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

Towards a personalized prediction, prevention and therapy of insomnia: gut microbiota profile can discriminate between paradoxical and objective insomnia in post-menopausal women

Background

Insomnia persists as a prevalent sleep disorder among middle-aged and older adults, significantly impacting quality of life and increasing susceptibility to age-related diseases. It is classified into objective insomnia (O-IN) and paradoxical insomnia (P-IN), where subjective and objective sleep assessments diverge. Current treatment regimens for both patient groups yield unsatisfactory outcomes. Consequently, investigating the neurophysiological distinctions between P-IN and O-IN is imperative for devising novel precision interventions aligned with primary prediction, targeted prevention, and personalized medicine (PPPM) principles.Working hypothesis and methodology.Given the emerging influence of gut microbiota (GM) on sleep physiology via the gut-brain axis, our study focused on characterizing the GM profiles of a well-characterized cohort of 96 Italian postmenopausal women, comprising 54 insomniac patients (18 O-IN and 36 P-IN) and 42 controls, through 16S rRNA amplicon sequencing. Associations were explored with general and clinical history, sleep patterns, stress, hematobiochemical parameters, and nutritional patterns.

Results

Distinctive GM profiles were unveiled between O-IN and P-IN patients. O-IN patients exhibited prominence in the Coriobacteriaceae family, including Collinsella and Adlercreutzia, along with Erysipelotrichaceae, Clostridium, and Pediococcus. Conversely, P-IN patients were mainly discriminated by Bacteroides, Staphylococcus, Carnobacterium, Pseudomonas, and respective families, along with Odoribacter.

Conclusions

These findings provide valuable insights into the microbiota-mediated mechanism of O-IN versus P-IN onset. GM profiling may thus serve as a tailored stratification criterion, enabling the identification of women at risk for specific insomnia subtypes and facilitating the development of integrated microbiota-based predictive diagnostics, targeted prevention, and personalized therapies, ultimately enhancing clinical effectiveness.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-024-00369-1.

The effects of Lactobacillus plantarum PS128 in patients with major depressive disorder: an eight-week double-blind, placebo-controlled study

Major depressive disorder (MDD) is a complex mental disorder, potentially linked to the gut-microbiota-brain axis. Probiotics like Lactobacillus plantarum PS128 (PS128) may improve depressive symptoms by modulating the gut microbiota based on our previous open trial. We conducted an 8-week double-blind, placebo-controlled trial to investigate the impact of PS128 on depression severity, markers of inflammation and gut permeability, and the gut microbiota composition in 32 patients with MDD with stable antidepressant treatment but moderate symptom severity. Following the 8-week intervention, both the Hamilton Depression Rating Scale-17 score (HAMD), and Depression and Somatic Symptoms Scale (DSSS) showed a significant decrease in both groups (p<0.001). However, there was no significant difference in the change of depression severity between groups (p=0.203). Moreover, alterations in serum levels of high sensitivity C-reactive protein, interleukin-6, tumor necrosis factor-α, and intestinal fatty acid binding protein, as well as changes in the gut microbiota composition, did not exhibit significant differences before and after intervention or between the groups. In comparison to the placebo group, our study did not find significant effects of PS128 on depressive symptoms, biomarkers of inflammation and gut permeability, and the overall gut microbiota composition. Nonetheless, we observed a potential impact of PS128 on the symbiosis of specific taxa. To comprehensively understand the psychophysiological effects of PS128 in patients with MDD, further research with a larger sample size is imperative.

