Ulcerative colitis (UC) is characterized by chronic inflammation of the colonic mucosa. Administration of dextran sulfate sodium (DSS) to animals is a frequently used model to mimic human colitis. Deregulation of the immune response to the enteric microflora or pathogens as well as increased intestinal permeability have been proposed as disease-driving mechanisms. To enlarge the understanding of the pathogenesis, we have studied the effect of DSS on the immune system and gut microbiota in mice. Intestinal inflammation was verified through histological evaluation and myeloperoxidase activity. Immunological changes were assessed by flow cytometry in spleen, Peyer′s patches and mesenteric lymph nodes and through multiplex cytokine profiling. In addition, quantification of the total amount of bacteria on colonic mucosa as well as the total amount of lactobacilli, Akkermansia, Desulfovibrio and Enterobacteriaceae was performed by the use of quantitative PCR. Diversity and community structure were analysed by terminal restriction fragment length polymorphism (T-RFLP) patterns, and principal component analysis was utilized on immunological and T-RFLP patterns. DSS-induced colitis show clinical and histological similarities to UC. The composition of the colonic microflora was profoundly changed and correlated with several alterations of the immune system. The results demonstrate a relationship between multiple immunological changes and alterations of the gut microbiota after DSS administration. These data highlight and improve the definition of the immunological basis of the disease and suggest a role for dysregulation of the gut microbiota in the pathogenesis of colitis.

• Antioxidant properties and phenols in plant materials not usually used were studied. • Folin-Ciocalteu, FRAP and ABTS measures correlate with different phenol compounds. • Large differences in antioxidant properties were found between and within species. • Sea buckthorn and black currant leaves had the highest antioxidant capacity.

Two Lactobacillus strains have proven anti-inflammatory properties by reducing pro-inflammatory responses to antigens. This randomized double-blind placebo-controlled trial tested the hypothesis that L. plantarum HEAL9 and L. paracasei 8700:2 suppress ongoing celiac disease autoimmunity in genetically at risk children on a gluten-containing diet in a longitudinally screening study for celiac disease. Seventy-eight children with celiac disease autoimmunity participated of whom 40 received 10¹⁰ CFU/day of L. plantarum HEAL9 and L. paracasei 8700:2 (probiotic group) and 38 children maltodextrin (placebo group) for six months. Blood samples were drawn at zero, three and six months and phenotyping of peripheral blood lymphocytes and IgA and IgG autoantibodies against tissue transglutaminase (tTG) were measured. In the placebo group, naïve CD45RA+ Th cells decreased (p = 0.002) whereas effector and memory CD45RO+ Th cells increased (p = 0.003). In contrast, populations of cells expressing CD4+CD25^highCD45RO+CCR4+ increased in the placebo group (p = 0.001). Changes between the groups were observed for NK cells (p = 0.038) and NKT cells (p = 0.008). Median levels of IgA-tTG decreased more significantly over time in the probiotic (p = 0.013) than in the placebo (p = 0.043) group whereas the opposite was true for IgG-tTG (p = 0.062 respective p = 0.008). In conclusion, daily oral administration of L. plantarum HEAL9 and L. paracasei 8700:2 modulate the peripheral immune response in children with celiac disease autoimmunity.

Objective. To clarify the effect ofLactobacillus plantarum299v on the salivary cortisol and salivary IgA levels in young adults under examination stress.Design. Forty-one students with an upcoming academic exam were included in a randomized double-blind, placebo-controlled study. The probiotic bacteria or the placebo product was administered in capsules once a day during 14 days. Saliva was collected and a perceived stress test was filled out at each sampling occasion. Saliva was collected for cortisol analysis by Electrochemiluminescence Immunoassay (ECLI) and salivary IgA was analysed by Enzyme-Linked Immunosorbent Assay (ELISA). Abundance of lactobacilli was evaluated by cultivation of saliva on selective medium and identification ofL. plantarum299v was done on randomly selected colonies by a random amplification of polymorphic DNA (RAPD) typing.Results. A significant difference in cortisol levels was found between the treatment group and the placebo group (P<0.05), together with a significant increase in levels of lactobacilli in the treatment group compared with the placebo group (P<0.001). No significant changes were found for salivary IgA.Conclusion. A probiotic bacterium with ability to reduce symptoms of irritable bowel syndrome (IBS) prohibited increased levels of the stress marker cortisol during the examination period. The registration number of the study isNCT02974894, and the study is registered at ClinicalTrials.gov.

Customer demands for fresh salads are increasing, but leafy green vegetables have also been linked to food‐borne illness due to pathogens such as Escherichia coli O157:H7. As a safety measure, consumers often wash leafy vegetables in water before consumption. In this study, we analyzed the efficiency of household washing to reduce the bacterial content. Romaine lettuce and ready‐to‐eat mixed salad were washed several times in flowing water at different rates and by immersing the leaves in water. Lettuce was also inoculated with E. coli before washing. Only washing in a high flow rate (8 L/min) resulted in statistically significant reductions (p < .05), “Total aerobic count” was reduced by 80%, and Enterobacteriaceae count was reduced by 68% after the first rinse. The number of contaminating E. coli was not significantly reduced. The dominating part of the culturable microbiota of the washed lettuce was identified by rRNA 16S sequencing of randomly picked colonies. The majority belonged to Pseudomonadaceae, but isolates from Enterobacteriaceae and Staphylococcaceaceae were also frequently found. This study shows the inefficiency of tap water washing methods available for the consumer when it comes to removal of bacteria from lettuce. Even after washing, the lettuce contained high levels of bacteria that in a high dose and under certain circumstances may constitute a health risk.

The primary focus of this review is a discussion regarding in vitro media for colon release, but we also give a brief overview of colon delivery and the colon microbiota as a baseline for this discussion. The large intestine is colonized by a vast number of bacteria, approximately 10¹² per gram of intestinal content. The microbial community in the colon is complex and there is still much that is unknown about its composition and the activity of the microbiome. However, it is evident that this complex microbiota will affect the release from oral formulations targeting the colon. This includes the release of active drug substances, food supplements, and live microorganisms, such as probiotic bacteria and bacteria used for microbiota transplantations. Currently, there are no standardized colon release media, but researchers employ in vitro models representing the colon ranging from reasonable simple systems with adjusted pH with or without key enzymes to the use of fecal samples. In this review, we present the pros and cons for different existing in vitro models. Furthermore, we summarize the current knowledge of the colonic microbiota composition which is of importance to the fermentation capacity of carbohydrates and suggest a strategy to choose bacteria for a new more standardized in vitro dissolution medium for the colon.