Abdominal pain in patients with inflammatory bowel disease in remission: A prospective study on contributing factors.

BACKGROUND: Abdominal pain is highly prevalent in patients with inflammatory bowel disease (IBD) in remission, but the aetiology is incompletely understood. AIM: To investigate the association of clinical, lifestyle and psychosocial factors with abdominal pain in patients with IBD in remission. METHODS: We performed a prospective multicentre study enrolling consecutive patients with IBD. Data were collected between 1 January 2020 and 1 July 2021, using myIBDcoach, an established remote monitoring platform for IBD. Chronic abdominal pain in IBD in remission (IBDremissionPain+) was defined as abdominal pain score ≥3 (0-10 NRS) on ≥1/3 of all assessments, combined with faecal calprotectin <150 µg/g in 90 days around periodic assessments. Disease activity, lifestyle and psychosocial factors were assessed every 1-3 months during 18 months. Using linear mixed models, the association of these factors with abdominal pain over time was analysed. RESULTS: We included 559 patients, of whom 429 (76.7%) remained in biochemical remission. Of these, 198 (46.2%) fulfilled the criteria for chronic abdominal pain. IBDremissionPain+ patients were characterised by female sex, younger age, higher BMI, and shorter disease duration. They reported more often or higher levels of stress, fatigue, depressive and anxiety symptoms, and life events (all p < 0.001). In the multivariable analysis, sex, disease entity, fatigue, depressive symptoms and life events were associated with abdominal pain over time (all p < 0.05). CONCLUSION: In this cohort of patients with IBD in remission, abdominal pain was common and associated with psychosocial factors. A more holistic treatment approach for patients with IBD suffering from abdominal pain may improve quality of care and subjective wellbeing.

A combination of fecal calprotectin and human beta-defensin 2 facilitates diagnosis and monitoring of inflammatory bowel disease.

Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) show a large overlap in clinical presentation, which presents diagnostic challenges. As a consequence, invasive and burdensome endoscopies are often used to distinguish between IBD and IBS. Here, we aimed to develop a noninvasive fecal test that can distinguish between IBD and IBS and reduce the number of endoscopies.We used shotgun metagenomic sequencing to analyze the composition and function of gut microbiota of 169 IBS patients, 447 IBD patients and 1044 population controls and measured fecal Calprotectin (FCal), human beta defensin 2 (HBD2), and chromogranin A (CgA) in these samples. These measurements were used to construct training sets (75% of data) for logistic regression and machine learning models to differentiate IBS from IBD and inactive from active IBD. The results were replicated on test sets (remaining 25% of the data) and microbiome data obtained using 16S sequencing.Fecal HBD2 showed high sensitivity and specificity for differentiating between IBD and IBS (sensitivity = 0.89, specificity = 0.76), while the inclusion of microbiome data with biomarkers (HBD2 and FCal) showed a potential for improvement in predictive power (optimal sensitivity = 0.87, specificity = 0.93). Shotgun sequencing-based models produced comparable results using 16S-sequencing data. HBD2 and FCal were found to have predictive power for IBD disease activity (AUC ≈ 0.7).HBD2 is a novel biomarker for IBD in patients with gastro-intestinal complaints, especially when used in combination with FCal and potentially in combination with gut microbiome data.

Development, content validity, and cross-cultural adaptation of a patient-reported outcome measure for real-time symptom assessment in irritable bowel syndrome.

BACKGROUND: End-of-day questionnaires, which are considered the gold standard for assessing abdominal pain and other gastrointestinal (GI) symptoms in irritable bowel syndrome (IBS), are influenced by recall and ecological bias. The experience sampling method (ESM) is characterized by random and repeated assessments in the natural state and environment of a subject, and herewith overcomes these limitations. This report describes the development of a patient-reported outcome measure (PROM) based on the ESM principle, taking into account content validity and cross-cultural adaptation. METHODS: Focus group interviews with IBS patients and expert meetings with international experts in the fields of neurogastroenterology & motility and pain were performed in order to select the items for the PROM. Forward-and-back translation and cognitive interviews were performed to adapt the instrument for the use in different countries and to assure on patients' understanding with the final items. KEY RESULTS: Focus group interviews revealed 42 items, categorized into five domains: physical status, defecation, mood and psychological factors, context and environment, and nutrition and drug use. Experts reduced the number of items to 32 and cognitive interviewing after translation resulted in a few slight adjustments regarding linguistic issues, but not regarding content of the items. CONCLUSIONS AND INFERENCES: An ESM-based PROM, suitable for momentary assessment of IBS symptom patterns was developed, taking into account content validity and cross-cultural adaptation. This PROM will be implemented in a specifically designed smartphone application and further validation in a multicenter setting will follow.

