Vedolizumab and Ustekinumab Levels in Pregnant Women With Inflammatory Bowel Disease and Infants Exposed In Utero.

BACKGROUND & AIMS: Vedolizumab and ustekinumab pharmacokinetics in pregnancy and the infant after in utero exposure remain incompletely defined. We aim to define the antenatal stability of ustekinumab and vedolizumab levels and the time at which infant drug levels become undetectable. METHODS: This multicenter prospective observational cohort study recruited pregnant or preconception women with inflammatory bowel disease receiving vedolizumab or ustekinumab. Trough drug levels, clinical data, and biochemical data were documented preconception, during each trimester of pregnancy, and postpartum. Maternal and cord blood drug levels were measured at delivery and in infants until undetectable. Infant outcomes were assessed until 2 years of age. RESULTS: A total of 102 participants (vedolizumab, n = 58) were included. The majority of mothers were, and remained, in clinical and biochemical remission. Maternal vedolizumab levels decreased over the course of pregnancy in association with increasing weight, rather than increasing gestation. Maternal ustekinumab levels remained stable. The median time to drug becoming undetectable in the infant was shorter for vedolizumab (11 wk; range, 5-19 wk; n = 32) than ustekinumab (14 wk; range, 9-36 wk; n = 17) and correlated positively with infant delivery level. Thirty-two of 41 (88%) and 17 of 30 (67%) vedolizumab- and ustekinumab-exposed infants had undetectable drug levels by 15 weeks of age, respectively. Pregnancy and infant outcomes were favorable. Twenty infants with undetectable drug levels received the rotavirus vaccine, with no adverse reactions reported. CONCLUSIONS: Maternal vedolizumab levels decreased, whereas ustekinumab levels remained stable over the course of pregnancy. Most vedolizumab- and approximately half of ustekinumab-exposed infants had undetectable drug levels by 15 weeks of age. No concerning maternal or infant safety signals were identified.

Fine-mapping inflammatory bowel disease loci to single-variant resolution.

Inflammatory bowel diseases are chronic gastrointestinal inflammatory disorders that affect millions of people worldwide. Genome-wide association studies have identified 200 inflammatory bowel disease-associated loci, but few have been conclusively resolved to specific functional variants. Here we report fine-mapping of 94 inflammatory bowel disease loci using high-density genotyping in 67,852 individuals. We pinpoint 18 associations to a single causal variant with greater than 95% certainty, and an additional 27 associations to a single variant with greater than 50% certainty. These 45 variants are significantly enriched for protein-coding changes (n = 13), direct disruption of transcription-factor binding sites (n = 3), and tissue-specific epigenetic marks (n = 10), with the last category showing enrichment in specific immune cells among associations stronger in Crohn's disease and in gut mucosa among associations stronger in ulcerative colitis. The results of this study suggest that high-resolution fine-mapping in large samples can convert many discoveries from genome-wide association studies into statistically convincing causal variants, providing a powerful substrate for experimental elucidation of disease mechanisms.

Emu Oil Attenuates Disease Severity and Results in Fewer Large Colonic Tumors in a Mouse Model of Colitis-Associated Colorectal Cancer.

Ulcerative colitis patients have an increased risk of developing colorectal cancer (CRC). The aim of the current study was to determine whether Emu Oil (EO) could reduce the severity of colitis, thereby inhibiting colitis-associated CRC (CA-CRC) development. Female C57BL/6 mice (n = 8/group) were injected (i.p.) with saline or azoxymethane (AOM) (7.4 mg/kg). Mice underwent three dextran sulfate sodium (DSS)/water cycles. Mice were orally-administered either water (160 µL) or EO (80 µL or 160 µL) thrice weekly and euthanized after 12 weeks. AOM/DSS decreased bodyweight compared with normal controls (max. 20%; p < 0.05). In AOM/DSS mice, EO (160 µL) increased bodyweight compared with untreated and 80 µL EO-treated mice (max. 10%; p < 0.05). Both volumes of EO reduced disease activity index (DAI) scores on day 49, 56-63 (max. 40%; p < 0.05), compared with AOM/DSS controls. Histological damage was increased in the distal colon of AOM/DSS mice, and reduced by EO (160 µL; p < 0.05). Mucin-secreting goblet cells were increased by AOM/DSS compared to normal, with no effect observed following EO treatment (p > 0.05). Large tumor numbers were decreased in EO-treated mice (160 µL; 2 ± 0.6) compared with AOM/DSS controls (5 ± 0.7; p < 0.05). EO did not impact overall tumor number (p > 0.05). Other analyses remained unchanged across groups (p > 0.05). EO demonstrates promise as an adjunct to conventional treatment options for colitis management.

