Estrogen inhibits lipopolysaccharide-induced tumor necrosis factor-alpha release from murine macrophages.

During their reproductive years, female have a lower risk for atherosclerosis as compared with age-matched males, although the mechanisms behind this are not clearly understood. Cytokines, including TNF-alpha play an important role in the pathogenesis of atherosclerosis. We therefore evaluated whether or not there was any difference between 17 beta-estradiol and testosterone in modulating TNF-alpha release from murine bone marrow-derived macrophages (BMM) in vitro. Cells were incubated with or without physiological concentrations (10(-10)-10(-8) M) of 17 beta-estradiol or testosterone for 48 h, followed by an additional 6 h in the absence or presence of lipopolysaccharide (LPS; 10 micrograms/ml). The amount of TNF-alpha released into the culture medium was determined with radioimmunoassay. We found that 17 beta-estradiol or testosterone alone did not affect TNF-alpha release from BMM as compared to untreated controls. Preincubation with 17 beta-estradiol significantly inhibited LPS-induced TNF-alpha release by 18.15% (p < 0.05). 25.28% (p < 0.05) and 40.83% (p < 0.01) for 10(-10), 10(-9) and 10(-8) M of 17 beta-estradiol, respectively, as compared to LPS alone. In contrast, testosterone tested for 3 concentrations did not significantly effect TNF-alpha release induced by LPS. The results indicate that 17 beta-estradiol, but not testosterone, inhibits TNF-alpha release from LPS-stimulated macrophages, which may be one of the mechanisms by which estrogen protects against atherosclerosis.     

Rehmannia glutinosa inhibits tumour necrosis factor-alpha and interleukin-1 secretion from mouse astrocytes.

We investigated whether an aqueous extract of Rehmannia glutinosa steamed root (RGAE) inhibits secretion of tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) from primary cultures of mouse astrocytes. RGAE dose-dependently inhibited the TNF-alpha secretion by astrocytes stimulated with substance P (SP) and lipopolysaccharide (LPS). IL-1 has been shown to elevate TNF-alpha secretion from LPS-stimulated astrocytes while having no effect on astrocytes in the absence of LPS. We therefore investigated whether IL-1 mediated inhibition of TNF-alpha secretion from astrocytes by RGAE. Treatment of RGAE to astrocytes stimulated with both LPS+SP decreased IL-1 secretion. Moreover, incubation of astrocytes with IL-1 antibody abolished the synergistic cooperative effect of LPS+SP. These results suggest that RGAE may inhibits TNF-alpha secretion by inhibiting IL-1 secretion and that RGAE has an anti-inflammatory activity in the central nervous system curing some pathological disease states. 1999 Academic Press@p$hr Copyright 1999 Academic Press.     

Progesterone inhibits mast cell secretion

Mast cells are involved in allergic reactions, where they secrete numerous vasoactive, inflammatory and nociceptive mediators in response to immunoglobulin E (IgE) and antigen. However, they have also been implicated in inflammatory conditions, such as painful bladder syndrome/interstitial cystitis (PBS/IC), irritable bowel syndrome (IBS) and migraines, all of which occur more often in women and are exacerbated during ovulation, but are suppressed during pregnancy. Mast cells express high affinity estrogen receptors and estradiol augments their secretion, while tamoxifen inhibits it. Here we report that progesterone (100 nM), but not the structurally related cholesterol, inhibits histamine secretion from purified rat peritoneal mast cells stimulated immunologically or by substance P (SP), an effect also documented by electron microscopy. These results suggest that mast cell secretion may be regulated by progesterone and may explain the reduced symptoms of certain inflammatory conditions during pregnancy.     

