Biomedical subjects

J S Warren

Publications and source records attributed to J S Warren.

At least 55 records · Page 3Linked to original sources

PubMed1995

Regulatory roles of tumor necrosis factor-alpha and interleukin-1 beta in monocyte chemoattractant protein-1-mediated pulmonary granuloma formation in the rat.

Intravenous infusion of particulate yeast cell wall glucan into rats results in the synchronous development of angiocentric pulmonary granulomas that are composed almost entirely of monocytes and macrophages. Previous studies indicate that locally produced monocyte chemoattractant protein-1 (MCP-1) is required for full granuloma development. Because tumor necrosis factor-alpha (TNF-alpha) and interleukin 1 (IL-1) can induce MCP-1 production in a variety of cell types, we sought to determine their potential regulatory roles in this model. A single infusion of anti-TNF-alpha antibody at the time of glucan infusion (time 0) markedly reduced MCP-1 mRNA levels at 1 and 6 hours but not at later time points; there was no effect on granuloma size or number measured at 48 hours. When multiple infusions of anti-TNF-alpha antibody were administered over a 23-hour period (0 to 23 hours), MCP-1 mRNA was reduced through 24 hours, there was a significant reduction in peak bronchoalveolar lavage fluid MCP-1 activity at 48 hours, and there were marked reductions in granuloma size and number at 48 hours. Similar results were observed in animals that received infusions of anti-IL-1 beta. Infusion of anti-IL-1 beta at time 0 resulted in moderate reductions in MCP-1 mRNA at 1 and 6 hours and had no effect on granuloma size or number measured at 48 hours. When multiple infusions of anti-IL-1 beta were administered over a 23-hour period (0 to 23 hours), MCP-1 mRNA was reduced through 24 hours, there was a moderate reduction in peak bronchoalveolar lavage fluid MCP-1 activity at 48 hours, and there were marked reductions in granuloma size and number at 48 hours. A single infusion of anti-TNF-alpha and anti-IL-1 beta together at time 0 resulted in marked reductions in whole lung MCP-1 and mRNA at 1 and 6 hours, but not at 24 hours. Multiple combined infusions of anti-TNF-alpha and anti-IL-1 beta over a 23-hour period resulted in additive reductions in MCP-1 mRNA through 24 hours, bronchoalveolar lavage fluid MCP-1 activity at 48 hours, and granuloma size and number at 48 hours. These data suggest that locally produced TNF-alpha and IL-1 beta play regulatory roles in glucan-induced pulmonary granulomatous vasculitis through the modulation of local MCP-1 production.

Animals↗

PubMed1994

Lung monocyte chemoattractant protein-1 gene expression in bleomycin-induced pulmonary fibrosis.

Recent studies indicate that monocyte chemoattractant protein-1 (MCP-1) may play an important role in pulmonary inflammation. In vitro studies show that a number of cell types are capable of producing MCP-1. In this study, MCP-1 expression in lungs of rats with bleomycin (BLM)-induced pulmonary fibrosis is examined to evaluate its cellular origin and potential role in pathogenesis. Lung fibrosis was induced in male Fisher 344 rats by endotracheal injection on day 0. On selected days after injection, lungs were harvested for in situ and Northern hybridization analyses for MCP-1 mRNA expression, immunochemical and histochemical analyses for MCP-1 protein expression, and identification of cell type. Northern analysis revealed significant elevation in lung MCP-1 mRNA expression beginning on day 3 post-BLM treatment, increasing to a peak on day 7, and then decreasing toward control levels after day 21. In situ hybridization combined with histochemical staining with chromotrope 2R indicate that most of the cells expressing MCP-1 mRNA at these time points are primarily eosinophils. A few scattered reactive fibroblasts, some mononuclear cells, epithelial cells, and cells of certain blood vessel walls also express this mRNA. Increased MCP-1 protein expression also was found to be predominantly within and adjacent to eosinophils. The eosinophils expressing this mRNA were found predominantly within areas of active fibrosis. The kinetics of increase in the number of cells expressing significant MCP-1 mRNA in lung sections paralleled that for MCP-1 mRNA expression, as assessed by Northern analysis. These results, for the first time, demonstrate that MCP-1 is up-regulated significantly in this rat animal model, and that infiltrating eosinophils represent the major cellular source for this increased MCP-1 expression.

