Strain-specific and outcome-specific efficacy of probiotics for the treatment of irritable bowel syndrome: A systematic review and meta-analysis

A novel probiotic formula, BLLL, ameliorates chronic stress-induced depression-like behaviors in mice by reducing neuroinflammation and increasing neurotrophic factors

Introduction: Probiotics have been recognized for their various biological activities, including antioxidant and anti-inflammatory properties. This study investigates the therapeutic effect of a novel probiotic formula, BLLL, consisting of Bifidobacterium breve, Lactobacillus plantarum, Lactobacillus paracasei, and Lactobacillus helveticus, on chronic stress-induced depression-like behaviors in mice. Methods: The BLLL formula or phosphate-buffered saline (PBS) was given orally at a dose of 2, 4, or 8 × 1010 CFU/kg once daily for 10 days in mice treated with chronic unpredictable stress (CUS) treated or vehicle. Depression-like behaviors were assessed using the sucrose preference test (SPT), the forced swimming test (FST), and the tail suspension test (TST). The mRNA and/or protein expression of interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), IL-4, IL-10, and chitinase-3-like protein 3 (CHI3L1, also known as Ym-1), as well as the concentration of nitrite, malondialdehyde (MDA), glutathione (GSH), and brain-derived neurotrophic factor (BDNF) in the hippocampus and medial prefrontal cortex were examined. Results: The BLLL formula treatment at a dose of 8 × 1010 CFU/kg, but not at a dose of 2 or 4 × 1010 CFU/kg, improved CUS-induced depression-like behaviors in mice, as shown by the decrease in immobility time in the TST and FST and the increase in sucrose intake in the SPT. Further analysis revealed that BLLL treatment suppressed the CUS-induced increase in IL-1β, IL-6, and TNF-α mRNA and protein levels, as well as the CUS-induced decrease in IL-4, IL-10, and Ym-1 mRNA and/or protein levels in the hippocampus and medial prefrontal cortex. In addition, treatment with the BLLL formula countered the CUS-induced increase in nitrite and MDA levels and the CUS-induced decrease in GSH content and BDNF concentration in the hippocampus and medial prefrontal cortex. Conclusion: These results demonstrate that the novel probiotic formula BLLL ameliorates chronic stress-induced depression-like behavior in mice by suppressing neuroinflammation and oxido-nitrosative stress in the brain.

Changes in Fecal Short-Chain Fatty Acids in IBS Patients and Effects of Different Interventions: A Systematic Review and Meta-Analysis

CONTEXT

Short-chain fatty acids (SCFAs) have been reported to be associated with the pathogenesis of irritable bowel syndrome (IBS), but the results are conflicting.

OBJECTIVE

Here, a systematic review of case-control studies detecting fecal SCFAs in IBS patients compared with healthy controls (HCs) and self-controlled studies or randomized controlled trials (RCTs) investigating fecal SCFA alterations after interventions were identified from several databases.

DATA SOURCES

A systematic search of databases (PubMed, Web of Science, and Embase) identified 21 studies published before 24 February 2023. Data extractions: Three independent reviewers completed the relevant data extraction.

DATA ANALYSIS

It was found that the fecal propionate concentration in IBS patients was significantly higher than that in HCs, while the acetate proportion was significantly lower. Low-FODMAP diets significantly reduced the fecal propionate concentration in the IBS patients while fecal microbiota transplantation and probiotic administration did not significantly change the fecal propionate concentration or acetate proportion.

CONCLUSIONS

The results suggested that the fecal propionate concentration and acetate proportion could be used as biomarkers for IBS diagnosis. A low-FODMAP diet intervention could potentially serve as a treatment for IBS while FMT and probiotic administration need more robust trials.

Gut microbiota and intestinal immunity-A crosstalk in irritable bowel syndrome

Irritable bowel syndrome (IBS), one of the most prevalent functional gastrointestinal disorders, is characterized by recurrent abdominal pain and abnormal defecation habits, resulting in a severe healthcare burden worldwide. The pathophysiological mechanisms of IBS are multi-factorially involved, including food antigens, visceral hypersensitivity reactions, and the brain-gut axis. Numerous studies have found that gut microbiota and intestinal mucosal immunity play an important role in the development of IBS in crosstalk with multiple mechanisms. Therefore, based on existing evidence, this paper elaborates that the damage and activation of intestinal mucosal immunity and the disturbance of gut microbiota are closely related to the progression of IBS. Combined with the application prospect, it also provides references for further in-depth exploration and clinical practice.