Lacticaseibacillus paracasei PS23 increases ghrelin levels and modulates microbiota composition: a post-hoc analysis of a randomized controlled study

Muscle damage can occur due to excessive, high-intensity, or inappropriate exercise. It is crucial for athletes and sports enthusiasts to have access to ways that expedite their recovery and alleviate discomfort. Our previous clinical trial demonstrated the anti-inflammatory and muscle damage-ameliorating properties of Lacticaseibacillus paracasei PS23 (PS23), prompting us to further explore the role of this probiotic in muscle damage recovery. This post-hoc analysis of a randomized controlled study investigated potential mediators between the intake of PS23 and the prevention of strength loss after muscle damage. We recruited 105 students from a sports university who had participated in the previously published clinical trial. These participants were randomly allocated to three groups, receiving capsuled live PS23 (L-PS23), heat-treated PS23 (HT-PS23), or a placebo over a period of six weeks. Baseline and endpoint measurements were taken for the levels of circulating ghrelin and other blood markers, stress, mood, quality of life, and the fecal microbiota. A significant increase in ghrelin levels was recorded in the L-PS23 group compared to the other groups. Additionally, both L-PS23 and HT-PS23 interventions led to positive shifts in the gut microbiota composition, particularly in elevated Lacticaseibacillus, Blautia, and Lactobacillus populations. The abundance of these bacteria was positively correlated with exercise performance and inversely correlated with inflammatory markers. In conclusion, dietary supplementation with PS23 may enhance exercise performance and influence muscle damage by increasing ghrelin levels and modulating the gut microbiota composition. Further clarification of the possible mechanisms and clinical implications is required.

Bifidobacterium longum 1714 improves sleep quality and aspects of well-being in healthy adults: a randomized, double-blind, placebo-controlled clinical trial

Stress and sleep are linked with overall well-being. Bifidobacterium longum 1714 has been shown to influence stress responses and modulate neural responses during social stress, and influence sleep quality during examination stress in healthy adults. Here, we explored the ability of this strain to alter sleep quality in adults using subjective and objective measures. Eighty-nine adults (18-45y) with impaired sleep quality assessed with the Pittsburgh Sleep Quality Index (PSQI) and with a global score ≥ 5 were randomized to receive B. longum 1714 or placebo daily for eight weeks. Assessing the effect of the strain on PSQI global score was the primary objective. Secondary objectives assessed sleep quality and well-being subjectively and sleep parameters using actigraphy objectively. While PSQI global score improved in both groups, B. longum 1714 significantly improved the PSQI component of sleep quality (p < 0.05) and daytime dysfunction due to sleepiness (p < 0.05) after 4 weeks and social functioning (p < 0.05) and energy/vitality (p < 0.05) after 8 weeks, compared to placebo. No significant effect on actigraphy measures were observed. The 1714 strain had a mild effect on sleep, demonstrated by a faster improvement in sleep quality at week 4 compared to placebo, although overall improvements after 8 weeks were similar in both groups. B. longum 1714 improved social functioning and increased energy/vitality in line with previous work that showed the strain modulated neural activity which correlated with enhanced vitality/reduced mental fatigue (ClinicalTrials.gov: NCT04167475).

Gut microbiota: Candidates for a novel strategy for ameliorating sleep disorders

The aim of this review was to evaluate the feasibility of treating sleep disorders using novel gut microbiota intervention strategies. Multiple factors can cause sleep disorders, including an imbalance in the gut microbiota. Studies of the microbiome-gut-brain axis have revealed bidirectional communication between the central nervous system and gut microbes, providing a more comprehensive understanding of mood and behavioral regulatory patterns. Changes in the gut microbiota and its metabolites can stimulate the endocrine, nervous, and immune systems, which regulate the release of neurotransmitters and alter the activity of the central nervous system, ultimately leading to sleep disorders. Here, we review the main factors affecting sleep, discuss possible pathways and molecular mechanisms of the interaction between sleep and the gut microbiota, and compare common gut microbiota intervention strategies aimed at improving sleep physiology.

