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Im D, Shi W, Driscoll B. Pediatric Acute Respiratory Distress Syndrome: Fibrosis versus Repair. Front Pediatr 2016; 4:28. [PMID: 27066462 PMCID: PMC4811965 DOI: 10.3389/fped.2016.00028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/15/2016] [Indexed: 01/11/2023] Open
Abstract
Clinical and basic experimental approaches to pediatric acute lung injury (ALI), including acute respiratory distress syndrome (ARDS), have historically focused on acute care and management of the patient. Additional efforts have focused on the etiology of pediatric ALI and ARDS, clinically defined as diffuse, bilateral diseases of the lung that compromise function leading to severe hypoxemia within 7 days of defined insult. Insults can include ancillary events related to prematurity, can follow trauma and/or transfusion, or can present as sequelae of pulmonary infections and cardiovascular disease and/or injury. Pediatric ALI/ARDS remains one of the leading causes of infant and childhood morbidity and mortality, particularly in the developing world. Though incidence is relatively low, ranging from 2.9 to 9.5 cases/100,000 patients/year, mortality remains high, approaching 35% in some studies. However, this is a significant decrease from the historical mortality rate of over 50%. Several decades of advances in acute management and treatment, as well as better understanding of approaches to ventilation, oxygenation, and surfactant regulation have contributed to improvements in patient recovery. As such, there is a burgeoning interest in the long-term impact of pediatric ALI/ARDS. Chronic pulmonary deficiencies in survivors appear to be caused by inappropriate injury repair, with fibrosis and predisposition to emphysema arising as irreversible secondary events that can severely compromise pulmonary development and function, as well as the overall health of the patient. In this chapter, the long-term effectiveness of current treatments will be examined, as will the potential efficacy of novel, acute, and long-term therapies that support repair and delay or even impede the onset of secondary events, including fibrosis.
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Affiliation(s)
- Daniel Im
- Pediatric Critical Care Medicine, Department of Pediatrics, The Saban Research Institute, Children's Hospital Los Angeles, University of Southern California , Los Angeles, CA , USA
| | - Wei Shi
- Developmental Biology and Regenerative Medicine Program, Department of Surgery, The Saban Research Institute, Children's Hospital Los Angeles, University of Southern California , Los Angeles, CA , USA
| | - Barbara Driscoll
- Developmental Biology and Regenerative Medicine Program, Department of Surgery, The Saban Research Institute, Children's Hospital Los Angeles, University of Southern California , Los Angeles, CA , USA
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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.
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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.
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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]
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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.
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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.
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Russo TA, Wang Z, Davidson BA, Genagon SA, Beanan JM, Olson R, Holm BA, Knight PR, Chess PR, Notter RH. Surfactant dysfunction and lung injury due to the E. coli virulence factor hemolysin in a rat pneumonia model. Am J Physiol Lung Cell Mol Physiol 2007; 292:L632-43. [PMID: 17341765 DOI: 10.1152/ajplung.00326.2006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study tests the hypothesis that the virulence factor hemolysin (Hly) expressed by extraintestinal pathogenic Escherichia coli contributes to surfactant dysfunction and lung injury in a rat model of gram-negative pneumonia. Rats were instilled intratracheally with CP9 (wild type, Hly-positive), CP9hlyA (Hly-minus), CP9/pEK50 (supraphysiological Hly), or purified LPS. At 6 h postinfection, rats given CP9 had a decreased percentage content of large surfactant aggregates in cell-free bronchoalveolar lavage (BAL), decreased large aggregate surface activity, decreased Pa(O2)/FiO2) ratio, increased BAL albumin/protein levels, and increased histological evidence of lung injury compared with rats given CP9hlyA or LPS. In addition, rats given CP9/pEK50 or CP9 had decreased large aggregate surface activity, decreased Pa(O2)/FiO2) ratios, and increased BAL albumin/protein levels at 2 h postinfection compared with rats given CP9hlyA. The severity of permeability lung injury based on albumin/protein levels in BAL at 2 h was ordered as CP9/pEK50 > CP9 > CP9hlyA > normal saline controls. Total lung titers of bacteria were increased at 6 h in rats given CP9 vs. CP9hlyA, but bacterial titers were not significantly different at 2 h, indicating that increased surfactant dysfunction and lung injury were associated with Hly as opposed to bacterial numbers per se. Further studies in vitro showed that CP9 could directly lyse transformed pulmonary epithelial cells (H441 cells) but that indirect lysis of H441 cells secondary to Hly-induced neutrophil lysis did not occur. Together, these data demonstrate that Hly is an important direct mediator of surfactant dysfunction and lung injury in gram-negative pneumonia.
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Affiliation(s)
- Thomas A Russo
- Department of Medicine, The Witebsky Center for Microbial Pathogenesis, NY, USA.
