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Baumann P, Cannizzaro V. Lung function assessment in critically ill children: craving for standardisation. CURRENT OPINION IN PHYSIOLOGY 2021. [DOI: 10.1016/j.cophys.2021.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Baumann P, Wiegert S, Greco F, Ersch J, Cannizzaro V. Strain-specific differences in lung tissue viscoelasticity of mechanically ventilated infant Sprague-Dawley and Wistar rats. Am J Physiol Lung Cell Mol Physiol 2020; 320:L220-L231. [PMID: 33207919 DOI: 10.1152/ajplung.00100.2020] [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: 01/13/2023] Open
Abstract
Rats are often used in ventilator-induced lung injury (VILI) models. However, strain-specific susceptibility for VILI has not been elucidated yet. The aim of this study was to demonstrate strain-specific differences in VILI in infant Sprague-Dawley and Wistar rats. VILI was compared in 2-wk-old pups after 8 h of protective or injurious ventilation. Pups were ventilated with tidal volumes (VT) of ∼7 mL/kg and positive end-expiratory pressures (PEEP) of 6 cmH2O (VT7 PEEP6) or with VT of ∼21 mL/kg and PEEP 2 cmH2O (VT21 PEEP2). Interleukin-6, macrophage inflammatory protein-2 (MIP-2), inflammatory cells, and albumin in bronchoalveolar lavage fluid (BALF); histology; and low-frequency forced oscillation technique (LFOT) and pressure-volume (PV) maneuvers were assessed. Alveolar macrophages, neutrophils, and MIP-2 derived from BALF revealed more pronounced VILI after VT21 PEEP2 in both strains. LFOT and PV analyses demonstrated rat strain-specific differences both at baseline and particularly in response to VT21 PEEP2 ventilation. Sprague-Dawley rats showed higher airway and tissue resistance and elastance values with no difference in hysteresivity between ventilation strategies. Wister rats challenged by VT21 PEEP2 experienced significantly more energy dissipation when compared with VT7 PEEP6 ventilation. In conclusion, both rat strains are useful for VILI models. The degree of VILI severity depends on ventilation strategy and selected strain. However, fundamental and time-dependent differences in respiratory system mechanics exist and reflect different lung tissue viscoelasticity. Hence, strain-specific characteristics of the respiratory system need to be considered when planning and interpreting VILI studies with infant rats.
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Affiliation(s)
- Philipp Baumann
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Susanne Wiegert
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Francesco Greco
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Joerg Ersch
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Vincenzo Cannizzaro
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,Department of Neonatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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Amadi PU, Agomuo EN, Adumekwe CW. Modulatory properties of cardiac and quercetin glycosides from Dacryodes edulis seeds during L-NAME-induced vascular perturbation. J Basic Clin Physiol Pharmacol 2020; 31:/j/jbcpp.ahead-of-print/jbcpp-2019-0116/jbcpp-2019-0116.xml. [PMID: 32653874 DOI: 10.1515/jbcpp-2019-0116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 03/06/2020] [Indexed: 02/06/2023]
Abstract
Background Numerous food wastes have been identified to possess potent bioactive compounds used for the treatment of several diseases. Therefore this study evaluated the potentials of cardiac and quercetin glycosides extracted from Dacryodes edulis seeds to reverse vascular and endothelial damage (VAED). Methods The glycoside composition of the seeds was extracted using standard methods and characterized by gas chromatography. We then recruited rats with L-NAME-induced VAED based on confirmatory biomarkers cardiac troponin (CnT), cellular adhesion molecule (VCAM-1), lipoprotein associated phospholipase A2 (Lp-PLA2), RAAS, VWF, endothelin, eNOx, and homocysteine. Only rats that showed total alterations of all biomarkers were recruited into the respective experimental groups and treated with either metaprolol succinate (met.su) + losartan or glycoside extracts of D. edulis seeds (NPSG). Results Chromatographic isolation of glycosides in the seed showed predominance of artemetin (1.59 mg/100 g), amygdalin (3.68 mg/100 g), digitoxin (19.21 mg/100 g), digoxin (27.23 mg/100 g), avicularin (133.59 mg/100 g), and hyperoside (481.76 mg/100 g). We observed decreased water intake and higher heart beats under vascular damage as the experiment progressed up to the fourth week. The met.su + losartan and H.D NPSG proved effective in restoring troponin, but both doses of NPSG normalized the VCAM-1 and RAAS activities excluding aldosterone and Lp-PLA2. Among the endothelial dysfunction biomarkers, H.D NPSG produced equivalent effects to met.su + losartan towards restoring the eNOx and VWF activities, but showed higher potency in normalizing the endothelin and Hcy levels. Conclusions We thus propose that the synergistic effect of the isolated glycosides from D. edulis shown in our study proved potent enough at high doses in treatment of vascular and endothelial dysfunction.
