A contemporary and critical appraisal of 'indeterminate colitis'

Thrombospondin 2, matrix Gla protein and digital analysis identified distinct fibroblast populations in fibrostenosing Crohn's disease

Fibrosis is an important complication in inflammatory bowel diseases. Previous studies suggest an important role of matrix Gla protein (MGP) and thrombospondin 2 (THBS2) in fibrosis in various organs. Our aim was to analyse their expression together with regulatory miRNAs in submucosal and subserosal fibroblasts in ulcerative colitis (UC) and Crohn's disease (CD) using immunohistochemistry and qPCR. Digital pathology was used to compare collagen fibre characteristics of submucosal and subserosal fibrosis. Immunohistochemistry showed expression of MGP, but not THBS2 in submucosa in UC and CD. In the subserosa, there was strong staining for both proteins in CD but not in UC. qPCR showed significant upregulation of THBS2 and MGP genes in CD subserosa compared to the submucosa. Digital pathology analysis revealed higher proportion of larger and thicker fibres that were more tortuous and reticulated in subserosal fibrosis compared to submucosal fibrosis. These results suggest distinct fibroblast populations in fibrostenosing CD, and are further supported by image analysis showing significant differences in the morphology and architecture of collagen fibres in submucosal fibrosis in comparison to subserosal fibrosis. Our study is the first to describe differences in submucosal and subserosal fibroblast populations, contributing to understanding of the pathogenesis of fibrostenosis in CD.

Interplay of broccoli/broccoli sprout bioactives with gut microbiota in reducing inflammation in inflammatory bowel diseases

Inflammatory Bowel Diseases (IBD) are chronic, reoccurring, and debilitating conditions characterized by inflammation in the gastrointestinal tract, some of which can lead to more systemic complications and can include autoimmune dysfunction, a change in the taxonomic and functional structure of microbial communities in the gut, and complicated burdens in a person's daily life. Like many diseases based in chronic inflammation, research on IBD has pointed towards a multifactorial origin involving factors of the person's lifestyle, immune system, associated microbial communities, and environmental conditions. Treatment currently exists only as palliative care, and seeks to disrupt the feedback loop of symptoms by reducing inflammation and allowing as much of a return to homeostasis as possible. Various anti-inflammatory options have been explored, and this review focuses on the use of diet as an alternative means of improving gut health. Specifically, we highlight the connection between the role of sulforaphane from cruciferous vegetables in regulating inflammation and in modifying microbial communities, and to break down the role they play in IBD.

Risk of incisional hernia repair in patients with inflammatory bowel disease

AIM

Patients with inflammatory bowel disease (IBD) may undergo several abdominal surgeries with a risk of incisional hernia repair (IHR). The objectives of this study were to establish the risk of IHR and to analyse predictors of IHR after a first-time abdominal surgery for IBD.

METHOD

This Danish nationwide register-based cohort study (1996-2018) followed IBD patients from index operation until the date of IHR. The absolute risk was calculated as the cumulative incidence proportion treating death as a competing risk. Cox proportional hazard regression was used to compare the risk of IHR among different subtypes of IBD and to explore predictors of IHR. IBD subtypes were classified as ulcerative colitis (UC), Crohn's disease (CD) or unclassified IBD (IBD-U).

RESULTS

In total, 10 130 patients with IBD (UC 3911 [39%]; CD 4210 [41%]; IBD-U 2009 [20%]) underwent either an open or a laparoscopic index operation. The 10-year cumulative incidence of IHR varied between 5.0% and 6.3%, with a significantly higher risk in patients with UC and IBD-U. Patients with UC (75.9%) and IBD-U (91.9%) had more (two or more) abdominal surgeries in the follow-up period compared with CD (51.9%). The risk of IHR increased dramatically with the number of surgeries, although not as markedly if a laparoscopic approach was used. Male sex, age, comorbidity, fascial dehiscence, wound infection and presence of stoma were predictors of IHR for patients with IBD.

CONCLUSION

The long-term risk of IHR was roughly 5%-6%, with a higher risk in patients with UC and IBD-U. Open surgical approach and number of previous surgeries were, among other things, important predictors of IHR.