Level of UV Exposure, Skin Type, and Age Are More Important than Thiopurine Use for Keratinocyte Carcinoma Development in IBD Patients.

BACKGROUND: Retrospective studies observe an increased risk of keratinocyte carcinomas (KCs) in patients with inflammatory bowel disease (IBD) on thiopurine (TP) medication. The role of traditional risk factors such as skin type and sun protection behavior has not been studied in this population. This study aimed to examine traditional KC risk factors and thiopurine use on skin cancer development in an IBD cohort. METHODS: Consecutive IBD patients were recruited from four specialist centers in Australia and New Zealand, each with varying UV exposure indices. Data pertaining to race, skin color, freckling and sun protection behavior, dose of TP therapy, and skin cancer development were elicited through a self-reported questionnaire. RESULTS: A total of 691 IBD patients were included with 62 reporting KC development. Thiopurine usage was similar among patients who developed skin cancer compared with those who did not (92% vs. 89%, p = 0.3). There was no statistically significant association between KC development and TP dose or 6-thioguanine nucleotide levels. In multivariate modeling, four factors were independently and significantly associated with KC: age over 61 years old versus less than 30 years old (OR 6.76; 95% CI 2.38-19.18), residing in Brisbane versus Christchurch (OR 3.3; 95% CI 1.6-6.8), never staying in the shade versus staying in the shade ≥ 50% of the time (OR 3.8; 95% CI 1.4-10.5), and having a skin type that never tanned versus other skin types (OR 6.9; 95% CI 2.9-16.0). CONCLUSION: Skin type, age, and sun protection behavior are more important risk factors for KC development than thiopurine medication use in this IBD population.

Emu Oil reduces disease severity in a mouse model of chronic ulcerative colitis.

Objective: Ulcerative colitis (UC) is characterized by mucosal inflammation and ulceration of the large intestine. Emu Oil (EO) has been reported to protect the intestine against mucositis, NSAID-enteropathy, UC-associated colorectal cancer and acute UC. We aimed to determine whether EO could reduce the severity chronic UC in mice. Methods: Female C57BL/6 mice (n = 10/group) were orally administered (gavage) water (Groups 1-2) or EO (Groups 3: low dose-80 µl and 4: high dose-160 µl), thrice weekly. Group 1 mice consumed plain drinking water throughout the trial. Groups 2-4 mice underwent two cycles [each consisting of seven days dextran sulfate sodium (DSS; 2% w/v) and 14 days water], followed by a third DSS week. All mice were euthanized two days later (day 51). Bodyweight, disease activity index (DAI), burrowing activity, myeloperoxidase activity, crypt depth and histologically assessed damage severity were assessed. p < .05 was considered significant. Results: DSS decreased bodyweight and increased DAI compared to normal controls (p < .05), which was partially attenuated by both EO doses (p < .05). Burrowing activity was impaired in DSS-controls compared to normal controls (days 27 and 40); an effect prevented by both EO doses (p < .05). DSS increased colonic myeloperoxidase activity and crypt depth compared to controls (p < .05), with no significant EO effect. Moreover, DSS increased colonic damage severity compared to normal controls (p < .001). Importantly, both EO doses decreased distal colonic damage severity compared to DSS-controls (p < .001). Conclusions: Emu Oil attenuated clinically- and histologically-assessed disease severity in a mouse model of chronic UC. Emu Oil demonstrates promise as an adjunct to conventional treatment options for UC management.

Emu Oil Improves Clinical Indicators of Disease in a Mouse Model of Colitis-Associated Colorectal Cancer.

