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Romero-Martínez BS, Sommer B, Solís-Chagoyán H, Calixto E, Aquino-Gálvez A, Jaimez R, Gomez-Verjan JC, González-Avila G, Flores-Soto E, Montaño LM. Estrogenic Modulation of Ionic Channels, Pumps and Exchangers in Airway Smooth Muscle. Int J Mol Sci 2023; 24:ijms24097879. [PMID: 37175587 PMCID: PMC10178541 DOI: 10.3390/ijms24097879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 02/28/2023] [Accepted: 02/28/2023] [Indexed: 05/15/2023] Open
Abstract
To preserve ionic homeostasis (primarily Ca2+, K+, Na+, and Cl-), in the airway smooth muscle (ASM) numerous transporters (channels, exchangers, and pumps) regulate the influx and efflux of these ions. Many of intracellular processes depend on continuous ionic permeation, including exocytosis, contraction, metabolism, transcription, fecundation, proliferation, and apoptosis. These mechanisms are precisely regulated, for instance, through hormonal activity. The lipophilic nature of steroidal hormones allows their free transit into the cell where, in most cases, they occupy their cognate receptor to generate genomic actions. In the sense, estrogens can stimulate development, proliferation, migration, and survival of target cells, including in lung physiology. Non-genomic actions on the other hand do not imply estrogen's intracellular receptor occupation, nor do they initiate transcription and are mostly immediate to the stimulus. Among estrogen's non genomic responses regulation of calcium homeostasis and contraction and relaxation processes play paramount roles in ASM. On the other hand, disruption of calcium homeostasis has been closely associated with some ASM pathological mechanism. Thus, this paper intends to summarize the effects of estrogen on ionic handling proteins in ASM. The considerable diversity, range and power of estrogens regulates ionic homeostasis through genomic and non-genomic mechanisms.
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Affiliation(s)
- Bianca S Romero-Martínez
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Bettina Sommer
- Laboratorio de Hiperreactividad Bronquial, Instituto Nacional de Enfermedades Respiratorias "Ismael Cosío Villegas", Ciudad de México 14080, Mexico
| | - Héctor Solís-Chagoyán
- Neurociencia Cognitiva Evolutiva, Centro de Investigación en Ciencias Cognitivas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico
| | - Eduardo Calixto
- Departamento de Neurobiología, Dirección de Investigación en Neurociencias, Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñiz", Ciudad de México 14370, Mexico
| | - Arnoldo Aquino-Gálvez
- Laboratorio de Biología Molecular, Departamento de Fibrosis Pulmonar, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, México City 14080, Mexico
| | - Ruth Jaimez
- Laboratorio de Estrógenos y Hemostasis, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Juan C Gomez-Verjan
- Dirección de Investigación, Instituto Nacional de Geriatría (INGER), Ciudad de México 10200, Mexico
| | - Georgina González-Avila
- Laboratorio de Oncología Biomédica, Instituto Nacional de Enfermedades Respiratorias "Ismael Cosío Villegas", México City 14080, Mexico
| | - Edgar Flores-Soto
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Luis M Montaño
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
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Uthman L, Li X, Baartscheer A, Schumacher CA, Baumgart P, Hermanides J, Preckel B, Hollmann MW, Coronel R, Zuurbier CJ, Weber NC. Empagliflozin reduces oxidative stress through inhibition of the novel inflammation/NHE/[Na +] c/ROS-pathway in human endothelial cells. Biomed Pharmacother 2021; 146:112515. [PMID: 34896968 DOI: 10.1016/j.biopha.2021.112515] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/30/2021] [Accepted: 12/06/2021] [Indexed: 02/07/2023] Open
Abstract
Inflammation causing oxidative stress in endothelial cells contributes to heart failure development. Sodium/glucose cotransporter 2 inhibitors (SGLT2i's) were shown to reduce heart failure hospitalization and oxidative stress. However, how inflammation causes oxidative stress in endothelial cells, and how SGLT2i's can reduce this is unknown. Here we hypothesized that 1) TNF-α activates the Na+/H+ exchanger (NHE) and raises cytoplasmatic Na+ ([Na+]c), 2) increased [Na+]c causes reactive oxygen species (ROS) production, and 3) empagliflozin (EMPA) reduces inflammation-induced ROS through NHE inhibition and lowering of [Na+]c in human endothelial cells. Human umbilical vein endothelial cells (HUVECs) and human coronary artery endothelial