Involvement Of Tumor Necrosis Factor-alpha Research Articles

Antinociceptive effect of the hydroethanolic leaf extract of Calotropis procera (Ait) R. Br. (Apocynaceae): Possible involvement of glutamatergic, cytokines, opioidergic and adenosinergic pathways

Ethnopharmacological relevancePain remains real and still a major problem in clinical medicine which requires new agents with improved efficacy for more therapeutic benefits. Plant sources can serve as a basis for the search for some novel drugs hence the analgesic effects of the hydroethanolic extract of Calotropis procera (CPE) which is widespread in Ghana and other tropical areas and used in folkloric medicine for painful and inflammatory conditions was evaluated. Materials and methodsThe analgesic properties of orally administered CPE at doses of 30, 100, and 300 mg/kg were evaluated in thermal (tail immersion), chemical (acetic acid-writhing, formalin-induced paw licking, glutamate-induced nociception) and mechanical (Randall-Selitto) tests for analgesia. The involvement of tumour necrosis factor-alpha (TNF-α), interleukin 1β (IL 1β), bradykinin, and prostaglandin E2 (PGE2) on the analgesic effects of CPE were also evaluated in hypernociception assays measuring mechanical pain thresholds. ResultsThe latency of tail withdrawal in the tail immersion test was significantly increased (p = 0.0001) while writhing induced by acetic acid was significantly reduced (p < 0.0001) on treatment with CPE (30–300 mg/kg). The extract also significantly inhibited both phase 1 and phase 2 nociceptive states induced by formalin comparable to morphine (p < 0.0001). Furthermore, the extract significantly attenuated hyper-nociception induced by TNF-α (p < 0.0001), interleukin 1β (p = 0.0102), bradykinin (p < 0.0001), and prostaglandin E2 (p < 0.0001). Additionally, glutamate-induced paw licking was reduced significantly (p < 0.05). The antinociceptive effects exhibited by CPE (100 mg/kg) in the formalin test was reversed by systemic administration of naloxone (2 mg/kg) and theophylline (5 mg/kg) but not glibenclamide (8 mg/kg), granisetron (2 mg/kg), atropine (3 mg/kg), yohimbine (3 mg/kg, p.o.) nor nifedipine (10 mg/kg). ConclusionOverall, the hydroethanolic leaf extract of Calotropis procera possesses analgesic properties that is mediated possibly through the glutaminergic, opioidergic, and adenosinergic pathways.

Byrsonima intermedia A. Juss partitions promote gastroprotection against peptic ulcers and improve healing through antioxidant and anti-inflammatory activities

Byrsonima intermedia is a species of bush popularly used to treat gastrointestinal disorders, such as gastric ulcers, gastritis, and diarrhea. Previous studies have revealed that the methanolic crude extract of B. intermedia leaves has gastroprotective and healing properties. In this new study, we specifically investigated two purified partitions, ethyl acetate (EtOAc) and water (AcoAq), obtained from the crude extract to characterize the antiulcer effects of these two partitions and the mechanisms of action of this medicinal plant. The healing effects of these partitions on the gastric and duodenal mucosa were assessed after ischemia-reperfusion (I/R) or acetic acid-induced injury. The involvement of tumor necrosis factor-alpha (TNF-alpha), interleukin 1β (IL-1β), interleukin 10 (IL-10), and myeloperoxidase (MPO) activity and glutathione (GSH) levels were determined. The antibacterial activity against Helicobacter pylori was evaluated using microdilution methods. The phytochemical analysis of AcoAq revealed a predominance of oligomeric proanthocyanidins and galloyl quinic esters, whereas EtOAc was found to contain concentrated flavonoids. Both partitions led to a significant reduction in gastric lesions, but AcoAq was more effective than EtOAc with regard to anti-Helicobacter pylori activity in addition to protecting the gastric mucosa against ethanol, non-steroidal anti-inflammatory drugs (NSAIDs) and duodenal mucosal damage induced by cysteamine.Additionally, both partitions were associated with a significant increase in gastric and duodenal healing and increased gastric mucosal GSH content after damage induced by acetic acid. On the other hand, after 6 days of treatment, EtOAc was more effective than AcoAq in ameliorating gastric damage upon initiation of the gastric I/R, which was accompanied by a significant reduction in the activity of gastric mucosal MPO, IL 1-β and TNF-alpha, as well as an elevation in IL-10 and GSH content. These results demonstrate that the oligomeric proanthocyanidins and galloyl quinic esters present in AcoAq were more effective in the prevention of gastric and duodenal ulcers due to the antioxidant effects of these compounds, whereas the flavonoids present in EtOAc were more effective due to their anti-inflammatory activity on the gastric and duodenal tissue. All these results confirm that the rich phytochemical diversity of B. intermedia contributes to the pharmacological actions of this medicinal plant on the gastrointestinal tract in addition to its activity against H. pylori.

