help button home button
AJRCMB
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Published ahead of print on April 17, 2008, doi:10.1165/rcmb.2007-0439OC
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
2007-0439OCv1
39/3/373    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Giebelen, I. A. J.
Right arrow Articles by van der Poll, T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Giebelen, I. A. J.
Right arrow Articles by van der Poll, T.
American Journal of Respiratory Cell and Molecular Biology. Vol. 39, pp. 373-379, 2008
© 2008 American Thoracic Society
DOI: 10.1165/rcmb.2007-0439OC

Endogenous β-Adrenergic Receptors Inhibit Lipopolysaccharide-Induced Pulmonary Cytokine Release and Coagulation

Ida A. J. Giebelen1,2, Masja Leendertse1,2, Mark C. Dessing1,2, Joost C. M. Meijers3, Marcel Levi3, Christian Draing4, Sonja von Aulock4 and Tom van der Poll1,2

1 Center for Infection and Immunity Amsterdam (CINIMA), 2 Center for Experimental and Molecular Medicine, 3 Department of Vascular Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; and 4 Department of Biochemical Pharmacology, University of Konstanz, Germany

Correspondence and requests for reprints should be addressed to Tom van der Poll, M.D., Academic Medical Center, Meibergdreef 9, Room G2-130, 1105 AZ Amsterdam, The Netherlands. E-mail: t.vanderpoll{at}amc.uva.nl


   Abstract
Top
 Abstract
CLINICAL RELEVANCE
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 References
 
β2-adrenergic receptors are expressed on different cell types in the lung, including respiratory epithelial cells, smooth muscle cells, and macrophages. The aim of the current study was to determine the role of β-adrenergic receptors in the regulation of lung inflammation induced by instillation via the airways of lipopolysaccharide (LPS) (a constituent of the gram-negative bacterial cell wall) or lipoteichoic acid (LTA) (a component of the gram-positive bacterial cell wall). Mice inhaled the β-adrenergic antagonist propranolol or saline 30 minutes before and 3 hours after intranasal LPS or LTA administration. LPS and LTA induced a profound inflammatory response in the lungs as reflected by an influx of neutrophils and the release of proinflammatory cytokines and chemokines into bronchoalveolar lavage fluid (BALF). Propranolol inhalation resulted in enhanced LPS-induced lung inflammation, which was reflected by a stronger secretion of TNF-{alpha}, IL-6, and monocyte chemoattractant protein-1 into BALF and by enhanced coagulation activation (thrombin–antithrombin complexes). In LTA-induced lung inflammation, propranolol did not influence cytokine release but potentiated activation of coagulation. Propranolol did not alter neutrophil recruitment in either model. This study suggests that β-adrenergic receptors, which are widely expressed in the lungs, serve as negative regulators of pulmonary cytokine release and coagulation induced by LPS and less so during LTA-induced pulmonary inflammation.

Key Words: lipopolysaccharide • lipoteichoic acid • lung inflammation • β-receptor antagonist • murine model • coagulation



   CLINICAL RELEVANCE
Top
 Abstract
 CLINICAL RELEVANCE
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 References
 
β-adrenergic receptors are widely expressed in the lung. We provide evidence that these receptors inhibit inflammation and coagulation in the bronchoalveolar space, thereby identifying a novel anti-inflammatory mechanism in the lung.

 
Functional β-adrenergic receptors are expressed on different cell types in the lung, including airway smooth muscle cells, respiratory epithelial cells, and macrophages (1–3). Stimulation of β2-adrenergic receptors on smooth muscle cells results in a bronchodilatory effect, and as a consequence β2-agonists are commonly used agents in the treatment of asthma and chronic obstructive pulmonary disease. In addition, β-adrenergic stimulation is associated with a variety of effects on immune cells, which are predominantly anti-inflammatory (4). Our laboratory recently showed that local administration of β2-agonists inhibits neutrophil recruitment and proinflammatory cytokine release in mice and humans challenged with LPS or Haemophilus influenzae via the airways (3, 5, 6). Additional evidence indicates that endogenous β-adrenergic agonists may also down-regulate lung inflammation and potentially protect against the development of acute lung injury (7, 8).

The most common cause of clinical acute lung injury is acute bacterial pneumonia, which is a leading cause of death due to infectious diseases (9, 10). Common respiratory pathogens include gram-negative and gram-positive bacterial species. LPS is a major component of the outer membrane of all gram-negative bacteria and the predominant inducer of inflammatory responses to these pathogens (11). Gram-positive bacteria do not contain LPS but express lipoteichoic acid (LTA) as an important proinflammatory constituent in their cell wall (12). LPS and LTA stimulate immune cells via different pattern recognition receptors: LPS induces signal transduction via Toll-like receptor (TLR)4, whereas LTA activates cells mainly via TLR2 (13, 14). Several laboratories, including our own, have investigated the effects of locally administered LPS or LTA to obtain more insight into the mechanisms involved in lung inflammation elicited by gram-negative and gram-positive pathogens, respectively; such models have also been used to study the pathogenesis of acute lung injury (15–20).

