1
|
Mikolka P, Kosutova P, Kolomaznik M, Nemcova N, Hanusrichterova J, Curstedt T, Johansson J, Calkovska A. The Synthetic Surfactant CHF5633 Restores Lung Function and Lung Architecture in Severe Acute Respiratory Distress Syndrome in Adult Rabbits. Lung 2024; 202:299-315. [PMID: 38684519 PMCID: PMC11143048 DOI: 10.1007/s00408-024-00689-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 03/23/2024] [Indexed: 05/02/2024]
Abstract
PURPOSE Acute respiratory distress syndrome (ARDS) is a major cause of hypoxemic respiratory failure in adults. In ARDS extensive inflammation and leakage of fluid into the alveoli lead to dysregulation of pulmonary surfactant metabolism and function. Altered surfactant synthesis, secretion, and breakdown contribute to the clinical features of decreased lung compliance and alveolar collapse. Lung function in ARDS could potentially be restored with surfactant replacement therapy, and synthetic surfactants with modified peptide analogues may better withstand inactivation in ARDS alveoli than natural surfactants. METHODS This study aimed to investigate the activity in vitro and the bolus effect (200 mg phospholipids/kg) of synthetic surfactant CHF5633 with analogues of SP-B and SP-C, or natural surfactant Poractant alfa (Curosurf®, both preparations Chiesi Farmaceutici S.p.A.) in a severe ARDS model (the ratio of partial pressure arterial oxygen and fraction of inspired oxygen, P/F ratio ≤ 13.3 kPa) induced by hydrochloric acid instillation followed by injurious ventilation in adult New Zealand rabbits. The animals were ventilated for 4 h after surfactant treatment and the respiratory parameters, histological appearance of lung parenchyma and levels of inflammation, oxidative stress, surfactant dysfunction, and endothelial damage were evaluated. RESULTS Both surfactant preparations yielded comparable improvements in lung function parameters, reductions in lung injury score, pro-inflammatory cytokines levels, and lung edema formation compared to untreated controls. CONCLUSIONS This study indicates that surfactant replacement therapy with CHF5633 improves lung function and lung architecture, and attenuates inflammation in severe ARDS in adult rabbits similarly to Poractant alfa. Clinical trials have so far not yielded conclusive results, but exogenous surfactant may be a valid supportive treatment for patients with ARDS given its anti-inflammatory and lung-protective effects.
Collapse
Affiliation(s)
- Pavol Mikolka
- Department of Physiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia.
| | - Petra Kosutova
- Biomedical Centre Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - Maros Kolomaznik
- Biomedical Centre Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - Nikolett Nemcova
- Department of Physiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - Juliana Hanusrichterova
- Biomedical Centre Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - Tore Curstedt
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Jan Johansson
- Department of Biosciences and Nutrition, Karolinska Institutet, Neo, Huddinge, Sweden
| | - Andrea Calkovska
- Department of Physiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| |
Collapse
|
2
|
Albert RK, Jurkovich GJ, Connett J, Helgeson ES, Keniston A, Voelker H, Lindberg S, Proper JL, Bochicchio G, Stein DM, Cain C, Tesoriero R, Brown CVR, Davis J, Napolitano L, Carver T, Cipolle M, Cardenas L, Minei J, Nirula R, Doucet J, Miller PR, Johnson J, Inaba K, Kao L. Sigh Ventilation in Patients With Trauma: The SiVent Randomized Clinical Trial. JAMA 2023; 330:1982-1990. [PMID: 37877609 PMCID: PMC10600720 DOI: 10.1001/jama.2023.21739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 10/15/2023] [Indexed: 10/26/2023]
Abstract
Importance Among patients receiving mechanical ventilation, tidal volumes with each breath are often constant or similar. This may lead to ventilator-induced lung injury by altering or depleting surfactant. The role of sigh breaths in reducing ventilator-induced lung injury among trauma patients at risk of poor outcomes is unknown. Objective To determine whether adding sigh breaths improves clinical outcomes. Design, Setting, and Participants A pragmatic, randomized trial of sigh breaths plus usual care conducted from 2016 to 2022 with 28-day follow-up in 15 academic trauma centers in the US. Inclusion criteria were age older than 18 years, mechanical ventilation because of trauma for less than 24 hours, 1 or more of 5 risk factors for developing acute respiratory distress syndrome, expected duration of ventilation longer than 24 hours, and predicted survival longer than 48 hours. Interventions Sigh volumes producing plateau pressures of 35 cm H2O (or 40 cm H2O for inpatients with body mass indexes >35) delivered once every 6 minutes. Usual care was defined as the patient's physician(s) treating the patient as they wished. Main Outcomes and Measures The primary outcome was ventilator-free days. Prespecified secondary outcomes included all-cause 28-day mortality. Results Of 5753 patients screened, 524 were enrolled (mean [SD] age, 43.9 [19.2] years; 394 [75.2%] were male). The median ventilator-free days was 18.4 (IQR, 7.0-25.2) in patients randomized to sighs and 16.1 (IQR, 1.1-24.4) in those receiving usual care alone (P = .08). The unadjusted mean difference in ventilator-free days between groups was 1.9 days (95% CI, 0.1 to 3.6) and the prespecified adjusted mean difference was 1.4 days (95% CI, -0.2 to 3.0). For the prespecified secondary outcome, patients randomized to sighs had 28-day mortality of 11.6% (30/259) vs 17.6% (46/261) in those receiving usual care (P = .05). No differences were observed in nonfatal adverse events comparing patients with sighs (80/259 [30.9%]) vs those without (80/261 [30.7%]). Conclusions and Relevance In a pragmatic, randomized trial among trauma patients receiving mechanical ventilation with risk factors for developing acute respiratory distress syndrome, the addition of sigh breaths did not significantly increase ventilator-free days. Prespecified secondary outcome data suggest that sighs are well-tolerated and may improve clinical outcomes. Trial Registration ClinicalTrials.gov Identifier: NCT02582957.
Collapse
Affiliation(s)
| | | | - John Connett
- Division of Biostatistics, University of Minnesota, Minneapolis
| | | | | | - Helen Voelker
- Division of Biostatistics, University of Minnesota, Minneapolis
| | - Sarah Lindberg
- Division of Biostatistics, University of Minnesota, Minneapolis
| | | | - Grant Bochicchio
- Department of Surgery, Washington University, St Louis, St Louis, Missouri
| | | | - Christian Cain
- Department of Surgery, University of Maryland, Baltimore
| | - Ron Tesoriero
- Department of Surgery, University of Maryland, Baltimore
| | | | - James Davis
- Department of Surgery, University of California San Francisco, Fresno
| | | | - Thomas Carver
- Department of Surgery, Medical College of Wisconsin, Milwaukee
| | - Mark Cipolle
- Department of Surgery, Lehigh Valley Health Network, Bethlehem, Pennsylvania
| | - Luis Cardenas
- Department of Surgery, Christiana Care Health System, Wilmington, Delaware
| | - Joseph Minei
- Department of Surgery, University of Texas Southwestern, Dallas
| | | | - Jay Doucet
- Department of Surgery, University of California San Diego
| | - Preston R. Miller
- Department of Surgery, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Jeffrey Johnson
- Department of Surgery, Henry Ford Hospital, Detroit, Michigan
| | - Kenji Inaba
- Department of Surgery, University of Southern California Los Angeles County
| | - Lillian Kao
- Department of Surgery, University of Texas, Houston
| |
Collapse
|
3
|
Dushianthan A, Grocott MPW, Murugan GS, Wilkinson TMA, Postle AD. Pulmonary Surfactant in Adult ARDS: Current Perspectives and Future Directions. Diagnostics (Basel) 2023; 13:2964. [PMID: 37761330 PMCID: PMC10528901 DOI: 10.3390/diagnostics13182964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/10/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a major cause of hypoxemic respiratory failure in adults, leading to the requirement for mechanical ventilation and poorer outcomes. Dysregulated surfactant metabolism and function are characteristic of ARDS. A combination of alveolar epithelial damage leading to altered surfactant synthesis, secretion, and breakdown with increased functional inhibition from overt alveolar inflammation contributes to the clinical features of poor alveolar compliance and alveolar collapse. Quantitative and qualitative alterations in the bronchoalveolar lavage and tracheal aspirate surfactant composition contribute to ARDS pathogenesis. Compared to neonatal respiratory distress syndrome (nRDS), replacement studies of exogenous surfactants in adult ARDS suggest no survival benefit. However, these studies are limited by disease heterogeneity, variations in surfactant preparations, doses, and delivery methods. More importantly, the lack of mechanistic understanding of the exact reasons for dysregulated surfactant remains a significant issue. Moreover, studies suggest an extremely short half-life of replaced surfactant, implying increased catabolism. Refining surfactant preparations and delivery methods with additional co-interventions to counteract surfactant inhibition and degradation has the potential to enhance the biophysical characteristics of surfactant in vivo.
Collapse
Affiliation(s)
- Ahilanandan Dushianthan
- National Institute for Health Research (NIHR) Southampton Biomedical Research Centre, University Hospital Southampton National Health System Foundation Trust, Southampton SO16 6YD, UK; (M.P.W.G.); (T.M.A.W.); (A.D.P.)
- Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Michael P. W. Grocott
- National Institute for Health Research (NIHR) Southampton Biomedical Research Centre, University Hospital Southampton National Health System Foundation Trust, Southampton SO16 6YD, UK; (M.P.W.G.); (T.M.A.W.); (A.D.P.)
- Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | | | - Tom M. A. Wilkinson
- National Institute for Health Research (NIHR) Southampton Biomedical Research Centre, University Hospital Southampton National Health System Foundation Trust, Southampton SO16 6YD, UK; (M.P.W.G.); (T.M.A.W.); (A.D.P.)
- Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Anthony D. Postle
- National Institute for Health Research (NIHR) Southampton Biomedical Research Centre, University Hospital Southampton National Health System Foundation Trust, Southampton SO16 6YD, UK; (M.P.W.G.); (T.M.A.W.); (A.D.P.)
- Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| |
Collapse
|
4
|
Horikami D, Toya N, Kobayashi K, Omori K, Nagata N, Murata T. L-PGDS-derived PGD2
attenuates acute lung injury by enhancing endothelial barrier formation. J Pathol 2019; 248:280-290. [DOI: 10.1002/path.5253] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 12/31/2018] [Accepted: 02/04/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Daiki Horikami
- Department of Animal Radiology; Graduate School of Agriculture and Life Sciences, The University of Tokyo; Tokyo Japan
| | - Naoki Toya
- Department of Animal Radiology; Graduate School of Agriculture and Life Sciences, The University of Tokyo; Tokyo Japan
| | - Koji Kobayashi
- Department of Animal Radiology; Graduate School of Agriculture and Life Sciences, The University of Tokyo; Tokyo Japan
| | - Keisuke Omori
- Department of Animal Radiology; Graduate School of Agriculture and Life Sciences, The University of Tokyo; Tokyo Japan
| | - Nanae Nagata
- Department of Animal Radiology; Graduate School of Agriculture and Life Sciences, The University of Tokyo; Tokyo Japan
| | - Takahisa Murata
- Department of Animal Radiology; Graduate School of Agriculture and Life Sciences, The University of Tokyo; Tokyo Japan
| |
Collapse
|
5
|
Nguyen TL, Perlman CE. Tracheal acid or surfactant instillation raises alveolar surface tension. J Appl Physiol (1985) 2018; 125:1357-1367. [PMID: 29771610 DOI: 10.1152/japplphysiol.00397.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Whether alveolar liquid surface tension, T, is elevated in the acute respiratory distress syndrome (ARDS) has not been demonstrated in situ in the lungs. Neither is it known how exogenous surfactant, which has failed to treat ARDS, affects in situ T. We aim to determine T in an acid-aspiration ARDS model before and after exogenous surfactant administration. In isolated rat lungs, we combine servo-nulling pressure measurement and confocal microscopy to determine alveolar liquid T according to the Laplace relation. Administering 0.01 N (pH 1.9) HCl solution by alveolar injection or tracheal instillation, to model gastric liquid aspiration, raises T. Subsequent surfactant administration fails to normalize T. Furthermore, in normal lungs, tracheal instillation of control saline or exogenous surfactant raises T. Lavaging the trachea with saline and injecting the lavage solution into the alveolus raises T, suggesting that tracheal instillation may wash T-raising airway contents to the alveolus. Adding 0.01 N HCl or 5 mM CaCl2-either of which aggregates mucins-to tracheal lavage solution reduces or eliminates the effect of lavage solution on alveolar T. Following tracheal saline instillation, liquid suctioned directly out of alveoli through a micropipette contains mucins. Additionally, alveolar injection of gastric mucin solution raises T. We conclude that 1) tracheal liquid instillation likely washes T-raising mucins to the alveolus and 2) even exogenous surfactant that could be delivered mucin-free to the alveolus might not normalize T in acid-aspiration ARDS. NEW & NOTEWORTHY We demonstrate in situ in isolated lungs that surface tension is elevated in an acid-aspiration acute respiratory distress syndrome (ARDS) model. Following tracheal liquid instillation, also in isolated lungs, we directly sample alveolar liquid. We find that liquid instillation into normal lungs washes mucins to the alveolus, thereby raising alveolar surface tension. Furthermore, even if exogenous surfactant could be delivered mucin-free to the alveolus, exogenous surfactant might fail to normalize alveolar surface tension in acid-aspiration ARDS.
Collapse
Affiliation(s)
- Tam L Nguyen
- Department of Biomedical Engineering, Stevens Institute of Technology , Hoboken, New Jersey
| | - Carrie E Perlman
- Department of Biomedical Engineering, Stevens Institute of Technology , Hoboken, New Jersey
| |
Collapse
|
6
|
Rindler TN, Stockman CA, Filuta AL, Brown KM, Snowball JM, Zhou W, Veldhuizen R, Zink EM, Dautel SE, Clair G, Ansong C, Xu Y, Bridges JP, Whitsett JA. Alveolar injury and regeneration following deletion of ABCA3. JCI Insight 2017; 2:97381. [PMID: 29263307 PMCID: PMC5752264 DOI: 10.1172/jci.insight.97381] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 11/08/2017] [Indexed: 12/18/2022] Open
Abstract
Adaptation to air breathing after birth is dependent upon the synthesis and secretion of pulmonary surfactant by alveolar type 2 (AT2) cells. Surfactant, a complex mixture of phospholipids and proteins, is secreted into the alveolus, where it reduces collapsing forces at the air-liquid interface to maintain lung volumes during the ventilatory cycle. ABCA3, an ATP-dependent Walker domain containing transport protein, is required for surfactant synthesis and lung function at birth. Mutations in ABCA3 cause severe surfactant deficiency and respiratory failure in newborn infants. We conditionally deleted the Abca3 gene in AT2 cells in the mature mouse lung. Loss of ABCA3 caused alveolar cell injury and respiratory failure. ABCA3-related lung dysfunction was associated with surfactant deficiency, inflammation, and alveolar-capillary leak. Extensive but incomplete deletion of ABCA3 caused alveolar injury and inflammation, and it initiated proliferation of progenitor cells, restoring ABCA3 expression, lung structure, and function. M2-like macrophages were recruited to sites of AT2 cell proliferation during the regenerative process and were present in lung tissue from patients with severe lung disease caused by mutations in ABCA3. The remarkable and selective regeneration of ABCA3-sufficient AT2 progenitor cells provides plausible approaches for future correction of ABCA3 and other genetic disorders associated with surfactant deficiency and acute interstitial lung disease.
Collapse
Affiliation(s)
- Tara N. Rindler
- Perinatal Institute, Cincinnati Children’s Hospital Medical Center, Division of Neonatology, Perinatal and Pulmonary Biology, Cincinnati, Ohio, USA
| | - Courtney A. Stockman
- Perinatal Institute, Cincinnati Children’s Hospital Medical Center, Division of Neonatology, Perinatal and Pulmonary Biology, Cincinnati, Ohio, USA
| | - Alyssa L. Filuta
- Perinatal Institute, Cincinnati Children’s Hospital Medical Center, Division of Neonatology, Perinatal and Pulmonary Biology, Cincinnati, Ohio, USA
| | - Kari M. Brown
- Perinatal Institute, Cincinnati Children’s Hospital Medical Center, Division of Neonatology, Perinatal and Pulmonary Biology, Cincinnati, Ohio, USA
| | - John M. Snowball
- Perinatal Institute, Cincinnati Children’s Hospital Medical Center, Division of Neonatology, Perinatal and Pulmonary Biology, Cincinnati, Ohio, USA
| | - Wenjia Zhou
- Lawson Health Research Institute, Departments of Physiology and Pharmacology, Medicine, Western University, London, Ontario, Canada
| | - Ruud Veldhuizen
- Lawson Health Research Institute, Departments of Physiology and Pharmacology, Medicine, Western University, London, Ontario, Canada
| | - Erika M. Zink
- Biological Science Division, Pacific Northwest National Laboratory (PNNL), Richland, Washington, USA
| | - Sydney E. Dautel
- Biological Science Division, Pacific Northwest National Laboratory (PNNL), Richland, Washington, USA
| | - Geremy Clair
- Biological Science Division, Pacific Northwest National Laboratory (PNNL), Richland, Washington, USA
| | - Charles Ansong
- Biological Science Division, Pacific Northwest National Laboratory (PNNL), Richland, Washington, USA
| | - Yan Xu
- Perinatal Institute, Cincinnati Children’s Hospital Medical Center, Division of Neonatology, Perinatal and Pulmonary Biology, Cincinnati, Ohio, USA
| | - James P. Bridges
- Perinatal Institute, Cincinnati Children’s Hospital Medical Center, Division of Neonatology, Perinatal and Pulmonary Biology, Cincinnati, Ohio, USA
| | - Jeffrey A. Whitsett
- Perinatal Institute, Cincinnati Children’s Hospital Medical Center, Division of Neonatology, Perinatal and Pulmonary Biology, Cincinnati, Ohio, USA
| |
Collapse
|
7
|
Schwingshackl A, Lopez B, Teng B, Luellen C, Lesage F, Belperio J, Olcese R, Waters CM. Hyperoxia treatment of TREK-1/TREK-2/TRAAK-deficient mice is associated with a reduction in surfactant proteins. Am J Physiol Lung Cell Mol Physiol 2017; 313:L1030-L1046. [PMID: 28839101 DOI: 10.1152/ajplung.00121.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 08/15/2017] [Accepted: 08/16/2017] [Indexed: 12/29/2022] Open
Abstract
We previously proposed a role for the two-pore domain potassium (K2P) channel TREK-1 in hyperoxia (HO)-induced lung injury. To determine whether redundancy among the three TREK isoforms (TREK-1, TREK-2, and TRAAK) could protect from HO-induced injury, we now examined the effect of deletion of all three TREK isoforms in a clinically relevant scenario of prolonged HO exposure and mechanical ventilation (MV). We exposed WT and TREK-1/TREK-2/TRAAK-deficient [triple knockout (KO)] mice to either room air, 72-h HO, MV [high and low tidal volume (TV)], or a combination of HO + MV and measured quasistatic lung compliance, bronchoalveolar lavage (BAL) protein concentration, histologic lung injury scores (LIS), cellular apoptosis, and cytokine levels. We determined surfactant gene and protein expression and attempted to prevent HO-induced lung injury by prophylactically administering an exogenous surfactant (Curosurf). HO treatment increased lung injury in triple KO but not WT mice, including an elevated LIS, BAL protein concentration, and markers of apoptosis, decreased lung compliance, and a more proinflammatory cytokine phenotype. MV alone had no effect on lung injury markers. Exposure to HO + MV (low TV) further decreased lung compliance in triple KO but not WT mice, and HO + MV (high TV) was lethal for triple KO mice. In triple KO mice, the HO-induced lung injury was associated with decreased surfactant protein (SP) A and SPC but not SPB and SPD expression. However, these changes could not be explained by alterations in the transcription factors nuclear factor-1 (NF-1), NKX2.1/thyroid transcription factor-1 (TTF-1) or c-jun, or lamellar body levels. Prophylactic Curosurf administration did not improve lung injury scores or compliance in triple KO mice.
Collapse
Affiliation(s)
| | - Benjamin Lopez
- Department of Pediatrics, University of California, Los Angeles, California
| | - Bin Teng
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Charlean Luellen
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee; and
| | - Florian Lesage
- Université Côte d'Azur, Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Laboratory of Excellence "Ion Channel Science and Therapeutics," Valbonne, France
| | - John Belperio
- Department of Pulmonary and Critical Care, University of California, Los Angeles, California
| | - Riccardo Olcese
- Department of Anesthesiology and Perioperative Medicine, University of California, Los Angeles, California
| | - Christopher M Waters
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee; and
| |
Collapse
|
8
|
Wu Y, Nguyen TL, Perlman CE. Accelerated deflation promotes homogeneous airspace liquid distribution in the edematous lung. J Appl Physiol (1985) 2016; 122:739-751. [PMID: 27979983 DOI: 10.1152/japplphysiol.00526.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 12/07/2016] [Accepted: 12/08/2016] [Indexed: 11/22/2022] Open
Abstract
Edematous lungs contain regions with heterogeneous alveolar flooding. Liquid is trapped in flooded alveoli by a pressure barrier-higher liquid pressure at the border than in the center of flooded alveoli-that is proportional to surface tension, T Stress is concentrated between aerated and flooded alveoli, to a degree proportional to T Mechanical ventilation, by cyclically increasing T, injuriously exacerbates stress concentrations. Overcoming the pressure barrier to redistribute liquid more homogeneously between alveoli should reduce stress concentration prevalence and ventilation injury. In isolated rat lungs, we test whether accelerated deflation can overcome the pressure barrier and catapult liquid out of flooded alveoli. We generate a local edema model with normal T by microinfusing liquid into surface alveoli. We generate a global edema model with high T by establishing hydrostatic edema, which does not alter T, and then gently ventilating the edematous lungs, which increases T at 15 cmH2O transpulmonary pressure by 52%. Thus ventilation of globally edematous lungs increases T, which should increase stress concentrations and, with positive feedback, cause escalating ventilation injury. In the local model, when the pressure barrier is moderate, accelerated deflation causes liquid to escape from flooded alveoli and redistribute more equitably. Flooding heterogeneity tends to decrease. In the global model, accelerated deflation causes liquid escape, but-because of elevated T-the liquid jumps to nearby, aerated alveoli. Flooding heterogeneity is unaltered. In pulmonary edema with normal T, early ventilation with accelerated deflation might reduce the positive feedback mechanism through which ventilation injury increases over time.NEW & NOTEWORTHY We introduce, in the isolated rat lung, a new model of pulmonary edema with elevated surface tension. We first generate hydrostatic edema and then ventilate gently to increase surface tension. We investigate the mechanical mechanisms through which 1) ventilation injures edematous lungs and 2) ventilation with accelerated deflation might lessen ventilation injury.
