Optimizing anti-TNF treatment in inflammatory bowel disease

CT Enteroclysis

Computed tomographic (CT) enteroclysis is a hybrid technique that combines the methods of fluoroscopic intubation-infusion small-bowel examinations with that of abdominal CT. The use of multidetector CT technology has made this a versatile examination that has evolved into two distinct technical modifications. CT enteroclysis can be performed by using positive enteral contrast material without intravenous contrast material and neutral enteral contrast material with intravenous contrast material. CT enteroclysis has been shown to be superior to other imaging tests such as peroral small-bowel examinations, conventional CT, and barium enteroclysis, except in the demonstration of early apthous ulcers of Crohn disease. CT enteroclysis is complementary to capsule endoscopy in the elective investigation of small-bowel disease, with a specific role in the investigation of Crohn disease, small-bowel obstruction, and unexplained gastrointestinal bleeding.

Intravenous iron therapy restores functional iron deficiency induced by infliximab

BACKGROUND AND AIMS

Infliximab (IFX) and iron sucrose (FeS) are of high value in inflammatory bowel disease (IBD). We aimed to assess the relative role of both therapies in IBD related anaemia and their safety when used in combination.

METHODS

IBD patients with anaemia receiving a first series of FeS infusions in addition to IFX were prospectively followed. We investigated serum kinetics of erythropoietin (EPO), soluble transferrin receptors (sTFRs) and vascular endothelial growth factor (VEGF).

RESULTS

Data analysis included 87 patients of whom 49.4% achieved the target Hb level of 12.0 g/dL. IFX resulted in a significant increase of EPO and sTFR compared to baseline pre-IFX levels (p=0.029 and p=0.005 respectively) and after a 12-week combined FeS and IFX treatment, EPO and sTFR levels dropped significantly compared to pre-FeS levels (p<0.001 for both). Infusion related adverse events were recorded in 2 IFX treated patients (2.3%, 0.7% of the infusions) and were mild. Disease activity and quality of life were not affected.

CONCLUSIONS

In anaemic IBD patients treated with IFX, combined administration of FeS is safe. Infliximab significantly increases serum EPO and sTFR levels resulting in an increased functional iron deficiency, which is restored after combined treatment with I.V. iron sucrose.

Clinical pharmacokinetics and use of infliximab

Tumor necrosis factor-alpha (TNFalpha) is a key proinflammatory cytokine involved in chronic inflammatory diseases. Infliximab, a chimeric (human-murine) monoclonal IgG1 anti-TNFalpha antibody, is used in the treatment of Crohn's disease (including fistulising disease) and rheumatoid arthritis (in combination with methotrexate) if standard treatments have failed. The indications for infliximab have recently been expanded to include ankylosing spondylitis, psoriatic arthritis, psoriasis and ulcerative colitis. The biological agent infliximab is given by multiple intravenous infusions in a dosage of 3-5 mg/kg (initially at weeks 0, 2 and 6; subsequently in intervals of 4-8 weeks). In controlled trials, clinical response rates of 20-40% have been achieved with such regimens in Crohn's disease and rheumatoid arthritis. However, the therapeutic benefits must be balanced against the risks of a variety of severe adverse events (e.g. severe infections including tuberculosis, hepatotoxicity, infusion reactions, serum sickness-like disease and lymphoma). Following single and multiple infusions of infliximab, no relevant differences in median concentration-time profiles have been observed between patients with Crohn's disease, patients with rheumatoid arthritis and patients with psoriasis. The apparent volume of distribution of the high-molecular-weight infliximab (149.1 kDa) is low (3-6L) and represents the intravascular space. The long persistence in this compartment (elimination half-life 7-12 days, mean residence time 12-17 days) is due to the very low systemic clearance of about 11-15 mL/hour (0.18-0.25 mL/minute). Elimination of infliximab is most probably accomplished through degradation by unspecific proteases. During multiple infusions (every 4-8 weeks), no accumulation was observed, and serum concentrations and the area under the plasma concentration-time curve of infliximab increased in proportion to the infused dose, indicating linear pharmacokinetics. Co-medication with methotrexate delayed the decline in the serum concentrations of infliximab. When relating serum concentrations to the clinical response in patients with rheumatoid arthritis and patients with Crohn's disease, it can be assumed that trough concentrations above 1 microg/mL could be used as a kind of therapeutic target. In the future, identification of biomarkers for (non-)response and risk factors for adverse drug reactions would be very helpful. Furthermore, combined biological, pharmacokinetic, pharmacogenomic and clinical studies have not yet been performed and are needed to optimise the therapeutic potential of infliximab, which is currently established as a rescue treatment in refractory patients.

Current and future therapies for inflammatory bowel disease

The introduction of biologic agents to the therapeutic arsenal has dramatically impacted the way we treat patients with inflammatory bowel disease, allowing clinicians to achieve lasting remission in patients who are unresponsive to conventional therapies. New research continues to expand our understanding of the inflammatory cascade of ulcerative colitis and Crohn's disease, revealing a host of potential therapeutic targets for intervention. As we look toward the future in this rapidly developing field, we must learn how best to incorporate these new agents into the treatment algorithm to enhance or replace conventional therapies.

Blockage of tumor necrosis factor prevents intestinal mucosal inflammation through down-regulation of interleukin-23 secretion

Tumor necrosis factor (TNF) plays an important part in the pathogenesis of several inflammatory diseases. Its expression is highly increased in inflamed mucosa of inflammatory bowel disease, and anti-TNF treatment appears to improve mucosal inflammation in these patients. However, the role of TNF in the pathogenesis remains to be investigated. In the present study, an experimental colitis was induced by transfer of syngeneic CD45RB(high)CD4(+) T cells into SCID mice. Quantitative analysis of interleukin (IL)-23p19 and IL-17 mRNA was demonstrated to be markedly increased in inflamed colon 4 and 8 weeks after CD45RB(high)CD4(+) T-cell transfer. These SCID recipients were treated i.p. with anti-TNF mAb starting at the beginning (early treatment) or 4 weeks (delayed treatment) after T-cell transfer to investigate the in vivo relevance of TNF to the pathogenesis. The results demonstrated that early treatment with anti-TNF effectively prevented intestinal mucosal inflammation, as evidenced by gradual increase of body weight and absence of diarrhea. Anti-TNF significantly suppressed leukocyte infiltration in the inflamed colon, and down-regulated IFN-gamma, IL-2 and TNF secretion by lamina propria CD4(+) T cells. Interestingly, anti-TNF also significantly decreased expression of IL-23p19 and IL-17 in inflamed colon. Moreover, delayed anti-TNF treatment demonstrated to markedly improve mucosal inflammation. The data suggest that administration of anti-TNF reverses mucosal inflammation via down-regulated pro-inflammatory cytokines, particularly IL-23p19 and IL-17, and decreased leukocyte infiltration in the bowel, thus providing additional relevance of target therapy against TNF.

