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K J Tracey

Publications and source records attributed to K J Tracey.

At least 37 records · Page 2Linked to original sources
PubMed2000

HMG-1 as a mediator of acute lung inflammation.

Acute inflammatory lung injury is often a delayed complication of critical illness and is associated with increased mortality. High mobility group-1 (HMG-1) protein, in addition to its role as a transcriptional regulatory factor, has recently been identified as a late mediator of endotoxin lethality. In the present studies, HMG-1 given intratracheally produced acute inflammatory injury to the lungs, with neutrophil accumulation, the development of lung edema, and increased pulmonary production of IL-1beta, TNF-alpha, and macrophage-inflammatory protein-2. In endotoxin-induced acute lung inflammation, administration of anti-HMG-1 Abs either before or after endotoxin exposure decreased the migration of neutrophils to the lungs as well as lung edema. These protective effects of anti-HMG-1 were specific, because pulmonary levels of IL-1beta, TNF-alpha, or macrophage-inflammatory protein-2 were not decreased after therapy with anti-HMG-1. Together, these findings indicate that HMG-1 is a distal mediator of acute inflammatory lung injury.

Adjuvants, Immunologic↗
PubMed2000

High mobility group 1 protein (HMG-1) stimulates proinflammatory cytokine synthesis in human monocytes.

Lipopolysaccharide (LPS) is lethal to animals because it activates cytokine release, causing septic shock and tissue injury. Early proinflammatory cytokines (e.g., tumor necrosis factor [TNF] and interleukin [IL]-1) released within the first few hours of endotoxemia stimulate mediator cascades that persist for days and can lead to death. High mobility group 1 protein (HMG-1), a ubiquitous DNA-binding protein, was recently identified as a "late" mediator of endotoxin lethality. Anti-HMG-1 antibodies neutralized the delayed increase in serum HMG-1, and protected against endotoxin lethality, even when passive immunization was delayed until after the early cytokine response. Here we examined whether HMG-1 might stimulate cytokine synthesis in human peripheral blood mononuclear cell cultures. Addition of purified recombinant HMG-1 to human monocyte cultures significantly stimulated the release of TNF, IL-1alpha, IL-1beta, IL-1RA, IL-6, IL-8, macrophage inflammatory protein (MIP)-1alpha, and MIP-1beta; but not IL-10 or IL-12. HMG-1 concentrations that activated monocytes were within the pathological range previously observed in endotoxemic animals, and in serum obtained from septic patients. HMG-1 failed to stimulate cytokine release in lymphocytes, indicating that cellular stimulation was specific. Cytokine release after HMG-1 stimulation was delayed and biphasic compared with LPS stimulation. Computer-assisted image analysis demonstrated that peak intensity of HMG-1-induced cellular TNF staining was comparable to that observed after maximal stimulation with LPS. Administration of HMG-1 to Balb/c mice significantly increased serum TNF levels in vivo. Together, these results indicate that, like other cytokine mediators of endotoxin lethality (e.g., TNF and IL-1), extracellular HMG-1 is a regulator of monocyte proinflammatory cytokine synthesis.

Animals↗
PubMed2000

Vagus nerve stimulation attenuates the systemic inflammatory response to endotoxin.

Vertebrates achieve internal homeostasis during infection or injury by balancing the activities of proinflammatory and anti-inflammatory pathways. Endotoxin (lipopolysaccharide), produced by all gram-negative bacteria, activates macrophages to release cytokines that are potentially lethal. The central nervous system regulates systemic inflammatory responses to endotoxin through humoral mechanisms. Activation of afferent vagus nerve fibres by endotoxin or cytokines stimulates hypothalamic-pituitary-adrenal anti-inflammatory responses. However, comparatively little is known about the role of efferent vagus nerve signalling in modulating inflammation. Here, we describe a previously unrecognized, parasympathetic anti-inflammatory pathway by which the brain modulates systemic inflammatory responses to endotoxin. Acetylcholine, the principle vagal neurotransmitter, significantly attenuated the release of cytokines (tumour necrosis factor (TNF), interleukin (IL)-1beta, IL-6 and IL-18), but not the anti-inflammatory cytokine IL-10, in lipopolysaccharide-stimulated human macrophage cultures. Direct electrical stimulation of the peripheral vagus nerve in vivo during lethal endotoxaemia in rats inhibited TNF synthesis in liver, attenuated peak serum TNF amounts, and prevented the development of shock.

