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Pedersen SF, Counillon L. The SLC9A-C Mammalian Na +/H + Exchanger Family: Molecules, Mechanisms, and Physiology. Physiol Rev 2019; 99:2015-2113. [PMID: 31507243 DOI: 10.1152/physrev.00028.2018] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Na+/H+ exchangers play pivotal roles in the control of cell and tissue pH by mediating the electroneutral exchange of Na+ and H+ across cellular membranes. They belong to an ancient family of highly evolutionarily conserved proteins, and they play essential physiological roles in all phyla. In this review, we focus on the mammalian Na+/H+ exchangers (NHEs), the solute carrier (SLC) 9 family. This family of electroneutral transporters constitutes three branches: SLC9A, -B, and -C. Within these, each isoform exhibits distinct tissue expression profiles, regulation, and physiological roles. Some of these transporters are highly studied, with hundreds of original articles, and some are still only rudimentarily understood. In this review, we present and discuss the pioneering original work as well as the current state-of-the-art research on mammalian NHEs. We aim to provide the reader with a comprehensive view of core knowledge and recent insights into each family member, from gene organization over protein structure and regulation to physiological and pathophysiological roles. Particular attention is given to the integrated physiology of NHEs in the main organ systems. We provide several novel analyses and useful overviews, and we pinpoint main remaining enigmas, which we hope will inspire novel research on these highly versatile proteins.
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Affiliation(s)
- S F Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
| | - L Counillon
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
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Muir W. Effect of Intravenously Administered Crystalloid Solutions on Acid-Base Balance in Domestic Animals. J Vet Intern Med 2017; 31:1371-1381. [PMID: 28833697 PMCID: PMC5598900 DOI: 10.1111/jvim.14803] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/30/2017] [Accepted: 07/13/2017] [Indexed: 12/28/2022] Open
Abstract
Intravenous fluid therapy can alter plasma acid-base balance. The Stewart approach to acid-base balance is uniquely suited to identify and quantify the effects of the cationic and anionic constituents of crystalloid solutions on plasma pH. The plasma strong ion difference (SID) and weak acid concentrations are similar to those of the administered fluid, more so at higher administration rates and with larger volumes. A crystalloid's in vivo effects on plasma pH are described by 3 general rules: SID > [HCO3-] increases plasma pH (alkalosis); SID < [HCO3-] decreases plasma pH (alkalosis); and SID = [HCO3-] yields no change in plasma pH. The in vitro pH of commercially prepared crystalloid solutions has little to no effect on plasma pH because of their low titratable acidity. Appreciation of IV fluid composition and an understanding of basic physicochemical principles provide therapeutically valuable insights about how and why fluid therapy can produce and correct alterations of plasma acid-base equilibrium. The ideal balanced crystalloid should (1) contain species-specific concentrations of key electrolytes (Na+ , Cl- , K+ , Ca++ , Mg++ ), particularly Na+ and Cl- ; (2) maintain or normalize acid-base balance (provide an appropriate SID); and (3) be isosmotic and isotonic (not induce inappropriate fluid shifts) with normal plasma.
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Affiliation(s)
- W. Muir
- College of Veterinary MedicineLincoln Memorial UniversityHarrogateTN
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LASHEEN NN, MOHAMED GF. Possible Mechanisms of Cardiac Contractile Dysfunction and Electrical Changes in Ammonium Chloride Induced Chronic Metabolic Acidosis in Wistar Rats. Physiol Res 2016; 65:927-940. [DOI: 10.33549/physiolres.933171] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Metabolic acidosis could occur due to either endogenous acids accumulation or bicarbonate loss from the gastrointestinal tract or commonly from the kidney. This study aimed to investigate the possible underlying mechanism(s) of chronic acidosis-induced cardiac contractile and electrical changes in rats. Twenty four adult Wistar rats, of both sexes, were randomly divided into control group and chronic metabolic acidosis group, which received orally 0.28 M NH4Cl in the drinking water for 2 weeks. At the end of experimental period, systolic and diastolic blood pressure values were measured. On the day of sacrifice, rats were anesthetized by i.p. pentobarbitone (40 mg/kg b.w.), transthoracic echocardiography and ECG were performed. Blood samples were obtained from abdominal aorta for complete blood count and determination of pH, bicarbonate, chloride, sodium, potassium, troponin I, CK-MB, IL-6, renin and aldosterone levels. Hearts from both groups were studied for cardiac tissue IL-6 and aldosterone in addition to histopathological examination. Compared to control group, chronic metabolic acidosis group showed anemia, significant systolic and diastolic hypotension accompanied by significant reduction of ejection fraction and fraction of shortening, significant bradycardia, prolonged QTc interval and higher widened T wave as well as significantly elevated plasma levels of renin, aldosterone, troponin I, CK-MB and IL-6, and cardiac tissue aldosterone and IL-6. The left ventricular wall of the acidosis group showed degenerated myocytes with fibrosis and apoptosis. Thus, chronic metabolic acidosis induced negative inotropic and chronotropic effects and cardiomyopathy, possibly by elevated aldosterone and IL-6 levels released from the cardiac tissue.