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Affiliation(s)
- Peter Uchenna Amadi
- Department of Biochemistry, University of Port Harcourt, Choba, Rivers State, Nigeria.,Department of Biochemistry, Imo State, University, Owerri, Imo State, Nigeria
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Wiegert S, Greco F, Baumann P, Wellmann S, Grest P, Hetzel U, Cannizzaro V. Impact of high tidal volume ventilation on surfactant metabolism and lung injury in infant rats. Am J Physiol Lung Cell Mol Physiol 2020; 319:L562-L575. [PMID: 32579393 DOI: 10.1152/ajplung.00043.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The poorly understood tolerance toward high tidal volume (VT) ventilation observed in critically ill children and age-equivalent animal models may be explained by surfactant homeostasis. The aim of our prospective animal study was to test whether high VT with adequate positive end-expiratory pressure (PEEP) is associated with surfactant de novo synthesis and secretion, leading to improved lung function, and whether extreme mechanical ventilation affects intracellular lamellar body formation and exocytosis. Rats (14 days old) were allocated to five groups: nonventilated controls, PEEP 5 cmH2O with VT of 8, 16, and 24 mL/kg, and PEEP 1 cmH2O with VT 24 mL/kg. Following 6 h of ventilation, lung function, surfactant proteins and phospholipids, and lamellar bodies were assessed by forced oscillation technique, quantitative real-time polymerase chain reaction, mass spectrometry, immunohistochemistry, and transmission electron microscopy. High VT (24 mL/kg) with PEEP of 5 cmH2O improved respiratory system mechanics and was not associated with lung injury, elevated surfactant protein expression, or surfactant phospholipid content. Extreme ventilation with VT 24 mL/kg and PEEP 1 cmH2O produced a mild inflammatory response and correlated with higher surfactant phospholipid concentrations in bronchoalveolar lavage fluid without affecting lamellar body count and morphology. Elevated phospholipid concentrations in the potentially most injurious strategy (VT 24 mL/kg, PEEP 1 cmH2O) need further evaluation and might reflect accumulation of biophysically inactive small aggregates. In conclusion, our data confirm the resilience of infant rats toward high VT-induced lung injury and challenge the relevance of surfactant synthesis, storage, and secretion as protective factors.
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Affiliation(s)
- Susanne Wiegert
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Centre, University Children's Hospital Zurich, Zurich, Switzerland.,Zurich Centre for Integrative Human Physiology, Zurich, Switzerland
| | - Francesco Greco
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Centre, University Children's Hospital Zurich, Zurich, Switzerland.,Zurich Centre for Integrative Human Physiology, Zurich, Switzerland
| | - Philipp Baumann
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Centre, University Children's Hospital Zurich, Zurich, Switzerland
| | - Sven Wellmann
- Zurich Centre for Integrative Human Physiology, Zurich, Switzerland.,Department of Neonatology, University Children's Hospital Basel, Basel, Switzerland.,Department of Neonatology, University Children's Hospital Regensburg, University of Regensburg, Regensburg, Germany
| | - Paula Grest
- Vetsuisse Faculty, Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, University of Zurich, Zurich, Switzerland
| | - Udo Hetzel
- Vetsuisse Faculty, Laboratory for Animal Model Pathology, Institute of Veterinary Pathology, University of Zurich, Zurich, Switzerland
| | - Vincenzo Cannizzaro
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Centre, University Children's Hospital Zurich, Zurich, Switzerland.,Zurich Centre for Integrative Human Physiology, Zurich, Switzerland
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Wardoyo AYP, Juswono UP, Noor JAE. Varied dose exposures to ultrafine particles in the motorcycle smoke cause kidney cell damages in male mice. Toxicol Rep 2018; 5:383-389. [PMID: 29854608 PMCID: PMC5977376 DOI: 10.1016/j.toxrep.2018.02.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 02/27/2018] [Accepted: 02/27/2018] [Indexed: 01/06/2023] Open
Abstract
Exposure to ultrafine particles has significant effect on kidney cell deformation. The exposure results in alterations in glomerular and tubular epithelial cells. Ultrafine particle concentration determines kidney cell deformation.
