Hans Törnblom

Self-Reported Food-Related Gastrointestinal Symptoms in IBS Are Common and Associated With More Severe Symptoms and Reduced Quality of Life

OBJECTIVES:Despite the fact that food and diet are central issues, that concern patients with irritable bowel syndrome (IBS), the current understanding about the association between the intake of certain foods/food groups and the gastrointestinal (GI) symptom pattern, psychological symptoms, and quality of life is poor. The aim of this study was to determine which food groups and specific food items IBS patients report causing GI symptoms, and to investigate the association with GI and psychological symptoms and quality of life.METHODS:We included 197 IBS patients (mean age 35 (18–72) years; 142 female subjects) who completed a food questionnaire in which they specified symptoms from 56 different food items or food groups relevant to food intolerance/allergy. The patients also completed questionnaires to assess depression and general anxiety (Hospital Anxiety and Depression), GI-specific anxiety (Visceral Sensitivity Index), IBS symptoms (IBS-Severity Scoring System), somatic symptoms (Patient Health Questionnaire-15), and quality of life (Irritable Bowel Syndrome Quality of Life Questionnaire).RESULTS:In all, 84% of the studied population reported symptoms related to at least one of the food items surveyed. Symptoms related to intake of food items with incompletely absorbed carbohydrates were noted in 138 (70%) patients; the most common were dairy products (49%), beans/lentils (36%), apple (28%), flour (24%), and plum (23%). Of these, 58% experienced GI symptoms from foods rich in biogenic amines, such as wine/beer (31%), salami (22%), and cheese (20%). Histamine-releasing foods, such as milk (43%), wine/beer (31%), and pork (21%), were also considered causes of symptoms in IBS patients. GI symptoms were also frequently reported after intake of fried and fatty foods (52%). With increasing IBS symptom severity, patients reported more food items responsible for their GI symptoms (P=0.004), and this was also found in patients with more severe somatic symptoms (P<0.0001). Women tended to report more food items causing symptoms than men (P=0.06). A high number of food items causing GI symptoms was also associated with reduced quality of life and this was significant for the following domains: sleep (r=−0.25; P=0.001), energy (r=−0.21; P=0.005), food (r=−0.29; P<0.001), social functioning (r=−0.23; P=0.001), and physical status (r=−0.16; P<0.05). However, the number of food items reported to provoke GI symptoms was unrelated to body mass index, age, IBS subtype, anxiety, depression, or GI-specific anxiety.CONCLUSIONS:The majority of IBS patients believe that certain food items are important triggers of their GI symptoms. This is especially true for foods containing carbohydrates and fat, and also may be relevant for histamine-releasing food items and foods rich in biogenic amines. Self-reported food intolerance is associated with high symptom burden and reduced quality of life.

Full-thickness biopsy findings in chronic intestinal pseudo-obstruction and enteric dysmotility

Background and Aims: Small bowel manometry is increasingly used in the clinical investigation of patients with symptoms of intestinal motor dysfunction. Enteric dysmotility (ED) has been suggested as a new diagnostic term for patients with abnormal intestinal motor activity but no radiological signs of chronic intestinal pseudo-obstruction (CIP). Histopathological features of adult patients with ED and CIP have been compared in a large case series to study differences and similarities between the two diagnostic groups. Methods: Routine staining and an extensive panel of immunohistochemical stains on transversal and tangential cuts from full-thickness biopsies of the small bowel were used. Results: 39 females and 11 males with CIP and 58 females and 7 males with ED were investigated. The underlying lesion was more often a visceral myopathy (22% vs 5%) or neuromyopathy (30% vs 12%) in patients with CIP than in those with ED, whereas the predominant lesion in ED was neuropathy with inflammation. Conclusion: CIP in adults is associated with very different underlying pathology, whereas ED is more homogeneously associated with neuropathy in the enteric nervous system. Neuropathy of enteric ganglia with inflammation seems to be the most common cause for measurable disturbances of intestinal motor function.

