The "Biology-First" Hypothesis: Functional disorders may begin and end with biology-A scoping review

While it is generally accepted that gastrointestinal infections can cause functional disturbances in the upper and lower gastrointestinal tract-known as postinfectious irritable bowel syndrome (PI-IBS) and functional dyspepsia (PI-FD)-it has still not been widely recognized that such an infection can also initiate functional non-intestinal diseases, and that non-intestinal infections can provoke both intestinal and non-intestinal functional disturbances. We conducted a scoping review of the respective literature and-on the basis of these data-hypothesize that medically unexplained functional symptoms and syndromes following an infection may have a biological (genetic, endocrine, microbiological) origin, and that psychological and social factors, which may contribute to the disease "phenotype," are secondary to this biological cause. If this holds true, then the search for psychological and social theories and factors to explain why one patient develops a chronic functional disorder while another does not is-at least for postinfectious states-misleading and detracts from exploring and identifying the true origins of these essentially biological disorders. The biopsychosocial model may, as the term implies, always begin with biology, also for functional (somatoform) disorders.

A fresh look at IBS-opportunities for systems medicine approaches

NeuroGUT is a EU-funded initial training network (ITN) of 14 research projects in neurogastroenterology that have employed an equal number of early-stage researchers. Neurogut trainees have-among other activities-attended an international conference on irritable bowel syndrome (IBS) in Bologna in 2016 and were asked to critically review and evaluate the current knowledge on IBS for their respective research activities, and to state what they were missing. Most appreciated were the topics brain imaging of gut activity, the role of the gut microbiota, the pharmacology of gut functions, the IBS-IBD interrelation, the new Rome IV criteria, the role of gas, and the placebo response in functional disorders. Missed were more detailed coverage of high-resolution manometry, functional brain imaging, advanced "systems medicine" approaches and bioinformatics technology, better sub-classification of IBS patients, and the development of disease biomarkers, extended at the molecular (genetic/epigenetic, proteonomic) level. They summarize that despite excellent specialized research, there is a gap open that should be filled with systems medicine. For this, it would be necessary that medical research learns even more from the data sciences and other basic disciplines, for example, information technology and system biology, and also welcomes a change in paradigm that enhances open sharing of data, information, and resources.

Gastric ghrelin, GOAT, leptin, and leptinR expression as well as peripheral serotonin are dysregulated in humans with obesity

BACKGROUND

Gastrointestinal hormone release and the regulation of appetite and body weight are thought to be dysbalanced in obesity. However, human data investigating the expression of gastrointestinal hormones in the obese are rare. We studied the expression of ghrelin, leptin, and the serotonergic system in stomach tissue and serum of obese and non-obese individuals.

METHODS

Gastric tissue and serum were collected from 29 adult obese (BMI 48.7 ± 10.6 kg/m(2) ; mean ± SD) who underwent laparoscopic sleeve gastrectomy. Gastric biopsies, surgery specimen or serum was obtained from 35 adult non-obese humans (BMI 22.7 ± 1.9 kg/m(2) ). Ghrelin, ghrelin O-acyl transferase (GOAT), leptin, leptin receptor, and tryptophan hydroxylase 1 (TPH1) mRNA expression were measured by qRT-PCR. Serotonin (5HT) and leptin protein concentration were quantified in tissue extracts and serum; GOAT and ghrelin-positive cells were immunohistologically quantified in tissue. Additionally, 21 blood immune markers were analyzed.

KEY RESULTS

In gastric tissue, GOAT-positive cells were reduced (p < 0.01), but ghrelin-positive cells and mRNA were increased (both p < 0.05) in obese compared with non-obese individuals. Gastric leptin (p < 0.001) and leptin receptor (p < 0.001) mRNA expression, as well as leptin concentrations in serum (p < 0.001), were increased in obese compared with non-obese individuals. Serum 5HT was reduced (p < 0.05), while tissue 5HT and TPH1 mRNA were reduced only by trend. Interleukin 1 receptor a (IL1Ra), IL-8, IL-12, and monocyte chemoattractant protein 1 (IL1Ra) were increased and IL1Ra correlated negatively with serum leptin.

CONCLUSIONS & INFERENCES

Our data indicate that obesity causes a dysregulation of gastrointestinal hormones at the tissue level and serum, including a negative correlation with an increased marker of subclinical inflammation.

Functional neuroimaging studies in functional dyspepsia patients: a systematic review

BACKGROUND

There is increasing evidence in support of the presence of abnormal central changes (compared to healthy controls) in functional dyspepsia (FD) in addition to the peripheral changes in gastrointestinal tract.

PURPOSE

This systematic review aims to provide an integrative understanding of the abnormal functional brain activity, visceral sensation, dyspeptic symptoms, and psychological changes of FD. Electronic and hand searches were conducted to identify functional neuroimaging studies involving FD patients. Sixteen studies were selected and divided into three categories: 10 resting state studies, three visceral distention studies, and three acupuncture studies. Changes were reported in several brain areas in FD patients including the frontal cortex, somatosensory cortex, insula, anterior cingulate cortex, thalamus, hippocampus, and amygdala. These brain activity changes were associated with visceral hypersensitivity, dyspeptic symptoms, poorer quality of life, anxiety, and depression. The results show that FD is associated with functional abnormalities in sensory and pain modulation, emotion, saliency, and homeostatic processing regions. The diversity of conditions, heterogeneous results, poorly standardized diagnoses of FD, and various comorbidities may be responsible for the variability in the results.

