Gut Microbiome Composition Is Associated With Future Onset of Crohn's Disease in Healthy First-Degree Relatives

BACKGROUND & AIMS

The cause of Crohn's disease (CD) is unknown, but the current hypothesis is that microbial or environmental factors induce gut inflammation in genetically susceptible individuals, leading to chronic intestinal inflammation. Case-control studies of patients with CD have cataloged alterations in the gut microbiome composition; however, these studies fail to distinguish whether the altered gut microbiome composition is associated with initiation of CD or is the result of inflammation or drug treatment.

METHODS

In this prospective cohort study, 3483 healthy first-degree relatives (FDRs) of patients with CD were recruited to identify the gut microbiome composition that precedes the onset of CD and to what extent this composition predicts the risk of developing CD. We applied a machine learning approach to the analysis of the gut microbiome composition (based on 16S ribosomal RNA sequencing) to define a microbial signature that associates with future development of CD. The performance of the model was assessed in an independent validation cohort.

RESULTS

In the validation cohort, the microbiome risk score (MRS) model yielded a hazard ratio of 2.24 (95% confidence interval, 1.03-4.84; P = .04), using the median of the MRS from the discovery cohort as the threshold. The MRS demonstrated a temporal validity by capturing individuals that developed CD up to 5 years before disease onset (area under the curve > 0.65). The 5 most important taxa contributing to the MRS included Ruminococcus torques, Blautia, Colidextribacter, an uncultured genus-level group from Oscillospiraceae, and Roseburia.

CONCLUSION

This study is the first to demonstrate that gut microbiome composition is associated with future onset of CD and suggests that gut microbiome is a contributor in the pathogenesis of CD.

Immune response and barrier dysfunction-related proteomic signatures in preclinical phase of Crohn's disease highlight earliest events of pathogenesis

OBJECTIVE

The measure of serum proteome in the preclinical state of Crohn's disease (CD) may provide insight into biological pathways involved in CD pathogenesis. We aimed to assess associations of serum proteins with future CD onset and with other biomarkers predicting CD risk in a healthy at-risk cohort.

DESIGN

In a nested case-control study within the Crohn's and Colitis Canada Genetics Environment Microbial Project (CCC-GEM) cohort, which prospectively follows healthy first-degree relatives (FDRs), subjects who developed CD (n=71) were matched with four FDRs remaining healthy (n=284). Using samples at recruitment, serum protein profiles using the Olink Proximity Extension Assay platform was assessed for association with future development of CD and with other baseline biomarkers as follows: serum antimicrobial antibodies (AS: positive antibody sum) (Prometheus); faecal calprotectin (FCP); gut barrier function using the fractional excretion of lactulose-to-mannitol ratio (LMR) assay.

RESULTS

We identified 25 of 446 serum proteins significantly associated with future development of CD. C-X-C motif chemokine 9 (CXCL9) had the highest OR with future risk of CD (OR=2.07 per SD, 95% CI 1.58 to 2.73, q=7.9e-5), whereas matrix extracellular phosphoglycoprotein had the lowest OR (OR 0.44, 95% CI 0.29 to 0.66, q=0.02). Notably, CXCL9 was the only analyte significantly associated with all other CD-risk biomarkers with consistent direction of effect (FCP: OR=2.21; LMR: OR=1.67; AS: OR=1.59) (q<0.05 for all).

CONCLUSION

We identified serum proteomic signatures associated with future CD development, reflecting potential early biological processes of immune and barrier dysfunction.

A236 ASSOCIATION OF STOOL METABOLOMIC PROFILE AND MICROBIOME COMPOSITION RISK SCORE WITH FUTURE ONSET OF CROHN’S DISEASE

Background

Microbial composition-based risk score (MRS) was recently developed and validated to predict future risk of developing Crohn’s disease (CD) among healthy first-degree relatives (FDR) of CD patients. We hypothesized that stool metabolomic profiles, some of which are linked to the gut microbiome, are associated with future risk of CD.