Leptin Mediates In Vivo Neutrophil Migration: Involvement of Tumor Necrosis Factor-Alpha and CXCL1.

Leptin directly activates macrophages and lymphocytes, but the role of leptin in neutrophil activation and migration is still controversial. Here, we investigate the in vivo mechanisms of neutrophil migration induced by leptin. The intraperitoneal injection of leptin (1 mg/kg) induces a time- and concentration-dependent neutrophil influx. We did not observe the enhancement of lipid bodies/droplets in neutrophils, after leptin treatment, as we had observed previously in peritoneal macrophages. The participation of leukotriene B4 (LTB4) in neutrophil recruitment triggered by leptin was investigated using different strategies. Leptin-induced neutrophil recruitment occurs both in the absence of 5-lipoxygenase activity in 5-lipoxygenase (5-LO)−/− mice and after the administration of either 5-LO inhibitor (Zileuton) or the LTB4 receptor antagonist (U-75302). Moreover, no direct induction of LTB4 by leptin could be observed. Neutrophil influx could not be prevented by the mammalian target of rapamycin (mTOR) inhibitor, rapamycin, contrasting with the leptin-induced signaling for lipid body formation in macrophage that is mTOR-dependent. Leptin administration led to tumor necrosis factor-alpha (TNFα) production by the peritoneal cells both in vivo and in vitro. In addition, neutrophil recruitment was inhibited in tumor necrosis factor receptor 1 (TNFR1−/−) mice, indicating a role for TNF in leptin-induced neutrophil recruitment to the peritoneal cavity. Leptin-induced neutrophil influx was PI3Kγ-dependent, as it was absent in PI3Kγ−/− mice. Accordingly, leptin induced the peritoneal cells to produce CXCL1, both in vivo and in vitro, and the neutrophil influx was ablated after using an antibody against CXCL1. Our results establish TNFα/TNFR1- and CXCL1-dependent signaling as important pathways for leptin-induced neutrophil migration in vivo.

Chemical Burns of the Eye: The Role of Retinal Injury and New Therapeutic Possibilities.

To propose a new treatment paradigm for chemical burns to the eye - in the acute and chronic phases. Recent laboratory and clinical data on the biology and treatment of chemical burns are analyzed. Corneal blindness from chemical burns can now be successfully treated with a keratoprosthesis, on immediate and intermediate bases. Long term outcomes, however, are hampered by early retinal damage causing glaucoma. New data suggest that rapid diffusion of inflammatory cytokines posteriorly (TNF-α, etc) can severely damage the ganglion cells. Prompt anti-TNF-α treatment is markedly neuroprotective. Long term profound reduction of the intraocular pressure is also vital. A new regimen, in addition to standard treatment, for severe chemical burns is proposed. This involves tumor necrosis factor alpha (TNF-α) inhibition promptly after the accident (primarily for retinal neuroprotection), prophylactic maximal lowering of the intraocular pressure (starting immediately), and keratoprosthesis implantation in a later quiet state.

Tumor Necrosis Factor-alpha Adversely Influences Myocardial Oxygen Demand and Exercise Tolerance in Postmenopausal Women