Postinfectious irritable bowel syndrome after travelers' diarrhea--a cohort study

BACKGROUND

There is sound evidence for the role of gastrointestinal infections in the development of postinfectious irritable bowel syndrome (PI-IBS), but understanding the interaction between mental factors and the infection remains incomplete. This study aims to (i) assess the occurrence of PI-IBS in a cohort of patients with self-reported travelers' diarrhea (TD), (ii) assess risk factors for PI-IBS development, and (iii) investigate the prognosis of PI-IBS after 1 year.

METHODS

Patients consulting the travel clinic at the University Hospital Tuebingen, Germany (in 2009 and 2010) were identified from records and questioned in follow-ups in 2011 and 2012. We used the Rome III modular questionnaire to assess IBS, the Hospital Anxiety and Depression Scale to assess anxiety and depression, and the Patient Health Questionnaire to assess somatization.

KEY RESULTS

We identified 529 eligible subjects from the clinical records. Of 135 subjects (age: 36.6 ± 14.6 years, 58.5% female) included in the study sample 6.7% (95% CI 3.0-11.1) had PI-IBS. We found more females (88.9% vs 56.3%, p = 0.08) and younger age subjects (mean 29.3 vs 37.1 years, p = 0.02) among the PI-IBS subjects. A multivariable regression model revealed vomiting at baseline and high somatization scores as strong and independent PI-IBS risk factors. One year later PI-IBS occurrence decreased to 3.3% (three cases of 90).

CONCLUSIONS & INFERENCES

Our findings underline the close linkage of mental and somatic processes for the manifestation of PI-IBS. Screening for psychiatric comorbidities in patients with severe gastrointestinal infections may allow identifying groups at high risk for PI-IBS.

Systematic review with meta-analysis: post-infectious irritable bowel syndrome after travellers' diarrhoea

BACKGROUND

Gastrointestinal infection is known as a risk factor for the development of the irritable bowel syndrome (post-infectious irritable bowel syndrome, PI-IBS). The incidence of PI-IBS ranges between 3% and over 30% of people after infectious gastroenteritis.

AIM

To perform a meta-analysis pools and report data concerning the relative risk (RR) of PI-IBS after TD.

METHODS

Database search using Medline through PubMed, Scopus, EBM Reviews (Cochrane Database of Systematic Reviews) and PsycINFO was performed to identify relevant studies. Those that met the inclusion criteria were pooled. A random effects model (Mantel-Haenszel) was performed.

RESULTS

Six eligible studies were found. In three of six studies, the authors reported a statistically significant association of TD and PI-IBS. The pooled RR was 3.35 (95% CI: 2.22-5.05) with a significant overall effect (P < 0.00001). Overall PI-IBS incidence was 5.4% in TD subjects and 1.4% in healthy subjects. There was no significant heterogeneity within the pooled studies (I(2)  = 5%). Self-reported TD alone resulted in an over 1.5-fold RR for PI-IBS compared to laboratory-confirmed TD [RR 3.90 (95% CI: 2.35-6.49) vs. RR 2.42 (95% CI: 1.22-4.78)].

CONCLUSIONS

There is a strong association between travellers' diarrhoea and post-infectious irritable bowel syndrome. Self-reports of exposure seem to result in a higher post-infectious irritable bowel syndrome occurrence than laboratory-confirmed cases of travellers' diarrhoea, but further studies are needed to confirm this finding. Finally, potential influences of the selection of an appropriate study population on post-infectious irritable bowel syndrome epidemiology are discussed.

Review article: Associations between Helicobacter pylori and obesity--an ecological study

BACKGROUND

There is emerging debate over the effect of Helicobacter pylori infection on body mass index (BMI). A recent study demonstrated that individuals who underwent H. pylori eradication developed significant weight gain as compared to subjects with untreated H. pylori colonisation.

AIM

To elucidate the association between H. pylori colonisation and the prevalence of overweight and obesity in developed countries.

METHODS

The literature was searched for publications reporting data on H. pylori prevalence rates and obesity prevalence rates. Studies selected reported H. pylori prevalence in random population samples with sample sizes of more than 100 subjects in developed countries (GDP >25,000 US$/person/year). Corresponding BMI distributions for corresponding countries and regions were identified. Nonparametric tests were used to compare the association between H. pylori and overweight and obesity rates.

RESULTS

Forty-nine studies with data from 10 European countries, Japan, the US and Australia were identified. The mean H. pylori rate was 44.1% (range 17-75%), the mean rates for obesity and overweight were 46.6 (± 16)% and 14.2 (± 8.9)%. The rate of obesity and overweight were inversely and significantly (r = 0.29, P < 0.001) correlated with the prevalence of H. pylori infection.

CONCLUSIONS

There is an inverse correlation between H. pylori prevalence and rate of overweight/obesity in countries of the developed world. Thus, the gradual decrease of the H. pylori colonisation that has been observed in recent decades (or factors associated with decrease of) could be causally related to the obesity endemic observed in the Western world.

Perception and pain thresholds for cutaneous heat and cold, and rectal distension: associations and disassociations

BACKGROUND

Hypersensitivity to somatic or visceral pain has been reported in numerous clinical conditions such as fibromyalgia or the irritable bowel syndrome, and general hypersensitivity has been proposed to be the underlying mechanism. However, cross-modal relationships especially between somatic and visceral pain have rarely been investigated even in healthy volunteers. Furthermore, psychological influences on pain have rarely been characterized across modalities.

