Got the Munchies for an Egg Sandwich? The Effects of Cannabis on Bowel Motility and Beyond

The use of medicinal cannabis has a long history dating back thousands of years. Recent discoveries have shed light on its mechanism of action with the identification of cannabinoid receptors and endocannabinoids, which make up the body's endocannabinoid system. Cannabinoid receptors, particularly the cannabinoid 1 and 2 receptors, play a crucial role in modulating the gut-brain axis and serve as potential therapeutic targets for gastrointestinal motility and inflammatory disorders. With increasing legalization of cannabis and a rising number of users, understanding the effects of cannabis on gut motility is essential for nuclear medicine providers. Although tetrahydrocannabinol, the principal psychoactive constituent of cannabis, may decrease gut motility in experimental settings, it appears to paradoxically improve symptoms in gastroparesis. Treatment effects are difficult to measure given the large number of variables that could significantly alter outcomes, such as cannabinoid type, potency, and route of intake. Another consideration is the highly personalized gut microbiome, which directly interacts with the endocannabinoid system. Further research is required to delineate these multifaceted, complex cannabinoid interactions. The goal of this article is to explore the knowns and unknowns of the impact of cannabis on the alimentary system.

MRI tagging of colonic chyme mixing in healthy subjects: Inter-observer variability and reliability of the measurement with time

BACKGROUND

Magnetic resonance imaging (MRI) tagging techniques have been applied to the GI tract to assess bowel contractions and content mixing. We aimed to evaluate the dependence of a tagging measurement (for assessing chyme mixing) on inter-observer variability in both the ascending colon (AC) and descending colon (DC) and to investigate the temporal variation and hence reliability of the colonic tagging technique by acquiring multiple measurements over time on healthy participants.

METHODS

Two independent datasets of healthy adults were used for the retrospective inter-observer variability (Study 1: 13 datasets and Study 2: 31 datasets), and ten participants were scanned for the prospective temporal variation study following a 1 L mannitol oral preparation. All colonic tagging data were acquired on 3 T MRI scanners. The mean and the standard deviation (SD) maps were generated pixel-by-pixel using custom-written software in MATLAB. The colonic regions of interest were defined using MIPAV software. Bland-Altman plots and scatter plots were used for the inter-observer variability. The mean and SD of all repeated measures for each subject were calculated along with a one-way ANOVA to test for variations with time.

RESULTS

Scatter plots and Bland-Altman plots showed a large range of data with low variation and small limits of agreements (<5% CoV). The intraclass correlation coefficient of inter-rater reliability was excellent and 0.97 or above for the AC and DC measurements for both datasets. The temporal variation study shows that there was no significant difference found between the multiple measures with time (p = 0.53, one-way repeated measures ANOVA test).

CONCLUSIONS

MRI tagging technique can provide an assessment of colonic chyme mixing. The inter-observer study data showed high inter-rater agreement. The temporal variation study showed some individual variations with time suggesting multiple measurements may be needed to increase accuracy.

Effect of senna glycoside on serum potassium levels among patients on maintenance hemodialysis: A randomized controlled trial

BACKGROUND

Hyperkalemia is common among end-stage renal disease (ESRD) patients, and consequently contributes to an increased risk of cardiac arrhythmia. Senna glycoside may decrease colonic transit time and potassium colonic reabsorption.

METHODS

Patients on hemodialysis were randomized to receive either oral senna glycoside (n = 37) or control (n = 36) for 8 weeks. The primary outcomes were predialysis serum potassium and prevalence of hyperkalemia.

RESULTS

At the end of the study, significantly reduced serum potassium concentrations were observed in the senna glycoside compared with the control (-0.32 [95%CI -0.43, -0.04] vs. -0.02 [95%CI -0.12, 0.05] mEq/L, p < 0.001, respectively). The prevalence of hyperkalemia during the study occurred at 13.8% in the control and 5.4% in the senna glycoside (p = 0.309). No serious adverse events were observed.

CONCLUSION

Among patients with ESRD on hemodialysis, senna glycoside significantly decreases serum potassium level. Senna glycoside is a safe and possibly effective alternative treatment for hyperkalemia in ESRD.

A randomized controlled trial of the effect of ramosetron on postoperative restoration of bowel motility after gynecologic laparoscopic surgery

OBJECTIVE

To investigate the effect of ramosetron after gynecological laparoscopic surgery on the recovery of bowel function.

METHODS

A prospective randomized controlled trial conducted at Kyung Hee University hospital, South Korea, from August 2016 to September 2017. Patients were randomized to receive either 10 mg dexamethasone before induction of anesthesia (control group C), followed by intravenous administration of patient-controlled analgesia (IV-PCA) or 2 ml normal saline before induction of anesthesia and 0.6 mg ramosetron (study group R) administered with IV-PCA.

RESULTS

A total of 88 patients were enrolled. Times to first flatus (group C 23.98 ± 6.31 vs. group R 27.14 ± 9.56 h; P = 0.148) and first defecation (group C 36.16 ± 16.04 vs. group R 43.41 ± 20.01 h; P = 0.138) showed no statistically significant differences. No significant differences were observed in the frequency of postoperative nausea and vomiting (PONV) and demand for additional analgesics. Multiple linear regression for analysis of factors affecting time to first flatus revealed no significant results.

