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The Effect of Modified Porcine Surfactant Alone or in Combination with Polymyxin B on Lung Homeostasis in LPS-Challenged and Mechanically Ventilated Adult Rats. Molecules 2020; 25:molecules25194356. [PMID: 32977392 PMCID: PMC7582504 DOI: 10.3390/molecules25194356] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/20/2020] [Accepted: 09/21/2020] [Indexed: 01/21/2023] Open
Abstract
The study aimed to prove the hypothesis that exogenous surfactant and an antibiotic polymyxin B (PxB) can more effectively reduce lipopolysaccharide (LPS)-induced acute lung injury (ALI) than surfactant treatment alone, and to evaluate the effect of this treatment on the gene expression of surfactant proteins (SPs). Anesthetized rats were intratracheally instilled with different doses of LPS to induce ALI. Animals with LPS 500 μg/kg have been treated with exogenous surfactant (poractant alfa, Curosurf®, 50 mg PL/kg b.w.) or surfactant with PxB 1% w.w. (PSUR + PxB) and mechanically ventilated for 5 hrs. LPS at 500 μg/kg increased lung edema, oxidative stress, and the levels of proinflammatory mediators in lung tissue and bronchoalveolar lavage fluid (BALF). PSUR reduced lung edema and oxidative stress in the lungs and IL-6 in BALF. This effect was further potentiated by PxB added to PSUR. Exogenous surfactant enhanced the gene expression of SP-A, SP-B, and SP-C, however, gene expression for all SPs was reduced after treatment with PSUR + PxB. In mechanically ventilated rats with LPS-induced ALI, the positive effect of exogenous surfactant on inflammation and oxidative stress was potentiated with PxB. Due to the tendency for reduced SPs gene expression after surfactant/PxB treatment topical use of PxB should be considered with caution.
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Staphylococcus aureus Lung Infection Results in Down-Regulation of Surfactant Protein-A Mainly Caused by Pro-Inflammatory Macrophages. Microorganisms 2020; 8:microorganisms8040577. [PMID: 32316261 PMCID: PMC7232181 DOI: 10.3390/microorganisms8040577] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/07/2020] [Accepted: 04/14/2020] [Indexed: 01/21/2023] Open
Abstract
Pneumonia is the leading cause of hospitalization worldwide. Besides viruses, bacterial co-infections dramatically exacerbate infection. In general, surfactant protein-A (SP-A) represents a first line of immune defense. In this study, we analyzed whether influenza A virus (IAV) and/or Staphylococcus aureus (S. aureus) infections affect SP-A expression. To closely reflect the situation in the lung, we used a human alveolus-on-a-chip model and a murine pneumonia model. Our results show that S. aureus can reduce extracellular levels of SP-A, most likely attributed to bacterial proteases. Mono-epithelial cell culture experiments reveal that the expression of SP-A is not directly affected by IAV or S. aureus. Yet, the mRNA expression of SP-A is strongly down-regulated by TNF-α, which is highly produced by professional phagocytes in response to bacterial infection. By using the human alveolus-on-a-chip model, we show that the down-regulation of SP-A is strongly dependent on macrophages. In a murine model of pneumonia, we can confirm that S. aureus decreases SP-A levels in vivo. These findings indicate that (I) complex interactions of epithelial and immune cells induce down-regulation of SP-A expression and (II) bacterial mono- and super-infections reduce SP-A expression in the lung, which might contribute to a severe outcome of bacterial pneumonia.
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Arai Y, Ito M, Tanaka K, Ozawa J, Motojima Y, Matsuoka K, Igarashi K, Namba F. Increased expression of heme oxygenase-1 suppresses airway branching morphogenesis in fetal mouse lungs exposed to inflammation. Pediatr Res 2020; 87:494-500. [PMID: 31578032 DOI: 10.1038/s41390-019-0588-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 09/04/2019] [Accepted: 09/09/2019] [Indexed: 11/09/2022]
Abstract
BACKGROUND Intrauterine inflammation affects fetal lung development. BTB and CNC homology 1 (Bach1) is a transcriptional repressor of heme oxygenase-1 (HO-1) and interleukin-6 (IL-6) genes. We investigated the role of Bach1 in the development of fetal mouse lungs exposed to lipopolysaccharide (LPS) using a whole fetal lung tissue culture system. METHODS We isolated and cultured embryonic day 12.5 fetal mouse lungs from pregnant Bach1 knockout (-/-) and wild-type (WT) mice. Airway branching morphogenesis was assessed by microscopically counting peripheral lung buds after incubation with/without LPS. Expression levels of genes related to inflammation and oxidative stress were evaluated using quantitative PCR. Zinc protoporphyrin, HO-1-specific inhibitor, was used. RESULTS Branching morphogenesis was observed in Bach1-/- and WT fetal mice lungs without LPS exposure; after exposure to LPS, the number of peripheral lung buds was suppressed in Bach1-/- group only. Basal messenger RNA (mRNA) and protein expression of HO-1 was significantly higher in Bach1-/- group than in WT group; IL-6 and monocyte chemoattractant protein-1 mRNA expression was significantly increased after LPS exposure in both groups. Zinc protoporphyrin mitigated the LPS-induced suppression of branching morphogenesis in Bach1-/- mice. CONCLUSION The ablation of Bach1 suppresses airway branching morphogenesis after LPS exposure by increased basal expression levels of HO-1.
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Affiliation(s)
- Yukio Arai
- Department of Pediatrics, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, 350-8550, Japan
| | - Masato Ito
- Department of Pediatrics, Akita University Graduate School of Medicine, Akita, Akita, 010-8543, Japan
| | - Kosuke Tanaka
- Department of Pediatrics, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, 350-8550, Japan
| | - Junichi Ozawa
- Department of Pediatrics, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, 350-8550, Japan
| | - Yukiko Motojima
- Department of Pediatrics, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, 350-8550, Japan
| | - Kikumi Matsuoka
- Department of Pediatrics, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, 350-8550, Japan
| | - Kazuhiko Igarashi
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8575, Japan
| | - Fumihiko Namba
- Department of Pediatrics, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, 350-8550, Japan.
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Knockdown of LncRNA MALAT1 contributes to cell apoptosis via regulating NF-κB/CD80 axis in neonatal respiratory distress syndrome. Int J Biochem Cell Biol 2018; 104:138-148. [PMID: 30243953 DOI: 10.1016/j.biocel.2018.09.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/16/2018] [Accepted: 09/18/2018] [Indexed: 01/28/2023]
Abstract
Neonatal respiratory distress syndrome (NRDS) is a leading cause of morbidity in premature newborns and is a common reason for admission to the neonatal intensive care unit (NICU). Recent studies found that the pathogenesis of NRDS is not simply lung immaturity. Apoptosis is an essential process for the development and maturation of the lungs. In this study, we report a critical role of lncRNA MALAT1 in regulating CD80 transcription in the NRDS-associated apoptosis via binding with NF-κB. We first showed MALAT1 and CD80 were highly expressed in the peripheral blood mononuclear cells of NRDS with infection exposure. Then we found MALAT1 expressions were significantly increased by the treatment of LPS. We confirmed knockdown of MALAT1 promoted cell viability by CCK-8 assays, cell apoptosis by flow cytometric assays and cytoskeleton destruction by immunocytochemistry. We confirmed CD80 expression level was associated with cell apoptosis by affecting PARP and caspase-3. Then we demonstrated knockdown of MALAT1 promoted CD80 transcription in A549 cells. Furthermore, we confirmed that MALAT1 downregulated transcriptional expression of CD80 by interfering with NF-κB activation and disrupting its binding efficiency with the CD80 promoter in the cell nucleus. In conclusion, we first identified lncRNA MALAT1 as an important prognosis maker for NRDS patients. Most significantly, this study then demonstrated a novel regulatory function of knocked-down MALAT1 on the transcriptional level of CD80 by enhancing the binding of NF-κB to CD80 promoter. Since the interaction between MALAT1 and CD80 plays an essential role in the cell apoptosis of NRDS, our findings demonstrate the possibility of using MALAT1 as therapeutic target for treatment of NRDS, and extend existing knowledge about the molecular mechanism that underlies NRDS pathogensis.
