Neurotrophic factors and neuroplasticity pathways in the pathophysiology and treatment of depression

Psilocybin promotes neuroplasticity and induces rapid and sustained antidepressant-like effects in mice

BACKGROUND

Psilocybin offers new hope for treating mood disorders due to its rapid and sustained antidepressant effects, as standard medications require weeks or months to exert their effects. However, the mechanisms underlying this action of psilocybin have not been identified.

AIMS

To investigate whether psilocybin has rapid and sustained antidepressant-like effects in mice and investigate whether its potential mechanisms of action are related to promoted neuroplasticity.

METHODS

We first examined the antidepressant-like effects of psilocybin in normal mice by the forced swimming test and in chronic corticosterone (CORT)-exposed mice by the sucrose preference test and novelty-suppressed feeding test. Furthermore, to explore the role of neuroplasticity in mediating the antidepressant-like effects of psilocybin, we measured structural neuroplasticity and neuroplasticity-associated protein levels in the prefrontal cortex (PFC) and hippocampus.

RESULTS

We observed that a single dose of psilocybin had rapid and sustained antidepressant-like effects in both healthy mice and chronic CORT-exposed mice. Moreover, psilocybin ameliorated chronic CORT exposure-induced inhibition of neuroplasticity in the PFC and hippocampus, including by increasing neuroplasticity (total number of dendritic branches and dendritic spine density), synaptic protein (p-GluA1, PSD95 and synapsin-1) levels, BDNF-mTOR signalling pathway activation (BDNF, TrkB and mTOR levels), and promoting neurogenesis (number of DCX-positive cells).

CONCLUSIONS

Our results demonstrate that psilocybin elicits robust, rapid and sustained antidepressant-like effects which is accompanied by the promotion of neuroplasticity in the PFC and hippocampus.

Effects of antidepressant and antipsychotic medication on peripheral brain-derived neurotrophic factor concentration: Systematic review and meta-analysis

Brain-derived neurotrophic factor (BDNF) is an important regulatory protein in the pathophysiology of psychiatric disorders. Several studies have reported the relationship between peripheral BDNF concentrations and the use of psychoactive drugs. However, the results remain controversial. This study aimed to evaluate the effects of psychoactive drugs on BDNF concentrations and to explore the association between changes in BDNF concentrations and improvements in clinical scores. A systematic review and meta-analysis were conducted. Six electronic databases, including PubMed, Scopus, Medline, Web of Science, Google Scholar and Science Direct, were searched. Changes in BDNF concentrations were compared before and after psychoactive treatment, using the standardized mean difference (SMD) and 95 % confidence interval (95 % CI). Twenty-three studies were included. A significant increase in serum BDNF concentrations was observed after treatment with antipsychotics (SMD=0.43; 95 %CI: 0.26, 0.60) and antidepressants (SMD=0.49; 95 %CI: 0.23, 0.74). However, the plasma BDNF concentration was not affected by antidepressant and antipsychotic medication. Although an improvement in clinical scores was observed after treatment, no significant association was observed between changes in BDNF concentrations and the changes in the Positive and Negative Syndrome Scale (PANSS) and the Hamilton Depression Rating Scale (HAM-D) scores. In conclusion, antidepressants and antipsychotics increase serum BDNF concentrations.

A potential research target for cardiac rehabilitation: brain-derived neurotrophic factor

Cardiovascular diseases pose a major threat to human life, functional activity, and quality of life. Once the disease is present, patients can experience varying degrees of problems or limitations on three levels: physical, psychological, and social. Patients with cardiovascular disease are always at risk for adverse cardiac events, decreased physical activity, psychoemotional disturbances, and limited social participation due to their varying pathologies. Therefore, personalized cardiac rehabilitation is of great significance in improving patients' physical and mental functions, controlling disease progression, and preventing deterioration. There is a consensus on the benefits of cardiac rehabilitation in improving patients' quality of life, enhancing functional activity, and reducing mortality. As an important part of cardiac rehabilitation, Exercise plays an irreplaceable role. Aerobic exercise, resistance training, flexibility training, and other forms of exercise are recommended by many experts. Improvements in exercise tolerance, lipid metabolism, cardiac function, and psychological aspects of the patients were evident with appropriate exercise interventions based on a comprehensive assessment. Further studies have found that brain-derived neurotrophic factor may be an important mediator of exercise's ability to improve cardiovascular health. Brain-derived neurotrophic factor exerts multiple biological effects on the cardiovascular system. This article provides another perspective on the cardiac effects of exercise and further looks at the prospects for the use of brain-derived neurotrophic factor in cardiac rehabilitation. Meanwhile, the new idea that brain-derived neurotrophic factor is a key mediator connecting the brain-cardiac axis is proposed in light of the current research progress, to provide new ideas for clinical rehabilitation and scientific research.

Tremendous Fidelity of Vitamin D3 in Age-related Neurological Disorders

Vitamin D3 (VD) is a secosteroid hormone and shows a pleiotropic effect in brain-related disorders where it regulates redox imbalance, inflammation, apoptosis, energy production, and growth factor synthesis. Vitamin D3's active metabolic form, 1,25-dihydroxy Vitamin D3 (1,25(OH)2D3 or calcitriol), is a known regulator of several genes involved in neuroplasticity, neuroprotection, neurotropism, and neuroinflammation. Multiple studies suggest that VD deficiency can be proposed as a risk factor for the development of several age-related neurological disorders. The evidence for low serum levels of 25-hydroxy Vitamin D3 (25(OH)D3 or calcidiol), the major circulating form of VD, is associated with an increased risk of Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), dementia, and cognitive impairment. Despite decades of evidence on low VD association with neurological disorders, the precise molecular mechanism behind its beneficial effect remains controversial. Here, we will be delving into the neurobiological importance of VD and discuss its benefits in different neuropsychiatric disorders. The focus will be on AD, PD, and HD as they share some common clinical, pathological, and epidemiological features. The central focus will be on the different attributes of VD in the aspect of its anti-oxidative, anti-inflammatory, anti-apoptotic, anti-cholinesterase activity, and psychotropic effect in different neurodegenerative diseases.

Treatment of Depression with Acupuncture Based on Pathophysiological Mechanism

Depression is a prevalent mental disorder and has a profound impact on an individual's psychological and physical well-being. It is characterized by a persistently depressed mood, loss of interest, energy loss, and cognitive dysfunction. In recent years, more and more people have changed to mental diseases, such as depression, anxiety, mania and so on. In the incidence of depression, covering all ages, but still mainly young and middle-aged women. Traditional treatments for depression mainly rely on medication and psychotherapy, but these methods are not effective for all patients and are often accompanied by certain side effects. Therefore, finding safe and effective alternative or adjuvant treatments has become a priority. Here we highlight the research progress of acupuncture in the treatment of depression and to explore the mechanism of acupuncture in the treatment of depression. Acupuncture treatment of depression is an ancient and effective method, the mechanism involves multiple biological pathways, for example, by regulating neurotransmitter levels, regulating the neuroendocrine axis, improving neuroplasticity, anti-inflammatory and other effects, improving emotional state and play an antidepressant role. To provide evidence to support the widespread use of acupuncture in clinical practice. We hope to provide new treatment ideas and methods for patients with depression, and even reduce the incidence of depression.

Research on the mechanism of antidepressive effect of Suanzaoren Decoction through TLR4/MyD88/NF-κB pathway and Wnt/β-catenin pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Increased inflammatory response and disruption of neuroplasticity are important mechanisms in the hypothesis of the pathogenesis of depression. Thus, these two aspects are conducive to the development of treatments for depression. Suanzaoren Decoction (SZRD) is a classic traditional Chinese medicine compound for the treatment of insomnia, which can clinically relieve depression symptoms, but its antidepressant pharmacological mechanism remains to be elucidated.

AIM OF THIS STUDY

Based on the hypothesis of inflammation and neuroplasticity in depression, this study aimed to investigate the antidepressant effect of SZRD and its specific molecular mechanism through chronic unpredictable mild stress (CUMS) induced SD rat model and lipopolysaccharide (LPS) induced BV2 cell neuroinflammation model.

MATERIALS AND METHODS

The body weight and behavioral indexes of CUMS model rats treated with orally or without oral SZRD for 4 weeks were detected. Hematoxylin and eosin staining was used to observe brain pathological damage. Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling (TUNEL) staining was used to observe neuronal apoptosis. Immunofluorescence, ELISA kit and Western blotting were used to detect the inflammatory index Iba-1 and inflammatory factors, as well as the important inflammatory pathway TLR4/MyD88/NF-κB. Enzyme linked immunosorbent assay (ELISA) and western blotting were used to detect neuroplasticity indexes proteins-brain-derived neurotrophic factor (BDNF), presynaptic membrane protein-synaptophysin (SYP), and postsynaptic protein- 95(PSD95), and the key pathway Wnt/β-catenin. The possible mechanism of SZRD antidepressant was further explored in LPS-induced BV2 cells.