The primary objective of this study was to determine the role of endogenous β-adrenergic receptors in the regulation of the pulmonary response to LPS or LTA. We examined the effect of nebulized propranolol, a nonspecific β-receptor antagonist, in mice challenged with LPS or LTA via the airways. We studied not only lung inflammation, but also bronchoalveolar coagulation because there is a marked crosstalk between these systems and because an altered balance between coagulation and fibrinolysis has been implicated in the pathogenesis of pneumonia and lung injury (21). In addition, β-receptor stimulation has been reported to influence the hemostatic balance in vitro and in vivo (22–24).


   MATERIALS AND METHODS
Top
 Abstract
 CLINICAL RELEVANCE
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 References
 
Mice
Pathogen-free 7-week-old female C57BL/6 mice were purchased from Harlan (Horst, The Netherlands). The Institutional Animal Care and Use Committee of the Academic Medical Center approved all experiments. Mice were 8 weeks of age at the start of the experiments.

Design
At t = 0, mice were lightly anesthetized by inhalation of 2% isoflurane (Abbott Laboratories Ltd., Kent, UK)/2 liters of O2, after which they received 10 µg LPS (from Escherichia coli in 50 µl saline, serotype 055:B5) (Sigma, St. Louis, MO), 100 µg LTA (from Staphylococcus aureus, in 50 µl saline) (kind gift of Dr. T. Hartung, Univ. Konstanz, Germany [25]), or sterile saline (control, 50 µl). The LTA preparation was more than 99% pure, and the LPS contamination was less than 1 EU/mg as determined by the Limulus amoebocyte lysate assay (Charles River, Charleston, SC). Cellular effects of this LTA preparation and dose were TLR2 dependent, as determined by TLR2-deficient mouse cells, confirming that LPS contamination does not play a role in cell activation by the LTA preparation used (data not shown). Inhalation of nebulized propranolol (0 or 50 mg/ml in normal saline) (Sigma) or control solution (normal saline) was achieved 30 minutes before intranasal administration of saline, LPS, or LTA by attaching a plastic chamber (5 L) containing four (saline control experiments without LPS or LTA) or eight (experiments in which LPS or LTA was administered) conscious mice to an Aeroneb pro nebulizer (Medicare BV, Uitgeest, the Netherlands) as described (3, 5). Mice were killed 3 hours (LPS) or 6 hours (LPS, LTA) after the intranasal challenge; in experiments in which animals were followed for 6 hours, the inhalation of propranolol or saline was repeated at t = 3 hours. At the time of death, mice were anesthetized with Hypnorm (active ingredients: fentanyl citrate and fluanisone) (Janssen Pharmaceutica, Beerse, Belgium) and midazolam (Roche, Meidrecht, the Netherlands) and killed by bleeding out the vena cava inferior. Blood was collected in tubes containing EDTA.

Bronchoalveolar Lavage
Bronchoalveolar lavage (BAL) was performed as described (3, 5). The supernatant was collected and stored at –20°C until used for cytokine, chemokine, and protein measurements. The cell pellet was resuspended in saline, and total cell numbers were counted in each sample using a hemacytometer (Beckman Coulter, Fullerton, CA). Differential cell counts were performed on cytospin preparations stained with a modified Giemsa stain (Diff-Quick; Dade Behring AG, Düdingen, Switzerland).

Assays
(TNF-{alpha}, IL-6, and monocyte chemoattractant protein (MCP)-1 levels were determined using a commercially available cytometric beads array multiplex assay (BD Biosciences, San Jose, CA) in accordance with the manufacturer's recommendations. Macrophage inflammatory protein (MIP)-2 and cytokine-induced neutrophil chemoattractant (KC) levels were measured using commercially available enzyme-linked immunosorbent assay (ELISA) kits (R&D Systems, Abingdon, UK). Thrombin–antithrombin (TAT) complexes were measured by ELISA (Dade Behring, Marburg, Germany). Plasminogen activator inhibitor–1 antigen (PAI-1) was determined by ELISA, and plasminogen activator activity (PAA) was determined by an amidolytic assay as described (26, 27). Total protein was measured using Bradford Protein Assay (Bio-Rad, Hercules, CA).

Statistical Analysis
All values are mean ± SEM. Serial data were analyzed by Kruskal-Wallis test. Differences between groups were analyzed by Mann Whitney U test using GraphPad Prism version 4.00 (GraphPad Software; San Diego, CA). P < 0.05 was considered to be statistically significant.


