Study of the Ability of Bifidobacteria of Human Origin to Prevent and Treat Rotavirus Infection Using Colonic Cell and Mouse Models

Probiotics and Prebiotics Intervention in Respiratory and Digestive Infections Linked to Covid-19

Probiotics and prebiotics have been suggested as natural agents against viral infections and dysbiosis and may encourage clinical applications. This review aims to analyze the main and recent advances related to viral infections such as Covid-19 and its gastrointestinal complications, antiviral immunity generated and possible preventive role that probiotics and/or prebiotics can play in controlling and promoting antiviral immunity. The literature search was performed through a critical analysis of relevant publications reported in PubMed and Scopus databases on clinical trials and assays conducted in vitro on colon cells and in vivo on mice. Some studies using probiotics and prebiotics for the prevention of viral infection in different age groups are discussed. Covid-19 patients have been shown to suffer from gastrointestinal complications in addition to respiratory symptoms due to interactions between the respiratory system and the gastrointestinal tract infected with SARS-CoV-2. Unfortunately, therapies used to prevent (or treat) symptoms of Covid-19 have proven to be of limited effectiveness. In addition, the lack of access to coronavirus vaccines around the world and vaccine hesitancy continue to hamper control of Covid-19. It is therefore crucial to find alternative methods that can prevent disease symptoms. Evidence-based efficacy of certain probiotics (Lactobacillus and Bifidobacterium) that may be useful in viral infections was shown with immunomodulatory properties (pro-inflammatory mediators reduction), promoting antiviral immunity (antibodies production, virus titers) and controlling inflammation (anti-inflammatory effect), as well as viral clearance and antimicrobial potential against opportunistic bacteria (anti-dysbiosis effect). But, available data about clinical application of probiotics in Covid-19 context remain limited and relevant scientific investigation is still in its early stages. Also, evidence for prebiotics potential in this field is limited, since the exact mechanism involved in systemic immune modulation by these compounds is till now unknown. Thus, further research is necessary to explore in the viral infection context the mechanism by which gut and lung interact in the presence of probiotics and prebiotics through more animal and clinical experiments.

Recent insights and advances in gut microbiota's influence on host antiviral immunity

A diverse array of microbial organisms colonizes the human body, collectively known as symbiotic microbial communities. Among the various pathogen infections that hosts encounter, viral infections represent one of the most significant public health challenges worldwide. The gut microbiota is considered an important biological barrier against viral infections and may serve as a promising target for adjuvant antiviral therapy. However, the potential impact of symbiotic microbiota on viral infection remains relatively understudied. In this review, we discuss the specific regulatory mechanisms of gut microbiota in antiviral immunity, highlighting recent advances in how gut microbiota regulate the host immune response, produce immune-related molecules, and enhance the host's defense against viruses. Finally, we also discuss the antiviral potential of oral probiotics.

The protective role of prebiotics and probiotics on diarrhea and gut damage in the rotavirus-infected piglets

Rotavirus is one of the pathogenic causes that induce diarrhea in young animals, especially piglets, worldwide. However, nowadays, there is no specific drug available to treat the disease, and the related vaccines have no obvious efficiency in some countries. Via analyzing the pathogenesis of rotavirus, it inducing diarrhea is mainly due to disturb enteric nervous system, destroy gut mucosal integrity, induce intracellular electrolyte imbalance, and impair gut microbiota and immunity. Many studies have already proved that prebiotics and probiotics can mitigate the damage and diarrhea induced by rotavirus infection in hosts. Based on these, the current review summarizes and discusses the effects and mechanisms of prebiotics and probiotics on rotavirus-induced diarrhea in piglets. This information will highlight the basis for the swine production utilization of prebiotics and probiotics in the prevention or treatment of rotavirus infection in the future.

