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Adverse Mechanical Ventilation and Pneumococcal Pneumonia Induce Immune and Mitochondrial Dysfunctions Mitigated by Mesenchymal Stem Cells in Rabbits. Anesthesiology 2021; 136:293-313. [PMID: 34965287 DOI: 10.1097/aln.0000000000004083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Mechanical ventilation for pneumonia may contribute to lung injury due to factors that include mitochondrial dysfunction, and mesenchymal stem cells may attenuate injury. This study hypothesized that mechanical ventilation induces immune and mitochondrial dysfunction, with or without pneumococcal pneumonia, that could be mitigated by mesenchymal stem cells alone or combined with antibiotics. METHODS Male rabbits underwent protective mechanical ventilation (8 ml/kg tidal volume, 5 cm H2O end-expiratory pressure) or adverse mechanical ventilation (20 ml/kg tidal-volume, zero end-expiratory pressure) or were allowed to breathe spontaneously. The same settings were then repeated during pneumococcal pneumonia. Finally, infected animals during adverse mechanical ventilation received human umbilical cord-derived mesenchymal stem cells (3 × 106/kg, intravenous) and/or ceftaroline (20 mg/kg, intramuscular) or sodium chloride, 4 h after pneumococcal challenge. Twenty-four-hour survival (primary outcome), lung injury, bacterial burden, immune and mitochondrial dysfunction, and lung transcriptomes (secondary outcomes) were assessed. RESULTS High-pressure adverse mechanical ventilation reduced the survival of infected animals (0%; 0 of 7) compared with spontaneous breathing (100%; 7 of 7) and protective mechanical ventilation (86%; 6 of 7; both P < 0.001), with higher lung pathology scores (median [interquartile ranges], 5.5 [4.5 to 7.0] vs. 12.6 [12.0 to 14.0]; P = 0.046), interleukin-8 lung concentrations (106 [54 to 316] vs. 804 [753 to 868] pg/g of lung; P = 0.012), and alveolar mitochondrial DNA release (0.33 [0.28 to 0.36] vs. 0.98 [0.76 to 1.21] ng/μl; P < 0.001) compared with infected spontaneously breathing animals. Survival (0%; 0 of 7; control group) was improved by mesenchymal stem cells (57%; 4 of 7; P = 0.001) or ceftaroline alone (57%; 4 of 7; P < 0.001) and improved even more with a combination treatment (86%; 6 of 7; P < 0.001). Mesenchymal stem cells reduced lung pathology score (8.5 [7.0 to 10.5] vs. 12.6 [12.0 to 14.0]; P = 0.043) and alveolar mitochondrial DNA release (0.39 (0.34 to 0.65) vs. 0.98 (0.76 to 1.21) ng/μl; P = 0.025). Mesenchymal stem cells combined with ceftaroline reduced interleukin-8 lung concentrations (665 [595 to 795] vs. 804 [753 to 868] pg/g of lung; P = 0.007) compared to ceftaroline alone. CONCLUSIONS In this preclinical study, mesenchymal stem cells improved the outcome of rabbits with pneumonia and high-pressure mechanical ventilation by correcting immune and mitochondrial dysfunction and when combined with the antibiotic ceftaroline was synergistic in mitigating lung inflammation. EDITOR’S PERSPECTIVE
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Abstract
Streptococcus pneumoniae remains the most common bacterial pathogen causing lower respiratory tract infections and is a leading cause of morbidity and mortality worldwide, especially in children and the elderly. Another important aspect related to pneumococcal infections is the persistent rate of penicillin and macrolide resistance. Therefore, animal models have been developed to better understand the pathogenesis of pneumococcal disease and test new therapeutic agents and vaccines. This narrative review will focus on the characteristics of the different animal pneumococcal pneumonia models. The assessment of the different animal models will include considerations regarding pneumococcal strains, microbiology properties, procedures used for bacterial inoculation, pathogenesis, clinical characteristics, diagnosis, treatment, and preventive approaches.
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Mechanical ventilation and Streptococcus pneumoniae pneumonia alter mitochondrial homeostasis. Sci Rep 2018; 8:11718. [PMID: 30082877 PMCID: PMC6078986 DOI: 10.1038/s41598-018-30226-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/23/2018] [Indexed: 12/16/2022] Open
Abstract
Required mechanical ventilation (MV) may contribute to bacterial dissemination in patients with Streptococcus pneumoniae pneumonia. Significant variations in plasma mitochondrial DNA (mtDNA) have been reported in sepsis according to the outcome. The impact of lung stretch during MV was addressed in a model of pneumonia. Healthy or S. pneumoniae infected rabbits were submitted to MV or kept spontaneously breathing (SB). Bacterial burden, cytokines release, mitochondrial DNA levels, integrity and transcription were assessed along with 48-hour mortality. Compared with infected SB rabbits, MV rabbits developed more severe pneumonia with greater concentrations of bacteria in the lungs, higher rates of systemic dissemination, higher levels of circulating inflammatory mediators and decreased survival. Pulmonary mtDNA levels were significantly lower in infected animals as compared to non-infected ones, whenever they were SB or MV. After a significant early drop, circulating mtDNA levels returned to baseline values in the infected SB rabbits, but remained low until death in the MV ones. Whole blood ex-vivo stimulation with Streptococcus pneumoniae resulted in a reduction of polymorphonuclear leukocytes mitochondrial density and plasma mtDNA concentrations. Thus, persistent mitochondrial depletion and dysfunction in the infected animals submitted to MV could account for their less efficient immune response against S. pneumoniae.
