Role of IL-10 in the crossregulation of prostaglandins and cytokines in monocytes

Progesterone modulates TNF receptors expression by Jurkat cells cultured with plasma from pregnant women with preeclampsia

Pregnant women with preeclampsia (PE) present a shift in the immune response to an inflammatory profile. This deviation could be due to the interaction of tumor necrosis factor (TNF) with TNFR1 and TNFR2 receptors, besides the failure in modulation of inflammation regulatory mechanisms. This study evaluated the effects of progesterone on the expression of TNFR1 and TNFR2 by Jurkat cells after stimulation with plasma from PE and normotensive (NT) pregnant women. Jurkat cells were cultured with or without progesterone in a medium containing 20% (v/v) plasma from PE or NT women. The expression of TNF receptors was evaluated by flow cytometry. The concentration of soluble forms of TNF receptors and cytokines was determined in culture supernatant and plasma by ELISA. The plasma of PE women showed significantly higher concentrations of sTNFR1 and TNF and lower concentrations of sTNFR2 compared to the NT group. TNFR1 receptor expression was increased in Jurkat cells, while TNFR2 was decreased after culture with PE plasma when compared with Jurkat cells cultured with progesterone and plasma from NT women. The concentration of sTNFR1, TNF, and IL-10 in the culture supernatant of Jurkat cells was increased after culture with PE plasma, while the sTNFR2 receptor was decreased when compared to the NT group. Results demonstrate that in preeclamptic women a systemic inflammation occurs with an increase of inflammatory molecules, and progesterone may have a modulating effect on the expression of TNF receptors, shifting Jurkat cells towards an anti-inflammatory profile with greater expression of TNFR2.

Oleic acid-related anti-inflammatory effects in force-stressed PdL fibroblasts are mediated by H3 lysine acetylation associated with altered IL10 expression

The initiation of a spatially and temporally limited inflammation is essential for tissue and bone remodelling by the periodontal ligament (PdL) located between teeth and alveolar bone. Nutritional components may cause alterations in the inflammatory response of PdL fibroblasts to mechanical stress such as those occurring during orthodontic tooth movement (OTM). Recently, we reported an attenuated pro-inflammatory response of human PdL fibroblasts (HPdLFs) to compressive forces when stimulated with oleic acid (OA), a monounsaturated fatty acid particularly prominent in the Mediterranean diet. Fatty acids could serve as alternative source of acetyl-CoA, thereby affecting epigenetic histone marks, such as histone 3 lysine acetylation (H3Kac) in a lipid metabolism-dependent manner. In this study, we aimed to investigate the extent to which OA exerts its anti-inflammatory effect in compressed HPdLFs via changes in H3Kac. Six-hour compressed HPdLFs showed increased H3Kac when cultured with OA. Inhibition of histone deacetylases resulted in a comparable IL10-increase as observed in compressed OA-cultures. In contrast, inhibition of histone acetyltransferases, particularly p300/CBP, in compressed HPdLFs exposed to OA normalized the inflammatory response to control levels. OA-dependent increased association of H3Kac to IL10 promoter regions in compressed HPdLFs further strengthened the assumption that OA exhibits its anti-inflammatory properties via modulation of this epigenetic mark. In conclusion, our study strongly suggests that nutritional components can directly affect PdL cells via changes in their epigenetic code. Since epigenetic inhibitors are already widely used clinically, they may hold promise for novel approaches for personalized orthodontic treatment that incorporates nutritional and metabolism-related changes.

Serum pro-inflammatory and anti-inflammatory cytokines and the pathogenesis of experimental autoimmune encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) as an experimental model of multiple sclerosis (MS) is characterized by demyelination, infiltration of inflammatory cells into the nervous system and dysregulation of serum inflammatory cytokines. We investigated the correlation of serum cytokines and other inflammatory markers with the EAE pathogenesis. After EAE induction, the levels of different serum cytokine/inflammatory mediators were measured. Furthermore, motor functions, myelination, and lymphocyte infiltration in EAE mice were also assessed. Our results revealed that the serum concentrations of T-helper 1 (Th1) and Th17 cytokines, interleukin (IL)-6, IL-1β, IL-1α and prostaglandin E2 in EAE mice were significantly higher than controls. The ratios of pro- to anti-inflammatory cytokines were different between the EAE and the control group. A statistically significant positive correlation was found between the IL-6/IL-10 ratio and the EAE severity, demyelination rate, and lymphocyte infiltration in EAE mice. Results indicate that the profiles of serum pro- and anti-inflammatory cytokines might be useful as biomarkers for monitoring the pathological manifestation of EAE. Furthermore, evaluating the dynamic interplay of serum cytokine levels and the correlation with pathogenic mechanisms of EAE may provide diagnostic and therapeutic insights for MS and some other inflammatory disorders.

