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Although it is now known that the human body is colonized by a wide variety of microbial populations in different parts (such as the mouth, pharynx and respiratory system, the skin, the gastro- and urogenital tracts), many effects of the complex interactions between the human host and microbial symbionts are still not completely understood. The dysbiosis of the gastrointestinal tract microbiota is considered to be one of the most important contributing factors in the development of many gastrointestinal diseases such as inflammatory bowel disease, irritable bowel syndrome and colorectal cancer, as well as systemic diseases like obesity, diabetes, atherosclerosis and non-alcoholic fatty liver disease. Fecal microbial transplantations appear to be promising therapies for dysbiosis-associated diseases; however, probiotic microorganisms have been growing in popularity due to increasing numbers of studies proving that certain strains present health promoting properties, among them the beneficial balance of the intestinal microbiota. Inflammatory bowel diseases and obesity are the pathologies in which there are more studies showing this beneficial association using animal models and even in human clinical trials. In this review, the association of the human gut microbiota and human health will be discussed along with the benefits that probiotics can confer on this symbiotic activity and on the prevention or treatment of associated diseases. Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina Fil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina

Inflammatory bowel diseases affect the quality of life of many people through the world. Previous studies demonstrated the anti-inflammatory potential of a yoghurt prepared with a pool of candidate probiotic strains of Lactobacillus (L.) delbrueckii subsp. bulgaricus and Streptococcus (S.) thermophilus from the CERELA Culture Collection. Considering that the probiotic effects are strain specific, the aim of this work was to select from this yoghurt, the LAB strains related to this anti-inflammatory effect and prove their potential in vitro and in vivo. M&M: L. delbrueckii subsp. bulgaricus (CRL861, 863, 864, 866, 869, 871, 872 and 887) and S. thermophilus (CRL806 and 807) were grown separately to obtain the fermented milks (FM). The in vitro anti-inflammatory capacity of each FM was studied in co-culture with mononuclear cells isolated from Peyer’s patches of healthy mice, by evaluating the cytokines IFNg and IL-10 in the supernatants. The in vitro selected FM were administered to healthy mice and to mice inoculated with TNBS (colitis model). Pro-inflammatory cytokines (IFNg, IL-17) and the regulatory cytokine IL-10 were evaluated in their intestines. Results: The in vitro studies demonstrated that the cocultures with FMs obtained with S. thermophilus CRL807 and L. bulgaricus 864 showed increased IL10/IFNγ ratios. This IL10/IFNγ ratio also increased in the intestinal fluids of healthy mice given these FMs. These mice also increased the ratio of IL10+ cells/IL17+ cells in their

INTRODUCTION: Antitumour activity is one of the health-promoting effects attributed to the lactic acid bacteria and their products of fermentation. Previous studies in mice demonstrated that bioactive compounds released in milk fermented by Lactobacillus helveticus R389 contribute to its immunoenhancing and antitumour properties. The aim of the present work was to study the effects of the consumption of milk fermented by L. helveticus R389 or its proteolytic-deficient variant, L. helveticus L89, on a murine hormone-dependent breast cancer model. METHODS: Mice were fed with milk fermented by L. helveticus R389 or L. helveticus L89, during 2 or 7 days. The tumour control group received no special feeding. At the end of the feeding period, the mice were challenged by a subcutaneous injection of tumour cells in the mammary gland. Four days post-injection, the mice received fermented milk on a cyclical basis. The rate of tumour development and the cytokines in serum, mammary gland tissue and tumour-isolated cells were monitored. Bcl-2-positive cells in mammary glands and cellular apoptosis in tumour tissue were also studied. RESULTS: Seven days of cyclical administration of milk fermented by either bacterial strain delayed or stopped the tumour development. Cytokines demonstrated that L. helveticus R389 modulated the immune response challenged by the tumour. IL-10 and IL-4 were increased in all the samples from this group. In comparison with the tumour control, all test groups showed a decrease of IL-6, a cytokine involved in oestrogen synthesis. Seven days of cyclical feeding with milk fermented by L. helveticus R389 produced an increase in the number of apoptotic cells, compared with all other groups. CONCLUSION: This study demonstrated that 7 days of cyclical administration of milk fermented by both strains of L. helveticus diminishes tumour growth, stimulating an antitumour immune response. Compounds released during milk fermentation with L. helveticus R389 would be implicated in its immunoregulatory capacity on the immune response in mammary glands and tumour, which were correlated with the cytokines found at the systemic level. The milk fermented by L. helveticus R389 was able to modulate the relationship between immune and endocrine systems (by IL-6 diminution), which is very important in oestrogen-dependent tumour and induced cellular apoptosis. Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina. Université de Moncton; Canadá Fil: Matar, Chantal. Université de Moncton; Canadá Fil: LeBlanc, Nicole. Université de Moncton; Canadá Fil: Perdigon, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina

Lactic acid bacteria (LAB) found in numerous fermented products can interact with the gut associated lymphoid tissue increasing antibody (principally secretory IgA) production. IgA secreting cells can repopulate not only the lamina propria but also they can go to other distant sites such as bronchus, urogenital tract and mammary glands a phenomenon known as the IgA cycle. Later studies have shown that both B cells of other isotypes and T cells from Peyer's patches also exhibit gut-seeking properties. The aim of this study was to study the effect of different feeding periods of L. casei CRL 431 on the interaction with the immune cells in Peyer's patches studying the migration of not only the IgA+ cells, but also other immune cells (T lymphocytes) to other mucosal sites such as bronchus and mammary glands. BALB/c mice were fed with L. casei CRL 431 during 2, 5 or 7 days. At the end of the feeding period, the mice were killed and the small intestine, the lung and the mammary glands were removed. IgA+ cells and CD4+ and CD8+ T lymphocytes were counted in tissue slices using direct immunofluorescence. IgA+ cells increased in the intestine samples taken after 7 days of LAB feeding. In mammary gland and lung tissues, IgA+ cells increased after five days of feeding. CD4+ and CD8+ T lymphocytes were not able to migrate to sites distant from the intestine and their number did not increase in the lamina propria of the small intestine. L. casei CRL 431 was able to stimulate the IgA cycle without proliferation of T population. These results allow us to suggest that this LAB could be used as oral adjuvant to protect mucosal surfaces from intestinal and respiratory diseases, and would also be useful as an adjuvant to protect against mammary glands pathologies such as cancer.

