AJP - Lung AJP: Renal Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Lung Cell Mol Physiol 293: L60-L68, 2007. First published April 13, 2007; doi:10.1152/ajplung.00284.2006
1040-0605/07 $8.00
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
293/1/L60    most recent
00284.2006v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Web of Science (8)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Wilson, M. R.
Right arrow Articles by Takata, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Wilson, M. R.
Right arrow Articles by Takata, M.

TRANSLATIONAL PHYSIOLOGY

Differential roles of p55 and p75 tumor necrosis factor receptors on stretch-induced pulmonary edema in mice

Michael R. Wilson, Michael E. Goddard, Kieran P. O'Dea, Sharmila Choudhury, and Masao Takata

Department of Anaesthetics, Pain Medicine, and Intensive Care, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, United Kingdom

Submitted 28 July 2006 ; accepted in final form 12 April 2007


   ABSTRACT
TOP
 ABSTRACT
METHODS
 RESULTS
 DISCUSSION
 GRANTS
 REFERENCES
 
Ventilator-induced lung injury plays a crucial role in the outcome of patients with acute lung injury. Previous studies have shown a role for the cytokine tumor necrosis factor-{alpha} (TNF) in stretch-induced alveolar neutrophil recruitment, but the involvement of TNF in stretch-induced pulmonary edema is unclear. We investigated the effects of TNF through its individual p55 and p75 receptors on early pulmonary edema formation during high stretch ventilation, before neutrophil infiltration. Anesthetized wild-type or TNF receptor single/double knockout mice were ventilated with high tidal volume (~38 ml/kg) for 2 h or until they developed arterial hypotension. Pulmonary edema was assessed by physiological parameters including respiratory mechanics and blood gases, and by lavage fluid protein, lung wet:dry weight ratio, and lung permeability measurements using fluorescence-labeled albumin. High stretch ventilation in wild-type and TNF receptor double knockout animals induced similar pulmonary edema, and only 25–30% of mice completed the protocol. In contrast, the p55 receptor knockout mice were strongly protected from edema formation, with all animals completing the protocol. Myeloperoxidase assay indicated that this protective effect was not associated with decreased pulmonary neutrophil sequestration. The p75 receptor knockout mice, however, displayed increased susceptibility to edema formation, and no animals survived the full 2 h. These results demonstrate a novel role for TNF signaling (independent from its effects on neutrophil recruitment) specifically through the p55 receptor, in promoting high stretch-induced pulmonary edema, whereas p75 signaling may play an opposing role.

acute lung injury; cytokines; inflammation; ventilator-induced lung injury

ACUTE LUNG INJURY (ALI) and acute respiratory distress syndrome (ARDS) are major causes of mortality in critical care patients (72). Although mechanical ventilation is an essential treatment for ALI/ARDS, this can itself exacerbate or induce lung injury, known as ventilator-induced lung injury (VILI) (1, 11, 53). Despite the introduction of "lung protective" ventilation, it is not possible by merely adjusting ventilator settings to completely eliminate the iatrogenic consequences of VILI (46, 64). A better understanding of the pathophysiology of VILI is essential to identify novel targets for intervention.

The proinflammatory cytokine tumor necrosis factor-{alpha} (TNF) has been implicated in the pathogenesis of both experimental and clinical ALI (5, 35, 36, 39, 42, 55), yet until recently, its involvement in VILI, in particular, lung injury induced by pure mechanical stretch, has been controversial (7, 10, 17, 24, 25, 48–50, 57, 60, 61, 63, 69). Using in vivo mouse models, we have shown that high stretch ventilation in the absence of underlying injury induced transient intrapulmonary expression of bioactive TNF in the early stage of VILI (74) and that alveolar neutrophil infiltration in later stages of VILI was reduced either by intratracheal administration of anti-TNF antibody or in mice lacking both the p55 (type I) and p75 (type II) TNF receptors (75). These studies demonstrated that stretch-induced pulmonary inflammation, as evaluated by alveolar neutrophil recruitment, is significantly mediated by TNF signaling during VILI. Interestingly, we observed that pulmonary edema induced by high mechanical stretch, which occurred rapidly before neutrophil infiltration, was not attenuated in the TNF receptor double knockout mice (75), a finding independently reported by Yoshikawa and colleagues (78). Thus it has been generally considered that TNF is not involved in the development of early, neutrophil-independent, stretch-induced pulmonary edema (10, 78), despite the fact that TNF is already expressed within the same time frame during the course of VILI (28, 51, 74).

Although there is strong evidence that TNF is able to influence the progression of pulmonary edema by altering epithelial/endothelial cell functions, the predicted net effects of TNF on pulmonary edema formation is conflicting in the literature. For example, TNF may either promote pulmonary edema by increasing epithelial/endothelial permeability (30, 38, 44, 45) or oppose edema by enhancing alveolar fluid reabsorption (3, 13, 19). Such apparently conflicting effects of TNF may be related to the poorly understood processes of differential p55 and p75 receptor signaling. It is increasingly clear that the two TNF receptors can signal through different intracellular pathways and may induce different cellular responses (27, 33, 43, 71). In fact, recent reports have raised the possibility that the two TNF receptors may in some circumstances signal in a directly opposing manner, e.g., in models of retinal ischemic injury (18) and sepsis induced by cecal ligation and puncture (12).

We therefore hypothesized that differential signaling through the individual TNF receptors may have opposing effects on pulmonary edema development induced by high stretch ventilation, which could be masked by the absence of both receptors in TNF receptor double knockout mice. To address this, we investigated the development of pulmonary edema in mice lacking one or both of the TNF receptors and demonstrated for the first time that p55 signaling promotes edema development induced by high stretch ventilation, while this is seemingly opposed by signaling through the p75 receptor.


   METHODS
TOP
 ABSTRACT
 METHODS
RESULTS
 DISCUSSION
 GRANTS
 REFERENCES
 
Animal preparation. All protocols were approved by the United Kingdom Home Office in accordance with the Animals (Scientific Procedures) Act 1986, United Kingdom. We used wild-type (WT) male C57BL6 mice (Charles River) aged 10–18 wk, age-matched male p55–/– TNF receptor knockout (p55KO), p75–/– TNF receptor knockout (p75KO), or p55–/–p75–/– TNF receptor double knockout (DKO) mice (generous gifts from Amgen, Thousand Oaks, CA) (43). The DKO mice were generated by crossing the p55KO and p75KO strains. The p55KO mice were C57BL6 inbred, whereas the p75KO and DKO mice were backcrossed onto their WT C57BL6 strain for five generations. Mice were anesthetized by intraperitoneal injection of 2.5 ml/kg Hypnorm (0.8 mg/kg Fentanyl, 25 mg/kg Fluanisone) and 2.5 ml/kg Midazolam (12.5 mg/kg). The surgical preparation has been described in detail previously (6, 20, 74, 75). Briefly, mice were ventilated via endotracheal tube using a custom-made mouse ventilator-pulmonary function testing system with O2 (supplemented with 5% CO2 during high stretch to prevent hypocapnia). The left carotid artery was cannulated for monitoring arterial blood pressure (BP) and blood gases and for saline infusion (0.4 ml/h). During instrumentation, animals were ventilated with low stretch, i.e., tidal volume (VT) of 6–7 ml/kg, 2.5 cmH2O positive end-expiratory pressure (PEEP), and respiratory rate (RR) of 120 breaths/min.

