Eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid differentially modulate rat neutrophil function in vitro.

Fish oils are used as therapeutic agents in chronic inflammatory diseases. The omega-3 fatty acids (FA) found in these oils are mainly eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. The anti-inflammatory properties of fish oils are attributed to both omega-3 fatty acids. However, it is unknown whether such effects are due to either EPA or DHA. In this study, the effects of EPA and DHA on rat neutrophil function in vitro were compared. Both EPA and DHA increased the production of H2O2 when cells were stimulated or not with lipopolysaccharides (LPS). However, EPA was more potent than DHA in triggering an increase in superoxide release by cells in the basal condition or when stimulated with phorbol myristate acetate (PMA) or zymosan. Only DHA increased the phagocytic capacity and fungicidal activity of neutrophils. Both FA increased the release of tumor necrosis factor-α (TNF-α) in nonstimulated cells, but only EPA increased the production of cytokine-inducing neutrophil chemoattractant-2 (CINC-2) in the absence or presence of LPS, whereas production of interleukin-1 beta (IL-1ß) was only increased by DHA in the presence of LPS. In addition, there was no alteration in the production of nitric oxide. In conclusion, we show herein that EPA and DHA can differently modulate aspects of the neutrophil response, which may be relevant for the development of therapies rich in one or other FA depending on the effect required.

Role of enteral nutrition supplemented with ebselen and EHEC in pancreatitis-associated multiple organ dysfunction in rats.

OBJECTIVES: To investigate potential effects of ebselen and ethylhydroxyethyl cellulose (EHEC) on the acute phase responses and the severity of multiple organ dysfunction associated with acute pancreatitis. METHODS: Acute pancreatitis was induced by intraductal infusion of 5% sodium taurodeoxycholate. The increase of total protein content in the BALF was used as an indication for acute lung injury, plasma amylase for pancreatic damage, plasma bilirubin for acute liver dysfunction, and plasma creatinine for acute kidney dysfunction. Levels of interleukin (IL)-6, macrophage inflammatory protein (MIP)-2 in the BALF were determined by ELISA. RESULTS: There was a dose-related tendency for ebselen or EHEC alone to prevent organ dysfunction and reduce elevated plasma levels of IL-6 and ICAM-1 expression on circulating leukocytes 12 h after AP induction. The combination of ebselen and EHEC significantly prevented pancreatitis-induced multiple organ injury, IL-6 production and ICAM-1 expression in rats and exhibited better effects than either monocompound alone. CONCLUSION: The combination of ebselen and EHEC may be a new potential for treatment of acute severe pancreatitis.

Modulation of cytokine secretion by pentacyclic triterpenes from olive pomace oil in human mononuclear cells.

Olive pomace oil, also known as "orujo" olive oil, is a blend of refined-pomace oil and virgin olive oil, fit for human consumption. Maslinic acid, oleanolic acid, erythrodiol, and uvaol are pentacyclic triterpenes, found in the non-glyceride fraction of orujo oil, which have previously been reported to have anti-inflammatory properties. In the present work, we investigated the effect of these minor components on pro-inflammatory cytokine production by human peripheral blood mononuclear cells in six different samples. Uvaol, erythrodiol, and oleanolic acid significantly decreased IL-1beta and IL-6 production in a dose-dependent manner. All three compounds significantly reduced TNF-alpha production at 100microM; however, at 10microM, uvaol and oleanolic acid enhanced the generation of TNF-alpha. In contrast, maslinic acid did not significantly alter the concentration of those cytokines, with the exception of a slight inhibitory effect at 100microM. All four triterpenes inhibited production of I-309, at 50microM and 100microM. However, uvaol enhanced I-309 production at 10microM. The triterpenic dialcohols had a similar effect on MIG production. In conclusion, this study demonstrates that pentacyclic triterpenes in orujo oil exhibit pro- and anti-inflammatory properties depending on chemical structure and dose, and may be useful in modulating the immune response.

