Clinical trial: effect of active lactic acid bacteria on mucosal barrier function in patients with diarrhoea-predominant irritable bowel syndrome

Microbiome-based precision nutrition: Prebiotics, probiotics and postbiotics

Microorganisms have been used in nutrition and medicine for thousands of years worldwide, long before humanity knew of their existence. It is now known that the gut microbiota plays a key role in regulating inflammatory, metabolic, immune and neurobiological processes. This text discusses the importance of microbiota-based precision nutrition in gut permeability, as well as the main advances and current limitations of traditional probiotics, new-generation probiotics, psychobiotic probiotics with an effect on emotional health, probiotic foods, prebiotics, and postbiotics such as short-chain fatty acids, neurotransmitters and vitamins. The aim is to provide a theoretical context built on current scientific evidence for the practical application of microbiota-based precision nutrition in specific health fields and in improving health, quality of life and physiological performance.

Washed microbiota transplantation improves symptoms and intestinal barrier function in patients with functional bowel disorders: a propensity-score matching analysis

BACKGROUND

Alterations in the intestinal microbiota may play a role in the pathogenesis of functional bowel disorders (FBDs). Probiotics are widely used to improve intestinal dysbacteriosis in FBDs. In the context of FBDs, washed microbiota transplantation (WMT) appear to be a promising therapeutic option. We aimed to compare probiotics with WMT by using a propensity-score matching analysis (PSMA).

METHODS

We conducted a retrospective investigation of 103 patients with FBDs, including irritable bowel syndrome (IBS), functional constipation (FC), functional diarrhea (FDr), functional abdominal bloating (FAB). Patients were divided into the WMT group or probiotics group (taking probiotics capsules). Data on the following parameters were matched for PSMA: age; sex; disease course; body mass index; anxiety; insomnia; tobacco smoking; alcohol consumption; and levels of D-lactate, diamine oxidase, and lipopolysaccharide. Intestinal barrier function (IBF) and symptoms were evaluated both before and after treatment initiation. Prognostic factors were assessed by Cox proportional hazards regression analysis.

RESULTS

PSMA identified in 34 matched pairs (11 IBS, 12 FC, 7 FDr, and 4 FAB in the probiotics group and 14 IBS, 13 FC, 5 FDr, and 2 FAB in the WMT group. Improvement of FBD symptoms was greater with WMT than probiotics (P = 0.002). The WMT group had significantly fewer patients with intestinal barrier damage than the probiotics group (38.2% vs. 67.6%, P = 0.041). This improvement of FBD with WMT was further reflected as a reduction in D-lactate levels (P = 0.031). Increased D-lactate levels which were identified as a prognostic factor for FBDs (HR = 0.248, 95%CI 0.093-0.666, P = 0.006) in multivariate Cox regression analysis.

CONCLUSION

WMT could improve symptoms and IBF in patients with FBDs. Increased D-lactate levels in patients with FBDs may predict a favorable response to WMT treatment.

Efficacy of internet-based cognitive-behavioral therapy for depression in adolescents: A systematic review and meta-analysis

Objective

Internet-based cognitive behavior therapy (ICBT) may provide an accessible alternative to face-to-face treatment, but the evidence base in adolescents is limited. This systematic review and meta-analysis aims to comprehensively assess the efficacy of ICBT in addressing depression among adolescents.

Methods

Four electronic databases were searched on June 8, 2023. Randomized controlled trials (RCTs) evaluating the efficacy of ICBT for depression in adolescents were included. The quality of the studies was assessed using the risk of bias tool recommended by the Cochrane Handbook. Furthermore, the GRADE approach was employed to gauge the certainty of the obtained evidence. Meta-analysis was conducted using RevMan 5.4, and Egger's test was implemented through Stata for assessment of potential publication bias.

Results

A total of 18 RCTs involving 1683 patients were included. In comparison to control groups like attention control, waiting list, and treatment as usual, our meta-analysis findings elucidate a significant reduction in depression scores (SMD = -0.42, 95 % CI: [-0.74, -0.11], p < .05) as well as anxiety scores (SMD = -0.34, 95 % CI: [-0.60, -0.08], p < .05) in adolescents following ICBT interventions. Furthermore, the analysis indicated no notable distinctions in patient's quality of life (QoL) scores. (SMD = 0.12, 95 % CI: [-0.10, 0.34], p > .05).

Conclusion

Results provide evidence of the efficacy of ICBT to reduce depressive and anxiety symptoms in adolescents. These research findings are of vital significance for the establishment of evidence-based treatment guidelines in the digital era.

Trial registration

PROSPERO registration: CRD42021277562.

Outcome-Specific Efficacy of Different Probiotic Strains and Mixtures in Irritable Bowel Syndrome: A Systematic Review and Network Meta-Analysis

Irritable bowel syndrome (IBS) is a common gastrointestinal disease. The efficacy of different probiotics in treating IBS remains controversial. This network meta-analysis aimed to compare and rank the outcome-specific efficacy of different probiotic strains or combinations in adults with IBS. We searched the literature up to June 2023. Randomized controlled trials (RCTs) that evaluated the efficacy of probiotics in IBS were included. A frequentist framework was used to perform this study. In total, 9253 participants from 81 RCTs were included in the study. Four probiotic strains and five mixtures were significantly superior to placebo in improving IBS Symptom Severity Scale, among which Lactobacillus acidophilus DDS-1 ranked first (surface under the cumulative ranking, SUCRA, 92.9%). A mixture containing five probiotics (SUCRA, 100%) ranked first in improving the IBS-Quality of life. Bacillus coagulans MTCC 5856 (SUCRA, 96.9%) and Bacillus coagulans Unique IS2 (SUCRA, 92.6%) were among the most effective probiotics for improving abdominal pain. Three probiotic strains and two mixtures were effective in alleviating abdominal bloating. Four probiotic strains and a mixture were significantly superior to placebo in reducing the bowel movement frequency in diarrhea-predominant IBS (IBS-D). Bacillus coagulans MTCC 5856 (SUCRA, 99.6%) and Saccharomyces cerevisiae CNCM I-3856 (SUCRA, 89.7%) were among the most effective probiotics for improving the Bristol stool form scale of IBS-D. Only some probiotics are effective for particular outcomes in IBS patients. This study provided the first ranking of outcome-specific efficacy of different probiotic strains and combinations in IBS. Further studies are needed to confirm these results.

No Associations between Dairy Intake and Markers of Gastrointestinal Inflammation in Healthy Adult Cohort

Dairy products are a good source of essential nutrients and past reviews have shown associations of dairy consumption with decreased systemic inflammation. Links between dairy intake and gastrointestinal (GI) inflammation are under-investigated. Therefore, we examined associations between reported dairy intake and markers of GI inflammation in healthy adults in a cross-sectional observational study, hypothesizing a negative association with yogurt intake, suggesting a protective effect, and no associations with total dairy, fluid milk, and cheese intake. Participants completed 24-h dietary recalls and a food frequency questionnaire (FFQ) to assess recent and habitual intake, respectively. Those who also provided a stool sample (n = 295), and plasma sample (n = 348) were included in analysis. Inflammation markers from stool, including calprotectin, neopterin, and myeloperoxidase, were measured along with LPS-binding protein (LBP) from plasma. Regression models tested associations between dairy intake variables and inflammation markers with covariates: age, sex, and body mass index (BMI). As yogurt is episodically consumed, we examined differences in inflammation levels between consumers (>0 cup equivalents/day reported in recalls) and non-consumers. We found no significant associations between dairy intake and markers of GI inflammation. In this cohort of healthy adults, dairy intake was not associated with GI inflammation.

Constipation-Predominant Irritable Bowel Syndrome (IBS-C): Effects of Different Nutritional Patterns on Intestinal Dysbiosis and Symptoms

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder characterized by abdominal pain associated with defecation or a change in bowel habits. The pathogenesis of IBS is not completely clear, but it is known to be multifactorial and complex. Endogenous and exogenous factors such as abnormal GI motility, low-grade inflammation, increased epithelial permeability and visceral hypersensitivity, but diet and psychosocial aspects are also recognized as important actors. Furthermore, the interaction between diet and gut microbiota has gained interest as a potential contributor to the pathophysiology of IBS. To date, there is no specific diet for IBS with constipation (IBS-C); however, many studies show that fiber intake, especially soluble fiber such as inulin, could have a positive effect on symptoms. This review aims to evaluate the effects of some nutritional components such as fibers but also functional foods, prebiotics, probiotics and symbiotics on symptoms and microbiota in IBS-C subjects.