悬钩子属植物化学成分和药理作用研究新进展

悬钩子属为蔷薇科植物,分布广泛,具有广泛的药用价值。通过查阅大量文献资料,发现悬钩子属植物含有萜类、黄酮类、甾类等化学成分,在抗菌、保肝、抗氧化、抗肿瘤、消炎、镇咳等方面发挥着重要作用。本文综述了近些年来关于悬钩子属的化学成分、药理作用等方面的研究进展,为其进一步开发利用提供参考。     

Rutin inhibits nitric oxide and tumor necrosis factor-alpha production in lipopolysaccharide and concanavalin-a stimulated macrophages

The effect of rutin, a flavonoid present in onions, apples, tea and red wine, on the production of nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) was analyzed using in vitro as well as in vivo systems. The level of nitrite in lipopolysaccharide (LPS) stimulated BALB/c mice (88.21 microM) was significantly reduced in rutin treated animals (16.92 microM). The nitrite level in concanavalin-A (Con-A) treated control animals (77.15 microM) was also significantly reduced to 11.03 microM when the animals were pretreated with rutin. The drastically elevated levels of TNF-alpha in LPS stimulated animals (686.8 pg/ml) was lowered by pretreatment with rutin (182.4 pg/ml). Rutin also inhibited Con-A induced TNF-alpha production. Rutin inhibited nitrite production by activated macrophages in vitro (74.75 microM) to the normal level (16.13 microM) at a concentration of 5 microg/ml. In vitro L929 bioassay also showed inhibition of TNF-alpha production by rutin treatment.     

Nifedipine inhibits apoptotic cell death of cultured endothelial cells induced by tumor necrosis factor-alpha

Impaired endothelial cell (EC) growth and function have been suggested to be an initial event that leads to the development of atherosclerosis. We have very recently found that nifedipine, one of the most popularly used dihydropyridine-based calcium antagonists, prevented EC monocyte chemoattractant protein-1 production elicited by tumor necrosis factor-alpha (TNF-alpha through its antioxidative properties. However, the effects of nifedipine on EC growth and apoptosis are not fully understood. In this study, we investigated whether nifedipine could inhibit tumor necrosis factor (TNF)-alpha-induced growth retardation and apoptotic cell death in human umbilical vein ECs (HUVECs). TNF-alpha inhibited EC proliferation, which was significantly blocked by nifedipine or antioxidant N-acetylcysteine (NAC). Nifedipine or NAC was also found to significantly inhibit apoptotic cell death of TNF-alpha-exposed HUVECs. Our present study suggests that nifedipine may play a protective role against the development and progression of atherosclerosis by promoting EC repair through its antioxidative properties.     

Serum tumor necrosis factor-alpha in pre eclampsia

Cytokines are major contributors in pathogenesis of pre eclampsia. Serum TNF-alpha was determined in 10 normal and 30 pre-eclamptic pregnant females with special reference to maternal age, parity and levels of mean arterial blood pressure. TNF-alpha was determined using sandwich ELISA technique. Serum TNF-alpha level in normal pregnant females was 9.3 +/- 0.56 pg/ml, while in pre-eclamptic pregnant females it was 67.66 +/- 61.83 pg/ml. This increase TNF-alpha was highly significant (P < 0.001). There was no significant changes in serum TNF-alpha with respect to maternal age, parity and mean arterial pressure in both normal and pre-eclamptic pregnancies.     

Infections associated with tumor necrosis factor-alpha antagonists

Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine involved in a wide range of important physiologic processes. This cytokine has a pathologic role in some diseases, and TNF-alpha antagonists are effective in treating inflammatory conditions. Given the putative role of TNF-alpha in host defense against tuberculosis and other infections, the risk of infection with TNF-alpha antagonists is a concern. Therefore, we searched the literature for reports of tuberculosis and other infections associated with TNF-alpha-antagonist therapy. Although tuberculosis was rarely reported in randomized clinical comparisons of these antagonists, case reports and submissions to the MedWatch program of the United States Food and Drug Administration have been numerous. Most instances were associated with infliximab, but etanercept and adalimumab may also be associated with an increased risk of tuberculosis. Histoplasmosis, listeriosis, aspergillosis, coccidioidomycosis, and candidiasis have been associated with TNF-alpha antagonists, but the causative relationship is not clear. Potential recipients of these drugs should be rigorously screened with skin testing, detailed questioning about recent travel and potential tuberculosis exposure, assessment for symptoms such as cough and weight loss, and chest radiography to minimize their risk of acquiring or reactivating tuberculosis. As with other immunosuppressant drugs, TNF-alpha antagonists should not be given to patients with active infection.     

