Anti-TNF-α antibody allows healing of joint damage in polyarthritic transgenic mice

Anti-tumor-necrosis-factor-α (TNF-α) monoclonal antibody was used to treat Tg197 transgenic mice, which constitutively produce human TNF-α (hTNF-α) and develop a progressive polyarthritic disease. Treatment of both young (7- or 8-week-old) and aged (27- or 28-week-old) mice commenced when at least two limbs showed signs of moderate to severe arthritis. The therapeutic efficacy of anti-TNF-α antibody was assessed using various pathological indicators of disease progression. The clinical severity of arthritis in Tg197 mice was significantly reduced after anti-TNF-α treatment in comparison with saline-treated mice and in comparison with baseline assessments in both young and aged mice. The treatment with anti-TNF-α prevented loss of body weight. Inflammatory pathways as reflected by elevated circulating hTNF-α and local expression of various proinflammatory mediators were all diminished by anti-TNF-α treatment, confirming a critical role of hTNF-α in this model of progressive polyarthritis. More importantly, the amelioration of the disease was associated with reversal of existing structural damage, including synovitis and periosteal bone erosions evident on histology. Repair of cartilage was age dependent: reversal of cartilage degradation after anti-TNF-α treatment was observed in young mice but not in aged mice.     

Attenuation of inflammatory polyarthritis in TNF transgenic mice by diacerein: comparative analysis with dexamethasone,methotrexate and anti-TNF protocols

The impact of diacerein, an effective cartilage targeted therapy that is used in patients with osteoarthritis, on the development and progression of chronic inflammatory arthritis was evaluated in a tumor necrosis factor (TNF) transgenic mouse model (Tg197). The response to diacerein at 2, 20, or 60 mg/kg daily, as well as the comparative effects of other antiarthritis drugs including dexamethasone (0.5 mg/kg daily), methotrexate (1 mg/kg three times weekly) and an anti-TNF agent (5 mg/kg weekly), were assessed in the Tg197 mice. Treatment was initiated before the onset of arthritis and was continued for 5 weeks. A significant improvement in clinical symptoms was found in all three diacerein treated groups in comparison with untreated groups. Confirming these data, semiquantitative histopathologic analysis of the hind paws revealed a significant reduction not only in cartilage destruction but also in the extent of synovitis and bone erosion in diacerein treated groups in comparison with untreated groups. At the most effective dose tested (2 mg/kg daily), diacerein inhibited the onset of arthritis in 28% and attenuated the progression of arthritis in 35% of the Tg197 mice. Comparative analyses showed diacerein to be more potent than methotrexate but not as effective as dexamethasone or anti-TNF agents in suppressing the progression of the TNF mediated arthritis in this model. These results indicate that diacerein has a disease modifying effect on the onset and progression of TNF driven chronic inflammatory arthritis, suggesting that the prophylactic or therapeutic potential of diacerein in patients with RA should be further examined.     

Attenuation of inflammatory polyarthritis in TNF transgenic mice by diacerein: comparative analysis with dexamethasone, methotrexate and anti-TNF protocols

The impact of diacerein, an effective cartilage targeted therapy that is used in patients with osteoarthritis, on the development and progression of chronic inflammatory arthritis was evaluated in a tumor necrosis factor (TNF) transgenic mouse model (Tg197). The response to diacerein at 2, 20, or 60 mg/kg daily, as well as the comparative effects of other antiarthritis drugs including dexamethasone (0.5 mg/kg daily), methotrexate (1 mg/kg three times weekly) and an anti-TNF agent (5 mg/kg weekly), were assessed in the Tg197 mice. Treatment was initiated before the onset of arthritis and was continued for 5 weeks. A significant improvement in clinical symptoms was found in all three diacerein treated groups in comparison with untreated groups. Confirming these data, semiquantitative histopathologic analysis of the hind paws revealed a significant reduction not only in cartilage destruction but also in the extent of synovitis and bone erosion in diacerein treated groups in comparison with untreated groups. At the most effective dose tested (2 mg/kg daily), diacerein inhibited the onset of arthritis in 28% and attenuated the progression of arthritis in 35% of the Tg197 mice. Comparative analyses showed diacerein to be more potent than methotrexate but not as effective as dexamethasone or anti-TNF agents in suppressing the progression of the TNF mediated arthritis in this model. These results indicate that diacerein has a disease modifying effect on the onset and progression of TNF driven chronic inflammatory arthritis, suggesting that the prophylactic or therapeutic potential of diacerein in patients with RA should be further examined.     

