Caffeoyl glucosides from Nandina domestica inhibit LPS-induced endothelial inflammatory responses.

Endothelial dysfunction is a key pathological feature of many inflammatory diseases, including sepsis. In the present study, a new caffeoyl glucoside (1) and two known caffeoylated compounds (2 and 3) were isolated from the fruits of Nandina domestica Thunb. (Berberidaceae). The compounds were investigated for their effects against lipopolysaccharide (LPS)-mediated endothelial inflammatory responses. At 20 µM, 1 and 2 inhibited LPS-induced hyperpermeability, adhesion, and migration of leukocytes across a human endothelial cell monolayer in a dose-dependent manner suggesting that 1 and 2 may serve as potential scaffolds for the development of therapeutic agents to treat vascular inflammatory disorders.

Rosmarinus officinalis L. essential oil inhibits in vivo and in vitro leukocyte migration.

Rosmarinus officinalis L. (Lamiaceae), popularly known as rosemary, is used for food flavoring and in folk medicine as an antispasmodic, analgesic, antirheumatic, diuretic, and antiepileptic agent. Few studies have shown the anti-inflammatory effects of rosemary essential oil (REO). This study evaluated the effects of REO on leukocyte migration through in vivo leukocyte migration and in vitro chemotaxis assay. REO was analyzed by using gas chromatography-mass spectometry, and the main components identified were camphor (27.59%), 1,8-cineole (15.74%), α-pinene (16.58%), and ß-myrcene (10.02%). In rats, administration of REO reduced the number of leukocytes that rolled, adhered, and migrated to the scrotal chamber after carrageenan injection. All doses of REO tested significantly inhibited leukocyte chemotaxis induced by casein. The effects of REO on leukocyte migration highlight an important mechanism of the anti-inflammatory action of rosemary.

Intravenous iron sucrose changes the intraperitoneal homeostasis.

BACKGROUND/AIMS: Intravenous iron infusion is the accepted way of supplementation of that compound in uremic patients. The aim of the study was to evaluate whether this treatment affects intraperitoneal homeostasis in patients on peritoneal dialysis. METHODS: Blood and peritoneal dialysate samples were collected from 10 patients treated with continuous ambulatory peritoneal dialysis who were given 100 mg iron sucrose (IS) intravenously. Systemic and peritoneal permeability as well as transperitoneal transport were studied. The effect of spent dialysate was tested in vitro on human peritoneal mesothelial cells (MCs). RESULTS: Dialysate total iron was increased (+19%, p < 0.01) during intravenous infusion of IS. Immediately after infusion the concentration of 8-OHdG was increased in plasma (+10%, p < 0.01) and in dialysate (+5%, p < 0.05). IS infusion caused a transient decrease in peritoneal permeability to protein (-42%, p < 0.05) and glucose (-30%, p < 0.01) and a reduction in dialysate cell count (-58%, p < 0.05). During the exchange dialysate hyaluronan was increased by 27% (p < 0.01). Spent dialysate, tested ex vivo on cultured MC, induced oxidative stress (+39%, p < 0.01), slowed their proliferation (-20%, p < 0.01), and stimulated MCP-1 synthesis (+46%, p < 0.01). Iron content in MCs exposed to dialysate obtained after IS infusion was increased by 32% (p < 0.01). CONCLUSION: Intravenous infusion of IS causes oxidative stress and inflammation within peritoneal MCs which may impair viability of the peritoneum.

Early laminar events involving endothelial activation in horses with black walnut- induced laminitis.

