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Report of the ISHLT Working Group on primary lung graft dysfunction Part IV: Prevention and treatment: A 2016 Consensus Group statement of the International Society for Heart and Lung Transplantation. J Heart Lung Transplant 2017; 36:1121-1136. [DOI: 10.1016/j.healun.2017.07.013] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Accepted: 07/16/2017] [Indexed: 12/14/2022] Open
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Ochs M, Knudsen L, Hegermann J, Wrede C, Grothausmann R, Mühlfeld C. Using electron microscopes to look into the lung. Histochem Cell Biol 2016; 146:695-707. [PMID: 27688057 DOI: 10.1007/s00418-016-1502-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2016] [Indexed: 02/06/2023]
Abstract
In the nineteenth century, there was a dispute about the existence of a lung alveolar epithelium which remained unsolved until the invention of electron microscopy (EM) and its application to the lung. From the early 1960s, Ewald Weibel became the master of lung EM. He showed that the alveolar epithelium is covered with a lining layer containing surfactant. Weibel also explained the phenomenon of "non-nucleated plates" observed already in 1881 by Albert Kölliker. Weibel's most significant contribution was to the development of stereological methods. Therefore, quantitative characterization of lung structure revealing structure-function relationships became possible. Today, the spectrum of EM methods to study the fine structure of the lung has been extended significantly. Cryo-preparation techniques are available which are necessary for immunogold labeling of molecules. Energy-filtering techniques can be used for the detection of elements. There have also been major improvements in stereology, thus providing a very versatile toolbox for quantitative lung phenotype analyses. A new dimension was added by 3D EM techniques. Depending on the desired sample size and resolution, the spectrum ranges from array tomography via serial block face scanning EM and focused ion beam scanning EM to electron tomography. These 3D datasets provide new insights into lung ultrastructure. Biomedical EM is an ever-developing field. Its high resolution remains unparalleled. Moreover, EM has the unique advantage of providing an "open view" into cells and tissues within their full architectural context. Therefore, EM will remain an indispensable tool for a better understanding of the lung's functional design.
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Affiliation(s)
- Matthias Ochs
- Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. .,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany. .,REBIRTH Cluster of Excellence, Hannover, Germany.
| | - Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany.,REBIRTH Cluster of Excellence, Hannover, Germany
| | - Jan Hegermann
- Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,REBIRTH Cluster of Excellence, Hannover, Germany
| | - Christoph Wrede
- Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,REBIRTH Cluster of Excellence, Hannover, Germany
| | - Roman Grothausmann
- Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,REBIRTH Cluster of Excellence, Hannover, Germany
| | - Christian Mühlfeld
- Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany.,REBIRTH Cluster of Excellence, Hannover, Germany
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Schmiedl A, Grützner D, Hoffmann T, von Hörsten S, Stephan M. DPP4 inhibitors increase differentially the expression of surfactant proteins in Fischer 344 rats. Acta Physiol (Oxf) 2014; 212:248-61. [PMID: 25069535 DOI: 10.1111/apha.12350] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 04/17/2014] [Accepted: 07/19/2014] [Indexed: 01/21/2023]
Abstract
AIM Intact surface active agent (surfactant) composed of surfactant-associated proteins (SPs) and lipids is necessary for respiration and prevents alveoli from collapsing. CD26, a transmembrane glycoprotein exerting dipeptidyl peptidase activity (DPP4), highly expressed in lung parenchyma, is involved in inflammatory processes. A pharmacological inhibition of DPP4 influenced not only the inflammation but also elevated the SPs. Thus, DPP4 inhibitors may be a novel drug for treatment of diseases with surfactant deficiency. Therefore, we tested firstly the hypothesis that DPP4 inhibitors increase the expression of SPs in healthy rats. METHODS SP mRNA and protein expression were determined different times after nebulization of aerosolized DPP4 inhibitors [L-isoleucine-thiazolidide (L-Ile-Thia), L-valine-pyrrolidide (L-Val-Pyrr)], budesonide, saline or stereoisomers. RESULTS Compared with negative controls (1) L-Ile-Thia as well as budesonide led to a significant higher and L-Val-Pyrr had the tendency to a significant higher expression of SP-A mRNA 6 h after nebulization, (2) the expression of SP-D mRNA increased significantly 6 h after nebulization with L-Ile-Thia and 3 and 6 h after nebulization with Val-pyrr, (3) SP-B mRNA levels showed significantly higher values 3 and 6 h after nebulization with L-Val-Pyrr, (4) protein levels of SP-A, SP-B and SP-C were elevated significantly 6 h after nebulization with L-Val-Pyrr as well as with budesonide, and (5) phospholipids were also increased in response to DPP4 inhibition; the minimal surface tension was comparable. CONCLUSION DPP4 inhibition influence differently the expression of surfactant proteins in healthy rats and may be suitable to elevate surfactant synthesis in different diseases accompanied with surfactant deficiencies.
