Upregulation Of Intercellular Adhesion Molecule-1 Research Articles

Endothelial Cell Changes Are Associated with Pulmonary Edema and Respiratory Distress in Mice Infected with the WA1 Human Babesia Parasite

A C3H/HeN mouse model was established to study the pathogenesis of the human babesial parasites, WA1 and Babesia microti. To evaluate the course of parasitemia and the associated lesions, mice were inoculated intraperitoneally with either WA1-infected, B. microti-infected, or uninfected hamster red blood cells. WA1-infected mice developed dyspnea and moderate parasitemias, after which death occurred. Babesia microti-infected mice experienced low parasitemias with no apparent morbidity or mortality. WA1-infected mice were thrombocytopenic but not anemic. Hemograms for B. microti-infected mice were similar to controls. Postmortem examination of WA1-infected mice revealed prominent lesions in the lungs, including pulmonary edema and intravascular margination of leukocytes. No pulmonary changes were detected in B. microti-infected mice. Blood gas measurements of WA1-infected mice showed reduced oxygen saturation and pH, and increased carbonic acid compared to controls, indicating hypoxia and respiratory acidosis. Ultrastructure studies of WA1-infected lungs showed hypertrophied endothelial cells containing transcellular channels associated with protein-rich intra-alveolar fluid. Endothelial cell activation was demonstrated by an upregulation of intercellular adhesion molecule-1 in the lungs of WA1-infected mice. The results suggest that recruitment of inflammatory cells to the lungs in WA1-infected mice induces endothelial cell alterations, leading to pulmonary edema and acute respiratory failure.

Mechanisms underlying the anti-inflammatory actions of central corticotropin-releasing factor.

Immune activation of hypothalamic corticotropin-releasing factor (CRF) provides a negative feedback mechanism to modulate peripheral inflammatory responses. We investigated whether central CRF attenuates endothelial expression of intercellular adhesion molecule 1 (ICAM-1) and leukocyte recruitment during endotoxemia in rats and determined its mechanisms of action. As measured by intravital microscopy, lipopolysaccharide (LPS) induced a dose-dependent increase in leukocyte rolling, adhesion, and emigration in mesenteric venules, which was associated with upregulation of endothelial ICAM-1 expression. Intracisternal injection of CRF abrogated both the increased expression of ICAM-1 and leukocyte recruitment. Intravenous injection of the specific CRF receptor antagonist astressin did not modify leukocyte-endothelial cell interactions induced by a high dose of LPS but enhanced leukocyte adhesion induced by a low dose. Blockade of endogenous glucocorticoids but not alpha-melanocyte-stimulating hormone (alpha-MSH) receptors reversed the inhibitory action of CRF on leukocyte-endothelial cell interactions during endotoxemia. In conclusion, cerebral CRF blunts endothelial upregulation of ICAM-1 and attenuates the recruitment of leukocytes during endotoxemia. The anti-inflammatory effects of CRF are mediated by adrenocortical activation and additional mechanisms independent of alpha-MSH.

Tumor necrosis factor-alpha contributes to ischemia- and reperfusion-induced endothelial activation in isolated hearts.

-During myocardial reperfusion, polymorphonuclear neutrophil (PMN) adhesion involving the intercellular adhesion molecule-1 (ICAM-1) may lead to aggravation and prolongation of reperfusion injury. We studied the role of early tumor necrosis factor-alpha (TNF-alpha) cleavage and nuclear factor-kappaB (NF-kappaB) activation on ICAM-1 expression and venular adhesion of PMN in isolated hearts after ischemia (15 minutes) and reperfusion (30 to 480 minutes). NF-kappaB activation (electromobility shift assay) was found after 30 minutes of reperfusion and up to 240 minutes. ICAM-1 mRNA, assessed by Northern blot, increased during the same interval. Functional effect of newly synthesized adhesion molecules was found by quantification (in situ fluorescence microscopy) of PMN, given as bolus after ischemia, which became adherent to small coronary venules (10 to 50 microm in diameter). After 480 minutes of reperfusion, ICAM-1-dependent PMN adhesion increased 2.5-fold compared with PMN adhesion obtained during acute reperfusion. To study the influence of NF-kappaB on PMN adhesion, we inhibited NF-kappaB activation by transfection of NF-kappaB decoy oligonucleotides into isolated hearts using HJV-liposomes. Decoy NF-kappaB but not control oligonucleotides blocked ICAM-1 upregulation and inhibited the subacute increase in PMN adhesion. Similar effects were obtained using BB 1101 (10 microg), an inhibitor of TNF-alpha cleavage enzyme. These data suggest that ischemia and reperfusion in isolated hearts cause liberation of TNF-alpha, activation of NF-kappaB, and upregulation of ICAM-1, an adhesion molecule involved in inflammatory response after ischemia and reperfusion.