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Visconti K, Senthamaraikannan P, Kemp MW, Saito M, Kramer BW, Newnham JP, Jobe AH, Kallapur SG. Extremely preterm fetal sheep lung responses to antenatal steroids and inflammation. Am J Obstet Gynecol 2018; 218:349.e1-349.e10. [PMID: 29274832 DOI: 10.1016/j.ajog.2017.12.207] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 11/27/2017] [Accepted: 12/14/2017] [Indexed: 11/25/2022]
Abstract
BACKGROUND The efficacy of antenatal steroids for fetal lung maturation in the periviable period is not fully understood. OBJECTIVE We sought to determine the lung maturational effects of antenatal steroids and inflammation in early gestation sheep fetuses, similar to the periviable period in human beings. STUDY DESIGN Date-mated ewes with singleton fetuses were randomly assigned to 1 of 4 treatment groups (n = 8/group): (1) maternal intramuscular injection of betamethasone; (2) intraamniotic lipopolysaccharide; (3) betamethasone + lipopolysaccharide; and (4) intraamniotic + intramuscular saline (controls). Fetuses were delivered surgically 48 hours later at 94 days' gestation (63% term gestation) for comprehensive evaluations of lung maturation, and lung and systemic inflammation. RESULTS Relative to controls, first, betamethasone increased the fetal lung air space to mesenchymal area ratio by 47% but did not increase the messenger RNAs for the surfactant proteins-B and -C that are important for surfactant function or increase the expression of pro-surfactant protein-C in the alveolar type II cells. Second, betamethasone increased expression of 1 of the 4 genes in surfactant lipid synthetic pathways. Third, betamethasone increased genes involved in epithelium sodium channel transport, but not sodium-potassium adenosine triphosphatase or Aquaporin 5. Fourth, lipopolysaccharide increased proinflammatory genes in the lung but did not effectively recruit activated inflammatory cells. Last, betamethasone incompletely suppressed lipopolysaccharide-induced lung inflammation. In the liver, betamethasone when given alone increased the expression of serum amyloid A3 and C-reactive protein messenger RNAs. CONCLUSION Compared the more mature 125-day gestation sheep, antenatal steroids do not induce pulmonary surfactants during the periviable period, indicating a different response.
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Bartolák-Suki E, Noble PB, Bou Jawde S, Pillow JJ, Suki B. Optimization of Variable Ventilation for Physiology, Immune Response and Surfactant Enhancement in Preterm Lambs. Front Physiol 2017; 8:425. [PMID: 28690548 PMCID: PMC5481362 DOI: 10.3389/fphys.2017.00425] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 06/01/2017] [Indexed: 12/12/2022] Open
Abstract
Preterm infants often require mechanical ventilation due to lung immaturity including reduced or abnormal surfactant. Since cyclic stretch with cycle-by-cycle variability is known to augment surfactant release by epithelial cells, we hypothesized that such in vivo mechanotransduction improves surfactant maturation and hence lung physiology in preterm subjects. We thus tested whether breath-by-breath variability in tidal volume (VT) in variable ventilation (VV) can be tuned for optimal performance in a preterm lamb model. Preterm lambs were ventilated for 3 h with conventional ventilation (CV) or two variants of VV that used a maximum VT of 1.5 (VV1) or 2.25 (VV2) times the mean VT. VT was adjusted during ventilation to a permissive pCO2 target range. Respiratory mechanics were monitored continuously using the forced oscillation technique, followed by postmortem bronchoalveolar lavage and tissue collection. Both VVs outperformed CV in blood gas parameters (pH, SaO2, cerebral O2 saturation). However, only VV2 lowered PaCO2 and had a higher specific respiratory compliance than CV. VV2 also increased surfactant protein (SP)-B release compared to VV1 and stimulated its production compared to CV. The production and release of proSP-C however, was increased with CV compared to both VVs. There was more SP-A in both VVs than CV in the lung, but VV2 downregulated SP-A in the lavage, whereas SP-D significantly increased in CV in both the lavage and lung. Compared to CV, the cytokines IL-1β, and TNFα decreased with both VVs with less inflammation during VV2. Additionally, VV2 lungs showed the most homogeneous alveolar structure and least inflammatory cell infiltration assessed by histology. CV lungs exhibited over-distension mixed with collapsed and interstitial edematous regions with occasional hemorrhage. Following VV1, some lambs had normal alveolar structure while others were similar to CV. The IgG serum proteins in the lavage, a marker of leakage, were the highest in CV. An overall combined index of performance that included physiological, biochemical and histological markers was the best in VV2 followed by VV1. Thus, VV2 outperformed VV1 by enhancing SP-B metabolism resulting in open alveolar airspaces, less leakage and inflammation and hence better respiratory mechanics.
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Affiliation(s)
| | - Peter B Noble
- Anatomy, Physiology and Human Biology, School of Human Sciences, University of Western AustraliaPerth, WA, Australia.,Centre of Neonatal Research and Education, Pediatrics, Medical School, University of Western AustraliaPerth, WA, Australia
| | - Samer Bou Jawde
- Department of Biomedical Engineering, Boston UniversityBoston, MA, United States
| | - Jane J Pillow
- Anatomy, Physiology and Human Biology, School of Human Sciences, University of Western AustraliaPerth, WA, Australia.,Centre of Neonatal Research and Education, Pediatrics, Medical School, University of Western AustraliaPerth, WA, Australia
| | - Béla Suki
- Department of Biomedical Engineering, Boston UniversityBoston, MA, United States
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Vieira F, Kung JW, Bhatti F. Structure, genetics and function of the pulmonary associated surfactant proteins A and D: The extra-pulmonary role of these C type lectins. Ann Anat 2017; 211:184-201. [PMID: 28351530 DOI: 10.1016/j.aanat.2017.03.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 10/19/2022]
Abstract
The collectins family encompasses several collagenous Ca2+-dependent defense lectins that are described as pathogen recognition molecules. They play an important role in both adaptive and innate immunity. Surfactant proteins A and D are two of these proteins which were initially discovered in association with surfactant in the pulmonary system. The structure, immune and inflammatory functions, and genetic variations have been well described in relation to their roles, function and pathophysiology in the pulmonary system. Subsequently, these proteins have been discovered in a wide range of other organs and organ systems. The role of these proteins outside the pulmonary system is currently an active area of research. This review intends to provide a current overview of the genetics, structure and extra-pulmonary functions of the surfactant collectin proteins.
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Affiliation(s)
- Frederico Vieira
- Neonatal Perinatal Medicine, Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.
| | - Johannes W Kung
- Neonatal Perinatal Medicine, Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.
| | - Faizah Bhatti
- Neonatal Perinatal Medicine, Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States; Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States; Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.
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8
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Weitnauer M, Mijošek V, Dalpke AH. Control of local immunity by airway epithelial cells. Mucosal Immunol 2016; 9:287-98. [PMID: 26627458 DOI: 10.1038/mi.2015.126] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 10/25/2015] [Indexed: 02/04/2023]
Abstract
The lung is ventilated by thousand liters of air per day. Inevitably, the respiratory system comes into contact with airborne microbial compounds, most of them harmless contaminants. Airway epithelial cells are known to have innate sensor functions, thus being able to detect microbial danger. To avoid chronic inflammation, the pulmonary system has developed specific means to control local immune responses. Even though airway epithelial cells can act as proinflammatory promoters, we propose that under homeostatic conditions airway epithelial cells are important modulators of immune responses in the lung. In this review, we discuss epithelial cell regulatory functions that control reactivity of professional immune cells within the microenvironment of the airways and how these mechanisms are altered in pulmonary diseases. Regulation by epithelial cells can be divided into two mechanisms: (1) mediators regulate epithelial cells' innate sensitivity in cis and (2) factors are produced that limit reactivity of immune cells in trans.