Lactic acid bacteria (LAB) are the most commonly used microorganisms in probiotic products and it is known that these LAB enhanced the immune response and increase resistance to neoplasia and infections. In previous studies using an experimental model of BALB/c mice it was demonstrated that a cyclical diet of yoghurt given to animals previously injected with the carcinogen 1,2 dimethylhydrazine (DMH) inhibited the development of colorectal carcinoma. The animals showed an inflammatory response prior to the development of the tumour, which was diminished with the yoghurt feeding. We examined the immunoregulatory and antiinflammatory mechanisms involved in the inhibition of tumour growth by yoghurt and compared with the mechanisms of a non-steroidal antiinflammatory drug (Indomethacin). Five experimental groups (BALB/c mice) were used in this study: 1) DMH group, injected with 1,2 dimethylhydrazine weekly for 10 weeks. 2) DMH-yoghurt group, yoghurt was supplemented 10 days followed by inoculation with DMH. After tumour induction yoghurt was given every 10 days for six months. 3) Only yoghurt given during six months following the same schedule (yoghurt control. 4) DMH-indomethacin group. After tumour induction, animals were treated with indomethacin, injected cyclically. 5) Non-treatment control group fed with a conventional balanced diet. We studied IgA secreting cells and CD4+ and CD8+ T cells in the large intestine of mice fed long term with yoghurt and others treated with indomethacin. TNFα, INFγ cytokines, Bcl2 protein and iNOS enzyme production was also measured We observed an increase in the number of IgA-secreting cells but not in the CD4+ and CD8+ cells in the mice fed long term with yoghurt. Indomethacin treated mice showed high values of all these cellular populations. Mice injected with indomethacin did not show increased levels of the proinflammatory cytokine TNFα and INFγ. These cytokines were increased in DMH and DMH plus yoghurt groups. iNOS enzyme determinations were increased in DMH and DMH plus indomethacin group. These results coincided with the inflammatory response observed in the histological findings. Bcl-2 protein was increased in mice fed long term with yoghurt. We suggest that the immune mechanisms by which yoghurt operates would be different to those induced with the antiinflammatory drug indomethacin. Yoghurt activated the production of cytokines that could exert a regulation of the immune response by apoptosis induced by TNFα. We conclude that yoghurt down modulate the immune response and exert its antitumour activity by its antiinflammatory activity, a mechanism that is different with that of the antiinflammatory indomethacin.

Background: Fibronectin Binding Protein A (FnBPA) is an invasin from Staphylococcus aureus that allows this pathogen to internalize into eukaryote cells. It was previously demonstrated that recombinant Lactococcus lactis expressing FnBPA were invasive and able to transfer a plasmid to eukaryotic cells in vitro and in vivo. In this study, the invasivity of recombinant strains of Lactococcus lactis that express FnBPA under the control of its constitutive promoter or driven by the strong nisin inducible expression system (NICE) were studied.Results: It was demonstrated that the nisA promoter allows an increase of FnBPA expression on the surface of Lactococcus lactis surface, as shown by flow cytometry, which subsequently enhanced internalization and plasmid transfer properties in vitro in Caco2 cells and Bone Marrow Dendritic Cells. In vivo, the use of nisA promoter increase the plasmid transfer in cells of both the small and large intestine of mice.Conclusion: FnBPA expression at the surface of recombinant L. lactis is positively correlated to internalization and DNA transfer properties. The recombinant strains of L. lactis that expresses FnBPA under the control of the nisin inducible expression system could thus be considered as an improved tool in the field of DNA transfer. Fil: Almeida, Juliana F.. Institut National de la Recherche Agronomique; Francia. Institut des sciences et industries du vivant et de l; Francia Fil: Mariat, Denis. Institut National de la Recherche Agronomique; Francia. Institut des sciences et industries du vivant et de l; Francia Fil: Azevedo, Vasco. Universidade Federal Do Minas Gerais; Fil: Miyoshi, Anderson. Universidade Federal Do Minas Gerais; Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina Fil: del Carmen, Silvina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina Fil: Martin, Rebeca. Institut National de la Recherche Agronomique; Francia. Institut des sciences et industries du vivant et de l; Francia Fil: Langella, Philippe. Institut National de la Recherche Agronomique; Francia. Institut des sciences et industries du vivant et de l; Francia Fil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina Fil: Chatel, Jean Marc. Institut National de la Recherche Agronomique; Francia. Institut des sciences et industries du vivant et de l; Francia

The population tends to consume foods that in addition to their nutritional values can offer some benefits to their health. There are many epidemiological evidences and research studies in animal models suggesting that diet plays an important role in breast cancer prevention or progression. This review summarized some of the relevant researches about nutrition and cancer during the last years, especially in breast cancer. The analysis of probiotics and fermented products containing lactic acid bacteria in cancer prevention and/or treatment was especially discussed. It was observed that a balance of fatty acids similar to those of traditional Mediterranean diet, the consumption of fruits and vegetables, dietary fiber intake, vitamin supplementation are, along with the intake of probiotic products, the most extensively studied by the negative association to breast cancer risk. The consumption of probiotics and fermented products containing lactic acid bacteria was associated to reduce breast cancer risk in some epidemiological studies. The use of animal models showed the modulation of the host?s immune response as one of the important effects associated to the benefices observed with most probiotics. However; future assays in human are very important before the medical community can accept the addition of probiotic or fermented milks containing lactic acid bacteria as supplements for cancer patients. Fil: Aragón, Félix Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina Fil: Perdigon, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Microbiología; Argentina Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina

In recent years, the number of functional dairy products enriched with live probiotic microorganisms has increased exponentially since it is know that these can confer health benefits to the host. One of the most important mechanisms by which probiotics can act in the prevention of disease is through their capacity to produce antimicrobial substances such as lactic acid and bacteriocins. These can prevent the growth of pathogenic microorganisms in foods, meaning that probiotics could therefore be used as a tool to prevent foodborne diseases. Currently, some foods are supplemented with prebiotics (non-digestible oligosaccharides) in order to favor the growth of selected probiotics in the gastrointestinal tract. We discuss the current and future uses of synbiotics (probiotics and prebiotics) in order to increase the safety of food. Fil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Pinheiro de Souza Oliveira, Ricardo. Universidade de Sao Paulo; Brasil Fil: Todorov, Svetoslav Dimitrov. Universidade de Sao Paulo; Brasil

The aims of this study were to develop strains of lactic acid bacteria (LAB) having both immunomodulatory and antioxidant properties and to evaluate their anti-inflammatory effects both in vitro , in different cellular models, and in vivo , in a mouse model of colitis. Different Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus strains were cocultured with primary cultures of mononuclear cells. Analysis of the pro- and anti-inflammatory cytokines secreted by these cells after coincubation with candidate bacteria revealed that L. delbrueckii subsp. bulgaricus CRL 864 and S. thermophilus CRL 807 display the highest anti-inflammatory profiles in vitro . Moreover, these results were confirmed in vivo by the determination of the cytokine profiles in large intestine samples of mice fed with these strains. S. thermophilus CRL 807 was then transformed with two different plasmids harboring the genes encoding catalase (CAT) or superoxide dismutase (SOD) antioxidant enzymes, and the anti-inflammatory effects of recombinant streptococci were evaluated in a mouse model of colitis induced by trinitrobenzenesulfonic acid (TNBS). Our results showed a decrease in weight loss, lower liver microbial translocation, lower macroscopic and microscopic damage scores, and modulation of the cytokine production in the large intestines of mice treated with either CAT- or SOD-producing streptococci compared to those in mice treated with the wild-type strain or control mice without any treatment. Furthermore, the greatest anti-inflammatory activity was observed in mice receiving a mixture of both CAT- and SOD-producing streptococci. The addition of L. delbrueckii subsp. bulgaricus CRL 864 to this mixture did not improve their beneficial effects. These findings show that genetically engineering a candidate bacterium (e.g., S. thermophilus CRL 807) with intrinsic immunomodulatory properties by introducing a gene expressing an antioxidant enzyme enhances its anti-inflammatory activities.

Probiotic microorganisms and fermented foods containing lactic acid bacteria have been growing in popularity due to increasing numbers of studies proving that certain strains present health promoting properties, among them the prevention or treatment in the early stages of some types of cancers. There are many reports about the anticarcinogenic effect ofprobiotic strains and fermented products against intestinal and non intestinal tumors. Different mechanisms of action can be involved in these beneficial effects, being the modulation of the host?s immunity one of the most important properties reported using in vitro assays and also in animal models. However, there are few human trials in which the application of probiotics as biotherapeutics against cancer were tested. These assays are very important before the medical community can accept the addition of probiotic or fermented milks as supplements for cancer patients. This review summarizes some of the relevant research with probiotics and fermented products containing lactic acid bacteria in cancer prevention and / or treatment with emphasis on the possible mechanisms involved. Colon cancer is one of the types of cancer for which there are more researches and will be discussed separately from the non intestinal tumours. Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); Argentina

Background: Oral treatment with Lactococcus (L.) lactis strains secreting the anti-inflammatory cytokine IL-10 has previously shown success as a therapy for inflammatory bowel diseases (IBD). Goals: Our aim was to compare the protective effects of IL-10, delivered by recombinant lactoccoci using two novel expression systems, in a murine colitis model mimicking the relapsing nature of IBD. The first system is based on a Stress-Inducible Controlled Expression (SICE) system for the production and delivery of heterologous proteins at mucosal surfaces and the second allows the delivery to the host cells of an il-10 cDNA cassette, harbored in a eukaryotic DNA expression vector (pValac). Study: Colitis was induced in female BALB/c mice by intrarectal injection of 2,4,6-trinitrobenzenesulphonic acid (TNBS). Mice that recovered received one of the bacteria treatments or saline solution orally during 14 days. Colitis was reactivated 25 days after the first TNBS injection with a second TNBS challenge. Three days after colitis reactivation, cytokine profiles and inflammation in colon samples were evaluated. Results: Animals (N=9) receiving L. lactis strains secreting IL-10 using SICE system or delivering pValac:il-10 plasmid showed lower weight loss (p

Lactic acid bacteria (LAB) represent a heterogeneous group of microorganisms that are naturally present in many foods and possess a wide range of therapeutic properties.