Upregulation of ICAM-1 on cardiomyocytes in jeopardized human myocardium during infarction.

Impaired perfusion of the myocardium induces a local inflammatory response. In animal models, there is ample evidence that polymorphonuclear leucocytes (PMNs) infiltrating infarcted myocardium contribute significantly to infarct size. To explore a possible role for PMNs in the tissue damage of human myocardial infarction, we investigated localization of intercellular adhesion molecule-1 (ICAM-1) and CD66b (previously clustered as CD67), a marker of degranulation of human PMNs, in relation to deposition of complement in tissue specimens of infarcted and healthy parts of the heart obtained from 20 patients, who had died following acute myocardial infarction. ICAM-1 was transiently expressed by endothelium and for a longer period (few days) on myofibers of infarcted myocardium. This expression only occurred in parts that stained positive for complement. PMN infiltration exclusively occurred in areas with ICAM-1 expression, but not every ICAM-1-positive area contained PMN infiltrates. CD66b was found in PMNs but was also fixed to the plasma membrane of myofibers that stained positive for complement and ICAM-1. These findings indicate that, in infarcted human myocardium, PMNs are degranulated, possibly upon interaction with ICAM-1 and activated complement.

Invasion of human mucosal epithelial cells by Neisseria gonorrhoeae upregulates expression of intercellular adhesion molecule 1 (ICAM-1).

Infection of the mucosa by Neisseria gonorrhoeae involves adherence to and invasion of epithelial cells. Little is known, however, about the expression by mucosal epithelial cells of molecules that mediate cellular interactions between epithelial cells and neutrophils at the site of gonococcal infection. The aim of this study was to determine the expression of intercellular adhesion molecule 1 (ICAM-1) by epithelial cells during the process of gonococcal invasion. The highly invasive strain FA1090 and the poorly invasive strain MS11 were incubated with human endometrial adenocarcinoma (HEC-1-B) or human cervical carcinoma (ME-180) epithelial cells, after which ICAM-1 expression was measured by flow cytometry. After 15 h of infection with FA1090, expression of ICAM-1 increased 4.7- and 2.1-fold for HEC-1-B and ME-180 cells, respectively, whereas 15 h of infection of HEC-1-B cells with MS11 increased ICAM-1 expression only 1.6-fold. ICAM-1 expression was restricted to the cell surface, since no soluble ICAM-1 was detected. The distribution of staining was heterogeneous and mimicked that seen after treatment of HEC-1-B cells with the ICAM-1 agonist tumor necrosis factor alpha (TNF-alpha) in the absence of bacteria. PCR and dot blot analyses of ICAM-1 mRNA showed no change in levels over time in response to infection. Although TNF-alpha was produced by HEC-1-B cells after infection, the extent of ICAM-1 upregulation was not affected by neutralizing anti-TNF-alpha antiserum. Dual-fluorescence flow cytometry showed that the cells with the highest levels of ICAM-1 expression were cells with associated gonococci. We conclude that epithelial cells upregulate the expression of ICAM-1 in response to infection with invasive gonococci. On the mucosa, upregulation of ICAM-1 by infected epithelial cells may function to maintain neutrophils at the site of infection, thereby reducing further invasion of the mucosa by gonococci.

Enzymatically modified, nonoxidized LDL induces selective adhesion and transmigration of monocytes and T-lymphocytes through human endothelial cell monolayers.