cells (HCAECs) were incubated with vehicle (V), 10 ng/ml TNF-α, 1 µM EMPA or the NHE inhibitor Cariporide (CARI, 10 µM) and NHE activity, intracellular [Na+]c and ROS were analyzed. TNF-α enhanced NHE activity in HCAECs and HUVECs by 92% (p < 0.01) and 51% (p < 0.05), respectively, and increased [Na+]c from 8.2 ± 1.6 to 11.2 ± 0.1 mM (p < 0.05) in HCAECs. Increasing [Na+]c by ouabain elevated ROS generation in both HCAECs and HUVECs. EMPA inhibited NHE activity in HCAECs and in HUVECs. EMPA concomitantly lowered [Na+]c in both cell types. In both cell types, TNF α-induced ROS was lowered by EMPA or CARI, with no further ROS lowering by EMPA in the presence of CARI, indicating EMPA attenuated ROS through NHE inhibition. In conclusion, inflammation induces oxidative stress in human endothelial cells through NHE activation causing elevations in [Na+]c, a process that is inhibited by EMPA through NHE inhibition.
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Affiliation(s)
- Laween Uthman
- Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Amsterdam UMC, location Academic Medical Centre (AMC), University of Amsterdam, Cardiovascular Sciences, Amsterdam, The Netherlands; Department of Physiology and Cardiology, Radboud Institute for Molecular Life Sciences, Radboud UMC, Nijmegen, The Netherlands
| | - Xiaoling Li
- Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Amsterdam UMC, location Academic Medical Centre (AMC), University of Amsterdam, Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Antonius Baartscheer
- Department of Experimental Cardiology, Amsterdam UMC, location Academic Medical Centre (AMC), University of Amsterdam, Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Cees A Schumacher
- Department of Experimental Cardiology, Amsterdam UMC, location Academic Medical Centre (AMC), University of Amsterdam, Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Patricia Baumgart
- Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Amsterdam UMC, location Academic Medical Centre (AMC), University of Amsterdam, Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Jeroen Hermanides
- Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Amsterdam UMC, location Academic Medical Centre (AMC), University of Amsterdam, Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Benedikt Preckel
- Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Amsterdam UMC, location Academic Medical Centre (AMC), University of Amsterdam, Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Markus W Hollmann
- Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Amsterdam UMC, location Academic Medical Centre (AMC), University of Amsterdam, Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Ruben Coronel
- Department of Experimental Cardiology, Amsterdam UMC, location Academic Medical Centre (AMC), University of Amsterdam, Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Coert J Zuurbier
- Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Amsterdam UMC, location Academic Medical Centre (AMC), University of Amsterdam, Cardiovascular Sciences, Amsterdam, The Netherlands.
| | - Nina C Weber
- Department of Anesthesiology, Laboratory of Experimental Intensive Care and Anesthesiology (L.E.I.C.A.), Amsterdam UMC, location Academic Medical Centre (AMC), University of Amsterdam, Cardiovascular Sciences, Amsterdam, The Netherlands
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Wang X, Xu B, Xiang M, Yang X, Liu Y, Liu X, Shen Y. Advances on fluid shear stress regulating blood-brain barrier. Microvasc Res 2019; 128:103930. [PMID: 31639383 DOI: 10.1016/j.mvr.2019.103930] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 09/18/2019] [Accepted: 09/18/2019] [Indexed: 02/05/2023]
Abstract
The integrity of structure and function of blood-brain barrier (BBB) plays a central role in maintaining the homeostasis of the central nervous system. Patients with severe cerebrovascular stenosis often undergo cerebrovascular bypass surgery. However, the sharply increased fluid shear stress (FSS) after cerebrovascular bypass disrupts the physiological function of brain microvascular endothelial cells (BMECs) at the lesion site, damaging BBB and inducing intracerebral hemorrhage eventually. At present, there are great interests in cerebral vascular flow regulating the structure and function of BBB under physiological and pathological conditions, and most of studies have highlighted the importance of BMECs in BBB. Understanding of how FSS regulating BBB can promote the development of new protective and restorative cerebral vascular interventional therapy.
