Activation Of Polymorphonuclear Neutrophils Research Articles

Neutrophil–cytokine interactions in a rat model of sulindac-induced idiosyncratic liver injury

Previous studies indicated that lipopolysaccharide (LPS) interacts with the nonsteroidal anti-inflammatory drug sulindac (SLD) to produce liver injury in rats. In the present study, the mechanism of SLD/LPS-induced liver injury was further investigated. Accumulation of polymorphonuclear neutrophils (PMNs) in the liver was greater in SLD/LPS-cotreated rats compared to those treated with SLD or LPS alone. In addition, PMN activation occurred specifically in livers of rats cotreated with SLD/LPS. The hypothesis that PMNs and proteases released from them play critical roles in the hepatotoxicity was tested. SLD/LPS-induced liver injury was attenuated by prior depletion of PMNs or by treatment with the PMN protease inhibitor, eglin C. Previous studies suggested that tumor necrosis factor-α (TNF) and the hemostatic system play critical roles in the pathogenesis of liver injury induced by SLD/LPS. TNF and plasminogen activator inhibitor-1 (PAI-1) can contribute to hepatotoxicity by affecting PMN activation and fibrin deposition. Therefore, the role of TNF and PAI-1 in PMN activation and fibrin deposition in the SLD/LPS-induced liver injury model was tested. Neutralization of TNF or inhibition of PAI-1 attenuated PMN activation. TNF had no effect on PAI-1 production or fibrin deposition. In contrast, PAI-1 contributed to fibrin deposition in livers of rats treated with SLD/LPS. In summary, PMNs, TNF and PAI-1 contribute to the liver injury induced by SLD/LPS cotreatment. TNF and PAI-1 independently contributed to PMN activation, which is critical to the pathogenesis of liver injury. Moreover, PAI-1 contributed to liver injury by promoting fibrin deposition.

Pathogenic Neisseria hitchhike on the uropod of human neutrophils.

Polymorphonuclear neutrophils (PMNs) are important components of the human innate immune system and are rapidly recruited at the site of bacterial infection. Despite the effective phagocytic activity of PMNs, Neisseria gonorrhoeae infections are characterized by high survival within PMNs. We reveal a novel type IV pilus-mediated adherence of pathogenic Neisseria to the uropod (the rear) of polarized PMNs. The direct pilus-uropod interaction was visualized by scanning electron microscopy and total internal reflection fluorescence (TIRF) microscopy. We showed that N. meningitidis adhesion to the PMN uropod depended on both pilus-associated proteins PilC1 and PilC2, while N. gonorrhoeae adhesion did not. Bacterial adhesion elicited accumulation of the complement regulator CD46, but not I-domain-containing integrins, beneath the adherent bacterial microcolony. Electrographs and live-cell imaging of PMNs suggested that bacterial adherence to the uropod is followed by internalization into PMNs via the uropod. We also present data showing that pathogenic Neisseria can hitchhike on PMNs to hide from their phagocytic activity as well as to facilitate the spread of the pathogen through the epithelial cell layer.

Boar seminal plasma or hen's egg yolk decrease the in-vitro chemotactic and phagocytotic activities of neutrophils when co-incubated with boar or bull sperm