Circulating monocytes and T lymphocytes extravasate through the endothelium at sites of developing atheromatous lesions, where they tend to accumulate and mediate the progression of the disease. We have previously demonstrated the presence of an enzymatically degraded, nonoxidized form of LDL (E-LDL) in early human fatty streaks, which possesses major biological properties of an atherogenic lipoprotein. The effects of E-LDL on human endothelial cells have now been studied with respect to adhesion and transmigration of monocytes and T lymphocytes. E-LDL induced a rapid and dose-dependent selective adhesion of monocytes and T lymphocytes to endothelial cell monolayers within 30 minutes of incubation. Maximal increases in the number of adherent monocytes (8-fold) and of adherent T lymphocytes (4-fold) were observed after treatment with 50 microg/mL E-LDL. E-LDL was more active than oxidized LDL (ox-LDL), whereas native LDL produced only minor adhesive effects. Both E-LDL and ox-LDL enhanced transmigration of monocytes and of T lymphocytes through endothelial monolayers. Again, E-LDL was more potent than ox-LDL, inducing transmigration to a similar extent as N-formyl-Met-Leu-Phe. In endothelial cells, E-LDL stimulated upregulation of intercellular adhesion molecule-1 (ICAM-1), platelet-endothelial cells adhesion molecule-1 (PECAM-1), P-selectin, and E-selectin with distinct kinetics. Analyses with blocking antibodies indicated that ICAM-1 and P-selectin together mediated approximately 70% of cell adhesion, whereas blocking of PECAM-1 had no effect on adhesion but reduced transmigration to less than 50% of controls. E-LDL also upregulated expression of ICAM-1 in human aortic smooth muscle cells, and this correlated with increased adhesion of T lymphocytes. E-LDL is thus able to promote the selective adhesion of monocytes and T lymphocytes to the endothelium, stimulate transmigration of these cells, and foster their retention in the vessel wall by increasing their adherence to smooth muscle cells. These findings underline the potential significance of E-LDL in the pathogenesis of atherosclerosis.

Specificities of CD40 signaling: involvement of TRAF2 in CD40-induced NF-kappaB activation and intercellular adhesion molecule-1 up-regulation.

Several tumor necrosis factor receptor-associated factor (TRAF) family proteins including TRAF2, TRAF3, TRAF5, and TRAF6, as well as Jak3, have been implicated as potential mediators of CD40 signaling. An extensive in vitro binding study indicated that TRAF2 and TRAF3 bind to the CD40 cytoplasmic tail (CD40ct) with much higher affinity than TRAF5 and TRAF6 and that TRAF2 and TRAF3 bind to different residues of the CD40ct. Using CD40 mutants incapable of binding TRAF2, TRAF3, or Jak3, we found that the TRAF2-binding site of the CD40ct is critical for NF-kappaB and stress-activated protein kinase activation, as well as the up-regulation of the intercellular adhesion molecule-1 (ICAM-1) gene, whereas binding of TRAF3 and Jak3 is dispensable for all of these functions. Overexpression of a dominantly active IkappaBalpha strongly inhibited CD40-induced NF-kappaB activation, ICAM-1 promoter activity, and cell-surface ICAM-1 up-regulation. These studies suggest a potential signal transduction pathway from the CD40 receptor to the transcriptional activation of the ICAM-1 gene.

Interferon-?-induced ICAM-1 and CD40 expression, complete lack of HLA-DR and CD80 (B7.1), and inconsistent HLA-ABC expression in basal cell carcinoma: a possible role for interleukin-10?

Basal cell carcinomas (BCCs) of the skin show varying degrees of peritumoural inflammatory infiltrate consisting mainly of T cells, but lack an effective T-cell-mediated immune response. This may be caused by the absence of the major histocompatibility complex (MHC) class I and II antigens, intercellular adhesion molecule-1 (ICAM-1), CD40 and CD80 (B7.1). Interferon-gamma (IFN-gamma) is known to induce or up-regulate their expression on epithelial cells, whereas interleukin-10 (IL-10) down-regulates their expression. The induction and up-regulation of HLA-ABC, HLA-DR, ICAM-1, CD40, and CD80 in BCC and normal skin from BCC patients were investigated in a culture system using recombinant human IFN-gamma (rHuIFN-gamma). The levels of IL-10 were determined in the supernatants after culture. The results showed that only ICAM-1 expression was significantly up-regulated on BCC cells. However, in the normal epidermis of BCC patients and in the epidermis overlying the tumour nests, significant up-regulation of ICAM-1, and CD40, and CD80 and slight up-regulation of HLA-DR were observed. No changes in HLA-ABC expression were observed in either normal skin or BCC. High levels of IL-10 were present in the supernatants of BCC biopsies after culture. It may be concluded that it is highly likely that the presence of IL-10 in BCC is directly or indirectly responsible for the complete lack of expression of HLA-DR, ICAM-1, CD40 and CD80 and the inconsistent expression of HLA-ABC on BCC cells in situ and may be a way of escaping immune survillance.