Probiotics in Irritable Bowel Syndrome: A Review Article

Irritable bowel syndrome (IBS) is a persistent set of symptoms that reduces one's goodness of life. The treatment of these people is usually focused on reducing the symptoms caused by the condition. This article examines the function of probiotics in alleviating symptoms in IBS patients. The goal of studying the impact of probiotics on IBS patients is to research the changes they cause to the gut microbiota, which may be beneficial in preventing and treating such diseases over time. This article also discusses the pathophysiology, diagnostic standards, therapeutic modalities, probiotic sources, and therapeutic relevance for IBS patients.

Could the Microbiota Be a Predictive Factor for the Clinical Response to Probiotic Supplementation in IBS-D? A Cohort Study

BACKGROUND

Increasing evidence suggests the beneficial effects of probiotics in irritable bowel syndrome (IBS), but little is known about how they can impact the gut microbiota. Our objective was to evaluate the effects of a multistrain probiotic on IBS symptoms, gut permeability and gut microbiota in patients with diarrhoea-predominant IBS (IBS-D).

METHODS

Adults with IBS-D were enrolled in an open-label trial to receive a multistrain probiotic for 4 weeks. Abdominal pain, stool frequency, quality of life, gut permeability, and the luminal and adherent microbiota from colonic biopsies were evaluated before and after supplementation.

RESULTS

Probiotics significantly improved symptoms and quality of life, despite having no impact on permeability in the global population. In the population stratified by the response, the diarrhoea responders displayed reduced colonic permeability after supplementation. The luminal and adherent microbiota were specifically altered depending on the patients' clinical responses regarding pain and diarrhoea. Interestingly, we identified a microbial signature in IBS-D patients that could predict a response or lack of response to supplementation.

CONCLUSIONS

The multistrain probiotic improved the symptoms of IBS-D patients and induced distinct effects on the gut microbiota according to the patient's clinical response and initial microbiota composition. Our study further supports the need to develop individualised probiotic-based approaches regarding IBS.

Probiotics therapy for adults with diarrhea-predominant irritable bowel syndrome: a systematic review and meta-analysis of 10 RCTs

PURPOSE

Accumulating evidence showed that probiotics therapy might be effective in treating diarrhea-predominant irritable bowel syndrome (IBS-D). This study aimed to evaluate the effectiveness and safety of probiotics therapy for the treatment of IBS-D.

METHODS

We performed a comprehensive literature search in eight electronic databases, and gray literature from inception to August 4, 2021. Randomized controlled trials (RCTs) of probiotics therapy for the treatment of IBS-D were included and the quality was assessed using the risk of bias tool recommended by the Cochrane Handbook version 5.1.0. RevMan 5.4 software was used to perform the meta-analysis on the outcomes of IBS-D symptoms, abdominal pain, quality of life, and abdominal distension. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the certainty of evidence.

RESULTS

Ten RCTs evaluating 943 patients were identified. Only one study had unclear risk of bias, while nine studies had a high risk of bias. The meta-analysis results showed that, compared to the placebo, probiotics therapy significantly decreased the score of IBS-D symptoms (SMD =  - 0.55, 95% CI: [- 0.83, - 0.27], P < 0.05), abdominal pain (SMD =  - 0.43, 95% CI: [- 0.57, - 0.29], P < 0.05), and abdominal distension (SMD =  - 0.45, 95%CI: [- 0.81, - 0.09], P < 0.05). There was no statistical difference in the quality of life. However, all the certainty of evidence was very low.

CONCLUSION

Very low certainty evidence showed that probiotics might be an effective treatment for improving the IBS-D symptoms, abdominal pain, and abdominal distension, in adult IBS-D patients. However, these conclusions should be supported by high-quality evidence.

Meta-analysis of the efficacy of probiotics to treat diarrhea

BACKGROUND

To collect the published trials of probiotics in the treatment of diarrhea and to strictly evaluate and systematically analyze the efficacy of probiotics use for the prevention and treatment of patients with diarrhea.

METHODS

We searched domestic and foreign literature published between January 2016 and July 2022 to find randomized control trials that used probiotics to treat diarrhea. Only studies published in English were considered. The quality of the included literatures was assessed by using the methods provided in the Cochrane Handbook. Valid data were extracted and analyzed by meta- analysis using the Software RevMan5.2.

RESULTS

Total 16 trials and 1585 patients were included. The results of the meta- analysis showed that in comparison with the simple Western medicine treatment group or placebo, the added use of probiotics could improve stool frequency, stool morphology, and related irritable bowel syndrome symptoms.

CONCLUSION

The added use of probiotics can further improve clinical outcomes in the patients with diarrhea; however, the implementation of larger and higher quality clinical trials is necessary to verify this conclusion.

Bacteroides fragilis ameliorates Cronobacter malonaticus lipopolysaccharide-induced pathological injury through modulation of the intestinal microbiota

Cronobacter has attracted considerable attention due to its association with meningitis and necrotizing enterocolitis (NEC) in newborns. Generally, lipopolysaccharide (LPS) facilitates bacterial translocation along with inflammatory responses as an endotoxin; however, the pathogenicity of Cronobacter LPS and the strategies to alleviate the toxicity were largely unknown. In this study, inflammatory responses were stimulated by intraperitoneal injection of Cronobacter malonaticus LPS into Sprague–Dawley young rats. Simultaneously, Bacteroides fragilis NCTC9343 were continuously fed through gavage for 5 days before or after injection of C. malonaticus LPS to evaluate the intervention effect of B. fragilis. We first checked the morphological changes of the ileum and colon and the intestinal microbiota and then detected the generation of inflammatory factors, including tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and interleukin-10 (IL-10) and the expression of Toll-like receptor 4 (TLR4), occludin, claudin-4, and iNOs. The results indicated that C. malonaticus LPS exacerbated intestinal infection by altering gut microbe profile, tight junction protein expression, and releasing inflammatory factors in a time- and dose-dependent manner. Intriguingly, treatment with B. fragilis obviously diminished the pathological injuries and expression of TLR4 caused by C. malonaticus LPS while increasing gut microbes like Prevotella-9. We note that Shigella, Peptoclostridium, and Sutterella might be positively related to C. malonaticus LPS infection, but Prevotella-9 was negatively correlated. The results suggested that the intestinal microbiota is an important target for the prevention and treatment of pathogenic injuries induced by C. malonaticus LPS.

Effect of a Multistrain Probiotic on Leaky Gut in Patients with Diarrhea-Predominant Irritable Bowel Syndrome: A Pilot Study

BACKGROUND

A probiotic mixture prevented epithelial barrier impairment in various experimental models. The objective was to evaluate its effects in patients suffering from IBS with diarrhea (IBS-D) with confirmed leaky gut.

METHODS

IBS-D patients with increased intestinal permeability measured by radionuclide tracers were enrolled in this pilot, open-label, prospective, interventional, single-center, Phase IV study. Patients received two capsules of a multistrain probiotic a day for 30 days and were evaluated by repeated intestinal permeability tests, the Bristol Stool Scale, and patient-perceived quality of life and satisfaction.

RESULTS

Of the 30 enrolled patients (mean age: 42.1 [SD: 13.1] years; female: 60%), 27 completed the study (full analysis set [FAS]), and 18 had no major protocol violation (per protocol set [PPS]). On D30, an improvement of intestinal permeability was observed in 81.5% of patients in FAS, normalization being observed in 37% of the participants (44% in PPS). The mean intestinal permeability was significantly decreased: baseline minus D30, 3.4 (95% CI: 1.7, 5.2); the IBS-QOL total score was significantly increased: D30 minus baseline, 8.0 (95% CI: 3.0, 12.9); and stool consistency was significantly improved. On D15 and D30, 96.3% of patients claimed that their IBS symptoms had been satisfactory alleviated, and a significant improvement was reported for the following VAS-IBS items: abdominal pain, diarrhea, and impact of gastrointestinal problems in daily life. Compliance and tolerance were satisfactory.