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Affiliation(s)
- M Weitnauer
- Department of Infectious Diseases, Medical Microbiology and Hygiene, University Hospital Heidelberg, Heidelberg, Germany
| | - V Mijošek
- Department of Infectious Diseases, Medical Microbiology and Hygiene, University Hospital Heidelberg, Heidelberg, Germany
| | - A H Dalpke
- Department of Infectious Diseases, Medical Microbiology and Hygiene, University Hospital Heidelberg, Heidelberg, Germany.,Translational Lung Research Center (TLRC), Member of the German Center for Lung Research (DZL), Heidelberg, Germany
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9
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Tsotakos N, Silveyra P, Lin Z, Thomas N, Vaid M, Floros J. Regulation of translation by upstream translation initiation codons of surfactant protein A1 splice variants. Am J Physiol Lung Cell Mol Physiol 2014; 308:L58-75. [PMID: 25326576 DOI: 10.1152/ajplung.00058.2014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Surfactant protein A (SP-A), a molecule with roles in lung innate immunity and surfactant-related functions, is encoded by two genes in humans: SFTPA1 (SP-A1) and SFTPA2 (SP-A2). The mRNAs from these genes differ in their 5'-untranslated regions (5'-UTR) due to differential splicing. The 5'-UTR variant ACD' is exclusively found in transcripts of SP-A1, but not in those of SP-A2. Its unique exon C contains two upstream AUG codons (uAUGs) that may affect SP-A1 translation efficiency. The first uAUG (u1) is in frame with the primary start codon (p), but the second one (u2) is not. The purpose of this study was to assess the impact of uAUGs on SP-A1 expression. We employed RT-qPCR to determine the presence of exon C-containing SP-A1 transcripts in human RNA samples. We also used in vitro techniques including mutagenesis, reporter assays, and toeprinting analysis, as well as in silico analyses to determine the role of uAUGs. Exon C-containing mRNA is present in most human lung tissue samples and its expression can, under certain conditions, be regulated by factors such as dexamethasone or endotoxin. Mutating uAUGs resulted in increased luciferase activity. The mature protein size was not affected by the uAUGs, as shown by a combination of toeprint and in silico analysis for Kozak sequence, secondary structure, and signal peptide and in vitro translation in the presence of microsomes. In conclusion, alternative splicing may introduce uAUGs in SP-A1 transcripts, which in turn negatively affect SP-A1 translation, possibly affecting SP-A1/SP-A2 ratio, with potential for clinical implication.
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Affiliation(s)
- Nikolaos Tsotakos
- Center for Host Defense, Inflammation and Lung Disease (CHILD) Research, Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Patricia Silveyra
- Center for Host Defense, Inflammation and Lung Disease (CHILD) Research, Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Zhenwu Lin
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Neal Thomas
- Center for Host Defense, Inflammation and Lung Disease (CHILD) Research, Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; Department of Public Health Sciences, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and
| | - Mudit Vaid
- Center for Host Defense, Inflammation and Lung Disease (CHILD) Research, Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Joanna Floros
- Center for Host Defense, Inflammation and Lung Disease (CHILD) Research, Department of Pediatrics, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; Department of Obstetrics and Gynecology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania
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Atik A, Sozo F, Orgeig S, Suri L, Hanita T, Harding R, De Matteo R. Long-Term Pulmonary Effects of Intrauterine Exposure to Endotoxin Following Preterm Birth in Sheep. Reprod Sci 2012; 19:1352-64. [DOI: 10.1177/1933719112450327] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Anzari Atik
- Department of Anatomy & Developmental Biology, Monash University, Clayton, Australia
| | - Foula Sozo
- Department of Anatomy & Developmental Biology, Monash University, Clayton, Australia
| | - Sandra Orgeig
- Sansom Institute for Health Research and School of Pharmacy & Medical Sciences, University of South Australia, Adelaide, Australia
| | - Lakshmi Suri
- Sansom Institute for Health Research and School of Pharmacy & Medical Sciences, University of South Australia, Adelaide, Australia
| | - Takushi Hanita
- Department of Anatomy & Developmental Biology, Monash University, Clayton, Australia
| | - Richard Harding
- Department of Anatomy & Developmental Biology, Monash University, Clayton, Australia
| | - Robert De Matteo
- Department of Anatomy & Developmental Biology, Monash University, Clayton, Australia
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Höhne K, Schließmann SJ, Kirschbaum A, Plönes T, Müller-Quernheim J, Tenor H, Zissel G. Roflumilast-N-oxide induces surfactant protein expression in human alveolar epithelial cells type II. PLoS One 2012; 7:e38369. [PMID: 22815690 PMCID: PMC3398032 DOI: 10.1371/journal.pone.0038369] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 05/04/2012] [Indexed: 11/18/2022] Open
Abstract
Surfactant proteins (SPs) are important lipoprotein complex components, expressed in alveolar epithelial cells type II (AEC-II), and playing an essential role in maintenance of alveolar integrity and host defence. Because expressions of SPs are regulated by cyclic adenosine monophosphate (cAMP), we hypothesized that phosphodiesterase (PDE) inhibitors, influence SP expression and release. Analysis of PDE activity of our AEC-II preparations revealed that PDE4 is the major cAMP hydrolysing PDE in human adult AEC-II. Thus, freshly isolated human AEC-II were stimulated with two different concentrations of the PDE4 inhibitor roflumilast-N-oxide (3 nM and 1 µM) to investigate the effect on SP expression. SP mRNA levels disclosed a large inter-individual variation. Therefore, the experiments were grouped by the basal SP expression in low and high expressing donors. AEC-II stimulated with Roflumilast-N-oxide showed a minor increase in SP-A1, SP-C and SP-D mRNA mainly in low expressing preparations. To overcome the effects of different basal levels of intracellular cAMP, cyclooxygenase was blocked by indomethacin and cAMP production was reconstituted by prostaglandin E2 (PGE2). Under these conditions SP-A1, SP-A2, SP-B and SP-D are increased by roflumilast-N-oxide in low expressing preparations. Roflumilast-N-oxide fosters the expression of SPs in human AEC-II via increase of intracellular cAMP levels potentially contributing to improved alveolar host defence and enhanced resolution of inflammation.
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Affiliation(s)
- Kerstin Höhne
- Division of Internal Medicine, Department of Pneumology, University Medical Centre, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Stephan J. Schließmann
- Division of Internal Medicine, Department of Pneumology, University Medical Centre, Freiburg, Germany
| | - Andreas Kirschbaum
- Division of Surgery, Department of Thoracic Surgery, University Medical Centre, Freiburg, Germany
| | - Till Plönes
- Division of Surgery, Department of Thoracic Surgery, University Medical Centre, Freiburg, Germany
| | - Joachim Müller-Quernheim
- Division of Internal Medicine, Department of Pneumology, University Medical Centre, Freiburg, Germany
| | - Hermann Tenor
- Nycomed GmbH Global Discovery, Nycomed GmbH, Konstanz, Germany
| | - Gernot Zissel
- Division of Internal Medicine, Department of Pneumology, University Medical Centre, Freiburg, Germany
- * E-mail:
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12
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Kuypers E, Collins JJP, Kramer BW, Ofman G, Nitsos I, Pillow JJ, Polglase GR, Kemp MW, Newnham JP, Gavilanes AWD, Nowacki R, Ikegami M, Jobe AH, Kallapur SG. Intra-amniotic LPS and antenatal betamethasone: inflammation and maturation in preterm lamb lungs. Am J Physiol Lung Cell Mol Physiol 2011; 302:L380-9. [PMID: 22160306 DOI: 10.1152/ajplung.00338.2011] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The proinflammatory stimulus of chorioamnionitis is commonly associated with preterm delivery. Women at risk of preterm delivery receive antenatal glucocorticoids to functionally mature the fetal lung. However, the effects of the combined exposures of chorioamnionitis and antenatal glucocorticoids on the fetus are poorly understood. Time-mated ewes with singleton fetuses received an intra-amniotic injection of lipopolysaccharide (LPS) either preceding or following maternal intramuscular betamethasone 7 or 14 days before delivery, and the fetuses were delivered at 120 days gestational age (GA) (term = 150 days GA). Gestation matched controls received intra-amniotic and maternal intramuscular saline. Compared with saline controls, intra-amniotic LPS increased inflammatory cells in the bronchoalveolar lavage and myeloperoxidase, Toll-like receptor 2 and 4 mRNA, PU.1, CD3, and Foxp3-positive cells in the fetal lung. LPS-induced lung maturation measured as increased airway surfactant and improved lung gas volumes. Intra-amniotic LPS-induced inflammation persisted until 14 days after exposure. Betamethasone treatment alone induced modest lung maturation but, when administered before intra-amniotic LPS, suppressed lung inflammation. Interestingly, betamethasone treatment after LPS did not counteract inflammation but enhanced lung maturation. We conclude that the order of exposures of intra-amniotic LPS or maternal betamethasone had large effects on fetal lung inflammation and maturation.