Ultrafine particles (UFPs) are one of motorcycle exhaust emissions which can penetrate the lung alveoli and deposit in the kidney. This study was aimed to investigate mice kidney cell physical damage (deformation) due to motorcycle exhaust emission exposures. The motorcycle exhaust emissions were sucked from the muffler with the rate of 33 cm3/s and passed through an ultrafine particle filter system before introduced into the mice exposure chamber. The dose concentration of the exhaust emissions was varied by setting the injected time of the 20s, 40s, 60s, 80s, and 100s. The mice were exposed to the smoke in the chamber for 100 s twice a day. The impact of the ultrafine particles on the kidney was observed by identifying the histological image of the kidney cell deformation using a microscope. The exposure was conducted for 10 days. The kidney observations were carried out on day 11. The results showed that there was a significant linear correlation between the total concentration of ultrafine particles deposited in the kidneys and the physical damage percentages. The increased concentrations of ultrafine particles caused larger cell deformation to the kidneys.
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Affiliation(s)
- Arinto Y P Wardoyo
- Department of Physics, Brawijaya University, Malang Indonesia Jl. Veteran, Malang, East Java, 65145, Indonesia
| | - Unggul P Juswono
- Department of Physics, Brawijaya University, Malang Indonesia Jl. Veteran, Malang, East Java, 65145, Indonesia
| | - Johan A E Noor
- Department of Physics, Brawijaya University, Malang Indonesia Jl. Veteran, Malang, East Java, 65145, Indonesia
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Cagle LA, Franzi LM, Linderholm AL, Last JA, Adams JY, Harper RW, Kenyon NJ. Effects of positive end-expiratory pressure and recruitment maneuvers in a ventilator-induced injury mouse model. PLoS One 2017; 12:e0187419. [PMID: 29112971 PMCID: PMC5675408 DOI: 10.1371/journal.pone.0187419] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 10/19/2017] [Indexed: 12/26/2022] Open
Abstract
Background Positive-pressure mechanical ventilation is an essential therapeutic intervention, yet it causes the clinical syndrome known as ventilator-induced lung injury. Various lung protective mechanical ventilation strategies have attempted to reduce or prevent ventilator-induced lung injury but few modalities have proven effective. A model that isolates the contribution of mechanical ventilation on the development of acute lung injury is needed to better understand biologic mechanisms that lead to ventilator-induced lung injury. Objectives To evaluate the effects of positive end-expiratory pressure and recruitment maneuvers in reducing lung injury in a ventilator-induced lung injury murine model in short- and longer-term ventilation. Methods 5–12 week-old female BALB/c mice (n = 85) were anesthetized, placed on mechanical ventilation for either 2 hrs or 4 hrs with either low tidal volume (8 ml/kg) or high tidal volume (15 ml/kg) with or without positive end-expiratory pressure and recruitment maneuvers. Results Alteration of the alveolar-capillary barrier was noted at 2 hrs of high tidal volume ventilation. Standardized histology scores, influx of bronchoalveolar lavage albumin, proinflammatory cytokines, and absolute neutrophils were significantly higher in the high-tidal volume ventilation group at 4 hours of ventilation. Application of positive end-expiratory pressure resulted in significantly decreased standardized histology scores and bronchoalveolar absolute neutrophil counts at low- and high-tidal volume ventilation, respectively. Recruitment maneuvers were essential to maintain pulmonary compliance at both 2 and 4 hrs of ventilation. Conclusions Signs of ventilator-induced lung injury are evident soon after high tidal volume ventilation (as early as 2 hours) and lung injury worsens with longer-term ventilation (4 hrs). Application of positive end-expiratory pressure and recruitment maneuvers are protective against worsening VILI across all time points. Dynamic compliance can be used guide the frequency of recruitment maneuvers to help ameloriate ventilator-induced lung injury.