CONCLUSION

The multistrain probiotic tested may reduce intestinal permeability in a considerable proportion of patients and may improve abdominal pain, stool consistency, and quality of life. These results pave the way for larger, placebo-controlled clinical studies.

Pharmacokinetic Differences of Wuji Pill Components in Normal and Chronic Visceral Hypersensitivity Irritable Bowel Syndrome Rats Attributable to Changes in Tight Junction and Transporters

The Wuji pill, also called Wuji Wan (WJW), is an effective traditional medicine for the clinical treatment of irritable bowel syndrome (IBS). It is principally composed of Rhizoma Coptidis, Fructus Evodiae Rutaecarpae, and Radix Paeoniae Alba. There have been no reports on the pharmacokinetics of WJW on IBS. Because it is more meaningful to study pharmacokinetics in relation to specific pathological conditions, our study investigated the pharmacokinetic differences of five representative components (berberine, palmatine, evodiamine, rutaecarpine, and paeoniflorin) in normal rats and chronic visceral hypersensitivity IBS (CVH-IBS) model rats after single dose and multiple doses of WJW using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Transmission electron microscopy, immunohistochemistry, and immunofluorescence were used to explore mechanisms behind the pharmacokinetic differences in terms of tight junction proteins (Occludin and ZO-1), myosin light chain kinase (MLCK), and transporters including P-glycoprotein (P-gp), multidrug resistance associated protein 1 (MRP1), and multidrug resistance associated protein 2 (MRP2) in rat colons. After a single dose, for all components except rutaecarpine, significant differences were observed between normal and model groups. Compared with normal group, T_1/2 and AUC_0-t of berberine and palmatine in model group increased significantly (562.5 ± 237.2 vs. 1,384.9 ± 712.4 min, 733.8 ± 67.4 vs. 1,532.4 ± 612.7 min; 5,443.0 ± 1,405.8 vs. 9,930.8 ± 2,304.5 min·ng/ml, 2,365.5 ± 410.6 vs. 3,527.0 ± 717.8 min·ng/ml), while Cl/F decreased (840.7 ± 250.8 vs. 397.3 ± 142.7 L/h/kg, 427.7 ± 89.4 vs. 288.9 ± 114.4 L/h/kg). C_max and AUC_0-t of evodiamine in model group increased significantly (1.4 ± 0.6 vs. 2.4 ± 0.7 ng/ml; 573 ± 45.3 vs. 733.9 ± 160.2 min·ng/ml), while T_1/2, T_max, Cl/F, and Vd/F had no significant difference. T_max and AUC_0-t of paeoniflorin in model group increased significantly (21.0 ± 8.2 vs. 80.0 ± 45.8 min; 15,428.9 ± 5,063.6 vs. 33,140.6 ± 5,613.9 min·ng/ml), while Cl/F decreased (110.5 ± 48.1 vs. 43.3 ± 9.5 L/h/kg). However, after multiple doses, all five components showed significant differences between normal and model groups. Moreover, these differences were related to tight junction damage and the differential expression of transporters in the colon, suggesting that dose adjustment might be required during administration of WJW in the clinical treatment of IBS.

The Probiotic Lactobacillus paracasei Ameliorates Diarrhea Cause by Escherichia coli O8via Gut Microbiota Modulation1

Introduction

Koumiss is a fermented horse milk food containing abundant probiotics. Lactobacillus paracasei is a bacterial strain isolated from koumiss that helps regulate the intestinal microbiota. One of the major cause of diarrhea is an imbalance of the intestinal flora. The aim of this study was to investigate whether Lactobacillus paracasei can ameliorate E. coli-induced diarrhea and modulate the gut microbiota.

Methods

Mouse models of diarrhea were established via intragastric E. coli O₈ administration. We then attempted to prevent or treat diarrhea in the mice via intragastric administration of a 3 × 10⁸ CFU/mL L. paracasei cell suspension. The severity of diarrhea was evaluated based on the body weight, diarrhea rate, and index, fecal diameter, ileum injury, hematoxylin-eosin (H&E) staining, and diamine oxidase (DAO) and zonulin expression. Expression of the tight junction (TJ) proteins claudin-1, occludin, and zona occludens (ZO-)1 were detected by immunohistochemistry (IHC). Gastrointestinal mRNA expression levels of interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α were detected by real-time polymerase chain reaction (RT-PCR). The microbial composition was analyzed by 16s rRNA sequencing.

Results

The L. paracasei demonstrated excellent therapeutic efficacy against diarrhea. It elevated the TJ protein levels and downregulated proinflammatory cytokines IL-6, IL-1β, TNF-α, and p65, myosin light chain 2 (MLC2), myosin light chain kinase (MLCK). Moreover L. paracasei increased those bacteria, which can product short-chain fatty acid (SCFA) such Alistipes, Odoribacter, Roseburia, and Oscillibacter.

Conclusion

L. paracasei ameliorated diarrhea by inhibiting activation of the nuclear factor kappa B (NF-κB)-MLCK pathway and increasing the abundance of gut microbiota that produce SCFA.

Efficacy of Probiotics for Irritable Bowel Syndrome: A Systematic Review and Network Meta-Analysis

Background

Irritable bowel syndrome (IBS) is a common gastrointestinal condition. Studies regarding the treatment of IBS with probiotics have not yielded consistent results, and the best probiotics has not yet been confirmed. Therefore, we performed a network meta-analysis (NMA) to assess the relative rank order of different probiotics for IBS.

Method

We searched for RCTs on the efficacy of probiotics for IBS until August 25, 2021. The primary outcome was the symptom relief rate, as well as global symptoms, abdominal pain, bloating, and straining scores. The NMA was conducted using Stata 15.0. We also used meta-regression to explore whether the treatment length and dose influenced the efficacy.

Results

Forty-three RCTs, with 5,531 IBS patients, were included in this analysis. Firstly, we compared the efficacy of different probiotic species. B.coagulans exhibited the highest probability to be the optimal probiotic specie in improving IBS symptom relief rate, as well as global symptom, abdominal pain, bloating, and straining scores. In regard to the secondary outcomes, L.plantarum ranked first in ameliorating the QOL of IBS patients, but without any significant differences compared with other probiotic species in standardized mean differences (SMD) estimates. Moreover, patients received L.acidophilus had lowest incidence of adverse events. The meta-regression revealed that no significant differences were found between participants using different doses of probiotics in all outcomes, while the treatment length, as a confounder, can significantly influence the efficacy of probiotics in ameliorating abdominal pain (Coef = -2.30; p = 0.035) and straining (Coef = -3.15; p = 0.020) in IBS patients. Thus, we performed the subgroup analysis on treatment length subsequently in these two outcomes, which showed that efficacy of B.coagulans using 8 weeks ranked first both in improving the abdominal pain and straining scores. Additionally, B. coagulans still had significant efficacy compared to different types of probiotic combinations in present study.

Conclusions

The findings of this NMA suggested that B.coagulans had prominent efficacy in treating IBS patients, and incorporating B.coagulans into a probiotic combination, or genetically engineering it to amplify its biological function may be a future research target to treat IBS patients. With few direct comparisons available between individual therapies today, this NMA may have utility in forming treatment guideline for IBS with probiotics.

Low FODMAP Diet and Probiotics in Irritable Bowel Syndrome: A Systematic Review With Network Meta-analysis

Background: Probiotic and low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) diet are two commonly used management approaches for patients with irritable bowel syndrome (IBS). We aimed to evaluate the most effective combinations and components among different probiotics or low FODMAP diet through component network meta-analysis (NMA).