METHODS

Sixty-one healthy participants underwent testing of perception and pain thresholds for cutaneous thermode heat and cold, as well as for rectal balloon distension. Psychological testing for anxiety, depression, and pain experience (including catastrophizing and coping) as well as cardiac interoception was performed. Measurement quality and the correlations between the different modalities were examined.

KEY RESULTS

Significant correlations existed between the perception thresholds for cold/heat (τB  = -0.28, p = 0.002) and cold/distension (τB  = -0.21, p = 0.03) and for the pain thresholds for cold/heat (r = -0.61, p < 0.001) and heat/distension (r = 0.33, p = 0.01). No association was found between pain thresholds and anxiety, depression, psychological experience with and processing of pain, or cardiac interoception. Retest reliabilities for pain measurements were satisfying after short intertrial intervals (all intraclass correlation coefficients >0.8), but less so after longer intervals. The individuals contributing to the respective correlations differ between measurements.

CONCLUSIONS & INFERENCES

Moderate associations were found for pain thresholds across modalities. The strength of the associations and their stability over time warrants further investigation and might serve to increase the understanding of conditions affecting multiple pain modalities.

Heart rate variability in the irritable bowel syndrome: a review of the literature

BACKGROUND

Patients with irritable bowel syndrome (IBS) often present with disturbances of bowel habits (diarrhea, constipation) and abdominal pain/discomfort that are modulated by the autonomic nerve system (ANS). In this narrative review, we analyzed studies that measured ANS functioning in IBS by means of heart rate variability (HRV).

METHODS

The PUBMED was searched with the keywords 'irritable bowel syndrome' AND ('heart rate variability' OR 'autonomic function'). We included only papers that used 'traditional' HRV indices and diagnosed IBS based on Manning or Rome criteria. Studies were sub-grouped according to methodological features of HRV analysis (24-h monitoring, short-term laboratory records, records during sleep).

KEY RESULTS

Most studies reported no difference in HRV when the IBS population was compared to healthy controls. Dividing the IBS sample into subgroups--according to their predominant bowel symptoms, the severity of clinical course, the presence of depressive symptoms, or a history of abuse in the past--revealed changes in autonomic functioning.

CONCLUSIONS & INFERENCES

Patients with IBS appear to experience symptoms that may be the result of changes in ANS functioning. HRV measures in clinical routine may allow assessing these changes, but further studies performed in a standardized fashion should improve the validity of HRV measures for clinical research first.

Heart rate variability in anorexia nervosa and the irritable bowel syndrome

BACKGROUND

Many studies have reported disturbances of heart rate variability (HRV) in patients with psychosomatic disorders such as anorexia nervosa (AN) and the irritable bowel syndrome (IBS). However, both have never been directly compared.

METHODS

We compared HRV in AN (n = 21) and in IBS (n = 21) (all females) with 42 healthy female control subjects who were matched for age and in IBS to body mass index (BMI). Recovery periods between different cardiac load tests were compared with baseline recordings and tilt test to estimate time [mean successive difference (MSD)] and frequency domain (Goldberger dimension, frequency of HF peak location and HF power, log HF power) values and to assess general reactivity of the autonomic nervous system (ANS).

KEY RESULTS

Significantly longer inter-beat intervals (IBIs) in AN patients and lower values of MSD in IBS patients were found in comparison with respective controls; both were independent from experimental conditions and are found in baseline recordings only. Both effects were independent of age and BMI. We also demonstrate a significant relationship between age, BMI and some HRV parameters.

CONCLUSIONS & INFERENCES

Opposite autonomic patterns were found in AN and IBS: stronger vagal withdrawal in IBS and weaker vagal inhibition in AN patients. Records made at rest and without any autonomic load may be representative for assessment of ANS function. Age and BMI should be taken into consideration during assessment of HRV data.

Postinfectious irritable bowel syndrome: follow-up of a patient cohort of confirmed cases of bacterial infection with Salmonella or Campylobacter

BACKGROUND

Gastrointestinal infections have been proposed to predict subsequent irritable bowel syndrome (IBS) but large-scale infectious events are rare and long-term data are missing.

METHODS

We identified 576 individuals with a Salmonella or Campylobacter infection between 2000 and 2009 that were followed by a short postal questionnaire asking for the presence of current symptoms in 2010. In case of agreement (n = 90), an extended postinfectious (PI)-IBS questionnaire was mailed including the Hospital Anxiety Depression Scale and the Patient Health Questionnaire.

KEY RESULTS

A total of 189 patients reported back (36%); 98 had a Salmonella and 91 had a Campylobacter infection, of which 56 reported persistent symptoms (9.7% of the initial sample). Fifty-one patients returned the PI-IBS questionnaire. Of 48 patients with complete data, 15 reported no or mild symptoms of abdominal pain or discomfort while 17 had moderate and 16 severe symptoms. Twenty-two met Rome IBS criteria, 14 (29%) reported GI symptoms before the infection. Patients with moderate and/or severe PI-IBS symptoms were significantly more often females, were more often infected by Salmonella than by Campylobacter, had more severe symptoms during the initial infection, and had more often GI symptoms prior to the infection. They reported higher anxiety, depression, and somatisation scores, but were not different with respect to acute stool habits.

