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R M Strieter

Publications and source records attributed to R M Strieter.

At least 181 records · Page 10Linked to original sources
PubMed1996

Activation and regulation of chemokines in allergic airway inflammation.

Allergic airway inflammation is characterized by peribronchial eosinophil accumulation with the submucosa surrounding the airway. The initial induction of immunoglobulin E (IgE)-mediated mast cell degranulation, up-regulation of adhesion molecules, and the production of inflammatory and chemotactic cytokines, leading to the infiltration of specific leukocyte subsets, is orchestrated in a sequential manner. The activation and degranulation of local mast cell populations is an immediate airway response mediated both by antigen-specific, surface bound IgE and by cytokine-induced activational pathways. Subsequently the infiltration and activation of effector leukocytes (neutrophils and eosinophils) mediated by the persistent activation of allergen-specific T cells leads to pathological manifestations within the lung and airway. The development of appropriate animal models to dissect the critical mechanisms involved in antigen-induced airway pathology is crucial for the development of efficacious therapies. We have utilized a model of allergic airway inflammation induced by intratracheal challenge with parasite (Schistosoma mansoni) egg antigen in presensitized mice. This model has proven useful in the assessment of eosinophil recruitment and has identified key cytokines involved in leukocyte elicitation. These cytokines include interleukin-4 and elicitation. These cytokines include interleukin-4 and tumor necrosis factor, which appear to act as early response mediators, as well as C-C chemokines, macrophage inflammatory protein-1a, and RANTES, which act directly on eosinophil recruitment. In addition, we have found that both C-X-C and C-C chemokines are expressed in pulmonary-derived mast cells, suggesting an important contribution to leukocyte responses in the allergic airway.

Animals↗
PubMed1996

Expression and regulation of chemokines in bacterial pneumonia.

Effective host defense against bacterial invasion is characterized by the vigorous recruitment and activation of inflammatory cells which is dependent on the coordinated expression of both pro and anti-inflammatory cytokines. In this review, we present evidence indicating that both C-X-C and C-C chemokines are integral components of antibacterial host defense. Specifically, in vitro studies indicate that C-X-C chemokines [interleukin-8 (IL-8) and macrophage inflammatory protein 2 (MIP-2) and the C-C chemokine macrophage inflammatory protein 1 alpha (MIP-1 alpha) augment the ability of polymorphonuclear leukocytes (PMNs) and alveolar macrophages, respectively, to phagocytose and kill Escherichia coli. In addition, the intratracheal instillation of Klebsiella pneumoniae in CD-1 mice results in time-dependent production of MIP-2 and MIP-1 alpha and the inhibition of MIP-2 bioactivity in vivo results in decreases in lung PMN influx, impaired bacterial clearance, and early mortality. Finally, the anti-inflammatory cytokine interleukin-10 (IL-10) is also expressed within the lung during the evolution of Klebsiella pneumonia, and neutralization of IL-10 in vivo results in enhanced proinflammatory cytokine production, bacterial clearance, and increases in both short- and long-term survival. In conclusion, our studies indicate that specific chemokines are important mediators of leukocyte recruitment and/or activation in bacterial pneumonia and that the expression of these chemokines is regulated by endogenously produced IL-10.

Animals↗
PubMed1996

The role of chemokines in inflammatory joint disease.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by the elicitation and activation of a number of leukocyte populations within both the synovial space and joint tissue. The recruited leukocytes subsequently play an instrumental role in synovial cell proliferation, pannus formation, and bone erosion. Although it is know that leukocytes are important participants in the evolving joint pathology, the mechanism responsible for the successful elicitation of cells to the joint is not clear. A number of studies have identified an association of specific cytokines, including chemokines, with active arthritis, but longitudinal analyses of cytokine expression and the causal role of these mediators have not been defined. Animal models and cell culture systems have proved useful in identifying the expression of various cytokines during the maintenance of chronic joint inflammation. In addition, animal models have provided important information regarding the kinetic production and contribution of specific mediators to the development of experimental arthritis. These studies provide insights into the potential mechanisms for leukocyte involvement in inflammatory joint disease.

