Approach to Disorders of Gut-Brain Interaction

Short- and long-term reproducibility of body surface gastric mapping using the Gastric Alimetry® system

BACKGROUND

Many diagnostic tests for gastroduodenal symptoms, such as gastric emptying scintigraphy (GES), gastric emptying breath tests (GEBT), and electrogastrography (EGG) show variable intra-individual reproducibility over time. This study investigated the short- and long-term reproducibility of body surface gastric mapping (BSGM), a non-invasive test for assessing gastric function, in controls and patients with chronic gastroduodenal disorders.

METHODS

Participants completed three standardized BSGM tests using Gastric Alimetry® (Alimetry, New Zealand). The test encompassed a fasting baseline (30 min), a 482 kCal standard meal, and a 4 h postprandial recording. The first two tests were >6 months apart and the last occurred ~1 week after the second test, to evaluate long and short-term reproducibility.

RESULTS

Fourteen patients with upper gastrointestinal symptoms and 14 healthy controls were recruited. There were no significant differences in any BSGM metrics between the tests at short and long term (all p > 0.180). Lin's concordance correlation coefficients (CCC) for the primary metrics were high, ranging from 0.58 to 0.96, with intra-individual coefficients of variance (CVintra) ranging from 0.2% to 1.9%. Reproducibility was higher, and intra-individual variation lower, than in previous studies of GES (CCC = 0.54-0.83, CVintra = 3%-77%), GEBT (CVintra = 8%-11%), and EGG (CVintra = 3%-78%).

CONCLUSIONS

BSGM spectral metrics demonstrate high reproducibility and low intra-individual variation at both short and long term, with superior results to comparable tests. The high reproducibility of Gastric Alimetry supports its role as a diagnostic aid for gastric dysfunction and a reliable tool for evaluating treatment outcomes and disease progression over time.

Clostridioides difficile infection promotes gastrointestinal dysfunction in human and mice post-acute phase of the disease

OBJECTIVES

In the US, Clostridioides difficile (C. difficile) infection (CDI) is the 8th leading cause of hospital readmission and 7th for mortality among all gastrointestinal (GI) disorders. Here, we investigated GI dysfunction post-CDI in humans and mice post-acute infection.

MATERIALS AND METHODS

From March 2020 to July 2021, we reviewed the clinical records of 67 patients referred to the UVA Complicated C. difficile clinic for fecal microbiota transplantation (FMT) eligibility. C57BL/6 mice were infected with C. difficile and clinical scores were determined daily. Stool samples from mice were collected to measure the shedding of C. difficile and myeloperoxidase (MPO) levels. On day 21 post-infection, Evans's blue and FITC-70kDa methods were performed to evaluate GI motility in mice.

RESULTS

Of the 67 patients evaluated at the C. difficile clinic, 40 patients (59.7%) were confirmed to have CDI, and 22 patients (32.8%) with post-CDI IBS (diarrhea-type, constipation-type, and mixed-type). In infected mice, levels of MPO in stools and clinical score were higher on day 3. On day 21, mice recovered from body weight loss induced by CDI, and fecal MPO was undetectable. The total GI transit time (TGITT) and FITC-70kDa levels on the proximal colon were increased in infected mice (p = 0.002), suggesting a constipation phenotype post-acute phase of CDI. A positive correlation intestinal inflammation on day 3 and TGITT on day 21 was observed.

CONCLUSION

In conclusion, post-infection intestinal dysfunction occurs in humans and mice post-CDI. Importantly, we have validated in the mouse model that CDI causes abnormal GI transit in the recovery phase of the disease, indicating the potential utility of the model in exploring the underlying mechanisms of post-infectious IBS in humans.

The impact of running on gastrointestinal symptoms in patients with irritable bowel syndrome

INTRODUCTION

Physical activity has been suggested to alleviate gastrointestinal (GI) symptoms in patients with irritable bowel syndrome (IBS); however, evidence is scarce. Running has become increasingly popular and may be beneficial for patients with IBS. To obtain more insight in the potential application of running as therapy, we aimed to explore the impact of running and its intensity on GI symptoms in patients with IBS.

