Laboratory assessment of inflammatory bowel disease

Intestinal Permeability Measured by Urinary Sucrose Excretion Correlates with Serum Zonulin and Faecal Calprotectin Concentrations in UC Patients in Remission

Background and Aims

Ulcerative colitis (UC) is associated with an increased intestinal permeability, possibly through a dysbiosis of intestinal bacteria. We investigated which markers are most relevant to assess intestinal permeability in UC patients and whether probiotics had an effect on these markers.

Methods

In this twelve-week placebo-controlled randomized double-blind study, twenty-five subjects with UC in remission received either placebo or a multispecies probiotics. Samples of blood, urine, and faeces were taken at baseline, week 6, and week 12 to assess intestinal permeability and inflammation. Diaries and Bristol stool scale were kept to record stool frequency and consistency. Quality of life was scored from 32–224 with the inflammatory bowel disease questionnaire (IBD-Q).

Results

This group of UC patients, in clinical remission, did not show increased intestinal permeability at baseline of this study. During the study, no significant group or time effects were found for intestinal permeability measured by the 5-sugar absorption test, serum zonulin, and faecal zonulin. Likewise, the inflammatory markers C-reactive protein (CRP), calprotectin, and the cytokines IFNγ, TNFα, IL-6, and IL-10 were not significantly affected. Stool frequency and consistency were not significantly affected either. The IBD-Q score, 194 for the probiotics group and 195 for the placebo group, remained unaffected. Correlations were tested between all outcomes; urinary sucrose excretion was significantly correlated with serum zonulin (r = 0.62) and faecal calprotectin (r = 0.55). Faecal zonulin was not significantly correlated with any of the other markers.

Conclusion

Serum zonulin may be a more relevant biomarker of intestinal permeability than faecal zonulin, due to its correlation with other biomarkers of intestinal permeability. UC patients in remission did not show an effect of the probiotic treatment or a change in gut permeability. This should not discourage further studies because effects might be present during active disease or shortly after a flare up.

Nutritional and probiotic supplementation in colitis models

In vitro and animals models have long been used to study human diseases and identify novel therapeutic approaches that can be applied to combat these conditions. Ulcerative colitis and Crohn's disease are the two main entities of inflammatory bowel disease (IBD). There is an intricate relationship between IBD features in human patients, in vitro and animal colitis models, mechanisms and possible therapeutic approaches in these models, and strategies that can be extrapolated and applied in humans. Malnutrition, particularly protein-energy malnutrition and vitamin and micronutrient deficiencies, as well as dysregulation of the intestinal microbiota, are common features of IBD. Based on these observations, dietary supplementation with essential nutrients known to be in short supply in the diet in IBD patients and with other molecules believed to provide beneficial anti-inflammatory effects, as well as with probiotic organisms that stimulate immune functions and resistance to infection has been tested in colitis models. Here we review current knowledge on nutritional and probiotic supplementation in in vitro and animal colitis models. While some of these strategies require further fine-tuning before they can be applied in human IBD patients, their intended purpose is to prevent, delay or treat disease symptoms in a non-pharmaceutical manner.

Mural inflammation in Crohn disease: location-matched histologic validation of MR imaging features

PURPOSE

To validate proposed magnetic resonance (MR) imaging features of Crohn disease activity against a histopathologic reference.

MATERIALS AND METHODS

Ethical permission was given by the University College London hospital ethics committee, and informed written consent was obtained from all participants. Preoperative MR imaging was performed in 18 consecutive patients with Crohn disease undergoing elective small-bowel resection. The Harvey-Bradshaw index, the C-reactive protein level, and disease chronicity were recorded. The resected bowel was retrospectively identified at preoperative MR imaging, and wall thickness, mural and lymph node/cerebrospinal fluid (CSF) signal intensity ratios on T2-weighted fat-saturated images, gadolinium-based contrast material uptake, enhancement pattern, and mesenteric signal intensity on T2-weighted fat-saturated images were recorded. Precise histologic matching was achieved by imaging the ex vivo surgical specimens. Histopathologic grading of acute inflammation with the acute inflammatory score (AIS) (on the basis of mucosal ulceration, edema, and quantity and depth of neutrophilic infiltration) and the degree of fibrostenosis was performed at each site, and results were compared with MR imaging features. Data were analyzed by using linear regression with robust standard errors of the estimate.