BACKGROUND/AIMS: Ulcerative colitis is a remitting and relapsing inflammatory bowel disorder. Current treatments are limited, and if poorly controlled, colitis may progress to colorectal cancer. Previously, Emu Oil protected the intestine in experimental models of gut damage. We aimed to determine whether Emu Oil could reduce the severity of chronic colitis and prevent the onset of neoplasia in a mouse model of colitis-associated colorectal cancer. METHODS: Female C57BL/6 mice were injected (day 0) with azoxymethane, followed by ad libitum access to three dextran sulfate sodium/water cycles (7 days of dextran sulfate sodium and 14 days of water). Mice (n = 9/group) were orally administered either water or Emu Oil (low dose 80 µL or high dose 160 µL), thrice weekly for 9 weeks. Bodyweight and disease activity index were measured daily. Colitis progression was monitored by colonoscopy on days 20, 41 and 62. At killing, tumor number and size were recorded. RESULTS: Azoxymethane/dextran sulfate sodium induced significant bodyweight loss (maximum 24%) which was attenuated by Emu Oil treatment (low dose days 9, 10, 14: maximum 7%; high dose days 7-15, 30-36: maximum 11%; p < 0.05). Emu Oil reduced disease activity index of azoxymethane/dextran sulfate sodium mice at most time points (maximum 20%; p < 0.05). Additionally, Emu Oil reduced colonoscopically assessed colitis severity (days 20 and 62) compared to disease controls (p < 0.05). Finally, in azoxymethane/dextran sulfate sodium mice, low-dose Emu Oil resulted in fewer small colonic tumors (p < 0.05) compared to controls. CONCLUSIONS: Emu Oil improved clinical indicators and reduced severity of colitis-associated colorectal cancer, suggesting therapeutic potential in colitis management.

Inherited determinants of Crohn's disease and ulcerative colitis phenotypes: a genetic association study.

BACKGROUND: Crohn's disease and ulcerative colitis are the two major forms of inflammatory bowel disease; treatment strategies have historically been determined by this binary categorisation. Genetic studies have identified 163 susceptibility loci for inflammatory bowel disease, mostly shared between Crohn's disease and ulcerative colitis. We undertook the largest genotype association study, to date, in widely used clinical subphenotypes of inflammatory bowel disease with the goal of further understanding the biological relations between diseases. METHODS: This study included patients from 49 centres in 16 countries in Europe, North America, and Australasia. We applied the Montreal classification system of inflammatory bowel disease subphenotypes to 34,819 patients (19,713 with Crohn's disease, 14,683 with ulcerative colitis) genotyped on the Immunochip array. We tested for genotype-phenotype associations across 156,154 genetic variants. We generated genetic risk scores by combining information from all known inflammatory bowel disease associations to summarise the total load of genetic risk for a particular phenotype. We used these risk scores to test the hypothesis that colonic Crohn's disease, ileal Crohn's disease, and ulcerative colitis are all genetically distinct from each other, and to attempt to identify patients with a mismatch between clinical diagnosis and genetic risk profile. FINDINGS: After quality control, the primary analysis included 29,838 patients (16,902 with Crohn's disease, 12,597 with ulcerative colitis). Three loci (NOD2, MHC, and MST1 3p21) were associated with subphenotypes of inflammatory bowel disease, mainly disease location (essentially fixed over time; median follow-up of 10·5 years). Little or no genetic association with disease behaviour (which changed dramatically over time) remained after conditioning on disease location and age at onset. The genetic risk score representing all known risk alleles for inflammatory bowel disease showed strong association with disease subphenotype (p=1·65 × 10(-78)), even after exclusion of NOD2, MHC, and 3p21 (p=9·23 × 10(-18)). Predictive models based on the genetic risk score strongly distinguished colonic from ileal Crohn's disease. Our genetic risk score could also identify a small number of patients with discrepant genetic risk profiles who were significantly more likely to have a revised diagnosis after follow-up (p=6·8 × 10(-4)). INTERPRETATION: Our data support a continuum of disorders within inflammatory bowel disease, much better explained by three groups (ileal Crohn's disease, colonic Crohn's disease, and ulcerative colitis) than by Crohn's disease and ulcerative colitis as currently defined. Disease location is an intrinsic aspect of a patient's disease, in part genetically determined, and the major driver to changes in disease behaviour over time. FUNDING: International Inflammatory Bowel Disease Genetics Consortium members funding sources (see Acknowledgments for full list).

