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Zanza C, Saglietti F, Tesauro M, Longhitano Y, Savioli G, Balzanelli MG, Romenskaya T, Cofone L, Pindinello I, Racca G, Racca F. Cardiogenic Pulmonary Edema in Emergency Medicine. Adv Respir Med 2023; 91:445-463. [PMID: 37887077 PMCID: PMC10604083 DOI: 10.3390/arm91050034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 10/06/2023] [Accepted: 10/10/2023] [Indexed: 10/28/2023]
Abstract
Cardiogenic pulmonary edema (CPE) is characterized by the development of acute respiratory failure associated with the accumulation of fluid in the lung's alveolar spaces due to an elevated cardiac filling pressure. All cardiac diseases, characterized by an increasing pressure in the left side of the heart, can cause CPE. High capillary pressure for an extended period can also cause barrier disruption, which implies increased permeability and fluid transfer into the alveoli, leading to edema and atelectasis. The breakdown of the alveolar-epithelial barrier is a consequence of multiple factors that include dysregulated inflammation, intense leukocyte infiltration, activation of procoagulant processes, cell death, and mechanical stretch. Reactive oxygen and nitrogen species (RONS) can modify or damage ion channels, such as epithelial sodium channels, which alters fluid balance. Some studies claim that these patients may have higher levels of surfactant protein B in the bloodstream. The correct approach to patients with CPE should include a detailed medical history and a physical examination to evaluate signs and symptoms of CPE as well as potential causes. Second-level diagnostic tests, such as pulmonary ultrasound, natriuretic peptide level, chest radiograph, and echocardiogram, should occur in the meantime. The identification of the specific CPE phenotype is essential to set the most appropriate therapy for these patients. Non-invasive ventilation (NIV) should be considered early in the treatment of this disease. Diuretics and vasodilators are used for pulmonary congestion. Hypoperfusion requires treatment with inotropes and occasionally vasopressors. Patients with persistent symptoms and diuretic resistance might benefit from additional approaches (i.e., beta-agonists and pentoxifylline). This paper reviews the pathophysiology, clinical presentation, and management of CPE.
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Affiliation(s)
- Christian Zanza
- Post Graduate School of Geriatric Medicine, University of Rome “Tor Vergata”, 00133 Rome, Italy
- Italian Society of Prehospital Emergency Medicine (SIS 118), 74121 Taranto, Italy
| | - Francesco Saglietti
- Department of Emergency and Critical Care, Santa Croce and Carle Hospital, 12100 Cuneo, Italy
| | - Manfredi Tesauro
- Post Graduate School of Geriatric Medicine, University of Rome “Tor Vergata”, 00133 Rome, Italy
- Department of Systems Medicine, University of Rome “Tor Vergata”, 00133 Rome, Italy
| | - Yaroslava Longhitano
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Department of Emergency Medicine, Humanitas University Hospital, 20089 Rozzano, Italy
| | - Gabriele Savioli
- Emergency Department, IRCCS Fondazione Policlinico San Matteo, 27100 Pavia, Italy;
| | | | - Tatsiana Romenskaya
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
| | - Luigi Cofone
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (I.P.)
| | - Ivano Pindinello
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy; (L.C.); (I.P.)
| | - Giulia Racca
- Division of Anesthesia and Critical Care Medicine, AO Ordine Mauriziano, 10128 Turin, Italy; (G.R.)
| | - Fabrizio Racca
- Division of Anesthesia and Critical Care Medicine, AO Ordine Mauriziano, 10128 Turin, Italy; (G.R.)
