Tom G. Moreels

Second European evidence-based consensus on the prevention, diagnosis and management of opportunistic infections in inflammatory bowel disease

The treatment of inflammatory bowel disease (IBD) has been revolutionised over the past decade by the increasing use of immunomodulators, mainly azathioprine (AZA)/6-mercaptopurine (6-MP) and methotrexate (MTX), together with the advent of biological therapy. Immunomodulators are being used more often and earlier in the course of the disease.1 The introduction of biologic agents, especially inhibitors of the key proinflammatory cytokine, tumor necrosis factor alpha (TNF-α) initiated a new therapeutic era, whose use has grown continuously since their introduction in 1998.2 With such immunomodulation, the potential for opportunistic infection is a key safety concern for patients with IBD. Opportunistic infections pose particular problems for the clinician: they are often difficult to recognise and are associated with appreciable morbidity or mortality, because they are potentially serious and hard to treat effectively. Enhancing awareness and improving the knowledge of gastroenterologists about opportunistic infections are important elements to optimise patient outcomes through the development of preventive or early diagnostic strategies. A long list of opportunistic infections has been described in patients with IBD. Many questions remain unanswered, not only concerning the need for screening, preventive measures or the best diagnostic approach, but also on appropriate treatment and management of immunomodulator therapy once infection occurs. This led the European Crohns and Colitis Organisation (ECCO) to establish a Consensus meeting on opportunistic infections in IBD. The formal process of a Consensus meeting has been described,3 but the purpose is to quantify expert opinion in the context of a systematic review of existing evidence. To organise the work, infections were classified into six major topics (see plan). Specific questions were asked for each infectious agent. The different topics were distributed to working groups that comprised junior and senior gastroenterologists with infectious disease experts. Each group performed a systematic review of the literature and answered …

Effect of adrenergic and nitrergic blockade on experimental ileus in rats

1 In a rat model of experimental ileus, the effect of blockade of adrenergic and nitrergic neurotransmission was studied on the intestinal transit of Evans blue. 2 Ether anaesthesia and skin incision had no influence on the transit. Laparotomy significantly inhibited the transit of Evans blue. This inhibition was even more pronounced when the small intestine was manipulated. 3 Reserpine (5 mg kg−1), a drug that blocks adrenergic neurotransmission, completely reversed the inhibition of the transit induced by laparotomy but only partially reversed that induced by laparotomy with manipulation of the small intestine. 4 Nω‐nitro‐L‐arginine (L‐NOARG, 5 mg kg−1), a nitric oxide synthase inhibitor, completely reversed the reserpine‐resistant inhibition induced by laparotomy with manipulation of the small intestine. The effect of L‐NOARG was prevented by concomitant administration of L‐arginine. L‐Arginine itself slightly, but significantly enhanced the inhibition. S‐methylisothiourea and aminoguanidine, selective inhibitors of the inducible NO synthase, had no effect on the transit after the three operations. 5 Treatment of the rats with reserpine plus L‐NOARG had no additional effect on the transit after laparotomy as compared to reserpine alone. However, reserpine plus L‐NNA completely reversed the inhibition of the transit induced by laparotomy with manipulation of the small intestine. 6 These findings support the involvement of adrenergic pathways in the pathogenesis of ileus and suggest that the additional inhibitory effect of mechanical stimulation results from an enhanced release of NO by the constitutive NO synthase.

Concurrent infection with Schistosoma mansoni attenuates inflammation induced changes in colonic morphology, cytokine levels, and smooth muscle contractility of trinitrobenzene sulphonic acid induced colitis in rats

