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Nikolovska K, Seidler UE, Stock C. The Role of Plasma Membrane Sodium/Hydrogen Exchangers in Gastrointestinal Functions: Proliferation and Differentiation, Fluid/Electrolyte Transport and Barrier Integrity. Front Physiol 2022; 13:899286. [PMID: 35665228 PMCID: PMC9159811 DOI: 10.3389/fphys.2022.899286] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 04/19/2022] [Indexed: 12/11/2022] Open
Abstract
The five plasma membrane Na+/H+ exchanger (NHE) isoforms in the gastrointestinal tract are characterized by distinct cellular localization, tissue distribution, inhibitor sensitivities, and physiological regulation. NHE1 (Slc9a1) is ubiquitously expressed along the gastrointestinal tract in the basolateral membrane of enterocytes, but so far, an exclusive role for NHE1 in enterocyte physiology has remained elusive. NHE2 (Slc9a2) and NHE8 (Slc9a8) are apically expressed isoforms with ubiquitous distribution along the colonic crypt axis. They are involved in pHi regulation of intestinal epithelial cells. Combined use of a knockout mouse model, intestinal organoid technology, and specific inhibitors revealed previously unrecognized actions of NHE2 and NHE8 in enterocyte proliferation and differentiation. NHE3 (Slc9a3), expressed in the apical membrane of differentiated intestinal epithelial cells, functions as the predominant nutrient-independent Na+ absorptive mechanism in the gut. The new selective NHE3 inhibitor (Tenapanor) allowed discovery of novel pathophysiological and drug-targetable NHE3 functions in cystic-fibrosis associated intestinal obstructions. NHE4, expressed in the basolateral membrane of parietal cells, is essential for parietal cell integrity and acid secretory function, through its role in cell volume regulation. This review focuses on the expression, regulation and activity of the five plasma membrane Na+/H+ exchangers in the gastrointestinal tract, emphasizing their role in maintaining intestinal homeostasis, or their impact on disease pathogenesis. We point to major open questions in identifying NHE interacting partners in central cellular pathways and processes and the necessity of determining their physiological role in a system where their endogenous expression/activity is maintained, such as organoids derived from different parts of the gastrointestinal tract.
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Hu Y, Lou J, Jin Z, Yang X, Shan W, Du Q, Liao Q, Xu J, Xie R. Advances in research on the regulatory mechanism of NHE1 in tumors. Oncol Lett 2021; 21:273. [PMID: 33717270 PMCID: PMC7885159 DOI: 10.3892/ol.2021.12534] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 12/17/2020] [Indexed: 12/11/2022] Open
Abstract
Tumors pose a major threat to human health and present with difficulties that modern medicine has yet to overcome. It has been demonstrated that the acid-base balance of the tumor microenvironment is closely associated with the dynamic balance in the human body and that it regulates several processes, such as cell proliferation and differentiation, intracellular enzyme activity, and cytoskeletal assembly and depolymerization. It has been well established that the regulation of intra- and extracellular pH depends on a series of functional ion transporters and hydrogen ion channels, such as the Na+/H+ exchanger (NHE) protein and thee Cl/HCO3- exchange protein, among which the NHE1 member of the NHE family has been attracting increasing attention in recent years, particularly in studies on the correlation between pH regulation and tumors. NHE1 is a housekeeping gene encoding a protein that is widely expressed on the surface of all plasma membranes. Due to its functional domain, which determines the pHi at its N-terminus and C-terminus, NHE1 is involved in the regulation of the cellular pH microenvironment. It has been reported in the literature that NHE1 can regulate cell volume, participate in the transmembrane transport of intracellular and extracellular ions, affect cell proliferation and apoptosis, and regulate cell behavior and cell cycle progression; however, research on the role of NHE1 in tumorigenesis and tumor development in various systems is at its early stages. The aim of the present study was to review the current research on the correlation between the NHE family proteins and various systemic tumors, in order to indicate a new direction for antitumor drug development with the pH microenvironment as the target.
