Ryks, Michael

ABSTRACT Background Gastric emptying (GE) scintigraphy with 4‐h imaging and a radiolabeled chicken egg‐based meal (320 kcal, 30% fat) is the standard test for gastroparesis at Mayo Clinic, with an intraindividual coefficient of variation (COV intra ) of 23.8% for GE half emptying time (T 1/2 ). Alternative meals for patients with dietary restrictions, including egg allergies or vegan diets, are lacking, limiting test accessibility. The study aimed to establish a vegan, lactose‐, nut‐, and gluten‐free meal with similar caloric and fat content to the egg meal and to assess its performance in GE studies. Methods In Vitro: 99m Tc binding to egg meal over 4 h was compared to a calorically and nutritionally similar vegan alternative, JUST Egg, using a validated in vitro model simulating gastric conditions of pH, pepsin, and stirring. In Vivo: 10 healthy participants underwent randomized crossover GE scintigraphy with standard and vegan meals, spaced ≥ 3 days apart to measure GE% at 2 h, 4 h, and GE T 1/2 . Group comparisons and variance analysis included Rank Sum tests and Bland–Altman plots. Key Results In Vitro: A strong correlation ( R = 0.975, p ‐value < 0.01) between 99m Tc binding in the egg and vegan egg models was observed. Minimal variance (< 10%) was recorded at all time points. In Vivo: GE at 4 h and GE T 1/2 showed non‐statistically significant mean differences, < 2% and < 10 min respectively, between both meals. The intra‐individual variability was 18.8%. Conclusions and Inferences The vegan meal demonstrated in vitro stability, in vivo performance comparable to the egg meal, and a COV intra of 18.8%, which was lower than the 23.8% reported in repeat egg meal GE studies. Trial Registration ClinicalTrials.gov number NCT06991036 ( https://clinicaltrials.gov/study/NCT06991036?term=NCT06991036&rank=1 )

INTRODUCTION: Indomethacin is often used experimentally to induce intestinal hyperpermeability, enabling evaluation of interventions targeting barrier function. METHODS: We conducted a randomized, double-blind, placebo-controlled study (NCT05538247) in healthy volunteers to assess whether a supplement could mitigate indomethacin-induced hyperpermeability. Participants received 150 mg/d of indomethacin for 6 days, either before or during placebo/supplement administration. Permeability was measured using 13 C-mannitol and lactulose urinary excretion. RESULTS: Contrary to expectations, indomethacin failed to increase 13 C-mannitol excretion in either group. No meaningful elevations in serum (zonulin, claudins) or fecal (calprotectin) biomarkers were observed. DISCUSSION: Our findings suggest that the expected increase in intestinal permeability after indomethacin administration may not be consistently observed in healthy volunteers. These results highlight the need to carefully consider the reproducibility and sensitivity of this model in future clinical studies aiming to investigate gut barrier function.

INTRODUCTION: Altered intestinal permeability (IP) is implicated in multiple gastrointestinal and systemic disease conditions; an experimental model of perturbed IP in healthy subjects is needed. Traditional approaches to perturbing IP include use of nonsteroidal anti-inflammatory drugs. METHODS: We conducted a single-center, randomized, placebo-controlled pilot study of dose-related effects of castor oil (CO) (and its ingredient ricinoleic acid) at 750, 1,500, or 3,000 mg daily doses on IP. Permeability was assessed using validated 13 C-mannitol and lactulose urine excretion at 0–2, 8–24, and 0–24 hours after oral administration. RESULTS: Permeability analysis across all groups demonstrated significant difference among the groups for 0–2 hours 13 C-mannitol, 0–24 hours 13 C-mannitol, and borderline significant difference for 2–8 hours 13 C-mannitol ( P = 0.060) and 0–24 hours lactulose ( P = 0.056). Direct comparison of 3,000 mg CO vs placebo ( t test) demonstrated higher excretion of 13 C-mannitol and lactulose at 0–2, and 0–24 hours, and lactulose at 2–8 hours. DISCUSSION: CO may perturb small intestinal and colonic permeability in healthy adults.

Abstract Background and Aims Inflammatory bowel disease (IBD) is associated with altered mucus and increased intestinal permeability (IP). Prior reports on permeability in IBD typically used lactulose-to-mannitol ratio (LMR). Food contamination with 12C-mannitol is a significant potential confounder in IP assessment. We aimed to compare small intestinal (SI) and colonic (COL) permeability in IBD, both active (ACT) and in remission (REM), to normal healthy volunteers (NHV). Methods Inflammatory bowel disease activity was based on Simple Endoscopic Score for Crohn’s Disease (SES-CD) and Mayo endoscopy score for ulcerative colitis (UC). We performed 24-hour IP test using 100 mg 13C-mannitol and 1000 mg lactulose with urine collected during 0-2, 2-8, and 8-24 hours. The primary endpoint was mg excretion of 13C-mannitol and lactulose during 2-24 hours reflecting SI and COL permeability. Results Among 17 CD patients, 7 were ACT (SES-CD &gt;6), and 10 REM (SES-CD 0-2). Among 20 UC patients, 10 had ACT (Mayo score 2-3), and 10 REM (Mayo score 0-1). Urinary excretions over 2-24 hours were higher for IBD than NHV: 13C-mannitol (13.8 [IQR 8.8, 18.7] NHV; 18.4 [15.6, 29.9] REM; 19.7 [13.8, 23.6] ACT, P = .003) and lactulose (1.8 [1.3, 3.1] NHV; 3.6 [2.0, 5.0] REM; 3.5 [2.0, 6.6] ACT, P = .006). There was no difference between ACT and REM for any timed urine collection. LMR at 2-24 hours (or 2-8 and 8-24 hours) were not statistically significant between the 3 groups (0.014 [0.010, 0.021] NHV; 0.016 [0.010, 0.023] REM; 0.016 [0.012, 0.038] ACT, P = .237). Conclusions Intestinal permeability is increased in IBD using validated in vivo assay relative to NHV; increased IP in IBD persists during remission.