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Baloglu E, Velineni K, Ermis-Kaya E, Mairbäurl H. Hypoxia Aggravates Inhibition of Alveolar Epithelial Na-Transport by Lipopolysaccharide-Stimulation of Alveolar Macrophages. Int J Mol Sci 2022; 23:ijms23158315. [PMID: 35955448 PMCID: PMC9368968 DOI: 10.3390/ijms23158315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/22/2022] [Accepted: 07/25/2022] [Indexed: 11/16/2022] Open
Abstract
Inflammation and hypoxia impair alveolar barrier tightness, inhibit Na- and fluid reabsorption, and cause edema. We tested whether stimulated alveolar macrophages affect alveolar Na-transport and whether hypoxia aggravates the effects of inflammation, and tested for involved signaling pathways. Primary rat alveolar type II cells (rA2) were co-cultured with rat alveolar macrophages (NR8383) or treated with NR8383-conditioned media after stimulation with lipopolysaccharide (LPS; 1 µg/mL) and exposed to normoxia and hypoxia (1.5% O2). LPS caused a fast, transient increase in TNFα and IL-6 mRNA in macrophages and a sustained increase in inducible nitric oxide synthase (NOS2) mRNA in macrophages and in rA2 cells resulting in elevated nitrite levels and secretion of TNF-α and IL-6 into culture media. In normoxia, 24 h of LPS treated NR8383 decreased the transepithelial electrical resistance (TEER) of co-cultures, of amiloride-sensitive short circuit current (ISCΔamil); whereas Na/K-ATPase activity was not affected. Inhibition was also seen with conditioned media from LPS-stimulated NR8383 on rA2, but was less pronounced after dialysis to remove small molecules and nitrite. The effect of LPS-stimulated macrophages on TEER and Na-transport was fully prevented by the iNOS-inhibitor L-NMMA applied to co-cultures and to rA2 mono-cultures. Hypoxia in combination with LPS-stimulated NR8383 totally abolished TEER and ISCΔamil. These results indicate that the LPS-stimulation of alveolar macrophages impairs alveolar epithelial Na-transport by NO-dependent mechanisms, where part of the NO is produced by rA2 induced by signals from LPS stimulated alveolar macrophages.
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Affiliation(s)
- Emel Baloglu
- Department of Medical Pharmacology, School of Medicine, Acibadem Mehmet Ali Aydinlar University, 34752 Istanbul, Turkey;
- Translational Lung Research Center Heidelberg (TLRC-H), Part of the German Center for Lung Research (DZL), 69120 Heidelberg, Germany; (K.V.); (E.E.-K.)
| | - Kalpana Velineni
- Translational Lung Research Center Heidelberg (TLRC-H), Part of the German Center for Lung Research (DZL), 69120 Heidelberg, Germany; (K.V.); (E.E.-K.)
| | - Ezgi Ermis-Kaya
- Translational Lung Research Center Heidelberg (TLRC-H), Part of the German Center for Lung Research (DZL), 69120 Heidelberg, Germany; (K.V.); (E.E.-K.)
| | - Heimo Mairbäurl
- Translational Lung Research Center Heidelberg (TLRC-H), Part of the German Center for Lung Research (DZL), 69120 Heidelberg, Germany; (K.V.); (E.E.-K.)
- Medical Clinic VII, Sports Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
- Translational Pneumology, University Hospital Heidelberg, 69120 Heidelberg, Germany
- Correspondence: ; Tel.: +49-6221-56-39329
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Cho DY, Zhang S, Lazrak A, Skinner D, Thompson HM, Grayson J, Guroji P, Aggarwal S, Bebok Z, Rowe SM, Matalon S, Sorscher EJ, Woodworth BA. LPS decreases CFTR open probability and mucociliary transport through generation of reactive oxygen species. Redox Biol 2021; 43:101998. [PMID: 33971543 PMCID: PMC8129928 DOI: 10.1016/j.redox.2021.101998] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 04/26/2021] [Indexed: 12/26/2022] Open
Abstract
Lipopolysaccharide (LPS) serves as the interface between gram-negative bacteria (GNB) and the innate immune response in respiratory epithelial cells (REC). Herein, we describe a novel biological role of LPS that permits GNB to persist in the respiratory tract through inducing CFTR and mucociliary dysfunction. LPS reduced cystic fibrosis transmembrane conductance regulater (CFTR)-mediated short-circuit current in mammalian REC in Ussing chambers and nearly abrogated CFTR single channel activity (defined as forskolin-activated Cl- currents) in patch clamp studies, effects of which were blocked with toll-like receptor (TLR)-4 inhibitor. Unitary conductance and single-channel amplitude of CFTR were unaffected, but open probability and number of active channels were markedly decreased. LPS increased cytoplasmic and mitochondrial reactive oxygen species resulting in CFTR carbonylation. All effects of exposure were eliminated when reduced glutathione was added in the medium along with LPS. Functional microanatomy parameters, including mucociliary transport, in human sinonasal epithelial cells in vitro were also decreased, but restored with co-incubation with glutathione or TLR-4 inhibitor. In vivo measurements, following application of LPS in the nasal cavities showed significant decreases in transepithelial Cl- secretion as measured by nasal potential difference (NPD) – an effect that was nullified with glutathione and TLR-4 inhibitor. These data provide definitive evidence that LPS-generated reactive intermediates downregulate CFTR function in vitro and in vivo which results in cystic fibrosis-type disease. Findings have implications for therapeutic approaches intent on stimulating Cl- secretion and/or reducing oxidative stress to decrease the sequelae of GNB airway colonization and infection.
