Probiotics as a Tool for Regulating Molecular Mechanisms in Depression: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Folate from probiotic bacteria and its therapeutic applications

Folate, an essential water soluble vitamin B9 that cannot be synthesized naturally by the bodily function. Dietary sources or probiotic-folates are the two biological modes for acquiring the target vitamin which aids DNA synthesis and repair. Probiotics are known for their divergent health benefits and have garnered significant interest. Particularly in microbial strains that produce folate offers a promising way to enhance the level of folate. Notably, folate-producing probiotic strain includes Lactiplantibacillus, Lactococcus, Bifidobacterium, and Streptococcus. As an emerging source of health benefits, folate producing probiotics helps in improving the gut microbiota for overall well-being of human body. On the other side, chemically synthesized folic acid were not highly advantageous as they lacks absorption, conversion and excretion. Hence, usage of microbial-folate are safer as it can easily undergo absorption and reduces severe side effects. The present review mainly focus on folate one-carbon metabolism, its significance in human health, folate deficiency and malabsorption, adverse effects and folate synthesis from probiotic bacterial strains, and also toxicological impacts. In particular, the beneficiary role of these probiotic strains were found to be associated with therapeutic applications in several diseases such as autoimmune disorder, metabolic disorders, and cardiovascular diseases (CVDs), wound healing, drug delivery and cancer.

Role of gut microbiota in thalassemia: a review of therapeutic prospects

In recent years, the study of gut microbiota has gradually become a research hotspot in the field of medicine, as gut microbiota dysbiosis is closely related to various diseases. Thalassemia, as a hereditary hemoglobinopathy, has a complex pathophysiological mechanism, and traditional treatment methods show limited efficacy. With a deeper understanding of the gut microbiome, researchers have begun to focus on its role in the pathogenesis of thalassemia and its therapeutic effects. This article aims to review the role of gut microbiota in thalassemia and its potential therapeutic prospects, analyze the latest research findings, and explore the impact and mechanisms of gut microbiota on patients with thalassemia, with the goal of providing new ideas and directions for future research and clinical treatment of thalassemia.

Immune dysregulation in psychiatric disorders with and without exposure to childhood maltreatment: A transdiagnostic stratified meta-analysis

INTRODUCTION

Childhood maltreatment (CM), i.e. physical, psychological, or sexual abuse and neglect, affects approximately one third of the general population and is an important risk factor for all major psychiatric disorders. Exposure to CM also has a profound impact on immune function, with both factors independently implicated in the development and prognosis of different mental disorders. This study aims to 1) assess differences in immune markers among adults diagnosed with psychiatric disorders with and without a history of CM and 2) explore the role of CM as a mediating factor in immune abnormalities among psychiatric patients compared to non-psychiatric controls.

METHODS

A PRISMA-compliant systematic search of PubMed, Web of Science and Embase databases was performed until October 24th, 2024 for original studies that assessed immune markers in trauma-stratified adult psychiatric patients (PROSPERO ID CRD42021273059). We modelled random-effects meta-analyses to compare levels of pro-inflammatory (PIM), anti-inflammatory (AIM) and cellular immune markers (CIM) between traumatized (CM + ) and non-traumatized (CM-) individuals, and investigated exposure to CM as a mediating factor in the immune abnormalities among adult psychiatric patients compared to non-psychiatric controls. Secondary analyses were performed for diagnostic subgroups and individual immune markers. Study quality was assessed with the Newcastle Ottawa Scale.

RESULTS

We included data from 53 studies on n = 12,141 patients with mood disorders (MD), schizophrenia spectrum disorders (SSD), substance use disorders (SUD), eating disorders (ED) and anxiety disorders (AD). We uncovered a consistent transdiagnostic impact of CM on blood-based pro-inflammatory molecules (OR = 1.186; 95 % CI 1.030-1.365, p = 0.018) among patients with psychiatric disorders. This effect was not observed in the non-psychiatric controls included in the same studies. We did not find evidence of specific trauma-induced abnormalities in immune composite scores for separate diagnostic subgroups, except for PIM in SUD patients (OR = 2.324, 95 % CI 1.043-5.182, p = 0.039). Interleukin 6 (IL-6) was identified as a significant mediator between CM exposure and a psychiatric diagnosis in adulthood (OR = 1.609; 95 % CI 1.100-2.353, p = 0.014), while increases in C-reactive protein (CRP) and Interleukin 10 (IL-10) did not appear to be trauma-specific.

