Chemokine and inflammatory cytokine changes during chronic wound healing

Wound healing is a complex process resulting from an interplay of processes including coagulation, inflammation, angiogenesis, and epithelialization. The chemokine family has been shown to contain members that are potent regulators of many of these pathways. Because we have previously shown that chemokines "pool" in biologic wound dressings, we studied the levels of CXC and CC chemokines, along with key inflammatory mediators, serially from a group of patients undergoing therapy for chronic venous leg ulcers. After 8 weeks, all patients had marked clinical healing of their ulcers (median 63.3% reduction in size) with two of 10 completely healed. Wound fluids extracted from dressings showed high levels of platelet factor-4 and interferon-gamma-inducible protein, with a trend toward increases in the ratio of the sums of the angiogenic versus angiostatic CXC chemokines (p = 0.082) in the tissues collected from the center of the ulcers during wound closure. Neutrophil-activating peptide-2 and interleukin-8 accounted for the most changes in wound fluid angiogenic chemokines, with significant differences both as compared with baseline levels and with patients' plasma level noted at various time points between weeks 0 and 8. The level of angiostatic chemokines, interferon-y inducible protein 10 and platelet-activating-4, fell most significantly between weeks 0 and 3 as compared with plasma levels. The observed shift toward angiogenic CXC chemokines suggests that effective healing in chronic venous insufficiency ulcers appears to "move" the ulcer bed toward a state more conducive to epithelialization,characteristic of the proliferative phase of wound healing. CC chemokines were also elevated at baseline in the wound fluid samples as compared with the patients' plasma levels. Macrophage inflammatory protein-1 (3 and regulated on activation, normal T expressed and secreted (RANTES) levels decreased with healing, whereas there were significant increases in the tissue levels of monocyte chemoattractant protein-1 and macrophage inflammatory protein-1 a over the first 4 weeks of therapy (p< or = 0.05 for both). Coincident with these changes was a steady increase in the ratio of interleukin-1 R/interleukin-1 receptor antagonist protein in the ulcer center tissues, which also correlated with healing (p < 0 .05) as compared with a decreasing ratio at the ulcer edge, and a biphasic response in the wound fluids. These findings suggest that advanced wound care techniques help move the ulcer from a chronic inflammatory state into one more characteristic of the late inflammatory/early proliferative phase of wound healing. Chemokines may play a critical role in the pathogenesis of chronic venous ulcers through their effects on angiogenesis and/or the progression of inflammatory reactions at the site of injury.

Automation bias: decision making and performance in high-tech cockpits

Automated aids and decision support tools are rapidly becoming indispensable tools in high-technology cockpits and are assuming increasing control of"cognitive" flight tasks, such as calculating fuel-efficient routes, navigating, or detecting and diagnosing system malfunctions and abnormalities. This study was designed to investigate automation bias, a recently documented factor in the use of automated aids and decision support systems. The term refers to omission and commission errors resulting from the use of automated cues as a heuristic replacement for vigilant information seeking and processing. Glass-cockpit pilots flew flight scenarios involving automation events or opportunities for automation-related omission and commission errors. Although experimentally manipulated accountability demands did not significantly impact performance, post hoc analyses revealed that those pilots who reported an internalized perception of "accountability" for their performance and strategies of interaction with the automation were significantly more likely to double-check automated functioning against other cues and less likely to commit errors than those who did not share this perception. Pilots were also lilkely to erroneously "remember" the presence of expected cues when describing their decision-making processes.

Automation bias and errors: are crews better than individuals?

The availability of automated decision aids can sometimes feed into the general human tendency to travel the road of least cognitive effort. Is this tendency toward "automation bias" (the use of automation as a heuristic replacement for vigilant information seeking and processing) ameliorated when more than one decision maker is monitoring system events? This study examined automation bias in two-person crews versus solo performers under varying instruction conditions. Training that focused on automation bias and associated errors successfully reduced commission, but not omission, errors. Teams and solo performers were equally likely to fail to respond to system irregularities or events when automated devices failed to indicate them, and to incorrectly follow automated directives when the contradicted other system information.

