Mind, Mood and Microbiota-Gut-Brain Axis in Psychiatric Disorders

Potential clinical benefits of probiotics, prebiotics, synbiotics, and postbiotics for depression via the microbiota-gut-brain axis

BACKGROUND

Depression is a common mental-health disorder worldwide. Several studies have demonstrated the effects of gut microbiota-targeting interventions, such as probiotics, prebiotics, synbiotics, and postbiotics (PPSP), on depression.

AIM

To assess the potential benefits of PPSP on patients diagnosed with depressive disorder.

METHODS

A literature search of the PubMed, Web of Science, and Elsevier Science Direct databases for relevant studies published from database inception to March 2024 was performed. Studies that used a randomized controlled trial design and evaluated differences in depression between PPSP and placebo were included. Depressive symptoms were assessed using a validated scale. Analysis was performed using Review Manager version 5.4 (The Cochrane Collaboration, 2020).

RESULTS

Fourteen studies comprising 906 patients with depressive symptoms were included. PPSP improved depression compared with placebo [SMD: -0.39 (95%CI: -0.60 to -0.17); P < 0.001]. PPSP resulted in significant reductions in Hamilton Depression Rating Scale [MD: -1.72 (95%CI: -2.57 to -0.88); P < 0.001] and Beck Depression Inventory [MD: -2.69 (95%CI: -4.67 to -0.71); P < 0.001] scores. Sub-analysis confirmed the antidepressant effects of probiotics on depressive symptoms [SMD: -0.32 (95%CI: -0.48 to -0.16); P < 0.001], with prebiotics exerting no apparent effect [SMD: -0.08 (95%CI: -0.39 to -0.23); P = 0.62], and synbiotics exerting statistically significant benefits [SMD: -1.09 (95%CI: -1.45 to -0.73); P < 0.001].

CONCLUSION

PPSP effectively alleviates depressive symptoms, and subgroup analysis supports the benefits of probiotics and synbiotics. Nevertheless, evidence supporting the use of PPSP for the treatment of depression remains insufficient.

Beyond organ isolation: The bidirectional crosstalk between cerebral and intestinal ischemia-reperfusion injury via microbiota-gut-brain axis

Ischemia-reperfusion injury (IRI) represents a pathophysiological phenomenon of profound clinical relevance that poses considerable threats to patient safety. IRI may manifest in a variety of clinical contexts including, but not limited to, sepsis, organ transplantation, shock, myocardial infarction, cerebral ischemia, and stroke. Critically, IRI exhibits complex interactions across different organs, with effects that surpass mere localized tissue damage. These impacts can amplify damage to both adjacent and remote organs through pathways such as the gut-brain axis and the gut-lung axis, facilitated by intricate signaling mechanisms. Noteworthy is the interaction between gut IRI and brain IRI, which involves sophisticated neuroendocrine, systemic, and immune mechanisms coordinated through the microbiome-gut-brain axis. This review seeks to delve into the intricate interactions between gut and brain IRI, viewed through the lens of the microbiota-gut-brain axis. It aims to assess its translational potential in clinical settings, provide a theoretical foundation for developing relevant therapeutic strategies, and pinpoint novel directions for research.

The biological and sociological implications of diversity, equity, and inclusion (DEI): life within microbiomes and on earth

From a biological point of view, Diversity, Equity, and Inclusion (DEI) are important at multiple levels, which include our genetics, microbiomes, diets, and all organ system interactions. Considering only DEI's sociological aspects is equivalent to the error of "throwing out the baby with the bath water." Variances in microbial diversity within our microbiomes might affect our health through systemic interactions affecting metabolites, maintaining immune homeostasis, and wound healing of cellular damage from an infection, physical stress, or psychological trauma. An imbalance of our immune cell subsets, both innate and adaptive, and the microbes in any of our microbiomes might lead to more cellular damage from excessive inflammation and oxidative stress and less immune regulation. The immune dysregulation may occur due to the loss of endometrial barriers enabling the spread of microbes, environmental pollutants, and allergens. Heat waves, sleep deprivation, and increased prevalence of pollutants such as polychlorinated biphenyls, which weaken endothelial barriers, may be responsible for the enhanced prevalence of physical and psychological stresses. Leakage of our useful gut microbiota into the periphery might initiate inflammatory responses, and an altered gut microbiome might affect the gut-brain axis that influences physical and mental health.