RESULTS

In vivo and in vitro experiments showed that SZRD treatment significantly reversed the depression-like behaviors in rats, decreased the levels of inflammatory factors and increased the expression levels of BDNF, SYP, PSD95 in depression model rats. Furthermore, SZRD treatment inhibited the activation of TLR4/MyD88/NF-κB and Wnt/β-catenin pathways and reduced the massive nuclear translocation of NF-κB and β-catenin. The addition of NF-κB pathway agonists could partially offset the inhibitory effect of SZRD on the Wnt pathway, and the addition of Wnt pathway agonists could also partially offset the inhibitory effect of SZRD on the TLR4 pathway.

CONCLUSION

This study suggestted that SZRD may exert its antidepressant effect by regulating TLR4/MyD88/NF-κB pathway and Wnt/β-catenin pathway in combination.

Effect of Transcranial Direct Current Stimulation (tDCS) on Depression in Parkinson's Disease-A Narrative Review

INTRODUCTION

Depression is the most prevalent comorbid neuropsychiatric condition in individuals with Parkinson's disease (PD), and its underlying mechanisms are not yet fully understood. Current treatment methods are characterised by moderate effectiveness and possible side effects, prompting the search for new non-invasive and safe treatment methods.

METHODS

This narrative review explores the use of transcranial direct current stimulation (tDCS) in the treatment of depression in PD, based on neuropsychological measures. Searches were conducted in the PubMed/Medline, Research Gate, and Cochrane databases.

RESULTS

Nine relevant studies were identified, where depression scores served as either primary or secondary outcomes. Stimulation protocols displayed heterogeneity, especially concerning choice of stimulation site. Patient samples were also heterogeneous. The majority of the studies incorporated anodal stimulation targeting the left dorsolateral prefrontal cortex (DLPFC). The results revealed a reduction in depression scores among PD patients following tDCS. Potential mechanisms through which tDCS may alleviate depression in PD were discussed and recommendations for future research were made.

CONCLUSIONS

Preliminary evidence suggests that tDCS applied anodally to the left DLPFC reduces depression scores in people with PD; however, due to the heterogeneity of the studies analysed, the use of tDCS in this field should be approached with caution and warrants further validation and confirmation.

Serum levels of interleukin-33 and mesencephalic astrocyte derived neurotrophic factors in patients with major depressive disorder: a cross-sectional comparative design

BACKGROUND

Major depressive disorder (MDD) is a debilitating health condition that has significant morbidity and mortality rates. Depression can be caused due to social, biological, environmental, psychological, and genetic factors. A few biological processes have been proposed as the pathophysiological pathways of depression. Neurotrophic factors and inflammatory cytokines have been linked to depression. Thus, we aimed to investigate the serum interleukin-33 (IL-33) and mesencephalic astrocyte-derived neurotrophic factor (MANF) in MDD patients and corresponding healthy controls (HCs).

METHOD

This study involved the inclusion of 129 MDD patients and 125 HCs matched by sex and age. A psychiatrist evaluated the study participants following DSM-5 criteria. The severity of the illness was assessed utilizing the Hamilton Depression Rating Scale (Ham-D). The serum concentrations of IL-33 and MANF were measured using enzyme-linked immunosorbent assay (ELISA) kits.

RESULTS

The mean serum levels of IL-33 were decreased (159.12 ± 6.07 pg/ml vs. 180.60 ± 8.64 pg/ml, p = 0.042), and the MANF levels were increased (5.40 ± 0.19 ng/ml vs. 4.46 ± 0.21 ng/ml, p = 0.001) in MDD patients when compared to HCs.

CONCLUSIONS

The current study proposes that lower IL-33 and higher MANF serum levels are associated with MDD progression and depression severity. These biomarkers could be used as risk assessment tools for MDD. We recommend more investigation, including a significant population, to determine the precise function of IL-33 and MANF in depression.

Altered in vivo early neurogenesis traits in patients with depression: Evidence from neuron-derived extracellular vesicles and electroconvulsive therapy

BACKGROUND

The neurogenesis hypothesis is a promising candidate etiologic hypothesis for depression, and it is associated with electroconvulsive therapy (ECT). However, human in vivo molecular-level evidence is lacking.

OBJECTIVE

We used neuron-derived extracellular vesicles (NDEVs) as a "window to the neurons" to explore the in vivo neurogenesis status associated with ECT in patients with treatment-resistant depression (TRD).

METHODS

In this study, we enrolled 40 patients with TRD and 35 healthy controls (HCs). We isolated NDEVs from the plasma of each participant to test the levels of doublecortin (DCX), a marker of neurogenesis, and cluster of differentiation (CD) 81, a marker of EVs. We also assessed the plasma levels of brain-derived neurotrophic factor (BDNF), a protein that is known to be associated with ECT and neuroplastic processes.

RESULTS

Our findings indicated that both the levels of DCX in NDEVs and BDNF in plasma were significantly lower in TRD patients compared to HCs at baseline, but increased following ECTs. Conversely, levels of CD81 in NDEVs were found higher in TRD patients at baseline, but did not change after the ECT treatments. Exploratory analyses revealed that lower levels of BDNF in plasma and DCX in NDEVs, along with higher CD81 levels in NDEVs, were associated with more severe depressive symptoms and reduced cognitive function at baseline. Furthermore, higher baseline CD81 concentrations in NDEVs were correlated with greater decreases in depression symptoms.

CONCLUSIONS

We first present human in vivo evidence of early neurogenesis using DCX through NDEVs: decreased in TRD patients, increased after ECTs.

Potential molecular pathways of angiotensin receptor blockers in the brain toward cognitive improvement in dementia

The alarming rise of cognitive impairment and memory decline and limited effective solutions present a worldwide concern for dementia patients. The multivariant role of the renin-angiotensin system (RAS) in the brain offers strong evidence of a role for angiotensin receptor blockers (ARBs) in the management of memory impairment by modifying glutamate excitotoxicity, downregulating inflammatory cytokines such as interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)α, inhibiting kynurenine aminotransferase (KAT)-II, nucleotide-binding domain, leucine-rich-containing family and pyrin-domain-containing-3 (NLRP3) inflammasomes, boosting cholinergic activity, activating peroxisome proliferator-activated receptor (PPAR)-γ, countering cyclooxygenase (COX) and mitigating the hypoxic condition. The present work focuses on the intricate molecular mechanisms involved in brain-RAS, highlighting the role of ARBs, connecting links between evidence-based unexplored pathways and investigating probable biomarkers involved in dementia through supported preclinical and clinical literature.

Current genetic data on depression and anxiety in Parkinson's disease patients

Parkinson's disease (PD) is a common neurodegenerative disorder affecting about 1 % of the population over the age of 60 years. PD is characterized by a wide spectrum of symptomatology including not only motor symptoms but non-motor symptoms, as well. Depression is one of the most common non-motor manifestations, and the most frequent neuropsychiatric comorbidity in PD. Neuropsychiatric symptoms like depression and anxiety may precede the appearance of motor features, highlighting their importance in the early detection of the disease and its strategic management. This review discusses the possible genetic background of the development of these neuropsychiatric symptoms in PD patients analyzing current genetic data associated with this clinical entity.

β-glucan, a specific immuno-stimulant, produces rapid antidepressant effects by stimulating ERK1/2-dependent synthesis of BDNF in the hippocampus

A decline in microglia in the dentate gyrus of the hippocampus has recently been described as an important mechanism for the progression of depression. Reversal of this decline by innate immune system stimulants may represent a novel strategy to ameliorate the depressive phenotype in chronically stressed animals. β-glucan is a polysaccharide from Saccharomyces cerevisiae. It can efficiently stimulate microglia without inducing the production of pro-inflammatory cytokines. Therefore, β-glucan could be an ideal drug to ameliorate depressive phenotypes. In the present study, we found that a single injection of β-glucan reversed depression-like behaviors in mice induced by chronic unpredictable stress (CUS) in a dose-dependent manner, which was accompanied by a reversal of the CUS-induced decrease in brain-derived neurotrophic factor (BDNF) protein levels in the dentate gyrus. The crucial role of BDNF signaling in the antidepressant effect of β-glucan was demonstrated by experiments showing that infusion of an anti-BDNF antibody into dentate gyrus, construction of BDNF-Val68Met allele knock-in mice, or treatment with the BDNF receptor antagonist K252a abolished the antidepressant effect of β-glucan. The increased BDNF signaling induced by β-glucan was mediated by extracellular signal-regulated kinase1/2 (ERK1/2)-mediated BDNF synthesis, and inhibition of ERK1/2 by SL327 was able to abolish the antidepressant effect of β-glucan. Moreover, inhibition or depletion of microglia by minocycline or PLX3397 abolished the reversal effect of β-glucan on CUS-induced depression-like behaviors and CUS-induced impairment of ERK1/2-BDNF signaling. These results suggest that β-glucan exhibits antidepressant effects by stimulating microglia-mediated activation of ERK1/2 and synthesis of BDNF in the hippocampus.

