LPS-stimulated TNF-alpha Production Research Articles

Analysis of immune response of stressed male mice during Chlamydia muridarum lung infection

Chlamydia lung infection caused by Chlamydia trachomatis is a serious lung infection particularly in infants but there are a few studies about lung infection. Chlamydial genital and lung infections in mice is frequently done with Chlamydia muridarum. The purpose of our study was to explore the effect of stress in lung chlamydia infection in male mice. We hypothesize that stress changes the level of cytokine production in monocytes during lung infection. As a The result from these studies include counting of live cells, differentiation of proliferation of bone marrow derived monocytes where the result showed that non-stressed dendritic cells (DCs) WT mice and stressed macrophages (MO) WT mice had sufficient live cells to study. No difference in IL-b production of macrophages of stressed and non-stress mice was observed. Beta2-adrenergic receptor (b2-AR agonist (fenoterol) and antagonist (ICI 118 551) treatment resulted in difference in cytokine production the effect of agonists and antagonists. TNF-alpha production was high in stressed mice compared to non-stress mice for MO. LPS stimulated TNF-alpha production in DC but showed no difference in stressed and non-stressed mice. However, TNF-alpha production in macrophages of non-stressed mice was decreased. The production of IFN-g, in Con A- and LPS-treated splenic T cells. In contrast IL-5, IL-10, and IL-23 production was high in T cells of stressed mice. T cells treated with norepinephrine and bet2-adrenergic receptor agonist, Fenoterol. Overall, the production of cytokines in stressed and non-stressed mice shows variation that may have roles in enhancing protection or increased lung infection.

Locally injected ivabradine inhibits carrageenan-induced pain and inflammatory responses via hyperpolarization-activated cyclic nucleotide-gated (HCN) channels.

BackgroundRecently, attention has been focused on the role of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in the mechanism of and as a treatment target for neuropathic and inflammatory pain. Ivabradine, a blocker of HCN channels, was demonstrated to have an effect on neuropathic pain in an animal model. Therefore, in the present study, we evaluated the effect of ivabradine on inflammatory pain, and under the hypothesis that ivabradine can directly influence inflammatory responses, we investigated its effect in in vivo and in vitro studies.MethodsAfter approval from our institution, we studied male Sprague–Dawley rats aged 8 weeks. Peripheral inflammation was induced by the subcutaneous injection of carrageenan into the hindpaw of rats. The paw-withdrawal threshold (pain threshold) was evaluated by applying mechanical stimulation to the injected site with von Frey filaments. Ivabradine was subcutaneously injected, combined with carrageenan, and its effect on the pain threshold was evaluated. In addition, we evaluated the effects of ivabradine on the accumulation of leukocytes and TNF-alpha expression in the injected area of rats. Furthermore, we investigated the effects of ivabradine on LPS-stimulated production of TNF-alpha in incubated mouse macrophage-like cells.ResultsThe addition of ivabradine to carrageenan increased the pain threshold lowered by carrageenan injection. Both lamotrigine and forskolin, activators of HCN channels, significantly reversed the inhibitory effect of ivabradine on the pain threshold. Ivabradine inhibited the carrageenan-induced accumulation of leukocytes and TNF-alpha expression in the injected area. Furthermore, ivabradine significantly inhibited LPS-stimulated production of TNF-alpha in the incubated cells.ConclusionThe results of the present study demonstrated that locally injected ivabradine is effective against carrageenan-induced inflammatory pain via HCN channels. Its effect was considered to involve not only an action on peripheral nerves but also an anti-inflammatory effect.

Abstract # 1820 Stimulated cytokine production is heightened among pregnant women carrying female versus male fetuses

Fetal sex plays a role in regulating maternal adaptation across pregnancy including glycemic control, blood pressure, and cortisol. However, data examining effects of fetal sex on maternal immune parameters is lacking, despite observed differences in maternal health responses and pregnancy outcomes in relation to fetal sex. In the current study, serum levels of IL-6, IL-8, and TNF-alpha as well as LPS-stimulated production of IL-6, IL-8, TNF-alpha, and IL-1 beta by PBMCs incubated for 24 h were assessed during each trimester of pregnancy in 80 women (46 with male and 34 with female fetuses). Linear mixed models showed that women carrying females versus males exhibited heightened stimulated production of IL-6 during each trimester (ps 0.85). In conclusion, in pregnant women, those carrying female versus male fetuses exhibit greater stimulated cytokine production. Heightened inflammation could affect maternal health and fetal development. Fetal sex should be considered as a factor in studies of maternal inflammation. Future investigations focused on women with health conditions (e.g., preeclampsia) and adverse pregnancy outcomes (e.g., preterm birth) would be informative.