CONCLUSIONS & INFERENCES

Nearly 10% of patients with an intestinal bacterial infection report postinfectious symptoms up to 10 years after the infectious event. They represent a clinically important population with high psychiatric comorbidity and somatic symptom burden.

A vegan or vegetarian diet substantially alters the human colonic faecal microbiota

BACKGROUND/OBJECTIVES

Consisting of ≈10(14) microbial cells, the intestinal microbiota represents the largest and the most complex microbial community inhabiting the human body. However, the influence of regular diets on the microbiota is widely unknown.

SUBJECTS/METHODS

We examined faecal samples of vegetarians (n=144), vegans (n=105) and an equal number of control subjects consuming ordinary omnivorous diet who were matched for age and gender. We used classical bacteriological isolation, identification and enumeration of the main anaerobic and aerobic bacterial genera and computed absolute and relative numbers that were compared between groups.

RESULTS

Total counts of Bacteroides spp., Bifidobacterium spp., Escherichia coli and Enterobacteriaceae spp. were significantly lower (P=0.001, P=0.002, P=0.006 and P=0.008, respectively) in vegan samples than in controls, whereas others (E. coli biovars, Klebsiella spp., Enterobacter spp., other Enterobacteriaceae, Enterococcus spp., Lactobacillus spp., Citrobacter spp. and Clostridium spp.) were not. Subjects on a vegetarian diet ranked between vegans and controls. The total microbial count did not differ between the groups. In addition, subjects on a vegan or vegetarian diet showed significantly (P=0.0001) lower stool pH than did controls, and stool pH and counts of E. coli and Enterobacteriaceae were significantly correlated across all subgroups.

CONCLUSIONS

Maintaining a strict vegan or vegetarian diet results in a significant shift in the microbiota while total cell numbers remain unaltered.

A vegan or vegetarian diet substantially alters the human colonic faecal microbiota

BACKGROUND/OBJECTIVES

Consisting of ≈10(14) microbial cells, the intestinal microbiota represents the largest and the most complex microbial community inhabiting the human body. However, the influence of regular diets on the microbiota is widely unknown.

SUBJECTS/METHODS

We examined faecal samples of vegetarians (n=144), vegans (n=105) and an equal number of control subjects consuming ordinary omnivorous diet who were matched for age and gender. We used classical bacteriological isolation, identification and enumeration of the main anaerobic and aerobic bacterial genera and computed absolute and relative numbers that were compared between groups.

RESULTS

Total counts of Bacteroides spp., Bifidobacterium spp., Escherichia coli and Enterobacteriaceae spp. were significantly lower (P=0.001, P=0.002, P=0.006 and P=0.008, respectively) in vegan samples than in controls, whereas others (E. coli biovars, Klebsiella spp., Enterobacter spp., other Enterobacteriaceae, Enterococcus spp., Lactobacillus spp., Citrobacter spp. and Clostridium spp.) were not. Subjects on a vegetarian diet ranked between vegans and controls. The total microbial count did not differ between the groups. In addition, subjects on a vegan or vegetarian diet showed significantly (P=0.0001) lower stool pH than did controls, and stool pH and counts of E. coli and Enterobacteriaceae were significantly correlated across all subgroups.

CONCLUSIONS

Maintaining a strict vegan or vegetarian diet results in a significant shift in the microbiota while total cell numbers remain unaltered.

Post-infectious irritable bowel syndrome--a review of the literature

INTRODUCTION

Despite considerable research efforts, the epidemiological characteristics of post-infectious symptoms of the irritable bowel syndrome-type (PI-IBS) are not yet well defined. Estimates of its incidence after gastrointestinal (GI) infection show considerable variation and the number of patients with a history of a GI infection among all patients with IBS is practically unknown. This review aims at summarizing published estimates (i) on the prevalence of PI-IBS among all IBS patients and (ii) on PI-IBS incidence after GI infection, critically discusses methodological differences that may explain the variation of the presented findings and gives an overview on currently identified risk factors for the development of PI-IBS.

METHODS

A systematic literature review was perfomed of studies indexed in PUBMED that assessed the epidemiology and risk factors of PI-IBS.

RESULTS

The reported incidence of PI-IBS ranges for epidemic infections between 7 and 36 %, for individual infections between 4 and 36 % and for traveller's diarrhea from 4 to 14 %. Estimates of the prevalence of PI-IBS range from as low as 7 % to more than ⅓ of all IBS patients, depending on the study design. The predictors and biomarkers are varying among the studies.

CONCLUSION

PI-IBS appears to be common following infectious enteritis and among all IBS patients, but precise estimates are still lacking.

[Probiotic therapy of the irritable bowel syndrome]

The irritable bowel syndrome (IBS) is among the most common disorders in gastroenterological practice with a prevalence of approx. 12 % in Germany, and it is characterized by abdominal pain or discomfort, altered stool frequency and consistency, and meteorism and bloating. There is currently no agreement between those seeing patients with IBS (general practitioner, gastroenterologist, psychosomatics) on the criteria for clinical diagnosis. Metaanalyses of treatment studies in IBS have shown that probiotics have a high clinical efficacy in IBS, especially since development of novel pharmaceutical compounds have not reached the market or have been withdrawn. In addition to the actual status of probiotic efficacy in IBS studies conducted worldwide, we present 3 German clinical studies with probiotic E.COLI preparations that have proven their efficacy in IBS in adults and in children.

