Harnessing murine models of Crohn's disease ileitis to advance concepts of pathophysiology and treatment.

Crohn's disease (CD) and ulcerative colitis (UC) are both characterized by chronic inflammation and severe dysfunction of the gastrointestinal tract. These two forms of inflammatory bowel disease (IBD) represent distinct clinical disorders with diverse driving mechanisms; however, this divergence is not reflected in currently approved therapeutics that commonly target general proinflammatory pathways. A compelling need therefore remains to understand factors that differentiate the topology and the distinct clinical manifestations of CD versus UC, in order to develop more effective and specialized therapies. Animal models provide valuable platforms for studying IBD heterogeneity and deciphering disease-specific mechanisms. Both the established and the newly developed ileitis mouse models are characterized by various disease initiating mechanisms and diverse phenotypic outcomes that reflect the complexity of human CD-ileitis. Microbial dysbiosis, destruction of epithelial barrier integrity, immune cell deregulation, as well as the recently described genome instability and stromal cell activation have all been proposed as the triggering factors for the development of ileitis-associated pathology. In this review, we aim to critically evaluate the mechanistic underpinnings of murine models of CD-ileitis, discuss their phenotypic similarities to human disease, and envisage their further exploitation for the development of novel targeted and personalized therapeutics.

Deoxycholic acid enhancement of lymphocyte migration through direct interaction with the intestinal vascular endothelium.

BACKGROUND AND AIM: The small intestine plays a central role in gut immunity, and enhanced lymphocyte migration is involved in the pathophysiology of various enteropathy. Bile acid (BA) is closely related to lipid metabolism and gut microbiota and essential for gut homeostasis. However, the effects of BA on gut immunity have not been studied in detail, especially on the small intestine and lymphocyte migration. Therefore, we aimed to investigate the effect of BA on small intestinal lymphocyte microcirculation. METHODS: The effect of deoxycholic acid (DCA), taurocholic acid (tCA), or cholic acid (CA) on the indomethacin (IND)-induced small intestinal enteropathy in mice was investigated. Lymphocyte movements were evaluated after exposure to BA using intravital microscopy. The effects of BA on surface expression of adhesion molecules on the vascular endothelium and lymphocytes through BA receptors were examined in vitro. RESULTS: IND-induced small intestinal enteropathy was histologically aggravated by DCA treatment alone. The expression of adhesion molecules ICAM-1 and VCAM-1 was significantly enhanced by DCA. Exposure to DCA increased lymphocyte adhesion in the microvessels of the ileum, which was partially blocked by anti-α4ß1 integrin antibody in vivo. The expression of ICAM-1 and VCAM-1 was significantly enhanced by DCA in vitro, which was partially suppressed by the sphingosine-1-phosphate receptor 2 (S1PR2) antagonist. The S1PR2 antagonist significantly ameliorated IND-induced and DCA-exaggerated small intestinal injury. CONCLUSION: DCA exacerbated IND-induced small intestinal enteropathy. DCA directly acts on the vascular endothelium and enhances the expression levels of adhesion molecules partially via S1PR2, leading to enhanced small intestinal lymphocyte migration.

Short- and Long-term Outcomes Following Side-to-side Strictureplasty and its Modification Over the Ileocaecal Valve for Extensive Crohn's Ileitis.

BACKGROUND AND AIMS: Postoperative recurrence remains a challenging problem in patients with Crohn's disease [CD]. To avoid development of short bowel syndrome, strictureplasty techniques have therefore been proposed. We evaluated short- and long-term outcomes of atypical strictureplasties in CD patients with extensive bowel involvement. METHODS: Side-to-side isoperistaltic strictureplasty [SSIS] was performed according to the Michelassi technique or modification of this over the ileocaecal valve [mSSIS]. Ninety-day postoperative morbidity was assessed using the comprehensive complication index [CCI]. Clinical recurrence was defined as symptomatic, endoscopically or radiologically confirmed, stricture/inflammatory lesion requiring medical treatment or surgery. Surgical recurrence was defined as the need for any surgical intervention. Endoscopic remission was defined as ≤i1, according to the modified Rutgeerts score. Deep remission was defined as the combination of endoscopic remission and absence of clinical symptoms. Perioperative factors related to clinical recurrence were evaluated. RESULTS: A total of 52 CD patients [SSIS n = 12; mSSIS n = 40] were included. No mortality occurred. Mean CCI was 10.3 [range 0-33.7]. Median follow-up was 5.9 years [range 0.8-9.9]. Clinical recurrence [19 patients] was 29.7% and 39.6% after 3 and 5 years, respectively. Surgical recurrence [seven patients] was 2% and 14.1% after 3 and 5 years, respectively. At the end of the follow-up, 92% of patients kept the original strictureplasty and deep remission was observed in 25.7% of the mSSIS patients. None of the perioperative variables considered showed a significant association with clinical recurrence. CONCLUSIONS: SSIS is safe, effective, and provides durable disease control in patients with extensive CD ileitis.

