Serial analysis of serum and ascitic fluid levels of soluble adhesion molecules and chemokines in patients with spontaneous bacterial peritonitis

The aim of this work was the evaluation of serum and ascitic fluid levels of chemokines (IL-8, growth-regulated oncogene (Gro-alpha), and monocyte chemotactic protein-1 (MCP-1)), and of soluble adhesion molecules (P-selectin, E-selectin, L-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1)) in patients with spontaneous bacterial peritonitis (SBP). These compounds were serially analysed in serum and ascitic fluid by ELISA in patients with SBP (n = 20), non-infected cirrhotic controls (n = 12), and healthy controls (n = 15). Infected and non-infected cirrhotic patients showed significantly higher serum levels of adhesion molecules. SBP was associated with significantly higher serum and ascitic fluid levels of IL-8, Gro-alpha and ICAM-1 and with ascitic fluid concentrations of MCP-1. Significantly elevated serum levels of both ICAM-1 and VCAM-1 were detected in patient non-survivors after SBP. Thus, higher ascitic fluid levels of chemokines could be implicated in the peritoneal infiltrate in patients with SBP. Prognostic significance can be attributed to serum levels of ICAM-1 and VCAM-1 in these patients.     

Expression of adhesion molecules in synovia of patients with treatment-resistant lyme arthritis

The expression of adhesion molecules in synovium in patients with Lyme arthritis is surely critical in the control of Borrelia burgdorferi infection but may also have pathologic consequences. For example, molecular mimicry between a dominant T-cell epitope of B. burgdorferi outer surface protein A and an adhesion molecule, human lymphocyte function-associated antigen 1 (LFA-1), has been implicated in the pathogenesis of treatment-resistant Lyme arthritis. Using immunohistochemical methods, we examined synovial samples for expression of adhesion molecules in 29 patients with treatment-resistant Lyme arthritis and in 15 patients with rheumatoid arthritis or chronic inflammatory monoarthritis. In Lyme arthritis synovia, endothelial cells showed intense expression of P-selectin and vascular adhesion protein-1 (VAP-1). Expression of LFA-1 was also intense on infiltrating cells, particularly in lymphoid aggregates, and intercellular adhesion molecule-1 (ICAM-1) was markedly expressed on synovial lining and endothelial and infiltrating cells. Moderate expression of vascular cell adhesion molecule-1 (VCAM-1) was seen on synovial lining and endothelial cells, and mild expression of its ligand, very late antigen-4, was apparent in perivascular lymphoid infiltrates. Except for lesser expression of VCAM-1 in Lyme synovia, the levels of expression of these adhesion molecules were similar in the three patient groups. We conclude that certain adhesion molecules, including ICAM-1 and LFA-1, are expressed intensely in the synovia of patients with Lyme arthritis. Upregulation of LFA-1 on lymphocytes in this lesion may be critical in the pathogenesis of treatment-resistant Lyme arthritis.     

alpha 4 Integrins and sialyl Lewis x modulation in chronic Chagas disease: further evidence of persistent immune activation

We have previously shown that titers of soluble platelet selectin (s-P-selectin) and soluble vascular cell adhesion molecule-1 (s-VCAM-1) were increased in sera of patients with chronic Trypanosoma cruzi infection. In this study, we analyzed the expression of CD49d-integrins, that bind to VCAM-1, and sialyl Lewis x (SLe(x)), which binds selectins, in peripheral blood lymphocytes of 27 patients with Chagas' disease at different levels of disease severity. Patients with a mild form of Chagas' disease showed a lower number of CD49d(+) cells, in comparison with those with severe chronic cardiopathy. Decreased levels of CD49d(+) cells were detected in CD3(-) cell populations. Conversely, SLe(x) expression was found to be decreased in patients with severe Chagas' disease. Levels of soluble platelet endothelial cell adhesion molecule-1 (s-PECAM-1) were significantly increased in the plasma of patients with severe Chagas' disease while unaltered levels of MCP-1 were recorded. These data show that VCAM-1 and P-Selectin ligands are differentially expressed during the chronic phase of the Trypanosoma cruzi infection. These findings also reinforce a role of the P-selectin/SLe(x) adhesion pathway rather than very late antigen-4 (VLA-4)/VCAM-1, in the pathogenesis of Chagas' disease.     