Blockade of poly(ADP-ribose) synthetase inhibits neutrophil recruitment, oxidant generation, and mucosal injury in murine colitis

Background & Aims: Inflammatory bowel disease is characterized by oxidative and nitrosative stress, leukocyte infiltration, and up-regulation of intercellular adhesion molecule 1 (ICAM-1) expression in the colon. Recent data show that oxidative and nitrosative stress in isolated enterocytes produces DNA single-strand breaks that activate the nuclear enzyme poly(ADP-ribose) synthetase (PARS), resulting in depletion of intracellular energetics and increased paracellular permeability. The aim of the present study was to examine the in vivo relevance of this injury pathway. Methods: Colitis was induced by rectal instillation of trinitrobenzenesulfonic acid (TNBS) in mice with a genetic deficiency of PARS (PARS −/−) and in wild-type littermates. Results: In wild-type mice, TNBS treatment resulted in colonic erosion and ulceration that was maintained up to 7 days. Neutrophil infiltration (indicated by myeloperoxidase activity in the mucosa) was associated with up-regulation of ICAM-1 and high levels of malondialdehyde and nitrotyrosine. TNBS-treated PARS −/− mice experienced a similar colonic injury that was, however, completely resolved by 6 days. Resolution of the damage was associated with absence of ICAM-1 up-regulation, reduction of neutrophil infiltration, lipid peroxidation, and nitrosative damage. Conclusions: These data show that PARS plays a critical role in colonic inflammation possibly by regulating ICAM-1 expression, neutrophil recruitment, and the subsequent oxidant generation. GASTROENTEROLOGY 1999;116:335-345

BLOCKADE OF POLY (ADP-RIBOSE) SYNTHETASE INHIBITS NEUTROPHIL RECRUITMENT, OXIDANT GENERATION, AND MUCOSAL INJURY IN MURINE COLITIS

Abstract Background & Aims: Inflammatory bowel disease is characterized by oxidative and nitrosative stress, leukocyte infiltration, and up-regulation of intercellular adhesion molecule 1 (ICAM-1) expression in the colon. Recent data show that oxidative and nitrosative stress in isolated enterocytes produces DNA single-strand breaks that activate the nuclear enzyme poly(ADP-ribose) synthetase (PARS), resulting in depletion of intracellular energetics and increased paracellular permeability. The aim of the present study was to examine the in vivo relevance of this injury pathway. Methods: Colitis was induced by rectal instillation of trinitrobenzenesulfonic acid (TNBS) in mice with a genetic deficiency of PARS (PARS −/− ) and in wild-type littermates. Results: In wild-type mice, TNBS treatment resulted in colonic erosion and ulceration that was maintained up to 7 days. Neutrophil infiltration (indicated by myeloperoxidase activity in the mucosa) was associated with up-regulation of ICAM-1 and high levels of malondialdehyde and nitrotyrosine. TNBS-treated PARS −/− mice experienced a similar colonic injury that was, however, completely resolved by 6 days. Resolution of the damage was associated with absence of ICAM-1 up-regulation, reduction of neutrophil infiltration, lipid peroxidation, and nitrosative damage. Conclusions: These data show that PARS plays a critical role in colonic inflammation possibly by regulating ICAM-1 expression, neutrophil recruitment, and the subsequent oxidant generation. GASTROENTEROLOGY 1999;116:335-345