Collinsella aerofaciens as a predictive marker of response to probiotic treatment in non-constipated irritable bowel syndrome

Probiotics are exploited for adjuvant treatment in IBS, but reliable guidance for selecting the appropriate probiotic to adopt for different forms of IBS is lacking. We aimed to identify markers for recognizing non-constipated (NC) IBS patients that may show significant clinical improvements upon treatment with the probiotic strain Lacticaseibacillus paracasei DG (LDG). To this purpose, we performed a post-hoc analysis of samples collected during a multicenter, double-blind, parallel-group, placebo-controlled trial in which NC-IBS patients were randomized to receive at least 24 billion CFU LDG or placebo capsules b.i.d. for 12 weeks. The primary clinical endpoint was the composite response based on improved abdominal pain and fecal type. The fecal microbiome and serum markers of intestinal (PV1 and zonulin), liver, and kidney functions were investigated. We found that responders (R) in the probiotic arm (25%) differed from non-responders (NR) based on the abundance of 18 bacterial taxa, including the families Coriobacteriaceae, Dorea spp. and Collinsella aerofaciens, which were overrepresented in R patients. These taxa also distinguished R (but not NR) patients from healthy controls. Probiotic intervention significantly reduced the abundance of these bacteria in R, but not in NR. Analogous results emerged for C. aerofaciens from the analysis of data from a previous trial on IBS with the same probiotic. Finally, C. aerofaciens was positively correlated with the plasmalemmal vesicle associated protein-1 (PV-1) and the markers of liver function. In conclusion, LDG is effective on NC-IBS patients with NC-IBS with a greater abundance of potential pathobionts. Among these, C. aerofaciens has emerged as a potential predictor of probiotic efficacy.

Recommendations to Improve Quality of Probiotic Systematic Reviews With Meta-Analyses

Importance

Systematic reviews and meta-analyses often report conflicting results when assessing evidence for probiotic efficacy, partially because of the lack of understanding of the unique features of probiotic trials. As a consequence, clinical decisions on the use of probiotics have been confusing.

Objective

To provide recommendations to improve the quality and consistency of systematic reviews with meta-analyses on probiotics, so evidence-based clinical decisions can be made with more clarity.

Evidence Review

For this consensus statement, an updated literature review was conducted (January 1, 2020, to June 30, 2022) to supplement a previously published 2018 literature search to identify areas where probiotic systematic reviews with meta-analyses might be improved. An expert panel of 21 scientists and physicians with experience on writing and reviewing probiotic reviews and meta-analyses was convened and used a modified Delphi method to develop recommendations for future probiotic reviews.

Findings

A total of 206 systematic reviews with meta-analysis components on probiotics were screened and representative examples discussed to determine areas for improvement. The expert panel initially identified 36 items that were inconsistently reported or were considered important to consider in probiotic meta-analyses. Of these, a consensus was reached for 9 recommendations to improve the quality of future probiotic meta-analyses.

Conclusions and Relevance

In this study, the expert panel reached a consensus on 9 recommendations that should promote improved reporting of probiotic systematic reviews with meta-analyses and, thereby, assist in clinical decisions regarding the use of probiotics.

Probiotics for the management of irritable bowel syndrome: a systematic review and three-level meta-analysis

OBJECTIVE

Previous systematic reviews demonstrated a potentially beneficial effect of probiotics on irritable bowel syndrome (IBS). However, these studies are either affected by the inclusion of insufficient trials or by the problem of dependent data across multiple outcomes, and an overall effect size has not been provided. We aimed to determine the effect of probiotics on IBS through a three-level meta-analysis and clarify potential effect moderators.

METHODS

We searched MEDLINE, Embase, and Web of Science, screening for randomized controlled trials (RCTs) that examine the effect of probiotics on IBS. The primary outcome was the improvement in the severity of global IBS symptoms at the end of treatment. The secondary outcomes were the improvement in abdominal pain and the quality of life. The effect sizes of the probiotics were measured by using the standardized mean difference (SMD) and pooled by a three-level meta-analysis model.

RESULTS

We included 72 RCTs in the analysis. The meta-analysis showed significantly better overall effect of probiotics than placebo on the global IBS symptoms (SMD -0.55, 95% CI -0.76 to -0.34, P <0.001), abdominal pain (SMD -0.89, 95% CI -1.29 to -0.5, P <0.001) and quality of life (SMD 0.99, 95% CI 0.45 to 1.54, P <0.001), respectively. Moderator analysis found that a treatment duration shorter than 4 weeks was associated with a larger effect size in all the outcomes, and Bacillus probiotics had better improvement on the abdominal pain.

