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van Lanen RHGJ, Haeren RHL, Staals J, Dings JTA, Schijns OEMG, Hoogland G, van Kuijk SMJ, Kapsokalyvas D, van Zandvoort MAMJ, Vink H, Rijkers K. Cerebrovascular glycocalyx damage and microcirculation impairment in patients with temporal lobe epilepsy. J Cereb Blood Flow Metab 2023; 43:1737-1751. [PMID: 37231664 PMCID: PMC10581235 DOI: 10.1177/0271678x231179413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 04/02/2023] [Accepted: 05/02/2023] [Indexed: 05/27/2023]
Abstract
Temporal lobe epilepsy (TLE) is increasingly associated with blood-brain barrier dysfunction and microvascular alterations, yet the pathophysiological link is missing. An important barrier function is exerted by the glycocalyx, a gel-like layer coating the endothelium. To explore such associations, we used intraoperative videomicroscopy to quantify glycocalyx and microcirculation properties of the neocortex and hippocampus of 15 patients undergoing resective brain surgery as treatment for drug-resistant TLE, and 15 non-epileptic controls. Fluorescent lectin staining of neocortex and hippocampal tissue was used for blood vessel surface area quantification. Neocortical perfused boundary region, the thickness of the glycocalyx' impaired layer, was higher in patients (2.64 ± 0.52 µm) compared to controls (1.31 ± 0.29 µm), P < 0.01, indicative of reduced glycocalyx integrity in patients. Moreover, erythrocyte flow velocity analysis revealed an impaired ability of TLE patients to (de-)recruit capillaries in response to changing metabolic demands (R2 = 0.75, P < 0.01), indicating failure of neurovascular coupling mechanisms. Blood vessel quantification comparison between intraoperative measurements and resected tissue showed strong correlation (R2 = 0.94, P < 0.01). This is the first report on in vivo assessment of glycocalyx and microcirculation properties in TLE patients, confirming the pivotal role of cerebrovascular changes. Further assessment of the cerebral microcirculation in relation to epileptogenesis might open avenues for new therapeutic targets for drug-resistant epilepsy.
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Affiliation(s)
- Rick HGJ van Lanen
- Department of Neurosurgery, Maastricht University Medical Centre, Maastricht, The Netherlands
- School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands
| | - Roel HL Haeren
- Department of Neurosurgery, Maastricht University Medical Centre, Maastricht, The Netherlands
- School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands
| | - Julie Staals
- Department of Neurology, CARIM School for Cardiovascular Diseases, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Jim TA Dings
- Department of Neurosurgery, Maastricht University Medical Centre, Maastricht, The Netherlands
- Academic Centre for Epileptology, Maastricht University Medical Centre and Kempenhaeghe, Maastricht/Heeze, The Netherlands
| | - Olaf EMG Schijns
- Department of Neurosurgery, Maastricht University Medical Centre, Maastricht, The Netherlands
- School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands
- Academic Centre for Epileptology, Maastricht University Medical Centre and Kempenhaeghe, Maastricht/Heeze, The Netherlands
| | - Govert Hoogland
- Department of Neurosurgery, Maastricht University Medical Centre, Maastricht, The Netherlands
- School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands
| | - Sander MJ van Kuijk
- Department of Clinical Epidemiology and Medical Technology Assessment, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Dimitris Kapsokalyvas
- Department of Genetics & Cell Biology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
- Interdisciplinary Center for Clinical Research (IZKF), University Hospital RWTH Aachen, Aachen, Germany
| | - Marc AMJ van Zandvoort
- School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands
- Department of Genetics & Cell Biology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
- Institute for Molecular Cardiovascular Research IMCAR, Universitätsklinikum, Aachen University, Aachen, Germany
| | - Hans Vink
- Department of Physiology, Maastricht University, Maastricht, The Netherlands
| | - Kim Rijkers
- Department of Neurosurgery, Maastricht University Medical Centre, Maastricht, The Netherlands
- School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, The Netherlands
- Academic Centre for Epileptology, Maastricht University Medical Centre and Kempenhaeghe, Maastricht/Heeze, The Netherlands
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2
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Yang R, Chen M, Zheng J, Li X, Zhang X. The Role of Heparin and Glycocalyx in Blood-Brain Barrier Dysfunction. Front Immunol 2022; 12:754141. [PMID: 34992593 PMCID: PMC8724024 DOI: 10.3389/fimmu.2021.754141] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 11/29/2021] [Indexed: 11/13/2022] Open
Abstract
The blood-brain barrier (BBB) functions as a dynamic boundary that protects the central nervous system from blood and plays an important role in maintaining the homeostasis of the brain. Dysfunction of the BBB is a pathophysiological characteristic of multiple neurologic diseases. Glycocalyx covers the luminal side of vascular endothelial cells(ECs). Damage of glycocalyx leads to disruption of the BBB, while inhibiting glycocalyx degradation maintains BBB integrity. Heparin has been recognized as an anticoagulant and it protects endothelial glycocalyx from destruction. In this review, we summarize the role of glycocalyx in BBB formation and the therapeutic potency of heparin to provide a theoretical basis for the treatment of neurological diseases related to BBB breakdown.