RESULTS

AIS was positively correlated with mural thickness and mural/CSF signal intensity ratio on T2-weighted fat-saturated images (P < .001 and P = .003, respectively) but not with mural enhancement at 30 and 70 seconds (P = .50 and P = .73, respectively). AIS was higher with layered mural enhancement (P < .001), a pattern also commonly associated with coexisting fibrostenosis (75%). Mural/CSF signal intensity ratio on T2-weighted fat-saturated images was higher in histologically edematous bowel than in nonedematous bowel (P = .04). There was no correlation between any lymph node characteristic and AIS.

CONCLUSION

Increasing mural thickness, high mural signal intensity on T2-weighted fat-saturated images, and a layered pattern of enhancement reflect histologic features of acute small-bowel inflammation in Crohn disease.

MRI scoring system including dynamic motility evaluation in assessing the activity of Crohn's disease of the terminal ileum

RATIONALE AND OBJECTIVES

We sought to investigate the value of a MRI scoring system including dynamic motility evaluation in the assessment of small bowel Crohn's disease activity.

MATERIALS AND METHODS

From March 2005 to December 2006, 52 patients with suspected Crohn's disease onset or relapse underwent MRI on a 1.5-T magnet. Bowel distention was achieved orally assuming a mean of 1.6 L of a polyethyleneglycol (PEG) preparation. Per-patient assessment of disease activity was based on a scoring system including evaluation of morphology and motility of the small bowel and perivisceral structures (true-FISP, cine-true-FISP, and HASTE T2W sequences) and dynamic assessment of parietal contrast enhancement (FLASH T1W sequence). Patients were included in three categories, using endoscopic biopsy as the standard reference: no activity/quiescent disease, mild activity, or moderate-to-severe activity. Patients without terminal ileum involvement were excluded from data analysis.

RESULTS

MRI allowed a detailed and panoramic evaluation of the small bowel in all subjects examined. MRI properly assessed 14 of 16 (87.5%) cases of no activity/quiescent disease, 12 of 14 (85.7%) cases of mild activity, and 15 of 15 (100%) cases of severe activity. Overall, activity score led to a per-patient misdiagnosis of disease activity in a nonsignificant proportion of subjects (4 of 45; 8.8%) (P > .05), determining two false-positive and two false-negative results of mild disease activity. Sensitivity, specificity, PPV, NPV, and overall accuracy in assessing disease activity were 93.1%, 87.5%, 93.1%, 87.5%, and 91.1%, respectively.

CONCLUSION

Accurate assessment of Crohn's disease activity is achieved by using an activity score providing an overall interpretation of MRI findings.

Faecal calprotectin in the assessment of Crohn's disease activity

BACKGROUND

Clinical and laboratory assessment of activity in Crohn's disease (CD) correlate poorly with endoscopic findings. Calprotectin is a calcium-binding protein abundant in neutrophil cytosol, and extremely stable in faeces. Faecal calprotectin (FC) is an excellent surrogate marker of neutrophil influx into the bowel lumen.

AIM

To assess whether FC concentration from a spot stool sample reliably detects active inflammation in patients with CD.

DESIGN

Cross-sectional comparative study.

METHODS

Subjects had a previously confirmed diagnosis of CD and were suspected on clinical grounds to be in the midst of a relapse. Thirty-five entered the study; they underwent radiolabelled white cell scanning (WCS) and had a stool sample collected for calprotectin measurement on the same day. A Crohn's disease activity index (CDAI) was also calculated for each. The WCS scans were scored at six standard sites to give a mean total, 'extent', 'severity' and 'combined extent and severity' scores.