The Survival of Psychobiotics in Fermented Food and the Gastrointestinal Tract: A Review

In recent years, scientists have been particularly interested in the gut-brain axis, as well as the impact of probiotics on the nervous system. This has led to the creation of the concept of psychobiotics. The present review describes the mechanisms of action of psychobiotics, their use in food products, and their viability and survival during gastrointestinal passage. Fermented foods have a high potential of delivering probiotic strains, including psychobiotic ones. However, it is important that the micro-organisms remain viable in concentrations ranging from about 10⁶ to 10⁹ CFU/mL during processing, storage, and digestion. Reports indicate that a wide variety of dairy and plant-based products can be effective carriers for psychobiotics. Nonetheless, bacterial viability is closely related to the type of food matrix and the micro-organism strain. Studies conducted in laboratory conditions have shown promising results in terms of the therapeutic properties and viability of probiotics. Because human research in this field is still limited, it is necessary to broaden our understanding of the survival of probiotic strains in the human digestive tract, their resistance to gastric and pancreatic enzymes, and their ability to colonize the microbiota.

Psychobiotic Lactobacillus plantarum JYLP-326 relieves anxiety, depression, and insomnia symptoms in test anxious college via modulating the gut microbiota and its metabolism

Introduction

Test anxiety is a common issue among college students, which can affect their physical and psychological health. However, effective interventions or therapeutic strategies are still lacking. This study aims to evaluate the potential effects of Lactobacillus plantarum JYLP-326 on test anxious college students.

Methods

Sixty anxious students were enrolled and randomly allocated to the placebo group and the probiotic group. Both groups were instructed to take placebo and JYLP-326 products twice per day for three weeks, respectively. Thirty unanxious students with no treatments were assigned to a regular control group. The anxiety, depression, and insomnia questionnaires were used to measure students' mental states at the baseline and the end of this study. 16S rRNA sequencing and untargeted metabolomics were performed to analyze the changes in the gut microbiota and fecal metabolism.

Results

The questionnaire results suggested that JYLP-326 administration could relieve the symptoms of anxiety, depression, and insomnia in test anxious students. The gut microbiomes of the placebo group showed a significantly greater diversity index than the control group (p < 0.05). An increased abundance of Bacteroides and Roseburia at the genus level was observed in the placebo group, and the relative abundance of Prevotella and Bifidobacterium decreased. Whereas, JYLP-326 administration could partly restore the disturbed gut microbiota. Additionally, test anxiety was correlated with disordered fecal metabolomics such as a higher Ethyl sulfate and a lower Cyclohexylamine, which could be reversed after taking JYLP-326. Furthermore, the changed microbiota and fecal metabolites were significantly associated with anxiety-related symptoms.

Conclusion

The results indicate that the intervention of L. plantarum JYLP-326 could be an effective strategy to alleviate anxiety, depression, and insomnia in test anxious college students. The potential mechanism underlying this effect could be related to the regulation of gut microbiota and fecal metabolites.

Nutrient combinations exhibit universal antianxiety, antioxidant, neuro-protecting, and memory-improving activities

Anxiety disorders are the most common mental disorders and, without proper treatment, may lead to severe conditions: e.g., somatic disorders or permanent damage to central nervous system. Although there are drugs in clinical trials, this study focuses on exploring the efficacy of nutrients in treating these diseases. We built different zebrafish models and screened several nutrient combinations for their antianxiety, antioxidant, neuro-protecting, and memory-improving activities. Our results showed that the combinations of nutrients (e.g., Walnut Peptides + Theanine at 14.2 + 33.3 μg/ml) have similar or better activities than the positive control drugs. In addition, we discovered that the effects of the nutrients in the above four aspects were universal and highly related. This study is noteworthy as it suggested that nutrients could be healthier and greener drug alternatives and provide similar or better universal treatments for anxiety and related conditions.