47. Differing trafficking and TNF-alpha production by monocyte subsets under adrenergic activation: Blunted mobilization of “pro-inflammatory” monocytes in individuals with elevated blood pressure

Elevated blood pressure (BP) and infiltration of the vasculature by monocytes contribute to vascular pathology; but, monocyte migratory characteristics based on differing inflammatory potential under adrenergic activation remains unclear. We compared “non-classical” (CD16++CD14+), “intermediate” (CD16+CD14++), and “classical” (CD16-CD14++) monocyte trafficking and their LPS-stimulated TNF-alpha production in response to a physical stressor (20-min treadmill exercise at 65–70% VO2peak) in participants ( n = 77) with high pre-hypertension (PHT), mild PHT or normal BP (NBP). To determine adrenergic receptor sensitivity, pre-exercise cells were also treated with isoproterenol (Iso) before LPS stimulation. Monocyte subpopulations and intracellular TNF-alpha production were evaluated by flow cytometry. Epinephrine and norepinephrine levels were significantly elevated during exercise. Overall, % non-classical monocytes increased, % intermediate did not change, whereas % classical decreased post-exercise ( p < .001). However, the % increase in non-classical monocytes under adrenergic activation was blunted in PHT individuals ( p < .05). TNF-alpha production in all subsets decreased post-exercise and with in-vitro Iso treatment, irrespective of BP ( p < .001), with nonclassical and intermediate monocytes being a major source of TNF-alpha production. These findings extend our previous reports by showing that the mobilization of “pro-inflammatory” monocytes under sympathoadrenal activation is attenuated with even mild BP elevation. This may be indicative of monocytic adrenergic receptor desensitization and/or greater adhesion of “pro-inflammatory” monocytes to the vascular endothelium in hypertension with clinical implications of vascular pathology.

Resistance Training at Eight-Repetition Maximum Reduces the Inflammatory Milieu in Elderly Women

Inflammatory cytokines are associated with age- and inactivity-related diseases. We examined the influence of moderate- to high-intensity resistance trainings (RT) on inflammatory cytokines (interleukin 6 (IL-6) and 1beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha)) in circulation and lipopolysaccharide (LPS)-stimulated whole blood in elderly women. Previously sedentary women (72 +/- 6.1 yr) were grouped according to their hormone replacement regimen: traditional estrogen/progesterone (HRT, n = 12), selective estrogen receptor modulator (SER, n = 7), no hormone replacement (NHR, n = 9), or nonexercise control group taking no hormone replacement (CON, n = 7). Participants in the HRT, SER, and NHR groups trained (three sets, 10 exercises at eight-repetition maximum (8RM)) 3 d x wk(-1), whereas participants in the CON group maintained their "normal" activity for 10 wk. Participants performed a bout of resistance exercise (RE at 8RM; HRT, SER, and NHR groups) or sat quietly (CON) before (BT) and after (AT) RT to assess the influence of training on the acute responses to RE. Blood samples were obtained preexercise (PR), postexercise (PO), and 2 h postexercise (2H; same time points for resting CON). Hormone status had no influence on dependent variables, so HRT, SER, and NHR groups were collapsed into one exercise group (EX, n = 28) and compared with CON. RT significantly reduced resting serum TNF-alpha level by 37%. RT also reduced LPS-stimulated production of IL-6, IL-1beta, and TNF-alpha at all time points (PR, PO, and 2H; per monocyte). Acute RE transiently increased plasma TNF-alpha, but blunted the circadian increase in LPS-stimulated inflammatory cytokines observed in CON. The blunting effect in EX was significantly greater AT compared with BT. RE also resulted in an increase in plasma IL-6, which was significantly reduced AT (BT: PR = 1.6 +/- 0.5, PO = 2.8 +/- 0.5; AT: PR = 1.8 +/- 0.3, PO = 2.4 +/- 0.3). We found that 10 wk of moderate- to high-intensity RT 1) reduced the systemic inflammatory milieu and 2) abrogated exercise-induced circulating IL-6 in previously sedentary elderly women.