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Affiliation(s)
- Do Yeon Cho
- Department of Otolaryngology Head & Neck Surgery, University of Alabama at Birmingham, Birmingham, AL, USA; Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA; Division of Otolaryngology, Department of Surgery, Veterans Affairs, Birmingham, AL, USA
| | - Shaoyan Zhang
- Department of Otolaryngology Head & Neck Surgery, University of Alabama at Birmingham, Birmingham, AL, USA; Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Ahmed Lazrak
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Daniel Skinner
- Department of Otolaryngology Head & Neck Surgery, University of Alabama at Birmingham, Birmingham, AL, USA; Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Harrison M Thompson
- Department of Otolaryngology Head & Neck Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jessica Grayson
- Department of Otolaryngology Head & Neck Surgery, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Purushotham Guroji
- Department of Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Saurabh Aggarwal
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Zsuzsanna Bebok
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Steven M Rowe
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Sadis Matalon
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Eric J Sorscher
- Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Bradford A Woodworth
- Department of Otolaryngology Head & Neck Surgery, University of Alabama at Birmingham, Birmingham, AL, USA; Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA.
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McEvoy-May JH, Jones DE, Stoa L, Dixon DL, Tai TC, Hooker AM, Boreham DR, Wilson JY. Unchanged cardiovascular and respiratory outcomes in healthy C57Bl/6 mice after in utero exposure to ionizing radiation. Int J Radiat Biol 2020; 97:131-138. [PMID: 33258723 DOI: 10.1080/09553002.2021.1855372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
BACKGROUND Advancements in medical technologies that utilize ionizing radiation have led to improved diagnosis and patient outcomes, however, the effect of ionizing radiation on the patient is still debated. In the case of pregnancy, the potential effects are not only to the mother but also to the fetus. The aim of this study was to determine if exposure from ionizing radiation during pregnancy alters the development of the cardiovascular and respiratory system of the offspring. MATERIALS AND METHODS Pregnant C57Bl/6 mice were whole-body irradiated at gestational day 15 with a 137Cs gamma radiation emitting source at 0 mGy (sham), 50 mGy, 300 mGy, or 1000 mGy. Post weaning weight and blood pressure measurements were taken weekly for both male and female pups until euthanasia at 16-17 weeks postnatal age. Immediately following, the trachea was cannulated, and the lungs and heart excised. The lung was then examined to assess respiratory physiological outcomes. RESULTS AND CONCLUSIONS In utero exposures to 1000 mGy caused significant growth reduction compared to sham irradiated, which remained persistent for both male and female pups. Growth restriction was not observed for lower exposures. There was no significant change in any cardiovascular or respiratory outcomes measured. Overall, intrauterine exposures to ionizing radiation does not appear to significantly alter the development of the cardiovascular and respiratory system in C57Bl/6 pups up to 17 weeks postnatal age.
