Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We tested the hypothesis that voluntary running and moderate food restriction alter the acute phase response (APR), one index of nonspecific immune function. Hamsters were kept sedentary or permitted to run and were fed ad libitum or had food restricted for 20 days and were then injected intraperitoneally with saline or lipopolysaccharide (LPS). Fever and circulating interleukin-6, serum amyloid A (SAA), serum iron, and cortisol were measured by biotelemetry, B-9 cell growth assay, indirect enzyme-linked immunosorbent assay, colorimetric analysis, and radioimmunoassay, respectively. The febrile temperature; hypoferremia; and elevation of circulating interleukin-6, SAA, and cortisol after LPS injection were not altered by exercise. Because baseline temperatures were elevated in the exercised hamsters, the change in temperature in response to LPS was less than it was in the sedentary hamsters. Food restriction significantly decreased SAA and elevated cortisol after LPS injection and depressed the absolute temperature to which the core temperature rose in response to LPS in one trial but not in another. Because food restriction depressed baseline temperatures, it also affected the change in temperature after LPS injection. The hypoferremic response to LPS was inhibited in hamsters that were both food restricted and permitted to run. We conclude that exercise does not enhance the APR to a low dose of LPS, whereas food restriction and the combination of exercise and food restriction depress some portions of the APR in hamsters.
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PMID:Effect of voluntary exercise and food restriction in response to lipopolysaccharide in hamsters. 775 14

This study investigated whether the 21-aminosteroid U74389F, an inhibitor of lipid peroxidation, attenuates pathophysiologic changes in experimental pneumococcal meningitis. Infected rats injected intravenously with vehicle of [corrected] U74389F developed increases in regional cerebral blood flow (rCBF), intracranial pressure (ICP), brain water content, and white blood cells (WBC) in cerebrospinal fluid (CSF) within 8 h after intracisternal challenge. Pretreatment with or administration of U74389F 4 h after infection significantly reduced the increase in ICP but had no effect on rCBF increase. Moreover, U74389F pretreatment significantly reduced brain water content and CSF WBC count. In vitro, U74389F inhibited iron-dependent lipid peroxidation of astrocyte cultures and the production of tumor necrosis factor-alpha, interleukin-6, and nitric oxide by stimulated macrophages. These data suggest that U74389F modulates early pathophysiologic alterations in experimental pneumococcal meningitis.
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PMID:Protective effect of a 21-aminosteroid during experimental pneumococcal meningitis. 779

To define the toxicity profile of recombinant human interleukin-6 (rhIL-6) and to study its effect on hematopoiesis, biochemical parameters and other cytokines, rhIL-6 was administered in a phase I-II study to 20 patients with breast carcinoma or nonsmall cell lung cancer. RhIL-6 doses were 0.5, 1.0, 2.5, 5.0, 10, and 20 micrograms/kg/d, with at least three patients per dose level. RhIL-6 was administered 24 hours by continuous intravenous infusion followed by subcutaneous (SC) administration for 6 days, partly on an outpatient basis. RhIL-6-related side effects were fever, headache, myalgia, and local erythema. Starting at 2.5 micrograms/kg/d, these side effects were compounded by nausea, reversible increase in liver enzymes, and anemia. Flu-like symptoms were controllable up to and including 10 micrograms rhIL-6/kg/d with acetaminophen. RhIL-6 increased platelet counts with a decrease in mean platelet volume and increased leukocytes caused by neutrophil, monocyte, and lymphocyte increase, with an increase in T cells and natural killer cells at 1.0 and 2.5 micrograms rhIL-6/kg/d. The reversible anemia was characterized by a decrease in serum iron, and an increase in ferritin and erythropoietin without reticulocytosis. RhIL-6 reduced total cholesterol levels and a dose-related increase of C-reactive protein and serum amyloid A plasma levels was observed. Serum IL-6 levels were increased, especially at 10 and 20 micrograms/kg/d, whereas no change in IL-1 beta and tumor necrosis factor alpha levels was observed. RhIL-6 can be administered with controllable side effects in this setting, up to and including a SC dose of 10 micrograms/kg/d on an outpatient basis, and has a promising stimulating effect on leukopoiesis and thrombopoiesis.
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PMID:Effects of recombinant human interleukin-6 in cancer patients: a phase I-II study. 806 39