The Impact of UFP-512 in Mice with Osteoarthritis Pain: The Role of Hydrogen Sulfide

The pain-relieving properties of opioids in inflammatory and neuropathic pain are heightened by hydrogen sulfide (H2S). However, whether allodynia and functional and/or emotional impairments related to osteoarthritis (OA) could be reduced by activating δ-opioid receptors (DOR) and the plausible influence of H2S on these actions has not been completely established. In female C57BL/6J mice with OA pain generated via monosodium acetate (MIA), we analyze: (i) the effects of UFP-512 (a DOR agonist), given alone and co-administered with two H2S donors, on the symptoms of allodynia, loss of grip strength (GS), and anxiodepressive-like comportment; (ii) the reversion of UFP-512 actions with naltrindole (a DOR antagonist), and (iii) the impact of UFP-512 on the expression of phosphorylated NF-kB inhibitor alpha (p-IKBα) and the antioxidant enzymes superoxide dismutase 1 (SOD-1) and glutathione sulfur transferase M1 (GSTM1); and the effects of H2S on DOR levels in the dorsal root ganglia (DRG), amygdala (AMG), and hippocampus (HIP) of MIA-injected animals. Results showed that systemic and local administration of UFP-512 dose-dependently diminished the allodynia and loss of GS caused by MIA, whose effects were potentiated by H2S and reversed by naltrindole. UFP-512 also inhibited anxiodepressive-like behaviors, normalized the overexpression of p-IKBα in DRG and HIP, and enhanced the expression of SOD-1 and GSTM1 in DRG, HIP, and/or AMG. Moreover, the increased expression of DOR triggered by H2S might support the improved analgesic actions of UFP-512 co-administered with H2S donors. This study proposes the use of DOR agonists, alone or combined with H2S donors, as a new treatment for OA pain.

The Role of BDNF and NPY Levels, Effects of Behavioral Systems and Emotion Regulation on Internet Addiction in Adolescents

Internet addiction (IA), one of the behavioral addictions, is also related to impulsivity. Although studies on its etiology and risks continue, the number of studies is limited. In this study, we aimed to assess the roles of behavioral systems, emotional regulation (ER), and impulsivity in the development of IA in adolescents and also to assess the relationship between all these clinical parameters and brain-derived neurotrophic factor (BDNF) and neuropeptide Y (NPY). Forty-two adolescents with IA and 30 healthy controls (ages 12 -17) were included in the study. Self-reported measures included the Internet Addiction Scale. (IAS), Behavioral Activation and Behavioral Inhibition Scale (BAS/BIS), Barratt. Impulsiveness Scale-11 (BIS-11), and Difficulties in Emotion Regulation Scale-16 (DERS-16) were used for the assessment of the participants. The levels of plasma brain BDNF and NPY were evaluated with the ELISA method. BAS/BIS subscale scores, BIS-11, and DERS-16 scale total scores were found to be statistically significantly higher, while BDNF and NPY levels were found to be lower in adolescents with IA compared to the healthy controls. IA severity was not found to correlate with both BDNF and NPY. IA was found to be more related to BIS than to BAS. There is a need for further studies evaluating developmental features and possible diagnostic biomarkers that may be associated with IA in adolescents.

Environmental Enrichment Rescues Oxidative Stress and Behavioral Impairments Induced by Maternal Care Deprivation: Sex- and Developmental-Dependent Differences

Stress is related to major depressive disorder (MDD). This study investigated the action that early stress, represented by maternal deprivation (MD), has on the behavior and oxidative stress of Wistar female and male rats. Also, it was evaluated whether changes induced by MD could be reversed by environmental enrichment (EE). Male and female rats were divided into a non-MD and MD group. The MD group was subdivided into 3 groups: (1) assessed on the 31st day after exposure to EE for 10 days, (2) assessed on the 41st day after exposure to EE for 20 days, and (3) assessed on the 61st day after exposure to EE for 40 days. Behavioral tests were performed (memory habituation and elevated plus maze). Oxidative stress parameters were evaluated peripherally. MD was able to promote anxiety-like behavior at postnatal day (PND) 41 and impair memory at PND 31 and PND 61 in male and PND 41 and PND 61 in female rats. MD was associated with increased oxidative stress parameters (reactive species to thiobarbituric acid levels (TBARS), carbonylated proteins, nitrite/nitrate concentration), and altered antioxidant defenses (superoxide dismutase (SOD) and catalase (CAT), and sulfhydryl content) in different stages of development. The EE was able to reverse almost all behavioral and biochemical changes induced by MD; however, EE effects were sex and developmental period dependent. These findings reinforce the understanding of the gender variable as a biological factor in MDD related to MD and EE could be considered a treatment option for MDD treatment and its comorbidities.

Metformin Improves Comorbid Depressive Symptoms in Mice with Allergic Rhinitis by Reducing Olfactory Bulb Damage

Allergic rhinitis (AR) is a widespread disease that is frequently comorbid with depression. However, the mechanisms and treatments for depression in AR remain underexplored. Metformin, a widely used antidiabetic drug, has shown antidepressant effects. The aim of this study was to explore the effects and potential mechanisms of metformin on depression-like behaviors in an AR mouse model. In the present study, mice were sensitized and challenged with ovalbumin (OVA) to induce AR. Results showed that mice with AR exhibited significant depression-like behavior which was attenuated by metformin. In addition, the levels of expression of synaptic plasticity markers (anti-microtubule-associated protein 2, synaptophysin, postsynaptic density protein 95), neurogenesis markers (doublecortin and Ki-67), and brain-derived neurotrophic factor were decreased in the olfactory bulb (OB) of mice with AR, while metformin ameliorated all these alterations and reduced apoptosis in the OB of these mice. Furthermore, it enhanced the phosphorylation of AMP-activated kinase (AMPK) and the levels of ten-eleven translocation 2 (TET2) and 5-hydroxymethylcytosine in the OB. In conclusion, our findings suggest that metformin might be a viable strategy for treating AR-related depression, possibly by modulating neuroplasticity, neurogenesis, apoptosis, and BDNF signaling in the OB via the AMPK/TET2 pathway.

OPRM1 and BDNF polymorphisms associated with a compensatory neurophysiologic signature in knee osteoarthritis patients

OBJECTIVE

The present study investigated the relationship between three genetic polymorphisms of OPRM1 (rs1799971 - A118G and rs1799972 - C17T) and BDNF (rs6265 - C196T) and EEG-measured brain oscillations in Knee Osteoarthritis (KOA) patients.

MATERIALS AND METHODS

We performed a cross-sectional analysis of a cohort study (DEFINE cohort), KOA arm, with 66 patients, considering demographic (age, sex, and education), clinical (pain intensity and duration), OPRM1 (rs1799971 - A118G and rs1799972 - C17T) and BDNF (rs6265 - C196T) genotypes, and electrophysiological measures. Brain oscillations relative power from Delta, Theta, Alpha, Low Alpha, High Alpha, Beta, Low Beta and High Beta oscillations were measured during resting state EEG. Multivariate regression models were used to explore the main brain oscillation predictors of the three genetic polymorphisms.

RESULTS

Our findings demonstrate that Theta and Low Beta oscillations are associated with the variant allele of OPRM1-rs1799971 (A118G) on left frontal and left central regions, respectively, while Alpha brain oscillation is associated with variant genotypes (CT/TT) of BDNF-rs6265 on frontal (decrease of oscillation power) and left central (increase of oscillation power) regions. No significant model was found for OPRM1-rs1799972 (C17T) in addition to the inclusion of pain intensity as a significant predictor of this last model.

CONCLUSION

One potential interpretation for these findings is that polymorphisms of OPRM1 - that is involved with endogenous pain control - lead to increased compensatory oscillatory mechanisms, characterized by increased theta oscillations. Along the same line, polymorphisms of the BDNF lead to decreased alpha oscillations in the frontal area, likely also reflecting the disruption of resting states to also compensate for the increased injury associated with knee OA. It is possible that these polymorphisms require additional brain adaption to the knee OA related injury.

The beneficial effects of vortioxetine on BDNF, CREB, S100B, β amyloid, and glutamate NR2b receptors in chronic unpredictable mild stress model of depression

BACKGROUND

Depression, one of the most significant mental disorders, is still poorly understood in terms of its pathogenetic mechanisms despite its well-recognized association with stress.

OBJECTIVES

The current study's goal was to ascertain how the novel antidepressant drug vortioxetine (VOR) affected the BDNF (brain-derived neurotrophic factor), S100, amyloid β (Aβ), CREB (cAMP response element-binding protein), and NR2B, as well as its impact on depression-like behaviors, and tissue damage in an experimental rodent model of depression caused by chronic unpredictable stress.

METHODS

We employed twenty-eight Wistar albino male rats, and we randomly divided them into four groups, each consisting of 7 rats: control, CUMS (chronic unpredictable mild stress), CUMS+vortioxetine (CUMS+VOR), and CUMS+fluoxetine (CUMS+FLU). Sucrose preference and forced swimming tests (SPT and FST, respectively), PCR, ELISA, and histopathological and immunohistochemical evaluation were made on brains.

RESULTS

The behaviors of reduced immobility in the FST and increased sucrose preference were observed in the CUMS group and they improved in the groups treated with VOR and FLU. Compared with the control group, the group exposed to CUMS showed increased Aβ and decreased BDNF, CREB, and S-100 expressions, as well as neuronal degeneration (p<0.001). VOR and FLU treatment ameliorate the findings.