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Affiliation(s)
- Elke Kuypers
- Department of Pediatrics, School for Oncology and Developmental Biology, Maastricht University Medical Center, The Netherlands
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13
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Zhan CY, Yuan TM, Sun Y, Yu HM. Early gestational intrauterine infection induces postnatal lung inflammation and arrests lung development in a rat model. J Matern Fetal Neonatal Med 2010; 24:213-22. [PMID: 20476872 DOI: 10.3109/14767051003758895] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE In order to investigate the early gestational inflammation effect on the prenatal and postnatal lung development, identification of the proinflammatory cytokines (IL-1β and TNF-α), genes implicated in angiogenesis (Vascular endothelial growth factor [VEGF], fms-like tyrosine kinase-1 [Flt-1], fetal liver kinase-1 [Flk-1]), and surfactant proteins (SPs) were observed. METHODS Escherichia coli (E. coli) was inoculated into uterine cervix of pregnant rats at embryonic day 15 (E15) during pseudoglandular period of lung development and the control group was inoculated with normal saline. IL-1β, TNF-α, VEGF, Flt-1, Flk-1, SP-A, and SP-B mRNA in pup's lung at E17, 19, 21 and postnatal day (P) 1, 3, 7, 14 were quantified by real-time RT-PCR. Western blot or immunohistochemistry analysis was also performed for the evaluation of VEGF, Flk-1, Flt-1, and SP-A expression in pup's lung. RESULTS Compared with the control group, the fetal lung of the E. coli-treated group was more immature, the postnatal lung development was impaired marked by less alveoli, fewer secondary septa, and thicker alveolar wall. The lung weight and lung/body weight ratio were lower in the E. coli-treated group pups. IL-1β and TNF-α mRNA were increased significantly in E. coli-treated pup's lung after birth, but no significant difference of IL-1β and TNF-α mRNA levels in fetal lung were found between the two groups. SP-A expression was depressed at E17, E19, and E21 after intrauterine E. coli treated, accompanied with lower SP-B mRNA level at E19 and E21. Furthermore, intrauterine E. coli treated reduced the VEGF mRNA and protein levels in the fetal lung at E17 and E19, while the expression of Flt-1 and Flk-1 were higher at P7, P14 and P1, P7, P14, respectively, compared to the controls. CONCLUSIONS These results suggested early gestational intrauterine E. coli infection could induce a postnatal pulmonary inflammation and might arrest the alveolarization in developing lung which was involved with the VEGF signaling. However, intrauterine E. coli infection could not induce the increase of proinflammatory cytokines in fetal lung and might fail to accelerate the maturation of fetal lung.
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Affiliation(s)
- Can-Yang Zhan
- Department of Neonatology, Children's Hospital, Zhejiang University School of Medicine and Zhejiang Key Laboratory for Diagnosis and Therapy of Neonatal Disease, Zhugan Xiang 57, Hangzhou 310003, People's Republic of China
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Lee J, Oh KJ, Yang HJ, Park JS, Romero R, Yoon BH. The importance of intra-amniotic inflammation in the subsequent development of atypical chronic lung disease. J Matern Fetal Neonatal Med 2010; 22:917-23. [PMID: 19718578 DOI: 10.1080/14767050902994705] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To examine whether the intra-amniotic inflammation is a risk factor for the development of atypical chronic lung disease (CLD). STUDY DESIGN A retrospective cohort study was undertaken in 72 patients who delivered preterm neonates (gestational age: 24-32 weeks) within 5 days of amniocentesis and whose neonates subsequently developed CLD. Atypical CLD was defined as CLD without respiratory distress syndrome (RDS). Intra-amniotic inflammation was defined as an elevated amniotic fluid (AF) concentration of matrix metalloproteinase-8 (MMP-8) (>23 ng/ml). RESULTS (1) Atypical CLD was identified in 54.2% (39/72) of cases with CLD; (2) there were no significant differences in the median gestational age at birth and the rate of antenatal corticosteroid use between infants with atypical CLD and CLD with RDS; (3) preterm newborns with atypical CLD had a significantly higher median AF MMP-8 concentration (median 373.1 ng/ml vs. 8.6 ng/ml, p = 0.003) and median AF white blood cell count (median 450.0/mm(3)vs. 5.5/mm(3), p = 0.009), and a higher rate of intra-amniotic inflammation (74.4%vs. 45.5%, p = 0.012) than those with CLD with RDS. CONCLUSION Intra-amniotic inflammation confers a greater risk for atypical CLD than for typical CLD with initial RDS. This novel observation strengthens the importance of prenatal inflammation as a mechanism of lung injury.
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Affiliation(s)
- Joonho Lee
- Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul 110-744, Korea
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15
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Abstract
Prenatal exposure of very low birth weight infants to chronic indolent chorioamnionitis with organisms such as mycoplasma and ureaplasma is frequent. Chorioamnionitis is inconsistently associated with changed risks of respiratory distress syndrome (RDS) or bronchopulmonary dysplasia (BPD), probably because the diagnosis of chorioamnionitis does not quantify the extent or duration of the fetal exposures to infection and inflammation. The correlations between prenatal exposures and postnatal lung disease also are confounded by the imprecision of the diagnoses of RDS and BPD. In animal models, chorioamnionitis caused by pro-inflammatory mediators or live ureaplasma induces lung maturation, but also causes alveolar simplification and vascular injury. Intra-amniotic endotoxin administration also modulates the fetal innate immune system, resulting in maturation of monocytes to alveolar macrophages and the induction or paralysis of inflammatory responses depending on exposure history. Prenatal inflammation can have profound effects on the fetal lung and subsequent immune responses.
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Affiliation(s)
- Boris W. Kramer
- Dep. kindergeneeskunde, Academisch ziekenhuis Maastricht, Postbus 5800, 6202 AZ Maastricht, The Netherlands
| | - Suhas Kallapur
- Cincinnati Children's Hospital, Division of Pulmonary Biology, University of Cincinnati, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - John Newnham
- University of Western Australia, School of Women's & Infants' Health, Perth, Western Australia, Australia
| | - Alan H. Jobe
- Cincinnati Children's Hospital, Division of Pulmonary Biology, University of Cincinnati, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
- Corresponding author. Tel.: (513) 636-8563; fax: (513) 636-8691. E-mail address: (B.W. Kramer)
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Chaiworapongsa T, Hong JS, Hull WM, Romero R, Whitsett JA. Amniotic fluid concentration of surfactant proteins in intra-amniotic infection. J Matern Fetal Neonatal Med 2009; 21:663-70. [PMID: 18828060 DOI: 10.1080/14767050802215664] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Pulmonary surfactant is a complex molecule of lipids and proteins synthesized and secreted by type II alveolar cells into the alveolar epithelial lining. Both lipid and protein components are essential for lung function in postnatal life. Infection is a well-established cause of preterm delivery, and several inflammatory cytokines play a role in the mechanisms of preterm parturition. An increased concentration of inflammatory cytokines in amniotic fluid or fetal plasma has been linked to the onset of preterm parturition and fetal/neonatal injury, including cerebral palsy and chronic lung disease. Experimental evidence indicates that inflammatory mediators also regulate surfactant protein synthesis, and histologic chorioamnionitis is associated with a decreased incidence of hyaline membrane disease in neonates. This study was conducted to determine if amniotic fluid concentrations of surfactant protein (SP)-A, SP-B, and SP-D change in patients with and without intra-amniotic infection (IAI). MATERIALS AND METHODS A case-control study was conducted to determine amniotic fluid concentrations of SP-A, SP-B, SP-D, and total protein in patients who had an amniocentesis performed between 18 and 34 weeks of gestation for the detection of IAI in patients with spontaneous preterm labor with intact membranes (n = 42) and cervical insufficiency prior to the application of cerclage (n = 6). Amniotic fluid samples were selected from a bank of biological specimens and included patients with (n = 16) and without (n = 32) IAI matched for gestational age at amniocentesis. Intra-amniotic infection was defined as a positive amniotic fluid culture for microorganisms. Each group was further subdivided according to a history of corticosteroid administration within 7 days prior to amniocentesis into the following subgroups: (1) patients without IAI who had received antenatal corticosteroids (n = 21), (2) patients with IAI who had received antenatal corticosteroids (n = 9), (3) patients without IAI who had not received antenatal corticosteroids (n = 11), and (4) patients with IAI who had not received antenatal corticosteroids (n = 7). Amniotic fluid was obtained by transabdominal amniocentesis. SP-A, SP-B, and SP-D concentrations in amniotic fluid were determined by enzyme-linked immunosorbent assay (ELISA). Non-parametric statistics were used for analysis. RESULTS Women with IAI had a higher median amniotic fluid concentration of SP-B and of SP-B/total protein, but not other SPs, than those without IAI (both p = 0.03). Among patients who had received antenatal corticosteroids, the median amniotic fluid concentration of SP-B and of SP-B/total protein was significantly higher in patients with IAI than in those without IAI (SP-B, IAI: median 148 ng/mL, range 37.3-809 ng/mL vs. without IAI: median 7.2 ng/mL, range 0-1035 ng/mL; p = 0.005 and SP-B/total protein, IAI: median 14.1 ng/mg, range 4.3-237.5 ng/mg vs. without IAI: median 1.45 ng/mg, range 0-79.5 ng/mg; p = 0.003). Among women who had not received antenatal corticosteroids, the median amniotic fluid concentrations of SP-B and of SP-B/total protein were not significantly different between patients with and without IAI (SP-B, IAI: median 4 ng/mL, range 0-31.4 ng/mL vs. without IAI: median 3.4 ng/mL, range 0-37 ng/mL; p = 0.8 and SP-B/total protein, IAI: median 0.55 ng/mg, range 0-6.96 ng/mg vs. without IAI: median 0.59 ng/mg, range 0-3.28 ng/mg; p = 0.9). The median amniotic fluid concentrations of SP-A, SP-A/total protein, SP-D, and SP-D/total protein were not significantly different between patients with and without IAI whether they received antenatal corticosteroids or not (all p > 0.05). CONCLUSIONS IAI was associated with an increased amniotic fluid concentration of SP-B in patients who received antenatal corticosteroids within 7 days prior to amniocentesis.
