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Su2063 There Is No Relationship Between the Fructose Transporter, GLUT5 and GLUT2, Protein or mRNA Expression Levels in Irritable Bowel Syndrome With Fructose Malabsorption and Intolerance
Su2063
AGA Abstracts
There Is No Relationship Between the Fructose Transporter, GLUT5 and GLUT2, Protein or mRNA Expression Levels in Irritable Bowel Syndrome With Fructose Malabsorption and Intolerance Clive H. Wilder-Smith, Xinhua Li, Reuben K. Wong, Sherry S. Ho, Sai Mun Leong, Hong Kai Lee, Evelyn S. Koay, Ronaldo P. Ferraris Food intolerances are a major complaint in IBS. Fructose intolerance prevalence in IBS is up to 70%, but the causative mechanism is unknown(1). Fructose is transported across the intestinal epithelia by glucose transporters 5 (GLUT5,Slc2a5) and 2 (GLUT2,Slc2a2)(2). In mice, deletion of GLUT5 resulted in malabsorption of dietary fructose and typical signs of intolerance(3). Several of the postulated underlying mechanisms in IBS, e.g. inflammation and stress, reduce GLUT5 expression(2) Recently, no group differences in GLUT5 and GLUT2 protein and mRNA expression in IBS patients with fructose intolerance and controls were shown(4). To further analyze the relationship between fructose-associated symptoms in IBS patients with malabsorption, a correlative analysis with GLUT5 and GLUT2 protein and mRNA expression levels was performed. Duodenal biopsies were obtained in 11 male or female IBS patients with fructose malabsorption and intolerance, diagnosed by breath testing after 8h fasting and ingestion of 35g fructose. Malabsorption was characterized by an increase of H2>20ppm or CH4>10ppm in breath and intolerance was defined by a positive GI-symptom index within 5h of fructose ingestion. 15 matched healthy subjects aged between 18 and 60 years were used as controls. Coeliac's disease and IBD were excluded. mRNA for GLUT5 and GLUT2 was quantified by multiplex RT-qPCR, and expressed as a ratio of β-actin. GLUT5 and GLUT2 protein expression level were determined by Western Blot relative to alpha-tubulin. Analysis was by Spearman Rank correlation and tMannWhitney test for group comparisons. The maximum H2 and CH4 concentrations across all individuals did not correlate with either GLUT5 or GLUT2 mRNA or protein expression levels (r<0.14, p>0.48). There were no significant group differences in GLUT5 mRNA expression levels between fructose intolerant IBS patients (median: 0.18 (IQR 0.13-0.21)) and controls (0.17 (0.12-0.19))(p>0.05). Respective GLUT2 mRNA expressions were 0.26 (0.20-0.31) and 0.26 (0.19-0.31)(p>0.05). There were also no significant group differences in GLUT5 protein expression between patients (0.95 (0.52-1.68) and controls (0.95 (0.591.15))(p>0.05). Respective GLUT2 protein expression levels were 1.56 (1.06-2.14) and 1.35 (0.96-1.79)(p>0.05). Duodenal GLUT5 and GLUT2 mRNA and protein expression did not correlate with fructose malabsorption characterized by classic breath testing, and did not differ significantly between fructose-intolerant IBS patients and healthy controls. Our results suggest that human fructose intolerance or malabsorption may not be associated with marked changes in GLUT5 and GLUT2 mRNA and protein expression. (1)Wilder-Smith CH.. Aliment Pharmacol Ther. 2013;37:1074. (2)Douard V & Ferraris RP. Am J Physiol Endocrinol Metab 2008;295:227 (3)Barone S.. J Biol Chem 2009;284:5056 (4)Wilder-Smith CHl. UEGJ;2013
GRADE summary of findings: Low FODMAP diet compared to unrestricted diet for IBS Su2062 Serum Tryptophan Metabolite Profiling During Sleep in Patients With and Without Irritable Bowel Syndrome (IBS) Margaret Heitkemper, Monica Jarrett, Daniel Raftery, Daniel Djukovic, Haiwei Gu, Kevin Cain Purpose: Poor sleep is commonly reported by patients with IBS. When stressed prior to bedtime patients with IBS show dysregulation of the pituitary-adrenal axis during sleep. Evidence suggests the tryptophan (TRP) metabolic pathways are also altered in patients with IBS. Our purpose was to determine whether alterations in TRP metabolism may be linked to cortisol in women with and without IBS. Methods: Women, ages 18-45, (n=46 IBS [Rome III]; controls [C; n=24]) were studied in a sleep laboratory and serum samples obtained on the third night following the introduction of a social stressor (anticipation of public speaking). Samples were obtained 2 hours following sleep onset (time 1) and 1 hour prior to awakening (time 2). All subjects completed a demographic data sheet, Rome III