IL-1 alpha beta blockade prevents cartilage and bone destruction in murine type II collagen-induced arthritis, whereas TNF-alpha blockade only ameliorates joint inflammation.

Anti-TNF-alpha treatment of rheumatoid arthritis patients markedly suppresses inflammatory disease activity, but so far no tissue-protective effects have been reported. In contrast, blockade of IL-1 in rheumatoid arthritis patients, by an IL-1 receptor antagonist, was only moderately effective in suppressing inflammatory symptoms but appeared to reduce the rate of progression of joint destruction. We therefore used an established collagen II murine arthritis model (collagen-induced arthritis(CIA)) to study effects on joint structures of neutralization of either TNF-alpha or IL-1. Both soluble TNF binding protein and anti-IL-1 treatment ameliorated disease activity when applied shortly after onset of CIA. Serum analysis revealed that early anti-TNF-alpha treatment of CIA did not decrease the process in the cartilage, as indicated by the elevated COMP levels. In contrast, anti-IL-1 treatment of established CIA normalized COMP levels, apparently alleviating the process in the tissue. Histology of knee and ankle joints corroborated the finding and showed that cartilage and joint destruction was significantly decreased after anti-IL-1 treatment but was hardly affected by anti-TNF-alpha treatment. Radiographic analysis of knee and ankle joints revealed that bone erosions were prevented by anti-IL-1 treatment, whereas the anti-TNF-alpha-treated animals exhibited changes comparable to the controls. In line with these findings, metalloproteinase activity, visualized by VDIPEN production, was almost absent throughout the cartilage layers in anti-IL-1-treated animals, whereas massive VDIPEN appearance was found in control and sTNFbp-treated mice. These results indicate that blocking of IL-1 is a cartilage- and bone-protective therapy in destructive arthritis, whereas the TNF-alpha antagonist has little effect on tissue destruction.     

Effect of phospholipase A<Subscript>2</Subscript>inhibitory peptide on inflammatory arthritis in a TNF transgenic mouse model: a time-course ultrastructural study

We evaluated the therapeutic effect of secretory phospholipase A₂ (sPLA₂)-inhibitory peptide at a cellular level on joint erosion, cartilage destruction, and synovitis in the human tumor necrosis factor (TNF) transgenic mouse model of arthritis. Tg197 mice (N = 18) or wild-type (N = 10) mice at 4 weeks of age were given intraperitoneal doses (7.5 mg/kg) of a selective sPLA₂ inhibitory peptide, P-NT.II, or a scrambled P-NT.II (negative control), three times a week for 4 weeks. Untreated Tg197 mice (N = 10) were included as controls. Pathogenesis was monitored weekly for 4 weeks by use of an arthritis score and histologic examinations. Histopathologic analysis revealed a significant reduction after P-NT.II treatment in synovitis, bone erosion, and cartilage destruction in particular. Conspicuous ultrastructural alterations seen in articular chondrocytes (vacuolated cytoplasm and loss of nuclei) and synoviocytes (disintegrating nuclei and vacuoles, synovial adhesions) of untreated or scrambled-P-NT.II-treated Tg197 mice were absent in the P-NT.II-treated Tg197 group. Histologic scoring and ultrastructural evidence suggest that the chondrocyte appears to be the target cell mainly protected by the peptide during arthritis progression in the TNF transgenic mouse model. This is the first time ultrastructural evaluation of this model has been presented. High levels of circulating sPLA₂ detected in untreated Tg197 mice at age 8 weeks of age were reduced to basal levels by the peptide treatment. Attenuation of lipopolysaccharide- and TNF-induced release of prostaglandin E₂ from cultured macrophage cells by P-NT.II suggests that the peptide may influence the prostaglandin-mediated inflammatory response in rheumatoid arthritis by limiting the bioavailability of arachidonic acid through sPLA₂ inhibition.     