Aims

To assess the association of stool metabolomic profile with onset of CD and to determine the correlation between stool metabolites and the MRS

Methods

Healthy FDR of CD patients were recruited as part of the nested case-control cohort of the CCC-GEM Project. Healthy FDRs who later developed CD (n=56) were matched approximately 1:1 by age, sex, follow-up duration, and geographical location with control FDRs remaining healthy (n=66). Stool metabolomics were assessed using the Metabolon’s DiscoveryHD4™ platform, and the stool microbiome characterised by 16s rDNA amplicon sequencing. We fitted a multivariable conditional logistic regression model on the disease status as a function of individual stool metabolites. We additionally performed Spearman correlation between each stool metabolite and the MRS.

Results

Among 1,029 stool metabolites that were analyzed, 79 were associated with future risk of CD (p&lt;0.05); however, none remained significant after multiple testing correction (FDR correction). Considering the exploratory nature of this study with limited sample size, we focused on the top seven metabolites associated with CD onset (p&lt;0.01). Of these, two stool metabolites (dimethylglycine, methylmyristate) were associated with increased risk of CD onset while five (cytosine, guanine, cytidine, hydroxyglutarate, nervonate) were associated with decreased risk of developing CD. The two metabolites positively associated with CD onset were positively correlated with the MRS, while the five metabolites negatively associated with CD onset, were negatively correlated with the MRS. Meanwhile, 24 stool metabolites had significant correlation with MRS (FDR-corrected p&lt;0.2). Among those, a total of four stool metabolites (cytosine, guanine, methymyristate, cytidine) overlapped with the top seven stool metabolites associated with CD onset.

Conclusions

Stool metabolite profiles may predict future risk of CD. A subset of these metabolites have significant correlation with the MRS with consistent direction of effect. This may suggest that stool metabolites mediate the putative effect of the gut microbiome on CD risk. Further validation in the full GEM cohort is warranted.

Funding Agencies

CCC, CIHRThe Leona M. and Harry B. Helmsley Charitable Trust; Kenneth Croitoru is the recipient of the Canada Research Chair in Inflammatory Bowel Diseases; Sun-Ho Lee is a recipient of the Imagine/ CIHR/CAG Fellowship Award; Sun-Ho Lee, Juan Antonio Raygoza Garay, and Williams Turpin are recipients of fellowship awards from the Department of Medicine, Mount Sinai Hospital, Toronto, Canada.

Anti-Microbial Antibody Response is Associated With Future Onset of Crohn's Disease Independent of Biomarkers of Altered Gut Barrier Function, Subclinical Inflammation, and Genetic Risk

BACKGROUND AND AIMS

Altered host immune reactivity to microbial antigens is hypothesized to trigger the onset of Crohn's disease (CD). We aimed to assess whether increased serum anti-microbial antibody response in asymptomatic first-degree relatives (FDRs) of CD patients is an independent risk factor for future CD development.

METHODS

We measured host serum antibody response to 6 microbial antigens at enrollment (Prometheus enzyme-linked immunosorbent assay test: anti-Saccharomyces cerevisiae antibodies immunoglobulin A/immunoglobulin G, anti-OmpC, anti-A4-Fla2, anti-FlaX, anti-CBir1) and derived the sum of positive antibodies (AS). We used samples at enrollment of prospectively followed healthy FDRs from a nested case-control cohort of the Crohn's and Colitis Canada Genetics Environment Microbial Project. Those who later developed CD (n = 77) were matched 1:4 by age, sex, follow-up duration, and geographic location with control FDRs remaining healthy (n = 307). To address our research aims, we fitted a multivariable conditional logistic regression model and performed causal mediation analysis.