Immunologic and molecular mechanisms in inflammatory bowel disease

Molecular and immunologic mechanisms underlying inflammation in inflammatory bowel disease (IBD) are largely unknown. Recent studies have helped better characterize genetic and environmental factors associated with colitis. Discoveries of genetic variants have confirmed that IBD is a bacteria and cytokine-driven pathologic immune response. Data have demonstrated that certain T cell subsets are important in executing the inflammatory cascade. Insufficient regulatory cell activity or modulatory cytokine production results in unrestrained inflammation. Biologic agents that block inflammatory cytokines (anti-TNFalpha antibodies) have been used successfully to treat IBD. Recent advances have also identified mucosal regulatory pathways.

Diagnosis and management of inflammatory bowel disease in children

Upwards of 100,000 children and adolescents are affected by inflammatory bowel disease (IBD) in the United States, and the incidence of IBD appears to be increasing worldwide. Although the diagnosis and differentiation of Crohn's disease or ulcerative colitis is still based on clinical, radiographic, endoscopic, and histological findings, newer less invasive serological tests are being employed to help distinguish these disorders and provide prognostic information to possibly guide therapy. Videocapsule endoscopy has increased our ability to detect previously unrecognized small bowel inflammation in selected patients. Whereas initial therapy has historically included aminosalicylates and corticosteroids, recent data suggest the limited efficacy of aminosalicylates in Crohn's disease and the high likelihood or corticosteroid dependence in patients with either Crohn's disease or ulcerative colitis. The early use of immunomodulators has become standard-of-care in both disorders and has decreased corticosteroid dependence. The advent of biologic therapy, primarily with infliximab, has dramatically improved short-term outcomes in both Crohn's disease and ulcerative colitis. Longer-term data on whether infliximab changes the natural history of these disorders (eg, requirement for surgery) awaits further study. As more aggressive therapy is being increasingly employed, rare complications such as lymphoma or opportunistic infection have developed.

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.

[Medical therapy of inflammatory bowel diseases: Crohn's disease]

The therapy of inflammatory bowel diseases is based on 5-aminosalicylates (5-ASAs) that are the forefront of treatment of mild-to-moderate active disease and maintenance; steroids are used for the treatment of moderate-to-severe active disease; immunosuppressives and sometimes antibiotics in moderate-to-severe disease; maintenance and for the treatment of selected complications. The last few years have witnessed a significant change in the treatment of Crohn's disease. Based on evidence from new clinical studies and recent meta-analyses, the role of and indications for conventional therapy have been reassessed. The 5-ASAs are nowadays less frequently used in both active disease and maintenance therapy. Instead, budesonide has been introduced in the treatment of mild-to-moderate ileal disease. Besides the modest use of 5-ASAs, steroids are prescribed for active colonic disease. Immunosuppressives, especially azathioprine, are more commonly used in moderate-to-severe disease as well as in maintenance. The preferred maintenance regimen following medically- and surgically-induced remission, in addition to relationship between medical and surgical therapies, has also changed. The recent introduction of new "biological" therapy represents a major, promising change in the therapy of resistant and penetrating disease.

Safety of biologic therapy

Several biologic agents have been assessed in patients with inflammatory bowel disease (IBD; Crohn's disease [CD] and ulcerative colitis [UC]). Until recently, only infliximab (humanized monoclonal anti-TNF-alpha antibody) had been approved by the Food and Drug Administration (FDA) to induce and maintain remission in patients with active mild to moderate and/or fistulizing Crohn's disease who are refractory to conventional therapy. Two recent trials, ACT 1 and ACT2, observed high efficacy of infliximab in inducing and maintaining clinical remission, mucosal healing, and corticosteroid-sparing effects in patients with moderate to severe UC. This agent also was recently approved by the FDA for the treatment of ulcerative colitis to reduce signs and symptoms, to induce clinical remission and healing of the intestinal mucosa, and to eliminate the use of corticosteroids in patients with moderately to severely active UC who have had an inadequate response to conventional therapy. There have been many randomized, double-blind, controlled and open-label uncontrolled studies of large and small numbers of patients assessing the efficacy and safety of various biologic agents considered potentially useful in the treatment of IBD. Among all the biologic agents, infliximab has the most robust data on safety. This is because it has been evaluated in many more trials than has any other biologic agent. In addition, postmarketing experience provides very valuable information about adverse events occurring during treatment with this agent.

Infliximab in the treatment of Crohn's disease

The recent introduction of infliximab, a chimeric monoclonal antibody against tumor necrosis factor-alpha, has greatly modified the treatment of Crohn's disease (CD). Data from the literature show encouraging results after intravenous infusion both for closure of intestinal or perianal fistulas and for induction and maintenance of remission in patients with moderate to severe intestinal disease unresponsive to other treatments. However, some contraindications such as fibrostenosing CD and sepsis have been identified. In addition, the data on long-term outcomes and safety is still limited. Our initial experience showed that in selected cases local injection of infliximab is effective in the treatment of complex perianal disease offering the possibility of using such treatment even in small bowel obstructing disease with minimal systemic effects. This paper analyzes the state of the use of both intravenous and local injection of infliximab in patients with CD.

Patient preferences between surgical and medical treatment in Crohn's disease

PURPOSE

Crohn's disease poses difficult choices in which the most appropriate treatment option is not always obvious. When this state of uncertainty exists, patients' preferences should have an increasingly important part of clinical decision making. The purpose of this study was to compare patients' preferences for surgical intervention in Crohn's disease with the preferences of surgeons and gastroenterologists.

METHODS

Outpatients with Crohn's disease were interviewed to quantify their preferences for six scenarios by using the prospective preference measure. An identical questionnaire was mailed to all Australian and New Zealand colorectal surgeons and a random sample of 300 Australian gastroenterologists.

RESULTS

Forty-one of 123 patients with Crohn's disease (33 percent), 92 of 127 colorectal surgeons (72 percent), and 74 of 272 gastroenterologists (27 percent) participated. There were significant differences between patients and gastroenterologists for three of six scenarios and between surgeons and gastroenterologists in four of six scenarios. Seventy-six percent of gastroenterologists were willing to gamble to avoid an ileocolic resection compared with 37 percent of surgeons (chi-squared = 25.44; P < 0.0001) and 39 percent of patients (chi-squared = 15.44; P < 0.001).

CONCLUSIONS

Patients and clinicians were able to trade and gamble life expectancy as a measure of preference for varying hypothetical surgical treatments, even though these treatment options impacted on quality of life rather than survival. Patients' preferences did not align with clinicians. For most scenarios, colorectal surgeons' preferences were significantly different to those of gastroenterologists.