Animals↗
PubMed1996

Endogenously produced urokinase amplifies tumor necrosis factor-alpha secretion by THP-1 mononuclear phagocytes.

This study examined the effects of endogenous urokinase (uPA) on lipopolysaccharide (LPS)-stimulated tumor necrosis factor alpha (TNF-alpha) secretion in THP-1 mononuclear phagocytes. Anti-uPA monoclonal antibody (mAb) suppressed LPS-driven TNF-alpha secretion by 61.6 +/- 5.9% (P<.001), and PAI-1, a uPA inhibitor, suppressed it to 53.1 +/- 8.2% of the control value (P<.001). Up-regulation of TNF-alpha mRNA was suppressed in parallel with secreted TNF-alpha protein. TNF-alpha secretion was unaffected by depleting plasminogen or by aprotinin, a plasmin inhibitor. When endogenous uPA was displaced from the cell, exogenous high-molecular-weight (intact) uPA augmented LPS-driven TNF-alpha secretion. By contrast, a uPA fragment containing the catalytic domain was inhibitory, and the uPA receptor-binding domain had no effect. We conclude that endogenous uPA amplifies TNF-alpha neosynthesis of LPS-stimulated THP-1 mononuclear phagocytes. The effect requires intact uPA and is independent of plasmin activity. This represents a novel mechanism by which a mononuclear phagocyte-derived protease contributes to generating proinflammatory signals.

Animals↗
PubMed1996

Glycated serum albumin induces chemokine gene expression in human retinal pigment epithelial cells.

Chronic hyperglycemia is thought to be important in the development of diabetic neovascularization but the mechanisms involved remain poorly understood. Interleukin-8 (IL-8) is a leukocyte chemokine and activating agent with angiogenic properties that is present in diabetic vitreous and may play a role in diabetic vasculopathy. We studied IL-8 and monocyte chemotactic protein-1 (MCP-1) production by human retinal pigment epithelial (hRPE) cells exposed to glycated human serum albumin (GHSA). Enzyme-linked immunoassay GHSA (500 micrograms/mL)-treated hRPE cells secreted levels of IL-8 and MCP-1 detectable within 4 h and reached 26.0 +/- 1.3 and 42.2 0.4 ng/10(6) cells/mL after 24 h, respectively. Induction of IL-8 and MCP-1 by GHSA at concentrations ranging from 62.5 to 3,000 micrograms/mL exhibited dose-dependent kinetics. The GHSA-induced chemokine secretion by hRPE was almost completely inhibited by actinomycin D and cycloheximide, suggesting that de novo mRNA and protein synthesis are necessary for the GHSA-induced IL-8 and MCP-1 production. Northern blot analysis of GHSA-induced hRPE IL-8 and MCP-1 mRNA expression corresponded to the time- and dose-dependent increases measured by enzyme-linked immunosorbent assay. High concentrations of glucose (20 mM; 360 mg/dl) increased GHSA-induced hRPE IL-8 and MCP-1 secretion, whereas added insulin (0.5 ng/mL) inhibited IL-8 but not MCP-1 protein secretion and mRNA expression. GHSA also induced hRPE to secrete GRO-alpha, RANTES, and NAP-2 chemokines. GHSA induction of hRPE chemokines further suggests a role for the hRPE in leukocyte infiltration, vascular injury, and neovascularization.

Cells, Cultured↗
PubMed1996

C-C chemokine-induced eosinophil chemotaxis during allergic airway inflammation.