Circadian attributes of neurological and psychiatric disorders as basis for their medication chronotherapy

This review focuses on (i) 24 h patterns in the symptom intensity of common neurologic and psychiatric disorders and (ii) medications prescribed for their management that have a recommended administration time or schedule, presumably to potentiate desired and minimize undesired effects and by definition qualify them as chronotherapies. Predictable-in-time patterning of symptoms is exhibited by many neurologic - headaches, multiple sclerosis, neurogenic orthostatic hypotension, neuropathic pain, Parkinson's disease, epileptic seizure, attention deficit hyperactivity, Alzheimer's disease - and psychiatric - eating, depressive, obsessive-compulsive, post-traumatic stress, anxiety, and panic - disorders, due either to circadian rhythms of disease pathophysiology or inadequacies of medication-delivery systems. Circadian disruption and circadian misalignment of the sleep-wake and other 24 h rhythms plus late chronotype are characteristic of many of these disorders, suggesting involvement in the mechanisms or consequence of their pathology or as an adverse effect of therapy, especially when administered at an inappropriate biological time. The Prescribers' Digital Reference, a compendium of all prescription medications approved for marketing in the US, reveals 65 of them are utilized to manage neurologic and psychiatric disorders by a recommended specified time-of-day or an asymmetrical interval or strength of dose schedule, presumably to optimize beneficial and minimize adverse effects, thereby qualifying them as chronotherapies. Overall, the contents of this review are intended to inform the development of future chronotherapies that incorporate state-of-the-art drug-delivery systems to improve management of neurologic and psychiatric disorders and associated circadian malalignment and disruption.

Gut Microbiota: A New Challenge in Mood Disorder Research

The gut microbiome has emerged as a novel and intriguing focus in mood disorder research. Emerging evidence demonstrates the significant role of the gut microbiome in influencing mental health, suggesting a bidirectional communication between the gut and the brain. This review examines the latest findings on the gut-microbiota-brain axis and elucidates how alterations in gut microbiota composition can influence this axis, leading to changes in brain function and behavior. Although dietary interventions, prebiotics, probiotics, and fecal microbiota transplantation have yielded encouraging results, significant advances are needed to establish next-generation approaches that precisely target the neurobiological mechanisms of mood disorders. Future research must focus on developing personalized treatments, facilitated by innovative therapies and technological progress, which account for individual variables such as age, sex, drug history, and lifestyle. Highlighting the potential therapeutic implications of targeting the gut microbiota, this review emphasizes the importance of integrating microbiota research into psychiatric studies to develop more effective and personalized treatment strategies for mood disorders.

Greater Symptom Burden and Poorer Quality of Life Outcomes Are Associated With The Co-Occurrence of Anxiety and Depression During Cancer Chemotherapy

OBJECTIVES

Anxiety and depression are common symptoms in oncology patients undergoing chemotherapy. Study purpose was to evaluate for differences in severity of common symptoms (ie, fatigue, energy, sleep disturbance, cognitive function, pain) and quality of life (QOL) outcomes among three subgroups of oncology outpatients with distinct joint anxiety and depression profiles.

METHODS

Oncology outpatients (N = 1328) completed measures of state anxiety and depression, six times over two cycles of chemotherapy. Latent profile analysis was done to identify subgroups of patients with distinct joint state anxiety AND depression profiles. Patients completed measures of trait anxiety, morning and evening fatigue, morning and evening energy, sleep disturbance, cognitive function, and pain, as well as generic and disease-specific measures of QOL at enrollment. Differences among the classes in symptom severity scores and QOL scores were evaluated using parametric and non-parametric tests.

RESULTS

Three distinct joint anxiety AND depression profiles were identified and named: Low Anxiety and Low Depression (57.5%, Both Low), Moderate Anxiety and Moderate Depression (33.7%, Both Moderate), and High Anxiety and High Depression (8.8%, Both High). All of the symptom severity scores showed a "dose-response effect" (ie, as the joint anxiety AND depression profiles worsened, the severity of all of the symptoms increased). Likewise, for both the general and disease-specific QOL (except spiritual well-being) measures, all of the scores decreased as the joint anxiety AND depression profiles worsened. Compared to the Both Low classes, the other two classes reported lower scores for the spiritual well-being domain.

CONCLUSIONS

More than 40% of patients receiving chemotherapy experience moderate to high levels of both anxiety AND depression. These patients report an extremely high symptom burden and significant decrements in all domains of QOL.

IMPLICATIONS FOR NURSING PRACTICE

Clinicians need to perform comprehensive assessments of depression and anxiety and other common symptoms and QOL outcomes during chemotherapy. In addition, referrals for targeted interventions are needed to manage multiple symptoms and improve patients' QOL.