CONCLUSION

Ramosetron did not delay bowel movement recovery after gynecologic laparoscopic surgery and was as effective as dexamethasone in regulating PONV. Ramosetron can be used with IV-PCA without concerns about delay in recovery of bowel function. ClinicalTrials.gov registration number: NCT02849483.

The screening program, incidence, and treatment for tumors in patients with severe motor and intellectual disabilities

BACKGROUND

Recently, aging in patients with severe motor and intellectual disabilities (SMID) has been causing serious problems. There have been few reports about treatment for tumors in patients with SMID.

METHODS

The treatments performed for tumors of 12 SMID patients were examined.

RESULTS

Blood tests and ultrasonography were useful in screening. With regard to treatment, the surgery for SMID patients was performed in the same manner as in healthy cases, and the results were generally satisfactory, without major complications. Typically, the patients were diagnosed in advanced stages; many metachronous double cancers were observed.

CONCLUSIONS

We reported a tumor therapy to the patients with SMID. Our therapy provides satisfactory results for patients with SMID and their families. Further studies are required to clarify the clinical significance of the screening test and the tumor operative method for the patients with SMID.

Disruption of Circadian Rhythms and Gut Motility: An Overview of Underlying Mechanisms and Associated Pathologies

Circadian rhythms ensure that physiological processes occur at the most biologically meaningful time. The circadian timing in the gastrointestinal tract involves interlocking transcriptional and translational feedback loops that culminate in the rhythmic expression and activity of a set of clock genes and related hormones. The suprachiasmatic nucleus and peripheral core molecular clocks oscillate every 24 hours and are responsible for the periodic activity of various segments and transit along the gastrointestinal tract. Environmental cues may alter or reset these rhythms to align them with new circumstances. Colonic motility also follows a circadian rhythm with reduced nocturnal activity. Healthy humans have normal bowel motility during the day, frequently following awakening or following a meal, with minimal activity during the night. Maladjusted circadian rhythms in the bowel have been linked to digestive pathologies, including constipation and irritable bowel syndrome. Our advanced knowledge of the link between the circadian clock and gastrointestinal physiology provides potential therapeutic approaches for the treatment of gastrointestinal diseases. This review seeks to establish evidence for the correlation between circadian rhythm, bowel movements and digestive health, and examine the implications of disrupted circadian rhythms on gut physiology.

Positive Correlation between nNOS and Stress-Activated Bowel Motility Is Confirmed by In Vivo HiBiT System

Neuronal nitric oxide synthase (nNOS) has various roles as a neurotransmitter. However, studies to date have produced insufficient data to fully support the correlation between nNOS and bowel motility. This study aimed to investigate the correlation between nNOS expression and gastrointestinal (GI) tract motility using a stress-induced neonatal maternal separation (NMS) mouse model. In this study, we generated a genetically modified mouse with the HiBiT sequence knock-in into the nNOS gene using CRISPR/Cas9 for analyzing accurate nNOS expression. nNOS expression was measured in the stomach, small intestine, large intestine, adrenal gland, and hypothalamus tissues after establishing the NMS model. The NMS model exhibited a significant increase in nNOS expression in large intestine, adrenal gland, and hypothalamus. Moreover, a significant positive correlation was observed between whole gastrointestinal transit time and the expression level of nNOS. We reasoned that NMS induced chronic stress and consequent nNOS activation in the hypothalamic-pituitary-adrenal (HPA) axis, and led to an excessive increase in intestinal motility in the lower GI tract. These results demonstrated that HiBiT is a sensitive and valuable tool for analyzing in vivo gene activation, and nNOS could be a biomarker of the HPA axis-linked lower intestinal tract dysfunction.

Premigratory neural crest stem cells generate enteric neurons populating the mouse colon and regulating peristalsis in tissue-engineered intestine

Hirschsprung's disease (HSCR) is a common congenital defect. It occurs when bowel colonization by neural crest‐derived enteric nervous system (ENS) precursors is incomplete during the first trimester of pregnancy. Several sources of candidate cells have been previously studied for their capacity to regenerate the ENS, including enteric neural crest stem cells (En‐NCSCs) derived from native intestine or those simulated from human pluripotent stem cells (hPSCs). However, it is not yet known whether the native NCSCs other than En‐NCSCs would have the potential of regenerating functional enteric neurons and producing neuron dependent motility under the intestinal environment. The present study was designed to determine whether premigratory NCSCs (pNCSCs), as a type of the nonenteric NCSCs, could form enteric neurons and mediate the motility. pNCSCs were firstly transplanted into the colon of adult mice, and were found to survive, migrate, differentiate into enteric neurons, and successfully integrate into the adult mouse colon. When the mixture of pNCSCs and human intestinal organoids was implanted into the subrenal capsule of nude mice and grown into the mature tissue‐engineered intestine (TEI), the pNCSCs‐derived neurons mediated neuron‐dependent peristalsis of TEI. These results show that the pNCSCs that were previously assumed to not be induced by intestinal environment or cues can innervate the intestine and establish neuron‐dependent motility. Future cell candidates for ENS regeneration may include nonenteric NCSCs.

