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Zapata-Acevedo JF, Mantilla-Galindo A, Vargas-Sánchez K, González-Reyes RE. Blood-brain barrier biomarkers. Adv Clin Chem 2024; 121:1-88. [PMID: 38797540 DOI: 10.1016/bs.acc.2024.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
The blood-brain barrier (BBB) is a dynamic interface that regulates the exchange of molecules and cells between the brain parenchyma and the peripheral blood. The BBB is mainly composed of endothelial cells, astrocytes and pericytes. The integrity of this structure is essential for maintaining brain and spinal cord homeostasis and protection from injury or disease. However, in various neurological disorders, such as traumatic brain injury, Alzheimer's disease, and multiple sclerosis, the BBB can become compromised thus allowing passage of molecules and cells in and out of the central nervous system parenchyma. These agents, however, can serve as biomarkers of BBB permeability and neuronal damage, and provide valuable information for diagnosis, prognosis and treatment. Herein, we provide an overview of the BBB and changes due to aging, and summarize current knowledge on biomarkers of BBB disruption and neurodegeneration, including permeability, cellular, molecular and imaging biomarkers. We also discuss the challenges and opportunities for developing a biomarker toolkit that can reliably assess the BBB in physiologic and pathophysiologic states.
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Affiliation(s)
- Juan F Zapata-Acevedo
- Grupo de Investigación en Neurociencias, Centro de Neurociencia Neurovitae-UR, Instituto de Medicina Traslacional, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
| | - Alejandra Mantilla-Galindo
- Grupo de Investigación en Neurociencias, Centro de Neurociencia Neurovitae-UR, Instituto de Medicina Traslacional, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
| | - Karina Vargas-Sánchez
- Laboratorio de Neurofisiología Celular, Grupo de Neurociencia Traslacional, Facultad de Medicina, Universidad de los Andes, Bogotá, Colombia
| | - Rodrigo E González-Reyes
- Grupo de Investigación en Neurociencias, Centro de Neurociencia Neurovitae-UR, Instituto de Medicina Traslacional, Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia.
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Pathogenesis of sepsis-associated encephalopathy: more than blood-brain barrier dysfunction. Mol Biol Rep 2022; 49:10091-10099. [PMID: 35639274 DOI: 10.1007/s11033-022-07592-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 05/11/2022] [Indexed: 12/19/2022]
Abstract
Sepsis-associated encephalopathy is a common neurological complication of sepsis and is responsible for higher mortality and poorer long-term outcomes in septic patients. Sepsis-associated encephalopathy symptoms can range from mild delirium to deep coma, which occurs in up to 70% of patients in intensive care units. The pathological changes in the brain associated with sepsis include cerebral ischaemia, cerebral haemorrhage, abscess and progressive multifocal necrotic leukoencephalopathy. Several mechanisms are involved in the pathogenesis of sepsis-associated encephalopathy, such as blood-brain barrier dysfunction, cerebral blood flow impairment, glial cell activation, leukocyte transmigration, and neurotransmitter disturbances. These events are interrelated and influence each other, therefore they do not act as independent factors. This review is focused on new evidence showing the pathological process of sepsis-associated encephalopathy.
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Persistent hyperammonia and altered concentrations of urea cycle metabolites in a 5-day swine experiment of sepsis. Sci Rep 2021; 11:18430. [PMID: 34531431 PMCID: PMC8445921 DOI: 10.1038/s41598-021-97855-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 08/24/2021] [Indexed: 01/20/2023] Open
Abstract
We measured plasma and cerebrospinal fluid (CSF) metabolite concentrations in a 5-day porcine sepsis model of fecal peritonitis. The objectives were: (i) to verify whether the expected pathways that had emerged in previous studies pertain only to the early inflammatory response or persist for the subsequent days; (ii) to identify metabolic derangements that arise later; (iii) to verify whether CSF metabolite concentrations were altered and if these alterations were similar to those in the blood or delayed. We observed an early response to inflammation and cytokine storms with alterations in lipid and glucose metabolism. The arginine/asymmetric dimethylarginine (ADMA) and phenylalanine/tyrosine balances changed 24 h after resuscitation in plasma, and later in CSF. There was a rise in ammonia concentration, with altered concentrations of metabolites in the urea cycle. Whether persistent derangement of these pathways have a role not only on short-term outcomes but also on longer-term comorbidities, such as septic encephalopathy, should be addressed in further studies.
