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.