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Affiliation(s)
- Xiaoli Wang
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu 610041, China
| | - Bowen Xu
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu 610041, China
| | - Mengya Xiang
- West China School of Medicine, Sichuan University, Chengdu 610041, China
| | - Xinyue Yang
- West China School of Medicine, Sichuan University, Chengdu 610041, China
| | - Yi Liu
- Department of Neurosurgery, West China Hospital, Chengdu 610041, China
| | - Xiaoheng Liu
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu 610041, China.
| | - Yang Shen
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu 610041, China.
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Kaisar MA, Sajja RK, Prasad S, Abhyankar VV, Liles T, Cucullo L. New experimental models of the blood-brain barrier for CNS drug discovery. Expert Opin Drug Discov 2016; 12:89-103. [PMID: 27782770 DOI: 10.1080/17460441.2017.1253676] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION The blood-brain barrier (BBB) is a dynamic biological interface which actively controls the passage of substances between the blood and the central nervous system (CNS). From a biological and functional standpoint, the BBB plays a crucial role in maintaining brain homeostasis inasmuch that deterioration of BBB functions are prodromal to many CNS disorders. Conversely, the BBB hinders the delivery of drugs targeting the brain to treat a variety of neurological diseases. Area covered: This article reviews recent technological improvements and innovation in the field of BBB modeling including static and dynamic cell-based platforms, microfluidic systems and the use of stem cells and 3D printing technologies. Additionally, the authors laid out a roadmap for the integration of microfluidics and stem cell biology as a holistic approach for the development of novel in vitro BBB platforms. Expert opinion: Development of effective CNS drugs has been hindered by the lack of reliable strategies to mimic the BBB and cerebrovascular impairments in vitro. Technological advancements in BBB modeling have fostered the development of highly integrative and quasi- physiological in vitro platforms to support the process of drug discovery. These advanced in vitro tools are likely to further current understanding of the cerebrovascular modulatory mechanisms.
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Affiliation(s)
- Mohammad A Kaisar
- a Department of Pharmaceutical Sciences , Texas Tech University Health Sciences Center , Amarillo , TX , USA
| | - Ravi K Sajja
- a Department of Pharmaceutical Sciences , Texas Tech University Health Sciences Center , Amarillo , TX , USA
| | - Shikha Prasad
- a Department of Pharmaceutical Sciences , Texas Tech University Health Sciences Center , Amarillo , TX , USA
| | - Vinay V Abhyankar
- c Biological Microsystems Division at The University of Texas at Arlington Research Institute , Fort Worth , TX , USA
| | - Taylor Liles
- a Department of Pharmaceutical Sciences , Texas Tech University Health Sciences Center , Amarillo , TX , USA
| | - Luca Cucullo
- a Department of Pharmaceutical Sciences , Texas Tech University Health Sciences Center , Amarillo , TX , USA.,b Center for Blood Brain Barrier Research , Texas Tech University Health Sciences Center , Amarillo , TX , USA
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Wang P, Li L, Zhang Z, Kan Q, Gao F, Chen S. Time-dependent activity of Na+/H+ exchanger isoform 1 and homeostasis of intracellular pH in astrocytes exposed to CoCl2 treatment. Mol Med Rep 2016; 13:4443-50. [PMID: 27035646 DOI: 10.3892/mmr.2016.5067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 02/11/2016] [Indexed: 11/06/2022] Open
Abstract
Hypoxia causes injury to the central nervous system during stroke and has significant effects on pH homeostasis. Na+/H+ exchanger isoform 1 (NHE1) is important in the mechanisms of hypoxia and intracellular pH (pHi) homeostasis. As a well-established hypoxia-mimetic agent, CoCl2 stabilizes and increases the expression of hypoxia inducible factor‑1α (HIF-1α), which regulates several genes involved in pH balance, including NHE1. However, it is not fully understood whether NHE1 is activated in astrocytes under CoCl2 treatment. In the current study, pHi and NHE activity were analyzed using the pHi‑sensitive dye BCECF‑AM. Using cariporide (an NHE1‑specific inhibitor) and EIPA (an NHE nonspecific inhibitor), the current study demonstrated that it was NHE1, not the other NHE isoforms, that was important in regulating pHi homeostasis in astrocytes during CoCl2 treatment. Additionally, the present study observed that, during the early period of CoCl2 treatment (the first 2 h), NHE1 activity and pHi dropped immediately, and NHE1 mRNA expression was reduced compared with control levels, whereas expression levels of the NHE1 protein had not yet changed. In the later period of CoCl2 treatment, NHE1 activity and pHi significantly increased compared with the control levels, as did the mRNA and protein expression levels of NHE1. Furthermore, the cell viability and injury of astrocytes was not changed during the initial 8 h of CoCl2 treatment; their deterioration was associated with the higher levels of pHi and NHE1 activity. The current study concluded that NHE1 activity and pHi homeostasis are regulated by CoCl2 treatment in a time-dependent manner in astrocytes, and may be responsible for the changes in cell viability and injury observed under hypoxia-mimetic conditions induced by CoCl2 treatment.
