Background
Short‐chain fructooligosaccharides (scFOS) have beneficial effects in subjects with minor digestive complaints, but the potential mechanisms involved have not been elucidated. The aim of ...the study was to evaluate changes in rectal sensitivity related to the clinical effects of scFOS in a selected group of patients with irritable bowel syndrome (IBS) and rectal hypersensitivity.
Methods
In 79 IBS patients (defined by Rome III criteria) with rectal hypersensitivity (defined as discomfort threshold ≤44 g) a parallel, placebo‐controlled, randomized, and double‐blind study was performed to assess the effects of dietary supplementation (5 g d−1) with scFOS vs placebo for 4 weeks on rectal sensitivity (primary outcome: tolerance to increasing wall tension applied by a tensostat), clinical outcomes (IBS, anxiety/depression and quality of life scores) and composition of fecal microbiota.
Key Results
Rectal discomfort threshold, and IBS and quality of life scores, significantly improved during treatment, but in a similar manner in both scFOS and placebo groups; a post‐hoc analysis showed that the effect of scFOS on rectal sensitivity was more pronounced in constipation‐predominant‐IBS patients (P=.051 vs placebo). Contrary with placebo, scFOS significantly reduced anxiety scores and increased fecal Bifidobacteria (P<.05 for both) without modifying other bacterial groups.
Conclusions & Interfences
The effect of scFOS on anxiety may be related to modulation of the gut microbiota; demonstration of effects of scFOS on rectal sensitivity may require higher doses and may depend on the IBS subgroup.
Our aim was to evaluate the effects of short‐chain fructooligosaccharides (scFOS) on rectal sensitivity, fecal microbiota, and symptoms in patients with irritable bowel syndrome. Rectal sensitivity improved with scFOS and placebo alike; however, scFOS, but not placebo, significantly increased fecal Bifidobacteria and reduced anxiety score.
Summary
Background
Prebiotics have been shown to reduce abdominal symptoms in patients with functional gut disorders, despite that they are fermented by colonic bacteria and may induce gas‐related ...symptoms.
Aim
To investigate changes in the metabolic activity of gut microbiota induced by a recognised prebiotic.
Methods
Healthy subjects (n = 20) were given a prebiotic (2.8 g/day HOST‐G904, HOST Therabiomics, Jersey, Channel Islands) for 3 weeks. During 3‐day periods immediately before, at the beginning and at the end of the administration subjects were put on a standard diet (low fibre diet supplemented with one portion of high fibre foods) and the following outcomes were measured: (i) number of daytime gas evacuations for 2 days by means of an event marker; (ii) volume of gas evacuated via a rectal tube during 4 h after a test meal; and (iii) microbiota composition by faecal Illumina MiSeq sequencing.
Results
At the beginning of administration, HOST‐G904 significantly increased the number of daily anal gas evacuations (18 ± 2 vs. 12 ± 1 pre‐administration; P < 0.001) and the volume of gas evacuated after the test meal (236 ± 23 mL vs. 160 ± 17 mL pre‐administration; P = 0.006). However, after 3 weeks of administration, these effects diminished (11 ± 2 daily evacuations, 169 ± 23 mL gas evacuation). At day 21, relative abundance of butyrate producers (Lachnospiraceae) correlated inversely with the volume of gas evacuated (r = −0.52; P = 0.02).
Conclusion
The availability of substrates induces an adaptation of the colonic microbiota activity in bacterial metabolism, which produces less gas and associated issues. Clinical trials.gov NCT02618239.
Linked ContentThis article is linked to Staudacher paper. To view this article visit https://doi.org/10.1111/apt.13976.
Background
We have shown that a galactooligosaccharide prebiotic administration (HOST‐G904) initially increased intestinal gas production and this increase declined back to baseline after 2 week ...administration. Our aim was to determine the mechanism of microbiota adaptation; i.e., to determine whether the net reduction is due to decreased overall production or increased gas consumption.
Methods
In 10 healthy subjects, intestinal gas production and intraluminal disposal was measured before, at the beginning and after 2 week of HOST‐G904 prebiotic administration. Anal gas was collected for 4 hour after a probe meal. Paired studies were performed without and with high‐rate infusion of exogenous gas (24 mL/min) into the jejunum to wash‐out the endogenous gas produced by bacterial fermentation. The exogenous gas infused was labeled (5% SF6) to calculate the proportion of endogenous gas evacuated.
Key Results
The volume of intestinal gas produced i.e., endogenous gas washed‐out, increased by 37% at the beginning of HOST‐G904 administration (P=.049 vs preadministration) and decreased down to preadministration level after 2 week administration (P=.030 vs early administration). The proportion of gas eliminated from the lumen before reaching the anus tended to increase after 2‐week administration (87±3% vs 78±5% preadministration; P=.098).
