| 1. |
- Bonfiglio, F., et al.
(författare)
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Female-Specific Association Between Variants on Chromosome 9 and Self-Reported Diagnosis of Irritable Bowel Syndrome
- 2018
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Ingår i: Gastroenterology. - : Elsevier BV. - 0016-5085 .- 1528-0012. ; 155:1, s. 168-179
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: Genetic factors are believed to affect risk for irritable bowel syndrome (IBS), but there have been no sufficiently powered and adequately sized studies. To identify DNA variants associated with IBS risk, we performed a genome-wide association study (GWAS) of the large UK Biobank population-based cohort, which includes genotype and health data from 500,000 participants. METHODS: We studied 7,287,191 high-quality single nucleotide polymorphisms in individuals who self-reported a doctor's diagnosis of IBS (cases; n = 9576) compared to the remainder of the cohort (controls; n = 336,499) (mean age of study subjects, 40-69 years). Genome-wide significant findings were further investigated in 2045 patients with IBS from tertiary centers and 7955 population controls from Europe and the United States, and a small general population sample from Sweden (n = 249). Functional annotation of GWAS results was carried out by integrating data from multiple biorepositories to obtain biological insights from the observed associations. RESULTS: We identified a genome-wide significant association on chromosome 9q31.2 (single nucleotide polymorphism rs10512344; P = 3.57 x 10(-8)) in a region previously linked to age at menarche, and 13 additional loci of suggestive significance (P < 5.0 x 10(-6)). Sex-stratified analyses revealed that the variants at 9q31.2 affect risk of IBS in women only (P = 4.29 x 10(-10) in UK Biobank) and also associate with constipation-predominant IBS in women (P = .015 in the tertiary cohort) and harder stools in women (P = .0012 in the population-based sample). Functional annotation of the 9q31.2 locus identified 8 candidate genes, including the elongator complex protein 1 gene (ELP1 or IKB-KAP), which is mutated in patients with familial dysautonomia. CONCLUSIONS: In a sufficiently powered GWAS of IBS, we associated variants at the locus 9q31.2 with risk of IBS in women. This observation may provide additional rationale for investigating the role of sex hormones and autonomic dysfunction in IBS.
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| 2. |
- Borg, Julia, et al.
(författare)
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Oxytocin reduces satiety scores without affecting the volume of nutrient intake or gastric emptying rate in healthy subjects.
- 2011
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Ingår i: Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society. - : Wiley. - 1365-2982. ; 23:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Oxytocin is expressed throughout the gastrointestinal tract and is released in response to a fatty meal. Administration of an oxytocin receptor antagonist prolongs the gastric emptying rate. The aim of this study was to examine the effect of oxytocin on gastric accommodation, gastric emptying time, and satiety after food intake. Methods Ten healthy subjects participated in a slow satiety drinking test with a liquid meal. Every 5min the subjects scored their sensation of satiety using a visual analogue scale (VAS) until maximum satiety was reached and the amount of liquid intake was determined. Twelve subjects participated in a gastric emptying test. They were given a standardized meal containing 20 radio-opaque markers, after which fluoroscopy was performed and VAS was scored every hour. Both tests were performed four times during infusions of saline and three different oxytocin concentrations. Blood was collected for oxytocin concentration measurements. Key Results There were no differences in the volume of nutrient intake at maximum satiety between the three doses of oxytocin and saline. However, lower satiety scores at maximum satiety were seen after oxytocin infusion (P=0.031), with 40mUmin(-1) being the most effective dosage (P=0.013), and this was also true 30min after finishing the meal (P=0.032). There was no difference in gastric emptying time between saline and oxytocin. The oxytocin concentration in plasma was increased proportional to the oxytocin infusions. Conclusions & Inferences Infusion of oxytocin reduces satiety without affecting the volume of nutrient intake or gastric emptying in healthy subjects.
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| 3. |
- Eijsbouts, C., et al.
(författare)
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Genome-wide analysis of 53,400 people with irritable bowel syndrome highlights shared genetic pathways with mood and anxiety disorders
- 2021
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 53:11, s. 1543-1552
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Tidskriftsartikel (refereegranskat)abstract
- Irritable bowel syndrome (IBS) results from disordered brain–gut interactions. Identifying susceptibility genes could highlight the underlying pathophysiological mechanisms. We designed a digestive health questionnaire for UK Biobank and combined identified cases with IBS with independent cohorts. We conducted a genome-wide association study with 53,400 cases and 433,201 controls and replicated significant associations in a 23andMe panel (205,252 cases and 1,384,055 controls). Our study identified and confirmed six genetic susceptibility loci for IBS. Implicated genes included NCAM1, CADM2, PHF2/FAM120A, DOCK9, CKAP2/TPTE2P3 and BAG6. The first four are associated with mood and anxiety disorders, expressed in the nervous system, or both. Mirroring this, we also found strong genome-wide correlation between the risk of IBS and anxiety, neuroticism and depression (rg > 0.5). Additional analyses suggested this arises due to shared pathogenic pathways rather than, for example, anxiety causing abdominal symptoms. Implicated mechanisms require further exploration to help understand the altered brain–gut interactions underlying IBS. © 2021, The Author(s).
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| 4. |
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| 5. |
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| 6. |
- Henstrom, M., et al.
