Interaction between BDNF and serotonin: role in mood disorders

Brain region-specific roles of brain-derived neurotrophic factor in social stress-induced depressive-like behavior

Brain-derived neurotrophic factor is a key factor in stress adaptation and avoidance of a social stress behavioral response. Recent studies have shown that brain-derived neurotrophic factor expression in stressed mice is brain region-specific, particularly involving the corticolimbic system, including the ventral tegmental area, nucleus accumbens, prefrontal cortex, amygdala, and hippocampus. Determining how brain-derived neurotrophic factor participates in stress processing in different brain regions will deepen our understanding of social stress psychopathology. In this review, we discuss the expression and regulation of brain-derived neurotrophic factor in stress-sensitive brain regions closely related to the pathophysiology of depression. We focused on associated molecular pathways and neural circuits, with special attention to the brain-derived neurotrophic factor-tropomyosin receptor kinase B signaling pathway and the ventral tegmental area-nucleus accumbens dopamine circuit. We determined that stress-induced alterations in brain-derived neurotrophic factor levels are likely related to the nature, severity, and duration of stress, especially in the above-mentioned brain regions of the corticolimbic system. Therefore, BDNF might be a biological indicator regulating stress-related processes in various brain regions.

Psychological stressors involved in the pathogenesis of premature ovarian insufficiency and potential intervention measures

Premature ovarian insufficiency (POI) is a common gynecological endocrine disease, which seriously affects women's physical and mental health and fertility, and its incidence is increasing year by year. With the development of social economy and technology, psychological stressors such as anxiety and depression caused by social, life and environmental factors may be one of the risk factors for POI. We used PubMed to search peer-reviewed original English manuscripts published over the last 10 years to identify established and experimental studies on the relationship between various types of stress and decreased ovarian function. Oxidative stress, follicular atresia, and excessive activation of oocytes, caused by Stress-associated factors may be the main causes of ovarian function damage. This article reviews the relationship between psychological stressors and hypoovarian function and the possible early intervention measures in order to provide new ideas for future clinical treatment and intervention.

Early-life manipulation of the serotonergic system exacerbates the harmful effects of sleep deprivation on cognitive functions

Serotonin is a monoamine neurotransmitter that plays a main role in regulating physiological and cognitive functions. Serotonergic system dysfunction is involved in the etiology of various psychiatric and neurological disorders. Therefore, the present study was designed to investigate the effects of early-life serotonin depletion on cognitive disorders caused by sleep deprivation. Serotonin was depleted by para-chlorophenylalanine (PCPA, 100 mg/kg, s.c.) at postnatal days 10-20, followed by sleep deprivation-induced through the multiple platform apparatus for 24 h at PND 60. After the examination of the novel object recognition and passive avoidance memories, the hippocampi and prefrontal cortex were dissected to examine the brain-derived neurotrophic factor (BDNF) mRNA expression by PCR. Our findings showed that postnatal serotonin depletion and sleep deprivation impaired the novel object recognition and passive avoidance memories and changed the BDNF levels. In the same way, the serotonin depletion in early life before sleep deprivation exacerbated the harmful effects of sleep deprivation on cognitive function and BDNF levels. It can be claimed that the serotonergic system plays a main role in the modulation of sleep and cognitive functions.

The effect of antidepressant treatment on blood BDNF levels in depressed patients: A review and methodological recommendations for assessment of BDNF in blood

Major depressive disorder (MDD) is a highly prevalent psychiatric disorder and a leading cause of disability worldwide. Brain-derived neurotrophic factor (BDNF), a signaling protein responsible for promoting neuroplasticity, is highly expressed in the central nervous system but can also be found in the blood. Since impaired brain plasticity is considered a cornerstone in the pathophysiology of MDD, measurement of BDNF in blood has been proposed as a potential biomarker in MDD. The aim of our study is to systematically review the literature for the effects of antidepressant treatments on blood BDNF levels in MDD and the suitability of blood BDNF as a biomarker for depression severity and antidepressant response. We searched Pubmed® and Cochrane library up to March 2024 in a systematic manner using Medical Subject Headings (MeSH). The search resulted in a total of 42 papers, of which 30 were included in this systematic review. Generally, we found that patients with untreated MDD have a lower blood BDNF level than healthy controls. Antidepressant treatments increase blood BDNF levels, and more evidently after pharmacological than non-pharmacological treatment. Neither baseline nor change in the blood BDNF level correlates with depression severity or treatment outcome, which undermines its use as a biomarker in MDD. Our review also highlights the importance of considering factors influencing the accuracy and reproducibility of BDNF measurements. We summarize considerations to help obtain more robust blood BDNF values and compile a list of recommendations to help streamline assessment of blood BDNF levels in future studies.

Unlocking the Potential of Probiotics: A Comprehensive Review on Research, Production, and Regulation of Probiotics

This review provides a comprehensive overview of the current state of probiotic research, covering a wide range of topics, including strain identification, functional characterization, preclinical and clinical evaluations, mechanisms of action, therapeutic applications, manufacturing considerations, and future directions. The screening process for potential probiotics involves phenotypic and genomic analysis to identify strains with health-promoting properties while excluding those with any factor that could be harmful to the host. In vitro assays for evaluating probiotic traits such as acid tolerance, bile metabolism, adhesion properties, and antimicrobial effects are described. The review highlights promising findings from in vivo studies on probiotic mitigation of inflammatory bowel diseases, chemotherapy-induced mucositis, dysbiosis, obesity, diabetes, and bone health, primarily through immunomodulation and modulation of the local microbiota in human and animal models. Clinical studies demonstrating beneficial modulation of metabolic diseases and human central nervous system function are also presented. Manufacturing processes significantly impact the growth, viability, and properties of probiotics, and the composition of the product matrix and supplementation with prebiotics or other strains can modify their effects. The lack of regulatory oversight raises concerns about the quality, safety, and labeling accuracy of commercial probiotics, particularly for vulnerable populations. Advancements in multi-omics approaches, especially probiogenomics, will provide a deeper understanding of the mechanisms behind probiotic functionality, allowing for personalized and targeted probiotic therapies. However, it is crucial to simultaneously focus on improving manufacturing practices, implementing quality control standards, and establishing regulatory oversight to ensure the safety and efficacy of probiotic products in the face of increasing therapeutic applications.

Evidence for the Contribution of the miR-206/BDNF Pathway in the Pathophysiology of Depression

Depression is a complex disorder with substantial impacts on individual health and has major public health implications. Depression results from complex interactions between genetic and environmental factors. Epigenetic mechanisms, including DNA methylation, microRNAs (miRNAs), and histone modifications, can produce heritable phenotypic changes without a change in DNA sequence and recently were proven to mediate lasting increases in the risk of depression following exposure to adverse life events. Of these, miRNAs are gaining attention for their role in the pathogenesis of many stress-associated mental disorders, including depression. One such miRNA is microRNA-206 (miR-206), which is a critical candidate for increasing the susceptibility to stress. Although miR-206 is thought to be a typical muscle-specific miRNA, it is expressed throughout the brain, particularly in the hippocampus and prefrontal cortex. Until now, only a few studies have been conducted on rodents to understand the role of miR-206 in stress-related abnormalities in neurogenesis. However, the precise underlying molecular mechanism of miR-206-mediated depression-like behaviors remains largely unknown. Here, we reviewed recent advances in the field of biomedical and clinical research on the role of miR-206 in the pathogenesis of depression from studies using different tissues and various experimental designs and described how abnormalities in miR-206 expression in these tissues can affect neuronal functions. Moreover, we focused on studies investigating the brain-derived neurotrophic factor (BDNF) as a functional target of miR-206, where miR-206 has been implicated in the pathogenesis of depression by suppressing the expression of the BDNF. In summary, these studies confirm the existence of a tight correlation between the pathogenesis of depression and the miR-206/BDNF pathway.

The Relationship Between Brain-Derived Neurotrophic Factor and Serotonin in Major Depressive and Bipolar Disorders: A Cross-Sectional Analysis