Intestinal blood loss as well as chronic inflammation are regarded as the most important mechanisms in the pathogenesis of anemia in Crohn's disease. In addition, cytokines such as interleukin-6 can suppress erythropoietin production. This study was performed to investigate the importance of iron status, inflammatory activity, and endogenous erythropoietin concentrations for the development of anemia in Crohn's disease. In 49 consecutive patients with Crohn's disease, hemoglobin, inflammatory activity (Crohn's disease activity index, C-reactive protein, alpha 1-acid glycoprotein), iron status (serum iron, transferrin, transferrin saturation, ferritin), and serum erythropoietin levels were studied. Anemic (Hb < 12.0 g/dl; N = 16) vs nonanemic patients (Hb > or = 12 g/dl; N = 33) showed reduced iron compartments (eg, ferritin 28.7 +/- 12.9 micrograms/liter vs 63.2 +/- 15.0 micrograms/liter, transferrin saturation 6.2 +/- 1.4% vs 11.5 +/- 1.3%, P < 0.01) but no differences in inflammatory activity. An inverse correlation between erythropoietin and hemoglobin concentrations was found (r = -0.62; P < 0.001), but the increase in erythropoietin levels was inadequate to the degree of anemia. There was no correlation between erythropoietin and interleukin-6 serum levels. Four of five anemic patients with hemoglobin below 10.5 g/dl and erythropoietin levels within the normal range were treated with parenteral iron (200 mg iron saccharate in 250 ml NaCl, weekly, intravenously). Two of them additionally received recombinant human erythropoietin (150 units/kg, 3x weekly, subcutaneously). After five weeks all patients had a marked increase in hemoglobin. However, the mean increase in erythropoietin-treated patients was 5.0 g/dl compared to 2.0 g/dl in the patients with iron therapy only.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Anemia in Crohn's disease. Importance of inadequate erythropoietin production and iron deficiency. 808 99

There is now considerable evidence that cerebral malaria may be related to the over-production of tumour necrosis factor (TNF). Nevertheless, our knowledge is very poor concerning the biological events which lead up to this TNF over-production. Furthermore, interleukin-6 (IL-6) is produced in large amounts during malaria infection and seems to have inhibitory action on TNF production. Anti-malarial drugs were investigated for their ability to interfere with TNF and IL-6 secretion by human non-immune macrophages stimulated by lipopolysaccharides (LPS) or Plasmodium falciparum culture supernatant. Macrophages were pretreated with chloroquine, quinine, proguanil, mefloquine or halofantrine before stimulation. TNF and IL-6 production were suppressed in a dose-dependent manner when macrophages were treated with chloroquine, but not with other anti-malarial drugs. Considering that chloroquine probably acts via lysosomotropic mechanisms, and that iron metabolism may interfere with the non-specific immune response, we focused our attention on these biochemical events in order to investigate the mechanisms by which chloroquine inhibits cytokine production. Our results demonstrated that chloroquine-induced inhibition of TNF and IL-6 production is not mediated through a lysosomotropic mechanism, and that chloroquine probably acts on TNF secretion by disrupting iron homeostasis. Inhibition of IL-6 production seems not to be mediated through these pathways. These observations suggest that chloroquine may help to prevent cerebral malaria whatever the drug sensitivity of the parasite strain, and may provide new tools for an anti-disease therapy regardless of the emergence of parasite multi-drug resistance.
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PMID:Chloroquine-induced inhibition of the production of TNF, but not of IL-6, is affected by disruption of iron metabolism. 824 53

