TNF-α Antagonism Research Articles

POS0409 MOLECULAR PROFILING OF THE REMISSION STATE IN PSORIATIC ARTHRITIS: IS THE FIRE EXTINGUISHED?

Background:The most important goal of therapy in psoriatic arthritis (PsA) is to reach the remission state of disease. Nowadays, data on molecular players of clinical remission and effective disease inactivation are scarce: gene expression analysis could highlight markers characteristic of PsA remission state.Objectives:Our aim was to analyze the gene expression profile of patients with clinically inactive (drug-induced remission) PsA versus healthy controls and PsA active state.Methods:From a cohort of 300 patients affected by PsA according to CASPAR criteria, we selected 40 patients (peripheral arthritis subset) with >1-year remission by TNFα antagonism assessed by DAPSA ≤ 4 (R) and 40 PsA with active disease state by DAPSA > 14 score (no bDMARDs ongoing) (A), and 40 healthy controls (HC) matching for mean age and gender ratio. Both PsA groups were not on corticosteroid treatment. Each condition has been profiled first using pooled RNAs from peripheral blood (biological duplicates) by Affymetrix Human GeneChip HTA 2.0. To identify a transcript as differentially expressed in both duplicates, a fold change (FC) 1.5 and p-value 0.05 has been set. Then, from the comparative list of differential expressed genes (DEGs) in R vs HC state, coding mRNAs were selected and interactions analyzed by STRING software, biological functions and annotations by Gene Onthology (GO). From these analysis, 12 genes were validated in the whole PsA cohort (R+A) and HCs, by quantitative real-time PCR (RT-qPCR) in triplicate (TaqMan chemistry, GAPDH housekeeping, 2–ΔΔCt for relative quantification, FC cutoff ±1.5 for differential analysis).Results:The transcriptomic analysis generated 3 comparative lists of mRNAs (R vs HC= 125; R vs A= 1184; A vs HC= 378 transcripts). Then, we focused on remission state analyzing the mRNAs list R vs HC. Filtering data for coding DEGs, was made a list of 24 genes further analyzed for functions and interactions: STRING analysis created one interactions network and GO highlighted in which biological processes these DEGs are involved (Fig panels 1A, 1B). Validation analysis by rt-qPCR in the PsA cohort (R+A) and HCs confirmed the downregulation of c-FOS and the upregulation of CCDC50 (alias YMER) genes in the R vs HC conditions (pvalue= 0.004). The dysregulation of further genes in other comparisons was measured, as shown in Tab and Fig panel 1C.Conclusion:Observing the amount of DEGs, is evident that the drug-induced remission state is more similar to healthy condition, however this trend of “similarity” does not mean “identical”. The bioinformatic analysis showed that DEGs in the R vs HC conditions are primarily involved in biological processes related to immune system as well as correlates in an interactions network. Our molecular characterization of clinical remission revealed that effective disease inactivation appears to be molecularly-driven by two key genes, c-FOS and CCD50 (YMER), both involved in the NF-κB signalling pathway modulation.Coding DEGs mis-regulated in the remission state. Differentially expressed genes (DEGs) in the Remission (R) state vs Healthy Controls (HC) analyzed for multiple-proteins interaction by STRING software V10.5 (panel A) and biological functions by Gene Set Enrichment Analysis (panel B). DEGs validations by RT-qPCR, confirmed the CCD50 and c-FOS dysregulation in the R state (panel C, RQ= Relative Quantification, t test RvsHC pvalue=0,004).GENE SYMBOLGene chip Array R vs HCRemission vs HCActive vs HCRemission vs ActiveALPL-1.7-1.11.3-1.25ANPEP-1.681.01.1-1.1BPI-1.57-1.11.27-1.5CCDC501.51.5-1.251.8CEACAM8-2.3-1.21.2-1.5CHI3L1-1.59-1.1-1.0-1.0DEFA1B-2.3-1.41.9-2.7FCAR-1.56-1.11.1-1.3FOS-1.51-2.0-1.5-1.4KLRB11.52-1-1.61.6PADI2-1.54-1.11.0-1.1TNFSF14-1.511.11.2-1.1DEGs by RT-qPCR. Validated differentially expressed genes (DEGs) in the remission (R) state vs healthy controls (HC) selected from the microarray analysis comparative list (FC cutoff ±1.5). Differential analysis (40 R vs 40 HC vs 40 Active) was made by FoldChange (FC) cutoff ±1.5 (overexpressed ≥ 1.5; - 1.5 ≥ downregulated).Disclosure of Interests:None declared

