| 1. |
- Vaga, S., et al.
(författare)
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Compositional and functional differences of the mucosal microbiota along the intestine of healthy individuals
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Gut mucosal microbes evolved closest to the host, developing specialized local communities. There is, however, insufficient knowledge of these communities as most studies have employed sequencing technologies to investigate faecal microbiota only. This work used shotgun metagenomics of mucosal biopsies to explore the microbial communities' compositions of terminal ileum and large intestine in 5 healthy individuals. Functional annotations and genome-scale metabolic modelling of selected species were then employed to identify local functional enrichments. While faecal metagenomics provided a good approximation of the average gut mucosal microbiome composition, mucosal biopsies allowed detecting the subtle variations of local microbial communities. Given their significant enrichment in the mucosal microbiota, we highlight the roles of Bacteroides species and describe the antimicrobial resistance biogeography along the intestine. We also detail which species, at which locations, are involved with the tryptophan/indole pathway, whose malfunctioning has been linked to pathologies including inflammatory bowel disease. Our study thus provides invaluable resources for investigating mechanisms connecting gut microbiota and host pathophysiology.
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| 2. |
- 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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| 3. |
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| 4. |
- Bonfiglio, Ferdinando, et al.
(författare)
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GWAS of stool frequency provides insights into gastrointestinal motility and irritable bowel syndrome
- 2021
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Ingår i: Cell Genomics. - Cambridge, MA, United States : Elsevier. - 2666-979X. ; 1:3
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Tidskriftsartikel (refereegranskat)abstract
- Gut dysmotility is associated with constipation, diarrhea, and functional gastrointestinal disorders like irritable bowel syndrome (IBS), although its molecular underpinnings are poorly characterized. We studied stool frequency (defined by the number of bowel movements per day, based on questionnaire data) as a proxy for gut motility in a GWAS meta-analysis including 167,875 individuals from UK Biobank and four smaller population-based cohorts. We identify 14 loci associated with stool frequency (p ≤ 5.0 × 10-8). Gene set and pathway analyses detected enrichment for genes involved in neurotransmitter/neuropeptide signaling and preferentially expressed in enteric motor neurons controlling peristalsis. PheWAS identified pleiotropic associations with dysmotility syndromes and the response to their pharmacological treatment. The genetic architecture of stool frequency correlates with that of IBS, and UK Biobank participants from the top 1% of stool frequency polygenic score distribution were associated with 5× higher risk of IBS with diarrhea. These findings pave the way for the identification of actionable pathological mechanisms in IBS and the dysmotility syndromes.
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| 5. |
- Molinder, Herdis, et al.
(författare)
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How individuals with the irritable bowel syndrome describe their own symptoms before formal diagnosis
- 2015
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Ingår i: Upsala Journal of Medical Sciences. - : Taylor & Francis. - 0300-9734 .- 2000-1967. ; 120:4, s. 276-279
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To investigate how individuals fulfilling the Rome II criteria for irritable bowel syndrome (IBS) spontaneously described their symptoms. Method: From a general population, 1,244 randomly sampled adults were asked to describe their gastrointestinal symptoms (if any) verbally, in their own words, at a semi-structured interview. Their own descriptions were sorted into five symptom clusters. The participants independently completed a written questionnaire (the Rome II Modular Questionnaire (RMIIMQ)). Results: A total of 601 participants reported at least one gastrointestinal symptom, and 128 had IBS according to the RMIIMQ. After exclusion of organic causes, previously diagnosed IBS, or additional gastrointestinal diagnosis, 81 participants with IBS according to RMIIMQ remained. Five participants (6%) described symptoms included in the full definition of IBS, but none fulfilled the Rome II criteria completely. Abdominal pain or other IBS-related symptoms were reported by 64 (79%), and 12 (15%) did not report any IBS-like symptom. Conclusion: Previously undiagnosed individuals, who fulfil criteria for Rome II-IBS, often express their complaints in words that do not fit into the current diagnostic criteria.
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| 6. |
- Wohlfarth, C., et al.