The production of chemotactic cytokines in an allogeneic response. The role of intercellular adhesion molecule-1 and lymphocyte function-associated antigen-3.

The in vitro mixed lymphocyte reaction (MLR) is regarded as a model of responsiveness to allogeneic major histocompatibility complex antigens and has historically been used to elucidate the pathway of T lymphocyte proliferation. In addition, the MLR response may reflect activation pathways relevant in acute allograft rejection. In the present study, we have applied the MLR to examine the role of adhesion molecules intercellular adhesion molecule-1 and lymphocyte function-associated antigen-3 in the induction of tumor necrosis factor-alpha (TNF-alpha) as well as chemotactic cytokines, interleukin-8 (IL-8), monocyte chemotactic protein-1 (MCP-1) and macrophage inflammatory protein-1 alpha (MIP-1 alpha). Monoclonal antibodies to the adhesion molecules (5 micrograms/ml) were added to one-way human MLR cultures and supernatants collected at various time points. The monoclonal antibodies to the adhesion molecules significantly suppressed the proliferative response by 50 to 80%. Cytokine production, TNF-alpha (3.2 +/- 0.5 ng/ml), MIP-1 alpha (12.9 +/- 3.3 ng/ml), MCP-1 (18.8 +/- 3.4 ng/ml), and IL-8 (57 +/- 18 ng/ml) peaked on day 5 of the assay. The addition of anti-intercellular adhesion molecule-1 to the cultures suppressed TNF-alpha, MIP-1 alpha, MCP-1, and IL-8 production by 68% (1.05 +/- 0.29 ng/ml), 85% (2.0 +/- 1.2 ng/ml), 63% (6.8 +/- 2.9 ng/ml), and 47% (30.3 +/- 3.7 ng/ml), respectively. Likewise, the addition of anti-lymphocyte function-associated antigen-3 monoclonal antibody suppressed the cytokines by 78% (0.71 +/- 0.34 ng/ml), 66% (4.5 +/- 2.2 ng/ml), 52% (8.8 +/- 2.2 ng/ml), and 73% (15.7 +/- 4.4 ng/ml), respectively. Immunohistochemical staining indicated that monocytes were the primary source of the chemokines IL-8, MCP-1, and MIP-1 alpha. The addition of exogenous recombinant TNF-alpha (5 ng/ml) or recombinant IL-2 (5 units/ml) to the anti-intercellular adhesion molecule-1-treated cultures allowed the recovery of the proliferative response as well as restoration of IL-2, TNF-alpha, and IL-8, but not MCP-1 or MIP-1 alpha, indicating that both soluble and adhesion molecule signals are required for the production of the C-C family of chemokines in allogeneic responses. Thus, the events resulting in cellular proliferation and chemokine production were dependent on adhesion molecule interactions.     

Correction of defective host response to Mycobacterium bovis BCG infection in TNF-deficient mice by bone marrow transplantation

Tumour necrosis factor-alpha (TNF) plays a central role in the recruitment and activation of mononuclear cells in mycobacterial infection. In the absence of type 1 TNF receptor, Mycobacterium bovis Bacillus Calmette-Guerin (BCG) infection of mice is not contained, leading to fatal disease. Because type 1 TNF receptor binds both TNF and lymphotoxin-a, we used TNF-deficient mice to determine the specific role of TNF in the host resistance to BCG infection. The bacterial burden of the lungs of TNF-deficient mice was substantially increased and the mice succumbed to pneumonia between 8 and 12 weeks with a defective granuloma response. Atypical granulomas developed by 4 weeks expressing low levels of MHC class II, intracellular adhesion molecule (ICAM-1), CD11b and CD11c. Macrophages showed little signs of activation and had low levels of acid phosphatase activity and inducible nitric oxide synthase (INOS) expression. Despite the defective cellular recruitment, the chemokines, monocyte chemoattractant protein-1 (MCP-1) and macrophage inflammatory protein-1 (MIP-1alpha), were increased in broncho-alveolar lavage fluid of TNF-deficient mice. The defective host response was corrected by the transplantation of normal bone marrow cells into irradiated TNF-deficient mice. These results demonstrate that TNF derived from hemopoietic cells rather than from mesenchymal origin are essential for a normal host response to BCG infection. Furthermore, TNF dependent expression of adhesion molecules may be essential for the recruitment of mononuclear cells for the formation of bactericidal BCG granulomas.     

