Tumor necrosis factor alpha antibody (infliximab) therapy profoundly down-regulates the inflammation in Crohn's ileocolitis

Matrix metalloproteinase-9 and metalloproteinase-2 activity and expression is reduced by melatonin during experimental colitis

Matrix metalloproteinases (MMPs) are associated with matrix turnover in both physiological and pathological conditions. Several data indicate that MMPs play an important role in the pathogenesis of colitis. Various evidence has documented that the pineal secretory product melatonin exerts an important anti-inflammatory effect in different experimental models including colitis. However, no reports are available on the relationship between the activity and expression of MMPs and anti-inflammatory effect of melatonin. The aim of the present study was to evaluate whether melatonin prevents the experimental colitis in rats by regulating MMP-9 and MMP-2 activity and expression. Colitis was induced by intracolonic instillation of dinitrobenzene sulphonic acid (DNBS). Four days after DNBS administration, colon TNF-alpha production was associated with colon damage. Biochemical methods and zymography were used to analyse MMP-9 and MMP-2 activities in colon tissues from DNBS-injured rats. Our studies reveal that melatonin prevented colon injury and lipid peroxidation in rats at 4 days after DNBS-induced colitis. Melatonin also reduced proMMP-9 and MMP-2 activities that were induced in the colon tissues by DNBS administration. Reduced MMP-9 and MMP-2 activities were associated with reduced expression of TNF-alpha. We conclude that melatonin's ability to reduce DNBS-induced colon injury in rats is related to a reduction in proMMP-9 and MMP-2 activities and expression.

Probiotic Lactobacillus reuteri suppress proinflammatory cytokines via c-Jun

BACKGROUND

Differential immunoregulatory capabilities of probiotic Lactobacillus were explored in the context of pediatric Crohn's disease. Experimental strategies addressed molecular mechanisms of tumor necrosis factor (TNF) suppression in activated macrophages by transcriptional regulation.

METHODS

Secreted factors produced by probiotic Lactobacillus reuteri strains were harvested and tested with human monocytes and macrophages. Quantitative immunoassays and real-time reverse-transcriptase polymerase chain reaction (RT-PCR) were used to examine relative quantities of human cytokines and TNF mRNA, respectively, and reporter assays assessed transcriptional regulation of TNF by probiotics. DNA-protein macroarrays interrogated probiotic-mediated effects on transcription factor activation. Finally, enzyme-linked immunosorbent assays (ELISAs) and immunoblots examined the involvement of the specific transcription factor AP-1 and its components.

RESULTS

Probiotic L. reuteri strain ATCC PTA 6475 demonstrated the ability to potently suppress human TNF production by lipopolysaccharide-activated monocytes and primary monocyte-derived macrophages from children with Crohn's disease. Quantities of the chemokine MCP-1/CCL2 were also reduced by probiotic L. reuteri strain ATCC PTA 6475 in macrophages of children in remission. Quantitative real-time RT-PCR and luciferase reporter assays showed that transcriptional regulation of human TNF was a primary mechanism of probiotic-mediated immunomodulation. Probiotic L. reuteri suppressed TNF transcription by inhibiting activation of MAP kinase-regulated c-Jun and the transcription factor, AP-1.

CONCLUSIONS

Human TNF and MCP-1 suppression by probiotic L. reuteri was strain-dependent, and the activation of c-Jun and AP-1 represent primary targets for probiotic-mediated suppression of TNF transcription. This report emphasizes the clonal nature of immunoprobiosis and delineation of a specific immunomodulatory mechanism for probiotic strain selection in future inflammatory bowel disease-oriented clinical trials.

Mucosal macrophages and the regulation of immune responses in the intestine

The healthy intestinal mucosa is home to one of the largest populations of macrophages (mvarphi) in the body [Lee SH, Starkey PM, Gordon S. Quantitative analysis of total macrophage content in adult mouse tissues. Immunochemical studies with monoclonal antibody F4/80. J Exp Med 1985;161:475-89], yet little is known about their function. Resident mvarphi in the large and small intestine are distinct from other mvarphi populations in the body, with regards to both their functional properties and surface phenotype. They respond in an unconventional manner to inflammatory stimuli, with little upregulation of proteins involved in antigen presentation and T cell co-stimulation, and no production of pro-inflammatory cytokines. This suggests that under resting conditions, intestinal mvarphi may be conditioned to be anti-inflammatory in response to local stimuli such as commensal bacteria. In contrast, during inflammation, intestinal mvarphi exhibit increased bactericidal and inflammatory abilities, promote protective immunity and/or mediate pathology. Thus the status of this cell may be the key to understanding how the intestine maintains a balance between being able to generate protective immunity against pathogens, but still prevent pathological inflammation under normal conditions. In this review, we discuss the current knowledge of intestinal mvarphi biology, and highlight the different levels of immunoregulation which influence these cells, with particular focus on innate pathogen recognition receptor (PRR) function and responsiveness to microbial stimuli.

Tumour necrosis factor alpha in segmental colitis associated with diverticula

The pathogenesis of segmental colitis associated with diverticula (SCAD) is unclear, but tumour necrosis factor alpha (TNF-alpha) has been shown to play a pivotal role in the pathogenesis of inflammatory bowel diseases. The aim of this study was to assess TNF-alpha levels in patients with SCAD. In a post hoc analysis of a prospective multicenter study, tissue samples from 13 patients diagnosed with SCAD were subjected to histological analyses. The severity of the inflammation was assessed by means of a histological score and histomorphometry (number of inflammatory cells/mm2). Immunohistochemical staining with an antibody against TNF-alpha was performed on all biopsies and the degree of staining expressed as the percentage of positive stromal cells/1000 counted (TNF-alpha score). Matched patients with irritable bowel syndrome (IBS) were used as controls. Over-expression of TNF-alpha was found in all SCAD patients (38.6 +/- 10.4%), and it was associated with a high histological score (2.5 +/- 0.5) and neutrophil cell count (16.3 +/- 3/mm2). These values were distinctly higher than those found in the IBS controls. Our data suggest that TNF-alpha activity is involved in SCAD pathogenesis, similarly to what occurs in Crohn's disease and ulcerative colitis.

Mechanisms for cytotoxic effects of anti-tumor necrosis factor agents on transmembrane tumor necrosis factor alpha-expressing cells: comparison among infliximab, etanercept, and adalimumab

OBJECTIVE

Three anti-tumor necrosis factor alpha (anti-TNFalpha) agents have been proved to be effective for rheumatoid arthritis (RA) and other inflammatory disorders. Infliximab and adalimumab have been generated as anti-TNFalpha monoclonal antibodies, while etanercept is engineered from human type II TNF receptors. In spite of all 3 agents' equal efficacy for RA, both infliximab and adalimumab are effective for other diseases such as Crohn's disease and Wegener's granulomatosis, while etanercept is not. We undertook this study to understand the different clinical effects of these anti-TNFalpha agents by analyzing their biologic activities on transmembrane TNFalpha.

METHODS

Jurkat T cells stably expressing an uncleavable form of transmembrane TNFalpha were used for the following studies: 1) flow cytometric analysis of binding activities of anti-TNF agents to cell surface transmembrane TNFalpha, 2) complement-dependent cytotoxicity (CDC), 3) antibody-dependent cell-mediated cytotoxicity (ADCC) by using peripheral blood mononuclear cells, and 4) outside-to-inside (reverse) signal transduction through transmembrane TNFalpha estimated by apoptosis and cell cycle analysis using flow cytometry.

RESULTS

All of the anti-TNFalpha agents bound to transmembrane TNFalpha. Infliximab and adalimumab exerted almost equal CDC activities, while etanercept showed considerably lower activity. ADCC activities were almost equal among these 3 agents. Adalimumab and infliximab induced apoptosis and cell cycle arrest in transmembrane TNFalpha-expressing Jurkat T cells, reflecting an outside-to-inside signal transduction through transmembrane TNFalpha.

CONCLUSION

Three different anti-TNF agents showed different biologic effects on transmembrane TNFalpha. This finding suggests that CDC and outside-to-inside signals by anti-TNFalpha antibodies may explain the successful clinical efficacy of adalimumab and infliximab in Crohn's disease and Wegener's granulomatosis.

Cytomegalovirus colitis in a patient with Behcet’s disease receiving tumor necrosis factor alpha inhibitory treatment

Anti-tumor necrosis factor alpha (TNF-α) inhibitors are effective in the treatment of various inflammatory rheumatic conditions. Increased risks of serious infections are the major issues concerning the long-term safety of these agents. We present a case of a young male Behcet’s patient whose disease was complicated by cytomegalovirus (CMV) colitis. Colitis started 10 d after the third Infliximab dose and responded to the cessation of TNF blocking treatment and administration of ganciclovir. Tumor necrosis factor alpha and interferon gamma act at several levels in combating viral infections. CMV infections should be kept in mind and included in the differential diagnosis of severe gastrointestinal symptoms in patients receiving anti-TNF agents.

