Survival of lactic acid bacteria in a dynamic model of the stomach and small intestine: validation and the effects of bile

Postbiotic potential of Lactococcus lactis CNCM I-5388 in alleviating visceral pain in female rat through GABA production: The innovative concept of the "active-GAD bag"

Irritable bowel syndrome (IBS) is a multifactorial disorder of the gut-brain axis, characterized by visceral hypersensitivity (VH). Psychobiotics, through GABA synthesis, are good candidates to alleviate gastrointestinal discomfort. Here, we analyzed the GABA-producer Lactococcus lactis CNCM I-5388 as an active-enzyme postbiotic to relieve VH mediated by psychological stress. L. lactis CNCM I-5388 was inactivated by ethanol while maintaining its glutamate decarboxylase (GAD) activity. This EtOH-treated nonviable form was given daily orally for 1, 5, or 10 days to female Wistar rats in comparison with viable L. lactis CNCM I-5388 or vehicle. Visceral sensitivity was measured by electromyography before and after partial restraint stress (PRS). GABA was quantified in the stomach collected from rats and in the gastric compartment of TIM-1 human gut model in fed state. A daily treatment for 5 and 10 days by L. lactis CNCM I-5388 both in its viable and nonviable forms counteracted VH promoted by PRS. However, only viable L. lactis CNCM I-5388 tended to reduce VH after a single administration. After 5-day treatment, only under PRS conditions, the production of GABA within the stomach was enhanced in rats treated with viable or nonviable L. lactis CNCM I-5388. This increase was confirmed by using the TIM-1 human gut model. We found that a postbiotic with an active-GAD enzyme of L. lactis CNCM I-5388, similarly to its viable psychobiotic form, exerts anti-VH properties in an IBS-like rat model. These effects are associated with GABA production in the stomach where the low pH promotes GAD activity.

Sheep-Derived Lactobacillus johnsonii M5 Enhances Immunity and Antioxidant Capacity, Alleviates Diarrhea, and Improves Intestinal Health in Early-Weaned Lambs

The early weaning of lambs frequently leads to weakened immunity, impaired intestinal function, and increased susceptibility to intestinal disease. Lactobacillus plays a role in regulating immunity, enhancing antioxidant capacity, and maintaining intestinal health. This study aims to isolate a strain of Lactobacillus with favorable probiotic properties from sheep feces and investigate its effects on the intestinal health of early-weaned lambs. In this study, the growth characteristics, acid production capacity, bacteriostatic capacity, bile salt tolerance, gastrointestinal fluid tolerance, self-coagulation capacity, and surface hydrophobicity of Lactobacillus isolated from sheep feces were analyzed for in vitro probiotic properties. Lactobacilli with strong probiotic properties were used for in vivo validation. A total of 72 Hu lambs were allocated into four groups: a ewe-reared group (ER), early-weaning group (EW), low-dose Lactobacillus group (LL), and high-dose Lactobacillus group (HL). Early weaning was performed in the EW, LL, and HL groups at the age of 28 days. Lactobacillus johnsonii M5 (L. johnsonii M5), isolated from sheep feces, exhibited strong probiotic properties in vitro. Feeding EW lambs with a low dose of L. johnsonii M5 significantly reduced their diarrhea rate (p < 0.05). Its supplementation increased the levels of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) in serum and jejunal mucosa and decreased levels of malondialdehyde (MDA) (p < 0.05). Compared to the EW group, serum immunoglobulin G (IgG) levels were significantly increased in the LL group (p < 0.05). Compared to the EW group, feeding with L. johnsonii M5 increased the content of anti-inflammatory cytokines, while reducing the content of pro-inflammatory cytokines in serum and jejunal mucosa (p < 0.05). Feeding early-weaned lambs with L. johnsonii M5 also decreased jejunal crypt depth and increased occludin and claudin-1 in jejunal mucosa (p < 0.05). These findings indicate that feeding early-weaned lambs with L. johnsonii M5 enhances their immunity and antioxidant capacity, improving intestinal health, and mitigates diarrhea in early-weaned lambs.

Delivery of Probiotic-Loaded Microcapsules in the Gastrointestinal Tract: A Review

Probiotics are live microorganisms that inhabit the gastrointestinal tract and confer health benefits to consumers. However, a sufficient number of viable probiotic cells must be delivered to the specific site of interest in the gastrointestinal tract to exert these benefits. Enhanced viability and tolerance to sublethal gastrointestinal stress can be achieved using appropriate coating materials and food matrices for orally consumed probiotics. The release mechanism and interaction of probiotic microcapsules with the gastrointestinal tract have been minimally explored in the literature to date. To the authors' knowledge, no review has been published to discuss the nature of release and the challenges in the targeted delivery of probiotics. This review addresses gastrointestinal-related complications in the formulation of targeted delivery and controlled release of probiotic strains. It investigates the impacts of environmental stresses during the transition stage and delivery to the target region in the gastrointestinal tract. The influence of factors such as pH levels, enzymatic degradation, and redox conditions on the release mechanisms of probiotics is presented. Finally, the available methods to evaluate the efficiency of a probiotic delivery system, including in vitro and in vivo, are reviewed and assessed. The paper concludes with a discussion highlighting the emerging technologies in the field and emphasising key areas in need of future study.

Rheological, microbiological, and in vitro digestive properties of Kefir produced with different Kefir grains and commercial starter cultures

This research investigates the production of kefir using Turkish and Kazakh kefir grains and commercial starter cultures, followed by storage at 4 °C for 30 days. The study monitors the rheological properties and microbiological characteristics of kefir on the 1st, 15th, and 30th days of storage, as well as during dynamic in vitro gastrointestinal digestion. Kefir samples were passed through a dynamic in vitro gastrointestinal model simulating the digestive processes of the mouth, stomach, and small intestine which was designed in laboratory conditions. Kefir from Turkish kefir grain exhibited the lowest average titratable acidity, apparent viscosity, and flow behavior index, while kefir from Kazakh kefir grain had the highest average pH. Over the storage period, pH and flow behavior index decreased, while titratable acidity, viscosity, and consistency coefficient increased. The kefir samples showed non-Newtonian pseudoplastic flow characteristics. The acetic acid bacteria and Leuconostoc counts of kefir samples produced with commercial starter cultures were higher than those produced with kefir grains, while yeast counts were higher in kefir samples produced with kefir grains. During storage and in vitro gastrointestinal digestion, the number of microorganisms in kefir samples decreased. Turkish kefir grain resulted in the lowest reduction (%) of microorganism counts during in vitro gastrointestinal digestion. These findings shed light on the rheological, microbiological, and in vitro digestive properties of kefir during storage, which may contribute to improving the quality and health benefits of kefir products. The present study revealed that the kefir produced with kefir grains had a lower decrease in the viability of microorganisms compared to the kefir produced with starter culture after passage through the gastrointestinal model, so kefir produced with kefir grains may be more preferred due to its possible health benefits.

In Vitro Cholesterol Uptake by the Microflora of Selected Kefir Starter Cultures

Kefir, a fermented milk beverage, is recognized for its potential health benefits, including its cholesterol-lowering properties. This study demonstrated that selected kefir starter cultures, including Lactococcus strains and yeasts, significantly reduce cholesterol-binding capacity under simulated gastrointestinal conditions, underscoring the challenges of probiotic delivery. We compared the performance of these cultures under laboratory conditions (growth broths) and simulated digestive juice models. Lactococcus strains showed significant differences in cholesterol binding between the two environments, highlighting the limitations of relying solely on laboratory testing. Yeast cultures also exhibited greater cholesterol binding in their native broths, but their survival was limited in digestive models. Our findings suggest that effective probiotic formulations should prioritize strains with high cholesterol-binding capacity and robust survival rates throughout the digestive tract. This study provides valuable insights for future research on the mechanisms behind these functionalities and the potential of kefir yeast strains for use in human digestive models. Our results can be used to inform the development of improved probiotic formulations for cholesterol management.

