1 Division of Pulmonary and Critical Care Medicine, Department of Medicine, The University of Michigan Medical School, Ann Arbor, Michigan 48109-0360; and 2 Department of Microbiology, Toho University, Tokyo 143-0015, Japan
![]() |
ABSTRACT |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Prostaglandins of the E series are believed to act as important mediators of several pathophysiological events that occur in sepsis. Studies were performed to evaluate the effect of cyclooxygenase (COX)-2-specific inhibition on the outcome in murine endotoxemia and cecal ligation and puncture (CLP). We observed a significant time-dependent upregulation of PGE2 production in both blood and lung homogenates of mice administered lipopolysaccharide intraperitoneally, which was nearly completely suppressed by the administration of the COX-2 inhibitor NS-398. Treatment with NS-398 significantly improved early but not late survival in lipopolysaccharide-challenged mice. On the contrary, elevated PGE2 levels were found in bronchoalveolar lavage fluid but not in plasma of mice subjected to CLP (21 gauge). Pretreatment with NS-398 failed to significantly improve survival in CLP mice. No significant differences were noted in plasma or lung homogenate proinflammatory cytokine levels or lung neutrophil sequestration between the NS-398-treated and control groups. These results demonstrate that selective COX-2 inhibition confers early but not long-term benefits without affecting the expression of proinflammatory cytokines or the development of lung inflammation.
prostaglandin E2; cyclooxygenase-2; cecal ligation and puncture; NS-398; sepsis
![]() |
INTRODUCTION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
SEPSIS IS A COMPLEX SYSTEMIC ILLNESS that is manifest by varying degrees of hypotension, coagulopathy, and multiorgan dysfunction (7). Despite advances in supportive care, the mortality rate in patients with severe sepsis continues to exceed 30%. The sepsis syndrome is associated with the unabated release of inflammatory mediators, including cytokines, chemokines, and eicosanoids, which often results in detrimental effects to the host (7, 14). Previous animal and human studies (2, 15) have demonstrated elevated levels of prostanoids in both experimental and clinical sepsis syndrome. PGE2 is one of the most potent and inducible of the prostanoids produced in states of inflammation. PGE2, produced by the metabolism of arachidonic acid by the enzyme cyclooxygenase (COX), is believed to be an important modulator of several of the observed events in sepsis. Specifically, there is evidence to support roles for PGE2 as a mediator of sepsis-induced immunosuppression, an inhibitor of proinflammatory cytokine expression from monocytes, and an inducer of interleukin (IL)-10 production (24, 25). Conversely, PGE2 has been shown to mediate detrimental effects in sepsis, including vasodilation and increased vascular permeability (19). In addition, its role as a mediator in fever induction and augmentation of pain is well established (16). Several reports (1, 5, 11, 13, 27) utilizing endotoxin-challenged animal studies have shown beneficial effects with nonselective COX inhibitors. These beneficial effects were felt to be mediated, in part, by the mitigation of the pathophysiological events in sepsis induced by prostaglandins.
COX exists as two isoforms, COX-1 and COX-2. COX-1 is constitutively
expressed, whereas COX-2 is expressed at low levels in most normal
resting cells. Marked upregulation of COX-2 occurs in synoviocytes,
macrophages, and endothelial cells during stress and in inflammatory
conditions such as sepsis. COX-2 expression is induced by a number of
cytokines including tumor necrosis factor (TNF)- and IL-1, mitogens
or growth factors, lipopolysaccharide (LPS), and other inflammatory
stimuli (9). Recent studies (16, 17, 22)
have provided evidence pointing to significant advantages in
the use of selective COX-2 inhibitors over their nonselective counterparts. The specific benefits of COX-2 inhibitors include decreased gastrointestinal toxicity and bleeding (17, 23).
The purpose of this study was to determine the role of COX-2 in the pathogenesis of sepsis by employing two murine models of sepsis: intraperitoneal LPS administration and cecal ligation and puncture (CLP). The effects of selective COX-2 inhibition on prostaglandin and cytokine production, temperature regulation, lung neutrophil sequestration, and survival were examined.