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Affiliation(s)
- A. Schmiedl
- Institute of Functional and Applied Anatomy; Hannover Medical School; Hannover Germany
| | - D. Grützner
- Institute of Functional and Applied Anatomy; Hannover Medical School; Hannover Germany
| | | | - S. von Hörsten
- Department for Experimental Therapy; Franz-Penzoldt-Center; Friedrich-Alexander-University Erlangen-Nürnberg; Erlangen Germany
| | - M. Stephan
- Clinic for Psychosomatics and Psychotherapy; Hannover Medical School; Hannover Germany
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Wittwer T, Rahmanian P, Choi YH, Zeriouh M, Karavidic S, Neef K, Christmann A, Piatkowski T, Schnapper A, Ochs M, Mühlfeld C, Wahlers T. Mesenchymal stem cell pretreatment of non-heart-beating-donors in experimental lung transplantation. J Cardiothorac Surg 2014; 9:151. [PMID: 25179441 PMCID: PMC4169637 DOI: 10.1186/s13019-014-0151-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 08/18/2014] [Indexed: 12/30/2022] Open
Abstract
Background Lung transplantation (LTx) is still limited by organ shortage. To expand the donor pool, lung retrieval from non-heart-beating donors (NHBD) was introduced into clinical practice recently. However, primary graft dysfunction with inactivation of endogenous surfactant due to ischemia/reperfusion-injury is a major cause of early mortality. Furthermore, donor-derived human mesenchymal stem cell (hMSC) expansion and fibrotic differentiation in the allograft results in bronchiolitis obliterans syndrome (BOS), a leading cause of post-LTx long-term mortality. Therefore, pretreatment of NHBD with recipient-specific bone-marrow-(BM)-derived hMSC might have the potential to both improve the postischemic allograft function and influence the long-term development of BOS by the numerous paracrine, immunomodulating and tissue-remodeling properties especially on type-II-pneumocytes of hMSC. Methods Asystolic pigs (n = 5/group) were ventilated for 3 h of warm ischemia (groups 2–4). 50x106 mesenchymal-stem-cells (MSC) were administered in the pulmonary artery (group 3) or nebulized endobronchially (group 4) before lung preservation. Following left-lung-transplantation, grafts were reperfused, pulmonary-vascular-resistance (PVR), oxygenation and dynamic-lung-compliance (DLC) were monitored and compared to control-lungs (group 2) and sham-controls (group 1). To prove and localize hMSC in the lung, cryosections were counter-stained. Intra-alveolar edema was determined stereologically. Statistics comprised ANOVA with repeated measurements. Results Oxygenation (p = 0.001) and PVR (p = 0.009) following endovascular application of hMSC were significantly inferior compared to Sham controls, whereas DLC was significantly higher in endobronchially pretreated lungs (p = 0.045) with overall sham-comparable outcome regarding oxygenation and PVR. Stereology revealed low intrapulmonary edema in all groups (p > 0.05). In cryosections of both unreperfused and reperfused grafts, hMSC were localized in vessels of alveolar septa (endovascular application) and alveolar lumen (endobronchial application), respectively. Conclusions Preischemic deposition of hMSC in donor lungs is feasible and effective, and endobronchial application is associated with significantly better DLC as compared to sham controls. In contrast, transvascular hMSC delivery results in inferior oxygenation and PVR. In the long term perspective, due to immunomodulatory, paracrine and tissue-remodeling effects on epithelial and endothelial restitution, an endobronchial NHBD allograft-pretreatment with autologous mesenchymal-stem-cells to attenuate limiting bronchiolitis-obliterans-syndrome in the long-term perspective might be promising in clinical lung transplantation. Subsequent work with chronic experiments is initiated to further elucidate this important field. Electronic supplementary material The online version of this article (doi:10.1186/s13019-014-0151-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Thorsten Wittwer
- Department of Cardiothoracic Surgery, Heart Center, University of Cologne, Kerpener Strasse 61, Cologne, 50924, Germany.
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Herrmann G, Knudsen L, Madershahian N, Mühlfeld C, Frank K, Rahmanian P, Wahlers T, Wittwer T, Ochs M. Effects of exogenous surfactant on the non-heart-beating donor lung graft in experimental lung transplantation - a stereological study. J Anat 2014; 224:594-602. [PMID: 24527871 DOI: 10.1111/joa.12167] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2014] [Indexed: 11/29/2022] Open
Abstract
The use of non-heart-beating donor (NHBD) lungs may help to overcome the shortage of lung grafts in clinical lung transplantation, but warm ischaemia and ischaemia/reperfusion injury (I/R injury) resulting in primary graft dysfunction represent a considerable threat. Thus, better strategies for optimized preservation of lung grafts are urgently needed. Surfactant dysfunction has been shown to contribute to I/R injury, and surfactant replacement therapy is effective in enhancing lung function and structural integrity in related rat models. In the present study we hypothesize that surfactant replacement therapy reduces oedema formation in a pig model of NHBD lung transplantation. Oedema formation was quantified with (SF) and without (non-SF) surfactant replacement therapy in interstitial and alveolar compartments by means of design-based stereology in NHBD lungs 7 h after cardiac arrest, reperfusion and transplantation. A sham-operated group served as control. In both NHBD groups, nearly all animals died within the first hours after transplantation due to right heart failure. Both SF and non-SF developed an interstitial oedema of similar degree, as shown by an increase in septal wall volume and arithmetic mean thickness as well as an increase in the volume of peribron-chovascular connective tissue. Regarding intra-alveolar oedema, no statistically significant difference could be found between SF and non-SF. In conclusion, surfactant replacement therapy cannot prevent poor outcome after prolonged warm ischaemia of 7 h in this model. While the beneficial effects of surfactant replacement therapy have been observed in several experimental and clinical studies related to heart-beating donor lungs and cold ischaemia, it is unlikely that surfactant replacement therapy will overcome the shortage of organs in the context of prolonged warm ischaemia, for example, 7 h. Moreover, our data demonstrate that right heart function and dysfunctions of the pulmonary vascular bed are limiting factors that need to be addressed in NHBD.
