1
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Li Y, Faiz A, Moshage H, Schilling L, Kamps JAAM. Responses of retinal and brain microvasculature to streptozotocin induced diabetes revealed by global expression profiling. Diab Vasc Dis Res 2023; 20:14791641221147533. [PMID: 36606460 PMCID: PMC9982389 DOI: 10.1177/14791641221147533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
This study aims to determine the effects of diabetes in the retinal and brain microvasculature through gene expression profiling. Twelve male Wistar rats were randomly divided into two groups: streptozotocin-induced diabetic rats and time-matched nondiabetic rats. The retinal microvessels (RMVs) and brain microvessels (BMVs) were mechanically isolated from individual rats. Differentially expressed genes (DEGs) in diabetic and nondiabetic microvessels were identified by cDNA microarrays analysis. In RMVs, we identified 43 DEGs, of which 20 were upregulated while 23 were downregulated by diabetes. In BMVs, 35 genes DEGs were identified, of which 22 were upregulated and 13 were downregulated by diabetes. Altered expression of the Nars, Gars, Mars, Iars, Yars, Bcl2, Nqo1, NR4A3, Gpd1, Stc1, Tsc22d3, Tnfrsf21 mRNA as observed in the microarray analyses, was confirmed by quantitative RT-PCR. The aminoacyl-tRNA synthetases (aaRSs) pathway in RMVs was significantly overrepresented as compared to BMVs. Our study demonstrates for the first time that in the brain microvasculature multiple compensatory mechanisms exists, serving to protect brain tissue from diabetic insults, whereas these mechanisms are not activated in the retinal microvasculature. This provides new insights as to why brain microvasculature is less susceptible to diabetes.
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Affiliation(s)
- Youhai Li
- Division of Neurosurgical Research, Heidelberg University, Mannheim, Germany; European Center of Angioscience, Medical
Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Department of Pathology and Medical
Biology, University Medical Center
Groningen, Groningen, The Netherlands
| | - Alen Faiz
- Department of Pathology and Medical
Biology, University Medical Center
Groningen, Groningen, The Netherlands
| | - Han Moshage
- Department of Gastroenterology and
Hepatology, University Medical Center
Groningen, Groningen, The Netherlands
| | - Lothar Schilling
- Division of Neurosurgical Research, Heidelberg University, Mannheim, Germany; European Center of Angioscience, Medical
Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Jan AAM Kamps
- Department of Pathology and Medical
Biology, University Medical Center
Groningen, Groningen, The Netherlands
- Jan AAM Kamps, Department of Pathology and
Medical Biology, University of Groningen, University Medical Center Groningen,
Hanzeplein 1 (EA11), 9713GZ Groningen, The Netherlands.
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2
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Li X, Cai Y, Zhang Z, Zhou J. Glial and Vascular Cell Regulation of the Blood-Brain Barrier in Diabetes. Diabetes Metab J 2022; 46:222-238. [PMID: 35299293 PMCID: PMC8987684 DOI: 10.4093/dmj.2021.0146] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 01/20/2022] [Indexed: 12/18/2022] Open
Abstract
As a structural barrier, the blood-brain barrier (BBB) is located at the interface between the brain parenchyma and blood, and modulates communication between the brain and blood microenvironment to maintain homeostasis. The BBB is composed of endothelial cells, basement membrane, pericytes, and astrocytic end feet. BBB impairment is a distinguishing and pathogenic factor in diabetic encephalopathy. Diabetes causes leakage of the BBB through downregulation of tight junction proteins, resulting in impaired functioning of endothelial cells, pericytes, astrocytes, microglia, nerve/glial antigen 2-glia, and oligodendrocytes. However, the temporal regulation, mechanisms of molecular and signaling pathways, and consequences of BBB impairment in diabetes are not well understood. Consequently, the efficacy of therapies diabetes targeting BBB leakage still lags behind the requirements. This review summarizes the recent research on the effects of diabetes on BBB composition and the potential roles of glial and vascular cells as therapeutic targets for BBB disruption in diabetic encephalopathy.
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Affiliation(s)
- Xiaolong Li
- National Drug Clinical Trial Institution, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Yan Cai
- National Drug Clinical Trial Institution, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Zuo Zhang
- National Drug Clinical Trial Institution, Second Affiliated Hospital, Army Medical University, Chongqing, China
| | - Jiyin Zhou
- National Drug Clinical Trial Institution, Second Affiliated Hospital, Army Medical University, Chongqing, China
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3
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Liu Y, Chen D, Smith A, Ye Q, Gao Y, Zhang W. Three-dimensional remodeling of functional cerebrovascular architecture and gliovascular unit in leptin receptor-deficient mice. J Cereb Blood Flow Metab 2021; 41:1547-1562. [PMID: 33818188 PMCID: PMC8221780 DOI: 10.1177/0271678x211006596] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 12/17/2022]
Abstract
The cerebrovascular sequelae of diabetes render victims more susceptible to ischemic stroke, vascular cognitive impairment, and Alzheimer's disease. However, limited knowledge exists on the progressive changes in cerebrovascular structure and functional remodeling in type 2 diabetes. To ascertain the impact of diabetes on whole-brain cerebrovascular perfusion, leptin-receptor-deficient mice were transcardially injected with tomato-lectin before sacrifice. The whole brain was clarified by the Fast free-of-acrylamide clearing tissue technique. Functional vascular anatomy of the cerebrum was visualized by light-sheet microscopy, followed by analysis in Imaris software. We observed enhanced neovascularization in adult db/db mice, characterized by increased branch level and loop structures. Microvascular hypoperfusion was initially detected in juvenile db/db mice, suggesting early onset of insufficient microcirculation. Furthermore, gliovascular unit remodeling was verified by loss of pericytes and overactivation of microglia and astrocytes in adult diabetic mice. However, the integrity of the blood-brain barrier (BBB) was fundamentally preserved, as shown by a lack of extravasation of IgG into the brain parenchyma. In summary, we, for the first time, reveal that functional cerebrovascular remodeling occurs as early as four weeks in db/db mice and the deficit in gliovascular coupling may play a role in cerebral hypoperfusion before BBB breakdown in 16-week-old db/db mice.
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Affiliation(s)
- Yaan Liu
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Di Chen
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Amanda Smith
- Department of Neurology, Pittsburgh Institute of Brain Disorders & Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Qing Ye
- Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA, USA
| | - Yanqin Gao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Wenting Zhang
- Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA, USA
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4
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Sharma S, Brown CE. Microvascular basis of cognitive impairment in type 1 diabetes. Pharmacol Ther 2021; 229:107929. [PMID: 34171341 DOI: 10.1016/j.pharmthera.2021.107929] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/23/2021] [Accepted: 05/19/2021] [Indexed: 02/07/2023]
Abstract
The complex computations of the brain require a constant supply of blood flow to meet its immense metabolic needs. Perturbations in blood supply, even in the smallest vascular networks, can have a profound effect on neuronal function and cognition. Type 1 diabetes is a prevalent and insidious metabolic disorder that progressively and heterogeneously disrupts vascular signalling and function in the brain. As a result, it is associated with an array of adverse vascular changes such as impaired regulation of vascular tone, pathological neovascularization and vasoregression, capillary plugging and blood brain barrier disruption. In this review, we highlight the link between microvascular dysfunction and cognitive impairment that is commonly associated with type 1 diabetes, with the aim of synthesizing current knowledge in this field.
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Affiliation(s)
- Sorabh Sharma
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Craig E Brown
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada; Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada.
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5
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Dysfunction of the neurovascular unit in diabetes-related neurodegeneration. Biomed Pharmacother 2020; 131:110656. [PMID: 32841897 DOI: 10.1016/j.biopha.2020.110656] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/10/2020] [Accepted: 08/17/2020] [Indexed: 12/13/2022] Open
Abstract
In current aging societies, diabetes mellitus and neurodegenerative diseases represented by Alzheimer's disease are highly prevalent among adults, especially the elderly all over the world. It is worth noting that a substantial body of evidence suggests diabetes contributes to accelerated neurodegenerative processes and the decline of cognition. Over the last few years, some studies have indicated neurovascular uncoupling and disrupted functional connectivity in the early stages of many neurodegenerative diseases, and the concept of the neurovascular unit (NVU) has been highlighted to understand the initiation and progression of neurodegenerative diseases recently. Considering that some components of the NVU are also demonstrated to have abnormal morphology and function under the condition of diabetes, we propose the hypothesis that diabetes may promote the onset and development of neurodegenerative diseases by impairing the integrity of the NVU, named Diabetes-NVU-Neurodegeneration Hypothesis. The existing body of literature supporting the hypothesis and elucidating the underlying mechanisms will be summarized in this review.