OBJECTIVE: To determine proinflammatory gene expression, endothelial adhesion molecule gene expression, and matrix metalloproteinase (MMP) concentrations in laminar specimens at 1.5 hours after administration of black walnut extract (BWE) and to compare these values with later time points. ANIMALS: 25 horses. PROCEDURES: After nasogastric administration of BWE, anesthesia was induced at 1.5 hours in early time point (ETP) horses (n = 5), between 3 and 4 hours in developmental time point horses (5), and between 9 and 10 hours in acute onset of lameness time point horses (5). Anesthesia was induced at 3 and 10 hours after nasogastric administration of water in 2 groups of control horses (3-hour control group, n = 5; 10-hour control group, 5). Real-time quantitative PCR assay was performed on laminar specimens from control and ETP horses for cyclooxygenase (COX)-1, COX-2, interleukin (IL)-1beta, tumor necrosis factor-alpha, IL-6, IL-8, IL-10, MMP-2, and MMP-9 gene expression; and on laminar specimens from all groups for endothelial adhesion molecules, intercellular adhesion molecule (ICAM)-1, and E-selectin gene expression. Leukocyte emigration was assessed via CD13 immunohistochemistry, and gelatinase accumulation was determined by gelatin zymography. RESULTS: Laminar concentrations of IL-1beta, IL-6, IL-8, COX-2, ICAM-1, and E-selectin mRNA were significantly increased in ETP horses, compared with control horses. Concentrations of IL-1beta, IL-8, ICAM-1, and E-selectin mRNA peaked at 1.5 hours. In ETP horses, leukocyte emigration was present in 3 of 5 horses and pro-MMP-9 was detected in 2 of 5 horses. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that endothelial activation and laminar inflammation are early events in laminitis; MMP accumulation likely is a downstream event.

Impact of fever-range thermal stress on lymphocyte-endothelial adhesion and lymphocyte trafficking.

The evolutionarily conserved febrile response has been associated with improved survival during infection in endothermic and ectothermic species although its protective mechanism of action is not fully understood. Temperatures within the range of physiologic fever influence multiple parameters of the immune response including lymphocyte proliferation and cytotoxic activity, neutrophil and dendritic cell migration, and production or bioactivity of proinflammatory cytokines. This review focuses on the emerging role of fever-range thermal stress in promoting lymphocyte trafficking to secondary lymphoid organs that are major sites for launching effective immune responses during infection or inflammation. Specific emphasis will be on the molecular basis of thermal control of lymphocyte-endothelial adhesion, a critical checkpoint controlling lymphocyte extravasation, as well as the contribution of interleukin-6 (IL-6) trans-signaling to thermal activities. New results are presented indicating that thermal stimulation of lymphocyte homing potential is evident in evolutionarily distant endothermic vertebrate species. These observations support the view that the evolutionarily conserved febrile response contributes to immune protection and host survival by amplifying lymphocyte access to peripheral lymphoid organs.

Vaccination with autologous endothelium inhibits angiogenesis and metastasis of colon cancer through autoimmunity.

Overcoming immune tolerance of tumor angiogenesis should be useful for adjuvant therapy of cancer. We hypothesized that vaccination with autologous endothelium would induce an autoimmune response targeting tumor angiogenesis. To test this concept, we immunized BALB/c mice with a vaccine of glutaraldehyde-fixed murine hepatic sinusoidal endothelial cells (HSEs) in a lung metastasis model of Colon-26 cancer. Vaccination with autologous HSEs induced both preventive and therapeutic anti-tumor immunity that significantly inhibited the development of metastases. ELISA revealed an immunoglobulin response involving IgM and IgG subclasses. These antibodies had a strong affinity for antigens of both murine and human endothelium, and lyzed endothelial cells in the CDC assay. Flow-cytometry and chromium-release cytotoxicity assay revealed a specific CTL response against endothelial cells, which were lyzed in an effector: target ratio-dependent manner. Neither antibodies nor CTLs reacted with Colon-26. The effect of autologous HSEs was more pronounced than that of xenogeneic human umbilical vein endothelial cells (HUVECs), which were tested in the same experimental setting. Our results suggest that vaccination with autologous endothelium can overcome peripheral tolerance of self-angiogenic antigens and therefore should be useful for adjuvant immunotherapy of cancer.

Tie2 receptor tyrosine kinase, a major mediator of tumor necrosis factor alpha-induced angiogenesis in rheumatoid arthritis.

