Characterization of gut microbiota isolated from faeces from Crohn and celiac Disease patients and correlation with inflammatory cytokines

Abstract

In humans, over one hundred trillion microorganisms, mainly bacteria, colonize the oral-gastrointestinal tract, and the vast majority of these reside in the distal gut and was termed microbiota. The most important microbiota's contributions for the host include carbohydrates digestion and fermentation, B and K vitamin production, mucosal-associated lymphoid tissues development, immune responses polarization and prevent pathogens colonization. However, when this mutualistic relationship between host and microbiota is interrupted, the intestinal microbiota may cause or contribute to the development of inflammatory and autoimmune diseases. Therefore, the aim of this study is to characterize the intestinal microbiota isolated from faeces of patients with celiac and Crohn's disease correlate these data with inflammatory cytokines. All participants sign the informed consent and will respond to a social-epidemiological questionnaire. Stool samples will be taken by patients and controls or family in universal collectors, after control identification. Clinical data such as clinical form of the disease, clinical scores, extra-intestinal manifestations, presence of autoantibodies in celiac disease and drug treatment will be recorded. Bacterial DNA will be extracted from stool by using a commercial kit, and microbiota characterization will be performed by real-time PCR with primers for specific bacterial groups. The inflammatory cytokines, including TNF, IL-12, IL-6, IFN-gama, IL-17A and IL-22 will be quantified by ELISA assays. The data from microbiota characterization will be analyzed using Mann-Whitney t test and correlations of microbiota results with cytokines and clinical data will be assessed by Spearman test. We expect to find differences in microbiota composition isolated from patients compared with healthy subjects and possible correlations with plasma levels of inflammatory cytokines and clinical data. In Brazil, there are no studies evaluating dysbiosis in patients with celiac and Crohn' disease. Additional studies are necessary and possibly in the future, prevention of celiac and Crohn's disease may involve diet manipulation and microbiota modulation, as a way to control infections, autoimmunity and maintenance of homeostasis in the gastrointestinal tract.