Differential effects between marimastat,a TNF-alpha converting enzyme inhibitor,and anti-TNF-alpha antibody on murine models for sepsis and arthritis

We investigated the effects of marimastat, an inhibitor of TNF-alpha converting enzyme and matrix metalloproteinases, and anti-TNF-alpha antibodies on a murine model for sepsis, and on arthritis in human TNF-alpha transgenic mice. Marimastat (25-200 mg/kg) inhibited lipopolysaccharide (LPS)-induced soluble TNF-alpha production in mice in a dose-dependent manner. At an oral dose of 200 mg/kg, marimastat almost completely inhibited LPS-induced soluble TNF-alpha production, but only slightly delayed LPS lethality. On the other hand, anti-TNF-alpha antibodies completely abolished LPS-induced morbidity. In addition, anti-TNF-alpha antibodies, but not marimastat (200 mg/kg/day), inhibited the development of arthritis in human TNF-alpha transgenic mice. These results suggest that cell surface TNF-alpha may be important in the pathogenesis of murine models for sepsis and arthritis.     

Therapeutic antibodies elicited by immunization against TNF-alpha.

Tumor necrosis factor-alpha (TNF-alpha) is critically involved in the pathogenesis of several chronic inflammatory diseases. Monoclonal antibodies against TNF-alpha are currently used for the treatment of rheumatoid arthritis and Crohn's disease. This report describes a simple and effective method for active immunization against self TNF-alpha. This vaccination approach leads to a T-cell-dependent polyclonal and sustainable anti-TNF-alpha autoantibody response that declines upon discontinuation of booster injections. The autoantibodies are elicited by injecting modified recombinant TNF-alpha molecules containing foreign immunodominant T-helper epitopes. In mice immunized with such molecules, the symptoms of experimental cachexia and type II collagen-induced arthritis are ameliorated. These results suggest that vaccination against TNF-alpha may be a useful approach for the treatment of rheumatoid arthritis and other chronic inflammatory diseases.     

Evaluation of TNF-alpha and IL-1 blockade in collagen-induced arthritis and comparison with combined anti-TNF-alpha/anti-CD4 therapy

We have evaluated the effects of anti-TNF-alpha, anti-IL-1, and combined anti-TNF-alpha/anti-CD4 therapy in collagen-induced arthritis. Blockade of TNF-alpha or IL-1 before disease onset delayed, but did not prevent, the induction of arthritis. When treatment was initiated after onset of arthritis, anti-TNF-alpha, anti-IL-1beta, and anti-IL-1R (which blocks IL-1alpha and IL-1beta) were all found to be effective in reducing the severity of arthritis, with anti-IL-1R and anti-IL-1beta showing greater efficacy than anti-TNF-alpha. Anti-IL-1beta was equally as effective as anti-IL-1R, indicating that IL-1beta plays a more prominent role than IL-1alpha in collagen-induced arthritis. An additive effect was observed between anti-TNF-alpha and anti-IL-1R in the prevention of joint erosion and in normalization of the levels of serum amyloid P. Combined anti-TNF-alpha/anti-CD4 therapy also caused normalization of serum amyloid P levels. The therapeutic effect of anti-TNF-alpha plus anti-CD4 was comparable to that of anti-TNF-alpha plus anti-IL-1R, suggesting that combined anti-TNF-alpha/anti-CD4 therapy prevents both TNF-alpha- and IL-1-mediated pathology. Anti-TNF-alpha treatment reduced IL-1beta expression in the joint and, conversely, anti-IL-1beta treatment reduced TNF-alpha expression. Combined anti-TNF-alpha/anti-CD4 treatment almost completely blocked the expression of IL-1beta, thereby confirming the ability of this form of combination therapy to prevent IL-1ss-mediated pathology.     

