Human Peripheral Neutrophils Research Articles

Sevoflurane-induced oxidative stress and cellular injury in human peripheral polymorphonuclear neutrophils

Sevoflurane is an inhalation anesthetic used for general anesthesia. Several studies have demonstrated that reactive oxygen species (ROS) exist in cardioprotection when preconditioned with sevoflurane. Moreover, sevoflurane can also directly trigger the formation of peroxynitrite. Up to now, information pertinent to the effect of sevoflurane on cellular injuries in human polymorphonuclear neutrophils (PMN) is scant. In this study, we demonstrated that sevoflurane significantly increases intracellular H 2O 2 and/or peroxide, superoxide, and nitric oxide (NO) in PMN within 1 h treatment. Intensification of intracellular glutathione (GSH) depletion in PMN has been demonstrated with the presence of sevoflurane. Inhibition of sevoflurane-mediated intracellular H 2O 2 and/or peroxide in PMN by catalase, mannitol, dexamethasone, N-acetylcysteine (NAC) and trolox, but not superoxide dismutase (SOD) pretreatment, was observed. Among them, catalase has the best effect scavenging intracellular H 2O 2 and/or peroxide, suggesting that H 2O 2 is the major ROS during sevoflurane treatment. Two apoptotic critical factors—lowering of the mitochondrial transmembrane potential (Δ Ψ m) and activation of caspase 3/7—were significantly increased after 1 h of sevoflurane treatment. Apoptosis of PMN were determined by comet assay and flow cytometric analysis of annexin V-FITV protein binding to the cell surface. Exposure of PMN to sevoflurane markedly increased apoptosis in a dose-dependent manner. In summary, these results are important for demonstrating the oxidative stress and cellular injury on sevoflurane-treated human PMN.

Pyruvate Improves Neutrophilic Nitric Oxide Generation in Peritoneal Dialysis Solutions

To investigate the effects of pyruvate (Pyr)-based peritoneal dialysis solutions (P-PDS) on neutrophilic nitric oxide (NO) generation, we incubated human peripheral neutrophils in dL-lactate (Lac, 40 mM)-based PDS and equimolar P-PDS, and Hanks' balanced salt solution at various pH and high glucose (HG) levels, respectively. The production of NO in various test solutions was determined based on the Griess reaction. Acidic pH, high Lac, and HG induced an acute and substantial inhibition of neutrophilic NO, whereas Pyr in PDS significantly improved the NO generation in both acidic pH and physiological pH, and also in HG conditions. The Pyr protection may be associated with the improvement of glucose metabolic pathways in addition to its alkalization.

Antineutrophil cytoplasmic autoantibodies in patients with systemic lupus erythematosus recognize a novel 69 kDa target antigen of neutrophil granules

Antineutrophil cytoplasmic autoantibodies (ANCA) were found in patients with systemic lupus erythematosus (SLE). Cathepsin G and lactoferrin were the major target antigens. However, some ANCA-positive sera did not recognize either of them. The present study was to investigate the unknown target antigens of ANCA in patients with SLE and their clinical significance. Sera were collected from 72 patients with SLE. ANCA were detected in both indirect immunofluorescence and antigen-specific enzyme-linked immunosorbent assay (ELISA). Mixed neutrophil granules were separated from normal human peripheral neutrophils; soluble acid extracts in non-reducing conditions were used as antigens in western blot analysis to detect ANCA. SLE sera could blot a few bands. Interestingly, 14/72 (19.4%) sera recognized a novel 69 kDa protein band and 10/72 (13.9%) sera recognized the 55 kDa protein band, which might be bactericidal/permeability-increasing protein (BPI). The 69 kDa target antigen was different from the known target ANCA antigens such as cathepsin G and lactoferrin. Further study revealed that the percentages of patients with photosensitivity and oral ulcer in the anti-69 kDa autoantibodies-positive group were significantly higher than those in the anti-69 kDa autoantibodies-negative group (57.1%vs 10.3%, P < 0.005 and 50.0%vs 12.1%, P < 0.05, respectively). A 69 kDa protein in human neutrophil granules was identified as a novel target antigen of ANCA in patients with SLE. The anti-69 kDa autoantibodies might be associated with photosensitivity and oral ulcer in patients with SLE.