OBJECTIVE: Rheumatoid arthritis (RA) is an inflammatory disease and an angiogenic disease. However, the molecular mechanisms promoting angiogenesis in RA are not clearly identified. Our objective was to study the role of an endothelium-specific receptor tyrosine kinase, Tie2, in angiogenesis of inflammatory arthritis. METHODS: Expression of Tie2 and its ligand, angiopoietin 1 (Ang1), in human synovium was examined by immunohistochemistry and Western blot. A novel synovium vascular window model was established to study the role of Tie2 in angiogenesis in vivo. Primary cultured endothelial cells and synoviocytes were used to study tumor necrosis factor alpha (TNF alpha)-induced Tie2 and Ang1 expression. RESULTS: Tie2 was implicated in pathologic angiogenesis. We observed that Tie2 and Ang1 were elevated in human RA synovium. Using a novel collagen-induced arthritis synovial window model, we demonstrated that Tie2 signaling regulated arthritis angiogenesis in vivo. We also showed that Tie2 mediated TNF alpha-induced angiogenesis in a mouse cornea assay. In addition, we observed that TNF alpha can regulate Tie2 activation in multiple ways that may involve interactions between endothelial cells and synoviocytes. TNF alpha up-regulates Tie2 in endothelial cells through nuclear factor kappa B, and it up-regulates Ang1 in synoviocytes. These findings suggest paracrine regulation of angiogenesis between endothelial cells and synoviocytes. CONCLUSION: This study demonstrates that Tie2 regulates angiogenesis in inflammatory synovium. Tie2 signaling is an important angiogenic mediator that links the proinflammatory cytokine TNF alpha to pathologic angiogenesis.

Vascular endothelial growth factors C and D and their VEGFR-2 and 3 receptors in blood and lymphatic vessels in healthy and arthritic synovium.

OBJECTIVE: To localize vascular endothelial growth factor C (VEGF-C) and VEGF-D in synovial specimens in relation to their VEGFR-2 and VEGFR-3 receptors in blood and lymphatic vessels. METHODS: Immunohistochemical staining and messenger RNA analysis from control and arthritic synovial membrane specimens. RESULTS: Quantitative RT-PCR disclosed that VEGF-C mRNA copy numbers were higher than VEGF-D mRNA copy numbers in the rheumatoid arthritis (RA), osteoarthritis, and control patient groups studied (p < 0.01). Immunohistochemical staining localized VEGF-C to synovial lining cell layer, pericytes, and smooth muscle cells of blood vessels. The number of VEGF-C positive cells was increased in the synovial lining of ankylosing spondylitis (AS) and RA compared to control synovium. However, in contrast to control synovial lining, little if any VEGF-D was detected in AS or RA synovial lining. VEGFR-2 expressing stromal blood vessels, also positive for the vascular endothelial marker PAL-E and the basement membrane marker laminin, were more abundant in RA and AS than in controls. Interestingly, the lymphatic endothelial receptor VEGFR-3 was also expressed in most synovial vessels, especially in the sublining capillaries and venules. CONCLUSION: VEGF-C is strongly expressed in the hypertrophic synovial lining of arthritic joints, whereas VEGF-D expression is very low in AS and RA. The expression of VEGF-C and VEGF-D in pericytes and smooth muscle cells suggests that these factors may have a role in maintaining vascular homeostasis. The VEGF receptors VEGFR-2 and VEGFR-3 are present in most of the sublining blood vessels. The expression of the lymphatic marker VEGFR-3 in the sublining blood vessels may relate to fluid filtration and/or fenestrations. The relatively few lymphatic vessels along with increased vascular permeability in RA may contribute to the development of tissue edema and joint stiffness.

Role of P-selectin and intercellular adhesion molecule-1 in TNB-induced colitis in rats.

