Tumor Necrosis Factor-alpha Activity Research Articles

Sustained activation of nuclear factor-κB by reactive oxygen species is involved in the pathogenesis of stress-induced gastric damage in rats

Stress ulceration is a common complication in critically ill patients, but the mechanisms involved are poorly understood. In this study we investigated the temporal activation of the redox-sensitive transcription factor nuclear factor-kappaB and its roles in an experimental model of cold immobilization stress-induced gastric mucosal lesions. Prospective, controlled, and randomized animal study. University research laboratory. Male Sprague-Dawley rats. The rats were subjected to cold immobilization stress for a total of 6 hrs. The temporal profiles of nuclear factor-kappaB activation and expression of tumor necrosis factor-alpha, interleukin-1beta, cytokine-induced neutrophil chemoattractant-1 (CINC-1), intercellular adhesion molecule-1 (ICAM-1), and inducible nitric oxide synthase (iNOS) were determined in the gastric corpus mucosa of stressed rats. To study the roles of nuclear factor-kappaB activation, rats received an intravenous bolus of a specific nuclear factor-kappaB inhibitor Bay 11-7082 (20 mg/kg) 1 hr before stress. For antioxidant administration, rats were treated with intravenous injection of a free radical scavenger pyrrolidine dithiocarbamate (50, 100, and 200 mg/kg) 1 hr before stress. Exposure of rats to 6 hrs of stress led to a rapid and persistent activation of nuclear factor-kappaB, which was associated with transient degradation of inhibitory protein IkappaBalpha and slower but sustained degradation of IkappaBbeta. Nuclear factor-kappaB activation preceded the induction of tumor necrosis factor-alpha, interleukin-1beta, CINC-1, ICAM-1, and iNOS messenger RNAs, all of which were linearly increased with the duration of stress. Bay 11-7082 selectively blocked the stress-induced nuclear factor-kappaB activation and up-regulation of tumor necrosis factor-alpha, interleukin-1beta, CINC-1, ICAM-1, and iNOS messenger RNAs. Inhibition of expression of these proinflammatory genes prevented the increases in myeloperoxidase activity (an indicator of neutrophil infiltration) in gastric mucosa and the development of gastric damage. Pyrrolidine dithiocarbamate dose-dependently inhibited the stress-induced nuclear factor-kappaB pathway activation and consequential proinflammatory gene expression, neutrophil infiltration, and gastric damage, suggesting the involvement of reactive oxygen species in these processes. Sustained activation of nuclear factor-kappaB by reactive oxygen species is an important in vivo mechanism mediating stress-induced gastric inflammatory damage in rats.

Adiponectin as a key player in inflammation

Chronic inflammation has recently been proposed to be a key mediator linking obesity to a cluster of cardiometabolic disorders. Obese adipose tissue, infiltrated with activated macrophages and mast cells, is an important source of systemic inflammation, by secreting dozens of the pro-inflammatory adipokines into the blood stream. One the other hand, adiponectin, an abundant adipokine secreted predominantly from adipocytes, is markedly decreased in obesity and associated inflammatory diseases. Adiponectin exerts its anti-inflammatory actions in several target cells by inhibiting the production and activities of tumor necrosis factor-alpha, preventing the activation of nuclear factor-kappa B, and inducing expression of anti-inflammatory cytokines. In animal models, adiponectin treatment alleviates several obesity-associated inflammatory diseases, such as atherosclerosis, nonalcoholic steatohepatitis, asthma and acute myocardial infarction. In humans, circulating levels of adiponectin are inversely correlated with several well-established markers of inflammation, including C-reactive protein and interleukin-6. Furthermore, anti-inflammatory drugs, such as peroxisome proliferator-activated receptor-gamma agonists, can elevate plasma levels of adiponectin. While the majority of clinical and animal data support the role of adiponectin as an anti-inflammatory, anti-atheroscerotic and anti-diabetic adipokine, a number of recent studies have reported its pro-inflammatory actions in certain conditions. Here, we summarize the pathophysiological roles of adiponectin in inflammation-related disorders, and discuss the potential mechanisms involved, also their implications in adiponectin-targeted pharmacotherapy. Biomedical Reviews 2006, 17: 11-22.

