Change in erythrocyte mean corpuscular volume during combination therapy with azathioprine and infliximab is associated with mucosal healing: a post hoc analysis from SONIC.

BACKGROUND: The adequacy of exposure of purine analogs as measured by 6-thioguanine nucleotides concentrations in the setting of combination therapy remains poorly understood. The aim of this study was to investigate the relationship between the mean corpuscular volume (MCV) value (as a surrogate marker of 6-thioguanine nucleotides concentration) and Crohn's disease outcomes in the setting of combination therapy with infliximab. METHODS: The SONIC trial was a randomized controlled trial comparing infliximab to azathioprine and to infliximab plus azathioprine in 508 Crohn's disease patients. An increase of at least 7 femtoliter (fL) of the MCV (ΔMCV) was used for statistical analysis. RESULTS: At week 26, the mean increase of MCV was similar among patients treated with azathioprine alone (mean of 7.9 fL) or in combination with infliximab (mean of 8.5 fL). In the azathioprine group, 63.6% of patients with ΔMCV >7 were in steroid-free clinical remission at week 26 as compared with 33.3% of patients without ΔMCV >7 (P = 0.0046). In the combination therapy group, ΔMCV above 7 was associated with mucosal healing (75.0% for ΔMCV >7 versus 47.1% for ΔMCV <7, P = 0.0172) but not with steroid-free clinical remission. Patients with a ΔMCV above 7 were more likely to have infliximab trough level above 3 µg/mL at week 30 (68.4% versus 38.8% for ΔMCV <7, P = 0.0032). CONCLUSIONS: These results suggest that ΔMCV above 7 (which is a surrogate for a higher 6-thioguanine nucleotides concentration) leads to improved Crohn's disease outcomes, even when combined with infliximab. It also suggests the possibility that a lower azathioprine exposure might be less effective in combination therapy.

Validation of endoscopic activity scores in patients with Crohn's disease based on a post hoc analysis of data from SONIC.

BACKGROUND & AIMS: Mucosal healing might alter midterm and long-term outcomes of patients with Crohn's disease (CD) and has become an important end point in clinical trials. However, the minimal degree of mucosal improvement (endoscopic response) required to alter midterm outcomes is not known. We aimed to determine the best definition of endoscopic response by evaluating data on the Simple Endoscopic Score for Crohn's Disease (SES-CD) and the Crohn's Disease Endoscopic Index of Severity (CDEIS) from the Study of Biologic and Immunomodulator Naive Patients in Crohn's Disease (SONIC trial). METHODS: We analyzed data from 172 patients who participated in the SONIC trial, were found to have endoscopic lesions at baseline, and underwent a second endoscopic examination at week 26 of treatment with infliximab, azathioprine, or both. Mucosal healing was defined as absence of ulcers. A central reader calculated SES-CD and CDEIS results. Different cutoff values were set for endoscopic response based on the SES-CD or CDEIS. The diagnostic ability of these different cutoff values was evaluated using receiver operating characteristic (ROC) curves, positive likelihood ratios (PLR), and negative likelihood ratios (NLR). Corticosteroid-free clinical remission (CFREM) at week 50 was used as a binary classifier. RESULTS: Based on analyses of ROC curves, PLR, and NLR, endoscopic response was defined as a decrease from baseline in SES-CD of at least 50%. At week 26, mucosal healing and endoscopic response were achieved in 48% and 65% of patients, respectively. Mucosal healing at week 26 was associated with CFREM at week 50, with 56% sensitivity, 65% specificity, a PLR of 1.60, and an NLR of 0.67. Endoscopic response at week 26 was associated with CFREM at week 50, with 74% sensitivity, 48% specificity, a PLR of 1.42, and an NLR of 0.54. Endoscopic response, defined as a decrease from baseline in CDEIS of at least 50%, yielded similar results. CONCLUSIONS: In patients with CD, mucosal healing and endoscopic response (defined as a decrease from baseline in SES-CD or CDEIS of at least 50%) at week 26 of treatment identified those most likely to be in CFREM at week 50. The ability of the proposed endoscopic response cutoff value to predict midterm CFREM should be validated in an independent, prospective cohort. Its correlation with changes in long-term disease progression still needs to be demonstration. ClinicalTrials.gov, Number: NCT00094458.