Microbiota-Derived Extracellular Vesicles as a Postbiotic Strategy to Alleviate Diarrhea and Enhance Immunity in Rotavirus-Infected Neonatal Rats

Rotavirus (RV) infection is a major cause of acute gastroenteritis in children under 5 years old, resulting in elevated mortality rates in low-income countries. The efficacy of anti-RV vaccines is limited in underdeveloped countries, emphasizing the need for novel strategies to boost immunity and alleviate RV-induced diarrhea. This study explores the effectiveness of interventions involving extracellular vesicles (EVs) from probiotic and commensal E. coli in mitigating diarrhea and enhancing immunity in a preclinical model of RV infection in suckling rats. On days 8 and 16 of life, variables related to humoral and cellular immunity and intestinal function/architecture were assessed. Both interventions enhanced humoral (serum immunoglobulins) and cellular (splenic natural killer (NK), cytotoxic T (Tc) and positive T-cell receptor γδ (TCRγδ) cells) immunity against viral infections and downregulated the intestinal serotonin receptor-3 (HTR3). However, certain effects were strain-specific. EcoR12 EVs activated intestinal CD68, TLR2 and IL-12 expression, whereas EcN EVs improved intestinal maturation, barrier properties (goblet cell numbers/mucin 2 expression) and absorptive function (villus length). In conclusion, interventions involving probiotic/microbiota EVs may serve as a safe postbiotic strategy to improve clinical symptoms and immune responses during RV infection in the neonatal period. Furthermore, they could be used as adjuvants to enhance the immunogenicity and efficacy of anti-RV vaccines.

Postbiotic Activities of Bifidobacterium adolescentis: Impacts on Viability, Structural Integrity, and Cell Death Markers in Human Intestinal C2BBe1 Cells

Acute diarrheal disease (ADD) caused by rotavirus (RV) contributes significantly to morbidity and mortality in children under five years of age. Currently, there are no specific drugs for the treatment of RV infections. Previously, we reported the anti-rotaviral activity of the protein metabolites derived from Bifidobacterium adolescentis. In this study, our aim was to assess the impact of B. adolescentis-secreted proteins (BaSP), with anti-rotaviral activity on the human intestinal C2BBe1 cell line. We initiated the production of BaSP and subsequently confirmed its anti-rotaviral activity by counting the infectious foci using immunocytochemistry. We then exposed the C2BBe1 cells to various concentrations of BaSP (≤250 µg/mL) for 72 h. Cell viability was assessed using the MTT assay, cell monolayer integrity was monitored through transepithelial electrical resistance (TEER), and cytoskeleton architecture and tight junctions (TJs) were examined using confocal microscopy with F-actin and occludin staining. Finally, we utilized a commercial kit to detect markers of apoptosis and necrosis after 24 h of treatment. The results demonstrated that BaSP does not have adverse effects on C2BBe1 cells. These findings confirm that BaSP inhibits rotavirus infectivity and has the potential to strengthen intestinal defense against viral and bacterial infections via the paracellular route.

Dietary intervention with functional foods modulating gut microbiota for improving the efficacy of COVID-19 vaccines

Dysbiosis of the gut microbiota with aging contributes to a reduction in important cross-feeding bacterial reactions in the gut and immunosenescence, which could contribute to a decrease in vaccine efficacy. Fever, cough, and fatigue are the main signs of coronavirus disease 2019 (COVID-19); however, some patients with COVID-19 present with gastrointestinal symptoms. COVID-19 vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the best measures to reduce SARS-CoV-2 infection rates and the severity of COVID-19. The immunogenicity of COVID-19 vaccines is influenced by the composition of the gut microbiota, and the immune response to COVID-19 vaccines decreases with age. In this review, we discuss gut microbiota dysbiosis and immunosenescence in the older adults, the role of gut microbiota in improving the efficacy of COVID-19 vaccines, and dietary interventions to improve the efficacy of COVID-19 vaccines in the older adults.