Effects of Lactobacillus spp. on Helicobacter pylori: A Promising Frontier in the Era of Antibiotic Resistance

Helicobacter pylori, a pathogenic bacterium responsible for multiple gastrointestinal disorders, has emerged as a major global concern due to rise in antibiotic resistance. Unwanted side effects of antibiotics therapy are further complicating the treatment strategies. Consequently, an alternative approach, using probiotics has emerged as a promising solution for treating H. pylori infections. Probiotics have shown considerable potential in increasing the cure rate and reducing the side effects through diverse mechanisms. Among the widely employed probiotics, Lactobacillus spp. has garnered particular attention in this review. After reviewing the studies on effects of Lactobacillus spp. on H. pylori, it is evident that several Lactobacillus spp. have demonstrated their potential efficacy against H. pylori infection, when administered alone or in conjunction with antibiotics, in a strain-specific manner. Furthermore, the inclusion of Lactobacillus spp. in the treatment regimen has also been associated with a reduction in the side effects related to antibiotic-based therapies. Future research may focus on identifying optimal strains and treatment regimens, understanding the long-term impacts of use, and determining their role in preventing H. pylori infection in various populations.

Assessing food digestion in the elderly using in vitro gastrointestinal models

With the global population of individuals aged 65 and older projected to exceed 1.5 billion by 2050, understanding the impact of aging on digestion and nutrient absorption is essential for addressing the nutritional needs of the elderly. This review explores the limitations of traditional in vivo studies and underscores the growing importance of in vitro gastrointestinal models as an ethical and cost-effective alternative for investigating digestion in the elderly. The review provides a comprehensive analysis of age-related physiological changes in the gastrointestinal tract (GIT), and critically evaluates how static and dynamic in vitro models have been adapted to simulate these changes. We also discuss the significant challenges these models face in accurately replicating the complexities of elderly digestion, particularly in mimicking the interactions between digestive processes and the gut microbiome. By addressing these challenges, particularly through the development of more physiologically relevant and personalized in vitro models, this review highlights the potential to enhance our understanding of elderly digestion and improve nutritional strategies, ultimately contributing to better health outcomes for the aging population.

Exploring the Potential Probiotic Properties of Bifidobacterium breve DSM 32583-A Novel Strain Isolated from Human Milk

Human milk is the best nutrition for infants, providing optimal support for the developing immune system and gut microbiota. Hence, it has been used as source for probiotic strain isolation, including members of the genus Bifidobacterium, in an effort to provide beneficial effects to infants who cannot be exclusively breastfed. However, not all supplemented bifidobacteria can effectively colonise the infant gut, nor confer health benefits to the individual infant host; therefore, new isolates are needed to develop a range of dietary products for this specific age group. Here, we investigated the beneficial potential of Bifidobacterium breve DSM 32583 isolated from human milk. We show that in vitro B. breve DSM 32583 exhibited several characteristics considered fundamental for beneficial bacteria, including survival in conditions simulating those present in the digestive tract, adherence to human epithelial cell lines, and inhibition of growth of potentially pathogenic microorganisms. Its antibiotic resistance patterns were comparable to those of known beneficial bifidobacterial strains, and its genome did not contain plasmids nor virulence-associated genes. These results suggest that B. breve DSM 32583 is a potential probiotic candidate.

Characterization of a Ligilactobacillus salivarius Strain Isolated from a Cheese Seal Which Was Last Used in 1936

Cheesemaking played a pivotal role in the life of the Pyrenean villages where cheese was a most prized commodity and the subject of much local competition. In one of them (Sasa de Sobrepuerto), Mrs. Sebastiana Palacio decided in 1877 to label all the cheeses made in her household with a seal to differentiate them from those made by other local producers. The cheese seal was last used in 1936 and, since then, it has been kept under excellent storage conditions. Since well-preserved cheese seals are rare, and bacterial cells may survive desiccation for long periods, the objective of this work was to isolate and characterize any lactic acid bacteria that survived in the seal. Analysis of the milky crust material revealed the presence of sheep caseins. Culture-based analysis led to the isolation of a strain of Bacillus licheniformis and a strain of Ligilactobacillus salivarius (L. salivarius SP36). The latter was characterized in vitro for safety and dairy-related functional properties. Its genome encodes several genes involved in protein, peptide, and amino acid catabolism, and flavor. Overall, the phenotypic and genetic features of this strain support a high potential for being used as adjunct culture in cheesemaking.

AG1®, a Novel Synbiotic, Maintains Gut Barrier Function following Inflammatory Challenge in a Caco-2/THP1-Blue™ Co-Culture Model

Nutritional interventions to reduce gastrointestinal (GI) permeability are of significant interest to physically active adults and those experiencing chronic health conditions. This in vitro study was designed to assess the impact of AG1, a novel synbiotic, on GI permeability following an inflammatory challenge. Interventions [AG1 (vitamins/minerals, pre-/probiotics, and phytonutrients) and control (control medium)] were fed separately into a human GI tract model (stomach, small intestine, and colon). In the colonic phase, the GI contents were combined with fecal inocula from three healthy human donors. GI permeability was evaluated with transepithelial electrical resistance (TEER) in a Caco-2 (apical)/THP1-Blue™ (basolateral) co-culture model. The apical side received sodium butyrate (positive control) or Caco-2 complete medium (negative control) during baseline testing. In the 24 h experiment, the apical side received colonic simulation isolates from the GI model, and the basolateral side was treated with Caco-2 complete medium, then 6 h treatment with lipopolysaccharide. TEER was assessed at 0 h and 24 h, and inflammatory markers were measured at 30 h in triplicate. Paired samples t-tests were used to evaluate endpoint mean difference (MD) for AG1 vs. control. TEER was higher for AG1 (mean ± SD: 99.89 ± 1.32%) vs. control (mean ± SD: 92.87 ± 1.22%) following activated THP1-induced damage [MD: 7.0% (p < 0.05)]. AG1 maintained TEER similar to the level of the negative control [-0.1% (p = 0.02)]. No differences in inflammatory markers were observed. These in vitro data suggest that acute supplementation with AG1 might stimulate protective effects on GI permeability. These changes may be driven by SCFA production due to the pre-/probiotic properties of AG1, but more research is needed.

Determination of the Viability of Lactic Acid Bacteria by Dynamic In Vitro Gastrointestinal Model in Household and Industrial-Type Kefir Samples

This study presents results based on differences in the antioxidant activity and lactic acid bacteria counts in different parts of the digestive tract following simulated gastrointestinal digestion of kefir samples. Statistically significant differences were observed in Lactobacillus counts in different kefir types including industrial (IK), starter culture (SCK), and kefir grains (KG). These differences were observed between the initial and second min in the mouth region (T = 3.968; p < 0.05); and between the initial, 60th, and 120th min in the stomach region (R = 11.146; p < 0.05). Additionally, a statistically significant difference was noted in the initial Lactobacillus levels among the IK, SCK, and KG in the stomach region (H = 7.205; p < 0.05). Also, significant differences were identified between the Lactococcus counts of IK across 0, 60, and 120 min in the stomach region (R = 10.236; p < 0.05). Notably, a statistically significant difference was noted in the Lactococcus levels in the KG between the initial and second min in the mouth region (T = 3.101; p < 0.05) and between 0, 60, and 120 min in the stomach region (R = 25.771; p < 0.001). These findings highlight the differences between the physicochemical characteristics of different kefir types. A decrease in lactic acid bacteria counts in kefir samples was observed throughout the dynamic in vitro gastrointestinal tract to reveal the significance of the digestive process when determining probiotic product capacity.