Savinin, a lignan from Pterocarpus santalinus inhibits tumor necrosis factor-alpha production and T cell proliferation

Two lignans were isolated from the heartwood of Pterocarpus santalinus by activity-guided fractionation and investigated for their biological properties and molecular mechanism of action. On the basis of their spectroscopic data, these compounds were identified as savinin (1) and calocedrin (2), dibenzyl butyrolactone-type lignan compounds having an alpha-arylidene gamma-lactone structure. These lignans significantly inhibited tumor necrosis factor (TNF)-a production in lipopolysaccharide (LPS)-stimulated RAW264.7 cells, and T cell proliferation elicited by concanavalin (Con A), without displaying cytotoxicity. The molecular inhibitory mechanism of compound 1 was confirmed to be mediated by the non-polar butyrolactone ring, according to a structure-relationship study with structurally related and unrelated compounds, such as arctigenin (a dibenzyl butyrolactone type lignan), eudesmin (a furofuran type lignan), isolariciresinol (a dibenzylbutane type lignan), and cynaropicrin (a sesquiterpene lactone). The results suggest that savinin may act as an active principle in the reported biological activities of P. santalinus, such as antiinflammatory effect, by mediation of the butyrolactone ring as a valuable pharmacophore.     

Ginsenoside Rg1 inhibits proliferation of vascular smooth muscle cells stimulated by tumor necrosis factor-α

AIM: To investigate the proliferation of vascular smooth muscle cells (VSMC) affected by ginsenoside Rg1 and further explore the molecular mechanism of ginsenoside Rg1 using proteomics. METHODS: The proliferation of VSMC was measured by MTS assay kit and flow cytometry. Proteomic alterations were analyzed using two-dimensional electrophoresis and peptide mass fingerprinting. Differential proteins found in proteomics were confirmed by RT-PCR. RESULTS: The proliferation of VSMC was enhanced significantly after tumor necrosis factor-alpha (TNF-alpha) treatment, and ginsenoside Rg1 treatment inhibited proliferation in a dose-dependent manner. Proteomic analysis showed 24 protein spots were changed, including 17 spots that were increased and 7 spots that were decreased. Ginsenoside Rg1 could restore the expression levels of these proteins, at least partly, to basic levels of untreated cells. The expression of G-protein coupled receptor kinase, protein kinase C (PKC)-zeta, N-ras protein were decreased, while cycle related protein p21 was increased by ginsenoside Rg1 in TNF-alpha treated VSMC. CONCLUSION: PKC-zeta and p21 pathway might be the mechanism for inhibitory effects of ginsenoside Rg1 on proliferation of VSMC.     

Pentoxifylline inhibits tumor necrosis factor-alpha induced synthesis of complement component C3 in human endothelial cells

Vascular endothelium is a major target for the inflammatory damage that occurs with multiple organ dysfunction associated with sepsis and other trauma. The growing appreciation of endothelium as a target of inflammation has obscured the importance of these cells as a source of inflammatory mediators. In the following study we evaluated the ability of tumor necrosis factor-alpha (TNF) to induce the synthesis of complement component C3 in human umbilical vein endothelial cells (HUVEC) and whether pentoxifylline (PTX) could reduce C3 expression. Confluent monolayers of HUVEC were treated with increasing concentrations of TNF with and without two concentrations of PTX. Concentrations of C3 were determined every 48 h for 144 h in cellular supernatants and C3 mRNA was amplified using RT-PCR. TNF increased C3 release from HUVEC in a concentration dependent manner. PTX added at the same time as TNF significantly reduced C3 release at the 96 h time point. Consistent with data on C3 release PTX inhibited the increased C3 mRNA expression associated with TNF treatment. TNF increases C3 synthesis and release from endothelial cells which were inhibited by clinical concentrations of PTX. This data further supports the potential benefit of PTX in multiple organ dysfunction and other inflammatory processes involving the endothelium by inhibiting one of the major mediators of vascular damage.     

Suppression of mast cell-mediated allergic reaction by Amomum xanthiodes.