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Affiliation(s)
- James H McEvoy-May
- Flinders Health and Medical Research Institute, Flinders University, Adelaide, South Australia, Australia.,Department of Biology, McMaster University, Hamilton, Ontario, Canada.,Centre for Radiation Research, Education and Innovation, University of Adelaide, Adelaide, South Australia, Australia
| | - Devon E Jones
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Lisa Stoa
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Dani-Louise Dixon
- Flinders Health and Medical Research Institute, Flinders University, Adelaide, South Australia, Australia.,Centre for Radiation Research, Education and Innovation, University of Adelaide, Adelaide, South Australia, Australia.,Medical Sciences Division, Northern Ontario School of Medicine, Sudbury, Ontario, Canada
| | - T C Tai
- Medical Sciences Division, Northern Ontario School of Medicine, Sudbury, Ontario, Canada
| | - Antony M Hooker
- Flinders Health and Medical Research Institute, Flinders University, Adelaide, South Australia, Australia.,Centre for Radiation Research, Education and Innovation, University of Adelaide, Adelaide, South Australia, Australia
| | - Douglas R Boreham
- Medical Sciences Division, Northern Ontario School of Medicine, Sudbury, Ontario, Canada
| | - Joanna Y Wilson
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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Efficacy of Quercetin as a potent sensitizer of β2-AR in combating the impairment of fluid clearance in lungs of rats under hypoxia. Respir Physiol Neurobiol 2020; 273:103334. [DOI: 10.1016/j.resp.2019.103334] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 10/08/2019] [Accepted: 10/20/2019] [Indexed: 12/12/2022]
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Downs CA, Kreiner L, Zhao XM, Trac P, Johnson NM, Hansen JM, Brown LA, Helms MN. Oxidized glutathione (GSSG) inhibits epithelial sodium channel activity in primary alveolar epithelial cells. Am J Physiol Lung Cell Mol Physiol 2015; 308:L943-52. [PMID: 25713321 PMCID: PMC4888545 DOI: 10.1152/ajplung.00213.2014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 02/15/2015] [Indexed: 11/22/2022] Open
Abstract
Amiloride-sensitive epithelial Na(+) channels (ENaC) regulate fluid balance in the alveoli and are regulated by oxidative stress. Since glutathione (GSH) is the predominant antioxidant in the lungs, we proposed that changes in glutathione redox potential (Eh) would alter cell signaling and have an effect on ENaC open probability (Po). In the present study, we used single channel patch-clamp recordings to examine the effect of oxidative stress, via direct application of glutathione disulfide (GSSG), on ENaC activity. We found a linear decrease in ENaC activity as the GSH/GSSG Eh became less negative (n = 21; P < 0.05). Treatment of 400 μM GSSG to the cell bath significantly decreased ENaC Po from 0.39 ± 0.06 to 0.13 ± 0.05 (n = 8; P < 0.05). Likewise, back-filling recording electrodes with 400 μM GSSG reduced ENaC Po from 0.32 ± 0.08 to 0.17 ± 0.05 (n = 10; P < 0.05), thus implicating GSSG as an important regulatory factor. Biochemical assays indicated that oxidizing potentials promote S-glutathionylation of ENaC and irreversible oxidation of cysteine residues with N-ethylmaleimide blocked the effects of GSSG on ENaC Po. Additionally, real-time imaging studies showed that GSSG impairs alveolar fluid clearance in vivo as opposed to GSH, which did not impair clearance. Taken together, these data show that glutathione Eh is an important determinant of alveolar fluid clearance in vivo.
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Affiliation(s)
- Charles A Downs
- Nell Hodgson Woodruff School of Nursing, Emory University, Atlanta, Georgia
| | - Lisa Kreiner
- Department Pediatrics, School of Medicine, Emory University, Atlanta, Georgia
| | - Xing-Ming Zhao
- Department of Computer Science, School of Electronics and Information Engineering, Tongji University, Shanghai, China
| | - Phi Trac
- Department Pediatrics, School of Medicine, Emory University, Atlanta, Georgia
| | - Nicholle M Johnson
- Department Pediatrics, School of Medicine, Emory University, Atlanta, Georgia
| | - Jason M Hansen
- Department Pediatrics, School of Medicine, Emory University, Atlanta, Georgia; Center for Cystic Fibrosis and Airways Disease Research at Children's Healthcare of Atlanta Hospital, Atlanta, Georgia; and
| | - Lou Ann Brown
- Department Pediatrics, School of Medicine, Emory University, Atlanta, Georgia; Center for Cystic Fibrosis and Airways Disease Research at Children's Healthcare of Atlanta Hospital, Atlanta, Georgia; and
| | - My N Helms
- Department Pediatrics, School of Medicine, Emory University, Atlanta, Georgia; Center for Cystic Fibrosis and Airways Disease Research at Children's Healthcare of Atlanta Hospital, Atlanta, Georgia; and