![]() |
MATERIALS AND METHODS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Reagents. NS-398 (N-[2-(cyclohexyloxy)-4-nitrophenyl]-methanesulfonamide; Cayman Chemical, Ann Arbor, MI) was prepared by dissolving the compound in DMSO. CD-1 mice were administered NS-398 intraperitoneally in 40 µl of DMSO at a dose of 15 mg/kg at designated time intervals. LPS (Escherichia coli type 0111:B4, Sigma) was diluted in sterile normal saline and sonicated before each administration. Polyclonal anti-murine TNF, IL-10, IL-12, KC, and macrophage inflammatory protein (MIP)-2 antibodies used in the ELISAs were produced by immunization of rabbits with murine recombinant cytokines with complete Freund's adjuvant at multiple intradermal sites. Carrier-free murine recombinant cytokines were purchased from R&D Systems (Minneapolis, MN). Purified antibodies for ELISA were obtained by purification over an endotoxin-free protein A column.
Animals. Specific pathogen-free CD-1 mice (6- to 12-wk females; Charles River Breeding Laboratories) were used in all experiments. CD-1 mice were chosen because the CLP and endotoxemia models have been well characterized in this outbred strain. All mice were housed in specific pathogen-free conditions within the animal care facility at the University of Michigan (Ann Arbor, MI) until the day of death.
Animal model of abdominal sepsis. CLP with either a 21- or 25-gauge needle was used as model of systemic sepsis syndrome as previously described (26). In distinct contrast to CLP models with larger-gauge cecal punctures (19 gauge and larger), in which most animals rapidly develop bacteremia due to enteric organisms and death occurs as a result of polymicrobial sepsis, CLP with a 21- or 25-gauge needle results in the development of bacteremia in a minority of the animals (11). However, this insult induces a marked septic response, with death occurring in ~20-30% of animals with a 25-gauge needle and 40-60% mortality with a 21-gauge needle compared with a mortality rate of >90% in mice undergoing 18-gauge CLP (26). To perform this procedure, pathogen-free female CD-1 mice were anesthetized with pentobarbital sodium (50 mg/kg ip; Butler, Columbus, OH) followed by inhaled methoxyflurane (Metafane, Pitman-Moore, Mundelein, IL) as needed. In these mice, a 1- to 2-cm longitudinal incision to the lower right quadrant of the abdomen was performed, and the cecum was exposed. The distal one-third of the cecum was ligated with a 3-0 silk suture and punctured through and through with either a 21- or 25-gauge needle. A small amount of the bowel contents was then extruded through the puncture site. The cecum was replaced in the peritoneal cavity, and the incision was closed with surgical staples. In sham control animals, the cecum was exposed but not ligated or punctured and then returned to the abdominal cavity. All mice were administered 1 ml of sterile saline subcutaneously for fluid resuscitation during the postoperative period.
PGE2 and thromboxane B2 extraction and
analysis.
PGE2 and thromboxane (TX) B2 were extracted
from bronchoalveolar lavage (BAL) fluid, whole lung homogenates, and
plasma with C18 Sep-Pak cartridges (Waters Associates,
Milford, MA) as previously described (18). The extracts
were evaporated to dryness under nitrogen and stored at 80°C.
Before analysis, the extracts were resuspended in cell culture medium
and assayed for PGE2 and TXB2 with an enzyme
immunoassay kit (Cayman Chemical).
Core body temperature determination. Rectal temperature (as a measure of core body temperature) was determined at baseline and at predetermined time points post-LPS administration with a model 49 TA digital thermometer equipped with a YSI series 400 probe (2-mm diameter; Yellow Springs Instruments, Yellow Springs, OH). Before temperature measurement, the probe was coated with Surgilube lubricant (Division of Atlanta, Melville, NY) and inserted ~1.5-2 cm into the rectum.
Murine cytokine ELISAs.