CONCLUSIONS

This study demonstrated significant ameliorative effects of VOR in an experimental model of chronic unpredictable depression to reduce brain tissue damage and depression-like behaviors in rats. Effects of CUMS on the brain and possible effects of VOR.

Neuropsychological Effects of Antidepressants: Translational Studies

Pharmacological treatments that improve mood were first identified serendipitously, but more than half a century later, how these drugs induce their antidepressant effects remains largely unknown. With the help of animal models, a detailed understanding of their pharmacological targets and acute and chronic effects on brain chemistry and neuronal function has been achieved, but it remains to be elucidated how these effects translate to clinical efficacy. Whilst the field has been dominated by the monoamine and neurotrophic hypotheses, the idea that the maladaptive cognitive process plays a critical role in the development and perpetuation of mood disorders has been discussed since the 1950s. Recently, studies using objective methods to quantify changes in emotional processing found acute effects with conventional antidepressants in both healthy volunteers and patients. These positive effects on emotional processing and cognition occur without a change in the subjective ratings of mood. Building from these studies, behavioural methods for animals that quantify similar cognitive affective processes have been developed. Integrating these behavioural approaches with pharmacology and targeted brain manipulations, a picture is beginning to emerge of the underlying mechanisms that may link the pharmacology of antidepressants, these neuropsychological constructs and clinical efficacy. In this chapter, we discuss findings from animal studies, experimental medicine and patients investigating the neuropsychological effects of antidepressant drugs. We discuss the possible neural circuits that contribute to these effects and discuss whether a neuropsychological model of antidepressant effects could explain the temporal differences in clinical benefits observed with conventional delayed-onset antidepressants versus rapid-acting antidepressants.

Verbascoside: A neuroprotective phenylethanoid glycosides with anti-depressive properties

BACKGROUND

Verbascoside is a natural and water-soluble phenylethanoid glycoside found in several medicinal plants. It has extensive pharmacological effects, including antioxidative and antineoplastic actions, and a wide range of therapeutic effects against depression.

PURPOSE

In this review, we appraised preclinical and limited clinical evidence to fully discuss the anti-depression capacity of verbascoside and its holistic characteristics that can contribute to better management of depression in vivo and in vitro models, as well as, its toxicities and medicinal value.

METHODS

This review was prepared according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). A systematic review of 32 preclinical trials published up to April 2023, combined with a comprehensive bioinformatics analysis of network pharmacology and molecular docking, was conducted to elucidate the antidepressant mechanism of action of verbascoside. Studies included in the systematic review were obtained from 7 electronic databases: PubMed, Scopus, Web of Science, Cochrane, ResearchGate, ScienceDirect, and Google Scholar.

RESULTS

Studies on the antidepressant effects of verbascoside showed that various pharmacological mechanisms and pathways, such as modulating the levels of monoamine neurotransmitters, inhibiting hypothalamic-pituitary-adrenal (HPA) axis hyperfunction and promoting neuroprotection may be involved in the process of its action against depression. Verbascoside promotes dopamine (DA) biosynthesis by promoting the expression of tyrosine hydroxylase mRNA and protein, upregulates the expression of 5-hydroxytryptamine receptor 1B (5-HT1B), prominence protein, microtubule-associated protein 2 (MAP2), hemeoxygenase-1 (HO-1), SQSTM1, Recombinant Autophagy Related Protein 5 (ATG5) and Beclin-1, and decreases the expression of caspase-3 and a-synuclein, thus exerting antidepressant effects. We identified seven targets (CCL2, FOS, GABARAPL1, CA9, TYR, CA12, and SQSTM1) and three signaling pathways (glutathione metabolism, metabolism of xenobiotics by cytochrome P450, fluid shear stress and atherosclerosis) as potential molecular biological sites for verbascoside.

CONCLUSIONS

These findings provide strong evidence that verbascoside exerts its antidepressant effects through various pharmacological mechanisms. However, further multicentre clinical case-control and molecularly targeted fishing studies are required to confirm the clinical efficacy of verbascoside and its underlying direct targets.

Pathogenesis and treatment of depression: Role of diet in prevention and therapy

In recent years, there has been a significant increase in depression, which is related to, among other things, the COVID-19 pandemic. Depression can be fatal if not treated or if treated inappropriately. Depression is the leading cause of suicide attempts. The disease is multifactorial, and pharmacotherapy often fails to bring satisfactory results. Therefore, increasingly more importance is attached to the natural healing substances and nutrients in food, which can significantly affect the therapy process and prevention of depressive disorders. A proper diet is vital to preventing depression and can be a valuable addition to psychological and pharmacologic treatment. An inadequate diet may reduce the effectiveness of antidepressants or increase their side effects, leading to life-threatening symptoms. This study aimed to review the literature on the pathogenesis of the development and treatment of depression, with particular emphasis on dietary supplements and the role of nutrition in the prevention and treatment of depressive disorders.

Antidepressant-like effects of the Punica granatum and citalopram combination are associated with structural changes in dendritic spines of granule cells in the dentate gyrus of rats

Introduction: Natural products such as phytoestrogens-enriched foods or supplements have been considered as an alternative therapy to reduce depressive symptoms associated with menopause. It is known that the aqueous extract of Punica granatum (AE-PG) exerts antidepressant-like effects by activating β-estrogen receptors and facilitates the antidepressant response of the clinical drug citalopram (CIT). However, the effects on neuroplasticity are unknown. Objectvie investigated the antidepressant-like response of combining AE-PG and CIT at sub-optimal doses, analyzing their effects on the formation and maturation of dendrite spines in granule cells as well as on the dendrite complexity. Methods: Ovariectomized Wistar rats (3-month-old) were randomly assigned to one of the following groups: A) control (saline solution as vehicle of CIT and AE-PG, B) AE-PG at a sub-threshold dose (vehicle of CIT plus AE-PG at 0.125 mg/kg), C) CIT at a sub-threshold dose (0.77 mg/kg plus vehicle of AE-PG), and D) a combination of CIT plus AE-PG (0.125 mg/kg and 0.77 mg/kg, respectively). All rats were treated intraperitoneally for 14 days. Antidepressant-like effects were evaluated using the force swimming test test (FST). The complexity of dendrites and the number and morphology of dendrite spines of neurons were assessed in the dentate gyrus after Golgi-Cox impregnation. The expressions of the mature brain-derived neurotrophic factor (mBDNF) in plasma and of mBDNF and synaptophysin in the hippocampus, as markers of synaptogenesis, were also determined. Results: Administration of CIT combined with AE-PG, but not alone, induced a significant antidepressant-like effect in the FST with an increase in the dendritic complexity and the number of dendritic spines in the dentate gyrus (DG) of the hippocampus, revealed by the thin and stubby categories of neurons at the granular cell layer. At the same time, an increase of mBDNF and synaptophysin expression was observed in the hippocampus of rats that received the combination of AE-PG and CIT.

The antidepressant-like effects of Danzhi Xiaoyao San and its active ingredients

BACKGROUND

Depression is a severe mental illness that endangers human health. Depressed individuals are prone to sleep less and to the loss of appetite for food; their thinking and cognition processes, as well as mood, may even be affected. Danzhi Xiaoyao San (DXS), documented in the Internal Medicine Summary, has been used for hundreds of years in China and is widely applied traditionally to treat liver qi stagnation, liver and spleen blood deficiency, menstrual disorders, and spontaneous and night sweating. DXS can also clear heat and drain the liver. Presently, it is used frequently in the treatment of depression based on its ability to clear the liver and alleviate depression.

PURPOSE

To summarize clinical and preclinical studies on the antidepressant-like effects of DXS, understand the material basis and mechanisms of these effects, and offer new suggestions and methods for the clinical treatment of depression.

METHODS

"Danzhi Xiaoyao", "Danzhixiaoyao", "Xiaoyao", "depression" and active ingredients were entered as keywords in PubMed, Google Scholar, CNKI and WANFANG DATA databases in the search for material on DXS and its active ingredients. The PRISMA guidelines were followed in this review process.

RESULTS

Per clinical reports, DXS has a therapeutic effect on patients with depression but few side effects. DXS and its active ingredients allegedly produce their neuroprotective antidepressant-like effects by modulating monoamine neurotransmitter levels, inhibiting the hypothalamic-pituitary-adrenal (HPA) axis hyperfunction, reducing neuroinflammation and increasing neurotrophic factors.

CONCLUSION

Overall, DXS influences multiple potential mechanisms to exert its antidepressant-like effects thanks to its multicomponent character. Because depression is not caused by a single mechanism, probing the antidepressant-like effects of DXS could further help understand the pathogenesis of depression and discover new antidepressant drugs.