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Abstract
INTRODUCTION Antenatal inflammation in utero may be associated with lung injury and subsequent aberrant lung development resulting in bronchopulmonary dysplasia (BPD). BPD has become a developmental disease with a uniform arrest in lung development. STUDY DESIGN The role of antenatal inflammation in the induction of lung injury was explored in a sheep model suitable for the study of lung development with respect to human development. Chorioamnionitis was induced by a single injection of endotoxin into the amniotic cavity under ultrasound guidance. RESULT Endotoxin-induced chorioamnionitis caused a cascade of lung injury, pulmonary inflammation and remodeling in the fetal lung similar to lung injury previously described in adult animal models. The structural changes in the fetal lung after chorioamnionitis showed little to no fibrosis and alveolar/microvascular simplification similar to new BPD. The identified cytokine networks and regulators may explain the absence of fibrosis and lung simplification after strictly intra-uterine inflammation. CONCLUSION The mechanisms of antenatal inflammation in the fetal lung were multifactorial and could be antenatally modulated. Fetal pulmonary inflammation was temporarily suppressed by maternal glucocorticoid therapy. However, pulmonary inflammation could be augmented postnatally by resuscitation, oxygen toxicity, mechanical ventilation and pulmonary and systemic infection, which opens a broad window of clinical options.
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Abstract
Here, we describe the approach of defining the genetic contribution to disease and discuss the polymorphisms of some genes that are associated with respiratory disease. The common allelic variants of SP-A1, SP-A2, SP-B, SP-C, and SP-D genes are associated with respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD), or respiratory syncytial virus (RSV) bronchiolitis. The main SP-A haplotype, interactively with SP-B Ile131Thr polymorphism and with constitutional and environmental factors, influences the risk of RDS. The polymorphisms of SP-A2 and SP-D are associated with the risk of severe RSV. The polymorphism may turn out to be important in susceptibility to influenza virus. The SP-B intron 4 deletion variant is the risk factor of BPD. Understanding the molecular mechanisms behind the hereditary risk may lead to new focused treatment strategies.
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Affiliation(s)
- Mikko Hallman
- Department of Pediatrics and Biocenter Oulu, University of Oulu, Oulu, Finland.
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Rae C, Cherry JI, Land FM, Land SC. Endotoxin-induced nitric oxide production rescues airway growth and maturation in atrophic fetal rat lung explants. Biochem Biophys Res Commun 2006; 349:416-25. [PMID: 16934757 DOI: 10.1016/j.bbrc.2006.08.067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Accepted: 08/12/2006] [Indexed: 11/16/2022]
Abstract
Inflammation induces premature maturation of the fetal lung but the signals causing this effect remain unclear. We determined if nitric oxide (NO) synthesis, evoked by Escherichia coli lipopolysaccharide (LPS, 2 microg ml-1), participated in this process. Fetal rat lung airway surface complexity rose 2.5-fold over 96h in response to LPS and was associated with increased iNOS protein expression and activity. iNOS inhibition by N6-(1-iminoethyl)-L-lysine-2HCl (L-NIL) abolished this and induced airway atrophy similar to untreated explants. Surfactant protein-C (SP-C) expression was also induced by LPS and abolished by L-NIL. As TGFbeta suppresses iNOS activity, we determined if feedback regulation modulated NO-dependent maturation. LPS induced TGFbeta1 release and SMAD4 nuclear translocation 96 h after treatment. Treatment of explants with a blocking antibody against TGFbeta1 sustained NO production and airway morphogenesis whereas recombinant TGFbeta1 antagonized these effects. Feedback regulation of NO synthesis by TGFbeta may, thus, modulate airway branching and maturation of the fetal lung.
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Affiliation(s)
- C Rae
- Division of Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY Scotland, UK
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Hilgendorff A, Doerner M, Rawer D, Leick J, Trotter A, Ebsen M, Ruppert C, Günther A, Gortner L, Reiss I. Effects of a recombinant surfactant protein-C-based surfactant on lung function and the pulmonary surfactant system in a model of meconium aspiration syndrome. Crit Care Med 2006; 34:203-10. [PMID: 16374175 DOI: 10.1097/01.ccm.0000190624.77908.e2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Meconium aspiration syndrome (MAS) remains a relevant cause of neonatal respiratory failure and is characterized by severe impairment of pulmonary gas exchange, surfactant inactivation, and pronounced inflammatory changes. Surfactant administration has been shown as an effective treatment strategy in MAS. The present study aimed at investigating the impact of a recombinant surfactant protein (SP)-C-based surfactant on pulmonary gas exchange and lung function in this model of neonatal lung injury. Furthermore, SP-B and -C were determined on the transcriptional and protein level. DESIGN Laboratory experiment. SETTING University laboratory. SUBJECTS Twenty three newborn piglets (median age 6 days, weight 1900-2500 g). INTERVENTIONS Piglets were intubated and mechanically ventilated and then received 20% sterile meconium (5 mL/kg) for induction of lung injury. After 30 mins, animals were randomized for control (n = 7, MAS controls), recombinant SP-C surfactant (n = 8), or natural surfactant (n = 8). Surfactant preparations were administered as an intratracheal bolus (75 mg/kg), and animals were ventilated for another 330 mins. Nonventilated newborn piglets at term (n = 28; median weight 1484 g, range 720-1990 g) served as a healthy reference group (healthy controls). MEASUREMENTS AND MAIN RESULTS Lung function variables, arterial blood gas samples, and lung tissues were obtained. Expression of SP-B and -C messenger RNA was quantified in left lung lobe tissue using real-time polymerase chain reaction. Protein concentrations were determined by enzyme-linked immunosorbent assay. Scanning electron microscopy and transmission electron microscopy were performed in tissue samples of the right lung lobe. Compared with healthy controls, SP-B messenger RNA expression was significantly increased in MAS (p < .02), whereas SP-C messenger RNA expression was found to be significantly reduced (p < .001). SP concentrations, however, were not significantly different. Although a significant improvement of gas exchange and lung function was observed after surfactant administration in both groups, surfactant messenger RNA expression and protein concentrations were not significantly altered. Scanning and transmission electron microscopy showed severe pulmonary ultrastructural changes after meconium aspiration improving after surfactant treatment. CONCLUSIONS Impairment of lung function in MAS, associated with marked changes in SP messenger RNA expression, can be sufficiently treated using recombinant SP-C-based or natural surfactant. Despite improved lung function and gas exchange as well as pulmonary ultrastructure after treatment, pulmonary SP messenger RNA expression and concentrations remained significantly affected, giving important insight into the time course following surfactant treatment in MAS.