Racial or ethnic differences on treatment adherence and persistence among patients with inflammatory bowel diseases initiated with biologic therapies

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic disease with the potential for significant morbidity in case of suboptimal treatment (e.g. low treatment adherence). In spite of immense research in IBD, literature on association of IBD with race/ethnicity is fragmented. In this study, we aimed to evaluate the association between race/ethnicity and treatment adherence and persistence among patients with Crohn's disease (CD) or ulcerative colitis (UC) initiated with biologic therapies.

METHODS

This observational, retrospective study utilized the Optum Clinformatics (Optum) Extended Data Mart Socioeconomic Status (SES) database. Adult patients with ≥ 2 medical claims for CD or UC diagnosis, ≥ 1 medical or pharmacy claim for corresponding FDA-approved biologic therapy, and a ≥ 12-month pre-index (index date: date of the first biologic medical/pharmacy claim) continuous health plan enrollment were included. Treatment adherence was measured as the proportion of days covered of ≥ 80% and treatment persistence by the number of days from the index date to the biologics discontinuation date. Switching among biologics was allowed for both treatment adherence and treatment persistence. Multivariable regression analyses were performed to evaluate the association between race/ethnicity and treatment adherence/persistence.

RESULTS

Among patients with CD (N = 1430) and UC (N = 1059) included, majority were White (CD: 80.3%, UC: 78.3%), followed by African Americans (AA; CD: 10.5%, UC: 9.7%). Among patients with CD, AA were significantly less likely to adhere to biologics (adjusted OR [95%CI]: 0.61 [0.38; 0.99]) and more likely to discontinue biologics earlier (adjusted HR [95%CI]: 1.52 [1.16; 2.0]) during the follow-up period compared to Whites, after adjusting for other patient sociodemographic and clinical characteristics. Among patients with UC, no significant differences in the treatment adherence/persistence were observed between different races/ethnicities.

CONCLUSIONS

Patients with CD were found to display racial differences in the treatment adherence and persistence of biologics, with significantly lower adherence and earlier discontinuation in AA compared to Whites. Such differences were not observed in patients with UC. Future studies are warranted to understand the possible reasons for racial differences, particularly in patients with CD.

Crohn's of the Pouch: Now What?

Total proctocolectomy and ileal pouch anal anastomosis (IPAA) is the gold standard surgical treatment for the majority (∼90%) of ulcerative colitis (UC) patients. In cases of carefully selected Crohn's colitis patients without small bowel or perianal involvement an "intentional IPAA" may be a viable option for disease resection and restoration of intestinal continuity. More commonly, Crohn's is incidentally found either in the resection specimen or, more commonly, when inflammatory complications subsequently arise after pouch construction for UC or indeterminate colitis. These incidental Crohn's pouches may be diagnosed early or late period post-IPAA. Crohn's may manifest within the pouch, in the proximal small bowel, and/or distally in the rectal cuff or anus. Like intestinal Crohn's, Crohn's disease of the pouch may be of an inflammatory, fibrostenosing, or fistulizing phenotype. Treatment depends on the phenotype and includes medical treatment, most commonly in the form of tumor necrosis factor inhibitor medications; however, the newer small molecules offer a potential treatment for these patients. Surgery first entails treating the sequelae of Crohn's and is typically staged. In up to 60% of Crohn's pouches, particularly in fistulizing disease and/or recalcitrant perianal disease, the pouch fails and must be defunctioned or excised. In patients with Crohn's pouches in situ long term, outcomes including quality of life are comparable to patients who underwent IPAA for UC.

Temporal changes in the histology of microscopic colitis

BACKGROUND

In a subgroup of patients with microscopic colitis [MC], its histopathology changed from lymphocytic [LC] to collagenous colitis [CC] and vice versa. Previous studies have also observed histopathological transitions between MC and inflammatory bowel disease [IBD].

AIMS

The aim of the present study was to analyse the prevalence of such transitions in a large population of MC patients.

METHODS

The Inform Diagnostics database is an electronic repository of histopathology records of patients distributed throughout the USA. In a cross-sectional study, we analysed the prevalence of changes in MC histology. Each prevalence was expressed as the rate per 100 MC patients with its 95% Poisson confidence interval.