(författare)
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miR-16 and miR-103 impact 5-HT4 receptor signalling and correlate with symptom profile in irritable bowel syndrome
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Irritable bowel syndrome (IBS) is a gut-brain disorder involving alterations in intestinal sensitivity and motility. Serotonin 5-HT4 receptors are promising candidates in IBS pathophysiology since they regulate gut motor function and stool consistency, and targeted 5-HT4R selective drug intervention has been proven beneficial in subgroups of patients. We identified a single nucleotide polymorphism (SNP) (rs201253747) c.*61 T > C within the 5-HT4 receptor gene HTR4 to be predominantly present in diarrhoea-IBS patients (IBS-D). It affects a binding site for the miR-16 family and miR-103/miR-107 within the isoforms HTR4b/i and putatively impairs HTR4 expression. Subsequent miRNA-profiling revealed downregulation of miR-16 and miR-103 in the jejunum of IBS-D patients correlating with symptoms. In vitro assays confirmed expression regulation via three 3'UTR binding sites. The novel isoform HTR4b_2 lacking two of the three miRNA binding sites escapes miR-16/103/107 regulation in SNP carriers. We provide the first evidence that HTR4 expression is fine-tuned by miRNAs, and that this regulation is impaired either by the SNP c.*61 T > C or by diminished levels of miR-16 and miR-103 suggesting that HTR4 might be involved in the development of IBS-D.
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| 7. |
- 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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| 9. |
- Jones, Michael P., et al.
(författare)
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Gastrointestinal recall questionnaires compare poorly with prospective patient diaries for gastrointestinal symptoms : data from population and primary health centre samples
- 2019
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Ingår i: European Journal of Gastroenterology and Hepathology. - : Lippincott Williams & Wilkins. - 0954-691X .- 1473-5687. ; 31:2, s. 163-169
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Tidskriftsartikel (refereegranskat)abstract
- Background: Clinical understanding of gastrointestinal symptoms is commonly based on patient reports of symptom experience. For diagnosis and treatment choices to be appropriate, symptom reports need to be accurate. We examined the agreement between questionnaire recall and prospective diary enumeration of symptoms relevant to the irritable bowel syndrome.Patients and methods: Data are reported from a randomly selected general population sample (n=238) and also a primary healthcare centre (PHC) sample (n=503, 10 PHCs). All the patients completed the questionnaires, which included Rome III-qualifying irritable bowel syndrome items and a stool and symptom diary over either 7 or 14 days. Agreement between retrospective questionnaire reports and prospective diaries was evaluated.Results: Concordance between questionnaires and diaries was highest for the simple construct of the occurrence of abdominal pain, although after adjusting for possible chance, agreement was only moderate in the general population sample. More complex constructs, such as pain relieved by defecation, yielded poorer concordance. In general, concordance was stronger among PHC respondents than in the general population sample.Conclusion: Concordance between questionnaires and diaries was generally poor and related to the complexity of the symptom construct and the type of respondent. The information used to classify individuals based on patient self-report may be unreliable, and therefore, more effort is needed to develop data collection instruments.
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| 10. |
- Walter, Susanna, et al.
(författare)
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Measuring the impact of gastrointestinal inconvenience and symptoms on perceived health in the general population - validation of the Short Health Scale for gastrointestinal symptoms (SHS-GI)
- 2021
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 0036-5521 .- 1502-7708. ; 56:12, s. 1406-1463
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Tidskriftsartikel (refereegranskat)abstract
- Objectives Gastrointestinal (GI) symptoms are intimately related to our wellbeing. The Short Health Scale for GI symptoms (SHS-GI) is a simple questionnaire to measure the impact of GI inconvenience and symptoms on quality of life. The aim was to validate the SHS-GI in a general population sample and to compare it with SHS-data across different patient groups.Method A subsample of 170 participants from a population-based colonoscopy study completed the Rome II questionnaire, GI diaries, psychological questionnaire (hospital anxiety and depression scale) and SHS-GI at follow-up investigation. Psychometric properties of SHS-GI as an overall score were determined by performing a confirmatory factor analysis (CFA). Spearman correlation between SHS total score and symptoms was calculated in the general population sample. SHS-GI data was compared with SHS data from patients with inflammatory bowel disease (IBD) and fecal incontinence (FI).Results As expected, the general population rated their impact of GI inconvenience on quality of life as better than the patient populations in terms of all aspects of the SHS-GI. The CFA showed a good model fit meeting all fit criteria in the general population. Cronbach's alpha for the total scale was 0.80 in the general population sample and ranged from 0.72 in the FI sample to 0.88 and 0.89 in the IBD samples.Conclusions SHS-GI demonstrated appropriate psychometric properties in a sample of the normal population. We suggest that SHS-GI is a valid simple questionnaire suitable for measuring the impact of GI symptoms and inconvenience on quality of life in both general and patient populations.
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