Advances in the development of antivirals for rotavirus infection

Rotavirus (RV) causes 200,000 deaths per year and imposes a serious burden to public health and livestock farming worldwide. Currently, rehydration (oral and intravenous) remains the main strategy for the treatment of rotavirus gastroenteritis (RVGE), and no specific drugs are available. This review discusses the viral replication cycle in detail and outlines possible therapeutic approaches including immunotherapy, probiotic-assisted therapy, anti-enteric secretory drugs, Chinese medicine, and natural compounds. We present the latest advances in the field of rotavirus antivirals and highlights the potential use of Chinese medicine and natural compounds as therapeutic agents. This review provides an important reference for rotavirus prevention and treatment.

In Vitro Evaluation of Brown Seaweed Laminaria spp. as a Source of Antibacterial and Prebiotic Extracts That Could Modulate the Gastrointestinal Microbiota of Weaned Pigs

Laminaria spp. and their extracts have preventative potential as dietary supplements during weaning in pigs. The first objective of this study was to evaluate increasing concentrations of four whole seaweed biomass samples from two different Laminaria species harvested in two different months in a weaned pig faecal batch fermentation assay. Particularly, February and November whole seaweed biomass samples of L. hyperborea (LHWB-F and LHWB-N) and L. digitata (LDWB-F and LDWB-N) were used. In the next part of the study, the increasing concentrations of four extracts produced from L. hyperborea (LHE1-4) and L. digitata (LDE1-4) were evaluated in individual pure-culture growth assays using a panel of beneficial and pathogenic bacterial strains (second objective). The LHE1-4 and LDE1-4 were obtained using different combinations of temperature, incubation time and volume of solvent within a hydrothermal-assisted extraction methodology (E1-4). In the batch fermentation assay, the L. hyperborea biomass samples, LHWB-F and LHWB-N, lowered Bifidobacterium spp. counts compared to the L. digitata biomass samples, LDWB-F and LDWB-N (p < 0.05). LHWB-F and LDWB-N reduced Enterobacteriaceae counts (p < 0.05). LHWB-F and LDWB-F were selected as the most and least promising sources of antibacterial extracts from which to produce LHE1-4 and LDE1-4. In the pure-culture growth assays, E1- and E4-produced extracts were predominantly associated with antibacterial and bifidogenic activities, respectively. LHE1 reduced both Salmonella Typhimurium and Enterotoxigenic Escherichia coli with LDE1 having a similar effect on both of these pathogenic strains, albeit to a lesser extent (p < 0.05). Both LHE1 and LDE1 reduced B. thermophilum counts (p < 0.05). LDE4 exhibited strong bifidogenic activity (p < 0.05), whereas LHE4 increased Bifidobacterium thermophilum and Lactiplantibacillus plantarum counts (p < 0.05). In conclusion, antibacterial and bifidogenic extracts of Laminaria spp. were identified in vitro with the potential to alleviate gastrointestinal dysbiosis in newly weaned pigs.

Anti-rotavirus Properties and Mechanisms of Selected Gram-Positive and Gram-Negative Probiotics on Polarized Human Colonic (HT-29) Cells

Probiotics have been investigated to improve the universal rotavirus (RV) vaccination as well as to ameliorate the RV infection. However, underlying mechanisms how probiotics mediate beneficial effects needs more investigation. Thus, in the present study, we used polarized HT-29 cells to assess the anti-RV properties of Gram-positive, (Lactobacillus acidophilus, Lacticaseibacillus rhamnosus GG, and Bifidobacterium subsp. Lactis Bb12) and Gram negative, (Escherichia coli Nissle 1917) probiotics and study their underlying mechanisms. Our results showed that pre-treatment of HT-29 cells for 4 h with probiotics, significantly reduced (p < 0.05) human RV replication and this effect was most pronounced for E. coli Nissle followed by L. acidophilus and L. rhamnosus GG. Strikingly, only pre-treatment with live bacteria or their supernatants demonstrated anti-RV properties. Except Gram negative E. coli Nissle, the Gram-positive probiotics tested did not bind to RV. Ingenuity pathway analysis of tight junction (TJ)- and innate immune-associated genes indicated that E. coli Nissle or E. coli Nissle + RV treatments improved cell-cell adhesion and cell contact, while L. acidophilus or L. acidophilus + RV treatments also activated cell-cell contact but inhibited cell movement functions. RV alone inhibited migration of cells event. Additionally, E. coli Nissle activated pathways such as the innate immune and inflammatory responses via production of TNF, while RV infection activated NK cells and inflammatory responses. In conclusion, E. coli Nissle's ability to bind RV, modulate expression of TJ events, innate immune and inflammatory responses, via specific upstream regulators may explain superior anti-RV properties of E. coli Nissle. Therefore, prophylactic use of E. coli Nissle might help to reduce the RV disease burden in infants in endemic areas.