Lactic Acid Bacteria: A Promising Tool for Menopausal Health Management in Women

Menopause is a period during which women undergo dramatic hormonal changes. These changes lead to physical and mental discomfort, are greatly afflictive, and critically affect women's lives. However, the current safe and effective management measures for women undergoing menopause are insufficient. Several probiotic functions of lactic acid bacteria (LAB) have been recognized, including alleviation of lactose intolerance, protection of digestive tract health, activation of the immune system, protection against infections, improvement of nutrient uptake, and improvement of the microbiota. In this review, we highlight the currently available knowledge of the potential protective effects of LAB on preventing or mitigating menopausal symptoms, particularly in terms of maintaining balance in the vaginal microbiota, reducing bone loss, and regulating the nervous system and lipid metabolism. Given the increasing number of women entering menopause and the emphasis on the management of menopausal symptoms, LAB are likely to soon become an indispensable part of clinical/daily care for menopausal women. Herein, we do not intend to provide a comprehensive analysis of each menopausal disorder or to specifically judge the reliability and safety of complementary therapies; rather, we aim to highlight the potential roles of LAB in individualized treatment strategies for the clinical management of menopause.

Recent developments in the probiotics as live biotherapeutic products (LBPs) as modulators of gut brain axis related neurological conditions

Probiotics have been defined as “living microorganisms that create health benefits in the host when taken in sufficient amounts. Recent developments in the understanding of the relationship between the microbiom and its host have shown evidence about the promising potential of probiotics to improve certain health problems. However, today, there are some confusions about traditional and new generation foods containing probiotics, naming and classifications of them in scientific studies and also their marketing. To clarify this confusion, the Food and Drug Administration (FDA) declared that it has made a new category definition called "live biotherapeutic products" (LBPs). Accordingly, the FDA has designated LBPs as “a biological product that: i)contains live organisms, such as bacteria; ii)is applicable to the prevention, treatment, or cure of a disease/condition of human beings; and iii) is not a vaccine”. The accumulated literature focused on LBPs to determine effective strains in health and disease, and often focused on obesity, diabetes, and certain diseases like inflammatory bowel disease (IBD).However, microbiome also play an important role in the pathogenesis of diseases that age day by day in the modern world via gut-brain axis. Herein, we discuss the novel roles of LBPs in some gut-brain axis related conditions in the light of recent studies. This article may be of interest to a broad readership including those interested in probiotics as LBPs, their health effects and safety, also gut-brain axis.

Does the Gut Microbial Metabolome Really Matter? The Connection between GUT Metabolome and Neurological Disorders

Herein we gathered updated knowledge regarding the alterations of gut microbiota (dysbiosis) and its correlation with human neurodegenerative and brain-related diseases, e.g., Alzheimer’s and Parkinson’s. This review underlines the importance of gut-derived metabolites and gut metabolic status as the main players in gut-brain crosstalk and their implications on the severity of neural conditions. Scientific evidence indicates that the administration of probiotic bacteria exerts beneficial and protective effects as reduced systemic inflammation, neuroinflammation, and inhibited neurodegeneration. The experimental results performed on animals, but also human clinical trials, show the importance of designing a novel microbiota-based probiotic dietary supplementation with the aim to prevent or ease the symptoms of Alzheimer’s and Parkinson’s diseases or other forms of dementia or neurodegeneration.

Psychobiotic supplementation of HK-PS23 improves anxiety in highly stressed clinical nurses: a double-blind randomized placebo-controlled study