Methods: We searched Embase, Ovid Medline, and Web of Science from inception to 21 January 2021. Randomized controlled trials (RCTs) examining the efficacy of probiotics and low FODMAP diet for IBS were included, with placebo, sham diet, or conventional treatments as controls. Binary outcomes were compared among treatments using the relative ratio (RR). A minimally contextualized framework recommended by the GRADE group was used to evaluate the certainty of evidence. The primary efficacy outcome was the relief of global IBS symptoms, and the secondary efficacy outcome was the reduction in IBS symptom scores or abdominal pain scores.

Key Results: We included 76 RCTs (n = 8058) after screening 1940 articles. Eight RCTs were classified as low risk of bias. Standard network meta-analysis (NMA) showed that Lactobacillus (RR 1.74, 95% CI 1.22–2.48) and Bifidobacterium (RR 1.76, 95% CI 1.01–3.07) were the most effective for the primary efficacy outcome (high certainty evidence); component NMA showed that Bacillus (RR 5.67, 95% CI 1.88 to 17.08, p = 0.002) and Lactobacillus (RR 1.42, 95% CI 1.07 to 1.91, p = 0.017) were among the most effective components. The results of standard NMA and CNMA analysis of the improvement of overall IBS symptom scores or abdominal pain scores were consistent with this finding.

Conclusion:Lactobacillus was the most effective component for the relief of IBS symptoms; Bifidobacterium and Bacillus were possibly effective and need further verification.

Systematic Review Registration: website, identifier registration number.

Lactobacillus paracasei BD5115-Derived 2-Hydroxy-3-Methylbutyric Acid Promotes Intestinal Epithelial Cells Proliferation by Upregulating the MYC Signaling Pathway

Metabolites of probiotics that are beneficial to human health have been isolated from the intestinal tract and natural dairy products. However, many studies on probiotics and prebiotics are limited to the observation of human cohorts and animal phenotypes. The molecular mechanisms by which metabolites of probiotics regulate health are still need further exploration. In this work, we isolated a strain of Lactobacillus Paracasei from human milk samples. We numbered it as Lactobacillus Paracasei BD5115. The mouse model of high-fat diet confirmed that the metabolites of this strain also promotes intestinal epithelial cells (IECs) proliferation. Single-cell sequencing showed that a bZIP transcription factor MAFF was specifically expressed in some IECs. We found that MAFF interacted with MBP1 to regulate the expression of MYC. Analysis of the active components in BD5115 metabolites confirmed that 2-hydroxy-3-methylbutyric acid promotes the expression of the MYC gene. This promotes the proliferation of IECs. Our findings indicate that 2-hydroxy-3-methylbutyric acid regulate MYC gene expression mediated by MAFF/MBP1 interaction. This study not only screened a strain with promoted IECs proliferation, but also discovered a new signal pathway that regulates MYC gene expression.

Mechanism of QingHuaZhiXie Prescription Regulating TLR4-IECs Pathway in the Intervention of Diarrhea Predominant Irritable Bowel Syndrome

To investigate the effect and mechanism of QingHuaZhiXie prescription on diarrhea predominant irritable bowel syndrome (D-IBS), animal models of rats were used in this study. 48 rats were randomly divided into 6 groups, containing one control group, one animal model group (D-IBS group), and four drug intervention groups (low, medium, and high dosage of QingHuaZhiXie prescription and trimebutine maleate intervention group). Abdominal withdrawal reflex (AWR) and Bristol stool form scale were recorded; the expression levels of inflammatory factors (TNF-α and IFN-γ), pathway proteins TLR4, MyD88, NF-κB, and key proteins of tight junction between intestinal epithelial cells (IECs) were detected; the microstructure of intestinal mucosal was observed by hematoxylin and eosin (H&E) staining; MPO activity was detected with immunohistochemical analysis to reflect the inflammation of tissues. Results show that QingHuaZhiXie prescription reduced diarrhea index and intestinal hypersensitivity and intestinal tissue integrity after intervention. MPO activity in QingHuaZhiXie prescription-treated rats was significantly lower relative to their model group. The expression levels of inflammatory factors and TLR4/MyD88/NF-κB pathway proteins were repressed, and the protein levels of occludin and claudin-1 increased. Meanwhile, this study also found that the remission effect of QingHuaZhiXie prescription on D-IBS increased with its dosage increase. Hence, as a therapeutic prescription for D-IBS, QingHuaZhiXie prescription could relieve D-IBS symptoms through balancing the inflammatory factors expression by inhibiting the TLR4/MyD88/NF-κB pathway and maintaining the function and structure of IECs by improving the protein levels of JAM, occludin, claudin-1, and ZO-1.

How can probiotic improve irritable bowel syndrome symptoms?

The onset and manifestations of irritable bowel syndrome (IBS) is associated with several factors, and the pathophysiology involves various central and peripheral mechanisms. Most studies indicate that the management of gut microbiota could significantly affect the improvement of subjective disorders in patients with IBS. Numerous clinical trials have assessed the efficacy of probiotics for IBS with controversial conclusions. Several clinical trials have suggested that probiotics can improve global IBS symptoms, while others only improve individual IBS symptoms, such as bloating scores and abdominal pain scores. Only a few clinical trials have found no apparent effect of probiotics on IBS symptoms. Generally, probiotics appear to be safe for patients with IBS. However, the question of which probiotics should be used for certain IBS subtypes remains unresolved. In everyday practice, the dose of the recommended probiotic remains questionable, as well as how long the probiotic should be used in therapy. The use of probiotics in the M subtype and non-classified IBS is particularly problematic, in which combination therapy should be recommended due to the change in symptoms. Therefore, new approaches are needed in the design of clinical studies that should address certain subtypes of IBS.

Clostridium butyricum relieve the visceral hypersensitivity in mice induced by Citrobacter rodentium infection with chronic stress

Background

Visceral hypersensitivity is a common symptom in patients with post-infectious irritable bowel syndrome (PI-IBS), and change of the microbiota is a vital etiological factor of it. Clostridium butyricum (C. butyricum) is one of the probiotics which is reported as the active components in the treatment of IBS, especially IBS with diarrhea. Citrobacter rodentium (C. rodentium) is an enteropathogenic bacteria which can produce self-limiting colitis in mice, which have been used to produce a PI-IBS-like mice model. Whether C. butyricum could influence the visceral hypersensitivity and gut microbiota of PI-IBS is still unknown. Our study aimed to examine whether the intervention of C. butyricum or antibiotics could affect the etiology of visceral hypersensitivity.

Methods

C57BL/6 male mice were gavaged with the C. rodentium to induce a infective colitis. The C. butyricum and antibiotic compound were used to intervene the infected mice 3 days later. A 9-day chronic water avoidance stress (WAS) process was implemented to help induce the visceral hypersensitivity. The abdominal withdrawal reflex (AWR) score was assayed to indicate the visceral hypersensitivity of different groups. On the 7th, 14th, and 30th days after infection, mice feces were collected and high-throughput sequencing was carried out to analyze their gut microbiota.

Results

Combined, the C. rodentium infection plus chronic stress (WAS) could induce the visceral hypersensitivity in mice. Treatment of the C. butyricum after C. rodentium infection could relieve visceral hypersensitivity of mice, while no difference was observed in the antibiotic treatment group. The gut microbiota diversity of C. rodentium infected mice was similar to the uninfected mice, while there were different microbial communities structure between them. The Shannon and Chao indexes significantly decreased in the antibiotic treatment group compared to other groups at 7th, 14th, and 30th days post-infection, while treatment of C. butyricum could maintain the indexes within normal range. At day 14 after infection, the structure of microbiota headed towards normality after the C. butyricum treatment. After the WAS, the Shannon and Chao indexes of the control group decreased and the structure of microbiota changed. The C. butyricum treatment could prevent these changes of the gut microbiota induced by WAS.

Conclusion

C. butyricum could relieve the visceral hypersensitivity in mice induced by C. rodentium infection plus chronic stress. It could also remodel the microbiota change caused by the infection and chronic stress. It may be a more effective treatment strategy for PI-IBS than antibiotics.