In chronic inflammation it is reported that serum iron is depleted and hepatic iron is increased because of reticuloendothelial system iron blockade. However, recent studies indicate that hepatic parenchymal cells increase the uptake of transferrin-bound iron after in vivo stimulation with bacterial lipopolysaccharide, suggesting that endotoxemia itself or lipopolysaccharide-induced production of inflammation-related cytokines may also be responsible for this phenomenon. In this study the actions of inflammation-related cytokines on the synthesis of iron-binding proteins (transferrin and ferritin) and transferrin receptor and the uptake of transferrin-bound iron were investigated in a human hepatoblastoma cell line, HepG2, which is the most commonly used cell line for examining the regulation of hepatic protein synthesis by cytokines. The cells were exposed to interleukin-1 beta, interleukin-6 or tumor necrosis factor-alpha separately for 24 hr. In each cytokine treatment group, the level of transferrin, which is secreted into the conditioned medium, was found to be decreased compared with that of untreated cells. On the other hand, the biosynthesis of ferritin was markedly elevated after the same treatment. This increase in ferritin by cytokine treatment was diminished when deferoxamine was used concomitantly to deplete intracellular chelatable iron. After stimulation with interleukin-1 beta, interleukin-6 or tumor necrosis factor-alpha, 59Fe-labeled transferrin uptake into the cells was increased by 36%, 48%, or 18%, respectively, and this uptake was inhibited by the addition of excess unlabeled transferrin. A binding study with 125I-labeled diferric transferrin revealed that the three cytokines increased the number of transferrin receptors on the cell surface by 1.15-fold to 1.35-fold.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of iron metabolism in HepG2 cells: a possible role for cytokines in the hepatic deposition of iron. 840 63

Erythropoiesis is controlled by different regulators. Interleukin 3, granulocyte-macrophage colony-stimulating factor and stem cell factor play regulatory functions in the early steps of erythropoiesis. Erythropoietin (Epo) is the main factor which acts positively on the last steps of the production of erythrocytes in mammals. Epo is specific for the erythroid progenitor cells and has only little effect on other cells. The target cells for Epo are the erythroid progenitors (BFUe and CFUe). Epo acts on these progenitors through surface receptors specific for Epo. Epo induces the proliferation and differentiation of erythroid progenitors leading finally to reticulocytes. During this process, certain conditions are required to permit this differentiation: progenitors must be present in sufficient numbers, the bone marrow environment must be normal, and nutrients such as folic acid, vitamin B12 and particularly iron must be available. Elemental iron is an absolute requirement for adequate haemoglobin formation. Indeed, in a normal adult, without any stimulation, the bone marrow synthesizes 4 x 10(14) molecules of haemoglobin per second, each molecule containing four atoms of iron, which roughly corresponds to 20 mg iron. On the other hand, erythropoiesis is negatively regulated by several cytokines. These are macrophage-derived cytokines, including tumour necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), interleukin-6 (IL-6) and transforming growth factor-beta (TGF-beta). All these factors are elevated in the inflammatory state and are implicated in the pathogenesis of anaemia of chronic disease. TNF-alpha has an inhibitory effect on erythroid progenitors either directly or mediated by interferon-beta (INF-beta). IL-1 inhibits erythropoiesis in vivo in mice and in vitro in humans.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cellular mechanism of resistance to erythropoietin. 852 90