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Mühlfeld C, Ochs M. Quantitative microscopy of the lung: a problem-based approach. Part 2: stereological parameters and study designs in various diseases of the respiratory tract. Am J Physiol Lung Cell Mol Physiol 2013; 305:L205-21. [PMID: 23709622 DOI: 10.1152/ajplung.00427.2012] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Design-based stereology provides efficient methods to obtain valuable quantitative information of the respiratory tract in various diseases. However, the choice of the most relevant parameters in a specific disease setting has to be deduced from the present pathobiological knowledge. Often it is difficult to express the pathological alterations by interpretable parameters in terms of volume, surface area, length, or number. In the second part of this companion review article, we analyze the present pathophysiological knowledge about acute lung injury, diffuse parenchymal lung diseases, emphysema, pulmonary hypertension, and asthma to come up with recommendations for the disease-specific application of stereological principles for obtaining relevant parameters. Worked examples with illustrative images are used to demonstrate the work flow, estimation procedure, and calculation and to facilitate the practical performance of equivalent analyses.
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Affiliation(s)
- Christian Mühlfeld
- Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
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Wittwer T, Madershahian N, Rahmanian P, Choi YH, Neef K, Frank K, Müller-Ehmsen J, Ochs M, Mühlfeld C, Wahlers T. Surfactant application in experimental lung transplantation. J Heart Lung Transplant 2013; 32:355-9. [DOI: 10.1016/j.healun.2012.11.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 11/19/2012] [Accepted: 11/29/2012] [Indexed: 12/17/2022] Open
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Knudsen L, Ochs M. Microscopy-based quantitative analysis of lung structure: application in diagnosis. ACTA ACUST UNITED AC 2011; 5:319-31. [PMID: 23484552 DOI: 10.1517/17530059.2011.577414] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Stereology provides a set of methods that are appropriate for a microscopy-based quantitative assessment of lung structure. In general, the aim of stereology is to obtain information on three-dimensional structures from two-dimensional sections of these structures. The inherent impartiality of stereological principles is critical in order to meet the requirements of 'good laboratory practice'. AREAS COVERED This article is a systematic review of the applications of stereology to characterize pathological alterations of emphysema, fibrosis, acute lung injury and tumor grading. The reader is provided with a general overview of unbiased or design-based stereology and is provided with some examples of how these methods could be integrated into a diagnostic work-up of lung diseases in humans and animal models. The article also reviews the implications of a published statement, which defines standards for quantitative assessment of lung structure based on stereology, by the American Thoracic Society and the European Respiratory Society. EXPERT OPINION In view of the recently published standards for quantitative assessment of lung structure, unbiased stereological methods are strongly recommended, particularly as they provide valuable information in diagnosing lung diseases and allow a statistically valid quantitative comparison between different groups. Future developments will make the application of stereology in lung biology and pathology even more efficient. Moreover, there is also the potential for combing the principles of stereology with other imaging modalities (e.g., radiological), which will allow for non-invasive lung stereology.
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Affiliation(s)
- Lars Knudsen
- Institute of Functional and Applied Anatomy , Hannover Medical School, Carl-Neuberg Str. 1, 30625 Hannover , Germany
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Feng D, Zhang S, Hu Z, Fan F, Jiang F, Yin R, Xu L. Dynamic investigation of alveolar type II cell function in a long-term survival model of rat lung ischemia-reperfusion injury. Scandinavian Journal of Clinical and Laboratory Investigation 2010; 70:364-73. [PMID: 20560845 DOI: 10.3109/00365513.2010.495415] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Alveolar type II (ATII) cells are capable of repairing the alveolar epithelium injury induced by lung ischemia-reperfusion injury (LIRI). In the present study, we aim to dynamically investigate the morphological and functional alternations of ATII cells using a long-term survival model of rat LIRI. MATERIALS AND METHODS Male Sprague-Dawley rats were randomized into sham and ischemia-reperfusion (IR) groups. Animals of IR group underwent warm ischemia for 60 minutes by left pulmonary hilum occlusion. Injury was assessed by histological examination and myeloperoxidase activity assay. The proliferation profile of ATII cells was evaluated by immunofluorescence double staining. Surfactant protein-C (SP-C) and caspase-3 expression were determined by reverse transcription polymerase chain reaction. Ultrastructure and stereological analysis were used to quantify the alterations of nuclei and lamellar bodies (LBs) of ATII cells. RESULTS As compared with the sham group, SP-C expression in the IR group significantly decreased at the early phase of LIRI and returned to normal in 7 days after reperfusion. SP-C/PCNA double positive cell number significantly increased at 1d, peaked at 3d and decreased to normal until 7 days after reperfusion. Ultrastructure and stereological analysis of ATII cells also showed that LBs were remarkably impaired at the early phase of LIRI and recovered up to 7 days after reperfusion. CONCLUSIONS This model is simple, stable and reproducible. ATII cells demonstrated a self-repair capacity in a slow manner following the early phase of LIRI. Enhancing self-repair capacity of ATII cells may be a potential way of alleviating or curing LIRI.