Parallels between pathogens and gluten peptides in celiac sprue

Pathogens are exogenous agents capable of causing disease in susceptible organisms. In celiac sprue, a disease triggered by partially hydrolyzed gluten peptides in the small intestine, the offending immunotoxins cannot replicate, but otherwise have many hallmarks of classical pathogens. First, dietary gluten and its peptide metabolites are ubiquitous components of the modern diet, yet only a small, genetically susceptible fraction of the human population contracts celiac sprue. Second, immunotoxic gluten peptides have certain unusual structural features that allow them to survive the harsh proteolytic conditions of the gastrointestinal tract and thereby interact extensively with the mucosal lining of the small intestine. Third, they invade across epithelial barriers intact to access the underlying gut-associated lymphoid tissue. Fourth, they possess recognition sequences for selective modification by an endogenous enzyme, transglutaminase 2, allowing for in situ activation to a more immunotoxic form via host subversion. Fifth, they precipitate a T cell–mediated immune reaction comprising both innate and adaptive responses that causes chronic inflammation of the small intestine. Sixth, complete elimination of immunotoxic gluten peptides from the celiac diet results in remission, whereas reintroduction of gluten in the diet causes relapse. Therefore, in analogy with antibiotics, orally administered proteases that reduce the host's exposure to the immunotoxin by accelerating gluten peptide destruction have considerable therapeutic potential. Last but not least, notwithstanding the power of in vitro methods to reconstitute the essence of the immune response to gluten in a celiac patient, animal models for the disease, while elusive, are likely to yield fundamentally new systems-level insights.

Vitamin D derivatives induce apoptosis and downregulate ICAM-1 levels in peripheral blood mononuclear cells of inflammatory bowel disease patients

BACKGROUND

Lymphocytes are crucial in the pathogenesis of inflammatory bowel disease (IBD) and are an important target for drug development. Our aim was to verify whether 2 vitamin D derivatives, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and EB 1089, could induce cell apoptosis and affect cell-cell interaction by regulating adhesion molecule levels.

METHODS

Peripheral blood mononuclear cell (PBMC) proliferation was studied by [3H]thymidine incorporation and apoptosis was determined using an enzyme-linked immunosorbent assay (ELISA) kit. (Poly(ADP-ribose)polymerase (PARP) cleavage, caspase-3, and ICAM-1 protein levels were determined by Western blot analysis.

RESULTS

Our results indicate that 1,25(OH)2D3 or EB 1089 or anti-TNF-alpha (infliximab) induce apoptosis in PBMC obtained from healthy subjects. In IBD patients apoptosis is induced by vitamin D derivatives and by anti-TNF-alpha only in CD patients. Caspase-3 activation and PARP cleavage are registered when PBMC were treated with vitamin D derivatives. ICAM-1 levels remarkably increase when PBMC was incubated with lipopolysaccharide (LPS) or TNF-alpha. The treatment with the vitamin D derivatives, alone or in combination with LPS or TNF-alpha, significantly decreases ICAM-1 levels both in healthy subjects and IBD patients. In HUVEC cocultured with PBMC, previously incubated with LPS or TNF-alpha associated with 1,25(OH)2D3, ICAM-1 levels decrease both in healthy subjects and IBD patients.

CONCLUSIONS

1,25(OH)2D3 and EB 1089 inhibit PBMC proliferation, induce apoptosis in PBMC of healthy subjects and IBD patients, and affect ICAM-1 expression on PBMC and on HUVEC cocultured with PBMC, suggesting that the ICAM-1 downregulation could provide a new target for controlling the recruitment of leukocytes at the sites of inflammation in IBD.

Anti-inflammatory effects of phytosteryl ferulates in colitis induced by dextran sulphate sodium in mice

BACKGROUND AND PURPOSE

We have recently reported that phytosteryl ferulates isolated from rice bran inhibit nuclear factor-kappaB (NF-kappaB) activity in macrophages. In the present study, we investigated the effect of gamma-oryzanol (gamma-ORZ), a mixture of phytosteryl ferulates, cycloartenyl ferulate (CAF), one of the components of gamma-ORZ, and ferulic acid (FA), a possible metabolite of gamma-ORZ in vivo, on a model of colitis in mice.

EXPERIMENTAL APPROACH

We induced colitis with dextran sulphate sodium (DSS) in mice and monitored disease activity index (DAI), histopathology score, tissue myeloperoxidase (MPO) activity, mRNA expressions of cytokines and COX-2, colon length, antioxidant potency and NF-kappaB activity in colitis tissue.

KEY RESULTS

Both DAI and histopathology score revealed that DSS induced a severe mucosal colitis, with a marked increase in the thickness of the muscle layer, distortion and loss of crypts, depletion of goblet cells and infiltration of macrophages, granulocytes and lymphocytes. MPO activity, pro-inflammatory cytokines and COX-2 levels, NF-kappaB p65 nuclear translocation and inhibitory protein of nuclear factor-kappaB-alpha degradation levels were significantly increased in DSS-induced colitis tissues. gamma-ORZ (50 mg kg(-1) day(-1) p.o.) markedly inhibited these inflammatory reactions and CAF had a similar potency. In vitro assay demonstrated that gamma-ORZ and CAF had strong antioxidant effects comparable to those of alpha-tocopherol.

CONCLUSIONS AND IMPLICATIONS

Phytosteryl ferulates could be new potential therapeutic and/or preventive agents for gastrointestinal inflammatory diseases. Their anti-inflammatory effect could be mediated by inhibition of NF-kappaB activity, which was at least partly due to the antioxidant effect of the FA moiety in the structure of phytosteryl ferulates.

Intragastric administration with recombinant Lactococcus lactis producing heme oxygenase-1 prevents lipopolysaccharide-induced endotoxemia in rats

Gut injury is a pivotal initiating event in the dysfunctional inflammatory response that causes postinjury multiple organ failure. Heme oxygenase-1 (HO-1) is an important enzyme that provides cellular protection against oxidative stress in different in vitro and in vivo systems. In this study, we evaluated the protective effects of intragastrically administered live Lactococcus lactis secreting bioactive HO-1 to treat intestinal mucosal injury induced by lipopolysaccharide in rats. Intragastric administration with this recombinant L. lactis strain led to active delivery of HO-1 at the mucosa and significantly decreased morbidity and mortality of lipopolysaccharide -induced endotoxemia as confirmed by blinded macroscopic and microscopic inflammatory scores (Chiu's grade), myeloperoxidase activity, mortality, and tumor necrosis factor-alpha and IL-10 cytokine stimulation. This protective effect could be abolished by an HO-1 inhibitor, the zinc protoporphyrin-IX. Our results suggest that a food-grade bacterium genetically modified to deliver bioactive HO-1 in situ exerts a protective effect against intestinal mucosal injury in rats with endotoxemia via modulation of the immune system. This novel approach may be beneficial for the maintenance of the intestinal barrier and anti-inflammatory response of the lower intestine.

Evaluation of the anti-inflammatory effect of infliximab in a mouse model of acute asthma

BACKGROUND AND OBJECTIVE

To evaluate the potential role of anti-tumour necrosis factor (TNF)-alpha mAb (infliximab) on the inflammatory response in a mouse model of acute asthma.

METHODS

BALB/c mice received intraperitoneal (i.p.) ovalbumin (OVA) on days 0 and 14, 100 microg of OVA intranasally on day 14 and 50 microg of OVA intranasally on days 25, 26 and 27. The low-dose (2.5 mg/kg) and high-dose (6.25 mg/kg) infliximab groups received i.p. infliximab before each i.p. sensitization and on challenge days 1, 6, 13, 20 and 27. The control group received i.p. injections of normal saline with alum on days 0 and 14 and normal saline without alum on days 14, 25, 26 and 27.

RESULTS

There were statistically significant decreases in the numbers of BAL fluid (BALF) neutrophils, eosinophils, as well as lung eosinophils in both the low- and high-dose infliximab groups when compared with the control OVA sensitized/challenged group. The lower dose of infliximab did not alter lung neutrophil counts, but a marked decrease was seen with the high dose of infliximab. After treatment with low and high doses of infliximab, BALF levels of regulated on activation normal T cell expressed and secreted (RANTES), granulocyte macrophage-colony stimulating factor (GM-CSF), TNF-alpha, IL-6, macrophage inflammatory protein (MIP)-2, and levels of RANTES, IL-4, GM-CSF, TNF-alpha, IL-6 and MIP-2 in lung tissue were significantly decreased when compared with the control OVA sensitized/challenged group. There was a significant decrease in BALF IL-4 only in the high-dose infliximab group.

CONCLUSIONS

These results show that an anti-TNF-alpha mAb has a considerable anti-inflammatory effect on allergen-induced lung inflammation in an animal model of acute asthma.

