Browsing by Subject "dysbiosis"

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  • Giaretta, Paula R; Rech, Raquel R; Guard, Blake C; Blake, Amanda B; Blick, Anna K; Steiner, Jörg M.; Lidbury, Jonathan A; Cook, Audrey K; Hanifeh, Mohsen; Spillmann, Thomas; Kilpinen, Susanne; Syrjä, Pernilla; Suchodolski, Jan (2018)
    Background Objective Intestinal absorption of bile acids is mediated by the apical sodium-dependent bile acid transporter (ASBT). Fecal bile acid dysmetabolism has been reported in dogs with chronic inflammatory enteropathy (CIE). Characterization of ASBT distribution along the intestinal tract of control dogs and comparison to dogs with CIE. Animals Methods Twenty-four dogs with CIE and 11 control dogs. The ASBT mRNA and protein expression were assessed using RNA in situ hybridization and immunohistochemistry, respectively. The concentrations of fecal bile acids were measured by gas chromatography-mass spectrometry. The fecal microbiota dysbiosis index was assessed with a quantitative polymerase chain reaction panel. Results Conclusions and Clinical Importance In control dogs, ASBT mRNA expression was observed in enterocytes in all analyzed intestinal segments, with highest expression in the ileum. The ASBT protein expression was restricted to enterocytes in the ileum, cecum, and colon. Dogs with CIE had significantly decreased expression of ASBT protein in the ileum (P = .001), which was negatively correlated with histopathological score (rho = -0.40; P-corr = .049). Additionally, dogs with CIE had a significantly increased percentage of primary bile acids in feces compared to controls (P = .04). The fecal dysbiosis index was significantly higher in dogs with CIE than in control dogs (P = .01). These findings indicate that ileal protein expression of ASBT is downregulated in dogs with CIE. This change may be linked to the inflammatory process, intestinal dysbiosis, and fecal bile acid dysmetabolism observed in these patients.
  • Hetemäki, Iivo; Jian, Ching; Laakso, Saila Marita; Mäkitie, Outi; Pajari, Anne-Maria; Vos de, Willem Meindert; Arstila, Petteri; Salonen, Anne (2021)
    Backgrounds and Aims: APECED is a rare autoimmune disease caused by mutations in the Autoimmune Regulator gene. A significant proportion of patients also have gastrointestinal symptoms, including malabsorption, chronic diarrhea, and obstipation. The pathological background of the gastrointestinal symptoms remains incompletely understood and involves multiple factors, with autoimmunity being the most common underlying cause. Patients with APECED have increased immune responses against gut commensals. Our objective was to evaluate whether the intestinal microbiota composition, predicted functions or fungal abundance differ between Finnish patients with APECED and healthy controls, and whether these associate to the patients’ clinical phenotype and gastrointestinal symptoms. Methods: DNA was isolated from fecal samples from 15 patients with APECED (median age 46.4 years) together with 15 samples from body mass index matched healthy controls. DNA samples were subjected to analysis of the gut microbiota using 16S rRNA gene amplicon sequencing, imputed metagenomics using the PICRUSt2 algorithm, and quantitative PCR for fungi. Extensive correlations of the microbiota with patient characteristics were determined. Results: Analysis of gut microbiota indicated that both alpha- and beta-diversity were altered in patients with APECED compared to healthy controls. The fraction of Faecalibacterium was reduced in patients with APECED while that of Atopobium spp. and several gram-negative genera previously implicated in biofilm formation, e.g. Veillonella, Prevotella, Megasphaera and Heamophilus, were increased in parallel to lipopolysaccharide (LPS) synthesis in imputed metagenomics. The differences in gut microbiota were linked to patient characteristics, especially the presence of anti-Saccharomyces cerevisiae antibodies (ASCA) and severity of gastrointestinal symptoms. Conclusions: Gut microbiota of patients with APECED is altered and enriched with predominantly gram-negative bacterial taxa that may promote biofilm formation and lead to increased exposure to LPS in the patients. The most pronounced alterations in the microbiota were associated with more severe gastrointestinal symptoms.