Diagnostic Questionnaire for Functional GI Disorders, Pittsburgh Quality Sleep Index (PSQI) and 28-day symptom diaries. Serum cortisol levels were determined by ELISA and metabolite levels by targeted liquid chromatography-mass spectrometry (LC-MS). Results: More women with IBS reported symptoms of insomnia (PSQI) as compared to C group (40% versus 24%) and reduced sleep efficiency by polysomnography (p<0.05). As reported previously cortisol/ACTH ratios were higher in IBS as compared to C women. Of the 6 kyneurinine pathway metabolites (primary TRP metabolic route) only niacinamide was significantly higher in women with IBS. However, 5-hydroxytryptophan levels were higher (p<.052) in women with IBS. None of the 3 methylation metabolites were significantly different between IBS and Cs. When ratios of metabolites were calculated significant differences were observed as shown in Table 1. Significant negative correlations between cortisol/ACTH and 5-hydroxytryptophan, methionine, kyneurinine, and betaine were found at one or both time points. TRP levels were significantly correlated with sleep quality (diary) in the IBS group. Conclusion: Nighttime levels of cortisol/ACTH are associated with metabolites in the TRP metabolic pathway particularly those associated with methylation. Whether these associations fully account for the frequent reports of poor sleep in women with IBS requires further study. Table 1
AGA Abstracts
Su2064 Visceral Pain Perception in IBS Patients and Controls in the Fmrii Scanner Environment Is Significantly Altered by Psychological Factors Clive H. Wilder-Smith, Lukas Van Oudenhove, Xinhua Li, Khek-Yu Ho, Reuben K. Wong Background: Brain imaging is used extensively in the investigation of pain processing in humans. Imaging paradigms have examined resting state and functional connectivity during experimental and spontaneous chronic pain in patients and controls. Pain processing is modulated by psychological factors, including anxiety, attention, anticipation and stress. Surprisingly little data exists regarding the induction of psychological effects by the MRI scanner environment itself, although such effects are clinically well-known. Aim: To assess the effect of the scanner environment on pain perception in IBS patients and controls. Methods: Rectal distension pain thresholds were determined by an ascending method of limits protocol using a barostat in 13 male and female IBS patients and 11 healthy controls in a room outside the scanner environment. Pain intensity ratings (VAS 0-100) were recorded at each stimulus step. Subsequently, the pressure inducing moderate pain (VAS 30~40) was applied in outside and inside the fMRI scanner and rectal pain intensity was scored after 30s. Tthe IBS symptom severity score, the Perceived Stress Scale-10 item questionnaire (PSS10), the Hospital Anxiety and Depression Scale (HAD) were also completed. A 2-way mixed ANOVA for ‘group' (IBS vs controls) and ‘scanner' (outside vs inside) effects, including a ‘group'-by-‘scanner' interaction effect were used. ANCOVA with ‘group' and ‘pain ratings inside the scanner' as categorical and continuous independent variables, respectively, and ‘pain ratings outside the scanner' as the dependent variable was performed. Results: Rectal pain increased from 39 (95%CI: 35-42) to 53 (43-63) in IBS and from 42 (31-52) to 49 (39-58) in controls. A significant main ‘scanner' effect (F(1,22)=8.78, p=0.006) due to higher pain scores inside the scanner over both groups was seen. Neither the main effect for group (f1.22=0.01,p=0.92), nor the scanner-by-group interaction were significant (f1.22 =0.66,p= 0.43). The difference in rectal pain outside versus inside correlated significantly with stress (r=-0.76,p=0.006), anxiety (r=-0.68, p=0.02) and depression scores (r=-0.67, p=0.02) in controls, but not in IBS patients. This was confirmed by ANCOVA with the change in rectal pain as dependent variable, where significant group-by-anxiety (p=0.005) group-by-stress (p=0.005) and group-by-depression (p=0.004) interaction effects were seen. Conclusions: Both IBS patients and controls had significantly increased rectal pain intensity inside the MRI scanner compared to outside. Underlying factors appear to differ between patients and controls, where increased stress, anxiety and depression are implicated in the induced hyperalgesia in controls only. Further studies with detailed psychological profiling are indicated, as these results impact a wide range of existing interpretative data.
