Effect of Tribulus Terrestris L. on Expression of ICAM-1, VCAM-1, E-Selectin and Proteome Profile of Human Endothelial Cells In-Vitro.

BACKGROUND: Atherosclerosis is a chronic inflammation that interferes with blood arteries functions due to the accumulation of low density lipids and cholesterol. OBJECTIVE: To investigate the effect of aqueous extract and saponin fraction of Tribulus terrestris L. (TT) on the proteome and expression of intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin in the human umbilical vein endothelial cell (HUVEC) and human bone marrow endothelial cell (HBMEC) lines. METHODS: Two cell lines were cultured and induced with lipopolysaccharide (LPS). The primed cells were then treated with aqueous extract and saponin fraction of TT. The protein profile of the endothelial cells was assessed under normal and LPS-induced conditions using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and 2D gel electrophoresis (2-DE). The levels of VCAM-1, ICAM-1, and E-selectin were estimated by use of western blotting. RESULTS: LPS-induced HUVECs and HBMECs were shown to significantly increase the expression of ICAM-1, VCAM-1, and E-selectin in comparison to control groups. Our findings revealed that TT extract resulted in significantly more reduced levels of proteome (80 spots) as well as all the three mentioned proteins compared with the effect of saponin fraction alone. CONCLUSION: TT extract and its saponin fraction exerted anti-inflammatory effects on HUVEC and HBMEC lines and reduced the expression of ICAM-1, VCAM-1, and E-selectin. However, the anti-inflammatory effect of aqueous extract was greater than that of saponin fraction. Therefore, TT could be considered as a potential candidate for the treatment or prevention of atherosclerosis.

Effects of phytoestrogens derived from soy bean on expression of adhesion molecules on HUVEC.

BACKGROUND: The risks of hormone replacement therapy have led to a search for new alternatives such as phytoestrogens, plant compounds with estrogen-like biological activity. Isoflavones are the phytoestrogens most extensively studied and can be found in soybean, red clover and other plants. Due to this estrogen-like activity, phytoestrogens can have some effect on atherosclerosis. Human umbilical vein endothelial cells (HUVEC) have been extensively used to study the biology and pathobiology of human endothelial cells and most of the knowledge acquired is due to experiments with cultures of these cells. OBJECTIVE: To evaluate the effects of the phytoestrogen extracts from Glycine max soy bean, genistein, formononetin, biochanin A and daidzein, as well as a mixture of these extracts (Mix), on expression of adhesion molecules, VCAM-1, ICAM-1 and E-selectin, by endothelial cell HUVEC, stimulated with lipopolysaccharide. METHODS: HUVEC were cultured in medium EBM(2), pretreated with isoflavones for 24 and 48 h and then stimulated with lipopolysaccharide; in addition, isoflavones were added, after stimulation by lipopolysaccharide, to HUVEC. We evaluated the production of VCAM-1, ICAM-1 and E-selectin on cell surface, by cell-based enzyme immunoassay, and of sVCAM-1, sICAM-1 and sE-selectin in culture supernatant, by ELISA. RESULTS: Genistein, formononetin, biochanin A and daidzein, as well as the Mix were able to reduce VCAM-1, ICAM-1 and E-selectin on cell surface and in culture supernatant. Conclusion Isoflavones extracted from Glycine max soy bean, in vitro, presented antiatherogenic effects, reducing the expression of adhesion molecules and acting as preventive agents as well as therapeutic agents.

Nuclear factor kappaB-mediated down-regulation of adhesion molecules: possible mechanism for inhibitory activity of bigelovin against inflammatory monocytes adhesion to endothelial cells.