Animals↗

PubMed1994

Use of anti-neutrophil cytoplasmic antibody assay to distinguish between vasculitic disease activity and complications of cytotoxic therapy.

Anti-neutrophil cytoplasmic antibody (ANCA) determinations appear to be useful in the diagnostic evaluation and therapeutic monitoring of patients with necrotizing vasculitis. The purpose of this study was to determine whether semiquantitative ANCA measurements are useful in distinguishing between increases in primary disease activity and complications of cytotoxic or immunosuppressive therapy. The authors reviewed clinical data from 27 consecutive ANCA-positive patients who had at least three ANCA determinations performed at the University of Michigan Medical Center. Eleven patients had Wegener's granulomatosis (WG), 3 had "limited" WG; 9 had "ANCA-positive" vasculitis; and 4 had "pauciimmune" rapidly progressive glomerulonephritis. During a period of 3 months to 3.8 years, 159 ANCA determinations were performed, primarily for the purposes of diagnosis and monitoring disease activity. Eleven episodes were identified in which a single ANCA assay was used to distinguish between increased primary disease activity and a suspected therapeutic complication. The suspected therapeutic complications included pneumonia (8 of 11), bacterial sinusitis (1 of 11), cyclophosphamide-induced pneumonitis (1 of 11), and cyclophosphamide-induced vestibular toxicity (1 of 11). In 10 of 11 instances in which an ANCA assay was used to distinguish between an exacerbation in vasculitic disease activity and a therapeutic complication, interpretation of the ANCA titer was pivotal in arriving at a therapeutically appropriate decision either to increase or discontinue cytotoxic therapy. This study suggests that ANCA determinations can be used reliably to distinguish between increased primary disease activity and complications of therapy that mimic an increase in disease activity.

Adolescent↗

PubMed1994

Lipopolysaccharide induces monocyte chemoattractant protein production by rat mesangial cells.

Lipopolysaccharide, a potent pro-inflammatory constituent of bacterial cell walls, is capable of promoting glomerular inflammation, by both activating circulating inflammatory cells and local interactions with renal parenchymal cells. We sought to determine whether lipopolysaccharide was capable of promoting glomerular inflammation by directly stimulating mesangial cell production of monocyte chemoattractant protein 1, a recently described cytokine capable of eliciting recruitment of mononuclear phagocytes into inflammatory foci. Northern hybridization analysis revealed dose and time-dependent induction of mRNA coding for monocyte chemoattractant protein 1 in quiescent rat mesangial cells treated with lipopolysaccharide. Lipopolysaccharide-elicited induction of monocyte chemoattractant protein mRNA was detectable after 1 hour and persisted for at least 30 hours. Media isolated from rat mesangial cell cultures stimulated by lipopolysaccharide possessed monocyte chemotactic activity that was detectable at 8 hours and peaked at 24 hours; an antimonocyte chemoattractant protein antibody blocked 87% of this chemotactic activity. We suggest that lipopolysaccharide, released from bacterial cell walls, promotes glomerular inflammation by stimulating mesangial cell production of monocyte chemoattractant protein 1.

Animals↗

PubMed1993

Tumor necrosis factor, interleukin 6, and the acute phase response following hepatic ischemia/reperfusion.