Prokineticin System Is a Pharmacological Target to Counteract Pain and Its Comorbid Mood Alterations in an Osteoarthritis Murine Model

Osteoarthritis (OA) is the most prevalent joint disease associated with chronic pain. OA pain is often accompanied by mood disorders. We addressed the role of the Prokineticin (PK) system in pain and mood alterations in a mice OA model induced with monosodium iodoacetate (MIA). The effect of a PK antagonist (PC1) was compared to that of diclofenac. C57BL/6J male mice injected with MIA in the knee joint were characterized by allodynia, motor deficits, and fatigue. Twenty-eight days after MIA, in the knee joint, we measured high mRNA of PK2 and its receptor PKR1, pro-inflammatory cytokines, and MMP13. At the same time, in the sciatic nerve and spinal cord, we found increased levels of PK2, PKR1, IL-1β, and IL-6. These changes were in the presence of high GFAP and CD11b mRNA in the sciatic nerve and GFAP in the spinal cord. OA mice were also characterized by anxiety, depression, and neuroinflammation in the prefrontal cortex and hippocampus. In both stations, we found increased pro-inflammatory cytokines. In addition, PK upregulation and reactive astrogliosis in the hippocampus and microglia reactivity in the prefrontal cortex were detected. PC1 reduced joint inflammation and neuroinflammation in PNS and CNS and counteracted OA pain and emotional disturbances.

Modulation of neurotrophic factors in the treatment of dementia, stroke and TBI: Effects of Cerebrolysin

Neurotrophic factors (NTFs) are involved in the pathophysiology of neurological disorders such as dementia, stroke and traumatic brain injury (TBI), and constitute molecular targets of high interest for the therapy of these pathologies. In this review we provide an overview of current knowledge of the definition, discovery and mode of action of five NTFs, nerve growth factor, insulin-like growth factor 1, brain derived NTF, vascular endothelial growth factor and tumor necrosis factor alpha; as well as on their contribution to brain pathology and potential therapeutic use in dementia, stroke and TBI. Within the concept of NTFs in the treatment of these pathologies, we also review the neuropeptide preparation Cerebrolysin, which has been shown to resemble the activities of NTFs and to modulate the expression level of endogenous NTFs. Cerebrolysin has demonstrated beneficial treatment capabilities in vitro and in clinical studies, which are discussed within the context of the biochemistry of NTFs. The review focuses on the interactions of different NTFs, rather than addressing a single NTF, by outlining their signaling network and by reviewing their effect on clinical outcome in prevalent brain pathologies. The effects of the interactions of these NTFs and Cerebrolysin on neuroplasticity, neurogenesis, angiogenesis and inflammation, and their relevance for the treatment of dementia, stroke and TBI are summarized.

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.

Gypenoside-14 Reduces Depression via Downregulation of the Nuclear Factor Kappa B (NF-kB) Signaling Pathway on the Lipopolysaccharide (LPS)-Induced Depression Model

Neuroinflammation is a common pathogenetic sign of depression and is closely linked to the development of depression. Many clinical anti-inflammatory drugs act as antidepressants by reducing the neuroinflammatory response. Previous research found that gypenosides and their bioactive compound gypenoside-14 (GP-14) had neuroprotective effects against hypoxia-induced injury and reduced neuroinflammation-related high-altitude cerebral edema. Here we investigated the effects of GP-14 on the lipopolysaccharide (LPS)-induced depression-like behavior model. LPS (0.5 mg/kg) was injected into mice intraperitoneally for 7 consecutive days to induce depression-like behavior, which is considered a model for the exacerbation of depression. GP-14 in the amount of 100 mg/kg was simultaneously administered by gavage for 7 days. In the LPS-induced depression model, GP-14 not only attenuated depression-like behavior but also improved the anxiety-like behavior of the mice. Additionally, GP-14 treatment mitigated learning and cognitive decline in depressed mice. ELISA and immunofluorescence staining results revealed that GP-14 inhibited the upregulation of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), and suppressed the activation of astrocytes induced with LPS, indicating its potent anti-inflammatory effect. GP-14 pretreatment in C8 cells and primary astrocytes can inhibit the activation of the NF-κB signaling pathway and downregulate the levels of pro-inflammatory factors. In summary, our findings showed that GP-14 had significant anti-inflammation and anti-depression properties; thus, GP-14 could be a promising lead compound for treating depression.

Oral calcium and vitamin D supplements differentially alter exploratory, anxiety-like behaviors and memory in male rats

Oral calcium and calcium plus vitamin D supplements are commonly prescribed to several groups of patients, e.g., osteoporosis, fracture, and calcium deficiency. Adequate and steady extracellular calcium levels are essential for neuronal activity, whereas certain forms of calcium supplement (e.g., CaCO3) probably interfere with memory function. However, it was unclear whether a long-term use of ionized calcium (calcium chloride in drinking water ad libitum), vitamin D supplement (oral gavage) or the combination of both affected anxiety and memory, the latter of which was probably dependent on the hippocampal neurogenesis. Here, we aimed to determine the effects of calcium and/or vitamin D supplement on the anxiety- and memory-related behaviors and the expression of doublecortin (DCX), an indirect proxy indicator of hippocampal neurogenesis. Eight-week-old male Wistar rats were divided into 4 groups, i.e., control, calcium chloride-, 400 UI/kg vitamin D3-, and calcium chloride plus vitamin D-treated groups. After 4 weeks of treatment, anxiety-, exploration- and recognition memory-related behaviors were evaluated by elevated pulse-maze (EPM), open field test (OFT), and novel object recognition (NOR), respectively. The hippocampi were investigated for the expression of DCX protein by Western blot analysis. We found that oral calcium supplement increased exploratory behavior as evaluated by OFT and the recognition index in NOR test without any effect on anxiety behavior in EPM. On the other hand, vitamin D supplement was found to reduce anxiety-like behaviors. Significant upregulation of DCX protein expression was observed in the hippocampus of both calcium- and vitamin D-treated rats, suggesting their positive effects on neurogenesis. In conclusion, oral calcium and vitamin D supplements positively affected exploratory, anxiety-like behaviors and/or memory in male rats. Thus, they potentially benefit on mood and memory in osteoporotic patients beyond bone metabolism.

Variation of Circulating Brain-Derived Neurotrophic Factor (BDNF) in Depression: Relationships with Inflammatory Indices, Metabolic Status and Patients' Clinical Features

This study seeks to offer a contribution to the method of subtyping major depressed patients by exploring the possible relationships between circulating brain-derived neurotrophic factor (BDNF), different peripheral inflammatory/metabolic markers in the blood and clinical characteristics. Thirty-nine patients, thoroughly diagnosed according to the DSM-5 criteria, underwent a comprehensive set of evaluations encompassing structured interviews, rating scales and a panel of blood tests. Correlation and comparison analyses were carried out by means of non-parametric statistical tests. Concurrently, a principal component analysis was performed to explain biochemical variance. The findings of our research unveiled that leukocyte counts, their ratios and other inflammatory parameters are positively correlated with depression scores. Moreover, we found variations within the BDNF pools of depressed patients. Specifically, higher levels of platelet-poor plasma BDNF (PPP-BDNF) were correlated with augmented inflammatory markers in patients showing specific episode characteristics, whereas reduced platelet BDNF (PLT-BDNF) provided a better indication of the changes that were linked to a diagnosis of long-term depression. Our findings suggest that PPP-BDNF and PLT-BDNF might differentiate depression conditions. They also imply usefulness in appraising peripheral biomarker profiles in patients for a deeper characterization of major depressive episodes. At the same time, it is plausible that they might constitute novel avenues for developing more tailored therapeutic strategies for patients with MDs.

Depression among Patients with an Implanted Left Ventricular Assist Device: Uncovering Pathophysiological Mechanisms and Implications for Patient Care

Depression is a common and devastating mental illness associated with increased morbidity and mortality, partially due to elevated rates of suicidal attempts and death. Select patients with end-stage heart failure on a waiting-list for a donor heart undergo left ventricular assist device (LVAD) implantation. The LVAD provides a circulatory flow of oxygenated blood to the body, mimicking heart functionality by operating on a mechanical technique. LVAD improves functional capacity and survivability among patients with end-stage heart failure. However, accumulating data suggests that LVAD recipients suffer from an increased incidence of depression and suicide attempts. There is scarce knowledge regarding the pathological mechanism and appropriate treatment approach for depressed LVAD patients. This article summarizes the current evidence on the association between LVAD implantation and occurrence of depression, suggesting possible pathological mechanisms underlying the device-associated depression and reviewing the current treatment strategies. The summarized data underscores the need for a rigorous pre-(LVAD)-implantation psychiatric evaluation, continued post-implantation mental health assessment, and administration of antidepressant treatment as necessary.

Correlation of brain-derived neurotrophic factor with severity of depression and treatment response

Background

Brain-derived neurotrophic factor (BDNF) is a modulator of neuroplasticity in the brain. It plays an important role in the pathophysiology of depression through the stress pathway. The information about correlation of BDNF levels with depression severity and treatment response in Indian population is scarce.

Methods

Consecutive 60 never treated cases with depression reporting to a large tertiary care psychiatry unit and 60 healthy matched controls from 01 January 2016 to 31 December 2016 were enrolled for study. Sociodemographic data were collected. Diagnosis of depression was carried out as per International Classification of Diseases-10th revision (ICD-10) diagnostic criteria for research. The Hamilton Rating Scale for Depression (HRSD) was administered and accordingly scored. Venous blood for BDNF levels was collected from all cases and controls. Cases were reassessed after 04 weeks of treatment with HRSD and BDNF levels.