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Affiliation(s)
- Rui Yang
- Department of Critical Care Medicine, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Mingming Chen
- Department of Critical Care Medicine, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Jiayin Zheng
- Department of Critical Care Medicine, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Xin Li
- Department of Critical Care Medicine, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Xiaojuan Zhang
- Department of Critical Care Medicine, The First Affiliated Hospital of China Medical University, Shenyang, China
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3
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Abstract
The structural and functional alterations of microvessels are detected because of physiological aging and in several cardiometabolic diseases, including hypertension, diabetes, and obesity. The small resistance arteries of these patients show an increase in the media or total wall thickness to internal lumen diameter ratio (MLR or WLR), often accompanied by endothelial dysfunction. For decades, micromyography has been considered as a gold standard method for evaluating microvascular structural alterations through the measurement of MLR or WLR of subcutaneous small vessels dissected from tissue biopsies. Micromyography is the most common and reliable method for assessing microcirculatory endothelial function ex vivo, while strain-gauge venous plethysmography is considered the reference technique for in vivo studies. Recently, several noninvasive methods have been proposed to extend the microvasculature evaluation to a broader range of patients and clinical settings. Scanning laser Doppler flowmetry and adaptive optics are increasingly used to estimate the WLR of retinal arterioles. Microvascular endothelial function may be evaluated in the retina by flicker light stimulus, in the finger by tonometric approaches, or in the cutaneous or sublingual tissues by laser Doppler flowmetry or intravital microscopy. The main limitation of these techniques is the lack of robust evidence on their prognostic value, which currently reduces their widespread use in daily clinical practice. Ongoing and future studies will overcome this issue, hopefully moving the noninvasive assessment of the microvascular function and structure from bench to bedside.
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Affiliation(s)
- Damiano Rizzoni
- Clinica Medica, Department of Clinical and Experimental Sciences, University of Brescia, Italy (D.R., C.A., C.D.C.).,Division of Medicine, Spedali Civili di Brescia, Montichiari (Brescia), Italy (D.R.)
| | - Alessandro Mengozzi
- Department of Clinical and Experimental Medicine, University of Pisa, Italy (A.M., S.M., A.V.).,Institute of Life Science, Sant'Anna School of Advanced Studies, Pisa, Italy (A.M.)
| | - Stefano Masi
- Department of Clinical and Experimental Medicine, University of Pisa, Italy (A.M., S.M., A.V.).,Institute of Cardiovascular Science, University College London, United Kingdom (S.M.)
| | - Claudia Agabiti Rosei
- Clinica Medica, Department of Clinical and Experimental Sciences, University of Brescia, Italy (D.R., C.A., C.D.C.)
| | - Carolina De Ciuceis
- Clinica Medica, Department of Clinical and Experimental Sciences, University of Brescia, Italy (D.R., C.A., C.D.C.)
| | - Agostino Virdis
- Department of Clinical and Experimental Medicine, University of Pisa, Italy (A.M., S.M., A.V.)
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Stoddart P, Satchell SC, Ramnath R. Cerebral microvascular endothelial glycocalyx damage, its implications on the blood-brain barrier and a possible contributor to cognitive impairment. Brain Res 2022; 1780:147804. [DOI: 10.1016/j.brainres.2022.147804] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/21/2022] [Accepted: 01/24/2022] [Indexed: 12/31/2022]
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5
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Hayden MR, Tyagi SC. Impaired Folate-Mediated One-Carbon Metabolism in Type 2 Diabetes, Late-Onset Alzheimer's Disease and Long COVID. Medicina (Kaunas) 2021; 58:16. [PMID: 35056324 PMCID: PMC8779539 DOI: 10.3390/medicina58010016] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/18/2021] [Accepted: 12/21/2021] [Indexed: 12/25/2022]
Abstract
Impaired folate-mediated one-carbon metabolism (FOCM) is associated with many pathologies and developmental abnormalities. FOCM is a metabolic network of interdependent biosynthetic pathways that is known to be compartmentalized in the cytoplasm, mitochondria and nucleus. Currently, the biochemical mechanisms and causal metabolic pathways responsible for the initiation and/or progression of folate-associated pathologies have yet to be fully established. This review specifically examines the role of impaired FOCM in type 2 diabetes mellitus, Alzheimer's disease and the emerging Long COVID/post-acute sequelae of SARS-CoV-2 (PASC). Importantly, elevated homocysteine may be considered a biomarker for impaired FOCM, which is known to result in increased oxidative-redox stress. Therefore, the incorporation of hyperhomocysteinemia will be discussed in relation to impaired FOCM in each of the previously listed clinical diseases. This review is intended to fill gaps in knowledge associated with these clinical diseases and impaired FOCM. Additionally, some of the therapeutics will be discussed at this early time point in studying impaired FOCM in each of the above clinical disease states. It is hoped that this review will allow the reader to better understand the role of FOCM in the development and treatment of clinical disease states that may be associated with impaired FOCM and how to restore a more normal functional role for FOCM through improved nutrition and/or restoring the essential water-soluble B vitamins through oral supplementation.