CONCLUSIONS

Probiotics had a short-term effect and a medium effect size on the global IBS symptoms. Treatment duration and types of probiotics affected the effect size of probiotics, and shorter durations and Bacillus probiotics were associated with better treatment effects.

REGISTRATION

Open Science Framework.

Species- or genus-dependent immunostimulatory effects of gut-derived potential probiotics

The immune regulatory effects of probiotics have been widely recognized to be strain-specific. However, it is unknown if there is a species- or genus-dependent manner. In this study, we use an in vitro mesenteric lymph node (MLN) model to systematically evaluate the immunostimulatory effects of gut-derived potential probiotics. The results exhibit an obvious species or genus consensus immune response pattern. RNA-seq shows that T cell-dependent B cell activation and antibody responses may be inherent to this model. Of the five tested genera, Akkermansia spp. and Clostridium butyrium directly activate the immune response in vitro, as indicated by the secretion of interleukin-10. Bifidobacterium spp. and Bacteroides spp. activate immune response with the help of stimuli (anti-CD3 and anti-CD28 antibodies). Lactobacillus spp. blunt the immune response with or without stimuli. Further investigations show that the cell surface protein of A. muciniphila AH39, which may serve as a T cell receptor cognate antigen, might evoke an in vitro immune activation. In vivo, oral administration of A. muciniphila AH39 influences the proportion of T regulatory cells (Tregs) in MLNs and the spleen under homeostasis in both specific pathogen-free and germ-free mice. All these findings indicate the distinct effects of different genera or species of potential gut-derived probiotics on intestinal and systemic immunity.

A Novel Nutrient Intervention of Probiotics, Glutamine, and Fish Oil in Psychological Distress: A Concurrent Multiple Baseline Design

Objectives: The aim of this study was to investigate whether a combination of nutrients designed to promote gut and brain health also lowers psychological distress. The hypothesis is that a probiotic with fish oil, and glutamine supplement will reduce psychological distress. Design: A multiple baseline design was used to collect data from seven naturopathic patients in private naturopathic clinics in Australia. Patients were between 18 and 65 years of age, and had a Kessler-10 (K10) score between 16 and 30 and symptoms associated with mild gastrointestinal discomfort experienced several times most weeks for 3 months. They were randomized into one of three pathways to stagger the introduction of the intervention. Interventions: Participants received either a supplement incorporating a probiotic formulation (including Lactobacillus rhamnosus), a glutamine powder formulation, and fish oil, or matched placebos. The primary outcome measure was psychological distress as measured by the K10 scale of psychological distress. Results: The data showed a general trend toward lower K10 scores during the active phase compared with the baseline phase, with a marked reduction in the variances between phases. After controlling for time and baseline values, no significant difference between the phases for the K10 and the Perceived Stress Scale was found, but there was still a significant reduction in symptoms on the Gastrointestinal Symptom Rating Scale. Conclusions: A combination of a probiotic formulation, a glutamine powder formulation, and fish oil did not affect psychological distress and perceived stress, but had a significant beneficial effect on gastrointestinal symptoms in patients with high distress and concurrent gut symptomology. Clinical trial registration number: ACTRN12620000928910.

Gut Dysbiosis in Irritable Bowel Syndrome: A Narrative Review on Correlation with Disease Subtypes and Novel Therapeutic Implications

Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal disorder characterized by chronic abdominal pain and altered bowel habits. It can be subclassified in different subtypes according to the main clinical manifestation: constipation, diarrhea, mixed, and unclassified. Over the past decade, the role of gut microbiota in IBS has garnered significant attention in the scientific community. Emerging research spotlights the intricate involvement of microbiota dysbiosis in IBS pathogenesis. Studies have demonstrated reduced microbial diversity and stability and specific microbial alterations for each disease subgroup. Microbiota-targeted treatments, such as antibiotics, probiotics, prebiotics, synbiotics, fecal microbiota transplantation, and even diet, offer exciting prospects for managing IBS. However, definitive conclusions are hindered by the heterogeneity of these studies. Further research should focus on elucidating the mechanisms, developing microbiome-based diagnostics, and enabling personalized therapies tailored to an individual's microbiome profile. This review takes a deep dive into the microscopic world inhabiting our guts, and its implications for IBS. Our aim is to elucidate the complex interplay between gut microbiota and each IBS subtype, exploring novel microbiota-targeted treatments and providing a comprehensive overview of the current state of knowledge.

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.