The production of eosinophil-specific chemotactic factors during allergic airway responses may be a pivotal event resulting in eosinophil accumulation, activation, and airway damage. Recent studies have identified specific chemokines that may play crucial roles in recruitment of eosinophils to the site of allergic reactions. In this study we have utilized an established model of schistosome egg antigen (SEA) -mediated allergic responses to examine the role of specific C-C chemokines [macrophage inflammatory protein-1alpha (MIP-1alpha), RANTES, and monocyte chemoattractant protein-1 (MCP-1)] in eosinophil recruitment. We have previously identified a role for MIP-1alpha in eosinophil accumulation in the lung and airway during allergic airway inflammation. We extend those studies using in vitro eosinophil chemotaxis to establish that both MIP-1alpha and RANTES are potent eosinophil chemotactic factors in lungs during allergic airway responses. Morphometric analysis demonstrated a peribronchial accumulation of eosinophils within the lungs beginning at 8 h, peaking at 24 h, and plateauing at 48-96 h after allergen (SEA) challenge. Utilizing whole-lung homogenates from allergen-challenged mice, in vitro eosinophil chemotactic assays demonstrated significant increases in eosinophil chemotactic activity with 8-h lung homogenates and peak activity with samples from 24-h lung homogenates. These data correlated with the morphometric analysis of peribronchial eosinophil accumulation in situ. When lung homogenates from allergen-challenged mice were preincubated in vitro with antibodies specific for MIP-1alpha, RANTES, or MCP-1, a significant reduction in eosinophil chemotaxis was observed with only MIP-1alpha and RANTES neutralization. Altogether, these studies indicate that RANTES and MIP-1alpha are major eosinophil chemotactic factors produced during allergic airway responses.

Allergens↗
PubMed1996

Interleukin-7 (IL-7) induces retinal pigment epithelial cell MCP-1 and IL-8.

The neuroectodermally-derived retinal pigment epithelium (RPE) forms part of the blood-retina barrier where it is strategically-positioned to regulate leukocyte infiltration in retinal diseases. Activated human RPE cells possess several functions enabling them to perform this role including expression of HLA-DR antigens, production of intercellular adhesion molecule-1, and secretion of monocyte chemotactic protein-1 and interleukin-8. In this study, we examined the ability of interleukin-7 to induce RPE-derived monocyte chemotactic protein-1 and interleukin-8 and assessed the potentiating effects of interleukin-7 on interleukin-1 beta- and tumor necrosis factor-alpha-induced RPE monocyte chemotactic protein-1 and interleukin-8 production. Human RPE cells incubated with interleukin-7 (1-100 ng ml-1) for 24 hr secreted significant levels of antigenic RPE monocyte chemotactic protein-1 and interleukin-8 in a dose-dependent fashion interleukin-7 (P < 0.05). RPE costimulation with interleukin-7 and interleukin-1 beta (2 ng ml-1) or tumor necrosis factor-alpha (2 ng ml-1) resulted in additive increases (P < 0.05) in secreted monocyte chemotactic protein-1 and interleukin-8. Steady-state RPE monocyte chemotactic protein-1 mRNA was substantially increased by interleukin-7 (1-100 ng ml-1), while RPE interleukin-8 mRNA was mildly elevated by higher doses of interleukin-7 (10-100 ng ml-1). Time-dependent increases in RPE monocyte chemotactic protein-1 and interleukin-8 mRNA were noted. RPE monocyte chemotactic protein-1 mRNA peaked at 2 hr and decreased over 8 hr and 24 hr. Whereas, RPE interleukin-8 mRNA was perceptible at 2 hr, maximal at 8 hr, and reduced by 24 hr. Interleukin-7 potentiated interleukin-1 beta-induced monocyte chemotactic protein-1 and interleukin-8 steady-state mRNA expression at all interleukin-7 concentrations. Interleukin-7 potentiated tumor necrosis factor-alpha-induced RPE monocyte chemotactic protein-1 steady-state mRNA expression at all doses of interleukin-7 while only high dose interleukin-7 (100 ng ml-1) enhanced tumor necrosis factor-alpha-induced RPE interleukin-8 steady-state gene expression. Our data show that interleukin-7 is a primary stimulus of RPE monocyte chemotactic protein-1 and interleukin-8. This is one of the first reports demonstrating: (1) interleukin-7 induction of monocyte chemotactic protein-1 in any cell type, and (2) interleukin-7 induction of interleukin-8 in resident, tissue-based cells. These studies suggest that interleukin-7 potentiation of interleukin-1 beta and tumor necrosis factor-alpha-induced RPE monocyte chemotactic protein-1 and IL-8 may be important for the elicitation of leukocyte chemotaxins in diseased retinal tissue when only low ambient levels of individual pro-inflammatory cytokines are present.