Proinflammatory Potential of Cytomegalovirus Infection

We observed the effects of antiviral therapy on CMV and/or oxidative-stress-induced stimulation of proinflammatory molecules including interleukin-8 (IL-8), melanoma growth stimulatory activity-α (GRO-α) and intercellular adhesion molecule 1 (ICAM-1) using human foreskin fibroblasts. Ganciclovir, foscarnet or cidofovir completely suppressed virus replication, as demonstrated by CMV late (L) antigen production. These drugs did not influence CMV immediate-early (IE) antigen expression and had no effects on CMV-induced cellular changes in IL-8, GRO-α and ICAM-1 levels. Phosphorothioate oligonucleotide (ISIS 2922) suppressed both CMV IE and L antigen by 99%. ISIS 2922 completely suppressed CMV-induced upregulation of both chemokines and ICAM-1. Induction of oxidative stress by H₂O₂ upregulated IL-8 expression. Oxidative stress and CMV infection showed synergistic effects on IL-8 expression. ISIS 2922 only partially inhibited the upregulation of IL-8 in infected cells treated with H₂O₂, whereas cotreatment with ISIS 2922 and antioxidants inhibited the upregulation almost completely. The results showed that inhibition of CMV IE expression alone or in combination with antioxidants is promising for the treatment of CMV disease.

Transcriptional regulation of the intercellular adhesion molecule-1 gene by proinflammatory cytokines in human astrocytes.

Intercellular adhesion molecule-1 (ICAM-1) expression is upregulated by cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and interferon-gamma (IFN-gamma) in numerous cell types including the astrocyte, which functions as an immunoregulatory cell within the central nervous system. We investigated the mechanism by which ICAM-1 is transcriptionally regulated by proinflammatory cytokines in human fetal astrocytes. TNF-alpha and IL-1beta enhanced ICAM-1 expression at both the mRNA and protein levels, while IFN-gamma had a modest enhancing effect. However, a synergistic response was noted when IFN-gamma was added with either TNF-alpha or IL-1beta. Using human ICAM-1 deletion constructs and linker scanning mutants, we determined that the NF-kappaB element (-186 bp region) is critical for both TNF-alpha- and IL-1beta-mediated ICAM-1 expression, while the IFN-gamma activation sequence (GAS) element at -75 bp region is important for IFN-gamma stimulation. The synergistic effect between TNF-alpha and IFN-gamma is dependent on both NF-kappaB and GAS elements. Upon TNF-alpha and IL-1beta stimulation, p65 homodimers and p65/p50 heterodimers bind to the NF-kappaB site, and STAT-1alpha homodimers bind to the GAS element upon IFN-gamma stimulation. Transient transfection assays demonstrated that overexpression of the p65 protein transactivated the promoter activity of an ICAM-1 reporter construct, while p50 overexpression inhibited, in a dose-dependent manner, p65-mediated ICAM-1 expression. These data collectively suggest that in human astrocytes, the p65 homodimer is responsible for ICAM-1 upregulation upon TNF-alpha or IL-1beta stimulation, and that IFN-gamma enhancement of ICAM-1 involves activation of STAT-1alpha homodimers.

Sulfation-dependent down-regulation of interferon-gamma-induced major histocompatibility complex class I and II and intercellular adhesion molecule-1 expression on tubular and endothelial cells by glycosaminoglycans.

Previously, it has been demonstrated that heparin inhibits major histocompatibility complex (MHC) class II and intercellular adhesion molecule-1 (ICAM-1) expression on interferon-gamma (IFN-gamma)-stimulated human umbilical vein endothelial cells (HUVECs). Inasmuch as proximal tubular epithelial cells (PTECs) are prime targets in acute renal allograft rejection, we investigated whether there is a difference in the ability of heparin to influence MHC and ICAM-1 expression on PTECs as compared to HUVECs. We also studied whether the degree of sulfation of heparin is of relevance for the binding to IFN-gamma and inhibition of MHC and ICAM-1 expression after IFN-gamma stimulation. Cultured HUVECs and PTECs were stimulated with IFN-gamma for 72 hr in the presence or absence of various heparinoids. MHC and ICAM-1 expression were thereafter determined by fluorescence-activated cell sorting. Heparin was able to inhibit the up-regulation of MHC and ICAM-1 in a dose-dependent fashion on both IFN-gamma-stimulated HUVECs and PTECs. In PTEC cultures, higher concentrations of heparin were required for the inhibition of MHC class I. Heparin and supersulfated glycosaminoglycans (GAGs) were able to bind to IFN-gamma, whereas N-desulfated N-acetylated GAGs with a low amount of sulfate were not. Inhibition of cell-bound heparan sulfate proteoglycan sulfation with NaClO3 resulted in an impaired MHC and ICAM-1 expression after IFN-gamma stimulation. We postulate that IFN-gamma binds to cell-bound heparan sulfate proteoglycan in a sulfation-dependent fashion. This binding may facilitate the interaction of IFN-gamma with its receptor. Supersulfated GAGs with low anti-coagulant activity could be used therapeutically to decrease MHC and ICAM-1 expression on organ grafts.

