Feasibility and repeatability of ultrasound-guided surface electroenterography to measure colonic slow wave motility in healthy adults.

Surface electroenterography is a potential non-invasive alternative to current diagnostics of colonic motility disorders. However, electrode positioning in electroenterography is often based on general anatomy and may lack generalizability. Furthermore, the repeatability of electroenterography measurements is unknown. This study aimed to evaluate ultrasound-guided electrode positioning for electroenterography measurements and to determine the repeatability of those measurements. In ten healthy adults, two electroenterography procedures were performed, consisting of fasting, ultrasound-guided electrode localization and two 20-minute electroenterography recordings separated by a meal. The dominant frequency, the mean power density (magnitude of colonic motility) and the power percent difference (relative pre- to postprandial increase in magnitude) were determined. Repeatability was determined by Lin's concordance correlation coefficient. The results demonstrated that the dominant frequency did not differ between pre- and postprandial recordings and was 3 cpm, characteristic of colonic motility. The mean power density increased between the pre- and postprandial measurements, with an average difference of over 200%. The repeatability of both the dominant frequency and power density was poor to moderate, whereas the correlation coefficient of the power percent difference was poor. Concluding, ultrasound-guided surface electroenterography seems able to measure the gastrocolic reflex, but the dissatisfactory repeatability necessitates optimization of the measurement protocol.

Gastrocolic Reflex Is Delayed and Diminished in Adults with Type 1 Diabetes.

BACKGROUND: Constipation is a prevalent gastrointestinal complication in diabetes. The pathophysiology may include neural dysfunction and impaired gastrocolic reflex; however, investigation of the latter has been limited in diabetes. Using the wireless motility capsule, we investigated whether the gastrocolic reflex was impaired in adults with type 1 diabetes compared to healthy. METHODS: One hundred and four adults with type 1 diabetes underwent investigation with the wireless motility capsule and recorded sleep cycle, eating habits, and bowel movements in a diary. Colonic motility index, contraction amplitudes, time-to-peak, peak motility, and colonic transit time were investigated directly in response to a meal. Diagnosis of peripheral (nerve conduction) and autonomic (orthostatic hypotension) polyneuropathy was verified. RESULTS: In comparison with health, people with diabetes had at the time of ingestion decreased motility index and contraction amplitudes (p < 0.001), prolonged time-to-peak (p = 0.01), and borderline decreased peak motility (p = 0.06), which taken together indicate impaired coordination of the gastrocolic reflex. These features were most prominent in those with concomitant peripheral or autonomic neuropathy. Additionally, they were associated with prolonged colonic transit time (p > 0.01). CONCLUSIONS: In type 1 diabetes, the gastrocolic reflex was delayed and diminished and further associated with the presence of neuropathy and constipation. These results suggest that impaired reflex is part of the underlying pathogenesis in the development of constipation.

Diurnal changes of colonic motility and regulatory factors for colonic motility in Suncus murinus.

BACKGROUND: The aim of this study was to investigate the fundamental mechanisms of colonic motility in the house musk suncus (Suncus murinus) as an established animal model of gut motility. METHODS: To measure gut motility in free-moving conscious suncus, strain gauge force transducers were implanted on the serosa of the colon and gastric body. KEY RESULTS: We recorded diurnal changes in colonic motility and observed the relationship between feeding and colonic motility. Giant migrating contractions (GMCs) of the colon were invariably detected during defecation and tended to increase during the dark period, thereby indicating that colonic motility has a circadian rhythm. Given that GMCs in the suncus were observed immediately after feeding during the dark period, we assume the occurrence of a gastrocolic reflex in suncus, similar to that observed in humans and dogs. We also examined the factors that regulate suncus GMCs. Intravenous administration of 5-HT (100 µg/kg), substance P (10 and 100 µg/kg), calcitonin gene-related peptide (10 µg/kg), and α2 adrenergic receptor antagonist yohimbine (0.5, 1, and 3 mg/kg) induced GMC-like contractions, as did intragastric and intracolonic administration of the transient receptor potential vanilloid 1 agonist, capsaicin (1 mg/kg). CONCLUSIONS & INFERENCES: These results indicate that the fundamental mechanisms of colonic motility in suncus are similar to those in humans and dogs, and we thus propose that suncus could serve as a novel small animal model for studying colonic motility.