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Atterton B, Paulino MC, Povoa P, Martin-Loeches I. Sepsis Associated Delirium. ACTA ACUST UNITED AC 2020; 56:medicina56050240. [PMID: 32443606 PMCID: PMC7279289 DOI: 10.3390/medicina56050240] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/13/2020] [Accepted: 05/14/2020] [Indexed: 01/04/2023]
Abstract
Sepsis is a potentially life-threatening condition caused by a systemic dysregulated host response to infection. The brain is particularly susceptible to the effects of sepsis with clinical manifestations ranging from mild confusion to a deep comatose state. Sepsis-associated delirium (SAD) is a cerebral manifestation commonly occurring in patients with sepsis and is thought to occur due to a combination of neuroinflammation and disturbances in cerebral perfusion, the blood brain barrier (BBB) and neurotransmission. The neurological impairment associated with SAD can persist for months or even longer, after the initial septic episode has subsided which may impair the rehabilitation potential of sepsis survivors. Early identification and treatment of the underlying sepsis is key in the management of SAD as once present it can be difficult to control. Through the regular use of validated screening tools for delirium, cases of SAD can be identified early; this allows potentially aggravating factors to be addressed promptly. The usefulness of biomarkers, neuroimaging and electroencephalopathy (EEG) in the diagnosis of SAD remains controversial. The Society of Critical Care Medicine (SCCM) guidelines advise against the use of medications to treat delirium unless distressing symptoms are present or it is hindering the patient’s ability to wean from organ support.
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Affiliation(s)
- Ben Atterton
- Department of Intensive Care Medicine, Multidisciplinary Intensive Care Research Organization (MICRO), St. James’s Hospital, St. James Street, Dublin 8, Dublin, D08 NHY1, Ireland;
| | - Maria Carolina Paulino
- Polyvalent Intensive Care Unit, São Francisco Xavier Hospital, Centro Hospitalar de Lisboa Ocidental, 1449-005 Lisbon, Portugal; (M.C.P.); (P.P.)
| | - Pedro Povoa
- Polyvalent Intensive Care Unit, São Francisco Xavier Hospital, Centro Hospitalar de Lisboa Ocidental, 1449-005 Lisbon, Portugal; (M.C.P.); (P.P.)
- NOVA Medical School, CHRC, New University of Lisbon, 1099-085 Lisbon, Portugal
- Center for Clinical Epidemiology and Research Unit of Clinical Epidemiology, OUH Odense University Hospital, 5000 Odense, Denmark
| | - Ignacio Martin-Loeches
- Department of Intensive Care Medicine, Multidisciplinary Intensive Care Research Organization (MICRO), St. James’s Hospital, St. James Street, Dublin 8, Dublin, D08 NHY1, Ireland;
- Hospital Clinic, IDIBAPS, Universidad de Barcelona, Ciberes, 08036 Barcelona, Spain
- Correspondence:
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Dahl RH, Berg RMG, Taudorf S, Bailey DM, Lundby C, Christensen M, Larsen FS, Møller K. Transcerebral exchange kinetics of large neutral amino acids during acute inspiratory hypoxia in humans. Scandinavian Journal of Clinical and Laboratory Investigation 2019; 79:595-600. [PMID: 31657241 DOI: 10.1080/00365513.2019.1683762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Hypoxaemia is present in many critically ill patients, and may contribute to encephalopathy. Changes in the passage of large neutral amino acids (LNAAs) across the blood-brain barrier (BBB) with an increased cerebral influx of aromatic amino acids into the brain may concurrently be present and also contribute to encephalopathy, but it has not been established whether hypoxaemia per se may trigger such changes. We measured cerebral blood flow (CBF) in 11 healthy men using the Kety-Schmidt technique and obtained paired arterial and jugular-venous blood samples for the determination of LNAAs by high performance liquid chromatography at baseline and after 9 hours of poikilocapnic normobaric hypoxia (12% O2). Transcerebral net exchange was determined by the Fick principle, and transport of LNAAs across the BBB was determined mathematically. Hypoxia increased both the systemic and corresponding cerebral delivery of the aromatic amino acid phenylalanine, and the branched-chain amino acids leucine and isoleucine. Despite this, the transcerebral net exchange values and mathematically derived brain extracellular concentrations for all LNAAs were unaffected. In conclusion, the observed changes in circulating LNAAs triggered by hypoxaemia do not affect the transcerebral exchange kinetics of LNAAs to such an extent that their brain extracellular concentrations are affected.
