Nanoparticles activate the NLR pyrin domain containing 3 (Nlrp3) inflammasome and cause pulmonary inflammation through release of IL-1α and IL-1β.

Nanoparticles are increasingly used in various fields, including biomedicine and electronics. One application utilizes the opacifying effect of nano-TiO(2), which is frequently used as pigment in cosmetics. Although TiO(2) is believed to be biologically inert, an emerging literature reports increased incidence of respiratory diseases in people exposed to TiO(2). Here, we show that nano-TiO(2) and nano-SiO(2), but not nano-ZnO, activate the NLR pyrin domain containing 3 (Nlrp3) inflammasome, leading to IL-1β release and in addition, induce the regulated release of IL-1α. Unlike other particulate Nlrp3 agonists, nano-TiO(2)-dependent-Nlrp3 activity does not require cytoskeleton-dependent phagocytosis and induces IL-1α/β secretion in nonphagocytic keratinocytes. Inhalation of nano-TiO(2) provokes lung inflammation which is strongly suppressed in IL-1R- and IL-1α-deficient mice. Thus, the inflammation caused by nano-TiO(2) in vivo is largely caused by the biological effect of IL-1α. The current use of nano-TiO(2) may present a health hazard due to its capacity to induce IL-1R signaling, a situation reminiscent of inflammation provoked by asbestos exposure.

Canakinumab Relieves Symptoms of Acute Flares and Improves Health-Related Quality Of Life (HRQoL) in Difficult-To-Treat Gouty Arthritis Patients by Suppressing Inflammation: Results of a Randomized, Dose-Ranging Study

RATIONALE:We investigated the impact of canakinumab, a fully human anti-interleukin-1b monoclonal antibody on inflammation and HRQoL in gouty arthritis patients.METHODS: In this 8-week, single-blind, dose-ranging study, patients with acute gouty arthritis flares, unresponsive/intolerant or contraindicated to NSAIDs and/or colchicine were randomized to single subcutaneous canakinumab (10, 25, 50, 90, or 150mg, N5143) or single intramuscular triamcinolone acetonide (TA, 40mg, N557). Patients assessed pain (Likert scale), physicians assessed clinical signs of joint inflammation, and HRQoL was recorded using SF-36.RESULTS: At baseline, 98% patients had moderate-to-extreme pain, 85% had moderate/severe joint swelling, 64-79% had elevated inflammatory markers and HRQoL scores indicated impaired physical function. Percentage of patients with no/mild pain was numerically greater in most canakinumab groups vs. TA, 24-72h post-dose; difference significant for 150mg group at these time-points (P<0.05). Canakinumab 150mg was associated with significantly lower Likert scores for tenderness [OR, 3.2; 95% CI, 1.27-7.89; P50.014] and swelling (OR, 2.7; 95% CI, 1.09-6.50, P50.032) at 72h vs. TA; erythema was not different. Median CRP and SAA levels normalized by 7 days post-dose in most canakinumab groups, but remained elevated in TA. Physical function improved at 7 days postdose in all groups, highest improvement for canakinumab 150mg. SF-36 scores for physical functioning and bodily pain with canakinumab 150mg approached US general population scores by 7 days post-dose and exceeded normal values by 8 weeks post-dose.CONCLUSION: Canakinumab 150mg produced significantly greater and rapid pain-relief and improvements in HRQoL vs. TAin acute gouty arthritis patients.

Averting inflammation by targeting the cytokine environment.

Cytokines are key instigators and regulators of immune responses and therefore hold great potential as targets for new therapeutic strategies. However, the selection of which cytokines to target, and in particular the identification of which cytokines regulate the rate-limiting steps of disease pathways, is crucial to the success of such strategies. Moreover, balancing the need for ablating pathological inflammatory responses and simultaneously maintaining the ability to control infectious agents is a key consideration. Recent advances in our understanding of cytokine networks, as well as technical progress in blocking cytokines in vivo, are likely to be a source for new drugs that can control chronic inflammatory diseases.