RESULTS

FC was significantly and positively correlated with mean total (r = 0.73, p < 0.001), 'extent' (r = 0.71, p < 0.001), 'severity' (r = 0.64, p < 0.001) and combined 'extent and severity' WCS scores (r = 0.71, p < 0.001). A cut-off of faecal calprotectin > 100 microg/g gave a sensitivity of 80%, specificity of 67%, positive predictive value of 87% and a negative predictive value of 64% in identifying those with and without any inflammation on WCS. There was, however, no significant correlation between CDAI and mean total WCS score (r = 0.21, p = 0.24), nor between CDAI and FC (r = 0.33, p = 0.06).

DISCUSSION

While the CDAI does not accurately reflect inflammatory activity in CD, a one-off FC reliably detects the presence or absence of intestinal inflammation in adult patients with CD, compared to WCS.

Fecal calprotectin: validation as a noninvasive measure of bowel inflammation in childhood inflammatory bowel disease

BACKGROUND

Calprotectin is an abundant neutrophil protein, which is extremely stable in feces. This study aimed to validate fecal calprotectin as a marker of bowel inflammation against invasive measures in children with inflammatory bowel disease (IBD), including colitis and small bowel Crohn disease.

METHODS

Fecal calprotectin was measured using a simple enzyme-linked immunosorbent assay in 36 spot stool samples from 22 children before colonoscopy and from 14 children before technetium-99 (99Tc) scanning. Using standard scoring systems, the severity of inflammation was assessed macroscopically and histologically at six standard sites in those who underwent colonoscopy and also at six standard sites in those who underwent 99Tc scanning. The subscores from each site were summated to give combined severity and extent scores for macroscopic and for histologic inflammation in the group undergoing colonoscopy and total inflammation in the group undergoing 99Tc scanning.

RESULTS

In the 22 children who underwent colonoscopy, median fecal calprotectin was 4.9 mg/L (0.1-272.5 mg/L) (range). Disease groups included six normal cases, nine ulcerative colitis cases, two isolated Crohn colitis cases, two indeterminate colitis cases, and three allergic colitis cases. Fecal calprotectin correlated closely with colonic macroscopic inflammation (r = 0.75, P < 0.001) and histologic inflammation (r = 0.85, P < 0.001). Of the 14 children undergoing 99Tc scanning, 10 had Crohn disease, 3 had ulcerative colitis, and 1 had allergic colitis. Median fecal calprotectin was 9.1 mg/L (0.3-141.7 mg/L), and this correlated closely with the 99Tc scanning score (r = 0.80, P = 0.001).

CONCLUSION

Fecal calprotectin correlates closely with the best invasive measures of colonic and small bowel inflammation in childhood inflammatory bowel disease. As a sensitive objective measure of bowel inflammation that is risk-free and noninvasive, fecal calprotectin lends itself particularly to the monitoring of and assessment of therapeutic interventions in children with inflammatory bowel disease.

Fecal calprotectin as a measure of disease activity in childhood inflammatory bowel disease

BACKGROUND

Calprotectin is an abundant neutrophil protein that is extremely stable in feces. The aim of this study was to assess the effectiveness of fecal calprotectin as a noninvasive measure of disease activity in childhood inflammatory bowel disease (IBD) by comparison to a modified Lloyd-Still and Green score and laboratory inflammatory indices.

METHODS

Spot fecal samples from 37 children with IBD and 31 control children were sent by ordinary mail to the laboratory. Fecal calprotectin concentration was measured by an in-house enzyme linked immunosorbent assay (ELISA). A modified Lloyd-Still & Green score (mLSS) was calculated for each child with IBD within 10 days of obtaining the fecal sample.