Acetylcholine↗
PubMed2000

Thermal hyperalgesia and mechanical allodynia produced by intrathecal administration of the human immunodeficiency virus-1 (HIV-1) envelope glycoprotein, gp120.

Astrocytes and microglia in the spinal cord have recently been reported to contribute to the development of peripheral inflammation-induced exaggerated pain states. Both lowering of thermal pain threshold (thermal hyperalgesia) and lowering of response threshold to light tactile stimuli (mechanical allodynia) have been reported. The notion that spinal cord glia are potential mediators of such effects is based on the disruption of these exaggerated pain states by drugs thought to preferentially affect glial function. Activation of astrocytes and microglia can release many of the same substances that are known to mediate thermal hyperalgesia and mechanical allodynia. The aim of the present series of studies was to determine whether exaggerated pain states could also be created in rats by direct, intraspinal immune activation of astrocytes and microglia. The immune stimulus used was peri-spinal (intrathecal, i.t.) application of the Human Immunodeficiency Virus type 1 (HIV-1) envelope glycoprotein, gp120. This portion of HIV-1 is known to bind to and activate microglia and astrocytes. Robust thermal hyperalgesia (tail-flick, TF, and Hargreaves tests) and mechanical allodynia (von Frey and touch-evoked agitation tests) were observed in response to i.t. gp120. Heat denaturing of the complex protein structure of gp120 blocked gp120-induced thermal hyperalgesia. Lastly, both thermal hyperalgesia and mechanical allodynia to i.t. gp120 were blocked by spinal pretreatment with drugs (fluorocitrate and CNI-1493) thought to preferentially disrupt glial function.

Animals↗
PubMed2000

Regulation of macrophage activation and inflammation by spermine: a new chapter in an old story.

Spermine, a naturally occurring polyamine, is a ubiquitous structural component of all eukaryotic cells. Regenerating tissues produce higher levels of spermine, and injured or dying cells release spermine into the extracellular milieu, so that tissue levels increase significantly at inflammatory sites of infection or injury. Recent research has focused on delineating the significance of spermine accumulation in the inflammatory process. The discovery that spermine is a negative regulator of macrophage activation provided a mechanism by which spermine influences the biology of inflammation. Mechanistic studies indicate that spermine is incorporated into macrophages and restrains the innate immune response. This anti-inflammatory process is facilitated by the negative acute-phase protein, fetuin.

Humans↗
PubMed2000

Inhibition of p38 mitogen activate kinase attenuates the severity of pancreatitis-induced adult respiratory distress syndrome.