Physiological measurements during high stretch ventilation. Following physiological measurements to ensure stability of the preparation, mice were ventilated with high stretch, i.e., initial peak inspiratory pressure (PIP) set at 45–46 cmH2O (mean VT 38.5 ± 3.8 ml/kg; means ± SD), 0 PEEP, RR of 90/min. Immediately after the start of high stretch ventilation, a 200-µl saline bolus was given to aid with venous return. High stretch ventilation with the same constant VT was continued either for 2 h or until imminent cardiorespiratory collapse was indicated by BP <45 mmHg (74), whichever occurred first. Airway pressure, gas flow, and mean BP were monitored continually throughout the experiments via transducers. Respiratory system resistance (Rrs) and compliance (Crs) were determined by the end-inflation occlusion technique (15) throughout the ventilatory protocol. Blood gas analyses (~70 µl/sample, with bolus administration of saline to replace fluids) were carried out immediately after surgery, after 60 min of high stretch ventilation, and at the end of the protocol.

At the conclusion of ventilatory protocols, mice were euthanized by anesthetic overdose, and some animals were subjected to lung lavage as described previously (74). In these animals, protein concentration in lavage fluid was determined by the Bradford method (2) using a protein assay kit (Bio-Rad Laboratories, Hemel Hempstead, UK), and levels of TNF receptors (p55 and p75), macrophage inflammatory protein-2 (MIP-2), and keratinocyte-derived chemokine (KC) protein were measured using sandwich ELISA kits (R&D Systems, Abingdon, UK). Cells in lavage fluid were counted by hemocytometer, and differential cytology was performed on Diff-Quik-stained samples prepared by cytospin (Shandon, Runcorn, UK). In nonlavaged animals, the right lung was removed, weighed, and dried at 60°C for wet:dry ratio determination. In some lavaged WT and p55KO animals, the lungs were removed, and MPO activity was quantified as described previously (6, 52). In brief, lung tissue was homogenized, sonicated two times, freeze-thawed three times, and centrifuged. The supernatant was mixed with O-dianisidine (Sigma-Aldrich, Poole, UK) and hydrogen peroxide, and changes in absorbance were measured over 3 min with the results expressed as optical density per minute.

Permeability measurements during high stretch ventilation. In a separate series of experiments, pulmonary endothelial/epithelial permeability to a fluorescence-labeled albumin was assessed in each strain of mice during high stretch ventilation, using an adaptation of a previously described protocol (73). Alexa Fluor 594-conjugated albumin (Invitrogen) was infused into the right jugular vein of anesthetized instrumented mice, which were then ventilated with high stretch for 60 min. Animals were killed, lungs were lavaged, and blood was collected by cardiac puncture. Lung permeability was estimated by the ratio of lavage fluid:plasma fluorescent signal.

Data analysis. Data are expressed as means ± SD. Statistical analyses were carried out by t-tests, ANOVA with Bonferroni tests, general linear mixed model analysis, and Kaplan-Meier survival analysis with log-rank tests, using SPSS version 14.0 (Chicago, IL). A P value of less than 0.05 was considered significant.


   RESULTS
TOP
 ABSTRACT
 METHODS
 RESULTS
DISCUSSION
 GRANTS
 REFERENCES
 
Physiological parameters. In WT animals, high stretch ventilation produced progressive increases in PIP during the 2-h ventilation protocol (Fig. 1). PIP was stable for 80–90 min but thereafter increased rapidly, whereas BP was well maintained throughout the protocol until the last 5–10 min of the experiment (when lung injury indicated by PIP became severe), consistent with our previous studies using similar mouse VILI models (6, 74, 75). We found that the patterns of PIP changes in response to high stretch were very different among the WT and TNF receptor knockout animals (P < 0.001, Fig. 2A). TNF receptor DKO mice showed similar PIP changes to WT animals with comparable kinetics. However, p55KO mice did not show any increases in PIP across the entire 2-h ventilation protocol. In contrast, p75KO mice displayed more rapid increases in PIP, suggesting a greater susceptibility of these mice to high stretch-induced injury. The PIP values at the end of the protocol (Fig. 2B) were similar in WT and DKO mice, but higher (P < 0.05) in p75KO mice and lower (P < 0.05) in p55KO mice, compared with both WT and DKO animals.


Figure 1
View larger version (12K):
[in this window]
[in a new window]

  		Fig. 1. High stretch-induced changes in peak inspiratory pressure (PIP) and blood pressure (BP) in wild-type mice. Mice were ventilated with high stretch ventilation at a constant tidal volume (VT; initial PIP 45–46 cmH2O which corresponds to a VT of 38.5 ± 3.8 ml/kg) for up to 2 h. PIP remained stable until 80–90 min and thereafter increased dramatically. BP showed a transient decline on initiation of high stretch ventilation, but thereafter was stable until a rapid decline that occurred within 5–10 min at the end of the experiment. N = 11 at the start of ventilation. Data points represent the mean of all surviving animals at each time point.

 

Figure 2
View larger version (22K):
[in this window]
[in a new window]

  		Fig. 2. PIP changes induced by high stretch ventilation in wild-type (WT) and TNF receptor knockout mice. A: high stretch ventilation induced a gradual increase over time in WT mice. p55–/–p75–/– TNF receptor double knockout (DKO) mice displayed similar changes in PIP as WT animals, whereas p75–/– TNF receptor knockout (p75KO) mice showed a more rapid increase and p55–/– TNF receptor knockout (p55KO) mice showed virtually no change. N = 11 for WT mice, and 9 for each of the other strains at the start of ventilation. Data points represent the mean of all surviving animals at each time point. Irregular changes of PIP and lack of 120-min samples in p75KO mice were due to early mortality. These different patterns of PIP changes among the mouse strains were confirmed by a significant interaction P value (P < 0.001) between mice strain and ventilation time in the linear mixed model analysis. B: PIP at the end of the protocol (regardless of duration). Dashed line represents PIP at start of ventilation protocol. N = 11 for WT mice, and 9 for each of the other strains. *P < 0.001 vs. WT, {dagger}P < 0.05 vs. DKO by 1-way ANOVA with Bonferroni tests.

 
Consistent with these changes in PIP, high stretch ventilation produced alterations in respiratory mechanics (Fig. 3), including an increase in Rrs and a decrease in Crs compared with the start of the high stretch protocol. The increase in Rrs was similar in WT, DKO, and p75KO mice but attenuated (P < 0.01) in p55KO mice compared with both WT and DKO animals. The decrease in Crs was similar in WT and DKO mice, greater in p75KO mice (P < 0.01 vs. WT), and attenuated in p55KO mice (P < 0.01 vs. WT and DKO). The development of high stretch-induced lung injury was also associated with functional impairments in gas exchange (Table 1). In WT, DKO, and p75KO mice, arterial PO2 levels decreased and PCO2 increased (P < 0.01) in samples taken at the end of the protocol compared with those taken after 60 min of high stretch (when PIP changes were negligible). In contrast, PO2 and PCO2 did not significantly change in p55KO animals.