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Affiliation(s)
- Melvin R. Hayden
- Departments of Internal Medicine, Endocrinology Diabetes and Metabolism Diabetes and Cardiovascular Disease Center, University of Missouri School of Medicine, Columbia, MO 65212, USA
| | - Suresh C. Tyagi
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY 40202, USA;
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Pang J, Wu Y, Peng J, Yang P, Chen L, Jiang Y. Association of Pericyte Loss With Microthrombosis After Subarachnoid Hemorrhage in ApoE-Deficient Mice. Front Neurol 2021; 12:726520. [PMID: 34566870 PMCID: PMC8460864 DOI: 10.3389/fneur.2021.726520] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/19/2021] [Indexed: 11/23/2022] Open
Abstract
Background: The occurrence of microthrombosis contributes to not only delayed cerebral ischemia (DCI), but also early brain injury (EBI) after SAH. However, the underlying mechanism is not completely investigated. In the current study, we explored the underlying mechanism of microthrombosis in EBI stage after SAH in ApoE-deficient mice. Methods: Experimental SAH was established by endovascular perforation in apolipoprotein E (ApoE)-deficient mice and wild type (WT) mice. Neurobehavioral, molecular biological and histopathological methods were used to assess the relationship between pericytes loss, neurobehavioral performance, and microthrombosis. Results: We found that the number of microthrombi was significantly increased and peaked 48 h after SAH in WT mice. The increased microthrombosis was related to the decreased effective microcirculation perfusion area and EBI severity. ApoE-deficient mice showed more extensive microthrombosis than that of WT mice 48 h after SAH, which was thereby associated with greater neurobehavioral deficits. Immunohistochemical staining showed that microthrombi were predominantly located in microvessels where pericytes coverage was absent. Mechanistically, ApoE deficiency caused more extensive CypA-NF-κB-MMP-9 pathway activation than that observed in WT mice, which thereby led to more degradation of N-cadherin, and subsequently more pericytes loss. Thereafter, the major adhesion molecule that promoting microthrombi formation in microvessels, P-selectin, was considerably increased in WT mice and increased to a greater extent in the ApoE-deficient mice. Conclusion: Taken together, these data suggest that pericytes loss is associated with EBI after SAH through promoting microthrombosis. Therapies that target ApoE to reduce microthrombosis may be a promising strategy for SAH treatment.
