TY - JOUR
T1 - Glymphatics, Cranium, and the Brain Homeostasis
AU - Zibitt, Meira
AU - Makhoul, Vivien
AU - Yu, Jack C.
AU - Nguyen, Khoi
AU - Williams, Joseph K.
N1 - Publisher Copyright:
© The Author(s) 2023.
PY - 2023/6
Y1 - 2023/6
N2 - Despite the human brain accounting for only 2% of total body mass, it consumes 20% of the body’s energy. The average cerebral blood flow, at 70 mL/100 g/minute, is 10x the average blood flow for the rest of the body, at 7 mL/100 g/minute. With such elevated energy demands and synaptic activities, the brain produces 7000 mg of proteinaceous, lipid, and other metabolic waste per day including amyloid beta, tau, and modified cholesterol (24S-hydroxycholesterol and oxysterol, etc.). In the body, the lymphatic system eliminates metabolic wastes, but the brain parenchyma or the neuropil, contains no lymphatics. How does brain rid itself of these metabolites? The discovery of the glymphatic system a decade ago partially answers the question. The word “glymphatics” is derived by condensing “glial” and “lymphatics.” It is comprised of convective flow at 50 µm/s in the perivascular space around pia-penetrating arterioles, entering the interstitial fluid space before draining into the perivascular space of the venules, carrying with it the metabolic wastes. These perivascular spaces, also known as the Virchow-Robin spaces, allow for mixing of CSF and interstitial fluid via astrocytic aquaporin 4 (AQP4) channels, to clear metabolic wastes. The glymphatic flow is highly complex, driven by many mechanisms including the bulk flow due to CSF production, arterial pulsations, respiration, and more. Research into the glymphatic system has explored its relationships with slow wave sleep, aging, neurodegeneration, and traumatic brain injuries. This emerging area of research in glymphatic function and the impacts that craniofacial structure and cranial surgeries have on this system, especially craniosynostosis, are the subject of this review. We aim to explore the clinical considerations in craniofacial surgeries regarding glymphatics. Specifically, we discuss the significance, current limitations, and future directions of applications of glymphatics in both diagnosis and treatment of craniosynostosis.
AB - Despite the human brain accounting for only 2% of total body mass, it consumes 20% of the body’s energy. The average cerebral blood flow, at 70 mL/100 g/minute, is 10x the average blood flow for the rest of the body, at 7 mL/100 g/minute. With such elevated energy demands and synaptic activities, the brain produces 7000 mg of proteinaceous, lipid, and other metabolic waste per day including amyloid beta, tau, and modified cholesterol (24S-hydroxycholesterol and oxysterol, etc.). In the body, the lymphatic system eliminates metabolic wastes, but the brain parenchyma or the neuropil, contains no lymphatics. How does brain rid itself of these metabolites? The discovery of the glymphatic system a decade ago partially answers the question. The word “glymphatics” is derived by condensing “glial” and “lymphatics.” It is comprised of convective flow at 50 µm/s in the perivascular space around pia-penetrating arterioles, entering the interstitial fluid space before draining into the perivascular space of the venules, carrying with it the metabolic wastes. These perivascular spaces, also known as the Virchow-Robin spaces, allow for mixing of CSF and interstitial fluid via astrocytic aquaporin 4 (AQP4) channels, to clear metabolic wastes. The glymphatic flow is highly complex, driven by many mechanisms including the bulk flow due to CSF production, arterial pulsations, respiration, and more. Research into the glymphatic system has explored its relationships with slow wave sleep, aging, neurodegeneration, and traumatic brain injuries. This emerging area of research in glymphatic function and the impacts that craniofacial structure and cranial surgeries have on this system, especially craniosynostosis, are the subject of this review. We aim to explore the clinical considerations in craniofacial surgeries regarding glymphatics. Specifically, we discuss the significance, current limitations, and future directions of applications of glymphatics in both diagnosis and treatment of craniosynostosis.
KW - Virchow-Robin space
KW - cerebrospinal fluid
KW - craniofacial surgery
KW - cranioplasty
KW - craniosynostosis
KW - glymphatic
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U2 - 10.1177/27325016231160291
DO - 10.1177/27325016231160291
M3 - Review article
AN - SCOPUS:85164544410
SN - 2732-5016
VL - 4
SP - 218
EP - 227
JO - Face
JF - Face
IS - 2
ER -