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Affiliation(s)
- Dongjie Feng
- Department of Thoracic Surgery, Nanjing Medical University Affiliated Cancer Hospital of Jiangsu Province, Cancer Institution of Jiangsu Province, Nanjing, P. R. China
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Mühlfeld C, Becker L, Bussinger C, Vollroth M, Nagib R, Schaefer IM, Knudsen L, Richter J, Madershahian N, Wahlers T, Wittwer T, Ochs M. Exogenous surfactant in ischemia/reperfusion: Effects on endogenous surfactant pools. J Heart Lung Transplant 2010; 29:327-34. [DOI: 10.1016/j.healun.2009.07.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Revised: 07/28/2009] [Accepted: 07/29/2009] [Indexed: 11/26/2022] Open
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Protective mechanism of ultrafiltration against cardiopulmonary bypass-induced lung injury. Transplant Proc 2010; 41:3845-8. [PMID: 19917399 DOI: 10.1016/j.transproceed.2009.04.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Accepted: 04/13/2009] [Indexed: 11/20/2022]
Abstract
BACKGROUND We previously demonstrated a negative effect of cardiopulmonary bypass (CPB) in a canine model of single-lung graft function and an improved effect with ultrafiltration during CPB. OBJECTIVE To investigate the mechanism of these effects, focusing on cytokines and pulmonary surfactants using real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). MATERIALS AND METHODS Fifteen left-sided single-lung transplant procedures were performed in pairs of dogs. The animals were divided into 3 groups. In one group, transplantation was performed without CPB (non-CPB group); in a second group, transplantation was performed with CPB and CPB flow was decreased slowly and pulmonary artery pressure was controlled (CPB group; and in the third group, transplantation was performed with CPB and ultrafiltration (CPB+UF group). Grafted lung specimens were harvested for RT-PCR of cytokines (IL-6, IL-8, and IL-10) and surfactant proteins (SP-A, SP-B, and SP-C). RESULTS Real-time quantitative RT-PCR demonstrated increased IL-6 expression in the CPB group compared with the non-CPB group. IL-6 gene expression was suppressed and pulmonary surfactant restored using ultrafiltration. Gene expression of surfactant protein (SP)-A, SP-B, and SP-C was decreased in the CPB group compared with normal lung and ultrafiltration groups, which demonstrated sustained gene expression of SP-A and SP-B. CONCLUSION Cardiopulmonary bypass has negative effects on grafts; however, ultrafiltration attenuates acute lung dysfunction by decreasing the inflammatory response and increasing pulmonary surfactant.
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Dreyer N, Mühlfeld C, Fehrenbach A, Pech T, von Berg S, Nagib R, Richter J, Wittwer T, Wahlers T, Ochs M. Exogenous surfactant application in a rat lung ischemia reperfusion injury model: effects on edema formation and alveolar type II cells. Respir Res 2008; 9:5. [PMID: 18205928 PMCID: PMC2265285 DOI: 10.1186/1465-9921-9-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Accepted: 01/18/2008] [Indexed: 11/23/2022] Open
Abstract
Background Prophylactic exogenous surfactant therapy is a promising way to attenuate the ischemia and reperfusion (I/R) injury associated with lung transplantation and thereby to decrease the clinical occurrence of acute lung injury and acute respiratory distress syndrome. However, there is little information on the mode by which exogenous surfactant attenuates I/R injury of the lung. We hypothesized that exogenous surfactant may act by limiting pulmonary edema formation and by enhancing alveolar type II cell and lamellar body preservation. Therefore, we investigated the effect of exogenous surfactant therapy on the formation of pulmonary edema in different lung compartments and on the ultrastructure of the surfactant producing alveolar epithelial type II cells. Methods Rats were randomly assigned to a control, Celsior (CE) or Celsior + surfactant (CE+S) group (n = 5 each). In both Celsior groups, the lungs were flush-perfused with Celsior and subsequently exposed to 4 h of extracorporeal ischemia at 4°C and 50 min of reperfusion at 37°C. The CE+S group received an intratracheal bolus of a modified natural bovine surfactant at a dosage of 50 mg/kg body weight before flush perfusion. After reperfusion (Celsior groups) or immediately after sacrifice (Control), the lungs were fixed by vascular perfusion and processed for light and electron microscopy. Stereology was used to quantify edematous changes as well as alterations of the alveolar epithelial type II cells. Results Surfactant treatment decreased the intraalveolar edema formation (mean (coefficient of variation): CE: 160 mm3 (0.61) vs. CE+S: 4 mm3 (0.75); p < 0.05) and the development of atelectases (CE: 342 mm3 (0.90) vs. CE+S: 0 mm3; p < 0.05) but led to a higher degree of peribronchovascular edema (CE: 89 mm3 (0.39) vs. CE+S: 268 mm3 (0.43); p < 0.05). Alveolar type II cells were similarly swollen in CE (423 μm3(0.10)) and CE+S (481 μm3(0.10)) compared with controls (323 μm3(0.07); p < 0.05 vs. CE and CE+S). The number of lamellar bodies was increased and the mean lamellar body volume was decreased in both CE groups compared with the control group (p < 0.05). Conclusion Intratracheal surfactant application before I/R significantly reduces the intraalveolar edema formation and development of atelectases but leads to an increased development of peribronchovascular edema. Morphological changes of alveolar type II cells due to I/R are not affected by surfactant treatment. The beneficial effects of exogenous surfactant therapy are related to the intraalveolar activity of the exogenous surfactant.
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Affiliation(s)
- Niels Dreyer
- Department of Anatomy, Division of Electron Microscopy, University of Göttingen, Kreuzbergring 36, D-37075 Göttingen, Germany.