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6
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Banks WA. The Blood-Brain Barrier Interface in Diabetes Mellitus: Dysfunctions, Mechanisms and Approaches to Treatment. Curr Pharm Des 2020; 26:1438-1447. [DOI: 10.2174/1381612826666200325110014] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 02/27/2020] [Indexed: 12/24/2022]
Abstract
Diabetes mellitus (DM) is one of the most common diseases in the world. Among its effects are an increase in the risk of cognitive impairment, including Alzheimer’s disease, and blood-brain barrier (BBB) dysfunction. DM is characterized by high blood glucose levels that are caused by either lack of insulin (Type I) or resistance to the actions of insulin (Type II). The phenotypes of these two types are dramatically different, with Type I animals being thin, with low levels of leptin as well as insulin, whereas Type II animals are often obese with high levels of both leptin and insulin. The best characterized change in BBB dysfunction is that of disruption. The brain regions that are disrupted, however, vary between Type I vs Type II DM, suggesting that factors other than hyperglycemia, perhaps hormonal factors such as leptin and insulin, play a regionally diverse role in BBB vulnerability or protection. Some BBB transporters are also altered in DM, including P-glycoprotein, lowdensity lipoprotein receptor-related protein 1, and the insulin transporter as other functions of the BBB, such as brain endothelial cell (BEC) expression of matrix metalloproteinases (MMPs) and immune cell trafficking. Pericyte loss secondary to the increased oxidative stress of processing excess glucose through the Krebs cycle is one mechanism that has shown to result in BBB disruption. Vascular endothelial growth factor (VEGF) induced by advanced glycation endproducts can increase the production of matrix metalloproteinases, which in turn affects tight junction proteins, providing another mechanism for BBB disruption as well as effects on P-glycoprotein. Through the enhanced expression of the redox-related mitochondrial transporter ABCB10, redox-sensitive transcription factor NF-E2 related factor-2 (Nrf2) inhibits BEC-monocyte adhesion. Several potential therapies, in addition to those of restoring euglycemia, can prevent some aspects of BBB dysfunction. Carbonic anhydrase inhibition decreases glucose metabolism and so reduces oxidative stress, preserving pericytes and blocking or reversing BBB disruption. Statins or N-acetylcysteine can reverse the BBB opening in some models of DM, fibroblast growth factor-21 improves BBB permeability through an Nrf2-dependent pathway, and nifedipine or VEGF improves memory in DM models. In summary, DM alters various aspects of BBB function through a number of mechanisms. A variety of treatments based on those mechanisms, as well as restoration of euglycemia, may be able to restore BBB functions., including reversal of BBB disruption.
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Affiliation(s)
- William A. Banks
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, United States
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7
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Liu L, Liu X. Contributions of Drug Transporters to Blood-Brain Barriers. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1141:407-466. [PMID: 31571171 DOI: 10.1007/978-981-13-7647-4_9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Blood-brain interfaces comprise the cerebral microvessel endothelium forming the blood-brain barrier (BBB) and the epithelium of the choroid plexuses forming the blood-cerebrospinal fluid barrier (BCSFB). Their main functions are to impede free diffusion between brain fluids and blood; to provide transport processes for essential nutrients, ions, and metabolic waste products; and to regulate the homeostasis of central nervous system (CNS), all of which are attributed to absent fenestrations, high expression of tight junction proteins at cell-cell contacts, and expression of multiple transporters, receptors, and enzymes. Existence of BBB is an important reason that systemic drug administration is not suitable for the treatment of CNS diseases. Some diseases, such epilepsy, Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and diabetes, alter BBB function via affecting tight junction proteins or altering expression and function of these transporters. This chapter will illustrate function of BBB, expression of transporters, as well as their alterations under disease status.
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Affiliation(s)
- Li Liu
- China Pharmaceutical University, Nanjing, China
| | - Xiaodong Liu
- China Pharmaceutical University, Nanjing, China.
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8
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Xu Y, Zhou H, Zhu Q. The Impact of Microbiota-Gut-Brain Axis on Diabetic Cognition Impairment. Front Aging Neurosci 2017; 9:106. [PMID: 28496408 PMCID: PMC5406474 DOI: 10.3389/fnagi.2017.00106] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 03/31/2017] [Indexed: 12/11/2022] Open
Abstract
Progressive cognitive dysfunction is a central characteristic of diabetic encephalopathy (DE). With an aging population, the incidence of DE is rising and it has become a major threat that seriously affects public health. Studies within this decade have indicated the important role of risk factors such as oxidative stress and inflammation on the development of cognitive impairment. With the recognition of the two-way communication between gut and brain, recent investigation suggests that “microbiota-gut-brain axis” also plays a pivotal role in modulating both cognition function and endocrine stability. This review aims to systemically elucidate the underlying impact of diabetes on cognitive impairment.
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Affiliation(s)
- Youhua Xu
- Faculty of Chinese Medicine, Macau University of Science and TechnologyTaipa, Macau.,State Key Laboratory of Quality Research in Chinese Medicine (Macau University of Science and Technology)Taipa, Macau
| | - Hua Zhou
- Faculty of Chinese Medicine, Macau University of Science and TechnologyTaipa, Macau.,State Key Laboratory of Quality Research in Chinese Medicine (Macau University of Science and Technology)Taipa, Macau.,Laboratory for Bioassay and Molecular Pharmacology of Chinese Medicines, Macau Institute for Applied Research in Medicine and HealthTaipa, Macau
| | - Quan Zhu
- Faculty of Chinese Medicine, Macau University of Science and TechnologyTaipa, Macau.,State Key Laboratory of Quality Research in Chinese Medicine (Macau University of Science and Technology)Taipa, Macau.,Laboratory for Bioassay and Molecular Pharmacology of Chinese Medicines, Macau Institute for Applied Research in Medicine and HealthTaipa, Macau.,Guangdong Consun Pharmaceutical Group, Institute of Consun Co. for Chinese Medicine in Kidney DiseasesGuangzhou, China
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9
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Ito S, Yanai M, Yamaguchi S, Couraud PO, Ohtsuki S. Regulation of Tight-Junction Integrity by Insulin in an In Vitro Model of Human Blood-Brain Barrier. J Pharm Sci 2017; 106:2599-2605. [PMID: 28456720 DOI: 10.1016/j.xphs.2017.04.036] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/14/2017] [Accepted: 04/17/2017] [Indexed: 12/30/2022]
Abstract
Although insulin receptor is expressed at the human blood-brain barrier (BBB), the physiological and pathologic roles of insulin signaling in biologic responses at the BBB remain unclear. Here, we investigate insulin signaling at the human BBB using human cerebral microvascular endothelial cell line (hCMEC/D3) as a well-established in vitro model. Western blot analysis showed that insulin induced phosphorylation of extracellular signal-regulated kinase and insulin receptor substrate-1 in hCMEC/D3 cells. Short-term insulin stimulation increased cell proliferation via the canonical phosphoinositide-3 kinase/protein kinase B and mitogen-activated protein kinase signaling pathways, suggesting that insulin signaling is involved in the regulation of biologic responses in the human BBB. We also found that insulin rapidly increased tight-junction integrity of hCMEC/D3 cells via the phosphoinositide-3 kinase/protein kinase B/glycogen synthase kinase-3 β signaling pathway. Inhibition of insulin/insulin-like growth factor-1 receptor kinase by AG1024 blocked the increase of tight-junction integrity. In addition, high-insulin/high-glucose treatment (as a model of hyperglycemia and hyperinsulinemia) synergistically reduced the tight-junction integrity in hCMEC/D3 cells, although either condition alone had little or no effect. Our findings suggest that, in addition to the established role of interactions of astrocytes and pericytes with brain capillary endothelial cells, insulin signaling from the blood side of the BBB contributes to maintenance of homeostasis by regulating cell proliferation and tight-junction integrity.