S-536
AGA Abstracts
There Is No Relationship Between the Fructose Transporter, GLUT5 and GLUT2, Protein or mRNA Expression Levels in Irritable Bowel Syndrome With Fructose Malabsorption and Intolerance Clive H. Wilder-Smith, Xinhua Li, Reuben K. Wong, Sherry S. Ho, Sai Mun Leong, Hong Kai Lee, Evelyn S. Koay, Ronaldo P. Ferraris Food intolerances are a major complaint in IBS. Fructose intolerance prevalence in IBS is up to 70%, but the causative mechanism is unknown(1). Fructose is transported across the intestinal epithelia by glucose transporters 5 (GLUT5,Slc2a5) and 2 (GLUT2,Slc2a2)(2). In mice, deletion of GLUT5 resulted in malabsorption of dietary fructose and typical signs of intolerance(3). Several of the postulated underlying mechanisms in IBS, e.g. inflammation and stress, reduce GLUT5 expression(2) Recently, no group differences in GLUT5 and GLUT2 protein and mRNA expression in IBS patients with fructose intolerance and controls were shown(4). To further analyze the relationship between fructose-associated symptoms in IBS patients with malabsorption, a correlative analysis with GLUT5 and GLUT2 protein and mRNA expression levels was performed. Duodenal biopsies were obtained in 11 male or female IBS patients with fructose malabsorption and intolerance, diagnosed by breath testing after 8h fasting and ingestion of 35g fructose. Malabsorption was characterized by an increase of H2>20ppm or CH4>10ppm in breath and intolerance was defined by a positive GI-symptom index within 5h of fructose ingestion. 15 matched healthy subjects aged between 18 and 60 years were used as controls. Coeliac's disease and IBD were excluded. mRNA for GLUT5 and GLUT2 was quantified by multiplex RT-qPCR, and expressed as a ratio of β-actin. GLUT5 and GLUT2 protein expression level were determined by Western Blot relative to alpha-tubulin. Analysis was by Spearman Rank correlation and tMannWhitney test for group comparisons. The maximum H2 and CH4 concentrations across all individuals did not correlate with either GLUT5 or GLUT2 mRNA or protein expression levels (r<0.14, p>0.48). There were no significant group differences in GLUT5 mRNA expression levels between fructose intolerant IBS patients (median: 0.18 (IQR 0.13-0.21)) and controls (0.17 (0.12-0.19))(p>0.05). Respective GLUT2 mRNA expressions were 0.26 (0.20-0.31) and 0.26 (0.19-0.31)(p>0.05). There were also no significant group differences in GLUT5 protein expression between patients (0.95 (0.52-1.68) and controls (0.95 (0.591.15))(p>0.05). Respective GLUT2 protein expression levels were 1.56 (1.06-2.14) and 1.35 (0.96-1.79)(p>0.05). Duodenal GLUT5 and GLUT2 mRNA and protein expression did not correlate with fructose malabsorption characterized by classic breath testing, and did not differ significantly between fructose-intolerant IBS patients and healthy controls. Our results suggest that human fructose intolerance or malabsorption may not be associated with marked changes in GLUT5 and GLUT2 mRNA and protein expression. (1)Wilder-Smith CH.. Aliment Pharmacol Ther. 2013;37:1074. (2)Douard V & Ferraris RP. Am J Physiol Endocrinol Metab 2008;295:227 (3)Barone S.. J Biol Chem 2009;284:5056 (4)Wilder-Smith CHl. UEGJ;2013
GRADE summary of findings: Low FODMAP diet compared to unrestricted diet for IBS Su2062 Serum Tryptophan Metabolite Profiling During Sleep in Patients With and Without Irritable Bowel Syndrome (IBS) Margaret Heitkemper, Monica Jarrett, Daniel Raftery, Daniel Djukovic, Haiwei Gu, Kevin Cain Purpose: Poor sleep is commonly reported by patients with IBS. When stressed prior to bedtime patients with IBS show dysregulation of the pituitary-adrenal axis during sleep. Evidence suggests the tryptophan (TRP) metabolic pathways are also altered in patients with IBS. Our purpose was to determine whether alterations in TRP metabolism may be linked to cortisol in women with and without IBS. Methods: Women, ages 18-45, (n=46 IBS [Rome III]; controls [C; n=24]) were studied in a sleep laboratory and serum samples obtained on the third night following the introduction of a social stressor (anticipation of public speaking). Samples were obtained 2 hours following sleep onset (time 1) and 1 hour prior to awakening (time 2). All subjects completed a demographic data sheet, Rome III Diagnostic Questionnaire for Functional GI Disorders, Pittsburgh Quality Sleep Index (PSQI) and 28-day symptom diaries. Serum