Activated Platelets Induce an Anti-Inflammatory Response of Monocytes/Macrophages through Cross-Regulation of PGE2 and Cytokines

Platelets are well known for their role in hemostasis and are also increasingly recognized for their roles in the innate immune system during inflammation and their regulation of macrophage activation. Here, we aimed to study the influence of platelets on the production of inflammatory mediators by monocytes and macrophages. Analyzing cocultures of platelets and murine bone marrow-derived macrophages or human monocytes, we found that collagen-activated platelets release high amounts of prostaglandin E₂ (PGE₂) that leads to an increased interleukin- (IL-) 10 release and a decreased tumor necrosis factor (TNF) α secretion out of the monocytes or macrophages. Platelet PGE₂ mediated the upregulation of IL-10 in both cell types via the PGE₂ receptor EP2. Notably, PGE₂-mediated IL-10 synthesis was also mediated by EP4 in murine macrophages. Inhibition of TNFα synthesis via EP2 and EP4, but not EP1, was mediated by IL-10, since blockade of the IL-10 receptor abolished the inhibitory effect of both receptors on TNFα release. This platelet-mediated cross-regulation between PGE₂ and cytokines reveals one mechanism how monocytes and macrophages can attenuate excessive inflammatory responses induced by activated platelets in order to limit inflammatory processes.

N-Acetyl-l-cysteine exacerbates generation of IL-10 in cells stimulated with endotoxin in vitro and produces antipyresis via IL-10 dependent pathway in vivo

N-Acetyl-l-cysteine (NAC) is a well-known medication, primarily used as a mucolytic agent in pulmonary disease. Recently, we have found that NAC possesses antipyretic properties. The aim of the present study was to investigate the mechanism by which NAC attenuates fever. The concentration of interleukin (IL)-10 and prostaglandin (PG) E2 were measured using ELISA kit in the supernatants aspirated after stimulation of peripheral blood mononuclear cells (PBMCs) with lipopolysaccharide (LPS, 1μg/mL) and NAC (10mM). The body temperature of the Wistar rats was measured using biotelemetry system. To inhibit endotoxic fever, NAC (200mg/kg; i.p.) was injected into the rats one hour prior to the LPS administration (50μg/kg; i.p.). The pre-treatment of LPS-stimulated PBMCs with NAC resulted in a significant decrease in PGE2 concentration in comparison to the cells treated with LPS alone (PGE2 level was 386.1±61.9pg/mL vs. 2078.9±157.9pg/mL, respectively, p<0.001). Furthermore, in these cells we observed a significant increase in IL-10 level (142.1±2.62pg/mL in NAC+LPS stimulated cells vs. 54.4±0.6pg/mL in LPS stimulated cells, p<0.001). The injection of anti-IL-10 antibody into the rats abolished antipyretic properties of NAC. Body temperature in animals treated with anti-IL-10+NAC/LPS was 38.28±0.12°C vs. 37.73±0.06°C in IgG+NAC/LPS rats (p<0.001) and 38.31±0.20°C in NaCl/LPS-treated animals (n.s.). Based on these data, we conclude that NAC acts as an antipyretic via IL-10 stimulation. This finding provides a new insight into the immunopharmacology of NAC, and we believe that in a future it will contribute to the new and/or more accurate application of NAC in medicine.

Pro- and Anti-Inflammatory Cytokines Produced by Human Monocytes ChallengedIn VitrowithParacoccidioides brasiliensis

Monocytes and macrophages play a central role in innate and adaptive immune response against systemic fungal infections. Imbalances in suppressor or stimulatory cytokine secretion caused by these cells may influence disease development, microorganism death, and the nature of the adaptive immune response. This study analyzed the monocyte cytokine profiles of healthy individuals challenged with high and low virulent strains of P. brasiliensis and mRNA cytokine expression kinetics by reverse transcription polymerase chain reaction (RT-PCR). Peripheral blood monocytes from healthy volunteers were cultured in vitro with and without virulent (Pb18) or low virulence (Pb265) strains from P. brasiliensis viable yeast cells. Interleukin-1 beta (IL-1beta), IL-6, IL-8, IL-10, tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor-beta (TGF-beta1) were measured in culture supernatants by enzyme immunoassay (ELISA), and mRNA cytokine expression was determined by RT-PCR at 0, 4, 8, 12, 18 and 48 hr. Both P. brasiliensis strains induced monocyte production of IL-1beta, IL-6, IL-10 and TNF-alpha. Pb18 induced higher levels of IL-1beta, IL-6, and IL-10 than Pb265. IL-8 and TGF-beta1 levels were not significantly different from those cultured without stimulus. The mRNA cytokine expression was similar to supernatant cytokines measured by ELISA. In vitro monocyte challenge with virulent P. brasiliensis strain induces earlier and higher levels of pro- and anti-inflammatory cytokines than low virulence strain.

Alternate virtual populations elucidate the type I interferon signature predictive of the response to rituximab in rheumatoid arthritis

Background

Mechanistic biosimulation can be used in drug development to form testable hypotheses, develop predictions of efficacy before clinical trial results are available, and elucidate clinical response to therapy. However, there is a lack of tools to simultaneously (1) calibrate the prevalence of mechanistically distinct, large sets of virtual patients so their simulated responses statistically match phenotypic variability reported in published clinical trial outcomes, and (2) explore alternate hypotheses of those prevalence weightings to reflect underlying uncertainty in population biology. Here, we report the development of an algorithm, MAPEL (Mechanistic Axes Population Ensemble Linkage), which utilizes a mechanistically-based weighting method to match clinical trial statistics. MAPEL is the first algorithm for developing weighted virtual populations based on biosimulation results that enables the rapid development of an ensemble of alternate virtual population hypotheses, each validated by a composite goodness-of-fit criterion.

