Location of tumour necrosis factor alpha by immunohistochemistry in chronic inflammatory bowel disease

Use of atorvastatin as an anti-inflammatory treatment in Crohn's disease

BACKGROUND AND PURPOSE

Experimental and clinical investigations have revealed that statins can downregulate both acute and chronic inflammatory processes. Whether statins express anti-inflammatory activities in the treatment of Crohn's disease is unknown.

EXPERIMENTAL APPROACH

Ten patients were given 80 mg atorvastatin once daily for 13 weeks and then followed up for 8 weeks after the treatment. The anti-inflammatory effects of statin were assessed by measuring levels of plasma C-reactive protein (CRP), soluble (s) CD14, tumour necrosis factor (TNF)-alpha, sTNFRI and II, CCL2 and 8 and the mucosal inflammation by faecal calprotectin. Circulating monocytes were subgrouped and their chemokine receptor expression of CCR2 and CX(3)CR1 were analysed.

KEY RESULTS

In 8 of 10 patients, atorvastatin treatment reduced CRP (P=0.008) and sTNFRII (P=0.064). A slight decrease in plasma levels of sCD14, TNF-alpha and sTNFRI was observed in 7/10 patients and faecal calprotectin was reduced in 8/10 patients. We also observed that the treatment diminished expression of CCR2 and CX(3)CR1 on monocyte populations (P=0.014). At the follow-up visit, 8 weeks after the atorvastatin treatment was terminated, CRP levels had returned to those seen before the treatment.

CONCLUSIONS AND IMPLICATIONS

Our findings imply that atorvastatin therapy reduces inflammation in patients with Crohn's disease and, therefore, encourage further investigations of statin-mediated protective effects in inflammatory bowel diseases.

Adalimumab for the treatment of Crohn's disease

The advent of biologic therapy for Crohn's disease has revolutionized our approach to disease management and redefined our goals. Infliximab (Remicade), an intravenously delivered murine-chimeric monoclonal antibody against TNF-alpha was released in 1998 and shown to have significant benefits in patients with refractory luminal and fistulizing Crohn's disease. Since then other anti-TNF strategies have undergone investigation with variable results. Adalimumab (Humira), a self administered, subcutaneous, fully human monoclonal antibody against TNF-alpha represents the next generation of therapy. It has demonstrated efficacy for induction and maintenance of remission in patients with moderate-to-severe Crohn's in three large double-blind, placebo-controlled, randomized trials. In addition it has demonstrated steroid-sparing properties and the ability to reduce hospitalizations and improve quality of life. It is anticipated, given its clinical efficacy, its fully human nature, and the convenience of self administration that it will have a significant effect on the management of Crohn's disease.

Infliximab in ulcerative colitis

Infliximab, a monoclonal anti-TNF-alpha antibody, is commonly used for treatment of moderate to severe Crohn's disease (CD). Its role in the treatment for ulcerative colitis (UC) remains controversial. We review the role of TNF-alpha in the pathogenesis of UC and describe the randomized, double-blind, placebo-controlled trials and systematic reviews that assess the efficacy of infliximab in the treatment of moderate to severe UC.

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.

Biological agents for ulcerative colitis: hypes and hopes

Ulcerative colitis (UC) is an idiopathic chronic inflammatory disease of the colonic mucosa. Over the last decade, the increasing knowledge on the pathogenic mechanisms underlying intestinal inflammation has led to the development of a number of biological agents, mainly addressed to molecules and/or pathways demonstrated to have a pathogenic role in UC. In UC, clinical course and therapeutic decisions mainly depend on disease activity and extent. While therapeutic approach to mild-to-moderate UC by using aminosalicylates and corticosteroids has been well established, treatment of severe UC is far from being satisfactory. A severe attack of UC remains a challenge to be managed jointly by gastroenterology, surgery, and intensive care units. However, the recent introduction of biological therapies has led to promising changes in the management of UC patients. Aim of this paper is to review the recent advances and future perspectives for the use of biological agents in UC.

New therapeutic strategies for treatment of inflammatory bowel disease

Although the precise etiology of inflammatory bowel disease (IBD) still remains unclear, considerable progress has been made in the identification of cytokine-mediated signaling pathways involved in the inflammatory process. Recent data have clearly shown that these pathways induce augmented intestinal T-cell activation and thus resistance to apoptosis, which is a central process in disease pathogenesis, as it impairs mucosal homeostasis. Therefore, novel therapeutic strategies aim at restoring activated effector T-cell susceptibility to apoptosis in the gut, based on a pathophysiological rationale. This development is best exemplified by the emergence of agents that target the TNF pathway, IL-6 trans-signaling, and the IL-12/IL-23 pathway. These compounds give hope for the development of new strategies aiming at more effective and less toxic therapies for IBD.

Use of infliximab in the prevention and delay of colectomy in severe steroid dependant and refractory ulcerative colitis

AIM: To determine if infliximab can prevent or delay surgery in refractory ulcerative colitis (UC).

METHODS: UC patients who failed to have their disease controlled with conventional therapies and were to undergo colectomy if infliximab failed to induce a clinical improvement were reviewed. Patients were primarily treated with a single 5 mg/kg infliximab dose. The Colitis Activity Index (CAI) was used to determine response and remission. Data of 8 wk response and colectomy rates at 6 mo and 12 mo were collected.

RESULTS: Fifteen patients were included, 7 with UC unresponsive or intolerant to IV hydrocortisone, and 8 with active disease despite oral steroids (all but one with therapeutic dosage and duration of immunomodulation). All the IV hydrocortisone-resistant/intolerant patients had been on azathioprine/6-MP < 8 wk. At 8 wk, infliximab induced a response in 86.7% (13/15) with 40% in remission (6/15). Within 6 mo of treatment 26.7% (4/15) had undergone colectomy and surgery was avoided in 46.6% (7/15) at 12 mo. The colectomy rate at 12 mo in those on immunomodulatory therapy < 8 wk at time of infliximab was 12.5% (1/8) compared with 100% (7/7) in patients who were on long-term maintenance immunomodulators (P < 0.02).

CONCLUSION: Infliximab prevented colectomy due to active disease in immunomodulatory-naïve, refractory UC patients comparable to the use of Cyclosporine. In patients, however, on effective dosage and duration of immunomodulation at time of infliximab therapy colectomy was not avoided.

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.