T and B cell independence of endothelial cell adhesion molecule expression in pulmonary granulomatous inflammation.

A pulmonary Cryptococcus neoformans (Cne: strain 52D, ATCC24067) infection model in mice was used to examine the possible role for T cell-mediated immunity in regulating vascular adhesion molecules on lung endothelium during development of granulomatous inflammation. Resolution of pulmonary Cne infection in C.B-17 mice begins by Day 14 following intratracheal inoculation and depends on T cell-mediated recruitment of monocytes followed by their activation. C.B-17 scid/scid (SCID) mice mount a less exuberant pulmonary inflammatory response, recruit fewer monocytes into their lungs, and fail to clear the infection. Recruitment of leukocytes into infected tissue is mediated by both the interaction of adhesion molecules expressed on the surface of activated vascular endothelial cells with ligands on circulating cells, and the directed response of these leukocytes to chemotactic factors. The kinetics of expression of the endothelial cell adhesion molecules E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1), all previously shown to regulate monocyte recruitment, were examined in the lungs of infected C.B-17 and SCID mice during pulmonary infection to determine if T cells were necessary for their upregulation. Immunohistochemical analysis showed that upregulation of E-selectin, VCAM-1, and ICAM-1 did not differ significantly between C.B-17 and SCID mice at any time during infection. Maximal expression in C.B-17 and SCID mice was noted between Days 5 and 7 for all three molecules and preceded maximal influx of leukocytes into the lung. Thus, the inability of SCID mice to recruit optimal numbers of monocytes into infected lungs was not the result of a failure to express the critical adhesion molecules early in infection, but likely reflected absence of immune dependent chemotactic factors.

Prolonged hypoxia alters endothelial barrier function

Background: It is well recognized that hypoxia/reoxygenation and exposure to inflammatory mediators such as cytokines and neutrophils alter the barrier function of the vascular endothelium. The experiments we conducted tested whether hypoxia alone could produce changes in permeability and whether a prolonged period of hypoxia alters the surface expression of cell adhesion molecules. Methods: Endothelial cells were cultured from human umbilical vein endothelial cells (HUVECs). Hypoxia was created by isolating the cells in a chamber through which 1% O 2, 5% CO 2, and 94% N 2 were insufflated (30 min at 1 L/min). Oxygen tension was measured through oxygen-quenching phosphorescence. Hypoxia was maintained for 24 hours. Changes in endothelial permeability were measured by transendothelial electrical resistance (TEER). Endothelial leukocyte adhesion molecule 1 (ELAM-1) and intercellular adhesion molecule 1 (ICAM-1) expression were assessed by flow cytometry (mean ± standard error of the mean [SEM]). Results: Exposure of endothelial cells to hypoxia resulted in increased permeability between 6 and 24 hours, with the greatest decrease in TEER at 18 hours (63% ± 3%; P < .05). Prolonged hypoxia produced no change in the surface expression of ELAM-1 or ICAM-1. Conclusions: Hypoxia alone produced a significant reversible alteration in endothelial permeability. However, this change was observed only under severe hypoxic conditions (eg, below 20 mm Hg); higher oxygen tensions (25 and 35 mm Hg) had no significant effect. Unlike observations made after cytokine exposure, hypoxic breakdown of endothelial barrier function was unassociated with up-regulation of either ELAM-1 or ICAM-1. (Surgery 1998;124:491-7.)

High levels of soluble intercellular adhesion molecule-1 (ICAM-1) in crevicular fluid of periodontitis patients with plaque.

The intercellular adhesion molecule-1 (ICAM-1) is a membrane-bound molecule involved in cell-cell adhesive interactions which is upregulated on inflammatory epithelial cells. The levels of soluble ICAM-1 (sICAM-1) shed into the gingival crevicular fluid (GCF) were studied in healthy patients and patients with gingivitis, adult periodontitis or rapidly progressive periodontitis, using an ELISA technique. Clinical parameters including plaque index, gingival index, probing depth, and bleeding on probing were recorded following careful sampling of GCF with standardised filter strips. In GCF, sICAM-1 levels were higher for patients with plaque (p=0.04) and for patients with inflammation (p=0.02), but did not correlate with disease classifications. These results suggest that elevated GCF sICAM-1 levels may represent increased shedding of this molecule in the interstitial fluid as a result of membrane-bound ICAM-1 upregulation on ICAM-1 gingival-bearing cells in relation with plaque accumulation and inflammation.