The objective was to determine the effects of boar seminal plasma and hen's egg yolk on chemotaxis and phagocytosis of porcine and bovine polymorphonuclear neutrophils (PMNs) in vitro. Chemotactic activity of PMNs was determined following culture for 90 min in a blind well chamber. Phagocytosis was assayed after co-culture of PMNs with sperm for 60 min. In the presence of ≥ 5% boar seminal plasma, chemotactic activity of PMNs was reduced (P < 0.05) in both pigs (from 1126.1 to 934.2–1009.1 cells/mm2) and in cows (from 1067.1 to 768.9–800.0 cells/mm2). Furthermore, ≥ 5% boar seminal plasma reduced (P < 0.05) leukocyte phagocytosis in pigs (26.2–32.1%) and cows (27.2–30.0%) compared to controls (41.7 and 42.1%, respectively). Although 20% hen's egg yolk increased (P < 0.05) chemotactic activity of PMNs in pigs (from 790.4 to 1006.1 cells/mm2) and cows (from 789.9 to 953.5 cells/mm2), egg yolk increased (P < 0.05) phagocytotic activity of porcine PMNs (from 24.3 to 33.8%), but not the activity of bovine PMNs (15.1 vs 15.8% in controls). Boar seminal plasma and caffeine reduced (P < 0.05) the egg yolk-induced increase in chemotaxis in both species (from 988.6 to 795.2 or 813.2 cells/mm2 in pigs and from 953.5 to 779.4 or 833.8 cells/mm2 in cows), and phagocytotic activities of PMN (from 33.8% to 15.2 or 13.3%) only in pigs (but not in cows; 11.2–15.1%). In conclusion, hen's egg yolk increased chemotactic activity of PMNs in both pigs and cows, whereas egg yolk increased only phagocytosis of PMNs in pigs, but not in cows. Even in the presence of egg yolk, boar seminal plasma and caffeine significantly reduced chemotactic activity of PMNs in pigs and cows, and phagocytotic activity of porcine PMNs.

The Effect of Ulinastatin on Postoperative Blood Loss in Patients Undergoing Open Heart Surgery with Cardiopulmonary Bypass

This prospective, randomized, double-blind study evaluated the effect of ulinastatin on postoperative blood loss and transfusion requirements of patients undergoing open-heart surgery with cardiopulmonary bypass (CPB) and aortic cross-clamping (ACC). CPB and ACC produce variable systemic inflammatory reactions that are associated with multiorgan dysfunction via leucocytes, especially polymorphonuclear neutrophils (PMNs). PMNs increase blood loss and transfusion requirements. Ulinastatin, a urinary trypsin inhibitor, inhibits PMN activity and reduces the systemic inflammatory response. Patients received either 5000 U/kg ulinastatin or the equivalent volume of normal saline (control group) before ACC. Postoperative blood loss and transfusion requirements were recorded. Duration of intubation and length of stay in the intensive care unit (ICU) were also noted. There were no statistically significant between-group differences in postoperative blood loss and transfusion requirements. Ulinastatin caused a non-significant decrease in duration of intubation. Patients who received ulinastatin had significantly shorter ICU stays than control patients.

Hypertonic Saline Resuscitation of Hemorrhagic Shock Does Not Decrease In Vivo Neutrophil Interactions With Endothelium in the Blood-Brain Microcirculation

Resuscitation of hemorrhagic shock with isotonic crystalloids has been shown to activate polymorphonuclear neutrophils (PMNs). Although hypertonic saline (HTS) can reduce PMN activation and interactions with endothelial cells (EC) in systemic microvascular beds, no data exist demonstrating that the same occurs in the unique blood-brain barrier microcirculation. We hypothesized that resuscitation of hemorrhagic shock with HTS would blunt brain in vivo PMN-EC interactions. Wistar rats (250-350 g) underwent craniotomy and placement of a window for live intravital viewing of pial vessels. Twenty animals were bled to a mean arterial pressure of 30 mm Hg to 35 mm Hg for 1 hour and resuscitated with shed blood and either 5% HTS (6 mL/kg) or Ringer's lactate (RL) (2× shed blood volume). Circulating rhodamine-6G-labeled PMN in pial venules were captured by videomicroscopy at baseline (preshock), end of the shock period, after resuscitation, and every 15 minutes to 30 minutes for 2 hours. Hemodynamics and arterial gases were monitored. Off-line footage analysis allowed comparisons of PMN-EC interactions between groups. Animals in both groups developed significant metabolic acidosis (p < 0.01) after hemorrhage, but postresuscitation blood pressures were similar at all time points. Crystalloid resuscitation volumes were 10× greater in RL than HTS animals (p < 0.001). For all time points, we did not observe the expected reduction in PMN rolling and adhesion in HTS animals, instead noted trends of consistently lower interactions in RL counterparts. In contradistinction to studies evaluating the systemic microcirculation, HTS may activate PMN-EC crosstalk in the blood-brain microcirculation. Further studies are needed to analyze whether this effect is due to the unique nature of the blood-brain interface.