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Affiliation(s)
- Jinwei Pang
- Department of Neurosurgery, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Yue Wu
- Department of Neurosurgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jianhua Peng
- Department of Neurosurgery, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Ping Yang
- Department of Cardiology, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Ligang Chen
- Department of Neurosurgery, The Affiliated Hospital of Southwest Medical University, Luzhou, China.,Sichuan Clinical Research Center for Neurosurgery, Luzhou, China
| | - Yong Jiang
- Department of Neurosurgery, The Affiliated Hospital of Southwest Medical University, Luzhou, China.,Sichuan Clinical Research Center for Neurosurgery, Luzhou, China.,Luzhou Key Laboratory of Neurological Diseases and Brain Function, Luzhou, China
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Schenck H, Netti E, Teernstra O, De Ridder I, Dings J, Niemelä M, Temel Y, Hoogland G, Haeren R. The Role of the Glycocalyx in the Pathophysiology of Subarachnoid Hemorrhage-Induced Delayed Cerebral Ischemia. Front Cell Dev Biol 2021; 9:731641. [PMID: 34540844 PMCID: PMC8446455 DOI: 10.3389/fcell.2021.731641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 08/06/2021] [Indexed: 12/02/2022] Open
Abstract
The glycocalyx is an important constituent of blood vessels located between the bloodstream and the endothelium. It plays a pivotal role in intercellular interactions in neuroinflammation, reduction of vascular oxidative stress, and provides a barrier regulating vascular permeability. In the brain, the glycocalyx is closely related to functions of the blood-brain barrier and neurovascular unit, both responsible for adequate neurovascular responses to potential threats to cerebral homeostasis. An aneurysmal subarachnoid hemorrhage (aSAH) occurs following rupture of an intracranial aneurysm and leads to immediate brain damage (early brain injury). In some cases, this can result in secondary brain damage, also known as delayed cerebral ischemia (DCI). DCI is a life-threatening condition that affects up to 30% of all aSAH patients. As such, it is associated with substantial societal and healthcare-related costs. Causes of DCI are multifactorial and thought to involve neuroinflammation, oxidative stress, neuroinflammation, thrombosis, and neurovascular uncoupling. To date, prediction of DCI is limited, and preventive and effective treatment strategies of DCI are scarce. There is increasing evidence that the glycocalyx is disrupted following an aSAH, and that glycocalyx disruption could precipitate or aggravate DCI. This review explores the potential role of the glycocalyx in the pathophysiological mechanisms contributing to DCI following aSAH. Understanding the role of the glycocalyx in DCI could advance the development of improved methods to predict DCI or identify patients at risk for DCI. This knowledge may also alter the methods and timing of preventive and treatment strategies of DCI. To this end, we review the potential and limitations of methods currently used to evaluate the glycocalyx, and strategies to restore or prevent glycocalyx shedding.
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Affiliation(s)
- Hanna Schenck
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Eliisa Netti
- Department of Neurosurgery, Helsinki University Hospital, Helsinki, Finland
| | - Onno Teernstra
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Inger De Ridder
- Department of Neurology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, Netherlands
| | - Jim Dings
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Mika Niemelä
- Department of Neurosurgery, Helsinki University Hospital, Helsinki, Finland
| | - Yasin Temel
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Govert Hoogland
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, Netherlands
| | - Roel Haeren
- Department of Neurosurgery, Maastricht University Medical Center, Maastricht, Netherlands.,Department of Neurosurgery, Helsinki University Hospital, Helsinki, Finland
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Hayden MR, Banks WA. Deficient Leptin Cellular Signaling Plays a Key Role in Brain Ultrastructural Remodeling in Obesity and Type 2 Diabetes Mellitus. Int J Mol Sci 2021; 22:5427. [PMID: 34063911 PMCID: PMC8196569 DOI: 10.3390/ijms22115427] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/13/2021] [Accepted: 05/15/2021] [Indexed: 12/11/2022] Open
Abstract
The triad of obesity, metabolic syndrome (MetS), Type 2 diabetes mellitus (T2DM) and advancing age are currently global societal problems that are expected to grow over the coming decades. This triad is associated with multiple end-organ complications of diabetic vasculopathy (maco-microvessel disease), neuropathy, retinopathy, nephropathy, cardiomyopathy, cognopathy encephalopathy and/or late-onset Alzheimer's disease. Further, obesity, MetS, T2DM and their complications are associated with economical and individual family burdens. This review with original data focuses on the white adipose tissue-derived adipokine/hormone leptin and how its deficient signaling is associated with brain remodeling in hyperphagic, obese, or hyperglycemic female mice. Specifically, the ultrastructural remodeling of the capillary neurovascular unit, brain endothelial cells (BECs) and their endothelial glycocalyx (ecGCx), the blood-brain barrier (BBB), the ventricular ependymal cells, choroid plexus, blood-cerebrospinal fluid barrier (BCSFB), and tanycytes are examined in female mice with impaired leptin signaling from either dysfunction of the leptin receptor (DIO and db/db models) or the novel leptin deficiency (BTBR ob/ob model).
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Affiliation(s)
- Melvin R. Hayden
- Departments of Internal Medicine, Endocrinology Diabetes and Metabolism, Diabetes and Cardiovascular Disease Center, University of Missouri-Columbia School of Medicine, One Hospital Drive, Columbia, MO 65212, USA;
| | - William A. Banks
- Geriatrics Research, Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, 1660 S. Columbian Way, 810C/Bldg 1, Seattle, WA 98108, USA
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA 98108, USA
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9
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Abstract
The negative surface charge of brain microvessel endothelial cells is derived from the special composition of their membrane lipids and the thick endothelial surface glycocalyx. They are important elements of the unique defense systems of the blood-brain barrier. The tissue-specific properties, components, function and charge of the brain endothelial glycocalyx have only been studied in detail in the past 15 years. This review highlights the importance of the negative surface charge in the permeability of macromolecules and nanoparticles as well as in drug interactions. We discuss surface charge and glycoxalyx changes in pathologies related to the brain microvasculature and protective measures against glycocalyx shedding and damage. We present biophysical techniques, including a microfluidic chip device, to measure surface charge of living brain endothelial cells and imaging methods for visualization of surface charge and glycocalyx.