TNF-mediated inflammatory disease

TNF was originally described as a circulating factor that can cause necrosis of tumours, but has since been identified as a key regulator of the inflammatory response. This review describes the known signalling pathways and cell biological effects of TNF, and our understanding of the role of TNF in human disease. TNF interacts with two different receptors, designated TNFR1 and TNFR2, which are differentially expressed on cells and tissues and initiate both distinct and overlapping signal transduction pathways. These diverse signalling cascades lead to a range of cellular responses, which include cell death, survival, differentiation, proliferation and migration. Vascular endothelial cells respond to TNF by undergoing a number of pro-inflammatory changes, which increase leukocyte adhesion, transendothelial migration and vascular leak and promote thrombosis. The central role of TNF in inflammation has been demonstrated by the ability of agents that block the action of TNF to treat a range of inflammatory conditions, including rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel disease and psoriasis. The increased incidence of infection in patients receiving anti-TNF treatment has highlighted the physiological role of TNF in infectious diseases.

National Psoriasis Foundation clinical consensus on psoriasis comorbidities and recommendations for screening

There have been several articles and reports in recent months about comorbidities and risks that affect psoriasis patients in addition to their underlying disease. This piece reviews the current literature and begins to address what should be done with this new information by updating the clinician about what health screening tests, preventative exams, and referrals should be considered in this population.

Infliximab: the evidence for its place in therapy in ulcerative colitis

INTRODUCTION

Refractory ulcerative colitis has a high, unmet medical need for avoiding steroid dependency and avoiding colectomy. Controlled trials with biologic agents have recently been reported.

AIMS

We aimed to review the current evidence supporting the use of the monoclonal antitumor necrosis factor antibody, infliximab, in active ulcerative colitis and determine its current place in therapy.

EVIDENCE REVIEW

Although faced with initial conflicting data particularly in steroid-refractory patients, two large, placebo-controlled trials have shown that intravenous infliximab induces and maintains clinical improvement in a clinically significant proportion of patients when used with scheduled re-treatment. Infliximab also spares steroids and induces endoscopic remission in moderately ill patients. In fulminant colitis unresponsive to intravenous steroids, one placebo-controlled trial indicates that infliximab is able to prevent colectomy in this patient population. Evidence for cost effectiveness and avoidance of colectomy long term are still lacking.

PLACE IN THERAPY

Infliximab 5 mg/kg induction at 0, 2, and 6 weeks, and every 8 weeks thereafter should be considered in patients with moderately to severely active ulcerative colitis failing medical therapy. Steroid-dependent and steroid-refractory patients also qualify for infliximab therapy.

Cell wall fraction of Enterococcus hirae ameliorates TNF-alpha-induced barrier impairment in the human epithelial tight junction

AIMS

The evaluation of the effects of Enterococcus hirae, an intestinal bacterium in the adjacent mucosa (mucosal bacterium), on tumour necrosis factor-alpha (TNF-alpha)-induced barrier impairment in human epithelial Caco-2 cells.

METHODS AND RESULTS

The filter-grown Caco-2 monolayers were used as an intestinal epithelial model system. In Caco-2 cells, heat-killed E. hirae ATCC 9790(T) suppressed the TNF-alpha-induced barrier impairment and increase in interleukin-8 (IL-8) secretion, but lipase- and mutanolysin-treated E. hirae ATCC 9790(T) did not have these effects. It was demonstrated that lipoteichoic acid (LTA) from E. hirae ATCC 9790(T) is responsible for Caco-2 cells' recovery from TNF-alpha-induced impairments. In addition, Caco-2 cells had the same response to Toll-like receptor 2 (TLR2) ligand, Pam(3)Cys-Ser-(Lys)(4) as they did to LTA. Increased expression of zonula occludens-1 was observed by the addition of E. hirae ATCC 9790(T) to TNF-alpha-treated Caco-2 cells, and decreased expression of myosin light chain kinase was observed by the addition of LTA and Pam(3)Cys-Ser-(Lys)(4); this, in turn, led to barrier enforcement.

CONCLUSIONS

Enterococcus hirae ATCC 9790(T) cell wall fractions, such as LTA, protect against intestinal impairment by regulation of epithelial tight junction via TLR2 signalling.

SIGNIFICANCE AND IMPACT OF THE STUDY

Enterococcus hirae could be useful in the treatment of inflammatory bowel disease, as well as other intestinal disorders.

Inhibition of tumor necrosis factor alpha secretion in rat Kupffer cells by siRNA: in vivo efficacy of siRNA-liposomes

Tumor necrosis factor alpha (TNF-alpha), a pro-inflammatory cytokine, plays a key role in the pathogenesis of many inflammatory diseases, including alcoholic liver disease. In the liver, Kupffer cells are the primary source of the cytokine. Obliteration of Kupffer cells or neutralization of TNF-alpha by anti-TNF-alpha antibody or by an antisense oligonucleotide prevents ethanol-mediated liver damage. In this study, we report the identification of yet another highly efficacious gene-silencing molecule, the short interfering RNA (siRNA), SSL3, against TNF-alpha. The efficacies of various siRNA duplexes were tested against TNF-alpha mRNA in primary cultures of rat Kupffer cells. SSL3 (25 nM) inhibited lipopolysaccharide (LPS)-induced secretion of TNF-alpha by 55% (p<0.005) with a proportionate reduction in TNF-alpha mRNA; the inhibitory effect lasted for at least 96 h. Four nucleotide mismatches to SSL3 completely abolished the inhibitory effects of SSL3, suggesting the sequence specificity of the siRNA. Further, the in vivo efficacy of SSL3 was assessed following the i.v. administration of two doses (140 microg/kg body weight/day for 2 days) of liposome-encapsulated SSL3. The LPS-induced TNF-alpha secretion was inhibited by >60% (p<0.05) by SSL3 pre-treatment. These data demonstrate the identification of an siRNA against TNF-alpha, which, as a liposomal formulation, has therapeutic potential in the treatment of inflammatory diseases mediated by TNF-alpha.

Enterovesical Fistulas Secondary to Crohn's Disease: Medical versus Surgical Therapies

The purpose of this study is to evaluate the efficacy of medical therapies, especially infliximab, to induce remission of enteric fistulas in Crohn's disease (CD). Similarly to CD, chronic transmural inflammation of the bowel, diverticulitis and other pathologies may predispose to the development of fistulas. The risk of fistulization secondary to CD ranges from 17% to 80%. We focused on enterovesical fistulas, which statistically represent 10% of all fistulas secondary to CD.