RESULTS

Compared with control values (median, range) (2.1, 0.5-6.3 mg/L), fecal calprotectin was increased in 16 children with ulcerative colitis, (11.5, 0.6-272.5 mg/L, P < 0.001) and in 21 children with Crohn disease, (14.0, 0.7-59.7 mg/L, P < 0.001). Twelve "moderately affected" children (mLSS of 35-65) had higher fecal calprotectin concentrations (22.2, 2.7-141.7 mg/L) than 25 "mildly affected" children (mLSS > 65), (10.3, 0.6-272.5 mg/L, P = 0.002). For the total IBD group, fecal calprotectin concentration correlated negatively with the mLSS (r = -0.61, P < 0.001). It also correlated negatively with serum albumin concentration (r = -0.49, P = 0.002) and positively with erythrocyte sedimentation rate (r = 0.40, P = 0.01).

CONCLUSIONS

Fecal calprotectin seems to reflect bowel inflammation in children with IBD. As a simple, safe, noninvasive test, it has the potential to reduce the number of invasive investigations performed in these children.

Intestinal permeability test as a predictor of clinical course in Crohn's disease

OBJECTIVE

The clinical course of Crohn's disease is often unpredictable. The aim of this study was to select the most useful parameters able to predict clinical relapses.

METHODS

One hundred-thirty Crohn's disease patients in clinical remission were followed every 4 months for 2 yr or until clinical relapse. Demographic and clinical data were recorded and intestinal permeability (lactulose/mannitol [L/M] test) and biochemical tests (white blood cell count, erythrocyte sedimentation rate, C-reactive protein, alpha1 acid glycoprotein, and serum iron) were performed at study entry. A subgroup of 54 patients had clinical follow-up and repeated tests every 4 months.

RESULTS

Fifty-two patients (40%) relapsed during the 2-yr follow-up. A significant correlation was found between relapse and gender (p = 0.030) but not between relapse and age, extent and type of disease, previous surgery, or therapy. Increased L/M test (p = 0.0001) and decreased serum iron level (p = 0.0057) were associated with clinical relapse. Time-dependent analysis, performed on patients receiving serial evaluation, showed that L/M test alteration was the only variable that could predict a relapse (RR 8.84, 95% confidence interval [CI] 1.41-53.37; p < 0.05).

CONCLUSIONS

The L/M test identifies Crohn's disease patients in apparent remission, but with a high risk of clinical relapse, better than clinical and biochemical indices. Different treatment strategies might be suggested for this subgroup of patients.

Inflammatory bowel disease in children

IBD is one of the most significant chronic diseases afflicting children and adolescents. As in adults, UC and CD constitute the two major disease entities, with many of the characteristics of these two diseases being similar in adults and children. With technical advances, a complete endoscopic examination of the colon and terminal ileum can be performed in most children without difficulty. There are, however, a number of aspects of the presentation, course, and management of these diseases that are unique to the pediatric population. Because the impact of inadequate nutrition is much greater in the growing child than in adults, growth failure is a common, serious complication of malnutrition in this population. The psychological impact of a chronic illness on both the developing child and the family can also be significant. The management of this population is further complicated by the lack of adequate studies that assess not only the effect of a medical or surgical therapy on disease activity, but also address the issues of growth and pubertal development. It has been a challenge to extrapolate data from adult studies to the pediatric population. The management of children and adolescents requires a critical understanding of the differences between pediatric and adult patients to maximize growth potential and minimize longterm sequelae of treatment. After a long period of limited controlled studies, however, collaborative efforts are underway to investigate most aspects of pediatric IBD, and we look forward to exciting advances toward the optimal management of children and adolescents with IBD.