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Affiliation(s)
- Peng Wang
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Ling Li
- Department of Palliative and Hospice Care, The Ninth People's Hospital of Zhengzhou, Zhengzhou, Henan 450053, P.R. China
| | - Zhenxiang Zhang
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Quancheng Kan
- Clinical Pharmacology Base, Department of Infectious Disease, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Feng Gao
- Department of Neuroimmunology, Henan Academy of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Suyan Chen
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
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Sohrabji F. Estrogen-IGF-1 interactions in neuroprotection: ischemic stroke as a case study. Front Neuroendocrinol 2015; 36:1-14. [PMID: 24882635 PMCID: PMC4247812 DOI: 10.1016/j.yfrne.2014.05.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Revised: 05/15/2014] [Accepted: 05/16/2014] [Indexed: 12/25/2022]
Abstract
The steroid hormone 17b-estradiol and the peptide hormone insulin-like growth factor (IGF)-1 independently exert neuroprotective actions in neurologic diseases such as stroke. Only a few studies have directly addressed the interaction between the two hormone systems, however, there is a large literature that indicates potentially greater interactions between the 17b-estradiol and IGF-1 systems. The present review focuses on key issues related to this interaction including IGF-1 and sex differences and common activation of second messenger systems. Using ischemic stroke as a case study, this review also focuses on independent and cooperative actions of estrogen and IGF-1 on neuroprotection, blood brain barrier integrity, angiogenesis, inflammation and post-stroke epilepsy. Finally, the review also focuses on the astrocyte, a key mediator of post stroke repair, as a local source of 17b-estradiol and IGF-1. This review thus highlights areas where significant new research is needed to clarify the interactions between these two neuroprotectants.
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Affiliation(s)
- Farida Sohrabji
- Women's Health in Neuroscience Program, Neuroscience and Experimental Therapeutics, TAMHSC College of Medicine, Bryan, TX 77807, United States.
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Hadjihambi A, Rose CF, Jalan R. Novel insights into ammonia-mediated neurotoxicity pointing to potential new therapeutic strategies. Hepatology 2014; 60:1101-3. [PMID: 24975882 DOI: 10.1002/hep.27282] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/06/2014] [Accepted: 06/25/2014] [Indexed: 01/31/2023]
Affiliation(s)
- Anna Hadjihambi
- Liver failure Group, Institute for Liver and Digestive Health, UCL Medical School, Royal Free Hospital, London, UK
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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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Witt KA, Sandoval KE. Steroids and the blood-brain barrier: therapeutic implications. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 71:361-390. [PMID: 25307223 DOI: 10.1016/bs.apha.2014.06.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Steroids have a wide spectrum of impact, serving as fundamental regulators of nearly every physiological process within the human body. Therapeutic applications of steroids are equally broad, with a diverse range of medications and targets. Within the central nervous system (CNS), steroids influence development, memory, behavior, and disease outcomes. Moreover, steroids are well recognized as to their impact on the vascular endothelium. The blood-brain barrier (BBB) at the level of the brain microvascular endothelium serves as the principle interface between the peripheral circulation and the brain. Steroids have been identified to impact several critical properties of the BBB, including cellular efflux mechanisms, nutrient uptake, and tight junction integrity. Such actions not only influence brain homeostasis but also the delivery of CNS-targeted therapeutics. A greater understanding of the respective steroid-BBB interactions may shed further light on the differential treatment outcomes observed across CNS pathologies. In this chapter, we examine the current therapeutic implications of steroids respective to BBB structure and function, with emphasis on glucocorticoids and estrogens.