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Affiliation(s)
- Shingo Ito
- Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan; Department of Pharmaceutical Microbiology, School of Pharmacy, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan; Department of Pharmaceutical Microbiology, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan; AMED-CREST, Japan Agency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda, Tokyo 100-0004, Japan
| | - Mari Yanai
- Department of Pharmaceutical Microbiology, School of Pharmacy, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Shunsuke Yamaguchi
- Department of Pharmaceutical Microbiology, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Pierre-Olivier Couraud
- Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Sumio Ohtsuki
- Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan; Department of Pharmaceutical Microbiology, School of Pharmacy, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan; Department of Pharmaceutical Microbiology, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan; AMED-CREST, Japan Agency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda, Tokyo 100-0004, Japan.
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10
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Zanotto C, Simão F, Gasparin MS, Biasibetti R, Tortorelli LS, Nardin P, Gonçalves CA. Exendin-4 Reverses Biochemical and Functional Alterations in the Blood-Brain and Blood-CSF Barriers in Diabetic Rats. Mol Neurobiol 2016; 54:2154-2166. [PMID: 26927659 DOI: 10.1007/s12035-016-9798-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 02/16/2016] [Indexed: 01/08/2023]
Abstract
Diabetes mellitus (DM) is a metabolic disorder associated with micro- and macrovascular alterations that contribute to the cognitive impairment observed in diabetic patients. Signs of breakdown of the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) have been found in patients and animal models of DM. Breakdown of the BBB and BCSFB can lead to disruptions in cerebral homeostasis and eventually neural dysfunction and degeneration. However, our understanding of the biochemistry underlying barrier protein modifications is incomplete. Herein, we evaluated changes in the levels of specific proteins in the BBB (occludin, claudin-5, ZO-1, and aquaporin-4) and BCSFB (claudin-2 and aquaporin-1) in the hippocampus of diabetic rats, and we also investigated the functional alterations in these barriers. In addition, we evaluated the ability of exendin-4 (EX-4), a glucagon-like peptide-1 agonist that can cross the BBB to reverse the functional and biochemical modifications observed in these animals. We observed a decrease in BBB proteins (except ZO-1) in diabetic rats, whereas the EX-4 treatment recovered the occludin and aquaporin-4 levels. Similarly, we observed a decrease in BCSFB proteins in diabetic rats, whereas EX-4 reversed such changes. EX-4 also reversed alterations in the permeability of the BBB and BCSFB in diabetic rats. Additionally, altered cognitive parameters in diabetic rats were improved by EX-4. These data further our understanding of the alterations in the central nervous system caused by DM, particularly changes in the proteins and permeability of the brain barriers, as well as cognitive dysfunction. Furthermore, these data suggest a role for EX-4 in therapeutic strategies for cognitive dysfunction in DM.
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Affiliation(s)
- Caroline Zanotto
- Biochemistry Department, Basic Sciences Institute of Health, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Fabrício Simão
- Research Division, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Manuela Sangalli Gasparin
- Biochemistry Department, Basic Sciences Institute of Health, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Regina Biasibetti
- Biochemistry Department, Basic Sciences Institute of Health, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Lucas Silva Tortorelli
- Biochemistry Department, Basic Sciences Institute of Health, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Patrícia Nardin
- Biochemistry Department, Basic Sciences Institute of Health, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
| | - Carlos-Alberto Gonçalves
- Biochemistry Department, Basic Sciences Institute of Health, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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11
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Lazard D, Vardi P, Bloch K. Anti-diabetic and neuroprotective effects of pancreatic islet transplantation into the central nervous system. Diabetes Metab Res Rev 2016; 32:11-20. [PMID: 25708430 DOI: 10.1002/dmrr.2644] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 02/19/2015] [Indexed: 12/19/2022]
Abstract
During the last decades, the central nervous system (CNS) was intensively tested as a site for islet transplantation in different animal models of diabetes. Immunoprivilege properties of intracranial and intrathecal sites were found to delay and reduce rejection of transplanted allo-islets and xeno-islets, especially in the form of dispersed single cells. Insulin released from islets grafted in CNS was shown to cross the blood-brain barrier and to act as a regulator of peripheral glucose metabolism. In diabetic animals, sufficient nutrition and oxygen supply to islets grafted in the CNS provide adequate insulin response to increase glucose level resulting in rapid normoglycemia. In addition to insulin, pancreatic islets produce and secrete several other hormones, as well as neurotrophic and angiogenic factors with potential neuroprotective properties. Recent experimental studies and clinical trials provide a strong support for delivery of islet-derived macromolecules to CNS as a promising strategy to treat various brain disorders. This review article focuses mainly on analysis of current status of intracranial and intrathecal islet transplantations for treatment of experimental diabetes and discusses the possible neuroprotective properties of grafted islets into CNS as a novel therapeutic approach to brain disorders with cognitive dysfunctions characterized by impaired brain insulin signalling. Copyright © 2015 John Wiley & Sons, Ltd.
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MESH Headings
- Animals
- Blood-Brain Barrier
- Brain
- Central Nervous System
- Diabetes Mellitus, Type 1/blood
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/surgery
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/surgery
- Diabetic Neuropathies/prevention & control
- Disease Models, Animal
- Humans
- Hyperglycemia/prevention & control
- Hypoglycemia/prevention & control
- Insulin/metabolism
- Insulin Resistance
- Insulin Secretion
- Islets of Langerhans Transplantation/adverse effects
- Spinal Cord
- Subarachnoid Space
- Transplantation, Heterologous/adverse effects
- Transplantation, Heterotopic/adverse effects
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Affiliation(s)
- Daniel Lazard
- Laboratory of Diabetes and Obesity Research, Felsenstein Medical Research Center, Sackler School of Medicine, Tel Aviv University, Petah Tikva, Israel
| | - Pnina Vardi
- Laboratory of Diabetes and Obesity Research, Felsenstein Medical Research Center, Sackler School of Medicine, Tel Aviv University, Petah Tikva, Israel
| | - Konstantin Bloch
- Laboratory of Diabetes and Obesity Research, Felsenstein Medical Research Center, Sackler School of Medicine, Tel Aviv University, Petah Tikva, Israel
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12
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Kalani A, Kamat PK, Tyagi N. Diabetic Stroke Severity: Epigenetic Remodeling and Neuronal, Glial, and Vascular Dysfunction. Diabetes 2015; 64:4260-71. [PMID: 26470785 PMCID: PMC4876759 DOI: 10.2337/db15-0422] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 08/28/2015] [Indexed: 01/02/2023]
Abstract
We determined the mechanism of severity during type 1 diabetic (T1D) stroke (ischemia-reperfusion [IR] injury) that affects potential markers associated with epigenetics, neuronal, glial, and vascular components of the brain with regard to nondiabetic stroke. The study used male genetic T1D Ins2(+/-) Akita and wild-type (C57BL/6J) mice. The experimental mice groups were 1) sham, 2) IR, 3) sham(Akita), and 4) IR(Akita). Mice were subjected to middle cerebral artery occlusion for 40 min, followed by reperfusion for 24 h. Brain tissues were analyzed for inflammation, neuro-glio-vascular impairments, matrix metalloproteinase (MMP)-9 expression, and epigenetic alterations (DNA methyltransferase-3a [DNMT-3a]; DNA methyltransferase-1 [DNMT-1]; 5-methylcytosine [5-mC]; and 5-hydroxymethylcytosine [5-hmC]). Intracarotid fluorescein isothiocyanate-BSA infusion was used to determine pial-venular permeability. IR(Akita) mice showed more infarct volume, edema, inflammation, and vascular MMP-9 expression compared with IR and sham groups. Sham(Akita) mice showed the highest DNMT-1 and DNMT-3a levels compared with the other groups. Reduced tight and adherent junction expressions and severe venular leakage exemplified intense cerebrovascular impairment in IR(Akita) mice compared with the other groups. Interestingly, we found differential regulations (downregulated expression) of epigenetic (5-mC, DNMTs), vascular (endothelial nitric oxide synthase), glial (connexin-43, glial fibrillary acidic protein, CD11b), and neuronal (neuron-specific enolase, neuronal nitric oxide synthase) markers in IR(Akita) compared with the IR group. These findings suggest that IR injury in T1D is more severe because it intensifies differential epigenetic markers and neuro-glio-vascular changes compared with nondiabetic mice.