Secondary lymphoid tissue chemokine mediates T cell-dependent antitumor responses in vivo

Secondary lymphoid tissue chemokine (SLC, also referred to as Exodus 2 or 6Ckine) is a recently identified high endothelial-derived CC chemokine. The ability of SLC to chemoattract both Th1 lymphocytes and dendritic cells formed the rationale to evaluate this chemokine in cancer immunotherapy. Intratumoral injection of recombinant SLC evidenced potent antitumor responses and led to complete tumor eradication in 40% of treated mice. SLC-mediated antitumor responses were lymphocyte dependent as evidenced by the fact that this therapy did not alter tumor growth in SCID mice. Studies performed in CD4 and CD8 knockout mice also revealed a requirement for both CD4 and CD8 lymphocyte subsets for SLC-mediated tumor regression. In immunocompetent mice, intratumoral SLC injection led to a significant increase in CD4 and CD8 T lymphocytes and dendritic cells, infiltrating both the tumor and the draining lymph nodes. These cell infiltrates were accompanied by the enhanced elaboration of Th1 cytokines and chemokines monokine induced by IFN-gamma and IFN-gamma-inducible protein 10 but a concomitant decrease in immunosuppressive cytokines at the tumor site. In response to irradiated autologous tumor, splenic and lymph node-derived cells from SLC-treated tumor-bearing mice secreted significantly more IFN-gamma, GM-CSF, and IL-12 and reduced levels of IL-10 than did diluent-treated tumor-bearing mice. After stimulation with irradiated autologous tumor, lymph node-derived lymphocytes from SLC-treated tumor-bearing mice demonstrated enhanced cytolytic capacity, suggesting the generation of systemic immune responses. These findings provide a strong rationale for further evaluation of SLC in tumor immunity and its use in cancer immunotherapy.

Neutrophil recruitment and resistance to urinary tract infection

This study examined the role of neutrophil leukocytes for the antibacterial defense at mucosal infection sites. Urinary tract infection (UTI) was established by injection into the bladder lumen of Escherichia coli 1177, a fully virulent clinical isolate. Infection of C3H/HeN (lpsn, lpsn) mice recruited neutrophils into the urinary tract, and bacteria were cleared from kidneys and bladders. The neutrophil response was absent in C3H/HeJ (lpsd, lpsd) mice, and bacteria persisted in the tissues. Peripheral neutrophil depletion of C3H/HeN mice was subsequently achieved by pretreatment with the granulocyte-specific antibody RB6-8C5. The E. coli-induced neutrophil recruitment was inhibited, as shown by immunohistochemistry and tissue myeloperoxidase quantitation. As a consequence, bacterial clearance from kidneys and bladders was drastically impaired. Antibody treatment of C3H/HeJ mice had only a marginal effect. The results show that neutrophils are essential for bacterial clearance from the urinary tract and that the neutrophil recruitment deficiency in C3H/HeJ mice explains their susceptibility to gram-negative UTI.

Expression of core 2 beta-1,6-N-acetylglucosaminyltransferase in a human pancreatic cancer cell line results in altered expression of MUC1 tumor-associated epitopes

Many tumor-associated epitopes possess carbohydrate as a key component, and thus changes in the activity of glycosyltransferases could play a role in generating these epitopes. In this report we describe the stable transfection of a human pancreatic adenocarcinoma cell line, Panc1-MUC1, with the cDNA for mucin core 2 GlcNAc-transferase (C2GnT), which creates the core 2 beta-1,6 branch in mucin-type glycans. These cells lack endogenous C2GnT activity but express a recombinant human MUC1 cDNA. C2GnT-transfected clones expressing different levels of C2GnT were characterized using monoclonal antibodies CC49, CSLEX-1, and SM-3, which recognize tumor-associated epitopes. Increased C2GnT expression led to greatly diminished expression of the CC49 epitope, which we identified as NeuAcalpha2,6(Galbeta1,3)GalNAcalpha-Ser/Thr in the Panc1-MUC1 cells. This was accompanied by the emergence of the CSLEX-1 epitope, sialyl Lewis x (NeuAcalpha2,3Galbeta1,4(Fucalpha1,3)GlcNAc-R), an important selectin ligand. Despite this, however, the C2GnT transfectants could not bind to selectins. Increased C2GnT expression also led to masking of the SM-3 peptide epitope, which persisted after the removal of sialic acid, further suggesting greater complexity of the core 2-associated O-glycans on MUC1. The results of this study suggest that C2GnT could play a regulatory role in the expression of certain tumor-associated epitopes.

Macrophage inflammatory protein-2 is required for neutrophil passage across the epithelial barrier of the infected urinary tract

IL-8 is a major human neutrophil chemoattractant at mucosal infection sites. This study examined the C-X-C chemokine response to mucosal infection, and, specifically, the role of macrophage inflammatory protein (MIP)-2, one of the mouse IL-8 equivalents, for neutrophil-epithelial interactions. Following intravesical Escherichia coli infection, several C-X-C chemokines were secreted into the urine, but only MIP-2 concentrations correlated to neutrophil numbers. Tissue quantitation demonstrated that kidney MIP-2 production was triggered by infection, and immunohistochemistry identified the kidney epithelium as a main source of MIP-2. Treatment with anti-MIP-2 Ab reduced the urine neutrophil numbers, but the mice had normal tissue neutrophil levels. By immunohistochemistry, the neutrophils were found in aggregates under the pelvic epithelium, but in control mice the neutrophils crossed the urothelium into the urine. The results demonstrate that different chemokines direct neutrophil migration from the bloodstream to the lamina propria and across the epithelium and that MIP-2 serves the latter function. These findings suggest that neutrophils cross epithelial cell barriers in a highly regulated manner in response to chemokines elaborated at this site. This is yet another mechanism that defines the mucosal compartment and differentiates the local from the systemic host response.