A plethora of manifestations following a Mycoplasma pneumoniae infection: a case report.

Mycoplasma pneumoniae infection can present with a plethora of symptoms and result in a systemic vasculitis by activating a cascade of autoimmune reactions. In this case report, a young man without relevant past medical history was admitted to the hospital with diarrhea, abdominal pain and spiking fever. A CT-scan showed terminal ileitis. A 5-day broad spectrum antibiotic treatment (ciprofloxacin/clindamycin) did not result in any clinical improvement. On the contrary, the patient developed a cholestatic hepatitis, bilateral anterior uveitis and a dry cough. Extensive serological testing finally led to the diagnosis of a M. pneumoniae infection by paired serology (≥4-fold rise in IgG titer). In the diagnostic work-up, a PET-CT was performed and showed increased tracer uptake in the carotids and vertebral arteries, suggesting the diagnosis of vasculitis. After start of azithromycin and low-dose corticosteroids (0.5 mg/kg/day), a gradual clinical and biochemical improvement was observed. But subsequently, the patients relapsed and presented with an acute coronary syndrome. Coronary angiography revealed aneurysmatic deformation of the three coronary arteries, leading to the assumption of coronary vasculitis. Clinical improvement was achieved with high-dose corticosteroids (1 mg/kg/day). This case shows that M. pneumoniae is not merely a pulmonary infection, but that its primary symptoms can be diverse and misleading. All clinicians should be aware of its extrapulmonary manifestations.

[Purulent peritonitis due to gonococcal infection]. / Purulente peritonitis door een gonokokkeninfectie.

BACKGROUND A Neisseria gonorrhoea infection is one of the most common sexually transmitted diseases and can present both urogenitally and extragenitally. CASE DESCRIPTION A 55-year-old woman presented at the emergency room with general malaise, abdominal pain and fever. Despite extensive surgical, gynaecological and radiological investigations no clear cause could initially be found. She was subsequently admitted to the surgical unit for observation. During the admission period the patient developed diffuse peritonitis and her infection parameters were rising. Diagnostic laparoscopy revealed extensive terminal ileitis with a reactive infiltrate of the uterine fundus and purulent peritonitis. A PCR test of the abdominal exudate was strongly positive for Neisseria gonorrhoeae, but cultures remained negative. Following an 8-day course of antibiotic treatment with intravenous ceftriaxone, the patient recovered from her symptoms. CONCLUSION Terminal ileitis with peritonitis is an unusual extragenital manifestation of a gonococcal infection. In order to make a diagnosis, surgical exploration with cultures is sometimes indicated.

Late-onset Crohn's disease: a comparison of disease behaviour and therapy with younger adult patients: the Italian Group for the Study of Inflammatory Bowel Disease 'AGED' study.