Microalbuminuria in inflammatory bowel disease

Microalbuminuria independently predicts the development of nephropathy and increased cardiovascular morbidity and mortality in diabetic patients, but it may be an indicator of the acute phase response. This study examined microalbuminuria as a marker of the acute phase response in patients with inflammatory bowel disease and correlated it with the disease activity in 95 patients with inflammatory bowel disease (ulcerative colitis (n = 52), Crohn's disease (n = 43)) determined by the simple index of Harvey and Bradshaw. Fifty patients were in complete clinical remission and 45 patients had active disease. Microalbuminuria was detected in all patients with inflammatory bowel disease (147 (17) v 18 (2) microgram/min, inflammatory bowel disease v controls mean (SEM), p < 0.007). Patients with active inflammatory bowel disease had higher concentrations of microalbuminuria compared with patients in remission (206 (19) v 65 (8) microgram/min, mean (SEM), p < 0.0001). Eight patients with active inflammatory bowel disease who were sequentially followed up with measurements of microalbuminuria had significantly lower values, when the disease was inactive (active inflammatory bowel disease 192 (44) v inactive inflammatory bowel disease 64 (14) microgram/min, p < 0.03). There was a significant correlation with the simple index of Harvey and Bradshaw (r = 0.818, p < 0.0001). Microalbuminuria values were significantly lower in inflammatory bowel disease patients in remission, maintained with olsalazine compared with those patients maintained with mesalazine and salazopyrine, but no significant difference was seen in values of microalbuminuria in active inflammatory bowel disease patients receiving different salicylates. This study also measured serum amyloid-A as an indicator of the acute phase response in the same patients. Serum amyloid-A was significantly increased in active disease compared with inactive disease (151 (43) v 33 (7) or controls 11 (2) micrograms/ml, p < 0.05). In conclusion microalbuminuria is present in abnormal amounts in all patients with active inflammatory bowel disease, and values fall when the disease is quiescent. Microalbuminuria is probably a consequence of an acute phase response and provides a simple, rapid, and inexpensive test, which has the potential to monitor inflammatory bowel disease activity and response to treatment.

Inflammatory bowel disease

Inflammatory bowel disease in children encompasses at least two forms of intestinal inflammation: ulcerative colitis and Crohn's disease. These two disease processes are differentiated based on clinical presentation, radiologic findings, endoscopic findings, histologic evaluation, and exclusion of alternative causes. The treatment and operative interventions are reviewed.

Diagnostic techniques in inflammatory bowel disease

Additional diagnostic modalities exist in the clinical laboratory, as outlined in Tables 1 through 3. In general, the usefulness of each test in determining the optimal therapy for a patient with inflammatory bowel disease is inversely related to the cost of that test, with history and physical examination ranking first. Each additional test must be ordered only if the result can answer a specific question necessary for the care of the patient.

Evaluation of different laboratory tests and activity indices reflecting the inflammatory activity of Crohn's disease

In a prospective study we compared the usefulness of various laboratory tests (albumin, alpha-1-proteinase inhibitor (A1PI), cholinesterase (CHE), C-reactive protein, erythrocyte sedimentation rate, hematocrit) and activity indices (CDAI, VHAI) in relation to the disease activity by endoscopic criteria. Except for hematocrit highly significant differences (p less than 0.0005) of the mean values of all test results were found for patients without or with slight mucosal lesions compared with patients with severe inflammation of the mucosa. Further analysis of the data indicates the highest test efficiency (84%), sensitivity (80%), and specificity (88.6%) for CHE. CHE showed good correlations to all other tests; the highest correlation was found between CHE and VHAI (r = -0.78). We suggest that a suppression of CHE synthesis mediated by endotoxins and cytokines rather than an increased intestinal loss explains the decreased CHE in severe Crohn's disease. It is concluded from the data that CHE is a useful test to assess the inflammatory activity of Crohn's disease.