Nonsurgical Management of Osteolysis

Osteolysis remains a common mode of total hip arthroplasty failure. In vitro and animal models have been used to determine the pathophysiology of osteolysis by carefully dissecting the biochemical pathways leading to particulate wear debris and periprosthetic bone loss. Numerous cytokines and inflammatory mediators, including TNF-alpha and IL-1, are critical participants in this cascade and may represent prime targets for pharmacologic intervention. Osteoclasts, the end effector cells involved in the osteolytic process, also represent potential targets. Cell surface receptors on osteoclast precursors, such as receptor activator of NF-kappaB (RANK) (on osteoclasts) and RANK-ligand (RANKL) (on stromal cells), provide opportunities to arrest osteoclast maturation. Enhancing the naturally occurring osteoprotegerin is another recent attempt at modulating osteoclast behavior and a possible target for pharmacologic therapies. Other nonoperative strategies include intercepting tumor necrosis factor-alpha activity, interfering with the RANK-RANKL interaction necessary for osteoclast development and maturation, bisphosphonate therapy, and using viral vectors to deliver genes. Although each of these approaches has potential benefits, there are substantial challenges to effective implementation. Until there is convincing evidence of efficacy in human clinical trials, we recommend vigilant screening and appropriate surgery with component loosening or substantial likelihood of loosening, periprosthetic fracture, or major bone loss.

Lipid Peroxidation Activates Mitogen-Activated Protein Kinases in Testicular Ischemia-Reperfusion Injury

Testicular damage after torsion has been attributed to many mechanisms, of which one is lipid peroxidation of the plasma membrane, which could cause the activation of the mitogen-activated protein kinase family. These proteins are of vital importance for signal transduction pathways and 2 of them, extracellular signal-regulated kinase and c-jun N-terminal kinase, participate in the pathogenesis of testicular ischemia. We investigated whether lipid peroxidation may trigger mitogen-activated protein kinase activation in testicular ischemia-reperfusion. Adult male Sprague-Dawley rats were subjected to 1-hour testicular ischemia, followed by 24 hours of reperfusion. Sham testicular ischemia-reperfusion rats served as controls. Animals were randomized to receive raxofelast, an inhibitor of lipid peroxidation (20 mg/kg intraperitoneally administered 15 minutes before detorsion and 15 minutes after detorsion) or vehicle (1 ml/kg 10% dimethyl sulfoxide/NaCl solution). A group of animals was sacrificed 0, 10, 15, 20, 25 and 30 minutes, and 1, 2 and 3 hours, respectively, after detorsion to evaluate testicular c-jun N-terminal kinase, extracellular signal-regulated kinase and tumor necrosis factor-alpha activation by Western blot analysis, and mRNA expression and conjugated dienes using a spectrophotometer technique. Another group was sacrificed 24 hours after detorsion to evaluate histological alterations. Testicular ischemia-reperfusion injury caused a significant increase in the conjugated diene levels, extracellular signal-regulated kinase c-jun N-terminal kinase activity and tumor necrosis factor-alpha expression in both testes. Furthermore, histological examination revealed marked damage. Raxofelast inhibited these parameters and decreased histological damage. These data suggest that lipid peroxidation triggers extracellular signal-regulated kinase and c-jun N-terminal kinase activation. Furthermore, mitogen-activated protein kinase blockade might represent a potential therapeutic approach to treatment in patients with unilateral testicular torsion.