Efficacy of Rectal Tacrolimus for Induction Therapy in Patients With Resistant Ulcerative Proctitis.

BACKGROUND & AIMS: Resistant ulcerative proctitis can be extremely difficult to manage. Topically administered tacrolimus, however, may be effective in difficult-to-treat proctitis. This was a randomized, double-blind, placebo-controlled induction trial of rectal tacrolimus in patients with active ulcerative colitis. METHODS: Eleven patients received rectal tacrolimus (0.5 mg/mL), and 10 placebo, for 8 weeks. The primary endpoint was clinical response by using the Mayo Clinic score. RESULTS: A planned interim analysis after 20 patients had completed the study demonstrated highly significant differences between the groups and the study was closed because of ethical considerations with patients already recruited allowed to complete the study. The primary endpoint was met in 8 of 11 patients receiving rectal tacrolimus and 1 of 10 patients receiving placebo (73% vs 10%; P = .004). Of the secondary endpoints, 5 patients with rectal tacrolimus achieved clinical remission compared with none receiving placebo (45% vs 0%; P = .015). Mucosal healing at Week 8 was achieved in 8 patients receiving rectal tacrolimus compared with 1 (73% vs 10%) receiving placebo (P = .004). The Inflammatory Bowel Disease Questionnaire increased ≥16 points over baseline in 5 of the tacrolimus and 2 (45% vs 20%) of the placebo patients (P = .36). Finally, the average partial Mayo score was numerically lower in the tacrolimus-treated group compared with placebo at Week 2 (4.3 ± 0.74 vs 5.8 ± 0.64; P = .15) and Week 4 (3.7 ± 0.96 vs 5.8 ± 0.6; P = .08) but was significantly lower at Week 8 (3.3 ± 1.2 vs 6.7 ± 0.62; P = .01). There were no safety issues identified with rectal tacrolimus use. CONCLUSIONS: Rectal tacrolimus was more effective than placebo for induction of a clinical response, clinical remission, and mucosal healing in resistant ulcerative proctitis (Clinicaltrials.gov registration: NCT01418131).

Concentrations of Adalimumab and Infliximab in Mothers and Newborns, and Effects on Infection.

BACKGROUND & AIMS: Little is known about in utero exposure to and postnatal clearance of anti-tumor necrosis factor (anti-TNF) agents in neonates. We investigated the concentrations of adalimumab and infliximab in umbilical cord blood of newborns and rates of clearance after birth, and how these correlated with drug concentrations in mothers at birth and risk of infection during the first year of life. METHODS: We performed a prospective study of 80 pregnant women with inflammatory bowel diseases at tertiary hospitals in Denmark, Australia, and New Zealand from March 2012 through November 2014: 36 received adalimumab and 44 received infliximab; 39 received concomitant thiopurines during pregnancy. Data were collected from medical records on disease activity and treatment before, during, and after pregnancy. Concentrations of anti-TNF agents were measured in blood samples from women at delivery and in umbilical cords, and in infants for every 3 months until the drug was no longer detected. RESULTS: The time from last exposure to anti-TNF agent during pregnancy correlated inversely with the concentration of the drugs in the umbilical cord (adalimumab: r = -0.64, P = .0003; infliximab: r = -0.77, P < .0001) and in mothers at time of birth (adalimumab, r = -0.80; infliximab, r = -0.80; P < .0001 for both). The median ratio of infant:mother drug concentration at birth was 1.21 for adalimumab (95% confidence interval [CI], 0.94-1.49) and 1.97 for infliximab (95% CI, 1.50-2.43). The mean time to drug clearance in infants was 4.0 months for adalimumab (95% CI, 2.9-5.0) and 7.3 months for infliximab (95% CI, 6.2-8.3; P < .0001). Drugs were not detected in infants after 12 months of age. Bacterial infections developed in 4 infants (5%) and viral infections developed in 16 (20%), all with benign courses. The relative risk for infection was 2.7 in infants whose mothers received the combination of an anti-TNF agent and thiopurine, compared with anti-TNF monotherapy (95% CI, 1.09-6.78; P = .02). CONCLUSIONS: In a prospective study of infants born to mothers who received anti-TNF agents during pregnancy, we detected the drugs until 12 months of age. There was an inverse correlation between the time from last exposure during pregnancy and drug concentration in the umbilical cord. Infliximab was cleared more slowly than adalimumab from the infants. The combination of an anti-TNF agent and thiopurine therapy during pregnancy increased the relative risk for infant infections almost 3-fold compared with anti-TNF monotherapy. Live vaccines therefore should be avoided for up to 1 year unless drug clearance is documented, and pregnant women should be educated on the risks of anti-TNF use.