BACKGROUND: Disease phenotype and outcome of late-onset Crohn's disease are still poorly defined. METHODS: In this Italian nationwide multicentre retrospective study, patients diagnosed ≥65 years (late-onset) were compared with young adult-onset with 16-39 years and adult-onset Crohn's disease 40-64 years. Data were collected for 3 years following diagnosis. RESULTS: A total of 631 patients (late-onset 153, adult-onset 161, young adult-onset 317) were included. Colonic disease was more frequent in late-onset (P < 0005), stenosing behaviour was more frequent than in adult-onset (P < 0003), but fistulising disease was uncommon. Surgery rates were not different between the three age groups. Systemic steroids were prescribed more frequently in young adult-onset in the first year, but low bioavailability steroids were used more frequently in late-onset in the first 2 years after diagnosis (P < 0.036, P < 0.041, respectively). The use of immunomodulators and anti-TNF's even in patients with more complicated disease, that is, B2 or B3 behaviour (Montreal classification), remained significantly inferior (P < 0.0001) in late-onset compared to young adult-onset. Age at diagnosis, Charlson comorbidity index, and steroid used in the first year were negatively associated with the use of immunomodulators and biologics. Comorbidities, related medications and hospitalizations were more frequent in late-onset. Polypharmacy was present in 56% of elderly Crohn's disease patients. CONCLUSION: Thirty-two percent of late-onset Crohn's disease presented with complicated disease behaviour. Despite a comparable use of steroids and surgery, immunomodulators and biologics were used in a small number of patients.

Should We Divide Crohn's Disease Into Ileum-Dominant and Isolated Colonic Diseases?

Crohn's disease (CD) is an inflammatory bowel disease that can involve any region of the gastrointestinal tract. First described in 1932 as terminal ileitis or regional enteritis, it predominately involves the ileum with or without colonic involvement. Isolated colonic CD was first described in 1960 and since then the phenotypic classification of CD has evolved to stratify patients into isolated ileal, ileocolonic, or isolated colonic involvement. In the current review we evaluate the published literature regarding differences in epidemiology, natural history, pathogenesis, response to therapy, and disease monitoring, when stratified by disease location. Based on the available evidence consideration could be given to a new classification for CD, which splits it into ileum dominant (isolated ileal and ileocolonic) and isolated colonic disease. This may allow for a more optimized approach to clinical care and scientific research for CD.

Chronic Kidney Disease Elicits an Intestinal Inflammation Resulting in Intestinal Dysmotility Associated with the Activation of Inducible Nitric Oxide Synthesis in Rat.

This study was conducted to investigate whether chronic kidney disease (CKD) affects intestinal inflammation and intestinal motility and the underlying mechanisms. Rats were randomized into control group and uremic group. Uremia rats were induced by the 5/6 kidney resection, while the control went through the same procedures but without any kidney resection. Intestinal motility was assessed by charcoal transport assay; intestinal inflammation was assessed by analyses of levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 in the ileum tissue. The inducible nitric oxide synthesis (iNOS) activity was assessed in the ileum tissue. The results showed that the intestinal motility in uremic group was significantly decreased compared with that in the control group on postoperative weeks 8 and 10. Meanwhile, the uremic group presented significantly higher concentrations of TNF-α, IL-6, and IL-10 than control group on postoperative weeks 8 and/or 10, and higher gene expression on postoperative weeks 6, 8, and 10. Furthermore, the intestinal iNOS activity in the uremic group was significantly increased compared with that in control group on postoperative weeks 8 and 10. These results suggest that CKD could induce intestinal inflammation and lead to intestinal dysmotility, which may be associated with iNOS activation in the intestine.

Case report of a pair of siblings with cryptogenic multifocal ulcerating stenosing enteritis: A rare disease easily to be misdiagnosed as Crohn disease.

RATIONALE: The rare disease cryptogenic multifocal ulcerous stenosing enteritis (CMUSE) is characterized by multiple and recurring small intestinal ulcers with stenosis of unknown causes. In clinic, it is difficult to be differentiated from the inflammatory bowel disease, especially the Crohn disease. PATIENT CONCERNS: Here we report a pair of siblings who suffered from long-time anemia and abdominal pain and misdiagnosed with inflammatory bowel disease (IBD) for many years. DIAGNOSES: They were finally diagnosed with CMUSE with intestinal obstruction. INTERVENTIONS AND OUTCOMES: They both accepted surgical treatment and recovered well. No abdominal symptom appeared in the two-year follow-up. LESSONS: This report underscores that CMUSE patients may have a long course of suffering from anemia and abdominal pain, normal inflammatory markers and normal colon, and sometimes have a family history of CMUSE. Surgery of segmental bowel resection is a good way to solve intractable intestinal obstruction in CMUSE.