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Affiliation(s)
- Anuradha Kalani
- Department of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, KY
| | - Pradip Kumar Kamat
- Department of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, KY
| | - Neetu Tyagi
- Department of Physiology and Biophysics, School of Medicine, University of Louisville, Louisville, KY
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13
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Sickmann HM, Waagepetersen HS. Effects of diabetes on brain metabolism--is brain glycogen a significant player? Metab Brain Dis 2015; 30:335-43. [PMID: 24771109 DOI: 10.1007/s11011-014-9546-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 04/10/2014] [Indexed: 10/25/2022]
Abstract
Brain glycogen, being an intracellular glucose reservoir, contributes to maintain energy and neurotransmitter homeostasis under physiological as well as pathological conditions. Under conditions with a disturbance in systemic glucose metabolism such as in diabetes, the supply of glucose to the brain may be affected and have important impacts on brain metabolism and neurotransmission. This also implies that brain glycogen may serve an essential role in the diabetic state to sustain appropriate brain function. There are two main types of diabetes; type 1 and type 2 diabetes and both types may be associated with brain impairments e.g. cognitive decline and dementia. It is however, not clear how these impairments on brain function are linked to alterations in brain energy and neurotransmitter metabolism. In this review, we will illuminate how rodent diabetes models have contributed to a better understanding of how brain energy and neurotransmitter metabolism is affected in diabetes. There will be a particular focus on the role of brain glycogen to support glycolytic and TCA cycle activity as well as glutamate-glutamine cycle in type 1 and type 2 diabetes.
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Affiliation(s)
- Helle M Sickmann
- Dept. of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark,
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Liu L, Liu XD. Alterations in function and expression of ABC transporters at blood-brain barrier under diabetes and the clinical significances. Front Pharmacol 2014; 5:273. [PMID: 25540622 PMCID: PMC4261906 DOI: 10.3389/fphar.2014.00273] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Accepted: 11/24/2014] [Indexed: 11/13/2022] Open
Abstract
Diabetes is a systematic metabolic disease, which often develops a number of well-recognized vascular complications including brain complications which may partly result from the dysfunction of blood-brain barrier (BBB). BBB is generally considered as a mechanism for protecting the brain from unwanted actions resulting from substances in the blood and maintaining brain homeostasis via monitoring the entry or efflux of compounds. ATP-binding cassette (ABC) family of transporters including P-glycoprotein (P-GP) and breast cancer-related protein (BCRP), widely expressed in the luminal membrane of the microvessel endothelium and in the apical membrane of the choroids plexus epithelium, play important roles in the function of BBB. However, these transporters are easily altered by some diseases. The present article was focused on the alteration in expression and function of both P-GP and BCRP at BBB by diabetes and the clinical significances.
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Affiliation(s)
- Li Liu
- Center of Drug Metabolism and Pharmacokinetics, College of Pharmacy, China Pharmaceutical University Nanjing, China
| | - Xiao-Dong Liu
- Center of Drug Metabolism and Pharmacokinetics, College of Pharmacy, China Pharmaceutical University Nanjing, China
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15
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Nunes AR, Alves MG, Moreira PI, Oliveira PF, Silva BM. Can Tea Consumption be a Safe and Effective Therapy Against Diabetes Mellitus-Induced Neurodegeneration? Curr Neuropharmacol 2014; 12:475-89. [PMID: 25977676 PMCID: PMC4428023 DOI: 10.2174/1570159x13666141204220539] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 10/10/2014] [Accepted: 12/03/2014] [Indexed: 12/20/2022] Open
Abstract
Diabetes mellitus (DM) is a metabolic disease that is rapidly increasing and has become a major public health problem. Type 2 DM (T2DM) is the most common type, accounting for up to 90-95% of the new diagnosed DM cases. The brain is very susceptible to glucose fluctuations and hyperglycemia-induced oxidative stress (OS). It is well known that DM and the risk of developing neurodegenerative diseases are associated. Tea, Camellia sinensis L., is one of the most consumed beverages. It contains several phytochemicals, such as polyphenols, methylxanthines (mainly caffeine) and L-theanine that are often reported to be responsible for tea's health benefits, including in brain. Tea phytochemicals have been reported to be responsible for tea's significant antidiabetic and neuroprotective properties and antioxidant potential. Epidemiological studies have shown that regular consumption of tea has positive effects on DM-caused complications and protects the brain against oxidative damage, contributing to an improvement of the cognitive function. Among the several reported benefits of tea consumption, those related with neurodegenerative diseases are of great interest. Herein, we discuss the potential beneficial effects of tea consumption and tea phytochemicals on DM and how their action can counteract the severe brain damage induced by this disease.
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Affiliation(s)
- Ana R. Nunes
- CICS – UBI – Health Sciences Research Centre, University of Beira Interior, 6201-506 Covilhã, Portugal
| | - Marco G. Alves
- CICS – UBI – Health Sciences Research Centre, University of Beira Interior, 6201-506 Covilhã, Portugal
| | - Paula I. Moreira
- CNC – Center for Neuroscience and Cell Biology, University of Coimbra and Laboratory of Physiology, Faculty of Medicine, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Pedro F. Oliveira
- CICS – UBI – Health Sciences Research Centre, University of Beira Interior, 6201-506 Covilhã, Portugal
| | - Branca M. Silva
- CICS – UBI – Health Sciences Research Centre, University of Beira Interior, 6201-506 Covilhã, Portugal
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Sun YN, Liu LB, Xue YX, Wang P. Effects of insulin combined with idebenone on blood-brain barrier permeability in diabetic rats. J Neurosci Res 2014; 93:666-77. [PMID: 25421718 DOI: 10.1002/jnr.23511] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/26/2014] [Accepted: 09/30/2014] [Indexed: 11/07/2022]
Abstract
This study investigates the effect of insulin combined with idebenone on blood-brain barrier (BBB) permeability in experimental streptozotocin-induced diabetic rats as well as the underlying mechanisms. With a diabetic rat model, we show that insulin and idebenone normalize body weight and water intake and restore BBB permeability and that their combination displays a synergistic effect. The results from transmission electron microscopy show that the combination of insulin and idebenone significantly closed the tight junction (TJ) in diabetic rats. The results from Western blotting in diabetic rats show that the upregulation of TJ-associated proteins occludin, and zonula occludens (ZO)-1 caused by the combination of insulin and idebenone is more remarkable than that with either agent alone. In addition, the activations of reactive oxygen species (ROS) and advanced glycation end products (AGEs) and the expression levels of receptors for advanced glycation end-products (RAGE) and nuclear factor-κB (NF-κB) were significantly decreased after treatment with insulin and idebenone in diabetic rats. These results suggest that the combination of insulin and idebenone could decrease the BBB permeability in diabetic rats by upregulating the expression of occludin, claudin-5, and ZO-1 and that the ROS/AGE/RAGE/NF-κB signal pathway might be involved in the process.
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Affiliation(s)
- Yan-Na Sun
- Department of Neurobiology, College of Basic Medicine, and Institute of Pathology and Pathophysiology, China Medical University, Shenyang, People's Republic of China
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Aggarwal A, Khera A, Singh I, Sandhir R. S-nitrosoglutathione prevents blood-brain barrier disruption associated with increased matrix metalloproteinase-9 activity in experimental diabetes. J Neurochem 2014; 132:595-608. [PMID: 25187090 DOI: 10.1111/jnc.12939] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 08/10/2014] [Accepted: 08/20/2014] [Indexed: 12/14/2022]
Abstract
Hyperglycemia is known to induce microvascular complications, thereby altering blood-brain barrier (BBB) permeability. This study investigated the role of matrix metalloproteinases (MMPs) and their endogenous inhibitors in increased BBB permeability and evaluated the protective effect of S-nitrosoglutathione (GSNO) in diabetes. Diabetes was induced in mice by intraperitoneal injection of streptozotocin (40 mg/kg body weight) for 5 days and GSNO was administered orally (100 μg/kg body weight) daily for 8 weeks after the induction of diabetes. A significant decline in cognitive functions was observed in diabetic mice assessed by Morris water maze test. Increased permeability to different molecular size tracers accompanied by edema and ion imbalance was observed in cortex and hippocampus of diabetic mice. Furthermore, activity of both pro and active MMP-9 was found to be significantly elevated in diabetic animals. Increased in situ gelatinase activity was observed in tissue sections and isolated microvessels from diabetic mice brain. The increase in activity of MMP-9 was attributed to increased mRNA and protein expression in diabetic mice. In addition, a significant decrease in mRNA and protein expression of tissue inhibitor of matrix metalloproteinase-1 was also observed in diabetic animals. However, GSNO supplementation to diabetic animals was able to abridge MMP-9 activation as well as tissue inhibitor of matrix metalloproteinase-1 levels, restoring BBB integrity and also improving learning and memory. Our findings clearly suggest that GSNO could prevent hyperglycemia-induced disruption of BBB by suppressing MMP-9 activity.
