Alleviation of Anxiety/Depressive-Like Behaviors and Improvement of Cognitive Functions by Lactobacillus plantarum WLPL04 in Chronically Stressed Mice

Effects of a Lacticaseibacillus Mix on Behavioural, Biochemical, and Gut Microbial Outcomes of Male Mice following Chronic Restraint Stress

The effect of supplementation with Lactobacillus strains to prevent the consequences of chronic stress on anxiety in mouse strains sensitive to stress and the consequences on gut microbiota have been relatively unexplored. Thus, we administered a Lacticaseibacillus casei LA205 and Lacticaseibacillus paracasei LA903 mix to male BALB/cByJrj mice two weeks before and during 21-day chronic restraint stress (CRS) (non-stressed/solvent (NS-PBS), non-stressed/probiotics (NS-Probio), CRS/solvent (S-PBS), CRS/probiotics (S-Probio)). CRS resulted in lower body weight and coat state alteration, which were attenuated by the probiotic mix. S-Probio mice showed less stress-associated anxiety-like behaviours than their NS counterpart, while no difference was seen in PBS mice. Serum corticosterone levels were significantly higher in the S-Probio group than in other groups. In the hippocampus, mRNA expression of dopamine and serotonin transporters was lower in S-Probio than in S-PBS mice. Few differences in bacterial genera proportions were detected, with a lower relative abundance of Alistipes in S-Probio vs. S-PBS. CRS was accompanied by a decrease in the proportion of caecal acetate in S-PBS mice vs. NS-PBS, but not in the intervention groups. These data show that the probiotic mix could contribute to better coping with chronic stress, although the precise bacterial mechanism is still under investigation.

The Intertwining Roads between Psychological Distress and Gut Microbiota in Inflammatory Bowel Disease

Inflammatory bowel disease represents one of the most life-altering gastrointestinal pathologies, with its multifactorial nature and unclear physiopathology. The most relevant clinical forms, ulcerative colitis and Crohn's disease, clinically manifest with mild to severe flares and remission periods that alter the patient's social, familial and professional integration. The chronic inflammatory activity of the intestinal wall determines severe modifications of the local environment, such as dysbiosis, enteric endocrine, nervous and immune system disruptions and intestinal wall permeability changes. These features are part of the gastrointestinal ecosystem that modulates the bottom-to-top signaling to the central nervous system, leading to a neurobiologic imbalance and clinical affective and/or behavioral symptoms. The gut-brain link is a bidirectional pathway and psychological distress can also affect the central nervous system, which will alter the top-to-bottom regulation, leading to possible functional digestive symptoms and local inflammatory responses. In the middle of this neuro-gastrointestinal system, the microbiome is a key player, as its activities offer basic functional support for both relays. The present article presents current scientific information that links the pathophysiology and clinical aspects of inflammatory bowel disease and psychiatric symptomatology through the complex mechanism of the gut-brain axis and the modulatory effects of the gut microbiota.

Study on Lactiplantibacillus plantarum R6-3 from Sayram Ketteki to prevent chronic unpredictable mild stress-induced depression in mice through the microbiota-gut-brain axis