OBJECTIVE: Adult respiratory distress syndrome (ARDS) is responsible for a significant portion of the morbidity and mortality during severe acute pancreatitis. Because inflammatory mediators such as tumor necrosis factor (TNF)-alpha and nitric oxide (NO) produced within the lungs have been implicated in sepsis-induced ARDS, we aimed to determine the role of these mediators in pancreatitis-induced ARDS using a model whereby ascites from animals with pancreatitis is transferred to otherwise healthy animals resulting in pulmonary injury. DESIGN: Prospective, randomized, controlled trial. SETTING: Research laboratory at a university medical school. SUBJECTS: Pathogen-free Sprague-Dawley rats weighing 225-250 g. INTERVENTIONS: Sterile, endotoxin- and cytokine-free pancreatic ascites tested for interleukin (IL)-1beta , TNF-alpha, interferon-gamma, and IL-6 was obtained from rats 18 hrs after the induction of severe, acute pancreatitis. Ascites was subsequently administered intravenously (20 mL/kg) to healthy rats. Sham animals were administered intravenous saline. Healthy animals administered intravenous ascites were randomized to receive a single intraperitoneal injection of the p38 mitogen activated kinase inhibitor CNI-1493 (1 mg/kg) or vehicle. MEASUREMENTS: Pulmonary injury was assessed at 24 hrs by histology and leukocyte and protein concentrations via bronchoalveolar lavage. Pulmonary TNF-alpha protein was detected by immunohistochemistry. Serum nitrite, as a measure of NO production, was measured utilizing the Griess reaction. MAIN RESULTS: After the intravenous administration of pancreatic ascites, the number of leukocytes and the protein concentration within the bronchoalveolar fluid were increased and pulmonary histology was worsened consistent with acute lung injury (all p < .001 vs. sham). Each of these variables of pulmonary injury was lessened in animals receiving CNI-1493 and intravenous ascites (p < .05 vs. vehicle). Pulmonary TNF-alpha protein and serum nitrites were decreased with the administration of CNI-1493 (p < .005 vs. vehicle). CONCLUSIONS: A component of pancreatic ascites other than endotoxin, bacteria, or cytokines (IL-1beta, TNF, interferon-gamma, or IL-6) is capable of inducing ARDS in healthy animals. Inhibition of p38 mitogen activated kinase decreases the pulmonary injury through attenuated production of TNF-alpha and NO suggesting a primary role for these mediators in pancreatitis-induced ARDS.

Analysis of Variance↗
PubMed2000

Suppression of macrophage activation with CNI-1493 increases survival in infant rats with systemic Haemophilus influenzae infection.

CNI-1493, a potent macrophage deactivator, was used to treat infant rats systemically infected with Haemophilus influenzae type b (Hib). CNI-1493 was injected 1 h prior to bacterial inoculation and 24 h later and resulted in a 75 percent increased rate of survival compared to that for untreated controls. The effect of CNI-1493 on the inflammatory response was studied by immunohistochemical detection of individual tumor necrosis factor alpha (TNF-alpha)-, interleukin 1 beta (IL-1beta)-, and gamma interferon (IFN-gamma)-producing cells in the spleen. A significant reduction of the incidence of TNF-alpha- and IL-1beta-expressing cells was found for CNI-1493-treated animals. IFN-gamma expression was not suppressed by CNI-1493, indicating that cytokine inhibition was specific in macrophages. CNI-1493 significantly reduced the number of infiltrating granulocytes in the brain from that for controls. This study provides evidence that CNI-1493 protects against lethal Hib infection by deactivating the inflammatory cascade in infant rats.

Animals↗
PubMed1999

HMG-1 as a late mediator of endotoxin lethality in mice.

Endotoxin, a constituent of Gram-negative bacteria, stimulates macrophages to release large quantities of tumor necrosis factor (TNF) and interleukin-1 (IL-1), which can precipitate tissue injury and lethal shock (endotoxemia). Antagonists of TNF and IL-1 have shown limited efficacy in clinical trials, possibly because these cytokines are early mediators in pathogenesis. Here a potential late mediator of lethality is identified and characterized in a mouse model. High mobility group-1 (HMG-1) protein was found to be released by cultured macrophages more than 8 hours after stimulation with endotoxin, TNF, or IL-1. Mice showed increased serum levels of HMG-1 from 8 to 32 hours after endotoxin exposure. Delayed administration of antibodies to HMG-1 attenuated endotoxin lethality in mice, and administration of HMG-1 itself was lethal. Septic patients who succumbed to infection had increased serum HMG-1 levels, suggesting that this protein warrants investigation as a therapeutic target.

Animals↗
PubMed1999

Role of interleukin (IL)-2 receptor beta-chain subdomains and Shc in p38 mitogen-activated protein (MAP) kinase and p54 MAP kinase (stress-activated protein Kinase/c-Jun N-terminal kinase) activation. IL-2-driven proliferation is independent of p38 and p54 MAP kinase activation.

