Clinical association between chronic periodontitis and the leukocyte extravasation inhibitors developmental endothelial locus‐1 and pentraxin‐3

This clinical study aimed to determine whether periodontal disease is associated with expression of developmental endothelial locus‐1 (Del‐1) and pentraxin‐3 (PTX‐3), endogenous inhibitors of leukocyte extravasation in humans. Expression of DEL1, PTX3, interleukin‐17A (IL17A), and lymphocyte function‐associated antigen‐1 (LFA1) was determined, using RT‐PCR and melting curve analysis, in biopsies of gingival tissues from 95 patients: 42 with moderate periodontitis; 40 with severe periodontitis; and 13 healthy controls. Relative expression of DEL1 and PTX3 was statistically significantly weaker in patients with periodontitis than in the control subjects. On the contrary, both IL17A and LFA1 showed statistically significant stronger expression in patients with periodontitis than in healthy controls. Correlation analysis, performed using Spearman's test, showed that expression of DEL1 was statistically significantly linked to periodontitis (ρ = ?0.103) and to age (ρ = ?0.134), but not to the gender of the patient, and that expression of PTX3 was significantly correlated with periodontitis (ρ = ?0.354). Expression of neutrophil extravasation inhibitors DEL1 and PTX3 show significant, but weak, association with the clinical manifestation of chronic periodontitis.     

The pro-inflammatory role of platelets in cancer

Thrombosis is a frequent issue in cancer patients. Tumor-induced platelet activation and coagulation does not only constitute a significant risk for thrombosis, but also contribute to tumor progression by promoting critical processes such as angiogenesis and metastasis. In addition to their role in hemostasis, platelets are increasingly recognized as regulators of inflammation. By modulating the immune system, platelets regulate several aspects of cancer-associated pathology. Platelets influence the inflammatory response in cancer by affecting the activation status of the endothelium and by recruiting leukocytes to primary and metastatic tumor sites, as well as to distant organs unaffected by tumor growth. Furthermore, platelets participate in the formation of neutrophil extracellular traps, which can promote metastasis, thrombosis, and contribute to organ failure. In this review, we discuss the role of platelets as coordinators of the immune system during malignant disease and the potential of targeting platelets to prevent cancer-associated pathology.     

Entamoeba histolytica induces human neutrophils to form NETs

Entamoeba histolytica invades the intestine and other organs during the pathogenesis of amoebiasis. In the early stages, the host organism responds with an inflammatory infiltrate composed mostly of neutrophils. It has been reported that these immune cells, activated by E. histolytica, exert a protective role by releasing proteolytic enzymes and generating reactive oxygen/nitrogen species (ROS/RNS) and antimicrobial peptides. It is now known that neutrophils also produce neutrophil extracellular traps (NETs), which are able to damage and kill pathogens. Studies have shown that intracellular protozoan pathogens, including Toxoplasma gondi, Plasmodium falciparum and Leishmania spp, induce neutrophils to release NETs and are damaged by them. However, the action of this mechanism has not been explored in relation to E. histolytica trophozoites. Through scanning electron, epifluorescence microscopy and viability assays, we show for first time that during in vitro interaction with E. histolytica trophozoites, human neutrophils released NETs that covered amoebas and reduced amoebic viability. These NETs presented histones, myeloperoxidase and decondensed chromatin. The results suggest that NETs participate in the elimination of the parasite.     

黄连解毒汤含药血清对LPSTNF-α诱导的人中性粒细胞与血管内皮细胞间粘附的影响

以体外培养的人脐静脉内皮细胞（HUVEC）为模型,应用蛋白染料染色法,观察HLJDT含药血清及其与LPS／TNF－α共同处理HUVEC4h、12h、24h后,对中性粒细胞与血管内皮细胞粘附的影响。结果显示,HLJDT含药血清不仅能抑制非致炎状态下中性粒细胞与血管内皮细胞的粘附,而且能抑制致炎因子所诱导的中性粒细胞与血管内皮细胞粘附作用增强,这可能是黄连解毒汤抗炎作用的机制之一。     

Respiratory syncytial virus and neutrophil activation

Respiratory syncytial virus infects almost all children by 2 years of age. Neutrophils are the predominant airway leucocytes in RSV bronchiolitis and they are activated in the presence of infection. However it is not clear whether RSV can directly signal to activate neutrophil cytotoxic function. To investigate this we have used a preparation of RSV washed using a new centrifugal diafiltration method to rapidly remove inflammatory molecules produced by the epithelial cells used to propagate the RSV stock. Human neutrophils were isolated from peripheral blood and activated with either the unwashed crude RSV preparations or the purified intact RSV. Neutrophils were also challenged with purified RSV G-glycoprotein. The effect of challenging human neutrophils with these preparations of intact RSV, or the RSV G-glycoprotein, was assessed by measuring the cell surface expression of CD11b and CD18b, the phagocytic oxidative burst, and intracellular release of calcium pools. Neutrophils challenged with the washed RSV exhibited significantly lower activation of surface marker expression (P < 0.001) and oxidative burst (P < 0.001) than those challenged with unwashed virus or with virus free supernatant. There was no increase in intracellular calcium release on exposure to the washed RSV. Purified G glycoprotein did not stimulate neutrophils, whilst the use of a blocking antibody to the F protein did not prevent unwashed RSV from activating cytotoxic responses. These results suggest that neutrophils have no innate signalling system that recognizes RSV but they are activated at sites of RSV infection as a result of the cytokines and inflammatory molecules released by virally infected cells.     