(författare)
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Functional variants in the sucrase-isomaltase gene associate with increased risk of irritable bowel syndrome
- 2018
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Ingår i: Gut. - : BMJ. - 0017-5749 .- 1468-3288. ; 67:2, s. 263-270
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Tidskriftsartikel (refereegranskat)abstract
- Objective IBS is a common gut disorder of uncertain pathogenesis. Among other factors, genetics and certain foods are proposed to contribute. Congenital sucraseisomaltase deficiency (CSID) is a rare genetic form of disaccharide malabsorption characterised by diarrhoea, abdominal pain and bloating, which are features common to IBS. We tested sucrase-isomaltase (SI) gene variants for their potential relevance in IBS. Design We sequenced SI exons in seven familial cases, and screened four CSID mutations (p.Val557Gly, p. Gly1073Asp, p.Arg1124Ter and p.Phe1745Cys) and a common SI coding polymorphism (p.Val15Phe) in a multicentre cohort of 1887 cases and controls. We studied the effect of the 15Val to 15Phe substitution on SI function in vitro. We analysed p.Val15Phe genotype in relation to IBS status, stool frequency and faecal microbiota composition in 250 individuals from the general population. Results CSID mutations were more common in patients than asymptomatic controls (p=0.074; OR=1.84) and Exome Aggregation Consortium reference sequenced individuals (p=0.020; OR=1.57). 15Phe was detected in 6/7 sequenced familial cases, and increased IBS risk in case-control and population-based cohorts, with best evidence for diarrhoea phenotypes (combined p=0.00012; OR=1.36). In the population-based sample, 15Phe allele dosage correlated with stool frequency (p=0.026) and Parabacteroides faecal microbiota abundance (p=0.0024). The SI protein with 15Phe exhibited 35% reduced enzymatic activity in vitro compared with 15Val (p<0.05). Conclusions SI gene variants coding for disaccharidases with defective or reduced enzymatic activity predispose to IBS. This may help the identification of individuals at risk, and contribute to personalising treatment options in a subset of patients.
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| 7. |
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| 8. |
- Ohlsson, Bodil, et al.
(författare)
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Effects of long-term treatment with oxytocin in chronic constipation; a double blind, placebo-controlled pilot trial.
- 2005
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Ingår i: Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society. - : Wiley. - 1350-1925 .- 1365-2982. ; 17:5, s. 697-704
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Oxytocin and its receptor have been found throughout the gastrointestinal (GI) tract, where it affects gut function. Clinically, we have noticed an improvement of bowel habits during lactation in constipated women. The aim of this study was to examine whether oxytocin has an effect on bowel symptoms and psychological well being in women with refractory constipation. METHODS: Fifty-nine women with refractory constipation were included in a double blind, multicentre study. After a 2-week run-in period, they were randomly allocated to nasal inhalation of either placebo or oxytocin treatment twice daily for 13 weeks, followed by a 2 weeks, posttreatment period. The patients completed a questionnaire every day concerning bowel habits, abdominal pain and discomfort, and Gastrointestinal Symptoms Rating Scale (GSRS) and Psychological General Well-being (PGWB) twice during the study; namely, during the baseline period and at the end of the treatment period. RESULTS: Both oxytocin and placebo led to improvement of the constipation according to the GSRS and led to improvement in the sensation of incomplete evacuation and anorectal obstruction, without significant differences between the groups. Abdominal pain and discomfort responded weakly to oxytocin, with no effect of the placebo. In a subgroup of patients with IBS and concomitant depression, a weak improvement in depressed mood was observed after oxytocin administartion. CONCLUSION: Nasal administration of oxytocin had no significant advantage over placebo concerning an effect on constipation. However, it seems to have a positive effect on abdominal pain and discomfort and depressed mood. These findings should be further explored.
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| 9. |
- Ohlsson, Bodil, et al.
(författare)
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Oxytocin stimulates colonic motor activity in healthy women.
- 2004
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Ingår i: Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society. - : Wiley. - 1350-1925 .- 1365-2982. ; 16:2, s. 233-40
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Tidskriftsartikel (refereegranskat)abstract
- The effects of oxytocin in the gastrointestinal tract are unclear. The aim of this study was to examine the effect of infusion of oxytocin on colonic motility and sensitivity in healthy women. Fourteen healthy women were investigated twice. A 6-channel perfusion catheter, with three recording points (2 cm apart) proximally and three recording points distally to a barostat balloon, was inserted to the splenic flexure. An intestinal feeding tube was placed in the mid-duodenum. A 90-min duodenal lipid infusion of 3 kcal min(-1) was administered. Thirty minutes after the start of the lipid infusion, the subject randomly received either 20 or 40 mU min(-1) of oxytocin, or isotonic saline as intravenous infusions for 90 min. Meanwhile, the colonic motility was recorded. During the last 30 min of oxytocin and saline infusion, the visceral sensitivity to balloon distensions was examined. During lipid infusion the number of antegrade contractions per hour was 0.7 +/- 0.3 after saline and 3.9 +/- 1.4 after oxytocin (P = 0.03), indicating more pronounced lumen-occlusive contractile activity after oxytocin administration. Some of these consisted of high-amplitude (> 103 mmHg in amplitude) antegrade contractions. Lipid infusion evoked a decrease of the balloon volume, reflecting increased colonic tone, but there was no difference between saline and oxytocin. Sensory thresholds did not differ significantly between saline and oxytocin. Infusion of oxytocin stimulates antegrade peristaltic contractions in stimulated colon in healthy women. The effects of oxytocin on colonic motor activity deserve to be further explored, especially in patients with colonic peristaltic dysfunction.
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| 10. |
- Schmidt, Peter Thelin, et al.
(författare)
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Methods to assess gastric motility and sensation
- 2008
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Ingår i: Scandinavian Journal of Gastroenterology. - London : Informa Healthcare. - 0036-5521 .- 1502-7708. ; 43:11, s. 1285-1295
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Tidskriftsartikel (refereegranskat)
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