Figure 3
View larger version (18K):
[in this window]
[in a new window]

  		Fig. 3. High stretch-induced changes in respiratory system resistance (A) and compliance (B) in WT and TNF receptor knockout mice. Changes are expressed as %increase at end of protocol compared with start value. N = 11 for WT mice, and 9 for each of the other strains. *P < 0.01 vs. WT, {dagger}P < 0.001 vs. DKO by 1-way ANOVA with Bonferroni tests.

 

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

  		Table 1. Blood gas parameters of WT and TNF receptor knockout mice during high stretch ventilation

 
We have previously found in mice ventilated with high stretch that when BP falls <45 mmHg in conjunction with increased PIP, then cardiorespiratory collapse due to severe pulmonary edema follows soon after, associated with reduced organ perfusion and profound metabolic acidosis (74). In the current experiments, we used mean BP <45 mmHg as a surrogate marker for mortality, which avoided any potential impact of such confounding variables on measured physiological and biochemical parameters, as demonstrated by a normal pH in all animals at the end of the experiments (Table 1). WT mice started to "die" at ~90 min, and only ~25% of the animals survived 2 h of ventilation (Fig. 4). This was similar in DKO mice, but occurred sooner in p75KO mice (after ~70 min), and no animals in this group reached 2 h of ventilation. In contrast, all p55KO mice completed the full 2-h period. Statistical analysis indicated that the survival curves were different among the mouse strains, i.e., between p75KO vs. WT and DKO (P < 0.05), p55KO vs. WT and DKO (P < 0.01), and p75KO vs. p55KO mice (P < 0.001).


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

  		Fig. 4. Mortality induced by high stretch ventilation in WT and TNF receptor knockout mice. BP <45 mmHg in conjunction with increased PIP was used as a surrogate for mortality. N = 11 for WT mice, and 9 for each of the other strains at the start of ventilation. {dagger}P < 0.05 and *P < 0.01 vs. WT and DKO, §P < 0.001 different from each other by log-rank tests.

 
The baseline respiratory mechanics values measured at the start of high stretch ventilation in all animals used in this study were not different among the mouse strains (Table 2), suggesting that the observed differences in their physiological responses to ventilation were unlikely to be due to any inherent lung parenchymal variability and more likely related to TNF signaling effects.


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

  		Table 2. Baseline values of Rrs and Crs at the start of high stretch ventilation in WT and TNF receptor knockout mice

 
Pulmonary edema and permeability. To assess formation of pulmonary edema, we determined lavage fluid protein content and lung wet:dry weight ratio at the end of the ventilation protocols. The degree of pulmonary edema was similar by either measure in WT, DKO, and p75KO animals, but attenuated (P < 0.01) in p55KO mice (Fig. 5). To determine whether the observed protection from edema in p55KO mice was related to improved pulmonary endothelial/epithelial barrier function, translocation of fluorescence-labeled albumin from blood to alveolar space was measured in separate experiments after just 60 min of ventilation (Fig. 6). This early time point was used to perform measurements in the absence of potentially confounding factors such as deteriorating BP and PO2 that would occur in the later stages of the experiments. Even at this early stage before changes in PIP became apparent, the lung permeability was increased by high stretch ventilation in WT mice, which was similar in DKO and p75KO mice, but significantly lower in high stretch-ventilated p55KO animals (P < 0.05).


Figure 5
View larger version (20K):
[in this window]
[in a new window]

  		Fig. 5. Pulmonary edema formation in WT and TNF receptor knockout mice assessed by lavage fluid protein content (A) (n = 7 for WT mice and 5 for each of the other strains) or lung wet:dry weight ratio (B) (n = 4 for each strain) at the end of high stretch ventilation protocols. *P < 0.01 vs. WT, {dagger}P < 0.01 vs. DKO by 1-way ANOVA with Bonferroni tests.

 

Figure 6
View larger version (17K):
[in this window]
[in a new window]

  		Fig. 6. Pulmonary endothelial/epithelial barrier permeability in WT and TNF receptor knockout mice assessed by lavage fluid:plasma ratio of Alexa Fluor 594-conjugated albumin, after 60 min of high stretch ventilation (before increases in PIP became apparent). Data from low stretch WT mice are shown as a dotted line for comparison. N = 7 for WT, and 5 for each of the other strains. *P < 0.05 vs. WT by 1-way ANOVA with Bonferroni tests.

 
Pulmonary inflammation. The cells recovered by lung lavage contained negligible amounts of neutrophils in any mouse strain (WT 2.1 ± 2.4, DKO 0.4 ± 0.2, p55KO 0.7 ± 0.4, p75KO 0.7 ± 0.6%), indicating that the ventilation period was not long enough to produce significant alveolar neutrophil infiltration. As we have previously observed that neutrophils are sequestered within the lung vasculature at a very early stage of VILI before alveolar migration (6), MPO activity was determined in lungs from WT and p55KO mice subjected to high stretch ventilation. There was no difference in MPO activity in samples from these mouse strains (Fig. 7), indicating that the protection from edema formation in p55KO mice was independent of the degree of neutrophil accumulation. In addition, no differences among any of the four strains were observed for the levels of neutrophil chemoattractants MIP-2 (WT 19.8 ± 10.3, DKO 10.7 ± 10.4, p55KO 12.4 ± 7.1, p75KO 10.4 ± 6.7 pg/ml) or KC (WT 100 ± 89, DKO 26 ± 15, p55KO 62 ± 67, p75KO 67 ± 67 pg/ml) in lavage fluid, all of which supports the likelihood that the effects observed were independent of any influence of TNF on neutrophil recruitment. Finally, TNF receptor levels were determined in lavage fluid of WT mice. Compared with nonventilated mice, high stretch ventilation promoted dramatic increases in the levels of both p55 and p75 receptors in lavage fluid (Fig. 8).


Figure 7
View larger version (14K):
[in this window]
[in a new window]

  		Fig. 7. Myeloperoxidase activity in lungs from WT and TNF receptor p55 knockout mice at the end of high stretch protocols. N = 5 for each strain. OD, optical density.

 

Figure 8
View larger version (8K):
[in this window]
[in a new window]

  		Fig. 8. Concentration of TNF receptors (p55 and p75) in lung lavage fluid from nonventilated or high stretch-ventilated WT mice. N = 3–5 for each group. *P < 0.001 vs. nonventilated animals by t-tests.