Emerging role of anti-tumor necrosis factor therapy in rheumatic diseases

Tumor necrosis factor alpha (TNF-alpha) is an inflammatory cytokine that has been implicated in a variety of rheumatic and inflammatory diseases. New understanding of the importance of TNF-alpha in the pathophysiology of rheumatoid arthritis and Crohn's disease led to the development of a new class of targeted anti-TNF therapies. Anti-TNF-alpha agents including etanercept (a fusion protein of the p75 TNF receptor and IgG1) and infliximab (a chimeric monoclonal antibody specific for TNF-alpha) have been approved for the treatment of rheumatoid arthritis. In addition, infliximab has been approved in the treatment of patients with active or fistulating Crohn's disease. A new appreciation of the importance of TNF-alpha in other rheumatic and inflammatory diseases has led to a broadening of the application of anti-TNF agents. Both etanercept and infliximab have been used in open-label and randomized studies in patients with psoriatic arthritis. Although larger randomized trials are needed to confirm early results, both these anti-TNF-alpha agents, etanercept and infliximab, have demonstrated activity in improving the signs and symptoms of psoriatic arthritis and psoriasis. Infliximab has also been shown to be effective in patients with other rheumatic diseases, including ankylosing spondylitis, and may be effective in adult-onset Still's disease, polymyositis, and Beh?et's disease. Further investigations will fully elucidate the role of infliximab in these and other rheumatic diseases.     

Aged wild-type littermates and APPswe+PS1/ΔE9 mice present similar deficits in associative learning and spatial memory independent of amyloid load

APPswe+PS1/ΔE9 transgenic (Tg) mice with Aβ plaque formation in neocortex and hippocampus were evaluated in tests measuring exploratory activity, anxiety, and memory ability using open field test (OFT), Y-maze, contextual fear conditioning (CFC), and Morris water maze (MWM). Wild type (WT) and Tg mice over eight months old showed same locomotion activity and anxiety level in novel stimulation, open field, and Y-maze contexts. In other experiments that measured associative memory and spatial memory in Tg mice and their littermates, the subjects also presented similar deficiencies in memory acquisition. These two aged groups showed abnormal freezing level variance especially in CFC test. In comparison to that in non-transgenic 8-week-old mice group, the acquisition of spatial memory in MWM task was impaired in aged WT and bigenic Tg mice. Taken together, aged wild-type littermates and Tg mice present similar deficits in associative learning and spatial memory independent of amyloid plaques.     

Cytokine production profile in patients with Behcet's disease treated with infliximab

Although the etiology of Behcet's disease (BD) still remains uncertain, various immune abnormalities have been implicated in BD. We studied cytokine production in patients with active and inactive BD, and evaluated the effect of treatment with infliximab (anti-TNF-alpha antibody) on disease activity and cytokine production by the ELISPOT assay. The numbers of cells spontaneously secreting IFN-gamma, IL-12, and TNF-alpha were significantly increased in patients with active BD. Mitogen-stimulated IL-4 secretion was elevated in active patients, though the ratio of IFN-gamma:IL-4 secreting cells was significantly increased in active BD. Next, we monitored cytokine production and expression of IL-12 receptor beta1 chain (IL-12Rbeta1) during short- and long-term infliximab treatment. A single infusion of infliximab significantly reduced the number of PBMC secreting TNF-alpha within 24 h. A rise in TNF-alpha production was associated with clinical deterioration. Infliximab treatment induced a significant increase in the number of cells secreting IFN-gamma and expressing IL-12Rbeta1. A favorable clinical response to infliximab was associated with a persistent reduction in TNF-alpha secretion, but did not correlate with IFN-gamma production. Our findings indicate that TNF-alpha plays a pivotal role in BD, and that anti-TNF-alpha therapy both reduces TNF-alpha production and modulates the functional activity of type 1 cells.     

In vivo neutralization of TNF-alpha promotes humoral autoimmunity by preventing the induction of CTL.