Cells, Cultured↗
PubMed1996

Neutralization of macrophage inflammatory protein-2 attenuates neutrophil recruitment and bacterial clearance in murine Klebsiella pneumonia.

The role of macrophage inflammatory protein-2 (MIP-2) in bacterial pneumonia was characterized. Mice were challenged with Klebsiella pneumoniae intratracheally, and organs were harvested at 8, 24, and 48 h. Inoculation with K. pneumoniae resulted in the time-dependent expression of MIP-2 mRNA and protein within the lung, which was maximal 48 h after inoculation. Mice were then passively immunized with rabbit anti-murine MIP-2 serum intraperitoneally 2 h before administration of K. pneumoniae. Treatment with anti-MIP-2 serum resulted in a 60% decrease in lung neutrophil (PMNL) influx and a significant increase in K. pneumoniae colony-forming units in both lung and liver homogenates. Finally, treatment with anti-MIP-2 serum decreased early (48-72 h) but not late (after 72 h) survival in animals with Klebsiella pneumonia. This study indicates that MIP-2 is produced during Klebsiella pneumonia and inhibition of MIP-2 bioactivity in vivo results in decreased PMNL influx and lung bacterial clearance in murine Klebsiella pneumonia. MIP-2 is produced during Klebsiella pneumonia and inhibition of MIP-2 bioactivity in vivo results in decreased PMNL influx and lung bacterial clearance in murine Klebsiella pneumonia.

Animals↗
PubMed1996

Post-ischemic shunt following hepatic ischemia/reperfusion does not affect tissue chemokine levels of tissue injury.

Hepatic ischemia followed by reperfusion causes the release of a cascade of mediators, including tumor necrosis factor-alpha and epithelial neutrophil activating protein (ENA-78), which are important in the subsequent development of the lung and liver injury associated with this insult. We hypothesize that preferential post-ischemic shunting of blood into the nonischemic hepatic lobes at the time of reperfusion may increase the ischemic injury. To test this hypothesis, we utilized a rat model of lobar no-flow hepatic ischemia/reperfusion and removed the nonischemic hepatic lobes at the time of reperfusion to eliminate the preferential shunting of blood into the nonischemic tissues. We assessed pulmonary and hepatic tissue levels of ENA-78, pulmonary neutrophil influx and changes in pulmonary capillary permeability, and liver injury as measured by hepatic neutrophil influx and serum transaminase levels. Our results demonstrated that there were no significant differences in pulmonary and hepatic levels of ENA-78, or in the development of the lung and liver injury in animals undergoing resection of the nonischemic hepatic lobes at the time of reperfusion, as compared with animals undergoing hepatic ischemia/reperfusion alone.

Animals↗
PubMed1996

Hepatic inflammation following 70% hepatectomy may be related to up-regulation of epithelial neutrophil activating protein-78.

Tumor necrosis factor-alpha (TNF) is known to be released after partial hepatectomy. Furthermore, TNF triggers the release of chemotactic cytokines, such as epithelial neutrophil activating protein (ENA-78), which are important for neutrophil chemotaxis, activation, and propagation of the inflammatory response. We now postulate that ENA-78 may play a role the hepatic inflammatory response that occurs following partial hepatectomy. Rats were subjected to 70% hepatectomy or sham laparotomy and were killed in a time-dependent manner. Hepatic neutrophil influx, as assessed by myeloperoxidase (MPO) levels, serum alanine aminotransferase (ALT), and hepatic TNF and ENA-78 levels, as measured by ELISA, were evaluated at 1, 6, and 12 h following operation. MPO levels became significantly elevated within 6 h of hepatectomy and remained elevated at 12 h. Serum ALT became significantly elevated within 1 h of hepatectomy and continued to rise at 12 h. Hepatic TNF and ENA-78 were also increased significantly after hepatectomy. Next, rats undergoing 70% hepatectomy were treated with neutralizing anti-ENA-78 serum; this resulted in a significant decrease in hepatic MPO and serum ALT, suggesting less hepatic injury. To determine whether ENA-78 release was induced by TNF is this model, rats were treated with neutralizing anti-TNF serum and hepatic ENA-78 levels measured 6 h posthepatectomy. ENA-78 levels were significantly decreased in the animals receiving the anti-TNF serum, suggesting that ENA-78 is released in response to TNF in this model. These data suggest that TNF triggers the release of ENA-78 following 70% hepatectomy and that ENA-78 contributes to the hepatic neutrophil influx and liver injury following 70% hepatectomy.