The Rationale for Sulforaphane Favourably Influencing Gut Homeostasis and Gut-Organ Dysfunction: A Clinician's Hypothesis

Given the increasing scientific, clinical and consumer interest in highly prevalent functional gastrointestinal disorders, appropriate therapeutic strategies are needed to address the many aspects of digestive dysfunction. Accumulating evidence for the crucifer-derived bioactive molecule sulforaphane in upstream cellular defence mechanisms highlights its potential as a therapeutic candidate in targeting functional gastrointestinal conditions, as well as systemic disorders. This article catalogues the evolution of and rationale for a hypothesis that multifunctional sulforaphane can be utilised as the initial step in restoring the ecology of the gut ecosystem; it can do this primarily by targeting the functions of intestinal epithelial cells. A growing body of work has identified the colonocyte as the driver of dysbiosis, such that targeting gut epithelial function could provide an alternative to targeting the microbes themselves for the remediation of microbial dysbiosis. The hypothesis discussed herein has evolved over several years and is supported by case studies showing the application of sulforaphane in gastrointestinal disorders, related food intolerance, and several systemic conditions. To the best of our knowledge, this is the first time the effects of sulforaphane have been reported in a clinical environment, with several of its key properties within the gut ecosystem appearing to be related to its nutrigenomic effects on gene expression.

Efficacy and dose response of Lactiplantibacillus plantarum in diarrhea-predominant irritable bowel syndrome

BACKGROUND

Probiotics have shown promise in alleviating symptoms of diarrhea-predominant irritable bowel syndrome (IBS-D); however, the certainty of evidence is low. Well-powered randomized controlled dose-ranging trials are warranted on promising single-strain candidates.

AIM

To investigate the clinical efficacy of Lactiplantibacillus plantarum (L. plantarum) Lpla33 (DSM34428) in adults with IBS-D.

METHODS

This is a randomized, double-blind, placebo-controlled, multi-center, and dose-ranging study. Three hundred and seven adults, 18-70 years of age, with IBS-D, according to Rome IV criteria, were allocated (1:1:1) to receive placebo or L. plantarum Lpla33 at 1 × 109 (1B) or 1 × 1010 (10B) colony-forming units/d over an 8-wk intervention period. The primary outcome was the change in IBS severity scoring system (IBS-SSS) total score after 8 wk, while secondary and exploratory outcomes included abdominal pain severity, IBS related quality of life, stool and microbial profile, and perceived stress.

RESULTS

IBS-SSS was significantly reduced, after 8 wk, in participants receiving L. plantarum 1B (-128.45 ± 83.30; P < 0.001) and L. plantarum 10B (-156.77 ± 99.06; P < 0.001), compared to placebo (-58.82 ± 74.75). Further, a dose-ranging effect was observed, with a greater absolute reduction in the L. plantarum 10B group (P < 0.05). A reduction in sub-scores related to abdominal pain, abdominal distension, bowel habits, and quality of life was observed in both L. plantarum groups compared to placebo (P < 0.001). Further, 62.5% and 88.4% of participants administered L. plantarum 1B and 10B, respectively, were classified as stool consistency responders based on a reduction in diarrheal stool form, as compared to 26.3% in the placebo group (P < 0.001). In contrast, no significant shifts were observed in microbial diversity.

CONCLUSION

L. plantarum Lpla33 (DSM34428) is well tolerated and improves IBS symptom severity with a dose-ranging effect and a corresponding normalization of bowel habits in adults with IBS-D.

Effect of a probiotic formula on gastrointestinal health, immune responses and metabolic health in adults with functional constipation or functional diarrhea

Objective

Our aim was to determine the efficacy of four-week probiotic supplementation on gastrointestinal health. The secondary objectives were to assess probiotic effects on immune reaction, as well as weight control and metabolic health.

Methods

We conducted two randomized sub-trials, respectively, among subjects who were diagnosed with functional constipation (FC) or functional diarrhea (FDr) according to the Rome IV criteria. In each sub-trial, 70 eligible Chinese adults were randomized to receive a multi-strain probiotic combination or a placebo. Gastrointestinal symptoms, defecation habits, stool characteristics, blood and fecal biochemistry markers, anthropometrics measures, stress-associated responses, and intestinal flora changes were assessed at baseline and after probiotics intervention.