Neutralization of TNF-alpha in humans with rheumatoid arthritis or Crohn's disease has been associated with the development of humoral autoimmunity. To determine the effect of TNF-alpha neutralization on cell-mediated and humoral-mediated responses, we administered anti-TNF-alpha mAb to mice undergoing acute graft-vs-host disease (GVHD) using the parent-into-F(1) model. In vivo neutralization of TNF-alpha blocked the lymphocytopenic features characteristic of acute GVHD and induced a lupus-like chronic GVHD phenotype (lymphoproliferation and autoantibody production). These effects resulted from complete inhibition of detectable antihost CTL activity and required the presence of anti-TNF-alpha mAb for the first 4 days after parental cell transfer, indicating that TNF-alpha plays a critical role in the induction of CTL. Moreover, an in vivo blockade of TNF-alpha preferentially inhibited the production of IFN-gamma and blocked IFN-gamma-dependent up-regulation of Fas; however, cytokines such as IL-10, IL-6, or IL-4 were not inhibited. These results suggest that a therapeutic TNF-alpha blockade may promote humoral autoimmunity by selectively inhibiting the induction of a CTL response that would normally suppress autoreactive B cells.     

TNF-alpha is crucial for the development of mast cell-dependent colitis in mice

Inflammatory bowel disease (IBD) describes chronic inflammatory conditions of the gastrointestinal tract, and TNF-alpha plays a pivotal role in mediating the response. The proinflammatory cytokine TNF-alpha is rapidly released by mast cells after degranulation. In the present study, we hypothesized TNF-alpha to be an important player in our recently described mast cell-dependent murine model for IBD. The effect of neutralizing anti-TNF-alpha MAb was studied on colonic hypersensitivity in mice induced by a skin application of dinitrofluorobenzene (DNFB) followed by an intrarectal challenge with dinitrobenzene sulfonic acid. Features of the colonic hypersensitivity response included diarrhea, mast cell infiltration and activation, infiltration of inflammatory cells in the colon, colonic patch hypertrophy, and increased mast cell-derived TNF-alpha levels in the colon. Anti-TNF-alpha MAb could effectively abrogate diarrhea in DNFB-sensitized mice 72 h after the challenge. The numbers of colonic patches and total tissue damage scores were reduced by anti-TNF-alpha MAb treatment in DNFB-sensitized mice 72 h after the challenge. Mast cell infiltration and activation remained unaffected by neutralizing anti-TNF-alpha MAb. Treatment with the corticosteroid dexamethasone, a frequently used therapeutic treatment in IBD, resulted in a reduction of diarrhea, cellular infiltration, and total tissue damage scores to the same extent as anti-TNF-alpha MAb. Additionally, dexamethasone treatment could also reduce total TNF-alpha levels in the colon, mast cell numbers, and mast cell activation in both vehicle- and DNFB-sensitized mice 72 h after the challenge. These findings suggest that TNF-alpha can play an instrumental role in causing inflammatory responses in the present murine model for IBD downstream from mast cell activation.     

Elevated levels of tumor necrosis factor alpha (TNF-alpha) in human immunodeficiency virus type 1-transgenic mice: prevention of death by antibody to TNF-alpha

Homozygous human immunodeficiency virus type 1 (HIV-1)-transgenic mice (Tg26) appear normal at birth but die within 3 to 4 weeks. The skin of these animals shows diffuse scaling and high-level expression of both HIV-1 mRNA and gp120. Previous experiments showed that treatment with human chorionic gonadatropin (hCG) prevented death and the expression of HIV-1 mRNA and gp120. The present experiments were initiated to study the role of tumor necrosis factor alpha (TNF-alpha) in HIV-1-induced pathology. Examination of the sera of Tg26 mice revealed a 50-fold increase in TNF-alpha levels compared to those in nontransgenic mice. Treatment with antibody to TNF-alpha prevented death, resulted in near normal growth, and produced a marked decrease in skin lesions and a profound reduction in the expression of HIV-1 mRNA and gp120. Both TNF-alpha antibody and hCG reduced TNF-alpha levels in sera by approximately 75%. We conclude that TNF-alpha contributes in a major way to HIV-1-induced pathology in transgenic mice and that both hCG and antibody to TNF-alpha prevent the development of pathology by suppressing the level of TNF-alpha.     