  • Honkanen, Jarno; Vuorela, Arja; Muthas, Daniel; Orivuori, Laura; Luopajärvi, Kristiina; Tejesvi, Mysore Vishakante Gowda; Lavrinienko, Anton; Pirttilä, Anna Maria; Fogarty, Christopher L.; Härkönen, Taina; Ilonen, Jorma; Ruohtula, Terhi; Knip, Mikael; Koskimäki, Janne J.; Vaarala, Outi (2020)
    Although gut bacterial dysbiosis is recognized as a regulator of beta-cell autoimmunity, no data is available on fungal dysbiosis in the children at the risk of type 1 diabetes (T1D). We hypothesized that the co-occurrence of fungal and bacterial dysbiosis contributes to the intestinal inflammation and autoimmune destruction of insulin-producing beta-cells in T1D. Fecal and blood samples were collected from 26 children tested positive for at least one diabetes-associated autoantibody (IAA, GADA, IA-2A or ICA) and matched autoantibody-negative children with HLA-conferred susceptibility to T1D (matched for HLA-DQB1 haplotype, age, gender and early childhood nutrition). Bacterial 16S and fungal ITS2 sequencing, and analyses of the markers of intestinal inflammation, namely fecal human beta-defensin-2 (HBD2), calprotectin and secretory total IgA, were performed. Anti-Saccharomyces cerevisiae antibodies (ASCA) and circulating cytokines, IFNG, IL-17 and IL-22, were studied. After these analyses, the children were followed for development of clinical T1D (median 8 years and 8 months). Nine autoantibody positive children were diagnosed with T1D, whereas none of the autoantibody negative children developed T1D during the follow-up. Fungal dysbiosis, characterized by high abundance of fecal Saccharomyces and Candida, was found in the progressors, i.e., children with beta-cell autoimmunity who during the follow-up progressed to clinical T1D. These children showed also bacterial dysbiosis, i.e., increased Bacteroidales and Clostridiales ratio, which was, however, found also in the non-progressors, and is thus a common nominator in the children with beta-cell autoimmunity. Furthermore, the progressors showed markers of intestinal inflammation detected as increased levels of fecal HBD2 and ASCA IgG to fungal antigens. We conclude that the fungal and bacterial dysbiosis, and intestinal inflammation are associated with the development of T1D in children with beta-cell autoimmunity.
  • Freitag, Tobias L.; Hartikainen, Anna; Jouhten, Hanne; Sahl, Cecilia; Meri, Seppo; Anttila, Veli-Jukka; Mattila, Eero; Arkkila, Perttu; Jalanka, Jonna; Satokari, Reetta (2019)
    Fecal microbiota transplantation (FMT) is an effective therapy for recurrent Clostridioides difficile infection (rCDI) and is also considered a potential treatment for a wide range of intestinal and systemic diseases. FMT corrects the microbial dysbiosis associated with rCDI, and the engraftment of donor microbiota is likely to play a key role in treatment efficacy. For disease indications other than rCDI, FMT treatment efficacy has been moderate. This may be partly due to stronger resilience of resident host microbiota in patients who do not suffer from rCDI. In rCDI, patients typically have undergone several antibiotic treatments prior to FMT, depleting the microbiota. In this study, we addressed the effect of broad-spectrum antibiotics (Ab) as a pre-treatment to FMT on the engraftment of donor microbiota in recipients. We conducted a pre-clinical study of FMT between two healthy mouse strains, Balb/c as donors and C57BL/6 as recipients, to perform FMT within the same species and to mimic interindividual FMT between human donors and patients. Microbiota composition was assessed with high-throughput 16S rDNA amplicon sequencing. The microbiota of Balb/c and C57BL/6 mice differed significantly, which allowed for the assessment of microbiota transplantation from the donor strain to the recipient. Our results showed that Ab-treatment depleted microbiota in C57BL/6 recipient mice prior to FMT. The diversity of microbiota did not recover spontaneously to baseline levels during 8 weeks after Ab-treatment, but was restored already at 2 weeks in mice receiving FMT. Interestingly, pre-treatment with antibiotics prior to FMT did not increase the overall similarity of the recipient's microbiota to that of the donor's, as compared with mice receiving FMT without Ab-treatment. Pre-treatment with Ab improved the establishment of only a few donor-derived taxa, such as Bifidobacterium, in the recipients, thus having a minor effect on the engraftment of donor microbiota in FMT. In conclusion, pre-treatment with broad-spectrum antibiotics did not improve the overall engraftment of donor microbiota, but did improve the engraftment of specific taxa. These results may inform future therapeutic studies of FMT.
