The "psychomicrobiotic": Targeting microbiota in major psychiatric disorders: A systematic review

Cognition and gut microbiota in schizophrenia spectrum and mood disorders: A systematic review

FRILEUX, M., BOLTRI M. and al. Cognition and Gut microbiota in schizophrenia spectrum and mood disorders: a Systematic Review. NEUROSCI BIOBEHAV REV (1) 2024 Schizophrenia spectrum disorders and major mood disorders are associated with cognitive impairments. Recent studies suggest a link between gut microbiota composition and cognitive functioning. Here, we review the relationship between gut microbiota and cognition in these disorders. To do this, we conducted a systematic review, searching Cochrane Central Register of Controlled Trials, EBSCOhost, Embase, Pubmed, Scopus, and Web of Science. Studies were included if they investigated the relationship between gut microbiota composition and cognitive function through neuropsychological assessments in patients with bipolar, depressive, schizophrenia spectrum, and other psychotic disorders. Ten studies were identified. Findings underscore a link between gut dysbiosis and cognitive impairment. This relationship identified specific taxa (Haemophilus, Bacteroides, and Alistipes) as potential contributors to bolstered cognitive performance. Conversely, Candida albicans, Toxoplasma gondii, Streptococcus and Deinococcus were associated with diminished performance on cognitive assessments. Prebiotics and probiotics interventions were associated with cognitive enhancements, particularly executive functions. These results emphasize the role of gut microbiota in cognition, prompting further exploration of the underlying mechanisms paving the way toward precision psychiatry.

Assessing the causal association between sleep apnea and the human gut microbiome composition: A two-sample Mendelian randomization study

Background

Studies have linked gut microbiota dysbiosis with sleep apnea; however, no causal relationship was found in human subjects. Finding new targets for the pathophysiology of sleep apnea might be made possible by systematically investigating the causal relationship between the human gut microbiota and sleep apnea.

Methods

A two-sample Mendelian randomization analysis was conducted. The human gut microbiome composition data, spanning five taxonomic levels, were acquired from a genome-wide association study that included 18,340 participants from 24 cohorts. Genome-wide association study data for sleep apnea were obtained from the Sleep Disorder Knowledge Portal for primary analysis and the FinnGen consortium for meta-analysis. Sensitivity analyses were conducted to evaluate heterogeneity and pleiotropy.

Results

Using inverse-variance weighted analysis, eight microbial taxa were initially found to be substantially linked with the apnea-hypopnea index. Only three microbial taxa remained significant associations with sleep apnea when combined with the FinnGen consortium (the class Bacilli: B = 8.21%, 95% CI = 0.93%-15.49%; p = 0.03; the order Lactobacillales: B = 7.55%, 95% CI = 0.25%-4.85%; p = 0.04; the genus RuminococcaceaeUCG009: B = -21.63%, 95% CI = -41.47% to -1.80%; p = 0.03).

Conclusions

Sleep apnea may lead to gut dysbiosis as significant reductions in butyrate-producing bacteria and increases in lactate-producing bacteria. By integrating genomes and metabolism, the evidence that three microbiome species are causally linked to sleep apnea may offer a fresh perspective on the underlying mechanisms of the condition.

Effectiveness of Psychobiotics in the Treatment of Psychiatric and Cognitive Disorders: A Systematic Review of Randomized Clinical Trials

In this study, a systematic review of randomized clinical trials conducted from January 2000 to December 2023 was performed to examine the efficacy of psychobiotics-probiotics beneficial to mental health via the gut-brain axis-in adults with psychiatric and cognitive disorders. Out of the 51 studies involving 3353 patients where half received psychobiotics, there was a notably high measurement of effectiveness specifically in the treatment of depression symptoms. Most participants were older and female, with treatments commonly utilizing strains of Lactobacillus and Bifidobacteria over periods ranging from 4 to 24 weeks. Although there was a general agreement on the effectiveness of psychobiotics, the variability in treatment approaches and clinical presentations limits the comparability and generalization of the findings. This underscores the need for more personalized treatment optimization and a deeper investigation into the mechanisms through which psychobiotics act. The research corroborates the therapeutic potential of psychobiotics and represents progress in the management of psychiatric and cognitive disorders.

Bipolar disorder and the gut microbiota: a bibliometric analysis

Background

Previous studies have explored the relationship between bipolar disorder and gut microbiota. However, there has been no bibliometric analysis to summarize and analyze these publications. Our objective was to perform a bibliometric analysis to investigate the current status and frontiers of the publications in the field of the association between bipolar disorder and the gut microbiota.

Methods

We retrieved publications concerning the interplay between the gut microbiota and bipolar disorder from the Web of Science Core Collection (WoSCC). The analysis was executed using WoSCC's literature analysis tool and VOSviewer 1.6.16.

Results

In total, we identified 177 publications originating from 362 institutions across 39 countries/regions, and these articles were disseminated in 104 different journals. The most productive institutions, authors, countries/regions, and journals were Zhejiang University contributing 18 publications, Shaohua Hu authoring 12 publications, China with 53 publications, and Frontiers in Psychiatry with 11 publications. The first high-cited document was published in the Journal of Psychiatric Research in 2017, and authored by Evans. In this article, they found gut microbiome composition was associated with BD and its illness severity, and they concluded that targeting the gut microbiota may be helpful to develop the effective treatment for bipolar disorder. The top 5 keywords with the highest frequency except for bipolar disorder and gut microbiota were as follows: depression, inflammation, probiotic, gut-brain axis, and anxiety.

Conclusion

In conclusion, this is the first bibliometric analysis to explore the publications in the field of the association between bipolar disorder and the gut microbiota. The main research hotspots regarding this field were the characteristics, abundance, and diversity of gut microbiome in bipolar disorder, the role of treatment and gut microbiome in bipolar disorder, microbiome-brain connections in bipolar disorder, and interventions for bipolar disorder based on microbiota composition modification. The number of studies about the association between gut microbiota and bipolar disorder is relatively small, and more studies are needed to expand our understanding the association between gut microbiota and bipolar disorder.

Pathophysiology of acute lung injury in patients with acute brain injury: the triple-hit hypothesis

It has been convincingly demonstrated in recent years that isolated acute brain injury (ABI) may cause severe dysfunction of peripheral extracranial organs and systems. Of all potential target organs and systems, the lung appears to be the most vulnerable to damage after ABI. The pathophysiology of the bidirectional brain-lung interactions is multifactorial and involves inflammatory cascades, immune suppression, and dysfunction of the autonomic system. Indeed, the systemic effects of inflammatory mediators in patients with ABI create a systemic inflammatory environment ("first hit") that makes extracranial organs vulnerable to secondary procedures that enhance inflammation, such as mechanical ventilation (MV), surgery, and infections ("second hit"). Moreover, accumulating evidence supports the knowledge that gut microbiota constitutes a critical superorganism and an organ on its own, potentially modifying various physiological functions of the host. Furthermore, experimental and clinical data suggest the existence of a communication network among the brain, gastrointestinal tract, and its microbiome, which appears to regulate immune responses, gastrointestinal function, brain function, behavior, and stress responses, also named the "gut-microbiome-brain axis." Additionally, recent research evidence has highlighted a crucial interplay between the intestinal microbiota and the lungs, referred to as the "gut-lung axis," in which alterations during critical illness could result in bacterial translocation, sustained inflammation, lung injury, and pulmonary fibrosis. In the present work, we aimed to further elucidate the pathophysiology of acute lung injury (ALI) in patients with ABI by attempting to develop the "double-hit" theory, proposing the "triple-hit" hypothesis, focused on the influence of the gut-lung axis on the lung. Particularly, we propose, in addition to sympathetic hyperactivity, blast theory, and double-hit theory, that dysbiosis and intestinal dysfunction in the context of ABI alter the gut-lung axis, resulting in the development or further aggravation of existing ALI, which constitutes the "third hit."

