Quinoa sourdough-based biscuits with high antioxidant activity fermented with autochthonous lactic acid bacteria.

AIMS: To evaluate the capacity of autochthonous lactic acid bacteria (LAB) (43) from Andean grains to increase the antioxidant activity (AOA) and total phenolic compounds (TPCs) in quinoa sourdough to select best performing strains to be used as starter cultures in the elaboration of biscuits. METHODS AND RESULTS: Microbial growth (CFU per g) and pH were evaluated during quinoa dough fermentation. Counts were increased in a range of 0.61-2.97 log CFU per g and pH values between 3.95 and 4.54 were determined after 24 h at 30°C of fermentation. Methanolic (ME) and aqueous (AE) extracts were obtained at the end of fermentation, and free radical scavenging capacity was performed by the DPPH and ABTS methods. ME was selected for further analysis using other methods and TPC quantification. Principal component analysis showed the highest scores of growth, acidification capacity, AOA and TPC for the strains Lc. mesenteroides subsp. mesenteroides CRL 2131 and L. plantarum CRL 1964 and CRL 1973. AOA and TPC in biscuits made with sourdough from these LAB were higher than the acidified and uninoculated controls. CONCLUSIONS: Autochthonous LAB strains (3) increased the AOA of quinoa-based biscuits. SIGNIFICANCE AND IMPACT OF THE STUDY: Quinoa sourdough obtained with selected LAB is suitable as an ingredient for bakery foods with improved antioxidant status.

Effect of processing on polyphenol profile, aflatoxin concentration and allergenicity of peanuts.

Worldwide peanuts are often thermally processed before consumption, which might alter its bioactive composition and toxicity. The presented work explores the effect of processing methods such as roasting, frying, and pressure cooking on the bioactive composition, polyphenol profiles, aflatoxin concentration and, allergenicity response of peanuts. Effect of processing methods was assessed by monitoring total polyphenol content (TPC), total flavonoid content (TFC), antioxidant activity by DPPH & ABTS radicals, sensory analysis and, indirect ELISA. Compared to raw peanuts, all processing methods caused significant differences in TPC, TFC, DPPH & ABTS radical scavenging activities. Comparison of polyphenol profiles of raw to processed peanuts by LC-ESI-Q-TOF-MS chromatograms revealed different effects on concentrations of individual bioactive polyphenols. Indirect ELISA showed a significant decrease in the assay response on pressure cooking as compared to other samples. Total aflatoxin concentration was significantly reduced after processing in roasted (97.7%) and fried (98.3%) peanuts. Optimum processing conditions based on bioactive concentration and sensory analysis were found to be, roasting: 150 °C for 10 min, frying: 170 °C for 2 min and, pressure cooking: 15 min. Polyphenol profiles and bioactive constituents of peanuts were influenced by processing and may alter health benefits associated with them hence, vital for research and food industry applications.

Neuroprotective effects associated with immune modulation by selected lactic acid bacteria in a Parkinson's disease model.

OBJECTIVES: Parkinson's disease (PD) is a neurodegenerative process that affects the motor function and involves an inflammatory response and B vitamin deficiencies. The aim of this study was to evaluate the effect of B-group vitamin-producing and immunomodulatory lactic acid bacteria (LAB) in a murine model of PD. METHODS: The effect of Lactobacillus plantarum CRL 2130 (a riboflavin producer), Streptococcus thermophilus CRL 807 (an immunomodulatory strain), and Streptococcus thermophilus CRL 808 (a folate producer) were evaluated individually and as a mixture in mice injected with 1-methyl-4-fenil-1,2,3,6-tetrahidropiridina. Motor capacity, tyrosine hydrolase in the brain, and cytokine concentrations in serum and brain tissues were evaluated in 1-methyl-4-fenil-1,2,3,6-tetrahidropiridina-treated mice after bacterial supplementation. RESULTS: The mice receiving the selected LAB showed significantly improved motor skills compared with those that did not receive bacterial supplementation. When given the mixture of all 3 strains together, the animals had higher brain tyrosine hydrolase-positive cell counts, decreased inflammatory cytokines interleukin 6 and tumor necrosis factor alpha in serum, and increased antiinflammatory cytokine interleukin 10 in serum and brain tissues compared with animals that did not receive LAB supplementation. CONCLUSIONS: The results showed the potential of a selected LAB mixture to improve motor behavior and neuroinflammation in PD. This probiotic mixture could be used as an adjunct treatment in the control of PD.