Conclusions & Inferences
Adaptation to regular consumption of HOST‐G904 prebiotic involves a shift in microbiota metabolism toward low‐gas producing pathways, with a non‐significant increase in gas‐consuming activity. Hence, regular consumption of HOST‐G904 regulates intestinal gas metabolism: less gas is produced and a somewhat larger proportion of it is consumed.
Effect of HOST‐G904 administration on the volume of gas evacuated. Anal evacuation of endogenous gas (produced by bacterial fermentation) 2‐4 hours after a probe meal with and without gaseous wash‐out measured before, at the beginning and after 2 week administration (n=10). With gaseous wash‐out, most endogenous gas produced by colonic fermentation was flushed out and evacuated per anus: gas production increased in the early administration phase and returned back to baseline. Without wash‐out, a large proportion of the gas produced by bacterial fermentation was eliminated from the lumen before reaching the anus and the proportion tended to increase during HOST‐G904 administration.
View the podcast on this paper at the following sites: iTunes: https://itunes.apple.com/gb/podcast/neurogastroenterology-motility-september-2017/id1257018975 Youtube: https://youtu.be/YDdDPaSnzuc
Background
Ingestion of a meal induces cognitive and hedonic sensations and our aim was to determine the relation between both dimensions.
Methods
In three groups of healthy non‐obese men (n=10 per ...group) three types of meals with equivalent levels of palatability were tested: a liquid meal, a solid‐liquid low‐calorie meal, and a solid‐liquid high‐calorie meal. The cognitive and hedonic responses were measured on 10‐cm scales before and during the 30‐minute postprandial period.
Key Results
The liquid meal induced a relatively strong cognitive response with satiation (4.7±0.7 score increment), fullness (3.3±0.7 score increment), and inhibition of desire of eating a food of choice; in contrast, its impact on sensation of digestive well‐being and satisfaction was not significant (0.7±0.7 score increment). The high‐calorie solid‐liquid meal, with larger volume load and caloric content, induced much lower satiation (2.4±0.8 score increment; P=.041 vs liquid meal) and fullness sensation (1.3±0.6 score increment; P=.031 vs liquid meal), but a markedly higher level of satisfaction (2.7±0.4 score increment; P=.021 vs liquid meal); the low‐calorie mixed meal had less prominent effects with significantly lower satisfaction (1.0±0.4 score increment; P=.039 vs high‐calorie meal).
Conclusions and Inferences
The cognitive (satiation, fullness) and hedonic responses (satisfaction) to meals with equivalent levels of palatability, that is, equally likable, are dissociable. The characteristics of meals in terms of satiation and rewarding power could be adapted to specific clinical targets, whether nutritional supplementation or restriction.
The cognitive (satiation, fullness) and hedonic responses (satisfaction) to meals with equivalent levels of palatability, that is, equally likable, are dissociable. Hence, the early gustatory experience does not predict postprandial satisfaction.
Background
The metabolic activity of colonic microbiota is influenced by diet; however, the relationship between metabolism and colonic content is not known. Our aim was to determine the effect of ...meals, defecation, and diet on colonic content.
Methods
In 10 healthy subjects, two abdominal MRI scans were acquired during fasting, 1 week apart, and after 3 days on low‐ and high‐residue diets, respectively. With each diet, daily fecal output and the number of daytime anal gas evacuations were measured. On the first study day, a second scan was acquired 4 hours after a test meal (n=6) or after 4 hours with nil ingestion (n=4). On the second study day, a scan was also acquired after a spontaneous bowel movement.
Results
On the low‐residue diet, daily fecal volume averaged 145 ± 15 mL; subjects passed 10.6 ± 1.6 daytime anal gas evacuations and, by the third day, non‐gaseous colonic content was 479 ± 36 mL. The high‐residue diet increased the three parameters to 16.5 ± 2.9 anal gas evacuations, 223 ± 19 mL fecal output, and 616 ± 55 mL non‐gaseous colonic content (P<.05 vs low‐residue diet for all). On the low‐residue diet, non‐gaseous content in the right colon had increased by 41 ± 11 mL, 4 hours after the test meal, whereas no significant change was observed after 4‐hour fast (−15 ± 8 mL; P=.006 vs fed). Defecation significantly reduced the non‐gaseous content in distal colonic segments.
Conclusion & Inferences
Colonic content exhibits physiologic variations with an approximate 1/3 daily turnover produced by meals and defecation, superimposed over diet‐related day‐to‐day variations.
Ingestion of unabsorbable residues and defecation produce profound changes in colonic content. The rapid turnover of colonic biomass (about 1/3 daily) indicates a high adaptation potential of microbiota to the intraluminal environment.
Background
Food palatability has been shown to influence satiation and meal consumption; our aim was to determine its effects on postprandial satisfaction, ie digestive well‐being (primary outcome), ...and homeostatic sensations (satiety, fullness).