The relation between symptom improvement and gastric emptying in the treatment of diabetic and idiopathic gastroparesis

OBJECTIVES:The relationship between symptom improvement (SI) and acceleration of gastric emptying (GE) for different drugs used in the treatment of idiopathic and diabetic gastroparesis is uncertain. In this paper we examined the study-specific correlations between SI and GE, and we performed a meta-regression analysis of the association across multiple studies.METHODS:The MEDLINE database (1,946 to present) was searched, and only controlled trials or trials with an established effective comparator that compared both SI and GE were included.RESULTS:Studies were identified for metoclopramide (n=6), domperidone (n=6), cisapride (n=14), erythromycin (n=3), botulinum toxin (n=2), and levosulpiride (n=3). Even though most drugs concomitantly improved symptoms and accelerated GE, no study reported a significant correlation between SI and GE. Moreover, a correlation analysis over all studies using meta-regression did not show a significant relationship between SI and GE. Our findings need to be qualified by inconsistencies in study methods, which is a limitation but also suggests that our findings are robust to methodological factors.CONCLUSIONS:In this review, no evidence of a relationship between SI and GE was identified for different drugs used for the treatment of gastroparesis. This finding questions the use of GE measurement to direct drug development for gastroparesis.

Crosstalk at the mucosal border: importance of the gut microenvironment in IBS

The aetiology and pathology of IBS, a functional bowel disorder thought to lack an organic cause, is largely unknown. However, studies suggest that various features, such as altered composition of the gut microbiota, together with increased intestinal permeability, a changed balance in the enteroendocrine system and a dysregulated immune system in the gut, most likely have an important role in IBS. Exactly how these entities act together and give rise to symptoms is still unknown, but an altered gut microbiota composition could lead to dysregulation of the intestinal barrier as well as the enteroendocrine and the immune systems, which (through interactions with the nervous system) might generate symptoms. This Review highlights the crosstalk between the gut microbiota, the enteroendocrine system, the immune system and the role of intestinal permeability in patients with IBS.

Increased colonic bile acid exposure: a relevant factor for symptoms and treatment in IBS

Objective Bile acids may play a role in the pathogenesis of IBS. We investigated the potential effects of bile acids entering the colon and its role in the symptom pattern in IBS. Design We measured 75Se-labelled homocholic acid-taurine (75SeHCAT) retention, and serum levels of 7α-hydroxy-4-cholesten-3-one (C4) and fibroblast growth factor (FGF) 19 in patients with IBS (n=141) and control subjects (75SeHCAT n=29; C4 and FGF19 n=435). In patients with IBS stool frequency and form, as well as GI symptom severity were registered, and in a proportion of patients colonic transit time and rectal sensitivity were measured (n=66). An 8-week open-label treatment with colestipol was offered to patients with 75SeHCAT <20%, and the effect of treatment was evaluated with IBS severity scoring system and adequate relief of IBS symptoms. Results Compared with controls, patients with IBS had lower 75SeHCAT values (p=0.005), higher C4c levels (C4 corrected for cholesterol) (p<0.001), but similar FGF19 levels. Abnormal 75SeHCAT retention (<10%) was seen in 18% of patients, whereas 23% had elevated C4c levels. Patients with IBS with 75SeHCAT retention <10% had more frequent stools, accelerated colonic transit time, rectal hyposensitivity, a higher body mass index, higher C4c and lower FGF19 levels. Colestipol treatment improved IBS symptoms (IBS severity scoring system 220±109 vs 277±106; p<0.01), and 15/27 patients fulfilled criteria for treatment response (adequate relief ≥50% of weeks 5–8). Conclusions Increased colonic bile acid exposure influences bowel habit and colonic transit time in patients with IBS. A high response rate to open label treatment with colestipol supports this, but placebo-controlled studies are warranted.