Oxidative stress-mediated arterial stiffening is related to the pathophysiological progression of vascular dysfunction with advancing age. However, the functional implications concerning the involvement of tumor necrosis factor-alpha (TNF-α), a marker of oxidative stress, on hemodynamic responses at rest and during physical exertion are unclear. PURPOSE: The aims of this investigation were to examine the independent effects of TNF-α on myocardial oxygen demand at rest and during submaximal exercise, while also evaluating the influence of TNF-α on exercise tolerance. METHODS: Forty, postmenopausal (65 ± 3 years) women, provided blood samples and completed a modified-Balke protocol to measure maximal oxygen uptake. Local pulse contour analyses were used to assess large artery compliance while rate-pressure product (RPP), a reliable index of myocardial oxygen demand, was measured at rest and during two submaximal workloads. RPP was calculated by dividing the product of heart rate and systolic blood pressure (via auscultation) by 100. Exercise tolerance corresponded with the cessation of the graded exercise test. P-values ≤ 0.05 were considered statistically significant for all analyses. RESULTS: Multiple linear regression revealed a positive association between TNF-α and RPP during submaximal exercise (partial r = 0.43; p = 0.015) adjusted for maximal heart rate, maximal oxygen uptake, large artery compliance, and percent body fat. Path analyses revealed a significant indirect effect of large artery compliance on exercise tolerance through TNF-α, β = 0.13, CI [0.03, 0.35] such that heightened levels of TNF-α translated to poorer exercise tolerance. CONCLUSIONS: These data indicate that TNF-α is independently associated with myocardial oxygen demand during submaximal exercise equating to 5 METs but not at rest and TNF-α mediates the indirect effects of large artery compliance on exercise tolerance. Future studies should explore differential responses to standardized exercise tasks among older adults and consider the influence of exercise training on myocardial oxygen demand and activity-related energy expenditure.

Syndrome d’entérocolite induite par les protéines alimentaires (SEIPA) : à propos d’une observation de diarrhée avec choc hypovolémique et méthémoglobinémie

We report on the case of a young infant with chronic diarrhea that worsened and turned into hypovolemic shock with methemoglobinemia. We underline and discuss the main features of food protein-induced enterocolitis syndrome (FPIES). FPIES is a non-IgE-mediated food allergy involving tumor necrosis factor-alpha (TNF-α). Many triggering foods exist but cow's milk, as in the case reported herein, is one of the most frequent. It can start early or be delayed and start around the average age of 5months. Symptoms are nonspecific with diarrhea and vomiting, but in the presence of methemoglobinemia, the diagnosis must be seriously considered. The oral food challenge remains the gold standard to confirm the diagnosis if there is still a doubt. Treatment of FPIES associates emergency treatment of acute dehydration with the prevention of relapses by avoiding the suspected protein.

The role of TNF-α in rheumatoid arthritis: a focus on regulatory T cells

The autoimmune disorder rheumatoid arthritis (RA) causes chronic inflammation and destruction of joints. T cells are a predominant component of the synovial environment in RA, however the functional role of these cells is not yet fully understood. This is in part due to the fact that the balance and importance of the relation of Tregs with T-effector cells in RA is still under investigation. The current treatment regimen for this debilitating disease focuses on controlling symptoms and preventing further joint damage through the use of therapies which affect different areas of the immune system at the synovium. One of the main therapies involves Tumor Necrosis Factor alpha (TNF-α) inhibitors. In the RA immune-environment, TNF-α has been shown to have an influential and extensive but as yet poorly understood effect on Treg function in vivo, and undoubtably an important role in the treatment of RA. Interestingly, the high levels of TNF-α found in RA patients appear to interfere with the mechanisms controlling the suppressive function of Tregs. Relevance for patients: This review focuses on the conflicting literature available regarding the role played by Tregs in RA and the impact of TNF-α and anti-TNF-α therapies on Tregs in this scenario. Individuals suffering from RA can benefit from better insight of the treatment mechanisms of the immunologic processes which occur throughout this disease, as current treatments for RA focus on several different areas of the immune system at the synovial compartment.

Role of toll-like receptor 4 in melatonin-induced cardioprotection.