Tumor Necrosis Factor Alpha: Role in the Development of Obesity and Diabetes Mellitus

Obesity and Diabetes Mellitus (DM) are defined as worldwide pandemics by the World health organization due to their economic burden and widespread. Although a huge amount of research is being done in the field of obesity and DM today, many questions remain unsolved. Tissue inflammation is the main factor in the development of both obesity and DM, leading towards irreversible changes in the tissue and formation of specific complications. One of the widespread cytokines, tumor necrosis factor alpha (TNF-α), was shown to be involved with inflammation in the development of metabolic disorders and neurodegenerative diseases. Even though the role of TNF-α in the pathogenesis of these two diseases remains unclear, new ways of treating and preventing diseases based on TNF-α antagonism attracted the attention of scientists. In this review, TNF-α and its receptors’ structures and properties are explored, and their role in disease development, including obesity and type 2 DM (DM2) will be discussed by viewing data from literature.

TNF-α antagonism with etanercept enhances penile NOS expression, cavernosal reactivity, and testosterone levels in aged rats.

Erectile dysfunction (ED) has been reported to be associated with inflammation. This study investigated the effects of tumor necrosis factor alpha (TNF-α) inhibitor etanercept on penile neuronal nitric oxide synthase (nNOS) and endothelial nitric oxide synthase (eNOS) expressions, testosterone concentrations, neurogenic and endothelium-dependent relaxations of corpus cavernosum (CC), and circulating and cavernosal levels of inflammatory markers in aged rats. Animals were separated into control, aged, and etanercept-treated aged groups. Aged rats displayed significantly increased serum and cavernosal TNF-α, C-reactive protein (CRP), monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule (ICAM-1) levels, and decreased penile nNOS and eNOS expressions and serum testosterone levels compared with controls. In etanercept-treated aged group, NOS expressions were similar to that of the control group. The circulating and cavernosal concentrations of TNF-α, CRP, MCP-1, ICAM-1, and testosterone were also normalized by etanercept. Neurogenic and endothelium-dependent relaxant responses significantly decreased in aged rats and etanercept treatment markedly improved these relaxation responses. Our findings indicate that aging decreases penile NOS expression, neurogenic and endothelium-dependent relaxations of CC, and also suppresses serum testosterone levels by inducing inflammatory response that may contribute to the development of ED. TNF-α antagonism may be a novel strategy to treat aging-associated ED.

Tumor necrosis factor-α, kidney function, and hypertension.

Hypertension is considered to be a low-grade inflammatory condition characterized by the presence of various proinflammatory cytokines. Tumor necrosis factor-α (TNF-α) is a constituent of the proinflammatory cytokines that is associated with salt-sensitive hypertension (SSH) and related renal injury. Elevated angiotensin II (ANG II) and other factors such as oxidative stress conditions promote TNF-α formation. Many recent studies have provided evidence that TNF-α exerts a direct renal action by regulating hemodynamic and excretory function in the kidney. The cytokine incites a strong natriuretic response and plays a part in regulation of the intrarenal renin-angiotensin system. The exact mechanistic role of TNF-α in the development of SSH is as yet poorly understood. While TNF-α antagonism has been shown to attenuate hypertensive responses in many hypertensive animal models, contrasting findings demonstrate that the direct systemic administration of TNF-α usually induces hypotensive as well as natriuretic responses, indicating a counterregulatory role of TNF-α in SSH. Differential activities of two cell surface receptors of TNF-α (receptor type 1 and type 2) may explain the contradictory functions of TNF-α in the setting of hypertension. This short review will evaluate ongoing research studies that investigate the action of TNF-α within the kidney and its role as an influential pathophysiological variable in the development of SSH and renal injury. This information may help to develop specific TNF-α receptor targeting as an effective treatment strategy in this clinical condition.