Germline Genetic Contributions to Risk for Esophageal Adenocarcinoma, Barrett’s Esophagus, and Gastroesophageal Reflux

BACKGROUND Esophageal adenocarcinoma (EA) is an increasingly common cancer with poor survival. Barretts esophagus (BE) is the main precursor to EA, and every year 0.12% to 0.5% of BE patients progress to EA. BE typically arises on a background of chronic gastroesophageal reflux (GERD), one of the risk factors for EA. METHODS We used genome-wide association data to investigate the genetic architecture underlying GERD, BE, and EA. We applied a method to estimate the variance explained (array heritability, h(2)g) and the genetic correlation (rg) between GERD, BE, and EA by considering all single nucleotide polymorphisms (SNPs) simultaneously. We also estimated the polygenic overlap between GERD, BE, and EA using a prediction approach. All tests were two-sided, except in the case of variance-explained estimation where one-sided tests were used. RESULTS We estimated a statistically significant genetic variance explained for BE (h(2)g = 35%; standard error [SE] = 6%; one-sided P = 1 × 10(-9)) and for EA (h(2)g = 25 %; SE = 5%; one-sided P = 2 × 10(-7)). The genetic correlation between BE and EA was found to be high (rg = 1.0; SE = 0.37). We also estimated a statistically significant polygenic overlap between BE and EA (one-sided P = 1 × 10(-6)), which suggests, together with the high genetic correlation, that shared genes underlie the development of BE and EA. Conversely, no statistically significant results were obtained for GERD. CONCLUSIONS We have demonstrated that risk to BE and EA is influenced by many germline genetic variants of small effect and that shared polygenic effects contribute to risk of these two diseases.

Identification of an Intestinal Microbiota Signature Associated With Severity of Irritable Bowel Syndrome

BACKGROUND & AIMS We have limited knowledge about the association between the composition of the intestinal microbiota and clinical features of irritable bowel syndrome (IBS). We collected information on the fecal and mucosa-associated microbiota of patients with IBS and evaluated whether these were associated with symptoms. METHODS We collected fecal and mucosal samples from adult patients who met the Rome III criteria for IBS at a secondary/tertiary care outpatient clinics in Sweden, as well as from healthy subjects. The exploratory set comprised 149 subjects (110 with IBS and 39 healthy subjects); 232 fecal samples and 59 mucosal biopsy samples were collected and analyzed by 16S ribosomal RNA targeted pyrosequencing. The validation set comprised 46 subjects (29 with IBS and 17 healthy subjects); 46 fecal samples, but no mucosal samples, were collected and analyzed. For each subject, we measured exhaled H2 and CH4, oro-anal transit time, and the severity of psychological and gastrointestinal symptoms. Fecal methanogens were measured by quantitative polymerase chain reaction. Numerical ecology analyses and a machine learning procedure were used to analyze the data. RESULTS Fecal microbiota showed covariation with mucosal adherent microbiota. By using classic approaches, we found no differences in fecal microbiota abundance or composition between patients with IBS vs healthy patients. A machine learning procedure, a computational statistical technique, allowed us to reduce the 16S ribosomal RNA data complexity into a microbial signature for severe IBS, consisting of 90 bacterial operational taxonomic units. We confirmed the robustness of the intestinal microbial signature for severe IBS in the validation set. The signature was able to discriminate between patients with severe symptoms, patients with mild/moderate symptoms, and healthy subjects. By using this intestinal microbiota signature, we found IBS symptom severity to be associated negatively with microbial richness, exhaled CH4, presence of methanogens, and enterotypes enriched with Clostridiales or Prevotella species. This microbiota signature could not be explained by differences in diet or use of medications. CONCLUSIONS In analyzing fecal and mucosal microbiota from patients with IBS and healthy individuals, we identified an intestinal microbiota profile that is associated with the severity of IBS symptoms. TRIAL REGISTRATION NUMBER NCT01252550.

Exploring the genetics of irritable bowel syndrome: a GWA study in the general population and replication in multinational case-control cohorts