Current Insights into the Use of Probiotics and Fatty Acids in Alleviating Depression

(1) Background: Depression is the most prevalent psychiatric symptom present among individuals of all ages and backgrounds, impacting an estimated 300 million people globally. Therefore, it demands a significant amount of attention when it comes to managing depression. A growing amount of data reveal that probiotics and fatty acids could be beneficial to depression. However, the opposing position maintains that they have no influence on depression. A network meta-analyses of existing datasets aid in the estimation of comparative efficacy as well as in achieving an understanding of the relative merits of different therapies. The purpose of this study was to investigate the current evidence for probiotic or fatty acid depression therapy and to establish a practical alternative for depression patients using a meta-analysis and metagenomic data from a Wistar-Kyoto (WKY) depressed rat model. (2) Methods: Probiotic data were obtained from seven randomized controlled trial studies (n = 394), and fatty acid data were obtained from 24 randomized controlled trial studies (n = 1876). Meanwhile, a metagenomics analysis of data on animal gut flora was also applied to validate the preceding evidence. (3) Results: The fatty acid studies were separated into three sections based on the duration of probiotic delivery: ≤8 weeks, 9-12 weeks, and >12 weeks. The results were as follows: for ≤8 weeks, MD = -1.65 (95% CI: -2.96--0.15), p = 0.01; for 9-12 weeks, MD = -2.22 (95% CI: -3.03--1.22), p < 0.001; for >12 weeks, MD = -1.23 (95% CI: -2.85-0.39), p = 0.14. Regarding the probiotics, the meta-analysis revealed MD = -2.19 (95% CI: -3.38--2.43), p < 0.001. The research presented herein illustrates that probiotics and fatty acids may successfully lower depression scores. Additionally, the probiotics were drastically reduced in the WKY rats. (4) Conclusions: According to the data, a depression intervention utilizing probiotics outperformed the control, implying that the use of probiotics and fatty acids may be a successful strategy for depression treatment.

The gut microbiota-brain axis in neurological disorder

The gut microbiota (GM) plays an important role in the physiology and pathology of the host. Microbiota communicate with different organs of the organism by synthesizing hormones and regulating body activity. The interaction of the central nervous system (CNS) and gut signaling pathways includes chemical, neural immune and endocrine routes. Alteration or dysbiosis in the gut microbiota leads to different gastrointestinal tract disorders that ultimately impact host physiology because of the abnormal microbial metabolites that stimulate and trigger different physiologic reactions in the host body. Intestinal dysbiosis leads to a change in the bidirectional relationship between the CNS and GM, which is linked to the pathogenesis of neurodevelopmental and neurological disorders. Increasing preclinical and clinical studies/evidence indicate that gut microbes are a possible susceptibility factor for the progression of neurological disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS) and autism spectrum disorder (ASD). In this review, we discuss the crucial connection between the gut microbiota and the central nervous system, the signaling pathways of multiple biological systems and the contribution of gut microbiota-related neurological disorders.

Association Between Gut Microbiota and Delirium in Acutely Ill Older Adults

Our aim was to investigate the association between gut microbiota and delirium occurrence in acutely ill older adults. We included 133 participants 65+ years consecutively admitted to the emergency department of a tertiary university hospital, between September 2019 and March 2020. We excluded candidates with ≥24-hour antibiotic utilization on admission, recent prebiotic or probiotic utilization, artificial nutrition, acute gastrointestinal disorders, severe traumatic brain injury, recent hospitalization, institutionalization, expected discharge ≤48 hours, or admission for end-of-life care. A trained research team followed a standardized interview protocol to collect sociodemographic, clinical, and laboratory data on admission and throughout the hospital stay. Our exposure measures were gut microbiota alpha and beta diversities, taxa relative abundance, and core microbiome. Our primary outcome was delirium, assessed twice daily using the Confusion Assessment Method. Delirium was detected in 38 participants (29%). We analyzed 257 swab samples. After adjusting for potential confounders, we observed that a greater alpha diversity (higher abundance and richness of microorganisms) was associated with a lower risk of delirium, as measured by the Shannon (odds ratio [OR] = 0.77; 95% confidence interval [CI] = 0.60-0.99; p = .042) and Pielou indexes (OR = 0.69; 95% CI = 0.51-0.87; p = .005). Bacterial taxa associated with pro-inflammatory pathways (Enterobacteriaceae) and modulation of relevant neurotransmitters (Serratia: dopamine; Bacteroides, Parabacteroides: GABA) were more common in participants with delirium. Gut microbiota diversity and composition were significantly different in acutely ill hospitalized older adults who experienced delirium. Our work is an original proof-of-concept investigation that lays a foundation for future biomarker studies and potential therapeutic targets for delirium prevention and treatment.

Is the Gut Microbiome Implicated in the Excess Risk of Hypertension Associated with Obstructive Sleep Apnea? A Contemporary Review

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder and an established risk factor for cardiovascular diseases, including hypertension. The pathogenesis of elevated blood pressure (BP) in OSA is multifactorial, including sympathetic overdrive, vascular aberrations, oxidative stress, inflammation, and metabolic dysregulation. Among the mechanisms potentially involved in OSA-induced hypertension, the role of the gut microbiome is gaining increasing attention. Perturbations in the diversity, composition, and function of the gut microbiota have been causally linked to numerous disorders, and robust evidence has identified gut dysbiosis as a determinant of BP elevation in various populations. In this brief review, we summarize the current body of literature on the implications of altered gut microbiota for hypertension risk in OSA. Data from both preclinical models of OSA and patient populations are presented, and potential mechanistic pathways are highlighted, along with therapeutic considerations. Available evidence suggests that gut dysbiosis may promote the development of hypertension in OSA and may thus be a target for interventions aimed at attenuating the adverse consequences of OSA in relation to cardiovascular risk.

The Microbiota-Gut-Brain Axis: Psychoneuroimmunological Insights

There is growing interest in the role that the intestinal microbiota and the related autoimmune processes may have in the genesis and presentation of some psychiatric diseases. An alteration in the communication of the microbiota-gut-brain axis, which constitutes a communicative model between the central nervous system (CNS) and the gastro-enteric tract, has been identified as one of the possible causes of some psychiatric diseases. The purpose of this narrative review is to describe evidence supporting a role of the gut microbiota in psychiatric diseases and the impact of diet on microbiota and mental health. Change in the composition of the gut microbiota could determine an increase in the permeability of the intestinal barrier, leading to a cytokine storm. This could trigger a systemic inflammatory activation and immune response: this series of events could have repercussions on the release of some neurotransmitters, altering the activity of the hypothalamic-pituitary-adrenal axis, and reducing the presence of trophic brain factors. Although gut microbiota and psychiatric disorders seem to be connected, more effort is needed to understand the potential causative mechanisms underlying the interactions between these systems.