RESULTS

High baseline AS (≥2) (43% of cases, 11% of controls) was associated with higher risk of developing CD (adjusted odds ratio, 6.5; 95% confidence interval, 3.4-12.7; P < .001). Importantly, this association remained significant when adjusted for markers of gut barrier function, fecal calprotectin, C-reactive protein, and CD-polygenic risk score, and in subjects recruited more than 3 years before diagnosis. Causal mediation analysis showed that the effect of high AS on future CD development is partially mediated (42%) via preclinical gut inflammation.

CONCLUSIONS

Our results suggest that increased anti-microbial antibody responses are associated with risk of future development of CD, independent of biomarkers of abnormal gut barrier function, subclinical inflammation, and CD-related genetic risks. This suggests that anti-microbial antibody responses are an early predisease event in the development of CD.

A198 LEFLUNOMIDE-INDUCED COLITIS IN IMMUNOSUPPRESSED PATIENT WITH SYSTEMIC LUPUS ERYTHEMATOSUS AND RHEUMATOID ARTHRITIS

Background

Leflunomide is an oral disease-modifying antirheumatic drug (DMARD), with anti-inflammatory and immunomodulatory properties that has been in use since 1998. Common leflunomide side-effects include gastrointestinal symptoms (nausea, abdominal pain and diarrhea), occurring in 10–20% of patients treated with leflunomide. Scarce evidence exists that leflunomide can cause colitis.

Aims

We present the case of a 61-year-old female, with Lupus Erythematosus who presented with colitis induced by long-term leflunomide treatment.

Methods

Case report and review of literature

Results

A 61-year-old female was seen by the gastroenterology team with complaints of diarrhea ongoing for 6 weeks associated with 10 lb weight loss. The patient had a complex medical history, including lupus, hypothyroidism, asthma, atrial fibrillation, recurrent C. difficile infection, Bell’s palsy and avascular necrosis secondary to long-term corticosteroid therapy. Previous immunosuppressive therapies included prednisone, mycophenolic acid (Myfortic), hydroxychloroquine, azathioprine, mycophenolate (CellCept) but due to multiple intolerances, she was initiated on leflunomide in 2014 and has been maintained on it since.

Stool analysis ruled out infectious causes. COVID-19 testing was also negative. A CT of the abdomen revealed pancolitis. This was confirmed on colonoscopy, which revealed mild, Mayo 1 pancolitis and normal terminal ileum. She was initiated on Mezavant as a treatment for possible ulcerative colitis. However, during the hospitalization her symptoms, worsened and bloody diarrhea was noted. She underwent a subsequent endoscopic evaluation which revealed more severe disease, Mayo 2–3 colitis, with mucosal hyperemia and ulcerations, as well as effacement of the vasculature. Initial pathology results revealed mild colitis, but repeat pathology results revealed moderate active colitis, with cryptitis, crypt abscesses and significant apoptosis consistent with drug-induced colitis. Given these findings, the diagnosis of leflunomide-induced colitis was made. Leflunomide was therefore discontinued, the patient was initiated on a higher dose of corticosteroids and cholestyramine was initiated. Following these measures, her diarrhea resolved.

Conclusions

Leflunomide may cause diarrhea in up to 33% of patients. Challenges related to the diagnosis of leflunomide-induced colitis exist, including the rarity of the diagnosis, a not completely understood mechanism for acute leflunomide-induced diarrhea, as well as variable endoscopic and histologic findings associated with the diagnosis. This report illustrates a case of leflunomide-induced colitis which should be considered in patients on leflunomide, who present with symptoms of abdominal pain and diarrhea, even years after medication initiation.

Funding Agencies

None

Screening and Treatment Outcomes in Adults and Children With Type 1 Diabetes and Asymptomatic Celiac Disease: The CD-DIET Study

OBJECTIVE

To describe celiac disease (CD) screening rates and glycemic outcomes of a gluten-free diet (GFD) in patients with type 1 diabetes who are asymptomatic for CD.

