FGF21 Depletion Attenuates Colitis through Intestinal Epithelial IL-22-STAT3 Activation in Mice

Fibroblast growth factor 21 (FGF21) is a glucose and lipid metabolic regulator. Recent research revealed that FGF21 was also induced by inflammatory stimuli. Its role in inflammatory bowel disease (IBD) has not been investigated. In this study, an experimental IBD model was established in FGF21 knockout (KO) and wild-type (WT) mice by adding 2.5% (wt/vol) dextran sodium sulfate (DSS) to their drinking water for 7 days. The severity of the colitis and the inflammation of the mouse colon tissues were analyzed. In WT mice, acute DSS treatment induced an elevation in plasma FGF21 and a significant loss of body weight in a time-dependent manner. Surprisingly, the loss of body weight and the severity of the colitis induced by DSS treatment in WT mice were significantly attenuated in FGF21 KO mice. Colon and circulating pro-inflammatory factors were significantly lower in the FGF21 KO mice compared to the WT mice. As shown by BrdU staining, the FGF21 KO mice demonstrated increased colonic epithelial cell proliferation. DSS treatment reduced intestinal Paneth cell and goblet cell numbers in the WT mice, and this effect was attenuated in the FGF21 KO mice. Mechanistically, FGF21 deficiency significantly increased the signal transducer and activator of transcription (STAT)-3 activation in intestinal epithelial cells and increased the expression of IL-22. Further study showed that the expression of suppressor of cytokine signaling-2/3 (SOCS 2/3), a known feedback inhibitor of STAT3, was significantly inhibited in the DSS-treated FGF2 KO mice compared to the WT mice. We conclude that FGF21 deficiency attenuated the severity of DSS-induced acute colitis, which is likely mediated by enhancing the activation of the IL-22-STAT3 signaling pathway in intestinal epithelial cells.

Enhancement of gut barrier function by microbial metabolite, urolithin A via AhR-Nrf2 dependent pathways in IBD

Inflammatory bowel diseases (IBD) consisting of Crohn’s and ulcerative colitis are resultant of dysregulation of the immune system leading to intestinal inflammation and microbial dysbiosis. Numerous studies in recent years highlighted the pivotal role of gut microbiota and their metabolites in host physiological processes including in IBD. Urolithin A (UroA) is a microbial metabolite derived from polyphenolics (e.g., ellagitannins/ellagic acid) of pomegranate and berries. We also synthesized a potent structural analogue of UroA (UAS03) and tested their efficacies in preventing and treating colitis in pre-clinical models. Our studies showed that UroA/UAS03 significantly enhance gut barrier function in addition to blocking unwarranted inflammation. We demonstrate that UroA and UAS03 exert their barrier functions through activation of aryl hydrocarbon receptor (AhR)- nuclear factor erythroid 2–related factor 2 (Nrf2)-dependent pathways to upregulate epithelial tight junction proteins. In addition, treatment with these compounds attenuated colitis in pre-clinical models by remedying barrier dysfunction and blocking increased inflammatory mediators such as IL-6, TNF-α and IL-1β. UroA/UAS03 failed to induce tight junction proteins and protect against 2,4,6-Trinitrobenzenesulfonic acid (TNBS)-induced colitis in AhR−/− and Nrf2−/− mice suggesting an obligatory requirement of AhR and Nrf2 pathways for UroA/UAS03 mediated beneficial activities. Overall, the results highlight how microbial metabolites provide two-pronged beneficial activities at gut epithelium by enhancing barrier functions and reducing systemic and local inflammation to protect from colonic diseases.

Methotrexate Is Not Superior to Placebo in Maintaining Steroid-Free Response or Remission in Ulcerative Colitis

BACKGROUND & AIMS

Parenteral methotrexate induces clinical remission but not endoscopic improvement of mucosal inflammation in patients with ulcerative colitis (UC). We performed a randomized, placebo-controlled trial to assess the efficacy of parenteral methotrexate in maintaining steroid-free response or remission in patients with UC after induction therapy with methotrexate and steroids.

METHODS

We performed a 48-week trial, from February 2012 through May 2016, of 179 patients with active UC (Mayo score of 6-12 with endoscopy subscore ≥ 2) despite previous conventional or biological therapy. The study comprised a 16-week open label methotrexate induction period followed by a 32-week double-blind, placebo-controlled maintenance period. Patients were given subcutaneous methotrexate (25 mg/wk) and a 12-week steroid taper. At week 16, steroid-free responders were randomly assigned to groups that either continued methotrexate (25 mg/wk, n = 44) or were given placebo (n = 40) until week 48. We compared the efficacy of treatment by analyzing the proportion of patients who remained relapse free and were in remission at week 48 without use of steroids or other medications to control disease activity.