Detection of interferon-gamma-inducible chemokines in human milk.

AIM: To assess the immunological role of human milk by analysing the concentrations of interferon-gamma-inducible protein of 10 kda (IP-10) and monokine induced by interferon-gamma (MIG) in human milk from mothers of preterm and term infants. METHODS: IP-10 and MIG levels of colostrum, early milk, mature milk and sera were measured by enzyme-linked immunosorbent assay (ELISA). IP-10 and MIG mRNA expression levels in cellular components of human milk were determined by RT-PCR. IP-10 and MIG protein expression in mammary gland tissues was analysed by immunohistochemistry. RESULTS: Significant amounts of IP-10 and MIG were detected in human milk. The concentrations of IP-10 and MIG in colostrum and early milk were significantly higher than those of sera from healthy controls or lactating mothers. These chemokine concentrations in colostrum and early milk were significantly higher than those of mature milk. Premature delivery or pregnancy complications of mothers had no significant correlation with these chemokine concentrations in breast milk. There were significant correlations between MIG and interferon-gamma (IFN-gamma) or IP-10 levels (p < 0.001) in human milk. Expression of IP-10 and MIG genes and proteins in the milk cells as well as in mammary gland epithelial tissues was detected by RT-PCR and immunohistochemistry. CONCLUSION: IP-10 and MIG in human milk, probably derived from milk cells and mammary gland epithelial cells, may contribute to the migration and activation of intestinal T lymphocytes to enhance mucosal immunity during the early neonatal period.

Chemokine receptor CXCR2 regulates the functional properties of AMPA-type glutamate receptor GluR1 in HEK cells.

Experiments were conducted in both HEK cells and cerebellar neurons to investigate whether CXC chemokine receptor 2 (CXCR2) is functionally coupled to GluR1. The co-expression of CXCR2 with GluR1 in HEK cells increased (i) the GluR1 "apparent" affinity for the transmitter; (ii) the GluR1 channel open probability; and (iii) GluR1 binding site cooperativity upon CXCR2 stimulation with CXC chemokine ligand 2 (CXCL2). The affinity of C-terminal-deleted GluR1 for glutamate (Glu) remained stable instead. Furthermore, CXCL2 increased the binding site cooperativity of AMPA receptors in rat cerebellar granule cells; and the amplitude of spontaneous excitatory postsynaptic current (sEPSCs) in Purkinje neurons (PNs). Our findings indicate that the coupling of CXCR2 with GluR1 may modulate glutamatergic synaptic transmission.

Characterization and visualization of [125I] stromal cell-derived factor-1alpha binding to CXCR4 receptors in rat brain and human neuroblastoma cells.

Stromal cell-Derived Factor-1 (SDF-1alpha), binds to the seven-transmembrane G protein-coupled CXCR4 receptor and modulates cell migration, differentiation, and proliferation. CXCR4 has been reported to be expressed in various tissues including brain. Moreover, CXCR4 has recently been shown to be one of the coreceptors for HIV-1 infection which could be implicated in HIV encephalitis. In the present study, the binding properties and autoradiographic distribution of [125I]SDF-1alpha binding to CXCR4 were characterized in the adult rat brain. SDF-1alpha binding and CXCR4 coupling system were also studied in human neuroblastoma cell line SK-N-SH. The binding of [125I]SDF-1alpha on rat brain sections was specific, time-dependent and reversible. The highest densities of CXCR4 were detected in the choroid plexus of the lateral and the dorsal third ventricle. Lower densities of [125I]SDF-1alpha binding sites were observed in various brain regions including cerebral cortex, anterior olfactory nuclei, hippocampal formation, thalamic nuclei, blood vessels and pituitary gland. In the choroid plexus, the IC(50) and K(d) of [125I]SDF-1alpha binding were respectively 0.6 nM and 0. 36 nM. Similar IC(50) values were obtained in other brain structures. A CXCR4 antagonist, bicyclam, competed with SDF-1alpha binding (30% inhibition at 10(-6) M). In SK-N-SH cells, [125I]SDF-1alpha bound to CXCR4 with a K(d) of 5.0 nM and a maximal binding capacity of 460 fmol/mg of protein. SDF-1alpha induced a rapid and transient intracellular calcium increase in SK-N-SH cells. These findings suggest that CXCR4 is highly expressed in some brain structures and have a regulatory role in the nervous system. The significance of this expression in the brain parenchyma and more specifically in the choroid plexus remains to be clarified in the normal as well as in the infected brain.

