Estimation of the potential antitumor activity of microencapsulated Lactobacillus acidophilus yogurt formulation in the attenuation of tumorigenesis in Apc(Min/+) mice

Current Landscape and Potential Challenges of Immune Checkpoint Inhibitors in Microsatellite Stable Metastatic Colorectal Carcinoma

Colorectal cancer (CRC) is the third most frequent cancer and the second most common cause of cancer-related death in Europe. High microsatellite instability (MSI-H) due to a deficient DNA mismatch repair (dMMR) system can be found in 5% of metastatic CRC (mCRC) and has been established as a biomarker of response to immunotherapy in these tumors. Therefore, immune checkpoint inhibitors (ICIs) in mCRC with these characteristics were evaluated with results showing remarkable response rates and durations of response. The majority of mCRC cases have high levels of DNA mismatch repair proteins (pMMR) with consequent microsatellite stability or low instability (MSS or MSI-low), associated with an inherent resistance to ICIs. This review aims to provide a comprehensive analysis of the possible approaches to overcome the mechanisms of resistance and evaluates potential biomarkers to establish the role of ICIs in pMMR/MSS/MSI-L (MSS) mCRC.

Role of a mixed probiotic product, VSL#3, in the prevention and treatment of colorectal cancer

Colorectal cancer (CRC) is a multifactorial disease. The incidence of this type of cancer in younger patients has increased in recent years, and more strategies are needed to prevent and delay the progression of CRC. Probiotics play an adjunctive role in the prevention and treatment of CRC and can not only prevent the onset and delay the progression of disease but also reduce the side effects after the application of anti-cancer drugs. The anti-cancer effect of individual probiotics has been extensively studied, and the exact curative effect of various probiotics has been found, but the anti-cancer effect of mixed probiotics is still not well summarized. In this review, we discuss the positive effects of mixed probiotics on CRC and the related mechanisms of action, especially VSL#3 (VSL Pharmaceuticals, Inc., Gaithersburg, MD, USA), thus providing new ideas for the treatment of CRC. Moreover, we suggest the need to search for more therapeutic possibilities, especially via the research and application of synbiotics and postbiotics.

Novel targets in rectal cancer by considering lncRNA-miRNA-mRNA network in response to Lactobacillus acidophilus consumption: a randomized clinical trial

We aimed to explore the lncRNA-miR-mRNA network in response to Lactobacillus acidophilus (L. acidophilus) consumption in rectal cancer patients. The candidate miRs were first taken from the GEO and TCGA databases. We constructed the lncRNA-miR-mRNA network using the high-throughput sequencing data. At last, we created a heatmap based on the experimental data to show the possible correlation of the selected targets. The expression levels of selected targets were measured in the samples of 107 rectal cancer patients undergoing placebo and probiotic consumption and 10 noncancerous subjects using Real-Time PCR. Our analysis revealed a group of differentially expressed 12 miRs and 11 lncRNAs, and 12 genes in rectal cancer patients. A significant expression increase of the selected tumor suppressor miRs, lncRNAs, and genes and a substantial expression decrease of the selected oncomiRs, onco-lncRNAs, and oncogenes were obtained after the probiotic consumption compared to the placebo group. There is a strong correlation between some network components, including miR-133b and IGF1 gene, miR-548ac and MSH2 gene, and miR-21 and SMAD4 gene. In rectal cancer patients, L. acidophilus consumption was associated with improved expression of the lncRNA-miR-mRNA network, which may provide novel monitoring and therapeutic approaches.

Irritable bowel syndrome

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Diagnosis and Treatment of Irritable Bowel Syndrome: Clinical Recommendations of the Russian Gastroenterological Association and Association of Coloproctologists of Russia

Aim. Current clinical recommendations accentuate current methods for the diagnosis and treatment of irritable bowel syndrome (IBS).

Key points.IBS is a functional bowel disorder manifested with recurrent, at least weekly, abdominal pain with the following attributes (any two leastwise): link to defecation, its frequency or stool shape. The symptoms are expected to persist for at minimum three months in a total six-month follow-up. Similar to other functional gastrointestinal (GI) disorders, IBS can be diagnosed basing on the patient symptoms compliance with Rome IV criteria, provided the absence of potentially symptom-causative organic GI diseases. Due to challenging differential diagnosis, IBS can be appropriately established per exclusionem, with pre-examination as follows: general and biochemical blood tests; tissue transglutaminase IgA/IgG antibody tests; thyroid hormones test; faecal occult blood test; hydrogen glucose/ lactulose breath test for bacterial overgrowth; stool test for enteric bacterial pathogens and Clostridium difficile A/B toxins; stool calprotectin test; abdominal ultrasound; OGDS, with biopsy as appropriate; colonoscopy with biopsy. The IBS sequence is typically wavelike, with alternating remissions and exacerbations often triggered by psychoemotional stress. Treatment of IBS patients includes dietary and lifestyle adjustments, various-class drug agents prescription and psychotherapeutic measures.

Conclusion. Adherence to clinical recommendations can facilitate timely diagnosis and improve medical aid quality in patients with different clinical IBS variants.

An Update on the Effects of Probiotics on Gastrointestinal Cancers

Because of their increasing prevalence, gastrointestinal (GI) cancers are regarded as an important global health challenge. Microorganisms residing in the human GI tract, termed gut microbiota, encompass a large number of living organisms. The role of the gut in the regulation of the gut-mediated immune responses, metabolism, absorption of micro- and macro-nutrients and essential vitamins, and short-chain fatty acid production, and resistance to pathogens has been extensively investigated. In the past few decades, it has been shown that microbiota imbalance is associated with the susceptibility to various chronic disorders, such as obesity, irritable bowel syndrome, inflammatory bowel disease, asthma, rheumatoid arthritis, psychiatric disorders, and various types of cancer. Emerging evidence has shown that oral administration of various strains of probiotics can protect against cancer development. Furthermore, clinical investigations suggest that probiotic administration in cancer patients decreases the incidence of postoperative inflammation. The present review addresses the efficacy and underlying mechanisms of action of probiotics against GI cancers. The safety of the most commercial probiotic strains has been confirmed, and therefore these strains can be used as adjuvant or neo-adjuvant treatments for cancer prevention and improving the efficacy of therapeutic strategies. Nevertheless, well-designed clinical studies are still needed for a better understanding of the properties and mechanisms of action of probiotic strains in mitigating GI cancer development.