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Affiliation(s)
- Fruzsina R Walter
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary.,Department of Biotechnology, University of Szeged, Szeged, Hungary
| | - Ana R Santa-Maria
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary.,Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Mária Mészáros
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Szilvia Veszelka
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - András Dér
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Mária A Deli
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
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10
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Hahn RG, Patel V, Dull RO. Human glycocalyx shedding: Systematic review and critical appraisal. Acta Anaesthesiol Scand 2021; 65:590-606. [PMID: 33595101 DOI: 10.1111/aas.13797] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/28/2021] [Accepted: 02/01/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND The number of studies measuring breakdown products of the glycocalyx in plasma has increased rapidly during the past decade. The purpose of the present systematic review was to assess the current knowledge concerning the association between plasma concentrations of glycocalyx components and structural assessment of the endothelium. METHODS We performed a literature review of Pubmed to determine which glycocalyx components change in a wide variety of human diseases and conditions. We also searched for evidence of a relationship between plasma concentrations and the thickness of the endothelial glycocalyx layer as obtained by imaging methods. RESULTS Out of 3,454 publications, we identified 228 that met our inclusion criteria. The vast majority demonstrate an increase in plasma glycocalyx products. Sepsis and trauma are most frequently studied, and comprise approximately 40 publications. They usually report 3-4-foldt increased levels of glycocalyx degradation products, most commonly of syndecan-1. Surgery shows a variable picture. Cardiac surgery and transplantations are most likely to involve elevations of glycocalyx degradation products. Structural assessment using imaging methods show thinning of the endothelial glycocalyx layer in cardiovascular conditions and during major surgery, but thinning does not always correlate with the plasma concentrations of glycocalyx products. The few structural assessments performed do not currently support that capillary permeability is increased when the plasma levels of glycocalyx fragments in plasma are increased. CONCLUSIONS Shedding of glycocalyx components is a ubiquitous process that occurs during both acute and chronic inflammation with no sensitivity or specificity for a specific disease or condition.
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Affiliation(s)
- Robert G. Hahn
- Research UnitSödertälje Hospital Södertälje Sweden
- Karolinska Institute at Danderyds Hospital (KIDS) Stockholm Sweden
| | - Vasu Patel
- Department of Internal Medicine Northwestern Medicine McHenry Hospital McHenry IL USA
| | - Randal O. Dull
- Department of Anesthesiology, Pathology, Physiology, Surgery University of ArizonaCollege of Medicine Tucson AZ USA
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11
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Abstract
The blood-brain barrier (BBB) is a vital interface that supports normal brain functions. Endothelial cells (ECs) are the main component of the BBB and are highly specialized to govern the transfer of substances into brain. The EC lumen is enmeshed with an extracellular matrix (ECM), known as the endothelial glycocalyx layer (EGL). The lumen-facing EGL is primarily comprised of proteoglycans (PGs) and glycosaminoglycans (GAGs), which function as the first line of defense for blood-to-brain transfer of substances. Circulating factors must first penetrate the EGL before interacting with the EC. The abundance and composition of the PG and GAGs can dictate EGL function, and determine which circulating substances communicate with the ECs. The EGL can interact with circulating factors through physio-chemical interactions with the EC. Some disease states reveal a "thinning" of the EGL that may increase EC interactions with components of the systemic circulation and alter BBB function. EGL changes may also contribute to the cognitive complications of systemic diseases, such as sepsis and diabetes. For decades, researchers have measured how genetic and environmental factors influence the peripheral EGL constituents; however, much less is known about the neurovascular EGL. In this mini-review, we introduce components of the EGL and innovative ways to measure their abundance and composition that may contribute to BBB dysfunction.