RESEARCH DESIGN AND METHODS

Asymptomatic patients (8-45 years) were screened for CD. Biopsy-confirmed CD participants were randomized to GFD or gluten-containing diet (GCD) to assess changes in HbA_1c and continuous glucose monitoring over 12 months.

RESULTS

Adults had higher CD-seropositivity rates than children (6.8% [95% CI 4.9-8.2%, N = 1,298] vs. 4.7% [95% CI 3.4-5.9%, N = 1,089], P = 0.035) with lower rates of prior CD screening (6.9% vs. 44.2%, P < 0.0001). Fifty-one participants were randomized to a GFD (N = 27) or GCD (N = 24). No HbA_1c differences were seen between the groups (+0.14%, 1.5 mmol/mol; 95% CI -0.79 to 1.08; P = 0.76), although greater postprandial glucose increases (4-h +1.5 mmol/L; 95% CI 0.4-2.7; P = 0.014) emerged with a GFD.

CONCLUSIONS

CD is frequently observed in asymptomatic patients with type 1 diabetes, and clinical vigilance is warranted with initiation of a GFD.

A112 ANGIOEDEMA,A RARE YET AN IMPORTANT CAUSE OF ABDOMINAL PAIN. A CASE STUDY AND LITERATURE REVIEW

Background

Abdominal pain is a common gastroenterological symptom with an extensive deferential diagnoses. Angioedema is an important cause to remember after the more common causes have been excluded.It is caused by a deficiency in the inhibitor of the first component of classical complement pathway and is divided into hereditary or acquired.Acquired angioedema is associated with autoimmune or lymphoproliferative neoplasms.The clinical features of both include recurrent,self-limiting and circumscribed edema affecting the subcutaneous tissue of the upper respiratory airways and gastrointestinal tract.

Aims

We describe an interesting case of acquired angioedema presenting with recurrent abdominal pain. We also systematically review the current literature on this rare entity.

Methods

A search of electronic databases was performed inclusive to September 2019, for all studies and reviews of patients with acquired angioedema manifested as recurrent attacks of abdominal pain.

Results:

Case Report: 65 year old lady ho has an at least 2 year long history of abdominal pain and bloating associated on some occasions with nausea and vomiting.She presented to our emergency department in August,2018 with a day history of severe generalized abdominal pain and was found to have circumferential thickening,edema with mucosal hyperenhancement involving the distal segment of the small bowel.Splenomegaly was noted on that study.A double balloon enteroscopy was planned,but ultimately cancelled as her ileitis had resolved.The patient was discharged home as her pain resolved with conservative management which included intravenous fluid, pain medications and antiemetics.She then represented to the hospital on September 16, 2019 severe abdominal pain and throat tightness associated with shortness of breath. Again,noted was an extremely short segment of ileum with mucosal edema and hyperenhancement which resolved on a repeat CT scan done during that admission on September 18th, 2019.In light of the patient’s symptoms,CT scan findings,progressive anemia, thrombocytopenia and splenomegaly. It was thought that her abdominal pain is related to secondary to angioedema driven by a lymphoproliferative process as evident by the splenomegaly and worsening cytopenia. A bone marrow was done which revealed clonal B, so the diagnosis of lymphoma was made. The patient’s C1 esterase was 0.2 with reduced functional activity.CH50 less 10 perecent. A diagnosis of acquired angioedema was made and the patient was started on BERINERT 3000 IU SQ every three days with 1500 IU for break through with significant improvement in the frequency and severity of abdominal pain episodes.

Conclusions

Acquired angioedema is to be considered as a cause of recurrent abdominal pain in a patient with a lymphoproliferative malignancy after common causes and etiologies have been ruled out.

Funding Agencies

None

Adult-onset autoimmune-type enteropathy: potential relationship to an adverse drug reaction

Objective

To describe an example of adult-onset autoimmune enteropathy (AIE) that coincided with drug-induced reaction.