Microencapsulated Bifidobacterium bifidum and Lactobacillus gasseri in Combination with Quercetin Inhibit Colorectal Cancer Development in ApcMin/+ Mice

Recent studies have suggested that flavonoids such as quercetin and probiotics such as Bifidobacterium bifidum (Bf) and Lactobacillus gasseri (Lg) could play a relevant role in inhibiting colon cancer cell growth. Our study investigated the role of dietary supplementation with microencapsulated probiotics (Bf and Lg) along with quercetin in the development of mouse colorectal cancer (CRC). Methods: Adenomatous polyposis coli/multiple intestinal neoplasia (ApcMin/+) mice were fed a standard diet or the same diet supplemented with microencapsulated probiotics (Bf and Lg strains, 107 CFU/100 g food) or both probiotics strains plus microencapsulated quercetin (15 mg/100 g food) for 73 days. Changes in body and organ weights, energy metabolism, intestinal microbiota, and colon tissue were determined. The expression of genes related to the Wnt pathway was also analyzed in colon samples. Results: Dietary supplementation with microencapsulated probiotics or microencapsulated probiotics plus quercetin reduced body weight loss and intestinal bleeding in ApcMin/+ mice. An improvement in energy expenditure was observed after 8 weeks but not after 10 weeks of treatment. A supplemented diet with microencapsulated Bf and Lg reduced the number of aberrant crypt foci (ACF) and adenomas by 45% and 60%, respectively, whereas the supplementation with Bf, Lg and quercetin decreased the number of ACF and adenomas by 57% and 80%, respectively. Microencapsulated Bf and Lg in combination with quercetin could exert inhibition of the canonical Wnt/β-catenin signaling pathway in the colon of ApcMin/+ mice Conclusions: The administration of microencapsulated Bf and Lg, individually or in combination with quercetin, inhibits the CRC development in ApcMin/+ mice.

Smectite promotes probiotic biofilm formation in the gut for cancer immunotherapy

Administration of probiotics to regulate the immune system is a potential anti-tumor strategy. However, oral administration of probiotics is ineffective because of the poor inhabitation of exogenous bacteria in host intestines. Here we report that smectite, a type of mineral clay and established anti-diarrhea drug, promotes expansion of probiotics (especially Lactobacillus) in the murine gut and subsequently elicits anti-tumor immune responses. The ion-exchangeable microstructure of smectite preferentially promotes lactic acid bacteria (LABs) to form biofilms on smectite in vitro and in vivo. In mouse models, smectite laden with LAB biofilms (Lactobacillus and Bifidobacterium) inhibits tumor growth (when used alone) and enhances the efficacy of chemotherapy or immunotherapy (when used in combination with either of them) by activating dendritic cells (DCs) via Toll-like receptor 2 (TLR2) signaling. Our findings suggest oral administration of smectite as a promising strategy to enrich probiotics in vivo for cancer immunotherapy.

Study of the Influence of Sociodemographic and Lifestyle Factors on Consumption of Dairy Products: Preliminary Study in Portugal and Brazil

Sociodemographic characteristics, including regional variations, have been associated with different food consumption patterns. Behavioral factors and lifestyle variables may also contribute to different food dietary trends. In this way, the present study intended to investigate the consumption habits of the most relevant types of dairy products around the world and relate them to sociodemographic factors, for example, age, sex, education and country as well as with some anthropometric and behavioral aspects, for example, body mass index, satisfaction with body weight and exercise or sedentary lifestyles. One other objective of the study was to categorize the lifestyles of the participants, according to measured variables linked with hours of inactivity or exercise, in order to use these as possible differentiating variables for the consumption of dairy products. The study involved a questionnaire survey undertaken on a non-probabilistic convenience sample of participants from Portugal (PT) and Brazil (BR), and participation was voluntary and anonymous. The data analysis involved different statistical techniques: basic statistics, chi-square tests, factor analysis, cluster analysis and tree classification analysis. The results showed that semi skimmed milk is never consumed by about half of the participants (47.4% for PT and 46.7 for BR), and those numbers increase for skimmed (64.8% for PT and 50.9% for BR), chocolate flavored milk (82.6% for PT and 65.6% for BR) and enriched milks (94.8% for PT and 85.3% for BR). Cheeses are also consumed in the two countries by small numbers of people. The number of participants consuming imported cheeses in both countries was particularly low (only 4.0% consume these more than once a week in both countries), suggesting national products may be preferred. It was further observed that those who consume cheese do it seldom (once a week) or sometimes (2–3 times per week). Butter is also consumed by only about half of the adult population (43.8% for PT and 49.5% for BR), but the percentage of those who never consume butter increases for skimmed butter (66.0% for PT and 82.6% for BR) and unsalted butter (70.2% for PT and 69.1% for BR). The consumption of yogurts also follows similar low consumption patterns. The most frequently consumed yogurt types in Portugal are liquid (30.5% consume regularly) and natural yogurts (34.8% consume regularly), while in Brazil the most frequent are creamy fruit pulp yogurt (14.4% consume regularly), liquid (13.7% consume regularly) and Greek type yogurt (10.2% consume regularly). A factor analysis and a cluster analysis established groups according to lifestyles, as follows: 1—Screeners, 2—Exercisers, 3—Travelers and 4—Others. These lifestyles were found to be influential in the consumption of dairy products for all classes of dairy tested: milk, cheese, yogurt and butter. For example, the screeners were found to consume more milk, more butter, more cheese and more yogurt. Additionally, other influential factors were age, sex, education, BMI and satisfaction with body weight. Nevertheless, country was not a meaningfully discriminant variable in relation to the other variables included in the classification analysis. The results concluded that, despite some small differences in the patterns of consumption of dairy products in both countries, the levels of consumption of dairy products are extremely low, for all classes studied (milk, cheese, yogurt or butter). Additionally, it was concluded that some factors are influential on the level of consumption of dairy products, and therefore decision makers can plan their interventions according to the characteristics of the targeted segments of the population, according to lifestyle, age, sex, education, BMI and satisfaction with body weight.

Preclinical Evidence of Probiotics in Colorectal Carcinogenesis: A Systematic Review

BACKGROUND

Colorectal cancer, the second major cause of cancer deaths, imposes a major health burden worldwide. There is growing evidence that supports that the use of probiotics is effective against various diseases, especially in gastrointestinal diseases, including the colorectal cancer, but the differences between the strains, dose, and frequency used are not yet clear.

AIMS

To perform a systematic review to compile the results of studies carried out in animal models and investigated the effect of probiotics on colorectal carcinogenesis.

METHODS

Studies were selected in PubMed/MEDLINE and Scopus according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Search filters were developed using three parameters: probiotics, colorectal cancer, and animal model.

RESULTS

From a structured search, we discovered 34 original articles and submitted them to a risk of bias analysis using SYRCLE's tool. The studies show a great diversity of models, most were conducted in rats (55.8%) and used 1,2 dimethylhydrazine as the drug to induce colorectal carcinogenesis (61.7%). The vast majority of trials investigated Lactobacillus (64%) and Bifidobacterium (29.4%) strains. Twenty-six (86.6%) studies found significant reduction in lesions or tumors in the animals that received probiotics. The main methodological limitation was the insufficient amount of information for the adequate reproducibility of the trials, which indicated a high risk of bias due to incomplete characterization of the experimental design.

CONCLUSIONS

The different probiotics' strains showed anti-carcinogenic effect, reduced the development of lesions and intestinal tumors, antioxidant and immunomodulatory activity, and reduced fecal bacterial enzymes.