Murine TNF, IL-10, IL-12, KC, and MIP-2 were quantitated with a
modification of a double-ligand method as previously described (26). Briefly, flat-bottomed 96-well microtiter plates
(Nunc Immuno-Plate I 96-F) were coated with 50 µl/well of rabbit
antibody against the various cytokines (1 µg/ml in 0.6 M NaCl, 0.26 M
H3BO4, and 0.08 M NaOH, pH 9.6) for 16 h
at 4°C and then washed with PBS, pH 7.5, and 0.05% Tween 20 (wash
buffer). Microtiter plate nonspecific binding sites were blocked with
2% BSA in PBS and incubated for 90 min at 37°C. The plates were
rinsed four times with wash buffer, and diluted (neat and 1:10)
cell-free supernatants (50 µl) were added in duplicate followed by
incubation for 1 h at 37°C. The plates were washed four times
followed by the addition of 50 µl/well of biotinylated rabbit
antibodies against the specific cytokines (3.5 µg/ml in PBS, pH 7.5, 0.05% Tween 20, and 2% FCS), and the plates were incubated for 30 min
at 37°C. The plates were washed four times, streptavidin-peroxidase
conjugate (Bio-Rad Laboratories, Richmond, CA) was added, and the
plates were incubated for 30 min at 37°C. The plates were washed
again four times, and chromogen substrate (Bio-Rad Laboratories) was
added. The plates were incubated at room temperature to the desired
extinction, and the reaction was terminated with 50 µl/well of a 3 M
H2SO4 solution. The plates were read at 490 nm
in an ELISA reader. The standards were 1:2 log dilutions of recombinant
murine cytokines from 1 pg/ml to 100 ng/ml. This ELISA method
consistently detected murine cytokine concentrations >25 pg/ml. The
ELISAs did not cross-react with IL-1, IL-2, IL-4, or IL-6. In addition,
the ELISAs did not cross-react with other members of the murine
chemokine family, including murine JE/monocyte chemoattractant
protein-1, regulated on activation normal T cell expressed and
secreted, growth-related gene-, or epithelial cell-derived
neutrophil-activating protein-78.
Lung myeloperoxidase assay. Lung myeloperoxidase (MPO) activity (as an assessment of neutrophil influx) was quantitated by a method previously described (21). Briefly, whole lungs were homogenized in 2 ml of a solution containing 50 mM potassium phosphate, pH 6.0, 5% hexadecyltrimethylammonium bromide, and 5 mM EDTA. One hundred microliters of the resulting homogenate were sonicated and centrifuged at 12,000 rpm for 15 min. The supernatant was mixed 1:15 with assay buffer and read at 490 nm. MPO units were calculated as the change in absorbance over time.
Statistical analysis. Data were analyzed with the Prism 3.0 statistical program (GraphPad Software, San Diego, CA). Survival data were compared with Fisher's exact test. All data are expressed as means ± SE. Comparisons between two experimental groups of data were performed with Student's unpaired t-test. Comparisons among three or more experimental groups were performed with ANOVA followed by Dunnett's test. Data were considered significant if P values were <0.05.
![]() |
RESULTS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Production of PGE2 in murine endotoxemia.
Experiments were first performed to assess the time-dependent
production of PGE2 in murine endotoxemia. CD-1 mice were
challenged with 250 µg of LPS intraperitoneally, and then the
PGE2 levels were determined in plasma and lungs at multiple
time points after LPS administration. As shown in Figs.
1 and 2,
LPS administration resulted in a rapid increase in PGE2
levels, peaking at 6 h in plasma (Fig. 1) and lung homogenates
(Fig. 2) and returning to baseline levels by 12 h. Similarly, LPS
administration resulted in the induction of TXB2 (the
stable metabolite of TXA2) in lung homogenates, which was
maximal 6 h post-LPS challenge (26,800 ± 4,812 pg/ml in
LPS-treated animals compared with 4,678 ± 501 pg/ml in
vehicle-treated animals; P < 0.01).
|
|
Effect of NS-398 on PGE2 production after LPS administration. After demonstrating elevated levels of PGE2 in plasma and lung homogenates after LPS administration, CD-1 mice were administered NS-398 intraperitoneally at varying doses, and PGE2 levels were assessed in these same compartments. NS-398 at a dose of 15 mg/kg administered 2 h before LPS administration, 4 h later, and every 12 h thereafter completely suppressed production of PGE2 in plasma (Fig. 1) and lungs (Fig. 2) to baseline levels. The suppressive effects of NS-398 were maintained at a dose of 10 mg/kg (data not shown). In addition, we observed equivalent suppression of PGE2 whether NS-398 was administered at the same time as or 2 h before LPS administration (data not shown). Furthermore, treatment with NS-398 resulted in a 45% reduction in maximal TXB2 levels in lung homogenates after LPS administration (data not shown).