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Becker MJ, De Marie S, Fens MHAM, Haitsma JJ, Verbrugh HA, Lachmann B, Bakker-Woudenberg IAJM. Pathophysiology of unilateral pulmonary aspergillosis in an experimental rat model. Med Mycol 2006; 44:133-9. [PMID: 16519016 DOI: 10.1080/13693780500271749] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Because little is known about the pathophysiology of invasive pulmonary aspergillosis (IPA), we examined changes in pulmonary and general physiology during this disease in an animal model. In a model of fatal left-sided IPA, 19 persistently neutropenic rats were monitored for clinical signs including body temperature, body weight and respiratory distress. A separate group of nine rats with IPA was used for measurements of arterial blood pressure, arterial O2 and CO2 pressure, lung compliance and surfactant function. Body temperature and body weight decreased, whereas respiratory distress increased during progression of the disease. Compared to uninfected controls, in rats with IPA arterial blood pressure and lung compliance were significantly lower, and left lung minimal surface tension was significantly higher. Right lung surfactant function was not affected. Arterial O2 and CO2 pressures were not different between rats with IPA and uninfected controls. Infection with Aspergillus fumigatus in neutropenic rats resulted in hypothermia, body weight loss and respiratory distress. Loss of left lung function was probably compensated by the uninfected right lung, even in a late stage of the disease. Circulatory failure was a major feature in the terminal phase of the infection.
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Affiliation(s)
- Martin J Becker
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC-University Medical Center Rotterdam, The Netherlands.
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Surfactant Therapy: Beyond a Rescue Therapy for ARDS. Intensive Care Med 2003. [DOI: 10.1007/978-1-4757-5548-0_32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Gan X, Jarstrand C, Herting E, Berggren P, Robertson B. Effect of surfactant and specific antibody on bacterial proliferation and lung function in experimental pneumococcal pneumonia. Int J Infect Dis 2001; 5:9-18. [PMID: 11285153 DOI: 10.1016/s1201-9712(01)90042-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE To investigate the effect of surfactant and specific antibody on bacterial proliferation in experimental pneumococcal pneumonia. METHODS Near-term newborn rabbits received a standard dose (10(7)) of type 3 pneumococci via the airways. Control animals were sacrificed 1 minute later. Other animals were ventilated for 5 hours and treated via the tracheal cannula with surfactant (Curosurf 200 mg/kg), a mixture of surfactant and a polyclonal antipneumococcal antibody, the antibody without surfactant, or saline. RESULTS There was a significant bacterial proliferation in lung tissue in all animals ventilated for 5 hours. Bacterial growth, expressed as log10 colony forming units (CFU) per gram of lung tissue was less prominent in animals treated with a mixture of surfactant and specific antibody than in animals treated with antibody alone (median, 7.51, range, 6.80--7.70 vs. median, 7.92, range, 7.07--8.50; P < 0.05). Dynamic lung-thorax compliance was improved with surfactant or surfactant plus antibody in comparison with saline or antibody alone. CONCLUSIONS The data suggest that the suppressive effect of the antibody on bacterial proliferation becomes evident only when surfactant is administered together with the antibody.
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Affiliation(s)
- X Gan
- Division for Experimental Perinatal Pathology, Department of Woman and Child Health, Karolinska Hospital, Stockholm, Sweden
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Hallman M, Glumoff V, Rämet M. Surfactant in respiratory distress syndrome and lung injury. Comp Biochem Physiol A Mol Integr Physiol 2001; 129:287-94. [PMID: 11369552 DOI: 10.1016/s1095-6433(01)00324-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A deficiency in alveolar surfactant due to immaturity of alveolar type II epithelial cells causes respiratory distress syndrome (RDS). In contrast to animals, the fetal maturation of surfactant in human lungs takes place before term, exceptionally large quantities of surfactant accumulating in the amniotic fluid. The antenatal development of surfactant secretion is very variable but corresponds closely to the risk of RDS. The variation in SP-A and SP-B genes, race, sex and perinatal complications influence susceptibility to RDS. Surfactant therapy has improved the prognosis of RDS remarkably. Abnormalities in alveolar or airway surfactant characterize many lung and airway diseases. In the acute respiratory distress syndrome, deficiencies in surfactant components (phospholipids, SP-B, SP-A) are evident, and may be caused by pro-inflammatory cytokines (IL-1, TNF) that decrease surfactant components. The resultant atelectasis localizes the disease, possibly allowing healing (regeneration, increase in surfactant). In the immature fetus, cytokines accelerate the differentiation of surfactant, preventing RDS. After birth, however, persistent inflammation is associated with low SP-A and chronic lung disease. A future challenge is to understand how to inhibit or redirect the inflammatory response from tissue destruction and poor growth towards normal lung development and regeneration.