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Affiliation(s)
- Yanxia Hu
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Jun Lou
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Zhe Jin
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Xiaoxu Yang
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Weixi Shan
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Qian Du
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Qiushi Liao
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Jingyu Xu
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Rui Xie
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
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Deng X, Ji Z, Xu B, Guo L, Xu L, Qin T, Feng L, Ma Z, Fu Q, Qu R, Quo Q, Ma S. Suppressing the Na +/H + exchanger 1: a new sight to treat depression. Cell Death Dis 2019; 10:370. [PMID: 31068571 PMCID: PMC6506522 DOI: 10.1038/s41419-019-1602-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 03/25/2019] [Accepted: 04/17/2019] [Indexed: 11/09/2022]
Abstract
Na+/H+ exchanger 1 (NHE1), an important regulator of intracellular pH (pHi) and extracellular pH (pHe), plays a crucial role in various physiological and pathological processes. However, the role of NHE1 in depression has not yet been reported. This study was designed to investigate the role of NHE1 in the animal model of depression and explore the underlying mechanisms. Our results showed that inhibition of rho-associated kinase 2 (ROCK2) by fasudil (Fas) or baicalin (BA) significantly alleviated chronic unpredictable mild stress (CUMS) paradigm-induced depression-related behaviours in mice, as shown by decreased sucrose consumption in sucrose preference test (SPT), reduced locomotor activity in the open field test (OFT), and increased immobility time in the tail suspension test (TST) and forced swimming test (FST). Furthermore, ROCK2 inhibition inhibited the activation of NHE1, calpain1, and reduced neuronal apoptosis in the CUMS animal model of depression. Next, we used the lipopolysaccharide (LPS)-challenged animal model of depression to induce NHE1 activation. Our results revealed that mice subjected to 1 μl LPS (10 mg/ml) injection intracerebroventricularly (i.c.v.) showed depressive-like behaviours and NHE1 activation. Amiloride (Ami), an NHE1 inhibitor, significantly reversed the decrease in sucrose consumption and reduction in immobility time in the TST and FST induced by LPS challenge. Furthermore, Ami decreased the expression of ROCK2, NHE1, calpain1, and caspase-3 and increased the Bcl-1/Bax ratio in the hippocampus of LPS-challenged mice. Ami treatment also led to antidepressive effects in the CUMS-induced animal model of depression. Thus ROCK2 inhibition could be proposed as a neuroprotective strategy against neuronal apoptosis, and NHE1 might be a potential therapeutic target in depression.
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Affiliation(s)
- Xueyang Deng
- Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, 210009, Nanjing, China.,State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 210009, Nanjing, China
| | - Zhouye Ji
- Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, 210009, Nanjing, China
| | - Bingru Xu
- Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, 210009, Nanjing, China
| | - Liting Guo
- Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, 210009, Nanjing, China
| | | | - Tingting Qin
- Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, 210009, Nanjing, China
| | - Liang Feng
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, 211198, Nanjing, Jiangsu, China
| | - Zhanqiang Ma
- Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, 210009, Nanjing, China
| | - Qiang Fu
- Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, 210009, Nanjing, China
| | - Rong Qu
- Department of Pharmacology of Traditional Chinese Medical Formulae, Nanjing University of Traditional Chinese Medicine, 210029, Nanjing, China
| | - Qinglong Quo
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 210009, Nanjing, China.
| | - Shiping Ma
- Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, 210009, Nanjing, China. .,Qinba Traditional Chinese Medicine Resources Research and Development Center, AnKang University, 725000, AnKang, PR China.