Effect of infliximab on small bowel stenoses in patients with Crohn’s disease

AIM: To assess prospectively small bowel stenoses in Crohn’s disease (CD) patients treated with infliximab using Small Intestine Contrast Ultrasonography (SICUS).

METHODS: Twenty patients (M 12, age, 42.7 ± 11.8 years), 15 of whom showed obstructive symptoms indicating the presence of small bowel stenosis, and 5 without stenosis, were treated with infliximab (5 mg/kg at wk 0, 2, 6 and 5 mg/kg every 8 wk thereafter) for steroid refractoriness, fistulizing disease, or to avoid high-risk surgery. SICUS was performed at the induction phase and at regular time intervals during the follow-up period of 34.7 ± 16.1 mo (range 7-58). Small bowel stenoses were detected by SICUS, endoscopy and MRI.

RESULTS: In no case was progression of stenoses or the appearance of new ones seen. Of the 15 patients with stenosis, 5 stopped treatment after the induction phase (2 for no response, 3 for drug intolerance, one of whom showed complete regression of one stenosis). Among the remaining 10 patients, a complete regression of 8 stenoses (1 stenosis in 5 patients and 3 stenoses in one patient) was observed after 6-22 infliximab infusions.

CONCLUSION: In patients with CD treated with infliximab we observed: (a) No progression of small bowel stenosis and no appearance of new ones, (b) Complete regression of 1/22 stenosis after the induction phase and of 8/15 (53.3%) stenosis after 6-22 infusions during maintenance therapy.

Lidocaine down-regulates nuclear factor-kappaB signalling and inhibits cytokine production and T cell proliferation

Lidocaine is a commonly used local anaesthetic agent which has also been found to possess anti-inflammatory activity in several disorders. However, the mechanism of this effect has been little explored. The aim of this study was to investigate the effect of lidocaine on stimulated human T cells. The effect of lidocaine on Jurkat T cells was examined by enzyme-linked immunosorbent assay (ELISA) to determine secretion of interleukin (IL)-2, and by the [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] viability assay. Tumour necrosis factor (TNF)-alpha and IL-2 mRNA expression was determined by reverse transcription-polymerase chain reaction. In addition, the effect of lidocaine on the proliferation of freshly isolated peripheral blood (PB) CD3(+) T cells was examined by carboxyfluorescein succinimidyl ester dilution. Apoptosis induction and cytokine production and secretion were determined by annexin V/PI assay, intracellular immunostaining and ELISA respectively. The results showed that lidocaine exerts a dose-dependent inhibition of IL-2 and TNF-alpha secretion by Jurkat T cells at the protein and mRNA levels. Moreover, lidocaine reduced nuclear factor-kappaB (NF-kappaB) signalling in clinically relevant concentrations. Similarly, proliferation of anti-CD3 stimulated PB T cells was abrogated significantly by lidocaine, and the percentage of interferon-gamma- and TNF-alpha-producing T cells was diminished after culture with this agent. In both experimental systems, lidocaine's effect was not mediated by cytotoxic mechanism, as no significant apoptosis or necrosis was demonstrated following co-culture of T cells with this drug. In conclusion, lidocaine's anti-inflammatory effect may be mediated by a drug-induced abrogation of T cell proliferation and cytokine secretion independent of cell death. These effects are mediated at least partly by inhibition of NF-kappaB signalling.

A clinical study assessing the tolerability and biological effects of infliximab, a TNF-alpha inhibitor, in patients with advanced cancer

BACKGROUND

Tumour necrosis factor-alpha (TNF-alpha) is an important regulator of the chronic inflammation contributing to tumour progression. Infliximab, an anti-TNF-alpha monoclonal antibody was investigated in this trial of patients with advanced cancer. The primary objectives were to determine the safety profile and biological response of infliximab in a cancer population. Clinical response was a secondary objective.

PATIENTS AND METHODS

Forty-one patients received infliximab at 5 mg/kg (n = 21) or 10 mg/kg (n = 20) i.v. at 0 and 2 weeks and then every 4 weeks. Post-treatment samples were measured for changes in plasma and serum TNF-alpha, CCL2, IL-6 and C-reactive protein (CRP).

RESULTS

Infliximab was well tolerated with no dose-limiting toxic effects. At both doses of infliximab, neutralisation of serum TNF-alpha was observed after 1 h while plasma CCL2, IL-6 and serum CRP were decreased 24 and 48 h following infliximab administration. Seven patients experienced disease stablisation (range 10-50+ weeks). There was no evidence of disease acceleration in any patient.

CONCLUSIONS

Infliximab treatment was safe and well tolerated in patients with advanced cancer. There was evidence of biological activity with baseline TNF-alpha and CCL2 being correlated with infliximab response.

Cell responses regulated by early reorganization of actin cytoskeleton

Microfilaments exist in a dynamic equilibrium between monomeric and polymerized actin and the ratio of monomers to polymeric forms is influenced by a variety of extracellular stimuli. The polymerization, depolymerization and redistribution of actin filaments are modulated by several actin-binding proteins, which are regulated by upstream signalling molecules. Actin cytoskeleton is involved in diverse cellular functions including migration, ion channels activity, secretion, apoptosis and cell survival. In this review we have outlined the role of actin dynamics in representative cell functions induced by the early response to extracellular stimuli.

Anti-TNF antibodies: lessons from the past, roadmap for the future

Tumor necrosis factor alpha (TNF) is an important cell-signaling component of the immune system. Since its discovery over 20 years ago, much has been learned about its functions under normal and disease conditions. Nonclinical studies suggested a role for TNF in chronic immune-mediated inflammatory diseases, such as rheumatoid arthritis, Crohn's disease, and psoriasis, and therefore neutralizing monoclonal antibodies specific to human TNF were developed for clinical evaluation. Treatment with anti-TNF monoclonal antibodies (infliximab, adalimumab, and certolizumab pegol) has been shown to provide substantial benefit to patients through reductions in both localized and systemic expression of markers associated with inflammation. In addition, there are beneficial effects of anti-TNF treatment on markers of bone and cartilage turnover. Further exploration of changes in these markers and their correlation with clinical measures of efficacy will be required to allow accurate prediction of those patients most in need of these treatments. Both the clinical and commercial experience with these anti-TNF antibodies provide a wealth of information regarding their pharmacological effects in humans.

Effect of TNF-alpha inhibition on urinary albumin excretion in experimental diabetic rats

The objective is to assess the effect of TNF-alpha inhibition on urinary albumin excretion in experimental diabetic rats. Male Wistar rats, 8-week-old, were categorized into four groups, which were the control (n = 9), diabetes (n = 9), infliximab-treated diabetes (n = 10), and FR167653-treated diabetes (n = 9) groups. Diabetes was induced by intraperitoneal injection of STZ (40 mg/kg). Thereafter, infliximab was injected intraperitoneally once a month (5.5 mg/kg) and FR167653 was administered orally by mixing with the rat chow (0.08%). The effects of infliximab and FR167653 on urinary albumin excretion were observed for 12 weeks. Body weight, blood sugar, 24-h urinary TNF-alpha, and 24-h urinary albumin/creatinine ratio (Ualb/Ucr) levels were determined at 1, 4, 8, and 12 weeks after the STZ-injection. Treatment of rats with STZ caused a significant loss of body weight, as well as polyuria and hyperglycemia within 1 week, while the urinary excretions of albumin and TNF-alpha were increased. Neither infliximab nor FR167653 affected body weight or blood sugar levels, whereas both decreased urinary albumin excretion, together with a modest decrease in the urinary excretion of TNF-alpha. These results suggest a role of TNF-alpha in the pathogenesis of diabetic nephropathy and show that TNF-alpha inhibition is a potential therapeutic strategy.

Does infliximab influence surgical morbidity of ileal pouch-anal anastomosis in patients with ulcerative colitis?

PURPOSE

Since infliximab has been approved for treatment of patients with refractory ulcerative colitis, surgeons will be increasingly faced with operating on patients who have failed therapy with this potent immunosuppressant. This study was designed to compare short-term complications in patients with ulcerative colitis who were treated with and without infliximab before colectomy.

METHODS

The charts of patients undergoing ileal pouch-anal anastomosis or subtotal colectomy for refractory ulcerative colitis during the five-year period ending October 2005 were reviewed. Postoperative medical and surgical complications were assessed.

RESULTS

Seventeen patients had failed infliximab treatment and 134 patients were never treated with infliximab. Ileal pouch-anal anastomosis was performed in 112 patients (74 percent) and subtotal colectomy in 39 patients (36 percent). There were no deaths. Postoperative complications were observed in 43 patients (28 percent), with no significant difference observed between infliximab-treated (37 percent) and infliximab-untreated patients (27 percent). Of 61 patients (40 percent) treated with preoperative cyclosporine A, 5 patients also had been treated with infliximab. The infliximab and cyclosporine A-treated patient group had an 80 percent complication rate, significantly higher than the 29 percent complication rate noted in the cyclosporine A only-treated group (P = 0.04).