A critical review of antibiotic resistance in probiotic bacteria

Probiotics are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit upon the host. At present, probiotics are gaining popularity worldwide and are widely used in food and medicine. Consumption of probiotics is increasing with further in-depth research on the relationship between intestinal flora and host health. Most people pay more attention to the function of probiotics but ignore their potential risks, such as infection and antibiotic resistance transfer to pathogenic microbes. Physiological functions, effects and mechanisms of action of probiotics were covered in this review, as well as the antibiotic resistance phenotypes, mechanisms and genes found in probiotics. Typical cases of antibiotic resistance of probiotics were also highlighted, as well as the potential risks (including pathogenicity, infectivity and excessive immune response) and corresponding strategies (dosage, formulation, and administration route). This timely study provides an avenue for further research, development and application of probiotics.

Polymeric carriers for enhanced delivery of probiotics

Probiotics are live microorganisms (usually bacteria), which are defined by their ability to confer health benefits to the host, if administered adequately. Probiotics are not only used as health supplements but have also been applied in various attempts to prevent and treat gastrointestinal (GI) and non-gastrointestinal diseases such as diarrhea, colon cancer, obesity, diabetes, and inflammation. One of the challenges in the use of probiotics is putative loss of viability by the time of administration. It can be due to procedures that the probiotic products go through during fabrication, storage, or administration. Biocompatible and biodegradable polymers with specific moieties or pH/enzyme sensitivity have shown great potential as carriers of the bacteria for 1) better viability, 2) longer storage times, 3) preservation from the aggressive environment in the stomach and 4) topographically targeted delivery of probiotics. In this review, we focus on polymeric carriers and the procedures applied for encapsulation of the probiotics into them. At the end, some novel methods for specific probiotic delivery, possibilities to improve the targeted delivery of probiotics and some challenges are discussed.

Oral supplementation with lactobacilli to prevent colorectal cancer in preclinical models

Colorectal cancer (CRC) is still a major threat for public health, as it is the third most common cancer in men and the second in women and it ranks second among tumors in terms of mortality. Evidence from the last decades emphasizes the complex role of gut microbial composition in CRC development. Historically, it is believed that dairy products, a source of lactobacilli and other lactic acid bacteria, are beneficial for human health and help in preventing CRC. We searched online literature for trials evaluating the preventive role of lactobacilli in CRC animal models. Most of selected studied assessed a relevant role of lactobacilli in preventing CRC and precursor lesions. Mechanisms through which this effect was achieved are supposed to regard immunomodulation, regulation of apoptosis, gut microbial modulation, genes expression, reduction of oxidative stress and others. Lactobacilli oral supplementation is reported to be effective in preventing CRC in animal models, even if the underlying mechanisms of action are still not fully understood.

Consumption of modern and traditional Moroccan dairy products and colorectal cancer risk: a large case control study

PURPOSE

The main objective of this study is to describe the association between the consumption of either traditional or modern dairy products or calcium intakes and the risk of colorectal cancer (CRC) in the adult Moroccan population.

METHODS

A case-control study was conducted in five Moroccan hospital centers. The study was matched on sex, age (± 5 years) and center. Data were collected using validated food frequency questionnaire (FFQ) taking into account different types of Moroccan dairy products. Conditional logistic regression models were used to assess the association between dairy products consumption, calcium intakes and CRC risk subtypes. In all statistical tests, the significance level was set at 0.05.

RESULTS

Among 1453 cases and 1453 matched controls, 50.7% were women and 49.3% were men. Milk OR^b 0.84, 95% CI 0.74-0.96 and yogurt OR^b 0.74, 95% CI 0.64-0.86 were inversely associated with CRC risk. Similar inverse associations were observed for traditional dairy products namely Lben OR^b 0.77, 95% CI 0.67-0.88, Raib OR^b 0.86, 95% CI 0.76-0.96 and Jben OR^b 0.77, 95% CI 0.67-0.88. The dairy calcium intake was inversely associated to CRC overall OR^b 0.83, 95% CI 0.74-0.93.

CONCLUSIONS

Our study supports previous international evidence and suggests that individuals who have a high intake of either modern or traditional dairy products are at lower risk for CRC. These findings should be further confirmed by longitudinal data and studies investigating potential pathways involved.

Randomised clinical trial: Bifidobacterium lactis NCC2818 probiotic vs placebo, and impact on gut transit time, symptoms, and gut microbiology in chronic constipation

BACKGROUND

Constipation is a prevalent gastrointestinal disorder. Patient dissatisfaction with prescribed medications is common, and there is need for alternative management strategies. Evidence shows that Bifidobacterium species may be beneficial in constipation.

AIM

To investigate changes in physiological and clinical measures of gut function in patients with chronic constipation following the consumption of Bifidobacterium lactis NCC2818, compared to placebo.

METHODS

Participants were randomised to a 4-week supplementation with B. lactis NCC2818 (1.5 x 10¹⁰ CFU/d) or placebo. Gut transit time was measured using a radio-opaque marker, while symptoms and quality of life were assessed using validated questionnaires. Gut microbiota composition was assessed using quantitative polymerase chain reaction. Analysis of covariance was used for normally distributed variables, and Mann-Whitney test for non-normally distributed variables.

RESULTS

Seventy-five participants were randomised. There was no significant difference between the probiotic and placebo groups in gut transit time change from baseline to week 2 (-11.7 hours, SD 33.0 hours vs -12.9 hours, SD 33.6 hours; P = 0.863) or to week 4 (-20.4 hours, SD 32.5 h vs -8.7 hours, SD 33.8 hours; P = 0.103). There were also no improvements in stool output, symptoms, or quality of life. No differences were found in Bifidobacterium concentrations between the probiotic and placebo groups at week 4 (9.5 log₁₀ /g dry faeces, SD 0.3 vs 9.4 log₁₀ /g, SD 1.0; P = 0.509).

CONCLUSIONS

Bifidobacterium lactis NCC2818 was not effective in the management of mild chronic constipation. This study highlights the importance of further studies and their publication to better understand the strain-specific effects of probiotics.

Lactobacillus rhamnosus Enhances the Immunological Antitumor Effect of 5-Fluorouracil against Colon Cancer

BACKGROUND AND OBJECTIVES

5-Fluorouracil (5-FU) is the most common anticancer therapeutic, even though its response rate as a single agent is usually less than 20%. Lactobacillus rhamnosus bacteria reduce the severity of gastrointestinal tract infections, with additional functions in cancer prevention. This study investigated the histological and immunological changes associated with the combination treatment of L. rhamnosus and 5-FU in mice with colon cancer.

MATERIAL AND METHODS

Five groups of male mice were classified as follows; Group A: Mice injected with azoxymethane (AOM) to induce colon cancer, Group AL: Mice injected with AOM and orally administered L. rhamnosus alone, Group AF: Mice injected with AOM and administered 5-FU, Group AFL: Mice injected with AOM and treated with both L. rhamnosus and 5-FU and Group C: Untreated control mice.