Results

Virtual patient cohort mechanistic biosimulation results were successfully calibrated with an acceptable composite goodness-of-fit to clinical populations across multiple therapeutic interventions. The resulting virtual populations were employed to investigate the mechanistic underpinnings of variations in the response to rituximab. A comparison between virtual populations with a strong or weak American College of Rheumatology (ACR) score in response to rituximab suggested that interferon β (IFNβ) was an important mechanistic contributor to the disease state, a signature that has previously been identified though the underlying mechanisms remain unclear. Sensitivity analysis elucidated key anti-inflammatory properties of IFNβ that modulated the pathophysiologic state, consistent with the observed prognostic correlation of baseline type I interferon measurements with clinical response. Specifically, the effects of IFNβ on proliferation of fibroblast-like synoviocytes and interleukin-10 synthesis in macrophages each partially counteract reductions in synovial inflammation imparted by rituximab. A multianalyte biomarker panel predictive for virtual population therapeutic responses suggested population dependencies on B cell-dependent mediators as well as additional markers implicating fibroblast-like synoviocytes.

Conclusions

The results illustrate how the MAPEL algorithm can leverage knowledge of cellular and molecular function through biosimulation to propose clear mechanistic hypotheses for differences in clinical populations. Furthermore, MAPEL facilitates the development of multianalyte biomarkers prognostic of patient responses in silico.

Stimulatory action of cyclooxygenase inhibitors on hematopoiesis: a review

The presented review summarizes experimental data obtained with a mouse model when investigating the relationship between inhibition of prostaglandin production and hematopoiesis. While prostaglandin E2 acts in a negative feedback control of myelopoiesis, inhibition of cyclooxygenases, responsible for its production, shifts the feedback to positive control. Based on these relationships, agents inhibiting cyclo-oxygenases, known as non-steroidal anti-inflammatory drugs (NSAIDs), can activate hematopoiesis and be protective or curative under myelosuppressive states. The effectiveness of therapeutic use of NSAIDs in these situations is expressive especially under the selective inhibition of cyclooxygenase-2 (COX-2), when undesirable side effects of cyclooxygenase-1 inhibition, like gastrointestinal damage, are absent. The effects of the clinically approved selective COX-2 inhibitor, meloxicam, were investigated and demonstrated significant hematopoiesis-stimulating and survival-enhancing actions of this drug in sublethally or lethally γ-irradiated mice. These effects were connected with the ability of meloxicam to increase serum levels of the granulocyte colony-stimulating factor. It can be inferred from these findings that selective COX-2 inhibitors might find their use in the treatment of myelosuppressions of various etiologies.

Carbon monoxide induces cyclooxygenase-2 expression through MAPKs and PKG in phagocytes

Many biological functions of heme oxygenase (HO) have been attributed to its enzymatic byproduct carbon monoxide (CO). CO has been demonstrated to play an important role in down-regulation of pro-inflammatory cytokines, but few studies have investigated the effects of CO on the cyclooxygenase-2 (COX-2) expression in macrophage. Here, we assessed the induction of COX-2 by CO in macrophage with or without lipopolysaccharide (LPS) stimulation. Tricarbonyldichloro ruthenium (II) dimmer (CORM-2) is a well known CO-releasing molecule, and exhibits anti-inflammatory activity in several cell types. In this study, both CORM-2 and CO gas were used to investigate the induction of COX-2 and the underlying molecular mechanisms in macrophage. Western blot and RT-PCR analysis demonstrated that CORM-2 and CO gas (500 ppm) significantly inhibited the protein and mRNA expression of iNOS in LPS-activated macrophages. In contrast, CORM-2 and CO gas up-regulated COX-2 expression and prostaglandin E₂ (PGE₂) production in the macrophage with or without LPS. CORM-2 time-dependently induced the phosphorylation of Akt and MAPKs, and the induction of COX-2 could be blocked by Akt, PKG, and MAPKs inhibitors. Indomethacin was used to decrease CORM-2-induced PGE₂ production by inhibiting COX-2 enzyme activity. Indomethacin was unable to reverse the decrease of iNOS, but it could restore the IL-1β expression and decrease the IL-10 expression in CORM-2-treated cells. The results suggest that CO induced COX-2 expression and PGE₂ production through activating the Akt, PKG, and MAPK pathways, and CO-induced PGE₂ may modulate inflammation during macrophage activation by suppressing IL-1β expression and inducing IL-10 production.