CONCLUSIONS

Although preoperative treatment with infliximab alone does not significantly increase the incidence of postoperative complications, using both inflixiamb and cyclosporine A before colectomy in refractory ulcerative colitis is associated with high surgical morbidity.

Pulmonary actinomycosis complicating infliximab therapy for Crohn's disease

The use of anti-tumour necrosis factor (TNF) agents has expanded significantly over the past few years, particularly for rheumatological diseases and Crohn's disease. A number of associated opportunistic infections have been observed as a result of suppression of T cell-mediated immunity, the most frequent being tuberculosis. We report the first case of pulmonary actinomycosis in a patient receiving regular infusions of infliximab, an anti-TNF agent, for Crohn's disease.

Effect of short-term dietary intake of bovine lactoferrin on intestinal lymphocyte apoptosis in healthy mice

OBJECTIVE

The objective of this study was to describe the effects of short-term dietary exposure of bovine lactoferrin (Lf) on intestinal lymphocyte apoptosis and expression of tumor necrosis factor-alpha (TNF-alpha) in healthy mice.

METHODS

Female C57BL/6 mice were randomly assigned to three treatment groups: 0% Lf (n = 16), 0.2% Lf (n = 16), and 2.0% Lf (n = 15). Bovine Lf was administered orally, as part of the diet, for 4 consecutive days. Intestinal lymphocytes (ILs) were isolated and analyzed for percentages of CD4, CD8, apoptotic CD4, and apoptotic CD8 cells using flow cytometry. Pro- (caspase-3) and anti- (Bcl-2) apoptotic protein expressions and TNF-alpha expression in ILs were determined by Western blotting.

RESULTS

There were significant increases in the percentages of CD4 (P = 0.02) and apoptotic CD4 (P = 0.02) ILs in bovine Lf-fed compared with control mice. Percentages of CD8 and apoptotic CD8 cells and expression of caspase-3 and Bcl-2 in ILs did not differ significantly by diet group. In contrast, the expression of TNF-alpha was significantly lower in Lf-fed versus control mice (P = 0.01).

CONCLUSION

Short-term dietary Lf decreased TNF-alpha expression in ILs and increased apoptosis of CD4 ILs in healthy mice.

Tumour necrosis factor alpha down-regulation parallels inflammatory regression in ulcerative colitis patients treated with infliximab

BACKGROUND

Treatment with the anti-tumour necrosis factor alpha monoclonal antibody infliximab has been shown to be effective in moderate-to-severe ulcerative colitis. However, its effect on the mucosal histopathological abnormalities of this disease is largely unknown. This study aimed to assess the immunohistological effect of infliximab in ulcerative colitis.

METHODS

Nine patients with moderate-to-severe ulcerative colitis received infliximab (5mg/kg) at weeks 0, 2 and 6, respectively. Colonic biopsies were collected before therapy and at week 10, when the Mayo score (including the endoscopic subscore) was also assessed. Severity of inflammation was evaluated by histologic score and histomorphometry. Immunohistochemical staining with antibody against tumour necrosis factor alpha was performed on all biopsies and expressed as percentage of positive stromal cells/1000 counted (tumour necrosis factor alpha score).

RESULTS

A profound down-regulation of mucosal tumour necrosis factor alpha occurred in all the six patients who achieved a clinical response, but not in the three who did not respond. Median tumour necrosis factor alpha score dropped from 44.8 (range 35-58.3) to 12.8 (range 5.3-15.3) in the responders (p=0.03), whilst it remained unchanged in the non-responders. Such effect was related with a dramatic regression of the median histologic score, which dropped from 2.7 (range 2-3) to 0.5 (range 0.0-1.5) in responder patients (p=0.002). This was related to a virtual disappearance of neutrophils in responders (r=0.72; p=0.002; Spearman's test), but not in those who did not improve. Tumour necrosis factor alpha score appeared to be correlated with the histologic, endoscopic and clinical activity.

CONCLUSIONS

A profound tumour necrosis factor alpha down-regulation appears to be strictly associated with a dramatic regression of the inflammation in patients with moderate-to-severe ulcerative colitis treated with infliximab. Such immunohistochemical effect seems to be critical for a clinical and endoscopic response to therapy.

Production of IL-6, in contrast to other cytokines and chemokines, in macrophage innate immune responses: effect of serum and fungal (Blastomyces) challenge

Murine peritoneal macrophages, after adherence and establishment in culture in vitro in the presence of medium containing fetal bovine serum (FBS) for 20 h, then cultured for 20 h, produced several cytokines. If, in the second 20 h period, a fungus (heat-killed Blastomyces, HK-Bd) was introduced, a more complex pattern of cytokine (particularly TNF) and chemokine production ensued. The cytokine production, assayed by antibody array and also quantitation in supernatants, was depressed (particularly TNF) by the addition of mouse serum to these cultures, with the exception of IL-6. Macrophages could be cultured in the presence or absence of serum during the initial 20 h adherence and establishment period, enabling study of the effect of serum factors. In the absence of serum, with or without fungal stimulation, cytokine and chemokine production was more restricted, largely to TNF and IL-6. The addition of mouse serum [corrected] resulted in marked depression of TNF and enhancement of IL-6. The combination of HK-Bd and mouse serum resulted in more IL-6 production than either component alone. The enhancement of IL-6 by mouse serum was concentration-dependent and maximal at 8 h. The effects of fungus or serum on macrophage production of cytokines were similar in an outbred and an inbred mouse strain. The larger repertoire of cytokine production in the macrophages that had been cultured longer (20 h+20 h) in serum may be related to maturation of cell receptors. IL-6 production in vivo in response to fungal-serum complexes could affect pathogenesis by opposing the host defense modulation by proinflammatory cytokines or by modulating the destructive effects of inflammation on host tissues.

Crucial pathophysiological role of CXCR2 in experimental ulcerative colitis in mice

Polymorphonuclear leukocyte infiltration and activation into colonic mucosa are believed to play a pivotal role in mediating tissue damage in human ulcerative colitis (UC). Ligands of human CXC chemokine receptor 1 and 2 (CXCR1/R2) are chemoattractants of PMN, and high levels were found in the mucosa of UC patients. To investigate the pathophysiological role played by CXCR2 in experimental UC, we induced chronic experimental colitis in WT and CXCR2(-/-) mice by two consecutive cycles of 4% dextran sulfate sodium administration in drinking water. In wild-type (WT) mice, the chronic relapsing of DSS-induced colitis was characterized by clinical signs and histopathological findings that closely resemble human disease. CXCR2(-/-) mice failed to show PMN infiltration into the mucosa and, consistently with a key role of PMN in mediating tissue damage in UC, showed limited signs of mucosal damage and reduced clinical symptoms. Our data demonstrate that CXCR2 plays a key pathophysiological role in experimental UC, suggesting that CXCR2 activation may represent a relevant pharmacological target for the design of novel pharmacological treatments in human UC.

Infliximab use in children and adolescents with inflammatory bowel disease

Infliximab is a chimeric monoclonal antibody (75% human, 25% murine) against tumor necrosis factor-alpha, a cytokine with a central role in the pathogenesis of inflammatory bowel disease. Large randomized controlled trials have shown the efficacy and safety of infliximab for the induction and maintenance of remission in adult patients with active Crohn disease (CD). In children and adolescents, mostly small, nonrandomized, non-placebo-controlled studies have supported the notion that infliximab is a potent drug in a population that does not respond to standard therapies. The safety of infliximab is of major concern, and the most frequent severe adverse events are related to severe infections and reactivation of tuberculosis. Non-life-threatening infusion reactions occur rather frequently and seem to be related to the formation of antibodies. The indications for infliximab treatment are therapy-resistant luminal CD (no efficacy or insufficient efficacy of conventional treatment) and therapy-resistant fistulas. An efficient remission induction strategy consists of 3 initial infliximab infusions at 0, 2, and 6 weeks in a dosage of 5 mg/kg to sustain remission. Patients needing maintenance therapy are subsequently treated with an infliximab infusion every 8 weeks. There are indications that the early stages of CD may be more susceptible to immunomodulation, and the natural history of CD may be altered by the introduction of infliximab early in the disease process instead of waiting until conventional therapy has failed. Major points of discussion are whether infliximab maintenance treatment should be episodic (on demand) or scheduled and when infliximab therapy can be discontinued.

Differences in the incidence of flares or new onset of inflammatory bowel diseases in patients with ankylosing spondylitis exposed to therapy with anti-tumor necrosis factor alpha agents

OBJECTIVE

Ankylosing spondylitis (AS) and inflammatory bowel disease (IBD) are clinically and pathologically linked. Anti-tumor necrosis factor (anti-TNF) agents are efficacious in treating AS, but not all are equally effective in treating IBD (Crohn's disease [CD] and ulcerative colitis [UC]). The purpose our study was to analyze the incidence of flares and new onset of IBD in patients with AS treated with anti-TNF agents.