The mast cell-mediated immediate-type allergic reaction is involved in many allergic diseases such as asthma, allergic rhinitis and sinusitis. Stimulation of mast cells starts the process of degranulation resulting in release of mediators such as histamine and an array of inflammatory cytokines. In this report, we investigated the effect of aqueous extract of Amomum xanthiodes (Zingiberaceae) (AXE) on the mast cell-mediated allergy model and studied its possible mechanisms of action. AXE inhibited compound 48/80-induced systemic reactions and serum histamine release in mice. AXE decreased immunoglobulin E (IgE)-mediated passive cutaneous anaphylaxis reaction. AXE reduced histamine release and intracellular calcium from rat peritoneal mast cells activated by compound 48/80. Furthermore, AXE decreased the activation of p38 mitogen-activated protein kinase (MAPK) but not extracellular signal-regulated kinase and c-jun N-terminal kinase, and downstream tumor necrosis factor (TNF)-alpha production in phorbol 12-myristate 13-acetate and calcium ionophore A23187-stimulated human mast cells. Our findings provide evidence that AXE inhibits mast cell-derived allergic reactions, and that intracellular calcium, TNF-alpha, and p38 MAPK are involved in these effects.     

非诺贝特对高脂血症兔血清及脂肪细胞分泌肿瘤坏死因子-α的影响

目的　观察非诺贝特干预对高脂血症兔血清及脂肪细胞分泌肿瘤坏死因子 α(TNF α)的影响,并探讨其可能机制。方法　10只新西兰大白兔给予高胆固醇饮食饲养 8w后,随机分为两组:①高胆固醇组:继续饲以高胆固醇饲料wk;②非诺贝特组:在饲以高胆固醇饲料的基础上给予非诺贝特(30mg·kg-1·d-1 ),共 4wk。另选普通饮食 12wk兔(n=5)作为对照组。取腹股沟皮下脂肪组织称量,并行脂肪细胞培养,酶联免疫吸附法 (ELISA)检测血清及脂肪细胞培养液中TNF α水平。半定量逆转录多聚酶链式反应 (RT PCR)测定脂肪细胞PPARαmRNA的表达。结果　高胆固醇组血清总胆固醇、低密度脂蛋白胆固醇水平明显高于对照组(P<0 01),非诺贝特干预 4wk未对血脂产生明显影响,但能降低体重 ( -19% )及皮下脂肪量 ( -40% ),并能降低血清TNF α水平 ( -44 7%,与高胆固醇组比,P<0 05 )。非诺贝特呈剂量依赖性降低脂肪细胞分泌TNF α。三组兔脂肪细胞PPARαmRNA表达差异无显著性。结论　非诺贝特能独立于降脂作用外降低高胆固醇饮食饲养兔体重和皮下脂肪量并降低血清及脂肪细胞分泌TNF α,这一作用可能有利于动脉粥样硬化及肥胖的防治。     

Justicidin A inhibits the transport of tumor necrosis factor-alpha to cell surface in lipopolysaccharide-stimulated RAW 264.7 macrophages

Exposure of macrophages to lipopolysaccharide (LPS) induces release of tumor necrosis factor-alpha (TNF-alpha), which is initially synthesized as a 26-kDa pro-TNF-alpha followed by proteolytic processing to a 17-kDa secreted form. In this study, justicidin A, an arylnaphthalide lignan isolated from Justicia procumbens, was found to inhibit LPS-stimulated TNF-alpha release from RAW 264.7 macrophages in a concentration- and time-dependent manner, and the underlying mechanism was investigated. In the presence of justicidin A, challenge with LPS increased the steady-state level of the 26-kDa membrane-bound form of TNF-alpha protein, whereas justicidin A had little effect on the expression of TNF-alpha mRNA and on the synthesis of pro-TNF-alpha protein. Results of the pulse-chase experiment, revealed that the conversion of pro-TNF-alpha to mature TNF-alpha was inhibited by justicidin A. Moreover, justicidin A suppressed the transport of TNF-alpha to cell surface as analyzed by flow cytometry. The immunofluorescence analysis demonstrated that large amounts of LPS-induced TNF-alpha accumulated primarily within Golgi complex. These results indicate that justicidin A inhibits TNF-alpha release at the step of transport of pro-TNF-alpha to cell surface, and this leads to the accumulation of TNF-alpha in Golgi complex in RAW 264.7 macrophages.     