Acute tryptophan depletion increases experimental nausea but also induces hunger in healthy female subjects

BACKGROUND

Acute tryptophan depletion (ATD) is an experimental model to reduce central serotonin levels.

METHODS

Thirty-eight healthy female subjects were randomly assigned to two groups (ATD and control) in a randomized, double-blinded parallel-group design. Following a standardized and balanced amino acid diet (including 1.21 g tryptophan) on the first day, they received either a protein drink without tryptophan (but substituted by other amino acids) (ATD condition) or the balanced protein drink with tryptophan (control condition) 24 h later. Four hours after its consumption, they were exposed to a standard rotation procedure. Symptom ratings (SR), ratings of hunger and mood scores were taken prior to rotation, at each break, and 15 and 30 min thereafter, together with saliva cortisol samples.

KEY RESULTS

Five subjects could not tolerate the entire rotation procedure and were excluded from analysis. For the remaining n = 33, SR and hunger ratings were higher during ATD than during control conditions, but mood was unaffected. Cortisol levels rose significantly with rotation but were unaffected by ATD. High baseline cortisol levels were associated with lower SR during rotation. The protective effects of morning cortisol were pronounced during the menstrual and follicular phase of the cycle and not present during ovulation and the luteal phase.

CONCLUSIONS & INFERENCES

Acute tryptophan depletion is associated with increased symptoms of nausea in healthy female subjects when exposed to body rotation. Acute tryptophan depletion also increases hunger rating. These opposite effects may indicate independent actions of the serotonin on central and peripheral functions.

Affective disturbances modulate the neural processing of visceral pain stimuli in irritable bowel syndrome: an fMRI study

OBJECTIVE

To address the role of anxiety and depression symptoms in altered pain processing in irritable bowel syndrome (IBS).

DESIGN

In this functional magnetic resonance imaging study, the blood oxygen level-dependent (BOLD) response to rectal distensions delivered at previously determined individual discomfort thresholds was assessed.

PATIENTS

15 female patients with irritable bowel syndrome (IBS) and with normal rectal pain thresholds, and 12 healthy women.

MEASURES

The correlation of anxiety and depression symptoms, measured with the Hospital Anxiety and Depression Scale (HADS), with subjective pain ratings and the BOLD response during distension-induced brain activation were analysed within IBS. Group differences in pain-induced brain activation with and without controlling for HADS scores were evaluated.

RESULTS

Patients with IBS experienced significantly more pain and discomfort upon rectal distensions in the scanner, despite unaltered rectal sensory thresholds. Anxiety and depression scores were associated with these subjective stimulus ratings, but not with rectal sensory thresholds. Anxiety symptoms in IBS were significantly associated with pain-induced activation of the anterior midcingulate cortex and pregenual anterior cingulate cortex. Depression scores correlated with activation of the prefrontal cortex (PFC) and cerebellar areas within IBS. Group comparisons with the two-sample t test revealed significant activation in the IBS versus controls contrast in the anterior insular cortex and PFC. Inclusion of anxiety and depression scores, respectively, as confounding variables led to a loss of significant group differences.

CONCLUSIONS

Altered central processing of visceral stimuli in IBS is at least in part mediated by symptoms of anxiety and depression, which may modulate the affective-motivational aspects of the pain response.

Probiotic treatment of irritable bowel syndrome in children

Treatment of functional bowel disorders of irritable bowel-type (IBS) in children remains a difficult task because of a lack of drugs with low adverse event profile. We here report the results of a treatment study in 203 children (66 boys and 137 girls) age 4 to 18 years (mean: 10.5+/-4.5 years) with typical IBS symptoms with abdominal pain and either predominant diarrhea (n=50), constipation (n=56), alternating stool frequency (n=28) or unspecific pain (n=69). The average duration of symptoms prior to therapy was 175 days. Most (95%) patients up to age 11 were treated with a daily dose of 10 drops of Symbioflor 2 (SF2) (SymbioPharm, Herborn) (cells and autolysate of 1.5-4.5x10(7) CFU of bacteria of Escherichia coli type), in the elder children 77% received this dosage, while the remaining received a higher dose up to 30 drops/day. Treatment lasted 43 days on average.

RESULTS

All patients tolerated the treatment well and without adverse events. The key IBS symptoms (abdominal pain, stool frequency) as well as the other symptoms (bloating, mucous and blood in stool, need for straining at stools, urge to defecate) improved significantly during treatment. Global assessment of therapy by parents and doctors was altogether positive. In summary these data confirm efficacy and tolerability of this probiotic compound in children and adolescents and supplement published data of probiotic IBS therapy in adults.

[Hypnotherapy for irritable bowel syndrome--a systematic review]

The Irritable bowel syndrome (IBS) is a highly prevalent functional disorder with a remarkable clinical and economic impact. Several pathogenetic factors of IBS are discussed and summarised within a bio-psycho-social model. Data from published hypnotherapeutic interventions with approximately 800 patients show long-lasting symptom relief. The underlying mechanisms of action are not well understood. Nine mechanism studies show influences of hypnosis on colorectal sensitivity, colorectal motility and mental strain (anxiety, depression, maladaptive cognitions). Results are often contradictory and effects of hypnosis on several of the proposed pathogenetic factors are not examined at all. This paper reviews previous studies on hypnotherapy in IBS patients with a focus on symptom relief and mechanisms of action.