Enhancing Bioaccessibility of Plant Protein Using Probiotics: An In Vitro Study

As plant-based diets become more popular, there is an interest in developing innovations to improve the bioaccessibility of plant protein. In this study, seven probiotic strains (Bifidobacterium animalis subsp. lactis B420, B. lactis Bl-04, Lactobacillus acidophilus NCFM, Lacticaseibacillus rhamnosus HN001, Lacticaseibacillus paracasei subsp. paracasei Lpc-37, Lactiplantibacillus plantarum Lp-115, and Lactococcus lactis subsp. lactis Ll-23) were evaluated for their capacity to hydrolyze soy and pea protein ingredients in an in vitro digestion model of the upper gastrointestinal tract (UGIT). Compared to the control digestion of protein without a probiotic, all the studied strains were able to increase the digestion of soy or pea protein, as evidenced by an increase in free α-amino nitrogen (FAN) and/or free amino acid concentration. The increase in FAN varied between 13 and 33% depending on the protein substrate and probiotic strain. The survival of probiotic bacteria after exposure to digestive fluids was strain-dependent and may have affected the strain's capacity to function and aid in protein digestion in the gastrointestinal environment. Overall, our results from the standardized in vitro digestion model provide an approach to explore probiotics for improved plant protein digestion and bioaccessibility of amino acids; however, human clinical research is needed to evaluate the efficacy of probiotics on amino acid absorption and bioavailability in vivo.

Cytotoxic effect of potential probiotic Lactiplantibacillus plantarum KUMS-Y8 isolated from traditional dairy samples on the KB and OSCC human cancer cell lines

Oral cancer is one of the leading causes of death worldwide, and its prevalence is especially high in developing countries. As an oral cancer treatment, traditional therapies are commonly used. Nonetheless, these treatments frequently result in a variety of side effects. As a consequence, there is an urgent need to enhance oral cancer therapies. Probiotics have recently demonstrated intriguing properties as therapeutic options for cancer treatment. Thus, the purpose of this study was to investigate the anticancer effect of probiotic Lactobacillus strains on the mouth epidermal carcinoma cells (KB) and oral squamous cell carcinoma (OSCC) cell lines. In this study, we looked at 21 Lactobacillus strains isolated from traditional dairy products in the Kermanshah province of western Iran to see if they had any inhibitory effects on oral cancer cell lines in vitro. We isolated and characterized Lactobacillus strains before assessing and comparing their probiotic potential and safety. Using the MTT assay, the bacterial extract was then prepared and used as an anti-proliferative agent on oral cancer (KB and OSCC) and normal (fibroblast and human umbilical vein endothelial cells (HUVEK) cell lines. Finally, acridine orange/ethidium bromide staining was used to determine whether cell death was caused by apoptosis. Four Lactobacillus isolates (C14, M22, M42, and Y8) were shown to have beneficial probiotic qualities. Lactobacillus extracts (of a protein nature) decreased the survival and proliferation of the KB and OSCC cancer cell lines (dose- and time-dependent) by inducing apoptosis, with no basic damaging effects on normal cells. The staining with acridine orange/ethidium bromide revealed that the cell death was caused by apoptosis. Furthermore, of the four Lactobacillus strains examined, isolate Y8 (Lactiplantibacillus plantarum) showed the strongest probiotic potential for suppressing KB and OSCC cell proliferation when compared to anticancer medicines (doxorubicin and paclitaxel). The current research found that Lactobacillus extract might reduce the growth and viability of the KB and OSCC cancer cell lines by inducing apoptosis, increasing the survival rate of oral cancer patients.

Biomaterials and Encapsulation Techniques for Probiotics: Current Status and Future Prospects in Biomedical Applications

Probiotics have garnered significant attention in recent years due to their potential advantages in diverse biomedical applications, such as acting as antimicrobial agents, aiding in tissue repair, and treating diseases. These live bacteria must exist in appropriate quantities and precise locations to exert beneficial effects. However, their viability and activity can be significantly impacted by the surrounding tissue, posing a challenge to maintain their stability in the target location for an extended duration. To counter this, researchers have formulated various strategies that enhance the activity and stability of probiotics by encapsulating them within biomaterials. This approach enables site-specific release, overcoming technical impediments encountered during the processing and application of probiotics. A range of materials can be utilized for encapsulating probiotics, and several methods can be employed for this encapsulation process. This article reviews the recent advancements in probiotics encapsulated within biomaterials, examining the materials, methods, and effects of encapsulation. It also provides an overview of the hurdles faced by currently available biomaterial-based probiotic capsules and suggests potential future research directions in this field. Despite the progress achieved to date, numerous challenges persist, such as the necessity for developing efficient, reproducible encapsulation methods that maintain the viability and activity of probiotics. Furthermore, there is a need to design more robust and targeted delivery vehicles.

Exploring the Cholesterol-Modifying Abilities of Lactobacilli Cells in Digestive Models and Dairy Products

This study aimed to investigate the ability of lactic acid bacteria to remove cholesterol in simulated gastric and intestinal fluids. The findings showed that the amount of cholesterol removed was dependent on the biomass, viability, and bacterial strain. Some cholesterol binding was stable and not released during gastrointestinal transit. The presence of cholesterol affected the fatty acid profile of bacterial cells, potentially influencing their metabolism and functioning. However, adding cholesterol did not significantly impact the survival of lactic acid bacteria during gastrointestinal transit. Storage time, passage, and bacterial culture type did not show significant effects on cholesterol content in fermented dairy products. Variations in cell survival were observed among lactic acid bacteria strains in simulated gastric and intestinal fluids, depending on the environment. Higher milk protein content was found to be more protective for bacterial cells during gastrointestinal transit than fat content. Future research should aim to better understand the impact of cholesterol on lactic acid bacteria metabolism and identify potential health benefits.

Experimental and computational models to investigate intestinal drug permeability and metabolism

Oral administration is the preferred route for drug administration that leads to better therapy compliance. The intestine plays a key role in the absorption and metabolism of oral drugs, therefore, new intestinal models are being continuously proposed, which contribute to the study of intestinal physiology, drug screening, drug side effects, and drug-drug interactions.Advances in pharmaceutical processes have produced more drug formulations, causing challenges for intestinal models. To adapt to the rapid evolution of pharmaceuticals, more intestinal models have been created. However, because of the complexity of the intestine, few models can take all aspects of the intestine into account, and some functions must be sacrificed to investigate other areas. Therefore, investigators need to choose appropriate models according to the experimental stage and other requirements to obtain the desired results.To help researchers achieve this goal, this review summarised the advantages and disadvantages of current commonly used intestinal models and discusses possible future directions, providing a better understanding of intestinal models.

Effect of Probiotics in Breast Cancer: A Systematic Review and Meta-Analysis

Probiotics may have the potential to protect against breast cancer, partly through systemic immunomodulatory action and active impact upon intestinal microbiota. Given a few clinical studies on their curative role, we conducted a systematic review of the potential effects of probiotics in breast cancer patients and survivors of breast cancer, aiming to support further clinical studies. A literature search was performed using PubMed, Embase, and the CENTRAL databases from inception through to March 2022. A total of eight randomized clinical trials were identified from thirteen articles published between 2004 and 2022. We evaluated quality-of-life measures, observed bacterial species and diversity indices, probiotic-related metabolites, inflammatory biomarkers, and other responses in breast cancer patients and survivors. Results were synthesized qualitatively and quantitatively using random-effects meta-analysis. Different probiotics supplements utilized included Lactobacillus species alone (Lacto), with or without estriol; probiotic combinations of Lactobacillus with Bifidobacterium (ProLB), with or without prebiotic fructooligosaccharides (FOS); ProLB plus Streptococcus and FOS (ProLBS + FOS); and ProLB plus Enterococcus (ProLBE). We found that use of ProLBS with FOS in breast cancer patients and use of ProLBE in survivors of breast cancer show potential benefits in countering obesity and dyslipidemia. ProLBS with FOS use decreases pro-inflammatory TNF-α in breast cancer survivors and improves quality of life in those with breast-cancer-associated lymphedema. Supplementing probiotics capsules (10⁹ CFU) with a prebiotic and using an intake duration of 10 weeks could provide a better approach than probiotics alone.