Functional plasticity of macrophages: in situ reprogramming of tumor-associated macrophages

The extent to which the functional heterogeneity of Mvarphis is dependent on the differentiation of functional sublineages remains unresolved. One alternative hypothesis proposes that Mvarphis are functionally plastic cells, which are capable of altering their functional activities progressively in response to progressively changing signaling molecules generated in their microenvironment. This "functional plasticity" hypothesis predicts that the functionally polarized Mvarphis in chronic pathologies do not represent Mvarphi sublineages but rather, are mutable phenotypes sustained by chronic signaling from the pathological environment. Solid TAMvarphis are chronically polarized to provide activities that support tumor growth and metastasis and suppress adaptive immune responses. In support of the functional plasticity hypothesis, administration of slow-release microsphere-encapsulated IL-12 successfully reprogrammed TAMvarphis in situ, reducing Mvarphi support of tumor growth and metastasis and enhancing Mvarphi proimmunogenic activities. Increased knowledge of how Mvarphi function is regulated and how polarized Mvarphis can be reprogrammed in situ will increase our ability to control Mvarphi function in a variety of pathological states, including cancer and chronic inflammatory disease.

Prostaglandin E2 regulates Th17 cell differentiation and function through cyclic AMP and EP2/EP4 receptor signaling

Prostaglandins, particularly prostaglandin E2 (PGE2), play an important role during inflammation. This is exemplified by the clinical use of cyclooxygenase 2 inhibitors, which interfere with PGE2 synthesis, as effective antiinflammatory drugs. Here, we show that PGE2 directly promotes differentiation and proinflammatory functions of human and murine IL-17–producing T helper (Th17) cells. In human purified naive T cells, PGE2 acts via prostaglandin receptor EP2- and EP4-mediated signaling and cyclic AMP pathways to up-regulate IL-23 and IL-1 receptor expression. Furthermore, PGE2 synergizes with IL-1β and IL-23 to drive retinoic acid receptor–related orphan receptor (ROR)-γt, IL-17, IL-17F, CCL20, and CCR6 expression, which is consistent with the reported Th17 phenotype. While enhancing Th17 cytokine expression mainly through EP2, PGE2 differentially regulates interferon (IFN)-γ production and inhibits production of the antiinflammatory cytokine IL-10 in Th17 cells predominantly through EP4. Furthermore, PGE2 is required for IL-17 production in the presence of antigen-presenting cells. Hence, the combination of inflammatory cytokines and noncytokine immunomodulators, such as PGE2, during differentiation and activation determines the ultimate phenotype of Th17 cells. These findings, together with the altered IL-12/IL-23 balance induced by PGE2 in dendritic cells, further highlight the crucial role of the inflammatory microenvironment in Th17 cell development and regulation.

Stimulation of alpha7 nicotinic acetylcholine receptor inhibits CD14 and the toll-like receptor 4 expression in human monocytes

The lipopolysaccharide (LPS)-receptor complex, CD14/toll-like receptor 4, is known to play a role in the immune responses during sepsis. Excessive inflammation and tumor necrosis factor (TNF)-alpha synthesis have been reported to cause morbidity and mortality in endotoxemia and sepsis. Cell-to-cell interaction through the engagement between intercellular adhesion molecule 1, B7.1, and CD40 on monocytes and their ligands on T cells has been suggested to play a role in the inflammatory response such as TNF-alpha and interleukin 10 production. Nicotine, with the stimulation of the nicotinic acetylcholine receptor alpha7 subunit (alpha7-nAChR), has now become the focus of attention because of its anti-inflammatory effects. However, little is known about the mechanism of the inhibitory effects induced by nicotine on the LPS-induced immune responses. In the present study, we found that nicotine suppressed the expression of CD14, toll-like receptor 4, intercellular adhesion molecule 1, B7.1, and CD40 on monocytes and the production of TNF-alpha, but not interleukin 10, in human peripheral blood mononuclear cells in the presence of LPS. The actions of nicotine were reversed by a nonselective and a selective alpha7-nAChR antagonist, mecamylamine and alpha-bungarotoxin, respectively. Therefore, nicotine might inhibit the LPS receptor complex expression via alpha7-nAChR, thus leading to a decrease in the adhesion molecule expression and TNF-alpha production. Moreover, we demonstrated that a nuclear factor-kappaB and a p38 mitogen-activated protein kinase inhibitor mimicked the actions of nicotine in the presence of LPS. These results suggested that the nuclear factor-kappaB and p38 mitogen-activated protein kinase might be involved in the actions of nicotine.

Stimulated recovery of perturbed haematopoiesis by inhibition of prostaglandin production — promising therapeutic strategy

Inhibitors of prostaglandin production, designated as classical non-steroidal anti-inflammatory drugs (NSAIDs) and acting on the base of non-selective inhibition of cyclooxygenases, have been found in numerous studies to potentiate recovery of perturbed haematopoiesis by removing the negative feedback control mediated by prostaglandins. However, classical NSAIDs show pronounced undesirable gastrointestinal side effects, which limits the possibility of their utilization for various pathophysiological states including myelosuppression. Specific cyclooxygenase-2 (COX-2) inhibitors, targeted at selective inhibition of this inducible cyclooxygenase isoform and having much better gastrointestinal side effect profile, have been found in recent studies to retain the haematopoiesis-stimulating effects of classical NSAIDs. These results suggest that the indication spectrum of selective COX-2 inhibitors may be extended to the indication of myelosuppression of various etiology. Combining the anti-tumour and haematopoiesis-stimulating activities in a single COX-2 inhibitor may have a positive clinical impact.