Interleukin-10 regulates quartz-induced pulmonary inflammation in rats

Interleukin-10 (IL-10) can downregulate expression of several proinflammatory cytokines including chemokines. This study investigated the role of IL-10 in the acute response of the rat lung to quartz particles. Intratracheal instillation of rats with 1 mg of quartz produced an inflammatory and cytotoxic response demonstrated by increased bronchoalveolar lavage (BAL) fluid neutrophils, lactate dehydrogenase, and protein. IL-10 was detected in rat lung, but IL-10 levels were not altered by quartz. In contrast, quartz increased lung levels of the chemokine macrophage inflammatory protein-2 (MIP-2). Treatment with recombinant murine IL-10 (rmIL-10) attenuated quartz-induced pulmonary inflammation and injury. Pretreatment with anti-IL-10 antiserum enhanced inflammatory responses to quartz. Consistent with effects on quartz-induced inflammation, rmIL-10 and anti-IL-10 serum decreased and increased, respectively, lung MIP-2 mRNA and protein in response to quartz. Additionally, rmIL-10 reduced production of hydrogen peroxide, superoxide anion, and nitric oxide by BAL cells from quartz-exposed and control rats. These results demonstrate that IL-10 is expressed in rat lung and downregulates quartz-induced inflammation and cell activation. The mechanism of the anti-inflammatory action of IL-10 after quartz administration involves, at least in part, attenuation of MIP-2 expression.

Expression and participation of eotaxin during mycobacterial (type 1) and schistosomal (type 2) antigen-elicited granuloma formation

Eotaxin participation was analyzed during types 1 and 2 lung granuloma formation induced by embolizing Sepharose beads coupled to purified protein derivative (PPD) of Mycobacterium bovis or soluble Ags derived from Schistosoma mansoni eggs. Eotaxin was monitored by protein ELISA and semiquantitative reverse-transcriptase PCR mRNA analysis. Both types 1 and 2 granulomas released eotaxin, but levels were sixfold greater (on day 4) in the type 2 than for the type 1 or foreign body granulomas. Transcripts for eotaxin, IL-4, and CCR3 (eotaxin receptor) were also enhanced during type 2 granuloma formation. Anti-IL-4 treatment impaired eotaxin mRNA in lungs with type 2 granulomas, indicating that IL-4 promoted local eotaxin expression. In vivo, anti-eotaxin treatment caused modest reductions in the size of both types 1 and 2 lesions, with negligible effect on eosinophil recruitment. Surprisingly, anti-eotaxin treatment abrogated IFN-gamma-producing cells in regional lymph nodes during the type 1 PPD response. Lymph nodes draining both types 1 and 2 lesions showed enhanced CCR3 mRNA, but this followed the time of maximum eotaxin protein and mRNA expression. Correlative, in vitro studies revealed that graded doses of eotaxin increased IFN-gamma production from PPD-sensitive regional lymph node cultures, while monocyte-chemotactic protein-1, an important macrophage chemoattractant, had the opposite effect. These findings indicate that eotaxin expression is not limited to type 2 hypersensitivity granulomas, but also promotes IFN-gamma production during mycobacterial responses.

MIP-1alpha as a critical macrophage chemoattractant in murine wound repair

At sites of injury, macrophages secrete growth factors and proteins that promote tissue repair. While this central role of the macrophage has been well studied, the specific stimuli that recruit macrophages into sites of injury are not well understood. This study examines the role of macrophage inflammatory protein 1alpha (MIP-1alpha), a C-C chemokine with monocyte chemoattractant capability, in excisional wound repair. Both MIP-1alpha mRNA and protein were detectable in murine wounds from 12 h through 5 d after injury. MIP-1alpha protein levels peaked 3 d after injury, coinciding with maximum macrophage infiltration. The contribution of MIP-1alpha to monocyte recruitment into wounds was assessed by treating mice with neutralizing anti-MIP-1alpha antiserum before injury. Wounds of mice treated with anti-MIP-1alpha antiserum had significantly fewer macrophages than control (41% decrease, P < 0. 01). This decrease in wound macrophages was paralleled by decreased angiogenic activity and collagen synthesis. When tested in the corneal micropocket assay, wound homogenates from mice treated with anti-MIP-1alpha contained significantly less angiogenic activity than control wound homogenates (27% positive for angiogenic activity versus 91% positive in the control group, P < 0.01). Collagen production was also significantly reduced in the wounds from anti-MIP-1alpha treated animals (29% decrease, P < 0.05). The results demonstrate that MIP-1alpha plays a critical role in macrophage recruitment into wounds, and suggest that appropriate tissue repair is dependent upon this recruitment.