Retraction Note to: Lactobacillus casei BL23 regulates Treg and Th17 T-cell populations and reduces DMH-associated colorectal cancer.

This article has been retracted. Please see the retraction notice for more detail: https://doi.org/10.1007/s00535-015-1158-9 .

Impact of extracellular folic acid levels on oviductal gene expression.

Folate plays a specific role as methyl donor for nucleotide synthesis and genomic methylation patterns, which in turn are important epigenetic determinants in gene expression. Previous studies have revealed the presence of folate in bovine oviductal fluid as well as the existence of a fine-tuned regulation of the gene expression of folate receptors and transporters in bovine oviduct epithelial cells (BOECs). However, the functional implications of folate in the oviduct remain unknown. The present study aimed to assess the effect of folic acid (FA) on expression levels of selected genes that potentially respond to the folate status in in vitro BOECs. To obtain an insight into the optimization of a culture system for assays, gene expression of folate receptors and transporters was compared between BOECs grown in monolayers and in suspension. The results showed that BOECs from isthmus and ampulla in suspension culture better preserved the region-dependent gene expression profile than in monolayers. Subsequently, BOECs from both anatomical regions were separately cultured in suspension for 24 h assaying different FA concentrations: I) TCM-199 (control); II) TCM-199 + 1 µM FA (similar to the oviduct concentration); III) TCM-199 + 10 µM FA and IV) TCM-199 + 100 µM FA. Expression analysis of genes related to important cellular processes including folate transport, DNA methylation, cell-cell interaction, antioxidant activity and signaling pathways was performed in BOECs using RT-qPCR. Our data demonstrated that addition of 1 µM FA did not affect mRNA levels of most genes analyzed. In contrast, BOECs cultured with 10 µM FA exhibited increased mRNA expression levels of genes involved in folate intake, DNA methylation and antioxidant protection. It is worth noting that at 100 µM FA, transcriptional response in BOECs mainly resulted in decreased mRNA levels of the majority of the genes assayed. Interestingly, cytotoxicity analysis showed a similar LDH activity in the culture media of the experimental groups, indicating that cell integrity was not affected by the FA concentrations assayed. In conclusion, our findings suggest that folate can affect BOECs, promoting changes in gene activity in a framework of functional readjustments in response to environmental conditions.

Application of vitamin-producing lactic acid bacteria to treat intestinal inflammatory diseases.

Recent studies have shown that inflammatory diseases are becoming more frequent throughout the world. The causes of these disorders are multifactorial and include genetic, immunological, and environmental factors, and intestinal microbiota dysbiosis. The use of beneficial microorganisms has shown to be useful in the prevention and treatment of disorders such as colitis, mucositis, and even colon cancer by their immune-stimulating properties. It has also been shown that certain vitamins, especially riboflavin and folate derivatives, have proven to be helpful in the treatment of these diseases. The application of vitamin-producing lactic acid bacteria, especially strains that produce folate and riboflavin together with immune-stimulating strains, could be used as adjunct treatments in patients suffering from a wide range of inflammatory diseases since they could improve treatment efficiency and prevent undesirable side effects in addition to their nutrition values. In this review, the most up to date information on the current knowledge and uses of vitamin-producing lactic acid bacteria is discussed in order to stimulate further studies in this field.