Autopsy-proven demyelination associated with infliximab treatment.

Tumor necrosis factor–α (TNF-α) is a well-studied proinflammatory cytokine that contributes to the pathogenesis of immune and infectious diseases. TNF-α effects are mediated by signaling through TNF-α receptors, which are present ubiquitously.1 Limiting the actions of TNF-α, either by blocking the receptor or inhibiting circulating (free) TNF-α, is a useful treatment strategy in autoimmune disorders with prominent inflammation, such as inflammatory bowel disease and rheumatoid arthritis (RA). However, when treatment with agents that inhibit TNF-α function was applied to multiple sclerosis (MS), an unanticipated worsening was observed. The clinical trial of lenercept (a recombinant TNF-α receptor–immunoglobulin 1g fusion protein that protected against experimental autoimmune encephalitis) for the treatment of relapsing-remitting multiple sclerosis was stopped prematurely when the treatment arm was noted to have earlier and more frequent exacerbations.2 TNF-α antagonists are therefore contraindicated in patients with MS. In patients with no history of demyelinating disease, TNF-α antagonism has led to unmasking of demyelinating events with a clinical pattern typical of that seen in MS.3 All CNS cases of demyelinating disease to date have been based on clinical, laboratory, and radiographic findings. Herein we present a unique case of histologically confirmed demyelination following treatment with TNFα inhibitors.

TNF-α antagonism ameliorates myocardial ischemia-reperfusion injury in mice by upregulating adiponectin.

Tumor necrosis factor-α (TNF-α) antagonism alleviates myocardial ischemia-reperfusion (MI/R) injury. However, the mechanisms by which the downstream mediators of TNF-α change after acute antagonism during MI/R remain unclear. Adiponectin (APN) exerts anti-ischemic effects, but it is downregulated during MI/R. This study was conducted to investigate whether TNF-α is responsible for the decrease of APN, and whether antagonizing TNF-α affects MI/R injury by increasing APN. Male adult wild-type (WT), APN knockout (APN KO) mice, and those with cardiac knockdowns of APN receptors via siRNA injection were subjected to 30 min of MI followed by reperfusion. The TNF-α antagonist etanercept or globular domain of APN (gAD) was injected 10 min before reperfusion. Etanercept ameliorated MI/R injury in WT mice as evidenced by improved cardiac function, and reduced infarct size and cardiomyocyte apoptosis. APN concentrations were augmented in response to etanercept, followed by an increase in AMP-activated protein kinase phosphorylation. Etanercept still increased cardiac function and reduced infarct size and apoptosis in both APN KO and APN receptors knockdown mice. However, its potential was significantly weakened in these mice compared with the WT mice. TNF-α is responsible for the decrease in APN during MI/R. The cardioprotective effects of TNF-α neutralization are partially due to the upregulation of APN. The results provide more insight into the TNF-α-mediated signaling effects during MI/R and support the need for clinical trials to validate the efficacy of acute TNF-α antagonism in the treatment of MI/R injury.

Infliximab improves endothelial dysfunction in a mouse model of antiphospholipid syndrome: Role of reduced oxidative stress

Antiphospholipid syndrome (APS), induces endothelial dysfunction, oxidative stress and systemic inflammation that may be mediated by TNFα. Thus, we investigated the possible protective effect of the anti-TNFα antibody infliximab (5μg/g) on endothelial function in a mouse APS model (induced by injection of purified human anti-β2GP1-IgG).Seven days after anti-β2GPI-IgG injection, we observed an increase in plasma sVCAM-1 and sE-selectin levels and in aortic mRNA expression of VCAM-1 and E-selectin. This was associated with a decreased endothelium-dependent relaxation of isolated mesenteric arteries to acetylcholine, together with decreased mesenteric eNOS mRNA expression and increased eNOS uncoupling, accompanied by increased iNOS and gp91phox mRNA and increased left ventricular GSH/GSSH ratio. Infliximab significantly improved the NO-mediated relaxing responses to acetylcholine, and induced a decrease in iNOS and gp91phox mRNA expression. The õpro-adhesive and pro-coagulant phenotypes induced by the anti-β2GP1-IgG were also reversed.This study provides the first evidence that TNFα antagonism improves endothelial dysfunction in APS and suggests that endothelial dysfunction is mediated by TNFα and oxidative stress. Therefore, infliximab may be of special relevance in clinical practice.

