Modulate Cytokine Release Research Articles

Time-dependent effects of ATP and its degradation products on inflammatory markers in human blood ex vivo

We recently reported that adenosine 5′-triphosphate (ATP) modulates cytokine release in lipopolysaccharide (LPS)-phytohemagglutinin (PHA)-stimulated blood. ATP inhibited tumor necrosis factor-alpha (TNF- α) release via activation of the P2Y 11 receptor and increased interleukin (IL)-10 release via stimulation of the P2Y 12 receptor. Because ATP is known to be broken down by various ecto-enzymes, we determined the degradation profile of ATP in time in LPS-PHA-stimulated blood. ATP slowly metabolized with 14% remaining after 6 h. Simultaneously, adenosine 5′-diphosphate (ADP), adenosine 5′-monophosphate (AMP) and hypoxanthine were formed. Subsequently, we investigated the time-dependent effects of ATP and its metabolites on inflammatory markers. Results showed that ATP decreased the rise in concentrations of TNF- α, interferon-gamma (IFN- γ) and IL-1 β, but increased concentrations of IL-8 and IL-10. Metabolites of ATP showed either no, similar or opposite effects on cytokine release, compared to ATP. In conclusion, ATP has rapid immunomodulatory effects on a variety of cytokines in stimulated whole blood that persist until 24 h.

Virodhamine and CP55,940 modulate cAMP production and IL‐8 release in human bronchial epithelial cells

We investigated expression of cannabinoid receptors and the effects of the endogenous cannabinoid virodhamine and the synthetic agonist CP55,940 on cAMP accumulation and interleukin-8 (IL-8) release in human bronchial epithelial cells. Human bronchial epithelial (16HBE14o(-)) cells were used. Total mRNA was isolated and cannabinoid receptor mRNAs were detected by RT-PCR. Expression of CB(1) and CB(2) receptor proteins was detected with Western blotting using receptor-specific antibodies. cAMP accumulation was measured by competitive radioligand binding assay. IL-8 release was measured by ELISA. CB(1) and CB(2) receptor mRNAs and proteins were found. Both agonists concentration-dependently decreased forskolin-induced cAMP accumulation. This effect was inhibited by the CB(2) receptor antagonist SR144528, and was sensitive to Pertussis toxin (PTX), suggesting the involvement of CB(2) receptors and G(i/o)-proteins. Cell pretreatment with PTX unmasked a stimulatory component, which was blocked by the CB(1) receptor antagonist SR141716A. CB(2) receptor-mediated inhibition of cAMP production by virodhamine and CP55,940 was paralleled by inhibition of tumor necrosis factor-alpha (TNF-alpha) induced IL-8 release. This inhibition was insensitive to SR141716A. In the absence of agonist, SR144528 by itself reduced TNF-alpha induced IL-8 release. Our results show for the first time that 16HBE14o(-) cells respond to virodhamine and CP55,940. CB(1) and CB(2) receptor subtypes mediated activation and inhibition of adenylyl cyclase, respectively. Stimulation of the dominant CB(2) receptor signalling pathway diminished cAMP accumulation and TNF-alpha-induced IL-8 release. These observations may imply that cannabinoids exert anti-inflammatory properties in airways by modulating cytokine release.

ATP-Depleting Carbohydrates Prevent Tumor Necrosis Factor Receptor 1-Dependent Apoptotic and Necrotic Liver Injury in Mice