Oxidative stress and lipid mediators induced in alveolar macrophages by ultrafine particles

In ambient aerosols, ultrafine particles (UFP) and their agglomerates are considered to be major factors contributing to adverse health effects. Reactivity of agglomerated UFP of elemental carbon (EC), Printex 90, Printex G, and diesel exhaust particles (DEP) was evaluated by the capacity of particles to oxidize methionine in a cell-free in vitro system for determination of their innate oxidative potential and by alveolar macrophages (AMs) to determine production of arachidonic acid (AA), including formation of prostaglandin E2 (PGE2), leukotriene B4 (LTB4), reactive oxygen species (ROS), and oxidative stress marker 8-isoprostane. EC exhibiting high oxidative potential induced generation of AA, PGE2, LTB4, and 8-isoprostane in canine and human AMs. Printex 90, Printex G, and DEP, showing low oxidative capacity, still induced formation of AA and PGE2, but not that of LTB4 or 8-isoprostane. Aging of EC lowered oxidative potential while still inducing production of AA and PGE2 but not that of LTB4 and 8-isoprostane. Cellular ROS production was stimulated by all particles independent of oxidative potential. Particle-induced formation of AA metabolites and ROS was dependent on mitogen-activated protein kinase kinase 1 activation of cytosolic phospholipase A2 (cPLA2) as shown by inhibitor studies. In conclusion, cPLA2, PGE2, and ROS formation was activated by all particle types, whereas LTB4 production and 8-isoprostane were strongly dependent on particles' oxidative potential. Physical and chemical parameters of particle surface correlated with oxidative potential and stimulation of AM PGE2 and 8-isoprostane production.

Inhibitory effects of proanthocyanidins from Ribes nigrum leaves on carrageenin acute inflammatory reactions induced in rats

Background

The anti-inflammatory effects of proanthocyanidins (PACs), isolated from blackcurrant (Ribes nigrum L.) leaves, were analysed using carrageenin-induced paw oedema and carrageenin-induced pleurisy in rats.

Results

Pretreatment of the animals with PACs (10, 30, 60 and 100 mg/kg, i.p.) reduced paw oedema induced by carrageenin in a dose and time-dependent manner. PACs also inhibited dose-dependently carrageenin-induced pleurisy in rats. They reduced (A) lung injury, (B) pleural exudate formation, (C) polymorphonuclear cell infiltration, (D) pleural exudate levels of TNF-α, IL-1β and CINC-1 but did not affect IL-6 and IL-10 levels. They reduced (E) pleural exudate levels of nitrite/nitrate (NOx). In indomethacin treated rats, the volume of pleural exudate was low, its content in leukocytes and its contents in TNF-α, IL-1β, IL-6 and IL-10 but not in NOx were reduced. These data suggest that the anti-inflammatory properties of PACs are achieved through a different pattern from those of indomethacin.

Conclusion

These results suggest that the main mechanism of the anti-inflammatory effect of PACs mainly lies in an interference with the migration of the leukocytes. Moreover, PACs inhibited in vivo nitric oxide release.

Inhibition of IL-6, TNF-alpha, and cyclooxygenase-2 protein expression by prostaglandin E2-induced IL-10 in bone marrow-derived dendritic cells

Several endogenously produced mediators, including cytokines such as IL-6, IL-10, and TNF-alpha and prostanoids such as prostaglandin E(2) (PGE(2)), regulate dendritic cell (DC) function and contribute to immune homeostasis. In this study, we report that exogenous PGE(2) enhances the production of IL-10 from bone marrow-derived DC (BM-DC). IL-6, but not TNF-alpha, release is enhanced by PGE(2) in the presence of anti-IL-10, suggesting that endogenous IL-10 masks PGE(2)-induced IL-6. Furthermore, both exogenous IL-10 and PGE(2) inhibit LPS-induced IL-6 and TNF-alpha, whereas selective inhibition of cyclooxygenase-2 (COX-2) or addition of anti-IL-10 causes the reverse effects. Exogenous IL-10, but not IL-6, dose-dependently suppresses COX-2 protein expression and PGE(2) production, and TNF-alpha does not reverse this effect. In contrast, anti-IL-10 up-regulates prostanoid production by LPS-stimulated BM-DC. Taken together, our results show that in response to PGE(2), BM-DC produce IL-10, which in turn down-regulates their own production of IL-6-, TNF-alpha-, and COX-2-derived prostanoids, and plays crucial roles in determining the BM-DC pro-inflammatory phenotype.

Effects of isoflurane-induced and prostaglandin E(1)-induced hypotension on cytokine responses to oral and maxillofacial surgery

STUDY OBJECTIVE

To evaluate the effect of induced hypotension with isoflurane or prostaglandin E(1) (PGE(1)) on cytokine responses to surgery.

DESIGN

Prospective, randomized study.

SETTING

University hospital.