Material and Methods

In this study we decided to implement a therapeutic program with infliximab 5 mg/kg associated with steroids, which proved to be the most effective method of treatment. From January 2003 to March 2005, we studied 4 patients with CD and enterovesical fistulas. All patients underwent NMR, colonoscopy and cystoscopy combined with fistulography; a therapeutic strategy with cortisone, mesalazine, nutritional therapy and infliximab was established.

Results

No regression was observed; therefore, all the four patients underwent surgery with complete remission of symptoms.

Conclusions

Data reported in literature and the evidence from our experience seem to be contradictory; we concluded therefore that it is mandatory to consider different therapeutic approaches, according to the fistulizing pathways, to such a complex disease, and to formulate some hypothesis that might explain why this treatment was unsuccessful in our patients.

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.

Response and remission are associated with improved quality of life, employment and disability status, hours worked, and productivity of patients with ulcerative colitis

BACKGROUND

Impairment of health-related quality of life, employment, and productivity has been documented in patients with moderate to severe ulcerative colitis.

METHODS

Using prospectively collected data from the Active Ulcerative Colitis Trials 1 and 2, we examined the impact of clinical response or remission, as defined using the Mayo score, on health-related quality of life, employment, disability, productivity, and hours worked per week. These analyses were based on observed data and included all 728 patients, regardless of their randomized treatment group (i.e., placebo and infliximab patients were grouped for analysis). Changes in Inflammatory Bowel Disease Questionnaire (IBDQ) and Medical Outcomes Study 36-Item Short Form (SF-36) scores among nonresponders, responders, and patients in remission were compared. In addition, changes in employment, disability status, productivity, and hours worked per week of patients in clinical remission and patients not in clinical remission were compared.

RESULTS

Ulcerative colitis patients in clinical response or remission had significantly improved IBDQ and SF-36 scores at week 30 compared with those of nonresponders (P<0.001). Among those not employed at baseline, including those receiving disability compensation, greater percentages of patients in remission at week 30 were employed (20.6%) and not receiving disability compensation (58.8%) than were those not in remission (8.3% and 20.0%, respectively; P<0.05 for both comparisons). At week 30, improvements from baseline in productivity and both actual and fully productive hours worked per week were greater for patients in remission compared with those not in remission (P<0.05 for all three comparisons).

CONCLUSIONS

These results confirm the validity of response and remission as defined using the Mayo score.

Adalimumab for maintenance treatment of Crohn's disease: results of the CLASSIC II trial

BACKGROUND

Adalimumab induced clinical remission after four weeks in patients with active Crohn's disease in the CLASSIC I trial.

OBJECTIVE

To evaluate long term efficacy and safety of adalimumab maintenance therapy in Crohn's disease in a follow-on randomised controlled trial (CLASSIC II).

METHODS

In the preceding CLASSIC I trial, 299 patients with moderate to severe Crohn's disease naive to tumour necrosis factor antagonists received induction therapy with adalimumab 40 mg/20 mg, 80 mg/40 mg, or 160 mg/80 mg, or placebo, at weeks 0 and 2. In all, 276 patients from CLASSIC I enrolled in CLASSIC II and received open-label adalimumab 40 mg at weeks 0 (week 4 of CLASSIC I) and 2; 55 patients in remission at both weeks 0 and 4 were re-randomised to adalimumab 40 mg every other week, 40 mg weekly, or placebo for 56 weeks. Patients not in remission at both weeks 0 and 4 were enrolled in an open-label arm and received adalimumab 40 mg every other week. With non-response or flare, these patients could have their dosages increased to 40 mg weekly. Patients in the randomised arm with continued non-response or disease flare could switch to open-label adalimumab 40 mg every other week and again to 40 mg weekly. The primary end point was maintenance of remission (CDAI <150) in randomised patients through week 56.

RESULTS

Of 55 patients randomised at week 4, 79% who received adalimumab 40 mg every other week and 83% who received 40 mg weekly were in remission at week 56, v 44% for placebo (p<0.05). In all, 204 patients entered the open-label arm. Of these, 93 (46%) were in clinical remission at week 56. Adalimumab was generally well-tolerated in all patients.

CONCLUSIONS

Adalimumab induced and maintained clinical remission for up to 56 weeks in patients with moderate to severe Crohn's disease naive to anti-TNF treatment.

Prescribing patterns and awareness of adverse effects of infliximab: a health survey of gastroenterologists

We sought to determine prescribing patterns and awareness of adverse drug reactions to infliximab among gastroenterologists. A questionnaire was developed and mailed to all gastroenterologists in Maryland and Washington, D.C. Ninety-six of 336 (28.6%) gastroenterologists responded; 86% of respondents use infliximab often or sometimes and 48% infuse infliximab on-site. Only 48% of respondents use immunomodulators prior to infusing infliximab. Thirty-three percent of respondents do not prescribe maintenance infliximab. Respondents reported that infusion reactions occur in 12.9% of infliximab infusions. Most respondents order a purified protein derivative prior to starting infliximab. Respondents underestimated the risk of serious infection, death, demyelinating diseases, and malignancy and overestimated the risk of congestive heart failure. We conclude that a substantial number of gastroenterologists underutilize immunomodulators and fail to prescribe maintenance infliximab. Further, respondents were unaware of the frequency of major adverse events associated with infliximab. Education regarding treatment algorithms in CD and infliximab-related side effects is needed.

A randomized, double-blind, placebo-controlled trial of lenalidomide in the treatment of moderately severe active Crohn's disease

BACKGROUND

Therapy targeted at tumour necrosis factor-alpha has an established role in Crohn's disease. Lenalidomide, an analogue of thalidomide, is an oral immunomodulatory agent with powerful antitumour necrosis factor-alpha properties. It is licensed for myeloma and myelodysplastic syndrome. Based upon reports of thalidomide efficacy, lenalidomide was evaluated in Crohn's disease.

AIM

To evaluate the efficacy and safety of lenalidomide in subjects with moderately severe active Crohn's disease.

METHODS

In a multicentre, double-blind, placebo-controlled parallel group study 89 subjects were randomized to lenalidomide 25 mg daily, 5 mg daily or placebo. Subjects were treated for 12 weeks. The primary end point was a 70-point reduction in Crohn's Disease Activity Index.