Results

Four weeks of probiotic supplementation reduced overall gastrointestinal symptoms scores in FC participants (p < 0.0001). Their mean weekly stool frequency increased from 3.3 times to 6.2 times; immune response and inflammation markers improved with increases in serum IgA, IFN-γ and fecal sIgA, and decrease in hsCRP; most components of lipid profile were significantly ameliorated, with increases in HDL-C and reductions in TC and TG; body weight, body mass index and basal metabolic rate decreased following probiotics consumption. For FDr participants, probiotics consumption markedly reduced overall gastrointestinal symptom scores (p < 0.0001); decreased stool frequency by 3 times per week; increased IgA, IFN-γ, sIgA concentrations, while lowered hsCRP and IL-4 levels. Both FC and FDr participants had improvement in the scores of defecation habits, anxiety or depression, and perceived stress. Probiotics supplementation promoted the production of all three major short-chain fatty acids. No changes were observed in LDL-C, IgG, IgM, IL-8, IL-10 and motilin.

Conclusion

Supplementation with the probiotic formula over a four-week period could help relieving gastrointestinal symptoms, improving satisfaction with defecation habits, emotional state and immune response, and ameliorating dysbacteriosis in participants with FC or FDr. It also had beneficial effects on lipid metabolism and weight control for FC participants.

Update on treatment of abdominal pain in irritable bowel syndrome: A narrative review

The objectives of this narrative review are to update readers on the current state-of-the-art regarding diverse approaches for the treatment of pain, global symptoms, or adequate relief in irritable bowel syndrome (IBS). The article appraises medications, dietary interventions including low fermentable oligosaccharides, disaccharides, and monosaccharides and polyols (FODMAP) diet, fecal microbial transplantation (FMT), electrical approaches, and behavioral therapies including cognitive behavioral therapy (CBT), gut-directed hypnotherapy (GDH), mindfulness, and open-label placebo. Current evidence demonstrates only modest benefit in global IBS symptoms and pain relief. A future approach that identifies pathophysiological mechanisms of IBS through validated biomarkers has the potential to individualize treatment of patients rather than sequential therapeutic trial and error approaches.

Probiotics in irritable bowel syndrome and inflammatory bowel disease: review of mechanisms and effectiveness

PURPOSE OF REVIEW

The gastrointestinal (GI) microbiome has been implicated in the pathogenesis of inflammatory bowel disease (IBD) and has been linked with irritable bowel syndrome (IBS). The aim of this article is to critically review the emerging evidence for the mechanisms and effectiveness of probiotics in the management of these conditions.

RECENT FINDINGS

The GI microbiome is strongly influenced by ageing, diet and disease. Probiotics may confer health effects to the host by modulating the metabolic activities of the microbiome to propagate anti-inflammatory effects and reinforce the intestinal barrier, and are considered to be safe to use. Many short-term studies have demonstrated the effectiveness of probiotics overall in IBS, with meta-analyses demonstrating efficacy across specific strains albeit with relatively small effect sizes. Within IBD, some probiotics appear to offer clinical benefit in ulcerative colitis but strain-specific effects are unclear. Evidence for the use of probiotics in Crohn's disease remains limited.

SUMMARY

Probiotics offer considerable potential for the management of IBS and possibly in IBD, however, any benefits conferred appear to be strain-specific. High quality trials of specific probiotics in IBS and IBD, as well as laboratory investigations of their mechanism of action, are required in order to fully understand their potential therapeutic value.

MRSA compendium of epidemiology, transmission, pathophysiology, treatment, and prevention within one health framework

Staphylococcus aureus is recognized as commensal as well as opportunistic pathogen of humans and animals. Methicillin resistant strain of S. aureus (MRSA) has emerged as a major pathogen in hospitals, community and veterinary settings that compromises the public health and livestock production. MRSA basically emerged from MSSA after acquiring SCCmec element through gene transfer containing mecA gene responsible for encoding PBP-2α. This protein renders the MRSA resistant to most of the β-lactam antibiotics. Due to the continuous increasing prevalence and transmission of MRSA in hospitals, community and veterinary settings posing a major threat to public health. Furthermore, high pathogenicity of MRSA due to a number of virulence factors produced by S. aureus along with antibiotic resistance help to breach the immunity of host and responsible for causing severe infections in humans and animals. The clinical manifestations of MRSA consist of skin and soft tissues infection to bacteremia, septicemia, toxic shock, and scalded skin syndrome. Moreover, due to the increasing resistance of MRSA to number of antibiotics, there is need to approach alternatives ways to overcome economic as well as human losses. This review is going to discuss various aspects of MRSA starting from emergence, transmission, epidemiology, pathophysiology, disease patterns in hosts, novel treatment, and control strategies.