We report here the production of systemic levels of tumor necrosis factor (TNF) and interleukin 6 (IL-6) and associated changes in serum macroglobulin to albumin ratios in a nonlethal rat model of partial hepatic ischemia/reperfusion (I/R). Plasma IL-6 was detectable and elevated at 1 hr of reperfusion as compared to sham-operated controls (I/R rats = 12,100 +/- 3860 pg/ml; sham rats = 5260 +/- 842 pg/ml; IL-6 values = means +/- SEM) and reached maximal levels at 6 hr of reperfusion (I/R rats = 47,400 +/- 25,700 pg/ml; sham rats = 3370 +/- 394 pg/ml), in contrast to maximal TNF levels at 30 min of reperfusion (I/R rats = 72 +/- 15 pg/ml; sham rats = 2 +/- 2 pg/ml; TNF values = means +/- SEM). Pretreatment with neutralizing TNF antisera prior to ischemia resulted in a reduction of IL-6 at 1 hr of reperfusion (anti-TNF = 3870 +/- 2550 pg/ml; control serum = 7650 +/- 1670 pg/ml), but was without effect on IL-6 levels at subsequent time points over the 24 hr of reperfusion. Electrophoretic determination of macroglobulin (alpha 1 + alpha 2) and albumin concentrations in sham-operated and ischemia/reperfusion animals demonstrated an elevation in the macroglobulin/albumin ratio in both groups over time, suggestive of an acute phase response, and the ratio was unchanged by immunoneutralization of TNF prior to ischemia/reperfusion. We conclude that this model of hepatic ischemia/reperfusion results in temporally distinct systemic elevations in IL-6 and TNF; however, the induction of IL-6 and the associated changes in serum macroglobulin concentration are independent of TNF.

Animals↗

PubMed1993

Complement component C5 modulates the systemic tumor necrosis factor response in murine endotoxic shock.

Patients with disseminated Neisseria meningitidis infections (meningococcemia) suffer from a fulminant shock syndrome that is accompanied by extraordinarily high concentrations in serum of tumor necrosis factor (TNF). People with homozygous deficiencies of late complement components (C5, C6, C7, and C8) experience a high incidence of disseminated neisserial infections yet suffer from an attenuated form of the disease. The mechanisms that account for this disparity in host response are unclear, but they may in part be related to differences in the systemic TNF response that are modulated by terminal complement components (C5 to C9). The role of C5 in the modulation of the systemic endotoxin-induced TNF response was studied with matched strains of C5-deficient (B10 D2/Osn) and complement-sufficient (B10 D2/Nsn) mice. Following lipopolysaccharide (LPS) administration, complement-sufficient mice exhibited more rapid increases in pulmonary and hepatic vascular permeabilities than did C5-deficient controls. Complement-sufficient mice developed acute passive hepatic congestion, they appeared more ill than C5-deficient mice, and they exhibited a twofold greater rise in serum TNF activity compared with that by C5-deficient mice. C5-deficient mice reconstituted with normal serum before an LPS injection exhibited pulmonary and hepatic vascular permeability increases and serum TNF levels approaching those observed in complement-sufficient mice. Alveolar and peritoneal macrophages isolated from complement-sufficient and C5-deficient mice and incubated in heat-inactivated serum did not exhibit differences in TNF mRNA expression or secreted TNF activity following stimulation with LPS. However, incubation of macrophages in complement-sufficient mouse serum (before LPS stimulation) resulted in increased TNF mRNA expression and TNF activity compared with those in cells incubated in C5-deficient serum. In vitro studies employing human complement components and peripheral blood monocytes revealed that recombinant C5a, in the presence or absence of LPS, can induce increased concentrations of TNF and that C5b to C9 had no additional modulatory effect on the TNF response. These data suggest that C5 modulates the endotoxin-triggered TNF response. The role of complement components distal to C5 (i.e., C5b to C9) in the endotoxin-triggered TNF response remains unclear.

Animals↗

PubMed1993

Expression of monocyte chemoattractant protein-1 (MCP-1) by rat alveolar macrophages during chronic lung injury.

Using a well-characterized model of bleomycin-induced pulmonary fibrosis in the rat, we determined that there was a time-dependent elaboration of monocyte chemotactic activity in bronchoalveolar lavage fluid. Northern hybridization analysis revealed markedly increased expression of rat monocyte chemoattractant protein-1 (MCP-1) mRNA in alveolar macrophages (AMs) from rats following induction of pulmonary fibrosis. Monocyte chemotactic activity was also significantly increased in conditioned media from AMs retrieved from injured rat lungs. These data suggest that one important role of AMs in the pathogenesis of chronic inflammatory lung injury and pulmonary fibrosis is the regulation of monocyte recruitment and activation within the lung secondary to secretion of monocyte chemoattractants including MCP-1.