Maternal inflammatory bowel disease has short and long-term effects on the health of their offspring: a multicenter study in Israel.

BACKGROUND: There are concerns about the effect of inflammatory bowel diseases (IBD) on fertility, pregnancy and pregnancy outcomes, but no long-term data on the health of offspring born to IBD mothers. The aims were to assess the short- and long-term effects of maternal IBD on the morbidity and development of their offspring. METHODS: Female IBD patients and controls completed questionnaires on their pregnancy outcome, and their offspring's short- and long-term health and development. RESULTS: IBD and control mothers (159 and 175, respectively) were recruited. Medical data of 412 IBD and 417 control offspring were recorded. IBD mothers had significantly more singleton pregnancies, their offspring's birth weight was significantly lower, and they breastfed significantly less compared to controls (P=0.028, 0.007, and <0.0001, respectively). There were significantly more congenital anomalies (mainly limb deformities) among the IBD offspring (P<0.035). Offspring born post-maternal IBD diagnosis, compared to pre-diagnosis, tended to have more neurodevelopmental problems (e.g., gross motor delay, P=0.03). IBD was significantly more prevalent in the offspring of IBD mothers, while allergies and atopic dermatitis were more frequent in offspring of control mothers. More offspring of IBD mothers taking medications during pregnancy were born preterm and had lower birth weights compared to offspring of IBD mothers not taking medications during pregnancy. Children of mothers taking steroids had the lowest birth weights, compared to those of IBD mothers taking 5ASAs or immunomodulators. CONCLUSIONS: Maternal IBD affects pregnancy and the offspring's immediate and long-term morbidity, specifically, congenital anomalies and neurodevelopmental problems.

Long-term infliximab maintenance therapy for ulcerative colitis: the ACT-1 and -2 extension studies.

BACKGROUND: The aim was to evaluate long-term efficacy, quality of life, and safety in ulcerative colitis patients who received infliximab during the ACT-1 and -2 extension studies. METHODS: Adults with moderate-to-severely active ulcerative colitis in the 54-week ACT-1 and 30-week ACT-2 studies who achieved benefit from infliximab were eligible to participate in extension studies and receive up to 3 additional years of therapy. Patients received randomized study medication until all sites were unblinded; placebo-treated patients were discontinued. Patients receiving 5 or 10 mg/kg infliximab continued to receive open-label infliximab every 8 weeks. Patients receiving infliximab 10 mg/kg could decrease to 5 mg/kg; patients receiving infliximab 5 mg/kg could increase to 10 mg/kg if response was lost. RESULTS: A total of 229 of 484 infliximab-treated patients from the ACT-1 and ACT-2 main studies entered the long-term extensions. Overall, 70 (30.6%) patients discontinued infliximab infusions for adverse events (24 [10.5%]), lack of efficacy (11 [4.8%]), required a colectomy (1 [0.4%]), or for other reasons (34 [14.8%]). Proportions of patients whose Physician's Global Assessment scores were indicative of no or mild disease (score = 0 or 1) were maintained during the extension studies; 76.5% at Extension week 0 and ranged between 90.0% and 94.3% through Extension week 152. Improvement in Inflammatory Bowel Disease Questionnaire scores observed in the main studies was maintained. During the long-term extension, the infliximab safety profile was consistent with that of the main studies; no new or unexpected safety signals were observed. CONCLUSIONS: Long-term treatment with infliximab for up to 3 additional years was effective and well tolerated.

Relationship between CYP2A6 genetic polymorphism, as a marker of nicotine metabolism, and ulcerative colitis.