Performance of risk prediction for inflammatory bowel disease based on genotyping platform and genomic risk score method.

BACKGROUND: Predicting risk of disease from genotypes is being increasingly proposed for a variety of diagnostic and prognostic purposes. Genome-wide association studies (GWAS) have identified a large number of genome-wide significant susceptibility loci for Crohn's disease (CD) and ulcerative colitis (UC), two subtypes of inflammatory bowel disease (IBD). Recent studies have demonstrated that including only loci that are significantly associated with disease in the prediction model has low predictive power and that power can substantially be improved using a polygenic approach. METHODS: We performed a comprehensive analysis of risk prediction models using large case-control cohorts genotyped for 909,763 GWAS SNPs or 123,437 SNPs on the custom designed Immunochip using four prediction methods (polygenic score, best linear genomic prediction, elastic-net regularization and a Bayesian mixture model). We used the area under the curve (AUC) to assess prediction performance for discovery populations with different sample sizes and number of SNPs within cross-validation. RESULTS: On average, the Bayesian mixture approach had the best prediction performance. Using cross-validation we found little differences in prediction performance between GWAS and Immunochip, despite the GWAS array providing a 10 times larger effective genome-wide coverage. The prediction performance using Immunochip is largely due to the power of the initial GWAS for its marker selection and its low cost that enabled larger sample sizes. The predictive ability of the genomic risk score based on Immunochip was replicated in external data, with AUC of 0.75 for CD and 0.70 for UC. CD patients with higher risk scores demonstrated clinical characteristics typically associated with a more severe disease course including ileal location and earlier age at diagnosis. CONCLUSIONS: Our analyses demonstrate that the power of genomic risk prediction for IBD is mainly due to strongly associated SNPs with considerable effect sizes. Additional SNPs that are only tagged by high-density GWAS arrays and low or rare-variants over-represented in the high-density region on the Immunochip contribute little to prediction accuracy. Although a quantitative assessment of IBD risk for an individual is not currently possible, we show sufficient power of genomic risk scores to stratify IBD risk among individuals at diagnosis.

Serologic antibodies in relation to outcome in postoperative Crohn's disease.

BACKGROUND AND AIM: Disease recurs frequently after Crohn's disease resection. The role of serological antimicrobial antibodies in predicting recurrence or as a marker of recurrence has not been well defined. METHODS: A total of 169 patients (523 samples) were prospectively studied, with testing peri-operatively, and 6, 12 and 18 months postoperatively. Colonoscopy was performed at 18 months postoperatively. Serologic antibody presence (perinuclear anti-neutrophil cytoplasmic antibody [pANCA], anti-Saccharomyces cerevisiae antibodies [ASCA] IgA/IgG, anti-OmpC, anti-CBir1, anti-A4-Fla2, anti-Fla-X) and titer were tested. Quartile sum score (range 6-24), logistic regression analysis, and correlation with phenotype, smoking status, and endoscopic outcome were assessed. RESULTS: Patients with ≥ 2 previous resections were more likely to be anti-OmpC positive (94% vs 55%, ≥ 2 vs < 2, P = 0.001). Recurrence at 18 months was associated with anti-Fla-X positivity at baseline (49% vs 29%; positive vs negative, P = 0.033) and 12 months (52% vs 31%, P = 0.04). Patients positive (n = 28) for all four antibacterial antibodies (anti-CBir1, anti-OmpC, anti-A4-Fla2, and anti-Fla-X) at baseline were more likely to experience recurrence at 18 months than patients negative (n = 32) for all four antibodies (82% vs 18%, P = 0.034; odds ratio 6.4, 95% confidence interval 1.16-34.9). The baseline quartile sum score for all six antimicrobial antibodies was higher in patients with severe recurrence (Rutgeert's i3-i4) at 18 months, adjusted for clinical risk factors (odds ratio 1.16, 95% confidence interval 1.01-1.34, P = 0.039). Smoking affected antibody status. CONCLUSIONS: Anti-Fla-X and presence of all anti-bacterial antibodies identifies patients at higher risk of early postoperative Crohn's disease recurrence. Serologic screening pre-operatively may help identify patients at increased risk of recurrence.