RESULTS

In a total population of 29 307 MC patients, our cross-sectional study focused on a subgroup of 4363 patients who underwent two or more consecutive colonoscopies between December 2008 and March 2020. Overall, 1.6% [95% CI 1.2-2.0%] of patients changed their MC phenotype from LC to CC, and 0.5% [0.3-0.7%] from CC to LC. Of 4363 MC patients, 414 [9.5%] were also diagnosed with IBD. In 2.9% [2.4-3.5%], MC and IBD were diagnosed as synchronous mucosal lesions. In 2.1% [1.7-2.6%], MC changed to IBD, and in 4.5% [3.9-5.2%] IBD changed to MC.

CONCLUSIONS

The analysis confirmed the synchronous occurrence of MC and IBD and transitions between the two diagnoses. In patients who fail therapy for either one of the two diseases, the gastroenterologist should search for changes in the underlying phenotype as a possible explanation.

ECCO Topical Review Optimising Reporting in Surgery, Endoscopy, and Histopathology

BACKGROUND AND AIMS

Diagnosis and management of inflammatory bowel diseases [IBD] requires a lifelong multidisciplinary approach. The quality of medical reporting is crucial in this context. The present topical review addresses the need for optimised reporting in endoscopy, surgery, and histopathology.

METHODS

A consensus expert panel consisting of gastroenterologists, surgeons, and pathologists, convened by the European Crohn's and Colitis Organisation, performed a systematic literature review. The following topics were covered: in endoscopy: [i] general IBD endoscopy; [ii] disease activity and surveillance; [iii] endoscopy treatment in IBD; in surgery: [iv] medical history with surgical relevance, surgical indication, and strategy; [v] operative approach; [vi] intraoperative disease description; [vii] operative steps; in pathology: [viii] macroscopic assessment and interpretation of resection specimens; [ix] IBD histology, including biopsies, surgical resections, and neoplasia; [x] IBD histology conclusion and report. Statements were developed using a Delphi methodology incorporating two consecutive rounds. Current practice positions were set when ≥ 80% of participants agreed on a recommendation.

RESULTS

Thirty practice positions established a standard terminology for optimal reporting in endoscopy, surgery, and histopathology. Assessment of disease activity, surveillance recommendations, advice to surgeons for operative indication and strategies, including margins and extent of resection, and diagnostic criteria of IBD, as well as guidance for the interpretation of dysplasia and cancer, were handled. A standardised report including a core set of items to include in each specialty report, was defined.

CONCLUSIONS

Interdisciplinary high-quality care requires thorough and standardised reporting across specialties. This topical review offers an actionable framework and practice recommendations to optimise reporting in endoscopy, surgery, and histopathology.

The incidence and prevalence of inflammatory bowel disease in UK primary care: a retrospective cohort study of the IQVIA Medical Research Database

BACKGROUND

Our knowledge of the incidence and prevalence of inflammatory bowel disease (IBD) is uncertain. Recent studies reported an increase in prevalence. However, they excluded a high proportion of ambiguous cases from general practice. Estimates are needed to inform health care providers who plan the provision of services for IBD patients. We aimed to estimate the IBD incidence and prevalence in UK general practice.

METHODS

We undertook a retrospective cohort study of routine electronic health records from the IQVIA Medical Research Database covering 14 million patients. Adult patients from 2006 to 2016 were included. IBD was defined as an IBD related Read code or record of IBD specific medication. Annual incidence and 12-month period prevalence were calculated.

RESULTS

The prevalence of IBD increased between 2006 and 2016 from 106.2 (95% CI 105.2-107.3) to 142.1 (95% CI 140.7-143.5) IBD cases per 10,000 patients which is a 33.8% increase. Incidence varied across the years. The incidence across the full study period was 69.5 (95% CI 68.6-70.4) per 100,000 person years.

CONCLUSIONS

In this large study we found higher estimates of IBD incidence and prevalence than previously reported. Estimates are highly dependent on definitions of disease and previously may have been underestimated.

Test accuracy of faecal calprotectin for inflammatory bowel disease in UK primary care: a retrospective cohort study of the IMRD-UK data

OBJECTIVE

To estimate the test accuracy of faecal calprotectin (FC) for inflammatory bowel disease (IBD) in the primary care setting using routine electronic health records.

DESIGN

Retrospective cohort test accuracy study.

SETTING

UK primary care.

PARTICIPANTS

5970 patients (≥18 years) without a previous IBD diagnosis and with a first FC test between 1 January 2006 and 31 December 2016. We excluded multiple tests and tests without numeric results in units of µg/g.