METHODS

Data from a large observational study in runners were used for this nested case-control study, which included 153 runners with IBS and 153 controls. All participants had completed a questionnaire on personal characteristics, running characteristics and GI symptoms. Regarding GI symptoms, the severity of nine symptoms was asked, both at rest and during and/or shortly (up to 3 h) after running. Each symptom could be scored on a scale from 0 (not bothersome) to 100 (very bothersome), resulting in a maximum total score of 900 points.

KEY RESULTS

The prevalence and total severity score of GI symptoms were higher in runners with IBS than in controls, both at rest and during running. Among runners with IBS, the median (25th-75th percentile) total severity score during/after running was significantly lower than at rest (118 [50-200] vs. 150 [90-217]), while in controls no significant difference between running and rest was observed. Analyses stratified for running intensity revealed that the beneficial effect in runners with IBS was present when their most intensive training session was moderately intensive or intensive but not very intensive.

CONCLUSIONS & INFERENCES

Running, particularly on moderate intensity, could have a beneficial effect on GI symptoms in patients with IBS.

Effects of Cirsium palustre Extracts and Their Main Flavonoids on Colon Motility-An Ex Vivo Study

For centuries, various species from the genus Cirsium have been utilized in traditional medicine worldwide. A number of ethnopharmacological reports have pointed out that Cirsium plants can be applied to diminish digestive problems. Among them, Cirsium palustre (L.) Scop. (Asteraceae) stands out as a promising herbal drug candidate because its constituents exhibit antimicrobial and antioxidant potential, as evidenced by ethnopharmacological reports. As a result, the species is particularly intriguing as an adjunctive therapy for functional gastrointestinal and motility disorders. Our research goal was to verify how the extracts, fractions, and main flavonoids of C. palustre affect colon contractility under ex vivo conditions. An alternative model with porcine-isolated colon specimens was used to identify the effects of C. palustre preparations and their primary flavonoids. LC-ESI-MS was utilized to evaluate the impacts of methanol (CP1), methanolic 50% (CP2), and aqueous (CP3) extracts as well as diethyl ether (CP4), ethyl acetate (CP5), and n-butanol (CP6) fractions. Additionally, the impacts of four flavonoids, apigenin (API), luteolin (LUT), apigenin 7-O-glucuronide (A7GLC), and chrysoeriol (CHRY), on spontaneous and acetylcholine-induced motility were assessed under isometric conditions. The results showed that C. palustre extracts, fractions, and their flavonoids exhibit potent motility-regulating effects on colonic smooth muscle. The motility-regulating effect was observed on spontaneous and acetylcholine-induced contractility. All extracts and fractions exhibited an enhancement of the spontaneous contractility of colonic smooth muscle. For acetylcholine-induced activity, CP1, CP2, and CP4 caused a spasmolytic effect, and CP5 and CP6 had a spasmodic effect. LUT and CHRY showed a spasmolytic effect in the case of spontaneous and acetylcholine-induced activity. In contrast, API and A7GLC showed a contractile effect in the case of spontaneous and pharmacologically induced activity. Considering the results obtained from the study, C. palustre could potentially provide benefits in the treatment of functional gastrointestinal disorders characterized by hypomotility and hypermotility.

Parieto-occipital ERP indicators of gut mechanosensation in humans

Understanding the neural processes governing the human gut-brain connection has been challenging due to the inaccessibility of the body's interior. Here, we investigated neural responses to gastrointestinal sensation using a minimally invasive mechanosensory probe by quantifying brain, stomach, and perceptual responses following the ingestion of a vibrating capsule. Participants successfully perceived capsule stimulation under two vibration conditions (normal and enhanced), as evidenced by above chance accuracy scores. Perceptual accuracy improved significantly during the enhanced relative to normal stimulation, which was associated with faster stimulation detection and reduced reaction time variability. Capsule stimulation induced late neural responses in parieto-occipital electrodes near the midline. Moreover, these 'gastric evoked potentials' showed intensity-dependent increases in amplitude and were significantly correlated with perceptual accuracy. Our results replicated in a separate experiment, and abdominal X-ray imaging localized most capsule stimulations to the gastroduodenal segments. Combined with our prior observation that a Bayesian model is capable of estimating computational parameters of gut-brain mechanosensation, these findings highlight a unique form of enterically-focused sensory monitoring within the human brain, with implications for understanding gut feelings and gut-brain interactions in healthy and clinical populations.