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Affiliation(s)
- Aanchal Aggarwal
- Department of Biochemistry, Basic Medical Science Building, Panjab University, Chandigarh, India
| | - Alka Khera
- Department of Biochemistry, Basic Medical Science Building, Panjab University, Chandigarh, India
| | - Inderjit Singh
- Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Rajat Sandhir
- Department of Biochemistry, Basic Medical Science Building, Panjab University, Chandigarh, India
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Sajja RK, Prasad S, Cucullo L. Impact of altered glycaemia on blood-brain barrier endothelium: an in vitro study using the hCMEC/D3 cell line. Fluids Barriers CNS 2014; 11:8. [PMID: 24708805 PMCID: PMC3985548 DOI: 10.1186/2045-8118-11-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 03/17/2014] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Cerebrovascular complications involving endothelial dysfunction at the blood-brain barrier (BBB) are central to the pathogenesis of diabetes-related CNS disorders. However, clinical and experimental studies have reported contrasting evidence in relation to the effects of hyperglycemia on BBB permeability and function. Similarly the effect of hypoglycemia on BBB integrity is not well understood. Therefore, we assessed the differential impact of hypo and hyperglycemic conditions on BBB integrity and endothelial function in vitro using hCMEC/D3, a well characterized human brain microvascular endothelial cell line. METHODS Parallel monolayers of hCMEC/D3 were exposed to normal, hypo- or hyperglycemic media, containing 5.5, 2.2 or 35 mM D-glucose, respectively. Following 3-24h exposure, the expression and distribution of BBB tight junction (ZO-1 and claudin-5) adherence junction (VE-cadherin) proteins, and glucose transporters as well as inflammatory (VCAM-1) and oxidative stress (Nrf-2) markers were analyzed by immunofluorescence and western blotting. Endothelial release of growth factors and pro-inflammatory cytokines were determined by ELISA. Further, the impact of altered glycemia on BBB permeability was assessed in hCMEC/D3 - astrocyte co-cultures on Transwell supports using fluorescent dextrans (4-70 kDa). RESULTS Compared to controls, exposure to hypoglycemia (3 and 24h) down-regulated the expression of claudin-5 and disrupted the ZO-1 localization at cell-cell contacts, while hyperglycemia marginally reduced claudin-5 expression without affecting ZO-1 distribution. Permeability to dextrans (4-10 kDa) and VEGF release at 24h were significantly increased by hypo- and hyperglycemia, although 70 kDa dextran permeability was increased only under hypoglycemic conditions. The expression of SGLT-1 was up-regulated at 24h hypoglycemic exposure while only a modest increase of GLUT-1 expression was observed. In addition, the expression of Nrf-2 and release of interleukin-6 and PDGF-BB, were down-regulated by hypoglycemia (but not hyperglycemia), while both conditions induced a marginal and transient increase in VCAM-1 expression from 3 to 24h, including a significant increase in VE-cadherin expression at 3 h following hyperglycemia. CONCLUSIONS In summary, our findings demonstrate a potential impairment of BBB integrity and function by hypo or hyperglycemia, through altered expression/distribution of TJ proteins and nutrient transporters. In addition, hypoglycemic exposure severely affects the expression of oxidative and inflammatory stress markers of BBB endothelium.
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Affiliation(s)
| | | | - Luca Cucullo
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health Sciences Center, 1300 S, Coulter Street, Amarillo, TX 79106, USA.
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Bloemer J, Bhattacharya S, Amin R, Suppiramaniam V. Impaired insulin signaling and mechanisms of memory loss. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 121:413-49. [PMID: 24373245 DOI: 10.1016/b978-0-12-800101-1.00013-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Insulin is secreted from the β-cells of the pancreas and helps maintain glucose homeostasis. Although secreted peripherally, insulin also plays a profound role in cognitive function. Increasing evidence suggests that insulin signaling in the brain is necessary to maintain health of neuronal cells, promote learning and memory, decrease oxidative stress, and ultimately increase neuronal survival. This chapter summarizes the different facets of insulin signaling necessary for learning and memory and additionally explores the association between cognitive impairment and central insulin resistance. The role of impaired insulin signaling in the advancement of cognitive dysfunction is relevant to the current debate of whether the shared pathophysiological mechanisms between diabetes and cognitive impairment implicate a direct relationship. Here, we summarize a vast amount of literature that suggests a strong association between impaired brain insulin signaling and cognitive impairment.
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Affiliation(s)
- Jenna Bloemer
- Department of Pharmacal Sciences, Harrison School of Pharmacy, Auburn University, Auburn, Alabama, USA
| | - Subhrajit Bhattacharya
- Department of Pharmacal Sciences, Harrison School of Pharmacy, Auburn University, Auburn, Alabama, USA
| | - Rajesh Amin
- Department of Pharmacal Sciences, Harrison School of Pharmacy, Auburn University, Auburn, Alabama, USA
| | - Vishnu Suppiramaniam
- Department of Pharmacal Sciences, Harrison School of Pharmacy, Auburn University, Auburn, Alabama, USA
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Ma LY, Zhang DM, Tang Y, Lu Y, Zhang Y, Gao Y, Xia L, Zhao KX, Chai LY, Xiao Q. Ghrelin-attenuated cognitive dysfunction in streptozotocin-induced diabetic rats. Alzheimer Dis Assoc Disord 2012; 25:352-63. [PMID: 22005105 DOI: 10.1097/wad.0b013e31820ce536] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Diabetic encephalopathy is clinically characterized by acquired behavior and cognitive dysfunction but its pathogenesis is not clear. This study aimed to explore the pathogenesis of diabetic encephalopathy and the mechanisms of ghrelin to ameliorate cognitive dysfunction in diabetic rats. Thirty-six streptozotocin diabetic rat models were established; 12 weeks later, all the rats were randomly divided into 3 groups [diabetic model group (D), ghrelin treatment group (T1), and ghrelin and D-lys-3-GHRP-6 treatment group (T2)] of 12 each. Twelve normoglycemic rats were classified in the normal group (N). Learning and memory behaviors were measured using a spatial version of the Morris water maze test. The brain-derived neurotrophic factor (BDNF), cAMP responsive element binding protein (CREB), phosphorylated CREB (p-CREB), phosphorylated ERK1/2 (p-ERK1/2), caspase-3, and Bcl-xl protein expressions in the hippocampi of all the rats were detected using immunohistochemistry. The mRNA expressions of BDNF, CREB, and caspase-3 were examined using reverse transcription-polymerase chain reaction. The hippocampus neuronal apoptosis was measured by terminal deoxynucleotidyl transferase dUTP nick end labeling method. We found that learning and memory level in the ghrelin treatment group improved significantly, expression of Bcl-xl, BDNF, CREB, p-CREB, and p-ERK1/2 in the hippocampus was increased in the ghrelin treatment group, and the number of apoptotic neurons in the hippocampus decreased remarkably. Our results showed that the changes of BDNF, CREB, and hippocampus neuronal apoptosis might be involved in the pathogenesis of diabetic encephalopathy. We suggested that ghrelin improved cognitive ability in streptozotocin-induced diabetic rats by improving the expressions of BDNF and CREB and by attenuating hippocampus neuronal apoptosis. The effects of ghrelin depend on the receptor of ghrelin, GHSR-1a, and ERK1/2 pathway.
