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OBJECTIVES We sought to investigate whether activin A could be involved in the immunopathogenesis of acute coronary syndromes. BACKGROUND Inflammatory mechanisms seem to play a pathogenic role in atherosclerosis and acute coronary syndromes, but the actual mediators have not been fully identified. Activin A, a pleiotropic member of the transforming growth factor-beta cytokine family, has recently been suggested to play a role in inflammation. METHODS We examined the role of activin A and its endogenous inhibitor follistatin in patients with stable (n = 26) and unstable angina (n = 20) and healthy control subjects (n = 20) by different experimental approaches. RESULTS 1) Patients with stable angina had raised activin A concentrations, as assessed by protein levels in serum and messenger ribonucleic acid levels in peripheral blood mononuclear cells (PBMCs). 2) Although several activin A-related mediators were upregulated in PBMCs from patients with stable angina compared with controls (i.e., activin A and Smad3), no changes or even downregulation (i.e., Smad2) were seen in unstable disease. 3) The activin type II receptors, representing the primary ligand-binding proteins, were downregulated in unstable compared with stable angina. 4) Percutaneous coronary intervention induced a decrease in the activin A/follistatin ratio, suggesting downregulatory effects on activin A activity. 5) Although activin A dose-dependently suppressed the release of inflammatory cytokines from PBMCs in angina patients, an opposite effect was found in healthy controls. CONCLUSIONS Our findings suggest an anti-inflammatory potential of activin A in angina patients, and such effects may be of particular relevance in unstable angina in which several of the activin parameters were downregulated.

Background— Inflammation is important in atherogenesis. Interleukin (IL)-1 is the prototypic inflammatory cytokine. We hypothesized a dysbalance between inflammatory and anti-inflammatory mediators in the IL-1 family in coronary artery disease (CAD) and a possible modulation of these mediators by HMG-CoA inhibitors (statins). Methods and Results— In a microarray screening experiment examining peripheral blood mononuclear cells (PBMCs) from 6 CAD patients and 4 healthy control subjects, IL-1β was identified as 1 of 25 genes whose expression were upregulated in CAD and downregulated by statins. In the following, we studied the role of IL-1β and related mediators in CAD. Our major findings were as follows. (1) Although mRNA levels of IL-1α and IL-1β were markedly reduced in PBMCs from CAD patients after 6 months of simvastatin (20 mg/d, n=15) and atorvastatin (80 mg/d, n=15) therapy, the reduction in IL-1 receptor antagonist (IL-1Ra) was more modest. Statins also reduced the spontaneous release of IL-1β and IL-1Ra from PBMCs in CAD patients. (2) mRNA levels of IL-1α, IL-1β, and IL-1Ra were increased in PBMCs from patients with stable (n=20) and unstable (n=20) angina compared with healthy control subjects (n=15). Although the unstable patients had particularly high levels of IL-1β and IL-1α, IL-1Ra was not correspondingly increased. (3) IL-1β induced release of proatherogenic cytokines from PBMCs, whereas atorvastatin partly abolished this effect. Conclusions— Our findings suggest that cytokines in the IL-1 family may represent therapeutic targets in CAD. The ability of statins to modulate these cytokines in an anti-inflammatory direction underscores their immunomodulatory potential.

Aims Inflammation plays an essential role in the atherosclerotic process, and chemokines such as monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) seem to play a pivotal role in the pathogenesis of atherosclerosis. A possible common inflammatory basis for the pathogenesis of type 2 diabetes, metabolic syndrome and atherosclerosis has been suggested. In this study we investigated the effect of physical exercise and the HMG-CoA reductase inhibitor pravastatin on peripheral markers of inflammation in subjects with the metabolic syndrome. Methods The study was an unmasked randomized 2×2 factorial trial of 12 weeks duration. Results In the combined exercise groups there was a significant reduction in MCP-1 and IL-8 of 48pg/ml ( P =0.04) and 1.0pg/ml ( P =0.007), respectively, as compared to the combined non-exercise groups. There was also a significant reduction vs baseline of 50pg/ml (33%) ( P =0.002) and 0.35pg/ml (13%) ( P =0.03) for MCP-1 and IL-8, respectively. Changes in MCP-1 were significantly correlated to changes in visceral fat ( r =0.41, P =0.02). Conclusion The protective effect of exercise might in part be due to suppression of the inflammatory process.

SummaryPlatelets may act as inflammatory cells. To study the effects of soluble and cell-bound platelet factors on the expression of several cytokines and related mediators in leukocytes, peripheral blood mononuclear cells (PBMC) were incubated with platelet-free supernatants from SFLLRN-activated platelet-rich plasma (PRP) or SFLLRN-activated PRP in itself. Our main findings were: (i) the gene expression of several chemokines and some cytokines were markedly increased by both activated PRP and supernatants, as also confirmed at the protein level for IL-6, IL-8 and MIP-1α; (ii) the selective protein kinase A type I (PKAI) antagonist Rp-8-Br-cAMP reduced this platelet-induced expression of IL-6, IL-8 and MIP-1α in PBMC, suggesting a role of cAMP/PKAI mediated mechanisms in this interaction; (iii) PGE2 dose-dependently increased the release of IL-6, IL-8 and MIP-1α from PBMC mimicking the effect of activated platelets. Furthermore, activated platelets released comparable amounts of PGE2, suggesting that platelet-derived PGE2 could interact with PBMC in co-cultures; (iv) IL-10 inhibited the platelet-inducing effect on IL-6, IL-8 and MIP-1α in PBMC, and notably, the addition PGE2 totally abolished this IL-10 effect suggesting that the suppressive effect of IL-10 on the plateletinduced activation of PBMC might at least partly involve PGE2related mechanisms. The present study supports a view of platelets as inflammatory cells, and suggests a potential role of platelet-derived PGE2 in platelet-induced inflammatory responses.

Accumulating evidence indicates that inflammatory cytokines play a pathogenic role in congestive heart failure (CHF) by influencing heart contractility, inducing hypertrophy, and promoting apoptosis or fibrosis, contributing to the continuous myocardial remodeling process. While several stimuli may be operating such as heat-shock protein, microbial antigen, bacterial lipopolysaccharide, shear and oxidative stress, hypoxia and oxidized low-density lipoprotein (LDL), it seems that the inflammatory response to these stimuli may represent a common final pathogenic pathway in CHF regardless of the initial event. Traditional cardiovascular drugs seem to have little influence on the overall cytokine network, and immunomudulatory therapy has emerged as a possible new treatment modality in CHF. Several animal studies, and some clinical pilot studies, have suggested that down-regulation of inflammatory cytokines may improve cardiac performance. On the other hand, preliminary results from the placebo-controlled studies suggest no effect, or even adverse effect, of antitumor necrosis factor (TNF) therapy on mortality and hospitalization. Although somewhat disappointing, these negative results do not necessarily argue against the 'cytokine hypothesis'. These studies just underscore the difficulties and the challenges in developing treatment modalities that can modulate the cytokine network in CHF patients resulting in anti-inflammatory and beneficial net effects. Further research in this area will have to more precisely identify the most important actors in the immunopathogenesis of CHF in order to develop more specific immunomodulating agents for this disorder. However, at present the beneficial role of anticytokine therapy in patients with CHF remains unproven.