We have shown recently that interleukin (IL)-2 activates the mitogen-activated protein (MAP) kinase family members p38 (HOG1/stress-activated protein kinase II) and p54 (c-Jun N-terminal kinase/stress-activated protein kinase I). Furthermore, the p38 MAP kinase inhibitor SB203580 inhibited IL-2-driven T cell proliferation, suggesting that p38 MAP kinase might be involved in mediating proliferative signals. In this study, using transfected BA/F3 cell lines, it is shown that both the acidic domain and the membrane-proximal serine-rich region of the IL-2Rbeta chain are required for p38 and p54 MAP kinase activation and that, as for p42/44 MAP kinase, this activation requires the Tyr338 residue of the acidic domain, the binding site for Shc. It is well established that the acidic domain of the IL-2Rbeta chain is dispensable for IL-2-driven proliferation, and thus our observations suggest that neither p38 nor p54 MAP kinase activation is required for IL-2-driven proliferation of BA/F3 cells. In addition, the tetravalent guanylhydrazone inhibitor of proinflammatory cytokine production, CNI-1493, can block the activation of p54 and p38 MAP kinases by IL-2 but has no effect on IL-2-driven proliferation of BA/F3 cells, activated primary T cells, or a cytotoxic T cell line. Furthermore, our observations provide evidence for the existence of an additional, unknown target of the p38 MAP kinase inhibitor SB203580, the activation of which is essential for mitogenic signaling by IL-2.

Animals↗
PubMed1999

Anti-inflammatory effects of a new tumour necrosis factor-alpha (TNF-alpha) inhibitor (CNI-1493) in collagen-induced arthritis (CIA) in rats.

A recently developed compound, a multivalent guanylhydrazone (CNI-1493) that inhibits TNF-alpha production by suppressing TNF-alpha translational efficiency, was administered in an experimental model of collagen type II-induced arthritis in DA rats. CNI-1493 was injected daily intraperitoneally either before the onset of arthritis or after the establishment of clinical disease. Prophylactic treatment with CNI-1493 significantly prevented or delayed the onset and suppressed the severity of arthritis in a dose-dependent manner. Therapeutic intervention with CNI-1493 in established joint disease also resulted in a significant reduction of clinical signs of arthritis in treated animals. No severe side-effects were noted when animals were treated with daily CNI-1493 doses up to 5 mg/kg. An immunohistochemical study was performed which demonstrated that CNI-1493 led to a reduced expression of TNF-alpha at the site of disease activity. Thus, CNI-1493 with documented inhibitory effects on TNF-alpha synthesis, has proven successful in ameliorating the course of arthritis in CIA. We believe that the use of a compound such as CNI-1493 with a defined mode of action provides a useful tool for dissecting and understanding important pathogenic mechanisms operating in the development of chronic arthritis.

Animals↗
PubMed1999

Prevention of lethality and suppression of proinflammatory cytokines in experimental septic shock by microencapsulated CNI-1493.

CNI-1493, a newly developed, water-soluble tetravalent guanylhydrazone, is a powerful inhibitor of tumor necrosis factor (TNF) and interleukin-1 (IL-1) synthesis. Microencapsulation of drugs into microcapsules that target macrophages has improved the effectiveness of both TNF and IL-1 neutralizing antibodies in experimental models of septic shock. It is the purpose of this study to determine if microencapsulation of CNI-1493 will improve cytokine inhibition. CNI-1493 was microencapsulated using albumin into 1 microm spheres. Comparable amounts of CNI-1493 in solution and in microencapsulated form were added to 1 ml aliquots of whole blood along with 100 ng of endotoxin. TNF and IL-1 were measured by ELISA. Microencapsulated CNI-1493 was also given to rats with endotoxic shock (15 mg/kg Escherichia coli endotoxin) and rats with peritonitis induced by peritoneally injecting 10(10) CFU E. coli. Equivalent amounts of encapsulated and solution CN I-493 were given intravenously. Endotoxin 15 mg/kg was also given to rats 6 and 24 h after a dose of encapsulated CNI-1493 to determine the duration of action of encapsulated drug. The microencapsulated CNI-1493 produced significantly greater inhibition of TNF and IL-1 at all doses in the whole blood model. There was significantly improved survival and cytokine inhibition in the endotoxic shock model as well as the peritonitis model in rats treated with microencapsulated CNI-1493. There was also 83% survival in rats given endotoxin 24 h after a dose of encapsulated CNI-1493. From these data, we conclude that CNI-1493 is a potent inhibitor of cytokine production and is greatly potentiated by microencapsulation, which transports the drug to macrophages.