Melatonin protects the heart against myocardial ischemia/reperfusion injury via the activation of the survivor activating factor enhancement (SAFE) pathway which involves tumor necrosis factor alpha (TNFα) and the signal transducer and activator of transcription 3 (STAT3). Toll-like receptor 4 (TLR4) plays a crucial role in myocardial ischemia/reperfusion injury and activates TNFα. In this study, we investigated whether melatonin may target TLR4 to activate the SAFE pathway. Isolated hearts from rats or mice were subjected to ischemia/reperfusion injury. Melatonin (75 ng/L) and/or TAK242 (a specific inhibitor of TLR4 signaling, 500 nm) were administered to the rat hearts before the induction of ischemia. Pre-ischemic myocardial STAT3 was evaluated by Western blotting. Lipopolysaccharide (LPS, a stimulator of TLR4) was administered to wild type, TNFα receptor 2 knockout or cardiomyocyte-specific STAT3-deficient mice (2.8 mg/kg, i.p) 45 min before the heart isolation. Myocardial infarct size was measured as an endpoint. Compared to the control, administration of melatonin reduced myocardial infarct size (34.7 ± 2.8% versus 62.6 ± 2.7%, P < 0.01). This protective effect was abolished in the presence of TAK242 (49.2 ± 6.5%). Melatonin administered alone increased the pre-ischemic activation of mitochondrial STAT3, and this effect was attenuated with TAK242. Furthermore, stimulation of TLR4 with LPS pretreatment to mice reduced myocardial infarct size of the hearts isolated from wild-type animals but failed to protect the hearts isolated from TNFα receptor 2-knockout mice or cardiomyocyte-specific STAT3-deficient mice (P < 0.001). Taken together, these data suggest that cardioprotection induced by melatonin is mediated by TLR4 to activate the SAFE pathway.

HIV-1 Tat Protein Induces PD-L1 (B7-H1) Expression on Dendritic Cells through Tumor Necrosis Factor Alpha- and Toll-Like Receptor 4-Mediated Mechanisms

Chronic human immunodeficiency virus type 1 (HIV-1) infection is associated with induction of T-cell coinhibitory pathways. However, the mechanisms by which HIV-1 induces upregulation of coinhibitory molecules remain to be fully elucidated. The aim of the present study was to determine whether and how HIV-1 Tat protein, an immunosuppressive viral factor, induces the PD-1/PD-L1 coinhibitory pathway on human dendritic cells (DCs). We found that treatment of DCs with whole HIV-1 Tat protein significantly upregulated the level of expression of PD-L1. This PD-L1 upregulation was observed in monocyte-derived dendritic cells (MoDCs) obtained from either uninfected or HIV-1-infected patients as well as in primary myeloid DCs from HIV-negative donors. In contrast, no effect on the expression of PD-L2 or PD-1 molecules was detected. The induction of PD-L1 on MoDCs by HIV-1 Tat (i) occurred in dose- and time-dependent manners, (ii) was mediated by the N-terminal 1-45 fragment of Tat, (iii) did not require direct cell-cell contact but appeared rather to be mediated by soluble factor(s), (iv) was abrogated following neutralization of tumor necrosis factor alpha (TNF-α) or blocking of Toll-like receptor 4 (TLR4), (v) was absent in TLR4-knockoout (KO) mice but could be restored following incubation with Tat-conditioned medium from wild-type DCs, (vi) impaired the capacity of MoDCs to functionally stimulate T cells, and (vii) was not reversed functionally following PD-1/PD-L1 pathway blockade, suggesting the implication of other Tat-mediated coinhibitory pathways. Our results demonstrate that HIV-1 Tat protein upregulates PD-L1 expression on MoDCs through TNF-α- and TLR4-mediated mechanisms, functionally compromising the ability of DCs to stimulate T cells. The findings offer a novel potential molecular target for the development of an anti-HIV-1 treatment. The objective of this study was to investigate the effect of human immunodeficiency virus type 1 (HIV-1) Tat on the PD-1/PD-L1 coinhibitory pathway on human monocyte-derived dendritic cells (MoDCs). We found that treatment of MoDCs from either healthy or HIV-1-infected patients with HIV-1 Tat protein stimulated the expression of PD-L1. We demonstrate that this stimulation was mediated through an indirect mechanism, involving tumor necrosis factor alpha (TNF-α) and Toll-like receptor 4 (TLR4) pathways, and resulted in compromised ability of Tat-treated MoDCs to functionally stimulate T-cell proliferation.