Beneficial effect of a mixture of vitamin-producing and immune-modulating lactic acid bacteria as adjuvant for therapy in a recurrent mouse colitis model.

Inflammatory bowel diseases are chronic and relapsing-remitting disorders that affect the gastrointestinal tract. Previously, the administration of folate and riboflavin-producing lactic acid bacteria (LAB) or an immune-modulating strain showed beneficial effects as they were able to reduce the acute inflammation in mouse models. The aim of this work was to evaluate a mixture of vitamin-producing and immune-modulating LAB administering together with an anti-inflammatory drug during the remission period of a mouse model of recurrent colitis. BALB/c mice were intrarectally instilled with trinitrobenzene sulfonic acid (TNBS) and those who recovered from this acute challenge were given the LAB mixture, mesalazine, or the combination of both (mesalazine + LAB) during 21 days, followed by a second challenge with TNBS. Control mice instilled with ethanol (vehicle of TNBS) and receiving the different treatments were also evaluated in order to study the effect of chronic anti-inflammatory therapy. The combination of mesalazine and LAB mixture was the most effective to decrease the intestinal damage at macroscopic and histological levels and to reduce pro-inflammatory cytokines (IL-6 and TNF-α) in intestinal fluids. In animals instilled with ethanol, mesalazine produced a loss of body weight and intestinal damages with increased IL-6. These side effects were prevented by the co-administration of mesalazine and the LAB mixture. The LAB blend did not affect the primary anti-inflammatory treatment, was able to improve it, and also prevented the side effects of this therapy.

Protective effect of the riboflavin-overproducing strain Lactobacillus plantarum CRL2130 on intestinal mucositis in mice.

OBJECTIVES: Intestinal mucositis (IM) is a local inflammatory response that causes alterations of the intestinal structure that in turn affect nutrient absorption and a side effect that is commonly associated with cancer treatments. Lactobacillus plantarum CRL2130 is a riboflavin-overproducing strain that has previously been shown to provide antiinflammatory properties. The objective of this study was to evaluate the effects of this riboflavin-producing strain in a chemically induced murine mucositis model. METHODS: Mucositis was induced by daily injections of 5-fluororacil (5-FU) after which mice were either given L. plantarum CRL2130, CRL725 (strain from which CRL2130 was derived that does not overproduce riboflavin), or commercial riboflavin twice daily during 6 d of chemotherapy agent injections. The effect of the strains and riboflavin was also evaluated in vitro using Caco-2 intestinal cancer cell cultures to determine if they interfere with 5-FU's anticancer activity. RESULTS: The administration of L. plantarum CRL2130 significantly attenuated the pathologic changes induced by 5-FU in mice such as body weight loss, diarrhea, shortening of villus height, increases in proinflammatory cytokine concentrations, and elevated production of interleukin 10. In vitro assays using Caco-2 cells showed that the effectiveness of 5-FU was not affected by L. plantarum CRL2130 and that this strain exerted an inhibitory mechanism against oxidative stress. CONCLUSIONS: These results indicate that the riboflavin-overproducing strain L. plantarum CRL2130 could be useful to prevent mucositis during cancer treatments and would not affect the primary treatment.

Vitamin Producing Lactic Acid Bacteria as Complementary Treatments for Intestinal Inflammation.

BACKGROUND: Current therapies for against inflammatory bowel disease (IBD) are sometimes limited by high costs, high toxicities and/or undesirable side effects, reasons for which new treatments are constantly being developed and studied. In this regards, an increasing mass of data has demonstrated that fecal transplantations and probiotic supplementations have shown promising effects and could be considered as adjunct IBD treatments to decrease some of the unwanted side effects caused by primary treatments. Furthermore, there is also mounting evidence that suggests that certain vitamins could provide antiinflammatory effects and it has been shown that certain strains of lactic acid bacteria (LAB), the most commonly used probiotic microorganisms, can produce biologically active forms of certain vitamins. OBJECTIVE: To discuss the potential role of the vitamin-producing LAB on intestinal inflammatory diseases. METHOD: A thorough search of bibliographic databases for peer-reviewed research on the effect of vitamins produced by LAB on inflammatory processes was performed. RESULTS: There is mounting research that vitamin producing LAB could provide antiinflammatory effects. CONCLUSION: The potential role of vitamin producing LAB was discussed not only because they could be used to decrease inflammation but also because they could provide the host with essential nutrients that are normally deficient in IBD patients due to altered intestinal morphologies.