Quercetin inhibits TNF-induced NF-kappaB transcription factor recruitment to proinflammatory gene promoters in murine intestinal epithelial cells

Flavonoids may play an important role for adjunct nutritional therapy of chronic intestinal inflammation. In this study, we characterized the molecular mechanisms by which quercetin and its enteric bacterial metabolites, taxifolin, alphitonin, and 3, 4-dihydroxy-phenylacetic acid, inhibit tumor necrosis factor alpha (TNF)-induced proinflammatory gene expression in the murine small intestinal epithelial cell (IEC) line Mode-K as well as in heterozygous TNFDeltaARE/WT mice, a murine model of experimental ileitis. Quercetin inhibited TNF-induced interferon-gamma-inducible protein 10 (IP-10) and macrophage inflammatory protein 2 (MIP-2) gene expression in Mode-K cells with effective inhibitory concentration of 40 and 44 micromol/L, respectively. Interestingly, taxifolin, alphitonin, and 3,4-dihydroxy-phenylacetic acid did not inhibit TNF responses in IEC, suggesting that microbial transformation of quercetin completely abolished its anti-inflammatory effect. At the molecular level, quercetin inhibited Akt phosphorylation but did not inhibit TNF-induced RelA/I-kappaB phosphorylation and IkappaB degradation or TNF-alpha-induced nuclear factor-kappaB transcriptional activity. Most important for understanding the mechanism involved, chromatin immunoprecipitation analysis revealed inhibitory effects of quercetin on phospho-RelA recruitment to the IP-10 and MIP-2 gene promoters. In addition, and consistent with the lack of cAMP response element binding protein (CBP)/p300 recruitment and phosphorylation/acetylation of histone 3 at the promoter binding site, quercetin inhibited histone acetyl transferase activity. The oral application of quercetin to heterozygous TNFDeltaARE/WT mice [10 mg/(d x kg body wt)] significantly inhibited IP-10 and MIP-2 gene expression in primary ileal epithelial cells but did not affect tissue pathology. These studies support an anti-inflammatory effect of quercetin in epithelial cells through mechanisms that inhibit cofactor recruitment at the chromatin of proinflammatory genes.

Immune dysfunction in inflammatory bowel disease

Ulcerative colitis (UC) and Crohn's disease (CD) are idiopathic inflammatory bowel diseases (IBDs) that are characterized by chronic periods of exacerbation and remission. Research into the immunopathogenesis of IBD adds support to the theory that the disease results from a dysfunctional regulation of the immune system that leads to the polarization of intestinal immune cells toward a Th1 (T helper) response. The immunologic factors that mediate alterations in intestinal homeostasis and the development of intestinal mucosal inflammation have been at the forefront of IBD research. Cytokines, which are important regulators of leukocyte trafficking and apoptotic cell death, have emerged as essential immune molecules in the pathogenesis of IBD. In this study, recent advances in the understanding of the dynamism of cytokines and the consequences for mucosal immunity and inflammation in IBD are discussed. Furthermore, this study highlights the potential use of cytokines, anti-cytokine antibodies, and cytokine-related biologic therapies as novel targets for the treatment of IBD.

Short- and long-term response to and weaning from infliximab therapy in pediatric ulcerative colitis

OBJECTIVES

We evaluated the response to infliximab in pediatric patients with ulcerative colitis (UC) and their long-term follow-up. We expanded our previous study of 14 patients and furthermore evaluated the success of weaning patients from infliximab.

PATIENTS AND METHODS

We reviewed the charts of 27 pediatric patients with UC who were treated with infliximab instead of undergoing a colectomy. Patients with new-onset UC refractory to intravenous steroids for 5 to 10 days and patients with non-steroid-dependent UC with an acute exacerbation were classified as acutely ill (n = 16); patients with chronic steroid-dependent UC were classified as chronically ill (n = 11). The Lichtiger Colitis Activity Index (LCAI) was measured for all patients at baseline and at 1 and 2 months after treatment with infliximab was initiated. Patients were regarded as successfully treated if they remained off steroids and avoided colectomy.

RESULTS

The acutely ill group had a mean LCAI score of 11.4 at induction and 0.3 after 2 months. The chronically ill group had a mean LCAI score of 11.2 at induction and 5.5 after 2 months. Treatment with infliximab was successful in 75% of acutely ill patients and in 27% of chronically ill patients. Infliximab was discontinued in 80% of successfully treated patients (83% of acutely ill, 67% of chronically ill). These patients had an average of 10 infusions and a mean follow-up time of 10 months from their last infliximab infusion.

CONCLUSIONS

Our results suggest that infliximab is more effective in acutely ill UC patients than in patients with chronic steroid-dependent UC. In addition, some patients treated with infliximab can be weaned from infliximab and maintain remission.

A comparative study of the preventative effects exerted by two probiotics, Lactobacillus reuteri and Lactobacillus fermentum, in the trinitrobenzenesulfonic acid model of rat colitis

The intestinal anti-inflammatory effects of two probiotics isolated from breast milk, Lactobacillus reuteri and L. fermentum, were evaluated and compared in the trinitrobenzenesulfonic acid (TNBS) model of rat colitis. Colitis was induced in rats by intracolonic administration of 10 mg TNBS dissolved in 50% ethanol (0.25 ml). Either L. reuteri or L. fermentum was daily administered orally (5 x 10(8) colony-forming units suspended in 0.5 ml skimmed milk) to each group of rats (n 10) for 3 weeks, starting 2 weeks before colitis induction. Colonic damage was evaluated histologically and biochemically, and the colonic luminal contents were used for bacterial studies and for SCFA production. Both probiotics showed intestinal anti-inflammatory effects in this model of experimental colitis, as evidenced histologically and by a significant reduction of colonic myeloperoxidase activity (P<0.05). L. fermentum significantly counteracted the colonic glutathione depletion induced by the inflammatory process. In addition, both probiotics lowered colonic TNFalpha levels (P<0.01) and inducible NO synthase expression when compared with non-treated rats; however, the decrease in colonic cyclo-oxygenase-2 expression was only achieved with L.fermentum administration. Finally, the two probiotics induced the growth of Lactobacilli species in comparison with control colitic rats, but the production of SCFA in colonic contents was only increased when L. fermentum was given. In conclusion, L. fermentum can exert beneficial immunomodulatory properties in inflammatory bowel disease, being more effective than L. reuteri, a probiotic with reputed efficacy in promoting beneficial effects on human health.

Mechanism of glucocorticoid regulation of the intestinal tight junction barrier

A defective intestinal epithelial tight junction (TJ) barrier has been proposed as an important pathogenic factor contributing to the intestinal inflammation of Crohn's disease. Glucocorticoids are first-line therapeutic agents for the treatment of moderate to severe Crohn's disease. Glucocorticoid treatment has been shown to induce retightening of the intestinal TJ barrier defect in Crohn's disease patients. However, the mechanisms that mediate the glucocorticoid therapeutic action on intestinal TJ barrier function remain unknown. The aim of this study was to elucidate the mechanism of glucocorticoid modulation of the intestinal epithelial TJ barrier using an in vitro model system. Filter-grown Caco-2 intestinal epithelial cells were used as an in vitro model to examine the effects of glucocorticoids on basal intestinal epithelial TJ barrier function and on TNF-alpha-induced disruption of the TJ barrier. Glucocorticoids (prednisolone and dexamethasone) did not have a significant effect on baseline Caco-2 TJ barrier function but prevented the TNF-alpha-induced increase in Caco-2 TJ permeability. The glucocorticoid protective effect against the TNF-alpha-induced increase in Caco-2 TJ permeability required activation of the glucocorticoid receptor (GR) complex. The activation of the GR complex resulted in GR complex binding to the glucocorticoid response element (GRE) site on DNA and activation of a GR-responsive promoter. Glucocorticoids inhibited the TNF-alpha-induced increase in myosin light chain kinase (MLCK) protein expression, a key process mediating the TNF-alpha increase in intestinal TJ permeability. The glucocorticoid inhibition of the TNF-alpha-induced increase in MLCK protein expression was due to the binding of the GR complex to a GRE binding site on the MLCK promoter region suppressing the TNF-alpha-induced activation. Glucocorticoids inhibit the TNF-alpha-induced increase in Caco-2 TJ permeability. The prednisolone protective action was mediated by binding of activated GR complex to the GRE site on the MLCK promoter, suppressing the TNF-alpha-induced increase in MLCK gene activity, protein expression, and subsequent opening of the intestinal TJ barrier.

