Perivascular spaces and brain waste clearance systems: relevance for neurodegenerative and cerebrovascular pathology

AbstractPerivascular spaces (PVS) of the brain, often called Virchow-Robin spaces, comprise fluid, cells and connective tissue, and are externally limited by astrocytic endfeet. PVS are involved in clearing brain waste and belong to the “glymphatic” system and/or the “intramural periarterial drainage” pathway through the basement membranes of the arteries. Related brain waste clearance systems include the blood–brain barrier, scavenger cells, cerebrospinal fluid, perineural lymphatic drainage pathways and the newly charac terised meningeal lymphatic vessels. Any functional abnormality of PVS or related clearance systems might lead to accumulation of brain waste. It has been postulated that PVS enlargement can be secondary to accumulation of β-amyloid. Lack of integrity of the vascular wall, microbleeds, cerebral amy loid angiopathy (CAA) and enlarged PVS often occur in the preclinical stages of Alzheimer’s disease, preceding substantial brain atrophy. PVS enlargement in the form ofétat criblé at the basal ganglia has also been considered to reflect focal atrophy, most probably secondary to ischaemic injury, based upon both pathological and imaging arguments. In addition, distinct topographic patterns of enlarged PVS are related to different types of microangiopathy: CAA is linked to enlarged juxtacortical PVS, whereas subjects with vascular risk factors tend to have enlarged PVS in the basal ganglia. Therefore, enlarged PVS are progressively being regarded as a...
Source: Neuroradiology - Category: Radiology Source Type: research