Antioxidant Supplementation Alters Cytokine Production From Monocytes

We studied in 10 healthy subjects the effect of chronic enteral supplementation of antioxidants (vitamins E, C, A, allopurinol, and N-acetylcysteine) on cytokine production by monocytes at rest, end exercise (60-min cycling at 60% of maximum oxygen consumption), and 60 min post-exercise (recovery). The percentage and the mean fluorescent intensity (MFI) of both unstimulated and lipopolysaccharide (LPS)-stimulated tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6-producing monocytes were detected using flow cytometry. Antioxidants decreased the percentage of unstimulated IL-6-producing monocytes following exercise, while their MFI increased at rest. The percentage of LPS-stimulated monocytes increased after exercise and they produced more IL-6 both at rest and following exercise. The percentage of unstimulated and LPS-stimulated IL-1beta-producing monocytes was not affected by antioxidants. The MFI of IL-1beta-produced unstimulated monocytes was increased after antioxidants both at rest and following exercise. After antioxidants, LPS-stimulated monocytes produced more IL-1beta following exercise. Antioxidants decreased the percentage of TNF-alpha spontaneously-produced monocytes following exercise, which produced more TNF-alpha at recovery. Antioxidants did not affect the percentage of LPS-stimulated monocytes producing TNF-alpha, while LPS-stimulated production of TNF-alpha increased both at rest and following exercise. Antioxidants differentially affect TNF-alpha, IL-1beta, and IL-6 production by monocytes, with a general tendency of augmenting cytokine production.

META060 inhibits multiple kinases in the NF-κB pathway and suppresses LPS – mediated inflammation in vitro and ex vivo

We investigated whether a novel candidate META060 targeted the inflammatory signal transduction without affecting constitutive COX-2 enzymatic activity in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. We also investigated its bioavailability in humans and its anti-inflammatory effect ex vivo. We measured prostaglandin E(2), nitric oxide, TNFalpha and IL-6 by ELISA, COX-2 protein by Western blot, NF-kappaB nuclear binding by electrophoretic mobility shift assays, and NF-kappaB activation by luciferase assay. Kinase inhibitions were measured by cell-free assays. Bioavailability was tested in 4 human subjects consuming 940 mg META060. LPS-activated TNFalpha and IL-6 were measured in peripheral blood mononuclear cells (PBMC) isolated from 1 subject up to 6 hours post administration. META060 dose-dependently inhibited prostaglandin E(2) and nitric oxide formation, COX-2 abundance, and NF-kappaB activation. In cell-free assays, META060 inhibited multiple kinases in the NF-kappaB signaling pathway, including BTK, PI3K, and GSK3. META060 was detected in the plasma of the subjects; isolated PBMC were resistant to LPS-stimulated TNFalpha and IL-6 production. Without inhibiting COX-2 enzyme, META060 reduces the inflammation by inhibiting multiple kinases involved in NF-kappaB pathway, and may have potential as a safe anti-inflammatory therapeutic.

Inhibition of Lipopolysaccharide-Stimulated Chronic Obstructive Pulmonary Disease Macrophage Inflammatory Gene Expression by Dexamethasone and the p38 Mitogen-Activated Protein Kinase Inhibitor N-cyano-N′-(2-{[8-(2,6-difluorophenyl)-4-(4-fluoro-2-methylphenyl)-7-oxo-7,8-dihydropyrido[2,3-d] pyrimidin-2-yl]amino}ethyl)guanidine (SB706504)

p38 mitogen-activated protein kinase (MAPK) signaling is known to be increased in chronic obstructive pulmonary disease (COPD) macrophages. We have studied the effects of the p38 MAPK inhibitor N-cyano-N'-(2-{[8-(2,6-difluorophenyl)-4-(4-fluoro-2-methylphenyl)-7-oxo-7,8-dihydropyrido[2,3-d]-pyrimidin-2-yl]amino}ethyl)guanidine (SB706504) and dexamethasone on COPD macrophage inflammatory gene expression and protein secretion. We also studied the effects of combined SB706504 and dexamethasone treatment. Lipopolysaccharide (LPS)-stimulated monocyte derived macrophages (MDMs) and alveolar macrophages (AMs) were cultured with dexamethasone and/or SB706504. MDMs were used for gene array and protein studies, whereas tumor necrosis factor (TNF) alpha protein production was measured from AMs. SB706504 caused transcriptional inhibition of a range of cytokines and chemokines in COPD MDMs. The use of SB706504 combined with dexamethasone caused greater suppression of gene expression (-8.90) compared with SB706504 alone (-2.04) or dexamethasone (-3.39). Twenty-three genes were insensitive to the effects of both drugs, including interleukin (IL)-1beta, IL-18, and chemokine (CC motif) ligand (CCL) 5. In addition, the chromosome 4 chemokine cluster members, CXCL1, CXCL2, CXCL3, and CXCL8, were all glucocorticoid-resistant. SB706504 significantly inhibited LPS-stimulated TNFalpha production from COPD and smoker AMs, with near-maximal suppression caused by combination treatment with dexamethasone. We conclude that SB706504 targets a subset of inflammatory macrophage genes and when used with dexamethasone causes effective suppression of these genes. SB706504 and dexamethasone had no effect on the transcription of a subset of LPS-regulated genes, including IL-1beta, IL-18, and CCL5, which are all known to be involved in the pathogenesis of COPD.