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Denk S, Neher MD, Messerer DAC, Wiegner R, Nilsson B, Rittirsch D, Nilsson-Ekdahl K, Weckbach S, Ignatius A, Kalbitz M, Gebhard F, Weiss ME, Vogt J, Radermacher P, Köhl J, Lambris JD, Huber-Lang MS. Complement C5a Functions as a Master Switch for the pH Balance in Neutrophils Exerting Fundamental Immunometabolic Effects. THE JOURNAL OF IMMUNOLOGY 2017; 198:4846-4854. [PMID: 28490576 DOI: 10.4049/jimmunol.1700393] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 04/16/2017] [Indexed: 01/08/2023]
Abstract
During sepsis, excessive activation of the complement system with generation of the anaphylatoxin C5a results in profound disturbances in crucial neutrophil functions. Moreover, because neutrophil activity is highly dependent on intracellular pH (pHi), we propose a direct mechanistic link between complement activation and neutrophil pHi In this article, we demonstrate that in vitro exposure of human neutrophils to C5a significantly increased pHi by selective activation of the sodium/hydrogen exchanger. Upstream signaling of C5a-mediated intracellular alkalinization was dependent on C5aR1, intracellular calcium, protein kinase C, and calmodulin, and downstream signaling regulated the release of antibacterial myeloperoxidase and lactoferrin. Notably, the pH shift caused by C5a increased the glucose uptake and activated glycolytic flux in neutrophils, resulting in a significant release of lactate. Furthermore, C5a induced acidification of the extracellular micromilieu. In experimental murine sepsis, pHi of blood neutrophils was analogously alkalinized, which could be normalized by C5aR1 inhibition. In the clinical setting of sepsis, neutrophils from patients with septic shock likewise exhibited a significantly increased pHi These data suggest a novel role for the anaphylatoxin C5a as a master switch of the delicate pHi balance in neutrophils resulting in profound inflammatory and metabolic changes that contribute to hyperlactatemia during sepsis.
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Affiliation(s)
- Stephanie Denk
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Miriam D Neher
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - David A C Messerer
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Rebecca Wiegner
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital Ulm, 89081 Ulm, Germany
| | - Bo Nilsson
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, 751 85 Uppsala, Sweden
| | - Daniel Rittirsch
- Department of Plastic Surgery and Hand Surgery, University Hospital Zurich, 8091 Zurich, Switzerland
| | | | - Sebastian Weckbach
- Department of Orthopedic Surgery, Ulm University, University and Rehabilitation Clinics Ulm, 89081 Ulm, Germany
| | - Anita Ignatius
- Institute of Orthopedic Research and Biomechanics, Ulm University, 89081 Ulm, Germany
| | - Miriam Kalbitz
- Department of Traumatology, Hand, Plastic, and Reconstructive Surgery, University Hospital Ulm, 89081 Ulm, Germany
| | - Florian Gebhard
- Department of Traumatology, Hand, Plastic, and Reconstructive Surgery, University Hospital Ulm, 89081 Ulm, Germany
| | - Manfred E Weiss
- Department of Anesthesiology, University Hospital Ulm, 89081 Ulm, Germany
| | - Josef Vogt
- Institute of Anesthesiological Pathophysiology and Process Engineering, Ulm University, 89081 Ulm, Germany
| | - Peter Radermacher
- Institute of Anesthesiological Pathophysiology and Process Engineering, Ulm University, 89081 Ulm, Germany
| | - Jörg Köhl
- Institute for Systemic Inflammation Research, University of Lübeck, 23538 Lübeck, Germany.,Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229; and
| | - John D Lambris
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Markus S Huber-Lang
- Institute of Clinical and Experimental Trauma-Immunology, University Hospital Ulm, 89081 Ulm, Germany;
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Magalhães D, Cabral JM, Soares-da-Silva P, Magro F. Role of epithelial ion transports in inflammatory bowel disease. Am J Physiol Gastrointest Liver Physiol 2016; 310:G460-76. [PMID: 26744474 DOI: 10.1152/ajpgi.00369.2015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 01/02/2016] [Indexed: 02/06/2023]
Abstract
Inflammatory bowel disease (IBD) is a chronic inflammatory disorder with a complex pathogenesis. Diarrhea is a highly prevalent and often debilitating symptom of IBD patients that results, at least in part, from an intestinal hydroelectrolytic imbalance. Evidence suggests that reduced electrolyte absorption is more relevant than increased secretion to this disequilibrium. This systematic review analyses and integrates the current evidence on the roles of epithelial Na(+)-K(+)-ATPase (NKA), Na(+)/H(+) exchangers (NHEs), epithelial Na(+) channels (ENaC), and K(+) channels (KC) in IBD-associated diarrhea. NKA is the key driving force of the transepithelial ionic transport and its activity is decreased in IBD. In addition, the downregulation of apical NHE and ENaC and the upregulation of apical large-conductance KC all contribute to the IBD-associated diarrhea by lowering sodium absorption and/or increasing potassium secretion.