Etanercept blocks inflammatory responses orchestrated by TNF-α to promote transplanted cell engraftment and proliferation in rat liver

Engraftment of transplanted cells is critical for liver-directed cell therapy, but most transplanted cells are rapidly cleared from liver sinusoids by proinflammatory cytokines/chemokines/receptors after activation of neutrophils or Kupffer cells (KCs). To define whether tumor necrosis factor alpha (TNF-α) served roles in cell-transplantation-induced hepatic inflammation, we used the TNF-α antagonist, etanercept (ETN), for studies in syngeneic rat hepatocyte transplantation systems. After cell transplantation, multiple cytokines/chemokines/receptors were overexpressed, whereas ETN before cell transplantation essentially normalized these responses. Moreover, ETN down-regulated cell-transplantation-induced intrahepatic release of secretory cytokines, such as high-mobility group box 1. These effects of ETN decreased cell-transplantation-induced activation of neutrophils, but not of KCs. Transplanted cell engraftment improved by several-fold in ETN-treated animals. These gains in cell engraftment were repeatedly realized after pretreatment of animals with ETN before multiple cell transplantation sessions. Transplanted cell numbers did not change over time, indicating absence of cell proliferation after ETN alone. By contrast, in animals preconditioned with retrorsine and partial hepatectomy, cell transplantation after ETN pretreatment significantly accelerated liver repopulation, compared to control rats. TNF-α plays a major role in orchestrating cell-transplantation-induced inflammation through regulation of multiple cytokines/chemokines/receptor expression. Because TNF-α antagonism by ETN decreased transplanted cell clearance, improved cell engraftment, and accelerated liver repopulation, this pharmacological approach to control hepatic inflammation will help optimize clinical strategies for liver cell therapy.

Preventive and remedial application of etanercept attenuate monocrotaline‐induced pulmonary arterial hypertension

To evaluate the efficacy of etanercept (ETN) on monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH) in rats. A PAH rat model was induced by intraperitoneal injection (i.p.) of MCT (60 mg/kg) once and ENT therapy (2.5 mg/kg twice a week i.p.) was initiated on the day following MCT injection (prevention protocol) or after PAH is established (remedial protocol) for 2 weeks. The mean pulmonary arterial pressure (mPAP) was measured using a right heart catheterization technique; quantitative determination of lung small artery blood wall thickening observed by hematoxylin and eosin staining; the expression of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in the rat lung tissues were determined using immunohistochemistry. Both preventive (12.53 ± 3.8 vs. model control 28.67 ± 7.57 mmHg, P < 0.01) and remedial (35.95 ± 20.29 vs. model control 66.17 ± 24.29 mmHg, P < 0.01) applications of ETN could significantly reduce mPAP. We obtained similar results when using the R-value to assess the efficacy of ETN in two treatment groups (preventive groups, 0.273 ± 0.018 vs. 0.203 ± 0.036, P < 0.01; remedial groups, 0.227 ± 0.031 vs. 0.124 ± 0.008, P < 0.01). The immunohistochemistry staining showed that there were strong expressions of TNF-α and IL-6 in the lung tissues of model groups and decreased expression in both treatment groups. Treatment with TNF-α antagonism ETN prevented and reversed MCT-induced PAH by reducing inflammatory cell infiltration. Our results suggest a critical role of TNF-α and inflammation in MCT-induced PAH progression and targeting the inflammatory environment might be a potential means of PAH treatment.