Intragastric and Intranasal Administration of Lactobacillus paracasei NCC2461 Modulates Allergic Airway Inflammation in Mice.

Introduction. Preclinical and clinical evidences for a role of oral probiotics in the management of allergic diseases are emerging. Aim. We aimed at testing the immunomodulatory effects of intranasal versus intragastric administration of Lactobacillus paracasei NCC2461 in a mouse model of allergic airway inflammation and the specificity of different probiotics by comparing L. paracasei NCC2461 to Lactobacillus plantarum NCC1107. Methods. L. paracasei NCC2461 or L. plantarum NCC1107 strains were administered either intragastrically (NCC2461) or intranasally (NCC2461 or NCC1107) to OVA-sensitized mice challenged with OVA aerosols. Inflammatory cell recruitment into BALF, eotaxin and IL-5 production in the lungs were measured. Results. Intranasal L. paracasei NCC2461 efficiently protected sensitized mice upon exposure to OVA aerosols in a dose-dependent manner as compared to control mice. Inflammatory cell number, eotaxin and IL-5 were significantly reduced in BALF. Intranasal supplementation of L. paracasei NCC2461 was more potent than intragastric application in limiting the allergic response and possibly linked to an increase in T regulatory cells in the lungs. Finally, intranasal L. plantarum NCC1107 reduced total and eosinophilic lung inflammation, but increased neutrophilia and macrophages infiltration. Conclusion. A concerted selection of intervention schedule, doses, and administration routes (intranasal versus intragastric) may markedly contribute to modulate airway inflammation in a probiotic strain-specific manner.

Leukocytes, inflammation, and angiogenesis in cancer: fatal attractions.

Leukocytes are cells of defense. Their main function is to protect our body against invading microorganisms. Some leukocytes, in particular, polymorphonuclear and monocytes, accumulate at sites of infection and neutralize pathogens through innate mechanisms. The blood and lymphatic vascular system are essential partners in this defensive reaction: Activated endothelial cells promote leukocyte recruitment at inflammatory sites; new blood vessel formation, a process called angiogenesis, sustains chronic inflammation, and lymphatic vessels transport antigens and antigen-presenting cells to lymph nodes, where they stimulate naive T and B lymphocytes to elicit an antigen-specific immune response. In contrast, leukocytes and lymphocytes are far less efficient in protecting us from cancer, the "enemy from within." Worse, cancer can exploit inflammation to its advantage. The role of angiogenesis, leukocytes, and inflammation in tumor progression was discussed at the second Monte Verità Conference, Tumor Host Interaction and Angiogenesis: Basic Mechanisms and Therapeutic Perspectives, held in Ascona, Switzerland, October 1-5, 2005. (Conference chairs were K. Alitalo, M. Aguet, C. Rüegg, and I. Stamenkovic.) Eight articles reporting about topics presented at the conference are featured in this issue of the Journal of Leukocyte Biology.

Persisting atypical and cystic forms of Borrelia burgdorferi and local inflammation in Lyme neuroborreliosis