Rome III vs Rome IV criteria for irritable bowel syndrome: A comparison of clinical characteristics in a large cohort study.

BACKGROUND: The Rome criteria for irritable bowel syndrome (IBS) have been revised and are expected to apply only to the subset of Rome III IBS subjects with abdominal pain as predominant symptom, occurring at least once a week. The aim of this study was to determine the percentage of Rome III IBS subjects that fulfills Rome IV criteria and to evaluate differences between Rome IV-positive and Rome IV-negative subjects. METHODS: Four hundred and four Rome III IBS subjects completed a 14-day end-of-day symptom diary, the Gastrointestinal Symptom Rating Scale (GSRS), Hospital Anxiety and Depression Scale, and RAND 36-item Short-Form Health Survey (SF-36). Diary-based surrogate Rome IV criteria were defined as occurrence of abdominal pain at least 1 day each week with a severity of ≥2 (mild; definition 1) or ≥3 (considerable; definition 2). KEY RESULTS: Using surrogate Rome IV criteria, 353 (87.4%, definition 1) and 249 (61.6%, definition 2) subjects were defined as Rome IV positive. These patients were more often female, younger, and recruited from secondary/tertiary care compared with Rome IV-negative subjects. They also presented with higher abdominal pain scores and gastrointestinal (GI) symptom severity on both end-of-day diary and GSRS, higher psychological symptom scores, and lower quality of life compared with Rome IV-negative subjects. CONCLUSIONS AND INFERENCES: The Rome IV IBS population likely reflects a subgroup of Rome III IBS patients with more severe GI symptomatology, psychological comorbidities, and lower quality of life. This implies that results from Rome III IBS studies may not be directly comparable to those from Rome IV IBS populations.

Habitual diet and diet quality in Irritable Bowel Syndrome: A case-control study.

BACKGROUND: Diet is considered to be a key factor in symptom generation in Irritable Bowel Syndrome (IBS) and patients tend to exclude food products from their diet in pursue of symptom relief, which may impair diet quality. METHODS: We evaluated habitual dietary intake in IBS patients with regard to nutrients and food products using an extensive food frequency questionnaire. One hundred ninety-four IBS patients were compared to 186 healthy controls using multiple logistic regression analysis. An overall diet quality score was calculated for each participant based on the criteria of the Dutch Healthy Diet (DHD) index. KEY RESULTS: A lower DHD-score was found for IBS (mean [SD]: 52.9 [9.6]) vs controls (55.1 [9.2], P=.02). The diet of patients was lower in fibers (21 g vs 25 g per day, P=.002) and fructose (14 g vs 16 g, P=.033), while higher in total fat (37% vs 36% of total energy intake, P=.010) and added sugars (46 g vs 44 g, P=.029). Differences in daily intake of food products included lower consumption of apples (40 g vs 69 g, P<.001), pasta (28 vs 37 g, P=.029) and alcoholic beverages (130 g vs 193 g, P=.024) and higher consumption of processed meat (38 g vs 29 g, P<.001). Some of these findings correlated with gastrointestinal symptoms, showing differences between IBS subtypes. CONCLUSIONS AND INFERENCES: Differences in habitual diet were described, showing lower diet quality in IBS patients compared to controls, with increased consumption of fat and lower intake of fibers and fructose. Our data support the importance of personalized and professional nutritional guidance of IBS patients.

Biomarkers for visceral hypersensitivity in patients with irritable bowel syndrome.

BACKGROUND: Increased visceral sensitivity is observed in up to 60% of patients with Irritable Bowel Syndrome (IBS). Mucosal inflammation, altered neuroendocrine activity and intraluminal metabolic processes may contribute to the development of visceral hypersensitivity. Previously, we demonstrated that biomarkers, indicative for these biological processes, were altered in IBS patients compared to healthy controls. However, how these processes relate to visceral hypersensitivity is unknown. AIM: The aim of this study was to provide insight in biological processes associated with visceral hypersensitivity. Fecal and plasma biomarkers were measured in normosensitive and hypersensitive IBS patients. METHODS: A total of 167 IBS patients underwent a rectal barostat procedure to assess visceral sensitivity to pain. Based on the outcome, patients were classified into a normosensitive or hypersensitive group. Calprotectin, human ß-defensin 2 (HBD2), chromogranin A (CgA), and short chain fatty acids (SCFAs) were measured in feces, citrulline in plasma, and serotonin and its main metabolite 5-hydroxyindoleacetic acid (5-HIAA) in platelet-poor plasma. KEY RESULTS: Fecal markers and plasma citrulline were measured in 83 hypersensitive and 84 normosensitive patients, while platelet-poor plasma for the assessment of serotonin and 5-HIAA was available for a subgroup, i.e. 53 hypersensitive and 42 normosensitive patients. No statistically significant differences were found in concentrations of biomarkers between groups. Adjustment of the analyses for potential confounders, such as medication use, did not alter this conclusion. CONCLUSIONS & INFERENCES: Our findings do not support a role for the biological processes as ascertained by biomarkers in visceral hypersensitivity in IBS patients. This study is registered in the US National Library of Medicine (clinicaltrials.gov, NCT00775060).