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LI CHONG, FU JIANHUA, LIU HONGYU, YANG HAIPING, YAO LI, YOU KAI, XUE XINDONG. Hyperoxia arrests pulmonary development in newborn rats via disruption of endothelial tight junctions and downregulation of Cx40. Mol Med Rep 2014; 10:61-7. [PMID: 24789212 PMCID: PMC4068730 DOI: 10.3892/mmr.2014.2192] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 03/17/2014] [Indexed: 11/17/2022] Open
Abstract
This study investigated changes in vascular endothelial cell tight junction structure and the expression of the gene encoding connexin 40 (Cx40) at the early pneumonedema stage of hyperoxia‑induced bronchopulmonary dysplasia (BPD) in a newborn rat model. A total of 96 newborn rats were randomly assigned to one of the following two groups, the hyperoxia group (n=48) and the control group (n=48). A hyperoxia-induced BPD model was established for the first group, while rats in the control group were maintained under normoxic conditions. Extravasation of Evans Blue (EB) was measured; the severity of lung injury was assessed; a transmission electron microscope (TEM) was used to examine the vascular endothelial cell tight junction structures, and immunohistochemical assay, western blotting and reverse transcription-polymerase chain reaction (RT-PCR) were used to evaluate the expression of Cx40 at the mRNA and protein level. Our findings showed that injuries due to BPD are progressively intensified during the time-course of exposure to hyperoxic conditions. Pulmonary vascular permeability in the hyperoxia group reached the highest level at day 5, and was significantly higher compared to the control group. TEM observations demonstrated tight junctions between endothelial cells were extremely tight. In the hyperoxia group, no marked changes in the tight junction structure were found at days 1 and 3; paracellular gaps were visible between endothelial cells at days 5 and 7. Immunohistochemical staining revealed that the Cx40 protein is mainly expressed in the vascular endothelial cells of lung tissue. Western blotting and RT-PCR assays showed a gradual decrease in Cx40 expression, depending on the exposure time to hyperoxic conditions. However, the Cx40 mRNA level reached a trough at 5 days. Overall, our study demonstrated that exposure to hyperoxia damages the tight junction structures between vascular endothelial cells and downregulates Cx40. We therefore conclude that hyperoxia may participate in the regulation of pulmonary vascular endothelial permeability.
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Affiliation(s)
- CHONG LI
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - JIANHUA FU
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - HONGYU LIU
- Department of Emergency, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - HAIPING YANG
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - LI YAO
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - KAI YOU
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - XINDONG XUE
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
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TGF-β directs trafficking of the epithelial sodium channel ENaC which has implications for ion and fluid transport in acute lung injury. Proc Natl Acad Sci U S A 2013; 111:E374-83. [PMID: 24324142 DOI: 10.1073/pnas.1306798111] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
TGF-β is a pathogenic factor in patients with acute respiratory distress syndrome (ARDS), a condition characterized by alveolar edema. A unique TGF-β pathway is described, which rapidly promoted internalization of the αβγ epithelial sodium channel (ENaC) complex from the alveolar epithelial cell surface, leading to persistence of pulmonary edema. TGF-β applied to the alveolar airspaces of live rabbits or isolated rabbit lungs blocked sodium transport and caused fluid retention, which--together with patch-clamp and flow cytometry studies--identified ENaC as the target of TGF-β. TGF-β rapidly and sequentially activated phospholipase D1, phosphatidylinositol-4-phosphate 5-kinase 1α, and NADPH oxidase 4 (NOX4) to produce reactive oxygen species, driving internalization of βENaC, the subunit responsible for cell-surface stability of the αβγENaC complex. ENaC internalization was dependent on oxidation of βENaC Cys(43). Treatment of alveolar epithelial cells with bronchoalveolar lavage fluids from ARDS patients drove βENaC internalization, which was inhibited by a TGF-β neutralizing antibody and a Tgfbr1 inhibitor. Pharmacological inhibition of TGF-β signaling in vivo in mice, and genetic ablation of the nox4 gene in mice, protected against perturbed lung fluid balance in a bleomycin model of lung injury, highlighting a role for both proximal and distal components of this unique ENaC regulatory pathway in lung fluid balance. These data describe a unique TGF-β-dependent mechanism that regulates ion and fluid transport in the lung, which is not only relevant to the pathological mechanisms of ARDS, but might also represent a physiological means of acutely regulating ENaC activity in the lung and other organs.