Role of Tumor Necrosis Factor-α in the Human Systemic Endotoxin-Induced Transcriptome

TNFα has been implicated in the pathogenesis of various inflammatory diseases. Different strategies to inhibit TNFα in patients with sepsis and chronic inflammatory conditions have shown contrasting outcomes. Although TNFα inhibitors are widely used in clinical practice, the impact of TNFα antagonism on white blood cell gene expression profiles during acute inflammation in humans in vivo has not been assessed. We here leveraged the established model of human endotoxemia to examine the effect of the TNFα antagonist, etanercept, on the genome-wide transcriptional responses in circulating leukocytes induced by intravenous LPS administration in male subjects. Etanercept pre-treatment resulted in a markedly dampened transcriptional response to LPS. Gene co-expression network analysis revealed this LPS-induced transcriptome can be categorized as TNFα responsive and non-responsive modules. Highly significant TNFα responsive modules include NF-kB signaling, antiviral responses and T-cell mediated responses. Within these TNFα responsive modules we delineate fundamental genes involved in epigenetic modifications, transcriptional initiation and elongation. Thus, we provide comprehensive information about molecular pathways that might be targeted by therapeutic interventions that seek to inhibit TNFα activity during human inflammatory diseases.

Suprachiasmatic Astrocytes Modulate the Circadian Clock in Response to TNF-α

The immune and the circadian systems interact in a bidirectional fashion. The master circadian oscillator, located in the suprachiasmatic nuclei (SCN) of the hypothalamus, responds to peripheral and local immune stimuli, such as proinflammatory cytokines and bacterial endotoxin. Astrocytes exert several immune functions in the CNS, and there is growing evidence that points toward a role of these cells in the regulation of circadian rhythms. The aim of this work was to assess the response of SCN astrocytes to immune stimuli, particularly to the proinflammatory cytokine TNF-α. TNF-α applied to cultures of SCN astrocytes from Per2(luc) knockin mice altered both the phase and amplitude of PER2 expression rhythms, in a phase-dependent manner. Furthermore, conditioned media from SCN astrocyte cultures transiently challenged with TNF-α induced an increase in Per1 expression in NIH 3T3 cells, which was blocked by TNF-α antagonism. In addition, these conditioned media could induce phase shifts in SCN PER2 rhythms and, when administered intracerebroventricularly, induced phase delays in behavioral circadian rhythms and SCN activation in control mice, but not in TNFR-1 mutants. In summary, our results show that TNF-α modulates the molecular clock of SCN astrocytes in vitro, and also that, in response to this molecule, SCN astrocytes can modulate clock gene expression in other cells and tissues, and induce phase shifts in a circadian behavioral output in vivo. These findings suggest a role for astroglial cells in the alteration of circadian timing by immune activation.

Trichostatin A Modulates Thiazolidinedione-Mediated Suppression of Tumor Necrosis Factor α-Induced Lipolysis in 3T3-L1 Adipocytes

In obesity, high levels of tumor necrosis factor α (TNFα) stimulate lipolysis in adipocytes, leading to hyperlipidemia and insulin resistance. Thiazolidinediones (TZDs), the insulin-sensitizing drugs, antagonize TNFα-induced lipolysis in adipocytes, thereby increasing insulin sensitivity in diabetes patients. The cellular target of TZDs is peroxisome proliferator-activated receptor γ (PPARγ), a nuclear receptor that controls many adipocyte functions. As a transcription factor, PPARγ is closely modulated by coregulators, which include coactivators and corepressors. Previous studies have revealed that in macrophages, the insulin-sensitizing effect of PPARγ may involve suppression of proinflammatory gene expression by recruiting the corepressor complex that contains corepressors and histone deacetylases (HDACs). Therefore, we investigated whether the corepressor complex is involved in TZD-mediated suppression of TNFα-induced lipolysis in 3T3-L1 adipocytes. Trichostatin A (TSA), a pan HDAC inhibitor (HDACI) that inhibits class I and II HDACs, was used to examine the involvement of HDACs in the actions of TZDs. TSA alone increased basal lipolysis and attenuated TZD-mediated suppression of TNFα-induced lipolysis. Increased basal lipolysis may in part result from class I HDAC inhibition because selective class I HDACI treatment had similar results. However, attenuation of TZD-mediated TNFα antagonism may be specific to TSA and related hydroxamate-based HDACI rather than to HDAC inhibition. Consistently, corepressor depletion did not affect TZD-mediated suppression. Interestingly, TSA treatment greatly reduced PPARγ levels in differentiated adipocytes. Finally, extracellular signal-related kinase 1/2 (ERK1/2) mediated TNFα-induced lipolysis, and TZDs suppressed TNFα-induced ERK phosphorylation. We determined that TSA increased basal ERK phosphorylation, and attenuated TZD-mediated suppression of TNFα-induced ERK phosphorylation, consistent with TSA’s effects on lipolysis. These studies suggest that TSA, through down-regulating PPARγ, attenuates TZD-mediated suppression of TNFα-induced ERK phosphorylation and lipolysis in adipocytes.