Early destruction of tumor vasculature in tumor necrosis factor-α-based isolated limb perfusion is responsible for tumor response

Addition of high-dose tumor necrosis factor-alpha to melphalan-based isolated limb perfusion enhances anti-tumor effects impressively. Unfortunately, the mechanism of action of tumor necrosis factor-alpha is still not fully understood. Here, we investigated the effects of tumor necrosis factor-alpha on the tumor microenvironment and on secondary immunological events during and shortly after isolated limb perfusion in soft-tissue sarcoma-bearing rats. Already during isolated limb perfusion, softening of the tumor was observed. Co-administration of tumor necrosis factor-alpha in the isolated limb perfusion with melphalan induced a six-fold enhanced drug accumulation of melphalan in the tumor compared with isolated limb perfusion with melphalan alone. In addition, directly after perfusion with tumor necrosis factor-alpha plus melphalan, over a time-frame of 30 min, vascular destruction, erythrocyte extravasation and hemorrhage was detected. Interstitial fluid pressure and pH in the tumor, however, were not altered by tumor necrosis factor-alpha and no clear immune effects, cellular infiltration or cytokine expression were observed. Taken together, these results indicate that tumor necrosis factor-alpha induces rapid damage to the tumor vascular endothelial lining resulting in augmented drug accumulation. As other important parameters were not changed (e.g. interstitial fluid pressure and pH), we speculate that the tumor vascular changes, and concurrent hemorrhage and drug accumulation are the key explanations for the observed synergistic anti-tumor response.

Anti‐Inflammatory Effect of Cardiac Resynchronization Therapy

Congestive heart failure (CHF) is associated with persistent immune activation. Medical therapy has been shown to exert only limited anti-inflammatory effects. Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in a subset of patients with heart failure, but it is not known whether this treatment affects the immune system as well. To test this hypothesis, eight patients with heart failure scheduled for CRT were investigated for immune activation before and 6 months after CRT treatment. After 6 months, all patients had improved in NYHA-class and LVEF, and there was a statistically significant reduction in serum N-terminal pro brain natriuretic peptide (BNP). Furthermore, there was a statistically significant reduction in plasma levels of the chemokines monocyte chemoattractant protein 1 (MCP-1) and interleukin 8 (IL-8) and the cytokine interleukin 6 (IL-6). We observed no changes in the levels of interleukin 1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), interleukin 10 (IL-10), or complement activation products. There was a significant correlation between changes in BNP and IL-6 (r = 0.74, P = 0.037). Although based upon a limited number of patients, this report indicates that CRT reduces peripheral markers of immune activation in patients with CHF. Further large scale studies are warranted to verify these findings.

Beneficial effect of resveratrol on cholecystokinin-induced experimental pancreatitis

Resveratrol is a phytoalexin with strong antioxidant and anti-inflammatory effects reaching high concentrations in red wine. The aim of our study was to test the effects of resveratrol pretreatment on cholecystokinin-octapeptide (CCK-8)-induced acute pancreatitis in rats. Animals were divided into a control group, a group treated with CCK-8 and a group receiving 10 mg/kg resveratrol prior to CCK-8 administration. Resveratrol ameliorated the CCK-8-induced changes in the laboratory parameters, and reduced the histological damage in the pancreas. The drug failed to improve the pancreatic antioxidant state, but increased the amount of hepatic reduced glutathione and prevented the reduction of hepatic catalase activity. Resveratrol-induced inhibition of nuclear factor kappa B (NF-κB) activation or reduction of the pancreatic tumor necrosis factor-alpha (TNF-α) concentration could not be demonstrated. In conclusion, the beneficial effects of resveratrol on acute pancreatitis seem to be mediated by the antioxidant effect of resveratrol or by an NF-κB-independent anti-inflammatory mechanism.