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Affiliation(s)
- Diogo Magalhães
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - José Miguel Cabral
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - Patrício Soares-da-Silva
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
| | - Fernando Magro
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal; and MedInUP-Center for Drug Discovery and Innovative Medicines, University of Porto, Porto, Portugal
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Murugesan P, Jung B, Lee D, Khang G, Doods H, Wu D. Kinin B1 Receptor Inhibition With BI113823 Reduces Inflammatory Response, Mitigates Organ Injury, and Improves Survival Among Rats With Severe Sepsis. J Infect Dis 2015; 213:532-40. [PMID: 26310310 DOI: 10.1093/infdis/jiv426] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/11/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND This study examined the therapeutic effects of an orally active nonpeptide kinin B1 receptor antagonist, BI113823, in a clinically relevant experimental model of polymicrobial sepsis in rats. METHODS Sepsis was induced by cecal ligation and puncture (CLP). Animals received treatment with either vehicle or BI113823. The experiment was terminated in the first set of animals 15 hours after CLP. Seven-day survival following CLP was determined in the second set of animals. RESULTS Compared with vehicle treatment, administration of BI113823 reduced neutrophil and macrophage infiltration, reduced cytokine production, attenuated intestinal mucosal hyperpermeability, prevented hemodynamic derangement, and improved cardiac output. Furthermore, administration of BI113823 reduced inducible nitric oxide synthase expression and the injury score in the lung and attenuated nuclear factor ĸB activation and apoptosis in the liver. Treatment with BI113823 also reduced plasma levels of cardiac troponin, aspartate aminotransferase, alanine aminotransferase, urea, and lactate, as well as proteinuria. Finally, administration of BI113823 improved the 7-day survival rate following CLP in rats. CONCLUSIONS Administration of BI113823 reduced systemic and tissue inflammatory responses, prevented hemodynamic derangement, attenuated multiorgan injury, and improved overall survival.
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Affiliation(s)
- Priya Murugesan
- Department of BIN Fusion Technology, World Class University Program, Chonbuk National University, Jeonju, Korea
| | - Birgit Jung
- Respiratory Diseases Research, Boehringer Ingelheim Pharma, Biberach, Germany
| | - Dongwon Lee
- Department of BIN Fusion Technology, World Class University Program, Chonbuk National University, Jeonju, Korea
| | - Gilson Khang
- Department of BIN Fusion Technology, World Class University Program, Chonbuk National University, Jeonju, Korea
| | - Henri Doods
- Respiratory Diseases Research, Boehringer Ingelheim Pharma, Biberach, Germany
| | - Dongmei Wu
- Department of BIN Fusion Technology, World Class University Program, Chonbuk National University, Jeonju, Korea Department of Research, Mount Sinai Medical Center, Miami Beach, Florida