COX-2 inhibition significantly reduces early but not late
endotoxin-induced mortality.
Experiments were performed to determine the effects of COX-2 inhibition
on the mortality in mice administered LPS. For mortality studies, a
dose of 700 µg LPS/animal was used, a dose that represented an
~80% lethal dose in control animals. As shown in Fig.
3, pretreatment of animals with NS-398
2 h before LPS administration, 4 h later, and every 12 h
thereafter resulted in 95% survival at 24 h, whereas only 65%
survival was observed in animals administered vehicle alone
(P < 0.05). Survival after 24 h, however, was not
significantly different between the two groups, although a trend toward
improved survival was noted in the NS-398-treated animals. No effect of vehicle (DMSO) was observed because survival in animals challenged with
LPS alone was identical to that observed in mice administered vehicle
plus LPS (data not shown).
|
Effect of COX-2 inhibition on gross motor activity and temperature
regulation.
We next assessed the effect of NS-398 administration on gross motor
activity and rectal temperature in LPS-treated mice. CD-1 mice were
administered either vehicle or NS-398 15 mg/kg 2 h before LPS
administration, 4 h later, and every 12 h thereafter. The mice administered vehicle were more lethargic and displayed decreased oral intake and substantially more piloerection compared with NS-398-treated mice. As shown in Fig. 4,
mice receiving vehicle alone had significant elevations in body
temperature 1 and 2 h post-LPS administration followed by a drop
in core temperature thereafter. In contrast, no early increase in core
temperature was observed in mice treated with NS-398 before LPS
administration, although the decrease in temperature by 6 h was
similar to that observed in control animals.
|
PGE2 inhibition does not alter cytokine production
after LPS administration.
Inflammatory cytokines and chemokines have previously been shown to
modulate many of the observed events in endotoxemia (20, 28). Moreover, PGE2 is known to suppress the
inflammatory cytokines IL-12, TNF-, and IL-1 and several of the
chemokines in vitro. We performed experiments examining the role of
COX-2 inhibition on the expression of proinflammatory cytokines during
endotoxemia. CD-1 mice were pretreated with NS-398 (15 mg/kg) or
vehicle 2 h before and 4 h after the intraperitoneal
administration of LPS (500 µg), and then plasma was collected at
designated time points post-LPS. As shown in Fig.
5, endotoxin challenge resulted in peak
increases in plasma TNF-
levels in control animals at 2 h, with
levels decreasing to baseline by 6 h after LPS. Likewise, endotoxin challenge resulted in peak increases in plasma levels of the
C-X-C chemokine KC in both groups between 4 and 6 h after LPS.
Importantly, there were no significant differences in TNF-
and KC
between NS-398-treated mice and control mice at any time point. In
addition, there was no significant change in the levels of other
relevant cytokines, including IL-12 and IL-10, and the C-X-C chemokine
MIP-2 (data not shown).
|
Pretreatment with NS-398 does not alter lung polymorphonuclear
neutrophil sequestration after LPS administration.
Experiments were next performed to assess the effects of
COX-2 inhibition on lung polymorphonuclear neutrophil sequestration after LPS challenge. Mice were treated with either vehicle or NS-398
2 h before endotoxin challenge, and then lung MPO activity (as a
measure of neutrophil sequestration) was determined 2 and 6 h
after LPS. As shown in Fig. 6, challenge
with LPS (500 µg) resulted in a significant increase in lung MPO
activity 2 and 6 h after LPS compared with that in
saline-challenged animals. Treatment with NS-398 did not alter the
LPS-induced increase in lung MPO activity at either time point after
LPS, indicating that the early protective effects of COX-2 inhibition
in endotoxemia were not a result of attenuation of lung
polymorphonuclear neutrophil sequestration.
|
Production of PGE2 in bacterial peritonitis.