cortisol levels were determined by ELISA and metabolite levels by targeted liquid chromatography-mass spectrometry (LC-MS). Results: More women with IBS reported symptoms of insomnia (PSQI) as compared to C group (40% versus 24%) and reduced sleep efficiency by polysomnography (p<0.05). As reported previously cortisol/ACTH ratios were higher in IBS as compared to C women. Of the 6 kyneurinine pathway metabolites (primary TRP metabolic route) only niacinamide was significantly higher in women with IBS. However, 5-hydroxytryptophan levels were higher (p<.052) in women with IBS. None of the 3 methylation metabolites were significantly different between IBS and Cs. When ratios of metabolites were calculated significant differences were observed as shown in Table 1. Significant negative correlations between cortisol/ACTH and 5-hydroxytryptophan, methionine, kyneurinine, and betaine were found at one or both time points. TRP levels were significantly correlated with sleep quality (diary) in the IBS group. Conclusion: Nighttime levels of cortisol/ACTH are associated with metabolites in the TRP metabolic pathway particularly those associated with methylation. Whether these associations fully account for the frequent reports of poor sleep in women with IBS requires further study. Table 1
AGA Abstracts
Su2064 Visceral Pain Perception in IBS Patients and Controls in the Fmrii Scanner Environment Is Significantly Altered by Psychological Factors Clive H. Wilder-Smith, Lukas Van Oudenhove, Xinhua Li, Khek-Yu Ho, Reuben K. Wong Background: Brain imaging is used extensively in the investigation of pain processing in humans. Imaging paradigms have examined resting state and functional connectivity during experimental and spontaneous chronic pain in patients and controls. Pain processing is modulated by psychological factors, including anxiety, attention, anticipation and stress. Surprisingly little data exists regarding the induction of psychological effects by the MRI scanner environment itself, although such effects are clinically well-known. Aim: To assess the effect of the scanner environment on pain perception in IBS patients and controls. Methods: Rectal distension pain thresholds were determined by an ascending method of limits protocol using a barostat in 13 male and female IBS patients and 11 healthy controls in a room outside the scanner environment. Pain intensity ratings (VAS 0-100) were recorded at each stimulus step. Subsequently, the pressure inducing moderate pain (VAS 30~40) was applied in outside and inside the fMRI scanner and rectal pain intensity was scored after 30s. Tthe IBS symptom severity score, the Perceived Stress Scale-10 item questionnaire (PSS10), the Hospital Anxiety and Depression Scale (HAD) were also completed. A 2-way mixed ANOVA for ‘group' (IBS vs controls) and ‘scanner' (outside vs inside) effects, including a ‘group'-by-‘scanner' interaction effect were used. ANCOVA with ‘group' and ‘pain ratings inside the scanner' as categorical and continuous independent variables, respectively, and ‘pain ratings outside the scanner' as the dependent variable was performed. Results: Rectal pain increased from 39 (95%CI: 35-42) to 53 (43-63) in IBS and from 42 (31-52) to 49 (39-58) in controls. A significant main ‘scanner' effect (F(1,22)=8.78, p=0.006) due to higher pain scores inside the scanner over both groups was seen. Neither the main effect for group (f1.22=0.01,p=0.92), nor the scanner-by-group interaction were significant (f1.22 =0.66,p= 0.43). The difference in rectal pain outside versus inside correlated significantly with stress (r=-0.76,p=0.006), anxiety (r=-0.68, p=0.02) and depression scores (r=-0.67, p=0.02) in controls, but not in IBS patients. This was confirmed by ANCOVA with the change in rectal pain as dependent variable, where significant group-by-anxiety (p=0.005) group-by-stress (p=0.005) and group-by-depression (p=0.004) interaction effects were seen. Conclusions: Both IBS patients and controls had significantly increased rectal pain intensity inside the MRI scanner compared to outside. Underlying factors appear to differ between patients and controls, where increased stress, anxiety and depression are implicated in the induced hyperalgesia in controls only. Further studies with detailed psychological profiling are indicated, as these results impact a wide range of existing interpretative data.
S-536