Probiotics, Prebiotics, and Synbiotics: Implications and Beneficial Effects against Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is still a common functional gastrointestinal disease that presents chronic abdominal symptoms but with a pathophysiology that is not yet fully elucidated. Moreover, the use of the synergistic combination of prebiotics and probiotics, known as synbiotics, for IBS therapy is still in the early stages. Advancements in technology led to determining the important role played by probiotics in IBS, whereas the present paper focuses on the detailed review of the various pathophysiologic mechanisms of action of probiotics, prebiotics, and synbiotics via multidisciplinary domains involving the gastroenterology (microbiota modulation, alteration of gut barrier function, visceral hypersensitivity, and gastrointestinal dysmotility) immunology (intestinal immunological modulation), and neurology (microbiota–gut–brain axis communication and co-morbidities) in mitigating the symptoms of IBS. In addition, this review synthesizes literature about the mechanisms involved in the beneficial effects of prebiotics and synbiotics for patients with IBS, discussing clinical studies testing the efficiency and outcomes of synbiotics used as therapy for IBS.

Digestive system manifestations and clinical significance of coronavirus disease 2019: A systematic literature review

BACKGROUND AND AIM

A worldwide outbreak of coronavirus disease 2019 (COVID-19) has drawn global attention. Several reports have described the gastrointestinal (GI) manifestations in the infected patients. The systematic review was designed to highlight the gaps in our knowledge about the prevalence and clinical significance of GI symptoms in patients with COVID-19.

METHODS

We searched PubMed database and Google articles published in both English and Chinese up to June 3, 2020, using search terms "clinical features," "2019 novel coronavirus," "2019-nCoV," "COVID-19," or "SARS-Cov-2." Observational studies, case reports, or letters describing the clinical features or observational studies regarding the detection and/or isolation of severe acute respiratory syndrome coronavirus 2 viruses in stools were included.

RESULTS

A total of 22 publications were finally selected. It was reported that GI symptoms occurred in about 3-40.7% of patients. GI manifestations included nausea, diarrhea, anorexia, vomiting, abdominal pain, belching, abdominal distension, and GI hemorrhage. Diarrhea was the most common GI symptom. Infected patients had various degrees of liver dysfunction, and the severity of liver dysfunction was significantly associated with the severity of the disease. Therapy focusing on digestive system like liver supportive therapy or nutrition support or probiotics has been demonstrated to be effective interventions, which greatly improve prognosis. Fecal-oral transmission route is a potential risk for transmission.

CONCLUSIONS

GI symptoms are common in COVID-19. Strengthening the recognition on abnormalities in digestive system of patients with COVID-19 is crucial for early identification and timely treatment, especially for those atypical patients. Hygiene protection and keeping the drainpipe free flowing are necessary for everyone.

Yogurt, cultured fermented milk, and health: a systematic review

Consumption of yogurt and other fermented products is associated with improved health outcomes. Although dairy consumption is included in most dietary guidelines, there have been few specific recommendations for yogurt and cultured dairy products. A qualitative systematic review was conducted to determine the effect of consumption of fermented milk products on gastrointestinal and cardiovascular health, cancer risk, weight management, diabetes and metabolic health, and bone density using PRISMA guidelines. English language papers in PubMed were searched, with no date restrictions. In total, 1057 abstracts were screened, of which 602 were excluded owing to lack of appropriate controls, potential biases, and experimental design issues. The remaining 455 papers were independently reviewed by both authors and 108 studies were included in the final review. The authors met regularly to concur, through consensus, on relevance, methods, findings, quality, and conclusions. The included studies were published between 1979 and 2017. From the 108 included studies, 76 reported a favorable outcome of fermented milks on health and 67 of these were considered to be positive or neutral quality according to the Academy of Nutrition and Dietetics’ Quality Criteria Checklist. Of the 32 remaining studies, the study outcomes were either not significant (28) or unfavorable (4), and most studies (18) were of neutral quality. A causal relationship exists between lactose digestion and tolerance and yogurt consumption, and consistent associations exist between fermented milk consumption and reduced risk of breast and colorectal cancer and type 2 diabetes, improved weight maintenance, and improved cardiovascular, bone, and gastrointestinal health. Further, an association exists between prostate cancer occurrence and dairy product consumption in general, with no difference between fermented and unfermented products. This article argues that yogurt and other fermented milk products provide favorable health outcomes beyond the milk from which these products are made and that consumption of these products should be encouraged as part of national dietary guidelines.

Systematic review registration: PROSPERO registration no. CRD42017068953.

Enterococcus faecium R0026 Combined with Bacillus subtilis R0179 Prevent Obesity-Associated Hyperlipidemia and Modulate Gut Microbiota in C57BL/6 Mice

Bacillus subtilis and Enterococcus faecium are commonly used probiotics. This study aimed to identify the effect of live combined Bacillus subtilis R0179 and Enterococcus faecium R0026 (LCBE) on obesityassociated hyperlipidemia and gut microbiota in C57BL/6 mice. Forty male C57BL/6 mice were divided into four groups: normal group (N group), model group (M group), low-dose group (L group), and high-dose group (H group). Mice were gavaged with LCBE at 0.023 g/mice/day (L group) or 0.23 g/mice/day (H group) and fed with a high-fat diet for 8 weeks. In vitro E. faecium R0026 showed an ability to lower the low-concentration of cholesterol by 46%, and the ability to lower the highconcentration of cholesterol by 58%. LCBE significantly reduced the body weight gain, Lee index, brown fat index and body mass index of mice on a high-fat diet. Moreover, LCBE markedly improved serum lipids (including serum triglyceride, total cholesterol, low-density lipoprotein and highdensity lipoprotein) while also significantly reducing liver total cholesterol. Serum lipopolysaccharide and total bile acid in L and H groups decreased significantly compared with M group. PCR-DGGE analysis showed that the composition of gut microbiota in the treatment groups was improved. Akkermansia muciniphila was found in H group. The PCA result indicated a similar gut microbiota structure between LCBE treatment groups and normal group while the number of bands and Shannon diversity index increased significantly in the LCBE treatment groups. Finally, qPCR showed Bifidobacterium spp. increased significantly in H group compared with M group, LCBE alleviated liver steatosis and improved brown adipose tissue index.

Intestinal barrier dysfunction in irritable bowel syndrome: a systematic review

BACKGROUND AND AIM

Irritable bowel syndrome (IBS) is a complex and heterogeneous disorder. Sensory, motor and barrier dysfunctions are the key physiological endophenotypes of IBS. Our aim is to review studies evaluating barrier dysfunction in adults and children with IBS, as well as to link those changes with IBS symptomatology and quality of life.

METHODS

A comprehensive and systematic review of multiple databases was performed up to March 2020 to identify studies comparing intestinal permeability in IBS patients with healthy controls. Both in vivo and in vitro studies were considered.

RESULTS

We identified 66 studies, of which 27 used intestinal probes to quantify barrier function. The prevalence of barrier dysfunction differed between PI-IBS (17-50%), IBS-D (37-62%) and IBS-C (4-25%). At a group level, permeability was increased compared with healthy controls in IBS-D (9/13 studies) and PI-IBS (4/4 studies), but only a minority of IBS-C (2/7 studies) and not in the only IBS-M study. All four studies in children with IBS demonstrated loss of barrier function. A heterogeneous set of tight junction genes were found to be altered in small and large intestines of adults with IBS, but these have not been evaluated in children. Positive associations were identified between barrier dysfunction and bowel disturbances (6/9 studies), abdominal pain (9/13 studies), overall symptom severity (1/6 studies), depression and anxiety (1/1 study) and quality of life (1/4 studies). Fecal slurry or supernatants of IBS patients were found to induce barrier disruption in animal models (5/6 studies).

CONCLUSIONS

Barrier dysfunction is present in a significant proportion of adult and all pediatric IBS studies, especially in the IBS-D and PI-IBS subtype. The majority of studies indicated a positive association between loss of barrier function and symptoms such as abdominal pain and changes in the bowel function.