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Pauchard LA, Blot M, Bruyere R, Barbar SD, Croisier D, Piroth L, Charles PE. Linezolid and atorvastatin impact on pneumonia caused by Staphyloccocus aureus in rabbits with or without mechanical ventilation. PLoS One 2017; 12:e0187187. [PMID: 29149185 PMCID: PMC5693480 DOI: 10.1371/journal.pone.0187187] [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: 05/31/2017] [Accepted: 10/16/2017] [Indexed: 01/01/2023] Open
Abstract
Pneumonia may involve methicillin-resistant Staphylococcus aureus (MRSA), with elevated rates of antibiotics failure. The present study aimed to assess the effect of statins given prior to pneumonia development. Spontaneously breathing (SB) or mechanically ventilated (MV) rabbits with pneumonia received atorvastatin alone, linezolid (LNZ) alone, or a combination of both (n = 5 in each group). Spontaneously breathing and MV untreated infected animals (n = 11 in each group), as well as uninfected animals (n = 5 in each group) were used as controls. Microbiological features and inflammation were evaluated. Data are presented as medians (interquartile range). Linezolid alone tended to reduce pulmonary MRSA load in both SB and MV rabbits, but failed to prevent bacteremia (59%) in the latter. Linezolid alone dampened TNF-α lung production in both SB and MV rabbits (e.g., 2226 [789] vs. 11478 [10251] pg/g; p = 0.022). Statins alone did the same in both SB and MV animals (e.g., 2040 [133]; p = 0.016), and dampened systemic inflammation in the latter, possibly through TLR2 down-regulation within the lung. However, the combination of LNZ and statin led to an increased rate of bacteremia in MV animals up to 75%. Statins provide an anti-inflammatory effect in rabbits with MRSA pneumonia, especially in MV ones. However, dampening the systemic inflammatory response with statins could impede blood defenses against MRSA.
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Affiliation(s)
- Laure-Anne Pauchard
- Laboratoire “Lipides Nutrition Cancer”, U.M.R. 1231, I.N.S.E.R.M., U.F.R. Sciences de Santé, Université de Bourgogne, Dijon, France
| | - Mathieu Blot
- Laboratoire “Lipides Nutrition Cancer”, U.M.R. 1231, I.N.S.E.R.M., U.F.R. Sciences de Santé, Université de Bourgogne, Dijon, France
- Service des Maladies Infectieuses et Tropicales, Hôpital F. Mitterrand, Dijon, France
| | - Rémi Bruyere
- Laboratoire “Lipides Nutrition Cancer”, U.M.R. 1231, I.N.S.E.R.M., U.F.R. Sciences de Santé, Université de Bourgogne, Dijon, France
| | - Saber-Davide Barbar
- Laboratoire “Lipides Nutrition Cancer”, U.M.R. 1231, I.N.S.E.R.M., U.F.R. Sciences de Santé, Université de Bourgogne, Dijon, France
| | | | - Lionel Piroth
- Service des Maladies Infectieuses et Tropicales, Hôpital F. Mitterrand, Dijon, France
| | - Pierre-Emmanuel Charles
- Laboratoire “Lipides Nutrition Cancer”, U.M.R. 1231, I.N.S.E.R.M., U.F.R. Sciences de Santé, Université de Bourgogne, Dijon, France
- Service de Réanimation Médicale, Hôpital F. Mitterrand, Dijon, France
- * E-mail:
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Reupke V, Walliser K, Perl T, Kimmina S, Schraepler A, Quintel M, Kunze-Szikszay N. Total intravenous anaesthesia using propofol and sufentanil allows controlled long-term ventilation in rabbits without neuromuscular blocking agents. Lab Anim 2016; 51:284-291. [PMID: 27413175 DOI: 10.1177/0023677216660337] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aim of this study was to evaluate a total intravenous anaesthesia (TIVA) protocol using propofol and sufentanil without neuromuscular blocking agents (NBAs) for a non-recovery lung pathology study in rabbits including 10 h of pressure-controlled ventilation. TIVA was started with 20 mg/kg/h propofol and 0.5 µg/kg/h sufentanil. The depth of anaesthesia was assessed by reflex testing and monitoring of spontaneous movements or respiratory efforts. Vital parameters were monitored to assess the effects of the TIVA protocol. The infusion rates were increased whenever reflex testing indicated inadequate depth of anaesthesia, and were reduced when vital parameters indicated unnecessarily deep levels. Median infusion rates of 35 mg/kg/h propofol and 2.0 µg/kg/h sufentanil were needed to ensure an adequate depth of anaesthesia. This protocol suppressed spontaneous movements, breathing and palpebral reflexes, but was unable to suppress corneal and pedal withdrawal reflexes. Since significant drops in arterial blood pressure (ABP) were observed and the animals were not exposed to painful procedures, positive corneal and pedal withdrawal reflexes were tolerated. In conclusion, propofol and sufentanil is a suitable combination for long-term anaesthesia in non-recovery lung pathology models in rabbits without painful procedures. ABP must be monitored carefully because of the circulatory side-effects, but it is an inappropriate surrogate marker for depth of anaesthesia. Due to the lack of neuromuscular blockade this TIVA protocol allows the adjustment of infusion rates based on reflex testing. The resulting decreased risk of unnoticed awareness is a decisive refinement in anaesthesia for similar studies including long-term mechanical ventilation in rabbits.