Immunomodulation of the Vaginal Ecosystem by Ligilactobacillus salivarius CECT 30632 Improves Pregnancy Rates among Women with Infertility of Unknown Origin or Habitual Abortions

In this study, the probiotic potential of Ligilactobacillus salivarius CECT 30632 was assessed, including properties specifically related with gynecological targets. This strain displayed co-aggregative and antimicrobial activity against a wide spectrum of vaginal pathogens while being respectful with the growth of vaginal lactobacilli. The strain produced a high concentration of lactic acid and displayed α-amylase activity when assayed in vitro. It showed a noticeable survival rate after exposition to conditions similar to those present in the human digestive tract and was adhesive to both vaginal and intestinal cells. Subsequently, their capacity to increase pregnancy rates among women with habitual abortion or infertility of unknown origin was studied. Administration of L. salivarius CECT 30632 (~9 log₁₀ CFU) daily for a maximum of six months to these women was safe and led to a successful pregnancy rate of 67.5% (80% and 55% for women with repetitive abortion and infertile women, respectively). Significant differences in Nugent score, vaginal pH, and vaginal concentrations of lactobacilli, TGF-β, and VEFG were observed when the samples collected before the intervention were compared with those collected after the treatment among those women who got pregnant. Therefore, this strain can modulate the vaginal ecosystem and lead to better fertility outcomes.

Microbiota in the stomach and application of probiotics to gastroduodenal diseases

The stomach is a hostile environment for most microbes because strong gastric acid kills indigenous microorganisms. Thus, the mass of indigenous microbes detected by traditional culturing method in a highly acidic stomach is reported to be very small. However, in a stomach with less acidity due to atrophic changes of the gastric mucosa, the number of live gastric microbiota dramatically increases and their composition changes. A probiotic is defined as a live microorganism that, when administered in adequate amounts, confers a health benefit on the host. The administration of probiotics to the stomach has thus far been considered impractical, mainly due to the strong acidity in the stomach. The identification of candidate probiotic strains with sufficient resistance to acidity and the ability to achieve close proximity to the gastric mucosa could enable the application of probiotics to the stomach. The utilization of probiotics alone for Helicobacter pylori (H. pylori) infection significantly improves gastric mucosal inflammation and decreases the density of H. pylori on the mucosa, although complete eradication of H. pylori has not yet been demonstrated. The use of probiotics in combination with antimicrobial agents significantly increases the H. pylori eradication rate, especially when the H. pylori strains are resistant to antimicrobial agents. While H. pylori has been considered the most important pathogenic bacterium for the development of gastric cancer, bacteria other than H. pylori are also suggested to be causative pathogens that promote the development of gastric cancer, even after the eradication of H. pylori. Increased non-H. pylori Gram-negative bacteria in the stomach with weak acidity accompanying atrophic gastritis may perpetuate gastric mucosal inflammation and accelerate carcinogenic progression, even after H. pylori eradication. Probiotics restore the acidity in this stomach environment and may therefore prevent the development of gastric cancer by termination of Gram-negative bacteria-induced inflammation. Functional dyspepsia (FD) is defined as the presence of symptoms that are thought to originate in the gastroduodenal region in the absence of any organic, systematic or metabolic diseases. Accumulating evidence has pointed out the duodenum as a target region underlying the pathophysiology of FD. A randomized placebo-controlled clinical trial using a probiotic strain (LG21) demonstrated a significant improving effect on major FD symptoms. One of the possible mechanisms of this effect is protection of the duodenal mucosa from injurious intestinal bacteria through the resolution of small intestinal bacterial over growth.

Current in Vitro and Animal Models for Understanding Foods: Human Gut-Microbiota Interactions

The food-gut microbiota interaction is an important regulator of human health. Numerous in vitro and animal models have thus been developed in order to simulate the specific food-gut microbiota and/or host-gut microbiota interactions in the human colon. This review summarizes the design principles of each model and discusses their advantages and weaknesses in terms of studying food-gut microbiota interactions. In vitro fermentation models appear to be reliable methods to investigate various aspects involved in the food-gut microbiota interactions in humans. However, many physiological perspectives lack appreciation of these models, such as peristaltic movement, biochemical conditions, and gastrointestinal anatomy. Animal models provide more physiological relevance to human trials compared to in vitro models. However, they may have gastrointestinal tract aspects that are distinct from human subjects. This review contains important information that can help the development of more advanced models to study food-gut microbiota interactions in humans.

Characterization and evaluation of anti-Salmonella enteritidis activity of indigenous probiotic lactobacilli in mice

Lactobacilli (n = 24), isolated from human infants and yogurt, showed variable in vitro activity against Salmonella enteritidis (8.0 ± 1.0 to 16.6 ± 0.5 mm) and other gut pathogens (9.0 ± 1.0 to 15.3 ± 0.5 mm), as determined by a well diffusion assay. The isolates were identified as Limosilactobacillus fermentum (FY1, FY3, FY4, IL2, and IL5), Lactobacillus delbrueckii (FY6 and FY7), Lactobacillus sp. (IL7), and Lactobacillus gasseri (IL12). All isolates showed variable in vitro tolerance to acidic pH for 3 h and visible growth at pH 4 and in the presence of 0.3% ox-bile. The antibiotic susceptibility profile of Lactobacillus isolates indicated resistance against vancomycin, ciprofloxacin, streptomycin, and lincomycin. Isolates had variable auto-aggregation and showed variable capabilities to co-aggregate with S. enteritidis. Based on all tested parameters, L. fermentum IL2, L. fermentum IL5, and L. gasseri IL12 were selected for co-culture experiments, followed by in vivo evaluation in Balb/c mice. All the selected isolates resulted in a 100% reduction in S. enteritidis in broth. Lactobacillus isolates efficiently colonized mouse guts and inhibited S. enteritidis colonization. Overall, there was ≥99.06% and ≤4.32 Mean log₁₀ reduction in Salmonella counts in mice feces within 7 days. The study, thus, provided characterized lactobacilli that could be considered as potential ingredients for probiotic formulations intended to prevent S. enteritidis infection in humans.

Yoghurt consumption is associated with changes in the composition of the human gut microbiome and metabolome

BACKGROUND

Yoghurt contains live bacteria that could contribute via modulation of the gut microbiota to its reported beneficial effects such as reduced body weight gain and lower incidence of type 2 diabetes. To date, the association between yoghurt consumption and the composition of the gut microbiota is underexplored. Here we used clinical variables, metabolomics, 16S rRNA and shotgun metagenomic sequencing data collected on over 1000 predominantly female UK twins to define the link between the gut microbiota and yoghurt-associated health benefits.

RESULTS

According to food frequency questionnaires (FFQ), 73% of subjects consumed yoghurt. Consumers presented a healthier diet pattern (healthy eating index: beta = 2.17 ± 0.34; P = 2.72x10-10) and improved metabolic health characterised by reduced visceral fat (beta = -28.18 ± 11.71 g; P = 0.01). According to 16S rRNA gene analyses and whole shotgun metagenomic sequencing approach consistent taxonomic variations were observed with yoghurt consumption. More specifically, we identified higher abundance of species used as yoghurt starters Streptococcus thermophilus (beta = 0.41 ± 0.051; P = 6.14x10-12) and sometimes added Bifidobacterium animalis subsp. lactis (beta = 0.30 ± 0.052; P = 1.49x10-8) in the gut of yoghurt consumers. Replication in 1103 volunteers from the LifeLines-DEEP cohort confirmed the increase of S. thermophilus among yoghurt consumers. Using food records collected the day prior to faecal sampling we showed than an increase in these two yoghurt bacteria could be transient. Metabolomics analysis revealed that B. animalis subsp. lactis was associated with 13 faecal metabolites including a 3-hydroxyoctanoic acid, known to be involved in the regulation of gut inflammation.