We demonstrated previously that depletion of hepatic ATP by endogenous metabolic shunting of phosphate after fructose treatment renders hepatocytes resistant to tumor necrosis factor (TNF)-induced apoptosis. We here address the question whether this principle extends to TNF receptor 1-mediated caspase-independent apoptotic and to necrotic liver injury. As in the apoptotic model of galactosamine/lipopolysaccharide (LPS)-induced liver damage, the necrotic hepatotoxicity initiated by sole high-dose LPS treatment was abrogated after depletion of hepatic ATP. Although systemic TNF and interferon-gamma levels were suppressed, animals still were protected when ATP depletion was initiated after the peak of proinflammatory cytokines upon LPS injection, showing that fructose-induced ATP depletion affects both cytokine release and action. In T cell-dependent necrotic hepatotoxicity elicited by concanavalin A or galactosamine + staphylococcal enterotoxin B, ATP depletion prevented liver injury as well, but here without modulating cytokine release. By attenuating caspase-8 activation, ATP depletion of hepatocytes in vitro impaired TNF receptor signaling by the death-inducing signaling complex, whereas receptor internalization and nuclear factor-kappaB activation upon TNF stimulation were unaffected. These findings demonstrate that sufficient target cell ATP levels are required for the execution of both apoptotic and necrotic TNF-receptor 1-mediated liver cell death.

In vitro and in vivo activities of leukotriene B 4-loaded biodegradable microspheres

Leukotriene B 4 (LTB 4) is a potent inflammatory mediator and stimulates the immune response. In addition, LTB 4 promotes leukocyte functions such as phagocytosis, chemotaxis and chemokinesis of polymorphonuclear leukocytes, as well as modulates cytokine release. However, some physicochemical characteristics of leukotrienes, such as poor solubility in water and chemical instability, make them difficult to administer in vivo. The aim of this study was to develop LTB 4-loaded microspheres (MS) that prolong and sustain the in vivo release of this mediator. An oil-in-water emulsion solvent extraction–evaporation method was chosen to prepare the lipid-loaded MS. We determined their diameters, evaluated the in vitro release of LTB 4, using enzyme immunoassay and evaluated in vitro MS uptake by peritoneal macrophages. To assess the preservation of neutrophil chemoattractant activity, LTB 4-loaded MS were tested in vitro (in a modified Boyden microchamber) and in vivo, after intratracheal administration.

Low Doses of Dexamethasone Affect Immune Parameters in the Absence of Immunological Stimulation

Recent findings suggest an important role of subtle changes in the plasma levels of inflammatory cytokines within the brain-immune interplay. It is unclear how such changes are regulated in the absence of acute inflammatory or infectious stimuli. Endocrine systems are a good candidate, because innate immunity and the hypothalamo-pituitary-adrenal (HPA)-system are closely related: glucocorticoids have immunosuppressive properties and modulate cytokine release from stimulated mononuclear blood cells in vitro and the immune response in vivo, but it still remains unclear, whether they also modulate circulating cytokine levels in the absence of immunological stimuli. We measured the influence of 1.5 or 3.0 mg dexamethasone (DEX) per os at 09:00 or 21:00 hours on body temperature, cortisol plasma levels, differential white blood cell counts, and cytokine plasma levels in 40 healthy male volunteers using a double-blind, placebo-controlled study design. In addition to significant morning-evening differences in tympanic temperature and several immune parameters, we found that DEX-intake significantly increased tympanic temperature, decreased cortisol plasma levels, altered differential white blood cell counts and induced changes in unstimulated plasma cytokine levels. Whereas the levels of TNF-alpha and sTNF-R p75 were reduced, the levels of sTNF-R p55 increased after a transient decrease.