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Affiliation(s)
- Verena Reupke
- 1 Central Animal Facility, University Medical Centre Göttingen, Göttingen, Germany
| | - Karoline Walliser
- 2 Department of Anaesthesiology, University Medical Centre Göttingen, Göttingen, Germany
| | - Thorsten Perl
- 2 Department of Anaesthesiology, University Medical Centre Göttingen, Göttingen, Germany
| | - Sarah Kimmina
- 3 Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Anke Schraepler
- 1 Central Animal Facility, University Medical Centre Göttingen, Göttingen, Germany
| | - Michael Quintel
- 2 Department of Anaesthesiology, University Medical Centre Göttingen, Göttingen, Germany
| | - Nils Kunze-Szikszay
- 2 Department of Anaesthesiology, University Medical Centre Göttingen, Göttingen, Germany
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Barbar SD, Pauchard LA, Bruyère R, Bruillard C, Hayez D, Croisier D, Pugin J, Charles PE. Mechanical Ventilation Alters the Development of Staphylococcus aureus Pneumonia in Rabbit. PLoS One 2016; 11:e0158799. [PMID: 27391952 PMCID: PMC4938582 DOI: 10.1371/journal.pone.0158799] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 06/22/2016] [Indexed: 12/18/2022] Open
Abstract
Ventilator-associated pneumonia (VAP) is common during mechanical ventilation (MV). Beside obvious deleterious effects on muco-ciliary clearance, MV could adversely shift the host immune response towards a pro-inflammatory pattern through toll-like receptor (TLRs) up-regulation. We tested this hypothesis in a rabbit model of Staphylococcus aureus VAP. Pneumonia was caused by airway challenge with S. aureus, in either spontaneously breathing (SB) or MV rabbits (n = 13 and 17, respectively). Pneumonia assessment regarding pulmonary and systemic bacterial burden, as well as inflammatory response was done 8 and 24 hours after S. aureus challenge. In addition, ex vivo stimulations of whole blood taken from SB or MV rabbits (n = 7 and 5, respectively) with TLR2 agonist or heat-killed S. aureus were performed. Data were expressed as mean±standard deviation. After 8 hours of infection, lung injury was more severe in MV animals (1.40±0.33 versus [vs] 2.40±0.55, p = 0.007), along with greater bacterial concentrations (6.13±0.63 vs. 4.96±1.31 colony forming units/gram, p = 0.002). Interleukin (IL)-8 and tumor necrosis factor (TNF)-αserum concentrations reached higher levels in MV animals (p = 0.010). Whole blood obtained from MV animals released larger amounts of cytokines if stimulated with TLR2 agonist or heat-killed S. aureus (e.g., TNF-α: 1656±166 vs. 1005±89; p = 0.014). Moreover, MV induced TLR2 overexpression in both lung and spleen tissue. MV hastened tissue injury, impaired lung bacterial clearance, and promoted a systemic inflammatory response, maybe through TLR2 overexpression.
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Affiliation(s)
- Saber-Davide Barbar
- Laboratoire “Ventilation Immunité Poumon”, Pôle Microbiologie Environnementale et Risque Sanitaire (M.E.R.S.), U.M.R. 1347, I.N.R.A., Université de Bourgogne, Dijon, France
| | - Laure-Anne Pauchard
- Laboratoire “Ventilation Immunité Poumon”, Pôle Microbiologie Environnementale et Risque Sanitaire (M.E.R.S.), U.M.R. 1347, I.N.R.A., Université de Bourgogne, Dijon, France
| | - Rémi Bruyère
- Laboratoire “Ventilation Immunité Poumon”, Pôle Microbiologie Environnementale et Risque Sanitaire (M.E.R.S.), U.M.R. 1347, I.N.R.A., Université de Bourgogne, Dijon, France
| | - Caroline Bruillard
- Laboratoire “Ventilation Immunité Poumon”, Pôle Microbiologie Environnementale et Risque Sanitaire (M.E.R.S.), U.M.R. 1347, I.N.R.A., Université de Bourgogne, Dijon, France
| | | | | | - Jérôme Pugin
- Intensive Care Laboratory, University Hospitals of Geneva, and Department of Microbiology and Molecular Medicine, Faculty of Medicine, 1211 Geneva 14, Switzerland
| | - Pierre-Emmanuel Charles
- Laboratoire “Ventilation Immunité Poumon”, Pôle Microbiologie Environnementale et Risque Sanitaire (M.E.R.S.), U.M.R. 1347, I.N.R.A., Université de Bourgogne, Dijon, France
- * E-mail:
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Müller-Redetzky HC, Will D, Hellwig K, Kummer W, Tschernig T, Pfeil U, Paddenberg R, Menger MD, Kershaw O, Gruber AD, Weissmann N, Hippenstiel S, Suttorp N, Witzenrath M. Mechanical ventilation drives pneumococcal pneumonia into lung injury and sepsis in mice: protection by adrenomedullin. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2014; 18:R73. [PMID: 24731244 PMCID: PMC4056010 DOI: 10.1186/cc13830] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 04/03/2014] [Indexed: 01/04/2023]
Abstract