Physiological relevance of food grade microcapsules: Impact of milk protein based microcapsules on inflammation in mouse models for inflammatory bowel diseases.

In order to increase beneficial effects of bioactive compounds in functional food and dietary supplements, enormous efforts are put in the technological development of microcapsules. Although these products are often tailor-made for disease susceptible consumer, the physiological impact of microcapsule uptake on the respective target consumer has never been addressed. The present study aimed to assess the relevance of this aspect by analyzing the impact of milk protein based microcapsules on experimental inflammatory bowel disease. Long-term feeding of sodium caseinate or rennet gel microcapsules resulted in significant alterations in the intestinal microbiota of healthy mice. In TNFΔARE/wt mice, a model for chronic ileal inflammation, rennet gel microcapsules resulted in further increased splenomegaly, whereas ileal inflammation was unchanged. In IL10(-/-) mice, a model for chronic colitis, both types of microcapsules induced a local increase of the intestinal inflammation. The present study is the first to demonstrate that, independent of their cargo, microcapsules have the potential to affect the intestinal microbiota and to exert unprecedented detrimental effects on disease-susceptible individuals. In conclusion, the impact of microcapsule uptake on the respective target consumer groups should be thoroughly investigated in advance to their commercial use in functional food or dietary supplements.

A prospective 12-week mucosal healing assessment of small bowel Crohn's disease as detected by capsule endoscopy.

BACKGROUND: Mucosal healing is increasingly recognized as an important treatment goal in Crohn's disease (CD). Data from colonic disease shows improved long-term outcomes in patients achieving complete mucosal healing. Little is currently known of this with respect to ileitis, which is increasingly diagnosed using small bowel capsule endoscopy. The study aimed to prospectively assess mucosal healing and deep remission rates in a cohort of symptomatic small bowel CD patients commencing biologic or immunomodulator therapy. METHODS: Baseline demographics, quality of life questionnaires and Harvey-Bradshaw index were collected along with C-reactive protein and calprotectin. Capsule endoscopy Crohn's disease activity (CECDAI) index was used to assess ileitis severity. All parameters were reassessed at week 12. Results at baseline and week 12 were compared using two-tailed Wilcoxon analysis, P value less than 0.05 was considered significant. RESULTS: In total, 43 patients of 71 screened underwent 80 small bowel capsule endoscopies. On the basis of the CECDAI, 39 (90%) demonstrated active small bowel CD at baseline with 37 (86%) undergoing 12-week assessment. Overall there was a statistically significant symptomatic and biochemical improvement at week 12. Furthermore, 10 (27%) had demonstrated a normalization in CECDAI (<3.5), which was statistically significant (P<0.0005, 95% confidence interval 0.12-0.15). However, no patient had achieved full mucosal healing. CONCLUSION: In patients with active small bowel CD early symptomatic and biochemical response to treatment is not mirrored by mucosal healing. Repeat mucosal healing assessment in this cohort is warranted following a longer duration of treatment to identify potential mucosal healing and deep remission rates.

Correlation between morphological expansion and impairment of intra- and prelesionary motility in inflammatory small bowel lesions in patients with Crohn's disease - preliminary data.

INTRODUCTION: The aim of this study is to investigate if alterations of intra- and prelesionary motility in inflamed small-bowel segments correlate with length, wall-thickness and prelesionary dilatation of inflammatory small bowel lesions in patients suffering from Crohn's disease assessed with MRI. METHODS AND MATERIALS: This retrospective IRB approved study included 25 patients (12 males, 18-77y) with inflammatory lesions examined using (MRE) magnetic resonance imaging enterography. Cine MRE was performed using a coronal 2D steady-state free precession sequence (TR 2.9, TE 1.25) on a 1.5T MRI scanner. Small bowel motility was examined using a dedicated MR-motility assessment software (Motasso, Vers. 1.0, Sohard AG, Bern, Switzerland). Motility patterns (contraction frequency, relative occlusion rate and mean diameter) were assessed in correlation to wall thickness, length and prelesionary dilatation of the lesions. Statistical analysis was performed by calculation of the Pearson's-Correlation coefficient. RESULTS: The length of the inflammatory segments, the wall thickening and prelesionary dilatation did not correlate with the frequency of the contractions (r=0.17, p=0.477; r=0.316, p=0.123; r=0.161, p=0.441) or the impairment of luminal occlusion (r=0.274, p=0.184; r=0.199, p=.0339; r=0.015, p=0.945) and only the prelesionary dilatation (r=0.410, p=0.042) correlated to the mean luminal diameter of the segment. CONCLUSION: The degree of motility impairment within inflammatory small bowel lesions does not significantly correlate with the extent of the lesion but with the motility measured in prelesionary, non-affected segments, suggesting an interdependent functional aspect of inflammation even in morphologically non-affected small bowel segments.