The impact of chewing gum on postoperative bowel activity and postoperative pain after total laparoscopic hysterectomy

We aimed to investigate the effects of chewing gum on bowel activity and postoperative pain in patients undergoing laparoscopic hysterectomy. Patients were randomised into two groups (n = 58, study; n = 51, control). In the study group, patients started chewing sugarless gum every 2 h for 15 min, beginning at the second postoperative hour. The control group did not chew gum, and they received standard postoperative care. Both groups were compared primarily in terms of the amount of time until the first bowel movement, the time of the first passage of flatus and the time of first defaecation. The amount of time until the first bowel movement, the time of the first passage of flatus and the time of the first defaecation were found to be significantly shorter in the chewing gum group (p < .001). The amount of postoperative analgesics that were needed and VAS scores at 6-hours and 24-hours postoperatively, were found to be lower in the study group than in the control group (p < .001). Chewing gum was found to have beneficial effects on bowel motility and postoperative pain in patients undergoing laparoscopic hysterectomy. This affordable and simple method could be recommended to patients after total laparoscopic hysterectomy.Impact statementWhat is already known on this subject? Postoperative gastrointestinal dysfunction remains a source of morbidity and the major determinant of length of stay after abdominal operation. The mechanism of enhanced recovery from postoperative gastrointestinal dysfunction with the help of chewing gum is believed to be the cephalic-vagal stimulation of digestion which increases the promotability of neural and humoral factors that act on different parts of the gastrointestinal tract.What do the results of this study add? The findings of previous randomised controlled studies have been inconsistent regarding the effect of chewing gum on postoperative bowel function following abdominal gynecological surgery. In this randomised prospective study, we found that chewing gum early in the postoperative period after total laparoscopic hysterectomy hastened time to bowel motility and flatus. To our knowledge this is the first study of the impact of chewing gum on bowel motility after total laparoscopic hysterectomy.What are the implications of these findings for clinical practice and/or further research? Chewing gum early in the postoperative period following laparoscopic hysterectomy hastens time to bowel motility and flatus. The use of chewing gum is a simple and cheap strategy for promoting the recovery of gastrointestinal functions.

Chronic Intestinal Pseudo-obstruction

Chronic intestinal pseudo-obstruction (CIP) is defined by either continuous or intermittent symptoms of bowel obstruction in the absence of fixed lumen excluding lesion. CIP includes a heterogeneous group of disorders which result either from diseases affecting the enteric neurons and smooth muscle lining or those involving the autonomic innervation of the bowel. Symptoms associated with CIP are nonspecific, which can sometimes contribute to the delay in recognizing the condition and making the correct diagnosis. The diagnostic workup should include imaging and manometry studies and, occasionally, full-thickness bowel biopsies for histopathological examination may be required. Multidisciplinary team approach for the management of these patients is recommended, and the team members should include a gastroenterologist, surgeon, chronic pain specialist, clinical nutritionist, and a psychologist. The treatment goals should include optimizing the nutritional status and preventing or delaying the development of intestinal failure. The majority of the patients require enteral or parenteral nutrition support, and chronic pain is a common and distressing symptom. Small bowel transplantation may be required if patients develop liver complications due to parenteral nutrition, have difficult central line access, or have poor quality of life and worsening pain despite aggressive medical management.

Noninvasive automated motion assessment of intestinal motility by continuously tagged MR imaging

PURPOSE

To evaluate continuously tagged 3 Tesla MRI for monitoring glucagon-induced bowel motility changes in healthy volunteers.

MATERIALS AND METHODS

After standardized oral bowel preparation, 10 healthy volunteers underwent a free-breathing, continuously tagged three-dimensional (3D) dynamic fast-field-echo (FFE), at a 3.36 Hz sampling frequency. One milligram of glucagon was administered intravenously during data acquisition. Each dataset was divided into four temporal sets of 2 min (period 1 to 4). Taglines were tracked automatically using a scale spaced based algorithm. Assessment of global spectral resolution was performed for three frequency intervals: 0.008-0.300 Hz (motility), 0.300-0.400 Hz (breathing motion), and 0.400-0.533 Hz (higher order motion). Additional analyses were performed at fine spectral resolution in frequency bands of 0.033 Hz. Glucagon-induced motility changes were investigated by means of a motility index (spectral power normalized to the maximal spectral power per-volunteer), resulting in a range of 0 to 1 (no motion to maximal motion). Statistical comparison was done for period 1 and 4 (Wilcoxon-signed rank test).

RESULTS

After glucagon administration, a significant decrease in the motility index was found for the low- (0.008-0.300 Hz) (P < 0.0001) and high-frequency interval (0.400-0.533 Hz) (P < 0.0001). Around breathing motion frequencies, no decrease in motility index was detected.

CONCLUSION

Free-breathing, continuously tagged MR imaging is a noninvasive method for automated bowel motility assessment and allows for detection of drug-induced changes.