C-C motif chemokine receptor 9 positive macrophages activate hepatic stellate cells and promote liver fibrosis in mice

Chemokine receptors mediate migration of immune cells into the liver, thereby promoting liver inflammation. C-C motif chemokine receptor (CCR) 9(+) macrophages are crucial in the pathogenesis of acute liver inflammation, but the role and underlying mechanisms of this macrophage subset in chronic liver injury and subsequent liver fibrosis are not fully understood. We confirmed that tumor necrosis factor alpha (TNF-α)-producing CCR9(+) macrophages accumulated during the initiation of carbon tetrachloride (CCl4 )-induced liver injury, and CCR9 deficiency attenuated the degree of liver damage. Accumulation of CCR9(+) macrophages persisted prominently during the process of liver fibrosis induced by repetitive CCl4 or thioacetamide (TAA)/leptin administration. Increased CCR9 expression was also found on activated hepatic stellate cells (HSCs). Importantly, experimental liver fibrosis was significantly ameliorated in CCR9(-/-) mice compared with wild-type (WT) mice, assessed by α-smooth muscle actin (α-SMA) immunostain, Sirius red staining, and messenger RNA (mRNA) expression levels of α-SMA, collagen 1α1, transforming growth factor (TGF)-β1, and tissue inhibitor of metalloproteinase (TIMP)-1. Accumulated CD11b(+) macrophages in CCl4 -treated WT mice showed marked increases in TNF, NO synthase-2, and TGF-β1 mRNA expression compared with CCR9(-/-) mice, implying proinflammatory and profibrogenic properties. Hepatic CD11b(+) macrophages from CCl4 -treated WT mice (i.e., CCR9(+) macrophages), but not CD8(+) T lymphocytes or non-CD11b(+) cells, significantly activated HSCs in vitro compared with those from CCR9(-/-) mice. TNF-α or TGF-β1 antagonism attenuated CCR9(+) macrophage-induced HSC activation. Furthermore, C-C motif chemokine ligand (CCL) 25 mediated migration and, to a lesser extent, activation of HSCs in vitro. Accumulated CD11b(+) macrophages are critical for activating HSCs through the CCR9/CCL25 axis and therefore promote liver fibrosis. CCR9 antagonism might be a novel therapeutic target for liver fibrosis.

Cardiovascular effects of tumour necrosis factor α antagonism in patients with acute myocardial infarction: a first in human study

ObjectiveThe inflammatory cytokine, tumour necrosis factor α (TNF-α), exerts deleterious cardiovascular effects. We wished to determine the effects of TNF-α antagonism on endothelial function and platelet activation in patients with...