Methods
Randomized, cross‐over trial comparing the postprandial responses to conventional (potato‐cheese cream followed by vanilla cream) vs unconventional test meals (mixture of both creams) with identical composition and physical characteristics (color, texture, consistency, temperature) but distinctively different palatability. In 22 non‐obese healthy men sensations were measured on 10 cm scales before and during the 60‐min postprandial period (−5 to +5 score scales for palatability, satiety, well‐being, and mood, and 0‐10 score scales for fullness and discomfort). Comparisons between meals were performed with a 2‐way repeated measures ANCOVA with premeal data as co‐variate.
Key Results
As compared to the palatable conventional meal, the unconventional meal was rated unpalatable (−1.8 ± 0.4 score vs 2.8 ± 0.1 score potato cream and 2.9 ± 0.2 vanilla cream; P < .001 for both), induced significantly more fullness sensation meal effect F (1, 19) = 7.389; P = .014 but had less effect on digestive well‐being meal effect F (1, 19) = 47.016; P < .001 and mood meal‐effect F (1, 19) = 6.609; P = .019. The difference in satiety was not significantly different.
Conclusion & Inferences
Meal palatability influences the postprandial experience: it bears a direct relation to the hedonic response (well‐being/mood) but an inverse relation to homeostatic sensations (fullness). These relations could be applicable to influence eating behavior, because at equal conditions, more palatable meals induce less fullness but more satisfaction, and vice‐versa.
Effect of meal palatability on the postprandial experience. As compared to the palatable two‐course meal, the unconventional mixed meal induced more fullness and some degree of abdominal discomfort with significantly lower levels of digestive well‐being. P values of main meal‐effect by two‐way repeated measures ANCOVA shown; dependent variable: postprandial scores; covariate: premeal scores.
Appetite influences the responses to meal ingestion Pribic, T.; Nieto, A.; Hernandez, L. ...
Neurogastroenterology and motility,
August 2017, 2017-Aug, 2017-08-00, 20170801, Volume:
29, Issue:
8
Journal Article
Peer reviewed
Background
We have previously shown that the postprandial experience includes cognitive sensations, such as satiety and fullness, with a hedonic dimension involving digestive well‐being and mood. ...Preload conditioning has been shown to modulate appetite and food consumption under certain conditions, but its effects on the responses to meal ingestion are not clear. We hypothesized that appetite modulation by preload conditioning has differential effects on the cognitive and the emotive responses to meal ingestion.
Methods
The effects of preload conditioning (ingestion of a low‐ vs a high‐calorie breakfast) on appetite and on the cognitive and emotive responses to a comfort probe meal ingested 2 hours later (ham and cheese sandwich with orange juice; 300 mL, 425 Kcal) was tested in healthy subjects (n=12) in a cross‐over design. Sensations were measured at regular intervals 15 minutes before and 60 minutes after the probe meal.
Key Results
As compared to the low‐calorie breakfast, the high‐calorie breakfast reduced basal hunger sensation and influenced the responses to the subsequent probe meal: it increased satiety (4.3±0.2 score vs 2.7±0.2 score; P<.001) and fullness (5.4±0.5 score vs 3.1±0.5; P<.001), but reduced the expected postprandial experience of digestive well‐being after a palatable meal (1.3±0.7 score vs 3.0±0.3; P=.045).
Conclusion and Inferences
Appetite modulation by preload conditioning has differential effects on the cognitive and emotive responses to a meal. Preload conditioning of the postprandial experience may be applicable to dietary planning and prevention of postprandial symptoms.
Effect of appetite on the responses to a meal. As compared to a low‐calorie breakfast, a high‐calorie breakfast reduced basal hunger sensation, and selectively influenced the responses to a meal ingested 2 hour later: it increased satiety and fullness, but reduced the expected postprandial experience of digestive well‐being.
Background
Intestinal manometry is the current standard for direct evaluation of small bowel dysmotility. Patients with abnormal motility can either be diagnosed of pseudo‐obstruction when there are ...radiological findings mimicking mechanical intestinal obstruction or of enteric dysmotility when these findings are absent. The aim of the present study was to prospectively compare small bowel manometric abnormalities with histopathological findings in intestinal full‐thickness biopsies in patients with severe dysmotility disorders.
Methods
We investigated 38 patients with intestinal manometry and a subsequent full‐thickness intestinal biopsy. Manometric recordings were read by 4 investigators and a diagnostic consensus was obtained in 35 patients. Histopathological analysis, including specific immunohistochemical techniques of small bowel biopsies was performed and compared to manometric readings.