Introduction Ventilator-induced lung injury (VILI) contributes to morbidity and mortality in acute respiratory distress syndrome (ARDS). Particularly pre-injured lungs are susceptible to VILI despite protective ventilation. In a previous study, the endogenous peptide adrenomedullin (AM) protected murine lungs from VILI. We hypothesized that mechanical ventilation (MV) contributes to lung injury and sepsis in pneumonia, and that AM may reduce lung injury and multiple organ failure in ventilated mice with pneumococcal pneumonia. Methods We analyzed in mice the impact of MV in established pneumonia on lung injury, inflammation, bacterial burden, hemodynamics and extrapulmonary organ injury, and assessed the therapeutic potential of AM by starting treatment at intubation. Results In pneumococcal pneumonia, MV increased lung permeability, and worsened lung mechanics and oxygenation failure. MV dramatically increased lung and blood cytokines but not lung leukocyte counts in pneumonia. MV induced systemic leukocytopenia and liver, gut and kidney injury in mice with pneumonia. Lung and blood bacterial burden was not affected by MV pneumonia and MV increased lung AM expression, whereas receptor activity modifying protein (RAMP) 1–3 expression was increased in pneumonia and reduced by MV. Infusion of AM protected against MV-induced lung injury (66% reduction of pulmonary permeability p < 0.01; prevention of pulmonary restriction) and against VILI-induced liver and gut injury in pneumonia (91% reduction of AST levels p < 0.05, 96% reduction of alanine aminotransaminase (ALT) levels p < 0.05, abrogation of histopathological changes and parenchymal apoptosis in liver and gut). Conclusions MV paved the way for the progression of pneumonia towards ARDS and sepsis by aggravating lung injury and systemic hyperinflammation leading to liver, kidney and gut injury. AM may be a promising therapeutic option to protect against development of lung injury, sepsis and extrapulmonary organ injury in mechanically ventilated individuals with severe pneumonia.
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Impact of the Prone Position in an Animal Model of Unilateral Bacterial Pneumonia Undergoing Mechanical Ventilation. Anesthesiology 2013; 118:1150-9. [DOI: 10.1097/aln.0b013e31828a7016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Abstract
Background:
The prone position (PP) has proven beneficial in patients with severe lung injury subjected to mechanical ventilation (MV), especially in those with lobar involvement. We assessed the impact of PP on unilateral pneumonia in rabbits subjected to MV.
Methods:
After endobronchial challenge with Enterobacter aerogenes, adult rabbits were subjected to either “adverse” (peak inspiratory pressure = 30 cm H2O, zero end-expiratory pressure; n = 10) or “protective” (tidal volume = 8 ml/kg, 5 cm H2O positive end-expiratory pressure; n = 10) MV and then randomly kept supine or turned to the PP. Pneumonia was assessed 8 h later. Data are presented as median (interquartile range).
Results:
Compared with the supine position, PP was associated with significantly lower bacterial concentrations within the infected lung, even if a “protective” MV was applied (5.93 [0.34] vs. 6.66 [0.86] log10 cfu/g, respectively; P = 0.008). Bacterial concentrations in the spleen were also decreased by the PP if the “adverse” MV was used (3.62 [1.74] vs. 6.55 [3.67] log10 cfu/g, respectively; P = 0.038). In addition, the noninfected lung was less severely injured in the PP group. Finally, lung and systemic inflammation as assessed through interleukin-8 and tumor necrosis factor-α measurement was attenuated by the PP.
Conclusions:
The PP could be protective if the host is subjected to MV and unilateral bacterial pneumonia. It improves lung injury even if it is utilized after lung injury has occurred and nonprotective ventilation has been administered.
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Use of airway pressure release ventilation is associated with a reduced incidence of ventilator-associated pneumonia in patients with pulmonary contusion. ACTA ACUST UNITED AC 2011; 70:E42-7. [PMID: 20526208 DOI: 10.1097/ta.0b013e3181d9f612] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND Past studies suggest that airway pressure release ventilation (APRV) is associated with reduced sedative requirements and increased recruitment of atelectatic lung, two factors that might reduce the risk for ventilator-associated pneumonia (VAP). We investigated whether APRV might be associated with a decreased risk for VAP in patients with pulmonary contusion. MATERIALS Retrospective cohort study. RESULTS Of 286, 64 (22%) patients requiring mechanical ventilation for >48 hours met criteria for pulmonary contusion and were the basis for this study. Subjects with pulmonary contusion had a significantly higher rate of VAP than other trauma patients, [VAP rate contusion patients: 18.3/1,000, non-contusion patients: 7.7/1,000, incidence rate ratio 2.37 (95% confidence interval [CI], 1.11-4.97), p=0.025]. Univariate analysis showed that APRV (hazard ratio, 0.15 [0.03-0.72; p=0.018]) was associated with a decreased incidence of VAP. Cox proportional hazards regression, using propensity scores for APRV to control for confounding, supported a protective effect of APRV from VAP (hazard ratio, 0.10 [95% CI, 0.02-0.58]; p=0.01). Pao2/FiO2 ratios were higher during APRV compared with conventional ventilation (p<0.001). Subjects attained the goal Sedation Agitation Score for an increased percentage of time during APRV (median [interquartile range (IQR)] 72.7% [33-100] of the time) compared with conventional ventilation (47.2% [0-100], p=0.044), however, dose of sedatives was not different between these subjects. APRV was not associated with hospital mortality (odds ratio 0.57 [95% CI, 0.06-5.5]; p=0.63) or ventilator-free days (No APRV 15.4 vs. APRV 13.7 days, p=0.49). CONCLUSION Use of APRV in patients with pulmonary contusion is associated with a reduced risk for VAP.