Background 3-thia fatty acids such as tetradecylthioacetic acid (TTA) are modified fatty acids that have been suggested to change the plasma profile from atherogenic to cardio protective. Because of its interaction with peroxisome proliferator activated receptor (PPAR) we hypothesized that TTA also could have immunomodulatory properties. Based on the suggested role of inflammation in atherogenesis, any immunomodulating effects of TTA would be of particular interest for the potential use of this fatty acid in atherosclerotic disorders. Materials and methods We examined if TTA could modulate proliferation and the release of cytokines from peripheral mononuclear cells (PBMCs) taken from five healthy blood donors. Results Our main findings were: (i) TTA had several effects on cytokine release from activated PBMCs with a marked increase in interleukin (IL)-10 accompanied by a reduction in IL-2 possibly favouring anti-inflammatory net effects. (ii) These cytokine-modifying effects were found in both T cells and monocytes when cultured separately. (iii) Tetradecylthioacetic acid increased the cytokine stimulating effects of tumour necrosis factor α with a particularly enhancing effect on IL-10. (iv) Tetradecylthioacetic acid significantly suppressed PBMC proliferation, and this antiproliferative property did not involve enhanced apoptosis or necrosis. (v) These immunomodulatory effects of TTA were accompanied by a marked down-regulation of PPARoad mRNA expression, the most abundant PPAR subtype in PBMCs. Conclusions Our findings show potent immunomodulatory effects of TTA in activated PBMCs, possibly involving PPAR-related mechanisms.

Objectives: Biomarkers for diagnosis and therapy efficacy in tuberculosis (TB) are requested. We have studied biomarkers that may differentiate between active and latent TB infection (LTBI), the influence of HIV infection and changes during anti-TB chemotherapy. Methods: Thirty-eight plasma cytokines, assessed by multiplex and enzyme immunoassays, were analyzed in patients with active TB before and during 24 weeks of anti-TB chemotherapy (n = 65), from individuals with LTBI (n = 34) and from QuantiFERON-TB (QFT) negative controls (n = 65). The study participants were grouped according to HIV status. Results: Plasma levels of the CXC chemokine IP-10 and soluble TNF receptor type 2 (sTNFr2) significantly differentiated active TB from the LTBI group, irrespective of HIV status. In the HIV-infected group the sensitivity and specificity was 100% for IP-10 with a cut-off of 2547 pg/mL. Plasma IP-10 declined gradually during anti-TB chemotherapy (12–24 weeks, p = 0.002) to a level comparable to LTBI and QFT negative control groups. sTNFr2 fluctuated throughout therapy, but was decreased after 12–24 weeks (p = 0.006). Conclusions: IP-10 distinguished with high accuracy active TB from LTBI irrespective of HIV infection and declined during anti-TB chemotherapy. Plasma IP-10 may serve as a diagnostic biomarker to differentiate between the stages of TB infection and for monitoring therapy efficacy. ª 2015 The Authors. Published by Elsevier Ltd on behalf of the The British Infection Association. This is an open access article under the CC BY-NC-SA license (http://creativecommons.org/licenses/by-nc-sa/4.0/).

Background The pathogenesis of atherosclerosis and acute coronary syndromes involves inflammation and immunological mechanisms. We hypothesized that patients with unstable angina may have an imbalance between inflammatory and anti-inflammatory cytokines. Design Plasma levels of tumour necrosis factor (TNF)alpha and interleukin (IL)-10 were analyzed in 44 patients with stable angina, 29 patients with unstable angina and 20 controls. mRNA levels of these cytokines were analyzed in peripheral blood mononuclear cells (PBMC). We also studied the in vitro effects of IL-10 in PBMC from unstable angina patients. Results Our main findings were: (1) the angina patients and particularly those with unstable disease had significantly raised TNFalpha in comparison with the controls, both at the protein and mRNA level; (2) in contrast, the levels of IL-10 were not different in the angina patients in comparison with the healthy controls, resulting in a markedly enhanced TNFalpha:IL-10 ratio, particularly in the unstable angina patients; (3) while exogenously added IL-10 markedly inhibited the release of TNFalpha, IL-8 and tissue factor as well as impairing the gelatinolytic activity and mRNA production of matrix metalloproteinase-9, it enhanced the tissue inhibitor of this metalloproteinase (i.e. TIMP-1) in PBMC from the unstable angina patients. Conclusion Patients with unstable angina appear to have an imbalance between TNFalpha and IL-10, possibly favouring inflammatory net effects. IL-10 may have beneficial effects on mechanisms that are important in plaque rupture and thrombus formation.

Background — Chemokines play a pathogenic role in atherogenesis and plaque destabilization by activating and directing leukocytes into the atherosclerotic plaque. However, stromal cell–derived factor (SDF)-1 was recently found to have antiinflammatory effects, and we hypothesized that this chemokine could play a beneficial role in coronary artery disease. Methods and Results — Plasma levels of SDF-1α were significantly decreased in patients with stable (n=30) and unstable angina (n=30) compared with healthy control subjects (n=20), particularly in those with unstable disease. By flow cytometry and RNase protection assay, we found decreased surface expression but increased gene expression of the SDF-1α receptor CXCR-4 in peripheral blood mononuclear cells (PBMC) from patients with stable angina and patients with unstable angina. In vitro, SDF-1α (500 ng/mL) reduced both unstimulated and endotoxin/mitogen-stimulated mRNA and protein levels of monocyte chemoattractant protein-1, interleukin-8, matrix metalloproteinase-9, and tissue factor while increasing tissue inhibitor of metalloproteinases-1 in PBMC from patients with unstable angina. The SDF-1α–mediated suppression of monocyte chemoattractant protein-1 and interleukin-8 appears to involve cAMP/protein kinase A type I–dependent pathways. Finally, although SDF-1α suppressed the spontaneous release of these inflammatory mediators in unstable angina, enhancing effects were seen in unstimulated PBMC from healthy control subjects, possibly reflecting that PBMC in unstable angina are preactivated in vivo. Conclusions — In contrast to several other chemokines, our findings suggest that SDF-1α, at least in high concentrations, may mediate antiinflammatory and matrix-stabilizing effects in unstable angina. These effects may promote plaque stabilization, and therapeutic intervention that enhances SDF-1α activity could potentially be beneficial in acute coronary syndromes.

Objective: Inflammation may play a pathogenic role in chronic heart failure (CHF). The objective of the study was to characterise the imbalance in the cytokine network in CHF. Methods: cDNA expression arrays were used to analyse the gene expression of cytokines and related mediators in peripheral blood mononuclear cells (PBMC) from CHF patients ( n =8) and healthy controls ( n =8). Real-time quantitative reverse transcription–polymerase chain reaction (RT-PCR) was used to determine the gene expression of individual genes in additional 12 patients and eight controls. Results: From 375 genes, 34 were upregulated and two downregulated in CHF patients in the cDNA expression array experiments. Regulated genes included chemokines/-receptors, members of the transforming growth factor β superfamily, orphan receptors and in particular several members of the tumor necrosis factor (TNF) superfamily. Thus, 4-1BB ligand (L), APRIL, CD27L, CD40L, FasL, LIGHT, TRAIL-receptor 4 were upregulated, while TRAIL-receptor 3 was downregulated. Real-time quantitative RT-PCR confirmed significantly upregulated gene expression of APRIL, LIGHT, FasL and CD27L in CHF patients and showed in addition significantly enhanced gene expression of TNFα and TRAIL. Conclusion: The present study demonstrates differential gene expression in PBMC of several members of the cytokine network in CHF. In particular, the enhanced expression of several ligands in the TNF superfamily may reflect a potential pathogenic role of these cytokines in CHF.