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Affiliation(s)
- M Hallman
- Department of Pediatrics, University of Oulu, 90220, Oulu, Finland
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Wright TW, Notter RH, Wang Z, Harmsen AG, Gigliotti F. Pulmonary inflammation disrupts surfactant function during Pneumocystis carinii pneumonia. Infect Immun 2001; 69:758-64. [PMID: 11159965 PMCID: PMC97949 DOI: 10.1128/iai.69.2.758-764.2001] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During Pneumocystis carinii pneumonia (PCP) in mice, the degree of pulmonary inflammation correlates directly with the severity of lung function deficits. Therefore, studies were undertaken to determine whether the host inflammatory response contributes to PCP-related respiratory impairment, at least in part, by disrupting the pulmonary surfactant system. Protein and phospholipid content and surfactant activity were measured in the lavage fluid of infected mice in either the absence or presence of an inflammatory response. At 9 weeks postinfection with P. carinii, nonreconstituted SCID mice exhibited no signs of pulmonary inflammation, respiratory impairment, or surfactant dysfunction. Lavage fluid obtained from these mice had protein/phospholipid (Pr/PL) ratios (64% +/- 4.7%) and minimum surface tension values (4.0 +/- 0.9 mN/m) similar to those of P. carinii-free control mice. However, when infected SCID mice were immunologically reconstituted, an intense inflammatory response ensued. Pr/PL ratios (218% +/- 42%) and minimum surface tension values (27.2 +/- 2.7 mN/m) of the lavage fluid were significantly elevated compared to those of the lavage fluid from infected, nonreconstituted mice (P < 0.05). To examine the specific role of CD8(+) T-cell-mediated inflammation in surfactant dysfunction during PCP, mice with defined T-cell populations were studied. P. carinii-infected, CD4(+)-depleted mice had elevated lavage fluid Pr/PL ratios (126% +/- 20%) and elevated minimum surface tension values (16.3 +/- 1.0 mN/m) compared to normal mice (P < 0.05). However, when infected mice were additionally depleted of CD8(+) cells, Pr/PL ratios were normal and surfactant activity was improved. These findings demonstrate that the surfactant pathology associated with PCP is related to the inflammatory process rather than being a direct effect of P. carinii. Moreover, CD8(+) lymphocytes are involved in the mechanism leading to surfactant dysfunction.
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Affiliation(s)
- T W Wright
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
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Waugh JB, Op't Holt TB, Olson LE, Gadek JE, Clanton TL. Surfactant treatment impairs gas exchange in a canine model of acute lung injury. Crit Care Med 2000; 28:2887-92. [PMID: 10966266 DOI: 10.1097/00003246-200008000-00033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED The effectiveness of surfactant (SURF) treatment in acute lung injury in the adult is controversial. In this study, we tested the effectiveness of early surfactant treatment in a commonly used animal model of acute lung injury, phorbol-myristate acetate (PMA), to see if it would attenuate the progression of lung injury. We measured the effect on lung compliance and whether positive end-expiratory pressure (PEEP) (10 cm H2O) during SURF administration had a synergistic effect. METHODS Four groups of anesthetized dogs were studied: a) normals; b) PMA injury only; c) PMA injury + SURF; and d) PMA + SURF + PEEP. Lung injury was induced with 25-30 microg/kg of PMA. Responses were measured over 7 hrs. Surfactant was administered in the form of Survanta, 4 x 25 mg/kg doses via tracheal instillation 2.5 hrs after PMA. For the group receiving PEEP, 10 cm H2O PEEP was begun 1.5 hrs after PMA, 1 hr before SURF. Postmortem, the left lung was excised and inflated three times to total lung capacity (volume at 30 cm H2O) and expiratory compliance was measured with 25-100 mL volume increments. The trachea was then clamped and trapped volume was determined by water displacement. RESULTS PMA-induced lung injury significantly reduced expiratory compliance and total lung capacity (p < .05 from normal). Wet/dry lung weights did not differ between groups. SURF without PEEP further decreased lung compliance as compared with PMA only. CONCLUSIONS SURF administration after PMA injury causes marked reductions in lung compliance when no PEEP is coadministered. However, the loss of static expiratory lung compliance appears partly ameliorated by application of PEEP + SURF. Given that tracheal instillation of SURF is known to acutely elevate lung impedance in the first few hours after administration, coadministration of PEEP appears to be critically important in counteracting these early effects of surfactant instillation on the lung.
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Affiliation(s)
- J B Waugh
- Critical & Diagnostic Care Department, University of Alabama, Birmingham, USA
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Tang X, Lasbury ME, Davidson DD, Bartlett MS, Smith JW, Lee CH. Down-regulation of GATA-2 transcription during Pneumocystis carinii infection. Infect Immun 2000; 68:4720-4. [PMID: 10899878 PMCID: PMC98420 DOI: 10.1128/iai.68.8.4720-4724.2000] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2000] [Accepted: 05/05/2000] [Indexed: 11/20/2022] Open
Abstract
Differences in gene expression between Pneumocystis carinii-infected and noninfected rats were examined. Total RNA was isolated from homogenized rat lungs and then subjected to differential display with combinations of oligo(dT) and various arbitrary PCR primers. Approximately 50 differentially expressed bands were observed. Several of these DNA bands were isolated, reamplified, and cloned. The cloned DNA fragments were used as probes to perform Northern hybridization on RNA from P. carinii-infected and noninfected rat lungs. One clone was found to react with a 3-kb mRNA from noninfected but not from P. carinii-infected rat lung, suggesting that the gene represented by this clone was down-regulated during P. carinii infection. The nucleotide sequence of this clone was determined and found to be 97% homologous to the mouse GATA-2 transcription factor. In situ hybridization using RNA probes derived from this clone revealed that alveolar macrophages, resident lung monocytes, and bronchial epithelial cells express the GATA-2 gene in the lung.