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Affiliation(s)
- Lou-yan Ma
- Department of Geriatrics, the First Affiliated Hospital, Chongqing Medical University, China
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21
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Arden GB, Sivaprasad S. The pathogenesis of early retinal changes of diabetic retinopathy. Doc Ophthalmol 2012; 124:15-26. [PMID: 22302291 DOI: 10.1007/s10633-011-9305-y] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 12/14/2011] [Indexed: 01/04/2023]
Abstract
Recent successful trials of antibodies to vascular endothelial growth factor (VEGF) in diabetic retinopathy implicate this cytokine as a major cause of diabetic retinopathy (DR) and diabetic macular oedema (DME). The mechanisms which cause VEGF to be over-expressed to cause the vasculopathy are not entirely clear. This review explores the earliest changes to the retina in DR and the factors that predispose or prevent DR, including sleep apnoea, receptor degenerations laser treatment and VEGF polymorphism. The review also presents the evidence that retinal hypoxia, existing in the earliest stages, causes DR. This hypoxia is much increased by dark adaptation, indicating a new and possibly superior therapy.
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22
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Mogi M, Horiuchi M. Neurovascular coupling in cognitive impairment associated with diabetes mellitus. Circ J 2011; 75:1042-8. [PMID: 21441696 DOI: 10.1253/circj.cj-11-0121] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although it is feared that diabetes-induced cognitive decline will become a major clinical problem worldwide in the future, the detailed pathological mechanism is not well known. Because patients with diabetes have various complications of vascular disease, with not only macrovascular but also microvascular disorders, vascular disorders in the brain are considered to be one of the mechanisms in diabetes-induced cognitive impairment. Indeed, disruption of the blood-brain barrier (BBB) has been observed in some diabetic patients and experimental diabetes models. Moreover, white matter lesions, part of the evidence of BBB dysfunction, are reported to be observed more frequently in patients with diabetes. Animal studies demonstrate that diabetes enhances BBB permeability through a decrease in the level of tight junction proteins and an increase in matrix metalloproteinase activity. However, there are several reports indicating that BBB disruption does not occur with diabetes. Therefore, the association of BBB breakdown with diabetes-induced cognitive impairment is not conclusive. Recently, neuronal diseases involving dementia have been induced experimentally through dysfunction of neurovascular coupling, which involves blood vessels, astrocytes and neutrons. Diabetes-induced cognitive decline may be induced via disruption of neurovascular coupling, with not only vascular disorder but also impairment of astrocytic trafficking. Here, the relation between vascular disorder and cognitive impairment in diabetes is discussed.
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Affiliation(s)
- Masaki Mogi
- Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Graduate School of Medicine, Tohon, Japan.
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Vascular pathology and blood-brain barrier disruption in cognitive and psychiatric complications of type 2 diabetes mellitus. Cardiovasc Psychiatry Neurol 2011; 2011:609202. [PMID: 21350721 PMCID: PMC3042607 DOI: 10.1155/2011/609202] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 12/28/2010] [Indexed: 01/13/2023] Open
Abstract
Vascular pathology is recognized as a principle insult in type 2 diabetes mellitus (T2DM). Co-morbidities such as structural brain abnormalities, cognitive, learning and memory deficits are also prevailing in T2DM patients. We previously suggested that microvascular pathologies involving blood-brain barrier (BBB) breakdown results in leakage of serum-derived components into the brain parenchyma, leading to neuronal dysfunction manifested as psychiatric illnesses. The current postulate focuses on the molecular mechanisms controlling BBB permeability in T2DM, as key contributors to the pathogenesis of mental disorders in patients. Revealing the mechanisms underlying BBB dysfunction and inflammatory response in T2DM and their role in metabolic disturbances, abnormal neurovascular coupling and neuronal plasticity, would contribute to the understanding of the mechanisms underlying psychopathologies in diabetic patients. Establishing this link would offer new targets for future therapeutic interventions.
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Reichel V, Burghard S, John I, Huber O. P-glycoprotein and breast cancer resistance protein expression and function at the blood-brain barrier and blood-cerebrospinal fluid barrier (choroid plexus) in streptozotocin-induced diabetes in rats. Brain Res 2010; 1370:238-45. [PMID: 21075088 DOI: 10.1016/j.brainres.2010.11.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 11/02/2010] [Accepted: 11/05/2010] [Indexed: 10/18/2022]
Abstract
The aim of the study was to investigate the influence of diabetes mellitus type 1 on expression and function of the ATP-binding cassette transport proteins P-glycoprotein (Pgp, Abcb1) and breast cancer resistance protein (Bcrp, Abcg2) at the blood-brain barrier and the blood-cerebrospinal fluid barrier formed by the choroid plexus. In brain capillary endothelial cells forming the blood-brain barrier, Pgp and Bcrp are located in the luminal membrane while apical/sub-apical localization was described for Pgp in choroid plexus epithelial cells. Alterations in expression or function may lead to damages in barrier integrity and may cause brain defects after long term diabetes. Diabetes was induced by i.p.-streptozotocin injection 14days prior to performing experiments. RNA and protein expression were analyzed in choroid plexus and blood-brain barrier capillaries by RT-PCR and Western blot, respectively. Pgp and Bcrp expression was increased in blood-brain barrier capillaries; in choroid plexus, only Bcrp showed elevated gene expression. Protein expression was not altered. Functional analyses were carried out using confocal laser-scanning microscopy in intact isolated brain capillaries with the fluorescent Pgp substrate NBD-Cyclosporin A (NBD-CsA) and BODIPY® FL prazosin as substrate for Bcrp. Consistent with protein expression data, no changes in diabetic animals occurred, suggesting an unaltered function of Pgp and Bcrp.
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Affiliation(s)
- Valeska Reichel
- Department Pharmaceutical Technology and Biopharmacy, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany.
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Hawkins RA, Mokashi A, Dejoseph MR, Viña JR, Fernstrom JD. Glutamate permeability at the blood-brain barrier in insulinopenic and insulin-resistant rats. Metabolism 2010; 59:258-66. [PMID: 19793593 PMCID: PMC2813370 DOI: 10.1016/j.metabol.2009.07.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Revised: 05/29/2009] [Accepted: 07/24/2009] [Indexed: 02/07/2023]
Abstract
The influence of diabetes on brain glutamate (GLU) uptake was studied in insulinopenic (streptozotocin [STZ]) and insulin-resistant (diet-induced obesity [DIO]) rat models of diabetes. In the STZ study, adult male Sprague-Dawley rats were treated with STZ (65 mg/kg intravenously) or vehicle and studied 3 weeks later. The STZ rats had elevated plasma levels of glucose, ketone bodies, and branched-chain amino acids; brain uptake of GLU was very low in both STZ and control rats, examined under conditions of normal and greatly elevated (by intravenous infusion) plasma GLU concentrations. In the DIO study, rats ingested a palatable, high-energy diet for 2 weeks and were then divided into weight tertiles: rats in the heaviest tertile were designated DIO; rats in the lightest tertile, diet-resistant (DR); and rats in the intermediate tertile, controls. The DIO and DR rats continued to consume the high-energy diet for 4 more weeks, whereas the control rats were switched to standard rat chow. All rats were studied at 6 weeks (subgroups were examined under conditions of normal or elevated plasma GLU concentrations). The DIO rats ate more food and were heavier than the DR or control rats and had higher plasma leptin levels and insulin-glucose ratios. In all diet groups, the blood-brain barrier showed very low GLU penetration and was unaffected by plasma GLU concentration. Brain GLU uptake also did not differ among the diet groups. Together, the results indicate that the blood-brain barrier remains intact to the penetration of GLU in 2 models of diabetes under the conditions examined.
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Affiliation(s)
- Richard A Hawkins
- Department of Physiology and Biophysics, The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064-3095, USA.