CONCLUSION

Our findings confirm a transdiagnostic impact of exposure to CM on increased pro-inflammatory molecular and cellular immune levels in psychiatric patients. IL-6 emerged as a crucial mediator, suggesting that CM leads to specific immune alterations predisposing individuals to psychiatric conditions. This meta-analysis highlights the role of trauma-induced immune abnormalities as a potentially crucial mechanism contributing to increased vulnerability towards mental illness later in life.

Efficacy and safety of gut microbiome-targeted treatment in patients with depression: a systematic review and meta-analysis

BACKGROUND

The study aimed to comprehensively analyze and establish a framework for evaluating the efficacy of microbiome-targeted treatment (MTT) for depression.

METHODS

We searched PubMed, Embase, Cochrane Library, Web of Science, and the Chinese National Knowledge Infrastructure database for randomized controlled trials (RCTs) on MTT in treating depression until October 19, 2023. A meta-analysis was conducted to evaluate the efficacy and safety of MTT. Comprehensive subgroup analyses were undertaken to explore factors influencing MTT's efficacy in treating depression. This study was registered with PROSPERO (CRD42023483649).

RESULTS

The study selection process identified 51,570 studies, of which 34 met the inclusion criteria. The overall pooled estimates showed that MTT significantly improved depression symptoms (SMD -0.26, 95% CI [-0.32, -0.19], I2 = 54%) with acceptable safety. Subgroup analyses by geography showed that effectiveness was demonstrated in Asia (SMD -0.46, 95% CI [-0.56, -0.36], I2 = 36%), while no evidence of effectiveness was found in Europe (SMD -0.07, 95% CI [-0.19, 0.05], I2 = 55%), America (SMD -0.33, 95% CI [-0.67, 0.02], I2 = 60%), and Oceania (SMD 0.00, 95% CI [-0.18, 0.18], I2 = 0%). Besides, the efficacy was shown in depressed patients without comorbidities (SMD -0.31, 95% CI [-0.40, -0.22], I2 = 0%), whereas effectiveness was poor in those with digestive disorders, such as irritable bowel syndrome (SMD -0.37, 95% CI [-0.89, 0.16], I2 = 74%), chronic diarrhea (SMD -0.34, 95% CI [-0.73, 0.05]), and chronic constipation (SMD -0.23, 95% CI [-0.57, 0.11], I2 = 0%). In perinatal depressed patients, MTT was not effective (SMD 0.16, 95% CI [0.01, 0.31], I2 = 0%). It was found that < 8 weeks (SMD -0.33, 95% CI [-0.45, -0.22], I2 = 0%) and 8-12 weeks (SMD -0.34, 95% CI [-0.44, -0.23], I2 = 57%) MTT were effective, while > 12 weeks (SMD 0.02, 95% CI [-0.12, 0.17], I2 = 68%) MTT was ineffective.

CONCLUSIONS

Despite the overall effectiveness of MTT in treating depression and its acceptable safety profile, caution is warranted in drawing this conclusion due to limitations posed by the small sample size of included studies and heterogeneity. The efficacy of MTT for depression exhibits variation influenced by geography, patient comorbidities, and duration of administration.

Effect of Probiotics Supplementation on Cortisol Levels: A Systematic Review and Meta-Analysis

Background: Several randomized controlled trials (RCTs) have shown conflicting results on cortisol levels following probiotic administration in healthy and diseased populations. Previous analyses were inconclusive due to limited studies, and evidence is lacking on how these effects vary by health status; region; therapy duration; medications, and use of single or multiple strains. Methods: In this systematic review and meta-analysis (PROSPERO [CRD42024538539]), we searched PubMed, Cochrane Library, Embase, Scopus, Web of Science, CINAHL, ProQuest, and Web of Science Preprints until 13 August 2024, for RCTs on probiotic administration, either alone or combined, across all age groups and without specific medical condition requirements. We applied random-effects meta-analysis, assessed bias using the Cochrane RoB 2 tool, and evaluated evidence certainty with GRADE. Findings: We screened 1739 records and retrieved 46 RCTs (3516 participants). Probiotics supplementation decreased cortisol levels compared to the control arm [46 RCTs; SMD: -0.45; 95% CI: -0.83; -0.07; I2: 92.5%, low certainty]. Among various subgroups; probiotics supplementation decreased the cortisol levels in the subgroups without concomitant medications [37 RCTs; SMD: -0.30; 95% CI [-0.58; -0.03], I2: 88.7%] with a single probiotic strain [30 RCTs; SMD: -0.33; 95% CI: -0.63; -0.028; I2: 88.8%], in a healthy population [35 RCTs; SMD:-0.3; 95% CI: -0.58; -0.03; I2: 88.7] and in the Asia region [21 RCTs; SMD: -0.83; 95% CI: -1.58; -0.07; I2: 95%]. Interpretation: A low level of evidence suggests probiotics might reduce cortisol levels, but more targeted studies are needed to identify variables affecting the response in specific subgroups.

