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Hladky SB, Barrand MA. Regulation of brain fluid volumes and pressures: basic principles, intracranial hypertension, ventriculomegaly and hydrocephalus. Fluids Barriers CNS 2024; 21:57. [PMID: 39020364 PMCID: PMC11253534 DOI: 10.1186/s12987-024-00532-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 03/21/2024] [Indexed: 07/19/2024] Open
Abstract
The principles of cerebrospinal fluid (CSF) production, circulation and outflow and regulation of fluid volumes and pressures in the normal brain are summarised. Abnormalities in these aspects in intracranial hypertension, ventriculomegaly and hydrocephalus are discussed. The brain parenchyma has a cellular framework with interstitial fluid (ISF) in the intervening spaces. Framework stress and interstitial fluid pressure (ISFP) combined provide the total stress which, after allowing for gravity, normally equals intracerebral pressure (ICP) with gradients of total stress too small to measure. Fluid pressure may differ from ICP in the parenchyma and collapsed subarachnoid spaces when the parenchyma presses against the meninges. Fluid pressure gradients determine fluid movements. In adults, restricting CSF outflow from subarachnoid spaces produces intracranial hypertension which, when CSF volumes change very little, is called idiopathic intracranial hypertension (iIH). Raised ICP in iIH is accompanied by increased venous sinus pressure, though which is cause and which effect is unclear. In infants with growing skulls, restriction in outflow leads to increased head and CSF volumes. In adults, ventriculomegaly can arise due to cerebral atrophy or, in hydrocephalus, to obstructions to intracranial CSF flow. In non-communicating hydrocephalus, flow through or out of the ventricles is somehow obstructed, whereas in communicating hydrocephalus, the obstruction is somewhere between the cisterna magna and cranial sites of outflow. When normal outflow routes are obstructed, continued CSF production in the ventricles may be partially balanced by outflow through the parenchyma via an oedematous periventricular layer and perivascular spaces. In adults, secondary hydrocephalus with raised ICP results from obvious obstructions to flow. By contrast, with the more subtly obstructed flow seen in normal pressure hydrocephalus (NPH), fluid pressure must be reduced elsewhere, e.g. in some subarachnoid spaces. In idiopathic NPH, where ventriculomegaly is accompanied by gait disturbance, dementia and/or urinary incontinence, the functional deficits can sometimes be reversed by shunting or third ventriculostomy. Parenchymal shrinkage is irreversible in late stage hydrocephalus with cellular framework loss but may not occur in early stages, whether by exclusion of fluid or otherwise. Further studies that are needed to explain the development of hydrocephalus are outlined.
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Affiliation(s)
- Stephen B Hladky
- Department of Pharmacology, Tennis Court Rd, Cambridge, CB2 1PD, UK.
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Duy PQ, Rakic P, Alper SL, Robert SM, Kundishora AJ, Butler WE, Walsh CA, Sestan N, Geschwind DH, Jin SC, Kahle KT. A neural stem cell paradigm of pediatric hydrocephalus. Cereb Cortex 2023; 33:4262-4279. [PMID: 36097331 PMCID: PMC10110448 DOI: 10.1093/cercor/bhac341] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Revised: 07/12/2022] [Accepted: 08/02/2022] [Indexed: 12/25/2022] Open
Abstract
Pediatric hydrocephalus, the leading reason for brain surgery in children, is characterized by enlargement of the cerebral ventricles classically attributed to cerebrospinal fluid (CSF) overaccumulation. Neurosurgical shunting to reduce CSF volume is the default treatment that intends to reinstate normal CSF homeostasis, yet neurodevelopmental disability often persists in hydrocephalic children despite optimal surgical management. Here, we discuss recent human genetic and animal model studies that are shifting the view of pediatric hydrocephalus from an impaired fluid plumbing model to a new paradigm of dysregulated neural stem cell (NSC) fate. NSCs are neuroprogenitor cells that comprise the germinal neuroepithelium lining the prenatal brain ventricles. We propose that heterogenous defects in the development of these cells converge to disrupt cerebrocortical morphogenesis, leading to abnormal brain-CSF biomechanical interactions that facilitate passive pooling of CSF and secondary ventricular distention. A significant subset of pediatric hydrocephalus may thus in fact be due to a developmental brain malformation leading to secondary enlargement of the ventricles rather than a primary defect of CSF circulation. If hydrocephalus is indeed a neuroradiographic presentation of an inborn brain defect, it suggests the need to focus on optimizing neurodevelopment, rather than CSF diversion, as the primary treatment strategy for these children.