Tumor necrosis factor up-regulates intercellular adhesion molecule 1, which is important in the neutrophil-dependent lung and liver injury associated with hepatic ischemia and reperfusion in the rat.

Tumor necrosis factor (TNF) is released during hepatic ischemia/reperfusion (I/R) and plays an important role in the ensuing neutrophil-mediated lung and liver injury. Since TNF is not a direct neutrophil chemotaxin, we hypothesized that TNF may up-regulate neutrophil adhesion molecules, specifically intercellular adhesion molecule-1 (ICAM-1), following hepatic I/R, and that this molecule then plays an important role in tissue neutrophil influx. Rats underwent 90 min of lobar hepatic ischemia with reperfusion. Pulmonary and hepatic ICAM-1 expression were assessed by reverse transcription-polymerase chain reaction, Western blot analysis, and immunohistochemical staining. Increases in hepatic ICAM-1 were demonstrated within 1 h of reperfusion, while increases in pulmonary ICAM-1 were not seen until 6 h of reperfusion. Next, rats were treated with anti-TNF antibody or control antibody without TNF neutralizing properties prior to hepatic I/R. Pretreatment with anti-TNF antibody significantly decreased pulmonary and hepatic ICAM-1 expression after hepatic I/R. We next investigated the effects of pretreatment with anti-ICAM-1 antibodies on the lung and liver injury that follows hepatic I/R. Lung injury was assessed by changes in pulmonary capillary permeability as estimated by extravasation of Evans Blue dye and pulmonary neutrophil influx as measured by lung myeloperoxidase levels. Liver injury was assessed by hepatic neutrophil morphometrics and plasma liver enzymes (alanine aminotransferase). Pretreatment with anti-ICAM-1 antibodies significantly decreased pulmonary capillary permeability, pulmonary myeloperoxidase, hepatic neutrophil influx, and plasma alanine aminotransferase, as compared to animals pretreated with control antibody. These data suggest that TNF is a proximal trigger for pulmonary and hepatic ICAM-1 up-regulation following hepatic ischemia with reperfusion, and that ICAM-1 is important for pulmonary and hepatic neutrophil influx, with the resultant tissue injury, following hepatic I/R.

Late-Onset Chronic Inflammatory Encephalopathy in Immune-Competent and Severe Combined Immune-Deficient (SCID) Mice with Astrocyte-Targeted Expression of Tumor Necrosis Factor

To examine the role of tumor necrosis factor (TNF)-alpha in the pathogenesis of degenerative disorders of the central nervous system (CNS), transgenic mice were developed in which expression of murine TNF-alpha was targeted to astrocytes using a glial fibrillary acidic protein (GFAP)-TNF-alpha fusion gene. In two independent GFAP-TNFalpha transgenic lines (termed GT-8 or GT-2) adult (>4 months of age) animals developed a progressive ataxia (GT-8) or total paralysis affecting the lower body (GT-2). Symptomatic mice had prominent meningoencephalitis (GT-8) or encephalomyelitis (GT-2) in which large numbers of B cells and CD4+ and CD8+ T cells accumulated at predominantly perivascular sites. The majority of these lymphocytes displayed a memory cell phenotype (CD44high, CD62Llow, CD25-) and expressed an early activation marker (CD69). Parenchymal lesions contained mostly CD45+ high, MHC class II+, and Mac-1+ cells of the macrophage microglial lineage with lower numbers of neutrophils and few CD4+ and CD8+ T cells. Cerebral expression of the cellular adhesion molecules ICAM-1, VCAM-1, and MAdCAM as well as a number of alpha- and beta-chemokines was induced or upregulated and preceded the development of inflammation, suggesting an important signaling role for these molecules in the CNS leukocyte migration. Degenerative changes in the CNS of the GFAP-TNFalpha mice paralleled the development of the inflammatory lesions and included primary and secondary demyelination and neurodegeneration. Disease exacerbation with more extensive inflammatory lesions that contained activated cells of the macrophage/microglial lineage occurred in GFAP-TNFalpha mice with severe combined immune deficiency. Thus, persistent astrocyte expression of murine TNF-alpha in the CNS induces a late-onset chronic inflammatory encephalopathy in which macrophage/microglial cells but not lymphocytes play a central role in mediating injury.