Background Enhanced generation of reactive oxygen species and increased oxidative-induced DNA damage have been identified as possible contributors to atherosclerosis. The base excision repair (BER) pathway is the principal mechanism by which mammalian cells repair oxidative DNA damage. BER deficiency can potentially accelerate atherogenesis. Methods We evaluated the association of Single Nucleotide Polymorphisms (SNPs) in genes encoding four different BER proteins (NEIL3, OGG1, APEX1 and XRCC1) with the incidence of myocardial infarction in a nested case–control study among participants of the second survey of the HUNT Study. The study population included 1624 cases and 4087 age- and sex-matched controls. Results For the NEIL3 SNP rs12645561, the TT genotype was associated with increased risk of MI (OR 1.47, 95% CI 1.02–2.12, p uncorrected for multiple comparisons = 0.04) both in the genotypic test (compared to the CC genotype) and in the recessive genetic model (compared to the CC and CT genotypes combined). For the other two NEIL3 SNPs (rs10013040 and rs1395479) and for the SNPs of OGG1 (rs1052133), APEX1 (rs1878703) and XRCC1 (rs25489) we observed no association with risk of myocardial infarction. Conclusion We found that the NEIL3 rs12645561 SNP TT genotype was associated with increased risk of myocardial infarction. If confirmed in other studies, this association may suggest a possible role of attenuated DNA repair, and NEIL3 in particular, in atherogenesis.

Summary Objectives Scrub typhus is endemic in the Asia-Pacific region. Mortality is high even with treatment, and further knowledge of the immune response during this infection is needed. This study was aimed at comparing plasma levels of monocyte/macrophage and endothelial related inflammatory markers in patients and controls in South India and to explore a possible correlation to disease severity and clinical outcome. Methods Plasma levels of ALCAM, VCAM-1, sCD163, sCD14, YKL-40 and MIF were measured in scrub typhus patients ( n = 129), healthy controls ( n = 31) and in infectious disease controls ( n = 31), both in the acute phase and after recovery, by enzyme immunoassays. Results Patients had markedly elevated levels of all mediators in the acute phase, differing from both healthy and infectious disease controls. During follow-up levels of ALCAM, VCAM-1, sCD14 and YKL-40 remained elevated compared to levels in healthy controls. High plasma ALCAM, VCAM-1, sCD163, sCD14, and MIF, and in particular YKL-40 were all associated with disease severity and ALCAM, sCD163, MIF and especially YKL-40, were associated with mortality. Conclusions Our findings show that scrub typhus is characterized by elevated levels of monocyte/macrophage and endothelial related markers. These inflammatory markers, and in particular YKL-40, may contribute to disease severity and clinical outcome.

Chemokines control the migration of leukocytes to inflamed tissue, and in particular monocyte chemoattractant protein (MCP)-1 has been implicated in the pathogenesis of several cardiovascular disorders such as chronic heart failure (CHF) and myocarditis. We hypothesised that MCP-1 may directly contribute to an inflammatory response in the cardiomyocytes, and in the present study we examined in adult rat cardiomyocytes: (i) the effect of tumour necrosis factor (TNF)alpha on MCP-1 production, (ii) the effect of MCP-1 on production of other inflammatory cytokines, and (iii) if the anti-inflammatory cytokine interleukin (IL)-10 could suppress any TNFalpha-induced MCP- 1 production.We used enzyme immunoassays, RNase protection assays and slot blot analysis to measure protein and mRNA levels of various cytokines in adult rat cardiomyocyte cultures.(i) We found a approximately 6.4-fold increase of the MCP-1 level accompanied by an increase in MCP-1 mRNA accumulation in cardiomyocyte cultures after TNFalpha stimulation. (ii) In contrast, TNFalpha had no effect on IL-10 and only a modest effect on IL-1beta and IL-6 levels in these cells. (iii) Importantly, MCP-1 stimulated inflammatory response in cardiomyocytes by enhancing IL- 1beta and IL-6 levels in these cells as found at both the protein and mRNA level. (iv) Co-stim-ulation with IL-10 resulted in a approximately 55% reduction in TNFalpha-stimulated MCP-1 levels in cardiomyocyte culture supernatants.The present study demonstrates for the first time that MCP- 1 can directly affect cardiomyocytes, and we introduce MCP-1 as a potential enhancer and IL- 10 as a potential suppresser of inflammatory responses within the myocardium.

Background Studies in different animal models and plasma analyses in humans suggest that members of the interleukin-6 (IL-6) cytokine family may be involved in the pathogenesis of congestive heart failure (CHF). Accordingly, we have examined IL-6-related cytokines in chronic CHF in humans by analysing gene and protein expression in myocardium derived from patients with end-stage heart failure and donor hearts. Methods Gene expression of cytokines/receptors of the IL-6 family was documented in myocardial samples using cDNA array hybridization and RNase protection assays. Immunohistochemistry was used to detect leukaemia inhibitory factor (LIF), IL-6 and glycoprotein 130 (gp130) in myocardial tissues. Results Myocardial gene activity was documented for the majority of IL-6 family cytokines and their receptors. Immunohistochemical analysis localized IL-6, LIF and their common receptor subunit gp130 to myocytes and vascular smooth muscle cells. LIF mRNA levels were enhanced in the left ventricles of CHF patients relative to the left ventricles of donor hearts (patients 4·6 ± 4·7 vs. donors 0·3 ± 0·3, P

OBJECTIVES We sought to study the relationships between chemokines and oxidative stress in acute coronary syndrome. BACKGROUND In view of existing knowledge on the participation of leukocytes and oxidative stress in the pathogenesis of acute coronary syndrome, we hypothesized that chemokines may play a role in recruiting and activating leukocytes in this disorder. METHODS The levels of chemokines and oxidative stress were studied in 38 patients with stable and 38 with unstable angina and in 20 controls. In separate in vitro experiments the effect of chemokines on reactive oxygen species in monocytes and the effect of antioxidants on chemokine levels in these cells were also studied. RESULTS 1) Angina patients had raised serum levels of chemokines in both cross-sectional and longitudinal testing, with particularly high levels of interleukin (IL)-8, monocyte chemoattractant protein (MCP)-1 and macrophage inflammatory peptide (MIP)-1-alpha in unstable disease. 2) T cells, and particularly monocytes, seem to contribute to the raised IL-8, MCP-1 and MIP-1-alpha levels in unstable angina. 3) Concomitantly, and significantly correlated with MCP-1 and IL-8 levels, stable and particularly unstable angina patients had decreased plasma levels of antioxidants and increased lipid peroxidation, suggesting enhanced oxidative stress. 4) Monocyte chemoattractant protein-1 enhanced the generation of O2−in monocytes from unstable angina patients, and the antioxidant glutathione-monoethyl ester suppressed the production of IL-8 and MCP-1 in these cells. CONCLUSIONS Our findings suggest an interaction between chemokines and oxidative stress in unstable angina. This interaction may represent a vicious circle involved in the pathogenesis of acute coronary syndromes.