RESULTS

The overall clinical response rate was not significantly different between the three groups: lenalidomide 25 mg 26%, lenalidomide 5 mg 48% and placebo 39%. Lenalidomide was generally well tolerated with only one serious adverse event, a deep vein thrombosis, being attributed to treatment.

CONCLUSION

Lenalidomide, an oral agent with antitumour necrosis factor-alpha properties, was not effective in active Crohn's disease in contrast to reports of benefit from thalidomide. The reasons for this lack of efficacy are speculative, other physiological activities may offset its action on inflammatory cytokines, or its antitumour necrosis factor-alpha action without apoptosis may be insufficient for activity in Crohn's disease.

Mode of function of biological anti-TNF agents in the treatment of inflammatory bowel diseases

TNF-alpha has been identified as a major mediator in the pathophysiology of inflammation. Anti-TNF agents, either as a neutralising antibody or a soluble TNF receptor, have markedly influenced the clinical management of several chronic inflammatory disorders. Whereas it seems likely that neutralisation of soluble and membrane-bound TNF might be a key mechanism of any anti-TNF agent, the potential of the anti-TNF antibody infliximab to induce lymphocyte/monocyte apoptosis in Crohn's disease has been considered an additional important mechanism. Other potential mode of actions include induction of the anti-inflammatory cytokines IL-10 or TGF-beta via retrograde signalling or induction of a certain subset of regulatory T cells. Certolizumab, a pegylated fully human anti-TNF monoclonal antibody also effective in Crohn's disease, lacks the capacity to induce apoptosis. Therefore, the capacity to induce apoptosis and neutralisation of TNF alone are insufficient to explain clinical efficacy of anti-TNF agents in human inflammatory bowel diseases.

The role of TNFalpha in ulcerative colitis

Standard of care for ulcerative colitis involves long-term pharmacotherapy or colectomy. Approximately 20% to 30% of patients eventually require a colectomy because patients either do not respond or cannot tolerate the currently available pharmacotherapies. Advances in our knowledge of the pathophysiology of ulcerative colitis have highlighted the importance of cytokines such as tumor necrosis factor alpha (TNFalpha) in the inflammatory process. TNFalpha is a proinflammatory mediator that plays an integral role in the pathogenesis of inflammatory bowel disease. In addition, mounting evidence indicates a genetic association between TNFalpha and ulcerative colitis. Furthermore, increased TNFalpha levels have been demonstrated in studies of patients with ulcerative colitis. TNFalpha is likely an important component in the pathophysiology of ulcerative colitis, and thus agents targeting TNFalpha in ulcerative colitis have been studied. Recent randomized controlled trials have confirmed that biologic anti-TNFalpha therapy is effective in ulcerative colitis. Soluble TNFalpha receptors or biologic agents that suppress or inhibit TNFalpha production may also show therapeutic promise.

Bacterial peptidoglycan breaks down intestinal tolerance via mast cell activation: the role of TLR2 and NOD2

Intestinal microbes are believed to be involved in the pathogenesis of inflammatory bowel disease. Microbes and their products are generally well tolerated by intestinal epithelial cells in the intestinal tract of healthy individuals. It is of significance to understand what breaks down the established tolerance leading to intestinal barrier dysfunction and intestinal inflammation. T84 monolayer transported peptidoglycan (PGN) was determined by enzyme-linked immune assay. Mast cell line HMC-1 cell activation in response to PGN stimulation was observed with electron microscopy and measurement of histamine release. T84 monolayer barrier function was determined by recording the transepithelial electric resistance (TER) and measuring the permeability in response to PGN-induced HMC-1 cell activation. Expression of Toll-like receptor (TLR) 2 and nucleotide-binding oligomerization domain (NOD) 2 were determined by immunocytochemistry, real-time reverse transcription (RT)-PCR and Western blot. Exposure to PGN alone did not alter TER and permeability of T84 monolayers. T84 monolayers transported PGN from the apical chamber to the basal chamber of transwell system. TLR2 expressed on the surface of HMC-1 cells. HMC-1 cells absorbed PGN. HMC-1 cells released histamine in response to the PGN stimulation, which was blocked by pretreatment with antibodies or small interfering RNA against TLR2 or NOD2. In a co-culture system, T84 monolayer transported PGN activated HMC-1 cells and increased the horseradish peroxidase flux. TLR2 mediated the PGN-absorption in HMC-1 cells. Blockade of TLR2 or NOD2 abolished PGN-induced HMC-1 cell activation and T84 monolayer barrier dysfunction. T84 monolayer transported PGN activates HMC-1 cells to release chemical mediators to induce T84 monolayer dysfunction that are mediated by TLR2 and NOD2.

Adalimumab induction therapy for ulcerative colitis with intolerance or lost response to infliximab: An open-label study

AIM: To evaluate the efficacy of adalimumab induction therapy in patients with ulcerative colitis who previously responded to infliximab and then lost response or became intolerant.

METHODS: Ten patients with ulcerative colitis were enrolled in a 4-wk open-label trial. The patients received a loading dose of 160 mg adalimumab at wk 0 followed by 80 mg at wk 2. The primary efficacy measure was clinical improvement at wk 4, as defined by a decrease in clinical activity index (CAI) of more than 4.

RESULTS: Four of 10 patients (40%) benefited from subsequent adalimumab therapy; one patient achieved remission (CAI < 4) and 3 had clinical improvement at wk 4. 6 patients had no response (60%); 2 of 6 (33.3%) subsequently underwent colectomy. This was accompanied by a decrease in median CRP concentration from 16.8 mg/mL at baseline to 3.85 mg/mL at wk 4, excluding two patients who underwent colectomy after two infusions of adalimumab. Among the 6 patients with severe colitis (CAI > 12) at baseline, none achieved remission and only one patient had clinical improvement at wk 4.

CONCLUSION: The small advantage of adalimumab in patients with mild to moderate ulcerative colitis and lost response or intolerance to infliximab needs to be confirmed in randomised, double-blind, placebo-controlled trials.