Bifidobacterium: Host-Microbiome Interaction and Mechanism of Action in Preventing Common Gut-Microbiota-Associated Complications in Preterm Infants: A Narrative Review

The development and health of infants are intertwined with the protective and regulatory functions of different microorganisms in the gut known as the gut microbiota. Preterm infants born with an imbalanced gut microbiota are at substantial risk of several diseases including inflammatory intestinal diseases, necrotizing enterocolitis, late-onset sepsis, neurodevelopmental disorders, and allergies which can potentially persist throughout adulthood. In this review, we have evaluated the role of Bifidobacterium as commonly used probiotics in the development of gut microbiota and prevention of common diseases in preterm infants which is not fully understood yet. The application of Bifidobacterium as a therapeutical approach in the re-programming of the gut microbiota in preterm infants, the mechanisms of host-microbiome interaction, and the mechanism of action of this bacterium have also been investigated, aiming to provide new insights and opportunities in microbiome-targeted interventions in personalized medicine.

Evaluation of the Antibacterial and Prebiotic Potential of Ascophyllum nodosum and Its Extracts Using Selected Bacterial Members of the Pig Gastrointestinal Microbiota

Ascophyllum nodosum and its extracts are promising antibacterial and prebiotic dietary supplements for pigs. The objectives of this study were to evaluate the effects of the increasing concentrations of: (1) two whole biomass samples of A. nodosum with different harvest seasons, February (ANWB-F) and November (ANWB-N), in a weaned pig faecal batch fermentation assay, and (2) A. nodosum extracts produced using four different extraction conditions of a hydrothermal-assisted extraction methodology (ANE1-4) and conventional extraction methods with water (ANWE) and ethanol (ANEE) as solvent in individual pure culture growth assays using a panel of beneficial and pathogenic bacterial strains. In the batch fermentation assay, ANWB-F reduced Bifidobacterium spp. counts (p < 0.05) while ANWB-N increased total bacterial counts and reduced Bifidobacterium spp. and Enterobacteriaceae counts (p < 0.05). Of the ANE1-4, produced from ANWB-F, ANWE and ANEE that were evaluated in the pure culture growth assays, the most interesting extracts were the ANE1 that reduced Salmonella Typhimurium, enterotoxigenic Escherichia coli and B. thermophilum counts and the ANE4 that stimulated B. thermophilum growth (p < 0.05). In conclusion, the extraction method and conditions influenced the bioactivities of the A. nodosum extracts with ANE1 and ANE4 exhibiting distinct antibacterial and prebiotic properties in vitro, respectively, that merit further exploration.

Establishment of a rotavirus-infected zebrafish model and its application in drug screening

Rotavirus (RV) is one of the main pathogens that induce infantile diarrhea and by now no effective drugs are available for RV-induced infantile diarrhea. Thus the development of novel models is of vital importance for the pathological research of RV-induced infantile diarrhea, as well as the progress of the associated treatment strategy. Here we introduced for the first time that RV-Wa strain and RV-SA-11 strain could infect 5 dpf(day post fertilization) and 28 dpf larvae, to induce infantile diarrhea model that was highly consistent with the clinical infection of infants. RV infection significantly changed the signs, survival rate and inflammation of larvae. Some important indicators, including the levels of RV antigen VP4 and VP6, the in vivo RV tracking, and the RV particles were also analyzed, which collectively demonstrated that the model was successfully established. More importantly, we also determined the potentials of the proposed RV-infected zebrafish model for anti-viral drug assessment. In conclusion, we established a RV-infected zebrafish model with formulated relevant indicators both larvae and adult fish, which might be served as a high throughput platform for antiviral drug screening.