Involvement of growth-related protein in lipopolysaccharide-induced rabbit arthritis: cooperation between growth-related protein and IL-8, and interrelated regulation among TNFalpha, IL-1, IL-1 receptor antagonist, IL-8, and growth-related protein.

We investigated the functional role of a CXC chemokine, growth-related protein (GRO), in the recruitment of neutrophils in lipopolysaccharide (LPS)-induced rabbit arthritis. The amounts of GRO in the synovial fluids (SF) reached the first peak (major) at 2 hours and the second peak (minor) at 9 hours after injection of LPS into the knee joints. Administration of anti-GRO mouse monoclonal antibody inhibited 54% of the peak leukocyte accumulation at 9 hours (neutrophils greater than 95%), which was similar to the inhibition by anti-IL-8 IgG (48%). Co-administration of these inhibitors increased the inhibition up to 70% at 9 hours and also inhibited 65% of the initial phase of leukocyte infiltration at 2 hours (neutrophils greater than 99%), which was not affected by a single administration of each inhibitor. The amounts of GRO in SF at 2 hours were not altered by either anti-TNFalpha mAb or anti-IL-8 IgG, but reduced by rabbit recombinant IL-1 receptor antagonist (rrlL-1Ra) by 39%. The inhibition by rrlL-1 Ra was augmented further to 59% with coadministered anti-TNFalpha mAb. In contrast, the amounts of GRO at 9 hours were reduced by rrlL-1Ra by 67%. There was no additional reduction in the amounts of GRO at 9 hours by either combination of rrlL-1Ra with anti-TNFalpha mAb or anti-IL-8 IgG. Administration of anti-GRO mAb did not alter TNFalpha or IL-8 contents in SF at their peak (2 hours), but reduced the amounts of IL-1beta at 6 hours and IL-1Ra at 9 hours by 42% and 49%, respectively. These results provide evidence for the following: (a) GRO as well as IL-8 are important mediators involved in the recruitment of neutrophils both in the early and the late phase of LPS-induced arthritis, (b) IL-1 produced in the early phase stimulates GRO production, (c) GRO plays a role in the later induction of IL-1beta and IL-1Ra, and (d) induction of GRO is not regulated by IL-8.

The CXC-chemokine, H174: expression in the central nervous system.

H174 is a new member of the CXC-chemokine family. A cDNA probe containing the entire H174 coding region recognized a predominant inducible transcript of approximately 1.5 kb expressed in interferon (IFN) activated astrocytoma and monocytic cell lines. H174 message can be induced following IFN-alpha, IFN-beta, or IFN-gamma stimulation. H174 message was also detected in IFN treated cultures of primary human astrocytes, but was absent in unstimulated astrocytes. H174, like IP10 and Mig, lacks the ELR sequence associated with the neutrophil specificity characteristic of most CXC-chemokines. Preliminary experiments suggest H174, IP10 and Mig are independently regulated. Recombinant H174 is a weak chemoattractant for monocyte-like cells. H174 can also stimulate calcium flux responses. The data support the classification of H174 as a member of a subfamily of interferon-gamma inducible non-ELR CXC-chemokines. Brain tissues were obtained at autopsy from one patient with AIDS dementia, one patient with multiple sclerosis, and two normal control patients. H174 and Mig were detected by RT-PCR in brain tissue cDNA derived from the patients with pathological conditions associated with activated astrocytes but not in cDNA from control specimens.