Gut-Brain Axis and Brain Microbiome Interactions from a Medical Perspective

Background: The gut microbiome directly impacts brain health and activity, meaning the two are closely associated. This relationship suggests a link between microbial imbalances and diseases such as Alzheimer's, although multiple other contributing factors, such as genetics, also play a part. Additionally, recent studies discovered that cerebrospinal fluid has some microbial deoxyribonucleic acid (DNA), which can be interpreted to mean a microbiome exists in the brain too. The vagus nerve and the central nervous and immune systems are responsible for the connection between the brain and gut microbiome. Aims and Objectives: The main aim of this systematic review is to analyze existing research on the gut-brain axis and the brain microbiome to fill the current knowledge gap. Materials and Methods: A search was conducted on the PubMed database based on a set of predefined MeSH terms. Results: After the search, 2716 articles meeting the MeSH parameters were found in PubMed. This list was then downloaded and analyzed according to the inclusion/exclusion criteria, and 63 relevant papers were selected. Discussion: Bacteria in the gut microbiome produce some substances that are considered neuroactive. These compounds can directly or indirectly affect brain function through the gut-brain axis. However, various knowledge gaps on the mechanisms involved in this connection need to be addressed first.

Vagus nerve stimulation and gut microbiota interactions: A novel therapeutic avenue for neuropsychiatric disorders

The rising prevalence of treatment-resistant neuropsychiatric disorders underscores the need for innovative and effective treatment strategies. The gut microbiota (GM) plays a pivotal role in the progression of these diseases, influencing the brain and mental health through the gut-brain axis (GBA). The vagus nerve plays a significant role in the GBA, making it a key area of focus for potential novel therapeutic interventions. Vagus nerve stimulation (VNS) was introduced and approved as a treatment for refractory forms of some neuropsychological disorders, such as depression and epilepsy. Considering its impact on several brain regions that play a vital part in mood, motivation, affection, and cognitive function, the VNS has shown significant therapeutic potential for treating a variety of neuropsychiatric disorders. Using VNS to target the bidirectional communication pathways linking the GM and the VN could present an exciting and novel approach to treating neuropsychological disorders. Imbalances in the GM, such as dysbiosis, can impair the communication pathways between the gut and the brain, contributing to the development of neuropsychological disorders. VNS shows potential for modulating these interconnected systems, helping to restore balance. Interestingly, the composition of the GM may also influence the effectiveness of VNS, as it has the potential to modify the brain's response to this therapeutic approach. This study provides a comprehensive analysis of a relatively unexplored but noteworthy interaction between VNS and GM in the treatment of neuropsychiatric disorders. In addition, we discussed the mechanisms, therapeutic potential, and clinical implications of VNS on the GBA across neuropsychiatric disorders.

Association between the dietary inflammatory index and depressive symptoms in adults with metabolic syndrome: a cross-sectional study from the NHANES database

Objective

The comorbidity of metabolic syndrome (MS) and depressive symptoms has emerged as a growing public health concern, contributing to a substantial global economic burden. The pathogenesis of this comorbidity is thought to be closely linked to inflammation. However, research examining the impact of the Dietary Inflammatory Index (DII) on depressive symptoms in adults with MS remains limited. This study aims to investigate the association between the DII and depressive symptoms in adults with MS, utilizing data from the National Health and Nutrition Examination Survey (NHANES).

Methods

This cross-sectional study included 7,553 participants aged 20 and older MS from six cycles of the NHANES (2007-2018). Depressive symptoms were assessed using the Patient Health Questionnaire scores, and dietary information was gathered to calculate the Dietary Inflammatory Index (DII). The association between DII scores and depressive symptoms in individuals with MS was evaluated through multivariable logistic regression analysis, adjusting for relevant covariates. Subgroup analyses and restricted cubic splines (RCS) were performed to explore this relationship further.

Results

Among the participants, 907 individuals (12.0%) were identified as having depressive symptoms. After adjusting for all covariates, a positive correlation was observed (OR = 1.09, 95% CI: 1.04-1.14). After adjusting for all covariates, a positive association was observed between DII scores and depressive symptoms (OR = 1.09, 95% CI: 1.04-1.14). Individuals in the highest tertile of DII scores had significantly higher odds of depressive symptoms compared to those in the lowest tertile (OR = 1.36, 95% CI: 1.13-1.65). Subgroup analyses revealed that men were more likely to experience depressive symptoms among adults with MS. The RCS model revealed a nonlinear positive association between DII scores and depressive symptoms in these participants.