Sepsis-induced changes in behavioral stereotypy in rats; involvement of tumor necrosis factor-alpha, oxidative stress, and dopamine turnover

BackgroundSepsis-associated encephalopathy (SAE) is defined as a diffuse or multifocal cerebral dysfunction that generally occurs early during severe sepsis. The complete pathophysiology of SAE is unknown, but several mechanisms including endotoxins, inflammatory mediators, the alteration of amino acids and of neurotransmitters, apoptosis, oxidative stress, and blood-brain barrier dysfunction have been suggested. The aim of the present study was to explore the relationship between behavioral stereotypy and plasma levels of tumor necrosis factor-alpha (TNF-α) and malondialdehyde (a marker of lipid peroxidation), and brain homovanillic acid content (a marker of dopamine turnover) in a surgically induced sepsis model in rats. Materials and methodsTwenty-two adult male Sprague Dawley rats were included in the study. The cecal ligation and puncture procedure was performed to induce sepsis model. Apomorphine-induced stereotypy test was achieved 24 h after cecal ligation and puncture surgery and then, blood and brain samples were collected for biochemical measurements. ResultsSignificantly higher stereotypy score was found in sepsis group than in the sham group (P = 0.008). Furthermore, septic rats revealed significantly higher plasma TNF-α (P = 0.002) and malondialdehyde levels (P = 0.002), and brain homovanillic acid (P = 0.004) compared with sham rats. There was a significant and positive correlation between the behavioral and biochemical parameters. ConclusionsTaken together, these results demonstrate the association between inflammatory response, oxidative stress, and stereotypic behavior in an experimental sepsis model. More comprehensive experimental and clinical studies are required to clarify the specific mechanisms underlying SAE.

Multimechanistic antifibrotic effect of biochanin a in rats: implications of proinflammatory and profibrogenic mediators.

ObjectiveBiochanin A (BCA) is an isoflavone found in red clover and peanuts. Recently, it drew much attention as a promising anticancer and antioxidant. Due to its diversity in pharmacological actions, we were encouraged to investigate its potential as an antifibrotic, elucidating the different molecular mechanisms involved.DesignRats were pretreated with BCA, then injected with carbon tetrachloride (CCl4) for 6 weeks. Changes in liver weight and histology were examined and levels of aspartate and alanine aminotransferases, cholesterol, triglycerides, alkaline phosphatase and total bilirubin measured. To assess hepatic efficiency, indocyanine green was injected and its clearance calculated and albumin, total proteins and insulin-like growth factor-1 expression were measured. Cytochrome P4502E1 activity, cytochrome P4501A1 expression, in addition to sulfotransferase1A1 expression were determined to deduce the effect of BCA on hepatic metabolism. As oxidative stress markers, lipid peroxides levels, reduced glutathione, superoxide dismutase and catalase activities, as well as the total antioxidant capacity, were assessed. Nitric oxide, inducible nitric oxide synthase and cyclooxygenase-2 were used as indicators of the inflammatory response. Signaling pathways involving tumor necrosis factor-alpha, nuclear factor-kappa B, transforming growth factor-beta1, matrix metalloproteinase-9 and alpha-smooth muscle actin were investigated accordingly. Extent of fibrosis was examined by Masson’s stain and measuring hydroxyproline levels.ResultsBCA pretreatment significantly protected against the chronic damage of CCl4. Liver injury, oxidative stress, inflammation and fibrosis markers decreased, while hepatic efficiency improved.ConclusionOur findings suggested that BCA administration protects against fibrotic complications, a property that can be contributed to the multimechanistic approach of the drug.

The role of TNF-α and TNF superfamily members in the pathogenesis of calcific aortic valvular disease.

Calcific aortic valve disease (CAVD) represents a slowly progressive pathologic process associated with major morbidity and mortality. The process is characterized by multiple steps: inflammation, fibrosis, and calcification. Numerous studies focalized on its physiopathology highlighting different “actors” for the multiple “acts.” This paper focuses on the role of the tumor necrosis factor superfamily (TNFSF) members in the pathogenesis of CAVD. In particular, we discuss the clinical and experimental studies providing evidence of the involvement of tumor necrosis factor-alpha (TNF-α), receptor activator of nuclear factor-kappa B (NF-κB) ligand (RANKL), its membrane receptor RANK and its decoy receptor osteoprotegerin (OPG), and TNF-related apoptosis-inducing ligand (TRAIL) in valvular calcification.