Animals↗

PubMed1993

Requirements for tumor necrosis factor-alpha and interleukin-1 in limb ischemia/reperfusion injury and associated lung injury.

Ischemia in rat hind limbs followed by reperfusion results in local as well as remote organ (lung) injury characterized by increased vascular permeability (125I-labeled bovine serum albumin leakage) and hemorrhage (51Cr-labeled rat erythrocytes extravasation) in skeletal muscle and lung, together with an associated increased tissue content of myeloperoxidase, reflecting neutrophil accumulation. Within 60 minutes of reperfusion following ischemia, tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), and IL-6 plasma levels increased significantly, reaching maximum levels after 2 hours of reperfusion. Polyclonal antibodies to TNF-alpha and IL-1 provided significant protection against vascular injury in both muscle and lung. These results were confirmed by the use of soluble TNF-alpha receptor and IL-1 receptor antagonist. In rat lungs following ischemia and reperfusion, there was immunohistochemical evidence of E-selectin expression in the lung vasculature; this expression was blocked by treatment of animals with anti-TNF-alpha. These data indicate that both local (hind limb) and remote (lung) organ injury after ischemia/reperfusion requires participation of TNF-alpha and IL-1. The cytokines may, in part, be involved in the up-regulation of endothelial adhesion molecules.

Animals↗

PubMed1993

Analysis of monocyte chemoattractant protein 1-mediated lung injury using rat lung organ cultures.

Using a rat lung organ culture system, we analyzed the role of monocyte chemoattractant protein 1 (MCP 1) in leukocyte to lung adhesive interactions and monocyte-mediated lung injury. Quantitative leukocyte to lung adhesive interactions were examined using an adaptation of the Woodruff-Stamper frozen section binding assay. Pretreatment of organ cultures with recombinant human tumor necrosis factor (rhTNF alpha) resulted in a protein synthesis-dependent increase in the adhesiveness of lung tissue for peripheral blood monocytes. Adhesion of monocytes to lung tissue was not increased above baseline after 7 hours but increased more than twofold by 24 hours and persisted through 48 hours. Binding of monocyte to lung tissue was further increased when recombinant rat MCP 1 was added to monocyte suspensions immediately before being layered onto lung sections derived from either TNF alpha-treated or untreated organ cultures. Addition of antibody directed against rat CD11b/c resulted in a moderate reduction in monocyte binding. TNF or lipopolysaccharide-induced activation of mononuclear cells in the presence of [3H]leucine-labeled organ cultures resulted in lung injury as assessed by radioisotope release. Mononuclear cell-mediated organ culture injury could be partially inhibited with anti-rat MCP 1 antibody, anti-rat CD11b/c antibody, or antioxidants including catalase and deferoxamine. Anti-MCP 1 and anti-CD11b/c increased the absolute numbers of monocytes that could be retrieved from monocyte-lung co-cultures while catalase and deferoxamine did not. In vitro studies revealed that isolated rat peripheral blood monocytes produce O2- in response to MCP 1. These data provide a functional correlate for recent in vitro studies which suggest that MCP 1 may mediate leukocyte adhesive processes by up-regulating beta 2 integrin expression on monocytes. This study provides evidence that monocytes activated by MCP 1 can damage lung tissue through an oxidant-mediated mechanism. Monocyte chemoattractant protein 1 may participate in the pathogenesis of monocyte-mediated lung injury by modulating inflammatory cell adhesion as well as through monocyte activation.

Animals↗

PubMed1993

Pulmonary granuloma formation in the rat is partially dependent on monocyte chemoattractant protein 1.