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Affiliation(s)
- Anne Hilgendorff
- Department of Pediatrics and Neonatology, Justus-Liebig-University Giessen, Germany
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Pulkkinen V, Haataja R, Hannelius U, Helve O, Pitkänen OM, Karikoski R, Rehn M, Marttila R, Lindgren CM, Hästbacka J, Andersson S, Kere J, Hallman M, Laitinen T. G protein-coupled receptor for asthma susceptibility associates with respiratory distress syndrome. Ann Med 2006; 38:357-66. [PMID: 16938805 DOI: 10.1080/07853890600756453] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
BACKGROUND Respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD) have some common features with asthma. AIM To study whether G protein-coupled receptor for asthma susceptibility (GPRA) contributes to RDS or BPD. METHODS A haplotype association study was performed in a case-control setting of 521 Finnish infants (including 176 preterm neonates with RDS and 37 with BPD). Immunoreactivity of GPRA isoforms A and B was determined in pulmonary samples of fetuses, term infants and preterm infants with RDS or BPD. GPRA mRNA expression was determined by quantitative real-time polymerase chain reaction (PCR) in samples from nasal respiratory epithelium of adults, term infants and preterm infants. RESULTS In infants with RDS born at 32-35 weeks of gestation, GPRA haplotype H1 was significantly underrepresented in RDS, whereas haplotype H4/H5 was associated with an increased risk. As in asthma, GPRA B isoform was induced in bronchial smooth muscle cells in RDS and BPD. In nasal respiratory epithelium, relative GPRA mRNA expression was strong in adults, weak in preterm and slightly higher in term samples. CONCLUSIONS The results suggest that near-term RDS and asthma share the same susceptibility and protective GPRA haplotypes. Altered GPRA expression may play a role in the pathogenesis of RDS and BPD in preterm infants.
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Affiliation(s)
- Ville Pulkkinen
- Department of Medical Genetics, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland.
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22
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Turner BS, Bradshaw W, Brandon D. Neonatal lung remodeling: structural, inflammatory, and ventilator-induced injury. J Perinat Neonatal Nurs 2005; 19:362-76; quiz 377-8. [PMID: 16292137 DOI: 10.1097/00005237-200510000-00011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The developing lung is subject to events, both prenatal and postnatal, that alter the normal developmental process. The degree of insult or injury affects how the lung functions at birth and then responds to the insult throughout childhood. In this article, only 3 of the influences are examined: structural, inflammatory, and mechanical. It is recognized that there is a plethora of other factors that influence lung remodeling.
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Seppänen O, Glumoff V, Paananen R, Rounioja S, Hallman M. Transcription Factors NF-κB and C/EBPδ and IL-1-Induced Expression of Surfactant Protein A in Lung Explants during the Perinatal Period. Neonatology 2005; 87:152-9. [PMID: 15564781 DOI: 10.1159/000082312] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2004] [Accepted: 09/16/2004] [Indexed: 11/19/2022]
Abstract
Interleukin-1 (IL-1) increases the expression of surfactant protein A (SP-A) in rabbit, lamb and human fetal lung. The upregulation disappears towards term. Among the transcription factors, IL-1 activates nuclear factor kappaB (NF-kappaB) and CCAAT/enhancer-binding protein delta (C/EBPdelta). NF-kappaB presumably has a role in IL-1-induced upregulation of SP-A. Also, C/EBPdelta may regulate SP-A expression. The aim was to study the role of these transcription factors in the induced effect of IL-1 on SP-A expression. Explants from fetal and neonatal rabbit lung were cultured in vitro followed by studies using immunohistochemistry, electrophoretic mobility shift assay and Northern analysis. We found gestation-dependent changes in IL-1-induced immunoreactivities of NF-kappaB and C/EBPdelta in the nuclei of alveolar cells. This increase in nuclear transcription factors correlated with IL-1-induced SP-A expression levels. As studied in the explants from fetal and newborn lung, the SP-A mRNA expression additionally associated with C/EBPdelta mRNA and with the binding of nuclear extracts from the lung explants to the C/EBP consensus probe. On the basis of the present and previous studies, we propose that NF-kappaB and C/EBPdelta have potential mediator roles in IL-1-induced upregulation of SP-A in immature lung.
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Affiliation(s)
- Outi Seppänen
- Department of Pediatrics and Biocenter Oulu, University of Oulu, Oulu, Finland
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Merrill JD, Ballard RA, Cnaan A, Hibbs AM, Godinez RI, Godinez MH, Truog WE, Ballard PL. Dysfunction of pulmonary surfactant in chronically ventilated premature infants. Pediatr Res 2004; 56:918-26. [PMID: 15496605 DOI: 10.1203/01.pdr.0000145565.45490.d9] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Infants of <30 wk gestation often require respiratory support for several weeks and may develop bronchopulmonary dysplasia (BPD), which is associated with long-term pulmonary disability or death in severe cases. To examine the status of surfactant in infants at high risk for BPD, this prospective study analyzed 247 tracheal aspirate samples from 68 infants of 23-30 wk gestation who remained intubated for 7-84 d. Seventy-five percent of the infants had one or more surfactant samples with abnormal function (minimum surface tension 5.1-21.7 mN/m by pulsating bubble surfactometer), which were temporally associated with episodes of infection (p = 0.01) and respiratory deterioration (p = 0.005). Comparing normal and abnormal surfactant samples, there were no differences in amount of surfactant phospholipid, normalized to total protein that was recovered from tracheal aspirate, or in relative content of phosphatidylcholine and phosphatidylglycerol. Contents of surfactant proteins (SP) A, B, and C, measured in the surfactant pellet by immunoassay, were reduced by 50%, 80%, and 72%, respectively, in samples with abnormal surface tension (p < or = 0.001). On multivariable analysis of all samples, SP-B content (r = -0.58, p < 0.0001) and SP-C content (r = -0.32, p < 0.001) were correlated with surfactant function. We conclude that most premature infants requiring continued respiratory support after 7 d of age experience transient episodes of dysfunctional surfactant that are associated with a deficiency of SP-B and SP-C.
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Affiliation(s)
- Jeffrey D Merrill
- Neonatology, Department of Pediatrics, University of Pennsylvania School of Medicine, USA
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Prince LS, Okoh VO, Moninger TO, Matalon S. Lipopolysaccharide increases alveolar type II cell number in fetal mouse lungs through Toll-like receptor 4 and NF-κB. Am J Physiol Lung Cell Mol Physiol 2004; 287:L999-1006. [PMID: 15475494 DOI: 10.1152/ajplung.00111.2004] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chorioamnionitis is a major cause of preterm delivery. Infants exposed to inflammation in utero and then born preterm may have improved lung function in the immediate postnatal period. We developed a mouse model of chorioamnionitis to study the inflammatory signaling mechanisms that might influence fetal lung maturation. With this in vivo model, we found that Escherichia coli lipopolysaccharide (LPS) increased the number of alveolar type II cells in the fetal mouse lung. LPS also increased type II cell number in cultured fetal lung explants, suggesting that LPS could directly signal the fetal lung in the absence of maternal influences. Using immunostaining, we localized cells within the fetal mouse lung expressing the LPS receptor molecule Toll-like receptor 4 (TLR4). Similar to the signaling pathways in inflammatory cells, LPS activated NF-κB in fetal lung explants. Activation of the TLR4/NF-κB pathway appeared to be required, as LPS did not increase the number of type II cells in C.C3H- Tlr4 Lps-d mice, a congenic strain containing a loss of function mutation in tlr4. In addition, the sesquiterpene lactone parthenolide inhibited NF-κB activation following LPS exposure and blocked the LPS-induced increase in type II cells. On the basis of these data from our mouse model of chorioamnionitis, it appears that LPS specifically activated the TLR4/NF-κB pathway, leading to increased type II cell maturation. These data implicate an important signaling mechanism in chorioamnionitis and suggest the TLR4/NF-κB pathway can influence lung development.
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Affiliation(s)
- Lawrence S Prince
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama 35249, USA.