Fungal feelings in the irritable bowel syndrome: the intestinal mycobiome and abdominal pain

Although the gut microbiota consists of bacteria, viruses, and fungi, most publications addressing the microbiota-gut-brain axis in irritable bowel syndrome (IBS) have a sole focus on bacteria. This may relate to the relatively low presence of fungi and viruses as compared to bacteria. Yet, in the field of inflammatory bowel disease research, the publication of several papers addressing the role of the intestinal mycobiome now suggested that these low numbers do not necessarily translate to irrelevance. In this review, we discuss the available clinical and preclinical IBS mycobiome data, and speculate how these recent findings may relate to earlier observations in IBS. By surveying literature from the broader mycobiome research field, we identified questions open to future IBS-oriented investigations.

Non-pharmacological strategies to treat irritable bowel syndrome: 2022 update

Irritable bowel syndrome (IBS) is a chronic functional disorder characterized by abdominal pain associated with changes in stool frequency or form, in absence of organic disease. The treatment of IBS is often challenging and should be individually adjusted according to the prevalent symptomatology. Pharmacological treatment for IBS with diarrhea includes peripheral opioid agonists, bile acid sequestrants and antibiotics, while IBS with constipation can be treated with soluble fibers, osmotic agents or prokinetics. In case of abdominal pain, the available pharmacological options are antispasmodics, peripheral opioid agonists or antidepressants. Along with pharmacotherapy, non-pharmacological interventions should be considered as they can play an important role in symptom control. The first-line approach includes lifestyle modifications and dietary advice. Microbiota manipulation through probiotics, prebiotics and symbiotics is a widely used strategy, although the evidence upon the most effective among these in specific IBS subtypes is still unclear. Fecal microbiota transplantation is still in experimental phase for IBS, but it is giving promising results. Psychological therapies may be effective in patients with IBS, despite their application can be limited by long duration, high costs and poor patient's acceptance. Alternative medicine approaches, such as acupuncture, body relaxation techniques, dietary supplements or Chinese herbs, have been proposed; however, the evidence upon their efficacy and safety is still controversial.

Recognizing the role of the vagus nerve in depression from microbiota-gut brain axis

Depression is a worldwide disease causing severe disability, morbidity, and mortality. Despite abundant studies, the precise mechanisms underlying the pathophysiology of depression remain elusive. Recently, cumulate research suggests that a disturbance of microbiota-gut-brain axis may play a vital role in the etiology of depression while correcting this disturbance could alleviate depression symptoms. The vagus nerve, linking brain and gut through its afferent and efferent branches, is a critical route in the bidirectional communication of this axis. Directly or indirectly, the vagus afferent fibers can sense and relay gut microbiota signals to the brain and induce brain disorders including depression. Also, brain changes in response to stress may result in gut hyperpermeability and inflammation mediating by the vagal efferents, which may be detrimental to depression. Notably, vagus nerve stimulation owns an anti-inflammatory effect and was proved for depression treatment. Nevertheless, depression was accompanied by a low vagal tone, which may derive from response to stress and contribute to pathogenesis of depression. In this review, we aim to explore the role of the vagus nerve in depression from the perspective of the microbiota-gut-brain axis, highlighting the relationship among the vagal tone, the gut hyperpermeability, inflammation, and depression.

Treatments targeting the luminal gut microbiota in patients with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction affecting 4% of the world's population. Patients with IBS experience chronic or recurrent abdominal pain in combination with altered bowel habits (diarrhea and/or constipation), and have reduced quality of life. Despite the high prevalence and substantial burden of IBS, its pathophysiology is incompletely understood and remains to be elucidated. The importance of the gut microenvironment has been highlighted in IBS, as there are signs that the gut microbiota of patients differs from healthy controls. Recent studies have aimed to alter the gut microbiota and thereby, attempted to alleviate gastrointestinal symptoms in IBS patients. We highlighted recent advances in common treatments that are targeting the luminal gut microbiota in IBS.

Probiotics in the Management of Mental and Gastrointestinal Post-COVID Symptomes

Patients with “post-COVID” syndrome manifest with a variety of signs and symptoms that continue/develop after acute COVID-19. Among the most common are gastrointestinal (GI) and mental symptoms. The reason for symptom occurrence lies in the SARS-CoV-2 capability of binding to exact receptors, among other angiotensin converting enzyme 2 (ACE2) receptors in gastrointestinal lining and neuropilin-1 (NRP-1) in the nervous system, which leads to loss of gastrointestinal and blood-brain barriers integrity and function. The data are mounting that SARS-CoV-2 can trigger systemic inflammation and lead to disruption of gut-brain axis (GBA) and the development of disorders of gut brain interaction (DGBIs). Functional dyspepsia (FD) and irritable bowel syndrome (IBS) are the most common DGBIs syndromes. On the other hand, emotional disorders have also been demonstrated as DGBIs. Currently, there are no official recommendations or recommended procedures for the use of probiotics in patients with COVID-19. However, it can be assumed that many doctors, pharmacists, and patients will want to use a probiotic in the treatment of this disease. In such cases, strains with documented activity should be used. There is a constant need to plan and conduct new trials on the role of probiotics and verify their clinical efficacy for counteracting the negative consequences of COVID-19 pandemic. Quality control is another important but often neglected aspect in trials utilizing probiotics in various clinical entities. It determines the safety and efficacy of probiotics, which is of utmost importance in patients with post-acute COVID-19 syndrome.

