A medical and molecular approach to kefir as a therapeutic agent of human microbiota

The imbalanced microbial composition called dysbiosis constitutes a tendency related to different kind of human diseases. To overcome the disadvantages of dysbiosis, the consumption of probiotics is an emerging and promising topic of the last decade. Kefir is a probiotic fermented beverage produced from the fermentation of kefir grains with changing varieties of milk and displays a symbiotic association of bacteria and yeast. The discovery of the concept that fermented foods/beverages such as kefir could modify gut microbiota in humans has widened the borders of precision medicine and now microbiome therapeutics can be considered as a significant part of this field. Kefir seems to have potential to guide and manipulate future replacement/complementary therapies with a variety of beneficial biological/medical properties it has. The aim of this review was a comprehensive recapitulation of probiotic beverage kefir's significant properties mainly focusing of antioxidative, immunomodulatory, apoptotic, antitumor and neuroprotective properties. Apoptotic/antimetastatic effects are regulated at the molecular level by increases in TGF-β1, caspase-3, p53, Bax, Bax:Bcl-2 ratio, p21 and decreases in TGF-α, Bcl-2 and MMP polarization. Neuroprotective effects are revealed upon upregulation of SOD/catalase and anti-inflammatory Treg cells, decreases in repetitive behavior and modulation of apoptotic genes. Besides these significant features that may offer advantages in supplementary cancer therapies, the scope was also extended to recent emerging medical topics and also discussed and evaluated the concept of "psychobiotics". The therapeutic potential of psychobiotic effect is majorly attributed to the increased ratios of Clostridium butyricum, Lactobacillus and Bifidobacterium.

Evaluation of GABA Production by Alginate-Microencapsulated Fresh and Freeze-Dried Bacteria Enriched with Monosodium Glutamate during Storage in Chocolate Milk

Two strains of γ-aminobutyric acid (GABA) producing bacteria, L. brevis Y1 and L. plantarum LM2, were microencapsulated in sodium alginate with two concentrations (1% and 2%) of monosodium glutamate (MSG) by using vibrating technology. The mix of both species was microencapsulated both in fresh and freeze-dried form. After 0, 1, 2, and 4 weeks of storage at 4 °C in quarter strength Ringer's solution, the microcapsules were subjected to cell viable counting and sub-cultured in MRS at 37° for 24 h. The MRS cultures were analyzed for the GABA content. The amount of GABA produced per CFU of MRS inoculum was then calculated. Only the 4-week-old microcapsules were used to inoculate a chocolate milk drink with the aim of obtaining a functionalized drink containing viable probiotic cells and GABA after a 1-week incubation at 4 °C. Therefore, the GABA production in chocolate milk per CFU of the probiotic culture after the incubation time was calculated. Results of the GABA analysis by liquid chromatography mass spectrometry of the MRS sub-cultures showed no significant difference (p > 0.05) in GABA yield between 1% and 2% MSG for the microcapsules containing fresh cells. On the contrary, a significant difference (p < 0.05) in productivity along the storage was registered. Microcapsules containing freeze-dried cells showed significant differences (p < 0.05) in GABA yield between 1% and 2% MSG only after 2 and 4 weeks of storage. A significant difference (p < 0.05) in GABA yield between the storage time was found only for the trials with 2% MSG for freeze-dried cells. The synthesis of GABA in chocolate milk significantly decreased (p < 0.05) only for fresh cells when comparing 2% with 1% MSG. In conclusion, a 1-month storage of microcapsules containing both culture forms, fresh and freeze-dried, did not affect GABA production.

Exploring the Potential of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 as Promising Psychobiotics Using SHIME