Membrane-associated IL-1 contributes to chronic synovitis and cartilage destruction in human IL-1 alpha transgenic mice

IL-1 molecules are encoded by two distinct genes, IL-1alpha and IL-1beta. Both isoforms possess essentially identical activities and potencies, whereas IL-1alpha, in contrast to IL-1beta, is known to act as a membrane-associated IL-1 (MA-IL-1) and plays an important role in a variety of inflammatory situations. The transgenic (Tg) mouse line (Tg1706), which was generated in our laboratory, overexpresses human IL-1alpha (hIL-1alpha) and exhibits a severe arthritic phenotype characterized by autonomous synovial proliferation with subsequent cartilage destruction. Because the transgene encoded Lys(64) to Ala(271) of the hIL-1alpha amino acid sequence, Tg mice may overproduce MA-IL-1 as well as soluble IL-1alpha. The present study investigated whether MA-IL-1 contributes to synovial proliferation and cartilage destruction in the development of arthritis. Flow cytometric analysis revealed that both macrophage-like and fibroblast-like synoviocytes constitutively produce MA-IL-1. D10 cell proliferation assay revealed MA-IL-1 bioactivity of paraformaldehyde-fixed synoviocytes and the further induction of endogenous mouse MA-IL-1 via autocrine mechanisms. MA-IL-1 expressed on synoviocytes triggered synoviocyte self-proliferation through cell-to-cell (i.e., juxtacrine) interactions and also promoted proteoglycan release from the cartilage matrix in chondrocyte monolayer culture. Interestingly, the severity of arthritis was significantly correlated with MA-IL-1 activity rather than with soluble IL-1alpha activity or concentration of serum hIL-1alpha. Moreover, when the Tg1706 line was compared with the Tg101 line, which selectively overexpresses the 17-kDa mature hIL-1alpha, the severity of arthritis was significantly higher in the Tg1706 line than in the Tg101 line. These results suggest that MA-IL-1 contributes to synoviocyte self-proliferation and subsequent cartilage destruction in inflammatory joint disease such as rheumatoid arthritis.     

Role of endogenous tumor necrosis factor alpha and gamma interferon in resistance to Corynebacterium pseudotuberculosis infection in mice

The production and roles of endogenous tumor necrosis factor alpha (TNF-alpha) and gamma interferon (IFN-gamma) in the infection of Corynebacterium (C.) pseudotuberculosis were investigated in mice. The maximum levels of TNF-alpha and IFN-gamma were detected on day 4 after infection. The administration of anti-TNF-alpha monoclonal antibody (mAb) as well as anti-IFN-gamma mAb increased bacterial proliferation in the organs, leading to the death of infected mice, but anti-IFN-gamma mAb showed a less marked effect than anti-TNF-alpha mAb. The suppressive effect of anti-TNF-alpha and anti-IFN-gamma mAbs on anticorynebacterial resistance was augmented by the simultaneous administration of these antibodies. Anti-TNF-alpha mAb was found to be highly effective when administered on day 0 and day 4, suggesting that TNF-alpha produced during the early stage of infection is critical for the generation of resistance. Histologically, many microabscesses, severe follicular swelling and lymphocyte destruction were observed in mice treated with anti-TNF-alpha or anti-IFN-gamma mAb. Injection of anti-CD4 or anti-CD8 mAb also resulted in significantly increased mortality and a marked suppression of IFN-gamma production, but had no effect on TNF-alpha production. Carrageenan also showed a marked effect on the exacerbation of infection. Taken together, these results suggest that endogenously produced TNF-alpha and IFN-gamma are both essential to the host defense against C. pseudotuberculosis infection and that these cytokines may have an additive effect.     