Saccharomyces cerevisiae I-3856 in irritable bowel syndrome with predominant constipation

BACKGROUND

Probiotics are a promising solution for managing irritable bowel syndrome (IBS). Saccharomyces cerevisiae (S. cerevisiae) I-3856 has already demonstrated beneficial effects in IBS subjects, particularly in IBS with predominant constipation (IBS-C).

AIM

To confirm the efficacy of S. cerevisiae I-3856 in the management of gastrointestinal symptoms in IBS-C.

METHODS

A randomized, double-blind, placebo-controlled clinical study was performed in a total of 456 subjects. After a run-in period, subjects were randomly assigned to the group receiving S. cerevisiae I-3856 (8 × 10⁹ CFU daily) or the placebo for 8 wk, and they performed daily self-evaluations of gastrointestinal symptoms. The primary objective was to assess the effect of the probiotic on abdominal pain. The secondary objectives were the evaluation of other gastrointestinal symptoms, bowel movement frequency and consistency, and quality of life (QOL).

RESULTS

A significantly higher proportion of abdominal pain responders was reported in the Probiotic group (45.1% vs 33.9%, P = 0.017). A nonsignificant difference in the area under the curve for abdominal pain over the second month of supplementation was observed in subjects receiving probiotic vs placebo [P = 0.073, 95%CI: -0.59 (-1.23; 0.05)]. No statistically significant differences were reported in the evolution of bowel movement frequency and stool consistency between the groups. After 8 wk of supplementation, the overall QOL score was significantly higher in the Probiotic group than in the Placebo group [P = 0.047, 95%CI: 3.86 (0.52; 7.20)]. Furthermore, exploratory analyses showed statistically significant and clinically relevant improvements in QOL scores in abdominal pain responders vs nonresponders.

CONCLUSION

The results of this clinical study confirmed the abdominal pain alleviation properties of S. cerevisiae I-3856 in IBS-C. Abdominal pain relief was associated with improved QOL. ClinicalTrials.gov identifier: NCT03150212.

Determination of Probiotics Prescription Indications in Patients with Irritable Bowel Syndrome (Materials of the Expert Council and Literature Review)

Aim. To review the main indications for probiotics prescription in patients with irritable bowel syndrome and to present the materials of an Expert Council, which was held on 18 March 2022 in Moscow.

Key points. Gut microbiota disturbance is an integral part of irritable bowel syndrome (IBS) pathogenesis. Changes of colonic microbiota composition are associated with its functional potential modification, which leads to an increasing of the pro-inflammatory immune response, as well as to an exacerbation of the disease symptoms and quality of life decreasing in patients with IBS. The novel coronavirus infection (COVID-19) is an independent risk factor for both exacerbation and onset of IBS, which predispose to increase IBS incidence. Correction of gut microbiota composition with probiotics seems to be a promising therapeutic target for IBS treatment optimizing. The optimal probiotic should be effective, safe, strain-specific, and its dose and duration of administration should be confirmed by the results of clinical studies. Some of the probiotics with proven efficacy in IBS are Alflorex® and Enterol®.

Conclusion. Prescription of certain probiotics in IBS is advisable to normalize the frequency and consistency of stools, relieve abdominal pain and bloating, as well as improve patients’ quality of life.

Gut–Skin Axis: Unravelling the Connection between the Gut Microbiome and Psoriasis

Evidence has shown that gut microbiome plays a role in modulating the development of diseases beyond the gastrointestinal tract, including skin disorders such as psoriasis. The gut–skin axis refers to the bidirectional relationship between the gut microbiome and skin health. This is regulated through several mechanisms such as inflammatory mediators and the immune system. Dysregulation of microbiota has been seen in numerous inflammatory skin conditions such as atopic dermatitis, rosacea, and psoriasis. Understanding how gut microbiome are involved in regulating skin health may lead to development of novel therapies for these skin disorders through microbiome modulation, in particularly psoriasis. In this review, we will compare the microbiota between psoriasis patients and healthy control, explain the concept of gut–skin axis and the effects of gut dysbiosis on skin physiology. We will also review the current evidence on modulating gut microbiome using probiotics in psoriasis.

