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

Background and aims: The pathogenesis of asymptomatic diverticular disease (ADD) and symptomatic uncomplicated diverticular disease (SUDD) has not been elucidated. The aim of our study was to assess whether altered visceral perception or abnormal compliance of the colorectal wall play a role in these clinical entities. Methods: Ten ADD patients, 11 SUDD patients, and nine healthy controls were studied. Using a dual barostat device, sensations were scored and compliance curves obtained using stepwise intermittent isobaric distensions of the rectum and sigmoid, before and after a liquid meal. In addition, the colonic response to eating was assessed by monitoring the volumes of both barostat bags at operating pressure before and after the meal. Results: In the rectum, perception was increased in the SUDD group compared with controls (p=0.010) and the ADD group (p=0.030). Rectal compliance curves were not different between the groups. In the sigmoid colon, perception in the pre- and postprandial periods was increased in SUDD compared with controls (p = 0.018) but not when compared with ADD. Sigmoid volume-pressure curves had comparable slopes (compliance) in all groups but were shifted downwards in SUDD compared with ADD in the preprandial period (p=0.026). The colonic response to eating (decrease in intrabag volume) was similar in all three groups, both in the rectum and sigmoid. Conclusion: Symptomatic but not asymptomatic uncomplicated diverticular disease is associated with heightened perception of distension, not only in the diverticula bearing sigmoid, but also in the unaffected rectum. This hyperperception is not due to altered wall compliance. [ABSTRACT FROM AUTHOR]

Abstract The purpose of this study was to develop a computer program for fully automated analysis of all presently known motor patterns in human colonic motility recordings. Colonic pressure recordings obtained from 24 healthy volunteers were used. Algorithms were developed for the detection and numerical analysis of five types of pressure waves: antegrade, retrograde, simultaneous, high-amplitude and isolated pressure waves. Furthermore, periodical motor activity was quantified. Validation was performed by comparison with visual analysis by two experienced observers. Patterns recorded during day- and night-time were compared using multiple-factor analysis of variance with Bonferroni correction. Automated analysis correlated well with visual peak detection (r = 0.98, P <0.01) and detection of antegrade pressure waves (r = 0.98, P <0.01). Most motor patterns showed a diurnal variation. During the night, prevalences of antegrade ( 938 vs 455; P <0.05), retrograde (112 vs 81; P <0.05), high-amplitude (12.9 vs 1.3; P <0.05), isolated pressure waves (1114 vs 765; P <0.05), and periodic motor activity were decreased (7.33 vs 4.47%; P <0.05). However, when expressed as percentage of absolute numbers of pressure waves, prevalences remained constant. In conclusion, fully automated analysis of all hitherto described colonic motility patterns is feasible. During the night, overall wave prevalences markedly decreased, but the distribution over the various motor patterns was preserved. [ABSTRACT FROM AUTHOR]

Background: Alosetron is a 5-hydroxytryptamine-3 receptor antagonist reducing symptoms in female patients with diarrhoea-predominant irritable bowel syndrome, and is known to increase the colonic transit time. Aim: To study the effect of alosetron on left colonic phasic motility in ambulant non-constipated patients with irritable bowel syndrome and healthy volunteers. Methods: In a double-blind, randomized, crossover design, 10 patients with irritable bowel syndrome and 12 sex- and age-matched volunteers were treated for two 7-day periods with alosetron, 4 mg b.d., or placebo b.d. On day 6 of each treatment period, a six-channel solid-state manometric catheter was positioned in the left colon and 24 h motility was studied on day 7. The periprandial phasic motility around dinnertime was evaluated in the descending and sigmoid colon. The high-amplitude propagated contraction frequency and characteristics were calculated. Results: Alosetron appeared to increase the overall periprandial frequency in the sigmoid colon (P =0.043) and the mean amplitude of colonic contractions in the descending colon (P =0.007). The high-amplitude propagated contraction frequency was higher on alosetron during the second half of the day for patients with irritable bowel syndrome (P =0.002), with increased mean propagation length of high-amplitude propagated contractions (P =0.001). The stool frequency (P =0.024) and stool consistency score (P =0.002) were decreased by alosetron. Conclusions: The 5-hydroxytryptamine-3 receptor antagonist alosetron marginally increased left colonic periprandial phasic motility. Alosetron increased the number and propagation length of high-amplitude propagated contractions, which were paradoxically accompanied by a decrease in stool frequency and a firming of stool consistency. [ABSTRACT FROM AUTHOR]