Crohn's disease management after intestinal resection: a randomised trial.

BACKGROUND: Most patients with Crohn's disease need an intestinal resection, but a majority will subsequently experience disease recurrence and require further surgery. This study aimed to identify the optimal strategy to prevent postoperative disease recurrence. METHODS: In this randomised trial, consecutive patients from 17 centres in Australia and New Zealand undergoing intestinal resection of all macroscopic Crohn's disease, with an endoscopically accessible anastomosis, received 3 months of metronidazole therapy. Patients at high risk of recurrence also received a thiopurine, or adalimumab if they were intolerant to thiopurines. Patients were randomly assigned to parallel groups: colonoscopy at 6 months (active care) or no colonoscopy (standard care). We used computer-generated block randomisation to allocate patients in each centre to active or standard care in a 2:1 ratio. For endoscopic recurrence (Rutgeerts score ≥i2) at 6 months, patients stepped-up to thiopurine, fortnightly adalimumab with thiopurine, or weekly adalimumab. The primary endpoint was endoscopic recurrence at 18 months. Patients and treating physicians were aware of the patient's study group and treatment, but central reading of the endoscopic findings was undertaken blind to the study group and treatment. Analysis included all patients who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, number NCT00989560. FINDINGS: Between Oct 13, 2009, and Sept 28, 2011, 174 (83% high risk across both active and standard care groups) patients were enrolled and received at least one dose of study drug. Of 122 patients in the active care group, 47 (39%) stepped-up treatment. At 18 months, endoscopic recurrence occurred in 60 (49%) patients in the active care group and 35 (67%) patients in the standard care group (p=0.03). Complete mucosal normality was maintained in 27 (22%) of 122 patients in the active care group versus four (8%) in the standard care group (p=0.03). In the active care arm, of those with 6 months recurrence who stepped up treatment, 18 (38%) of 47 patients were in remission 12 months later; conversely, of those in remission at 6 months who did not change therapy recurrence occurred in 31 (41%) of 75 patients 12 months later. Smoking (odds ratio [OR] 2.4, 95% CI 1.2-4.8, p=0.02) and the presence of two or more clinical risk factors including smoking (OR 2.8, 95% CI 1.01-7.7, p=0.05) increased the risk of endoscopic recurrence. The incidence and type of adverse and severe adverse events did not differ significantly between patients in the active care and standard care groups (100 [82%] of 122 vs 45 [87%] of 52; p=0.51) and (33 [27%] of 122 vs 18 [35%] of 52; p=0.36), respectively. INTERPRETATION: Treatment according to clinical risk of recurrence, with early colonoscopy and treatment step-up for recurrence, is better than conventional drug therapy alone for prevention of postoperative Crohn's disease recurrence. Selective immune suppression, adjusted for early recurrence, rather than routine use, leads to disease control in most patients. Clinical risk factors predict recurrence, but patients at low risk also need monitoring. Early remission does not preclude the need for ongoing monitoring. FUNDING: AbbVie, Gutsy Group, Gandel Philanthropy, Angior Foundation, Crohn's Colitis Australia, and the National Health and Medical Research Council.

Measurement of fecal calprotectin improves monitoring and detection of recurrence of Crohn's disease after surgery.