Experiments were next performed to define the production of
PGE2 in a more clinically relevant model of sepsis, namely
the CLP model. CD-1 mice underwent 21-gauge CLP, and PGE2
levels were then determined in plasma and lungs at multiple time points
after CLP. CLP resulted in no significant change in PGE2 in
plasma (Fig. 7) or lung homogenates (data
not shown). However, a small but significant increase in
PGE2 in BAL fluid was observed 12 h post-CLP, with a
return to baseline by 24 h. We observed no induction of TxB2 levels in lung, BAL fluid, or plasma of animals
undergoing CLP (data not shown).
|
Inhibition of COX-2 does not improve survival in CLP.
Our initial studies provided evidence that COX-2 inhibition in animals
challenged with LPS resulted in early survival benefits. Additional
studies were performed to examine the effects of NS-398 administration
on the survival of animals with abdominal sepsis. In these studies,
CD-1 mice were subjected to either 21- or 25-gauge CLP. Mice were
pretreated with NS-398 (15 mg/kg) 2 h before CLP, 4 h after
CLP, and every 12 h thereafter. As shown in Fig.
8, COX-2 inhibition resulted in a trend
toward decreased mortality in 21-gauge CLP compared with animals
receiving vehicle (P = 0.2). In animals undergoing
25-gauge CLP, mortality rates between the two groups were nearly
identical. Additionally, treatment of 21-gauge CLP mice with NS-398 had
no effect on peripheral blood leukocyte counts, the number of
peritoneal fluid leukocytes, and peritoneal fluid bacterial
colony-forming units compared with those in CLP animals receiving
vehicle (data not shown).
|
![]() |
DISCUSSION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
A number of studies have examined the role of nonselective COX inhibitors both in animal models of sepsis and in patients with and sepsis syndrome. Several studies (1, 5, 11, 13, 27) have demonstrated beneficial effects of nonselective COX inhibition, predominantly in endotoxin-treated animals. However, subsequent studies (3, 6) examining the role of nonsteroidal anti-inflammatory drugs, particularly ibuprofen, in human sepsis trials have been disappointing. Bolus LPS administration is not thought to be representative of clinically observed sepsis syndrome compared with the CLP model. Therefore, experiments were performed examining the effects of COX-2 inhibition in both endotoxin-challenged animals and animals undergoing CLP.
This is the first study, to our knowledge, that has examined the effects of specific COX-2 inhibition on the outcome in experimental models of endotoxemia and bacterial peritonitis. A recent study (22) examined the effects of NS-398 in a murine burn model of sepsis. In that study, a significant survival benefit was observed in burn-infected mice. In addition, restoration of total white blood cell counts and absolute neutrophil counts to baseline in leukopenic and neutropenic animals was observed. Futaki et al. (12), using a rat endotoxin model, observed upregulation of COX-2 mRNA after LPS administration, which was inhibited with NS-398 pretreatment. Induction of COX-2 and the resultant increase in PGE2 are observed in the generation of local and systemic inflammatory responses, although their exact functional significance remains uncertain. Existing evidence supports both anti- and proinflammatory actions of PGE2 in the setting of sepsis.
COX-2 inhibitors offer several potential theoretical advantages over nonselective COX inhibitors in the treatment of inflammatory disorders such as sepsis. These agents have been shown to produce less gastric toxicity than their nonselective counterparts. This may be especially important in critically ill patients who are at significantly greater risk for developing gastric ulceration. In addition, the lack of inhibitory actions on platelet function by COX-2-selective compounds may decrease the incidence of bleeding complications. On the contrary, COX-2 inhibitors may potentially lead to detrimental effects not seen with the nonselective COX inhibitors. In a recent report of four patients with connective tissue diseases (10), an increased incidence of thrombosis was documented in patients administered COX-2 inhibitors. In addition, COX-2 inhibitors have not been shown to provide significant renal protective effects over nonselective inhibitors.