Soluble intercellular adhesion molecule-1 and E-selectin levels in plasma of falciparum malaria patients and their lack of correlation with levels of tumor necrosis factor alpha, interleukin 1 alpha (IL-1 alpha), and IL-10.

Intercellular adhesion molecule-1 and E-selectin levels were increased in the plasma of 60 falciparum malaria patients and were not related to levels of tumor necrosis factor alpha, interleukin 10, or interleukin 1 alpha. Soluble E-selectin was correlated to disease; its level in plasma was related to levels of both tumor necrosis factor soluble receptors and biological markers of disease severity and returned to baseline after parasite clearance faster than that of soluble intercellular adhesion molecule-1.     

Human cytomegalovirus infection up-regulates interleukin-8 gene expression and stimulates neutrophil transendothelial migration.

Virus-induced alterations in the cellular expression of chemokines may be important in directing the migration of specific leucocyte subsets to sites of infection, thereby playing a pivotal role in viral pathogenesis. We show here that cytomegalovirus (CMV) infection of human fibroblasts resulted in significantly increased expression of the C-X-C or alpha-chemokine interleukin-8 (IL-8), at both the mRNA and protein levels. Increased IL-8 production was seen following infection with the high passage laboratory CMV strains AD169, Towne, or Davis, as well as the low passage clinical CMV isolates Toledo or C1F. The increase in IL-8 production had functional consequences, as demonstrated by the ability of supernatants from CMV-infected fibroblasts to significantly enhance neutrophil transendothelial migration. The latter was independent of alterations in adhesion molecule expression on the endothelial cells, and was abrogated by neutralizing antibodies specific for IL-8. Direct infection of endothelium with the endothelial cell-tropic CMV strain C1FE, also resulted in enhanced neutrophil transendothelial migration. Neutrophils play an important role in the dissemination of CMV throughout the body, and thus CMV-induced neutrophil recruitment would be expected to enhance CMV dissemination. Increased production of chemokines in response to CMV infection could also disrupt the fine balance between a beneficial and a destructive immune response, thereby potentially contributing to pathology.     

Differential up-regulation of circulating soluble selectins and endothelial adhesion molecules in Sicilian patients with Boutonneuse fever.

In 150 patients with Boutonneuse fever (BF), caused by Rickettsia conorii, we studied the plasma levels of soluble L-selectin (sL-selectin), vascular cell adhesion molecule-1 (sVCAM-1), intercellular adhesion molecule-1 (sICAM-1) and E-selectin (sE-selectin) in various phases of disease to clarify their role in disease evolution. Results indicate that during the acute phase of BF there is a significant increase in the serum levels of sL-selectin, sE-selectin, sVCAM-1 and sICAM-1. sL-selectin and sVCAM-1 returned to normal levels in the third week of disease, whereas sE-selectin and sICAM-1 persisted at significantly high levels even after the third week. The secretion of these soluble CAMs in BF is mainly the result of leucocyte expression and endothelial cell activation, but secretion also appears to mediate anti-inflammatory activities, moderating leucocyte adhesion and reducing in particular lymphocyte and monocyte infiltration. Only sL-selectin serum levels were found to correlate with the acute phase of infection characterized by fever.     