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Affiliation(s)
- X Tang
- Departments of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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Herting E, Gan X, Rauprich P, Jarstrand C, Robertson B. Combined treatment with surfactant and specific immunoglobulin reduces bacterial proliferation in experimental neonatal group B streptococcal pneumonia. Am J Respir Crit Care Med 1999; 159:1862-7. [PMID: 10351931 DOI: 10.1164/ajrccm.159.6.9810047] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Neonates suffering from group B streptococcal (GBS) pneumonia often lack type-specific opsonizing antibodies. We studied the influence of combined intratracheal treatment with surfactant and a specific antibacterial polyclonal antibody (IgG fraction) on bacterial proliferation and lung function in an animal model of GBS pneumonia. Near-term newborn rabbits received an intratracheal injection of either the specific IgG antibody, nonspecific IgG, surfactant, a mixture of surfactant and the antibody, or 0.9% saline. At 30 min the rabbits were infected with a standard dose (10(8)) of the encapsulated GBS strain 090 Ia. After 5 h of mechanical ventilation the mean estimated increase in bacterial number in lung homogenate (log10 colonies/g) was 0.76 in the antibody group, 0.92 in the nonspecific IgG group, 0.55 in the surfactant group, and 1.29 in the saline group. A mean decrease in bacterial number (-0.05) was observed in the group that received combined treatment with surfactant and antibody (p < 0.05 versus all other groups). Lung-thorax compliance was significantly higher in both groups of surfactant-treated animals compared with saline or IgG treatment. We conclude that in experimental neonatal GBS pneumonia combined treatment with surfactant and a specific immunoglobulin against GBS reduced bacterial proliferation more effectively than either treatment alone.
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Affiliation(s)
- E Herting
- Department of Pediatrics, University of Göttingen, Göttingen, Germany.
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Martin WJ, Wright JR. Pneumocystis carinii pneumonia and pulmonary surfactant. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1999; 133:406-7. [PMID: 10235122 DOI: 10.1016/s0022-2143(99)90016-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Beers MF, Atochina EN, Preston AM, Beck JM. Inhibition of lung surfactant protein B expression during Pneumocystis carinii pneumonia in mice. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1999; 133:423-33. [PMID: 10235125 DOI: 10.1016/s0022-2143(99)90019-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The pathogenesis of Pneumocystis carinii pneumonia (PCP) suggests an important role for dysfunction of the pulmonary surfactant system in the hypoxemic respiratory insufficiency associated with this infection. Surfactant protein B (SP-B) is a hydrophobic protein shown to be essential for normal surfactant function in vivo. Therefore, we hypothesized that the inhibition of SP-B expression occurs during PCP, and we tested this hypothesis in two immunodeficient animal models. PCP was induced in C.B-17 scid/scid mice by intratracheal inoculation of P. carinii organisms. Infected lung homogenates, obtained at time points up to 6 weeks after inoculation, were analyzed for SP-B and mRNA content. When a comparison was made with uninfected scid controls, the densitometric quantitation of Western blots of lung homogenates demonstrated significant reductions in 8 kd SP-B in mice infected with P. carinii 4 weeks after inoculation (16% of the control value). Northern blot analysis showed a concomitant decrease in SP-B mRNA to 24% of the control level. The decrease in SP-B and mRNA levels in lung homogenates of infected mice was reflected in lower SP-B levels in the surfactant. An enzyme-linked immunosorbent assay for the SP-B level in surfactant prepared from bronchoalveolar lavage samples of infected scid mice demonstrated a significant reduction in alveolar SP-B content (45% of the control value). In contrast to the results with SP-B, neither the SP-A protein content nor the mRNA level was significantly altered by PCP infection. To confirm these observations, SP-B expression was studied in an additional animal model of PCP. The SP-B content of lung homogenates from BALB/c mice depleted of CD4+ T cells and infected with P. carinii was also reduced (51% of the control value). We conclude that P. carinii induces selective inhibition of the expression of SP-B in two mouse models of PCP and that this down-regulation is mediated at the level of mRNA expression. Therefore, an acquired deficiency of SP-B is likely to be an important contributor to the pathogenesis of hypoxemic respiratory failure that is observed in patients with PCP.
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Affiliation(s)
- M F Beers
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104-6068, USA
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Kaufman B, Dhar P. Acute Respiratory Distress Syndrome: Potential Pharmacologic Interventions. J Pharm Pract 1998. [DOI: 10.1177/089719009801100606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The mortality of the acute respiratory distress syndrome (ARDS) remains high despite advances in supportive care of ARDS and in the understanding of the pathogenesis. Numerous inflammatory mediators including reactive oxygen species, arachidonic acid metabolites, and growth factors, are present in the circulation of patients with or at risk for developing this syndrome and play a key pathophysiologic role in the development of lung injury. Pharmacologic therapy is being evaluated to: 1) support the failing lung by improving gas exchange; 2) interrupt the mediator-induced mechanisms of inflammation and injury. Although none of these experimental therapies has yet been proven to improve survival in well conducted prospective, randomized, double-blind, controlled clinical trials, many have demonstrated improvement in physiologic function. These results have helped lay the groundwork for future advances in this field.
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Affiliation(s)
| | - Panchali Dhar
- Department of Anesthesiology, New York University School of Medicine, 560 First Avenue, New York, NY 10016
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Prévost MC, Escamilla R, Aliouat EM, Ceré N, Coudert P, Dei-Cas E. Pneumocystosis pathophysiology. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 1998; 22:123-8. [PMID: 9792070 DOI: 10.1111/j.1574-695x.1998.tb01196.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M C Prévost
- INSERM U326, Hôpital Purpan, Toulouse, France.