 

   DISCUSSION
TOP
 ABSTRACT
 METHODS
 RESULTS
 DISCUSSION
GRANTS
 REFERENCES
 
The present study demonstrated that TNF signaling plays a major role in the development of stretch-induced pulmonary edema during VILI, but the two types of TNF receptor signal in apparently opposing manners. Historically, there has been considerable controversy regarding the involvement of TNF in the development of the two primary pathologies of VILI, namely pulmonary edema, which starts early in the course of VILI, and pulmonary inflammation, involving neutrophil influx into the alveoli, which occurs at later stages (10, 11, 49). We previously found that anti-TNF treatment attenuated both edema formation and neutrophilic inflammation in a rabbit model of VILI induced by saline lavage followed by injurious ventilation (24), but interpretation of this study is complicated by the intrinsic difficulties in such "two-hit" models to separate the effects of ventilation from those of preexisting lung injury (10, 75). In addition, the large degree of neutrophil infiltration in this model makes it impossible to distinguish between neutrophil-dependent and -independent effects. More recently, we have demonstrated in mouse models of VILI, induced purely by high stretch ventilation in the absence of preexisting lung injury, that pulmonary neutrophil recruitment was attenuated by blockade of TNF signaling (75). Here we provide the first in vivo evidence of a role for TNF receptor I (p55) signaling in promoting stretch-induced pulmonary edema formation. In contrast, mice lacking TNF receptor II (p75) signaling showed increased susceptibility to edema formation, indicating a protective role for this receptor.

In the current study, we have used a modification of our previous mouse model of high tidal volume VILI (6, 74, 75) in which the experimental protocol was designed specifically to detect development of pulmonary edema (as represented by changes in PIP, respiratory mechanics, gas exchange, lavage fluid protein levels, and lung wet:dry ratio) before neutrophil infiltration. The ventilator settings were chosen to induce substantial edema in WT animals within a 2-h period, which was not long enough to upregulate expression of neutrophil chemoattractants in lavage fluid or to produce intra-alveolar neutrophil recruitment, but sufficiently long to induce intrapulmonary expression of bioactive TNF, as demonstrated by ourselves (74) and others (8, 22, 28, 51, 61, 62, 67, 68) using similar protocols. This protocol thus enabled assessment of the effects of TNF signaling on stretch-induced edema formation independently from its effects on neutrophilic inflammation, whereas in more prolonged models such separation would be much more difficult.

Consistent with previous reports by ourselves and others (75, 78), high stretch-induced pulmonary edema was not attenuated in mice lacking both TNF receptors (DKO), which behaved very similarly to WT animals. In complete contrast, mice lacking solely the p55 receptor were strongly protected from the edema-promoting effects of high stretch, whereas p75KO mice were more susceptible than the other strains. Since the current protocol was designed to evaluate most of the injury parameters at the end of experiments when WT animals displayed substantial injury, it is well suited to detect protective effects, but much less sensitive to injurious effects (as virtually all animals in the control and increased susceptibility groups will be severely injured when measurements are taken). Presumably, for this reason, p75KO animals exhibited differences from WT animals only in some of the terminally measured parameters (PIP and Crs), but not in others (PO2, lavage fluid protein, and lung wet:dry weight ratio). However, analyses of the time course of injury parameters provided statistically significant evidence of an increased susceptibility in p75KO mice, i.e., PIP increased more rapidly and death occurred sooner with no animals surviving the full 2-h protocol.

Rapidly developing, neutrophil-independent pulmonary edema induced by high stretch has traditionally been considered to be a result of mechanical disruption of the alveolar-capillary membrane, with little involvement of pulmonary inflammation. Although this may be the case with extremely acute (occurring in minutes) edema (9), it has been shown that certain inflammatory mediators such as TNF are upregulated within the alveoli sufficiently early in the course of VILI (74) to be involved in more gradually developing (occurring in hours) pulmonary edema. Our results clearly support an early involvement of inflammation in stretch-induced edema formation, with TNF playing a direct role. This occurred independently of its effect on neutrophil recruitment, as most apparent from the attenuated edema in p55KO mice despite similar lung MPO activity. The edema-promoting action of TNF in these experiments is mediated specifically through the p55 TNF receptor. The p55 receptor has historically been considered the predominant receptor for the cellular actions of TNF (71), with p75 proposed mainly as a modulator of p55 signaling, either cooperatively by ligand passing to p55 or negatively by the soluble receptor sequestering TNF and thus preventing binding to cell-associated p55 (32, 33, 71). However, if the only role for the p75 receptor was through modulating p55 signaling, we should expect TNF receptor DKO mice to be somewhat protected from injury as they lack both receptors, which was clearly not the case either here or as reported elsewhere (75, 78). Considering the increased susceptibility to high stretch ventilation in p75KO mice, and the fact that the DKO animals used were derived from crossing of the p55KO and p75KO animals and all three strains have a similar C57BL6 background, the data are better explained by p75 and p55 signaling having directly opposite effects, with p75 signaling impeding edema formation independently of p55. It is becoming clear that the two TNF receptors are indeed capable of signaling independently (27, 33, 43, 71), and directly opposing effects have been proposed in sepsis induced by cecal ligation and puncture (12) and in retinal ischemic injury (18), but not previously with relation to acute lung injury.

The mechanisms underlying the observed differential roles of the two TNF receptors are unclear, but there are several possibilities on which we may speculate. First, while TNF has been shown to induce impairment of endothelial and epithelial barrier function by promoting reorganization of the actin cytoskeleton (30, 38, 44, 45, 76, 77) predominantly through the p55 receptor (16), recent studies suggested that a tyrosine kinase pathway, Etk/BMX, activated by the p75 receptor (41), can improve epithelial barrier function by promoting a redistribution of actin filaments (23). Second, the aforementioned study of retinal ischemic injury (18) suggested that the protective effect of p75 signaling was mediated through the anti-apoptotic PkB/Akt pathway. High stretch ventilation has been demonstrated to activate Akt by phosphorylation (65), but the relevance of apoptosis to acutely progressing pulmonary edema in VILI is controversial. Third, the apparently protective effects of p75 TNF receptor signaling might be related to the stimulatory effect of TNF on alveolar fluid clearance (3, 13, 19), although potential involvement of each TNF receptor in this process has yet to be clarified. Fourth, TNF could be acting through downstream intermediates such as transforming growth factor-beta or vascular endothelial growth factor, both of which have been implicated in pulmonary edema formation (26, 58) and may be upregulated/augmented by TNF (29, 59). Finally, it is possible that the recently described processes of plasma membrane wounding and turnover (70) may play some role in the acute pulmonary edema formation, but it is unknown whether TNF is involved in modulating these.

The expression of TNF receptors within the lung and the affinity of each receptor to different forms of TNF likely play a role in determining which receptor TNF binds and activates during VILI. Both p55 and p75 receptors have been demonstrated to be present in lung tissue (14, 37), although the precise localization is unclear. Some studies suggest that alveolar epithelial cells express p55 only (37, 42, 47), whereas others demonstrate epithelial expression of both receptors (4, 31). The affinity of p75 receptor to soluble TNF at low concentrations is much greater than that of p55 (66), and it has been suggested that membrane-bound TNF signals mainly through p75 receptor (21). Therefore, during the course of high stretch-induced injury, TNF may signal initially through "protective" p75 (either by rapidly upregulated membrane TNF on TNF-expressing cells or by low local concentrations of soluble TNF) but later through "deleterious" p55 as concentrations of soluble TNF increase. In addition, shedding of TNF receptors within the alveoli would also influence TNF signaling. We demonstrate here for the first time that soluble TNF receptors of both types are dramatically increased in lavage fluid by high stretch ventilation. The physiological effects of this, as well as the cell sources, are as yet undetermined. Theoretically, increased soluble TNF receptor levels could either impede TNF signaling or prolong its biological half-life, and it is not yet clear whether the increased receptor levels in our study represent a protective or deleterious process. Increased soluble TNF receptor levels in both bronchoalveolar lavage and plasma have, however, been reported following nonprotective ventilation in ARDS patients and have been associated with worse outcome (42, 48).