RESULTS

Ninety-one patients (51%) achieved response at week 16, and 84 patients were included in the maintenance period study. During this period, 60% of patients in the placebo group (24/40) and 66% in the methotrexate group (29/44) had a relapse of UC (P = .75). At week 48, 30% of patients in the placebo group (12/40) and 27% of patients in the methotrexate group (12/44) were in steroid-free clinical remission without need for additional therapies (P = .86). No new safety signals for methotrexate were detected.

CONCLUSIONS

Parenteral methotrexate (25 mg/wk) was not superior to placebo in preventing relapses of UC in patients who achieved steroid-free response during induction therapy. ClinicalTrials.gov, Number: NCT01393405.

Clinical Efficacy of Serum-Derived Bovine Immunoglobulin in Patients With Refractory Inflammatory Bowel Disease

BACKGROUND

Inflammatory bowel disease (IBD) can have autoimmunity and/or intestinal barrier dysfunction as part of pathophysiology and may be refractory to all available treatment options. Serum-derived bovine immunoglobulin (SBI) binds microbial components with postulated downstream effects of normalized gut immune and barrier function, which may be useful for managing IBD. The purpose of our study was to evaluate the effectiveness of SBI in the management of refractory IBD, particularly symptoms of chronic diarrhea and loose stools.

METHODS

We retrospectively analyzed charts for patients diagnosed with IBD (n = 40) who were refractory to standard treatment. Patients received oral SBI 5 g daily for a period of at least 6 weeks. Twelve patients with IBD fulfilled study inclusion criteria. Each patient graded the severity and frequency of gastrointestinal symptoms before starting SBI and at 6 weeks of treatment using a standardized patient assessment form. Means and standard deviations for all symptom scores at baseline and week 6 of treatment were analyzed.

RESULTS

Mean symptom scores decreased significantly for nausea (P = 0.02 for severity and P = 0.03 for mean symptom score) and diarrhea (P = 0.0006, P = 0.0001 and P = 0.0001 for severity, frequency and mean symptom score, respectively).

CONCLUSIONS

Therapy with SBI alleviated some refractory gastrointestinal symptoms in patients with IBD, including nausea and diarrhea. Increased duration, dosage and/or frequency of SBI might provide additional symptom improvement and could be tested through controlled clinical trials with larger sample sizes and longer follow-up.

Immunopathophysiology of inflammatory bowel disease: how genetics link barrier dysfunction and innate immunity to inflammation

Inflammatory bowel diseases (IBD) comprise a distinct set of clinical symptoms resulting from chronic or relapsing immune activation and corresponding inflammation within the gastrointestinal (GI) tract. Diverse genetic mutations, encoding important aspects of innate immunity and mucosal homeostasis, combine with environmental triggers to create inappropriate, sustained inflammatory responses. Recently, significant advances have been made in understanding the interplay of the intestinal epithelium, mucosal immune system, and commensal bacteria as a foundation of the pathogenesis of inflammatory bowel disease. Complex interactions between specialized intestinal epithelial cells and mucosal immune cells determine different outcomes based on the environmental input: the development of tolerance in the presence of commensal bacterial or the promotion of inflammation upon recognition of pathogenic organisms. This article reviews key genetic abnormalities involved in inflammatory and homeostatic pathways that enhance susceptibility to immune dysregulation and combine with environmental triggers to trigger the development of chronic intestinal inflammation and IBD.

Refractory pouchitis improves after administration of the green tea polyphenol EGCG: a retrospective review

INTRODUCTION

Ulcerative colitis (UC) is a common, chronic, inflammatory process limited to the colon. UC affects up to 1 million individuals in the USA alone and requires resection in up to 30% of patients. Resection is often followed by creation of a pouch. Pouchitis is the most common complication of ileal pouch-anal anastomosis (IPAA) following total proctocolectomy, affecting up to 50% of patients. Symptoms include increased stool frequency, urgency, cramping, and bleeding. Management of pouchitis is complex in antibiotic refractory cases. Plant-based polyphenolic compounds have shown protective effects against UC. We conducted a retrospective review of pouchitis patients treated with EGCG 200-400 mg twice daily.