BACKGROUND: Ulcerative colitis (UC) is a common and difficult-to-treat disease. In non-smokers the relative risk of developing UC is 2.9 compared with smokers, who tend to have a later onset and a milder disease. Nicotine is the component of cigarette smoke responsible for the favorable effects in UC. Nicotine is metabolized by the enzyme CYP2A6. Subjects who are homozygotes for CYP2A6*4 gene polymorphism are poor nicotine metabolizers, while homozygotes for CYP2A6*1A polymorphism are extensive metabolizers. OBJECTIVES: To compare the frequency of CYP2A6 and CHRNA3 polymorphisms among smokers and non-smokers with UC, and their effect on disease severity. METHODS: Data on the age at onset of disease, disease activity, and treatment were obtained from questionnaires completed by the 69 subjects in our study group. CYP2A6 *1A,*4A and CHRNA3 polymorphisms were determined by polymerase chain reaction and restriction enzyme analysis. RESULTS: Nine percent of the patients were current smokers, 30% were former smokers and 61% non-smokers. Among smokers and former smokers 63% were homozygotes for CYP2A6*1A and 4% were homozygotes for CYP2A6*4A, whereas among non-smokers 66% were homozygotes for CYP2A6*4A (P < 0.0001). There was no significant effect of CYP2A6 or CHRNA3 genotype on UC activity. CONCLUSIONS: We found a very high proportion of poor nicotine metabolizers among non-smoking patients with UC and a very low proportion among current and former smokers, making it difficult to determine the effect of poor metabolizer genotype on disease activity in smokers with UC. However, it may be possible to identify UC patients who are poor metabolizers of nicotine and who may benefit from nicotine or nicotine-like pharmacological treatment.

A randomised placebo-controlled multicentre trial of intravenous semapimod HCl for moderate to severe Crohn's disease.

OBJECTIVE: Semapimod, a small molecule known to inhibit proinflammatory cytokine activity, was studied to determine the optimal dose necessary to achieve a response in patients with moderate to severe Crohn's disease (CD). METHODS: A randomised, double-blind, placebo-controlled trial (CD04) was carried out followed by an open-label extension study (CD05). The trial was conducted in international multicentre outpatient clinics and included patients with moderate to severe CD (Crohn's Disease Activity Index (CDAI) 250-400). Placebo was administered for 3 days; 60 mg semapimod intravenously for 1 day with placebo for 2 days; or 60 mg semapimod intravenously for 3 days. Participants who completed CD04 could participate in the open-label extension study, CD05, to receive up to five additional semapimod HCl 60 mg daily doses three times every 6-8 weeks. The main outcome measures were CDAI, Inflammatory Bowel Disease Questionnaire (IBDQ), Crohn's Disease Endoscopic Inflammation Score (CDEIS) and serum C-reactive protein (CRP) concentration. RESULTS: 152 patients were randomised in CD04. Responses for 1 and 3 day regimens were similar to placebo for CDAI (p=0.82), IBDQ (p=0.85), CDEIS (p=0.57) and CRP (p=0.40). The only noteworthy treatment-related safety finding was infusion reaction (phlebitis): 7.3, 34.8 and 62.7% for the placebo and 1 and 3 day semapimod treatment groups, respectively (p<0.001). In the open-label CD05 study (included=119 patients) a posthoc analysis showed that the mean CDAI improved in patients receiving 6 compared with < or = 3 cumulative doses (204.1+/-83 vs 251.4+/-103.05, p=0.006). CONCLUSIONS: Single and 3 day dosing of semapimod (< or = 180 mg) was ineffective for the treatment of moderate to severe CD. However, cumulative dosing > or = 360 mg was associated with decreased CDAI in a limited number of patients.

Infliximab, azathioprine, or combination therapy for Crohn's disease.