Volatile organic compounds in breath as markers for irritable bowel syndrome: a metabolomic approach.

BACKGROUND: The diagnosis of irritable bowel syndrome (IBS) is challenging because of its heterogeneity and multifactorial pathophysiology. No reliable biomarkers of IBS have been identified so far. AIMS: In a case-control study, using a novel application of breath analysis to distinguish IBS patients from healthy controls based on the analysis of volatile organic compounds (VOCs). Subsequently, the diagnostic VOC-biomarker set was correlated with self-reported gastrointestinal (GI) symptoms of subjects of the Maastricht IBS clinical cohort and of a general population cohort, LifeLines DEEP. METHODS: Breath samples were collected from 170 IBS patients and 153 healthy controls in the clinical cohort and from 1307 participants in general population cohort. Multivariate statistics were used to identify the most discriminatory set of VOCs in the clinical cohort, and to find associations between VOCs and GI symptoms in both cohorts. RESULTS: A set of 16 VOCs correctly predicted 89.4% of the IBS patients and 73.3% of the healthy controls (AUC = 0.83). The VOC-biomarker set correlated moderately with a set of GI symptoms in the clinical (r = 0.55, P = 0.0003) and general population cohorts (r = 0.54, P = 0.0004). A Kruskal-Wallis test showed no influence from possible confounding factors in distinguishing IBS patients from healthy controls. CONCLUSIONS: A set of 16 breath-based biomarkers that distinguishes IBS patients from healthy controls was identified. The VOC-biomarker set correlated significantly with GI symptoms in two independent cohorts. We demonstrate the potential use of breath analysis in the diagnosis and monitoring of IBS, and a possible application of VOC analyses in a general population cohort.

Alterations in serotonin metabolism in the irritable bowel syndrome.

BACKGROUND: Alterations in serotonin (5-HT) metabolism have been postulated to play a role in the pathogenesis of irritable bowel syndrome (IBS). However, previous reports regarding 5-HT metabolism in IBS are contradicting. AIM: To compare platelet poor plasma (PPP) 5-HT and 5-hydroxyindole acetic acid (5-HIAA) levels and their ratio in a large cohort of IBS patients and healthy controls (HC), including IBS-subgroup analysis. METHODS: Irritable bowel syndrome patients and HC were evaluated for fasting PPP 5-HT and 5-HIAA levels. Furthermore, GI-symptom diary, GSRS, quality of life, anxiety and depression scores were assessed in the 2 weeks before blood sampling. RESULTS: One hundred and fifty four IBS patients and 137 HC were included. No differences were detected in plasma 5-HT between groups. The 5-HIAA concentrations and 5-HIAA/5-HT ratio were significantly lower in IBS compared to HC: 24.6 ± 21.9 vs. 39.0 ± 29.5 µg/L (P < 0.001) and 8.4 ± 12.2 vs. 13.5 ± 16.6 (P < 0.01), respectively. Subtype analysis for 5-HIAA showed all IBS subtypes to be significantly different from HC. The 5-HIAA/5-HT ratio was significantly lower in the IBS-M subtype vs. HC. Linear regression analysis points to an influence of gender but not of GI-symptoms, psychological scores or medication use. CONCLUSIONS: We demonstrated that fasting 5-HT plasma levels are not significantly different in IBS patients compared to controls. However, decreased 5-HIAA levels and 5-HIAA/5-HT ratio in IBS patients may reflect altered serotonin metabolism in IBS. Gender affects 5-HIAA levels in IBS patients, but no effects of drugs, such as SSRIs, or higher GI-symptom or psychological scores were found.

Systematic review: instruments to assess abdominal pain in irritable bowel syndrome.