PATIENTS

24 ASA physical status I and II patients undergoing elective oral and maxillofacial surgery.

INTERVENTIONS

Patients were randomly allocated to three groups be anesthetized in the normotension (Control group), isoflurane-induced hypotension (Isoflurane-H group), and PGE(1)-induced hypotension (PGE(1)-H group). Mean arterial pressure during hypotension was maintained at approximately 80% of baseline values.

MEASUREMENTS AND MAIN RESULTS

Blood samples were taken before induction of anesthesia and during and after hypotension. Plasma tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-10 (IL-10) levels were measured using enzyme-linked immunosorbent assay. There were no differences in TNF-alpha or IL-10 levels among the groups. However, the elevation of the plasma IL-6 level in the PGE(1)-H group was found during hypotension, compared with the control group (p < 0.05).

CONCLUSIONS

PGE(1)-induced hypotension has an effect on IL-6 response to oral and maxillofacial surgery.

Receptors, mediators, and mechanisms involved in bacterial sepsis and septic shock

Bacterial sepsis and septic shock result from the overproduction of inflammatory mediators as a consequence of the interaction of the immune system with bacteria and bacterial wall constituents in the body. Bacterial cell wall constituents such as lipopolysaccharide, peptidoglycans, and lipoteichoic acid are particularly responsible for the deleterious effects of bacteria. These constituents interact in the body with a large number of proteins and receptors, and this interaction determines the eventual inflammatory effect of the compounds. Within the circulation bacterial constituents interact with proteins such as plasma lipoproteins and lipopolysaccharide binding protein. The interaction of the bacterial constituents with receptors on the surface of mononuclear cells is mainly responsible for the induction of proinflammatory mediators by the bacterial constituents. The role of individual receptors such as the toll-like receptors and CD14 in the induction of proinflammatory cytokines and adhesion molecules is discussed in detail. In addition, the roles of a number of other receptors that bind bacterial compounds such as scavenger receptors and their modulating role in inflammation are described. Finally, the therapies for the treatment of bacterial sepsis and septic shock are discussed in relation to the action of the aforementioned receptors and proteins.

The modulatory effects of prostaglandin-E on cytokine production by human peripheral blood mononuclear cells are independent of the prostaglandin subtype

The production of inflammatory mediators, relevant to (auto)immune diseases and chronic inflammatory conditions, can be modulated by dietary intake of n-3 and n-6 long chain polyunsaturated fatty acids (PUFAs). It was suggested that these effects are related to the formation of different series of eicosanoids, in particular prostaglandin-E (PGE). In this study we investigated whether prostaglandin subtypes metabolized from arachidonic acid (PGE2), dihomo-gamma-linolenic acid (PGE1) or eicosapentaenoic acid (PGE3) have different effects on T-cell proliferation and cytokine production in vitro. Freshly isolated human peripheral blood mononuclear cells (PBMC) were stimulated with concanavalin A (ConA) or lipopolysaccharide (LPS) in the presence or absence of exogenous PGE1, PGE2 or PGE3. We found that tumour necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) and to a lesser extent interleukin (IL)-10 production was inhibited by all PGE-subtypes in ConA-stimulated PBMC concomitant with unaffected IL-2 levels. The modulated cytokine production of ConA stimulated cells was independent of T-cell proliferation. PGE2 and PGE1 moderately stimulated proliferation, while PGE3 inhibited the proliferative response to some extent. In LPS-stimulated PBMC, TNF-alpha production was inhibited by all PGE-subtypes, whereas IL-6 remained unaffected and IL-10 production was increased. Time course experiments on the effects of PGE-subtypes on cytokine production after ConA or LPS stimulation showed these effects to be time dependent, but indifferent of the prostaglandin subtype added. Overall, the modulatory effects of PGE on cytokine production were irrespective of the subtype. This may implicate that the immunomodulatory effects of PUFAs, with respect to cytokine production, are not caused by a shift in the subtype of PGE.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Il-10 up-regulates macrophage expression of the S100 protein S100A8

The murine calcium binding protein S100A8 (A8) is a leukocyte chemoattractant, but high levels may be protective and scavenge hypochlorite. A8 is induced by LPS, IFN-gamma, and TNF in elicited macrophages. Th2 cytokines generally suppress proinflammatory gene expression, and IL-4 and IL-13 partially decreased A8 induction in macrophages and endothelial cells stimulated by LPS or IFN. In contrast, IL-10 synergized with LPS and IFN to increase mRNA levels > or =9-fold and secreted A8 levels approximately 4-fold. IL-10 decreased the optimal time of mRNA expression induced by LPS from 24 to 8 h. Blocking experiments indicated that endogenous IL-10 contributes to gene induction by LPS. Cooperation between IL-10 and LPS was not due to altered mRNA stability but was dependent on de novo protein synthesis. Transfection analysis with A8 luciferase constructs confirmed that synergy was due to increased transcription. The region of the promoter involved was localized to a 178-bp fragment flanking the transcription start site of the gene. This region was also responsible for the suppressive effects of IL-4 and IL-13. Forskolin, CTP-cAMP, and PGE(2) also enhanced LPS- and IFN-induced A8 mRNA, whereas indomethacin significantly reduced synergy between IL-10 and LPS. Mitogen-activated protein kinase/cyclooxygenase 2/cAMP pathways involving CCAAT-enhancing binding protein, located within the active promoter, may mediate A8 gene up-regulation in a manner mechanistically distinct to genes regulated by IL-10 via the STAT pathway. A8 exhibits pleiotropic effects, and the high levels secreted as a result of IL-10 synergy may regulate untoward inflammatory damage by virtue of its an antioxidant capacity.