Collapse
Affiliation(s)
- You Wu
- Biomedical Engineering, Chemistry and Biological Sciences, Stevens Institute of Technology, Hoboken, New Jersey
| | - Tam L Nguyen
- Biomedical Engineering, Chemistry and Biological Sciences, Stevens Institute of Technology, Hoboken, New Jersey
| | - Carrie E Perlman
- Biomedical Engineering, Chemistry and Biological Sciences, Stevens Institute of Technology, Hoboken, New Jersey
| |
Collapse
|
9
|
The effect of diet-induced serum hypercholesterolemia on the surfactant system and the development of lung injury. Biochem Biophys Rep 2016; 7:180-187. [PMID: 28758151 PMCID: PMC5527759 DOI: 10.1016/j.bbrep.2016.06.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a pulmonary disorder associated with alterations to the pulmonary surfactant system. Recent studies showed that supra-physiological levels of cholesterol in surfactant contribute to impaired function. Since cholesterol is incorporated into surfactant within the alveolar type II cells which derives its cholesterol from serum, it was hypothesized that serum hypercholesterolemia would predispose the host to the development of lung injury due to alterations of cholesterol content in the surfactant system. Wistar rats were randomized to a standard lab diet or a high cholesterol diet for 17–20 days. Animals were then exposed to one of three models of lung injury: i) acid aspiration ii) ventilation induced lung injury, and iii) surfactant depletion. Following physiological monitoring, lungs were lavaged to obtain and analyze the surfactant system. The physiological results showed there was no effect of the high cholesterol diet on the severity of lung injury in any of the three models of injury. There was also no effect of the diet on surfactant cholesterol composition. Rats fed a high cholesterol diet had a significant impairment in surface tension reducing capabilities of isolated surfactant compared to those fed a standard diet exposed to the surfactant depletion injury. In addition, only rats that were exposed to ventilation induced lung injury had elevated levels of surfactant associated cholesterol compared to non-injured rats. It is concluded that serum hypercholesterolemia does not predispose rats to altered surfactant cholesterol composition or to lung injury. Elevated cholesterol within surfactant may be a marker for ventilation induced lung damage. Hypercholesterolemia in rats did not alter the susceptibility to lung injury. Elevated cholesterol within surfactant is observed in ventilation induced lung injury. Increases in surfactant-associated cholesterol depend on the type of lung injury.
Collapse
|
10
|
Willson DF, Truwit JD, Conaway MR, Traul CS, Egan EE. The Adult Calfactant in Acute Respiratory Distress Syndrome Trial. Chest 2015; 148:356-364. [DOI: 10.1378/chest.14-1139] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
|
11
|
Lin S, Ikegami M, Moon C, Naren AP, Shannon JM. Lysophosphatidylcholine Acyltransferase 1 (LPCAT1) Specifically Interacts with Phospholipid Transfer Protein StarD10 to Facilitate Surfactant Phospholipid Trafficking in Alveolar Type II Cells. J Biol Chem 2015; 290:18559-74. [PMID: 26048993 DOI: 10.1074/jbc.m115.666701] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Indexed: 01/10/2023] Open
Abstract
Pulmonary surfactant, a mixture of proteins and phospholipids, plays an important role in facilitating gas exchange by maintaining alveolar stability. Saturated phosphatidylcholine (SatPC), the major component of surfactant, is synthesized both de novo and by the remodeling of unsaturated phosphatidylcholine (PC) by lyso-PC acyltransferase 1 (LPCAT1). After synthesis in the endoplasmic reticulum, SatPC is routed to lamellar bodies (LBs) for storage prior to secretion. The mechanism by which SatPC is transported to LB is not understood. The specificity of LPCAT1 for lyso-PC as an acyl acceptor suggests that formation of SatPC via LPCAT1 reacylation is a final step in SatPC synthesis prior to transport. We hypothesized that LPCAT1 forms a transient complex with SatPC and specific phospholipid transport protein(s) to initiate trafficking of SatPC from the endoplasmic reticulum to the LB. Herein we have assessed the ability of different StarD proteins to interact with LPCAT1. We found that LPCAT1 interacts with StarD10, that this interaction is direct, and that amino acids 79-271 of LPCAT1 and the steroidogenic acute regulatory protein-related lipid transfer (START) domain of START domain-containing protein 10 (StarD10) are sufficient for this interaction. The role of StarD10 in trafficking of phospholipid to LB was confirmed by the observation that knockdown of StarD10 significantly reduced transport of phospholipid to LB. LPCAT1 also interacted with one isoform of StarD7 but showed no interaction with StarD2/PC transfer protein.
Collapse
Affiliation(s)
- Sui Lin
- From the Divisions of Pulmonary Biology and
| | | | - Changsuk Moon
- Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Anjaparavanda P Naren
- Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | | |
Collapse
|
12
|
Zambelli V, Bellani G, Amigoni M, Grassi A, Scanziani M, Farina F, Latini R, Pesenti A. The effects of exogenous surfactant treatment in a murine model of two-hit lung injury. Anesth Analg 2015; 120:381-8. [PMID: 25502842 DOI: 10.1213/ane.0000000000000549] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Because pulmonary endogenous surfactant is altered during acute respiratory distress syndrome, surfactant replacement may improve clinical outcomes. However, trials of surfactant use have had mixed results. We designed this animal model of unilateral (right) lung injury to explore the effect of exogenous surfactant administered to the injured lung on inflammation in the injured and noninjured lung. METHODS Mice underwent hydrochloric acid instillation (1.5 mL/kg) into the right bronchus and prolonged (7 hours) mechanical ventilation (25 mL/kg). After 3 hours, mice were treated with 1 mL/kg exogenous surfactant (Curosurf®) (surf group) or sterile saline (NaCl 0.9%) (vehicle group) in the injured (right) lung or did not receive any treatment (hydrochloric acid, ventilator-induced lung injury). Gas exchange, lung compliance, and bronchoalveolar inflammation (cells, albumin, and cytokines) were evaluated. After a significant analysis of variance (ANOVA) test, Tukey post hoc test was used for statistical analysis. RESULTS At least 8 to 10 mice in each group were analyzed for each evaluated variable. Surfactant treatment significantly increased both the arterial oxygen tension to fraction of inspired oxygen ratio and respiratory system static compliance (P = 0.027 and P = 0.007, respectively, for surf group versus vehicle). Surfactant therapy increased indices of inflammation in the acid-injured lung compared with vehicle: inflammatory cells (685 [602-773] and 216 [125-305] × 1000/mL, respectively; P < 0.001) and albumin in bronchoalveolar lavage (BAL) (1442 ± 588 and 743 ± 647 μg/mL, respectively; P = 0.027). These differences were not found (P = 0.96 and P = 0.54) in the contralateral (uninjured) lung (inflammatory cells 131 [78-195] and 119 [87-149] × 1000/mL and albumin 135 ± 100 and 173 ± 115 μg/mL). CONCLUSIONS Exogenous surfactant administration to an acid-injured right lung improved gas exchange and whole respiratory system compliance. However, markers of inflammation increased in the right (injured) lung, although this result was not found in the left (uninjured) lung. These data suggest that the mechanism by which surfactant improves lung function may involve both uninjured and injured alveoli.
Collapse
Affiliation(s)
- Vanessa Zambelli
- From the *Department of Health Science, University of Milano-Bicocca, Monza, Italy; †Department of Emergency, San Gerardo Hospital, Monza, Italy; and ‡Department of Cardiovascular Research, Istituto di Ricerche Farmacologiche, Milano, Italy
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Rimensberger PC. Surfactant. PEDIATRIC AND NEONATAL MECHANICAL VENTILATION 2015. [PMCID: PMC7175631 DOI: 10.1007/978-3-642-01219-8_28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Exogenous pulmonary surfactant, widely used in neonatal care, is one of the best-studied treatments in neonatology, and its introduction in the 1990s led to a significant improvement in neonatal outcomes in preterm infants, including a decrease in mortality. This chapter provides an overview of surfactant composition and function in health and disease and summarizes the evidence for its clinical use.
Collapse
Affiliation(s)
- Peter C. Rimensberger
- Service of Neonatology and Pediatric Intensive Care, Department of Pediatrics, University Hospital of Geneva, Geneve, Switzerland
| |
Collapse
|
14
|
Agarwal AR, Yin F, Cadenas E. Short-term cigarette smoke exposure leads to metabolic alterations in lung alveolar cells. Am J Respir Cell Mol Biol 2014; 51:284-93. [PMID: 24625219 DOI: 10.1165/rcmb.2013-0523oc] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Cigarette smoke (CS)-induced alveolar destruction and energy metabolism changes are known contributors to the pathophysiology of chronic obstructive pulmonary disease (COPD). This study examines the effect of CS exposure on metabolism in alveolar type II cells. Male A/J mice (8 wk old) were exposed to CS generated from a smoking machine for 4 or 8 weeks, and a recovery group was exposed to CS for 8 weeks and allowed to recover for 2 weeks. Alveolar type II cells were isolated from air- or CS- exposed mice. Acute CS exposure led to a reversible airspace enlargement in A/J mice as measured by the increase in mean linear intercept, indicative of alveolar destruction. The effect of CS exposure on cellular respiration was studied using the XF Extracellular Flux Analyzer. A decrease in respiration while metabolizing glucose was observed in the CS-exposed group, indicating altered glycolysis that was compensated by an increase in palmitate utilization; palmitate utilization was accompanied by an increase in the expression of CD36 and carnitine-palmitoyl transferase 1 in type II alveolar cells for the transport of palmitate into the cells and into mitochondria, respectively. The increase in palmitate use for energy production likely affects the surfactant biosynthesis pathway, as evidenced by the decrease in phosphatidylcholine levels and the increase in phospholipase A2 activity after CS exposure. These findings help our understanding of the mechanism underlying the surfactant deficiency observed in smokers and provide a target to delay the onset of COPD.
Collapse
Affiliation(s)
- Amit R Agarwal
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California
| | | | | |
Collapse
|
15
|
Wu Y, Kharge AB, Perlman CE. Lung ventilation injures areas with discrete alveolar flooding, in a surface tension-dependent fashion. J Appl Physiol (1985) 2014; 117:788-96. [PMID: 25080924 DOI: 10.1152/japplphysiol.00569.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
With proteinaceous-liquid flooding of discrete alveoli, a model of the edema pattern in the acute respiratory distress syndrome, lung inflation over expands aerated alveoli adjacent to flooded alveoli. Theoretical considerations suggest that the overexpansion may be proportional to surface tension, T. Yet recent evidence indicates proteinaceous edema liquid may not elevate T. Thus whether the overexpansion is injurious is not known. Here, working in the isolated, perfused rat lung, we quantify fluorescence movement from the vasculature to the alveolar liquid phase as a measure of overdistension injury to the alveolar-capillary barrier. We label the perfusate with fluorescence; micropuncture a surface alveolus and instill a controlled volume of nonfluorescent liquid to obtain a micropunctured-but-aerated region (control group) or a region with discrete alveolar flooding; image the region at a constant transpulmonary pressure of 5 cmH2O; apply five ventilation cycles with a positive end-expiratory pressure of 0-20 cmH2O and tidal volume of 6 or 12 ml/kg; return the lung to a constant transpulmonary pressure of 5 cmH2O; and image for an additional 10 min. In aerated areas, ventilation is not injurious. With discrete alveolar flooding, all ventilation protocols cause sustained injury. Greater positive end-expiratory pressure or tidal volume increases injury. Furthermore, we determine T and find injury increases with T. Inclusion of either plasma proteins or Survanta in the flooding liquid does not alter T or injury. Inclusion of 2.7-10% albumin and 1% Survanta together, however, lowers T and injury. Contrary to expectation, albumin inclusion in our model facilitates exogenous surfactant activity.
Collapse
Affiliation(s)
- You Wu
- Chemistry, Chemical Biology & Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey
| | - Angana Banerjee Kharge
- Chemistry, Chemical Biology & Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey
| | - Carrie E Perlman
- Chemistry, Chemical Biology & Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey
| |
Collapse
|
16
|
Kharge AB, Wu Y, Perlman CE. Surface tension in situ in flooded alveolus unaltered by albumin. J Appl Physiol (1985) 2014; 117:440-51. [PMID: 24970853 DOI: 10.1152/japplphysiol.00084.2014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the acute respiratory distress syndrome, plasma proteins in alveolar edema liquid are thought to inactivate lung surfactant and raise surface tension, T. However, plasma protein-surfactant interaction has been assessed only in vitro, during unphysiologically large surface area compression (%ΔA). Here, we investigate whether plasma proteins raise T in situ in the isolated rat lung under physiologic conditions. We flood alveoli with liquid that omits/includes plasma proteins. We ventilate the lung between transpulmonary pressures of 5 and 15 cmH2O to apply a near-maximal physiologic %ΔA, comparable to that of severe mechanical ventilation, or between 1 and 30 cmH2O, to apply a supraphysiologic %ΔA. We pause ventilation for 20 min and determine T at the meniscus that is present at the flooded alveolar mouth. We determine alveolar air pressure at the trachea, alveolar liquid phase pressure by servo-nulling pressure measurement, and meniscus radius by confocal microscopy, and we calculate T according to the Laplace relation. Over 60 ventilation cycles, application of maximal physiologic %ΔA to alveoli flooded with 4.6% albumin solution does not alter T; supraphysiologic %ΔA raise T, transiently, by 51 ± 4%. In separate experiments, we find that addition of exogenous surfactant to the alveolar liquid can, with two cycles of maximal physiologic %ΔA, reduce T by 29 ± 11% despite the presence of albumin. We interpret that supraphysiologic %ΔA likely collapses the interfacial surfactant monolayer, allowing albumin to raise T. With maximal physiologic %ΔA, the monolayer likely remains intact such that albumin, blocked from the interface, cannot interfere with native or exogenous surfactant activity.
Collapse
Affiliation(s)
- Angana Banerjee Kharge
- Department of Chemistry, Chemical Biology & Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey
| | - You Wu
- Department of Chemistry, Chemical Biology & Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey
| | - Carrie E Perlman
- Department of Chemistry, Chemical Biology & Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey
| |
Collapse
|
17
|
Kurabe N, Hayasaka T, Igarashi H, Mori H, Sekihara K, Tao H, Yamada H, Kahyo T, Onishi I, Tsukui H, Kawase A, Matsuura S, Inoue Y, Shinmura K, Funai K, Setou M, Sugimura H. Visualization of phosphatidylcholine (16:0/16:0) in type II alveolar epithelial cells in the human lung using imaging mass spectrometry. Pathol Int 2013; 63:195-200. [PMID: 23692419 DOI: 10.1111/pin.12050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 04/03/2013] [Indexed: 12/22/2022]
Abstract
Imaging mass spectrometry (MS) is an emerging technique that can detect numerous biomolecular distributions in a non-targeting manner. In the present study, we applied a mass imaging modality, mass microscopy, to human lung tissue and identified several molecules including surfactant constituents in a specific structure of the lung alveoli. Four peaks were identified using imaging MS, and the ion at m/z 772.5, in particular, was localized at some spots in the alveolar walls. Using an MS/MS analysis, the ion was identified as phosphatidylcholine (PC)(16:0/16:0), which is the main component of lung surfactant. In a larger magnification of the lung specimen, PC (16:0/16:0) was distributed in a mottled fashion in a section of the lung. Importantly, the distribution of PC (16:0/16:0) was identical to that of anti-SLC34A2 antibody immunoreactivity, which is known to be a specific marker of type II alveolar epithelial cells, in the same section. Our experience suggests that imaging MS has excellent potential in human pathology research.
Collapse
Affiliation(s)
- Nobuya Kurabe
- Department of Tumor Pathology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka 431-3192, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Abstract
This article describes the gas exchange abnormalities occurring in the acute respiratory distress syndrome seen in adults and children and in the respiratory distress syndrome that occurs in neonates. Evidence is presented indicating that the major gas exchange abnormality accounting for the hypoxemia in both conditions is shunt, and that approximately 50% of patients also have lungs regions in which low ventilation-to-perfusion ratios contribute to the venous admixture. The various mechanisms by which hypercarbia may develop and by which positive end-expiratory pressure improves gas exchange are reviewed, as are the effects of vascular tone and airway narrowing. The mechanisms by which surfactant abnormalities occur in the two conditions are described, as are the histological findings that have been associated with shunt and low ventilation-to-perfusion.
Collapse
Affiliation(s)
- Richard K Albert
- Chief of Medicine, Denver Health, Professor of Medicine, University of Colorado, Adjunct Professor of Engineering and Computer Science, University of Denver, Denver, Colorado, USA.
| | | |
Collapse
|
19
|
Abstract
Mechanical ventilation (MV) is, by definition, the application of external forces to the lungs. Depending on their magnitude, these forces can cause a continuum of pathophysiological alterations ranging from the stimulation of inflammation to the disruption of cell-cell contacts and cell membranes. These side effects of MV are particularly relevant for patients with inhomogeneously injured lungs such as in acute lung injury (ALI). These patients require supraphysiological ventilation pressures to guarantee even the most modest gas exchange. In this situation, ventilation causes additional strain by overdistension of the yet non-injured region, and additional stress that forms because of the interdependence between intact and atelectatic areas. Cells are equipped with elaborate mechanotransduction machineries that respond to strain and stress by the activation of inflammation and repair mechanisms. Inflammation is the fundamental response of the host to external assaults, be they of mechanical or of microbial origin and can, if excessive, injure the parenchymal tissue leading to ALI. Here, we will discuss the forces generated by MV and how they may injure the lungs mechanically and through inflammation. We will give an overview of the mechanotransduction and how it leads to inflammation and review studies demonstrating that ventilator-induced lung injury can be prevented by blocking pathways of mechanotransduction or inflammation.
Collapse
Affiliation(s)
- Ulrike Uhlig
- Department of Pharmacology & Toxicology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | | |
Collapse
|
20
|
Czernik C, Schmalisch G, Bührer C, Proquitté H. Fetal and neonatal samples of a precursor surfactant protein B inversely related to gestational age. BMC Pediatr 2013; 13:164. [PMID: 24112641 PMCID: PMC3852371 DOI: 10.1186/1471-2431-13-164] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 10/08/2013] [Indexed: 11/12/2022] Open
Abstract
Background Alveolar–capillary membrane leaks can increase the amount of surfactant protein B (SP-B) in the bloodstream. The purpose of this study was to measure the concentration of C-proSP-B, a SP-B precursor that includes C-terminal domains, in various body fluids of newborn infants and determine its dependence on gestational age. Methods C-pro-SPB was measured in amniotic fluid and umbilical cord blood at birth, and in peripheral blood and urine on postnatal day 3 in 137 newborn infants with a median birth weight of 2015 g (range, 550–4475 g) and gestational age of 34 weeks (range, 23–42 weeks). Results C-proSP-B levels differed more than 100-fold among samples. The levels (median; interquartile range) were highest in peripheral blood (655.6 ng/mL; 419.0-1467.0 ng/mL) and lowest in urine (3.08 ng/mL; 2.96-3.35 ng/mL). C-proSP-B levels in amniotic fluid (314.9 ng/mL; 192.7–603.6 ng/mL) were approximately half of those in peripheral blood. In cord blood C-proSP-B was slightly lower (589.1 ng/mL; 181.2-1129.0 ng/mL) compared with peripheral blood. C-proSP-B levels significantly increased in all the fluids sampled except urine with decreasing gestational age (p < 0.001). Conclusions This novel assay allows for the quantitative measurement of C-proSP-B in blood and amniotic fluid. The dependence of C-proSP-B on gestational age may hamper its use for the detection of alveolar leaks in preterm newborns.
Collapse
Affiliation(s)
- Christoph Czernik
- Department of Neonatology, Charité University Medical Center, Berlin, Germany.
| | | | | | | |
Collapse
|
21
|
Abstract
RATIONALE Our previous studies in children with acute lung injury/acute respiratory distress syndrome demonstrated improved outcomes with exogenous surfactant (calfactant) administration. Sample sizes in those studies were small, however, and the subject populations heterogeneous, thus making recommendations tenuous. OBJECTIVE To investigate the efficacy of surfactant administration in a larger, more homogenous population of children with lung injury/acute respiratory distress syndrome due to direct lung injury. DESIGN AND SETTING Masked, randomized, placebo-controlled trial in 24 children's hospitals in six different countries. PATIENTS AND METHODS Children 37 weeks postconception to 18 years old with lung injury/acute respiratory distress syndrome due to direct lung injury were randomized to receive up to three doses of 30 mg/cm height of surfactant (calfactant) versus placebo (air) within 48 hours of intubation and initiation of mechanical ventilation. The primary outcome was mortality at 90 days. Ventilator-free days, changes in oxygenation, and adverse events were also assessed. RESULTS The study was stopped at the sponsor's request after the second interim analysis for presumed futility. A total of 110 subjects were enrolled, with consent withdrawn from one whose data are unavailable. There were no significant differences between groups except in hospital-free days (10.4 ± 7.8 placebo vs 6.4 ± 7.8 surfactant; p = 0.01). Overall 90-day mortality was 11% (seven surfactant, five placebo). No immediate improvement in oxygenation was associated with surfactant administration. CONCLUSIONS Surfactant did not improve outcomes relative to placebo in this trial of children with direct lung injury/acute respiratory distress syndrome. Differences in concentration of the surfactant, failure to recruit the lung during surfactant administration, or using two rather than four position changes during administration are possible explanations for the difference from previous studies. Exogenous surfactant cannot be recommended at this time for children with direct lung injury/acute respiratory distress syndrome.
Collapse
|
22
|
Dushianthan A, Cusack R, Goss V, Postle AD, Grocott MPW. Clinical review: Exogenous surfactant therapy for acute lung injury/acute respiratory distress syndrome--where do we go from here? Crit Care 2012; 16:238. [PMID: 23171712 PMCID: PMC3672556 DOI: 10.1186/cc11512] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Acute lung injury and acute respiratory distress syndrome (ARDS) are characterised by severe hypoxemic respiratory failure and poor lung compliance. Despite advances in clinical management, morbidity and mortality remains high. Supportive measures including protective lung ventilation confer a survival advantage in patients with ARDS, but management is otherwise limited by the lack of effective pharmacological therapies. Surfactant dysfunction with quantitative and qualitative abnormalities of both phospholipids and proteins are characteristic of patients with ARDS. Exogenous surfactant replacement in animal models of ARDS and neonatal respiratory distress syndrome shows consistent improvements in gas exchange and survival. However, whilst some adult studies have shown improved oxygenation, no survival benefit has been demonstrated to date. This lack of clinical efficacy may be related to disease heterogeneity (where treatment responders may be obscured by nonresponders), limited understanding of surfactant biology in patients or an absence of therapeutic effect in this population. Crucially, the mechanism of lung injury in neonates is different from that in ARDS: surfactant inhibition by plasma constituents is a typical feature of ARDS, whereas the primary pathology in neonates is the deficiency of surfactant material due to reduced synthesis. Absence of phenotypic characterisation of patients, the lack of an ideal natural surfactant material with adequate surfactant proteins, coupled with uncertainty about optimal timing, dosing and delivery method are some of the limitations of published surfactant replacement clinical trials. Recent advances in stable isotope labelling of surfactant phospholipids coupled with analytical methods using electrospray ionisation mass spectrometry enable highly specific molecular assessment of phospholipid subclasses and synthetic rates that can be utilised for phenotypic characterisation and individualisation of exogenous surfactant replacement therapy. Exploring the clinical benefit of such an approach should be a priority for future ARDS research.
Collapse
Affiliation(s)
- Ahilanandan Dushianthan
- Anaesthesia and Critical Care Research Unit, CE 93, MP24, E-Level, Centre Block, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
- Integrative Physiology and Critical Illness, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
| | - Rebecca Cusack
- Anaesthesia and Critical Care Research Unit, CE 93, MP24, E-Level, Centre Block, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
| | - Victoria Goss
- Integrative Physiology and Critical Illness, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
| | - Anthony D Postle
- Integrative Physiology and Critical Illness, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
| | - Mike PW Grocott
- Anaesthesia and Critical Care Research Unit, CE 93, MP24, E-Level, Centre Block, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
- Integrative Physiology and Critical Illness, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
| |
Collapse
|
23
|
Machado-Aranda D, Wang Z, Yu B, Suresh MV, Notter RH, Raghavendran K. Increased phospholipase A2 and lyso-phosphatidylcholine levels are associated with surfactant dysfunction in lung contusion injury in mice. Surgery 2012; 153:25-35. [PMID: 22853859 DOI: 10.1016/j.surg.2012.05.043] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 05/21/2012] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Surfactant dysfunction is an important pathologic disturbance in various forms of acute inflammatory lung injury. Previously we reported the presence of marked alterations in the composition and activity of pulmonary surfactant in bilateral lung contusions (LC) injury induced by blunt trauma in rats. This is extended here to a mouse model of unilateral LC with a focus on compositional and functional changes in surfactant associated with permeability injury and increases in activity of secretory phospholipase A2. RESULTS Surfactant-associated gene expression was not altered in mice with unilateral LC injury on the basis of Affymetrix analysis. LC mice had significant permeability injury with increased albumin and total protein in bronchoalveolar lavage at 5, 24, 48, and 72 hours after insult compared with uninjured controls. The percent content of large surfactant aggregates was depleted at all postinjury times, and pulmonary pressure-volume (P-V) mechanics and compliance were abnormal during this period. Surfactant dysfunction was evaluated in 24 hours, when permeability injury and P-V changes were most prominent. At this time, activity levels of secretory phospholipase A2 were increased in bronchoalveolar lavage, and chromatographic analysis showed that large surfactant aggregates had decreased levels of phosphatidylcholine and increased levels of lyso-phosphatidylcholine. These changes were accompanied by severe detriments in large aggregate surface activity by pulsating bubble surfactometry. Large aggregates from LC mice at 24 hours had minimum surface tensions of only 12.6 ± 1.1 mN/m after prolonged bubble pulsation (20 min) compared with 0.7 ± 0.03 mN/m for uninjured controls. CONCLUSION These results document important detriments in the composition and activity of pulmonary surfactant in LC injury in mice and suggest that active synthetic phospholipase-resistant exogenous surfactants may have utility in treating surfactant dysfunction in this clinically important condition.
Collapse
|
24
|
Raghavendran K, Willson D, Notter RH. Surfactant therapy for acute lung injury and acute respiratory distress syndrome. Crit Care Clin 2011; 27:525-59. [PMID: 21742216 DOI: 10.1016/j.ccc.2011.04.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
This article examines exogenous lung surfactant replacement therapy and its usefulness in mitigating clinical acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS). Surfactant therapy is beneficial in term infants with pneumonia and meconium aspiration lung injury, and in children up to age 21 years with direct pulmonary forms of ALI/ARDS. However, extension of exogenous surfactant therapy to adults with respiratory failure and clinical ALI/ARDS remains a challenge. This article reviews clinical studies of surfactant therapy in pediatric and adult patients with ALI/ARDS, focusing on its potential advantages in patients with direct pulmonary forms of these syndromes.
Collapse
Affiliation(s)
- Krishnan Raghavendran
- Division of Acute Care Surgery, Department of Surgery, University of Michigan Health System, 1500 East Medical Center Drive, 1C340A-UH, SPC 5033, Ann Arbor, MI 48109-5033, USA.
| | | | | |
Collapse
|
25
|
Dohm MT, Brown NJ, Seurynck-Servoss SL, de la Serna JB, Barron AE. Mimicking SP-C palmitoylation on a peptoid-based SP-B analogue markedly improves surface activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:1663-78. [DOI: 10.1016/j.bbamem.2010.04.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 04/20/2010] [Accepted: 04/26/2010] [Indexed: 02/01/2023]
|
26
|
Dry powder aerosolization of a recombinant surfactant protein-C–based surfactant for inhalative treatment of the acutely inflamed lung*. Crit Care Med 2010; 38:1584-91. [DOI: 10.1097/ccm.0b013e3181dfcb3b] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
27
|
Dohm MT, Mowery BP, Czyzewski AM, Stahl SS, Gellman SH, Barron AE. Biophysical mimicry of lung surfactant protein B by random nylon-3 copolymers. J Am Chem Soc 2010; 132:7957-67. [PMID: 20481635 PMCID: PMC2981085 DOI: 10.1021/ja909734n] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Non-natural oligomers have recently shown promise as functional analogues of lung surfactant proteins B and C (SP-B and SP-C), two helical and amphiphilic proteins that are critical for normal respiration. The generation of non-natural mimics of SP-B and SP-C has previously been restricted to step-by-step, sequence-specific synthesis, which results in discrete oligomers that are intended to manifest specific structural attributes. Here we present an alternative approach to SP-B mimicry that is based on sequence-random copolymers containing cationic and lipophilic subunits. These materials, members of the nylon-3 family, are prepared by ring-opening polymerization of beta-lactams. The best of the nylon-3 polymers display promising in vitro surfactant activities in a mixed lipid film. Pulsating bubble surfactometry data indicate that films containing the most surface-active polymers attain adsorptive and dynamic-cycling properties that surpass those of discrete peptides intended to mimic SP-B. Attachment of an N-terminal octadecanoyl unit to the nylon-3 copolymers, inspired by the post-translational modifications found in SP-C, affords further improvements by reducing the percent surface area compression to reach low minimum surface tension. Cytotoxic effects of the copolymers are diminished relative to that of an SP-B-derived peptide and a peptoid-based mimic. The current study provides evidence that sequence-random copolymers can mimic the in vitro surface-active behavior of lung surfactant proteins in a mixed lipid film. These findings raise the possibility that random copolymers might be useful for developing a lung surfactant replacement, which is an attractive prospect given that such polymers are easier to prepare than are sequence-specific oligomers.
Collapse
Affiliation(s)
- Michelle T. Dohm
- Department of Chemistry, Northwestern University, 2145 N. Sheridan Rd., Evanston, Illinois 60208-3100
| | - Brendan P. Mowery
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin, 53706
| | - Ann M. Czyzewski
- Department of Chemical and Biological Engineering, Northwestern University, 2145 N. Sheridan Rd., Evanston, Illinois 60208-3100
| | - Shannon S. Stahl
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin, 53706
| | - Samuel H. Gellman
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin, 53706
| | - Annelise E. Barron
- Department of Chemical and Biological Engineering, Northwestern University, 2145 N. Sheridan Rd., Evanston, Illinois 60208-3100
- Department of Bioengineering, Stanford University, W300B James H. Clark Center, 318 Campus Drive, Stanford, California 94305-5440
| |
Collapse
|
28
|
Nonventilatory strategies for patients with life-threatening 2009 H1N1 influenza and severe respiratory failure. Crit Care Med 2010; 38:e74-90. [PMID: 20035216 DOI: 10.1097/ccm.0b013e3181cc5373] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Severe respiratory failure (including acute lung injury and acute respiratory distress syndrome) caused by 2009 H1N1 influenza infection has been reported worldwide. Refractory hypoxemia is a common finding in these patients and can be challenging to manage. This review focuses on nonventilatory strategies in the advanced treatment of severe respiratory failure and refractory hypoxemia such as that seen in patients with severe acute respiratory distress syndrome attributable to 2009 H1N1 influenza. Specific modalities covered include conservative fluid management, prone positioning, inhaled nitric oxide, inhaled vasodilatory prostaglandins, and extracorporeal membrane oxygenation and life support. Pharmacologic strategies (including steroids) investigated for the treatment of severe respiratory failure are also reviewed.
Collapse
|
29
|
Bridges JP, Ikegami M, Brilli LL, Chen X, Mason RJ, Shannon JM. LPCAT1 regulates surfactant phospholipid synthesis and is required for transitioning to air breathing in mice. J Clin Invest 2010; 120:1736-48. [PMID: 20407208 DOI: 10.1172/jci38061] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 02/10/2010] [Indexed: 01/18/2023] Open
Abstract
Respiratory distress syndrome (RDS), which is the leading cause of death in premature infants, is caused by surfactant deficiency. The most critical and abundant phospholipid in pulmonary surfactant is saturated phosphatidylcholine (SatPC), which is synthesized in alveolar type II cells de novo or by the deacylation-reacylation of existing phosphatidylcholine species. We recently cloned and partially characterized a mouse enzyme with characteristics of a lung lysophosphatidylcholine acyltransferase (LPCAT1) that we predicted would be involved in surfactant synthesis. Here, we describe our studies investigating whether LPCAT1 is required for pulmonary surfactant homeostasis. To address this issue, we generated mice bearing a hypomorphic allele of Lpcat1 (referred to herein as Lpcat1GT/GT mice) using a genetrap strategy. Newborn Lpcat1GT/GT mice showed varying perinatal mortality from respiratory failure, with affected animals demonstrating hallmarks of respiratory distress such as atelectasis and hyaline membranes. Lpcat1 mRNA levels were reduced in newborn Lpcat1GT/GT mice and directly correlated with SatPC content, LPCAT1 activity, and survival. Surfactant isolated from dead Lpcat1GT/GT mice failed to reduce minimum surface tension to wild-type levels. Collectively, these data demonstrate that full LPCAT1 activity is required to achieve the levels of SatPC essential for the transition to air breathing.
Collapse
Affiliation(s)
- James P Bridges
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio45229, USA
| | | | | | | | | | | |
Collapse
|
30
|
Dohm MT, Seurynck-Servoss SL, Seo J, Zuckermann RN, Barron AE. Close mimicry of lung surfactant protein B by "clicked" dimers of helical, cationic peptoids. Biopolymers 2010; 92:538-53. [PMID: 19777571 DOI: 10.1002/bip.21309] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A family of peptoid dimers developed to mimic SP-B is presented, where two amphipathic, cationic helices are linked by an achiral octameric chain. SP-B is a vital therapeutic protein in lung surfactant replacement therapy, but its large-scale isolation or chemical synthesis is impractical. Enhanced biomimicry of SP-B's disulfide-bonded structure has been previously attempted via disulfide-mediated dimerization of SP-B(1-25) and other peptide mimics, which improved surface activity relative to the monomers. Herein, the effects of disulfide- or "click"-mediated (1,3-dipolar cycloaddition) dimerization, as well as linker chemistry, on the lipid-associated surfactant activity of a peptoid monomer are described. Results revealed that the 'clicked' peptoid dimer enhanced in vitro surface activity in a DPPC:POPG:PA lipid film relative to its disulfide-bonded and monomeric counterparts in both surface balance and pulsating bubble surfactometry studies. On the pulsating bubble surfactometer, the film containing the "clicked" peptoid dimer outperformed all presented peptoid monomers and dimers, and two SP-B derived peptides, attaining an adsorbed surface tension of 22 mN m(-1), and maximum and minimum cycling values of 42 mN m(-1) and near-zero, respectively.
Collapse
Affiliation(s)
- Michelle T Dohm
- Department of Chemistry, Northwestern University, 2145 N. Sheridan Road, Evanston, IL 60208-3100, USA
| | | | | | | | | |
Collapse
|
31
|
Marraro GA, Denaro C, Spada C, Luchetti M, Giansiracusa C. Selective medicated (saline + natural surfactant) bronchoalveolar lavage in unilateral lung contusion. A clinical randomized controlled trial. J Clin Monit Comput 2009; 24:73-81. [PMID: 20012912 DOI: 10.1007/s10877-009-9213-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 11/25/2009] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Open lung and low tidal volume ventilation appear to be a promising ventilation for chest trauma as it can reduce ARDS and improve outcome. Local therapy (e.g. BAL) can be synergic to remove from the lung the debris, mitigate inflammatory cascade and avoid damage spreading to not compromised lung areas. MATERIALS AND METHODS 44 pulmonary contused patients were randomized to receive broncho-suction and volume controlled low tidal volume ventilation-VCLTVV (Control Group) or the same ventilation plus medicated (saline + surfactant) BAL (Treatment Group). Tidal volume <10 ml/kg, PEEP of 10-12 cm H(2)O and PaO(2) 60-100 mm Hg and PaCO(2) 35-45 mm Hg were used in both groups. BAL was performed using a fiberscope. 4 boluses of 25 ml saline with 2.4 mg/ml of surfactant were introduced into each contused lobe in which, subsequently, 240 mg of surfactant was instilled. RESULTS All patients survived. In the Control Group 18 patients developed pneumonia, 5 ARDS and days of intubation were 11.50 (3.83) compared to 5.05 (1.21) of Treatment Group in which OI and PaO(2)/FiO(2) significantly improved from 36 h. CONCLUSIONS VCLTVV alone was not able to prevent ARDS and infection in the Control Group as the reduction of intubation. In the Treatment Group, VCLTVV and medicated BAL facilitated the removal of degradated lung material and recruited the contused lung regions, enabling the healing of the lung pathology.
Collapse
Affiliation(s)
- Giuseppe A Marraro
- Anesthesia and Intensive Care Department, A.O. Fatebenefratelli and Ophthalmiatric Hospital, Milan, Italy.
| | | | | | | | | |
Collapse
|
32
|
|
33
|
Xu Y, Saegusa C, Schehr A, Grant S, Whitsett JA, Ikegami M. C/EBP{alpha} is required for pulmonary cytoprotection during hyperoxia. Am J Physiol Lung Cell Mol Physiol 2009; 297:L286-98. [PMID: 19465518 DOI: 10.1152/ajplung.00094.2009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
A number of transcriptional pathways regulating fetal lung development are active during repair of the injured lung. We hypothesized that C/EBPalpha, a transcription factor critical for lung maturation, plays a role in protection of the alveolar epithelium following hyperoxic injury of the mature lung. Transgenic Cebpalpha(Delta/Delta) mice, in which Cebpalpha was conditionally deleted from Clara cells and type II cells after birth, were developed. While no pulmonary abnormalities were observed in the Cebpalpha(Delta/Delta) mice (7-8 wk old) under normal conditions, the mice were highly susceptible to hyperoxia. Cebpalpha(Delta/Delta) mice died within 4 days of exposure to 95% oxygen in association with severe lung inflammation, altered maturation of surfactant protein B and C, decreased surfactant lipid secretion, and abnormal lung mechanics at a time when all control mice survived. mRNA microarray analysis of isolated type II cells at 0, 2, and 24 h of hyperoxia demonstrated the reduced expression of number of genes regulating surfactant lipid and protein homeostasis, including Srebf, Scap, Lpcat1, Abca3, Sftpb, and Napsa. Genes influencing cell signaling or immune responses were induced in the lungs of Cebpalpha(Delta/Delta) mice. C/EBPalpha was required for the regulation of genes associated with surfactant lipid homeostasis, surfactant protein biosynthesis, processing and transport, defense response to stress, and cell redox homeostasis during exposure to hyperoxia. While C/EBPalpha did not play a critical role in postnatal pulmonary function under normal conditions, C/EBPalpha mediated protection of the lung during acute lung injury induced by hyperoxia.
Collapse
Affiliation(s)
- Yan Xu
- Cincinnati Children's Hospital Medical Center, University of Cincinnati, Ohio 45229-3039, USA
| | | | | | | | | | | |
Collapse
|
34
|
Ikegami M, Weaver TE, Grant SN, Whitsett JA. Pulmonary surfactant surface tension influences alveolar capillary shape and oxygenation. Am J Respir Cell Mol Biol 2009; 41:433-9. [PMID: 19202005 DOI: 10.1165/rcmb.2008-0359oc] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Alveolar capillaries are located in close proximity to the alveolar epithelium and beneath the surfactant film. We hypothesized that the shape of alveolar capillaries and accompanying oxygenation are influenced by surfactant surface tension in the alveolus. To prove our hypothesis, surfactant surface tension was regulated by conditional expression of surfactant protein (SP)-B in Sftpb(-/-) mice, thereby inhibiting surface tension-lowering properties of surfactant in vivo within 24 hours after depletion of Sftpb. Minimum surface tension of isolated surfactant was increased and oxygen saturation was significantly reduced after 2 days of SP-B deficiency in association with deformation of alveolar capillaries. Intravascularly injected 3.2-mum-diameter microbeads through jugular vein were retained within narrowed pulmonary capillaries after reduction of SP-B. Ultrastructure studies demonstrated that the capillary protrusion typical of the normal alveolar-capillary unit was reduced in size, consistent with altered pulmonary blood flow. Pulmonary hypertension and intrapulmonary shunting are commonly associated with surfactant deficiency and dysfunction in neonates and adults with respiratory distress syndromes. Increased surfactant surface tension caused by reduction in SP-B induced narrowing of alveolar capillaries and oxygen desaturation, demonstrating an important role of surface tension-lowering properties of surfactant in the regulation of pulmonary vascular perfusion.
Collapse
Affiliation(s)
- Machiko Ikegami
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229-3039, USA.
| | | | | | | |
Collapse
|
35
|
Christmann U, Buechner-Maxwell VA, Witonsky SG, Hite RD. Role of lung surfactant in respiratory disease: current knowledge in large animal medicine. J Vet Intern Med 2009; 23:227-42. [PMID: 19192153 DOI: 10.1111/j.1939-1676.2008.0269.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Lung surfactant is produced by type II alveolar cells as a mixture of phospholipids, surfactant proteins, and neutral lipids. Surfactant lowers alveolar surface tension and is crucial for the prevention of alveolar collapse. In addition, surfactant contributes to smaller airway patency and improves mucociliary clearance. Surfactant-specific proteins are part of the innate immune defense mechanisms of the lung. Lung surfactant alterations have been described in a number of respiratory diseases. Surfactant deficiency (quantitative deficit of surfactant) in premature animals causes neonatal respiratory distress syndrome. Surfactant dysfunction (qualitative changes in surfactant) has been implicated in the pathophysiology of acute respiratory distress syndrome and asthma. Analysis of surfactant from amniotic fluid allows assessment of fetal lung maturity (FLM) in the human fetus and exogenous surfactant replacement therapy is part of the standard care in premature human infants. In contrast to human medicine, use and success of FLM testing or surfactant replacement therapy remain limited in veterinary medicine. Lung surfactant has been studied in large animal models of human disease. However, only a few reports exist on lung surfactant alterations in naturally occurring respiratory disease in large animals. This article gives a general review on the role of lung surfactant in respiratory disease followed by an overview of our current knowledge on surfactant in large animal veterinary medicine.
Collapse
Affiliation(s)
- U Christmann
- Department of Large Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Duck Pond Drive, Phase II, Blacksburg, VA 24061, USA.
| | | | | | | |
Collapse
|
36
|
Gerber F, Vandamme TF, Krafft MP. Impact of perfluorooctylethane on the formation of a semi-crystalline liquid-condensed phase in a phospholipid monolayer and of perfluorooctyl bromide on the adsorption of albumin on such a monolayer. CR CHIM 2009. [DOI: 10.1016/j.crci.2008.04.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
37
|
Pulmonary Surfactant: Biology and Therapy. THE RESPIRATORY TRACT IN PEDIATRIC CRITICAL ILLNESS AND INJURY 2009. [PMCID: PMC7124042 DOI: 10.1007/978-1-84800-925-7_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|
38
|
Ikegami M, Falcone A, Whitsett JA. STAT-3 regulates surfactant phospholipid homeostasis in normal lung and during endotoxin-mediated lung injury. J Appl Physiol (1985) 2008; 104:1753-60. [DOI: 10.1152/japplphysiol.00875.2007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Acute lung injury associated with surfactant deficiency remains a major cause of pulmonary morbidity and mortality. Since signal transducer and activator of transcription-3 (STAT-3) plays an important role in protecting respiratory epithelial cells during injury, we hypothesized that STAT-3 may regulate gene expression in type II cells that mediate surfactant phospholipid synthesis. Conditional deletion of Stat-3 in respiratory epithelial cells in the lung of transgenic mice ( Stat-3Δ/Δmice) decreased surfactant phospholipid synthesis and secretion. Deletion of Stat-3 was associated with decreased expression of Akt2, Srebf-1, and other genes expressed in type II cells that may influence surfactant phospholipid synthesis ( Glut-1, Slc34a2, Gpam, Acox2, and Cds2). Stat-3Δ/Δmice were more susceptible to intratracheal lipopolysaccharide (LPS). Saturated phosphatidylcholine and surfactant protein B levels were significantly decreased in bronchoalveolar lavage fluid from LPS-treated Stat-3Δ/Δmice. Alveolar capillary leak, proinflammatory cytokine expression, and perturbations of lung mechanics caused by LPS were exacerbated after deletion of STAT-3. STAT-3 plays a critical role in the regulation of surfactant lipid synthesis in the normal lung and during lung injury caused by LPS.