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Affiliation(s)
- Rasmus H Dahl
- Department of Neuroanaesthesiology, Rigshospitalet, Copenhagen, Denmark
| | - Ronan M G Berg
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontyprid, UK
| | - Sarah Taudorf
- Department of Neurology 2082, University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontyprid, UK
| | - Carsten Lundby
- Centre for Physical Activity Research, Rigshospitalet, Copenhagen, Denmark
| | - Mette Christensen
- Department of Clinical Genetics, Rigshospitalet, Copenhagen, Denmark
| | - Fin S Larsen
- Department of Hepatology, Rigshospitalet, Copenhagen, Denmark
| | - Kirsten Møller
- Department of Neuroanaesthesiology, Rigshospitalet, Copenhagen, Denmark
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Qi Z, Liu KJ. The interaction of zinc and the blood-brain barrier under physiological and ischemic conditions. Toxicol Appl Pharmacol 2019; 364:114-119. [PMID: 30594689 PMCID: PMC6331270 DOI: 10.1016/j.taap.2018.12.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 12/02/2018] [Accepted: 12/25/2018] [Indexed: 12/30/2022]
Abstract
Zinc is the second most abundant metal in human and serves as an essential trace element in the body. During the past decades, zinc has been found to play important roles in central nervous system, such as the development of neurons and synaptic activities. An imbalance of zinc is associated with brain diseases. The blood-brain barrier (BBB) maintains the homeostasis of the microenvironment, regulating the balance of zinc in the brain. A compromised BBB is the main cause of severe complications in cerebral ischemic patients, such as hemorrhage transformation, inflammation and edema. Recent studies reported that zinc in the brain may be a potential target for integrative protection against ischemic brain injury. Although zinc has long been regarded as important transmitters in central nervous system, the critical role of zinc dyshomeostasis in damage to the BBB has not been fully recognized. In this review, we summarize the role of the BBB in regulating homeostasis of zinc in physiological conditions and the effects of changes in zinc levels on the permeability of the BBB in cerebral ischemia. The integrity of BBB maintains the homeostasis of zinc in pathological conditions, while the balance of zinc in the brain and the circulation maintains the normal function of the BBB. Interrupting the zinc/BBB system will disturb the microenvironment in the brain, leading to pathological diseases. In stroke patients, zinc may serve as a potential target for protecting the BBB and reducing hemorrhage transformation, inflammation and edema.
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Affiliation(s)
- Zhifeng Qi
- Cerebrovascular Diseases Research Institute, Xuanwu Hospital of Capital Medical University, Beijing, China
| | - Ke Jian Liu
- Cerebrovascular Diseases Research Institute, Xuanwu Hospital of Capital Medical University, Beijing, China; Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
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Abstract
PURPOSE OF THE REVIEW To discuss the diagnostic approach to patients with septic encephalopathy as well as the need for specific neuro-monitoring and the perspectives on future therapeutic approaches in this setting. RECENT FINDINGS Most of data-concern experimental studies evaluating the pathophysiology of septic encephalopathy. A combination of neurodegenerative pathways with neurovascular injury is the cornerstone for the development of such complication and the long-term neurological sequelae among survivors. Septic encephalopathy is a common complication in septic patients. Clinical presentation may range from mild confusion and disorientation to convulsions and deep coma. The diagnosis of septic encephalopathy is made difficult by the lack of any specific clinical and non-clinical feature, in particular among sedated patients in whom neurological examination is unreliable. In spite of the high mortality rate associated with this condition, there is no prophylactic or targeted therapy to reduce or minimize brain damage in septic patients and clinical management is limited to the treatment of the underlying infection.
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