Levels of macrophage inflammatory protein 1 alpha (MIP-1 alpha) and MIP-1 beta in intervillous blood plasma samples from women with placental malaria and human immunodeficiency virus infection

Macrophage inflammatory protein-1 alpha (MIP-1 alpha) and MIP-1 beta play an important role in modulating immune responses. To understand their importance in immunity to placental malaria (PM) and in human immunodeficiency virus (HIV)-PM coinfection, we investigated levels of these chemokines in the placental intervillous blood plasma (IVB plasma) and cord blood plasma of HIV-negative PM-negative, HIV-negative PM-positive, HIV-positive PM-negative, and HIV-positive PM-positive women. Compared to HIV-negative PM-negative women, the MIP-1 beta concentration in IVB plasma was significantly elevated in HIV-negative PM-positive women and HIV-positive PM-positive women, but it was unaltered in HIV-positive PM-negative women. Also, PM-infected women, irrespective of their HIV status, had significantly higher levels of MIP-1 beta than HIV-positive PM-negative women. The MIP-1 alpha level was not altered in association with either infection. The IVB plasma levels of MIP-1 alpha and MIP-1 beta positively correlated with the cord blood plasma levels of these chemokines. As with IVB plasma, only cord plasma from PM-infected mothers had significantly elevated levels of MIP-1 beta compared to PM-negative mothers, irrespective of their HIV infection status. MIP-1 beta and MIP-1 alpha levels in PM-positive women were positively associated with parasite density and malaria pigment levels. Regardless of HIV serostatus, the IVB MIP-1 beta level was significantly lower in women with PM-associated anemia. In summary, an elevated level of MIP-1 beta was associated with PM. HIV infection did not significantly alter these two chemokine levels in IVB plasma.     

Serum levels of adhesion molecules and thrombomodulin as indicators of vascular injury in severe Plasmodium falciparum malaria

Severe Plasmodium falciparum malaria is characterized by multiple organ involvment due to sequestration of infected erythrocytes in small vessels. Endothelial cell adhesion molecules play an important role in this interaction. During the course of a severe cerebral P. falciparum malaria infection we found very markedly elevated levels of the soluble adhesion molecules intercellular adhesion molecule-1, E-selectin, and vascular cell adhesion molecule-1, with a maximum increase of nine, seven, and eight times, respectively. These very high levels of soluble adhesion molecules point to an endothelial cell injury as an additional cause to physiological release or shedding due to receptor interactions. Soluble thrombomodulin (sTM) levels showed an extremely marked elevation up to 332 ng/ml (up to 13 times the normal value) as well. Malaria patients without severe organ involvement/cerebral manifestation showed only a mild elevation of sTM levels. TM is a parameter independent of the immunological system. It is regarded as a marker of vasculitis and endothelial cell destruction. Therefore, markedly elevated sTM levels document a substantial endothelial cell injury in severe malarial infection and may be of diagnostic and prognostic importance.Abbreviations VCAM-1 vascular cell adhesion molecule-1 (CD106) - ICAM-1 intercellular adhesion molecule-1 (CD54) - IL-2R interleukin-2 receptor (CD25) - TM thrombomodulin     

Extracellular superoxide dismutase attenuates lipopolysaccharide-induced neutrophilic inflammation

Extracellular superoxide dismutase (EC-SOD) is an abundant antioxidant in the lung and vascular walls. Previous studies have shown that EC-SOD attenuates lung injury in a diverse variety of lung injury models. In this study, we examined the role of EC-SOD in mediating lipopolysaccharide (LPS)-induced lung inflammation. We found that LPS-induced neutrophilic lung inflammation was exaggerated in EC-SOD-deficient mice and diminished in mice that overexpressed EC-SOD specifically in the lung. Similar patterns were seen for bronchoalveolar lavage cytokines, such as tumor necrosis factor-alpha, keratinocyte-derived chemokines, and macrophage inflammatory protein-2 as well as expression of lung intercellular adhesion molecule-1, vascular cell adhesion molecule-1, endothelial cell selectin, and platelet selectin. In a macrophage cell line, EC-SOD inhibited LPS-induced macrophage cytokine release, but did not alter expression of intercellular adhesion molecules in endothelial cells. These results suggest that EC-SOD plays an important role in attenuating the inflammatory response in the lung most likely by decreasing release of proinflammatory cytokines from phagocytes.     