An increase in epithelial cell apoptosis is associated with chronic intestinal nematode infection

It is well established that homeostasis of the intestinal epithelium becomes dysregulated during gastrointestinal helminth infection and is under immune control. An increase in both enterocyte proliferation and the subsequent generation of crypt hyperplasia are hallmarks of chronic infection with Trichuris muris, a large intestinal dwelling nematode. The effect of this parasitic infection on apoptosis induction in the large intestine and its regulation has been neglected. To address this, mice of resistant and susceptible phenotypes were infected with different doses of T. muris, and the levels of epithelial cell apoptosis were determined. It is clear that apoptosis is induced during chronic T. muris infection. This occurs mainly at the base of the cecal crypt, within the stem cell region. The level of apoptosis induced is independent of worm number, suggesting that it is not a consequence of worm-induced damage but rather a mechanism for controlling cell number within the crypt. Neutralization of both gamma interferon and tumor necrosis factor alpha caused a significant reduction in the levels of apoptosis, showing that proinflammatory cytokines generated in response to chronic infection play an important role in apoptosis induction in this system. It is proposed that the generation of proinflammatory cytokines during chronic T. muris infection may play a positive role, by promoting intestinal epithelial cell apoptosis, to counter infection-induced epithelial hyperplasia.

Infliximab Therapy in Children and Adolescents with Inflammatory Bowel Disease

This review summarises the present knowledge of infliximab therapy in children with inflammatory bowel disease (IBD) based on the available published literature. Infliximab, the chimeric monoclonal IgG(1) antibody to tumour necrosis factor-alpha, is indicated for medically refractory luminal and fistulising paediatric Crohn's disease. Recently, ulcerative colitis case series in children and adolescents suggested that infliximab might also be effective for treatment of ulcerative colitis resistant to standard medical therapy. Induction therapy with infliximab 5 mg/kg at weeks 0, 2 and 6 is routinely used. Since the majority of patients will relapse if not re-treated, a long-term approach with systematic re-treatment with 5 mg/kg every 8-12 weeks is recommended. Maintenance therapy every 8 weeks was superior to 12 weeks' administration in maintaining response and remission in the largest-to-date paediatric randomised trial. Concomitant immunosuppressive therapy reduces the risk of infliximab antibody formation and infusion reactions, and prolongs the duration of treatment success. Severe reactions may not be an absolute contraindication to future infliximab therapy. Premedication does not prevent the development of infusion reactions; however, it is indicated for prevention of subsequent infusion reactions. Adverse events and safety findings in children are comparable to those observed in adults. Latent tuberculosis needs to be screened for. Malignancy rates in paediatric patients treated with infliximab do not seem to be increased. However, newly reported cases of hepatosplenic T-cell lymphoma in young patients with IBD treated with infliximab and mercaptopurine therapy raise concern, and long-term follow-up studies are necessary to determine the true malignancy risk.

Targeting nanomedicines in the treatment of Crohn's disease: focus on certolizumab pegol (CDP870)

A variety of targets for therapeutic intervention are based upon advances in understanding of the immunopathogenesis of Crohn's disease. Crohn's disease is initiated by an innate immune response, which eventuates in a T-cell driven process, characterized by a T-helper cell 1 type cytokine profile. Several new treatments now focus on suppressing T-cell differentiation or T-cell inflammation. Since inflammatory bowel disease (IBD) represents a state of dysregulated inflammation, drugs that augment the anti-inflammatory response have the potential to downregulate inflammation and thereby hopefully modify the disease. Tumour necrosis factor (TNF) is a major target of research and clinical investigation. TNF has proinflammatory effects in the intestinal mucosa and is a pivotal cytokine in the inflammatory cascade. Certolizumab pegol (CDP870) is a PEGylated, Fab' fragment of a humanized anti-TNF-alpha monoclonal antibody. PEGylation increases the half-life, reduces the requirement for frequent dosing, and possibly reduces antigenicity as well. Certolizumab has been shown in Phase III trials to achieve and maintain clinical response and remission in Crohn's disease patients. It improves the quality of life. Certolizumab pegol will be indicated for moderately to severely active Crohn's disease, but it is not yet licensed in Europe or the US. It is not possible to construct an algorithm for treatment, but when compared with infliximab the two principal advantages are likely to be lower immunogenicity (as shown by anti-drug antibodies, absence of infusion reactions, and low rate of antinuclear antibodies), and a subcutaneous route of administration. These two factors may be sufficient to promote it up the pecking order of anti-TNF agents.

Systematic review: Infliximab therapy in ulcerative colitis

AIM

To perform a systematic review and meta-analysis on the efficacy and tolerance of infliximab in ulcerative colitis.

SELECTION OF STUDIES

evaluating efficacy of infliximab in ulcerative colitis. For the meta-analysis, randomized clinical trials comparing infliximab vs. placebo/steroids.

SEARCH STRATEGY

electronic and manual. Study quality: independently assessed by two reviewers.

DATA SYNTHESIS

meta-analysis combining the odds ratios (OR).

RESULTS

Thirty-four studies (896 patients) evaluated infliximab therapy in UC, with heterogeneous results. Mean short-term (2.3 weeks) response and remission with infliximab was 68% (95% CI 65-71%) and 40% (36-44%). Mean long-term (8.9 months) response and remission was 53% (49-56%) and 39% (35-42%). Five randomized double-blind studies compared infliximab with placebo, the meta-analysis showing an advantage (P < 0.001) of infliximab in all endpoints (short-/long-term response/remission): ORs from 2.7 to 4.6, and number-needed-to-treat (NNT) from 3 to 5. Similar infliximab response was calculated independently of the indication (steroid-refractory/non-steroid-refractory) or the dose (5/10 mg/kg). Adverse effects were reported in 83% and 75% of the infliximab and placebo-treated patients (OR = 1.52; 95% CI 1.03-2.24; number-needed-to-harm (NNH) was 14).

CONCLUSION

Infliximab is more effective than placebo, with an NNT from 3 to 5, for the treatment of moderate-to-severe UC, achieving clinical remission in 40% of the patients at approximately 9 months of follow-up. Further studies are necessary to confirm the long-term efficacy of infliximab in ulcerative colitis.