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Interaction of sodium bicarbonate and Na+/H+ exchanger inhibition in the treatment of acute metabolic acidosis in pigs. Crit Care Med 2015; 43:e160-9. [PMID: 25785519 DOI: 10.1097/ccm.0000000000000962] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Administration of NaHCO3 does not improve cellular function or reduce the mortality of acute lactic acidosis. This might be related to aggravation of intracellular acidosis, but it could also be due to activation of Na+/H+ exchanger with a deleterious increment in intracellular calcium ([Ca2+]i). This study examined the impact of coadministration of NaHCO3 and a selective inhibitor of Na+/H+ exchanger, sabiporide on cardiovascular function, changes in proinflammatory cytokines, and organ function in a model of acute lactic acidosis produced by hemorrhagic hypotension followed by infusion of lactic acid. DESIGN Experimental, prospective study. SETTING Medical Center research laboratory. SUBJECTS Male Yorkshire pigs. INTERVENTIONS Anesthetized pigs were subjected to hypovolemia for 30 minutes and followed by DL-lactic acid infusion, and then either saline or sodium bicarbonate was infused. MEASUREMENTS AND MAIN RESULTS Hypovolemia followed by a DL-lactic acid infusion resulted in severe acidemia with a blood pH~6.8. Administration of NaHCO3 did not improve cardiovascular performance or decrease the levels of proinflammatory responses, whereas administration of sabiporide prior to acid or NaHCO3 infusion improved cardiopulmonary performance and blood oxygenation, reduced nuclear factor-κB activation, neutrophil accumulation, and proinflammatory cytokine production, and attenuated organ injury. Exposure of rat cardiac myocytes to a pH of 7.2 led to a marked increase of [Ca2+]i, and release of lactate dehydrogenase from cells which were further augmented after increase in external pH by addition of NaHCO3. Both the increase in [Ca2+]i and release of lactate dehydrogenase were attenuated in the presence of sabiporide. CONCLUSIONS Coadministration of Na/H exchanger inhibitor with sodium bicarbonate improves cardiovascular performances, reduces proinflammatory responses, and attenuates organ injury. This improvement in these variables appears to be related to prevention of a rise in intracellular calcium occurring after both exposures to acid and bicarbonate.
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Lin X, Kraut JA, Wu D. Coadministration of a Na+-H+ exchange inhibitor and sodium bicarbonate for the treatment of asphyxia-induced cardiac arrest in piglets. Pediatr Res 2014; 76:118-26. [PMID: 24796369 DOI: 10.1038/pr.2014.65] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 01/27/2014] [Indexed: 11/09/2022]
Abstract
BACKGROUND The present study tested the hypothesis that addition of an inhibitor of Na(+)/H(+) exchanger (NHE1) to sodium bicarbonate might improve the response to base therapy from prolonged asphyxial cardiac arrest in piglets. METHODS Asphyxial cardiac arrest was induced by endotracheal tube clamping. Animals were randomly assigned to four study groups: (i) vehicle control, (ii) administration of sabiporide (NHE1 inhibitor), (iii) administration of sodium bicarbonate, and (iv) administration of sabiporide and sodium bicarbonate. RESULTS Administration of sodium bicarbonate alone did not affect survival, hemodynamic measures, and regional blood flow to critical tissues such as brain, heart, kidney, liver, and spleen. In contrast, sabiporide given alone or combined with sodium bicarbonate improved these. Furthermore, treatment with sabiporide reduced accumulation of neutrophils, reduced cytokine production in the lung, and reduced plasma levels of cardiac troponin-I, alanine aminotransferase, aspartate aminotransferase, and urea. In addition, the combined use of sabiporide and sodium bicarbonate had more profound reduction in interleukin (IL)-6 and IL-10, compared to sabiporide alone. CONCLUSION These results suggest that addition of sabiporide to the administration of sodium bicarbonate might improve hemodynamic response and dampen the inflammatory cascade noted with cardiac arrest, and therefore being an attractive option in the treatment of cardiac arrest.