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Affiliation(s)
- Laura A. Cagle
- Center for Comparative Respiratory Biology and Medicine, University of California, Davis, Davis, CA, United States of America
- * E-mail:
| | - Lisa M. Franzi
- Center for Comparative Respiratory Biology and Medicine, University of California, Davis, Davis, CA, United States of America
| | - Angela L. Linderholm
- Center for Comparative Respiratory Biology and Medicine, University of California, Davis, Davis, CA, United States of America
| | - Jerold A. Last
- Center for Comparative Respiratory Biology and Medicine, University of California, Davis, Davis, CA, United States of America
| | - Jason Y. Adams
- Division of Pulmonary, Critical Care, and Sleep Medicine, School of Medicine, University of California, Davis, Davis, CA, United States of America
| | - Richart W. Harper
- Center for Comparative Respiratory Biology and Medicine, University of California, Davis, Davis, CA, United States of America
- Division of Pulmonary, Critical Care, and Sleep Medicine, School of Medicine, University of California, Davis, Davis, CA, United States of America
| | - Nicholas J. Kenyon
- Center for Comparative Respiratory Biology and Medicine, University of California, Davis, Davis, CA, United States of America
- Division of Pulmonary, Critical Care, and Sleep Medicine, School of Medicine, University of California, Davis, Davis, CA, United States of America
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Hillman GG, Singh-Gupta V, Lonardo F, Hoogstra DJ, Abernathy LM, Yunker CK, Rothstein SE, Rakowski J, Sarkar FH, Gadgeel S, Konski AA, Joiner MC. Radioprotection of lung tissue by soy isoflavones. J Thorac Oncol 2013; 8:1356-64. [PMID: 24077456 PMCID: PMC3800250 DOI: 10.1097/jto.0b013e3182a4713e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
INTRODUCTION Radiation-induced pneumonitis and fibrosis have restricted radiotherapy for lung cancer. In a preclinical lung tumor model, soy isoflavones showed the potential to enhance radiation damage in tumor nodules and simultaneously protect normal lung from radiation injury. We have further dissected the role of soy isoflavones in the radioprotection of lung tissue. METHODS Naive Balb/c mice were treated with oral soy isoflavones for 3 days before and up to 4 months after radiation. Radiation was administered to the left lung at 12 Gy. Mice were monitored for toxicity and breathing rates at 2, 3, and 4 months after radiation. Lung tissues were processed for histology for in situ evaluation of response. RESULTS Radiation caused damage to normal hair follicles, leading to hair loss in the irradiated left thoracic area. Supplementation with soy isoflavones protected mice against radiation-induced skin injury and hair loss. Lung irradiation also caused an increase in mouse breathing rate that was more pronounced by 4 months after radiation, probably because of the late effects of radiation-induced injury to normal lung tissue. However, this effect was mitigated by soy isoflavones. Histological examination of irradiated lungs revealed a chronic inflammatory infiltration involving alveoli and bronchioles and a progressive increase in fibrosis. These adverse effects of radiation were alleviated by soy isoflavones. CONCLUSION Soy isoflavones given pre- and postradiation protected the lungs against adverse effects of radiation including skin injury, hair loss, increased breathing rates, inflammation, pneumonitis and fibrosis, providing evidence for a radioprotective effect of soy.