Melphalan reduces the severity of experimental colitis in mice by blocking tumor necrosis factor-alpha signaling pathway

Melphalan is an alkylating agent, which is commonly used as an antineoplastic drug. Its cytostatic effect can be realized in humans in the dose range of 0.6-1.4 mg/kg body weight. However, previously it was shown that in the case of gradual dose decrease, the number of targets for alkylation was also reduced and the drug lost its cytostatic properties switching to cell growth modifier. It has been postulated that application of alkylating agents in such ultra-low concentrations (50- to 100-fold lower than cytostatic ones) may result in a beneficial effect in the therapy of diseases associated with mucosa inflammation. The aim of the article was to investigate the effect of ultra-low doses of melphalan in the murine experimental colitis induced by the replacement of drinking water with 5% solution of dextran sulphate sodium (DSS). Daily administration of melphalan (25 microg/kg body weight) markedly reduced the severity of DSS-colitis as determined by clinical and quantitative histological criteria. Both systemic and local anti-inflammatory effects of melphalan have been observed. The possible mechanisms of the beneficial effect of the drug have been discussed.

A new 4-(2-methylquinolin-4-ylmethyl)phenyl P1′ group for the β-amino hydroxamic acid derived TACE inhibitors

A new P1' group for TACE inhibitors was identified by eliminating the oxygen atom in the linker of the original 4-(2-methylquinolin-4-ylmethoxy)phenyl P1' group. Incorporation of this 4-(2-methylquinolin-4-ylmethyl)phenyl group onto different beta-aminohydroxamic acid cores provided compound 18, which demonstrated potent porcine TACE (p-TACE) and human whole blood activity, excellent PK properties, and good selectivity against a variety of MMPs.

The effects of infliximab therapy on health-related quality of life in ulcerative colitis patients

OBJECTIVES

The impact of infliximab induction and maintenance therapy on health-related quality of life (HRQL) was evaluated in patients with ulcerative colitis (UC).

METHODS

In two placebo-controlled, double-blind studies (the Active Ulcerative Colitis Trials 1 and 2 [ACT 1 and 2]), 728 patients were randomized to placebo or infliximab 5 mg/kg or 10 mg/kg. Infusions were administered at weeks 0, 2, 6, and every 8 wk thereafter, up to week 22 (ACT 2) or 46 (ACT 1). Changes in Inflammatory Bowel Disease Questionnaire (IBDQ) and Medical Outcomes Study 36-Item Short Form Health Survey physical and mental component summary (PCS and MCS, respectively) scores were analyzed.

RESULTS

Baseline scores for the pooled patient population indicated substantial impairment in HRQL. Improvement at week 8 in the total IBDQ score was significantly greater in the infliximab 5-mg/kg (40, P < 0.001) and 10-mg/kg (36, P < 0.001) groups compared with the placebo group (28). Improvement at week 8 was also significantly greater in the infliximab 5- and 10-mg/kg groups for the PCS (6.8 and 5.9, respectively) and MCS (5.9 and 6.4, respectively) compared with placebo (PCS = 3.7, MCS = 3.0, P < 0.01 for all comparisons). Continued benefit was seen at weeks 30 and 54 with infliximab maintenance therapy (P < 0.001 for all comparisons). Improvement in total IBDQ score correlated significantly (P < 0.001) with improvement in both PCS and MCS scores, and Mayo score.

CONCLUSIONS

Infliximab therapy substantially improved HRQL in patients with UC. This benefit was sustained through 1 yr with maintenance infliximab therapy.

Extracorporeal elimination of TNF-alpha-producing CD14(dull)CD16(+) monocytes in leukocytapheresis therapy for ulcerative colitis

BACKGROUND

In recent years leukocytapheresis using a leukocyte removal filter (known as lymphocytapheresis, LCAP) has been applied to the treatment of various autoimmune diseases including ulcerative colitis (UC). In the present study we aimed to clarify how LCAP therapy modifies inflammatory responses by modulating circulating TNF-alpha-producing monocytes.

METHODS

Mononuclear cells were obtained from blood before and after the first treatment, and the expression profiles of various immune cells (naive versus. memory, regulatory CD4(+)CD25(bright) versus non-regulatory CD4(+)CD25(-) T cells, and CD14(+)CD16(-) versus CD14(dull)CD16(+) monocytes) were assessed. To evaluate immunological differences between CD14(+)CD16(-) and CD14(dull)CD16(+) monocytes, the expression of TNF-alpha, IL-6, IL-12, IL-10, IL-18, surface toll-like receptor 2 (TLR2), TLR4, and other activation markers including HLA-DR, CD80 and CD86, as well as cytokine profiles, were analyzed.

RESULTS

LCAP treatment selectively removed CD14(dull)CD16(+) monocytes, which preferentially produce TNF-alpha and IL-12 and express HLA-DR, CD80, CD86, and TLR2, compared with the major fraction of CD14(+)CD16(-) monocytes, which conversely produce a higher amount of IL-10. In addition, the CD4(+)CD45RO(+)CD62L(-)/CD4(+)CD45RO(+)CD62L(+) ratio was significantly lower after LCAP therapy. However, the CD4(+)CD25(bright)/total CD4(+) ratio did not change.

CONCLUSIONS

The present findings revealed the real target of proinflammatory CD14(dull)CD16(+) monocytes removed during LCAP treatment of UC and that LCAP might be used as an extracorporeal anti-TNF-alpha therapy, expanding the clinical applications of this procedure to include the treatment of Crohn's disease.

Efficacy and safety of thalidomide in children and young adults with intractable inflammatory bowel disease: long-term results

BACKGROUND

Anti-tumour necrosis factor-alpha antibodies are useful for the treatment of refractory Crohn's disease and ulcerative colitis. Thalidomide is another agent with tumour necrosis factor-alpha suppressive properties.

AIM

To investigate the long-term efficacy and safety of thalidomide in a group of children and young adults with refractory inflammatory bowel disease.

METHODS

Twenty-eight patients with refractory moderate-severe inflammatory bowel disease (19 Crohn's disease, 9 ulcerative colitis) received thalidomide 1.5-2.5 mg/kg/day. Patients were assessed at baseline, at weeks 2, 4, 8 and 12, and then every 12 weeks by patient's diary, physical examinations, laboratory analyses and scoring on activity indexes. Primary outcomes were: (i) efficacy in inducing remission; and (ii) efficacy in maintaining remission.

RESULTS

Remission was achieved with thalidomide in 21 of 28 (75%) patients (17 with Crohn's disease, 4 with ulcerative colitis). Mean duration of remission was 34.5 months. Sixteen of 20 (80%) patients suspended steroids. Reversible neuropathy occurred in seven of 28 (25%) patients, but only with cumulative doses over 28 g. Other side effects requiring thalidomide suspension were vertigo/somnolence (one of 28), and agitation/hallucinations (one of 28).

