![]() ![]() The clearance of metabolic proteins, such as amyloid-β, is an important process in the healthy brain: the failure of this process may be a cause of neurological disorders such as Alzheimer’s disease. Schematic diagram of the PVSs around a pial artery and a penetrating artery in the brain. Various mechanisms have been proposed as the driving force for this flow: an overall pressure gradient created by the production of CSF in the choroid plexuses a pressure gradient driven by respiration or a peristaltic flow driven by arterial pulsations due to the heartbeat, a mechanism appropriately named perivascular pumping by Hadaczek et al.įigure 1. Subsequent experiments have shown that tracers injected into the subarachnoid space are transported preferentially through periarterial spaces at rates much faster than could be explained by diffusion alone. ![]() showed that molecules of different molecular weight are cleared from the rodent brain at the same exponential decay rate, indicating bulk flow rather than diffusion as the dominant clearance mechanism. It has long been thought that a flow of CSF in these PVSs plays an important role in the clearance of solutes from the brain. Figure 1 illustrates two such PVSs, those surrounding a pial artery and a penetrating artery, for which we have the best experimental data. arteries and veins) and are filled with cerebrospinal fluid (CSF). Perivascular spaces (PVSs) in the brain are channels that surround the blood vessels (e.g. ![]()
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