Background Mood disorders like major depressive disorder (MDD) and bipolar disorder (BD) involve complex interactions between brain-derived neurotrophic factor (BDNF) and serotonin. While extensive research has explored these factors individually, their combined effects and interactions in these disorders are less understood. This study uniquely addresses this gap by examining how BDNF and serotonin interact and relate to mood disorder severity, providing new insights into their joint role in MDD and BD. Objectives The objective of this study was to examine the correlation between serum BDNF and plasma serotonin levels and to assess how these correlations relate to the severity of symptoms and overall disease severity in MDD and BD. Methodology This cross-sectional study, conducted at the Khyber Medical University, Peshawar, from January to September 2023, examined the correlation between BDNF and serotonin in individuals with MDD and BD. Participants (n = 63) aged 18-65 were recruited based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria, excluding those with neurological disorders, substance abuse, or severe medical illness. A control group of 21 healthy individuals was matched by age and gender. Data collection involved demographic details, clinical history, and comorbid diagnoses assessed using the Mini International Neuropsychiatric Interview (MINI). Mood disorder severity was measured using the Hamilton Depression Rating Scale (HAM-D) for MDD and the Young Mania Rating Scale (YMRS) for BD, along with additional assessments (Beck Depression Inventory, Global Assessment of Functioning). Serum BDNF and serotonin levels were analyzed using enzyme-linked immunosorbent assay (ELISA) kits. Statistical analyses included t-tests, Mann-Whitney U tests, Pearson correlations, and subgroup analyses to assess relationships between biomarkers, mood disorder severity, and influencing factors. Results BDNF levels were found to be 20.1 ± 5.3 ng/mL in MDD, 18.5 ± 4.7 ng/mL in BD, and 25.9 ± 6.2 ng/mL in controls. Serotonin levels were 45.8 ± 12.6 ng/mL in MDD, 43.2 ± 11.4 ng/mL in BD, and 52.1 ± 14.3 ng/mL in controls. In the MDD group, significant negative correlations were observed between BDNF levels and mood disorder severity (r = -0.32, p = 0.045), whereas serotonin levels did not show significant correlations (r = -0.21, p = 0.23). In the BD group, BDNF levels also showed a significant negative correlation with manic symptoms (r = -0.28, p = 0.048), but serotonin levels showed no significant correlation. Subgroup analyses revealed that participants under 40 years had higher BDNF levels (22.8 ± 5.6 ng/mL) compared to those aged 40 and above (19.7 ± 4.3 ng/mL). Females showed higher BDNF levels (24.5 ± 6.3 ng/mL) than males (19.3 ± 3.8 ng/mL). Participants not on medication had higher BDNF levels (23.6 ± 5.1 ng/mL) compared to those on medication (17.9 ± 4.2 ng/mL). Those without comorbidities also had higher BDNF levels (23.8 ± 5.9 ng/mL) than those with comorbidities (18.2 ± 4.5 ng/mL), while serotonin levels varied similarly across these subgroups. Conclusion Lower BDNF levels are associated with mood disorders and symptom severity, indicating their potential as a biomarker.

Docosahexaenoic acid supplementation and infant brain development: role of gut microbiome

Perinatal stage represents a critical period for brain development. Docosahexaenoic acid (DHA) is a ω-3 polyunsaturated fatty acid preferentially accumulated in the brain that may benefit neurodevelopment. Microbial colonization and maturation parallel with the rapid development of infant metabolic and brain function that may influence the effects of DHA on neurological development. This review aims to summarize the current literature on the mediating effects of DHA on brain and gut microbiome development and attempts to reevaluate the efficacy of DHA from a gut microbiome-mediated perspective. Specifically, the regulatory roles of DHA on hypothalamic-pituitary-adrenal axis, inflammation, and neuroactive mediators may be partly moderated through gut microbiome. Consideration of the gut microbiome and gut-brain communication, when evaluating the efficacy of DHA, may provide new insights in better understanding the mechanisms of DHA and impart advantages to future development of nutritional therapy based on the nutrient-microbiome interaction.

"A systematic review of risk factors of postpartum depression. Evidence from Asian culture "

OBJECTIVES

One of the largest health concerns, postpartum depression (PPD), has detrimental effects on new mothers, their child, and their family. Investigating under-researched risk factors for postpartum depression in Asian women is the goal of this review of the literature.

METHODS

The literature was searched using a number of electronic research databases. This review included studies that meet the following requirements: (a) they evaluated risk variables; (b) they were conducted in Asian countries using quantitative or qualitative methods; and (c) they were published in English in peer-reviewed journals between 2007 and 2023. A total of 90 studies from 14 different countries were reviewed, compiled, and synthesized.

RESULTS

In Asian countries, where rates ranged from 0.82 % to 93 %, South Korea and Japan had the lowest and highest rates of postpartum depression, respectively. The risk factors for postpartum depression were divided into five main categories: biological/physical (e.g., ABO blood group, oxytocin level), psychological (e.g., antenatal depression, body dissatisfaction, child care stress), obstetric/pediatric (e.g., loss of baby, abortions, pain), socio-demographic (e.g., low social support, poverty, loss of autonomy), and cultural (e.g., gender preference).

CONCLUSION

This phenomenon is prevalent in Asian cultures as it is in European Countries. The repercussions of untreated postpartum depression can lead to long-term psychological and developmental issues in children and strain the familial bonds essential for a nurturing environment. Moreover, understanding the specific risk factors faced by Asian women can pave the way for culturally sensitive interventions and support systems designed to address and mitigate these challenges effectively.

Inhibition of 5-HT alleviates PTSD-like behaviors and promotes hippocampal neuroplasticity by modulating hippocampal autophagy in rats

5-Hydroxytryptamine (5-HT) plays a substantial role in mitigating depression and anxiety. However, the potential effects of 5-HT against posttraumatic stress disorder (PTSD) and its underlying mechanisms remain unclear. Elevated plus maze test evaluates anxiety-related behaviors, and the open field test is used to assess overall activity levels and anxiety. Inflammatory cytokine levels were determined using ELISA. The levels of 5-HT and dopamine were measured using HPLC. mRNA and protein levels were examined by PCR and Western blot, respectively. Rats exposed to single prolonged stress (SPS) exhibited typical PTSD-like phenotypes, with decreased levels of 5-HT in the hippocampus and significant reductions in its downstream targets, brain-derived neurotrophic factor (BDNF) and TrkB. In addition, it was discovered that the autophagy signaling pathway might be involved in regulating hippocampal BDNF in rats exposed to SPS. Subsequent treatment with an intracerebral injection of sh-SERT significantly inhibited anxiety and cognitive dysfunction in rats. Moreover, sh-SERT treatment was observed to substantially reverse the increase in autophagy signaling protein expression and consequently improve the expression of BDNF and TrkB proteins, which had been reduced. The current study demonstrates that sh-SERT exhibits significant anti-PTSD effects, potentially mediated in part through the reduction of cellular autophagy to enhance hippocampal synaptic plasticity.NEW & NOTEWORTHY The study demonstrated that sh-SERT exhibits significant anti-posttraumatic stress disorder (PTSD) effects, potentially mediated in part through the reduction of cellular autophagy to enhance hippocampal synaptic plasticity.

Modulation of Brain-derived Neurotrophic Factor Expression by Physical Exercise in Reserpine-induced Pain-depression Dyad in Mice

Pain accompanied by depressive symptoms is a common reason for seeking medical assistance, and many chronic pain patients experience comorbid depression. The brain-derived neurotrophic factor (BDNF) is a well-known neurotrophin expressed throughout the nervous system, playing a crucial role in neuronal growth and neuroplasticity. This study aimed to examine the effects of exercise on BDNF expression in the nervous system and reserpine (RSP)-induced pain-depression dyad. RSP (1 mg/kg) was subcutaneously administered once daily for three days in mice. The exercise was performed using a rota-rod tester for seven consecutive days following RSP administration. Pain responses were evaluated using von Frey filaments, and depression-like behaviors were assessed through forced swimming and open field tests. Immunofluorescence staining was performed to examine the changes in BDNF expression in the dorsal root ganglion (DRG), spinal cord, and hippocampus. Administration of RSP reduced mechanical paw withdrawal threshold, increased immobility time in the forced swimming test, and decreased movement in the open field test. The immunoreactivity of BDNF was increased in the DRG and spinal dorsal regions, and decreased in the hippocampus after RSP administration. Physical exercise significantly reduced the RSP-induced mechanical hypersensitivity and depression-like behaviors. In addition, exercise suppressed not only the increased expression of BDNF in the DRG and spinal dorsal regions but also the decreased expression of BDNF in the hippocampus induced by RSP administration. These findings suggest that repetitive exercise could serve as an effective and non-invasive treatment option for individuals experiencing both pain and depression by modulating BDNF expression.

Indirect influence on the BDNF/TrkB receptor signaling pathway via GPCRs, an emerging strategy in the treatment of neurodegenerative disorders

Neuronal survival depends on neurotrophins and their receptors. There are two types of neurotrophin receptors: a nonenzymatic, trans-membrane protein of the tumor necrosis factor receptor (TNFR) family-p75 receptor and the tyrosine kinase receptors (TrkR) A, B, and C. Activation of the TrkBR by brain-derived neurotrophic factor (BDNF) or neurotrophin 4/5 (NT-4/5) promotes neuronal survival, differentiation, and synaptic function. It is shown that in the pathogenesis of several neurodegenerative conditions (Alzheimer's disease, Parkinson's disease, Huntington's disease) the BDNF/TrkBR signaling pathway is impaired. Since it is known that GPCRs and TrkR are regulating several cell functions by interacting with each other and generating a cross-communication in this review we have focused on the interaction between different GPCRs and their ligands on BDNF/TrkBR signaling pathway.

Neural underpinnings of fine motor skills under stress and anxiety: A review

This review offers a comprehensive examination of how stress and anxiety affect motor behavior, particularly focusing on fine motor skills and gait adaptability. We explore the role of several neurochemicals, including brain-derived neurotrophic factor (BDNF) and dopamine, in modulating neural plasticity and motor control under these affective states. The review highlights the importance of developing therapeutic strategies that enhance motor performance by leveraging the interactions between key neurochemicals. Additionally, we investigate the complex interplay between emotional-cognitive states and sensorimotor behaviors, showing how stress and anxiety disrupt neural integration, leading to impairments in skilled movements and negatively impacting quality of life. Synthesizing evidence from human and rodent studies, we provide a detailed understanding of the relationships among stress, anxiety, and motor behavior. Our findings reveal neurophysiological pathways, behavioral outcomes, and potential therapeutic targets, emphasizing the intricate connections between neurobiological mechanisms, environmental factors, and motor performance.

