Systemic up-regulation of sTNFR2 and IL-6 in Porphyromonas gingivalis pneumonia in mice

Aspiration pneumonia is a common cause of death in older people, and the pathophysiology is a chronic respiratory failure with a mild airway inflammation. In this study, we established a mild inflammatory pneumonia model using Porphyromonas gingivalis (Pg) pathogen-infected mice. It elucidated the effects of Pg-infected pneumonia on proinflammatory cytokines tumor necrosis factor (TNF)-alpha, interleukin-6 (IL-6), and IL-1beta production in both lung tissue and serum. We also elucidated production of soluble (s) TNF receptor (R) s, because TNF-alpha is considered to be a dominant inflammatory mediator. Lung TNF-alpha levels significantly increased at 2 h after infection, and rapidly returned to basal level at 24 h. Consistent with increase of TNF-alpha, remarkable increase of sTNFR2 but not sTNFR1 was detected in lung tissue from 2 to 72 h. Interestingly, sTNFR2/sTNFR1 ratio was significantly enhanced at 2 h in serum. In addition, lung IL-1beta and IL-6 levels also significantly increased from 2 to 24 h. Importantly, we found that IL-6 levels in serum reflected its local level. These results may suggest that systemically produced sTNFR2 and IL-6 could be a key role to modulate proinflammatory activities of TNF-alpha in Pg-induced lung inflammation simulated aspiration pneumonia.     

GRACE score of myocardial infarction patients correlates with oxidative stress index,hsCRP and inflammation

BackgroundEtiopathogenesis of myocardial infarction (MI) is contributed by oxidative injury and inflammatory response. The interplay of these processes determines outcomes in MI patients. However, studies showing the relationship of oxidative stress and inflammatory cytokines with prognosis and severity of MI are lacking.ObjectiveThe present study was designed to assess the degree of oxidative stress and inflammation in correlation with GRACE (Global Registry of Acute Coronary Events) risk score in patients of MI.MethodsMI patients were segregated according to GRACE risk score and age. Blood samples of the patients were used for determination of level of total peroxide, Total Antioxidant Status (TAS), Oxidative Stress Index (OSI), pro-inflammatory molecules such as high sensitive C-reactive protein (hsCRP), Tumor Necrosis Factor α (TNFα), interleukin 1 β (IL 1β), interleukin 6 (IL 6), anti-inflammatory cytokine interleukin 10 (IL 10), and TNFα/IL 10 cytokine ratio.ResultsWe found significant elevation in concentration of total peroxide, TAS and OSI in all MI patients than healthy volunteers, this elevation showed pronouncement with higher GRACE score (GS) and age. Alteration in pro-inflammatory and anti-inflammatory cytokines was seen in MI patients than control group, and this alteration displayed polarization with GS and age.ConclusionMI patients with higher GS and age have greater degree of OSI and inflammation, and these biochemical parameters were significantly correlated with GS and thus disease severity.     

TNF and MAP kinase signalling pathways

The binding of tumour necrosis factor α (TNFα) to cell surface receptors engages multiple signal transduction pathways, including three groups of mitogen-activated protein (MAP) kinases: extracellular-signal-regulated kinases (ERKs); the cJun NH₂-terminal kinases (JNKs); and the p38 MAP kinases. These MAP kinase signalling pathways induce a secondary response by increasing the expression of several inflammatory cytokines (including TNFα) that contribute to the biological activity of TNFα. MAP kinases therefore function both upstream and down-stream of signalling by TNFα receptors. Here we review mechanisms that mediate these actions of MAP kinases during the response to TNFα.     