Association of tumour necrosis factor-alpha −308 G/A promoter polymorphism with susceptibility and disease profile of rheumatoid arthritis

The objective was to analyze the possible involvement of tumour necrosis factor-alpha (TNF-α) -308 G/A promoter polymorphism in the susceptibility and/or the disease profile of rheumatoid arthritis (RA) in Egyptian patients. TNF-α-308 G/promoter polymorphism detection by amplification refractory mutation system (ARMS) technique was carried out for 122 RA patients and 120 healthy controls. TNF-α-308 G allele/GG homozygous genotype were higher in patients with rheumatoid arthritis than those in control group (P < 0.001, respectively). A statistically significant association was found between the frequency of the A allele and presence of erosion (OR = 3.42, P = 0.015). No associations were found between the distribution of TNF-α-308 G/A alleles/genotypes and age of patients, disease duration, absence of remission, presence of deformity, clinical manifestations of the disease and presence or absence of rheumatoid factor. The positivity of rheumatoid factor was associated with occurrence of erosion (OR = 25.0, P < 0.001). The results of this study demonstrate the association of the TNF-α-308 G allele and GG homozygous genotype with susceptibility to RA and the A allele with the presence of erosion in the Egyptian patients.

TNF-α and IL-1β mediate Japanese encephalitis virus-induced RANTES gene expression in astrocytes

Infection with Japanese encephalitis virus (JEV) causes neuroinfection and neuroinflammation characterized by profound neuronal destruction/dysfunction, concomitant microgliosis/astrogliosis, and production of various molecules that initiate the recruitment of immune cells to the sites of infection. Previously, we reported that glial cells expressed RANTES (regulated upon activation, normal T cell expressed and secreted) with chemotactic activity in response to JEV infection. In this study, we further demonstrated that JEV-infected microglia had an additional activity in regulating RANTES production. Both astrocytes and microglia responded to JEV infection by releasing RANTES through a process likely related to viral replication. Independent of infectious virus, supernatants of JEV-infected microglia, but not JEV-infected astrocytes, caused additional RANTES production from astrocytes. Antibody neutralization studies suggested the potential involvement of tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) in mediating additional RANTES production. Treatment of astrocyte cultures with TNF-α and IL-1β caused activation of several signaling molecules and transcription factors crucial to RANTES gene expression, including reactive oxygen species, extracellular signal-regulated kinase, NF-κB, and NF-IL6, increased RANTES gene promoter activity, and provoked RANTES production. As with RANTES, neutralization of bioactive TNF-α and IL-1β caused an attenuation of chemotactic activity from supernatants of mixed glia containing astrocytes and microglia during the course of JEV infection. In conclusion, TNF-α and IL-1β produced by JEV-infected microglia might trigger another mechanism which induces a secondary wave of RANTES gene expression by activating astrocytes. The released RANTES from glial cells might play a role in the recruitment of immune cells during JEV infection.

Chronic Obstructive Pulmonary Disease and Obstructive Sleep Apnea

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea syndrome represent two of the most prevalent chronic respiratory disorders in clinical practice, and cardiovascular diseases represent a major comorbidity in each disorder. The two disorders coexist (overlap syndrome) in approximately 1% of adults but asymptomatic lower airway obstruction together with sleep-disordered breathing is more prevalent. Although obstructive sleep apnea syndrome has similar prevalence in COPD as the general population, and vice versa, factors such as body mass index and smoking influence relationships. Nocturnal oxygen desaturation develops in COPD, independent of apnea/hypopnea, and is more severe in the overlap syndrome, thus predisposing to pulmonary hypertension. Furthermore, upper airway flow limitation contributes to nocturnal desaturation in COPD without apnea/hypopnea. Evidence of systemic inflammation in COPD and sleep apnea, involving C-reactive protein and IL-6, in addition to nuclear factor-kappaB-dependent pathways involving tumor necrosis factor-alpha and IL-8, provides insight into potential basic interactions between both disorders. Furthermore, oxidative stress develops in each disorder, in addition to activation and/or dysfunction of circulating leukocytes. These findings are clinically relevant because systemic inflammation may contribute to the pathogenesis of cardiovascular diseases and the cell/molecular pathways involved are similar to those identified in COPD and sleep apnea. However, the pathophysiological and clinical significance of systemic inflammation in COPD and sleep apnea is not proven, and thus, studies of patients with the overlap syndrome should provide insight into the mechanisms of systemic inflammation in COPD and sleep apnea, in addition to potential relationships with cardiovascular disease.