Nurses often experience adverse health effects associated with increasing levels of work-related stress. Stress may induce systemic effects through the HPA axis, glucocorticoid responses, and inflammatory cascades. Psychobiotics may help alleviate stress through associations of the microbiota, anti-inflammation factors, and the gut-brain axis. We aimed to investigate whether interventions with a psychobiotic, heat-killed (HK)-PS23 cells, may help improve perceived stress, anxiety, and related biological markers among highly stressed clinical nurses. This double-blind, randomized, placebo-controlled study included seventy clinical nurses from a medical center in Northern Taiwan who scored 27 or higher on the 10-item version of the Perceived Stress Scale (PSS), and participants were randomized into either taking HK-PS23 or a placebo for 8 weeks. Baseline and endpoint results of the PSS, Job Stress Scale, State and Trait Anxiety Index (STAI), emotional questionnaires, gastrointestinal severity questionnaires, Trails Marking Tests, blood biological markers, and sleep data were analyzed. While both groups demonstrated improvements in most measures over time, only the blood cortisol measure demonstrated significant group differences after the 8-week trial. Further analyses of the subgroup with higher anxiety (nurses with STAI ≥ 103) revealed that anxiety states had improved significantly in the HK-PS23 group but not in the placebo group. In summary, this placebo-controlled trial found significant reduction in the level of blood cortisol after 8 weeks of HK-PS23 use. The distinctive anxiolytic effects of HK-PS23 may be beneficial in improving perceived anxiety and stress hormone levels in female nurses under pressure. Clinical trial registration: https://clinicaltrials.gov/, identifier: NCT04452253-sub-project 1.

ROLE OF GUT MICROBIOTA IN DEPRESSION: UNDERSTANDING MOLECULAR PATHWAYS, RECENT RESEARCH, AND FUTURE DIRECTION

Gut microbiota, also known as the "second brain" in humans because of the regulatory role it has on the central nervous system via neuronal, chemical and immune pathways. It has been proven that there exists a bidirectional communication between the gut and the brain. Increasing evidence supports that this crosstalk is linked to the etiology and treatment of depression. Reports suggest that the gut microbiota control the host epigenetic machinery in depression and gut dysbiosis causes negative epigenetic modifications via mechanisms like histone acetylation, DNA methylation and non-coding RNA mediated gene inhibition. The gut microbiome can be a promising approach for the management of depression. The diet and dietary metabolites like kynurenine, tryptophan, and propionic acid also greatly influence the microbiome composition and thereby, the physiological activities. This review gives a bird-eye view on the pathological updates and currently used treatment approaches targeting the gut microbiota in depression.

Impact of Environmental Pollutants on Gut Microbiome and Mental Health via the Gut–Brain Axis

Over the last few years, the microbiome has emerged as a high-priority research area to discover missing links between brain health and gut dysbiosis. Emerging evidence suggests that the commensal gut microbiome is an important regulator of the gut–brain axis and plays a critical role in brain physiology. Engaging microbiome-generated metabolites such as short-chain fatty acids, the immune system, the enteric nervous system, the endocrine system (including the HPA axis), tryptophan metabolism or the vagus nerve plays a crucial role in communication between the gut microbes and the brain. Humans are exposed to a wide range of pollutants in everyday life that impact our intestinal microbiota and manipulate the bidirectional communication between the gut and the brain, resulting in predisposition to psychiatric or neurological disorders. However, the interaction between xenobiotics, microbiota and neurotoxicity has yet to be completely investigated. Although research into the precise processes of the microbiota–gut–brain axis is growing rapidly, comprehending the implications of environmental contaminants remains challenging. In these milieus, we herein discuss how various environmental pollutants such as phthalates, heavy metals, Bisphenol A and particulate matter may alter the intricate microbiota–gut–brain axis thereby impacting our neurological and overall mental health.

Probiotics, prebiotics and postbiotics for better sleep quality: a narrative review