BACKGROUND: We have examined the role of MCP-1 (monocyte chemoattractant protein 1; also known as monocyte chemotactic and activating factor or the murine JE gene product) in the pathogenesis of glucan-induced granulomatous vasculitis in the rat. While in vitro studies indicate that MCP-1 possesses monocyte chemotactic and activating activities, little is known about its biologic role in pathologic processes. Glucan-induced pulmonary granulomatous vasculitis is an ideal model in which to study the role of MCP-1, because the granulomas develop rapidly and synchronously and are monocyte/macrophage-rich. EXPERIMENTAL DESIGN: The purpose of this study was to define the topographic distribution and temporal pattern of MCP-1 expression in the lungs of rats with evolving glucan-induced granulomatous vasculitis and to determine the effect of neutralization of MCP-1 activity on granuloma formation. Glucan-induced pulmonary granulomatous vasculitis was induced in rats by the intravenous infusion of yeast cell wall glucan. At the indicated time points after glucan infusion, rats were sacrificed and the lungs processed for Northern, immunohistochemical and in situ hybridization analyses of MCP-1 production. Morphometric analysis was used to quantify the effect of neutralization of MCP-1 activity on granuloma formation. RESULTS: Granuloma formation was accompanied by a biphasic increase in steady-state whole lung MCP-1 mRNA levels that peaked at 1 and 6 to 24 hours. In situ hybridization and immunohistochemical analyses revealed that components of the bronchial and vascular walls are responsible for the early rise (1 hour) in MCP-1 mRNA and protein expression, whereas granuloma-associated alveolar macrophages are the predominant source of MCP-1 later (6 to 24 hours) in the evolution of these lesions. Intravenous infusion and/or intratracheal instillation of neutralizing concentrations of anti-rat MCP-1 antibody raised against recombinant rat MCP-1 resulted in a dramatic decrease in the number and size of glucan-induced granulomas as well as in the numbers of mononuclear phagocytes retrieved in bronchoalveolar lavage fluid. CONCLUSIONS: These studies demonstrate that glucan-induced granulomatous vasculitis is accompanied by increased local expression of MCP-1 mRNA and protein, that there is a coordinated production of MCP-1 by different cell types within the lung during evolving glucan-induced pulmonary vasculitis, and that MCP-1 plays a requisite role in pulmonary granuloma formation.

Animals↗

PubMed1992

Potential role of monocyte chemoattractant protein 1/JE in monocyte/macrophage-dependent IgA immune complex alveolitis in the rat.

We have examined the role of monocyte chemoattractant protein 1 (MCP 1) in the pathogenesis of monocyte/macrophage-dependent IgA immune complex alveolitis in the rat. Rat MCP 1 was cloned and expressed in order to facilitate analysis of its function in rat models of human disease. A cDNA library was constructed from rat pulmonary artery endothelial cells stimulated with TNF-alpha. The cDNA library was screened with synthetic oligonucleotide probes based on the recently published rat MCP 1 cDNA sequence. Among numerous MCP 1-positive clones, four full length (approximately 480 bp) cDNA were rescued, amplified by polymerase chain reaction, and ligated into a pJVETLZ baculovirus transfer vector. Spodoptera frugiperda insect cells (Sf-21) infected with baculovirus recombinants (Auto-grapha california nuclear polyhedrosis virus) bearing properly oriented MCP 1 cDNA (AcMCP 1) directed the expression of unique peptides of 18, 21, and 23 kDa. Treatment of AcMCP 1-infected Sf-21 cells with tunicamycin resulted in reduced production of the 21- and 23-kDa proteins and an increase in 16- to 18-kDa products, the predicted size range of uncleaved and nonglycosylated rat MCP 1. Denatured and refolded 23-kDa and 21-kDa rat MCP 1 species exhibited dose-dependent monocyte-specific chemotactic activity at concentrations as low as 10(-10) M whereas the 18-kDa species exhibited negligible activity. Antibodies that react with the immunoblot, block rat rMCP 1-directed monocyte chemotaxis, and neutralize monocyte-specific chemotactic activity secreted by TNF-stimulated rat endothelial cells were raised in rabbits immunized with the 23-kDa MCP 1 species. Intravenous administration of anti-MCP 1 antibodies upon initiation of IgA immune complex lung injury resulted in a marked reduction in lung injury as measured by pulmonary vascular permeability, alveolar hemorrhage, and pulmonary monocyte/macrophage recruitment and pulmonary monocyte/macrophage recruitment. These data suggest that MCP 1 may play an important role in the pathogenesis of monocyte/macrophage-dependent IgA immune complex alveolitis in the rat.