It has been proposed that neutrophil-endothelial cell interactions mediated by adhesion molecules are involved in the pathogenesis of inflammatory bowel disease. The objective of the present study was to determine the effects of monoclonal antibodies (MAbs) directed against endothelial adhesion molecules, P-selectin and intercellular adhesion molecule-1 (ICAM-1), in rats with colitis induced by 2,4,6-trinitrobenzene sulfonic acid (TNB). Colonic inflammation was induced by administering an enema of TNB dissolved in 50% ethanol (120 mg/ml) to male Wistar rats (at a total volume of 0.25 ml per rat) after a 48-hour fast. Anti-P-selectin MAb or anti-ICAM-1 MAb was injected via the tail vein at a dose of 1 mg/kg after the induction of colitis. Rats in the control group received nonbinding mouse immunoglobulin G1. The plasma level of soluble P-selectin showed an increase within 48 h after the TNB enema. Colonic inflammation was assessed at 1 week after TNB administration. The colonic damage score and the wet weight of the colon were significantly decreased by treatment with either MAb. The increase of myeloperoxidase (MPO) activity, an index of neutrophil accumulation, and the increase of thiobarbituric acid-reactive substances (TBA-RS), an index of lipid peroxidation, in the colonic mucosa were inhibited by both MAbs. These results suggest that neutrophil-endothelial cell interactions via P-selectin and ICAM-1 play an important role in the development of TNB-induced colitis in rats.

Hypertonic saline dextran attenuates leukocyte accumulation in the liver after hemorrhagic shock and resuscitation.

BACKGROUND: Hemorrhagic shock and resuscitation triggers a global ischemia/reperfusion phenomenon, in which activated leukocytes are considered strong contributors to the ensuing tissue damage. METHODS: The aim of the study was to investigate the effects of hypertonic saline dextran (HSD) on the early leukocyte/endothelial interactions (intravital fluorescence microscopy) in a rat model of hemorrhagic shock (1 hour at mean arterial pressure of 40 mm Hg). The resuscitation was performed with lactated Ringer's solution (RL, four times shed blood/20 minutes, n = 6), 6% dextran 60 (DEX, 100% shed blood/5 minutes, n = 8), and 7.2% NaCl/10% dextran 60 (HSD, 10% shed blood/2 minutes, n = 8). RESULTS: After 1 hour of resuscitation, shock-induced stasis/adherence of leukocytes was further enhanced with RL (sinusoids 17.6+/-6.9%; venules 33.9+/-8.5%), whereas DEX and HSD attenuated leukocyte stagnation in sinusoids (DEX -7.4+/-6,1%; HSD -14.7+/-2.9%, p<0.01 vs. RL) and leukocyte adherence in postsinusoidal venules (DEX -12.2+/-8.6%, p<0.05 vs. RL; HSD -27+/-7.4%, p<0.01 vs. RL). CONCLUSION: HSD reduced significantly the number of leukocytes accumulated in the liver after resuscitation of hemorrhagic shock, probably due to a combination of mechanisms of both components.

Increased expression of HLA-DQ antigens by interstitial cells and endothelium in the synovial membrane of rheumatoid arthritis patients compared with reactive arthritis patients.

We investigated cellular phenotypes and expression of class II major histocompatibility complex antigens on endothelium and cellular infiltrates in synovium from patients with rheumatoid arthritis (RA) or reactive arthritis, using an indirect immunoperoxidase technique. The RA specimens showed synovial lining layer hypertrophy and several focal accumulations of lymphocytes, both of which were absent in the reactive arthritis synovium. The percentage of cells expressing monocyte/macrophage markers was significantly higher in RA specimens. The percentages of cells expressing B and T cell markers were similar in both diseases. There was no significant difference in the expression of HLA-DR or DP by endothelium in the 2 diseases, but a marked increase in expression of HLA-DQ by endothelium was observed in the RA synovium versus that from patients with reactive arthritis. This overexpression of HLA-DQ was also seen in the interstitial cells of RA patients compared with reactive arthritis patients. In the reactive arthritis synovium, a significant population of cells (30%) was noted to be HLA-DR positive, and negative for macrophage and lymphocyte markers. Some of these cells had a dendritic morphology. The coexpression of HLA-DQ and HLA-DR may play an important role in antigen presentation and disease chronicity in RA.

The immunopathology of acute experimental allergic encephalomyelitis. IV. An ultrastructural immunocytochemical study of class II major histocompatibility complex molecule (Ia) expression.

