The physiology and pathophysiology of cerebrospinal fluid: new evidence

This issue of the Croatian Medical Journal is dedicated to advancements in the diagnostics and treatment of neurosurgical diseases. The issue features some of the articles that were originally envisaged as lectures to be delivered at a joint meeting of Croatian and Japanese Neurosurgical Societies on the topic of cerebrospinal fluid (CSF) physiology and pathophysiology. The meeting entitled Physiology and Pathophysiology of Cerebrospinal Fluid – New Evidence was scheduled to be held in Vodice, Croatia, 2020, but was postponed due to the COVID-19 pandemic. Two parts of the meeting were planned: Cerebrospinal Fluid Volume Regulation and Movement – Revision of Classical Concept and Pathophysiology of Hydrocephalus – New Insights. The first part was to be dedicated to the role of the choroid plexus in physiology and pathophysiology. The classical concept defines the choroid plexus as the main CSF source (1,2), while a more recent theory, although not negating the importance of the choroid plexus in CSF formation, attributes to this organ a much lesser role than previously believed. The new theory postulates that what is important for CSF formation is the influx and exchange of fluid at the capillary level in the central nervous system (1,3-7). Furthermore, the first part of the meeting aimed to discuss the research on the fate of molecules applied in different parts of the CSF system with or without a blockade of the transport systems in various animal models, from genetically modified mice fetuses (8,9) to large experimental animals (rabbits, cats, dog, pigs) (4-6,10). Mice fetus exper