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Lochhead JJ, Ronaldson PT, Davis TP. The role of oxidative stress in blood-brain barrier disruption during ischemic stroke: Antioxidants in clinical trials. Biochem Pharmacol 2024:116186. [PMID: 38561092 DOI: 10.1016/j.bcp.2024.116186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/19/2024] [Accepted: 03/29/2024] [Indexed: 04/04/2024]
Abstract
Ischemic stroke is one of the leading causes of death and disability. Occlusion and reperfusion of cerebral blood vessels (i.e., ischemia/reperfusion (I/R) injury) generates reactive oxygen species (ROS) that contribute to brain cell death and dysfunction of the blood-brain barrier (BBB) via oxidative stress. BBB disruption influences the pathogenesis of ischemic stroke by contributing to cerebral edema, hemorrhagic transformation, and extravasation of circulating neurotoxic proteins. An improved understanding of mechanisms for ROS-associated alterations in BBB function during ischemia/reperfusion (I/R) injury can lead to improved treatment paradigms for ischemic stroke. Unfortunately, progress in developing ROS targeted therapeutics that are effective for stroke treatment has been slow. Here, we review how ROS are produced in response to I/R injury, their effects on BBB integrity (i.e., tight junction protein complexes, transporters), and the utilization of antioxidant treatments in ischemic stroke clinical trials. Overall, knowledge in this area provides a strong translational framework for discovery of novel drugs for stroke and/or improved strategies to mitigate I/R injury in stroke patients.
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Affiliation(s)
- Jeffrey J Lochhead
- Department of Pharmacology, University of Arizona College of Medicine, Tucson, AZ 85724, USA.
| | - Patrick T Ronaldson
- Department of Pharmacology, University of Arizona College of Medicine, Tucson, AZ 85724, USA
| | - Thomas P Davis
- Department of Pharmacology, University of Arizona College of Medicine, Tucson, AZ 85724, USA
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2
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Santiago HP, Leite LHR, Lima PMA, Fóscolo DRC, Natali AJ, Prímola-Gomes TN, Szawka RE, Coimbra CC. Effects of physical training on hypothalamic neuronal activation and expressions of vasopressin and oxytocin in SHR after running until fatigue. Pflugers Arch 2024; 476:365-377. [PMID: 38308122 DOI: 10.1007/s00424-024-02916-1] [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] [Received: 11/14/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/04/2024]
Abstract
To assess the influence of physical training on neuronal activation and hypothalamic expression of vasopressin and oxytocin in spontaneously hypertensive rats (SHR), untrained and trained normotensive rats and SHR were submitted to running until fatigue while internal body and tail temperatures were recorded. Hypothalamic c-Fos expression was evaluated in thermoregulatory centers such as the median preoptic nucleus (MnPO), medial preoptic nucleus (mPOA), paraventricular nucleus of the hypothalamus (PVN), and supraoptic nucleus (SON). The PVN and the SON were also investigated for vasopressin and oxytocin expressions. Although exercise training improved the workload performed by the animals, it was reduced in SHR and followed by increased internal body temperature due to tail vasodilation deficit. Physical training enhanced c-Fos expression in the MnPO, mPOA, and PVN of both strains, and these responses were attenuated in SHR. Vasopressin immunoreactivity in the PVN was also increased by physical training to a lesser extent in SHR. The already-reduced oxytocin expression in the PVN of SHR was increased in response to physical training. Within the SON, neuronal activation and the expressions of vasopressin and oxytocin were reduced by hypertension and unaffected by physical training. The data indicate that physical training counterbalances in part the negative effect of hypertension on hypothalamic neuronal activation elicited by exercise, as well as on the expression of vasopressin and oxytocin. These hypertension features seem to negatively influence the workload performed by SHR due to the hyperthermia derived from the inability of physical training to improve heat dissipation through skin vasodilation.
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Affiliation(s)
- Henrique P Santiago
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Laura H R Leite
- Departamento de Biofísica e Fisiologia, Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil
| | - Paulo M A Lima
- Núcleo de Pesquisa da Faculdade de Medicina da Universidade de Rio Verde, Universidade de Rio Verde, Campus Goiânia, Goiânia, Brazil
| | - Daniela R C Fóscolo
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Antônio José Natali
- Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | | | - Raphael E Szawka
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Cândido C Coimbra
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil.
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3
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Levanovich PE, Daugherty AM, Komnenov D, Rossi NF. Dietary fructose and high salt in young male Sprague Dawley rats induces salt-sensitive changes in renal function in later life. Physiol Rep 2022; 10:e15456. [PMID: 36117446 PMCID: PMC9483717 DOI: 10.14814/phy2.15456] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 08/20/2022] [Indexed: 06/15/2023] Open
Abstract
Dietary fructose and salt are associated with hypertension and renal disease. Dietary input during critical postnatal periods may impact pathophysiology in maturity. The highest consumption of fructose occurs during adolescence. We hypothesized that a diet high in fructose with or without high salt in young male Sprague Dawley rats will lead to salt-sensitive hypertension, albuminuria, and decreased renal function in maturity. Four groups were studied from age 5 weeks: 20% glucose + 0.4% salt (GCS-GCS) or 20% fructose + 4% salt throughout (FHS-FHS). Two groups received 20% fructose + 0.4% salt or 20% fructose + 4% salt for 3 weeks (Phase I) followed by 20% glucose + 0.4% salt (Phase II). In Phase III (age 13-15 weeks), these two groups were challenged with 20% glucose + 4% salt, (FCS-GHS) and (FHS-GHS), respectively. Each group fed fructose in Phase I exhibited significantly higher MAP than GCS-GCS in Phase III. Net sodium balance, unadjusted, or adjusted for caloric intake and urine flow rate, and cumulative sodium balance were positive in FHS during Phase I and were significantly higher in FCS-GHS, FHS-GHS, and FHS-FHS vs GCS-GCS during Phase III. All three groups fed fructose during Phase I displayed significantly elevated albuminuria. GFR was significantly lower in FHS-FHS vs GCS-GCS at maturity. Qualitative histology showed mesangial expansion and hypercellularity in FHS-FHS rats. Thus, fructose ingestion during a critical period in rats, analogous to human preadolescence and adolescence, results in salt-sensitive hypertension and albuminuria in maturity. Prolonged dietary fructose and salt ingestion lead to a decline in renal function with evidence suggestive of mesangial hypercellularity.
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Affiliation(s)
| | - Ana M. Daugherty
- Department of Psychology and Institute of GerontologyWayne State UniversityDetroitMichiganUSA
| | - Dragana Komnenov
- Department of Internal MedicineWayne State UniversityDetroitMichiganUSA
| | - Noreen F. Rossi
- Department of PhysiologyWayne State UniversityDetroitMichiganUSA
- Department of Internal MedicineWayne State UniversityDetroitMichiganUSA
- John D. Dingell VA Medical CenterDetroitMichiganUSA
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4
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Blood-Brain Barrier Transporters: Opportunities for Therapeutic Development in Ischemic Stroke. Int J Mol Sci 2022; 23:ijms23031898. [PMID: 35163820 PMCID: PMC8836701 DOI: 10.3390/ijms23031898] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/02/2022] [Accepted: 02/04/2022] [Indexed: 12/20/2022] Open
Abstract
Globally, stroke is a leading cause of death and long-term disability. Over the past decades, several efforts have attempted to discover new drugs or repurpose existing therapeutics to promote post-stroke neurological recovery. Preclinical stroke studies have reported successes in identifying novel neuroprotective agents; however, none of these compounds have advanced beyond a phase III clinical trial. One reason for these failures is the lack of consideration of blood-brain barrier (BBB) transport mechanisms that can enable these drugs to achieve efficacious concentrations in ischemic brain tissue. Despite the knowledge that drugs with neuroprotective properties (i.e., statins, memantine, metformin) are substrates for endogenous BBB transporters, preclinical stroke research has not extensively studied the role of transporters in central nervous system (CNS) drug delivery. Here, we review current knowledge on specific BBB uptake transporters (i.e., organic anion transporting polypeptides (OATPs in humans; Oatps in rodents); organic cation transporters (OCTs in humans; Octs in rodents) that can be targeted for improved neuroprotective drug delivery. Additionally, we provide state-of-the-art perspectives on how transporter pharmacology can be integrated into preclinical stroke research. Specifically, we discuss the utility of in vivo stroke models to transporter studies and considerations (i.e., species selection, co-morbid conditions) that will optimize the translational success of stroke pharmacotherapeutic experiments.
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Fragas MG, Cândido VB, Davanzo GG, Rocha-Santos C, Ceroni A, Michelini LC. Transcytosis within PVN capillaries: a mechanism determining both hypertension-induced blood-brain barrier dysfunction and exercise-induced correction. Am J Physiol Regul Integr Comp Physiol 2021; 321:R732-R741. [PMID: 34549626 DOI: 10.1152/ajpregu.00154.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/17/2021] [Indexed: 11/22/2022]
Abstract
Although hypertension disrupts the blood-brain barrier (BBB) integrity within the paraventricular nucleus of hypothalamus (PVN) and increases the leakage into the brain parenchyma, exercise training (T) was shown to correct it. Since there is scarce and contradictory information on the mechanism(s) determining hypertension-induced BBB deficit and nothing is known about T-induced improvement, we sought to evaluate the paracellular and transcellular transport across the BBB within the PVN in both conditions. Spontaneously hypertensive rats (SHR) and WKY submitted to 4-wk aerobic T or sedentary (S) protocol were chronically catheterized for hemodynamic recordings at rest and intra-arterial administration of dyes (Rhodamine-dextran 70 kDa + FITC-dextran 10 kDa). Brains were harvesting for FITC leakage examination, qPCR evaluation of different BBB constituents and protein expression of caveolin-1 and claudin-5, the main markers of transcytosis and paracellular transport, respectively. Hypertension was characterized by increased arterial pressure and heart rate, augmented sympathetic modulation of heart and vessels, and reduced cardiac parasympathetic control, marked FITC extravasation into the PVN which was accompanied by increased caveolin-1 gene and protein expression, without changes in claudin-5 and others tight junctions' components. SHR-T vs. SHR-S showed a partial pressure reduction, resting bradycardia, improvement of autonomic control of the circulation simultaneously with correction of both FITC leakage and caveolin-1 expression; there was a significant increase in claudin-5 expression. Caveolin-1 content was strongly correlated with improved autonomic control after exercise. Data indicated that within the PVN the transcytosis is the main mechanism governing both hypertension-induced BBB leakage, as well as the exercise-induced correction.