Psychobiotics are probiotics that have the characteristics of modulating central nervous system (CNS) functions or reconciled actions by the gut-brain axis (GBA) through neural, humoral and metabolic pathways to improve gastrointestinal activity as well as anxiolytic and even antidepressant abilities. The aim of this work was to evaluate the effect of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 on the gut microbiota of mildly anxious adults using SHIME^®. The protocol included a one-week control period and two weeks of treatment with L. helveticus R0052 and B. longum R0175. Ammonia (NH4+), short chain fatty acids (SCFAs), gamma-aminobutyric acid (GABA), cytokines and microbiota composition were determined. Probiotic strains decreased significantly throughout the gastric phase. The highest survival rates were exhibited by L. helveticus R0052 (81.58%; 77.22%) after the gastric and intestinal phase when compared to B. longum (68.80%; 64.64%). At the genus level, a taxonomic assignment performed in the ascending colon in the SHIME^® model showed that probiotics (7 and 14 days) significantly (p < 0.005) increased the abundance of Lactobacillus and Olsenella and significantly decreased Lachnospira and Escheria-Shigella. The probiotic treatment (7 and 14 days) decreased (p < 0.001) NH₄⁺ production when compared to the control period. For SCFAs, we observed after probiotic treatment (14 days) an increase (p < 0.001) in acetic acid production and total SCFAs when compared to the control period. Probiotic treatment increased (p < 0.001) the secretion of anti-inflammatory (IL-6 and IL-10) and decreased (p < 0.001) pro-inflammatory cytokines (TNF-alpha) when compared to the control period. The gut-brain axis plays an important role in the gut microbiota, producing SCFAs and GABA, stimulating the production of anti-anxiety homeostasis. The signature of the microbiota in anxiety disorders provides a promising direction for the prevention of mental illness and opens a new perspective for using the psychobiotic as a main actor of therapeutic targets.

Exposure to Antibiotics and Neurodevelopmental Disorders: Could Probiotics Modulate the Gut-Brain Axis?

In order to develop properly, the brain requires the intricate interconnection of genetic factors and pre-and postnatal environmental events. The gut-brain axis has recently raised considerable interest for its involvement in regulating the development and functioning of the brain. Consequently, alterations in the gut microbiota composition, due to antibiotic administration, could favor the onset of neurodevelopmental disorders. Literature data suggest that the modulation of gut microbiota is often altered in individuals affected by neurodevelopmental disorders. It has been shown in animal studies that metabolites released by an imbalanced gut-brain axis, leads to alterations in brain function and deficits in social behavior. Here, we report the potential effects of antibiotic administration, before and after birth, in relation to the risk of developing neurodevelopmental disorders. We also review the potential role of probiotics in treating gastrointestinal disorders associated with gut dysbiosis after antibiotic administration, and their possible effect in ameliorating neurodevelopmental disorder symptoms.

Ingestion of Lactobacillus helveticus WHH1889 improves depressive and anxiety symptoms induced by chronic unpredictable mild stress in mice

Emerging evidence indicates that the alterations in the gut microbiota-brain axis (GBA), which is the bilateral connection between the gut microbial communities and brain function, are involved in several mental illnesses, including depression. Certain probiotic strains have been revealed to improve depressive behaviours and the dysregulation of 5-hydroxytryptamine (5-HT) metabolism in depression. Here we evaluated the potential antidepressant effects of Lactobacillus helveticus strains using an in vitro enterochromaffin cell model (RIN14B). The L. helveticus strain WHH1889 was shown to significantly promote the level of 5-hydroxytryptamine (5-HTP, 5-HT precursor) and the gene expression of tryptophan hydroxylase 1 (Tph1), which is the key synthetase in the 5-HT biosynthesis in RIN14B cells. Ingestion of 0.2 ml WHH1889 (1´10⁹ cfu/ml) in a chronic unpredictable mild stress (CUMS) mouse model of depression for five weeks normalised depressive and anxiety-like behaviours in the forced swim test, tail suspension test, sucrose preference test, and open field test. Meanwhile, the CUMS-induced elevated level of serum corticosterone and declined levels of hippocampal 5-HT and 5-HTP were reversed by WHH1889. Furthermore, the disturbances of the gut microbiome composition with reduced microbial diversity were also improved by WHH1889, accompanied by the increased colonic 5-HTP level and Tph1 gene expression. In summary, these findings indicate that WHH1889 exerts antidepressant-like effects on CUMS mice, which is associated with the modulations of the 5-HT/5-HTP metabolism and gut microbiome composition. Therefore, ingestion of the L. helveticus strain WHH1889 with antidepressant potentials may become an encouraging therapeutic option in the treatment of depression.