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Affiliation(s)
- Aric F Logsdon
- Geriatrics Research Education and Clinical Center,
Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108,
USA
- Division of Gerontology and Geriatric Medicine,
Department of Medicine, University of Washington School of Medicine,
Seattle, WA 98159, USA
| | - Elizabeth M Rhea
- Geriatrics Research Education and Clinical Center,
Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108,
USA
- Division of Gerontology and Geriatric Medicine,
Department of Medicine, University of Washington School of Medicine,
Seattle, WA 98159, USA
| | - May Reed
- Geriatrics Research Education and Clinical Center,
Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108,
USA
- Division of Gerontology and Geriatric Medicine,
Department of Medicine, University of Washington School of Medicine,
Seattle, WA 98159, USA
| | - William A Banks
- Geriatrics Research Education and Clinical Center,
Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108,
USA
- Division of Gerontology and Geriatric Medicine,
Department of Medicine, University of Washington School of Medicine,
Seattle, WA 98159, USA
| | - Michelle A Erickson
- Geriatrics Research Education and Clinical Center,
Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108,
USA
- Division of Gerontology and Geriatric Medicine,
Department of Medicine, University of Washington School of Medicine,
Seattle, WA 98159, USA
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12
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Zhao F, Zhong L, Luo Y. Endothelial glycocalyx as an important factor in composition of blood-brain barrier. CNS Neurosci Ther 2020; 27:26-35. [PMID: 33377610 PMCID: PMC7804892 DOI: 10.1111/cns.13560] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/03/2020] [Accepted: 11/22/2020] [Indexed: 12/19/2022] Open
Abstract
The blood‐brain barrier is a dynamic and complex neurovascular unit that protects neurons from somatic circulatory factors as well as regulates the internal environmental stability of the central nervous system. Endothelial glycocalyx is a critical component of an extended neurovascular unit that influences the structure of the blood‐brain barrier and plays various physiological functions, including an important role in maintaining normal neuronal homeostasis. Specifically, glycocalyx acts in physical and charge barriers, mechanical transduction, regulation of vascular permeability, modulation of inflammatory response, and anticoagulation. Since intact glycocalyx is necessary to maintain the stability and integrity of the internal environment of the blood‐brain barrier, damage to glycocalyx can lead to the dysfunction of the blood‐brain barrier. This review discusses the role of glycocalyx in the context of the substantial literature regarding the blood‐brain barrier research, in order to provide a theoretical basis for the diagnosis and treatment of neurological diseases as well as point to new breakthroughs and innovations in glycocalyx‐dependent blood‐brain barrier function.
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Affiliation(s)
- Fangfang Zhao
- Institute of Cerebrovascular Disease Research and Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Liyuan Zhong
- Institute of Cerebrovascular Disease Research and Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Yumin Luo
- Institute of Cerebrovascular Disease Research and Department of Neurology, Xuanwu Hospital of Capital Medical University, Beijing, China.,Beijing Key Laboratory of Translational Medicine for Cerebrovascular Diseases, Beijing Geriatric Medical Research Center, Beijing, China.,Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
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Beurskens DMH, Bol ME, Delhaas T, van de Poll MCG, Reutelingsperger CPM, Nicolaes GAF, Sels JWEM. Decreased endothelial glycocalyx thickness is an early predictor of mortality in sepsis. Anaesth Intensive Care 2020; 48:221-228. [PMID: 32486831 PMCID: PMC7328096 DOI: 10.1177/0310057x20916471] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Microcirculatory alterations play an important role in the early phase of sepsis. Shedding of the endothelial glycocalyx is regarded as a central pathophysiological mechanism causing microvascular dysfunction, contributing to multiple organ failure and death in sepsis. The objective of this study was to investigate whether endothelial glycocalyx thickness at an early stage in septic patients relates to clinical outcome. We measured the perfused boundary region (PBR), which is inversely proportional to glycocalyx thickness, of sublingual microvessels (5-25 µm) using sidestream dark field imaging. The PBR in 21 patients with sepsis was measured within 24 h of admission to the intensive care unit (ICU). In addition, we determined plasma markers of microcirculatory dysfunction and studied their correlation with PBR and mortality. Endothelial glycocalyx thickness in sepsis was significantly lower for non-survivors as compared with survivors, indicated by a higher PBR of 1.97 [1.85, 2.19]µm compared with 1.76 [1.59, 1.97] µm, P=0.03. Admission PBR was associated with hospital mortality with an area under the curve of 0.778 based on the receiver operating characteristic curve. Furthermore, PBR correlated positively with angiopoietin-2 (rho=0.532, P=0.03), indicative of impaired barrier function. PBR did not correlate with Acute Physiology and Chronic Health Evaluation IV (APACHE IV), Sequential Organ Failure Assessment score (SOFA score), lactate, syndecan-1, angiopoietin-1 or heparin-binding protein. An increased PBR within the first 24 h after ICU admission is associated with mortality in sepsis. Further research should be aimed at the pathophysiological importance of glycocalyx shedding in the development of multi-organ failure and at therapies attempting to preserve glycocalyx integrity.