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Affiliation(s)
- Phan Q Duy
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Medical Scientist Training Program, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Pasko Rakic
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Seth L Alper
- Division of Nephrology and Vascular Biology Research Center, Beth Israel Deaconess Medical Center and Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - Stephanie M Robert
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Adam J Kundishora
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA
| | - William E Butler
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Christopher A Walsh
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Department of Pediatrics, and Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, MA 02115, USA
- Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Nenad Sestan
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Daniel H Geschwind
- Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Sheng Chih Jin
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Kristopher T Kahle
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA 02114, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Harvard Center for Hydrocephalus and Neurodevelopmental Disorders, Massachusetts General Hospital, Boston, MA 02114, USA
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Goffin C, Leonhardt S, Radermacher K. The Role of a Dynamic Craniospinal Compliance in NPH—A Review and Future Challenges. IEEE Rev Biomed Eng 2017; 10:310-322. [DOI: 10.1109/rbme.2016.2620493] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Keong NCH, Pena A, Price SJ, Czosnyka M, Czosnyka Z, Pickard JD. Imaging normal pressure hydrocephalus: theories, techniques, and challenges. Neurosurg Focus 2016; 41:E11. [DOI: 10.3171/2016.7.focus16194] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The pathophysiology of NPH continues to provoke debate. Although guidelines and best-practice recommendations are well established, there remains a lack of consensus about the role of individual imaging modalities in characterizing specific features of the condition and predicting the success of CSF shunting. Variability of clinical presentation and imperfect responsiveness to shunting are obstacles to the application of novel imaging techniques. Few studies have sought to interpret imaging findings in the context of theories of NPH pathogenesis. In this paper, the authors discuss the major streams of thought for the evolution of NPH and the relevance of key imaging studies contributing to the understanding of the pathophysiology of this complex condition.
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Affiliation(s)
- Nicole C. H. Keong
- 1Department of Neurosurgery, National Neuroscience Institute and Duke-NUS Medical School, Singapore
- 2Neurosurgical Division, Department of Clinical Neurosciences, University of Cambridge, United Kingdom; and
| | - Alonso Pena
- 3SDA Bocconi School of Management, Milan, Italy
| | - Stephen J. Price
- 2Neurosurgical Division, Department of Clinical Neurosciences, University of Cambridge, United Kingdom; and
| | - Marek Czosnyka
- 2Neurosurgical Division, Department of Clinical Neurosciences, University of Cambridge, United Kingdom; and
| | - Zofia Czosnyka
- 2Neurosurgical Division, Department of Clinical Neurosciences, University of Cambridge, United Kingdom; and
| | - John D. Pickard
- 2Neurosurgical Division, Department of Clinical Neurosciences, University of Cambridge, United Kingdom; and
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Pickard JD, Pena A. Biomechanical modeling of hydrocephalus and idiopathic intracranial hypertension. J Neurosurg 2016; 124:879-80. [PMID: 26722862 DOI: 10.3171/2015.7.jns151726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- John D Pickard
- University of Cambridge, Cambridge, United Kingdom; and ,SDA Bocconi School of Management, Milan, Italy
| | - Alonso Pena
- University of Cambridge, Cambridge, United Kingdom; and ,SDA Bocconi School of Management, Milan, Italy
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Shim JW, Sandlund J, Madsen JR. VEGF: a potential target for hydrocephalus. Cell Tissue Res 2014; 358:667-83. [PMID: 25146955 DOI: 10.1007/s00441-014-1978-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 07/28/2014] [Indexed: 12/13/2022]
Abstract
Growth factors are primarily responsible for the genesis, differentiation and proliferation of cells and maintenance of tissues. Given the central role of growth factors in signaling between cells in health and in disease, it is understandable that disruption of growth factor-mediated molecular signaling can cause diverse phenotypic consequences including cancer and neurological conditions. This review will focus on the specific questions of enlarged cerebral ventricles and hydrocephalus. It is also well known that angiogenic factors, such as vascular endothelial growth factor (VEGF), affect tissue permeability through activation of receptors and adhesion molecules; hence, recent studies showing elevations of this factor in pediatric hydrocephalus led to the demonstration that VEGF can induce ventriculomegaly and altered ependyma when infused in animals. In this review, we discuss recent findings implicating the involvement of biochemical and biophysical factors that can induce a VEGF-mimicking effect in communicating hydrocephalus and pay particular attention to the role of the VEGF system as a potential pharmacological target in the treatment of some cases of hydrocephalus. The source of VEGF secretion in the cerebral ventricles, in periventricular regions and during pathologic events including hydrocephalus following hypoxia and hemorrhage is sought. The review is concluded with a summary of potential non-surgical treatments in preclinical studies suggesting several molecular targets including VEGF for hydrocephalus and related neurological disorders.