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Affiliation(s)
- Ken A Witt
- Pharmaceutical Sciences, School of Pharmacy, Southern Illinois University, Edwardsville, Illinois, USA.
| | - Karin E Sandoval
- Pharmaceutical Sciences, School of Pharmacy, Southern Illinois University, Edwardsville, Illinois, USA
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Sohrabji F, Bake S, Lewis DK. Age-related changes in brain support cells: Implications for stroke severity. Neurochem Int 2013; 63:291-301. [PMID: 23811611 PMCID: PMC3955169 DOI: 10.1016/j.neuint.2013.06.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 05/31/2013] [Accepted: 06/19/2013] [Indexed: 12/14/2022]
Abstract
Stroke is one of the leading causes of adult disability and the fourth leading cause of mortality in the US. Stroke disproportionately occurs among the elderly, where the disease is more likely to be fatal or lead to long-term supportive care. Animal models, where the ischemic insult can be controlled more precisely, also confirm that aged animals sustain more severe strokes as compared to young animals. Furthermore, the neuroprotection usually seen in younger females when compared to young males is not observed in older females. The preclinical literature thus provides a valuable resource for understanding why the aging brain is more susceptible to severe infarction. In this review, we discuss the hypothesis that stroke severity in the aging brain may be associated with reduced functional capacity of critical support cells. Specifically, we focus on astrocytes, that are critical for detoxification of the brain microenvironment and endothelial cells, which play a crucial role in maintaining the blood brain barrier. In view of the sex difference in stroke severity, this review also discusses studies of middle-aged acyclic females as well as the effects of the estrogen on astrocytes and endothelial cells.
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Affiliation(s)
- Farida Sohrabji
- Department of Neuroscience and Experimental Therapeutics, Women's Health in Neuroscience Program, Texas A&M HSC College of Medicine, Bryan, TX 77807, United States.
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11
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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: 57] [Impact Index Per Article: 5.2] [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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Rutkowsky JM, Wallace BK, Wise PM, O'Donnell ME. Effects of estradiol on ischemic factor-induced astrocyte swelling and AQP4 protein abundance. Am J Physiol Cell Physiol 2011; 301:C204-12. [PMID: 21471464 PMCID: PMC3129821 DOI: 10.1152/ajpcell.00399.2010] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 03/30/2011] [Indexed: 11/22/2022]
Abstract
In the early hours of ischemic stroke, cerebral edema forms as Na, Cl, and water are secreted across the blood-brain barrier (BBB) and astrocytes swell. We have shown previously that ischemic factors, including hypoxia, aglycemia, and arginine vasopressin (AVP), stimulate BBB Na-K-Cl cotransporter (NKCC) and Na/H exchanger (NHE) activities and that inhibiting NKCC and/or NHE by intravenous bumetanide and/or HOE-642 reduces edema and infarct in a rat model of ischemic stroke. Estradiol also reduces edema and infarct in this model and abolishes ischemic factor stimulation of BBB NKCC and NHE. There is evidence that NKCC and NHE also participate in ischemia-induced swelling of astrocytes. However, little is known about estradiol effects on astrocyte cell volume. In this study, we evaluated the effects of AVP (100 nM), hypoxia (7.5% O(2)), aglycemia, hypoxia (2%)/aglycemia [oxygen glucose deprivation (OGD)], and estradiol (1-100 nM) on astrocyte cell volume using 3-O-methyl-d-[(3)H]glucose equilibration methods. We found that AVP, hypoxia, aglycemia, and OGD (30 min to 5 h) each significantly increased astrocyte cell volume, and that estradiol (30-180 min) abolished swelling induced by AVP or hypoxia, but not by aglycemia or OGD. Bumetanide and/or HOE-642 also abolished swelling induced by AVP but not aglycemia. Abundance of aquaporin-4, known to participate in ischemia-induced astrocyte swelling, was significantly reduced following 7-day but not 2- or 3-h estradiol exposures. Our findings suggest that hypoxia, aglycemia, and AVP each contribute to ischemia-induced astrocyte swelling, and that the edema-attenuating effects of estradiol include reduction of hypoxia- and AVP-induced astrocyte swelling and also reduction of aquaporin-4 abundance.