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Guven A, Yavuz O, Cam M, Comunoglu C, Sevi'nc O. Central nervous system complications of diabetes in streptozotocin-induced diabetic rats: a histopathological and immunohistochemical examination. Int J Neurosci 2010; 119:1155-69. [PMID: 19922346 DOI: 10.1080/00207450902841723] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Diabetes mellitus is a common, potentially serious metabolic disorder. Over the long term, diabetes leads to serious consequences in a number of tissues, especially those that are insulin insensitive (retina, neurons, kidneys). It also causes a variety of functional and structural disorders in the central and peripheral nervous systems. We investigated whether neurodegenerative changes were observable in the hippocampus, cortex, and cerebellum after 4 weeks of streptozotocin (STZ)-induced diabetes in rats and the effect(s) of melatonin. Male Wistar rats (n = 32) were divided into four groups (n = 8 each): untreated controls, melatonin-treated controls, untreated diabetics, and melatonin-treated diabetics. Experimental diabetes was induced by a single dose of STZ (60 mg/kg, intraperitoneal (ip)). For 3 days before the administration of STZ, melatonin (200 microg/kg/day, ip) was injected and continued for 4 weeks. Sections of hippocampus, cortex, and cerebellum were stained with hematoxylin and eosin and examined using light microscopy. In addition, brain tissues were examined immunohistochemically for the expression of glial and neuronal markers, including glial fibrillary acidic protein (GFAP), neuron-specific enolase (NSE), and heat shock protein-70 (HSP-70). No neurodegenerative changes were observed in the hippocampus, cortex, or cerebellum of the untreated diabetic group after 4 weeks compared with the other groups. We did not observe any change in GFAP, NSE, or HSP-70 immunostaining in the brain tissues of STZ-induced diabetic rats. In summary, after 4 weeks of STZ-induced diabetes in rats, no degenerative or immunohistochemical changes were detected in the hippocampus, cortex, or cerebellum.
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Affiliation(s)
- Aysel Guven
- Department of Histology and Embryology, Canakkale Onsekiz Mart University School of Medicine, Canakkale, Turkey.
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Klaassen I, Hughes JM, Vogels IM, Schalkwijk CG, Van Noorden CJ, Schlingemann RO. Altered expression of genes related to blood–retina barrier disruption in streptozotocin-induced diabetes. Exp Eye Res 2009; 89:4-15. [DOI: 10.1016/j.exer.2009.01.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 10/31/2008] [Accepted: 01/12/2009] [Indexed: 11/28/2022]
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28
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Liu YC, Liu HY, Yang HW, Wen T, Shang Y, Liu XD, Xie L, Wang GJ. Impaired expression and function of breast cancer resistance protein (Bcrp) in brain cortex of streptozocin-induced diabetic rats. Biochem Pharmacol 2007; 74:1766-72. [PMID: 17915193 DOI: 10.1016/j.bcp.2007.08.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 08/16/2007] [Accepted: 08/16/2007] [Indexed: 01/16/2023]
Abstract
The aim of this study was to investigate whether diabetes mellitus (DM) affected breast cancer resistance protein (Bcrp) function and expression in rat brain. 5-week and 8-week diabetic rats were induced by streptozocin (STZ). Bcrp expression and function in brain cortex were assessed by western blot and measuring the brain-to-plasma concentration ratios of two typical substrates prazosin and cimetidine, respectively. The diabetic rats were treated with three different agents insulin, aminoguanidine (AG) and metformin (MET). It was found that the brain-to-plasma ratios of prazosin and cimetidine in diabetic rats were significantly higher than those of control rats, which were dependent on duration of diabetes. Lower levels of Bcrp were found in brain cortex of diabetic rats, which were in parallel with increase of brain-to-plasma ratios. Insulin treatment may attenuate the impairment of Bcrp expression and function induced by diabetes. Aminoguanidine and metformin treatment did not prevent the impairment of Bcrp function and expression in brain cortex of diabetic rats. All results gave a conclusion that STZ-induced DM may induce the impairment of function and expression of Bcrp in brain cortex, and lower levels of insulin may mainly contribute to Bcrp dysfunction in brain.
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Affiliation(s)
- Yu-Chun Liu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Tongjiaxiang No. 24, Nanjing 210009, China
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Liu H, Zhang D, Xu X, Liu X, Wang G, Xie L, Pang X, Liu L. Attenuated function and expression of P-glycoprotein at blood-brain barrier and increased brain distribution of phenobarbital in streptozotocin-induced diabetic mice. Eur J Pharmacol 2007; 561:226-32. [PMID: 17349620 DOI: 10.1016/j.ejphar.2007.01.062] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2006] [Revised: 01/17/2007] [Accepted: 01/17/2007] [Indexed: 11/26/2022]
Abstract
The aim of the study was to investigate whether diabetes mellitus modulated the function and expression of P-glycoprotein and the distribution of phenobarbital in the brain of 3-week streptozotocin-induced diabetic mice. P-glycoprotein function in blood-brain barrier was assessed by measuring the brain-to-plasma concentration ratios of rodamine123, a well-known P-glycoprotein substrate, in non-diabetic mice and diabetic mice. P-glycoprotein expression in the brain cortex was evaluated with western blot. Whether diabetes mellitus changed the distribution of phenobarbital (60 mg/kg, i.v.) in brain of mice was measured, and whether the changed distribution caused the difference of phenobarbital (80 and 100 mg/kg) -induced loss of the righting reflex in non-diabetic and diabetic mice were also investigated. The results showed that the brain-to-plasma concentration ratio value of rodamine123 in diabetic mice was significantly higher than that of non-diabetic mice, western blot suggested that the protein level of P-glycoprotein in the brain of 3-week diabetic mice was significantly lower than that of non-diabetic mice, and insulin treatment restored the impairment of P-glycoprotein. The exposure of phenobarbital in brain of diabetic mice was 1.30-fold of that of non-diabetic mice, while in plasma the fold was 1.09. The increased distribution of phenobarbital in the brain of diabetic mice significantly increased the duration of phenobarbital-induced loss of the righting reflex and reduced the latency time of loss of the righting reflex. All the results suggested that the function and expression of P-glycoprotein might be impaired and the brain distribution of phenobarbital was increased in brain of streptozotocin-induced diabetic mice.
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Affiliation(s)
- HaiYan Liu
- Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing 210009, China
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Hawkins BT, Ocheltree SM, Norwood KM, Egleton RD. Decreased blood-brain barrier permeability to fluorescein in streptozotocin-treated rats. Neurosci Lett 2007; 411:1-5. [PMID: 17110033 PMCID: PMC1785293 DOI: 10.1016/j.neulet.2006.09.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 09/01/2006] [Accepted: 09/06/2006] [Indexed: 01/01/2023]
Abstract
Investigations of the blood-brain barrier (BBB) in diabetes have yielded contradictory results. It is possible that diabetes differentially affects paracellular and transcellular permeabilities via modulation of tight junction and transport proteins, respectively. Fluorescein (FL), a marker for paracellular permeability, is a substrate for the transport proteins organic anion transporter (OAT)-3 and multidrug resistance protein (MRP)-2 at the BBB. Furthermore, MRP-2-mediated efflux of FL can be upregulated by glucose. In this study, streptozotocin-induced diabetes led to decreased brain distribution of FL measured by in situ brain perfusion, consistent with activation of an efflux transport system for FL at the BBB. This change was paralleled by increased protein expression of MRP-2, but not OAT-3, in cerebral microvessels. These data indicate that diabetes may lead to changes in efflux transporters at the BBB and have implications for delivery of therapeutics to the central nervous system.