P38 Mitogen-activated protein kinase inhibition attenuates intercellular adhesion molecule–1 up-regulation on human pulmonary microvascular endothelial cells

Background: Increased expression of pulmonary endothelial intercellular adhesion molecule–1 (ICAM-1) is obligatory to neutrophil adherence culminating in adult respiratory distress syndrome (ARDS). The p38 mitogen-activated protein kinases (MAPKs) have been established as crucial in leukocyte proinflammatory signaling, but their role in the endothelial cell remains ill defined. We hypothesized that p38 MAPK activity is integral to ICAM-1 up-regulation on pulmonary endothelium. Methods: Human pulmonary microvascular endothelial cells (HMVECs) were grown to confluence and pretreated with either the tyrosine phophorylation inhibitor herbimycin A (1 μmol/L) or the p38 MAPK inhibitor SB203580 (10 –7 to 10 –5 mol/L) for 6 hours. ICAM-1 expression was quantified by flow cytometry. Data are expressed as mean fluorescence intensity. Western blotting was used to show p38 MAPK activity after stimulation with lipopolysaccharide (LPS) or tumor necrosis factor–α (TNF-α). Results: Tyrosine phosphorylation inhibition with herbimycin A attenuated both LPS and TNF-α stimulated ICAM-1 up-regulation. Similarly, specific inhibition of p38 MAPK attenuated both LPS (10 -6 to 10 -5 mol/L SB203580) and TNF-α (10 -7to 10 -5 mol/L SB203580) stimulated expression of ICAM-1 on HMVECs. Both LPS and TNF-α induced activation of p38 in HMVECs. Conclusions: Signaling through p38 MAPKs contributes to LPS and TNF-α stimulated ICAM-1 surface expression on HMVECs. Thus p38 MAPKs appear integral to both neutrophil and endothelial cell proinflammatory signaling and may be a potential therapeutic target in the treatment of ARDS. (Surgery 1998;124:403-8.)

P38 Mitogen-activated protein kinase inhibition attenuates intercellular adhesion molecule[ndash ]1 up-regulation on human pulmonary microvascular endothelial cells

Background: Increased expression of pulmonary endothelial intercellular adhesion molecule–1 (ICAM-1) is obligatory to neutrophil adherence culminating in adult respiratory distress syndrome (ARDS). The p38 mitogen-activated protein kinases (MAPKs) have been established as crucial in leukocyte proinflammatory signaling, but their role in the endothelial cell remains ill defined. We hypothesized that p38 MAPK activity is integral to ICAM-1 up-regulation on pulmonary endothelium. Methods: Human pulmonary microvascular endothelial cells (HMVECs) were grown to confluence and pretreated with either the tyrosine phophorylation inhibitor herbimycin A (1 μmol/L) or the p38 MAPK inhibitor SB203580 (10–7 to 10–5 mol/L) for 6 hours. ICAM-1 expression was quantified by flow cytometry. Data are expressed as mean fluorescence intensity. Western blotting was used to show p38 MAPK activity after stimulation with lipopolysaccharide (LPS) or tumor necrosis factor–α (TNF-α). Results: Tyrosine phosphorylation inhibition with herbimycin A attenuated both LPS and TNF-α stimulated ICAM-1 up-regulation. Similarly, specific inhibition of p38 MAPK attenuated both LPS (10-6 to 10-5 mol/L SB203580) and TNF-α (10-7to 10-5 mol/L SB203580) stimulated expression of ICAM-1 on HMVECs. Both LPS and TNF-α induced activation of p38 in HMVECs. Conclusions: Signaling through p38 MAPKs contributes to LPS and TNF-α stimulated ICAM-1 surface expression on HMVECs. Thus p38 MAPKs appear integral to both neutrophil and endothelial cell proinflammatory signaling and may be a potential therapeutic target in the treatment of ARDS. (Surgery 1998;124:403-8.)