Background and aims: Crohn’s disease, characterised by chronic T helper 1 (Th1) inflammation and dysmotility of the gut, is most prevalent in developed countries. Parasitic infections are most prevalent in developing countries and induce a T helper 2 (Th2) immune response. We hypothesised that this Th2 immune response protects against Th1 gut inflammation. Methods: The parasite Schistosoma mansoni induces a transient Th2 immune response in the semipermissive rat host. 2,4,6-Trinitrobenzene sulphonic acid (TNBS) induced colitis is an experimental model of Th1-like gut inflammation. The effect of concurrent infection with S mansoni on the course of TNBS induced colitis was assessed using macroscopic and microscopic damage scores, histology, myeloperoxidase (MPO) activity assay, cytokine production assay, and by studying in vitro contractility of longitudinal and circular colonic muscle strips. Results: TNBS induced colitis that spontaneously healed after four weeks. Concurrent infection with S mansoni significantly reduced the duration of TNBS induced colitis to two weeks, as shown by macroscopic and microscopic damage scores and by a faster decrease in colonic MPO activity. TNBS increased colonic interleukin 2 (IL-2) production whereas S mansoni increased splenic IL-4 and IL-2 levels. Contractility of longitudinal and circular muscle strips was maximally inhibited one week after TNBS and normalised after three weeks. After four weeks, longitudinal muscle strip contractility was significantly increased. Concurrent infection with S mansoni normalised longitudinal muscle contractility after one week whereas circular muscle contractility remained inhibited. Conclusions: Concurrent infection with S mansoni significantly attenuates TNBS induced colitis in the rat. Inflammation induced disturbances in contractility of longitudinal and circular colonic muscle strips may outlast the inflammatory reaction.

Endoscopic improvement of mucosal lesions in patients with moderate to severe ileocolonic Crohn's disease following treatment with certolizumab pegol

Objective To evaluate the efficacy of certolizumab pegol (CZP) in improving endoscopic lesions in patients with active ileocolonic Crohns disease (CD). Methods This phase IIIB multicentre open-label clinical trial enrolled 89 adult patients with active endoscopic disease (ulceration in ≥2 intestinal segments with a Crohns Disease Endoscopic Index of Severity (CDEIS) score ≥8 points). Patients received subcutaneous CZP 400 mg at weeks 0, 2 and 4 and every 4 weeks up to week 52. Endoscopic evaluations were performed at weeks 0, 10 and 54. The primary outcome was mean change in CDEIS score at week 10; secondary outcome measures included endoscopic response (decrease in CDEIS score >5 points), remission (CDEIS score <6), complete remission (CDEIS score <3) and mucosal healing (no ulcer) at weeks 10 and 54. Results In the intention-to-treat population (n=89) the mean±SD CDEIS score was 14.5±5.3 at baseline; the mean decrease in CDEIS score at week 10 was 5.7 (95% CI 4.6 to 6.8, p<0.0001). Rates of endoscopic response, endoscopic remission, complete endoscopic remission and mucosal healing at week 10 were 54%, 37%, 10% and 4%, respectively. At week 54 the corresponding rates were 49%, 27%, 14% and 8%, respectively. The safety profile was consistent with that of previous CZP trials. Conclusions Following CZP treatment in patients with active CD, endoscopic lesions were improved as shown by the decrease in mean CDEIS score and by endoscopic response and remission rates. These benefits were achieved as early as week 10 and were generally maintained through week 54. Clinical Trial Registration Number NCT00297648.

Therapeutic potential of helminth soluble proteins in TNBS‐induced colitis in mice

Background: The hygiene hypothesis suggests an inverse relationship between the incidence of parasitic infections and chronic inflammatory bowel diseases (IBD). We investigated the therapeutic potential of Schistosoma mansoni and Ancylostoma caninum soluble proteins on experimental colitis in mice. Methods: Colitis was induced by intrarectal administration of 10 mg trinitrobenzene sulfonic acid (TNBS) in 30% ethanol. Six hours after TNBS injection, mice were treated intraperitoneally with helminth proteins. Three days later, colonic inflammation was scored based on 5 inflammatory parameters: clinical disease activity, macroscopic and microscopic inflammation score, extent of inflammation, and myeloperoxidase (MPO) activity. To determine immunological pathways induced by S. mansoni proteins we measured cytokine profiles of T‐lymphocytes from colon, mesenteric lymph nodes (MLN), and spleen by real‐time reverse‐transcriptase polymerase chain reaction (RT‐PCR). Results: Control mice showed no signs of inflammation, whereas all inflammatory parameters were significantly increased in mice with colitis. Treatment of mice with colitis with S. mansoni or A. caninum proteins decreased the macroscopic inflammation score, extent of inflammation, and MPO activity. Immunologically, induction of colitis significantly increased expression of IFN‐γ mRNA in the inflamed colon. Treatment with S. mansoni proteins caused a decrease of proinflammatory cytokines (IFN‐γ, IL‐17) in colon and MLN, whereas the production of regulatory cytokines (IL‐10, TGF‐β) increased significantly in colon tissue. Conclusions: Treatment with proteins of S. mansoni and A. caninum ameliorated TNBS‐induced colitis in mice. S. mansoni proteins increased mRNA expression of regulatory cytokines while suppressing expression of proinflammatory cytokines. Therefore, we suggest a therapeutic potential for helminth proteins in the treatment of IBD. (Inflamm Bowel Dis 2009)