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Affiliation(s)
- Matheus Garcia Fragas
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, São Paulo, Brazil
| | - Vanessa Brito Cândido
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, São Paulo, Brazil
| | - Gustavo Gastão Davanzo
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, São Paulo, Brazil
| | - Carla Rocha-Santos
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, São Paulo, Brazil
| | - Alexandre Ceroni
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, São Paulo, Brazil
| | - Lisete C Michelini
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, São Paulo, Brazil
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6
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Rezende LMTD, Soares LL, Drummond FR, Suarez PZ, Leite L, Rodrigues JA, Leal T, Favarato L, Reis ECC, Favarato E, Carneiro M, Natali AJ, Coimbra C, Gomes TP. Is the Wistar Rat a more Suitable Normotensive Control for SHR to Test Blood Pressure and Cardiac Structure and Function? INTERNATIONAL JOURNAL OF CARDIOVASCULAR SCIENCES 2021. [DOI: 10.36660/ijcs.20200367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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7
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Nian K, Harding IC, Herman IM, Ebong EE. Blood-Brain Barrier Damage in Ischemic Stroke and Its Regulation by Endothelial Mechanotransduction. Front Physiol 2020; 11:605398. [PMID: 33424628 PMCID: PMC7793645 DOI: 10.3389/fphys.2020.605398] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 11/27/2020] [Indexed: 12/21/2022] Open
Abstract
Ischemic stroke, a major cause of mortality in the United States, often contributes to disruption of the blood-brain barrier (BBB). The BBB along with its supportive cells, collectively referred to as the “neurovascular unit,” is the brain’s multicellular microvasculature that bi-directionally regulates the transport of blood, ions, oxygen, and cells from the circulation into the brain. It is thus vital for the maintenance of central nervous system homeostasis. BBB disruption, which is associated with the altered expression of tight junction proteins and BBB transporters, is believed to exacerbate brain injury caused by ischemic stroke and limits the therapeutic potential of current clinical therapies, such as recombinant tissue plasminogen activator. Accumulating evidence suggests that endothelial mechanobiology, the conversion of mechanical forces into biochemical signals, helps regulate function of the peripheral vasculature and may similarly maintain BBB integrity. For example, the endothelial glycocalyx (GCX), a glycoprotein-proteoglycan layer extending into the lumen of bloods vessel, is abundantly expressed on endothelial cells of the BBB and has been shown to regulate BBB permeability. In this review, we will focus on our understanding of the mechanisms underlying BBB damage after ischemic stroke, highlighting current and potential future novel pharmacological strategies for BBB protection and recovery. Finally, we will address the current knowledge of endothelial mechanotransduction in BBB maintenance, specifically focusing on a potential role of the endothelial GCX.
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Affiliation(s)
- Keqing Nian
- Department of Bioengineering, Northeastern University, Boston, MA, United States
| | - Ian C Harding
- Department of Bioengineering, Northeastern University, Boston, MA, United States
| | - Ira M Herman
- Department of Development, Molecular, and Chemical Biology, Tufts Sackler School of Graduate Biomedical Sciences, Boston, MA, United States.,Center for Innovations in Wound Healing Research, Tufts University School of Medicine, Boston, MA, United States
| | - Eno E Ebong
- Department of Bioengineering, Northeastern University, Boston, MA, United States.,Department of Chemical Engineering, Northeastern University, Boston, MA, United States.,Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, United States
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8
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Drummond LR, Campos HO, de Andrade Lima PM, da Fonseca CG, Kunstetter AC, Rodrigues QT, Szawka RE, Natali AJ, Prímola-Gomes TN, Wanner SP, Coimbra CC. Impaired thermoregulation in spontaneously hypertensive rats during physical exercise is related to reduced hypothalamic neuronal activation. Pflugers Arch 2020; 472:1757-1768. [PMID: 33040159 DOI: 10.1007/s00424-020-02474-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 09/05/2020] [Accepted: 10/06/2020] [Indexed: 12/25/2022]
Abstract
This study aimed to evaluate the physical exercise-induced neuronal activation in brain nuclei controlling thermoregulatory responses in hypertensive and normotensive rats. Sixteen-week-old male normotensive Wistar rats (NWRs) and spontaneously hypertensive rats (SHRs) were implanted with an abdominal temperature sensor. After recovery, the animals were subjected to a constant-speed treadmill running (at 60% of the maximum aerobic speed) for 30 min at 25 °C. Core (Tcore) and tail-skin (Tskin) temperatures were measured every minute during exercise. Ninety minutes after the exercise, the rats were euthanized, and their brains were collected to determine the c-Fos protein expression in the following areas that modulate thermoregulatory responses: medial preoptic area (mPOA), paraventricular hypothalamic nucleus (PVN), and supraoptic nucleus (SON). During treadmill running, the SHR group exhibited a greater increase in Tcore and an augmented threshold for cutaneous heat loss relative to the NWR group. In addition, the SHRs showed reduced neuronal activation in the mPOA (< 49.7%) and PVN (< 44.2%), but not in the SON. The lower exercise-induced activation in the mPOA and PVN in hypertensive rats was strongly related to the delayed onset of cutaneous heat loss. We conclude that the enhanced exercise-induced hyperthermia in hypertensive rats can be partially explained by a delayed cutaneous heat loss, which is, in turn, associated with reduced activation of brain areas modulating thermoregulatory responses.
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Affiliation(s)
- Lucas Rios Drummond
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627., Belo Horizonte, MG, 31270-901, Brazil.
| | - Helton Oliveira Campos
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627., Belo Horizonte, MG, 31270-901, Brazil
| | - Paulo Marcelo de Andrade Lima
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627., Belo Horizonte, MG, 31270-901, Brazil
| | - Cletiana Gonçalves da Fonseca
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ana Cançado Kunstetter
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Quezia Teixeira Rodrigues
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627., Belo Horizonte, MG, 31270-901, Brazil
| | - Raphael Escorsim Szawka
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627., Belo Horizonte, MG, 31270-901, Brazil
| | - Antônio José Natali
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Thales Nicolau Prímola-Gomes
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Samuel Penna Wanner
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Cândido Celso Coimbra
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627., Belo Horizonte, MG, 31270-901, Brazil
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Drummond LR, Kunstetter AC, Campos HO, Vaz FF, Drummond FR, Andrade AG, Coimbra CC, Natali AJ, Wanner SP, Prímola-Gomes TN. Spontaneously hypertensive rats have greater impairments in regulating abdominal temperature than brain cortex temperature following physical exercise. J Therm Biol 2019; 83:30-36. [DOI: 10.1016/j.jtherbio.2019.04.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/16/2019] [Accepted: 04/18/2019] [Indexed: 12/11/2022]
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10
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Koundal S, Liu X, Sanggaard S, Mortensen K, Wardlaw J, Nedergaard M, Benveniste H, Lee H. Brain Morphometry and Longitudinal Relaxation Time of Spontaneously Hypertensive Rats (SHRs) in Early and Intermediate Stages of Hypertension Investigated by 3D VFA-SPGR MRI. Neuroscience 2019; 404:14-26. [PMID: 30690138 DOI: 10.1016/j.neuroscience.2019.01.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 01/15/2019] [Accepted: 01/18/2019] [Indexed: 02/03/2023]
Abstract
Cerebral small vessel disease(s) (SVD) results from pathological changes of the small blood vessels in the brain and is common in older people. The diagnostic features by which SVD manifests in brain includes white matter hyperintensities, lacunes, dilated perivascular spaces, microbleeds, and atrophy. In the present study, we use in vivo magnetic resonance imaging (MRI) to characterize brain morphometry and longitudinal relaxation time (T1) of spontaneously hypertensive rats (SHRs) to study the contribution of chronic hypertension to SVD relevant pathology. Male SHR and Wistar-Kyoto (WKY) rats underwent 3D variable flip angle spoiled gradient echo brain MRI at 9.4 T at early (seven weeks old) and established (19 weeks old) stages of hypertension. The derived proton density weighted and T1 images were utilized for morphometry and to characterize T1 properties in gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF). Custom tissue probability maps were constructed for accurate computerized whole brain tissue segmentations and voxel-wise analyses. Characteristic morphological differences between the two strains included enlarged ventricles, smaller corpus callosum (CC) volumes and general 'thinning' of CC in SHR compared to WKY rats at both age groups. While we did not observe parenchymal T1 differences, the T1 of CSF was elevated in SHR compared to controls. Collectively these findings indicate that SHRs develop WM atrophy which is a clinically robust MRI biomarker associated with WM degeneration.
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Affiliation(s)
- Sunil Koundal
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, United States of America
| | - Xiaodan Liu
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, United States of America
| | - Simon Sanggaard
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, United States of America
| | - Kristian Mortensen
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Joanna Wardlaw
- Center for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK; UK Dementia Research Institute at The University of Edinburgh, The University of Edinburgh, Edinburgh, UK; Row Fogo Centre for Research into Ageing and the Brain, The University of Edinburgh, Edinburgh, UK
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Division of Glia Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, NY, USA
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, United States of America
| | - Hedok Lee
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, United States of America.
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Hong XY, Hong X, Gu WW, Lin J, Yin WT. Cardioprotection and improvement in endothelial-dependent vasodilation during late-phase of whole body hypoxic preconditioning in spontaneously hypertensive rats via VEGF and endothelin-1. Eur J Pharmacol 2018; 842:79-88. [PMID: 30401629 DOI: 10.1016/j.ejphar.2018.10.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 10/17/2018] [Accepted: 10/24/2018] [Indexed: 12/13/2022]
Abstract
The present study was designed to investigate the effect of late phase of whole body hypoxic preconditioning on endothelial-dependent vasorelaxation and cardioprotection from ischemia-reperfusion injury in spontaneously hypertensive rats (SHR). Hypoxic preconditioning was performed by subjecting rats to four episodes of alternate exposure to low O2 (8%) and normal air O2 of 10 min each. After 24 h, the mesenteric arteries and hearts were isolated to determine the vascular function and cardioprotection from ischemia-reperfusion (I/R) injury on the Langendorff apparatus. There was a significant impairment in acetylcholine-induced relaxation in norepinephrine precontracted arteries (endothelium-dependent function) and increase in I/R-induced myocardial injury in SHR in comparison to Wistar Kyoto rats (WKY). However, hypoxic preconditioning significantly restored endothelium-dependent relaxation in SHR and attenuated I/R injury in both SHR and WKY. Hypoxic preconditioning also led to an increase in the levels of endothelin-1 (not endothelin-2 or -3), vascular endothelial growth factor-A (VEGF-A) and HIF-1α levels. Pretreatment with bevacizumab (anti-VEGF-A) and bosentan (endothelin receptor blocker) significantly attenuated hypoxic preconditioning-induced restoration of endothelium-dependent relaxation and cardioprotection from I/R injury. These interventions also attenuated the levels of VEGF-A and HIF-1α without modulating the endothelin-1 levels. It may be concluded that an increase in the endothelin-1 levels with a subsequent increase in HIF-1α and VEGF expression may possibly contribute in improving endothelium-dependent vasorelaxation and protecting hearts from I/R injury in SHR during late phase of whole body hypoxic preconditioning.
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Affiliation(s)
- Xing-Yu Hong
- Department of Vascular Surgery, China-Japan Union Hospital of JiLin University, ChangChun 130031, China.
| | - Xin Hong
- Department of Vascular Surgery, China-Japan Union Hospital of JiLin University, ChangChun 130031, China.
| | - Wei-Wei Gu
- Department of Hepatopancreatobility Surgery, China-Japan Union Hospital of JiLin University, ChangChun 130031, China.
| | - Jie Lin
- Department of Vascular Surgery, China-Japan Union Hospital of JiLin University, ChangChun 130031, China.
| | - Wei-Tian Yin
- Department of Hand Surgery, China-Japan Union Hospital of JiLin University, ChangChun 130031, China.