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Affiliation(s)
- Xinchun Lin
- Department of Research, Mount Sinai Medical Center, Miami Beach, Florida
| | - Jeffrey A Kraut
- 1] Medical and Research Services and Division of Nephrology, Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, California [2] David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Dongmei Wu
- 1] Department of Research, Mount Sinai Medical Center, Miami Beach, Florida [2] Department of Biotechnology, Information Science, and Nanotechnology (BIN) Fusion Technology, Chonbuk National University, Jeonju, Korea
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Abstract
BACKGROUND Metabolic acidosis is associated with impaired cellular function. This has been attributed to the accompanying reduction in intracellular and interstitial pH of the myocardium. Recent studies suggest that activation of the cellular Na(+)-H(+) exchanger NHE1 might contribute to myocardial dysfunction. This review examines the experimental evidence which supports the role of NHE1 in the genesis of acidosis-induced cellular dysfunction, the benefits of its inhibition, and the type of acidosis that might benefit from therapy. SUMMARY Information was obtained by searching MEDLINE for articles published between 1969 and 2013 using the terms: NHE1, metabolic acidosis, lactic acidosis, ischemia-reperfusion, shock, resuscitation, high anion gap acidosis, and non-gap acidosis. Each article was also reviewed for additional suitable references. Nineteen manuscripts published between 2002 and 2013 assessed the impact of inhibition of NHE1 on cellular function. They revealed that NHE1 is activated with metabolic acidosis associated with hypoxia, hypoperfusion, hemorrhagic shock, and sepsis. This was associated with a rise in cellular sodium and calcium and cardiac dysfunction including reduced contractility and a predisposition to cardiac arrhythmias. Inhibition of NHE1 with specific inhibitors improved cardiac function, reduced blood and tissue levels of proinflammatory cytokines, and decreased mortality. Key Message: These results suggest that use of inhibitors of NHE1 might be worthwhile in the treatment of some types of acute metabolic acidosis, specifically the lactic acidosis associated with hypoxia, hemorrhagic shock, and cardiac arrest. Its potential role in the treatment of other forms of acute metabolic acidosis remains to be determined.
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Affiliation(s)
- Dongmei Wu
- Department of Research, Mount Sinai Medical Center, Miami, Fla., USA
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Lin X, Lee D, Wu D. Sabiporide improves cardiovascular function and attenuates organ injury from severe sepsis. J Surg Res 2014; 188:231-7. [DOI: 10.1016/j.jss.2013.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 12/02/2013] [Accepted: 12/06/2013] [Indexed: 10/25/2022]
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Abstract
The majority of injury combinations in multiply injured patients entail the chest, abdomen, and extremities. Numerous pig models focus on the investigation of posttraumatic pathophysiology, organ performance monitoring and on potential treatment options. Depending on the experimental question, previous authors have included isolated insults (controlled or uncontrolled hemorrhage, chest trauma) or a combination of these injuries (hemorrhage with abdominal trauma, chest trauma, traumatic brain injury, and/or long-bone fractures). Combined trauma models in pigs can provide a high level of clinical relevance, when they are properly designed and mimicking the clinical situation. Most of these models focus on the first hours after trauma, to assess the acute sequel of traumatic hemorrhage. However, hemorrhagic shock and the associated mass transfusion are also major causes for organ failure and mortality in the later clinical course. Thus, most models lack information on the pathomechanisms during the late posttraumatic phase. Studying new therapies only during the early phase is also not reflective of the clinical situation. Therefore, a longer observation period is required to study the effects of therapeutic approaches during intensive care treatment when using animal models. These long-term studies of combined trauma models will allow the development of valuable therapeutic approaches relevant for the later posttraumatic course. This review summarizes the existing porcine models and outlines the need for long-term models to provide real effective novel therapeutics for multiply injured patients to improve organ function and clinical outcome.