   RESULTS
Top
 Abstract
 CLINICAL RELEVANCE
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 References
 
Propranolol Inhalation Dose-Dependently Enhances LPS-Induced TNF-{alpha}, IL-6, and MCP-1 Release
Several studies have shown that β2-adrenoceptor agonists, such as salmeterol and salbutamol, have anti-inflammatory properties in the lung (3, 5, 6). To determine the effect of inhibition of endogenous pulmonary β-adrenoceptors, mice were nebulized with propranolol and treated intranasally with LPS. In the absence of LPS challenge, propranolol inhalation did not result in cytokine release or in an alteration in the cellular composition of BAL fluid (BALF) (data not shown). Intranasal administration of saline was associated with very low or undetectable cytokine levels. Intranasal administration of LPS resulted in a profound rise in the concentrations of TNF-{alpha}, IL-6, and MCP-1 in BALF. Propranolol strongly and significantly enhanced LPS-induced secretion of TNF-{alpha}, IL-6, and MCP-1 into BALF, an effect that was apparent 3 hours after the LPS challenge (Figure 1).


Figure 1
View larger version (14K):
[in this window]
[in a new window]

  		Figure 1. Propranolol enhances lipopolysaccharide (LPS)-induced TNF-{alpha}, IL-6, and monocyte chemoattractant protein (MCP)-1 release. Mice inhaled propranolol or saline 30 minutes before and 3 hours after intranasal administration of LPS (10 µg). Bronchoalveolar lavage was performed 3 or 6 hours after LPS administration, and measurements were conducted in the fluid obtained. Data represent mean ± SEM of eight mice per group at each time point. * P < 0.05; *** P < 0.001 versus saline. Solid bars, saline; open bars, propranolol 10 mg/ml; hatched bars, propranolol 50 mg/ml.

 
Propranolol Does Not Affect LPS-Induced Neutrophil Recruitment
Recruitment of neutrophils to the pulmonary compartment is an important feature of pneumonia and acute lung injury. Intranasal instillation of LPS was associated with a brisk and strong influx of neutrophils into BALF (Table 1). Propranolol did not influence this characteristic inflammatory response. In addition, propranolol did not influence the number of macrophages or lymphocytes in BALF of mice challenged with LPS (Table 1). Propranolol did not modify the rise in the neutrophil attractive CXC chemokines KC and MIP-2 in BALF (Figure 2).


View this table:
[in this window]
[in a new window]

  		TABLE 1. EFFECT OF LIPOPOLYSACCHARIDE AND PROPRANOLOL ON THE CELLULAR COMPOSITION OF BRONCHOALVEOLAR LAVAGE FLUID

 

Figure 2
View larger version (14K):
[in this window]
[in a new window]

  		Figure 2. Propranolol does not influence LPS-induced cytokine-induced neutrophil chemoattractant (KC) or macrophage inflammatory protein (MIP)-2 release. Mice inhaled propranolol or saline 30 minutes before and 3 hours after intranasal administration of LPS (10 µg). Bronchoalveolar lavage was performed 3 or 6 hours after LPS administration, and measurements were conducted in the fluid obtained. Data represent mean ± SEM of eight mice per group at each time point. Solid bars, saline; open bars, propranolol 10 mg/ml; hatched bars, propranolol 50 mg/ml.

 
Propranolol Potentiates LPS-Induced Protein Leakage
LPS administration was associated with a significant rise in total protein levels in BALF (Figure 3). Propranolol 50 mg/ml, but not propranolol 10 mg/ml, enhanced this LPS-induced effect.


Figure 3
View larger version (12K):
[in this window]
[in a new window]

  		Figure 3. Propranolol enhances LPS-induced protein leakage. Mice inhaled propranolol or saline 30 minutes before and 3 hours after intranasal administration of LPS (10 µg). Bronchoalveolar lavage was performed 6 hours after LPS administration, and measurements were conducted in the fluid obtained. Data represent mean ± SEM of eight mice per group at each time point. *** P < 0.001 versus saline.

 
Propranolol Enhances Coagulation Activation in Mice Treated with LPS
To obtain insight into the role of endogenous β receptors in the regulation of the hemostatic balance in the lung exposed to LPS, we measured TATc, PAI-1, and PAA in BALF as indexes of coagulation and fibrinolysis (Figure 4). Although propranolol 10 mg/ml did not influence LPS-induced TATc release, propranolol 50 mg/ml profoundly enhanced the secretion of TATc into BALF, an effect that was present at 3 hours after LPS administration. Propranolol did not affect PAI-1 or PAA levels, indicating that fibrinolysis was not altered by this treatment.


Figure 4
View larger version (13K):
[in this window]
[in a new window]

  		Figure 4. Propranolol enhances LPS-induced coagulation activation. Mice inhaled propranolol or saline 30 minutes before and 3 hours after intranasal administration of LPS (10 µg). Bronchoalveolar lavage was performed 3 or 6 hours after LPS administration, and measurements were conducted in the fluid obtained. Data represent mean ± SEM of eight mice per group at each time point. * P < 0.05; ** P < 0.01 versus saline. Solid bars, saline; open bars, propranolol 10 mg/ml; hatched bars, propranolol 50 mg/ml.