BACKGROUND: The long latent stage seen in syphilis, followed by chronic central nervous system infection and inflammation, can be explained by the persistence of atypical cystic and granular forms of Treponema pallidum. We investigated whether a similar situation may occur in Lyme neuroborreliosis. METHOD: Atypical forms of Borrelia burgdorferi spirochetes were induced exposing cultures of Borrelia burgdorferi (strains B31 and ADB1) to such unfavorable conditions as osmotic and heat shock, and exposure to the binding agents Thioflavin S and Congo red. We also analyzed whether these forms may be induced in vitro, following infection of primary chicken and rat neurons, as well as rat and human astrocytes. We further analyzed whether atypical forms similar to those induced in vitro may also occur in vivo, in brains of three patients with Lyme neuroborreliosis. We used immunohistochemical methods to detect evidence of neuroinflammation in the form of reactive microglia and astrocytes. RESULTS: Under these conditions we observed atypical cystic, rolled and granular forms of these spirochetes. We characterized these abnormal forms by histochemical, immunohistochemical, dark field and atomic force microscopy (AFM) methods. The atypical and cystic forms found in the brains of three patients with neuropathologically confirmed Lyme neuroborreliosis were identical to those induced in vitro. We also observed nuclear fragmentation of the infected astrocytes using the TUNEL method. Abundant HLA-DR positive microglia and GFAP positive reactive astrocytes were present in the cerebral cortex. CONCLUSION: The results indicate that atypical extra- and intracellular pleomorphic and cystic forms of Borrelia burgdorferi and local neuroinflammation occur in the brain in chronic Lyme neuroborreliosis. The persistence of these more resistant spirochete forms, and their intracellular location in neurons and glial cells, may explain the long latent stage and persistence of Borrelia infection. The results also suggest that Borrelia burgdorferi may induce cellular dysfunction and apoptosis. The detection and recognition of atypical, cystic and granular forms in infected tissues is essential for the diagnosis and the treatment as they can occur in the absence of the typical spiral Borrelia form.

Clostridium difficile toxin-induced inflammation and intestinal injury are mediated by the inflammasome.

BACKGROUND & AIMS: Clostridium difficile-associated disease (CDAD) is the leading cause of nosocomial diarrhea in the United States. C difficile toxins TcdA and TcdB breach the intestinal barrier and trigger mucosal inflammation and intestinal damage. The inflammasome is an intracellular danger sensor of the innate immune system. In the present study, we hypothesize that TcdA and TcdB trigger inflammasome-dependent interleukin (IL)-1beta production, which contributes to the pathogenesis of CDAD. METHODS: Macrophages exposed to TcdA and TcdB were assessed for IL-1beta production, an indication of inflammasome activation. Macrophages deficient in components of the inflammasome were also assessed. Truncated/mutated forms of TcdB were assessed for their ability to activate the inflammasome. The role of inflammasome signaling in vivo was assessed in ASC-deficient and IL-1 receptor antagonist-treated mice. RESULTS: TcdA and TcdB triggered inflammasome activation and IL-1beta secretion in macrophages and human mucosal biopsy specimens. Deletion of Nlrp3 decreased, whereas deletion of ASC completely abolished, toxin-induced IL-1beta release. TcdB-induced IL-1beta release required recognition of the full-length toxin but not its enzymatic function. In vivo, deletion of ASC significantly reduced toxin-induced inflammation and damage, an effect that was mimicked by pretreatment with the IL-1 receptor antagonist anakinra. CONCLUSIONS: TcdA and TcdB trigger IL-1beta release by activating an ASC-containing inflammasome, a response that contributes to toxin-induced inflammation and damage in vivo. Pretreating mice with the IL-1 receptor antagonist anakinra afforded the same level of protection that was observed in ASC-/- mice. These data suggest that targeting inflammasome or IL-1beta signaling may represent new therapeutic targets in the treatment of CDAD.

Poly (ADP-ribose) polymerase-1 is a key mediator of liver inflammation and fibrosis.