Biofeedback therapy in fecal incontinence and constipation

We examine the collected evidence for efficacy of biofeedback therapy (BFT) in incontinence and constipation by means of meta-analysis of randomized controlled trials. PubMed search was performed to identify treatment trials that match quality criteria (adequate control groups, randomization). They were entered into meta-analyses using fixed effect models and computing odds ratio (OR) and 95% confidence interval (CI) of treatment effects. For constipation, eight BFT trials were identified. In four trials, electromyographic (EMG) BFT was compared to non-BFT treatments (laxatives, placebo, sham training and botox injection), while in the remaining four studies EMG BFT was compared to other BFT (balloon pressure, verbal feedback) modes. Meta-analyses revealed superiority of BFT to non-BFT (OR: 3.657; 95% CI: 2.127-6.290, P < 0.001) but equal efficacy of EMG BFT to other BF applications (OR: 1.436; CI: 0.692-3.089; P = 0.319). For fecal incontinence, a total of 11 trials were identified, of which six compared BFT to other treatment options (sensory training, pelvic floor exercise and electrical stimulation) and five compared one BFT option to other modalities of BFT. BFT was equal effective than non-BFT therapy (OR: 1.189, CI: 0.689-2.051, P = 0.535). No difference was found when various modes BFT were compared (OR: 1.278, CI: 0.736-2.220, P = 0.384). Included trials showed a substantial lack of quality and harmonization, e.g. variable endpoints and missing psychological assessment across studies. BFT for pelvic floor dyssynergia shows substantial specific therapeutic effect while BFT for incontinence is still lacking evidence for efficacy. However, in both conditions the mode of BFT seems to play a minor role.

The effects of ageing on the colonic bacterial microflora in adults

BACKGROUND

The composition of the fecal mircoflora and its changes on ageing have rarely been investigated in large samples of both patients and volunteers.

METHODS

We analysed the fecal flora by conventional microbiological testing (Kyberstatus, Institute of Microecology, Herborn, Germany) of stool samples from 35 292 adults (age: 46.3 +/- 0.08 [18 to 96] years, 9564 males, 24 784 females; remaining = missing data) with different intestinal and non-intestinal diagnoses for total colony-forming units (CFU) (per g stool) as well as relative abundance of Bifidobacteria, Bacteroides spp., Escherichia coli, Enterococcus spp., and Lactobacillus spp. with respect to age, gender, and clinical data available (e. g., stool consistency and pH).

RESULTS

The total CFU was stable and showed no age- or gender-related changes. Individual bacterial species constantly and significantly increased with age (E. coli, Enterococci spp.), or decreased at higher age (Bacteroides spp.), or were stable throughout the life span (Lactobacilli, Bifidobacteria). Gastrointestinal diagnoses (Crohn's disease, n = 198; ulcerative colitis, n = 515; irritable bowel syndrome, n = 7765; other GI diagnoses, n = 10 478) tended to exhibit some specificity of the bacterial profile, and when GI diagnoses were excluded, the age-related bacterial profile of the remaining group (n = 15 619, m:f = 4197:11 422) was not different.

CONCLUSION

Conventional microbiological investigations of the fecal microbiota showed both bacteria-specific as well as a general pattern of ageing of the colonic microbiota, with the last decades (more than 60 years) demonstrating the most profound changes. It remains to be shown whether these changes reflect direct changes of the gut microbiota, the mucosal innate immunity, or indirect consequences of age-related altered nutrition.

The placebo response in functional dyspepsia--reanalysis of trial data

Clinical trial data rarely identify factors contributing to the placebo response. We reanalysed the data from the placebo arm (n = 157) of a functional dyspepsia (FD) trial to determine predictors of placebo response including total GIS score, change in GIS score during run-in, type of FD symptoms, duration of illness, age, gender, body mass index (BMI), family occurrence of FD-like symptoms, smoking and alcohol consumption. The same response criteria were applied to the drug arm (n = 158) of the study. Based on the initial 40% response criterion of the study, 35 (22.2%) were classified as placebo responders (PR), whilst 122 (78.8%) were placebo non-responders (PnR). Response rates for the drug arm were 41.1 and 56.9% respectively. PR had significantly lower GIS scores compared to PnR at visit 1 (10.6 +/- 0.6 and 12.3 +/- 0.4, respectively, P = 0.035), but not at visit 2 with study medication dispensing (10.9 +/- 0.5 and 11.3 +/- 0.4). Hence, PR symptoms increased during run-in by 4.2% whilst PnR symptoms decreased by 6.3% (P < 0.005). Gender, age and duration and type of FD symptoms were not different between PR and PnR. Smoking was less prevalent in PR (3%) compared to PnR (21%) (P < 0.025). Increasing the criteria for the placebo response resulted in higher BMI for PR than for PnR (P = 0.035). None of the predictors for placebo response were able to distinguish responders from non-responders to the drug. Variables predicting the PR point towards behavioural and biological mechanism of the PR, operating simultaneously and independently.

The story of O--is oxytocin the mediator of the placebo response?

While the placebo responses in various medical conditions have been shown to follow a few basic principles such as expectancies, reward learning and Pavlovian conditioning, the underlying neurobiology and the mediating hormonal and/or neuromodulating processing have remained obscure. We here report the collected evidence that oxytocin (OXT), a 389-amino acid polypeptide located on chromosome 3p25 that is released in the brain (hypothalamus) and in peripheral tissue, is the central mediator of the placebo response: we hypothesize that exogenous OXT via an OXT agonist will enhance the placebo response, while exogenous OXT blockade by an antagonist will reduce the placebo response in placebo analgesia and other placebo models. It is furthermore proposed that the placebo response in trials may be predicted by circulating plasma OXT levels, the OXT receptor density in the brain and/or the presence of one or more of the single nucleotide polymorphisms of the OXT promoter gene.