CONCLUSIONS

Yoghurt consumption is associated with reduced visceral fat mass and changes in gut microbiome including transient increase of yoghurt-contained species (i.e. S. thermophilus and B. lactis).

Assessing Viability and Stress Tolerance of Probiotics—A Review

The interest in probiotics has increased rapidly the latest years together with the global market for probiotic products. Consequently, establishing reliable microbiological methods for assuring the presence of a certain number of viable microorganisms in probiotic products has become increasingly important. To assure adequate numbers of viable cells, authorities are enquiring for information on viability rates within a certain shelf-life in colony forming units (CFU). This information is obtained from plate count enumeration, a method that enables detection of bacterial cells based on their ability to replicate. Although performing plate count enumeration is one manner of assessing viability, cells can still be viable without possessing the ability to replicate. Thus, to properly assess probiotic viability, further analysis of a broader group of characteristics using several types of methods is proposed. In addition to viability, it is crucial to identify how well the cells in a probiotic product can survive in the gastrointestinal tract (GIT) and thus be able to mediate the desired health benefit while passing through the human body. A broad spectrum of different assay designs for assessing probiotic gastric tolerance have been used in research and quality control. However, the absence of any consensus on how to assess these qualities makes it difficult to compare between laboratories and to translate the results into in vivo tolerance. This review presents and discusses the complexity of assuring that a probiotic is suitable for beneficial consumption. It summarizes the information that can be subtracted from the currently available methods for assessment of viability and stress tolerance of a probiotic, hereby altogether defined as “activity.” Strengths and limitations of the different methods are presented together with favorable method combinations. Finally, the importance of choosing a set of analyses that reveals the necessary aspects of probiotic activity for a certain product or application is emphasized.

Evaluation of tolerance to artificial gastroenteric juice and fermentation characteristics of Lactobacillus strains isolated from human

Fifty-seven strains of Lactobacillus were isolated from fecal samples of healthy young people in Tibet, Xinjiang, and Inner Mongolia using pure culture methods. Lactobacillus ruminis and Lactobacillus gasseri were the dominant Lactobacillus species isolated from the intestinal microflora, accounting for 54.4% and 14.0% of the total isolates, respectively. Isolated strains were identified by 16S rRNA sequencing, and their tolerance to gastric acid and bile salt, and fermentation characteristics were evaluated. The results of experiments in vitro showed that nine of the isolated strains of Lactobacillus grew well at pH 3.0. After 11 h of incubation in artificial digestive juices, the isolated L. plantarum and the control strain L. plantarum P8 still had high survival rates. Most of the isolates and control isolates have strong tolerance to bile salts. The evaluation of fermentation characteristics indicated that the ability of the intestinal Lactobacillus to ferment skimmed milk was lower than that of the reference L. plantarum P8. In the process of storage, the viable count of screened isolates of human origin in fermented milk decreased to some extent, but remained above 7.01 ± 0.22 log CFU/ml, showing good storage characteristics.

Revealing the effect of lipopeptide on improving the probiotics characteristics: Flavor and texture enhancer in the formulated yogurt

Probiotics are beneficial viable microorganisms that protects from pathogens, enhance immunity and health. In this study, a biosurfactant from marine sponge associated bacteria MS48 was used to effectively enhance the survival of starter cultures and thereby improving their functional properties. The biosurfactant MS48 was characterized as lipopeptide based upon the spectroscopic analysis. The GC-MS analysis showed the moiety as l-glutamic acid methyl ester with the mass of m/z 161.16. Probiotics supplemented with lipopeptide showed better survival in the stress tolerance assays includes acid, bile, heat, salt stress and other assays including auto-aggregation, hydrophobicity, microbial adhesion to solvents (MATS), and simulated gastric juice. Yogurt formulated using lipopeptide showed enhanced flavor components, stability, improved characteristics, EPS production, and lower syneresis than the control. Malonic acid, acidity regulator was detected in the mass spectrum of lipopeptide added yogurt. The texture analysis of the lipopeptide added yogurt showed improved textural and sensorial properties when compared to the control.

In vitro gastrointestinal resistance of Lactobacillus acidophilus in some dairy products

In this study, different dairy products such as ice cream, yoghurt, white pickled cheese, and fermented acidophilus milk were manufactured by using either Lactobacillus acidophilus DSM 20,079 or Lactobacillus acidophilus NCFM. The counts of L. acidophilus in the samples on days 1, 15, and 30 of the storage were determined. Additionally, the samples contained L. acidophilus were passed through a dynamic gastrointestinal model designed in laboratory conditions to compare the protective effect of different dairy products on viability of L. acidophilus against stress factors of the gastrointestinal model. The counts of L. acidophilus NCFM and L. acidophilus DSM 20,079 in the samples decreased by between 0.04 and 0.37 log units and by between 0.11 and 0.27 log units, respectively, within 30 days of storage. During the passage through the gastrointestinal model, the highest percentage reduction in the counts of L. acidophilus was determined in yoghurt followed by fermented acidophilus milk, white pickled cheese, and ice cream, respectively. The reduction in the counts of L. acidophilus in the samples during the passage through the model increased with extension of storage time. The results of this study showed that the reduction in the counts L. acidophilus in the samples during the passage through the model was influenced significantly by the matrix of the dairy product and storage period.

Probiotic Characterization of Cholesterol-Lowering Lactobacillus fermentum MJM60397

Lactobacillus fermentum MJM60397 was subjected to in vitro safety tests and in vivo probiotic characterization. The MJM60397 strain was susceptible to antibiotics and was found to be non-mucinolytic and non-hemolytic, and does not produce bioamines. In addition, MJM60397 tolerated simulated oro-gastrointestinal conditions and adhered to Caco-2 cells. MJM60397 also exhibited bile salt hydrolase activity and could deconjugate bile acids. The hypocholesterolemic effects of strain MJM60397 were studied in high-fat diet-induced hypercholesterolemic male ICR mice. The mice were fed a high-cholesterol diet (HCD) and were divided into the following three experimental groups: HCD-control (HCD-Con), mice fed with HCD + L. fermentum MJM60397 (HCD-MJM60397), and mice fed with HCD + L. acidophilus ATCC 43121 (HCD-L.ac) as the positive control. Simultaneously, a normal control diet (NCD) group was maintained. After 7 weeks, the total cholesterol and low-density lipoprotein (LDL) cholesterol levels were significantly reduced in the livers of the HCD-MJM60397 mice when compared to those in the HCD-Con and HCD-L.ac mice. Fecal total bile acid content was significantly (P < 0.05) higher in the HCD-MJM60397 group than in the NCD, HCD-Con, and HCD-L.ac groups. Analysis of gene expression revealed higher expression of LDLR gene in the livers of the HCD-MJM60397 and HCD-L.ac mice than in the livers of the HCD-Con mice. These findings show that the hypocholesterolemic effects of the MJM60397 strain were attributable to its bile salt deconjugating activity, which resulted in decreased bile acid absorption and increased excretion of bile acids in the feces. These results indicate that L. fermentum MJM60397 could be developed into a potential probiotic for reducing the serum cholesterol levels.

Compatibility, Cytotoxicity, and Gastrointestinal Tenacity of Bacteriocin-Producing Bacteria Selected for a Consortium Probiotic Formulation to Be Used in Livestock Feed

Bacteriocin-producing Escherichia coli ICVB442, E. coli ICVB443, Enterococcus faecalis ICVB497, E. faecalis ICVB501, and Pediococcus pentosaceus ICVB491 strains were examined for their pathogenic risks and compatibility and hence suitability as consortium probiotic bacteria. Except for E. coli ICVB442, all were inclined to form biofilm. All were gelatinase-negative, sensitive to most of the antibiotics tested and not cytotoxic to porcine intestinal epithelial cells (IPEC-1) when tested at a multiplicity of infection (MOI) of 1. P. pentosaceus ICVB491 stood apart by inhibiting the other four strains. Both E. coli strains and E. faecalis ICVB497 strain were β-hemolytic. Survival in the TIM-1 dynamic model of the human digestive system was 139% for the tested E. coli ICVB443 strain, 46% for P. pentosaceus ICVB491, and 32% for the preferred E. faecalis ICVB501 strain. These three potential probiotics, which are bacteriocin-producing strains, will be considered for simultaneous use as consortium with synergistic interactions in vivo on animal model.