BACKGROUND: Consensus on standard methods to assess chronic abdominal pain in patients with irritable bowel syndrome (IBS) is currently lacking. AIM: To systematically review the literature with respect to instruments of measurement of chronic abdominal pain in IBS patients. METHODS: Systematic literature search was performed in PubMed/Medline databases for studies using pain measurement instruments in patients with IBS. RESULTS: One hundred and ten publications were reviewed. A multitude of different instruments is currently used to assess chronic abdominal pain in IBS patients. The single-item methods, e.g. the validated 10-point numeric rating scale (NRS), and questionnaires assessing gastrointestinal symptoms severity, focus mostly on the assessment of only the intensity of abdominal pain. Of these questionnaires, the validated IBS-Symptom Severity Scale includes the broadest measurement of pain-related aspects. General pain questionnaires and electronic momentary symptom assessment tools have been used to study abdominal pain in IBS patients, but have not yet been validated for this purpose. The evidence for the use of provocation tests, e.g. the rectal barostat with balloon distention, for measurement of abdominal pain in IBS is weak, due to the poor correlation between visceral pain thresholds assessed by provocation tests and abdominal pain as assessed by retrospective questionnaires. CONCLUSIONS: The multitude of different instruments to measure chronic abdominal pain in IBS makes it difficult to compare endpoints of published studies. There is need for validated instruments to assess chronic abdominal pain in IBS patients, that overcome the limitations of the currently available methods.

The Experience Sampling Method--a new digital tool for momentary symptom assessment in IBS: an exploratory study.

BACKGROUND: Retrospective questionnaires are frequently used for symptom assessment in irritable bowel syndrome (IBS) patients, but are influenced by recall bias and circumstantial and psychological factors. These limitations may be overcome by random, repeated, momentary assessment during the day, using electronic Experience Sampling Methodology (ESM). Therefore, we compared symptom assessment by ESM to retrospective paper questionnaires in IBS patients. METHODS: Twenty-six IBS patients (Rome III) were included, of which 16 were diagnosed with panic disorder (DSM-IV-TR). Patients scored symptoms using end-of-day diaries during 14 days and the gastrointestinal symptom rating scale (GSRS) once. ESM was used on seven consecutive days during the same time period. KEY RESULTS: End-of-day diary abdominal pain scores were 0.4 (SE 0.1, p < 0.001) point higher (on a 1-to-5-point scale) compared to corresponding ESM mean-scores in IBS patients. The difference was even more pronounced for upper abdominal pain scores assessed by the GSRS (4.77 ± 1.50) compared to ESM mean-scores (2.44 ± 1.30, p < 0.001), both on 1-to-7-point scale. For flatulence, comparable results were found. Nausea and belching scores showed small, but significant differences between end-of-day diary and ESM. All tested symptoms were scored higher on GSRS compared to ESM mean-scores (p < 0.01). Affective comorbidity did not influence differences in pain reporting between methods. CONCLUSIONS & INFERENCES: IBS patients report higher scores for abdominal pain in retrospective questionnaires compared to ESM, with a tendency to report peak rather than average pain scores. ESM can provide more insight in symptom course and potential triggers, and may lead to a better understanding of IBS symptomatology.

Markers for visceral hypersensitivity in patients with irritable bowel syndrome.

BACKGROUND: Irritable bowel syndrome (IBS) is a heterogenous disorder with visceral hypersensitivity as important hallmark. It is not known whether IBS patients with visceral hypersensitivity have different epidemiological and clinical characteristics compared with IBS patients without visceral hypersensitivity. Aim of our study was to compare in detail a large group of hyper- vs normosensitive IBS patients with respect to epidemiological and clinical characteristics. METHODS: IBS patients (Rome III criteria) have been recruited for a large-scale cohort study. All patients from this cohort who underwent a rectal barostat procedure were included and allocated based on those with and without visceral hypersensitivity. Patient demographics, and symptoms were collected using questionnaires (GSRS, HADS, SF-36) and a 14-day symptom diary for IBS-related symptoms. A multivariate logistic regression model was used to identify risk markers for having visceral hypersensitivity. KEY RESULTS: Ninety-five normosensitive and 93 hypersensitive IBS patients participated in this study. Hypersensitive patients had significantly higher scores for GSRS abdominal pain (p < 0.05), indigestion, reflux and constipation syndrome (all p < 0.01), and IBS symptom intensity, discomfort (both p < 0.05) and mean symptom composite score (p < 0.01). Age, female sex, and the use of SSRI medication were significantly different between the normo- and the hypersensitive IBS patients. However, after adjustment for other risk markers, only increasing age was found to be significantly associated with lower odds for having hypersensitivity (OR 0.97 [95% CI: 0.94; 0.99]). CONCLUSIONS & INFERENCES: Apart from more severe symptomatology, hypersensitive IBS patients are characterized by significantly younger age compared with normosensitive IBS patients. The study has been registered in the US National Library of Medicine (http://www.clinicaltrials.gov, NCT00702026).

Small intestinal permeability is increased in diarrhoea predominant IBS, while alterations in gastroduodenal permeability in all IBS subtypes are largely attributable to confounders.

BACKGROUND: Intestinal permeability has been studied in small groups of IBS patients with contrasting findings. AIMS: To assess intestinal permeability at different sites of the GI tract in different subtypes of well-characterised IBS patients and healthy controls (HC), and to assess potential confounding factors. METHODS: IBS patients and HC underwent a multi-sugar test to assess site-specific intestinal permeability. Sucrose excretion and lactulose/rhamnose ratio in 0-5 h urine indicated gastroduodenal and small intestinal permeability, respectively. Sucralose/erythritol ratio in 0-24 h and 5-24 h urine indicated whole gut and colonic permeability, respectively. Linear regression analysis was used to assess the association between IBS groups and intestinal permeability and to adjust for age, sex, BMI, anxiety or depression, smoking, alcohol intake and use of medication. RESULTS: Ninety-one IBS patients, i.e. 37% IBS-D, 23% IBS-C, 33% IBS-M and 7% IBS-U and 94 HC were enrolled. Urinary sucrose excretion was significantly increased in the total IBS group [µmol, median (Q1;Q3): 5.26 (1.82;11.03) vs. 2.44 (0.91;5.85), P < 0.05], as well as in IBS-C and IBS-D vs. HC. However, differences attenuated when adjusting for confounders. The lactulose/rhamnose ratio was increased in IBS-D vs. HC [0.023 (0.013;0.038) vs. 0.014 (0.008;0.025), P < 0.05], which remained significant after adjustment for confounders. No difference was found in 0-24 and 5-24 h sucralose/erythritol ratio between groups. CONCLUSIONS: Small intestinal permeability is increased in patients with IBS-D compared to healthy controls, irrespective of confounding factors. Adjustment for confounders is necessary when studying intestinal permeability, especially in a heterogeneous disorder such as IBS.

Detection of pleiotropic drug resistance by the rapid immunofluorescence assay of drug effects on the cell skeleton.

We describe the development of an immunofluorescent method for the detection of resistance to agents which affect the integrity of the cellular microtubular network. Three pleiotropic resistant MCF-7 human breast carcinoma cell lines mixed with vaginal adenocarcinoma cells were selected in serially increasing drug concentrations, and demonstrated a 30-fold increase in resistance to colchicine. Transport studies indicated that there was no difference in drug accumulation between the sensitive and resistant lines. The colchicine-binding capacity of cell extracts from sensitive and resistant cells was similar (Kd for sensitive cells was 1.9 x 10(-6) M and for resistant cells 1.58 x 10(-6) M). There were, however, significant differences in cytoskeletal morphology between sensitive and resistant cells. Drug-sensitive cells were mostly large (about 70 microns 2) and flattened. Their cytoplasm was filled with a microtubular network in which, in most of the cases, single fibers could be differentiated. Cells usually had a microtubule-organizing center and paracortical bundles of microtubules. In contrast, drug-resistant cells were mostly rounded and grew in clumps. In only 40% of these cells could single microtubular fibers be differentiated. Resistant cells lacked a microtubule-organizing center and had no clear paracortical bundles of microtubules. The tubulin-binding agents tested caused a sequence of morphological changes in sensitive cells. These changes included precipitation of tubulin and disappearance of cytoskeletal structure. Changes occurred initially within 3 h of incubation, but were expressed in all cells after 6 h. If, after 3 h of drug exposure, cells were subcultured in drug-free media, the cytoskeletal structure reformed within 10 h. Maximal recovery of cytoskeletal structure occurred 22 h after drug removal and was sustained up to 36 h. In contrast to changes observed in sensitive cells, drug exposure did not induce changes in the morphology of cytoskeleton in resistant cells. Cells from all three resistant lines reverted to sensitivity after 7 months of culture in drug-free media. This was first detected by immunofluorescence and then confirmed by cloning assay. Since the cytoskeletal disintegration of sensitive cells is readily detectable within a few hours of in vitro drug treatment, immunofluorescent imaging may have its clinical application in predicting the sensitivity/resistance to microtubule-binding agents.