We observed significant early survival benefits in LPS-challenged mice treated with NS-398. Survival benefits were associated with lessened lethargy, piloerection, and blunting of the hyperthermic response post-LPS. Although physiological parameters such as blood pressure and heart rate were not obtained in this study, we suspect that the early improvements in survival in NS-398-treated mice were due to improved hemodynamics. This is most likely given the physiological changes noted above and the fact that early mortality in endotoxin-challenged mice is largely attributed to hemodynamic instability rather than to end-organ injury (20). Importantly, we failed to observe any effects of NS-398 on the generation of pulmonary inflammation in endotoxin-treated mice or peritoneal inflammation in CLP mice. Peritoneal inflammation was assessed by quantitating total peritoneal leukocyte cell numbers and specific cell types 12 and 24 h post-CLP and were found not to be significantly different between the two groups (data not shown). The lack of effects on inflammatory cell influx was not due to incomplete inhibition of COX-2 activity because we observed a rather profound inhibition of PGE2 in NS-398-treated mice at all time points examined. These observations validate the use of NS-398 as an inhibitor of inducible PGE2 production. We also found that selective COX-2 inhibitors result in decreases in TXB2 production in endotoxin-challenged animals.
Cytokine profiles from murine models of sepsis, LPS administration and
CLP, have been well characterized previously (20). The
effects of selective COX-2 inhibition on cytokine production during
experimental sepsis syndrome has not been examined previously. It would
be predicted based on previous predominantly in vitro studies
(24, 25) that inhibition of PGE2 would
result in increased production of various proinflammatory cytokines
such as TNF- and IL-12. Contrary to these observations, our results
are similar to a previous report (8) that failed to
observe a significant change in systemic cytokine and chemokine levels
during nonsteroidal anti-inflammatory drug administration in
LPS-induced sepsis.
Treatment of mice with NS-398 resulted in early benefits in murine endotoxemia but not in CLP. There are several possible explanations for the disparity in the effects observed. First, we detected substantial induction of PGE2 in endotoxin-challenged mice but rather limited production of PGE2 in animals undergoing CLP. This is likely attributable to differences in the magnitude of systemic exposure to endotoxin and inflammatory cytokines, which is much more pronounced in animals challenged with bolus LPS than the more delayed and limited release in animals undergoing CLP. Also, the cause of mortality in CLP is multifactorial, and the degree to which bacteria are contained within the abdominal cavity partially dictates survival in these animals. In contrast to the findings made in a rat burn infection model, we did not observe any differences in bacterial clearance as assessed by culturing peritoneal fluid 12 and 24 h post-CLP and determining bacterial colony-forming units from the peritoneal cavity in NS-398-treated mice undergoing CLP compared with those in control animals. Likewise, we found no alteration in the clearance of Klebsiella pneumoniae from the lungs of NS-398-treated mice using a murine gram-negative pneumonia model (data not shown). Thus, as opposed to regulation of the 5-lipoxygenase pathway, our data suggest that regulation of the COX-2 pathway has little impact on localized antibacterial host responses (4).
In summary, selective inhibition of COX-2 results in improvement in early survival in murine endotoxemia but not in a more physiologically relevant model of abdominal sepsis (CLP). The early improvement in survival in endotoxin-challenged animals was not attributable to changes in inflammatory cytokine expression or organ-specific neutrophil sequestration. Selective inhibition of COX-2 in sepsis requires further study. However, the findings reported here are disappointing, particularly given the lack of benefit observed in animals with abdominal sepsis.
![]() |
ACKNOWLEDGEMENTS |
---|
This work was supported by National Heart, Lung, and Blood Institute Grants HL-57243 and P50-HL-60289.
![]() |
FOOTNOTES |
---|
Address for reprint requests and other correspondence: T. J. Standiford, The Univ. of Michigan Medical Center, Dept. of Internal Medicine, Division of Pulmonary and Critical Care Medicine, 6301 MSRB III, 1150 W. Medical Center Dr., Ann Arbor, MI 48109-0642 (E-mail: tstandif{at}umich.edu).
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.
Received 11 October 2000; accepted in final form 28 February 2001.
![]() |
REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
1.