In the current study, the VT used to produce VILI was much greater than would be used in the clinical setting in humans. However, the results should still give important insights into the pathophysiology of VILI, as the VT employed is similar to those used in previous in vivo and ex vivo animal studies in the literature (9, 25, 50, 61), which have substantially contributed to our understanding of the mechanisms of VILI. Moreover, as has been pointed out (54), the lung stretch induced by such volumes may not be dissimilar from that experienced clinically, as 40 ml/kg delivered to a healthy mouse lung may approximate the stretch induced by 10 ml/kg delivered to an injured human ARDS lung with only 25% aerated lung capacity. Finally, it may be entirely inappropriate to directly compare the absolute values of either VT or inspiratory pressure between mice and humans, as the mouse respiratory system is more compliant than other species with very different pressure-volume curves, such that intact mouse lungs can be temporarily inflated to pressures above 60 cmH2O, relating to a VT of 60–70 ml/kg, without reaching a traditionally defined total lung capacity or producing morphological damage (56).

Formation of permeability pulmonary edema is an important hallmark of VILI and ALI, determining the impairment of lung function and crucially influencing the clinical course of the diseases. Our findings indicate that in the current model of rapidly evolving VILI, TNF signaling strongly mediates stretch-induced pulmonary edema independently of its effects on neutrophil recruitment. As with all small animal models, the conditions used to create the model represent a balance between clinical relevance, practicality, and addressing the question posed, and therefore limitations may exist in extrapolating our results to more slowly evolving VILI models and/or clinical situations. In particular, since neutrophil infiltration is usually associated with VILI/ALI pathology in patients, the precise clinical implication of such neutrophil-independent effects of TNF signaling has yet to be determined. However, it is possible that the direct effects of TNF on lung permeability could be additive/synergistic with neutrophil-mediated effects in vivo. Moreover, the direct effects of TNF may play an important role in certain conditions of VILI and ALI, as evidenced by the observations that ALI can develop even in neutropenic patients (40) and that neutrophil recruitment per se does not necessarily induce ALI (34). Our results provide an important notion that TNF signaling affects stretch-induced pulmonary edema in a complex fashion, having direct effects on lung permeability that may be either positive or negative, in addition to generally negative indirect effects mediated by neutrophils in later stages.

The results of the present study may have further implications for the treatment of VILI and potentially ALI of other etiologies if differential TNF signaling is a common phenomenon. The demonstration of differential roles of TNF receptors suggests that total blockade of TNF signaling may be counterproductive for the treatment of VILI and that more targeted strategies may be necessary, such as specific blockade of p55 or upregulation of p75 signaling. Which of these targets would be most appropriate for intervention may vary during the progression of lung injury and depend on the importance of pulmonary edema in the pathophysiology at that stage. Our results may offer insights to reevaluate the generally negative outcome of previous studies of sepsis and ALI utilizing total TNF signaling blockade strategies (e.g., anti-TNF antibodies, TNF knockout, or TNF receptor DKO mice), as TNF involvement may have been masked by such differential receptor signaling.


   GRANTS
TOP
 ABSTRACT
 METHODS
 RESULTS
 DISCUSSION
 GRANTS
REFERENCES
 
This work was supported by Medical Research Council UK Grant G0000101 and Wellcome Trust Grant 057459.


   FOOTNOTES
 

Address for reprint requests and other correspondence: M. Takata, Dept. of Anaesthetics and Intensive Care, Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, United Kingdom (e-mail: m.takata{at}imperial.ac.uk)

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.