Exploitation of the nicotinic anti-inflammatory pathway for the treatment of epithelial inflammatory diseases

Discoveries in the first few years of the 21st century have led to an understanding of important interactions between the nervous system and the inflammatory response at the molecular level, most notably the acetylcholine (ACh)-triggered, α7-nicotinic acetylcholine receptor (α7nAChR)-dependent nicotinic anti-inflammatory pathway. Studies using the α7nAChR agonist, nicotine, for the treatment of mucosal inflammation have been undertaken but the efficacy of nicotine as a treatment for inflammatory bowel diseases remains debatable. Further understanding of the nicotinic anti-inflammatory pathway and other endogenous anti-inflammatory mechanisms is required in order to develop refined and specific therapeutic strategies for the treatment of a number of inflammatory diseases and conditions, including periodontitis, psoriasis, sarcoidosis, and ulcerative colitis.

Infliximab in ulcerative colitis

Infliximab is effective for treatment of moderate-to-severe UC and is recommended for patients who have had an inadequate response to medical therapy or who are intolerant of or do not desire to take the potential risk of using specific agents including immunomodulators (cyclosporine A, azathioprine, or 6-mercaptopurine), corticosteroids, and, potentially, mesalamine. Future trials are needed to assess the efficacy of infliximab with immunomodulators to see if additional benefit is achieved so that the risk-benefit ratio is positive. Based on the favorable efficacy of infliximab for UC therapy, the ground work has been established for evaluating infliximab and addressing some of the many unanswered questions and also for assessing other anti-TNF agents and streamlining the anti-TNG antibody to improve efficacy, reduce side effects, and ease administration.

Lactobacillus fermentum, a probiotic capable to release glutathione, prevents colonic inflammation in the TNBS model of rat colitis

BACKGROUND AND AIMS

Inflammatory bowel disease is associated with intestinal oxidative stress. In the present study we test the preventative effect of Lactobacillus fermentum, a probiotic that produces per se glutathione, in the trinitrobenzenesulphonic acid (TNBS) model of rat colitis.

METHODS

Colitis was induced in rats by intracolonic administration of 10 mg of TNBS dissolved in 0.25 ml of 50% ethanol. L. fermentum was administered orally (5x10(8) CFU suspended in 0.5 ml of skim milk) to a group of rats for 3 weeks, starting 2 weeks before colitis induction. Colonic damage was evaluated both histologically and biochemically, and the colonic luminal contents were used for bacterial studies as well as for short chain fatty acid (SCFA) production.

RESULTS

L. fermentum treatment resulted in an amelioration of the inflammatory response in colitic rats as evidenced histologically and by a significant reduction of colonic MPO activity (P<0.05). The probiotic partially counteracted the colonic glutathione depletion induced by the inflammatory process. In addition, probiotic-treated colitic rats showed significant lower colonic tumour necrosis factor (TNF)alpha levels (P<0.01) and inducible nitric oxide synthase (iNOS) expression when compared to non-treated rats. Finally, the probiotic induced growth of Lactobacilli species and production of SCFA in colonic contents in comparison with control colitic rats.

CONCLUSION

Administration of the probiotic L. fermentum facilitates the recovery of the inflamed tissue in the TNBS model of rat colitis, an effect associated with increased levels of glutathione as well as with amelioration of the production of some of the mediators involved in the inflammatory response of the intestine, such as TNFalpha and NO.

Localized colonic inflammation increases cytokine levels in distant small intestinal segments in the rat

Local inflammation in the colon has been associated with nutrient malabsorption and altered motility in the small bowel. These remote effects suggest the release of mediators which can act (or alter) the function of intestinal segments located far from the primary area of inflammation. This study describes the changes in the expression of pro-inflammatory cytokines in the colon and in various segments of the small intestine in two rat models of experimental colitis. Colitis was induced by the intracolonic administration of 100 microL of 6% iodoacetamide or 250 microL of 2, 4, 6-trinitrobenzene sulfonic acid. Levels of interleukin one beta, interleukin 6, and tumor necrosis factor alpha were measured by ELISA in tissue homogenate sampled from duodenum, jejunum, ileum and colon at different time intervals. In homogenates of strips isolated from duodenum, jejunum and ileum, tumor necrosis alpha and interleukin-6, increased significantly 3-6 h after iodoacetamide or TNBS administration and remained elevated until the colonic inflammation subsided. Interleukin one beta showed comparable but delayed increase. Similar, but more pronounced increase of the three cytokines was noticed in areas of the colon adjacent to the ulcer. Histologic examinations revealed important inflammatory changes in the colon; however, examination of sections from the small intestines did not reveal significant differences between controls and rats with colitis. In conclusion, expression of pro-inflammatory cytokines is increased in remote segments of the small intestines during colitis. The findings may provide a partial explanation or a molecular substrate for the associated small bowel dysfunction.

Factors affecting recurrence in patients with Crohn's disease under nutritional therapy

PURPOSE

This retrospective study was designed to determine risk factors for recurrence of Crohn's disease under enteral nutrition.

METHODS

The clinical course of 145 patients with Crohn's disease, who were primarily induced into remission by total parenteral nutrition, was reviewed. The patients were classified into two groups: enteral nutrition group (n = 98; >/=1,200 kcal/day of enteral nutrition), or nonenteral nutrition group (n = 47;<1,200 kcal/day of enteral nutrition) according to the amount of their daily elemental or polymeric diet. Contributions of enteral nutrition and other clinical variables to the recurrence were analyzed retrospectively. A Crohn's disease activity index of >150 plus an increase in Crohn's disease activity index of >70 from the baseline value was defined as recurrence.

RESULTS

Forty-two patients in the enteral nutrition group and 29 patients in the nonenteral nutrition group recurred during periods ranging from 3 to 159 months. The cumulative rate of recurrence was significantly higher in the nonenteral nutrition group than in the enteral nutrition group (P = 0.047). Among the Crohn's disease patients in the enteral nutrition group, penetrating type (relative risk, 3.89; 95 percent confidence interval, 1.58-9.62), colonic involvement (relative risk, 3.10; 95 percent confidence interval, 1.39-6.9), and previous history of surgery (relative risk, 2.48; 95 percent confidence interval, 1.16-5.33) were factors that significantly affected recurrence. In contrast, penetrating type was the only possible factor associated with recurrence in the nonenteral nutrition group (relative risk, 2.75; 95 percent confidence interval, 0.96-7.81).

CONCLUSIONS

Among patients with Crohn's disease under maintenance enteral nutrition, the risk of recurrence differs according to the disease type and the site of involvement. The maintenance treatment by enteral nutrition alone seems insufficient for patients with penetrating type or with colonic involvement.

[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.

Down-regulation of interferon-gamma parallels clinical response to selective leukocyte apheresis in patients with inflammatory bowel disease: a 12-month follow-up study

BACKGROUND & AIMS

Pilot studies have indicated a therapeutic role for an apheresis device (Adacolumn) that selectively adsorbs leukocytes in patients with inflammatory bowel diseases. It may also exert immunoregulatory effects contributing to its clinical efficacy. This study aimed to correlate the clinical response to leukocyte apheresis with the expression of key cytokines in mucosal tissue, in peripheral leukocytes, and in plasma.