Loss of estrogen-mediated immunoprotection underlies female gender bias in experimental Crohn's-like ileitis.

The incidence and severity of Crohn's disease (CD) are increased in female patients. Using SAMP1/YitFc (SAMP) mice, a spontaneous model of chronic intestinal inflammation that displays histologic and pathogenic similarities to human CD, we investigated the potential mechanism(s) contributing to sex differences observed in CD. Similar to gender differences observed in CD patients, SAMP female (SAMP-F) mice displayed an earlier onset and more severe ileitis compared with SAMP male (SAMP-M) mice. Furthermore, T-regulatory cells (Tregs) from gut-associated lymphoid tissue (GALT) of SAMP-F mice were reduced in frequency and impaired in their in vitro and in vivo suppressive functions compared with that of SAMP-M mice. Given the interaction between sex hormones and Treg function, we investigated the possible role of estrogen (E2) in SAMP ileitis. SAMP-M mice responded to exogenous E2 administration by expanding Treg frequency and reducing ileal inflammation, whereas SAMP-F mice were resistant. Conventional T cells and Tregs responded differentially to estrogen signaling, leading to distinct immunoprotective effects mediated by distinct estrogen receptor (ER) isoforms. These mechanisms were impaired in T cells from SAMP-F mice. Thus, hormone signaling influences the expansion and function of GALT Tregs in an ER-dependent manner and contributes to gender-based differences in experimental CD.

Anti-IL-6 antibody treatment but not IL-6 knockout improves intestinal barrier function and reduces inflammation after binge ethanol exposure and burn injury.

Interleukin 6 (IL-6) is an inflammatory cytokine known to be elevated in chronic diseases and after insults such as trauma and infection. Although necessary for the development of B cells and Th17 cells, IL-6, at elevated levels, can also cause tissue damage and lead to a rise in inflammation. Previous work in our laboratory has shown that IL-6 is increased both systemically and in multiple organ systems including the ileum after ethanol exposure and burn injury. As this combined insult causes elevated intestinal morphological damage, tight junction protein localization alterations, and phosphorylated myosin light chain levels, we sought to determine the role of IL-6 in these intestinal responses using a model of binge ethanol exposure and burn injury. Interleukin 6 antibody treatment after the combined insult reduced morphological changes in the ileum, bacterial translocation, and phosphorylated myosin light chain levels relative to either injury alone. Zonula occludens protein 1 and occludin localization was also reestablished in wild-type mice given IL-6 antibody after ethanol and burn. Interleukin 6-knockout mice given ethanol and burn injury also had reduced intestinal damage; however, no changes in bacterial translocation or tight junction protein localization were observed as compared with similarly treated wild-type mice. These data suggest that IL-6 may have a role in intestinal tissue damage observed after the combined insult of binge ethanol exposure and burn injury, although complete loss of IL-6 does not seem to be beneficial in this model. Modulation of IL-6 may present a new option for preventing intestinal damage and associated inflammation after a combined insult of ethanol exposure and burn injury.

Involvement of the NO-cGMP-K(ATP) channel pathway in the mesenteric lymphatic pump dysfunction observed in the guinea pig model of TNBS-induced ileitis.