BACKGROUND: The comparative efficacy and safety of infliximab and azathioprine therapy alone or in combination for Crohn's disease are unknown. METHODS: In this randomized, double-blind trial, we evaluated the efficacy of infliximab monotherapy, azathioprine monotherapy, and the two drugs combined in 508 adults with moderate-to-severe Crohn's disease who had not undergone previous immunosuppressive or biologic therapy. Patients were randomly assigned to receive an intravenous infusion of 5 mg of infliximab per kilogram of body weight at weeks 0, 2, and 6 and then every 8 weeks plus daily oral placebo capsules; 2.5 mg of oral azathioprine per kilogram daily plus a placebo infusion on the standard schedule; or combination therapy with the two drugs. Patients received study medication through week 30 and could continue in a blinded study extension through week 50. RESULTS: Of the 169 patients receiving combination therapy, 96 (56.8%) were in corticosteroid-free clinical remission at week 26 (the primary end point), as compared with 75 of 169 patients (44.4%) receiving infliximab alone (P=0.02) and 51 of 170 patients (30.0%) receiving azathioprine alone (P<0.001 for the comparison with combination therapy and P=0.006 for the comparison with infliximab). Similar numerical trends were found at week 50. At week 26, mucosal healing had occurred in 47 of 107 patients (43.9%) receiving combination therapy, as compared with 28 of 93 patients (30.1%) receiving infliximab (P=0.06) and 18 of 109 patients (16.5%) receiving azathioprine (P<0.001 for the comparison with combination therapy and P=0.02 for the comparison with infliximab). Serious infections developed in 3.9% of patients in the combination-therapy group, 4.9% of those in the infliximab group, and 5.6% of those in the azathioprine group. CONCLUSIONS: Patients with moderate-to-severe Crohn's disease who were treated with infliximab plus azathioprine or infliximab monotherapy were more likely to have a corticosteroid-free clinical remission than those receiving azathioprine monotherapy. (ClinicalTrials.gov number, NCT00094458.)

Colectomy rate comparison after treatment of ulcerative colitis with placebo or infliximab.

BACKGROUND & AIMS: The efficacy of infliximab for treating patients with ulcerative colitis has been established. METHODS: The Active Ulcerative Colitis Trial (ACT)-1 and ACT-2 randomized, double-blind, placebo-controlled studies evaluated infliximab induction and maintenance therapy in moderately to severely active ulcerative colitis. Overall, 728 patients received placebo or infliximab (5 or 10 mg/kg) intravenously at weeks 0, 2, and 6, then every 8 weeks through week 46 (ACT-1) or 22 (ACT-2). Colectomy, hospitalization, and surgery/procedure data through 54 weeks after the first infusion were obtained from ACT-1, ACT-2, and associated data sources. In the prespecified analysis, all data were combined to ascertain time to colectomy. Kaplan-Meier product-limit method was used to estimate the cumulative incidence of colectomy, and log-rank test was used to compare the combined infliximab group and placebo. RESULTS: Eighty-seven percent (630 of 728) of patients had complete colectomy follow-up; 13% (98 of 728) of patients had a median follow-up of 6.2 months. The cumulative incidence of colectomy through 54 weeks was 10% for infliximab and 17% for placebo (P = .02), yielding an absolute risk reduction of 7%. Compared with placebo, fewer ulcerative colitis-related hospitalizations and surgeries/procedures per 100 patient-years of treatment occurred with infliximab therapy: 40 vs 20 (P = .003) and 34 vs 21 (P = .03), respectively. Serious adverse events occurring in infliximab-treated patients included serious infections, tuberculosis, histoplasmosis, listeriosis, and malignancy. CONCLUSIONS: Patients with moderately to severely active ulcerative colitis treated with infliximab were less likely to undergo colectomy through 54 weeks than those receiving placebo.

Dextran sodium sulfate-induced colitis causes rapid bone loss in mice.