The pharmacology of cannabinoid receptors and their ligands: an overview

Mammalian tissues express at least two cannabinoid receptor types, CB1 and CB2, both G protein coupled. CB1 receptors are found predominantly at nerve terminals where they mediate inhibition of transmitter release. CB2 receptors occur mainly on immune cells, one of their roles being to modulate cytokine release. Endogenous agonists for cannabinoid receptors also exist, and are all eicosanoids. The first-discovered of these 'endocannabinoids' was arachidonoylethanolamide and there is convincing evidence that this ligand and some of its metabolites can activate vanilloid VRI (TRPV1) receptors. Certain cannabinoids also appear to have TRPV1-like and/or non-CB1, non-CB2, non-TRPV1 targets. Several CB1- and CB2-selective agonists and antagonists have been developed. Antagonists include the CB1-selective SR141716A, AM251, AM281 and LY320135, and the CB2-selective SR144528 and AM630. These all behave as inverse agonists, one indication that CB1 and CB2 receptors can exist in a constitutively active state. 'Neutral' cannabinoid receptor antagonists have also been developed. CB1 and/or CB2 receptor activation appears to ameliorate inflammatory and neuropathic pain and certain multiple sclerosis symptoms. This might be exploited clinically by using CB1, CB2 or CB1/CB2 agonists, or inhibitors of the membrane transport or catabolism of endocannabinoids that are released in increased amounts, at least in animal models of pain and multiple sclerosis. We have recently discovered the presence of an allosteric site on the CB1 receptor. Consequently, it may also prove possible to enhance 'autoprotective' effects of released endocannabinoids with CB1 allosteric enhancers or, indeed, to reduce proposed 'autoimpairing' effects of released endocannabinoids such as excessive food intake with CB1 allosteric antagonists.

Melanocortin receptor signaling in RAW264.7 macrophage cell line

Melanocortin peptides modulate cytokine release and adhesion molecule expression. Here we have investigated the early cell-signaling pathway responsible for the induction of interleukin-10 (IL-10) in RAW264.7 cells. Cell incubation with ACTH 1–39 or MTII (melanotan II) did not alter ERK1/2 and JNK phosphorylation, while p38 phosphorylation and intracellular cAMP accumulation occurred within minutes. ACTH 1–39 and MTII provoked a time-dependent accumulation of IL-10 that was abrogated by the PKA inhibitor H-89 and only partially blocked by the p38 MAPK inhibitor SB203580. Thus, in RAW264.7 cells, IL-10 induction by the melanocortins is via the PKA pathway, and this mechanism could contribute to their anti-inflammatory profile.

Leukotrienes modulate cytokine release from dendritic cells

Leukotriene B(4) (LTB(4)) and cysteinyl leukotrienes (CysLTs) are known as potent mediators of inflammation, whereas their role in the regulation of adaptive immunity remains poorly characterized. Dendritic cells (DCs) are specialized antigen-presenting cells, uniquely capable to initiate primary immune responses. We have found that zymosan, but not lipopolysaccharide (LPS) stimulates murine bone marrow-derived dendritic cells (BM-DCs) to produce large amounts of CysLTs and LTB(4) from endogenous substrates. A selective inhibitor of leukotriene synthesis MK886 as well as an antagonist of the high affinity LTB(4) receptor (BLT(1)) U-75302 slightly inhibited zymosan-, but not LPS-stimulated interleukin (IL)-10 release from BM-DCs. In contrast, U-75302 increased zymosan-stimulated release of IL-12 p40 by approximately 23%. Pre-treatment with transforming growth factor-beta1 enhanced both stimulated leukotriene synthesis and the inhibitory effect of U-75302 and MK886 on IL-10 release from DCs. Consistent with the effects of leukotriene antagonists, exogenous LTB(4) enhanced LPS-stimulated IL-10 release by approximately 39% and inhibited IL-12 p40 release by approximately 22%. Both effects were mediated by the BLT(1) receptor. Ligands of the high affinity CysLTs receptor (CysLT(1)), MK-571 and LTD(4) had little or no effect on cytokine release. Agonists of the nuclear LTB(4) receptor peroxisome proliferator-activated receptor-alpha, 8(S)-hydroxyeicosatetraenoic acid and 5,8,11,14-eicosatetraynoic acid, inhibited release of both IL-12 p40 and IL-10. Our results indicate that both autocrine and paracrine leukotrienes may modulate cytokine release from DCs, in a manner that is consistent with previously reported T helper 2-polarizing effects of leukotrienes.