Alanine Transaminase↗
PubMed1996

Recombinant human adenovirus with rat MIP-2 gene insertion causes prolonged PMN recruitment to the murine brain.

Single injections of recombinant cytokines/chemokines into tissue have provided insights into their possible roles during the inflammatory response. Adenoviral technology may allow us to mimic the in vivo situation more closely, with protein generated in a continuous but transient fashion. Replication-deficient human type 5 adenovirus containing a rat macrophage inflammatory protein-2 (MIP-2) gene insertion and cytomegalovirus promoter was injected into the mouse brain to investigate the inflammatory response to continuous overproduction of MIP-2. Adenovirus with a LacZ gene insertion expressing beta-galactosidase was used as a control. At doses of 10(4) to 10(7) plaque-forming units, a minimal inflammatory response was detected to the LacZ virus, with leukocyte recruitment that was restricted to the injection site. A dose of 10(7) plaque-forming units of both the LacZ and the MIP-2 vector produced extensive transgene product expression that persisted for at least 7 days. Astrocytes, recognized by their morphology, were the predominant cell type expressing MIP-2 and beta-galactosidase. A dose of 10(7) plaque-forming units of MIP-2 vector caused dramatic polymorphonuclear leukocyte (PMN) recruitment to the brain parenchyma after 2 days. PMN recruitment was still observed after 4 and 7 days, but had become more localized to the injection site and was associated with numerous foam-like macrophages. At both 2 and 7 days the blood-brain barrier was breached in the region of leukocyte recruitment. Despite the extent of leukocyte recruitment there were no overt signs of neuronal degeneration or demyelination. Our findings demonstrate that continuous production of MIP-2 in the CNS results in persistent PMN recruitment to the brain parenchyma with no evidence of tachyphylaxis. The lack of PMN recruitment to the brain parenchyma following CNS injury may be a result of deficient production of PMN chemoattractants.

Adenoviruses, Human↗
PubMed1996

Balance of inflammatory cytokines related to severity and mortality of murine sepsis.

We tested the hypothesis that, during sepsis, the balance of pro- and anti-inflammatory cytokines is related to severity and survival. Cecal ligation and puncture (CLP) with a large (18-gauge)-, intermediate (21-gauge)-, or small (26-gauge)-diameter needle, or sham laparotomy, was performed on outbred CD-1 mice. Concentrations of tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and the anti-inflammatory cytokine IL-10 were measured (by enzyme-linked immunosorbent assay) in serum, peritoneal lavage fluid, and liver and lung samples at 4, 8, 24, 48, and 96 h. As the diameter of the CLP needle decreased, the mortality rate decreased (at 48 h: large, 80%; intermediate, 40%; small, 20%; P < 0.05), the TNF-alpha and IL-6 concentrations decreased, and the time-to-peak TNF-alpha expression increased. In contrast, IL-10 concentration increased compared with baseline (serum at 24 h: large, 2.3-fold +/- 1.6-fold; intermediate, 2.0-fold +/- 0.5-fold; small, 49.9-fold +/- 8.3-fold; P < 0.05). Administration of IL-10 (5 microg, intraperitoneal) prior to CLP decreased mortality (P < 0.001). Administration of polyclonal anti-IL-10 serum prior to CLP (0.5 ml intraperitoneal) had the opposite effect and increased mortality (P < 0.001) and TNF-alpha, IL-6, and TNF-alpha mRNA expression compared with controls. Thus, severe sepsis is associated with a largely unopposed inflammatory response, and a largely unopposed inflammatory response (with anti-IL-10) results in severe sepsis and death. Less severe sepsis is associated with greater anti-inflammatory mediator expression, and greater anti-inflammatory mediator expression (with IL-10) results in less severe sepsis. Thus, the balance of inflammatory mediators is related to the severity and mortality of murine sepsis.