Plasma levels of interleukin-6 and interleukin-10 are affected by ketorolac as an adjunct to patient-controlled morphine after abdominal hysterectomy

OBJECTIVE

Because morphine affects various immune functions, patient-controlled analgesia with morphine may further deteriorate the immune mechanisms after surgery. Therefore, the purpose of this study was to determine differences between morphine patient-controlled analgesia and a combination of morphine and ketorolac in interleukin-6 and interleukin-10 responses, and in analgesia and morphine-related side effects.

DESIGN

Prospective study.

PATIENTS

Twenty-two patients who underwent abdominal hysterectomy were classified randomly into two groups: (1) patient-controlled analgesia with morphine; and (2) patient-controlled analgesia with a combination of morphine and ketorolac. Blood samples to measure cytokines were collected at preoperatively, immediately postoperatively, and 2 hours, 4 hours, and 24 hours postoperatively.

OUTCOME MEASURES

Plasma was separated and frozen until the analysis of cytokines using enzyme-linked immunosorbent assays. Postoperative pain was assessed using a visual analog score. Sedation was checked based on a protocol developed at the Samsung Medical Center.

RESULTS

In the two groups, interleukin-6 increased immediately postoperatively, and it remained consistent for 24 hours. Interleukin-10 concentrations peaked at 2 hours postoperatively and progressively decreased. Cytokine concentrations between the two groups were significantly different for interleukin-6 24 hours postoperatively (p = 0.026) and for interleukin-10 4 hours postoperatively (p = 0.045). Total analgesic use was not different, but morphine consumption was significantly different (p = 0.037 at 4 hours postoperatively, p = 0.015 at 24 hours postoperatively). Pain scores, sedation, and side effects were unaffected by the patient-controlled analgesia regimen.

CONCLUSIONS

The authors conclude that supplementation using ketorolac plus administration of morphine modifies cytokine responses and may contribute to immune augmentations during postoperative periods.

Regulation of the IL-10 production by human T cells

Interleukin (IL)-10, an immunomodulatory cytokine predominantly produced by monocytes/macrophages and T cells, inhibits several functions of dendritic cells (DC), monocytes and T cells including their cytokine production, but it stimulates B cell immunoglobulin (Ig) production and cytotoxic T lymphocyte (CTL) generation. A precise knowledge of the mechanisms that control the IL-10 production is therefore highly important for understanding the immunoregulation. The IL-10 production was studied in cultures of freshly isolated human T cells. A rise in intracellular calcium as well as the common gamma-chain containing cytokine receptor triggering or CD28 triggering were found to be important signals for IL-10 induction. CD80, CD58, rIL-12 and rIFN-alpha all had efficacious and independent costimulatory activities on the IL-10 production, while PGE2 was inhibitory. Dependence on autocrine IL-2 signalling was shown by the effects of anti-IL-2 and anti-IL-2R monoclonal antibodies (MoAb), but the IL-10 production proceeded partly IL-2-independent when CD80 provided costimulation. Sensitivity to inhibition by CsA was not removed by CD80 or CD58 costimulation and/or by addition of rIL-12 or rIFN-alpha, pointing to the absolute requirement for calcineurin activity. These data reveal important differences in the regulatory pathways between IL-10 (a cytokine-inhibitory interleukin) and IL-2 (a cytokine-inducing interleukin), which can potentially be exploited therapeutically. The fact that CsA blocks the production of IL-10, which itself has important immunosuppressive properties, should be taken into account in defining immunosuppressive treatment schedules which include the use of CsA.

Interaction of indomethacin with cytokine production in whole blood. Potential mechanism for a brain-protective effect

Both Alzheimer's disease and vascular dementia are featured by inflammatory responses and it is known that non-steroidal anti-inflammatory drugs (NSAIDs) decrease the risk and severity of these diseases. To study the effect of NSAIDs on PGE2 levels and pro- and anti-inflammatory cytokine levels in the whole blood assay, blood samples from 23 elderly persons aged 85 years were stimulated with thrombin or LPS as primary stimulus. Indomethacin was added in concentrations ranging from 0.4 to 16 microg/ml and acetylsalicylic acid was added to in concentrations ranging from 0.5 to 8.0 microg/ml. Indomethacin abrogated thrombin- and LPS-induced PGE2 production at all concentrations tested. In addition, indomethacin reduced the production of thrombin-induced IL-6 and IL-10 (p<0.05) at physiological concentrations. Indomethacin reduced the production of LPS-induced IL-6, IL-1 beta and IL-10 (p<0.05) at the highest indomethacin concentration tested. Similar results were obtained upon incubation with acetylsalicylic acid. It is concluded that indomethacin may reduce the thrombin-induced inflammatory reaction by decreasing IL-6 through inhibition of PGE2 synthesis. This IL-6 reduction may be relevant for the ability of indomethacin to reduce the risk of Alzheimer's disease. However, the decrease in IL-10 production due to indomethacin suggests a more inflammatory state.