Luteolin attenuates the pulmonary inflammatory response involves abilities of antioxidation and inhibition of MAPK and NFκB pathways in mice with endotoxin-induced acute lung injury

Acute lung injury (ALI) in critically ill patients remains the leading cause of mortality and morbidity. Lipopolysaccharide (LPS) is a key mediator of lung injury. This study investigates the protective effects and mechanisms of luteolin in intratracheal instillation of LPS (100μg)-induced ALI in mice. Pretreatment of mice with 70μmol/kg luteolin significantly restores LPS-induced decrease in oxygen pressure and increase in carbon dioxide in arterial blood. The histopathological study established 70μmol/kg luteolin pretreatment markedly attenuates lung histopathological changes, such as haemorrhaging, interstitial edema, and infiltration of polymorphonuclear neutrophils (PMNs) into the lung parenchyma and alveolar spaces. Sufficient evidence for luteolin (35 and 70μmol/kg) suppresses activation and infiltration of PMNs is obtained in expression of surface marker CD11b and Ly6G on cells in bronchoalveolar lavage fluid (BALF) cells and myeloperoxidase activity in lung tissue. Furthermore, luteolin reduces the activity of catalase and superoxide dismutase, and the level of oxidative damage, and lipid peroxidation, in lung tissue. In addition, the secretion of TNF-α, KC, and ICAM-1 in the BALF after LPS challenge are also inhibited by luteolin. Moreover, luteolin reduced LPS-induced activation of MAPK and NFκB pathways. Therefore, luteolin is a potential protective antagonists for LPS-induced ALI in mice.

Effects of interferon-γ and granulocyte colony-stimulating factor on antifungal activity of human polymorphonuclear neutrophils against Candida albicans grown as biofilms or planktonic cells

Candida albicans is a leading cause of biofilm-related infections. As Candida biofilms are recalcitrant to host defenses, we sought to determine the effects of interferon-γ and granulocyte colony-stimulating factor, two pro-inflammatory cytokines, on the antifungal activities of human polymorphonuclear neutrophils (PMNs) against C. albicans biofilms, using an in vitro biofilm model. Priming of PMNs by these cytokines augmented fungal damage of planktonic cells; however, priming of PMNs did not have the same effect against Candida biofilms. Biofilm phenotype appears to play an important role in protecting C. albicans from the innate immune system.

Aberrant activation-induced cytidine deaminase expression is associated with mucosal intestinalization in the early stage of gastric cancer

Although Helicobacter pylori is a risk factor for gastric cancer (GC), its detailed carcinogenesis remains unclear. Recently, aberrant expression of activation-induced cytidine deaminase (AID) was demonstrated in gastric epithelium with H. pylori infection and seems to cause the accumulation of mutation. This investigation aims to elucidate whether or not AID expression plays an important role in the carcinogenesis of early GC. We examined the correlation between immunohistochemical AID expression and histological characteristics, including pre-existing chronic gastritis and cellular mucin phenotype in 138 cases of intramucosal GC. Furthermore, we investigated the relationship between AID, p53 protein, and β-catenin. The low degree of polymorphonuclear neutrophil activity, and the high degree of glandular atrophy and intestinal metaplasia were significantly correlated with the high levels of AID expression in non-neoplastic mucosa (P = 0.007, P ≤ 0.001, and P = 0.003). With regard to mucin phenotype of carcinoma, the intestinal phenotype tended to have the higher AID expression levels (P = 0.052). AID showed close correlations with Cdx2 and nuclear staining of β-catenin (P = 0.003, P = 0.034). As for p53 protein, no correlation was found with AID expression. Our findings suggest that aberrant AID expression is correlated with persistent inflammatory condition induced by H. pylori infection and may contribute to the development of GC through an inflammatory condition and intestinalization.

Tamm-Horsfall glycoprotein enhances PMN phagocytosis by binding to cell surface-expressed lactoferrin and cathepsin G that activates MAP kinase pathway.