AbstractBackgroundColonic transit (CT) measured by validated scintigraphy using 111In‐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.MethodsWe 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 T1/2 (AC T1/2), 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 ResultsAmong 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 T1/2 and with fecal BA.Conclusions & Inferences∆GC identified an additional 21%–23% patients with rapid colonic transit among patients with diarrhea and normal GC24.

AbstractBackgroundThis study compared the effects of ondansetron and placebo in patients with diabetes mellitus and symptoms of dyspepsia (diabetic gastroenteropathy [DGE]).MethodsWe performed a randomized, double‐blinded, placebo‐controlled study of ondansetron tablets (8 mg) three times daily for 4 weeks in DGE patients. Symptoms were assessed with the Gastroparesis Cardinal Symptom Index daily diaries. Gastric emptying (GE) of solids (scintigraphy) and duodenal lipid infusions (300 kcal over 2 h) were each assessed twice, with placebo and ondansetron. Drug effects on GE, symptoms during the GE study and during lipid infusion, and daily symptoms were analyzed.Key ResultsOf 41 patients, 37 completed both GE studies and one completed 1; 31 completed both lipid infusions and four only placebo; and all 35 randomized patients completed 4 weeks of treatment. Compared to placebo, ondansetron reduced the severity of fullness (p = 0.02) and belching (p = 0.049) during lipid infusion but did not affect GE T1/2. Both ondansetron and placebo improved daily symptoms versus the baseline period (p < 0.05), but the differences were not significant. In the analysis of covariance of daily symptoms during the treatment period, the interaction term between treatment and the acute effect of ondansetron on symptoms during lipid challenge was significant (p = .024).Conclusions & InferencesOndansetron significantly reduced fullness during enteral lipid infusion in patients with DGE. Overall, ondansetron did not improve daily symptoms versus placebo. But patients in whom ondansetron improved symptoms during enteral lipid challenge were perhaps more likely to experience symptom relief during daily treatment.

Abstract Satiation is the physiologic process that regulates meal size and termination, and it is quantified by the calories consumed to reach satiation. Given its role in energy intake, changes in satiation contribute to obesity's pathogenesis. Our study employed a protocolized approach to study the components of food intake regulation including a standardized breakfast, a gastric emptying study, appetite sensation testing, and a satiation measurement by an ad libitummeal test. These studies revealed that satiation is highly variable among individuals, and while baseline characteristics, anthropometrics, body composition and hormones, contribute to this variability, these factors do not fully account for it. To address this gap, we explored the role of a germline polygenic risk score, which demonstrated a robust association with satiation. Furthermore, we developed a machine-learning-assisted gene risk score to predict satiation and leveraged this prediction to anticipate responses to anti-obesity medications. Our findings underscore the significance of satiation, its inherent variability, and the potential of a genetic risk score to forecast it, ultimately allowing us to predict responses to different anti-obesity interventions.

INTRODUCTION: Cannabidiol (CBD), a CBR2 agonist with limited psychic effects, antagonizes CB1/CB2 receptors. Allelic variation CNR1 (gene for CBR1) rs806378 and FAAH rs324420 were associated with altered gut motility and sensation. This study aimed to compare the pharmacodynamics and clinical effects of a 4-week treatment with pharmaceutical-grade CBD vs placebo and assess the interactions of FAAH and CNR1 gene variants on the effects of CBD in patients with functional dyspepsia (FD). METHODS: We performed a randomized, double-blinded, placebo-controlled (1:1 ratio) study of CBD b.i.d. (20 mg/kg/d according to the US Food and Drug Administration escalation guidance) in FD patients with nondelayed gastric emptying (GE) at baseline. Symptoms were assessed by validated daily symptom diary (0–4 scale for upper abdominal pain, nausea, and bloating), weekly assessment of adequate relief, Leuven Postprandial Distress Scale (8 symptoms, adjectival scores rated 0–4 for severity), and quality of life (Short-Form Nepean Dyspepsia Index [average of 10 dimensions each on a 5-point scale]). After the 4-week treatment, all patients underwent measurements of GE of solids, gastric volumes, and Ensure nutrient satiation test. Statistical analysis compared 2 treatments for all endpoints and the effects of CBD in association with FAAH rs324420 and CNR1 rs806378. RESULTS: CBD and placebo effects on physiological functions and patient response outcomes were not significantly different. There were borderline CBD treatment-by-genotype interactions: rs806378 CNR1 with Leuven Postprandial Distress Scale ( P = 0.06) and GE solids ( P = 0.12). DISCUSSION: Approved doses of CBD used off-label do not relieve FD with normal baseline GE of solids or alter gastric motor functions and satiation. CBD treatment-by-gene interactions suggest potential benefits for postprandial distress with CNR1 rs806378 T allele.