The flowers of Inula britannica L. var. chinensis (Rupr.) Reg. (Compositae) are used in traditional medicine to treat asthma, chronic bronchitis, and acute pleurisy in China and Korea. However, the pharmacological actions of Inula britannica L. var. chinensis on endothelial cells and inflammatory monocytes are not clear. In this study, we investigated whether bigelovin, a sesquiterpene lactone isolated from the flowers of Inula britannica L. var. chinensis, inhibits monocyte adhesion and adhesion molecule expression in brain endothelial cells. We measured tumor necrosis factor-alpha (TNF-alpha)-enhanced Raw264.7 monocyte binding to brain endothelial cells and the levels of cell adhesion molecules, including vascular adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1), and endothelial-selectin (E-selectin) on the surface of brain endothelial cells. Bigelovin significantly inhibited these in a dose-dependent manner without affecting cell viability. Furthermore, bigelovin suppressed the nuclear factor kappaB (NF-kappaB) promoter-driven luciferase activity, NF-kappaB activation, and degradation of NF-kappaB inhibitor protein alpha (IkappaBalpha). These results indicate that bigelovin inhibits inflammatory monocyte adhesion to endothelial cells and the expression of VCAM-1, ICAM-1, and E-selectin by blocking IkappaBalpha degradation and NF-kappaB activation.

Anti-inflammatory mechanisms of the Tibetan herbal preparation Padma 28 in the vessel wall.

BACKGROUND: The Tibetan herbal preparation Padma 28 has been shown to act as an anti-atherosclerotic agent in advanced peripheral arterial occlusive disease. We tested the effect of aqueous Padma 28 extracts on both the Creactive protein (CRP) induced expression of the pro-inflammatory cell adhesion molecule E-selectin and the anti-atherosclerotic protective enzyme heme oxygenase- 1 (HO-1) in human aortic endothelial cells. METHODS AND RESULTS: According to FACS analysis, quantitative RT-PCR and Western blot, CRP-induced E-selectin expression was completely prevented by aqueous Padma 28 extracts. Additionally, Padma 28 mediated an up to 60-fold upregulation of HO-1 mRNA as measured by quantitative RT-PCR. This upregulation could also be demonstrated on the protein level. CONCLUSION: Aqueous extracts of the Tibetan herbal preparation Padma 28 inhibit CRP-induced expression of the inflammatory cell adhesion molecule E-selectin and lead to upregulation of the vascular protective enzyme HO-1 in human aortic endothelial cells. These properties may be responsible for its anti-atherosclerotic effects in peripheral arterial occlusive disease.

Treatment of beta-thalassemia patients with recombinant human erythropoietin: effect on transfusion requirements and soluble adhesion molecules.

The most common single genetic disorder and a major public health issue in Greece and other Mediterranean countries is beta-thalassemia. Current therapeutic approaches for homozygous beta-thalassemia entail blood transfusions and iron chelation therapy with deferoxamine or deferiprone for preventing tissue hemosiderosis. Recently, much effort has focused on various inducers of fetal hemoglobin (HbF) such as recombinant human erythropoietin (rHuEPO), especially in beta-thalassemia intermedia. Ten adult patients, 5 with beta-thalassemia major and 5 with beta-thalassemia intermedia, received 150 IU/kg rHuEPO (epoetin-alpha) subcutaneously three times a week. Seven patients were transfused every 14-30 days and 3 with beta-thalassemia intermedia were only occasionally transfused. The minimum duration of treatment was 12 weeks in order to define if there was any response. Transfusion intervals were modified according to the rHuEPO response to maintain stable Hb values. Lower transfusion requirements were observed in 5 patients after rHuEPO treatment (p = 0.028). In the 3 non-transfused patients, Hb values increased, and the patients are still being treated and followed up for a period ranging from 14 weeks to 2 years. Two patients with thalassemia major discontinued treatment after 12 weeks, as they did not achieve any response regarding transfusion requirements or Hb values. Pretreatment serum transferrin receptor levels were higher than in controls (p < 0.001) and significantly increased following rHuEPO treatment (p = 0.027). Patients had higher serum endothelin-3, sICAM-1 and sE-selectin values before rHuEPO treatment compared to controls (p < 0.001, p < 0.001 and p = 0.016, respectively), but these values were not altered during treatment. HbF values presented a slight, non-significant increase. rHuEPO treatment has a beneficial effect in transfusion-dependent beta-thalassemia patients. Although a slight increase in HbF levels was observed, other possible mechanisms are probably involved. None of our patients experienced thrombotic complications and a rise in blood pressure.

Effects of conventional and aggressive statin treatment on markers of endothelial function and inflammation.