Cellular Uptake and Efflux of Azithromycin, Erythromycin, Clarithromycin, Telithromycin, and Cethromycin

Macrolide antibiotics have an outstanding ability to concentrate within host cells, particularly phagocytes. In the study described in this paper five different macrolide antibiotics were compared regarding the uptake and release kinetics in human peripheral blood polymorphonuclear neutrophils (PMNs) and three different cell lines, two phagocytic cell lines (RAW 264.7 and THP-1) and an epithelial cell line (MDCK). Based on the results obtained, the substances tested could be clustered into different groups. Azithromycin constituted the first group, characterized by rapid and nonsaturable uptake into phagocytic cells and a high degree of retention in the preloaded cells. The second group included erythromycin and clarithromycin. These two substances do not exhibit cell specificity; consequently, they are taken up to a similar extent and are released by all cell types studied. Ketolides constituted the last group. Their uptake was saturable in cells of monocytic lineage as well as in nondifferentiated cells of myeloid lineage, and they were rapidly released from all the cell lines studied. However, in PMNs, ketolide uptake was not saturable; and unlike telithromycin, cethromycin rapidly egressed from the loaded cells.

Endothelial Cells Derived from Pigs Lacking Gal??(1,3)Gal: No Reduction of Human Leukocyte Adhesion and Natural Killer Cell Cytotoxicity

The expression of galactose-alpha(1,3)galactose (Gal) on porcine cells represents a major barrier to xenotransplantation. The generation of Gal-/- pigs to overcome this barrier redirected the focus of research to other rejection mechanisms, including cellular immunity. The present in vitro study investigated (1) the adhesive interactions between human leukocyte subsets and primary endothelial cells derived from inbred Gal-/- and Gal+/+ pigs, and (2) the susceptibility of such Gal-/- porcine endothelial cells to human natural killer (NK) cell cytotoxicity. Primary porcine aortic endothelial cells (PAEC) were isolated from Gal-/- (PAEC-Gal-/-) and Gal (PAEC-Gal+/+) pigs. Human peripheral blood mononuclear cells (PBMC), polymorphonuclear neutrophils (PMN), and NK cells were isolated from healthy volunteers and tested in functional adhesion and cytotoxicity assays. Adhesion of human PBMC, PMN, or purified NK cells on PAEC-Gal-/- cells was not different from that on PAEC-Gal+/+ cells. Comparing the different leukocyte subsets of PBMC, a preferential adhesion of NK and B cells on both PAEC-Gal-/- and PAEC-Gal+/+ was detected. Tumor-necrosis factor-alpha stimulation of PAEC-Gal-/- and PAEC-Gal+/+ induced an increase of CD62E and CD106 expression and increased cellular adhesion, in particular, of PMN. The lack of Gal-/- expression on PAEC-Gal cells did not prevent xenogeneic human NK-cell cytotoxicity mediated by freshly isolated or interleukin-2-activated NK cells. Neither human leukocyte adhesion nor xenogeneic NK-cell cytotoxicity against PAEC are impaired by the lack of Gal, indicating that Gal is not a dominant target of cellular rejection.

Prevention of macrophage adhesion molecule-1 (Mac-1)-dependent neutrophil firm adhesion by taxifolin through impairment of protein kinase-dependent NADPH oxidase activation and antagonism of G protein-mediated calcium influx

Taxifolin has been reported to down-regulate the expression of intercellular adhesion molecule-1 (ICAM-1), a receptor-mediating firm adhesion with β2 integrin (e.g., Mac-1) expressed on leukocytes. To evaluate whether taxifolin could modulate Mac-1-dependent firm adhesion by neutrophils, and the possible mechanism(s) underlying its anti-inflammatory action, its effects on N-formyl-methionyl-leucyl-phenylalanine (fMLP) or phorbol-12-myristate-13-acetate (PMA)-activated peripheral human neutrophils were studied. Pretreatment with taxifolin (1–100 μM) concentration-dependently diminished fMLP- or (PMA)-induced Mac-1-dependent firm adhesion and upexpression of surface Mac-1. Mobilisation of intracellular calcium and production of reactive oxygen species (ROS) signal the upexpression of Mac-1 and firm adhesion by neutrophils. Taxifolin impeded the calcium influx induced by fMLP (a receptor-mediated activator) or AlF4− (a G protein-mediated activator). Taxifolin also effectively inhibited the fMLP- or PMA-induced ROS production with 50% inhibitory concentration (IC50) less than 10 μM, possibly through impairing the activation of NADPH oxidase, a major ROS-generating enzyme in neutrophils, by restricting the activation of p38 mitogen-activated protein kinase (p38 MAPK) and protein kinase C (PKC). In conclusion, we propose that impairment of ROS production by NADPH oxidase through interfering with p38 MAPK- and/or PKC-dependent signals, and antagonism of G protein-mediated calcium influx may account for the inhibition of Mac-1-dependent neutrophil firm adhesion that confers taxifolin the anti-inflammatory activity.

