Leukocyte inhibitory factor activates human neutrophils and macrophages to release leukotriene B4 and thromboxanes

Recent evidence has proved that cytokines can stimulate the production of 5-lipoxygenase products. Leukotriene B4 (LTB4) is a major mediator of leukocyte activation in acute inflammatory reactions, which produce chemotaxis, lysosomal enzyme release, and cell aggregation. Leukocyte inhibitory factor (LIF) also causes biological responses related to inflammation, i.e., LIF directly induces specific granule secretion by polymorphonuclears (PMNs) and potentiates many formyl-methionyl-leucyl-phenylalanine (FMLPs) mediated responses. Since arachidonic acid products are important mediators of inflammation, we have studied the effects of LIF on the arachidonic acid cascade products LTB4 and thromboxane A2 (TxA2). Resuspended at a final concentration of greater than 95% polymorphonuclear PMNs were isolated and tested with some cytokines on the release of LTB4 and TxA2. Peripheral blood mononuclear cells were isolated and seeded in Petri dishes and incubated for 60 min. Adherent macrophages were used for the cytokine stimulation study. Both types of leukocytes were treated with LIF, interleukin 6 (IL 6), and granulocyte-monocyte colony stimulating factor (GM-CSF) at different concentrations, and test agents A23187 and FMLP. Radioimmunoassay for LTB4 and TxB2 was determined by the resulting supernatants. Treatment of PMNs and macrophages with LIF at different concentrations proved to generate significant increases in LTB4 and TxA2 production. This was compared with IL 6 and GM-CSF, which had no effects. In these experiments, TxA2 generations could not be attributed to platelet contamination of PMN suspensions. The quantity of platelet contamination was not sufficient to influence how much TxB2 was produced. The similarities of LIF to other arachidonate stimulating cytokines suggest a similar mode of action in producing hematologic changes typical of tissue injury.(ABSTRACT TRUNCATED AT 250 WORDS)     

Vitamin B6-deficient diet plus 4-deoxypyridoxine (4-DPD) reduces the inflammatory response induced by T. spiralis in diaphragm,masseter and heart muscle tissue of mice

Animals fed diets deficient in vitamin B6 develop microcytic anemia, alterations of growth, and other pathologies. 4-deoxypirydoxine is a potent antagonist of vitamin B6 coenzyme which depresses IL-1, TNF and IL-6 and has anti-inflammatory properties. The aim of this study was to show the anti-infl ammatory effects of 4-DPD on chronic inflammation caused by the nematode parasite T. spiralis, specifically on the recruitment and the activation of inflammatory cells. Two groups of mice, 6 weeks of age, were used: one was maintained on a vitamin B6-deficient synthetic pellet diet for 15 days before injection of the nematode, and administered an intraperitoneal injection (i.p.) of 4-DPD (250 g/mouse) for 15 days (the first, 5 days before infection), and the second group was maintained on a normal diet for the total duration of the experiment. These two groups were then injected with 150 larvae (L1-T. spiralis) per os.Chronic inflammation was caused by infection of treated or untreated mice with T. spiralis parasite. After 14 days post-infection all mice developed a chronic inflammatory response. Mice fed with a B6-deficient diet showed a significant decrease in the number of cysts found in the diaphragm when compared to mice treated with normal diet. In addition, in all mice treated with vitamin B6-deficient diet plus 4-DPD the average body weight was significantly lower, compared to the mice on normal diet in all weeks examined. Moreover, in sections of the diaphragm, masseter and miocardium muscles, the infiltration of inflammatory cells, such as macrophages, lymphocytes, and eosinophils were more intense in untreated mice compared to those fed a vitamin B6-deficient diet.These results show that BALB/c mice infected with T. spiralis and fed a vitamin B6-deficient diet plus the vitamin B6 antagonist, 4-DPD, prolong the time of invasion of the larvae in the muscle cells, influence the recruitment of inflammatory cells and the intensity of the inflammatory reaction compared to infected untreated mice (control)     

Blocking the interleukin-1 receptor inhibits leukotriene B4 and prostaglandin E2 generation in human monocyte cultures.

Interleukin-1 is a potent stimulator of arachidonic acid (AA) metabolism and this activity could be attributed to the activation of the prostaglandin-forming enzyme cyclooxygenase or of the arachidonic-releasing enzyme phospholipase A2 or both. Prostaglandin E2 (PGE2), a cyclooxygenase product, and LTB4 (5-(S),12-(R)-dihydroxy-6,14-cis-8,10-trans-eicosatetraenoic acid), a lipoxygenase product, are potent mediators of inflammation. Recently a new cytokine produced by macrophages and named interleukin-1 receptor antagonist (IL-1ra) (MW 22,000 Da) which specifically binds and blocks IL-1 receptors, has proven to be a potent inflammatory inhibitor. In our studies we found that monocyte suspensions, pretreated with hrIL-1ra at increasing concentrations (0.25-250 ng/ml) for 10 min and then treated with LPS in an overnight incubation inhibits, in a dose-dependent manner, the generation of LTB4 as measured by the highly sensitive radioimmunoassay method. In monocytes pretreated with hrIL-1ra (250 ng/ml) for 10 min and treated with arachidonic acid (10(-5)-10(-9) M) and LPS overnight, the release of LTB4 was partially inhibited when compared to hrIL-1ra-untreated cells. Moreover, hrIL-1ra (250 ng/ml) caused a partial inhibition of monocyte LTB4 production when the cells were activated with AA (10(-7) M) and then treated with IL-1 beta (5 ng/ml) overnight or 24 hr incubation. In addition, human monocytes pretreated for 10 min with increasing doses of hrIL-1ra (0.25-250 ng/ml) and then treated with hrIL-1 alpha (5 ng/ml) or beta (5 ng/ml) for 18 hr, also resulted in the inhibition of PGE2 generation as measured by RIA when compared with hrIL-1ra-untreated cells. When the cells were treated with hrIL-1ra (250 ng/ml) and activated for 18 and 48 hr with increasing doses of hrIL-1 beta a strong inhibitory effect was found on PGE2 production. HrIL-1ra used at 15 ng/ml gave a partial inhibition of LTB4 generation, after LPS (1-100 ng/ml) treatment, while NDGA totally blocked the production of LTB4. Moreover, PGE2 released by macrophages activated with LPS (100 ng/ml) or hrIL-1 beta (5 ng/ml) at 18 hr incubation time was strongly inhibited when hrIL-1ra (250 ng/ml) was used. These data suggest that the inhibition of LTB4 and PGE2 by this new macrophage-derived monokine IL-1ra occurs through the block of the IL-1 receptor, rather than phospholipase A2, and thus IL-1ra may offer a potential therapeutic approach to inflammatory states.     