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12
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Naessens DMP, de Vos J, VanBavel E, Bakker ENTP. Blood-brain and blood-cerebrospinal fluid barrier permeability in spontaneously hypertensive rats. Fluids Barriers CNS 2018; 15:26. [PMID: 30244677 PMCID: PMC6151927 DOI: 10.1186/s12987-018-0112-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 08/23/2018] [Indexed: 12/04/2022] Open
Abstract
Background Hypertension is an important risk factor for cerebrovascular disease, including stroke and dementia. Both in humans and animal models of hypertension, neuropathological features such as brain atrophy and oedema have been reported. We hypothesised that cerebrovascular damage resulting from chronic hypertension would manifest itself in a more permeable blood–brain barrier and blood–cerebrospinal fluid barrier. In addition, more leaky barriers could potentially contribute to an enhanced interstitial fluid and cerebrospinal fluid formation, which could, in turn, lead to an elevated intracranial pressure. Methods To study this, we monitored intracranial pressure and estimated the cerebrospinal fluid production rate in spontaneously hypertensive (SHR) and normotensive rats (Wistar Kyoto, WKY) at 10 months of age. Blood–brain barrier and blood–cerebrospinal fluid barrier integrity was determined by measuring the leakage of fluorescein from the circulation into the brain and cerebrospinal fluid compartment. Prior to sacrifice, a fluorescently labelled lectin was injected into the bloodstream to visualise the vasculature and subsequently study a number of specific vascular characteristics in six different brain regions. Results Blood and brain fluorescein levels were not different between the two strains. However, cerebrospinal fluid fluorescein levels were significantly lower in SHR. This could not be explained by a difference in cerebrospinal fluid turnover, as cerebrospinal fluid production rates were similar in SHR and WKY, but may relate to a larger ventricular volume in the hypertensive strain. Also, intracranial pressure was not different between SHR and WKY. Morphometric analysis of capillary volume fraction, number of branches, capillary diameter, and total length did not reveal differences between SHR and WKY. Conclusion In conclusion, we found no evidence for blood–brain barrier or blood–cerebrospinal fluid barrier leakage to a small solute, fluorescein, in rats with established hypertension. Electronic supplementary material The online version of this article (10.1186/s12987-018-0112-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daphne M P Naessens
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Judith de Vos
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Ed VanBavel
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Erik N T P Bakker
- Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
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13
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da Fonseca SF, Mendonça VA, Silva SB, Domingues TE, Melo DS, Martins JB, Pires W, Santos CFF, de Fátima Pereira W, Leite LHR, Coimbra CC, Leite HR, Lacerda ACR. Central cholinergic activation induces greater thermoregulatory and cardiovascular responses in spontaneously hypertensive than in normotensive rats. J Therm Biol 2018; 77:86-95. [PMID: 30196904 DOI: 10.1016/j.jtherbio.2018.08.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 08/15/2018] [Accepted: 08/18/2018] [Indexed: 10/28/2022]
Abstract
There is evidence that central cholinergic stimulation increases heat dissipation in normotensive rats besides causing changes on the cardiovascular system via modulation of baroreceptors activity. However, the contribution of the central cholinergic system on thermoregulatory responses and its relationship with cardiovascular adjustments in spontaneously hypertensive rats (SHRs), an animal model of reduced baroreceptor sensitivity and thermoregulatory deficit, has not been completely clarified. Therefore, the aim of this study was to verify the involvement of the central cholinergic system in cardiovascular and thermoregulatory adjustments in SHRs. Male Wistar rats (n = 17) and SHRs (n = 17) were implanted with an intracerebroventricular cannula for injections of 2 µL of physostigmine (phy) or saline solution. Tail temperature (Ttail), internal body temperature (Tint), systolic arterial pressure (SAP), heart rate (HR) and metabolic rate were registered during 60 min while the animals remained at rest after randomly receiving the injections. The variability of the SAP and the HR was estimated by the fast Fourier transform. Phy treatment began a succession of cardiovascular and thermoregulatory responses that resulted in increased SAP, reduced HR and increased Ttail in both Wistar and SHRs groups. The magnitude of these effects seems to be more intense in SHRs, since the improvement of heat dissipation reflected in Tint. Taken together, these results provide evidence that hypertensive rats present greater cardiovascular and thermoregulatory responses than normotensive rats after central cholinergic stimulation.
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Affiliation(s)
- Sueli Ferreira da Fonseca
- Centro Integrado de Pós-Graduação e Pesquisa em Saúde (CIPq-Saúde), Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, Minas Gerais, Brazil; Programa Multicêntrico de Pós-Graduação em Ciências Fisiológicas (PMPGCF), Sociedade Brasileira de Fisiologia (SBFis), Brazil
| | - Vanessa Amaral Mendonça
- Centro Integrado de Pós-Graduação e Pesquisa em Saúde (CIPq-Saúde), Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, Minas Gerais, Brazil; Programa Multicêntrico de Pós-Graduação em Ciências Fisiológicas (PMPGCF), Sociedade Brasileira de Fisiologia (SBFis), Brazil
| | - Sara Barros Silva
- Centro Integrado de Pós-Graduação e Pesquisa em Saúde (CIPq-Saúde), Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, Minas Gerais, Brazil
| | - Talita Emanuela Domingues
- Centro Integrado de Pós-Graduação e Pesquisa em Saúde (CIPq-Saúde), Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, Minas Gerais, Brazil; Programa Multicêntrico de Pós-Graduação em Ciências Fisiológicas (PMPGCF), Sociedade Brasileira de Fisiologia (SBFis), Brazil
| | - Dirceu Sousa Melo
- Centro Integrado de Pós-Graduação e Pesquisa em Saúde (CIPq-Saúde), Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, Minas Gerais, Brazil; Programa Multicêntrico de Pós-Graduação em Ciências Fisiológicas (PMPGCF), Sociedade Brasileira de Fisiologia (SBFis), Brazil
| | - Jeanne Brenda Martins
- Centro Integrado de Pós-Graduação e Pesquisa em Saúde (CIPq-Saúde), Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, Minas Gerais, Brazil; Programa Multicêntrico de Pós-Graduação em Ciências Fisiológicas (PMPGCF), Sociedade Brasileira de Fisiologia (SBFis), Brazil
| | - Washington Pires
- Departamento de Educação Física, Universidade Federal de Juiz de Fora (UFJF), Campus Governador Valadares, Minas Gerais, Brazil
| | | | - Wagner de Fátima Pereira
- Centro Integrado de Pós-Graduação e Pesquisa em Saúde (CIPq-Saúde), Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, Minas Gerais, Brazil; Faculdade de Ciências Biológicas e da Saúde, Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, Minas Gerais, Brazil
| | - Laura Hora Rios Leite
- Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora (UFJF), Juiz de Fora, Minas Gerais, Brazil
| | - Cândido Celso Coimbra
- Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Minas Gerais, Brazil
| | - Hércules Ribeiro Leite
- Centro Integrado de Pós-Graduação e Pesquisa em Saúde (CIPq-Saúde), Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, Minas Gerais, Brazil; Programa Multicêntrico de Pós-Graduação em Ciências Fisiológicas (PMPGCF), Sociedade Brasileira de Fisiologia (SBFis), Brazil
| | - Ana Cristina Rodrigues Lacerda
- Centro Integrado de Pós-Graduação e Pesquisa em Saúde (CIPq-Saúde), Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, Minas Gerais, Brazil; Programa Multicêntrico de Pós-Graduação em Ciências Fisiológicas (PMPGCF), Sociedade Brasileira de Fisiologia (SBFis), Brazil.
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Abdullahi W, Tripathi D, Ronaldson PT. Blood-brain barrier dysfunction in ischemic stroke: targeting tight junctions and transporters for vascular protection. Am J Physiol Cell Physiol 2018; 315:C343-C356. [PMID: 29949404 DOI: 10.1152/ajpcell.00095.2018] [Citation(s) in RCA: 322] [Impact Index Per Article: 53.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The blood-brain barrier (BBB) is a physical and biochemical barrier that precisely controls cerebral homeostasis. It also plays a central role in the regulation of blood-to-brain flux of endogenous and exogenous xenobiotics and associated metabolites. This is accomplished by molecular characteristics of brain microvessel endothelial cells such as tight junction protein complexes and functional expression of influx and efflux transporters. One of the pathophysiological features of ischemic stroke is disruption of the BBB, which significantly contributes to development of brain injury and subsequent neurological impairment. Biochemical characteristics of BBB damage include decreased expression and altered organization of tight junction constituent proteins as well as modulation of functional expression of endogenous BBB transporters. Therefore, there is a critical need for development of novel therapeutic strategies that can protect against BBB dysfunction (i.e., vascular protection) in the setting of ischemic stroke. Such strategies include targeting tight junctions to ensure that they maintain their correct structure or targeting transporters to control flux of physiological substrates for protection of endothelial homeostasis. In this review, we will describe the pathophysiological mechanisms in cerebral microvascular endothelial cells that lead to BBB dysfunction following onset of stroke. Additionally, we will utilize this state-of-the-art knowledge to provide insights on novel pharmacological strategies that can be developed to confer BBB protection in the setting of ischemic stroke.
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Affiliation(s)
- Wazir Abdullahi
- Department of Pharmacology, College of Medicine, University of Arizona , Tucson, Arizona
| | - Dinesh Tripathi
- Department of Pharmacology, College of Medicine, University of Arizona , Tucson, Arizona
| | - Patrick T Ronaldson
- Department of Pharmacology, College of Medicine, University of Arizona , Tucson, Arizona
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15
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Liu DD, Chu SF, Chen C, Yang PF, Chen NH, He X. Research progress in stroke-induced immunodepression syndrome (SIDS) and stroke-associated pneumonia (SAP). Neurochem Int 2018; 114:42-54. [DOI: 10.1016/j.neuint.2018.01.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 01/02/2018] [Accepted: 01/05/2018] [Indexed: 12/12/2022]
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16
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Effects of hyperoxia on 18F-fluoro-misonidazole brain uptake and tissue oxygen tension following middle cerebral artery occlusion in rodents: Pilot studies. PLoS One 2017; 12:e0187087. [PMID: 29091934 PMCID: PMC5665507 DOI: 10.1371/journal.pone.0187087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 10/15/2017] [Indexed: 12/11/2022] Open
Abstract
PURPOSE Mapping brain hypoxia is a major goal for stroke diagnosis, pathophysiology and treatment monitoring. 18F-fluoro-misonidazole (FMISO) positron emission tomography (PET) is the gold standard hypoxia imaging method. Normobaric hyperoxia (NBO) is a promising therapy in acute stroke. In this pilot study, we tested the straightforward hypothesis that NBO would markedly reduce FMISO uptake in ischemic brain in Wistar and spontaneously hypertensive rats (SHRs), two rat strains with distinct vulnerability to brain ischemia, mimicking clinical heterogeneity. METHODS Thirteen adult male rats were randomized to distal middle cerebral artery occlusion under either 30% O2 or 100% O2. FMISO was administered intravenously and PET data acquired dynamically for 3hrs, after which magnetic resonance imaging (MRI) and tetrazolium chloride (TTC) staining were carried out to map the ischemic lesion. Both FMISO tissue uptake at 2-3hrs and FMISO kinetic rate constants, determined based on previously published kinetic modelling, were obtained for the hypoxic area. In a separate group (n = 9), tissue oxygen partial pressure (PtO2) was measured in the ischemic tissue during both control and NBO conditions. RESULTS As expected, the FMISO PET, MRI and TTC lesion volumes were much larger in SHRs than Wistar rats in both the control and NBO conditions. NBO did not appear to substantially reduce FMISO lesion size, nor affect the FMISO kinetic rate constants in either strain. Likewise, MRI and TTC lesion volumes were unaffected. The parallel study showed the expected increases in ischemic cortex PtO2 under NBO, although these were small in some SHRs with very low baseline PtO2. CONCLUSIONS Despite small samples, the apparent lack of marked effects of NBO on FMISO uptake suggests that in permanent ischemia the cellular mechanisms underlying FMISO trapping in hypoxic cells may be disjointed from PtO2. Better understanding of FMISO trapping processes will be important for future applications of FMISO imaging.