CONCLUSIONS

Thalidomide seems to be effective in inducing long-term remission in children and adolescents with intractable inflammatory bowel disease. Neuropathy is the main adverse effect, but appears to be cumulative dose-dependent, thus allowing long-term remission before drug suspension.

Effect of the anti-tumor necrosis factor-alpha antibody infliximab on the ex vivo mucosal matrix metalloproteinase-proteolytic phenotype in inflammatory bowel disease

BACKGROUND

Previous studies have shown an upregulation of matrix metalloproteinases (MMPs) in intestinal tissue of patients with inflammatory bowel disease (IBD) and significant clinical improvement after administration of the anti-TNF-a antibody infliximab. The aims of our study were to determine expression and secretion of MMP-1, -2, -3, -9, and their inhibitors TIMP-1, -2 by IBD versus control intestinal mucosa ex vivo and to assess the regulatory capacity by infliximab of the proteolytic phenotype.

METHODS

Intestinal mucosal explants from 20 IBD and 15 control patients were cultured with or without infliximab and/or the T-cell activator pokeweed mitogen (PWM). Explants and culture supernatants were analyzed for MMPs, TIMPs, and TNF-alpha protein, activity and/or mRNA levels. All patients were genotyped for functional TNF-alpha, MMP, and TIMP single nucleotide polymorphism (SNP) loci.

RESULTS

Expression of MMP and TIMP protein/activity in basal medium was higher in IBD versus control explants. Dependent on genotype at SNP loci, infliximab downregulated MMP-1, -3, and -9 relative to TIMP-1 and -2 and also decreased MMP-1 and -3 activities, while PWM enhanced these levels, partly counteracted again by infliximab. The expression of MMP-2 relative to TIMP did not change by treatment with infliximab and/or PWM.

CONCLUSIONS

The high expression of MMPs in patients with IBD suggests a role for these proteinases in the pathogenesis of this disease. Infliximab seems to induce a genotype-associated matrix protective phenotype, which may contribute to the observed therapeutic efficacy of this drug in IBD, particularly at the mucosal surface.

Polymorphisms of tumor necrosis factor-alpha but not MDR1 influence response to medical therapy in pediatric-onset inflammatory bowel disease

AIM

We investigated the contribution of variants of tumour necrosis factor (TNF)-alpha and MDR1 genes in the predisposition and response to medical therapy in a large pediatric cohort of patients with Crohn disease (CD) and ulcerative colitis (UC).

PATIENTS AND METHODS

In this study, 200 patients with CD, 186 patients with UC, 434 parents (217 trios), and 347 healthy unrelated controls were investigated. Single-nucleotide polymorphisms -G308A and -C857T of the TNF-alpha gene and C3435T of the MDR1 gene were investigated and correlated with clinical subphenotypes and efficacy of medical therapy.

RESULTS

The frequency of the -308A allele of the TNF-alpha gene was significantly increased in both patients with CD (15%; odds ratio [OR] = 2.79; P < 0.01) and patients with UC (11%; OR = 1.96; P < 0.003) compared with controls (6%). Carriers of this allele were 27% in CD (OR = 2.94; P < 0.01) and 19% in UC (OR = 1.86; P = 0.015) compared with 11% in healthy controls. No significant difference was found for both the -C857T and C3435T single-nucleotide polymorphisms. With the genotype/phenotype analysis, no correlation in patients with UC with the MDR1 gene was found. CD carriers of the -308A allele had a higher frequency of surgical resection (35% vs 20%; OR = 2.1; P = 0.035) and more frequent resistance to steroids (22% vs 8%; OR = 0.29; P = 0.032) compared with noncarriers. These findings were confirmed by stepwise logistic regression.

CONCLUSIONS

In our pediatric cohort, the promoter -308A polymorphism of TNF-alpha but not the MDR1 gene is significantly involved in the predisposition to both CD and UC. This polymorphism carries a significant reduction in response to steroid therapy, probably leading to a more frequent need for surgical resection.

Certolizumab pegol: an evidence-based review of its place in the treatment of Crohn's disease

INTRODUCTION

Crohn's disease (CD) is a chronic inflammatory bowel disease characterized by a relapsing/remitting course with transmural inflammation of potentially any section of the digestive tract. Certolizumab pegol (CZP) is a pegylated Fc-free Fab' fragment of a humanized anti-TNF-alfa monoclonal antibody that is in development for clinical use in CD.

AIMS

To review the available data with CZP in CD, to investigate its possible place in therapy.

EVIDENCE REVIEW

Available studies suggest that CZP has the potential to achieve and maintain clinical response and remission in moderate to severe CD, and to improve quality of life compared with placebo. Further studies with CZP are also ongoing.

PLACE IN THERAPY

Although only suggested by currently available studies, successive clinical practice and further ongoing trials may confirm a positive role for CZP as a new anti-TNF treatment in CD. The impact on clinical management or on resources cannot be estimated until the results from all phase III clinical trials are available and the price is determined.

The role of anti-tumor necrosis factor-alpha therapy in Pyoderma gangrenosum associated with inflammatory bowel disease

Pyoderma gangrenosum (PG) is an ulcerative neutrophilic dermatosis seen in 1-5% of patients with inflammatory bowel disease (IBD). The pathogenesis of PG remains unclear, but may be related to abnormal T-cell responses and production of tumor necrosis factor (TNF)-alpha, a powerful proinflammatory cytokine. Although their use is not supported by appropriately controlled trials, corticosteroids and systemic immunosuppressants are the classical cornerstones of treatment of PG, against which they have a nonspecific effect. Successful curative or symptomatic treatment of associated disorders may lead to an improvement in PG. A new era for the management of chronic inflammatory disease began with the advent of biotherapies and particularly anti-TNFalpha therapy, which allows for a specific intervention in the immune cascade. Anti-TNFalpha therapy has improved and broadened the therapeutic options for IBD and, therefore, has brought new perspectives to management of the extra-intestinal manifestations of this disorder, including PG. To date, infliximab, etanercept, and adalimumab have been used in the treatment of PG. Published data have demonstrated that infliximab is highly effective in the treatment of PG, whether associated with IBD or not. This treatment is generally well tolerated, even as long-term therapy. However, rare and serious complications have been reported. Although infliximab is a costly drug, its use should be considered for patients with PG and particularly with corticosteroid-refractory PG associated with IBD. Additional comparative long-term studies are needed to determine the long-term efficacy and safety of anti-TNFalpha therapy and define its role in the management of PG, with or without accompanying IBD.