The impact of eicosanoids on the crosstalk between innate and adaptive immunity: the key roles of dendritic cells

The innate immune response is essentially the first line of defense against an invading pathogen. Through specialized receptors, known as pattern recognition receptors, especially Toll-like receptors, specialized cells of myeloid origin, including macrophages and dendritic cells (DCs) are able to phagocytose microorganisms and induce an innate inflammatory response. Although B and T lymphocytes recognize tissue antigens with high specificity, they are unable to initiate immune responses. The decision to activate an appropriate immune response is made by unique DC, the most professional antigen-presenting cells (APCs) which control the responses of several types of lymphocytes and play central role in the transition between innate and adaptive immunity. Increased secretion of inflammatory endogenous mediators such as cytokines and arachidonic acid-derived lipid mediators, also termed eicosanoids, can activate APC, particularly DC, which in turn induce an adaptive immune response. There is an increasing evidence that eicosanoids play an important role in connecting innate and adaptive immunity by acting on cells of both systems. Prostanoids, a major class of eicosanoids, have a great impact on inflammatory and immune responses. PGE(2) is one of the best known and most well-characterized prostanoids in terms of immunomodulation. Although cytokines are known as key regulators of immunity, eicosanoids, including PGE(2), PGD(2), LTB(4), and LTC(4), may also affect cells of immune system by modulating cytokine release, cell differentiation, survival, migration, antigen presentation, and apoptosis. By acting on various aspects of immune and inflammatory reactions, these lipid mediators emerge as key regulators of the crosstalk between innate and adaptive immunity.

Fc receptor γ-chain activation via hOSCAR induces survival and maturation of dendritic cells and modulates Toll-like receptor responses

AbstractWe previously reported the characterization of human osteoclast-associated receptor (hOSCAR), a novel Fc receptor γ-chain (FcRγ)–associated receptor expressed by myeloid cells. Here we show that ligation of hOSCAR by specific antibodies promotes dendritic cell (DC) survival by an extracellular signal-regulated kinase (ERK)- and phosphatidylinositol 3-kinase (PI3K)–dependent pathway, linked to expression of the Bcl-2 and Bcl-xL antiapoptotic molecules. Crosslinking of hOSCAR leads to maturation of DCs, as demonstrated by up-regulation of maturation markers, decrease in dextran uptake capacity, and secretion of immunesystem effectors such as interleukin-8 (IL-8)/CXC chemokine ligand 8 (CXCL8), IL-12 p40, monocyte chemoattractant protein-1 (MCP-1)/chemokine receptor ligand 2 (CCL2) and macrophage-derived chemokine (MDC)/CCL22. Stimulation of hOSCAR acts in conjunction with the Toll-like receptor (TLR) ligands, lipopolysaccharide (LPS), R-848, and polyinosinic-polycytidylic acid (poly(I:C)), to increase the expression of maturation markers, and to modulate cytokine release. A PI3K-dependent up-regulation of IL-10 release is observed with all the TLR ligands used, whereas regulation of IL-12 production is variable depending on the TLR stimulated. hOSCAR engagement on DCs did not significantly increase the proliferation of naive T cells; however, when co-incubated with TLR ligands, an enhanced proliferation was observed. The percentage of interferon (IFN)–γ–producing T cells is decreased when hOSCAR engagement is combined with LPS stimulation. Altogether, these data suggest that hOSCAR may modulate the responses of both innate resistance and adaptive immunity.