 
Effect of Propranolol Inhalation on LTA-Induced Lung Inflammation and Coagulation
We wished to establish the role of endogenous β receptors in the regulation of lung inflammation and coagulation induced by LTA, a common proinflammatory component of the gram-positive cell wall. The effect of propranolol on LTA-induced responses in the mouse lung differed in several aspects from its effects on LPS-induced lung inflammation. Indeed, propranolol given at 50 mg/ml did not influence TNF-{alpha} or IL-6 levels (Figure 5), whereas it enhanced KC and MIP-2 release in BALF of mice challenged with intranasal LTA (Figure 6). LTA did not induce detectable MCP-1 release in BALF. Similar to its effects in the LPS model, propranolol did not affect neutrophil recruitment in response to intrapulmonary delivery of LTA (Table 2). Total protein concentrations were not altered by LTA or propranolol (data not shown). Finally, propranolol enhanced LTA-induced TATc release but did not influence PAI-1 or PAA levels, thereby mimicking its effects on LPS-induced coagulation and fibrinolysis (Figure 7).


Figure 5
View larger version (11K):
[in this window]
[in a new window]

  		Figure 5. Propranolol does not influence lipoteichoic acid (LTA)–induced cytokine release. Mice inhaled propranolol or saline 30 minutes before and 3 hours after intranasal administration of LTA (100 µg). Bronchoalveolar lavage was performed 6 hours after LTA administration, and measurements were conducted in the fluid obtained. Data represent mean ± SEM of eight mice per group.

 

Figure 6
View larger version (11K):
[in this window]
[in a new window]

  		Figure 6. Propranolol enhances LTA-induced cytokine-induced neutrophil KC and MIP-2 release. Mice inhaled propranolol or saline 30 minutes before and 3 hours after intranasal administration of LTA (100 µg). Bronchoalveolar lavage was performed 6 hours after LTA administration, and measurements were conducted in the fluid obtained. Data represent mean ± SEM of eight mice per group. * P < 0.05; *** P < 0.001 versus saline.

 

View this table:
[in this window]
[in a new window]

  		TABLE 2. EFFECT OF LIPOTEICHOIC ACID AND PROPRANOLOL ON CELLULAR COMPOSITION OF BRONCHOALVEOLAR LAVAGE FLUID AFTER 6 h

 

Figure 7
View larger version (9K):
[in this window]
[in a new window]

  		Figure 7. Propranolol enhances LTA-induced coagulation activation. Mice inhaled propranolol or saline 30 minutes before and 3 hours after intranasal administration of LTA (100 µg). Bronchoalveolar lavage was performed 6 hours after LTA administration, and measurements were conducted in the fluid obtained. Data represent mean ± SEM of eight mice per group. * P < 0.05 versus saline.

 

   DISCUSSION
Top
 Abstract
 CLINICAL RELEVANCE
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
References
 
Acute bacterial pneumonia is the most common cause of acute lung injury. In the current study, we investigated the role of endogenous β-adrenergic receptors in bronchoalveolar inflammation induced by intrapulmonary delivery of LPS, an important constituent of the gram-negative cell wall and an established TLR4 ligand, or LTA, a proinflammatory component of the gram-positive cell wall and an established TLR2 ligand. We demonstrate that inhalation of the β-adrenergic antagonist propranolol differentially affects LPS- and LTA-induced lung inflammation. In particular, although propranolol enhanced LPS-induced release of TNF-{alpha}, IL-6, and MCP-1 into BALF, it did not alter these responses upon LTA administration. Moreover, propranolol potentiated local activation of coagulation upon LPS and LTA instillation while not influencing fibrinolysis. Propranolol did not influence neutrophil recruitment in either model. Together, these data suggest that endogenous β-adrenergic receptors are involved in the regulation of lung inflammation induced by two distinct and common bacterial TLR ligands.

