Levinus A. Dieleman

Chronic experimental colitis induced by dextran sulphate sodium (DSS) is characterized by Th1 and Th2 cytokines

Oral administration of DSS has been reported to induce an acute and chronic colitis in mice. The aim of our study was to evaluate if the chronic phase of DSS‐induced colitis was characterized by a Th1/Th2 response and how this would relate to mucosal regeneration. Swiss Webster mice were fed 5% DSS in their drinking water for 7 days, followed by 2–5 weeks consumption of water. Control mice received only water. The animals were killed at 3 and 6 weeks after induction. Their colons were isolated for histology and immunohistochemistry, using specific MoAbs for T and B cells, macrophages, interferon‐gamma (IFN‐γ), IL‐4 and IL‐5. Colons were scored for inflammation, damage and regeneration. Two weeks after stopping DSS the colonic epithelium had only partially healed. Total colitis scores were still increased, especially in the distal colon, which was due to more inflammation, damage and less regeneration. In areas of incomplete colonic healing the basal parts of the lamina propria contained macrophages and CD4+ T cells. These CD4+ T cells showed a focal increase of IFN‐γ and IL‐4 staining compared with control animals. These findings were still observed 5 weeks after stopping DSS in some mice, albeit less extensive. Chronic DSS‐induced colitis is characterized by focal epithelial regeneration and a Th1 as well as Th2 cytokine profile. We postulate that chronic immune activation mediated by both populations of Th cells can interfere with colonic healing and can play a role in the pathogenesis of chronic colitis.

Lactobacillus plantarum 299V in the treatment and prevention of spontaneous colitis in interleukin-10-deficient mice.

Interleukin (IL)-10-deficient (IL-10−/−) mice develop colitis under specific pathogen-free (SPF) conditions and remain disease free if kept sterile (germ free [GF]). We used four different protocols that varied the time-points of oral administration of Lactobacillus plantarum 299v (L. plantarum) relative to colonization with SPF bacteria to determine whether L. plantarum could prevent and treat colitis induced by SPF bacteria in IL-10−/− mice and evaluated the effect of this probiotic organism on mucosal immune activation. Assessment of colitis included blinded histologic scores, measurements of secreted colonic immunoglobulin isotypes, IL-12 (p40 subunit), and interferon (IFN)-&ggr; production by anti-CD3-stimulated mesenteric lymph node cells. Treating SPF IL-10−/− mice with L. plantarum attenuated previously established colonic inflammation as manifested by decreased mucosal IL-12, IFN-&ggr;, and immunoglobulin G2a levels. Colonizing GF animals with L. plantarum and SPF flora simultaneously had no protective effects. Gnotobiotic IL-10−/− mice monoassociated with L. plantarum exhibited mild immune system activation but no colitis. Pretreatment of GF mice by colonization with L. plantarum, then exposure to SPF flora and continued probiotic therapy significantly decreased histologic colitis scores. These results demonstrate that L. plantarum can attenuate immune-mediated colitis and suggest a potential therapeutic role for this agent in clinical inflammatory bowel diseases.

Different Subsets of Enteric Bacteria Induce and Perpetuate Experimental Colitis in Rats and Mice

ABSTRACT Resident bacteria are incriminated in the pathogenesis of experimental colitis and inflammatory bowel diseases. We investigated the relative roles of various enteric bacteria populations in the induction and perpetuation of experimental colitis. HLA-B27 transgenic rats received antibiotics (ciprofloxacin, metronidazole, or vancomycin-imipenem) in drinking water or water alone in either prevention or treatment protocols. Mice were treated similarly with metronidazole or vancomycin-imipenem before or after receiving 5% dextran sodium sulfate (DSS). Germfree transgenic rats were colonized with specific-pathogen-free enteric bacteria grown overnight either in anaerobic or aerobic atmospheres. Nontransgenic rats colonized with anaerobic bacteria served as negative controls. Although preventive metronidazole significantly attenuated colitis in transgenic rats and DSS-treated mice, it had no therapeutic benefit once colitis was established. Ciprofloxacin also partially prevented but did not treat colitis in B27 transgenic rats. In both animal models vancomycin-imipenem most effectively prevented and treated colitis. Germfree transgenic rats reconstituted with enteric bacteria grown under anaerobic conditions had more aggressive colitis than those associated with aerobic bacteria. These results suggest that a subset of resident luminal bacteria induces colitis, but that a complex interaction of commensal aerobic and anaerobic bacteria provides the constant antigenic drive for chronic immune-mediated colonic inflammation.