INTRODUCTION: Osteopenia is a common complication of human inflammatory bowel disease (IBD). We evaluated the contribution of colonic inflammation to osteopenia and its mechanism in a murine colitis model. METHODS: Colitis was induced by adding dextran sodium sulfate (DSS) to the drinking water for 2 weeks to nine-week-old Balb/C male mice. 5% DSS was added on the first week and was reduced to 2.5% on the second week. Age- and sex-matched Balb/C mice served as the control group. Indices of femoral bone mass and architecture were determined by micro computed tomography (muCT). Bone formation parameters and osteoclast number were determined by dynamic histomorphometry. The degree of colonic inflammation was assessed by a clinical disease activity index, and colonic mucosal myeloperoxidase activity. RESULTS: DSS-treated mice exhibited a significantly lower bone mass compared to controls as indicated by decreased trabecular bone volume (BV/TV) of 32%. This reduction was accompanied by decreased trabecular number (23%) and connectivity density (37%) compared to the controls. No changes were observed in cortical bone indices. Osteopenia resulted from suppressed bone formation, as indicated by decreased trabecular double-labeled surface (dL%) of 90%, mineralizing surface (MS) of 62%, and bone formation rate (BFR) of 67%, and increased bone resorption as indicated by a 34% increase in osteoclast number in DSS-treated mice compared to the controls. Myeloperoxidase activity inversely correlated with trabecular BV/TV (r=-0.67, p=0.02), trabecular number (r=-0.86, p=0.0008) and connectivity density (r=-0.63, p=0.03). Myeloperoxidase activity inversely correlated with the bone formation indices: dL%, MS, and BFR (r=-0.79, p=0.007, r=-0.84, p=0.002, r=-0.83, p=0.003, respectively). CONCLUSIONS: DSS-induced colitis is associated with reduced femoral bone mass and altered micro architecture, which results from suppressed bone formation and increased bone resorption. The decrease in indices of bone mass, structure and formation are directly linked to the degree of colonic mucosal inflammation. DSS-induced colitis can be used to study pharmacological interventions for bone loss in colitis.

[Infliximab in inflammatory bowel diseases--conference summary and suggested guidelines].

Infliximab, the monoclonal anti-tumor necrosis factor-alpha (TNF-alpha) antibodies preparation, is efficacious in the treatment of inflammatory bowel diseases. However, the optimal therapeutic approach is still under investigation. Reports on side effects and potential complications of infliximab therapy, as well as of other anti-TNF-alpha blocking agents are accumulating. Hence, the Israeli Gastroenterological Association had initiated a conference in order to discuss the frequent clinical issues that have arisen following the use of infliximab for the treatment of inflammatory bowel diseases. The aim was to report on the published clinical experience and problems regarding several practical aspects of the use of Infliximab, to suggest guidelines that are evidence-based and to discuss them with experienced IBD-oriented gastroenterologists. The subjects that were discussed include: (1) treatment protocols; (2) maintenance therapy in Crohn's disease; (3) prevention of infections and (4) therapeutic potential in ulcerative colitis. These topics reflect everyday issues that gastroenterologists deal with while treating inflammatory bowel disease patients. The manuscript summarizes the literature and evidence that were presented in the conference, the points raised at the discussions as well as guidelines suggested by work groups that were established for each subject. These guidelines may assist and direct the gastroenterologist treating inflammatory bowel disease patients with infliximab.

Homeostatic effects of TLR9 signaling in experimental colitis.