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Mühlfeld C, Rothen-Rutishauser B, Vanhecke D, Blank F, Gehr P, Ochs M. Visualization and quantitative analysis of nanoparticles in the respiratory tract by transmission electron microscopy. Part Fibre Toxicol 2007; 4:11. [PMID: 17996124 PMCID: PMC2211502 DOI: 10.1186/1743-8977-4-11] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Accepted: 11/12/2007] [Indexed: 11/11/2022] Open
Abstract
Nanotechnology in its widest sense seeks to exploit the special biophysical and chemical properties of materials at the nanoscale. While the potential technological, diagnostic or therapeutic applications are promising there is a growing body of evidence that the special technological features of nanoparticulate material are associated with biological effects formerly not attributed to the same materials at a larger particle scale. Therefore, studies that address the potential hazards of nanoparticles on biological systems including human health are required. Due to its large surface area the lung is one of the major sites of interaction with inhaled nanoparticles. One of the great challenges of studying particle-lung interactions is the microscopic visualization of nanoparticles within tissues or single cells both in vivo and in vitro. Once a certain type of nanoparticle can be identified unambiguously using microscopic methods it is desirable to quantify the particle distribution within a cell, an organ or the whole organism. Transmission electron microscopy provides an ideal tool to perform qualitative and quantitative analyses of particle-related structural changes of the respiratory tract, to reveal the localization of nanoparticles within tissues and cells and to investigate the 3D nature of nanoparticle-lung interactions.This article provides information on the applicability, advantages and disadvantages of electron microscopic preparation techniques and several advanced transmission electron microscopic methods including conventional, immuno and energy-filtered electron microscopy as well as electron tomography for the visualization of both model nanoparticles (e.g. polystyrene) and technologically relevant nanoparticles (e.g. titanium dioxide). Furthermore, we highlight possibilities to combine light and electron microscopic techniques in a correlative approach. Finally, we demonstrate a formal quantitative, i.e. stereological approach to analyze the distributions of nanoparticles in tissues and cells.This comprehensive article aims to provide a basis for scientists in nanoparticle research to integrate electron microscopic analyses into their study design and to select the appropriate microscopic strategy.
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Affiliation(s)
- Christian Mühlfeld
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3000 Bern 9, Switzerland
| | | | - Dimitri Vanhecke
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3000 Bern 9, Switzerland
| | - Fabian Blank
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3000 Bern 9, Switzerland
| | - Peter Gehr
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3000 Bern 9, Switzerland
| | - Matthias Ochs
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3000 Bern 9, Switzerland
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Mühlfeld C, Müller K, Pallesen LP, Sandhaus T, Madershahian N, Richter J, Wahlers T, Wittwer T, Ochs M. Impact of preservation solution on the extent of blood-air barrier damage and edema formation in experimental lung transplantation. Anat Rec (Hoboken) 2007; 290:491-500. [PMID: 17377949 DOI: 10.1002/ar.20518] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A major aim in lung transplantation is to prevent the loss of structural integrity due to ischemia and reperfusion (I/R) injury. Preservation solutions protect the lung against I/R injury to a variable extent. We compared the influence of two extracellular-type preservation solutions (Perfadex, or PX, and Celsior, or CE) on the morphological alterations induced by I/R. Pigs were randomly assigned to sham (n = 4), PX (n = 5), or CE (n = 2) group. After flush perfusion with PX or CE, donor lungs were excised and stored for 27 hr at 4 degrees C. The left donor lung was implanted into the recipient, reperfused for 6 hr, and, afterward, prepared for light and electron microscopy. Intra-alveolar, septal, and peribronchovascular edema as well as the integrity of the blood-air barrier were determined stereologically. Intra-alveolar edema was more pronounced in CE (219.80 +/- 207.55 ml) than in PX (31.46 +/- 15.75 ml). Peribronchovascular (sham: 13.20 +/- 4.99 ml; PX: 15.57 +/- 5.53 ml; CE: 31.56 +/- 5.78 ml) and septal edema (thickness of alveolar septal interstitium, sham: 98 +/- 33 nm; PX: 84 +/- 8 nm; CE: 249 +/- 85 nm) were only found in CE. The blood-air barrier was similarly well preserved in sham and PX but showed larger areas of swollen and fragmented epithelium or endothelium in CE. The present study shows that Perfadex effectively prevents intra-alveolar, septal, and peribronchovascular edema formation as well as injury of the blood-air barrier during I/R. Celsior was not effective in preserving the lung from morphological I/R injury.
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Weibel ER, Hsia CCW, Ochs M. How much is there really? Why stereology is essential in lung morphometry. J Appl Physiol (1985) 2006; 102:459-67. [PMID: 16973815 DOI: 10.1152/japplphysiol.00808.2006] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Quantitative data on lung structure are essential to set up structure-function models for assessing the functional performance of the lung or to make statistically valid comparisons in experimental morphology, physiology, or pathology. The methods of choice for microscopy-based lung morphometry are those of stereology, the science of quantitative characterization of irregular three-dimensional objects on the basis of measurements made on two-dimensional sections. From a practical perspective, stereology is an assumption-free set of methods of unbiased sampling with geometric probes, based on a solid mathematical foundation. Here, we discuss the pitfalls of lung morphometry and present solutions, from specimen preparation to the sampling scheme in multiple stages, for obtaining unbiased estimates of morphometric parameters such as volumes, surfaces, lengths, and numbers. This is demonstrated on various examples. Stereological methods are accurate, efficient, simple, and transparent; the precision of the estimates depends on the size and distribution of the sample. For obtaining quantitative data on lung structure at all microscopic levels, state-of-the-art stereology is the gold standard.