Prevention of macrophage adhesion molecule-1 (Mac-1)-dependent neutrophil firm adhesion by taxifolin through impairment of protein kinase-dependent NADPH oxidase activation and antagonism of G protein-mediated calcium influx

Taxifolin has been reported to down-regulate the expression of intercellular adhesion molecule-1 (ICAM-1), a receptor-mediating firm adhesion with β2 integrin (e.g., Mac-1) expressed on leukocytes. To evaluate whether taxifolin could modulate Mac-1-dependent firm adhesion by neutrophils, and the possible mechanism(s) underlying its anti-inflammatory action, its effects on N-formyl-methionyl-leucyl-phenylalanine (fMLP) or phorbol-12-myristate-13-acetate (PMA)-activated peripheral human neutrophils were studied. Pretreatment with taxifolin (1–100 μM) concentration-dependently diminished fMLP- or (PMA)-induced Mac-1-dependent firm adhesion and upexpression of surface Mac-1. Mobilisation of intracellular calcium and production of reactive oxygen species (ROS) signal the upexpression of Mac-1 and firm adhesion by neutrophils. Taxifolin impeded the calcium influx induced by fMLP (a receptor-mediated activator) or AlF 4 − (a G protein-mediated activator). Taxifolin also effectively inhibited the fMLP- or PMA-induced ROS production with 50% inhibitory concentration (IC 50) less than 10 μM, possibly through impairing the activation of NADPH oxidase, a major ROS-generating enzyme in neutrophils, by restricting the activation of p38 mitogen-activated protein kinase (p38 MAPK) and protein kinase C (PKC). In conclusion, we propose that impairment of ROS production by NADPH oxidase through interfering with p38 MAPK- and/or PKC-dependent signals, and antagonism of G protein-mediated calcium influx may account for the inhibition of Mac-1-dependent neutrophil firm adhesion that confers taxifolin the anti-inflammatory activity.

Evaluation of the Anti-Inflammatory Activity of Zhankuic Acids Isolated from the Fruiting Bodies ofAntrodia camphorata

We have previously shown that a concentrated ethanol extract of the fruiting bodies of Antrodia camphorata exhibited immunomodulating effects in human leukocytes and fourteen compounds including zhankuic acids A, B, C, and antcin K were identified in the extract. In this study, an acute cellular model in isolated peripheral human neutrophils was established to elucidate the anti-inflammatory effects of these compounds. Reactive oxygen species (ROS) production and firm adhesion by neutrophils display two important responses during inflammation. To evaluate whether these compounds could prevent inflammatory responses by neutrophils, their effects on N-formyl-methionyl-leucyl-phenylalanine (fMLP) or phorbol 12-myristate-13-acetate (PMA)-activated peripheral human neutrophils were examined. Pretreatment with 1 - 25 microM of zhankuic acids A, B, C, or antcin K concentration-dependently diminished fMLP- or PMA-induced ROS production, as measured by a lucigenin-amplified chemiluminescence, with IC (50) (microM) around 5 - 20 microM. Zhankuic acids A, B, C, or antcin K also effectively inhibited the fMLP- or PMA-induced firm adhesion without interfering with the up-expression of surface Mac-1 (CD11b/CD18), a beta2 integrin mediating the firm adhesion of neutrophils to endothelium. The anti-inflammatory actions of these drugs were not due to cytotoxic effects because no significant difference in cell viability was observed compared to vehicle control. These data suggest that inhibition of both ROS production and firm adhesion by neutrophils has no significant cytotoxic effect that could give these drugs the potential to be anti-inflammatory agents for the clinical treatment.

Decreased chemotaxis of human peripheral phagocytes exposed to a strong static magnetic field.