Levels of brain-derived neurotrophic factor (BDNF) among patients with COVID-19: a systematic review and meta-analysis

Many individuals have been suffering from consistent neurological and neuropsychiatric manifestations even after the remission of coronavirus disease (COVID-19). Brain-derived neurotrophic factor (BDNF) is a protein involved in the regulation of several processes, including neuroplasticity, neurogenesis, and neuronal differentiation, and has been linked to a range of neurological and psychiatric disorders. In this study, we aimed to synthesize the available evidence on the profile of BDNF in COVID-19. A comprehensive search was done in the Web of Science core collection, Scopus, and MEDLINE (PubMed), and Embase to identify relevant studies reporting the level of BDNF in patients with COVID-19 or those suffering from long COVID. We used the NEWCASTLE-OTTAWA tool for quality assessment. We pooled the effect sizes of individual studies using the random effect model for our meta-analysis. Fifteen articles were included in the systematic review. The sample sizes ranged from 16 to 183 participants. Six studies compared the level of BDNF in COVID-19 patients with healthy controls. The pooled estimate of the standardized mean difference in BDNF level between patients with COVID-19 and healthy individuals was - 0.84 (95% CI - 1.49 to - 0.18, p = 0.01, I2 = 81%) indicating a significantly lower BDNF level in patients with COVID-19. Seven studies assessed BDNF in different severity statuses of patients with COVID-19. The pooled estimate of the standardized mean difference in BDNF level was - 0.53 (95% CI - 0.85 to - 0.21, p = 0.001, I2 = 46%), indicating a significantly lower BDNF level in patients with more severe COVID-19. Three studies evaluated BDNF levels in COVID-19 patients through different follow-up periods. Only one study assessed the BDNF levels in long COVID patients. Sensitivity analyses did not alter the significance of the association. In this study, we showed a significant dysregulation of BDNF following COVID-19 infection. These findings may support the pathogenesis behind the long-lasting effects of this disease among infected patients. PROSPERO: CRD42023413536.

10 weeks low intensity treadmill exercise intervention ameliorates motor deficits and sustains muscle mass via decreasing oxidative damage and increasing mitochondria function in a rat model of Parkinson's disease

AIMS

Parkinson's disease (PD) is characterized by loss of dopamine neurons in the brain, which leads to motor dysfunction; excessive inflammation induces neuronal death. This study aimed to determine the most effective exercise modality to improve motor dysfunction in PD by comparing three different exercise regimens (low-intensity treadmill, high-intensity treadmill, and swimming).

MATERIALS AND METHODS

The rat model for PD was established through stereotaxic surgery, inducing unilateral 6-OHDA (6-hydroxydopamine) lesions. The low-intensity treadmill regimen exerted better protective effects on neurological and motor functions in a rat model of unilateral 6-OHDA-induced PD compared to high-intensity treadmill and swimming. The most suitable exercise regimen and the optimal duration of daily exercise (15 or 30 min) on motor activity and oxidative stress parameters were evaluated.

KEY FINDINGS

Comparison of 15 and 30 min low-intensity treadmill regimens (10 m/min) revealed 30 min daily exercise was the optimal duration and had more favorable impacts on neurological and motor function. Furthermore, we assessed the neuroprotective effects of exercising for 15 and 30 min per day for either four or ten weeks; 30 min of daily exercise for ten weeks improved mitochondrial function, the antioxidant defense system, neurotrophic factors, and muscle mass, and thereby provided protection against dopaminergic neuron loss, and motor dysfunction in rats with 6-OHDA-induced PD.

SIGNIFICANCE

30 min of daily low-intensity treadmill exercise over 10 weeks resulted in heightened mitochondrial function in both muscle and brain tissues, therefore, yielded a neuroprotective effect against the loss of dopaminergic neurons and motor dysfunction in PD rats.

Anxiolytic Action of Dipeptide Mimetic of the BDNF Loop 2 in Adult Animals

We studied the anti-anxiety effect of a low-molecular-weight mimetic of the BDNF loop 2, hexamethylenediamide bis-(-N-hexanoyl-L-seryl-L-lysine) (GTS-201) in adult animals. GTS-201 at a dose of 5 mg/kg after acute intraperitoneal administration to outbred male and female rats increased the time spent in the open arms and the number of entries into the open arms in the elevated plus maze (EPM). In "highly emotional" male BALB/c mice, GTS-201 exhibited a dose-dependent anxiolytic effect in the EPM in a dose range of 0.5-2.0 mg/kg with a maximum effective dose of 1 mg/kg. These data confirm the previously revealed anti-anxiety properties of GTS-201 in inbred male and female BALB/c mice and rats and indicate the dependence of the pharmacological activity of the BDNF mimetic on animal age.

Exploring the Multifaceted Therapeutic Potential of Probiotics: A Review of Current Insights and Applications

The interplay between human health and the microbiome has gained extensive attention, with probiotics emerging as pivotal therapeutic agents due to their vast potential in treating various health issues. As significant modulators of the gut microbiota, probiotics are crucial in maintaining intestinal homeostasis and enhancing the synthesis of short-chain fatty acids. Despite extensive research over the past decades, there remains an urgent need for a comprehensive and detailed review that encapsulates probiotics' latest insights and applications. This review focusses on the multifaceted roles of probiotics in promoting health and preventing disease, highlighting the complex mechanisms through which these beneficial bacteria influence both gut flora and the human body at large. This paper also explores probiotics' neurological and gastrointestinal applications, focussing on their significant impact on the gut-brain axis and their therapeutic potential in a broad spectrum of pathological conditions. Current innovations in probiotic formulations, mainly focusing on integrating genomics and biotechnological advancements, have also been comprehensively discussed herein. This paper also critically examines the regulatory landscape that governs probiotic use, ensuring safety and efficacy in clinical and dietary settings. By presenting a comprehensive overview of recent studies and emerging trends, this review aims to illuminate probiotics' extensive therapeutic capabilities, leading to future research and clinical applications. However, besides extensive research, further advanced explorations into probiotic interactions and mechanisms will be essential for developing more targeted and effective therapeutic strategies, potentially revolutionizing health care practices for consumers.

An Expanded Narrative Review of Neurotransmitters on Alzheimer's Disease: The Role of Therapeutic Interventions on Neurotransmission

Alzheimer's disease (AD) is a progressive neurodegenerative disease. The accumulation of amyloid-β (Aβ) plaques and tau neurofibrillary tangles are the key players responsible for the pathogenesis of the disease. The accumulation of Aβ plaques and tau affect the balance in chemical neurotransmitters in the brain. Thus, the current review examined the role of neurotransmitters in the pathogenesis of Alzheimer's disease and discusses the alterations in the neurochemical activity and cross talk with their receptors and transporters. In the presence of Aβ plaques and neurofibrillary tangles, changes may occur in the expression of neuronal receptors which in turn triggers excessive release of glutamate into the synaptic cleft contributing to cell death and neuronal damage. The GABAergic system may also be affected by AD pathology in a similar way. In addition, decreased receptors in the cholinergic system and dysfunction in the dopamine neurotransmission of AD pathology may also contribute to the damage to cognitive function. Moreover, the presence of deficiencies in noradrenergic neurons within the locus coeruleus in AD suggests that noradrenergic stimulation could be useful in addressing its pathophysiology. The regulation of melatonin, known for its effectiveness in enhancing cognitive function and preventing Aβ accumulation, along with the involvement of the serotonergic system and histaminergic system in cognition and memory, becomes remarkable for promoting neurotransmission in AD. Additionally, nitric oxide and adenosine-based therapeutic approaches play a protective role in AD by preventing neuroinflammation. Overall, neurotransmitter-based therapeutic strategies emerge as pivotal for addressing neurotransmitter homeostasis and neurotransmission in the context of AD. This review discussed the potential for neurotransmitter-based drugs to be effective in slowing and correcting the neurodegenerative processes in AD by targeting the neurochemical imbalance in the brain. Therefore, neurotransmitter-based drugs could serve as a future therapeutic strategy to tackle AD.

Embryonic Zebrafish as a Model for Investigating the Interaction between Environmental Pollutants and Neurodegenerative Disorders

Environmental pollutants have been linked to neurotoxicity and are proposed to contribute to neurodegenerative disorders. The zebrafish model provides a high-throughput platform for large-scale chemical screening and toxicity assessment and is widely accepted as an important animal model for the investigation of neurodegenerative disorders. Although recent studies explore the roles of environmental pollutants in neurodegenerative disorders in zebrafish models, current knowledge of the mechanisms of environmentally induced neurodegenerative disorders is relatively complex and overlapping. This review primarily discusses utilizing embryonic zebrafish as the model to investigate environmental pollutants-related neurodegenerative disease. We also review current applicable approaches and important biomarkers to unravel the underlying mechanism of environmentally related neurodegenerative disorders. We found embryonic zebrafish to be a powerful tool that provides a platform for evaluating neurotoxicity triggered by environmentally relevant concentrations of neurotoxic compounds. Additionally, using variable approaches to assess neurotoxicity in the embryonic zebrafish allows researchers to have insights into the complex interaction between environmental pollutants and neurodegenerative disorders and, ultimately, an understanding of the underlying mechanisms related to environmental toxicants.