RESULTS

Seven of nine (78%) patients experienced significant improvement based on reduced frequency of bowel movements and bleeding, while five of nine (56%) experienced complete relief. One patient experienced no improvement with EGCG, and one had progression of pouchitis symptoms while taking EGCG. No significant adverse events were noted by patients while taking EGCG.

DISCUSSION

The green tea-derived molecule EGCG exhibits an efficacy signal in the IBD-related condition of pouchitis. Impressively, 78% of patients experienced noticeable improvement in pouchitis symptoms after initiation of EGCG, while 56% of treated patients entered complete remission. These positive responses to EGCG in patients with pouchitis suggests the need to confirm these findings in a formal, controlled trial. Based on recent findings documenting its effects on epithelial permeability and mucosal inflammation, combined with its favorable safety profile, a possible preventative role could also be explored.

Abstract 1863: Non-invasive imaging of colitis using multispectral optoacoustic tomography

Background: Currently, several non-invasive modalities, including MRI and PET, are being investigated to identify early intestinal inflammation, longitudinally monitor disease status, or detect dysplastic changes in patients with inflammatory bowel disease (IBD). Currently, multispectral optoacoustic tomography (MSOT; often in combination with ultrasound) has been used to effectively image tumor xenografts as well as several orthotopic tumor models, including pancreatic adenocarcinoma, but not to specifically assess inflammatory or dysplastic changes in the bowel in murine models. Here, we assess the applicability and utility of (MSOT) in evaluating the presence and severity of colitis.

Methods: Nine 6-7 week old C57B/6 mice underwent antibiotic depletion of gastrointestinal flora before inoculation with enterotoxic Bacteroides fragilis to induce colitis. Mice were then anesthetized, depilated, imaged from their superior thorax to inferior pelvis using MSOT. Mice were evaluated prior to bacterial inoculation, 2 days after inoculation, and 7 days after inoculation. MSOT values for oxygenated and deoxygenated hemoglobin were determined using MSOT imaging software and compared using linear regression. At each timepoint, three mice underwent colonoscopy prior to euthanasia and colon processing for histology.

Results: Mice with bacterially-induced colitis demonstrated a temporally-associated increase in mesenteric and colonic vascularity, with an increase in mean signal intensity of oxygenated hemoglobin (1.150 vs. 2.716 MSOT a.u. compared to controls; p=0.004) by MSOT two days after inoculation. These findings were significantly more prominent 7 days after inoculation, with increased mean signal intensity of oxygenated hemoglobin (1.150 vs. 2.716 vs. 3.422 MSOT a.u. for controls vs. 2 days post-ETBF vs. 7 days post-ETBF, p=0.0002) and the development of punctate vascular lesions on the colonic surface. Compared to untreated controls, mice at 2 days and 7 days post ETBF inoculation demonstrated an increased colitis score on colonoscopy (1.5 vs. 2.5 vs. 5.5), which correlated well with MSOT findings of mean oxygenated hemoglobin signal intensity (r=0.82, p=0.013). These findings were also associated with inflammatory changes observed on histologic analysis.

Conclusions: MSOT represents a non-invasive diagnostic modality that effectively identifies colitis in a murine model. With improvements in depth of tissue penetration, MSOT may hold potential as a sensitive, accurate, non-invasive imaging tool in evaluation of both disease status and early detection of malignancy in patients with IBD.

Citation Format: Neal Bhutiani, William Grizzle, Susan Galandiuk, Dennis Otali, Gerald Dryden, Nejat Egilmez, Lacey R. Mcnally. Non-invasive imaging of colitis using multispectral optoacoustic tomography [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1863. doi:10.1158/1538-7445.AM2017-1863

Eldelumab [Anti-IP-10] Induction Therapy for Ulcerative Colitis: A Randomised, Placebo-Controlled, Phase 2b Study

BACKGROUND AND AIMS

Interferon-γ-inducible protein-10 [IP-10] mediates immune cell trafficking from the circulation to the inflamed colon and decreases gut epithelial cell survival. IP-10 expression is increased in patients with ulcerative colitis [UC]. We report efficacy and safety results from a dose-ranging induction study of eldelumab, a fully human monoclonal antibody to IP-10, in moderately to severely active UC.

METHODS

A total of 252 adults with UC [Mayo score ≥ 6 and endoscopic subscore ≥ 2] were randomised 1:1:1 to placebo or eldelumab 15 or 25 mg/kg administered intravenously on Days 1 and 8 and every other week thereafter. The primary endpoint was clinical remission [Mayo score ≤ 2; no individual subscale score > 1] at Week 11. Key secondary endpoints included Mayo score clinical response and mucosal healing at Week 11.