Impaired mucosal defense to acute colonic injury in mice lacking cyclooxygenase-1 or cyclooxygenase-2

To investigate roles in intestinal inflammation for the 2 cyclooxygenase (COX) isoforms, we determined susceptibility to spontaneous and induced acute colitis in mice lacking either the COX-1 or COX-2 isoform. We treated wild-type, COX-1(-/-), COX-2(-/-), and heterozygous mice with dextran sodium sulfate (DSS) to provoke acute colonic inflammation, and we quantified tissue damage, prostaglandin (PG) E(2), and interleukin-1beta. No spontaneous gastrointestinal inflammation was detected in mice homozygous for either mutation, despite almost undetectable basal intestinal PGE(2) production in COX-1(-/-) mice. Both COX-1(-/-) and COX-2(-/-) mice showed increased susceptibility to a low-dose of DSS that caused mild colonic epithelial injury in wild-type mice. COX-2(-/-) mice were more susceptible than COX-1(-/-) mice, and selective pharmacologic blockade of COX-2 potentiated injury in COX-1(-/-) mice. At a high dose, DSS treatment was fatal to 50% of the animals in each mutant group, but all wild-type mice survived. DSS treatment increased PGE(2) intestinal secretion in all groups except COX-2(-/-) mice. These results demonstrate that COX-1 and COX-2 share a crucial role in the defense of the intestinal mucosa (with inducible COX-2 being perhaps more active during inflammation) and that neither isoform is essential in maintaining mucosal homeostasis in the absence of injurious stimuli.

Ustekinumab as Induction and Maintenance Therapy for Crohn’s Disease

BACKGROUND Ustekinumab, a monoclonal antibody to the p40 subunit of interleukin-12 and interleukin-23, was evaluated as an intravenous induction therapy in two populations with moderately to severely active Crohns disease. Ustekinumab was also evaluated as subcutaneous maintenance therapy. METHODS We randomly assigned patients to receive a single intravenous dose of ustekinumab (either 130 mg or approximately 6 mg per kilogram of body weight) or placebo in two induction trials. The UNITI-1 trial included 741 patients who met the criteria for primary or secondary nonresponse to tumor necrosis factor (TNF) antagonists or had unacceptable side effects. The UNITI-2 trial included 628 patients in whom conventional therapy failed or unacceptable side effects occurred. Patients who completed these induction trials then participated in IM-UNITI, in which the 397 patients who had a response to ustekinumab were randomly assigned to receive subcutaneous maintenance injections of 90 mg of ustekinumab (either every 8 weeks or every 12 weeks) or placebo. The primary end point for the induction trials was a clinical response at week 6 (defined as a decrease from baseline in the Crohns Disease Activity Index [CDAI] score of ≥100 points or a CDAI score <150). The primary end point for the maintenance trial was remission at week 44 (CDAI score <150). RESULTS The rates of response at week 6 among patients receiving intravenous ustekinumab at a dose of either 130 mg or approximately 6 mg per kilogram were significantly higher than the rates among patients receiving placebo (in UNITI-1, 34.3%, 33.7%, and 21.5%, respectively, with P≤0.003 for both comparisons with placebo; in UNITI-2, 51.7%, 55.5%, and 28.7%, respectively, with P<0.001 for both doses). In the groups receiving maintenance doses of ustekinumab every 8 weeks or every 12 weeks, 53.1% and 48.8%, respectively, were in remission at week 44, as compared with 35.9% of those receiving placebo (P=0.005 and P=0.04, respectively). Within each trial, adverse-event rates were similar among treatment groups. CONCLUSIONS Among patients with moderately to severely active Crohns disease, those receiving intravenous ustekinumab had a significantly higher rate of response than did those receiving placebo. Subcutaneous ustekinumab maintained remission in patients who had a clinical response to induction therapy. (Funded by Janssen Research and Development; ClinicalTrials.gov numbers, NCT01369329 , NCT01369342 , and NCT01369355 .).

Lactobacillus GG prevents recurrence of colitis in HLA-B27 transgenic rats after antibiotic treatment

Background and aims:Bacteroides vulgatus induces colitis in gnotobiotic HLA-B27 transgenic (TG) rats while broad spectrum antibiotics prevent and treat colitis in specific pathogen free (SPF) TG rats although disease recurs after treatment ends. Lactobacilli treat human pouchitis and experimental colitis. We investigated if Lactobacillus rhamnosus GG (L GG) can prevent colitis in TG rats monoassociated with B vulgatus and if L GG or Lactobacillus plantarum 299v (LP 299v) can treat established colitis in SPF TG rats and prevent recurrent disease after antibiotics were stopped. Methods: Germfree B27 TG rats were monoassociated with B vulgatus for four weeks following two weeks of colonisation with L GG or no bacteria. SPF B27 TG rats received oral vancomycin and imipenem for two weeks, or water alone, followed by four weeks of treatment with oral L GG, LP 299v, or water only. Disease activity was quantified by blinded gross and histological scores, caecal myeloperoxidase (MPO) activity, and levels of interleukin (IL)-1β, tumour necrosis factor (TNF), transforming growth factor β, and IL-10. Results:L GG did not prevent colitis in B vulgatus co-associated TG rats or treat established disease in SPF rats. However, L GG but not LP 299v prevented colitis relapse in antibiotic treated rats with reduced gross and histological scores, caecal MPO, IL-1β, and TNF whereas caecal IL-10 was increased. Conclusions:L GG does not prevent colitis in gnotobiotic TG rats or treat established disease in SPF rats, but is superior to LP 299v in the prevention of recurrent colitis. These studies suggest that antibiotics and probiotic agents provide synergistic therapeutic effects, perhaps mediated by altered immunomodulation with selective activity of different lactobacillus species.