The Role of Diet as a Modulator of the Inflammatory Process in the Neurological Diseases

Neurological diseases are recognized as major causes of disability and mortality worldwide. Due to the dynamic progress of diseases such as Alzheimer’s disease (AD), Parkinson’s Disease (PD), Schizophrenia, Depression, and Multiple Sclerosis (MD), scientists are mobilized to look for new and more effective methods of interventions. A growing body of evidence suggests that inflammatory processes and an imbalance in the composition and function of the gut microbiome, which play a critical role in the pathogenesis of various neurological diseases and dietary interventions, such as the Mediterranean diet the DASH diet, or the ketogenic diet can have beneficial effects on their course. The aim of this review was to take a closer look at the role of diet and its ingredients in modulating inflammation associated with the development and/or progression of central nervous system diseases. Presented data shows that consuming a diet abundant in fruits, vegetables, nuts, herbs, spices, and legumes that are sources of anti-inflammatory elements such as omega-3 fatty acids, polyphenols, vitamins, essential minerals, and probiotics while avoiding foods that promote inflammation, create a positive brain environment and is associated with a reduced risk of neurological diseases. Personalized nutritional interventions may constitute a non-invasive and effective strategy in combating neurological disorders.

Matrine alleviates depressive-like behaviors via modulating microbiota-gut-brain axis in CUMS-induced mice

BACKGROUND

The realization of the "microbiota-gut-brain" axis plays a critical role in neuropsychiatric disorders, particularly depression, is advancing rapidly. Matrine is a natural bioactive compound, which has been found to possess potential antidepressant effect. However, the underlying mechanisms of regulation of the "microbiota-gut-brain" axis in the treatment of depression by oral matrine remain elusive.

METHODS

Its antidepressant effects were initially evaluated by behavioral tests and relative levels of monoamine neurotransmitters, and matrine has been observed to attenuate the depression-like behavior and increase neurotransmitter content in CUMS-induced mice. Subsequently, studies from the "gut" to "brain" were conducted, including detection of the composition of gut microbiota by 16S rRNA sequencing; the metabolomics detection of gut metabolites and the analysis of differential metabolic pathways; the assessment of relative levels of diamine oxidase, lipopolysaccharide, pro-inflammatory cytokines, and brain-derived neurotrophic factor (BDNF) by ELISA kits or immunofluorescence.

RESULTS

Matrine could regulate the disturbance of gut microbiota and metabolites, restore intestinal permeability, and reduce intestinal inflammation, thereby reducing the levels of pro-inflammatory cytokines in peripheral blood circulation and brain regions, and ultimately increase the levels of BDNF in brain.

CONCLUSION

Matrine may ameliorate CUMS-induced depression in mice by modulating the "microbiota-gut-brain" axis.

Dietary Supplementation of Eubiotic Fiber Based on Lignocellulose on Performance and Welfare of Gestating and Lactating Sows

The present study aimed to evaluate the effects of partially fermentable insoluble dietary fiber supplementation on the behavior, surface temperature, and reproductive parameters of gestating and lactating sows, as well as on the performance of their litters. Four hundred hyper-prolific sows were assigned in a randomized block design with two treatment groups during the gestation phase: Control (C), corn-soy based diets, or corn-soy based diets with daily 55 g supplementation of eubiotic fiber (F) from the 85th day of gestation until the farrowing (late pregnancy). During the lactation phase, the sows were assigned in a 2 × 2 factorial design using the following treatment groups: (1) CC, no fiber included during gestation and lactation. (2) FC, daily inclusion of 55 g of fiber only during late pregnancy. (3) CF, daily inclusion of 55 g of fiber only during lactation. (4) FF, daily inclusion of 55 g of fiber during late pregnancy and lactation. Sows that received dietary fiber supplementation during the final third of gestation increased feed intake during lactation. Piglets from sows supplemented in both phases showed a significant increase in weight at weaning. The dietary supplementation of eubiotic fiber for sows in the end period of gestation and lactation improved performance and welfare, with positive consequences for developing their litters.

Microbiota-Gut-Brain Axis in Major Depression: A New Therapeutic Approach

Major depression is impacted by the disruption of gut microbiota. Defects in gut microbiota can lead to microbiota-gut-brain axis dysfunction and increased vulnerability to major depression. While traditional chemotherapeutic approaches, such as antidepressant use, produce an overall partial therapeutic effect on depression, the gut microbiome has emerged as an effective target for better therapeutic outcomes. Recent representative studies on the microbiota hypothesis to explore the association between gut pathophysiology and major depression have indicated that restoring gut microbiota and microbiota-gut-brain axis could alleviate depression. We reviewed studies that supported the gut microbiota hypothesis to better understand the pathophysiology of depression; we also explored reports suggesting that gut microbiota restoration is an effective approach for improving depression. These findings indicate that gut microbiota and microbiota-gut-brain axis are appropriate new therapeutic targets for major depression.

Antibiotic use and the development of depression: A systematic review

OBJECTIVE

Increasingly, disruption of the gastrointestinal ecosystem is thought to be involved in the pathogenesis of several medical conditions, including depression. Antibiotics can induce substantial changes in the gastrointestinal microbiota and several lines of evidence suggest that antibiotics exposure may increase the risk of developing depression. This systematic review examined this potential association.

METHODS

PubMed, Ovid EMBASE, CINAHL, and PsychINFO databases, as well as unpublished resources, were searched for studies in humans published from 2000 onwards. The studies needed to consider the connection between antibiotic exposure (either alone or in combination with other antibiotics and medications) and the development of depressive symptoms and/or disorders (in isolation to other psychological conditions).

RESULTS

Nine studies met the eligibility criteria. All were observational in nature. The studies were conducted in different age groups with various indications for receiving antibiotics. Together, these relatively low-quality studies suggest a potential association between antibiotic exposure and subsequent development of depression symptoms. Specifically, studies from the United Kingdom and Sweden indicate that the risk of depression is increased by at least 20%, with the former (over 1 million participants) reporting an increased risk with the number of courses and agents used, that persists with a slow decline over the ten years following exposure.

CONCLUSIONS

The inherent limitations associated with the studies' methodologies make a reliable conclusion difficult. While the risk of antimicrobial resistance may prohibit large randomised clinical trials in healthy individuals, future placebo-controlled trials with antibiotics-based protocols (e.g. for acne) should explore their effect on mental health.

An exploratory study of the gut microbiota in major depression with anxious distress

OBJECTIVES

To explore differences in the diversity and composition of the gut microbiome between major depressive disorder (MDD) with and without anxious distress.

METHODS

The study comprised 117 participants (79 female, 36 male, 2 other, mean age 38.2 ± 13.4 years) with a current major depressive episode (MDE) with (n = 63) and without (n = 54) the anxious distress specifier. A clinical psychologist administered the structured clinical interview for the DSM-5-RV to confirm a diagnosis of depression. Participants provided stool samples which were immediately frozen and stored at -80 °C. These samples were analysed using the Illumina 16S Metagenomics sequencing protocol in which the sequencing primers target the V3 and V4 regions of the 16S rRNA gene. Participants also completed mental health questionnaires to assess severity of depression (BDI-II), generalized anxiety (GAD-7), and stress (PSS).