Animals↗

PubMed1992

Lung injury after deposition of IgA immune complexes. Requirements for CD18 and L-arginine.

Acute lung injury produced by deposition of IgA immune complexes is complement-dependent, neutrophil-independent, oxygen radical-mediated, and may be a result of the formation of the hydroxyl radical (HO) generated directly or indirectly from activated lung macrophages. The current studies were designed to evaluate further the pathophysiologic events that occur after intrapulmonary deposition of IgA immune complexes. Pretreatment of rats with the human recombinant soluble complement receptor-1 resulted in marked attenuation of IgA immune complex-induced lung injury. Intravenous administration of antibody to CD18, but not antibody to CD11b, was highly protective against lung injury. Treatment of animals with either anti-endothelial leukocyte-adhesion molecule-1 or anti-TNF-alpha, both of which were highly protective against IgG immune complex-induced lung injury, had no protective effects in the model of IgA immune complex-induced lung injury. Immunohistochemical analysis revealed up-regulation of the endothelial leukocyte adhesion molecule-1 in the pulmonary vasculature after deposition of IgA immune complexes. This up-regulation was TNF-alpha-dependent. The arginine analog, NG-monomethyl-L-arginine, was highly protective against IgA immune complex-induced lung injury. This protective effect was reversed by the co-presence of L-arginine (but not D-arginine). Protective interventions against IgA immune complex-induced lung injury were inversely correlated with the numbers of macrophages that could be retrieved by lung lavage. These data suggest fundamental differences in the pathogenesis of lung injury after intrapulmonary deposition of IgA immune complexes, as compared with injury caused by deposition of IgG immune complexes. In the latter, neutrophils, intrapulmonary generation of TNF-alpha, and up-regulation of pulmonary vascular endothelial leukocyte-adhesion molecule-1 are required for the full development of lung injury, whereas no such requirements appear in the case of IgA immune complex-induced lung injury. Full expression of IgA immune complex-induced lung injury also appears to require L-arginine, suggesting a possible role for nitric oxide or its derivatives in events ultimately leading to injury.

Animals↗

PubMed1992

Biphasic production of IL-8 in lipopolysaccharide (LPS)-stimulated human whole blood. Separation of LPS- and cytokine-stimulated components using anti-tumor necrosis factor and anti-IL-1 antibodies.

TNF, IL-1, and IL-6 are integral components of the cytokine cascade released in the response to inflammatory stimuli such as LPS. IL-8 is produced both in response to LPS as well as TNF and IL-1. The early, local production of TNF and IL-1 may therefore contribute to the subsequent expression of IL-8. This hypothesis was tested using LPS-stimulated human whole blood as an ex vivo model of local cytokine production. The production of TNF, IL-1 alpha, IL-1 beta, IL-6, and IL-8 was found to be responsive to a wide range of LPS concentrations (0.1 ng/ml-10 micrograms/ml). These cytokines were first detected between 1 to 4 h post-LPS stimulation, and reached plateau levels after 6 to 12 h. IL-8, however, also displayed a secondary wave of production, with the levels again increasing between 12 to 24 h. The IL-8 present in the plasma after LPS stimulation was biologically active, as assessed by neutrophil chemotaxis. In further studies, addition of anti-TNF and anti-IL-1 neutralizing antibodies, alone and in combination, to LPS-stimulated blood resulted in nearly complete ablation of the secondary phase of IL-8 synthesis at both the levels of protein and mRNA, while leaving the first, LPS-mediated phase of IL-8 synthesis unaffected. This model of cytokine production in human whole blood may reflect the sequence of events in a localized environment of inflammation where both a primary stimulus and the induced early cytokine mediators may serve to elicit multiple, temporally distinct phases of IL-8 production.

Antibodies, Monoclonal↗

PubMed1992

Roles of beta 2 integrins of rat neutrophils in complement- and oxygen radical-mediated acute inflammatory injury.