Mesenteric lymphatic vessels actively transport lymph, immune cells, fat, and other macromolecules from the intestine via a rhythmical contraction-relaxation process called lymphatic pumping. We have previously demonstrated that mesenteric lymphatic pumping was compromised in the guinea pig model of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced ileitis, corroborating clinical and experimental observations of a dilated and/or obstructed phenotype of these vessels in inflammatory bowel disease. Many mediators released during the inflammatory process have been shown to alter lymphatic contractile activity. Among them, nitric oxide (NO), an inflammatory mediator abundantly released during intestinal inflammation, decreases the frequency of lymphatic contractions through activation of ATP-sensitive potassium (K(ATP)) channels. The objective of this study was to investigate the role of NO and K(ATP) channels in the lymphatic dysfunction observed in the guinea pig model of TNBS-induced ileitis. Using quantitative real-time PCR, we demonstrated that expression of Kir6.1, SUR2B, and inducible NO synthase (iNOS) mRNAs was significantly upregulated in TNBS-treated animals. Pharmacological studies performed on isolated, luminally perfused mesenteric lymphatic vessels showed that the K(ATP) channels blocker glibenclamide, the selective iNOS inhibitor 1400W, and the guanylyl cyclase inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one) significantly improved lymphatic pumping in quiescent lymphatic vessels from TNBS-treated animals. Membrane potential measurement with intracellular microelectrodes revealed that vessels from TNBS-treated animals were hyperpolarized compared with their sham counterpart and that the hyperpolarization was significantly attenuated in the presence of glibenclamide and ODQ. Our findings suggest that NO and K(ATP) play a major role in the lymphatic contractile dysfunction that occurred as a consequence of the intestinal inflammation caused by TNBS.

Inhibitory effect of cannabichromene, a major non-psychotropic cannabinoid extracted from Cannabis sativa, on inflammation-induced hypermotility in mice.

BACKGROUND AND PURPOSE: Cannabichromene (CBC) is a major non-psychotropic phytocannabinoid that inhibits endocannabinoid inactivation and activates the transient receptor potential ankyrin-1 (TRPA1). Both endocannabinoids and TRPA1 may modulate gastrointestinal motility. Here, we investigated the effect of CBC on mouse intestinal motility in physiological and pathological states. EXPERIMENTAL APPROACH: Inflammation was induced in the mouse small intestine by croton oil. Endocannabinoid (anandamide and 2-arachidonoyl glycerol), palmitoylethanolamide and oleoylethanolamide levels were measured by liquid chromatography-mass spectrometry; TRPA1 and cannabinoid receptors were analysed by quantitative RT-PCR; upper gastrointestinal transit, colonic propulsion and whole gut transit were evaluated in vivo; contractility was evaluated in vitro by stimulating the isolated ileum, in an organ bath, with ACh or electrical field stimulation (EFS). KEY RESULTS: Croton oil administration was associated with decreased levels of anandamide (but not 2-arachidonoyl glycerol) and palmitoylethanolamide, up-regulation of TRPA1 and CB1 receptors and down-regulation of CB2 receptors. Ex vivo CBC did not change endocannabinoid levels, but it altered the mRNA expression of TRPA1 and cannabinoid receptors. In vivo, CBC did not affect motility in control mice, but normalized croton oil-induced hypermotility. In vitro, CBC reduced preferentially EFS- versus ACh-induced contractions. Both in vitro and in vivo, the inhibitory effect of CBC was not modified by cannabinoid or TRPA1 receptor antagonists. CONCLUSION AND IMPLICATIONS: CBC selectively reduces inflammation-induced hypermotility in vivo in a manner that is not dependent on cannabinoid receptors or TRPA1.

Innate dysfunction promotes linear growth failure in pediatric Crohn's disease and growth hormone resistance in murine ileitis.