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17
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Jiang X, Andjelkovic AV, Zhu L, Yang T, Bennett MVL, Chen J, Keep RF, Shi Y. Blood-brain barrier dysfunction and recovery after ischemic stroke. Prog Neurobiol 2017; 163-164:144-171. [PMID: 28987927 DOI: 10.1016/j.pneurobio.2017.10.001] [Citation(s) in RCA: 504] [Impact Index Per Article: 72.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 05/30/2017] [Accepted: 10/02/2017] [Indexed: 01/06/2023]
Abstract
The blood-brain barrier (BBB) plays a vital role in regulating the trafficking of fluid, solutes and cells at the blood-brain interface and maintaining the homeostatic microenvironment of the CNS. Under pathological conditions, such as ischemic stroke, the BBB can be disrupted, followed by the extravasation of blood components into the brain and compromise of normal neuronal function. This article reviews recent advances in our knowledge of the mechanisms underlying BBB dysfunction and recovery after ischemic stroke. CNS cells in the neurovascular unit, as well as blood-borne peripheral cells constantly modulate the BBB and influence its breakdown and repair after ischemic stroke. The involvement of stroke risk factors and comorbid conditions further complicate the pathogenesis of neurovascular injury by predisposing the BBB to anatomical and functional changes that can exacerbate BBB dysfunction. Emphasis is also given to the process of long-term structural and functional restoration of the BBB after ischemic injury. With the development of novel research tools, future research on the BBB is likely to reveal promising potential therapeutic targets for protecting the BBB and improving patient outcome after ischemic stroke.
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Affiliation(s)
- Xiaoyan Jiang
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA; State Key Laboratory of Medical Neurobiology, Institute of Brain Sciences and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | | | - Ling Zhu
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Tuo Yang
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Michael V L Bennett
- State Key Laboratory of Medical Neurobiology, Institute of Brain Sciences and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Jun Chen
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA; State Key Laboratory of Medical Neurobiology, Institute of Brain Sciences and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Richard F Keep
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Yejie Shi
- Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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18
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Lochhead JJ, Ronaldson PT, Davis TP. Hypoxic Stress and Inflammatory Pain Disrupt Blood-Brain Barrier Tight Junctions: Implications for Drug Delivery to the Central Nervous System. AAPS JOURNAL 2017; 19:910-920. [PMID: 28353217 DOI: 10.1208/s12248-017-0076-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 03/15/2017] [Indexed: 02/08/2023]
Abstract
A functional blood-brain barrier (BBB) is necessary to maintain central nervous system (CNS) homeostasis. Many diseases affecting the CNS, however, alter the functional integrity of the BBB. It has been shown that various diseases and physiological stressors can impact the BBB's ability to selectively restrict passage of substances from the blood to the brain. Modifications of the BBB's permeability properties can potentially contribute to the pathophysiology of CNS diseases and result in altered brain delivery of therapeutic agents. Hypoxia and/or inflammation are central components of a number of diseases affecting the CNS. A number of studies indicate hypoxia or inflammatory pain increase BBB paracellular permeability, induce changes in the expression and/or localization of tight junction proteins, and affect CNS drug uptake. In this review, we look at what is currently known with regard to BBB disruption following a hypoxic or inflammatory insult in vivo. Potential mechanisms involved in altering tight junction components at the BBB are also discussed. A more detailed understanding of the mediators involved in changing BBB functional integrity in response to hypoxia or inflammatory pain could potentially lead to new treatments for CNS diseases with hypoxic or inflammatory components. Additionally, greater insight into the mechanisms involved in TJ rearrangement at the BBB may lead to novel strategies to pharmacologically increase delivery of drugs to the CNS.
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Affiliation(s)
| | | | - Thomas P Davis
- Department of Pharmacology, University of Arizona, Tucson, Arizona, USA.
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19
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Alerted microglia and the sympathetic nervous system: A novel form of microglia in the development of hypertension. Respir Physiol Neurobiol 2016; 226:51-62. [DOI: 10.1016/j.resp.2015.11.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/24/2015] [Accepted: 11/25/2015] [Indexed: 02/07/2023]
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20
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Inoue K, Leng T, Yang T, Zeng Z, Ueki T, Xiong ZG. Role of serum- and glucocorticoid-inducible kinases in stroke. J Neurochem 2016; 138:354-61. [PMID: 27123541 DOI: 10.1111/jnc.13650] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 04/02/2016] [Accepted: 04/22/2016] [Indexed: 01/03/2023]
Abstract
Increased expression of serum- and glucocorticoid-inducible kinase 1 (SGK1) can be induced by stress and growth factors in mammals, and plays an important role in cancer, diabetes, and hypertension. A recent work suggested that SGK1 activity restores damage in a stroke model. To further investigate the role of SGKs in ischemic brain injury, we examined how SGK inhibitors influence stroke outcome in vivo and neurotoxicity in vitro. Infarct volumes were compared in adult mice with middle cerebral artery occlusion, followed by 24 h reperfusion, in the absence or presence of SGK inhibitors. Neurotoxicity assay, electrophysiological recording, and fluorescence Ca(2+) imaging were carried out using cultured cortical neurons to evaluate the underlying mechanisms. Contrary to our expectation, infarct volume by stroke decreased significantly when SGK inhibitor, gsk650394, or EMD638683, was administrated 30 min before middle cerebral artery occlusion under normal and diabetic conditions. SGK inhibitors reduced neurotoxicity mediated by N-methyl-D-aspartate (NMDA) receptors, a leading factor responsible for cell death in stroke. SGK inhibitors also ameliorated Ca(2+) increase and peak amplitude of NMDA current in cultured neurons. In addition, SGK inhibitor gsk650394 decreased phosphorylation of Nedd4-2 and inhibited voltage-gated sodium currents. These observations suggest that SGK activity exacerbates stroke damage and that SGK inhibitors may be useful candidates for therapeutic intervention. To investigate the role of serum- and glucocorticoid-inducible kinases (SGKs) in ischemic brain injury, we examined how SGK inhibitors influence stroke outcome. Infarct volumes induced by middle cerebral artery occlusion were decreased significantly by SGK inhibitors. The inhibitors also reduced glutamate toxicity, at least partly, by attenuation of NMDA and voltage-gated sodium currents. Thus, SGK inhibition attenuates stroke damage.
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Affiliation(s)
- Koichi Inoue
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, USA.,Department of Integrative Anatomy, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Tiandong Leng
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, USA
| | - Tao Yang
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, USA
| | - Zhao Zeng
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, USA
| | - Takatoshi Ueki
- Department of Integrative Anatomy, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Zhi-Gang Xiong
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, Georgia, USA
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21
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Drummond LR, Kunstetter AC, Vaz FF, Campos HO, de Andrade AGP, Coimbra CC, Natali AJ, Wanner SP, Prímola-Gomes TN. Brain Temperature in Spontaneously Hypertensive Rats during Physical Exercise in Temperate and Warm Environments. PLoS One 2016; 11:e0155919. [PMID: 27214497 PMCID: PMC4877067 DOI: 10.1371/journal.pone.0155919] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 04/20/2016] [Indexed: 12/21/2022] Open
Abstract
This study aimed to evaluate brain temperature (Tbrain) changes in spontaneously hypertensive rats (SHRs) subjected to two different physical exercise protocols in temperate or warm environments. We also investigated whether hypertension affects the kinetics of exercise-induced increases in Tbrain relative to the kinetics of abdominal temperature (Tabd) increases. Male 16-week-old normotensive Wistar rats (NWRs) and SHRs were implanted with an abdominal temperature sensor and a guide cannula in the frontal cortex to enable the insertion of a thermistor to measure Tbrain. Next, the animals were subjected to incremental-speed (initial speed of 10 m/min; speed was increased by 1 m/min every 3 min) or constant-speed (60% of the maximum speed) treadmill running until they were fatigued in a temperate (25°C) or warm (32°C) environment. Tbrain, Tabd and tail skin temperature were measured every min throughout the exercise trials. During incremental and constant exercise at 25°C and 32°C, the SHR group exhibited greater increases in Tbrain and Tabd relative to the NWR group. Irrespective of the environment, the heat loss threshold was attained at higher temperatures (either Tbrain or Tabd) in the SHRs. Moreover, the brain-abdominal temperature differential was lower at 32°C in the SHRs than in the NWRs during treadmill running. Overall, we conclude that SHRs exhibit enhanced brain hyperthermia during exercise and that hypertension influences the kinetics of the Tbrain relative to the Tabd increases, particularly during exercise in a warm environment.