Gut Microbial Dysbiosis and Cognitive Impairment in Bipolar Disorder: Current Evidence

Recent studies have reported that the gut microbiota influences mood and cognitive function through the gut-brain axis, which is involved in the pathophysiology of neurocognitive and mental disorders, including Parkinson’s disease, Alzheimer’s disease, and schizophrenia. These disorders have similar pathophysiology to that of cognitive dysfunction in bipolar disorder (BD), including neuroinflammation and dysregulation of various neurotransmitters (i.e., serotonin and dopamine). There is also emerging evidence of alterations in the gut microbial composition of patients with BD, suggesting that gut microbial dysbiosis contributes to disease progression and cognitive impairment in BD. Therefore, microbiota-centered treatment might be an effective adjuvant therapy for BD-related cognitive impairment. Given that studies focusing on connections between the gut microbiota and BD-related cognitive impairment are lagging behind those on other neurocognitive disorders, this review sought to explore the potential mechanisms of how gut microbial dysbiosis affects cognitive function in BD and identify potential microbiota-centered treatment.

How to Improve Health with Biological Agents-Narrative Review

The proper functioning of the human organism is dependent on a number of factors. The health condition of the organism can be often enhanced through appropriate supplementation, as well as the application of certain biological agents. Probiotics, i.e., live microorganisms that exert a beneficial effect on the health of the host when administered in adequate amounts, are often used in commonly available dietary supplements or functional foods, such as yoghurts. Specific strains of microorganisms, administered in appropriate amounts, may find application in the treatment of conditions such as various types of diarrhoea (viral, antibiotic-related, caused by Clostridioides difficile), irritable bowel syndrome, ulcerative colitis, Crohn’s disease, or allergic disorders. In contrast, live microorganisms capable of exerting influence on the nervous system and mental health through interactions with the gut microbiome are referred to as psychobiotics. Live microbes are often used in combination with prebiotics to form synbiotics, which stimulate growth and/or activate the metabolism of the healthy gut microbiome. Prebiotics may serve as a substrate for the growth of probiotic strains or fermentation processes. Compared to prebiotic substances, probiotic microorganisms are more tolerant of environmental conditions, such as oxygenation, pH, or temperature in a given organism. It is also worth emphasizing that the health of the host may be influenced not only by live microorganisms, but also by their metabolites or cell components, which are referred to as postbiotics and paraprobiotics. This work presents the mechanisms of action employed by probiotics, prebiotics, synbiotics, postbiotics, paraprobiotics, and psychobiotics, together with the results of studies confirming their effectiveness and impact on consumer health.

Probiotic Properties, Prebiotic Fermentability, and GABA-Producing Capacity of Microorganisms Isolated from Mexican Milk Kefir Grains: A Clustering Evaluation for Functional Dairy Food Applications

Isolation and functional characterization of microorganisms are relevant steps for generating starter cultures with functional properties, and more recently, those related to improving mental health. Milk kefir grains have been recently investigated as a source of health-related strains. This study focused on the evaluation of microorganisms from artisanal Mexican milk kefir grains regarding probiotic properties, in vitro fermentability with commercial prebiotics (lactulose, inulin, and citrus pectin), and γ-aminobutyric acid (GABA)-producing capacity. Microorganisms were identified belonging to genera Lactococcus, Lactobacillus, Leuconostoc, and Kluyveromyces. The probiotic properties were assessed by aggregation abilities, antimicrobial activity, antibiotic susceptibility, and resistance to in vitro gastrointestinal digestion, showing a good performance compared with commercial probiotics. Most of isolates maintained a concentration above 6 log colony forming units/mL after the intestinal phase. Specific isolates of Kluyveromyces (BIOTEC009 and BIOTEC010), Leuconostoc (BIOTEC011 and BIOTEC012), and Lactobacillus (BIOTEC014 and BIOTEC15) showed a high fermentability in media supplemented with commercial prebiotics. The capacity to produce GABA was classified as medium for L. lactis BIOTEC006, BIOTEC007, and BIOTEC008; K. lactis BIOTEC009; L. pseudomesenteroides BIOTEC012; and L. kefiri BIOTEC014, and comparable to that obtained for commercial probiotics. Finally, a multivariate approach was performed, allowing the grouping of 2-5 clusters of microorganisms that could be further considered new promising cultures for functional dairy food applications.