Expression and activity of inducible nitric oxide synthase and endothelial nitric oxide synthase correlate with ethanol-induced liver injury

To study the expression and activity of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) in rats with ethanol-induced liver injury and their relation with liver damage, activation of nuclear factor-kappaB (NF-kappaB) and tumor necrosis factor-alpha (TNF-alpha) expression in the liver. Female Sprague-Dawley rats were given fish oil (0.5 mL) along with ethanol or isocaloric dextrose daily via gastrogavage for 4 or 6 wk. Liver injury was assessed using serum alanine aminotransferase (ALT) activity and pathological analysis. Liver malondialdehyde (MDA), nitric oxide contents, iNOS and eNOS activity were determined. NF-kappaB p65ìiNOS, eNOS and TNF-alpha protein or mRNA expression in the liver were detected by immunohistochemistry or reverse transcriptase-polymerase chain reaction (RT-PCR). Chronic ethanol gavage for 4 wk caused steatosis, inflammation and necrosis in the liver, and elevated serum ALT activity. Prolonged ethanol administration (6 wk) enhanced the liver damage. These responses were accompanied with increased lipid peroxidation, NO contents, iNOS activity and reduced eNOS activity. NF-kappaB p65, iNOS and TNF-alpha protein or mRNA expression were markedly induced after chronic ethanol gavage, whereas eNOS mRNA expression remained unchanged. The enhanced iNOS activity and expression were positively correlated with the liver damage, especially the necro-inflammation, activation of NF-kappaB, and TNF-alpha mRNA expression. iNOS expression and activity are induced in the liver after chronic ethanol exposure in rats, which are correlated with the liver damage, especially the necro-inflammation, activation of NF-kappaB and TNF-alpha expression. eNOS activity is reduced, but its mRNA expression is not affected.

LMP-420, a small-molecule inhibitor of TNF-alpha, reduces replication of HIV-1 and Mycobacterium tuberculosis in human cells

BackgroundCo-infections of human immunodeficiency virus (HIV) and Mycobacterium tuberculosis (M. Tb) are steadily increasing and represent a major health crisis in many developing countries. Both pathogens individually stimulate tumor necrosis factor-alpha (TNF) release from infected cells and TNF, in turn, enhances the replication of each. A recent report on a Phase I clinical trial suggested that etanercept (soluble TNF receptor) might be beneficial in treating HIV/M. Tb co-infected patients. We sought to determine if a small molecule inhibitor of TNF synthesis and activity could block replication of either organism and thus be a potential adjunct to existing drugs targeting these agents.ResultsLMP-420, a novel anti-inflammatory agent that inhibits TNF, was tested for HIV-1 inhibition both alone and in combination with AZT (3' -azido-3-deoxythymidine). LMP-420 alone was tested against M. Tb. HIV-1 infected human peripheral blood mononuclear cells (PBMC) or M. Tb-infected human alveolar macrophages (AM) were treated with a single dose of LMP-420 and viral or bacterial replication determined after 7 or 5 days respectively. Viral replication was determined from supernatant p24 levels measured by ELISA. M. Tb replication was determined by bacterial culture of macrophage lysates. LMP-420 alone inhibited HIV replication over 7 days with an IC50 of ~300 nM. Combination of LMP-420 with AZT doubled the level of HIV inhibition observed with AZT alone. LMP-420 alone inhibited the replication of virulent M. Tb by >80%, more than that observed with anti-TNF antibody alone.ConclusionInhibition of TNF with inexpensive, small-molecule, orally-active drugs may represent a useful strategy for enhancing the activity of currently-available antiviral and anti-M. Tb agents, particularly in those areas where co-infections with these pathogens act to synergistically enhance each other.

Hepatocyte Transplantation Activates Hepatic Stellate Cells With Beneficial Modulation of Cell Engraftment in the Rat *