The commensal microflora of the intestinal tract confer multiple health benefits to the host, including amelioration of inflammatory bowel disease (IBD). Yet, the exact mechanisms by which it ameliorates experimental colitis in animals and human IBD are largely unknown. We tested whether the attenuation of experimental colitis by probiotic bacteria is mediated by toll-like receptor (TLR) signaling. The severity of colitis was attenuated by delivery of nonviable, gamma-irradiated, or by viable probiotics, but not by heat-killed probiotics, in wild-type mice in mice deficient in TLR2 or TLR4. In contrast we did not observe any inhibition of experimental colitis by probiotics, in mice deficient in MyD88 or TLR9. Furthermore, administration of probiotic DNA ameliorated the severity of experimental colitis, whereas methylated probiotic DNA, calf thymus DNA, and Dnase-treated probiotics had no effect. In subsequent studies, we identified that TLR9-induced type 1 IFN mediates the anti-inflammatory effects in experimental colitis. The addition of neutralization antibodies to type 1 IFN abolished the anti-inflammatory effects, whereas the administration of recombinant IFN-beta mimicked the anti-inflammatory effects induced by TLR9 agonists. Taken together, these results indicate that the protective effects of probiotics are mainly mediated by their own DNA rather than by their metabolites or their ability to colonize the colon. These findings underscore the diverse effects of indigenous microbial TLR ligands in intestinal homeostasis and intestinal inflammation and suggest that strategies, that modulate type 1 IFN may be of therapeutic value for intestinal inflammatory conditions.

Onercept for moderate-to-severe Crohn's disease: a randomized, double-blind, placebo-controlled trial.

BACKGROUND AND AIMS: Onercept is a recombinant, soluble human p55 receptor to tumor necrosis factor-alpha. METHODS: A randomized, double-blind, placebo-controlled, dose-ranging trial was performed to evaluate the efficacy of onercept induction therapy in patients with Crohn's disease (CD). Patients (n = 207) with moderate-to-severe acute or chronic active CD were randomized to receive subcutaneous onercept (10, 25, 35, or 50 mg) or placebo 3 times weekly for 8 weeks. Primary analysis was induction of remission (defined as a CD activity index score < or = 150) at week 8. RESULTS: A total of 104 patients had acute active CD. Remission rates at week 8 were 23.5% for placebo (n = 17), and 34.8%, 20.0%, 26.1%, and 28.6% for onercept 10 mg (n = 23), 25 mg (n = 20), 35 mg (n = 23), and 50 mg (n = 21), respectively (P = .98). A total of 103 patients had chronic active CD. Remission rates at week 8 were 23.8% for placebo (n = 21), and 23.8%, 9.1%, 35.3%, and 13.6% for onercept 10 mg (n = 21), 25 mg (n = 22), 35 mg (n = 17), and 50 mg (n = 22), respectively (P = .66). There were no differences between treatment groups in the incidence of adverse events. However, mild-to-moderate injection-site reactions occurred in up to 12% of onercept-treated patients. CONCLUSIONS: Onercept was well tolerated but was not effective at the doses studied in patients with active CD.

Immunostimulatory oligonucleotides inhibit colonic proinflammatory cytokine production in ulcerative colitis.

BACKGROUND: We previously showed that Toll-like receptor-9 (TLR-9) ligands ameliorate experimental colitis. In this study, we evaluated the effect of TLR-9 ligands on the generation of proinflammatory cytokines by human colonic mucosa. MATERIALS AND METHODS: Colonoscopic biopsies were obtained from patients with active ulcerative colitis (UC) and from normal subjects. The tissue was organ cultured for 24 hours in the presence or absence of different types of immunostimulatory (ISS) (CpG)-oligonucleotides (ODNs). Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) levels in the medium were determined by enzyme-linked immunosorbent assay. RESULTS: In active UC, hTNF-alpha and hIL-lbeta generation by inflamed colonic mucosa is 7- and 3-fold higher, respectively, than their generation by normal mucosa. Class B CpG ODNs inhibited colonic TNF-alpha and IL-1beta generation by 50%, whereas class A or C ODNs had a partial or no effect, respectively. A novel class of ODNs that is based on multiple TCG repeats was as effective as class B ODNs. This inhibition resulted from the transcriptional suppression of IL-1beta that occurred within the first 2 hours after ISS-ODN incubation. The addition of chloroquine abolished the inhibitory effects of ISS-ODNs on colonic TNF-alpha and IL-1beta generation. CONCLUSIONS: Only certain classes of ISS-ODNs inhibit the enhanced TNF-alpha and IL-1beta generated ex vivo by inflamed colonic mucosa of patients with UC. The effect of ISS-ODNs is mediated by triggering of TLR-9. These results suggest a potential therapeutic value for ISS-ODNs in UC.