Induction of gamma interferon production in human alveolar macrophages by Mycobacterium tuberculosis

Gamma interferon (IFN-gamma) is a cytokine which plays a critical role in resistance to Mycobacterium tuberculosis infection. While T lymphocytes and natural killer cells are a major source of IFN-gamma, previous demonstrations that it can be produced by murine macrophages prompted us to examine the capacity of human alveolar macrophages to express IFN-gamma. Here we report that in vitro infection of alveolar macrophages with M. tuberculosis induces both the release of IFN-gamma protein and a transient increase in IFN-gamma mRNA levels. The IFN-producing cells were shown to be macrophages by reverse transcription-in situ PCR. We also observed that M. tuberculosis stimulation resulted in IFN-gamma-dependent expression of the chemokines IFN-gamma-inducible protein 10 and monokine induced by IFN-gamma, suggesting that macrophage-derived IFN-gamma can function in an autocrine and/or paracrine manner. The existence of a positive regulatory loop was suggested by the observation that exogenous IFN-gamma protein could induce IFN-gamma mRNA expression in uninfected alveolar macrophages. Interleukin-12 was also found to be a potent inducer of IFN-gamma production, and M. tuberculosis-induced IFN-gamma production appears to be mediated, at least in part, by IL-12. In contrast, M. tuberculosis-induced IFN-gamma production by alveolar macrophages could be blocked by exogenous interleukin-10. These studies are the first to demonstrate an autoregulatory role for IFN-gamma produced by alveolar macrophages infected in vitro with M. tuberculosis.

Enhanced tumor-forming capacity for immortalized melanocytes expressing melanoma growth stimulatory activity/growth-regulated cytokine beta and gamma proteins

Three human MGSA/GRO genes encode 3 highly related chemokines, MGSA/GRO alpha, -beta and -gamma. All 3 MGSA/GRO proteins bind to the same receptors, but with differing affinities, and stimulate a number of biological responses including chemotaxis, angiogenesis, and growth regulation. We have previously demonstrated that MGSA/GRO alpha can be isolated from culture medium conditioned by malignant melanoma cells and that continuous secretion of MGSA/GRO alpha contributes to the transformation of immortalized murine melanocytes. The present study was designed to determine whether MGSA/GRO beta or -gamma have similar effects on melanocyte tumorigenicity. Stable Melan-a clones expressing either human MGSA/GRO beta or -gamma exhibited enhanced ability to form large colonies in soft agar and tumors in nude mice. The clones expressing the MGSA/GRO beta or -gamma transgene formed tumors within 2 months after injection; the tumors were highly pigmented and expressed immunoreactive MGSA/GRO beta or -gamma protein. Furthermore, when conditioned medium from Melan-a clones expressing MGSA/GRO alpha, -beta or -gamma transgenes were examined for the ability to induce angiogenesis in the rat cornea, strong angiogenic responses were observed. This angiogenic response was blocked by antibodies to the respective MGSA/GRO protein, but not by normal rabbit serum. By contrast, angiogenic responses were observed in only 2 of 12 corneal implants (17%) containing medium conditioned by Melan-a clones expressing the neomycin resistance marker alone.

Mechanism and biological significance of constitutive expression of MGSA/GRO chemokines in malignant melanoma tumor progression

By reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemistry, MGSA-alpha, -beta, -gamma, and CXCR2 mRNA expression and proteins are detected in 7 out of 10 human melanoma lesions. The biological consequence of constitutive expression of the MGSA/GRO chemokine in immortalized melanocytes was tested in SCID and nude mouse models. Continuous expression of MGSA/GRO-alpha, -beta, or -gamma in immortalized melan-a mouse melanocytes results in nearly 100% tumor formation for each of the clones tested, whereas clones expressing only the neomycin resistance vector form tumors <10% of the time. Moreover, antibodies to the MGSA/GRO proteins slow or inhibit the formation of tumors in the SCID mouse model and block the angiogenic response to conditioned medium from the tumor-producing clones. Transcription of the MGSA/GRO chemokines is regulated by an enhancesome-like complex comprised of the nuclear factor-kappaB (NF-kappaB), HMG(I)Y, IUR, and Sp1 elements. In Hs294T melanoma cells the half life of the IKB protein is shortened in comparison to normal retinal epithelial cells, facilitating the endogenous nuclear localization of NF-kappaB. We propose that this endogenous nuclear NF-kappaB, working in concert with the 115-kDa IUR-binding factor, promotes constitutive expression of MGSA/GRO genes.