Results

The mean level of serum BDNF among cases (18.56 ng/ml) was found to be reduced significantly as compared with healthy controls (32.41 ng/ml). The mean serum BDNF level (18.56 ng/ml) in never treated cases was significantly negatively correlated with the median clinical HRSD score (18.5). There was a significant increase in the mean level of serum BDNF after antidepressant treatment.

Conclusion

The study has revealed statistically significant low levels of serum BDNF in cases not exposed to treatment with depression compared with healthy controls. There was significant negative correlation of levels of serum BDNF with depression severity. The levels of serum BDNF significantly increased after four weeks of treatment.

Exploratory genome-wide analyses of cortical inhibition, facilitation, and plasticity in late-life depression

Late-life depression (LLD) is a heterogenous mood disorder influenced by genetic factors. Cortical physiological processes such as cortical inhibition, facilitation, and plasticity may be markers of illness that are more strongly associated with genetic factors than the clinical phenotype. Thus, exploring the relationship between genetic factors and these physiological processes may help to characterize the biological mechanisms underlying LLD and improve diagnosis and treatment selection. Transcranial magnetic stimulation (TMS) combined with electromyography was used to measure short interval intracortical inhibition (SICI), cortical silent period (CSP), intracortical facilitation (ICF), and paired associative stimulation (PAS) in 79 participants with LLD. We used exploratory genome-wide association and gene-based analyses to assess for genetic correlations of these TMS measures. MARK4 (which encodes microtubule affinity-regulating kinase 4) and PPP1R37 (which encodes protein phosphatase 1 regulatory subunit 37) showed genome-wide significant association with SICI. EGFLAM (which encodes EGF-like fibronectin type III and laminin G domain) showed genome-wide significant association with CSP. No genes met genome-wide significant association with ICF or PAS. We observed genetic influences on cortical inhibition in older adults with LLD. Replication with larger sample sizes, exploration of clinical phenotype subgroups, and functional analysis of relevant genotypes is warranted to better characterize genetic influences on cortical physiology in LLD. This work is needed to determine whether cortical inhibition may serve as a biomarker to improve diagnostic precision and guide treatment selection in LLD.

Towards Novel Potential Molecular Targets for Antidepressant and Antipsychotic Pharmacotherapies

Depression and schizophrenia are two highly prevalent and severely debilitating neuropsychiatric disorders. Both conventional antidepressant and antipsychotic pharmacotherapies are often inefficient clinically, causing multiple side effects and serious patient compliance problems. Collectively, this calls for the development of novel drug targets for treating depressed and schizophrenic patients. Here, we discuss recent translational advances, research tools and approaches, aiming to facilitate innovative drug discovery in this field. Providing a comprehensive overview of current antidepressants and antipsychotic drugs, we also outline potential novel molecular targets for treating depression and schizophrenia. We also critically evaluate multiple translational challenges and summarize various open questions, in order to foster further integrative cross-discipline research into antidepressant and antipsychotic drug development.

Short-Term Irisin Treatment Enhanced Neurotrophin Expression Differently in the Hippocampus and the Prefrontal Cortex of Young Mice

As a result of physical exercise, muscle releases multiple exerkines, such as "irisin", which is thought to induce pro-cognitive and antidepressant effects. We recently demonstrated in young healthy mice the mitigation of depressive behaviors induced by consecutive 5 day irisin administration. To understand which molecular mechanisms might be involved in such effect, we here studied, in a group of mice previously submitted to a behavioral test of depression, the gene expression of neurotrophins and cytokines in the hippocampus and prefrontal cortex (PFC), two brain areas frequently investigated in the depression pathogenesis. We found significantly increased mRNA levels of nerve growth factor (NGF) and fibroblast growth factor 2 (FGF-2) in the hippocampus and brain-derived growth factor (BDNF) in the PFC. We did not detect a difference in the mRNA levels of interleukin 6 (IL-6) and IL-1β in both brain regions. Except for BDNF in the PFC, two-way ANOVA analysis did not reveal sex differences in the expression of the tested genes. Overall, our data evidenced a site-specific cerebral modulation of neurotrophins induced by irisin treatment in the hippocampus and the PFC, contributing to the search for new antidepressant treatments targeted at single depressive events with short-term protocols.

Designing multi-target drugs for the treatment of major depressive disorder

INTRODUCTION

Major depressive disorders (MDD) pose major health burdens globally. Currently available medications have their limitations due to serious adverse effects, long latency periods as well as resistance. Considering the highly complicated pathological nature of this disorder, it has been suggested that multitarget drugs or multi-target-directed ligands (MTDLs) may provide long-term therapeutic solutions for the treatment of MDD.

AREAS COVERED

In the current review, recent lead design and lead modification strategies have been covered. Important investigations reported in the last ten years (2013-2022) for the pre-clinical development of MTDLs (through synthetic medicinal chemistry and biological evaluation) for the treatment of MDD were discussed as case studies to focus on the recent design strategies. The discussions are categorized based on the pharmacological targets. On the basis of these important case studies, the challenges involved in different design strategies were discussed in detail.

EXPERT OPINION

Even though large variations were observed in the selection of pharmacological targets, some potential biological targets (NMDA, melatonin receptors) are required to be explored extensively for the design of MTDLs. Similarly, apart from structure activity relationship (SAR), in silico techniques such as multitasking cheminformatic modelling, molecular dynamics simulation and virtual screening should be exploited to a greater extent.

Serum BDNF levels are involved in the diagnosis and treatment response in patients with PD

BACKGROUND

The study aimed to explore whether brain-derived neurotrophic factor (BDNF) could be predictive for the diagnosis of panic disorder (PD) and to explore the association between serum BDNF levels and the treatment response to escitalopram in PD patients.

METHODS

Ninety PD patients and 99 healthy controls (HCs) were finally recruited. PD patients were treated only by escitalopram for 8 weeks. All patients were administered the Short-Form Health Survey-36 (SF-36), Hamilton Anxiety Rating Scale (HAMA-14), and State-Trait Anxiety Inventory (STAI) to assess life quality, anxiety symptoms and trait, respectively. Neuropsychological tests were assessed at baseline in all participants. Besides, peripheral venous blood was drawn from all participants for BDNF serum levels detection both at baseline and after 8 weeks of treatment.

RESULTS

In PD patients, the baseline serum BDNF levels were lower than HCs. The area under the ROC curve (AUC) of baseline serum BDNF levels predicting PD from HCs was 0.947 (94.9 % for sensitivity, 77.8 % for specificity). The baseline serum BDNF levels (beta = 0.276, p = 0.007), the current duration (beta = -0.301, p = 0.004), and trait anxiety (TAI) (beta = 0.201, p = 0.045) were predictors for reduction rates of HAMA-14 after 8 weeks' escitalopram treatment.

LIMITATIONS

A long-term observation and high homogeneity of sample may make the results more convincing.

CONCLUSION

This preliminary finding highlighted the value of serum BDNF levels for the diagnosis of PD. In addition, the higher baseline serum BDNF levels may predict the better escitalopram treatment response in PD patients.

Sarcopenia and Cognitive Decline in Older Adults: Targeting the Muscle-Brain Axis

Declines in physical performance and cognition are commonly observed in older adults. The geroscience paradigm posits that a set of processes and pathways shared among age-associated conditions may also serve as a molecular explanation for the complex pathophysiology of physical frailty, sarcopenia, and cognitive decline. Mitochondrial dysfunction, inflammation, metabolic alterations, declines in cellular stemness, and altered intracellular signaling have been observed in muscle aging. Neurological factors have also been included among the determinants of sarcopenia. Neuromuscular junctions (NMJs) are synapses bridging nervous and skeletal muscle systems with a relevant role in age-related musculoskeletal derangement. Patterns of circulating metabolic and neurotrophic factors have been associated with physical frailty and sarcopenia. These factors are mostly related to disarrangements in protein-to-energy conversion as well as reduced calorie and protein intake to sustain muscle mass. A link between sarcopenia and cognitive decline in older adults has also been described with a possible role for muscle-derived mediators (i.e., myokines) in mediating muscle-brain crosstalk. Herein, we discuss the main molecular mechanisms and factors involved in the muscle-brain axis and their possible implication in cognitive decline in older adults. An overview of current behavioral strategies that allegedly act on the muscle-brain axis is also provided.

The Role of BDNF as a Biomarker in Cognitive and Sensory Neurodegeneration

Brain-derived neurotrophic factor (BDNF) has a crucial function in the central nervous system and in sensory structures including olfactory and auditory systems. Many studies have highlighted the protective effects of BDNF in the brain, showing how it can promote neuronal growth and survival and modulate synaptic plasticity. On the other hand, conflicting data about BDNF expression and functions in the cochlear and in olfactory structures have been reported. Several clinical and experimental research studies showed alterations in BDNF levels in neurodegenerative diseases affecting the central and peripheral nervous system, suggesting that BDNF can be a promising biomarker in most neurodegenerative conditions, including Alzheimer's disease, shearing loss, or olfactory impairment. Here, we summarize current research concerning BDNF functions in brain and in sensory domains (olfaction and hearing), focusing on the effects of the BDNF/TrkB signalling pathway activation in both physiological and pathological conditions. Finally, we review significant studies highlighting the possibility to target BDNF as a biomarker in early diagnosis of sensory and cognitive neurodegeneration, opening new opportunities to develop effective therapeutic strategies aimed to counteract neurodegeneration.