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Affiliation(s)
- Gilda G. Hillman
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Vinita Singh-Gupta
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Fulvio Lonardo
- Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - David J. Hoogstra
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Lisa M. Abernathy
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Christopher K. Yunker
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Shoshana E. Rothstein
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Joseph Rakowski
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Fazlul H. Sarkar
- Department of Pathology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Shirish Gadgeel
- Department of Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Andre A. Konski
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Michael C. Joiner
- Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA
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Reiss LK, Kowallik A, Uhlig S. Recurrent recruitment manoeuvres improve lung mechanics and minimize lung injury during mechanical ventilation of healthy mice. PLoS One 2011; 6:e24527. [PMID: 21935418 PMCID: PMC3174196 DOI: 10.1371/journal.pone.0024527] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 08/12/2011] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Mechanical ventilation (MV) of mice is increasingly required in experimental studies, but the conditions that allow stable ventilation of mice over several hours have not yet been fully defined. In addition, most previous studies documented vital parameters and lung mechanics only incompletely. The aim of the present study was to establish experimental conditions that keep these parameters within their physiological range over a period of 6 h. For this purpose, we also examined the effects of frequent short recruitment manoeuvres (RM) in healthy mice. METHODS Mice were ventilated at low tidal volume V(T) = 8 mL/kg or high tidal volume V(T) = 16 mL/kg and a positive end-expiratory pressure (PEEP) of 2 or 6 cm H(2)O. RM were performed every 5 min, 60 min or not at all. Lung mechanics were followed by the forced oscillation technique. Blood pressure (BP), electrocardiogram (ECG), heart frequency (HF), oxygen saturation and body temperature were monitored. Blood gases, neutrophil-recruitment, microvascular permeability and pro-inflammatory cytokines in bronchoalveolar lavage (BAL) and blood serum as well as histopathology of the lung were examined. RESULTS MV with repetitive RM every 5 min resulted in stable respiratory mechanics. Ventilation without RM worsened lung mechanics due to alveolar collapse, leading to impaired gas exchange. HF and BP were affected by anaesthesia, but not by ventilation. Microvascular permeability was highest in atelectatic lungs, whereas neutrophil-recruitment and structural changes were strongest in lungs ventilated with high tidal volume. The cytokines IL-6 and KC, but neither TNF nor IP-10, were elevated in the BAL and serum of all ventilated mice and were reduced by recurrent RM. Lung mechanics, oxygenation and pulmonary inflammation were improved by increased PEEP. CONCLUSIONS Recurrent RM maintain lung mechanics in their physiological range during low tidal volume ventilation of healthy mice by preventing atelectasis and reduce the development of pulmonary inflammation.
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Affiliation(s)
- Lucy Kathleen Reiss
- Institute of Pharmacology and Toxicology, Medical Faculty of RWTH Aachen University, Aachen, Germany.
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Cannizzaro V, Hantos Z, Sly PD, Zosky GR. Linking lung function and inflammatory responses in ventilator-induced lung injury. Am J Physiol Lung Cell Mol Physiol 2010; 300:L112-20. [PMID: 20952494 DOI: 10.1152/ajplung.00158.2010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Despite decades of research, the mechanisms of ventilator-induced lung injury are poorly understood. We used strain-dependent responses to mechanical ventilation in mice to identify associations between mechanical and inflammatory responses in the lung. BALB/c, C57BL/6, and 129/Sv mice were ventilated using a protective [low tidal volume and moderate positive end-expiratory pressure (PEEP) and recruitment maneuvers] or injurious (high tidal volume and zero PEEP) ventilation strategy. Lung mechanics and lung volume were monitored using the forced oscillation technique and plethysmography, respectively. Inflammation was assessed by measuring numbers of inflammatory cells, cytokine (IL-6, IL-1β, and TNF-α) levels, and protein content of the BAL. Principal components factor analysis was used to identify independent associations between lung function and inflammation. Mechanical and inflammatory responses in the lung were dependent on ventilation strategy and mouse strain. Three factors were identified linking 1) pulmonary edema, protein leak, and macrophages, 2) atelectasis, IL-6, and TNF-α, and 3) IL-1β and neutrophils, which were independent of responses in lung mechanics. This approach has allowed us to identify specific inflammatory responses that are independently associated with overstretch of the lung parenchyma and loss of lung volume. These data provide critical insight into the mechanical responses in the lung that drive local inflammation in ventilator-induced lung injury and the basis for future mechanistic studies in this field.