In vitro transendothelial migration of blood T lymphocytes from HIV-infected individuals

OBJECTIVE

We hypothesized that differential extravasation of circulating CD4+ or CD8+ T lymphocytes contributes to HIV-associated CD8+ lymphocytic alveolitis. Differences in T-cell transendothelial migration may be intrinsic or emerge at sites where vascular endothelium is activated by overexpression of tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma.

DESIGN

We used an in vitro model of lymphocyte extravasation to assess transendothelial migration of peripheral blood mononuclear cells (PBMC) from HIV-positive individuals. We assayed bronchoalveolar lavage (BAL) fluid from HIV-positive and normal individuals to determine if increased levels of TNF-alpha and IFN-gamma were present in the lungs of HIV-infected individuals.

METHODS

Transendothelial migration was assessed by determining the number and flow cytometric phenotype of PBMC adherent to or migrating across unstimulated or TNF-alpha and IFN-gamma-activated endothelial cell monolayers. We measured BAL fluid cytokine concentrations using standard antigen-capture enzyme-linked immunosorbent assays for TNF-alpha and IFN-gamma.

RESULTS

T cells migrating across unactivated endothelial cells were significantly enriched for CD4+ T cells. Cytokine activation of endothelial cells allowed significantly greater transendothelial migration of CD8+ T cells compared to unactivated endothelial cells. TNF-alpha was increased in BAL fluid from HIV-positive individuals relative to controls.

CONCLUSIONS

These data suggest that, in HIV-positive individuals, CD4+ T cells are migration competent and blood CD8+ T cells do not have enhanced migration competence relative to CD4+ T cells. CD8+ T cell extravasation is aided by TNF-alpha and IFN-gamma-induced endothelial cells activation.

Enhanced tumor-forming capacity for immortalized melanocytes expressing melanoma growth stimulatory activity/growth-regulated cytokine beta and gamma proteins

Three human MGSA/GRO genes encode 3 highly related chemokines, MGSA/GRO alpha, -beta and -gamma. All 3 MGSA/GRO proteins bind to the same receptors, but with differing affinities, and stimulate a number of biological responses including chemotaxis, angiogenesis, and growth regulation. We have previously demonstrated that MGSA/GRO alpha can be isolated from culture medium conditioned by malignant melanoma cells and that continuous secretion of MGSA/GRO alpha contributes to the transformation of immortalized murine melanocytes. The present study was designed to determine whether MGSA/GRO beta or -gamma have similar effects on melanocyte tumorigenicity. Stable Melan-a clones expressing either human MGSA/GRO beta or -gamma exhibited enhanced ability to form large colonies in soft agar and tumors in nude mice. The clones expressing the MGSA/GRO beta or -gamma transgene formed tumors within 2 months after injection; the tumors were highly pigmented and expressed immunoreactive MGSA/GRO beta or -gamma protein. Furthermore, when conditioned medium from Melan-a clones expressing MGSA/GRO alpha, -beta or -gamma transgenes were examined for the ability to induce angiogenesis in the rat cornea, strong angiogenic responses were observed. This angiogenic response was blocked by antibodies to the respective MGSA/GRO protein, but not by normal rabbit serum. By contrast, angiogenic responses were observed in only 2 of 12 corneal implants (17%) containing medium conditioned by Melan-a clones expressing the neomycin resistance marker alone.

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.

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.

Constitutive activation of 5-lipoxygenase in the lungs of patients with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive disorder characterized by inflammation, fibroblast proliferation, and accumulation of extracellular matrix proteins. Leukotrienes (LTs) are pro-inflammatory and pro-fibrogenic mediators derived from the 5-lipoxygenase (5-LO) pathway of arachidonic acid metabolism. They are thought to play a role in a number of disease processes, but have received relatively little attention in investigations into the pathogenesis of IPF. In this study, we measured the levels of immunoreactive LTs B(4) and C(4) in homogenates of lung tissue obtained from patients with newly diagnosed, untreated IPF, as compared to levels measured in homogenates of uninvolved nonfibrotic lung tissue from patients undergoing resectional surgery for bronchogenic carcinoma. Compared to homogenates on nonfibrotic control lung, homogenates from IPF patients contained 15-fold more LTB(4) and 5-fold more LTC(4). IPF homogenate levels of LTB(4) were significantly correlated with histologic indices of both inflammation (r=0.861) and fibrosis (r=0.926). Activation of 5-LO is known from in vitro studies to be associated with localization of the enzyme at the nuclear membrane. Immunohistochemical staining for 5-LO protein in alveolar macrophages (AMs) demonstrated that such an "activated" localization pattern was significantly more frequent in IPF lung (19.2+/-3.3% of cells) than in control lung (9.3+/-0.9%); this localization pattern was rarely seen (3.2%) in sections from a truly normal transplant donor lung. Consistent with these data, AMs obtained from IPF patients by bronchoalveolar lavage, purified by adherence, and cultured in the absence of a stimulus for 16 h elaborated significantly greater amounts of LTB(4) and LTC(4) than did control AMs obtained from normal volunteers. These data indicate that the 5-LO pathway is constitutively activated in the lungs of patients with IPF, and the AM represents at least one cellular source of LT overproduction in this disorder. We speculate that LTs participate in the pathogenesis of IPF, and their overproduction in this disorder may be amenable to specific pharmacotherapy.

