Pathophysiology of hydrocefalus idiopathic normal pressure (part 3) lymphatic system

Abstract

The drainage of solutes pathways of the central nervous system (CNS) involved in the exchange between the interstitial fluid and the cerebrospinal fluid (ISF-CSF), generating a state of homeostasis. Alterations in this homeostatic system, affects solute removal of the interstitial space as the βa peptide and tau protein which are neurotoxic substances for the CNS. It have been used Experimental techniques to analyze the exchange between the ISF-CSF, which reveal that this exchange has a well organized structure. Solute removal of the CNS doesn’t have itself an anatomical structure by his own, it has been discovered pathways through fluorescent markers in the subarachnoid space, base cisterns and ventricular system that allow us to observe there’s a widely number of pathways distributed in the brain. The knowledge of this shown us how the CSF has a lymphatic function due to the exchange with the ISF along the paravascular spaces. These spaces surrounding the arterial surface, the Virchow-Robin spaces an the AQP-4 contained in the astrocyte foot, facilitate the entry of CSF para-arterial and the clearance of para-venous ISF in the brain. The flow and direction the CSF that it makes by this brain structures is probably driven by the arterial pulsation. This function will be who leads the elimination of these neurotoxic substances. Based on the dependence of this flow for the substances elimination it has been proposed that the pathways system will called “the glymphatic pathway”. The literature and the limitations found in this review are given by the method of search that has been conducted mainly in PubMed using the following terms Mesh: Cerebral Arterial Pulsation, the brain via paravascular, drainage of amyloid-beta, bulk flow of brain interstitial fluid, radiolabeled polyethylene glycols and albumin, amyloid-β, the perivascular astroglial sheath, Brain Glymphatic Transport.