Our finding that propranolol administered via the airways increased local TNF-{alpha} release after LPS instillation is in line with several earlier studies. Administration of propranolol to mice challenged with LPS intraperitoneally enhanced circulating TNF-{alpha} concentrations (28–30). In a model of hemorrhage-induced lung injury, intraperitoneal administration of propranolol further increased (relative to the effect of hemorrhage alone) TNF-{alpha} and IL-1β expression in pulmonary mononuclear cells (7). However, systemic propranolol treatment did not influence the expression of TNF-{alpha} mRNA by lung neutrophils after intraperitoneal LPS injection (31). The design of this investigation (31) differed from our current study, in which propranolol and LPS were administered via the airways. Our laboratory recently showed that local stimulation of β-adrenergic receptors in the bronchoalveolar space using specific β2-agonists attenuated the LPS-induced production of TNF-{alpha} in mice and humans (5, 6). Moreover, salbutamol and salmeterol diminished TNF-{alpha} levels in the lungs of mice with respiratory tract infection caused by the gram-negative pathogen H. influenzae (3). Earlier studies reported on the systemic effects of β-adrenergic agonists on TNF-{alpha} release into the circulation after systemic (intravenous or intraperitoneal) administration of LPS (28, 32, 33). To the best of our knowledge, the effect of β-adrenergic stimulation or blockade on LTA-induced TNF-{alpha} production has not been studied before. Our finding that propranolol did not alter this response suggests that pulmonary TNF-{alpha} release in response to LTA is mediated by mechanisms or cell types that are different from those after LPS administration. Our laboratory recently showed that incubation of mouse alveolar macrophages (MH-S cells) with H. influenzae in the presence of propranolol was associated with enhanced TNF-{alpha} release relative to that detected after incubation with H. influenzae alone (3). In this respect it is of note that alveolar macrophages express catecholamine-generating and catecholamine-degrading enzymes and release epinephrine and norepinephrine after exposure to LPS in vitro (34). The mechanism by which β-adrenergic stimulation influences proinflammatory cytokine production by macrophages has been linked to a stimulating effect on adenylyl cyclase, leading to an increase in intracellular 3'-5'-cyclic adenosine monophosphate levels (cAMP) (2, 32, 35). Possibly, TNF-{alpha} released into the bronchoalveolar space in response to intrapulmonary delivery of LPS or LTA is derived from different cell sources, whereby LTA-induced TNF-{alpha} production is less responsive to β receptor stimulation and the ensuing increase in cAMP levels.

β-adrenergic blockade did not influence the recruitment of neutrophils into the bronchoalveolar space after instillation of LPS or LTA. These results are in line with several earlier studies. Abraham and colleagues (31) reported that systemic propranolol treatment did not influence the recruitment of neutrophils to the lung after intraperitoneal LPS injection. In addition, in a model of hemorrhage-induced lung injury, intraperitoneal administration of propranolol did not affect neutrophil accumulation or activation (7, 36). The effects of β-adrenergic agonists on neutrophil trafficking likely vary depending on the inciting stimulus: Salmeterol reduced the influx of neutrophils into the lungs after LPS administration via the airways (5, 6), but it did not affect neutrophil recruitment during H. influenzae pneumonia (3). Moreover, salmeterol did not alter neutrophil accumulation in lungs of rats with acid aspiration–induced lung injury (35). Systemic administration of several β2-agonists has been reported to diminish neutrophil recruitment to the lungs of experimental animals (33, 37, 38). Propranolol increased the concentrations of the CXC chemokines KC and MIP-2 in BALF of mice upon exposure of LTA, whereas such an effect was not observed after intrapulmonary delivery of LPS. In the presence of higher local levels of these neutrophil-attracting chemokines in LTA-challenged lungs, one might have expected enhanced neutrophil recruitment to the bronchoalveolar space. The fact that this did not occur may suggest that propranolol inhalation results in a relatively reduced neutrophil influx after LTA administration. More research is warranted to address this issue.

Although the primary objective of our study was to determine the role of endogenous β receptors on lung inflammation, we measured total protein concentrations in BALF as one parameter of protein leakage into the bronchoalveolar space (39). LPS administration was associated with a rise in BALF total protein concentrations, which was exaggerated by propranolol. In line with these results, in a study focusing on the lung fluid balance and pulmonary vascular permeability, Su and colleagues demonstrated that propranolol given intraperitoneally and intratracheally enhanced the accumulation of extravascular lung water during acute E. coli pneumonia by increasing vascular injury and impairing the resolution of alveolar edema (8). Conversely, β-adrenergic agonists reduced pulmonary edema and vascular permeability while increasing alveolar fluid clearance during acid aspiration–induced lung injury (35).

Local activation of the coagulation system within the pulmonary compartment has been implicated in the pathogenesis of bacterial pneumonia and acute lung injury (21, 40). We therefore examined the effect of β-adrenergic blockade on the activation of coagulation induced by intranasal administration of LPS or LTA. Our laboratory earlier reported an increase in BALF TATc concentrations after instillation of LPS via the airways of mice and humans (16, 24). We now expand these data, showing that S. aureus LTA elicits the same response. Propranolol enhanced the procoagulant response to LPS and LTA. It has been suggested that β-adrenergic agents can inhibit the expression of tissue factor, which is considered the main initiator of coagulation activation, by increasing intracellular cAMP levels (22). In line with these results, intravenous infusion of epinephrine attenuated systemic coagulation activation upon intravenous injection of LPS in healthy humans (23). However, salmeterol did not alter the procoagulant response in the lungs of healthy subjects after inhalation of nebulized LPS, although this lack of an effect may have been caused by insufficient dosing (24). PAI-1 is the main inhibitor of fibrinolysis in the lung of which the release strongly increases during lung infection and/or injury (21, 40). Propranolol did not affect PAI-1 release or PAA. In healthy humans, inhalation of a β2-agonist did not influence LPS-induced PAI-1 release in BALF (24).