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Affiliation(s)
- Ewald R Weibel
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3000 Bern 9, Switzerland
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Abstract
Lung stereology has a long and successful tradition. From mice to men, the application of new stereological methods at several levels (alveoli, parenchymal cells, organelles, proteins) has led to new insights into normal lung architecture, parenchymal remodelling in emphysema-like pathology, alveolar type II cell hyperplasia and hypertrophy and intracellular surfactant alterations as well as distribution of surfactant proteins. The Euler number of the network of alveolar openings, estimated using physical disectors at the light microscopic level, is an unbiased and direct estimate of alveolar number. Surfactant-producing alveolar type II cells can be counted and sampled for local size estimation with physical disectors at a high magnification light microscopic level. The number of their surfactant storage organelles, lamellar bodies, can be estimated using physical disectors at the EM level. By immunoelectron microscopy, surfactant protein distribution can be analysed with the relative labelling index. Together with the well-established classical stereological methods, these design-based methods now allow for a complete quantitative phenotype analysis in lung development and disease, including the structural characterization of gene-manipulated mice, at the light and electron microscopic level.
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Affiliation(s)
- Matthias Ochs
- Institute of Anatomy, Experimental Morphology Unit, University of Bern, Switzerland.
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Ochs M, Schüttler M, Stichtenoth G, Herting E. Morphological alterations of exogenous surfactant inhibited by meconium can be prevented by dextran. Respir Res 2006; 7:86. [PMID: 16756655 PMCID: PMC1489943 DOI: 10.1186/1465-9921-7-86] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Accepted: 06/06/2006] [Indexed: 02/07/2023] Open
Abstract
Background Surfactant dysfunction due to inhibition is involved in the pathophysiology of meconium aspiration syndrome. Dextran addition has been shown to reverse exogenous surfactant inactivation by meconium, but the precise mechanisms and the morphological correlate of this effect are yet unknown. Morphological surfactant analysis by transmission electron microscopy (TEM) and stereology allows the differentiation of active (large aggregates = LA) and inactive (small aggregates = SA) subtypes. Methods To determine the in vitro effects of meconium and dextran addition on the morphology of a modified porcine natural surfactant (Curosurf), Curosurf samples were either incubated alone or together with meconium or with meconium and dextran, fixed and processed for TEM. Volume fractions of surfactant subtypes [lamellar body-like forms (LBL), multilamellar vesicles (MV), unilamellar vesicles (UV)] were determined stereologically. Results All preparations contained LBL and MV (corresponding to LA) as well as UV (corresponding to SA). The volume fraction of UV increased with addition of meconium and decreased with further addition of dextran. Correspondingly, the UV/(LBL+MV) ratio (resembling the SA/LA ratio) increased when meconium was added and decreased when dextran was added to the surfactant-meconium mixture. Conclusion Meconium causes alterations in the ultrastructural composition of Curosurf that can be visualized and analyzed by TEM and stereology. These alterations resemble an increase in the SA/LA ratio and are paralleled by an increase in minimum surface tension. Dextran prevents these effects and may therefore be a useful additive to exogenous surfactant preparations to preserve their structural and functional integrity, thereby improving their resistance to inactivation.
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Affiliation(s)
- Matthias Ochs
- Institute of Anatomy, Experimental Morphology, University of Bern, Baltzerstrasse 2, CH-3012 Bern, Switzerland
- Department of Anatomy, Division of Electron Microscopy, University of Göttingen, Kreuzbergring 36, D-37075 Göttingen, Germany
| | - Markus Schüttler
- Department of Anatomy, Division of Electron Microscopy, University of Göttingen, Kreuzbergring 36, D-37075 Göttingen, Germany
| | - Guido Stichtenoth
- Department of Pediatrics, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Egbert Herting
- Department of Pediatrics, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
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Shargall Y, Guenther G, Ahya VN, Ardehali A, Singhal A, Keshavjee S. Report of the ISHLT Working Group on Primary Lung Graft Dysfunction Part VI: Treatment. J Heart Lung Transplant 2005; 24:1489-500. [PMID: 16210120 DOI: 10.1016/j.healun.2005.03.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Revised: 02/23/2005] [Accepted: 03/14/2005] [Indexed: 10/25/2022] Open
Affiliation(s)
- Yaron Shargall
- Division of Thoracic Surgery, Toronto General Hospital, Toronto, Ontario, Canada
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Schmiedl A, Tschernig T, Brasch F, Pabst R, Bargsten G. Decrease of the surface fraction of surfactant proteins containing clara cells and type II pneumocytes in a rat asthma model. ACTA ACUST UNITED AC 2005; 56:265-72. [PMID: 15816355 DOI: 10.1016/j.etp.2004.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In asthma surfactant proteins (SP) might differ in distribution and composition and thus play a role in pathophysiology of this disease. Therefore, the well-established animal model of ovalbumin sensitized and challenged rats were used to study the distribution of surfactant proteins in Clara cells and type II pneumocytes. Serial sections of paraffin embedded lung tissue were sequentially immunostained by the avidin-biotin-peroxidase complex (ABC) technique. Antisera against SP-A, SP-B and Clara cell specific protein (CC10) were used. We determined stereologically' the surface fraction of immunolabelled cells and semiquantitatively the percentage of test fields containing labelled alveolar macrophages. In allergen sensitized and provocated rat lungs: (1) the surface fraction of SP-A and SP-B positive Clara cells was significantly reduced, (2) the surface fraction of Clara cells stained with CC10 was coincided with controls, (3) the surface fraction of SP-A and not of SP-B possitive type II pneumocytes decreased significantly, (4) a significantly higher percentage of test fields with SP-A labelled alveolar macrophages was evaluated. Thus, in this animal model of asthma the inflammatory process after allergen challenge is accompanied by alterations in the distribution patterns of SP in Clara cells and type II pneumocytes.
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Affiliation(s)
- Andreas Schmiedl
- Department I, Centre of Anatomy, Hannover Medical School, Hannover, Germany.