Objective IBS shows genetic predisposition, but adequately powered gene-hunting efforts have been scarce so far. We sought to identify true IBS genetic risk factors by means of genome-wide association (GWA) and independent replication studies. Design We conducted a GWA study (GWAS) of IBS in a general population sample of 11 326 Swedish twins. IBS cases (N=534) and asymptomatic controls (N=4932) were identified based on questionnaire data. Suggestive association signals were followed-up in 3511 individuals from six case-control cohorts. We sought genotype-gene expression correlations through single nucleotide polymorphism (SNP)-expression quantitative trait loci interactions testing, and performed in silico prediction of gene function. We compared candidate gene expression by real-time qPCR in rectal mucosal biopsies of patients with IBS and controls. Results One locus at 7p22.1, which includes the genes KDELR2 (KDEL endoplasmic reticulum protein retention receptor 2) and GRID2IP (glutamate receptor, ionotropic, delta 2 (Grid2) interacting protein), showed consistent IBS risk effects in the index GWAS and all replication cohorts and reached p=9.31×10−6 in a meta-analysis of all datasets. Several SNPs in this region are associated with cis effects on KDELR2 expression, and a trend for increased mucosal KDLER2 mRNA expression was observed in IBS cases compared with controls. Conclusions Our results demonstrate that general population-based studies combined with analyses of patient cohorts provide good opportunities for gene discovery in IBS. The 7p22.1 and other risk signals detected in this study constitute a good starting platform for hypothesis testing in future functional investigations.

In Functional Dyspepsia, Hypersensitivity to Postprandial Distention Correlates With Meal-Related Symptom Severity

BACKGROUND & AIMS Hypersensitivity to gastric distention, an important feature of functional dyspepsia, is assessed by stepwise balloon distention of the proximal stomach in fasting patients. However, symptoms of functional dyspepsia are often worse after a meal, so studies of postprandial balloon distentions might be more relevant. We compared the effects of fasting and postprandial stomach distention in patients with functional dyspepsia. METHODS Twenty healthy controls and 62 patients with functional dyspepsia participated in a gastric barostat study at Leuven University Hospital with graded isobaric distentions before and after a liquid meal. On a separate day, all patients underwent a gastric emptying breath test with assessment of postprandial severity of 6 different dyspeptic symptoms scored at 15-minute intervals for 4 hours. For each symptom, a meal-related severity score was obtained by adding all scores; the cumulative symptom score (CSS) was obtained by adding individual symptom severity scores. RESULTS In patients, but not in controls, postprandial sensitivity to balloon distention was significantly greater than fasting sensitivity. The CSS and individual symptom scores did not differ between patients with normal or hypersensitivity to fasting distention, but patients who were hypersensitive to postprandial distention had a significantly higher CSS, along with scores for postprandial fullness, bloating, and nausea (all P < .05). On multivariate analysis, hypersensitivity to postprandial distention was associated with hypersensitivity to fasting distention and with impaired accommodation to a meal. CONCLUSIONS Postprandial, but not fasting, distention thresholds are related to the severity of meal-related symptoms in patients with functional dyspepsia.

Clinical features and long-term survival in chronic intestinal pseudo-obstruction and enteric dysmotility

Objective. Chronic intestinal pseudo-obstruction (CIP) is the most severe form of intestinal dysmotility. Enteric dysmotility (ED) has been proposed as a new diagnostic label for patients with disturbed intestinal motility and severe symptoms but no radiological signs of pseudo-obstruction. The purpose of this study was to compare the clinical features, small-bowel manometry findings and long-term survival in patients with CIP and ED. Material and methods. Data collected during a 16-year period from 1987 to 2002 were retrospectively analysed and followed-up through 2007 in a tertiary referral centre. The study comprised 55 patients (41 F, median age 42 years, range 23–76) with CIP and 70 patients (63 F, median age 39 years, range 18–71) with ED. Results. The median observation time was 9.9 years (range 5.2–20.1). Nineteen patients with CIP (35%) and 9 patients with ED (13%) died. Survival among patients with ED was significantly better (p<0.05). Patients with CIP (49%) needed parenteral nutrition more often than patients with ED (14%). Small-bowel manometry showed similar abnormalities in the two groups but absence of a fed motor response to meals was seen in 16/43 patients with CIP compared to none with ED (p<0.001), sustained periods of uncoordinated phasic activity were more common (p<0.05) in CIP patients (23/45) than in ED patients (19/70) and severe hypomotility was only seen in 7 patients with CIP. Conclusions. CIP and ED differ with respect to severity of measurable physiological derangement, nutritional needs and long-term prognosis. Our findings indicate that CIP and ED are different entities that require different approaches to management.