Beneficial effects on host energy metabolism of short-chain fatty acids and vitamins produced by commensal and probiotic bacteria.

The aim of this review is to summarize the effect in host energy metabolism of the production of B group vitamins and short chain fatty acids (SCFA) by commensal, food-grade and probiotic bacteria, which are also actors of the mammalian nutrition. The mechanisms of how these microbial end products, produced by these bacterial strains, act on energy metabolism will be discussed. We will show that these vitamins and SCFA producing bacteria could be used as tools to recover energy intakes by either optimizing ATP production from foods or by the fermentation of certain fibers in the gastrointestinal tract (GIT). Original data are also presented in this work where SCFA (acetate, butyrate and propionate) and B group vitamins (riboflavin, folate and thiamine) production was determined for selected probiotic bacteria.

Anti-cancer effect of lactic acid bacteria expressing antioxidant enzymes or IL-10 in a colorectal cancer mouse model.

The association between inflammatory bowel diseases and colorectal cancer is well documented. The genetic modification of lactic acid bacteria as a tool to increase the anti-inflammatory potential of these microorganisms has also been demonstrated. Thus the aim of the present work was to evaluate the anti-cancer potential of different genetically modified lactic acid bacteria (GM-LAB) producing antioxidant enzymes (catalase or superoxide dismutase) or the anti-inflammatory cytokine IL-10 (protein or DNA delivery) using a chemical induced colon cancer murine model. Dimethilhydrazine was used to induce colorectal cancer in mice. The animals received GM-LAB producing anti-oxidant enzymes, IL-10 or a mixture of different GM-LAB. Intestinal damage, enzyme activities and cytokines were evaluated and compared to the results obtained from mice that received the wild type strains from which derived the GM-LAB. All the GM-LAB assayed showed beneficial effects against colon cancer even though they exerted different mechanisms of action. The importance to select LAB with innate beneficial properties as the progenitor strain was demonstrated with the GM-LAB producing anti-oxidant enzymes. In addition, the best effects for the mixtures GM-LAB that combine different anti-inflammatory mechanism. Results indicate that mixtures of selected LAB and GM-LAB could be used as an adjunct treatment to decrease the inflammatory harmful environment associated to colorectal cancer, especially for patients with chronic intestinal inflammation who have an increased risk to develop colorectal cancer.

Lactobacillus casei BL23 regulates Treg and Th17 T-cell populations and reduces DMH-associated colorectal cancer.

BACKGROUND: Chronic intestinal inflammation alters host physiology and could lead to colorectal cancer (CRC). We have previously reported beneficial effects of the probiotic strain of Lactobacillus casei BL23 in different murine models of intestinal inflammation. In addition, there is an emerging interest on the potential beneficial effects of probiotics to treat CRC. We thus explored whether L. casei BL23 displays protective effects on CRC. METHODS: Mice were subcutaneously injected with 1,2-dimethylhydrazine (DMH) weekly during 10 weeks and orally administered with L. casei BL23 in the drinking water until the 10th week. Multiple plaque lesions in the large intestine were observed macroscopically and counted and intestinal tissues were also histologically analyzed. Finally, T-cell populations and cytokine production were evaluated after co-incubation of L. casei BL23 with spleen cells from non-treated mice to determine the immuno-modulatory effects of this bacterium. RESULTS: Our results show that oral treatment with this probiotic bacterium modulates host immune responses and significantly protect mice against DMH-induced CRC. This protection may be associated with the modulation of regulatory T-cells towards a Th17-biased immune response accompanied by the expression of regulatory cytokines (IL-6, IL-17, IL-10 and TGF-ß), as demonstrated in L. casei BL23-treated splenocytes, but also with the colonic expression of IL-22 observed in vivo on L. casei BL23-treated mice; suggesting the induction of a fine-tune Th17-biased response. CONCLUSIONS: Altogether our results reveal the high potential of L. casei BL23 to treat CRC and opens new frontiers for the study of immunomodulatory functions of probiotics.