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.

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.

Proteasome-mediated degradation of IkappaBalpha and processing of p105 in Crohn disease and ulcerative colitis

Enhanced NF-kappaB activity is involved in the pathology of both forms of inflammatory bowel disease (IBD), Crohn disease (CD) and ulcerative colitis (UC). Here we analyzed the mechanism of proteasome-mediated NF-kappaB activation in CD and UC. Our studies demonstrate that the subunit composition and the proteolytic function of proteasomes differ between UC and CD. High expression of the immunoproteasome subunits beta1i and beta2i is characteristic of the inflamed mucosa of CD. In line with this, we found enhanced processing of NF-kappaB precursor p105 and degradation of inhibitor of NF-kappaB, IkappaBalpha, by immunoproteasomes isolated from the mucosa of CD patients. In comparison with healthy controls and CD patients, UC patients exhibited an intermediate phenotype regarding the proteasome-mediated processing/degradation of NF-kappaB components. Finally, increased expression of the NF-kappaB family member c-Rel in the inflamed mucosa of CD patients suggests that p50/c-Rel is important for IFN-gamma-mediated induction of immunoproteasomes via IL-12-driven Th1 responses. These findings suggest that distinct proteasome subunits influence the intensity of NF-kappaB-mediated inflammation in IBD patients.

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

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

Novel strategies for the treatment of inflammatory bowel disease: Selective inhibition of cytokines and adhesion molecules

The etiology of inflammatory bowel disease (IBD) has not yet been clarified and immunosuppressive agents which non-specifically reduce inflammation and immunity have been used in the conventional therapies for IBD. Evidence indicates that a dysregulation of mucosal immunity in the gut of IBD causes an overproduction of inflammatory cytokines and trafficking of effector leukocytes into the bowel, thus leading to an uncontrolled intestinal inflammation. Such recent advances in the understanding of the pathogenesis of IBD created a recent trend of novel biological therapies which specifically inhibit the molecules involved in the inflammatory cascade. Major targets for such treatment are inflammatory cytokines and their receptors, and adhesion molecules. A chimeric anti-TNF-α monoclonal antibody, infliximab, has become a standard therapy for CD and it is also likely to be beneficial for UC. Several anti-TNF reagents have been developed but most of them seem to not be as efficacious as infliximab. A humanized anti-TNF monoclonal antibody, adalimumab may be useful for the treatment of patients who lost responsiveness or developed intolerance to infliximab. Antibodies against IL-12 p40 and IL-6 receptor could be alternative new anti-cytokine therapies for IBD. Anti-interferon-γ and anti-CD25 therapies were developed, but the benefit of these agents has not yet been established. The selective blocking of migration of leukocytes into intestine seems to be a nice approach. Antibodies against α4 integrin and α4β7 integrin showed benefit for IBD. Antisense oligonucleotide of intercellular adhesion molecule 1 (ICAM-1) may be efficacious for IBD. Clinical trials of such compounds have been either recently reported or are currently underway. In this article, we review the efficacy and safety of such novel biological therapies for IBD.

Drug Insight: antagonists of tumor-necrosis factor-α in the treatment of inflammatory bowel disease

In the past decade, advances in the understanding of the pathogenesis of inflammatory bowel disease have permitted the development of agents directed against rational therapeutic targets. In particular, various antagonists of tumor-necrosis factor-alpha have been developed. These include infliximab, adalimumab, certolizumab (CDP870), CDP571, etanercept, and onercept. Clinical trials of these agents have demonstrated varying degrees of clinical efficacy. The use of these agents can be limited by infection, immunogenicity, acute infusion reactions, delayed hypersensitivity reactions, and autoimmune phenomena. This review provides insights into the use of antagonists of tumor-necrosis factor-alpha for the treatment of inflammatory bowel disease.

Infliximab and ulcerative colitis

Tumour necrosis factor (TNF)-alpha is an inflammatory cytokine that plays a main role in the inflammatory process underlying inflammatory bowel disease (IBD). Despite the fact that the cytokine profiles associated with ulcerative colitis (UC) and Crohn's disease (CD) are classically considered different (a Th2 pattern in UC and a Th1 pattern in CD), there are several evidences in vitro and in vivo that TNF-alpha has an important role in UC. For this reason, infliximab, the chimeric monoclonal antibody to TNF-alpha, has been evaluated in the therapy of UC. The drug has been evaluated in different clinical settings both in adults and in children: in moderate-severe steroid-dependent UC, in severe refractory UC as rescue therapy, in active non-steroid-refractory UC, in resistant pouchitis and in maintenance of moderate-severe UC responsive to infliximab. On the basis of the randomised controlled trials (RCTs), it is possible to draw the following conclusions for adults: infliximab seems active in severe steroid-refractory UC, allowing colectomy to be spared even if further controlled trials are needed with a larger sample of patients adopting strict and well-defined inclusion criteria. The drug seems active in inducing remission after 8 weeks in steroid-refractory patients, in patients taking steroids (even if it is not clear at which dosage of steroid dependence the drug is more active) and also in patients failing aminosalicylates therapy. The long-term response of infliximab in comparison to placebo in these subgroups of patients is not clinically impressive even if it is statistically significant. Further trials are warranted in order to establish the role of infliximab in steroid-dependent UC (defined with clear criteria), in maintaining remission after severe UC, in non-steroid-dependent moderate-severe UC and in refractory pouchitis. For children it is not possible to draw the same conclusions, due to a lack of RCTs, despite the encouraging data coming from open studies, mainly in steroid-refractory UC.