BACKGROUND: Growth failure remains a common complication of pediatric Crohn's disease (CD) and has been associated with small bowel involvement and need for surgery. We have reported that patients with elevated (≥ 1.6 µg/mL) granulocyte macrophage colony stimulating factor autoantibodies (GM-CSF Ab) are more likely to experience complicated ileal disease requiring surgery. We hypothesized that concurrent GM-CSF Ab and CARD15 risk allele carriage (C15(+) GMAb(+) ) would be associated with growth failure in CD and growth hormone (GH) resistance in murine ileitis. METHODS: We enrolled 229 pediatric CD patients at two sites and determined CARD15 genotype, serum GM-CSF Ab, and GH binding protein (GHBP), and height (HTz) and weight (WTz) z-scores at diagnosis. Ileitis was induced in card15-deficient mice by GM-CSF neutralization and nonsteroidal antiinflammatory drug (NSAID) exposure. Hepatic GH receptor (GHR) abundance and GH-dependent Stat5 activation were determined by western blot and Igf-I mRNA expression by real-time polymerase chain reaction (PCR). RESULTS: Mean (95% confidence interval [CI]) HTz at diagnosis was reduced to -0.48 (-4.2, 2.3) in C15(+) GMAb(+) patients, compared to -0.07 (-4.9, 3.4) in disease controls (P ≤ 0.05). Circulating GHBP, as a marker for tissue GHR abundance, was reduced in C15(+) GMAb(+) patients. Hepatic GHR abundance, GH induction of Stat5 tyrosine phosphorylation, and Igf-I mRNA expression were reduced in male card15-deficient mice with ileitis due to GM-CSF neutralization and NSAID exposure. CONCLUSIONS: Innate dysfunction due to concurrent genetic variation in CARD15 and neutralizing GM-CSF Ab is associated with linear growth failure in pediatric CD, and hepatic GH resistance in murine ileitis.

CCR3 Blockade Attenuates Eosinophilic Ileitis and Associated Remodeling.

Intestinal remodeling and stricture formation is a complication of inflammatory bowel disease (IBD) that often requires surgical intervention. Although eosinophils are associated with mucosal remodeling in other organs and are increased in IBD tissues, their role in IBD-associated remodeling is unclear. Histological and molecular features of ileitis and remodeling were assessed using immunohistochemical, histomorphometric, flow cytometric, and molecular analysis (real-time RT-PCR) techniques in a murine model of chronic eosinophilic ileitis. Collagen protein was assessed by Sircol assay. Using a spontaneous eosinophilic Crohn's-like mouse model SAMP1/SkuSlc, we demonstrate an association between ileitis progression and remodeling over the course of 40 weeks. Mucosal and submucosal eosinophilia increased over the time course and correlated with increased histological inflammatory indices. Ileitis and remodeling increased over the 40 weeks, as did expression of fibronectin. CCR3-specific antibody-mediated reduction of eosinophils resulted in significant decrease in goblet cell hyperplasia, muscularis propria hypertrophy, villus blunting, and expression of inflammatory and remodeling genes, including fibronectin. Cellularity of local mesenteric lymph nodes, including T- and B-lymphocytes, was also significantly reduced. Thus, eosinophils participate in intestinal remodeling, supporting eosinophils as a novel therapeutic target.

Pathogenesis of gastritis in ileitis-prone SAMP1/Yit mice.

Inflammatory bowel disease is a chronic inflammatory disease of the gut which manifests as ulcerative colitis or Crohn's disease. One of the most studied animal models of spontaneous Crohn's disease is the senescence-accelerated mouse (SAMP1/Yit strain) model. In SAMP1/Yit mice, although many immunological responses are perturbed, some evidence suggests that the primary defect lies in the epithelial cell barrier. In the process of studying epithelial permeability, we observed that the stomach in SAMP1/Yit mice also had increased permeability. Upon further examination, these mice were shown to have marked, chronic gastritis with focal to diffuse aggregates of mononuclear cells of mixed lineages. These aggregates were located predominantly in the oxyntic mucosa, with occasional lesions in the forestomach but with relatively fewer cellular infiltrates in the antral mucosa. Real-time RT PCR showed an increase in several helper T cell (Th cell)-derived pro-inflammatory cytokines in the gastric mucosa of SAMP1/Yit mice. However, many of the cells in the aggregates of SAMP1/Yit mice were B cells. SAMP1/Yit B cells exacerbate ileitis when co-transferred into immunodeficient recipients. The gastritis also reflects a contribution by B cells. As SAMP1/Yit mice were derived from AKR mice, we examined AKR mice and determined that they too have an increased occurrence of gastritis, although they do not develop ileitis. B cells contributed to the gastric inflammation in these mice also. Thus, SAMP1/Yit mice display gastritis as well as ileitis, and B cells appear to play a role in the pathogenesis of inflammation at both sites. This review will discuss some of the mechanisms that may account for these different manifestations of gastrointestinal disease.