Browsing by Subject "IBD"
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(2019)Inflammatory bowel disease (IBD) is a globally increasing chronic disease, for which the pathogenesis still is unclear. The most common subtypes of IBD are Crohn’s disease (CD) and ulcerative colitis (UC). It is widely known that, in addition to the genetics, an altered immune response against the gut microbiome plays an important role in the development of the disease. For the IBD patients, to whom conventional medication is not sufficient, the TNF-α blocker infliximab, is given. However, about one third of the patients receiving infliximab treatment, do not respond to the drug, or lose response over time. Since there to this day are no reliable diagnostic markers available, the finding of such is of great importance. The goal of this study was to investigate possible markers for drug response in the gut mycobiota composition of IBD patients. The gut mycobiota composition of 72 IBD patients receiving infliximab was studied by MiSeq sequencing of fungal DNA from fecal samples, collected during one year. The sequencing data was analyzed using the mare package in R. In addition, anti-Saccharomyces cerevisiae antibody (ASCA) concentrations were measured from baseline serum samples by ELISA. Finally, calprotectin concentrations were measured from baseline and twelve weeks post infliximab serum samples by ELISA to study whether serum samples could be used instead of fecal samples for measuring calprotectin values. Results show an increase of the Candida and Spiromyces genera in the gut mycobiota of non-responding patients at baseline. At all timepoints, the Spiromyces genus was observed at a higher abundance, compared to the group of patients responding well or partially to the medication. Interestingly, the increase of Candida was seen only in Crohn’s disease patients, when looking at the composition at all timepoints. ASCA values did not differ between the response groups. The serum calprotectin values did not correlate with fecal calprotectin, and serum calprotectin can thus not be used as a marker of gut inflammation. In conclusion, the gut mycobiota can offer predictive markers for drug response prediction to infliximab in IBD patients, which can with further studies offer a clinical diagnostic tool for prediction of drug response.
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(2011)The human gastrointestinal tract (GIT) contains a complex microbiota which starts to develop after birth. Various factors such as age, health, diet and medication affect the composition of the GIT microbiota. The number and types of bacteria are different in each part of the GIT, but most of the bacteria are anaerobic. In faeces the number of bacterial cells is as high as 1011-1012 cfu/ml. The normal intestinal microbiota is essential for intestinal development, protein and carbohydrate metabolisms, and protection against pathogens. Sulphate-reducing bacteria (SRB) are typically anaerobic bacteria which use sulphate as a terminal electron acceptor to produce sulphide in their metabolism. Sulphate-reducing bacteria are widespread in all ecosystems including fresh water and marine sediments but are also present in the GIT. Most of SRB species are Gram-negative and they can use more than hundred compounds as electron donors. Dissimilatory sulphite reduction (dsrAB) gene is essential in sulphate reduction. dsrAB-gene encodes the enzyme called dissimilatory sulphite reductase, which is a key enzyme in the reduction of sulphite to sulphide. Recent findings suggest that SRB may have a role in human diseases, e.g. in periodontitis and inflammatory bowel disease (IBD). Connection between these disorders and SRB may be due to the highly toxic hydrogen sulphide. The aim of this study was to develop PCR-DGGE and qPCR methods for monitoring of sulphate-reducing bacteria from human faecal microbiota. In this study we used dsrAB-gene specific primers, which were used successfully in previous environmental microbiology studies. Previously published dsrAB-specific primers were used for PCR-DGGE. However, besides positive controls, two negative controls also amplified regardless of the modifications on temperature, amplification times, primers and MgCl2 concentration. In qPCR, specific and sensitive amplification was attained by using dsrA-gene specific primers. When the samples from paediatric patients with IBD (Crohn’s disease and ulcerative colitis) and healthy children were amplified, no differences were found between different disease groups. However there was a statistically significant difference (P <0.05) between the paediatric patients with Crohn’s disease who were on remission and those patients who’s disease was active (number of SRB; active<remission).
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(2018)The literature review of the study focused on intestinal microbiota and the connection between its imbalance and Inflammatory Bowel Disease (IBD). Specific focus was on communication between microbes and human host through congenital immune defense. The purpose of the experimental phase was to research in vitro, the adherence of the human Lactobacillus rhamnosus GG, Bifidobacterium bifidum strain DSM20456 and the Lactobacillus acidophilus strain LAB20 of canine and the EPS mutant strain LAB20 to Caco-2 and HT-29 cell lines and mucus. The adhesion method was based on bacterial cells that were marked with tritium. The next experiment was whether the bacteria could reduce inflammatory response in the LPS-induced HT-29 cell line. HT-29 cells produced inflammatory mediator IL-8, and its concentration was measured by collecting the supernatant above the cells and measuring the IL-8 concentration with the ELISA-method. In conclusion, the effect of adhesin proteins SpaC and BopA as anti-inflammatory components was tested. L. rhamnosus GG, B. bifidum DSM20456 and L. acidophilus LAB20 adhered to the HT-29, Caro-2 cells of epithelial cell lines and to mucus. LAB20 EPS mutants did not adhere to mucus at all, so the EPS-construction of the strain LAB20 would appear to be relevant to the bacteria’s adherence. L. rhamnosus GG, B. bifidum DSM20456 and L. acidophilus LAB20 strains showed anti-inflammatory properties. They significantly reduced IL-8 yield in the LPS-induced inflammatory response in the HT-29 cell line. L. acidophilus LAB20 significantly reduced the yield of IL-8 in one test, and therefore the result of this study is indicative. LAB20 EPS mutants did not cut the IL-8 yield, so EPS structures may be responsible for the anti-inflammatory feature of the strain LAB20. Bacteria SpaC- and BopA-adhesin proteins showed pro-inflammatory properties, i.e. an inflammatory response in the HT-29 cell line. The results showed that L. rhamnosus GG, B. bifidum DSM20456 and L. acidophilus LAB20 strains have adhesion and anti-inflammatory properties. The LAB20 is a new and potential probiotic for canines. B. bifidum also showed anti-inflammatory properties, so it could also act as a palliative for IBD. The SpaC and BopA adhesin proteins did not show any anti-inflammatory effects, but they still proved to be stimulating host's immune defense, which plays an important role in the host's immune system regulation. EPS structures may convey the LAB20 adhesion to mucus and anti-inflammatory properties.
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