The chemotaxis of human peripheral phagocytes, neutrophils and monocytes was examined in a strong static magnetic field (0.317+/-0.012 Tesla). The chemotaxis of the suspension of purified neutrophils and monocytes was tested in the Boyden chamber using C5a as a chemotactic signal. The chambers were placed into a temperature regulated (36.6 degrees C) equipment producing a strong static magnetic field (0.317 Tesla) for 60 minutes. The movement of cells proceeded into a nitrocellulose membrane toward the north-pole of the magnet, i.e. in the direction of the Earth's gravitational pull. The C5a induced chemotaxis of human neutrophils decreased significantly in the strong static magnetic field. Monocytes were not significantly effected. The strong static magnetic field decreased the chemotactic movement of neutrophils and this phenomenon may have implications when humans are exposed to magnetic resonance imaging for extended periods of time.

Anti-inflammatory activity of the extracts from mycelia of Antrodia camphorata cultured with water-soluble fractions from five different Cinnamomum species

We have previously reported that polysaccharides extracted from fruiting bodies or cultured mycelia of Antrodia camphorata exhibit an anti-hepatitis B virus effect. In this study, we intended to elucidate the anti-inflammatory potency of six mycelial extracts, namely PDB-ext, CK-ext, CM-ext, CO-ext, CC-ext, and CKO-ext, isolated from mycelia of A. camphorata cultured with six different media including potato dextrose broth (PDB) and five water-soluble fractions from the wood of different Cinnamomum species, i.e. C. kanehirae (CK), C. micranthum (CM), C. osmophloeum (CO), C. camphora (CC), and C. kotoense (CKO), against reactive oxygen species (ROS) production induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP) or phorbol 12-myristate 13-acetate (PMA) in peripheral human neutrophils (PMN) or mononuclear cells (MNC). ROS produced by PMN or MNC act as inflammatory mediators and also signal immune responses. Pretreatment with these mycelial extracts (1–50 μg ml −1) concentration-dependently diminished fMLP- or PMA-induced ROS production in PMN or MNC, as measured by lucigenin-amplified chemiluminescence, with 50% inhibition concentrations (IC 50) ranging from 2 to 20 μg ml −1. Among these extracts evaluated, CM-ext, CO-ext, or CKO-ext exhibited higher potency than the others. Using high performance liquid chromatography, we identified two lanostane-type compounds, i.e. dehydrosulfurenic acid and 15α-acetyl-dehydrosulfurenic acid, which could be involved in the anti-inflammatory actions of these extracts. The anti-inflammatory actions of these extracts were not due to cytotoxic effects. In summary, these data suggest that extracts from cultured mycelia of A. camphorata display anti-inflammatory effects by inhibiting ROS production in human leukocytes at a pharmacologically applicable concentration. The biological activities of these extracts were further promoted when the culture medium was replaced with water-soluble fractions isolated from the wood of CM, CO or CKO.

Evaluation of the Immuno-modulating Activity of Some Active Principles Isolated from the Fruiting Bodies of Antrodia camphorata

We have previously isolated some lanostane- and ergostane-type compounds from the fruiting bodies of Antrodia camphorata and Antrodia sp. in our laboratory. In this study, an ergostane-type chemical, named antcin C (Ant C), and three lanostane-type chemicals including sulphurenic acid (SA), eburicoic acid (EA), and dehydroeburicoic acid (DeEA), were examined for their immunomodulating effect against reactive oxygen species (ROS) production induced by N-formyl-meth-ionyl-leucyl-phenylalanine (fMLP) or phorbol-1 2-myristate-1 3-acetate (PMA) in peripheral human neutrophils (PMN) or mononuclear cells (MNC). ROS production by activated-leukocytes is an important inflammatory mediator and also signals immuno-responses. Pretreatment with these four compounds concentration-dependently diminished fMLP- and PMA-induced ROS production in PMN, as measured by lucigenin-amplified chemiluminescence, with IC50 values (jiM) of 16.9±4.2, 43.9±14 and 144.8±13 for Ant C, EA and DeEA, respectively. These compounds were relatively less effective in the inhibition of ROS production by MNC with IC50 values around 200 jiM. The anti-oxidative actions of these drugs were not due to cytotoxic effects because no significant difference in cell viability was observed as compared to the vehicle control group. In summary, our data suggests that inhibition of ROS production in leukocytes by these active principles could be responsible for the immuno-modulating effects of A. camphorata.

Endotoxins of enteric pathogens are chemotactic factors for human neutrophils.

