid-beta. This occurs along the basement membranes surrounding vascular smooth muscle cells, toward leptomeningeal arteries and deep cervical lymph nodes. The dense microvasculature is made up of fine capillaries. Capillary walls contain pericytes that have contractile properties and are lined by a highly specialized blood–brain barrier that regulates the entry of solutes and ions and maintains the integrity of the composition of ISF. They are also important for the production of ISF. Capillaries drain into venules that course centrifugally toward the cortex to reach cortical veins and empty into dural venous sinuses. The walls of the venous sinuses are also home to meningeal lymphatic vessels that support the drainage of cerebrospinal fluid, although such pathways are still poorly understood. Damage to macro- and microvasculature will compromise cerebral perfusion, hamper the highly synchronized movement of neurofluids, and affect the drainage of waste products leading to neuronal and glial degeneration. This review will present vascular anatomy, their role in fluid dynamics, and a summary of how their dysfunction can lead to neurodegeneration.

Tumor Vessels Fuel the Fire in Glioblastoma

“…Quiescent ECs organize as a monolayer with a streamlined surface and linked via junctional molecules. ECs are further ensheathed by pericytes and surrounded by a specialized basal lamina, shared with pericytes and astrocytic end-feet, and sparsely interconnected with neuronal ending and microglia [ 19 ]. The tumor ecosystem dramatically affects this stereotyped vasculature, which ultimately features tortuous, disorganized vessels, lacking physiological regulation and controlled architecture [ 20 ].…”

Microvascular Impairment in Patients With Cerebral Small Vessel Disease Assessed With Arterial Spin Labeling Magnetic Resonance Imaging: A Pilot Study

“…Additionally, we observed increased mean ATT in GM and WM in the CSVD group compared to controls. These longer ATTs may not only reflect micro- but also macrovascular changes (Dai et al, 2017 ) due to an age- and/or disease-related reduction of the alongside vessel wall stiffness (Agarwal and Carare, 2020 ) and associated increases of the vessel curvature. Indeed, at least stenoses/occlusions of the brain-supplying large arteries have been excluded in our cohort, which therefore did not drive the hemodynamic changes.…”

Perivascular Spaces, Glymphatic System and MR

“…Penetrating arterioles are completely wrapped in a sheet of pia mater. It can be observed under electron microscopy that when the penetrating arterioles branch into the level of capillaries, the basement membrane of the pial sheath and the basement membranes of the astrocytes (glia limitans) fuse together to create a perivascular compartment ( 4 ). The compartment separates the vessel from surrounding brain tissue and fill with ISF.…”