Acute Ethanol Exposure Attenuates Pattern Recognition Receptor Activated Macrophage Functions

Both clinical and experimental data have linked acute ethanol exposure to increased susceptibility to infection as well as increased morbidity and mortality after injury. Macrophages play an integral role in the innate immune system and are important in priming the adaptive immune system. In this study, we investigated the effect of a single in vivo exposure of macrophages to physiologically relevant levels of ethanol (1.2 and 2.9 g/kg) followed by ex vivo stimulation with lipopolysaccharide (LPS) or bacteria. Our study confirms the work of others showing that a single administration of ethanol suppresses the production of tumor necrosis factor-alpha(TNF-alpha), interleukin-6 (IL-6), and IL-12 in response to LPS. There was no effect of ethanol on LPS induction of cytokine production at 30 min after treatment. In contrast, at 3 h, both doses of ethanol exposure decreased ex vivo TNF-alpha production by splenic and alveolar macrophages. Interestingly, the higher dose of ethanol resulted in sustained suppression of LPS-induced TNF-alpha production at 3 and 6 h after ethanol administration, as well as decreased IL-6 and IL-12 production after 6 h, as compared to control (saline-treated groups). Alveolar macrophages behaved similarly at 3 h after ethanol treatment. LPS-stimulated production of TNF-alpha and IL-6 was reduced at 3 h after ethanol administration, when compared with the saline-treated animals. Alveolar macrophages stimulated for 3 h with bacteria also showed decreased TNF-alpha and IL-6 production after harvested from mice given 2.9 g/kg ethanol for 3 h. This time point and high dose of ethanol also resulted in decreased Pseudomonas aeruginosa phagocytosis by alveolar macrophages. Taken together, we conclude that the effects of physiological levels of ethanol are dose dependent, have effects that last after ethanol is cleared from the circulation, and can affect multiple macrophage functions.

Mechanisms for the anti‐inflammatory effects of adiponectin in macrophages

Adiponectin is an adipokine with potent anti-inflammatory properties. The development of alcoholic liver disease is thought to involve increased pro-inflammatory activity, mediated in part by the activation of hepatic macrophages (Kupffer cells). Chronic ethanol feeding sensitizes hepatic macrophages to activation by lipopolysaccharide (LPS), leading to increased production of reactive oxygen species and tumor necrosis factor-alpha (TNF-alpha). Adiponectin can normalize Toll-like receptor-4 (TLR-4) mediated signaling in hepatic macrophages after ethanol feeding, likely contributing to the hepatoprotective effect of adiponectin in the progression of alcoholic liver disease. However, the mechanisms by which adiponectin suppress TLR-4 mediated responses are not well understood. Using the macrophage-like cell line, RAW264.7, we have investigated the molecular mechanisms by which adiponectin suppresses LPS-stimulated TNF-alpha production. Globular adiponectin (gAcrp)-mediated desensitization of LPS-stimulated responses in RAW264.7 macrophages was dependent on the production of the anti-inflammatory cytokine interleukin (IL)-10. gAcrp initially increased TNF-alpha expression in RAW264.7 macrophages; this TNF-alpha then contributed to increased expression of IL-10. This initial gAcrp-mediated increase in TNF-alpha production by macrophages was mediated via activation of ERK1/2-->Egr-1 and nuclear factor (NF)-kappaB-dependent mechanisms. gAcrp-stimulated IL-10 expression was also dependent on the phosphorylation of cAMP response element-binding protein and the cAMP response element in the IL-10 promoter. In summary, these studies reveal a complex, integrated response of macrophages to gAcrp. gAcrp initially activated signaling pathways considered to be pro-inflammatory, with a subsequent increase in the expression of the potent, anti-inflammatory cytokine, IL-10. Increased IL-10 expression was ultimately required for the suppression of TLR4-mediated signaling by gAcrp.