There is a growing prevalence of sleep problems and insomnia worldwide, urging the development of new treatments to tackle this increase. Several studies have suggested that the gut microbiome might influence sleep quality. The gut microbiome affects the host's health via the production of metabolites and compounds with neuroactive and immunomodulatory properties, which include short-chain fatty acids, secondary bile acids and neurotransmitters. Several of these metabolites and compounds are independently known as wakefulness-promoting (serotonin, epinephrine, dopamine, orexin, histamine, acetylcholine, cortisol) or sleep-promoting (gamma-aminobutyric acid, melatonin). The primary aim of this review was to evaluate the potential of pro-, pre- and postbiotic treatments to improve sleep quality. Additionally, we aimed to evaluate whether each of the treatments could ameliorate stress and anxiety, which are known to bidirectionally correlate with sleep problems. Lastly, we provided a mechanistic explanation for our findings. A literature search was conducted using PubMed, Scopus, Web of Science, and Google Scholar to compare all human trials that met our inclusion criteria and were published before November 2021. We furthermore discussed relevant findings from animal experiments to provide a mechanistic insight. While several studies found that sleep latency, sleep length, and cortisol levels improved after pro-, pre- or postbiotic treatment, others did not show any significant improvements for sleep quality, stress, or anxiety. These discrepancies can be explained by between-study variations in study designs, study populations, treatments, type and level of distress, and sex differences. We conclude that the trials discussed provide some evidence for prebiotics, postbiotics, and traditional probiotics, such as those belonging to lactobacilli and bifidobacteria, to improve sleep quality and stress, but stronger evidence might be found in the future after implementing the methodological adjustments that are suggested in this review.

Psychobiotic Therapy: Method to Reinforce the Immune System

Psychobiotics are probiotic microorganisms that beneficially affect the central nervous system functions mediated by the gut-brain axis, improving the host’s immune system. Psychobiotic microorganisms can regulate brain pathways and serotonin production (mood controller). The main microbial genera with psychobiotic characteristics are Lactobacillus, Lactococcus and Bifidobacterium. The daily consumption of psychobiotics is called “Psychobiotic Therapy”. Psychobio-tic therapy has proven antidepressant/anxiolytic properties. Psychobiotic therapy can be used to boost the host’s immune balance against pathogens, for example: virus, bacteria and fungus. Thus, psychobiotic therapy can be a promising strategy to improve and/or maintain the quality of life of people who are healthy or who suffer from anxiety/stress disorders, intestinal dysbiosis and even immunosuppressed people. This is such a hot theme it can surely only be a matter of time for psychobiotic therapy offers an “alternative treatment”, but scientific, for people diagnosed with a variety of mental/immunological disorders. Instead of targeting the mind (brain), we could go for the gut. “This new way of looking at mental health linked to gut health is literally looking at health upside down”.

One Giant Leap from Mouse to Man: The Microbiota-Gut-Brain Axis in Mood Disorders and Translational Challenges Moving towards Human Clinical Trials

The microbiota–gut–brain axis is a bidirectional communication pathway that enables the gut microbiota to communicate with the brain through direct and indirect signaling pathways to influence brain physiology, function, and even behavior. Research has shown that probiotics can improve several aspects of health by changing the environment within the gut, and several lines of evidence now indicate a beneficial effect of probiotics on mental and brain health. Such evidence has prompted the arrival of a new term to the world of biotics research: psychobiotics, defined as any exogenous influence whose effect on mental health is bacterially mediated. Several taxonomic changes in the gut microbiota have been reported in neurodevelopmental disorders, mood disorders such as anxiety and depression, and neurodegenerative disorders such as Alzheimer’s disease. While clinical evidence supporting the role of the gut microbiota in mental and brain health, and indeed demonstrating the beneficial effects of probiotics is rapidly accumulating, most of the evidence to date has emerged from preclinical studies employing different animal models. The purpose of this review is to focus on the role of probiotics and the microbiota–gut–brain axis in relation to mood disorders and to review the current translational challenges from preclinical to clinical research.

Sleep Duration and Hypertension: Epidemiological Evidence and Underlying Mechanisms