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Affiliation(s)
- Lucas Rios Drummond
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Ana Cançado Kunstetter
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Filipe Ferreira Vaz
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Helton Oliveira Campos
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | | | - Cândido Celso Coimbra
- Laboratório de Endocrinologia e Metabolismo, Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Antônio José Natali
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil
| | - Samuel Penna Wanner
- Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - Thales Nicolau Prímola-Gomes
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil
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Möller K, Pösel C, Kranz A, Schulz I, Scheibe J, Didwischus N, Boltze J, Weise G, Wagner DC. Arterial Hypertension Aggravates Innate Immune Responses after Experimental Stroke. Front Cell Neurosci 2015; 9:461. [PMID: 26640428 PMCID: PMC4661280 DOI: 10.3389/fncel.2015.00461] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 11/12/2015] [Indexed: 01/13/2023] Open
Abstract
Arterial hypertension is not only the leading risk factor for stroke, but also attributes to impaired recovery and poor outcome. The latter could be explained by hypertensive vascular remodeling that aggravates perfusion deficits and blood–brain barrier disruption. However, besides vascular changes, one could hypothesize that activation of the immune system due to pre-existing hypertension may negatively influence post-stroke inflammation and thus stroke outcome. To test this hypothesis, male adult spontaneously hypertensive rats (SHRs) and normotensive Wistar Kyoto rats (WKYs) were subjected to photothrombotic stroke. One and 3 days after stroke, infarct volume and functional deficits were evaluated by magnetic resonance imaging and behavioral tests. Expression levels of adhesion molecules and chemokines along with the post-stroke inflammatory response were analyzed by flow cytometry, quantitative real-time PCR and immunohistochemistry in rat brains 4 days after stroke. Although comparable at day 1, lesion volumes were significantly larger in SHR at day 3. The infarct volume showed a strong correlation with the amount of CD45 highly positive leukocytes present in the ischemic hemispheres. Functional deficits were comparable between SHR and WKY. Brain endothelial expression of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and P-selectin (CD62P) was neither increased by hypertension nor by stroke. However, in SHR, brain infiltrating myeloid leukocytes showed significantly higher surface expression of ICAM-1 which may augment leukocyte transmigration by leukocyte–leukocyte interactions. The expression of chemokines that primarily attract monocytes and granulocytes was significantly increased by stroke and, furthermore, by hypertension. Accordingly, ischemic hemispheres of SHR contain considerably higher numbers of monocytes, macrophages and granulocytes. Exacerbated brain inflammation in SHR may finally be responsible for larger infarct volumes. These findings provide an immunological explanation for the epidemiological observation that existing hypertension negatively affects stroke outcome and mortality.
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Affiliation(s)
- Karoline Möller
- Fraunhofer Institute for Cell Therapy and Immunology Leipzig, Germany ; Institute of Anatomy, Histology and Embryology, University of Leipzig Leipzig, Germany
| | - Claudia Pösel
- Fraunhofer Institute for Cell Therapy and Immunology Leipzig, Germany
| | - Alexander Kranz
- Fraunhofer Institute for Cell Therapy and Immunology Leipzig, Germany
| | - Isabell Schulz
- Fraunhofer Institute for Cell Therapy and Immunology Leipzig, Germany
| | - Johanna Scheibe
- Fraunhofer Institute for Cell Therapy and Immunology Leipzig, Germany
| | - Nadine Didwischus
- Fraunhofer Institute for Cell Therapy and Immunology Leipzig, Germany ; Research Group Human Biology, Institute of Biology, University of Leipzig Leipzig, Germany
| | - Johannes Boltze
- Fraunhofer Institute for Cell Therapy and Immunology Leipzig, Germany ; Fraunhofer Research Institution for Marine Biotechnology and Institute for Medical and Marine Biotechnology, University of Lübeck Lübeck, Germany
| | - Gesa Weise
- Fraunhofer Institute for Cell Therapy and Immunology Leipzig, Germany ; Department of Neurology, University of Leipzig Leipzig, Germany
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Yang CC, Li L, Zheng SS, Lu J, Zhang L, Li YL, Zhang L. Cornel iridoid glycoside reduces infarct size measured by magnetic resonance imaging and improves neurological function after focal cerebral ischemia in rats. Chin J Integr Med 2015. [PMID: 26264574 DOI: 10.1007/s11655-015-2288-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To investigate the effect of cornel iridoid glycoside (CIG), an ingredient extracted from traditional Chinese herb Cornus offificinalis, on neurological function and infarct size in rats as measured by magnetic resonance imaging (MRI) after ischemic stroke. METHODS Sprague-Dawley rats were divided into three group: control (n=11), model (n=20) and CIG (n=16) groups. Rats in the model and CIG groups underwent 90-min middle cerebral artery occlusion (MCAO) followed by reperfusion. Their neurological defect was measured by using a modified neurological severity score (mNSS). T2-weighted MRI (T2-MRI) of the brain was performed in vivo from 2 to 28 days after MCAO. The infarct volume in the brain was also measured using 2,3,5-triphenyltetrazolium chloride (TTC) staining 28 days after stroke. RESULTS CIG, 60 mg/(kg day), administered by oral gavage starting from 6 h after the onset of MCAO improved neurological function at 7, 14, 21, and 28 days post occlusion (P<0.05 orP<0.01) and decreased mortality. The infarct volumes computed from the T2-MR images were reduced in the CIG-treated group compared with the model group at 7, 14 and 28 days after MCAO (P<0.05); and the rate at which the infarct volume decreased from 2 to 28 days was higher in the CIG-treated group than that in the model group (P<0.05). The infarct volumes measured by TTC staining were also decreased 28 days after stroke (P<0.05). CONCLUSION CIG treatment, starting from 6 h after MCAO, reduced infarct size in the brain as measured by MRI and improved neurological function 2-28 days after focal cerebral ischemia in rats, suggesting that CIG could be a clinical application in improving stroke treatment.
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Affiliation(s)
- Cui-Cui Yang
- Department of Pharmacology, Xuanwu Hospital of Capital Medical University, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of Ministry of Education, Beijing, 100053, China
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Cerebral angiography, blood flow and vascular reactivity in progressive hypertension. Neuroimage 2015; 111:329-37. [PMID: 25731987 DOI: 10.1016/j.neuroimage.2015.02.053] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 02/18/2015] [Accepted: 02/22/2015] [Indexed: 11/23/2022] Open
Abstract
Chronic hypertension alters cerebral vascular morphology, cerebral blood flow (CBF), cerebrovascular reactivity, and increses susceptibility to neurological disorders. This study evaluated: i) the lumen diameters of major cerebral and downstream arteries using magnetic resonance angiography, ii) basal CBF, and iii) cerebrovascular reactivity to hypercapnia of multiple brain regions using arterial-spin-labeling technique in spontaneously hypertensive rats (SHR) at different stages. Comparisons were made with age-matched normotensive Wistar Kyoto (WKY) rats. In 10-week SHR, lumen diameter started to reduce, basal CBF, and hypercapnic CBF response were higher from elevated arterial blood pressure, but there was no evidence of stenosis, compared to age-matched WKY. In 20-week SHR, lumen diameter remained reduced, CBF returned toward normal from vasoconstriction, hypercapnic CBF response reversed and became smaller, but without apparent stenosis. In 40-week SHR, lumen diameter remained reduced and basal CBF further decreased, resulting in larger differences compared to WKY. There was significant stenosis in main supplying cerebral vessels. Hypercapnic CBF response further decreased, with some animals showing negative hypercapnic CBF responses in some brain regions, indicative of compromised cerebrovascular reserve. The territory with negative hypercapnia CBF responses corresponded with the severity of stenosis in arteries that supplied those territories. We also found enlargement of downstream vessels and formation of collateral vessels as compensatory responses to stenosis of upstream vessels. The middle cerebral and azygos arteries were amongst the most susceptible to hypertension-induced changes. Multimodal MRI provides clinically relevant data that might be useful to characterize disease pathogenesis, stage disease progression, and monitor treatment effects in hypertension.
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Mohammadi MT, Dehghani GA. Acute hypertension induces brain injury and blood–brain barrier disruption through reduction of claudins mRNA expression in rat. Pathol Res Pract 2014; 210:985-90. [DOI: 10.1016/j.prp.2014.05.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 05/05/2014] [Accepted: 05/15/2014] [Indexed: 12/23/2022]
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Blood-brain barrier Na transporters in ischemic stroke. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 71:113-46. [PMID: 25307215 DOI: 10.1016/bs.apha.2014.06.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Blood-brain barrier (BBB) endothelial cells form a barrier that is highly restrictive to passage of solutes between blood and brain. Many BBB transport mechanisms have been described that mediate transcellular movement of solutes across the barrier either into or out of the brain. One class of BBB transporters that is all too often overlooked is that of the ion transporters. The BBB has a rich array of ion transporters and channels that carry Na, K, Cl, HCO3, Ca, and other ions. Many of these are asymmetrically distributed between the luminal and abluminal membranes, giving BBB endothelial cells the ability to perform vectorial transport of ions across the barrier between blood and brain. In this manner, the BBB performs the important function of regulating the volume and composition of brain interstitial fluid. Through functional coupling of luminal and abluminal transporters and channels, the BBB carries Na, Cl, and other ions from blood into brain, producing up to 30% of brain interstitial fluid in healthy brain. During ischemic stroke cerebral edema forms by processes involving increased activity of BBB luminal Na transporters, resulting in "hypersecretion" of Na, Cl, and water into the brain interstitium. This review discusses the roles of luminal BBB Na transporters in edema formation in stroke, with an emphasis on Na-K-Cl cotransport and Na/H exchange. Evidence that these transporters provide effective therapeutic targets for reduction of edema in stroke is also discussed, as are recent findings regarding signaling pathways responsible for ischemia stimulation of the BBB Na transporters.
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McCaffrey G, Davis TP. Physiology and pathophysiology of the blood-brain barrier: P-glycoprotein and occludin trafficking as therapeutic targets to optimize central nervous system drug delivery. J Investig Med 2014; 60:1131-40. [PMID: 23138008 DOI: 10.2310/jim.0b013e318276de79] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The blood-brain barrier (BBB) is a physical and metabolic barrier that separates the central nervous system from the peripheral circulation. Central nervous system drug delivery across the BBB is challenging, primarily because of the physical restriction of paracellular diffusion between the endothelial cells that comprise the microvessels of the BBB and the activity of efflux transporters that quickly expel back into the capillary lumen a wide variety of xenobiotics. Therapeutic manipulation of protein trafficking is emerging as a novel means of modulating protein function, and in this minireview, the targeting of the trafficking of 2 key BBB proteins, P-glycoprotein and occludin, is presented as a novel, reversible means of optimizing central nervous system drug delivery.
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Affiliation(s)
- Gwen McCaffrey
- Department of Medical Pharmacology, University of Arizona College of Medicine, Tucson, AZ 85745, USA.
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Khanna A, Kahle KT, Walcott BP, Gerzanich V, Simard JM. Disruption of ion homeostasis in the neurogliovascular unit underlies the pathogenesis of ischemic cerebral edema. Transl Stroke Res 2013; 5:3-16. [PMID: 24323726 DOI: 10.1007/s12975-013-0307-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/22/2013] [Accepted: 11/06/2013] [Indexed: 02/06/2023]
Abstract
Cerebral edema is a major cause of morbidity and mortality following ischemic stroke, but its underlying molecular pathophysiology is incompletely understood. Recent data have revealed the importance of ion flux via channels and transporters expressed in the neurogliovascular unit in the development of ischemia-triggered cytotoxic edema, vasogenic edema, and hemorrhagic conversion. Disruption of homeostatic mechanisms governing cell volume regulation and epithelial/endothelial ion transport due to ischemia-associated energy failure results in the thermodynamically driven re-equilibration of solutes and water across the CSF-blood and blood-brain barriers that ultimately increases the brain's extravascular volume. Additionally, hypoxia, inflammation, and other stress-triggered increases in the functional expression of ion channels and transporters normally expressed at low levels in the neurogliovascular unit cause disruptions in ion homeostasis that contribute to ischemic cerebral edema. Here, we review the pathophysiological significance of several molecular mediators of ion transport expressed in the neurogliovascular unit, including targets of existing FDA-approved drugs, which might be potential nodes for therapeutic intervention.