BACKGROUND & AIMS: Crohn's disease (CD) usually recurs after intestinal resection; postoperative endoscopic monitoring and tailored treatment can reduce the chance of recurrence. We investigated whether monitoring levels of fecal calprotectin (FC) can substitute for endoscopic analysis of the mucosa. METHODS: We analyzed data collected from 135 participants in a prospective, randomized, controlled trial, performed at 17 hospitals in Australia and 1 hospital in New Zealand, that assessed the ability of endoscopic evaluations and step-up treatment to prevent CD recurrence after surgery. Levels of FC, serum levels of C-reactive protein (CRP), and Crohn's disease activity index (CDAI) scores were measured before surgery and then at 6, 12, and 18 months after resection of all macroscopic Crohn's disease. Ileocolonoscopies were performed at 6 months after surgery in 90 patients and at 18 months after surgery in all patients. RESULTS: Levels of FC were measured in 319 samples from 135 patients. The median FC level decreased from 1347 µg/g before surgery to 166 µg/g at 6 months after surgery, but was higher in patients with disease recurrence (based on endoscopic analysis; Rutgeerts score, ≥i2) than in patients in remission (275 vs 72 µg/g, respectively; P < .001). Combined 6- and 18-month levels of FC correlated with the presence (r = 0.42; P < .001) and severity (r = 0.44; P < .001) of CD recurrence, but the CRP level and CDAI score did not. Levels of FC greater than 100 µg/g indicated endoscopic recurrence with 89% sensitivity and 58% specificity, and a negative predictive value (NPV) of 91%; this means that colonoscopy could have been avoided in 47% of patients. Six months after surgery, FC levels less than 51 µg/g in patients in endoscopic remission predicted maintenance of remission (NPV, 79%). In patients with endoscopic recurrence at 6 months who stepped-up treatment, FC levels decreased from 324 µg/g at 6 months to 180 µg/g at 12 months and 109 µg/g at 18 months. CONCLUSIONS: In this analysis of data from a prospective clinical trial, FC measurement has sufficient sensitivity and NPV values to monitor for CD recurrence after intestinal resection. Its predictive value might be used to identify patients most likely to relapse. After treatment for recurrence, the FC level can be used to monitor response to treatment. It predicts which patients will have disease recurrence with greater accuracy than CRP level or CDAI score.

Mechanisms of initiation and progression of intestinal fibrosis in IBD.

Intestinal fibrosis is a common complication of the inflammatory bowel diseases (IBDs). It becomes clinically apparent in >30% of patients with Crohn's disease (CD) and in about 5% with ulcerative colitis (UC). Fibrosis is a consequence of local chronic inflammation and is characterized by excessive extracellular matrix (ECM) protein deposition. ECM is produced by activated myofibroblasts, which are modulated by both, profibrotic and antifibrotic factors. Fibrosis depends on the balance between the production and degradation of ECM proteins. This equilibrium can be impacted by a complex and dynamic interaction between profibrotic and antifibrotic mediators. Despite the major therapeutic advances in the treatment of active inflammation in IBD over the past two decades, the incidence of intestinal strictures in CD has not significantly changed as the current anti-inflammatory therapies neither prevent nor reverse the established fibrosis and strictures. This implies that control of intestinal inflammation does not necessarily affect the associated fibrotic process. The conventional view that intestinal fibrosis is an inevitable and irreversible process in patients with IBD is also gradually changing in light of an improved understanding of the cellular and molecular mechanisms that underline the pathogenesis of fibrosis. Comprehension of the mechanisms of intestinal fibrosis is thus vital and may pave the way for the developments of antifibrotic agents and new therapeutic approaches in IBD.

Prostaglandin E2 and polyenylphosphatidylcholine protect against intestinal fibrosis and regulate myofibroblast function.

