Does neonatal cerebrospinal fluid absorption occur via arachnoid projections or extracranial lymphatics?

Arachnoid villi and granulations are thought to represent the primary sites where cerebrospinal fluid (CSF) is absorbed. However, these structures do not appear to exist in the fetus but begin to develop around the time of birth and increase in number with age. With the use of a constant pressure-pe...

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Bibliographic Details
Published in:American journal of physiology. Regulatory, integrative and comparative physiology integrative and comparative physiology, 2002-10, Vol.52 (4), p.R869-R876
Main Authors: PAPAICONOMOU, C, BOZANOVIC-SOSIC, R, ZAKHAROV, A, JOHNSTON, M
Format: Article
Language:English
Subjects:
Biological and medical sciences
Cerebral circulation. Blood-brain barrier. Choroid plexus. Cerebrospinal fluid. Circumventricular organ. Meninges
Fundamental and applied biological sciences. Psychology
Lymphatic system
Prenatal development
Sheep
Spine
Vertebrates: nervous system and sense organs
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Summary:Arachnoid villi and granulations are thought to represent the primary sites where cerebrospinal fluid (CSF) is absorbed. However, these structures do not appear to exist in the fetus but begin to develop around the time of birth and increase in number with age. With the use of a constant pressure-perfusion system in 2- to 6-day-old lambs, we observed that global CSF transport (0.012 plus/minus 0.003 ml-min1-cmH2O1) and CSF outflow resistance (96.5 plus/minus 17.8 cmH2O-ml1-min) were very similar to comparable measures in adult animals despite the relative paucity of arachnoid villi at this stage of development. In the neonate, the recovery patterns of a radioactive protein CSF tracer in various lymph nodes and tissues indicated that CSF transport occurred through multiple lymphatic pathways. An especially important route was transport through the cribriform plate into extracranial lymphatics located in the nasal submucosa. To investigate the importance of the cribriform route in cranial CSF clearance, the cranial CSF compartment was isolated surgically from its spinal counterpart. When the cribriform plate was sealed extracranially under these conditions, CSF transport was impaired significantly. These data demonstrate an essential function for lymphatics in neonatal CSF transport and imply that arachnoid projections may play a limited role earlier in development.
ISSN:0363-6119
1522-1490