Lactic acid bacteria (LAB) represent a heterogeneous group of microorganisms naturally present in many foods and those have proved to be effective mucosal delivery vectors. Moreover, some specific strains of LAB exert beneficial properties (known as probiotic effect) on both human and animal health. Although probiotic effects are strain-specific traits, it is theoretically possible, using genetic engineering techniques, to design strains that can exert a variety of beneficial properties. During the two past decades, a large variety of therapeutic molecules has been successfully expressed in LAB, and although this field has been largely reviewed in recent years, approximately 20 new publications appear each year. Thus, the aim of this minireview is not to extensively assess the entire literature but to update progress made within the last 2 years regarding the use of the model LAB Lactococcus lactis and certain species of lactobacilli as live recombinant vectors for the development of new safe mucosal vaccine. Fil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia Para Lactobacilos (i); Argentina; Universidad Nacional de Tucuman. Facultad de Medicina. Departamento de Investigacion. Catedra de Metodologia de la Invest.cientifica; Argentina; Fil: Aubry, Camille. Institut National de la Recherche Agronomique; Francia; Fil: Cortes-Perez, Naima G.. Institut National de la Recherche Agronomique; Francia; Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia Para Lactobacilos (i); Argentina; Fil: Vergnolle, Nathalie. INSERM; Francia; Centre National de la Recherche Scientifique; Francia; Universite Paul Sabatier; Francia; Fil: Langella, Philippe. Institut National de la Recherche Agronomique; Francia; Fil: Azevedo, Vasco. Universidade Federal Do Minas Gerais; Brasil; Fil: Chatel, Jean-Marc. Institut National de la Recherche Agronomique; Francia; Fil: Miyoshi, Anderson. Universidade Federal Do Minas Gerais; Brasil; Fil: Berúdez-Humarán, Luis G.. Institut National de la Recherche Agronomique; Francia

Probiotic microorganisms have a positive impact on health and improve the host immune system. Studies in animals and humans have demonstrated that probiotic bacteria can immunomodulate the systemic and mucosal immunity, protect against enteropathogens or offer antitumoral activities, and improve health in immunosuppression by malnutrition or drug therapy.

Lactobacillus delbrueckii ssp. lactis CRL 581, a thermophilic lactic acid bacterium used as a starter culture for the manufacture of several fermented dairy products, possesses an efficient proteolytic system that is able to release a series of potentially bioactive peptides (i.e., antihypertensive and phosphopeptides) from alpha- and beta-caseins. Considering the potential beneficial health effects of the peptides released by L. delbrueckii ssp. lactis CRL 581 from milk proteins, the aim of this work was to analyze the anti-mutagenic and anti-inflammatory properties of the casein hydrolysates generated by the cell envelope-associated proteinase of this bacterium. The ability of alpha- and beta-casein hydrolysates to suppress the mutagenesis of a direct-acting mutagen 4-nitroquinoline-N-oxide on Salmonella typhimurium TA 98 and TA 100 increased concomitantly with the time of casein hydrolysis. The anti-inflammatory effect of the beta-casein hydrolysate was evaluated using a trinitrobenzene sulfonic acid (TNBS)-induced Crohns disease murine model. The hydrolysate was administered to mice 10 d before the intrarectal inoculation of TNBS. The mice that received beta-casein hydrolysate previously to TNBS showed decreased mortality rates, faster recovery of initial body weight loss, less microbial translocation to the liver, decreased beta-glucuronidase and myeloperoxidase activities in the gut, and decreased colonic macroscopic and microscopic damage compared with the animals that did not receive this hydrolysate. In addition, beta-casein hydrolysate exerted a beneficial effect on acute intestinal inflammation by increased interleukin 10 and decreased IFN-´gamma production in the gut. Our findings demonstrated the health promoting attributes of the milk products fermented by L. delbrueckii ssp. lactis CRL 581 and open up new opportunities for developing novel functional foods. Fil: Espeche Turbay, Maria Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina Fil: Perdigon, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Savoy, Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina Fil: Hebert, Elvira Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentina

Interleukin-10 (IL-10) is the most important anti-inflammatory cytokine at intestinal level, and its absence is involved in inflammatory bowel diseases. However, oral treatment with IL-10 is difficult because of its low survival in the gastrointestinal tract and systemic treatments lead to undesirable side effects. The aim of this paper was to evaluate the anti-inflammatory effect of the administration of milks fermented by Lactococcus lactis strains that produce IL-10 under the control of the xylose-inducible expression system using a trinitrobenzenesulfonic acid-induced colitis murine model. Mice that received milks fermented by L. lactis strains producing IL-10 in the cytoplasm (Cyt strain) or secreted to the product (Sec strain) showed lower damage scores in their large intestines, decreased IFN-γ levels in their intestinal fluids and lower microbial translocation to liver, compared to mice receiving milk fermented by the wild-type strain or those not receiving any treatment. The results obtained in this study show that the employment of fermented milks as a new form of administration of IL-10-producing L. lactisis effective in the prevention of inflammatory bowel disease in a murine model.

Inflammatory bowel disease (IBD) is a term used to describe a group of intestinal disorders in which inflammation is a major feature. Although rare forms of IBD exist, these diseases normally pertain to ulcerative colitis (UC) (Head & Jurenka, 2003) and Crohn’s disease (CD) (Baumgart & Sandborn, 2007). There is evidence that these do not represent distinct conditions but rather are the same disease with shared etiological factors (Price, 1992); however, clinical manifestations (such as the exact location of the pathology or the affected individual’s immunological and constitutional endowment) are distinctive between both. Despite many years of study, the exact etiology and pathogenesis of these disorders remain unclear but great advances have been made using experimental animal models and have provided insights into the complex, multi-factorial processes and mechanisms that can result in chronic intestinal inflammation (Elson & Weaver, 2003). The aim of this chapter is to present an overview of the current expanding knowledge of the mechanisms by which lactic acid bacteria and other probiotic microorganisms participate in the prevention and treatment of IBD and how genetic engineering techniques can be used to improve their effectiveness or create novel therapeutic strains. In the following sections, the mechanisms by which these beneficial microorganisms exert their therapeutic effects, which include changes in the gut microbiota, stimulation of the host immune responses, enhancement of intestinal barrier function and reduction of the oxidative stress due to their antioxidant properties will be discussed. Fil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: del Carmen, Silvina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Alvarenga Lima, Fernanda. Universidade Federal de Minas Gerais; Brasil Fil: Zurita Turk, Meritxell. Universidade Federal de Minas Gerais; Brasil Fil: Miyoshi, Anderson. Universidade Federal de Minas Gerais; Brasil Fil: Azevedo, Vasco. Universidade Federal de Minas Gerais; Brasil Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina

The aim was to evaluate both the ability of yeast strains to survive and bind AFB(1) under ruminant gastrointestinal conditions and the effect of these yeast strains on ruminal fermentation. Yeast viability was studied under simulated gastrointestinal conditions. AFB(1) binding ability was evaluated at different pH values as present in the ruminant gastrointestinal tract. The effect of yeast strains on cellulose digestion and volatile fatty acids production by ruminal bacteria was also evaluated. All yeast strains were able to survive under gastrointestinal conditions and to adsorb AFB(1) at the different pH assayed. The strain RC016 showed the highest binding percentage at the three tested pH. The number of cellulolytic bacteria in ruminal fluid increased in the presence of RC008 and RC016 yeast strains. The concentration of acetate and propionate after ruminal fermentation increased with the addition of RC008 and RC016 strains; this effect was less significant with RC009 strain. Strains RC008 and RC016 are potential probiotic to be included in animal feed: they help to increase fibber digestibility and could reduce AFB(1 )bioavailability in the gastrointestinal tract. Viable S. cerevisiae RC008 and RC016 strains with both probiotic and mycotoxins adsorption properties could be used as feed additives in ruminant feedstuff.

Background: Malnutrition affects the immune response, causing a decrease of defence mechanisms and making the host more susceptible to infections. Probiotics can reconstitute the intestinal mucosa and stimulate local and systemic immunity. The aim of this work was evaluate the effects of a probiotic fermented milk as a complement of a re-nutrition diet, on the recovery of the intestinal barrier, and mucosal and systemic immune functions in a murine model of non-severe protein-energy-malnutrition. Its potential protection against Salmonella enterica serovar Typhimurium (S. Typhimurium) infection was also analyzed.Methods: Mice were undernourished and divided into 3 groups according to the dietary supplement received during re-nutrition (milk, probiotic fermented milk or its bacterial free supernatant) and compared to well-nourished and malnourished mice. They were sacrificed previous to the re-nutrition and 5 days post re-nutrition. The phagocytic activity of macrophages from spleen and peritoneum and the changes in the intestinal histology and microbiota were evaluated. Different immune cell populations and cytokine productions were analyzed in the small intestine tissues. The effect of the re-nutrition supplements on the systemic immunity using OVA antigen and against an infection with S. Typhimurium was also studied.Results: Probiotic fermented milk was the most effective re-nutrition diet that improved the intestinal microbiota. Its administration also increased the number of IgA+ cells, macrophages and dendritic cells. The production of different cytokine (IFN-γ, TNF-α, IL-12) by these cells and the phagocytic activity in peritoneum and spleen was also increased. This re-nutrition diet also stimulated the systemic immune response against OVA antigen which was diminished after the malnutrition period and also improved the host response against S. Typhimurium, decreasing the spread of pathogenic bacteria to the liver and the spleen. The importance of the metabolites released during milk fermentation was also demonstrated through the analysis of the bacterial free supernatant obtained from the probiotic fermented milk, but the whole product showed the best effects in the parameters evaluated in this study.Conclusions: The administration of probiotic fermented milk as a dietary supplement during the re-nutrition process in a murine immunodeficiency model by malnutrition could be a good adjuvant diet to improve the gut and systemic immune response for the protection against Salmonella infection. Fil: Maldonado Galdeano, María Carolina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Novotny Núñez, Ivanna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Carmuega, Esteban. Nutritia; Argentina Fil: Weill, Ricardo. DANONE. Departamento de Investigación y Desarrollo; Argentina Fil: Perdigon, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina

Crohn's disease and ulcerative colitis, two forms of inflammatory bowel disease, are important problems in industrialized countries. The complete etiology of these two diseases is still unknown but likely involves genetic, environmental, and immunological factors. The aim of the present work was to determine whether the anti-inflammatory effects reported for yoghurt in acute trinitrobenzene sulfonic acid-induced intestinal inflammation in mice also could prevent or attenuate the recurrent intestinal inflammation, thus maintaining remission. The innate response also was evaluated through participation of Toll-like receptors (TLRs) and the analysis of T-cell populations to determine the effects of yoghurt in an acute inflammatory bowel disease model. Yoghurt exerted a beneficial effect on acute intestinal inflammation by regulating T-cell expansion and modulating the expression of TLRs, with decrease of TLR4+ and increase of TLR9z cells. The anti-inflammatory effect of yoghurt also was demonstrated in a recurrent inflammation model. Yoghurt administration during the remission phase prevented the recurrence of inflammation without producing undesirable side effects. The yoghurt effect may be mediated by increased interleukin 10 production and changes in intestinal microbiota. Fil: Chaves, Analia Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Perdigon, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Microbiologia. Cátedra de Inmunología; Argentina Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina

Background Diarrheal infections caused by Salmonella, are one of the major causes of childhood morbidity and mortality in developing countries. Salmonella causes various diseases that range from mild gastroenteritis to enteric fever, depending on the serovar involved, infective dose, species, age and immune status of the host. Probiotics are proposed as an attractive alternative possibility in the prevention against this pathogen infection. Previously we demonstrated that continuous Lactobacillus casei CRL 431 administration to BALB/c mice before and after challenge with Salmonella enterica serovar Typhimurium (S. Typhimurium) decreased the severity of Salmonella infection. The aim of the present work was to deep into the knowledge about how this probiotic bacterium exerts its effect, by assessing its impact on the expression and secretion of pro-inflammatory (TNFα, IFNγ) and anti-inflammatory (IL-10) cytokines in the inductor and effector sites of the gut immune response, and analyzing toll-like receptor (TLR2, TLR4, TLR5 and TLR9) expressions in both healthy and infected mice. Results Probiotic administration to healthy mice increased the expression of TLR2, TLR4 and TLR9 and improved the production and secretion of TNFα, IFNγ and IL-10 in the inductor sites of the gut immune response (Peyer's patches). Post infection, the continuous probiotic administration, before and after Salmonella challenge, protected the host by modulating the inflammatory response, mainly in the immune effector site of the gut, decreasing TNFα and increasing IFNγ, IL-6 and IL-10 production in the lamina propria of the small intestine. Conclusions The oral administration of L. casei CRL 431 induces variations in the cytokine profile and in the TLRs expression previous and also after the challenge with S. Typhimurium. These changes show some of the immune mechanisms implicated in the protective effect of this probiotic strain against S. Typhimurium, providing an alternative way to reduce the severity of the infection.

Lactic acid bacteria (LAB) represent a heterogeneous group of microorganisms that are naturally present in many foods and possess a wide range of therapeutic properties. The aim of this paper is to present an overview of the current expanding knowledge of one of the mechanisms by which LAB and other probiotic microorganisms participate in the prevention and treatment of gastrointestinal inflammatory disease through their immune-modulating properties. A special emphasis will be placed on the critical role of the anti-inflammatory cytokine IL-10, and a brief overview of the uses of genetically engineered LAB that produce this important immune response mediator will also be discussed. Thus, this paper will demonstrate the critical role that IL-10 plays in gastrointestinal inflammatory diseases and how probiotics could be used in their treatment.

Lactic acid bacteria (LAB) represent a heterogeneous group of microorganisms that are naturally present in many foods and possess a wide range of therapeutic properties. The aim of this paper is to present an overview of the current expanding knowledge of one of the mechanisms by which LAB and other probiotic microorganisms participate in the prevention and treatment of gastrointestinal inflammatory disease through their immune-modulating properties. A special emphasis will be placed on the critical role of the anti-inflammatory cytokine IL-10, and a brief overview of the uses of genetically engineered LAB that produce this important immune response mediator will also be discussed. Thus, this paper will demonstrate the critical role that IL-10 plays in gastrointestinal inflammatory diseases and how probiotics could be used in their treatment. Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: del Carmen, Silvina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Zurita Turk, Meritxell. Universidade Federal de Minas Gerais; Brasil Fil: Santos Rocha, Clarissa. Universidade Federal de Minas Gerais; Brasil Fil: van de Guchte, Maarten. Institut National de la Recherche Agronomique; Francia Fil: Azevedo, Vasco. Universidade Federal de Minas Gerais; Brasil Fil: Miyoshi, Anderson. Universidade Federal de Minas Gerais; Brasil Fil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina

Lactic acid bacteria (LAB) represent a heterogeneous group of microorganisms that are naturally present in many foods and possess a wide range of therapeutic properties. The aim of this paper is to present an overview of the current expanding knowledge of the mechanisms by which LAB and other probiotic microorganisms participate in the prevention and treatment of inflammatory bowel diseases. These include changes in the gut microbiota, stimulation of the host immune responses, and reduction of the oxidative stress due to their antioxidant properties. A brief overview of the uses of genetically engineered LAB that produce either antioxidant enzymes (such as catalase and superoxide dismutase) or anti-inflammatory cytokines (such as IL-10) will also be discussed. This paper will show that probiotics should be considered in treatment protocols of IBD since they provide many beneficial effects and can enhance the effectiveness of traditional used medicines.

Prebiotics are non-digestible but fermentable oligosaccharides that can influence the composition and the activity of some intestinal bacteria to promote the health of the host. Smallanthus sonchifolius (yacon) contains beta-1,2-oligofructans as the main saccharides and its roots are consumed in South American countries. The aim of the study was to evaluate the prebiotic property of yacon root flour. Its influence on the intestinal microbiota and gut immune system were evaluated using a mice model. The results show the prebiotic effects of yacon root flour, stimulating the growth of bifidobacteria and lactobacilli and the intestinal immune system with increases in IgA and different cytokines. Cells from the innate response were mainly involved in the effect of yacon root flour. T cells were also activated and able to induce IL-10 and IFNg production. The long term administration of yacon root flour maintained the intestinal homeostasis without inflammatory effect regulated mainly through IL-10 and IL-4 regulatory cytokines. Fil: Bibas Bonet, María Eugenia. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: Mesón, Oscar Enrique. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Dogi, Cecilia Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Chaves, Analia Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Kortsarz González, Alejandra María. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Laboratorio de Investigaciones Ecológicas de las Yungas; Argentina Fil: Grau, Alfredo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Laboratorio de Investigaciones Ecológicas de las Yungas; Argentina Fil: Perdigon, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina

The intestinal ecosystem contains a normal microbiota, non-immune cells and immune cells associated with the intestinal mucosa. The mechanisms involved in the modulation of the gut immune system by probiotics are not yet completely understood. The present work studies the effect of a fermented milk containing probiotic bacteriumLactobacillus(Lb.)caseiDN114001 on different parameters of the gut immune system involved with the nonspecific, innate and adaptive response. BALB/c mice received the probiotic bacteriumLb. caseiDN114001 or the probiotic fermented milk (PFM). The interaction of the probiotic bacteria with the intestine was studied by electron and fluorescence microscopy. The immunological parameters were studied in the intestinal tissue and in the supernatant of intestinal cells (IC). Results showed that the probiotic bacterium interact with the IC. The whole bacterium or its fragments make contact with the gut associated immune cells. The PFM stimulated the IC with IL-6 release, as well as cells related to the nonspecific barrier and with the immune cells associated with the gut. This last activity was observed through the increase in the population of different immune cells: T lymphocytes and IgA+ B lymphocytes, and by the expression of cell markers related to both innate and adaptive response (macrophages). PFM was also able to activate the enzyme calcineurine responsible for the activation of the transcriptional factor NFAT. PFM induced mucosal immune stimulation reinforcing the non-specific barrier and modulating the innate immune response in the gut, maintaining the intestinal homeostasis.