Early activation of human peripheral blood polymorphonuclear neutrophils is characterized by their morphological changes from spherical to polarized shapes. The endotoxins from enteric pathogens (S. dysenteriae type 1, V. cholerae Inaba 569B, S. typhimurium, and K. pneumoniae) were assessed by their ability to induce morphological polarization of the neutrophils as measures of early activation. Phagocytic activity, adhesion, chemokinetic locomotion, and nitroblue tetrazolium (NBT) dye-reduction ability measured the later activation of the cells. Neutrophils showed distinct morphological polarization in suspension over a wide range of concentrations of these endotoxins when were compared with those that were induced by the standard chemotactic factor, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP). It was discovered that all of the endotoxins induced locomotor responses in neutrophils in suspension that were dose- and time-dependent. The optimum concentration for the endotoxins of S. dysenteriae, V. cholerae, and K. pneumoniae was 1 mg/ml in which 71, 69, and 66% of the neutrophils were polarized. However, the S. typhimurium dose was 2 mg/ml in which 50% of the cells responded. Neutrophils that were stimulated with endotoxins also showed increased random locomotion (p<0.005) through cellulose nitrate filters, but an enhanced adhesion of the cells to glass surfaces (p<0.03). These are important functions of these cells to reach and phagocytose damaged cells, as well as invading microorganisms. Interestingly, the endotoxins had a highly-significant inhibitory effect upon the proportions of neutrophils phagocytosing opsonized yeast (p<0.01) with a small number of yeast that were engulfed by the cells (p<0.02). Further, endotoxin-treated cells showed an enhanced ability to reduce NBT dye (p<0.03). Therefore, we concluded that endotoxins of enteric pathogens are neutrophil chemotactic factors.

The Effects of Surfactant on Neutrophil Apoptosis in Lipopolysaccharide Induced Acute Lung Injury in Rat

Background : The therapeutic effects of surfactant on acute lung injury derive not only from its recruiting action on collapsed alveoli but also from its anti-inflammatory effects. Pro-apoptotic action on alveolar neutrophils represents one of the important anti-inflammatory mechanisms of surfactant. In the present study, we evaluated the effects of sufactant on the apoptosis of human peripheral and rat alveolar neutrophils. Methods : In the (Ed- the article is not definitely needed but it helps to separate the two prepositions 'in') in vitro study, human neutrophils were collected from healthy volunteers. An equal number of neutrophils () (Ed-confirm) was treated with LPS (10, 100, 1000ng/ml), surfactant (10, 100, ), or a combination of LPS (1000ng/ml) and surfactant (10, 100, ). After incubation for 24 hours, the apoptosis of neutrophils was evaluated by Annexin V method. In the in vivo study, induction of acute lung injury in SD rats by intra-tracheal instillation of LPS (5mg/kg) was followed by intra-tracheal administration of either surfactant (30mg/kg) or normal saline (5ml/kg). Tenty-four hours after LPS instillation, alveolar neutrophils were collected and the apoptotic rate was evaluated by Annexin V method. In addition, changes of the respiratory mechanics of rats (respiratory rate, tidal volume, and airway resistance) were evaluated with one chamber body plethysmography before, and 23 hours after, LPS instillation. Results : in the in vitro study, LPS treatment decreased the apoptosis of human peripheral blood neutrophils (control: , LPS 10ng/ml; , LPS 100ng/ml; , LPS 1000ng/ml; ). The combination of low to moderate doses of surfactant with LPS promoted apoptosis (LPS 1000ng/ml + Surf ; , LPS 1000ng/ml +Surf ; ). The high dose of surfactant () decreased apoptosis () and augmented the anti-apoptotic effect of LPS (LPS 1000ng/ml + Surf ; ). In the in vivo study, the apoptotic rate of alveolar neutrophils of surfactant-treated rats was higher than that of normal saline-treated rats ( vs. ). The airway resistance (represented by Penh) of surfactant-treated rats was lower than that of normal saline-treated rats at 23 hours after LPS injury ( vs. , p

Andrographolide prevents oxygen radical production by human neutrophils: possible mechanism(s) involved in its anti-inflammatory effect.