Consecutive fecal calprotectin measurements to predict relapse in patients with ulcerative colitis receiving infliximab maintenance therapy

Background: This study examined whether fecal calprotectin can be used in daily practice as a marker to monitor patients with ulcerative colitis (UC) receiving infliximab maintenance therapy. Methods: This prospective multicenter study enrolled adult patients with UC in clinical remission under infliximab maintenance therapy. Fecal calprotectin levels were measured every 4 weeks. Sigmoidoscopies were performed at inclusion and at study end. Relapse was defined as a clinical need for change in treatment or an endoscopic Mayo subscore of ≥2 at week 52. Sustained deep remission was defined as a partial Mayo score <3 at all points and an endoscopic Mayo score 0 at week 52. Results: Full analysis was possible for 87 of 113 included patients with UC (77%). Of these patients, 30 (34.4%) were considered to be in sustained deep remission and 13 (14.9%) to have relapsed. Calprotectin levels in patients with sustained deep remission remained very low (median < 40 mg/kg at all time points). Patients who flared had significantly higher calprotectin levels (median > 300 mg/kg) already 3 months before the flare. Further receiver operator curve analysis suggested that a calprotectin level >300 mg/kg had a reasonable sensitivity (58.3%) and specificity (93.3%) to model flare. Two consecutive calprotectin measurements of >300 mg/kg with 1-month interval were identified as the best predictor of flare (61.5% sensitivity and 100% specificity). Conclusions: Fecal calprotectin can be used in daily practice to monitor patients with UC receiving infliximab maintenance therapy. Two consecutive measurements >300 mg/kg is more specific than a single measurement for predicting relapse.

Fast and sharp decrease in calprotectin predicts remission by infliximab in anti-TNF naïve patients with ulcerative colitis.

AIM To evaluate the effect of infliximab induction therapy on calprotectin levels in patients with ulcerative colitis (UC). PATIENTS AND METHODS In this prospective study 53 patients with active UC from 17 centers were treated with infliximab therapy (5 mg/kg) at baseline, week 2, and week 6. Faecal calprotectin was measured every week. Sigmoidoscopies were performed at baseline, week 6 and week 10. RESULTS Median calprotectin levels decreased from 1260 (IQR 278.5- 3418) at baseline to 72.5 (IQR 18.5 - 463) at week 10 (p<0.001). After 10 weeks, infliximab therapy induced endoscopic remission and a decrease in calprotectin to<50 mg/kg or at least a 80% decrease from baseline level in 58% of patients. A significant and steep decrease of calprotectin levels was seen at week 2 for patients with an endoscopic remission at week 10 as compared to patients who did not show a remission. (p<0.001). At week 10 an excellent correlation was found between endoscopic remission and clinical Mayo score reflected by an AUC of ROC analyses of 0.94 (0.87-1) and with calprotectin measurements (AUC 0.91 (0.81-1)) : all patients with calprotectin levels <50 mg/kg, and a normal clinical Mayo score (=0) were in endoscopic remission. CONCLUSIONS Infliximab induces a fast and significant decrease of faecal calprotectin levels in anti-TNF naïve patients with ulcerative colitis predictive for remission of disease.