RESULTS

There were no significant group differences in α-diversity (Shannon's diversity Index; Simpson Index), richness (ACE; Chao1), (Pielou's) evenness, or beta diversity (Bray-Curtis dissimilarity index and weighted UniFrac distance) of gut bacteria. Significant group differences in the relative abundance of gut microbiota however were observed at each taxonomical level, including across 15 genera and 18 species.

LIMITATIONS

This was an exploratory study that needs to be replicated across larger samples and compared with a healthy control group.

CONCLUSIONS

The research contributes to knowledge of the depressive gut microbial profile unique to the anxious distress subtype of MDD.

Leaky Gut Plays a Critical Role in the Pathophysiology of Autism in Mice by Activating the Lipopolysaccharide-Mediated Toll-Like Receptor 4–Myeloid Differentiation Factor 88–Nuclear Factor Kappa B Signaling Pathway

Increased intestinal barrier permeability, leaky gut, has been reported in patients with autism. However, its contribution to the development of autism has not been determined. We selected dextran sulfate sodium (DSS) to disrupt and metformin to repair the intestinal barrier in BTBR T+tf/J autistic mice to test this hypothesis. DSS treatment resulted in a decreased affinity for social proximity; however, autistic behaviors in mice were improved after the administration of metformin. We found an increased affinity for social proximity/social memory and decreased repetitive and anxiety-related behaviors. The concentration of lipopolysaccharides in blood decreased after the administration of metformin. The expression levels of the key molecules in the toll-like receptor 4 (TLR4)–myeloid differentiation factor 88 (MyD88)–nuclear factor kappa B (NF-κB) pathway and their downstream inflammatory cytokines in the cerebral cortex were both repressed. Thus, “leaky gut” could be a trigger for the development of autism via activation of the lipopolysaccharide-mediated TLR4–MyD88–NF-κB pathway.

The Microbiota–Gut–Brain Axis in Psychiatric Disorders

Modulating the gut microbiome and its influence on human health is the subject of intense research. The gut microbiota could be associated not only with gastroenterological diseases but also with psychiatric disorders. The importance of factors such as stress, mode of delivery, the role of probiotics, circadian clock system, diet, and occupational and environmental exposure in the relationship between the gut microbiota and brain function through bidirectional communication, described as “the microbiome–gut–brain axis”, is especially underlined. In this review, we discuss the link between the intestinal microbiome and the brain and host response involving different pathways between the intestinal microbiota and the nervous system (e.g., neurotransmitters, endocrine system, immunological mechanisms, or bacterial metabolites). We review the microbiota alterations and their results in the development of psychiatric disorders, including major depressive disorder (MDD), schizophrenia (SCZ), bipolar disorder (BD), autism spectrum disorder (ASD), and attention-deficit hyperactivity disorder (ADHD).

Randomized Double-Blind Crossover Study for Evaluating a Probiotic Mixture on Gastrointestinal and Behavioral Symptoms of Autistic Children

Autism spectrum disorders (ASDs) represent a diagnostic challenge with a still partially uncertain etiology, in which genetic and environmental factors have now been assessed. Among the hypotheses underlying the involvement of biological and environmental factors, the gut–brain axis is of particular interest in autism spectrum disorders. Several studies have highlighted the related incidence of particular gastrointestinal symptoms (GISs) in children suffering from ASDs. Probiotics have shown success in treating several gastrointestinal dysbiotic disorders; therefore, it is plausible to investigate whether they can alleviate behavioral symptoms as well. On these bases, a randomized double-blind crossover study with a placebo was conducted, evaluating the effects of a mixture of probiotics in a group of 61 subjects aged between 24 months and 16 years old with a diagnosis of ASD. Behavioral evaluation was performed through the administration of a questionnaire including a Parenting Stress Index (PSI) test and the Vineland Adaptive Behavior Scale (VABS). The Psycho-Educational Profile and the Autism Spectrum Rating Scale (ASRS) were also evaluated. Microbial composition analyses of fecal samples of the two groups was also performed. The study showed significant improvements in GISs, communication skills, maladaptive behaviors, and perceived parental stress level after the administration of probiotics. Microbiome alpha diversity was comparable between treatment arms and no significant differences were found, although beta diversity results were significantly different in the treatment group between T0 and T1 time points. Streptococcus thermophilus, Bifidobacterium longum, Limosilactobacillus fermentum, and Ligilactobacillus salivarius species were identified as some of the most discriminant taxa positively associated with T1 samples. This preliminary study corroborates the relationship between intestinal microbiota and ASD recently described in the literature.

The Endocannabinoids-Microbiota Partnership in Gut-Brain Axis Homeostasis: Implications for Autism Spectrum Disorders

The latest years have witnessed a growing interest towards the relationship between neuropsychiatric disease in children with autism spectrum disorders (ASD) and severe alterations in gut microbiota composition. In parallel, an increasing literature has focused the attention towards the association between derangement of the endocannabinoids machinery and some mechanisms and symptoms identified in ASD pathophysiology, such as alteration of neural development, immune system dysfunction, defective social interaction and stereotypic behavior. In this narrative review, we put together the vast ground of endocannabinoids and their partnership with gut microbiota, pursuing the hypothesis that the crosstalk between these two complex homeostatic systems (bioactive lipid mediators, receptors, biosynthetic and hydrolytic enzymes and the entire bacterial gut ecosystem, signaling molecules, metabolites and short chain fatty acids) may disclose new ideas and functional connections for the development of synergic treatments combining “gut-therapy,” nutritional intervention and pharmacological approaches. The two separate domains of the literature have been examined looking for all the plausible (and so far known) overlapping points, describing the mutual changes induced by acting either on the endocannabinoid system or on gut bacteria population and their relevance for the understanding of ASD pathophysiology. Both human pathology and symptoms relief in ASD subjects, as well as multiple ASD-like animal models, have been taken into consideration in order to provide evidence of the relevance of the endocannabinoids-microbiota crosstalk in this major neurodevelopmental disorder.

Guts Imbalance Imbalances the Brain: A Review of Gut Microbiota Association With Neurological and Psychiatric Disorders

Over the last 10 years, there has been a growing interest in the relationship between gut microbiota, the brain, and neurologic-associated affections. As multiple preclinical and clinical research studies highlight gut microbiota’s potential to modulate the general state of health state, it goes without saying that gut microbiota plays a significant role in neurogenesis, mental and cognitive development, emotions, and behaviors, and in the progression of neuropsychiatric illnesses. Gut microbiota produces important biologic products that, through the gut-brain axis, are directly connected with the appearance and evolution of neurological and psychiatric disorders such as depression, anxiety, bipolar disorder, autism, schizophrenia, Parkinson’s disease, Alzheimer’s disease, dementia, multiple sclerosis, and epilepsy. This study reviews recent research on the link between gut microbiota and the brain, and microbiome’s role in shaping the development of the most common neurological and psychiatric illnesses. Moreover, special attention is paid to the use of probiotic formulations as a potential non-invasive therapeutic opportunity for prevention and management of neuropsychiatric-associated affections.