METHODS

Ten patients (seven with Crohn's disease and three with ulcerative colitis, median age: 31 years) with mild to moderately chronic activity were recruited to an open study. Patients were refractory to or had a relapse despite conventional treatment including azathioprine. Leukocyte apheresis was performed once a week for five consecutive weeks. Clinical efficacy was assessed on week 7 and after 12 months. Colonoscopy with multiple biopsies was performed at the start of the study and after 7 weeks for semiquantitative immunohistochemical analyses of cytokines. Cytokine levels in blood and the proportion of cytokine producing CD4+ and CD8+ lymphocytes were determined.

RESULTS

The apheresis procedures were well tolerated and no major adverse events were encountered. The median clinical activity score decreased from 12 to 7 on week 7 (P=0.031, n=9) and to 4 after 12 months (P=0.004, n=9). Five patients were in clinical remission at the 12th month. Tissue interferon (IFN)-gamma-positive T-cells decreased in clinical responders (P=0.027) after apheresis. In parallel, significantly lower levels of IFN-gamma-producing lymphocytes were detected in peripheral blood. IFN-gamma-positive cells in pretreatment biopsies completely disappeared or decreased in posttreatment biopsies sampled on week 7 in responders (P=0.027) and appeared to predict the maintenance of long-term remission or response after 12 months.

CONCLUSIONS

Leukocyte apheresis is a novel and safe nonpharmacological adjunct therapy that may prove useful in steroid refractory or dependent patients when conventional drugs have failed. Down-regulation of IFN-gamma in mucosal biopsies and in peripheral leukocytes may be a predictive marker for sustained, long-term response.

De novo design TNF-α antagonistic peptide based on the complex structure of TNF-α with its neutralizing monoclonal antibody Z12

Tumor necrosis factor-alpha (TNF-alpha) antagonists have become therapeutic drugs for immunological diseases including rheumatoid arthritis, inflammatory bowel disease, Crohn's disease, etc. Low molecular weight synthetic peptides can mimic the binding sites of TNF-alpha receptors and block the activity of TNF-alpha. Based on the 3-D complex structure of TNF-alpha with its neutralizing monoclonal antibody (Mab) Z12, an antagonistic peptide (AP) was rationally de novo designed. The designed AP possessed similar structural character and potential bioactivity with Mab Z12. AP could competitively inhibit the binding of Mab Z12 to TNF-alpha, TNF-alpha-meditated caspase activation and TNF-alpha-induced cytotoxicity on murine L929 cells with a dose-dependent fashion. This study highlights the potential of computation-aided method for the design of novel peptides with the ability to block the deleterious biological effects of TNF-alpha.

Osteopontin deficiency protects mice from Dextran sodium sulfate-induced colitis

BACKGROUND

Osteopontin (OPN), a secreted glycoprotein that promotes TH1 immune responses, is involved in several inflammatory conditions. Recently, OPN plasma levels have been demonstrated to be elevated in patients with Crohn's disease. From this evidence, we investigated in the present study whether OPN deficiency protects mice against dextran sodium sulfate (DSS)-induced colitis.

MATERIALS AND METHODS

Colitis was induced in OPN -/- mice and matched wild-type Black Swiss control mice by adding 3.5% DSS to their drinking water. Disease progression was evaluated for 10 days by measuring body weight, stool consistency, rectal bleeding, colon lengths, histology, and immunohistochemistry. Levels of the acute-phase protein serum amyloid A, O PN, the proinflammatory cytokines interleukin (IL)-6 and IL-12, and the anti-inflammatory cytokine IL-10 were measured in the serum and, in the case of IL-10 and IL-12, in supernatants from colonic explants at the end of treatment.

RESULTS

After DSS treatment, OPN -/- mice exhibited significantly decreased disease activity compared with wild-type mice, as evidenced by reduced rectal bleeding, weight loss, and histological intestinal injury (P < 0.002). Furthermore, serum levels of serum amyloid A and IL-6 increased to a lesser extent (P < 0.001), which also was the case for the release of IL-12 by colonic explants (P < 0.01). The release of IL-10 by colonic explants, however, was increased (P < 0.01). Serum levels of IL-10 and IL-12 were not affected by DSS treatment in both wild-type and OPN-/- mice. Macrophage infiltration into inflamed colonic tissue also was markedly attenuated in DSS-treated OPN -/- mice compared with wild-type mice.

CONCLUSIONS

This study shows that OPN deficiency significantly protected mice from colitis by attenuating the TH1 response and macrophage chemotaxis. OPN may represent a novel attractive target for pharmacological treatment of inflammatory bowel disease.

Safety issues with biological therapies for inflammatory bowel disease

PURPOSE OF REVIEW

The purpose of this review is to summarize recent evidence describing specific complications associated with the use of biological therapy derived from controlled trials and from post-marketing surveillance.

RECENT FINDINGS

Biological therapies, particularly anti-tumour necrosis factor antibodies, are increasingly used in patients with Crohn's disease and ulcerative colitis. Some adverse events, such as serious infections, are a consequence of the immunomodulatory effect of biological agents, while other complications, such as the induction of autoimmune phenomena, neurotoxicity and the development of an immune response to engineered proteins, are class or molecule-specific. Although the immunopathogenesis of these side effects is often a matter of debate, they have been observed not only in inflammatory bowel disease, but also in other immune disorders such as rheumatoid arthritis and psoriasis.

SUMMARY

The benefits of biological agents clearly outweigh the risks. Nevertheless, they are associated with specific toxicity, and this requires the attention of the clinician.

A new transcription factor that regulates TNF-alpha gene expression, LITAF, is increased in intestinal tissues from patients with CD and UC

BACKGROUND

The proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) plays a key role in the pathogenesis of Crohn's disease (CD) and ulcerative colitis (UC). Recently, a new transcription factor termed LITAF (lipopolysaccharide-induced TNF-alpha factor) was shown to mediate TNF-alpha expression in human macrophages by direct binding to specific sequences in the promoter region of the TNF-alpha gene.

METHODS

In this report, we identified LITAF in resected ileal and colonic tissues from patients with CD and UC by immunohistochemistry, real-time polymerase chain reaction, and Western blot analysis. LITAF expression in inflamed and noninflamed areas of the tissues was compared.

RESULTS

This is the first demonstration of LITAF, a newly discovered transcription factor that regulates TNF-alpha gene transcription in ileal and colonic tissues from patients with either CD or UC. LITAF immunostaining was localized to lamina propria macrophages and was markedly increased relative to tissues from controls without inflammatory bowel disease. In patients with CD, a 5-fold increase in LITAF mRNA was measurable in noninflamed colonic tissues compared with controls without inflammatory bowel disease. LITAF mRNA in tissues from inflamed areas of the colon was increased by an additional 60% compared with noninflamed tissues. In patients with UC, LITAF mRNA levels in colonic tissues resected from noninflamed areas were elevated 15-fold above nondisease controls, but they were not different in tissues resected from inflamed areas. Western blot analysis showed that in patients with CD, there was a marked increase in LITAF protein in inflamed areas compared with noninflamed areas. LITAF protein levels were not different between noninflamed and inflamed tissues obtained from patients with UC. TNF-alpha mRNA and protein levels paralleled LITAF. Similarly, in inflamed ileal tissues from patients with CD, LITAF is also localized to lamina propria macrophages. LITAF mRNA and LITAF protein were significantly increased in inflamed ileal tissues compared with noninflamed areas.