We investigated whether transplanted hepatocytes interact with hepatic stellate cells, as cell-cell interactions could modulate their engraftment in the liver. We transplanted Fischer 344 rat hepatocytes into syngeneic dipeptidyl peptidase IV-deficient rats. Activation of hepatic stellate cells was analyzed by changes in gene expression, including desmin and alpha-smooth muscle actin, matrix proteases and their inhibitors, growth factors, and other stellate cell-associated genes with histological methods or polymerase chain reaction. Furthermore, the potential role of hepatic ischemia, Kupffer cells, and cytokine release in hepatic stellate cell activation was investigated. Hepatocyte transplantation activated desmin-positive hepatic stellate cells, as well as Kupffer cells, including in proximity with transplanted cells. Inhibition of Kupffer cells by gadolinium chloride, blockade of tumor necrosis factor alpha (TNF-alpha) activity with etanercept or attenuation of liver ischemia with nitroglycerin did not decrease this hepatic stellate cell perturbation. After cell transplantation, soluble signals capable of activating hepatic stellate cells were rapidly induced, along with early upregulated expression of matrix metalloproteinases-2, -3, -9, -13, -14, and their inhibitors. Moreover, prior depletion of activated hepatic stellate cells with gliotoxin decreased transplanted cell engraftment. In conclusion, cell transplantation activated hepatic stellate cells, which, in turn, contributed to transplanted cell engraftment in the liver. Manipulation of hepatic stellate cells might provide new strategies to improve liver repopulation after enhanced transplanted cell engraftment.

Increases in tumor necrosis factor‐α following transient global cerebral ischemia do not contribute to neuron death in mouse hippocampus

The actions of tumor necrosis factor-alpha (TNF-alpha) produced by resident brain cells and bone marrow-derived cells in brain following a transient global ischemia were evaluated. In wild-type mice (C57Bl/6J) following 20 min ischemia with bilateral common carotid artery occlusion (BCCAo), TNF-alpha mRNA expression levels in the hippocampus were significantly increased at 3 h and 36 h and exhibited a biphasic expression pattern. There were no hippocampal TNF-alpha mRNA expression levels at early time points in either wild-type mice bone marrow transplanted (BMT)-chimeric-TNF-alpha gene-deficient (T/W) or TNF-alpha gene-deficient mice BMT-TNF-alpha gene-deficient mice (T/T), although TNF-alpha mRNA levels were detectable in T/W BMT mice at 36 h. Histopathological findings showed no intergroup differences between wild-type and TNF-alpha gene-deficient mice at 4 and 7 days after transient ischemia. In addition, nuclear factor-kappaB (NF-kappaB) was activated within 12 h after global cerebral ischemia, but electrophoretic mobility shift assays (EMSA) showed no intergroup differences between wild type and TNF-alpha gene-deficient mice. In summary, early hippocampal TNF-alpha mRNA expression may not be related to bone marrow-derived cells, and secondary TNF-alpha expression as early as 36 h after ischemia probably resulted mainly from endogenous brain cells and possibly a few bone marrow-derived cells. Although we cannot exclude the possibility of the TNF-alpha contribution to the physiologic changes of hippocampus after transient global ischemia, these results indicate that TNF-alpha does not influence the morphological changes of the hippocampal neurons under our study condition.

Role of Biological Agents in Immune-mediated Inflammatory Diseases

A new era in the treatment of immune-mediated inflammatory disorders has begun with the clinical availability of anticytokine therapy. Biological agents that are currently available include 3 agents that decrease the activity of tumor necrosis factor-alpha (infliximab, adalimumab, etanercept) and an interleukin-1 receptor antagonist (anakinra), with many more in development. Those extraordinarily effective medications are an important addition to our therapeutic armamentarium, and, although originally developed for rheumatoid arthritis and Crohn disease, have been found to be efficacious in the treatment of seronegative spondyloarthropathies (psoriatic arthritis, ankylosing spondylitis) and juvenile rheumatoid arthritis. Their role is currently being defined in other autoimmune disorders such as uveitis, sarcoidosis, interstitial lung disease, vasculitis, inflammatory myopathies, graft-versus-host disease, and Sjögren syndrome.

Genistein protects dopaminergic neurons by inhibiting microglial activation

Inflammation participates in the pathogenesis and progression of Parkinson's disease, in which microglia play a key role. Inhibition of microglia activation has been shown to attenuate inflammation-mediated dopaminergic neurodegeneration. In this study, we found that genistein, the primary soybean isoflavone, concentration-dependently attenuated the lipopolysaccharide-induced decrease in dopamine uptake and loss of tyrosine hydroxylase-immunoreactive neurons in rat mesencephalic neuron-glia cultures. Genistein also inhibited lipopolysaccharide-induced microglia activation and production of tumor necrosis factor-alpha, nitric oxide and superoxide in mesencephalic neuron-glia cultures and microglia-enriched cultures. Our results indicate that genistein may protect dopaminergic neurons from lipopolysaccharide-induced injury and its effective inhibition of microglia activation may be one of the mechanisms.