Animals↗
PubMed1999

Tolerance to shock: an exploration of mechanism.

OBJECTIVE: To determine if cross-tolerance to septic shock could be induced by a previous insult with sublethal hemorrhage (SLH) and to characterize the mechanisms involved in this induced protective response. BACKGROUND DATA: It is possible to condition animals by prior SLH such that they tolerate an otherwise lethal hemorrhage. It is also possible to condition animals with low doses of lipopolysaccharide (LPS) so that they survive a "lethal" septic insult. However, a paucity of information exists on cross-tolerance between hemorrhage and sepsis. METHODS: Rats were made tolerant by conditioning SLH or sham operation. Twenty-four hours later, tolerant and sham rats were exposed to a lethal dose of LPS. To explore the mechanism of tolerance induction, rats were given the macrophage (Mphi) inhibitor CNI-1493 or saline carrier before SLH. Survival and pulmonary vascular injury were determined after LPS. Serum tumor necrosis factor (TNF) levels and splenic Mphi TNF gene expression were measured at several time points. RESULTS: Prior SLH indeed made rats tolerant and imparted a significant survival benefit and reduction in pulmonary vascular injury after LPS. The tolerance induced by SLH was reversed by Mphi inhibition. Tolerant animals had low serum TNF levels immediately after SLH and reduced circulating TNF levels after LPS. SLH, however, did not inhibit the augmentation of TNF gene expression after LPS. CONCLUSIONS: Sublethal hemorrhage bestows protection against a lethal LPS challenge. Inhibition of the Mphi attenuated the benefit of the tolerance induced by SLH. Circulating TNF but not TNF gene after LPS is lessened by SLH. This implicates changes in Mphi intracellular signaling in induction of the tolerant state.

Animals↗
PubMed1999

Loss of NF-kappaB activity during cerebral ischemia and TNF cytotoxicity.

Recent evidence implicates tumor necrosis factor (TNF), a cytokine with both cytotoxic and cytoprotective activities, in the pathogenesis of cerebral ischemia. The development of TNF cytotoxicity is dependent upon the balance between the activities of intracellular signaling pathways that mediate either apoptotic or anti-apoptotic effects. One critical protective signaling mechanism is the activation of nuclear factor (NF)-kappaB, a ubiquitous transcription factor that regulates expression of anti-apoptotic gene products. Here we show the distribution and kinetics of NF-kappaB activation and the correlation between loss of NF-kappaB activity, TNF up-regulation, and apoptosis in a standardized rat model of focal cerebral ischemia. We observed a rapid and progressive ischemia-induced loss of p65 immunoreactivity within the ischemic core and nearby penumbra. These findings were confirmed by Western blot analysis of nuclear extracts and by electrophoretic mobility shift assay. The anatomical area of suppressed NF-kappaB activity overlapped significantly with the zones of TNF overexpression and apoptosis. Loss of NF-kappaB activity and increased TNF expression preceded the onset of cell death. Direct evidence that loss of NF-kappaB activity can sensitize brain cells to TNF cytotoxicity was obtained in vitro by co-administration of MG-132, an inhibitor of NF-kappaB activation, and TNF to neuronal-like and glial-like cell cultures. Inhibition of NF-kappaB significantly increased the sensitivity of these cultures to TNF cytotoxicity, indicating that the observed loss of neuronal NF-kappaB activity during cerebral ischemia can participate in the development of TNF-induced cytotoxicity.

Animals↗
PubMed1999

Evidence of a central role for p38 map kinase induction of tumor necrosis factor alpha in pancreatitis-associated pulmonary injury.

