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Changes and correlations in cytokine and eicosanoid production by blood monocytes, non-purified and purified peritoneal cells during a carrageenin-induced peritonitis were investigated for a period of ten days. The cells were isolated and stimulated in vitro. Cytokine and eicosanoid production of the non-purified fraction increased steadily during peritonitis. During the whole episode of peritonitis the production capacity of granulocytes was very low and hardly any effect on the production capacity of macrophages (Mvarphi) was observed. Cytokine and eicosanoid production of the non-purified fraction was mainly due to the presence of Mvarphi. The production capacity of the peripheral blood monocytes was not similar to that of the peritoneal Mvarphi.

THE acyl carrier coenzyme A (CoA) is involved in fatty acid metabolism. The carnitine/CoA ratio is of particular importance in regulating the transport of long-chain fatty acids into mitochondria for oxidation. Also CoA has a role in the formation and breakdown of products from both the cyclooxygenase and lipoxygenase pathways of the precursor arachidonic acid. In the present study the effect of 4 days feeding of 300 mg/kg/day of L-carnitine, acetyl Lcarnitine and propionyl L-carnitine on the basal and calcium ionophore (A23187) stimulated release of arachidonic acid metabolites from rat carrageenin elicited peritoneal cells was investigated. There were two series of experiments carried out. In the first, the harvested peritoneal cell population consisted of less than 90% macrophages and additional polymorphonuclear (PMN) leucocytes. The basal release of prostaglandin E(2) (PGE(2)), 6-ketoprostaglandin F(1alpha) (6-keto-PGF(1alpha)) and leukotriene B(4) (LTB(4)) was stimulated by all treatments. The A23187 stimulated release of 6-keto-PGF(1alpha) and LTB(4) was increased by all three compounds. The 6-keto-PGF(1alpha):TxB(2) and 6-keto-PGF(1alpha):LTB(4) ratios were increased by carnitine treatment. These results suggested that carnitine could modify the macrophage component of an inflammatory site in vivo. In the second series of experiments the harvested cell population was highly purified (95% macrophages) and none of the compounds fed to the rats caused a change of either eicosanoid or TNFalpha formation. Moreover the 6-keto-PGF(1alpha):TxB(2) and 6-keto-PGF(1alpha):LTB(4) ratios were not enhanced by any of the compounds tested. It is conceivable that in the first series the increased ratios 6-keto-PGF(1alpha):TxB(2) and 6-keto-PGF(1alpha):LTB(4) reflected the effect of carnitine or its congeners on PMN leucocytes rather than on macrophages.

Human peritoneal macrophages (hp-M phi) are a source of inflammatory mediators. After stimulation in vitro for 24 h with LPS there was a significant increase in cytokine production (IL-1, IL-6 and TNF alpha), but not in the production of eicosanoids from endogenous arachidonate. Leukotrienes are the predominant eicosanoids formed after stimulation with calcium ionophore for 15 min, while prostaglandin formation is insignificant. The fluorescence intensity of TPA-stimulated and DHR123 loaded hp-M phi (a measure of the respiratory burst) increases significantly in a short period of time. Hp-M phi will be useful as a model for testing the effects of anti-inflammatory drugs on eicosanoid and cytokine production and respiratory burst activity in vitro.

To assess the diagnostic and prognostic value of interleukin-6, interleukin 1 beta, and tumor necrosis factor-alpha assays in plasma and ascites, we measured these cytokines in eight patients with malignancy-related ascites and 32 patients with decompensated cirrhosis. Five patients had an episode of bacterial peritonitis, during which one or more ascitic fluid samples were analyzed. Interleukin-6 and tumor necrosis factor-alpha were not significantly different between the cirrhotic and the malignant groups: ascitic interleukin-6 13,816 +/- 15,314 vs 28,138 +/- 23,403 pg/ml, plasma interleukin-6 542 +/- 719 vs 559 +/- 604 pg/ml; ascitic tumor necrosis factor-alpha 19 +/- 50 vs 12 +/- 31 pg/ml, plasma tumor necrosis factor-alpha 3.4 +/- 8.2 vs 6.1 +/- 13.8 pg/ml. During an episode of bacterial peritonitis there was a significant increase only in ascitic interleukin-6 (133,268 +/- 99,743 pg/ml), which declined after antibiotic treatment. None of the parameters was associated with 6-month survival (11 of the 40 patients died within 6 months). There was a correlation (r = 0.675; p = 0.002) between plasma interleukin-6 levels and the Child-Pugh score in patients with cirrhosis, but not with the etiology of the liver disorder. Plasma interleukin-6 levels correlated with IgA levels (r = 0.649; p = 0.004) but not with C reactive protein, sedimentation rate, fibrinogen, IgM or IgG. These results do suggest that interleukin-6 is produced within the peritoneal cavity in hepatic and malignant ascites. There is a sharp increase in the local production of interleukin-6 during an episode of bacterial peritonitis.(ABSTRACT TRUNCATED AT 250 WORDS)

