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10 result(s) for "van de Veerdonk, F.L."
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Influenza virus and factors that are associated with ICU admission, pulmonary co-infections and ICU mortality
While most influenza patients have a self-limited respiratory illness, 5–10% of hospitalized patients develop severe disease requiring ICU admission. The aim of this study was to identify influenza-specific factors associated with ICU admission and mortality. Furthermore, influenza-specific pulmonary bacterial, fungal and viral co-infections were investigated. 199 influenza patients, admitted to two academic hospitals in the Netherlands between 01-10-2015 and 01-04-2016 were investigated of which 45/199 were admitted to the ICU. A history of Obstructive/Central Sleep Apnea Syndrome, myocardial infarction, dyspnea, influenza type A, BMI > 30, the development of renal failure and bacterial and fungal co-infections, were observed more frequently in patients who were admitted to the ICU, compared with patients at the normal ward. Co-infections were evident in 55.6% of ICU-admitted patients, compared with 20.1% of patients at the normal ward, mainly caused by Staphylococcus aureus, Streptococcus pneumoniae, and Aspergillus fumigatus. Non-survivors suffered from diabetes mellitus and (pre-existent) renal failure more often. The current study indicates that a history of OSAS/CSAS, myocardial infarction and BMI > 30 might be related to ICU admission in influenza patients. Second, ICU patients develop more pulmonary co-infections. Last, (pre-existent) renal failure and diabetes mellitus are more often observed in non-survivors. •A history of OSAS/CSAS, myocardial infarction and BMI > 30 are risk factors for ICU admission.•Non-survivors suffer more often from diabetes mellitus and (pre-existent) renal failure.•ICU patients develop renal failure and bacterial/fungal co-infections more often.
Inflammasome is a central player in the induction of obesity and insulin resistance
Inflammation plays a key role in the pathogenesis of obesity. Chronic overfeeding leads to macrophage infiltration in the adipose tissue, resulting in proinflammatory cytokine production. Both microbial and endogenous danger signals trigger assembly of the intracellular innate immune sensor Nlrp3, resulting in caspase-1 activation and production of proinflammatory cytokines IL-1β and IL-18. Here, we showed that mice deficient in Nlrp3, apoptosis-associated speck-like protein, and caspase-1 were resistant to the development of high-fat diet-induced obesity, which correlated with protection from obesity-induced insulin resistance. Furthermore, hepatic triglyceride content, adipocyte size, and macrophage infiltration in adipose tissue were all reduced in mice deficient in inflammasome components. Monocyte chemoattractant protein (MCP)-1 is a key molecule that mediates macrophage infiltration. Indeed, defective inflammasome activation was associated with reduced MCP-1 production in adipose tissue. Furthermore, plasma leptin and resistin that affect energy use and insulin sensitivity were also changed by inflammasome-deficiency. Detailed metabolic and molecular phenotyping demonstrated that the inflammasome controls energy expenditure and adipogenic gene expression during chronic overfeeding. These findings reveal a critical function of the inflammasome in obesity and insulin resistance, and suggest inhibition of the inflammasome as a potential therapeutic strategy.
STAT1 Mutations in Autosomal Dominant Chronic Mucocutaneous Candidiasis
Autosomal dominant chronic mucocutaneous candidiasis (CMC) is a severe immunodeficiency characterized by mucosal infections with fungi. Mutations affecting a particular region of the STAT1 signaling protein cause autosomal dominant CMC, probably through denting of the responses of type 1 and type 17 helper T cells. Chronic mucocutaneous candidiasis (CMC) is a primary immunodeficiency disorder that is characterized by susceptibility to infection of the skin, nails, and mucous membranes by candida species and dermatophytes. 1 There are several CMC subtypes: autosomal recessive autoimmune polyendocrinopathy candidiasis with ectodermal dystrophy (APECED), autosomal dominant CMC with or without thyroid disease, and autosomal recessive, isolated CMC. The defect in APECED resides in the autoimmune regulator AIRE, which has a key role in immunotolerance. 2 The susceptibility to candida in patients with APECED is attributed to autoantibodies to interleukin-17 and interleukin-22, 3 since type 17 helper T cells (Th17) are crucial for mucosal antifungal . . .
IL-38 binds to the IL-36 receptor and has biological effects on immune cells similar to IL-36 receptor antagonist
The functional role of IL-1 family member 10, recently renamed IL-38, remains unknown. In the present study we aimed to elucidate the biological function of IL-38 and to identify its receptor. Heatkilled Candida albicans was used to stimulate memory T-lymphocyte cytokine production in freshly obtained human peripheral blood mononuclear cells from healthy subjects. The addition of recombinant IL-38 (152 amino acids) inhibited the production of T-cell cytokines IL-22 (37% decrease) and IL-17 (39% decrease). The reduction in IL-22 and IL-17 caused by IL-38 was similar to that caused by the naturally occurring IL-36 receptor antagonist (IL-36Ra) in the same peripheral blood mononuclear cells cultures. IL-8 production induced by IL-36y was reduced by IL-38 (42% decrease) and also was reduced by IL-36Ra (73% decrease). When human blood monocyte-derived dendritic cells were used, IL-38 as well as IL-36Ra increased LPS-induced IL-6 by twofold. We screened immobilized extracellular domains of each member of the IL-1 receptor family, including the immobilized extracellular domains of each member of the IL-1 receptor family, including the IL-36 receptor (also known as \"IL-1 receptor-related protein 2\") and observed that IL-38 bound only to the IL-36 receptor, as did IL-36Ra. The dose-response suppression of IL-38 as well as that of IL-36Ra of Candida-induced IL-22 and IL-17 was not that of the classic IL-1 receptor antagonist (anakinra), because low concentrations were optimal for inhibiting IL-22 production, whereas higher concentrations modestly increased IL-22. These data provide evidence that IL-38 binds to the IL-36R, as does IL-36Ra, and that IL-38 and IL-36Ra have similar biological effects on immune cells by engaging the IL-36 receptor.