METHODS

Data from 9 trials, 7 placebo-controlled trials and 2 open studies, were analyzed.

RESULTS

Data were available on 419 AS patients exposed to etanercept (625 patient-years), 366 exposed to infliximab (618 patient-years), 295 exposed to adalimumab (132 patient-years), and 434 placebo patients (150 patient-years). A history of IBD was reported in 76 of 1,130 patients (6.7%). There were 2 reports of IBD while receiving placebo (1.3 per 100 patient-years), 1 while receiving infliximab, and 3 while receiving adalimumab. Among the 14 IBD cases receiving etanercept (2.2 per 100 patient-years) there were 8 CD and 6 UC cases, significantly different from infliximab (P = 0.01) but not from placebo. Patients with a history of IBD had an IBD flare odds ratio of 18.0 (95% confidence interval [95% CI] 2-154) while taking etanercept and 4.2 (95% CI 0.4-44) while taking adalimumab, in comparison with infliximab. The incidence rates of new onset of IBD showed no significant difference between etanercept (0.8 per 100 patient-years) and placebo (0.5 per 100 patient-years).

CONCLUSION

New onset and flare of IBD are infrequent events in AS patients receiving anti-TNF therapy. Infliximab (but not etanercept) largely prevents IBD activity. More data are required for adalimumab. The incidence of new onset of IBD was statistically not different from placebo for all anti-TNF agents.

Pneumocystis jiroveci (carinii) pneumonia after infliximab therapy: a review of 84 cases

Anti-tumor necrosis factor-alpha therapy, infliximab, has become an established effective therapy for Crohn's disease and rheumatoid arthritis. However, infliximab has been associated with various opportunistic pathogens such as tuberculosis, histoplasmosis, listeriosis, aspergillosis, and Pneumocystis jiroveci (carinii) pneumonia. We reviewed the FDA Adverse Event Reporting System for cases of Pneumocystis associated with infliximab use from January 1998 through December 2003. The database revealed 84 cases of PCP following infliximab therapy. Concomitant immunosuppressive medications included methotrexate, prednisone, azathioprine, 6-mercaptopurine, and cyclosporine. Mean time between infliximab infusion and onset of symptoms of pneumonia, when reported, was 21 days (+/-18 days; n=40). Twenty-three of the 84 (27%) patients died. The use of infliximab is associated with PCP infection. Further, the mortality rate for Pneumocystis following the use of infliximab is significant. The potential for severe disease, mortality, and often subtle presentation of these infections warrant close follow-up and careful monitoring after therapy.

Infliximab treatment influences the serological expression of matrix metalloproteinase (MMP)-2 and -9 in Crohn's disease

BACKGROUND

Matrix metalloproteinases (MMPs) are actively involved in the pathogenesis of Crohn's disease (CD). We assessed the effect of the anti-tumor necrosis factor-alpha (TNF-alpha) monoclonal antibody infliximab on the in vitro and in vivo expression of MMP-2 and MMP-9 in CD.

METHODS

Infliximab-treated fistulizing (n = 10) or active disease (n = 7) CD patients, from an in-house study, and fistulizing CD patients (n = 42) and active CD patients (n = 24) from 2 placebo controlled studies were evaluated for serum MMP levels and clinical response. Biopsies were evaluated immunohistochemically for the MMPs. Whole blood cultures stimulated with lipopolysaccharide (LPS)/infliximab were evaluated for MMP mRNA and protein levels.

RESULTS

Serum MMP-2 levels in CD patients increased during follow-up, similarly in responders and nonresponders, by infliximab. Immunohistochemistry showed no clear MMP-2 change in biopsies. Serum MMP-9 levels, however, showed a consistent pattern of decrease in most CD patients, particularly in those responding, and MMP-9-positive polymorphonuclear leukocytes in biopsies also decreased by infliximab. LPS stimulation of whole blood increased the MMP-9 levels in plasma significantly in CD patients and controls, but infliximab had no effect on the secretion. Long-term LPS stimulation raised leukocyte MMP-9 mRNA levels 16-fold and infliximab inhibited this induction by 80%.

CONCLUSIONS

Infliximab treatment increases MMP-2 and decreases MMP-9 in serum of patients with CD, the latter also in the intestine, which extends and confirms our previous ex vivo explants observations. However, these changes were not strictly associated with the response to treatment. The enhanced leukocyte MMP-9 expression in CD seems to be regulated by TNF-alpha.

Early changes in rectal nitric oxide and mucosal inflammatory mediators in Crohn's colitis in response to infliximab treatment

BACKGROUND

Treatment with tumor necrosis factor-alpha monoclonal antibody (infliximab) reduces clinical activity and intestinal inflammation in Crohn's disease.

AIM

To study the time-course of the effects of infliximab with reference to mucosal cytokine and inducible nitric oxide synthase expression.

METHODS

Thirty-two patients with Crohn's disease were treated with single dose infliximab (5 mg/kg). Disease activity was assessed days 1, 3, 7 and 28 using Harvey-Bradshaw index. Rectal nitric oxide levels were determined and rectal biopsies collected before treatment, 1 h after infusion and on days 3, 7 and 28. Immunohistochemical staining against inducible nitric oxide synthase, tumor necrosis factor-alpha, interleukin-1beta and interferon-gamma were performed.

RESULTS

Clinical response was seen in 14 patients with down-regulation of global immunohistochemistry expression, reaching nadir day 3. Rectal nitric oxide was increased at baseline (3578 +/- 1199 parts per billion, ppb) compared with controls (89 +/- 13 ppb) (P < 0.001). In patients with clinical response, rectal nitric oxide decreased from 3926 +/- 1687 ppb to 1050 +/- 428 ppb day 28 (P < 0.05).

CONCLUSIONS

Down-regulation of mucosal inflammatory mediators occurs after infliximab. Rectal nitric oxide levels parallel down-regulation of inducible nitric oxide synthase, tumor necrosis factor-alpha, interleukin-1beta and interferon-gamma and may serve as a quantitative biomarker of intestinal inflammation.

Acute inflammation alters bicarbonate transport in mouse ileum

T-cell mediated acute inflammation of the ileum may occur during Crohn's disease exacerbations. During ileal inflammation, absorption of nutrients and electrolytes by villus cells is decreased with a concomitant increase in crypt and/or villus fluid secretion. These alterations lead to fluid accumulation and the subsequent diarrhoea. Net intestinal fluid secretion consists of HCO3--rich plasma-like fluid. However, the regulation and mechanisms of HCO3- secretion in normal and acutely inflamed ileum are not clearly understood. To study this phenomenon, anti-CD3 monoclonal antibody (mAb)- induced in vivo ileal inflammatory mouse models was used for in vitro functional studies with Ussing chamber and pH stat techniques. Three hours after anti-CD3 mAb injection, ileal mucosa stripped of muscular and serosal layers showed a significant increase in short circuit current (Isc) (0.58+/-0.07 microEq h(-1) cm2 versus 1.63+/-0.14 microEq h(-1) cm2). The cAMP-stimulated Isc component was sensitive to glibenclamide but not to DIDS, suggesting that a cystic fibrosis transmembrane conductance regulator (Cftr)-mediated anion conductance was responsible. Basal Cl--dependent HCO3- secretion, measured using a pH stat technique, was decreased significantly in anti-CD3-injected mice, with a simultaneous increase in Cl--independent HCO3- secretion that was also inhibited by glibenclamide. Experiments using Cftr-/- mice showed neither an increase in Isc nor an increase in HCO3- secretion, confirming the role for Cftr protein in stimulating anion secretion following anti-CD3 treatment. Western blot analysis indicated that Cftr protein levels were unaltered by anti-CD3 treatment, at least acutely. Finally, an immunoassay for cAMP showed significant increases in intracellular cAMP in villus cells, but not in crypt cells. These studies therefore suggest a shift from a predominantly electroneutral Cl-HCO3- exchange in normal mice, to a predominantly electrogenic anion secretion including HCO3- that occurs via functional Cftr during anti-CD3-mediated acute inflammation.

Molecular basis of epithelial barrier regulation: from basic mechanisms to clinical application

The intestinal epithelium is faced with the complex task of providing a barrier while also allowing nutrient and water absorption. The frequency with which these processes are disrupted in disease can be taken as evidence of their importance. It is therefore of interest to define the mechanisms of altered intestinal barrier and transport function and develop means to correct disease-associated defects. Over the past 10 years, some of the molecular events underlying physiological epithelial barrier regulation have been described. Remarkably, recent advances have shown that activation of the same mechanisms is central to barrier dysfunction in both in vitro and in vivo models of disease. Although the contribution of barrier dysfunction to pathogenesis of chronic disease remains incompletely understood, it is now clear that cytoskeletal regulation of barrier function is both an important pathogenic process and that targeted inhibition of myosin light chain kinase, which affects this cytoskeleton-dependent tight junction dysfunction, is an attractive candidate for therapeutic intervention.