The role of IL‐28, IFN‐γ, and TNF‐α in predicting response to pegylated interferon/ribavirin in chronic HCV patients

The primary goal of HCV therapy is to achieve a sustained virological response (SVR). Many host and viral factors influence the treatment response. Cytokines play an important role in the defense against viral infections, where successful treatment of hepatitis C depends on a complex balance between pro‐ and anti‐inflammatory responses. In the present study, we investigated the relationship between the presence and percentage of some cytokines (IL‐28, IFN‐γ, and TNF‐α) regarding different clinicopathological parameters including response to therapy in chronic HCV patients using immunohistochemical technique. This study was carried out on 64 chronic HCV patients (34 responders and 30 non‐responders). Of cases, 54% showed IL‐28 expression, which was associated with low AST (p = 0.002) and low HAI score (p = 0.006). Of cases, 67 and 45% showed IFN‐γ and TNF‐α expression, respectively, where the median percentage of TNF‐α expression was higher in grade II spotty necrosis compared to grade I. Some inflammatory cytokines expressed by intrahepatic inflammatory cells in chronic HCV patients promote inflammation and injury (pro‐inflammatory) such as TNF‐α. Other cytokines aid in resolving inflammation and injury (anti‐inflammatory) such as IL‐28. The balance between these cytokines will determine the degree of inflammatory state. None of the investigated cytokines proved its clear cut role in affecting response to therapy, however, their levels varied between responders and non‐responders for further investigations to clarify.     

Interleukin 17 inhibits progenitor cells in rheumatoid arthritis cartilage

Mesenchymal stem cells are known to exert immunomodulatory effects in inflammatory diseases. Immuneregulatory cells lead to progressive joint destruction in rheumatoid arthritis (RA). Proinflammatory cytokines, such as tumour necrosis factor α (TNF‐α) and interleukins (ILs) are the main players. Here, we studied progenitor cells from RA cartilage (RA‐CPCs) that are positive for IL‐17 receptors to determinate the effects of inflammation on their chondrogenic potenial. IL‐17A/F reduced the chondrogenic potential of these cells via the upregulation of RUNX2 protein and enhanced IL‐6 protein and MMP3 mRNA levels. Blocking antibodies against IL‐17 positively influenced their repair potential. Furthermore, treating the RA‐CPCs with the anti‐human IL‐17 antibody secukinumab or the anti‐TNF‐α antibody adalimumab reduced the proinflammatory IL‐6 protein level and positively influenced the secretion of anti‐inflammatory IL‐10 protein. Additionally, adalimumab and secukinumab in particular reduced RUNX2 protein to promote chondrogenesis. The amelioration of inflammation, particularly via IL‐17 antagonism, might be a new therapeutic approach for enhancing intrinsic cartilage repair mechanisms in RA patients.     

Contribution of tumor necrosis factor α and interleukin-1 α on the production of macrophage inflammatory protein-2 in response to respiratory syncytial virus infection in a murine macrophage cell line,RAW264.7

The production of several inflammatory cytokines, such as murine macrophage inflammatory protein-2 (MIP-2), tumor necrosis factor (TNF), and interleukin (IL)-1, was investigated in response to respiratory syncytial virus (RSV) infection in a murine macrophage cell line, RAW264.7, with special reference to mutual relation of their productions. The kinetics of MIP-2 production showed a trend for a biphasic pattern, that is, MIP-2 levels became detectable from 2 h postinfection (p.i.) and increased markedly until 8 h p.i. Thereafter, this level fell to the same level until 16 h p.i. and then increased again. TNF α was also detectable at 2 h p.i. and then increased sharply until 8 h p.i., when the peak level attained. Compared with the levels of MIP-2 and TNF α, that of IL-1 α/β, especially IL-1 β, was lower (ng versus pg/ml order). The presence of anti-TNF α or anti-IL-1 α antibody did not influence the early phase of MIP-2 production but significantly inhibited the late phase, suggesting that MIP-2 is induced by the combined effects of RSV infection via direct induction and indirectly after initial induction of TNF α and IL-1 α productions. Although RSV-infected RAW264.7 cells had no alteration inviability compared with mock-infected control, these data demonstrate that RSV is a potent inducer of inflammatory cytokines by direct induction and indirectly via the initial production of other cytokines. J. Med. Virol. 53:145–149, 1997. © 1997 Wiley-Liss, Inc.     