In-host adaptation and acquired triazole resistance in Aspergillus fumigatus: a dilemma for clinical management
Aspergillus fumigatus causes a range of diseases in human beings, some of which are characterised by fungal persistence. A fumigatus can persist by adapting to the human lung environment through physiological and genomic changes. The physiological changes are based on the large biochemical versatility of the fungus, and the genomic changes are based on the capacity of the fungus to generate genetic diversity by spontaneous mutations or recombination and subsequent selection of the genotypes that are most adapted to the new environment. In this Review, we explore the adaptation strategies of A fumigatus in relation to azole resistance selection and the clinical implications thereof for management of diseases caused by Aspergillus spp. We hypothesise that the current diagnostic tools and treatment strategies do not take into account the biology of the fungus and might result in an increased likelihood of fungal persistence in patients. Stress factors, such as triazole exposure, cause mutations that render resistance. The process of reproduction—ie, sexual, parasexual, or asexual—is probably crucial for the adaptive potential of Aspergillus spp. As any change in the environment can provoke adaptation, switching between triazoles in patients with chronic pulmonary aspergillosis might result in a high-level pan-triazole-resistant phenotype through the accumulation of resistance mutations. Alternatively, when triazole therapy is stopped, an azole-free environment is created that could prompt selection for compensatory mutations that overcome any fitness costs that are expected to accompany resistance development. As a consequence, starting, switching, and stopping azole therapy has the risk of selecting for highly resistant strains with wildtype fitness. A similar adaptation is expected to occur in response to other stress factors, such as endogenous antimicrobial peptides; over time the fungus will become increasingly adapted to the lung environment, thereby limiting the probability of eradication. Our hypothesis challenges current management strategies, and future research should investigate the genomic dynamics during infection to understand the key factors facilitating adaptation of Aspergillus spp.
Reactive oxygen species-independent activation of the IL-1β inflammasome in cells from patients with chronic granulomatous disease
Humans with chronic granulomatous diseases (CGDs) due to mutations in p47-phox have defective NADPH activity and thus cannot generate NADPH-dependent reactive oxygen species (ROS). The role of ROS in inflammation is controversial; some in vitro studies suggest that ROS are crucial for secretion of IL-1β via inflammasome activation, whereas mice defective for ROS and patients with CGD have a proinflammatory phenotype. In this study, we evaluated activation of the IL-1β inflammasome in cells from CGD patients. In contrast to previous studies using the small molecule diphenylene iodonium (DPI) as a ROS inhibitor, we found no decrease in either caspase-1 activation or secretion of IL-1β and IL-18 in primary CGD monocytes. Moreover, activation of CGD monocytes by uric acid crystals induced a 4-fold higher level of IL-1β secretion compared with that seen in monocytes from unaffected subjects, and this increase was not due to increased synthesis of the IL-1β precursor. In addition, Western blot analysis of CGD cells revealed that caspase-1 activation was not decreased, but rather was increased compared with control cells. Examination of the effects exerted by the inhibition of ROS activity by DPI revealed that the decrease in IL-1β secretion by DPI was actually due to inhibition of IL-1β gene expression. Thus, inconsistent with the proinflammatory role of ROS, the present findings support the concept that ROS likely dampen inflammasome activation. The absence of ROS in CGD monocytes may explain the presence of an inflammatory phenotype characterized by granulomas and inflammatory bowel disease occurring in CGD patients.