Platelet Levels of Brain-Derived Neurotrophic Factor in Adults with Autism Spectrum Disorder: Is There a Specific Association with Autism Spectrum Psychopathology?

To date, although several studies have investigated the circulating levels of brain-derived neurotrophic factor (BDNF) in children with autism spectrum disorder (ASD), only a few authors have addressed their evaluation in adults. Furthermore, an important limitation of these studies lies in the fact that circulating BDNF is stored in platelets and released into the circulation when needed. To the best of our knowledge, a very limited number of studies have related peripheral BDNF values to platelet counts, and yet no study has evaluated intra-platelet BDNF levels in adults with ASD. In this framework, the aim of the present work is to pave the way in this field and evaluate platelet BNDF levels in adult ASD patients, as well as their correlation with autistic symptoms and related psychopathological dimensions. We recruited 22 ASD and 22 healthy controls, evaluated with the Adult autism subthreshold spectrum (AdAS Spectrum), the Social Anxiety Spectrum-self report (SHY-SR), the Trauma and loss spectrum-self report (TALS-SR), the Work and Social Adjustment Scale (WSAS), and the Mood Spectrum-self report for suicidality. Intra-platelet BDNF levels were also assessed. The results highlighted lower BDNF levels in the ASD group; moreover, AdAS Spectrum and WSAS total score as well as AdAS Spectrum Restricted interest and rumination, WSAS Private leisure activities, TALS-SR Arousal, and SHY-SR Childhood domains were significant negative predictors of platelet BDNF levels.

An analysis of the relationship of "the Mozart effect" with BDNF levels in anatomy education

In 1993, an increase was observed in the spatial IQ scores of the volunteers who listened to Mozart's sonata K448 for 10 min, and this phenomenon entered the literature as the "Mozart effect." Other studies have shown that this effect is particularly evident in spatial skill tests. A large body of research has provided evidence that spatial ability is associated with success in learning anatomy. In this study, Kastamonu University Faculty of Medicine students were divided into two groups during 16-h practical training spanning 30 days. While one of the groups listened to Mozart's K448 sonata as the background music in all lessons, the control group attended the lessons in their standard form. At the end of each lesson, all students solved a modified mental rotation test including questions involving anatomical structures. Before starting the study, after the first laboratory class, on the 15th and 30th day of the study, blood samples were taken from the participants, and plasma brain-derived neurotrophic factor (BDNF) levels were determined. The effect of time on mental rotation score and plasma BDNF level was significant (p < 0.001 for both). The effect of group was also significant (p < 0.001 for both). Pairwise comparisons showed significance in the fifth, sixth, seventh, and eighth mental rotation test (p < 0.001, p = 0.041, p < 0.001, p < 0.001, respectively) and in the third (Day 15) and fourth (Day 30) BDNF measurement (p < 0.001 for both). Our findings may indicate that specific background music may be useful for anatomy teaching.

Role of Glial Cells in Neuronal Function, Mood Disorders, and Drug Addiction

Mood disorders and substance use disorder (SUD) are of immense medical and social concern. Although significant progress on neuronal involvement in mood and reward circuitries has been achieved, it is only relatively recently that the role of glia in these disorders has attracted attention. Detailed understanding of the glial functions in these devastating diseases could offer novel interventions. Here, following a brief review of circuitries involved in mood regulation and reward perception, the specific contributions of neurotrophic factors, neuroinflammation, and gut microbiota to these diseases are highlighted. In this context, the role of specific glial cells (e.g., microglia, astroglia, oligodendrocytes, and synantocytes) on phenotypic manifestation of mood disorders or SUD are emphasized. In addition, use of this knowledge in the potential development of novel therapeutics is touched upon.

Impact of Baduanjin exercise combined with rational emotive behavior therapy on sleep and mood in patients with poststroke depression: A randomized controlled trial

BACKGROUND

Poststroke depression (PSD) is one of the most common stroke complications. It not only leads to a decline in patients' quality of life but also increases the mortality of patients. In this study, the method of combining Chinese traditional exercise Baduanjin with psychotherapy was used to intervene in patients with PSD and to explore the improvement of sleep, mood, and serum levels of brain-derived neurotrophic factor (BDNF), 5-hydroxytryptamine (5-HT), and interleukin-6 (IL-6) levels in patients with PSD by combined treatment.

METHODS

A total of 100 patients with PSD who met the inclusion criteria were randomly assigned to Baduanjin group (n = 50) or control group (n = 50). The control group received treatment with escitalopram oxalate and rational emotive behavior therapy, while the experimental group received Baduanjin training in addition to the treatment given to the control group. Changes in sleep efficiency, sleep total time, sleep latency, arousal index, Hamilton Anxiety Rating Scale, Hamilton Depression Scale score, serum BDNF, 5-HT, IL-6 levels, and Modified Barthel Index were measured at baseline, 4 weeks and 8 weeks after intervention, and the results were compared between the 2 groups.

RESULTS

Significantly improvements in the sleep efficiency, sleep total time, serum 5-HT, BDNF levels, and Modified Barthel Index score were detected at week 4 in the Baduanjin group than in the control group (P < .05). Additionally, the sleep latency, arousal index, Hamilton Anxiety Rating Scale, Hamilton Depression Scale scores and IL-6 levels in the Baduanjin group were lower than those in the control group (P < .05). After 8 weeks of treatment, the above indexes in the Baduanjin group were further improved compared with the control group (P < .05), and the above indexes of the 2 groups were significantly improved compared with the baseline (P < .001).

CONCLUSION

Baduanjin exercise combined with rational emotive behavior therapy effectively improves the mood and sleep status of patients with PSD; It increases the serum levels of 5-HT and BDNF while reducing the level of serum proinflammatory factor IL-6; additionally, the intervention alleviates the degree of neurological impairment, upgrades the ability of daily living, and improves the quality of life.

MM165 - A Small Hybrid Molecule Modulates the Kynurenine Pathway and Attenuates Lipopolysaccharide-Induced Memory Deficits and Inflammation

Cognitive dysfunctions are now recognized as core symptoms of various psychiatric disorders e.g., major depressive disorder. Sustained immune activation may leads to cognitive dysfunctions. Proinflammatory cytokines shunt the metabolism of tryptophan towards kynurenine and quinolinic acid may accumulate at toxic concentrations. This acid triggers an increase in neuronal nitric oxide synthase function and promotes oxidative stress. The searching for small molecules that can regulate tryptophan metabolites produced in the kynurenic pathway has become an important goal in developing treatments for various central nervous system diseases with an inflammatory component. Previously we have identified a small hybrid molecule - MM165 which significantly reduces depressive-like symptoms caused by inflammation induced by lipopolysaccharide administration. In the present study, we investigated whether this compound would mitigate cognitive deficits induced by lipopolysaccharide administration and whether treatment with it would affect the plasma or brain levels of quinolinic acid and kynurenic acid. Neuroinflammation was induced in rats by administering lipopolysaccharide at a dose of 0.5 mg/kg body weight for 10 days. We conducted two tests: novel object recognition and object location, to assess the effect on memory impairment in animals previously treated with lipopolysaccharide. In plasma collected from rats, the concentrations of C-reactive protein and tumor necrosis factor alfa were determined. The concentrations of kynurenic acid and quinolinic acid were determined in plasma and homogenates obtained from the cerebral cortex of rats. Interleukin 6 in the cerebral cortex of rats was determined. Additionally, the body and spleen mass and spontaneous activity were measured in rats. Our study shows that MM165 may mitigate cognitive deficits induced by inflammation after administration of lipopolysaccharide and alter the concentrations of tryptophan metabolites in the brain. Compounds exhibiting a mechanism of action analogous to that of MM165 may serve as foundational structures for the development of a new class of antidepressants.

A systematic review of the association between zinc and anxiety

CONTEXT

The incidence of anxiety, which stems from both intrinsic and extrinsic factors, has been increasing worldwide. Various methods by which it can be treated or prevented have been reported thus far. One of the most popular and effective treatments is supplementation therapy. Zinc, which is an essential nutrient found in various plants, animal foods, and supplements, has been shown to be a potential nutrient in anxiety reduction by acting on γ-aminobutyric acid (GABA), glutamatergic, serotonergic, neurogenesis, and immune systems. It can also influence important receptors, such as GPR39. Thus, zinc has received considerable attention with respect to its potential role as a therapeutic or detrimental factor for anxiety; yet, the available evidence needs to be analyzed systematically to reach a convergent conclusion.

OBJECTIVE

The objective was to systematically review any potential connection between adult human anxiety and zinc intake.

DATA SOURCES AND EXTRACTION

Nine original human studies, of which 2 assessed the relationship between zinc consumption and anxiety (based on a questionnaire) and 7 assessed the relationship between serum zinc levels and anxiety, were included based on specific selection criteria. Studies that had been written in English and published in peer-reviewed publications with no restrictions on the date of publication were searched in the Google Scholar and PubMed databases. This project was also reported according to the PRISMA guidelines.