Shortly after the completion of our studies, Flierl and colleagues reported on the role of endogenous adrenergic receptors in LPS and immune complex–induced lung injury in rats, focusing primarily on albumin leak into BALF (34). Intraperitoneal administration of β-adrenergic antagonists did not significantly influence vascular leakage of albumin into lungs in either model. In contrast, blockade of {alpha}2-adrenergic receptors reduced the intensity of the albumin leak into lung in the two models of injury. The effect of adrenergic blockers on cytokine release or activation of coagulation in the lung compartment was not reported, thereby hampering a direct comparison with our current investigation. Although Flierl and colleagues (34) administered adrenergic blockers intraperitoneally, we chose direct intrapulmonary delivery.

Our study is limited by the fact that the role of {alpha}-adrenergic receptors in LPS- or LTA-induced lung inflammation was not investigated. Earlier studies done by Abraham and colleagues have documented a role for {alpha} receptors in the regulation of lung inflammation induced by systemic challenges (7, 31, 36). In particular, {alpha} receptor blockade by intraperitoneal administration of phentolamine inhibited TNF-{alpha} and IL-1β mRNA expression in pulmonary mononuclear cells harvested from lung parenchyma 1 hour after hemorrhage (7), whereas the same intervention enhanced TNF-{alpha} and IL-1β mRNA expression in pulmonary neutrophils 1 hour after intraperitoneal administration of LPS (31). Systemic {alpha} receptor blockade by phentolamine attenuated the increase in pulmonary myeloperoxidase levels (reflecting the accumulation of neutrophils) after hemorrhage, whereas it enhanced this response after intraperitoneal LPS injection (36). These studies differ in several aspects from our current study: The challenges to induce lung inflammation were systemic in nature, whereas we administered LPS or LTA directly into the airways, and the adrenergic receptor blocking agents were given intraperitoneally, whereas we sought to block β-adrenergic receptors in the lungs. Nonetheless, these studies indicate that pulmonary {alpha}-adrenergic receptors may play a role in the regulation of lung inflammation as studied in the current manuscript. Therefore, studies in which {alpha} receptor blockers are administered via the airways are warranted.

In conclusion, this study demonstrated that β-adrenergic blockade, achieved by inhalation of nebulized propranolol, differentially affects LPS- and LTA-induced lung inflammation, whereby in particular the effects of LPS were exaggerated. These data suggest that LPS elicits an increase in the endogenous β-adrenergic receptor tone in the airways, which may serve to protect the lung against excessive cytokine release and coagulation.


   Acknowledgments
 
The authors thank Joost Daalhuisen and Marieke ten Brink for excellent technical assistance.


   Footnotes
 
Originally Published in Press as DOI: 10.1165/rcmb.2007-0439OC on April 17, 2008

Conflict of Interest Statement: None of the authors has a financial relationship with a commercial entity that has an interest in the subject of this manuscript.

Received in original form December 4, 2007

Accepted in final form March 5, 2008


   References
Top
 Abstract
 CLINICAL RELEVANCE
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 References
 