Yogurt Consumption Is Associated with Lower Levels of Chronic Inflammation in the Framingham Offspring Study

Some studies suggest that dairy foods may be linked with less chronic inflammation. However, few studies have investigated the separate effects of different types of dairy on inflammation. Therefore, the current study aims to examine the separate prospective impacts of milk, yogurt and cheese on biomarkers of chronic inflammation in 1753 community-dwelling participants of the Framingham Offspring Study (FOS). Mean intakes of dairy foods were derived from two sets of three-day diet records. Six inflammatory biomarkers were assessed approximately seven years later at exam 7. Results showed that those who consumed yogurt (vs. those who did not) had statistically significantly lower levels of interleukin-6 (IL-6) (mean log-transformed levels of 1.31 and 1.26 in consumers/non-consumers, respectively, p = 0.02) and fibrin (mean log-transformed levels of 5.91 and 5.89 in consumers/non-consumers, respectively, p = 0.03). The inverse association between IL-6 and yogurt consumption was similar in participants who were of normal weight and those who were overweight. For fibrin, the effects were stronger in overweight individuals. No statistically significant associations were observed between any of these inflammation biomarkers and milk or cheese intakes. Overall, our study compared the separate impacts of three types of dairy foods on chronic inflammation and found that only yogurt intake was linked with lower levels of chronic inflammation.

Lactobacillus bulgaricus inhibits colitis-associated cancer via a negative regulation of intestinal inflammation in azoxymethane/dextran sodium sulfate model

BACKGROUND

Colitis-associated cancer (CAC) accounts for 2%-3% of colorectal cancer (CRC) cases preceded by inflammatory bowel diseases (IBD) such as Crohn's disease and ulcerative colitis. Intestinal microbiota has been reported to play a central role in the pathogenesis of IBD and CAC. Recently, numerous prebiotics and probiotics have being investigated as antitumor agents due to their capacity to modulate inflammatory responses. Previous studies have indicated that lactic acid bacteria could be successfully used in managing sporadic CRC, however little is known about their role in CAC.

AIM

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

METHODS

C57BL/6 mice received an intraperitoneal injection of azoxymethane (10 mg/kg), followed by three cycles of sodium dextran sulphate diluted in water (5% w/v). Probiotic group received daily L. bulgaricus. Intestinal inflammation was determined by scoring clinical signs. Cytokines levels were determined from colon and/or tumor samples by ELISA BD OptEIATM kits. The level of significance was set at P < 0.05. Graphs were generated and statistical analysis performed using the software GraphPad Prism 6.0.

RESULTS

L. bulgaricus treatment inhibited of total tumor volume and mean size of tumors. In addition, the probiotic also attenuated the clinical signs of intestinal inflammation inducing a decrease in intestinal and tumor levels of IL-6, TNF-α, IL-17, IL-23 and IL-1β.

CONCLUSION

Our results suggest a potential chemopreventive effect of probiotic on CAC. L. bulgaricus regulates the inflammatory response and preventing CAC.

Noninvasive Biomarkers of Gut Barrier Function in Patients Suffering from Diarrhea Predominant-IBS: An Update

The intestinal barrier plays a crucial role in the absorption of nutrients and in preventing the entry of pathogenic microorganisms and toxic molecules. Several studies have shown a compromised intestinal barrier associated with low-grade inflammation in the small intestinal mucosa in celiac disease, inflammatory bowel disease, and irritable bowel syndrome (IBS), particularly in IBS with diarrhea (IBS-D). In light of these new data, IBS is no longer considered a functional disease but rather a heterogeneous syndrome that has yet to be carefully studied. Therefore, investigating the integrity and function of the intestinal barrier is now essential to improving knowledge of the pathophysiology of IBS-D and to improving the management of IBS-D patients. However, the study of the intestinal barrier must clarify some still unsolved methodological aspects and propose standardised assays before becoming a useful diagnostic tool. In this framework, this review will discuss data about the tests that noninvasively evaluate the integrity and functionality of the human intestinal barrier, paying particular attention to patients with IBS-D, in both clinical and research situations.

Increasing Evidence That Irritable Bowel Syndrome and Functional Gastrointestinal Disorders Have a Microbial Pathogenesis

The human gastrointestinal tract harbors most of the microbial cells inhabiting the body, collectively known as the microbiota. These microbes have several implications for the maintenance of structural integrity of the gastrointestinal mucosal barrier, immunomodulation, metabolism of nutrients, and protection against pathogens. Dysfunctions in these mechanisms are linked to a range of conditions in the gastrointestinal tract, including functional gastrointestinal disorders, ranging from irritable bowel syndrome, to functional constipation and functional diarrhea. Irritable bowel syndrome is characterized by chronic abdominal pain with changes in bowel habit in the absence of morphological changes. Despite the high prevalence of irritable bowel syndrome in the global population, the mechanisms responsible for this condition are poorly understood. Although alterations in the gastrointestinal microbiota, low-grade inflammation and immune activation have been implicated in the pathophysiology of functional gastrointestinal disorders, there is inconsistency between studies and a lack of consensus on what the exact role of the microbiota is, and how changes to it relate to these conditions. The complex interplay between host factors, such as microbial dysbiosis, immune activation, impaired epithelial barrier function and motility, and environmental factors, including diet, will be considered in this narrative review of the pathophysiology of functional gastrointestinal disorders.

[Functional diseases of the gastrointestinal tract in the context with overlapping functional disorders: current status of the problem]

Functional diseases of the gastrointestinal tract cause significant damage to the health care system. Their frequent combination in the same patient with the migration of clinical symptoms throughout the digestive tube is accompanied by continuous exacerbations, refractory to the therapy and severe psychosocial disorders. This review provides data on the main etiopathogenetic factors, clinical manifestations, course features and management tactics for patients with overlapping for the most common functional diseases of the gastrointestinal tract.

Efficacy and Safety of Probiotics in Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis

Background

Irritable bowel syndrome is a functional gastrointestinal disease. Evidence has suggested that probiotics may benefit IBS symptoms. However, clinical trials remain conflicting.

Aims

To implement a systematic review and meta-analysis of clinical trials regarding the efficacy and safety of probiotics for IBS patients.

Methods

We searched for relevant trials in Medline(1966 to Jan 2019), Embase(1974 to Jan 2019), the Cochrane Central Register of Controlled Trials(up to Jan 2019), the ClinicalTrials.gov trials register(up to Jan 2019), and Chinese Biomedical Literature Database(1978 to Jan 2019). Risk ratio (RR) and a 95% confidence interval (CI) were calculated for dichotomous outcomes. Standardized mean difference (SMD) and 95% CI were calculated for continuous outcomes.

Results

A total of 59 studies, including 6,761 patients, were obtained. The RR of the improvement or response with probiotics versus placebo was 1.52 (95% CI 1.32-1.76), with significant heterogeneity (I² = 71%, P < 0.001). The SMD of Probiotics in improving global IBS symptoms vs. Placebo was -1.8(95% CI -0.30 to -0.06), with significant heterogeneity (I² = 65%, P < 0.001). It was impossible to draw a determinate conclusion. However, there were differences in subgroup analyses of probiotics type, dose, treatment duration, and geographic position. Probiotics seem to be safe by the analysis of adverse events(RR = 1.07; 95% CI 0.92-1.24; I² = 0, P = 0.83).

Conclusion

Probiotics are effective and safe for IBS patients. Single probiotics with a higher dose (daily dose of probiotics ≥10¹⁰) and shorter duration (< 8 weeks) seem to be a better choice, but it still needs more trials to prove it.

Efficacy and safety of probiotics in irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND/AIM

Irritable Bowel Syndrome (IBS) is a common chronic functional bowel disorder and the evidence shows most drug therapies in the treatment of IBS are weak. Recently, some studies showed probiotics may have a positive effect in IBS and they are widely used to improve the symptom of IBS, which indicate probiotics may play an important role in the treatment of IBS. However, the exact effectiveness and safety of probiotics are largely unknown. This systematic review focuses on identifying the efficacy and safety of probiotics in the treatment of IBS.

MATERIALS AND METHODS

Data sources were searched up to February 2019. Databases included MEDLINE, CENTRAL, CINAHL, and Embase. Randomized controlled trials (RCTs) comparing probiotics including complex or individual probiotics with placebo or no therapy were screened, extracted, and appraised by two independent reviewers. The data were pooled using a random-effects model. The methodological quality of all RCTs was assessed using the Cochrane risk of bias and Jadad scale. Outcomes included symptom-relevant and patient-relevant characteristics, such as symptom relief, abdominal pain, bloating, flatulence, quality of life, and adverse event.