Administration of probiotics to healthy volunteers: effects on reactivity of intestinal mucosa and systemic leukocytes

Background

Oral administration of health-promoting bacteria is increasingly used in clinical practise. These bacteria have anti-inflammatory characteristics and modulate the immune system without major reported side effects. The mechanisms of action are not yet fully defined. Our aim was to study systemic effects of probiotics by measurements of leukocytes as well as local effects on rectal mucosal biopsies after adding a standardized inflammatory stimulus in vitro.

Methods

Fourteen healthy subjects were randomized to receive 10¹⁰ colony forming units/day orally of the probiotic strain Lactiplantibacillus plantarum 299 (Lp299), n = 7, or Bifidobacterium infantis CURE21 (CURE21), n = 7, for six weeks. Rectal biopsies were taken before and after ingestion of either probiotic strain product, for stimulation in vitro with tumour necrosis factor alpha (TNF-α) at 10 and 100 ng/ml respectively up to 8 h. Blood tests were sampled before and after treatment. Lactate dehydrogenase (LDH) confirmed viable tissue.

Results

Composition of the intestinal microbiota was not changed. Systemic leukocytes decreased after administration of CURE21 (P<0.05) and Lp299 (P<0.01). Levels of the pro-inflammatory cytokine IL-6 in rectal mucosa after stimulation with TNF-α were attenuated after ingestion of Lp299. No effect was seen with CURE21.

Conclusions

Administration of these probiotic strains to healthy humans show both a systemic and local reduction of inflammatory response by lowering leukocyte counts, and for Lp299 IL-6 levels in rectal mucosa. Probiotics may play an important role in the reduction of inflammatory responses expected after trauma during surgery or after pelvic irradiation.

Trial registration Clinical Trials, registration number NCT01534572, retrospectively registered (http://www.clinicaltrials.gov).

Pain in irritable bowel syndrome: Does anything really help?

Pain relief remains a significant challenge in the management of irritable bowel syndrome (IBS): "Does anything really help relieve the pain in patients with IBS?". Interventions aimed at pain relief in patients with IBS include diet, probiotics or antibiotics, antidepressants, antispasmodics, and drugs targeting specific gastrointestinal receptors such as opioid or histamine receptors. In the systematic review and meta-analysis published in this journal, Lambarth et al. examined the literature on the role of oral and parenteral anti-neuropathic agents in the management of pain in patients with IBS. This review article appraises their assessment of the efficacy of the anti-neuropathic agents amitriptyline, pregabalin, gabapentin, and duloxetine in the relief of abdominal pain or discomfort, and impact on overall IBS severity and quality of life. This commentary provides an update of current evidence on the efficacy of the dietary and pharmacological treatments that are available or in development, as well psychological and cognitive behavioral therapy for pain in IBS. Advances in recent years augur well for efficacious treatments that may expand the therapeutic arsenal for pain in IBS.

Probiotics in irritable bowel syndrome - is the quest for the right strain over? Rapid review of existing guidelines and recommendations

Irritable bowel syndrome (IBS) - functional gastrointestinal disorder (FGIDs) and disorder of gut-brain interaction (DGBIs) - has emerged as an important medical problem with an impact on health care systems, affecting patients' quality of life. The management of IBS consists of pharmacological and non-pharmacological treatments; however, the data of their long-term efficacy are scarce. Modulation of gastrointestinal microbiota, by means of probiotics and prebiotics, is often sought and advertised as a popular treatment modality in IBS. Faecal microbiota transplantation (FMT) awaits recommendations for IBS treatment and requires more methodological assessments. To date, numerous guidelines and recommendations have been published on the role of probiotics in IBS. Because no probiotic claim for probiotics in foods has yet been granted by the European Food and Safety Authority (EFSA), medical practitioners still recommend probiotics on the basis of available literature and recommendations released by independent health authorities. We aimed to summarize published formal recommendations and guidelines regarding the clinical effectiveness of available probiotic strains and conduct a random-effects meta-analysis of outcomes for which ≥ 2 studies contributed data on the same probiotic strain recommended to adults with IBS. Based on available and most recent guidelines, we report that probiotics, as a group, may be an effective treatment for global symptoms and abdominal pain in IBS, with the strongest effect for genus Lactobacillus. Our current and updated meta-analysis is in line with several reports documenting significant effects of Lactobacillus plantarum (Lp299v) in reducing the risk of global symptoms and their persistence, which could assist clinicians in making the choice for the right probiotic strain in IBS patients.