To determine if iron chelation therapy alters immune responses in children with cerebral malaria, we retrospectively measured mean serum levels of neopterin, interleukin-4 (IL-4), and IL-6 in children who received desferrioxamine B or placebo for three days in addition to quinine-based therapy. Mean levels of neopterin, IL-4, and IL-6 were elevated above the expected normal range on admission. Neopterin correlated significantly with the degree of anemia, IL-4 with the duration of fever prior to admission, and IL-6 with parasite density. Serial measurements of cytokines and neopterin were performed over four days in 39 children, 21 randomized to receive desferrioxamine B and 18 to receive placebo. Mean concentrations of neopterin did not change significantly in either group while levels of IL-4 increased significantly in the placebo group (P = 0.04) but remained unchanged in the desferrioxamine B group. Interleukin-6 concentrations decreased markedly in both groups (P < 0.025). Stable IL-4 levels in children given desferrioxamine B may represent an inhibition of the T helper lymphocyte-2 (TH-2) response resulting from a strengthened TH-1 response associated with iron chelation therapy. Any effect of iron chelation on immunity in the setting of severe malaria will have to be confirmed in future prospective investigations.
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PMID:Serum neopterin, interleukin-4, and interleukin-6 concentrations in cerebral malaria patients and the effect of iron chelation therapy. 861 42

Systemic-onset juvenile chronic arthritis (SoJCA) is associated with high levels of circulating interleukin-6 (IL-6) and is frequently complicated by severe microcytic anemia whose pathogenesis is unclear. Therefore, we studied 20 consecutive SoJCA patients with hemoglobin (Hb) levels <12 g/dL, evaluating erythroid progenitor proliferation, endogenous erythropoietin production, body iron status, and iron supply for erythropoiesis. Hb concentrations ranged from 6.5 to 11.9 g/dL. Hb level was directly related to mean corpuscular volume (r = .82, P < .001) and inversely related to circulating transferrin receptor (r = -.81, P < .001) suggesting that the severity of anemia was directly proportional to the degree of iron-deficient erythropoiesis. Serum ferritin ranged from 18 to 1,660 microgram/L and was unrelated to Hb level. Bone marrow iron stores wore markedly reduced in the three children investigated, and they also showed increased serum transferrin receptor and normal-to-high serum ferritin. All 20 patients had elevated IL-6 levels and normal in vitro growth of erythroid progenitors. Endogenous erythropoietin (epo) production was appropriate for the degree of anemia as judged by both the observed to predicted log (serum epo) ratio 10.95 +/- 0.12) and a comparison of the serum epo-Hb regression found in these subjects with that of thalassemia patients. Multiple regression analysis showed that serum transferrin receptor was the parameter most closely related to hemoglobin concentration: variation in circulating transferrin receptor explained 61% of the variation in Hb level (P < .001). In 10 severely anemic patients, amelioration of anemia following intravenous iron administration resulted in normalization of serum transferrin receptor. Defective iron supply to the erythron rather than blunted epo production is the major cause of the microcytic anemia associated with SoJCA. A true body-iron deficiency caused by decreased iron absorption likely complicates long-lasting inflammation in the most anemic children, and this can be recognized by high serum transferrin receptor levels. Although oral iron is of no benefit, intravenous iron saccharate is a safe and effective means for improving iron availability for erythropoiesis and correcting this anemia. Thus, while chronically high endogenous IL-6 levels do not appear to blunt epo production, they are probably responsible for the observed abnormalities in iron metabolism. Anemia of chronic disease encompasses a variety of anemic conditions whose peculiar features may specifically correlate with the type of cytokine(s) predominantly released.
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PMID:Defective iron supply for erythropoiesis and adequate endogenous erythropoietin production in the anemia associated with systemic-onset juvenile chronic arthritis. 863 55

A patient is presented who had Castleman's disease with constitutional symptoms, a palpable supraclavicular/ axillar mass, and a microcytic anemia, among other laboratory abnormalities, including elevated levels of interleukin-6. Treatment consisted of irradiation of the involved area, with subsequent disappearance of all symptoms and normalization of the laboratory abnormalities. Iron kinetic studies demonstrated a hypoproliferative erythropoiesis, which normalized after radiotherapy. Hypoproliferative erythopoiesis could not be ascribed to serum inhibitors, since normal burst-forming units were observed in the absence or presence of autologous serum. The role of interleukin-6 in relation to Castleman's disease is highlighted.
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PMID:A case of localized Castleman's disease with systemic involvement: treatment and pathogenetic aspects. 869 26


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