While the contribution of several physiological systems to arterial blood pressure regulation has been studied extensively, the role of normal and disrupted sleep as a modifiable determinant of blood pressure control, and in the pathophysiology of hypertension, has only recently emerged. Several sleep disorders, including sleep apnea and insomnia, are thought to contribute to the development of hypertension, although less attention is paid to the relationship between sleep duration and blood pressure independent of sleep disorders per se. Accordingly, this review focuses principally on the physiology of sleep and the consequences of abnormal sleep duration both experimentally and at the population level. Clinical implications for patients with insomnia who may or may not have abbreviated sleep duration are explored. As a corollary, we further review studies of the effects of sleep extension on blood pressure regulation. We also discuss epidemiological evidence suggesting that long sleep may also be associated with hypertension and describe the parabolic relationship between total sleep time and blood pressure. We conclude by highlighting gaps in the literature regarding the potential role of gut microbial health in the cross-communication of lifestyle patterns (exercise, diet, and sleep) with blood pressure regulation. Additionally, we discuss populations at increased risk of short sleep, and specifically the need to understand mechanisms and therapeutic opportunities in women, pregnancy, the elderly, and in African Americans.

The gut microbiome as a target for adjuvant therapy in insomnia disorder

Insomnia is a type of sleep disorder which has negative impacts on the quality of life, mood, cognitive function and health of humans. The etiology of insomnia may be related to many factors such as genetics, biochemistry, neuroendocrine, immune, and psychosocial factors. However, the detailed pathological aspects of insomnia remain unclear. Recent investigation of the microbiome-gut-brain axis enhances our understanding of the role of the gut microbiota in brain-related diseases. Gut microbiome has been shown to be associated with insomnia. However, the available data in this field remain limited and the relevant scientific work has only recently begun. This review aims to summarize the recent literature as an aid to better understanding how the alteration of gut microbiota composition contributes to insomnia while evaluating and prospecting the therapeutic effect of modulating gut microbiota in the treatment of insomnia based on previous publications.

Microbiota-targeted interventions for mental health

PURPOSE OF REVIEW

The gut microbiota has emerged as a key conduit in mental health and is a promising target for interventions. This review provides an update on recent advances in using microbiota-targeted approaches for the management of mental health.

RECENT FINDINGS

Approaches that have emerged as microbiota-targeted interventions in the management of mental health include probiotics, prebiotics, synbiotics, fecal microbiota transplant as well as diet. Among these approaches, probiotic supplementation has been investigated most prominently, providing promising evidence for its use in improving mood and anxiety. There is also growing interest in the use of multistrain probiotics, whole dietary interventions or combined approaches, with encouraging results emerging from recent studies.

SUMMARY

Although the current literature preliminarily supports targeting the microbiota to manage mental health and use as adjuvant therapies for certain brain disorders, large gaps remain and especially data including clinical cohorts remains scarce. Research studies including larger cohorts, well-characterized clinical populations and defined duration and dosage of the intervention are required to develop evidence-based guidelines for microbiota-targeted strategies.

Production of Lactobacillus brevis ProGA28 attenuates stress-related sleep disturbance and modulates the autonomic nervous system and the motor response in anxiety/depression behavioral tests in Wistar-Kyoto rats

AIMS

Many studies have reported that the production of Lactobacillus brevis is beneficial for sleep, but the underlying mechanism remains unclear. Other known beneficial effects of Lactobacillus brevis include improvement of anxious or depressive symptoms and better modulation of the autonomic nervous system, both of which impact sleep. In this study, we investigated whether the sleep benefit of Lactobacillus brevis was associated with the modulating effects on the autonomic nervous system and anxious/depressive symptoms.

MAIN METHODS

Wistar-Kyoto rats were fed the production of Lactobacillus brevis (ProGA28) for the last 2 weeks of treatment before being exposed to case exchange (stress-induced insomnia paradigm). Waking, quiet sleep, and paradoxical sleep states were defined based on polysomnographic measurements. Autonomic functioning was assessed by heart rate variability (HRV). A combined behavioral test was used to evaluate anxiety-like or depressive-like behaviors after the following 2 days.