Cell surface expression of Class II major histocompatibility complex (Ia) molecules is required for antigen recognition by T cells. To determine the ultrastructural cellular distribution of Ia molecules in the autoimmune disease model acute experimental allergic encephalomyelitis (EAE) we studied central nervous system (CNS) tissues from adult Strain 13 guinea pigs (GP). Experimental allergic encephalomyelitis was induced by sensitization with GP spinal cord homogenate in complete Freund's adjuvant (CFA). Nine of 11 sensitized GP had clinical and histologic EAE whereas unsensitized and CFA-sensitized controls were normal. Central nervous system tissues were reacted with monoclonal antibodies to either GP Ia or T cell surface antigen using an avidin-biotin immunoperoxidase technique and studied by electron microscopy; Ia was found on luminal but not abluminal surfaces of many meningeal and parenchymal vascular endothelial cells in GP with EAE. In EAE perivascular lymphocytes and macrophages and processes of unidentified cells in the parenchyma expressed surface Ia and Ia+ macrophages encircled and phagocytosed myelin. T cells were found predominantly in perivascular inflammatory cuffs. These observations indicate that following immunologic challenge Ia is expressed on luminal surfaces of vascular endothelium and on resident CNS cells, suggesting the possibility that these cells may have active antigen-presenting functions in CNS inflammatory reactions.

Immunological consequences of ultraviolet radiation exposure.

Depending on the dose and conditions of administration, ultraviolet radiation (UVR) can function as either a complete carcinogen, a co-carcinogenic agent, or an immunologic modulator. Although much is known about its carcinogenic properties, only recently have investigations been aimed at defining the mechanisms by which UVR mediates its effect on the immune system. The objective of this article is to present the necessary background and results of recent studies that provide the basis for defining some of the local and systemic effects that UVR has on an individual's immunologic potential. This discussion focuses on: the histologic alterations in the skin and draining lymph nodes, the changes in lymphocyte localization, the increased release of the immunologic (and physiologic) mediator ETAF/IL-1, and the induction of antigen-specific immunoregulatory circuits that occur subsequent to UVR exposure. It is our hypothesis that the detrimental effects that UVR has on the host's immunologic competence may represent a normal defense mechanism to protect the individual against the adverse consequences of chronic inflammatory stimuli. In this regard, a better understanding of photoimmunology may lead to the development of more effective means of immunologic modulation for altering the clinical course of various human diseases that are either immunologically mediated, photoinduced, or responsive to phototherapy.

Acute experimental allergic encephalomyelitis in the mouse: immunopathology of the developing lesion.

To investigate the sequence of immunopathologic events during lesion formation in acute experimental allergic encephalomyelitis (EAE), SJL/J mice were inoculated with isogeneic spinal cord in complete Freund's adjuvant (CFA) and with Bordetella pertussis on Days 1 and 3 postinoculation (PI). Mice were sampled at different time points PI and T cells, T-cell subsets. Ia+ cells, Ig+ cells, albumin, and Ig deposits were localized in frozen sections by the avidin-biotin complex (ABC) method and direct fluorescence. Furthermore, samples were stained for Ia antigen, myelin basic protein (MBP), and galactocerebroside (GC) localization on endothelial cells by the ABC technique. Clinical and pathologic observations were correlated with the immunopathologic results. It was found that early in the disease process myelin and Ia-antigens were demonstrable on endothelial cells within the central nervous system (CNS). Simultaneously, damage to the blood-brain barrier was apparent, as indicated by albumin deposits, and small numbers of infiltrating T cells, T-cell subsets, and Ia+ cells were found. With time PI, the density of infiltrating total T cells (Thy-1.2+), helper/inducer (Lyt-1+), and suppressor/cytotoxic (Lyt-2+) T cells increased; Lyt-1+ and Lyt-2+ cells were detectable in meningeal as well as parenchymal infiltrates, while later on, Lyt-1+ cells showed some predilection for the CNS parenchyma and Lyt-2+ cells for meninges. Ia+ cells (B cells, macrophages, activated T cells) were present in small numbers only. Ig+ cells (B cells and macrophages) appeared shortly before onset of signs and persisted in moderate numbers. These results reconfirm the importance of early T-cell involvement for the development of EAE; they might also indicate a secondary role for Ig+ cells and are consistent with the concept that presentation of myelin antigens to T cells might occur locally on Ia-bearing endothelial cells within the CNS.