Key Results
Patients with abnormal intestinal manometry had abnormal histopathological findings in 73% of cases. However, manometric patterns did not match with the specific neuromuscular abnormalities. Among patients with a neuropathic manometry pattern and abnormal histopathology, only 23% had an enteric neuropathy, whereas 62% had neuromuscular inflammation, and 15% an enteric myopathy. On the other hand, patients with a myopathic manometry pattern all had abnormal histopathology, however, none of them with signs of enteric myopathy.
Conclusion & Inferences
Small bowel dysmotility detected by intestinal manometry is often associated with abnormal neuromuscular findings in full‐thickness biopsies. However, there is no correlation between the specific manometric patterns and the histopathological findings.
Small bowel dysmotility detected by intestinal manometry is often associated with abnormal neuromuscular findings in full‐thickness biopsies, however, there is no correlation between the manometric patterns and the underlying histopathological findings. The figure shows the neuromuscular component of a jejunal biopsy with a dense CD3‐positive lymphocytic infiltrate within the myenteric plexus (A) and throughout the circular muscle adjacent to nerve fibers (B).
Background
Inhibitory neuromuscular transmission in the human colon is due to nitrergic and purinergic (P2Y1‐mediated) inputs. The aim of this study was to determine the mechanisms of neuromuscular ...transmission in different regions of the human small intestine.
Methods
Ileal (n = 6) and jejunal (n = 6) samples underwent histological examination and were studied using sharp microelectrodes in smooth muscle cells and conventional muscle bath techniques. Electrical field stimulation (EFS) was used to stimulate inhibitory neurons.
Key Results
No histological abnormalities were found. Resting membrane potential was −39.7 ± 1.5 and −45.5 ± 2.1 mV in the jejunum and ileum, respectively. Slow waves and spontaneous contractions were recorded at a frequency of about 8–9 and 6–7 cpm in the jejunum and ileum, respectively. In non‐adrenergic, non‐cholinergic conditions, EFS caused an inhibitory junction potential and mechanical relaxation. Both responses were blocked by tissue incubation with the nitric oxide synthase inhibitor (Nω‐nitro‐l‐arginine 1 mM) and the P2Y1 receptor blocker 2′‐deoxy‐N6‐methyladenosine 3′,5′‐bisphosphate tetrasodium salt (MRS2179; 10 μM). Both exogenous addition of sodium nitroprusside (1 μM) and the preferential P2Y1 receptor agonist ADPβS (1 μM) hyperpolarized and relaxed smooth muscle cells. MRS2179 (10 μM) blocked ADPβS‐induced responses.
Conclusions & Inferences
Similar to colon, inhibitory neurotransmission in the human small intestine is mainly mediated by purinergic (via P2Y1 receptors) and nitrergic inhibitory neurotransmission. Similar mechanisms of inhibitory neurotransmission are present in different regions of the human intestine.
In this article, we studied inhibitory neuromuscular transmission in the human small intestine. Purinergic and Nitrergic responses were identified. P2Y1 receptors mediate the purinergic response in the human intestine.
Background
We recently reported interrelated digestive, cognitive, and hedonic responses to a meal. The aim of this study was to identify brain networks related to the hedonic response to eating.
...Methods
Thirty‐eight healthy subjects (20‐38 age range) were evaluated after a 5‐hour fast and after ingestion of a test meal (juice and warm ham and cheese sandwich, 300 mL, 425 kcal). Perceptual and affective responses (satiety, abdominal fullness, digestive well‐being, and positive mood), and resting scans of the brain using functional MRI (3T Trio, Siemens, Germany) were evaluated immediately before and after the test meal. A high‐order group independent component analysis was performed to investigate ingestion‐related changes in the intrinsic connectivity of brain networks, with a focus on thalamic and insular networks.
Key Results
Ingestion induced satiation (3.3±0.4 score increase; P<.001) and abdominal fullness (2.4±0.3 score increase; P<.001). These sensations included an affective dimension involving digestive well‐being (2.8±0.3 score increase; P<.001) and positive mood (1.8±0.2 score increase; P<.001). In general, thalamo‐cortical connectivity increased with meal ingestion while insular‐cortical connectivity mainly decreased. Furthermore, larger meal‐induced changes (increase/decrease) in specific thalamic connections were associated with smaller changes in satiety/fullness. In contrast, a larger meal‐induced decrease in insular‐anterior cingulate cortex connectivity was associated with increased satiety, fullness, and digestive well‐being.
Conclusions and Inferences
Perceptual and emotional responses to food intake are related to brain connectivity in defined functional networks. Brain imaging may provide objective biomarkers of subjective effects of meal ingestion.
Meal ingestion induces cognitive and hedonic sensations, and our aim was to identify brain networks related to these sensations. Perceptual and emotional responses to food intake are related to brain connectivity in defined functional networks. Brain imaging may provide objective biomarkers of subjective effects of meal ingestion.
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