Inverse agonism and neutral antagonism at cannabinoid CB 1 receptors

There are at least two types of cannabinoid receptor, CB 1 and CB 2, both G protein coupled. CB 1 receptors are expressed predominantly at nerve terminals and mediate inhibition of transmitter release whereas CB 2 receptors are found mainly on immune cells, one of their roles being to modulate cytokine release. Endogenous cannabinoid receptor agonists also exist and these “endocannabinoids” together with their receptors constitute the “endocannabinoid system”. These discoveries were followed by the development of a number of CB 1- and CB 2-selective antagonists that in some CB 1 or CB 2 receptor-containing systems also produce “inverse cannabimimetic effects”, effects opposite in direction from those produced by cannabinoid receptor agonists. This review focuses on the CB 1-selective antagonists, SR141716A, AM251, AM281 and LY320135, and discusses possible mechanisms by which these ligands produce their inverse effects: (1) competitive surmountable antagonism at CB 1 receptors of endogenously released endocannabinoids, (2) inverse agonism resulting from negative, possibly allosteric, modulation of the constitutive activity of CB 1 receptors in which CB 1 receptors are shifted from a constitutively active “on” state to one or more constitutively inactive “off” states and (3) CB 1 receptor-independent mechanisms, for example antagonism of endogenously released adenosine at A 1 receptors. Recently developed neutral competitive CB 1 receptor antagonists, which are expected to produce inverse effects through antagonism of endogenously released endocannabinoids but not by modulating CB 1 receptor constitutive activity, are also discussed. So too are possible clinical consequences of the production of inverse cannabimimetic effects, there being convincing evidence that released endocannabinoids can have “autoprotective” roles.

Modulatory Effects of l‐Carnitine on Glucocorticoid Receptor Activity

L-carnitine (3-hydroxy-4-N,N,N-trimethylaminobutyrate) is a conditionally essential nutrient with a major role in cellular energy metabolism. It is available in the United States as both a prescription drug and an over-the-counter nutritional supplement. Accumulating evidence from both animal and human studies indicates that pharmacologic doses of L-carnitine (LCAR) have immunomodulatory effects resembling those of glucocorticoids (GC). On the other hand, in contrast to GC, which cause bone loss, LCAR seems to have positive effects on bone metabolism. To explore the molecular bases of this GC-like activity of LCAR, we investigated its effects on glucocorticoid receptor (GR)-modulated cytokine release ex vivo, and on the transcriptional activity, intracellular trafficking, and binding of GR in vitro. At high noncytotoxic doses, LCAR (a) suppressed the lipopolysaccharide-stimulated release of tumor necrosis factor alpha and interleukin-12 from primary human monocytes in a GC-like fashion, (b) stimulated the transcriptional activity of GR on the GC-responsive promoters, (c) triggered nuclear translocation of green fluorescent protein (GFP)-fused GR, and (d) reduced the whole cell binding of [(3)H]-dexamethasone to GR. These results suggest that LCAR is a "nutritional modulator" of the GR, by acting as an agonist-like compound. Since LCAR appears to have positive effects on bone metabolism, in contrast to GC, LCAR may share some of the therapeutic properties of GC, particularly on the immune system, but not their deleterious side effects on some of other organs/tissues. Thus, LCAR is potentially a useful alternative compound of GC in particular therapeutic situations. The clinical and therapeutic implications of these findings, as well as a better understanding of their mechanisms, warrant further research.

Inverse agonism at cannabinoid receptors

There are at least two types of cannabinoid receptor, CB 1 and CB 2, both G protein coupled. CB 1 receptors are expressed predominantly at nerve terminals and mediate inhibition of transmitter release. CB 2 receptors are found mainly on immune cells, one of their roles being to modulate cytokine release. Endogenous ligands for these receptors (endocannabinoids) also exist. These discoveries have prompted the development of CB 1- and CB 2-selective agonists and antagonists. The latter include the CB 1-selective SR141716A and LY320135 and the CB 2-selective SR144528 and AM630, all of which appear to be inverse agonists. Indeed, antagonists without inverse agonist activity have yet to be developed. As most experiments directed at investigating inverse agonism at cannabinoid receptors have been performed with SR141716A, this review focusses on this agent. It presents evidence that the endocannabinoid system is tonically active and that this activity can stem both from ongoing release of endocannabinoids and from the presence of constitutively active CB 1 receptors. Thus, SR141716A seems to induce some inverse cannabimimetic effects by opposing responses to endogenously released endocannabinoids and other such effects by decreasing tonic activity induced by constitutively active CB 1 receptors. The interaction of SR141716A with constitutively active receptors is discussed in terms of “two-state” and “three-state” models.