Risk and prevention of tuberculosis and other serious opportunistic infections associated with the inhibition of tumor necrosis factor

Tumor necrosis factor (TNF) is a proinflammatory cytokine that has a key role in the pathogenesis of a variety of autoimmune diseases-including rheumatoid arthritis-and is an important constituent of the human immune response to infection. At present, three anti-TNF agents are approved (in the US and elsewhere) to treat selected autoimmune diseases: infliximab, etanercept, and adalimumab. These biologic agents have been associated with a variety of serious and 'routine' opportunistic infections; however, differences exist in the mechanisms of action of these agents that might confer variation in their associated risks of infection. From a public-health standpoint, the development of active tuberculosis in some patients who receive anti-TNF therapy is a matter of serious concern. Tuberculosis in such patients frequently presents as extrapulmonary or disseminated disease, and clinicians should be vigilant for tuberculosis in any patient taking anti-TNF therapy who develops fever, weight loss, or cough. To prevent the reactivation of latent tuberculosis infection during anti-TNF therapy, clinicians should screen all patients for tuberculosis, and begin treatment if latent infection is found, before anti-TNF therapy is initiated. Specific tuberculosis screening and treatment strategies vary between geographical regions and are reviewed in this document. The screening strategies employed in Europe and North America have reduced the occurrence of anti-TNF-associated tuberculosis and are clearly to be recommended, but the role of screening in the prevention of other opportunistic (e.g. fungal) infections is far less certain.

Tumor Necrosis Factor Antagonists: Different Kinetics and/or Mechanisms of Action May Explain Differences in the Risk for Developing Granulomatous Infection

OBJECTIVE

Tumor necrosis factor (TNF) antagonists fall into 2 classes:etanercept (ETA) is a soluble TNF receptor, while infliximab (INF) and adalimumab (ADA) are monoclonal antibodies against TNF. All 3 drugs are effective in treating rheumatoid arthritis. However, these agents have been associated with an increased risk of granulomatous infections, such as tuberculosis and histoplasmosis. Several reports indicate that the incidence of granulomatous infections may potentially be higher in individuals treated with INF than ETA.

METHODS

We conducted a comprehensive literature search (1966 to 2004) to review the role of TNF in normal and disease states, and the mechanisms of action of the TNF inhibitors. Specifically, we searched for possible mechanisms for the apparent increase in granulomatous infections associated with TNF inhibitors and for reasons that there may be differences between them.

RESULTS

Infection may result from a number of differences between ETA and INF or ADA. First, binding avidities are different, with ETA binding in a 1:1 ratio and INF/ADA binding in 2 to 3:1 ratios. Second, the clearances of ADA, ETA, and INF are different, being about 13 times higher for ETA than INF or ADA, thus resulting in higher steady-state drug levels for ADA and INF. Also, the methods of administration are different, intravenously (for INF) versus subcutaneously (for ETA and ADA), which results in lower peak concentrations for ETA and ADA, potentially explaining some of the differences in effects on granuloma formation. Third, INF and ADA have somewhat different mechanisms of action from ETA: INF and ADA are associated with antibody-mediated cell lysis, while ETA is not; INF may induce apoptosis in some tissues (eg, gastrointestinal [GI] mucosa) while ETA does not--although this is controversial and may not be true at steady state in synovium, where both drugs seem to cause apoptosis; ETA binds lymphotoxin-alpha while INF does not (ETA may thus be more efficient at preventing granuloma formation by this mechanism than INF); finally, ADA and INF seem to inhibit IFN-gamma expression (probably indirectly), while ETA does not.

CONCLUSIONS

There are significant differences between the 2 classes of TNF antagonists in terms of both their kinetics and mechanisms of action. These differences may help explain the apparent differences in the incidence of granuloma-dependent infections among them.

General principles and pharmacology of biologics in inflammatory bowel disease

The pharmacology of each biologic agent is important regarding the dose required to achieve benefits, duration of therapeutic effect, and the induction of immunogenicity. Comprehension of the individual pharmacology, pharmacodynamics, and pharmacokinetics, in addition to the impact of concomitant immunomodulation on immunogenicity allows optimization of each biologic agent in the appropriate inductive or maintenance setting of IBD.

Apoptosis as a therapeutic tool in IBD?

Defective apoptosis of mucosal cell populations seems to be a relevant pathogenetic mechanism in inflammatory bowel disease (IBD). It has been suggested that the induction of apoptosis in various effector cells may be a relevant therapeutic mechanism in IBD. Indeed, it was shown that different drugs used for treatment of IBD have the capacity to induce apoptosis in T cells or monocytes in vitro and in vivo. However, it remains unclear whether these observations are related to clinical efficacy of these agents. TNF-alpha is one of the most relevant proinflammatory mediators in IBD and anti-TNF treatment has been shown to be of particular benefit for patients with IBD. It could subsequently be shown that various anti-TNF-alpha agents, such as infliximab and adalimumab, can induce apoptosis in activated monocytes and lymphocytes in vitro and in vivo. This mechanism requires reverse signaling via transmembranous TNF, thereby eliciting a signal transduction cascade that results in programmed cell death. Although other mechanisms might also contribute to the clinical effect of anti-TNF-alpha, current data suggest that apoptosis is a relevant mechanism that is associated with clinical efficacy of anti-TNF agents. Induction of apoptosis in activated monocytes or T cells may be regarded as therapeutic tool not only for anti-TNF agents, but also for other drugs used in IBD. Future strategies should focus on identification of mechanisms that prevent apoptosis in the mucosa of patients with IBD and in targeting apoptotic pathways as a therapeutic strategy in IBD.

Melatonin modulates signal transduction pathways and apoptosis in experimental colitis

Various evidences have documented that the pineal secretory product melatonin exerts an important anti-inflammatory effect in different experimental models including colitis. The aim of the present study was to evaluate whether melatonin regulates the inflammatory response of experimental colitis in rats at the level of signal transduction pathway. Colitis was induced by intracolonic instillation of dinitrobenzene sulfonic acid (DNBS). Four days after DNBS administration, a substantial increase of colon TNF-alpha production was associated with the colon damage. In DNBS-treated rats, the colon injury correlated with a significant rise of apoptosis (evaluated by TUNEL coloration) which was associated with a significant increased expression of proapoptotic Bax and decreased colon content of antiapoptotic Bcl-2. This inflammatory response was also related to activation of nuclear factor-kappaB (NF-kappaB) and phosphorylation of c-Jun as well as FAS ligand expression in the colon. Treatment with melatonin (15 mg/kg daily i.p.) was associated with a remarkable amelioration of colonic disrupted architecture as well as a significant reduction of TNF-alpha. Melatonin also reduced the NF-kappaB activation and phosphorylation of c-Jun as well as the Fas ligand expression in the colon. Furthermore, melatonin reduced the expression of Bax and prevented the loss of Bcl-2 proteins as well as the presence of apoptotic cells caused by DNBS. The results of this study show that melatonin administration exerts beneficial effects in inflammatory bowel disease by modulating signal transduction pathways.

[Cytokines in the pathogenesis of inflammatory bowel diseases]

Inflammatory bowel disease (IBD) is produced by an exaggerated response to bacterial flora within the intestinal mucous, in which both environmental and genetic factors are involved. T lymphocytes are involved during the genesis and maintenance of IBD, and their cytokine profile in Crohn's disease (mostly Th1 cytokines) is different from that in ulcerative colitis (mainly Th2 cytokines). After the inflammatory response has been established, the balance between proinflammatory and regulatory cytokines determines the degree of mucosal damage and the form of presentation. A deeper knowledge of the immunological mechanisms involved in IBD has opened new research lines aimed to the development of new therapies such as the neutralization of proinflammatory cytokines with antibodies and the administration of antiinflammatory cytokines, which are currently at different stages of research.

Short- and long-term therapeutic efficacy of nutritional therapy and corticosteroids in paediatric Crohn's disease

BACKGROUND

Comparative data on the therapeutic efficacy of different enteral nutrition formulas and corticosteroids to obtain clinical remission and to induce mucosal healing influencing long-term disease course in paediatric Crohn's disease are still scarce.

AIMS

To investigate the efficacy of nutritional therapy using three different formulas versus corticosteroids to achieve clinical remission as well as to induce intestinal mucosal healing in active Crohn's disease children. Duration of remission and effect on growth recovery were also assessed.

PATIENTS AND METHODS

Clinical, laboratory, endoscopic and histological data of all new diagnosed active Crohn's disease paediatric cases were retrospectively recorded and reviewed. Thirty-seven children (median age 12.1 years) received nutritional therapy (12 polymeric; 13 semi-elemental; 12 elemental diet) and 10 subjects (median age 12.4 years) received corticosteroids.