BACKGROUND: Atherosclerosis is considered to be a chronic inflammatory disorder. Several large-scale clinical studies demonstrate that markers of inflammation, such as high-sensitivity C-reactive protein (hsCRP), fibrinogen, and soluble CD40 ligand, are potent and independent predictors of vascular risk. HYPOTHESIS: The study was undertaken to investigate the effect of increasing the statin dose from conventional to aggressive treatment on lipids levels, inflammation, and endothelial function in patients with coronary artery disease (CAD). METHODS: We randomized 97 patients to either 20 mg simvastatin or 80 mg atorvastatin. Plasma levels of lipids, hsCRP, fibrinogen, soluble adhesion molecules, and nitric oxide-total were analyzed at baseline and after 6 months of treatment. RESULTS: Lipid values were significantly reduced in both treatment groups, but with significantly greater reduction in the aggressively treated group. Furthermore, aggressive statin treatment significantly decreased hsCRP and fibrinogen, while only small reductions were seen in the conventionally treated group, resulting in significant differences between the two treatment groups (p < 0.001). Nitric oxide-total increased significantly in both treatment groups, although the increase was more pronounced in the aggressively treated group (22.6 vs. 15.6%). CONCLUSION: Aggressive statin treatment significantly improved lipid status and reduced markers of inflammation and improved endothelial function compared with conventional treatment in patients with CAD. No interaction was observed, and high-dose treatment did not offer additional benefit compared with standard-dose treatment with respect to soluble adhesion molecules.

Delayed treatment of ischemia/reperfusion brain injury: extended therapeutic window with the proteosome inhibitor MLN519.

BACKGROUND AND PURPOSE: Clinical development of novel neuroprotection therapies for the treatment of brain injury has been unsuccessful. One critical limitation is the lack of a viable therapeutic treatment window (TW). In this study, we evaluated the neuroprotection TW for the proteosome inhibitor MLN519 after ischemia/reperfusion brain injury in rats as related to its antiinflammatory mechanism. METHODS: Male Sprague-Dawley rats were subjected to 2 hours of middle cerebral artery occlusion (MCAo), followed by 70 hours of reperfusion and recovery. MLN519 was administered after injury (starting 6 to 12 hours after MCAo) to evaluate the full TW. Brain infarction, neuronal degeneration, neurological recovery, leukocyte infiltration, and inflammatory gene mRNA levels were assessed. RESULTS: Core infarct volume in vehicle-treated rats (216+/-25 mm3) was reduced with delayed MLN519 treatments of 6, 8, or 10 hours after injury (45+/-13, 86+/-28, and 150+/-27 mm3, respectively, P<0.05) and was associated with reductions in neuronal and axonal degeneration. MLN519-treated rats had reduced brain mRNA levels of TNF-alpha (46%, P<0.05), ICAM-1 (58%, P<0.05), IL-6 (58%, P<0.05), and E-selectin (72%, P<0.05) at 24 hours after injury. Furthermore, MLN519 treatment reduced leukocyte infiltration by 32% to 80% (P<0.05) in ischemic brain regions. CONCLUSIONS: Neuroprotection treatment with MLN519 provides an extended TW of up to 10 hours after ischemia/reperfusion brain injury, in part by attenuating the inflammatory response. As such, the delayed onset of brain inflammation after an ischemic injury offers a prime target for extending the neuroprotective TW with compounds such as MLN519, used either alone or possibly as an adjunctive therapy with thrombolytic agents.

Glucocorticoid-induced differential expression of the sialylated and nonsialylated Lewis(a) epitopes and respective binding sites in human nasal polyps maintained under ex vivo tissue culture conditions.

We characterized the anti-inflammatory effects of budesonide on the expression of adhesion molecules involving Lewis(a) (Le(a)) epitope, its sialylated derivative (sLe(a)), and their respective binding sites in human nasal polyposis. By computer-assisted microscopy, we quantitatively characterized the level of histochemical expression of L- and P-selectins, sialylated and nonsialylated Le(a) epitopes, and their respective binding sites in both surface epithelium and glandular epithelium of human nasal polyps obtained from surgical resection, maintained under ex vivo tissue culture conditions for 24 hours, and treated or not with budesonide. Intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) were chosen as methodological controls, because data already published in the literature clearly indicated budesonide-mediated effects on ICAM-1 and VCAM-1 levels of expression. The present data show that budesonide significantly modified the levels of expression of ICAM-1 and VCAM-1, and to a lesser extent that of P-selectin, in the surface and glandular epithelia. Budesonide markedly decreased the levels of expression of the binding sites for both Le(a) and sLe(a), while those of Le(a) and sLe(a) remained globally unchanged. In conclusion, the present study documents that glucocorticoid-induced effects can encompass receptors for Le(a) epitopes different from E- and P-selectins on epithelial cells of human nasal polyps.