Effect of inhibition of inducible nitric oxide synthase and guanylyl cyclase on endotoxin-induced delay in gastric emptying and intestinal transit in mice

Nitric oxide (NO) is postulated to play a role in endotoxin-induced ileus. We investigated the effect of selective blockade of inducible NO synthase (iNOS) and guanylyl cyclase on endotoxin-induced ileus in mice. Thirty minutes before injection of lipopolysaccharides (LPS), mice were pretreated with L-NAME (Nω-nitro-L-arginine methyl ester, non-selective NOS inhibitor), 1400W (N-(3-(aminomethyl)benzyl)acetamide, selective iNOS inhibitor), ODQ (1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one, guanylyl cyclase inhibitor), dimethyl sulfoxide (DMSO, vehicle), or dexamethasone. After 18 h, general well being deteriorated and the mice developed hypothermia and a significant delay in gastric emptying and intestinal transit as measured by Evans blue. 1400W completely reversed the endotoxin-induced delay in gastric emptying, while L-NAME did not have these beneficial effects. On the contrary, even in control mice, L-NAME delayed gastric emptying. Dexamethasone, DMSO, and ODQ mimicked the effect of 1400W on endotoxin-induced delay in gastric emptying. The endotoxin-induced delay in transit was significantly improved only by 1400W. None of the drugs reversed the hypothermia. In LPS mice treated with L-NAME, the behavior scale increased even further, while it decreased after treatment with 1400W. In conclusion, selective inhibition of iNOS reverses the endotoxin-induced delay in gastric emptying and transit and improves general well being. The pathway used by NO, derived from iNOS, may involve inhibition of guanylyl cyclase or radical scavenging.

Effect of different prokinetic agents and a novel enterokinetic agent on postoperative ileus in rats

BACKGROUND/AIM The effects of different prokinetic agents, the motilide erythromycin and the substituted benzamides metoclopramide and cisapride, were investigated in a rat model of postoperative ileus. These effects were compared with that of granisetron, a 5-hydroxytryptamine (5-HT3) receptor antagonist, and a novel enterokinetic agent, prucalopride, a 5-HT4 receptor agonist. METHODS Different degrees of inhibition of gastrointestinal transit, measured by the migration of Evans blue, were achieved by skin incision, laparotomy, or laparotomy plus mechanical stimulation of the gut. RESULTS Metoclopramide decreased the transit after laparotomy with or without mechanical stimulation, whereas cisapride increased it after all three operations. Granisetron had no effect on the transit after the three operations when given alone. Prucalopride tended to increase the transit after laparotomy with or without mechanical stimulation when given alone. However, statistical significance was only reached when prucalopride was combined with granisetron. Erythromycin, a motilin receptor agonist, did not improve postoperative ileus in the rat. CONCLUSIONS Cisapride, but not metoclopramide or erythromycin, is able to improve postoperative ileus in the rat. The results suggest that a combination of 5-HT3 receptor antagonist and 5-HT4 receptor agonist properties may be required to obtain a beneficial effect on surgery induced ileus in the rat. Furthermore, they indirectly indicate that stimulation of the excitatory mechanisms is not able to overcome the inhibitory influence of the neural reflex pathways activated during abdominal surgery.

Schistosoma mansoni infection causing diffuse enteric inflammation and damage of the enteric nervous system in the mouse small intestine.

Schistosomiasis mansoni is a major health problem, mainly occurring in developing countries. A large proportion of infected individuals suffers from motility‐related gastrointestinal problems. In the present study, the diffuse inflammatory response in the small bowel wall, as compared to the egg‐induced granulomatous inflammation, was investigated. For this purpose, OF1 mice infected with Schistosoma mansoni 8–16 weeks prior to the experiment, and uninfected control mice were studied. The ileum showed both a diffuse mucosal inflammation as well as a granulomatous reaction. The diffuse mucosal inflammation caused an increase in the thickness of the mucosa, with blunting of the villi. A significant, transient increase of thickness of the muscularis propria after 12 weeks of infection was noted. There was an infection‐related mast cell infiltrate in the muscularis propria, consisting of formalin fixation‐insensitive connective tissue mast cells. Ganglionitis of the myenteric plexus was noted. Rarely, ganglia of the myenteric plexus contained apoptotic cells. A general pharmacological set of experiments showed a significant increase in intestinal contractility, both to exogenously administered, as well as to endogenously released neurotransmitters. Our results demonstrate that S. mansoni infection in the mouse ileum leads to diffuse specific enteric inflammation that is associated with an enhanced response to contractile agents.