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Prevost MC, Aliouat EM, Escamilla R, Dei-Cas E. Pneumocystosis in humans or in corticosteroid-untreated animal models: interactions between pulmonary surfactant changes and Pneumocystis carinii in vivo or in vitro growth. J Eukaryot Microbiol 1997; 44:58S. [PMID: 9508443 DOI: 10.1111/j.1550-7408.1997.tb05778.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Nilsson K, John J, Lachmann B, Robertson B, Wollmer P. Pulmonary clearance of 99mTc-DTPA in experimental surfactant dysfunction treated with surfactant instillation. Acta Anaesthesiol Scand 1997; 41:297-303. [PMID: 9062616 DOI: 10.1111/j.1399-6576.1997.tb04682.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Breakdown of the alveolo-capillary barrier is a characteristic feature of respiratory distress syndrome. Restoration of alveolo-capillary barrier function may be an important aspect of surfactant replacement therapy. We examined the effect of surfactant instillation on alveolo-capillary barrier function in an experimental model of surfactant dysfunction by measuring pulmonary clearance of 99mTc-DTPA. METHODS Nineteen rabbits were tracheotomized and mechanically ventilated. Surfactant dysfunction was induced by administration of a synthetic detergent in aerosol form. Detergent was given to 13 rabbits; seven rabbits were then treated with instillation of natural surfactant, whereas six rabbits received saline. Six rabbits were used as untreated controls. An aerosol of 99mTc-DTPA was administered to all animals and the pulmonary clearance was measured with a gamma camera. RESULTS 99mTc-DTPA cleared from the lungs with a half-life of 71 +/- 22 min in the control animals, 21.4 +/- 7.4 min in the surfactant-treated animals and 5.8 +/- 1.5 min in the saline-treated animals. The difference in half-life between groups was highly significant (P < 0.001). There was no change in arterial oxygenation or compliance in controls or in animals treated with saline. In animals treated with surfactant, a small transient reduction in arterial oxygen tension and a more long-standing reduction in compliance were observed. CONCLUSION Surfactant treatment thus significantly attenuated the effect of detergent treatment but did not restore alveolo-capillary transfer of 99mTc-DTPA to normal.
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Affiliation(s)
- K Nilsson
- Department of Clinical Physiology, University of Lund, St Göran's Hospital, Stockholm, Sweden
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Herting E, Sun B, Jarstrand C, Curstedt T, Robertson B. Surfactant improves lung function and mitigates bacterial growth in immature ventilated rabbits with experimentally induced neonatal group B streptococcal pneumonia. Arch Dis Child Fetal Neonatal Ed 1997; 76:F3-8. [PMID: 9059178 PMCID: PMC1720614 DOI: 10.1136/fn.76.1.f3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
AIMS To study the influence of surfactant on lung function and bacterial proliferation in immature newborn rabbits with experimental group B streptococcal (GBS) pneumonia. METHODS Preterm rabbit fetuses (gestational age 28 days) underwent tracheotomy and were mechanically ventilated in a warmed body plethysmograph that permitted measurement of lung-thorax compliance. Fifteen minutes after the onset of ventilation the animals received either GBS or saline intratracheally; at 30 minutes, a bolus of saline or 200 mg/kg of a porcine surfactant (Curosurf) was administered via the airway. Bacterial proliferation was evaluated in lung homogenate at the end of the experiments and the results expressed as mean log10 cfu/g lung (SD). Animals receiving only saline (n = 20) or saline and surfactant (n = 20) served as controls. RESULTS The average survival time was about three hours in all groups. Infected animals receiving surfactant (n = 22) had significantly less bacterial growth (9.09 (0.45) vs 9.76 (0.91)) and improved lung function (compliance: 0.61 (0.14) vs 0.34 (0.19) ml/kg. cm H2O) than infected rabbits receiving saline at 30 minutes (n = 22). CONCLUSION Surfactant improves lung function and mitigates bacterial growth in preterm rabbits infected with group B streptococci.
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Affiliation(s)
- E Herting
- Department of Paediatrics, University of Göttingen, Germany
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22
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Abstract
We describe two infants suffering from severe pneumonia caused by respiratory syncytial virus (RSV) infection and needing mechanical ventilation with both high ventilator settings and a high fraction of inspired oxygen. The severity of the respiratory failure and the possibility of decreased and/or altered surfactant production led us to treat these infants with intratracheal instillation of natural surfactant. This resulted in an improvement of lung compliance and a decrease in the amount of oxygen required to maintain acceptable oxygen saturations. Intratracheal surfactant instillation might, therefore, be useful in the treatment of severe RSV pneumonia.
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Affiliation(s)
- G D Vos
- Department of Pediatrics, University Hospital Maastricht, The Netherlands
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23
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van't Veen A, Mouton JW, Gommers D, Lachmann B. Pulmonary surfactant as vehicle for intratracheally instilled tobramycin in mice infected with Klebsiella pneumoniae. Br J Pharmacol 1996; 119:1145-8. [PMID: 8937717 PMCID: PMC1915913 DOI: 10.1111/j.1476-5381.1996.tb16016.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
1. The use of pulmonary surfactant has been proposed as a vehicle for antibiotic delivery to the alveolar compartment of the lung. This study investigated survival rates of mice with a respiratory Klebsiella pneumoniae infection treated intratracheally with tobramycin using a natural exogenous surfactant preparation as vehicle. 2. At day 1 after infection, animals were injected intratracheally with 20 microliters of the following solutions: (1) a mixture of surfactant (500 micrograms) and tobramycin (250 micrograms); (2) tobramycin (250 micrograms) alone; (3) surfactant (500 micrograms) alone; and (4) NaHCO3 buffer (control, sham-treatment). A fifth group received no treatment (control). Deaths were registered every 12 h for 8 consecutive days. 3. The results show an increased survival in the group receiving the surfactant-tobramycin mixture compared to the group receiving tobramycin alone (P < 0.05), the group receiving surfactant alone (P < 0.01) and the control groups (P < 0.01). It is concluded that intratracheal instillation of surfactant-tobramycin is superior to tobramycin alone in protecting animals from death due to a respiratory Klebsiella pneumoniae infection.