Induction of monocyte chemotactic protein-1 (MCP-1) and TNF alpha by Trichinella spiralis in serum of mice in vivo

Effects of selenium deficiency, induced by thioacetamide, were investigated in rats. Thioacetamide (0.3 g/L) given in drinking water, as expected, caused a significant loss of selenium from the liver. It was accompanied by liver cirrhosis and a significant increase in the liver weight as well as liver to body weight ratio. A significant loss of selenium from spleen was also accompanied by an increase in its weight. Weights of lungs, testis and kidney, however, were not affected by thioacetamide and there was no change in their selenium content. Plasma levels of selenium were significantly reduced in the thioacetamide treated group. All these changes were confirmed to be due to selenium deficiency caused by thioacetamide, as supplementation with selenium reversed these changes. The mode of action of selenium is unknown but may involve anti-oxidant defense mechanisms.     

Reduced human lymphocyte blastogenesis and enhancement of adenosine triphosphate (ATP) by L-carnitine

The spice principles curcumin (from turmeric) and eugenol (from cloves) are good inhibitors of lipid peroxidation. Lipid peroxidation is known to be initiated by reactive oxygen species. The effect of curcumin and eugenol on the generation of reactive oxygen species in model systems were investigated. Both curcumin and eugenol inhibited superoxide anion generation in xanthine-xanthine oxidase system to an extent of 40% and 50% at concentrations of 75 M and 250 M respectively. Curcumin and eugenol also inhibited the generation of hydroxyl radicals (^.OH) to an extent of 76% and 70% as measured by deoxyribose degradation. The^.OH-radical formation measured by the hydroxylation of salicylate to 2,3-dihydroxy benzoate was inhibited to an extent of 66% and 46%, respectively, by curcumin and eugenol at 50 M and 250 M. These spice principles also prevented the oxidation of Fe²⁺ in Fentons reaction which generates^.OH radicals.     

Production of MCP-1 and RANTES in bladder cancer patients after bacillus Calmette-Guerin immunotherapy

Bacillus Calmette-Guerin (BCG) therapy induces a local immunological response mediated by cellular immune and inflammatory reactions that enhance its anti-tumor efficacy in bladder cancer. Monocyte chemotactic protein-1 (MCP-1) and the "regulated on activation normal T expressed and secreted" chemokine (RANTES) are potent chemotactic molecules that attract monocytes and memory T cells. MCP-1 and RANTES levels in patients with superficial bladder cancer treated with intravesical instillations of BCG are significantly higher than in untreated cancer patients and controls. In the present study, the subjects were divided into three groups: (1) control subjects; (2) bladder cancer patients who did not receive BCG treatment; (3) bladder cancer patients who received intravesical administration of BCG. No differences in the basal production and expression of MCP-1 and RANTES mRNA were observed between BCG-treated and untreated patients. BCG treatment influenced the monocyte response to phytohemagglutinin (PHA) and BCG stimulation. After 24-h incubation, monocytes from BCG-treated bladder cancer patients released more MCP-1 and RANTES than those from untreated bladder cancer patients and controls. The anti-tumor effects of BCG observed in superficial bladder cancer therapy may depend on stimulation of the investigated chemokines, which attract monocytes/macrophages and memory T cells.     

Effect of interleukin-1 receptor antagonist (IL-1RA) on histamine and serotonin release by rat basophilic leukemia cells (RBL-2H3) and peritoneal mast cells

Recently, it has been appreciated that cultured mast cells are significant sources of cytokines. However, the role of interkeukin-1 (IL-1) on mast cells and/or basophil degranulation is still unclear. In this report we provide evidence that rat basophilic leukemia cells (RBLC) cultured with a natural inhibitor of IL-1, interleukin-1 receptor antagonist (IL-1RA) (500 ng/ml) for 48 h, strongly inhibited the spontaneous release of serotonin (5HT) and histamine (from 22.50 to 43.49%), compared to untreated cells (control). When IL-1RA-treated and untreated RBLC were stimulated with a secretagogue (anti-IgE), no difference was found in the percent of 5HT and histamine release. Moreover, in another set of experiments using rat peritoneal mast cells (RPMC) treated and untreated with IL-1RA, we found that IL-1RA did not affect the release of 5HT or histamine, even when the secretagogue anti-IgE or compound 48/80 (C48/80) were used. The present studies describe an additional biological activity of IL-1RA, inhibiting histamine and 5HT release from RBLC cultures.Abbreviations IL-1 interleukin-1 - RA receptor antagonist - 5HT serotonin - RBLC rat basophilic leukemia cells - RPMC rat peritoneal mast cells - IgE immunoglobulin E - Fc immunoglobulin E receptor - CPM counts per minute - BSA bovine serum albumin - C48/80 compound 48/80 - TNF tumor necrosis factor