Design

A 54-year-old patient was presented with Stevens-Johnson syndrome after a course of quinolones. This was followed shortly thereafter by epigastric pain, diarrhoea and weight loss. She also developed an autoimmune neutropenia.

Results

Several biopsies were performed from the upper and lower gastrointestinal tract (GIT). The duodenal biopsies showed intraepithelial lymphocytosis; therefore, coeliac disease was considered. However, confirmatory serology was negative and the patient did not respond to a gluten-free/gliadin-free diet. Both upper and lower GIT biopsies consistently showed an absence of goblet cells resembling the changes of an AIE.

Conclusion

This is an unusual case of autoimmune-pattern enteropathy in an adult that was potentially drug-induced.

Analysis of Genetic Association of Intestinal Permeability in Healthy First-degree Relatives of Patients with Crohn's Disease

Excessive intestinal permeability or intestinal barrier dysfunction as measured by various assays has been observed in various diseases. However, little is known about the factors contributing to altered gut permeability in these diseases. Our objective was to determine the genetic determinants of altered gut permeability as measured by the lactulose mannitol fractional excretion ratio (LacMan ratio) in 1075 healthy first-degree relatives of patients with Crohn's disease (CD). In a targeted analysis of single nucleotide polymorphisms (SNPs) located in genes associated with intestinal barrier function related or not to inflammatory bowel disease, we did not find a significant association with intestinal permeability. In an untargeted genome-wide association analysis, the top 100 associations were located in 22 genomic loci, although they were not statistically significant after correction for multiple testing (raw P values [1.8 × 10-7 - 1.4 × 10-5]. The lowest P value was obtained for rs9616637 (22q13.33, C22orf34), for which the minor allele A was associated with a decreased LacMan ratio. These results suggest that host genetic background has limited contribution toward intestinal permeability. Despite this, our study is currently the largest of its kind assessing gut permeability in vivo. It remains possible that smaller genetic effect sizes on LacMan ratio are not detectable in this sized cohort. Larger studies are warranted to identify the potential genetic contribution to intestinal permeability.

Progressive learning in endoscopy simulation training improves clinical performance: a blinded randomized trial

BACKGROUND AND AIMS

A structured comprehensive curriculum (SCC) that uses simulation-based training (SBT) can improve clinical colonoscopy performance. This curriculum may be enhanced through the application of progressive learning, a training strategy centered on incrementally challenging learners. We aimed to determine whether a progressive learning-based curriculum (PLC) would lead to superior clinical performance compared with an SCC.

METHODS

This was a single-blinded randomized controlled trial conducted at a single academic center. Thirty-seven novice endoscopists were recruited and randomized to either a PLC (n = 18) or to an SCC (n = 19). The PLC comprised 6 hours of SBT, which progressed in complexity and difficulty. The SCC included 6 hours of SBT, with cases of random order of difficulty. Both groups received expert feedback and 4 hours of didactic teaching. Participants were assessed at baseline, immediately after training, and 4 to 6 weeks after training. The primary outcome was participants' performance during their first 2 clinical colonoscopies, as assessed by using the Joint Advisory Group Direct Observation of Procedural Skills assessment tool (JAG DOPS). Secondary outcomes were differences in endoscopic knowledge, technical and communication skills, and global performance in the simulated setting.

RESULTS

The PLC group outperformed the SCC group during first and second clinical colonoscopies, measured by JAG DOPS (P < .001). Additionally, the PLC group had superior technical and communication skills and global performance in the simulated setting (P < .05). There were no differences between groups in endoscopic knowledge (P > .05).

CONCLUSIONS

Our findings demonstrate the superiority of a PLC for endoscopic simulation, compared with an SCC. Challenging trainees progressively is a simple, theory-based approach to simulation whereby the performance of clinical colonoscopies can be improved. (Clinical trial registration number: NCT02000180.).