Crohn's disease-associated ATG16L1 polymorphism modulates pro-inflammatory cytokine responses selectively upon activation of NOD2
ObjectiveAutophagy has recently been shown to modulate the production of pro-inflammatory cytokine production and to contribute to antigen processing and presentation through the major histocompatibility complex. Genetic variation in the autophagy gene ATG16L1 has been recently implicated in Crohn's disease pathogenesis. The mechanisms underlying this association are not yet known, although experimental models suggest an inhibitory effect of autophagy on interleukin 1β (IL-1β) responses. Here, the effect of ATG16L1 genetic variation on cytokine responses has been assessed in humans.Design and settingPeripheral blood mononuclear cells from healthy individuals and patients with Crohn's disease with different ATG16L1 genotypes were stimulated with ligands for Toll-like receptor 2 (TLR2), TLR4 and nucleotide-binding oligomerisation domain 2 (NOD2), with or without the autophagy inhibitor 3-methyladenine. Induction of cytokine production and related factors were measured at the mRNA and protein level. Furthermore, protein levels of ATG16L1 were assessed by western blot.ResultsThe present study demonstrates that cells isolated from individuals bearing the ATG16L1 Thr300Ala risk variant, which is shown to affect ATG16L1 protein expression upon NOD2 stimulation, display increased production of the pro-inflammatory cytokines IL-1β and IL-6, specifically after stimulation with NOD2 ligands. In contrast, no differences were found when cells were stimulated with TLR2 or TLR4 agonists. These findings were confirmed in two independent cohorts of volunteers and in a group of patients with Crohn's disease. The increased production could be ascribed to increased mRNA expression, while processing of pro-IL-1β by caspase-1 activation was not affected. The effect of the ATG16L1 polymorphism was abrogated when autophagy was blocked.ConclusionsThe present study is the first to link the ATG16L1 polymorphism with an excessive production of IL-1β and IL-6 in humans, which may explain the effects of this polymorphism on the inflammatory process in Crohn's disease.
OP0170 Human il-38 reduces joint inflammation in a mouse model of gouty arthritis
BackgroundInterleukin-38 (IL-38) is the last member of the IL-1 family of cytokines to be fully investigated for its functions. IL-38 is proposed as an anti-inflammatory cytokine in various auto-inflammatory diseases, such as psoriasis and rheumatoid arthritis. For example, IL-38 knockout mice have exacerbated autoantibody-induced arthritis. Current understanding of the capacity of IL-38 in gout, a prototype IL-1β driven auto-inflammatory disease, is unknown.ObjectivesWe hypothesised that in vivo treatment with human recombinant IL-38 results in a reduction in join inflammation in a mouse model of gouty arthritis.MethodsWe treated C57/Bl6 mice with 1 µg recombinant IL-38 (3–152 AA) intraperitoneally at 24, 12 and 2 hours before induction of gouty arthritis with intra-articular injection of albumin-opsonized monosodium urate crystals (300 µg) and palmitic acid (200 µM) in 10 µL PBS. Joint inflammation was scored after 4 hours. The synovial lining was cultured in RPMI for 2 hours to allow cytokines to be secreted, and cytokines in the synovium were extracted with Triton-X 100 to obtain total cytokines (membrane and intracellular). In the synovial culture fluid and extract, IL-1β, IL-6 and KC were measured by ELISA. DataResultsMice treated with recombinant IL-38 exhibited significantly reduced joint swelling and redness on a three-point macroscopic inflammation scale: Vehicle-treated 1.5±0.25 vs IL-38 Treated 0.75+0.25 (n=10, p<0.0001, Mann Whitney-U test). The 2 hour synovial membrane culture fluid contained significantly lower levels of IL–1β (1207±480 vs 379±184 pg/mL, p<0.05), IL-6 (10783±2490 vs 5321±2935 pg/mL, p<0.05) and KC (4390±931 vs 1081±750 pg/mL, p<0.05). In extract of the synovial membrane, there is a reduction in IL–1β (1505±397 vs 624±509 pg/mL, p<0.05), IL-6 (11059±2299 vs 3597±2509 pg/mL, p<0.01) and KC (1505±397 vs 624±509 pg/mL, p<0.05).ConclusionsHuman recombinant IL-38 reduces swelling and redness of the joint, and pro-inflammatory cytokines secreted by and contained in the synovial membrane in a mouse model of gouty arthritis. These data reveal that recombinant IL-38 has therapeutic benefit in an IL–1β mediated model of inflammation.Disclosure of InterestNone declared
Bypassing Pathogen-Induced Inflammasome Activation for the Regulation of Interleukin-1β Production by the Fungal Pathogen Candida albicans
BackgroundInterleukin (IL)–1β has an important role in antifungal defense mechanisms. The inflammasome is thought to be required for caspase-1 activation and processing of the inactive precursor pro-IL-1β. The aim of the present study was to investigate the pathways of IL-1β production induced by Candida albicans in human monocytes MethodsHuman mononuclear cells were stimulated with C. albicans or mutant strains defective in mannosylation or chitin. Receptors were blocked with specific antagonists, and the IL-1β concentration was measured ResultsHuman primary monocytes produce bioactive IL-1β when stimulated with C. albicans. The transcription of IL-1β was induced through mannose receptor (MR), Toll-like receptor (TLR) 2, and dectin-1 but not through TLR4 and TLR9. N-mannan–linked residues, chitin, and β-glucan from C. albicans are important for IL-1β stimulation. Surprisingly, processing and secretion of IL-1β in monocytes did not require pathogen-mediated inflammasome activation, because of the constitutive activation of caspase-1 and the capability of monocytes to release endogenous adenosine-5′-triphosphate ConclusionsThis study is the first dissection of the molecular mechanisms of IL-1β production by a fungal pathogen. Transcription through mannan/chitin/MR and β-glucan/dectin-1/TLR2 induces production of IL-1β by C. albicans in human monocytes, whereas processing of IL-1β is mediated by constitutively active caspase-1