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Background: Colonic transit (CT) measured by validated scintigraphy using 111 In-labeled activated charcoal particles is summarized using geometric center (GC) of isotopic distribution in four colonic regions and stool at 24 and 48 h. Diagnosis of rapid CT is currently based on GC24 ≥4.4 in females and >4.7 in males, which lack sensitivity. Our aim was to evaluate, in patients with chronic diarrhea with normal CT by GC24 and GC48, the diagnostic utility of CT change (∆GC) relative to sex-matched normal values., Methods: We evaluated two adult patient cohorts: 701 clinical patients (1994-2023) with chronic diarrhea and 76 research participants with irritable bowel syndrome with diarrhea (N = 63) or bile acid diarrhea (BAD, N = 13). Results of ∆GC were compared to 220 healthy controls' 95th percentiles (%ile) (≥2.0 females and ≥2.2 males). In the research cohort, we also analyzed (Spearman correlation) colonic ∆GC with ascending colon emptying T 1/2 (AC T 1/2 ), average stool frequency and consistency based on a daily diary, total fecal bile acid (BA) concentration, and % primary BA in a single stool sample., Key Results: Among 701 clinical patients with normal GC24, 160 (22.3%) had rapid CT based on ∆GC 95th %ile in health. Among 76 research participants, an additional 20.6% IBS-D and 23% BAD had rapid CT ∆GC. Younger age and absence of diabetes mellitus were predictive of rapid ∆GC. ∆GC significantly correlated with AC T 1/2 and with fecal BA., Conclusions & Inferences: ∆GC identified an additional 21%-23% patients with rapid colonic transit among patients with diarrhea and normal GC24., (© 2024 John Wiley & Sons Ltd.)

Background/aims: There is currently no gold standard for evaluating stool burden in the colon for patients with gastrointestinal symptoms. We aim to examine the relationship between fecal loading on single view abdominal X-ray imaging and gastrointestinal symptoms such as constipation, diarrhea, bloating, and accidental bowel leakage in adult outpatients., Methods: This retrospective, cross-sectional study examined patients seen at University of Michigan from 2005 to 2017. Chart review of demographic information, reported gastrointestinal symptoms, past medical history, and abdominal radiographic imaging was performed. Bivariate analysis was performed to assess associations between these characteristics and fecal loading. Factors independently associated with fecal loading were identified using logistic regression. Significance was established at p < 0.05., Results: In total, 319 patients who had an X-ray were included in the final analysis, with 84.0% demonstrating fecal loading on the initial X-ray and most reporting constipation as a symptom (n = 214, 84.3%, p = 0.0334). In logistic regression, a chief complaint of constipation had higher odds of being associated with fecal loading on X-ray compared to diarrhea (adjusted OR 6.41; CI 1.51-27.24, p = 0.0118). Bloating as a reported symptom was statistically significant with an adjusted OR of 2.56 (CI 1.10-5.96, p = 0.0286)., Conclusions: Constipation (as a chief complaint) and bloating (as a symptom) were associated with fecal loading on X-ray imaging, while accidental bowel leakage and diarrhea were not.

Objectives: Non-invasive biomarkers which identify different mechanisms of disease in subgroups of irritable bowel syndrome (IBS) could be valuable. Our aim was to seek useful magnetic resonance imaging (MRI) parameters that could distinguish each IBS subtypes., Methods: 34 healthy volunteers (HV), 30 IBS with diarrhea (IBS-D), 16 IBS with constipation (IBS-C), and 11 IBS with mixed bowel habit (IBS-M) underwent whole-gut transit and small and large bowel volumes assessment with MRI scans from t=0 to t=360 min. Since the bowel frequency for IBS-M were similar to IBS-D, IBS-M and IBS-D were grouped together and labeled as IBS non-constipation group (IBS-nonC)., Results: Median (interquartile range): fasting small bowel water content in IBS-nonC was 21 (10-42), significantly less than HV at 44 ml (15-70), P<0.01 as was the postprandial area under the curve (AUC) P<0.01. The fasting transverse colon volumes in IBS-C were significantly larger at 253 (200-329) compared with HV, IBS-nonC whose values were 165 (117-255) and 198 (106-270) ml, respectively, P=0.02. Whole-gut transit time for IBS-C was prolonged at 69 (51-111), compared with HV at 34 (4-63) and IBS-D at 34 (17-78) h, P=0.03. Bloating score (VAS 0-10 cm) correlated with transverse colon volume at t=405 min, Spearman r=0.21, P=0.04., Conclusions: The constricted small bowel in IBS-nonC and the dilated transverse colon in IBS-C point to significant differences in underlying mechanisms of disease.

Aim: To isolate the proteins involved in pharmacologic action of senna extract (SE) from mouse gastrointestinal tract and to explore the molecular mechanism of gastrointestinal motility change induced by SE., Methods: SE was administrated to mice by different routes. Gastrointestinal motility of mice was observed using cathartic, gastrointestinal propellant movement experiments and X-ray analysis. Mouse model for gastrointestinal motility enhancement was established through continuous gastric administration of SE at progressively increased dose. At 3 h and week 3, 4, 6 and 10, morphological changes of gastrointestinal tissues were found under light microscope. Ultrastructural changes of intestinal and colonic tissues at week 6 were observed under transmission electron microscope. The colonic proteomic changes in model mice were examined by two-dimension polyacrylamide gel electrophoresis with immobilized pH gradient isoelectric focusing to screen the differentially expressed proteins, and their molecular masses and isoelectric points were determined. Two N-terminal sequences of the samples were also determined by mass spectrometry., Results: SE (0.3g) caused diarrhea after gastric administration in 1-6h and enhanced gastrointestinal propellant (65.1+/-7.5%; 45.8+/-14.6%, P<0.01) in mice, but intramuscular and hypodermic injection had no cathartic effect. X-ray analysis of gastrointestinal motility demonstrated that gastric administration of SE enhanced gastric evacuation and gastrointestinal transferring function. At 3 h and week 3 and 4 after gastric administration of SE, light microscopic examination revealed no apparent change in gastrointestinal mucosal tissues, but transmission electron microscopic examination revealed inflammatory changes in whole layer of intestinal and colonic wall. Twenty differential proteins were detected in the colonic tissues of the model mice by two-dimensional electrophoresis, and the N-terminal amino acid sequences of two proteins were determined., Conclusion: SE causes diarrhea and enhances gastrointestinal motility through digestive tract administration. Long-term gastric administration of SE induces inflammatory changes and cell damage in the whole gastrointestinal tract. The differential proteins screened from the colonic tissues of the model mice might mediate the enhancing effect of SE on gastrointestinal motility.