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Affiliation(s)
- Brian T. Hawkins
- Department of Medical Pharmacology, The University of Arizona College of Medicine, Tucson, AZ 85724
| | - Scott M. Ocheltree
- Department of Medical Pharmacology, The University of Arizona College of Medicine, Tucson, AZ 85724
| | - Kristi M. Norwood
- Department of Medical Pharmacology, The University of Arizona College of Medicine, Tucson, AZ 85724
| | - Richard D. Egleton
- Department of Medical Pharmacology, The University of Arizona College of Medicine, Tucson, AZ 85724
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Hawkins BT, Lundeen TF, Norwood KM, Brooks HL, Egleton RD. Increased blood-brain barrier permeability and altered tight junctions in experimental diabetes in the rat: contribution of hyperglycaemia and matrix metalloproteinases. Diabetologia 2007; 50:202-11. [PMID: 17143608 DOI: 10.1007/s00125-006-0485-z] [Citation(s) in RCA: 240] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Accepted: 09/14/2006] [Indexed: 11/26/2022]
Abstract
AIMS/HYPOTHESIS Although diabetes mellitus is associated with peripheral microvascular complications and increased risk of neurological events, the mechanisms by which diabetes disrupts the blood-brain barrier (BBB) are not known. Matrix metalloproteinase (MMP) activity is increased in diabetic patients, is associated with degradation of tight junction proteins, and is a known mediator of BBB compromise. We hypothesise that diabetes leads to compromise of BBB tight junctions via stimulation of MMP activity. MATERIALS AND METHODS Diabetes was induced in the rat with streptozotocin. At 14 days after injection, BBB function was assessed by in situ brain perfusion. Tight junction proteins were assessed by immunoblot and immunofluorescence. Plasma MMP activity was quantified by fluorometric gelatinase assay and gel zymography. RESULTS In streptozotocin-treated animals, permeability to [(14)C]sucrose increased concurrently with decreased production of BBB tight junction proteins occludin (also known as OCLN) and zona occludens 1 (ZO-1, also known as tight junction protein 1 or TJP1). Insulin treatment, begun on day 7, normalised blood glucose levels and attenuated BBB hyperpermeability to [(14)C]sucrose. Neither acute hyperglycaemia in naive animals nor acute normalisation of blood glucose in streptozotocin-treated animals altered BBB permeability to [(14)C]sucrose. Plasma MMP activity was increased in streptozotocin-treated animals. CONCLUSIONS/INTERPRETATION These data indicate that diabetes increases BBB permeability via a loss of tight junction proteins, and that increased BBB permeability in diabetes does not result from hyperglycaemia alone. Increased plasma MMP activity is implicated in degradation of BBB tight junction proteins and increased BBB permeability in diabetes. Peripheral MMP activity may present a novel target for protection of the BBB and prevention of neurological complications in diabetes.
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Affiliation(s)
- B T Hawkins
- Department of Medical Pharmacology, The University of Arizona College of Medicine, 1501 N. Campbell Ave., P.O. Box 245050, Tucson, AZ 85724-5050, USA
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Lim MJ, Alexander N, Benedict JW, Chattopadhyay S, Shemilt SJA, Guérin CJ, Cooper JD, Pearce DA. IgG entry and deposition are components of the neuroimmune response in Batten disease. Neurobiol Dis 2006; 25:239-51. [PMID: 17070688 DOI: 10.1016/j.nbd.2006.09.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Revised: 08/31/2006] [Accepted: 09/07/2006] [Indexed: 11/30/2022] Open
Abstract
Patients and a mouse model of Batten disease, the juvenile form of neuronal ceroid lipofuscinosis (JNCL), raise autoantibodies against GAD65 and other brain-directed antigens. Here we investigate the adaptive component of the neuroimmune response. Cln3(-/-) mice have autoantibodies to GAD65 in their cerebrospinal fluid and elevated levels of brain bound immunoglobulin G (IgG). IgG deposition was found within human JNCL autopsy material, a feature that became more evident with increased age in Cln3(-/-) mice. The lymphocyte infiltration present in human and murine JNCL occurred late in disease progression, and was not capable of central/intrathecal IgG production. In contrast, we found evidence for an early systemic immune dysregulation in Cln3(-/-) mice. In addition evidence for a size-selective breach in the blood-brain barrier integrity in these mice suggests that systemically produced autoantibodies can access the JNCL central nervous system and contribute to a progressive inflammatory response.
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Affiliation(s)
- Ming J Lim
- Pediatric Storage Disorders Laboratory, Department of Neuroscience and Centre for the Cellular Basis of Behaviour, Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, UK
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Kamei J, Hirano S, Miyata S, Saitoh A, Onodera K. Effects of First- and Second-Generation Histamine-H1-Receptor Antagonists on the Pentobarbital-Induced Loss of the Righting Reflex in Streptozotocin-Induced Diabetic Mice. J Pharmacol Sci 2005; 97:266-72. [PMID: 15699576 DOI: 10.1254/jphs.fp0040832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The second-generation histamine-H(1)-receptor antagonists, such as epinastine and cetirizine, are used as non-sedating antihistamines for treating allergic symptoms due to their poor ability to penetrate blood-brain barrier. Because it has been reported that the blood-brain barrier system is disturbed in diabetes, it is possible that second-generation histamine-H(1)-receptor antagonists may easily penetrate the blood-brain barrier and cause potent sedation in diabetics. In the present study, we investigated the effects of first-generation (diphenhydramine) and second-generation (epinastine and cetirizine) histamine-H(1)-receptor antagonists on the duration of pentobarbital-induced loss of the righting reflex (LORR) in non-diabetic and diabetic mice. Systemic treatment with diphenhydramine (3 - 30 mg/kg, s.c.), and intracerebroventricular treatment with epinastine (0.03 - 0.3 microg/mouse) and cetirizine (0.03 - 0.3 microg/mouse) dose-dependently and significantly increased the duration of pentobarbital-induced LORR in both non-diabetic and diabetic mice. Although systemic treatment with epinastine (3 - 30 mg/kg, s.c.) and cetirizine (3 - 30 mg/kg, s.c.) did not affect the duration of pentobarbital-induced LORR in non-diabetic mice, these treatments significantly prolonged it in diabetic mice. Our results suggest that the systemic administration of second-generation histamine-H(1)-receptor antagonists may produce a central nervous system depressant effect in diabetes.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily B, Member 1/biosynthesis
- Animals
- Brain/metabolism
- Brain/physiopathology
- Central Nervous System Depressants/pharmacology
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/physiopathology
- Diabetic Neuropathies/metabolism
- Diabetic Neuropathies/physiopathology
- Dose-Response Relationship, Drug
- Histamine H1 Antagonists/pharmacology
- Histamine H1 Antagonists, Non-Sedating/pharmacology
- Male
- Mice
- Mice, Inbred ICR
- Pentobarbital/toxicity
- Postural Balance/drug effects
- Postural Balance/physiology
- Receptors, Histamine H1/physiology
- Reflex/drug effects
- Reflex/physiology
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Affiliation(s)
- Junzo Kamei
- Department of Pathophysiology and Therapeutics, School of Pharmacy and Pharmaceutical Sciences, Hoshi University, Tokyo, Japan.
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Baggio LL, Huang Q, Brown TJ, Drucker DJ. A recombinant human glucagon-like peptide (GLP)-1-albumin protein (albugon) mimics peptidergic activation of GLP-1 receptor-dependent pathways coupled with satiety, gastrointestinal motility, and glucose homeostasis. Diabetes 2004; 53:2492-500. [PMID: 15331566 DOI: 10.2337/diabetes.53.9.2492] [Citation(s) in RCA: 289] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Peptide hormones exert unique actions via specific G protein-coupled receptors; however, the therapeutic potential of regulatory peptides is frequently compromised by rapid enzymatic inactivation and clearance from the circulation. In contrast, recombinant or covalent coupling of smaller peptides to serum albumin represents an emerging strategy for extending the circulating t(1/2) of the target peptide. However, whether larger peptide-albumin derivatives will exhibit the full spectrum of biological activities encompassed by the native peptide remains to be demonstrated. We report that Albugon, a human glucagon-like peptide (GLP)-1-albumin recombinant protein, activates GLP-1 receptor (GLP-1R)-dependent cAMP formation in BHK-GLP-1R cells, albeit with a reduced half-maximal concentration (EC(50)) (0.2 vs. 20 nmol/l) relative to the GLP-1R agonist exendin-4. Albugon decreased glycemic excursion and stimulated insulin secretion in wild-type but not GLP-1R(-/-) mice and reduced food intake after both intracerebroventricular and intraperitoneal administration. Moreover, intraperitoneal injection of Albugon inhibited gastric emptying and activated c-FOS expression in the area postrema, the nucleus of the solitary tract, the central nucleus of the amygdala, the parabrachial, and the paraventricular nuclei. These findings illustrate that peripheral administration of a larger peptide-albumin recombinant protein mimics GLP-1R-dependent activation of central and peripheral pathways regulating energy intake and glucose homeostasis in vivo.
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Affiliation(s)
- Laurie L Baggio
- Toronto General Hospital, Banting and Best Diabetes Centre, 200 Elizabeth St., MBRW4R-402, Toronto, Canada
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