| 1. |
- Björkqvist, Olle, 1993-, et al.
(författare)
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Alterations in the relative abundance of Faecalibacterium prausnitzii correlate with changes in fecal calprotectin in patients with ileal Crohn's disease : a longitudinal study
- 2019
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Ingår i: Scandinavian Journal of Gastroenterology. - : Taylor & Francis. - 0036-5521 .- 1502-7708. ; 54:4, s. 577-585
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Crohn's disease is characterized by a gut dysbiosis with decreased abundance of butyrate producers such as Faecalibacterium prausnitzii. Although F. prausnitzii secretes anti-inflammatory molecules, few studies have addressed the importance of F. prausnitzii in a longitudinal setting. We aimed to examine the relationship between temporal profiles of F. prausnitzii, the C. leptum group, overall butyrate production, and inflammatory activity.Material and methods: Fecal samples (n = 59) were collected every third month from nine patients with ileal Crohn's disease. The abundance of F. prausnitzii and C. leptum was quantified relative to the total amount of bacteria using quantitative-PCR. To assess butyrate production of gut microbiota, gene copy numbers of the butyryl-CoA:acetate-CoA transferase (BCoAT) gene were quantified by qPCR. The inflammatory activity was defined by fecal (f)-calprotectin.Results: No correlation between the relative abundance of F. prausnitzii, the C. leptum group, or copy numbers of the BCoAT gene, and f-calprotectin was observed in the total sample set. By analyzing alterations between consecutive samples, a negative correlation between changes in the relative abundance of F. prausnitzii and f-calprotectin was observed (R = -0.39; p = .009). Changes in C. leptum (R = -0.18, p = .23) and number of copies of the BCoAT gene (R = -0.12; p = .42) did not correlate with f-calprotectin.Conclusions: There was an inverse correlation between temporal changes in the relative abundance of F. prausnitzii, but not overall butyrate producing capacity, and changes in inflammatory activity in ileal Crohn's disease. These findings indicate that F. prausnitzii may play a role in gut homeostasis, even though causality is still to be demonstrated.
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| 2. |
- Hugerth, Luisa W, et al.
(författare)
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Assessment of In Vitro and In Silico Protocols for Sequence-Based Characterization of the Human Vaginal Microbiome
- 2020
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Ingår i: mSphere. - : American Society for Microbiology. - 2379-5042. ; 5:6
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Tidskriftsartikel (refereegranskat)abstract
- The vaginal microbiome has been connected to a wide range of health outcomes. This has led to a thriving research environment but also to the use of conflicting methodologies to study its microbial composition. Here, we systematically assessed best practices for the sequencing-based characterization of the human vaginal microbiome. As far as 16S rRNA gene sequencing is concerned, the V1-V3 region performed best in silico, but limitations of current sequencing technologies meant that the V3-V4 region performed equally well. Both approaches presented very good agreement with qPCR quantification of key taxa, provided that an appropriate bioinformatic pipeline was used. Shotgun metagenomic sequencing presents an interesting alternative to 16S rRNA gene amplification and sequencing but requires deeper sequencing and more bioinformatic expertise and infrastructure. We assessed different tools for the removal of host reads and the taxonomic annotation of metagenomic reads, including a new, easy-to-build and -use reference database of vaginal taxa. This curated database performed as well as the best-performing previously published strategies. Despite the many advantages of shotgun sequencing, none of the shotgun approaches assessed here agreed with the qPCR data as well as the 16S rRNA gene sequencing.IMPORTANCE The vaginal microbiome has been connected to various aspects of host health, including susceptibility to sexually transmitted infections as well as gynecological cancers and pregnancy outcomes. This has led to a thriving research environment but also to conflicting available methodologies, including many studies that do not report their molecular biological and bioinformatic methods in sufficient detail to be considered reproducible. This can lead to conflicting messages and delay progress from descriptive to intervention studies. By systematically assessing best practices for the characterization of the human vaginal microbiome, this study will enable past studies to be assessed more critically and assist future studies in the selection of appropriate methods for their specific research questions.
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| 3. |
- Ibrahim, Ahmed, et al.
(författare)
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Colitis-induced colorectal cancer and intestinal epithelial estrogen receptor beta impact gut microbiota diversity
- 2019
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Ingår i: International Journal of Cancer. - : John Wiley & Sons. - 0020-7136 .- 1097-0215. ; 144:12, s. 3086-3098
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Tidskriftsartikel (refereegranskat)abstract
- Chronic inflammation of the colon (colitis) is a risk factor for colorectal cancer (CRC). Hormone-replacement therapy reduces CRC incidences, and the estrogen receptor beta (ERβ/ESR2) has been implicated in this protection. Gut microbiota is altered in both colitis and CRC and may influence the severity of both. Here we test the hypothesis that intestinal ERβ impacts the gut microbiota. Mice with and without intestine-specific deletion of ERβ (ERβKOVil ) were generated using the Cre-LoxP system. Colitis and CRC were induced with a single intraperitoneal injection of azoxymethane (AOM) followed by administration of three cycles of dextran sulfate sodium (DSS) in drinking water. The microbiota population were characterized by high-throughput 16S rRNA gene sequencing of DNA extracted from fecal samples (N = 39). Differences in the microbiota due to AOM/DSS and absence of ERβ were identified through bioinformatic analyses of the 16S-Seq data, and the distribution of bacterial species was corroborated using qPCR. We demonstrate that colitis-induced CRC reduced the gut microbiota diversity and that loss of ERβ enhanced this process. Further, the Bacteroidetes genus Prevotellaceae_UCG_001 was overrepresented in AOM/DSS mice compared to untreated controls (3.5-fold, p = 0.004), and this was enhanced in females and in ERβKOVil mice. Overall, AOM/DSS enriched for microbiota impacting immune system diseases and metabolic functions, and lack of ERβ in combination with AOM/DSS enriched for microbiota impacting carbohydrate metabolism and cell motility, while reducing those impacting the endocrine system. Our data support that intestinal ERβ contributes to a more favorable microbiome that could attenuate CRC development.
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