Infliximab for induction and maintenance therapy for ulcerative colitis.

BACKGROUND: Infliximab, a chimeric monoclonal antibody directed against tumor necrosis factor alpha, is an established treatment for Crohn's disease but not ulcerative colitis. METHODS: Two randomized, double-blind, placebo-controlled studies--the Active Ulcerative Colitis Trials 1 and 2 (ACT 1 and ACT 2, respectively)--evaluated the efficacy of infliximab for induction and maintenance therapy in adults with ulcerative colitis. In each study, 364 patients with moderate-to-severe active ulcerative colitis despite treatment with concurrent medications received placebo or infliximab (5 mg or 10 mg per kilogram of body weight) intravenously at weeks 0, 2, and 6 and then every eight weeks through week 46 (in ACT 1) or week 22 (in ACT 2). Patients were followed for 54 weeks in ACT 1 and 30 weeks in ACT 2. RESULTS: In ACT 1, 69 percent of patients who received 5 mg of infliximab and 61 percent of those who received 10 mg had a clinical response at week 8, as compared with 37 percent of those who received placebo (P<0.001 for both comparisons with placebo). A response was defined as a decrease in the Mayo score of at least 3 points and at least 30 percent, with an accompanying decrease in the subscore for rectal bleeding of at least 1 point or an absolute rectal-bleeding subscore of 0 or 1. In ACT 2, 64 percent of patients who received 5 mg of infliximab and 69 percent of those who received 10 mg had a clinical response at week 8, as compared with 29 percent of those who received placebo (P<0.001 for both comparisons with placebo). In both studies, patients who received infliximab were more likely to have a clinical response at week 30 (P< or =0.002 for all comparisons). In ACT 1, more patients who received 5 mg or 10 mg of infliximab had a clinical response at week 54 (45 percent and 44 percent, respectively) than did those who received placebo (20 percent, P<0.001 for both comparisons). CONCLUSIONS: Patients with moderate-to-severe active ulcerative colitis treated with infliximab at weeks 0, 2, and 6 and every eight weeks thereafter were more likely to have a clinical response at weeks 8, 30, and 54 than were those receiving placebo. (ClinicalTrials.gov numbers, NCT00036439 and NCT00096655.)

Increased severity of experimental colitis in alpha 5 nicotinic acetylcholine receptor subunit-deficient mice.

Substantial evidence suggests a negative association between cigarette smoking and the incidence and severity of ulcerative colitis, a common human inflammatory bowel disease. Nicotine has been implicated in this association. The detection of nicotinic acetylcholine receptors in colonic epithelium, the primary tissue affected in ulcerative colitis, suggests a role for these receptors in the beneficial effect of nicotine on colonic inflammation. Using an animal model, we demonstrate for the first time that alpha5 nicotinic acetylcholine receptor knockout mice have significantly more severe experimental colitis than wild-type controls and that nicotine significantly ameliorates its course when compared with wild-type controls. These findings suggest that alpha5-containing nicotinic acetylcholine receptors participate in the modulation of colitis in mice, but other nicotinic acetylcholine receptor subunits also mediate the antiinflammatory effects of nicotine.

Probiotics in inflammatory bowel disease: possible mechanisms of action.