The Role of Gut Microbiota in Gastrointestinal Tract Cancers

Disturbances in gastrointestinal (GI) microbiota could play a significant role in the development of GI cancers, but the underlying mechanisms remain largely unclear. While some bacteria seem to facilitate carcinogenesis, others appear to be protective. So far only one bacterium (Helicobacter pylori) has been classified by the International Agency for Cancer Research as carcinogenic in humans but many other are the subject of intense research. Most studies on the role of microbiota in GI tract oncogenesis focus on pancreatic and colorectal cancers with the following three species: Helicobacter pylori, Escherichia coli, and Porphyromonas gingivalis as likely causative factors. This review summarizes the role of bacteria in GI tract oncogenesis.

Mutual Links between the Endocannabinoidome and the Gut Microbiome, with Special Reference to Companion Animals: A Nutritional Viewpoint

There is growing evidence that perturbation of the gut microbiome, known as “dysbiosis”, is associated with the pathogenesis of human and veterinary diseases that are not restricted to the gastrointestinal tract. In this regard, recent studies have demonstrated that dysbiosis is linked to the pathogenesis of central neuroinflammatory disorders, supporting the existence of the so-called microbiome-gut-brain axis. The endocannabinoid system is a recently recognized lipid signaling system and termed endocannabinoidome monitoring a variety of body responses. Accumulating evidence demonstrates that a profound link exists between the gut microbiome and the endocannabinoidome, with mutual interactions controlling intestinal homeostasis, energy metabolism and neuroinflammatory responses during physiological conditions. In the present review, we summarize the latest data on the microbiome-endocannabinoidome mutual link in health and disease, focalizing the attention on gut dysbiosis and/or altered endocannabinoidome tone that may distort the bidirectional crosstalk between these two complex systems, thus leading to gastrointestinal and metabolic diseases (e.g., idiopathic inflammation, chronic enteropathies and obesity) as well as neuroinflammatory disorders (e.g., neuropathic pain and depression). We also briefly discuss the novel possible dietary interventions based not only on probiotics and/or prebiotics, but also, and most importantly, on endocannabinoid-like modulators (e.g., palmitoylethanolamide) for intestinal health and beyond.

Current Knowledge About the Implication of Bacterial Microbiota in Human Health and Disease

Recent advances in molecular genetics and the invention of new technologies led to a development in our knowledge about human microbiota, specifically bacterial one. The microbiota plays a fundamental role in the immunologic, hormonal and metabolic homeostasis of the host. After the initiation of the Human Microbiome Project, it became clear that the human microbiota consists of the 10-100 trillion symbiotic microbial cells harbored by each person, primarily bacteria in the gut, but also in other spots as the skin, mouth, nose, and vagina. Despite of the differences in studying bacterial species, decreased bacterial diversity and persistence has been connected with several diverse human diseases primarily diabetes, IBD (inflammatory bowel disease) and others; attempts were made even to explain psychiatric pathology. Several species emerged as dominant and were clearly linked to certain disorders or accepted as biomarkers of others. The current review aims to discuss key issues of our current knowledge about bacteria in human, the difficulties and methods of its analysis, its contribution to human health and responsibility for human diseases.

Antibiotics Treatment Modulates Microglia-Synapses Interaction

‘Dysbiosis’ of the adult gut microbiota, in response to challenges such as infection, altered diet, stress, and antibiotics treatment has been recently linked to pathological alteration of brain function and behavior. Moreover, gut microbiota composition constantly controls microglia maturation, as revealed by morphological observations and gene expression analysis. However, it is unclear whether microglia functional properties and crosstalk with neurons, known to shape and modulate synaptic development and function, are influenced by the gut microbiota. Here, we investigated how antibiotic-mediated alteration of the gut microbiota influences microglial and neuronal functions in adult mice hippocampus. Hippocampal microglia from adult mice treated with oral antibiotics exhibited increased microglia density, altered basal patrolling activity, and impaired process rearrangement in response to damage. Patch clamp recordings at CA3-CA1 synapses revealed that antibiotics treatment alters neuronal functions, reducing spontaneous postsynaptic glutamatergic currents and decreasing synaptic connectivity, without reducing dendritic spines density. Antibiotics treatment was unable to modulate synaptic function in CX3CR1-deficient mice, pointing to an involvement of microglia–neuron crosstalk through the CX3CL1/CX3CR1 axis in the effect of dysbiosis on neuronal functions. Together, our findings show that antibiotic alteration of gut microbiota impairs synaptic efficacy, suggesting that CX3CL1/CX3CR1 signaling supporting microglia is a major player in in the gut–brain axis, and in particular in the gut microbiota-to-neuron communication pathway.

The role of microbiota-gut-brain axis in neuropsychiatric and neurological disorders

Emerging evidence indicates that the gut microbiota play a crucial role in the bidirectional communication between the gut and the brain suggesting that the gut microbes may shape neural development, modulate neurotransmission and affect behavior, and thereby contribute to the pathogenesis and/or progression of many neurodevelopmental, neuropsychiatric, and neurological conditions. This review summarizes recent data on the role of microbiota-gut-brain axis in the pathophysiology of neuropsychiatric and neurological disorders including depression, anxiety, schizophrenia, autism spectrum disorders, Parkinson's disease, migraine, and epilepsy. Also, the involvement of microbiota in gut disorders co-existing with neuropsychiatric conditions is highlighted. We discuss data from both in vivo preclinical experiments and clinical reports including: (1) studies in germ-free animals, (2) studies exploring the gut microbiota composition in animal models of diseases or in humans, (3) studies evaluating the effects of probiotic, prebiotic or antibiotic treatment as well as (4) the effects of fecal microbiota transplantation.

Gut microbiota alteration and modulation in psychiatric disorders: Current evidence on fecal microbiota transplantation

The micro-organisms residing within the gastrointestinal tract, namely gut microbiota, form a dynamic population proper of each individual, mostly composed by bacteria which co-evolved symbiotically with human species. The advances of culture-independent techniques allowed the understanding of the multiple functions of the gut microbiota in human physiology and disease, the latter often recognising a predisposing condition in an imbalanced intestinal microbial ecosystem (dysbiosis). A complex mutual interconnection between the central nervous system (CNS), the intestine and the gut microbiota, known as "microbiota-gut-brain axis", has been hypothesized to play a pivotal role in maintaining central and peripheral functions, as well as mental health. Thus, dysbiosis with specific microbiota imbalances seems to be strongly associated with the onset psychiatric disorders by altering neurodevelopment, enhancing neurodegeneration, affecting behaviour and mood. Fecal microbiota transplantation (FMT) consists of transferring the fecal matter from a donor into the gastrointestinal tract of a recipient, and it is used to quickly modulate the gut microbiota. This review focuses on the uses of FMT in psychiatric disorders. FMT has been used to induce dysbiosis and to study the disease development, or to heal dysbiosis-related mental disorders. Overall, FMT of impaired microbiota resulted effective in enhancing psychiatric-like disturbances (mainly depression and anxiety) in recipient animals, plausibly by impairing immune system, inflammatory and metabolic pathways, neurochemical processes and neuro-transmission. On the other side, preclinical and clinical data suggest that reversing or mitigating dysbiosis seems a promising strategy to restore behavioural impairments or to obtain psychiatric symptom relief. However, current evidence is limited by the lack of procedural standardization, the paucity of human studies in the vastity of psychiatric conditions and the need of a microbiota-targeted donor-recipient matching.