Objectives: Chemokines regulate several biological processes, such as chemotaxis, collagen turnover, angiogenesis and apoptosis. Based on the persistent immune activation with elevated circulating levels of chemokines in patients with congestive heart failure (CHF), we have hypothesised a pathogenic role for chemokines in the development of CHF. The objective of this study was to examine mRNA levels and cellular localisation of chemokines and chemokine receptors in human CHF. Methods: We examined explanted hearts from ten patients with end-stage heart failure (all chambers) and in ten organ donors using an RNase protection assays and immunohistochemical techniques. Results: Our main findings were: (i) expression of eight chemokine and nine chemokine receptor genes in both failing and nonfailing myocardium, (ii) particularly high mRNA levels of monocyte chemoattractant protein (MCP)-1 and CXC-chemokine receptor 4 (CXCR4), in both chronic failing and nonfailing myocardium, (iii) decreased mRNA levels of MCP-1 and interleukin (IL)-8 in the failing left ventricles compared to failing left atria, (iv) decreased chemokine (e.g., MCP-1 and IL-8) and increased chemokine receptor (e.g., CCR2, CXCR1) mRNA levels in failing left ventricles and failing left atria compared to corresponding chambers in the nonfailing hearts and (v) immunolocalisation of MCP-1, IL-8 and CXCR4 to cardiomyocytes. Conclusion: The present study demonstrates for the first time chemokine and chemokine receptor gene expression and protein localisation in the human myocardium, introducing a new family of mediators with potentially important effects on the myocardium. The observation of chemokine dysregulation in human end-stage heart failure may represent a previously unknown mechanism involved in progression of chronic heart failure.

Objectives: The purpose of the present study was to examine the circulating levels of CXC-chemokines in patients with various degree of congestive heart failure (CHF). Background: CXC-chemokines may be important mediators in the persistent immune activation observed in CHF patients by activation of circulating neutrophils, T-cells and monocytes and possibly by the recruitment of these cells into the failing myocardium. Methods: Levels of interleukin (IL)-8, growth-regulated oncogene (GRO)α and epithelial neutrophil activating peptide (ENA)-78 were measured both in serum and in platelet-free plasma by enzyme immunoassay in 47 patients with CHF and in 20 healthy controls. Results: (i) CHF patients had significantly elevated levels of all the three CXC-chemokines with IL-8 and GROα showing a gradual increase along with increasing NYHA class. (ii) There was an inverse correlation between IL-8 and left ventricular ejection fraction (EF) and cardiac index (CI). (iii) Both unstimulated and lipopolysaccharide (LPS)-stimulated monocytes from CHF patients released markedly elevated amounts of all three CXC-chemokines. (iv) Platelets from patients with severe CHF were characterised by decreased content of GROα and ENA-78 as well as decreased release of these chemokines upon thrombin receptor stimulation. (v) Activated platelets stimulated peripheral blood mononuclear cells in vitro to enhanced release of IL-8, and neutralising antibodies against ENA-78 inhibited this interaction. Conclusions: This study demonstrates for the first time elevated levels of CXC-chemokines in CHF, which may be of importance for progression of heart failure. Our findings further suggest that activated monocytes and platelets may contribute to enhanced CXC-chemokine levels in CHF.

The simplistic view of atherosclerosis as a disorder of pathologic lipid deposition has been redefined by the more complex concept of an ongoing inflammatory response ([1][1]). Several cellular components seem to participate in this persistent inflammation, such as macrophages, vascular smooth

Competition for iron is a critical component of successful bacterial infections, but the underlying in vivo mechanisms are poorly understood. We have previously demonstrated that lipocalin 2 (LCN2) is an innate immunity protein that binds to bacterial siderophores and starves them for iron, thus representing a novel host defense mechanism to infection. In the present study we show that LCN2 is secreted by the urinary tract mucosa and protects against urinary tract infection (UTI). We found that LCN2 was expressed in the bladder, ureters, and kidneys of mice subject to UTI. LCN2 was protective with higher bacterial numbers retrieved from bladders of Lcn2-deficient mice than from wild-type mice infected with the LCN2-sensitive Escherichia coli strain H9049. Uropathogenic E. coli mutants in siderophore receptors for salmochelin, aerobactin, or yersiniabactin displayed reduced fitness in wild-type mice, but not in mice deficient of LCN2, demonstrating that LCN2 imparts a selective pressure on bacterial growth in the bladder. In a human cohort of women with recurrent E. coli UTIs, urine LCN2 levels were associated with UTI episodes and with levels of bacteriuria. The number of siderophore systems was associated with increasing bacteriuria during cystitis. Our data demonstrate that LCN2 is secreted by the urinary tract mucosa in response to uropathogenic E. coli challenge and acts in innate immune defenses as a colonization barrier that pathogens must overcome to establish infection. © 2014 by The American Association of Immunologists, Inc. This is a published Author Choice article (paid immediate Open Access). The definitive published version is available at https://doi.org/10.4049/jimmunol.1401528

Background: Based on their essential role in concerting immunological and inflammatory responses we hypothesized that the homeostatic chemokines CCL19 and CCL21 may play a pathogenic role in rickettsiae infection. Methods: Serum levels of CCL19 and CCL21 in patients with R. africae and R. conorii infection were analyzed by enzyme immunoassays. Lungs from R. conorii infected mice were examined for CCL19, CCL21 and CCR7 expression by immunohistochemistry. Results: We found that patients with R. africae infection (n = 15) and in particular those with R. conorii infection (n = 16) had elevated serum levels of CCL19 on admission, with a decline during follow-up. While a similar pattern was seen for CCL21 in R. africae infection, patients with R. conorii infection showed persistently increased CCL21 levels during follow-up. In experimental R. conorii infection, we found strong immunostaining of CCL19 and CCL21 in the lungs, particularly in individuals that had received lethal doses. Immunofluorescence showed co-localization of CCR7 to endothelial cells, macrophages and fibroblasts within the lung tissue of R. conorii infected mice. Conclusions: Our findings suggest that the CCL19/CCL21/CCR7 axis is up-regulated during R. africae and in particular during R. conorii infection, which may potentially contribute to the pathogenesis of these disorders. © 2014 Astrup et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Background: Recent studies link Toll-like receptor 3 (TLR3) to the pathogenesis of inflammatory bowel disease (IBD). Screening TLR3-agonist response in an intestinal epithelial cell line, we found complement factor B mRNA (CFB) potently upregulated and went on to further study localization of complement factor B synthesis and systemic activation of complement in ulcerative colitis and Crohn's disease. Methods: In a transcriptome analysis of poly (I:C) stimulated HT-29 cells, we found CFB highly upregulated downstream of TLR3. We sought to confirm CFB upregulation in a microarray gene expression analysis on colonic biopsies from an IBD population (n = 133). Immunohistochemical staining and in situ hybridization were done to identify cellular sources of factor B and CFB. Systemic complement activation was assessed in plasma (n = 18) using neoepitope-based enzyme linked immunosorbent assay. Results: CFB mRNA and protein were abundantly expressed in the colonic epithelial cell line, and synthesis enhanced by the poly (I:C) TLR3 ligand. In inflamed versus normal colonic mucosa of ulcerative colitis and Crohn's disease, CFB mRNA was the most significantly overexpressed gene and the mRNA abundance ratio was among the 50 highest. Epithelial cells were the dominating site of factor B expression. Systemic complement activation was significantly higher in active than in nonactive IBD. Conclusions: This study is the first to link TLR3 to activation of the alternative complement pathway. Complement factor B is potently upregulated locally in IBD in addition to having a possible central role in systemic complement activation. This suggests a prominent role for complement in IBD pathogenesis. This is a submitted manuscript of an article published by Lippincott, Williams & Wilkins for Crohn's & Colitis Foundation of America, Inc. in Inflammatory Bowel Diseases, 2014