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Affiliation(s)
- Vincenzo Cannizzaro
- Department of Intensive Care and Neonatology, University Children’s Hospital, Zurich, Switzerland
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Ma B, Bates JHT. Modeling the complex dynamics of derecruitment in the lung. Ann Biomed Eng 2010; 38:3466-77. [PMID: 20552275 DOI: 10.1007/s10439-010-0095-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 06/03/2010] [Indexed: 11/24/2022]
Abstract
Recruitment maneuvers using deep inflations (DI) have long been used clinically with the objective of recruiting collapsed regions of the lung. Considerable uncertainty continues to exist, however, as to how best to employ recruitment maneuvers or even if they should be used routinely at all for patients receiving mechanical ventilation. Much of this uncertainty may arise from a lack of understanding about the dynamic nature of recruitment and derecruitment. To shed some light on this complex issue, we developed a time-dependent computational model of recruitment and derecruitment in the lung based on a symmetrically bifurcating airway tree in which each branch has a critical closing and opening pressure as well as pressure-dependent opening and closing speeds. Starting from the fully open state, the model underwent regular ventilation for 8 min followed by a series of identical DIs separated by 5 min of identical regular ventilation. We found that the geographical nature and extent of derecruitment before and 5 min after each DI were not always the same, demonstrating that the model exhibits multiple stable states. We conclude that the effectiveness of a recruitment maneuver is not only simply a function of the duration and magnitude of a DI, but may also have an unpredictable component arising from the distributed bi-stable nature of the derecruitment process itself.
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Affiliation(s)
- Baoshun Ma
- Vermont Lung Center, Department of Medicine, University of Vermont College of Medicine, 149 Beaumont Ave., HSRF 228, Burlington, VT 05405, USA
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Hauber HP, Karp D, Goldmann T, Vollmer E, Zabel P. Effect of low tidal volume ventilation on lung function and inflammation in mice. BMC Pulm Med 2010; 10:21. [PMID: 20409304 PMCID: PMC2864238 DOI: 10.1186/1471-2466-10-21] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Accepted: 04/21/2010] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND A large number of studies have investigated the effects of high tidal volume ventilation in mouse models. In contrast data on very short term effects of low tidal volume ventilation are sparse. Therefore we investigated the functional and structural effects of low tidal volume ventilation in mice. METHODS 38 Male C57/Bl6 mice were ventilated with different tidal volumes (Vt 5, 7, and 10 ml/kg) without or with application of PEEP (2 cm H2O). Four spontaneously breathing animals served as controls. Oxygen saturation and pulse rate were monitored. Lung function was measured every 5 min for at least 30 min. Afterwards lungs were removed and histological sections were stained for measurement of infiltration with polymorphonuclear leukocytes (PMN). Moreover, mRNA expression of macrophage inflammatory protein (MIP)-2 and tumor necrosis factor (TNF)alpha in the lungs was quantified using real time PCR. RESULTS Oxygen saturation did not change significantly over time of ventilation in all groups (P > 0.05). Pulse rate dropped in all groups without PEEP during mechanical ventilation. In contrast, in the groups with PEEP pulse rate increased over time. These effects were not statistically significant (P > 0.05). Tissue damping (G) and tissue elastance (H) were significantly increased in all groups after 30 min of ventilation (P < 0.05). Only the group with a Vt of 10 ml/kg and PEEP did not show a significant increase in H (P > 0.05). Mechanical ventilation significantly increased infiltration of the lungs with PMN (P < 0.05). Expression of MIP-2 was significantly induced by mechanical ventilation in all groups (P < 0.05). MIP-2 mRNA expression was lowest in the group with a Vt of 10 ml/kg + PEEP. CONCLUSIONS Our data show that very short term mechanical ventilation with lower tidal volumes than 10 ml/kg did not reduce inflammation additionally. Formation of atelectasis and inadequate oxygenation with very low tidal volumes may be important factors. Application of PEEP attenuated inflammation.
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Affiliation(s)
- Hans P Hauber
- Division of Pathophysiology of Inflammation, Research Center Borstel, Borstel, Germany.
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