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Affiliation(s)
- Jennifer M Rutkowsky
- Department of Physiology and Membrane Biology, University of California, Davis, California 95616, USA
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Uray KS, Shah SK, Radhakrishnan RS, Jimenez F, Walker PA, Stewart RH, Laine GA, Cox CS. Sodium hydrogen exchanger as a mediator of hydrostatic edema-induced intestinal contractile dysfunction. Surgery 2011; 149:114-25. [PMID: 20553904 DOI: 10.1016/j.surg.2010.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 04/13/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND Resuscitation-induced intestinal edema is associated with early and profound mechanical changes in intestinal tissue. We hypothesize that the sodium hydrogen exchanger (NHE), a mechanoresponsive ion channel, is a mediator of edema-induced intestinal contractile dysfunction. METHODS An animal model of hydrostatic intestinal edema was used for all experiments. NHE isoforms 1-3 mRNA and protein were evaluated. Subsequently, the effects of NHE inhibition (with 5-(N-ethyl-N-isopropyl) amiloride [EIPA]) on wet-to-dry ratios, signal transduction and activator of transcription (STAT)-3, intestinal smooth muscle myosin light chain (MLC) phosphorylation, intestinal contractile activity, and intestinal transit were measured. RESULTS NHE1-3 mRNA and protein levels were increased significantly in the small intestinal mucosa with the induction of intestinal edema. The administration of EIPA, an NHE inhibitor, attenuated validated markers of intestinal contractile dysfunction induced by edema as measured by decreased STAT-3 activation, increased MLC phosphorylation, improved intestinal contractile activity, and enhanced intestinal transit. CONCLUSION The mechanoresponsive ion channel NHE may mediate edema-induced intestinal contractile dysfunction, possibly via a STAT-3 related mechanism.
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Affiliation(s)
- Karen S Uray
- Department of Pediatric Surgery, University of Texas Medical School at Houston, Houston, TX 77030, USA
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Shah SK, Fogle LN, Aroom KR, Gill BS, Moore-Olufemi SD, Jimenez F, Uray KS, Walker PA, Stewart RH, Laine GA, Cox CS. Hydrostatic intestinal edema induced signaling pathways: potential role of mechanical forces. Surgery 2010; 147:772-9. [PMID: 20097396 DOI: 10.1016/j.surg.2009.11.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Accepted: 11/24/2009] [Indexed: 01/22/2023]
Abstract
BACKGROUND Hydrostatic intestinal edema initiates a signal transduction cascade that results in smooth muscle contractile dysfunction. Given the rapid and concurrent alterations in the mechanical properties of edematous intestine observed with the development of edema, we hypothesize that mechanical forces may serve as a stimulus for the activation of certain signaling cascades. We sought to examine whether isolated similar magnitude mechanical forces induced the same signal transduction cascades associated with edema. METHODS The distal intestine from adult male Sprague Dawley rats was stretched longitudinally for 2 h to 123% its original length, which correlates with the interstitial stress found with edema. We compared wet-to-dry ratios, myeloperoxidase activity, nuclear signal transduction and activator of transcription (STAT)-3 and nuclear factor (NF)-kappa B DNA binding, STAT-3 phosphorylation, myosin light chain phosphorylation, baseline and maximally stimulated intestinal contractile strength, and inducible nitric oxide synthase (iNOS) and sodium hydrogen exchanger 1-3 messenger RNA (mRNA) in stretched and adjacent control segments of intestine. RESULTS Mechanical stretch did not induce intestinal edema or an increase in myeloperoxidase activity. Nuclear STAT-3 DNA binding, STAT-3 phosphorylation, and nuclear NF-kappa B DNA binding were significantly increased in stretched seromuscular samples. Increased expression of sodium hydrogen exchanger 1 was found but not an increase in iNOS expression. Myosin light chain phosphorylation was significantly decreased in stretched intestine as was baseline and maximally stimulated intestinal contractile strength. CONCLUSION Intestinal stretch, in the absence of edema/inflammatory/ischemic changes, leads to the activation of signaling pathways known to be altered in intestinal edema. Edema may initiate a mechanotransductive cascade that is responsible for the subsequent activation of various signaling cascades known to induce contractile dysfunction.