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Yang X, Bai H, Cai W, Liu J, Wang Y, Xu Y, Li J, Zhou Q, Han J, Zhu X, Dong M, Hu D. Inhibition of Na+/H+ exchanger 1 by cariporide alleviates burn-induced multiple organ injury. J Surg Res 2013; 185:797-804. [DOI: 10.1016/j.jss.2013.06.049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 06/16/2013] [Accepted: 06/20/2013] [Indexed: 12/11/2022]
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Yang X, Chen J, Bai H, Tao K, Zhou Q, Hou H, Hu D. Inhibition of Na+/H+ exchanger 1 by cariporide reduces burn-induced intestinal barrier breakdown. Burns 2013; 39:1557-64. [DOI: 10.1016/j.burns.2013.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Revised: 04/07/2013] [Accepted: 04/10/2013] [Indexed: 12/29/2022]
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Wu D, Kraut JA, Abraham WM. Sabiporide improves cardiovascular function, decreases the inflammatory response and reduces mortality in acute metabolic acidosis in pigs. PLoS One 2013; 8:e53932. [PMID: 23326542 PMCID: PMC3542271 DOI: 10.1371/journal.pone.0053932] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 12/07/2012] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Acute metabolic acidosis impairs cardiovascular function and increases the mortality of critically ill patients. However, the precise mechanism(s) underlying these effects remain unclear. We hypothesized that targeting pH-regulatory protein, Na(+)/H(+) exchanger (NHE1) could be a novel approach for the treatment of acute metabolic acidosis. The aim of the present study was to examine the impact of a novel NHE1 inhibitor, sabiporide, on cardiovascular function, blood oxygen transportation, and inflammatory response in an experimental model of metabolic acidosis produced by hemorrhage-induced hypovolemia followed by an infusion of lactic acid. METHODS AND RESULTS Anesthetized pigs were subjected to hypovolemia for 30 minutes. The animals then received a bolus infusion of sabiporide (3 mg/kg) or vehicle, followed by an infusion of lactic acid for 2 hours. The animals were continuously monitored for additional 3 hours. Hypovolemia followed by a lactic acid infusion resulted in a severe metabolic acidosis with blood pH falling to 6.8. In association with production of the acidemia, there was an excessive increase in pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR). Treatment with sabiporide significantly attenuated the increase in PAP by 38% and PVR by 67%, as well as significantly improved cardiac output by 51%. Sabiporide treatment also improved mixed venous blood oxygen saturation (55% in sabiporide group vs. 28% in control group), and improved systemic blood oxygen delivery by 36%. In addition, sabiporide treatment reduced plasma levels of TNF-α (by 33%), IL-6 (by 63%), troponin-I (by 54%), ALT (by 34%), AST (by 35%), and urea (by 40%). CONCLUSION These findings support the possible beneficial effects of sabiporide in the treatment of acute metabolic acidosis and could have implications for the treatment of metabolic acidosis in man.
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Affiliation(s)
- Dongmei Wu
- Department of Research, Division of Neonatology, Mount Sinai Medical Center, Miami Beach, Florida, United States of America.
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Effects of a novel bradykinin B1 receptor antagonist and angiotensin II receptor blockade on experimental myocardial infarction in rats. PLoS One 2012; 7:e51151. [PMID: 23236443 PMCID: PMC3517424 DOI: 10.1371/journal.pone.0051151] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 10/29/2012] [Indexed: 01/06/2023] Open
Abstract
Background The aim of the present study was to evaluate the cardiovascular effects of the novel bradykinin B1 receptor antagonist BI-113823 following myocardial infarction (MI) and to determine whether B1 receptor blockade alters the cardiovascular effects of an angiotensin II type 1 (AT1) receptor antagonist after MI in rats. Methodology/Principal Findings Sprague Dawley rats were subjected to permanent occlusion of the left descending coronary artery. Cardiovascular function was determined at 7 days post MI. Treatment with either B1 receptor antagonist (BI-113823) or AT1 receptor antagonist (irbesartan) alone or in combination improved post-MI cardiac function as evidenced by attenuation of elevated left ventricular end diastolic pressure (LVEDP); greater first derivative of left ventricular pressure (± dp/dt max), left ventricle ejection fraction, fractional shorting, and better wall motion; as we as reductions in post-MI up-regulation of matrix metalloproteinases 2 (MMP-2) and collagen III. In addition, the cardiac up-regulation of B1 receptor and AT1 receptor mRNA were markedly reduced in animals treated with BI 113823, although bradykinin B2 receptor and angiotensin 1 converting enzyme (ACE1) mRNA expression were not significantly affected by B1 receptor blockade. Conclusions/Significance The present study demonstrates that treatment with the novel B1 receptor antagonist, BI-113823 improves post-MI cardiac function and does not influence the cardiovascular effects of AT1 receptor antagonist following MI.
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