Elevated levels of soluble adhesion molecules in sera of patients with acute bronchiolitis.

The mechanisms of migration of neutrophils into the airway lumen are crucial in the development of airway injury of acute bronchiolitis and are mediated by adhesion molecules. In this study, we have attempted to evaluate the role of serum concentrations of the soluble form of intercellular adhesion molecule-1 (sICAM-1) in the disease activity in acute bronchiolitis and in respiratory syncytial virus (RSV) infection. Circulating levels of sICAM-1 in sera from 10 normal control subjects, and from 47 hospitalized acute bronchiolitis patients at admission, and from 25 patients on the day of discharge were determined by use of commercially available enzyme-linked immunosorbent assay kits. The mean serum level of sICAM-1 in bronchiolitis patients was significantly higher than in the 10 healthy control infants (345.8 +/- 99.7 microg/mL vs 237.1 +/- 81.7 microg/mL; p<0.05). However, the mean sICAM-1 concentration was similar between RSV-positive and RSV-negative patients (337.5 +/- 99.6 microg/mL vs 350.9 +/- 101.1 microg/mL; p=0.65). Although the mean clinical severity score of RSV-positive patients was significantly higher than that of RSV-negative patients (5.94 +/- 1.83 vs 3.48 +/- 1.70; p<0.05). The improvement of clinical severity score was not well correlated with the change of sICAM-1 level (r=0.22). This study provides evidence that serum levels of sICAM-1 are increased in acute bronchiolitis and further confirms the role of adhesion molecules involved in the pathogenesis of the disease. However, the serum concentrations of the soluble adhesion molecules could not reliably reflect the clinical severity of the disease.     

Divalency of the monoclonal antibody 5-1-6 is required for induction of proteinuria in rats.

Leucocyte-endothelial adhesion molecules have been implicated in the pathogenesis of inflammatory diseases. To evaluate their role as markers of disease activity in tuberculosis, we have used an antigen capture ELISA to measure the serum concentrations of circulating intercellular adhesion molecule-1 (cICAM-1), E-selectin (cE-selectin) and vascular cell adhesion molecule-1 (cVCAM-1) in 34 patients with active tuberculosis (27 with pulmonary disease and seven with lymph node disease) before the commencement of standard chemotherapy, 15 subjects who had previously completed treatment for pulmonary tuberculosis, and 27 healthy volunteers. Circulating ICAM-1 and E-selectin levels were significantly elevated in patients with active tuberculosis when compared to those with treated disease (P < or = 0.01), and healthy controls (P < 0.02). Circulating VCAM-1 was raised in patients with active or old pulmonary tuberculosis (P < 0.02 versus healthy controls) but not in those with tuberculous lymphadenitis. Significant correlations were observed between the levels of cICAM-1 and cE-selectin (p = 0.63, P = 0.0001), and between cICAM-1 and cVCAM-1 (p = 0.28, P = 0.016). Taking the mean +2 s.d. of the serum level in healthy controls as the upper limit of normal range, circulating ICAM-1 had the best discriminative power in identifying active tuberculosis, being elevated in about 80% of patients but was raised in only 6.7% of subjects with treated disease and in 3.7% of normal subjects. Our data support the possibility that three adhesion molecules may be involved in the pathogenesis of tuberculosis and cICAM-1 may be a useful marker of disease activity.     