High prevalence of adenomatous colorectal polyps in young cancer survivors treated with abdominal radiation therapy: results of a prospective trial

OBJECTIVE

Cancer survivors treated with abdominal/pelvic radiation therapy (ART) have increased the risks of colorectal cancer (CRC), although evidence supporting early CRC screening for these patients is lacking. We sought to determine whether there is an elevated prevalence of adenomatous colorectal polyps in young survivors prior to the age when screening would be routinely recommended.

DESIGN

We conducted a prospective study of early colonoscopic screening in cancer survivors aged 35-49 who had received ART ≥10 years previously. The planned sample size was based on prior studies reporting a prevalence of adenomatous polyps of approximately 20% among the average-risk population ≥50 years of age, in contrast to ≤10% among those average-risk people aged 40-50 years, for whom screening is not routinely recommended.

RESULTS

Colonoscopy was performed in 54 survivors, at a median age of 45 years (range 36-49) and after median interval from radiation treatment of 19 years (10.6-43.5). Forty-nine polyps were detected in 24 patients, with 15 patients (27.8%; 95% CI 17.6% to 40.9%) having potentially precancerous polyps. Fifty-three per cent of polyps were within or at the edge of the prior ART fields.

CONCLUSIONS

Young survivors treated with ART have a polyp prevalence comparable with the average-risk population aged ≥50 years and substantially higher than previously reported for the average-risk population aged 40-50 years. These findings lend support to the early initiation of screening in these survivors.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00982059; results.

Impact of a simulation training curriculum on technical and nontechnical skills in colonoscopy: a randomized trial

BACKGROUND

GI endoscopy simulation-based training augments early clinical performance; however, the optimal manner by which to deliver training is unknown.

OBJECTIVE

We aimed to validate a simulation-based structured comprehensive curriculum (SCC) designed to teach technical, cognitive, and integrative competencies in colonoscopy.

DESIGN

Single-blinded, randomized, controlled trial.

SETTING

Endoscopic simulation course at an academic hospital.

PARTICIPANTS AND INTERVENTIONS

Thirty-three novice endoscopists were allocated to an SCC group or self-regulated learning (SRL) group. The SCC group received a curriculum consisting of 6 hours of didactic lectures and 8 hours of virtual reality simulation-based training with expert feedback. The SRL group was provided a list of desired objectives and was instructed to practice on the simulator for an equivalent time (8 hours).

MAIN OUTCOME MEASUREMENTS

Clinical transfer was assessed during 2 patient colonoscopies using the Joint Advisory Group Direct Observation of Procedural Skills (JAG DOPS) scale. Secondary outcome measures included differences in procedural knowledge, immediate post-training simulation performance, and delayed post-training (4-6 weeks) performance during an integrated scenario test on the JAG DOPS communication and integrated scenario global rating scales.

RESULTS

There was no significant difference in baseline or post-training performance on the simulator task. The SCC group performed superiorly during their first and second clinical colonoscopies. Additionally, the SCC group demonstrated significantly better knowledge and colonoscopy-specific performance, communication, and global performance during the integrated scenario.

LIMITATIONS

We were unable to measure SRL participants' effort outside of mandatory training. In addition, feedback metrics and number of available simulation cases are limited.

CONCLUSIONS

These results support integration of endoscopy simulation into a structured curriculum incorporating instructional feedback and complementary didactic knowledge as a means to augment technical, cognitive, and integrative skills acquisition, as compared with SRL on virtual reality simulators. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT01991522.)

The Celiac Disease and Diabetes-Dietary Intervention and Evaluation Trial (CD-DIET) protocol: a randomised controlled study to evaluate treatment of asymptomatic coeliac disease in type 1 diabetes

INTRODUCTION

Coeliac disease (CD) is an autoimmune condition characterised by gluten-induced intestinal inflammation, and observed at a 5-10 fold greater prevalence in type 1 diabetes. While universal screening for CD in patients with diabetes is frequently advocated, objective data is limited as to benefits on diabetes control, bone health or quality of life related to the adoption of a gluten-free diet (GFD) in the large proportion of patients with diabetes with asymptomatic CD. The Celiac Disease and Diabetes-Dietary Intervention and Evaluation Trial (CD-DIET) study is a multicenter, randomised controlled trial to evaluate the efficacy and safety of a GFD in patients with type 1 diabetes with asymptomatic CD.