CONCLUSIONS

LITAF is readily detectable in ileal and colonic tissues from patients with either CD or UC, is significantly elevated above controls, and is localized to macrophages, a major source of TNF-alpha. These data provide strong evidence of a role for LITAF in the pathophysiological regulation of the TNF-alpha gene and underscore the potential value of anti-LITAF strategies in the clinical management of these diseases.

A simple biological score for predicting low risk of short-term relapse in Crohn's disease

BACKGROUND

In Crohn's disease, studies have evaluated the ability of biological markers to predict relapse in the next 12 to 18 months, without differentiating early from late relapses. The aim of this study was to look for biological markers of short-term relapse.

MATERIALS AND METHODS

In a previous therapeutic trial, patients with a medically induced clinical remission had biological markers evaluated and updated every 6 weeks. A Cox model with time-dependent covariates was used for analysis.

RESULTS

Among the 71 patients, 38 had a relapse. Multivariate analysis selected 2 markers predictive of relapse: C-reactive protein >20 mg/L and erythrocyte sedimentation rate >15 mm. A binary biological predictive score was derived: "negative" when both were lower than their limits, "positive" when otherwise. The relative risk of short-term relapse for patients with a positive score compared to those with a negative score was 8.0 (95% confidence interval 2.8-22.9). Sensitivity of the score was 89% and specificity was 43%. Assuming a 10% relapse rate every 6 weeks, negative and positive predictive values were 97% and 15%, respectively.

CONCLUSIONS

This simple biological score can predict short-term maintenance of remission in Crohn's disease and may help physicians in the follow-up of patients in clinical remission.

Pharmacogenetics in inflammatory bowel disease

Pharmacogenetics is the study of the association between variability in drug response and (or) drug toxicity and polymorphisms in genes. The goal of this field of science is to adapt drugs to a patient's specific genetic background and therefore make them more efficacious and safe. In this article we describe the variants in genes that influence either the efficacy or toxicity of common drugs used in the treatment of inflammatory bowel diseases (IBD), ulcerative colitis (UC), and Crohn's disease (CD) including sulfasalazine and mesalazine, azathioprine (AZA) and 6-mercaptopurine (6-MP), methotrexate (MTX), glucocorticosteroids (CSs) and infliximab. Furthermore, difficulties with pharmacogenetic studies in general and more specifically in IBD are described. Although pharmacogenetics is a promising field that already contributed to a better understanding of some of the underlying mechanisms of action of drugs used in IBD, the only discovery translated until now into daily practice is the relation between thiopurine S-methyltransferase (TPMT) gene polymorphisms and hematological toxicity of thiopurine treatment. In the future it is necessary to organize studies in well characterized patient cohorts who have been uniformly treated and systematically evaluated in order to quantitate drug response more objectively. An effort should be made to collect genomic DNA from all patients enrolled in clinical drug trials after appropriate informed consent for pharmacogenetic studies.

Reduction of experimental colitis in the rat by inhibitors of glycogen synthase kinase-3beta

The effects of the inhibitors of glycogen synthase kinase-3beta (GSK-3beta), TDZD-8 and SB 415286, which can substantially reduce the systemic inflammation associated with endotoxic shock in vivo, have now been investigated on the acute colitis provoked by trinitrobenzene sulphonic acid (TNBS) in the rat. Administration of the GSK-3beta inhibitor TDZD-8 (0.1, 0.33 or 1.0 mg kg-1, s.c., b.i.d., for 3 days) caused a dose-dependent reduction in the colonic inflammation induced by intracolonic TNBS assessed after 3 days, both as the area of macroscopic involvement and as a score using 0-10 scale. Likewise, following administration of the GSK-3beta inhibitor SB 415286 (0.1, 0.33 or 1.0 mg kg-1, s.c., b.i.d., for 3 days), the extent and degree of the TNBS-provoked colonic inflammation was reduced. Administration of either TDZD-8 or SB 415286 reduced the fall in body weight following challenge with TNBS at each dose level studied. The increase in myeloperoxidase activity, an index of neutrophil infiltration into the TNBS-induced inflamed colon, was significantly inhibited by both TDZD-8 and SB 415286 at each dose level. The increase in the levels of the proinflammatory cytokine, TNF-alpha, in the inflamed colon was also significantly inhibited by either compound at the highest doses evaluated. The elevated levels of the transcription factor NF-kappaB subunit p65, as determined by Western blot in the nuclear extracts from the TNBS-provoked inflamed colonic tissue, were dose-dependently reduced by TDZD-8 or SB 415286 treatment. These findings demonstrate that two chemically distinct selective inhibitors of the activity of GSK-3beta reduce the inflammation and tissue injury in a rat model of acute colitis. The mechanisms underlying this anti-inflammatory action may be related to downregulation of NF-kappaB activity, involved in the generation of proinflammatory mediators.

Serious infections and mortality in association with therapies for Crohn's disease: TREAT registry

BACKGROUND & AIMS

Long-term safety data for infliximab and other therapies in Crohn's disease (CD) are needed.

METHODS

We prospectively evaluated patients for prespecified safety-related outcomes.

RESULTS

As of August 2004, 6290 patients were enrolled; 3179 received infliximab (5519 patient-years), 87% of whom received at least 2 infusions, and 3111 received other therapies (6123 patient-years). The mean length of follow-up evaluation was 1.9 years. More infliximab-treated patients had moderate-to-severe (30.8% vs 10.3%) or severe-fulminant (2.5% vs .6%) CD, and had surgical (17.5% vs 13.8%) or medical (14.4% vs 9.1%) hospitalizations in the previous year. More patients were taking prednisone (27.4% vs 16.1%), immunomodulators (49.4% vs 32.2%), or narcotic analgesics (9.8% vs 5.4%) when compared with those receiving other therapies (P<.001, all comparisons). The mortality rates were similar for infliximab- and non-infliximab-treated patients (.53 per 100 patient-years vs .43; relative risk, 1.24; 95% confidence interval [CI], .73-2.10). In multivariate logistic regression analysis, only prednisone was associated with an increased mortality risk (odds ratio [OR], 2.10; 95% CI, 1.15-3.83; P=.016). Although the unadjusted analysis showed an increased risk for infection with infliximab use, multivariate logistic regression analysis suggested that infliximab was not an independent predictor of serious infections (OR, .99; 95% CI, .64-1.54). Factors independently associated with serious infections included prednisone use (OR, 2.21; 95% CI, 1.46-3.34; P<.001), narcotic analgesic use (OR, 2.38; 95% CI, 1.56-3.63; P<.001), and moderate-to-severe disease activity (OR, 2.11; 95% CI, 1.10-4.05; P=.024).

CONCLUSIONS

Mortality rates were similar between infliximab- and non-infliximab-treated patients. The increased risk for serious infection observed with infliximab likely was owing to disease severity and prednisone use.

