Prolonged Intake of Luvos Healing Earth does not alter the Composition of the Gut Microbiota in Patients with Diarrhea-predominant Irritable Bowel Syndrome and Healthy Controls.

BACKGROUND AND AIMS: The mineral compound Luvos Healing Earth (LHE) is a commercially available remedy empirically used for a variety of gastrointestinal disorders. The aim of this study was to investigate the possible effect of prolonged LHE therapy on gut microbiota in healthy individuals and in patients with diarrhea-predominant irritable bowel syndrome (IBS-D). METHODS: In this prospective exploratory study, a total of 20 participants, including 12 healthy controls and 8 patients with IBS-D, received treatment with LHE (Magenfein Granulat, 1 sachet bid) for 6 weeks. Fecal samples were collected for microbiota analysis in the morning fasting state at regular intervals at 6 different timepoints: 2 weeks before starting therapy (Screen), and every 2 weeks during LHE therapy (V0-V3). Additionally, a follow-up visit was scheduled 4 weeks after the end of treatment (V4). Microbiota analysis was performed using the GA-map® Dysbiosis Test Lx v2. Dysbiosis Index, bacterial diversity, as well as the balance or imbalance of functionally important bacteria were assessed. RESULTS: The microbiota analysis revealed an overlap in gut microbiota profiles between healthy controls and patients with IBS-D. Bacterial communities were consistently stable during the entire treatment period, and no significant variations in composition were observed 4 weeks after the end of the therapeutic intervention. There was a remarkable stability of microbiota profiles over time within each individual and a high inter-individual variation. The majority of fecal samples exhibited profiles, reflecting an eubiotic state, with no significant changes in dysbiosis index, functional bacteria profiles, or bacterial diversity. CONCLUSION: Our findings indicate intraindividual resilience of microbiota consortia during the entire study period. Prolonged intake of LHE does not cause significant alterations in fecal microbiota profiles in healthy controls and patients with IBS-D. Luvos Healing Earth does not affect the stability of gut microbial diversity and bacterial functions.

Feed microbiome: confounding factor affecting fish gut microbiome studies.

There is an increasing interest in the impact of feed on the fish gut microbiome. Most of the studies are based on sequencing the bacterial housekeeping gene 16S rRNA from extracted total DNA, including resident and non-resident live bacteria as well as dead bacteria. It has not been a common practice to include the feed as control, although it contains various nutritious ingredients that microorganisms can use before or after feed preparation. Thus, study designs using digesta as a proxy for the intestinal microbiome raise the concern that composition of the gut microbiome might be biased by carry-over of microbial DNA from the feed itself. Here we report analysis of 15 feeds and representative intestinal digesta of Atlantic salmon (Salmo salar) from five independent case studies. This allowed us to identify "feed microbiomes" that were microbially diverse and shared taxa with digesta microbiomes. Digesta-specific microbiomes were identified, though they were mainly enriched by a few taxa, such as Mycoplasma and Ruminococcaceae. Overall, findings are consistent with a model wherein gut microbial profiles are to a different degree influenced by bacterial DNA present in the feed itself through a "feed microbiome" carry-over effect.

Gut microbiota profiles and the role of anti-CdtB and anti-vinculin antibodies in patients with functional gastrointestinal disorders (FGID).

BACKGROUND: Distinct faecal microbiota profiles are reported to be associated with various subtypes of IBS. Circulating antibodies to cytolethal distending toxin B (CdtB) and vinculin are proposed as biomarkers to identify post-infectious IBS. The aim of our study was to analyse serum levels of anti-CdtB and anti-vinculin antibodies in patients with different functional gastrointestinal disorders (FGID) and their correlation with the composition of faecal microbiome. METHODS: The study cohort comprised 65 prospectively recruited individuals: 15 with diarrhoea-type-IBS (IBS-D), 13 with constipation-type-IBS (IBS-C), 15 with functional dyspepsia (FD) and 22 healthy controls. FGID subgroups were defined according to Rome III criteria. Serum levels of anti-CdtB and anti-vinculin antibodies were measured by ELISA. Faecal microbiome composition analysis and assessment of dysbiosis were performed by GA-map® Dysbiosis Test. RESULTS: Positivity rate either for anti-CdtB or anti-vinculin antibodies was higher in the IBS-C group (76.9%) compared to IBS-D (40.0%), FD (60%) and healthy (63.6%) groups. Dysbiosis was more frequent in subjects positive for anti-CdtB antibodies and in IBS-C patients, who showed an increased amount of opportunistic/pro-inflammatory bacteria and reduced gut protective bacteria. IBS-C patients showed a high inter-individual variation of bacterial communities compared to other FGID subgroups and healthy individuals, whereas microbial profiles of patients with IBS-D and FD were overlapping with those of healthy controls. No bacteria markers showed significant differences between FGID subgroups and healthy controls. CONCLUSION: Neither anti-CdtB/anti-vinculin antibodies nor faecal microbial profiles allowed to discriminate between specific FGID subgroups. Dysbiosis was more frequent in patients presenting with anti-CdtB antibodies and in IBS-C patients.

Resolving the complexity of vitellogenins and their receptors in the tetraploid Atlantic salmon (Salmo salar): Ancient origin of the phosvitin-less VtgC in chondrichthyean fishes.

Egg yolk proteins are mainly derived from vitellogenin (Vtg), and serve as essential nutrients during early development in oviparous organisms. Vertebrate Vtgs are predominantly synthesized in the liver of maturing females, and are internalized by the oocyte after binding to specific surface receptors (VtgR). Here, we clarify the evolutionary history of vertebrate Vtgs, including the teleost VtgC, which lacks phosvitin, and investigate the repertoire of Vtgs and VtgRs in the tetraploid Atlantic salmon (Salmo salar). Conserved synteny of the vtg genes in elephant fish (Callorhinchus milii) strongly indicates that the vtg gene cluster was present in the ancestor of tetrapods and ray-finned fish. The shortened phosvitin in the VtgC ortholog of this chondrichthyean fish may have resulted from early truncation events that eventually allowed the total disappearance of phosvitin in teleost VtgC. In contrast, the tandem-duplicated VtgCs identified in the spotted gar (Lepisosteus oculatus) both contain the phosvitin domain. The Atlantic salmon genome harbors four vtg genes encoding the complete VtgAsa1, phosvitin-less VtgC, and truncated VtgAsb proteins; vtgAsa2 is a pseudogene. The three vtg genes were mainly expressed in the liver of maturing females, and the vtgAsa1 transcript predominated prior to spawning. The splice variant lacking the O-linked sugar domain dominated ovarian expression of vtgr1 and vtgr2. Strongly increased vtgAsa1 expression during vitellogenesis contrasted with the peaks of vtgr1 and vtgr2 in the previtellogenic oocytes, which gradually decreased over the same period. Recycling of the oocyte VtgRs is probably not sufficient to maintain receptor number during vitellogenesis.