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Abstract
Ion channels perform a variety of cellular functions in lung epithelia. Oxidant- and antioxidant-mediated mechanisms (that is, redox regulation) of ion channels are areas of intense research. Significant progress has been made in our understanding of redox regulation of ion channels since the last Experimental Biology report in 2003. Advancements include: 1) identification of nonphagocytic NADPH oxidases as sources of regulated reactive species (RS) production in epithelia, 2) an understanding that excessive treatment with antioxidants can result in greater oxidative stress, and 3) characterization of novel RS signaling pathways that converge upon ion channel regulation. These advancements, as discussed at the 2013 Experimental Biology Meeting in Boston, MA, impact our understanding of oxidative stress in the lung, and, in particular, illustrate that the redox state has profound effects on ion channel and cellular function.
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Kuipers MT, Aslami H, Vlaar APJ, Juffermans NP, Tuip-de Boer AM, Hegeman MA, Jongsma G, Roelofs JJTH, van der Poll T, Schultz MJ, Wieland CW. Pre-treatment with allopurinol or uricase attenuates barrier dysfunction but not inflammation during murine ventilator-induced lung injury. PLoS One 2012; 7:e50559. [PMID: 23226314 PMCID: PMC3511544 DOI: 10.1371/journal.pone.0050559] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 10/22/2012] [Indexed: 12/24/2022] Open
Abstract
Introduction Uric acid released from injured tissue is considered a major endogenous danger signal and local instillation of uric acid crystals induces acute lung inflammation via activation of the NLRP3 inflammasome. Ventilator-induced lung injury (VILI) is mediated by the NLRP3 inflammasome and increased uric acid levels in lung lavage fluid are reported. We studied levels in human lung injury and the contribution of uric acid in experimental VILI. Methods Uric acid levels in lung lavage fluid of patients with acute lung injury (ALI) were determined. In a different cohort of cardiac surgery patients, uric acid levels were correlated with pulmonary leakage index. In a mouse model of VILI the effect of allopurinol (inhibits uric acid synthesis) and uricase (degrades uric acid) pre-treatment on neutrophil influx, up-regulation of adhesion molecules, pulmonary and systemic cytokine levels, lung pathology, and regulation of receptors involved in the recognition of uric acid was studied. In addition, total protein and immunoglobulin M in lung lavage fluid and pulmonary wet/dry ratios were measured as markers of alveolar barrier dysfunction. Results Uric acid levels increased in ALI patients. In cardiac surgery patients, elevated levels correlated significantly with the pulmonary leakage index. Allopurinol or uricase treatment did not reduce ventilator-induced inflammation, IκB-α degradation, or up-regulation of NLRP3, Toll-like receptor 2, and Toll-like receptor 4 gene expression in mice. Alveolar barrier dysfunction was attenuated which was most pronounced in mice pre-treated with allopurinol: both treatment strategies reduced wet/dry ratio, allopurinol also lowered total protein and immunoglobulin M levels. Conclusions Local uric acid levels increase in patients with ALI. In mice, allopurinol and uricase attenuate ventilator-induced alveolar barrier dysfunction.
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Affiliation(s)
- Maria T Kuipers
- Laboratory of Experimental Intensive Care and Anesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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Matthay MA, Ware LB, Zimmerman GA. The acute respiratory distress syndrome. J Clin Invest 2012; 122:2731-40. [PMID: 22850883 DOI: 10.1172/jci60331] [Citation(s) in RCA: 1306] [Impact Index Per Article: 108.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The acute respiratory distress syndrome (ARDS) is an important cause of acute respiratory failure that is often associated with multiple organ failure. Several clinical disorders can precipitate ARDS, including pneumonia, sepsis, aspiration of gastric contents, and major trauma. Physiologically, ARDS is characterized by increased permeability pulmonary edema, severe arterial hypoxemia, and impaired carbon dioxide excretion. Based on both experimental and clinical studies, progress has been made in understanding the mechanisms responsible for the pathogenesis and the resolution of lung injury, including the contribution of environmental and genetic factors. Improved survival has been achieved with the use of lung-protective ventilation. Future progress will depend on developing novel therapeutics that can facilitate and enhance lung repair.
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Affiliation(s)
- Michael A Matthay
- Cardiovascular Research Institute and Departments of Medicine and Anesthesia, UCSF, San Francisco, CA, USA.
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