Challenging the Pleiotropic Effects of Repetitive Transcranial Magnetic Stimulation in Geriatric Depression: A Multimodal Case Series Study

BACKGROUND

Although the antidepressant potential of repetitive transcranial magnetic stimulation (rTMS), the pleiotropic effects in geriatric depression (GD) are poorly investigated. We tested rTMS on depression, cognitive performance, growth/neurotrophic factors, cerebral blood flow (CBF) to transcranial Doppler sonography (TCD), and motor-evoked potentials (MEPs) to TMS in GD.

METHODS

In this case series study, six drug-resistant subjects (median age 68.0 years) underwent MEPs at baseline and after 3 weeks of 10 Hz rTMS on the left dorsolateral prefrontal cortex. The percentage change of serum nerve growth factor, vascular endothelial growth factor, brain-derived growth factor, insulin-like growth factor-1, and angiogenin was obtained. Assessments were performed at baseline, and at the end of rTMS; psychocognitive tests were also repeated after 1, 3, and 6 months.

RESULTS

Chronic cerebrovascular disease was evident in five patients. No adverse/undesirable effect was reported. An improvement in mood was observed after rTMS but not at follow-up. Electrophysiological data to TMS remained unchanged, except for an increase in the right median MEP amplitude. TCD and neurotrophic/growth factors did not change.

CONCLUSIONS

We were unable to detect a relevant impact of high-frequency rTMS on mood, cognition, cortical microcircuits, neurotrophic/growth factors, and CBF. Cerebrovascular disease and exposure to multiple pharmacological treatments might have contributed.

A focus on Rho/ROCK signaling pathway: An emerging therapeutic target in depression

Depression is the most common mental health disorder worldwide; however, the exact cellular and molecular mechanisms of this major depressive disorder are unclear so far. Experimental studies have demonstrated that depression is associated with significant cognitive impairment, dendrite spine loss, and reduction in connectivity among neurons that contribute to symptoms associated with mood disorders. Rho/Rho-associated coiled-coil containing protein kinase (ROCK) receptors are exclusively expressed in the brain and Rho/ROCK signaling has gained considerable attention as it plays a crucial role in the development of neuronal architecture and structural plasticity. Chronic stress-induced activation of the Rho/ROCK signaling pathway promotes neuronal apoptosis and loss of neural processes and synapses. Interestingly, accumulated evidence has identified Rho/ROCK signaling pathways as a putative target for treating neurological disorders. Furthermore, inhibition of the Rho/ROCK signaling pathway has proven to be effective in different models of depression, which signify the potential benefits of clinical Rho/ROCK inhibition. The ROCK inhibitors extensively modulate antidepressant-related pathways which significantly control the synthesis of proteins, and neuron survival and ultimately led to the enhancement of synaptogenesis, connectivity, and improvement in behavior. Therefore, the present review refines the prevailing contribution of this signaling pathway in depression and highlighted preclinical shreds of evidence for employing ROCK inhibitors as disease-modifying targets along with possible underlying mechanisms in stress-associated depression.

Brain-derived neurotrophic factor serum levels following ketamine and esketamine intervention for treatment-resistant depression: secondary analysis from a randomized trial

OBJECTIVES

Evidence suggests that ketamine's influence on brain-derived neurotrophic factor (BDNF) might be involved in its mechanism of rapid antidepressant action. We aimed to evaluate the differential impact of ketamine and esketamine on serum BDNF levels and its association with response patterns in treatment-resistant depression (TRD).

METHODS

Participants (n = 53) are from a randomized, double-blind clinical trial comparing the efficacy of single-dose ketamine (0.5mg/kg, n = 27) and esketamine (0.25mg/kg, n = 26) in TRD. Depression severity was assessed before and 24 hours, 72 hours, and 7 days after the intervention, using the Montgomery-Åsberg Depression Rating Scale (MADRS). Blood samples were collected before infusion, 24 hours, and 7 days afterwards.

RESULTS

There were no significant changes in BDNF levels at post-infusion evaluation points, and no difference in BDNF levels comparing ketamine and esketamine. Both drugs exhibited similar therapeutic effect. There was no association between BDNF levels and response to treatment or severity of depressive symptoms.

CONCLUSION

There was no significant treatment impact on BDNF serum levels - neither with ketamine nor esketamine - despite therapeutic response. These results suggest that ketamine or esketamine intervention for TRD has no impact on BDNF levels measured at 24 hours and 7 days after the infusion.

Neurotoxic and cytoprotective mechanisms in the ischemic neocortex

Neuronal damage in ischemic stroke occurs due to permanent imbalance between the metabolic needs of the brain and the ability of the blood-vascular system to maintain glucose delivery and adequate gas exchange. Oxidative stress and excitotoxicity trigger complex processes of neuroinflammation, necrosis, and apoptosis of both neurons and glial cells. This review summarizes data on the structural and chemical changes in the neocortex and main cytoprotective effects induced by focal ischemic stroke. We focus on the expression of neurotrophins (NT) and molecular and cellular changes in neurovascular units in ischemic brain. We also discuss how these factors affect the apoptosis of cortical cells. Ischemic damage involves close interaction of a wide range of signaling molecules, each acting as an efficient marker of cell state in both the ischemic core and penumbra. NTs play the main regulatory role in brain tissue recovery after ischemic injury. Heterogeneous distribution of the BDNF, NT-3, and GDNF immunoreactivity is concordant with the selective response of different types of cortical neurons and glia to ischemic injury and allows mapping the position of viable neurons. Astrocytes are the central link in neurovascular coupling in ischemic brain by providing other cells with a wide range of vasotropic factors. The NT expression coincides with the distribution of reactive astrocytes, marking the boundaries of the penumbra. The development of ischemic stroke is accompanied by a dramatic change in the distribution of GDNF reactivity. In early ischemic period, it is mainly observed in cortical neurons, while in late one, the bulk of GDNF-positive cells are various types of glia, in particular, astrocytes. The proportion of GDNF-positive astrocytes increases gradually throughout the ischemic period. Some factors that exert cytoprotective effects in early ischemic period may display neurotoxic and pro-apoptotic effects later on. The number of apoptotic cells in the ischemic brain tissue correlates with the BDNF levels, corroborating its protective effects. Cytoprotection and neuroplasticity are two lines of brain protection and recovery after ischemic stroke. NTs can be considered an important link in these processes. To develop efficient pharmacological therapy for ischemic brain injury, we have to deepen our understanding of neurochemical adaptation of brain tissue to acute stroke.

Neurobiology of depression in Parkinson's disease: Insights into epidemiology, molecular mechanisms and treatment strategies

Parkinson's disease (PD) is characterized mainly by motor dysfunctions due to the progressive loss of dopaminergic neurons. However, PD patients experience a multitude of debilitating non-motor symptoms, including depression, which may have deleteriously detrimental effects on life. Depression is multifactorial and exhibits a bimodal progression in PD, but its underlying molecular mechanisms are poorly understood. Studies demonstrating the pathophysiology of depression in PD and the specific treatment strategies for depression-like symptoms in PD patients are largely lacking, often underrated, under-recognized and, consequently, inadequately/under-treated. Nevertheless, reports suggest that the incidence of depression is approximately 20-30% of PD patients and may precede the onset of motor symptoms. Diagnosing depression in PD becomes difficult due to the clinical overlap in symptomatology between the two diseases, and the nigrostriatal dysfunction alone is insufficient to explain depressive symptoms in PD. Therefore, the current study provides an overview of the molecular mechanisms underlying the development of depression in PD and new insights into developing current antidepressant strategies to treat depression in PD. This review will identify and understand the molecular pathological mechanisms of depression in PD that will fundamentally help tailoring therapeutic interventions for depressive symptoms in PD.

The Serum Brain-Derived Neurotrophic Factor Increases in Serotonin Reuptake Inhibitor Responders Patients with First-Episode, Drug-Naïve Major Depression

Brain-derived neurotrophic factor (BDNF) is a growth factor synthesized in the cell bodies of neurons and glia, which affects neuronal maturation, the survival of nervous system, and synaptic plasticity. BDNF play an important role in the pathophysiology of major depression (MD). The serum BDNF levels changed over time, or with the improvement in depressive symptoms. However, the change of serum BDNF during pharmacotherapy remains obscure in MDD. In particular, the changes in serum BDNF associated with pharmacotherapy have not yet been fully elucidated. The present study aimed to compare the changes in serum BDNF concentrations in first-episode, drug-naive patients with MD treated with antidepressants between treatment-response and treatment-nonresponse groups. The study included 35 inpatients and outpatients composed of 15 males and 20 females aged 36.7 ± 6.8 years at the Department of Psychiatry of our University Hospital. All patients met the DSM-5 diagnostic criteria for MD. The antidepressants administered included paroxetine, duloxetine, and escitalopram. Severity of depressive state was assessed using the 17-item HAMD before and 8 weeks after drug administration. Responders were defined as those whose total HAMD scores at 8 weeks had decreased by 50% or more compared to those before drug administration, while non-responders were those whose total HAMD scores had decreased by less than 50%. Here we showed that serum BDNF levels were not significantly different at any point between the two groups. The responder group, but not the non-responder group, showed statistically significant changes in serum BDNF 0 and serum BDNF 8. The results suggest that the changes of serum BDNF might differ between the two groups. The measurement of serum BDNF has the potential to be a useful predictor of pharmacotherapy in patients with first-episode, drug-naïve MD.