Adipose Tissue Immune Response: Novel Triggers and Consequences for Chronic Inflammatory Conditions

Adipose tissue inflammation mediates the association between excessive body fat accumulation and several chronic inflammatory diseases. A high prevalence of obesity-associated adipose tissue inflammation was observed not only in patients with cardiovascular conditions but also in patients with inflammatory bowel diseases, abdominal aortic aneurysm, or cardiorenal syndrome. In addition to excessive caloric intake, other triggers promote visceral adipose tissue inflammation followed by chronic, low-grade systemic inflammation. The infiltration and accumulation of immune cells in the inflamed and hypertrophied adipose tissue promote the production of inflammatory cytokines, contributing to target organ damages. This comorbidity seems to delimit subgroups of individuals with systemic adipose tissue inflammation and more severe chronic inflammatory diseases that are refractory to conventional treatment. This review highlights the association between adipose tissue immune response and the pathophysiology of visceral adiposity-related chronic inflammatory diseases, while suggesting several new therapeutic strategies.     

The inflammatory consequences of psychologic stress: relationship to insulin resistance, obesity, atherosclerosis and diabetes mellitus, type II

Inflammation is frequently present in the visceral fat and vasculature in certain patients with cardiovascular disease (CVD) and/or adult onset Diabetes Mellitus Type II (NIDDM). An hypothesis is presented which argues that repeated acute or chronic psychologically stressful states may cause this inflammatory process. The mediators are the major stress hormones norepinephrine (NE) and epinephrine (E) and cortisol together with components of the renin-angiotensin system (RAS), the proinflammatory cytokines (PIC), as well as free fatty acids (ffa), the latter as a result of lipolysis of neutral fat. NE/E commence this process by activation of NF(kappa)B in macrophages, visceral fat, and endothelial cells which induces the production of toll-like receptors which, when engaged, produce a cascade of inflammatory reactions comprising the acute phase response (APR) of the innate immune system (IIS). The inflammatory process is most marked in the visceral fat depot as well as the vasculature, and is involved in the metabolic events which culminate in the insulin resistance/metabolic syndromes (IRS/MS), the components of which precede and comprise the major risk factors for CVD and NIDDM. The visceral fat has both the proclivity and capacity to undergo inflammation. It contains a rich blood and nerve supply as well as proinflammatory molecules such as interleukin 6 (IL-6), tumor necrosis factor alpha (TNFalpha), leptin, and resistin, the adipocytokines, and acute phase proteins (APP) which are activated from adipocytes and/or macrophages by sympathetic signaling. The inflammation is linked to fat accumulation. Cortisol, IL-6, angiotensin II (angio II), the enzyme 11(beta) hydroxysteroid dehydrogenase-1 and positive energy balance, the latter due to increased appetite induced by the major stress hormones, are factors which promote fat accumulation and are linked to obesity. There is also the capacity of the host to limit fat expansion. Sympathetic signaling induces TNF which stimulates the production of IL-6 and leptin from adipocytes; these molecules promote lipolysis and ffa fluxes from adipocytes. Moreover, catecholamines and certain PIC inhibit lipoprotein lipase, a fat synthesizing enzyme. The brain also participates in the regulation of fat cell mass; it is informed of fat depot mass by molecules such as leptin and ffa. Leptin stimulates corticotrophin releasing hormone in the brain which stimulates the SNS and HPA axes, i.e. the stress response. Also, ffa through portal signaling from the liver evoke a similar stress response which, like the response to psychologic stress, evokes an innate immune response (IIR), tending to limit fat expansion, which culminates in inflammatory cascades, the IRS-MS, obesity and disease if prolonged. Thus, the brain also has the capacity to limit fat expansion. A competition apparently exists between fat expansion and fat loss. In "western" cultures, with excessive food ingestion, obesity frequently results. The linkage of inflammation to fat metabolism is apparent since weight loss diminishes the concentration of inflammatory mediators. The linkage of stress to inflammation is all the more apparent since the efferent pathways from the brain in response to fat signals, which results in inflammation to decrease and limit fat cell mass, is the same as the response to psychologic stress, which strengthens the hypothesis presented herein.     