METHODS AND ANALYSIS

Children and adults (8-45 years) with type 1 diabetes will be screened for asymptomatic CD. Eligible patients with biopsy-proven CD will be randomly assigned in a 1:1 ratio to treatment with a GFD for 1 year, or continue with a gluten-containing diet. The primary outcome will evaluate the impact of the GFD on change in glycated haemoglobin. Secondary outcomes will evaluate changes in bone mineral density, blood glucose variability and health-related quality of life between GFD-treated and the regular diet group over a 1-year period. The study was initiated in 2012 and has subsequently expanded to multiple paediatric and adult centres in Ontario, Canada.

ETHICS AND DISSEMINATION

The findings from this study will provide high-quality evidence as to the impact of GFD treatment on glycaemic control and complications in asymptomatic children and adults with CD and type 1 diabetes.

TRIAL REGISTRATION NUMBER

NCT01566110.

The phenotypic expression of inflammatory bowel disease in patients with primary sclerosing cholangitis differs in the distribution of colitis

BACKGROUND

Inflammatory bowel disease (IBD) associated with primary sclerosing cholangitis (PSC) is reported to be mild and prone to right-side predominance with rectal sparing. However, no dedicated studies evaluating patterns of presentation of liver disease with respect to IBD are available.

METHODS

We performed a detailed histological examination of the colonic biopsies in the context of PSC, identifying 97 patients [89 with ulcerative colitis and ten with Crohn's disease (CD)] stratified into two groups, based on their initial disease presentation: hepatic/biliary (group 1-PSC-IBD; n=56) versus colonic (group 2-IBD-PSC; n=41).

RESULTS

Inflammatory bowel disease that preceded PSC had a tendency to have a "pan-colitis" distribution; this group included all patients with CD. Inflammatory bowel disease diagnosis that followed PSC presentation was more likely to be right-sided, sparing the descending, sigmoid and rectal regions (p=0.002). In both groups, colitis was mild with focal deep plasmacytosis and occasional mild cryptitis. Active cryptitis with crypt abscesses, surface erosion and ulceration were not identified in any of the patients.

CONCLUSION

Colitis associated with PSC shows mild disease activity and the colitis pattern is associated with disease presentation, i.e. colitis preceding PSC (IBD-PSC cohort) typically have a pancolitic distribution, while colitis following PSC (PSC-IBD cohort) demonstrates right-sided predominance. Awareness by pathologists and clinicians of these patterns of inflammatory bowel disease is important and of use in directing appropriate investigations for patients.

Bone mineral density in Crohn's disease: a longitudinal study of budesonide, prednisone, and nonsteroid therapy

OBJECTIVE

Corticosteroids may contribute to the bone loss associated with Crohn's disease (CD). We investigated the effect on bone mineral density (BMD) of treatment with budesonide, a steroid with low systemic activity, and compared the outcome with prednisone and nonsteroid therapy in patients with CD.

METHODS

Prospective annual BMDs of the lumbar spine (LS) and femoral neck (FN) were measured for 2 yr in 138 patients with quiescent CD treated with mean daily doses of 8.5 mg of budesonide (n = 48), 10.5 mg of prednisone (n = 45), or nonsteroid drugs (n = 45).

