Effects of Probiotics and Plant Components on Murine Experimental Colitis and Acute Liver Failure

University dissertation from Division of Food Technology Department of Food Technology, Engineering and Nutrition Lund University, Lund, Sweden

Abstract: Acute liver failure is accompanied by a high rate of bacterial septic complications. High portal level of lipopolysaccharide (LPS) can lead to a pronounced secretion by Kupffer cells of pro-inflammatory mediators which have been shown to be early and important mediators of liver injury. Pathogenesis of inflammatory bowel disease (IBD) is complex; involving environmental, genetic, microbial, and immunological factors and treatment should target components mediate the inflammatory response. Probiotics and the non-absorbable carbohydrates as well as the fruit or vegetable extracts with high content of antioxidants could decrease the severity of liver failure and colonic inflammation. Three animal models were used, liver injury induced by D-galactosamine or by D-galactosamine and endotoxin, and colitis-induced by dextran sulfate sodium (DSS). Our aim is to study the physiological effects of some bacterial strains with probiotic potential and plant components with potential beneficial effects, in relation to inflammation. The administration of certain strains of Lactobacillus and Bifidobacterium significantly improves the Disease Activity Index (DAI) in the DSS colitis model, reduces bacterial translocation and Enterobacteriaceae count in the colon. L. plantarum DSM 9843, Bifidobacterium sp. 3B1, and B. infantis DSM 15158 seem to have the best effect. Oral administration of bifidobacteria and raftilose synergy 1 in an experimental colitis produced an anti-inflammatory effect (reducing DAI, bacterial translocation, MPO, IL-1? and MDA). Major differences in effect were observed between the two tested strains of B. infantis with regard to MDA and succinic acid concentration as well as bacterial translocation rate in synbiotic combinations, B. infantis DSM 15159 seemed superior. L. plantarum strains (DSM 9843 and DSM 15313) and rose hip supplementation attenuates the inflammation, improves the intestinal barrier function and the antioxidative capacity, and facilitates the recovery of the inflamed tissue in an experimental colitis, through amelioration of the production of the inflammatory mediators as well as the production of different substances . The administration of L. plantarum DSM 15313, L. fermentum 35D and blueberry, alone and in combination, significantly improves the colitis disease activity index, reduces bacterial translocation to extra-intestinal sites and reduces inflammation. All test-strains except L. paracasei DSM 13434 inhibited bacterial translocation to the liver. L. paracasei translocated to the liver, and also failed to decrease the load of Enterobacteriaceae in cecum. L. plantarum DSM 9843 and B. infantis DSM 15158 were most effective at protecting the liver during injury. Thus, there are major effectual differences between strains/species. In contrast, the phylogenetically most diverse strains, L. plantarum DSM 9843 and B. infantis DSM 15158 exercised the same good effects. Blueberry and probiotics exert protective effects on acute liver injury to different extents. They reduced the hepatocytes liver injury, the inflammation and the pro-inflammatory cytokines, and improved the barrier functions and antioxidant activity. In conclusion the effects of the probiotics and prebiotics on the intestinal micro-ecology are important and it produces a balance in the microbial environment with a reduction in the potentially pathogenic organisms. Their effects could be through direct and indirect effects on microflora ecology, barrier functions, cellular proliferation and antioxidant activity as well as the production of different substances. All that could affect the local and systemic immunity and lipid peroxidation. Thus probiotics and prebiotics may exert their effects via diverse mechanisms and there are effectual differences between probiotic strains.

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