Regulation of Human Decidual Cell Macrophage Inflammatory Protein-1α (MIP-1α) Production by Inflammatory Cytokines

PROBLEM : Inflammation of human gestational tissues is a key pathophysiologic event in the genesis of infection-associated preterm labor. Human gestational tissues produce several inflammatory cytokines after stimulation with bacterial products. These include interleukin-1β (IL-1β), tumor necrosis factor-α (TNFα), and IL-6. Another class of cytokines includes chemokines of the “C-C” subclassification such as macrophage inflammatory protein-1α (MlP-1α). The purpose of this study was to determine whether cultured human decidual cells produce MIP-1α in response to other inflammatory cytokines. METHODS : Various concentrations of IL-1β, TNFα, IL-6, and IL-4 were incubated with confluent monolayer cultures of decidual cells isolated from normal term placentae for 16 h at 37°C, and MlP-1α concentrations in culture supernatants were measured by ELISA. RESULTS : We found that incubation of decidual cells with IL-1β, TNFα, and IL-4 resulted in significant concentration-dependent increases in M1P-1α production. IL-6 had no effect on MlP-1α production. CONCLUSIONS : Our data are the first to show that human decidual cells in culture produce MlP-1α in response to other inflammatory cytokines. We suggest that decidual cell production of MIP-1α is an important early event in the pathophysiology of infection-associated preterm labor.     

α2,3-Sialyl and α1,3-fucosyltransferase-dependent synthesis of sialyl Lewis x,an essential oligosaccharide present on L-selectin counterreceptors,in cultured endothelial cells

Sialyl Lewis x (sLex) oligosaccharides have been shown to be present in counterreceptors for L-selectin. We and others have previously shown that high endothelial cells in lymph nodes and at sites of inflammation express sLex. Here we show that also cultured human umbilical vein endothelial cells (HUVEC) express sLex on their cell surface. This oligosaccharide is formed by sequential action of α2,3-sialyl- (α2,3-ST) and α1,3-fucosyltransferases (α1,3-FT) on N-acetyllactosamine. At least two of the several α2,3-ST and four of the several α1,3-FT are present in HUVEC. In functional assays both α2,3-ST and α1,3-FT activities were observed in HUVEC lysates with exogenous lactosamine and sialyllactosamine acceptors, leading to the generation of the sialyllactosamine and sLex sequences, respectively. TNF stimulation increased the level of mRNA expression of FT VI, and the α1,3-FT activity in HUVEC. Taken together these data show that endothelial cells express sLex and that they possess mRNA as well as enzyme activities of several α2,3-ST and α1,3-FT necessary in the final steps of sLex synthesis. Furthermore, inflammatory cytokines such as TNF can enhance transferase activities relevant in generating putative L-selectin counterreceptors.     

Saturated fatty acids activate the inflammatory signalling pathway in Schwann cells: Implication in sciatic nerve injury

Sciatic nerve injury affects quality of life. Many immune cells and inflammatory cytokines have been reported to be involved in sciatic nerve injury, but little is known about the ligands and receptors that trigger inflammatory responses. By using a modified sciatic nerve clamp injury method, we found that the recruitment of Schwann cells and the inflammatory response were enhanced after sciatic nerve injury. Toll-like receptor 4 (TLR4), one of the major members of the TLR family, is highly expressed in Schwann cells. Under certain conditions, myeloid differentiation protein 2 (MD2) binds to TLR4 on the membrane and plays important roles in the inflammatory response. The reductions in the recruitment of Schwann cells and the inflammatory response induced by the blockade of TLR4 or MD2 suggest that TLR4 and MD2 are involved in sciatic nerve injury. What are the endogenous signals that activate the inflammatory response? A large number of free saturated fatty acids (SFAs) are released from Schwann cells, adipocytes and the blood after sciatic nerve injury. Liang et al reported that Schwann cells can be stimulated by palmitic acid (PA). Here, we found that the expression and secretion of TNF-α and IL-6 were enhanced by PA treatment. Moreover, PA activated TLR4 signalling pathway-related proteins and stimulated a strong association between TLR4 and MD2. Blocking TLR4 or MD2 reversed the PA-induced inflammatory response and TLR4 downstream signalling pathway. Thus, we speculated that SFAs act as endogenous ligands that activate TLR4/MD2, thus triggering Schwann cell inflammation during sciatic nerve injury.     