The roles of beta 2 integrin molecules in neutrophil accumulation and tissue injury have been examined by the use of antibodies that are reactive with human CD11b and CD18 and cross-react with the homologous epitopes on rat neutrophils. Adherence to rat pulmonary artery endothelial cells by human neutrophils and endothelial cell killing by phorbol ester-activated human neutrophils required CD11b, CD11c, and CD18. Companion adherence studies between rat neutrophils and endothelial cells revealed a requirement for both CD11b and CD18. Neither anti-CD11b nor anti-CD18 depressed in vitro responses (O2- generation and chemotactic migration) of rat neutrophils. The accumulation of neutrophils in glycogen-induced peritoneal exudates was diminished substantially in rats treated with either anti-CD18 or anti-CD11b. In oxidant-mediated acute lung injury induced by rapid intravascular infusion of cobra venom factor, treatment of rats with either anti-CD18 or anti-CD11b significantly attenuated injury as assessed by increases in vascular permeability and hemorrhage. These protective effects correlated morphologically with diminished adhesion of neutrophils to interstitial intrapulmonary capillary endothelial cells. In studies of immune complex (BSA-anti-BSA)-induced alveolitis and dermal vasculitis, anti-CD18 had protective effects at all doses of anti-BSA employed. The protective effects of anti-CD18 correlated with diminished neutrophil accumulation in tissues at lower doses of anti-BSA. Although anti-CD11b was not effective under the same experimental conditions, intratracheal administration of this antibody conveyed protection against immune complex-induced lung injury, suggesting that both CD11b and CD18 are required for the full expression of injury. The current studies also demonstrated that when surface-bound IgG immune complexes were treated with fresh rat serum, the increment in O2- and TNF alpha generated by alveolar macrophages was suppressed by anti-CD18, but not by anti-CD11b, suggesting a heretofore unrecognized role for CD18 in the O2- and TNF-alpha responses of alveolar macrophages. Thus, neutrophil beta 2 integrins play a requisite role for the full expression of complement-dependent and oxygen radical-mediated injury of the lung and dermal vasculature.

Animals↗

PubMed1992

Effect of acute inflammatory lung injury on the expression of monocyte chemoattractant protein-1 (MCP-1) in rat pulmonary alveolar macrophages.

Using a well-characterized rat model of immune complex-mediated acute inflammatory lung injury, we determined that there is a time-dependent elaboration of monocyte chemotactic activity in bronchoalveolar lavage fluid. Monocyte chemotactic activity is also significantly enhanced in culture supernatants from pulmonary alveolar macrophages (PAMs) from injured rat lungs. Northern hybridization analysis revealed markedly increased expression of rat monocyte chemoattractant protein 1 (MCP-1) mRNA in PAMs obtained from rats with immune complex-induced lung injury. The increased expression of MCP-1 mRNA and associated increase in monocyte chemotactic activity present in culture supernatants of PAMs from injured rat lungs suggest that PAMs may participate in the pathogenesis of acute inflammatory lung injury by the secretion of monocyte chemoattractants including MCP-1.

Animals↗

PubMed1992

Relationship between interleukin-1 beta and platelet-activating factor in the pathogenesis of acute immune complex alveolitis in the rat.