RESULTS

A reduction in inflammatory features with a normal histological structure was observed in the colon of the AFL group compared to those in the other treated groups. The intestinal mucosa of the AFL group showed a significant downregulation in K-ras and Treg/IL-10 transcription levels. This downregulation was associated with an improvement in the innate and adaptive immune responses through increased TLR2 and Th1/IFNγ transcription. TNFα and IL-6 protein expression was significantly elevated in the serum of the AFL groups compared to levels in both the A and AF groups.

CONCLUSION

This study provides evidence about the potential immunological influence of L. rhamnosus when used in combination with 5-FU as a novel colon cancer therapeutic strategy.

In vitro and in vivo evidences for innate immune stimulators lactic acid bacterial starters isolated from fermented camel dairy products

Probiotics are commensals with special characteristics that are essential for the development of the immune system, and may protect mucosal surfaces against pathogens. In this study, a total of 40 lactic acid bacteria (LAB) were isolated from different raw and fermented camel's milk samples collected from Saudi Arabia (Makkah area) and Egypt (Fayoum), and tested for the probiotic properties. Among them, Pro 4 and Pro 7 isolates exhibited excellent probiotic potential including bile salt (0.2-0.6%), phenol tolerance (0.2-0.4%) and salt tolerance (0.0-10%). Furthermore, both strains exhibited antimicrobial activity against wide range of food-borne pathogens and Dermatophytes with average zone inhibition of 37.5, 35.5, 34.5, 27.5, 25 and 23.5 mm for Staphylococcus aureus, Trichophyton mentagrophytes, Escherichia coli, Listeria monocytogens, Candida albicans and Salmonella typhi, respectively. Furthermore, the in vivo study indicated that these strains significantly improved the mucosal immune responses through an increase in expression of TLR2 and IFNγ mRNA in mice intestine as well as increased the synthesis of polyclonal IgG, IgM and IgA in mice blood sera. Accordingly, due to these unique probiotic properties, both selected strains could be potentially used as probiotic starter cultures for fermented dairy foods as well as functional food and health products.

Intestinal microbiota: a novel perspective in colorectal cancer biotherapeutics

It is believed that genetic factors, immune system dysfunction, chronic inflammation, and intestinal microbiota (IM) dysbiosis contribute to the pathogenesis of colorectal cancer (CRC). The beneficial role played by the direct regulation of IM in inflammatory bowel disease treatment is identified by the decreased growth of harmful bacteria and the increased production of anti-inflammatory factors. Interestingly, gut microbiota has been proven to inhibit tumor formation and progression in inflammation/carcinogen-induced CRC mouse models. Recently, evidence has indicated that IM is involved in the negative regulation of tumor immune response in tumor microenvironment, which then abolishes or accelerates anticancer immunotherapy in several tumor animals. In clinical trials, a benefit of IM-based CRC therapies in improving the intestinal immunity balance, epithelial barrier function, and quality of life has been reported. Meanwhile, specific microbiota signature can modulate host's sensitivity to chemo-/radiotherapy and the prognosis of CRC patients. In this review, we aim to 1) summarize the potential methods of IM-based therapeutics according to the recent results; 2) explore its roles and underlying mechanisms in combination with other therapies, especially in biotherapeutics; 3) discuss its safety, deficiency, and future perspectives.

Microbiota modification by probiotic supplementation reduces colitis associated colon cancer in mice

AIM

To investigate the effect of probiotic supplementation during the development of an experimental model of colitis associated colon cancer (CAC).

METHODS

C57BL/6 mice received an intraperitoneal injection of azoxymethane (10 mg/kg), followed by three cycles of sodium dextran sulphate diluted in water (5% w/v). Probiotic group received daily a mixture of Lactobacillus acidophilus, Lactobacillus rhamnosus and Bifidobacterium bifidum. Microbiota composition was assessed by 16S rRNA Illumina HiSeq sequencing. Colon samples were collected for histological analysis. Tumor cytokines was assessed by Real Time-PCR (Polymerase Chain Reaction); and serum cytokines by Multiplex assay. All tests were two-sided. The level of significance was set at P < 0.05. Graphs were generated and statistical analysis performed using the software GraphPad Prism 5.0. The project was approved by the institutional review board committee.

RESULTS

At day 60 after azoxymethane injection, the mean number of tumours in the probiotic group was 40% lower than that in the control group, and the probiotic group exhibited tumours of smaller size (< 2 mm) (P < 0.05). There was no difference in richness and diversity between groups. However, there was a significant difference in beta diversity in the multidimensional scaling analysis. The abundance of the genera Lactobacillus, Bifidobacterium, Allobaculum, Clostridium XI and Clostridium XVIII increased in the probiotic group (P < 0.05). The microbial change was accompanied by reduced colitis, demonstrated by a 46% reduction in the colon inflammatory index; reduced expression of the serum chemokines RANTES and Eotaxin; decreased p-IKK and TNF-α and increased IL-10 expression in the colon.

CONCLUSION

Our results suggest a potential chemopreventive effect of probiotic on CAC. Probiotic supplementation changes microbiota structure and regulates the inflammatory response, reducing colitis and preventing CAC.

Vitamin D/VDR, Probiotics, and Gastrointestinal Diseases

Vitamin D is an important factor in regulating inflammation, immune responses, and carcinoma inhibition via action of its receptor, vitamin D receptor (VDR). Recent studies have demonstrated the role of vitamin D/VDR in regulating host-bacterial interactions. Probiotics are beneficial bacteria with the power of supporting or favoring life on the host. In the current review, we will discuss the recent progress on the roles of vitamin D/VDR in gut microbiome and inflammation. We will summarize evidence of probiotics in modulating vitamin D/VDR and balancing gut microbiota in health and gastrointestinal diseases. Moreover, we will review the clinical application of probiotics in prevention and therapy of IBD or colon cancer. Despite of the gains, there remain several barriers to advocate broad use of probiotics in clinical therapy. We will also discuss the limits and future direction in scientific understanding of probiotics, vitamin D/VDR, and host responses.

Anticancer effects of the microbiome and its products

The human gut microbiome modulates many host processes, including metabolism, inflammation, and immune and cellular responses. It is becoming increasingly apparent that the microbiome can also influence the development of cancer. In preclinical models, the host response to cancer treatment has been improved by modulating the gut microbiome; this is known to have an altered composition in many diseases, including cancer. In addition, cancer treatment with microbial agents or their products has the potential to shrink tumours. However, the microbiome could also negatively influence cancer prognosis through the production of potentially oncogenic toxins and metabolites by bacteria. Thus, future antineoplastic treatments could combine the modulation of the microbiome and its products with immunotherapeutics and more conventional approaches that directly target malignant cells.

Metabiotics: One Step ahead of Probiotics; an Insight into Mechanisms Involved in Anticancerous Effect in Colorectal Cancer

Colorectal cancer is closely associated with environment, diet and lifestyle. Normally it is treated with surgery, radiotherapy or chemotherapy but increasing systemic toxicity, resistance and recurrence is prompting scientists to devise new potent and safer alternate prophylactic or therapeutic strategies. Among these, probiotics, prebiotics, synbiotics, and metabiotics are being considered as the promising candidates. Metabiotics or probiotic derived factors can optimize various physiological functions of the host and offer an additional advantage to be utilized even in immunosuppressed individuals. Interestingly, anti colon cancer potential of probiotic strains has been attributable to metabiotics that have epigenetic, antimutagenic, immunomodulatory, apoptotic, and antimetastatic effects. Thus, it's time to move one step further to utilize metabiotics more smartly by avoiding the risks associated with probiotics even in certain normal/or immuno compromised host. Here, an attempt is made to provide insight into the adverse effects associated with probiotics and beneficial aspects of metabiotics with main emphasis on the modulatory mechanisms involved in colon cancer.

Design and validation of an orally administrated active L. fermentum-L. acidophilus probiotic formulation using colorectal cancer Apc Min/+ mouse model

Probiotics have been shown to have beneficial properties in attenuating the risk of colorectal cancer (CRC) development. However, functional evidence to support such effects for some probiotic bacteria are relatively unknown. Here, we document a significant antioxidant, anti-proliferative and pro-apoptotic activities of Lactobacillus acidophilus ATCC 314 and Lactobacillus fermentum NCIMB 5221 on CRC cells, particularly when used in combination (La-Lf). Furthermore, a superior synergistic activity on the inhibition of tumor growth and modulation of cell proliferation and epithelial markers in the Apc ^Min/+ CRC mouse model was explored, based on the expression levels of Ki-67, E-cadherin, β-catenin, and cleaved caspase-3 (CC3) proteins. The anti-cancer activity of La-Lf co-culture was significantly enhanced in vitro with significant reduced proliferation (38.8 ± 6.9 %, P = 0.009) and increased apoptosis (413 RUL, P < 0.001) towards cancer cells, as well as significant protection of normal colon cell growth from toxic treatment (18.6 ± 9.8 %, P = 0.001). La-Lf formulation (10¹⁰cfu/animal/day) altered aspects of intestinal tumorigenesis by significantly reducing intestinal tumor multiplicity (1.7-fold, P = 0.016) and downregulating cellular proliferation markers, including β-catenin (P = 0.041) and Ki-67 (P = 0.008). In conclusion, La-Lf showed greater protection against intestinal tumorigenesis supporting a potential use as a biotherapeutic for the prevention of CRC.

Production Conditions Affect the In Vitro Anti-Tumoral Effects of a High Concentration Multi-Strain Probiotic Preparation

A careful selection of the probiotic agent, standardization of the dose and detailed characterization of the beneficial effects are essential when considering use of a probiotic for the dietary management of serious diseases. However, changes in the manufacturing processes, equipment or facilities can result in differences in the product itself due to the live nature of probiotics. The need to reconfirm safety and/or efficacy for any probiotic product made at a different factory is therefore mandatory. Recently, under the brand VSL#3®, a formulation produced by a manufacturer different from the previous one, has been commercialized in some European countries (the UK and Holland). VSL#3 is a high concentration multi-strain preparation which has been recognized by the main Gastroenterology Associations for the dietary management of pouchitis as well as ulcerative colitis. We have compared the “original” VSL#3 produced in USA with the “newfound” VSL#3 produced in Italy. According to our results, the “newfound” VSL#3 has 130–150% more “dead bacteria” compared to the “original” product, raising concerns for the well-known association between dead microbes with adverse effects. The abilities of bacterial lysates from the two formulations to influence in vitro viability and proliferation of different tumor cell lines also resulted different. The repair of previously scratched monolayers of various adherent tumor cell lines (i.e. HT1080, and Caco-2 cells) was inhibited more significantly by the “original” VSL#3 when compared to the “newfound” VSL#3. Tumor cell cycle profile, in particular cell cycle arrest and apoptotic death of the cancer cells, further confirms that the “original” VSL#3 has a better functional profile than the “newfound” VSL#3, at least in in vitro. Our data stress the importance of the production conditions for the “newfound” VSL#3 considering that this product is intended to be used for the dietary management of patients with very serious diseases, such as chronic inflammatory bowel diseases.

The Potential Role of Probiotics in Cancer Prevention and Treatment

The human gut microbiota has a significant effect on many aspects of human physiology such as metabolism, nutrient absorption, and immune function. Imbalance of the microbiota has been implicated in many disorders including inflammatory bowel disease, obesity, asthma, psychiatric illnesses, and cancers. As a kind of functional foods, probiotics have been shown to play a protective role against cancer development in animal models. Clinical application of probiotics indicated that some probiotic strains could diminish the incidence of postoperative inflammation in cancer patients. Chemotherapy or radiotherapy-related diarrhea was relieved in patients who were administered oral probiotics. The present review summarizes the up-to-date studies on probiotic effects and the underlying mechanisms related to cancer. At present, it is commonly accepted that most commercial probiotic products are generally safe and can improve the health of the host. By modulating intestinal microbiota and immune response, some strains of probiotics can be used as an adjuvant for cancer prevention or/and treatment.

Associations of Probiotics with Vitamin D and Leptin Receptors and their Effects on Colon Cancer

Colorectal cancer (CRC) is one of most common causes of cancer-related death worldwide. Recent studies have suggested that microbial and environmental factors including diet and lifestyle can impact on colon cancer development. Vitamin D deficiency and dysfunction of vitamin D receptor (VDR) also correlate with colon cancer. Moreover, leptin, a 16-kDa polypeptide, participates in the regulation of food intake and is associated with other environmental factors affecting colon cancer through the leptin receptor. Altered levels of serum leptin and patterns of expression of its receptor (LPR) may be observed in human colon tumours. Furthermore, the collected data from in vitro and in vivo studies have indicated that consuming probiotic non-pathogenic lactic acid bacteria have beneficial effects on colon cancer. Probiotics, inflammation and vitamin D/VDR have been correlated with leptin and its receptor and are also with colon cancer. Thus, in this paper, we review recent progress on the roles of probiotic, vitamin D/VDR and leptin/LPR in inflammation and colon cancer.

Consumption of Bifidobacterium animalis subsp. lactis BB-12 in yogurt reduced expression of TLR-2 on peripheral blood-derived monocytes and pro-inflammatory cytokine secretion in young adults

PURPOSE

Probiotic bacteria modulate immune parameters and inflammatory outcomes. Emerging evidence demonstrates that the matrix used to deliver probiotics may influence the efficacy of probiotic interventions in vivo. The aims of the current study were to evaluate (1) the effect of one species, Bifidobacterium animalis subsp. lactis BB-12 at a dose of log10 ± 0.5 CFUs/day on immune responses in a randomized, partially blinded, 4-period crossover, free-living study, and (2) whether the immune response to BB-12 differed depending on the delivery matrix.

METHODS

Healthy adults (n = 30) aged 18-40 years were recruited and received four treatments in a random order: (A) yogurt smoothie alone; smoothie with BB-12 added (B) before or (C) after yogurt fermentation, or (D) BB-12 given in capsule form. At baseline and after each 4-week treatment, peripheral blood mononuclear cells (PBMCs) were isolated, and functional and phenotypic marker expression was assessed.

RESULTS

BB-12 interacted with peripheral myeloid cells via Toll-like receptor 2 (TLR-2). The percentage of CD14⁺HLA-DR⁺ cells in peripheral blood was increased in male participants by all yogurt-containing treatments compared to baseline (p = 0.0356). Participants who consumed yogurt smoothie with BB-12 added post-fermentation had significantly lower expression of TLR-2 on CD14⁺HLA-DR⁺ cells (p = 0.0186) and reduction in TNF-α secretion from BB-12- (p = 0.0490) or LPS-stimulated (p = 0.0387) PBMCs compared to baseline.

CONCLUSIONS

These findings not only demonstrate a potential anti-inflammatory effect of BB-12 in healthy adults, but also indicate that the delivery matrix influences the immunomodulatory properties of BB-12.

Extraction of Peptidoglycan from L. paracasei subp. Paracasei X12 and Its Preliminary Mechanisms of Inducing Immunogenic Cell Death in HT-29 Cells

L. paracasei subp. paracaseiX12 was previously isolated from a Chinese traditional fermented cheese with anticancer activities and probiotic potential. Herein, the integral peptidoglycan (X12-PG) was extracted by a modified trichloroacetic acid (TCA) method. X12-PG contained the four representative amino acids Asp, Glu, Ala and Lys, and displayed the similar lysozyme sensitivity, UV-visible scanning spectrum and molecular weight as the peptidoglycan standard. X12-PG could induce the production of apoptotic bodies observed by transmission electron microscopy (TEM). X12-PG could significantly induced the translocation of calreticulin (CRT) and the release of high mobility group box 1 protein (HMGB1), the two notable hallmarks of immunogenic cell death (ICD), with the endoplastic reticulum (ER) damaged and subsequently intracellular [Ca²⁺] elevated. Our findings implied that X12-PG could induce the ICD of HT-29 cells through targeting at the ER. The present results may enlighten the prospect of probiotics in the prevention of colon cancer.

Yacon (Smallanthus sonchifolius) and Lactobacillus acidophilus CRL 1014 reduce the early phases of colon carcinogenesis in male Wistar rats

The modifying effects of aqueous yacon extract (AYE) and Lactobacillus acidophilus CRL 1014 against colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) in male Wistar rats were investigated. Animals were allocated into five groups: G1: untreated group; G2: DMH-treated group; G3: DMH+L. acidophilus-treated group; G4: DMH+AYE-treated group; G5: DMH+L. acidophilus and AYE-treated group. A significant reduction (p<0.05) in leukocyte DNA damage and in colonic cell proliferation was observed after the first DMH administration in G3 (probiotic), G4 (prebiotic) and G5 (synbiotic) groups. In this moment, a significant increase (p<0.05) in colonic apoptosis was also observed in G3 (probiotic) and G5 (synbiotic) groups. In special, at five months after DMH administrations, a significant reduction (p<0.05) in ACF development was observed in G3 (probiotic), G4 (prebiotic) and G5 (synbiotic) groups. Incidence of colon tumors was lower at five months in G4 (prebiotic) and G5 (synbiotic) groups but not in eight months after DMH administrations. In conclusion, the findings suggest that the oral treatments have potential effects as a chemopreventive agent against colon carcinogenesis on an early stage of tumor development.

Lactobacillus salivarius Ren prevent the early colorectal carcinogenesis in 1, 2-dimethylhydrazine-induced rat model

AIMS

The objective of this study was to investigate the impact of Lactobacillus salivarius Ren (LS) on modulating colonic micro flora structure and influencing host colonic health in a rat model with colorectal precancerous lesions.

METHODS AND RESULTS

Male F344 rats were injected with 1, 2-dimethylhydrazine (DMH) and treated with LS of two doses (5 × 10(8) and 1 × 10(10) CFU kg(-1) body weight) for 15 weeks. The colonic microflora profiles, luminal metabolites, epithelial proliferation and precancerous lesions [aberrant crypt foci (ACF)] were determined. A distinct segregation of colonic microflora structures was observed in LS-treated group. The abundance of one Prevotella-related strain was increased, and the abundance of one Bacillus-related strain was decreased by LS treatment. These changes were accompanied by increased short-chain fatty acid levels and decreased azoreductase activity. LS treatment also reduced the number of ACF by c. 40% and suppressed epithelial proliferation.

CONCLUSIONS

Lactobacillus salivarius Ren improved the colonic microflora structures and the luminal metabolisms in addition preventing the early colorectal carcinogenesis in DMH-induced rat model.

SIGNIFICANCE AND IMPACT OF THE STUDY

Colonic microflora is an important factor in colorectal carcinogenesis. Modulating the structural shifts of microflora may provide a novel option for preventing colorectal carcinogenesis. This study suggested a potential probiotic-based approach to modulate the intestinal microflora in the prevention of colorectal carcinogenesis.

Gastrointestinal cancers: influence of gut microbiota, probiotics and prebiotics

Cancers of the gastrointestinal (GI) tract continue to represent a major health problem, despite progress in therapy. Gut microbiota is a key element related to the genesis of GI cancers, countless papers addressing this burning issue across the world. We provide an updated knowledge of the involvement of gut microbiota in GI tumorigenesis, including its underlying mechanisms. We present also a comprehensive review of the evidence from animal and clinical studies using probiotics and/or prebiotics in the prevention and/or therapy of GI tumours, of GI cancer therapy-related toxicity and of post-operative complications. We summarize the anticarcinogenic mechanisms of these biotherapeutics from in vitro, animal and clinical interventions. More research is required to reveal the interactions of microflora with genetic, epigenetic and immunologic factors, diet and age, before any firm conclusion be drawn. Well-designed, randomized, double blind, placebo-controlled human studies using probiotics and/or prebiotics, with adequate follow-up are necessary in order to formulate directions for prevention and therapy.

Activation of Gpr109a, receptor for niacin and the commensal metabolite butyrate, suppresses colonic inflammation and carcinogenesis

Commensal gut microflora and dietary fiber protect against colonic inflammation and colon cancer through unknown targets. Butyrate, a bacterial product from fermentation of dietary fiber in the colon, has been implicated in this process. GPR109A (encoded by Niacr1) is a receptor for butyrate in the colon. GPR109A is also a receptor for niacin, which is also produced by gut microbiota and suppresses intestinal inflammation. Here we showed that Gpr109a signaling promoted anti-inflammatory properties in colonic macrophages and dendritic cells and enabled them to induce differentiation of Treg cells and IL-10-producing T cells. Moreover, Gpr109a was essential for butyrate-mediated induction of IL-18 in colonic epithelium. Consequently, Niacr1(-/-) mice were susceptible to development of colonic inflammation and colon cancer. Niacin, a pharmacological Gpr109a agonist, suppressed colitis and colon cancer in a Gpr109a-dependent manner. Thus, Gpr10a has an essential role in mediating the beneficial effects of gut microbiota and dietary fiber in colon.

Enrichment of Bifidobacterium longum subsp. infantis ATCC 15697 within the human gut microbiota using alginate-poly-L-lysine-alginate microencapsulation oral delivery system: an in vitro analysis using a computer-controlled dynamic human gastrointestinal model

This study evaluates alginate-poly-L-lysine-alginate Bifidobacterium longum subsp. infantis ATCC 15697-loaded microcapsules to enrich the human gut microbiota. The cell survival of alginate-poly-L-lysine-alginate microencapsulated B. infantis ATCC 15697 in gastric acid, bile, and through human gastrointestinal transit was investigated, as well as the formulation's effect on the gut microbiota. Results show that microencapsulation increases B. infantis ATCC 15697 cell survival at pH1.0 (33.54 ± 2.80% versus <1.00 ± 0.00%), pH1.5 (41.15 ± 2.06% versus <1.00 ± 0.00%), pH2.0 (60.88 ± 1.73% versus 36.01 ± 2.63%), pH3.0 (75.43 ± 1.23% versus 46.30 ± 1.43%), pH4.0 (71.40 ± 2.02% versus 47.75 ± 3.12%) and pH5.0 (73.88 ± 3.79% versus 58.93 ± 2.26%) (p < 0.05). In addition, microencapsulation increases cell survival at 0.5% (76.85 ± 0.80% versus 70.77 ± 0.64%), 1.0% (59.99 ± 0.97% versus 53.47 ± 0.58%) and 2.0% (53.10 ± 1.87% versus 44.59 ± 1.52%) (p < 0.05) (w/v) bile. Finally, daily administration of alginate-poly-L-lysine-alginate microencapsulated B. infantis ATCC 15697 in a human gastrointestinal model induces a significant enrichment of B. infantis within the ascending (184.51 ± 17.30% versus 53.83 ± 17.82%; p < 0.05), transverse (174.79 ± 25.32% versus 73.17 ± 15.30%; p < 0.05) and descending (94.90 ± 25.22% versus 46.37 ± 18.93%; p > 0.05) colonic microbiota.

Novel probiotic dissolvable carboxymethyl cellulose films as oral health biotherapeutics: in vitro preparation and characterization

OBJECTIVES

Oral health is influenced by the mouth's resident microorganisms. Dental caries and periodontitis are oral disorders caused by imbalances in the oral microbiota. Probiotics have potential for the prevention and treatment of oral disorders. Current formulations, including supplements and foods, have limitations for oral delivery including short storage time, low residence time in the mouth, effects on food consistency, and low patient compliance. Oral thin films (OTFs) may be efficient in delivering probiotics to the mouth. This research aims to develop a novel carboxymethyl cellulose (CMC)-probiotic-OTF to deliver probiotics for the treatment/prevention of oral disorders.

METHODS

CMC-OTFs were developed with varying CMC concentration (1.25 - 10 mg/mL), weight (5 - 40 g), thickness (16 - 262 μm), hygroscopicity (30.8 - 78.9 mg/cm(2) film), and dissolving time (135 - 600 s). The 10 g 5 mg/mL CMC-OTF was selected and used to incorporate Lactobacillus fermentum NCIMB 5221 (6.75 × 10(8) cells/film), a probiotic with anti-inflammatory potential for periodontitis treatment and capable of inhibiting microorganisms responsible for dental caries and oral candidiasis.

RESULTS

The CMC-OTF maintained probiotic viability and antioxidant activity following 150 days of storage with a production of 549.52 ± 26.08 μM Trolox equivalents.

CONCLUSION

This research shows the successful development and characterization of a novel probiotic-CMC-OTF with potential as an oral health biotherapeutic.

Probiotics in colorectal cancer (CRC) with emphasis on mechanisms of action and current perspectives

Colorectal cancer (CRC) is the third most common form of cancer. Diverse therapies such as chemotherapy, immunotherapy and radiation have shown beneficial effects, but are limited because of their safety and toxicity. Probiotic formulations have shown great promise in CRC as preventive and early stage therapeutics. This review highlights the importance of a balanced intestinal microbiota and summarizes the recent developments in probiotics for treating CRC. Specifically, this report describes evidence of the role of probiotics in modulating the microbiota, in improving the physico-chemical conditions of the gut and in reducing oxidative stress. It also discusses the mechanisms of probiotics in inhibiting tumour progression, in producing anticancer compounds and in modulating the host immune response. Even though some of these effects were observed in several clinical trials, when probiotic formulations were used as a supplement to CRC therapies, the application of probiotics as biotherapeutics against CRC still needs further investigation.

Microencapsulation for the Therapeutic Delivery of Drugs, Live Mammalian and Bacterial Cells, and Other Biopharmaceutics: Current Status and Future Directions

Microencapsulation is a technology that has shown significant promise in biotherapeutics, and other applications. It has been proven useful in the immobilization of drugs, live mammalian and bacterial cells and other cells, and other biopharmaceutics molecules, as it can provide material structuration, protection of the enclosed product, and controlled release of the encapsulated contents, all of which can ensure efficient and safe therapeutic effects. This paper is a comprehensive review of microencapsulation and its latest developments in the field. It provides a comprehensive overview of the technology and primary goals of microencapsulation and discusses various processes and techniques involved in microencapsulation including physical, chemical, physicochemical, and other methods involved. It also summarizes the state-of-the-art successes of microencapsulation, specifically with regard to the encapsulation of microorganisms, mammalian cells, drugs, and other biopharmaceutics in various diseases. The limitations and future directions of microencapsulation technologies are also discussed.

[Gut microbial influence and probiotics on colorectal cancer]

The human intestinal microbiota is a community of 10(13)-10(14) microorganisms that harbor in the intestine and normally participate in a symbiotic relationship with human. Technical and conceptual advances have enabled rapid progress in characterizing the taxonomic composition, metabolic capacity and immunomodulatory activity of the human intestinal microbiota. Their collective genome, defined as microbiome, is estimated to contain ≥150 times as many genes as 2.85 billion base pair human genome. The intestinal microbiota and its microbiome form a diverse and complex ecological community that profoundly impact intestinal homeostasis and disease states. It is becoming increasingly evident that the large and complex bacterial population of the large intestine plays an important role in colorectal carcinogenesis. Numerous studies show that gut immunity and inflammation have impact on the development of colorectal cancer. Additionally, bacteria have been linked to colorectal cancer by the production of toxic and genotoxic bacterial metabolite. In this review, we discuss the multifactorial role of intestinal microbiota in colorectal cancer and role for probiotics in the prevention of colorectal cancer.