  • Hiippala, Kaisa; Jouhten, Hanne; Ronkainen, Aki; Hartikainen, Anna; Kainulainen, Veera; Jalanka, Jonna; Satokari, Reetta (2018)
    The intestinal microbiota, composed of pro- and anti-inflammatory microbes, has an essential role in maintaining gut homeostasis and functionality. An overly hygienic lifestyle, consumption of processed and fiber-poor foods, or antibiotics are major factors modulating the microbiota and possibly leading to longstanding dysbiosis. Dysbiotic microbiota is characterized to have altered composition, reduced diversity and stability, as well as increased levels of lipopolysaccharide-containing, proinflammatory bacteria. Specific commensal species as novel probiotics, so-called next-generation probiotics, could restore the intestinal health by means of attenuating inflammation and strengthening the epithelial barrier. In this review we summarize the latest findings considering the beneficial effects of the promising commensals across all major intestinal phyla. These include the already well-known bifidobacteria, which use extracellular structures or secreted substances to promote intestinal health. Faecalibacterium prausnitzii, Roseburia intestinalis, and Eubacterium hallii metabolize dietary fibers as major short-chain fatty acid producers providing energy sources for enterocytes and achieving anti-inflammatory effects in the gut. Akkermansia muciniphila exerts beneficial action in metabolic diseases and fortifies the barrier function. The health-promoting effects of Bacteroides species are relatively recently discovered with the findings of excreted immunomodulatory molecules. These promising, unconventional probiotics could be a part of biotherapeutic strategies in the future.
  • Pakola, Ida (Helsingfors universitet, 2017)
    Dysbiosis is a condition where gut microbiota’s diversity and stability are decreased and the composition of bacterial community is altered as compared to healthy microbiota. Dysbiosis can cause serious harm to host’s immune system and it is linked to inflammatory bowel diseases (IBD). In IBD, the immune system is disturbed and there is a constant inflammation of the gut. Currently IBD is treated by antibiotics and immunomodulators, but it could be preferable to use treatments which aim to restore a healthy microbiota, because dysbiosis has been found to play role in maintaining the continuous inflammation in gut. One potential treatment to restore the healthy microbiota is bacterial therapy. Anti-inflammatory bacterial species of healthy gut could be potential components of bacterial therapy product for IBD-targeted drug. The aim of this study was to isolate spore-forming anti-inflammatory bacteria from fecal material that had been used previously in fecal microbiota transplantation. The aim was to isolate intestinal bacteria, which could be used as a treatment for IBD in the future. Anti-inflammatory properties of spore-formers were an object of interest because the aim was to study could bacterial spores be used in IBD-targeted bacterial therapy. For isolating bacterial spores from the sample, two selection methods were used, ethanol-treatment and heat shock. Treated samples were cultivated on six different media. Bacterial isolates were picked from the plates followed by anti-inflammatory screening to select potentially anti-inflammatory isolates. In anti-inflammatory screening the effect of an isolate on lipopolysaccharide induced IL-8-production of HT-29-cell line was measured. Potentially anti-inflammatory isolates were purified to pure cultures followed by sequencing of their 16S rRNA gene (rDNA). Anti-inflammatory effect of pure cultures on HT-29-cells were tested again with three parallel reactions. Selection methods didn’t work out as well as expected. Based on the 16S rDNA sequences of bacterial populations collected from different media, two treatments managed to select a good portion of Firmicutes, but none of the potentially anti-inflammatory pure culture isolates were spore-formers. According to the 16S rDNA sequences most of the purified strains belonged to the genera Staphylococcus or Enterococcus. Only a small proportion of the potentially anti-inflammatory isolates were confirmed as anti-inflammatory. In this study, six anti-inflammatory Enterococcus faecalis -strains were isolated and purified. In the future, these strains need to be studied further to assess their potential in bacteriotherapeutic applications and clinical use. The methods and results of this study can be used to further optimize the procedures to isolate various intestinal bacteria.