Background: In inflammatory bowel disease (IBD), genetic susceptibility together with environmental factors disturbs gut homeostasis producing chronic inflammation. The two main IBD subtypes are Ulcerative colitis (UC) and Crohn’s disease (CD). We present the to-date largest microarray gene expression study on IBD encompassing both inflamed and uninflamed colonic tissue. A meta-analysis including all available, comparable data was used to explore important aspects of IBD inflammation, thereby validating consistent gene expression patterns. Methods: Colon pinch biopsies from IBD patients were analysed using Illumina whole genome gene expression technology. Differential expression (DE) was identified using LIMMA linear model in the R statistical computing environment. Results were enriched for gene ontology (GO) categories. Sets of genes encoding antimicrobial proteins (AMP) and proteins involved in T helper (Th) cell differentiation were used in the interpretation of the results. All available data sets were analysed using the same methods, and results were compared on a global and focused level as t-scores. Results: Gene expression in inflamed mucosa from UC and CD are remarkably similar. The meta-analysis confirmed this. The patterns of AMP and Th cell-related gene expression were also very similar, except for IL23A which was consistently higher expressed in UC than in CD. Un-inflamed tissue from patients demonstrated minimal differences from healthy controls. Conclusions: There is no difference in the Th subgroup involvement between UC and CD. Th1/Th17 related expression, with little Th2 differentiation, dominated both diseases. The different IL23A expression between UC and CD suggests an IBD subtype specific role. AMPs, previously little studied, are strongly overexpressed in IBD. The presented meta-analysis provides a sound background for further research on IBD pathobiology. © 2013 Granlund et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Progressive HIV infection is characterized by profound enterocyte damage, microbial translocation and chronic immune activation. We aimed to test whether High Mobility Group Box protein 1(HMGB1), a marker of cell death, alone, or in combination with LPS, might contribute to HIV-associated immune activation and progression. Altogether, 29 untreated HIV-infected individuals, 25 inflammatory bowel disease (IBD) patients and 30 controls were included. HIV-infected patients had lower plasma LPS levels than IBD patients, but higher levels of soluble CD14 and Myeloid Differentiation (MD) 2, which interacts with TLR4 to initiate LPS-signalling. Furthermore, plasma levels of HMGB1 and MD2 were correlated directly within the HIV-infected cohort (r = 0.89, P

New drugs for rheumatoid arthritis (RA) have resulted in an improvement in patients' functioning and morbidity, but are linked with increased risk of infections. Traditional immunosuppressant drugs are often used in combination with anti-tumour necrosis factor-alpha (TNF-α) inhibitors or anti-CD20 (rituximab).The review is based on a search in PubMed and on the authors' own experience of treating infections in patients who receive immunosuppressant treatment.Traditional immunomodulating treatment results in an increased risk of infection. The disease RA in itself increases the risk of infections. There is evidence of an increased incidence of infections with both extracellular bacteria and intracellular microorganisms such as mycobacteria, including Mycobacterium tuberculosis, and viruses in patients who are treated with TNF-α inhibitors. Patients who are about to start taking TNF-α inhibitors must therefore undergo a tuberculosis-risk assessment. Rituximab may increase the incidence of infection, but long-term observations are limited. Combination therapy involving different drugs that selectively modulate immune response is normally contraindicated because of the increased risk of infection.The benefit of TNF-α inhibitors and rituximab treatment for RA must be weighed up against the increased risk of infections. Symptoms, findings and laboratory test results pertaining to serious infections may be influenced by immunomodulation therapy and thereby make clinical assessment difficult.

Summary Based on the ability to recruit lymphocytes and dendritic cells to lymphoid tissue and to promote inflammation, we hypothesized a role for dysregulated CCL19 and CCL21 levels in human immunodeficiency virus (HIV)-infected patients with advanced immunodeficiency, and in particular in those with accompanying Mycobacterium avium complex (MAC) infection. The hypothesis was explored by studies in HIV-infected patients with and without MAC infection, as well as in vitro, examining the ability of proteins from MAC to promote CCL19 and CCL21 responses in peripheral blood mononuclear cells (PBMC) during highly active anti-retroviral therapy (HAART). Our main findings were: (i) raised serum levels of CCL19 in HIV-infected patients with CD4+ T cell count 500 cells/µl and healthy controls, with particularly high levels in those with MAC infection; (ii) elevated plasma levels of CCL19 predicted a higher mortality in acquired immune deficiency syndrome (AIDS)-patients, independent of ongoing MAC infection; and (iii) marked production of CCL19 in MAC-stimulated peripheral blood mononuclear cells (PBMC) and pronounced disturbances in MAC-induced CCL19 production in PBMC from HIV patients that was partly reversed during HAART. Our findings suggest the involvement of CCL19 in AIDS patients with advanced immunodeficiency, potentially mediating both adaptive and maladaptive responses.

The pathophysiological hallmark of spotted fever group rickettsioses comprises vascular inflammation. Based on the emerging importance of the wingless (Wnt) pathways in inflammation and vascular biology, we hypothesized that Dickkopf-1 (DKK-1), as a major modulator of Wnt signaling, could be involved in the pathogenesis in rickettsial infections. Our major findings were: (i) While baseline concentration of DKK-1 in patients with R. conorii infection (n = 32) were not different from levels in controls (n = 24), DKK-1 rose significantly from presentation to first follow-up sample (median 7 days after baseline). (ii) In vitro experiments in human umbilical vein endothelial cells (HUVECs) showed that while heatinactivated R. conorii enhanced the release of interleukin-6 (IL-6) and IL-8, it down-regulated the release of endothelialderived DKK-1 in a time- and dose-dependent manner. (iii) Silencing of DKK-1 attenuated the release of IL-6, IL-8 and growth-related oncogene (GRO)a in R. conorii-exposed HUVECs, suggesting inflammatory effects of DKK-1. (iv) Silencing of DKK-1 attenuated the expression of tissue factor and enhanced the expression of thrombomodulin in R. conorii-exposed HUVECs suggesting pro-thrombotic effects of DKK-1. The capacity of R. conorii to down-regulate endothelial-derived DKK-1 and the ability of silencing DKK-1 to attenuate R. conorii-induced inflammation in endothelial cells could potentially reflect a novel mechanism by which R. conorii escapes the immune response at the site of infection. © 2012 Antonov et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Background: CCL19 and CCL21, acting through CCR7, are termed homeostatic chemokines. Based on their role in concerting immunological responses and their proposed involvement in tissue remodeling, we hypothesized that these chemokines could play a pathogenic role in heart failure (HF). Methodology/Principal Findings: Our main findings were: (i) Serum levels of CCL19 and particularly CCL21 were markedly raised in patients with chronic HF (n = 150) as compared with healthy controls (n = 20). A CCL21 level above median was independently associated with all-cause mortality. (ii) In patients with HF following acute myocardial infarction (MI; n = 232), high versus low CCL21 levels 1 month post-MI were associated with cardiovascular mortality, even after adjustment for established risk factors. (iii). Explanted failing human LV tissue (n = 29) had markedly increased expression of CCL21 as compared with non-failing myocardium (n = 5). (iv) Our studies in CCR7−/− mice showed improved survival and attenuated increase in markers of myocardial dysfunction and wall stress in post-MI HF after 1 week, accompanied by increased myocardial expression of markers of regulatory T cells. (v) Six weeks post-MI, there was an increase in markers of myocardial dysfunction and wall stress in CCR7 deficient mice. Conclusions/Significance: High serum levels of CCL21 are independently associated with mortality in chronic and acute post-MI HF. Our findings in CCR7 deficient mice may suggest that CCL21 is not only a marker, but also a mediator of myocardial failure. However, while short term inhibition of CCR7 may be beneficial following MI, a total lack of CCR7 during long-term follow-up could be harmful. publishedVersion

presence of myofibroblasts in all layers of the intestinal wall. Ulcerative colitis (UC) is classically considered to be a purely mucosal disease although rarely transmural complications such as strictures and stenosis develop. Fibrogenesis in UC has not been studied systematically yet and may be a neglected phenomenon. We therefore investigated whether there is a different fibrotic load in acute vs longstanding UC and whether the degree of fibrosis in UC correlates with the severity of inflammation. Methods: Colectomy specimens from all UC patients operated at the AMC between 2007 2012 were reviewed. Specimens from patients with recent onset refractory therapy UC (diagnosis 10 years) were selected. Patients operated for colon cancer without UC served as controls. On HE 29% vs 33% vs 54%, p = 0.009). Between acute and late UC there was no difference in collagen deposition, however between UC together and controls there was more collagen I expression in the mucosa, MM and muscularis externa (50% vs 10%, p = 0.02; 28% vs 10%, p = 0.048; 71% vs 20%, p = 0.003). In both early and long UC duration, we did not find a correlation between inflammation or collagen deposition or MM thickness. There was a negative correlation between inflammation and aSMA positivity in the submucosa (R = 0.51, p = 0.003) and MM (R = 0.37, p = 0.04). Conclusions: In our series of colectomy specimens, there is more collagen deposition in UC than in controls. No association between disease duration and increased collagen deposition could be found. Expression of aSMA however is lower in UC and correlates with inflammation. Fibrosis in UC does not appear to increase significantly over time.

Context: Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in Western and non-Western countries, but its pathogenesis is not fully understood. Objective: Based on the role of nicotinamide phosphoribosyltransferase (NAMPT) in fat and glucose metabolism and cell survival, we hypothesized a role for NAMPT/visfatin in the pathogenesis of NAFLD-related disease. Design and Setting: We conducted clinical studies at a referral medical center in well-characterized NAFLD patients (n = 58) and healthy controls (n = 27). In addition we performed experimental in vitro studies in hepatocytes. Main Outcome Measures: We examined 1) the hepatic and systemic expression of NAMPT/visfatin in patients with NAFLD and control subjects, 2) the hepatic regulation of NAMPT/visfatin, and 3) the effect of NAMPT/visfatin on hepatocyte apoptosis. Results: Our main findings were as follows. 1) Patients with NAFLD had decreased NAMPT/visfatin expression both systemically in serum and within the hepatic tissue, with no difference between simple steatosis and nonalcoholic steatohepatitis. 2) By studying the hepatic regulation of NAMPT/visfatin in wild-type and peroxisome proliferators-activated receptor (PPAR)α−/− mice as well as in hepatocytes, we showed that PPARα activation and glucose may be involved in the down-regulation of hepatic NAMPT/visfatin expression in NAFLD. 4) Within the liver, NAMPT/visfatin was located to hepatocytes, and our in vitro studies showed that NAMPT/visfatin exerts antiapoptotic effects in these cells, involving enzymatic synthesis of nicotinamide adenine dinucleotide. Conclusion: Based on these findings, we suggest a role for decreased NAMPT/visfatin levels in hepatocyte apoptosis in NAFLD-related disease.

Numerous clinical studies have established that tumor necrosis factor (TNF)-α may play a pathogenic role in the development and progression of heart failure (HF). Recent reports suggest that other ligands in the TNF superfamily could also play a pathogenic role in chronic HF. TNF superfamily ligands are expressed predominantly by cells in the immune system, while the TNF receptor superfamily are expressed by a wide variety of cells, including myocardial cells. Several pathways are activated by ligand–receptor interactions, but of particular importance is the nuclear factor (NF)-κB pathway which is activated in the failing human heart. All ligands in the TNF superfamily have the potential to activate NF-κB, leading to transcription of genes involved in apoptosis, cell survival, proliferation, inflammation and hypertrophic signaling in cardiomyocytes. Among several TNF superfamily members that are activated in HF, the authors’ have recentlyshown that CD40L–CD40 and OPG–RANK–RANKL interactions may be implicated in the pathogenesis of HF through different mechanisms, possibly representing new targets for therapy in this disorder.

Activin A, a member of the transforming growth factor (TGF)-β superfamily, is involved in regulation of tissue remodeling and inflammation. Herein, we wanted to explore a role for activin A in pulmonary hypertension (PH). Circulating levels of activin A and its binding protein follistatin were measured in patients with PH ( n = 47) and control subjects ( n = 14). To investigate synthesis and localization of pulmonary activin A, we utilized an experimental model of hypoxia-induced PH. In mouse lungs, we also explored signaling pathways that can be activated by activin A, such as phosphorylation of Smads, which are mediators of TGF-β signaling. Possible pathophysiological mechanisms initiated by activin A were explored by exposing pulmonary arterial smooth muscle cells in culture to this cytokine. Elevated levels of activin A and follistatin were found in patients with PH, and activin A levels were significantly related to mortality. Immunohistochemistry of lung autopsies from PH patients and lungs with experimental PH localized activin A primarily to alveolar macrophages and bronchial epithelial cells. Mice with PH exhibited increased pulmonary levels of mRNA for activin A and follistatin in the lungs, and also elevated pulmonary levels of phosphorylated Smad2. Finally, we found that activin A increased proliferation and induced gene expression of endothelin-1 and plasminogen activator inhibitor-1 in pulmonary artery smooth muscle cells, mediators that could contribute to vascular remodeling. Our findings in both clinical and experimental studies suggest a role for activin A in the development of various types of PH.

Soluble proteins that bind LPS, like myeloid differentiation-2 (MD-2) and CD14, have essential roles in regulating LPS signaling through TLR4. During a Gram-negative bacterial infection, the host may control the response by adjusting the levels of soluble MD-2 and CD14. To address the surface expression of MD-2 on human leukocytes, we developed a mAb, IIC1, that recognized MD-2 both free and when bound to TLR4. MD-2 was found on the surface of freshly isolated monocytes, on a subpopulation of CD19+ B-cells and on CD15+ neutrophils. LPS transiently reduced the MD-2 levels on monocytes, which is most likely due to endocytosis of the LPS receptor complex since MD-2 colocalized with TLR4 in early endosomes after LPS stimulation. In the absence of LPS, MD-2 partly colocalized with TLR4 in Golgi trans and medial compartments. Cultivating monocytes for 18–20 h resulted in loss of MD-2 expression on the surface, which was reversed either by LPS or IL-10. Furthermore, addition of IL-10, but not LPS, resulted in a considerable increase in mRNA for both MD-2 and CD14. Using ELISA, we demonstrated that IL-10 had a profound dose- and time-related effect on the release of soluble MD-2 and soluble CD14 from monocytes. In HIV-infected patients, the amounts of MD-2, CD14, and IL-10 increased significantly in the patient group with AIDS. Of interest, we found that IL-10, CD14, and MD-2 levels were positively correlated, suggesting that IL-10 may be a driving force for increased release of MD-2 and CD14 during systemic inflammation.