KDP, a Lactobacilli Product from Kimchi, Enhances Mucosal Immunity by Increasing Secretory IgA in Mice and Exhibits Antimicrobial Activity

The potential of KDP, a lactic acid bacterial strain of Lactobacillus sakei, to enhance the production of mucosal specific immunoglobulin A (IgA) in mice and thereby enhance gut mucosal immunity was examined. KDP is composed of dead cells isolated from the Korean traditional food kimchi. Female BALB/c mice orally received 0.25 mg KDP once daily for 5 weeks and were co-administrated ovalbumin (OVA) for negative control and cholera toxin for positive control. Mice administered KDP exhibited increased secretory IgA (sIgA) contents in the small intestine, Peyer’s patches, serum, colon, and lungs as examined by ELISA. KDP also significantly increased the gene expression of Bcl-6, IL-10, IL-12p40, IL-21, and STAT4. In addition, KDP acted as a potent antioxidant, as indicated by its significant inhibitory effects in the range of 16.5–59.4% for DPPH, nitric oxide, maximum total antioxidant capacity, and maximum reducing power. Finally, KDP exhibited potent antimicrobial activity as evidenced by a significant decrease in the growth of 7 samples of gram-negative and gram-positive bacteria and Candida albicans. KDP’s adjuvant effect is shown to be comparable to that of cholera toxin. We conclude that KDP can significantly enhance the intestine’s secretory immunity to OVA, as well as act as a potent antioxidant and antimicrobial agent. These results suggest that orally administered KDP should be studied in clinical trials for antigen-specific IgA production.

Evaluation of the in vitro effects of the increasing inclusion levels of yeast β-glucan, a casein hydrolysate and its 5 kDa retentate on selected bacterial populations and strains commonly found in the gastrointestinal tract of pigs

Previously, the 5 kDa retentate (5kDaR) of a casein hydrolysate (CH) and yeast β-glucan (YBG) were identified as promising anti-inflammatory dietary supplements for supporting intestinal health in pigs post-weaning. However, their direct effects on intestinal bacterial populations are less well-known. The main objectives of this study were to determine if the increasing concentrations of the CH, 5kDaR and YBG individually, can: (1) alter the bacterial and short-chain fatty acid profiles in a weaned pig faecal batch fermentation assay, and (2) directly influence the growth of selected beneficial (Lactobacillus plantarum, L. reuteri, Bifidobacterium thermophilum) and pathogenic (Enterotoxigenic Escherichia coli, Salmonella Typhimurium) bacterial strains in individual pure culture growth assays. The potential of CH as a comparable 5kDaR substitute was also evaluated. The 5kDaR increased lactobacilli counts and butyrate concentration in the batch fermentation assay (P < 0.05) and increased L. plantarum (linear, P < 0.05), L. reuteri (quadratic, P < 0.05) and B. thermophilum (linear, P < 0.05) counts and reduced S. typhimurium (quadratic, P = 0.058) counts in the pure culture growth assays. CH increased butyrate concentration (P < 0.05) in the batch fermentation assay. YBG reduced Prevotella spp. counts (P < 0.05) and butyrate concentration (P < 0.05) in the batch fermentation assay. Both CH and YBG had no major effects in the pure culture growth assays. In conclusion, the 5kDaR had the most beneficial effects associated with increased counts of Lactobacillus and Bifidobacterium genera and butyrate production and reduced S. typhimurium counts in vitro indicating its potential to promote gastrointestinal health.

Partners in Infectious Disease: When Microbes Facilitate Enteric Viral Infections

The lumen of the gastrointestinal tract harbors a diverse community of microbes, fungi, archaea, and viruses. In addition to occupying the same enteric niche, recent evidence suggests that microbes and viruses can act synergistically and, in some cases, promote disease. In this review, we focus on the disease-promoting interactions of the gut microbiota and rotavirus, norovirus, poliovirus, reovirus, and astrovirus. Microbes and microbial compounds can directly interact with viruses, promote viral fitness, alter the glycan structure of viral adhesion sites, and influence the immune system, among other mechanisms. These interactions can directly and indirectly affect viral infection. By focusing on microbe–virus interplay, we hope to identify potential strategies for targeting offending microbes and minimizing viral infection.