Interleukin-10 inhibits proinflammatory activation of endothelium in response to Borrelia burgdorferi or lipopolysaccharide but not interleukin-1beta or tumor necrosis factor alpha

Interleukin (IL)-10 is generally regarded as an anti-inflammatory cytokine, since it acts on a variety of cell types to suppress production of proinflammatory mediators. In inflammation, endothelial cells (EC) play a crucial role in recruiting leukocytes to sites of injury or infection. In this study, the actions of IL-10 on human umbilical vein EC were investigated. IL-10 reduced migration of monocytes and T lymphocytes across endothelium stimulated by lipopolysaccharide and decreased endothelial production of chemokines in response to lipopolysaccharide and Borrelia burgdorferi, the agent of Lyme disease. However, IL-10 did not affect these responses when EC were activated by the host proinflammatory cytokines IL-lbeta or tumor necrosis factor alpha. Moreover, IL-10 did not prevent up-regulation of the adhesion molecules E-selectin and intercellular adhesion molecule-1 by EC exposed to any of these activating agents. IL-10 therefore inhibits proinflammatory activation of EC in a manner that is selective with respect to stimulus and effector response.     

Adhesion molecule expression in Graves'' thyroid glands; potential relevance of granule membrane protein (GMP-140) and intercellular adhesion molecule-1 (ICAM-1) in the homing and antigen presentation processes.

To assess the potential role of adhesion molecules in the pathogenesis of Graves' disease, we examined the expression of several of these adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule (VCAM-1) and granule membrane protein-140 (GMP-140), in sections of Graves' thyroid glands and control thyroids, using immunohistochemical techniques. Up-regulated expression of GMP-140 was frequently observed on endothelial cells (EC) of post-capilliary venules in all Graves' thyroids examined, compared with an occasional weak staining on EC control glands. Some capillary EC around thyroid follicles (perifollicular EC) were strongly positive for GMP-140 in the Graves' thyroids in contrast to a negative staining on the same structures in the control glands. In addition, there was a correlation between the reactivity and frequency of GMP-140 expression on EC and the severity of mononuclear cell (MNC) infiltration in the Graves' thyroids. The expression of ICAM-1 was up-regulated on perifollicular EC and EC of small venules in some thyroids of both Graves' and control groups. Conversely, no significant expression was observed on any type of EC for both endothelial-leucocyte adhesion molecule-1 (ELAM-1) and VCAM-1. However, dendritic-like cells, present within lymphocytic infiltrates, were positive for VCAM-1 in most of the Graves' thyroids examined, especially in those with a severe lymphocytic infiltration. Thyrocytes were constantly negative for the expression of all four adhesion molecules investigated. These data suggest that GMP-140, as well as ICAM-1, could play an important role in the initiation of MNC infiltration in Graves' disease. ELAM-1 and VCAM-1 appear not to be relevant for the migration of MNC from the blood vessels into the target gland, although VCAM-1 expression on dendritic-like cells might play an additively tissue-selective role in autoantigen presentation and subsequent elicitation of autoimmune phenomena.     

Elevated tear fluid levels of MIP-1alpha in patients with cystic fibrosis.

Cystic fibrosis (CF) is the commonest multisystem genetic disease of white races, caused by mutations in the cystic fibrosis transmembrane regulator (CFTR), encoded on the long arm of chromosome 7. Mutations in the CFTR gene result in defective sodium, chloride, and water transport in the epithelial cells of the respiratory, hepatobiliary, gastrointestinal, and reproductive tracts, the pancreas, and the eye. The pathogenesis of ocular changes in CF is still unknown, but CF belongs to the large pathologic group of ocular surface epithelial diseases, termed keratoconjunctivitis sicca (KCS), that develop in dry eye syndrome. The aim of this study was to evaluate the levels of macrophage inflammatory protein-1alpha (MIP-1alpha) in the tear fluid of CF patients. We also investigated the correlation between the tear levels of this chemokine and clinical severity of CF and ocular surface disease. We studied 25 patients with CF with a mean age of 14 years. Chemokine levels were determined by ELISA. Complete ophthalmic examination, including dry eye tests, were used to study the ocular surface. The tear levels of MIP-1alpha in the CF patients were significantly higher when compared with healthy controls. We found a negative correlation between the tear levels of MIP-1alpha and clinical severity in CF patients and a positive correlation between the tear levels of MIP-1alpha and the presence of dry eye findings in CF patients. This current study indicates that chemokines play an important role in the ongoing inflammatory response. Our findings may help to explain one of the key factors contributing to the pathogenesis of ocular surface changes in CF patients.     