Monocyte Major Histocompatibility Complex Class II Expression in Term and Preterm Labor

To investigate how term and preterm labor (PTL) influence the balance between maternal proinflammatory and antiinflammatory responses as measured by expression of major histocompatibility complex (MHC) Class II on maternal monocytes and tumor necrosis factor-alpha (TNF-alpha) production by in vitro stimulation of whole blood by lipopolysaccharide (LPS). Blood was taken from the following women (n=118): term elective cesarean delivery or in spontaneous labor, in premature labor, or with preterm premature rupture of the membranes (PROM) at less than 32 weeks, and gestation-matched reference group. Monocyte MHC Class II expression was measured by flow cytometry using a dual-staining technique. Plasma cytokine levels were assayed using a cytometric bead array system. In vitro whole blood stimulation with LPS was also performed, and cytokine production was measured. Term labor was associated with a fall in the percentage of monocytes expressing MHC Class II, compared with third trimester of pregnancy, P<.05 and a reduction in LPS-stimulated TNF-alpha production. This fall in MHC Class II was even more pronounced in PTL and preterm PROM groups compared with the reference group, P<.01. There was evidence of reduced expression of monocyte MHC Class II and LPS-stimulated TNF-alpha in term and preterm labor. This pattern of reduced MHC Class II expression and reduced TNF-alpha production is known as monocyte hyporesponsiveness or immune paresis. Detection of this state may provide insights into the maternal inflammatory status and be of use in the management of women with threatened PTL or preterm PROM. II.

Effect of Methyl Derivatives of Dopamine on Tumor Necrosis Factor α and Lipid Peroxidation

We recently demonstrated that melatonin, N-acetylserotonin (NAS), and N-acetyldopamine (NAD) attenuate the synthesis of lipopolysaccharide (LPS)-stimulated tumor necrosis factor-alpha (TNF-alpha) and the generation of oxidant radicals. In this study, we examined whether acetyl and methyl derivatives of dopamine modulate LPS-stimulated TNF-alpha synthesis and LPS- and iron-induced lipid peroxidation. Differentiated THP-1-derived human monocytes were coincubated with Escherichia coli and rising concentrations of NAS, NAD, N-methyldopamine (NMD), or 4-O-methyldopamine (4-O-MD). After 24 h, TNF-alpha was measured in cell supernatants. In addition, lipid peroxidation was induced by adding FeCl(2) solution to mouse brain tissue homogenates in the presence of rising concentrations of NAS, NAD, NMD, or 4-O-MD. Incubating THP-1-derived monocytes with rising concentrations of NAS, NAD, NMD, or 4-O-MD markedly decreased LPS-stimulated TNF-alpha production, which was dose dependent and on the order of 96%-98%. Rising concentrations of NMD markedly inhibited lipid peroxidation by 59%-98%. Our results indicated that the inhibitory effect of NAS, NAD, NMD, or 4-O-MD on LPS-induced TNF-alpha production and FeCl(2)-stimulated lipid peroxidation is robust and dose dependent.

Effect of A2B Adenosine Receptor Gene Ablation on Adenosine-Dependent Regulation of Proinflammatory Cytokines

Pharmacological studies suggest that A(2B) adenosine receptors mediate proinflammatory effects of adenosine. This concept was recently challenged by the finding that A(2B) adenosine receptor knockout (A(2B)KO) mice had moderate inflammation due to elevated basal plasma tumor necrosis factor (TNF)-alpha and an exaggerated response to lipopolysaccharide (LPS) challenge. However, it is unclear whether this phenomenon actually reflects the loss of putative taming of proinflammatory cytokine production via activation of A(2B) receptors by endogenous adenosine. In this report, we examined adenosine receptor-dependent regulation of interleukin (IL)-6 and TNF-alpha blood plasma levels in A(2B)KO and wild-type mice in vivo and their release from peritoneal macrophages ex vivo. Stimulation of adenosine receptors with 5'-N-ethylcarboxamidoadenosine (NECA) up-regulated IL-6 and suppressed LPS-induced TNF-alpha in wild-type mice. The selective A(2B) antagonists 3-isobutyl-8-pyrrolidinoxanthine and 8-[4-[((4-cyanophenyl)carbamoylmethyl)oxy]phenyl]-1,3-di(n-propyl)xanthine (MRS 1754) inhibited NECA-induced IL-6 release but not the suppression of LPS-induced TNF-alpha secretion from macrophages. Genetic ablation of A(2B) receptors abrogated NECA-induced increases in IL-6 release from mouse peritoneal macrophages and dramatically reduced the ability of NECA to raise IL-6 plasma levels in vivo. In contrast, the absence of A(2B) adenosine receptors did not affect NECA-induced suppression of LPS-activated TNF-alpha release in macrophages, nor did it reduce the ability of NECA to suppress LPS-induced increase in TNF-alpha plasma levels in vivo. Thus, our results indicate that stimulation of A(2B) receptors up-regulates the proinflammatory cytokine IL-6 and argue against the recently suggested anti-inflammatory role of A(2B) receptors in suppression of LPS-stimulated TNF-alpha production by adenosine.