Impact of oral galenic formulations of Lactobacillus salivarius on probiotic survival and interactions with microbiota in human in vitro gut models

Health benefits of probiotics in humans essentially depend on their ability to survive during gastrointestinal (GI) transit and to modulate gut microbiota. To date, there is few data on the impact of galenic formulations of probiotics on these parameters. Even if clinical studies remain the gold standard to evaluate the efficacy of galenic forms, they stay hampered by technical, ethical and cost reasons. As an alternative approach, we used two complementary in vitro models of the human gut, the TNO gastrointestinal (TIM-1) model and the Artificial Colon (ARCOL), to study the effect of three oral formulations of a Lactobacillus salivarius strain (powder, capsule and sustained-release tablet) on its viability and interactions with gut microbiota. In the TIM-1 stomach, no or low numbers of bacteria were respectively released from the capsule and tablet, confirming their gastro-resistance. The capsule was disintegrated in the jejunum on average 76 min after administration while the core of sustained-release tablet was still intact at the end of digestion. Viability in TIM-1 was significantly influenced by the galenic form with survival percentages of 0.003±0.004%, 2.8±0.6% and 17.0±1.8% (n=3) for powder, capsule and tablet, respectively. In the ARCOL, the survival of the strain tended to be higher in the post-treatment phase with the tablet compared to capsule, but gut microbiota composition and activity were not differently modulated by the two formulations. In conclusion, the sustained-release tablet emerged as the formulation that most effectively preserved viability of the tested strain during GI passage. This study highlights the usefulness of in vitro gut models for the pre-screening of probiotic pharmaceutical forms. Their use could also easily be extended to the evaluation of the effects of food matrices and age on probiotic survival and activity during GI transit.

Replacement of Metaphylactic Antimicrobial Therapy by Oral Administration of Ligilactobacillus salivarius MP100 in a Pig Farm

Antibiotic use in swine production contributes to the emergence and spread of resistant bacteria, which poses a threat on human health. Therefore, alternative approaches must be developed. The objective of this work was the characterization of the probiotic properties of a Ligilactobacillus salivarius strain isolated from sow's milk and its application as an inoculated fermented feed to pregnant sows and piglets. The study was carried in a farm in which metaphylactic use of antimicrobials (including zinc oxide) was eliminated at the time of starting the probiotic intervention, which lasted for 2 years. Feces from 8-week-old piglets were collected before and after the treatment and microbiological and biochemical analyses were performed. The procedure led to an increase in the concentrations of clostridia and lactobacilli-related bacteria. Parallel, an increase in the concentration of butyrate, propionate and acetate was observed and a notable reduction in the presence of antibiotic resistant lactobacilli became apparent. In conclusion, replacement of antimicrobials by a microbiota-friendly approach was feasible and led to positive microbiological and biochemical changes in the enteric environment.

Suppressive effects of Streptococcus thermophilus KLDS 3.1003 on some foodborne pathogens revealed through in vitro, in vivo and genomic insights

Foodborne diseases (FBDs) remain a persistent global challenge and recent research efforts suggest that lactic acid bacteria (LAB) strains can contribute towards their prevention and treatment. This study investigates the genetic properties of Streptococcus thermophilus KLDS 3.1003 as a potential probiotic and health-promoting LAB strain as well as its in vitro and in vivo activities against two foodborne pathogens. In vitro, its antimicrobial activities and tolerance levels in simulated bile salts and acids were determined. The cytotoxic effects of the LAB strain in RAW264.7 cells were also evaluated. For in vivo evaluation, 24 BALB/c mice were orally administered control and trial diets for 14 days. Genomic analyses of this strain's bacteriocin configuration, stress response system and multidrug resistance genes were annotated to validate in vitro and in vivo results. In vitro antimicrobial results show that the cells and CFS of S. thermophilus KLDS 3.1003 could inhibit both pathogens with the former being more effective (P < 0.05). In addition, its cell-free supernatant (CFS) could inhibit the growth of both pathogens, with catalase treatment having the highest effect against it. More so, after 3 h of incubation, survivability levels of S. thermophilus KLDS 3.1003 were significantly high (P < 0.05). LPS-induced RAW264.7 cell activities were also significantly reduced by 108-109 CFU mL-1 of S. thermophilus KLDS. In vivo, significant weight losses were inhibited in the TSTEC group compared to the TSTSA group (P < 0.05). Moreover, pathogen-disrupted blood biochemical parameters like HDL, LDL, TP, TG, AST, ALT and some minerals were restored in the respective prevention groups (TSTEC and TSTSA). Genomic analyses showed that S. thermophilus KLDS 3.1003 has bacteriocin-coding peptides, which accounts for its antimicrobial abilities in vitro and in vivo. S. thermophilus KLDS 3.1003 is also endowed with intact genes for acid tolerance, salt-resistance, cold and heat shock responses and antioxidant activities, which are required to promote activities against the selected foodborne pathogens. This study showed that S. thermophilus KLDS 3.1003 has the genomic capacity to inhibit foodborne pathogens' growth in vitro and in vivo, thus qualifying it as a potential probiotic, antimicrobial and bio-therapeutic candidate.

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.

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.

Mechanisms of absorption of vitamin D3 delivered in protein nanoparticles in the absence and presence of fat

Novel protein-based nanovehicles offer alternatives to fat for delivery of lipophilic bioactives (nutraceuticals and drugs), yet they raise important questions regarding the bioavailability and absorption mechanism of the bioactive without fat. To provide answers, we chose vitamin D₃ (VD₃) as a model lipophilic-nutraceutical, re-assembled casein-micelles (rCM) as model protein-based nanovehicles, and non-fat yoghurt as a model food. We prepared three yoghurt formulations: 3% fat with VD₃ dissolved in milk-fat, non-fat and 3% fat, both latter enriched with VD₃ within rCM. Following in vitro digestion, VD₃ retention and bioaccessibility were high (∼90% and ∼70%, respectively) in all formulations. VD₃ uptake by Caco-2 cells was three-fold higher (p < 0.005) in the non-fat yoghurt enriched with VD₃ in rCM compared with enriched fat-containing yoghurts. SR-BI, CD36 and NPC1L1 transporters were involved in VD₃ absorption irrespective of the composition. Thus, our findings demonstrate that protein nanovehicles may improve VD₃ bioavailability, without altering its absorption mechanism compared to that from fat.

Influence of guabiroba pulp (campomanesia xanthocarpa o. berg) added to fermented milk on probiotic survival under in vitro simulated gastrointestinal conditions

In fermented milks inoculated with two thermophilic strains (Lactobacillus bulgaricus and Streptococcus thermophilus), guabiroba pulp (Campomanesia xanthocarpa O. Berg) was added in different concentrations: 5% (I5 sample) and 10% (I10 sample), compared to a control sample, with no pulp addition. In these fermented milks, Bifidobacterium BB-12 was added and the samples were submitted to a progressive gastrointestinal simulation in vitro. The cells count was performed, including the survival rates for all the progressive steps of the simulated digestion. Total phenolic content (TPC) and antioxidant activity analysis by FRAP (Ferric Reducing Antioxidant Power) and DPPH (2,2-diphenyl-1-picrylhydrazyl) were performed in all the gastrointestinal steps. Before and during the entire gastrointestinal tract, the Bifidobacterium BB-12 count was 8-9 log CFU g^-1, above the recommended for a probiotic product, with a highlight in intestinal colon steps. The I10 sample showed the highest viable cell count, the highest total phenolic content and antioxidant activity throughout the entire gastric steps (p < 0.05). The fermented milk proved to be an effective matrix for the probiotic stability and incorporation of guabiroba components. Bioactive compounds present in the guabiroba pulp may have occasioned a prebiotic and protective effect on Bifidobacterium BB-12 after gastric conditions. The possible bioconversion of these compounds in more active forms can contribute to the absorption in epithelial cells, enhancing fermented milks with guabiroba pulp as important sources of dietary accessible bioactive compounds.