Conclusion

Our study indicates that the DII is positively correlated with an increased likelihood of depressive symptoms among adults with MS in the United States. These findings align with existing research and necessitate further validation through prospective cohort studies.

Beyond digestion: Exploring how the gut microbiota modulates human social behaviors

For a long time, traditional medicine has acknowledged the gut's impact on general health. Contemporary science substantiates this association through investigations of the gut microbiota, the extensive community of microorganisms inhabiting our gastrointestinal system. These microscopic residents considerably improve digestive processes, nutritional absorption, immunological function, and pathogen defense. Nevertheless, a variety of gastrointestinal and extra-intestinal disorders can result from dysbiosis, an imbalance of the microbial composition of the gut microbiota. A groundbreaking discovery is the gut-brain axis, a complex communication network that links the enteric and central nervous system (CNS). This bidirectional communication allows the brain to influence gut activities and vice versa, impacting mental health and mood disorders like anxiety and depression. The gut microbiota can influence this communication by creating neurotransmitters and short-chain fatty acids, among other biochemical processes. These factors may affect our mental state, our ability to regulate our emotions, and the hypothalamic-pituitary-adrenal (HPA) axis. This study aimed to explore the complex interrelationships between the brain and the gut microbiota. We also conducted a thorough examination of the existing understanding in the area of how microbiota affects social behaviors, including emotions, stress responses, and cognitive functions. We also explored the potential of interventions that focus on the connection between the gut and the brain, such as using probiotics to treat diseases of the CNS. This research opens up new possibilities for addressing mental health and neurological conditions in an innovative manner.

Probiotics and Food Bioactives: Unraveling Their Impact on Gut Microbiome, Inflammation, and Metabolic Health

This review paper delves into the role of probiotics and food bioactives in influencing gut health and overall well-being, within the context of probiotics and food bioactives, emphasizing their roles in modulating inflammation, gut microbiota, and metabolic health. Probiotics are defined as live microorganisms that confer health benefits to the host, primarily through their impact on the gut microbiome; a complex community of microorganisms crucial for maintaining health. The review aims to elucidate how probiotics, incorporated into both traditional and modern food systems, can enhance gut health and address metabolic disorders. It examines the types of probiotics present in various foods and their mechanisms of action, including their effects on immune function and metabolic health. By exploring the links between probiotics and health outcomes such as digestive health, immune support, and mental health, the review identifies specific conditions where probiotics show significant promise. Hurldes such as inconsistencies in research findings, variability in probiotic strains, and dosages are addressed. The paper also suggests future research directions, including the potential for personalized probiotic interventions. The review concludes by summarizing key findings and emphasizing the critical role of probiotics in food systems for promoting overall health and mitigating metabolic diseases.

A probiotic NVP1704 alleviates stress-induced sleeplessness/depression-like symptoms in mice by upregulating serotonergic and GABAergic systems and downregulating NF-κB activation

Sleeplessness (insomnia) is a potential symptom of depression. A probiotic NVP1704 alleviates depression-like behavior and neuroinflammation in mice. Therefore, to understand whether NVP1704 could be effective against sleeplessness in vivo, we exposed immobilization stress (IS) in mice, then orally administered NVP1704 for 5 days, and assayed depression/anxiety-like behavior in the open field, elevated plus maze, and tail suspension tests, sleeping latency time, and sleep duration, euthanized then by exposure to CO2, and analyzed their related biomarkers. Oral administration of NVP1704 decreased IS-induced depression/anxiety-like behavior and sleeping latency time and increased IS-suppressed sleeping duration. NVP1704 increased IS-suppressed expression of γ-aminobutyric acid (GABA), GABAA receptor α1 (GABAARα1) and α2 subunits (GABAARα2), serotonin, 5-HT receptors (5-HT1AR and 5-HT1BR), and melatonin receptors (MT1R and MT2R) in the prefrontal cortex and thalamus. NVP1704 also increased the IS-suppressed GABAARα1-positive cell population in the prefrontal cortex and decreased IS-induced corticosterone, TNF-α, and IL-6 expression and the NF-κB+Iba1+ cell population in the brain and myeloperoxidase, TNF-α, and IL-6 expression and the NF-κB+CD11c+ cell population in the colon. Based on these findings, NVP1704 may alleviate depression/anxiety/sleeplessness-like behaviors through the upregulation of serotonergic and GABAergic systems and downregulation of NF-κB activation.