Glutamine depletion potentiates leucocyte-dependent inflammatory events induced by carrageenan or Clostridium difficile toxin A in rats

This research investigated the effect of glutamine (Gln) depletion on leucocyte-dependent inflammatory events. Rats were treated intraperitoneally, 16 hr prior to the peak of every parameter evaluated, with either 0.9% NaCl, methionine-sulphoximine (MSO, an inhibitor of endogenous Gln synthesis, 25 mg/kg) or with MSO + Gln (MSO as above plus Gln 3 g/kg in three doses). MSO-induced Gln depletion increased paw oedema induced both by carrageenan (Cg) and by Clostridium difficile toxin A (TxA) (66.2% and 45.5%, respectively; P < 0.05). In dextran-injected animals, oedema and myeloperoxidase (MPO) activity were not modified by Gln depletion. In Cg-treated paws, Gln depletion increased MPO activity by 44% (P < 0.05), interleukin-1beta (IL-1beta) and tumour necrosis factor-alpha (TNF-alpha) concentrations by 47% and 52%, respectively (P < 0.05), and immunostaining for TNF-alpha in paw tissue. In TxA-injected paws, Gln depletion increased MPO activity (46%; P < 0.05). Gln depletion increased Cg- and TxA-induced neutrophil migration to subcutaneous air pouches by 56% and 77% (P < 0.05), respectively, but did not affect migration induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP). Gln infusions reversed all the effects of MSO. Leucocyte counts did not differ between groups. Gln depletion potentiates acute inflammation, possibly by increasing neutrophil migration through resident cell activation and production of IL-1beta and TNF-alpha. Gln supplementation reverses these effects and may be useful during inflammatory catabolic stress.     

Regulation of human neutrophil chemokine receptor expression and function by activation of Toll-like receptors 2 and 4

Neutrophil chemokine receptor expression can be altered by exposure to Toll-like receptor (TLR) agonists, a process that is thought to have the potential to localize neutrophils to sites of infection. In order to investigate this process in more detail, we examined the regulation of highly pure neutrophil CXCR1 and CXCR2 expression and function by selective agonists of TLR2 (Pam(3)CSK(4)) and TLR4 (lipopolysaccharide, LPS). CXCR1 and CXCR2 were down-regulated by TLR engagement. CXCR2 loss was more rapid and showed a dependence upon soluble helper molecules (LPS binding protein and CD14) that was not evident for CXCR1, suggesting differential coupling of LPS signalling to CXCR1 and CXCR2 loss. However, TLR engagement in highly pure neutrophils did not result in complete loss of chemokine receptors, and LPS-treated neutrophils remained able to mount a respiratory burst to CXCL8 and CXCL1, and were able to migrate towards CXCL8 in assays of under-agarose chemotaxis. Thus, although treatment of purified human neutrophils with TLR2 and TLR4 agonists modifies chemokine receptor expression, remaining receptors remain functionally competent.     

Efficacy of recombinant granulocyte colony-stimulating factor (rhG-CSF) in experimental colitis

Inflammatory bowel disease is associated with mucosal neutrophil recruitment and activatation, mediated in part by arachidonic acid metabolites. G-CSF attenuates the immune response to sepsis and ameliorates glycogen storage disease Ib-related colitis. These actions may be effected through the shedding of neutrophil adhesion molecules, or inhibition of proinflammatory mediator synthesis. Immune complex colitis was used to evaluate the effect of rhG-CSF on colonic mucosal inflammation, neutrophil recruitment and the generation of eicosanoids. Immune complex colitis was induced in White New Zealand rabbits. Animals were pretreated with rhG-CSF either 24 h before induction, or at induction, with dosages of 50 and 200 μg/kg. rhG-CSF caused a time- and dose-dependent neutrophilia in all animals. Pretreatment with rhG-CSF resulted in increased tissue myeloperoxidase levels, despite a histologically similar mucosal polymorphonuclear cell infiltrate between treated and control colitis groups. Leukotriene B₄ (LTB₄) and thromboxane B₂ (TXB₂) dialysis fluid levels were lower in treated animals, in particular in the groups receiving two doses (LTB₄: both P < 0.01; TXB₂: both P < 0.01. Prostaglandin E₂ (PGE₂) levels in dialysis fluid of the rhG-CSF-treated animals showed no difference from controls. In this model of experimental colitis, high-dose therapy with G-CSF resulted in a marked decrease of proinflammatory mediators, but mucosal generation of the protective PGE₂ was preserved. These results suggest that prolonged high-dose therapy with G-CSF may have anti-inflammatory effects in colitis.