KEY FINDINGS

In exposure to the dirty cage, the control group had significant prolongation of sleep latency, sleep loss during the first 2 h, and decreased parasympathetic activity and increased sympathetic activity during quiet sleep, which were significantly mitigated in the ProGA28 group. In behavioral tests, the ProGA28 group exhibited significantly less anxiety/depression-like motor responses in the elevated plus maze test, the forced swimming test, and the three-chamber social interaction test. Less initial sleep loss in the ProGA28 group was related to higher parasympathetic activity during quiet sleep, and shorter sleep latency in both groups was associated with longer time staying in the open arm in the elevated plus maze test.

SIGNIFICANCE

These findings suggest that L. brevis ProGA28 can attenuate stress-related sleep disturbance, which may be associated with increased parasympathetic activity and decreased anxiety-like behaviors.

Microbial Therapeutics in Neurocognitive and Psychiatric Disorders

Microbial therapeutics, which include gut biotics and fecal transplantation, are interventions designed to improve the gut microbiome. Gut biotics can be considered as the administration of direct microbial populations. The delivery of this can be done through live microbial flora, certain food like fiber, microbial products (metabolites and elements) obtained through the fermentation of food products, or as genetically engineered substances, that may have therapeutic benefit on different health disorders. Dietary intervention and pharmacological supplements with gut biotics aim at correcting disruption of the gut microbiota by repopulating with beneficial microorganism leading to decrease in gut permeability, inflammation, and alteration in metabolic activities, through a variety of mechanisms of action. Our understanding of the pharmacokinetics of microbial therapeutics has improved with in vitro models, sampling techniques in the gut, and tools for the reliable identification of gut biotics. Evidence from human studies points out that prebiotics, probiotics and synbiotics have the potential for treating and preventing mental health disorders, whereas with paraprobiotics, proteobiotics and postbiotics, the research is limited at this point. Some animal studies point out that gut biotics can be used with conventional treatments for a synergistic effect on mental health disorders. If future research shows that there is a possibility of synergistic effect of psychotropic medications with gut biotics, then a gut biotic or nutritional prescription can be given along with psychotropics. Even though the overall safety of gut biotics seems to be good, caution is needed to watch for any known and unknown side effects as well as the need for risk benefit analysis with certain vulnerable populations. Future research is needed before wide spread use of natural and genetically engineered gut biotics. Regulatory framework for gut biotics needs to be optimized. Holistic understanding of gut dysbiosis, along with life style factors, by health care providers is necessary for the better management of these conditions. In conclusion, microbial therapeutics are a new psychotherapeutic approach which offer some hope in certain conditions like dementia and depression. Future of microbial therapeutics will be driven by well-done randomized controlled trials and longitudinal research, as well as by replication studies in human subjects.

Lactobacillus plantarum PS128 Promotes Intestinal Motility, Mucin Production, and Serotonin Signaling in Mice

Lactobacillus plantarum PS128 has been reported as a psychobiotic to improve mental health through the gut–brain axis in experimental animal models. To explore its mechanism of action in the gut, this study aimed to analyze the effects of L. plantarum PS128 ingestion on naïve and loperamide (Lop)-induced constipation mice. We found that, in the two mouse models, the weight, number, and water content of feces in the L. plantarum PS128 group were higher than those in the vehicle control group. Histological observation revealed that L. plantarum PS128 increased the level of colonic mucins including the major mucin MUC2. In addition, the charcoal meal test showed that L. plantarum PS128 significantly increased the small intestine transit in naïve mice, but not in the Lop-treated mice. Since intestinal serotonin has been found to modulate motility, we further analyzed the expression of genes related to serotonin signal transduction in the small intestine of naïve mice. The results showed that L. plantarum PS128 significantly altered the expression levels of Tph1, Chga, Slc6a4, and Htr4, but did not affect the expression levels of Tph2, Htr3a, and Maoa. Furthermore, immunohistochemistry revealed that L. plantarum PS128 significantly increased the number of serotonin-containing intestinal cells in mice. Taken together, our results suggest that L. plantarum PS128 could promote intestinal motility, mucin production, and serotonin signal transduction, leading to a laxative effect in mice.