Bronchial oxidative stress in equine recurrent airway obstruction

Oxidative stress is an important characteristic of hyperactive airway diseases such as recurrent airway obstruction (RAO) in horses. The primary source of oxidative stress in RAO is from the elevated amounts of reactive oxygen species (ROS) liberated from the inflammatory cells. ROS alters signal transduction mechanisms, activate redox‐sensitive transcription factors and regulate pro‐inflammatory gene expressions. Thus, ROS levels have important consequences for pathogenesis, severity and therapeutic management of RAO. The involvement of Tumor necrosis factor‐alpha (TNF alpha) and NFkB are well established in inflammation. Therefore, the objective of the study was to determine oxidative stress in pulmonary bronchial rings of RAO‐affected and unaffected horses and to test the effectiveness of TNF alpha blockade and NFKB to reduce production of ROS. To block TNF‐alpha and NFKB we incubated the rings with Pentoxifylline and PDTC (Pyrrolidinedithiocarbamate), respectively. Bronchial rings were collected from right diaphragmatic lung lobe of RAO‐affected and unaffected horses and the ROS released by the tissues were measured in control tissues and those incubated with the antagonists, using Electron Paramagnetic Resonance (EPR). The results showed that total ROS was greater in RAO‐affected than the unaffected horses. In addition, incubation of the rings with Pentoxifylline and PDTC reduced the ROS level in both groups of horse rings. The study is suggestive of therapeutic value for these agents in RAO‐affected horses to reduce oxidative stress. Supported by LSU‐SVM Equine Health Studies Program.

Characterization of the human CIDEA promoter in fat cells

Cell death-inducing DFFA (DNA fragmentation factor-alpha)-like effector A (CIDEA) is a protein that regulates lipolysis in human adipocytes through cross-talk involving tumor necrosis factor-alpha (TNF-alpha). TNF-alpha downregulates CIDEA mRNA although it is unclear whether this is mediated through transcriptional or post-transcriptional mechanisms. CIDEA has important metabolic effects in human fat cells and genetic variations in the human CIDEA gene have been correlated to the development of obesity. However, little is known about the factors regulating CIDEA expression in human adipocytes. We set out to describe the transcriptional control of human CIDEA. A 1.1-kb genomic fragment upstream of the transcriptional start site (TSS) of human CIDEA was cloned and deletion fragments were generated. Transcriptional activity of the promoter was analyzed by luciferase reporter assays in in vitro-differentiated human adipocytes. The effect of TNF-alpha was assessed in human adipocytes and murine 3T3-L1 cells transfected with deletion fragments of the CIDEA promoter. Protein-DNA interactions were analyzed by electrophoretic mobility shift assays (EMSA). Basal transcriptional activity was found in a 97-bp region upstream of the TSS. We studied the effect of three common haplotypes in the promoter region but found no significant difference in transcriptional activity among them. Incubation of in vitro-differentiated human adipocytes as well as 3T3-L1 cells with TNF-alpha reduced the transcriptional activity of the human CIDEA promoter, demonstrating a direct effect on CIDEA transcription. EMSAs and mutational analysis indicated that this was mediated by a nuclear factor-kappaB (NF-kappaB) site at position -163/-151. We demonstrate that basal transcription of the human CIDEA gene is confined to the 97 first bases upstream of TSS and that TNF-alpha negatively regulates transcription of this gene, which at least in part involves NF-kappaB activation.

Passive immunization against tumour necrosis factor-alpha (TNF-alpha) and IL-1 beta protects from LPS enhancing glomerular injury in nephrotoxic nephritis in rats.