INTERVENTION

FC testing for the diagnosis of IBD. Disease status was confirmed by a recorded diagnostic code and/or a drug code of an IBD-specific medication at three time points after the FC test date.

MAIN OUTCOME MEASURES

Sensitivity, specificity, and positive and negative predictive values for the differential of IBD versus non-IBD and IBD versus irritable bowel syndrome (IBS) at the 50 and 100 µg/g thresholds.

RESULTS

5970 patients met the inclusion criteria and had at least 6 months of follow-up data after FC testing. 1897 had an IBS diagnosis, 208 had an IBD diagnosis, 31 had a colorectal cancer diagnosis, 80 had more than one diagnosis and 3754 had no subsequent diagnosis. Sensitivity, specificity, and positive and negative predictive values were 92.9% (88.6% to 95.6%), 61.5% (60.2% to 62.7%), 8.1% (7.1% to 9.2%) and 99.6% (99.3% to 99.7%), respectively, at the threshold of 50 µg/g. Raising the threshold to 100 µg/g missed less than 7% additional IBD cases. Longer follow-up had no effect on test accuracy. Overall, uncertainty was greater for specificity than sensitivity. General practitioners' (GPs') referral decisions did not follow the anticipated clinical pathways in national guidance.

CONCLUSIONS

GPs can be confident in excluding IBD on the basis of a negative FC test in a population with low pretest risk but should interpret a positive test with caution. The applicability of national guidance to general practice needs to be improved.

Non-celiac wheat sensitivity: rationality and irrationality of a gluten-free diet in individuals affected with non-celiac disease: a review

Non-celiac gluten or wheat sensitivity (NCWS) is a “clinical entity induced by the ingestion of wheat leading to intestinal and/or extraintestinal symptoms that improve once the wheat-containing foodstuff is removed from the diet, and celiac disease and wheat allergy have been excluded”. This mostly accepted definition raises several points that remain controversial on this condition. In the present review, the authors summarize the most recent advances in the clinic and research on NCWS through an accurate analysis of different studies. We screened PubMed, Medline, Embase, and Scopus using the keywords “non-celiac gluten sensitivity”, “non-celiac wheat sensitivity”, and “diagnosis”. We would like to emphasize two main points, including (A) the controversial clinical and etiological aspects in different trials and experiences with particular attention to the Salerno criteria for the diagnosis of NCWS and (B) the histological aspects. The etiology of NCWS remains controversial, and the relationship with irritable bowel syndrome is obscure. Histologically, the duodenal mucosa may show a variable pattern from unremarkable to a slight increase in the number of T lymphocytes in the superficial epithelium of villi. The endorsement of this disease is based on a positive response to a gluten-free diet for a limited period, followed by the reappearance of symptoms after gluten challenge. The Salerno expert criteria may help to diagnose NCWS accurately. Social media and inaccurate interpretation of websites may jeopardize the diagnostic process if individuals self-label as gluten intolerant.

Indeterminate Colitis - Update on Treatment Options

Indeterminate colitis (IC) is described in approximately 5-15% of patients with inflammatory bowel disease (IBD). It usually reflects a difficulty or lack of clarity in distinguishing between ulcerative colitis (UC) and Crohn's disease (CD) on biopsy or colectomy specimens. The diagnostic difficulty may explain the variability in the reported prevalence and incidence of IC. Clinically, most IC patients tend to evolve over time to a definite diagnosis of either UC or CD. IC has also been interchangeably described as inflammatory bowel disease unclassified (IBDU). This review offers an overview of the available limited literature on the conventional medical and surgical treatments for IC. In contrast to the numerous studies on the medical management of UC and CD, there are very few data from dedicated controlled trials on the treatment of IC. The natural evolution of IC more closely mimics UC. Regarding medical options for treatment, most patients diagnosed with IC are treated similarly to UC, and treatment choices are based on disease severity. Others are managed similarly to CD if there are features suggestive of CD, including fissures, skin tags, or rectal sparing. In medically refractory IC, surgical treatment options are limited and include total proctocolectomy (TPC) and ileal pouch-anal anastomosis (IPAA), with its associated risk factors and complications. Post-surgical complications and pouch failure rates were historically thought to be more common in IC patients, but recent meta-analyses reveal similar rates between UC and IC patients. Future therapies in IBD are focused on known mechanisms in the disease pathways of UC and CD. Owing to the lack of IC-specific studies, clinicians have traditionally and historically extrapolated the data to IC patients based on their symptomatology, clinical course, and endoscopic findings.