The prevention, mitigation and treatment of depression has become a global issue that needs to be solved urgently. Sayram Ketteki, a traditional natural fermented yoghurt from the region with the world's fourth highest life expectancy, has been known as the "longevity secret", whose longevity and anti-depression factors are speculated to come from its rich microorganisms. Therefore, for the first time, we systematically studied in depth the microbes of Sayram Ketteki, screened a new edible probiotic strain, Lactiplantibacillus plantarum R6-3, and explored its anti-depression effect in chronic unpredictable mild stress (CUMS)-induced depression in mice. It is encouraging that L. plantarum R6-3 was significantly superior to the classic anti-depressant drug, fluoxetine, in the performance of promoting sucrose preference test (SPT) behavior by 18% (p < 0.001), lowering the serum CORT content by 5.6% (p < 0.05), accelerating the brain-derived neurotrophic factor (BDNF) level by 5.9% (p < 0.01), increasing the serum IL-10 concentration by 2.3% (p < 0.05), up-regulating the expression of BDNF and phosphorylated-ERK by 74% (p < 0.01) and 45% (p < 0.001), respectively, and facilitating the secretion of fecal short-chain fatty acids (SCFAs), including n-butyric, n-valeric, and isovaleric acid by 47% (p < 0.01), 42% (p < 0.05) and 38% (p < 0.05), respectively. Through the microbiota-gut-brain axis, L. plantarum R6-3 promoted the secretion of intestinal SCFAs through regulation of the composition and function of the gut microbiota, and activated the production of the monoamine neurotransmitter, renewed the level of brain neurotrophic factor, and suppressed the hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis by adjusting the hippocampal BDNF/TrkB/ERK/CREB signaling pathway, thereby improving the immune and oxidative stress status, protecting hippocampal tissue from damage, maintaining a healthy weight and preventing CUMS-induced depressive behavior in mice. It has great prospects for the development of natural functional foods, the prevention and treatment of depression and in innovative microecological preparations.

Overcoming Anxiety Disorder by Probiotic Lactiplantibacillus plantarum LZU-J-TSL6 through Regulating Intestinal Homeostasis

Lactiplantibacillus plantarum LZU-J-TSL6 with high γ-aminobutyric acid (GABA) production (3.838 g/L) was screened and isolated from the Chinese fermented food snack “Jiangshui”. The improvement effect on anxiety disorder was explored using mice as animal models. In vitro results revealed that LZU-J-TSL6 had the potential to colonize the intestine (p < 0.01) and the anxiety-like behavior of the mice after seven days’ gavage with LZU-J-TSL6 was significantly improved (p < 0.01) when compared to the model group. LZU-J-TSL6 was able to effectively increase the GABA content in the mice hippocampus (p < 0.0001) and restore some markers related to anxiety such as brain-derived neurotrophic factor (BDNF), glial fibrillary acidic protein (GFAP), and 5-hydroxytryptamine (5-HT). Simultaneously, it had a certain repair effect on Nissl bodies and colon tissue in mice hippocampus. In addition, LZU-J-TSL6 increased the relative abundance of beneficial bacteria Bacteroides and Muribaculum, thereby regulating the imbalance of intestinal microbiota caused by anxiety disorder. It also affects the nerve pathway and intestinal mucosal barrier by increasing the content of glutamine and γ-aminobutyric acid and other related metabolites, thereby improving anxiety. Therefore, the GABA-producing Lactobacillus plantus LZU-J-TSL6 can be used as a probiotic to exert an indirect or direct anti-anxiety effect by maintaining the balance of the intestinal environment, producing related metabolites that affect nerve pathways and repair the intestinal mucosal barrier. It can be used as an adjuvant treatment to improve anxiety disorders.

Clinical Application Value of Lactobacillus Plantarum PS128 in Patients with Anxiety Disorders

Objective

PS128 is a novel psycho biotic strain, it has been reported to play an important role in neuropsychiatric disorders. This study investigated the clinical effect of PS128 supplementation on patients with anxiety.

Methods

A total of 200 patients with anxiety were recruited, and divided into two groups (n = 100/group). The control group received oral treatment with citalopram, and the PS128 group received PS128 capsules based on citalopram treatment. Hamilton Anxiety Scale (HAMA) and Self-Rating Anxiety Scale (SAS) were used to evaluate the anxiety levels. After 2 months of continuous administration, clinical efficacy was evaluated according to HAMA score.

Results

There was no significant difference in HAMA and SAS scores between the two groups before treatment. With the treatment prolonged, the HAMA and SAS score decreased gradually in both control and PS128 groups, and the decrease rate of PS128 group was significantly greater than that of the control group. The clinical effective rates of PS128 group were higher than those in the control group, high levels of clinical cure rate were also detected in the PS128 group. Compared with the control group (22%), the incidence of adverse reactions was significantly reduced for patients in the PS128 group (4%).