RESULTS

Between baseline and 1 yr, the mean LS BMD decreased 2.36% in the budesonide group (p < 0.001), 0.61% in the prednisone group (ns), and 0.09% in the nonsteroid group (ns). The difference between budesonide and nonsteroid groups was significant (p = 0.003). In the 2nd yr, LS BMD did not change in the three groups. After 2 yr, FN BMD decreased 2.94% in the budesonide group (p < 0.01), 0.36% in the prednisone group (ns), and 1.05% in the nonsteroid group (ns); the differences among groups were not significant. The proportion of patients with bone loss of >2% per annum at the LS and FN was higher in the budesonide group than in the nonsteroid group (p < 0.001) and prednisone group (p < 0.05).

CONCLUSIONS

Patients with CD receiving maintenance treatment for 2 yr with prednisone show little change in BMD, whereas treatment with budesonide may be associated with LS and FN bone loss. Budesonide does not confer an advantage over low-dose prednisone for the preservation of BMD.

Circulating levels of glucagon-like peptide-2 in human subjects with inflammatory bowel disease

Glucagon-like peptide-2 (GLP-2) is a recently characterized intestine-derived peptide that exerts trophic activity in the small and large intestine. Whether circulating levels of GLP-2 are perturbed in the setting of human inflammatory bowel disease (IBD) remains unknown. The circulating levels of bioactive GLP-2-(1-33) compared with its degradation product GLP-2-(3-33) were assessed using a combination of RIA and HPLC in normal and immunocompromised control human subjects and patients hospitalized for IBD. The activity of the enzyme dipeptidyl peptidase IV (DP IV), a key determinant of GLP-2-(1-33) degradation was also assessed in the plasma of normal controls and subjects with IBD. The circulating levels of bioactive GLP-2-(1-33) were increased in patients with either ulcerative colitis (UC) or Crohn's Disease (CD; to 229 +/- 65 and 317 +/- 89%, P < 0.05, of normal, respectively). Furthermore, the proportion of total immunoreactivity represented by intact GLP-2-(1-33), compared with GLP-2-(3-33), was increased from 43 +/- 3% in normal healthy controls to 61 +/- 6% (P < 0.01) and 59 +/- 2% (P < 0.01) in patients with UC and CD, respectively. The relative activity of plasma DP IV was significantly reduced in subjects with IBD compared with normal subjects (1.4 +/- 0.3 vs. 5.0 +/- 1.1 mU/ml, respectively; P < 0.05). These results suggest that patients with active IBD may undergo an adaptive response to intestinal injury by increasing the circulating levels of bioactive GLP-2-(1-33), facilitating enhanced repair of the intestinal mucosal epithelium in vivo.

Generation of hydrogen peroxide by brain mitochondria: the effect of reoxygenation following postdecapitative ischemia

The hypothesis that mitochondria damaged during complete cerebral ischemia generate increased amounts of superoxide anion radical and hydrogen peroxide (H2O2) upon postischemic reoxygenation has been tested. In rat brain mitochondria, succinate supported H2O2 generation, whereas NADH-linked substrates, malate plus glutamate, did so only in the presence of respiratory chain inhibitors. Succinate-supported H2O2 generation was diminished by rotenone and the uncoupler carbonyl cyanide m-chlorphenylhydrazone and enhanced by antimycin A and increased oxygen tensions. When maximally reduced, the NADH dehydrogenase and the ubiquinone-cytochrome b regions of the electron transport chain are sources of H2O2. These studies suggest that a significant portion of H2O2 generation in brain mitochondria proceeds via the transfer of reducing equivalents from ubiquinone to the NADH dehydrogenase portion of the electron transport chain. Succinate-supported H2O2 generation by mitochondria isolated from rat brain exposed to 15 min of postdecapitative ischemia was 90% lower than that of control preparations. The effect of varying oxygen tensions on H2O2 generation by postischemic mitochondrial preparations was negligible compared with the increased H2O2 generation measured in control preparations. Comparison of the effects of respiratory chain inhibitors and oxygen tension on succinate-supported H2O2 generation suggests that the ability for reversed electron transfer is impaired during ischemia. These data do not support the hypothesis that mitochondrial free radical generation increases during postischemic reoxygenation.