Is There a Role for Ileal Pouch Anal Anastomosis in Crohn's Disease?

Traditionally, surgical interventions for colonic Crohn's disease (CD) have been limited to total abdominal colectomy and ileorectal anastomosis, or total proctocolectomy with end ileostomy if there is rectal involvement. However, improved understandings of the biology of CD, as well as the development of biologic therapies, have enabled more limited resections. Here, we review the indications for, and limitations of, specific procedures aiming to preserve intestinal continuity in colonic CD.

Neonatal Presentation of Unremitting Inflammatory Bowel Disease

Very-early-onset inflammatory bowel disease (VEO-IBD) has a distinct phenotype and should be considered a specific entity. VEO-IBD presents with very severe clinical pictures and is frequently known by an indeterminate colitis whose clinical remission is unmanageable. This study examines the case of a neonate with VEO-IBD, not responding to medical and surgical treatment. A 7-day-old Iranian female neonate presented with severe bloody diarrhea, poor feeding, abdominal distention, and dehydration suggesting severe proctocolitis due to an allergy to the protein in cow's milk. The condition did not respond to the elimination of diet for 1 month. Infections, celiac disease, and cystic fibrosis were excluded. Immunological investigations were negative, but antineutrophil cytoplasmic antibodies were positive. Due to the neonate's persistent symptoms and failure to thrive, upper and lower endoscopies were performed, showing ulcerative colitis. At the age of 4 months, she presented with signs and symptoms of toxic colitis and acute intestinal perforation, which prompted an emergency laparotomy. Due to the necrosis of the colon, hemicolectomy and colostomy were done. The patient was resuscitated and rehabilitated and was given glucocorticoid and mesalamine. We believe that the incidence of this problem is increasing, as is shown by the rise in the number of children under 10 years old being diagnosed. These patients require more aggressive therapeutic interventions than older IBD patients to achieve complete remission because they are more likely to have extensive colonic disease.

Prepouch Ileitis After Ileal Pouch-anal Anastomosis: Patterns of Presentation and Risk Factors for Failure of Treatment

BACKGROUND AND AIMS

There is a lack in the literature about prepouch ileitis [PI], in particular regarding risk factors associated with failure of the medical treatment. Aim of the study is to analyse the characteristics of PI patients and to compare those who required surgery with those who were successfully treated with conservative therapy.

METHODS

All cases presenting a diagnosis of PI were included and analysed. Patients eventually requiring surgery were compared with those who were managed conservatively, for symptoms of presentation, endoscopic characteristics, and rate of response to medical treatment. A sub-analysis of outcomes based on the final histology was performed.

RESULTS

The overall incidence of PI among 1286 patients was 4.4% [57], after a median of 6.8 years from pouch surgery. Symptoms included increased frequency [26.4%], outlet obstruction [21%], and bleeding [15.8%]. Afferent limb stenosis affected 49.1% of patients. The comparison showed that patients requiring surgery had a higher rate of Crohn's disease and indeterminate colitis [42.1 vs 0% and 15.8 vs 2.6%, p < 0.0001], outlet obstruction as main symptom [47.4 vs 7.9%, p = 0.0023], and afferent limb stenosis [73.7 vs 36.8%, p = 0.008] at endoscopy. Rate of failure of medical treatment at 5 years was 8.2% in patients with ulcerative colitis and 75% in the presence of both indeterminate colitis and Crohn's disease [p < 0.0001].

CONCLUSIONS

Crohn's disease, indeterminate colitis, and stenosis with outlet obstruction are risk factors for failure of treatment after diagnosis of PI. Early aggressive therapy and surgery should be considered in these cases.