Homocysteine increases monocyte and T-cell adhesion to human aortic endothelial cells.

Although hyperhomocysteinemia has been recognized as an independent risk factor for atherosclerosis, its mechanism(s) are not well understood. Because chemotaxis and accumulation of leukocytes such as monocytes and T cells have been demonstrated to be critical events in the initiation and development of atherosclerosis, we investigated the effect of homocysteine (HCY) on U937 monocytic cells- and Jurkat T-cell-human aortic endothelial cell (HAEC) interactions under inflammatory cytokine-stimulated conditions. When HAEC were pretreated with HCY followed by stimulation with IL-1 beta, U937 and Jurkat T-cell adhesion to HAEC increased in a dose-dependent manner. The significant increase in U937 cell adhesion to HAEC was also observed when U937 cells were treated with HCY or when both cell types were treated with HCY. We also demonstrated that HCY increases endothelial surface expression and mRNA level of adhesion molecules, VCAM-1 and E-selectin. Attenuation of Jurkat T-cell and U937 cell adhesion to HAEC by monoclonal antibodies directed to specific adhesion molecules demonstrated that both VCAM-1 and E-selectin are involved in Jurkat T-cell adhesion, and VCAM-1 in U937 cell adhesion. Supplementation of HAEC with vitamin E was effective in preventing HCY-stimulated Jurkat T-cell adhesion and VCAM-1 and E-selectin expression in HAEC. These results indicate that HCY-mediated leukocyte-endothelial cell interaction is one potential mechanism by which homocysteinemia may lead to the development of atherosclerosis under inflammatory conditions. Dietary antioxidants such as vitamin E may attenuate HCY-stimulated activation of the endothelium and may help reduce the risk of vascular disease associated with hyperhomocysteinemia.

Magnolol attenuates VCAM-1 expression in vitro in TNF-alpha-treated human aortic endothelial cells and in vivo in the aorta of cholesterol-fed rabbits.

1. In a previous study, we showed that magnolol, a potent antioxidant derived from a Chinese herb, attenuates monocyte chemotactic protein-1 (MCP-1) expression and intimal hyperplasia in the balloon-injured aorta of cholesterol-fed rabbits. Expression of cell adhesion molecules by the arterial endothelium and the attachment of leukocytes to the endothelium may play a major role in atherosclerosis. In the present study, the effects of magnolol on the expression of endothelial-leukocyte adhesion molecules and the activation of nuclear factor kappa B (NF-kappa B) in tumour necrosis factor-alpha (TNF-alpha)-treated human aortic endothelial cells (HAECs) were investigated. 2. Pretreatment of HAECs with magnolol (5 microM) significantly suppressed the TNF-alpha-induced expression of vascular cell adhesion molecule-1 (VCAM-1) (64.8+/-1.9%), but had no effect on the expression of intercellular cell adhesion molecule-1 and endothelial cell selectin. 3. Magnolol (5 and 10 microM) significantly reduced the binding of the human monocytic cell line, U937, to TNF-alpha-stimulated HAECs (58.4 and 56.4% inhibition, respectively). Gel shift assays using the (32)P-labelled NF-kappa B consensus sequence as probe showed that magnolol pretreatment reduced the density of the shifted bands seen after TNF-alpha-induced activation. Immunoblot analysis and immunofluorescence staining of nuclear extracts demonstrated a 58% reduction in the amount of NF-kappa B p65 in the nuclei in magnolol-treated HAECs. Magnolol also attenuated intracellular H(2)O(2) generation in both control and TNF-alpha treated HAECs. 4. Furthermore, in vivo, magnolol attenuates the intimal thickening and TNF-alpha and VCAM-1 protein expression seen in the thoracic aortas of cholesterol-fed rabbits. 5. Taken together, these data demonstrate that magnolol inhibits TNF-alpha-induced nuclear translocation of NF-kappa B p65 and thereby suppresses expression of VCAM-1, resulting in reduced adhesion of leukocytes. These results suggest that magnolol has anti-inflammatory properties and may play important roles in the prevention of atherosclerosis and inflammatory responses in vivo.