Captopril inhibits in vitro and in vivo the proliferation of primitive haematopoietic cells induced into cell cycle by cytotoxic drug administration or irradiation but has no effect on myeloid leukaemia cell proliferation

Angiotensin I-converting enzyme (ACE) has been shown to be involved in the catabolism of the tetrapeptide acetyl-Ser-Asp-Lys-Pro (AcSDKP). As AcSDKP is a physiological inhibitor of haematopoietic stem cell proliferation, we investigated the in vitro and in vivo effects of captopril, one of the specific inhibitors of ACE, on the proliferation of primitive haematopoietic cells. Regenerating bone marrow cells obtained from mice given one injection of cytosine arabinoside (100 mg/kg) as well as SA2 myeloid leukaemia cells were incubated in vitro for 24 h with 10-6 M captopril. Captopril significantly reduced the proportion of high proliferative potential colony-forming cells (HPP-CFC-1) in S-phase, whereas it had no effect on the proportion of SA2 leukaemic colony-forming cells in S-phase. When given in vivo to mice 1 h after 2 Gy gamma-irradiation or cytosine arabinoside (AraC) injection, captopril (100 mg/kg) was shown to prevent HPP-CFC-1 entry into S-phase induced by these cytotoxic treatments. The observed effects correlated with a reduction in ACE degradative activity and an increase in the level of endogenous AcSDKP both in the supernatants of captopril-treated bone marrow cells and in plasma of treated animals. The present findings suggest that AcSDKP might mediate the observed in vitro and in vivo inhibitory effects of captopril on primitive haematopoietic cell proliferation.

Viral IL-10 gene transfer decreases inflammation and cell adhesion molecule expression in a rat model of venous thrombosis

Post-thrombotic inflammation probably contributes to chronic venous insufficiency, and little effective treatment exists. IL-10 is an anti-inflammatory cytokine that previously has been shown to decrease perithrombotic inflammation and thrombosis. We investigated in a rat model whether local expression of viral IL-10 (vIL-10) in a segment of vein that undergoes thrombosis would confer an anti-inflammatory effect and how this effect might be mediated. Rats underwent inferior vena cava isolation, cannulation, and instillation of saline or adenovirus encoding either beta-galactosidase or vIL-10. Two days after transfection, thrombosis was induced, 2 days after this the rats underwent gadolinium (Gd)-enhanced magnetic resonance venography exam, and the vein segments were harvested. Tissue transfection was confirmed by either RT-PCR of vIL-10 or positive 5-bromo-4-chloro-3-indolyl beta-d-galactopyranoside (X-Gal) staining. vIL-10 significantly decreased both leukocyte vein wall extravasation and area of Gd enhancement compared with those in controls, suggesting decreased inflammation. Immunohistochemistry demonstrated decreased endothelial border staining of P- and E-selectin, while ELISA of vein tissue homogenates revealed significantly decreased P- and E-selectin and ICAM-1 levels in the vIL-10 group compared with those in controls. Importantly, native cellular IL-10 was not significantly different between the groups. However, neither clot weight nor coagulation indexes, including tissue factor activity, tissue factor Ag, or von Willebrand factor levels, were significantly affected by local vIL-10 expression. These data suggest that local transfection of vIL-10 decreases venous thrombosis-associated inflammation and cell adhesion molecule expression, but does not directly affect local procoagulant activity.

Selective Pharmacologic Inhibition of Murine and Human IL-12-Dependent Th1 Differentiation and IL-12 Signaling

We have previously shown that lisofylline (LSF) inhibits murine Th1-mediated disease in vivo by blocking IL-12-induced differentiation of Th1 cells. The cellular and molecular mechanisms underlying this inhibition were further explored by testing LSF in several IL-12-responsive model systems in vitro. IL-12-dependent Th1 differentiation was abrogated by LSF and yielded effector T cells that were deficient in proinflammatory cytokine secretion, including IFN-γ, IL-2, and TNF-α. The diminished Th1 phenotype resulted from both a lower frequency of IL-12-derived Th1 clones and a reduced capacity of individual clones to secrete IFN-γ due to lower levels of IFN-γ mRNA. The arrest in Th1 development resulted from a blockade of IL-12 signaling that preceded the Th0 to Th1 transition. Thus, LSF blocked IL-12-enhanced IFN-γ production in anti-CD3-stimulated T cells and prevented IL-12-mediated repression of the transcription factor GATA-3. Lisofylline also inhibited IL-12-induced increases in STAT4 tyrosine phosphorylation, but did not block TCR signaling or inhibit acquisition of IL-12 responsiveness. These findings were extended to show that LSF also inhibits IL-12-dependent responses in human T cells. LSF, which has one asymmetric chiral center, was selectively inhibitory for IL-12 signaling compared with its S-enantiomer (1501-S) and the oxidized side chain analog, pentoxifylline. The results suggest that LSF may be useful as a modulator of Th1-mediated disease in humans.