Poly (ADP-ribose) polymerase 1 (PARP-1) is a constitutive enzyme, the major isoform of the PARP family, which is involved in the regulation of DNA repair, cell death, metabolism, and inflammatory responses. Pharmacological inhibitors of PARP provide significant therapeutic benefits in various preclinical disease models associated with tissue injury and inflammation. However, our understanding the role of PARP activation in the pathophysiology of liver inflammation and fibrosis is limited. In this study we investigated the role of PARP-1 in liver inflammation and fibrosis using acute and chronic models of carbon tetrachloride (CCl4 )-induced liver injury and fibrosis, a model of bile duct ligation (BDL)-induced hepatic fibrosis in vivo, and isolated liver-derived cells ex vivo. Pharmacological inhibition of PARP with structurally distinct inhibitors or genetic deletion of PARP-1 markedly attenuated CCl4 -induced hepatocyte death, inflammation, and fibrosis. Interestingly, the chronic CCl4 -induced liver injury was also characterized by mitochondrial dysfunction and dysregulation of numerous genes involved in metabolism. Most of these pathological changes were attenuated by PARP inhibitors. PARP inhibition not only prevented CCl4 -induced chronic liver inflammation and fibrosis, but was also able to reverse these pathological processes. PARP inhibitors also attenuated the development of BDL-induced hepatic fibrosis in mice. In liver biopsies of subjects with alcoholic or hepatitis B-induced cirrhosis, increased nitrative stress and PARP activation was noted. CONCLUSION: The reactive oxygen/nitrogen species-PARP pathway plays a pathogenetic role in the development of liver inflammation, metabolism, and fibrosis. PARP inhibitors are currently in clinical trials for oncological indications, and the current results indicate that liver inflammation and liver fibrosis may be additional clinical indications where PARP inhibition may be of translational potential.

Evidence for chronic low-grade systemic inflammation in individuals with agoraphobia from a population-based prospective study.

BACKGROUND: Anxiety disorders have been linked to an increased risk of incident coronary heart disease in which inflammation plays a key pathogenic role. To date, no studies have looked at the association between proinflammatory markers and agoraphobia. METHODS: In a random Swiss population sample of 2890 persons (35-67 years, 53% women), we diagnosed a total of 124 individuals (4.3%) with agoraphobia using a validated semi-structured psychiatric interview. We also assessed socioeconomic status, traditional cardiovascular risk factors (i.e., body mass index, hypertension, blood glucose levels, total cholesterol/high-density lipoprotein-cholesterol ratio), and health behaviors (i.e., smoking, alcohol consumption, and physical activity), and other major psychiatric diseases (other anxiety disorders, major depressive disorder, drug dependence) which were treated as covariates in linear regression models. Circulating levels of inflammatory markers, statistically controlled for the baseline demographic and health-related measures, were determined at a mean follow-up of 5.5 ± 0.4 years (range 4.7 - 8.5). RESULTS: Individuals with agoraphobia had significantly higher follow-up levels of C-reactive protein (p = 0.007) and tumor-necrosis-factor-α (p = 0.042) as well as lower levels of the cardioprotective marker adiponectin (p = 0.032) than their non-agoraphobic counterparts. Follow-up levels of interleukin (IL)-1β and IL-6 did not significantly differ between the two groups. CONCLUSIONS: Our results suggest an increase in chronic low-grade inflammation in agoraphobia over time. Such a mechanism might link agoraphobia with an increased risk of atherosclerosis and coronary heart disease, and needs to be tested in longitudinal studies.

Symptômes, fonction respiratoires et inflammation bronchique liés à l'exposition professionnelle chronique aux brouillards d'huile entière : étude de faisabilité