Natural inhibitors of tumour necrosis factor-alpha production, secretion and function

Tumour necrosis factor-alpha (TNF), originally discovered by its antitumor activity, is one of the most pleotropic cytokines acting as a host defence factor in immunologic and inflammatory responses. Although the antitumour activity and mediation of inflammation by TNF could be beneficial to the host, unregulated TNF is now known to be the basis for development of various diseases including septic shock, the wasting disease, cachexia, and various inflammatory and/or autoimmune diseases. With an attempt to find potential therapeutic agents for TNF-mediated diseases, research during the last decade has led in the identification of well over one hundred natural inhibitors of either TNF production/secretion or function. This review summarises the structures, mechanism of action and therapeutic potential of these natural products.     

Modulation of tumor necrosis factor-alpha production with anti-hypertensive drugs

It is well known that some anti-hypertensive drugs affect insulin sensitivity and that tumor necrosis factor-alpha (TNF-alpha) is a mediator of obesity-associated insulin resistance. In this study, we have investigated the effect of anti-hypertensive drugs, calcium (Ca) channel blockers (amlodipine, manidipine and nicardipine), an alpha(1)-blocker (doxazosin), a beta(1)-blocker (metoprolol), and a thiazide diuretic (hydrochlorothiazide), on lipopolysaccharide (LPS)-induced TNF-alpha production. TNF-alpha production, measured with a bioassay and an immunoassay, was evaluated both in vivo and in vitro, by utilizing mice and a human peripheral blood mononuclear cell culture, respectively. Nicardipine, or amlodipine, manidipine and doxazosin significantly inhibited TNF-alpha production in mice at doses more than one or ten times higher than those used clinically, respectively. On the other hand, metoprolol increased TNF-alpha production at doses of more than 10 times those used clinically, whereas hydrochlorothiazide did not alter production of the cytokine. The in vivo effects of these drugs were not necessary parallel to the in vitro effects. Because high doses of these drugs in mice correspond to clinical doses and effects in human, these actions may be related to beneficial and/or harmful effects of these drugs on TNF-alpha mediated diseases, including insulin resistance.     

ELISA for quantitation of tumor necrosis factor-alpha in serum

A sensitive and precise ELISA has been developed for the quantitation of recombinant Tumor Necrosis Factor-Alpha (rTNF-alpha) in undiluted sera. Affinity purified rabbit antibody was used as capture antibody and mouse monoclonal antibody labelled with horseradish peroxidase was used as the second antibody in a sandwich ELISA. The assay range was from 50 to 2000 pg/ml and the relative standard deviation was 8% or less for both interassay and intra-assay precision studies. Recovery of rTNF-alpha added to 10 different human and 10 different monkey sera ranged from 81 to 102% and 100 to 120% of the expected value, respectively. This ELISA has been used to measure serum rTNF-alpha levels in over 60 patients in Phase I Clinical Trials treated with rTNF-alpha. The levels in a representative, pharmacokinetic study showed low variability between 8 patients receiving intravenous bolus administration of 100 mu rTNF-alpha/m(2). The ELISA results correlated well with TNF bioassay data with a mean specific activity of 2.5 x 10(7) U/mg.     

Targeting tumor necrosis factor-alpha in the therapy of psoriasis

Tumor necrosis factor-alpha (TNF-alpha) plays a fundamental role in the initiation and persistence of skin inflammation in psoriasis. The best evidence of the essential activity of this cytokine in the pathogenesis of psoriasis came from the observation that selective TNF-alpha blockers are dramatically effective in the therapy of this disease. The TNF-alpha inhibitors, infliximab and etanercept, have been employed with success in moderate to severe psoriasis and in psoriatic arthritis in randomized controlled trials. Anti-TNF-alpha biologicals induce rapid disease resolution and long-lasting remission, suggesting that they may alter the natural course of the disease. Further studies are warranted to more precisely establish the biological bases of the action of anti-TNF-alpha agents, better define which subgroup of patients can benefit most from this treatment, and the modalities of combination therapy with other antipsoriatic agents. Many other TNF-alpha inhibitors have been developed but none of them has been yet used in the therapy of psoriasis. Major limitations to the use of selective TNF-alpha blockers include the reactivation of latent tuberculosis, the risk of opportunistic infections, the development of specific antibodies, which is associated with a reduced duration of response to treatment, and the high cost.