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Garcia J, Dang J, Habib P, Beyer C, Kipp M. Comparison of infarct volume and behavioral deficit in Wistar Kyoto and spontaneously hypertensive rat after transient occlusion of the middle cerebral artery. SPRINGERPLUS 2013; 2:414. [PMID: 24024100 PMCID: PMC3765593 DOI: 10.1186/2193-1801-2-414] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 08/23/2013] [Indexed: 12/15/2022]
Abstract
Rodent models of focal cerebral ischemia are important tools in experimental stroke research. Such models have proven instrumental for the understanding of injury mechanisms in cerebral stroke and helped to identify potential new therapeutic options. A plethora of neuroprotective substances have been shown to be effective in preclinical stroke research but failed to prove effectiveness in subsequent clinical trials. Interestingly, preclinical studies have shown that neuroprotective agents are selectively effective in different rat strains. The underlying mechanisms for this discrepancy are so far unknown, but differences in initial stroke volume with concomitant neuroinflammatory processes in the expanding stroke area might be relevant. In the current project, we compared the stroke volume and behavioral outcome between Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR), subjected to transient middle cerebral artery occlusion (tMCAO) for 1 h, followed by 23 h reperfusion. We further analyzed the expression of well-known pro-inflammatory mediators in the cortical peri-infarct area region using a TTC-based isolation approach. Initial reduction of local cerebral blood flow was comparable between both strains. Mean infarct volume and the extent of tMCAO-provoked functional deficits did not differ between WKY and SHR rats. Furthermore, the induction of pro-inflammatory mediators, among CCL3 and CCL5, in the isolated ischemic peri-infarct area region was equal in both rat strains. We were able to demonstrate that stroke outcome is comparable 23 h after transient MCAO in WKY and SHR rats. Future studies have to show whether this observation confirms in the long-term, and which factors contribute to differences observed with respect to therapeutic responsiveness.
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Affiliation(s)
- Jorge Garcia
- Institute of Neuroanatomy, Faculty of Medicine, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
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De Geyter D, Stoop W, Sarre S, De Keyser J, Kooijman R. Neuroprotective efficacy of subcutaneous insulin-like growth factor-I administration in normotensive and hypertensive rats with an ischemic stroke. Neuroscience 2013; 250:253-62. [PMID: 23872393 DOI: 10.1016/j.neuroscience.2013.07.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 07/01/2013] [Accepted: 07/03/2013] [Indexed: 10/26/2022]
Abstract
The aim of this study was to test the insulin-like growth factor-I (IGF-I) as a neuroprotective agent in a rat model for ischemic stroke and to compare its neuroprotective effects in conscious normotensive and spontaneously hypertensive rats. The effects of subcutaneous IGF-I injection were investigated in both rat strains using the endothelin-1 rat model for ischemic stroke. Motor-sensory functions were measured using the Neurological Deficit Score. Infarct size was assessed by Cresyl Violet staining. Subcutaneous administration of IGF-I resulted in significantly reduced infarct volumes and an increase in motor-sensory functions in normotensive rats. In these rats, IGF-I did not modulate blood flow in the striatum and had no effect on the activation of astrocytes as assessed by GFAP staining. In hypertensive rats, the protective effects of IGF-I were smaller and not always significant. Furthermore, IGF-I significantly reduced microglial activation in the cortex of hypertensive rats, but not in normotensive rats. More detailed studies are required to find out whether the reduction by IGF-I of microglial activation contributes to an impairment IGF-I treatment efficacy. Indeed, we have shown before that microglia in hypertensive rats have different properties compared to those in control rats, as they exhibit a reduced responsiveness to ischemic stroke and lipopolysaccharide.
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Affiliation(s)
- D De Geyter
- Center for Neurosciences, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, Brussels, Belgium; Department of Pharmacology, VUB Brussel, Belgium
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Ström JO, Ingberg E, Theodorsson A, Theodorsson E. Method parameters' impact on mortality and variability in rat stroke experiments: a meta-analysis. BMC Neurosci 2013; 14:41. [PMID: 23548160 PMCID: PMC3637133 DOI: 10.1186/1471-2202-14-41] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 03/22/2013] [Indexed: 12/14/2022] Open
Abstract
Background Even though more than 600 stroke treatments have been shown effective in preclinical studies, clinically proven treatment alternatives for cerebral infarction remain scarce. Amongst the reasons for the discrepancy may be methodological shortcomings, such as high mortality and outcome variability, in the preclinical studies. A common approach in animal stroke experiments is that A) focal cerebral ischemia is inflicted, B) some type of treatment is administered and C) the infarct sizes are assessed. However, within this paradigm, the researcher has to make numerous methodological decisions, including choosing rat strain and type of surgical procedure. Even though a few studies have attempted to address the questions experimentally, a lack of consensus regarding the optimal methodology remains. Methods We therefore meta-analyzed data from 502 control groups described in 346 articles to find out how rat strain, procedure for causing focal cerebral ischemia and the type of filament coating affected mortality and infarct size variability. Results The Wistar strain and intraluminal filament procedure using a silicone coated filament was found optimal in lowering infarct size variability. The direct and endothelin methods rendered lower mortality rate, whereas the embolus method increased it compared to the filament method. Conclusions The current article provides means for researchers to adjust their middle cerebral artery occlusion (MCAo) protocols to minimize infarct size variability and mortality.
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Affiliation(s)
- Jakob O Ström
- Department of Clinical and Experimental Medicine, Clinical Chemistry, Faculty of Health Sciences, Linköping University, County Council of Östergötland, Linköping, Sweden.
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O'Donnell ME, Chen YJ, Lam TI, Taylor KC, Walton JH, Anderson SE. Intravenous HOE-642 reduces brain edema and Na uptake in the rat permanent middle cerebral artery occlusion model of stroke: evidence for participation of the blood-brain barrier Na/H exchanger. J Cereb Blood Flow Metab 2013; 33:225-34. [PMID: 23149557 PMCID: PMC3564192 DOI: 10.1038/jcbfm.2012.160] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cerebral edema forms in the early hours of ischemic stroke by processes involving increased transport of Na and Cl from blood into brain across an intact blood-brain barrier (BBB). Our previous studies provided evidence that the BBB Na-K-Cl cotransporter is stimulated by the ischemic factors hypoxia, aglycemia, and arginine vasopressin (AVP), and that inhibition of the cotransporter by intravenous bumetanide greatly reduces edema and infarct in rats subjected to permanent middle cerebral artery occlusion (pMCAO). More recently, we showed that BBB Na/H exchanger activity is also stimulated by hypoxia, aglycemia, and AVP. The present study was conducted to further investigate the possibility that a BBB Na/H exchanger also participates in edema formation during ischemic stroke. Sprague-Dawley rats were subjected to pMCAO and then brain edema and Na content assessed by magnetic resonance imaging diffusion-weighed imaging and magnetic resonance spectroscopy Na spectroscopy, respectively, for up to 210 minutes. We found that intravenous administration of the specific Na/H exchange inhibitor HOE-642 significantly decreased brain Na uptake and reduced cerebral edema, brain swelling, and infarct volume. These findings support the hypothesis that edema formation and brain Na uptake during the early hours of cerebral ischemia involve BBB Na/H exchanger activity as well as Na-K-Cl cotransporter activity.
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Affiliation(s)
- Martha E O'Donnell
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, California 95616, USA.
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Ronaldson PT, Davis TP. Blood-brain barrier integrity and glial support: mechanisms that can be targeted for novel therapeutic approaches in stroke. Curr Pharm Des 2012; 18:3624-44. [PMID: 22574987 DOI: 10.2174/138161212802002625] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/06/2012] [Indexed: 12/31/2022]
Abstract
The blood-brain barrier (BBB) is a critical regulator of brain homeostasis. Additionally, the BBB is the most significant obstacle to effective CNS drug delivery. It possesses specific charcteristics (i.e., tight junction protein complexes, influx and efflux transporters) that control permeation of circulating solutes including therapeutic agents. In order to form this "barrier," brain microvascular endothelial cells require support of adjacent astrocytes and microglia. This intricate relationship also occurs between endothelial cells and other cell types and structures of the CNS (i.e., pericytes, neurons, extracellular matrix), which implies existence of a "neurovascular unit." Ischemic stroke can disrupt the neurovascular unit at both the structural and functional level, which leads to an increase in leak across the BBB. Recent studies have identified several pathophysiological mechanisms (i.e., oxidative stress, activation of cytokine-mediated intracellular signaling systems) that mediate changes in the neurovascular unit during ischemic stroke. This review summarizes current knowledge in this area and emphasizes pathways (i.e., oxidative stress, cytokine-mediated intracellular signaling, glial-expressed receptors/targets) that can be manipulated pharmacologically for i) preservation of BBB and glial integrity during ischemic stroke and ii) control of drug permeation and/or transport across the BBB. Targeting these pathways present a novel opportunity for optimization of CNS delivery of therapeutics in the setting of ischemic stroke.
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Affiliation(s)
- Patrick T Ronaldson
- Department of Medical Pharmacology, College of Medicine, University of Arizona, 1501 North Campbell Avenue, P.O. Box 245050, Tucson, AZ 85724-5050, USA.
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Selvakumar K, Prabha RL, Saranya K, Bavithra S, Krishnamoorthy G, Arunakaran J. Polychlorinated biphenyls impair blood–brain barrier integrity via disruption of tight junction proteins in cerebrum, cerebellum and hippocampus of female Wistar rats. Hum Exp Toxicol 2012; 32:706-20. [DOI: 10.1177/0960327112464798] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Polychlorinated biphenyls (PCBs) comprise a ubiquitous class of toxic substances associated with carcinogenic and tumor-promoting effects as well as neurotoxic properties. Reactive oxygen species, which is produced from PCBs, alters blood–brain barrier (BBB) integrity, which is paralleled by cytoskeletal rearrangements and redistribution and disappearance of tight junction proteins (TJPs) like claudin-5 and occludin. Quercetin, a potent antioxidant present in onion and other vegetables, appears to protect brain cells against oxidative stress, a tissue-damaging process associated with Alzheimer’s and other neurodegenerative disorders. The aim of this study is to analyze the role of quercetin on oxidative stress markers and transcription of transmembrane and cytoplasmic accessory TJPs on cerebrum, cerebellum and hippocampus of female rats exposed to PCBs. Rats were divided into the following four groups. Group I: received only vehicle (corn oil) intraperitoneally (i.p.); group II: received Aroclor 1254 at a dose of 2 mg/kg body weight (bwt)/day (i.p); group III: received Aroclor 1254 (i.p.) and simultaneously quercetin 50 mg/kg bwt/day through gavage and group IV: received quercetin alone gavage. From the experiment, the levels of hydrogen peroxide, lipid peroxidation and thiobarbituric acid reactive substances were observed to increase significantly in cerebrum, cerebellum and hippocampus as 50%, 25% and 20%, respectively, after exposure to PCB, and the messenger RNA expression of TJP in rats exposed to PCBs is decreased and is retrieved to the normal level simultaneously in quercetin-treated rats. Hence, quercetin can be used as a preventive medicine to PCBs exposure and prevents neurodegenerative disorders.