Probiotics-targeting new milestones from gut health to mental health

Conventional probiotic food research was primarily focused on their benefits for gut health. Recently with the confirmation that the gut microbiota has a bidirectional connection with the brain, it is being proposed that modification of the microbiota can possibly extirpate neurological diseases. Development of probiotic foods and formulations for neural health benefits has garnered interest, with a renewed focus. In this context, this review discusses the evidences collected on the anxiolytic and antidepressant effects of probiotics, especially during the time span of 2015-till now. Although, more clinical trials are necessary to elucidate the exact mechanism of probiotic mode of action but several of the established probiotic strains have been investigated and it appears that few of them have demonstrated their potential as 'psychobiotics'. The formulation of new psychobiotic-based therapeutics is in the spotlight. It is expected that in near future, biological effect of probiotics on neurological conditions will open up an entirely new avenue for personalized medication and healthcare in mental health, and they can be tailored according to the gut-microbiota of specific individuals.

Gutted! Unraveling the Role of the Microbiome in Major Depressive Disorder

Microorganisms can be found in virtually any environment. In humans, the largest collection of microorganisms is found in the gut ecosystem. The adult gut microbiome consists of more genes than its human host and typically spans more than 60 genera from across the taxonomic tree. In addition, the gut contains the largest number of neurons in the body, after the brain. In recent years, it has become clear that the gut microbiome is in communication with the brain, through the gut-brain axis. A growing body of literature shows that the gut microbiome plays a shaping role in a variety of psychiatric disorders, including major depressive disorder (MDD). In this review, the interplay between the microbiome and MDD is discussed in three facets. First, we discuss factors that affect the onset/development of MDD that also greatly impinge on the composition of the gut microbiota-especially diet and stressful life events. We then examine the interplay between the microbiota and MDD. We examine evidence suggesting that the microbiota is altered in MDD, and we discuss why the microbiota should be considered during MDD treatment. Finally, we look toward the future and examine how the microbiota might become a therapeutic target for MDD. This review is intended to introduce those familiar with the neurological and psychiatric aspects of MDD to the microbiome and its potential role in the disorder. Although research is in its very early days, with much yet to be the understood, the microbiome is offering new avenues for developing potentially novel strategies for managing MDD.

Psychobiotic Supplementation of PS128TM Improves Stress, Anxiety, and Insomnia in Highly Stressed Information Technology Specialists: A Pilot Study

Background: Information technology (IT) is an industry related to the production of computers, information processing, and telecommunications. Such industries heavily rely on the knowledge and solutions provided by IT specialists. Previous reports found that the subjective stress scores were higher in IT specialists who developed diabetes, hypertension, and depression. Specific probiotics, known as psychobiotics, may alleviate stress and mood symptoms. This study aimed to examine whether an 8-week intervention of a novel psychobiotic, Lactobacillus plantarum PS128^TM (PS128^TM), improved self-perceived stress and mood symptoms among high-stress IT specialists.

Methods: This open-label, single-arm, baseline-controlled study included IT specialists from a large IT company in Northern Taiwan. Participants with a Perceived Stress Scale (PSS) 10-item version score of 27 or higher were included. Participants were asked to take two capsules containing PS128^TM powder, equivalent to 20 billion colony-forming units, daily. Self-report measures, such as the Job Stress Scale, Visual Analog Scale of Stress, the Insomnia Severity Index, the State and Trait Anxiety Index, the Questionnaire for Emotional Trait and State, the Patient Health Questionnaire, the Quality of Life Enjoyment and Satisfaction Questionnaire, and Gastrointestinal Severity Index were compared at baseline and at the end of the trial period. The primary outcome was a 20% reduction in the PSS score at endpoint. Objective measures included salivary levels of stress biomarkers, including cortisol, α-amylase, immunoglobulin A, lactoferrin, and lysozymes, as well as results of the Test of Attentional Performance.

Results: Of the 90 eligible IT specialists, 36 met the inclusion criteria. After the 8-week trial period, significant improvements in self-perceived stress, overall job stress, job burden, cortisol level, general or psychological health, anxiety, depression, sleep disturbances, quality of life, and both positive and negative emotions were found.

Conclusion: Our results suggest that PS128^TM has the distinct advantage of providing stress relief and can improve mental health for people with a high-stress job. Future placebo-controlled studies are warranted to explore the effect and underlying mechanisms of action of PS128^TM.

Clinical Trial Registration:https://clinicaltrials.gov/ (identifier: NCT04452253-sub-project 2).