Effects of baicalein isolated from Scutellaria baicalensis Radix on adhesion molecule expression induced by thrombin and thrombin receptor agonist peptide in cultured human umbilical vein endothelial cells.

We examined the effects of various flavonoids isolated from the roots of Scutellaria baicalensis Georgi on adhesion molecule expression induced by thrombin and thrombin receptor agonist peptide (SFLLRNPNDKYEPF, TRAP) in cultured human umbilical vein endothelial cells. Thrombin and thrombin receptor agonist peptide induced endothelial leukocyte adhesion molecule-1 (ELAM-1) expression. Intercellular adhesion molecule-1 (ICAM-1) expression was also induced by thrombin, but not by TRAP. Baicalein isolated from Scutellariae Radix inhibited ELAM-1 expression induced by thrombin and thrombin receptor agonist peptide dose-dependently, with 50% inhibitory concentrations (IC50) of 5.53 +/- 1.68 microM and 2.44 +/- 1.08 microM, respectively. Furthermore, baicalein inhibited thrombin-induced ICAM-1 expression with an IC50 of 9.67 +/- 1.28 microM. In addition, baicalein inhibited the expressions of ELAM-1 and ICAM-1 stimulated by protein kinase C (PKC) activator phorbol myristate acetate (PMA).

Synthesis and biological evaluation of a sialyl Lewis X mimic with significantly improved E-selectin inhibition.

The synthesis of the highly potent E-selectin inhibitor 5 is described. Sialyl Lewis X mimic 5 was rationally designed by combining two previously disclosed beneficial sLe(x) modifications in a single molecule. The compound was found to be 30-fold more potent than sLe(x) in a static, cell-free equilibrium assay. Furthermore, compound 5 was highly active (IC50 = 10 microM) in a dynamic non-equilibrium assay in which sLe(x) did not inhibit neutrophil rolling at up to 1000 microM.

Diarylheptanoids suppress expression of leukocyte adhesion molecules on human vascular endothelial cells.

Diarylheptanoids possess potent anti-inflammatory properties. However, the mechanism of their action is not fully understood. In this study, we found that three diarylheptanoids, 1-(3, 5-dimethoxy-4-hydroxyphenyl)-7-phenylhept-1-en-3-one (YPE-01), yakuchinone B and demethyl-yakuchinone B, reduced the adhesion of both human monocytic cell line U937 and human eosinophilic cell line EoL-1 cells to tumor necrosis factor-alpha (TNF-alpha)-treated human umbilical vein endothelial cells. In addition, they suppressed interleukin-1beta- or TNF-alpha-induced expression of E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) on the surface of the endothelial cells. Since YPE-01 reduced both VCAM-1 and ICAM-1 mRNA induction in TNF-alpha-stimulated endothelial cells, diarylheptanoids appeared to suppress adhesion molecule expression at the transcriptional level. Furthermore, YPE-01 suppressed both VCAM-1 and ICAM-1 mRNA induction as well as edema in 12-O-tetradecanoylphorbol 13-acetate (TPA)-inflamed mice ears in vivo. These results suggest that the anti-inflammatory action of diarylheptanoids is, at least in part, due to their suppressive effect on the surface expression of inducible adhesion molecules in endothelial cells, and subsequent leukocyte adhesion.

Extracts of smokeless tobacco induce pro-inflammatory changes in cultured human vascular endothelial cells.