  1. Svedmyr N. The current place of beta 2-agonists in the management of asthma. Lung 1990;168:105–110.[CrossRef][Medline]
  2. Barnes PJ. Effect of beta-agonists on inflammatory cells. J Allergy Clin Immunol 1999;104:10–17.[CrossRef]
  3. Maris NA, Florquin S, van't Veer C, de Vos AF, Buurman W, Jansen HM, van der Poll T. Inhalation of beta 2 agonists impairs the clearance of nontypable Haemophilus influenzae from the murine respiratory tract. Respir Res 2006;7:57.[CrossRef][Medline]
  4. Johnson M, Rennard S. Alternative mechanisms for long-acting beta(2)-adrenergic agonists in COPD. Chest 2001;120:258–270.[CrossRef][Medline]
  5. Maris NA, van der Sluijs KF, Florquin S, de Vos AF, Pater JM, Jansen HM, van der Poll T. Salmeterol, a beta2-receptor agonist, attenuates lipopolysaccharide-induced lung inflammation in mice. Am J Physiol Lung Cell Mol Physiol 2004;286:1122–1128.[CrossRef]
  6. Maris NA, de Vos AF, Dessing MC, Spek CA, Lutter R, Jansen HM, van der Zee JS, Bresser P, van der Poll T. Antiinflammatory effects of salmeterol after inhalation of lipopolysaccharide by healthy volunteers. Am J Respir Crit Care Med 2005;172:878–884.[Abstract/Free Full Text]
  7. Le Tulzo Y, Shenkar R, Kaneko D, Moine P, Fantuzzi G, Dinarello CA, Abraham E. Hemorrhage increases cytokine expression in lung mononuclear cells in mice: involvement of catecholamines in nuclear factor-kappab regulation and cytokine expression. J Clin Invest 1997;99:1516–1524.[Medline]
  8. Su X, Robriquet L, Folkesson HG, Matthay MA. Protective effect of endogenous beta-adrenergic tone on lung fluid balance in acute bacterial pneumonia in mice. Am J Physiol Lung Cell Mol Physiol 2006;290:L769–L776.[Abstract/Free Full Text]
  9. Eisner MD, Thompson T, Hudson LD, Luce JM, Hayden D, Schoenfeld D, Matthay MA. Efficacy of low tidal volume ventilation in patients with different clinical risk factors for acute lung injury and the acute respiratory distress syndrome. Am J Respir Crit Care Med 2001;164:231–236.[Abstract/Free Full Text]
  10. Bartlett JG, Dowell SF, Mandell LA, File TM Jr, Musher DM, Fine MJ. Practice guidelines for the management of community-acquired pneumonia in adults. Infectious Diseases Society of America. Clin Infect Dis 2000;31:347–382.[CrossRef][Medline]
  11. Beutler B, Rietschel ET. Innate immune sensing and its roots: the story of endotoxin. Nat Rev Immunol 2003;3:169–176.[CrossRef][Medline]
  12. Ginsburg I. Role of lipoteichoic acid in infection and inflammation. Lancet Infect Dis 2002;2:171–179.[CrossRef][Medline]
  13. Akira S, Uematsu S, Takeuchi O. Pathogen recognition and innate immunity. Cell 2006;124:783–801.[CrossRef][Medline]
  14. Beutler B, Jiang Z, Georgel P, Crozat K, Croker B, Rutschmann S, Du X, Hoebe K. Genetic analysis of host resistance: toll-like receptor signaling and immunity at large. Annu Rev Immunol 2006;24:353–389.[CrossRef][Medline]
  15. Leemans JC, Vervoordeldonk MJ, Florquin S, van Kessel KP, van der Poll T. Differential role of interleukin-6 in lung inflammation induced by lipoteichoic acid and peptidoglycan from Staphylococcus aureus. Am J Respir Crit Care Med 2002;165:1445–1450.[Abstract/Free Full Text]
  16. Rijneveld AW, Weijer S, Florquin S, Esmon CT, Meijers JC, Speelman P, Reitsma PH, ten Cate H, van der Poll T. Thrombomodulin mutant mice with a strongly reduced capacity to generate activated protein C have an unaltered pulmonary immune response to respiratory pathogens and lipopolysaccharide. Blood 2004;103:1702–1709.[Abstract/Free Full Text]
  17. Knapp S, Florquin S, Golenbock DT, van der Poll T. Pulmonary lipopolysaccharide (LPS)-binding protein inhibits the LPS-induced lung inflammation in vivo. J Immunol 2006;176:3189–3195.[Abstract/Free Full Text]
  18. von Aulock S, Morath S, Hareng L, Knapp S, van Kessel KP, van Strijp JA, Hartung T. Lipoteichoic acid from Staphylococcus aureus is a potent stimulus for neutrophil recruitment. Immunobiology 2003;208:413–422.[CrossRef][Medline]
  19. Ueno H, Matsuda T, Hashimoto S, Amaya F, Kitamura Y, Tanaka M, Kobayashi A, Maruyama I, Yamada S, Hasegawa N, et al. Contributions of high mobility group box protein in experimental and clinical acute lung injury. Am J Respir Crit Care Med 2004;170:1310–1316.[Abstract/Free Full Text]
  20. Speyer CL, Neff TA, Warner RL, Guo RF, Sarma JV, Riedemann NC, Murphy ME, Murphy HS, Ward PA. Regulatory effects of iNOS on acute lung inflammatory responses in mice. Am J Pathol 2003;163:2319–2328.[Abstract/Free Full Text]
  21. Levi M, Schultz MJ, Rijneveld AW, van der Poll T. Bronchoalveolar coagulation and fibrinolysis in endotoxemia and pneumonia. Crit Care Med 2003;31:238–242.[CrossRef]