The Effectiveness and Safety Analysis of Duloxetine in Treating Comorbid Depression in Parkinson's Disease: A Retrospective Study

BACKGROUND

Parkinson's disease (PD) is a neurodegenerative disorder characterized by both motor and non-motor symptoms, including depression, which significantly impacts the quality of life of affected individuals. This study aims to investigate the real-world effectiveness and safety of duloxetine in treating comorbid depression in patients with Parkinson's disease and to compare its outcomes with traditional treatment approaches.

METHODS

This study included adult patients diagnosed with Parkinson's disease combined with depression from December 2020 to December 2023. Based on the use of duloxetine, the cohort was divided into a traditional treatment group and a duloxetine group (traditional treatment combined with duloxetine). Patients with incomplete medical records, concurrent antidepressant therapy, or major psychiatric or neurological disorders were excluded. Retrospective data, including demographic information, treatment adherence, and various assessment scores, were collected from medical records by trained research staff.

RESULTS

In total, 106 patients were analyzed, with 50 patients receiving traditional treatment and 56 patients receiving duloxetine. The duloxetine group exhibited significantly lower scores than the traditional treatment group in the Unified PD Rating Scale (p = 0.015), Hamilton Depression Rating Scale (p = 0.013), Beck Depression Inventory (p = 0.031), Parkinson's disease Questionnaire-39 (p = 0.006), and Clinical Global Impression-Improvement (p < 0.001) scores. In motor function assessment, the duloxetine group demonstrated improvements in kinetic tremor scores (p = 0.017), gait speed (p < 0.001), Timed Up and Go Test performance (p < 0.001), dyskinesia severity (p = 0.017), and rigidity (p = 0.019) compared to the traditional treatment group. Additionally, the duloxetine group exhibited better cognitive function across various assessments, including the Symbol Digit Modalities Test (p = 0.024), Stroop Color-Word Test (p = 0.048), and Montreal Cognitive Assessment (p = 0.024).

CONCLUSION

Duloxetine is associated with superior efficacy in improving motor and non-motor symptoms, overall clinical status, and cognitive function. These findings support the potential utility of duloxetine as a comprehensive treatment option for comorbid depression in Parkinson's disease.

What We Know About the Actual Role of Traditional Probiotics in Health and Disease

The complex relationship between probiotics and human health goes beyond their traditional function in gut health, generating considerable interest for their broad potential in disease treatment. This review explores the various functions of probiotics, highlighting their impact on the immune system, their benefits for gut and oral health, their effects on metabolic and neurological disorders, and their emerging potential in cancer therapy. We give significant importance to studying the effects of probiotics on the gut-brain axis, revealing new and non-invasive therapeutic approaches for complex neurological disorders. In addition, we expand the discussion to encompass the impact of probiotics on the gut-liver and gut-lung axes, recognizing their systemic effects and potential in treating respiratory and hepatic conditions. The use of probiotic "cocktails" to improve cancer immunotherapy outcomes indicates a revolutionary approach to oncological treatments. The review explores the specific benefits associated with various strains and the genetic mechanisms that underlie them. This study sets the stage for precision medicine, where probiotic treatments can be tailored to meet the unique needs of each patient. Recent developments in delivery technologies, including microencapsulation and nanotechnology, hold great potential for enhancing the effectiveness and accuracy of probiotic applications in therapeutic settings. This study provides a strong basis for future scientific research and clinical use, promoting the incorporation of probiotics into treatment plans for a wide range of diseases. This expands our understanding of the potential benefits of probiotics in modern medicine.