A simple method for the measurement of different forms of alpha 1 proteinase inhibitor in the faeces of patients with Crohn's disease

Alpha-1 proteinase inhibitor (alpha 1PI), formerly named alpha 1-antitrypsin, is excreted in the faeces of patients with Crohn's disease as isoforms clearly separated by SDS-PAGE and immunoblot analysis. Relapses in Crohn's disease are generally associated with the appearance in faeces of M(rs) 51,000 and 45,000 glycosylated forms of alpha 1PI, as compared with normal subjects and most of the patients in quiescent phases of their disease who excrete an M(r) 38,000 unglycosylated form of alpha 1PI. We used their differential Concanavalin-A reactivity to design a specific test. The proposed assay is potentially helpful for the follow-up of patients under therapy and for early recognition of attacks of Crohn's disease.

Health status in inflammatory bowel disease. Biological and behavioral considerations

The existing clinical measures of disease activity for inflammatory bowel disease are insufficient to explain a patient's illness experience or health outcomes. Although many disease activity measures have been devised, they are not widely accepted by clinicians because existing ones are no better than a carefully obtained clinical assessment. Furthermore, health status is determined not only by disease activity, but also by the psychological state, cultural influences, degree of social support, and effects of complications, previous surgery, and medication. To develop more accurate appraisals of the impact and severity of IBD, we must prospectively evaluate the biological and psychosocial measures that predict clinically relevant outcomes. We should then be able to develop statistically weighted scales related to specific outcome variables. Such knowledge will help us to develop more sensitive measures of illness, particularly in patients with mild disease for whom present indices are insensitive. This type of assessment should also aid in the understanding of health care utilization, medical vs. surgical options, resource allocation, and the efficacy of therapeutic trials.

Clinical, biological, and endoscopic picture of attacks of Crohn's disease. Evolution on prednisolone. Groupe d'Etude Thérapeutique des Affections Inflammatoires Digestives

One hundred forty-two patients with active colonic or ileocolonic Crohn's disease were included in a multicenter prospective study. Data collection included 28 clinical, biological, and endoscopic items; the latter were recorded according to a standardized colonoscopic protocol; a previously validated endoscopic index of severity was calculated. Oral prednisolone (1 mg/kg body wt per day) was started and maintained until clinical remission and for at least 3 and at most 7 wk. A second clinical biological and endoscopic evaluation was then performed. At initial colonoscopy, mucosal lesions were, by decreasing order of frequency, superficial ulcerations, deep ulcerations, mucosal edema, erythema, pseudopolyps, aphthoid ulcers, ulcerated stenosis, and nonulcerated stenosis (93%, 74%, 48%, 44%, 41%, 35%, 10%, 8%, and 2% of cases, respectively). No correlation was found between the clinical activity index and any of the endoscopical data (lesion frequency and surface, endoscopic severity index). Ninety-two percent of patients underwent clinical remission within 7 wk of treatment. None of the 28 clinical biological and endoscopical items collected just before treatment could predict clinical response to steroids. Only 38 of the 131 patients in clinical remission were also in endoscopic remission. In conclusion, (a) the description and severity of colonoscopic lesions in active Crohn's disease have been quantified; (b) no correlation exists between clinical severity and nature, surface, or severity of endoscopic lesions; (c) Oral prednisolone (1 mg/kg body wt per day) induces a clinical remission in 92% of patients within 7 wk; (d) resistance to steroids cannot be predicted from the data collected before treatment onset; and (e) only 29% of patients in clinical remission also achieve endoscopic remission.

Clinical activity assessment in inflammatory bowel disease

Standardized methods of making and recording clinical observations of patients with inflammatory bowel disease are needed for the conduct of controlled clinical trials and for the application of the results of such trials to clinical practice. A number of attempts to develop such methods have been made since the early 1950s, and such efforts continue at present. A universally accepted and acceptable clinical instrument to measure the disease activity of either Crohn's disease or ulcerative colitis will probably never be achieved. However, if interested clinicians can agree on a basic set of observations and how to make and record them, accurate comparisons of therapeutic outcomes across time and space will become possible. Toward this goal several groups of clinicians are currently working.