Conclusion

The treatment effect of citalopram combined with PS128 against anxiety is satisfactory clinically. It can greatly improve the anxiety symptoms of patients, increase the cure rate, reduce adverse reactions.

Lactobacillus plantarum-derived postbiotics prevent Salmonella-induced neurological dysfunctions by modulating gut-brain axis in mice

Postbiotics are the inactive bacteria and/or metabolites of beneficial microbes which have been recently found to be as effective as their live probiotic. This study aimed to evaluate the benefits of Lactobacillus plantarum (LP)-derived postbiotics on ameliorating Salmonella-induced neurological dysfunctions. Mice were pretreated with LP postbiotics (heat-killed bacteria or the metabolites) or active bacteria, and then challenged with Salmonella enterica Typhimurium (ST). Results showed that LP postbiotics, particularly the metabolites, effectively prevented ST infection in mice, as evidenced by the inhibited weight loss, bacterial translocation, and tissue damages. The LP postbiotics markedly suppressed brain injuries and neuroinflammation (the decreased interleukin (IL)-1β and IL-6, and the increased IL-4 and IL-10). Behavior tests indicated that LP postbiotics, especially the metabolites, protected mice from ST-induced anxiety and depressive-like behaviors and cognitive impairment. A significant modulation of neuroactive molecules (5-hydroxytryptamine, gamma-aminobutyric acid, brain-derived neurotrophic factor, dopamine, acetylcholine, and neuropeptide Y) was also found by LP postbiotic pretreatment. Microbiome analysis revealed that LP postbiotics optimized the cecal microbial composition by increasing Helicobacter, Lactobacillus and Dubosiella, and decreasing Mucispirillum, norank_f_Oscillospiraceae, and Eubacterium_siraeum_group. Moreover, LP postbiotics inhibited the reduction of short-chain fatty acids caused by ST infection. Pearson's correlation assays further confirmed the strong relationship of LP postbiotics-mediated benefits and gut microbiota. This study highlights the effectiveness of postbiotics and provide a promising strategy for preventing infection-induced brain disorders by targeting gut–brain axis.

Probiotic potential of GABA-producing lactobacilli isolated from Uruguayan artisanal cheese starter cultures

AIMS

In this study, we sought to identify and characterize a collection of 101 lactobacilli strains isolated from natural whey starters used in Uruguayan artisan cheese production, based on their capacity to produce gamma-aminobutyric acid (GABA) and their probiotic potential.

METHODS AND RESULTS

The probiotic potential was assessed using low pH and bile salt resistance assays; bacterial adhesion to intestinal mucus was also evaluated. Selected strains were then identified by 16S sequencing, and their GABA-producing potential was confirmed and quantified using a UHPLC-MS system. Twenty-five strains were identified and characterized as GABA-producing lactobacilli belonging to the phylogenetical groups Lactiplantibacillus (n = 19) and Lacticaseibacillus (n = 6). Fifteen strains of the Lactiplantibacillus group showed a significantly higher GABA production than the rest. They showed the predicted ability to survive the passage through the gastrointestinal tract, according to the in vitro assays.

CONCLUSIONS

A set of promising candidate strains was identified as potential probiotics with action on the gut-brain axis. Further studies are needed to assess their possible effects on behaviour using in vivo assay.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study shows the potential of strains isolated from local natural whey starters as probiotics and for biotechnological use in functional GABA-enriched foods formulation.

The Microbiota-Gut-Brain Axis in Depression: The Potential Pathophysiological Mechanisms and Microbiota Combined Antidepression Effect

Depression is a kind of worldwide mental illness with the highest morbidity and disability rate, which is often accompanied by gastrointestinal symptoms. Experiments have demonstrated that the disorder of the intestinal microbial system structure plays a crucial role in depression. The gut–brain axis manifests a potential linkage between the digestion system and the central nervous system (CNS). Nowadays, it has become an emerging trend to treat diseases by targeting intestinal microorganisms (e.g., probiotics) and combining the gut–brain axis mechanism. Combined with the research, we found that the incidence of depression is closely linked to the gut microbiota. Moreover, the transformation of the gut microbiota system structure is considered to have both positive and negative regulatory effects on the development of depression. This article reviewed the mechanism of bidirectional interaction in the gut–brain axis and existing symptom-relieving measures and antidepression treatments related to the gut microbiome.