Relationship between sleep-disordered breathing and markers of systemic inflammation in women from the general population

Sleep‐disordered breathing (SDB) is a risk factor for cardiovascular disease (CVD). The underlying pathogenesis is not clear. In patients with obstructive sleep apnoea syndrome (OSAS) elevated levels of inflammatory markers, such as C‐reactive protein (CRP), interleukin‐6 (IL‐6) and tumour necrosis factor α (TNFα) have been found. These markers have also been shown as independent markers of CVD in other populations. The aim of the study was to investigate the association between SDB and systemic inflammation in a population‐based cohort of women. From 6817 women who previously answered a questionnaire concerning snoring habits, 230 habitually snoring women and 170 women regardless of snoring status went through polysomnography, anthropometric measurements and blood sampling. Analyses were made for CRP, TNFα, IL‐6, myeloperoxidase (MPO) and lysozyme. The levels of CRP, IL‐6 and lysozyme were significantly higher in subjects with apnoea–hypopnoea index (AHI) ≥15 compared with women with lower AHI. All inflammatory markers except MPO correlated to AHI and oxygen desaturation measures, and to waist circumference. In multiple linear regressions adjusting for age, waist circumference and smoking, independent correlations between oxygen desaturation indices (ODI) and inflammation were found for IL‐6 (P = 0.03 for % sleep time with saturation <90%) and TNFα (P = 0.03 for ODI 3%). No significant correlations were found between AHI and inflammation. Also, for women from the general population there is an independent correlation between SDB and inflammation, even after adjusting for obesity. The results indicate that intermittent hypoxia, and not the AHI, is related to systemic inflammation seen in OSAS.     

The damage‐associated molecular pattern HMGB1 is elevated in human alcoholic hepatitis,but does not seem to be a primary driver of inflammation

The role of sterile inflammation caused by release of damage‐associated molecular patterns (DAMP) remains unclear in human alcoholic hepatitis (AH). The DAMP, high mobility group box‐1 protein (HMGB1) is released by tissue damage and inflammation. We aimed to investigate whether HMGB1 is a primary inflammatory driver in AH by determining HMGB1 serum levels and effects on inflammatory cells from AH patients. We measured serum HMGB1 in 34 AH patients and 10 healthy controls using ELISA. Toll‐like receptor 4 (TLR4) and CD14 expressions were assessed by flow cytometry on HMGB1‐stimulated peripheral blood mononuclear cells (PBMC) and ELISA was used to measure TNF‐α and IL‐1β in the supernatants. We observed 5‐fold higher serum levels of HMGB1 in AH patients at the day of diagnosis and day 30, but no associations to clinical outcome. HMGB1 stimulation increased the expression of TLR4 on CD14+‐monocytes compared with unstimulated cells in the AH patients. The TNF‐α and IL‐1β production in response to HMGB1 was diminished in AH patients. In conclusion, AH patients have increased levels of HMGB1 in their blood. This combined with an increased TLR4 expression, but an unaffected cytokine response to HMGB1 suggest that HMGB1 is not the primary driver of inflammation in AH.     

Blocking lymphotoxin-beta receptor activation diminishes inflammation via reduced mucosal addressin cell adhesion molecule-1 (MAdCAM-1) expression and leucocyte margination in chronic DSS-induced colitis

The lymphotoxin-beta receptor (LTbetaR) pathway is critical for maintenance of organized lymphoid structures and is involved in the development of colitis. To investigate the mechanisms by which LTbetaR activation contributes to the pathology of chronic inflammation we used a soluble LTbetaR-Ig fusion protein as a competitive inhibitor of LTbetaR activation in the mouse model of chronic colitis induced by oral administration of dextran sulphate sodium. Strong expression of LTbeta which constitutes part of the LTalpha(1)beta(2) ligand complex was detected in colonic tissue of mice with chronic colitis. Treatment with LTbetaR-Ig significantly attenuated the development and histological manifestations of the chronic inflammation and reduced the production of inflammatory cytokines such as TNF, IL-1beta, and IL-6. Moreover, LTbetaR-Ig treatment significantly down-regulated mucosal addressin cell adhesion molecule-1 (MAdCAM-1) expression, leading to reduced leucocyte rolling and sticking in postcapillary and collecting venules and reduced extravasation into the intestinal mucosa as quantified by in vivo fluorescence microscopy. Thus, LTbetaR pathway inhibition ameliorates DSS-induced experimental chronic colitis in mice by MAdCAM-1 down-regulation entailing reduced lymphocyte margination and extravasation into the inflamed mucosa. Therefore, a combined treatment with reagents blocking T cell-mediated perpetuation of chronic inflammation such as LTbetaR-Ig together with direct anti-inflammatory reagents such as TNF inhibitors could constitute a promising treatment strategy for chronic colitis.     