We have reported that andrographolide (ANDRO), an active component of Andrographis paniculata, inhibits inflammatory responses by rat neutrophils. To further elucidate the possible mechanism(s) underlying the ANDRO's effect, N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced adhesion and transmigration of isolated peripheral human neutrophils were studied. Pretreatment with ANDRO (0.1 - 10 microM) concentration-dependently prevented fMLP-induced neutrophil adhesion and transmigration. We further examined the up-expression of surface Mac-1 (CD11b/CD18), an essential integrin mediated in neutrophil adhesion and transmigration. ANDRO pretreatment significantly decreased fMLP-induced up-expression of both CD11b and CD18. Accumulation of reactive oxygen species (ROS) as well as quick intracellular calcium ([Ca(++)](i)) mobilization induced by fMLP displays two important signalling pathways in regulating the up-expression of Mac-1 by neutrophils. That ANDRO pretreatment diminished fMLP-induced production of H(2)O(2) and O(2)*(-), but failed to block that of [Ca(++)](i) mobilization suggested that the ROS but not [Ca(++)](i) signalling could be modulated by ANDRO. To clarify whether ROS production impeded by ANDRO could be an antagonism of fMLP binding, phorbol-12-myristate-13-acetate (PMA), a direct protein kinase C (PKC) activator, was introduced to activate ROS production. PMA triggered remarkable ROS production and adhesion, and were partially reversed by ANDRO. This indicated that a PKC-dependent mechanism might be interfered by ANDRO. We conclude that the prevention of ROS production through, at least in part, modulation of PKC-dependent pathway could confer ANDRO the ability to down-regulate Mac-1 up-expression that is essential for neutrophil adhesion and transmigration.

Effects of Diacerein on Indomethacin-Induced Gastric Ulceration

We investigated the effect of diacerein, an antiosteoarthritic agent, and its metabolite, rhein, on the production of reactive oxygen species (ROS) from neutrophils as well as the protective effect of diacerein on indomethacin-induced gastric ulceration and its protection mechanism. Rhein inhibited the ROS production from N-formyl-methionyl-leucyl-phenylalanine or phorbol-12-myristate-13-acetate-activated human peripheral neutrophils. Indomethacin-induced gastric ulceration was significantly inhibited by oxygen radical scavengers and 16,16-dimethyl-prostaglandin E₂ (dmPGE₂) but not by allopurinol. Diacerein inhibited indomethacin-induced gastric ulceration in a dose-dependent manner. Diacerein did not affect the gastric mucosal PGE₂ content. In addition, diacerein inhibited HCl + ethanol-induced gastric ulceration. These data indicate that the inhibitory effect of diacerein on indomethacin-induced gastric ulceration could be mediated not by the augmentation of gastric mucosal PGE₂ production but by the suppression of ROS production based on its inhibition of neutrophil activation.

Anti-Inflammatory Effects of the Partially Purified Extract of RadixStephaniae tetrandrae: Comparative Studies of Its Active Principles Tetrandrine and Fangchinoline on Human Polymorphonuclear Leukocyte Functions

We hypothesized that prevention of neutrophil from activation may underlie the myocardial protective effect of the specially processed extract of radix Stephaniae tetrandrae (SPRST). Inflammatory responses in isolated peripheral human neutrophils were studied in the presence or absence of SPRST. SPRST (1-10 microg/ml) concentration-dependently prevented N-formyl-methionyl-leucyl-phenylalanine (fMLP)- or leukotriene B(4) (LTB(4))-induced neutrophil adhesion and transmigration. Comparable results were also observed in neutrophils pretreated with fangchinoline (Fan) or tetrandrine (Tet), two active components in SPRST. It has been reported that neutrophil adhesion/transmigration is mainly Mac-1 (CD11b/CD18)-dependent and could be modulated by reactive oxygen species (ROS) production. SPRST, Tet, and Fan diminished fMLP- or LTB4-induced Mac-1 up-regulation and ROS production. SPRST, Fan, Tet, and verapamil impaired fMLP-induced rapid intracellular alkalization, an essential mechanism for neutrophil ROS production, and [Ca(2+)](i) increment, suggesting that a calcium dependent pathway might be involved. Direct G protein activation by AlF(4)(-) also triggered [Ca(2+)](i) increment and adhesion that could be abolished by pertussis toxin and were partially reversed by SPRST, Fan, and Tet. These results reveal that inhibition of neutrophil adhesion and transmigration may account for SPRST's myocardial protective effect. This effect of SPRST may be mediated by component(s) in addition to Tet and Fan because combination of 0.1 microg/ml of Tet and Fan did not mimic the effect of SPRST. We conclude that SPRST exerts anti-inflammatory effects by interfering with ROS production and Ca(2+) influx through G protein modulation to prevent Mac-1 up-regulation in neutrophil activation.