Liver Stem Cells: Implications for Hepatocarcinogenesis

Numerous studies point to the fact that liver tumors are derived from single cells (monoclonal), but the important question is, which cell? Stem cell biology and cancer are inextricably linked. In continually renewing tissues such as the intestinal mucosa and epidermis, in which a steady flux of cells occurs from the stem cell zone to the terminally differentiated cells that are imminently to be lost, it is widely accepted that cancer is a disease of stem cells, as these are the only cells that persist in the tissue for a sufficient length of time to acquire the requisite number of genetic changes for neoplastic development. In the liver the identity of the founder cells for the two major primary tumors, hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC), is more problematic. The reason for this is that no such obvious unidirectional flux occurs in the liver, though it is held that the centrilobular hepatocytes may be more differentiated (polyploid) and closer to cell senescence than those cells closest to the portal areas. Moreover the existence of bipotential hepatic progenitor cells (HPCs), along with hepatocytes endowed with longevity and long-term repopulating potential suggests there may be more than one type of carcinogen target cell. Irrespective of which target cell is involved, cell proliferation at the time of carcinogen exposure is pivotal for "fixation" of the genotoxic injury into a heritable form. Taking this view, any proliferative cell in the liver can be susceptible to neoplastic transformation. Thus, hepatocytes are implicated in many instances of HCC, direct injury to the biliary epithelium implicates cholangiocytes in some cases of CC, whereas HPC/oval cell activation accompanies very many instances of liver damage irrespective of etiology, making such cells very likely carcinogen targets. Of course, we must qualify this assertion by stating that many carcinogens are both cytotoxic and cytostatic, and that HPC proliferation may be merely a bystander effect of this toxicity. An indepth discussion of causes of cancer in the liver are beyond the scope of this review, but infectious agents (e.g., hepatitis B and C viruses) play a major role, not just in transactivating or otherwise disrupting cellular proto-oncogenes (hepatitis B virus [HBV]), but in also causing chronic inflammation (hepatitis C virus [HCV] and HBV). Sustained epithelial proliferation in a milieu rich in inflammatory cells, growth factors, and DNA-damaging agents (reactive oxygen and nitrogen species produced to fight infection), will lead to permanent genetic changes in proliferating cells. The upregulation of the transcription factor nuclear factor kappaB (NF-kappaB) in transformed hepatocytes, through the paracrine action of tumor necrosis factor-alpha from neighboring endothelia and inflammatory cells, may be critical for tumor progression given the mitogenic and anti-apoptotic properties of proteins encoded by many of NF-kappaB's target genes.

Chronic hepatitis C virus infection and post-liver transplantation diabetes mellitus

Patients with chronic hepatitis C virus (HCV) infection have a significantly increased prevalence of type 2 diabetes mellitus compared to controls or HBV-infected patients. Moreover, the incidence rate of post-liver transplantation diabetes mellitus (PTDM) also appears to be higher among patients with HCV infection. PTDM is often associated with direct viral infection, autoimmune disorders, and immunosuppressive regimen. Activation of tumor necrosis factor-alpha may be the link between HCV infection and diabetes. In this article, we reviewed the epidemiologic association between HCV infection and PTDM, highlighting the most recent pathophysiologic insights into the mechanisms underlying this association.