Collapse
|
39
|
Abstract
This article reviews exogenous surfactant therapy and its use in mitigating acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) in infants, children, and adults. Biophysical and animal research documenting surfactant dysfunction in ALI/ARDS is described, and the scientific rationale for treatment with exogenous surfactant is discussed. Major emphasis is placed on reviewing clinical studies of surfactant therapy in pediatric and adult patients who have ALI/ARDS. Particular advantages from surfactant therapy in direct pulmonary forms of these syndromes are described. Also discussed are additional factors affecting the efficacy of exogenous surfactants in ALI/ARDS.
Collapse
Affiliation(s)
- Douglas F Willson
- Pediatric ICU and Division of Pediatric Critical Care, University of Virginia Children's Medical Center, UVA Health Sciences System, Box 800386, Charlottesville, VA 22908-0386, USA.
| | | | | |
Collapse
|
40
|
Phenotypic heterogeneity in lung capillary and extra-alveolar endothelial cells. Increased extra-alveolar endothelial permeability is sufficient to decrease compliance. J Surg Res 2007; 143:70-7. [PMID: 17950075 DOI: 10.1016/j.jss.2007.03.047] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 02/20/2007] [Accepted: 03/05/2007] [Indexed: 12/21/2022]
Abstract
BACKGROUND In acute respiratory distress syndrome, pulmonary vascular permeability increases, causing intravascular fluid and protein to move into the lung's interstitium. The classic model describing the formation of pulmonary edema suggests that fluid crossing the capillary endothelium is drawn by negative interstitial pressure into the potential space surrounding extra-alveolar vessels and, as interstitial pressure builds, is forced into the alveolar air space. However, the validity of this model is challenged by animal models of acute lung injury in which extra-alveolar vessels are more permeable than capillaries under a variety of conditions. In the current study, we sought to determine whether extravascular fluid accumulation can be produced because of increased permeability of either the capillary or extra-alveolar endothelium, and whether different pathophysiology results from such site-specific increases in permeability. MATERIALS AND METHODS We perfused isolated lungs with either the plant alkaloid thapsigargin, which increases extra-alveolar endothelial permeability, or with 4alpha-phorbol 12, 13-didecanoate, which increases capillary endothelial permeability. RESULTS Both treatments produced equal increases in whole lung vascular permeability, but caused fluid accumulations in separate anatomical compartments. Light microscopy of isolated lungs showed that thapsigargin caused fluid cuffing of large vessels, while 4alpha-phorbol 12, 13-didecanoate caused alveolar flooding. Dynamic compliance was reduced in lungs with cuffing of large vessels, but not in lungs with alveolar flooding. CONCLUSIONS Phenotypic differences between vascular segments resulted in site-specific increases in permeability, which have different pathophysiological outcomes. Our findings suggest that insults leading to acute respiratory distress syndrome may increase permeability in extra-alveolar or capillary vascular segments, resulting in different pathophysiological sequela.
Collapse
|
41
|
Schmidt R, Markart P, Ruppert C, Wygrecka M, Kuchenbuch T, Walmrath D, Seeger W, Guenther A. Time-dependent changes in pulmonary surfactant function and composition in acute respiratory distress syndrome due to pneumonia or aspiration. Respir Res 2007; 8:55. [PMID: 17662121 PMCID: PMC1950506 DOI: 10.1186/1465-9921-8-55] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Accepted: 07/27/2007] [Indexed: 01/11/2023] Open
Abstract
Background Alterations to pulmonary surfactant composition have been encountered in the Acute Respiratory Distress Syndrome (ARDS). However, only few data are available regarding the time-course and duration of surfactant changes in ARDS patients, although this information may largely influence the optimum design of clinical trials addressing surfactant replacement therapy. We therefore examined the time-course of surfactant changes in 15 patients with direct ARDS (pneumonia, aspiration) over the first 8 days after onset of mechanical ventilation. Methods Three consecutive bronchoalveolar lavages (BAL) were performed shortly after intubation (T0), and four days (T1) and eight days (T2) after intubation. Fifteen healthy volunteers served as controls. Phospholipid-to-protein ratio in BAL fluids, phospholipid class profiles, phosphatidylcholine (PC) molecular species, surfactant proteins (SP)-A, -B, -C, -D, and relative content and surface tension properties of large surfactant aggregates (LA) were assessed. Results At T0, a severe and highly significant reduction in SP-A, SP-B and SP-C, the LA fraction, PC and phosphatidylglycerol (PG) percentages, and dipalmitoylation of PC (DPPC) was encountered. Surface activity of the LA fraction was greatly impaired. Over time, significant improvements were encountered especially in view of LA content, DPPC, PG and SP-A, but minimum surface tension of LA was not fully restored (15 mN/m at T2). A highly significant correlation was observed between PaO2/FiO2 and minimum surface tension (r = -0.83; p < 0.001), SP-C (r = 0.64; p < 0.001), and DPPC (r = 0.59; p = 0.003). Outcome analysis revealed that non-survivors had even more unfavourable surfactant properties as compared to survivors. Conclusion We concluded that a profound impairment of pulmonary surfactant composition and function occurs in the very early stage of the disease and only gradually resolves over time. These observations may explain why former surfactant replacement studies with a short treatment duration failed to improve outcome and may help to establish optimal composition and duration of surfactant administration in future surfactant replacement studies in acute lung injury.
Collapse
Affiliation(s)
- Reinhold Schmidt
- University of Giessen Lung Center (UGLC), Medical Clinic II, Giessen, Germany
| | - Philipp Markart
- University of Giessen Lung Center (UGLC), Medical Clinic II, Giessen, Germany
| | - Clemens Ruppert
- University of Giessen Lung Center (UGLC), Medical Clinic II, Giessen, Germany
| | - Malgorzata Wygrecka
- University of Giessen Lung Center (UGLC), Medical Clinic II, Giessen, Germany
| | - Tim Kuchenbuch
- University of Giessen Lung Center (UGLC), Medical Clinic II, Giessen, Germany
| | - Dieter Walmrath
- University of Giessen Lung Center (UGLC), Medical Clinic II, Giessen, Germany
| | - Werner Seeger
- University of Giessen Lung Center (UGLC), Medical Clinic II, Giessen, Germany
| | - Andreas Guenther
- University of Giessen Lung Center (UGLC), Medical Clinic II, Giessen, Germany
| |
Collapse
|
42
|
Biswas N, Waring AJ, Walther FJ, Dluhy RA. Structure and conformation of the disulfide bond in dimeric lung surfactant peptides SP-B1–25 and SP-B8–25. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1070-82. [PMID: 17349612 DOI: 10.1016/j.bbamem.2007.01.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2006] [Revised: 01/15/2007] [Accepted: 01/24/2007] [Indexed: 11/23/2022]
Abstract
Raman spectroscopy was used to determine the conformation of the disulfide linkage between cysteine residues in the homodimeric construct of the N-terminal alpha helical domain of surfactant protein B (dSP-B(1-25)). The conformation of the disulfide bond between cysteine residues in position 8 of the homodimer of dSP-B(1-25) was compared with that of a truncated homodimer (dSP-B(8-25)) of the peptide having a disulfide linkage at the same position in the alpha helix. Temperature-dependent Raman spectra of the S-S stretching region centered at approximately 500 cm(-1) indicated a stable, although highly strained disulfide conformation with a chi(CS-SC) dihedral angle of +/-10 degrees for the dSP-B(1-25) dimer. In contrast, the truncated dimer dSP-B(8-25) exhibited a series of disulfide conformations with the chi(CS-SC) dihedral angle taking on values of either +/-30 degrees or 85+/-20 degrees . For conformations with chi(CS-SC) close to the +/-90 degrees value, the Raman spectra of the 8-25 truncated dimers exhibited chi(SS-CC) dihedral angles of 90/180 degrees and 20-30 degrees . In the presence of a lipid mixture, both constructs showed a nu(S-S) band at approximately 488 cm(-1), corresponding to a chi(CS-SC) dihedral angle of +/-10 degrees . Polarized infrared spectroscopy was also used to determine the orientation of the helix and beta-sheet portion of both synthetic peptides. These calculations indicated that the helix was oriented primarily in the plane of the surface, at an angle of approximately 60-70 degrees to the surface normal, while the beta structure had approximately 40 degrees tilt. This orientation direction did not change in the presence of a lipid mixture or with temperature. These observations suggest that: (i) the conformational flexibility of the disulfide linkage is dependent on the amino acid residues that flank the cysteine disulfide bond, and (ii) in both constructs, the presence of a lipid matrix locks the disulfide bond into a preferred conformation.
Collapse
Affiliation(s)
- Nilanjana Biswas
- Department of Chemistry, University of Georgia, Athens, GA 30602-2556, USA
| | | | | | | |
Collapse
|
43
|
Gerber F, Krafft MP, Vandamme TF. The detrimental effect of serum albumin on the re-spreading of a dipalmitoyl phosphatidylcholine Langmuir monolayer is counteracted by a fluorocarbon gas. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:490-4. [PMID: 17097604 DOI: 10.1016/j.bbamem.2006.09.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Revised: 09/20/2006] [Accepted: 09/26/2006] [Indexed: 10/24/2022]
Abstract
We have recently reported that fluorocarbon gases exhibit an effective fluidizing effect on Langmuir monolayers of dipalmitoyl phosphatidylcholine (DPPC), preventing them from crystallizing up to surface pressures of approximately 40 mN m(-1), i.e. well above the DPPC's equilibrium surface pressure. We now report that gaseous perfluorooctyl bromide (gPFOB) promotes the re-spreading of DPPC Langmuir monolayers compressed on a bovine serum albumin (BSA)-containing sub-phase. The latter protein is known to maintain a concentration-dependent surface pressure that can exceed the re-spreading pressure of collapsed monolayers. This phenomenon was proposed to be responsible for lung surfactant inactivation. Compression/expansion isotherms and fluorescence microscopy experiments were carried out to assess the monolayers' physical state. We have found that, during expansion under gPFOB-containing air, the surface pressure of a DPPC monolayer on a BSA-containing sub-phase decreased to much lower values than when the DPPC monolayer was expanded in the presence of BSA under air ( approximately 0 mN m(-1) vs. approximately 7.5 mN m(-1) at 120 A(2), respectively). Moreover, fluorescence images showed that, during expansion, the BSA-coupled DPPC monolayers, in contact with gPFOB, remained in the liquid-expanded state for surface pressures lower than 10 mN m(-1), whereas they were in a liquid-condensed semi-crystalline state, even at large molecular areas (120 A(2)), when expanded under air. The re-incorporation of the PFOB molecules in the DPPC monolayer during expansion thus competes with the re-incorporation of BSA, thus preventing the latter from penetrating into the DPPC monolayer. We suggest that combinations of DPPC and a fluorocarbon gas may be useful in the treatment of lung conditions resulting from a deterioration of the native lung surfactant function due to plasma proteins, such as in the acute respiratory distress syndrome.