Recommendations for Probiotic Use—2011 Update

This study describes the consensus opinion of the participants of the third Yale Workshop on probiotic use. There were 10 experts participating. The recommendations update those of the first 2 meetings that were published in 2005 and 2008. The workshop presentations and papers in this supplement relate to the involvement of normal microbiota involved in intestinal microecology, how the microbes interact with the intestine to affect our immunologic responses, the stability and natural history of probiotic organisms, and the role of the intestinal microbatome with regard to affecting cardiac risk factors and obesity. Recommendations for the use of probiotics in necrotizing enterocolitis, childhood diarrhea, inflammatory bowel disease, irritable bowel syndrome, and Clostridium difficile diarrhea are reviewed. As in previous publications, the recommendations are given as A, B, or C ratings. The recent positive experiences with bacteriotherapy (fecal microbiome transplant) are also discussed in detail and a positive recommendation is made for use in severe resistant C. difficile diarrhea.

Reduction of colitis by prebiotics in HLA-B27 transgenic rats is associated with microflora changes and immunomodulation.

&NA; HLA‐B27 transgenic rats develop spontaneous colitis under specific pathogen‐free conditions (SPF) but germ‐free rats remain disease‐free, emphasizing a role for intestinal bacteria in the pathogenesis of chronic intestinal inflammation. Prebiotics are dietary substances that affect the host by stimulating growth and/or activity of potentially health promoting bacteria. The aims of this study were to investigate whether prebiotics can prevent colitis in SPF HLA‐B27 rats, and secondly, to explore mechanisms of protection. SPF HLA‐B27 transgenic rats received orally the prebiotic combination long‐chain inulin and oligofructose (Synergy 1), or not, prior to the development of clinically detectable colitis. After seven weeks, cecal and colonic tissues were collected for gross cecal scores (GCS), histologic inflammatory scores (scale 0‐4), and mucosal cytokine measurement. Cecal and colonic contents were collected for analysis of the gut microbiota by PCR‐denaturing gradient gel electrophoresis (PCR‐DGGE) and fluorescent in‐situ hybridization (FISH), and analysis of short‐chain fatty acid composition. Prebiotic treatment significantly decreased GCS and inflammatory histologic scores in the cecum and colon. Prebiotic treatment also decreased cecal IL‐1&bgr;, but increased cecal TGF‐&bgr; concentrations. Inulin/oligofructose altered the cecal and colonic PCR‐DGGE profiles, and FISH analysis showed significant increases in cecal Lactobacillus and Bifidobacterium populations after prebiotic treatment compared with water‐treated rats. In conclusion, the prebiotic combination Synergy 1 reduced colitis in HLA‐B27 transgenic rats, which effect was associated with alterations to the gut microbiota, decreased tissue proinflammatory cytokines and increased immunomodulatory molecules. These results show promise for prebiotics as primary or adjuvant maintenance therapy for chronic inflammatory bowel diseases.

Systematic review: faecal transplantation for the treatment of Clostridium difficile-associated disease

Management of recurrent Clostridium difficile‐associated disease (CDAD), particularly in elderly patients, remains clinically challenging. Faecal transplantation (FT) may restore normal microbiota and break the cycle of recurrent CDAD.

Helicobacter hepaticus Does Not Induce or Potentiate Colitis in Interleukin-10-Deficient Mice

ABSTRACT Helicobacter hepaticus has been reported to induce colitis, hepatitis, and hepatocellular carcinoma in several different murine models. The aim of this study was to determine if H. hepaticus will cause colitis in monoassociated mice lacking the interleukin-10 gene (IL-10−/− mice) and potentiate colitis in specific-pathogen-free (SPF) IL-10−/− mice. Germfree IL-10−/− mice on either a mixed (C57BL/6 × 129/Ola) or inbred (129/SvEv) genetic background were monoassociated with H. hepaticus ATCC 51448 by oral feeding and rectal enemas. In a second experiment, germfree IL-10−/− mice were colonized with stool from SPF mice that harbored or did not harbor endogenous H. hepaticus. After 7 to 9 weeks of colonization, weight loss and mortality were assessed, the colon was isolated for histology and IL-12 secretion, and mesenteric lymph node cells were assessed for T-cell activation markers. It was found that IL-10−/− mice monoassociated with H. hepaticus for up to 16 weeks showed almost no histologic colitis or increased IL-12 production. SPF IL-10-knockout mice had no significant difference in weight loss, mortality rate, histologic scores, colonic IL-12 secretion, or T-cell activation with or withoutH. hepaticus. We conclude that H. hepaticusdoes not induce or potentiate disease in our IL-10−/−mice and therefore is not required to induce colitis in genetically susceptible hosts.