The molecular basis of polymorphonuclear neutrophil (PMN) phagocytosis-enhancing activity (PEA) by human purified urinary Tamm-Horsfall glyco- protein (THP) has not been elucidated. In this study, we found human THP bound to lactoferrin (LF) and cathepsin G (CG) expressed on the surface of PMN, identified by a proteomic study with MALDI-TOF- LC/LC/mass spectrometric analysis. Pre-incubation of 10% SDS-PAGE electrophoresed PMN lysates with monoclonal anti-LF or anti-CG antibody reduced the binding with THP. To elucidate the signaling pathway of THP on PMN activation, we found THP enhanced ERK1/2 phosphorylation, reduced p38 MAP kinase phosphorylation, but had no effect on DNA binding of the five NF-κB family members in PMN. To further clarify whether the carbohydrate-side chains or protein-core structure in THP molecule is responsible for THP-PEA, THP was cleaved by different degrading enzymes with carbohydrate specificity (neuraminidase and β-galactosidase), protein specificity (V8 protease and proteinase K) or glycoconjugate specificity (carboxylpeptidase Y and O-sialoglycoprotein endopeptidase). We clearly demonstrated that the intact protein-core structure in THP molecule was more important for THP-PEA than carbohydrate-side chains. Putting these results together, we conclude that THP adheres to surface-expressed LF and CG on PMN and transduces signaling via the MAP kinase pathway to enhance PMN phagocytosis.

Polymorphonuclear neutrophils from JAK2V617F positive MPD patients do not support hypercoagulability: A study with calibrated automated thrombography (CAT)

Essential thrombocythemia and polycythemia vera are myeloproliferative disorders (MPD) with an elevated thrombotic risk. Leukocytosis has recently emerged as a new risk factor and there is increasing evidence that polymorphonuclear neutrophils (PMN) are involved. Procoagulant activity (PCA) of PMN in MPD has not yet been investigated. PCA of PMN from 22 patients with JAK2V617F positive MPD and 26 healthy subjects was studied using calibrated automated thrombography: in vitro thrombin generation induced with 1 pM tissue factor in the presence of added procoagulant phospholipids. There were no differences between patients and controls regarding the ability of PMN to increase thrombin generation. More surprisingly, basal thrombin generation in acellular MPD-plasma was found decreased for as yet unknown reasons. The presence of an active protein C pathway or platelets might provide a better insight into the coagulation phenotype in MPD.

Effects of Selectin Antagonist GMI-1070 on the Activation State of Leukocytes In Sickle Cell Patients Not In Crisis