Almqvist, PM,
Kuenzig M,
and
Schwartz SI.
Treatment of experimental canine endotoxin shock with ibuprofen, a cyclooxygenase inhibitor.
Circ Shock
13:
227-232,
1984[ISI][Medline].
2.
Anderson, FL,
Jubiz W,
Tsagaris TJ,
and
Kuida H.
Endotoxin-induced prostaglandin E and F release in dogs.
Am J Physiol
228:
410-414,
1975[ISI][Medline].
3.
Arons, MM,
Wheeler AP,
Bernard GR,
Christman BW,
Russell JA,
Schein R,
Summer WR,
Steinberg KP,
Fulkerson W,
Wright P,
Dupont WD,
and
Swindell BB.
Effects of ibuprofen on the physiology and survival of hypothermic sepsis. Ibuprofen in Sepsis Study Group.
Crit Care Med
27:
699-707,
1999[ISI][Medline].
4.
Bailie, MB,
Standiford TJ,
Laichalk LL,
Coffey MJ,
Strieter R,
and
Peters-Golden M.
Leukotriene-deficient mice manifest enhanced lethality from Klebsiella pneumonia in association with decreased alveolar macrophage phagocytic and bactericidal activities.
J Immunol
157:
5221-5224,
1996[Abstract].
5.
Beamer, KC,
Daly T,
and
Vargish T.
Hemodynamic evaluation of ibuprofen in canine hypovolemic shock.
Circ Shock
23:
51-57,
1987[ISI][Medline].
6.
Bernard, GR,
Wheeler AP,
Russell JA,
Schein R,
Summer WR,
Steinberg KP,
Fulkerson WJ,
Wright PE,
Christman BW,
Dupont WD,
Higgins SB,
and
Swindell BB.
The effects of ibuprofen on the physiology and survival of patients with sepsis. The Ibuprofen in Sepsis Study Group.
N Engl J Med
336:
912-918,
1997
7.
Bone, RC.
Sepsis and its complications: the clinical problem.
Crit Care Med
22:
S8-S11,
1994[ISI][Medline].
8.
Coran, AG,
Drongowski RA,
Paik JJ,
and
Remick DG.
Ibuprofen intervention in canine septic shock: reduction of pathophysiology without decreased cytokines.
J Surg Res
53:
272-279,
1992[ISI][Medline].
9.
Crofford, LJ,
Lipsky PE,
Brooks P,
Abramson SB,
Simon LS,
and
van de Putte LB.
Basic biology and clinical application of specific cyclooxygenase-2 inhibitors.
Arthritis Rheum
43:
4-13,
2000[ISI][Medline].
10.
Crofford, LJ,
Oates JC,
McCune WJ,
Gupta S,
Kaplan MJ,
Catella-Lawson F,
Morrow JD,
McDonagh KT,
and
Schmaier AH.
Thrombosis in patients with connective tissue diseases treated with specific cyclooxygenase 2 inhibitors. A report of four cases.
Arthritis Rheum
43:
1891-1896,
2000[ISI][Medline].
11.
Emau, P,
Giri SN,
Bruss ML,
and
Zia S.
Ibuprofen prevents Pasteurella hemolytica endotoxin-induced changes in plasma prostanoids and serotonin, and fever in sheep.
J Vet Pharmacol Ther
8:
352-361,
1985[ISI][Medline].
12.
Futaki, N,
Takahashi S,
Kitagawa T,
Yamakawa Y,
Tanaka M,
and
Higuchi S.
Selective inhibition of cyclooxygenase-2 by NS-398 in endotoxin shock rats in vivo.
Inflamm Res
46:
496-502,
1997[ISI][Medline].
13.
Jacobs, ER,
Soulsby ME,
Bone RC,
Wilson FJ, Jr,
and
Hiller FC.
Ibuprofen in canine endotoxin shock.
J Clin Invest
70:
536-541,
1982[ISI][Medline].
14.
Karzai, W,
and
Reinhart K.
Sepsis: definitions and diagnosis.
Int J Clin Pract Suppl
95:
44-48,
1998[Medline].
15.
Kessler, E,
Hughes RC,
Bennett EN,
and
Nadela SM.