The interaction between tea polyphenols and host intestinal microorganisms: an effective way to prevent psychiatric disorders

Tea polyphenols (TP) are the most bioactive components in tea extracts. It has been reported that TP can regulate the composition and the function of the intestinal flora. Meanwhile, intestinal microorganisms improve the bioavailability of TP, and the corresponding metabolites of TP can regulate intestinal micro-ecology and promote human health more effectively. The dysfunction of the microbiota-gut-brain axis is the main pathological basis of depression, and its abnormality may be the direct cause and potential influencing factor of psychiatric disorders. The interrelationship between TP and intestinal microorganisms is discussed in this review, which will enable us to better evaluate the potential preventive effects of TP on psychiatric disorders by modulating host intestinal microorganisms.

Intestinal changes associated with fluoride exposure in rats: Integrative morphological, proteomic and microbiome analyses

Gastrointestinal signs and symptoms are the first signs of toxicity due to exposure to fluoride (F). This suggests the possibility that lower levels of subchronic F exposure may affect the gut. The aim of this study was to evaluate changes in the morphology, proteome and microbiome of the ileum of rats, after subchronic exposure to F. Male rats ingested water with 0, 10, or 50 mgF/L for thirty days. Treatment with F, regardless of the dose, significantly decreased the density of HuC/D-IR neurons, whereas CGRP-IR and SP-IR varicosities were significantly increased compared to the control group. Increased VIP-IR varicosities were significantly increased only in the group treated with 50 mgF/L. A significant increase in thickness of the tunica muscularis, as well as in the total thickness of the ileum wall was observed at both F doses when compared to controls. In proteomics analysis, myosin isoforms were increased, and Gastrotopin was decreased in F-exposed mice. In the microbiome metagenomics analysis, Class Clostridia was significantly reduced upon exposure to 10 mgF/L. At the higher F dose of 50 mg/L, genus Ureaplasma was significantly reduced in comparison with controls. Morphological and proteomics alterations induced by F were marked by changes associated with inflammation, and alterations in the gut microbiome. Further studies are needed to determine whether F exposure increases inflammation with secondary effects of the gut microbiome, and/or whether primary effects of F on the gut microbiome enhance changes associated with inflammation.

The role of the intestinal microbiota in eating disorders - bulimia nervosa and binge eating disorder

Bulimia nervosa (BN) and binge eating disorder (BED) are both eating disorders (EDs) characterised by episodes of overeating in which large amounts of food are consumed in short periods. The aetiology of BN and BED is not fully understood. Psychological and social factors influence the development of BN and BED, but biological factors such as neurohormones that regulate hunger and satiety, or neurotransmitters responsible for mood and anxiety play a significant role in sustaining symptoms. Increasing numbers of studies confirm the relationship between the composition of intestinal microbiota and the regulation of appetite, mood, and body mass. In this manuscript, we will describe the mechanisms by which intestinal dysbiosis can play an important role in the aetiology of binge eating episodes based on current understanding. Understanding the two-way relationship between BN and BED and alterations in the intestinal microbiota suggest the utility of new treatment methods of these disorders aimed at improving the composition of the intestinal microflora.

Gut microbiota in mental health and depression: role of pre/pro/synbiotics in their modulation

The microbiome residing in the human gut performs a wide range of biological functions. Recently, it has been elucidated that a change in dietary habits is associated with alteration in the gut microflora which results in increased health risks and vulnerability towards various diseases. Falling in line with the same concept, depression has also been shown to increase its prevalence around the globe, especially in the western world. Various research studies have suggested that changes in the gut microbiome profile further result in decreased tolerance of stress. Although currently available medications help in relieving the symptoms of depressive disorders briefly, these drugs are not able to completely reverse the multifactorial pathology of depression. The discovery of the communication pathway between gut microbes and the brain, i.e. the Gut-Brain Axis, has led to new areas of research to find more effective and safer alternatives to current antidepressants. The use of probiotics and prebiotics has been suggested as being effective in various preclinical studies and clinical trials for depression. Therefore, in the present review, we address the new antidepressant mechanisms via gut microbe alterations and provide insight into how these can provide an alternative to antidepressant therapy without the side effects and risk of adverse drug reactions.

The Neuroimmune Role of Intestinal Microbiota in the Pathogenesis of Cardiovascular Disease

Currently, a bidirectional relationship between the gut microbiota and the nervous system, which is considered as microbiota-gut-brain axis, is being actively studied. This axis is believed to be a key mechanism in the formation of somatovisceral functions in the human body. The gut microbiota determines the level of activation of the hypothalamic-pituitary system. In particular, the intestinal microbiota is an important source of neuroimmune mediators in the pathogenesis of cardiovascular disease. This review reflects the current state of publications in PubMed and Scopus databases until December 2020 on the mechanisms of formation and participation of neuroimmune mediators associated with gut microbiota in the development of cardiovascular disease.

Gut Microbiota and Bipolar Disorder: An Overview on a Novel Biomarker for Diagnosis and Treatment

The gut microbiota is the set of microorganisms that colonize the gastrointestinal tract of living creatures, establishing a bidirectional symbiotic relationship that is essential for maintaining homeostasis, for their growth and digestive processes. Growing evidence supports its involvement in the intercommunication system between the gut and the brain, so that it is called the gut-brain-microbiota axis. It is involved in the regulation of the functions of the Central Nervous System (CNS), behavior, mood and anxiety and, therefore, its implication in the pathogenesis of neuropsychiatric disorders. In this paper, we focused on the possible correlations between the gut microbiota and Bipolar Disorder (BD), in order to determine its role in the pathogenesis and in the clinical management of BD. Current literature supports a possible relationship between the compositional alterations of the intestinal microbiota and BD. Moreover, due to its impact on psychopharmacological treatment absorption, by acting on the composition of the microbiota beneficial effects can be obtained on BD symptoms. Finally, we discussed the potential of correcting gut microbiota alteration as a novel augmentation strategy in BD. Future studies are necessary to better clarify the relevance of gut microbiota alterations as state and disease biomarkers of BD.

Rebuilding Microbiome for Mitigating Traumatic Brain Injury: Importance of Restructuring the Gut-Microbiome-Brain Axis

Traumatic brain injury (TBI) is a damage to the brain from an external force that results in temporary or permanent impairment in brain functions. Unfortunately, not many treatment options are available to TBI patients. Therefore, knowledge of the complex interplay between gut microbiome (GM) and brain health may shed novel insights as it is a rapidly expanding field of research around the world. Recent studies show that GM plays important roles in shaping neurogenerative processes such as blood-brain-barrier (BBB), myelination, neurogenesis, and microglial maturation. In addition, GM is also known to modulate many aspects of neurological behavior and cognition; however, not much is known about the role of GM in brain injuries. Since GM has been shown to improve cellular and molecular functions via mitigating TBI-induced pathologies such as BBB permeability, neuroinflammation, astroglia activation, and mitochondrial dysfunction, herein we discuss how a dysbiotic gut environment, which in fact, contributes to central nervous system (CNS) disorders during brain injury and how to potentially ward off these harmful effects. We further opine that a better understanding of GM-brain (GMB) axis could help assist in designing better treatment and management strategies in future for the patients who are faced with limited options.