Recombinant invasive Lactococcus lactis can transfer DNA vaccines either directly to dendritic cells or across an epithelial cell monolayer.

Lactococcus lactis (L. lactis), a generally regarded as safe (GRAS) bacterium has recently been investigated as a mucosal delivery vehicle for DNA vaccines. Because of its GRAS status, L. lactis represents an attractive alternative to attenuated pathogens. Previous studies showed that eukaryotic expression plasmids could be delivered into intestinal epithelial cells (IECs) by L. lactis, or recombinant invasive strains of L. lactis, leading to heterologous protein expression. Although expression of antigens in IECs might lead to vaccine responses, it would be of interest to know whether uptake of L. lactis DNA vaccines by dendritic cells (DCs) could lead to antigen expression as they are unique in their ability to induce antigen-specific T cell responses. To test this, we incubated mouse bone marrow-derived DCs (BMDCs) with invasive L. lactis strains expressing either Staphylococcus aureus Fibronectin Binding Protein A (LL-FnBPA+), or Listeria monocytogenes mutated Internalin A (LL-mInlA+), both strains carrying a plasmid DNA vaccine (pValac) encoding for the cow milk allergen ß-lactoglobulin (BLG). We demonstrated that they can transfect BMDCs, inducing the secretion of the pro-inflammatory cytokine IL-12. We also measured the capacity of strains to invade a polarized monolayer of IECs, mimicking the situation encountered in the gastrointestinal tract. Gentamycin survival assay in these cells showed that LL-mInlA+ is 100 times more invasive than L. lactis. The cross-talk between differentiated IECs, BMDCs and bacteria was also evaluated using an in vitro transwell co-culture model. Co-incubation of strains in this model showed that DCs incubated with LL-mInlA+ containing pValac:BLG could express significant levels of BLG. These results suggest that DCs could sample bacteria containing the DNA vaccine across the epithelial barrier and express the antigen.

Relationships between the genome and some phenotypical properties of Lactobacillus fermentum CECT 5716, a probiotic strain isolated from human milk.

Lactobacillus fermentum CECT 5716, isolated from human milk, has immunomodulatory, anti-inflammatory, and anti-infectious properties, as revealed by several in vitro and in vivo assays, which suggests a strong potential as a probiotic strain. In this work, some phenotypic properties of L. fermentum CECT 5716 were evaluated, and the genetic basis for the obtained results was searched for in the strain genome. L. fermentum CECT 5716 does not contain plasmids and showed neither bacteriocin nor biogenic amine biosynthesis ability but was able to produce organic acids, glutathione, riboflavin, and folates and to moderately stimulate the maturation of mouse dendritic cells. No prophages could be induced, and the strain was sensitive to all antibiotics proposed by European Food Safety Authority (EFSA) standards, while no transmissible genes potentially involved in antibiotic resistance were detected in its genome. Globally, there was an agreement between the phenotype properties of L. fermentum CECT 5716 and the genetic information contained in its genome.

Effect of probiotic administration on the intestinal microbiota, current knowledge and potential applications.

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.

Correlation between fibronectin binding protein A expression level at the surface of recombinant lactococcus lactis and plasmid transfer in vitro and in vivo.

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.

Evaluation of the probiotic potential and effect of encapsulation on survival for Lactobacillus plantarum ST16Pa isolated from papaya.