DATA ANALYSIS

As per the studies analyzed in this review, there was a noticeable relationship between serum zinc levels and anxiety, which means that patients with anxiety have lower levels of zinc in their serum, as compared with healthy individuals. Furthermore, zinc consumption was inversely associated with anxiety.

CONCLUSION

The results provide plausible evidence for the positive role of zinc in the treatment of patients afflicted with anxiety, albeit with some limitations.

Association between CNS-active drugs and risk of Alzheimer's and age-related neurodegenerative diseases

Objective

As neuropsychiatric conditions can increase the risk of age-related neurodegenerative diseases (NDDs), the impact of CNS-active drugs on the risk of developing Alzheimer's Disease (AD), non-AD dementia, Multiple Sclerosis (MS), Parkinson's Disease (PD) and Amyotrophic Lateral Sclerosis (ALS) was investigated.

Research design and methods

A retrospective cohort analysis of a medical claims dataset over a 10 year span was conducted in patients aged 60 years or older. Participants were propensity score matched for comorbidity severity and demographic parameters. Relative risk (RR) ratios and 95% confidence intervals (CI) were determined for age-related NDDs. Cumulative hazard ratios and treatment duration were determined to assess the association between CNS-active drugs and NDDs at different ages and treatment duration intervals.

Results

In 309,128 patients who met inclusion criteria, exposure to CNS-active drugs was associated with a decreased risk of AD (0.86% vs 1.73%, RR: 0.50; 95% CI: 0.47-0.53; p <.0001) and all NDDs (3.13% vs 5.76%, RR: 0.54; 95% CI: 0.53-0.56; p <.0001). Analysis of impact of drug class on risk of AD indicated that antidepressant, sedative, anticonvulsant, and stimulant medications were associated with significantly reduced risk of AD whereas atypical antipsychotics were associated with increased AD risk. The greatest risk reduction for AD and NDDs occurred in patients aged 70 years or older with a protective effect only in patients with long-term therapy (>3 years). Furthermore, responders to these therapeutics were characterized by diagnosed obesity and higher prescriptions of anti-inflammatory drugs and menopausal hormonal therapy, compared to patients with a diagnosis of AD (non-responders). Addition of a second CNS-active drug was associated with greater reduction in AD risk compared to monotherapy, with the combination of a Z-drug and an SNRI associated with greatest AD risk reduction.

Conclusion

Collectively, these findings indicate that CNS-active drugs were associated with reduced risk of developing AD and other age-related NDDs. The exception was atypical antipsychotics, which increased risk. Potential use of combination therapy with atypical antipsychotics could mitigate the risk conferred by these drugs. Evidence from these analyses advance precision prevention strategies to reduce the risk of age-related NDDs in persons with neuropsychiatric disorders.

Neuroinflammation and Post-Stroke Depression: Focus on the Microglia and Astrocytes

Post-stroke depression (PSD), a frequent and disabling complication of stroke, has a strong impact on almost thirty percent of stroke survivors. The pathogenesis of PSD is not completely clear so far. Neuroinflammation following stroke is one of underlying mechanisms that involves in the pathophysiology of PSD and plays an important function in the development of depression and is regarded as a sign of depression. During the neuroinflammation after ischemic stroke onset, both astrocytes and microglia undergo a series of morphological and functional changes and play pro-inflammatory or anti-inflammatory effect in the pathological process of stroke. Importantly, astrocytes and microglia exert dual roles in the pathological process of PSD due to the phenotypic transformation. We summarize the latest evidence of neuroinflammation involving in PSD in this review, focus on the phenotypic transformation of microglia and astrocytes following ischemic stroke and reveal the dual roles of both microglia and astrocytes in the PSD via modulating the neuroinflammation.

Lactobacillus brevis-Fermented Gamma-Aminobutyric Acid Ameliorates Depression- and Anxiety-Like Behaviors by Activating the Brain-Derived Neurotrophic Factor-Tropomyosin Receptor Kinase B Signaling Pathway in BALB/C Mice

This study investigated the effects of Lactobacillus brevis-fermented gamma-aminobutyric acid (LB-GABA) on depressive and anxiety-like behaviors with the underlying molecular mechanism in a chronic stress model of BALB/c mice. LB-GABA attenuates both neuronal cell death and the increase of monoamine oxidase activity induced by hydrogen peroxide. Behavioral tests revealed that GABA significantly increased sucrose preference and reduced immobility time in both tail suspension and forced swimming tests. LB-GABA increased exploration of the open arms in the elevated plus maze and restored activity in the open field. Moreover, LB-GABA lowered stress hormone and inflammatory mediator levels. Mechanistically, LB-GABA increased protein levels of BDNF and TrkB, activating downstream targets (AKT, ERK, and CREB), crucial for neuronal survival and plasticity. Furthermore, LB-GABA protected hippocampal neurons from stress-induced cell death and increased serotonin and dopamine levels. Overall, LB-GABA has the potential to alleviate stress-induced depression and anxiety-like symptoms and neuroinflammation by activating the BDNF-TrkB signaling pathway.

Barbaloin's Chemical Intervention in Aluminum Chloride Induced Cognitive Deficits and Changes in Rats through Modulation of Oxidative Stress, Cytokines, and BDNF Expression

Alzheimer's disease (AD) is a long-term neurodegenerative condition characterized by impaired cognitive functions, particularly in the domains of learning and memory. Finding promising options for AD can be successful with a medication repurposing strategy. The goal of the research was to examine the neuroprotective characteristics of barbaloin in aluminum chloride (AlCl3)-induced cognitive deficits and changes in rats through modulation of oxidative stress, cytokines, and brain-derived neurotrophic factor (BDNF) expression. Thirty male Wistar rats were subjected to AlCl3 at a dosage of 100 mg/kg via the per oral route (p.o.), which induced cognitive decline. Morris water maze (MWM) is used to assess behavioral metrics. Assays for catalase (CAT), malondialdehyde (MDA), reduced glutathione (GSH), acetylcholinesterase (AChE), choline-acetyltransferase (ChAT), interleukins-1β (IL-1β), superoxide dismutase (SOD), tumor necrosis factor-α (TNF-α), nuclear factor kappa-B (NF-κB), interleukins-6 (IL-6), BDNF, and neurotransmitter levels [dopamine (DA), acetylcholine (Ach), and γ-aminobutyric acid (GABA)] were performed. Results: The transfer latency time was notably decreased, and substantial modifications in the concentrations of GSH, MDA, CAT, SOD, AChE, ChAT and observed modulations in the formation of interleukins-6 (IL-6), TNF-α, IL-1β, BDNF, and NF-κB were also evidenced after the treatment of rats with barbaloin in comparison to AlCl3-induced control groups. Significant alterations in neurotransmitter levels (DA, Ach, and GABA) were also seen in barbaloin-treated groups in comparison to AlCl3-induced groups. The current investigation has provided evidence that the administration of barbaloin yielded notable enhancements in cognitive function in rats through the inhibition of MDA, enhancing endogenous antioxidant enzymes, reduction of cytokine levels, and enhancement of neurotransmitter contents in the brain. These effects were observed in comparison to a control group treated with AlCl3 and can be attributable to barbaloin's strong anti-inflammatory and antioxidant properties, and metal chelating properties may contribute to its neuroprotective effects. Barbaloin may also promote neuronal survival and enhance learning and memory by upregulating the expression of BDNF.

Antidepressant effect of Perilla frutescens essential oil through monoamine neurotransmitters and BDNF/TrkB signal pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine posits that affect-mind ill-being is the primary cause of depression, with Qi movement stagnation as its pathogenesis. As such, clinical treatment for depression should prioritize regulating Qi and relieving depressive symptoms. The pharmacological properties of traditional Chinese medicine indicate that Perilla frutescens may have potential therapeutic effects on depression and other neuropsychiatric diseases due to its ability to regulate Qi and alleviate depressive symptoms. Although previous studies have reported the antidepressant effects of Perilla frutescens, the mechanism underlying PFEO inhalation-mediated antidepressant effect remains unclear.

AIM OF THE STUDY

The aim of this investigation is to elucidate the antidepressant mechanisms of PFEO by examining its effects on monoamine neurotransmitters and the BDNF/TrkB signaling pathway.

MATERIALS AND METHODS

The CUMS rat model of depression was established, and the depressive state of the animals was assessed through sucrose preference and forced swim tests. ELISA assays were conducted to determine monoamine neurotransmitter levels in the hippocampus and cerebral cortex of rats. Immunohistochemistry, western blotting, and RT-PCR experiments were employed to investigate the BDNF/TrkB signaling pathway's regulation of depression via PFEO inhalation.

RESULTS

It has been observed that inhalation administration of PFEO can significantly enhance the preference for sugar water in CUMS rats and reduce their immobility time during forced swimming. Additionally, there was an increase in the levels of monoamine transmitters in both the hippocampus and cerebral cortex of these rats. Furthermore, there was an upregulation in the expression levels of BDNF and TrkB positive cells as well as BDNF and TrkB proteins within both regions, along with increased BDNF mRNA and TrkB mRNA expression levels.

CONCLUSION

The antidepressant effect of PFEO via inhalation administration is speculated to be mediated through the monoamine neurotransmitters and BDNF/TrkB signaling pathway.