Severe combined immunodeficiency mouse and human psoriatic skin chimeras. Validation of a new animal model

Research into the cause and pathophysiological mechanisms underlying expression of psoriatric skin lesions has been hampered by lack of an appropriate animal model for this common and enigmatic cutaneous disease. These studies characterize normal skin, pre-psoriatic skin, and psoriatic plaque skin samples transplanted onto severe combined immunodeficiency mice. In this report we document that 1), normal, prepsoriatic, and psoriatic plaque keratome skin samples can be transplanted onto severe combined immunodeficiency mice reliably with high rates of graft survival (> 85%) and with reproducible changes consistently observed over prolonged periods of engraftment; 2), after transplantation, by clinical assessment and routine light microscopy, normal skin remained essentially normal whereas pre-psoriatic skin became thicker, and psoriatic plaque skin retained its characteristic plaque-type elevation and scale; 3), by using a panel of antibodies and immunohistochemical analysis, the overall phenotype of human cell types (including immunocytes) that persisted in the transplanted skin was remarkably similar to the immunophenotype of pretransplanted skin samples; 4), clearly recognized interface zones between human and murine skin within the epidermal and dermal compartments could be identified by routine microscopy and immunostaining, with focal areas of chimerism; and 5), elevated interleukin 8 cytokine levels were present in transplanted pre-psoriatic and psoriatic plaque skin samples. We conclude that there are many similarities between pre- and post-transplanted human samples of normal and psoriatic skin that are grafted onto severe combined immunodeficiency mice. Thus, we propose that this new animal model is appropriate for additional mechanistic-type studies designed to reveal the underlying genetic/etiological abnormality, as well as better illuminate the pathophysiological basis, for this important skin disease.

Intercellular adhesion molecule-1 mediates the expression of monocyte-derived MIP-1 alpha during monocyte-endothelial cell interactions

The extravasation of leukocytes from the lumen of the vessel to a site of inflammation initially requires a specific binding event followed by migration of the cells through the endothelial cell layer into the inflammatory foci. The interaction of leukocytes with the endothelium via specific receptors may provide intracellular signals that activate the cells. In the present study we have investigated the production of MIP-1 alpha, a mononuclear cell chemotactic protein, during monocyte:endothelial cell interactions. Neither unstimulated nor interferon (IFN)-stimulated human umbilical vein endothelial cells (HUVECs) produced substantial MIP-1 alpha protein. However, the addition of enriched monocyte populations with unstimulated HUVECs resulted in the production of MIP-1 alpha. Monocytes cultured with IFN-gamma-activated HUVECs showed an additional increase in MIP-1 alpha production. Immunohistochemical analysis demonstrated that the monocyte was the cellular source of MIP-1 alpha production in this coculture system. The mechanism of MIP-1 alpha expression was further assessed by determining the role of adhesion molecules in the regulation of MIP-1 alpha production during monocyte:HUVEC interactions. To attenuate the increased production of MIP-1 alpha by the monocyte:HUVEC interaction, anti-adhesion molecule monoclonal antibodies (MoAbs) were added to the cultures. Addition of anti-ICAM-1 neutralizing MoAbs significantly inhibited the production of MIP-1 alpha, whereas neutralizing anti-VCAM-1 MoAbs failed to block MIP-1 alpha production. Furthermore, MIP-1 alpha production was induced in monocytes cultured on ICAM-1-coated plates. These results indicate an intimate relationship between leukocyte-endothelial cells, adhesion molecule, and the expression of the monocyte-derived chemokine MIP-1 alpha during cellular adhesion. This mechanism may serve an important role in cell activation and recruitment of leukocytes during the initiation of an inflammatory response.

Monocyte chemoattractant protein production in red cell incompatibility

BACKGROUND

Mononuclear phagocytes play a central role in hemolytic transfusion reactions by erythrophagocytosis and production of inflammatory mediators. Factors that affect the number or function of monocyters would be expected to alter the clinical course of hemolytic transfusion reactions, and thus the production of monocyte chemoattractant protein-1 (MCP-1), a recently described chemotactic and activating cytokine specific for monocytes, was investigated in two distinct settings of red cell (RBC) incompatibility.