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Affiliation(s)
- A van't Veen
- Department of Anaesthesiology, Erasmus University, Rotterdam, The Netherlands
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24
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Affiliation(s)
- M J Kresch
- University of Connecticut Health Center, Division of Neonatology, Farmington 06030-2203, USA
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25
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Song GW, Robertson B, Curstedt T, Gan XZ, Huang WX. Surfactant treatment in experimental Escherichia coli pneumonia. Acta Anaesthesiol Scand 1996; 40:1154-60. [PMID: 8933859 DOI: 10.1111/j.1399-6576.1996.tb05580.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Deterioration of lung function in bacterial pneumonia may in part be due to inactivation of endogenous surfactant. We investigated the effects of surfactant treatment on gas exchange and lung morphology in an experimental model of pneumonia caused by Escherichia coli. METHODS A total of 117 adult rats received via the trachea 2 ml/kg body weight of a standard suspension of Escherichia coli (4 x 10(9) bacteria/ml). After 2-3 days, 31 of the infected animals showed symptoms of respiratory failure with PaO2 < 27 kPa during ventilation with 100% O2. All these animals were kept in a multi-plethysmograph system and ventilated for 45 min with a tidal volume of 6 ml/kg, a frequency of 30/min, an inspiration/expiration ratio of 1:1, and a positive end-expiratory pressure of 0.2 kPa. After 15 min of mechanical ventilation, animals were divided in three treatment groups, receiving via the airways (1) no material, (2) normal saline (2 ml/kg), or (3) Curosurf, 80 mg/ml (2 ml/kg). Ten healthy animals served as controls. Lung-thorax compliance and blood gases were measured 15 and 30 min after surfactant treatment. After the period of ventilation, animals were killed, and the left lung was weighed and fixed in formalin for histological examination. The right lung was washed in situ with normal saline via the tracheal tube. Total phospholipids, and levels of phosphatidylcholine (PC) and protein in lavage fluid were determined. RESULTS In comparison with pre-treatment values, average PaO2 at 30 min was increased by 76% in animals receiving Curosurf (P < 0.01), but did not improve in the other groups. The left lung weight/body weight ratio showed a nearly 3-fold increase in infected animals in comparison with normal controls. There was also a 3-fold increase in the protein content of lung lavage fluid from infected rats, but values for total phospholipids and PC content were unchanged in animals not receiving surfactant. Histological examination of the lungs showed wide-spread non-specific pneumonia in infected animals, but no difference in alveolar air expansion between surfactant-treated and non-treated ones. CONCLUSION Surfactant replacement significantly improves oxygenation in rats with E. coli pneumonia, without affecting lung-thorax compliance during mechanical ventilation or alveolar expansion pattern in lungs fixed by conventional methods.
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Affiliation(s)
- G W Song
- Capital Institute of Pediatrics, Beijing, China
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26
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van 't Veen A, Gommers D, Mouton JW, Kluytmans JA, Krijt EJ, Lachmann B. Exogenous pulmonary surfactant as a drug delivering agent: influence of antibiotics on surfactant activity. Br J Pharmacol 1996; 118:593-8. [PMID: 8762082 PMCID: PMC1909731 DOI: 10.1111/j.1476-5381.1996.tb15442.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
1. It has been proposed to use exogenous pulmonary surfactant as a drug delivery system for antibiotics to the alveolar compartment of the lung. Little, however, is known about interactions between pulmonary surfactant and antimicrobial agents. This study investigated the activity of a bovine pulmonary surfactant after mixture with amphotericin B, amoxicillin, ceftazidime, pentamidine or tobramycin. 2. Surfactant (1 mg ml-1 in vitro and 40 mg ml-1 in vivo) was mixed with 0.375 mg ml-1 amphotericin B, 50 mg ml-1 amoxicillin, 37.5 mg ml-1 ceftazidime, 1 mg ml-1 pentamidine and 2.5 mg ml-1 tobramycin. Minimal surface tension of 50 microliters of the mixtures was measured in vitro by use of the Wilhelmy balance. In vivo surfactant activity was evaluated by its capacity to restore gas exchange in an established rat model for surfactant deficiency. 3. Surfactant deficiency was induced in ventilated rats by repeated lavage of the lung with warm saline until PaO2 dropped below 80 cmH2O with 100% inspired oxygen at standard ventilation settings. Subsequently an antibiotic-surfactant mixture, saline, air, or surfactant alone was instilled intratracheally (4 ml kg-1 volume, n = 6 per treatment) and blood gas values were measured 5, 30, 60, 90 and 120 min after instillation. 4. The results showed that minimal surface tensions of the mixtures were comparable to that of surfactant alone. In vivo PaO2 levels in the animals receiving ceftazidime-surfactant or pentamidine-surfactant were unchanged when compared to the surfactant group. PaO2 levels in animals receiving amphotericin B-surfactant, amoxicillin-surfactant or tobramycin-surfactant were significantly decreased compared to the surfactant group. For tobramycin it was further found that PaO2 levels were not affected when 0.2 M NaHCO3 (pH = 8.3) buffer was used for suspending surfactant instead of saline. 5. It is concluded that some antibiotics affect the in vivo activity of a bovine pulmonary surfactant. Therefore, before using surfactant-antibiotic mixtures in clinical trials, interactions between the two agents should be carefully evaluated.