Evidence for the presence of prostaglandin-like material in the plasma of dogs with endotoxin shock.
J Lab Clin Med
81:
85-94,
1973[ISI][Medline].
16.
Lipsky, PE.
Specific COX-2 inhibitors in arthritis, oncology, and beyond: where is the science headed?
J Rheumatol
26, Suppl56:
25-30,
1999[ISI][Medline].
17.
Lipsky, PE,
and
Isakson PC.
Outcome of specific COX-2 inhibition in rheumatoid arthritis.
J Rheumatol
24, Suppl49:
9-14,
1997[ISI][Medline].
18.
Peters-Golden, M,
McNish RW,
Hyzy R,
Shelly C,
and
Toews GB.
Alterations in the pattern of arachidonate metabolism accompany rat macrophage differentiation in the lung.
J Immunol
144:
263-270,
1990
19.
Portanova, JP,
Zhang Y,
Anderson GD,
Hauser SD,
Masferrer JL,
Seibert K,
Gregory SA,
and
Isakson PC.
Selective neutralization of prostaglandin E2 blocks inflammation, hyperalgesia, and interleukin 6 production in vivo.
J Exp Med
184:
883-891,
1996[Abstract].
20.
Remick, DG,
Newcomb DE,
Bolgos GL,
and
Call DR.
Comparison of the mortality and inflammatory response of two models of sepsis: lipopolysaccharide vs. cecal ligation and puncture.
Shock
13:
110-116,
2000[ISI][Medline].
21.
Remick, DG,
Strieter RM,
Eskandari MK,
Nguyen DT,
Genord MA,
Raiford CL,
and
Kunkel SL.
Role of tumor necrosis factor-alpha in lipopolysaccharide-induced pathologic alterations.
Am J Pathol
136:
49-60,
1990[Abstract].
22.
Shoup, M,
He LK,
Liu H,
Shankar R,
and
Gamelli R.
Cyclooxygenase-2 inhibitor NS-398 improves survival and restores leukocyte counts in burn infection.
J Trauma
45:
215-220,
1998[ISI][Medline].
23.
Simon, LS,
Lanza FL,
Lipsky PE,
Hubbard RC,
Talwalker S,
Schwartz BD,
Isakson PC,
and
Geis GS.
Preliminary study of the safety and efficacy of SC-58635, a novel cyclooxygenase 2 inhibitor: efficacy and safety in two placebo-controlled trials in osteoarthritis and rheumatoid arthritis, and studies of gastrointestinal and platelet effects.
Arthritis Rheum
41:
1591-1602,
1998[ISI][Medline].
24.
Strassmann, G,
Patil-Koota V,
Finkelman F,
Fong M,
and
Kambayashi T.
Evidence for the involvement of interleukin 10 in the differential deactivation of murine peritoneal macrophages by prostaglandin E2.
J Exp Med
180:
2365-2370,
1994[Abstract].
25.
Van der Pouw Kraan, TC,
Boeije LC,
Smeenk RJ,
Wijdenes J,
and
Aarden LA.
Prostaglandin-E2 is a potent inhibitor of human interleukin 12 production.
J Exp Med
181:
775-779,
1995[Abstract].
26.
Walley, KR,
Lukacs NW,
Standiford TJ,
Strieter RM,
and
Kunkel SL.
Balance of inflammatory cytokines related to severity and mortality of murine sepsis.
Infect Immun
64:
4733-4738,
1996[Abstract].
27.
Wise, WC,
Cook JA,
Eller T,
and
Halushka PV.
Ibuprofen improves survival from endotoxic shock in the rat.
J Pharmacol Exp Ther
215:
160-164,
1980[Abstract].
28.
Zisman, DA,
Kunkel SL,
Strieter RM,
Gauldie J,
Tsai WC,
Bramson J,
Wilkowski JM,
Bucknell KA,
and
Standiford TJ.
Anti-interleukin-12 therapy protects mice in lethal endotoxemia but impairs bacterial clearance in murine Escherichia coli peritoneal sepsis.
Shock
8:
349-356,
1997[ISI][Medline].