Lactic acid bacteria (LAB) represent a heterogeneous group of microorganisms that are naturally present in many foods. Some selected strains are frequently added as probiotics in order to confer specific benefits to consumers. Many studies have shown that LAB possess therapeutic properties since they are able to prevent the development of some diseases, as shown mostly on animal models for cancer, infections and gastrointestinal disorders such as intestinal inflammation. They have been shown to regulate mucosal immune responses by modulating the production and liberation of regulatory agents such as cytokines by the host. Some of these cytokines, such as the anti-inflammatory interleukin-10 (IL-10), modulate the inflammatory immune response, thus immunomodulation is a mechanism by which LAB can prevent certain inflammatory bowel diseases (IBD). Since oxidative stress participates to the inflammatory processes and to the appearance of damages in pathologies of the gastrointestinal tract of humans such as IBD, LAB could also prevent inflammation by eliminating reactive oxygen species (ROS) through the activity of antioxidant enzymes. Engineering LAB to produce either antioxidant enzymes (such as catalases and superoxide dismutases) or anti-inflammatory cytokines (such as IL-10) is a strategy currently exploited by several groups. These novel strains have successfully been used to prevent inflammatory bowel diseases in animal models and could be evaluated in human clinical trials. Here, we present an overview of the current knowledge of the mechanisms by which LAB can be used to prevent undesired intestinal inflammatory responses. Fil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Perdigon, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: Miyoshi, Anderson. Universidade Federal de Minas Gerais; Brasil Fil: Rochat, Tatiana. Institut National de la Recherche Agronomique; Francia Fil: Bermudez Humaran, Luis. Institut National de la Recherche Agronomique; Francia Fil: Langella, Philippe. Institut National de la Recherche Agronomique; Francia Fil: Sesma, Fernando Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Azevedo, Vasco. Universidade Federal de Minas Gerais; Brasil

BackgroundMicrobial colonization of the intestine after birth is an important step for the development of the gut immune system. The acquisition of passive immunity through breast-feeding may influence the pattern of bacterial colonization in the newborn. The aim of this work was to evaluate the effect of the administration of a probiotic fermented milk (PFM) containing yogurt starter cultures and the probiotic bacteria strainLactobacillus caseiDN-114001 to mothers during nursing or their offspring, on the intestinal bacterial population and on parameters of the gut immune system.ResultsFifteen mice of each group were sacrificed at ages 12, 21, 28 and 45 days. Large intestines were taken for determination of intestinal microbiota, and small intestines for the study of secretory-IgA (S-IgA) in fluid and the study of IgA+ cells, macrophages, dendritic cells and goblet cells on tissue samples. The consumption of the PFM either by the mother during nursing or by the offspring after weaning modified the development of bifidobacteria population in the large intestine of the mice. These modifications were accompanied with a decrease of enterobacteria population. The administration of this PFM to the mothers improved their own immune system and this also affected their offspring. Offspring from mice that received PFM increased S-IgA in intestinal fluids, which mainly originated from their mother's immune system. A decrease in the number of macrophages, dendritic cells and IgA+ cells during the suckling period in offspring fed with PFM was observed; this could be related with the improvement of the immunity of the mothers, which passively protect their babies. At day 45, the mice reach maturity of their own immune system and the effects of the PFM was the stimulation of their mucosal immunity.ConclusionThe present work shows the beneficial effect of the administration of a PFM not only to the mothers during the suckling period but also to their offspring after weaning and until adulthood. This effect positively improved the intestinal microbiota that are related with a modulation of the gut immune response, which was demonstrated with the stimulation of the IgA + cells, macrophages and dendritic cells.

The effect of the long-term administration of commercial fermented milk containing probiotic bacteria in the mucosal immune response and peritoneal macrophages was analyzed. BALB/c mice were fed with fermented milk for 98 consecutive days. Small and large intestines were removed for histology; IgA, CD4, CD8 cells and cytokines-producing cells were counted. The influence on the immune cells associated with bronchus and mammary glands as well as on peritoneal macrophages was also analyzed. Continuous oral administration of fermented milk increased IgA+ cells in both parts of the intestine (small and large intestine). IL-10, a regulatory cytokine, increased in the intestinal cells in most samples. TNFα, IFNγ and IL-2 producing cells were also enhanced. Values for CD4 and CD8+ cell populations in lamina propria of the intestine were increased in relation to the control throughout the assay. No modifications in the histology of intestines were observed. Long-term consumption of fermented milk enhanced intestinal mucosa immunity, mediated by IgA+ cells and by cytokine production. This improvement of gut immunity was maintained and down-regulated by cytokines such as IL-10, preventing gut inflammatory immune response. The effect of this fermented milk on mucosal sites distant to the gut, such as bronchus and mammary glands, showed that in both tissues the increase in IgA+ cells was only observed at the beginning of the continuous consumption and no modifications in the number of cytokine positive cells were found. Similar observations were found when phagocytic activity of peritoneal macrophages was measured. It was demonstrated that the most evident effect of long-term consumption of fermented milk was observed in the intestine. Immunodulatory effects and the maintenance of intestinal homeostasis without secondary effects after long-term administration of fermented milk were also observed. Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: Chaves, Analia Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Carmuega, Esteban. Nutritia; Argentina Fil: Weill, Ricardo. DANONE Argentina S.A. Departamento de Investigación y desarrollo; Argentina Fil: Antóine, J.. DANONE VITAPOLE. Research Centre; Francia Fil: Perdigon, Gabriela del Valle. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina

Reactive oxygen species, such as hydrogen peroxide (H2O 2), are involved in various aspects of tumour development. Decreasing their levels can therefore be a promising approach for colon cancer prevention. The objective of this study was to evaluate the effect of catalase-producing Lactococcus lactis on the prevention of an experimental murine 1,2-dimethylhydrazine (DMH)-induced colon cancer. DMH-treated BALB/c mice received either a catalase-producing L. lactis strain or the isogenic non-catalase-producing strain as a control, whereas other untreated mice did not receive bacterial supplementation. Catalase activity and H2O 2 levels in intestinal fluids and blood samples were measured, and changes in the histology of the large intestines during tumour progression were evaluated. The catalase-producing L. lactis strain used in this study was able to slightly increase catalase activities in DMH-treated mice (1.19 ± 0.08 U ml-1) and reduce H2O2 levels (3.4 ± 1.1 μM) compared to (i) animals that received the non-catalase-producing strain (1.00 ± 0.09 U ml-1, 9.0 ± 0.8 μM), and (ii) those that did not receive bacterial supplementation (1.06 ± 0.07 U ml-1, 10.0 ± 1.1 μM). Using the histopathological grading scale of chemically induced colorectal cancer, animals that received the catalase-producing L. lactis had a significantly lesser extent of colonic damage and inflammation (2.0 ± 0.4) compared to animals that received the non-catalase-producing L. lactis (4.0 ± 0.3) or those that did not receive bacterial supplementation (4.7 ± 0.5). The catalase-producing L. lactis strain used in this study was able to prevent tumour appearance in an experimental DMH-induced colon cancer model. Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Perdigon, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: Miyoshi, Anderson. Universidade Federal de Minas Gerais; Brasil Fil: Langella, Philippe. Institut National de la Recherche Agronomique; Francia Fil: Azevedo, Vaso. Universidade Federal de Minas Gerais; Brasil Fil: Sesma, Fernando Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina

The mammalian microbiota comprises several hundred different bacterial species, many of which have a beneficial effect on the host. For example, they are involved in preventing colonization of the gut by pathogens and maintaining the gut mucosal immunity (85). The gut microbiota is more abundant in the large intestine of mammals, with densities rising to over 1011 organisms/g intestinal content (84, 86). The number of bacterial cells in the entire gut exceeds the number of eukaryotic cells in the host, but under normal circumstance they coexist without any adverse effect on the host. The influence of the resident microflora on mucosal immune function and gut health has become an area of scientific and clinical importance (22, 26). There is an active dialogue between the commensal microorganisms and the host mucosal immune system (21, 48). This cross talk elicits different host responses to commensal and pathogenic bacteria. Commensal bacteria may even share molecular patterns recognized by toll-like receptors (TLRs), which can recognize patterns associated mainly with pathogens. However, the mucosal immune system of the healthy intestine allows the persistence of this microbiota associated with the intestine and avoids immunological tolerance, maintaining the intestinal homeostasis. Now, there is acceptance of the concept that oral tolerance is not generated by commensal intestinal bacteria; the host would ignore or fail to recognize the presence of indigenous microorganisms (49). The healthy host is able to elicit a good mucosal immune response against luminal antigens and to maintain a “physiological state of inflammation” in the gut, but it is also capable of responding to invading commensal organisms or pathogens. In the healthy host the penetration of the commensal bacteria is usually prevented by the barrier afforded by the intestinal epithelium and the immune cells associated with the mucosa, which are highly adapted to the presence of the normal microbiota (71). The signals sent by these microorganisms prevent their penetration and keep them outside the intestinal tissue. If the commensal microorganisms invade the host tissues, the innate immune mechanisms contribute to their rapid clearance, but when pathogens enter the intestine, innate and adaptive mechanisms are coordinately stimulated to respond to the danger signals (38, 60). Although mucosal epithelial tissues form an efficient barrier that prevents the entrance of the environmental pathogens and the external antigens into the host internal milieu, mucosal tissues represent the main sites of infection by pathogens. Many attempts have been made to understand the gut immunomodulation by pathogenic bacteria but not the mechanisms involved in the modulation of the gut immune system by commensal bacteria and by nonpathogenic microorganisms present in many foods included in the daily diet. Fil: Maldonado Galdeano, María Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: de Moreno, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: Vinderola, Celso Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Bibas Bonet, María Eugenia. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: Perdigon, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina

Previous studies have shown that compounds released during milk fermentation by Lactobacillus helveticus are implicated in the antitumour effect of this product. Here the effects of the consumption, during 2 or 7 days, of kefir or kefir cell-free fraction (KF) on the systemic and local immune responses in mammary glands and tumours using a murine hormone-dependent breast cancer model were studied. In the tumour control group, mice did not receive these products. At the end of the feeding period, mice were injected subcutaneously with tumour cells in the mammary gland. Four days post-injection, they received kefir or KF on a cyclical basis. Rate of tumour development, cytokines in serum; mammary gland tissue, and tumour isolated cells were monitored. Two-day cyclical administration of both products delayed tumour growth. Both kefir and KF increased IL-10 in serum and decreased IL-6(+) cells (cytokine involved in oestrogen synthesis) in mammary glands. Two-day cyclical administration of KF increased IL-10(+) cells in mammary glands and in tumours and decreased IL-6(+) cells in tumour. This study demonstrated the modulatory capacity of KF on the immune response in mammary glands and tumours and the importance of the administration period to obtain this effect. Fil: de Moreno, Maria Alejandra. Université de Moncton. Départment de Chimie-Biochimie; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: Matar, Chantal. Université de Moncton. Départment de Chimie-Biochimie; Canadá Fil: Farnworth, E.. Agriculture and Agri-Food; Canadá Fil: Perdigon, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina