Spray-drying process preserves the protective capacity of a breast milk-derived Bifidobacterium lactis strain on acute and chronic colitis in mice

The Possible Link Between Manufacturing and Probiotic Efficacy; a Molecular Point of View on Bifidobacterium

Probiotics for food or supplement use have been studied in numerous clinical trials, addressing a broad variety of diseases, and conditions. However, discrepancies were observed in the clinical outcomes stemming from the use of lactobacillaceae and bifidobacteria strains. These differences are often attributed to variations in the clinical trial protocol like trial design, included target population, probiotic dosage, or outcome parameters measured. However, a contribution of the methods used to produce the live bioactive ingredients should not be neglected as a possible additional factor in the observed clinical outcome variations. It is well established that manufacturing conditions play a role in determining the survival and viability of probiotics, but much less is known about their influence on the probiotic molecular composition and functionality. In this review, we briefly summarize the evidence obtained for Lacticaseibacillus rhamnosus GG and Lactiplantibacillus plantarum WCFS1, highlighting that expression and presence of probiotic niche factor (NF) and/or effector molecules (EM) may be altered during production of those two well-characterized lactobacillaceae probiotic strains. Subsequently, we summarize in more depth what is the present state of knowledge about bifidobacterial probiotic NF and EM; how their expression may be modified by manufacturing related environmental factors and how that may affect their biological activity in the host. This review highlights the importance of gathering knowledge on probiotic NF and EM, to validate them as surrogate markers of probiotic functionality. We further propose that monitoring of validated NF and/or EM during production and/or in the final preparation could complement viable count assessments that are currently applied in industry. Overall, we suggest that implementation of molecular level quality controls (i.e., based on validated NF and EM), could provide mode of action based in vitro tests contributing to better control the health-promoting reliability of probiotic products.

Targeted Delivery of Probiotics: Perspectives on Research and Commercialization

Considering the significance of the gut microbiota on human health, there has been ever-growing research and commercial interest in various aspects of probiotic functional foods and drugs. A probiotic food requires cautious consideration in terms of strain selection, appropriate process and storage conditions, cell viability and functionality, and effective delivery at the targeted site. To address these challenges, several technologies have been explored and some of them have been adopted for industrial applicability. Encapsulation of probiotics has been recognized as an effective way to stabilize them in their dried form. By conferring a physical barrier to protect them from adverse conditions, the encapsulation approach renders direct benefits on stability, delivery, and functionality. Various techniques have been explored to encapsulate probiotics, but it is noteworthy that the encapsulation method itself influences surface morphology, viability, and survivability of probiotics. This review focuses on the need to encapsulate probiotics, trends in various encapsulation techniques, current research and challenges in targeted delivery, the market status of encapsulated probiotics, and future directions. Specific focus has been given on various in vitro methods that have been explored to better understand their delivery and performance.

Identification of New Potential Biotherapeutics from Human Gut Microbiota-Derived Bacteria

The role of the gut microbiota in health and disease is well recognized and the microbiota dysbiosis observed in many chronic diseases became a new therapeutic target. The challenge is to get a better insight into the functionality of commensal bacteria and to use this knowledge to select live biotherapeutics as new preventive or therapeutic products. In this study, we set up a screening approach to evaluate the functional capacities of a set of 21 strains isolated from the gut microbiota of neonates and adults. For this purpose, we selected key biological processes involved in the microbiome-host symbiosis and known to impact the host physiology i.e., the production of short-chain fatty acids and the ability to strengthen an epithelial barrier (Caco-2), to induce the release of the anti-inflammatory IL-10 cytokine after co-culture with human immune cells (PBMC) or to increase GLP-1 production from STC-1 endocrine cell line. This strategy highlighted fifteen strains exhibiting beneficial activities among which seven strains combined several of them. Interestingly, this work revealed for the first time a high prevalence of potential health-promoting functions among intestinal commensal strains and identified several appealing novel candidates for the management of chronic diseases, notably obesity and inflammatory bowel diseases.

Breast-milk derived potential probiotics as strategy for the management of childhood obesity

Obesity and overweight, and their concomitant metabolic diseases, emerge as one of the most severe health problems in the world. Prevention and management of obesity are proposed to begin early in childhood, when probiotics may have a role. The Simulator of the Human Intestinal Microbial Ecosystem (SHIME®), in a dynamic validated in vitro system able to simulate the different parts of the gastrointestinal tract, has proven to be useful in analyzing the human intestinal microbial community. L. plantarum 73a and B. animalis subsp. lactis INL1, two strains isolated from breast milk, were assayed in the SHIME® using the fecal microbiota of an obese child. L. plantarum 73a alone or in combination with B. animalis subsp. lactis INL1 demonstrated survival capacity in the SHIME® system. The administration of both strains increased the alpha diversity of the microbiota and reduced the levels of the phylum Proteobacteria. In particular, the genera Escherichia, Shigella, and Clostridium_sensu_stricto_1 were significantly reduced when both strains were administered. The increase of Proteobacteria phylum is generally associated with the microbiota of obese people. Escherichia and Shigellacan be involved in inflammation-dependent adiposity and insulin resistance. L. plantarum73a supplementation reduced ammonia production. L. plantarum 73a alone or in combination with B. animalis subsp. lactis INL1 are potential probiotic candidates for the management of infant obesity.

In Vitro Characterization of Gut Microbiota-Derived Commensal Strains: Selection of Parabacteroides distasonis Strains Alleviating TNBS-Induced Colitis in Mice

Alterations in the gut microbiota composition and diversity seem to play a role in the development of chronic diseases, including inflammatory bowel disease (IBD), leading to gut barrier disruption and induction of proinflammatory immune responses. This opens the door for the use of novel health-promoting bacteria. We selected five Parabacteroides distasonis strains isolated from human adult and neonates gut microbiota. We evaluated in vitro their immunomodulation capacities and their ability to reinforce the gut barrier and characterized in vivo their protective effects in an acute murine model of colitis. The in vitro beneficial activities were highly strain dependent: two strains exhibited a potent anti-inflammatory potential and restored the gut barrier while a third strain reinstated the epithelial barrier. While their survival to in vitro gastric conditions was variable, the levels of P. distasonis DNA were higher in the stools of bacteria-treated animals. The strains that were positively scored in vitro displayed a strong ability to rescue mice from colitis. We further showed that two strains primed dendritic cells to induce regulatory T lymphocytes from naïve CD4⁺ T cells. This study provides better insights on the functionality of commensal bacteria and crucial clues to design live biotherapeutics able to target inflammatory chronic diseases such as IBD.

Bifidobacterium lactis BB-12 Attenuates Macrophage Aging Induced by D-Galactose and Promotes M2 Macrophage Polarization

Immunosenescence comprises a set of dynamic changes occurring in innate and adaptive immune systems, and macrophage aging plays an important role in innate and adaptive immunosenescence. However, function and polarization changes in aging macrophages have not been fully evaluated, and no effective method for delaying macrophage senescence is currently available. The results of this study reveal that D-galactose (D-gal) can promote J774A.1 macrophage senescence and induce macrophage M1 polarization differentiation. Bifidobacterium lactis BB-12 can significantly inhibit J774A.1 macrophage senescence induced by D-gal. IL-6 and IL-12 levels in the BB-12 groups remarkably decreased compared with that in the D-gal group, and the M2 marker, IL-10, and Arg-1 mRNA levels increased in the BB-12 group. BB-12 inhibited the expression of p-signal transducer and activator of transcription 1 (STAT1) and promoted p-STAT6 expression. In summary, the present study indicates that BB-12 can attenuate the J774A.1 macrophage senescence and induce M2 macrophage polarization, thereby indicating the potential of BB-12 to slow down immunosenescence and inflamm-aging.

Novel bifidobacteria strains isolated from nonconventional sources. Technological, antimicrobial and biological characterization for their use as probiotics

AIM

To characterize four novel autochthonous bifidobacteria isolated from monkey faeces and a Bifidobacterium lactis strain isolated from chicken faeces by evaluating their technological and biological/functional potential to be used as probiotics. Different stressors, including food process parameters and storage, can affect their viability and functionality.

METHODS AND RESULTS

The resistance to frozen storage, tolerance to lyophilization and viability during storage, thermal, acidic and simulated gastric resistance, surface hydrophobicity and antimicrobial activity against pathogens were studied. Bifidobacterium lactis Bb12 and INL1 were used as reference strains. The results obtained demonstrated that the new isolates presented strain-dependent behaviour. Good results were obtained for thermal resistance, frozen storage at -80°C and lyophilized powders maintained at 5°C. Cell viability during refrigerated storage was higher when the strains were resuspended in milk at pH 5·0 than at 4·5. The surface hydrophobicity ranged between 7 and 98% depending on the strain. The simulated gastric resistance was improved for the strains incorporated in cheese. Regarding antimicrobial activity, bifidobacteria isolated from monkey presented higher inhibitory capacity than the reference strains.

CONCLUSION

This research provides a deeper insight into new strains of bifidobacteria isolated from primates and chicken that have not been previously characterized for their potential use in dairy products and confirm the most robust stress tolerance of B. lactis.

SIGNIFICANCE AND IMPACT OF THE STUDY

The possibility of expanding the available bifidobacteria with the potential to be added to a probiotic food necessarily implies characterizing them from different points of view, especially when considering unknown species. For monkey isolates (which showed higher antimicrobial activity against pathogens), more in-depth knowledge is needed before applying strategies to improve their performance. On the contrary, the chicken isolate B. lactis P32/1 showed similar behaviour to the references B. lactis strains; therefore, it could be considered as a potential probiotic candidate.

Safety, functional properties and technological performance in whey-based media of probiotic candidates from human breast milk

We aimed at isolating and characterising microorganisms present in human breast milk with probiotic potential. In an 8-week postpartum sampling period, two strains of bifidobacteria (Bifidobacterium longum LM7a and Bifidobacterium dentium LM8a') and four strains of lactobacilli were isolated, all during the first 4-week postpartum. B. longum LM7a and B. dentium LM8a', together with four strains previously isolated from breast milk (Bifidobacterium lactis INL1, INL2, INL4 and INL5), were considered for further studies. Susceptibility of the strains to tetracycline, erythromycin, clindamycin, streptomycin, vancomycin and chloramphenicol was evaluated and the isolates exhibited, in general, the same properties as previously reported for bifidobacteria. All isolates showed low hydrophobicity and B. lactis and B. longum strains had satisfactory resistance to gastric digestion and bile shock, but not to pancreatin. B. lactis INL1, B. longum LM7a and B. dentium LM8a' were selected for some comparative technological studies. In particular, B. lactis INL1 displayed technological potential, with satisfactory growth in cheese whey-based media in biofermentor and resistance to freeze-drying, accelerated storage conditions and simulated gastric digestion.

New probiotic strains for inflammatory bowel disease management identified by combining in vitro and in vivo approaches

Alterations in the gut microbiota composition play a key role in the development of chronic diseases such as inflammatory bowel disease (IBD). The potential use of probiotics therefore gained attention, although outcomes were sometimes conflicting and results largely strain-dependent. The present study aimed to identify new probiotic strains that have a high potential for the management of this type of pathologies. Strains were selected from a large collection by combining different in vitro and in vivo approaches, addressing both anti-inflammatory potential and ability to improve the gut barrier function. We identified six strains with an interesting anti-inflammatory profile on peripheral blood mononuclear cells and with the ability to restore the gut barrier using a gut permeability model based on Caco-2 cells sensitized with hydrogen peroxide. The in vivo evaluation in two 2,4,6-trinitrobenzene sulfonic acid-induced murine models of colitis highlighted that some of the strains exhibited beneficial activities against acute colitis while others improved chronic colitis. Bifidobacterium bifidum PI22, the strain that exhibited the most protective capacities against acute colitis was only slightly efficacious against chronic colitis, while Bifidobacterium lactis LA804 which was less efficacious in the acute model was the most protective against chronic colitis. Lactobacillus helveticus PI5 was not anti-inflammatory in vitro but the best in strengthening the epithelial barrier and as such able to significantly dampen murine acute colitis. Interestingly, Lactobacillus salivarius LA307 protected mice significantly against both types of colitis. This work provides crucial clues for selecting the best strains for more efficacious therapeutic approaches in the management of chronic inflammatory diseases. The strategy employed allowed us to identify four strains with different characteristics and a high potential for the management of inflammatory diseases, such as IBD.

Food-Origin Lactic Acid Bacteria May Exhibit Probiotic Properties: Review

One of the most promising areas of development in the human nutritional field over the last two decades has been the use of probiotics and recognition of their role in human health and disease. Lactic acid-producing bacteria are the most commonly used probiotics in foods. It is well known that probiotics have a number of beneficial health effects in humans and animals. They play an important role in the protection of the host against harmful microorganisms and also strengthen the immune system. Some probiotics have also been found to improve feed digestibility and reduce metabolic disorders. They must be safe, acid and bile tolerant, and able to adhere and colonize the intestinal tract. The means by which probiotic bacteria elicit their health effects are not understood fully, but may include competitive exclusion of enteric pathogens, neutralization of dietary carcinogens, production of antimicrobial metabolites, and modulation of mucosal and systemic immune function. So far, lactic acid bacteria isolated only from the human gastrointestinal tract are recommended by the Food and Agriculture Organization (FAO) and World Health Organization (WHO) for use as probiotics by humans. However, more and more studies suggest that strains considered to be probiotics could be isolated from fermented products of animal origin, as well as from non-dairy fermented products. Traditional fermented products are a rich source of microorganisms, some of which may exhibit probiotic properties. They conform to the FAO/WHO recommendation, with one exception; they have not been isolated from human gastrointestinal tract. In light of extensive new scientific evidence, should the possibility of changing the current FAO/WHO requirements for the definition of probiotic bacteria be considered?

Lactobacillus reuteri F-9-35 Prevents DSS-Induced Colitis by Inhibiting Proinflammatory Gene Expression and Restoring the Gut Microbiota in Mice

Probiotics are considered to be a potential treatment for ulcerative colitis (UC). The aim of this study was to compare the preventive effect of a space flight-induced mutant L. reuteri F-9-35 and its wild type on UC in vivo. Female mice were randomly assigned to five groups: one normal and four colitic. Mice from colitis groups were daily gavaged with 0.2 mL 12% (w/v) skim milk containing the mutant or wild type (1 × 10¹¹ CFU/mL), skim milk alone or distilled water for the whole experiment period, starting 7 days before colitis induction. UC was induced by administrating mice with 3.5% (w/v) dextran sulfate sodium (DSS) in drinking water for 7 days, after which DSS was removed and maintained for 3 days as a recovery phase. The results showed that the mice fed with L. reuteri F-9-35 had less inflammatory phenotype according to macroscopic and histological analysis, reduced myeloperoxidase activity, and lower expression of proinflammatory genes (Tumor necrosis factor-α, cyclooxygenase-2 and interleukin-6) in colonic tissue compared with control. Furthermore, L. reuteri F-9-35 protected the mice from gut microbiota dysbiosis from DDS induced colitis. Neither wild type nor the milk alone had such beneficial effects. From above we conclude that L. reuteri F-9-35 has great potential in the prevention of UC as a dietary supplement.

PRACTICAL APPLICATION

Ulcerative colitis (UC) is the most common inflammatory bowel diseases and there is still a lack of safe and effective treatments. Consumption of L. reuteri F-9-35 may effective in preventing human UC.

Upregulation of Intestinal Barrier Function in Mice with DSS-Induced Colitis by a Defined Bacterial Consortium Is Associated with Expansion of IL-17A Producing Gamma Delta T Cells

Bacterial consortium transplantation (BCT) is a promising alternative to fecal microbiota transplantation in treating inflammatory bowel disease (IBD). Here, we showed that a defined bacterial consortium derived from healthy mice was able to enhance the intestinal barrier function of mice with dextran sulfate sodium (DSS)-induced colitis. Interestingly, we found that the bacterial consortium significantly promoted the expansion of IL-17A-producing γδT (γδT17) cells in colonic lamina propria, which was closely associated with changing of intestinal microbial composition. The increased IL-17A secretion upon treatment with microbial products derived from the bacterial consortium was accompanied with upregulation of TLR2 expression by γδT cells, and it might be responsible for the upregulation of mucosal barrier function through IL-17R-ACT1-mediated recovery of the disrupted occludin subcellular location. Changing of some specific microbial groups such as Bifidobacterium and Bacillus spp. was closely correlated with the promotion of TLR2⁺ γδT cells. Our results support that BCT can restore the alliance between commensal microbiota and intestinal γδT cells, which contributes to the improvement of intestinal barrier function. This study provides new insight into the development of bacteria transplantation therapy for the treatment of IBD.