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Affiliation(s)
- A van 't Veen
- Department of Anaesthesiology, Erasmus University Rotterdam, The Netherlands
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27
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Su TH, Natarajan V, Kachel DL, Moxley MA, Longmore WJ, Martin WJ. Functional impairment of bronchoalveolar lavage phospholipids in early Pneumocystis carinii pneumonia in rats. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1996; 127:263-71. [PMID: 9273359 DOI: 10.1016/s0022-2143(96)90094-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Surfactant abnormalities may contribute to the impairment of gas exchange observed in Pneumocystis carinii pneumonia. Analysis of rat bronchoalveolar lavage (BAL) lipid extracts from normal controls, steroid controls, trimethaprim-sulfamethoxazole (TMP-SMX) controls, TMP-SMX/P. carinii pneumonia controls, and P. carinii pneumonia animals reveal similar total phospholipid and total protein levels. However, there was a marked reduction in phosphatidylglycerol (PG) from the BAL of P. carinii pneumonia rats as compared with control animals, with a decrease from 4.91 +/- 1.29 nmol/mg protein to 0.46 +/- 0.57 nmol/mg protein (p<0.05) and a decrease, as a percent of total phospholipids, from 7.7% +/- 0.88% to 0.91% +/- 0.59% (p<0.001). Furthermore, in vitro surface activities of BAL lipid extracts from control and P. carinii pneumonia rats revealed minimum surface tension increases from 9.38 +/- 1.71 mN/m in controls to 16.36 +/- 0.83 mN/m in P. carinii pneumonia rats (p<0.05) and likewise maximum surface tension increases from 22.14 +/- 4.34 mN/m to 38.57 +/- 2.07 mN/m (p<0.01). Of interest, the surface activity of PG-deficient P. carinii pneumonia BAL lipid extracts is completely restored to that of normal controls by the addition of exogenous PG. These findings suggest that a functionally abnormal surfactant occurs in P. carinii pneumonia and that this may account, in part, for the impairment of gas exchange observed in this disorder.
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Affiliation(s)
- T H Su
- Division of Pulmonary and Critical Care Medicine, Indiana University School of Medicine, Indianapolis, USA
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28
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van 't Veen A, Mouton JW, Gommers D, Kluytmans JA, Dekkers P, Lachmann B. Influence of pulmonary surfactant on in vitro bactericidal activities of amoxicillin, ceftazidime, and tobramycin. Antimicrob Agents Chemother 1995; 39:329-33. [PMID: 7726491 PMCID: PMC162536 DOI: 10.1128/aac.39.2.329] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The influence of a natural pulmonary surfactant on antibiotic activity was investigated to assess the possible use of exogenous surfactant as a vehicle for antibiotic delivery to the lung. The influence of surfactant on the bactericidal activity of amoxicillin was tested against Staphylococcus aureus and Streptococcus pneumoniae, and the influence of surfactant on the activities of ceftazidime and tobramycin was tested against Klebsiella pneumoniae, Pseudomonas aeruginosa, S. aureus, and S. pneumoniae. In vitro antibiotic activity was determined by killing curve studies in media with and without surfactant. Amoxicillin and ceftazidime activities were not changed in the presence of surfactant, except for a decreased killing rate of S. pneumoniae by ceftazidime in medium with additional rabbit serum. In contrast, killing curves with low concentrations of tobramycin (0.25x and 1x the MIC) showed a decreased level of activity of tobramycin against all pathogens tested in the presence of surfactant. With higher tobramycin concentrations (4x the MIC) killing rates were decreased less or were unchanged in the presence of surfactant. Concluding from the results of the study, both amoxicillin and ceftazidime can be combined with surfactant without the loss of activity. For mixing surfactant with tobramycin, dosages should be adjusted to overcome the partial inactivation of tobramycin by surfactant.
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Affiliation(s)
- A van 't Veen
- Department of Anaesthesiology, Erasmus University Rotterdam, The Netherlands
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29
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Slater AJ, Nichani SH, Macrae D, Wilkinson KA, Novelli V, Tasker RC. Surfactant adjunctive therapy for Pneumocystis carinii pneumonitis in an infant with acute lymphoblastic leukaemia. Intensive Care Med 1995; 21:261-3. [PMID: 7790617 PMCID: PMC7094930 DOI: 10.1007/bf01701485] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We report successful treatment of adult respiratory distress syndrome (ARDS) with artificial surfactant (40mg/kg, Colfosceril Palmitate, ‘Exosurf’, Wellcome) in an infant with severePneumocystis carinii pneumonitis.