Impact of bile salts and a medium chain fatty acid on the physical properties of self-emulsifying drug delivery systems

The aim of this study was the evaluation of the influence of bile salts and fatty acids, important components of intestinal fluids, on physical characteristics of self-emulsifying drug delivery systems (SEDDS) such as size, polydispersity (PDI), zeta potential (Zp), turbidity (T%), cloud point temperature (CPT) and drug release. At this purpose, nonionic (ni-SEDDS) and cationic (c-SEDDS) were emulsified in aqueous media containing increasing concentrations of bile salts (BS) and decanoate (Dec). Zp of ni-SEDDS and c-SEDDS became highly negative at 15 mM BS and Dec. Size of ni-SEDDS decreased of 112 nm and of 76 nm at 15 mM BS and Dec, respectively. Size of c-SEDDS decreased of 53 nm at 15 mM BS, but it was not affected by 15 mM Dec. PDI and T% of ni- and c-SEDDS were lowered as well. CPT of ni-SEDDS increased from 70 °C to 97 °C and 84 °C at 15 mM BS and Dec. CPT of c-SEDDS decreased from above 100 °C to 80 °C and to 85 °C at 1.5 mM BS and at 5 mM Dec, respectively. Generally, BS had a more pronounced effect on SEDDS Zp, size, PDI, T %, and CPT than Dec. The release of the model drug quinine was accelerated by BS and Dec. As BS and fatty acids affect the physical characteristics and drug release behavior of SEDDS, their impact should be addressed during the development process.

Probiotic Lactobacillus rhamnosus Supplementation Improved Capecitabine Protective Effect against Gastric Cancer Growth in Male BALB/c Mice

The gastric cancer (GC) is biologically and genetically heterogeneous with a poorly understood carcinogenesis at the molecular level. Herein, we studied the effects of probiotics (Lactobacillus rhamnosus) on subcutaneous implantation of xenograft GC. Moreover, the effect of probiotics (L. rhamnosus) was compared with the capecitabine drug as known used drug against GC. Human GC tissue was obtained from patients with gastric adenocarcinoma and grafted into mice armpit. Probiotic (L. rhamnosus) was given to animals by gavage 2 weeks prior to GC and 4 weeks after GC induction. Also, capecitabine was orally added through feeding tube at the last week of treatment procedure. All grafted animals received cyclosporine a day before the surgery and during the study period to prevent graft rejection. Capecitabine-probiotic complex reduced the size of the axillary implanted GC when compared with control group. Furthermore, combination of capecitabine and probiotic increased apoptotic and necrotic responses in the grafted tumor, blood cells (red blood cells, white blood cells, and platelet counts) in comparison with capecitabine. Probiotic (L. rhamnosus) administration effectively improved the therapeutic index and outcomes, and also, improved the therapeutic effects of the capecitabine.

Isolation and characterization of lactic acid bacteria from human milk

Human milk is the main source of nutrition for infants and the transmission of various microorganisms. The lactic acid bacteria (LAB) in breast milk allow for the establishment of the gut microflora of infants. In this study, we aimed to assess the probiotic potential of LAB strains isolated from breast milk of healthy Chinese women. Two strains, Lacticaseibacillus rhamnosus (formerly Lactobacillus rhamnosus) LHL6 and LHL7, were selected and identified through morphology observation, Gram staining, and 16S rDNA phylogenetic analysis. Using Limosilactobacillus fermentum (formerly Lactobacillus fermentum) CECT5716 as the standard reference strain, the screened strains were characterized for aspects of growth, production of lactic acid and H₂O₂, antibiotic susceptibility, survival under simulated gastrointestinal conditions, and tolerance to cadmium (Cd). In de Man, Rogosa, and Sharpe (MRS) broth, LHL6 and LHL7 showed longer lag phases than CECT5716 but higher specific growth rates. For the production of lactic acid and H₂O₂, LHL7 performed better than LHL6 and CECT5716, indicating better antimicrobial ability. Strain LHL7 generated 9.99 mg/L H₂O₂, considerably higher than 1.25 mg/L for LHL6 and 2.33 mg/L for CECT5716. According to European Food Safety Authority minimum inhibitory concentrations, all of the investigated strains were resistant to chloramphenicol, streptomycin, and kanamycin. However, unlike LHL6 and CECT5716, LHL7 was susceptible to ampicillin and resistant to tetracycline. Resistance to azithromycin, cephalexin, and penicillin G were similar for all 3 strains, whereas CECT5716 was resistant to a higher concentration of roxithromycin. All 3 strains were able to survive in a simulated gastric-like solution, but a low percentage survived in the presence of 0.4% bile salt and 7% pancreatin. Encapsulation with protectants may enhance the survival rate. All 3 strains were tolerant to 500 mg/L Cd in MRS broth and to 1,000 mg/L Cd on MRS agar medium. In summary, 2 novel strains of LAB were obtained that have similar characteristics to the reference strain CECT5716. This work identified potential probiotic candidates for application in the food and pharmaceutical industries and facilitated identification of further probiotics.

Characterization of Lactic Acid Bacteria in Raw Buffalo Milk: a Screening for Novel Probiotic Candidates and Their Transcriptional Response to Acid Stress

Lactic acid bacteria (LAB) are important microorganisms for the food industry due to their functional activity, as starters and potential probiotic strains. With that in mind, we explored the LAB diversity in raw buffalo milk, screening for novel potential probiotic strains. A total of 11 strains were identified by combination of MALDI-TOF and partial 16S rDNA sequencing and selected as potential probiotic candidates. Bacteria innocuity assessment was performed by determining antimicrobial susceptibility and the presence of virulence factors. Antagonism activity against Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes and Staphylococcus aureus was assessed, as well as milk proteolytic activity and exopolysaccharides production. Seven strains were identified as innocuous and two of them, Lactobacillus rhamnosus LB1.5 and Lactobacillus paracasei LB6.4 were selected for further probiotic potential analyses. Both strains demonstrated adhesion ability to Caco-2 cells, coaggregated with S. aureus and E. coli and maintained cell viability after gastrointestinal simulation in vitro, suggesting their probiotic potential. Furthermore, the transcriptional response of Lact. rhamnosus LB1.5 and Lact. paracasei LB6.4 to in vitro acid stress was assessed by RT-qPCR targeting seven genes related to adhesion, aggregation, stress tolerance, DNA repair and central metabolism. The association between the transcriptional responses and the maintenance of cell viability after gastrointestinal simulation highlights the genetic ability as probiotic of the two selected strains. Finally, we have concluded that Lact. rhamnosus LB1.5 and Lact. paracasei LB6.4 are important probiotic candidates to further in vivo studies.

Beneficial bile acid metabolism from Lactobacillus plantarum of food origin

Bile acid (BA) signatures are altered in many disease states. BA metabolism is an important microbial function to assist gut colonization and persistence, as well as microbial survival during gastro intestinal (GI) transit and it is an important criteria for potential probiotic bacteria. Microbes that express bile salt hydrolase (BSH), gateway BA modifying enzymes, are considered to have an advantage in the gut. This property is reported as selectively limited to gut-associated microbes. Food-associated microbes have the potential to confer health benefits to the human consumer. Here, we report that food associated Lactobacillus plantarum strains are capable of BA metabolism, they can withstand BA associated stress and propagate, a recognised important characteristic for GIT survival. Furthermore, we report that these food associated Lactobacillus plantarum strains have the selective ability to alter BA signatures in favour of receptor activation that would be beneficial to humans. Indeed, all of the strains examined showed a clear preference to alter human glycol-conjugated BAs, although clear strain-dependent modifications were also evident. This study demonstrates that BA metabolism by food-borne non-pathogenic bacteria is beneficial to both microbe and man and it identifies an evolutionary-conserved characteristic, previously considered unique to gut residents, among food-associated non-pathogenic isolates.