Chemokines stimulate human T lymphocyte transendothelial migration to utilize VLA-4 in addition to LFA-1

Lymphocyte infiltration in inflammation is induced by the dual actions of chemokines and cell adhesion molecules. The role of LFA-1 and VLA-4 in chemokine-induced T cell transendothelial migration (TEM) across cytokine-activated endothelium has not been examined. LFA-1, but not VLA-4, mediated blood T cell TEM to RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha), and stromal cell-derived factor-1 (SDF-1), and across tumor necrosis factor alpha (TNF-alpha) or interferon-gamma (IFN-gamma) -stimulated endothelial cells (EC). Chemokine stimulation in combination with TNF-alpha activation of EC induced TEM, which was partially mediated by VLA-4. SDF-1 increased a beta1-integrin activation epitope on T cells and enhanced VLA-4-mediated adhesion. Thus, LFA-1 mediates TEM under most conditions, but VLA-4 can also mediate TEM, although, in contrast to LFA-1, this requires exogenous chemokines and EC activation. In addition, an LFA-1- and VLA-4-independent pathway of lymphocyte TEM can also be induced by SDF-1.     

Chemokine expression in simian immunodeficiency virus-induced AIDS encephalitis.

The pathogenesis of neurological dysfunction associated with human immunodeficiency (HIV)-1 infection is uncertain. However, the presence of macrophage infiltrates in the central nervous system is a key feature of HIV encephalitis and is correlated with HIV-associated dementia. Moreover, it has been demonstrated that HIV-infected monocyte/macrophages can produce toxic substances that may play a critical role in the development of HIV-associated dementia. However, the exact mechanisms responsible for HIV infection and leukocyte recruitment to the central nervous system remain speculative. Similar to HIV-infected patients, simian immunodeficiency virus (SIV)-infected macaque monkeys develop immunosuppression and acquired immune deficiency syndrome (AIDS)-related inflammatory disorders, including AIDS encephalitis. In this study, we demonstrate that encephalitic brain from SIV-infected animals has elevated immunohistochemical expression of the C-C chemokines, macrophage inflammatory protein-1 alpha and -beta, RANTES, and monocyte chemotactic protein-3, and the C-X-C chemokine interferon-inducible protein-10. These findings suggest that one or all of of these chemokines could be involved in leukocyte recruitment to the brain in SIV-infected macaque monkeys.     

Globotriaosylceramide induces oxidative stress and up-regulates cell adhesion molecule expression in Fabry disease endothelial cells

Fabry disease, an X-linked systemic vasculopathy, is caused by a deficiency of alpha-galactosidase A resulting in globotriaosylceramide (Gb(3)) storage in cells. The pathogenic role of Gb(3) in the disease is not known. Based on previous work, we tested the hypothesis that accumulation of Gb(3) in the vascular endothelium of Fabry disease is associated with increased production of reactive oxygen species (ROS) and increased expression of cell adhesion molecules. Gb(3)-loading resulted in increased intracellular ROS production in cultured vascular endothelial cells in a dose-dependent manner. Increased Gb(3) also induced expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin. Reduction of endogenous Gb(3) by treatment of the cells with an inhibitor of glycosphingolipid synthase or alpha-galactosidase A led to decreased expression of adhesion molecules. Plasma from Fabry patients significantly increased ROS generation in endothelial cells when compared with plasma from non-Fabry controls. This effect was not influenced by reduction of intracellular Gb(3). This study provided direct evidence that excess intracellular Gb(3) induces oxidative stress and up-regulates the expression of cellular adhesion molecules in vascular endothelial cells. In addition, other factors in patient's plasma may also contribute to oxidative stress in Fabry vascular endothelial cells.