Protective effects of a novel trimerized sTNFRII on acute liver injury

TNF α plays a central role in the pathogenesis of inflammatory diseases such as rheumatoid arthritis and murine acute liver injury induced by injection of d-galactosamine and subsequent LPS. Recombinant Fc-fused soluble TNF receptor II (sTNFRII-Fc) has been used in the treatment of rheumatoid arthritis for a decade. We have recently constructed a novel fusion protein sTNFRII-gAD, which is composed of a soluble TNF receptor II and a globular domain of adiponectin. Utilizing the inclination of gAD to form homologous trimer naturally, we sought to explore TNFα antagonism of the novel trimerized sTNFRII-gAD and meantime compare TNFα-neutralizing effects in vitro and in vivo between sTNFRII-Fc and sTNFRII-gAD. Here, we evaluated the TNFα-antagonizing activity of sTNFRII-gAD with TNFα-induced L929 cytotoxicity assay. Furthermore, sTNFRII-Fc or sTNFRII-gAD was administered simultaneously with d-galactosamine 1h prior to LPS injection in the murine model of acute liver injury. Serum TNFα and TNFα-sTNFRII-gAD complex were measured by ELISA and the liver injury was assessed through alanine transaminase measurement and liver histological analysis. sTNFRII-gAD was shown to have higher TNFα-neutralizing activity than sTNFRII-Fc (p<0.05) in the L929 cytotoxicity assay. With a significant attenuation of murine lethality (p<0.05), sTNFRII-gAD showed more protective effects than sTNFRII-Fc in the murine model of acute liver injury. These results demonstrated that sTNFRII-gAD was more efficacious than sTNFRII-Fc as a TNFα antagonist, highlighting the potential of sTNFRII-gAD for the treatment of diseases associated with excessive TNFα.

CCR5 Deficiency Mitigates the Deleterious Effects of Tumor Necrosis Factor α Antagonism in Murine Histoplasmosis

In murine histoplasmosis, tumor necrosis factor α (TNF-α) antagonism increases the number of regulatory T cells (Tregs) in lungs, and these cells profoundly hinder protective immunity. Because CCR5 mediates Treg homing and proliferation, we determined the outcome of antagonizing TNF-α in CCR5(-/)(-) mice infected with Histoplasma capsulatum. The absence of CCR5 attenuated the severity of infection associated with TNF-α neutralization. Infected controls given anti-TNF-α had a 10-fold increase in the number of Tregs in lungs compared with a <2-fold increase in CCR5(-/)(-) lungs. This difference was partially attributable to impaired homing in the absence of CCR5. Neutralization of TNF-α-enhanced CCR5 ligands in wild-type lungs thus promotes a gradient between lungs and the thymus. This study elucidates the interplay between TNF-α and CCR5 in histoplasmosis. The data suggest that targeting CCR5 may improve host immunity in individuals receiving TNF-α antagonists during infection.

Rehabilitation Treatment Strategies in Ankylosing Spondylitis

To the Editor: We read with great interest the recent article by Masiero, et al regarding the efficacy of exercise combined with an educational-behavioral program in patients with stabilized ankylosing spondylitis (AS)1. We agree that physical therapy has remained a mainstay for the treatment of AS in order to reduce pain, preserve spinal flexibility, prevent postural deformities, and improve muscle strength. Although tumor necrosis factor-α (TNF-α) antagonism has dramatically changed the … Address correspondence to Dr. Colina; E-mail: matteo.colina{at}gmail.com

Effect of tumor necrosis factor-α antagonism in asthma: a meta-analysis of the published literature

It remains controversial whether tumor necrosis factor (TNF)-α antagonism is effective for asthma. This meta-analysis was performed to evaluate efficacy of TNF-α antagonism in treatment of patients with asthma. MEDLINE, EMBASE, LILACS, and CINAHL databases were searched for English-language studies published through January 3, 2010. Randomized-controlled trials comparing TNF-α antagonism with control therapy were selected. For each report, data were extracted in relation to the outcomes analyzed: asthma exacerbation, asthma quality of life questionnaire scores, and forced expiratory volume in 1 second. Four assessable trials were identified including 641 patients with asthma. TNF-α antagonism therapy was superior to control therapy in preventing exacerbations in asthmatics [pooled odds ratio 0.52 (95% confidence interval 0.29-0.88), P=0.02]; however, there was a nonsignificant reduction in asthma quality of life questionnaire scores [0.23 (0 to 0.47), P=0.05], forced expiratory volume in 1 second [0.03, (-0.14 to 0.10), P=0.74] when analyzed using standardized mean differences. TNF-α antagonism was superior to control chemotherapy in terms of asthma exacerbation, but not asthma quality of life questionnaire scores or forced expiratory volume in 1 second.