Application of the dynamic gastrointestinal simulator (simgi®) to assess the impact of probiotic supplementation in the metabolism of grape polyphenols

In this paper, the Dynamic Gastrointestinal Simulator (simgi®) is used as a model to the study the metabolic activity of probiotics at the intestinal level, and in particular, to assess the impact of probiotic supplementation in the microbial metabolism of grape polyphenols. Two independent simulations using fecal samples from two healthy volunteers were carried out. Changes in microbiota composition and in metabolic activity were assessed by qPCR and 16S rRNA gene sequencing and by analyses of phenolic metabolites and ammonium ions (NH₄⁺). The strain Lactobacillus plantarum CLC 17 was successfully implanted in the colon compartments of the simgi® after daily feeding of 2 × 10¹⁰ CFU/day for 7 days. Overall, no changes in bacterial diversity were observed after probiotic implantation. In comparison to the digestion of the grape polyphenols on their own, the inclusion of L. plantarum CLC 17 in the simgi® colon compartments led to a greater formation of phenolic metabolites such as benzoic acids, probably by the breakdown of high-molecular-weight procyanidin polymers. These results provide evidence that the probiotic strain Lactobacillus plantarum CLC 17 may improve the metabolism of dietary polyphenols when used as a food ingredient.

Partial rpoB Gene Sequencing Identification and Probiotic Potential of Floricoccus penangensis ML061-4 Isolated from Assam Tea (Camellia sinensis var. assamica)

Assam tea or Miang is a local name of Camellia sinensis var. assamica in northern Thailand. By the local wisdom, Assam tea leaves are used as the raw material in tea fermentation to produce “Fermented Miang” consumed by people in northern Thailand and the countries nearby. In this study, twenty-eight bacterial isolates were obtained from Assam tea leaf samples collected from Nan province, Thailand. Bacterial isolates were identified within 6 genera including Bacillus, Floricoccus, Kocuria, Lysinibacillus, Micrococcus and Staphylococcus. Among these, the strain ML061-4 shared 100.0 and 99.4% similarity of 16S rRNA and rpoB gene sequence with F. penangensis JCM 31735^T, respectively. This is the first discovery of F. penangensis in Thailand. F. penangensis ML061-4 exhibited probiotic characteristics including lactic acid production (9.19 ± 0.10 mg/ml), antibacterial activities (Escherichia coli ATCC 25922 and E. coli O157:H7 DMST 12743), acid and bile salt tolerance (71.1 and 54.9%, respectively), autoaggregation (97.0%), coaggregation (66.0% with E. coli O157:H7), cell surface hydrophobicity (90.0%), bacterial adhesion (82.9% with Lactobacillus plantarum FM03-1), competitive inhibition (17.8% with E. coli O157:H7) and competitive exclusion (34.9% with E. coli O157:H7). Overall, the data suggested that F. penangensis ML061-4 had a great potential to be a probiotic.

Probiotic survival during a multi-layered tablet development as tested in a dynamic, computer-controlled in vitro model of the stomach and small intestine (TIM-1)

The aim of the research was to develop a galenical formulation for the combination of the three probiotic strains Lactobacillus gasseri PA 16/8, Bifidobacterium longum SP 07/3 and Bifidobacterium bifidum MF 20/5 that would lead to the presence of a high amount of viable cells in the small intestine, the presumed site of action of these strains. This was tested in a validated, dynamic in vitro model of the stomach and small intestine (TIM‐1), simulating human adults after intake of a meal. Experiments were performed both in the gastric compartment of the model, as well as in the complete system (stomach + small intestine). Survival of the strains in an unformulated probiotic powder after transit through the gastric compartment was 5·3% for the bifidobacteria and 1% for L. gasseri. After transit through the complete gastrointestinal tract, this dropped to 2% for bifidobacteria and 0·1% for Lactobacillus. After several rounds of optimization, an enteric‐coated tablet was developed that increased the delivery of viable cells reaching the small intestine to 72% (gastric survival) for bifidobacteria, and 53% (gastric) for L. gasseri. Also survival in the small intestine increased by about an order of magnitude. The final galenical formulation was tested in two applications: adults and elderly, both of which have their own physiological parameters. These experiments corroborated the results obtained in the development phase of the project. In conclusion, the developed enteric coating led to a 20‐ to 40‐fold increase in the delivery of viable cells to the small intestine.

Significance and Impact of the Study

Predictive GI in vitro models are very helpful and reliable tools for the development of new galenical formula containing probiotics, and in the current example helped to deliver >10‐fold higher numbers of viable cells to the small intestine, presumably leading to improved functionality of the strains.

Survival of Kluyveromyces lactis and Torulaspora delbrueckii to simulated gastrointestinal conditions and their use as single and mixed inoculum for cheese production

The demand for new probiotic products has shown recent increases alongside a growing interest in studying starter cultures of cheeses. This study thus aims to evaluate the ability to survive under simulated gastrointestinal conditions and impact of Torulaspora delbrueckii B14 and Kluyveromyces lactis B10 as single and mixed inocula for cheese production. These two yeast strains were subjected to simulated gastrointestinal tracts and tested for self-aggregation, hydrophobicity, pathogen inhibition, antibiotic resistance, and β-galactosidase production. The yeast strains were also assessed for their ability to survive in different NaCl concentrations (2.5%, 5%, and 10% w/v), multiple temperatures (4 °C and 40 °C), and used as single and mixed starter cultures for cheese production. Yeasts population levels were monitored by YPD plating and MALDI-TOF and metabolites were analyzed by HPLC and GC-MS over the course of the 21 days cheese maturation process. T. delbrueckii B14 and K. lactis B10 both showed >80% viability after the passage through the simulated gastrointestinal tract, had self-aggregation rates >90%, and displayed β-galactosidase activities of 0.35 U/g and 0.53 U/g, respectively. Both yeasts survived at 2.5%, 5%, and 10% NaCl for 21 days and showed growth at 4 °C. In cheese, the single inoculum of K. lactis B10 and mixed inoculum showed the highest levels of lactose consumption. HS-SPME GC-MS analysis of cheese samples allowed the identification of 38 volatile compounds. The highest concentrations of most of these compounds were observed after 21 days of maturation for the cheese produced with mixed inoculum. The most abundant acids detected were hexanoic and decanoic acid; the most abundant alcohols were 2,3-butanediol, 2-phenylethanol and isoamyl alcohol, and the most prevalent ester compounds were isoamyl acetate and phenethyl acetate. Our results therefore show that T. delbrueckii B14 and K. lactis B10 are interesting yeasts for further studies in the context of probiotics and positively impact the composition of desirable volatile compounds in cheeses, particularly when used as mixed inoculum.

Potential effect of probiotics in the treatment of breast cancer

Breast cancer is one of the most important causes of cancerrelated morbidity and mortality in the world. Probiotics, as functional food, have the potential to act against breast cancer, as evidenced by cell-based and animal model experiments. Probiotic may be useful in prevention or treatment of breast cancer by modulating the gastrointestinal bacteria and the systemic immune system. However, large-scale clinical trials and intensive research are mandatory to confirm the in vitro and in vivo results and exploring the probiotics-related metabolic, immune, and molecular mechanisms in breast cancer. This current review summarizes the available data related to probiotics and their potential role in the treatment of breast cancer.