Capability to produce antilisterial bacteriocins by lactic acid bacteria (LAB) can be explored by the food industry as a tool to increase the safety of foods. Furthermore, probiotic activity of bacteriogenic LAB brings extra advantages to these strains, as they can confer health benefits to the consumer. Beneficial effects depend on the ability of the probiotic strains to maintain viability in the food during shelf-life and to survive the natural defenses of the host and multiply in the gastrointestinal tract (GIT). This study evaluated the probiotic potential of a bacteriocinogenic Lactobacillus plantarum strain (Lb. plantarum ST16Pa) isolated from papaya fruit and studied the effect of encapsulation in alginate on survival in conditions simulating the human GIT. Good growth of Lb. plantarum ST16Pa was recorded in MRS broth with initial pH values between 5.0 and 9.0 and good capability to survive in pH 4.0, 11.0 and 13.0. Lb. plantarum ST16Pa grew well in the presence of oxbile at concentrations ranging from 0.2 to 3.0%. The level of auto-aggregation was 37%, and various degrees of co-aggregation were observed with different strains of Lb. plantarum, Enterococcus spp., Lb. sakei and Listeria, which are important features for probiotic activity. Growth was affected negatively by several medicaments used for human therapy, mainly anti-inflammatory drugs and antibiotics. Adhesion to Caco-2 cells was within the range reported for other probiotic strains, and PCR analysis indicated that the strain harbored the adhesion genes mapA, mub and EF-Tu. Encapsulation in 2, 3 and 4% alginate protected the cells from exposure to 1 or 2% oxbile added to MRS broth. Studies in a model simulating the transit through the GIT indicated that encapsulated cells were protected from the acidic conditions in the stomach but were less resistant when in conditions simulating the duodenum, jejunum, ileum and first section of the colon. To our knowledge, this is the first report on a bacteriocinogenic LAB isolated from papaya that presents application in food biopreservation and may be beneficial to the consumer health due to its potential probiotic characteristics.

Use of superoxide dismutase and catalase producing lactic acid bacteria in TNBS induced Crohn's disease in mice.

Reactive oxygen species are involved in various aspects of intestinal inflammation and tumor development. Decreasing their levels using antioxidant enzymes, such as catalase (CAT) or superoxide dismutase (SOD) could therefore be useful in the prevention of certain diseases. Lactic acid bacteria (LAB) are ideal candidates to deliver these enzymes in the gut. In this study, the anti-inflammatory effects of CAT or SOD producing LAB were evaluated using a trinitrobenzenesulfonic acid (TNBS) induced Crohn's disease murine model. Engineered Lactobacillus casei BL23 strains producing either CAT or SOD, or the native strain were given to mice before and after intrarectal administration of TNBS. Animal survival, live weight, intestinal morphology and histology, enzymatic activities, microbial translocation to the liver and cytokines released in the intestinal fluid were evaluated. The mice that received CAT or SOD-producing LAB showed a faster recovery of initial weight loss, increased enzymatic activities in the gut and lesser extent of intestinal inflammation compared to animals that received the wild-type strain or those that did not receive bacterial supplementation. Our findings suggest that genetically engineered LAB that produce antioxidant enzymes could be used to prevent or decrease the severity of certain intestinal pathologies.

Evaluation of the anti-inflammatory effect of milk fermented by a strain of IL-10-producing Lactococcus lactis using a murine model of Crohn's disease.

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.

Oral administration of a catalase-producing Lactococcus lactis can prevent a chemically induced colon cancer in mice.

Reactive oxygen species, such as hydrogen peroxide (H2O2), 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 H2O2 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 microM) compared to (i) animals that received the non-catalase-producing strain (1.00+/-0.09 U ml(-1), 9.0+/-0.8 microM), and (ii) those that did not receive bacterial supplementation (1.06+/-0.07 U ml(-1), 10.0+/-1.1 microM). 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.