Collapse
Affiliation(s)
- Frédéric Gerber
- Institut Charles Sadron, UPR 22 CNRS, 6 rue Boussingault, 67083 Strasbourg Cedex, France; Laboratoire de Chimie Bioorganique, Faculté de Pharmacie, UMR 7514 CNRS, Université Louis Pasteur, 74 route du Rhin B.P.60024, 67401 Illkirch Cedex, France
| | | | | |
Collapse
|
44
|
Abstract
Regardless of the cause, a common pathophysiological feature of patients with acute respiratory distress syndrome is a dysfunction of the endogenous surfactant system. Although exogenous surfactant therapy has proven to be an effective treatment for neonatal respiratory distress syndrome, no similar current effective therapy exists for patients with acute respiratory distress syndrome. This is mainly due to the complexity of the lung injury that is involved with this disorder. Results from clinical trials, to date, have failed to show an improvement in patient survival after administration of exogenous surfactant; however, ongoing and future research efforts suggest that this therapy may eventually be feasible.
Collapse
Affiliation(s)
- Adam Maruscak
- St. Joseph's Health Centre, London, ON, N6A 4V2, Canada
| | | |
Collapse
|
45
|
Cepkova M, Matthay MA. Pharmacotherapy of acute lung injury and the acute respiratory distress syndrome. J Intensive Care Med 2006; 21:119-43. [PMID: 16672636 PMCID: PMC2765330 DOI: 10.1177/0885066606287045] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Acute lung injury and the acute respiratory distress syndrome are common syndromes with a high mortality rate that affect both medical and surgical patients. Better understanding of the pathophysiology of acute lung injury and the acute respiratory distress syndrome and advances in supportive care and mechanical ventilation have led to improved clinical outcomes since the syndrome was first described in 1967. Although several promising pharmacological therapies, including surfactant, nitric oxide, glucocorticoids and lysofylline, have been studied in patients with acute lung injury and the acute respiratory distress syndrome, none of these pharmacological treatments reduced mortality. This article provides an overview of pharmacological therapies of acute lung injury and the acute respiratory distress syndrome tested in clinical trials and current recommendations for their use as well as a discussion of potential future pharmacological therapies including beta(2)-adrenergic agonist therapy, keratinocyte growth factor, and activated protein C.
Collapse
Affiliation(s)
- Magda Cepkova
- Cardiovascular Research Institute, University of California San Francisco, CA 94143-0130, USA.
| | | |
Collapse
|
46
|
Akei H, Whitsett JA, Buroker M, Ninomiya T, Tatsumi H, Weaver TE, Ikegami M. Surface tension influences cell shape and phagocytosis in alveolar macrophages. Am J Physiol Lung Cell Mol Physiol 2006; 291:L572-9. [PMID: 16632521 DOI: 10.1152/ajplung.00060.2006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The effect of surface tension on alveolar macrophage shape and phagocytosis was assessed in vivo and in vitro. Surface tension was regulated in vivo by conditionally expressing surfactant protein (SP)-B in Sftpb-/- mice. Increased surface tension and respiratory distress were produced by depletion of SP-B and were readily reversed by repletion of SP-B in vivo. Electron microscopy was used to demonstrate that alveolar macrophages were usually located beneath the surfactant film on the alveolar surfaces. Reduction of SP-B increased surface tension and resulted in flattening of alveolar macrophages on epithelial surfaces in vivo. Phagocytosis of intratracheally injected fluorescent microbeads by alveolar macrophages was decreased during SP-B deficiency and was restored by repletion of SP-B in vivo. Incubation of MH-S cells, a mouse macrophage cell line, with inactive surfactant caused cell flattening and decreased phagocytosis in vitro, findings that were reversed by the addition of sheep surfactant or phospholipid containing SP-B. SP-B controls surface tension by forming a surfactant phospholipid film that regulates shape and nonspecific phagocytic activity of alveolar macrophages on the alveolar surface.
Collapse
Affiliation(s)
- Hiroko Akei
- Cincinnati Children's Hospital, Division of Pulmonary Biology, University of Cincinnati, OH 45229-3039, USA
| | | | | | | | | | | | | |
Collapse
|
47
|
Dluhy R, Shanmukh S, Morita SI. The application of two-dimensional correlation spectroscopy to surface and interfacial analysis. SURF INTERFACE ANAL 2006. [DOI: 10.1002/sia.2358] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
48
|
Strohmaier W, Trupka A, Pfeiler C, Thurnher M, Khakpour Z, Gippner-Steppert C, Jochum M, Redl H. Bilateral lavage with diluted surfactant improves lung function after unilateral lung contusion in pigs*. Crit Care Med 2005; 33:2286-93. [PMID: 16215383 DOI: 10.1097/01.ccm.0000182819.11807.16] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE This study evaluates the effects of bronchoalveolar lavage with diluted surfactant on unilateral lung contusion-induced lung dysfunction. DESIGN Randomized prospective animal study. SETTING An animal laboratory. SUBJECTS Twenty adult pigs, weighing 25-35 kg. INTERVENTIONS Animals were randomly assigned to controls and surfactant treatment. Bilateral lavage with surfactant treatment began 30 mins after unilateral lung contusion. Then 25 mg/kg of body weight diluted Curosurf (5 mg/mL) was applied in a volume of 5 mL/kg of body weight. Observation time was 8 hrs postinjury. MEASUREMENTS AND MAIN RESULTS The Pao2/Fio2 ratio fell from 500 to 250 and then recovered gradually in controls and surfactant-treated pigs. After another 4 hrs, the Pao2/Fio2 ratio deteriorated again in controls, but not in surfactant-treated animals. Total compliance fell by 50% after injury but was completely restored by surfactant treatment. Lung contusion increased the median number of neutrophils in bronchoalveolar lavage fluid from 2% to 30% of total cells and peaked >60% at 480 mins in the contused lungs of control pigs. Surfactant-treated pigs had 40% neutrophils at 480 mins without reaching significant difference to controls. The leukocyte neutral proteinase inhibitor increased to 500 ng/mL at 30 mins postinjury in the contused lungs and increased to 2000 ng/mL after surfactant treatment. CONCLUSIONS Bilateral bronchoalveolar lavage with diluted surfactant can effectively improve lung function after experimental unilateral lung contusion in pigs.
Collapse
Affiliation(s)
- Wolfgang Strohmaier
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Donaueschingenstrasse13, 1200 Vienna, Austria
| | | | | | | | | | | | | | | |
Collapse
|
49
|
Thomas NJ, Hollenbeak CS, Lucking SE, Willson DF. Cost-effectiveness of exogenous surfactant therapy in pediatric patients with acute hypoxemic respiratory failure. Pediatr Crit Care Med 2005; 6:160-5. [PMID: 15730602 DOI: 10.1097/01.pcc.0000154965.08432.16] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To determine whether the use of exogenous surfactant (Infasurf) in pediatric acute hypoxemic respiratory failure is cost-effective. DESIGN Deterministic cost-effectiveness analysis based on a Markov model. The model was calibrated using outcomes and resource utilization observed in a multiple-centered, prospective, randomized, controlled unblinded trial of Infasurf in pediatric acute hypoxemic respiratory failure. Costs were short-run direct costs estimated from the perspective of the hospital as provider. Primary outcomes were expected costs, expected survival rates, and incremental cost per life saved. SETTING Patients in the trial were treated in one of eight pediatric intensive care units of tertiary medical centers. PATIENTS Forty-two children with acute hypoxemic respiratory failure who were randomized to receive either standard therapy or exogenous surfactant in addition to standard therapy. MEASUREMENTS AND MAIN RESULTS Our baseline analysis suggests that for a 10-kg child, the Infasurf strategy is both less costly (62,922 US dollars vs. 74,006 US dollars) and more effective (survival: 90.3% vs. 85.1%) and therefore dominates standard treatment. Cost savings were realized in the model because patients in the surfactant group were more likely to leave the pediatric intensive care unit sooner. The Infasurf strategy continues to dominate for children up to 60 kg. At 70 kg, the cost to save an additional life using the Infasurf strategy is 79,805 US dollars, which is still cost-effective if the provider is willing to make this tradeoff. CONCLUSIONS For the majority of pediatric patients with acute hypoxemic respiratory failure, exogenous surfactant is cost-effective. If the use of this medication becomes standard care, a greater variety of packaging sizes could lead to decreased acquisition costs and increase the number of patients for whom this treatment is cost-effective.
Collapse
Affiliation(s)
- Neal J Thomas
- Department of Pediatrics, Division of Pediatric Critical Care Medicine, Penn State Children's Hospital, Hershey, PA 17033, USA.
| | | | | | | |
Collapse
|
50
|
Yapicioğlu H, Yildizdaş D, Bayram I, Sertdemir Y, Yilmaz HL. The use of surfactant in children with acute respiratory distress syndrome: efficacy in terms of oxygenation, ventilation and mortality. Pulm Pharmacol Ther 2004; 16:327-33. [PMID: 14580923 DOI: 10.1016/s1094-5539(03)00088-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE The aim of this prospectively designed study was to investigate the efficacy of surfactant (S) for acute respiratory distress syndrome (ARDS) in children. MATERIALS AND METHODS Children with ARDS were included in this study. Surfactant (Survanta, Abbott, USA) was given intratracheally at a dose of 150 mg/kg every 12 h for a total of two doses. During the study period none of the patients received permissive hypercapnia, high frequency ventilation, nitric oxide or ECMO. Peak inspiratory pressure (PIP), positive end expiratory pressure (PEEP), ventilation rate, mean airway pressure, tidal volume (TV), Murray index, PaO2/FiO2, ventilation index (VI), oxygen index (OI) and arterial oxygen tension difference (A-aDO2) were measured before and 48 h after surfactant treatment. Duration of mechanical ventilation therapy, duration in paediatric intensive care unit (PICU) and mortality rate were recorded. RESULTS Among the 36 children who met the inclusion criteria, 12 were treated with surfactant. The mean age was 72.5+/-56.2 months; 47% of children were male. Infants were ventilated by pressure-controlled ventilators whereas for older children volume-controlled ventilators were used. Sepsis (42%) was the main predisposing factor followed by pneumonia (25%) and malignancy (17%). The baseline characteristics including age, predisposing factors, gender, PIP, PEEP, A-aDO2, PaO2/FiO2, OI, TV, VI and Murray index were similar in the surfactant and non-surfactant (NS) group (p>0.05). There were significant improvements in PIP, PEEP, A-aDO2, PaO2/FiO2, OI, TV, VI and Murray index in the surfactant group after surfactant treatment compared with NS group (p<0.05). Duration of PICU stay and ventilator treatment was longer in NS group (14+/-3.7, 1.8+/-3.2 days vs. 9.2+/-3.1, 8.6+/-1.9 days), (p<0.05). Mortality rate was 42% in surfactant compared with 63% in the NS group, (p>0.05). Children in the surfactant group lived significantly longer (p<0.05). CONCLUSIONS Modified natural surfactant is an effective treatment option in children with ARDS for improving gas exchange, decreasing the use of ventilatory support and increasing survival time.
Collapse
Affiliation(s)
- Hacer Yapicioğlu
- Department of Paediatrics, Division of Neonatology, Faculty of Medicine, Cukurova University, 01330 Adana, Turkey.
| | | | | | | | | |
Collapse
|