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Wu Q, Gui P, Yao S, Zhu H, Li J, Li Y. Expression of β-Defensin-3 in Lungs of Immunocompetent Rats with Methicillin-Resistant Staphylococcus aureus Ventilator-Associated Pneumonia. J Surg Res 2011; 169:277-83. [DOI: 10.1016/j.jss.2009.12.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 11/13/2009] [Accepted: 12/11/2009] [Indexed: 01/15/2023]
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Charles PE, Tissières P, Barbar SD, Croisier D, Dufour J, Dunn-Siegrist I, Chavanet P, Pugin J. Mild-stretch mechanical ventilation upregulates toll-like receptor 2 and sensitizes the lung to bacterial lipopeptide. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2011; 15:R181. [PMID: 21794115 PMCID: PMC3387624 DOI: 10.1186/cc10330] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 07/01/2011] [Accepted: 07/27/2011] [Indexed: 01/17/2023]
Abstract
Introduction Mechanical ventilation (MV) could prime the lung toward an inflammatory response if exposed to another insult such as bacterial invasion. The underlying mechanisms are not so far clear. Toll-like receptors (TLRs) allow the host to recognize selectively bacterial pathogens and in turn to trigger an immune response. We therefore hypothesized that MV modulates TLR2 expression and in turn modifies responsiveness to agonists such as bacterial lipopeptide (BLP). Method Both in vitro and in vivo experiments were conducted. First, TLR2 expression and protein were measured in the A549 pulmonary epithelial cell line submitted to 8-hour cyclic stretch (20% elongation; 20/minute rate). After a 24-hour period of cyclic stretch, the inflammatory response of the A549 cells to the synthetic BLP, Pam3CSK4, was tested after 8 hours of exposure. In a second set of experiments, healthy anesthetized and paralyzed rabbits were submitted to 8-hour MV (tidal volume = 12 ml/kg, zero end-expiratory pressure; FIO2 = 50%; respiratory rate = 20/minute) before being sacrificed for TLR2 lung expression assessment. The lung inflammatory response to BLP was then tested in animals submitted to 24-hour MV before being sacrificed 8 hours after the tracheal instillation of Pam3CSK4. Results Cyclic stretch of human pulmonary epithelial cell lines increased both TLR2 mRNA and protein expression. Cells submitted to cyclic stretch also increased IL-6 and IL-8 secretion in response to Pam3CSK4, a classical TLR2 ligand. A mild-stretch MV protocol induced a 60-fold increase of TLR2 mRNA expression in lung tissue when compared with spontaneously breathing controls. Moreover, the combination of MV and airway exposure to Pam3CSK4 acted synergistically in causing lung inflammation and injury. Conclusions Mild-stretch MV increases lung expression of TLR2 and sensitizes the lung to bacterial TLR2 ligands. This may account for the propensity of mechanically ventilated patients to develop acute lung injury in the context of airway bacterial colonization/infection.
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Affiliation(s)
- Pierre-Emmanuel Charles
- Laboratoire Interactions Muqueuses Agents Pathogènes, EA562, UFR Médecine, Université de Bourgogne, 7 Bd Jeanne d'Arc, 21000 Dijon, France.
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Charles PE, Barbar SD. Toll-like receptors: a link between mechanical ventilation, innate immunity and lung injury? Intensive Care Med 2010; 36:909-11. [PMID: 20397010 DOI: 10.1007/s00134-010-1804-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 02/12/2010] [Indexed: 10/19/2022]
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Propagation prevention: a complementary mechanism for "lung protective" ventilation in acute respiratory distress syndrome. Crit Care Med 2008; 36:3252-8. [PMID: 18936705 DOI: 10.1097/ccm.0b013e31818f0e68] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE To describe the clinical implications of an often neglected mechanism through which localized acute lung injury may be propagated and intensified. DATA EXTRACTION AND SYNTHESIS Experimental and clinical evidence from the medical literature relevant to the airway propagation hypothesis and its consequences. CONCLUSIONS The diffuse injury that characterizes acute respiratory distress syndrome is often considered a process that begins synchronously throughout the lung, mediated by inhaled or blood-borne noxious agents. Relatively little attention has been paid to possibility that inflammatory lung injury may also begin focally and propagate sequentially via the airway network, proceeding mouth-ward from distal to proximal. Were this true, modifications of ventilatory pattern and position aimed at geographic containment of the injury process could help prevent its generalization and limit disease severity. The purposes of this communication are to call attention to this seldom considered mechanism for extending lung injury that might further justify implementation of low tidal volume/high positive end-expiratory pressure ventilatory strategies for lung protection and to suggest additional therapeutic measures implied by this broadened conceptual paradigm.