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Abstract
Better understanding of the mechanisms of ischemia-reperfusion injury, improvement in the technique of lung preservation, and the recent introduction of a new preservation solution specifically developed for the lungs have helped to reduce the incidence of primary graft dysfunction after lung transplantation. Currently, the limitation in extending the ischemic time is more often related to the increasing use of non-ideal lung donors rather than to poor lung preservation. In this review, we have focused our attention on the experimental and clinical work performed to optimize the methods of lung preservation from the time of retrieval to the period of reperfusion after graft implantation.
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Affiliation(s)
- Marc de Perrot
- Toronto Lung Transplant Program, Toronto General Hospital, University of Toronto, Toronto, Canada
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Abstract
Pulmonary surfactant is a mixture of lipids, mostly phospholipids, and proteins that allows for breathing with minimal effort. The current chapter discusses the metabolism of the phospholipids of this material. Surfactant phospholipids are synthesized in the type II epithelial cells of the lung. The lipids and surfactant proteins are assembled in intracellular storage organelles, called lamellar bodies, and are subsequently secreted into the alveolar space. Within this extracellular space surfactant undergoes several transformations. First the lamellar bodies unravel to form a highly organized lattice-like lipid:protein structure tubular myelin. Second, the organized structures, in particular tubular myelin, adsorb to form a lipid at the air-liquid interface of the alveoli. It is, in fact, this surface tension reducing film that is responsible for the physiological role of surfactant, to prevent lung collapse and allow ease of inflation. Third, the surface film is converted to a small vesicular form. Finally, these small vesicles are taken-up by the type II cells for recycling and degradation and by alveolar macrophages for degradation.
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Affiliation(s)
- Ruud Veldhuizen
- Departments of Medicine and Physiology and Pharmacology, Lawson Health Research Institute, London, ON, N6A 4V2, Canada
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Fehrenbach A, Bube C, Hohlfeld JM, Stevens P, Tschernig T, Hoymann HG, Krug N, Fehrenbach H. Surfactant homeostasis is maintained in vivo during keratinocyte growth factor-induced rat lung type II cell hyperplasia. Am J Respir Crit Care Med 2003; 167:1264-70. [PMID: 12574070 DOI: 10.1164/rccm.200112-132oc] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Keratinocyte growth factor (KGF) induces transient proliferation of alveolar type II cells (AEII) associated with surfactant alterations. To test the hypothesis that homeostasis of intracellular phospholipid stores is maintained under KGF-induced hyperplasia, we (1) collected tissue from adult rat lungs, fixed for light and electron microscopy 3 days after intratracheal instillation of 5 mg recombinant human (rHu) KGF/kg body weight or phosphate-buffered saline (PBS), and from untreated control animals (five animals/group) for design-based stereology of AEII and lamellar body (LB) ultrastructure; and (2) we analyzed uptake and distribution of instilled radiolabeled phospholipids. After rHuKGF, AEII-coverage of alveolar walls (PBS:8.3 +/- 3.0%; rHuKGF:30.6 +/- 4.8%) and number of AEII/ml lung volume (PBS:28.5 +/- 6.5 x 10(6); rHuKGF:48.2 +/- 5.8 x 10(6)) were increased (p < 0.008). Number (PBS:97 +/- 25; rHuKGF:54 +/- 7) and volume (PBS:45.3 +/- 13.8 microm(3); rHuKGF:21.0 +/- 4.7 microm(3)) of LBs per cell were decreased (p < 0.008), but not total amount/ml lung volume (PBS:128 +/- 46. 4 x 10(7) microm(3); rHuKGF:103 +/- 34. 7 x 10(7) microm(3)). This was paralleled by a shift to larger LBs. After rHuKGF, radiolabeled phospholipids accumulated in whole lung tissue relative to lavage fluid (p < 0.01). However, less radiolabel was incorporated per cell (p < 0.01). We conclude that under rHuKGF-induced AEII proliferation intracellular surfactant was decreased per single cell, whereas a constant amount was maintained per unit lung volume. We suggest that surfactant homeostasis is regulated at the level of phospholipid transport processes, for example, secretion and reuptake.
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Affiliation(s)
- Antonia Fehrenbach
- Division of Electron Microscopy, Center of Anatomy, University of Göttingen, Göttingen, Germany
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de Perrot M, Liu M, Waddell TK, Keshavjee S. Ischemia-reperfusion-induced lung injury. Am J Respir Crit Care Med 2003; 167:490-511. [PMID: 12588712 DOI: 10.1164/rccm.200207-670so] [Citation(s) in RCA: 664] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Ischemia-reperfusion-induced lung injury is characterized by nonspecific alveolar damage, lung edema, and hypoxemia occurring within 72 hours after lung transplantation. The most severe form may lead to primary graft failure and remains a significant cause of morbidity and mortality after lung transplantation. Over the past decade, better understanding of the mechanisms of ischemia-reperfusion injury, improvements in the technique of lung preservation, and the development of a new preservation solution specifically for the lung have been associated with a reduction in the incidence of primary graft failure from approximately 30 to 15% or less. Several strategies have also been introduced into clinical practice for the prevention and treatment of ischemia-reperfusion-induced lung injury with various degrees of success. However, only three randomized, double-blinded, placebo-controlled trials on ischemia-reperfusion-induced lung injury have been reported in the literature. In the future, the development of new agents and their application in prospective clinical trials are to be expected to prevent the occurrence of this potentially devastating complication and to further improve the success of lung transplantation.