Dairy products and cancer

Cancer is a group of more than 100 diseases in which cells display uncontrolled growth, invasion, and sometimes metastasis. Milk and dairy products contain micronutrients and several bioactive constituents that may influence cancer risk and progression. Much of the focus of human, population-based studies has been on the effects of intake of milk and total dairy products or of calcium intake. Based on a systematic review of the epidemiologic literature, the World Cancer Research Fund and American Institute for Cancer Research report concluded there was a probable association between milk intake and lower risk of colorectal cancer, a probable association between diets high in calcium and increased risk of prostate cancer, and limited evidence of an association between milk intake and lower risk of bladder cancer. For other cancers, the evidence was mixed or lacking. Since the 2007 report, several additional, large-cohort studies have been published, including two that show an inverse association between intake of cultured dairy products and bladder cancer. Little is known about the potential effect of various bioactives produced during rumen microbe metabolism on cancer risk. Furthermore, studies support a role of live microbes present in some dairy products in the modulation of the human gut microbial community and gut metabolism. Given the growing appreciation for the role of the gut microbial community in relation to immune function and health and disease, including cancer, the potential role of various dairy products in the modulation of the human gut microbiome warrants further evaluation. Key teaching points: As a dietary exposure, dairy products are a complex group of foods and composition varies by region, which makes evaluation of their association with disease risk difficult. For most cancers, associations between cancer risk and intake of milk and dairy products have been examined only in a small number of cohort studies, and data are inconsistent or lacking. Meta-analyses of cohort data available to date support an inverse association between milk intake and risk of colorectal and bladder cancer and a positive association between diets high in calcium and risk of prostate cancer. Other constituents of dairy products, such as rumen-derived metabolites, have not been evaluated extensively for cancer-preventive properties. The influence of live microbes in fermented dairy products and certain cheeses on the human gut microbiome and immune function is a growing area of study.

Food formats for effective delivery of probiotics

Probiotic bacteria are increasingly incorporated into food products intended to confer health benefits in the human gut and beyond. Little is known about how the food matrix and product formulation impacts probiotic functionality, even though such information is essential to scientific understanding and regulatory substantiation of health benefits. The food format has the potential to affect probiotic survival, physiology, and potentially efficacy, but few comparative studies in humans have been conducted. Human studies should account for the effects of the food base on human health and the bioactive components present in the foods that may augment or diminish interactions of the probiotic with the human host. Some studies show that food ingredients such as prebiotics and milk components can improve probiotic survival during the shelf life of foods, which may enhance probiotic efficacy through increased dose effects. Furthermore, there are indications that synbiotic products are more effective than either probiotics or prebiotics alone. Identification of probiotic adaptations to the food and gut environments holds promise for determining the specific cell components and potential bacterial-food interactions necessary for health benefits and determining how these factors are affected by changes in food formulation and host diet. These studies, combined with controlled human studies, are important future research activities for advancing this field.

Gut microbiota and probiotics in colon tumorigenesis

The human gastrointestinal tract harbors a complex and abundant microbial community reaching as high as 10(13)-10(14) microorganisms in the colon. This endogenous microbiota forms a symbiotic relationship with their eukaryotic host and this close partnership helps maintain homeostasis by performing essential and non-redundant tasks (e.g. nutrition/energy and, immune system balance, pathogen exclusion). Although this relationship is essential and beneficial to the host, various events (e.g. infection, diet, stress, inflammation) may impact microbial composition, leading to the formation of a dysbiotic microbiota, further impacting on health and disease states. For example, Crohn's disease and ulcerative colitis, collectively termed inflammatory bowel diseases (IBD), have been associated with the establishment of a dysbiotic microbiota. In addition, extra-intestinal disorders such as obesity and metabolic syndrome are also associated with the development of a dysbiotic microbiota. Consequently, there is an increasing interest in harnessing the power of the microbiome and modulating its composition as a means to alleviate intestinal pathologies/disorders and maintain health status. In this review, we will discuss the emerging relationship between the microbiota and development of colorectal cancer as well as present evidence that microbial manipulation (probiotic, prebiotic) impacts disease development.

Oral inoculation of probiotics Lactobacillus acidophilus NCFM suppresses tumour growth both in segmental orthotopic colon cancer and extra-intestinal tissue

Modulation of the cellular response by the administration of probiotic bacteria may be an effective strategy for preventing or inhibiting tumour growth. We orally pre-inoculated mice with probiotics Lactobacillus acidophilus NCFM (La) for 14 d. Subcutaneous dorsal-flank tumours and segmental orthotopic colon cancers were implanted into mice using CT-26 murine colon adenocarcinoma cells. On day 28 after tumour initiation, the lamina propria of the colon, mesenteric lymph nodes (MLN) and spleen were harvested and purified for flow cytometry and mRNA analyses. We demonstrated that La pre-inoculation reduced tumour volume growth by 50·3 %, compared with untreated mice at 28 d after tumour implants (2465·5 (SEM 1290·4) v. 4950·9 (SEM 1689·3) mm³, P<0·001). Inoculation with La reduced the severity of colonic carcinogenesis caused by CT-26 cells, such as level of colonic involvement and structural abnormality of epithelial/crypt damage. Moreover, La enhanced apoptosis of CT-26 cells both in dorsal-flank tumour and segmental orthotopic colon cancer, and the mean counts of apoptotic body were higher in mice pre-inoculated with La (P<0·05) compared with untreated mice. La pre-inoculation down-regulated the CXCR4 mRNA expressions in the colon, MLN and extra-intestinal tissue, compared with untreated mice (P<0·05). In addition, La pre-inoculation reduced the mean fluorescence index of MHC class I (H-2Dd, -Kd and -Ld) in flow cytometry analysis. Taken together, these findings suggest that probiotics La may play a role in attenuating tumour growth during CT-26 cell carcinogenesis. The down-regulated expression of CXCR4 mRNA and MHC class I, as well as increasing apoptosis in tumour tissue, indicated that La may be associated with modulating the cellular response triggered by colon carcinogenesis.

Gut microbiota: next frontier in understanding human health and development of biotherapeutics

The gut microbiota is a remarkable asset for human health. As a key element in the development and prevention of specific diseases, its study has yielded a new field of promising biotherapeutics. This review provides comprehensive and updated knowledge of the human gut microbiota, its implications in health and disease, and the potentials and limitations of its modification by currently available biotherapeutics to treat, prevent and/or restore human health, and future directions. Homeostasis of the gut microbiota maintains various functions which are vital to the maintenance of human health. Disruption of the intestinal ecosystem equilibrium (gut dysbiosis) is associated with a plethora of human diseases, including autoimmune and allergic diseases, colorectal cancer, metabolic diseases, and bacterial infections. Relevant underlying mechanisms by which specific intestinal bacteria populations might trigger the development of disease in susceptible hosts are being explored across the globe. Beneficial modulation of the gut microbiota using biotherapeutics, such as prebiotics, probiotics, and antibiotics, may favor health-promoting populations of bacteria and can be exploited in development of biotherapeutics. Other technologies, such as development of human gut models, bacterial screening, and delivery formulations eg, microencapsulated probiotics, may contribute significantly in the near future. Therefore, the human gut microbiota is a legitimate therapeutic target to treat and/or prevent various diseases. Development of a clear understanding of the technologies needed to exploit the gut microbiota is urgently required.