Psychobiotics: Mechanisms of Action, Evaluation Methods and Effectiveness in Applications with Food Products

The gut-brain-microbiota axis consists of a bilateral communication system that enables gut microbes to interact with the brain, and the latter with the gut. Gut bacteria influence behavior, and both depression and anxiety symptoms are directly associated with alterations in the microbiota. Psychobiotics are defined as probiotics that confer mental health benefits to the host when ingested in a particular quantity through interaction with commensal gut bacteria. The action mechanisms by which bacteria exert their psychobiotic potential has not been completely elucidated. However, it has been found that these bacteria provide their benefits mostly through the hypothalamic-pituitary-adrenal (HPA) axis, the immune response and inflammation, and through the production of neurohormones and neurotransmitters. This review aims to explore the different approaches to evaluate the psychobiotic potential of several bacterial strains and fermented products. The reviewed literature suggests that the consumption of psychobiotics could be considered as a viable option to both look after and restore mental health, without undesired secondary effects, and presenting a lower risk of allergies and less dependence compared to psychotropic drugs.

Microbiota-Gut-Brain Axis: New Therapeutic Opportunities

The traditional fields of pharmacology and toxicology are beginning to consider the substantial impact our gut microbiota has on host physiology. The microbiota-gut-brain axis is emerging as a particular area of interest and a potential new therapeutic target for effective treatment of central nervous system disorders, in addition to being a potential cause of drug side effects. Microbiota-gut-brain axis signaling can occur via several pathways, including via the immune system, recruitment of host neurochemical signaling, direct enteric nervous system routes and the vagus nerve, and the production of bacterial metabolites. Altered gut microbial profiles have been described in several psychiatric and neurological disorders. Psychobiotics, live biotherapeutics or substances whose beneficial effects on the brain are bacterially mediated, are currently being investigated as direct and/or adjunctive therapies for psychiatric and neurodevelopmental disorders and possibly for neurodegenerative disease, and they may emerge as new therapeutic options in the clinical management of brain disorders.

Effects of Lactobacillus plantarum PS128 on Children with Autism Spectrum Disorder in Taiwan: A Randomized, Double-Blind, Placebo-Controlled Trial

This four-week, randomized, double-blind, placebo-controlled study investigated the effects of Lactobacillus plantarum PS128 (PS128) on boys with autism spectrum disorder (ASD) aged 7-15 in Taiwan. All subjects fulfilled the criteria for ASD diagnosis of DSM-V and the Autism Diagnostic Interview-Revised (ADI-R). Questionnaires used for the primary outcome measure include the Autism Behavior Checklist-Taiwan version (ABC-T), the Social Responsiveness Scale (SRS) and the Child Behavior Checklist (CBCL). The Swanson, Nolan, and Pelham-IV-Taiwan version (SNAP-IV) and the Clinical Global Impression-improvement (CGI-I) were used for the secondary outcome measure. The results showed that PS128 ameliorated opposition/defiance behaviors, and that the total score of SNAP-IV for younger children (aged 712) improved significantly compared with the placebo group. Additionally, several elements were also notably improved in the PS128 group after 28-day consumption of PS128. Further studies are needed to better clarify the effects of PS128 for younger children with ASD on broader symptoms.

Effect of probiotic interventions on depressive symptoms: A narrative review evaluating systematic reviews

Depression is one of the most prevalent mental illnesses and is often associated with various other medical disorders. Since the 1980s, the primary pharmacological treatment has been antidepressants, but due to the recent discovery of the association between the gut microbiome and mental health, probiotics have been proposed as an adjunctive or alternate treatment. In this narrative review, we aim to provide a holistic perspective by synthesizing and evaluating existing evidence, discussing key biological mechanisms, exploring the history of probiotic use, and appreciating the influence of modern diet on mental health. Five online databases were searched for relevant studies up to December 2017. Systematic reviews that included randomized controlled trials assessing the efficacy of probiotics in the treatment of depressive symptoms were included. Seven systematic reviews met the inclusion criteria. Three of these reviews conducted meta-analyses, out of which, two concluded that probiotics improved depressive symptoms in the sample population. Out of the four reviews that conducted qualitative analysis, three reviews concluded that probiotics have the potential to be used as a treatment. Due to the differences in clinical trials, a definitive effect of probiotics on depressive symptoms cannot be concluded. Nonetheless, probiotics seem to potentially produce a significant therapeutic effect for subjects with pre-existing depressive symptoms. Further studies are warranted for definitive conclusions.