Glomerular injury caused by injection of heterologous anti-glomerular basement membrane antibodies (anti-GBM Ab) is increased in rats pretreated with small doses of bacterial lipopolysaccharide (LPS). We have investigated the involvement of tumour necrosis factor-alpha (TNF-alpha), IL-1 alpha and IL-1 beta in this phenomenon by passive immunization against these cytokines. Anti-TNF-alpha or anti-IL-1 beta antibodies given 1.5 h before the induction of nephritis significantly decreased injury in this model, whether assessed by the magnitude of albuminuria, the prevalence of glomerular capillary thrombi or the intensity of glomerular neutrophil infiltrate. Albuminuria in anti-GBM Ab alone was 11 +/- 3, LPS/anti-GBM Ab 87 +/- 22, and anti-TNF-alpha antibodies/LPS/anti-GBM Ab 21 +/- 6 mg/24 h (mean +/- s.e.) P < 0.05. Passive immunization with antibodies to IL-1 beta had a similar effect (anti-GBM Ab, 0.6 +/- 0.1, LPS/anti-GBM Ab, 92 +/- 19, anti-IL-1 beta antibodies/LPS/anti-GBM Ab 39 +/- 8 mg/24 h, P < 0.05). The prevalence of glomerular capillary thrombi was also reduced significantly by these treatments; from 22 +/- 5% to 4 +/- 1% in the case of anti-TNF-alpha antibodies and 28 +/- 5% to 13 +/- 4% with anti-IL-1 beta antibodies. Similarly, the glomerular neutrophil infiltrate was also reduced by these treatments; from 42 +/- 3 to 25 +/- 1 in the case of anti-TNF-alpha and 47 +/- 2 to 30 +/- 1 with anti-IL-1 beta antibodies. In contrast, passive immunization against IL-1 alpha had no effect on either albumin excretion (4 +/- 3, 83 +/- 22 and 77 +/- 24 mg/24 h), glomerular capillary thrombi (2 +/- 1; 19 +/- 5 and 16 +/- 3) or glomerular neutrophil infiltrate (22 +/- 3; 47 +/- 5 and 48 +/- 5 from the three groups respectively). These results demonstrate that enhanced antibody mediated injury in the kidney is modulated by TNF-alpha and IL-1 beta but not by IL-1 alpha.

Effects of a Hyaluronate-Carboxymethylcellulose Membrane (Seprafilm) on Human Polymorphonuclear Neutrophil Functions

Seprafilm (Genzyme Corp., Cambridge, MA) is safe and effective for reducing adhesion formation in abdominal and pelvic surgery. However, the relationships between Seprafilm and postoperative complications, including intra-abdominal abscess formation and intra-abdominal inflammation, remain controversial. Polymorphonuclear neutrophils (PMNs) play crucial roles in the processes of intra-abdominal inflammation, infection, and abscess formation, and PMNs act as the first line in nonspecific host defense against a wide range of pathogens. The present study evaluates the effect of Seprafilm itself on human PMNs in experimental models in vitro. Human PMNs were isolated from blood samples obtained from 14 healthy volunteers. The functions of the isolated cells were assessed by examining their phagocytosis, apoptosis/necrosis rates, cytokine production, and PMN-elastase release with and without Seprafilm in an in vitro experimental model of inflammation and endotoxin-stimulation. There were no significant differences in the PMN phagocytosis, apoptosis/necrosis rates, cytokine production, or PMN-elastase release into the supernatant after coculture with bacteria between assays with and without Seprafilm. In the PMN stimulation models involving tumor necrosis factor-alpha and lipopolysaccharide, there were no significant differences in cytokine production between assays with and without Seprafilm. Furthermore, a similar experiment measuring cytokine production in the presence of well-dissolved Seprafilm produced corresponding results. Our results suggest Seprafilm itself does not affect the functions of isolated human PMNs in in vitro experimental models of inflammation and endotoxin-stimulation.

Restraining tumor necrosis factor-alpha by thalidomide prevents the Amyloid beta-induced impairment of recognition memory in mice

No effective remedy has currently been realized to prevent the cognitive impairments of Alzheimer's disease (AD). The interruption of the toxic pathways of amyloid beta peptide (Aβ) still remains promising for the treatment. The involvement of tumor necrosis factor-alpha (TNF-α) in the toxicity of Aβ 1–40 in recent reports provide a fresh target for the interruption. In the current study, we evaluated the feasibility of a strategy that target TNF-α to prevent the impairment of memory induced by Aβ. The i.c.v-injection of Aβ 25–35 increased the hippocampal mRNA expression of both TNF-α and inducible nitric oxide synthase (iNOS), of which the former was stronger. The knock-out of TNF-α (TNF-α (−/−)) in mouse prevented the increase of iNOS mRNA induced by Aβ 25–35. Not only the inhibition of iNOS activity but also TNF-α (−/−) prevented the nitration of proteins in the hippocampus and the impairment of recognition memory in mice induced by Aβ 25–35. Daily treatment with thalidomide (20 mg/kg), a preferential degrader of TNF-α mRNA, or i.c.v.-injection of an anti-TNF-α antibody (10 ηg/mouse) prevented the nitration of proteins in the hippocampus and the impairment of recognition memory induced by Aβ 25–35 or Aβ 1–40 in mice. These results suggested the practicability of targeting TNF-α as a preventive strategy against Aβ-mediated cognitive impairments.