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Affiliation(s)
- Daniëlle MH Beurskens
- Department of Biochemistry, Maastricht University, the
Netherlands
- Cardiovascular Research Institute Maastricht, Maastricht
University, the Netherlands
| | - Martine E Bol
- Department of Intensive Care Medicine, Maastricht University
Medical Center, the Netherlands
- School of Nutrition and Translational Research in Metabolism,
Maastricht University, the Netherlands
| | - Tammo Delhaas
- Cardiovascular Research Institute Maastricht, Maastricht
University, the Netherlands
- Department of Biomedical Engineering, Maastricht University, the
Netherlands
| | - Marcel CG van de Poll
- Department of Intensive Care Medicine, Maastricht University
Medical Center, the Netherlands
- School of Nutrition and Translational Research in Metabolism,
Maastricht University, the Netherlands
- Department of Surgery, Maastricht University Medical Center, the
Netherlands
| | - Chris PM Reutelingsperger
- Department of Biochemistry, Maastricht University, the
Netherlands
- Cardiovascular Research Institute Maastricht, Maastricht
University, the Netherlands
| | - Gerry AF Nicolaes
- Department of Biochemistry, Maastricht University, the
Netherlands
- Cardiovascular Research Institute Maastricht, Maastricht
University, the Netherlands
| | - Jan-Willem EM Sels
- Department of Intensive Care Medicine, Maastricht University
Medical Center, the Netherlands
- Department of Cardiology, Maastricht University Medical Center,
the Netherlands
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Dostalova V, Astapenko D, Dostalova V Jr, Kraus J, Cerny V, Ticha A, Hyspler R, Radochova V, Paral J, Dostal P. The Effect of Fluid Loading and Hypertonic Saline Solution on Cortical Cerebral Microcirculation and Glycocalyx Integrity. J Neurosurg Anesthesiol 2019; 31:434-43. [PMID: 30015696 DOI: 10.1097/ANA.0000000000000528] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Fluid loading and hyperosmolar solutions can modify the cortical brain microcirculation and the endothelial glycocalyx (EG). This study compared the short-term effects of liberal fluid loading with a restrictive fluid intake followed by osmotherapy with hypertonic saline (HTS) on cerebral cortical microcirculation and EG integrity in a rabbit craniotomy model. METHODS The experimental rabbits were allocated randomly to receive either <2 mL/kg/h (group R, n=14) or 30 mL/kg/h (group L, n=14) of balanced isotonic fluids for 1 hour. Then, the animals were randomized to receive 5 mL/kg intravenous infusion of either 3.2% saline (group HTS, n=14) or 0.9% saline (group normal saline, n=13) in a 20-minute infusion. Microcirculation in the cerebral cortex based on sidestream dark-field imaging, a morphologic index of glycocalyx damage to sublingual and cortical brain microcirculation (the perfused boundary region), and serum syndecan-1 levels were evaluated. RESULTS Lower cortical brain perfused small vessel density (P=0.0178), perfused vessel density (P=0.0286), and total vessel density (P=0.0447) were observed in group L, compared with group R. No differences were observed between the HTS and normal saline groups after osmotherapy. Cerebral perfused boundary region values (P=0.0692) and hematocrit-corrected serum syndecan-1 levels (P=0.0324) tended to be higher in group L than in group R animals. CONCLUSIONS Liberal fluid loading was associated with altered cortical cerebral microcirculation and EG integrity parameters. The 3.2% saline treatment did not affect cortical cerebral microcirculation or EG integrity markers.
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15
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Abassi Z, Armaly Z, Heyman SN. Glycocalyx Degradation in Ischemia-Reperfusion Injury. Am J Pathol 2020; 190:752-767. [PMID: 32035883 DOI: 10.1016/j.ajpath.2019.08.019] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 07/13/2019] [Accepted: 08/20/2019] [Indexed: 02/06/2023]
Abstract
The glycocalyx is a layer coating the luminal surface of vascular endothelial cells. It is vital for endothelial function as it participates in microvascular reactivity, endothelium interaction with blood constituents, and vascular permeability. Structural and functional damage to glycocalyx occurs in various disease states. A prominent clinical situation characterized by glycocalyx derangement is ischemia-reperfusion (I/R) of the whole body as well as during selective I/R to organs such as the kidney, heart, lung, or liver. Degradation of the glycocalyx is now considered a cornerstone in I/R-related endothelial dysfunction, which further impairs local microcirculation with a feed-forward loop of organ damage, due to vasoconstriction, leukocyte adherence, and activation of the immune response. Glycocalyx damage during I/R is evidenced by rising plasma levels of its principal constituents, heparan sulfate and syndecan-1. By contrast, the concentrations of these compounds in the circulation decrease after successful protective interventions in I/R, suggesting their use as surrogate biomarkers of endothelial integrity. In light of the importance of the glycocalyx in preserving endothelial cell integrity and its involvement in pathologic conditions, several promising therapeutic strategies to restore the damaged glycocalyx and to attenuate its deleterious consequences have been suggested. This review focuses on alterations of glycocalyx during I/R injury in general (to vital organs in particular), and on maneuvers aimed at glycocalyx recovery during I/R injury.