RESULTS

This review includes 28 studies with a total of 3606 participants. Particular combinations of probiotics, or specific species and strains, showed probiotics have beneficial effect on overall IBS symptoms (22 studies, n = 3144, RR of improvement in overall IBS symptoms = 1.5, CI 1.23 to 1.83) or overall IBS symptom and abdominal pain scores (18 studies, n = 2766, SMD = -0.31, CI -0.45 to -0.17). In addition, adverse events were not significantly higher with probiotics (8 studies, n = 923, RR = 1.05; 95% CI 0.85-1.31). However, there was no significant benefit on individual IBS symptom scores and quality of life.

CONCLUSION

Current evidence shows particular combinations, species or strains of probiotics are effective for overall IBS symptoms. However, it is hard to derive a definite conclusion due to high heterogeneity and unclear risk of bias of some trials. Large well-designed and rigorous trials are warranted.

Effects of Bifidobacterium longum BB536 and Lactobacillus rhamnosus HN001 in IBS patients

BACKGROUND

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder, which still lacks effective therapy. We aimed to investigate the effects of a novel formulation of Bifidobacterium longum BB536 and Lactobacillus rhamnosus HN001 with vitamin B6 (LBB) on symptoms, intestinal permeability, cultivable bacteria and metabolome in IBS subjects.

MATERIALS AND METHODS

Twenty-five IBS patients (Rome IV criteria) (M:F = 8:17; age 48 years ± 11 SD) were randomized to treatment (LBB) or placebo (one month each) in a crossover randomized double-blind controlled trial. Symptoms, intestinal habits, disease severity, intestinal permeability and intestinal microbiota were analysed at 0, 30, 45 and 60 days.

RESULTS

Percentage decrease from baseline of abdominal pain (-48.8% vs -3.5%), bloating (-36.35% vs +7.35%) and severity of disease (-30.1% vs -0.4%) was significantly (P < .0001) greater with LBB than placebo, respectively. In IBS-D patients, the improvement from baseline of Bristol score was more consistent with LBB (from 6 ± 0.4 to 4.3 ± 1.1, P < .00001) than placebo (from 6.2 ± 0.7 to 5.3 ± 1.1, P = .04). In IBS-C patients, Bristol score tended to improve from baseline after LBB (2.6 ± 1.1 vs 3.2 ± 0.5, P = .06). LBB significantly improved the percentage of sucralose recovery (colonic permeability) (1.86 ± 0.1 vs 1.1 ± 0.2, P = .01). During treatment, presumptive lactic acid bacteria and bifidobacteria, relative abundance of propanoic, butanoic, pentanoic acids and hydrocarbons increased, while phenol decreased.

CONCLUSIONS

The novel formulation of B. longum BB536 and L. rhamnosus HN001 with B6 vitamin improves symptoms and severity of disease, restores intestinal permeability and gut microbiota in IBS patients.

Efficacy of prebiotics and probiotics for functional dyspepsia: A systematic review and meta-analysis

BACKGROUND

Functional dyspepsia (FD) is a functional gastrointestinal disorder. Evidence suggests that disturbance of the gastrointestinal microbiota may be implicated in FD. We performed a systematic review and meta-analysis to examine the efficacy of prebiotics and probiotics for FD.

METHODS

MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched (through September 2018). Randomized controlled trials (RCTs) that recruited adults with FD and that compared prebiotics, probiotics, or synbiotics with placebo or no therapy were eligible. Eligibility assessment and data extraction were performed by two independent researchers. Dichotomous symptom data were pooled to obtain a relative risk (RR) with a 95% confidence interval (CI) of remaining symptomatic after therapy. Continuous data were pooled using a standardized or weighted mean difference with a 95% CI.

RESULTS

The search strategy identified 1062 citations. Five RCTs were eligible for inclusion. The RR of FD symptoms improving with probiotics or probiotics vs placebo was 1.15 (95% CI 1.01-1.30). Probiotics and prebiotics had beneficial effects on symptom scores of FD. Data for synbiotics in the context of FD were sparse, and no definite conclusions could be drawn.

ETHICS AND DISSEMINATION

This study belongs to the category of systematic reviews, not clinical trials. Therefore, it does not require ethical approval. The results of this study will be published in influential international academic journals related to this topic.

CONCLUSION

Probiotics and prebiotics seemed to be effective treatments for FD, although the individual species and strains that are the most beneficial remain unclear. Using only probiotics failed to improve the symptoms of FD. Further evidence is required before the role of probiotics, prebiotics, and synbiotics in FD can be fully understood.

Probiotic Properties of Bacillus Strains Isolated from Stingless Bee (Heterotrigona itama) Honey Collected across Malaysia

This study aimed to isolate, identify, and evaluate the probiotic properties of Bacillus species from honey of the stingless bee Heterotrigona itama. Bacillus spp. were isolated from five different H. itama meliponicultures, and the isolates were characterized through Gram-staining and a catalase test. Tolerance to acidic conditions and bile salt (0.3%), hydrophobicity, and autoaggregation tests were performed to assess the probiotic properties of the selected isolates, B. amyloliquefaciens HTI-19 and B. subtilis HTI-23. Both Bacillus isolates exhibited excellent antimicrobial activity against both Gram-positive and Gram-negative bacteria and possessed significantly high survival rates in 0.3% bile solution for 3 h. Their survival rates in acidic conditions were also comparable to a commercial probiotic strain, Lactobacillus rhamnosus GG. Interestingly, the hydrophobicity and autoaggregation percentage showed no significant difference from L. rhamnosus GG, a commercial probiotic strain. The results from this study suggest that B. amyloliquefaciens HTI-19 and B. subtilis HTI-23 isolated from stingless bee honey have considerably good probiotic properties. Therefore, more studies should be done to investigate the effects of these bacteria cultures on gastrointestinal health.

Postbiotics: facts and open questions. A position paper on the need for a consensus definition

The past definitions of probiotics and prebiotics have been reviewed and updated recently. According to these concepts, probiotics comprise live microorganisms that confer a health benefit on the host when administered in adequate amounts, whereas a prebiotic is a substrate that is selectively utilised by host microorganisms, conferring a health benefit. The words probiotics and prebiotics can be found on labels of many foods and supplements. Consumers have a growing awareness of these terms' meanings, and many countries are increasingly using them for regulation purposes. At the same time, there is increasing evidence on the health effects of non-viable microorganisms and the metabolites that they can produce by fermentation or by their action on food components. Different terms have been used in the literature to refer to these bioactive compounds, which do not fall under the known categories of probiotics, prebiotics or synbiotics. The tentative term postbiotics has been the most used one so far. However, no definition of the term has gained international consensus to date. This work aims to provide information on the facts and the open questions about the so-called postbiotics.

Does Irritable Bowel Syndrome Exist? Identifiable and Treatable Causes of Associated Symptoms Suggest It May Not

Significant shortcomings in irritable bowel syndrome (IBS) diagnosis and treatment may arise from IBS being an “umbrella” diagnosis that clusters several underlying identifiable and treatable causes for the same symptom presentation into one classification. This view is compatible with the emerging understanding that the pathophysiology of IBS is heterogeneous with varied disease mechanisms responsible for the central pathological features. Collectively, these converging views of the pathophysiology, assessment and management of IBS render the traditional diagnosis and treatment of IBS less relevant; in fact, they suggest that IBS is not a disease entity per se and posit the question “does IBS exist?” The aim of this narrative review is to explore identifiable and treatable causes of digestive symptoms, including lifestyle, environmental and nutritional factors, as well as underlying functional imbalances, that may be misinterpreted as being IBS.