Exogenous but not endogenous prostanoids regulate cytokine secretion from murine bone marrow dendritic cells: EP 2, DP, and IP but not EP 1, EP 3, and FP prostanoid receptors are involved

Murine bone marrow-derived dendritic cells (DC), stimulated with lipopolysaccharide (LPS) and/or LPS+interferon-γ (IFN-γ), secrete a variety of inflammatory mediators which may modulate their functions. We have examined the potential for exogenous prostanoids, acting in a paracrine fashion, and endogenous prostanoids, acting in an autocrine fashion, to regulate secretion of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-10, and IL-12 in DC. In order to identify receptors mediating these effects, DC were treated in vitro with receptor-selective prostanoids. Agonists of cyclic AMP-elevating receptors, namely, prostaglandin E 2 (PGE 2), butaprost (EP 2 receptor), iloprost (IP receptor), and BW245C (DP receptor), dose-dependently inhibited the release of IL-6, TNF-α, and IL-12 and enhanced the release of IL-10 from LPS-stimulated DC, with TNF-α secretion being the most strongly affected. In contrast, 15-deoxy-Δ 12,14-PGJ 2—an activator of nuclear peroxisome proliferator-activated receptor-γ (PPAR-γ) receptors—inhibited release of all tested cytokines. Exogenous prostanoids, cyclic AMP-elevating analogs, lost their ability to modulate cytokine release in cells pre-incubated for 4 h with LPS, indicating that prostanoids may affect DC functions during initial phases of LPS stimulation only. Sulprostone and (+)-fluprostenol failed to modulate any of responses tested, suggesting lack of involvement/expression of EP 1, EP 3, and FP receptors in DC activation. In order to examine the role of endogenous prostanoids, DC were treated with inhibitors of cyclooxygenases (COX). At concentrations that completely blocked PGE 2 release, neither indomethacin (nonselective inhibitor) nor rofecoxib (COX-2-selective inhibitor) influenced cytokine release from LPS-stimulated DC. Thus, cytokine release from LPS-stimulated DC does not seem to be autoregulated by endogenous prostanoids, whereas in vivo regulatory function may be fulfilled in a paracrine manner by PGD 2, PGE 2, and PGI 2 released from neighboring cells.

Differential modulation of interleukin‐6 and interleukin‐10 by diclofenac in patients undergoing major surgery

Prostaglandins modulate cytokine release though increases in cAMP, regulating interleukin (IL) 6 and IL-10. Diclofenac inhibits cyclo-oxygenase activity and hence prostaglandin production. We hypothesized that diclofenac would affect release of IL-6 and IL-10 and modulate the immune response. In a randomized, double-blind, placebo-controlled study, we investigated the effect of diclofenac in patients undergoing major urological surgery. Patients were randomized to receive either diclofenac (50 mg orally every 8 h the day before surgery and 75 mg i.m. every 12 h on the day of surgery, n = 23) or placebo (n = 23). Standardized combined general anaesthesia and epidural analgesia was administered. Serum IL-6, IL-10 and cortisol were measured before surgery and 30 min and 2, 6, 12 and 24 h after skin incision. Temperature, leucocyte count and C-reactive protein concentration were measured before surgery and after 24 h. IL-6 and IL-10 concentrations increased, reaching peak levels at 12 and 6 h respectively in both groups. At 12 h, the IL-6 concentration was significantly lower in patients receiving diclofenac than in those receiving placebo (P = 0.003). In contrast, IL-10 concentration at 6 h was higher in diclofenac-treated patients (P = 0.008), and this was associated with less pyrexia (P = 0.03), a lower leucocyte count (P = 0.0002) and a lower C-reactive protein concentration (P = 0.0039). Serum cortisol concentration was similar in the two groups of patients until 24 h, when the concentration was lower in patients who received diclofenac (P = 0.002). Cortisol concentration correlated with IL-6 concentration at 24 h. Administration of diclofenac was associated with lower IL-6 and higher IL-10 concentrations, and lower leucocyte count, C-reactive protein concentration and temperature. Diclofenac may have an anti-inflammatory role in major surgery.