AbstractAbstract 2672It is hypothesized that activated leukocytes play key roles in sickle cell vaso-occlusion by adhering to inflamed venules and capturing circulating platelets and sickle red blood cells. GMI-1070 is a small molecule selectin antagonist which was recently reported to reverse acute vascular occlusion in a humanized sickle cell disease (SCD) mouse model (Chang et al, Blood 2010) presumably by inhibiting E-selectin and its effects on downstream signaling of leukocyte activation. Sickle cell patients express elevated levels of soluble E-selectin (Kato et al, Brit J Haem 2005) activated polymorphonuclear neutrophils (PMN) (Lum et al Amer J Hem 2004) and platelet/monocyte aggregates (PMA) (Wun et al Clin Lab Haem 2002). In this study, the activation state of leukocytes from whole blood samples of sickle cell patients not in crisis before and after infusion of GMI-1070 was evaluated ex vivo. Isolated PMN from normal, healthy volunteers were strongly activated by binding soluble E-selectin/hIg in vitro as determined by a 7-fold increase of the integrin MAC1 (CD11b) and an 8-fold increase in expression of the high affinity form of CD18 detected by antibody 327C. Addition of GMI-1070 completely blocked upregulation of MAC1 and 327C at 50μg/ml and showed pronounced inhibition (79% MAC1; 75% 327C) at 10μg/ml. These in vitro concentrations are consistent with blood levels of GMI-1070 found in sickle cell patients 4 and 8 hours after dosing. A phase 1/2 study was conducted on 10 adult subjects with SCD at steady state. GMI-1070 was given IV at 20mg/kg as a loading dose and at 10 hours a final dose of 10mg/kg was given. Blood samples were drawn from these adults pre-infusion and at 8, 24, and 48 hours after the initial infusion. In some subjects, a blood sample was also drawn at 4 hours post infusion. Activation of PMN's in whole blood samples from subjects was assessed by upregulation of MAC-1, expression of the high affinity CD18 and the loss of CD62L due to shedding of L-selectin determined by flow cytometric analysis of cell surface labeling with fluorescently conjugated antibodies. Of 4 subjects tested, 3 showed increased surface expression of L-selectin, 3 showed decreased expression of MAC-1, and 2 showed decreased expression of high affinity CD11b at the first time point tested (4 or 8hr) after dosing with GMI-1070 suggesting an inhibition of PMN activation in these patients. A functional consequence of monocyte activation is the formation of platelet/monocyte aggregates due to expression of high affinity integrins. Platelet-monocytes aggregates (PMA) in blood were detected using anti-CD11c for monocytes and anti-CD41a for platelets. Treatment of samples with lipopolysaccharide (LPS) was used for positive controls. Intracellular IL-1β was used as a marker of activated monocytes. In 5 patients out of 6 tested with this assay, PMA in the subject's blood were decreased at the first time point after dosing (8hr). These results are consistent with an effect of GMI-1070 on inhibition of activation given its IC50 value for E-selectin (4.3μM), the blood concentration in subjects after dosing, and the serum half life (7.7hr) in steady state sickle cell adults. Conclusions:GMI-1070 significantly inhibited E-selectin-mediated activation of PMNs in vitro as determined by expression of the integrin MAC-1 and high affinity CD18 at 10μg/ml. Similar concentrations of GMI-1070 in sickle cell subjects' blood at 4 and 8 hours after dosing also resulted in a lowered activation state of PMNs identified by reduced expression of cell surface integrin molecules as well as the inhibition of shedding of L-selectin in some cases. A more functional measure of leukocyte activation is the aggregation of platelets on monocyte cell surfaces. In 5 of 6 subjects tested, GMI-1070 reduced PMA 8 hours after dosing. Thus, GMI-1070 not only inhibits E-selectin, but also blocks the expression of downstream integrin adhesion molecules that together play crucial roles in vaso-occlusion by promoting the adhesion to platelets and erythrocytes in the formation of occlusions that block blood flow. The effects of GMI-1070 on the activation state of leukocytes via the inhibition of functional adhesion molecules in steady state sickle cell subjects supports the further evaluation of treatment with GMI-1070 during vaso-occlusive episodes. Disclosures:Simon:GlycoMimetics: Research Funding. Chase:GlycoMimetics:.Kuypers:GlycoMimetics Inc.: Research Funding. Styles:GlycoMimetics: Consultancy, clinical trial sponsorship. Wun:GlycoMimetics Inc.: Consultancy, clinical trial sponsorship. Thackray:GlycoMimetics: Employment, Equity Ownership. Magnani:GlycoMimetics: Employment, Equity Ownership. Off Label Use: The drug (GMI-1070) is not approved for any clinical indication.