The levels of the eicosanoids leukotriene B4, prostaglandin E2, prostacycline and thromboxane B2, the cytokines interleukin-1 beta, interleukin-6 and tumour necrosis factor-alpha and soluble intercellular adhesion molecule 1 were measured in ascites and plasma samples of patients with liver cirrhosis (53), peritoneal cancer (26) and spontaneous bacterial peritonitis (10) to assess their value as a possible diagnostic and prognostic parameter in the course of the disease. Soluble intercellular adhesion molecule 1, of the eicosanoids prostaglandin E2 and leukotriene B4, and the protein concentration in ascites were all significantly elevated in ascites of patients with peritoneal cancer in comparison to ascites of patients with liver cirrhosis. In ascites of patients with spontaneous bacterial infection interleukin-6 concentration was significantly elevated and the protein concentration was significantly lower in comparison to the other two groups. None of these parameters, however, seems to be of practical use as a diagnostic parameter, as there is an overlap between all the levels of these mediators in ascites of liver cirrhosis, peritoneal cancer and spontaneous bacterial peritonitis group. Soluble intercellular adhesion molecule 1 levels were much higher in plasma than in ascites, in contrast to interleukin-6 levels which were much higher in ascites than in plasma. Soluble intercellular adhesion molecule 1 in ascites correlated with soluble intercellular adhesion molecule 1 in plasma (r = 0.6926, P = 0.0001). Soluble intercellular adhesion molecule 1, interleukin-6 and the number of polymorphonuclear cells in peritoneal fluid correlated during episodes of infection in patients with a peritonitis. For this reason soluble intercellular adhesion molecule 1 and interleukin-6 could be of prognostic value for patients with peritonitis.

To examine the interactions between the main pro-inflammatory cytokines and eicosanoids produced by human inflammatory cells, human peritoneal macrophages (hp-M phi) were isolated from ascitic fluid of patients with portal hypertension. Interactions between interleukin-1 beta (IL-1 beta), IL-6, tumor necrosis factor alpha (TNF-alpha), leukotriene B4 (LTB4) and prostaglandin E2 (PGE2) were studied by addition or inhibition of several cytokines and eicosanoids: human recombinant IL-1 beta (hrIL-1 beta) addition, LTB4 addition and 5-lipoxygenase inhibition (6-hydroxy-2-(4-sulfamoylbenzylamino)-4,5,7-trimethylbenzothiaz ole hydrochloride (E6080)), PGE2 addition and cyclooxygenase inhibition (indomethacin). In hp-M phi hrIL-1 beta stimulated the LTB4 production, while the PGE2 production was inhibited. HrIL-1 beta had no significant effect on IL-6 production in hp-M phi. LTB4 did not regulate IL-1 beta and IL-6 production. Increasing PGE2 down regulated the TNF-alpha production, but did not effect the IL-1 beta and IL-6 production.

Ascites is a readily available source of human macrophages (M phi), which can be used to study M phi functions in vitro. We characterized the mediators of inflammation produced by human peritoneal M phi (hp-M phi) obtained from patients with portal hypertension and ascites. The production of the cytokines interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) was found to be lipopolysaccharide (LPS) concentration dependent (0-10 micrograms/ml) with a maximal production at 10 micrograms/ml and also dependent on the time of exposure to the stimulus (0-36 h). IL-1 beta, IL-6 and TNF-alpha production after LPS administration reached a plateau at 24 h. In vitro stimulation for 24 h with LPS does not influence the eicosanoid production from endogenous arachidonate. 13 min of exposure of the cells to the calcium ionophore A23187 gives a significant increase in eicosanoid production from both exogenous and endogenous arachidonate. The main eicosanoids produced are the 5-lipoxgenase products LTB4 and 5-hydroxyeicosatetraenoic acid (HETE). The increase in production of the other eicosanoids is not significant. The eicosanoid production depends on the stimulus concentration. The optimal A23187 concentration is 1 microM. Oxygen radical production was measured in the M phi by a flowcytometric method. The fluorescence intensity of phorbol 12-myristate 13-acetate stimulated and dihydro-rhodamine 123 loaded hp-M phi increases significantly after 15 min. We conclude that LPS stimulation of hp-M phi from liver disease results in similar production of IL-1 beta, IL-6 and TNF-alpha, but that the profile of the eicosanoid production of these M phi stimulated with LPS and A23187 differs from M phi of other origin and species.

This study was performed to determine the selectivity of the 5-lipoxygenase inhibitor 6-Hydroxy-2- (4-sulfamoylbenzylamino)-4,5,7-trimethylbenzothiazole hydrochloride (E6080) on the in vitro eicosanoid metabolism in human peritoneal cells of patients with ascites. The IC50 for E6080 on the formation of the 5-lipoxygenase products LTB4 and 5-HETE was respectively 3.7 μM and 1.7 μM. The production of the other lipoxygenase (8-, 12-, 15-HETE) and cyclooxygenase products (HHT, 6kPGF1 α, TXB2, PGF2 α, PGE2 and PGD2) were not significantly inhibited in the dose range we have studied (0.3 μM–30 μM). E6080 is specific and equipotent to most of the known potent 5-lipoxygenase inhibitors.

Density-defined macrophages isolated from fluids of patients with liver cirrhosis mainly generated the 5-lipoxygenase products leukotriene B4 (LTB4, 16%) and 5-hydroxy-eicosatetraenoic acid (5-HETE, 24%) and the cyclooxygenase products 12-hydroxyheptadecatrienoic acid (HHT, 22%) and thromboxane B2 (TXB2, 18%). The synthesis of eicosanoids was linear with the maturity of the macrophage subpopulations, suggesting that eicosanoid production is increased in in-vivo activated macrophages.