RESULTS

Similar clinical remission rate were observed after 8 weeks of treatment: 86.5% children receiving nutritional therapy versus 90% treated with corticosteroids. Improvement in mucosal inflammation occurred in 26 out of 37 (64.8%) patients on nutritional therapy and in 4 out of 10 (40%) children on steroids (p < 0.05). Finally, seven subjects on nutritional therapy and none on corticosteroids achieved complete mucosal healing (p < 0.005) at the end of the treatment. Nutritional therapy was more effective than corticosteroids in improving nutritional status and linear growth recovery. Compared to corticosteroids, the duration of clinical remission was longer in the nutritional therapy groups without differences among the three different formulas.

CONCLUSIONS

In children with active Crohn's disease, nutritional therapy is more effective than corticosteroids to improve intestinal inflammation and to maintain a more sustained clinical remission.

Resolution of endothelial activation and down-regulation of Tie2 receptor in psoriatic skin after infliximab therapy

BACKGROUND

Psoriasis is a common dermatosis characterized by erythematous skin plaques and associated arthritis. Microvessels of the papillary dermis in psoriatic lesions are elongated, tortuous, and dilated, which contributes significantly to the proinflammatory response. Angiopoietin (Ang) 1 and 2 and their receptor, Tie2, are a family of growth factors recognized in inflammatory lesions to be critical for new blood vessel growth and maintenance, with recent studies suggesting tumor necrosis factor (TNF)-alpha-induced angiogenesis is in part mediated by the Tie2 receptor. The aim of this study was to evaluate the effect of anti-TNF-alpha therapy on angiogenic growth factor expression and on the cellular infiltrate in psoriatic lesional skin.

METHODS

Sixteen patients with moderate to severe psoriasis and associated psoriatic arthritis (n = 13) received infliximab infusions (3-5 mg/kg) at baseline and at 2 and 6 weeks. Clinical assessments and skin biopsies were undertaken at baseline, and at 2 and 12 weeks. Ang 1, Ang 2, Tie2, and TNF-alpha messenger RNA expression were quantified by real-time polymerase chain reaction. Protein expression of vascular endothelial growth factor, Ang 2, Tie2, TNF-alpha, and the inflammatory infiltrate was determined using immunohistology. We conducted clinical assessments including Psoriasis Area and Severity Index, percentage body surface area, Arthritis Disease Activity Score, and Health Assessment Questionnaire.

RESULTS

At baseline expression of Ang 1/2, vascular endothelial growth factor, Tie2, and TNF-alpha messenger RNA and protein were greater in preinvolved skin compared with uninvolved skin (P < .05). Infliximab produced a significant reduction in protein expression of Ang 2, vascular endothelial growth factor, and Tie2 (P < .001) along with a decrease in messenger RNA expression of Ang 1 (P < .045) and Tie2 (P < .021). This was paralleled by a significant reduction in the inflammatory infiltrate scores (P < .001) and platelet-endothelial cell adhesion molecule (CD31) expression (P = .001), suggesting deactivation of endothelial cell. There was a 93% mean reduction in Psoriasis Area and Severity Index (P = .001), and a significant reduction in Disease Activity Score 28 (P = .012) and mean Health Assessment Questionnaire scores by week 12.

LIMITATIONS

This study involves a small number of patients.

CONCLUSION

These results suggest infliximab is both effective and well tolerated in severe psoriasis, resulting in deactivation of endothelium and down-regulation of growth factor and cytokine expression, leading to a decrease in the cellular infiltrate and clinical improvement in psoriasis. Furthermore, the effect of infliximab on growth factor expression, in particular Tie2, supports previous in vitro work suggesting TNF-alpha may be a major regulator of the Ang/Tie2 pathway.

Inherent potential for production of tumor necrosis factor-alpha by human intestinal macrophages

BACKGROUND AND AIMS

Tumor necrosis factor (TNF) production by the macrophages in intestines appears to play a critical role in the pathogenesis of Crohn's disease (CD). However, it is reported that resident intestinal macrophages (both colonic and small-bowel) do not produce TNF after lipopolysaccharide (LPS) stimulation. It has not yet been proven whether or not intestinal macrophages have an inherent potential to produce TNF. The purpose of this study is to answer this question.

MATERIALS AND METHODS

Colonic macrophages were isolated from lamina propria of human large intestine and stimulated with a variety of substances: LPS, a lipid A derivative (ONO-4007), killed Streptococcus bacterial body (OK-432), phorbol 12-myristate 13-acetate, and lectins (pokeweed mitogen and Sarcophaga lectin).

RESULTS

Colonic macrophages were phenotypically negative for CD14 and positive for CD68 and produced very little TNF in response to LPS, as reported previously. Of the substances tested, only Sarcophaga lectin, which is a defense protein of fleshflies (Sarcophaga peregrina), induced TNF production by the intestinal macrophages. In addition, when the colonic macrophages were cultured on immunoglobulin-A-coated dishes, their characteristic response to LPS was altered, and they produced TNF at a level 6.6 times higher than when on collagen-coated dishes.

CONCLUSION

Colonic macrophages have an inherent ability to produce TNF. Activation of colonic macrophages by unknown substances may contribute to the induction of TNF production, which causes the intestinal inflammation of CD.

Selective effect of infliximab on the inflammatory component of a colonic stricture in Crohn's disease

Although infliximab has been shown to improve the clinical course of Crohn's disease, its effect on intestinal strictures is controversial. We describe the case of a woman with steroid-resistant colonic Crohn's disease presenting with intermittent obstruction because of a tight stricture in the splenic flexure. Compared with uninvolved areas, biopsies showed intense edema and inflammatory cell infiltration and immunohistochemistry revealed an excess of TNF-alpha. Her symptoms responded promptly (CDAI went from 444 to 168) to an infliximab infusion (10 mg kg(-1) BW), which also had a dramatic effect on the stricture, now presenting radiologically as a moderate residual, apparently fibrotic, narrowing of the lumen. Endoscopy and histology confirmed the resolution of inflammation and TNF-alpha virtually disappeared. The patient refused additional infusions and after a few months the disease recurred with features identical to the pre-treatment phase. She then opted for surgery. Histology of the resected strictured colon revealed edema, inflammation, and fibrosis, with TNF-alpha back to pre-treatment levels. This case indicates that, in the colon, infliximab specifically relieves the TNF-alpha-mediated inflammatory component of the stricture while having no effect on fibrosis and suggests that the response to infliximab treatment may depend on the nature of the, stricture itself.

Local injection of infliximab in the postoperative recurrence of Crohn's disease

BACKGROUND

Local injection of infliximab in Crohn's disease (CD) lesions may reduce the risk of rare side effects, reduce the dose, and increase the efficacy of the drug. The objective was to prospectively assess the feasibility and the safety of local injection of infliximab for the postoperative recurrence of patients with CD who were followed for at least 1 year.

METHODS

In a pilot, open-label study, 8 patients with CD (3 men; median age 48 years, range 35-82 years) undergoing ileocolonoscopy were prospectively enrolled. Inclusion criteria included the following: (1) localized (<5 cm) recurrence, (2) inflammatory pattern, and (3) clinically inactive CD. At the first endoscopy, lesions were injected with infliximab (median, 30 mg; range, 8-60 mg); a control endoscopy was performed at 2 weeks in 4 patients (3 received a second injection followed by a control endoscopy at 6 weeks) and at 4 weeks in 4 patients (2 received a second injection followed by a control endoscopy at 8 weeks).

OBSERVATIONS

No patients showed side effects or clinical relapse in the short term and the long term (median follow-up, 20 months; range, 14-21 months). Endoscopic score improved in 3/8 patients. The histologic scores were reduced in 4 patients, worsened in 3, and were unchanged in one patient with CD.

CONCLUSIONS

Local injection of infliximab into patients with CD recurrence is feasible and safe, requiring a low dose. Present findings suggest the need of placebo-controlled trials to assess the efficacy of this new and safe procedure in subgroups of patients with CD.

Review article: Infliximab therapy for inflammatory bowel disease--seven years on

Infliximab, the chimeric monoclonal IgG1 antibody to tumour necrosis factor, is indicated for refractory luminal and fistulizing Crohn's disease and extra-intestinal manifestations of inflammatory bowel disease. Recently, the active ulcerative colitis trials (ACT) studies have shown that infliximab is also efficacious to treat ulcerative colitis resistant to standard therapy. Induction with 5 mg/kg infliximab at weeks 0, 2 and 6 is advocated. The response to infliximab is improved when concomitant immunosuppressive therapy is given. As the majority of patients will relapse if not retreated, a long-term strategy is necessary. Although episodic therapy can be used, the optimal strategy is systematic maintenance treatment with 5 mg/kg intravenous (i.v.) every 8 weeks. Long-term maintenance therapy with infliximab results in a reduction of the rate of complications, hospitalizations and surgeries associated with Crohn's disease. Safety problems with the monoclonal antibody infliximab treatment mainly concern the formation of antibodies to infliximab, which may lead to infusion reactions, loss of response and serum sickness-like delayed infusion reactions. Latent tuberculosis needs to be screened for. The rate of other opportunistic infections is slightly increased mainly in patients treated concomitantly with immunosuppression. There is no evidence that malignancy rates in patients treated with antitumour necrosis factor strategies are increased.