GLYCOCALYX PROTECTION REDUCES LEUKOCYTE ADHESION AFTER ISCHEMIA/REPERFUSION

Adhesion of polymorphonuclear neutrophils (PMN) to coronary endothelium is a key event for cardiac ischemia/reperfusion injury. Adhesion molecules are normally harbored within the glycocalyx, clothing every healthy vascular endothelium, but shed by ischemia/reperfusion. Our aim was to show whether protection of the glycocalyx with either hydrocortisone or antithrombin can reduce postischemic leukocyte adhesion. Isolated guinea pig hearts, perfused with Krebs-Henseleit buffer, were subjected to 20 min of warm (37 degrees C) no-flow ischemia and consecutive 10 min of reperfusion, either in the absence or presence of hydrocortisone (10 microg/mL) or antithrombin (1 U/mL). An intracoronary bolus of 3 x 10 PMN was applied at the end of reperfusion but without prior contact to the drugs. The sequestration of PMN was calculated from the difference between coronary input and output of cells. Expression of the integrin CD11b on PMN was measured before and after coronary passage. Ischemia/reperfusion induced severe degradation of the glycocalyx (coronary venous syndecan-1 release, 171 +/- 15 ng/g heart vs. basal, 19 +/- 2 ng/g; heparan sulfate, 5.27 +/- 0.28 microg/g vs. basal, 0.26 +/- 0.06 microg/g) and increased PMN adhesion (38.1% +/- 3.5% vs. basal, 11.7% +/- 3.1%). Hydrocortisone and antithrombin both not only reduced glycocalyx shedding (syndecan-1 release, 34 +/- 6 ng/g and 26 +/- 5 ng/g; heparan sulfate, 1.96 +/- 0.24 microg/g and 1.28 +/- 0.2 microg/g, respectively), but also PMN adhesion (17.3% +/- 2.2% and 25.4% +/- 3.3%, respectively) after ischemia/reperfusion. Electron microscopy revealed a mostly intact coronary glycocalyx after pretreatment with either drug. Activation of PMN upon coronary passage was not influenced. Preservation of the glycocalyx mitigates postischemic PMN adhesion. Preconditioning with either hydrocortisone or antithrombin should, thus, alleviate vascular leakage, tissue edema, and inflammation.

Association of variation in Fcγ receptor 3B gene copy number with rheumatoid arthritis in Caucasian samples

ObjectiveThere is increasing evidence that variation in gene copy number (CN) influences clinical phenotype. The low-affinity Fcγ receptor 3B (FCGR3B) located in the FCGR gene cluster is a CN polymorphic...

Evaluation of neutrophilic activity in patients submitted to kidney transplantation

Background: Cryoglobulinemia is frequent in renal transplant patients. The mononuclear and polymorphonuclear neutrophil (PMN) phagocytic systems are important for the clearance of cryoglobulin immune complexes. There might be a reduced phagocytic activity in transplant patients with cryoglobulinemia (CRYO+). Methods: We studied the phagocytic activity by PMNs, in the presence of immune complexes in renal transplant patients, with or without hepatitis C virus (HCV) infection. Thirty-seven patients subjected to kidney transplant were evaluated, and for the control group, healthy blood donors were chosen. The presence of cryoprecipitate was evaluated, as well as HCV infection, phagocytic activity by neutrophils during the ingestion and digestion phase. Results: The presence of cryoprecipitate was detected in 75.7% of the patients, 39.28% of which had HCV infection. IgG, IgM, IgA, and C3 and C4 complement components were identified in the cryoprecipitate. There was a reduction in the ingestion phase of phagocytosis by PMNs in renal transplant CRYO+ though the digestion phase was preserved. Conclusion: We concluded that there was a decreased PMN activity in transplanted patients presenting cryoglobulinemia.

Effects of 4-aminosalicylic acid on migration, activation and apoptosis of polymorphonuclear neutrophil in rats with experimental colitis

Objective To investigate the effects of 4-aminosalicylic acid (4-ASA) on rats with 2,4,6-trinitrobenzenesulfonic acid-induced colitis in order to understand its mechanisms in treatment of inflammatory bowel disease (IBD). Methods Thirty SD rats were given 2,4,6-trinitrobenzenesulfonic acid to induce colitis and were divided into model group, 5-ASA (200 mg/kg) treated group and 4-ASA (200 mg/kg) treated group with 10 each. Another 10 rats were severed as normal control. Seven days later,all animals were sacraficed for estimation of colonic tissues. The iNOS and serum level of interleukin (IL)-8 were detected by immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) ,respectively. And the apoptosis of polymorphonuclear neutrophil (PMN) was examined by flow cytometry. Results In comparison with model group, the body weight was increased in rats treated with 4-ASA (t= 14.09,P 0. 05). The expression of tissue iNOS was 73.55%±5.15% in model group, which was higher than that in control group [(5.95±1.45)% ,t=39.93,P<0.01)],but was lower than that in 5-ASA treated group [(37.80±3.82)%,t = 17.62,P<0.01] and 4-ASA treated group [(42.27±3.52) %, t= 15.76 ,P<0.01]. The serum level of IL-8 in model group was significantly higher than that in 5-ASA treated group and 4-ASA treated group (P<0. 01). The apoptosis of PMN in model group was lower than that in control group (t= 11.48,P<0.01), but higher than that in 5-ASA treated group (t= 7.51, P<0.01) and 4-ASA treated group (t= 10.47,P<0.01). Conclusions The efficacy of 4-ASA in treatment of IBD may be related to the mechanisms of reducing the migration and the activities of PMN, up-regulating PMN apoptosis and scavenging reactive oxygen radicals produced by PMN. Key words: Inflammatory bowel disease; p-aminosalicylic acid; Interleukin-8; Apoptosis