Inflammation, Immunity, and Hypertension

Aprominent pathology textbook used in the United States includes an image illustrating the renal histopathology caused by malignant hypertension. The legend describes striking “onion skin” changes of a renal arteriole. Curiously, a sea of mononuclear inflammatory cells surrounding this arteriole is overlooked both in the legend and in the related text. Moreover, nothing regarding inflammation or immune reactions is discussed. This lack of attention to inflammatory cells is, however, not surprising. Although many experimental studies have implicated inflammation in hypertension, these have largely been performed in experimental animals; there is no proof that inflammation contributes to human hypertension. In fact, some anti-inflammatory or immune-suppressing drugs (eg, nonsteroidal anti-inflammatory drugs and cyclosporine) paradoxically cause hypertension in humans, likely via off-target effects. Often the term “inflammation” is used in the context of cardiovascular disease as a catchall referring to nonspecific phenomena, such as elevation of C-reactive protein or the presence of macrophages in a tissue. Most clinicians and investigators find this vague and difficult to understand. Even more puzzling is that many studies now implicate the adaptive immune response, and in particular, lymphocytes, in hypertension and vascular disease. Traditionally, bacterial, viral, or tumor antigens activate this arm of immune defense. As such, it has been hard to imagine how adaptive immunity could be involved in a disease such as hypertension. In this article, we will attempt to address some of these puzzling questions. We will briefly review components of the innate and adaptive immune response, discuss data from many groups, including our own, that suggest that common forms of hypertension are immune mediated, and provide a working hypothesis of how signals from the central nervous system trigger an immune response that causes hypertension. ### General Concepts Regarding Inflammation and Immunity #### Innate Immunity The first line of defense against pathogens is the innate immune response. Important components of this system include epithelial …

TNF-α Antagonism with Etanercept Decreases Glucose and Increases the Proportion of High Molecular Weight Adiponectin in Obese Subjects with Features of the Metabolic Syndrome

Obesity is associated with activation of the TNF-α system, increased inflammatory markers, and insulin resistance. Although studies in rodents suggest that attenuation of TNF activity improves glucose homeostasis, the effect of prolonged inhibition of TNF-α with etanercept on inflammation and glucose homeostasis in a human model of obesity is not known. Forty obese subjects with features of metabolic syndrome were randomized to etanercept or placebo, 50 mg twice weekly for 3 months, followed by 50 mg once weekly for 3 months. Subjects underwent oral glucose tolerance testing and measurement of serum inflammatory biomarkers and adipokines. Subcutaneous fat biopsy was performed in a subset for measurement of adipokine and TNF-α mRNA expression. Visceral adiposity was significantly associated with serum concentrations of TNF receptor 1 (TNFR1), TNFR2, and vascular cell adhesion molecule-1 and adipose tissue expression of TNF-α and SOCS-3 (all P < 0.05). Insulin resistance as assessed by homeostasis model assessment was significantly associated with TNFR1, C-reactive protein, IL-6, and soluble intracellular adhesion molecule-1 (sICAM-1) (all P < 0.05). Etanercept significantly improved fasting glucose (treatment effect vs. placebo over 6 months, -10.8 ± 4.4%, P = 0.02). Etanercept also increased the ratio of high molecular weight adiponectin to total adiponectin (+22.1 ± 9.2% vs. placebo, P = 0.02), and decreased levels of sICAM-1 (-11 ± 2% vs. placebo, P < 0.0001). In contrast, body composition, lipids, C-reactive protein, and IL-6 were unchanged after 6 months. Prolonged therapy with etanercept improved fasting glucose, increased the ratio of high molecular weight to total adiponectin, and decreased sICAM-1 in obese subjects with abnormal glucose homeostasis and significant subclinical inflammation.