Cortisol levels predict motion sickness tolerance in women but not in men

A variety of intrinsic and extrinsic factors contribute to motion sickness severity in a stressful motion environment. The interplay of all these factors may partially explain the high inter-subject variability of motion sickness susceptibility found in many studies as well as some of the contradictory findings between studies regarding the modulating influence of single factors. We investigated the role of endogenous cortisol levels, gender and repetitive experience for motion sickness susceptibility. Motion sickness was induced in 32 healthy, but motion-sickness susceptible volunteers (16:16 males:females), by means of a vection drum. Subjects were investigated between 8:00 am (high cortisol) and 11:00 am (low cortisol), and on five consecutive days. Tolerance to rotation (RT) of the drum, motion sickness symptom ratings (SR) and salivary cortisol levels were assessed. Baseline cortisol levels correlated positively with RT in women, but not in men. RT showed a gender-specific time course across days, with higher values in males than in females on day 1, and sensitization on day 3 only in men. SR and cortisol levels following rotation did not differ between males and females, or between testing days. Gender differences in motion sickness susceptibility appear to be linked to a different role of basal cortisol levels for motion sickness tolerance. Results clearly indicate the need to control for gender, day time and cortisol levels in studies of motion sickness.

Randomized controlled treatment trial of irritable bowel syndrome with a probiotic E.-coli preparation (DSM17252) compared to placebo

BACKGROUND

Therapy trials with bacterial compounds in irritable bowel syndrome (IBS) have produced conflicting results and, so far, an E.-coli preparation has not been used.

METHODS

Two hundred and ninety-eight patients with lower abdominal symptoms diagnosed as IBS were treated for 8 weeks by the compound Symbioflor-2 (Symbiopharm GmbH, Herborn, Germany), an Escherichia coli product (N = 148), or placebo (n = 150) in a double-blinded, randomized fashion. Patients were seen weekly by the physician, who assessed the presence of core IBS symptoms. Both an abdominal pain score (APS) as well as a general symptom score (GSS) were used as primary endpoints. Responders had to have complete absence of IBS core symptoms at > or = 1 visit during treatment.

RESULTS

The responder rate in GSS to the drug was 27 / 148 (18.2 %) in comparison to placebo with 7 / 150 (4.67 %) (p = 0.000397). The improvement in APS was 28 / 148 (18.9 %) and 10 / 150 (6.67 %) for placebo (p = 0.001649). The response was reached from visit 3 onwards with both medication and placebo. Post-hoc analysis revealed no significant differences in efficacy of the drug between the gender and different age groups.

CONCLUSION

Treatment of IBS with the probiotic Symbioflor-2 is effective and superior to placebo in reducing typical symptoms of IBS patients seen by general practitioners and by gastroenterologists.

Circadian variation of rectal sensitivity and gastrointestinal peptides in healthy volunteers

The aim of our study was to identify diurnal variation of perception of rectal distension and the release of gastroenteropancreatic hormones. In 12 healthy male volunteers (25 years, range 22-32), a rectal balloon distension was performed. Rectal perception thresholds (minimal, urge and pain) and rectal compliance were double-measured with a computer-controlled barostat at seven standardized time points during the day (from 16.00 to 14.00 hours the following day). Blood samples were taken 30 min before and after each rectal distension procedure to determine plasma levels of cholecystokinin (CCK), pancreatic polypeptide (PP) and motilin. Sensory thresholds for urge and pain varied significantly with the time of day, with higher threshold levels in the evening than in the morning hours. Bowel wall compliance showed as well-significant variance at pain threshold and was higher during daytime than in the evening or at night. In contrast to motilin, release of CCK and PP also showed a significant variation depending on daytime. Perception of rectal distension stimuli as well as compliance was independent of intake of food and peptide hormone levels, but CCK and PP levels increased with food, and PP levels decreased with rectal distension. Significant differences in the perception of rectal distension stimuli for urge and pain depending on daytime were found, but the release of gastrointestinal peptides seemed not to be involved. This circadian variation needs to be taken into account in patients and volunteer studies.

A mixture of Escherichia coli (DSM 17252) and Enterococcus faecalis (DSM 16440) for treatment of the irritable bowel syndrome--a randomized controlled trial with primary care physicians

Therapy trials with bacterial compounds in irritable bowel syndrome (IBS) have produced conflicting results. This study was performed in 1988 and 1989, and was re-analysed according to current IBS standards. Two hundred ninety-seven patients with lower abdominal symptoms diagnosed as IBS were treated for 8 weeks by the compound ProSymbioflor((R)) (Symbiopharm GmbH, Herborn, Germany), an autolysate of cells and cell fragments of Enterococcus faecalis and Escherichia coli, or placebo in a double-blinded, randomized fashion. Patients were seen weekly by the physician, who assessed the presence of core IBS symptoms. Responders had at least a 50% decrease in global symptom score (GSS) and in abdominal pain score (APS) reports at >/=1 visit during treatment. The responder rate in GSS to the drug was 102/149 (68.5%) in comparison to placebo with 56/148 (37.8%) (P < 0.001), the improvement in APS was 108/149 (72.5%) and 66/148 (44.6%) respectively (P = 0.001). The number-needed-to-treat was 3.27 for GSS and 3.59 for the APS report. Kaplan-Meier analysis revealed a mean response time of 4-5 weeks for active treatment and more than 8 weeks for placebo (P < 0.0001). Treatment of IBS with the bacterial lysate ProSymbioflor is effective and superior to placebo in reducing typical symptoms of IBS patients seen by general practitioners.