Antimicrobial and Immunomodulatory Effects of Bifidobacterium Strains: A Review

Bifidobacterium strains can provide several health benefits, such as antimicrobial and immunomodulatory effects. Some strains inhibit growth or cell adhesion of pathogenic bacteria, including multidrug-resistant bacteria, and their antibacterial activity can be intensified when combined with certain antibiotics. In addition, some strains of bifidobacteria reduce viral infectivity, leading to less epithelial damage of intestinal tissue, lowering the virus shedding titer, and controlling the release of antiviral substances. Furthermore, bifidobacteria can modulate the immune system by increasing immunoglobulins, and inducing or reducing pro- or antiinflammatory cytokines, respectively. In particular, these anti-inflammatory effects are helpful in the treatment of patients who are already suffering from infection or inflammatory diseases. This review summarizes the antimicrobial effects and mechanisms, and immunomodulatory effects of Bifidobacterium strains, suggesting the potential of bifidobacteria as an alternative or complementary treatment option.

Effects of probiotics on chemotherapy in patients with lung cancer

Chemotherapy damages the intestinal mucosa, causing adverse gastrointestinal reactions. Clostridium butyricum (C. butyricum) reduces the incidence of diarrhea in digestive diseases, including inflammatory bowel disease. Therefore, the aim of the present study was to investigate the role of C. butyricum in patients undergoing chemotherapy. A total of 41 participants with lung cancer were enrolled, and divided into the C. butyricum (CB) or placebo group using 1:1 randomization to obtain 20 CB and 21 placebo participants. On the first and last day of the 3-week intervention, blood and stool samples were collected and analyzed. To analyze stool flora, 16S ribosomal RNA sequencing was performed. The incidence of chemotherapy-induced diarrhea was lower in the CB group compared with the placebo group. The lymphocyte count and platelet/lymphocyte ratio (PLR) was markedly altered between the two groups. Neutrophil/lymphocyte ratio (NLR) and PLR decreased within the CB group. At week 3, the lymphocyte/monocyte ratio (LMR) was higher in the CB group compared with the placebo group. Alterations in lymphocyte subsets and immunoglobulin levels were not significantly different. Albumin (ALB) level and weight did not differ significantly between the two groups. At 3 weeks the total flora diversity did not decrease in either group. Phyla in the CB group varied slightly, while the proportion of Firmicutes in the placebo group decreased significantly. No statistically significant difference was observed between the two groups, though the genera producing short-chain fatty acids tended to increase, and the pathogenic genera tended to decrease in the CB group, which was almost the opposite of the observation in the placebo group. Operational taxonomy unit analysis revealed a notable increase in beneficial flora, including the Clostridium and Lactobacillus genera of the CB group, compared with the placebo group. The present study highlighted that C. butyricum reduced chemotherapy-induced diarrhea in patients with lung cancer, reduced the systemic inflammatory response system and encouraged homeostatic maintenance.

Acute Infectious Diarrhea

Acute infectious diarrhea (AID) is one of the most common diseases in pediatric age with relevant burden both in high- and in low-income countries.Thanks to their direct action on enterocyte functions and indirect actions on mucosal and systemic immune system and intestinal microenvironment, probiotics are an ideal intervention to manage AID in childhood. However, their efficacy is strictly related to strains and indications, and practitioners should take this information into account in clinical practice.This chapter summarizes the main mechanisms of action of probiotics in AID, with a focus on proof of efficacy supporting their use in prevention and treatment of infant AID.The use of selected strains in appropriate doses is strongly recommended by guidelines of AID, based on large and consistent proofs of efficacy and safety. At present, therapy with probiotics of AID is arguably the strongest indication for probiotics in medicine. Future research should investigate probiotic efficacy in at-risk populations and settings where the evidence is missing.Their role in prevention of AID is however questionable in healthy population, whereas it should be considered in at-risk population. Evidence for prevention of diarrhea in day-care centers and communities is lacking, but consistent evidence supports efficacy in prevention of hospital acquired diarrhea.Overall, AID is the most convincing area for probiotic use in children, and effective strains should be used early after onset of symptoms.