PURPOSE OF REVIEW: Probiotics are live, nonpathogenic bacteria that confer health benefits beyond their nutritional value. In inflammatory bowel disease, where changes in bacterial flora have been demonstrated, there is an increasing interest in modulating the flora with probiotic strains. The beneficial effect of probiotics is demonstrated mainly in pouchitis and ulcerative colitis; however, their mechanisms of action are not well defined. The purpose of this review is to discuss the latest findings related to their mechanism of action. RECENT FINDINGS: A decrease in the secretion of pro-inflammatory cytokines, IFN-gamma, TNF-alpha and IL-12, and interference with bacterial adherence to the epithelium has been demonstrated. At the molecular level, an anti-inflammatory effect associated with NF-kappaB inhibition, heat-shock protein induction and proteasome inhibition has been suggested, although NF-kappaB induction has also been demonstrated. Unexpectedly, the beneficial effects described were achieved not only by live bacteria but also by gamma-irradiated nonviable bacteria, bacterial DNA components and probiotic-cultured media. SUMMARY: Understanding the mechanisms responsible for the beneficial effect of probiotics in inflammatory bowel disease and experimental colitis may help understand the role of bacteria in disease pathogenesis. The findings that live probiotics may not be mandatory to be beneficial, and that therapeutic effects may be obtained by systemic, rather than oral administration could have a major impact on the practical use and manufacturing of probiotics.

Toll-like receptor 9-induced type I IFN protects mice from experimental colitis.

Experimental colitis is mediated by inflammatory or dysregulated immune responses to microbial factors of the gastrointestinal tract. In this study we observed that administration of Toll-like receptor 9 (TLR9) agonists suppressed the severity of experimental colitis in RAG1-/- but not in SCID mice. This differential responsiveness between phenotypically similar but genetically distinct animals was related to a partial blockade in TLR9 signaling and defective production of type I IFN (i.e., IFN-alpha/beta) in SCID mice upon TLR9 stimulation. The addition of neutralization antibodies against type I IFN abolished the antiinflammatory effects induced by TLR9 agonists, whereas the administration of recombinant IFN-beta mimicked the antiinflammatory effects induced by TLR9 agonists in this model. Furthermore, mice deficient in the IFN-alpha/beta receptor exhibited more severe colitis than wild-type mice did upon induction of experimental colitis. These results indicate that TLR9-triggered type I IFN has antiinflammatory functions in colitis. They also underscore the important protective role of type I IFN in intestinal homeostasis and suggest that strategies to modulate innate immunity may be of therapeutic value for the treatment of intestinal inflammatory conditions.

Interleukin 10-deficient mice develop osteopenia, decreased bone formation, and mechanical fragility of long bones.

BACKGROUND & AIMS: Bone loss is a common complication of human inflammatory bowel disease (IBD), but its mechanisms are not understood completely. We investigated bone metabolism in interleukin-10-deficient ( IL-10-/- ) mice, an animal model with IBD features. METHODS: IL-10-/- male mice (8- and 12-weeks-old) and their age-matched wild-type counterparts (C57BL/6J) were studied. Bone mass of the femur was determined by ashing. Tibial cancellous and cortical bone mass and formation was measured by static and dynamic histomorphometry. Biomechanical strength of the femur was tested. Primary bone marrow stromal cell cultures were used to assess osteoblast generation. Serum levels of 25-OH vitamin D 3, insulin-like growth factor-1 (IGF-1), parathyroid hormone, osteocalcin, and deoxy-pyridinoline cross-links were measured. The presence of colitis was determined histologically, and by IL-12 and interferon-gamma (IFN-gamma) secretion from cultured colonic explants. RESULTS: Eight- and 12-week-old IL-10-/- mice developed osteopenia of both cancellous and cortical bone, evidenced by lower femoral ash weight, cancellous bone area and surface, trabecular number, and decreased cortical bone area and width. Osteopenia was associated with mechanical fragility, manifested by decreased stiffness and mechanical load at fracture, and was caused by suppressed bone formation, indicated by decreased cancellous double-labeled surface, mineralizing surface, serum osteocalcin level, and mineralized nodule number in bone marrow stromal cell cultures. IL-10-/- mice with colitis had significantly less bone mass compared with IL-10-/- mice without colitis. CONCLUSIONS: IL-10-/- mice develop the hallmarks of osteoporosis, that is, reduced bone mass, increased mechanical fragility, and suppressed bone formation. The presence of colitis is an important contributor to osteoporosis in IL-10-/- mice.