Neutrophils exposed to A. phagocytophilum under shear stress fail to fully activate, polarize, and transmigrate across inflamed endothelium.

Anaplasma phagocytophilum is an obligate intracellular bacterium that has evolved mechanisms to hijack polymorphonuclear neutrophil (PMN) receptors and signaling pathways to bind, infect, and multiply within the host cell. E-selectin is upregulated during inflammation and is a requisite endothelial receptor that supports PMN capture, rolling, and activation of integrin-mediated arrest. Ligands expressed by PMN that mediate binding to endothelium via E-selectin include sialyl Lewis x (sLe(x))-expressing ligands such as P-selectin glycoprotein ligand-1 (PSGL-1) and other glycolipids and glycoproteins. As A. phagocytophilum is capable of binding to sLe(x)-expressing ligands expressed on PMN, we hypothesized that acute bacterial adhesion to PMN would subsequently attenuate PMN recruitment during inflammation. We assessed the dynamics of PMN recruitment and migration under shear flow in the presence of a wild-type strain of A. phagocytophilum and compared it with a strain of bacteria that binds to PMN independent of PSGL-1. Acute bacterial engagement with PMN resulted in transient PMN arrest and minimal PMN polarization. Although the wild-type pathogen also signaled activation of beta2 integrins and elicited a mild intracellular calcium flux, downstream signals including PMN transmigration and phosphorylation of p38 mitogen-activated protein kinase (MAPK) were inhibited. The mutant strain bound less well to PMN and failed to activate beta2 integrins and induce a calcium flux but did result in decreased PMN arrest and polarization that may have been partially mediated by a suppression of p38 MAPK activation. This model suggests that A. phagocytophilum binding to PMN under shear flow during recruitment to inflamed endothelium interferes with normal tethering via E-selectin and navigational signaling of transendothelial migration.

Olprinone attenuates the development of ischemia/reperfusion injury of the gut

Splanchnic artery occlusion (SAO) shock is a severe form of circulatory shock produced by ischemia and reperfusion of the splanchnic organs. The occlusion and reperfusion of the splanchnic arteries causes activation and adhesion of polymorphonuclear neutrophils (PMNs), release of proinflammatory substances and the formation of both species of oxygen and nitrogen derivatives free radicals. Olprinone is a specific phosphodiesterase-III inhibitor that has many properties; one of which is anti-inflammatory actions at therapeutic concentrations clinically used for heart failure. In this study, we wanted to evaluate the pharmacological action of olprinone (a PDEIII inhibitor) on SAO shock in mice. SAO shock was induced by clamping both the superior mesenteric artery and the celiac trunk, resulting in a total occlusion of these arteries for 30 min. After this period of occlusion, the clamps were removed. Olprinone was given at a dose of 0.2 mg/kg i.p. 15 min before reperfusion. Our results indicated that olprinone up-regulated cAMP in injured ileum tissue, and decreased the ileum tissue damage after 1 h of reperfusion in SAO shock mice. Moreover, olprinone decreased NF-kappaB expression; the nitration of tyrosine residues; the phosphorylation of p38 MAPK and JNK; cytokine production (TNF-alpha and IL-1beta); ICAM-1 and P-selectin expression and apoptosis in the injured ileum. These results could imply a future use of olprinone in the therapy of ischemia and reperfusion shock.