Animals↗
PubMed1996

Tumor necrosis factor mediates lung antibacterial host defense in murine Klebsiella pneumonia.

Tumor necrosis factor (TNF) is a proinflammatory cytokine which has recently been shown to have beneficial effects in the setting of acquired host immunity. However, the role of TNF in innate immune responses, as in the setting of bacterial pneumonia, has been incompletely characterized. To determine the role of TNF in gram-negative bacterial pneumonia, CBA/J mice were challenged with 10(2) CFU of Klebsiella pneumoniae intratracheally, resulting in the time-dependent expression of TNF MRNA and protein within the lung. Passive immunization of animals with a soluble TNF receptor-immunoglobulin (Ig) construct (sTNFR:Fc) intraperitoneally 2 h prior to K. pneumoniae inoculation resulted in a significant reduction in bronchoalveolar lavage neutrophils, but not macrophages, at 48 h, as compared with animals receiving control IgG1. Furthermore, treatment with sTNFR:Fc resulted in 19.6- and 13.5-fold increases in K. pneumoniae CFU in lung homogenates and plasma, respectively, as compared with animals receiving control IgG1. Finally, treatment of Klebsiella-infected mice with sTNFR:Fc markedly decreased both short- and long-term survival of these animals. In conclusion, our studies indicate that endogenous TNF is a critical component of antibacterial host defense in murine Klebsiella pneumonia.

Animals↗
PubMed1996

Endogenous modulators of TNF and IL-1 response are under partial control of TNF in baboon bacteremia.

Tumor necrosis factor (TNF) and interleukin (IL)-1 are two cytokines for which naturally occurring inhibitors have been identified. The present study was undertaken to evaluate the extent to which scavenging of TNF in bacteremia attenuates the plasma levels of IL-1 receptor antagonist (IL-1ra) and soluble TNF receptors (sTNFR). Ten male baboons received 2 x 10(9) colony-forming units/kg live Escherichia coli over 2 h and were subjected to either placebo or anti-TNF antibody (anti-TNF Ab) treatment (1 mg/kg CDP571, Celltech, UK) 2 h before E. coli infusion (observation time: 72h). IL-1ra (range: 50-100 ng/ml) and sTNFR (range: 55kDa, 20-25 ng/ml; 75 kDa, 30-35 ng/ml) release was more sustained than that of IL-1 and TNF and was significantly attenuated by anti-TNF treatment, as were the circulating levels of IL-1, IL-8, and monocyte chemotactic peptide-1 (MCP-1) in the anti-TNF Ab group. We conclude that the increase in circulating natural cytokine modulators observed in nonhuman primate bacteremia is under the partial control of endogenous TNF because it was influenced by anti-TNF pretreatment. This attenuation is comparable to the anti-TNF effect on the chemokine MCP-1.

Animals↗
PubMed1996

Airway hyperreactivity is associated with specific leukocyte subset infiltration in a mouse model of allergic airway inflammation.

Airway hyperreactivity is defined as an increased bronchoconstrictor response to physical, pharmacological, or other stimuli. Patients with asthma develop airway hyperreactivity as well as peribronchial inflammation. We employed an established schistosome soluble egg antigen (SEA)-induced murine model of allergic inflammation to examine the temporal relationship between airway hyperreactivity and leukocyte subset infiltration. Dose response curves of intravenous methacholine were used in mice to characterize airway reactivity at various time points after intranasal SEA rechallenge. Cellular infiltration into the airspace was assessed by bronchoalveolar lavage. Airway hyperreactivity increased as early as 1 h postchallenge. Peak hyperreactivity occurred at 8 h postchallenge. Subsequently, reactivity decreased at 24 h and fell to the level observed in controls by 48 h. Neutrophil influx correlated directly with the increase in airway reactivity, as neutrophils were observed as early as 1 h, peaked at 8 h, diminished by 24 h and were not detected at 48 h post-SEA challenge. In contrast, eosinophil infiltration was not observed until 24 h and peaked at 48 h post-SEA rechallenge when increases in airway reactivity were not detected. Airway resistance induced by methacholine correlated with neutrophil (r2 = 0.90) but not eosinophil (r2 = 0.1) infiltration. These results suggest that the airway hyperreactivity observed during allergic airway inflammation correlates with airways neutrophilia and weakly eosinophil accumulation.