The role of inflammation and the gut microbiome in depression and anxiety

The study of the gut microbiome has increasingly revealed an important role in modulating brain function and mental health. In this review, we underscore specific pathways and mechanisms by which the gut microbiome can promote the development of mental disorders such as depression and anxiety. First, we review the involvement of the stress response and immune system activation in the development of depression and anxiety. Then, we examine germ-free murine models used to uncover the role of the gut microbiome in developing and modulating pertinent activity in the brain and the immune system. We also document multiple pathways by which stress-induced inflammation harms brain function and ultimately affects mental health, and review how probiotic and prebiotic treatments have shown to be beneficial. Lastly, we provide an overview of gut microbiome-derived compounds (short-chain fatty acids, tryptophan catabolites, microbial pattern recognition) and related mechanisms (vagal nerve activity and fecal microbiota transplants) involved in mediating the influence of the gut microbiome to mental health. Overall, a picture of the gut microbiome playing a facilitating role between stress response, inflammation, and depression, and anxiety is emerging. Future research is needed to firmly establish the microbiome's causal role, to further elucidate the mechanisms by which gut microbes influence brain function and mental health, and to possibly develop treatments that improve mental health through microbiotic targets.

Systematic review with meta-analysis: the efficacy of prebiotics, probiotics, synbiotics and antibiotics in irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a chronic functional bowel disorder. Disturbances in the gastrointestinal microbiome may be involved in its aetiology.

AIM

To perform a systematic review and meta-analysis to examine the efficacy of prebiotics, probiotics, synbiotics and antibiotics in IBS.

METHODS

MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched (up to July 2017). Randomised controlled trials (RCTs) recruiting adults with IBS, comparing prebiotics, probiotics, synbiotics or antibiotics with placebo or no therapy were eligible. Dichotomous symptom data were pooled to obtain a relative risk (RR) of remaining symptomatic after therapy, with a 95% confidence interval (CI). Continuous data were pooled using a standardised mean difference with a 95% CI.

RESULTS

The search identified 4017 citations. Data for prebiotics and synbiotics were sparse. Fifty-three RCTs of probiotics, involving 5545 patients, were eligible. Particular combinations of probiotics, or specific species and strains, appeared to have beneficial effects on global IBS symptoms and abdominal pain, but it was not possible to draw definitive conclusions about their efficacy. There were five trials of similar design that used rifaximin in non-constipated IBS patients, which was more effective than placebo (RR of symptoms persisting = 0.84; 95% CI 0.79-0.90). Adverse events were no more common with probiotics or antibiotics.

CONCLUSIONS

Which particular combination, species or strains of probiotics are effective for IBS remains, for the most part, unclear. Rifaximin has modest efficacy in improving symptoms in non-constipated IBS.

A Randomized Clinical Trial of Synbiotics in Irritable Bowel Syndrome: Dose-Dependent Effects on Gastrointestinal Symptoms and Fatigue

Background

This double-blind, randomized controlled design study aimed to assess the dose-dependent effects of synbiotics on gastrointestinal symptoms of and fatigue in irritable bowel syndrome (IBS).

Methods

Thirty subjects with IBS were randomly assigned into the following three groups and received 2 capsules a day for 8 weeks: (1) high-dose (2 capsules of synbiotics); (2) low-dose (1 capsule of synbiotics and 1 capsule of placebo); and (3) placebo (2 capsules of placebo). At baseline and 8 weeks, they completed the study questionnaires.

Results

Two subjects in the high-dose group were lost to follow-up, leaving a total of 28 patients for the analysis. After 8 weeks, abdominal discomfort, abdominal bloating, frequency of formed stool, fatigue Visual Analog Scale (VAS), and Multidimensional Fatigue Inventory were significantly different among the groups (P=0.002, 0.006, 0.007, 0.028, and 0.041, respectively, by Kruskal-Wallis test). However, only abdominal discomfort, abdominal bloating, frequency of formed stool, and fatigue VAS were significantly improved in the high-dose group compared with those in the placebo group (P=0.002, 0.003, 0.002, and 0.013, respectively) by Mann-Whitney test with Bonferroni correction. No adverse drug reactions were reported.

Conclusion

High-dose synbiotics were superior to placebo in improving bowel symptoms and fatigue of IBS patients, suggesting that synbiotic dosage plays an important role in the treatment of IBS.

Effects of an oral synbiotic on the gastrointestinal immune system and microbiota in patients with diarrhea-predominant irritable bowel syndrome

Purpose

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a common functional gastrointestinal disorder. Probiotics and synbiotics have been shown to improve symptoms of IBS, although mechanisms of action are currently not understood.

Methods

We investigated the effects of a 4-week oral synbiotic treatment (OMNi-BiOTiC^® Stress Repair) in ten IBS-D patients on gastrointestinal mucosal and fecal microbiota, mucosa-associated immune cells, and fecal short-chain fatty acids. The upper and lower gastrointestinal tracts were compared before and after a 4-week synbiotic treatment using endoscopic evaluation to collect mucosal specimens for FACS analysis and mucosal 16S rRNA gene analysis. In stool samples, analysis for fecal SCFAs using GC–MS, fecal zonulin using ELISA, and fecal 16S rRNA gene analysis was performed.

Results

Synbiotics led to an increased microbial diversity in gastric (p = 0.008) and duodenal (p = 0.025) mucosal specimens. FACS analysis of mucosal immune cells showed a treatment-induced reduction of CD4⁺ T cells (60 vs. 55%, p = 0.042) in the ascending colon. Short-chain fatty acids (acetate 101 vs. 202 µmol/g; p = 0.007) and butyrate (27 vs. 40 µmol/g; p = 0.037) were elevated in fecal samples after treatment. Furthermore, treatment was accompanied by a reduction of fecal zonulin concentration (67 vs. 36 ng/ml; p = 0.035) and disease severity measured by IBS-SSS (237 vs. 54; p = 0.002).

Conclusions

Our findings indicate that a short-course oral synbiotic trial may influence the human gastrointestinal tract in IBS-D patients on different levels which are region specific.

Electronic supplementary material

The online version of this article (10.1007/s00394-018-1826-7) contains supplementary material, which is available to authorized users.

Guidelines on the management of irritable bowel syndrome: In memory of Professor Witold Bartnik

These guidelines constitute an update of the previous "Recommendations on the management of irritable bowel syndrome" issued in 2008. They have been developed by a Task Force organized by the Governing Board of the Polish Society of Gastroenterology. They discuss, with particular emphasis on new scientific data covering papers published since 2008, the aetiology, epidemiology, clinical presentation, diagnostic principles and criteria for the diagnosis, and recommendations for the treatment of irritable bowel syndrome (IBS). The English-language acronym for the syndrome (IBS) has become popular in medical and popular scientific language. It is also widely recognized by patients who identify with this diagnosis. Therefore, in the discussed guidelines, this is what we will use.

Isolation of antibacterial protein from Lactobacillus spp. and preparation of probiotic curd

The study was aimed to isolate antagonistic lactobacilli and the molecules responsible for their antagonistic ability from curd. Preparation of probiotic curd and the ability of the selected lactobacilli to suppress the pathogen therein was also assessed. All the 116 isolates were identified as Lactobacillus spp. based on morphological, biochemical and curdling assays. Five of these lactobacilli (Lb-17, Lb-33, Lb-108, Lb-112, and Lb-N3) were found most promising to inhibit all test pathogens (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Salmonella typhi and Shigella sonnei). The cell-free culture supernatants of these five lactobacilli were recorded as thermo-tolerant when subjected to heat treatment at 100 °C for 20 min. The loss in the activity after protease treatment indicated the proteinaceous nature of the antimicrobial molecule present in the culture supernatants. Active protein (19 kDa) produced by lactobacilli was confirmed by SDS-PAGE followed by agar-overlay method. Antibiotic sensitivity assay revealed that the selected Lactobacillus spp. isolates were resistant to methicillin and vancomycin. Probiotic curd prepared by using Lb-108 and Lb-N3 was found to be superior to rest of the three isolates based on organoleptic tests and shelf-life. Complete inhibition of all the test pathogens in curd was shown by Lb-108 and Lb-N3. Inhibition spectrum, production of thermostable protein and preparation of quality curd suggest Lb-108 and Lb-N3 as promising candidates to prepare probiotic curd.