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Land SC, Darakhshan F. Thymulin evokes IL-6-C/EBPbeta regenerative repair and TNF-alpha silencing during endotoxin exposure in fetal lung explants. Am J Physiol Lung Cell Mol Physiol 2004; 286:L473-87. [PMID: 12639846 DOI: 10.1152/ajplung.00401.2002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chorioamnionitis is associated with increased risks of perinatal respiratory failure; however, components of the inflammatory acute-phase response are known to actively promote lung maturation. To manipulate this relationship, we examined the effect of the thymic immunomodulator thymulin on fetal lung mesenchyme-epithelial differentiation during exposure to Escherichia coli lipopolysaccharide (LPS). Gestation day 14 fetal rat lung explants were cultured for 96 h at fetal (23 mmHg) or ambient (142 mmHg) Po(2). Airway surface complexity (ASC, perimeter/ radical area(2)) was greater at fetal vs. ambient Po(2); however, exposure to 0.1-50 microg/ml LPS significantly raised ASC at 2 microg/ml in ambient Po(2) explants. LPS (50 microg/ml) depressed ASC in both conditions to untreated ambient Po(2) control values without changes in necrosis or apoptosis. To manipulate LPS-evoked TNF-alpha and IL-6 release, we exposed explants and A549 cells to combinations of 50 microg/ml LPS, 10 microM ZnCl(2), and 0.1-1,000 ng/ml thymulin at either Po(2). Thymulin+Zn(2+) suppressed and potentiated LPS-evoked TNF-alpha and IL-6 release, yielding an IC(50(TNF-alpha)) of 0.5 +/- 0.01 ng/ml and EC(50(IL-6)) of 1.4 +/- 0.3 ng/ml in A549 cells. This was accompanied by activation of the p38 MAPKMAPKAP-K2 pathway with sustained expression of TNF-alpha and IL-6 transcripts at ambient Po(2). LPS+thymulin+Zn(2+)-treated explants showed proliferation of CCAAT-enhancer binding protein-beta (C/EBPbeta) and fibroblast growth factor-9 immunoreactive mesenchyme, which was abolished by IL-6 antisense oligonucleotides. The posttranscriptional suppression of immunogenic TNF-alpha synthesis coupled with raised IL-6 and C/EBPbeta-dependent mesenchyme proliferation suggests a role for bioactive thymulin in regulating regenerative repair in the fetal lung.
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Affiliation(s)
- Stephen C Land
- Tayside Inst. of Child Health, Maternal and Child Health Sciences, Ninewells Hospital and Medical School, Univ. of Dundee, Dundee, DD1 9SY, UK.
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Mizgerd JP, Lupa MM, Hjoberg J, Vallone JC, Warren HB, Butler JP, Silverman ES. Roles for early response cytokines during Escherichia coli pneumonia revealed by mice with combined deficiencies of all signaling receptors for TNF and IL-1. Am J Physiol Lung Cell Mol Physiol 2004; 286:L1302-10. [PMID: 14966082 DOI: 10.1152/ajplung.00353.2003] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During infection, inflammation is essential for host defense, but it can injure tissues and compromise organ function. TNF-alpha and IL-1 (alpha and beta) are early response cytokines that facilitate inflammation. To determine the roles of these cytokines with overlapping functions, we generated mice deficient in all of the three receptors mediating their effects (TNFR1, TNFR2, and IL-1RI). During Escherichia coli pneumonia, receptor deficiency decreased neutrophil recruitment and edema accumulation to half of the levels observed in wild-type mice. Thus these receptors contributed to maximal responses, but substantial inflammation progressed independently of them. Receptor deficiency compromised antibacterial efficacy for some infectious doses. Decreased ventilation during E. coli pneumonia was not affected by receptor deficiency. However, the loss of lung compliance during pneumonia was substantially attenuated by receptor deficiency. Thus during E. coli pneumonia in mice, the lack of signaling from TNF-alpha and IL-1 decreases inflammation and preserves lung compliance.
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MESH Headings
- Animals
- Antigens, CD/genetics
- Antineoplastic Agents/immunology
- Antineoplastic Agents/pharmacology
- Escherichia coli Infections/immunology
- Escherichia coli Infections/metabolism
- Escherichia coli Infections/physiopathology
- Female
- Interleukin-1/immunology
- Interleukin-1/pharmacology
- Lung Compliance/immunology
- Male
- Mice
- Mice, Mutant Strains
- Pneumonia/immunology
- Pneumonia/metabolism
- Pneumonia, Bacterial/immunology
- Pneumonia, Bacterial/metabolism
- Pneumonia, Bacterial/physiopathology
- Receptors, Interleukin-1/genetics
- Receptors, Interleukin-1 Type I
- Receptors, Tumor Necrosis Factor/genetics
- Receptors, Tumor Necrosis Factor, Type I
- Receptors, Tumor Necrosis Factor, Type II
- Respiratory Mechanics/immunology
- Signal Transduction/immunology
- Tumor Necrosis Factor-alpha/immunology
- Tumor Necrosis Factor-alpha/pharmacology
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Affiliation(s)
- Joseph P Mizgerd
- Physiology Program, Harvard School of Public Health, Harvard Medical School, Boston, MA 02115, USA.
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28
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Vayrynen O, Glumoff V, Hallman M. Inflammatory and anti-inflammatory responsiveness of surfactant proteins in fetal and neonatal rabbit lung. Pediatr Res 2004; 55:55-60. [PMID: 14605255 DOI: 10.1203/01.pdr.0000100462.41671.c6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Spontaneous preterm birth due to intrauterine infection is associated with increased concentrations of cytokines in amniotic fluid and in the airways at birth. Intra-amniotic IL-1 induces fetal lung maturity, consistent with the decrease in the incidence of respiratory distress syndrome (RDS) in intrauterine inflammation. On the other hand, antenatal corticosteroid decreases the incidence of RDS in infants born prematurely. The aim of the present study was to investigate the interaction between IL-1 and glucocorticoid in the expression of the surfactant proteins SP-A, -B, and -C. Lung explants from rabbit fetuses at 22 (immature), 27 (transitional), and 30 (mature) d of gestation (term, 30-31 d) and on d 1 after term birth were cultured with dexamethasone (Dx), IL-1alpha, or vehicle in the presence or absence of actinomycin D. According to the present results, IL-1alpha and Dx additively increased the expression of SP-A and SP-B on d 22. Later in gestation, SP-B and SP-C were suppressed by IL-1, whereas glucocorticoid tended to increase the expression of SP-B and SP-C and prevented the IL-1-induced suppression of SP. IL-1alpha and steroid interactively increased the stability of SP mRNA compared with the single agonist, possibly explaining the additive effects on the SP mRNA levels. The present results reveal beneficial additive effects of glucocorticoid and cytokine on lung surfactant. They may explain some of the acute beneficial effects of glucocorticoid therapy in chorioamnionitis before premature birth and in inflammatory lung disease after birth.
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Affiliation(s)
- Outi Vayrynen
- Department of Pediatrics and Biocenter Oulu, University of Oulu, Kajaanintie 52, 90220 Oulu, Finland.
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29
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Hilgendorff A, Rawer D, Doerner M, Tutdibi E, Ebsen M, Schmidt R, Guenther A, Gortner L, Reiss I. Synthetic and natural surfactant differentially modulate inflammation after meconium aspiration. Intensive Care Med 2003; 29:2247-2254. [PMID: 12955179 DOI: 10.1007/s00134-003-1984-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2003] [Accepted: 07/28/2003] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Meconium aspiration syndrome remains a relevant cause of neonatal respiratory failure and is associated with severe pulmonary changes including surfactant inactivation and pronounced inflammatory changes. The present study investigated the effect of two different surfactant preparations-recombinant surfactant protein C surfactant (rSP-C Surf) and natural bovine surfactant-on pulmonary gas exchange and inflammatory response. DESIGN AND SUBJECTS Twenty-three newborn piglets were intubated, mechanically ventilated, received 5 ml/kg 20% sterile meconium for induction of lung injury, and were randomized thereafter for controls ( n=7), rSP-C Surf ( n=8), or natural surfactant ( n=8). Surfactants were given as an intratracheal bolus (75 mg/kg) and animals were further ventilated. MEASUREMENTS AND RESULTS Lung function variables, arterial blood gas samples and lung tissues were obtained. Histological evaluation was performed in right lung tissue using an established score. Cytokine mRNA expression (left lung tissue) was quantified using TaqMan real-time PCR (DeltaDeltaCT method, normalized to controls). In addition to significant improvement in gas exchange and lung function, histological evaluation showed significantly lower sum scores in the rSP-C Surf group than in controls). Cytokine mRNA expression of IL-1beta in whole lung tissue was significantly lower after administration of rSP-C Surf than in natural surfactant and controls whereas IL-10 mRNA expression was significantly induced in both surfactant groups. CONCLUSIONS Surfactant administration improved both gas exchange and pulmonary inflammatory cytokine transcription. Mechanisms underlying the differential inflammatory response in both surfactant preparations need to be further addressed.