Fasting diets: what are the impacts on eating behaviors, sleep, mood, and well-being?

Fasting diets (FDs) have drawn great attention concerning their contribution to health and disease over the last decade. Despite considerable interest in FDs, the effect of fasting diets on eating behaviors, sleep, and mood-essential components of diet satisfaction and mental health- has not been addressed comprehensively. Understanding the critical role that fasting plays in these elements will open up potential treatment avenues that have not yet been explored. The aim of the present paper was to conduct a comprehensive critical review exploring the effects of fasting on eating behaviors, sleep, and mood. There is currently a lack of clarity regarding which fasting option yields the most advantageous effects, and there is also a scarcity of consistent trials that assess the effects of FDs in a comparable manner. Similarly, the effects and/or treatment options for utilizing FDs to modify eating and sleep behaviors and enhance mood are still poorly understood. Further researches aiming at understanding the impacts of various fasting regimes, providing new insights into the gut-brain axis and offering new treatment avenues for those with resistant anxiety and depression, are warranted. Alteration of eating behaviors can have lasting effects on various physiological parameters. The use of fasting cures can underpin ancient knowledge with scientific evidence to form a new approach to the prevention and treatment of problems associated with co-morbidities or challenges pertaining to eating behaviors. Therefore, a thorough examination of the various fasting regimens and how they impact disease patterns is also warranted.

Physical Exercise as an Intervention for Depression: Evidence for Efficacy and Mu-Opioid Receptors as a Mechanism of Action

Physical exercise is often cited as an important part of an intervention for depression, and there is empirical evidence to support this. However, the mechanism of action through which any potential antidepressant effects are produced is not widely understood. Recent evidence points toward the involvement of endogenous opioids, and especially the mu-opioid system, as a partial mediator of these effects. In this chapter, we discuss the current level of empirical support for physical exercise as either an adjunctive or standalone intervention for depression. We then review the extant evidence for involvement of endogenous opioids in the proposed antidepressant effects of exercise, with a focus specifically on evidence for mu-opioid system involvement.

Different Strategies Targeting Gut Microbiota for the Management of Several Disorders: A Sustainable Approach

BACKGROUND

A potential limelight is flashed on the Gut Microbiota (GM) in the human body, which confers additional psychological as well as physiological attributes to health. Other than just occupying a wide portion of the gastrointestinal tract, it also plays numerous functions in the systems of the body. Gut Microbiota is largely responsible for a considerably vast array of conditions such as obesity, diabetes ,other metabolic disorders, and cardiovascular disorders. Strategies targeting the gut microbiota have been proposed as a promising approach for the management of these disorders.

OBJECTIVE

This review aims to summarize the different strategies targeting the gut microbiota for the management of several disorders and to highlight the importance of a sustainable approach.

METHODS

A comprehensive literature search was conducted using various databases between 2008 and 2022 that focused on the use of prebiotics, probiotics, synbiotics, postbiotics, fecal microbiota transplantation, dietary interventions, and antibiotics.

RESULTS

Different strategies targeting the gut microbiota for the management of several disorders were identified, including probiotics, prebiotics, synbiotics, postbiotics, fecal microbiota transplantation, and dietary interventions. Modification in diet and lifestyle, allowing favorable microbiota growth in the stomach, intake of prebiotics and probiotics, and fecal microbiota transplantation are amongst the widely accepted recent approaches allowing the application of GM in the field of treatment.

CONCLUSION

Although considerable steps in enhancing and understanding the mechanism of treatment with the help of gut microbiota are under progress, much diversified and elaborate research must be conducted in order to enhance and implement the use of GM with high effectiveness.

Chronic psychosocial stress triggers microglial-/macrophage-induced inflammatory responses leading to neuronal dysfunction and depressive-related behavior

Chronic environmental stress and traumatic social experiences induce maladaptive behavioral changes and is a risk factor for major depressive disorder (MDD) and various anxiety-related psychiatric disorders. Clinical studies and animal models of chronic stress have reported that symptom severity is correlated with innate immune responses and upregulation of neuroinflammatory cytokine signaling in brain areas implicated in mood regulation (mPFC; medial Prefrontal Cortex). Despite increasing evidence implicating impairments of neuroplasticity and synaptic signaling deficits into the pathophysiology of stress-related mental disorders, how microglia may modulate neuronal homeostasis in response to chronic stress has not been defined. Here, using the repeated social defeat stress (RSDS) mouse model we demonstrate that microglial-induced inflammatory responses are regulating neuronal plasticity associated with psychosocial stress. Specifically, we show that chronic stress induces a rapid activation and proliferation of microglia as well as macrophage infiltration in the mPFC, and these processes are spatially related to neuronal activation. Moreover, we report a significant association of microglial inflammatory responses with susceptibility or resilience to chronic stress. In addition, we find that exposure to chronic stress exacerbates phagocytosis of synaptic elements and deficits in neuronal plasticity. Importantly, by utilizing two different CSF1R inhibitors (the brain penetrant PLX5622 and the non-penetrant PLX73086) we highlight a crucial role for microglia (and secondarily macrophages) in catalyzing the pathological manifestations linked to psychosocial stress in the mPFC and the resulting behavioral deficits usually associated with depression.

miR-204-5p Plays a Critical Role in the Pathogenesis of Depression and Anti-depression Action of Venlafaxine in the Hippocampus of Mice

BACKGROUND

Venlafaxine has been demonstrated to treat diseases such as social anxiety disorder and depression. Most of antidepressants including venlafaxine have a certain effect, but significant side effects. Therefore, it is necessary for us to research the development of novel antidepressants for effective treatment in practice. MicroRNA-204 (miR-204) is highly expressed in brain tissue, and plays a critical role in the synaptic plasticity of hippocampal neurons in rats. However, the underlying molecular mechanism of miR-204 remains unclear to date, this study aims to offer unique insights into depression and provide a theoretical basis for clinical physicians.

METHODS

A chronic social defeat stress (CSDS) was initially adopted for establishing a mice model of depression in this research and depression-like behaviors were evaluated by a series of behavioral experiments including the sucrose preference test (SPT), the tail suspension test (TST), the forced swim test (FST) and the social interaction test (SIT). Quantitative real-time reverse transcription PCR (qRT-PCR) was also conducted to test the expression levels of miR-204 and BDNF in the hippocampus of mice. Finally, gene interference of miR-204-5p was further adopted to test whether miR-204-5p played an effective role in the antidepressant effects of venlafaxine in mice.

RESULTS

Our data implicated that CSDS significantly increased the miR-204-5p but not miR-204-3p levels in the hippocampus of mice. The treatment of venlafaxine obviously relieved depression- like behaviors of CSDS-induced mice. The usage of venlafaxine abolished the increasing effects on the expression of miR-204-5p but up-regulated the BDNF expression level in CSDS-exposured mice. More importantly, we found that genetic overexpression of miR-204-5p decreased the reverse effects of venlafaxine on depressive-like behaviors and genetic knockdown of hippocampal miR-204-5p relieved the depressive-like behaviors and neurogenesis in CSDS-induced mice.

CONCLUSION

miR-204-5p played an effective role in the antidepressant effects of venlafaxine in CSDS-induced mice.

Serotonin is a common thread linking different classes of antidepressants

Depression pathology remains elusive. The monoamine hypothesis has placed much focus on serotonin, but due to the variable clinical efficacy of monoamine reuptake inhibitors, the community is looking for alternative therapies such as ketamine (neurogenesis theory of antidepressant action). There is evidence that different classes of antidepressants may affect serotonin levels; a notion we test here. We measure hippocampal serotonin in mice with voltammetry and study the effects of acute challenges of escitalopram, fluoxetine, reboxetine, and ketamine. We find that pseudo-equivalent doses of these drugs similarly raise ambient serotonin levels, despite their differing pharmacodynamics because of differences in Uptake 1 and 2, rapid SERT trafficking, and modulation of serotonin by histamine. These antidepressants have different pharmacodynamics but have strikingly similar effects on extracellular serotonin. Our findings suggest that serotonin is a common thread that links clinically effective antidepressants, synergizing different theories of depression (synaptic plasticity, neurogenesis, and the monoamine hypothesis).

Preventive effect of peptides derived from fermented milk on chronic stress-induced brain damage and intestinal dysfunction in mice

This study investigated the preventive effects of peptides derived from milk fermented with the probiotic strain Lactobacillus gasseri 505 (505) against stress-related brain damage and anxiety-like behavior. The peptides MKPWIQPKTKVIPYVRYL (Pep14) and VYQHQKAMKPWIQPKTKVIPYVRYL (Pep21), which exhibit high antioxidant and anti-inflammatory activities, were administered to stressed mice. The results showed that the stress mechanism in the gut-brain axis was regulated by pretreatment with both peptides, leading to inhibition of neurodevelopment and neuroinflammation through the hypothalamic-pituitary-adrenal (HPA) axis, based on the expression of related mRNA and proteins. The expression of colonic inflammation-related mRNA and proteins was also reduced. Moreover, anxiety-like behavior was significantly reduced in mice treated with Pep14 and Pep21. These results indicate that the bioactive peptides Pep14 and Pep21, derived from milk fermented with 505, may prevent stress-induced brain damage and anxiety-like behavior via regulation of the HPA axis.