Pediococcus pentosaceus PP34 Ameliorates 5-Fluorouracil-Induced Intestinal Mucositis via Inhibiting Oxidative Stress and Restoring the Gut Microbiota

Chemotherapy-induced intestinal mucositis based on 5-fluorouracil (5-FU) slows down the progress of cancer treatment and causes significant suffering to patients. Pediococcus pentosaceus (P. pentosaceus), as a type of LAB, has a range of probiotic properties, including antioxidant, immune benefits, and cholesterol-lowering effects, which are attracting increasing attention. However, studies on the protective effect of P. pentosaceus against chemotherapeutic-induced intestinal mucositis caused by 5-FU remain unclear. Therefore, this study aimed to investigate the potential relieving effects of P. pentosaceus PP34 on 5-FU-induced intestinal mucositis and its mechanism. In the present study, a P. pentosaceus PP34 solution (2 × 109 CFU/mL) was administered daily by gavage followed by intraperitoneal injection of 5-FU to model intestinal mucositis. The body weight, serum biochemical indices, jejunal pathological organization, and expression levels of inflammatory cytokines in the jejunum were examined. The results indicated that the mice induced with 5-FU developed typical intestinal mucositis symptoms and histopathological changes with intense inflammatory and oxidative responses. Moreover, the gut microbiota was disturbed, while PP34 effectively decreased the oxidative reactions and the expression levels of inflammatory mediators and regulated the gut microbiota in 5-FU-exposed mice. Taken together, the study indicated that P. pentosaceus PP34 ameliorates 5-Fluorouracil-induced intestinal mucositis via inhibiting oxidative stress and restoring the gut microbiota.

Effects of exercise therapy on anxiety and depression in patients with COVID-19: a systematic review and meta-analysis

Objective

With increasing rates of anxiety and depression during COVID-19, exercise treatment has drawn attention for its effects on COVID-19 patients with anxiety and depression. This study set out to assess the impact of exercise therapy on COVID-19 patients' anxiety and depression.

Methods

PubMed, EMBASE, Web of Science and Cochrane Library were used to search articles about exercise therapy as a means of treating anxiety and depression in COVID-19 patients from inception to April 30, 2023. The risk of bias was assessed by the Cochrane Collaboration bias risk tool. Data were pooled with the random effects model. RevMan version 5.4 was used for the statistical analyses. This work was registered in the PROSPERO database (registration number: CRD42023406439).

Selection criteria

Randomized clinical trials (RCTs) of COVID-19 patients with anxiety and depression were included to assess the impact of physical exercise on COVID-19 patients with anxiety and depression.

Results

6 studies including a total of 461 COVID-19 patients were analyzed in this meta-analysis. Overall, the meta-analysis showed that compared with the control group, exercise could significantly improve anxiety (SMD = -0.76; 95%CI: -0.96, -0.55; p < 0.00001), depression level (SMD = -0.39; 95%CI: -0.70, -0.09; p = 0.01), the PHQ-9 score (MD = -1.82; 95%CI: -2.93, -0.71; p = 0.001) and the sleep quality (SMD = -0.73; 95%CI: -1.32, -0.14; p = 0.01) in COVID-19 patients.

Conclusion

The research provided evidence that exercise therapy is able to help COVID-19 patients experience less anxiety and depression and have better-quality sleep.

Systematic review registration

CRD42023406439.

Probiotics and Prebiotics Affecting Mental and Gut Health

The effects of the gut microbiota on mental and intestinal health are an area of great interest. This study aimed to reveal the relationship between the intake of probiotic and prebiotic foods and mental and gut health. Data were obtained using an online survey from young adults (n = 538) enrolled at Afyonkarahisar Health Sciences University who agreed to participate in this study in the 2022-2023 academic year. This study included 538 participants, mostly (85.5%) females. Participants who never consumed yogurt had 7.614 times higher Gastrointestinal Symptom Rating Scale scores than those who consumed yogurt daily (p < 0.01). Similarly, the frequency of ayran consumption had a statistically significant effect on Bristol Stool Scale scores (p < 0.05). The ratio of normal defecation to constipation was 68.7% lower in participants who consumed ayran daily, whereas the ratio of diarrhea to constipation was 76.4% lower in participants who never consumed ayran. However, the frequency of prebiotic consumption did not have a significant effect on Bristol Stool Scale scores (p > 0.05). The consumption of probiotic and prebiotic foods exerted a significant effect on GSRS total scores and subfactors of the Depression Anxiety Stress Scale-42, namely depression, anxiety, and stress.