The effects of ketamine and classic hallucinogens on neurotrophic and inflammatory markers in unipolar treatment-resistant depression: a systematic review of clinical trials

Although results are still preliminary, ketamine and classical hallucinogens have shown promise in recent years as novel, fast-acting antidepressants, especially for the treatment of unipolar treatment-resistant depression (TRD). Depression also seems to be related to abnormal levels of peripheral inflammatory and neurotrophic biomarkers, which may one day help to diagnose of this disorder. In this context, this systematic review of clinical trials evaluated the current evidence that relates the antidepressant effects of ketamine and classical hallucinogens on TRD with changes in inflammatory and neurotrophic biomarkers. Twelve studies were found (n = 587), 2 with oral ayahuasca (1 mL/kg) and 10 with ketamine (mostly intravenous 0.5 mg/kg) administration. Results for all biomarkers assessed were contradictory and thus inconclusive. Randomized controlled trials with bigger samples and higher statistical power are warranted to clarify if peripheral biomarkers can confidently be used to indicate and measure ketamine's and classical hallucinogens' antidepressant effect. The PROSPERO ID for this study is CRD42021249089.

Surfactin Mitigates Dextran Sodium Sulfate-Induced Colitis and Behavioral Disorders in Mice by Mediating Gut-Brain-Axis Balance

Ulcerative colitis (UC) is associated with brain neurotransmitter disorders and intestinal dysbiosis. Bacillus amyloliquefaciens fmb50 produces the lipopeptide surfactin, which has a wide range of biological activities. However, the effects of surfactin on DSS-induced colitis have not been reported. In the present study, oral surfactin significantly ameliorated colitis in a mouse model and reduced depression-like behavior, such as slowed walking speed, shortened movement distance in the open field test, and weakened exploration ability in the light-dark shuttle test. Surfactin noticeably improved gut microbial dysbiosis, intestinal barrier dysfunction in the colon, and blood-brain barrier dysfunction in the brain. Furthermore, the colon levels of occludin were upregulated by 68.51%, and the brain levels of occludin and ZO-1 were upregulated by 77.81% and 36.42%, respectively. Surfactin supplementation also inhibited inflammatory responses by inactivating the tumor necrosis factor-α (TNF-α), nuclear factor kappa-B (NF-κB), and NLRP3 signaling pathways in the colon and brain. Thus, we believe that surfactin improved the behavioral disorders by upregulating the levels of 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), norepinephrine (NE), and brain-derived neurotrophic factor (BDNF), suppressing the inflammatory responses, and improving the blood-brain barrier dysfunction. Surfactin also reduced the abundances of gut microbes that are related to colitis, especially targeting facultative anaerobes of the phylum Proteobacteria, and it increased the abundance of beneficial bacteria such as Lactobacillus and unidentified Prevotella. Combined with its nontoxic nature observed in this long-term study in mice, oral surfactin might be a promising intervention strategy for preventing colitis by acting on the microbiota-gut-brain axis.

Deciphering the Effect of Different Genetic Variants on Hippocampal Subfield Volumes in the General Population

The aim of this study was to disentangle the effects of various genetic factors on hippocampal subfield volumes using three different approaches: a biologically driven candidate gene approach, a hypothesis-free GWAS approach, and a polygenic approach, where AD risk alleles are combined with a polygenic risk score (PRS). The impact of these genetic factors was investigated in a large dementia-free general population cohort from the Study of Health in Pomerania (SHIP, n = 1806). Analyses were performed using linear regression models adjusted for biological and environmental risk factors. Hippocampus subfield volume alterations were found for APOE ε4, BDNF Val, and 5-HTTLPR L allele carriers. In addition, we were able to replicate GWAS findings, especially for rs17178139 (MSRB3), rs1861979 (DPP4), rs7873551 (ASTN2), and rs572246240 (MAST4). Interaction analyses between the significant SNPs as well as the PRS for AD revealed no significant results. Our results confirm that hippocampal volume reductions are influenced by genetic variation, and that different variants reveal different association patterns that can be linked to biological processes in neurodegeneration. Thus, this study underlines the importance of specific genetic analyses in the quest for acquiring deeper insights into the biology of hippocampal volume loss, memory impairment, depression, and neurodegenerative diseases.

Repetitive transcranial magnetic stimulation promotes neurological functional recovery in rats with traumatic brain injury by upregulating synaptic plasticity-related proteins

Studies have shown that repetitive transcranial magnetic stimulation (rTMS) can enhance synaptic plasticity and improve neurological dysfunction. However, the mechanism through which rTMS can improve moderate traumatic brain injury remains poorly understood. In this study, we established rat models of moderate traumatic brain injury using Feeney’s weight-dropping method and treated them using rTMS. To help determine the mechanism of action, we measured levels of several important brain activity-related proteins and their mRNA. On the injured side of the brain, we found that rTMS increased the protein levels and mRNA expression of brain-derived neurotrophic factor, tropomyosin receptor kinase B, N-methyl-D-aspartic acid receptor 1, and phosphorylated cAMP response element binding protein, which are closely associated with the occurrence of long-term potentiation. rTMS also partially reversed the loss of synaptophysin after injury and promoted the remodeling of synaptic ultrastructure. These findings suggest that upregulation of synaptic plasticity-related protein expression is the mechanism through which rTMS promotes neurological function recovery after moderate traumatic brain injury.

Baseline Plasma BDNF Levelsare Associated with Antianhedonic Effects of Repeated-Dose Intravenous Ketamine in Major Depressive Disorder

OBJECTIVE

Evidence has shown that brain-derived neurotrophic factor (BDNF) is associated with anhedonia symptoms in major depressive disorder (MDD) patients, while the rapid antianhedonic effects of ketamine may occur independently of depressive symptoms. To our knowledge, the relationship between plasma BDNF (pBDNF) and the effect of repeated-dose intravenous ketamine on anhedonic symptoms has not been investigated.

METHODS

Seventy-five Chinese individuals with MDD received ketamine treatments. Anhedonia and pBDNF concentrations were evaluated with a subscale of the Montgomery-Åsberg Depression Rating Scale (MADRS) and enzyme-linked immunosorbent assay (ELISA) at baseline, day 13 and day 26.

RESULTS

Baseline pBDNF levels were associated with changes in anhedonic symptoms on day 13 (r=0.30, P=0.008). Interestingly, pBDNF concentrations were associated with changes in anhedonia symptomson day 26 (r= -0.32, P=0.02). Baseline pBDNF levels were higher in antianhedonic responders than in antianhedonic nonresponders (F=4.2, P=0.04). Ketaminereduced anhedonia symptoms in antianhedonic responders compared to nonresponders on days 13 and 26 (all Ps<0.05). The baseline high BDNF group had a lower level of anhedonia than the low BDNF group on days 13 (P<0.001) and 26 (P=0.01).

CONCLUSION

Our study suggests that baseline pBDNF concentrations may predict the antianhedonic effect in individuals with MDD treated with repeated doses of ketamine.

Fermented Perilla frutescens Ameliorates Depression-like Behavior in Sleep-Deprivation-Induced Stress Model

Excessive stress plays a critical role in the pathogenesis of mood disorders such as depression. Fermented natural products have recently attracted attention because of their health benefits. We evaluated the antidepressant-like efficacy of fermented Perilla frutescens (FPF), and its underlying mechanisms, in sleep deprivation (SD)-induced stress mice. SD-stressed mice revealed a remarkable increase in the immobility time in both forced swimming test and tail suspension test; this increase was ameliorated by treatment with FPF at doses of 100 and 150 mg/kg. FPF treatment also reduced the level of stress hormones such as corticosterone and adrenocorticotropic hormone. Additionally, FPF increased the levels of serotonin and dopamine which were significantly decreased in the brain tissues of SD-stressed mice. The increased expression of proinflammatory cytokines, such as TNF-α and IL1β, and the decreased expression of brain-derived neurotrophic factor (BDNF) in the stressed mice were significantly reversed by FPF treatment. Furthermore, FPF also increased phosphorylation of tropomyosin receptor kinase B (TrkB), extracellular regulated protein kinase (ERK), and cAMP response element binding protein (CREB). Among the six components isolated from FPF, protocatechuic acid and luteolin-7-O-glucuronide exhibited significant antidepressant-like effects, suggesting that they are major active components. These findings suggest that FPF has therapeutic potential for SD-induced stress, by correcting dysfunction of hypothalamic-pituitary-adrenal axis and modulating the BDNF/TrkB/ERK/CREB signaling pathway.