Molecular mechanism of tumor necrosis factor-alpha modulation of intestinal epithelial tight junction barrier

A TNF-alpha-induced increase in intestinal epithelial tight junction (TJ) permeability has been proposed to be an important proinflammatory mechanism contributing to intestinal inflammation in Crohn's disease and other inflammatory conditions. Previous studies from our laboratory suggested that the TNF-alpha-induced increase in intestinal TJ permeability was mediated by an increase in myosin light chain kinase (MLCK) protein expression. However, the molecular mechanisms that mediate the TNF-alpha increase in intestinal TJ permeability and MLCK protein expression remain unknown. The purpose of this study was to delineate the intracellular and molecular mechanisms that mediate the TNF-alpha-induced increase in intestinal TJ permeability; using an in vitro intestinal epithelial model system consisting of filter-grown Caco-2 intestinal epithelial monolayers. To examine the molecular mechanisms involved in the TNF-alpha regulation of intestinal TJ barrier, we identified and cloned for the first time a functionally active MLCK promoter region. TNF-alpha treatment of filter-grown Caco-2 monolayers transfected with plasmid vector containing the MLCK promoter region produced an increase in MLCK promoter activity and MLCK transcription. The TNF-alpha-induced increase in MLCK transcription corresponded to a sequential increase in MLCK protein expression, MLCK activity, and Caco-2 TJ permeability. The TNF-alpha-induced increase in MLCK promoter activity was mediated by NF-kappaB activation, and the inhibition of NF-kappaB activation prevented the TNF-alpha-induced increase in promoter activity and the subsequent increase in MLCK protein expression and Caco-2 TJ permeability. The TNF-alpha-induced activation of MLCK promoter was mediated by binding of the activated NF-kappaB p50/p65 dimer to the downstream kappaB binding site (-84 to -75) on the MLCK promoter region; deletion of the kappaB binding site prevented the TNF-alpha increase in promoter activity. Additionally, siRNA silencing of NF-kappaB p65 also prevented the TNF-alpha increase in MLCK promoter activity. In conclusion, our findings indicated that the TNF-alpha-induced increase in intestinal epithelial TJ permeability was mediated by NF-kappaB p50/p65 binding and activation of the MLCK promoter. NF-kappaB p50/p65 activation of the MLCK promoter then leads to a stepwise increase in MLCK transcription, expression and activity, and MLCK-mediated opening of the intestinal TJ barrier.

Oral p38 mitogen-activated protein kinase inhibition with BIRB 796 for active Crohn's disease: a randomized, double-blind, placebo-controlled trial

BACKGROUND & AIMS

The p38 mitogen-activated protein kinase (MAPK) regulates the expression of proinflammatory cytokines, which play a critical role in the pathophysiology of Crohn's disease (CD). This study investigated the efficacy and safety of BIRB 796, a highly potent inhibitor of p38 MAPK, in chronic active CD.

METHODS

In a multicenter, multinational trial, 284 patients with moderate to severe CD were randomized to receive placebo, or 10, 20, 30, or 60 mg of BIRB 796 twice daily for 8 weeks. Clinical endpoints were based on standard safety assessments, CD Activity Index, C-reactive protein levels, and quality of life (Inflammatory Bowel Disease Questionnaire). In a substudy, the Crohn's Disease Endoscopic Index of Severity and histologic results of biopsy specimens were assessed.

RESULTS

No clinical efficacy (primary end point, clinical remission; secondary end point, clinical response; Inflammatory Bowel Disease Questionnaire; Crohn's Disease Endoscopic Index of Severity) was seen for BIRB 796 in comparison with placebo. A significant, dose-dependent decrease of C-reactive protein level was observed transiently after BIRB 796 after 1 week with a return to baseline level over time. The incidence of adverse events was comparable between all treatment groups, with the exception of a mild increase of transaminase levels that was seen more frequently in the BIRB 796 groups. Geographic center effects were observed with Russian centers producing distinctly higher remission and response rates and lower adverse event rates than in other countries in both placebo and active treatment groups.

CONCLUSIONS

There was no evidence for clinical efficacy of BIRB 796 in CD. A remarkable difference in the course of CD exists between Russia and non-Russian centers.

Human anti-tumor necrosis factor monoclonal antibody (adalimumab) in Crohn's disease: the CLASSIC-I trial

BACKGROUND & AIMS

Tumor necrosis factor blockade has been shown to be an effective treatment strategy in Crohn's disease (CD). Adalimumab is a human immunoglobulin G1 (IgG(1)) monoclonal antibody targeting tumor necrosis factor (TNF). A randomized, double-blind, placebo-controlled, dose-ranging trial was performed to evaluate the efficacy of adalimumab induction therapy in patients with CD.

METHODS

A total of 299 patients with moderate to severe CD naive to anti-TNF therapy were randomized to receive subcutaneous injections at weeks 0 and 2 with adalimumab 40 mg/20 mg, 80 mg/40 mg, or 160 mg/80 mg or placebo. The primary endpoint was demonstration of a significant difference in the rates of remission at week 4 (defined as a Crohn's Disease Activity Index score <150 points) among the 80 mg/40 mg, 160 mg/80 mg, and placebo groups.

RESULTS

The rates of remission at week 4 in the adalimumab 40 mg/20 mg, 80 mg/40 mg, and 160 mg/80 mg groups were 18% (P = .36), 24% (P = .06), and 36% (P = .001), respectively, and 12% in the placebo group. Adverse events occurred at similar frequencies in all 4 treatment groups except injection site reactions, which were more common in adalimumab-treated patients.

CONCLUSIONS

Adalimumab was superior to placebo for induction of remission in patients with moderate to severe Crohn's disease naive to anti-TNF therapy. The optimal induction dosing regimen for adalimumab in this study was 160 mg at week 0 followed by 80 mg at week 2. Adalimumab was well tolerated.

From immunogenic mechanisms to novel therapeutic approaches in inflammatory bowel disease

Crohn's disease (CD) and ulcerative colitis (UC) are the two most common forms of chronic inflammatory bowel disease (IBD). The etiology of IBD is still unclear and should be considered as multi-factorial according to recent studies. Genetic factors seem to play a pathogenetic role as well as environmental, infectious and immulogical factors. Substantial progress, however, has been made in the understanding of the pathogenesis of IBD during the past years persuing the view, that IBD could result from disturbances of the intestinal barrier and a pathologic activation of the intestinal immune response towards luminal, bacterial antigens. This paradigm has led to the identification of key players of the intestinal immune system, which represent promising targets for novel therapeutic approaches. The objective of this chapter is to provide an overview over recent advances in the elucidation of the intestinal immune system in IBD and novel therapeutic approaches that have been derived from these results. Molecular biological techniques have revealed, that many of the established conventional antiinflammatory drugs such as salicylic acids, steroids or immunuosuppressants act at the same molecules that are the target for modern biologicals, i.e., the cytokine TNF or the transcription factor NFkappaB. This chapter, however, focusses on novel experimental approaches such as recombinant antiinflammatory cytokines, neutralizing antibodies or antisense oligonucleotides.