Cortical processing of residual ano-rectal sensation in patients with spinal cord injury: an fMRI study

Eleven paraplegic patients with complete traumatic spinal cord injuries (SCI) [according to American Spinal Injury Association (ASIA) criteria] at different levels (Th3-L3) were investigated during non-painful stimulation of the distal rectum and anal canal, using event related functional magnetic resonance imaging. Although a complete lesion was clinically diagnosed in all, four of them experienced reproducible sensations during anal and/or rectal stimulation. In six patients, individual data analysis revealed significant activation in the right secondary somatosensory cortex SII, the posterior cingular gyrus, the prefrontal cortex, and the left posterior cerebellar lobe during either anal or rectal stimulation or both. A Region of interest analysis using a data mask from healthy controls confirmed that SCI patients demonstrate cortical activation in areas similar to those activated in healthy volunteers, but to a less extensive degree. This supports the notion that the diagnosis of complete spinal cord transsection by ASIA criteria alone may be insufficient for assessment of 'completeness' of cord lesions, and that visceral sensitivity testing may be required in addition.

[The next consensus for the irritable bowel syndrome has to be interdisciplinary]

The publication of the Rome III consensus on functional bowel disorders one year ago has raised the question of whether a revision of the 1999 Celle consensus on the irritable bowel syndrome is necessary and who should be involved in this consensus. Therefore, the this review article attempts to reconstruct the history of the Rome criteria (and its predecessor, the Manning criteria) and contrasts this with the parallel history of the DSM/ICD classification in primary care and psychiatry/psychosomatics. The formulation of a common consensus between all medical societies (primary care, gastroenterology/neurogastroenterology, psychiatry/psychosomatics) is proposed instead of another consensus of gastroenterologists alone, in order to avoid the tendency--at both national and international levels--towards isolation between the medical subspecialties.

Empfehlungen zur Anorektalen Manometrie im Erwachsenenalter

This document contains the guidelines of the German Societies of Neurogastroenterology and Motility, Gastroenterology (committee for proctology), Abdominal Surgery (coloproctology working group), and Coloproctology for anorectal manometry in adults. Recommendations are given about technical notes, study preparation (equipment; patient), technique for performing manometry and data analysis, reproducibility, and indications. Minimum standards for anorectal manometry are measurement of resting and squeeze pressure, testing of rectoanal inhibitory reflex, determination of rectal sensation (first perception and urge), and calculation of rectal compliance. Anorectal manometry is indicated in patients with fecal incontinence and constipation in the context of a structured programme.

Digestive und prädigestive Funktionen bei Patienten mit Essstörungen

Patients with eating disorders (anorexia nervosa, AN; bulimia nervosa, BN) frequently exhibit gastrointestinal symptoms and altered gastrointestinal functions, especially delayed gastric emptying. These symptoms are regarded as secondary to the disordered eating behaviour, vomiting or laxative misuse. They often improve during successful therapy. There are, however, studies showing that in addition predigestive functions (smell, taste, cephalic phase of digestion) and the hormonal regulation of digestion may be changed in eating disorders. This underlines the possibility that, in a subpopulation of patients with AN and BN, the disturbed digestive and predigestive functions may be involved in the pathogenesis of the eating disorders. The current literature is analysed and summarised in this context.

Neuroendocrinological effects of acupuncture treatment in patients with irritable bowel syndrome

OBJECTIVES

Quality of life (QoL) improvement in patients with irritable bowel syndrome (IBS) during acupuncture (AC) treatment seems to be due to a placebo effect. The aim was to explore if acupuncture has some specific influence on the neuroendocrinic and autonomic nervous system (ANS).

DESIGN/SETTING

Patients with IBS were randomly assigned to receive either acupuncture (AC) or sham acupuncture (SAC) using the so-called "Streitberger needle". QoL was measured with the functional quality of life diseases quality of life questionnaire (FDDQL) and SF-36. The effect on ANS was evaluated by measuring salivary cortisol and by cardiovascular responses on a tilt table before and after 10 AC treatments. Complete data sets of tilt table and salivary morning cortisol were available for 9 patients in the AC and 12 in SAC group.

RESULTS

QoL increased in both groups (p=0.001) with no group differences. Salivary cortisol decreased in all groups (F=10.55; p=0.006). However, the decrease was more pronounced in the AC group (F=4.07; p=0.033) (ANOVA repeated measures model). Heart rate response decreased during orthostatic stress in the AC group while it increased in the SAC group (F=9.234; p=0.005), indicating an increased parasympathetic tone in the AC group. Improvement of pain was positively associated with increased parasympathetic tone in the AC group (F=10.1; p=0.006), but not in the SAC group.

CONCLUSIONS

The acupuncture specific physiological effects are in contrast to the unspecific improvement of QoL in both AC and SAC groups. Thus, different mechanisms seem to be involved in placebo and real-acupuncture driven improvements. The specific mechanism of action of acupuncture on the ANS remains unclear and deserves further evaluation.