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Affiliation(s)
- Joon W Shim
- Department of Biology, Indiana University-Purdue University Indianapolis, 723 W. Michigan Street SL354, Indianapolis, IN, 46202, USA
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Lindvere L, Dorr A, Stefanovic B. Two-photon fluorescence microscopy of cerebral hemodynamics. Cold Spring Harb Protoc 2010; 2010:pdb.prot5494. [PMID: 20810641 DOI: 10.1101/pdb.prot5494] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Under physiological conditions, neuronal activity is tightly coupled to hemodynamics of the surrounding microvessels. Conversely, most brain diseases are associated with a disturbance in neurovascular coupling. Measuring the hemodynamic response of the microvascular network to neuronal stimulation in vivo involves two major challenges: maintaining a stable systemic physiological state in the animal and imaging with sufficient temporal and spatial resolution to capture the hemodynamic changes across the three-dimensional cortical microvascular network. Two-photon fluorescence microscopy allows imaging of intact cortex in situ at micrometer spatial and microsecond temporal resolution. However, this modality necessitates focal opening of the skull because of its high scattering of light waves. This protocol describes in detail the requisite surgical preparation and physiological maintenance of an adolescent rat with a closed cranial window. Two-photon fluorescence laser scanning microscopy is then used to image the hemodynamic response of the microvasculature of the primary somatosensory cortex to electrical stimulation of the forepaw, with the end goal of quantitative analysis of brain hemodynamics.
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Affiliation(s)
- Liis Lindvere
- Sunnybrook Research Institute, Toronto, Ontario M4N 3M5, Canada.
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Nagra G, Wagshul ME, Rashid S, Li J, McAllister JP, Johnston M. Elevated CSF outflow resistance associated with impaired lymphatic CSF absorption in a rat model of kaolin-induced communicating hydrocephalus. Cerebrospinal Fluid Res 2010; 7:4. [PMID: 20181144 PMCID: PMC2831828 DOI: 10.1186/1743-8454-7-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 02/10/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND We recently reported a lymphatic cerebrospinal fluid (CSF) absorption deficit in a kaolin model of communicating hydrocephalus in rats with ventricular expansion correlating negatively with the magnitude of the impediment to lymphatic function. However, it is possible that CSF drainage was not significantly altered if absorption at other sites compensated for the lymphatic defect. The purpose of this study was to investigate the impact of the lymphatic absorption deficit on global CSF absorption (CSF outflow resistance). METHODS Kaolin was injected into the basal cisterns of Sprague Dawley rats. The development of hydrocephalus was assessed using magnetic resonance imaging (MRI). In one group of animals at about 3 weeks after injection, the movement of intraventricularly injected iodinated human serum albumin (125I-HSA) into the olfactory turbinates provided an estimate of CSF transport through the cribriform plate into nasal lymphatics (n = 18). Control animals received saline in place of kaolin (n = 10). In a second group at about 3.5 weeks after kaolin injection, intraventricular pressure was measured continuously during infusion of saline into the spinal subarachnoid space at various flow rates (n = 9). CSF outflow resistance was calculated as the slope of the steady-state pressure versus flow rate. Control animals for this group either received no injections (intact: n = 11) or received saline in place of kaolin (n = 8). RESULTS Compared to saline injected controls, lateral ventricular volume in the kaolin group was significantly greater (0.087 +/- 0.013 ml, n = 27 versus 0.015 +/- 0.001 ml, n = 17) and lymphatic function was significantly less (2.14 +/- 0.72% injected/g, n = 18 versus 6.38 +/- 0.60% injected/g, n = 10). Additionally, the CSF outflow resistance was significantly greater in the kaolin group (0.46 +/- 0.04 cm H2O microL(-1) min, n = 9) than in saline injected (0.28 +/- 0.03 cm H2O microL(-1) min, n = 8) or intact animals (0.18 +/- 0.03 cm H2O microL(-1) min, n = 11). There was a significant positive correlation between CSF outflow resistance and ventricular volume. CONCLUSIONS The data suggest that the impediment to lymphatic CSF absorption in a kaolin-induced model of communicating hydrocephalus has a significant impact on global CSF absorption. A lymphatic CSF absorption deficit would appear to play some role (either direct or indirect) in the pathogenesis of ventriculomegaly.
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Affiliation(s)
- Gurjit Nagra
- Brain Sciences Program, Department of Laboratory Medicine and Pathobiology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Mark E Wagshul
- Department of Radiology, Stony Brook University, Stony Brook, NY, USA
- Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Shams Rashid
- Department of Radiology, Stony Brook University, Stony Brook, NY, USA
- Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Jie Li
- Department of Neurological Surgery, Wayne State University School of Medicine, University Health Center, St Antoine Detroit, MI, USA
| | - J Pat McAllister
- Department of Neurosurgery, Division of Pediatric Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Miles Johnston
- Brain Sciences Program, Department of Laboratory Medicine and Pathobiology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
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