Gut Microbiota: the Emerging Link to Lung Homeostasis and Disease

The gut microbiota plays a crucial role in the development of the immune system and confers benefits or disease susceptibility to the host. Emerging studies have indicated the gut microbiota could affect pulmonary health and disease through cross talk between the gut microbiota and the lungs. Gut microbiota dysbiosis could lead to acute or chronic lung disease, such as asthma, tuberculosis, and lung cancer. In addition, the composition of the gut microbiota may be associated with different lung diseases, the prevalence of which also varies by age. Modulation of the gut microbiota through short-chain fatty acids, probiotics, and micronutrients may present potential therapeutic strategies to protect against lung diseases. In this review, we will provide an overview of the cross-talk between the gut microbiota and the lungs, as well as elucidate the underlying pathogenesis and/or potential therapeutic strategies of some lung diseases from the point of view of the gut microbiota.

Bifidobacterium animalis subsp. lactis BB-12 Improves the State Anxiety and Sports Performance of Young Divers Under Stress Situations: A Single-Arm, Prospective Proof-of-Concept Study

Background

Athletes will increase their state anxiety under stress situations, which will lead to the decline of sports performance. The improvement of anxiety by probiotics has been reported, but there is a lack of research in the athlete population. The purpose of the current study is to explore the effectiveness of probiotics in improving athletes' state anxiety and sports performance under stress situations.

Methods

We conducted this single-arm study in Chongqing Institute of Sports Technology. In the 8-week study, 21 Chongqing young divers (mean age: 9.10 ± 1.80) were given probiotic Bifidobacterium animalis subsp. lactis BB-12 (1 × 10⁹ colony-forming units/100 g) daily. The state anxiety and sports performance of athletes were measured before, during, and after the intervention, and the gut microbiota of athletes was measured before and after the intervention.

Results

The intervention results showed that cognitive state anxiety, somatic state anxiety, and anxiety emotion were improved (cognitive: Z = -3.964, P < 0.001; somatic: Z = -3.079, P = 0.003; anxiety: Z = -2.973, P < 0.001). In terms of gut microbiota, the intervention did not change the gut microbial composition (such as α diversity and β diversity) but increased the abundance of Bifidobacteriaceae. At the 8th week, the performance of athletes under stress was significantly improved (χ² = 7.88, P = 0.019).

Limitations

First of all, due to the restriction of the number of subjects in this study, there was no control group. Secondly, although the athletes' diet was recorded in this study, the influence of this factor on gut microbiota was not eliminated. Finally, the anxiety level of the athletes in this study was obtained through a self-report, lacking physiological data in state anxiety.

Conclusion

The results show that probiotics intervention can improve the state anxiety of athletes under stress situation and improve the performance of athletes under stress situation.

Intermittent Fasting, Dietary Modifications, and Exercise for the Control of Gestational Diabetes and Maternal Mood Dysregulation: A Review and a Case Report

Gestational diabetes mellitus (GDM) is a common pregnancy-related condition afflicting 5-36% of pregnancies. It is associated with many morbid maternal and fetal outcomes. Mood dysregulations (MDs, e.g., depression, distress, and anxiety) are common among women with GDM, and they exacerbate its prognosis and hinder its treatment. Hence, in addition to early detection and proper management of GDM, treating the associated MDs is crucial. Maternal hyperglycemia and MDs result from a complex network of genetic, behavioral, and environmental factors. This review briefly explores mechanisms that underlie GDM and prenatal MDs. It also describes the effect of exercise, dietary modification, and intermittent fasting (IF) on metabolic and affective dysfunctions exemplified by a case report. In this patient, interventions such as IF considerably reduced maternal body weight, plasma glucose, and psychological distress without any adverse effects. Thus, IF is one measure that can control GDM and maternal MDs; however, more investigations are warranted.

Adiponectin Role in Neurodegenerative Diseases: Focus on Nutrition Review

Adiponectin is an adipokine produced by adipose tissue. It has numerous beneficial effects. In particular, it improves metabolic effects and glucose homeostasis, lipid profile, and is involved in the regulation of cytokine profile and immune cell production, having anti-inflammatory and immune-regulatory effects. Adiponectin’s role is already known in immune diseases and also in neurodegenerative diseases. Neurodegenerative diseases, such as Alzheimer’s disease and Parkinson’s disease, are a set of diseases of the central nervous system, characterized by a chronic and selective process of neuron cell death, which occurs mainly in relation to oxidative stress and neuroinflammation. Lifestyle is able to influence the development of these diseases. In particular, unhealthy nutrition on gut microbiota, influences its composition and predisposition to develop many diseases such as neurodegenerative diseases, given the importance of the “gut-brain” axis. There is a strong interplay between Adiponectin, gut microbiota, and brain-gut axis. For these reasons, a healthy diet composed of healthy nutrients such as probiotics, prebiotics, polyphenols, can prevent many metabolic and inflammatory diseases such as neurodegenerative diseases and obesity. The special Adiponectin role should be taken into account also, in order to be able to use this component as a therapeutic molecule.

O eixo intestino-cérebro e sintomas depressivos: uma revisão sistemática dos ensaios clínicos randomizados com probióticos

RESUMO Objetivo: Reconhece-se atualmente a relevância do eixo intestino-cérebro para a compreensão de comportamentos e doenças mentais ou psiquiátricas. O presente estudo teve por objetivo analisar os efeitos do consumo de probióticos sobre sintomas depressivos e depressão maior. Métodos: O presente estudo constitui uma revisão de ensaios clínicos randomizados duplos-cegos ou triplos-cegos, placebo-controlados, publicados entre 2010 e 2020. Foi realizada busca por artigos nas bases de dados PubMed, ScienceDirect e Google Scholar. Resultados: Oito artigos compuseram a amostra do presente estudo. Os resultados entre estudos são controversos e indicam que a relação de causalidade entre o consumo de probióticos e o alívio de sintomas depressivos ainda não foi estabelecida. Conclusões: Mais ensaios clínicos randomizados duplos-cegos ou triplos-cegos, placebo-controlados, que controlem potenciais fatores de confusão (p. ex.: dieta, uso de antibióticos), são necessários para verificar consistentemente a relação causal entre o consumo de probióticos e o alívio de sintomas depressivos.

Vitamin D and Depression in Women: A Mini-review

Affective-related disorders, including depression, are constantly rising, complicating people’s personal lifestyle increasing disqualification and hospital care. Because of the high intensity of urbanization, our lifestyle and food have altered dramatically in the last twenty years. These food modifications have been associated with scores of depression and other affective-related disorders in urbanized countries with high economic levels. Nutrients imbalance is considered as one of the critical causes enabling the pathophysiological mechanisms for the development of psychiatric disorders. The application of additional nutritional interventions for treatment of mood deteriorations can be beneficial for both the prophylaxis and therapy of affective-related disorders. This paper will review recent research on the relation of Vitamin D levels and the epidemiology of depression in women.

In this paper, we will provide an overview of the results of a variety of different studies taking into account research which both suggests and refutes an association. Based on these findings we will propose important directions for future research in relation to this topic.