Animals↗
PubMed1996

Inflammatory cytokines in patients with persistence of the acute respiratory distress syndrome.

To determine the relationship between airspace cytokines and cellular inflammatory responses in patients with the acute respiratory distress syndrome (ARDS), we performed bronchoalveolar lavage (BAL) in 82 prospectively identified, mechanically ventilated patients on Days 3, 7, 14, and/or 21 after the onset of ARDS. We studied the relationships between bronchoalveolar lavage fluid (BALF) cell populations and the concentrations of two potent neutrophil (PMN) chemoattractants, interleukin-8 (IL-8) and epithelial cell-derived neutrophil activator-78 (ENA-78); two potent monocyte chemoattractants, monocyte chemotactic peptide-1 (MCP-1) and macrophage inflammatory peptide-1 alpha (MIP-1 alpha); and the early response cytokine interleukin-1 beta (IL-1 beta) and its naturally occurring antagonist, IL-1 receptor antagonist protein (IRAP). We found that all of these cytokines were significantly increased regardless of the duration of ARDS. IL-8 and ENA-78 were the cytokines most strongly and consistently correlated with PMN concentrations in the lung fluids of patients with ARDS, and the correlations were independent of the other cytokines or coexisting lung infection. None of the cytokines tested correlated with macrophage concentrations. MCP-1 was directly correlated with lung injury score on Days 7, 14, and 21. Although neither IL-8 nor ENA-78 was associated with outcome, levels of IL-1 beta measured on Day 7 were associated with an increased risk of death (odds ratio [OR] = 2.8; 95% confidence interval [CI] = 1.1 to 7.4). These data demonstrate potential molecular mechanisms of the persistent inflammatory process in the lungs of patients with ARDS.

Adolescent↗
PubMed1996

Proinflammatory cytokines induce RANTES and MCP-1 synthesis in human corneal keratocytes but not in corneal epithelial cells. Beta-chemokine synthesis in corneal cells.

PURPOSE: To determine whether human corneal epithelial cells and keratocytes produce chemokines regulated upon activation, normal T-cell expressed and secreted (RANTES) protein and monocyte chemotactic protein-1 (MCP-1) after exposure to proinflammatory cytokines interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor-alpha (TNF-alpha). METHODS: Pure cultures of human corneal epithelial cells and keratocytes were exposed to increasing concentrations of either human recombinant IL-1 alpha or TNF-alpha. At selected time intervals after exposure, culture supernatants were removed and assayed for RANTES and MCP-1 by the enzyme-linked immunosorbent assay. Total RNA was extracted from the cell cultures, and steady state mRNA levels were measured by reverse transcriptase-polymerase chain reaction. RESULTS: Exposure to keratocytes to either IL-1 alpha or TNF-alpha resulted in > 100-fold increases in RANTES protein secretion and > 150-fold increases in MCP-1 protein secretion, as well as in rapid sustained increases in intracellular levels of their corresponding mRNAs. Exposure of corneal epithelial cells to IL-1 alpha and TNF-alpha did not stimulate MCP-1 secretion nor intracellular levels of MCP-1 mRNA. Epithelial cells also failed to secrete RANTES protein even through the two inducing cytokines did stimulate increased expression of RANTES mRNA. CONCLUSIONS: These results suggest that RANTES and MCP-1 gene expression in human keratocytes differs markedly from their expression in human corneal epithelial cells and that the stroma of the cornea may be more important than the epithelium in recruitment of mononuclear leukocytes responsible for cell-mediated immunity.

Adult↗