IN VITRO SELECTION OF A PROBIOTIC POTENTIALLY USEFULL IN THERAPY OF INFLAMMATORY BOWEL DISEASES


Fonteyn F., Didderen I., Thonart P., Louis E.
Department of gastroenterology, CHU of Liège, Sart Tilman, B35, 4000 Liège, Belgium

Introduction:
Inflammatory bowel disease (IBD) is a group of inflammatory conditions of the gastrointestinal tract including ulcerative colitis and Crohn’s disease. The exact causes of these immune-mediated inflammatory diseases are unclear. It is thought that several factors may play a part, including immune dysregulation against host intestinal microflora.
Probiotics have been tested in several trials. Results have generally been disappointing with the exception of the treatment of pouchitis with VSL-3 a broad mix of highly dosed probiotics and E coli Nissle 1917 to treat ulcerative colitis.
The previous inconsistent results of probiotics approach may partly be linked to insufficient characterisation of the strain used leading to an inappropriate choice of these strains. The aim of this study is to evaluate a range of lactic acid bacteria (LAB) for the development of a combination of probiotic strains with demonstrated properties.

Methods:
Sixteen Lactobacillus strains, Lactococcus lactis and Streptococcus thermophilus coming from THT s.a. collection (Isnes, Belgium) were tested for acid resistance, bile salts resistance, adhesion of Caco-2 cell and cytokines production by whole blood cell cultures from patients with IBD.
Statistical analysis of results was performed.

Results:
A large variability was observed among the strains tested with regard to their viability after incubation at low pH, their ability to grow in the presence of bile salts and adhere to human intestinal epithelial Caco-2 cells.
The acid resistance of strains Lb. rhamnosus LR02 and Lb. plantarum LP03 is 51.91% ± 39.61 and 81.53% ± 9.81 respectively at pH2.5 after 3 hours of incubation. These same strains tolerate the maximum concentration of 20 g/L of bile salts for growth. The highest levels of adherence to human intestinal epithelial Caco-2 cells have been observed with four strains including LP03.
LR02, Lb. casei LCa and LP03 also significantly increased production of IL-10 cytokine from whole blood cell cultures from patients with IBD.
The combination of LCa, LP03 and LR02 strains, named ProbioTer, is characterized by good adhesive properties (30 ± 15 bacteria by microscopic field) and induced IL-10 (p<0.001) and IL-17 (p<0.01) concentrations significantly higher than observed with LPS.

Discussion:
Despite the development of medications to treat Crohn’s disease and the ulcerative colitis, there are currently no medical cures for IBD. LAB have emerged as serious candidates to fill a role as therapeutic option. Nevertheless, the evaluation of potential probiotics to influence the human immune system has to be considered carefully.
Validation of probiotic contents in commercial products is a preliminary step to the realization of a clinical trial and is needed to generate data confirming the benefits of using these products.
Our results demonstrate that ProbioTer might have beneficial effect on IBD, suggesting a possibility for a clinical trial.

Keywords: Lactobacillus casei, Lactobacillus plantarum, Lactobacillus rhamnosus, Probiotics, Acid resistance, Bile salts, Caco-2 cells, Cytokines

Citation:
Fonteyn F., Didderen I., Thonart P., Louis E. (2016). In vitro selection of a probiotic potentially usefull in therapy of inflammatory bowel diseases.  Conference Proceedings of IPC2016. Paper presented at the International Scientific Conference on Probiotics and Prebiotics, Budapest (p. 92.). IPC2016

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