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Affiliation(s)
- A J Slater
- Paediatric Intensive Care Unit, Hospitals for Sick Children, London, UK
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30
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Abstract
Pneumocystis carinii (PC) pneumonia is recognized as the leading cause of opportunistic pulmonary infections in immunocompromised hosts during the past decade. Although much remains unknown about pathogenesis and host response in PC, recent years, studies of PC have provided us with an increasing base of knowledge about this organism and its relationship to the host. These studies have led to a better understanding of mechanisms of PC attachment and injury to host cells. New information about the interaction of PC with pulmonary surfactant provides insight about the pathophysiology of PC pneumonia. The interplay of the organism, host inflammatory cells, release of cytokines, generation of toxic metabolites, and involvement of both cellular and humoral immunity is complex, but understanding the pathogenesis of PC pneumonia is necessary in order to develop new therapies for this disorder.
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Affiliation(s)
- T H Su
- Department of Internal Medicine, Indiana University School of Medicine, Indianapolis 46202
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31
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Lachmann B, Eijking EP, So KL, Gommers D. In vivo evaluation of the inhibitory capacity of human plasma on exogenous surfactant function. Intensive Care Med 1994; 20:6-11. [PMID: 8163763 DOI: 10.1007/bf02425047] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE The adult respiratory distress syndrome (ARDS) and neonatal respiratory distress syndrome (RDS) are characterized by high permeability pulmonary edema which contains plasma-derived proteins inhibiting pulmonary surfactant function. Currently, discussion continues as to what dose of surfactant is required for treatment of these syndromes. DESIGN The purpose of this study was to investigate the amount of exogenous surfactant needed to overcome the inhibitory components in human plasma. Male adult rats suffering from respiratory failure due to surfactant depletion after whole-lung lavage received human plasma (4 ml/kg body weight) mixed with surfactant at different concentrations, intratracheally. Rats receiving surfactant only at different concentrations served as controls. Blood gas analysis was performed. MEASUREMENTS AND RESULTS It was demonstrated that plasma (4 ml/kg-273 mg plasma proteins/kg) mixed with surfactant at 300 mg/kg was able to increase and maintain PaO2 at normal values. Plasma mixed with surfactant at 100 mg/kg, after initial restoration of blood gases, showed deterioration of PaO2 values. Plasma mixed with surfactant at a dose of 50 mg/kg did not improve PaO2 whereas surfactant at 50 mg/kg, without plasma, restored blood gases to pre-lavage values. CONCLUSION It is concluded that approximately 1 mg surfactant phospholipids is required to overcome the inhibitory effect of approximately 1 mg plasma proteins. For clinical practice this means that an excess of surfactant should be given, or repeatedly be substituted ("titrated") at low concentrations, until blood gases improve.
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Affiliation(s)
- B Lachmann
- Department of Anesthesiology, Erasmus University, Rotterdam, The Netherlands
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32
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Rice WR, Singleton FM, Linke MJ, Walzer PD. Regulation of surfactant phosphatidylcholine secretion from alveolar type II cells during Pneumocystis carinii pneumonia in the rat. J Clin Invest 1993; 92:2778-82. [PMID: 8254031 PMCID: PMC288477 DOI: 10.1172/jci116896] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We used an immunosuppressed rat model to test the hypothesis that normal mechanisms regulating surfactant phosphatidylcholine synthesis and secretion in alveolar type II cells are aberrant in Pneumocystis carinii pneumonia. Animal groups included: group 1, healthy controls; group 2, immunosuppressed, without pneumocystosis; group 3, immunosuppressed with pneumocystosis; group 4, immunosuppressed with well-established pneumocystosis treated with trimethoprim-sulfamethoxazole (TMP-SMX). Type II cells were isolated from rats in each group and compared for [3H]choline incorporation into phospholipid and response of the type II cells to secretagogues. Incorporation of [3H]choline into phospholipid subclasses exhibited significant differences. Incorporation into phosphatidylcholine fell from 89.3 +/- 2.2% of total incorporation in group 1 control rats to 79.6 +/- 3.1% in group 3 rats with P. carinii pneumonia, while incorporation into sphingomyelin rose from 5.6 +/- 1.2% in group 1 animals to 15.2 +/- 2.7% in group 3 rats. Incorporation of [3H]choline into phospholipid subclasses in cells from group 2 and group 4 animals was not different from incorporation for group 1 animals. Type II cells from group 1 and group 2 (immunosuppressed control) rats responded appropriately to the secretagogues ATP, TPA, and terbutaline with a marked increase in surfactant phosphatidylcholine secretion; the effect of ATP was also blocked by the lectin, concanavalin A. In contrast, type II cells from group 3 rats failed to respond to the secretagogues with a significant increase in phospholipid secretion. Although treatment of group 4 rats with TMP-SMX markedly reduced the P. carinii organism burden, type II cells from these animals also responded poorly to the secretagogues. The depressed type II cell function described here provides a mechanism for the observed decrease in surfactant phospholipids from bronchoalveolar lavage fluid of experimental animals and patients with P. carinii pneumonia. The data also suggest this defect may become irreversible with advanced disease.
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Affiliation(s)
- W R Rice
- Department of Pediatrics, Children's Hospital Medical Center, Cincinnati, Ohio 45229-2899
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