The CCR7 ligands, CCL19 and CCL21, coordinate lymph node homing of naive and central memory T cells. In untreated HIV-infected patients, serum levels of CCL19 and CCL21 showed a biphasic pattern during progression; a marked increase was followed by a decline in patients with advanced immunodeficiency. During highly active antiretroviral therapy, a decrease in CCL19/CCL21 levels was restricted to virologic responders. We suggest that dysregulation of CCR7 ligands may play an important role in progression of HIV infection.

Summary Objectives Mediterranean spotted fever (MSF) caused by Rickettsia conorii ( R. conorii ) is a potential lethal disease while African tick bite fever (ATBF) caused by Rickettsia africae is a self-limiting flu-like illness. We hypothesized that different inflammatory potential in endothelial cells could contribute to the different clinical features in these rickettsioses. Methods We analyzed the effect of heat-inactivated R. africae and R. conorii on the mRNA and protein levels of monocyte chemoattractant protein (MCP)-1, interleukin (IL)-8 and adhesion molecules in endothelial cells. Serum samples from patients with MSF ( n =16) and ATBF ( n =15) were collected before and after therapy. Results R. conorii induced a marked increase in MCP-1, IL-8, and adhesion molecules in endothelial cells, involving toll-like receptor 4 activation. In contrast, R. africae induced MCP-1 expression, but only modest or no responses were seen on IL-8 and adhesion molecules. Comparable to the in vitro response, levels of IL-8 and adhesion molecules showed no or only a modest increase in ATBF patients while these inflammatory markers were markedly elevated during MSF. Conclusions Our findings suggest a superior inflammatory potential of R. conorii as compared to R. africae in endothelial cells, potentially related to the more severe inflammation in MSF comparing ATBF.

Common variable immunodeficiency (CVID) is a heterogeneous syndrome characterized by defective immunoglobulin production and high frequency of bacterial infections, autoimmunity and manifestations of chronic inflammation. The chemokine Fractalkine (CX3CL1) and its receptor CX3CR1 is suggested to play an important role in the pathogenesis of several inflammatory disorders. We hypothesized that enhanced CX3CL1/CX3CR1 interaction could be involved in the chronic inflammation characterising subgroups of CVID. CVID patients were characterized by raised plasma levels of CX3CLl and enhanced expression of its corresponding receptor CX3CR1 on CD4(+) and CD8(+) T cells, including both CD45RA(+) and CD45RA(-) subsets. CX3CR1 expression was particularly enhanced in patients characterized by chronic inflammation in vivo. The high expression of the receptor in CVID patients was accompanied by enhanced chemotactic, adhesive, and other inflammatory cell responses to stimulation with CX3CL1. Our findings suggest that increased CX3CL1/CX3CR1 interaction could contribute to the inflammatory phenotype seen in subgroups of CVID patients.

Inflammation may contribute to the pathogenesis of chronic heart failure. Some reports suggesting that exercise training may have net anti-inflammatory effects in heart failure patients exists, although the results are somewhat conflicting.Fifteen patients with mild to moderate chronic heart failure underwent an exercise training program of 20 weeks. They were examined at baseline, at the end of the training period, and 1 year after end of training.Our main findings were as follows: (i) during the training period there was a significant increase in exercise capacity as estimated by the 6-min walk test as well as an improvement in several quality of life parameters, (ii) these changes were accompanied by a marked decrease in plasma levels of soluble CD40 ligand and P-selectin, probably reflecting an attenuated platelet-mediated inflammation, (iii) in contrast, there were no changes in plasma levels of tumor necrosis factor alpha, monocyte chemoattractant protein-1, or vascular cellular adhesion molecule-1 during the training period, (iv) except for an increase in systolic annular velocity there were no changes in echocardiographic variables during the training period, (v) one year after the training, in a period without systematic training, plasma levels of soluble CD40 ligand, and P-selectin had returned to baseline levels along with a nonsignificant reduction in 6-min walk test.Our findings suggest a potent downregulatory effect of exercise training on platelet-mediated inflammation in patients with chronic heart failure. Further studies are needed to clarify the clinical significance of these findings.

Thrombus formation and inflammation are involved in the pathogenesis of pulmonary arterial hypertension (PAH), and LIGHT (Lymphotoxin-like Inducible protein that competes with Glycoprotein D for Herpesvirus entry mediator on T lymphocytes) has been shown to promote vascular inflammation.We sought to investigate the role of the tumor necrosis factor superfamily ligand LIGHT in the pathogenesis of PAH.We studied 73 patients with severe PAH and 10 control subjects. LIGHT and pro- and antithrombotic markers were assessed by enzyme immunoassays.(1) Patients with idiopathic PAH (n = 21), patients with PAH related to risk factors or associated conditions (n = 31), and those with chronic thromboembolic PAH (n = 21) all had raised serum levels of LIGHT compared with control subjects (n = 10). (2) LIGHT levels in femoral artery were significantly related to mortality in the patients with PAH. (3) Immunostaining of LIGHT and its receptors was seen in alveolar macrophages, vascular smooth muscle cells, and endothelial cells in lungs from patients with PAH. (4) Thirteen patients received prostacyclin infusion (3 mo), and all showed hemodynamic improvement, accompanied by decreased LIGHT levels. (5) Prostacyclin abolished the release of LIGHT from activated platelets in vitro, suggesting that the decrease in LIGHT during prostacyclin therapy could involve direct effects on platelets. (6) LIGHT increased tissue factor and plasminogen activator inhibitor type 1 and decreased thrombomodulin levels in endothelial cells, inducing a prothrombotic state in these cells.Our findings suggest prothrombotic effects of LIGHT in PAH involving endothelium-related mechanisms, potentially contributing to the progression of this disorder.

Objectives: The tumor necrosis factor superfamily member 14, LIGHT (homologous to lymphotoxin, exhibits inducible expression, and competes with HSV glycoprotein D for herpes virus entry mediator (HVEM), a receptor expressed by T lymphocytes), has been involved in various autoimmune disorders and has been shown to influence hepatic lipid metabolism. We hypothesized that LIGHT could also have a pathogenic role in nonalcoholic fatty liver disease (NAFLD). Methods: Serum levels of LIGHT in NAFLD patients and control subjects, as well as LIGHT and interleukin (IL)-8 released from Huh7 (human hepatoma cell line) hepatocytes, were determined by enzyme-linked immunosorbent assay. The mRNA expression of LIGHT in the liver tissue and mRNA levels of LIGHT and IL-8 in Huh7 hepatocytes were assessed by real-time quantitative reverse transcription-PCR. Results: (i) Serum levels of LIGHT were significantly elevated in NAFLD patients (n=66) as compared with healthy controls (n=16), with no differences between simple steatosis (n=34) and nonalcoholic steatohepatitis (NASH) (n=32). (ii) Within the liver, NAFLD patients (n=14) had significantly increased mRNA levels of the two LIGHT receptors, herpes virus entry mediator and lymphotoxin β receptor (LTβR), as compared with controls (n=7), with no difference between simple steatosis (n=8) and NASH (n=6). (iii) LIGHT markedly increased the release of IL-8 in Huh7 hepatocytes in a time- and dose-dependent manner. (iv) The reactive oxygen species (ROS) H2O2 (hydrogen peroxide) enhanced the LIGHT-mediated release of IL-8 in Huh7 hepatocytes. Conclusion: We show increased levels of LIGHT and its two membrane-bound receptors in NAFLD, potentially promoting hepatic inflammation through ROS interaction. Our findings should encourage further studies on the role of LIGHT in NAFLD development and progression. © 2015 the American College of Gastroenterology All rights reserved. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License.