Alterations of learning and memory are accompanied by alterations in the expression of 5-HT receptors, glucocorticoid receptor and brain-derived neurotrophic factor in different brain regions of an animal model of depression generated by neonatally male treatment with clomipramine in male rats

Depressive illness has been associated with impaired cognitive processes accompanied by reduced neurotrophin levels, especially brain-derived neurotrophic factor (BDNF), and dysfunctions in the hypothalamic-pituitary-adrenal (HPA) axis. In addition, depression is characterized by a decreased functioning of the serotonergic system due to changes in the activity or expression of its receptors including, most significantly, 5-HT1A, 5-HT2A, and 5-HT3 in brain regions that regulate mood, emotions, and memory, such as the prefrontal cortex, hippocampus, and amygdala. In this regard, rats treated with clomipramine (CMI) in the neonatal stage show depression-like behaviors that persist into adulthood; hence, this constitutes an adequate model of depression for exploring various molecular aspects associated with the etiology of this disorder. This, study, then, was designed to analyze the long-term effects of early postnatal exposure to CMI on the expression of 5-HT1A, 5-HT2A, and 5-HT3 receptors, as well as BDNF and GR in the following brain regions: PFC, amygdala, hippocampus, and hypothalamus, which could be related to alterations in memory and learning, as evaluated using the novel object recognition (NOR) and Morris water maze (MWM). Expression of the 5-HT1A, 5-HT2A, and 5-HT3 receptors, BDNF, and the glucocorticoid receptor (GR) was assessed by RT-qPCR in the four aforementioned brain regions, all of which play important roles in the control of memory and mood. Findings show that neonatal treatment with CMI causes alterations in memory and learning, as indicated by alterations in the results of the MWM and NOR tests. Expression of the 5-HT1A receptor increased in the hippocampus, amygdala, and hypothalamus, but decreased in the PFC, while the 5-HT2A and BDNF receptors decreased their expression in the PFC, amygdala, and hippocampus. There was no change in the expression of the 5-HT3 receptor. In addition, expression of GR in the hippocampus and PFC was low, but increased in the hypothalamus. Taken together, these data show that neonatal CMI treatment produces permanent molecular changes in brain regions related to learning and memory that could contribute to explaining the behavioral alterations observed in this model.

Nickel and aluminium mixture elicit memory impairment by activation of oxidative stress, COX-2, and diminution of AChE, BDNF and NGF levels in cerebral cortex and hippocampus of male albino rats

This study evaluated nickel and aluminium-induced neurotoxicity, as a binary metal mixture. Twenty-eight male Sprague Dawley albino rats were weight-matched and divided into four groups. Group 1 (control) received deionized water. Group 2 and 3 received Aluminium (1 mg/kg) and Nickel (0.2 mg/kg) respectively, while Group 4 received Ni and Al mixture HMM three times a week orally for 90 days. Barnes maze tests was performed. Rats were sacrificed under pentobarbital anaesthesia, cerebral cortex and hippocampus were separated, and metal levels were measured using Atomic Absorption Spectroscopy (AAS). Malondialdehyde (MDA), catalase (CAT), glutathione content (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), Brain Derived Neurotrophic Factor (BDNF), Nerve growth factor NGF, cyclo-oxygenase COX-2 and Acetylcholinesterase (AChE) were assayed using ELISA kits. Ni/Al binary mixture exposed rats showed a shorter latency period (though not significant) of 3.21 ± 1.40 s in comparison to 3.77 ± 1.11 (Ni only) and 3.99 ± 1.16(Al only). Ni/Al mixture gp had the lowest levels of Mg in both the hippocampus and frontal cortex when compared with the individual metals. In the hippocampus Al only exposed rats significantly showed p < 0.05 higher iron and Ca levels in comparison to Ni/Al mixture. Al alone significantly showed p < 0.05 lower levels of Fe but higher Ca than the Ni/Al mixture group. Exposure to Al only showed lower levels of BDNF in comparison to Ni/Al combination, whereas Ni/Al mixture gp had lower levels of NGF in comparison to the individual metals in the hippocampus. In the frontal cortex Ni only, group showed significantly lower BDNF in comparison to Ni/Al mixture whereas the mixture showed significantly lower NGF when compared with Al only group. There were higher levels of COX-2 in the Ni/Al mixture than individual metal treated rats in both hippocampus and frontal cortex. AChE levels in the Ni/Al mixture group was higher than Ni or Al only gps in the hippocampus whereas in the frontal cortex, Ni/Al exposed rats showed significantly lower AChE levels in comparison to Al only group. Ni, Al and Ni/Al mixture exhibited memory impairment by activation of oxidative stress, COX-2, and diminution of AChE, BDNF and NGF levels in cerebral cortex and hippocampus. The BDNF-COX-2 AChE signalling pathway may be involved in the neurotoxicity of Ni and Al.

Antidepressants escitalopram and venlafaxine up-regulate BDNF promoter IV but down-regulate neurite outgrowth in differentiating SH-SY5Y neurons

Antidepressants are used to treat depression and some anxiety disorders, including use in pregnant patients. The pharmacological actions of these drugs generally determine the uptake and metabolism of a series of neurotransmitters, such as serotonin, norepinephrine, or dopamine, along with an increase in BDNF expression. However, many aspects of antidepressant action remain unknown, particularly whether antidepressants interfere with normal neurodevelopment when taken by pregnant women. In order to reveal cellular and molecular implications crucial to the functioning of pathways related to antidepressant effects, we performed an investigation on neuronally differentiating human SH-SY5Y cells. To our knowledge, this is the first time human SH-SY5Y cells in cultures of purely neuronal cells induced by controlled differentiation with retinoic acid are followed by short-term 48-h exposure to 0.1-10 μM escitalopram or venlafaxine. Treatment with antidepressants (1 μM) did not affect the electrophysiological properties of SH-SY5Y cells. However, the percentage of mature neurons exhibiting voltage-gated sodium currents was substantially higher in cultures pre-treated with either antidepressant. After exposure to escitalopram or venlafaxine, we observed a concentration-dependent increase in activity-dependent BDNF promoter IV activation. The assessment of neurite metrics showed significant down-regulation of neurite outgrowth upon exposure to venlafaxine. Identified changes may represent links to molecular processes of importance to depression and be involved in neurodevelopmental alterations observed in postpartum children exposed to antidepressants antenatally.

Circulating short chain fatty acids and fatigue in patients with head and neck cancer: A longitudinal prospective study

Fatigue among patients with head and neck cancer (HNC) has been associated with higher inflammation. Short-chain fatty acids (SCFAs) have been shown to have anti-inflammatory and immunoregulatory effects. Therefore, this study aimed to examine the association between SCFAs and fatigue among patients with HNC undergoing treatment with radiotherapy with or without concurrent chemotherapy. Plasma SCFAs and the Multidimensional Fatigue Inventory-20 were collected prior to and one month after the completion of treatment in 59 HNC patients. The genome-wide gene expression profile was obtained from blood leukocytes prior to treatment. Lower butyrate concentrations were significantly associated with higher fatigue (p = 0.013) independent of time of assessment, controlling for covariates. A similar relationship was observed for iso/valerate (p = 0.025). Comparison of gene expression in individuals with the top and bottom 33% of butyrate or iso/valerate concentrations prior to radiotherapy revealed 1,088 and 881 significantly differentially expressed genes, respectively (raw p < 0.05). The top 10 Gene Ontology terms from the enrichment analyses revealed the involvement of pathways related to cytokines and lipid and fatty acid biosynthesis. These findings suggest that SCFAs may regulate inflammatory and immunometabolic responses and, thereby, reduce inflammatory-related symptoms, such as fatigue.

Cefaclor causes vagus nerve-mediated depression-like symptoms with gut dysbiosis in mice

Antibiotics are increasingly recognized as causing neuropsychiatric side effects including depression and anxiety. Alterations in central serotonin and 5-HT receptor expression are implicated in the pathogenesis of anxiety and depression, which are highly comorbid with gastrointestinal disorders. Nevertheless, it is still unclear how antibiotics can cause anxiety and depression. In this study, oral administration of cefaclor, a second-generation cephalosporin antibiotic, induced anxiety- and depression-like behaviors and colitis with gut microbiota alteration in mice. Cefaclor reduced serotonin levels and fluctuated 5-HT receptor mRNA expressions such as Htr1a, Htr1b, and Htr6 in the hippocampus. Vagotomy attenuated the cefaclor-induced anxiety- and depression-like symptoms, while the cefaclor-induced changes in gut bacteria alteration and colitis were not affected. Fluoxetine attenuated cefaclor-induced anxiety- and depression-like behaviors. Furthermore, fluoxetine decreased cefaclor-resistant Enterobacteriaceae and Enterococcaceae. Taken together, our findings suggest that the use of antibiotics, particularly, cefaclor may cause gut dysbiosis-dependent anxiety and depression through the microbiota-gut-blood-brain and microbiota-gut-vagus nerve-brain pathway. Targeting antibiotics-resistant pathogenic bacteria may be a promising therapeutic strategy for the treatment of anxiety and depression.