Intrapulmonary interleukin-1 beta (IL-1 beta) participates in the pathogenesis of acute IgG immune-complex alveolitis through a mechanism involving neutrophil recruitment. We have examined the relationship between intrapulmonary IL-1 beta and locally produced platelet-activating factor (PAF) in the development of acute alveolitis. Instillation of IgG anti-bovine albumin into the lungs of rats, followed immediately by intravenous infusion of bovine serum albumin (BSA), resulted in acute neutrophil-mediated lung injury. Development of IgG immune-complex lung injury was accompanied by three- and five-fold increases in bronchoalveolar lavage (BAL) fluid and whole lung PAF levels, respectively. Intratracheal administration of the PAF antagonists, WEB-2086 (Boehringer) or L-652,731 (Merck, Sharpe, and Dohme, Rahway, NJ), reduced pulmonary vascular leakage. Neutralization of intrapulmonary IL-1 activity with anti-IL-1 beta antibodies reduced pulmonary vascular permeability and whole lung PAF levels. Morphometric analysis and whole lung myeloperoxidase measurements revealed a differential effect between the PAF antagonists and anti-IL-1 beta with respect to pulmonary neutrophil recruitment. Intratracheal instillation of anti-IL-1 beta retarded net pulmonary neutrophil recruitment while the PAF antagonists retarded migration of neutrophils from the interstitial/vascular compartments into the alveolar compartment. Intratracheal instillation of anti-IL-1 beta plus L-652,731 resulted in reduction in lung vascular permeability and retarded net pulmonary neutrophil recruitment. No additive effect was observed. Stimulation of isolated mouse alveolar macrophages with recombinant murine IL-1 beta or IL-1 alpha resulted in rapid, dose-dependent, and cell concentration-dependent increases in PAF secretion. These data suggest that intrapulmonary IL-1 beta amplifies local PAF production and that IL-1 beta and PAF modulate different aspects of pulmonary neutrophil recruitment.

Acute Disease↗

PubMed1992

Monocyte chemoattractant protein 1 in a rat model of pulmonary granulomatosis.

Monocyte chemoattractant protein 1 (MCP1), also known as monocyte chemotactic and activating factor, possesses potent chemotactic activity for monocytes and can augment monocyte tumoristatic activity against some tumor cell lines. While these activities suggest a role in inflammatory and immunologic processes, the biologic role of MCP1 has not been studied in vivo. Glucan-induced pulmonary granulomatosis in the rat is an ideal model in which to study the role of MCP1 because the granulomas are monocyte/macrophage rich. Intravenous infusion of particulate yeast cell wall glucan resulted in the synchronous development of angiocentric pulmonary granulomas. Early lesions (6 hours) were characterized by intravascular glucan aggregates surrounded by neutrophils and foci of alveolar hemorrhage while later appearing granulomatous lesions (48 to 96 hours) were dominated by monocytes and macrophages. Granuloma formation was paralleled by a peripheral blood monocytosis. Analysis of bronchoalveolar lavage (BAL) fluid revealed an early, transient rise in tumor necrosis factor activity followed by a marked rise in monocyte-specific chemotactic activity. The rise in BAL fluid monocyte chemotactic activity, which coincided with the development of the monocyte/macrophage-rich granulomas, was preceded by a marked increase in whole lung MCP1 mRNA expression. BAL fluid monocyte chemotactic activity could be nearly completely neutralized with antibody directed against rat MCP1. These studies demonstrate that MCP1 mRNA expression is upregulated in glucan-induced pulmonary granulomatosis and that MCP1 is present in BAL fluid. Intrapulmonary granulomatosis may be important in the pathogenesis of granuloma formation.

Animals↗

PubMed1991

Intrapulmonary interleukin 1 mediates acute immune complex alveolitis in the rat.

Interleukin 1 alpha and beta are polypeptide cytokines that possesses a wide variety of immunologic and inflammatory activities. We have examined the role of intrapulmonary interleukin 1 in the pathogenesis of acute IgG immune complex alveolitis in the rat. Intratracheal instillation of IgG anti-bovine serum albumin accompanied by intravenous infusion of bovine albumin results in acute neutrophil and complement-dependent alveolitis. Over the course of evolving lung injury there was a 12-fold increase in bronchoalveolar lavage fluid interleukin 1 activity. Intratracheal instillation of neutralizing anti-interleukin 1 beta antibodies upon induction of lung injury resulted in a dose-dependent reduction in lung injury as assessed by measurements of pulmonary hemorrhage and vascular permeability. Morphometric analysis and measurements of myeloperoxidase activities in whole lung homogenates from rats that received anti-interleukin 1 beta revealed a pronounced reduction in neutrophil recruitment compared to positive controls. Incubation of isolated alveolar macrophages with preformed IgG immune complexes resulted in dose-dependent interleukin 1 secretion. These data suggest that intrapulmonary IL-1 activity plays a role in neutrophil recruitment and is necessary for the full development of acute IgG immune complex induced lung injury in the rat.

Acute Disease↗