Protective effect offufanghuangqiduoganagainst acute liver injury in mice

To study the effects and possible mechanisms of fufanghuangqiduogan (FFHQ) in mice with acute liver injury (ALI). ALI was successfully induced by injecting carbon tetrachloride (CCl4) intraperitoneally and by tail vein injection of Bacillus Calmette Guerin (BCG) and lipopolysaccharide (LPS) in mice, respectively. Each of the two model groups was divided into normal group, model group, FFHQ (60, 120 and 240 mg/kg) treatment groups, and bifendate treatment group. At the end of the experiment, levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), content of malondialdehyde (MDA), activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) in liver homogenate were measured by biochemical methods. The activities of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1) were determined by radio-immunoassay. Hepatic tissue sections were stained with hematoxylin and eosin and examined under a light microscope. In the two models of ALI, FFHQ (60, 120, 240 mg/kg) was found to significantly decrease the serum transaminase (ALT, AST) activities. Meanwhile, FFHQ decreased MDA contents and upregulated the lower SOD and GSH-px levels in liver homogenate. Furthermore, in immunologic liver injury model, FFHQ decreased levels of TNF-alpha and IL-1 in serum. Histologic examination showed that FFHQ could attenuate the area and extent of necrosis, reduce the immigration of inflammatory cells. FFHQ had protective effect on liver injury induced by either CCl4 or BCG+LPS in mice, and its mechanisms were related to free radical scavenging, increasing SOD and GSH-px activities and inhibiting the production of proinflammatory mediators.

TNF-α in the Pleural Fluid for the Differential Diagnosis of Tuberculous and Malignant Effusion

Background : Determining the cause of an exudative pleural effusion is sometimes quite difficult, especially between malignant and tuberculous effusions. Twenty percent of effusions remain undiagnosed even after a complete diagnostic evaluation, including pleural biopsy. The activity of tumor necrosis factor-alpha (TNF-), which is the one of proinflammatory cytokines, is increased in both infectious and malignant effusions. The aim of this study was to investigate the diagnostic efficiency of TNF- activity in distinguishing tuberculous from malignant effusions. Methods : 46 patients (13 with malignant pleural effusion, 33 with tuberculous pleural effusion) with exudative pleurisy were included. TNF- concentrations were measured in the pleural fluid and serum samples using an enzyme-linked immunosorbent assay (ELISA). In addition, TNF- ratio (pleural fluid TNF- : serum TNF-) was calculated. Results : TNF- concentration and TNF- ratio in the pleural fluid were significantly higher in the tuberculous effusions than in the malignant effusions (p in the malignant and tuberculous pleural effusions were similar (p>0.05). The cut off points for the pleural fluid TNF- level and TNF- ratio were found to be 136.4 pg/mL and 6.4, respectively. The sensitivity, specificity and area under the curve were 81%, 80% and 0.82 for the pleural fluid TNF- level (p ratio (p level and TNF- ratio can distinguish a malignant pleural effusion from a tuberculous effusion, and can be additional markers in a differential diagnosis of tuberculous and malignant pleural effusion. The level of TNF- in the pleural fluid could be a more efficient marker than the TNF- ratio.

Inhibitory Effect of Nifedipine on Tumor Necrosis Factor .ALPHA.-Induced Neovascularization in Cultured Choroidal Explants of Streptozotocin-Diabetic Rat

We have previously reported that the Nepsilon (carboxymethyl)lysine (CML) adduct, a major structure of an advanced glycation end product, facilitates proliferation of CD34+ endothelial progenitor cells budded from cultured choroidal explants and produces immature vessel-like structures in fibrin gel. The CML adduct is accumulated and facilitates immature neovascularization in cultured choroidal explants of streptozotocin (STZ)-induced diabetic rat. The CML-enhanced neovascularization activity is associated with the actions of tumor necrosis factor (TNF) alpha, vascular endothelial growth factor and platelet-derived growth factor released from the choroidal explant (Kobayashi et al., Biol. Pharm. Bull., 27, 1382-1387 (2004); 27, 1565-1571 (2004)). The present study was investigated an inhibitory effect of a dihydropyridine calcium antagonist nifedipine on TNF alpha-induced choroidal neovascularization in the STZ-diabetic rat. TNF alpha (1-100 ng/ml) increased neovascularization of cultured choroidal explants in the age-matched normal rat but did not increase it in the diabetic rat. Anti-TNF alpha antibody (1 : 1000) decreased the neovascularization in the diabetic rat but not in the normal rat. Nifedipine (1 microM) inhibited TNF alpha-induced neovascularization of the normal choroidal explant in a non-competitive manner. Nifedipine (1 microM) also inhibited the diabetic state-induced neovascularization and its inhibitory action was reversed by TNF alpha (1-10 ng/ml). In conclusion, STZ-diabetic state facilitated choroidal neovascularization through the release of TNF alpha. Nifedipine inhibited the action of TNF alpha probably by blocking voltage-dependent Ca2+ channels in the endothelial progenitor cells of the diabetic choroid.