RESULTS

Neither eldelumab 15 or 25 mg/kg resulted in significant increases vs placebo in the proportion of patients achieving Week 11 clinical remission. Remission and response rates were 17.6% and 47.1% with eldelumab 25mg/kg, 13.1% and 44.0% with eldelumab 15mg/kg, and 9.6% and 31.3% with placebo. Clinical remission and response rates were higher in anti-tumour necrosis factor [TNF]-naïve patients treated with eldelumab compared with placebo. Eldelumab treatment was well tolerated and no immunogenicity was observed.

CONCLUSIONS

The primary endpoint was not achieved with induction treatment with eldelumab 15 or 25 mg/kg in patients with UC. Trends towards clinical remission and response were observed in the overall population and were more pronounced in anti-TNF naïve patients. Eldelumab safety signals were consistent with those reported previously [ClinicalTrials.gov number, NCT01294410].

COP9 regulates intestinal microbial ecology and susceptibility to colitis (MUC4P.839)

Inflammatory Bowel Disease (IBD) has been considered as the dysfunctional interplay between intestinal microbiota, epithelium and the immune system. Located at the heart of this complex interaction, intestinal epithelial cells (IECs) play a crucial role in coordinating commensal bacterial-dependent intestinal homeostasis. Separated from commensal bacteria by mucus layer, the mechanism that IECs confer a stable microbiota remains incompletely understood. Here, we reported that mice with an IEC-specific deletion of one subunit of COP9 signalosome, which regulates the ubiquitin-proteasome system, exhibited extreme susceptibility to dextran sulfate sodium (DSS) induced colitis. Deficiency of one subunit of COP9 resulted in dysfunction of paneth cell and colonic enterocyte, which led to impaired AMP (antimicrobial peptide) production, shifted composition of intestinal microbiota and skewed mucosal immune cells towards a proinflammatory phenotype. Deep sequencing and quantitative PCR analysis of luminal microbiota from proximal colon revealed a significant reduction of the relative abundance of Lactobacillus and increase of segmented filamentous bacteria. Correspondingly, the Th1/Th17 ratio is reversed in colonic lamina propria. Moreover, the susceptibility to colitis was alleviated by continued broad-spectrum antibiotic treatment. Collectively, these data suggest that COP9 signalosome in IEC regulates intestinal homeostasis by modulating the composition of microbiota.

Targeted drug delivery to intestinal macrophages by bioactive nanovesicles released from grapefruit

The gut mucosal immune system is considered to play an important role in counteracting potential adverse effects of food-derived antigens including nanovesicles. Whether nanovesicles naturally released from edible fruit work in a coordinated manner with gut immune cells to maintain the gut in a noninflammatory status is not known. Here, as proof of concept, we demonstrate that grapefruit-derived nanovesicles (GDNs) are selectively taken up by intestinal macrophages and ameliorate dextran sulfate sodium (DSS)-induced mouse colitis. These effects were mediated by upregulating the expression of heme oxygenase-1 (HO-1) and inhibiting the production of IL-1β and TNF-α in intestinal macrophages. The inherent biocompatibility and biodegradability, stability at wide ranges of pH values, and targeting of intestinal macrophages led us to further develop a novel GDN-based oral delivery system. Incorporating methotrexate (MTX), an anti-inflammatory drug, into GDNs and delivering the MTX-GDNs to mice significantly lowered the MTX toxicity when compared with free MTX, and remarkably increased its therapeutic effects in DSS-induced mouse colitis. These findings demonstrate that GDNs can serve as immune modulators in the intestine, maintain intestinal macrophage homeostasis, and can be developed for oral delivery of small molecule drugs to attenuate inflammatory responses in human disease.

Randomized, double-blind, placebo-controlled trial of the oral interleukin-12/23 inhibitor apilimod mesylate for treatment of active Crohn's disease

BACKGROUND

Interleukin-12 (IL-12) and interleukin-23 (IL-23) are inflammatory cytokines linked to the Th-1 and Th-17 phenotypes associated with Crohn's disease (CD). We investigated the activity and safety of apilimod mesylate (formerly STA-5326), an oral IL-12 and IL-23 inhibitor, in patients with active CD.