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Affiliation(s)
- Zaid Abassi
- Department of Physiology, The Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israeli Institute of Technology, Haifa, Israel; Laboratory Medicine, Rambam Health Campus, Haifa, Israel.
| | - Zaher Armaly
- Department of Nephrology, Nazareth Hospital, Nazareth, Azrieli Faculty of Medicine-Bar Ilan University, Jerusalem, Israel
| | - Samuel N Heyman
- Department of Medicine, Hadassah Hebrew University Hospital, Mt. Scopus, Jerusalem, Israel
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16
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Butler MJ, Down CJ, Foster RR, Satchell SC. The Pathological Relevance of Increased Endothelial Glycocalyx Permeability. Am J Pathol 2020; 190:742-751. [PMID: 32035881 DOI: 10.1016/j.ajpath.2019.11.015] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 10/25/2019] [Accepted: 11/22/2019] [Indexed: 01/06/2023]
Abstract
The endothelial glycocalyx is a vital regulator of vascular permeability. Damage to this delicate layer can result in increased protein and water transit. The clinical importance of albuminuria as a predictor of kidney disease progression and vascular disease has driven research in this area. This review outlines how research to date has attempted to measure the contribution of the endothelial glycocalyx to vessel wall permeability. We discuss the evidence for the role of the endothelial glycocalyx in regulating permeability in discrete areas of the vasculature and highlight the inherent limitations of the data that have been produced to date. In particular, this review emphasizes the difficulties in interpreting urinary albumin levels in early disease models. In addition, the research that supports the view that glycocalyx damage is a key pathologic step in a diverse array of clinical conditions, including diabetic complications, sepsis, preeclampsia, and atherosclerosis, is summarized. Finally, novel methods are discussed, including an ex vivo glomerular permeability assay that enhances the understanding of permeability changes in disease.
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Affiliation(s)
- Matthew J Butler
- Bristol Renal, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom.
| | - Colin J Down
- Bristol Renal, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Rebecca R Foster
- Bristol Renal, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Simon C Satchell
- Bristol Renal, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
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17
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Hayden MR. Type 2 Diabetes Mellitus Increases The Risk of Late-Onset Alzheimer's Disease: Ultrastructural Remodeling of the Neurovascular Unit and Diabetic Gliopathy. Brain Sci 2019; 9:brainsci9100262. [PMID: 31569571 PMCID: PMC6826500 DOI: 10.3390/brainsci9100262] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 09/17/2019] [Accepted: 09/27/2019] [Indexed: 12/11/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) and late-onset Alzheimer’s disease–dementia (LOAD) are increasing in global prevalence and current predictions indicate they will only increase over the coming decades. These increases may be a result of the concurrent increases of obesity and aging. T2DM is associated with cognitive impairments and metabolic factors, which increase the cellular vulnerability to develop an increased risk of age-related LOAD. This review addresses possible mechanisms due to obesity, aging, multiple intersections between T2DM and LOAD and mechanisms for the continuum of progression. Multiple ultrastructural images in female diabetic db/db models are utilized to demonstrate marked cellular remodeling changes of mural and glia cells and provide for the discussion of functional changes in T2DM. Throughout this review multiple endeavors to demonstrate how T2DM increases the vulnerability of the brain’s neurovascular unit (NVU), neuroglia and neurons are presented. Five major intersecting links are considered: i. Aging (chronic age-related diseases); ii. metabolic (hyperglycemia advanced glycation end products and its receptor (AGE/RAGE) interactions and hyperinsulinemia-insulin resistance (a linking linchpin); iii. oxidative stress (reactive oxygen–nitrogen species); iv. inflammation (peripheral macrophage and central brain microglia); v. vascular (macrovascular accelerated atherosclerosis—vascular stiffening and microvascular NVU/neuroglial remodeling) with resulting impaired cerebral blood flow.
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Affiliation(s)
- Melvin R Hayden
- Diabetes and Cardiovascular Center, University of Missouri School of Medicine, Columbia, MO 65212, USA.
- Division of Endocrinology and Metabolism, Department of Medicine, University of Missouri, Columbia, MO 65212, USA.
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