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Affiliation(s)
- Shinil K Shah
- Department of Pediatric Surgery, University of Texas Medical School at Houston, Houston, TX, USA
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Shah SK, Uray KS, Stewart RH, Laine GA, Cox CS. Resuscitation-induced intestinal edema and related dysfunction: state of the science. J Surg Res 2009; 166:120-30. [PMID: 19959186 DOI: 10.1016/j.jss.2009.09.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 07/24/2009] [Accepted: 09/04/2009] [Indexed: 11/26/2022]
Abstract
High volume resuscitation and damage control surgical methods, while responsible for significantly decreasing morbidity and mortality from traumatic injuries, are associated with pathophysiologic derangements that lead to subsequent end organ edema and dysfunction. Alterations in hydrostatic and oncotic pressures frequently result in intestinal edema and subsequent dysfunction. The purpose of this review is to examine the principles involved in the development of intestinal edema, current and historical models for the study of edema, effects of edema on intestinal function (particularly ileus), molecular mediators governing edema-induced dysfunction, potential role of mechanotransduction , and therapeutic effects of hypertonic saline. We review the current state of the science as it relates to resuscitation induced intestinal edema and resultant dysfunction.
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Affiliation(s)
- Shinil K Shah
- Department of Pediatric Surgery, University of Texas Medical School at Houston, Houston, Texas 77030, USA
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Lam TI, Wise PM, O'Donnell ME. Cerebral microvascular endothelial cell Na/H exchange: evidence for the presence of NHE1 and NHE2 isoforms and regulation by arginine vasopressin. Am J Physiol Cell Physiol 2009; 297:C278-89. [PMID: 19458287 DOI: 10.1152/ajpcell.00093.2009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Blood-brain barrier (BBB) Na transporters are essential for brain water and electrolyte homeostasis. However, they also contribute to edema formation during the early hours of ischemic stroke by increased transport of Na from blood into brain across an intact BBB. We previously showed that a luminal BBB Na-K-Cl cotransporter is stimulated by hypoxia, aglycemia, and AVP and that inhibition of the cotransporter by intravenous bumetanide significantly reduces edema and infarct in the rat middle cerebral artery occlusion (MCAO) model of stroke. More recently, we found evidence that intravenous cariporide (HOE-642), a highly potent Na/H exchange inhibitor, also reduces brain edema after MCAO. The present study was conducted to investigate which Na/H exchange protein isoforms are present in BBB endothelial cells and to evaluate the effects of ischemic factors on BBB Na/H exchange activity. Western blot analysis of bovine cerebral microvascular endothelial cells (CMEC) and immunoelectron microscopy of perfusion-fixed rat brain revealed that Na/H exchanger isoforms 1 and 2 (NHE1 and NHE2) are present in BBB endothelial cells. Using microspectrofluorometry and the pH-sensitive dye BCECF, we found that hypoxia (2% O(2), 30 min), aglycemia (30 min), and AVP (1-200 nM, 5 min) significantly increased CMEC Na/H exchange activity, assessed as Na-dependent, HOE-642-sensitive H(+) flux. We found that AVP stimulation of CMEC Na/H exchange activity is dependent on intracellular Ca concentration and is blocked by V(1), but not V(2), vasopressin receptor antagonists. Our findings support the hypothesis that a BBB Na/H exchanger, possibly NHE1 and/or NHE2, is stimulated during ischemia to participate in cerebral edema formation.
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Affiliation(s)
- Tina I Lam
- Department of Physiology and Membrane Biology, University of California, Davis, CA 95616, USA
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