Probiotics' Effects in the Treatment of Anxiety and Depression: A Comprehensive Review of 2014-2023 Clinical Trials

Changes in the gut microbiome can affect cognitive and psychological functions via the microbiota-gut-brain (MGB) axis. Probiotic supplements are thought to have largely positive effects on mental health when taken in sufficient amounts; however, despite extensive research having been conducted, there is a lack of consistent findings on the effects of probiotics on anxiety and depression and the associated microbiome alterations. The aim of our study is to systematically review the most recent literature of the last 10 years in order to clarify whether probiotics could actually improve depression and anxiety symptoms. Our results indicate that the majority of the most recent literature suggests a beneficial role of probiotics in the treatment of depression and anxiety, despite the existence of a substantial number of less positive findings. Given probiotics' potential to offer novel, personalized treatment options for mood disorders, further, better targeted research in psychiatric populations is needed to address concerns about the exact mechanisms of probiotics, dosing, timing of treatment, and possible differences in outcomes depending on the severity of anxiety and depression.

The Role of Bifidobacterium bifidum novaBBF7, Bifidobacterium longum novaBLG2 and Lactobacillus paracasei TJB8 to Improve Mechanisms Linked to Neuronal Cells Protection against Oxidative Condition in a Gut-Brain Axis Model

Despite the identification of several innovative targets for avoiding cognitive decline, there has yet to be a widely accepted approach that deals with minimising the deterioration of cognitive function. In this light, recent studies suggest that regulating the gut-brain axis with probiotics is a potential therapeutic strategy to support brain health. For this reason, in vitro models were used to examine the efficacy of different probiotic combinations to enhance intestinal homeostasis and positively affect the brain. Therefore, the new formulation has been evaluated for its capacity to modify intestinal barrier functions in a 3D in vitro model without any adverse effects and directly impact the mechanisms underlying cognitive function in a gut-brain axis model. According to our findings, B. bifidum novaBBF7 10 mg/mL, B. longum novaBLG2 5 mg/mL and L. paracasei TJB8 10 mg/mL may successfully modify the intestinal barrier and improve SCFA production. Successively, the probiotics studied caused no harm at the neuronal level, as demonstrated by iNOS, mitochondrial potential, and cell viability tests, confirming their safety features and enhancing antioxidant mechanisms and antineuroinflammation activity. Additionally, the damage caused by oxidative stress was also healed, and critical pathways that result in cognitive impairment were changed by synergetic action, supporting the hypothesis that brain ageing and neurodegeneration are slowed down. All these findings demonstrate the ability of probiotics to affect cognitive processes and their ability to sustain the mechanisms underlying cognitive function by acting on intestinal function.

The Role of Probiotics and Their Metabolites in the Treatment of Depression

Depression is a common and complex mental and emotional disorder that causes disability, morbidity, and quite often mortality around the world. Depression is closely related to several physical and metabolic conditions causing metabolic depression. Studies have indicated that there is a relationship between the intestinal microbiota and the brain, known as the gut–brain axis. While this microbiota–gut–brain connection is disturbed, dysfunctions of the brain, immune system, endocrine system, and gastrointestinal tract occur. Numerous studies show that intestinal dysbiosis characterized by abnormal microbiota and dysfunction of the microbiota–gut–brain axis could be a direct cause of mental and emotional disorders. Traditional treatment of depression includes psychotherapy and pharmacotherapy, and it mainly targets the brain. However, restoration of the intestinal microbiota and functions of the gut–brain axis via using probiotics, their metabolites, prebiotics, and healthy diet may alleviate depressive symptoms. Administration of probiotics labeled as psychobiotics and their metabolites as metabiotics, especially as an adjuvant to antidepressants, improves mental disorders. It is a new approach to the prevention, management, and treatment of mental and emotional illnesses, particularly major depressive disorder and metabolic depression. For the effectiveness of antidepressant therapy, psychobiotics should be administered at a dose higher than 1 billion CFU/day for at least 8 weeks.