Cyclosporine treatment of anal furunculosis in 26 dogs

OBJECTIVES

To evaluate the effect of cyclosporine on anal furunculosis lesions in 26 dogs.

METHODS

Lesions were graded as mild in 11 dogs, moderate in eight and severe in seven. Each dog was treated with approximately 4 mg/kg cyclosporine orally every 12 hours until the lesions resolved or showed no further improvement. Residual lesions were resected surgically.

RESULTS

Eighteen dogs (69 per cent) experienced complete resolution, seven (27 per cent) improved but had residual lesions and one (4 per cent) showed no improvement. The mean duration of treatment until resolution or no further improvement was 8.8 weeks (range four to 24 weeks). Nine dogs (35 per cent) experienced recurrence. Six were from the group that had shown complete resolution and three were from the group that had surgery. Fifteen dogs (58 per cent) developed side effects to cyclosporine, although none required treatment to be discontinued. Mean duration of follow-up was 6.8 months (range one to 20 months).

CLINICAL SIGNIFICANCE

Cyclosporine was effective at resolving or reducing anal furunculosis lesions in 25 of 26 dogs (96 per cent). However, residual or recurrent lesions remain a potential problem, and surgical resection or long-term cyclosporine treatment may be necessary in some dogs.

Reactivation of latent granulomatous infections by infliximab

Although infliximab and etanercept share tumor necrosis factor (TNF) as a common therapeutic target, accumulating data indicate that infliximab (an anti-TNF monoclonal antibody) poses a greater risk of reactivation of latent granulomatous infections than does etanercept (a soluble TNF receptor). Similarly, infliximab is effective for the treatment of chronic granulomatous inflammatory conditions (e.g., Crohn disease) for which etanercept is ineffective. The ability of infliximab to disrupt established granulomas may be distinct from its ability to neutralize soluble TNF. Further research to elucidate the mechanism of the antigranuloma activity of infliximab is warranted.

Epithelial myosin light chain kinase expression and activity are upregulated in inflammatory bowel disease

The intestinal epithelial barrier is frequently disrupted in inflammatory bowel disease (IBD) and this has been proposed to play a role in disease pathogenesis and reactivation. In vitro studies show that cytokine-induced epithelial barrier dysfunction can be mediated by increased myosin light chain kinase (MLCK) expression and subsequent myosin II regulatory light chain (MLC) phosphorylation. However, this has never been examined in human disease. The aim of these studies, therefore, was to determine whether MLCK is upregulated in the intestinal epithelium of IBD patients. MLCK expression and MLC phosphorylation in human intestinal resection and biopsy specimens were determined by quantitative immunofluorescence microscopy and correlated with clinical and histopathological data. The data show that ileal epithelial MLCK expression was mildly upregulated in inactive IBD. Expression increased further in active disease, with progressive increases in MLCK expression correlating positively with histological disease activity. This correlation between activity and MLCK expression was also seen in individual patients where areas of differing disease activity were analyzed. Colonic epithelial MLCK expression was similarly increased in active IBD and these increases also correlated positively with disease activity, both in individual patients and the overall study group. To evaluate MLCK enzymatic activity, MLC phosphorylation was assessed in snap-frozen colon biopsies. MLC phosphorylation was significantly increased in biopsies with active, but not inactive, IBD. Therefore, these data show that MLCK expression and enzymatic activity are increased in IBD. Moreover, the correlation with disease activity suggests that MLCK upregulation may contribute to barrier dysfunction and IBD pathogenesis.

Treatment with infliximab is associated with increased markers of bone formation in patients with Crohn's disease

OBJECTIVE

Osteoporosis is a common complication of Crohn's disease (CD). Glucocorticoid use and detrimental effects of inflammatory cytokines including tumor necrosis factor-alpha (TNF-alpha) can lead to osteoporosis. The aim of this study was to assess the ability of treatment with the TNF-alpha antagonist infliximab to increase bone formation as measured by surrogate markers of bone turnover in patients with active CD.

METHODS

Sera from 38 prospectively enrolled CD patients were examined for levels of bone alkaline phosphatase (BAP), N-telopeptide of type I collagen (NTX), immunoreactive parathyroid hormone (iPTH), calcium, and pro-inflammatory cytokines at baseline and 4 weeks following infliximab infusion. Crohn's Disease Activity Index (CDAI), Inflammatory Bowel Disease Questionnaire (IBDQ), and glucocorticoid dose also were collected.

RESULTS

In this cohort, CDAI and IBDQ scores were significantly improved at week 4 (P<0.001). Infliximab therapy was associated with an increase in BAP, a marker of bone formation (P=0.010), whereas NTX, a marker of bone resorption, was not increased (P=0.801). Among 22 patients who were taking glucocorticoids, mean glucocorticoid dose decreased 36% (P<0.001; -7.9 mg).

CONCLUSIONS

Treatment with infliximab was associated with increased markers of bone formation (BAP) without increasing bone resorption (NTX). This effect may be due to a beneficial effect of TNF-alpha blockade on bone turnover, a beneficial effect on CD activity resulting in decreased glucocorticoid dose, or both. Studies of longer duration are needed to assess the effect of infliximab on bone mineral density.

Infections associated with tumor necrosis factor-alpha antagonists

Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine involved in a wide range of important physiologic processes. This cytokine has a pathologic role in some diseases, and TNF-alpha antagonists are effective in treating inflammatory conditions. Given the putative role of TNF-alpha in host defense against tuberculosis and other infections, the risk of infection with TNF-alpha antagonists is a concern. Therefore, we searched the literature for reports of tuberculosis and other infections associated with TNF-alpha-antagonist therapy. Although tuberculosis was rarely reported in randomized clinical comparisons of these antagonists, case reports and submissions to the MedWatch program of the United States Food and Drug Administration have been numerous. Most instances were associated with infliximab, but etanercept and adalimumab may also be associated with an increased risk of tuberculosis. Histoplasmosis, listeriosis, aspergillosis, coccidioidomycosis, and candidiasis have been associated with TNF-alpha antagonists, but the causative relationship is not clear. Potential recipients of these drugs should be rigorously screened with skin testing, detailed questioning about recent travel and potential tuberculosis exposure, assessment for symptoms such as cough and weight loss, and chest radiography to minimize their risk of acquiring or reactivating tuberculosis. As with other immunosuppressant drugs, TNF-alpha antagonists should not be given to patients with active infection.

Endoscopic and histologic evidence of persistent mucosal healing and correlation with clinical improvement following sustained infliximab treatment for Crohn's disease

OBJECTIVES

The long-term effect of infliximab on endoscopic and histologic disease activity and expression of inflammatory markers was assessed in Crohn's disease patients who received infliximab as episodic or scheduled maintenance therapy therapy over 54 weeks (ACCENT 1).

METHODS

All patients received Infliximab 5 mg/kg at week 0 and at week 2 were then randomized as responders or nonresponders to placebo or infliximab (5 or 10mg/kg). Patients received placebo or infliximab 5 mg/kg at weeks 2 and 6 followed by placebo or infliximab (5 or 10mg/kg) every 8 weeks or episodically on loss of response. Crohn's Disease Activity Index (CDAI), Crohn's Disease Endoscopic Index of Severity (CDEIS), Inflammatory Bowel Disease Questionnaire (IBDQ), and colonic and ileal Global Histologic Disease Activity (CGHAS and IGHAS) scores were determined at weeks 0, 10, and 54. Tumor necrosis factor-alpha (TNF-alpha), gelatinase B, Infliximab, tenascin, clusters of differentiation marker 68 (CD68), and intercellular adhesion molecule-1 (ICAM-1) were detected in mucosal biopsies by immunohistochemistry.

RESULTS

At baseline, CDEIS significantly correlated with CGHAS only. Further at baseline, both CDEIS and the worst CGHAS or IGHAS, were significantly correlated with CD68, ICAM-1, and gelatinase B expression. At week 10, improvement in CGHAS only, correlated significantly with better CDAI, CDEIS, and IBDQ scores. Improvements in CDEIS and GHAS at week 10 correlated with reductions in gelatinase B and CD68, whereas only GHAS improvement correlated with decreased TNF-alpha expression. At week 54, decreased gelatinase B expression continued to correlate with improved CDEIS and GHAS while decreased CD68 and TNF-alpha expression correlated with GHAS and CDEIS improvement, respectively.

CONCLUSIONS

Endoscopic and histologic evidence of mucosal healing was associated with a sustained reduction in the expression of inflammatory markers. Infliximab-induced improvement in the clinical signs and symptoms of Crohn's disease was associated with endoscopic and histologic evidence of sustained mucosal healing.