STUDY DESIGN AND METHODS

Fresh heparinized whole blood was incubated with ABO-compatible or -incompatible RBCs. Isolated peripheral blood mononuclear cells were incubated with anti-D-coated or uncoated RBCs. MCP-1 was measured in the plasma or culture medium by enzyme-linked immunosorbent assay. MCP-1 gene expression was detected by Northern blot analysis of buffy coat or mononuclear cell total RNA.

RESULTS

Significant levels of MCP-1 protein in plasma or medium were detected 24 hours after the addition of incompatible RBCs, but not in the first 6 hours. Nonimmune hemolysis of added RBCs did not stimulate MCP-1 production. The inactivation of complement by heat treatment of plasma prior to the addition of RBCs to whole blood did not prevent MCP-1 production. Nor did neutralizing antibodies to tumor necrosis factor prevent MCP-1 production in ABO incompatibility. MCP-1 production was associated with increased steady-state levels of white cell MCP-1 mRNA, which occurred more rapidly in ABO than Rh incompatibility.

CONCLUSION

The monocyte-specific chemotactic cytokine MCP-1 is produced by peripheral blood leukocytes in response to RBC incompatibility. MCP-1 may act in a positive feedback loop to recruit and activate monocytes during hemolytic transfusion reactions, thus contributing to the maintenance of these reactions.

Cytokine production in IgG-mediated red cell incompatibility

The transfusion of incompatible red cells may result in fever and systemic symptoms. The mechanisms by which these symptoms are produced in the setting of antibodies that do not usually fix complement, as in the Rh system, are obscure. It has been hypothesized, on the basis of their known biologic activities, that a specific set of cytokines may be involved in such transfusion reactions. Therefore, the production of the inflammatory cytokines interleukin-1 beta (IL-1 beta), tumor necrosis factor (TNF), interleukin-6 (IL-6), and interleukin-8 (IL-8) by human monocytes in response to red cells sensitized with anti-D was investigated, as a model of IgG-dependent hemolytic transfusion reactions. IL-1 beta, IL-6, and IL-8 were detectable in the culture supernatants at 4 to 6 hours and increased up to 24 hours, whereas TNF peaked at 6 hours. Immunocytochemical stains of cell preparations demonstrated IL-1 beta, IL-8, and TNF in monocytes engaged in erythrophagocytosis. IL-8 production and phagocytosis could be inhibited by monomeric IgG, but Fab fragments of a monoclonal antibody specific for the low-affinity IgG receptor Fc gamma RII could not be, which suggests the involvement of the high-affinity receptor Fc gamma RI. Neutralizing antisera to IL-1 beta and TNF did not abrogate the production of IL-8, which suggests that sensitized red cells serve as a primary signal for this cytokine. These findings indicate that the production of inflammatory cytokines by phagocytes may be responsible for the symptomatology of IgG-mediated hemolytic transfusion reactions.

Expression of interleukin-8 by lipopolysaccharide-stimulated bone marrow-derived mononuclear cells

Interleukin-8 (IL-8) is a potent neutrophil chemoattractant, produced by a variety of immune and nonimmune cells in response to exogenous and host-derived inflammatory stimuli. We demonstrate here that a suspension of normal bone marrow mononuclear cells, consisting principally of myeloid precursors, produces IL-8 in response to stimulation with lipopolysaccharide (LPS). IL-8-specific mRNA is rapidly induced, being detected first 30 min after stimulation. IL-8 is detected by enzyme-linked immunosorbent assay within 2 h of stimulation, with steady a increase in its level through 72 h. Further studies demonstrated that LPS could serve as a primary stimulus for the expression of IL-8, since LPS challenge in the presence of cycloheximide resulted in superinduction of bone marrow mononuclear cell-derived IL-8 mRNA. These investigations suggest that the stimulatory effect of LPS is independent of other cytokines such as IL-1 beta. When compared with LPS, IL-1 beta proved to be a weak signal for the expression of IL-8 by bone marrow mononuclear cells. In a dose-response study, the maximum stimulatory concentration of IL-1 beta (300 pg/ml) resulted in the production of 500 pg of IL-8 per 10(6) cells, whereas 1 microgram of LPS resulted in the production of 5.5 ng/10(6) cells. Although IL-1 beta was not a particularly potent stimulus for IL-8 production by bone marrow mononuclear cells, peripheral blood mononuclear cells were highly susceptible to IL-1 beta challenge. In addition, the potential dependence of LPS-induced marrow-derived IL-8 production on the intermediate synthesis of IL-1 beta was further investigated. Results of studies assessing kinetics, addition of cycloheximide, and blocking with IL-1 beta neutralizing antibody were all consistent with the ability of LPS to directly induce bone marrow-derived IL-8 independently of IL-1 beta. These investigations demonstrate that bone marrow may be a significant source of IL-8 and may play a significant role in acute infectious, inflammatory responses.