BACKGROUND: Intestinal fibrosis is a serious and often recurrent complication of inflammatory bowel disease despite surgical intervention. The anti-fibrotic potential of prostaglandin E2 (PGE2) and polyenylphosphatidylcholine (PC) was investigated using the murine model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced chronic intestinal inflammation and fibrosis, and murine and human intestinal myofibroblasts. METHODS: Mice were treated with TNBS enemas weekly for 2 or 6 weeks ± PGE2 (10 mg/kg/day orally) or PC (200 mg/kg/day orally). Inflammation and fibrosis were histologically assessed and scored. Pro-inflammatory cytokines, TLR4, and ECM-related gene expression from the colonic tissue and cultured myofibroblasts were assessed by RT-qPCR. The levels of α-SMA(+) staining and endogenous PGE2 in vivo were also assessed. RESULTS: Both PGE2 and PC treatment significantly decreased TNBS-induced intestinal inflammation and excess collagen deposition in vivo. This was accompanied by decreased α-SMA(+) staining in the lamina propria and lower collagen type I (COL1α1) expression. Endogenous PGE2 levels demonstrated that PC was not being converted into PGE2, thus mediating its effects primarily via PGE2-independent pathways. Both PGE2 and the PC isoform, 1,2-dilinoleoylphosphatidylcholine (DLPC), regulated primary mouse myofibroblast and CCD-18co COL1α1 production, and induced lower collagen type I to III and TGF-ß1 to TGF-ß3 ratios, demonstrating their ability to induced normal healing in the presence of phorbol 12-myristate 13-acetate (protein kinase C-dependent inducer of collagen production). CONCLUSION: PGE2 and PC both have potent anti-fibrogenic potentials in their ability to regulate inflammatory cell and myofibroblast accumulation within inflamed tissue, to decrease pro-inflammatory cytokine expression and to maintain normal healing in an inflammatory environment.

An Extremes of Phenotype Approach Confirms Significant Genetic Heterogeneity in Patients with Ulcerative Colitis.

BACKGROUND AND AIMS: Ulcerative colitis [UC] is a major form of inflammatory bowel disease globally. Phenotypic heterogeneity is defined by several variables including age of onset and disease extent. The genetics of disease severity remains poorly understood. To further investigate this, we performed a genome wide association [GWA] study using an extremes of phenotype strategy. METHODS: We conducted GWA analyses in 311 patients with medically refractory UC [MRUC], 287 with non-medically refractory UC [non-MRUC] and 583 controls. Odds ratios [ORs] were calculated for known risk variants comparing MRUC and non-MRUC, and controls. RESULTS: MRUC-control analysis had the greatest yield of genome-wide significant single nucleotide polymorphisms [SNPs] [2018], including lead SNP = rs111838972 [OR = 1.82, p = 6.28 × 10-9] near MMEL1 and a locus in the human leukocyte antigen [HLA] region [lead SNP = rs144717024, OR = 12.23, p = 1.7 × 10-19]. ORs for the lead SNPs were significantly higher in MRUC compared to non-MRUC [p < 9.0 × 10-6]. No SNPs reached significance in the non-MRUC-control analysis (top SNP, rs7680780 [OR 2.70, p = 5.56 × 10-8). We replicate findings for rs4151651 in the Complement Factor B [CFB] gene and demonstrate significant changes in CFB gene expression in active UC. Detailed HLA analyses support the strong associations with MHC II genes, particularly HLA-DQA1, HLA-DQB1 and HLA-DRB1 in MRUC. CONCLUSIONS: Our MRUC subgroup replicates multiple known UC risk variants in contrast to non-MRUC and demonstrates significant differences in effect sizes compared to those published. Non-MRUC cases demonstrate lower ORs similar to those published. Additional risk and prognostic loci may be identified by targeted recruitment of individuals with severe disease.

Mesenchymal cell proliferation and programmed cell death: key players in fibrogenesis and new targets for therapeutic intervention.

An exquisite equilibrium between cell proliferation and programmed cell death is required to maintain physiological homeostasis. In inflammatory bowel disease, and especially in Crohn's disease, enhanced proliferation along with defective apoptosis of immune cells are considered key elements of pathogenesis. Despite the relatively limited attention that has been given to research efforts devoted to intestinal fibrosis to date, there is evidence suggesting that enhanced proliferation along with defective programmed cell death of mesenchymal cells can significantly contribute to the development of excessive fibrogenesis in many different tissues. Moreover, some therapies have demonstrated potential antifibrogenic efficacy through the regulation of mesenchymal cell proliferation and programmed cell death. Further understanding of the pathways involved in the regulation of mesenchymal cell proliferation and apoptosis is, however, required.