An improved rat model for chronic inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is an important cause of chronic disability in humans.

METHODS

We characterized a model of chronic IBD in young male Wistar rats by administering dextran sodium sulfate (DSS: 0%, 0.25%, 0.5%, or 1% in drinking water) for six weeks, with 0.5% DSS for twelve weeks, following DSS cessation or together with treatment with sulfasalazine for the last 6 weeks. We measured gastrointestinal characteristics including stool consistency, blood in stools, small intestine and colon length, intestinal transit and permeability, and gut microbiota, as well as extra-intestinal parameters including oral glucose tolerance, systolic blood pressure, fat and lean mass, and left ventricular stiffness.

RESULTS

At 6 weeks, 0.25-1% DSS produced gastrointestinal changes as diarrhea and blood in stools. At 12 weeks, 0.5% DSS produced chronic and sustained gastrointestinal changes, with marked infiltration of inflammatory cells throughout the gastrointestinal tract and crypt distortion. Firmicutes increased and Bacteroidetes and Actinobacteria decreased in DSS-treated rats. Changes were reversed by DSS cessation or sulfasalazine treatment. Gastrointestinal permeability and extra-intestinal parameters did not change, so DSS changes were limited to the gastrointestinal tract.

CONCLUSION

Chronic 0.5% DSS produces selective and reversible gastrointestinal changes, providing an improved chronic model in rats that mimics human IBD for testing new interventions.

Oral administration of Bifidobacterium bifidum G9-1 alleviates rotavirus gastroenteritis through regulation of intestinal homeostasis by inducing mucosal protective factors

Human rotavirus (RV) infection is a leading cause of dehydrating diarrhea in infants and young children worldwide. Since therapeutic approaches to RV gastroenteritis are limited to alleviation of dehydration with oral rehydration solutions, more direct approaches to palliate symptoms of RV gastroenteritis are required. Treatments with probiotics have been increasingly recognized as alternative safe and low cost treatments for moderate infectious diarrhea. In this study, Bifidobacterium bifidum G9-1 (BBG9-1), which has been used as an intestinal drug for several decades, was shown to have a remarkable protective effect against RV gastroenteritis in a suckling mice model. As well as prophylactic oral administration of BBG9-1 from 2 days before RV infection, therapeutic oral administration of BBG9-1 from 1 day after RV infection significantly alleviated RV-induced diarrhea. Therapeutic administration of BBG9-1 reduced various types of damage in the small intestine, such as epithelial vacuolization and villous shortening, and significantly diminished the infectious RV titer in mixtures of cecal contents and feces. It was also shown that therapeutic administration of BBG9-1 significantly increased the number of acidic mucin-positive goblet cells and the gene expression of mucosal protective factors including MUC2, MUC3, MUC4, TGFβ1 and TFF3 in the small intestine. This led to alleviation of low gut permeability shown as decreased gene expression levels of occludin, claudin-1 and villin-1 after RV infection. Furthermore, in the small intestine, therapeutic administration of BBG9-1 significantly palliated the decreased gene expression of SGLT-1, which plays an important role in water absorption. In the large intestine, administered BBG9-1 was shown to replicate to assimilate undigested nutrients, resulting in normalization of the abnormally high osmotic pressure. These results suggested that water malabsorption caused by RV infection was alleviated in mice administered BBG9-1. Thus, the present study showed that oral administration of BBG9-1 palliated diarrhea partly through protection against RV-induced lesions by inducing mucosal protective factors. Oral administration of BBG9-1 is thought to be an efficient method for management of an RV epidemic for both prophylactic and therapeutic purposes.