Diagnostic dilemmas in chronic inflammatory bowel disease

Histopathological assessment of biopsy and resection specimens of chronic inflammatory bowel disease (CIBD), or possible CIBD, forms a significant component of the routine workload in most tissue pathology laboratories. In this review, we have chosen selected areas of particular diagnostic difficulty in CIBD pathology, providing key advice for pathology reporting. Those mimics of CIBD which have the greatest potential for misdiagnosis are discussed, particularly the wide range of infectious colitides which represent possible diagnostic pitfalls. The most important distinguishing features between the two main forms of CIBD, ulcerative colitis and Crohn's disease, are addressed, first in relation to resection specimens, and then with emphasis on features which may also be diagnostically useful in endoscopic biopsy material. The importance of assessment of the index endoscopic specimen is stressed, before treatment has been instigated, along with careful correlation with clinical and endoscopic features. Problems in the assessment of post-surgical CIBD specimens are described and then the role of upper gastrointestinal pathology specimens in diagnosing both Crohn's disease and ulcerative colitis, with increased recognition of upper gastrointestinal tract involvement in the latter condition. Finally, with recent developments in endoscopic surveillance techniques and local excision options, modern approaches to reporting and managing neoplasia complicating CIBD are reviewed.

Clinical Aspects of Idiopathic Inflammatory Bowel Disease: A Review for Pathologists

CONTEXT

-Idiopathic inflammatory bowel disease manifests with different clinical phenotypes showing varying behavior and risk for neoplasia. The clinical questions that are posed to pathologists differ depending on phase of the disease and the clinical circumstances. Understanding the clinical aspects of the dynamic disease process will enhance the role of pathology in optimizing the care of patients with inflammatory bowel disease.

OBJECTIVE

-To review clinical and surgical aspects of inflammatory bowel disease that are relevant to practicing pathologists.

DATA SOURCES

-The literature was reviewed.

CONCLUSIONS

-Diagnosis and management of inflammatory bowel disease require an integrated evaluation of clinical, endoscopic, radiologic, and pathologic features. Therefore, close interaction between clinicians and pathologists is crucial. Having this team approach improves understanding of the pertinent clinical and surgical aspects of the disease and assists in the recognition of unusual presentation of variants, as well as mimics of idiopathic inflammatory bowel disease, by pathologists.

Essential role of small bowel capsule endoscopy in reclassification of colonic inflammatory bowel disease type unclassified

AIM

To evaluate the role of small bowel capsule endoscopy (SBCE) on the reclassification of colonic inflammatory bowel disease type unclassified (IBDU).

METHODS

We performed a multicenter, retrospective study including patients with IBDU undergoing SBCE, between 2002 and 2014. SBCE studies were reviewed and the inflammatory activity was evaluated by determining the Lewis score (LS). Inflammatory activity was considered significant and consistent with Crohn’s disease (CD) when the LS ≥ 135. The definitive diagnosis during follow-up (minimum 12 mo following SBCE) was based on the combination of clinical, analytical, imaging, endoscopic and histological elements.

RESULTS

Thirty-six patients were included, 21 females (58%) with mean age at diagnosis of 33 ± 13 (15-64) years. The mean follow-up time after the SBCE was 52 ± 41 (12-156) mo. The SBCE revealed findings consistent with significant inflammatory activity in the small bowel (LS ≥ 135) in 9 patients (25%); in all of them the diagnosis of CD was confirmed during follow-up. In 27 patients (75%), the SBCE revealed no significant inflammatory activity (LS < 135); among these patients, the diagnosis of Ulcerative Colitis (UC) was established in 16 cases (59.3%), CD in 1 case (3.7%) and 10 patients (37%) maintained a diagnosis of IBDU during follow-up. A LS ≥ 135 at SBCE had a sensitivity = 90%, specificity = 100%, positive predictive value = 100% and negative predictive value = 94% for the diagnosis of CD.

CONCLUSION

SBCE proved to be fundamental in the reclassification of patients with IBDU. Absence of significant inflammatory activity in the small intestine allowed exclusion of CD in 94% of cases.

Human alpha defensin 5 is a candidate biomarker to delineate inflammatory bowel disease