Inflammation pro-resolving potential of 3,4-dihydroxyacetophenone through 15-deoxy-Δ 12,14-prostaglandin J 2 in murine macrophages

3,4-dihydroxyacetophenone (DHAP), an active component isolated from leaves of Tumaodongqing (Ilex Pubescens Hook. Et Arn. Var glaber Chang), is initially used to treat cardiovascular diseases. Previously, we found it had anti-inflammatory effect on macrophages by reducing the production of TNF-alpha in vitro. To further determine whether DHAP could influence inflammatory resolution, 15-deoxy-Delta(12,14)-prostaglandin J(2) (15dPGJ(2)), an arachidonic acid metabolite and also crucial pro-resolving mediator in inflammation, was chosen as the research target. It showed that 10(-5) M DHAP resulted in obvious increase of 15dPGJ(2) in LPS-activated macrophages. Further, inflammation related cytokines and cell apoptosis were also studied. We found DHAP could markedly inhibit LPS-stimulated production of TNF-alpha. However, it could not change the level of IL-10 obviously. At the same time, LPS-triggered apoptosis of macrophage was enhanced by DHAP significantly. After different kinds of cyclooxygenase (COX) inhibitors were administrated, it showed that the effects of DHAP on TNF-alpha and apoptosis were COX-2 dependent. While, inhibition of both COX-1 and COX-2 with indomethacin and administration of 15dPGJ(2) simultaneous reserved the effect of DHAP to inhibit TNF-alpha and enhance apoptosis in LPS-activated macrophages at least partly. The level of COX-2 mRNA and protein were also detected. It was showed that DHAP could increase the expression of COX-2 at both mRNA and protein levels in LPS-activated macrophages. Our results suggest that DHAP could accelerate resolution phase of acute inflammation though enhance the production of 15dPGJ(2), which was also proved to mediate the function of DHAP to inhibit TNF-alpha and enhance apoptosis in vitro. These results are potentially valuable for future use of DHAP.

Effects of Pentoxifylline on TNF-α Production by Peripheral Blood Mononuclear Cells in Patients with Nonalcoholic Steatohepatitis

Pentoxifylline (POF) is a new candidate for the treatment of nonalcoholic steatohepatitis (NASH). Its effects on the cytokine production in patients with NASH are not completely understood. This study was designed to investigate the effect of POF on TNF-alpha production by peripheral blood mononuclear cells (PBMC) in patients with NASH. After preliminary experiments in healthy control subjects to determine the range of POF concentration to be used in NASH patients, PBMCs from patients with NASH (n = 13) were cultured in the presence of lipopolysaccharide (LPS, 100 ng/ml) and various concentrations of POF for 24 hr. Concentrations of TNF-alpha in culture supernatants were measured by ELISA and the transcriptional activity was determined by RT-PCR. As dictated by the results of our preliminary study in PBMC from healthy control subjects, we treated LPS stimulated PBMCs from NASH patients with 10, 100, and 500 microg/ml of POF. Stimulation of PBMCs from NASH patients with LPS resulted in a strong up-regulation of TNF-alpha production from median 355.9 (interquartile range, 206.7-463.5) pg/ml to 1,670 pg/ml (interquartile range, 1,121-2,414) pg/ml. In this LPS-stimulated culture system, POF caused a dose-dependent suppression of TNF-alpha levels (P < 0.001, ANOVA on ranks for repeated measures). TNF-alpha levels in culture supernatants decreased to 870.3 (range, 598.3-2,077) pg/ml with 10 microg/ml of POF treatment, and to levels similar to those obtained in baseline unstimulated cultures (133.4 (range, 95.8-1518.5) pg/ml) at 100 microg/ml. At 500 microg/ml, POF suppressed TNF-alpha production to levels significantly lower than that obtained in unstimulated (baseline) culture supernatants (76.3 (range, 33-94.5) pg/ml; P = 0.001). The mRNA expression was consistent with the effects on protein concentration. Demographic characteristics of the patients, laboratory results, such as AST, ALT, alkaline phosphatase, GGT, and triglyceride levels, and the liver histology did not seem to influence the in vitro TNF-alpha response of the PBMCs from NASH patients. POF can significantly decrease the LPS-stimulated TNF-alpha production by PBMCs in NASH patients. Our results support the notion that POF might be a good candidate for the treatment of NASH.