细胞因子诱导支气管上皮细胞表达嗜酸粒细胞趋化因子

Eotaxin和新近发现的Eotaxin-2在支气管上皮细胞中的表达以及Th2型细胞因子的调节作用。以支气管上皮细胞株BEAS-2B细胞为研究对象,通过RT-PCR的方法测定Th2型细胞因子IL-4、IL-13以及促炎症因子TNF-α单独和协同刺激下BEAS-2B细胞Eotaxin和Eotaxin-2的基因表达,通过ELISA方法测定细胞培养上清液中Eotaxin蛋白的表达。EotaxinmRNA在TNF-α刺激12h后表达最高,Th2型细胞因子IL-4和IL-13与TNF-α协同刺激后表达进一步增强,Eotaxin蛋白的表达在协同刺激下也呈剂量和时间依赖性增高(P<0.01)。Eotaxin-2mRNA在TNF-α的刺激下于8h表达最高,IL-4或IL-13与TNF-α的协同刺激也使表达进一步增强,Eotaxin和Eotaxin-2两者基因表达具有相关性(P<0.05)。Th2型细胞因子可与促炎症因子TNF-α协同刺激支气管上皮细胞增强表达嗜酸粒细胞趋化因子Eotaxin和Eotaxin-2,从而吸引嗜酸粒细胞浸润至气道参与哮喘炎症过程。     

Animal models of mucosal inflammation and their relation to human inflammatory bowel disease

Animal models of inflammatory bowel disease (IBD) have been useful in the identification of those immune responses uniquely involved in IBD pathogenesis and in defining the important roles of environmental influences, such as normal luminal bacterial flora and the genetic composition of the host, in modifying IBD-associated inflammation. Recent studies have focused particular attention on CD4+ T cells which produce excessive quantities either of Th1 cytokines (IFN-gamma and TNF) directed by IL-12 or of a Th2 cytokine (IL-4), relative to the production of suppressive cytokines such as IL-10 and transforming growth factor beta. Such insights will be extremely beneficial in the development of novel approaches to the control of IBD-type inflammation, such as the use of anticytokine therapies and gene therapy, and finally, in the identification of the genetic abnormalities and the antigens driving the inflammation that underlies the human disease.     

Ozone-induced lung injury and sterile inflammation. Role of toll-like receptor 4

Inhalation of toxic doses of ozone is associated with a sterile inflammatory response characterized by an accumulation of macrophages in the lower lung which are activated to release cytotoxic/proinflammatory mediators that contribute to tissue injury. Toll-like receptor 4 (TLR4) is a pattern recognition receptor present on macrophages that has been implicated in sterile inflammatory responses. In the present studies we used TLR4 mutant C3H/HeJ mice to analyze the role of TLR4 in ozone-induced lung injury, oxidative stress and inflammation. Acute exposure of control C3H/HeOuJ mice to ozone (0.8ppm for 3h) resulted in increases in bronchoalveolar lavage (BAL) lipocalin 24p3 and 4-hydroxynonenal modified protein, markers of oxidative stress and lipid peroxidation. This was correlated with increases in BAL protein, as well as numbers of alveolar macrophages. Levels of surfactant protein-D, a pulmonary collectin known to regulate macrophage inflammatory responses, also increased in BAL following ozone inhalation. Ozone inhalation was associated with classical macrophage activation, as measured by increased NF-κB binding activity and expression of TNFα mRNA. The observation that these responses to ozone were not evident in TLR4 mutant C3H/HeJ mice demonstrates that functional TLR4 contributes to ozone-induced sterile inflammation and macrophage activation.