The Effects of Stress and Diet on the "Brain-Gut" and "Gut-Brain" Pathways in Animal Models of Stress and Depression

Compelling evidence is building for the involvement of the complex, bidirectional communication axis between the gastrointestinal tract and the brain in neuropsychiatric disorders such as depression. With depression projected to be the number one health concern by 2030 and its pathophysiology yet to be fully elucidated, a comprehensive understanding of the interactions between environmental factors, such as stress and diet, with the neurobiology of depression is needed. In this review, the latest research on the effects of stress on the bidirectional connections between the brain and the gut across the most widely used animal models of stress and depression is summarised, followed by comparisons of the diversity and composition of the gut microbiota across animal models of stress and depression with possible implications for the gut–brain axis and the impact of dietary changes on these. The composition of the gut microbiota was consistently altered across the animal models investigated, although differences between each of the studies and models existed. Chronic stressors appeared to have negative effects on both brain and gut health, while supplementation with prebiotics and/or probiotics show promise in alleviating depression pathophysiology.

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.

Probiotics as a Treatment for "Metabolic Depression"? A Rationale for Future Studies

Depression and metabolic diseases often coexist, having several features in common, e.g., chronic low-grade inflammation and intestinal dysbiosis. Different microbiota interventions have been proposed to be used as a treatment for these disorders. In the paper, we review the efficacy of probiotics in depressive disorders, obesity, metabolic syndrome and its liver equivalent based on the published experimental studies, clinical trials and meta-analyses. Probiotics seem to be effective in reducing depressive symptoms when administered in addition to antidepressants. Additionally, probiotics intake may ameliorate some of the clinical components of metabolic diseases. However, standardized methodology regarding probiotics use in clinical trials has not been established yet. In this narrative review, we discuss current knowledge on the recently used methodology with its strengths and limitations and propose criteria that may be implemented to create a new study of the effectiveness of probiotics in depressive disorders comorbid with metabolic abnormalities. We put across our choice on type of study population, probiotics genus, strains, dosages and formulations, intervention period, as well as primary and secondary outcome measures.

Probiotic Escherichia coli Ameliorates Antibiotic-Associated Anxiety Responses in Mice

Despite the beneficial actions of antibiotics against bacterial infections, the use of antibiotics is a crucial etiological factor influencing microbial dysbiosis-associated adverse outcomes in human health. Based on the assumption that gut microbial dysbiosis can provoke behavioral or psychological disorders, the present study evaluated anxiety-linked behavioral changes in a mouse model of streptomycin-induced dysbiosis. Measuring anxiety-like behavior using the light-dark box and elevated plus maze tests indicated that streptomycin treatment caused acute anxiety in mice. As an intervention for dysbiosis-associated distress, the probiotic strain Escherichia coli Nissle 1917 (EcN) was evaluated for its effects on streptomycin-induced behavioral changes in mice. EcN supplementation persistently ameliorated anxiety responses in mice with streptomycin-induced dysbiosis. As an outcome of anxiety, body weight changes were marginally affected by antibiotic treatment. However, mice supplemented with EcN displayed acute retardation of body weight gain, since EcN is known to reduce food intake and increase energy expenditure. Taken together, EcN treatment prominently counteracted streptomycin-induced anxiety in mice, with the metabolically beneficial retardation of body weight gain. The present model simulates psychological disorders in antibiotic users. As a promising intervention, EcN treatment can facilitate psychological relief under conditions of dysbiotic stress by blocking the pathologic gut-brain circuit.