Habitual use of smokeless tobacco leads to accumulation of inflammatory leukocytes at the site of placement, which may contribute to tissue damage. Recruitment of leukocytes is facilitated by the endothelial lining of blood vessels, which can be activated to express adhesion molecules and to produce chemoattractants. The ability of aqueous extracts of chewing tobacco, dry snuff, and moist snuff to stimulate such changes was investigated using cultured human umbilical vein endothelial cells (HUVEC). All three extracts caused HUVEC to express the adhesion molecule E-selectin and to produce the chemokines interleukin-8 and monocyte chemoattractant protein-1. Neutrophils migrated avidly across HUVEC monolayers that had been previously exposed to the extracts, whereas migration across unstimulated monolayers was negligible. The smokeless tobacco extracts contained relatively high concentrations of bacterial lipopolysaccharide (LPS). Although LPS appeared to be the major stimulatory component in extracts of chewing tobacco, it accounted for only part of the activity found in extracts of moist and dry snuffs. These observations suggest that smokeless tobacco may induce inflammatory changes in vivo by activating endothelium in a manner that promotes recruitment of leukocytes.

Effect of vitamin E on human aortic endothelial cell production of chemokines and adhesion to monocytes.

Epidemiological and clinical studies indicate that vitamin E may reduce the risk of cardiovascular disease (CVD). Modulation of adhesion molecule expression and chemokine production by vitamin E may contribute to its beneficial effect. In this study we found that the enrichment of confluent human aortic endothelial cells (HAEC) or U937 monocytic cells with increasing doses of vitamin E (d-alpha-tocopherol, 20, 40, and 60 micromol/l for 20 h) inhibited their adhesion when either or both cell types were stimulated with interleukin (IL)-1beta. Enrichment of HAEC with the same doses of vitamin E suppressed IL-1beta-stimulated expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and endothelial leukocyte adhesion molecule-1 (E-selectin). Supplementation with increasing doses of vitamin E up to 60 micromol/l was not effective in preventing spontaneous production of monocyte chemoattractant protein-1 (MCP-1), but supplementation with vitamin E at 60 micromol/l reduced IL-8 production significantly. However, IL-1beta-induced productions of both MCP-1 and IL-8 were dose-dependently suppressed by enrichment of cells with vitamin E. Vitamin E, at the doses used, did not significantly change the spontaneous production but dose-dependently inhibited the IL-1beta-induced production of inflammatory cytokine IL-6. We concluded that vitamin E could inhibit production of chemokines and inflammatory cytokines, in addition to inhibiting adhesion of HAEC to monocytes by reducing expression of adhesion molecules when cells were activated with an inflammatory cytokine. These mediators are actively involved in the pathogenesis of atherosclerosis. Therefore, their inhibition by vitamin E may contribute to vitamin E's reported reduction in risk of CVD.

Soluble P-selectin glycoprotein ligand 1 inhibits ocular inflammation in a murine model of allergy.

PURPOSE: To assess the anti-inflammatory modality of a soluble extracellular form of P-selectin glycoprotein ligand 1 (sPSGL-1) in a mouse model of ocular allergic response. METHODS: Potential anti-inflammatory effects of sPSGL-1 were investigated in SWR/J mice sensitized by topical application of short ragweed pollen to the nasal mucosa followed by a challenge of the ocular mucosa with the same allergen. Five experimental groups were included in these studies: A, mice neither sensitized nor challenged with pollen (control group 1); B, animals sensitized but not challenged (control group 2); C, animals not sensitized but challenged (control group 3); D, animals sensitized and challenged; and E, sensitized animals treated with sPSGL-1 before pollen challenge. All experimental groups were evaluated for gross morphologic ocular changes, and histologic assessments were made to determine the onset/progression of inflammatory reactions and to look for evidence of eosinophil infiltration. RESULTS: Mice sensitized and challenged with pollen developed clinical signs consistent with human allergic conjunctivitis. These signs correlate with histologic changes in the conjunctival epithelium and stroma (e.g., edema and extensive eosinophil infiltration). Moreover, the ocular changes also correlated with evidence of eosinophil degranulation. However, sensitized and challenged mice concurrently treated with sPSGL-1 displayed no inflammatory ocular changes associated with a ragweed-induced type-1 hypersensitivity reaction. The lack of ocular changes included the absence of histologic late-phase inflammatory changes of the conjunctiva and a 97% reduction in the induced eosinophil infiltrate. CONCLUSIONS: The antagonistic intervention of cell- cell interactions through the blockade of selectin-dependent leukocyte adhesion may offer novel therapeutic strategies to modulate inflammatory responses. The potent inhibitory effects on eosinophil recruitment and late-phase inflammation suggest a role for sPSGL-1 in the treatment of ocular allergic diseases.