Examining Associations Between Women's Mental Health and Obesity

Obesity is a common comorbidity associated with mental illness. It is important to understand the many ways weight gain and obesity can impact the cause and course of mental illness in women, with a special focus on vulnerable life stages. Women seem disproportionally impacted by the weight gain side effects of medications, and issues such as weight gain are more likely to impact symptoms of mental illness, impacting self-esteem. This article summarizes the existing literature on the associations between women's mental health and obesity. Understanding this association will lead to better health outcomes.

BDNF Unveiled: Exploring Its Role in Major Depression Disorder Serotonergic Imbalance and Associated Stress Conditions

Brain-derived neurotrophic factor (BDNF) is a neurotrophin that plays a significant role in the survival and development of neurons, being involved in several diseases such as Alzheimer's disease and major depression disorder. The association between BDNF and major depressive disorder is the subject of extensive research. Indeed, numerous studies indicate that decreased levels of BDNF are linked to an increased occurrence of depressive symptoms, neuronal loss, and cortical atrophy. Moreover, it has been observed that antidepressive therapy can help restore BDNF levels. In this review, we will focus on the role of BDNF in major depression disorder serotonergic imbalance and associated stress conditions, particularly hypothalamic-pituitary-adrenal (HPA) axis dysregulation and oxidative stress. All of these features are highly connected to BDNF signaling pathways in the context of this disease, and exploring this topic will aim to advance our understanding of the disorder, improve diagnostic and treatment approaches, and potentially identify new therapeutic targets to alleviate the heavy burden of depression on society.

Patient-derived Enterococcus mundtii and its capsular polysaccharides cause depression through the downregulation of NF-κB-involved serotonin and BDNF expression

The genus Enterococcus is commonly overpopulated in patients with depression compared to healthy control in the feces. Therefore, we isolated Enterococcus faecalis, Enterococcus durans, Enterococcus gallinarum, Enterococcus faecium, and Enterococcus mundtii from the feces of patients with comorbid inflammatory bowel disease with depression and examined their roles in depression in vivo and in vitro. Of these Enterococci, E. mundtii NK1516 most potently induced NF-κB-activated TNF-α and IL-6 expression in BV2 microglia cells. NK1516 also caused the most potent depression-like behaviors in the absence of sickness behaviors, neuroinflammation, downregulated brain-derived neurotrophic factor (BDNF), and serotonin (5-HT) levels in the hippocampus of mice. Furthermore, E. mundtii NK1516 reduced the mRNA expression of Htr1a in the hippocampus. Its capsular polysaccharide (CP), but not cytoplasmic components, also caused depression-like behaviors and reduced BDNF and serotonin levels in the hippocampus. Conversely, this was not observed with E. mundtii ATCC882, a well-known probiotic, or its CP. Orally gavaged fluorescence isothiocyanate (FITC)-conjugated NK1516 CP was detected in the hippocampus of mice. The NK1516 genome exhibited unique CP biosynthesis-related genes (capD, wbjC, WecB, vioB), unlike that of ATCC882. These findings suggest that E. mundtii may be a risk factor for depression.

Postpartum depression: aetiology, pathogenesis and the role of nutrients and dietary supplements in prevention and management

Postpartum depression (PPD) is a challenging psychological disorder faced by 10-30% of mothers across the globe. In India, it occurs among 22% of mothers. Its aetiology and pathophysiology aren't fully understood as of today but multiple theories on the interplay of hormones, neurotransmitters, genetics, epigenetics, nutrients, socio-environmental factors, etc. exist. Nutrients are not only essential for the synthesis of neurotransmitters, but they may also indirectly influence genomic pathways that methylate DNA, and there is evidence for molecular associations between nutritional quality and psychological well-being. Increased behavioural disorders have been attributed to macro- and micronutrient deficiencies, and dietary supplementation has been effective in treating several neuropsychiatric illnesses. Nutritional deficiencies occur frequently in women, especially during pregnancy and breastfeeding. The aim of this study was to perform a comprehensive literature review of evidence-based research in order to identify, gather and summarize existing knowledge on PPD's aetiology, pathophysiology, and the role of nutrients in its prevention as well as management. The possible mechanisms of action of nutrients are also presented here. Study findings show that the risk of depression increases when omega-3 fatty acid levels are low. Both fish oil and folic acid supplements have been used to effectively treat depression. Antidepressant efficacy is lowered by folate insufficiency. Folate, vitamin B12, iron, etc. deficiencies are more prevalent in depressed people than in non-depressed people. Serum cholesterol levels and plasma tryptophan levels are found to be inversely correlated with PPD. Serum vitamin D levels were associated inversely with perinatal depression. These findings highlight the importance of adequate nutrition in the antepartum period. Given that nutritional therapies can be affordable, safe, simple to use, and are typically well-accepted by patients, more focus should be placed on dietary variables in PPD.

Long-Term Soft-Food Rearing in Young Mice Alters Brain Function and Mood-Related Behavior

The relationship between caloric and nutrient intake and overall health has been extensively studied. However, little research has focused on the impact of the hardness of staple foods on health. In this study, we investigated the effects of a soft diet on brain function and behavior in mice from an early age. Mice fed a soft diet for six months exhibited increased body weight and total cholesterol levels, along with impaired cognitive and motor function, heightened nocturnal activity, and increased aggression. Interestingly, when these mice were switched back to a solid diet for three months, their weight gain ceased, total cholesterol levels stabilized, cognitive function improved, and aggression decreased, while their nocturnal activity remained high. These findings suggest that long-term consumption of a soft diet during early development can influence various behaviors associated with anxiety and mood regulation, including weight gain, cognitive decline, impaired motor coordination, increased nocturnal activity, and heightened aggression. Therefore, the hardness of food can impact brain function, mental well-being, and motor skills during the developmental stage. Early consumption of hard foods may be crucial for promoting and maintaining healthy brain function.

Regulation of Satiety by Bdnf-e2-Expressing Neurons through TrkB Activation in Ventromedial Hypothalamus

The transcripts for Bdnf (brain-derived neurotrophic factor), driven by different promoters, are expressed in different brain regions to control different body functions. Specific promoter(s) that regulates energy balance remain unclear. We show that disruption of Bdnf promoters I and II but not IV and VI in mice (Bdnf-e1^-/-, Bdnf-e2^-/-) results in obesity. Whereas Bdnf-e1^-/- exhibited impaired thermogenesis, Bdnf-e2^-/- showed hyperphagia and reduced satiety before the onset of obesity. The Bdnf-e2 transcripts were primarily expressed in ventromedial hypothalamus (VMH), a nucleus known to regulate satiety. Re-expressing Bdnf-e2 transcript in VMH or chemogenetic activation of VMH neurons rescued the hyperphagia and obesity of Bdnf-e2^-/- mice. Deletion of BDNF receptor TrkB in VMH neurons in wildtype mice resulted in hyperphagia and obesity, and infusion of TrkB agonistic antibody into VMH of Bdnf-e2^-/- mice alleviated these phenotypes. Thus, Bdnf-e2-transcripts in VMH neurons play a key role in regulating energy intake and satiety through TrkB pathway.

Memory impairments in rodent depression models: A link with depression theories

More than 80% of depressed patients struggle with learning new tasks, remembering positive events, or concentrating on a single topic. These neurocognitive deficits accompanying depression may be linked to functional and structural changes in the prefrontal cortex and hippocampus. However, their mechanisms are not yet completely understood. We conducted a narrative review of articles regarding animal studies to assess the state of knowledge. First, we argue the contribution of changes in neurotransmitters and hormone levels in the pathomechanism of cognitive dysfunction in animal depression models. Then, we used numerous neuroinflammation studies to explore its possible implication in cognitive decline. Encouragingly, we also observed a positive correlation between increased oxidative stress and a depressive-like state with concomitant memory deficits. Finally, we discuss the undeniable role of neurotrophin deficits in developing cognitive decline in animal models of depression. This review reveals the complexity of depression-related memory impairments and highlights the potential clinical importance of gathered findings for developing more reliable animal models and designing novel antidepressants with procognitive properties.

Exploring the Therapeutic Effect of Neurotrophins and Neuropeptides in Neurodegenerative Diseases: at a Glance

Neurotrophins and neuropeptides are the essential regulators of peripheral nociceptive nerves that help to induce, sensitize, and maintain pain. Neuropeptide has a neuroprotective impact as it increases trophic support, regulates calcium homeostasis, and reduces excitotoxicity and neuroinflammation. In contrast, neurotrophins target neurons afflicted by ischemia, epilepsy, depression, and eating disorders, among other neuropsychiatric conditions. Neurotrophins are reported to inhibit neuronal death. Strategies maintained for "brain-derived neurotrophic factor (BDNF) therapies" are to upregulate BDNF levels using the delivery of protein and genes or compounds that target BDNF production and boosting BDNF signals by expanding with BDNF mimetics. This review discusses the mechanisms of neurotrophins and neuropeptides against acute neural damage as well as highlighting neuropeptides as a potential therapeutic agent against Parkinson's disease (PD), Huntington's disease (HD), Alzheimer's disease (AD), and Machado-Joseph disease (MJD), the signaling pathways affected by neurotrophins and their receptors in both standard and diseased CNS systems, and future perspectives that can lead to the potent application of neurotrophins and neuropeptides in neurodegenerative diseases (NDs).