Rapid decline in the behavioral response of paradise fish (Macropodus opercularis) to prostaglandin F2 alpha treatment

Prostaglandins (PGs) can affect sexual behavior in a range of vertebrates including goldfish, paradise fish, lizards, frogs, hamsters, and rats. Behavioral responsiveness to PG treatment has not previously been reported to correlate with reproductive condition. Earlier work (Villars et al., 1985) has suggested that in paradise fish, response to PG treatment may be limited to the period immediately following spawning. In the present experiment, prespawned females were tested for their response to intraperitoneal injection of PGF2 alpha (300 ng/g body wt) at 1 (n = 10), 3 (n = 8), or 5 (n = 8) days postspawning. Only pairs tested 1 day postspawning responded to PG-treatment of the female with spawning acts (curving or inverting). Moreover, 1 day PG-treated females showed significantly increased sexual motivation, as measured by the time the female spent under the nest with a nest-building male and by the frequency of female sexual solicitation, while the 3-day and the 5-day postspawning females showed no discernible response to PG treatment. Though differential behavioral experience had been suspected to account for female unresponsiveness seen in earlier work, it now seems possible that physiological changes post spawning may render the females unresponsive to PG treatment.

Hemostasis changes during cardiopulmonary bypass surgery

A number of hemostasis parameters were studied in a total of 63 patients undergoing cardiopulmonary bypass (CPB) for open heart surgery. In 33 patients fibrinogen, Factors II, V, VIII:C, X, XI, antithrombin, plasminogen, alpha 2-antiplasmin, and platelet counts were assayed before surgery, during maximal hypothermia, at the end of the bypass procedure, before and after protamine sulfate infusion, in the intensive care unit, and 48 hours postoperatively. All factors assayed decreased markedly when the patients were placed on the bypass machine, the drop fairly well paralleling the decrease in hematocrit. During bypass the factors remained low, although a slight tendency toward an increase was noted. Only platelet counts remained low with a decreasing trend until the end of bypass. In the intensive care unit a second decrease in fibrinogen, Factors II and V and antithrombin was noted. This drop was unrelated to four patients who experienced a greater blood loss during this time than the others. Forty-eight hours postoperatively, a marked increase could be found in all clotting factors and near normal levels were measured. Platelet counts remained low, however. The decrease in factors rarely dropped into a range where one would expect a compromised hemostasis (less than 30%). Although antithrombin levels decreased below 60%, no difficulties with heparinization were encountered. Several factors were assayed manually and by automated analyzer (Multistat III), and excellent correlations were found between both procedures. Also a good correlation was found between the activated whole blood clotting times and quantitative heparin assays. In 30 additional patients platelet function was studied before surgery, after thoracotomy, after heparin administration, after initiation of bypass, at maximal hypothermia, before and after protamine sulfate infusion, and 24 hours postoperatively. Platelet counts once again decreased as patients were placed on the CPB machine and remained low throughout the procedure. Mean platelet volumes were unchanged until protamine was given. At that time, a significant drop in mean platelet volume was recorded. Twenty-four hours postoperatively the volumes were normal again. Platelet aggregation studies were performed on a whole blood aggregometer using two concentrations of ADP, collagen, and ristocetin as aggregation inducers. A significant decrease in aggregability was seen when the patients were connected to the CPB apparatus.(ABSTRACT TRUNCATED AT 400 WORDS)

Changes in antithrombin, antiplasmin, and plasminogen during and after cardiopulmonary bypass

Platelet counts and several clotting parameters, especially antithrombin, alpha 2-antiplasmin, and plasminogen, were determined in 33 patients undergoing cardiopulmonary bypass surgery. Except for Factors VIII and XI, all activities measured fell significantly as the patients were placed on the pump. This initial drop paralleled the drop in hematocrit, i.e., the drop was most likely due to hemodilution. During the entire procedure the activities remained decreased, again paralleling the hematocrit. Only the drop in platelet counts was greater than the hematocrit, suggesting additional consumption during bypass. In the ICU a second significant drop in antithrombin, prothrombin, and Factor V was noted that was not reflected by a drop in hematocrit. The cause for this is not known at this time. Although the patients with the lowest antithrombin levels, compared to the highest levels in the ICU seemed to have a greater need for protamine and blood and had greater chest tube drainage, none of these changes were significantly different. Comparisons between activated clotting times (ACTs) and actual heparin levels revealed a good correlation (0.886). Good correlations were also noted when manual factor assays were compared with automated assays using an automated analyzer suggesting the potential use of automation and profiling for these patients. Possible reasons for some of the most commonly encountered postoperative bleeding problems are discussed.