   REFERENCES
TOP
 ABSTRACT
 METHODS
 RESULTS
 DISCUSSION
 GRANTS
 REFERENCES
 

  1. Acute Respiratory Distress Syndrome Network. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. N Engl J Med 342: 1301–1308, 2000.[Abstract/Free Full Text]
  2. Bradford MM. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem 72: 248–254, 1976.[CrossRef][Web of Science][Medline]
  3. Braun C, Hamacher J, Morel DR, Wendel A, Lucas R. Dichotomal role of TNF in experimental pulmonary edema reabsorption. J Immunol 175: 3402–3408, 2005.[Abstract/Free Full Text]
  4. Burvall K, Palmberg L, Larsson K. Expression of TNFalpha and its receptors R1 and R2 in human alveolar epithelial cells exposed to organic dust and the effects of 8-bromo-cAMP and protein kinase A modulation. Inflamm Res 54: 281–288, 2005.[CrossRef][Web of Science][Medline]
  5. Calkins CM, Heimbach JK, Bensard DD, Song Y, Raeburn CD, Meng X, McIntyre RC Jr. TNF receptor I mediates chemokine production and neutrophil accumulation in the lung following systemic lipopolysaccharide. J Surg Res 101: 232–237, 2001.[CrossRef][Web of Science][Medline]
  6. Choudhury S, Wilson MR, Goddard ME, O'Dea KP, Takata M. Mechanisms of early pulmonary neutrophil sequestration in ventilator-induced lung injury in mice. Am J Physiol Lung Cell Mol Physiol 287: L902–L910, 2004.[Abstract/Free Full Text]
  7. Copland IB, Kavanagh BP, Engelberts D, McKerlie C, Belik J, Post M. Early changes in lung gene expression due to high tidal volume. Am J Respir Crit Care Med 168: 1051–1059, 2003.[Abstract/Free Full Text]
  8. Copland IB, Martinez F, Kavanagh BP, Engelberts D, McKerlie C, Belik J, Post M. High tidal volume ventilation causes different inflammatory responses in newborn versus adult lung. Am J Respir Crit Care Med 169: 739–748, 2004.[Abstract/Free Full Text]
  9. Dreyfuss D, Basset G, Soler P, Saumon G. Intermittent positive-pressure hyperventilation with high inflation pressures produces pulmonary microvascular injury in rats. Am Rev Respir Dis 132: 880–884, 1985.[Web of Science][Medline]
  10. Dreyfuss D, Ricard JD, Saumon G. On the physiologic and clinical relevance of lung-borne cytokines during ventilator-induced lung injury. Am J Respir Crit Care Med 167: 1467–1471, 2003.[Free Full Text]
  11. Dreyfuss D, Saumon G. Ventilator-induced lung injury: lessons from experimental studies. Am J Respir Crit Care Med 157: 294–323, 1998.[Web of Science][Medline]
  12. Ebach DR, Riehl TE, Stenson WF. Opposing effects of tumor necrosis factor receptor 1 and 2 in sepsis due to cecal ligation and puncture. Shock 23: 311–318, 2005.[CrossRef][Web of Science][Medline]
  13. Elia N, Tapponnier M, Matthay MA, Hamacher J, Pache JC, Brundler MA, Totsch M, De Baetselier P, Fransen L, Fukuda N, Morel DR, Lucas R. Functional identification of the alveolar edema reabsorption activity of murine tumor necrosis factor-alpha. Am J Respir Crit Care Med 168: 1043–1050, 2003.[Abstract/Free Full Text]
  14. Ermert M, Pantazis C, Duncker HR, Grimminger F, Seeger W, Ermert L. In situ localization of TNFalpha/beta, TACE and TNF receptors TNF-R1 and TNF-R2 in control and LPS-treated lung tissue. Cytokine 22: 89–100, 2003.[CrossRef][Web of Science][Medline]
  15. Ewart S, Levitt R, Mitzner W. Respiratory system mechanics in mice measured by end-inflation occlusion. J Appl Physiol 79: 560–566, 1995.[Abstract/Free Full Text]
  16. Ferrero E, Zocchi MR, Magni E, Panzeri MC, Curnis F, Rugarli C, Ferrero ME, Corti A. Roles of tumor necrosis factor p55 and p75 receptors in TNF-{alpha}-induced vascular permeability. Am J Physiol Cell Physiol 281: C1173–C1179, 2001.[Abstract/Free Full Text]
  17. Foda HD, Rollo EE, Drews M, Conner C, Appelt K, Shalinsky DR, Zucker S. Ventilator-induced lung injury upregulates and activates gelatinases and EMMPRIN: attenuation by the synthetic matrix metalloproteinase inhibitor, Prinomastat (AG3340). Am J Respir Cell Mol Biol 25: 717–724, 2001.[Abstract/Free Full Text]
  18. Fontaine V, Mohand-Said S, Hanoteau N, Fuchs C, Pfizenmaier K, Eisel U. Neurodegenerative and neuroprotective effects of tumor necrosis factor (TNF) in retinal ischemia: opposite roles of TNF receptor 1 and TNF receptor 2. J Neurosci 22: RC216, 2002.[Abstract/Free Full Text]
  19. Fukuda N, Jayr C, Lazrak A, Wang Y, Lucas R, Matalon S, Matthay MA. Mechanisms of TNF-alpha stimulation of amiloride-sensitive sodium transport across alveolar epithelium. Am J Physiol Lung Cell Mol Physiol 280: L1258–L1265, 2001.[Abstract/Free Full Text]
  20. Ghosh S, Wilson MR, Choudhury S, Yamamoto H, Goddard ME, Falusi B, Marczin N, Takata M. Effects of inhaled carbon monoxide on acute lung injury in mice. Am J Physiol Lung Cell Mol Physiol 288: L1003–L1009, 2005.[Abstract/Free Full Text]
  21. Grell M, Douni E, Wajant H, Lohden M, Clauss M, Maxeiner B, Georgopoulos S, Lesslauer W, Kollias G, Pfizenmaier K, Scheurich P. The transmembrane form of tumor necrosis factor is the prime activating ligand of the 80 kDa tumor necrosis factor receptor. Cell 83: 793–802, 1995.[CrossRef][Web of Science][Medline]
  22. Halbertsma FJ, Vaneker M, Scheffer GJ, van der Hoeven JG. Cytokines and biotrauma in ventilator-induced lung injury: a critical review of the literature. Neth J Med 63: 382–392, 2005.[Web of Science][Medline]
  23. Hamm-Alvarez SF, Chang A, Wang Y, Jerdeva G, Lin HH, Kim KJ, Ann DK. Etk/Bmx activation modulates barrier function in epithelial cells. Am J Physiol Cell Physiol 280: C1657–C1668, 2001.[Abstract/Free Full Text]
  24. Imai Y, Kawano T, Iwamoto S, Nakagawa S, Takata M, Miyasaka K. Intratracheal anti-tumor necrosis factor-{alpha} antibody attenuates ventilator-induced lung injury in rabbits. J Appl Physiol 87: 510–515, 1999.[Abstract/Free Full Text]
  25. Imanaka H, Shimaoka M, Matsuura N, Nishimura M, Ohta N, Kiyono H. Ventilator-induced lung injury is associated with neutrophil infiltration, macrophage activation, and TGF-beta 1 mRNA upregulation in rat lungs. Anesth Analg 92: 428–436, 2001.[Abstract/Free Full Text]
  26. Jenkins RG, Su X, Su G, Scotton CJ, Camerer E, Laurent GJ, Davis GE, Chambers RC, Matthay MA, Sheppard D. Ligation of protease-activated receptor 1 enhances {alpha}vbeta6 integrin-dependent TGF-beta activation and promotes acute lung injury. J Clin Invest 116: 1606–1614, 2006.[CrossRef][Web of Science][Medline]
  27. Jupp OJ, McFarlane SM, Anderson HM, Littlejohn AF, Mohamed AA, MacKay RH, Vandenabeele P, MacEwan DJ. Type II tumour necrosis factor-alpha receptor (TNFR2) activates c-Jun N-terminal kinase (JNK) but not mitogen-activated protein kinase (MAPK) or p38 MAPK pathways. Biochem J 359: 525–535, 2001.[CrossRef][Web of Science][Medline]
  28. Kornecki A, Tsuchida S, Ondiveeran HK, Engelberts D, Frndova H, Tanswell AK, Post M, McKerlie C, Belik J, Fox-Robichaud A, Kavanagh BP. Lung development and susceptibility to ventilator-induced lung injury. Am J Respir Crit Care Med 171: 743–752, 2005.[Abstract/Free Full Text]
  29. Koyama S, Sato E, Tsukadaira A, Haniuda M, Numanami H, Kurai M, Nagai S, Izumi T. Vascular endothelial growth factor mRNA and protein expression in airway epithelial cell lines in vitro. Eur Respir J 20: 1449–1456, 2002.[Abstract/Free Full Text]
  30. Lacherade JC, Van De Louw A, Planus E, Escudier E, D'Ortho MP, Lafuma C, Harf A, Delclaux C. Evaluation of basement membrane degradation during TNF-{alpha}-induced increase in epithelial permeability. Am J Physiol Lung Cell Mol Physiol 281: L134–L143, 2001.[Abstract/Free Full Text]
  31. Liu J, Zhao MQ, Xu L, Ramana CV, Declercq W, Vandenabeele P, Enelow RI. Requirement for TNF-R2 in alveolar chemokine expression depends upon the form of the ligand. Am J Respir Cell Mol Biol 33: 463–469, 2005.[Abstract/Free Full Text]
  32. MacEwan DJ. TNF ligands and receptors–a matter of life and death. Br J Pharmacol 135: 855–875, 2002.[CrossRef][Web of Science]
  33. MacEwan DJ. TNF receptor subtype signalling: differences and cellular consequences. Cell Signal 14: 477–492, 2002.[CrossRef][Web of Science][Medline]
  34. Martin TR. Neutrophils and lung injury: getting it right. J Clin Invest 110: 1603–1605, 2002.[CrossRef][Web of Science][Medline]
  35. Meduri GU, Kohler G, Headley S, Tolley E, Stentz F, Postlethwaite A. Inflammatory cytokines in the BAL of patients with ARDS. Persistent elevation over time predicts poor outcome. Chest 108: 1303–1314, 1995.[CrossRef][Web of Science][Medline]
  36. Mizgerd JP, Peschon JJ, Doerschuk CM. Roles of tumor necrosis factor receptor signaling during murine Escherichia coli pneumonia. Am J Respir Cell Mol Biol 22: 85–91, 2000.[Abstract/Free Full Text]
  37. Nakamura H, Hino T, Kato S, Shibata Y, Takahashi H, Tomoike H. Tumour necrosis factor receptor gene expression and shedding in human whole lung tissue and pulmonary epithelium. Eur Respir J 9: 1643–1647, 1996.[Abstract]
  38. Nwariaku FE, Rothenbach P, Liu Z, Zhu X, Turnage RH, Terada LS. Rho inhibition decreases TNF-induced endothelial MAPK activation and monolayer permeability. J Appl Physiol 95: 1889–1895, 2003.[Abstract/Free Full Text]
  39. O'Dea KP, Young AJ, Yamamoto H, Robotham JL, Brennan FM, Takata M. Lung-marginated monocytes modulate pulmonary microvascular injury during early endotoxemia. Am J Respir Crit Care Med 172: 1119–1127, 2005.[Abstract/Free Full Text]
  40. Ognibene FP, Martin SE, Parker MM, Schlesinger T, Roach P, Burch C, Shelhamer JH, Parrillo JE. Adult respiratory distress syndrome in patients with severe neutropenia. N Engl J Med 315: 547–551, 1986.[Abstract]
  41. Pan S, An P, Zhang R, He X, Yin G, Min W. Etk/Bmx as a tumor necrosis factor receptor type 2-specific kinase: role in endothelial cell migration and angiogenesis. Mol Cell Biol 22: 7512–7523, 2002.[Abstract/Free Full Text]
  42. Parsons PE, Matthay MA, Ware LB, Eisner MD. Elevated plasma levels of soluble TNF receptors are associated with morbidity and mortality in patients with acute lung injury. Am J Physiol Lung Cell Mol Physiol 288: L426–L431, 2005.[Abstract/Free Full Text]
  43. Peschon JJ, Torrance DS, Stocking KL, Glaccum MB, Otten C, Willis CR, Charrier K, Morrissey PJ, Ware CB, Mohler KM. TNF receptor-deficient mice reveal divergent roles for p55 and p75 in several models of inflammation. J Immunol 160: 943–952, 1998.[Abstract/Free Full Text]
  44. Petrache I, Birukova A, Ramirez SI, Garcia JG, Verin AD. The role of the microtubules in tumor necrosis factor-alpha-induced endothelial cell permeability. Am J Respir Cell Mol Biol 28: 574–581, 2003.[Abstract/Free Full Text]
  45. Petrache I, Verin AD, Crow MT, Birukova A, Liu F, Garcia JG. Differential effect of MLC kinase in TNF-{alpha}-induced endothelial cell apoptosis and barrier dysfunction. Am J Physiol Lung Cell Mol Physiol 280: L1168–L1178, 2001.[Abstract/Free Full Text]
  46. Pinhu L, Whitehead T, Evans T, Griffiths M. Ventilator-associated lung injury. Lancet 361: 332–340, 2003.[CrossRef][Web of Science][Medline]
  47. Pryhuber GS, Huyck HL, Staversky RJ, Finkelstein JN, O'Reilly MA. Tumor necrosis factor-alpha-induced lung cell expression of antiapoptotic genes TRAF1 and cIAP2. Am J Respir Cell Mol Biol 22: 150–156, 2000.[Abstract/Free Full Text]
  48. Ranieri VM, Suter PM, Tortorella C, De Tullio R, Dayer JM, Brienza A, Bruno F, Slutsky AS. Effect of mechanical ventilation on inflammatory mediators in patients with acute respiratory distress syndrome: a randomized controlled trial. JAMA 282: 54–61, 1999.[Abstract/Free Full Text]
  49. Ricard JD, Dreyfuss D. Cytokines during ventilator-induced lung injury: a word of caution. Anesth Analg 93: 251–252, 2001.[Free Full Text]
  50. Ricard JD, Dreyfuss D, Saumon G. Production of inflammatory cytokines in ventilator-induced lung injury: a reappraisal. Am J Respir Crit Care Med 163: 1176–1180, 2001.[Abstract/Free Full Text]
  51. Rich PB, Douillet CD, Hurd H, Boucher RC. Effect of ventilatory rate on airway cytokine levels and lung injury. J Surg Res 113: 139–145, 2003.[CrossRef][Web of Science][Medline]
  52. Sheridan BC, McIntyre RC Jr, Meldrum DR, Fullerton DA. L-arginine prevents lung neutrophil accumulation and preserves pulmonary endothelial function after endotoxin. Am J Physiol Lung Cell Mol Physiol 274: L337–L342, 1998.[Abstract/Free Full Text]
  53. Slutsky AS. Lung injury caused by mechanical ventilation. Chest 116: 9S–15S, 1999.[CrossRef]
  54. Slutsky AS, Tremblay LN. Multiple system organ failure. Is mechanical ventilation a contributing factor? Am J Respir Crit Care Med 157: 1721–1725, 1998.[Free Full Text]
  55. Song Y, Ao L, Raeburn CD, Calkins CM, Abraham E, Harken AH, Meng X. A low level of TNF-{alpha} mediates hemorrhage-induced acute lung injury via p55 TNF receptor. Am J Physiol Lung Cell Mol Physiol 281: L677–L684, 2001.[Abstract/Free Full Text]
  56. Soutiere SE, Mitzner W. On defining total lung capacity in the mouse. J Appl Physiol 96: 1658–1664, 2004.[Abstract/Free Full Text]
  57. Stuber F, Wrigge H, Schroeder S, Wetegrove S, Zinserling J, Hoeft A, Putensen C. Kinetic and reversibility of mechanical ventilation-associated pulmonary and systemic inflammatory response in patients with acute lung injury. Intensive Care Med 28: 834–841, 2002.[CrossRef][Web of Science][Medline]
  58. Su G, Hodnett M, Wu N, Atakilit A, Kosinski C, Godzich M, Huang XZ, Kim JK, Frank JA, Matthay MA, Sheppard D, Pittet JF. Integrin {alpha}vbeta5 regulates lung vascular permeability and pulmonary endothelial barrier function. Am J Respir Cell Mol Biol 36: 377–386, 2007.[Abstract/Free Full Text]
  59. Sullivan DE, Ferris M, Pociask D, Brody AR. Tumor necrosis factor-alpha induces transforming growth factor-beta1 expression in lung fibroblasts through the extracellular signal-regulated kinase pathway. Am J Respir Cell Mol Biol 32: 342–349, 2005.[Abstract/Free Full Text]
  60. Takata M, Abe J, Tanaka H, Kitano Y, Doi S, Kohsaka T, Miyasaka K. Intraalveolar expression of tumor necrosis factor-alpha gene during conventional and high-frequency ventilation. Am J Respir Crit Care Med 156: 272–279, 1997.[Abstract/Free Full Text]
  61. Tremblay L, Valenza F, Ribeiro SP, Li J, Slutsky AS. Injurious ventilatory strategies increase cytokines and c-fos m-RNA expression in an isolated rat lung model. J Clin Invest 99: 944–952, 1997.[Web of Science][Medline]
  62. Tremblay LN, Miatto D, Hamid Q, Govindarajan A, Slutsky AS. Injurious ventilation induces widespread pulmonary epithelial expression of tumor necrosis factor-alpha and interleukin-6 messenger RNA. Crit Care Med 30: 1693–1700, 2002.[CrossRef][Web of Science][Medline]
  63. Uhlig S, Ranieri M, Slutsky AS. Biotrauma hypothesis of ventilator-induced lung injury. Am J Respir Crit Care Med 169: 314–315; author reply 315, 2004.[Free Full Text]
  64. Uhlig S, Uhlig U. Pharmacological interventions in ventilator-induced lung injury. Trends Pharmacol Sci 25: 592–600, 2004.[CrossRef][Medline]
  65. Uhlig U, Fehrenbach H, Lachmann RA, Goldmann T, Lachmann B, Vollmer E, Uhlig S. Phosphoinositide 3-OH kinase inhibition prevents ventilation-induced lung cell activation. Am J Respir Crit Care Med 169: 201–208, 2004.[Abstract/Free Full Text]
  66. Vandenabeele P, Declercq W, Beyaert R, Fiers W. Two tumour necrosis factor receptors: structure and function. Trends Cell Biol 5: 392–399, 1995.[CrossRef][Web of Science][Medline]
  67. Veldhuizen RA, Slutsky AS, Joseph M, McCaig L. Effects of mechanical ventilation of isolated mouse lungs on surfactant and inflammatory cytokines. Eur Respir J 17: 488–494, 2001.[Abstract/Free Full Text]
  68. Veldhuizen RA, Tremblay LN, Govindarajan A, van Rozendaal BA, Haagsman HP, Slutsky AS. Pulmonary surfactant is altered during mechanical ventilation of isolated rat lung. Crit Care Med 28: 2545–2551, 2000.[CrossRef][Web of Science][Medline]
  69. Verbrugge SJ, Uhlig S, Neggers SJ, Martin C, Held HD, Haitsma JJ, Lachmann B. Different ventilation strategies affect lung function but do not increase tumor necrosis factor-alpha and prostacyclin production in lavaged rat lungs in vivo. Anesthesiology 91: 1834–1843, 1999.[CrossRef][Web of Science][Medline]
  70. Vlahakis NE, Hubmayr RD. Cellular stress failure in ventilator-injured lungs. Am J Respir Crit Care Med 171: 1328–1342, 2005.[Abstract/Free Full Text]
  71. Wajant H, Pfizenmaier K, Scheurich P. Tumor necrosis factor signaling. Cell Death Differ 10: 45–65, 2003.[CrossRef][Web of Science][Medline]
  72. Ware LB, Matthay MA. The acute respiratory distress syndrome. N Engl J Med 342: 1334–1349, 2000.[Free Full Text]
  73. Wiener-Kronish JP, Albertine KH, Matthay MA. Differential responses of the endothelial and epithelial barriers of the lung in sheep to Escherichia coli endotoxin. J Clin Invest 88: 864–875, 1991.[Web of Science][Medline]
  74. Wilson MR, Choudhury S, Goddard ME, O'Dea KP, Nicholson AG, Takata M. High tidal volume upregulates intrapulmonary cytokines in an in vivo mouse model of ventilator-induced lung injury. J Appl Physiol 95: 1385–1393, 2003.[Abstract/Free Full Text]
  75. Wilson MR, Choudhury S, Takata M. Pulmonary inflammation induced by high-stretch ventilation is mediated by tumor necrosis factor signaling in mice. Am J Physiol Lung Cell Mol Physiol 288: L599–L607, 2005.[Abstract/Free Full Text]
  76. Wojciak-Stothard B, Entwistle A, Garg R, Ridley AJ. Regulation of TNF-alpha-induced reorganization of the actin cytoskeleton and cell-cell junctions by Rho, Rac, and Cdc42 in human endothelial cells. J Cell Physiol 176: 150–165, 1998.[CrossRef][Web of Science][Medline]
  77. Yoo J, Nichols A, Song JC, Mammen J, Calvo I, Worrell RT, Cuppoletti J, Matlin K, Matthews JB. Bryostatin-1 attenuates TNF-induced epithelial barrier dysfunction: role of novel PKC isozymes. Am J Physiol Gastrointest Liver Physiol 284: G703–G712, 2003.[Abstract/Free Full Text]
  78. Yoshikawa S, King JA, Lausch RN, Penton AM, Eyal FG, Parker JC. Acute ventilator-induced vascular permeability and cytokine responses in isolated and in situ mouse lungs. J Appl Physiol 97: 2190–2199, 2004.[Abstract/Free Full Text]



This article has been cited by other articles:


Home page
 Am. J. Respir. Crit. Care Med.Home page
M. R. Wilson, K. P. O'Dea, D. Zhang, A. D. Shearman, N. van Rooijen, and M. Takata
Role of Lung-marginated Monocytes in an In Vivo Mouse Model of Ventilator-induced Lung Injury
Am. J. Respir. Crit. Care Med., May 15, 2009; 179(10): 914 - 922.
[Abstract] [Full Text] [PDF]

Home page
 PediatricsHome page
M. Vento, M. Aguar, T. A. Leone, N. N. Finer, A. Gimeno, W. Rich, P. Saenz, R. Escrig, and M. Brugada
Using Intensive Care Technology in the Delivery Room: A New Concept for the Resuscitation of Extremely Preterm Neonates
Pediatrics, November 1, 2008; 122(5): 1113 - 1116.
[Full Text] [PDF]

Home page
 Am. J. Physiol. Lung Cell. Mol. Physiol.Home page
T. Eckle, L. Fullbier, A. Grenz, and H. K. Eltzschig
Usefulness of pressure-controlled ventilation at high inspiratory pressures to induce acute lung injury in mice
Am J Physiol Lung Cell Mol Physiol, October 1, 2008; 295(4): L718 - L724.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
O. R. Rana, C. Zobel, E. Saygili, K. Brixius, F. Gramley, T. Schimpf, K. Mischke, D. Frechen, C. Knackstedt, R. H. G. Schwinger, et al.
A simple device to apply equibiaxial strain to cells cultured on flexible membranes
Am J Physiol Heart Circ Physiol, January 1, 2008; 294(1): H532 - H540.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
293/1/L60    most recent
00284.2006v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Web of Science (8)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Wilson, M. R.
Right arrow Articles by Takata, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Wilson, M. R.
Right arrow Articles by Takata, M.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online
Copyright © 2007 by the American Physiological Society.