Les fluides de coupe sont largement utilisés dans les industries mécaniques des machines-outils pour assurer la lubrification et le refroidissement des pièces métalliques. Lors de l'usinage, les machines-outils provoquent, de par leur grande vitesse de rotation, l'émission d'huile. On estime qu'environ 400'000 travailleurs sont exposés aux fluides de coupe en Suisse, plus de la moitié d'entre eux étant aux huiles entières (minérales ou synthétiques, non diluées avec de l'eau). Dans la littérature, on observe des effets respiratoires chroniques potentiellement précurseurs d'une bronchite et/ou de broncho-pneumopathie chronique obstructive chez des travailleurs exposés de manière chronique aux brouillards d'huile entière. Le problème est que le lien entre le retentissement respiratoire chronique et le niveau d'exposition professionnel des travailleurs exposés aux brouillards d'huile est difficile à mettre en évidence, car la mesure de l'exposition aux brouillards d'huile était jusqu'à présent très imprécise. Une nouvelle technique permettant de mesurer les deux fractions (particulaire et volatile) des brouillards d'huile entière vient d'être validée. L'objectif principal de l'étude est d'évaluer la faisabilité d'une étude de cohorte prospective à large échelle sur le lien entre l'exposition professionnelle chronique aux brouillards d'huile entière , mesurée de manière plus précise selon cette nouvelle technique, et les symptômes, la fonction respiratoire et l'inflammation bronchique. L'objectif secondaire est d'étudier le lien entre l'exposition professionnelle aiguë aux brouillards d'huile entière parmi ces travailleurs (n=14) et les symptômes, la fonction respiratoire et l'inflammation bronchique. Il s'agit d'une étude épidémiologique d'observation de type transversale. Les sujets étudiés sont des salariés de l'industrie du décolletage. La faisabilité a été déterminée sur la base de critères portant sur le recrutement, la récolte des données et l'analyse des données. La récolte de données a eu lieu après 48h de non-exposition, à l'aide d'un questionnaire d'exposition au poste de travail, un curriculum laboris et questionnaire des symptômes, la mesure du NO exhalé, une spirométrie et la mesure individuelle et sur postes fixes des expositions actuelles aux brouillards d'huile entière par la nouvelle méthode. Les difficultés et les points positifs rencontrés ont permis d'émettre des recommandations en vue de la réalisation une étude à plus large échelle. Aucun lien n'a pu être démontré au vu du faible nombre de travailleurs inclus et les niveaux relativement bas d'exposition aux brouillards d'huile entière mesurés. Sur la base de l'étude de faisabilité, une étude de cohorte prospective est recommandée pour établir un lien entre le niveau de brouillards d'huile entière et les effets respiratoires.

Fluorine MR Imaging of Inflammation in Atherosclerotic Plaque in Vivo.

PURPOSE: To preliminarily test the hypothesis that fluorine 19 ((19)F) magnetic resonance (MR) imaging enables the noninvasive in vivo identification of plaque inflammation in a mouse model of atherosclerosis, with histologic findings as the reference standard. MATERIALS AND METHODS: The animal studies were approved by the local animal ethics committee. Perfluorocarbon (PFC) emulsions were injected intravenously in a mouse model of atherosclerosis (n = 13), after which (19)F and anatomic MR imaging were performed at the level of the thoracic aorta and its branches at 9.4 T. Four of these animals were imaged repeatedly (at 2-14 days) to determine the optimal detection time. Repeated-measures analysis of variance with a Tukey test was applied to determine if there was a significant change in (19)F signal-to-noise ratio (SNR) of the plaques and liver between the time points. Six animals were injected with a PFC emulsion that also contained a fluorophore. As a control against false-positive results, wild-type mice (n = 3) were injected with a PFC emulsion, and atherosclerotic mice were injected with a saline solution (n = 2). The animals were sacrificed after the last MR imaging examination, after which high-spatial-resolution ex vivo MR imaging and bright-field and immunofluorescent histologic examination were performed. RESULTS: (19)F MR signal was detected in vivo in plaques in the aortic arch and its branches. The SNR was found to significantly increase up to day 6 (P < .001), and the SNR of all mice at this time point was 13.4 ± 3.3. The presence of PFC and plaque in the excised vessels was then confirmed both through ex vivo (19)F MR imaging and histologic examination, while no signal was detected in the control animals. Immunofluorescent histologic findings confirmed the presence of PFC in plaque macrophages. CONCLUSION: (19)F MR imaging allows the noninvasive in vivo detection of inflammation in atherosclerotic plaques in a mouse model of atherosclerosis and opens up new avenues for both the early detection of vulnerable atherosclerosis and the elucidation of inflammation mechanisms in atherosclerosis.