Background and Purpose—Homocysteine has been linked to increased risk of ischemic stroke and other cardiovascular events, but the mechanism by which elevated plasma levels of homocysteine promotes atherogenesis remains unclear. Matrix degradation, partly regulated by the balance between matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs), plays an important role in atherogenesis and plaque destabilization, and we hypothesized an imbalance between MMPs and TIMPs in hyperhomocysteinemia.Methods—Serum MMP-9 and TIMP-1 was measured in 12 hyperhomocysteinemic and 12 control subjects. The release of MMP-9 and TIMP-1, with and without interleukin-10 (IL-10), and the effect of IL-10 on signal transducer and activator of transcription 3 (STAT3) phosphorylation were measured in peripheral blood mononuclear cells (PBMCs) from hyperhomocysteinemic and control subjects.Results—Our main findings were: (1) hyperhomocysteinemic subjects had raised serum levels of MMP-9 and MMP-9/TIMP-1 ratio comparing healthy controls; (2) although IL-10 markedly suppressed MMP-9 release from PBMCs in controls, no or only minor effect was seen in hyperhomocysteinemic subjects; (3) although IL-10 enhanced TIMP-1 levels in PBMCs from both hyperhomocysteinemic and control subjects, the increase was more prominent in controls, resulting in a marked difference in IL-10–induced changes in MMP-9/TIMP-1 ratio between these 2 groups; and (4) comparing PBMCs from controls, cells from hyperhomocysteinemic individuals had impaired IL-10–induced STAT3 phosphorylation.Conclusions—Our findings suggest an attenuated inhibitory response to IL-10 on MMP-9 activity in hyperhomocysteinemic subjects, potentially promoting atherogenesis and plaque instability, representing a novel explanation for increased risk for atherosclerotic disease in these individuals.

Chronic heart failure (CHF) is accompanied by a dysregulated cytokine network, which is characterized by a rise in inflammatory cytokines and an inadequate elevation of anti-inflammatory mediators. This dysregulation has been implicated in the development and progression of CHF and, in the last decade, attempts have been made to modulate this imbalance in the cytokine network. With the exception of one larger mortality/morbidity study, all studies of immunomodulatory therapy in HF conducted to date have included100 patients and the overall experience in this therapeutic area is limited compared with studies of neurohormonal antagonists, which have included several thousand patients. While trials of anti-tumor necrosis factor therapies have thus far failed, recent studies of broad-based immunomodulatory agents (e.g. intravenous immunoglobulin, thalidomide, and pentoxifylline) highlight a potential for such therapy in HF patients, in parallel with optimal cardiovascular treatment regimens. In addition to identifying the crucial factors in the immunopathogenesis of CHF in order to develop novel immunomodulatory treatment strategies, there is a clear need to confirm the results of the smaller studies conducted to date with larger placebo-controlled mortality studies that involve a diverse group of patients, with regard to the cause and severity of HF.

SummaryThe importance of the innate immune system, including mannose-binding lectin and the complement system, in common variable immunodeficiency is unclear. The objective of this study was to evaluate mannose-binding lectin and the complement system in relation to clinical and immunological parameters in patients with common variable immunodeficiency. Circulating levels of mannose-binding lectin, complement components, complement activation products and functional capacity of complement pathways were correlated to clinical features within 71 patients and compared with 30 healthy controls. The main findings were; the patients had signs of increased complement activation significantly associated with signs of autoimmunity and immunological hyperactivity; there were no signs of deficiencies of the classical and alternative complement pathways in the patient group; the prevalence of lectin pathway deficiency was the same in patients and controls, but patients with increased frequency of lower respiratory tract infections or bronchiectasis had lower capacity of the lectin pathway than patients without these features (P = 0·002 and 0·004, respectively); the serum concentration of mannose-binding lectin was inversely correlated to the frequency of lower respiratory tract infections (P = 0·002) and bronchiectasis (P = 0·01). We conclude that patients with common variable immunodeficiency have no increased frequency of complement deficiencies but signs of increased complement activation. Our findings suggest that mannose-binding lectin and the lectin complement pathway may protect against lower respiratory tract infection and bronhiectasis in patients with common variable immunodeficiency.

Understanding of the mechanisms underlying atherosclerotic disorders has evolved beyond the view of a progressive collection of lipids and cellular debris in the vascular wall. Current evidence has implicated inflammatory pathways as an important pathogenic mechanism in atherogenesis and plaque destabilization. Although not necessarily the primary event, inflammation and cytokine activation during plaque formation and destabilization may represent a common final pathway to various stimuli. Thus, it seems that not only 'new' risk factors, such as infections with various microorganisms, but also classic risk factors for cardiovascular disease, such as hyperlipidemia, hypertension and diabetes, may promote their atherogenic effects through inflammatory responses. Indeed, recent reports have suggested that traditional cardiovascular medications may attenuate atherogenesis and enhance plaque stability, at least partly through anti-inflammatory mechanisms. However, uncovering the inflammatory pathways in atherosclerosis has raised the possibility that newer treatment modalities should be more directly targeted against inflammatory mediators. Recently, a series of experimental studies have reported reduction of atherosclerosis by immunomodulatory therapy, such as chemokine blockade, interleukin-10 and immunization/vaccination against oxidized low-density lipoprotein and heat-shock protein. It is conceivable that some of these approaches will be tested clinically and, if successful, they could provide novel treatment strategies in coronary artery disease in humans.

Objective—Increasing data support the involvement of chemokines in atherogenesis. However, although several studies have shown increased chemokine levels in adult patients, the literature is virtually devoid of data on chemokines in children with hypercholesterolemia.Methods and Results—We examined the gene expression of chemokines in peripheral blood mononuclear cells (PBMCs) from clinically healthy children with and without heterozygous familial hypercholesterolemia (FH). Our main findings were: (1) compared with healthy controls, PBMCs from FH children showed significantly higher mRNA levels of RANTES, but not of the other examined chemokines; (2) an opposite pattern was seen in adult FH subjects, with markedly enhanced expression of macrophage inflammatory peptide-1α, but not of RANTES; (3) this increased gene expression of RANTES in PBMCs from FH children seemed to reflect enhanced RANTES expression in monocytes but not in T cells; (4) FH children also had raised serum levels of neopterin, additionally suggesting monocyte/macrophage activation in these children; and (5) PBMCs from both FH children and controls showed enhanced release of interleukin 8 on RANTES stimulation in vitro.Conclusions—Our findings support a role of inflammation also in the early stages of atherogenesis possibly involving monocyte-derived RANTES as an important mediator.

Our understanding of the mechanisms underlying acute coronary syndromes has evolved beyond the view that this syndrome reflects a progressive collection of lipids and cellular debris in the vascular wall. Current evidence has implicated a role for inflammation in the pathogenesis of this process. Thus, inflammatory cytokines may attenuate interstitial collagen synthesis, increase matrix degradation and promote apoptosis in several atheroma-associated cell types, and all these cellular events may enhance plaque vulnerability. Recently, a series of experimental studies have reported the plaque-stabilising effects of immunomodulatory therapy such as chemokine blockade, anti-CD40 ligand and IL-10. It is conceivable that some of these approaches will be tested clinically and, if successful, they could provide novel treatment strategies for atherosclerotic plaque stabilisation.