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Affiliation(s)
- Marc de Perrot
- Toronto Lung Transplant Program, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
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Veldhuizen RAW, Welk B, Harbottle R, Hearn S, Nag K, Petersen N, Possmayer F. Mechanical ventilation of isolated rat lungs changes the structure and biophysical properties of surfactant. J Appl Physiol (1985) 2002; 92:1169-75. [PMID: 11842055 DOI: 10.1152/japplphysiol.00697.2001] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mechanical ventilation is an essential but potentially harmful therapeutic intervention for patients with acute lung injury. The objective of this study was to investigate the effects of mechanical ventilation on large-aggregate surfactant (LA) structure and function. Isolated rat lungs were randomized to either a nonventilated control group, a relatively noninjuriously ventilated group [1 h, 10 ml/kg tidal volume, 3 cmH(2)O positive end-expiratory pressure (PEEP)], or an injuriously ventilated group (1 h, 20 ml/kg tidal volume, 0 cmH(2)O PEEP). Injurious ventilation resulted in significantly decreased lung compliance compared with the other two groups. LA structure, as determined by electron microscopy, revealed that LA from the injurious group had significantly lower amounts of organized lipid-protein structures compared with LA obtained from the other groups. Analysis of the biophysical properties by using a captive bubble surfactometer demonstrated that adsorption and surface tension reduction were significantly impaired with LA from the injuriously ventilated lungs. We conclude that the injurious mechanical ventilation impairs LA function and that this impairment is associated with significant morphological alterations.
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Affiliation(s)
- Ruud A W Veldhuizen
- Lawson Health Research Institute and Department of Physiology, University of Western Ontario, London, Ontario, Canada N6A 4V2.
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Erasmus ME, Hofstede GJH, Petersen AH, Batenburg JJ, Haagsman HP, Oetomo SB, Prop J. SP-A-enriched surfactant for treatment of rat lung transplants with SP-A deficiency after storage and reperfusion. Transplantation 2002; 73:348-52. [PMID: 11884929 DOI: 10.1097/00007890-200202150-00006] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The function of pulmonary surfactant is affected by lung transplantation, contributing to impaired lung transplant function. A decreased amount of surfactant protein-A (SP-A) after reperfusion is believed to contribute to the impaired surfactant function. Surfactant treatment has been shown to improve lung transplant function, but the effect is variable. We investigated whether SP-A enrichment of surfactant improved the efficacy of surfactant treatment in lung transplantation. METHODS Left and right lungs of Lewis rats, inflated with 50% O2, were stored for 20 hr at 8 degrees C. Surfactant in bronchoalveolar lavage fluid from right lungs was investigated after storage (n=6). Left lungs were transplanted into syngeneic recipients and treated with SP-A-deficient surfactant (n=6) or SP-A-enriched surfactant (n=6) just before reperfusion. Air was instilled into untreated lung transplants (n=6). Sham operated (n=4) and normal (n=8) animals served as controls. Lung function was measured during 1 hr of reperfusion; surfactant components in bronchoalveolar lavage fluid were measured after reperfusion. RESULTS After storage the amount of SP-A decreased by 27%, whereas surfactant phospholipids changed minimally. After reperfusion a further decrease of SP-A was paralleled by profound changes in surfactant phospholipids. Lung transplant function, however, remained relatively good. After instillation of SP-A-enriched surfactant, PO2 values were reached that approximated sham control PO2 values, whereas after SP-A-deficient surfactant treatment, the PO2 values did not improve. CONCLUSION Enrichment of surfactant with SP-A for treatment of lung transplants improves the efficacy of surfactant treatment.
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Affiliation(s)
- Michiel E Erasmus
- Department of Cardiopulmonary Surgery, Research Division, University Hospital Groningen, Groningen, The Netherlands
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Ochs M, Fehrenbach H, Richter J. Ultrastructure of canine type II pneumocytes during hypothermic ischemia of the lung: a study by means of conventional and energy filtering transmission electron microscopy and stereology. ACTA ACUST UNITED AC 2001; 263:118-26. [PMID: 11360229 DOI: 10.1002/ar.1084] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Alterations in pulmonary surfactant have been reported to be associated with ischemia/reperfusion injury in experimental and clinical lung transplantation. It is unknown whether these alterations are due to damage to surfactant synthesizing type II pneumocytes during hypothermic ischemic storage. The aim of the present study was to examine the effects of hypothermic ischemic storage of the lung on canine type II pneumocytes by means of conventional (CTEM) and energy filtering TEM (EFTEM) and stereology. The lungs of 18 dogs were fixed for TEM immediately after cardiac arrest (6 double lungs) and after storage in Tutofusin at 4 degrees C for 20 min, 4 hr, 8 hr, and 12 hr (6 single lungs, respectively). Using a systematic uniform random sampling scheme, type II pneumocytes were analyzed qualitatively and stereologically. The relative phosphorus content of cell organelles, especially the surfactant containing lamellar bodies, was investigated by EFTEM. By CTEM, no major qualitative alterations could be observed in type II pneumocytes of the experimental groups. Stereologically, no significant changes in the volume densities or the volume-to-surface ratios of type II pneumocytes and their lamellar bodies were found. By EFTEM, the highest intracellular phosphorus signals were recorded over lamellar bodies in all experimental groups. No changes in the phosphorus signals were observed during ischemia. These results indicate that the ultrastructure of canine type II pneumocytes and their lamellar bodies is not affected by hypothermic ischemia of the lung up to 12 hr. Structural preservation of intracellular surfactant is possible during prolonged ischemic lung storage.
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Affiliation(s)
- M Ochs
- Department of Anatomy, Division of Electron Microscopy, Georg-August-University, Göttingen, Germany.
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