Laparoscopic surgery and the parasympathetic nervous system

Laparoscopic surgery preserves the immune system and has anti-inflammatory properties. CO2 pneumoperitoneum attenuates lipopolysaccharide (LPS)-induced cytokine production and increases survival. We tested the hypothesis that CO2 pneumoperitoneum mediates its immunomodulatory properties via stimulation of the cholinergic pathway. In the first experiment, rats (n = 68) received atropine 1 mg/kg or saline injection 10 min prior to LPS injection and were randomization into four 30-min treatment subgroups: LPS only control, anesthesia control, CO2 pneumoperitoneum, and helium pneumoperitoneum. In a second experiment, rats (n = 40) received atropine 2 mg/kg or saline 10 min prior to randomization into the same four subgroups described previously. In a third experiment, rats (n = 96) received atropine 2 mg/kg or saline 10 min prior to randomization into eight 30-min treatment subgroups followed by LPS injection: LPS only control; anesthesia control; and CO2 or helium pneumoperitoneum at 4, 8, and 12 mmHg. In a fourth experiment, rats (n = 58) were subjected to bilateral subdiaphragmatic truncal vagotomy or sham operation. Two weeks postoperatively, animals were randomized into four 30-min treatment subgroups followed by LPS injection: LPS only control, anesthesia control, CO2 pneumoperitoneum, and helium pneumoperitoneum. Blood samples were collected from all animals 1.5 h after LPS injection, and cytokine levels were determined by enzyme-linked immunosorbent assay. Serum tumor necrosis factor-alpha (TNF-alpha) levels were consistently suppressed among the saline-CO2 pneumoperitoneum groups compared to saline-LPS only control groups (p < 0.05 for all four experiments). All chemically vagotomized animals had significantly reduced TNF-alpha levels compared to their saline-treated counterparts (p < 0.05 for all), except among the CO2 pneumoperitoneum-treated animals. Increasing insufflation pressure with helium eliminated differences (p < 0.05) in TNF-alpha production between saline- and atropine-treated groups but had no effect among CO2 pneumoperitoneum-treated animals. Finally, vagotomy (whether chemical or surgical) independently decreased LPS-stimulated TNF-alpha production in all four experiments. CO2 pneumoperitoneum modulates the immune system independent of the vagus nerve and the cholinergic pathway.

Immune‐Modulating Effects of Melatonin, N‐Acetylserotonin, and N‐Acetyldopamine

Melatonin and N-acetylserotonin (NAS) have antioxidant properties. In the present study, we examined whether melatonin, NAS, and N-acetyldopamine (NAD) have a modulatory effect on tumor necrosis factor-alpha (TNF-alpha) synthesis and superoxide production. Differentiated THP-1-derived human monocytes were coincubated with Escherichia coli lipopolysaccharide (LPS) and rising concentrations of melatonin, NAS, or NAD. After 24 h, TNF-alpha was measured in cell supernatants. In addition, the production of superoxide by HL-60-derived human neutrophils upon stimulation with 4-beta-phorbol 12-beta-myristate 13-alpha-acetate (PMA) or N-formyl methionyl-leucyl-phenylalanine (fMLP) and increasing concentrations of melatonin, NAS, or NAD was determined. Incubation of THP-1-derived monocytes with increasing concentrations of melatonin, NAS, or NAD resulted in a marked decrease in LPS-stimulated TNF-alpha production, which was dose-dependent and on the order of 96-98%. Incubation of HL-60-derived neutrophils with increasing concentrations of melatonin, NAS, or NAD resulted in a modest decrease in PMA-stimulated superoxide production, which was dose-dependent. At the 100 microM dose, melatonin, NAS, or NAD resulted in a 14 +/- 4%, 30 +/- 1%, and 29 +/- 1% decrease in PMA-stimulated superoxide production, respectively. Coincubation of HL-60 cells with melatonin, NAS, or NAD also resulted in a modest dose-dependent decrease in fMLP-stimulated superoxide production. At the 100 microM dose, melatonin, NAS, or NAD resulted in a 13 +/- 1%, 14 +/- 1%, and 14 +/- 1% decrease in superoxide production, respectively. Our results indicate that the inhibitory effect of melatonin, NAS, or NAD on LPS-induced TNF-alpha production is robust and dose-dependent. These compounds are equally effective in attenuating the generation of oxidant radicals, although to a lesser degree.

The non-thiol angiotensin-converting enzyme inhibitor quinapril suppresses inflammatory arthritis.