Inability to distinguish Crohn's colitis from ulcerative colitis leads to the diagnosis of indeterminate colitis. This greatly effects medical and surgical care of the patient because treatments for the two diseases vary. Approximately 30 percent of inflammatory bowel disease patients cannot be accurately diagnosed, increasing their risk of inappropriate treatment. We sought to determine whether transcriptomic patterns could be used to develop diagnostic biomarker(s) to delineate inflammatory bowel disease more accurately. Four patients groups were assessed via whole-transcriptome microarray, qPCR, Western blot, and immunohistochemistry for differential expression of Human α-Defensin-5. In addition, immunohistochemistry for Paneth cells and Lysozyme, a Paneth cell marker, was also performed. Aberrant expression of Human α-Defensin-5 levels using transcript, Western blot, and immunohistochemistry staining levels was significantly upregulated in Crohn's colitis, p< 0.0001. Among patients with indeterminate colitis, Human α-Defensin-5 is a reliable differentiator with a positive predictive value of 96 percent. We also observed abundant ectopic crypt Paneth cells in all colectomy tissue samples of Crohn's colitis patients. In a retrospective study, we show that Human α-Defensin-5 could be used in indeterminate colitis patients to determine if they have either ulcerative colitis (low levels of Human α-Defensin-5) or Crohn's colitis (high levels of Human α-Defensin-5). Twenty of 67 patients (30 percent) who underwent restorative proctocolectomy for definitive ulcerative colitis were clinically changed to de novo Crohn's disease. These patients were profiled by Human α-Defensin-5 immunohistochemistry. All patients tested strongly positive. In addition, we observed by both hematoxylin and eosin and Lysozyme staining, a large number of ectopic Paneth cells in the colonic crypt of Crohn's colitis patient samples. Our experiments are the first to show that Human α-Defensin-5 is a potential candidate biomarker to molecularly differentiate Crohn's colitis from ulcerative colitis, to our knowledge. These data give us both a potential diagnostic marker in Human α-Defensin-5 and insight to develop future mechanistic studies to better understand crypt biology in Crohn's colitis.

Microbiome, Metabolome and Inflammatory Bowel Disease

Inflammatory Bowel Disease (IBD) is a multifactorial disorder that conceptually occurs as a result of altered immune responses to commensal and/or pathogenic gut microbes in individuals most susceptible to the disease. During Crohn’s Disease (CD) or Ulcerative Colitis (UC), two components of the human IBD, distinct stages define the disease onset, severity, progression and remission. Epigenetic, environmental (microbiome, metabolome) and nutritional factors are important in IBD pathogenesis. While the dysbiotic microbiota has been proposed to play a role in disease pathogenesis, the data on IBD and diet are still less convincing. Nonetheless, studies are ongoing to examine the effect of pre/probiotics and/or FODMAP reduced diets on both the gut microbiome and its metabolome in an effort to define the healthy diet in patients with IBD. Knowledge of a unique metabolomic fingerprint in IBD could be useful for diagnosis, treatment and detection of disease pathogenesis.

Nonbloody Diarrhea but Not Significant Weight Loss at Diagnosis Is Associated with the Development of Denovo Crohn's Disease After Ileal Pouch-anal Anastomosis for Ulcerative Colitis

BACKGROUND

Denovo Crohn's disease (CD) develops in 5% to 10% of patients after ileal pouch-anal anastomosis (IPAA) for ulcerative colitis (UC) leading to increased morbidity and rates of pouch failure. Initial nonbloody diarrhea and weight loss at diagnosis are independent risk factors for a change in diagnosis from UC to CD in nonsurgical patients. We investigated whether these features were risk factors for denovo CD in a longitudinal cohort of patients with UC undergoing IPAA.

METHODS

Prospective profiles of patients with UC undergoing IPAA followed over a 22-year period by 1 surgeon were analyzed. Denovo CD was diagnosed when mucosal inflammation (5 or more ulcers) involved the small bowel mucosa proximal to the ileal pouch any time after surgery and/or when a pouch fistula or other perianal complication developed more than 3 months after ileostomy closure. Patients with inflammatory bowel disease unclassified, acute pouchitis, chronic pouchitis, and those lost to follow-up were excluded from analysis. Cox regression analysis was performed for statistical significance.

RESULTS

Of the 199 study patients included in the analysis, denovo CD developed in 42 patients (21%). Patients who developed denovo CD had an increased incidence of nonbloody diarrhea (n = 12; 29%) compared with patients who had no evidence of pouch inflammation (n = 25; 16%) (P = 0.03). In contrast, the incidence of weight loss was not significantly increased in patients with denovo CD (n = 7; 17%) compared with patients who never had pouch inflammation (n = 16; 10%) (P = 0.12).

CONCLUSIONS

Initial nonbloody diarrhea is associated with denovo CD after IPAA. This association warrants close consideration before surgery.