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Affiliation(s)
- Anne Hilgendorff
- Department of Pediatrics and Neonatology, Justus Liebig University of Giessen, 35392, Giessen, Germany.
| | - Daniel Rawer
- Department of Pediatrics and Neonatology, Justus Liebig University of Giessen, 35392, Giessen, Germany
| | - Martin Doerner
- Department of Pediatrics and Neonatology, Justus Liebig University of Giessen, 35392, Giessen, Germany
| | - Erol Tutdibi
- Department of Pediatrics and Neonatology, Justus Liebig University of Giessen, 35392, Giessen, Germany
| | - Michael Ebsen
- Department of Pathology, University of Bochum, Bochum, Germany
| | - Reinhold Schmidt
- Department of Internal Medicine, Justus Liebig University of Giessen, 35392, Giessen, Germany
| | - Andreas Guenther
- Department of Internal Medicine, Justus Liebig University of Giessen, 35392, Giessen, Germany
| | - Ludwig Gortner
- Department of Pediatrics and Neonatology, Justus Liebig University of Giessen, 35392, Giessen, Germany
| | - Irwin Reiss
- Department of Pediatrics and Neonatology, Justus Liebig University of Giessen, 35392, Giessen, Germany
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30
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Aikio O, Saarela T, Pokela ML, Hallman M. Nitric oxide treatment and acute pulmonary inflammatory response in very premature infants with intractable respiratory failure shortly after birth. Acta Paediatr 2003; 92:65-9. [PMID: 12650302 DOI: 10.1111/j.1651-2227.2003.tb00471.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM Premature infants with respiratory failure and early-onset pneumonia have low inducible nitric oxide synthase (NOS2) and no evidence of nitric oxide (NO) toxicity. However, inhalation of NO may not be indicated in sepsis because excessive NO generation has been reported. This prospective study was designed to test the hypothesis that inhaled NO is effective in a select group of small premature infants and that the responsiveness to NO is associated with low NOS2 enzyme. METHODS 246 very low birthweight infants (birthweight <1500 g, VLBW) were screened for severe, intractable respiratory failure (oxygenation index >40, arterial-alveolar ratio for oxygen tension <0.10) that does not respond to two doses of surfactant within 5 h from birth. Infants with severe cardiac failure or a bleeding disorder were excluded. Five of the nine eligible cases received inhaled NO. They all had prolonged rupture of foetal membranes, early-onset pneumonia and persistent pulmonary hypertension. RESULTS All five responded strikingly, survived and appeared normal in follow-up. Airway specimens during the first day of life revealed very low NOS2, interleukin-1beta and surfactant protein A, compared with VLBW infants who had no acute infection despite histological chorioamnionitis. In early-onset pneumonia, NOS2 and other inflammatory mediators increased first during the recovery 1-2 d after birth. CONCLUSION VLBW infants with progressive respiratory failure and infection at birth have deficient pulmonary NOS2 and cytokine response. After surfactant therapy, these infants responded strikingly to inhaled NO. An acute pulmonary inflammatory response may contribute to respiratory adaptation in early-onset pneumonia.
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Affiliation(s)
- O Aikio
- Department of Paediatrics, University of Oulu, Oulu, Finland
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31
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Siflinger-Birnboim A, Johnson A. Protein kinase C modulates pulmonary endothelial permeability: a paradigm for acute lung injury. Am J Physiol Lung Cell Mol Physiol 2003; 284:L435-51. [PMID: 12573983 DOI: 10.1152/ajplung.00106.2002] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The intracellular serine/threonine kinase protein kinase C (PKC) has an important role in the genesis of pulmonary edema. This review discusses the PKC-mediated mechanisms that participate in the pulmonary endothelial response to agents involved in lung injury characteristic of the respiratory distress syndrome. Thus the paradigms of PKC-induced lung injury are discussed within the context of pulmonary transvascular fluid exchange. We focus on the signal transduction pathways that are modulated by PKC and their effect on lung endothelial permeability. Specifically, alpha-thrombin, tumor necrosis factor (TNF)-alpha, and reactive oxygen species are discussed because of their well-established roles in both human and experimental lung injury. We conclude that PKC, most likely PKC-alpha, is a primary supporter for lung endothelial injury in response to alpha-thrombin, TNF-alpha, and reactive oxygen species.
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Affiliation(s)
- Alma Siflinger-Birnboim
- Research Service, Stratton Veterans Affairs Medical Center; and the Center for Cardiovascular Science, The Albany Medical College, Albany, New York 12208, USA
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32
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Abstract
Neonatal lung diseases may have a genetic background. The available studies mainly concentrate on surfactant proteins (SP-A, SP-B) and respiratory distress syndrome. Specific alleles of the SP-A and SP-B genes associate interactively with susceptibility to respiratory distress syndrome. This genetic impact on the condition is influenced by environmental, acquired and inherited factors. Other alleles and genotypes of SP-A and SP-D associate with severe respiratory infections in early infancy. Rare mutations causing an absence of the SP-B protein result in progressive respiratory failure. Dominant mutations of SP-C associate with chronic lung disease, with variable manifestations. The first steps towards unraveling the genetic network influencing the susceptibility to neonatal lung diseases are now being taken. Genes encoding multifunctional proteins in the distal lung are prime candidates for causing susceptibility to neonatal lung disease, including bronchopulmonary dysplasia.
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Affiliation(s)
- Mikko Hallman
- Department of Pediatrics, University of Oulu, Kajaanintie 52A PL 5000, 90014, Oulu, Finland.
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Fan X, Subramaniam R, Weiss MF, Monnier VM. Methylglyoxal-bovine serum albumin stimulates tumor necrosis factor alpha secretion in RAW 264.7 cells through activation of mitogen-activating protein kinase, nuclear factor kappaB and intracellular reactive oxygen species formation. Arch Biochem Biophys 2003; 409:274-86. [PMID: 12504894 DOI: 10.1016/s0003-9861(02)00599-4] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Accumulating evidence suggests that the pathophysiology of diabetes is analogous to chronic inflammatory states. Circulating levels of inflammatory cytokines such as IL-6 and tumor necrosis factor alpha (TNFalpha) are increased in both type 1 and type 2 diabetes. TNFalpha plays an important role in the pathogenesis of insulin resistance in type 2 diabetes. However, the reason for this increase remains unclear. Levels of the dicarbonyl methylglyoxal (MGO) are elevated in diabetic plasma and MGO-modified bovine serum albumin (MGO-BSA) can trigger cellular uptake of TNF. Therefore we tested the hypothesis that MGO-modified proteins may cause TNFalpha secretion in macrophage-like RAW 264.7 cells. Treatment of cells with MGO-BSA induced TNFalpha release in a dose-dependent manner. MGO-modified ribonuclease A and chicken egg ovalbumin had similar effects. Cotreatment of cells with antioxidant reagent N-acetylcysteine (NAC) inhibited MGO-BSA-induced TNFalpha secretion. MGO-BSA stimulated the simultaneous activation of p44/42 and p38 mitogen-activated protein kinase. PD98059, a selective MEK inhibitor, inhibited MGO-BSA-induced TNFalpha release as well as ERK phosphorylation. Pretreatment of cells with NAC also resulted in inhibition of MGO-BSA-induced ERK phosphorylation. MGO-BSA induced dose-dependent NFkappaB activation as shown by electrophoresis mobility shift assay. The MGO-BSA-induced NFkappaB activation was prevented in the presence of PD98059, NAC, and parthenolide, a selective inhibitor of NFkappaB. Furthermore, the NFkappaB inhibitor parthenolide suppressed MGO-BSA-induced TNFalpha secretion. Confocal microscopy using dichlorofluorescein to demonstrate intracellular reactive oxygen species (ROS) showed that MGO-BSA produced more ROS compared with native BSA. MGO-BSA could also stimulate protein kinase C (PKC) translocation to the cell membrane, considered a key signaling pathway in diabetes. However, there was no evidence that PKC was involved in TNFalpha release based on inhibition by calphostin C and staurosporine. Our findings suggest that the presence of chronically elevated levels of MGO-modified bovine serum albumin may contribute to elevated levels of TNFalpha in diabetes.
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Affiliation(s)
- X Fan
- Institute of Pathology, Case Western Reserve University, Clevelard, OH 44106, USA
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