Cytokine Responses to Physical Activity, with Particular Reference to IL-6: Sources, Actions, and Clinical Implications

The present review examines the cytokine response to acute exercise stress, with particular emphasis on the balance between proinflammatory and anti-inflammatory mechanisms, and the release of IL-6. Prolonged endurance exercise induces a sequenced release of pro- and anti-inflammatory cytokines, and IL-6 plays a dominant role. The magnitude of this response bears a general relationship to the intensity of effort, but the duration of activity and many environmental factors also modulate cytokine release. Although many types of cells are capable of producing cytokines, the main source of the exercise-induced IL-6 production appears to be the exercising muscle. The primary function of the additional IL-6 may be to regulate the supply of carbohydrate as muscle reserves of glycogen become depleted. There is also a delayed release of cytokines following eccentric exercise that is related to the repair of muscle injury. Since the production of cytokines is greater with endurance than with resistance exercise, it seems unlikely that they play an important role in the hypertrophy of muscle and bone. More research is needed on a number of important clinical issues where the exercise-induced release of cytokines may have relevance. Exercise-induced cytokine secretion has the potential to provide a simple model of sepsis. Preliminary observations suggest it may also modulate the risk of type 2 diabetes mellitus. Cytokine concentrations are increased in chronic fatigue syndrome, although it is less dear that the cytokine secretion is responsible for fatigue in humans. Exercise-induced modulations in cytokine secretion may contribute to allergies, bronchospasm, and upper respiratory infections in the endurance athlete. Further, the cytokine cascade is involved in the process of atherogenesis, and exercise-induced changes in cytokine production may expose latent HIV to chemotherapeutic agents.

Qualitative and Quantitative Assessment of the Benefit???Risk Ratio of Medium Potency Topical Corticosteroids In Vitro and In Vivo

Corticosteroids are widely used for the treatment of inflammatory skin disorders. However, systemic and local adverse drug reactions, especially skin atrophy, are potential complications that limit their use. Several attempts have been made to increase the safety of topical corticosteroid treatment, including new application schedules, special vehicles and new agents. In particular, the group of hydrocortisone and prednisolone double esters, with prednicarbate as the first and most often prescribed representative, seem to be equipotent alternatives to the gold standard betamethasone 17-valerate with respect to anti-inflammatory activity. At the same time, these new agents induce less skin atrophy, which may result from a unique skin metabolism and a specific influence on the cytokine network in the epidermis and dermis. On the basis of these effects, a new approach to in vitro quantification of the benefit-risk ratio has been developed. As already suggested by investigations in human volunteers, the benefit-risk ratio of the new compounds appears to be increased. Therefore, recent research has focused on drugs that selectively modulate cytokine release.

Treatment of H. pylori infected mice with antioxidant astaxanthin reduces gastric inflammation, bacterial load and modulates cytokine release by splenocytes

Helicobacter pylori is a Gram-negative bacterium affecting about half of the world population, causing chronic gastritis type B dominated by activated phagocytes. In some patients the disease evolves into gastric ulcer, duodenal ulcer, gastric cancer or MALT lymphoma. The pathogenesis is in part caused by the immunological response. In mouse models and in human disease, the mucosal immune response is characterized by activated phagocytes. Mucosal T-lymphocytes are producing IFN-γ thus increasing mucosal inflammation and mucosal damage. A low dietary intake of antioxidants such as carotenoids and vitamin C may be an important factor for acquisition of H. pylori by humans. Dietary antioxidants may also affect both acquisition of the infection and the bacterial load of H. pylori infected mice. Antioxidants, including carotenoids, have anti-inflammatory effects. The aim of the present study was to investigate whether dietary antoxidant induced modulation of H. pylori in mice affected the cytokines produced by H. pylori specific T-cells. We found that treatment of H. pylori infected mice with an algal cell extract containing the antioxidant astaxanthin reduces bacterial load and gastric inflammation. These changes are associated with a shift of the T-lymphocyte response from a predominant Th1-response dominated by IFN-γ to a Th1/Th2-response with IFN-γ and IL-4. To our knowledge, a switch from a Th1-response to a mixed Th1/Th2-response during an ongoing infection has not been reported previously.