Toll-like receptor 5 deficiency exacerbates cardiac injury and inflammation induced by myocardial ischaemia-reperfusion in the mouse.

Myocardial ischaemia-reperfusion (MIR) triggers a sterile inflammatory response important for myocardial healing, but which may also contribute to adverse ventricular remodelling. Such inflammation is initiated by molecular danger signals released by damaged myocardium, which induce innate immune responses by activating toll-like receptors (TLRs). Detrimental roles have been recently reported for TLR2, TLR3 and TLR4. The role of other TLRs is unknown. We therefore evaluated the role of TLR5, expressed at high level in the heart, in the development of myocardial damage and inflammation acutely triggered by MIR. TLR5-/- and wild-type (WT) mice were exposed to MIR (30 min ischaemia, 2 h reperfusion). We measured infarct size, markers of cardiac oxidative stress, myocardial phosphorylation state of mitogen-activated protein (MAP) kinases and AKT, expression levels of chemokines and cytokines in the heart and plasma, as well as cardiac function by echography and conductance volumetry. TLR5-deficient mice had normal cardiac morphology and function under physiological conditions. After MIR, the absence of TLR5 promoted an increase in infarct size and myocardial oxidative stress. Lack of TLR5 fostered p38 phosphorylation, reduced AKT phosphorylation and markedly increased the expression of inflammatory cytokines, whereas it precipitated acute LV (left ventricle) dysfunction. Therefore, contrary to the detrimental roles of TLR2, TLR3 and TLR4 in the infarcted heart, TLR5 is important to limit myocardial damage, inflammation and functional compromise after MIR.

T cells at the site of autoimmune inflammation show increased potential for trogocytosis

Les lymphocytes T CD4+ sont connus pour leur potentiel d'acquisition de fragments membraneux de cellules présentatrices d'antigène (CPA) dans un processus nommé trogocytose. Ce phénomène est observé lors de l'interaction entre le lymphocyte T CD4+ antigène-spécifique et la CPA lors de la présentation de l'antigène en question, et dépend donc de la spécificité du lymphocyte T CD4+. L'identification des lymphocytes T CD4+ sujets à la trogocytose en co-culture avec des CPA chargées d'un antigène connu permet d'enrichir des lymphocytes T antigène-spécifiques sans connaître leur spécificité exacte ou leur profil de production de cytokines. Dans cette étude, nous avons donc cherché à évaluer l'utilité de cette méthode dans l'identification de la spécificité des lymphocytes T effecteurs et régulateurs lors de l'inflammation auto-immune avec des spécificités souvent inconnues. La trogocytose a démontré son efficacité dans la détection de lymphocytes T réactifs à la protéine basique de myéline in vitro ainsi qu'ex vivo après immunisation. Cependant, le potentiel de la trogocytose à identifier des lymphocytes T régulateurs antigène-spécifiques est limité par le fait que les lymphocytes T régulateurs Foxp3+ montrent un taux élevé de manière constitutive de trogocytose comparé aux lymphocytes T Foxp3-, Un taux localement élevé de trogocytose lors d'un état inflammatoire (observé au niveau des lymphocytes T effecteurs et régulateurs isolés du système nerveux central enflammé) empêche l'utilisation de la trogocytose dans l'évaluation de la réactivité antigénique de cellules extraites d'un site inflammatoire. Nos résultats montrent la possibilité d'enrichir des lymphocytes T conventionnels antigène- réactifs en périphérie par détection au moyen de la trogocytose. Nous avons aussi montré les limitations de cette méthode dans sa capacité d'identifier des lymphocytes T effecteurs et régulateurs antigène- réactifs extraits de sites inflammatoires. Le potentiel de trogocytose élevé dans les sites d'inflammation soulève la question de la signification biologique de ce phénomène dans l'inflammation, dans la suppression médiée par les lymphocytes T régulateurs et dans le maintien de la tolérance immunologique dans des états de santé variables.