Apoptosis and reduced influenza A virus specific CD8+ T cells in aging mice

Some studies have reported increased apoptosis in CD8(+) T cells from aged mice. We previously demonstrated diminished virus-specific CD8(+) cytotoxic T lymphocyte (CTL) activity in aged mice in comparison to young mice. The present study investigated the role of apoptosis in age-related influenza virus-specific CD8(+) CTL deficiency. Splenocytes from influenza-primed aged and young mice were stimulated in vitro with virus. The CD8(+) T cell/total lymphocyte ratios correlated with CTL activity and were significantly decreased and increased in aged and young mice, respectively. Fas, FasL, TNF-alpha and TNFR-p55 expression, measured by flow cytometry, ELISA and/or RT-PCR, were significantly elevated in aged mice. Apoptotic CD8(+) T cells (Annexin V binding) were also elevated in aged mice. IL-12 treatment increased CD8(+) CTL activity and IFN-gamma production but did not affect apoptosis. Thus, apoptosis may contribute to reduced influenza virus-specific CD8(+) T cell frequency, CTL deficiency and increased influenza disease in aging.     

Effect of a matrix metalloproteinase inhibitor on host resistance against Listeria monocytogenes infection

Hydroxy acid-based matrix metalloproteinase (MMP) inhibitors have been shown to inhibit tumor infiltration and growth, endotoxin shock, and acute graft-versus-host disease. Blockade of the release of soluble tumor necrosis factor-alpha (TNF-alpha) and CD95 ligand (CD95L; FasL) from cell-associated forms is reportedly involved in the mechanism of the drug effect. We investigated the effect of a MMP inhibitor, KB-R7785, on host resistance against Listeria monocytogenes infection, in which TNF-alpha is essentially required for the defense, in mice. The administration of KB-R7785 exacerbated listeriosis, while the drug prevented lethal shock induced by lipopolysaccharide and D-galactosamine. KB-R7785 inhibited soluble TNF-alpha production in spleen cell cultures stimulated by heat-killed L. monocytogenes and the drug treatment reduced serum TNF-alpha levels in infected mice, whereas the compound was ineffective on the modulation of interferon-gamma and interleukin-10 production. The effect of KB-R7785 was considered to be dependent on TNF-alpha because the drug failed to affect L. monocytogenes infection in anti-TNF-alpha monoclonal antibody-treated mice and TNF-alpha knockout mice. Anti-CD95L monoclonal antibody was also ineffective on the infection. These results suggest that induction of infectious diseases, to which TNF-alpha is critical in host resistance, should be considered in MMP inhibitor-treated hosts.     

Reduction of experimental necrotizing enterocolitis with anti-TNF-alpha

Necrotizing enterocolitis (NEC) is the most common gastrointestinal disease of premature infants. However, despite significant morbidity and mortality, the etiology and pathogenesis of NEC are poorly understood. Evidence suggests that ileal proinflammatory mediators such as IL-18 contribute to the pathology associated with this disease. In addition, we have previously shown that upregulation of TNF-alpha in the liver is correlated with ileal disease severity in a neonatal rat model of NEC. With the use of a neonatal rat model of NEC, we evaluated the incidence and severity of ileal damage along with the production of both hepatic and ileal proinflammatory cytokines in animals injected with (anti-TNF-alpha; n = 23) or without (NEC; n = 25) a monoclonal anti-TNF-alpha antibody. In addition, we assessed changes in apoptosis and ileal permeability in the NEC and anti-TNF-alpha groups. Ileal damage was significantly decreased, and the incidence of NEC was reduced from 80% to 17% in animals receiving anti-TNF-alpha. Hepatic TNF-alpha and hepatic and ileal IL-18 were significantly decreased in pups given anti-TNF-alpha compared with those sham injected. In addition, ileal luminal levels of both TNF-alpha and IL-18 were significantly decreased in the anti-TNF-alpha-injected group. Ileal paracellular permeability and the proapoptotic markers Bax and cleaved caspase-3 were significantly decreased in the anti-TNF-alpha group. These data show that hepatic TNF-alpha is an important component for the development of NEC in the neonatal rat model and suggest that anti-TNF-alpha could be used as a potential therapy for human NEC.