Epinephrine and endotoxin tolerance differentially modulate serum cytokine levels to high-dose lipopolysaccharide challenge in a murine model

Background: The epinephrine tolerance state has been demonstrated to increase survival in endotoxic shock and was claimed to have cross-tolerance with endotoxin tolerance. With use of these data, we aimed to determine the effect of epinephrine and endotoxin tolerance on major cytokine levels in a lipopolysaccharide challenge in mice. Methods: Epinephrine tolerance was induced by beginning with a low dose and gradually increasing to a lethal dose. Endotoxin tolerance was induced by injecting saline solution for 4 days and lipopolysaccharide 1 mg/kg on the fifth day. After these procedures, saline solution or 20 mg/kg lipopolysaccharide was injected into animals. Peak serum levels of tumor necrosis factor-α (TNF-α), interleukin 1β, interleukin 6 (IL-6), interleukin 10 (IL-10), and interleukin 12 (IL-12) were assayed. Results: The lipopolysaccharide injection increased the levels of all the cytokines in the control and epinephrine-tolerant animals. TNF-α, IL-6, and IL-10 levels were lower in endotoxin-tolerant animals compared with controls. Epinephrine-tolerant animals had higher levels of TNF-α, IL-6, and IL-12 than the controls did. Conclusion: Epinephrine tolerance primes for an exaggerated release of TNF-α, IL-6, and IL-12 in response to lipopolysaccharide challenge, suggesting anti-inflammatory and immunosuppressive effects by epinephrine. The anti-inflammatory effect was not mediated through increased IL-10 release. Endotoxin tolerance selectively modulated cytokine release. (Surgery 1999;125:403-10.)

Inhibitory kappaBalpha control of nuclear factor-kappaB is dysregulated in endotoxin tolerant macrophages.

The transcription factor nuclear factor (NF)-kappaB is thought to be required for endotoxin-stimulated tumor necrosis factor (TNF) and interleukin (IL)-1 gene transcription. Nuclear translocation of NF-kappaB is regulated by the cytoplasmic inhibitory factor IkappaBalpha. Low-dose lipopolysaccharide (LPS) pretreatment modulates cytokine release by altering subsequent LPS-activated signal transduction pathways. In this study, we examined the effect of LPS pretreatment exposure on IkappaBalpha and NF-kappaB following activation with LPS. Murine macrophages (Mphi were exposed to a range of LPS concentrations +/-24 h PreRx with 10 ng/mL LPS pretreatment. Cytoplasmic IkappaBalpha (Western immunoblot) and NF-kappaB (gel-shift assay) were assayed 30 min after LPS activation. Gene transcription for TNF was measured 6 h after LPS activation using RT-PCR. In the absence of LPS pretreatment, IkappaBalpha disappeared from the cytoplasm coincident with nuclear translocation of NF-kappaB. Tolerant Mphi had markedly enhanced levels of IkappaBalpha and normal to increased levels of NF-kappaB translocation with a different electrophoretic shift. LPS activation enhanced cytokine gene transcription in a dose-dependent manner, and this was unaltered by LPS pretreatment. Endotoxin-tolerant Mphi also had increased cytoplasmic levels of the p65 subunit of NF-kappaB. LPS tolerance is associated with increases of cytoplasmic IkappaBalpha p65, as well as enhanced NF-kappaB. We conclude that control of NF-kappaB translocation by IkappaBalpha is dysregulated in endotoxin-tolerant Mphi.