METHODS

We performed a multicenter, Phase 2, randomized, double-blinded, placebo-controlled study to evaluate the efficacy of apilimod mesylate in treating 220 adult patients with moderate-to-severe CD (Crohn's Disease Activity Index [CDAI] score 220-450). Patients were stratified according to C-reactive protein (CRP) levels and corticosteroid use and were randomly assigned to receive placebo or apilimod mesylate 50 mg daily or 100 mg daily. The study was divided into an induction phase (43 days) and a maintenance phase (125 days). The primary analysis involved a comparison of the proportion of patients experiencing clinical response, defined as at least a 100-point decrease in CDAI score from baseline at day 29. Data on adverse events were also collected.

RESULTS

In all, 220 of the planned 282 patients were enrolled when the Data Monitoring Committee determined that the drug was not efficacious as a treatment and closed enrollment. A clinical response was experienced by 18 patients (24.7%) in the 50-mg daily (QD) group (n = 73) and 19 patients (25.7%) in the 100 mg QD group (n = 74), as compared with 21 patients (28.8%) in the placebo group (n = 73) on day 29 (P = 0.71 for each comparison). No significant adverse safety signal was observed.

CONCLUSIONS

Apilimod was well-tolerated but did not demonstrate efficacy over placebo in patients with active CD.

Positive correlation of image analysis by mini-endoscopy with micro-PET scan and histology in rats after esophagoduodenal anastomosis

BACKGROUND

Visual inspection of induced carcinogenic transformation is of crucial interest when evaluating growth patterns and therapeutic effects. In previous studies we have used micro-PET scan to analyze the esophageal adenocarcinoma (EAC) transformation in an intact rat model of esophagoduodenal anastomosis (EDA), in which intestinal metaplasia and EAC were reproduced successfully. Our current study aimed to test the feasibility of evaluating the outcomes of our EDA model with a recently developed mini-endoscope.

METHODS

EDA was performed as described previously. Postoperative rats underwent evaluation with upper endoscopy with the mini-endoscope (±endoscopic biopsy) and a micro-PET scan with (18)F-FDG 3 months after the EDA procedure. Rats were euthanized and the esophagi were collected for histological observation, immunohistochemical staining, and TdT labeling assay. We compared the endoscopic images with the radiographic images of (18)F-FDG uptake by micro-PET scan and correlated the endoscopic images with the histological changes in the EDA rats.

RESULTS

The endoscope provided visualization of the entire esophageal tract and upper stomach, with the smallest detectable lesion being 0.5 mm in diameter. Mini-endoscopy was performed regularly and was tolerated without any significant procedure-related alterations in the esophageal tract. The visualized esophageal lesion correlated well with the micro-PET image and the histological changes in the EDA rats.

CONCLUSIONS

The new mini-endoscope constitutes a practical and reliable tool for diagnosis and regular follow-up of the esophagus in rats. Lesions identified by endoscopic observation were consistent with the changes found in the micro-PET scan, histopathology, and alteration of cellular and molecular events in esophageal mucosa. This instrument will allow for serial endoscopic evaluations, similar to endoscopic screening in humans, which will significantly enhance the preclinical development and evaluation of experimental intravesical antitumor therapies.

Regulated deficit irrigation (RDI) to save water and improve Sauvignon Blanc quality?

With a fast change of land use in Marlborough from extensive pastoral farming to intensive irrigated viticulture, a need has risen to investigate the sustainable use of the available water. In 2001 a 5 ha irrigation research project was installed in a Marlborough Sauvignon Blanc vineyard. Irrigation treatments installed were control (compensate 100% for crop evapotranspiration (ET(O)), 80%, 70% and 60% of ET(O). During the two years that the Regulated Deficit Irrigation (RDI) trial has run so far, very different climatic conditions created much greater differences in yield and vegetative growth, than up to 40% reduction in irrigation, none of which were significant. The use of sap flow in the vines has been fine-tuned and is now giving reliable results on which to base vine water need.

Water and Energy Turnover in a Small Monitor Lizard, Varanus-Acanthurus

The field metabolic rates and water influxes of Varanus acanthurus were determined by means of doubly-labelled water during late spring. The mean metabolic rate was 0.101 +/- 0.032 mL CO2 g-1 h-1, which was equivalent to an energy expenditure of 63 kJ kg-1 day-1 and a fresh food consumption rate of 13.2 g kg-1 day-1. The mean rate of water influx was 15.9 +/- 6.8 mL kg-1 day-1 and it is suggested that up to 30% of water influxes are via pulmo-cutaneous exchange and drinking. It is considered that V. acanthurus is a secretive 'sit and wait' predator and that this accounts for the lower than predicted water influx and metabolic rates of this species.