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Affiliation(s)
- N. N. LASHEEN
- Department of Physiology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
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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: 31] [Impact Index Per Article: 3.9] [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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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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Kimmoun A, Novy E, Auchet T, Ducrocq N, Levy B. Hemodynamic consequences of severe lactic acidosis in shock states: from bench to bedside. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2015; 19:175. [PMID: 25887061 PMCID: PMC4391479 DOI: 10.1186/s13054-015-0896-7] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Lactic acidosis is a very common biological issue for shock patients. Experimental data clearly demonstrate that metabolic acidosis, including lactic acidosis, participates in the reduction of cardiac contractility and in the vascular hyporesponsiveness to vasopressors through various mechanisms. However, the contributions of each mechanism responsible for these deleterious effects have not been fully determined and their respective consequences on organ failure are still poorly defined, particularly in humans. Despite some convincing experimental data, no clinical trial has established the level at which pH becomes deleterious for hemodynamics. Consequently, the essential treatment for lactic acidosis in shock patients is to correct the cause. It is unknown, however, whether symptomatic pH correction is beneficial in shock patients. The latest Surviving Sepsis Campaign guidelines recommend against the use of buffer therapy with pH ≥7.15 and issue no recommendation for pH levels <7.15. Furthermore, based on strong experimental and clinical evidence, sodium bicarbonate infusion alone is not recommended for restoring pH. Indeed, bicarbonate induces carbon dioxide generation and hypocalcemia, both cardiovascular depressant factors. This review addresses the principal hemodynamic consequences of shock-associated lactic acidosis. Despite the lack of formal evidence, this review also highlights the various adapted supportive therapy options that could be putatively added to causal treatment in attempting to reverse the hemodynamic consequences of shock-associated lactic acidosis.
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Affiliation(s)
- Antoine Kimmoun
- CHU Nancy, Service de Réanimation Médicale Brabois, Pole Cardiovasculaire et Réanimation Médicale, Hôpital de Brabois, Vandoeuvre-les-Nancy, 54511, France. .,Université de Lorraine, Nancy, 54000, France. .,INSERM U1116, Groupe Choc, Faculté de Médecine, Vandoeuvre-les-Nancy, 54511, France.
| | - Emmanuel Novy
- CHU Nancy, Service de Réanimation Médicale Brabois, Pole Cardiovasculaire et Réanimation Médicale, Hôpital de Brabois, Vandoeuvre-les-Nancy, 54511, France. .,Université de Lorraine, Nancy, 54000, France.
| | - Thomas Auchet
- CHU Nancy, Service de Réanimation Médicale Brabois, Pole Cardiovasculaire et Réanimation Médicale, Hôpital de Brabois, Vandoeuvre-les-Nancy, 54511, France.
| | - Nicolas Ducrocq
- CHU Nancy, Service de Réanimation Médicale Brabois, Pole Cardiovasculaire et Réanimation Médicale, Hôpital de Brabois, Vandoeuvre-les-Nancy, 54511, France.
| | - Bruno Levy
- CHU Nancy, Service de Réanimation Médicale Brabois, Pole Cardiovasculaire et Réanimation Médicale, Hôpital de Brabois, Vandoeuvre-les-Nancy, 54511, France. .,Université de Lorraine, Nancy, 54000, France. .,INSERM U1116, Groupe Choc, Faculté de Médecine, Vandoeuvre-les-Nancy, 54511, France.
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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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Metabolic acidosis treatment as part of a strategy to curb inflammation. Int J Inflam 2013; 2013:601424. [PMID: 23841017 PMCID: PMC3690240 DOI: 10.1155/2013/601424] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 05/22/2013] [Accepted: 05/22/2013] [Indexed: 11/17/2022] Open
Abstract
Abnormalities in systemic acid-base balance may induce significant changes in the immune response, and they may play a significant role in the development or maintenance of immune dysfunction. Different forms of acidosis (metabolic and respiratory) and even different types of metabolic acidosis (hyperchloremic and lactic) may produce different effects on immune function. If alkalization has, or not, some effect on inflammation control is still a matter of speculation. Studies concerning these subjects are limited justifying this paper.
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