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Affiliation(s)
- K. Selvakumar
- Department of Endocrinology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai, India
| | - R. Lakshmi Prabha
- Department of Endocrinology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai, India
| | - K. Saranya
- Department of Endocrinology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai, India
| | - S. Bavithra
- Department of Endocrinology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai, India
| | - G. Krishnamoorthy
- Department of Biochemistry, Asan Memorial Dental College and Hospital, Asan Nagar, Chengalpattu, India
| | - J. Arunakaran
- Department of Endocrinology, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai, India
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Park S, Shin J, Hong Y, Kim S, Lee S, Park K, Lkhagvasuren T, Lee SR, Chang KT, Hong Y. Forced exercise enhances functional recovery after focal cerebral ischemia in spontaneously hypertensive rats. Brain Sci 2012; 2:483-503. [PMID: 24961257 PMCID: PMC4061815 DOI: 10.3390/brainsci2040483] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 09/03/2012] [Accepted: 10/03/2012] [Indexed: 11/16/2022] Open
Abstract
Caveolin is the principal protein of caveolae and has been implicated in the pathogenesis of cerebral ischemia. To investigate whether changed expression of caveolins has a pivotal role in focal cerebral ischemia, we induced middle cerebral artery occlusion (MCAo)-reperfusion and examined expression of caveolins, inflammatory activation markers, and mediators of autophagic cell death. We also treated MCAo rats with forced exercise to determine its effects on neurological outcome. Particularly, spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats were used to compare the effects of hypertension on focal cerebral ischemia. All MCAo groups showed neurological deficiencies, motor dysfunction, and disruption of balancing ability; however, these pathological changes were more severe in SHR than WKY rats. Expression of caveolins was decreased in MCAo brain tissue, whereas the levels of iNOS and glial fibrillary acidic protein (GFAP) increased. Additionally, LC3-II and beclin-1 levels were elevated in the MCAo groups. Forced exercise attenuated both molecular and behavioral changes in MCAo animals, but SHR rats showed delayed functional recovery and residual molecular changes when compared to WKY rats. These results suggest that forced exercise may be beneficial for promoting functional recovery following cerebral ischemia through caveolin-dependent mechanisms or interactions between caveolins and these signaling molecules in ischemic brain regions.
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Affiliation(s)
- Sookyoung Park
- Cardiovascular & Metabolic Disease Center, College of Biomedical Science & Engineering, Inje University, Gimhae 621-749, Korea.
| | - Jinhee Shin
- Cardiovascular & Metabolic Disease Center, College of Biomedical Science & Engineering, Inje University, Gimhae 621-749, Korea.
| | - Yunkyung Hong
- Department of Rehabilitation Science in Interdisciplinary PhD Program, Graduate School of Inje University, Gimhae 621-749, Korea.
| | - Sunmi Kim
- Cardiovascular & Metabolic Disease Center, College of Biomedical Science & Engineering, Inje University, Gimhae 621-749, Korea.
| | - Seunghoon Lee
- Department of Rehabilitation Science in Interdisciplinary PhD Program, Graduate School of Inje University, Gimhae 621-749, Korea.
| | - Kanghui Park
- Department of Rehabilitation Science in Interdisciplinary PhD Program, Graduate School of Inje University, Gimhae 621-749, Korea.
| | - Tserentogtokh Lkhagvasuren
- Cardiovascular & Metabolic Disease Center, College of Biomedical Science & Engineering, Inje University, Gimhae 621-749, Korea.
| | - Sang-Rae Lee
- National Primate Research Center (NPRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Ochang 363-883, Korea.
| | - Kyu-Tae Chang
- National Primate Research Center (NPRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Ochang 363-883, Korea.
| | - Yonggeun Hong
- Cardiovascular & Metabolic Disease Center, College of Biomedical Science & Engineering, Inje University, Gimhae 621-749, Korea.
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Gursoy-Ozdemir Y, Yemisci M, Dalkara T. Microvascular protection is essential for successful neuroprotection in stroke. J Neurochem 2012; 123 Suppl 2:2-11. [DOI: 10.1111/j.1471-4159.2012.07938.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Yasemin Gursoy-Ozdemir
- Department of Neurology, Institute of Neurological Sciences and Psychiatry; Hacettepe University; Ankara; Turkey
| | - Muge Yemisci
- Department of Neurology, Institute of Neurological Sciences and Psychiatry; Hacettepe University; Ankara; Turkey
| | - Turgay Dalkara
- Department of Neurology, Institute of Neurological Sciences and Psychiatry; Hacettepe University; Ankara; Turkey
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Spontaneously hypertensive rats display reduced microglial activation in response to ischemic stroke and lipopolysaccharide. J Neuroinflammation 2012; 9:114. [PMID: 22647642 PMCID: PMC3410811 DOI: 10.1186/1742-2094-9-114] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 05/30/2012] [Indexed: 01/03/2023] Open
Abstract
Background For successful translation to clinical stroke studies, the Stroke Therapy Academic Industry Round Table criteria have been proposed. Two important criteria are testing of therapeutic interventions in conscious animals and the presence of a co-morbidity factor. We chose to work with hypertensive rats since hypertension is an important modifiable risk factor for stroke and influences the clinical outcome. We aimed to compare the susceptibility to ischemia in hypertensive rats with those in normotensive controls in a rat model for induction of ischemic stroke in conscious animals. Methods The vasoconstrictor endothelin-1 was stereotactically applied in the vicinity of the middle cerebral artery of control Wistar Kyoto rats (WKYRs) and Spontaneously Hypertensive rats (SHRs) to induce a transient decrease in striatal blood flow, which was measured by the Laser Doppler technique. Infarct size was assessed histologically by Cresyl Violet staining. Sensory-motor functions were measured at several time points using the Neurological Deficit Score. Activation of microglia and astrocytes in the striatum and cortex was investigated by immunohistochemistry using antibodies against CD68/Iba-1 and glial fibrillary acidic protein. Results and conclusions The SHRs showed significantly larger infarct volumes and more pronounced sensory-motor deficits, compared to the WKYRs at 24 h after the insult. However, both differences disappeared between 24 and 72 h. In SHRs, microglia were less susceptible to activation by lipopolysaccharide and there was a reduced microglial activation after induction of ischemic stroke. These quantitative and qualitative differences may be relevant for studying the efficacy of new treatments for stroke in accordance to the Stroke Therapy Academic Industry Round Table criteria.
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Li JJ, Xing SH, Zhang J, Hong H, Li YL, Dang C, Zhang YS, Li C, Fan YH, Yu J, Pei Z, Zeng JS. Decrease of tight junction integrity in the ipsilateral thalamus during the acute stage after focal infarction and ablation of the cerebral cortex in rats. Clin Exp Pharmacol Physiol 2011; 38:776-82. [DOI: 10.1111/j.1440-1681.2011.05591.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Takemori K, Inoue T, Ito H. Possible role of nitric oxide generated by leukocytes in the pathogenesis of hypertensive cerebral edema in stroke-prone spontaneously hypertensive rats. Brain Res 2011; 1417:137-45. [DOI: 10.1016/j.brainres.2011.08.042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 08/10/2011] [Accepted: 08/16/2011] [Indexed: 01/13/2023]
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McCaffrey G, Staatz WD, Quigley CA, Nametz N, Seelbach MJ, Campos CR, Brooks TA, Egleton RD, Davis TP. Tight junctions contain oligomeric protein assembly critical for maintaining blood-brain barrier integrity in vivo. J Neurochem 2011; 103:2540-55. [PMID: 17931362 DOI: 10.1111/j.1471-4159.2007.04943.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tight junctions (TJs) are major components of the blood-brain barrier (BBB) that physically obstruct the interendothelial space and restrict paracellular diffusion of blood-borne substances from the peripheral circulation to the CNS. TJs are dynamic structures whose intricate arrangement of oligomeric transmembrane and accessory proteins rapidly alters in response to external stressors to produce changes in BBB permeability. In this study, we investigate the constitutive trafficking of the TJ transmembrane proteins occludin and claudin-5 that are essential for forming the TJ seal between microvascular endothelial cells that inhibits paracellular diffusion. Using a novel, detergent-free OptiPrep density-gradient method to fractionate rat cerebral microvessels, we identify a plasma membrane lipid raft domain that contains oligomeric occludin and claudin-5. Our data suggest that oligomerization of occludin involves disulfide bond formation within transmembrane regions, and that assembly of the TJ oligomeric protein complex is facilitated by an oligomeric caveolin scaffold. This is the first time that distribution of oligomeric TJ transmembrane proteins within plasma membrane lipid rafts at the BBB has been examined in vivo. The findings reported in this study are critical to understand the mechanism of assembly of the TJ multiprotein complex that is essential for maintaining BBB integrity.
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Affiliation(s)
- Gwen McCaffrey
- Department of Medical Pharmacology, University of Arizona College of Medicine, 1501 N. Campbell Ave, Tucson, Arizona, USA.
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Leoni RF, Paiva FF, Henning EC, Nascimento GC, Tannús A, de Araujo DB, Silva AC. Magnetic resonance imaging quantification of regional cerebral blood flow and cerebrovascular reactivity to carbon dioxide in normotensive and hypertensive rats. Neuroimage 2011; 58:75-81. [PMID: 21708273 DOI: 10.1016/j.neuroimage.2011.06.030] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 06/04/2011] [Accepted: 06/09/2011] [Indexed: 11/27/2022] Open
Abstract
Hypertension afflicts 25% of the general population and over 50% of the elderly. In the present work, arterial spin labeling MRI was used to non-invasively quantify regional cerebral blood flow (CBF), cerebrovascular resistance and CO(2) reactivity in spontaneously hypertensive rats (SHR) and in normotensive Wistar Kyoto rats (WKY), at two different ages (3 months and 10 months) and under the effects of two anesthetics, α-chloralose and 2% isoflurane (1.5 MAC). Repeated CBF measurements were highly consistent, differing by less than 10% and 18% within and across animals, respectively. Under α-chloralose, whole brain CBF at normocapnia did not differ between groups (young WKY: 61 ± 3ml/100g/min; adult WKY: 62 ± 4ml/100g/min; young SHR: 70 ± 9ml/100g/min; adult SHR: 69 ± 8ml/100g/min), indicating normal cerebral autoregulation in SHR. At hypercapnia, CBF values increased significantly, and a linear relationship between CBF and PaCO(2) levels was observed. In contrast, 2% isoflurane impaired cerebral autoregulation. Whole brain CBF in SHR was significantly higher than in WKY rats at normocapnia (young SHR: 139 ± 25ml/100g/min; adult SHR: 104 ± 23ml/100g/min; young WKY: 55± 9ml/100g/min; adult WKY: 71 ± 19ml/100g/min). CBF values increased significantly with increasing CO(2); however, there was a clear saturation of CBF at PaCO(2) levels greater than 70mmHg in both young and adult rats, regardless of absolute CBF values, suggesting that isoflurane interferes with the vasodilatory mechanisms of CO(2). This behavior was observed for both cortical and subcortical structures. Under either anesthetic, CO(2) reactivity values in adult SHR were decreased, confirming that hypertension, when combined with age, increases cerebrovascular resistance and reduces cerebrovascular compliance.
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Affiliation(s)
- Renata F Leoni
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892-1065, USA
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Porritt MJ, Chen M, Rewell SSJ, Dean RG, Burrell LM, Howells DW. ACE inhibition reduces infarction in normotensive but not hypertensive rats: correlation with cortical ACE activity. J Cereb Blood Flow Metab 2010; 30:1520-6. [PMID: 20407464 PMCID: PMC2949242 DOI: 10.1038/jcbfm.2010.57] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Angiotensin-converting enzyme (ACE) inhibition can reduce stroke risk by up to 43% in humans and reduce the associated disability, and hence understanding the mechanism of improvement is important. In animals and humans, these effects may be independent of the blood pressure-lowering effects of ACE inhibition. Normotensive (Wistar-Kyoto (WKY)) and hypertensive (spontaneously hypertensive rat (SHR)) animals were treated with the ACE inhibitors ramipril or lisinopril for 7 or 42 days before 2 hours of transient middle cerebral artery occlusion (MCAo). Blood pressure, serum ACE, and blood glucose levels were measured and stroke infarct volume was recorded 24 hours after stroke. Despite greater reductions in blood pressure, infarct size was not improved by ACE inhibition in hypertensive animals. Short-term ACE inhibition produced only a modest reduction in blood pressure, but WKY rats showed marked reductions in infarct volume. Long-term ACE inhibition had additional reductions in blood pressure; however, infarct volumes in WKY rats did not improve further but worsened. WKY rats differed from SHR in having marked cortical ACE activity that was highly sensitive to ACE inhibition. The beneficial effects of ACE inhibition on infarct volume in normotensive rats do not correlate with changes in blood pressure. However, WKY rats have ACE inhibitor-sensitive cortical ACE activity that is lacking in the SHR.
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Affiliation(s)
- Michelle J Porritt
- Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
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Kusch A, Tkachuk S, Tkachuk N, Patecki M, Park JK, Dietz R, Haller H, Dumler I. The tight junction protein ZO-2 mediates proliferation of vascular smooth muscle cells via regulation of Stat1. Cardiovasc Res 2009; 83:115-22. [PMID: 19380416 DOI: 10.1093/cvr/cvp117] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Recent evidence suggests that the zonula occludens protein 2 (ZO-2) might have additional cellular functions, beyond regulation of paracellular permeability of epithelial and endothelial cells. Deregulation of ZO-2 in response to ischaemia, hypertensive stress, and vascular injury implies its involvement in cardiovascular disorders, most likely via regulating the functional behaviour of vascular smooth muscle cells (VSMC). However, a role of ZO-2 in VSMC biology has yet to be established. Our study was designed to understand the specific functions of ZO-2 in human VSMC. METHODS AND RESULTS The expression of ZO-2 and Stat1 upon vascular injury was studied using ex vivo organ culture of coronary arteries combined with immunohistochemistry. ZO-2 silencing in human primary VSMC was achieved by means of lentiviral gene transfer. Cell proliferation was assessed by analysing DNA synthesis and by cell counting. Stat1 expression was examined using immunoblotting, immunocytochemistry, TaqMan, and fluorescence activated cell sorting (FACS) analysis. Functional relevance of Stat1 up-regulation was studied using a Stat1 promoter-luciferase reporter assay and intracellular microinjections of a Stat1 specific antibody. ZO-2 was highly expressed in the media and neointima of dilated but not of control arteries, whereas expression of the transcription factor Stat1 was inversely regulated upon injury. Analysis of VSMC with down-regulated ZO-2 revealed increased expression of Stat1 in these cells, whereas Stat1 phosphorylation was not affected. Stat1 up-regulation in VSMC with ZO-2 silencing resulted in a coordinate activation of Stat1-specific genes and consequently led to inhibition of cell proliferation. This effect was restored by microinjection of a Stat1 neutralising antibody. CONCLUSION Our data suggest that the tight junction protein ZO-2 is involved in regulation of VSMC growth control upon vascular injury that is mediated by the transcription factor Stat1. Our findings point to a novel function of ZO-2 in VSMC and implicate ZO-2 as a novel important molecular target in pathological states of vascular remodelling in cardiovascular diseases.
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Affiliation(s)
- Angelika Kusch
- Medical Faculty of the Charité, Franz Volhard Klinik/Experimental and Clinical Research Center-ECRC, Max Delbrück Center, Berlin, Germany.
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Qu YZ, Li M, Zhao YL, Zhao ZW, Wei XY, Liu JP, Gao L, Gao GD. Astragaloside IV attenuates cerebral ischemia-reperfusion-induced increase in permeability of the blood-brain barrier in rats. Eur J Pharmacol 2009; 606:137-41. [PMID: 19374856 DOI: 10.1016/j.ejphar.2009.01.022] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Revised: 01/08/2009] [Accepted: 01/09/2009] [Indexed: 10/21/2022]
Abstract
Astragalus membranaceus is widely used to treat stroke and chronic debilitating diseases in China, but the mechanism has not been fully demonstrated to data. In the present study, we, using astragaloside IV, a purified extract from astragalus membranaceus, to a focal cerebral ischemia/reperfusion rat model, aimed to investigate the effect of astragaloside IV on the permeability of the blood-brain barrier since disruption of blood-brain barrier induced by ischemia/reperfusion leads to serious brain injuries. We found that astragaloside IV (10, 20 mg/kg) significantly attenuated the permeability of blood-brain barrier in comparison with vehicle group after ischemia/reperfusion assessed via Evans blue leakage (P<0.05). This was further confirmed by examination of blood-brain barrier permeability under the electron microscope, using lanthanum as a tracer of blood vessel permeability. Lanthanum was usually found within the blood vessel in sham group, rather than in perivascular tissues as shown in vehicle group. In drug groups, lanthanum stain was mainly restricted within the cerebral capillary, indicating the potential protective effect of astragaloside IV on the integrity of blood-brain barrier in ischemia/reperfusion rats. Furthermore, we found that expression of occludin and zonae occludens-1 (ZO-1), the tight junction proteins, was decreased in endothelial cells in vehicle group, which, however, could be reversed by astragaloside IV administration. We propose that regulation of tight junctional proteins in the endothelial cells may be one mechanism astragaloside IV-mediated in attribution to blood-brain barrier protection in the ischemia/reperfusion rats.
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Affiliation(s)
- You Zhi Qu
- Department of Neurosurgery, Tangdu Hospital and Institute for Functional Brain Disorders, Baqiao District, Xi'an, PR China
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Shimojima N, Eckman CB, McKinney M, Sevlever D, Yamamoto S, Lin W, Dickson DW, Nguyen JH. Altered expression of zonula occludens-2 precedes increased blood-brain barrier permeability in a murine model of fulminant hepatic failure. J INVEST SURG 2008; 21:101-8. [PMID: 18569429 DOI: 10.1080/08941930802043565] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Brain edema secondary to increased blood-brain barrier (BBB) permeability is a lethal complication in fulminant hepatic failure (FHF). Intact tight junctions (TJ) between brain capillary endothelial cells are critical for normal BBB function. However, the role of TJ in FHF has not been explored. We hypothesized that alterations in the composition of TJ proteins would result in increased BBB permeability in FHF. In this study, FHF was induced in C57BL/6J mice by using azoxymethane. BBB permeability was assessed with sodium fluorescein. Expression of TJ proteins was determined by Western blot, and their cellular distribution was examined using immunofluorescent microscopy. Comatose FHF mice had significant cerebral sodium fluorescein extravasation compared with control and precoma FHF mice, indicating increased BBB permeability. Western blot analysis showed a significant decrease in zonula occludens (ZO)-2 expression starting in the precoma stage. Immunofluorescent microscopy showed a significantly altered distribution pattern of ZO-2 in isolated microvessels from precoma FHF mice. These changes were more prominent in comatose FHF animals. Significant alterations in ZO-2 expression and distribution in the tight junctions preceded the increased BBB permeability in FHF mice. These results suggest that ZO-2 may play an important role in the pathogenesis of brain edema in FHF.
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Affiliation(s)
- Naoki Shimojima
- Department of Transplantation, Division of Transplant Surgery, Mayo Clinic College of Medicine, Jacksonville, FL 32216, USA
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Eum SY, András IE, Couraud PO, Hennig B, Toborek M. Pcbs and tight junction expression. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2008; 25:234-40. [PMID: 18438464 PMCID: PMC2346445 DOI: 10.1016/j.etap.2007.10.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Polychlorinated biphenyl (PCB) congeners exhibit a broad range of adverse biological effects including neurotoxicity. The mechanisms by which PCBs cause neurotoxic effects are still not completely understood. The blood-brain barrier (BBB) is a physical and metabolic barrier separating brain microenvironment from the peripheral circulation and is mainly composed of endothelial cells connected by tight junctions. We examined the effects of several highly-chlorinated PCB congeners on expression of tight junction proteins in human brain endothelial cells. Treatment for 24 h with selective PCB congeners disrupted expression of the cytosolic scaffold proteins of tight junctions, such as zonula occludens (ZO)-1, ZO-2, and AF6. In contrast, PCB exposure did not alter expression of integral membrane proteins, junctional adhesion molecule-A (JAM-A), and claudin-1. Based on these data, we suggest that PCB-mediated selective alterations of tight junction protein expression may contribute to their neurotoxic effects in the central nervous system.
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Affiliation(s)
- Sung Yong Eum
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky, Lexington, KY 40536
| | - Ibolya E. András
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky, Lexington, KY 40536
| | | | - Bernhard Hennig
- College of Agriculture, University of Kentucky, Lexington, KY 40536
| | - Michal Toborek
- Molecular Neuroscience and Vascular Biology Laboratory, Department of Neurosurgery, University of Kentucky, Lexington, KY 40536
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Abstract
The specialized cerebral microvascular endothelium interacts with the cellular milieu of the brain and extracellular matrix to form a neurovascular unit, one aspect of which is a regulated interface between the blood and central nervous system (CNS). The concept of this blood-brain barrier (BBB) as a dynamically regulated system rather than a static barrier has wide-ranging implications for pathophysiology of the CNS. While in vitro models of the BBB are useful for screening drugs targeted to the CNS and indispensable for studies of cerebral endothelial cell biology, the complex interactions of the neurovascular unit make animal-based models and methods essential tools for understanding the pathophysiology of the BBB. BBB dysfunction is a complication of neurodegenerative disease and brain injury. Studies on animal models have shown that diseases of the periphery, such as diabetes and inflammatory pain, have deleterious effects on the BBB which may contribute to neurological complications associated with these conditions. Furthermore, genetic and/or epigenetic abnormalities in constituents of the BBB may be significant contributing factors in disease etiology. Research that approaches the BBB as a dynamic system integrated with both the CNS and the periphery is therefore critical to understanding and treating diseases of the CNS. Herein, we review various methodological approaches used to study BBB function in the context of disease. These include measurement of transport between blood and brain, imaging-based technologies, and genomic/proteomic approaches.
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