  22. Ollivier V, Houssaye S, Ternisien C, Leon A, de Verneuil H, Elbim C, Mackman N, Edgington TS, de Prost D. Endotoxin-induced tissue factor messenger RNA in human monocytes is negatively regulated by a cyclic AMP-dependent mechanism. Blood 1993;81:973–979.[Abstract/Free Full Text]
  23. van der Poll T, Levi M, Dentener M, Jansen PM, Coyle SM, Braxton CC, Buurman WA, Hack CE, ten Cate JW, Lowry SF. Epinephrine exerts anticoagulant effects during human endotoxemia. J Exp Med 1997;185:1143–1148.[Abstract/Free Full Text]
  24. Maris NA, de Vos AF, Bresser P, van der Zee JS, Jansen HM, Levi M, van der Poll T. Salmeterol enhances pulmonary fibrinolysis in healthy volunteers. Crit Care Med 2007;35:57–63.[CrossRef][Medline]
  25. Morath S, Geyer A, Hartung T. Structure-function relationship of cytokine induction by lipoteichoic acid from Staphylococcus aureus. J Exp Med 2001;193:393–397.[Abstract/Free Full Text]
  26. Verheijen JH, Chang GT, Kluft C. Evidence for the occurrence of a fast-acting inhibitor for tissue-type plasminogen activator in human plasma. Thromb Haemost 1984;51:392–395.[Medline]
  27. Verheijen JH, Mullaart E, Chang GT, Kluft C, Wijngaards GA. Simple, sensitive spectrophotometric assay for extrinsic (tissue-type) plasminogen activator applicable to measurements in plasma. Thromb Haemost 1982;48:266–269.[Medline]
  28. Sekut L, Champion BR, Page K, Menius JA Jr, Connolly KM. Anti-inflammatory activity of salmeterol: down-regulation of cytokine production. Clin Exp Immunol 1995;99:461–466.[Medline]
  29. Elenkov IJ, Hasko G, Kovacs KJ, Vizi ES. Modulation of lipopolysaccharide-induced tumor necrosis factor-alpha production by selective alpha- and beta-adrenergic drugs in mice. J Neuroimmunol 1995;61:123–131.[CrossRef][Medline]
  30. Pettipher ER, Labasi JM, Salter ED, Stam EJ, Cheng JB, Griffiths RJ. Regulation of tumour necrosis factor production by adrenal hormones in vivo: insights into the antiinflammatory activity of rolipram. Br J Pharmacol 1996;117:1530–1534.[Medline]
  31. Abraham E, Kaneko DJ, Shenkar R. Effects of endogenous and exogenous catecholamines on LPS-induced neutrophil trafficking and activation. Am J Physiol 1999;276:1–8.
  32. van der Poll T, Coyle SM, Barbosa K, Braxton CC, Lowry SF. Epinephrine inhibits tumor necrosis factor-alpha and potentiates interleukin 10 production during human endotoxemia. J Clin Invest 1996;97:713–719.[Medline]
  33. Wu CC, Liao MH, Chen SJ, Chou TC, Chen A, Yen MH. Terbutaline prevents circulatory failure and mitigates mortality in rodents with endotoxemia. Shock 2000;14:60–67.[Medline]
  34. Flierl MA, Rittirsch D, Nadeau BA, Chen AJ, Sarma JV, Zetoune FS, McGuire SR, List RP, Day DE, Hoesel LM, et al. Phagocyte-derived catecholamines enhance acute inflammatory injury. Nature 2007;449:721–725.[CrossRef][Medline]
  35. Arcaroli J, Yang KY, Yum HK, Kupfner J, Pitts TM, Park JS, Strassheim D, Abraham E. Effects of catecholamines on kinase activation in lung neutrophils after hemorrhage or endotoxemia. J Leukoc Biol 2002;72:571–579.[Abstract/Free Full Text]
  36. McAuley DF, Frank JA, Fang X, Matthay MA. Clinically relevant concentrations of beta2-adrenergic agonists stimulate maximal cyclic adenosine monophosphate-dependent airspace fluid clearance and decrease pulmonary edema in experimental acid-induced lung injury. Crit Care Med 2004;32:1470–1476.[CrossRef][Medline]
  37. Whelan CJ, Johnson M, Vardey CJ. Comparison of the anti-inflammatory properties of formoterol, salbutamol and salmeterol in guinea-pig skin and lung. Br J Pharmacol 1993;110:613–618.[Medline]
  38. Saleh TS, Calixto JB, Medeiros YS. Anti-inflammatory effects of theophylline, cromolyn and salbutamol in a murine model of pleurisy. Br J Pharmacol 1996;118:811–819.[Medline]
  39. van Westerloo DJ, Giebelen IA, Florquin S, Daalhuisen J, Bruno MJ, de Vos AF, Tracey KJ, van der Poll T. The cholinergic anti-inflammatory pathway regulates the host response during septic peritonitis. J Infect Dis 2005;191:2138–2148.[CrossRef][Medline]
  40. Abraham E. Coagulation abnormalities in acute lung injury and sepsis. Am J Respir Cell Mol Biol 2000;22:401–404.[Free Full Text]




This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
2007-0439OCv1
39/3/373    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Giebelen, I. A. J.
Right arrow Articles by van der Poll, T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Giebelen, I. A. J.
Right arrow Articles by van der Poll, T.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Proc. Am. Thorac. Soc. Am. J. Respir. Crit. Care Med.
Copyright © 2008 American Thoracic Society.