Discovery of S-[5-amino-1-(4-fluorophenyl)-1H-pyrazol-4-yl]-[3-(2,3-dihydroxypropoxy)phenyl]methanone (RO3201195), an orally bioavailable and highly selective inhibitor of p38 MAP kinase

A novel class of highly selective inhibitors of p38 MAP kinase was discovered from high throughput screening. The synthesis and optimization of a series of 5-amino-N-phenyl-1H-pyrazol-4-yl-3-phenylmethanones is described. An X-ray crystal structure of this series bound in the ATP binding pocket of unphosphorylated p38alpha established the presence of a unique hydrogen bond between the exocyclic amine of the inhibitor and threonine 106 which likely contributes to the selectivity for p38. The crystallographic information was used to optimize the potency and physicochemical properties of the series. The incorporation of the 2,3-dihydroxypropoxy moiety on the pyrazole scaffold resulted in a compound with excellent drug-like properties including high oral bioavailability. These efforts identified 63 (RO3201195) as an orally bioavailable and highly selective inhibitor of p38 which was selected for advancement into Phase I clinical trials.

Infliximab for the treatment of pyoderma gangrenosum: a randomised, double blind, placebo controlled trial

BACKGROUND

Pyoderma gangrenosum (PG) is a chronic ulcerating skin condition that often occurs in association with inflammatory bowel disease. There have been a number of reports of PG responding to infliximab, a monoclonal antibody against tumour necrosis factor alpha.

AIM

In the first randomised placebo controlled trial of any drug for the treatment of PG, we have studied the role of infliximab in this disorder.

SUBJECTS

Patients 18 years of age or older with a clinical diagnosis of PG were invited to take part.

METHODS

Patients were randomised to receive an infusion of infliximab at 5 mg/kg or placebo at week 0. Patients were then assessed at week 2 and non-responders were offered open labelled infliximab. The primary end point was clinical improvement at week 2, with secondary end points being remission and improvement at week 6.

RESULTS

Thirty patients were entered into the study. After randomisation, 13 patients received infliximab and 17 patients received placebo. At week 2, significantly more patients in the infliximab group had improved (46% (6/13)) compared with the placebo group (6% (1/17); p = 0.025). Overall, 29 patients received infliximab with 69% (20/29) demonstrating a beneficial clinical response. Remission rate at week 6 was 21% (6/29). There was no response in 31% (9/29) of patients.

CONCLUSIONS

This study has demonstrated that infliximab at a dose of 5 mg/kg is superior to placebo in the treatment of PG. Open label treatment with infliximab also produced promising results. Infliximab treatment should be considered in patients with PG.

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.

Recent advances in the etiology and treatment of inflammatory bowel disease

Crohn's disease and ulcerative colitis, together comprising the inflammatory bowel diseases, currently affect up to 2 million people in the western developed countries. The pathogenesis of the disease is a complex one in which genetic, immunogenic, microbial and environmental factors contribute to the etiology of the disease. Recent advances in understanding the molecular mechanisms that determine this complex entity have provided insight for promising new therapies.

The Response of Human Epithelial Cells to TNF Involves an Inducible Autocrine Cascade

Tumor necrosis factor (TNF) is a proinflammatory cytokine that induces conflicting pro- and antiapoptotic signals whose relative strengths determine the extent of cell death. TNF receptor (TNFR) has been studied in considerable detail, but it is not known how crosstalk among antagonistic pro- and antiapoptotic signals is achieved. Here we report an experimental and computational analysis of crosstalk between prodeath TNF and prosurvival growth factors in human epithelial cells. By applying classifier-based regression to a cytokine-signaling compendium of approximately 8000 intracellular protein measurements, we demonstrate that cells respond to TNF both directly, via activated TNF receptor, and indirectly, via the sequential release of transforming growth factor-alpha (TGF-alpha), interleukin-1alpha (IL-1alpha), and IL-1 receptor antagonist (IL-1ra). We refer to the contingent and time-varying series of extracellular signals induced by TNF as an "autocrine cascade." Time-dependent crosstalk of synergistic and antagonistic autocrine circuits may serve to link cellular responses to the local environment.

Tumour necrosis factor-alpha production stimulated by heat shock protein 70 and its inhibition in circulating dendritic cells and cells eluted from mucosal tissues in Crohn's disease

Summaryand interleukin (IL)-12 by dendritic cells (DC) from patients with Crohn's disease. TNF-alpha concentration was increased significantly when DC from Crohn's disease were stimulated with HSP70 or CD40L and this was associated with signalling by the extracellular signal regulated kinase (ERK) 1/2 and p38 mitogen activated protein (MAP) kinase pathway. IL-12 production was also increased when DC were stimulated with HSP70. Cells eluted from inflamed intestinal mucosa from Crohn's disease, stimulated with HSP70, CD40L or lipopolysaccharide produced significantly greater TNF-alpha and IL-12 concentrations than cells from uninflamed mucosa. Significant inhibition of TNF-alpha production was demonstrated when DC from peripheral blood mononuclear cells or cells eluted from intestinal mucosa of Crohn's disease were treated with either the HSP70 inhibitory peptide (aa 457-496) or peptides derived from CD40 and CD40L. These inhibitory peptides target the CD40-CD40L and the emerging CD40-HSP70 co-stimulatory pathway. Our findings offer a novel strategy to prevent excessive production of TNF-alpha in Crohn's disease.

Functional diversity of flavonoids in the inhibition of the proinflammatory NF-kappaB, IRF, and Akt signaling pathways in murine intestinal epithelial cells

The molecular understanding of nutritional factors in the process of host factor-mediated activation of the intestinal epithelium may play an important role in the assessment of adjunct nutritional therapy for chronic intestinal inflammation. We characterized the molecular mechanisms of flavonoids including apigenin, luteolin, genistein, 3'-hydroxy-flavone, and flavone in inhibiting tumor necrosis factor-alpha (TNF)-induced interferon-induced protein (IP)-10 gene expression in the murine intestinal epithelial cell (IEC) line Mode-K. We demonstrated that 3'-hydroxy-flavone but not the chemical core structure flavone blocked TNF-alpha-induced nuclear factor (NF)-kappaB transcriptional activity and IP-10 expression at the level of NF-kappaB/IkappaBalpha phosphorylation/degradation by inhibiting IkappaB kinase activity. Although 3'-hydroxy-flavone effectively triggered p38 mitogen-activated protein kinase signaling and late caspase-3 cleavage, the induction of apoptotic cell death in TNF-activated IEC was not the primary mechanism inhibiting NF-kappaB transcriptional activity and IP-10 expression. In addition to the compound-specific inhibition of TNF-induced NF-kappaB DNA binding and NF-kappaB transcriptional activity, apigenin and luteolin selectively blocked Akt phosphorylation/activity. The ability of these polyphenolic compounds to target various signal transduction pathways was further supported by the observation that luteolin and 3'-hydroxy-flavone selectively induced interferon regulatory factor (IRF)-1 degradation. Finally, we showed that genistein blocked IP-10 but not IL-6 expression through NF-kappaB, IRF, and Akt independent mechanisms, demonstrating the functional diversity of flavonoids in inhibiting proinflammatory processes in IEC. In conclusion, we provide molecular evidence for the presence of characteristic inhibition patterns of these polyphenolic compounds to inhibit proinflammatory gene expression in IEC through the specific modulation of the NF-kappaB, IRF and Akt signaling pathways.