Use of porcine tumor necrosis factor receptor 1-Ig fusion protein to prolong xenograft survival.

Delayed rejection of xenografts is a major hurdle that needs to be addressed to achieve long-term engraftment in the pig-to-primate transplant setting. Both vascular and avascular xenografts are susceptible to a delayed rejection process that comprises humoral and cellular responses. Tumor necrosis factor (TNF) is believed to play a role in this process by promoting cell activation, apoptosis and the recruitment of inflammatory cells. To address this problem, we engineered the donor cell in such a way that it could block both human and porcine TNF. We produced a recombinant fusion protein containing the extracellular domain of the porcine TNF-Receptor 1 and an IgG Fc moiety (pTNFR1Ig). We first evaluated by flow cytometry the pTNFR1Ig capacity to prevent TNF alpha-induced expression of SLAI, SLAII, VCAM-1, ICAM-1 and E-selectin on the cell surface of porcine aortic endothelial cells (PAEC). The effect on TNF alpha-mediated cell death was also assessed by propidium iodide staining after incubating PAEC with TNF alpha plus cycloheximide for 24 h. PAEC and porcine fibroblasts were subsequently engineered by retroviral infection to express and secrete pTNFR1Ig and their resistance to the TNF alpha effects was tested in vitro. Finally, we transplanted mock-control and pTNFR1Ig-expressing PAEC under the kidney capsule of BALB/c mice in the absence of immunosuppression and examined the degree of rejection at 2 and 3 weeks post-transplantation. Treatment with pTNFR1Ig resulted in a very potent blockade of human, porcine and murine TNF alpha activity on porcine cells. It inhibited the upregulation of all cell surface markers of activation tested as well as the TNF alpha-mediated cell death. Moreover, pTNFR1Ig-expressing PAEC showed prolonged engraftment in a pig-to-mouse xenotransplant model. Incorporation of strategies that block TNF may prove useful in the development of xenografts resistant to delayed rejection.

Tratamiento de la psoriasis con infliximab

IntroductionPsoriasis and psoriatic arthropathy usually respond to conventional immunosuppressive treatments. Infliximab is a monoclonal chimeric antibody that blocks the activity of tumor necrosis factor-alpha and has proven to be highly effective against resistant psoriasis and psoriatic arthropathy. Presentation of casesTwo males, aged 37 and 58, who suffered from disabling psoriasis and psoriatic arthropathy, were treated with three doses of 5 mg/kg infliximab (weeks 0, 2, 6). The patients maintained their previous medication (25 mg/ week methotrexate, 20 mg/day prednisone and 50 mg/day fentanyl patch in the first case, and 200 mg/day flurbiprofen and 3.5 mg/kg cyclosporine in the second). PASI scores improved by 90 % in both patients in week 10. The psoriatic arthropathy improved in both patients (decrease in BASDAI scores from 7 to 4.2 in case 1 and ACR 50 in case 2). The immunosuppressive medication was able to be suspended in both patients. We did not see any adverse effects during treatment and in the 10 weeks following the end of treatment. ConclusionsInfliximab seems to be an effective and safe drug at the dose of 5 mg/kg in patients with psoriasis and psoriatic arthropathy resistant to conventional immunosuppressive treatments.