Evaluation of antibiotic-induced behavioral changes in mice

Gut microbiota (GM) plays a critical role in health maintenance. Previous reports connected GM with metabolic, immunologic and neurologic pathways. The main purpose of the current investigation was to study whether antibiotic-induced disturbances of GM affects psychological or behavioral conditions on mice as animal model. Mice were exposed to clindamycin or amoxicillin, and their behaviors were evaluated. Antibiotic-treated groups displayed reduced recognition memory and increased depression. No significant changes in the locomotor activity and anxiety were observed. Our data suggested that changes in GM composition by antibiotics may lead to the cognitive and behavioral deficit.

Efficacy of probiotics on stress in healthy volunteers: A systematic review and meta-analysis based on randomized controlled trials

BACKGROUND

Probiotics seems to play a beneficial role in stressed populations; thus, a systematic review and meta-analysis to assess the effects of probiotics on stress in healthy subjects were conducted.

METHODS

Randomized controlled trials on the effects of probiotics on stress in healthy subjects were retrieved from five databases. The effects of probiotics on subjective stress level, stress-related subthreshold anxiety/depression level, cortisol level, and adverse reactions were analyzed. Separate subgroup analyses were conducted on single-strain probiotics versus multi-strain probiotics, and short-term administration versus long-term administration.

RESULTS

Seven studies were included, involving a total of 1,146 subjects. All the studies were rated as low or moderate risk of bias. Our research found that probiotic administration can generally reduce the subjective stress level of healthy volunteers and may improve their stress-related subthreshold anxiety/depression level, but no significant effect was observed in the subgroup analysis. The effect of probiotics on cortisol level was not significant. Adverse reactions were reported in only one of seven studies, but left undescribed.

CONCLUSION

Current evidence suggests that probiotics can reduce subjective stress level in healthy volunteers and may alleviate stress-related subthreshold anxiety/depression level, without significant effect on cortisol level, and there is not enough support to draw conclusions about adverse effects; thus, more reliable evidence from clinical trials is needed.

Alteration of Gut Microbiota in Autism Spectrum Disorder: An Overview

The microbiota-gut-brain axis, which refers to the bidirectional communication pathway between gut bacteria and the central nervous system, has a profound effect on important brain processes, from the synthesis of neurotransmitters to the modulation of complex behaviors such as sociability and anxiety. Previous studies have revealed that the gut microbiota is potentially related to not only gastrointestinal disturbances, but also social impairment and repetitive behavior-core symptoms of autism spectrum disorder (ASD). Although studies have been conducted to characterize the microbial composition in patients with ASD, the results are heterogeneous. Nevertheless, it is clear that there is a difference in the composition of the gut microbiota between ASD and typically developed individuals, and animal studies have repeatedly suggested that the gut microbiota plays an important role in ASD pathophysiology. This possibility is supported by abnormalities in metabolites produced by the gut microbiota and the association between altered immune responses and the gut microbiota observed in ASD patients. Based on these findings, various attempts have been made to use the microbiota in ASD treatment. The results reported to date suggest that microbiota-based therapies may be effective for ASD, but largescale, well-designed studies are needed to confirm this.

Development of the Korean Form of the Premonitory Urge for Tics Scale: A Reliability and Validity Study

Objectives

This study aimed to evaluate the reliability and validity of the Korean Form of the Premonitory Urge for Tics Scale (K-PUTS).

Methods

Thirty-eight patients with Tourette's disorder who visited Jeonbuk National University Hospital were assessed with the K-PUTS. Together with the PUTS, the Yale Global Tic Severity Scale (YGTSS), the Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS), the attention-deficit/hyperactivity disorder (ADHD) rating scale (ARS), and the Adult ADHD Self-Report Scale (ASRS) were implemented to evaluate concurrent and discriminant validity.

Results

The internal consistency of items on the PUTS was high, with a Cronbach's α of 0.79. The test-retest reliability of the PUTS, which was administered at 2 weeks to 2 months intervals, showed high reliability with a Pearson correlation coefficient of 0.60. There was a significant positive correlation between the overall PUTS score and the YGTSS score, showing concurrent validity. There was no correlation between the PUTS, CY-BOCS, and ASRS scores, demonstrating the discriminant validity of the PUTS. Factor analysis for construct validity revealed three factors: "presumed functional relationship between the tic and the urge to tic," "the quality of the premonitory urge," and "just right phenomena."

Conclusion

The results of this study indicate that the K-PUTS is a reliable and valid scale for rating premonitory urge of tics.

The role of prebiotics in cognition, anxiety, and depression

The disruption of the gut microbial composition, defined as dysbiosis, has been associated with many neurological disorders with inflammatory components. The alteration of the gut microbiota leads to an increase in pro-inflammatory cytokines that are associated with metabolic diseases (such as obesity and type 2 diabetes), autoimmune arthritis, and neuropsychiatric diseases. Prebiotics are defined as non-digestible carbohydrates and promote the growth of beneficial bacteria such as bifidobacteria and lactobacillus, exert beneficial effects on improving dysbiosis and its associated inflammatory state. Preclinical and clinical data indicated that some prebiotics also have positive impacts on the central nervous system (CNS) due to the modulation of neuroinflammation and thus may have a key role in the modulation of cognitive impairment, anxiety, and depression. The present manuscript reviews the state-of-art of the effects of prebiotics in cognitive impairment, anxiety, and depressive disorders. Data from clinical studies are still scarce, and further clinical trials are needed to corroborate the potential therapeutic cognitive, antidepressant, and anxiolytic of prebiotics. Prebiotics may provide patients suffering from cognitive deficits, depression, and anxiety with a new tool to minimize disease symptoms and increase the quality of life.

Dysregulation of synaptic pruning as a possible link between intestinal microbiota dysbiosis and neuropsychiatric disorders

The prenatal and early postnatal stages represent a critical time window for human brain development. Interestingly, this window partly overlaps with the maturation of the intestinal flora (microbiota) that play a critical role in the bidirectional communication between the central and the enteric nervous systems (microbiota-gut-brain axis). The microbial composition has important influences on general health and the development of several organ systems, such as the gastrointestinal tract, the immune system, and also the brain. Clinical studies have shown that microbiota alterations are associated with a wide range of neuropsychiatric disorders including autism spectrum disorder, attention deficit hyperactivity disorder, schizophrenia, and bipolar disorder. In this review, we dissect the link between these neuropsychiatric disorders and the intestinal microbiota by focusing on their effect on synaptic pruning, a vital process in the maturation and establishing efficient functioning of the brain. We discuss in detail how synaptic pruning is dysregulated differently in the aforementioned neuropsychiatric disorders and how it can be influenced by dysbiosis and/or changes in the intestinal microbiota composition. We also review that the improvement in the intestinal microbiota composition by a change in diet, probiotics, prebiotics, or fecal microbiota transplantation may play a role in improving neuropsychiatric functioning, which can be at least partly explained via the optimization of synaptic pruning and neuronal connections. Altogether, the demonstration of the microbiota's influence on brain function via microglial-induced synaptic pruning addresses the possibility that the manipulation of microbiota-immune crosstalk represents a promising strategy for treating neuropsychiatric disorders.