In addition to its vasoactive effects, angiotensin II has proinflammatory properties. Angiotensin-converting enzyme (ACE) inhibitors reduce the production of angiotensin II and could therefore act as anti-inflammatory agents. Here we investigated the capacity of the ACE inhibitor quinapril to modulate inflammatory arthritis. We studied the effect of quinapril on disease activity in mice with collagen-induced arthritis (CIA). Mice received oral quinapril (10 mg/kg/day) at the time of arthritis induction (prophylaxis protocol) or at the onset of mild arthritis (therapy protocol). Concentrations of immunoglobulin G (IgG) subtypes specific for bovine Type II collagen and TNF-alpha were measured by enzyme-linked immunoassay. Quinapril significantly diminished the activity of CIA when given as prophylaxis or therapy (prophylaxis protocol, P<0.001; therapy protocol P=0.002). Antigen-specific IgG2a antibodies were reduced by 52% (P=0.02) in the quinapril prophylaxis protocol. Suppression of arthritis by quinapril was associated with reduced articular expression of TNF-alpha by 68% (P=0.01) in the prophylaxis protocol and 27% (P=0.06) in the therapy protocol. Quinapril therapy also inhibited expression of splenocyte TNF-alpha production following lipopolysaccharide (LPS) in vitro stimulation by 59% (P=0.02). In parallel human in vitro experiments, ACE inhibition suppressed LPS-stimulated production of TNF-alpha by monocytes. In order to confirm that the action of quinapril occurred predominantly through suppression of angiotensin II, parallel experiments with the angiotensin receptor antagonist candesartan cilexetil demonstrated that this agent also inhibited disease activity in CIA. These data suggest that angiotensin II is a mediator of chronic inflammation and that ACE inhibition may have therapeutic effects in human inflammatory arthritis.

In vitro study of the potential role of guanidines in leukocyte functions related to atherogenesis and infection

The blunted immune response upon stimulation in chronic renal failure (CRF) is often coupled to a baseline inflammatory status which has been related to atherogenesis. Uremic biologic fluids and several specific uremic retention solutes alter cell-mediated immune responses, as well as the interaction of calcitriol with the immune system. The present study evaluated the influence of different guanidino compounds on DNA synthesis, chemiluminescence production, and CD14 expression of undifferentiated and calcitriol-differentiated HL-60 cells. In a second setup, these guanidino compounds were evaluated for their specific effect on normal human leukocyte oxidative burst activity and tumor necrosis factor-alpha (TNF-alpha) expression. First, several guanidino compounds elicited proinflammatory effects on leukocytes. Methylguanidine and guanidine stimulated the proliferation of undifferentiated HL-60 cells and the antiproliferative effect of calcitriol (P < 0.05) was neutralized in the presence of methylguanidine (P < 0.05) and guanidinosuccinic acid (P < 0.05). The phorbol-myristate-acetate (PMA)-stimulated chemiluminescence production of the calcitriol differentiated HL-60 cells was enhanced in the presence of guanidine (P < 0.05). Methylguanidine and guanidinoacetic acid enhanced the lipopolysaccharide (LPS)-stimulated intracellular production of TNF-alpha by normal human monocytes (P < 0.05). Second, several guanidino compounds inhibited the function of leukocytes if they were activated. The PMA-stimulated chemiluminescence production of the calcitriol differentiated HL-60 cells was inhibited by the presence of methylguanidine (P < 0.05), guanidinoacetic acid (P < 0.05) and guanidinosuccinic acid (P < 0.05). After incubation of whole blood in the presence of methylguanidine, the Escherichia coli stimulated oxidative burst activity of the granulocyte population was significantly inhibited (P < 0.05). In addition, guanidinosuccinic acid had an inhibitory effect on the LPS-stimulated intracellular production of TNF-alpha by human monocytes (P < 0.01). Guanidino compounds exert proinflammatory as well as anti-inflammatory effects on monocyte/macrophage function. This could contribute to the altered prevalence of cardiovascular disease and propensity to infection in patients with CRF.

The effect of high and low ambient temperatures on PGE2 and TNF-alpha production by rat glial brain cultures.

This study was undertaken to investigate the effect of changes in incubation temperature on PGE(2) and TNF-alpha production by rat glial brain cultures after LPS stimulation. One-hour incubation at temperatures of 4 degrees C, 37 degrees C, 39 degrees C and 42 degrees C were used. Treatment of cultures with 10 microg/ml LPS from Escherichia coli caused a significant elevation of PGE(2) production 24 h after incubation at control temperatures of 37 degrees C and the experimental temperatures of 4 degrees C, 39 degrees C and 42 degrees C. While high ambient temperatures of 39 degrees C and 42 degrees C reduced LPS-stimulated production, compared to exposure to 37 degrees C, exposure to 4 degrees C did not do so. On the other hand, exposure of the cultures to a temperature of 39 degrees C and 42 degrees C for 1 h did not alter LPS-stimulated TNF-alpha production, while exposure to a temperature of 4 degrees C significantly reduced this elevation.