Chlorogenic acid protects mice against lipopolysaccharide-induced acute lung injury

Chlorogenic acid (CGA) is one of the most abundant polyphenol compounds in human diet. Our previous in vitro study demonstrates that CGA presents anti-inflammatory activities in RAW 264.7 cells. Here we show that CGA protects mice against lipopolysaccharide (LPS)-induced acute lung injury (ALI). We treated mice with CGA (5, 20 and 50mg/kg body weight) 30min or 3h after intratracheal administration of LPS. The histological results showed that CGA, at dose of 50mg/kg, protected mice from LPS-induced ALI which displayed by edema, haemorrhage, blood vessel and alveolar structural damage. CGA inhibited LPS-increased pulmonary MPO activity and migration of polymorphonuclear neutrophils (PMNs) into bronchoalveolar lavage fluid (BALF). Furthermore, CGA markedly decreased the activity of inducible nitric oxide synthase (iNOS) in lung tissues and thus prevented nitric oxide (NO) release in response to LPS challenge. In conclusion, these results indicated that CGA was greatly effective in inhibiting ALI and might act as a potential therapeutic reagent for treating ALI in the future.

Phagocytic activity of peripheral blood and crevicular phagocytes in health and periodontal disease

Background:Neutrophils constitute the main phagocytic cell system in mammalian host defense against an infecting agent. Abnormalities in leukocyte number and function are associated with increased susceptibility to periodontal diseases. The purpose of this study is to evaluate the in vitro phagocytic properties of crevicular and peripheral blood neutrophils in healthy and periodontitis subjects.Patients and Methods:A total of 30 subjects, that is, 10 patients in each of the following three groups: healthy controls, chronic periodontitis (CP), and localized aggressive periodontitis (LAP), were included in the study. The neutrophils were isolated from the peripheral blood and gingival crevice and tested for phagocytosis of Candida albicans. The percentage of leukocytes with ingested C. albicans was determined by light microscopy.Results:A significant reduction in the phagocytic activity of crevicular fluid polymorphonuclear neutrophils (CF-PMN) of LAP subjects (mean: 54.3±7)(P<0.001) was observed, compared to healthy controls (mean: 74.2±9) and chronic periodontitis subjects (mean: 69±9)(P=0.352). The mean percentage of peripheral blood polymorphonuclear neutrophils (PMNs) with phagocytosis of opsonized C. albicans in LAP patients was significantly reduced (mean: 74.9±5)(P<0.0068) compared to the phagocytic activity of neutrophils from controls (mean:82.1±3) and chronic periodontitis subjects (mean: 82.0±5)(P=0.970). There was no significant reduction in the phagocytic activity of CF PMNs (mean: 69±9) (P=0.35) and peripheral blood PMNs (mean: 82.5)(P=0.97) in the chronic periodontitis group when compared to the control group.Conclusion:The phagocytic activity of both crevicular and peripheral neutrophils in subjects with periodontitis is altered, increasing the susceptibility to periodontitis. Thus individual susceptibility may be an additional and important modifying factor in the pathogenesis of periodontal disease.

The effect of zinc on hydroxyapatite-mediated activation of human polymorphonuclear neutrophils and bone implant-associated acute inflammation

Hydroxyapatite (HA) is widely used as coating biomaterial for prosthesis metal parts and as bone substitute. The release of HA particles induces an inflammatory response and, if uncontrolled, could result in implant loss. At the inflamed site, the polymorphonuclear cells (PMNs) represent the earliest phagocytic cells that predominate the cellular infiltrate. We have recently proposed that HA wear debris activate polymorphonuclear cells (PMNs) initiating and/or amplifying thereby the acute inflammatory response. Previous studies have shown that activation of monocytes by HA could be modulated by supplementing this latter with the divalent cation, Zinc. The purpose of this work was to investigate the modulation of PMNs activation following exposure to zinc-substituted HA. Our study demonstrate that addition of zinc to HA particles resulted in decreased levels of the pro-inflammatory mediator interleukin-8 (IL-8) and the matrix metallo-proteinase-9. We also show that these changes involve IL-8 receptors (CXCR-1 and CXCR-2).