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Abstract
SUMMARY Streptococcus pneumoniae is a colonizer of human nasopharynx, but it is also an important pathogen responsible for high morbidity, high mortality, numerous disabilities, and high health costs throughout the world. Major diseases caused by S. pneumoniae are otitis media, pneumonia, sepsis, and meningitis. Despite the availability of antibiotics and vaccines, pneumococcal infections still have high mortality rates, especially in risk groups. For this reason, there is an exceptionally extensive research effort worldwide to better understand the diseases caused by the pneumococcus, with the aim of developing improved therapeutics and vaccines. Animal experimentation is an essential tool to study the pathogenesis of infectious diseases and test novel drugs and vaccines. This article reviews both historical and innovative laboratory pneumococcal animal models that have vastly added to knowledge of (i) mechanisms of infection, pathogenesis, and immunity; (ii) efficacies of antimicrobials; and (iii) screening of vaccine candidates. A comprehensive description of the techniques applied to induce disease is provided, the advantages and limitations of mouse, rat, and rabbit models used to mimic pneumonia, sepsis, and meningitis are discussed, and a section on otitis media models is also included. The choice of appropriate animal models for in vivo studies is a key element for improved understanding of pneumococcal disease.
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Do airway secretions play an underappreciated role in acute respiratory distress syndrome? Curr Opin Crit Care 2008; 14:44-9. [PMID: 18195625 DOI: 10.1097/mcc.0b013e3282f2f4cb] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW We review the evidence that airway secretions may have an underappreciated role in acute respiratory distress syndrome, contributing to physiologic disarrangements, ventilator dependence and perhaps to injury generation. As common manipulations of ventilator settings, position and fluid status have the potential to influence these problems, explorations into the secretion dynamics of acute lung injury may be fertile ground for developing therapeutic advances. RECENT FINDINGS Principles that govern the interaction of airflow and airway fluids suggest that mobile fluids and secretions are pumped by well-selected ventilatory patterns toward the airway opening. Conversely, other selections may inhibit these fluids from clearance or encourage their translocation between lung regions. Recent laboratory work demonstrates that choices for tidal volume and positive end-expiratory pressure may localize or disperse proteinaceous lung edema or bacteria. Gravitational factors may interact with ventilatory pattern for benefit or harm. SUMMARY Capability of ventilation and positioning to mobilize secretions implies the potential for clearance or containment of inflammatory mediators and infection. Ventilatory and positional prescriptions could be designed to meet one of either conflicting targets. Additional experimental and clinical investigations are required before adopting these proposed therapeutic principles into practice.
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Sartorius A, Lu Q, Vieira S, Tonnellier M, Lenaour G, Goldstein I, Rouby JJ. Mechanical ventilation and lung infection in the genesis of air-space enlargement. Crit Care 2007; 11:R14. [PMID: 17274806 PMCID: PMC2147711 DOI: 10.1186/cc5680] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Revised: 11/22/2006] [Accepted: 02/02/2007] [Indexed: 11/24/2022] Open
Abstract
Introduction Air-space enlargement may result from mechanical ventilation and/or lung infection. The aim of this study was to assess how mechanical ventilation and lung infection influence the genesis of bronchiolar and alveolar distention. Methods Four groups of piglets were studied: non-ventilated-non-inoculated (controls, n = 5), non-ventilated-inoculated (n = 6), ventilated-non-inoculated (n = 6), and ventilated-inoculated (n = 8) piglets. The respiratory tract of intubated piglets was inoculated with a highly concentrated solution of Escherichia coli. Mechanical ventilation was maintained during 60 hours with a tidal volume of 15 ml/kg and zero positive end-expiratory pressure. After sacrifice by exsanguination, lungs were fixed for histological and lung morphometry analyses. Results Lung infection was present in all inoculated piglets and in five of the six ventilated-non-inoculated piglets. Mean alveolar and mean bronchiolar areas, measured using an analyzer computer system connected through a high-resolution color camera to an optical microscope, were significantly increased in non-ventilated-inoculated animals (+16% and +11%, respectively, compared to controls), in ventilated-non-inoculated animals (+49% and +49%, respectively, compared to controls), and in ventilated-inoculated animals (+95% and +118%, respectively, compared to controls). Mean alveolar and mean bronchiolar areas significantly correlated with the extension of lung infection (R = 0.50, p < 0.01 and R = 0.67, p < 0.001, respectively). Conclusion Lung infection induces bronchiolar and alveolar distention. Mechanical ventilation induces secondary lung infection and is associated with further air-space enlargement. The combination of primary lung infection and mechanical ventilation markedly increases air-space enlargement, the degree of which depends on the severity and extension of lung infection.
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Affiliation(s)
- Alfonso Sartorius
- Surgical Intensive Care Unit Pierre Viars, Department of Anesthesiology, Assistance Publique-Hôpitaux de Paris, La Pitié-Salpêtrière Hospital, 47-83 boulevard de l'Hôpital, 75013 Paris, France
| | - Qin Lu
- Surgical Intensive Care Unit Pierre Viars, Department of Anesthesiology, Assistance Publique-Hôpitaux de Paris, La Pitié-Salpêtrière Hospital, 47-83 boulevard de l'Hôpital, 75013 Paris, France
| | - Silvia Vieira
- Department of Internal Medicine, Faculty of Medicine, Federal University from Rio Grande do Sul, Intensive Care Unit, Hospital de Clinicas de Porto Alegre, Rua Ramiro Barcelos, 2350 – 90035-903 Porto Alegre/Rio Grande do Sul, Brazil
| | - Marc Tonnellier
- Medical Intensive Care Unit, Assistance Publique-Hôpitaux de Paris, La Pitié-Salpêtrière Hospital, 47-83 boulevard de l'Hôpital, 75013 Paris, France
| | - Gilles Lenaour
- Department of Pathology, Assistance Publique-Hôpitaux de Paris, La Pitié-Salpêtrière Hospital, 47-83 boulevard de l'Hôpital, 75013 Paris, France
| | - Ivan Goldstein
- Surgical Intensive Care Unit Pierre Viars, Department of Anesthesiology, Assistance Publique-Hôpitaux de Paris, La Pitié-Salpêtrière Hospital, 47-83 boulevard de l'Hôpital, 75013 Paris, France
| | - Jean-Jacques Rouby
- Surgical Intensive Care Unit Pierre Viars, Department of Anesthesiology, Assistance Publique-Hôpitaux de Paris, La Pitié-Salpêtrière Hospital, 47-83 boulevard de l'Hôpital, 75013 Paris, France
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Charles PE, Etienne M, Croisier D, Piroth L, Lequeu C, Pugin J, Portier H, Chavanet P. The impact of mechanical ventilation on the moxifloxacin treatment of experimental pneumonia caused by Streptococcus pneumoniae. Crit Care Med 2005; 33:1029-35. [PMID: 15891332 DOI: 10.1097/01.ccm.0000163404.35338.72] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Streptococcus pneumoniae is a leading cause of community-acquired pneumonia and is responsible for early-onset ventilator-associated pneumonia as well. In intensive care units, community-acquired pneumonia is still associated with a mortality rate of up to 30%, especially when mechanical ventilation is required. Our objective was to study to what extent MV could influence the efficacy of moxifloxacin in a rabbit model of pneumonia. DESIGN Prospective experimental study. SETTING University hospital laboratory. SUBJECTS Male New Zealand White rabbits (n = 75). INTERVENTIONS S. pneumoniae (16089 strain; minimal inhibitory concentration for moxifloxacin = 0.125 mg/L) was instilled intrabronchially. Four hours later, a human-like moxifloxacin treatment was initiated in spontaneously breathing (SB) and mechanically ventilated (MV) animals. Untreated rabbits were used as controls. Survivors were killed 48 hrs later. Pneumonia was assessed and moxifloxacin pharmacokinetics were analyzed. MEASUREMENTS AND MAIN RESULTS Moxifloxacin treatment was associated with an improvement in survival in the SB animals (13 of 13 [100%] vs. eight of 37 [21.6%] controls). The survival rate was less influenced by treatment in MV rabbits (seven of 15 [46.1%] vs. one of eight [12.5%] controls). The lung bacterial burden was greater in MV compared with SB rabbits (5.1 +/- 2.4 vs. 1.6 +/- 1.4 log10 colony-forming units/g, respectively). Nearly all the untreated animals presented bacteremia as reflected by a positive spleen culture. No bacteremia was found in SB animals treated with moxifloxacin. In contrast, three of 13 (23.1%) moxifloxacin-treated and MV animals had positive spleen cultures. The apparent volume of distribution of moxifloxacin was lower in MV compared with SB rabbits. CONCLUSIONS In our model of moxifloxacin-treated S. pneumoniae pneumonia, mechanical ventilation was associated with a higher mortality rate and seemed to promote bacterial growth as well as systemic spread of the infection. In addition, the volume of distribution of moxifloxacin was reduced in the presence of mechanical ventilation. Although the roles of factors such as anesthesia, paralysis, and endotracheal tube insertion could not be established, these results suggest that mechanical ventilation may impair host lung defense, rendering antibiotic therapy less effective.
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Charles PE, Martin L, Etienne M, Croisier D, Piroth L, Lequeu C, Pugin J, Portier H, Chavanet P. Influence of positive end-expiratory pressure (PEEP) on histopathological and bacteriological aspects of pneumonia during low tidal volume mechanical ventilation. Intensive Care Med 2004; 30:2263-70. [PMID: 15536527 PMCID: PMC7095170 DOI: 10.1007/s00134-004-2442-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Accepted: 08/24/2004] [Indexed: 12/03/2022]
Abstract
Objective Ventilatory strategies combining low tidal volume (VT) with positive end-expiratory pressure (PEEP) are considered to be lung protective. The influence of the PEEP level was investigated on bacteriology and histology in a model of ventilator-associated pneumonia. Subjects Nineteen New Zealand rabbits. Interventions The animals were mechanically ventilated with a positive inspiratory pressure of 15 cmH2O and received either a zero end-expiratory pressure (ZEEP, n=6), a 5 cmH2O PEEP (n=5) or a 10 cmH2O PEEP (n=4). An inoculum of Enterobacter aerogenes was then instilled intrabronchially. The non-ventilated pneumonia group (n=4) was composed of spontaneously breathing animals which received the same inoculum. Pneumonia was assessed 24 h later. Main results The lung bacterial burden was higher in mechanically ventilated animals compared with spontaneously breathing animals. All animals from the latter group had negative spleen cultures. The spleen bacterial concentration was found to be lower in the 5 cmH2O PEEP group when compared to the ZEEP and 10 cmH2O PEEP groups (3.1±1.5 vs 4.9±1.1 and 5.0±1.3 log10 cfu/g, respectively; p<0.05). Lung weight and histological score values were lower in the spontaneously breathing animals as well as in the 5 cmH2O PEEP group compared with the ZEEP and 10 cmH2O groups. Conclusions Mechanical ventilation substantially increased the lung bacterial burden and worsened the histological aspects of pneumonia in this rabbit model. Variations in terms of lung injury and systemic spreading of infection were noted with respect to the ventilatory strategy.