A role for IL-18 in neutrophil activation.

IL-18 expression and functional activity has been identified in several autoimmune and infectious diseases. To clarify the potential role of IL-18 during early innate immune responses, we have explored the capacity of IL-18 to activate neutrophils. Human peripheral blood-derived neutrophils constitutively expressed IL-18R (alpha and beta) commensurate with the capacity to rapidly respond to IL-18. IL-18 induced cytokine and chemokine release from neutrophils that was protein synthesis dependent, up-regulated CD11b expression, induced granule release, and enhanced the respiratory burst following exposure to fMLP, but had no effect upon the rate of neutrophil apoptosis. The capacity to release cytokine and chemokine was significantly enhanced in neutrophils derived from rheumatoid arthritis synovial fluid, indicating differential responsiveness to IL-18 dependent upon prior neutrophil activation in vivo. Finally, IL-18 administration promoted neutrophil accumulation in vivo, whereas IL-18 neutralization suppressed the severity of footpad inflammation following carrageenan injection. The latter was accompanied by reduction in tissue myeloperoxidase expression and suppressed local TNF-alpha production. Together, these data define a novel role for IL-18 in activating neutrophils and thereby promoting early innate immune responses.

A new mechanism for anti-inflammatory actions of proton pump inhibitors--inhibitory effects on neutrophil-endothelial cell interactions.

Neutrophil-endothelial cell interactions mediated by adhesion molecules may be involved in gastric mucosal inflammation associated with Helicobacter pylori or nonsteroidal anti-inflammatory drugs. To investigate the effects of proton pump inhibitors and histamine-2 receptor antagonists (HRA) on neutrophil-endothelial cell adhesive interactions induced by H. pylori water extract (HPE) or interleukin-1beta (IL-1beta). Human peripheral neutrophils and umbilical vein endothelial cells were incubated with either proton pump inhibitors (lansoprazole and omeprazole) or HRA (famotidine and ranitidine). Neutrophil surface expression of CD11b and CD18 and endothelial cell intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) were assessed by flow cytometry and an enzyme immunoassay, respectively. Neutrophil adherence was defined as the ratio of exogenous neutrophils that adhered to the endothelial monolayers. The expression of CD11b and CD18 on neutrophils and neutrophil-dependent adhesion to endothelial cells elicited by HPE were inhibited by lansoprazole and omeprazole at clinical relevant doses, and the expression of ICAM-1 and VCAM-1 on endothelial cells and endothelial-dependent neutrophil adherence induced by IL-1beta were also inhibited by lansoprazole and omeprazole at similar doses. Famotidine and ranitidine had no effect on neutrophil-endothelial cell interactions. These results indicate that proton pump inhibitors can attenuate neutrophil adherence to endothelial cells via inhibiting the expression of adhesion molecules, suggesting that proton pump inhibitors may have anti-inflammatory activity.

Effects of polysaccharides from Silene vulgaris on phagocytes

The effects of the polysaccharides isolated from the intact plant (pectic polysaccharides P1, P2 and P3) and from the callus (acidic arabinogalactan C1 and pectin C2) of Silene vulgaris on phagocytic activity were studied in relation to an uptaking capacity and a myeloperoxidase activity of the peripheral human neutrophils and monocytes and rat peritoneal macrophages in vitro. Both intact plant and callus polysaccharides were shown to increase uptaking capacity of peripheral phagocytes. The callus acidic arabinogalactan C1 was only found to stimulate lysosomal activity of the peripheral phagocytes. Some polysaccharides studied were established to effect on peritoneal resident macrophages. Pectins P1, P3 and C2 failed to enhance myeloperoxidase activity of the macrophages in calcium-free solution, whereas the effect of callus arabinogalactan C1 was established to be independent of extracellular calcium. Polysaccharides studied failed to influence neither complement receptor CR3- nor scavenger receptor SR-mediated adhesion of the macrophages. The data obtained demonstrate that the intact S. vulgaris and its callus may be used as sources of immunoactive polysaccharides and that pectins and weakly acidic arabinogalactan seemed to stimulate macrophages through different mechanisms. Complement receptor type 3 and scavenger receptor failed to mediate the cell activation induced by plant polysaccharides.

Effects of erythromycin on human peripheral neutrophil apoptosis

Effects of erythromycin on human peripheral neutrophil apoptosis