BACKGROUND: Tumor necrosis factor alpha (TNF alpha) has been implicated as an important mediator in acute pancreatitis-associated adult respiratory distress syndrome, but the precise pathogenesis remains unclear. The purpose of this work was to clarify the role of TNF alpha that is produced within the lung parenchyma in the inducement of pancreatitis-related pulmonary injury and to examine 1 of the potential pathways leading to the production of pulmonary TNF alpha. METHODS: Bile salt pancreatitis was induced in rats (n = 40) that were randomized to receive a p38 mitogen-activated protein (MAP) kinase inhibitor or vehicle. A separate group (n = 16) underwent sham operation. Pulmonary capillary permeability was determined with fluorescein isothiocyanate-labeled albumin and Evans blue dye, and lung histologic analysis was performed. TNF alpha protein was measured in bronchoalveolar lavage fluid, and p38 MAP kinase was activity determined by Western blot analysis. RESULTS: The induction of pancreatitis resulted in increased pulmonary capillary leakage and worsened histologic condition (P < .01 vs sham). Effective inhibition of p38 MAP kinase-induced TNF alpha production completely prevented pancreatitis-associated pulmonary injury (P < .01 vs vehicle). CONCLUSIONS: p38 MAP kinase-induced TNF alpha production plays a central role in the development of pulmonary dysfunction, which accompanies severe acute pancreatitis in this rodent model.

Acute Disease↗
PubMed1999

Proinflammatory cytokines (tumor necrosis factor and interleukin 1) stimulate release of high mobility group protein-1 by pituicytes.

BACKGROUND: Cytokines mediate the metabolic and physiologic responses to injury and infection. Anterior pituitary cells express receptors for tumor necrosis factor (TNF) and interleukin 1 (IL-1), which can signal these cells to release corticotropin, growth hormone, and cytokines such as IL-1 and macrophage migration inhibitory factor. This interaction provides an important link between the immune system and the neuroendocrine system. We reasoned that pituicytes activated with TNF or IL-1 might release previously unrecognized factors that could participate in this signaling from the neuroendocrine to the immune system. METHODS: Proteins released from rat pituicytes (GH3) after stimulation with proinflammatory cytokines were identified by N-terminal amino acid sequencing. Polyclonal antibodies against a peptide corresponding to the N-terminal amino acid sequence were generated and used to determine the kinetics of protein release. RESULTS: Cytokine stimulation induced the release of a 30-kd protein from rat pituicytes. After the protein was isolated and the N-terminal amino acid sequence determined, a protein database analysis revealed that it is high mobility group-1 (HMG-1) protein. TNF and IL-1 induced the release of HMG-1 from pituicytes in a time- and dose-dependent manner. Interferon gamma alone did not induce the release of HMG-1, but it enhanced TNF-induced HMG-1 release. CONCLUSION: Stimulation of pituicytes by TNF or IL-1 induces the release of HMG-1, which may participate in the regulation of neuroendocrine and immune responses to infection or injury.

Amino Acid Sequence↗
PubMed1999

Spermine inhibition of monocyte activation and inflammation.

The innate immune system functions as a defensive front line against pathogenic invasion, but the proinflammatory products of activated monocytes and macrophages (e.g., TNF and NO) can also injure normal cells. Anti-inflammatory mediators restrain the innate immune response and prevent excessive collateral tissue damage. Spermine, a ubiquitous biogenic polyamine, specifically and reversibly suppresses the synthesis of monocyte proinflammatory cytokines. This may provide a counterregulatory mechanism to restrain monocyte activation in injured or infected tissues and in tumors where spermine levels are significantly increased. Here we show that monocyte spermine uptake was significantly increased following lipopolysaccharide stimulation. The polyamine analogue 1, 4-bis(3-aminopropyl)-piperazine (BAP) inhibited LPS-stimulated monocyte spermine uptake via the "nonselective" polyamine transporter. BAP fully restored macrophage TNF synthesis despite the presence of spermine, indicating that the mechanism of monocyte deactivation by spermine is dependent on spermine uptake. Administration of BAP in vivo significantly augmented the development of carrageenan-induced paw edema and nitric oxide release. Thus, endogenous spermine normally inhibits the innate inflammatory response by restraining macrophages.

Animals↗