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Affiliation(s)
- Pierre Emmanuel Charles
- Laboratoire des Maladies Infectieuses, EA562, Dijon University Hospital, Boulevard Mal de Lattre de Tassigny, 21033 Dijon, France.
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Kurahashi K, Ota S, Nakamura K, Nagashima Y, Yazawa T, Satoh M, Fujita A, Kamiya R, Fujita E, Baba Y, Uchida K, Morimura N, Andoh T, Yamada Y. Effect of lung-protective ventilation on severePseudomonas aeruginosapneumonia and sepsis in rats. Am J Physiol Lung Cell Mol Physiol 2004; 287:L402-10. [PMID: 15107296 DOI: 10.1152/ajplung.00435.2003] [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: 11/22/2022] Open
Abstract
Pneumonia caused by Pseudomonas aeruginosa carries a high rate of morbidity and mortality. A lung-protective strategy using low tidal volume (VT) ventilation for acute lung injury improves patient outcomes. The goal of this study was to determine whether low VTventilation has similar utility in severe P. aeruginosa infection. A cytotoxic P. aeruginosa strain, PA103, was instilled into the left lung of rats anesthetized with pentobarbital. The lung-protective effect of low VT(6 ml/kg) with or without high positive end-expiratory pressure (PEEP, 10 or 3 cmH2O) was then compared with high VTwith low PEEP ventilation (VT12 ml/kg, PEEP 3 cmH2O). Severe lung injury and septic shock was induced. Although ventilatory mode had little effect on the involved lung or septic physiology, injury to noninvolved regions was attenuated by low VTventilation as indicated by the wet-to-dry weight ratio (W/D; 6.13 ± 0.78 vs. 3.78 ± 0.26, respectively) and confirmed by histopathological examinations. High PEEP did not yield a significant protective effect (W/D, 4.03 ± 0.32) but, rather, caused overdistension of noninvolved lungs. Bronchoalveolar lavage revealed higher concentrations of TNF-α in the fluid of noninvolved lung undergoing high VTventilation compared with those animals receiving low VT. We conclude that low VTventilation is protective in noninvolved regions and that the application of high PEEP attenuated the beneficial effects of low VTventilation, at least short term. Furthermore, low VTventilation cannot protect the involved lung, and high PEEP did not significantly alter lung injury over a short time course.
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Affiliation(s)
- Kiyoyasu Kurahashi
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan, 236-0004.
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Piacentini E, Villagrá A, López-Aguilar J, Blanch L. Clinical review: the implications of experimental and clinical studies of recruitment maneuvers in acute lung injury. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2003; 8:115-21. [PMID: 15025772 PMCID: PMC420020 DOI: 10.1186/cc2364] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Mechanical ventilation can cause and perpetuate lung injury if alveolar overdistension, cyclic collapse, and reopening of alveolar units occur. The use of low tidal volume and limited airway pressure has improved survival in patients with acute lung injury or acute respiratory distress syndrome. The use of recruitment maneuvers has been proposed as an adjunct to mechanical ventilation to re-expand collapsed lung tissue. Many investigators have studied the benefits of recruitment maneuvers in healthy anesthetized patients and in patients ventilated with low positive end-expiratory pressure. However, it is unclear whether recruitment maneuvers are useful when patients with acute lung injury or acute respiratory distress syndrome are ventilated with high positive end-expiratory pressure, and in the presence of lung fibrosis or a stiff chest wall. Moreover, it is unclear whether the use of high airway pressures during recruitment maneuvers can cause bacterial translocation. This article reviews the intrinsic mechanisms of mechanical stress, the controversy regarding clinical use of recruitment maneuvers, and the interactions between lung infection and application of high intrathoracic pressures.
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Affiliation(s)
- Enrique Piacentini
- Research Fellow, Critical Care Centre, Hospital de Sabadell, Institut Universitari Parc Taulí, Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Ana Villagrá
- Research Fellow, Critical Care Centre, Hospital de Sabadell, Institut Universitari Parc Taulí, Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Josefina López-Aguilar
- Researcher, Critical Care Centre, Hospital de Sabadell, Institut Universitari Parc Taulí, Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Lluis Blanch
- Executive Director, Critical Care Centre, Hospital de Sabadell, Institut Universitari Parc Taulí, Universitat Autònoma de Barcelona, Sabadell, Spain
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